Gap effects on leaf traits of tropical rainforest trees differing in juvenile light requirement.

PubMed

Houter, Nico C; Pons, Thijs L

2014-05-01

The relationships of 16 leaf traits and their plasticity with the dependence of tree species on gaps for regeneration (gap association index; GAI) were examined in a Neotropical rainforest. Young saplings of 24 species with varying GAI were grown under a closed canopy, in a medium-sized and in a large gap, thus capturing the full range of plasticity with respect to canopy openness. Structural, biomechanical, chemical and photosynthetic traits were measured. At the chloroplast level, the chlorophyll a/b ratio and plasticity in this variable were not related to the GAI. However, plasticity in total carotenoids per unit chlorophyll was larger in shade-tolerant species. At the leaf level, leaf mass per unit area (LMA) decreased with the GAI under the closed canopy and in the medium gap, but did not significantly decrease with the GAI in the large gap. This was a reflection of the larger plasticity in LMA and leaf thickness of gap-dependent species. The well-known opposite trends in LMA for adaptation and acclimation to high irradiance in evergreen tropical trees were thus not invariably found. Although leaf strength was dependent on LMA and thickness, plasticity in this trait was not related to the GAI. Photosynthetic capacity expressed on each basis increased with the GAI, but the large plasticity in these traits was not clearly related to the GAI. Although gap-dependent species tended to have a greater plasticity overall, as evident from a principle component analysis, leaf traits of gap-dependent species are thus not invariably more phenotypically plastic.

As main meal for sperm whales: plastics debris.

PubMed

de Stephanis, Renaud; Giménez, Joan; Carpinelli, Eva; Gutierrez-Exposito, Carlos; Cañadas, Ana

2013-04-15

Marine debris has been found in marine animals since the early 20th century, but little is known about the impacts of the ingestion of debris in large marine mammals. In this study we describe a case of mortality of a sperm whale related to the ingestion of large amounts of marine debris in the Mediterranean Sea (4th published case worldwide to our knowledge), and discuss it within the context of the spatial distribution of the species and the presence of anthropogenic activities in the area that could be the source of the plastic debris found inside the sperm whale. The spatial distribution modelled for the species in the region shows that these animals can be seen in two distinct areas: near the waters of Almería, Granada and Murcia and in waters near the Strait of Gibraltar. The results shows how these animals feed in waters near an area completely flooded by the greenhouse industry, making them vulnerable to its waste products if adequate treatment of this industry's debris is not in place. Most types of these plastic materials have been found in the individual examined and cause of death was presumed to be gastric rupture following impaction with debris, which added to a previous problem of starvation. The problem of plastics arising from greenhouse agriculture should have a relevant section in the conservation plans and should be a recommendation from ACCOBAMS due to these plastics' and sperm whales' high mobility in the Mediterranean Sea. Copyright © 2013 Elsevier Ltd. All rights reserved.

Plastic litter in aquatic environments of Maremma Regional Park (Tyrrhenian Sea, Italy): Contribution by the Ombrone river and levels in marine sediments.

PubMed

Guerranti, Cristiana; Cannas, Susanna; Scopetani, Costanza; Fastelli, Paolo; Cincinelli, Alessandra; Renzi, Monia

2017-04-15

During two surveys in 2015 and 2016, sediments samples were collected along the Ombrone river (Maremma Regional Park, province of Grosseto, Italy), in particular at its mouth and in the marine area in front of it, in order to quantify, identify and categorize plastic items (macro, meso and micro-plastics and colour, material etc.) and evaluate their potential sources. The Albegna and Osa rivers were identified as external areas of comparison. The results of the analysis showed different situations, especially as regards fluvial inputs, in addition to evidencing local provisions of plastic material derived from agricultural activities. The microplastics values per kg of sediment and the prevailing type of items found largely varied between the investigated sites (45-1069items/kg dry sample). Copyright © 2017 Elsevier Ltd. All rights reserved.

Practical Aspects of Access Network Indoor Extensions Using Multimode Glass and Plastic Optical Fibers

NASA Astrophysics Data System (ADS)

Keiser, Gerd; Liu, Hao-Yu; Lu, Shao-Hsi; Devi Pukhrambam, Puspa

2012-07-01

Low-cost multimode glass and plastic optical fibers are attractive for high-capacity indoor telecom networks. Many existing buildings already have glass multimode fibers installed for local area network applications. Future indoor applications will use combinations of glass multimode fibers with plastic optical fibers that have low losses in the 850-nm-1,310-nm range. This article examines real-world link losses when randomly interconnecting glass and plastic fiber segments having factory-installed connectors. Potential interconnection issues include large variations in connector losses among randomly selected fiber segments, asymmetric link losses in bidirectional links, and variations in bandwidths among different types of fibers.

Professional perceptions of plastic and reconstructive surgery: what primary care physicians think.

PubMed

Tanna, Neil; Patel, Nitin J; Azhar, Hamdan; Granzow, Jay W

2010-08-01

The great breadth of the specialty of plastic surgery is often misunderstood by practitioners in other specialties and by the public at large. The authors investigate the perceptions of primary care physicians in training toward the practice of different areas of plastic and reconstructive surgery. A short, anonymous, Web-based survey was administered to residents of internal medicine, family medicine, and pediatrics training programs in the United States. Respondents were asked to choose the specialist they perceived to be an expert for six specific clinical areas, including eyelid surgery, cleft lip and palate surgery, facial fractures, hand surgery, rhinoplasty, and skin cancer of the face. Specialists for selection included the following choices: dermatologist, general surgeon, ophthalmologist, oral and maxillofacial surgeon, orthopedic surgeon, otolaryngologist, and plastic surgeon. A total of 1020 usable survey responses were collected. Respondents believed the following specialists were experts for eyelid surgery (plastic surgeon, 70 percent; ophthalmologist, 59 percent; oral and maxillofacial surgeon, 15 percent; dermatologist, 5 percent; and otolaryngologist, 5 percent); cleft lip and palate surgery (oral and maxillofacial surgeon, 78 percent; plastic surgeon, 57 percent; and otolaryngologist, 36 percent); facial fractures (oral and maxillofacial surgeon, 88 percent; plastic surgeon, 36 percent; otolaryngologist, 30 percent; orthopedic surgeon, 11 percent; general surgeon, 3 percent; and ophthalmologist, 2 percent); hand surgery (orthopedic surgeon, 76 percent; plastic surgeon, 52 percent; and general surgeon, 7 percent); rhinoplasty (plastic surgeon, 76 percent; otolaryngologist, 45 percent; and oral and maxillofacial surgeon, 18 percent); and skin cancer of the face (dermatologist, 89 percent; plastic surgeon, 35 percent; oral and maxillofacial surgeon, 9 percent; otolaryngologist, 8 percent; and general surgeon, 7 percent). As the field of plastic surgery and other areas of medicine continue to evolve, additional education of internal medicine, pediatrics, and family practice physicians and trainees in the scope of plastic surgery practice will be critical.

Changes in the Floating Plastic Pollution of the Mediterranean Sea in Relation to the Distance to Land.

PubMed

Pedrotti, Maria Luiza; Petit, Stéphanie; Elineau, Amanda; Bruzaud, Stéphane; Crebassa, Jean-Claude; Dumontet, Bruno; Martí, Elisa; Gorsky, Gabriel; Cózar, Andrés

2016-01-01

The composition, size distribution, and abundance of floating plastic debris in surface waters of the Mediterranean Sea were analyzed in relation to distance to land. We combined data from previously published reports with an intensive sampling in inshore waters of the Northwestern Mediterranean. The highest plastic concentrations were found in regions distant from from land as well as in the first kilometer adjacent to the coastline. In this nearshore water strip, plastic concentrations were significantly correlated with the nearness to a coastal human population, with local areas close to large human settlements showing hundreds of thousands of plastic pieces per km2. The ratio of plastic to plankton abundance reached particularly high values for the coastal surface waters. Polyethylene, polypropylene and polyamides were the predominant plastic polymers at all distances from coast (86 to 97% of total items), although the diversity of polymers was higher in the 1-km coastal water strip due to a higher frequency of polystyrene or polyacrylic fibers. The plastic size distributions showed a gradual increase in abundance toward small sizes indicating an efficient removal of small plastics from the surface. Nevertheless, the relative abundance of small fragments (< 2 mm) was higher within the 1-km coastal water strip, suggesting a rapid fragmentation down along the shoreline, likely related with the washing ashore on the beaches. This study constitutes a first attempt to determine the impact of plastic debris in areas closest to Mediterranean coast. The presence of a high concentration of plastic including tiny plastic items could have significant environmental, health and economic impacts.

