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Sample records for alveolata reveals plasticity

  1. Larval neurogenesis in Sabellaria alveolata reveals plasticity in polychaete neural patterning

    DEFF Research Database (Denmark)

    Brinkmann, Nora; Wanninger, Andreas

    2008-01-01

    . alveolata, two distinct modes of neuronal development are expressed, viz. the simultaneous formation of the first three segmental neurons of the peripheral nervous system on the one hand versus the sequential appearance of the ventral commissures on the other. This highlights the complex mechanisms...

  2. Recombination rate plasticity: revealing mechanisms by design

    Science.gov (United States)

    Sefick, Stephen; Rushton, Chase

    2017-01-01

    For over a century, scientists have known that meiotic recombination rates can vary considerably among individuals, and that environmental conditions can modify recombination rates relative to the background. A variety of external and intrinsic factors such as temperature, age, sex and starvation can elicit ‘plastic’ responses in recombination rate. The influence of recombination rate plasticity on genetic diversity of the next generation has interesting and important implications for how populations evolve. Further, many questions remain regarding the mechanisms and molecular processes that contribute to recombination rate plasticity. Here, we review 100 years of experimental work on recombination rate plasticity conducted in Drosophila melanogaster. We categorize this work into four major classes of experimental designs, which we describe via classic studies in D. melanogaster. Based on these studies, we highlight molecular mechanisms that are supported by experimental results and relate these findings to studies in other systems. We synthesize lessons learned from this model system into experimental guidelines for using recent advances in genotyping technologies, to study recombination rate plasticity in non-model organisms. Specifically, we recommend (1) using fine-scale genome-wide markers, (2) collecting time-course data, (3) including crossover distribution measurements, and (4) using mixed effects models to analyse results. To illustrate this approach, we present an application adhering to these guidelines from empirical work we conducted in Drosophila pseudoobscura. This article is part of the themed issue ‘Evolutionary causes and consequences of recombination rate variation in sexual organisms’. PMID:29109222

  3. 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.

  4. Interplay between abiotic factors and species assemblages mediated by the ecosystem engineer Sabellaria alveolata (Annelida: Polychaeta)

    Science.gov (United States)

    Jones, Auriane G.; Dubois, Stanislas F.; Desroy, Nicolas; Fournier, Jérôme

    2018-01-01

    Sabellaria alveolata is a gregarious polychaete that uses sand particles to build three-dimensional structures known as reefs, fixed atop rocks or built on soft sediments. These structures are known to modify the local grain-size distribution and to host a highly diversified macrofauna, altered when the reef undergoes disturbances. The goal of this study was to investigate the different sedimentary and biological changes associated with the presence of a S. alveolata reef over two contrasting seasons (late winter and late summer), and how these changes were linked. Three different sediments were considered: the engineered sediment (the actual reef), the associated sediment (the soft sediment surrounding the reef structures) and a control soft sediment (i.e. no reef structures in close proximity). Univariate and multivariate comparisons of grain-size distribution, soft sediment characteristics (organic matter content, chlorophyll a, pheopigments and carbohydrate concentrations) and macrofauna were conducted between the different sediment types at both seasons and between the two seasons for each sediment type. A distance-based redundancy analyses (dbRDA) was used to investigate the link between the different environmental parameters and the macrofauna assemblages. Finally, we focused on a disturbance continuum of the engineered sediments proxied by an increase in the mud present in these sediments. The effects of a continuous and increasing disturbance on the associated fauna were investigated using pairwise beta diversity indices (Sørensen and Bray-Curtis dissimilarities and their decomposition into turnover and nestedness). Results showed a significant effect of the reef on the local sediment distribution (coarser sediments compared to the control) and on the benthic primary production (higher in the associated sediments). At both seasons, S. alveolata biomass and sediment principal mode were the environmental parameters which best differentiated the engineered

  5. Reciprocal osmotic challenges reveal mechanisms of divergence in phenotypic plasticity in the killifish Fundulus heteroclitus.

    Science.gov (United States)

    Brennan, Reid S; Galvez, Fernando; Whitehead, Andrew

    2015-04-15

    The killifish Fundulus heteroclitus is an estuarine species with broad physiological plasticity, enabling acclimation to diverse stressors. Previous work suggests that freshwater populations expanded their physiology to accommodate low salinity environments; however, it is unknown whether this compromises their tolerance to high salinity. We used a comparative approach to investigate the mechanisms of a derived freshwater phenotype and the fate of an ancestral euryhaline phenotype after invasion of a freshwater environment. We compared physiological and transcriptomic responses to high- and low-salinity stress in fresh and brackish water populations and found an enhanced plasticity to low salinity in the freshwater population coupled with a reduced ability to acclimate to high salinity. Transcriptomic data identified genes with a conserved common response, a conserved salinity-dependent response and responses associated with population divergence. Conserved common acclimation responses revealed stress responses and alterations in cell-cycle regulation as important mechanisms in the general osmotic response. Salinity-specific responses included the regulation of genes involved in ion transport, intracellular calcium, energetic processes and cellular remodeling. Genes diverged between populations were primarily those showing salinity-specific expression and included those regulating polyamine homeostasis and the cell cycle. Additionally, when populations were matched with their native salinity, expression patterns were consistent with the concept of 'transcriptomic resilience', suggesting local adaptation. These findings provide insight into the fate of a plastic phenotype after a shift in environmental salinity and help to reveal mechanisms allowing for euryhalinity. © 2015. Published by The Company of Biologists Ltd.

  6. Species-Specific Mechanisms of Neuron Subtype Specification Reveal Evolutionary Plasticity of Amniote Brain Development

    Directory of Open Access Journals (Sweden)

    Tadashi Nomura

    2018-03-01

    Full Text Available Summary: Highly ordered brain architectures in vertebrates consist of multiple neuron subtypes with specific neuronal connections. However, the origin of and evolutionary changes in neuron specification mechanisms remain unclear. Here, we report that regulatory mechanisms of neuron subtype specification are divergent in developing amniote brains. In the mammalian neocortex, the transcription factors (TFs Ctip2 and Satb2 are differentially expressed in layer-specific neurons. In contrast, these TFs are co-localized in reptilian and avian dorsal pallial neurons. Multi-potential progenitors that produce distinct neuronal subtypes commonly exist in the reptilian and avian dorsal pallium, whereas a cis-regulatory element of avian Ctip2 exhibits attenuated transcription suppressive activity. Furthermore, the neuronal subtypes distinguished by these TFs are not tightly associated with conserved neuronal connections among amniotes. Our findings reveal the evolutionary plasticity of regulatory gene functions that contribute to species differences in neuronal heterogeneity and connectivity in developing amniote brains. : Neuronal heterogeneity is essential for assembling intricate neuronal circuits. Nomura et al. find that species-specific transcriptional mechanisms underlie diversities of excitatory neuron subtypes in mammalian and non-mammalian brains. Species differences in neuronal subtypes and connections suggest functional plasticity of regulatory genes for neuronal specification during amniote brain evolution. Keywords: Ctip2, Satb2, multi-potential progenitors, transcriptional regulation, neuronal connectivity

  7. Experimentally reduced root–microbe interactions reveal limited plasticity in functional root traits in Acer and Quercus

    Science.gov (United States)

    Lee, Mei-Ho; Comas, Louise H.; Callahan, Hilary S.

    2014-01-01

    Background and Aims Interactions between roots and soil microbes are critical components of below-ground ecology. It is essential to quantify the magnitude of root trait variation both among and within species, including variation due to plasticity. In addition to contextualizing the magnitude of plasticity relative to differences between species, studies of plasticity can ascertain if plasticity is predictable and whether an environmental factor elicits changes in traits that are functionally advantageous. Methods To compare functional traits and trait plasticities in fine root tissues with natural and reduced levels of colonization by microbial symbionts, trimmed and surface-sterilized root segments of 2-year-old Acer rubrum and Quercus rubra seedlings were manipulated. Segments were then replanted into satellite pots filled with control or heat-treated soil, both originally derived from a natural forest. Mycorrhizal colonization was near zero in roots grown in heat-treated soil; roots grown in control soil matched the higher colonization levels observed in unmanipulated root samples collected from field locations. Key Results Between-treatment comparisons revealed negligible plasticity for root diameter, branching intensity and nitrogen concentration across both species. Roots from treated soils had decreased tissue density (approx. 10–20 %) and increased specific root length (approx. 10–30 %). In contrast, species differences were significant and greater than treatment effects in traits other than tissue density. Interspecific trait differences were also significant in field samples, which generally resembled greenhouse samples. Conclusions The combination of experimental and field approaches was useful for contextualizing trait plasticity in comparison with inter- and intra-specific trait variation. Findings that root traits are largely species dependent, with the exception of root tissue density, are discussed in the context of current literature on root

  8. Experimentally reduced root-microbe interactions reveal limited plasticity in functional root traits in Acer and Quercus.

    Science.gov (United States)

    Lee, Mei-Ho; Comas, Louise H; Callahan, Hilary S

    2014-02-01

    Interactions between roots and soil microbes are critical components of below-ground ecology. It is essential to quantify the magnitude of root trait variation both among and within species, including variation due to plasticity. In addition to contextualizing the magnitude of plasticity relative to differences between species, studies of plasticity can ascertain if plasticity is predictable and whether an environmental factor elicits changes in traits that are functionally advantageous. To compare functional traits and trait plasticities in fine root tissues with natural and reduced levels of colonization by microbial symbionts, trimmed and surface-sterilized root segments of 2-year-old Acer rubrum and Quercus rubra seedlings were manipulated. Segments were then replanted into satellite pots filled with control or heat-treated soil, both originally derived from a natural forest. Mycorrhizal colonization was near zero in roots grown in heat-treated soil; roots grown in control soil matched the higher colonization levels observed in unmanipulated root samples collected from field locations. Between-treatment comparisons revealed negligible plasticity for root diameter, branching intensity and nitrogen concentration across both species. Roots from treated soils had decreased tissue density (approx. 10-20 %) and increased specific root length (approx. 10-30 %). In contrast, species differences were significant and greater than treatment effects in traits other than tissue density. Interspecific trait differences were also significant in field samples, which generally resembled greenhouse samples. The combination of experimental and field approaches was useful for contextualizing trait plasticity in comparison with inter- and intra-specific trait variation. Findings that root traits are largely species dependent, with the exception of root tissue density, are discussed in the context of current literature on root trait variation, interactions with symbionts and recent

  9. Water diffusion reveals networks that modulate multiregional morphological plasticity after repetitive brain stimulation.

    Science.gov (United States)

    Abe, Mitsunari; Fukuyama, Hidenao; Mima, Tatsuya

    2014-03-25

    Repetitive brain stimulation protocols induce plasticity in the stimulated site in brain slice models. Recent evidence from network models has indicated that additional plasticity-related changes occur in nonstimulated remote regions. Despite increasing use of brain stimulation protocols in experimental and clinical settings, the neural substrates underlying the additional effects in remote regions are unknown. Diffusion-weighted MRI (DWI) probes water diffusion and can be used to estimate morphological changes in cortical tissue that occur with the induction of plasticity. Using DWI techniques, we estimated morphological changes induced by application of repetitive transcranial magnetic stimulation (rTMS) over the left primary motor cortex (M1). We found that rTMS altered water diffusion in multiple regions including the left M1. Notably, the change in water diffusion was retained longest in the left M1 and remote regions that had a correlation of baseline fluctuations in water diffusion before rTMS. We conclude that synchronization of water diffusion at rest between stimulated and remote regions ensures retention of rTMS-induced changes in water diffusion in remote regions. Synchronized fluctuations in the morphology of cortical microstructures between stimulated and remote regions might identify networks that allow retention of plasticity-related morphological changes in multiple regions after brain stimulation protocols. These results increase our understanding of the effects of brain stimulation-induced plasticity on multiregional brain networks. DWI techniques could provide a tool to evaluate treatment effects of brain stimulation protocols in patients with brain disorders.

  10. Reaction-diffusion-like formalism for plastic neural networks reveals dissipative solitons at criticality

    Science.gov (United States)

    Grytskyy, Dmytro; Diesmann, Markus; Helias, Moritz

    2016-06-01

    Self-organized structures in networks with spike-timing dependent synaptic plasticity (STDP) are likely to play a central role for information processing in the brain. In the present study we derive a reaction-diffusion-like formalism for plastic feed-forward networks of nonlinear rate-based model neurons with a correlation sensitive learning rule inspired by and being qualitatively similar to STDP. After obtaining equations that describe the change of the spatial shape of the signal from layer to layer, we derive a criterion for the nonlinearity necessary to obtain stable dynamics for arbitrary input. We classify the possible scenarios of signal evolution and find that close to the transition to the unstable regime metastable solutions appear. The form of these dissipative solitons is determined analytically and the evolution and interaction of several such coexistent objects is investigated.

  11. Local Plasticity of Al Thin Films as Revealed by X-Ray Microdiffraction

    Science.gov (United States)

    Spolenak, R.; Brown, W. L.; Tamura, N.; MacDowell, A. A.; Celestre, R. S.; Padmore, H. A.; Valek, B.; Bravman, J. C.; Marieb, T.; Fujimoto, H.; Batterman, B. W.; Patel, J. R.

    2003-03-01

    Grain-to-grain interactions dominate the plasticity of Al thin films and establish effective length scales smaller than the grain size. We have measured large strain distributions and their changes under plastic strain in 1.5-μm-thick Al0.5%Cu films using a 0.8-μm-diameter white x-ray probe at the Advanced Light Source. Strain distributions arise not only from the distribution of grain sizes and orientation, but also from the differences in grain shape and from stress environment. Multiple active glide plane domains have been found within single grains. Large grains behave like multiple smaller grains even before a dislocation substructure can evolve.

  12. Sensorimotor Plasticity after Music-Supported Therapy in Chronic Stroke Patients Revealed by Transcranial Magnetic Stimulation

    OpenAIRE

    Amengual, J. L.; Rojo, N.; Veciana De Las Heras, Misericordia; Marco-Pallarés, J.; Grau-Sánchez, J.; Schneider, S.; Vaquero, L.; Juncadella Puig, Montserrat; Montero Homs, Jordi; Mohammadi, B.; Rubio, F.; Rueda, N.; Duarte, E.; Grau Fonollosa, Carles; Altenmuller, E.

    2014-01-01

    BACKGROUND: Several recently developed therapies targeting motor disabilities in stroke sufferers have shown to be more effective than standard neurorehabilitation approaches. In this context, several basic studies demonstrated that music training produces rapid neuroplastic changes in motor-related brain areas. Music-supported therapy has been recently developed as a new motor rehabilitation intervention. METHODS AND RESULTS: In order to explore the plasticity effects of music-supported ther...

  13. Conditional RARα Knockout Mice Reveal Acute Requirement for Retinoic Acid and RARα in Homeostatic Plasticity

    Directory of Open Access Journals (Sweden)

    Federica eSarti

    2012-02-01

    Full Text Available All-trans retinoic acid (RA plays important roles in brain development through regulating gene transcription. Recently, a novel postdevelopmental role of RA in mature brain was proposed. Specifically, RA rapidly enhanced excitatory synaptic transmission independent of transcriptional regulation. RA synthesis was induced when excitatory synaptic transmission was chronically blocked, and RA then activated dendritic protein synthesis and synaptic insertion of homomeric GluA1 AMPA receptors, thereby compensating for the loss of neuronal activity in a homeostatic fashion. This action of RA was suggested to be mediated by its canonical receptor RARα but no genetic evidence was available. Thus, we here tested the fundamental requirement of RARα in homeostatic plasticity using conditional RARα knockout mice, and additionally performed a structure-function analysis of RARα. We show that acutely deleting RARα in neurons eliminated RA’s effect on excitatory synaptic transmission, and inhibited activity blockade-induced homeostatic synaptic plasticity. By expressing various RARα rescue constructs in RARα knockout neurons, we found that the DNA-binding domain of RARα was dispensable for its role in regulating synaptic strength, further supporting the notion that RA and RARα act in a non-transcriptional manner in this context. By contrast, the ligand-binding domain (LBD and the mRNA-binding domain (F-domain are both necessary and sufficient for the function of RARα in homeostatic plasticity. Furthermore, we found that homeostatic regulation performed by the LBD/F domains leads to insertion of calcium-permeable AMPA receptors. Our results confirm with unequivocal genetic approaches that RA and RARα perform essential non-transcriptional functions in regulating synaptic strength, and establish a functional link between the various domains of RARα and their involvement in regulating protein synthesis and excitatory synaptic transmission during

  14. Sensorimotor plasticity after music-supported therapy in chronic stroke patients revealed by transcranial magnetic stimulation.

    Directory of Open Access Journals (Sweden)

    Julià L Amengual

    Full Text Available BACKGROUND: Several recently developed therapies targeting motor disabilities in stroke sufferers have shown to be more effective than standard neurorehabilitation approaches. In this context, several basic studies demonstrated that music training produces rapid neuroplastic changes in motor-related brain areas. Music-supported therapy has been recently developed as a new motor rehabilitation intervention. METHODS AND RESULTS: In order to explore the plasticity effects of music-supported therapy, this therapeutic intervention was applied to twenty chronic stroke patients. Before and after the music-supported therapy, transcranial magnetic stimulation was applied for the assessment of excitability changes in the motor cortex and a 3D movement analyzer was used for the assessment of motor performance parameters such as velocity, acceleration and smoothness in a set of diadochokinetic movement tasks. Our results suggest that the music-supported therapy produces changes in cortical plasticity leading the improvement of the subjects' motor performance. CONCLUSION: Our findings represent the first evidence of the neurophysiological changes induced by this therapy in chronic stroke patients, and their link with the amelioration of motor performance. Further studies are needed to confirm our observations.

  15. Sensorimotor plasticity after music-supported therapy in chronic stroke patients revealed by transcranial magnetic stimulation.

    Science.gov (United States)

    Amengual, Julià L; Rojo, Nuria; Veciana de Las Heras, Misericordia; Marco-Pallarés, Josep; Grau-Sánchez, Jennifer; Schneider, Sabine; Vaquero, Lucía; Juncadella, Montserrat; Montero, Jordi; Mohammadi, Bahram; Rubio, Francisco; Rueda, Nohora; Duarte, Esther; Grau, Carles; Altenmüller, Eckart; Münte, Thomas F; Rodríguez-Fornells, Antoni

    2013-01-01

    Several recently developed therapies targeting motor disabilities in stroke sufferers have shown to be more effective than standard neurorehabilitation approaches. In this context, several basic studies demonstrated that music training produces rapid neuroplastic changes in motor-related brain areas. Music-supported therapy has been recently developed as a new motor rehabilitation intervention. In order to explore the plasticity effects of music-supported therapy, this therapeutic intervention was applied to twenty chronic stroke patients. Before and after the music-supported therapy, transcranial magnetic stimulation was applied for the assessment of excitability changes in the motor cortex and a 3D movement analyzer was used for the assessment of motor performance parameters such as velocity, acceleration and smoothness in a set of diadochokinetic movement tasks. Our results suggest that the music-supported therapy produces changes in cortical plasticity leading the improvement of the subjects' motor performance. Our findings represent the first evidence of the neurophysiological changes induced by this therapy in chronic stroke patients, and their link with the amelioration of motor performance. Further studies are needed to confirm our observations.

  16. Sensorimotor Plasticity after Music-Supported Therapy in Chronic Stroke Patients Revealed by Transcranial Magnetic Stimulation

    Science.gov (United States)

    Amengual, Julià L.; Rojo, Nuria; Veciana de las Heras, Misericordia; Marco-Pallarés, Josep; Grau-Sánchez, Jennifer; Schneider, Sabine; Vaquero, Lucía; Juncadella, Montserrat; Montero, Jordi; Mohammadi, Bahram; Rubio, Francisco; Rueda, Nohora; Duarte, Esther; Grau, Carles; Altenmüller, Eckart; Münte, Thomas F.; Rodríguez-Fornells, Antoni

    2013-01-01

    Background Several recently developed therapies targeting motor disabilities in stroke sufferers have shown to be more effective than standard neurorehabilitation approaches. In this context, several basic studies demonstrated that music training produces rapid neuroplastic changes in motor-related brain areas. Music-supported therapy has been recently developed as a new motor rehabilitation intervention. Methods and Results In order to explore the plasticity effects of music-supported therapy, this therapeutic intervention was applied to twenty chronic stroke patients. Before and after the music-supported therapy, transcranial magnetic stimulation was applied for the assessment of excitability changes in the motor cortex and a 3D movement analyzer was used for the assessment of motor performance parameters such as velocity, acceleration and smoothness in a set of diadochokinetic movement tasks. Our results suggest that the music-supported therapy produces changes in cortical plasticity leading the improvement of the subjects' motor performance. Conclusion Our findings represent the first evidence of the neurophysiological changes induced by this therapy in chronic stroke patients, and their link with the amelioration of motor performance. Further studies are needed to confirm our observations. PMID:23613966

  17. Pushing the Limits: Cognitive, Affective, & Neural Plasticity Revealed by an Intensive Multifaceted Intervention

    Directory of Open Access Journals (Sweden)

    Michael David Mrazek

    2016-03-01

    Full Text Available Scientific understanding of how much the adult brain can be shaped by experience requires examination of how multiple influences combine to elicit cognitive, affective, and neural plasticity. Using an intensive multifaceted intervention, we discovered that substantial and enduring improvements can occur in parallel across multiple cognitive and neuroimaging measures in healthy young adults. The intervention elicited substantial improvements in physical health, working memory, standardized test performance, mood, self-esteem, self-efficacy, mindfulness, and life satisfaction. Improvements in mindfulness were associated with increased degree centrality of the insula, greater functional connectivity between insula and somatosensory cortex, and reduced functional connectivity between posterior cingulate cortex and somatosensory cortex. Improvements in working memory and reading comprehension were associated with increased degree centrality of a region within the middle temporal gyrus that was extensively and predominately integrated with the executive control network. The scope and magnitude of the observed improvements represent the most extensive demonstration to date of the considerable human capacity for change. These findings point to higher limits for rapid and concurrent cognitive, affective, and neural plasticity than is widely assumed.

  18. Intraoperative mapping during repeat awake craniotomy reveals the functional plasticity of adult cortex.

    Science.gov (United States)

    Southwell, Derek G; Hervey-Jumper, Shawn L; Perry, David W; Berger, Mitchel S

    2016-05-01

    OBJECT To avoid iatrogenic injury during the removal of intrinsic cerebral neoplasms such as gliomas, direct electrical stimulation (DES) is used to identify cortical and subcortical white matter pathways critical for language, motor, and sensory function. When a patient undergoes more than 1 brain tumor resection as in the case of tumor recurrence, the use of DES provides an unusual opportunity to examine brain plasticity in the setting of neurological disease. METHODS The authors examined 561 consecutive cases in which patients underwent DES mapping during surgery forglioma resection. "Positive" and "negative" sites-discrete cortical regions where electrical stimulation did (positive) or did not (negative) produce transient sensory, motor, or language disturbance-were identified prior to tumor resection and documented by intraoperative photography for categorization into functional maps. In this group of 561 patients, 18 were identified who underwent repeat surgery in which 1 or more stimulation sites overlapped with those tested during the initial surgery. The authors compared intraoperative sensory, motor, or language mapping results between initial and repeat surgeries, and evaluated the clinical outcomes for these patients. RESULTS A total of 117 sites were tested for sensory (7 sites, 6.0%), motor (9 sites, 7.7%), or language (101 sites, 86.3%) function during both initial and repeat surgeries. The mean interval between surgical procedures was 4.1 years. During initial surgeries, 95 (81.2%) of 117 sites were found to be negative and 22 (18.8%) of 117 sites were found to be positive. During repeat surgeries, 103 (88.0%) of 117 sites were negative and 14 (12.0%) of 117 were positive. Of the 95 sites that were negative at the initial surgery, 94 (98.9%) were also negative at the repeat surgery, while 1 (1.1%) site was found to be positive. Of the 22 sites that were initially positive, 13 (59.1%) remained positive at repeat surgery, while 9 (40.9%) had become

  19. Cytology of DNA Replication Reveals Dynamic Plasticity of Large-Scale Chromatin Fibers.

    Science.gov (United States)

    Deng, Xiang; Zhironkina, Oxana A; Cherepanynets, Varvara D; Strelkova, Olga S; Kireev, Igor I; Belmont, Andrew S

    2016-09-26

    In higher eukaryotic interphase nuclei, the 100- to >1,000-fold linear compaction of chromatin is difficult to reconcile with its function as a template for transcription, replication, and repair. It is challenging to imagine how DNA and RNA polymerases with their associated molecular machinery would move along the DNA template without transient decondensation of observed large-scale chromatin "chromonema" fibers [1]. Transcription or "replication factory" models [2], in which polymerases remain fixed while DNA is reeled through, are similarly difficult to conceptualize without transient decondensation of these chromonema fibers. Here, we show how a dynamic plasticity of chromatin folding within large-scale chromatin fibers allows DNA replication to take place without significant changes in the global large-scale chromatin compaction or shape of these large-scale chromatin fibers. Time-lapse imaging of lac-operator-tagged chromosome regions shows no major change in the overall compaction of these chromosome regions during their DNA replication. Improved pulse-chase labeling of endogenous interphase chromosomes yields a model in which the global compaction and shape of large-Mbp chromatin domains remains largely invariant during DNA replication, with DNA within these domains undergoing significant movements and redistribution as they move into and then out of adjacent replication foci. In contrast to hierarchical folding models, this dynamic plasticity of large-scale chromatin organization explains how localized changes in DNA topology allow DNA replication to take place without an accompanying global unfolding of large-scale chromatin fibers while suggesting a possible mechanism for maintaining epigenetic programming of large-scale chromatin domains throughout DNA replication. Copyright © 2016 Elsevier Ltd. All rights reserved.

  20. Field-portable-XRF reveals the ubiquity of antimony in plastic consumer products.

    Science.gov (United States)

    Turner, Andrew; Filella, Montserrat

    2017-04-15

    Very little systematic information exists on the occurrence and concentrations of antimony (Sb) in consumer products. In this study, a Niton XL3t field-portable-X-ray fluorescence (FP-XRF) spectrometer was deployed in situ and in the laboratory to provide quantitative information on Sb dissipated in plastic items and fixtures (including rubber, textile and foamed materials) from the domestic, school, vehicular and office settings. The metalloid was detected in 18% of over 800 measurements performed, with concentrations ranging from about 60 to 60,000μgg -1 . The highest concentrations were encountered in white, electronic casings and in association with similar concentrations of Br, consistent with the use of antimony oxides (e.g. Sb 2 O 3 ) as synergistic flame retardants. Concentrations above 1000μgg -1 , and with or without Br, were also encountered in paints, piping and hosing, adhesives, whiteboards, Christmas decorations, Lego blocks, document carriers, garden furniture, upholstered products and interior panels of private motor vehicles. Lower concentrations of Sb were encountered in a wide variety of items but its presence (without Br) in food tray packaging, single-use drinks bottles, straws and small toys were of greatest concern from a human health perspective. While the latter observations are consistent with the use of antimony compounds as catalysts in the production of polyethylene terephthalate, co-association of Sb and Br in many products not requiring flame retardancy suggests that electronic casings are widely recycled. Further research is required into the mobility of Sb when dissipated in new, recycled and aged polymeric materials. Copyright © 2017 Elsevier B.V. All rights reserved.

  1. Analysis of global gene expression in Brachypodium distachyon reveals extensive network plasticity in response to abiotic stress.

    Directory of Open Access Journals (Sweden)

    Henry D Priest

    Full Text Available Brachypodium distachyon is a close relative of many important cereal crops. Abiotic stress tolerance has a significant impact on productivity of agriculturally important food and feedstock crops. Analysis of the transcriptome of Brachypodium after chilling, high-salinity, drought, and heat stresses revealed diverse differential expression of many transcripts. Weighted Gene Co-Expression Network Analysis revealed 22 distinct gene modules with specific profiles of expression under each stress. Promoter analysis implicated short DNA sequences directly upstream of module members in the regulation of 21 of 22 modules. Functional analysis of module members revealed enrichment in functional terms for 10 of 22 network modules. Analysis of condition-specific correlations between differentially expressed gene pairs revealed extensive plasticity in the expression relationships of gene pairs. Photosynthesis, cell cycle, and cell wall expression modules were down-regulated by all abiotic stresses. Modules which were up-regulated by each abiotic stress fell into diverse and unique gene ontology GO categories. This study provides genomics resources and improves our understanding of abiotic stress responses of Brachypodium.

  2. The mirror neuron system as revealed through neonatal imitation: presence from birth, predictive power and evidence of plasticity.

    Science.gov (United States)

    Simpson, Elizabeth A; Murray, Lynne; Paukner, Annika; Ferrari, Pier F

    2014-01-01

    There is strong evidence that neonates imitate previously unseen behaviours. These behaviours are predominantly used in social interactions, demonstrating neonates' ability and motivation to engage with others. Research on neonatal imitation can provide a wealth of information about the early mirror neuron system (MNS), namely its functional characteristics, its plasticity from birth and its relation to skills later in development. Although numerous studies document the existence of neonatal imitation in the laboratory, little is known about its natural occurrence during parent-infant interactions and its plasticity as a consequence of experience. We review these critical aspects of imitation, which we argue are necessary for understanding the early action-perception system. We address common criticisms and misunderstandings about neonatal imitation and discuss methodological differences among studies. Recent work reveals that individual differences in neonatal imitation positively correlate with later social, cognitive and motor development. We propose that such variation in neonatal imitation could reflect important individual differences of the MNS. Although postnatal experience is not necessary for imitation, we present evidence that neonatal imitation is influenced by experience in the first week of life.

  3. Comparative Genomics of Methanopyrus sp. SNP6 and KOL6 Revealing Genomic Regions of Plasticity Implicated in Extremely Thermophilic Profiles

    Directory of Open Access Journals (Sweden)

    Zhiliang Yu

    2017-07-01

    Full Text Available Methanopyrus spp. are usually isolated from harsh niches, such as high osmotic pressure and extreme temperature. However, the molecular mechanisms for their environmental adaption are poorly understood. Archaeal species is commonly considered as primitive organism. The evolutional placement of archaea is a fundamental and intriguing scientific question. We sequenced the genomes of Methanopyrus strains SNP6 and KOL6 isolated from the Atlantic and Iceland, respectively. Comparative genomic analysis revealed genetic diversity and instability implicated in niche adaption, including a number of transporter- and integrase/transposase-related genes. Pan-genome analysis also defined the gene pool of Methanopyrus spp., in addition of ~120-Kb genomic region of plasticity impacting cognate genomic architecture. We believe that Methanopyrus genomics could facilitate efficient investigation/recognition of archaeal phylogenetic diverse patterns, as well as improve understanding of biological roles and significance of these versatile microbes.

  4. Small angle X-ray scattering study of calreticulin reveals conformational plasticity

    DEFF Research Database (Denmark)

    Toft, Katrine Nørgaard; Larsen, Nanna; Jørgensen, Flemming Steen

    2008-01-01

    . The data from the calreticulin monomer reveal the shape of calreticulin in solution: The previously structurally un-described C-terminal is seen as a globular domain, and the P-domain beta-hairpin extends from the N-domain in a spiral like conformation. In the calreticulin solution dimer, the N-, C-, and P......-domains are easily identified, and the P-domain is in an extended conformation connecting to the second calreticulin molecule. The SAXS solution data enables the construction of a medium-resolution model of calreticulin. In the light of the unresolved chaperone mechanism of calreticulin and calnexin, we discuss...

  5. Striking Plasticity of CRISPR-Cas9 and Key Role of Non-target DNA, as Revealed by Molecular Simulations.

    Science.gov (United States)

    Palermo, Giulia; Miao, Yinglong; Walker, Ross C; Jinek, Martin; McCammon, J Andrew

    2016-10-26

    The CRISPR (clustered regularly interspaced short palindromic repeats)-Cas9 system recently emerged as a transformative genome-editing technology that is innovating basic bioscience and applied medicine and biotechnology. The endonuclease Cas9 associates with a guide RNA to match and cleave complementary sequences in double stranded DNA, forming an RNA:DNA hybrid and a displaced non-target DNA strand. Although extensive structural studies are ongoing, the conformational dynamics of Cas9 and its interplay with the nucleic acids during association and DNA cleavage are largely unclear. Here, by employing multi-microsecond time scale molecular dynamics, we reveal the conformational plasticity of Cas9 and identify key determinants that allow its large-scale conformational changes during nucleic acid binding and processing. We show how the "closure" of the protein, which accompanies nucleic acid binding, fundamentally relies on highly coupled and specific motions of the protein domains, collectively initiating the prominent conformational changes needed for nucleic acid association. We further reveal a key role of the non-target DNA during the process of activation of the nuclease HNH domain, showing how the nontarget DNA positioning triggers local conformational changes that favor the formation of a catalytically competent Cas9. Finally, a remarkable conformational plasticity is identified as an intrinsic property of the HNH domain, constituting a necessary element that allows for the HNH repositioning. These novel findings constitute a reference for future experimental studies aimed at a full characterization of the dynamic features of the CRISPR-Cas9 system, and-more importantly-call for novel structure engineering efforts that are of fundamental importance for the rational design of new genome-engineering applications.

  6. Simulated body temperature rhythms reveal the phase-shifting behavior and plasticity of mammalian circadian oscillators

    Science.gov (United States)

    Saini, Camille; Morf, Jörg; Stratmann, Markus; Gos, Pascal; Schibler, Ueli

    2012-01-01

    The circadian pacemaker in the suprachiasmatic nuclei (SCN) of the hypothalamus maintains phase coherence in peripheral cells through metabolic, neuronal, and humoral signaling pathways. Here, we investigated the role of daily body temperature fluctuations as possible systemic cues in the resetting of peripheral oscillators. Using precise temperature devices in conjunction with real-time monitoring of the bioluminescence produced by circadian luciferase reporter genes, we showed that simulated body temperature cycles of mice and even humans, with daily temperature differences of only 3°C and 1°C, respectively, could gradually synchronize circadian gene expression in cultured fibroblasts. The time required for establishing the new steady-state phase depended on the reporter gene, but after a few days, the expression of each gene oscillated with a precise phase relative to that of the temperature cycles. Smooth temperature oscillations with a very small amplitude could synchronize fibroblast clocks over a wide temperature range, and such temperature rhythms were also capable of entraining gene expression cycles to periods significantly longer or shorter than 24 h. As revealed by genetic loss-of-function experiments, heat-shock factor 1 (HSF1), but not HSF2, was required for the efficient synchronization of fibroblast oscillators to simulated body temperature cycles. PMID:22379191

  7. Simulated body temperature rhythms reveal the phase-shifting behavior and plasticity of mammalian circadian oscillators.

    Science.gov (United States)

    Saini, Camille; Morf, Jörg; Stratmann, Markus; Gos, Pascal; Schibler, Ueli

    2012-03-15

    The circadian pacemaker in the suprachiasmatic nuclei (SCN) of the hypothalamus maintains phase coherence in peripheral cells through metabolic, neuronal, and humoral signaling pathways. Here, we investigated the role of daily body temperature fluctuations as possible systemic cues in the resetting of peripheral oscillators. Using precise temperature devices in conjunction with real-time monitoring of the bioluminescence produced by circadian luciferase reporter genes, we showed that simulated body temperature cycles of mice and even humans, with daily temperature differences of only 3°C and 1°C, respectively, could gradually synchronize circadian gene expression in cultured fibroblasts. The time required for establishing the new steady-state phase depended on the reporter gene, but after a few days, the expression of each gene oscillated with a precise phase relative to that of the temperature cycles. Smooth temperature oscillations with a very small amplitude could synchronize fibroblast clocks over a wide temperature range, and such temperature rhythms were also capable of entraining gene expression cycles to periods significantly longer or shorter than 24 h. As revealed by genetic loss-of-function experiments, heat-shock factor 1 (HSF1), but not HSF2, was required for the efficient synchronization of fibroblast oscillators to simulated body temperature cycles.

  8. Single-Cell (Meta-Genomics of a Dimorphic Candidatus Thiomargarita nelsonii Reveals Genomic Plasticity

    Directory of Open Access Journals (Sweden)

    Beverly E. Flood

    2016-05-01

    Full Text Available The genus Thiomargarita includes the world’s largest bacteria. But as uncultured organisms, their physiology, metabolism, and basis for their gigantism are not well understood. Thus a genomics approach, applied to a single Candidatus Thiomargarita nelsonii cell was employed to explore the genetic potential of one of these enigmatic giant bacteria. The Thiomargarita cell was obtained from an assemblage of budding Ca. T. nelsonii attached to a provannid gastropod shell from Hydrate Ridge, a methane seep offshore of Oregon, USA. Here we present a manually curated genome of Bud S10 resulting from a hybrid assembly of long Pacific Biosciences and short Illumina sequencing reads. With respect to inorganic carbon fixation and sulfur oxidation pathways, the Ca. T. nelsonii Hydrate Ridge Bud S10 genome was similar to marine sister taxa within the family Beggiatoaceae. However, the Bud S10 genome contains genes suggestive of the genetic potential for lithotrophic growth on arsenite and perhaps hydrogen. The genome also revealed that Bud S10 likely respires nitrate via two pathways: a complete denitrification pathway and a dissimilatory nitrate reduction to ammonia pathway. Both pathways have been predicted, but not previously fully elucidated, in the genomes of other large, vacuolated, sulfur-oxidizing bacteria.Surprisingly, the genome also had a high number of unusual features for a bacterium to include the largest number of metacaspases and introns ever reported in a bacterium. Also present, are a large number of other mobile genetic elements, such as insertion sequence transposable elements and miniature inverted-repeat transposable elements (MITEs. In some cases, mobile genetic elements disrupted key genes in metabolic pathways. For example, a MITE interrupts hupL, which encodes the large subunit of the hydrogenase in hydrogen oxidation. Moreover, we detected a group I intron in one of the most critical genes in the sulfur oxidation pathway, dsr

  9. 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.

  10. Crystal plasticity in Cu damascene interconnect lines undergoing electromigration as revealed by synchrotron x-ray microdiffraction

    Science.gov (United States)

    Budiman, A. S.; Nix, W. D.; Tamura, N.; Valek, B. C.; Gadre, K.; Maiz, J.; Spolenak, R.; Patel, J. R.

    2006-06-01

    Plastic deformation was observed in damascene Cu interconnect test structures during an in situ electromigration experiment and before the onset of visible microstructural damage (voiding, hillock formation). We show here, using a synchrotron technique of white beam x-ray microdiffraction, that the extent of this electromigration-induced plasticity is dependent on the linewidth. In wide lines, plastic deformation manifests itself as grain bending and the formation of subgrain structures, while only grain rotation is observed in the narrower lines. The deformation geometry leads us to conclude that dislocations introduced by plastic flow lie predominantly in the direction of electron flow and may provide additional easy paths for the transport of point defects. Since these findings occur long before any observable voids or hillocks are formed, they may have direct bearing on the final failure stages of electromigration.

  11. Plasticity mechanisms in ultrafine grained freestanding aluminum thin films revealed by in-situ transmission electron microscopy nanomechanical testing

    International Nuclear Information System (INIS)

    Idrissi, Hosni; Kobler, Aaron; Amin-Ahmadi, Behnam; Schryvers, Dominique; Coulombier, Michael; Pardoen, Thomas; Galceran, Montserrat; Godet, Stéphane; Raskin, Jean-Pierre; Kübel, Christian

    2014-01-01

    In-situ bright field transmission electron microscopy (TEM) nanomechanical tensile testing and in-situ automated crystallographic orientation mapping in TEM were combined to unravel the elementary mechanisms controlling the plasticity of ultrafine grained Aluminum freestanding thin films. The characterizations demonstrate that deformation proceeds with a transition from grain rotation to intragranular dislocation glide and starvation plasticity mechanism at about 1% deformation. The grain rotation is not affected by the character of the grain boundaries. No grain growth or twinning is detected

  12. Plasticity mechanisms in ultrafine grained freestanding aluminum thin films revealed by in-situ transmission electron microscopy nanomechanical testing

    Energy Technology Data Exchange (ETDEWEB)

    Idrissi, Hosni, E-mail: hosni.idrissi@ua.ac.be [EMAT, University of Antwerp, Groenenborgerlaan 171, B-2020 Antwerp (Belgium); Institute of Mechanics, Materials and Civil Engineering, Université catholique de Louvain, Place Sainte Barbe 2, B-1348 Louvain-La-Neuve (Belgium); Kobler, Aaron [Institute of Nanotechnology (INT) and Karlsruhe Nano Micro Facility (KNMF), Karlsruhe Institute of Technology - KIT, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen (Germany); Joint Research Laboratory Nanomaterials (KIT and TUD) at Technische Universität Darmstadt (TUD), Petersenstr. 32, 64287 Darmstadt (Germany); Amin-Ahmadi, Behnam; Schryvers, Dominique [EMAT, University of Antwerp, Groenenborgerlaan 171, B-2020 Antwerp (Belgium); Coulombier, Michael; Pardoen, Thomas [Institute of Mechanics, Materials and Civil Engineering, Université catholique de Louvain, Place Sainte Barbe 2, B-1348 Louvain-La-Neuve (Belgium); Galceran, Montserrat; Godet, Stéphane [Matters and Materials Department, Université Libre de Bruxelles, 50 Av. FD Roosevelt CP194/03, 1050 Brussels (Belgium); Raskin, Jean-Pierre [Information and Communications Technologies, Electronics and Applied Mathematics (ICTEAM), Microwave Laboratory, Université catholique de Louvain, B-1348 Louvain-la-Neuve (Belgium); Kübel, Christian [Institute of Nanotechnology (INT) and Karlsruhe Nano Micro Facility (KNMF), Karlsruhe Institute of Technology - KIT, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen (Germany)

    2014-03-10

    In-situ bright field transmission electron microscopy (TEM) nanomechanical tensile testing and in-situ automated crystallographic orientation mapping in TEM were combined to unravel the elementary mechanisms controlling the plasticity of ultrafine grained Aluminum freestanding thin films. The characterizations demonstrate that deformation proceeds with a transition from grain rotation to intragranular dislocation glide and starvation plasticity mechanism at about 1% deformation. The grain rotation is not affected by the character of the grain boundaries. No grain growth or twinning is detected.

  13. Model-Driven Analysis of Eyeblink Classical Conditioning Reveals the Underlying Structure of Cerebellar Plasticity and Neuronal Activity.

    Science.gov (United States)

    Antonietti, Alberto; Casellato, Claudia; D'Angelo, Egidio; Pedrocchi, Alessandra

    The cerebellum plays a critical role in sensorimotor control. However, how the specific circuits and plastic mechanisms of the cerebellum are engaged in closed-loop processing is still unclear. We developed an artificial sensorimotor control system embedding a detailed spiking cerebellar microcircuit with three bidirectional plasticity sites. This proved able to reproduce a cerebellar-driven associative paradigm, the eyeblink classical conditioning (EBCC), in which a precise time relationship between an unconditioned stimulus (US) and a conditioned stimulus (CS) is established. We challenged the spiking model to fit an experimental data set from human subjects. Two subsequent sessions of EBCC acquisition and extinction were recorded and transcranial magnetic stimulation (TMS) was applied on the cerebellum to alter circuit function and plasticity. Evolutionary algorithms were used to find the near-optimal model parameters to reproduce the behaviors of subjects in the different sessions of the protocol. The main finding is that the optimized cerebellar model was able to learn to anticipate (predict) conditioned responses with accurate timing and success rate, demonstrating fast acquisition, memory stabilization, rapid extinction, and faster reacquisition as in EBCC in humans. The firing of Purkinje cells (PCs) and deep cerebellar nuclei (DCN) changed during learning under the control of synaptic plasticity, which evolved at different rates, with a faster acquisition in the cerebellar cortex than in DCN synapses. Eventually, a reduced PC activity released DCN discharge just after the CS, precisely anticipating the US and causing the eyeblink. Moreover, a specific alteration in cortical plasticity explained the EBCC changes induced by cerebellar TMS in humans. In this paper, for the first time, it is shown how closed-loop simulations, using detailed cerebellar microcircuit models, can be successfully used to fit real experimental data sets. Thus, the changes of the

  14. Phylogenetic study of Class Armophorea (Alveolata, Ciliophora based on 18S-rDNA data

    Directory of Open Access Journals (Sweden)

    Thiago da Silva Paiva

    2013-01-01

    Full Text Available The 18S rDNA phylogeny of Class Armophorea, a group of anaerobic ciliates, is proposed based on an analysis of 44 sequences (out of 195 retrieved from the NCBI/GenBank database. Emphasis was placed on the use of two nucleotide alignment criteria that involved variation in the gap-opening and gap-extension parameters and the use of rRNA secondary structure to orientate multiple-alignment. A sensitivity analysis of 76 data sets was run to assess the effect of variations in indel parameters on tree topologies. Bayesian inference, maximum likelihood and maximum parsimony phylogenetic analyses were used to explore how different analytic frameworks influenced the resulting hypotheses. A sensitivity analysis revealed that the relationships among higher taxa of the Intramacronucleata were dependent upon how indels were determined during multiple-alignment of nucleotides. The phylogenetic analyses rejected the monophyly of the Armophorea most of the time and consistently indicated that the Metopidae and Nyctotheridae were related to the Litostomatea. There was no consensus on the placement of the Caenomorphidae, which could be a sister group of the Metopidae + Nyctorheridae, or could have diverged at the base of the Spirotrichea branch or the Intramacronucleata tree.

  15. Analysis of trophic interactions reveals highly plastic response to climate change in a tri-trophic High-Arctic ecosystem

    DEFF Research Database (Denmark)

    Mortensen, Lars O.; Schmidt, Niels Martin; Hoye, Toke T.

    2016-01-01

    As a response to current climate changes, individual species have changed various biological traits, illustrating an inherent phenotypic plasticity. However, as species are embedded in an ecological network characterised by multiple consumer-resource interactions, ecological mismatches are likely...... to arise when interacting species do not respond homogeneously. The approach of biological networks analysis calls for the use of structural equation modelling (SEM), a multidimensional analytical setup that has proven particularly useful for analysing multiple interactions across trophic levels. Here we...

  16. Dual RNA-seq reveals no plastic transcriptional response of the coccidian parasite Eimeria falciformis to host immune defenses.

    Science.gov (United States)

    Ehret, Totta; Spork, Simone; Dieterich, Christoph; Lucius, Richard; Heitlinger, Emanuel

    2017-09-05

    Parasites can either respond to differences in immune defenses that exist between individual hosts plastically or, alternatively, follow a genetically canalized ("hard wired") program of infection. Assuming that large-scale functional plasticity would be discernible in the parasite transcriptome we have performed a dual RNA-seq study of the lifecycle of Eimeria falciformis using infected mice with different immune status as models for coccidian infections. We compared parasite and host transcriptomes (dual transcriptome) between naïve and challenge infected mice, as well as between immune competent and immune deficient ones. Mice with different immune competence show transcriptional differences as well as differences in parasite reproduction (oocyst shedding). Broad gene categories represented by differently abundant host genes indicate enrichments for immune reaction and tissue repair functions. More specifically, TGF-beta, EGF, TNF and IL-1 and IL-6 are examples of functional annotations represented differently depending on host immune status. Much in contrast, parasite transcriptomes were neither different between Coccidia isolated from immune competent and immune deficient mice, nor between those harvested from naïve and challenge infected mice. Instead, parasite transcriptomes have distinct profiles early and late in infection, characterized largely by biosynthesis or motility associated functional gene groups, respectively. Extracellular sporozoite and oocyst stages showed distinct transcriptional profiles and sporozoite transcriptomes were found enriched for species specific genes and likely pathogenicity factors. We propose that the niche and host-specific parasite E. falciformis uses a genetically canalized program of infection. This program is likely fixed in an evolutionary process rather than employing phenotypic plasticity to interact with its host. This in turn might limit the potential of the parasite to adapt to new host species or niches, forcing

  17. A Combined Optogenetic-Knockdown Strategy Reveals a Major Role of Tomosyn in Mossy Fiber Synaptic Plasticity

    Directory of Open Access Journals (Sweden)

    Yoav Ben-Simon

    2015-07-01

    Full Text Available Neurotransmitter release probability (Pr largely determines the dynamic properties of synapses. While much is known about the role of presynaptic proteins in transmitter release, their specific contribution to synaptic plasticity is unclear. One such protein, tomosyn, is believed to reduce Pr by interfering with the SNARE complex formation. Tomosyn is enriched at hippocampal mossy fiber-to-CA3 pyramidal cell synapses (MF-CA3, which characteristically exhibit low Pr, strong synaptic facilitation, and pre-synaptic protein kinase A (PKA-dependent long-term potentiation (LTP. To evaluate tomosyn’s role in MF-CA3 function, we used a combined knockdown (KD-optogenetic strategy whereby presynaptic neurons with reduced tomosyn levels were selectively activated by light. Using this approach in mouse hippocampal slices, we found that facilitation, LTP, and PKA-induced potentiation were significantly impaired at tomosyn-deficient synapses. These findings not only indicate that tomosyn is a key regulator of MF-CA3 plasticity but also highlight the power of a combined KD-optogenetic approach to determine the role of presynaptic proteins.

  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. Correlative STED and Atomic Force Microscopy on Live Astrocytes Reveals Plasticity of Cytoskeletal Structure and Membrane Physical Properties during Polarized Migration

    Directory of Open Access Journals (Sweden)

    Nathalie Rouach

    2017-04-01

    Full Text Available The plasticity of the cytoskeleton architecture and membrane properties is important for the establishment of cell polarity, adhesion and migration. Here, we present a method which combines stimulated emission depletion (STED super-resolution imaging and atomic force microscopy (AFM to correlate cytoskeletal structural information with membrane physical properties in live astrocytes. Using STED compatible dyes for live cell imaging of the cytoskeleton, and simultaneously mapping the cell surface topology with AFM, we obtain unprecedented detail of highly organized networks of actin and microtubules in astrocytes. Combining mechanical data from AFM with optical imaging of actin and tubulin further reveals links between cytoskeleton organization and membrane properties. Using this methodology we illustrate that scratch-induced migration induces cytoskeleton remodeling. The latter is caused by a polarization of actin and microtubule elements within astroglial cell processes, which correlates strongly with changes in cell stiffness. The method opens new avenues for the dynamic probing of the membrane structural and functional plasticity of living brain cells. It is a powerful tool for providing new insights into mechanisms of cell structural remodeling during physiological or pathological processes, such as brain development or tumorigenesis.

  20. Clonal analysis of Notch1-expressing cells reveals the existence of unipotent stem cells that retain long-term plasticity in the embryonic mammary gland.

    Science.gov (United States)

    Lilja, Anna M; Rodilla, Veronica; Huyghe, Mathilde; Hannezo, Edouard; Landragin, Camille; Renaud, Olivier; Leroy, Olivier; Rulands, Steffen; Simons, Benjamin D; Fre, Silvia

    2018-06-01

    Recent lineage tracing studies have revealed that mammary gland homeostasis relies on unipotent stem cells. However, whether and when lineage restriction occurs during embryonic mammary development, and which signals orchestrate cell fate specification, remain unknown. Using a combination of in vivo clonal analysis with whole mount immunofluorescence and mathematical modelling of clonal dynamics, we found that embryonic multipotent mammary cells become lineage-restricted surprisingly early in development, with evidence for unipotency as early as E12.5 and no statistically discernable bipotency after E15.5. To gain insights into the mechanisms governing the switch from multipotency to unipotency, we used gain-of-function Notch1 mice and demonstrated that Notch activation cell autonomously dictates luminal cell fate specification to both embryonic and basally committed mammary cells. These functional studies have important implications for understanding the signals underlying cell plasticity and serve to clarify how reactivation of embryonic programs in adult cells can lead to cancer.

  1. Deep-water feeding and behavioral plasticity in Manta birostris revealed by archival tags and submersible observations.

    Science.gov (United States)

    Stewart, Joshua D; Hoyos-Padilla, Edgar Mauricio; Kumli, Katherine R; Rubin, Robert D

    2016-10-01

    Foraging drives many fundamental aspects of ecology, and an understanding of foraging behavior aids in the conservation of threatened species by identifying critical habitats and spatial patterns relevant to management. The world's largest ray, the oceanic manta (Manta birostris) is poorly studied and threatened globally by targeted fisheries and incidental capture. Very little information is available on the natural history, ecology and behavior of the species, complicating management efforts. This study provides the first data on the diving behavior of the species based on data returned from six tagged individuals, and an opportunistic observation from a submersible of a manta foraging at depth. Pop-off archival satellite tags deployed on mantas at the Revillagigedo Archipelago, Mexico recorded seasonal shifts in diving behavior, likely related to changes in the location and availability of zooplankton prey. Across seasons, mantas spent a large proportion of their time centered around the upper limit of the thermocline, where zooplankton often aggregate. Tag data reveal a gradual activity shift from surface waters to 100-150m across the tagging period, possibly indicating a change in foraging behavior from targeting surface-associated zooplankton to vertical migrators. The depth ranges accessed by mantas in this study carry variable bycatch risks from different fishing gear types. Consequently, region-specific data on diving behavior can help inform local management strategies that reduce or mitigate bycatch of this vulnerable species. Copyright © 2016 Elsevier GmbH. All rights reserved.

  2. Extensive genomic plasticity in Pseudomonas aeruginosa revealed by identification and distribution studies of novel genes among clinical isolates.

    Science.gov (United States)

    Shen, Kai; Sayeed, Sameera; Antalis, Patricia; Gladitz, John; Ahmed, Azad; Dice, Bethany; Janto, Benjamin; Dopico, Richard; Keefe, Randy; Hayes, Jay; Johnson, Sandra; Yu, Sujun; Ehrlich, Nathan; Jocz, Jennifer; Kropp, Laura; Wong, Ray; Wadowsky, Robert M; Slifkin, Malcolm; Preston, Robert A; Erdos, Geza; Post, J Christopher; Ehrlich, Garth D; Hu, Fen Z

    2006-09-01

    The distributed genome hypothesis (DGH) states that each strain within a bacterial species receives a unique distribution of genes from a population-based supragenome that is many times larger than the genome of any given strain. The observations that natural infecting populations are often polyclonal and that most chronic bacterial pathogens have highly developed mechanisms for horizontal gene transfer suggested the DGH and provided the means and the mechanisms to explain how chronic infections persist in the face of a mammalian host's adaptive defense mechanisms. Having previously established the validity of the DGH for obligate pathogens, we wished to evaluate its applicability to an opportunistic bacterial pathogen. This was accomplished by construction and analysis of a highly redundant pooled genomic library containing approximately 216,000 functional clones that was constructed from 12 low-passage clinical isolates of Pseudomonas aeruginosa, 6 otorrheic isolates and 6 from other body sites. Sequence analysis of 3,214 randomly picked clones (mean insert size, approximately 1.4 kb) from this library demonstrated that 348 (10.8%) of the clones were unique with respect to all genomic sequences of the P. aeruginosa prototype strain, PAO1. Hypothetical translations of the open reading frames within these unique sequences demonstrated protein homologies to a number of bacterial virulence factors and other proteins not previously identified in P. aeruginosa. PCR and reverse transcription-PCR-based assays were performed to analyze the distribution and expression patterns of a 70-open reading frame subset of these sequences among 11 of the clinical strains. These sequences were unevenly distributed among the clinical isolates, with nearly half (34/70) of the novel sequences being present in only one or two of the individual strains. Expression profiling revealed that a vast majority of these sequences are expressed, strongly suggesting they encode functional proteins.

  3. Genomic Programming of Human Neonatal Dendritic Cells in Congenital Systemic and In Vitro Cytomegalovirus Infection Reveal Plastic and Robust Immune Pathway Biology Responses

    Directory of Open Access Journals (Sweden)

    Widad Dantoft

    2017-09-01

    Full Text Available Neonates and especially premature infants are highly susceptible to infection but still can have a remarkable resilience that is poorly understood. The view that neonates have an incomplete or deficient immune system is changing. Human neonatal studies are challenging, and elucidating host protective responses and underlying cognate pathway biology, in the context of viral infection in early life, remains to be fully explored. In both resource rich and poor settings, human cytomegalovirus (HCMV is the most common cause of congenital infection. By using unbiased systems analyses of transcriptomic resources for HCMV neonatal infection, we find the systemic response of a preterm congenital HCMV infection, involves a focused IFN regulatory response associated with dendritic cells. Further analysis of transcriptional-programming of neonatal dendritic cells in response to HCMV infection in culture revealed an early dominant IFN-chemokine regulatory subnetworks, and at later times the plasticity of pathways implicated in cell-cycle control and lipid metabolism. Further, we identify previously unknown suppressed networks associated with infection, including a select group of GPCRs. Functional siRNA viral growth screen targeting 516-GPCRs and subsequent validation identified novel GPCR-dependent antiviral (ADORA1 and proviral (GPR146, RGS16, PTAFR, SCTR, GPR84, GPR85, NMUR2, FZ10, RDS, CCL17, and SORT1 roles. By contrast a gene family cluster of protocadherins is significantly differentially induced in neonatal cells, suggestive of possible immunomodulatory roles. Unexpectedly, programming responses of adult and neonatal dendritic cells, upon HCMV infection, demonstrated comparable quantitative and qualitative responses showing that functionally, neonatal dendritic cell are not overly compromised. However, a delay in responses of neonatal cells for IFN subnetworks in comparison with adult-derived cells are notable, suggestive of subtle plasticity

  4. Genomic Programming of Human Neonatal Dendritic Cells in Congenital Systemic and In Vitro Cytomegalovirus Infection Reveal Plastic and Robust Immune Pathway Biology Responses.

    Science.gov (United States)

    Dantoft, Widad; Martínez-Vicente, Pablo; Jafali, James; Pérez-Martínez, Lara; Martin, Kim; Kotzamanis, Konstantinos; Craigon, Marie; Auer, Manfred; Young, Neil T; Walsh, Paul; Marchant, Arnaud; Angulo, Ana; Forster, Thorsten; Ghazal, Peter

    2017-01-01

    Neonates and especially premature infants are highly susceptible to infection but still can have a remarkable resilience that is poorly understood. The view that neonates have an incomplete or deficient immune system is changing. Human neonatal studies are challenging, and elucidating host protective responses and underlying cognate pathway biology, in the context of viral infection in early life, remains to be fully explored. In both resource rich and poor settings, human cytomegalovirus (HCMV) is the most common cause of congenital infection. By using unbiased systems analyses of transcriptomic resources for HCMV neonatal infection, we find the systemic response of a preterm congenital HCMV infection, involves a focused IFN regulatory response associated with dendritic cells. Further analysis of transcriptional-programming of neonatal dendritic cells in response to HCMV infection in culture revealed an early dominant IFN-chemokine regulatory subnetworks, and at later times the plasticity of pathways implicated in cell-cycle control and lipid metabolism. Further, we identify previously unknown suppressed networks associated with infection, including a select group of GPCRs. Functional siRNA viral growth screen targeting 516-GPCRs and subsequent validation identified novel GPCR-dependent antiviral (ADORA1) and proviral (GPR146, RGS16, PTAFR, SCTR, GPR84, GPR85, NMUR2, FZ10, RDS, CCL17, and SORT1) roles. By contrast a gene family cluster of protocadherins is significantly differentially induced in neonatal cells, suggestive of possible immunomodulatory roles. Unexpectedly, programming responses of adult and neonatal dendritic cells, upon HCMV infection, demonstrated comparable quantitative and qualitative responses showing that functionally, neonatal dendritic cell are not overly compromised. However, a delay in responses of neonatal cells for IFN subnetworks in comparison with adult-derived cells are notable, suggestive of subtle plasticity differences. These

  5. miR-132/212 knockout mice reveal roles for these miRNAs in regulating cortical synaptic transmission and plasticity.

    Directory of Open Access Journals (Sweden)

    Judit Remenyi

    Full Text Available miR-132 and miR-212 are two closely related miRNAs encoded in the same intron of a small non-coding gene, which have been suggested to play roles in both immune and neuronal function. We describe here the generation and initial characterisation of a miR-132/212 double knockout mouse. These mice were viable and fertile with no overt adverse phenotype. Analysis of innate immune responses, including TLR-induced cytokine production and IFNβ induction in response to viral infection of primary fibroblasts did not reveal any phenotype in the knockouts. In contrast, the loss of miR-132 and miR-212, while not overtly affecting neuronal morphology, did affect synaptic function. In both hippocampal and neocortical slices miR-132/212 knockout reduced basal synaptic transmission, without affecting paired-pulse facilitation. Hippocampal long-term potentiation (LTP induced by tetanic stimulation was not affected by miR-132/212 deletion, whilst theta burst LTP was enhanced. In contrast, neocortical theta burst-induced LTP was inhibited by loss of miR-132/212. Together these results indicate that miR-132 and/or miR-212 play a significant role in synaptic function, possibly by regulating the number of postsynaptic AMPA receptors under basal conditions and during activity-dependent synaptic plasticity.

  6. 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 " ...

  7. Lack of mitochondrial MutS homolog 1 in Toxoplasma gondii disrupts maintenance and fidelity of mitochondrial DNA and reveals metabolic plasticity.

    Directory of Open Access Journals (Sweden)

    Tamila Garbuz

    , reveals a novel mechanism for atovaquone resistance, and exposes the physiological plasticity of this important human pathogen.

  8. 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

  9. Life-cycle, ultrastructure, and phylogeny of Parvilucifera corolla sp. nov. (Alveolata, Perkinsozoa), a parasitoid of dinoflagellates.

    Science.gov (United States)

    Reñé, Albert; Alacid, Elisabet; Figueroa, Rosa Isabel; Rodríguez, Francisco; Garcés, Esther

    2017-04-01

    Recent studies of marine protists have revealed parasites to be key components of marine communities. Here we describe a new species of the parasitoid genus Parvilucifera that was observed infecting the dinoflagellate Durinskia baltica in salt marshes of the Catalan coast (NW Mediterranean). In parallel, the same species was detected after the incubation of seawater from the Canary Islands (Lanzarote, NE Atlantic). The successful isolation of strains from both localities allowed description of the life cycle, ultrastructure, and phylogeny of the species. Its infection mechanism consists of a free-living zoospore that penetrates a dinoflagellate cell. The resulting trophont gradually degrades the dinoflagellate cytoplasm while growing in size. Once the host is consumed, schizogony of the parasitoid yields a sporocyte. After cytokinesis is complete, the newly formed zoospores are released into the environment and are ready to infect new host cells. A distinguishing feature of the species is the radial arrangement of its zoospores around the central area of the sporocyte during their formation. The species shows a close morphological similarity with other species of the genus, including P. infectans, P. sinerae, and P. rostrata. Copyright © 2016 Elsevier GmbH. All rights reserved.

  10. Cortical and Subcortical Structural Plasticity Associated with the Glioma Volumes in Patients with Cerebral Gliomas Revealed by Surface-Based Morphometry

    Directory of Open Access Journals (Sweden)

    Jinping Xu

    2017-06-01

    Full Text Available Postlesional plasticity has been identified in patients with cerebral gliomas by inducing a large functional reshaping of brain networks. Although numerous non-invasive functional neuroimaging methods have extensively investigated the mechanisms of this functional redistribution in patients with cerebral gliomas, little effort has been made to investigate the structural plasticity of cortical and subcortical structures associated with the glioma volume. In this study, we aimed to investigate whether the contralateral cortical and subcortical structures are able to actively reorganize by themselves in these patients. The compensation mechanism following contralateral cortical and subcortical structural plasticity is considered. We adopted the surface-based morphometry to investigate the difference of cortical and subcortical gray matter (GM volumes in a cohort of 14 healthy controls and 13 patients with left-hemisphere cerebral gliomas [including 1 patients with World Health Organization (WHO I, 8 WHO II, and 4 WHO III]. The glioma volume ranges from 5.1633 to 208.165 cm2. Compared to healthy controls, we found significantly increased GM volume of the right cuneus and the left thalamus, as well as a trend toward enlargement in the right globus pallidus in patients with cerebral gliomas. Moreover, the GM volumes of these regions were positively correlated with the glioma volumes of the patients. These results provide evidence of cortical and subcortical enlargement, suggesting the usefulness of surface-based morphometry to investigate the structural plasticity. Moreover, the structural plasticity might be acted as the compensation mechanism to better fulfill its functions in patients with cerebral gliomas as the gliomas get larger.

  11. Crystal structures reveal metal-binding plasticity at the metallo-β-lactamase active site of PqqB from Pseudomonas putida

    Energy Technology Data Exchange (ETDEWEB)

    Tu, Xiongying; Latham, John A.; Klema, Valerie J.; Evans III, Robert L.; Li, Chao; Klinman, Judith P.; Wilmot, Carrie M. (UMM); (UCB)

    2017-08-19

    PqqB is an enzyme involved in the biosynthesis of pyrroloquinoline quinone and a distal member of the metallo-β-lactamase (MBL) superfamily. PqqB lacks two residues in the conserved signature motif HxHxDH that makes up the key metal-chelating elements that can bind up to two metal ions at the active site of MBLs and other members of its superfamily. Here, we report crystal structures of PqqB bound to Mn2+, Mg2+, Cu2+, and Zn2+. These structures demonstrate that PqqB can still bind metal ions at the canonical MBL active site. The fact that PqqB can adapt its side chains to chelate a wide spectrum of metal ions with different coordination features on a uniform main chain scaffold demonstrates its metal-binding plasticity. This plasticity may provide insights into the structural basis of promiscuous activities found in ensembles of metal complexes within this superfamily. Furthermore, PqqB belongs to a small subclass of MBLs that contain an additional CxCxxC motif that binds a structural Zn2+. Our data support a key role for this motif in dimerization.

  12. 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.)

  13. PLASTIC SURGERY

    African Journals Online (AJOL)

    Department of Plastic and Reconstructive Surgery Sefako Makgatho Health Science University, ... We report on a pilot study on the use of a circumareolar excision and the use of .... and 1 gynecomastia patient) requested reduction in NAC size.

  14. 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.

  15. Computational materials science: Nanoscale plasticity

    DEFF Research Database (Denmark)

    Jacobsen, Karsten Wedel; Schiøtz, Jakob

    2002-01-01

    How does plastic deformation of polycrystalline materials with grain sizes less than 100 nm look at the atomic scale? A large-scale molecular dynamics simulation of nanocrystalline alluminium reveals some surprising behaviour.......How does plastic deformation of polycrystalline materials with grain sizes less than 100 nm look at the atomic scale? A large-scale molecular dynamics simulation of nanocrystalline alluminium reveals some surprising behaviour....

  16. 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...

  17. 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

  18. 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.

  19. 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.

  20. 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.

  1. Pervasive plastic

    Science.gov (United States)

    2018-05-01

    Human manipulation of hydrocarbons — as fuel and raw materials for modern society — has changed our world and the indelible imprint we will leave in the rock record. Plastics alone have permeated our lives and every corner of our planet.

  2. 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...

  3. Plastic deformation

    NARCIS (Netherlands)

    Sitter, de L.U.

    1937-01-01

    § 1. Plastic deformation of solid matter under high confining pressures has been insufficiently studied. Jeffreys 1) devotes a few paragraphs to deformation of solid matter as a preface to his chapter on the isostasy problem. He distinguishes two properties of solid matter with regard to its

  4. Conformational Plasticity of the Cell-Penetrating Peptide SAP As Revealed by Solid-State 19F-NMR and Circular Dichroism Spectroscopies.

    Science.gov (United States)

    Afonin, Sergii; Kubyshkin, Vladimir; Mykhailiuk, Pavel K; Komarov, Igor V; Ulrich, Anne S

    2017-07-13

    The cell-penetrating peptide SAP, which was designed as an amphipathic poly-l-proline helix II (PPII), was suggested to self-assemble into regular fibrils that are relevant for its internalization. Herein we have analyzed the structure of SAP in the membrane-bound state by solid-state 19 F-NMR, which revealed other structural states, in addition to the expected surface-aligned PPII. Trifluoromethyl-bicyclopentyl-glycine (CF 3 -Bpg) and two rigid isomers of trifluoromethyl-4,5-methanoprolines (CF 3 -MePro) were used as labels for 19 F-NMR analysis. The equilibria between different conformations of SAP were studied and were found to be shifted by the substituents at Pro-11. Synchrotron-CD results suggested that substituting Pro-11 by CF 3 -MePro governed the coil-to-PPII equilibrium in solution and in the presence of a lipid bilayer. Using CD and 19 F-NMR, we examined the slow kinetics of the association of SAP with membranes and the dependence of the SAP conformational dynamics on the lipid composition. The peptide did not bind to lipids in the solid ordered phase and aggregated only in the liquid ordered "raft"-like bilayers. Self-association could not be detected in solution or in the presence of liquid disordered membranes. Surface-bound amphipathic SAP in a nonaggregated state was structured as a mixture of nonideal extended conformations reflecting the equilibrium already present in solution, i.e., before binding to the membrane.

  5. Stable isotopes (δ13C, δ15N combined with conventional dietary approaches reveal plasticity in central-place foraging behaviour of little penguins (Eudyptula minor

    Directory of Open Access Journals (Sweden)

    Andre eChiaradia

    2016-01-01

    reveal an otherwise intractable ecological issue of different constrains of being a central-place forager, such as the little penguin, which could be applied to other marine species.

  6. Grain Interactions in Crystal Plasticity

    International Nuclear Information System (INIS)

    Boyle, K.P.; Curtin, W.A.

    2005-01-01

    The plastic response of a sheet metal is governed by the collective response of the underlying grains. Intragranular plasticity depends on intrinsic variables such as crystallographic orientation and on extrinsic variables such as grain interactions; however, the role of the latter is not well understood. A finite element crystal plasticity formulation is used to investigate the importance of grain interactions on intragranular plastic deformation in initially untextured polycrystalline aggregates. A statistical analysis reveals that grain interactions are of equal (or more) importance for determining the average intragranular deviations from the applied strain as compared to the orientation of the grain itself. Furthermore, the influence of the surrounding grains is found to extend past nearest neighbor interactions. It is concluded that the stochastic nature of the mesoscale environment must be considered for a proper understanding of the plastic response of sheet metals at the grain-scale

  7. 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) ...

  8. Water Vapor Permeation in Plastics

    Energy Technology Data Exchange (ETDEWEB)

    Keller, Paul E. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Kouzes, Richard T. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2017-01-01

    Polyvinyl toluene (PVT) and polystyrene (PS) (referred to as “plastic scintillator”) are used for gamma ray detectors. A significant decrease in radiation detection performance has been observed in some PVT-based gamma-ray detectors in systems in outdoor environments as they age. Recent studies have revealed that plastic scintillator can undergo an environmentally related material degradation that adversely affects gamma ray detection performance under certain conditions and histories. A significant decrease in sensitivity has been seen in some gamma-ray detectors in some systems as they age. The degradation of sensitivity of plastic scintillator over time is due to a variety of factors, and the term “aging” is used to encompass all factors. Some plastic scintillator samples show no aging effects (no significant change in sensitivity over more than 10 years), while others show severe aging (significant change in sensitivity in less than 5 years). Aging effects arise from weather (variations in heat and humidity), chemical exposure, mechanical stress, light exposure, and loss of volatile components. The damage produced by these various causes can be cumulative, causing observable damage to increase over time. Damage may be reversible up to some point, but becomes permanent under some conditions. The objective of this report is to document the phenomenon of permeability of plastic scintillator to water vapor and to derive the relationship between time, temperature, humidity and degree of water penetration in plastic. Several conclusions are documented about the properties of water permeability of plastic scintillator.

  9. Plastic scintillator

    International Nuclear Information System (INIS)

    Andreeshchev, E.A.; Kilin, S.F.; Kavyrzina, K.A.

    1978-01-01

    A plastic scintillator for ionizing radiation detectors with high time resolution is suggested. To decrease the scintillation pulse width and to maintain a high light yield, the 4 1 , 4 5 -dibromo-2 1 , 2 5 , 5 1 , 5 5 -tetramethyl-n-quinquiphenyl (Br 2 Me 4 Ph) in combination with n-terphenyl (Ph 3 ) or 2, 5-diphenyloxadiazol-1, 3, 4 (PPD) is used as a luminescent addition. Taking into consideration the results of a special study, it is shown, that the following ratio of ingradients is the optimum one: 3-4 mass% Ph 3 or 4-7 mas% PPD + 2-5 mass% Br 2 Me 4 Ph + + polymeric base. The suggested scintillator on the basis of polystyrene has the light yield of 0.23-0.26 arbitrary units and the scintillation pulse duration at half-height is 0.74-0.84 ns

  10. 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.

  11. Seasonal diversity of planktonic protists in Southwestern Alberta rivers over a 1-year period as revealed by terminal restriction fragment length polymorphism and 18S rRNA gene library analyses.

    Science.gov (United States)

    Thomas, Matthew C; Selinger, L Brent; Inglis, G Douglas

    2012-08-01

    The temporal dynamics of planktonic protists in river water have received limited attention despite their ecological significance and recent studies linking phagotrophic protists to the persistence of human-pathogenic bacteria. Using molecular-based techniques targeting the 18S rRNA gene, we studied the seasonal diversity of planktonic protists in Southwestern Alberta rivers (Oldman River Basin) over a 1-year period. Nonmetric multidimensional scaling analysis of terminal restriction fragment length polymorphism (T-RFLP) data revealed distinct shifts in protistan community profiles that corresponded to season rather than geographical location. Community structures were examined by using clone library analysis; HaeIII restriction profiles of 18S rRNA gene amplicons were used to remove prevalent solanaceous plant clones prior to sequencing. Sanger sequencing of the V1-to-V3 region of the 18S rRNA gene libraries from spring, summer, fall, and winter supported the T-RFLP results and showed marked seasonal differences in the protistan community structure. The spring library was dominated by Chloroplastidae (29.8%), Centrohelida (28.1%), and Alveolata (25.5%), while the summer and fall libraries contained primarily fungal clones (83.0% and 88.0%, respectively). Alveolata (35.6%), Euglenozoa (24.4%), Chloroplastida (15.6%), and Fungi (15.6%) dominated the winter library. These data demonstrate that planktonic protists, including protozoa, are abundant in river water in Southwestern Alberta and that conspicuous seasonal shifts occur in the community structure.

  12. 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...

  13. Seabirds, gyres and global trends in plastic pollution

    International Nuclear Information System (INIS)

    Franeker, Jan A. van; Law, Kara Lavender

    2015-01-01

    Fulmars are effective biological indicators of the abundance of floating plastic marine debris. Long-term data reveal high plastic abundance in the southern North Sea, gradually decreasing to the north at increasing distance from population centres, with lowest levels in high-arctic waters. Since the 1980s, pre-production plastic pellets in North Sea fulmars have decreased by ∼75%, while user plastics varied without a strong overall change. Similar trends were found in net-collected floating plastic debris in the North Atlantic subtropical gyre, with a ∼75% decrease in plastic pellets and no obvious trend in user plastic. The decreases in pellets suggest that changes in litter input are rapidly visible in the environment not only close to presumed sources, but also far from land. Floating plastic debris is rapidly “lost” from the ocean surface to other as-yet undetermined sinks in the marine environment. - Highlights: • Seabirds are effective biological monitors of floating plastic marine debris. • Plastics in fulmar stomachs and in the North Atlantic gyre show similar trends. • Pre-production plastic pellets show strong decreases in fulmars and in the gyre. • These data show that floating plastics rapidly disappear from the ocean surface. - Long term studies give evidence that reduced input of plastic debris into the ocean becomes rapidly visible. Floating plastics disappear to as-yet undetermined sinks

  14. 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)

  15. DESIGNERS’ KNOWLEDGE IN PLASTICS

    DEFF Research Database (Denmark)

    Eriksen, Kaare

    2013-01-01

    The Industrial designers’ knowledge in plastics materials and manufacturing principles of polymer products is very important for the innovative strength of the industry, according to a group of Danish plastics manufacturers, design students and practicing industrial designers. These three groups ...

  16. Processing of plastic track detectors

    International Nuclear Information System (INIS)

    Somogyi, G.

    1977-01-01

    A survey of some actual problems of the track processing methods available at this time for plastics is presented. In the case of the conventional chemical track-etching technique, mainly the etching situations related to detector geometry, and the relationship between registration sensitivity and the etching parameters are considered. Special attention is paid to the behaviour of track-revealing by means of electrochemical etching. Finally, some properties of a promising new track processing method based on graft polymerization are discussed. (author)

  17. Processing of plastic track detectors

    International Nuclear Information System (INIS)

    Somogyi, G.

    1976-01-01

    A survey of some actual problems of the track processing methods available at this time for plastics is presented. In the case of the conventional chemical track etching technique mainly the etching situations related to detector geometry and the relationship of registration sensitivity and the etching parameters are considered. A special attention is paid to the behaviour of track revealing by means of electrochemical etching. Finally, some properties of a promising new track processing method based on graft polymerization is discussed. (orig.) [de

  18. 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....

  19. 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.

  20. 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.

  1. 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...

  2. Photoperiodic differences in a forebrain nucleus involved in vocal plasticity: enkephalin immunoreactivity reveals volumetric variation in song nucleus lMAN but not NIf in male European starlings (Sturnus vulgaris).

    Science.gov (United States)

    Stevenson, Tyler J; Ball, Gregory F

    2010-09-15

    Seasonal variation in the volume of various song control nuclei in many passerine species remains one of the best examples of naturally occurring adult neuroplasticity among vertebrates. The lateral portion of the magnocellular nucleus of the anterior nidopallium (lMAN) is a song nucleus that is important for song learning and seems to be critical for inducing variability in the song structure that is later pruned via a feedback process to produce adult crystallized song. To date, lMAN has not been shown to exhibit seasonal changes in volume, probably because it is difficult to resolve the boundaries of lMAN when employing histological methods based on Nissl staining. Here, lMAN(core) volumes were examined in intact photostimulated (i.e., breeding), castrated photostimulated and photorefractory (i.e., nonbreeding) male starlings (Sturnus vulgaris) to investigate the degree of seasonal variation in brain morphology. We present data demonstrating that the volumes of the total MAN and lMAN(core) delineated by enkephalin immunoreactivity are greater in photostimulated male starlings as compared to photorefractory males. Moreover, two other regions associated with the song system that have not been investigated previously in the context of seasonal plasticity namely (i) the medial portion of MAN (mMAN), and (ii) the nucleus interfacialis (NIf) did not display significant volumetric variation. We propose that greater lMAN(core) volumes are associated with the increase in vocal plasticity that is generally observed prior to production of stereotyped song.

  3. 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...

  4. 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.

  5. 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

  6. 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.

  7. 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.

  8. 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...

  9. Plasticity: modeling & computation

    National Research Council Canada - National Science Library

    Borja, Ronaldo Israel

    2013-01-01

    .... "Plasticity Modeling & Computation" is a textbook written specifically for students who want to learn the theoretical, mathematical, and computational aspects of inelastic deformation in solids...

  10. 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.

  11. 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.

  12. Genetic Regulation of Phenotypic Plasticity and Canalisation in Yeast Growth.

    Directory of Open Access Journals (Sweden)

    Anupama Yadav

    Full Text Available The ability of a genotype to show diverse phenotypes in different environments is called phenotypic plasticity. Phenotypic plasticity helps populations to evade extinctions in novel environments, facilitates adaptation and fuels evolution. However, most studies focus on understanding the genetic basis of phenotypic regulation in specific environments. As a result, while it's evolutionary relevance is well established, genetic mechanisms regulating phenotypic plasticity and their overlap with the environment specific regulators is not well understood. Saccharomyces cerevisiae is highly sensitive to the environment, which acts as not just external stimulus but also as signalling cue for this unicellular, sessile organism. We used a previously published dataset of a biparental yeast population grown in 34 diverse environments and mapped genetic loci regulating variation in phenotypic plasticity, plasticity QTL, and compared them with environment-specific QTL. Plasticity QTL is one whose one allele exhibits high plasticity whereas the other shows a relatively canalised behaviour. We mapped phenotypic plasticity using two parameters-environmental variance, an environmental order-independent parameter and reaction norm (slope, an environmental order-dependent parameter. Our results show a partial overlap between pleiotropic QTL and plasticity QTL such that while some plasticity QTL are also pleiotropic, others have a significant effect on phenotypic plasticity without being significant in any environment independently. Furthermore, while some plasticity QTL are revealed only in specific environmental orders, we identify large effect plasticity QTL, which are order-independent such that whatever the order of the environments, one allele is always plastic and the other is canalised. Finally, we show that the environments can be divided into two categories based on the phenotypic diversity of the population within them and the two categories have

  13. History of plastic surgery: Art, philosophy, and rhinoplasty.

    Science.gov (United States)

    Macionis, Valdas

    2018-03-23

    The 200th anniversary of K. F. Graefe's "Rhinoplasty," E. Zeis' naming of the specialty of plastic surgery in 1838, and the continuing discussion on what is plastic surgery have prompted this historical-conceptual review with a semantic insight into the meaning of the word "plastic." A literature search has revealed that this term contains dual aspects: artistic and philosophical. The progressive development of these two connotations can be traced from their origin in the ceramics and the myths of ancient Greeks to their metamorphoses in fine arts, science, and philosophy of plasticity of the modern day. Although the names of plastic procedures and the title of the specialty carry both the artistic and philosophical features, the philosophical notion is less evident. This article underlines the importance of etymology in the interpretation of the concept of plastic surgery. Copyright © 2018 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved.

  14. Venous thromboembolism prophylaxis in plastic surgery

    DEFF Research Database (Denmark)

    Nielsen, Lea Juul; Matzen, Steen H

    2017-01-01

    BACKGROUND: Venous thromboembolism is a well-documented complication of surgery, including plastic surgery. However, few consensus guidelines on thromboembolism prophylaxis exist in plastic surgery and, thus, the different approaches in the public as well as the private clinics in Denmark were...... investigated using a web-based survey. METHODS: Forty-two clinics were contacted and 45% responded. RESULTS: The collected data reveals a lack of consensus in plastic surgery in Denmark, not only regarding the use of mechanical and chemical prophylaxis, but also which type of prophylaxis to apply, the duration...... of prophylaxis, and how to risk stratify the patients. CONCLUSION: The development of a guideline, based on plastic surgical data, using a validated risk assessment model, which combines the surgical risk with the patient related risk and recommends guidelines for mechanical as well as chemoprophylaxis...

  15. Linking Scales in Plastic Deformation and Fracture

    DEFF Research Database (Denmark)

    Martinez-Paneda, Emilio; Niordson, Christian Frithiof; S. Deshpande, Vikram

    2017-01-01

    We investigate crack growth initiation and subsequent resistance in metallic materials by means of an implicit multi-scale approach. Strain gradient plasticity is employed to model the mechanical response of the solid so as to incorporate the role of geometrically necessary dislocations (GNDs......) and accurately capture plasticity at the small scales involved in crack tip deformation. The response ahead of the crack is described by means of a traction-separation law, which is characterized by the cohesive strength and the fracture energy. Results reveal that large gradients of plastic strain accumulatein...... the vicinity of the crack, elevating the dislocation density and the local stress. This stress elevation enhances crack propagation and significantly lowers the steady state fracture toughness with respect to conventional plasticity. Important insight is gained into fracture phenomena that cannot be explained...

  16. Thermo-plastic finite element analysis for metal honeycomb structure

    Directory of Open Access Journals (Sweden)

    Ji Zhanling

    2013-01-01

    Full Text Available This paper deals with thermal-plastic analysis for the metal honeycomb structure. The heat transfer equation and thermal elastoplastic constitutive equation of a multilayer panel are established and studied numerically using ANSYS software. The paper elucidates that only the outer skin produces easily plastic deformation, and the outer skin still exists some residual stress and residual deformation after cooling. The dynamic evolution of plastic deformation and material performance degradation under high energy thermal load are revealed.

  17. 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.

  18. Seabirds, gyres and global trends in plastic pollution

    NARCIS (Netherlands)

    Franeker, van J.A.; Law, K.L.

    2015-01-01

    Fulmars are effective biological indicators of the abundance of floating plastic marine debris. Long-term data reveal high plastic abundance in the southern North Sea, gradually decreasing to the north at increasing distance from population centres, with lowest levels in high-arctic waters. Since

  19. Arabidopsis thaliana population analysis reveals high plasticity of the genomic region spanning MSH2, AT3G18530 and AT3G18535 genes and provides evidence for NAHR-driven recurrent CNV events occurring in this location.

    Science.gov (United States)

    Zmienko, Agnieszka; Samelak-Czajka, Anna; Kozlowski, Piotr; Szymanska, Maja; Figlerowicz, Marek

    2016-11-08

    Intraspecies copy number variations (CNVs), defined as unbalanced structural variations of specific genomic loci, ≥1 kb in size, are present in the genomes of animals and plants. A growing number of examples indicate that CNVs may have functional significance and contribute to phenotypic diversity. In the model plant Arabidopsis thaliana at least several hundred protein-coding genes might display CNV; however, locus-specific genotyping studies in this plant have not been conducted. We analyzed the natural CNVs in the region overlapping MSH2 gene that encodes the DNA mismatch repair protein, and AT3G18530 and AT3G18535 genes that encode poorly characterized proteins. By applying multiplex ligation-dependent probe amplification and droplet digital PCR we genotyped those genes in 189 A. thaliana accessions. We found that AT3G18530 and AT3G18535 were duplicated (2-14 times) in 20 and deleted in 101 accessions. MSH2 was duplicated in 12 accessions (up to 12-14 copies) but never deleted. In all but one case, the MSH2 duplications were associated with those of AT3G18530 and AT3G18535. Considering the structure of the CNVs, we distinguished 5 genotypes for this region, determined their frequency and geographical distribution. We defined the CNV breakpoints in 35 accessions with AT3G18530 and AT3G18535 deletions and tandem duplications and showed that they were reciprocal events, resulting from non-allelic homologous recombination between 99 %-identical sequences flanking these genes. The widespread geographical distribution of the deletions supported by the SNP and linkage disequilibrium analyses of the genomic sequence confirmed the recurrent nature of this CNV. We characterized in detail for the first time the complex multiallelic CNV in Arabidopsis genome. The region encoding MSH2, AT3G18530 and AT3G18535 genes shows enormous variation of copy numbers among natural ecotypes, being a remarkable example of high Arabidopsis genome plasticity. We provided the molecular

  20. Small scale plasticity - an ad hoc review

    International Nuclear Information System (INIS)

    Ng, K S; Ngan, A H W

    2009-01-01

    Recent uniaxial compression experiments on FCC metallic micro-crystals revealed their unique deformation behaviour as compared to the bulk situation. The distinctive behaviour includes size-dependent proof strength, intermittent plasticity during loading and creep, low steady-state creep rate, heterogeneous slip, limited dislocation accumulation, etc. This paper reviews the key experimental observations as well as modelling efforts for the underlying mechanisms.

  1. 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.

  2. 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.)

  3. Plastics: Friend or foe?

    Directory of Open Access Journals (Sweden)

    O P Gupta

    2018-01-01

    Full Text Available Plastics has been playing a very significant role in our life. Being light weight, inexpensive and heving good insulating properties it is being used in all aspects of life, from clothes to contact lenses and from mobile phones to automobiles as well as in medical equipments, However it is not biodegradable, and while degrading to fragments it gets converted in to microplastics and nanoplastics The plastic waste is being recognized as an environmental hazard, since these micr- and nanoplastics find way from landfills to water and foods, It is said that we are not only using, but we are eating, drinking and even braething the plastics. These microplastics in body release certain hazardous chemicals and found to be disrupting functions of certain endocrine organs. Whether the rising prevalence of Diabetes, thyroid disorders or infirtility etc., are realated to the plastics?

  4. 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.

  5. A Plastic Menagerie

    Science.gov (United States)

    Hadley, Mary Jane

    2010-01-01

    Bobble heads had become quite popular, depicting all sorts of sports figures, animals, and even presidents. In this article, the author describes how her fourth graders made bobble head sculptures out of empty plastic drink bottles. (Contains 1 online resource.)

  6. 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.

  7. 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.

  8. Recycling of packing plastics

    International Nuclear Information System (INIS)

    Gintenreiter-Koegl, S.

    2001-05-01

    The ordinance on the avoidance of packaging waste was a serious intervention in the public and private waste management in Austria. Above all the high expenses for an overall packaging waste collection and the recycling of packaging plastics were criticized. The landfill ordinance comes into force in 2004 and this means another major change in the Austrian waste management system. In the course of this change the overall collection and the recycling and recovery of waste streams, especially of the high caloric plastics waste, have to be discussed again. The goal of this work was on the one hand to develop and adapt the hydrocracking process for the recovery of mixed plastics waste and to show a possible application in Austria. On the other hand the work shows the technical, ecological and economical conditions for packaging plastics recycling and recovery in order to find optimum applications for the processes and to examine their contribution to a sustainable development. A hydrocracking test plant for the processing of mixed plastic wastes was built and had been running for about three years. The tests were carried out successfully and the suitability of the technology for the recovery of packaging plastics could be shown. Results show at least a 35 % yield of fuel. The hydrocracking technology is quite common in the oil industries and therefore an integration on a refinery site is suggested. (author)

  9. 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

  10. [Minus]Plastic: Influencing Pro-Environmental Attitudes among Singaporean Youth

    Science.gov (United States)

    Chib, Arul; Chiew, Han Joo; Kumar, Chitraveni; Choon, Lim Geok; Ale, Komathi

    2009-01-01

    Plastics have much to offer as a modern convenience, but lack of responsible plastic waste management habits can lead to potentially harmful environmental effects. Past environmental initiatives revealed a lack of understanding about youth attitudes towards pro-environmental issues. [minus]plastic, an online public environmental promotional…

  11. The plasticity of clays

    Science.gov (United States)

    Group, F.F.

    1905-01-01

    (1) Sand injures plasticity little at first because the grains are suspended in a plastic mass. It is only when grains are abundant enough to come in contact with their neighbors, that the effect becomes serious, and then both strength and amount of possible flow are injured. (2) Certain rare organic colloids increase the plasticity by rendering the water viscous. (3) Fineness also tends to increase plasticity. (4) Plane surfaces (plates) increase the amount of possible flow. They also give a chance for lubrication by thinner films, thus increasing the friction of film, and the strength of the whole mass. The action of plates is thus twofold ; but fineness may be carried to such an extent as to break up plate-like grains into angular fragments. The beneficial effects of plates are also decreased by the fact that each is so closely surrounded by others in the mass. (5) Molecular attraction is twofold in increasing plasticity. As the attraction increases, the coherence and strength of the mass increase, and the amount of possible deformation before crumbling also increases. Fineness increases this action by requiring more water. Colloids and crystalloids in solution may also increase the attraction. It is thus seen to be more active than any other single factor.

  12. Plastics control paraffin buildup

    Energy Technology Data Exchange (ETDEWEB)

    1965-06-01

    Paraffin buildup in producing oil wells has been virtually eliminated by the use of plastic-coated sucker rods. The payout of the plasticing process is generally reached in less than a year, and the paraffin buildup may be inhibited for 10 yr or longer. Most of the plants applying plastic coatings to sucker rods are now fully automated, though a few still offer the hand-sprayed coating that some operators prefer. The several steps involved are described. The ideal plastic for the job is resistant to chemicals at high and low temperatures, flexible, has good adhesion, abrasion resistance, impact resistance, and a smooth glossy finish. The phenol aldehyde and epoxy resins presently offered by the industry fulfill these specifications very well; the multicoating and multibaking techniques improve their performance. Due to wide variations in the severity of the paraffin problem from one oil field to another, there is no general rule to estimate the possible savings from using plastic-coated sucker rods. The process, however, does appear to do a remarkable job in controlling paraffin buildup wherever it is a problem in producing oil by pump.

  13. Investigation into Plastic Cards

    Directory of Open Access Journals (Sweden)

    Neringa Stašelytė

    2015-03-01

    Full Text Available The article examines the strength of laminating plastic cards at different lamination temperatures. For investigation purposes, two types of plastic substrate and films have been used. Laminate strength has been tested (CMYK to establish the impact of colours on the strength of laminate. The paper compares inks supplied by two different producers. The colour characteristics of CIE L*a*b* space before and after the lamination process have been found. According to lamination strength and characteristics of the colours, the most suitable inks, temperature and films have been chosen.

  14. Joining by plastic deformation

    DEFF Research Database (Denmark)

    Mori, Ken-ichiro; Bay, Niels; Fratini, Livan

    2013-01-01

    As the scale and complexity of products such as aircraft and cars increase, demand for new functional processes to join mechanical parts grows. The use of plastic deformation for joining parts potentially offers improved accuracy, reliability and environmental safety as well as creating opportuni......As the scale and complexity of products such as aircraft and cars increase, demand for new functional processes to join mechanical parts grows. The use of plastic deformation for joining parts potentially offers improved accuracy, reliability and environmental safety as well as creating...

  15. 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)

  16. Plastic flashtube chambers

    International Nuclear Information System (INIS)

    Frisken, W.R.

    1977-01-01

    A brief discussion is given of the use and operation of plastic flashtube chambers. Gas leaks, electric pulsing, the glow discharge, and readout methods are considered. Three distinct problems with high rate applications deal with resolving time, dead time, and polarization/neutralization of the chamber

  17. Plastic Surgery: Tackling Misconceptions

    African Journals Online (AJOL)

    will succeed. First impressions tend to last, and if young people's first impression of plastic surgeons is that they spend much of their time doing cosmetic surgery then this is a first impression that might be long ... Res 2014;4 Suppl S3:169‑70. Access this article online. Quick Response Code: Website: www.amhsr.org. DOI:.

  18. Biobased Plastics 2012

    NARCIS (Netherlands)

    Bolck, C.H.; Ravenstijn, J.; Molenveld, K.; Harmsen, P.F.H.

    2011-01-01

    Dit boek geeft inzicht in de huidige op de markt verkrijgbare biobased plastics en de te verwachten ontwikkelingen. Er wordt gekeken naar zowel thermoplastische als thermohardende materialen. Het boek biedt inzicht in de productie, verwerking en eigenschappen van de verschillende types. Daarnaast

  19. New plastic recycling technology

    Science.gov (United States)

    Greater than 60% of the total plastic content of municipal solid waste is comprised of polyolefins (high-density, low-density, and linear polyethylene and polypropylene. Polyethylene (PE) is the largest-volume component but presents a challenge due to the absence of low-energy de...

  20. Reliability of Plastic Slabs

    DEFF Research Database (Denmark)

    Thoft-Christensen, Palle

    1989-01-01

    In the paper it is shown how upper and lower bounds for the reliability of plastic slabs can be determined. For the fundamental case it is shown that optimal bounds of a deterministic and a stochastic analysis are obtained on the basis of the same failure mechanisms and the same stress fields....

  1. 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

  2. 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.

  3. 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....

  4. Maladaptive synaptic plasticity in L-DOPA-induced dyskinesia

    Directory of Open Access Journals (Sweden)

    Qiang Wang

    2016-12-01

    Full Text Available The emergence of L-DOPA-induced dyskinesia (LID in patients with Parkinson disease (PD could be due to maladaptive plasticity of corticostriatal synapses in response to L-DOPA treatment. A series of recent studies has revealed that LID is associated with marked morphological plasticity of striatal dendritic spines, particularly cell type-specific structural plasticity of medium spiny neurons (MSNs in the striatum. In addition, evidence demonstrating the occurrence of plastic adaptations, including aberrant morphological and functional features, in multiple components of cortico-basal ganglionic circuitry, such as primary motor cortex (M1 and basal ganglia (BG output nuclei. These adaptations have been implicated in the pathophysiology of LID. Here, we briefly review recent studies that have addressed maladaptive plastic changes within the cortico-BG loop in dyskinetic animal models of PD and patients with PD.

  5. 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.

  6. Introduction to Computational Plasticity

    International Nuclear Information System (INIS)

    Hartley, P

    2006-01-01

    The focus of the book on computational plasticity embodies techniques of relevance not only to academic researchers, but also of interest to industrialists engaged in the production of components using bulk or sheet forming processes. Of particular interest is the guidance on how to create modules for use with the commercial system Abaqus for specific types of material behaviour. The book is in two parts, the first of which contains six chapters, starting with microplasticity, but predominantly on continuum plasticity. The first chapter on microplasticty gives a brief description of the grain structure of metals and the existence of slip systems within the grains. This provides an introduction to the concept of incompressibility during plastic deformation, the nature of plastic yield and the importance of the critically resolved shear stress on the slip planes (Schmid's law). Some knowledge of the notation commonly used to describe slip systems is assumed, which will be familiar to students of metallurgy, but anyone with a more general engineering background may need to undertake additional reading to understand the various descriptions. Chapter two introduces one of several yield criteria, that normally attributed to von Mises (though historians of mechanics might argue over who was first to develop the theory of yielding associated with strain energy density), and its two or three-dimensional representation as a yield surface. The expansion of the yield surface during plastic deformation, its translation due to kinematic hardening and the Bauschinger effect in reversed loading are described with a direct link to the material stress-strain curve. The assumption, that the increment of strain is normal to the yield surface, the normality principle, is introduced. Uniaxial loading of an elastic-plastic material is used as an example in which to develop expressions to describe increments in stress and strain. The full presentation of numerous expressions, tensors and

  7. Plasticity modeling & computation

    CERN Document Server

    Borja, Ronaldo I

    2013-01-01

    There have been many excellent books written on the subject of plastic deformation in solids, but rarely can one find a textbook on this subject. “Plasticity Modeling & Computation” is a textbook written specifically for students who want to learn the theoretical, mathematical, and computational aspects of inelastic deformation in solids. It adopts a simple narrative style that is not mathematically overbearing, and has been written to emulate a professor giving a lecture on this subject inside a classroom. Each section is written to provide a balance between the relevant equations and the explanations behind them. Where relevant, sections end with one or more exercises designed to reinforce the understanding of the “lecture.” Color figures enhance the presentation and make the book very pleasant to read. For professors planning to use this textbook for their classes, the contents are sufficient for Parts A and B that can be taught in sequence over a period of two semesters or quarters.

  8. 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

  9. 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

  10. 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

  11. Mesocycles in conserving plastics

    DEFF Research Database (Denmark)

    Shashoua, Yvonne

    2016-01-01

    driven by the need to balance the requirements for reversibility in conservation practices with the artist’s intent and significance. Developments within each of the three mesocycles from the 1990s to date are discussed in this article. Environmental science and toxicology of waste plastics offer a novel...... source of information about real time degradation in terrestrial and marine microenvironments that seems likely to contribute to the conservation of similar materials in contemporary artworks....