Changes in the Floating Plastic Pollution of the Mediterranean Sea in Relation to the Distance to Land

PubMed Central

Petit, Stéphanie; Elineau, Amanda; Bruzaud, Stéphane; Crebassa, Jean-Claude; Dumontet, Bruno; Martí, Elisa; Gorsky, Gabriel; Cózar, Andrés

2016-01-01

The composition, size distribution, and abundance of floating plastic debris in surface waters of the Mediterranean Sea were analyzed in relation to distance to land. We combined data from previously published reports with an intensive sampling in inshore waters of the Northwestern Mediterranean. The highest plastic concentrations were found in regions distant from from land as well as in the first kilometer adjacent to the coastline. In this nearshore water strip, plastic concentrations were significantly correlated with the nearness to a coastal human population, with local areas close to large human settlements showing hundreds of thousands of plastic pieces per km2. The ratio of plastic to plankton abundance reached particularly high values for the coastal surface waters. Polyethylene, polypropylene and polyamides were the predominant plastic polymers at all distances from coast (86 to 97% of total items), although the diversity of polymers was higher in the 1-km coastal water strip due to a higher frequency of polystyrene or polyacrylic fibers. The plastic size distributions showed a gradual increase in abundance toward small sizes indicating an efficient removal of small plastics from the surface. Nevertheless, the relative abundance of small fragments (< 2 mm) was higher within the 1-km coastal water strip, suggesting a rapid fragmentation down along the shoreline, likely related with the washing ashore on the beaches. This study constitutes a first attempt to determine the impact of plastic debris in areas closest to Mediterranean coast. The presence of a high concentration of plastic including tiny plastic items could have significant environmental, health and economic impacts. PMID:27556233

Strain-Based Design Methodology of Large Diameter Grade X80 Linepipe

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lower, Mark D.

2014-04-01

Continuous growth in energy demand is driving oil and natural gas production to areas that are often located far from major markets where the terrain is prone to earthquakes, landslides, and other types of ground motion. Transmission pipelines that cross this type of terrain can experience large longitudinal strains and plastic circumferential elongation as the pipeline experiences alignment changes resulting from differential ground movement. Such displacements can potentially impact pipeline safety by adversely affecting structural capacity and leak tight integrity of the linepipe steel. Planning for new long-distance transmission pipelines usually involves consideration of higher strength linepipe steels because theirmore » use allows pipeline operators to reduce the overall cost of pipeline construction and increase pipeline throughput by increasing the operating pressure. The design trend for new pipelines in areas prone to ground movement has evolved over the last 10 years from a stress-based design approach to a strain-based design (SBD) approach to further realize the cost benefits from using higher strength linepipe steels. This report presents an overview of SBD for pipelines subjected to large longitudinal strain and high internal pressure with emphasis on the tensile strain capacity of high-strength microalloyed linepipe steel. The technical basis for this report involved engineering analysis and examination of the mechanical behavior of Grade X80 linepipe steel in both the longitudinal and circumferential directions. Testing was conducted to assess effects on material processing including as-rolled, expanded, and heat treatment processing intended to simulate coating application. Elastic-plastic and low-cycle fatigue analyses were also performed with varying internal pressures. Proposed SBD models discussed in this report are based on classical plasticity theory and account for material anisotropy, triaxial strain, and microstructural damage effects developed from test data. The results are intended to enhance SBD and analysis methods for producing safe and cost effective pipelines capable of accommodating large plastic strains in seismically active arctic areas.« less

Investigation of plastic debris ingestion by four species of sea turtles collected as bycatch in pelagic Pacific longline fisheries

USGS Publications Warehouse

Clukey, Katherine E.; Lepczyk, Christopher A.; Balazs, George H.; Work, Thierry M.; Lynch, Jennifer M.

2017-01-01

Ingestion of marine debris is an established threat to sea turtles. The amount, type, color and location of ingested plastics in the gastrointestinal tracts of 55 sea turtles from Pacific longline fisheries from 2012 to 2016 were quantified, and compared across species, turtle length, body condition, sex, capture location, season and year. Six approaches for quantifying amounts of ingested plastic strongly correlated with one another and included: number of pieces, mass, volume and surface area of plastics, ratio of plastic mass to body mass, and percentage of the mass of gut contents consisting of plastic. All olive ridley (n = 37), 90% of green (n = 10), 80% of loggerhead (n = 5) and 0% of leatherback (n = 3) turtles had ingested plastic; green turtles ingested significantly more than olive ridleys. Most debris was in the large intestines. No adverse health impacts (intestinal lesions, blockage, or poor body condition) due directly to plastic ingestion were noted.

Investigation of plastic debris ingestion by four species of sea turtles collected as bycatch in pelagic Pacific longline fisheries.

PubMed

Clukey, Katharine E; Lepczyk, Christopher A; Balazs, George H; Work, Thierry M; Lynch, Jennifer M

2017-07-15

Ingestion of marine debris is an established threat to sea turtles. The amount, type, color and location of ingested plastics in the gastrointestinal tracts of 55 sea turtles from Pacific longline fisheries from 2012 to 2016 were quantified, and compared across species, turtle length, body condition, sex, capture location, season and year. Six approaches for quantifying amounts of ingested plastic strongly correlated with one another and included: number of pieces, mass, volume and surface area of plastics, ratio of plastic mass to body mass, and percentage of the mass of gut contents consisting of plastic. All olive ridley (n=37), 90% of green (n=10), 80% of loggerhead (n=5) and 0% of leatherback (n=3) turtles had ingested plastic; green turtles ingested significantly more than olive ridleys. Most debris was in the large intestines. No adverse health impacts (intestinal lesions, blockage, or poor body condition) due directly to plastic ingestion were noted. Copyright © 2017. Published by Elsevier Ltd.

Error driven remeshing strategy in an elastic-plastic shakedown problem

NASA Astrophysics Data System (ADS)

Pazdanowski, Michał J.

2018-01-01

A shakedown based approach has been for many years successfully used to calculate the distributions of residual stresses in bodies made of elastic-plastic materials and subjected to cyclic loads exceeding their bearing capacity. The calculations performed indicated the existence of areas characterized by extremely high gradients and rapid changes of sign over small areas in the stress field sought. In order to account for these changes in sign, relatively dense nodal meshes had to be used during calculations in disproportionately large parts of considered bodies, resulting in unnecessary expenditure of computer resources. Therefore the effort was undertaken to limit the areas of high mesh densities and drive the mesh regeneration algorithm by selected error indicators.

The Ratio of Leaf to Total Photosynthetic Area Influences Shade Survival and Plastic Response to Light of Green‐stemmed Leguminous Shrub Seedlings

PubMed Central

VALLADARES, FERNANDO; HERNÁNDEZ, LIBERTAD G.; DOBARRO, IKER; GARCÍA‐PÉREZ, CRISTINA; SANZ, RUBÉN; PUGNAIRE, FRANCISCO I.

2003-01-01

Different plant species and organs within a plant differ in their plastic response to light. These responses influence their performance and survival in relation to the light environment, which may range from full sunlight to deep shade. Plasticity, especially with regard to physiological features, is linked to a greater capacity to exploit high light and is usually low in shade‐tolerant species. Among photosynthetic organs, green stems, which represent a large fraction of the total photosynthetic area of certain species, are hypothesized to be less capable of adjustment to light than leaves, because of biomechanical and hydraulic constraints. The response to light by leaves and stems of six species of leguminous, green‐stemmed shrubs from dry and high‐light environments was studied by growing seedlings in three light environments: deep shade, moderate shade and sun (3, 30 and 100 % of full sunlight, respectively). Survival in deep shade ranged from 2 % in Retama sphaerocarpa to 74 % in Ulex europaeus. Survival was maximal at moderate shade in all species, ranging from 80 to 98 %. The six species differed significantly in their ratio of leaf to total photosynthetic area, which influenced their light response. Survival in deep shade increased significantly with increasing ratio of leaf to total photosynthetic area, and decreased with increasing plasticity in net photosynthesis and dark respiration. Responses to light differed between stems and leaves within each species. Mean phenotypic plasticity for the variables leaf or stem specific mass, chlorophyll content, chlorophyll a/b ratio, and carotenoid to chlorophyll ratio of leaves, was inversely related to that of stems. Although mean plasticity of stems increased with the ratio of leaf to total photosynthetic area, the mean plasticity of leaves decreased. Shrubs with green stems and a low ratio of leaf to total photosynthetic area are expected to be restricted to well‐lit habitats, at least during the seedling stage, owing to their inefficient light capture and the low plasticity of their stems. PMID:12646502

5 × 5 cm2 silicon photonic crystal slabs on glass and plastic foil exhibiting broadband absorption and high-intensity near-fields

PubMed Central

Becker, C.; Wyss, P.; Eisenhauer, D.; Probst, J.; Preidel, V.; Hammerschmidt, M.; Burger, S.

2014-01-01

Crystalline silicon photonic crystal slabs are widely used in various photonics applications. So far, the commercial success of such structures is still limited owing to the lack of cost-effective fabrication processes enabling large nanopatterned areas (≫ 1 cm2). We present a simple method for producing crystalline silicon nanohole arrays of up to 5 × 5 cm2 size with lattice pitches between 600 and 1000 nm on glass and flexible plastic substrates. Exclusively up-scalable, fast fabrication processes are applied such as nanoimprint-lithography and silicon evaporation. The broadband light trapping efficiency of the arrays is among the best values reported for large-area experimental crystalline silicon nanostructures. Further, measured photonic crystal resonance modes are in good accordance with light scattering simulations predicting strong near-field intensity enhancements greater than 500. Hence, the large-area silicon nanohole arrays might become a promising platform for ultrathin solar cells on lightweight substrates, high-sensitive optical biosensors, and nonlinear optics. PMID:25073935

Plastic-Film Mulching for Enhanced Water-Use Efficiency and Economic Returns from Maize Fields in Semiarid China.

PubMed

Zhang, Peng; Wei, Ting; Cai, Tie; Ali, Shahzad; Han, Qingfang; Ren, Xiaolong; Jia, Zhikuan

2017-01-01

Film mulch has gradually been popularized to increase water availability to crops for improving and stabilizing agricultural production in the semiarid areas of Northwest China. To find more sustainable and economic film mulch methods for alleviating drought stress in semiarid region, it is necessary to test optimum planting methods in same cultivation conditions. A field experiment was conducted during 2013 and 2014 to evaluate the effects of different plastic film mulch methods on soil water, soil temperature, water use efficiency (WUE), yield and revenue. The treatments included: (i) the control, conventional flat planting without plastic film mulch (CK); (ii) flat planting with maize rows (60 cm spacing) on plastic film mulch (70 cm wide); (iii) furrow planting of maize (60 cm spacing), separated by consecutive plastic film-mulched ridges (each 50 cm wide and 15 cm tall); (iv) furrow planting of maize (60 cm spacing), separated by alternating large and small plastic film-mulched ridges (large ridges: 70 cm wide and 15 cm tall, small ridges 50 cm wide and 10 cm tall); and (v) furrow-flat planting of maize (60 cm spacing) with a large plastic film-mulched ridge (60 cm wide and 15 cm tall) alternating with a flat without plastic film-mulched space (60 cm wide). Topsoil temperature (5-25 cm) was significantly ( p < 0.05) higher in field plots with plastic film mulch than the control (CK), and resulted in greater soil water storage (0-200 cm) up to 40 days after planting. Maize grain yield and WUE were significantly ( p < 0.05) higher with the furrow planting methods (consecutive film-mulched ridges and alternating film-mulched ridges) than the check in both years. Maize yield was, on average, 29% ( p < 0.05) greater and 28% ( p < 0.05) greater with these furrow planting methods, while the average WUE increased by 22.8% ( p < 0.05) with consecutive film-mulched ridges and 21.1% ( p < 0.05) with alternating film-mulched ridges. The 2-year average net income increased by 1559, 528, and 350 Chinese Yuan (CNY) ha -1 with the consecutive film-mulched ridges, furrow-flat planting and alternating film-mulched ridges, respectively, compared with the control (CK). We conclude that the consecutive film-mulched ridge method was the most productive and profitable for maize in this semi-arid area with limited and erratic precipitation.

The specific light output of cesium iodide crystals

NASA Technical Reports Server (NTRS)

Gregory, J. C.

1976-01-01

Large area ion chambers for a high energy cosmic ray experiment, scintillating plastic fibers as light pipes for a cosmic ray hodoscope, and an evaluation of clad scintillating light pipes were considered.

Application of large area SiPMs for the readout of a plastic scintillator based timing detector

NASA Astrophysics Data System (ADS)

Betancourt, C.; Blondel, A.; Brundler, R.; Dätwyler, A.; Favre, Y.; Gascon, D.; Gomez, S.; Korzenev, A.; Mermod, P.; Noah, E.; Serra, N.; Sgalaberna, D.; Storaci, B.

2017-11-01

In this study an array of eight 6 mm × 6 mm area SiPMs was coupled to the end of a long plastic scintillator counter which was exposed to a 2.5 GeV/c muon beam at the CERN PS. Timing characteristics of bars with dimensions 150 cm × 6 cm × 1 cm and 120 cm × 11 cm × 2.5 cm have been studied. An 8-channel SiPM anode readout ASIC (MUSIC R1) based on a novel low input impedance current conveyor has been used to read out and amplify SiPMs independently and sum the signals at the end. Prospects for applications in large-scale particle physics detectors with timing resolution below 100 ps are provided in light of the results.

Nanotechnology and regenerative therapeutics in plastic surgery: The next frontier.

PubMed

Tan, Aaron; Chawla, Reema; G, Natasha; Mahdibeiraghdar, Sara; Jeyaraj, Rebecca; Rajadas, Jayakumar; Hamblin, Michael R; Seifalian, Alexander M

2016-01-01

The rapid ascent of nanotechnology and regenerative therapeutics as applied to medicine and surgery has seen an exponential rise in the scale of research generated in this field. This is evidenced not only by the sheer volume of papers dedicated to nanotechnology but also in a large number of new journals dedicated to nanotechnology and regenerative therapeutics specifically to medicine and surgery. Aspects of nanotechnology that have already brought benefits to these areas include advanced drug delivery platforms, molecular imaging and materials engineering for surgical implants. Particular areas of interest include nerve regeneration, burns and wound care, artificial skin with nanoelectronic sensors and head and neck surgery. This study presents a review of nanotechnology and regenerative therapeutics, with focus on its applications and implications in plastic surgery. Copyright © 2015 British Association of Plastic, Reconstructive and Aesthetic Surgeons. All rights reserved.

Increased plastic litter cover affects the foraging activity of the sandy intertidal gastropod Nassarius pullus.

PubMed

Aloy, Alexander B; Vallejo, Benjamin M; Juinio-Meñez, Marie Antonette

2011-08-01

This study analyzed the foraging behavior of the gastropod Nassarius pullus on garbage-impacted sandy shores of Talim Bay, Batangas, Philippines. The effect of different levels of plastic garbage cover on foraging efficiency was investigated. Controlled in situ baiting experiments were conducted to quantify aspects of foraging behavior as affected by the levels of plastic litter cover in the foraging area. The results of the study indicated that the gastropod's efficiency in locating and in moving towards a food item generally decreased as the level of plastic cover increased. Prolonged food searching time and increased self-burial in sand were highly correlated with increased plastic cover. The accuracy of orientation towards the actual position of the bait decreased significantly when the amount of plastic cover increased to 50%. These results are consistent with the significant decreases in the abundance of the gastropod observed during periods of deposition of large amounts of plastic and other debris on the shore. Copyright © 2011 Elsevier Ltd. All rights reserved.

Method for formation of thin film transistors on plastic substrates

DOEpatents

Carey, Paul G.; Smith, Patrick M.; Sigmon, Thomas W.; Aceves, Randy C.

1998-10-06

A process for formation of thin film transistors (TFTs) on plastic substrates replaces standard thin film transistor fabrication techniques, and uses sufficiently lower processing temperatures so that inexpensive plastic substrates may be used in place of standard glass, quartz, and silicon wafer-based substrates. The process relies on techniques for depositing semiconductors, dielectrics, and metals at low temperatures; crystallizing and doping semiconductor layers in the TFT with a pulsed energy source; and creating top-gate self-aligned as well as back-gate TFT structures. The process enables the fabrication of amorphous and polycrystalline channel silicon TFTs at temperatures sufficiently low to prevent damage to plastic substrates. The process has use in large area low cost electronics, such as flat panel displays and portable electronics.