  12. Seabirds, gyres and global trends in plastic pollution.

    Science.gov (United States)

    van Franeker, Jan A; Law, Kara Lavender

    2015-08-01

    Fulmars are effective biological indicators of the abundance of floating plastic marine debris. Long-term data reveal high plastic abundance in the southern North Sea, gradually decreasing to the north at increasing distance from population centres, with lowest levels in high-arctic waters. Since the 1980s, pre-production plastic pellets in North Sea fulmars have decreased by ∼75%, while user plastics varied without a strong overall change. Similar trends were found in net-collected floating plastic debris in the North Atlantic subtropical gyre, with a ∼75% decrease in plastic pellets and no obvious trend in user plastic. The decreases in pellets suggest that changes in litter input are rapidly visible in the environment not only close to presumed sources, but also far from land. Floating plastic debris is rapidly "lost" from the ocean surface to other as-yet undetermined sinks in the marine environment. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

  13. Plastic footwear for leprosy.

    Science.gov (United States)

    Antia, N H

    1990-03-01

    The anaesthetic foot in leprosy poses the most major problem in the rehabilitation of its patients. Various attempts have been made to produce protective footwear such as the microcellular rubber-car-tyre sandals. Unfortunately these attempts have had little success on a large scale because of the inability to produce them in large numbers and the stigma attached to such unusual footwear. While such footwear may be superior to the 'tennis' shoe in protecting the foot from injury by the penetration of sharp objects, it fails to distribute the weight-bearing forces which is the major cause of plantar damage and ulceration in the anaesthetic foot. This can be achieved by providing rigidity to the sole, as demonstrated by the healing of ulcers in plaster of paris casts or the rigid wooden clog. A new type of moulded plastic footwear has been evolved in conjunction with the plastic footwear industry which provides footwear that can be mass produced at a low price and which overcomes the stigma of leprosy. Controlled rigidity is provided by the incorporation of a spring steel shank between the sponge insole and the hard wearing plastic sole. Trials have demonstrated both the acceptability of the footwear and its protective effects as well as its hard wearing properties.

  14. Plastic waste disposal apparatus

    Energy Technology Data Exchange (ETDEWEB)

    Kito, S

    1972-05-01

    A test plant plastic incinerator was constructed by the Takuma Boiler Manufacturing Co. for Sekisui Chemical Industries, and the use of a continuous feed spreader was found to be most effective for prevention of black smoke, and the use of a venturi scrubber proved to be effective for elimination of hydrogen chloride gas. The incinerator was designed for combustion of polyvinyl chloride exclusively, but it is also applicable for combustion of other plastics. When burning polyethylene, polypropylene, or polystyrene, (those plastics which do not produce toxic gases), the incinerator requires no scrubber for the combustion gas. The system may or may not have a pretreatment apparatus. For an incinerator with a pretreatment system, the flow chart comprises a pit, a supply crane, a vibration feeder, a metal eliminator, a rotation shredder, a continuous screw feeder with a quantitative supply hopper, a pretreatment chamber (300 C dry distillation), a quantitative supply hopper, and the incinerator. The incinerator is a flat non-grid type combustion chamber with an oil burner and many air nozzles. From the incinerator, ashes are sent by an ash conveyor to an ash bunker. The combustion gas goes to the boiler, and the water supplied the boiler water pump creates steam. The heat from the gas is sent back to the pretreatment system through a heat exchanger. The gas then goes to a venturi scrubber and goes out from a stack.

  15. 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.

  16. 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

  17. [The role of plastic shock absorbers in dental implantation].

    Science.gov (United States)

    Szücs, A; Divinyi, T; Belina, K; Vörös, G

    1999-01-01

    The mechanical behaviour of different plastics (PE, PP, PI, PA, ABS, POM) was examined by static and dynamic loading. Detection of microdeformations and photoelastic stress analysis served as the examination method. According to the results, polyethylene is unsuitable, however the other plastics, with clauses, are suitable as shock absorbers. Apart from the mechanical investigation photoelastic stress analysis also revealed the benefit of osseointegration in force transmission to the bone.

  18. Ocean acidification challenges copepod phenotypic plasticity

    Directory of Open Access Journals (Sweden)

    A. Vehmaa

    2016-11-01

    Full Text Available Ocean acidification is challenging phenotypic plasticity of individuals and populations. Calanoid copepods (zooplankton are shown to be fairly plastic against altered pH conditions, and laboratory studies indicate that transgenerational effects are one mechanism behind this plasticity. We studied phenotypic plasticity of the copepod Acartia sp. in the course of a pelagic, large-volume mesocosm study that was conducted to investigate ecosystem and biogeochemical responses to ocean acidification. We measured copepod egg production rate, egg-hatching success, adult female size and adult female antioxidant capacity (ORAC as a function of acidification (fCO2  ∼  365–1231 µatm and as a function of quantity and quality of their diet. We used an egg transplant experiment to reveal whether transgenerational effects can alleviate the possible negative effects of ocean acidification on offspring development. We found significant negative effects of ocean acidification on adult female size. In addition, we found signs of a possible threshold at high fCO2, above which adaptive maternal effects cannot alleviate the negative effects of acidification on egg-hatching and nauplii development. We did not find support for the hypothesis that insufficient food quantity (total particulate carbon < 55 µm or quality (C : N weakens the transgenerational effects. However, females with high-ORAC-produced eggs with high hatching success. Overall, these results indicate that Acartia sp. could be affected by projected near-future CO2 levels.

  19. Ocean acidification challenges copepod reproductive plasticity

    Science.gov (United States)

    Vehmaa, A.; Almén, A.-K.; Brutemark, A.; Paul, A.; Riebesell, U.; Furuhagen, S.; Engström-Öst, J.

    2015-11-01

    Ocean acidification is challenging phenotypic plasticity of individuals and populations. Calanoid copepods (zooplankton) are shown to be fairly plastic against altered pH conditions, and laboratory studies indicate that transgenerational effects are one mechanism behind this plasticity. We studied phenotypic plasticity of the copepod Acartia bifilosa in the course of a pelagic, large-volume mesocosm study that was conducted to investigate ecosystem and biogeochemical responses to ocean acidification. We measured copepod egg production rate, egg hatching success, adult female size and adult female antioxidant capacity (ORAC) as a function of acidification (fCO2 ~ 365-1231 μatm), and as a function of quantity and quality of their diet. We used an egg transplant experiment to reveal if transgenerational effects can alleviate the possible negative effects of ocean acidification on offspring development. We found significant negative effects of ocean acidification on adult female copepod size and egg hatching success. In addition, we found a threshold of fCO2 concentration (~ 1000 μatm), above which adaptive maternal effects cannot alleviate the negative effects of acidification on egg hatching and nauplii development. We did not find support for the hypothesis that insufficient food quantity (total particulate carbon ~ 55 μm) or quality (C : N) weakens the transgenerational effects. However, females with high ORAC produced eggs with high hatching success. Overall, these results indicate that A. bifilosa could be affected by projected near future CO2 levels.

  20. Ocean acidification challenges copepod phenotypic plasticity

    Science.gov (United States)

    Vehmaa, Anu; Almén, Anna-Karin; Brutemark, Andreas; Paul, Allanah; Riebesell, Ulf; Furuhagen, Sara; Engström-Öst, Jonna

    2016-11-01

    Ocean acidification is challenging phenotypic plasticity of individuals and populations. Calanoid copepods (zooplankton) are shown to be fairly plastic against altered pH conditions, and laboratory studies indicate that transgenerational effects are one mechanism behind this plasticity. We studied phenotypic plasticity of the copepod Acartia sp. in the course of a pelagic, large-volume mesocosm study that was conducted to investigate ecosystem and biogeochemical responses to ocean acidification. We measured copepod egg production rate, egg-hatching success, adult female size and adult female antioxidant capacity (ORAC) as a function of acidification (fCO2 ˜ 365-1231 µatm) and as a function of quantity and quality of their diet. We used an egg transplant experiment to reveal whether transgenerational effects can alleviate the possible negative effects of ocean acidification on offspring development. We found significant negative effects of ocean acidification on adult female size. In addition, we found signs of a possible threshold at high fCO2, above which adaptive maternal effects cannot alleviate the negative effects of acidification on egg-hatching and nauplii development. We did not find support for the hypothesis that insufficient food quantity (total particulate carbon < 55 µm) or quality (C : N) weakens the transgenerational effects. However, females with high-ORAC-produced eggs with high hatching success. Overall, these results indicate that Acartia sp. could be affected by projected near-future CO2 levels.

  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. 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.

  4. 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.

  5. A Rare Case of Idiopathic Plastic Bronchitis

    Directory of Open Access Journals (Sweden)

    Mohammed Raoufi

    2017-01-01

    Full Text Available Plastic bronchitis is a rare disorder characterized by formation of large, branching bronchial casts, which are often expectorated. We present an interesting case of a 35-year-old woman who presented for evaluation of a chronic cough productive of voluminous secretions. Clinical and radiological examination confirmed a total left lung atelectasis without any pathological mediastinal node. Flexible bronchoscopy demonstrated tenacious, thick, and sticky whitish secretions blocking the left stem bronchus. This material was extracted, and inspection demonstrated a bronchial cast, whose pathological analysis revealed necrotic epithelial cells, some eosinophils, and Charcot-Leyden crystals. Two days after bronchoscopy, the patient rejected more bronchial casts, and dyspnea improved. Control of chest x-ray revealed complete left lung aeration and the diagnosis of idiopathic plastic bronchitis was obtained. This article shows the interest in clinical practice to evoke the diagnosis of plastic bronchitis in front of a productive chronic cough. Our case illustrates a rare clinical presentation represented by an atelectasis of an entire lung.

  6. Plastics pipe couplings

    International Nuclear Information System (INIS)

    Glover, J.B.

    1980-07-01

    A method is described of making a pipe coupling of the type comprising a plastics socket and a resilient annular sealing member secured in the mouth thereof, in which the material of at least one component of the coupling is subjected to irradiation with high energy radiation whereby the material is caused to undergo cross-linking. As examples, the coupling may comprise a polyethylene or plasticised PVC socket the material of which is subjected to irradiation, and the sealing member may be moulded from a thermoplastic elastomer which is subjected to irradiation. (U.K.)

  7. 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.

  8. Strand Plasticity Governs Fatigue in Colloidal Gels

    Science.gov (United States)

    van Doorn, Jan Maarten; Verweij, Joanne E.; Sprakel, Joris; van der Gucht, Jasper

    2018-05-01

    The repeated loading of a solid leads to microstructural damage that ultimately results in catastrophic material failure. While posing a major threat to the stability of virtually all materials, the microscopic origins of fatigue, especially for soft solids, remain elusive. Here we explore fatigue in colloidal gels as prototypical inhomogeneous soft solids by combining experiments and computer simulations. Our results reveal how mechanical loading leads to irreversible strand stretching, which builds slack into the network that softens the solid at small strains and causes strain hardening at larger deformations. We thus find that microscopic plasticity governs fatigue at much larger scales. This gives rise to a new picture of fatigue in soft thermal solids and calls for new theoretical descriptions of soft gel mechanics in which local plasticity is taken into account.

  9. 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

  10. Plastic ingestion by sea turtles in Paraíba State, Northeast Brazil

    Directory of Open Access Journals (Sweden)

    Camila Poli

    2015-09-01

    Full Text Available ABSTRACT Currently, plastics are recognized as a major pollutant of the marine environment, representing a serious threat to ocean wildlife. Here, we examined the occurrence and effects of plastic ingestion by sea turtles found stranded along the coast of Paraíba State, Brazil from August 2009 to July 2010. Ninety-eight digestive tracts were examined, with plastic found in 20 (20.4%. Sixty five percent (n = 13 of turtles with plastic in the digestive tract were green turtles (Chelonia mydas, 25% (n = 5 were hawksbills (Eretmochelys imbricata, and 10% (n = 2 were olive ridley (Lepidochelys olivacea. More plastic was found in the intestine (85% than in other parts of the gastrointestinal tract. We observed complete blockage of the gastrointestinal tract due to the presence of plastic in 13 of the 20 turtles that had ingested plastic. No correlation was found between the curved carapace length (CCL and the number or mass of the plastic ingested items. Significant differences were found between the intake of hard and soft plastic and the ingestion of white/transparent and colored plastic, with soft and white/transparent plastics being more commonly ingested. This study reveals the serious problem of plastic pollution to sea turtles at the area.

  11. New polyvinylchloride plasticizers

    Directory of Open Access Journals (Sweden)

    MAZITOVA Aliya Karamovna

    2017-11-01

    Full Text Available One of the main large-capacity polymers of modern chemical industry is polyvinylchloride (PVC. Polyvinylchloride is characterized by many useful engineering properties – chemical firmness in different environments, good electric properties, etc. It explains immensely various use of materials on the basis of PVC in different engineering industries. It is cable, building, light industries, mechanical engineering and automotive industry where PVC is widely applied. One of the reasons why PVC production is dramatically growing is that there is no yet other polymer which could be subjected to such various modifying as it is done with PVC. However under normal temperature this polymer is fragile and isn't elastic that limits the field of its application. Rapid growth of production of polyvinylchloride is explained by its ability to modify properties, due to introduction of special additives when processing. Introduction of plasticizers – mostlly esters of organic and inorganic acids – into PVC allows significant changing properties of polymer. Plasticizers facilitate process of receiving polymeric composition, increase flexibility and elasticity of the final polymeric product due to internal modification of polymeric molecule.

  12. Americium behaviour in plastic vessels

    International Nuclear Information System (INIS)

    Legarda, F.; Herranz, M.; Idoeta, R.; Abelairas, A.

    2010-01-01

    The adsorption of 241 Am dissolved in water in different plastic storage vessels was determined. Three different plastics were investigated with natural and distilled waters and the retention of 241 Am by these plastics was studied. The same was done by varying vessel agitation time, vessel agitation speed, surface/volume ratio of water in the vessels and water pH. Adsorptions were measured to be between 0% and 70%. The adsorption of 241 Am is minimized with no water agitation, with PET or PVC plastics, and by water acidification.

  13. Americium behaviour in plastic vessels

    Energy Technology Data Exchange (ETDEWEB)

    Legarda, F.; Herranz, M. [Departamento de Ingenieria Nuclear y Mecanica de Fluidos, Escuela Tecnica Superior de Ingenieria de Bilbao, Universidad del Pais Vasco (UPV/EHU), Alameda de Urquijo s/n, 48013 Bilbao (Spain); Idoeta, R., E-mail: raquel.idoeta@ehu.e [Departamento de Ingenieria Nuclear y Mecanica de Fluidos, Escuela Tecnica Superior de Ingenieria de Bilbao, Universidad del Pais Vasco (UPV/EHU), Alameda de Urquijo s/n, 48013 Bilbao (Spain); Abelairas, A. [Departamento de Ingenieria Nuclear y Mecanica de Fluidos, Escuela Tecnica Superior de Ingenieria de Bilbao, Universidad del Pais Vasco (UPV/EHU), Alameda de Urquijo s/n, 48013 Bilbao (Spain)

    2010-07-15

    The adsorption of {sup 241}Am dissolved in water in different plastic storage vessels was determined. Three different plastics were investigated with natural and distilled waters and the retention of {sup 241}Am by these plastics was studied. The same was done by varying vessel agitation time, vessel agitation speed, surface/volume ratio of water in the vessels and water pH. Adsorptions were measured to be between 0% and 70%. The adsorption of {sup 241}Am is minimized with no water agitation, with PET or PVC plastics, and by water acidification.

  14. Americium behaviour in plastic vessels.

    Science.gov (United States)

    Legarda, F; Herranz, M; Idoeta, R; Abelairas, A

    2010-01-01

    The adsorption of (241)Am dissolved in water in different plastic storage vessels was determined. Three different plastics were investigated with natural and distilled waters and the retention of (241)Am by these plastics was studied. The same was done by varying vessel agitation time, vessel agitation speed, surface/volume ratio of water in the vessels and water pH. Adsorptions were measured to be between 0% and 70%. The adsorption of (241)Am is minimized with no water agitation, with PET or PVC plastics, and by water acidification. Copyright 2009 Elsevier Ltd. All rights reserved.

  15. Experimental analysis of plastic materials containing radionuclides for decontamination viability

    International Nuclear Information System (INIS)

    Tazaki, Kazue; Nakano, Mikio; Takehara, Teruaki; Ishigaki, Yasuhito; Nakagawa, Hideaki

    2015-01-01

    After the Fukushima Daiichi Nuclear Power Plant (FDNPP) accident on 11 March, 2011, the high radioactive dosage was found in polluted water for agriculture use at Baba, Haramachi, Minami-Soma, Fukushima Prefecture, Japan. Field experiment for decontamination of water had been studied by using commercial plastic materials. The agricultural water comes from Tetsuzan dam is full of radioactive-contaminated water. Experimental analysis showed that the plastic materials can take up radioactive elements for several months soaked in the polluted agricultural water. The quantitative analyses using X-ray fluorescence analysis, Ge semiconductor and scanning electron microscopy equipped with energy dispersive X-ray spectrometer (SEM-EDS), revealed the detection of the radionuclides on the plastic materials with diatom and clays. The results suggest the adsorption of radionuclides on the surface of plastic materials due to FDNPP accident. The plastic materials associated with clays and diatoms could be stronger carriers of radionuclides in the polluted water. Adherence of diatoms to the plastic fiber in the water for 7 months suggested that some plastic materials were taking up heavy metals (Zn, Ba, Pb, Sb) with radioactive elements (Cs etc.). Mechanisms by which radioactive pollutants and microorganisms are adsorbed onto and desorbed from clays at aqueous interface can be understood by combining chemical analysis with electron microscopy observation. (author)

  16. 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

  17. 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

  18. Evaluation of biodegradable plastics for rubber seedling applications

    Science.gov (United States)

    Mansor, Mohd Khairulniza; Dayang Habibah A. I., H.; Kamal, Mazlina Mustafa

    2015-08-01

    The main negative consequence of conventional plastics in agriculture is related to handling the wastes plasticand the associated environmental impact. Hence, a study of different types of potentially biodegradable plastics used for nursery applications have been evaluated on its mechanical,water absorption propertiesand Fourier transform infra-red (FTIR) spectroscopy. Supplied samples from different companies were designated as SF, CF and CO. Most of the polybags exhibited mechanical properties quite similar to the conventional plastics (polybag LDPE). CO polybag which is based on PVA however had extensively higher tensile strength and water absorption properties. FTIR study revealed a characteristics absorbance of conventional plastic, SF, CF and CO biodegradable polybag are associated with polyethylene, poly(butylene adipate-co-terephthalate) (PBAT), polyethylene and polyvinyl alcohol (PVA) structures respectively.

  19. Sustainable reverse logistics for household plastic waste

    NARCIS (Netherlands)

    Bing, X.

    2014-01-01

    Summary of the thesis titled “Sustainable Reverse Logistics for Household Plastic Waste”

    PhD Candidate: Xiaoyun Bing

    Recycled plastic can be used in the manufacturing of plastic products to reduce the use of virgin plastics material. The cost of recycled plastics is usually lower

  20. Marine microbe with potential to adhere and degrade plastic structures

    Directory of Open Access Journals (Sweden)

    Alka Kumari

    2017-10-01

    Full Text Available Extensive usages of plastics have led to their accumulation as a contaminant in natural environment worldwide. Plastic is an inert and non-biodegradable material, due to its complex structure and hydrophobic backbone [1]. Conventional methods for reduction of plastic waste such as burning, land-filling release unwanted toxic chemicals to the environment and harming living organism of land as well as the ocean. There is growing interest in development of strategies for the degradation of plastic wastes to clean the environment [2]. Marine bacteria have evolved with the capability to adapt and grow in the diverse environmental conditions [3]. We studied the ability of marine bacteria for destabilization and utilization of different plastic films (LDPE, HDPE, PVC and PET as a sole source of carbon. An active bacterial strain AIIW2 was selected based on the triphenyl tetrazolium chloride reduction assay, and it was identified as Bacillus species based on 16S rRNA gene sequence. The viability of the strain over the plastic surface was studied and confirmed by bacLight assay with fluorescent probes. Scanning Electron Microscope and Atomic Force Microscope images suggested that bacterial interaction over the plastic surface is causing deterioration and roughness with increasing bacterial incubation time. In Fourier transform infrared spectra of treated plastic film evidenced stretching of the (-CH alkane rock chain and (-CO carbonyl region, suggested the oxidative activities of the bacteria. The results revealed that ability of bacterial strain for instigating their colonization over plastic films and deteriorating the polymeric structure in the absence of other carbon sources [4]. Moreover, production of extracellular enzymes such as esterase, laccase, and dehalogenase which are reported to support utilization of plastics was confirmed by plate assays. In concise, our results suggested that the marine bacterial strain AIIW2 have the ability to utilize

  1. Mathematics revealed

    CERN Document Server

    Berman, Elizabeth

    1979-01-01

    Mathematics Revealed focuses on the principles, processes, operations, and exercises in mathematics.The book first offers information on whole numbers, fractions, and decimals and percents. Discussions focus on measuring length, percent, decimals, numbers as products, addition and subtraction of fractions, mixed numbers and ratios, division of fractions, addition, subtraction, multiplication, and division. The text then examines positive and negative numbers and powers and computation. Topics include division and averages, multiplication, ratios, and measurements, scientific notation and estim

  2. 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.

  3. Nigerian Journal of Plastic Surgery

    African Journals Online (AJOL)

    The Nigerian Journal of Plastic Surgery has its objectives in publishing original articles about developments in all areas related to plastic and reconstructive surgery as well as to trauma surgery. It also serves as a means of providing a forum for correspondence, information and discussion. It also accepts review articles that ...

  4. Architecture of European Plastic Surgery

    NARCIS (Netherlands)

    Nicolai, J. -P. A.; Banic, A.; Molea, G.; Mazzola, R.; Poell, J. G.

    2006-01-01

    The architecture of European Plastic Surgery was published in 1996 [Nicolai JPA, Scuderi N. Plastic surgical Europe in an organogram. Eur J Plast Surg 1996; 19: 253-6.] It is the objective of this paper to update information of that article. Continuing medical education (CME), science, training,

  5. Imaging brain plasticity after trauma

    Institute of Scientific and Technical Information of China (English)

    Zhifeng Kou; Armin Iraji

    2014-01-01

    The brain is highly plastic after stroke or epilepsy;however, there is a paucity of brain plasticity investigation after traumatic brain injury (TBI). This mini review summarizes the most recent evidence of brain plasticity in human TBI patients from the perspective of advanced magnetic resonance imaging. Similar to other forms of acquired brain injury, TBI patients also demonstrat-ed both structural reorganization as well as functional compensation by the recruitment of other brain regions. However, the large scale brain network alterations after TBI are still unknown, and the ifeld is still short of proper means on how to guide the choice of TBI rehabilitation or treat-ment plan to promote brain plasticity. The authors also point out the new direction of brain plas-ticity investigation.

  6. Size effects in crystal plasticity

    DEFF Research Database (Denmark)

    Borg, Ulrik

    2007-01-01

    Numerical analyses of plasticity size effects have been carried out for different problems using a developed strain gradient crystal plasticiy theory. The theory employs higher order stresses as work conjugates to slip gradients and uses higher order boundary conditions. Problems on localization...... of plastic flow in a single crystal, grain boundary effects in a bicrystal, and grain size effects in a polycrystal are studied. Single crystals containing micro-scale voids have also been analyzed at different loading conditions with focus on the stress and deformation fields around the voids, on void...... growth and interaction between neighboring voids, and on a comparison between the developed strain gradient crystal plasticity theory and a discrete dislocation plasticity theory. Furthermore, voids and rigid inclusions in isotropic materials have been studied using a strain gradient plasticity theory...

  7. Computational strain gradient crystal plasticity

    DEFF Research Database (Denmark)

    Niordson, Christian Frithiof; Kysar, Jeffrey W.

    2014-01-01

    A numerical method for viscous strain gradient crystal plasticity theory is presented, which incorporates both energetic and dissipative gradient effects. The underlying minimum principles are discussed as well as convergence properties of the proposed finite element procedure. Three problems...... of plane crystal plasticity are studied: pure shear of a single crystal between rigid platens as well as plastic deformation around cylindrical voids in hexagonal close packed and face centered cubic crystals. Effective in-plane constitutive slip parameters for plane strain deformation of specifically...... oriented face centered cubic crystals are developed in terms of the crystallographic slip parameters. The effect on geometrically necessary dislocation structures introduced by plastic deformation is investigated as a function of the ratio of void radius to plasticity length scale....

  8. Influences on decision-making for undergoing plastic surgery: a mental models and quantitative assessment.

    Science.gov (United States)

    Darisi, Tanya; Thorne, Sarah; Iacobelli, Carolyn

    2005-09-01

    Research was conducted to gain insight into potential clients' decisions to undergo plastic surgery, their perception of benefits and risks, their judgment of outcomes, and their selection of a plastic surgeon. Semistructured, open-ended interviews were conducted with 60 people who expressed interest in plastic surgery. Qualitative analysis revealed their "mental models" regarding influences on their decision to undergo plastic surgery and their choice of a surgeon. Interview results were used to design a Web-based survey in which 644 individuals considering plastic surgery responded. The desire for change was the most direct motivator to undergo plastic surgery. Improvements to physical well-being were related to emotional and social benefits. When prompted about risks, participants mentioned physical, emotional, and social risks. Surgeon selection was a critical influence on decisions to undergo plastic surgery. Participants gave considerable weight to personal consultation and believed that finding the "right" plastic surgeon would minimize potential risks. Findings from the Web-based survey were similar to the mental models interviews in terms of benefit ratings but differed in risk ratings and surgeon selection criteria. The mental models interviews revealed that interview participants were thoughtful about their decision to undergo plastic surgery and focused on finding the right plastic surgeon.

  9. Plastic evolution behavior of H340LAD-Z steel by an optical method

    Energy Technology Data Exchange (ETDEWEB)

    Guo, Nan; Liang, Jin; Yu, Qiang; Qian, Boxing

    2017-02-01

    An optical method based on digital image correlation (DIC) technology was proposed to measure the plastic evolution of the high-strength low alloy steel H340LAD-Z. The basic principle of DIC technology is introduced, and then, the use of a 3D deformation measurement system and electronic universal testing machine to dynamically measure plastic evolution during the tensile yield stage is described. Through the full-field full-process measurement of plastic deformation during the yield stage in the 0°, 45° and 90° loading directions, the plastic evolution law was revealed. The results demonstrate that the proposed 3D DIC method can accurately reveal the starting and ending times for plastic evolution. The specimens in the three directions exhibit different plastic evolution behaviors, although they have similar yield strengths and yield times. The specimens in the 45° and 90° loading directions began to enter plastic deformation from bottom to top and the plastic area was maintained in a constant deformed state, while the evolution behavior in the 0° direction transited from both sides to the middle and plastic deformation was uneven. It is important to study plastic evolution of a metal sheet to determine the material properties and to provide an accurate basis for finite element modeling.

  10. Plastic evolution behavior of H340LAD-Z steel by an optical method

    International Nuclear Information System (INIS)

    Guo, Nan; Liang, Jin; Yu, Qiang; Qian, Boxing

    2017-01-01

    An optical method based on digital image correlation (DIC) technology was proposed to measure the plastic evolution of the high-strength low alloy steel H340LAD-Z. The basic principle of DIC technology is introduced, and then, the use of a 3D deformation measurement system and electronic universal testing machine to dynamically measure plastic evolution during the tensile yield stage is described. Through the full-field full-process measurement of plastic deformation during the yield stage in the 0°, 45° and 90° loading directions, the plastic evolution law was revealed. The results demonstrate that the proposed 3D DIC method can accurately reveal the starting and ending times for plastic evolution. The specimens in the three directions exhibit different plastic evolution behaviors, although they have similar yield strengths and yield times. The specimens in the 45° and 90° loading directions began to enter plastic deformation from bottom to top and the plastic area was maintained in a constant deformed state, while the evolution behavior in the 0° direction transited from both sides to the middle and plastic deformation was uneven. It is important to study plastic evolution of a metal sheet to determine the material properties and to provide an accurate basis for finite element modeling.

  11. Effects of Toxic Leachate from Commercial Plastics on Larval Survival and Settlement of the Barnacle Amphibalanus amphitrite.

    Science.gov (United States)

    Li, Heng-Xiang; Getzinger, Gordon J; Ferguson, P Lee; Orihuela, Beatriz; Zhu, Mei; Rittschof, Daniel

    2016-01-19

    Plastic pollution represents a major and growing global problem. It is well-known that plastics are a source of chemical contaminants to the aquatic environment and provide novel habitats for marine organisms. The present study quantified the impacts of plastic leachates from the seven categories of recyclable plastics on larval survival and settlement of barnacle Amphibalanus (=Balanus) amphitrite. Leachates from plastics significantly increased barnacle nauplii mortality at the highest tested concentrations (0.10 and 0.50 m(2)/L). Hydrophobicity (measured as surface energy) was positively correlated with mortality indicating that plastic surface chemistry may be an important factor in the effects of plastics on sessile organisms. Plastic leachates significantly inhibited barnacle cyprids settlement on glass at all tested concentrations. Settlement on plastic surfaces was significantly inhibited after 24 and 48 h, but settlement was not significantly inhibited compared to the controls for some plastics after 72-96 h. In 24 h exposure to seawater, we found larval toxicity and inhibition of settlement with all seven categories of recyclable commercial plastics. Chemical analysis revealed a complex mixture of substances released in plastic leachates. Leaching of toxic compounds from all plastics should be considered when assessing the risks of plastic pollution.

  12. 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.

  13. Community barcoding reveals little effect of ocean acidification on the composition of coastal plankton communities: Evidence from a long-term mesocosm study in the Gullmar Fjord, Skagerrak.

    Directory of Open Access Journals (Sweden)

    Julia A F Langer

    Full Text Available The acidification of the oceans could potentially alter marine plankton communities with consequences for ecosystem functioning. While several studies have investigated effects of ocean acidification on communities using traditional methods, few have used genetic analyses. Here, we use community barcoding to assess the impact of ocean acidification on the composition of a coastal plankton community in a large scale, in situ, long-term mesocosm experiment. High-throughput sequencing resulted in the identification of a wide range of planktonic taxa (Alveolata, Cryptophyta, Haptophyceae, Fungi, Metazoa, Hydrozoa, Rhizaria, Straminipila, Chlorophyta. Analyses based on predicted operational taxonomical units as well as taxonomical compositions revealed no differences between communities in high CO2 mesocosms (~ 760 μatm and those exposed to present-day CO2 conditions. Observed shifts in the planktonic community composition were mainly related to seasonal changes in temperature and nutrients. Furthermore, based on our investigations, the elevated CO2 did not affect the intraspecific diversity of the most common mesozooplankter, the calanoid copepod Pseudocalanus acuspes. Nevertheless, accompanying studies found temporary effects attributed to a raise in CO2. Differences in taxa composition between the CO2 treatments could, however, only be observed in a specific period of the experiment. Based on our genetic investigations, no compositional long-term shifts of the plankton communities exposed to elevated CO2 conditions were observed. Thus, we conclude that the compositions of planktonic communities, especially those in coastal areas, remain rather unaffected by increased CO2.

  14. Community barcoding reveals little effect of ocean acidification on the composition of coastal plankton communities: Evidence from a long-term mesocosm study in the Gullmar Fjord, Skagerrak.

    Science.gov (United States)

    Langer, Julia A F; Sharma, Rahul; Schmidt, Susanne I; Bahrdt, Sebastian; Horn, Henriette G; Algueró-Muñiz, María; Nam, Bora; Achterberg, Eric P; Riebesell, Ulf; Boersma, Maarten; Thines, Marco; Schwenk, Klaus

    2017-01-01

    The acidification of the oceans could potentially alter marine plankton communities with consequences for ecosystem functioning. While several studies have investigated effects of ocean acidification on communities using traditional methods, few have used genetic analyses. Here, we use community barcoding to assess the impact of ocean acidification on the composition of a coastal plankton community in a large scale, in situ, long-term mesocosm experiment. High-throughput sequencing resulted in the identification of a wide range of planktonic taxa (Alveolata, Cryptophyta, Haptophyceae, Fungi, Metazoa, Hydrozoa, Rhizaria, Straminipila, Chlorophyta). Analyses based on predicted operational taxonomical units as well as taxonomical compositions revealed no differences between communities in high CO2 mesocosms (~ 760 μatm) and those exposed to present-day CO2 conditions. Observed shifts in the planktonic community composition were mainly related to seasonal changes in temperature and nutrients. Furthermore, based on our investigations, the elevated CO2 did not affect the intraspecific diversity of the most common mesozooplankter, the calanoid copepod Pseudocalanus acuspes. Nevertheless, accompanying studies found temporary effects attributed to a raise in CO2. Differences in taxa composition between the CO2 treatments could, however, only be observed in a specific period of the experiment. Based on our genetic investigations, no compositional long-term shifts of the plankton communities exposed to elevated CO2 conditions were observed. Thus, we conclude that the compositions of planktonic communities, especially those in coastal areas, remain rather unaffected by increased CO2.

  15. Brain plasticity and recovery of cognitive functions

    Directory of Open Access Journals (Sweden)

    Anja Čuš

    2011-10-01

    Full Text Available Through its capacity of plastic changes, the adult brain enables successful dealing with new demands of everyday life and recovery after an acquired brain damage either spontaneously or by the help of rehabilitation interventions. Studies which explored the effects of cognitive training in the normal population report on different types of changes in the performance of cognitive tasks as well as different types of changes in brain activation patterns.Following practice, brain activation can change in its extent, intensity or location, while cognitive processes can become more efficient or can be replaced by different processes.After acquired brain damage plastic changes are somewhat different. After the injury, the damaged brain area can either gradually regain its previous function, or different brain regions are recruited to perform that function.Studies of spontaneous and guided recovery of cognitive functions have revealed both types of plastic changes that follow each other, as well as significant correlations between these changes and improvement on the behavioural level.

  16. Modulation of synaptic plasticity by stress hormone associates with plastic alteration of synaptic NMDA receptor in the adult hippocampus.

    Directory of Open Access Journals (Sweden)

    Yiu Chung Tse

    Full Text Available Stress exerts a profound impact on learning and memory, in part, through the actions of adrenal corticosterone (CORT on synaptic plasticity, a cellular model of learning and memory. Increasing findings suggest that CORT exerts its impact on synaptic plasticity by altering the functional properties of glutamate receptors, which include changes in the motility and function of α-amino-3-hydroxy-5-methylisoxazole-4-propionic acid subtype of glutamate receptor (AMPAR that are responsible for the expression of synaptic plasticity. Here we provide evidence that CORT could also regulate synaptic plasticity by modulating the function of synaptic N-methyl-D-aspartate receptors (NMDARs, which mediate the induction of synaptic plasticity. We found that stress level CORT applied to adult rat hippocampal slices potentiated evoked NMDAR-mediated synaptic responses within 30 min. Surprisingly, following this fast-onset change, we observed a slow-onset (>1 hour after termination of CORT exposure increase in synaptic expression of GluN2A-containing NMDARs. To investigate the consequences of the distinct fast- and slow-onset modulation of NMDARs for synaptic plasticity, we examined the formation of long-term potentiation (LTP and long-term depression (LTD within relevant time windows. Paralleling the increased NMDAR function, both LTP and LTD were facilitated during CORT treatment. However, 1-2 hours after CORT treatment when synaptic expression of GluN2A-containing NMDARs is increased, bidirectional plasticity was no longer facilitated. Our findings reveal the remarkable plasticity of NMDARs in the adult hippocampus in response to CORT. CORT-mediated slow-onset increase in GluN2A in hippocampal synapses could be a homeostatic mechanism to normalize synaptic plasticity following fast-onset stress-induced facilitation.

  17. 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.

  18. Predictors of Readmission after Inpatient Plastic Surgery

    Directory of Open Access Journals (Sweden)

    Umang Jain

    2014-03-01

    Full Text Available Background Understanding risk factors that increase readmission rates may help enhance patient education and set system-wide expectations. We aimed to provide benchmark data on causes and predictors of readmission following inpatient plastic surgery. Methods The 2011 National Surgical Quality Improvement Program dataset was reviewed for patients with both "Plastics" as their recorded surgical specialty and inpatient status. Readmission was tracked through the "Unplanned Readmission" variable. Patient characteristics and outcomes were compared using chi-squared analysis and Student's t-tests for categorical and continuous variables, respectively. Multivariate regression analysis was used for identifying predictors of readmission. Results A total of 3,671 inpatient plastic surgery patients were included. The unplanned readmission rate was 7.11%. Multivariate regression analysis revealed a history of chronic obstructive pulmonary disease (COPD (odds ratio [OR], 2.01; confidence interval [CI], 1.12-3.60; P=0.020, previous percutaneous coronary intervention (PCI (OR, 2.69; CI, 1.21-5.97; P=0.015, hypertension requiring medication (OR, 1.65; CI, 1.22-2.24; P<0.001, bleeding disorders (OR, 1.70; CI, 1.01-2.87; P=0.046, American Society of Anesthesiologists (ASA class 3 or 4 (OR, 1.57; CI, 1.15-2.15; P=0.004, and obesity (body mass index ≥30 (OR, 1.43; CI, 1.09-1.88, P=0.011 to be significant predictors of readmission. Conclusions Inpatient plastic surgery has an associated 7.11% unplanned readmission rate. History of COPD, previous PCI, hypertension, ASA class 3 or 4, bleeding disorders, and obesity all proved to be significant risk factors for readmission. These findings will help to benchmark inpatient readmission rates and manage patient and hospital system expectations.

  19. 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.

  20. 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

  1. 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...

  2. Learning about the Types of Plastic Wastes: Effectiveness of Inquiry Learning Strategies

    Science.gov (United States)

    So, Wing-Mui Winnie; Cheng, Nga-Yee Irene; Chow, Cheuk-Fai; Zhan, Ying

    2016-01-01

    This study aims to examine the impacts of the inquiry learning strategies employed in a "Plastic Education Project" on primary students' knowledge, beliefs and intended behaviour in Hong Kong. Student questionnaires and a test on plastic types were adopted for data collection. Results reveal that the inquiry learning strategies…

  3. Effect of pond depth and lining plastic color on growth and nitrogen ...

    African Journals Online (AJOL)

    Thus, this study evaluated the effect of pond depth and lining plastic colors on nitrogen fixing capacity of Anabaena species strain E3. Factorial combinations of four pond lining plastic colors and two depths were laid out in a complete randomized design with three replications. The ANOVA results revealed that the 20 cm ...

  4. 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

  5. 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...

  6. Developmental plasticity: Friend or foe?

    Science.gov (United States)

    Michels, Karin B

    2017-01-01

    Developmental plasticity - the concept that adaptation to changing and unfavorable environmental conditions are possible but may come at the price of compromised health potentials - has evolutionary grounding as it facilitates survival but dissents with fundamental evolutionary principles in that it may advance the lesser fit. It is an important cornerstone of the Developmental Origins of Health and Disease (DOHaD). Unlike evolutionary adaptation developmental plasticity may be short-lived and restricted to one or few generations and inheritance is uncertain. Potential mechanisms include epigenetic modifications adopted in utero which may not transmit to the next generation; future insights may allow adjustments of the outcomes of developmental plasticity.

  7. Radiation damage in plastic scintillators

    International Nuclear Information System (INIS)

    Majewski, S.

    1990-01-01

    Results of radiation damage studies in plastic scintillators are reviewed and critically analyzed from the point of view of applications of plastic scintillators in calorimetric detectors for the SSC. Damage to transmission and to fluorescent yield in different conditions is discussed. New directions in R ampersand D are outlined. Several examples are given of the most recent data on the new scintillating materials made with old and new plastics and fluors, which are exhibiting significantly improved radiation resistance. With a present rate of a vigorous R D programme, the survival limits in the vicinity of 100 MRad seem to be feasible within a couple of years

  8. Plastics recycling: challenges and opportunities

    OpenAIRE

    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 pro...

  9. Recycling of Reinforced Plastics

    Science.gov (United States)

    Adams, R. D.; Collins, Andrew; Cooper, Duncan; Wingfield-Digby, Mark; Watts-Farmer, Archibald; Laurence, Anna; Patel, Kayur; Stevens, Mark; Watkins, Rhodri

    2014-02-01

    This work has shown is that it is possible to recycle continuous and short fibre reinforced thermosetting resins while keeping almost the whole of the original material, both fibres and matrix, within the recyclate. By splitting, crushing hot or cold, and hot forming, it is possible to create a recyclable material, which we designate a Remat, which can then be used to remanufacture other shapes, examples of plates and tubes being demonstrated. Not only can remanufacturing be done, but it has been shown that over 50 % of the original mechanical properties, such as the E modulus, tensile strength, and interlaminar shear strength, can be retained. Four different forms of composite were investigated, a random mat Glass Fibre Reinforced Plastic (GFRP) bathroom component and boat hull, woven glass and carbon fibre cloth impregnated with an epoxy resin, and unidirectional carbon fibre pre-preg. One of the main factors found to affect composite recyclability was the type of resin matrix used in the composite. Thermoset resins tested were shown to have a temperature range around the Glass Transition Temperature (Tg) where they exhibit ductile behaviour, hence aiding reforming of the material. The high-grade carbon fibre prepreg was found to be less easy to recycle than the woven of random fibre laminates. One method of remanufacturing was by heating the Remat to above its glass transition temperature, bending it to shape, and then cooling it. However, unless precautions are taken, the geometric form may revert. This does not happen with the crushed material.

  10. Wood plastic combination

    International Nuclear Information System (INIS)

    Cunanan, S.A.; Bonoan, L.S.; Verceluz, F.P.; Azucena, E.A.

    1976-03-01

    The purpose of this study is to improve the physical and mechaniproperties of local inferior quality wood species by radiation-induced graft polymerization with plastic monomers. The process involves the following: 1) Preparation of sample; 2) Impregnation of sample with the monomers; 3) Irradiation of the impregnated sample with the use of 20,000 curie Co-60 as gamma-source; 4) Drying of irradiated sample to remove the unpolymerized monomer. Experimentation on different wood species were undertaken and the results given. From the results obtained, it can be concluded that the monomers systems MMA, MMA-USP, and styrene-USP are suitable for graft polymerization with the wood species almon, apitong, bagtikan, mayapis, red lauan, and tanguile. This is shown by their maximum conversion value which range from 86% to 96% with the optimum dose range of 1 to 2 Mrads. However, in the application of WPC process, properties that are required in a given wood product must be considered, thus aid in the selection of the monomer system to be used with a particular wood species. Some promising applications of WPC is in the manufacture of picker sticks, shuttles, and bobbins for the textile industry. However, there is a need for a pilot plant scale study so that an economic assessment of the commercial feasibility of this process can be made

  11. Helene: A Plastic Model

    Science.gov (United States)

    Umurhan, O. M.; Moore, J. M.; Howard, A. D.; Schenk, P.; White, O. L.

    2014-12-01

    Helene, the Saturnian L4 Trojan satellite co-orbiting Dionne and sitting within the E-ring, possesses an unusual morphology characteristic of broad km-scale basins and depressions and a generally smooth surface patterned with streaks and grooves which are indicative of non-typical mass transport. Elevation angles do not appear to exceed 10o at most. The nature and origin of the surface materials forming these grooved patterns is unknown. Given the low surface gravity (plastic-like flow like a Bingham fluid, we setup and test a number of likely scenarios to explain the observations. The numerical results qualitatively indicate that treating the mass-wasting materials as a Bingham material reproduces many of the qualitative features observed. We also find that in those simulations in which accretion is concomitant with Bingham mass-wasting, the long time-evolution of the surface flow shows intermittency in the total surface activity (defined as total surface integral of the absolute magnitude of the mass-flux). Detailed analyses identify the locations where this activity is most pronounced and we will discuss these and its implications in further detail.

  12. Plastic Muscles TM as lightweight, low voltage actuators and sensors

    Science.gov (United States)

    Bennett, Matthew; Leo, Donald; Duncan, Andrew

    2008-03-01

    Using proprietary technology, Discover Technologies has developed ionomeric polymer transducers that are capable of long-term operation in air. These "Plastic Muscle TM" transducers are useful as soft distributed actuators and sensors and have a wide range of applications in the aerospace, robotics, automotive, electronics, and biomedical industries. Discover Technologies is developing novel fabrication methods that allow the Plastic Muscles TM to be manufactured on a commercial scale. The Plastic Muscle TM transducers are capable of generating more than 0.5% bending strain at a peak strain rate of over 0.1 %/s with a 3 V input. Because the Plastic Muscles TM use an ionic liquid as a replacement solvent for water, they are able to operate in air for long periods of time. Also, the Plastic Muscles TM do not exhibit the characteristic "back relaxation" phenomenon that is common in water-swollen devices. The elastic modulus of the Plastic Muscle TM transducers is estimated to be 200 MPa and the maximum generated stress is estimated to be 1 MPa. Based on these values, the maximum blocked force at the tip of a 6 mm wide, 35 mm long actuator is estimated to be 19 mN. Modeling of the step response with an exponential series reveals nonlinearity in the transducers' behavior.

  13. Plastic-covered agriculture forces the regional climate to change

    Science.gov (United States)

    Yang, D.; Chen, J.; Chen, X.; Cao, X.

    2016-12-01

    The practice of plastic-covered agriculture as a solution to moderate the dilemma of global food shortage, meanwhile, brings great pressure to the local environment. This research was conducted to reveal the impacts of plastic-covered agritulture on regional climate change by experimenting in a plastic greenhouse (PG) dominated area - Weifang district, Shandong province, China. Based on a new plastic greenhouse index (PGI) proposed in this study, we reconstructed the spatial distribution of PG across 1995-2015 in the study area. With that, land surface temperature (LST) dataset combined with surface evapotranspiration, surface reflectance and precipitation data, was applied to the probe of PG's climatic impacts. Results showed that PG, in the study area, has experienced a striking spatial expansion during the past 20 years, and more important, the expansion correlated strongly to the local climate change. It showed that the annual precipitation, in the study area, decreased during these years, which constrasts to a slightly increasing trend of the adjacent districts without PG construction. In addition, resulting from the greenhouse effect, PG area presented a harsher increase of surface temperature compared to the non-PG areas. Our study also telled that the evapotranspiration of PG area has been largely cutted down ascribing to the gas tightness of plastic materials, showing a decline around 40%. This indicates a way that the development of plastic-covered agriculture may contribute to the change of the local climate.

  14. Revealing Rembrandt

    Directory of Open Access Journals (Sweden)

    Andrew J Parker

    2014-04-01

    Full Text Available The power and significance of artwork in shaping human cognition is self-evident. The starting point for our empirical investigations is the view that the task of neuroscience is to integrate itself with other forms of knowledge, rather than to seek to supplant them. In our recent work, we examined a particular aspect of the appreciation of artwork using present-day functional magnetic resonance imaging (fMRI. Our results emphasised the continuity between viewing artwork and other human cognitive activities. We also showed that appreciation of a particular aspect of artwork, namely authenticity, depends upon the co-ordinated activity between the brain regions involved in multiple decision making and those responsible for processing visual information. The findings about brain function probably have no specific consequences for understanding how people respond to the art of Rembrandt in comparison with their response to other artworks. However, the use of images of Rembrandt’s portraits, his most intimate and personal works, clearly had a significant impact upon our viewers, even though they have been spatially confined to the interior of an MRI scanner at the time of viewing. Neuroscientific studies of humans viewing artwork have the capacity to reveal the diversity of human cognitive responses that may be induced by external advice or context as people view artwork in a variety of frameworks and settings.

  15. ASSESSMENT OF PLASTIC FLOWS AND STOCKS IN SERBIA USING MATERIAL FLOW ANALYSIS

    Directory of Open Access Journals (Sweden)

    Goran Vujić

    2010-01-01

    Full Text Available Material flow analysis (MFA was used to assess the amounts of plastic materials flows and stocks that are annually produced, consumed, imported, exported, collected, recycled, and disposed in the landfills in Serbia. The analysis revealed that approximatelly 269,000 tons of plastic materials are directly disposed in uncontrolled landfills in Serbia without any preatretment, and that siginificant amounts of these materials have already accumulated in the landfills. The substantial amounts of landfilled plastics represent not only a loss of valuable recourses, but also pose a seriuos treath to the environment and human health, and if the trend of direct plastic landfilling is continued, Serbia will face with grave consecequnces.

  16. Crystal plasticity study of single crystal tungsten by indentation tests

    International Nuclear Information System (INIS)

    Yao, Weizhi

    2012-01-01

    Owing to its favorable material properties, tungsten (W) has been studied as a plasma-facing material in fusion reactors. Experiments on W heating in plasma sources and electron beam facilities have shown an intense micro-crack formation at the heated surface and sub-surface. The cracks go deep inside the irradiated sample, and often large distorted areas caused by local plastic deformation are present around the cracks. To interpret the crack-induced microscopic damage evolution process in W, one needs firstly to understand its plasticity on a single grain level, which is referred to as crystal plasticity. In this thesis, the crystal plasticity of single crystal tungsten (SCW) has been studied by spherical and Berkovich indentation tests and the finite element method with a crystal plasticity model. Appropriate values of the material parameters included in the crystal plasticity model are determined by fitting measured load-displacement curves and pile-up profiles with simulated counterparts for spherical indentation. The numerical simulations reveal excellent agreement with experiment. While the load-displacement curves and the deduced indentation hardness exhibit little sensitivity to the indented plane at small indentation depths, the orientation of slip directions within the crystals governs the development of deformation hillocks at the surface. It is found that several factors like friction, indentation depth, active slip systems, misoriented crystal orientation, misoriented sample surface and azimuthal orientation of the indenter can affect the indentation behavior of SCW. The Berkovich indentation test was also used to study the crystal plasticity of SCW after deuterium irradiation. The critical load (pop-in load) for triggering plastic deformation under the indenter is found to depend on the crystallographic orientation. The pop-in loads decrease dramatically after deuterium plasma irradiation for all three investigated crystallographic planes.

  17. Energy recovery from plastic wastes

    Energy Technology Data Exchange (ETDEWEB)

    Baur, A; Atzger, J

    1983-07-01

    The conversion of plastic wastes to energy is suggested as a practicable and advantageous alternative to recycling. A two-stage pilot gasification plant for the pyrolysis of wastes is described and the utilization of the resulting fuel gas discussed.

  18. Plasticity and creep of metals

    CERN Document Server

    Rusinko, Andrew

    2011-01-01

    Here is a systematic presentation of the postulates, theorems and principles of mathematical theories of plasticity and creep in metals, and their applications. Special attention is paid to analysis of the advantages and shortcomings of the classical theories.

  19. Neuromodulation, development and synaptic plasticity.

    Science.gov (United States)

    Foehring, R C; Lorenzon, N M

    1999-03-01

    We discuss parallels in the mechanisms underlying use-dependent synaptic plasticity during development and long-term potentiation (LTP) and long-term depression (LTD) in neocortical synapses. Neuromodulators, such as norepinephrine, serotonin, and acetylcholine have also been implicated in regulating both developmental plasticity and LTP/LTD. There are many potential levels of interaction between neuromodulators and plasticity. Ion channels are substrates for modulation in many cell types. We discuss examples of modulation of voltage-gated Ca2+ channels and Ca(2+)-dependent K+ channels and the consequences for neocortical pyramidal cell firing behaviour. At the time when developmental plasticity is most evident in rat cortex, the substrate for modulation is changing as the densities and relative proportions of various ion channels types are altered during ontogeny. We discuss examples of changes in K+ and Ca2+ channels and the consequence for modulation of neuronal activity.

  20. WEATHERABILITY OF ENHANCED DEGRADABLE PLASTICS

    Science.gov (United States)

    The main objective of this study was to assess the performance and the asociated variability of several selected enhanced degradable plastic materials under a variety of different exposure conditions. Other objectives were to identify the major products formed during degradation ...

  1. Experimental investigation on the properties of concrete containing post-consumer plastic waste as coarse aggregate replacement

    Directory of Open Access Journals (Sweden)

    Zasiah TAFHEEM

    2018-03-01

    Full Text Available The consumption of various forms of plastic has been increased in recent days due to the boost in industrialization and other human activities. Most of the plastic wastes are abandoned and require large landfill area for storage. More importantly, the low biodegradability of plastic poses a serious threat to environment protection issue. Various methods have been followed for the disposal of plastic in an attempt to reduce the negative impact of the plastic on the environment. Recently, various types of plastic have been incorporated in concrete to minimize the exposure of plastic to the environment. The aim of this study is to investigate the properties of concrete containing polyethylene terephthalate (PET, and high density polyethylene (HDPE plastic that were used as partial replacement of coarse aggregate (CA. In this study, four compositions of stone aggregate(S: plastic waste ratios have been used by volume basis: 100% S: 0% Plastic (control concrete, 90% S: 10% PET, 90% S: 10% HDPE, and 90% S: 5% PET+5% HDPE. The effects of waste plastic addition on the mechanical properties of concrete are presented in this paper. Test results reveal that minimum reduction in compressive strength has been found 35% in case of 10% PET plastic replaced concrete whereas splitting tensile strength for 10% PET replaced concrete has been increased by 21% while compared to control concrete. In addition, fresh unit weight of concrete containing plastic waste has been decreased by 4% in comparison to control concrete.

  2. Biocide Usage in Plastic Products

    OpenAIRE

    Kavak, Nergizhan; Çakır, Ayşegül; Koltuk, Fatmagül; Uzun, Utku

    2015-01-01

    People’s demand of improving their life quality caused to the term of hygiene become popular and increased the tendency to use more reliable and healthy products. This tendency makes the continuous developments in the properties of the materials used in manufactured goods compulsory. It is possible to create anti-bacterial plastic products by adding biocidal additives to plastic materials which have a wide-range of application in the areas such as health (medicine), food and many other indust...

  3. Interhemispheric plasticity in humans.

    Science.gov (United States)

    Hortobágyi, Tibor; Richardson, Sarah Pirio; Lomarev, Mikhael; Shamim, Ejaz; Meunier, Sabine; Russman, Heike; Dang, Nguyet; Hallett, Mark

    2011-07-01

    Chronic unimanual motor practice increases the motor output not only in the trained but also in the nonexercised homologous muscle in the opposite limb. We examined the hypothesis that adaptations in motor cortical excitability of the nontrained primary motor cortex (iM1) and in interhemispheric inhibition from the trained to the nontrained M1 mediate this interlimb cross education. Healthy, young volunteers (n=12) performed 1000 submaximal voluntary contractions (MVC) of the right first dorsal interosseus (FDI) at 80% MVC during 20 sessions. Trained FDI's MVC increased 49.9%, and the untrained FDI's MVC increased 28.1%. Although corticospinal excitability in iM1, measured with transcranial magnetic stimulation (TMS) before and after every fifth session, increased 6% at rest, these changes, as those in intracortical inhibition and facilitation, did not correlate with cross education. When weak and strong TMS of iM1 were delivered on a background of a weak and strong muscle contraction, respectively, of the right FDI, excitability of iM1 increased dramatically after 20 sessions. Interhemispheric inhibition decreased 8.9% acutely within sessions and 30.9% chronically during 20 sessions and these chronic reductions progressively became more strongly associated with cross education. There were no changes in force or TMS measures in the trained group's left abductor minimi digiti and there were no changes in the nonexercising control group (n=8). The findings provide the first evidence for plasticity of interhemispheric connections to mediate cross education produced by a simple motor task.

  4. Unified pre- and postsynaptic long-term plasticity enables reliable and flexible learning.

    Science.gov (United States)

    Costa, Rui Ponte; Froemke, Robert C; Sjöström, P Jesper; van Rossum, Mark Cw

    2015-08-26

    Although it is well known that long-term synaptic plasticity can be expressed both pre- and postsynaptically, the functional consequences of this arrangement have remained elusive. We show that spike-timing-dependent plasticity with both pre- and postsynaptic expression develops receptive fields with reduced variability and improved discriminability compared to postsynaptic plasticity alone. These long-term modifications in receptive field statistics match recent sensory perception experiments. Moreover, learning with this form of plasticity leaves a hidden postsynaptic memory trace that enables fast relearning of previously stored information, providing a cellular substrate for memory savings. Our results reveal essential roles for presynaptic plasticity that are missed when only postsynaptic expression of long-term plasticity is considered, and suggest an experience-dependent distribution of pre- and postsynaptic strength changes.

  5. Physicochemical properties of sugar palm starch film: Effect of concentration and plasticizer type

    Science.gov (United States)

    Prasetyo, D. J.; Apriyana, W.; Jatmiko, T. H.; Hernawan; Hayati, S. N.; Rosyida, V. T.; Pranoto, Y.; Poeloengasih, C. D.

    2017-07-01

    In order to find the best formula for capsule shell production, this present work dealt with exploring physicochemical properties of sugar palm (Arenga pinnata) starch film as a function of different kinds and various concentrations of plasticizers. The films were prepared by casting method at different formula: starch 9-11%, glycerol or sorbitol 35-45% and polyethylene-glycol 400 (PEG 400) 5-9%. Appearance, thickness, retraction ratio, moisture content, swelling behavior and solubility of the film in water were analyzed. Both glycerol and sorbitol are compatible with starch matrix. On the contrary, PEG 400 did not form a film with suitable characteristics. The result reveals that glycerol- and sorbitol-plasticized films appeared translucent, homogenous, smooth and slightly brown in all formulas. Different type and concentration of plasticizers altered the physicochemical of film in different ways. The sorbitol-plasticized film had lower moisture content (≤ 10%) than that of glycerol-plasticized film (≥ 18%). In contrast, film plasticized with sorbitol showed higher solubility in water (28-35%) than glycerol-plasticized film (22-28%). As the concentration of both plasticizers increased, there was an increasing tendency on thickness and solubility in water. Conversely, retraction ratio and swelling degree decreased when both plasticizers concentration increased. In conclusion, the sorbitol-plasticized film showed a potency to be developed as hard capsule material.

  6. Increasing frequency of plastic particles ingested by seabirds in the subarctic North Pacific

    Science.gov (United States)

    Robards, Martin D.; Piatt, John F.; Wohl, Kenton D.

    1995-01-01

    We examined gut contents of 1799 seabirds comprising 24 species collected in 1988-1990 to assess the types and quantities of plastic particles ingested by seabirds in the subarctic waters of Alaska. Of the 15 species found to ingest plastic, most were surface-feeders (shearwaters, petrels, gulls) or plankton-feeding divers (auklets, puffins). Of 4417 plastic particles examined, 76% were industrial pellets and 21% were fragments of ‘user’ plastic. Ingestion rates varied geographically, but no trends were evident and rates of plastic ingestion varied far more among species within areas than within species among areas. Comparison with similar data from 1968 seabirds comprising 37 species collected in 1969-1977 revealed that plastic ingestion by seabirds has increased significantly during the 10–15-year interval between studies. This was demonstrated by: (i) an increase in the total number of species ingesting plastic; (ii) an increase in the frequency of occurrence of plastic particles within species that ingested plastic; and, (iii) an increase in the mean number of plastic particles ingested by individuals of those species.

  7. ARE PLASTIC GROCERY BAGS SACKING THE ENVIRONMENT?

    OpenAIRE

    Mangal Gogte

    2009-01-01

    This paper is oriented on analysis impacts of plastic bags on environment. In this paper is analyzed did plastic bags are so harmful, and what are the main ingredients of it. One part of this paper is oriented on effects of plastic bags and management of their usage. There is also made comparative analysis between impacts of plastic and paper bags on environment.

  8. 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...

  9. 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...

  10. Properties of plasticized composite films prepared from nanofibrillated cellulose and birch wood xylan

    DEFF Research Database (Denmark)

    Hansen, Natanya Majbritt Louie; Blomfeldt, Thomas O. J.; Hedenqvist, Mikael S.

    2012-01-01

    was combined with nanofibrillated cellulose (NFC) and films were cast with and without glycerol, sorbitol or methoxypolyethylene glycol (MPEG) as plasticizers. Microscopy revealed some NFC agglomeration in the composite films as well as a layered nanocellulose structure. Equilibrium moisture content...... in plasticized films increased with glycerol content but was independent of xylan:NFC ratio in unplasticized films. Sorbitol- and MPEG-plasticized films showed equilibrium moisture contents of approximately 10 wt% independent of plasticizer content. Tensile testing revealed increases in tensile strength...... with increased NFC content in the xylan:NFC composition range from 50:50 to 80:20 and plasticizer addition generally provided less brittle films. The oxygen permeability of unplasticized xylan-NFC films fell into a range which was similar to that for previously measured pure NFC films and was statistically...

  11. Plastic zonder olie : lesmodule voor nieuwe scheikunde

    OpenAIRE

    Langejan, B.; Klein Douwel, C.; Horst, ter, J.J.; Tijdink, K.; Marle, van, N.; Klaasen, P.; Coolen, R.; Assenbergh, van, P.; Sijbers, J.P.J.; Mast, A.

    2013-01-01

    Lesmodule voor nieuwe scheikunde voor leerlingen uit 5 en 6 vwo. Bioplastics worden gemaakt uit natuurlijke grondstoffen. Als ze de synthetische plastics vervangen kan de voorraad aardolie ontzien worden. Omdat veel bioplastics afbreekbaar zijn, kan ook de berg plastic afval krimpen. Maar zijn bioplastics in staat om ons de reguliere plastics te doen vergeten? Hoe maken we bioplastics met dezelfde veelzijdige eigenschappen als plastic? Waar komen de uiteenlopende eigenschappen van plastics ei...

  12. Elimination of Plastic Polymers in Natural Environments

    OpenAIRE

    Ramirez-Ekner, Sofia; Bidstrup, Marie Juliane Svea; Brusen, Nicklas Hald; Rugaard-Morgan, Zsa-Zsa Sophie Oona Ophelia

    2017-01-01

    Plastic production and consumption continues to rise and subsequently plastic waste continues to accumulates in natural environments, causing harm to ecosystems.The aim of this paper was to come up with a way to utilize organisms, that have been identified to produce plastic degrading enzymes, as a waste disposal technology. This review includes accounts of plastic production rates, the occurrence of plastic in natural environments and the current waste management systems to create an underst...

  13. Black plastics: Linear and circular economies, hazardous additives and marine pollution.

    Science.gov (United States)

    Turner, Andrew

    2018-05-17

    Black products constitute about 15% of the domestic plastic waste stream, of which the majority is single-use packaging and trays for food. This material is not, however, readily recycled owing to the low sensitivity of black pigments to near infrared radiation used in conventional plastic sorting facilities. Accordingly, there is mounting evidence that the demand for black plastics in consumer products is partly met by sourcing material from the plastic housings of end-of-life waste electronic and electrical equipment (WEEE). Inefficiently sorted WEEE plastic has the potential to introduce restricted and hazardous substances into the recyclate, including brominated flame retardants (BFRs), Sb, a flame retardant synergist, and the heavy metals, Cd, Cr, Hg and Pb. The current paper examines the life cycles of single-use black food packaging and black plastic WEEE in the context of current international regulations and directives and best practices for sorting, disposal and recycling. The discussion is supported by published and unpublished measurements of restricted substances (including Br as a proxy for BFRs) in food packaging, EEE plastic goods and non-EEE plastic products. Specifically, measurements confirm the linear economy of plastic food packaging and demonstrate a complex quasi-circular economy for WEEE plastic that results in significant and widespread contamination of black consumer goods ranging from thermos cups and cutlery to tool handles and grips, and from toys and games to spectacle frames and jewellery. The environmental impacts and human exposure routes arising from WEEE plastic recycling and contamination of consumer goods are described, including those associated with marine pollution. Regarding the latter, a compilation of elemental data on black plastic litter collected from beaches of southwest England reveals a similar chemical signature to that of contaminated consumer goods and blended plastic WEEE recyclate, exemplifying the pervasiveness

  14. 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.

  15. Plasticity characteristic obtained by indentation

    International Nuclear Information System (INIS)

    Milman, Yu V

    2008-01-01

    A dimensionless parameter δ H = ε p /ε t (where ε p and ε t are the average values of plastic and total deformation of material on the contact area indenter-specimen) may be used as the plasticity characteristic of materials, which made it possible to characterize the plasticity of materials that are brittle in standard mechanical tests. δ H may be calculated from the values of microhardness HM, Young's modulus E and Poisson's ratio ν. In instrumented indentation the plasticity characteristic δ A = A p /A t (A p and A t are the work of plastic and total deformation during indentation) may be calculated. δ A ∼ δ H for materials with δ H > 0.5, i.e. for all metals and the majority of ceramic materials. In this case, the theoretical equation δ A ∼ δ H = 1-10.2 · (1 - ν - 2ν 2 )(HM/E) is satisfied in experiments with the Berkovich indenter. The influence of the temperature and structural parameters (dislocation density and grain size including nanostructured materials) on δ H is discussed

  16. Mechanisms of GABAergic Homeostatic Plasticity

    Directory of Open Access Journals (Sweden)

    Peter Wenner

    2011-01-01

    Full Text Available Homeostatic plasticity ensures that appropriate levels of activity are maintained through compensatory adjustments in synaptic strength and cellular excitability. For instance, excitatory glutamatergic synapses are strengthened following activity blockade and weakened following increases in spiking activity. This form of plasticity has been described in a wide array of networks at several different stages of development, but most work and reviews have focussed on the excitatory inputs of excitatory neurons. Here we review homeostatic plasticity of GABAergic neurons and their synaptic connections. We propose a simplistic model for homeostatic plasticity of GABAergic components of the circuitry (GABAergic synapses onto excitatory neurons, excitatory connections onto GABAergic neurons, cellular excitability of GABAergic neurons: following chronic activity blockade there is a weakening of GABAergic inhibition, and following chronic increases in network activity there is a strengthening of GABAergic inhibition. Previous work on GABAergic homeostatic plasticity supports certain aspects of the model, but it is clear that the model cannot fully account for some results which do not appear to fit any simplistic rule. We consider potential reasons for these discrepancies.

  17. Neurogenomic mechanisms of social plasticity.

    Science.gov (United States)

    Cardoso, Sara D; Teles, Magda C; Oliveira, Rui F

    2015-01-01

    Group-living animals must adjust the expression of their social behaviour to changes in their social environment and to transitions between life-history stages, and this social plasticity can be seen as an adaptive trait that can be under positive selection when changes in the environment outpace the rate of genetic evolutionary change. Here, we propose a conceptual framework for understanding the neuromolecular mechanisms of social plasticity. According to this framework, social plasticity is achieved by rewiring or by biochemically switching nodes of a neural network underlying social behaviour in response to perceived social information. Therefore, at the molecular level, it depends on the social regulation of gene expression, so that different genomic and epigenetic states of this brain network correspond to different behavioural states, and the switches between states are orchestrated by signalling pathways that interface the social environment and the genotype. Different types of social plasticity can be recognized based on the observed patterns of inter- versus intra-individual occurrence, time scale and reversibility. It is proposed that these different types of social plasticity rely on different proximate mechanisms at the physiological, neural and genomic level. © 2015. Published by The Company of Biologists Ltd.

  18. Smartphones and the plastic surgeon.

    Science.gov (United States)

    Al-Hadithy, Nada; Ghosh, Sudip

    2013-06-01

    Surgical trainees are facing limited training opportunities since the introduction of the European Working Time Directive. Smartphone sales are increasing and have usurped computer sales for the first time. In this context, smartphones are an important portable reference and educational tool, already in the possession of the majority of surgeons in training. Technology in the palm of our hands has led to a revolution of accessible information for the plastic surgery trainee and surgeon. This article reviews the uses of smartphones and applications for plastic surgeons in education, telemedicine and global health. A comprehensive guide to existing and upcoming learning materials and clinical tools for the plastic surgeon is included. E-books, podcasts, educational videos, guidelines, work-based assessment tools and online logbooks are presented. In the limited resource setting of modern clinical practice, savvy plastic surgeons can select technological tools to democratise access to education and best clinical care. Copyright © 2013 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved.

  19. Plasticity-Related Gene Expression During Eszopiclone-Induced Sleep.

    Science.gov (United States)

    Gerashchenko, Dmitry; Pasumarthi, Ravi K; Kilduff, Thomas S

    2017-07-01

    Experimental evidence suggests that restorative processes depend on synaptic plasticity changes in the brain during sleep. We used the expression of plasticity-related genes to assess synaptic plasticity changes during drug-induced sleep. We first characterized sleep induced by eszopiclone in mice during baseline conditions and during the recovery from sleep deprivation. We then compared the expression of 18 genes and two miRNAs critically involved in synaptic plasticity in these mice. Gene expression was assessed in the cerebral cortex and hippocampus by the TaqMan reverse transcription polymerase chain reaction and correlated with sleep parameters. Eszopiclone reduced the latency to nonrapid eye movement (NREM) sleep and increased NREM sleep amounts. Eszopiclone had no effect on slow wave activity (SWA) during baseline conditions but reduced the SWA increase during recovery sleep (RS) after sleep deprivation. Gene expression analyses revealed three distinct patterns: (1) four genes had higher expression either in the cortex or hippocampus in the group of mice with increased amounts of wakefulness; (2) a large proportion of plasticity-related genes (7 out of 18 genes) had higher expression during RS in the cortex but not in the hippocampus; and (3) six genes and the two miRNAs showed no significant changes across conditions. Even at a relatively high dose (20 mg/kg), eszopiclone did not reduce the expression of plasticity-related genes during RS period in the cortex. These results indicate that gene expression associated with synaptic plasticity occurs in the cortex in the presence of a hypnotic medication. © Sleep Research Society 2017. Published by Oxford University Press on behalf of the Sleep Research Society. All rights reserved. For permissions, please e-mail journals.permissions@oup.com.

  20. Exercise and plasticize the brain

    DEFF Research Database (Denmark)

    Mala, Hana; Wilms, Inge

    Neuroscientific studies continue to shed light on brain’s plasticity and its innate mechanisms to recover. The recovery process includes re-wiring of the existing circuitry, establishment of new connections, and recruitment of peri-lesional and homologous areas in the opposite hemisphere....... The plasticity of the brain can be stimulated and enhanced through training, which serves as a fundamental element of neurorehabilitative strategies. For instance, intensive cognitive and physical training promote the activation of processes that may help the brain to adapt to new conditions and needs. However...... neurorehabilitation is to understand and define how to stimulate the injured brain to elicit the desired adaptation. Research focuses on uncovering specific elements relevant for training planning and execution in order to create an environment that stimulates and maximizes the exploitation of the brain’s plastic...

  1. Surface properties of beached plastics.

    Science.gov (United States)

    Fotopoulou, Kalliopi N; Karapanagioti, Hrissi K

    2015-07-01

    Studying plastic characteristics in the marine environment is important to better understand interaction between plastics and the environment. In the present study, high-density polyethylene (HDPE), polyethylene terephalate (PET), and polyvinyl chloride (PVC) samples were collected from the coastal environment in order to study their surface properties. Surface properties such as surface functional groups, surface topography, point of zero charge, and color change are important factors that change during degradation. Eroded HDPE demonstrated an altered surface topography and color and new functional groups. Eroded PET surface was uneven, yellow, and occasionally, colonized by microbes. A decrease in Fourier transform infrared (FTIR) peaks was observed for eroded PET suggesting that degradation had occurred. For eroded PVC, its surface became more lamellar and a new FTIR peak was observed. These surface properties were obtained due to degradation and could be used to explain the interaction between plastics, microbes, and pollutants.

  2. The Prism Plastic Calorimeter (PPC)

    CERN Multimedia

    2002-01-01

    This proposal supports two goals: \\\\ \\\\ First goal:~~Demonstrate that current, widely used plastic technologies allow to design Prism Plastic Calorimeter~(PPC) towers with a new ``liquid crystal'' type plastic called Vectra. It will be shown that this technique meets the requirements for a LHC calorimeter with warm liquids: safety, hermeticity, hadronic compensation, resolution and time response. \\\\ \\\\ Second goal:~~Describe how one can design a warm liquid calorimeter integrated into a LHC detector and to list the advantages of the PPC: low price, minimum of mechanical structures, minimum of dead space, easiness of mechanical assembly, accessibility to the electronics, possibility to recirculate the liquid. The absorber and the electronic being outside of the liquid and easily accessible, one has maximum flexibility to define them. \\\\ \\\\ The R&D program, we define here aims at showing the feasibility of these new ideas by building nine towers of twenty gaps and exposing them to electron and hadron beams.

  3. Plastic solidification of radioactive wastes

    International Nuclear Information System (INIS)

    Moriyama, Noboru

    1981-01-01

    Over 20 years have elapsed after the start of nuclear power development, and the nuclear power generation in Japan now exceeds the level of 10,000 MW. In order to meet the energy demands, the problem of the treatment and disposal of radioactive wastes produced in nuclear power stations must be solved. The purpose of the plastic solidification of such wastes is to immobilize the contained radionuclides, same as other solidification methods, to provide the first barrier against their move into the environment. The following matters are described: the nuclear power generation in Japan, the radioactive wastes from LWR plants, the position of plastic solidification, the status of plastic solidification in overseas countries and in Japan, the solidification process for radioactive wastes with polyethylene, and the properties of solidified products, and the leachability of radionuclides in asphalt solids. (J.P.N.)

  4. Diet and cognition: interplay between cell metabolism and neuronal plasticity.

    Science.gov (United States)

    Gomez-Pinilla, Fernando; Tyagi, Ethika

    2013-11-01

    To discuss studies in humans and animals revealing the ability of foods to benefit the brain: new information with regards to mechanisms of action and the treatment of neurological and psychiatric disorders. Dietary factors exert their effects on the brain by affecting molecular events related to the management of energy metabolism and synaptic plasticity. Energy metabolism influences neuronal function, neuronal signaling, and synaptic plasticity, ultimately affecting mental health. Epigenetic regulation of neuronal plasticity appears as an important mechanism by which foods can prolong their effects on long-term neuronal plasticity. The prime focus of the discussion is to emphasize the role of cell metabolism as a mediator for the action of foods on the brain. Oxidative stress promotes damage to phospholipids present in the plasma membrane such as the omega-3 fatty acid docosahexenoic acid, disrupting neuronal signaling. Thus, dietary docosahexenoic acid seems crucial for supporting plasma membrane function, interneuronal signaling, and cognition. The dual action of brain-derived neurotrophic factor in neuronal metabolism and synaptic plasticity is crucial for activating signaling cascades under the action of diet and other environmental factors, using mechanisms of epigenetic regulation.

  5. Plasticity Regulators Modulate Specific Root Traits in Discrete Nitrogen Environments

    Science.gov (United States)

    Gifford, Miriam L.; Banta, Joshua A.; Katari, Manpreet S.; Hulsmans, Jo; Chen, Lisa; Ristova, Daniela; Tranchina, Daniel; Purugganan, Michael D.; Coruzzi, Gloria M.; Birnbaum, Kenneth D.

    2013-01-01

    Plant development is remarkably plastic but how precisely can the plant customize its form to specific environments? When the plant adjusts its development to different environments, related traits can change in a coordinated fashion, such that two traits co-vary across many genotypes. Alternatively, traits can vary independently, such that a change in one trait has little predictive value for the change in a second trait. To characterize such “tunability” in developmental plasticity, we carried out a detailed phenotypic characterization of complex root traits among 96 accessions of the model Arabidopsis thaliana in two nitrogen environments. The results revealed a surprising level of independence in the control of traits to environment – a highly tunable form of plasticity. We mapped genetic architecture of plasticity using genome-wide association studies and further used gene expression analysis to narrow down gene candidates in mapped regions. Mutants in genes implicated by association and expression analysis showed precise defects in the predicted traits in the predicted environment, corroborating the independent control of plasticity traits. The overall results suggest that there is a pool of genetic variability in plants that controls traits in specific environments, with opportunity to tune crop plants to a given environment. PMID:24039603

  6. Constraints on the evolution of phenotypic plasticity

    DEFF Research Database (Denmark)

    Murren, Courtney J; Auld, Josh R.; Callahan, Hilary S

    2015-01-01

    Phenotypic plasticity is ubiquitous and generally regarded as a key mechanism for enabling organisms to survive in the face of environmental change. Because no organism is infinitely or ideally plastic, theory suggests that there must be limits (for example, the lack of ability to produce...... an optimal trait) to the evolution of phenotypic plasticity, or that plasticity may have inherent significant costs. Yet numerous experimental studies have not detected widespread costs. Explicitly differentiating plasticity costs from phenotype costs, we re-evaluate fundamental questions of the limits...... to the evolution of plasticity and of generalists vs specialists. We advocate for the view that relaxed selection and variable selection intensities are likely more important constraints to the evolution of plasticity than the costs of plasticity. Some forms of plasticity, such as learning, may be inherently...

  7. Plasticity Theory of Fillet Welds

    DEFF Research Database (Denmark)

    Hansen, Thomas

    2005-01-01

    a safe and statically admissible stress distribution is established. The plasticity solutions are compared with tests carried out at the Engineering Academy of Denmark, Lyngby, in the early nineties, and old fillet weld tests. The new failure conditions are in very good agreement with the yield load......This paper deals with simple methods for calculation of fillet welds based on the theory of plasticity. In developing the solutions the lower-bound theorem is used. The welding material and parts of the base material are subdivided into triangular regions with homogeneous stress fields; thereby...... tests, but not so good agreement with the old failure load tests....

  8. The Plastic Tension Field Method

    DEFF Research Database (Denmark)

    Hansen, Thomas

    2005-01-01

    This paper describes a calculation method for steel plate girders with transverse web stiffeners subjected to shear. It may be used for predicting the failure load or, as a design method, to determine the optimal amount of internal web stiffeners. The new method is called the plastic tension field...... method. The method is based on the theory of plasticity and is analogous to the so-called diagonal compression field method developed for reinforced concrete beams with transverse stirrups, which is adopted in the common European concrete code (Eurocode 2). Many other theories have been developed...

  9. Preparation of coloured wood plastics

    International Nuclear Information System (INIS)

    Lebedev, V.T.; Filippova, T.G.; Rajchuk, F.Z.

    1977-01-01

    A study has been made into the possibility of using fat, as well as alcohol- and water-soluble dyes for radiation-chemical dying of polymers and plastics filled with wood. The use of fat-soluble azo and anthraquinone dyes permits obtaining intensely colored wood-plastic materials based on methyl methacrylate by way of gamma radiation with doses of up to 3 Mrad. At a dose above 5 Mrad, a marked tarnishing of the dye or a change in color and stains are observed. Dyes in styrene withstand higher radiation doses without any significant destruction

  10. Association between Phthalate Exposure and the Use of Plastic Containers in Shanghai Adults.

    Science.gov (United States)

    Dong, Rui Hua; Zhang, Han; Zhang, Mei Ru; Chen, Jing Si; Wu, Min; Li, Shu Guang; Chen, Bo

    2017-10-01

    Consuming phthalates may be due to the presence of food contact materials, such as plastic containers. In this study, we investigated the association between plastic container use and phthalate exposure in 2,140 Shanghai adults. Participants completed a questionnaire on the frequency of using plastic containers in different scenarios in the previous year (e.g., daily, weekly) and on the consumption of plastic-packaged foods in the previous three days (yes or no). Urinary phthalate metabolites were used to assess the association between phthalate exposure and the use of plastic containers. The metabolites of di-(2-ethylhexyl) phthalate (DEHP) were the most frequently detected in urine. The results revealed that phthalate exposure was associated with consumption of plastic-packaged breakfast or processed food items in the previous three days. The consumption of these two food items had strong synergistic effects on increasing urinary concentrations of most phthalate metabolites. Our results of plastic-packaged breakfast and processed food may be explained by the use of flexible plastic containers, indicating the importance of risk assessment for the application of flexible plastic containers. Copyright © 2017 The Editorial Board of Biomedical and Environmental Sciences. Published by China CDC. All rights reserved.

  11. A First Survey on the Abundance of Plastics Fragments and Particles on Two Sandy Beaches in Kuching, Sarawak, Malaysia

    Science.gov (United States)

    Noik, V. James; Mohd Tuah, P.

    2015-04-01

    Plastic fragments and particles as an emerging environmental contaminant and pollutant are gaining scientific attention in the recent decades due to the potential threats on biota. This study aims to elucidate the presence, abundance and temporal change of plastic fragments and particles from two selected beaches, namely Santubong and Trombol in Kuching on two sampling times. Morphological and polymer identification assessment on the recovered plastics was also conducted. Overall comparison statistical analysis revealed that the abundance of plastic fragments/debris on both of sampling stations were insignificantly different (p>0.05). Likewise, statistical analysis on the temporal changes on the abundance yielded no significant difference for most of the sampling sites on each respective station, except STB-S2. Morphological studies revealed physical features of plastic fragments and debris were diverse in shapes, sizes, colors and surface fatigues. FTIR fingerprinting analysis shows that polypropylene and polyethylene were the dominant plastic polymers debris on both beaches.

  12. 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

  13. In vitro functional screening as a means to identify new plasticizers devoid of reproductive toxicity

    International Nuclear Information System (INIS)

    Boisvert, Annie; Jones, Steven; Issop, Leeyah; Erythropel, Hanno C.; Papadopoulos, Vassilios; Culty, Martine

    2016-01-01

    Plasticizers are indispensable additives providing flexibility and malleability to plastics. Among them, several phthalates, including di (2-ethylhexyl) phthalate (DEHP), have emerged as endocrine disruptors, leading to their restriction in consumer products and creating a need for new, safer plasticizers. The goal of this project was to use in vitro functional screening tools to select novel non-toxic plasticizers suitable for further in vivo evaluation. A panel of novel compounds with satisfactory plasticizer properties and biodegradability were tested, along with several commercial plasticizers, such as diisononyl-cyclohexane-1,2-dicarboxylate (DINCH®). MEHP, the monoester metabolite of DEHP was also included as reference compound. Because phthalates target mainly testicular function, including androgen production and spermatogenesis, we used the mouse MA-10 Leydig and C18-4 spermatogonial cell lines as surrogates to examine cell survival, proliferation, steroidogenesis and mitochondrial integrity. The most promising compounds were further assessed on organ cultures of rat fetal and neonatal testes, corresponding to sensitive developmental windows. Dose-response studies revealed the toxicity of most maleates and fumarates, while identifying several dibenzoate and succinate plasticizers as innocuous on Leydig and germ cells. Interestingly, DINCH®, a plasticizer marketed as a safe alternative to phthalates, exerted a biphasic effect on steroid production in MA-10 and fetal Leydig cells. MEHP was the only plasticizer inducing the formation of multinucleated germ cells (MNG) in organ culture. Overall, organ cultures corroborated the cell line data, identifying one dibenzoate and one succinate as the most promising candidates. The adoption of such collaborative approaches for developing new chemicals should help prevent the development of compounds potentially harmful to human health. - Highlights: • Phthalate plasticizers exert toxic effects on male reproduction

  14. In vitro functional screening as a means to identify new plasticizers devoid of reproductive toxicity

    Energy Technology Data Exchange (ETDEWEB)

    Boisvert, Annie; Jones, Steven; Issop, Leeyah [The Research Institute of the McGill University Health Centre, McGill University, Montreal, Quebec, Canada H4A 3J1 (Canada); Department of Medicine, McGill University, Montreal, Quebec, Canada H4A 3J1 (Canada); Erythropel, Hanno C. [Department of Chemical Engineering, McGill University, Montreal, Quebec, Canada H4A 3J1 (Canada); Papadopoulos, Vassilios [The Research Institute of the McGill University Health Centre, McGill University, Montreal, Quebec, Canada H4A 3J1 (Canada); Department of Medicine, McGill University, Montreal, Quebec, Canada H4A 3J1 (Canada); Department of Pharmacology & Therapeutics, McGill University, Montreal, Quebec, Canada H4A 3J1 (Canada); Culty, Martine, E-mail: martine.culty@mcgill.ca [The Research Institute of the McGill University Health Centre, McGill University, Montreal, Quebec, Canada H4A 3J1 (Canada); Department of Medicine, McGill University, Montreal, Quebec, Canada H4A 3J1 (Canada); Department of Pharmacology & Therapeutics, McGill University, Montreal, Quebec, Canada H4A 3J1 (Canada)

    2016-10-15

    Plasticizers are indispensable additives providing flexibility and malleability to plastics. Among them, several phthalates, including di (2-ethylhexyl) phthalate (DEHP), have emerged as endocrine disruptors, leading to their restriction in consumer products and creating a need for new, safer plasticizers. The goal of this project was to use in vitro functional screening tools to select novel non-toxic plasticizers suitable for further in vivo evaluation. A panel of novel compounds with satisfactory plasticizer properties and biodegradability were tested, along with several commercial plasticizers, such as diisononyl-cyclohexane-1,2-dicarboxylate (DINCH®). MEHP, the monoester metabolite of DEHP was also included as reference compound. Because phthalates target mainly testicular function, including androgen production and spermatogenesis, we used the mouse MA-10 Leydig and C18-4 spermatogonial cell lines as surrogates to examine cell survival, proliferation, steroidogenesis and mitochondrial integrity. The most promising compounds were further assessed on organ cultures of rat fetal and neonatal testes, corresponding to sensitive developmental windows. Dose-response studies revealed the toxicity of most maleates and fumarates, while identifying several dibenzoate and succinate plasticizers as innocuous on Leydig and germ cells. Interestingly, DINCH®, a plasticizer marketed as a safe alternative to phthalates, exerted a biphasic effect on steroid production in MA-10 and fetal Leydig cells. MEHP was the only plasticizer inducing the formation of multinucleated germ cells (MNG) in organ culture. Overall, organ cultures corroborated the cell line data, identifying one dibenzoate and one succinate as the most promising candidates. The adoption of such collaborative approaches for developing new chemicals should help prevent the development of compounds potentially harmful to human health. - Highlights: • Phthalate plasticizers exert toxic effects on male reproduction

  15. Determining the amount of waste plastics in the feed of Austrian waste-to-energy facilities.

    Science.gov (United States)

    Schwarzböck, Therese; Van Eygen, Emile; Rechberger, Helmut; Fellner, Johann

    2017-02-01

    Although thermal recovery of waste plastics is widely practiced in many European countries, reliable information on the amount of waste plastics in the feed of waste-to-energy plants is rare. In most cases the amount of plastics present in commingled waste, such as municipal solid waste, commercial, or industrial waste, is estimated based on a few waste sorting campaigns, which are of limited significance with regard to the characterisation of plastic flows. In the present study, an alternative approach, the so-called Balance Method, is used to determine the total amount of plastics thermally recovered in Austria's waste incineration facilities in 2014. The results indicate that the plastics content in the waste feed may vary considerably among different plants but also over time. Monthly averages determined range between 8 and 26 wt% of waste plastics. The study reveals an average waste plastics content in the feed of Austria's waste-to-energy plants of 16.5 wt%, which is considerably above findings from sorting campaigns conducted in Austria. In total, about 385 kt of waste plastics were thermally recovered in all Austrian waste-to-energy plants in 2014, which equals to 45 kg plastics cap -1 . In addition, the amount of plastics co-combusted in industrial plants yields a total thermal utilisation rate of 70 kg cap -1  a -1 for Austria. This is significantly above published rates, for example, in Germany reported rates for 2013 are in the range of only 40 kg of waste plastics combusted per capita.

  16. Body dysmorphia and plastic surgery.

    Science.gov (United States)

    Kyle, Allison

    2012-01-01

    Body dysmorphic disorder is a mental disorder characterized by a preoccupation with some aspect of one's appearance. In cosmetic surgery, this preoccupation can be overlooked by practitioners resulting in a discrepancy between expected and realistic outcome. Identifying the characteristics of this disorder may be crucial to the practitioner-patient relationship in the plastic surgery setting.

  17. Ways of Viewing Pictorial Plasticity

    NARCIS (Netherlands)

    Wijntjes, M.W.A.

    2017-01-01

    The plastic effect is historically used to denote various forms of stereopsis. The vivid impression of depth often associated with binocular stereopsis can also be achieved in other ways, for example, using a synopter. Accounts of this go back over a hundred years. These ways of viewing all aim

  18. Ways of Viewing Pictorial Plasticity

    Directory of Open Access Journals (Sweden)

    Maarten W. A. Wijntjes

    2017-03-01

    Full Text Available The plastic effect is historically used to denote various forms of stereopsis. The vivid impression of depth often associated with binocular stereopsis can also be achieved in other ways, for example, using a synopter. Accounts of this go back over a hundred years. These ways of viewing all aim to diminish sensorial evidence that the picture is physically flat. Although various viewing modes have been proposed in the literature, their effects have never been compared. In the current study, we compared three viewing modes: monocular blur, synoptic viewing, and free viewing (using a placebo synopter. By designing a physical embodiment that was indistinguishable for the three experimental conditions, we kept observers naïve with respect to the differences between them; 197 observers participated in an experiment where the three viewing modes were compared by performing a rating task. Results indicate that synoptic viewing causes the largest plastic effect. Monocular blur scores lower than synoptic viewing but is still rated significantly higher than the baseline conditions. The results strengthen the idea that synoptic viewing is not due to a placebo effect. Furthermore, monocular blur has been verified for the first time as a way of experiencing the plastic effect, although the effect is smaller than synoptic viewing. We discuss the results with respect to the theoretical basis for the plastic effect. We show that current theories are not described with sufficient details to explain the differences we found.

  19. Ways of Viewing Pictorial Plasticity.

    Science.gov (United States)

    Wijntjes, Maarten W A

    2017-01-01

    The plastic effect is historically used to denote various forms of stereopsis. The vivid impression of depth often associated with binocular stereopsis can also be achieved in other ways, for example, using a synopter. Accounts of this go back over a hundred years. These ways of viewing all aim to diminish sensorial evidence that the picture is physically flat. Although various viewing modes have been proposed in the literature, their effects have never been compared. In the current study, we compared three viewing modes: monocular blur, synoptic viewing, and free viewing (using a placebo synopter). By designing a physical embodiment that was indistinguishable for the three experimental conditions, we kept observers naïve with respect to the differences between them; 197 observers participated in an experiment where the three viewing modes were compared by performing a rating task. Results indicate that synoptic viewing causes the largest plastic effect. Monocular blur scores lower than synoptic viewing but is still rated significantly higher than the baseline conditions. The results strengthen the idea that synoptic viewing is not due to a placebo effect. Furthermore, monocular blur has been verified for the first time as a way of experiencing the plastic effect, although the effect is smaller than synoptic viewing. We discuss the results with respect to the theoretical basis for the plastic effect. We show that current theories are not described with sufficient details to explain the differences we found.

  20. Electron beam micromachining of plastics

    Czech Academy of Sciences Publication Activity Database

    Dupák, Libor

    2014-01-01

    Roč. 49, 5-6 (2014), s. 310-314 ISSN 0861-4717 R&D Projects: GA MŠk(CZ) LO1212; GA MŠk ED0017/01/01; GA MŠk EE.2.3.20.0103 Institutional support: RVO:68081731 Keywords : micromachining of plastics * Electron beam Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering

  1. Field based plastic contamination sensing

    Science.gov (United States)

    The United States has a long-held reputation of being a dependable source of high quality, contaminant-free cotton. Recently, increased incidence of plastic contamination from sources such as shopping bags, vegetable mulch, surface irrigation tubing, and module covers has threatened the reputation o...

  2. Recycling of plastics in Germany

    International Nuclear Information System (INIS)

    Thienen, N. von; Patel, M.

    1999-01-01

    This article deals with the waste management of post-consumer plastics in Germany and its potential to save fossil fuels and reduce CO 2 emissions. Since most experience is available for packaging, the paper first gives an overview of the legislative background and the material flows for this sector. Then recycling and recovery processes for plastics waste from all sectors are assessed in terms of their contribution to energy saving and CO 2 abatement. Practically all the options studied show a better performance than waste treatment in an average incinerator which has been chosen as the reference case. High ecological benefits can be achieved by mechanical recycling if virgin polymers are substituted. The paper then presents different scenarios for managing plastic waste in Germany in 1995: considerable savings can be made by strongly enhancing the efficiency of waste incinerators. Under these conditions the distribution of plastics waste among mechanical recycling, feedstock recycling and energy recovery has a comparatively mall impact on the overall results. The maximum savings amount to 74 PJ of energy, i.e, 9% of the chemical sector energy demand in 1995 and 7.0 Mt CO 2 , representing 13% of the sector's emissions. The assessment does not support a general recommendation of energy recovery due to the large difference between the German average and the best available municipal waste-to-energy facilities and also due to new technological developments in the field of mechanical recycling

  3. 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

  4. 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

  5. Toward Modeling Limited Plasticity in Ceramic Materials

    National Research Council Canada - National Science Library

    Grinfeld, Michael; Schoenfeld, Scott E; Wright, Tim W

    2008-01-01

    The characteristic features of many armor-related ceramic materials are the anisotropy on the micro-scale level and the very limited, though non-vanishing, plasticity due to limited number of the planes for plastic slip...

  6. Antireflection coatings on plastics deposited by plasma ...

    Indian Academy of Sciences (India)

    In the ophthalmic industry, plastic lenses are rapidly displacing glass lenses ... Moreover, the plasma polymerization process allows deposition of optical films at room temperature, essential for plastics. ... Bulletin of Materials Science | News.

  7. Mechanical behaviour of nanoparticles: Elasticity and plastic ...

    Indian Academy of Sciences (India)

    2015-06-03

    Jun 3, 2015 ... Mechanical behaviour of nanoparticles: Elasticity and plastic deformation mechanisms ... The main results in terms of elasticity and plastic deformation mechanisms are then reported ... Pramana – Journal of Physics | News.

  8. Recycling plastic bottles in a creative way

    OpenAIRE

    Pavlin, Suzana

    2016-01-01

    Beside other plastic products, plastic bottles represent a true environmental disaster in the last few years. We assume that hardly anyone asks what happens after they drink that last drop of water out of it. Just like most municipal waste, a plastic bottle can be reused, recycled, burned or deposited into landfill. When the Environment Protection Act is not respected, plastic bottle ends up in the nature, very often in the sea, where it decomposes very slowly and has negative influence on th...

  9. Plastic Accumulation in the Mediterranean Sea

    OpenAIRE

    C?zar, Andr?s; Sanz-Mart?n, Marina; Mart?, Elisa; Gonz?lez-Gordillo, J. Ignacio; Ubeda, B?rbara; G?lvez, Jos? ?.; Irigoien, Xabier; Duarte, Carlos M.

    2015-01-01

    Copyright: © 2015 Cózar et al. Concentrations of floating plastic were measured throughout the Mediterranean Sea to assess whether this basin can be regarded as a great accumulation region of plastic debris. We found that the average density of plastic (1 item per 4 m2), as well as its frequency of occurrence (100% of the sites sampled), are comparable to the accumulation zones described for the five subtropical ocean gyres. Plastic debris in the Mediterranean surface waters was dominated by ...

  10. ARE PLASTIC GROCERY BAGS SACKING THE ENVIRONMENT?

    Directory of Open Access Journals (Sweden)

    Mangal Gogte

    2009-12-01

    Full Text Available This paper is oriented on analysis impacts of plastic bags on environment. In this paper is analyzed did plastic bags are so harmful, and what are the main ingredients of it. One part of this paper is oriented on effects of plastic bags and management of their usage. There is also made comparative analysis between impacts of plastic and paper bags on environment.

  11. PLASTIC ANALYSIS OF STEEL FRAME STRUCTURE

    Directory of Open Access Journals (Sweden)

    M. Rogac

    2013-05-01

    Full Text Available This paper presents the plastic analysis of steel frame structure loaded by gravity loads. By applying the cinematic theorem of ultimate analysis, the ultimate load for the case of elastic - ideally plastic material is calculated. The identical structure was treated in the computer program SAP2000 where the zone of material reinforcement in the plastic area was covered. Keywords: Steel frame structure, plastic analysis, ultimate gravity load, material reinforcement.

  12. Functional nanostructures on injection molded plastic

    DEFF Research Database (Denmark)

    Johansson, Alicia Charlotte; Søgaard, Emil; Andersen, Nis Korsgaard

    Nanotechnology can be used to make inexpensive plastic parts with functional surfaces. The plastic parts can be molded using a standard injection molding process. The nanostructures are directly transferred from the surface of the molding tool to the surface of the molded plastic part during...

  13. 7 CFR 58.326 - Plastic cream.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 3 2010-01-01 2010-01-01 false Plastic cream. 58.326 Section 58.326 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Standards... Material § 58.326 Plastic cream. To produce plastic cream eligible for official certification, the quality...

  14. Use of Plastic Mulch for Vegetable Production

    OpenAIRE

    Maughan, Tiffany; Drost, Dan

    2016-01-01

    Plastic mulches are used commercially for both vegetables and small fruit crops. Vegetable crops well suited for production with plastic mulch are typically high value row crops. This fact sheet describes the advantages, disadvantages, installation, and planting considerations. It includes sources for plastic and equipment.

  15. The evolution of age-dependent plasticity

    NARCIS (Netherlands)

    Fischer, Barbara; van Doorn, G. Sander; Dieckmann, Ulf; Taborsky, Barbara

    2014-01-01

    When organisms encounter environments that are heterogeneous in time, phenotypic plasticity is often favored by selection. The degree of such plasticity can vary during an organism''s lifetime, but the factors promoting differential plastic responses at different ages or life stages remain poorly

  16. Plastic Debris Is a Human Health Issue

    NARCIS (Netherlands)

    Vethaak, A.D.; Leslie, H.A.

    2016-01-01

    The global threat of highly persistent plastic waste accumulating and fragmenting in the world’s oceans, inland waters and terrestrial environments is becoming increasingly evident.1−3 Humans are being exposed to both plastic particles and chemical additives being released from the plastic debris of

  17. Social media use and impact on plastic surgery practice.

    Science.gov (United States)

    Vardanian, Andrew J; Kusnezov, Nicholas; Im, Daniel D; Lee, James C; Jarrahy, Reza

    2013-05-01

    Social media platforms have revolutionized the way human beings communicate, yet there is little evidence describing how the plastic surgery community has adopted social media. In this article, the authors evaluate current trends in social media use by practicing plastic surgeons. An anonymous survey on the use of social media was distributed to members of the American Society of Plastic Surgeons. Prevalent patterns of social media implementation were elucidated. One-half of respondents were regular social media users. Reasons for using social media included the beliefs that incorporation of social media into medical practice is inevitable (56.7 percent), that they are an effective marketing tool (52.1 percent), and that they provide a forum for patient education (49 percent). Surgeons with a primarily aesthetic surgery practice were more likely to use social media. Most respondents (64.6 percent) stated that social media had no effect on their practice, whereas 33.8 percent reported a positive impact and 1.5 percent reported a negative impact. This study depicts current patterns of social media use by plastic surgeons, including motivations driving its implementation and impressions on its impact. Many feel that social media are an effective marketing tool that generates increased exposure and referrals. A small number of surgeons have experienced negative repercussions from social media involvement. Our study reveals the presence of a void. There is a definite interest among those surveyed in developing best practice standards and oversight to ensure ethical use of social media platforms throughout the plastic surgery community. Continuing discussion regarding these matters should be ongoing as our experience with social media in plastic surgery evolves.

  18. 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

  19. 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...

  20. Technical specifications for mechanical recycling of agricultural plastic waste

    International Nuclear Information System (INIS)

    Briassoulis, D.; Hiskakis, M.; Babou, E.