Mapping plastic greenhouse with medium spatial resolution satellite data: Development of a new spectral index

NASA Astrophysics Data System (ADS)

Yang, Dedi; Chen, Jin; Zhou, Yuan; Chen, Xiang; Chen, Xuehong; Cao, Xin

2017-06-01

Plastic greenhouses (PGs) are an important agriculture development technique to protect and control the growing environment for food crops. The extensive use of PGs can change the agriculture landscape and affects the local environment. Accurately mapping and estimating the coverage of PGs is a necessity to the strategic planning of modern agriculture. Unfortunately, PG mapping over large areas is methodologically challenging, as the medium spatial resolution satellite imagery (such as Landsat data) used for analysis lacks spatial details and spectral variations. To fill the gap, the paper proposes a new plastic greenhouse index (PGI) based on the spectral, sensitivity, and separability analysis of PGs using medium spatial resolution images. In the context of the Landsat Enhanced Thematic Mapper Plus (ETM+) imagery, the paper examines the effectiveness and capability of the proposed PGI. The results indicate that PGs in Landsat ETM+ image can be successfully detected by the PGI if the PG fraction is greater than 12% in a mixed pixel. A kappa coefficient of 0.83 and overall accuracy of 91.2% were achieved when applying the proposed PGI in the case of Weifang District, Shandong, China. These results show that the proposed index can be applied to identifying transparent PGs in atmospheric corrected Landsat image and has the potential for the digital mapping of plastic greenhouse coverage over a large area.

Development of Methods of Characterizing Coal in Its Plastic State

NASA Technical Reports Server (NTRS)

Lloyd, W. G.

1978-01-01

Coal in its plastic state (typically 400-460 C) was examined by the isothermal Gieseler plastometry of seven selected coals of widely varying plastic properties. Kinetic models were proposed for the isothermal plastometric curves. Plastic behavior was compared with a variety of laboratory analyses and characterizations of these coals, including classical coal analysis; mineral analysis; microstructural analysis (extractable fractions, surface area measurement, and petrographic analysis); and thermal analysis (thermogravimetric analysis, thermomechanical analysis, and differential scanning calorimetry). The phenomenon of a sharp, large, poorly reproducible exotherm in the differential scanning calorimetric analysis of coking coals was examined. Several coal extrudates show mineral distribution, organic maceral composition and overall calorific value to be little affected by 800 F extrusion. Volatile matter and plastic properties are moderately reduced, and the network structure (as gauged by extractables) appears to be slightly degraded in the extrusion process.

The effect of inflammation and its reduction on brain plasticity in multiple sclerosis: MRI evidence

PubMed Central

d'Ambrosio, Alessandro; Petsas, Nikolaos; Wise, Richard G.; Sbardella, Emilia; Allen, Marek; Tona, Francesca; Fanelli, Fulvia; Foster, Catherine; Carnì, Marco; Gallo, Antonio; Pantano, Patrizia; Pozzilli, Carlo

2016-01-01

Abstract Brain plasticity is the basis for systems‐level functional reorganization that promotes recovery in multiple sclerosis (MS). As inflammation interferes with plasticity, its pharmacological modulation may restore plasticity by promoting desired patterns of functional reorganization. Here, we tested the hypothesis that brain plasticity probed by a visuomotor adaptation task is impaired with MS inflammation and that pharmacological reduction of inflammation facilitates its restoration. MS patients were assessed twice before (sessions 1 and 2) and once after (session 3) the beginning of Interferon beta (IFN beta), using behavioural and structural MRI measures. During each session, 2 functional MRI runs of a visuomotor task, separated by 25‐minutes of task practice, were performed. Within‐session between‐run change in task‐related functional signal was our imaging marker of plasticity. During session 1, patients were compared with healthy controls. Comparison of patients' sessions 2 and 3 tested the effect of reduced inflammation on our imaging marker of plasticity. The proportion of patients with gadolinium‐enhancing lesions reduced significantly during IFN beta. In session 1, patients demonstrated a greater between‐run difference in functional MRI activity of secondary visual areas and cerebellum than controls. This abnormally large practice‐induced signal change in visual areas, and in functionally connected posterior parietal and motor cortices, was reduced in patients in session 3 compared with 2. Our results suggest that MS inflammation alters short‐term plasticity underlying motor practice. Reduction of inflammation with IFN beta is associated with a restoration of this plasticity, suggesting that modulation of inflammation may enhance recovery‐oriented strategies that rely on patients' brain plasticity. Hum Brain Mapp 37:2431–2445, 2016. © 2016 The Authors Human Brain Mapping Published by Wiley Periodicals, Inc. PMID:26991559

The effect of inflammation and its reduction on brain plasticity in multiple sclerosis: MRI evidence.

PubMed

Tomassini, Valentina; d'Ambrosio, Alessandro; Petsas, Nikolaos; Wise, Richard G; Sbardella, Emilia; Allen, Marek; Tona, Francesca; Fanelli, Fulvia; Foster, Catherine; Carnì, Marco; Gallo, Antonio; Pantano, Patrizia; Pozzilli, Carlo

2016-07-01

Brain plasticity is the basis for systems-level functional reorganization that promotes recovery in multiple sclerosis (MS). As inflammation interferes with plasticity, its pharmacological modulation may restore plasticity by promoting desired patterns of functional reorganization. Here, we tested the hypothesis that brain plasticity probed by a visuomotor adaptation task is impaired with MS inflammation and that pharmacological reduction of inflammation facilitates its restoration. MS patients were assessed twice before (sessions 1 and 2) and once after (session 3) the beginning of Interferon beta (IFN beta), using behavioural and structural MRI measures. During each session, 2 functional MRI runs of a visuomotor task, separated by 25-minutes of task practice, were performed. Within-session between-run change in task-related functional signal was our imaging marker of plasticity. During session 1, patients were compared with healthy controls. Comparison of patients' sessions 2 and 3 tested the effect of reduced inflammation on our imaging marker of plasticity. The proportion of patients with gadolinium-enhancing lesions reduced significantly during IFN beta. In session 1, patients demonstrated a greater between-run difference in functional MRI activity of secondary visual areas and cerebellum than controls. This abnormally large practice-induced signal change in visual areas, and in functionally connected posterior parietal and motor cortices, was reduced in patients in session 3 compared with 2. Our results suggest that MS inflammation alters short-term plasticity underlying motor practice. Reduction of inflammation with IFN beta is associated with a restoration of this plasticity, suggesting that modulation of inflammation may enhance recovery-oriented strategies that rely on patients' brain plasticity. Hum Brain Mapp 37:2431-2445, 2016. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

Plastic-Film Mulching for Enhanced Water-Use Efficiency and Economic Returns from Maize Fields in Semiarid China

PubMed Central

Zhang, Peng; Wei, Ting; Cai, Tie; Ali, Shahzad; Han, Qingfang; Ren, Xiaolong; Jia, Zhikuan

2017-01-01

Film mulch has gradually been popularized to increase water availability to crops for improving and stabilizing agricultural production in the semiarid areas of Northwest China. To find more sustainable and economic film mulch methods for alleviating drought stress in semiarid region, it is necessary to test optimum planting methods in same cultivation conditions. A field experiment was conducted during 2013 and 2014 to evaluate the effects of different plastic film mulch methods on soil water, soil temperature, water use efficiency (WUE), yield and revenue. The treatments included: (i) the control, conventional flat planting without plastic film mulch (CK); (ii) flat planting with maize rows (60 cm spacing) on plastic film mulch (70 cm wide); (iii) furrow planting of maize (60 cm spacing), separated by consecutive plastic film-mulched ridges (each 50 cm wide and 15 cm tall); (iv) furrow planting of maize (60 cm spacing), separated by alternating large and small plastic film-mulched ridges (large ridges: 70 cm wide and 15 cm tall, small ridges 50 cm wide and 10 cm tall); and (v) furrow-flat planting of maize (60 cm spacing) with a large plastic film-mulched ridge (60 cm wide and 15 cm tall) alternating with a flat without plastic film-mulched space (60 cm wide). Topsoil temperature (5–25 cm) was significantly (p < 0.05) higher in field plots with plastic film mulch than the control (CK), and resulted in greater soil water storage (0–200 cm) up to 40 days after planting. Maize grain yield and WUE were significantly (p < 0.05) higher with the furrow planting methods (consecutive film-mulched ridges and alternating film-mulched ridges) than the check in both years. Maize yield was, on average, 29% (p < 0.05) greater and 28% (p < 0.05) greater with these furrow planting methods, while the average WUE increased by 22.8% (p < 0.05) with consecutive film-mulched ridges and 21.1% (p < 0.05) with alternating film-mulched ridges. The 2-year average net income increased by 1559, 528, and 350 Chinese Yuan (CNY) ha−1 with the consecutive film-mulched ridges, furrow-flat planting and alternating film-mulched ridges, respectively, compared with the control (CK). We conclude that the consecutive film-mulched ridge method was the most productive and profitable for maize in this semi-arid area with limited and erratic precipitation. PMID:28428798

Method for formation of thin film transistors on plastic substrates

DOEpatents

Carey, P.G.; Smith, P.M.; Sigmon, T.W.; Aceves, R.C.