    2013-01-01

    Highlights: • Technical specifications for agricultural plastic wastes (APWs) recycling proposed. • Specifications are the base for best economical and environmental APW valorisation. • Analysis of APW reveals inherent characteristics and constraints of APW streams. • Thorough survey on mechanical recycling processes and industry as it applies to APW. • Specifications for APW recycling tested, adjusted and verified through pilot trials. - Abstract: Technical specifications appropriate for the recycling of agricultural plastic wastes (APWs), widely accepted by the recycling industry were developed. The specifications establish quality standards to be met by the agricultural plastics producers, users and the agricultural plastic waste management chain. They constitute the base for the best economical and environmental valorisation of the APW. The analysis of the APW streams conducted across Europe in the framework of the European project “LabelAgriWaste” revealed the inherent characteristics of the APW streams and the inherent constraints (technical or economical) of the APW. The APW stream properties related to its recycling potential and measured during pilot trials are presented and a subsequent universally accepted simplified and expanded list of APW recycling technical specifications is proposed and justified. The list includes two sets of specifications, applied to two different quality categories of recyclable APW: one for pellet production process (“Quality I”) and another one for plastic profile production process (“Quality II”). Parameters that are taken into consideration in the specifications include the APW physical characteristics, contamination, composition and degradation. The proposed specifications are focused on polyethylene based APW that represents the vast majority of the APW stream. However, the specifications can be adjusted to cover also APW of different materials (e.g. PP or PVC) that are found in very small quantities

  1. 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...

  2. Plasticity Approach to Shear Design

    DEFF Research Database (Denmark)

    Hoang, Cao Linh; Nielsen, Mogens Peter

    1998-01-01

    The paper presents some plastic models for shear design of reinforced concrete beams. Distinction is made between two shear failure modes, namely web crushing and crack sliding. The first mentioned mode is met in beams with large shear reinforcement degrees. The mode of crack sliding is met in non......-shear reinforced beams as well as in lightly shear reinforced beams. For such beams the shear strength is determined by the recently developed crack sliding model. This model is based upon the hypothesis that cracks can be transformed into yield lines, which have lower sliding resistance than yield lines formed...... in uncracked concrete. Good agree between theory and tests has been found.Keywords: dsign, plasticity, reinforced concrete, reinforcement, shear, web crushing....

  3. Computational Strain Gradient Crystal Plasticity

    DEFF Research Database (Denmark)

    Niordson, Christian Frithiof; Kysar, Jeffrey W.

    2011-01-01

    A model for strain gradient crystal visco-plasticity is formulated along the lines proposed by Fleck andWillis (2009) for isotropic plasticity. Size-effects are included in the model due to the addition of gradient terms in both the free energy as well as through a dissipation potential. A finite...... element solution method is presented, which delivers the slip-rate field and the velocity-field based on two minimum principles. Some plane deformation problems relevant for certain specific orientations of a face centered cubic crystal under plane loading conditions are studied, and effective in......-plane parameters are developed based on the crystallographic properties of the material. The problem of cyclic shear of a single crystal between rigid platens is studied as well as void growth of a cylindrical void....

  4. Alternative Diesel from Waste Plastics

    Directory of Open Access Journals (Sweden)

    Stella Bezergianni

    2017-10-01

    Full Text Available The long term ambition of energy security and solidarity, coupled with the environmental concerns of problematic waste accumulation, is addressed via the proposed waste-to-fuel technology. Plastic waste is converted into automotive diesel fuel via a two-step thermochemical process based on pyrolysis and hydrotreatment. Plastic waste was pyrolyzed in a South East Asia plant rendering pyrolysis oil, which mostly consisted of middle-distillate (naphtha and diesel hydrocarbons. The diesel fraction (170–370 °C was fractionated, and its further upgrade was assessed in a hydroprocessing pilot plant at the Centre for Research and Technology Hellas (CERTH in Greece. The final fuel was evaluated with respect to the diesel fuel quality specifications EN 590, which characterized it as a promising alternative diesel pool component with excellent ignition quality characteristics and low back end volatility.

  5. Polishing compound for plastic surfaces

    Science.gov (United States)

    Stowell, M.S.

    1991-01-01

    This invention is comprised of a polishing compound for plastic materials. The compound includes approximately by approximately by weight 25 to 80 parts at least one petroleum distillate lubricant, 1 to 12 parts mineral spirits, 50 to 155 parts abrasive paste, and 15 to 60 parts water. Preferably, the compound includes approximately 37 to 42 parts at least one petroleum distillate lubricant, up to 8 parts mineral spirits, 95 to 110 parts abrasive paste, and 50 to 55 parts water. The proportions of the ingredients are varied in accordance with the particular application. The compound is used on PLEXIGLAS{trademark}, LEXAN{trademark}, LUCITE{trademark}, polyvinyl chloride (PVC), and similar plastic materials whenever a smooth, clear polished surface is desired.

  6. Temperature dependence of plastic scintillators

    Science.gov (United States)

    Peralta, L.

    2018-03-01

    Plastic scintillator detectors have been studied as dosimeters, since they provide a cost-effective alternative to conventional ionization chambers. Several articles have reported undesired response dependencies on beam energy and temperature, which provides the motivation to determine appropriate correction factors. In this work, we studied the light yield temperature dependency of four plastic scintillators, BCF-10, BCF-60, BC-404, RP-200A and two clear fibers, BCF-98 and SK-80. Measurements were made using a 50 kVp X-ray beam to produce the scintillation and/or radioluminescence signal. The 0 to 40 °C temperature range was scanned for each scintillator, and temperature coefficients were obtained.

  7. Vascular plasticity in cerebrovascular disorders

    DEFF Research Database (Denmark)

    Edvinsson, Lars I H; Povlsen, Gro Klitgaard

    2011-01-01

    Cerebral ischemia remains a major cause of morbidity and mortality with little advancement in subacute treatment options. This review aims to cover and discuss novel insight obtained during the last decade into plastic changes in the vasoconstrictor receptor profiles of cerebral arteries and micr......Cerebral ischemia remains a major cause of morbidity and mortality with little advancement in subacute treatment options. This review aims to cover and discuss novel insight obtained during the last decade into plastic changes in the vasoconstrictor receptor profiles of cerebral arteries...... therapeutic target for prevention of vasoconstrictor receptor upregulation after stroke. Together, those findings provide new perspectives on the pathophysiology of ischemic stroke and point toward a novel way of reducing vasoconstriction, neuronal cell death, and thus neurologic deficits after stroke....

  8. Process for remediation of plastic waste

    Science.gov (United States)

    Pol, Vilas G [Westmont, IL; Thiyagarajan, Pappannan [Germantown, MD

    2012-04-10

    A single step process for degrading plastic waste by converting the plastic waste into carbonaceous products via thermal decomposition of the plastic waste by placing the plastic waste into a reactor, heating the plastic waste under an inert or air atmosphere until the temperature of 700.degree. C. is achieved, allowing the reactor to cool down, and recovering the resulting decomposition products therefrom. The decomposition products that this process yields are carbonaceous materials, and more specifically egg-shaped and spherical-shaped solid carbons. Additionally, in the presence of a transition metal compound, this thermal decomposition process produces multi-walled carbon nanotubes.

  9. Learning and plasticity in adolescence

    OpenAIRE

    Fuhrmann, Delia Ute Dorothea

    2017-01-01

    Adolescence is the period of life between puberty and relative independence. It is a time during which the human brain undergoes protracted changes - particularly in the frontal, parietal and temporal cortices. These changes have been linked to improvements in cognitive performance; and are thought to render adolescence a period of relatively high levels of plasticity, during which the environment has a heightened impact on brain development and behaviour. This thesis investigates learning an...

  10. Studies of novel plastic scintillators

    International Nuclear Information System (INIS)

    McInally, I.D.

    1979-08-01

    The general aim of this study was to synthesize fluorescent compounds which are capable of polymerisation, to prepare polymers and co-polymers from these compounds and to study the photophysical properties of these materials. In this way it is hoped to produce plastic scintillators exhibiting improved energy transfer efficiency. Materials studied included POS(2-phenyl-5-(p vinyl) phenyloxazole) vinyl naphthalene, methyl anthracene terminated poly vinyl toluene) and derivatives of BuPBD. (author)

  11. Ways of Viewing Pictorial Plasticity

    OpenAIRE

    Maarten W. A. Wijntjes

    2017-01-01

    The plastic effect is historically used to denote various forms of stereopsis. The vivid impression of depth often associated with binocular stereopsis can also be achieved in other ways, for example, using a synopter. Accounts of this go back over a hundred years. These ways of viewing all aim to diminish sensorial evidence that the picture is physically flat. Although various viewing modes have been proposed in the literature, their effects have never been compared. In the current study, we...

  12. 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.

  13. Dosage-dependent non-linear effect of L-dopa on human motor cortex plasticity.

    Science.gov (United States)

    Monte-Silva, Katia; Liebetanz, David; Grundey, Jessica; Paulus, Walter; Nitsche, Michael A

    2010-09-15

    The neuromodulator dopamine affects learning and memory formation and their likely physiological correlates, long-term depression and potentiation, in animals and humans. It is known from animal experiments that dopamine exerts a dosage-dependent, inverted U-shaped effect on these functions. However, this has not been explored in humans so far. In order to reveal a non-linear dose-dependent effect of dopamine on cortical plasticity in humans, we explored the impact of 25, 100 and 200 mg of L-dopa on transcranial direct current (tDCS)-induced plasticity in twelve healthy human subjects. The primary motor cortex served as a model system, and plasticity was monitored by motor evoked potential amplitudes elicited by transcranial magnetic stimulation. As compared to placebo medication, low and high dosages of L-dopa abolished facilitatory as well as inhibitory plasticity, whereas the medium dosage prolonged inhibitory plasticity, and turned facilitatory plasticity into inhibition. Thus the results show clear non-linear, dosage-dependent effects of dopamine on both facilitatory and inhibitory plasticity, and support the assumption of the importance of a specific dosage of dopamine optimally suited to improve plasticity. This might be important for the therapeutic application of dopaminergic agents, especially for rehabilitative purposes, and explain some opposing results in former studies.

  14. Vocal plasticity in a reptile.

    Science.gov (United States)

    Brumm, Henrik; Zollinger, Sue Anne

    2017-05-31

    Sophisticated vocal communication systems of birds and mammals, including human speech, are characterized by a high degree of plasticity in which signals are individually adjusted in response to changes in the environment. Here, we present, to our knowledge, the first evidence for vocal plasticity in a reptile. Like birds and mammals, tokay geckos ( Gekko gecko ) increased the duration of brief call notes in the presence of broadcast noise compared to quiet conditions, a behaviour that facilitates signal detection by receivers. By contrast, they did not adjust the amplitudes of their call syllables in noise (the Lombard effect), which is in line with the hypothesis that the Lombard effect has evolved independently in birds and mammals. However, the geckos used a different strategy to increase signal-to-noise ratios: instead of increasing the amplitude of a given call type when exposed to noise, the subjects produced more high-amplitude syllable types from their repertoire. Our findings demonstrate that reptile vocalizations are much more flexible than previously thought, including elaborate vocal plasticity that is also important for the complex signalling systems of birds and mammals. We suggest that signal detection constraints are one of the major forces driving the evolution of animal communication systems across different taxa. © 2017 The Author(s).

  15. Plastic buckling of cylindrical shells

    International Nuclear Information System (INIS)

    Bandyopadhyay, K.; Xu, J.; Shteyngart, S.; Eckert, H.

    1994-01-01

    Cylindrical shells exhibit buckling under axial loads at stresses much less than the respective theoretical critical stresses. This is due primarily to the presence of geometrical imperfections even though such imperfections could be very small (e.g., comparable to thickness). Under internal pressure, the shell regains some of its buckling strength. For a relatively large radius-to-thickness ratio and low internal pressure, the effect can be reasonably estimated by an elastic analysis. However, for low radius-to-thickness ratios and greater pressures, the elastic-plastic collapse controls the failure load. in order to quantify the elastic-plastic buckling capacity of cylindrical shells, an analysis program was carried out by use of the computer code BOSOR5 developed by Bushnell of Lockheed Missiles and Space Company. The analysis was performed for various radius-to-thickness ratios and imperfection amplitudes. The purpose of the analytical program was to compute the buckling strength of underground cylindrical tanks, that are used for storage of nuclear wastes, for realistic geometric imperfections and internal pressure loads. This paper presents the results of the elastic-plastic analyses and compares them with other available information for various pressure loads

  16. 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

  17. Communicative conduct in commercial medicine: initial consultations between plastic surgeons and prospective clients.

    Science.gov (United States)

    Mirivel, Julien C

    2010-06-01

    In this study, I investigated naturally occurring medical interaction in commercial medicine. Drawing on 30+ hours of videotaped data and 9 months of fieldwork in a cosmetic surgery clinic, this analysis focuses on how plastic surgeons interact with patients who seek to alter their bodily appearance. The ethnographically informed discourse analysis reveals how plastic surgeons manage multiple and competing interactive demands. Specifically, I describe plastic surgeons' key strategies for meeting both health-related and institutional goals. In the conclusion, I reflect on the communication challenges that medical professionals and patients face when consumerism and medicine meet.

  18. The application of endochronic plasticity theory in modeling the dynamic inelastic response of structural systems

    International Nuclear Information System (INIS)

    Lin, H.C.; Hsieh, B.J.; Valentin, R.A.

    1981-01-01

    The endochronic theory of plasticity proposed by Valanis has been applied in predicting the inelastic responses of structural systems. A recently developed convected coordinates finite-element program has been modified to use an endochronic constitutive law. A series of sample problems for a variety of dynamic loadings are presented. The calculations that have been performed comparing classical and endochronic plasticity theories have revealed that the endochronic approach can result in a substantial reduction in computer time for equivalent solution accuracy. This result, combined with the apparent accuracy of material representation indicate that the use of endochronic plasticity has great potential in evaluating the dynamic response of structural systems. (orig.)

  19. Plasticity of ductile metallic glasses: a self-organized critical state.

    Science.gov (United States)

    Sun, B A; Yu, H B; Jiao, W; Bai, H Y; Zhao, D Q; Wang, W H

    2010-07-16

    We report a close correlation between the dynamic behavior of serrated flow and the plasticity in metallic glasses (MGs) and show that the plastic deformation of ductile MGs can evolve into a self-organized critical state characterized by the power-law distribution of shear avalanches. A stick-slip model considering the interaction of multiple shear bands is presented to reveal complex scale-free intermittent shear-band motions in ductile MGs and quantitatively reproduce the experimental observations. Our studies have implications for understanding the precise plastic deformation mechanism of MGs.

  20. 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.

  1. Processing and characterization of 3D dense chitosan pieces, for orthopedic applications, by adding plasticizers

    OpenAIRE

    Figueiredo, Lígia; Moura, Carla; Pinto, Luís F. V.; Ferreira, Frederico Castelo; Rodrigues, Alexandra

    2015-01-01

    In this work, plasticizer agents were incorporated in a chitosan based formulation, as a strategy to improve the fragile structure of chitosan based-materials. Three different plasticizers: ethylene glycol, glycerol and sorbitol, were blended with chitosan to prepare 3D dense chitosan specimens. The properties of the obtained structures were assessed for mechanical, microstructural, physical and biocompatibility behavior. The results obtained revealed that from the different specimens prepare...

  2. Plasticity of peripheral auditory frequency sensitivity in Emei music frog.

    Science.gov (United States)

    Zhang, Dian; Cui, Jianguo; Tang, Yezhong

    2012-01-01

    In anurans reproductive behavior is strongly seasonal. During the spring, frogs emerge from hibernation and males vocalize for mating or advertising territories. Female frogs have the ability to evaluate the quality of the males' resources on the basis of these vocalizations. Although studies revealed that central single torus semicircularis neurons in frogs exhibit season plasticity, the plasticity of peripheral auditory sensitivity in frog is unknown. In this study the seasonally plasticity of peripheral auditory sensitivity was test in the Emei music frog Babina daunchina, by comparing thresholds and latencies of auditory brainstem responses (ABRs) evoked by tone pips and clicks in the reproductive and non-reproductive seasons. The results show that both ABR thresholds and latency differ significantly between the reproductive and non-reproductive seasons. The thresholds of tone pip evoked ABRs in the non-reproductive season increased significantly about 10 dB than those in the reproductive season for frequencies from 1 KHz to 6 KHz. ABR latencies to waveform valley values for tone pips for the same frequencies using appropriate threshold stimulus levels are longer than those in the reproductive season for frequencies from 1.5 to 6 KHz range, although from 0.2 to 1.5 KHz range it is shorter in the non-reproductive season. These results demonstrated that peripheral auditory frequency sensitivity exhibits seasonal plasticity changes which may be adaptive to seasonal reproductive behavior in frogs.

  3. Plasticity of peripheral auditory frequency sensitivity in Emei music frog.

    Directory of Open Access Journals (Sweden)

    Dian Zhang

    Full Text Available In anurans reproductive behavior is strongly seasonal. During the spring, frogs emerge from hibernation and males vocalize for mating or advertising territories. Female frogs have the ability to evaluate the quality of the males' resources on the basis of these vocalizations. Although studies revealed that central single torus semicircularis neurons in frogs exhibit season plasticity, the plasticity of peripheral auditory sensitivity in frog is unknown. In this study the seasonally plasticity of peripheral auditory sensitivity was test in the Emei music frog Babina daunchina, by comparing thresholds and latencies of auditory brainstem responses (ABRs evoked by tone pips and clicks in the reproductive and non-reproductive seasons. The results show that both ABR thresholds and latency differ significantly between the reproductive and non-reproductive seasons. The thresholds of tone pip evoked ABRs in the non-reproductive season increased significantly about 10 dB than those in the reproductive season for frequencies from 1 KHz to 6 KHz. ABR latencies to waveform valley values for tone pips for the same frequencies using appropriate threshold stimulus levels are longer than those in the reproductive season for frequencies from 1.5 to 6 KHz range, although from 0.2 to 1.5 KHz range it is shorter in the non-reproductive season. These results demonstrated that peripheral auditory frequency sensitivity exhibits seasonal plasticity changes which may be adaptive to seasonal reproductive behavior in frogs.

  4. Hydrogen-Induced Plastic Deformation in ZnO

    Science.gov (United States)

    Lukáč, F.; Čížek, J.; Vlček, M.; Procházka, I.; Anwand, W.; Brauer, G.; Traeger, F.; Rogalla, D.; Becker, H.-W.

    In the present work hydrothermally grown ZnO single crystals covered with Pd over-layer were electrochemically loaded with hydrogen and the influence of hydrogen on ZnO micro structure was investigated by positron annihilation spectroscopy (PAS). Nuclear reaction analysis (NRA) was employed for determination of depth profile of hydrogen concentration in the sample. NRA measurements confirmed that a substantial amount of hydrogen was introduced into ZnO by electrochemical charging. The bulk hydrogen concentration in ZnO determined by NRA agrees well with the concentration estimated from the transported charge using the Faraday's law. Moreover, a subsurface region with enhanced hydrogen concentration was found in the loaded crystals. Slow positron implantation spectroscopy (SPIS) investigations of hydrogen-loaded crystal revealed enhanced concentration of defects in the subsurface region. This testifies hydrogen-induced plastic deformation of the loaded crystal. Absorbed hydrogen causes a significant lattice expansion. At low hydrogen concentrations this expansion is accommodated by elastic straining, but at higher concentrations hydrogen-induced stress exceeds the yield stress in ZnO and plastic deformation of the loaded crystal takes place. Enhanced hydrogen concentration detected in the subsurface region by NRA is, therefore, due to excess hydrogen trapped at open volume defects introduced by plastic deformation. Moreover, it was found that hydrogen-induced plastic deformation in the subsurface layer leads to typical surface modification: formation of hexagonal shape pyramids on the surface due to hydrogen-induced slip in the [0001] direction.

  5. Is the holy grail plastic? Radiation identification from plastic scintillators

    International Nuclear Information System (INIS)

    Butchins, L. J. C.; Gosling, J. M.; Hogbin, M. R. W.; Jones, D. C.; Lacey, R. J.; Stearn, J. G.

    2009-01-01

    Thousands of shipping containers containing Naturally Occurring Radioactive Materials (NORM) made from ceramics, stoneware and other natural products are transported worldwide on a daily basis. Some of these NORM loads are sufficiently radioactive to trigger alarms from plastic scintillator detectors which have limited ability to also identify the radionuclides present thus necessitating secondary inspection which increases the operational overhead. Previous studies have been carried out to ascertain if radionuclide discrimination using plastic scintillators is possible with a variety of approaches including deconvolution and computer learning. In this paper, a two stage algorithm is described. An example implementation of the algorithm is presented, applied to operational data, and has been installed in real time operation on a polyvinyl-toluene (PVT) detector. The approach requires the collection of a large library of spectra using examples of the detectors to be deployed. In this study, data from both actual freight loads passing through a port and predefined freight containing various radionuclides were collected. The library represents freight loads that may contain industrial, medical, nuclear, and NORM radionuclides. The radionuclides in the predefined freight were placed in various orientations and in various amounts of shielding to mimic many different scenarios. Preliminary results on an initial subset of data containing industrial and NORM sources show the number of mis-classifications to be less than 1% of the total test data. Good initial results were obtained even for low energy radionuclides such as 241 Am. Where discrimination is not possible, and principle components overlap, this region or 'cloud' of the n-dimensional plot can be put aside. Those spectra that fall in the 'cloud' can be regarded as suspect and in these cases, some secondary screening will still be necessary. It is predicted that the algorithm will enable recognition of NORM loads

  6. 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.

  7. 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...

  8. 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.

  9. "Oriental anthropometry" in plastic surgery

    Directory of Open Access Journals (Sweden)

    Senna-Fernandes Vasco

    2008-01-01

    Full Text Available Background : According to Chinese medicine, the acupuncture-points′ (acupoints locations are proportionally and symmetrically distributed in well-defined compartment zones on the human body surface Oriental Anthropometry" (OA. Acupoints, if considered as aesthetic-loci, might be useful as reference guides in plastic surgery (PS. Aim: This study aimed to use aesthetic-loci as anatomical reference in surgical marking of Aesthetic Plastic Surgery. Method: This was an observational study based on aesthetic surgeries performed in private clinic. This study was based on 106 cases, comprising of 102 women and 4 men, with ages varying from 07 to 73 years, and with heights of between 1.34 m and 1.80 m. Patients were submitted to aesthetic surgical planning by relating aesthetic-loci to conventional surgical marking, including breast surgeries, abdominoplasty, rhytidoplasty, blepharoplasty, and hair implant. The aesthetic-surgical-outcome (ASO of the patients was assessed by a team of plastic surgeons (who were not involved in the surgical procedures over a follow-up period of one year by using a numeric-rating-scale in percentage (% terms. A four-point-verbal-rating-scale was used to record the patients′ opinion of therapeutic-satisfaction (TS. Results: ASO was 75.3 ± 9.4% and TS indicated that most patients (58.5% obtained "good" results. Of the remainder, 38.7% found the results "excellent", and 2.8% found them "fair". Discussion and Conclusion : The data suggested that the use of aesthetic-loci may be a useful tool for PS as an anatomical reference for surgical marking. However, further investigation is required to assess the efficacy of the OA by providing the patients more reliable balance and harmony in facial and body contours surgeries.

  10. Dislocation Dynamics During Plastic Deformation

    CERN Document Server

    Messerschmidt, Ulrich

    2010-01-01

    The book gives an overview of the dynamic behavior of dislocations and its relation to plastic deformation. It introduces the general properties of dislocations and treats the dislocation dynamics in some detail. Finally, examples are described of the processes in different classes of materials, i.e. semiconductors, ceramics, metals, intermetallic materials, and quasicrystals. The processes are illustrated by many electron micrographs of dislocations under stress and by video clips taken during in situ straining experiments in a high-voltage electron microscope showing moving dislocations. Thus, the users of the book also obtain an immediate impression and understanding of dislocation dynamics.

  11. A miniaturized plastic dilution refrigerator

    International Nuclear Information System (INIS)

    Bindilatti, V.; Oliveira, N.F.Jr.; Martin, R.V.; Frossati, G.

    1996-01-01

    We have built and tested a miniaturized dilution refrigerator, completely contained (still, heat exchanger and mixing chamber) inside a plastic (PVC) tube of 10 mm diameter and 170 mm length. With a 25 cm 2 CuNi heat exchanger, it reached temperatures below 50 mK, for circulation rates below 70 μmol/s. The cooling power at 100 mK and 63 μmol/s was 45 μW. The experimental space could accommodate samples up to 6 mm in diameter. (author)

  12. Accelerated Aging Test for Plastic Scintillator Gamma Ray Detectors

    Energy Technology Data Exchange (ETDEWEB)

    Kouzes, Richard T. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2017-05-12

    Polyvinyl toluene (PVT) and polystyrene (PS), collectively referred to as “plastic scintillator,” are synthetic polymer materials used to detect gamma radiation, and are commonly used in instrumentation. Recent studies have revealed that plastic scintillator undergoes an environmentally related material degradation that adversely affects performance under certain conditions and histories. A significant decrease in gamma ray sensitivity has been seen in some detectors in systems as they age. The degradation of sensitivity of plastic scintillator over time is due to a variety of factors, and the term “aging” is used to encompass all factors. Some plastic scintillator samples show no aging effects (no significant change in sensitivity over more than 10 years), while others show severe aging (significant change in sensitivity in less than 5 years). Aging effects arise from weather (variations in heat and humidity), chemical exposure, mechanical stress, light exposure, and loss of volatile components. The damage produced by these various causes can be cumulative, causing observable damage to increase over time. Damage may be reversible up to some point, but becomes permanent under some conditions. It has been demonstrated that exposure of plastic scintillator in an environmental chamber to 30 days of high temperature and humidity (90% relative humidity and 55°C) followed by a single cycle to cold temperature (-30°C) will produce severe fogging in all PVT samples. This thermal cycle will be referred to as the “Accelerated Aging Test.” This document describes the procedure for performing this Accelerated Aging Test.

  13. Biofilm and Diatom Succession on Polyethylene (PE) and Biodegradable Plastic Bags in Two Marine Habitats: Early Signs of Degradation in the Pelagic and Benthic Zone?

    Science.gov (United States)

    Eich, Andreas; Mildenberger, Tobias; Laforsch, Christian; Weber, Miriam

    2015-01-01

    The production of biodegradable plastic is increasing. Given the augmented littering of these products an increasing input into the sea is expected. Previous laboratory experiments have shown that degradation of plastic starts within days to weeks. Little is known about the early composition and activity of biofilms found on biodegradable and conventional plastic debris and its correlation to degradation in the marine environment. In this study we investigated the early formation of biofilms on plastic shopper bags and its consequences for the degradation of plastic. Samples of polyethylene and biodegradable plastic were tested in the Mediterranean Sea for 15 and 33 days. The samples were distributed equally to a shallow benthic (sedimentary seafloor at 6 m water depth) and a pelagic habitat (3 m water depth) to compare the impact of these different environments on fouling and degradation. The amount of biofilm increased on both plastic types and in both habitats. The diatom abundance and diversity differed significantly between the habitats and the plastic types. Diatoms were more abundant on samples from the pelagic zone. We anticipate that specific surface properties of the polymer types induced different biofilm communities on both plastic types. Additionally, different environmental conditions between the benthic and pelagic experimental site such as light intensity and shear forces may have influenced unequal colonisation between these habitats. The oxygen production rate was negative for all samples, indicating that the initial biofilm on marine plastic litter consumes oxygen, regardless of the plastic type or if exposed in the pelagic or the benthic zone. Mechanical tests did not reveal degradation within one month of exposure. However, scanning electron microscopy (SEM) analysis displayed potential signs of degradation on the plastic surface, which differed between both plastic types. This study indicates that the early biofilm formation and composition

  14. Biofilm and Diatom Succession on Polyethylene (PE and Biodegradable Plastic Bags in Two Marine Habitats: Early Signs of Degradation in the Pelagic and Benthic Zone?

    Directory of Open Access Journals (Sweden)

    Andreas Eich

    Full Text Available The production of biodegradable plastic is increasing. Given the augmented littering of these products an increasing input into the sea is expected. Previous laboratory experiments have shown that degradation of plastic starts within days to weeks. Little is known about the early composition and activity of biofilms found on biodegradable and conventional plastic debris and its correlation to degradation in the marine environment. In this study we investigated the early formation of biofilms on plastic shopper bags and its consequences for the degradation of plastic. Samples of polyethylene and biodegradable plastic were tested in the Mediterranean Sea for 15 and 33 days. The samples were distributed equally to a shallow benthic (sedimentary seafloor at 6 m water depth and a pelagic habitat (3 m water depth to compare the impact of these different environments on fouling and degradation. The amount of biofilm increased on both plastic types and in both habitats. The diatom abundance and diversity differed significantly between the habitats and the plastic types. Diatoms were more abundant on samples from the pelagic zone. We anticipate that specific surface properties of the polymer types induced different biofilm communities on both plastic types. Additionally, different environmental conditions between the benthic and pelagic experimental site such as light intensity and shear forces may have influenced unequal colonisation between these habitats. The oxygen production rate was negative for all samples, indicating that the initial biofilm on marine plastic litter consumes oxygen, regardless of the plastic type or if exposed in the pelagic or the benthic zone. Mechanical tests did not reveal degradation within one month of exposure. However, scanning electron microscopy (SEM analysis displayed potential signs of degradation on the plastic surface, which differed between both plastic types. This study indicates that the early biofilm formation

  15. Synaptic plasticity in drug reward circuitry.

    Science.gov (United States)

    Winder, Danny G; Egli, Regula E; Schramm, Nicole L; Matthews, Robert T

    2002-11-01

    Drug addiction is a major public health issue worldwide. The persistence of drug craving coupled with the known recruitment of learning and memory centers in the brain has led investigators to hypothesize that the alterations in glutamatergic synaptic efficacy brought on by synaptic plasticity may play key roles in the addiction process. Here we review the present literature, examining the properties of synaptic plasticity within drug reward circuitry, and the effects that drugs of abuse have on these forms of plasticity. Interestingly, multiple forms of synaptic plasticity can be induced at glutamatergic synapses within the dorsal striatum, its ventral extension the nucleus accumbens, and the ventral tegmental area, and at least some of these forms of plasticity are regulated by behaviorally meaningful administration of cocaine and/or amphetamine. Thus, the present data suggest that regulation of synaptic plasticity in reward circuits is a tractable candidate mechanism underlying aspects of addiction.

  16. River plastic emissions to the world's oceans

    Science.gov (United States)

    Lebreton, Laurent C. M.; van der Zwet, Joost; Damsteeg, Jan-Willem; Slat, Boyan; Andrady, Anthony; Reisser, Julia

    2017-06-01

    Plastics in the marine environment have become a major concern because of their persistence at sea, and adverse consequences to marine life and potentially human health. Implementing mitigation strategies requires an understanding and quantification of marine plastic sources, taking spatial and temporal variability into account. Here we present a global model of plastic inputs from rivers into oceans based on waste management, population density and hydrological information. Our model is calibrated against measurements available in the literature. We estimate that between 1.15 and 2.41 million tonnes of plastic waste currently enters the ocean every year from rivers, with over 74% of emissions occurring between May and October. The top 20 polluting rivers, mostly located in Asia, account for 67% of the global total. The findings of this study provide baseline data for ocean plastic mass balance exercises, and assist in prioritizing future plastic debris monitoring and mitigation strategies.

  17. Biodegradability of Plastics: Challenges and Misconceptions.

    Science.gov (United States)

    Kubowicz, Stephan; Booth, Andy M

    2017-11-07

    Plastics are one of the most widely used materials and, in most cases, they are designed to have long life times. Thus, plastics contain a complex blend of stabilizers that prevent them from degrading too quickly. Unfortunately, many of the most advantageous properties of plastics such as their chemical, physical and biological inertness and durability present challenges when plastic is released into the environment. Common plastics such as polyethylene (PE), polypropylene (PP), polystyrene (PS), and polyethylene terephthalate (PET) are extremely persistent in the environment, where they undergo very slow fragmentation (projected to take centuries) into small particles through photo-, physical, and biological degradation processes 1 . The fragmentation of the material into increasingly smaller pieces is an unavoidable stage of the degradation process. Ultimately, plastic materials degrade to micron-sized particles (microplastics), which are persistent in the environment and present a potential source of harm for organisms.

  18. Lineage plasticity-mediated therapy resistance in prostate cancer.

    Science.gov (United States)

    Blee, Alexandra M; Huang, Haojie

    2018-06-12

    Therapy resistance is a significant challenge for prostate cancer treatment in clinic. Although targeted therapies such as androgen deprivation and androgen receptor (AR) inhibition are effective initially, tumor cells eventually evade these strategies through multiple mechanisms. Lineage reprogramming in response to hormone therapy represents a key mechanism that is increasingly observed. The studies in this area have revealed specific combinations of alterations present in adenocarcinomas that provide cells with the ability to transdifferentiate and perpetuate AR-independent tumor growth after androgen-based therapies. Interestingly, several master regulators have been identified that drive plasticity, some of which also play key roles during development and differentiation of the cell lineages in the normal prostate. Thus, further study of each AR-independent tumor type and understanding underlying mechanisms are warranted to develop combinational therapies that combat lineage plasticity in prostate cancer.

  19. Development of plastic scintillator based food radioactivity contamination monitoring system

    International Nuclear Information System (INIS)

    Parihar, A.; Sahani, R.M.; Mahala, V.K.; Vaijapurkar, S.G.

    2016-01-01

    Radioactivity is naturally present in soil, water and food stuffs. Food can be contaminated after discharge of radioactivity into the environment from industries that concentrate natural radionuclide and from civil or military nuclear operations. The contamination can be in three ways; by direct deposition, through the food chain and induced radioactivity due to exposure of high neutron flux. The health effects on human depend on the type of radionuclide and the length of time people are exposed to it. The studies of fission product behaviour in the food chain have revealed radionuclide Strontium-90, Caesium 137 and Iodine-131 are of major concern. Plastic scintillator is already developed indigenously at Defence Laboratory, Jodhpur. Efforts has been made to develop a portable field instrument using plastic scintillator for assessment of beta ( 90 Sr) and gamma ( 137 Cs and 131 I) radioactivity in food

  20. The premature necking of twinning-induced plasticity steels

    International Nuclear Information System (INIS)

    Yang, C.L.; Zhang, Z.J.; Zhang, P.; Zhang, Z.F.

    2017-01-01

    An unusual necking behavior was found in twinning-induced plasticity (TWIP) steels during tensile tests, which is quite different from that observed on most ductile metals. A sharp drop of the strain-hardening rate (Θ) arises before necking initiation, rather than after it, leading to the premature necking of TWIP steels. Through carefully examining the evolution of macroscopic defects at various tensile strains using three-dimensional X-ray tomography (3D-XRT), this premature necking behavior was attributed to the multiplication of macroscopic voids during plastic deformation. Combining with the previous theories and present characterizations on the evolution of macroscopic voids, the mechanism of the unusual necking behavior in TWIP steels was quantificationally revealed.

  1. Phyllosphere yeasts rapidly break down biodegradable plastics

    OpenAIRE

    Kitamoto, Hiroko K; Shinozaki, Yukiko; Cao, Xiao-hong; Morita, Tomotake; Konishi, Masaaki; Tago, Kanako; Kajiwara, Hideyuki; Koitabashi, Motoo; Yoshida, Shigenobu; Watanabe, Takashi; Sameshima-Yamashita, Yuka; Nakajima-Kambe, Toshiaki; Tsushima, Seiya

    2011-01-01

    The use of biodegradable plastics can reduce the accumulation of environmentally persistent plastic wastes. The rate of degradation of biodegradable plastics depends on environmental conditions and is highly variable. Techniques for achieving more consistent degradation are needed. However, only a few microorganisms involved in the degradation process have been isolated so far from the environment. Here, we show that Pseudozyma spp. yeasts, which are common in the phyllosphere and are easily ...

  2. Plastic Recycling Experiments in Materials Education

    Science.gov (United States)

    Liu, Ping; Waskom, Tommy L.

    1996-01-01

    The objective of this project was to introduce a series of plastic recycling experiments to students in materials-related courses such as materials science, material technology and materials testing. With the plastic recycling experiments, students not only can learn the fundamentals of plastic processing and properties as in conventional materials courses, but also can be exposed to the issue of materials life cycle and the impact on society and environment.

  3. Radiation resistance of plastic solid

    International Nuclear Information System (INIS)

    Moriyama, Noboru; Dojiri, Shigeru; Wadachi, Yoshiki

    1985-01-01

    The radiation from nucleides contained in solidified wates have some effects on the degradation of the solidification materials. This report deals with effects of such radiation on the mechanical strength of waste-plastics composites and on the generation of gasses. It is shown that the mechanical strength of polyethylene and polyester solids will not decrease at a total absorbed dose of 10 6 rad, a dose which a low-level waste composite is expected to receive during an infinite period of time. Rather, it increases in the case of polyethylene. The amount of gas generated from degraded polyethylene is about three times as large as that from polyester, namely, about 6 l per 200 l drum can at 10 6 rad. Hydrogen accounts for about 80 % of the total gas generated from polyethylene. On the other hand, the gas from polyester solid mainly contains hydrogen, carbon dioxide, carbon monoxide and methane, with a composition greatly dependent on the type of the waste contained. It is concluded from these results that plastic materials can serve satisfactorily as for as the effects of radiation on their mechanical strength and gas generation are concerned. A more important problem still remaining to be solved is the effects of radiation on the leaching of radioactive nuclides. (Nogami, K.)

  4. Waste product profile: Plastic film and bags

    Energy Technology Data Exchange (ETDEWEB)

    Miller, C. [Environmental Industry Associations, Washington, DC (United States)

    1996-10-01

    Plastic film is recycled by being pelletized following a granulation or densifying process. Manufacturing and converting plants are the major sources of plastic film for recycling because they can supply sufficient amounts of clean raw material of a known resin type. Post-consumer collection programs are more recent. They tend to focus on businesses such as grocery stores that are large generators of plastic bags. In this case, the recycling process is more complex, requiring sorting, washing, and removal of contaminants as a first step. Curbside collection of plastic bags is rare.

  5. Extruded plastic scintillator for MINERvA

    International Nuclear Information System (INIS)

    Pla-Dalmau, Anna; Bross, Alan D.; FermilabRykalin, Victor V.; Wood, Brian M.; NICADD, DeKalb

    2005-01-01

    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. 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. The D0 and MINOS experiments are already using extruded scintillator strips in their detectors. A new experiment at Fermilab is pursuing the use of extruded plastic scintillator. A new plastic scintillator strip is being tested and its properties characterized. The initial results are presented here

  6. Leaching of plastic additives to marine organisms

    International Nuclear Information System (INIS)

    Koelmans, Albert A.; Besseling, Ellen; Foekema, Edwin M.

    2014-01-01

    It is often assumed that ingestion of microplastics by aquatic species leads to increased exposure to plastic additives. However, experimental data or model based evidence is lacking. Here we assess the potential of leaching of nonylphenol (NP) and bisphenol A (BPA) in the intestinal tracts of Arenicola marina (lugworm) and Gadus morhua (North Sea cod). We use a biodynamic model that allows calculations of the relative contribution of plastic ingestion to total exposure of aquatic species to chemicals residing in the ingested plastic. Uncertainty in the most crucial parameters is accounted for by probabilistic modeling. Our conservative analysis shows that plastic ingestion by the lugworm yields NP and BPA concentrations that stay below the lower ends of global NP and BPA concentration ranges, and therefore are not likely to constitute a relevant exposure pathway. For cod, plastic ingestion appears to be a negligible pathway for exposure to NP and BPA. - Highlights: • Uptake of plastic additives after plastic ingestion was modeled for worms and fish. • This was done for bisphenol A and nonylphenol. • Uncertainty was accounted for by Monte Carlo simulations. • It appeared that exposure by plastic ingestion was negligible for fish. • Plastic ingestion may occasionally be relevant for marine worms. - Leaching of nonylphenol and bisphenol A from ingested microplastic may be relevant for the lugworm, but is irrelevant for fish like cod

  7. Environment friendly solutions of plastics waste management

    International Nuclear Information System (INIS)

    Pirzada, F.N.; Riffat, T.; Pirzada, M.D.S.

    1997-01-01

    The use of plastics is growing worldwide. Consequently, the volume of plastic waste is also increasing. Presently, more than 100 million tons per year of plastic is being produced globally. In U.S. alone more than 10 million tons of plastic is being dumped in landfills as waste, where it can persist for decades. This has resulted in exhausting old landfills. Public awareness on environment is also making it difficult to find new sites for landfills. This has led to increased emphasis on treatment and recycling of plastic wastes. Volume reduction of plastic waste has some unique problems. They arise from the intrinsic chemical inertness of polymeric materials and toxic nature of their degradation byproducts. The paper reviews the present state of plastic waste management including land filling, incineration and recycling technologies. The technical problems associated with each of these processes have been discussed. There is also brief description of ongoing R and D for finding improved methods of plastic waste handling with their promises and problems. The role of tougher legislation in developing better recycling methods and degradable plastics has also been evaluated. The claims made by the proponents of degradable polymers have also been critically reviewed. (authors)

  8. Neuronal cytoskeleton in synaptic plasticity and regeneration.

    Science.gov (United States)

    Gordon-Weeks, Phillip R; Fournier, Alyson E

    2014-04-01

    During development, dynamic changes in the axonal growth cone and dendrite are necessary for exploratory movements underlying initial axo-dendritic contact and ultimately the formation of a functional synapse. In the adult central nervous system, an impressive degree of plasticity is retained through morphological and molecular rearrangements in the pre- and post-synaptic compartments that underlie the strengthening or weakening of synaptic pathways. Plasticity is regulated by the interplay of permissive and inhibitory extracellular cues, which signal through receptors at the synapse to regulate the closure of critical periods of developmental plasticity as well as by acute changes in plasticity in response to experience and activity in the adult. The molecular underpinnings of synaptic plasticity are actively studied and it is clear that the cytoskeleton is a key substrate for many cues that affect plasticity. Many of the cues that restrict synaptic plasticity exhibit residual activity in the injured adult CNS and restrict regenerative growth by targeting the cytoskeleton. Here, we review some of the latest insights into how cytoskeletal remodeling affects neuronal plasticity and discuss how the cytoskeleton is being targeted in an effort to promote plasticity and repair following traumatic injury in the central nervous system. © 2013 International Society for Neurochemistry.

  9. 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.

  10. 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...

  11. Progresses in Polystyrene Biodegradation and Prospects for Solutions to Plastic Waste Pollution

    Science.gov (United States)

    Yang, S. S.; Brandon, A. M.; Xing, D. F.; Yang, J.; Pang, J. W.; Criddle, C. S.; Ren, N. Q.; Wu, W. M.

    2018-05-01

    Petroleum-based plastic pollution has been a global environmental concern for decades. The obvious contrast between the remarkable durability of the plastics and their short service time leads to the increasing accumulation of plastic wastes in the environment. A cost-effective, sustainable strategy to solve the problem should focus on source control and clean up. Polystyrene (PS) wastes, a recalcitrant plastic polymer, are among the wide spread man-made plastic pollutants. Destruction of PS wastes can be achieved using various abiotic methods such as incineration but such methods release potential air pollution and generation of hazardous by-products. Biodegradation and bioremediation has been proposed for years. Since the 1970’s, the microbial biodegradation of plastics, including PS, has been evaluated with mixed and isolated cultures from different sources such as activated sludge, trash, soil, and manure. To date, PS biodegradation by these microbial cultures is still quite slow. Recently, the larvae of yellow mealworms (Tenebrio molitor Linnaeus) have demonstrated promising PS biodegradation performance. Mealworms have demonstrated the ability to chew and ingest PS foam as food and are capable of degrading and mineralizing PS into CO2 via microbe-dependent activities within the gut in less than the 12-15 hrs gut retention time. These research results have revealed a potential for microbial biodegradation and bioremediation of plastic pollutants.

  12. Observational Study Unveils the Extensive Presence of Hazardous Elements in Beached Plastics from Lake Geneva

    Directory of Open Access Journals (Sweden)

    Montserrat Filella

    2018-02-01

    Full Text Available Over 3,000 samples of plastic litter have been retrieved from 12 pebble beaches around the shores of Lake Geneva. The plastic stock consisted of identifiable objects of various size and color, including bottles, bottle tops, cotton buds, pens, toys, and straws, an heterogeneous assortment of fragments whose origin was either discernible or unknown, and pieces or blocks of expanded polymer (polystyrene or polyurethane foam. Analysis of 670 samples by portable x-ray fluorescence (XRF spectrometry revealed high concentrations of hazardous elements or compounds among many plastics. These included Cd, Hg, and Pb (with maximum concentrations of 6,760, 810, and 23,500 ppm, respectively as stabilizers in PVC-based materials and/or brightly-colored sulfide or chromate pigments in primary and secondary plastics, and Br (with a maximum concentration of 27,400 ppm as a proxy for brominated flame retardants (BFRs in both plastics and foams. The abundance of hazardous elements in beached plastics that have been restricted or banned reflect the age and residence time of the plastic stock in the lake, coupled with a relatively high length of shoreline to surface area of the system. The migratability of hazardous elements from the polymeric matrix is likely to determine their environmental impacts and is recommended as a future area of research.

  13. Non-repeatability of large plasticity for Fe-based bulk metallic glasses

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Weiming [State Key Laboratory for Geomechanics and Deep Underground Engineering, School of Mechanics and Civil Engineering, School of Sciences, China University of Mining and Technology, Xuzhou 221116 (China); Sun, Baoan [Department of Mechanical and Biomedical Engineering, City University of Hong Kong (Hong Kong); Zhao, Yucheng, E-mail: zhaoyc1972@163.com [State Key Laboratory for Geomechanics and Deep Underground Engineering, School of Mechanics and Civil Engineering, School of Sciences, China University of Mining and Technology, Xuzhou 221116 (China); Li, Qiang [School of Physics Science and Technology, Xinjiang University, Urumqi, Xinjiang 830046 (China); Hou, Long; Luo, Ning [State Key Laboratory for Geomechanics and Deep Underground Engineering, School of Mechanics and Civil Engineering, School of Sciences, China University of Mining and Technology, Xuzhou 221116 (China); Dun, Chaochao [Department of Physics, Wake Forest University, Winston Salem, NC 27109 (United States); Zhao, Chengliang [Key Laboratory of Magnetic Materials and Devices, Ningbo Institute of Materials Technology & Engineering, Chinese Academy of Sciences, Ningbo 315201 (China); Ma, Zhanguo [State Key Laboratory for Geomechanics and Deep Underground Engineering, School of Mechanics and Civil Engineering, School of Sciences, China University of Mining and Technology, Xuzhou 221116 (China); Liu, Haishun, E-mail: liuhaishun@126.com [State Key Laboratory for Geomechanics and Deep Underground Engineering, School of Mechanics and Civil Engineering, School of Sciences, China University of Mining and Technology, Xuzhou 221116 (China); Shen, Baolong [School of Materials Science and Engineering, Southeast University, Nanjing 211189 (China)

    2016-08-15

    Serrated flow is an essential characteristic of the plastic deformation of metallic glasses. Under restricted loading conditions, the formation and expansion of shear bands act as the serrated flow of stress-strain curves in metallic glasses. In this work, serrated flows in Fe{sub 50}Ni{sub 30}P{sub 13}C{sub 7} glassy samples with different plasticity were studied. The distribution histogram shows a monotonically decreasing trend during the initial deformation stage (i.e., the plastic deformation in the range of 0–8%), whereas in the following deformation stage (i.e., a plastic deformation of 8–14%), the stress drop frequency distribution presents both a monotonically decreasing distribution and a peak shape similar to chaotic dynamics. It is shown that the spatial evolution behavior of shear bands in Fe{sub 50}Ni{sub 30}P{sub 13}C{sub 7} metallic glasses evolved from self-organized critical to chaotic dynamics in the form of serrated flow, which reveals the origin of discrete plasticity of Fe-based bulk metallic glasses. This study has potential applications for understanding the plastic deformation mechanism. - Highlights: • Two-stage deformation mechanism in Fe-based bulk metallic glasses. • Distribution of the stress drop amplitude is significantly different at two stages. • The stages are related to multiple shear bands and discrete plasticity.

  14. Non-repeatability of large plasticity for Fe-based bulk metallic glasses

    International Nuclear Information System (INIS)

    Yang, Weiming; Sun, Baoan; Zhao, Yucheng; Li, Qiang; Hou, Long; Luo, Ning; Dun, Chaochao; Zhao, Chengliang; Ma, Zhanguo; Liu, Haishun; Shen, Baolong

    2016-01-01

    Serrated flow is an essential characteristic of the plastic deformation of metallic glasses. Under restricted loading conditions, the formation and expansion of shear bands act as the serrated flow of stress-strain curves in metallic glasses. In this work, serrated flows in Fe_5_0Ni_3_0P_1_3C_7 glassy samples with different plasticity were studied. The distribution histogram shows a monotonically decreasing trend during the initial deformation stage (i.e., the plastic deformation in the range of 0–8%), whereas in the following deformation stage (i.e., a plastic deformation of 8–14%), the stress drop frequency distribution presents both a monotonically decreasing distribution and a peak shape similar to chaotic dynamics. It is shown that the spatial evolution behavior of shear bands in Fe_5_0Ni_3_0P_1_3C_7 metallic glasses evolved from self-organized critical to chaotic dynamics in the form of serrated flow, which reveals the origin of discrete plasticity of Fe-based bulk metallic glasses. This study has potential applications for understanding the plastic deformation mechanism. - Highlights: • Two-stage deformation mechanism in Fe-based bulk metallic glasses. • Distribution of the stress drop amplitude is significantly different at two stages. • The stages are related to multiple shear bands and discrete plasticity.

  15. 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...

  16. 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.

  17. 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.

  18. Motor cortical plasticity in Parkinson's disease.

    Science.gov (United States)

    Udupa, Kaviraja; Chen, Robert

    2013-09-04

    In Parkinson's disease (PD), there are alterations of the basal ganglia (BG) thalamocortical networks, primarily due to degeneration of nigrostriatal dopaminergic neurons. These changes in subcortical networks lead to plastic changes in primary motor cortex (M1), which mediates cortical motor output and is a potential target for treatment of PD. Studies investigating the motor cortical plasticity using non-invasive transcranial magnetic stimulation (TMS) have found altered plasticity in PD, but there are inconsistencies among these studies. This is likely because plasticity depends on many factors such as the extent of dopaminergic loss and disease severity, response to dopaminergic replacement therapies, development of l-DOPA-induced dyskinesias (LID), the plasticity protocol used, medication, and stimulation status in patients treated with deep brain stimulation (DBS). The influences of LID and DBS on BG and M1 plasticity have been explored in animal models and in PD patients. In addition, many other factors such age, genetic factors (e.g., brain derived neurotropic factor and other neurotransmitters or receptors polymorphism), emotional state, time of the day, physical fitness have been documented to play role in the extent of plasticity induced by TMS in human studies. In this review, we summarize the studies that investigated M1 plasticity in PD and demonstrate how these afore-mentioned factors affect motor cortical plasticity in PD. We conclude that it is important to consider the clinical, demographic, and technical factors that influence various plasticity protocols while developing these protocols as diagnostic or prognostic tools in PD. We also discuss how the modulation of cortical excitability and the plasticity with these non-invasive brain stimulation techniques facilitate the understanding of the pathophysiology of PD and help design potential therapeutic possibilities in this disorder.

  19. A study on the plasticity of soda-lime silica glass via molecular dynamics simulations

    Science.gov (United States)

    Urata, Shingo; Sato, Yosuke

    2017-11-01

    Molecular dynamics (MD) simulations were applied to construct a plasticity model, which enables one to simulate deformations of soda-lime silica glass (SLSG) by using continuum methods. To model the plasticity, stress induced by uniaxial and a variety of biaxial deformations was measured by MD simulations. We found that the surfaces of yield and maximum stresses, which are evaluated from the equivalent stress-strain curves, are reasonably represented by the Mohr-Coulomb ellipsoid. Comparing a finite element model using the constructed plasticity model to a large scale atomistic model on a nanoindentation simulation of SLSG reveals that the empirical method is accurate enough to evaluate the SLSG mechanical responses. Furthermore, the effect of ion-exchange on the SLSG plasticity was examined by using MD simulations. As a result, it was demonstrated that the effects of the initial compressive stress on the yield and maximum stresses are anisotropic contrary to our expectations.

  20. Dynamic plasticity in coupled avian midbrain maps

    Science.gov (United States)

    Atwal, Gurinder Singh

    2004-12-01

    Internal mapping of the external environment is carried out using the receptive fields of topographic neurons in the brain, and in a normal barn owl the aural and visual subcortical maps are aligned from early experiences. However, instantaneous misalignment of the aural and visual stimuli has been observed to result in adaptive behavior, manifested by functional and anatomical changes of the auditory processing system. Using methods of information theory and statistical mechanics a model of the adaptive dynamics of the aural receptive field is presented and analyzed. The dynamics is determined by maximizing the mutual information between the neural output and the weighted sensory neural inputs, admixed with noise, subject to biophysical constraints. The reduced costs of neural rewiring, as in the case of young barn owls, reveal two qualitatively different types of receptive field adaptation depending on the magnitude of the audiovisual misalignment. By letting the misalignment increase with time, it is shown that the ability to adapt can be increased even when neural rewiring costs are high, in agreement with recent experimental reports of the increased plasticity of the auditory space map in adult barn owls due to incremental learning. Finally, a critical speed of misalignment is identified, demarcating the crossover from adaptive to nonadaptive behavior.

  1. Developmental plasticity: re-conceiving the genotype.

    Science.gov (United States)

    Sultan, Sonia E

    2017-10-06

    In recent decades, the phenotype of an organism (i.e. its traits and behaviour) has been studied as the outcome of a developmental 'programme' coded in its genotype. This deterministic view is implicit in the Modern Synthesis approach to adaptive evolution as a sorting process among genetic variants. Studies of developmental pathways have revealed that genotypes are in fact differently expressed depending on environmental conditions. Accordingly, the genotype can be understood as a repertoire of potential developmental outcomes or norm of reaction. Reconceiving the genotype as an environmental response repertoire rather than a fixed developmental programme leads to three critical evolutionary insights. First, plastic responses to specific conditions often comprise functionally appropriate trait adjustments, resulting in an individual-level, developmental mode of adaptive variation. Second, because genotypes are differently expressed depending on the environment, the genetic diversity available to natural selection is itself environmentally contingent. Finally, environmental influences on development can extend across multiple generations via cytoplasmic and epigenetic factors transmitted to progeny individuals, altering their responses to their own, immediate environmental conditions and, in some cases, leading to inherited but non-genetic adaptations. Together, these insights suggest a more nuanced understanding of the genotype and its evolutionary role, as well as a shift in research focus to investigating the complex developmental interactions among genotypes, environments and previous environments.

  2. Properties of plastic filtration material

    Energy Technology Data Exchange (ETDEWEB)

    Paluch, W.

    1988-01-01

    Discusses properties of filters made of thermoplastic granulated material. The granulated plastic has a specific density of 10.3-10.6 kN/m/sup 3/ and a bulk density of about 6 kN/m/sup 3/. Its chemical resistance to acids, bases and salts is high but is it soluble in organic solvents. Filters made of this material are characterized by a porosity coefficient of 36.5% and a bulk density of 5.7-6.8 kN/m/sup 3/. Physical and mechanical properties of filter samples made of thermoplastic granulated material (50x50x50 mm) were investigated under laboratory conditions. Compression strength and influencing factors were analyzed (ambient temperature, manufacturing technology). Tests show that this filtration material developed by Poltegor is superior to other filtration materials used in Poland.

  3. ECM remodeling and its plasticity

    Science.gov (United States)

    Feng, Jingchen; Jones, Christopher A. R.; Cibula, Matthew; Mao, Xiaoming; Sander, Leonard M.; Levine, Herbert; Sun, Bo

    The mechanical interactions between cells and Extracellular Matrix (ECM) are of great importance in many cellular processes. These interactions are reciprocal, i.e. contracting cells pull and reorganize the surrounding matrix, while the remodeled matrix feeds back to regulate cell activities. Recent experiments show in collagen gels with densely distributed cells, aligned fiber bundles are formed in the direction between neighboring cells. Fibers flow into the center region between contracting cell pairs in this process, which causes the concentration of fibers in the fiber bundles to become significantly enhanced. Using an extended lattice-based model, we show that viscoelasticity plays an essential role in ECM remodeling and contributes to the enhanced concentration in fiber bundles. We further characterize ECM plasticity within our model and verify our results with rheometer experiments.

  4. Circuit design on plastic foils

    CERN Document Server

    Raiteri, Daniele; Roermund, Arthur H M

    2015-01-01

    This book illustrates a variety of circuit designs on plastic foils and provides all the information needed to undertake successful designs in large-area electronics.  The authors demonstrate architectural, circuit, layout, and device solutions and explain the reasons and the creative process behind each. Readers will learn how to keep under control large-area technologies and achieve robust, reliable circuit designs that can face the challenges imposed by low-cost low-temperature high-throughput manufacturing.   • Discusses implications of problems associated with large-area electronics and compares them to standard silicon; • Provides the basis for understanding physics and modeling of disordered material; • Includes guidelines to quickly setup the basic CAD tools enabling efficient and reliable designs; • Illustrates practical solutions to cope with hard/soft faults, variability, mismatch, aging and bias stress at architecture, circuit, layout, and device levels.

  5. Vascular plasticity in cerebrovascular disorders

    DEFF Research Database (Denmark)

    Edvinsson, Lars I H; Povlsen, Gro Klitgaard

    2011-01-01

    and microvessels that takes place after different types of stroke. Receptors like the endothelin type B, angiotensin type 1, and 5-hydroxytryptamine type 1B/1D receptors are upregulated in the smooth muscle layer of cerebral arteries after different types of ischemic stroke as well as after subarachnoid hemorrhage......Cerebral ischemia remains a major cause of morbidity and mortality with little advancement in subacute treatment options. This review aims to cover and discuss novel insight obtained during the last decade into plastic changes in the vasoconstrictor receptor profiles of cerebral arteries...... therapeutic target for prevention of vasoconstrictor receptor upregulation after stroke. Together, those findings provide new perspectives on the pathophysiology of ischemic stroke and point toward a novel way of reducing vasoconstriction, neuronal cell death, and thus neurologic deficits after stroke....

  6. AUGMENTATION-RELATED BRAIN PLASTICITY

    Directory of Open Access Journals (Sweden)

    Giovanni eDi Pino

    2014-06-01

    Full Text Available Today, the anthropomorphism of the tools and the development of neural interfaces require reconsidering the concept of human-tools interaction in the framework of human augmentation. This review analyzes the plastic process that the brain undergoes when it comes into contact with augmenting artificial sensors and effectors and, on the other hand, the changes that the use of external augmenting devices produces in the brain.Hitherto, few studies investigated the neural correlates of augmentation, but clues on it can be borrowed from logically-related paradigms: sensorimotor training, cognitive enhancement, cross-modal plasticity, sensorimotor functional substitution, use and embodiment of tools.Augmentation modifies function and structure of a number of areas, i.e. primary sensory cortices shape their receptive fields to become sensitive to novel inputs. Motor areas adapt the neuroprosthesis representation firing-rate to refine kinematics. As for normal motor outputs, the learning process recruits motor and premotor cortices and the acquisition of proficiency decreases attentional recruitment, focuses the activity on sensorimotor areas and increases the basal ganglia drive on the cortex. Augmentation deeply relies on the frontoparietal network. In particular, premotor cortex is involved in learning the control of an external effector and owns the tool motor representation, while the intraparietal sulcus extracts its visual features. In these areas, multisensory integration neurons enlarge their receptive fields to embody supernumerary limbs. For operating an anthropomorphic neuroprosthesis, the mirror system is required to understand the meaning of the action, the cerebellum for the formation of its internal model and the insula for its interoception. In conclusion, anthropomorphic sensorized devices can provide the critical sensory afferences to evolve the exploitation of tools through their embodiment, reshaping the body representation and the

  7. Cyclic Plastic Deformation and Welding Simulation

    NARCIS (Netherlands)

    Ten Horn, C.H.L.J.

    2003-01-01

    One of the concerns of a fitness for purpose analysis is the quantification of the relevant material properties. It is known from experiments that the mechanical properties of a material can change due to a monotonic plastic deformation or a cyclic plastic deformation. For a fitness for purpose

  8. 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.

  9. Plastic Accumulation in the Mediterranean Sea

    KAUST Repository

    Có zar, André s; Sanz-Martí n, Marina; Martí , Elisa; Gonzá lez-Gordillo, J. Ignacio; Ubeda, Bá rbara; Gá lvez, José Á .; Irigoien, Xabier; Duarte, Carlos M.

    2015-01-01

    Concentrations of floating plastic were measured throughout the Mediterranean Sea to assess whether this basin can be regarded as a great accumulation region of plastic debris. We found that the average density of plastic (1 item per 4 m2), as well as its frequency of occurrence (100% of the sites sampled), are comparable to the accumulation zones described for the five subtropical ocean gyres. Plastic debris in the Mediterranean surface waters was dominated by millimeter-sized fragments, but showed a higher proportion of large plastic objects than that present in oceanic gyres, reflecting the closer connection with pollution sources. The accumulation of floating plastic in the Mediterranean Sea (between 1,000 and 3,000 tons) is likely related to the high human pressure together with the hydrodynamics of this semi-enclosed basin, with outflow mainly occurring through a deep water layer. Given the biological richness and concentration of economic activities in the Mediterranean Sea, the affects of plastic pollution on marine and human life are expected to be particularly frequent in this plastic accumulation region.

  10. Mixed gas plasticization phenomena in asymmetric membranes

    NARCIS (Netherlands)

    Visser, Tymen

    2006-01-01

    This thesis describes the thorough investigation of mixed gas transport behavior of asymmetric membranes in the separation of feed streams containing plasticizing gases in order to gain more insights into the complicated behavior of plasticization. To successfully employ gas separation membranes in

  11. Candidate genes in ocular dominance plasticity

    NARCIS (Netherlands)

    Rietman, M.L.; Sommeijer, J.-P.; Levelt, C.N.; Heimel, J.A.; Brussaard, A.B.; Borst, J.G.G.; Elgersma, Y.; Galjart, N.; van der Horst, G.T.; Pennartz, C.M.; Smit, A.B.; Spruijt, B.M.; Verhage, M.; de Zeeuw, C.I.

    2012-01-01

    Many studies have been devoted to the identification of genes involved in experience-dependent plasticity in the visual cortex. To discover new candidate genes, we have reexamined data from one such study on ocular dominance (OD) plasticity in recombinant inbred BXD mouse strains. We have correlated

  12. Plastic accumulation in the Mediterranean sea.

    Directory of Open Access Journals (Sweden)

    Andrés Cózar

    Full Text Available Concentrations of floating plastic were measured throughout the Mediterranean Sea to assess whether this basin can be regarded as a great accumulation region of plastic debris. We found that the average density of plastic (1 item per 4 m2, as well as its frequency of occurrence (100% of the sites sampled, are comparable to the accumulation zones described for the five subtropical ocean gyres. Plastic debris in the Mediterranean surface waters was dominated by millimeter-sized fragments, but showed a higher proportion of large plastic objects than that present in oceanic gyres, reflecting the closer connection with pollution sources. The accumulation of floating plastic in the Mediterranean Sea (between 1,000 and 3,000 tons is likely related to the high human pressure together with the hydrodynamics of this semi-enclosed basin, with outflow mainly occurring through a deep water layer. Given the biological richness and concentration of economic activities in the Mediterranean Sea, the affects of plastic pollution on marine and human life are expected to be particularly frequent in this plastic accumulation region.

  13. Residual stresses in plastic random systems

    NARCIS (Netherlands)

    Alava, M.J.; Karttunen, M.E.J.; Niskanen, K.J.

    1995-01-01

    We show that yielding in elastic plastic materials creates residual stresses when local disorder is present. The intensity of these stresses grows with the external stress and degree of initial disorder. The one-dimensional model we employ also yields a discontinuous transition to perfect plasticity

  14. Plastic biliary stents for malignant biliary diseases

    NARCIS (Netherlands)

    Huibregtse, Inge; Fockens, Paul

    2011-01-01

    Plastic biliary endoprostheses have not changed much since their introduction more than 3 decades ago. Although their use has been challenged by the introduction of metal stents, plastic stents still remain commonly used. Much work has been done to improve the problem of stent obstruction but

  15. Plastic soep komt op ons bord

    NARCIS (Netherlands)

    Franeker, van J.A.

    2011-01-01

    De wereldwijd verspreide 'soep' van kleine plastic deeltjes in zeeën en oceanen vormt een omvangrijk mondiaal milieuprobleem. Niet alleen leidt het plastic tot verstrikking en verstopping bij vogels en vissen, ook brengt de giftigheid van de materie de voedselketen in gevaar. Om te voorkomen dat die

  16. Undergraduate Plastic Surgery Education: Problems, Challenges ...

    African Journals Online (AJOL)

    based on principles rather than limited procedures, with surgical interventions ranging from complex microsurgery-based reconstructions to aesthetic procedures. However, medical students' perceptions of the field of plastic surgery are limited and underestimate the versatility of services offered by plastic surgeons.[1,2] In ...

  17. Plastic collapse load of corroded steel plates

    Indian Academy of Sciences (India)

    Keywords. Corroded steel plate; plastic collapse; FEM; rough surface. ... The main aim of present work is to study plastic collapse load of corroded steel plates with irregular surfaces under tension. Non-linear finite element method ... Department of Ocean Engineering, AmirKabir University of Technology, 15914 Tehran, Iran ...

  18. Liquid crystal displays with plastic substrates

    Science.gov (United States)

    Lueder, Ernst H.

    1998-04-01

    Plastic substrates for the cells of displays exhibit only 1/6 of the weight of glass substrates; they are virtually unbreakable; their flexibility allows the designer to give them a shape suppressing reflections, to realize a display board on a curved surface or meeting the requirements for an appealing styling; displays with plastics are thinner which provides a wider viewing angle. These features render them attractive for displays in portable systems such as mobile phones, pagers, smart cards, personal digital assistants (PDAs) and portable computers. Reflective displays are especially attractive as they don't need a back light. The most important requirements are the protection of plastics against gas permeation and chemical agents, the prevention of layers on plastics to crack or peel off when the plastic is bent and the development of low temperature thin film processes because the plastics, as a rule, only tolerate temperatures below 150 degrees Celsius. Bistable reflective FLC- and PSCT-displays with plastic substrates will be introduced. Special sputtered SiO2-orientation layers preserve the displayed information even if pressure or torsion is applied. MIM-addressed PDLC-displays require additional Al- or Ti-layers which provide the necessary ductility. Sputtered or PECVD-generated TFTs can be fabricated on plastics at temperatures below 150 degrees Celsius.

  19. COMPOSITES FROM RECYCLED WOOD AND PLASTICS

    Science.gov (United States)

    The ultimate goal of this research was to develop technology to convert recycled wood fiber and plastics into durable products that are recyclable and otherwise environmentally friendly. Two processing technologies were used to prepare wood-plastic composites: air-laying and melt...

  20. Biological degradation of plastics: a comprehensive review.

    Science.gov (United States)

    Shah, Aamer Ali; Hasan, Fariha; Hameed, Abdul; Ahmed, Safia

    2008-01-01

    Lack of degradability and the closing of landfill sites as well as growing water and land pollution problems have led to concern about plastics. With the excessive use of plastics 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. Awareness of the waste problem and its impact on the environment has awakened new interest in the area of degradable polymers. The interest in environmental issues is growing and there are increasing demands to develop material which do not burden the environment significantly. Biodegradation is necessary for water-soluble or water-immiscible polymers because they eventually enter streams which can neither be recycled nor incinerated. It is important to consider the microbial degradation of natural and synthetic polymers in order to understand what is necessary for biodegradation and the mechanisms involved. This requires understanding of the interactions between materials and microorganisms and the biochemical changes involved. Widespread studies on the biodegradation of plastics have been carried out in order to overcome the environmental problems associated with synthetic plastic waste. This paper reviews the current research on the biodegradation of biodegradable and also the conventional synthetic plastics and also use of various techniques for the analysis of degradation in vitro.

  1. Marine Debris and Plastic Source Reduction Toolkit

    Science.gov (United States)

    Many plastic food service ware items originate on college and university campuses—in cafeterias, snack rooms, cafés, and eateries with take-out dining options. This Campus Toolkit is a detailed “how to” guide for reducing plastic waste on college campuses.

  2. Studies of elastic-plastic instabilities

    DEFF Research Database (Denmark)

    Tvergaard, Viggo

    1999-01-01

    Analyses of plastic instabilities are reviewed, with focus on results in structural mechanics as well as continuum mechanics. First the basic theories for bifurcation and post-bifurcation behavior are briefly presented. Then, localization of plastic flow is discussed, including shear band formati...

  3. 49 CFR 192.59 - Plastic pipe.

    Science.gov (United States)

    2010-10-01

    ... Other Regulations Relating to Transportation (Continued) PIPELINE AND HAZARDOUS MATERIALS SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) PIPELINE SAFETY TRANSPORTATION OF NATURAL AND OTHER GAS BY PIPELINE: MINIMUM FEDERAL SAFETY STANDARDS Materials § 192.59 Plastic pipe. (a) New plastic pipe...

  4. Do dwarf chameleons ( Bradypodion ) show developmental plasticity?

    African Journals Online (AJOL)

    It has been hypothesized that B. melanocephalum and B. thamnobates may be phenotypically plastic populations of the same species, since environmental conditions, the driving force behind developmental plasticity, varies between the distributions of these two allopatric taxa.We raised juveniles of both species under ...

  5. Plastic zonder olie : lesmodule voor nieuwe scheikunde

    NARCIS (Netherlands)

    Langejan, B.; Klein Douwel, C.; Horst, ter J.J.; Tijdink, K.; Marle, van N.; Klaasen, P.; Coolen, R.; Assenbergh, van P.; Sijbers, J.P.J.; Mast, A.

    2013-01-01

    Lesmodule voor nieuwe scheikunde voor leerlingen uit 5 en 6 vwo. Bioplastics worden gemaakt uit natuurlijke grondstoffen. Als ze de synthetische plastics vervangen kan de voorraad aardolie ontzien worden. Omdat veel bioplastics afbreekbaar zijn, kan ook de berg plastic afval krimpen. Maar zijn

  6. Integrating Hebbian and homeostatic plasticity: introduction.

    Science.gov (United States)

    Fox, Kevin; Stryker, Michael

    2017-03-05

    Hebbian plasticity is widely considered to be the mechanism by which information can be coded and retained in neurons in the brain. Homeostatic plasticity moves the neuron back towards its original state following a perturbation, including perturbations produced by Hebbian plasticity. How then does homeostatic plasticity avoid erasing the Hebbian coded information? To understand how plasticity works in the brain, and therefore to understand learning, memory, sensory adaptation, development and recovery from injury, requires development of a theory of plasticity that integrates both forms of plasticity into a whole. In April 2016, a group of computational and experimental neuroscientists met in London at a discussion meeting hosted by the Royal Society to identify the critical questions in the field and to frame the research agenda for the next steps. Here, we provide a brief introduction to the papers arising from the meeting and highlight some of the themes to have emerged from the discussions.This article is part of the themed issue 'Integrating Hebbian and homeostatic plasticity'. © 2017 The Author(s).

  7. Robust Return Algorithm for Anisotropic Plasticity Models

    DEFF Research Database (Denmark)

    Tidemann, L.; Krenk, Steen

    2017-01-01

    Plasticity models can be defined by an energy potential, a plastic flow potential and a yield surface. The energy potential defines the relation between the observable elastic strains ϒe and the energy conjugate stresses Τe and between the non-observable internal strains i and the energy conjugat...

  8. Demonstrating Fluorescence with Neon Paper and Plastic

    Science.gov (United States)

    Birriel, Jennifer J.; Roe, Clarissa

    2015-01-01

    Several papers in this journal have dealt with the fluorescence in orange neon plastic, olive oil, and soda. In each case, the fluorescent emission was excited by either green or violet-blue laser light. In this paper, we examine the fluorescent emission spectra of so-called neon colored papers and plastic clipboards available in department and…

  9. 7 CFR 58.348 - Plastic cream.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 3 2010-01-01 2010-01-01 false Plastic cream. 58.348 Section 58.348 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Standards... Products Bearing Usda Official Identification § 58.348 Plastic cream. The flavor shall be sweet, pleasing...

  10. What is behind the plastic strain rate?

    NARCIS (Netherlands)

    Hütter, M.; Grmela, M.; Öttinger, H.C.

    2009-01-01

    The plastic strain rate plays a central role in macroscopic models on elasto-viscoplasticity. In order to discuss the concept behind this quantity, we propose, first, a kinetic toy model to describe the dynamics of sliding layers representative of plastic deformation of single crystalline metals.

  11. Plastic Accumulation in the Mediterranean Sea

    Science.gov (United States)

    Cózar, Andrés; Sanz-Martín, Marina; Martí, Elisa; González-Gordillo, J. Ignacio; Ubeda, Bárbara; Gálvez, José Á.; Irigoien, Xabier; Duarte, Carlos M.

    2015-01-01

    Concentrations of floating plastic were measured throughout the Mediterranean Sea to assess whether this basin can be regarded as a great accumulation region of plastic debris. We found that the average density of plastic (1 item per 4 m2), as well as its frequency of occurrence (100% of the sites sampled), are comparable to the accumulation zones described for the five subtropical ocean gyres. Plastic debris in the Mediterranean surface waters was dominated by millimeter-sized fragments, but showed a higher proportion of large plastic objects than that present in oceanic gyres, reflecting the closer connection with pollution sources. The accumulation of floating plastic in the Mediterranean Sea (between 1,000 and 3,000 tons) is likely related to the high human pressure together with the hydrodynamics of this semi-enclosed basin, with outflow mainly occurring through a deep water layer. Given the biological richness and concentration of economic activities in the Mediterranean Sea, the affects of plastic pollution on marine and human life are expected to be particularly frequent in this plastic accumulation region. PMID:25831129

  12. Plastic Accumulation in the Mediterranean Sea

    KAUST Repository

    Cózar, Andrés

    2015-04-01

    Concentrations of floating plastic were measured throughout the Mediterranean Sea to assess whether this basin can be regarded as a great accumulation region of plastic debris. We found that the average density of plastic (1 item per 4 m2), as well as its frequency of occurrence (100% of the sites sampled), are comparable to the accumulation zones described for the five subtropical ocean gyres. Plastic debris in the Mediterranean surface waters was dominated by millimeter-sized fragments, but showed a higher proportion of large plastic objects than that present in oceanic gyres, reflecting the closer connection with pollution sources. The accumulation of floating plastic in the Mediterranean Sea (between 1,000 and 3,000 tons) is likely related to the high human pressure together with the hydrodynamics of this semi-enclosed basin, with outflow mainly occurring through a deep water layer. Given the biological richness and concentration of economic activities in the Mediterranean Sea, the affects of plastic pollution on marine and human life are expected to be particularly frequent in this plastic accumulation region.

  13. Allergic contact dermatitis to plastic banknotes.

    Science.gov (United States)

    Mohamed, M; Delaney, T A; Horton, J J

    1999-08-01

    Allergic contact dermatitis to ultraviolet (UV) cured acrylates occurs predominantly in occupationally exposed workers. Two men presented with dermatitis coinciding with the location of banknotes in their pockets. Patch testing confirmed allergic contact dermatitis to multiple acrylates and Australian plastic banknotes. This is the first report of contact allergy to acrylates present in Australian plastic banknotes.

  14. Industrial plastics waste: Identification and segregation

    Science.gov (United States)

    Widener, Edward L.

    1990-01-01

    Throwaway plastic products, mainly packaging, are inundating our landfills and incinerators. Most are ethenic thermoplastics, which can be recycled as new products or fossil-fuels. Lab experiments are described, involving destructive and non-destructive tests for identifying and using plastics. The burn-test, with simple apparatus and familiar samples, is recommended as quick, cheap and effective.

  15. Plastic accumulation in the Mediterranean sea.

    Science.gov (United States)

    Cózar, Andrés; Sanz-Martín, Marina; Martí, Elisa; González-Gordillo, J Ignacio; Ubeda, Bárbara; Gálvez, José Á; Irigoien, Xabier; Duarte, Carlos M

    2015-01-01

    Concentrations of floating plastic were measured throughout the Mediterranean Sea to assess whether this basin can be regarded as a great accumulation region of plastic debris. We found that the average density of plastic (1 item per 4 m2), as well as its frequency of occurrence (100% of the sites sampled), are comparable to the accumulation zones described for the five subtropical ocean gyres. Plastic debris in the Mediterranean surface waters was dominated by millimeter-sized fragments, but showed a higher proportion of large plastic objects than that present in oceanic gyres, reflecting the closer connection with pollution sources. The accumulation of floating plastic in the Mediterranean Sea (between 1,000 and 3,000 tons) is likely related to the high human pressure together with the hydrodynamics of this semi-enclosed basin, with outflow mainly occurring through a deep water layer. Given the biological richness and concentration of economic activities in the Mediterranean Sea, the affects of plastic pollution on marine and human life are expected to be particularly frequent in this plastic accumulation region.

  16. Tiny plastic lung mimics human pulmonary function

    Science.gov (United States)

    Careers Inclusion & Diversity Work-Life Balance Career Resources Apply for a Job Postdocs Students Goals Recycling Green Purchasing Pollution Prevention Reusing Water Resources Environmental Management Releases - 2016 » April » Tiny plastic lung mimics human pulmonary function Tiny plastic lung mimics

  17. 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.

  18. Bibliometric trend analyses of plastic surgery research

    NARCIS (Netherlands)

    Loonen, M.P.J.

    2007-01-01

    The present thesis was designed to evaluate the qualitative and quantitative aspects of plastic surgery research by means of a bibliometric citation analysis of plastic surgical presentations and publications. Citations to such published work provides an indication of the impact and the relevance of

  19. A linear model of ductile plastic damage

    International Nuclear Information System (INIS)

    Lemaitre, J.

    1983-01-01

    A three-dimensional model of isotropic ductile plastic damage based on a continuum damage variable on the effective stress concept and on thermodynamics is derived. As shown by experiments on several metals and alloys, the model, integrated in the case of proportional loading, is linear with respect to the accumulated plastic strain and shows a large influence of stress triaxiality [fr

  20. Reliability of Elasto-Plastic Structural Systems

    DEFF Research Database (Denmark)

    Delmar, M. V.; Sørensen, John Dalsgaard

    1990-01-01

    This paper proposes a method for generating safety margins and failure mode equations for elasto-plastic structures where interaction of load effects is taken into account. Structural failure is defined by large nodal displacements or plastic collapse. A branch-and-bound technique is used...

  1. The Persistence of Utopia: Plasticity and Difference from Roland Barthes to Catherine Malabou

    Directory of Open Access Journals (Sweden)

    Jennifer A. Wagner-Lawlor

    2017-12-01

    Full Text Available The theorizing of utopia is a persistent theme throughout several generations of the French continental tradition, and alongside the process theory of Alfred North Whitehead to a large degree recuperates the concept of utopia from its supposed dismissal by Marx and his intellectual descendants. Most recently, attention to the notion of plasticity, popularized (relatively speaking by Catherine Malabou, extends speculation on utopian possibility.  Compelled to answer to Marx’s denigration of utopia as fantasy, the tendency was (still is, for many to compensate for the absence of a programmatic politics by stressing what is “useful” about utopian dreaming, and therefore where or how exactly a utopian text reveals or creates political drive, or motivates political action. In this essay, I argue that theorists have overlooked the use of utopia as not only the reproduction of difference, or what Malabou calls positive plasticity, but also as, therefore, a disruption; Malabou might prefer the term accident here. Tracing the concept of plasticity from Roland Barthes to Malabou, with a nod at Miguel Abensour, this essay teases out the links between a contemporary notion of plasticity to argue, simply put, that utopia is plastic. This plasticity of the concept ensures its political force. These links, obscured in the essay “Plastic,” Barthes makes only later in his writing. But for Malabou, plasticity underlies a principle of futurity and/as generativity, such that new forms, new meanings, new concepts emerge through difference. Utopia’s horizons of potentiality depend on difference, and on non-achievement. Finally, I argue that the persistence of utopia (Abensour as a form of thinking is the most important, and political, effect of utopian plasticity.

  2. 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...

  3. 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.

  4. [Survey of plasticizers in polyvinyl chloride toys].

    Science.gov (United States)

    Abe, Yutaka; Yamaguchi, Miku; Mutsuga, Motoh; Hirahara, Yoshichika; Kawamura, Yoko

    2012-01-01

    Plasticizers in 101 samples of polyvinyl chloride (PVC) toys on the Japanese market were surveyed. No phthalates were detected in designated toys, though bis(2-ethylhexyl)phthalate, diisononyl phthalate, diisobutyl phthalate, dibutyl phthalate, diisodecyl phthalate and benzyl butyl phthalate were detected in more than half of other toys. 2,2,4-Tributyl-1,3-pentanediol diisobutylate, o-acetyl tributyl citrate, adipates and diacetyl lauroyl glycerol, which are alternative plasticizers to phthalates, were detected. The results of structural analysis confirmed the presence of di(2-ethylhexyl)terephthalate, tributyl citrate, diisononyl 1,2-cyclohexanedicarboxylate and neopentyl glycol esters; these have not previonsly been reported in Japan. There appears to be a shift in plasticizers used for designated toys from phthalates to new plasticizers, and the number of different plasticizers is increasing.

  5. Phyllosphere yeasts rapidly break down biodegradable plastics.

    Science.gov (United States)

    Kitamoto, Hiroko K; Shinozaki, Yukiko; Cao, Xiao-Hong; Morita, Tomotake; Konishi, Masaaki; Tago, Kanako; Kajiwara, Hideyuki; Koitabashi, Motoo; Yoshida, Shigenobu; Watanabe, Takashi; Sameshima-Yamashita, Yuka; Nakajima-Kambe, Toshiaki; Tsushima, Seiya

    2011-11-29

    The use of biodegradable plastics can reduce the accumulation of environmentally persistent plastic wastes. The rate of degradation of biodegradable plastics depends on environmental conditions and is highly variable. Techniques for achieving more consistent degradation are needed. However, only a few microorganisms involved in the degradation process have been isolated so far from the environment. Here, we show that Pseudozyma spp. yeasts, which are common in the phyllosphere and are easily isolated from plant surfaces, displayed strong degradation activity on films made from poly-butylene succinate or poly-butylene succinate-co-adipate. Strains of P. antarctica isolated from leaves and husks of paddy rice displayed strong degradation activity on these films at 30°C. The type strain, P. antarctica JCM 10317, and Pseudozyma spp. strains from phyllosphere secreted a biodegradable plastic-degrading enzyme with a molecular mass of about 22 kDa. Reliable source of biodegradable plastic-degrading microorganisms are now in our hands.

  6. Plasticity of pressure-sensitive materials

    CERN Document Server

    Ochsner, Andreas

    2014-01-01

    Classical plasticity theory of metals is independent of the hydrostatic pressure. However, if the metal contains voids or pores or if the structure is composed of cells, this classical assumption is no more valid and the influence of the hydrostatic pressure must be incorporated in the constitutive description. Looking at the microlevel, metal plasticity is connected with the uniform planes of atoms organized with long-range order. Planes may slip past each other along their close-packed directions. The result is a permanent change of shape within the crystal and plastic deformation. The presence of dislocations increases the likelihood of planes slipping. Nowadays, the theory of pressure sensitive plasticity is successfully applied to many other important classes of materials (polymers, concrete, bones etc.) even if the phenomena on the micro-level are different to classical plasticity of metals. The theoretical background of this phenomenological approach based on observations on the macro-level is describe...

  7. Nanoparticles from Degradation of Biodegradable Plastic Mulch

    Science.gov (United States)

    Flury, Markus; Sintim, Henry; Bary, Andy; English, Marie; Schaefer, Sean

    2017-04-01

    Plastic mulch films are commonly used in crop production. They provide multiple benefits, including control of weeds and insects, increase of soil and air temperature, reduction of evaporation, and prevention of soil erosion. The use of plastic mulch film in agriculture has great potential to increase food production and security. Plastic mulch films must be retrieved and disposed after usage. Biodegradable plastic mulch films, who can be tilled into the soil after usage offer great benefits as alternative to conventional polyethylene plastic. However, it has to be shown that the degradation of these mulches is complete and no micro- and nanoparticles are released during degradation. We conducted a field experiment with biodegradable mulches and tested mulch degradation. Mulch was removed from the field after the growing season and composted to facilitate degradation. We found that micro- and nanoparticles were released during degradation of the mulch films in compost. This raises concerns about degradation in soils as well.

  8. Energy recycling of plastic and rubber wastes

    International Nuclear Information System (INIS)

    Hussain, R.

    2003-01-01

    Major areas for applications of plastics and rubbers are building and construction, packaging, transportation, automobiles, furniture, house wares, appliances, electrical and electronics. Approximately 20% of all the plastics produced are utilized by the building and construction industry/sup (1-3)/. Categories of polymers mostly used in the above industries include poly (vinyl chloride), polypropylene, polyethylene, polystyrene phenolics, acrylics and urethanes. Tyres and tubes are almost exclusively made up of rubbers. One third of total consumption of plastics finds applications, like films, bottles and packaging, in food-products that have a maximum life-span of two years, after which these find way to waste dumps. As the polymer industry in Pakistan is set to grow very rapidly in the near future the increase in utilization of plastic products in synchronous with the advent of computers and information technology. About 0.60 Kg per capita of waste generated daily in Lahore /(7.14)/ contains considerable quantity of plastics. (AB)

  9. 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)

  10. 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.

  11. 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

  12. Stacking fault tetrahedron induced plasticity in copper single crystal

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Liang, E-mail: lz592@uowmail.edu.au [School of Mechanical, Materials and Mechatronic Engineering, University of Wollongong, Wollongong, NSW 2522 (Australia); Lu, Cheng, E-mail: chenglu@uow.edu.au [School of Mechanical, Materials and Mechatronic Engineering, University of Wollongong, Wollongong, NSW 2522 (Australia); Tieu, Kiet; Su, Lihong; Zhao, Xing [School of Mechanical, Materials and Mechatronic Engineering, University of Wollongong, Wollongong, NSW 2522 (Australia); Pei, Linqing [Department of Mechanical Engineering, Chongqing University, Chongqing 400044 (China)

    2017-01-05

    Stacking fault tetrahedron (SFT) is the most common type of vacancy clustered defects in fcc metals and alloys, and can play an important role in the mechanical properties of metallic materials. In this study, molecular dynamics (MD) simulations were carried out to investigate the incipience of plasticity and the underlying atomic mechanisms in copper single crystals with SFT. Different deformation mechanisms of SFT were reported due to the crystal orientations and loading directions (compression and tension). The results showed that the incipient plasticity in crystals with SFT resulted from the heterogeneous dislocation nucleation from SFT, so the stress required for plastic deformation was less than that needed for perfect single crystals. Three crystal orientations ([1 0 0], [1 1 0] and [1 1 1]) were specified in this study because they can represent most of the typical deformation mechanisms of SFT. MD simulations revealed that the structural transformation of SFT was frequent under the applied loading; a metastable SFT structure and the collapse of SFT were usually observed. The structural transformation resulted in a different reduction of yield stress in compression and tension, and also caused a decreased or reversed compression/tension asymmetry. Compressive stress can result in the unfaulting of Frank loop in some crystal orientations. According to the elastic theory of dislocation, the process of unfaulting was closely related to the size of the dislocation loop and the stacking fault energy.

  13. 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.

  14. A strain gradient plasticity theory with application to wire torsion

    KAUST Repository

    Liu, J. X.; El Sayed, Tamer S.

    2014-01-01

    Based on the framework of the existing strain gradient plasticity theories, we have examined three kinds of relations for the plastic strain dependence of the material intrinsic length scale, and thus developed updated strain gradient plasticity

  15. 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.

  16. Morphological analysis of thermoplastic starch films and montmorillonite (TPS/MMT) using vegetable oils of Brazilian Cerrado as plasticizers

    International Nuclear Information System (INIS)

    Schlemmer, Daniela; Sales, Maria Jose A.; Angelica, Romulo S.; Gomes, Ana Cristina M.M.

    2009-01-01

    Biopolymers can be used where petrochemical plastics have applications with short life. The excellent degradation of starch and its low cost make it an alternative for obtaining biodegradable plastics. To obtain thermoplastic starch (TPS) is necessary mechanical shake, high temperature and plasticizers. In this work, TPS were produced using three different vegetable oils from Brazilian's cerrado as plasticizers: buriti, macauba or pequi. Materials are also produced with montmorillonite (MMT). All the materials were analyzed by scanning electronic microscopy (SEM) and X-ray diffraction (XRD). The starch micrographs revealed irregular delaminate with a predominance of starch and 'holes' for the oils. In nanocomposites the clusters of clay are dispersed without a defined standard. It was understood that the plasticizers and processing completely changed the structure of starch causing a decrease in their crystallinity degree. Almost all nanocomposites presented exfoliate structure, only one presented intercalated structure. (author)

  17. Technical specifications for mechanical recycling of agricultural plastic waste.

    Science.gov (United States)

    Briassoulis, D; Hiskakis, M; Babou, E

    2013-06-01

    Technical specifications appropriate for the recycling of agricultural plastic wastes (APWs), widely accepted by the recycling industry were developed. The specifications establish quality standards to be met by the agricultural plastics producers, users and the agricultural plastic waste management chain. They constitute the base for the best economical and environmental valorisation of the APW. The analysis of the APW streams conducted across Europe in the framework of the European project "LabelAgriWaste" revealed the inherent characteristics of the APW streams and the inherent constraints (technical or economical) of the APW. The APW stream properties related to its recycling potential and measured during pilot trials are presented and a subsequent universally accepted simplified and expanded list of APW recycling technical specifications is proposed and justified. The list includes two sets of specifications, applied to two different quality categories of recyclable APW: one for pellet production process ("Quality I") and another one for plastic profile production process ("Quality II"). Parameters that are taken into consideration in the specifications include the APW physical characteristics, contamination, composition and degradation. The proposed specifications are focused on polyethylene based APW that represents the vast majority of the APW stream. However, the specifications can be adjusted to cover also APW of different materials (e.g. PP or PVC) that are found in very small quantities in protected cultivations in Europe. The adoption of the proposed specifications could transform this waste stream into a labelled commodity traded freely in the market and will constitute the base for the best economical and environmental valorisation of the APW. Copyright © 2013 Elsevier Ltd. All rights reserved.

  18. Plastic debris in the open ocean

    KAUST Repository

    Cozar, Andres

    2014-06-30

    There is a rising concern regarding the accumulation of floating plastic debris in the open ocean. However, the magnitude and the fate of this pollution are still open questions. Using data from the Malaspina 2010 circumnavigation, regional surveys, and previously published reports, we show a worldwide distribution of plastic on the surface of the open ocean, mostly accumulating in the convergence zones of each of the five subtropical gyres with comparable density. However, the global load of plastic on the open ocean surface was estimated to be on the order of tens of thousands of tons, far less than expected. Our observations of the size distribution of floating plastic debris point at important size-selective sinks removing millimeter-sized fragments of floating plastic on a large scale. This sink may involve a combination of fast nano-fragmentation of the microplastic into particles of microns or smaller, their transference to the ocean interior by food webs and ballasting processes, and processes yet to be discovered. Resolving the fate of the missing plastic debris is of fundamental importance to determine the nature and significance of the impacts of plastic pollution in the ocean.

  19. Plastic debris in the open ocean.

    Science.gov (United States)

    Cózar, Andrés; Echevarría, Fidel; González-Gordillo, J Ignacio; Irigoien, Xabier; Ubeda, Bárbara; Hernández-León, Santiago; Palma, Alvaro T; Navarro, Sandra; García-de-Lomas, Juan; Ruiz, Andrea; Fernández-de-Puelles, María L; Duarte, Carlos M

    2014-07-15

    There is a rising concern regarding the accumulation of floating plastic debris in the open ocean. However, the magnitude and the fate of this pollution are still open questions. Using data from the Malaspina 2010 circumnavigation, regional surveys, and previously published reports, we show a worldwide distribution of plastic on the surface of the open ocean, mostly accumulating in the convergence zones of each of the five subtropical gyres with comparable density. However, the global load of plastic on the open ocean surface was estimated to be on the order of tens of thousands of tons, far less than expected. Our observations of the size distribution of floating plastic debris point at important size-selective sinks removing millimeter-sized fragments of floating plastic on a large scale. This sink may involve a combination of fast nano-fragmentation of the microplastic into particles of microns or smaller, their transference to the ocean interior by food webs and ballasting processes, and processes yet to be discovered. Resolving the fate of the missing plastic debris is of fundamental importance to determine the nature and significance of the impacts of plastic pollution in the ocean.

  20. The future of A-150 TE plastic

    International Nuclear Information System (INIS)

    Goodman, L.J.

    1985-01-01

    For the past 26 years a large number of laboratories have constructed or purchased ionization chambers, proportional counters, and phantoms made of A-150 tissue-equivalent plastic, and they have amassed a considerable amount of data and experience in its properties and uses. The United States National Bureau of Standards is now considering the desirability of supplying A-150 plastic as a research material with a certified homogeneity. We are, however, faced with a problem since the nylon used in A-150 has been discontinued by the manufacturer and the current stock of A-150 has been estimated to be adequate to supply the demand for only the next 2 or 3 years. Thus, it will be necessary to reformulate the plastic mixture we will be using in the future. This situation offers us the opportunity to change the composition of tissue-equivalent plastic to better conform to present-day requirements. To elucidate just what these requirements are, we have conducted a postal survey of the opinions of neutron dosimetrists and the results are presented and discussed. It is concluded that the present A-150 plastic and a future tissue-equivalent plastic formulation should be made research materials, and that a future tissue-equivalent plastic should be made to conform as closely as possible to the soft tissue composition given in ICRU Report 33

  1. Modeling plasticity by non-continuous deformation

    Science.gov (United States)

    Ben-Shmuel, Yaron; Altus, Eli

    2017-10-01

    Plasticity and failure theories are still subjects of intense research. Engineering constitutive models on the macroscale which are based on micro characteristics are very much in need. This study is motivated by the observation that continuum assumptions in plasticity in which neighbour material elements are inseparable at all-time are physically impossible, since local detachments, slips and neighbour switching must operate, i.e. non-continuous deformation. Material microstructure is modelled herein by a set of point elements (particles) interacting with their neighbours. Each particle can detach from and/or attach with its neighbours during deformation. Simulations on two- dimensional configurations subjected to uniaxial compression cycle are conducted. Stochastic heterogeneity is controlled by a single "disorder" parameter. It was found that (a) macro response resembles typical elasto-plastic behaviour; (b) plastic energy is proportional to the number of detachments; (c) residual plastic strain is proportional to the number of attachments, and (d) volume is preserved, which is consistent with macro plastic deformation. Rigid body displacements of local groups of elements are also observed. Higher disorder decreases the macro elastic moduli and increases plastic energy. Evolution of anisotropic effects is obtained with no additional parameters.

  2. Smart film actuators using biomass plastic

    International Nuclear Information System (INIS)

    Yoneyama, Satoshi; Tanaka, Nobuo

    2011-01-01

    This paper presents a novel smart film actuator based on the use of a biomass plastic as a piezoelectric film. Conventional polymeric smart sensors and actuators have been based upon synthetic piezoelectric polymer films such as PVDF. Almost all synthetic polymers are made from nearly depleted oil resources. In addition combustion of their materials releases carbon dioxide, thereby contributing to global warming. Thus at least two important sustainability principles are violated when employing synthetic polymers: avoiding depletable resources and avoiding ecosystem destruction. To overcome such problems, industrial plastic products made from synthetic polymers were developed to replace oil-based plastics with biomass plastics. This paper applies a biomass plastic with piezoelectricity such as poly-L-lactic acid (PLLA). As a result, PLLA film becomes a distributed parameter actuator per se, hence an environmentally conscious smart film actuator is developed. Firstly, this paper overviews the fundamental properties of piezoelectric synthetic polymers and biopolymers. The concept of carbon neutrality using biopolymers is mentioned. Then a two-dimensional modal actuator for exciting a specific structural mode is proposed. Furthermore, a biomass plastic-based cantilever beam with the capability of modal actuation is developed, the validity of the proposed smart film actuator based upon a biomass plastic being analytically as well as experimentally verified

  3. Plastic debris in the open ocean

    Science.gov (United States)

    Cózar, Andrés; Echevarría, Fidel; González-Gordillo, J. Ignacio; Irigoien, Xabier; Úbeda, Bárbara; Hernández-León, Santiago; Palma, Álvaro T.; Navarro, Sandra; García-de-Lomas, Juan; Ruiz, Andrea; Fernández-de-Puelles, María L.; Duarte, Carlos M.

    2014-01-01

    There is a rising concern regarding the accumulation of floating plastic debris in the open ocean. However, the magnitude and the fate of this pollution are still open questions. Using data from the Malaspina 2010 circumnavigation, regional surveys, and previously published reports, we show a worldwide distribution of plastic on the surface of the open ocean, mostly accumulating in the convergence zones of each of the five subtropical gyres with comparable density. However, the global load of plastic on the open ocean surface was estimated to be on the order of tens of thousands of tons, far less than expected. Our observations of the size distribution of floating plastic debris point at important size-selective sinks removing millimeter-sized fragments of floating plastic on a large scale. This sink may involve a combination of fast nano-fragmentation of the microplastic into particles of microns or smaller, their transference to the ocean interior by food webs and ballasting processes, and processes yet to be discovered. Resolving the fate of the missing plastic debris is of fundamental importance to determine the nature and significance of the impacts of plastic pollution in the ocean. PMID:24982135

  4. Aktau Plastics Plant Explosives Material Report

    Energy Technology Data Exchange (ETDEWEB)

    CASE JR.,ROGER S.

    1999-12-01

    The U.S. Department of Energy (DOE) has been cooperating with the Republic of Kazakhstanin Combined Threat Reduction (CTR) activities at the BN350 reactor located at the Mangyshlak Atomic Energy Complex (MAEC) in the city of Aktau, Kazakhstan since 1994. DOE contract personnel have been stationed at this facility for the last two years and DOE representatives regularly visit this location to oversee the continuing cooperative activities. Continued future cooperation is planned. A Russian news report in September 1999 indicated that 75 metric tons of organic peroxides stored at the Plastics Plant near Aktau were in danger of exploding and killing or injuring nearby residents. To ensure the health and safety of the personnel at the BN350 site, the DOE conducted a study to investigate the potential danger to the BN350 site posed by these materials at the Plastics Plant. The study conclusion was that while the organic peroxides do have hazards associated with them, the BN350 site is a safe distance from the Plastics Plant. Further, because the Plastics Plant and MAEC have cooperative fire-fighting agreements,and the Plastics Plant had exhausted its reserve of fire-fighting foam, there was the possibility of the Plastics Plant depleting the store of fire-fighting foam at the BN350 site. Subsequently, the DOE decided to purchase fire-fighting foam for the Plastics Plant to ensure the availability of free-fighting foam at the BN350 site.