1998-10-06

A process for formation of thin film transistors (TFTs) on plastic substrates replaces standard thin film transistor fabrication techniques, and uses sufficiently lower processing temperatures so that inexpensive plastic substrates may be used in place of standard glass, quartz, and silicon wafer-based substrates. The process relies on techniques for depositing semiconductors, dielectrics, and metals at low temperatures; crystallizing and doping semiconductor layers in the TFT with a pulsed energy source; and creating top-gate self-aligned as well as back-gate TFT structures. The process enables the fabrication of amorphous and polycrystalline channel silicon TFTs at temperatures sufficiently low to prevent damage to plastic substrates. The process has use in large area low cost electronics, such as flat panel displays and portable electronics. 5 figs.

49 CFR 178.925 - Standards for rigid plastic Large Packagings.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 49 Transportation 3 2011-10-01 2011-10-01 false Standards for rigid plastic Large Packagings. 178... FOR PACKAGINGS Large Packagings Standards § 178.925 Standards for rigid plastic Large Packagings. (a) The provisions in this section apply to rigid plastic Large Packagings intended to contain liquids and...

49 CFR 178.925 - Standards for rigid plastic Large Packagings.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 49 Transportation 3 2012-10-01 2012-10-01 false Standards for rigid plastic Large Packagings. 178... FOR PACKAGINGS Large Packagings Standards § 178.925 Standards for rigid plastic Large Packagings. (a) The provisions in this section apply to rigid plastic Large Packagings intended to contain liquids and...

49 CFR 178.925 - Standards for rigid plastic Large Packagings.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 49 Transportation 3 2014-10-01 2014-10-01 false Standards for rigid plastic Large Packagings. 178... FOR PACKAGINGS Large Packagings Standards § 178.925 Standards for rigid plastic Large Packagings. (a) The provisions in this section apply to rigid plastic Large Packagings intended to contain liquids and...

49 CFR 178.925 - Standards for rigid plastic Large Packagings.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 49 Transportation 3 2013-10-01 2013-10-01 false Standards for rigid plastic Large Packagings. 178... FOR PACKAGINGS Large Packagings Standards § 178.925 Standards for rigid plastic Large Packagings. (a) The provisions in this section apply to rigid plastic Large Packagings intended to contain liquids and...

PLASTIC SHRINKAGE CONTROLLING EFFECT BY POLYPROPYLENE SHORT FIBER WITH HYDROPHILY

NASA Astrophysics Data System (ADS)

Hosoda, Akira; Sadatsuki, Yoshitomo; Oshima, Akihiro; Ishii, Akina; Tsubaki, Tatsuya

The aim of this research is to clarify the mechanism of controlling plastic shrinkage crack by adding small amout of synthetic short fiber, and to propose optimum polypropylene short fiber to control plastic shrinkage crack. In this research, the effect of the hydrophily of polypropylene fiber was investigated in the amount of plastic shrinkage of mortar, total area of plastic shrinkage crack, and bond properties between fiber and mortar. The plastic shrinkage test of morar was conducted under high temperature, low relative humidity, and constant wind velocity. When polypropylene fiber had hydrophily, the amount of plastic shrinkage of mortar was restrained, which was because cement paste in morar was captured by hydrophilic fiber and then bleeding of mortar was restrained. With hydrophily, plastic shrinkage of mortar was restrained and bridging effect was improved due to better bond, which led to remarkable reduction of plastic shrinkage crack. Based on experimental results, the way of developing optimum polypropylene short fiber for actual construction was proposed. The fiber should have large hydrophily and small diameter, and should be used in as small amount as possible in order not to disturb workability of concrete.

Elevated temperature is more effective than elevated [CO2 ] in exposing genotypic variation in Telopea speciosissima growth plasticity: implications for woody plant populations under climate change.

PubMed

Huang, Guomin; Rymer, Paul D; Duan, Honglang; Smith, Renee A; Tissue, David T

2015-10-01

Intraspecific variation in phenotypic plasticity is a critical determinant of plant species capacity to cope with climate change. A long-standing hypothesis states that greater levels of environmental variability will select for genotypes with greater phenotypic plasticity. However, few studies have examined how genotypes of woody species originating from contrasting environments respond to multiple climate change factors. Here, we investigated the main and interactive effects of elevated [CO2 ] (CE ) and elevated temperature (TE ) on growth and physiology of Coastal (warmer, less variable temperature environment) and Upland (cooler, more variable temperature environment) genotypes of an Australian woody species Telopea speciosissima. Both genotypes were positively responsive to CE (35% and 29% increase in whole-plant dry mass and leaf area, respectively), but only the Coastal genotype exhibited positive growth responses to TE . We found that the Coastal genotype exhibited greater growth response to TE (47% and 85% increase in whole-plant dry mass and leaf area, respectively) when compared with the Upland genotype (no change in dry mass or leaf area). No intraspecific variation in physiological plasticity was detected under CE or TE , and the interactive effects of CE and TE on intraspecific variation in phenotypic plasticity were also largely absent. Overall, TE was a more effective climate factor than CE in exposing genotypic variation in our woody species. Our results contradict the paradigm that genotypes from more variable climates will exhibit greater phenotypic plasticity in future climate regimes. © 2015 John Wiley & Sons Ltd.

Learning to Encode Timing: Mechanisms of Plasticity in the Auditory Brainstem

PubMed Central

Tzounopoulos, Thanos; Kraus, Nina

2009-01-01

Mechanisms of plasticity have traditionally been ascribed to higher-order sensory processing areas such as the cortex, whereas early sensory processing centers have been considered largely hard-wired. In agreement with this view, the auditory brainstem has been viewed as a nonplastic site, important for preserving temporal information and minimizing transmission delays. However, recent groundbreaking results from animal models and human studies have revealed remarkable evidence for cellular and behavioral mechanisms for learning and memory in the auditory brainstem. PMID:19477149

Incidence of plastic fragments among burrow-nesting seabird colonies on offshore islands in northern New Zealand.

PubMed

Buxton, Rachel T; Currey, Caitlin A; Lyver, Philip O'B; Jones, Christopher J

2013-09-15

Marine plastic pollution is ubiquitous throughout the world's oceans, and has been found in high concentrations in oceanic gyres of both the northern and southern hemispheres. The number of studies demonstrating plastic debris at seabird colonies and plastic ingestion by adult seabirds has increased over the past few decades. Despite the recent discovery of a large aggregation of plastic debris in the South Pacific subtropical gyre, the incidence of plastics at seabird colonies in New Zealand is unknown. Between 2011 and 2012 we surveyed six offshore islands on the northeast coast of New Zealand's North Island for burrow-nesting seabird colonies and the presence of plastic fragments. We found non-research related plastic fragments (0.031 pieces/m(2)) on one island only, Ohinau, within dense flesh-footed shearwater (Puffinus carneipes) colonies. On Ohinau, we found a linear relationship between burrow density and plastic density, with 3.5 times more breeding burrows in areas with plastic fragments found. From these data we conclude that plastic ingestion is a potentially a serious issue for flesh-footed shearwaters in New Zealand. Although these results do not rule out plastic ingestion by other species, they suggest the need for further research on the relationship between New Zealand's pelagic seabirds and marine plastic pollution. Copyright © 2013 Elsevier Ltd. All rights reserved.

Threat of plastic pollution to seabirds is global, pervasive, and increasing.

PubMed

Wilcox, Chris; Van Sebille, Erik; Hardesty, Britta Denise

2015-09-22

Plastic pollution in the ocean is a global concern; concentrations reach 580,000 pieces per km(2) and production is increasing exponentially. Although a large number of empirical studies provide emerging evidence of impacts to wildlife, there has been little systematic assessment of risk. We performed a spatial risk analysis using predicted debris distributions and ranges for 186 seabird species to model debris exposure. We adjusted the model using published data on plastic ingestion by seabirds. Eighty of 135 (59%) species with studies reported in the literature between 1962 and 2012 had ingested plastic, and, within those studies, on average 29% of individuals had plastic in their gut. Standardizing the data for time and species, we estimate the ingestion rate would reach 90% of individuals if these studies were conducted today. Using these results from the literature, we tuned our risk model and were able to capture 71% of the variation in plastic ingestion based on a model including exposure, time, study method, and body size. We used this tuned model to predict risk across seabird species at the global scale. The highest area of expected impact occurs at the Southern Ocean boundary in the Tasman Sea between Australia and New Zealand, which contrasts with previous work identifying this area as having low anthropogenic pressures and concentrations of marine debris. We predict that plastics ingestion is increasing in seabirds, that it will reach 99% of all species by 2050, and that effective waste management can reduce this threat.