  5. Microbial Enzymatic Degradation of Biodegradable Plastics.

    Science.gov (United States)

    Roohi; Bano, Kulsoom; Kuddus, Mohammed; Zaheer, Mohammed R; Zia, Qamar; Khan, Mohammed F; Ashraf, Ghulam Md; Gupta, Anamika; Aliev, Gjumrakch

    2017-01-01

    The renewable feedstock derived biodegradable plastics are important in various industries such as packaging, agricultural, paper coating, garbage bags and biomedical implants. The increasing water and waste pollution due to the available decomposition methods of plastic degradation have led to the emergence of biodegradable plastics and biological degradation with microbial (bacteria and fungi) extracellular enzymes. The microbes utilize biodegradable polymers as the substrate under starvation and in unavailability of microbial nutrients. Microbial enzymatic degradation is suitable from bioremediation point of view as no waste accumulation occurs. It is important to understand the microbial interaction and mechanism involved in the enzymatic degradation of biodegradable plastics under the influence of several environmental factors such as applied pH, thermo-stability, substrate molecular weight and/or complexity. To study the surface erosion of polymer film is another approach for hydrolytic degradation characteristion. The degradation of biopolymer is associated with the production of low molecular weight monomer and generation of carbon dioxide, methane and water molecule. This review reported the degradation study of various existing biodegradable plastics along with the potent degrading microbes (bacteria and fungi). Patents available on plastic biodegradation with biotechnological significance is also summarized in this paper. This paper assesses that new disposal technique should be adopted for the degradation of polymers and further research is required for the economical production of biodegradable plastics along with their enzymatic degradation. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

  6. Methodology for plastic fracture - a progress report

    International Nuclear Information System (INIS)

    Wilkinson, J.P.D.; Smith, R.E.E.

    1977-01-01

    This paper describes the progress of a study to develop a methodology for plastic fracture. Such a fracture mechanics methodology, having application in the plastic region, is required to assess the margin of safety inherent in nuclear reactor pressure vessels. The initiation and growth of flaws in pressure vessels under overload conditions is distinguished by a number of unique features, such as large scale yielding, three-dimensional structural and flaw configurations, and failure instabilities that may be controlled by either toughness or plastic flow. In order to develop a broadly applicable methodology of plastic fracture, these features require the following analytical and experimental studies: development of criteria for crack initiation and growth under large scale yielding; the use of the finite element method to describe elastic-plastic behaviour of both the structure and the crack tip region; and extensive experimental studies on laboratory scale and large scale specimens, which attempt to reproduce the pertinent plastic flow and crack growth phenomena. This discussion centers on progress to date on the selection, through analysis and laboratory experiments, of viable criteria for crack initiation and growth during plastic fracture. (Auth.)

  7. Pregnancy and the Plastic Surgery Resident.

    Science.gov (United States)

    Garza, Rebecca M; Weston, Jane S; Furnas, Heather J

    2017-01-01

    Combining pregnancy with plastic surgery residency has historically been difficult. Two decades ago, 36 percent of plastic surgery program directors surveyed actively discouraged pregnancy among residents, and 33 percent of women plastic surgeons suffered from infertility. Most alarmingly, 26 percent of plastic surgery trainees had had an elective abortion during residency. With increasing numbers of women training in plastic surgery, this historical lack of support for pregnancy deserves further attention. To explore the current accommodations made for the pregnant plastic surgery resident, an electronic survey was sent to 88 plastic surgery program directors in the United States. Fifty-four responded, for a response rate of 61.36 percent. On average, a director trained a total of 7.91 women among 17.28 residents trained over 8.19 years. Of the women residents, 1.43 were pregnant during a director's tenure, with 1.35 of those residents taking maternity leave. An average 1.75 male residents took paternity leave. Approximately one-third of programs had a formal maternity/paternity leave policy (36.54 percent) which, in most cases, was limited to defining allowed weeks of leave, time required to fulfill program requirements, and remuneration during leave. This survey of plastic surgery directors is a first step in defining the challenges training programs face in supporting the pregnant resident. Directors provided comments describing their challenges accommodating an absent resident in a small program and complying with the American Board of Plastic Surgery's required weeks of training per year. A discussion of these challenges is followed by suggested solutions.

  8. [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.

  9. 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 ).

  10. Recrystallization induced plasticity in austenite and ferrite

    International Nuclear Information System (INIS)

    Huang Mingxin; Pineau, André; Bouaziz, Olivier; Vu, Trong-Dai

    2012-01-01

    Highlights: ► Plasticity can be induced by recrystallization in austenite and ferrite. ► Strain rate is proportional to recrystallization kinetics. ► Overall atomic flux selects a preferential direction may be the origin. - Abstract: New experimental evidences are provided to demonstrate that plastic strain can be induced by recrystallization in austenite and ferrite under an applied stress much smaller than their yield stresses. Such Recrystallization Induced Plasticity (RIP) phenomenon occurs because the overall atomic flux during recrystallization follows a preferential direction imposed by the applied stress.

  11. New plastic plane stress model for concrete

    International Nuclear Information System (INIS)

    Winnicki, A.; Cichon, Cz.

    1993-01-01

    In the paper a description of concrete behaviour in the plane stress case is given on the basis of the modified bounding surface plasticity theory. Three independent plastic mechanisms have been introduced describing axiatoric and deviatoric plastic strains and their coupling. All the new analytical formulae for material functions being in agreement with experiments and loading/unloading criteria have been proposed. In addition, for the proper description of concrete behaviour in tension a new, separate function of bounding surface shrinkage has been introduced. (author)

  12. Plastic deformation of 2D crumpled wires

    International Nuclear Information System (INIS)

    Gomes, M A F; Donato, C C; Brito, V P; Coelho, A S O

    2008-01-01

    When a single long piece of elastic wire is injected through channels into a confining two-dimensional cavity, a complex structure of hierarchical loops is formed. In the limit of maximum packing density, these structures are described by several scaling laws. In this paper this packing process is investigated but using plastic wires which give rise to completely irreversible structures of different morphology. In particular, the plastic deformation from circular to oblate configurations of crumpled wires is experimentally studied, obtained by the application of an axial strain. Among other things, it is shown that in spite of plasticity, irreversibility and very large deformations, scaling is still observed.

  13. Estimation of the Reliability of Plastic Slabs

    DEFF Research Database (Denmark)

    Pirzada, G. B. : Ph.D.

    In this thesis, work related to fundamental conditions has been extended to non-fundamental or the general case of probabilistic analysis. Finally, using the ss-unzipping technique a door has been opened to system reliability analysis of plastic slabs. An attempt has been made in this thesis...... to give a probabilistic treatment of plastic slabs which is parallel to the deterministic and systematic treatment of plastic slabs by Nielsen (3). The fundamental reason is that in Nielsen (3) the treatment is based on a deterministic modelling of the basic material properties for the reinforced...

  14. SLEEP AND OLFACTORY CORTICAL PLASTICITY

    Directory of Open Access Journals (Sweden)

    Dylan eBarnes

    2014-04-01

    Full Text Available In many systems, sleep plays a vital role in memory consolidation and synaptic homeostasis. These processes together help store information of biological significance and reset synaptic circuits to facilitate acquisition of information in the future. In this review, we describe recent evidence of sleep-dependent changes in olfactory system structure and function which contribute to odor memory and perception. During slow-wave sleep, the piriform cortex becomes hypo-responsive to odor stimulation and instead displays sharp-wave activity similar to that observed within the hippocampal formation. Furthermore, the functional connectivity between the piriform cortex and other cortical and limbic regions is enhanced during slow-wave sleep compared to waking. This combination of conditions may allow odor memory consolidation to occur during a state of reduced external interference and facilitate association of odor memories with stored hedonic and contextual cues. Evidence consistent with sleep-dependent odor replay within olfactory cortical circuits is presented. These data suggest that both the strength and precision of odor memories is sleep-dependent. The work further emphasizes the critical role of synaptic plasticity and memory in not only odor memory but also basic odor perception. The work also suggests a possible link between sleep disturbances that are frequently co-morbid with a wide range of pathologies including Alzheimer’s disease, schizophrenia and depression and the known olfactory impairments associated with those disorders.

  15. Plastic deformation of indium nanostructures

    International Nuclear Information System (INIS)

    Lee, Gyuhyon; Kim, Ju-Young; Burek, Michael J.; Greer, Julia R.; Tsui, Ting Y.

    2011-01-01

    Highlights: → Indium nanopillars display two different deformation mechanisms. → ∼80% exhibited low flow stresses near that of bulk indium. → Low strength nanopillars have strain rate sensitivity similar to bulk indium. → ∼20% of compressed indium nanopillars deformed at nearly theoretical strengths. → Low-strength samples do not exhibit strength size effects. - Abstract: Mechanical properties and morphology of cylindrical indium nanopillars, fabricated by electron beam lithography and electroplating, are characterized in uniaxial compression. Time-dependent deformation and influence of size on nanoscale indium mechanical properties were investigated. The results show two fundamentally different deformation mechanisms which govern plasticity in these indium nanostructures. We observed that the majority of indium nanopillars deform at engineering stresses near the bulk values (Type I), with a small fraction sustaining flow stresses approaching the theoretical limit for indium (Type II). The results also show the strain rate sensitivity and flow stresses in Type I indium nanopillars are similar to bulk indium with no apparent size effects.

  16. Plasticity of spermatogonial stem cells

    Directory of Open Access Journals (Sweden)

    Paul S Cooke

    2015-06-01

    Full Text Available There have been significant breakthroughs over the past decade in the development and use of pluripotent stem cells as a potential source of cells for applications in regenerative medicine. It is likely that this methodology will begin to play an important role in human clinical medicine in the years to come. This review describes the plasticity of one type of pluripotent cell, spermatogonial stem cells (SSCs, and their potential therapeutic applications in regenerative medicine and male infertility. Normally, SSCs give rise to sperm when in the testis. However, both human and murine SSCs can give rise to cells with embryonic stem (ES cell-like characteristics that can be directed to differentiate into tissues of all three embryonic germ layers when placed in an appropriate inductive microenvironment, which is in contrast to other postnatal stem cells. Previous studies have reported that SSCs expressed an intermediate pluripotent phenotype before differentiating into a specific cell type and that extended culture was necessary for this to occur. However, recent studies from our group using a tissue recombination model demonstrated that SSCs differentiated rapidly into another tissue, in this case, prostatic epithelium, without expression of pluripotent ES cell markers before differentiation. These results suggest that SSCs are capable of directly differentiating into other cell types without going through an intermediate ES cell-like stage. Because SSCs do not require reprogramming to achieve a pluripotent state, they are an attractive source of pluripotent cells for use in regenerative medicine.

  17. A Plastic Bottle in Rectosigmoid

    Directory of Open Access Journals (Sweden)

    A. Derakhshanfar

    2007-07-01

    Full Text Available Introduction: Evaluation and treatment of foreign bodies in rectum involves careful history and physical examination. The cases of forced introduction of the objects most commonly are , sexual assault , self – introduced for anal eroticism and accidental insertion.Case Report: We describe a case of a patient with rectal impaction following self administration of a plastic bottle for anal sexual gratification. A 49 years old man was admitted in the emergency department with the history of self introduced a bottle into his rectum physical examination and abdominal X-Ray diagnosed the case as impacted foreign body in rectosigmoid. An attempt was made to deliver the bottle through the rectum but because of high lying big bottle in the sigmoid laporotomy was performed and the bottle was removed though a longitudinal incision on sigmoid colon.Conclusion: Retained rectosigmoid foreign bodies have been encountered more frequently and present a dilemma for management and rarely laporotomy for extraction of foreign bodies was performed.

  18. Functional outcomes following lesions in visual cortex: Implications for plasticity of high-level vision.

    Science.gov (United States)

    Liu, Tina T; Behrmann, Marlene

    2017-10-01

    Understanding the nature and extent of neural plasticity in humans remains a key challenge for neuroscience. Importantly, however, a precise characterization of plasticity and its underlying mechanism has the potential to enable new approaches for enhancing reorganization of cortical function. Investigations of the impairment and subsequent recovery of cognitive and perceptual functions following early-onset cortical lesions in humans provide a unique opportunity to elucidate how the brain changes, adapts, and reorganizes. Specifically, here, we focus on restitution of visual function, and we review the findings on plasticity and re-organization of the ventral occipital temporal cortex (VOTC) in published reports of 46 patients with a lesion to or resection of the visual cortex early in life. Findings reveal that a lesion to the VOTC results in a deficit that affects the visual recognition of more than one category of stimuli (faces, objects and words). In addition, the majority of pediatric patients show limited recovery over time, especially those in whom deficits in low-level vision also persist. Last, given that neither the equipotentiality nor the modularity view on plasticity was clearly supported, we suggest some intermediate possibilities in which some plasticity may be evident but that this might depend on the area that was affected, its maturational trajectory as well as its structural and functional connectivity constraints. Finally, we offer suggestions for future research that can elucidate plasticity further. Copyright © 2017 Elsevier Ltd. All rights reserved.

  19. Intermittent hypoxia, respiratory plasticity and sleep apnea in humans: present knowledge and future investigations.

    Science.gov (United States)

    Mateika, Jason H; Syed, Ziauddin

    2013-09-15

    This review examines the role that respiratory plasticity has in the maintenance of breathing stability during sleep in individuals with sleep apnea. The initial portion of the review considers the manner in which repetitive breathing events may be initiated in individuals with sleep apnea. Thereafter, the role that two forms of respiratory plasticity, progressive augmentation of the hypoxic ventilatory response and long-term facilitation of upper airway and respiratory muscle activity, might have in modifying breathing events in humans is examined. In this context, present knowledge regarding the initiation of respiratory plasticity in humans during wakefulness and sleep is addressed. Also, published findings which reveal that exposure to intermittent hypoxia promotes breathing instability, at least in part, because of progressive augmentation of the hypoxic ventilatory response and the absence of long-term facilitation, are considered. Next, future directions are presented and are focused on the manner in which forms of plasticity that stabilize breathing might be promoted while diminishing destabilizing forms, concurrently. These future directions will consider the potential role of circadian rhythms in the promotion of respiratory plasticity and the role of respiratory plasticity in enhancing established treatments for sleep apnea. Published by Elsevier B.V.

  20. Intermittent hypoxia, respiratory plasticity and sleep apnea in humans; present knowledge and future investigations

    Science.gov (United States)

    Mateika, Jason H.; Syed, Ziauddin

    2013-01-01

    This review examines the role that respiratory plasticity has in the maintenance of breathing stability during sleep in individuals with sleep apnea. The initial portion of the review considers the manner in which repetitive breathing events may be initiated in individuals with sleep apnea. Thereafter, the role that two forms of respiratory plasticity, progressive augmentation of the hypoxic ventilatory response and long-term facilitation of upper airway and respiratory muscle activity, might have in modifying breathing events in humans is examined. In this context, present knowledge regarding the initiation of respiratory plasticity in humans during wakefulness and sleep is addressed. Also, published findings which reveal that exposure to intermittent hypoxia promotes breathing instability, at least in part, because of progressive augmentation of the hypoxic ventilatory response and the absence of long-term facilitation, are considered. Next, future directions are presented and are focused on the manner in which forms of plasticity that stabilize breathing might be promoted while diminishing destabilizing forms, concurrently. These future directions will consider the potential role of circadian rhythms in the promotion of respiratory plasticity and the role of respiratory plasticity in enhancing established treatments for sleep apnea. PMID:23587570

  1. An experimental study on usage of plastic oil and B20 algae biodiesel blend as substitute fuel to diesel engine.

    Science.gov (United States)

    Ramesha, D K; Kumara, G Prema; Lalsaheb; Mohammed, Aamir V T; Mohammad, Haseeb A; Kasma, Mufteeb Ain

    2016-05-01

    Usage of plastics has been ever increasing and now poses a tremendous threat to the environment. Millions of tons of plastics are produced annually worldwide, and the waste products have become a common feature at overflowing bins and landfills. The process of converting waste plastic into value-added fuels finds a feasible solution for recycling of plastics. Thus, two universal problems such as problems of waste plastic management and problems of fuel shortage are being tackled simultaneously. Converting waste plastics into fuel holds great promise for both the environmental and economic scenarios. In order to carry out the study on plastic wastes, the pyrolysis process was used. Pyrolysis runs without oxygen and in high temperature of about 250-300 °C. The fuel obtained from plastics is blended with B20 algae oil, which is a biodiesel obtained from microalgae. For conducting the various experiments, a 10-HP single-cylinder four-stroke direct-injection water-cooled diesel engine is employed. The engine is made to run at 1500 rpm and the load is varied gradually from 0 to 100 %. The performance, emission and combustion characteristics are observed. The BTE was observed to be higher with respect to diesel for plastic-biodiesel blend and biodiesel blend by 15.7 and 12.9 %, respectively, at full load. For plastic-biodiesel blend, the emission of UBHC and CO decreases with a slight increase in NO x as compared to diesel. It reveals that fuel properties are comparable with petroleum products. Also, the process of converting plastic waste to fuel has now turned the problems into an opportunity to make wealth from waste.

  2. Genome plasticity and systems evolution in Streptomyces

    Science.gov (United States)

    2012-01-01

    Background Streptomycetes are filamentous soil-dwelling bacteria. They are best known as the producers of a great variety of natural products such as antibiotics, antifungals, antiparasitics, and anticancer agents and the decomposers of organic substances for carbon recycling. They are also model organisms for the studies of gene regulatory networks, morphological differentiation, and stress response. The availability of sets of genomes from closely related Streptomyces strains makes it possible to assess the mechanisms underlying genome plasticity and systems adaptation. Results We present the results of a comprehensive analysis of the genomes of five Streptomyces species with distinct phenotypes. These streptomycetes have a pan-genome comprised of 17,362 orthologous families which includes 3,096 components in the core genome, 5,066 components in the dispensable genome, and 9,200 components that are uniquely present in only one species. The core genome makes up about 33%-45% of each genome repertoire. It contains important genes for Streptomyces biology including those involved in gene regulation, secretion, secondary metabolism and morphological differentiation. Abundant duplicate genes have been identified, with 4%-11% of the whole genomes composed of lineage-specific expansions (LSEs), suggesting that frequent gene duplication or lateral gene transfer events play a role in shaping the genome diversification within this genus. Two patterns of expansion, single gene expansion and chromosome block expansion are observed, representing different scales of duplication. Conclusions Our results provide a catalog of genome components and their potential functional roles in gene regulatory networks and metabolic networks. The core genome components reveal the minimum requirement for streptomycetes to sustain a successful lifecycle in the soil environment, reflecting the effects of both genome evolution and environmental stress acting upon the expressed phenotypes. A

  3. Elastic-plastic transition: A universal law

    Directory of Open Access Journals (Sweden)

    Chen Zhong

    2016-01-01

    Full Text Available Although the initial stress-strain behavior in a tensile test is often characterized as linear elastic up to a yield stress and nonlinear plastic thereafter, the pre-yield transition region is known to exhibit significant curvature and hysteresis. Hundreds of high-precision loading-unloading-loading tensile tests were performed using 26 commercial sheet alloys exhibiting a wide range of strength, ductility and crystal structure. Analysis of the results reveals the following: 1.There is no significant linear elastic region; the proportional limit is ~0 MPa when measured with sufficient sensitivity. 2.Each of the hundreds of measured transitional stress-strain curves can be characterized by a single parameter, here called the “modulus reduction rate.”The corresponding equation captures ~80% of the observed variation, a factor of 3 to 6 better than a one-parameter linear approximation. 3.Most interestingly, the transitional behavior for all alloys follows a “Universal Law” requiring no fit parameters. The law depends only upon the strength of the material and its Young’s modulus, both of which are can be measured by independent tests or adopted from handbooks. The Universal Law captures ~90% of the variation represented by the one-parameter representation and eliminates the need for mechanical testing to implement and apply. The practical and theoretical implications of these results are discussed. The results provide a simple path to significantly improving applied constitutive models in the transitional regime. The consistency of the effect for such a wide range of metals and suggests that the origin of the behavior lies in the pile-up and relaxation of dislocation arrays.

  4. Measures for recycling plastic wastes in France

    Energy Technology Data Exchange (ETDEWEB)

    Cossais, J C [Ministere de l' Industrie et de la Recherche, 75 - Paris (France). Delegation aux Economies de Matieres Premieres

    1978-05-01

    Raw materials crisis and environmental awareness have lead to the question of intensively dealing with the recycling of plastics. Although plastic wastes (residues) industrially occuring have been recycled for a long time, this is certainly not always the case in the subsequent stages. One must particularly give thought to the considerable quantities of agricultural and municipal wastes. Besides the problem of collecting the waste which can only be satisfactorily solved by separate collection or setting up sorting places, it is necessary for the recycling plastic wastes on a large scale to find or develop sellable products. The product for sale is limited by economical aspects and prejudices against recycled materials. The public have taken to a series of measures in France to simplify recycling plastic wastes. Private industry is also beginning to take interest in this new sources of raw materials.

  5. Fundamentals of the theory of plasticity

    CERN Document Server

    Kachanov, L M

    2004-01-01

    Intended for use by advanced engineering students and professionals, this volume focuses on plastic deformation of metals at normal temperatures, as applied to strength of machines and structures. 1971 edition.

  6. Vapor pressure measured with inflatable plastic bag

    Science.gov (United States)

    1965-01-01

    Deflated plastic bag in a vacuum chamber measures initial low vapor pressures of materials. The bag captures the test sample vapors and visual observation of the vapor-inflated bag under increasing external pressures yields pertinent data.

  7. Thermoset plastics for the nuclear track detection

    International Nuclear Information System (INIS)

    Fujii, M.

    1984-01-01

    Characteristics of thermoset plastics for the nuclear track detection have been studied. Some of the samples show good etching properties and will be useful for observations of super heavy primaries. (author)

  8. Plasticity of cortical excitatory-inhibitory balance.

    Science.gov (United States)

    Froemke, Robert C

    2015-07-08

    Synapses are highly plastic and are modified by changes in patterns of neural activity or sensory experience. Plasticity of cortical excitatory synapses is thought to be important for learning and memory, leading to alterations in sensory representations and cognitive maps. However, these changes must be coordinated across other synapses within local circuits to preserve neural coding schemes and the organization of excitatory and inhibitory inputs, i.e., excitatory-inhibitory balance. Recent studies indicate that inhibitory synapses are also plastic and are controlled directly by a large number of neuromodulators, particularly during episodes of learning. Many modulators transiently alter excitatory-inhibitory balance by decreasing inhibition, and thus disinhibition has emerged as a major mechanism by which neuromodulation might enable long-term synaptic modifications naturally. This review examines the relationships between neuromodulation and synaptic plasticity, focusing on the induction of long-term changes that collectively enhance cortical excitatory-inhibitory balance for improving perception and behavior.

  9. Environmental evaluation of plastic waste management scenarios

    DEFF Research Database (Denmark)

    Rigamonti, L.; Grosso, M.; Møller, Jacob

    2014-01-01

    The management of the plastic fraction is one of the most debated issues in the discussion on integrated municipal solid waste systems. Both material and energy recovery can be performed on such a waste stream, and different separate collection schemes can be implemented. The aim of the paper....... The study confirmed the difficulty to clearly identify an optimal strategy for plastic waste management. In fact none of the examined scenarios emerged univocally as the best option for all impact categories. When moving from the P0 treatment strategy to the other scenarios, substantial improvements can...... is to contribute to the debate, based on the analysis of different plastic waste recovery routes. Five scenarios were defined and modelled with a life cycle assessment approach using the EASEWASTE model. In the baseline scenario (P0) the plastic is treated as residual waste and routed partly to incineration...

  10. Sol-gel antireflective coating on plastics

    Science.gov (United States)

    Ashley, Carol S.; Reed, Scott T.

    1990-01-01

    An antireflection film made from a reliquified sol-gel hydrolyzation, condensation polymeric reaction product of a silicon, alkoxides and/or metal alkoxides, or mixtures thereof. The film is particularly useful for coating plastics.

  11. Construction loads experienced by plastic composite ties.

    Science.gov (United States)

    2014-07-01

    Damage to plastic composite ties during handling and track installation has been reported by a number of railroads. Results from : a survey conducted to identify specific handling issues were used to develop field and laboratory tests to measure the ...

  12. Leaching behavior of solidified plastics radioactive wastes

    International Nuclear Information System (INIS)

    Yook, Chong Chul; Lee, Byung Hun; Jae, Won Mok; Kim, Kyung Eung

    1986-01-01

    It is highly needed to develope the solidification process to dispose safely the radioactive wastes increasing with the growth of the nuclear industry. The leaching mechanisms of the solidified plastic wastes were investigated and the leaching rates of the plastic wastes were also measured among the many solidification processes. In addition, the transport equation based on the diffusion or the diffusion-dissolution was compared with the empirical equation derived from the experimental data by graphical method. Consequently, leaching process of the solidified plastic wastes is quite well agreed with the mass transport theory, but it may be difficult to simulate leaching process by diffusion dissolution mechanism. But the theoretical equation could be applicable to the cumulative amount of radionuclides leached form the plastic wastes disposed into the environment. (Author)

  13. Core Characteristics Deterioration due to Plastic Deformation

    Science.gov (United States)

    Kaido, Chikara; Arai, Satoshi

    This paper discusses the effect of plastic deformation at core manufacturing on the characteristics of cores where non-oriented electrical steel sheets are used as core material. Exciting field and iron loss increase proportionally to plastic deformation in the case of rPeddy currents increase because plastic deformations of crystalline grains are distributed and then the flux distribution is induced. In the case of rP>20, the deterioration tend to saturate, and the increases in magnetic field and iron loss are 1000 to 1500A/m and 2 to 4W/kg. They are related to grain size, and high grade with larger grain may have lager field increase and smaller iron loss increase. Anomalous eddy current losses scarcely increase in this region. In actual motors, the plastic deformation affects iron loss increase although exciting current increases a little.

  14. Pathological Plasticity in Fragile X Syndrome

    Directory of Open Access Journals (Sweden)

    Brandon S. Martin

    2012-01-01

    Full Text Available Deficits in neuronal plasticity are common hallmarks of many neurodevelopmental disorders. In the case of fragile-X syndrome (FXS, disruption in the function of a single gene, FMR1, results in a variety of neurological consequences directly related to problems with the development, maintenance, and capacity of plastic neuronal networks. In this paper, we discuss current research illustrating the mechanisms underlying plasticity deficits in FXS. These processes include synaptic, cell intrinsic, and homeostatic mechanisms both dependent on and independent of abnormal metabotropic glutamate receptor transmission. We place particular emphasis on how identified deficits may play a role in developmental critical periods to produce neuronal networks with permanently decreased capacity to dynamically respond to changes in activity central to learning, memory, and cognition in patients with FXS. Characterizing early developmental deficits in plasticity is fundamental to develop therapies that not only treat symptoms but also minimize the developmental pathology of the disease.

  15. Plastic debris in the open ocean

    OpenAIRE

    Cózar, Andrés; Echevarría, Fidel; González-Gordillo, J. Ignacio; Irigoien, Xabier; Úbeda, Bárbara; Hernández-León, Santiago; Palma, Álvaro T.; Navarro, Sandra; García-de-Lomas, Juan; Ruiz, Andrea; Fernández-de-Puelles, María L.; Duarte, Carlos M.

    2014-01-01

    There is a rising concern regarding the accumulation of floating plastic debris in the open ocean. However, the magnitude and the fate of this pollution are still open questions. Using data from the Malaspina 2010 circumnavigation, regional surveys, and previously published reports, we show a worldwide distribution of plastic on the surface of the open ocean, mostly accumulating in the convergence zones of each of the five subtropical gyres with comparable density. Howeve...

  16. Development of a Plastic Recycling Machine

    OpenAIRE

    I. A. Daniyan,

    2017-01-01

    Plastics are not degradable materials, therefore improper disposal after use constitute environmental problem. The developed plastic recycler was fabricated using 1.5 mm mild metal sheet punched and rolled into cylindrical form. The outer peeling drum was punched inward and fixed to the machine frame while the inner peeling drum was punched outward. The inner drum was constructed using 1.5 mm galvanized metal sheet while the die was constructed using carbon steel. It has an outer diameter of ...

  17. Molding apparatus. [for thermosetting plastic compositions

    Science.gov (United States)

    Heier, W. C. (Inventor)

    1974-01-01

    Apparatus for compression molding of thermosetting plastics compositions including interfitting hollow male and female components is reported. The components are adapted to be compressed to form a rocket nozzle in a cavity. A thermal jacket is provided exteriorly adjacent to the female component for circulating a thermal transfer fluid to effect curing of a thermosetting plastics material being molded. Each of the male and female components is provided with suitable inlets and outlets for circulating a thermal transfer fluid.

  18. Laser direct joining of metal and plastic

    International Nuclear Information System (INIS)

    Katayama, Seiji; Kawahito, Yousuke

    2008-01-01

    We have developed an innovative rapid laser direct joining process of metal and plastic lap plates without adhesives or glues. The joints made between a Type 304 stainless steel plate and a polyethylene terephthalate (PET) plastic sheet of 30 mm width possessed tensile shear loads of about 3000 N. Transmission electron microscope photographs of the joint demonstrated that Type 304 and the PET were bonded on the atomic, molecular or nanostructural level through a Cr oxide film

  19. Plastic for indicating a radiation dose

    International Nuclear Information System (INIS)

    Hori, Y.; Yoshikawa, N.; Ohmori, S.

    1975-01-01

    A plastic film suitable for indicating radiation dose contains a chlorine polymer, at least one acid sensitive coloring agent and a plasticizer. The film undergoes a distinct change of color in response to a given radiation dose, the degree of change proportional to the total change. These films may be stored for a long period without loss of sensitivity, and have good color stability after irradiation. (auth)

  20. Banana peels based bio-plastic

    OpenAIRE

    Taodharos, Shady

    2018-01-01

    Every developed country depends on the industry as the main factor of its economy. Lack of exports, depression in both the general economy and the value of the currency are consequences of neglecting the industry. All countries work on increasing the efficiency of their industries by whether working on the input, the output, the cost or the time of the process. Plastic industry is considered one of the most important industries because plastic is an important factor in the making of many usef...

  1. 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...

  2. Plastic bowing of the ribs in children

    Energy Technology Data Exchange (ETDEWEB)

    Caro, P.A.; Borden, S. IV

    1988-06-01

    Four cases of plastic bowing of the ribs are presented. In three patients with Werdnig-Hoffman disease, plastic curvatures were associated with chronic pneumonia and atelectasis. We postulate that intrapulmonary retractive forces can deform ribs thinned by muscular atrophy. In turn, thoracic collapse can perpetuate lobar and segmental atelectasis. In one case of osteogenesis imperfecta without pneumonia, we believe normal muscle forces bent ribs weakened by deficiency of normal cortical architecture.

  3. Plastic bowing of the ribs in children

    International Nuclear Information System (INIS)

    Caro, P.A.; Borden, S. IV

    1988-01-01

    Four cases of plastic bowing of the ribs are presented. In three patients with Werdnig-Hoffman disease, plastic curvatures were associated with chronic pneumonia and atelectasis. We postulate that intrapulmonary retractive forces can deform ribs thinned by muscular atrophy. In turn, thoracic collapse can perpetuate lobar and segmental atelectasis. In one case of osteogenesis imperfecta without pneumonia, we believe normal muscle forces bent ribs weakened by deficiency of normal cortical architecture. (orig.)

  4. Treatment of contaminated waste plastics material

    International Nuclear Information System (INIS)

    Sims, J.; Hitchcock, J.W.

    1984-01-01

    Radioactive contaminated plastics material is treated by reducing it to uniform-sized debris and extruding it from a heated extruder into a sealed container in monolithic block form or as an in-fill matrix for other contaminated waste articles to create a substantially void-free sealed mass for disposal. Density adjusting fillers may be included. Extrusion may alternatively take place into a clean sealable plastics tube. (author)

  5. Soil plasticity with a different porosity

    Directory of Open Access Journals (Sweden)

    Klovanych Sergii

    2017-01-01

    Full Text Available The model of soils with different porosity in the framework of the associated theory of plasticity is presented The single analytical function describes the loading surface in the stress space. The deformational hardening/softening and the phenomenon of dilatancy during plastic flow are incorporated in the model. The triaxial compression tests are simulated and compared with the experimental results for different values of the void ratio and initial hydrostatic stresses.

  6. Plastic, Fantastic? What We Make. Science and Technology Education in Philippine Society.

    Science.gov (United States)

    Philippines Univ., Quezon City. Inst. for Science and Mathematics Education Development.

    This module provides information about plastics, focusing on the uses of plastic bags in particular. Topic areas considered include: (1) making plastic bags; (2) transparency of plastic bags; (3) plastic bags and food odors; (4) food containers (before and since plastics); and (5) disposing of plastic bags and other plastic products. The text is…

  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. 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)

  9. 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 .

  10. Changing trends in plastic surgery training

    Directory of Open Access Journals (Sweden)

    Ramesh Kumar Sharma

    2014-01-01

    Full Text Available Background: The currently available training models are being put to scrutiny in India today, both by the residents and the teachers. Plastic surgery specialty was created primarily for reconstructive purposes but the society always perceived it from a cosmetic angle, particularly in the post second world war era. As a result, there is a need to redefine the goals of plastic surgery training in the present times so that the plastic surgeon is "future ready" to meet the needs of society and the market forces. Materials and Methods: The author has reviewed the currently available literature on plastic surgery training from India and the western countries. An attempt has been made to study opinions from the teachers and the trainees. The modules currently available in India and abroad have been analyzed and a suggestion has been made for drafting training programs that would meet the demands of the society as well as prepare the resident both for the aesthetic and reconstructive practice. Conclusions: The plastic surgery training needs to be more vibrant and in tune with the changing times. While maintaining its core nature, the current predominantly reconstructive modules need to incorporate the aesthetic content. The evaluation should be both knowledge and competence based. The teachers need to be educated in the various teaching methods that are more applicable to grown up residents. There is a need to find ways to attract talented people in the academic plastic surgery.

  11. Changing trends in plastic surgery training.

    Science.gov (United States)

    Sharma, Ramesh Kumar

    2014-05-01

    The currently available training models are being put to scrutiny in India today, both by the residents and the teachers. Plastic surgery specialty was created primarily for reconstructive purposes but the society always perceived it from a cosmetic angle, particularly in the post second world war era. As a result, there is a need to redefine the goals of plastic surgery training in the present times so that the plastic surgeon is "future ready" to meet the needs of society and the market forces. The author has reviewed the currently available literature on plastic surgery training from India and the western countries. An attempt has been made to study opinions from the teachers and the trainees. The modules currently available in India and abroad have been analyzed and a suggestion has been made for drafting training programs that would meet the demands of the society as well as prepare the resident both for the aesthetic and reconstructive practice. The plastic surgery training needs to be more vibrant and in tune with the changing times. While maintaining its core nature, the current predominantly reconstructive modules need to incorporate the aesthetic content. The evaluation should be both knowledge and competence based. The teachers need to be educated in the various teaching methods that are more applicable to grown up residents. There is a need to find ways to attract talented people in the academic plastic surgery.

  12. Fifty Years of Innovation in Plastic Surgery

    Directory of Open Access Journals (Sweden)

    Richard M Kwasnicki

    2016-03-01

    Full Text Available BackgroundInnovation has molded the current landscape of plastic surgery. However, documentation of this process only exists scattered throughout the literature as individual articles. The few attempts made to profile innovation in plastic surgery have been narrative, and therefore qualitative and inherently biased. Through the implementation of a novel innovation metric, this work aims to identify and characterise the most prevalent innovations in plastic surgery over the last 50 years.MethodsPatents and publications related to plastic surgery (1960 to 2010 were retrieved from patent and MEDLINE databases, respectively. The most active patent codes were identified and grouped into technology areas, which were subsequently plotted graphically against publication data. Expert-derived technologies outside of the top performing patents areas were additionally explored.ResultsBetween 1960 and 2010, 4,651 patents and 43,118 publications related to plastic surgery were identified. The most active patent codes were grouped under reconstructive prostheses, implants, instruments, non-invasive techniques, and tissue engineering. Of these areas and other expert-derived technologies, those currently undergoing growth include surgical instruments, implants, non-invasive practices, transplantation and breast surgery. Innovations related to microvascular surgery, liposuction, tissue engineering, lasers and prostheses have all plateaued.ConclusionsThe application of a novel metric for evaluating innovation quantitatively outlines the natural history of technologies fundamental to the evolution of plastic surgery. Analysis of current innovation trends provides some insight into which technology domains are the most active.

  13. Plastic photochromic eyewear: a status report

    Science.gov (United States)

    Crano, John C.; Elias, Richard C.

    1991-12-01

    An estimated 10 million pairs of photochromic prescription lenses were dispensed in the United States in 1989, essentially all based on a silver halide system suspended in an inorganic glass. A significant trend within the ophthalmic industry has been the growth of light-weight plastic lenses. In the United States market, the percentage of prescription eyewear made of plastic is now greater than 70%. With this increasing market penetration of plastic lenses, the desire for an acceptable plastic photochromic lens has also increased. As with any commercial product, in order to achieve consumer acceptance there exist several technical requirements for a plastic photochromic lens. These include the light transmission and color of the lens in both the unactivated and activated states, the speeds of darkening and fading, and the fatigue resistance or lifetime of the photochromic system. These requirements will be defined along with approaches to achieving them. The properties of the commercially available plastic photochromic lenses will be compared with the defined requirements.

  14. Discoloration of plasticized PVC upon irradiation

    International Nuclear Information System (INIS)

    Kojima, Keiichi; Ueno, Keiji; Kumafuji, Hisao.

    1981-01-01

    The effects of the factors on the discoloration of PVC cross-linked by electron irradiation, such as irradiation dose, the polymerization degree of PVC resin, plasticizers and stabilizers, were studied. The composition of the plasticized PVC used for the experiment was 100 PHR of PVC, 50 PHR of plasticizer, 5 PHR of stabilizer and 5 PHR of cross-linking agent (TMPMA). Three samples with the different degree of polymerization of the PVC resin were used, namely 750, 1050 and 2600. As the plasticizers, phthalic acid esters (DBP, DOP, DIDP), trimellitic acid esters (TOTM, n-TOTM), fatty acid esters (DOS, DOZ), polyester and epoxy group plasticizers were used. The irradiation dose for the test was 3, 6 and 12 Mrad. The experimental results are summarized as follows. As the electron irradiation dose was higher, the resultant discoloration was more remarkable, and the optimum irradiation dose was below 6 Mrad. The degree of polymerization of the PVC resin did not affect the irradiation discoloration. However it was noticed that the cross-linking efficiency was better as the degree of polymerization was higher. The cross-linking efficiency was better as the content of plasticizer was more. The fatty acid esters and epoxy groups showed less discoloration and better cross-linking efficiency. Tin and barium-zinc stabilizers were good. (Kako, I.)

  15. 49 CFR 192.193 - Valve installation in plastic pipe.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 3 2010-10-01 2010-10-01 false Valve installation in plastic pipe. 192.193... Components § 192.193 Valve installation in plastic pipe. Each valve installed in plastic pipe must be designed so as to protect the plastic material against excessive torsional or shearing loads when the valve...

  16. 49 CFR 178.517 - Standards for plastic boxes.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 2 2010-10-01 2010-10-01 false Standards for plastic boxes. 178.517 Section 178... PACKAGINGS Non-bulk Performance-Oriented Packaging Standards § 178.517 Standards for plastic boxes. (a) The following are identification codes for plastic boxes: (1) 4H1 for an expanded plastic box; and (2) 4H2 for a...

  17. 49 CFR 192.321 - Installation of plastic pipe.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 3 2010-10-01 2010-10-01 false Installation of plastic pipe. 192.321 Section 192... Transmission Lines and Mains § 192.321 Installation of plastic pipe. (a) Plastic pipe must be installed below ground level except as provided by paragraphs (g) and (h) of this section. (b) Plastic pipe that is...

  18. 49 CFR 178.519 - Standards for plastic film bags.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 2 2010-10-01 2010-10-01 false Standards for plastic film bags. 178.519 Section... PACKAGINGS Non-bulk Performance-Oriented Packaging Standards § 178.519 Standards for plastic film bags. (a) The identification code for a plastic film bag is 5H4. (b) Construction requirements for plastic film...

  19. 33 CFR 183.552 - Plastic encased fuel tanks: Installation.

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Plastic encased fuel tanks... § 183.552 Plastic encased fuel tanks: Installation. (a) Each fuel tank encased in cellular plastic foam or in fiber reinforced plastic must have the connections, fittings, and labels accessible for...

  20. DMPD: Developmental plasticity of lymphocytes. [Dynamic Macrophage Pathway CSML Database

    Lifescience Database Archive (English)

    Full Text Available 18472258 Developmental plasticity of lymphocytes. Cobaleda C, Busslinger M. Curr Op...in Immunol. 2008 Apr;20(2):139-48. Epub 2008 May 9. (.png) (.svg) (.html) (.csml) Show Developmental plastic...ity of lymphocytes. PubmedID 18472258 Title Developmental plasticity of lymphocytes. Authors Cobaleda C, Bus

  1. 49 CFR 192.375 - Service lines: Plastic.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 3 2010-10-01 2010-10-01 false Service lines: Plastic. 192.375 Section 192.375... § 192.375 Service lines: Plastic. (a) Each plastic service line outside a building must be installed... terminate above ground level and outside the building, if— (i) The above ground level part of the plastic...

  2. 49 CFR 192.191 - Design pressure of plastic fittings.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 3 2010-10-01 2010-10-01 false Design pressure of plastic fittings. 192.191... Components § 192.191 Design pressure of plastic fittings. (a) Thermosetting fittings for plastic pipe must conform to ASTM D 2517, (incorporated by reference, see § 192.7). (b) Thermoplastic fittings for plastic...

  3. Consumer Exposure to Bisphenol A from Plastic Bottles

    Science.gov (United States)

    Bidabadi, Fatemeh

    2013-01-01

    Bisphenol A (BPA) is a plastic monomer and plasticizer and is a chemical that has one of the highest volume production worldwide, with more than six billion pounds each year. Its primary use is the production of polycarbonate plastics, epoxy resins used to line metal cans in a host of plastic consumer products such as toys, water pipes, drinking…

  4. 21 CFR 872.5470 - Orthodontic plastic bracket.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Orthodontic plastic bracket. 872.5470 Section 872...) MEDICAL DEVICES DENTAL DEVICES Therapeutic Devices § 872.5470 Orthodontic plastic bracket. (a) Identification. An orthodontic plastic bracket is a plastic device intended to be bonded to a tooth to apply...

  5. Scenarios study on post-consumer plastic packaging waste recycling

    NARCIS (Netherlands)

    Thoden van Velzen, E.U.; Bos-Brouwers, H.E.J.; Groot, J.J.; Bing Xiaoyun, Xiaoyun; Jansen, M.; Luijsterburg, B.

    2013-01-01

    We all use plastics on a daily basis. Plastics come in many shapes, sizes and compositions and are used in a wide variety of products. Almost all of the currently used plastic packaging are made from fossil resources, which are finite. The production of plastic packages causes environmental impacts,

  6. Plasticity: A New Materialist Approach to Policy and Methodology

    Science.gov (United States)

    Ulmer, Jasmine B.

    2015-01-01

    This article examines Catherine Malabou's philosophical concept of plasticity as a new materialist methodology. Given that plasticity simultaneously maintains the ability to receive, give, and annihilate form, plasticity and plastic readings offer material-discursive possibilities for educational research. This article begins by discussing the…

  7. Finite element analysis of a finite-strain plasticity problem

    International Nuclear Information System (INIS)

    Crose, J.G.; Fong, H.H.

    1984-01-01

    A finite-strain plasticity analysis was performed of an engraving process in a plastic rotating band during the firing of a gun projectile. The aim was to verify a nonlinear feature of the NIFDI/RB code: plastic large deformation analysis of nearly incompressible materials using a deformation theory of plasticity approach and a total Lagrangian scheme. (orig.)

  8. 21 CFR 878.3925 - Plastic surgery kit and accessories.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Plastic surgery kit and accessories. 878.3925... (CONTINUED) MEDICAL DEVICES GENERAL AND PLASTIC SURGERY DEVICES Prosthetic Devices § 878.3925 Plastic surgery kit and accessories. (a) Identification. A plastic surgery kit and accessories is a device intended to...

  9. Chemical constituent influence on ionizing radiation treatment of a wood–plastic composite

    International Nuclear Information System (INIS)

    Palm, Andrew; Smith, Jennifer; Driscoll, Mark; Smith, Leonard; Scott Larsen, L.

    2016-01-01

    A dose range of 0–200 kGy was used to irradiate polyethylene-based wood plastic composite (WPC) specimens. An evaluation of mechanical properties in bending resulted in an increase in ultimate strength, but little effect to stiffness. The bending test results were compared to previous testing in order to examine reproducibility. Hardness tests were also conducted, revealing an increase at a dose range of 0–250 kGy. - Highlights: • Feasibility of electron beam treatment of a wood plastic composite. • No significant impact on modulus of elasticity. • Increase in ultimate strength and hardness.

  10. Strain gradient plasticity modeling of hydrogen diffusion to the crack tip

    DEFF Research Database (Denmark)

    Martínez Pañeda, Emilio; del Busto, S.; Niordson, Christian Frithiof

    2016-01-01

    to characterize the gradient-enhanced stress elevation and subsequent diffusion of hydrogen towards the crack tip. Results reveal that GNDs, absent in conventional plasticity predictions, play a fundamental role on hydrogen transport ahead of a crack. SGP estimations provide a good agreement with experimental......In this work hydrogen diffusion towards the fracture process zone is examined accounting for local hardening due to geometrically necessary dislocations (GNDs) by means of strain gradient plasticity (SGP). Finite element computations are performed within the finite deformation theory...

  11. 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.

  12. 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%.

  13. Dictionary of plastics. 7. rev. ed. Kunststoff-Lexikon

    Energy Technology Data Exchange (ETDEWEB)

    Stoeckhert, K [ed.

    1981-01-01

    The book starts with a list of about 400 acronyms for plastic materials and additives, caoutchouc types, and synthetic fibers. This is followed by a 500-page glossary of plastics and a 200-page appendix listing producers of plastic feedstocks, chemical substances and additives, recoverable materials, processing systems, semi-finished plastic products and end products, machinery, tools and further aids for plastics processing. (HK).

  14. Monitoring the abundance of plastic debris in the marine environment

    OpenAIRE

    Ryan, Peter G.; Moore, Charles J.; van Franeker, Jan A.; Moloney, Coleen L.

    2009-01-01

    Plastic debris has significant environmental and economic impacts in marine systems. Monitoring is crucial to assess the efficacy of measures implemented to reduce the abundance of plastic debris, but it is complicated by large spatial and temporal heterogeneity in the amounts of plastic debris and by our limited understanding of the pathways followed by plastic debris and its long-term fate. To date, most monitoring has focused on beach surveys of stranded plastics and other litter. Infreque...

  15. Behavioral Response to Plastic Bag Legislation in Botswana

    OpenAIRE

    Dikgang, Johane; Visser, Martine

    2010-01-01

    This paper investigates the use of charges and standards in dealing with a common externality, plastic litter from shopping bags in Botswana. The country passed a plastic bag tax (effective 2007) to curb the plastic bag demand. Interestingly, the legislation did not force retailers to charge for plastic bags, which they did voluntarily at different prices. We assessed the environmental effectiveness and efficiency of the plastic bag legislation by analyzing consumers’ sensitivity to the impro...

  16. Are consumers concerned about plastic water bottles environmental impact?

    OpenAIRE

    Caroline Orset; Nicolas Barret; Aurélien Lemaire

    2015-01-01

    Although plastic induces environmental damages, almost all water bottles are made from plastic. However, these damages are more or less significant according to the plastic used. This study evaluates the consumers' willingness to pay (WTP) for different plastics used for water packaging. Successive messages emphasizing the characteristics of plastic are delivered to participants allowing explaining information influence on the consumers' WTP. We find that information has a significant effect ...

  17. Contaminants in northern fulmars (Fulmarus glacialis) exposed to plastic

    OpenAIRE

    Ask, Amalie V.; Anker-Nilssen, Tycho; Herzke, Dorte; Trevail, Alice; Franeker, Jan Andries van; Gabrielsen, Geir Wing

    2016-01-01

    Northern fulmars are seabirds which feed exclusively at sea, and as such, they are useful indicators of ocean health. Marine plastic pollution is an ever-increasing and global issue that affects the northern fulmar as they are frequently found to have ingested plastic. In this report we investigate whether the amount of ingested plastic affects the concentration of certain plastic-adsorbed toxicants in their tissues. Marine plastic pollution is a field of utmost importance. It is our hope tha...