Threat of plastic pollution to seabirds is global, pervasive, and increasing

PubMed Central

Wilcox, Chris; Van Sebille, Erik; Hardesty, Britta Denise

2015-01-01

Plastic pollution in the ocean is a global concern; concentrations reach 580,000 pieces per km2 and production is increasing exponentially. Although a large number of empirical studies provide emerging evidence of impacts to wildlife, there has been little systematic assessment of risk. We performed a spatial risk analysis using predicted debris distributions and ranges for 186 seabird species to model debris exposure. We adjusted the model using published data on plastic ingestion by seabirds. Eighty of 135 (59%) species with studies reported in the literature between 1962 and 2012 had ingested plastic, and, within those studies, on average 29% of individuals had plastic in their gut. Standardizing the data for time and species, we estimate the ingestion rate would reach 90% of individuals if these studies were conducted today. Using these results from the literature, we tuned our risk model and were able to capture 71% of the variation in plastic ingestion based on a model including exposure, time, study method, and body size. We used this tuned model to predict risk across seabird species at the global scale. The highest area of expected impact occurs at the Southern Ocean boundary in the Tasman Sea between Australia and New Zealand, which contrasts with previous work identifying this area as having low anthropogenic pressures and concentrations of marine debris. We predict that plastics ingestion is increasing in seabirds, that it will reach 99% of all species by 2050, and that effective waste management can reduce this threat. PMID:26324886

Understanding Microplastic Distribution: A Global Citizen Monitoring Effort

NASA Astrophysics Data System (ADS)

Barrows, A.

2016-02-01

Understanding distribution and abundance of microplastics in the world's oceans will continue to help inform global law-making. Through recruiting and training over 500 volunteers our study has collected over 1000 samples from remote and populated areas world-wide. Samples include water collected at the sea surface and throughout the water column. Surface to depth sampling has provided insight into vertical plastic distribution. The development of unique field and laboratory methodology has enabled plastics to be quantified down to 50 µm. In 2015, the study expanded to include global freshwater systems. By understanding plastic patterns, distribution and concentration in large and small watersheds we will better understand how freshwater systems are contributing to marine microplastic pollution.

AM OLED using a-Si TFT backplane on flexible plastic substrate

NASA Astrophysics Data System (ADS)

Sarma, Kalluri R.; Schmidt, John; Roush, Jerry; Chanley, Charles; Dodd, Sonia R.

2004-09-01

Amorphous silicon TFT technology continues to show promise for fabricating large area high resolution flexible AM OLED displays. This paper describes the recent progress in the flexible AM OLED development efforts at Honeywell since our publication in this conference's proceedings in 2003, describing the feasibility of fabricating a 64x64 pixel AM OLED on a flexible plastic substrate. In this paper we describe the design, and fabrication of a 160x160(x3) pixel AM OLED on a flexible plastic substrate with an equivalent 80cgpi resolution. Flexibility characteristics of the fabricated displays are discussed. Further advances and improvements required for extending the size and resolution of flexible AM OLED displays are discussed.

Soil properties of crocker formation and its influence on slope instability along the Ranau-Tambunan highway, Sabah

NASA Astrophysics Data System (ADS)

Azlan, Noran Nabilla Nor; Simon, Norbert; Hussin, Azimah; Roslee, Rodeano

2016-11-01

The Crocker formation on the study area consists of an inter-bedded shale and sandstone. The intense deformation and discontinuity on sandstone and shale beds of the arenaceous Crocker Formation makes them easily exposed to weathering and instability. In this study, a total of 15 selected slopes representing highly weathered material of stable and unstable conditions were studied to identify the characteristics of soil material on both conditions and how these characteristics will lead to instability. Physical properties analysis of soil material were conducted on 5 samples from stable slopes and 10 samples from failed slopes collected along the Ranau-Tambunan highway (RTM), Sabah. The analysis shows that the Crocker Formation consists mainly of poorly graded materials of sandy SILT with low plasticity (MLS) and PI value ranges from 1%-14. The failures materials are largely consist of low water content (0.94%-2.03%), higher finer texture material (11%-71%), intermediate liquid limit (21%-44%) and low plastic limit (20%-30%) while stable material consist of low water content (1.25%-1.80%), higher coarser texture material (43%-78%), low liquid limit (25%-28%) and low plastic limit (22%-25%). Specific gravity shows a ranges value of 2.24-2.60 for both slope conditions. The clay content in failed slope samples exhibit a slightly higher percentage of clay indicating a higher plasticity value compared to stable slopes. Statistical analysis was carried out to examine the association between landslide occurrences with soil physical properties in both stable and unstable slopes. The significant of both slope condition properties association to landslide occurrences was determined by mean rank differences. The study reveals that the grain size and plasticity of soil have contributed largely to slope instability in the study area.

Large Volume, Behaviorally-relevant Illumination for Optogenetics in Non-human Primates.

PubMed

Acker, Leah C; Pino, Erica N; Boyden, Edward S; Desimone, Robert

2017-10-03

This protocol describes a large-volume illuminator, which was developed for optogenetic manipulations in the non-human primate brain. The illuminator is a modified plastic optical fiber with etched tip, such that the light emitting surface area is > 100x that of a conventional fiber. In addition to describing the construction of the large-volume illuminator, this protocol details the quality-control calibration used to ensure even light distribution. Further, this protocol describes techniques for inserting and removing the large volume illuminator. Both superficial and deep structures may be illuminated. This large volume illuminator does not need to be physically coupled to an electrode, and because the illuminator is made of plastic, not glass, it will simply bend in circumstances when traditional optical fibers would shatter. Because this illuminator delivers light over behaviorally-relevant tissue volumes (≈ 10 mm 3 ) with no greater penetration damage than a conventional optical fiber, it facilitates behavioral studies using optogenetics in non-human primates.

Methacrylate based cross-linkers for improved thermomechanical properties and retention of radiation detection response in plastic scintillators

NASA Astrophysics Data System (ADS)

Mahl, Adam; Lim, Allison; Latta, Joseph; Yemam, Henok A.; Greife, Uwe; Sellinger, Alan

2018-03-01

Pulse shape discrimination (PSD) is an important method that can efficiently sort and separate neutron and gamma radiation signals. PSD is currently achieved in plastic scintillators by over-doping poly(vinyl toluene) (PVT) matrices with fluorescent molecules. Meaningful separation of the signals requires addition of >20 wt% 2,5-diphenyloxazole (PPO) fluor in PVT. At these concentrations PPO acts as a plasticizer, negatively affecting the physical properties of the final plastic such as hardness, machinability, and thermomechanical stability. This work addresses these issues by implementing a cost-effective solution using cross-linking chemistry via commercially available bisphenol A dimethacrylate (BPA-DM), and a synthesized fluorinated analogue. Both improve the physical properties of over-doped PPO based plastic scintillators without degrading the measured light yield or PSD and Figure of Merit (FoM). In addition, the fluorinated analogue appears to enhance the hydrophobicity of the surface of the plastic scintillators, which may improve the scintillators' resistance to water diffusion and subsequent radiation response degradation. The new formulations improve the feasibility of widely deploying long lifetime PSD capable plastic scintillators in large area coverage assemblies.

Phase diagram of two-dimensional hard ellipses.

PubMed

Bautista-Carbajal, Gustavo; Odriozola, Gerardo

2014-05-28

We report the phase diagram of two-dimensional hard ellipses as obtained from replica exchange Monte Carlo simulations. The replica exchange is implemented by expanding the isobaric ensemble in pressure. The phase diagram shows four regions: isotropic, nematic, plastic, and solid (letting aside the hexatic phase at the isotropic-plastic two-step transition [E. P. Bernard and W. Krauth, Phys. Rev. Lett. 107, 155704 (2011)]). At low anisotropies, the isotropic fluid turns into a plastic phase which in turn yields a solid for increasing pressure (area fraction). Intermediate anisotropies lead to a single first order transition (isotropic-solid). Finally, large anisotropies yield an isotropic-nematic transition at low pressures and a high-pressure nematic-solid transition. We obtain continuous isotropic-nematic transitions. For the transitions involving quasi-long-range positional ordering, i.e., isotropic-plastic, isotropic-solid, and nematic-solid, we observe bimodal probability density functions. This supports first order transition scenarios.

The Use of Miniature Electret Microphones in Small Optoacoustic Cells.

DTIC Science & Technology

1980-06-30

conductivity. The work-horse material has been carnauba wax (used in floor polishes), but shellac, sealing wax , and naphthalene have been used. Such...electret is normally short with large area working faces. * The typical electret material is an organic wax or plastic, a material of poor electrical

KSC-04pd1894

NASA Image and Video Library

2004-09-22

KENNEDY SPACE CENTER, FLA. - Large pieces of equipment in the Processing Control Center in the Launch Complex 39 Area are covered in plastic in preparation for the arrival of Hurricane Jeanne, expected to impact Central Florida Sunday. This is the fourth hurricane in 45 days to make landfall somewhere in the state.

[Application of biodegradable plastic film to reduce plastic film residual pollution in Chinese agriculture].

PubMed

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.

Microstructured plastic optical fibers for applications in FTTH systems

NASA Astrophysics Data System (ADS)

Welikow, K.; Gdula, P.; Szczepański, P.; Buczyński, R.; Piramidowicz, R.

2012-04-01

This work is focused on the selected aspects of designing of microstructured POF (mPOF) with relatively large core, limited modal dispersion and improved resistance to bending losses, discussed in the context of its possible application in FTTH systems. The calculations confirmed the possibility of effective controlling both, the propagation and macrobending losses, as well as manipulation on the number of modes and modal area. The careful theoretical analysis allowed to design a series of geometries supporting the propagation of limited number of modes and, simultaneously, relatively large mode area together with limited bending losses.

Nanotechnology and regenerative therapeutics in plastic surgery: The next frontier

PubMed Central

Tan, Aaron; Chawla, Reema; Natasha, G; Mahdibeiraghdar, Sara; Jeyaraj, Rebecca; Rajadas, Jayakumar; Hamblin, Michael R.; Seifalian, Alexander M.

2015-01-01

Summary The rapid ascent of nanotechnology and regenerative therapeutics as applied to medicine and surgery has seen an exponential rise in the scale of research generated in this field. This is evidenced not only by the sheer volume of papers dedicated to nanotechnology but also in a large number of new journals dedicated to nanotechnology and regenerative therapeutics specifically to medicine and surgery. Aspects of nanotechnology that have already brought benefits to these areas include advanced drug delivery platforms, molecular imaging and materials engineering for surgical implants. Particular areas of interest include nerve regeneration, burns and wound care, artificial skin with nanoelectronic sensors and head and neck surgery. This study presents a review of nanotechnology and regenerative therapeutics, with focus on its applications and implications in plastic surgery. PMID:26422652

Field evaluation of ZeroFly--an insecticide incorporated plastic sheeting against malaria vectors & its impact on malaria transmission in tribal area of northern Orissa.

PubMed

Sharma, S K; Upadhyay, A K; Haque, M A; Tyagi, P K; Mohanty, S S; Mittal, P K; Dash, A P

2009-10-01

Insecticide incorporated plastic sheeting is a new technology to control mosquitoes in emergency shelter places and also temporary habitations in different locations. Therefore, field studies were conducted to assess the efficacy of ZeroFly plastic sheeting treated with deltamethrin on prevailing disease vectors Anopheles culicifacies and An. fluviatilis and its impact on malaria transmission in one of the highly endemic areas of Orissa. The study was conducted in Birkera block of Sundargarh district, Orissa state. The study area comprised 3 villages, which were randomized as ZeroFly plastic sheet, untreated plastic sheet and no sheet area. ZeroFly plastic sheets and untreated plastic sheets were fixed in study and control villages respectively covering all the rooms in each household. Longitudinal studies were conducted on the bioefficacy with the help of cone bioassays, monitoring of the mosquito density through hand catch, floor sheet and exit trap collections and fortnightly domiciliary active surveillance in all the study villages. In ZeroFly plastic sheeting area, there was a significant reduction of 84.7 per cent in the entry rate of total mosquitoes in comparison to pre-intervention phase. There was 56.2 per cent immediate mortality in total mosquitoes in houses with ZeroFly sheeting. The overall feeding success rate of mosquitoes in the trial village was only 12.5 per cent in comparison to 49.7 and 51.1 per cent in villages with untreated plastic sheet and no sheet respectively. There was a significant reduction of 65.0 and 70.5 per cent in malaria incidence in ZeroFly plastic sheeting area as compared to untreated plastic sheet and no sheet area respectively. Our study showed that introduction of ZeroFly plastic sheets in a community-based intervention programme is operationally feasible to contain malaria especially in the high transmission difficult areas.

Plastic and Large-Deflection Analysis of Nonlinear Structures

NASA Technical Reports Server (NTRS)

Thomson, R. G.; Hayduk, R. J.; Robinson, M. P.; Durling, B. J.; Pifko, A.; Levine, H. S.; Armen, H. J.; Levy, A.; Ogilvie, P.

1982-01-01

Plastic and Large Deflection Analysis of Nonlinear Structures (PLANS) system is collection of five computer programs for finite-element static-plastic and large deflection analysis of variety of nonlinear structures. System considers bending and membrane stresses, general three-dimensional bodies, and laminated composites.

Recycling in a megacity.

PubMed

Themelis, Nickolas J; Todd, Claire E

2004-04-01

In the aftermath of the 9/11 disaster, Mayor Bloomberg of New York City unveiled an aggressive budget plan that included the temporary suspension of glass and plastics recycling. This was considered by many to be anti-environmental, but the results of this study show that for lack of markets, even at zero or negative prices, nearly 90% of the plastic and glass set aside by thoughtful New Yorkers was transported to materials recovery facilities (MRFs) and from there to landfills. Sending bales of plastics to landfills is not limited to New York City. It is an environmental paradox that the United States is digging up new oil fields in pristine areas and, at the same time, continues to convert greenfields to brownfields by burying nearly 20 million tons of plastic fuel annually. The study also determined that at the present rate of source separation, estimated to be less than 30% of the available recyclables in 1999, building large, modern MRFs may increase substantially the rate of New York City recycling and also allow single-stream collection of commingled recyclables, as is done in Phoenix, AZ. Single-stream collection simplifies separation at the source by citizens and increases the amount of collected recyclables. Also, because collection represents a large fraction of the costs of waste management, it may have a significant economic advantage.

Microstructural examination of

NASA Astrophysics Data System (ADS)

Fukuoka, C.; Yoshizawa, H.; Nakagawa, Y. G.; Lapides, M. E.

1993-10-01

Fatigue tests were performed to examine how microstructural conditioning influences crack initiation and propagation in SA508 class 3 low-carbon steel. A 3-mm-long crack was introduced in compact tension (CT) fatigue test specimens under four different loads in order to obtain crack tip plastic zones at different stress intensity factor ranges, ΔK = 18, 36, 54, and 72 MPa√m. The microstructure of the plastic zones around the crack tip were examined by trans- mission electron microscopy (TEM) and selected area electron diffraction (SAD). Micro- orientation of the dislocation cells in the plastic zones of all of the CT samples increased to 4 deg from the level of an as-received sample. Four-point bending fatigue tests were performed for plate shape samples with a large cyclic strain range. The SAD value of the bending samples was also 4 deg in the damaged area where cracks already initiated at an early stage of the fatigue process. These test results indicate that the microstructural conditioning is a prerequisite for the fatigue crack initiation and propagation in SA508. These observations may lead to better under- standing of how fatigue initiation processes transit to cracks.

Fabrication Techniques for Unusual Electronic Systems: Silicon Microstructures for Photovoltaic Modules

ERIC Educational Resources Information Center

Baca, Alfred

2009-01-01

Electronics that can cover large areas, often referred to as macroelectronics, has received increasing attention over the past decade mainly due to it use in display systems, but increasingly due to certain forms of macroelectronics that can be integrated with thin plastic sheets or elastomeric substrates to yield mechanically flexible and…

Inexpensive Dramatic Pneumatic Lift

ERIC Educational Resources Information Center

Morse, Robert A.

2017-01-01

Various experiments and demonstrations relate air pressure and air pressure difference to force and area. Carpenter and Minnix describe a large-scale pneumatic lift in which a person sitting on a board atop a plastic garbage bag is lifted when the bag is connected to the exhaustport of a vacuum cleaner, which easily lifts the person. This article…

75 FR 81480 - Approval and Promulgation of Air Quality Implementation Plans; Pennsylvania; Allegheny County's...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-12-28

... Allegheny County Health Department (ACHD) Rules and Regulations, Article XXI, Air Pollution Control, and... and prior to the area's date of attainment. CTGs are intended to provide State and local air pollution...; plastic asceptic packaging; and carbon paper and inked ribbons. VOC emissions from large appliance, metal...

Plasticity of orientation preference maps in the visual cortex of adult cats.