  18. Epigenetic control of cell identity and plasticity

    KAUST Repository

    Orlando, Valerio

    2014-04-02

    The DNA centered dogma for genetic information and cell identity is now evolving into a much more complex and flexible dimension provided by the discovery of the Epigenome. This comprises those chromosome structural and topological components that complement DNA information and contribute to genome functional organization. Current concept is that the Epigenome constitutes the dynamic molecular interface allowing the Genome to interact with the Environment. Exploring how the genome interacts with the environment is a key to fully understand cellular and complex organism mechanisms of adaptation and plasticity. Our work focuses on the role of an essential, specialized group or chromatin associated proteins named Polycomb (PcG) that control maintenance of transcription programs during development and in adult life. In particular PcG proteins exert epigenetic “memory” function by modifying chromosome structures at various levels to maintain gene silencing in particular through cell division. While in the past decade substantial progress was made in understanding PcG mechanisms acting in development and partially during cell cycle, very little is known about their role in adult post-mitotic tissues and more in general the role of the epigenome in adaptation. To this, we studied the role of PcG in the context of mammalian skeletal muscle cell differentiation. We previously reported specific dynamics of PRC2 proteins in myoblasts and myotubes, in particular the dynamics of PcG Histone H3 K27 Methyl Transferases (HMT), EZH2 and EZH1, the latter apparently replacing for EZH2 in differentiated myotubes. Ezh1 protein, although almost identical to Ezh2, shows a weak H3K27 HMT activity and its primary function remains elusive. Recent ChIPseq studies performed in differentiating muscle cells revealed that Ezh1 associates with active and not repressed regulatory regions to control RNA pol II elongation. Since H3K27 tri-methylation levels are virtually steady in non

  19. Recent advancements and prospects of plastic surgery

    Directory of Open Access Journals (Sweden)

    Xin XING

    2011-09-01

    Full Text Available Objective To summarize the recent advancements and developmental prospects of plastic surgery worldwide,and to describe the future directions,aims,and highlights of Chinese military plastic surgery.Methods Relevant articles published in the last five years were retrieved through a search in PubMed,Medline,and CMCC.A statistical survey was conducted to summarize the achievements obtained by the Chinese military plastic surgery unit in the last five years.Results Considerable progress has been achieved in both clinical treatment and basic research of plastic surgery in the past five years.Its important role in the early treatment of combat injury and trauma has been recognized and emphasized.Chinese military plastic surgery has achieved considerable accomplishments in the last five years,especially in chronic wound repair;mechanism,prevention,and treatment of explosive soft tissue injuries and seawater immersion wounds;and new remedies of maxillofacial traumatic deformity,composite facial tissue allograft,and so on.Conclusions The repair and reconstruction of tissue defect and deformity caused by war injury and trauma will be the future major research direction of military plastic surgery.Research work should focus on tissue engineering,composite tissue allograft,stem cell therapy,mechanism of abnormal scar formation,among others,to solve the clinical problems of destructive facial injuries,extensive thora-abdominal wall defects,chronic ulcer,abnormal scars,and so on.Furthermore,plastic surgeons should fully utilize their special skills and take active part in the early treatment of war injury and trauma.

  20. Social Media and the Plastic Surgery Patient.

    Science.gov (United States)

    Sorice, Sarah C; Li, Alexander Y; Gilstrap, Jarom; Canales, Francisco L; Furnas, Heather J

    2017-11-01

    Many plastic surgeons use social media as a marketing tool to attract and retain patients, but information about how patients use social media and their preferred types of plastic surgery posts have been lacking. To investigate patients' preferred social media networks and the type of posts they wished to see, a cross-sectional study was conducted in a single aesthetic practice of two plastic surgeons by surveying 100 consecutive patients. The age of the patients averaged 44.4 years (range, 17 to 78 years). Facebook had the greatest patient use and engagement, with YouTube second in use, and Instagram second in number of engaged users. Over half used Pinterest, but with little daily engagement. Only one-fourth used Snapchat, but the percentage of users who were highly engaged was second only to Facebook. The least popular network was Twitter, with the fewest patient users and least engagement. Social media played a minor role compared with the practice's Web site in both influencing patients to choose the practice and providing information on the day of the appointment. Patients most wanted to see posts on a plastic surgeon's social media platform related to practice information, before-and-after photographs, and contests. Articles about plastic surgery held the least interest. Among five types of Web site content, patients expressed most interest in before-and-after photographs. This study is the first to articulate the plastic surgery patient perspective regarding social media. The findings aim to help plastic surgeons maximize their influence on their target audience.

  1. [The role of balneology in plastic surgery].

    Science.gov (United States)

    Correia, N; Binet, A; Caliot, J; Poli Merol, M-L; Bodin, F; François-Fiquet, C

    2016-02-01

    Balneology can be part of the plastic surgery care sector. The objectives of this study were firstly to the state of knowledge about the hydrotherapy and specify the place reserved for hydrotherapy by surgeons as an adjunct in plastic and reconstructive surgery (adult and child). Multicentric national study by poll (Google Drive®) focused at plastic and/or pediatric surgeons. The following information was analyzed: frequency, timing of prescription, indications, the surgeon's feelings towards hydrotherapy and the differences between adult's and children's prescriptions. Fifty-four teams were contacted: 22 responses were received (15 "adult" plastic surgeons, 9 "pediatric" plastic surgeons, 6 pediatric surgeons, with 12 out of 22 working with burnt patients). Eighteen out of 22 prescribed hydrotherapy. Twenty out of 22 thought that hydrotherapy had a role as adjuvant therapy in plastic surgery. The indications were: burns (11/20), skin-graft hypertrophy (10/20), inflammatory and pruritic scar and cutaneous trophic disorders (9/20), psychological (3/20), retractions (2/20), weight loss and smoking (1/20). The timing of the prescription was: 6 months and 1 year (8/20) after surgery/trauma. Twenty out of 22 found a beneficial effect: physical (19/20): reduction of inflammatory signs, pruritus and pain, scar maturation, skin thinning improvement; psychological (14/20): positive for patient/family. Five out of 17 made the difference between child/adult, 10/17 made no difference but only treated adults or children. The respondents in the study are probably more sensitive to the effects of hydrotherapy that non-respondents. It is difficult to assess the real impact of hydrotherapy in plastic surgery because distinguishing spontaneous favorable evolution of a scar from one only due to the hydrotherapy or multidisciplinary management is difficult. However, hydrotherapy seems to have its role among multidisciplinary management. Copyright © 2015 Elsevier Masson SAS. All

  2. The plastic rotation effect in an isotropic gradient plasticity model for applications at the meso scale

    NARCIS (Netherlands)

    Poh, Leong Hien; Peerlings, R.H.J.

    2016-01-01

    Although formulated to represent a large system of polycrystals at the macroscopic level, isotropic gradient plasticity models have routinely been adopted at the meso scale. For such purposes, it is crucial to incorporate the plastic rotation effect in order to obtain a reasonable approximation of

  3. Preparing Attitude Scale to Define Students' Attitudes about Environment, Recycling, Plastic and Plastic Waste

    Science.gov (United States)

    Avan, Cagri; Aydinli, Bahattin; Bakar, Fatma; Alboga, Yunus

    2011-01-01

    The aim of this study is to introduce an attitude scale in order to define students? attitudes about environment, recycling, plastics, plastic waste. In this study, 80 attitude sentences according to 5-point Likert-type scale were prepared and applied to 492 students of 6th grade in the Kastamonu city center of Turkey. The scale consists of…

  4. 75 FR 34170 - Plastic Omnium Automotive Exteriors, LLC, Anderson, SC; Plastic Omnium Automotive Exteriors, LLC...

    Science.gov (United States)

    2010-06-16

    ... Omnium Automotive Exteriors, LLC, Anderson, SC; Plastic Omnium Automotive Exteriors, LLC, Troy, MI... the Anderson, South Carolina location of Plastic Omnium Automotive Exteriors, LLC, working out of Troy... certification to include workers in support of the Anderson, South Carolina facility working out of Troy...

  5. 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.

  6. Managing plastic waste in East Africa: Niche innovations in plastic production and solid waste

    NARCIS (Netherlands)

    Ombis, L.O.; Vliet, van B.J.M.; Mol, A.P.J.

    2015-01-01

    This paper assesses the uptake of environmental innovation practices to cope with plastic waste in Kenyan urban centres at the interface of solid waste management and plastic production systems. The Multi Level Perspective on Technological Transitions is used to evaluate 7 innovation pathways of

  7. Degradation of oxo-biodegradable plastic by Pleurotus ostreatus.

    Science.gov (United States)

    da Luz, José Maria Rodrigues; Paes, Sirlaine Albino; Nunes, Mateus Dias; da Silva, Marliane de Cássia Soares; Kasuya, Maria Catarina Megumi

    2013-01-01

    Growing concerns regarding the impact of the accumulation of plastic waste over several decades on the environmental have led to the development of biodegradable plastic. These plastics can be degraded by microorganisms and absorbed by the environment and are therefore gaining public support as a possible alternative to petroleum-derived plastics. Among the developed biodegradable plastics, oxo-biodegradable polymers have been used to produce plastic bags. Exposure of this waste plastic to ultraviolet light (UV) or heat can lead to breakage of the polymer chains in the plastic, and the resulting compounds are easily degraded by microorganisms. However, few studies have characterized the microbial degradation of oxo-biodegradable plastics. In this study, we tested the capability of Pleurotus ostreatus to degrade oxo-biodegradable (D2W) plastic without prior physical treatment, such as exposure to UV or thermal heating. After 45 d of incubation in substrate-containing plastic bags, the oxo-biodegradable plastic, which is commonly used in supermarkets, developed cracks and small holes in the plastic surface as a result of the formation of hydroxyl groups and carbon-oxygen bonds. These alterations may be due to laccase activity. Furthermore, we observed the degradation of the dye found in these bags as well as mushroom formation. Thus, P. ostreatus degrades oxo-biodegradable plastics and produces mushrooms using this plastic as substrate.

  8. Degradation of oxo-biodegradable plastic by Pleurotus ostreatus.

    Directory of Open Access Journals (Sweden)

    José Maria Rodrigues da Luz

    Full Text Available Growing concerns regarding the impact of the accumulation of plastic waste over several decades on the environmental have led to the development of biodegradable plastic. These plastics can be degraded by microorganisms and absorbed by the environment and are therefore gaining public support as a possible alternative to petroleum-derived plastics. Among the developed biodegradable plastics, oxo-biodegradable polymers have been used to produce plastic bags. Exposure of this waste plastic to ultraviolet light (UV or heat can lead to breakage of the polymer chains in the plastic, and the resulting compounds are easily degraded by microorganisms. However, few studies have characterized the microbial degradation of oxo-biodegradable plastics. In this study, we tested the capability of Pleurotus ostreatus to degrade oxo-biodegradable (D2W plastic without prior physical treatment, such as exposure to UV or thermal heating. After 45 d of incubation in substrate-containing plastic bags, the oxo-biodegradable plastic, which is commonly used in supermarkets, developed cracks and small holes in the plastic surface as a result of the formation of hydroxyl groups and carbon-oxygen bonds. These alterations may be due to laccase activity. Furthermore, we observed the degradation of the dye found in these bags as well as mushroom formation. Thus, P. ostreatus degrades oxo-biodegradable plastics and produces mushrooms using this plastic as substrate.

  9. Degradation of plastic carrier bags in the marine environment

    International Nuclear Information System (INIS)

    O'Brine, Tim; Thompson, Richard C.

    2010-01-01

    Research highlights: → There is considerable concern about the hazards that plastic debris presents to wildlife. → Here we investigate breakdown of oxodegradable, compostable and conventional plastic bags. → Compostable plastic disappeared from our test rig between 16 and 24 weeks. → Approximately 98% of the other plastics remained after 40 weeks. → Fouling by marine organisms substantially reduced the amount of UV-light reaching the plastic. - Abstract: There is considerable concern about the hazards that plastic debris presents to wildlife. Use of polymers that degrade more quickly than conventional plastics presents a possible solution to this problem. Here we investigate breakdown of two oxo-biodegradable plastics, compostable plastic and standard polyethylene in the marine environment. Tensile strength of all materials decreased during exposure, but at different rates. Compostable plastic disappeared from our test rig between 16 and 24 weeks whereas approximately 98% of the other plastics remained after 40 weeks. Some plastics require UV light to degrade. Transmittance of UV through oxo-biodegradable and standard polyethylene decreased as a consequence of fouling such that these materials received ∼90% less UV light after 40 weeks. Our data indicate that compostable plastics may degrade relatively quickly compared to oxo-biodegradable and conventional plastics. While degradable polymers offer waste management solutions, there are limitations to their effectiveness in reducing hazards associated with plastic debris.

  10. Degradation of Oxo-Biodegradable Plastic by Pleurotus ostreatus

    Science.gov (United States)

    da Luz, José Maria Rodrigues; Paes, Sirlaine Albino; Nunes, Mateus Dias; da Silva, Marliane de Cássia Soares; Kasuya, Maria Catarina Megumi

    2013-01-01

    Growing concerns regarding the impact of the accumulation of plastic waste over several decades on the environmental have led to the development of biodegradable plastic. These plastics can be degraded by microorganisms and absorbed by the environment and are therefore gaining public support as a possible alternative to petroleum-derived plastics. Among the developed biodegradable plastics, oxo-biodegradable polymers have been used to produce plastic bags. Exposure of this waste plastic to ultraviolet light (UV) or heat can lead to breakage of the polymer chains in the plastic, and the resulting compounds are easily degraded by microorganisms. However, few studies have characterized the microbial degradation of oxo-biodegradable plastics. In this study, we tested the capability of Pleurotus ostreatus to degrade oxo-biodegradable (D2W) plastic without prior physical treatment, such as exposure to UV or thermal heating. After 45 d of incubation in substrate-containing plastic bags, the oxo-biodegradable plastic, which is commonly used in supermarkets, developed cracks and small holes in the plastic surface as a result of the formation of hydroxyl groups and carbon-oxygen bonds. These alterations may be due to laccase activity. Furthermore, we observed the degradation of the dye found in these bags as well as mushroom formation. Thus, P. ostreatus degrades oxo-biodegradable plastics and produces mushrooms using this plastic as substrate. PMID:23967057

  11. 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 pits develop into tree cracks in the initial stage of plastic zone development. Physical and mathematical model of crack and plastic zone is proposed; parameter of development free path of plastic zone is presented. Based on integration of elementary theories the stress analysis is build up; based on analyses of measured parameters, a set of common relations between parameters is obtained. Integrate parameter analysis and stress analysis, depth of plastic zone development, law and phenomenon in experimental data can be interpreted completely

  12. Plastic Surgery Response in Natural Disasters.

    Science.gov (United States)

    Chung, Susan; Zimmerman, Amanda; Gaviria, Andres; Dayicioglu, Deniz

    2015-06-01

    Disasters cause untold damage and are often unpredictable; however, with proper preparation, these events can be better managed. The initial response has the greatest impact on the overall success of the relief effort. A well-trained multidisciplinary network of providers is necessary to ensure coordinated care for the victims of these mass casualty disasters. As members of this network of providers, plastic surgeons have the ability to efficiently address injuries sustained in mass casualty disasters and are a valuable member of the relief effort. The skill set of plastic surgeons includes techniques that can address injuries sustained in large-scale emergencies, such as the management of soft-tissue injury, tissue viability, facial fractures, and extremity salvage. An approach to disaster relief, the types of disasters encountered, the management of injuries related to mass casualty disasters, the role of plastic surgeons in the relief effort, and resource management are discussed. In order to improve preparedness in future mass casualty disasters, plastic surgeons should receive training during residency regarding the utilization of plastic surgery knowledge in the disaster setting.

  13. Plasticity - a limiting case of creep

    International Nuclear Information System (INIS)

    Cords, H.; Kleist, G.; Zimmermann, R.

    1986-11-01

    The present work is an attempt to develop further the so-called unified theory for viscoplastic constitutive equations as used for metals or metal alloys. Typically, in similar approaches creep strains and plastic strains are derived from one common stress-strain relationship for inelastic strain rates employing an internal stress function as a back stress. Some novel concepts concerning the definition of the internal stress, plastic yielding and material hardening have been introduced, formulated mathematically and tested for correspondence with a standard type of materials behaviour. As a result of the investigations a system of simultaneous differential equations is defined which has been used to elaborate a common view on a number of different material effects observed in creep and plasticity i.e. normal and inverted primary creep, recoverable creep, incubation time and anelasticity in stress reduction, negative stress relaxation, plastic yielding, perfect plasticity, negative strain rate sensitivity, serrated flow, strain hardening in monotonic and cyclic loading. The theoretical approach is mainly based on a lateral contraction movement not following rigidly the longitudinal extension of the material specimen by a prescribed constant value of Poisson's ratio as usual, but following the axial extension in a process of drag which allows for retardation and which simultaneously impedes the longitudinal straining. (orig.) [de

  14. Neuron-glia metabolic coupling and plasticity.

    Science.gov (United States)

    Magistretti, Pierre J

    2006-06-01

    The coupling between synaptic activity and glucose utilization (neurometabolic coupling) is a central physiological principle of brain function that has provided the basis for 2-deoxyglucose-based functional imaging with positron emission tomography (PET). Astrocytes play a central role in neurometabolic coupling, and the basic mechanism involves glutamate-stimulated aerobic glycolysis; the sodium-coupled reuptake of glutamate by astrocytes and the ensuing activation of the Na-K-ATPase triggers glucose uptake and processing via glycolysis, resulting in the release of lactate from astrocytes. Lactate can then contribute to the activity-dependent fuelling of the neuronal energy demands associated with synaptic transmission. An operational model, the 'astrocyte-neuron lactate shuttle', is supported experimentally by a large body of evidence, which provides a molecular and cellular basis for interpreting data obtained from functional brain imaging studies. In addition, this neuron-glia metabolic coupling undergoes plastic adaptations in parallel with adaptive mechanisms that characterize synaptic plasticity. Thus, distinct subregions of the hippocampus are metabolically active at different time points during spatial learning tasks, suggesting that a type of metabolic plasticity, involving by definition neuron-glia coupling, occurs during learning. In addition, marked variations in the expression of genes involved in glial glycogen metabolism are observed during the sleep-wake cycle, with in particular a marked induction of expression of the gene encoding for protein targeting to glycogen (PTG) following sleep deprivation. These data suggest that glial metabolic plasticity is likely to be concomitant with synaptic plasticity.

  15. Radiation crosslinking of highly plasticized PVC

    Science.gov (United States)

    Mendizabal, E.; Cruz, L.; Jasso, C. F.; Burillo, G.; Dakin, V. I.

    1996-02-01

    To improve the physical properties of highly plasticized PVC, the polymer was crosslinked by gamma irradiation using a dose rate of 91 kGy/h. The effect of plasticizer type was studied by using three different plasticizers, 2,2,4-trimethyl-1,3-pentanediol diisobutyrate (TXIB), di(2-ethyl hexyl) phthalate (DOP), and di(2-ethylhexyl terephthalate) (DOTP), and varying irradiation doses. Gel content was determined by soxhlet extraction, tensile measurements were made on a universal testing machine and the mechano-dynamic measurements were made in a dynamic rheometer. It was found that a considerable bonding of plasticizer molecules to macromolelcules takes place along with crosslinking, so that the use of the solvent extraction method for measuring the degree of crosslinking can give erroneous information. Radiation-chemical crosslinking yield ( Gc) and molecular weight of interjunctions chains ( Mc), were calculated for different systems studied. Addition of ethylene glycol dimethacrylate (EGDM) as a crosslinking coagent and dioctyl tin oxide (DOTO) as a stabilizer was also studied. Plasticizers extraction resistance was increased by irradiation treatment.

  16. Radiation crosslinking of highly plasticized PVC

    International Nuclear Information System (INIS)

    Mendizabal, E.; Cruz, L.; Jasso, C.F.; Burillo, G.; Dakin, V.I.

    1996-01-01

    To improve the physical properties of highly plasticized PVC, the polymer was crosslinked by gamma irradiation using a dose rate of 91 kGy/h. The effect of plasticizer type was studied by using three different plasticizers, 2,2,4-trimethyl-1,3-pentanediol diisobutyrate (TXIB), di(2-ethyl hexyl) phthalate (DOP), and di(2-ethylhexyl terephthalate) (DOTP), and varying irradiation doses. Gel content was determined by soxhlet extraction, tensile measurements were made on a universal testing machine and the mechano-dynamic measurements were made in a dynamic rheometer. It was found that a considerable bonding of plasticizer molecules to macromolecules takes place along with crosslinking, so that the use of the solvent extraction method for measuring the degree of crosslinking can give erroneous information. Radiation-chemical crosslinking yield (G c ) and molecular weight of interjunctions chains (M c ), were calculated for different systems studied. Addition of ethylene glycol dimethyacrylate (EGDM) as a crosslinking coagent and dioctyl tin oxide (DOTO) as a stabilizer was also studied. Plasticizers extraction resistance was increased by irradiation treatment. (author)

  17. The neurophysiologist perspective into MS plasticity

    Directory of Open Access Journals (Sweden)

    Elise eHoudayer

    2015-09-01

    Full Text Available Multiple sclerosis (MS is a frequent, highly debilitating inflammatory demyelinating disease, starting to manifest in early adulthood and presenting a wide variety of symptoms which are often resistant to pharmacological treatments. Cortical dysfunctions have been demonstrated to be key components of MS condition, and plasticity of the corticospinal motor system is highly involved in major MS symptoms, such as fatigue, spasticity or pain. Cortical dysfunction in MS can be studied with neurophysiological tools such as electroencephalography (EEG and related techniques (evoked potentials – EPs or transcranial magnetic stimulation (TMS. These techniques are now widely used to provide essential elements of MS diagnosis and can also be used to modulate plasticity. Indeed the recent development of non-invasive brain stimulation (NIBS techniques able to induce cortical plasticity, such as repetitive TMS or transcranial direct current stimulation (tDCS, has brought promising results as add-on treatments.In this review we will focus on the use of these tools (EEG, TMS to study plasticity in MS and on the major techniques used to modulate plasticity in MS.

  18. The Neurophysiologist Perspective into MS Plasticity.

    Science.gov (United States)

    Houdayer, Elise; Comi, Giancarlo; Leocani, Letizia

    2015-01-01

    Multiple sclerosis (MS) is a frequent, highly debilitating inflammatory demyelinating disease, starting to manifest in early adulthood and presenting a wide variety of symptoms, which are often resistant to pharmacological treatments. Cortical dysfunctions have been demonstrated to be key components of MS condition, and plasticity of the corticospinal motor system is highly involved in major MS symptoms, such as fatigue, spasticity, or pain. Cortical dysfunction in MS can be studied with neurophysiological tools, such as electroencephalography (EEG) and related techniques (evoked potentials) or transcranial magnetic stimulation (TMS). These techniques are now widely used to provide essential elements of MS diagnosis and can also be used to modulate plasticity. Indeed, the recent development of non-invasive brain stimulation techniques able to induce cortical plasticity, such as repetitive TMS or transcranial direct current stimulation, has brought promising results as add-on treatments. In this review, we will focus on the use of these tools (EEG and TMS) to study plasticity in MS and on the major techniques used to modulate plasticity in MS.

  19. Phyllosphere yeasts rapidly break down biodegradable plastics

    Science.gov (United States)

    2011-01-01

    The use of biodegradable plastics can reduce the accumulation of environmentally persistent plastic wastes. The rate of degradation of biodegradable plastics depends on environmental conditions and is highly variable. Techniques for achieving more consistent degradation are needed. However, only a few microorganisms involved in the degradation process have been isolated so far from the environment. Here, we show that Pseudozyma spp. yeasts, which are common in the phyllosphere and are easily isolated from plant surfaces, displayed strong degradation activity on films made from poly-butylene succinate or poly-butylene succinate-co-adipate. Strains of P. antarctica isolated from leaves and husks of paddy rice displayed strong degradation activity on these films at 30°C. The type strain, P. antarctica JCM 10317, and Pseudozyma spp. strains from phyllosphere secreted a biodegradable plastic-degrading enzyme with a molecular mass of about 22 kDa. Reliable source of biodegradable plastic-degrading microorganisms are now in our hands. PMID:22126328

  20. Role of Plastics on Human Health.

    Science.gov (United States)

    Kumar, Pramod

    2018-05-01

    Plastics, currently the universal workhorse materials of modern economy, because of their low cost and varied functional properties are posing serious threat to environment and consumer's health in many direct and indirect ways. Rising concern about the impact of plastics on environment and human health, has forced the industry to look for alternatives. This review studies current understanding of benefits and concerns surrounding use of plastics, reviews literature about health effects in humans and discusses the current state of evidence, as well as future research trends. There is increasing concern regarding additives in plastics to which most people are exposed, such as phthalates, bisphenol A or polybrominated diphenyl ethers (PBDE), and their detection in humans, leading to harmful impact on health. The studies are divided, among many other issues on the fact of considering these additives as carcinogens or toxicants, but there is a consensus that these chemicals have the ability to alter the endocrine system. Human data are limited compared to large body of experimental evidence documenting reproductive or developmental toxicity in relation to these compounds in animals. The concentrations of these additives in young children, a segment particularly sensitive to exogenous insults, are typically higher, indicating the need to decrease exposure to these compounds. The rapid increase in usage of plastics and increased awareness about its health hazard has lent urgency to the whole issue.

  1. Epigenetic Basis of Neuronal and Synaptic Plasticity.

    Science.gov (United States)

    Karpova, Nina N; Sales, Amanda J; Joca, Samia R

    2017-01-01

    Neuronal network and plasticity change as a function of experience. Altered neural connectivity leads to distinct transcriptional programs of neuronal plasticity-related genes. The environmental challenges throughout life may promote long-lasting reprogramming of gene expression and the development of brain disorders. The modifications in neuronal epigenome mediate gene-environmental interactions and are required for activity-dependent regulation of neuronal differentiation, maturation and plasticity. Here, we highlight the latest advances in understanding the role of the main players of epigenetic machinery (DNA methylation and demethylation, histone modifications, chromatin-remodeling enzymes, transposons, and non-coding RNAs) in activity-dependent and long- term neural and synaptic plasticity. The review focuses on both the transcriptional and post-transcriptional regulation of gene expression levels, including the processes of promoter activation, alternative splicing, regulation of stability of gene transcripts by natural antisense RNAs, and alternative polyadenylation. Further, we discuss the epigenetic aspects of impaired neuronal plasticity and the pathogenesis of neurodevelopmental (Rett syndrome, Fragile X Syndrome, genomic imprinting disorders, schizophrenia, and others), stressrelated (mood disorders) and neurodegenerative Alzheimer's, Parkinson's and Huntington's disorders. The review also highlights the pharmacological compounds that modulate epigenetic programming of gene expression, the potential treatment strategies of discussed brain disorders, and the questions that should be addressed during the development of effective and safe approaches for the treatment of brain disorders.

  2. Optical absorption in recycled waste plastic polyethylene

    Science.gov (United States)

    Aji, M. P.; Rahmawati, I.; Priyanto, A.; Karunawan, J.; Wati, A. L.; Aryani, N. P.; Susanto; Wibowo, E.; Sulhadi

    2018-03-01

    We investigated the optical properties of UV spectrum absorption in recycled waste plastic from polyethylene polymer type. Waste plastic polyethylene showed an optical spectrum absorption after it’s recycling process. Spectrum absorption is determined using spectrophotometer UV-Nir Ocean Optics type USB 4000. Recycling method has been processed using heating treatment around the melting point temperature of the polyethylene polymer that are 200°C, 220°C, 240°C, 260°C, and 280°C. In addition, the recycling process was carried out with time variations as well, which are 1h, 1.5h, 2h, and 2.5h. The result of this experiment shows that recycled waste plastic polyethylene has a spectrum absorption in the ∼ 340-550 nm wavelength range. The absorbance spectrum obtained from UV light which is absorbed in the orbital n → π* and the orbital π → π*. This process indicates the existence of electron transition phenomena. This mechanism is affected by the temperature and the heating time where the intensity of absorption increases and widens with the increase of temperature and heating time. Furthermore this study resulted that the higher temperature affected the enhancement of the band gap energy of waste plastic polyethylene. These results show that recycled waste plastic polyethylene has a huge potential to be absorber materials for solar cell.

  3. Color change, phenotypic plasticity, and camouflage

    Directory of Open Access Journals (Sweden)

    Martin eStevens

    2016-05-01

    Full Text Available The ability to change appearance over a range of timescales is widespread in nature, existing in many invertebrate and vertebrate groups. This can include color change occurring in seconds, minutes, and hours, to longer term changes associated with phenotypic plasticity and development. A major function is for camouflage against predators because color change and plasticity enables animals to match their surroundings and potentially reduce the risk of predation. Recently, we published findings (Stevens et al. 2014a showing how shore crabs can change their appearance and better match the background to predator vision in the short term. This, coupled with a number of past studies, emphasizes the potential that animals have to modify their appearance for camouflage. However, the majority of studies on camouflage and color plasticity have focused on a small number of species capable of unusually rapid changes. There are many broad questions that remain about the nature, mechanisms, evolution, and adaptive value of color change and plasticity for concealment. Here, I discuss past work and outline six questions relating to color change and plasticity, as well as major avenues for future work.

  4. Investigation of plastic zones near SCC tips in a pipeline after hydrostatic testing

    International Nuclear Information System (INIS)

    Li Jian; Elboujdaini, M.; Gao, M.; Revie, R.W.

    2008-01-01

    Stress corrosion cracking (SCC) is an important failure mechanism for oil and gas pipelines. In the past, hydrostatic testing has been frequently used to assess and mitigate stress corrosion cracking. It is commonly agreed that an effective hydrostatic test not only eliminates critical crack-like flaws, but also blunts the sub-critical crack tip thereby suppressing further SCC propagation. However, little study has been done on the plastic deformation that results from the high stress intensity at the crack tip due to hydrostatic testing pressure and its possible role in subsequent SCC propagation. In this study, microstructural details were examined of an API 5L X52 SCC-containing pipe removed from field service. Plastic deformation generated by the hydrostatic testing pressure was revealed by using high-resolution imaging of a focused ion beam (FIB) microscope. The existence of the microscopic plastic zones around some crack tips suggests that caution should be taken when setting up pipeline hydrostatic tests

  5. Investigation of plastic zones near SCC tips in a pipeline after hydrostatic testing

    Energy Technology Data Exchange (ETDEWEB)

    Li Jian [Materials Technology Laboratory, Natural Resources Canada, 568 Booth Street, Ottawa, Ont., K1A 0G1 (Canada)], E-mail: jili@nrcan.gc.ca; Elboujdaini, M [Materials Technology Laboratory, Natural Resources Canada, 568 Booth Street, Ottawa, Ont., K1A 0G1 (Canada); Gao, M [Blade Energy Partners, 16225 Park Ten Place, Suite 450, Houston, TX 77084 (United States); Revie, R W [Materials Technology Laboratory, Natural Resources Canada, 568 Booth Street, Ottawa, Ont., K1A 0G1 (Canada)

    2008-07-15

    Stress corrosion cracking (SCC) is an important failure mechanism for oil and gas pipelines. In the past, hydrostatic testing has been frequently used to assess and mitigate stress corrosion cracking. It is commonly agreed that an effective hydrostatic test not only eliminates critical crack-like flaws, but also blunts the sub-critical crack tip thereby suppressing further SCC propagation. However, little study has been done on the plastic deformation that results from the high stress intensity at the crack tip due to hydrostatic testing pressure and its possible role in subsequent SCC propagation. In this study, microstructural details were examined of an API 5L X52 SCC-containing pipe removed from field service. Plastic deformation generated by the hydrostatic testing pressure was revealed by using high-resolution imaging of a focused ion beam (FIB) microscope. The existence of the microscopic plastic zones around some crack tips suggests that caution should be taken when setting up pipeline hydrostatic tests.

  6. Healing behavior of preexisting hydrogen micropores in aluminum alloys during plastic deformation

    International Nuclear Information System (INIS)

    Toda, H.; Minami, K.; Koyama, K.; Ichitani, K.; Kobayashi, M.; Uesugi, K.; Suzuki, Y.

    2009-01-01

    Synchrotron X-ray microtomography was used to observe the shrinkage and annihilation behaviors of hydrogen micropores in three dimensions during hot and cold plastic deformation of an Al-Mg alloy. Whether complete healing of micropores is achieved after plastic deformation was examined by exposing the material to a high temperature after plastic deformation. Although micropores generally show a pattern of shrinking and closing, closer inspection of a single specimen revealed a variety of geometrically variable behaviors. It is noteworthy that some of the micropores are reinitiated in positions identical to those before their annihilation, even after an 8-22% macroscopic strain has been further applied after annihilation. We attribute local variations such as these to significant local strain variation, which we measured in a series of tomographic volumes by tracking the microstructural features.

  7. Crucial roles of NGF in dorsal horn plasticity in partially deafferentated cats.

    Science.gov (United States)

    Liu, Jia; Chen, Shan-Shan; Dan, Qi-Qin; Rong, Rong; Zhou, Xue; Zhang, Lian-Feng; Wang, Ting-Hua

    2011-04-01

    Though exogenous nerve growth factor (NGF) has been implicated in spinal cord plasticity, whether endogenous NGF plays a crucial role has not been established in vivo. This study investigated first the role of endogenous NGF in spinal dorsal horn (DH) plasticity following removal of L1-L5 and L7-S2 dorsal root ganglions (DRGs) in cats. Co-culture of chick embryo DRG with DH condition media, protein band fishing by cells as well as western blot showed that NGF could promote neurite growth in vitro. Immunohistochemistry and in situ hybridization technique revealed an increase in the NGF and NGF mRNA immunoreactive cells in the DH after partial deafferentation. Lastly, after blocking with NGF antibody, choleragen subunit B horseradish peroxidase (CB-HRP) tracing showed a reduction in the neuronal sprouting observed in the DH. Our results demonstrated that in the cat, endogenous NGF plays a crucial role in DH plasticity after partial deafferentation.

  8. Hydrogen-induced room-temperature plasticity in TC4 and TC21 alloys

    DEFF Research Database (Denmark)

    Yuan, Baoguo; Jin, Yongyue; Hong, Chuanshi

    2017-01-01

    In order to reveal the effect of hydrogen on the room-temperature plasticity of the titanium alloys TC4 and TC21, compression tests have been carried out at room temperature. Results show that an appropriate amount of hydrogen can improve the room-temperature plasticity of both the TC4 and TC21...... alloys. The ultimate compression strain of the TC4 alloy containing a hydrogen concentration of 0.5 wt.% increases by 39% compared to the untreated material. For the TC21 alloy the ultimate compression strain is increased by 33% at a hydrogen concentration of 0.6 wt.%. The main reason for the improvement...... of hydrogen-induced room-temperature plasticity of the TC4 and TC21 alloys is discussed....

  9. Combined toxicity of mercury and plastic wastes to crustacean and gastropod inhabiting the waters in Kuwait.

    Science.gov (United States)

    Bu-Olayan, A H; Thomas, B V

    2015-11-01

    The present study determined total mercury (T-Hg) in crustacean Portunus pelagicus (blue crab) and mollusc Tapes sulcarius (Furrowed Venus: Cockle) following suspected rise in beach plastic wastes and their effect on marine organisms. Live samples were collected from beaches representing six Kuwait Governorate areas and exposed to toxicity (96hr) and bio accumulation tests for 180 d with inclusion of plastic wastes and environmental conditions simulated in laboratory. Results revealed high T-Hg concentrations in T sulcarius (1.44ng l(-1)) compared to P. pelagicus (1.03ng l(-1)) during winter than summer, with bio accumulation factor (BAF) > 1 labelled these species as hyper-accumulators. Significantly, combination of T-Hg concentrations from plastic wastes and in seawater validated the possibilities of detrimental effects of other marine lives besides deteriorating the aesthetic values of scenic beaches and likelihood of invasive species in such coastal areas.

  10. Size-Tuned Plastic Flow Localization in Irradiated Materials at the Submicron Scale

    Science.gov (United States)

    Cui, Yinan; Po, Giacomo; Ghoniem, Nasr

    2018-05-01

    Three-dimensional discrete dislocation dynamics (3D-DDD) simulations reveal that, with reduction of sample size in the submicron regime, the mechanism of plastic flow localization in irradiated materials transitions from irradiation-controlled to an intrinsic dislocation source controlled. Furthermore, the spatial correlation of plastic deformation decreases due to weaker dislocation interactions and less frequent cross slip as the system size decreases, thus manifesting itself in thinner dislocation channels. A simple model of discrete dislocation source activation coupled with cross slip channel widening is developed to reproduce and physically explain this transition. In order to quantify the phenomenon of plastic flow localization, we introduce a "deformation localization index," with implications to the design of radiation-resistant materials.

  11. Influence of Cellulose on the Mechanical and Thermal Stability of ABS Plastic Composites

    Directory of Open Access Journals (Sweden)

    K. Crews

    2016-01-01

    Full Text Available Microcrystalline cellulose was explored as possible biodegradable fillers in the fabrication of ABS plastic composites. TGA indicates that upon inclusion of cellulose microcrystals the thermal stability of the ABS plastics was improved significantly when compared to the neat ABS plastic counterparts. Furthermore, inclusion of extracted cellulose from plant biomass showed a higher thermal stability with maximum decomposition temperatures around 131.95°C and 124.19°C for cellulose from cotton and Hibiscus sabdariffa, respectively, when compared to that of the purchased cellulose. In addition, TMA revealed that the average CTE value for the neat ABS and 1 : 1 ratio of cellulose to ABS fabricated in this study was significantly lower than the reported CTE (ca. 73.8 μm/m°C.

  12. The Effect of a Plasticizing Admixture on the Properties of Hardened Concrete

    Directory of Open Access Journals (Sweden)

    Anastasija Abasova

    2012-11-01

    Full Text Available Concrete is material obtained mixing matrix material, coarse and small aggregates and water along with additives acquiring necessary properties of hardening. The quality and properties of raw material used for manufacturing concrete, V/C ratio and the uniformity of the compaction of the mixture lead to the fundamental properties of concrete. The compressive strength of concrete is one of the most important properties of concrete. The article deals with the impact of plasticizers on the structural properties of concrete choosing an optimal content of additives. Concrete plasticizers increasing the content of additive increase the strength of samples, the density and ultrasonic pulse of velocity and decrease absorption. Test results have revealed that a plasticizing admixture under dosing or overdosing can reduce the properties of concrete.

  13. Investigation of grain subdivision at very low plastic strains in a magnesium alloy

    Energy Technology Data Exchange (ETDEWEB)

    Hong, X. [Key Laboratory of Advanced Materials (MOE), School of Materials Science and Engineering, Tsinghua University, Beijing 100084 (China); Godfrey, A., E-mail: awgodfrey@mail.tsinghua.edu.cn [Key Laboratory of Advanced Materials (MOE), School of Materials Science and Engineering, Tsinghua University, Beijing 100084 (China); Zhang, C.L.; Liu, W. [Key Laboratory of Advanced Materials (MOE), School of Materials Science and Engineering, Tsinghua University, Beijing 100084 (China); Chapuis, A. [College of Materials Science and Engineering, Chongqing University, Chongqing 400044 (China)

    2017-05-02

    In-situ tensile loading combined with electron backscatter diffraction (EBSD) measurements has been used to investigate the plastic deformation of a magnesium alloy. A novel EBSD mapping is presented, based on construction of maps showing the rotation axis component in the sample coordinate frame of the misorientation from each pixel to the average grain orientation in the deformed sample. Using this mapping it is shown that the pattern of grain subdivision, even at very low plastic strains, can be revealed simultaneously in a large number of grains. In addition, it is demonstrated how maps of the rotation axis corresponding to the misorientation between each pixel and the initial grain orientation provide complimentary information directly useful for crystal plasticity analysis. A detailed slip system analysis shows that the grain subdivision can be accounted for according to the low energy dislocation structures (LEDS) model of work-hardening by differences in the slip amplitudes within different parts of each grain.

  14. 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.

  15. PLASTICITY OF THE BERRY RIPENING PROGRAM IN A WHITE GRAPE VARIETY

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    Silvia Dal Santo

    2016-07-01

    Full Text Available Grapevine (Vitis vinifera L is considered one of the most environmentally sensitive crops and is characterized by broad phenotypic plasticity, offering important advantages such as the large range of different wines that can be produced from the same cultivar, and the adaptation of existing cultivars to diverse growing regions. The uniqueness of berry quality traits reflects complex interactions between the grapevine plant and the combination of natural factors and human cultural practices, defined as terroir, which leads to the expression of wine typicity. Despite the scientific and commercial importance of genotype interactions with growing conditions, few studies have characterized the genes and metabolites directly involved in this phenomenon. Here we used two large-scale analytical approaches to explore the metabolomic and transcriptomic basis of the broad phenotypic plasticity of Garganega, a white berry variety grown at four sites characterized by different pedoclimatic conditions (altitudes, soil texture and composition. These conditions determine berry ripening dynamics in terms of sugar accumulation and the abundance of phenolic compounds. Multivariate analysis unraveled a highly plastic metabolomic response to different environments, especially the accumulation of hydroxycinnamic and hydroxybenzoic acids and flavonols. Principal component analysis revealed that the four sites strongly affected the berry transcriptome allowing the identification of environmentally-modulated genes and the plasticity of commonly-modulated transcripts at different sites. Many genes that control transcription, translation, transport and carbohydrate metabolism showed different expression depending on the environmental conditions, indicating a key role in the observed transcriptomic plasticity of Garganega berries. Interestingly, genes representing the phenylpropanoid/flavonoid pathway showed plastic responses to the environment mirroring the accumulation

  16. A finite difference method for off-fault plasticity throughout the earthquake cycle

    Science.gov (United States)

    Erickson, Brittany A.; Dunham, Eric M.; Khosravifar, Arash

    2017-12-01

    We have developed an efficient computational framework for simulating multiple earthquake cycles with off-fault plasticity. The method is developed for the classical antiplane problem of a vertical strike-slip fault governed by rate-and-state friction, with inertial effects captured through the radiation-damping approximation. Both rate-independent plasticity and viscoplasticity are considered, where stresses are constrained by a Drucker-Prager yield condition. The off-fault volume is discretized using finite differences and tectonic loading is imposed by displacing the remote side boundaries at a constant rate. Time-stepping combines an adaptive Runge-Kutta method with an incremental solution process which makes use of an elastoplastic tangent stiffness tensor and the return-mapping algorithm. Solutions are verified by convergence tests and comparison to a finite element solution. We quantify how viscosity, isotropic hardening, and cohesion affect the magnitude and off-fault extent of plastic strain that develops over many ruptures. If hardening is included, plastic strain saturates after the first event and the response during subsequent ruptures is effectively elastic. For viscoplasticity without hardening, however, successive ruptures continue to generate additional plastic strain. In all cases, coseismic slip in the shallow sub-surface is diminished compared to slip accumulated at depth during interseismic loading. The evolution of this slip deficit with each subsequent event, however, is dictated by the plasticity model. Integration of the off-fault plastic strain from the viscoplastic model reveals that a significant amount of tectonic offset is accommodated by inelastic deformation ( ∼ 0.1 m per rupture, or ∼ 10% of the tectonic deformation budget).

  17. Mirror trends of plasticity and stability indicators in primate prefrontal cortex.

    Science.gov (United States)

    García-Cabezas, Miguel Á; Joyce, Mary Kate P; John, Yohan J; Zikopoulos, Basilis; Barbas, Helen

    2017-10-01

    Research on plasticity markers in the cerebral cortex has largely focused on their timing of expression and role in shaping circuits during critical and normal periods. By contrast, little attention has been focused on the spatial dimension of plasticity-stability across cortical areas. The rationale for this analysis is based on the systematic variation in cortical structure that parallels functional specialization and raises the possibility of varying levels of plasticity. Here, we investigated in adult rhesus monkeys the expression of markers related to synaptic plasticity or stability in prefrontal limbic and eulaminate areas that vary in laminar structure. Our findings revealed that limbic areas are impoverished in three markers of stability: intracortical myelin, the lectin Wisteria floribunda agglutinin, which labels perineuronal nets, and parvalbumin, which is expressed in a class of strong inhibitory neurons. By contrast, prefrontal limbic areas were enriched in the enzyme calcium/calmodulin-dependent protein kinase II (CaMKII), known to enhance plasticity. Eulaminate areas have more elaborate laminar architecture than limbic areas and showed the opposite trend: they were enriched in markers of stability and had lower expression of the plasticity-related marker CaMKII. The expression of glial fibrillary acidic protein (GFAP), a marker of activated astrocytes, was also higher in limbic areas, suggesting that cellular stress correlates with the rate of circuit reshaping. Elevated markers of plasticity may endow limbic areas with flexibility necessary for learning and memory within an affective context, but may also render them vulnerable to abnormal structural changes, as seen in neurologic and psychiatric diseases. © 2017 Federation of European Neuroscience Societies and John Wiley & Sons Ltd.

  18. Adult plasticity in the subcortical auditory pathway of the maternal mouse.

    Directory of Open Access Journals (Sweden)

    Jason A Miranda

    Full Text Available Subcortical auditory nuclei were traditionally viewed as non-plastic in adulthood so that acoustic information could be stably conveyed to higher auditory areas. Studies in a variety of species, including humans, now suggest that prolonged acoustic training can drive long-lasting brainstem plasticity. The neurobiological mechanisms for such changes are not well understood in natural behavioral contexts due to a relative dearth of in vivo animal models in which to study this. Here, we demonstrate in a mouse model that a natural life experience with increased demands on the auditory system - motherhood - is associated with improved temporal processing in the subcortical auditory pathway. We measured the auditory brainstem response to test whether mothers and pup-naïve virgin mice differed in temporal responses to both broadband and tone stimuli, including ultrasonic frequencies found in mouse pup vocalizations. Mothers had shorter latencies for early ABR peaks, indicating plasticity in the auditory nerve and the cochlear nucleus. Shorter interpeak latency between waves IV and V also suggest plasticity in the inferior colliculus. Hormone manipulations revealed that these cannot be explained solely by estrogen levels experienced during pregnancy and parturition in mothers. In contrast, we found that pup-care experience, independent of pregnancy and parturition, contributes to shortening auditory brainstem response latencies. These results suggest that acoustic experience in the maternal context imparts plasticity on early auditory processing that lasts beyond pup weaning. In addition to establishing an animal model for exploring adult auditory brainstem plasticity in a neuroethological context, our results have broader implications for models of perceptual, behavioral and neural changes that arise during maternity, where subcortical sensorineural plasticity has not previously been considered.

  19. Adult plasticity in the subcortical auditory pathway of the maternal mouse.

    Science.gov (United States)

    Miranda, Jason A; Shepard, Kathryn N; McClintock, Shannon K; Liu, Robert C

    2014-01-01

    Subcortical auditory nuclei were traditionally viewed as non-plastic in adulthood so that acoustic information could be stably conveyed to higher auditory areas. Studies in a variety of species, including humans, now suggest that prolonged acoustic training can drive long-lasting brainstem plasticity. The neurobiological mechanisms for such changes are not well understood in natural behavioral contexts due to a relative dearth of in vivo animal models in which to study this. Here, we demonstrate in a mouse model that a natural life experience with increased demands on the auditory system - motherhood - is associated with improved temporal processing in the subcortical auditory pathway. We measured the auditory brainstem response to test whether mothers and pup-naïve virgin mice differed in temporal responses to both broadband and tone stimuli, including ultrasonic frequencies found in mouse pup vocalizations. Mothers had shorter latencies for early ABR peaks, indicating plasticity in the auditory nerve and the cochlear nucleus. Shorter interpeak latency between waves IV and V also suggest plasticity in the inferior colliculus. Hormone manipulations revealed that these cannot be explained solely by estrogen levels experienced during pregnancy and parturition in mothers. In contrast, we found that pup-care experience, independent of pregnancy and parturition, contributes to shortening auditory brainstem response latencies. These results suggest that acoustic experience in the maternal context imparts plasticity on early auditory processing that lasts beyond pup weaning. In addition to establishing an animal model for exploring adult auditory brainstem plasticity in a neuroethological context, our results have broader implications for models of perceptual, behavioral and neural changes that arise during maternity, where subcortical sensorineural plasticity has not previously been considered.

  20. Reversal of Cocaine-Associated Synaptic Plasticity in Medial Prefrontal Cortex Parallels Elimination of Memory Retrieval.

    Science.gov (United States)

    Otis, James M; Mueller, Devin

    2017-09-01

    Addiction is characterized by abnormalities in prefrontal cortex that are thought to allow drug-associated cues to drive compulsive drug seeking and taking. Identification and reversal of these pathologic neuroadaptations are therefore critical for treatment of addiction. Previous studies using rodents reveal that drugs of abuse cause dendritic spine plasticity in prelimbic medial prefrontal cortex (PL-mPFC) pyramidal neurons, a phenomenon that correlates with the strength of drug-associated memories in vivo. Thus, we hypothesized that cocaine-evoked plasticity in PL-mPFC may underlie cocaine-associated memory retrieval, and therefore disruption of this plasticity would prevent retrieval. Indeed, using patch clamp electrophysiology we find that cocaine place conditioning increases excitatory presynaptic and postsynaptic transmission in rat PL-mPFC pyramidal neurons. This was accounted for by increases in excitatory presynaptic release, paired-pulse facilitation, and increased AMPA receptor transmission. Noradrenergic signaling is known to maintain glutamatergic plasticity upon reactivation of modified circuits, and we therefore next determined whether inhibition of noradrenergic signaling during memory reactivation would reverse the cocaine-evoked plasticity and/or disrupt the cocaine-associated memory. We find that administration of the β-adrenergic receptor antagonist propranolol before memory retrieval, but not after (during memory reconsolidation), reverses the cocaine-evoked presynaptic and postsynaptic modifications in PL-mPFC and causes long-lasting memory impairments. Taken together, these data reveal that cocaine-evoked synaptic plasticity in PL-mPFC is reversible in vivo, and suggest a novel strategy that would allow normalization of prefrontal circuitry in addiction.