PubMed

Godde, Ben; Leonhardt, Ralph; Cords, Sven M; Dinse, Hubert R

2002-04-30

In contrast to the high degree of experience-dependent plasticity usually exhibited by cortical representational maps, a number of experiments performed in visual cortex suggest that the basic layout of orientation preference maps is only barely susceptible to activity-dependent modifications. In fact, most of what we know about activity-dependent plasticity in adults comes from experiments in somatosensory, auditory, or motor cortex. Applying a stimulation protocol that has been proven highly effective in other cortical areas, we demonstrate here that enforced synchronous cortical activity induces major changes of orientation preference maps (OPMs) in adult cats. Combining optical imaging of intrinsic signals and electrophysiological single-cell recordings, we show that a few hours of intracortical microstimulation (ICMS) lead to an enlargement of the cortical representational zone at the ICMS site and an extensive restructuring of the entire OPM layout up to several millimeters away, paralleled by dramatic changes of pinwheel numbers and locations. At the single-cell level, we found that the preferred orientation was shifted toward the orientation of the ICMS site over a region of up to 4 mm. Our results show that manipulating the synchronicity of cortical activity locally without invoking training, attention, or reinforcement, OPMs undergo large-scale reorganization reminiscent of plastic changes observed for nonvisual cortical maps. However, changes were much more widespread and enduring. Such large-scale restructuring of the visual cortical networks indicates a substantial capability for activity-dependent plasticity of adult visual cortex and may provide the basis for cognitive learning processes.

Combustion products of plastics as indicators for refuse burning in the atmosphere.

PubMed

Simoneit, Bernd R T; Medeiros, Patricia M; Didyk, Borys M

2005-09-15

Despite all of the economic problems and environmental discussions on the dangers and hazards of plastic materials, plastic production worldwide is growing at a rate of about 5% per year. Increasing techniques for recycling polymeric materials have been developed during the last few years; however, a large fraction of plastics are still being discarded in landfills or subjected to intentional or incidental open-fire burning. To identify specific tracer compounds generated during such open-fire combustion, both smoke particles from burning and plastic materials from shopping bags, roadside trash, and landfill garbage were extracted for gas chromatography-mass spectrometry analyses. Samples were collected in Concón, Chile, an area frequently affected by wildfire incidents and garbage burning, and the United States for comparison. Atmospheric samples from various aerosol sampling programs are also presented as supportive data. The major components of plastic extracts were even-carbon-chain n-alkanes (C16-C40), the plasticizer di-2-ethylhexyl phthalate, and the antioxidants and lubricants/antiadhesives Irganox 1076, Irgafos 168, and its oxidation product tris(2,4-di-tertbutylphenyl) phosphate. Major compounds in smoke from burning plastics include the non-source-specific n-alkanes (mainly even predominance), terephthalic acid, phthalates, and 4-hydroxybenzoic acid, with minor amounts of polycyclic aromatic hydrocarbons (including triphenylbenzenes) and tris(2,4-di-tert-butylphenyl)phosphate. 1,3,5-Triphenylbenzene and tris(2,4-di-tert-butylphenyl)- phosphate were found in detectable amounts in atmospheric samples where plastics and refuse were burned in open fires, and thus we propose these two compounds as specific tracers for the open-burning of plastics.

Twenty years of experience with particulate silicone in plastic surgery.

PubMed

Planas, J; del Cacho, C

1992-01-01

The use of particulate silicone in plastic surgery involves the introduction of solid silicone into the body. The silicone is in small pieces in order for it to adapt to the shape of the defect. This way large quantities can be introduced through small incisions. It is also possible to distribute the silicone particles from outside the skin to make the corrections more regular. This method has been very useful for correcting post-traumatic depressions in the face and all areas where the depression has a rigid back support. We consider it the treatment of choice for correcting the funnel chest deformity.

GaAs photovoltaics and optoelectronics using releasable multilayer epitaxial assemblies.

PubMed

Yoon, Jongseung; Jo, Sungjin; Chun, Ik Su; Jung, Inhwa; Kim, Hoon-Sik; Meitl, Matthew; Menard, Etienne; Li, Xiuling; Coleman, James J; Paik, Ungyu; Rogers, John A

2010-05-20

Compound semiconductors like gallium arsenide (GaAs) provide advantages over silicon for many applications, owing to their direct bandgaps and high electron mobilities. Examples range from efficient photovoltaic devices to radio-frequency electronics and most forms of optoelectronics. However, growing large, high quality wafers of these materials, and intimately integrating them on silicon or amorphous substrates (such as glass or plastic) is expensive, which restricts their use. Here we describe materials and fabrication concepts that address many of these challenges, through the use of films of GaAs or AlGaAs grown in thick, multilayer epitaxial assemblies, then separated from each other and distributed on foreign substrates by printing. This method yields large quantities of high quality semiconductor material capable of device integration in large area formats, in a manner that also allows the wafer to be reused for additional growths. We demonstrate some capabilities of this approach with three different applications: GaAs-based metal semiconductor field effect transistors and logic gates on plates of glass, near-infrared imaging devices on wafers of silicon, and photovoltaic modules on sheets of plastic. These results illustrate the implementation of compound semiconductors such as GaAs in applications whose cost structures, formats, area coverages or modes of use are incompatible with conventional growth or integration strategies.

Utilization of wavelength-shifting fibers coupled to ZnS(Ag) and plastic scintillator for simultaneous detection of alpha/beta particles

NASA Astrophysics Data System (ADS)

Ifergan, Y.; Dadon, S.; Israelashvili, I.; Osovizky, A.; Gonen, E.; Yehuda-Zada, Y.; Smadja, D.; Knafo, Y.; Ginzburg, D.; Kadmon, Y.; Cohen, Y.; Mazor, T.

2015-06-01

Low level radioactive surface contamination measurements require lightweight, large area and high efficiency detector. In most existing scintillation detectors there is a tradeoff between effective area and scintillation light collection. By using wavelength shifting (WLS) fibers the scintillation light may be collected efficiently also in a large area detector. In this study, WLS fibers were coupled to a beta sensitive plastic scintillator layer and to a alpha sensitive silver-activated zinc sulfide ZnS(Ag) layer for detecting both alpha and beta particles. The WLS fibers collect the scintillation light from the whole detector and transfer it to a single PMT. This first prototype unique configuration enables monitoring radioactive contaminated surfaces by both sides of the detector and provides high gamma rejection. In this paper, the detector structure, as well as the detector's measured linear response, will be described. The measured detection efficiency of 238Pu alpha particles (5.5 MeV) is 63%. The measured detection efficiency for beta particles is 89% for 90Sr-90Y (average energy of 195.8 keV, 934.8 keV), 50% for 36Cl (average energy of 251.3 keV), and 35% for 137Cs (average energy of 156.8 keV).

Comprehensive analysis of area-specific and time-dependent changes in gene expression in the motor cortex of macaque monkeys during recovery from spinal cord injury.

PubMed

Higo, Noriyuki; Sato, Akira; Yamamoto, Tatsuya; Oishi, Takao; Nishimura, Yukio; Murata, Yumi; Onoe, Hirotaka; Isa, Tadashi; Kojima, Toshio

2018-05-01

The present study aimed to assess the molecular bases of cortical compensatory mechanisms following spinal cord injury in primates. To accomplish this, comprehensive changes in gene expression were investigated in the bilateral primary motor cortex (M1), dorsal premotor cortex (PMd), and ventral premotor cortex (PMv) after a unilateral lesion of the lateral corticospinal tract (l-CST). At 2 weeks after the lesion, a large number of genes exhibited altered expression levels in the contralesional M1, which is directly linked to the lesioned l-CST. Gene ontology and network analyses indicated that these changes in gene expression are involved in the atrophy and plasticity changes observed in neurons. Orchestrated gene expression changes were present when behavioral recovery was attained 3 months after the lesion, particularly among the bilateral premotor areas, and a large number of these genes are involved in plasticity. Moreover, several genes abundantly expressed in M1 of intact monkeys were upregulated in both the PMd and PMv after the l-CST lesion. These area-specific and time-dependent changes in gene expression may underlie the molecular mechanisms of functional recovery following a lesion of the l-CST. © 2018 Wiley Periodicals, Inc.

GLASS FIBER REINFORCED PLASTICS,

DTIC Science & Technology

Contents: Fibrous glass fillers Binders used in the glass plastic industry Method of manufacturing glass plastics and glass plastic articles Properties of fiberglass Primary areas for use of glass fibre reinforced plastics

Very low temperature materials and self-alignment technology for amorphous hydrated silicon thin film transistors fabricated on transparent large area plastic substrates

NASA Astrophysics Data System (ADS)

Yang, Chien-Sheng

The purpose of this research has been to (1) explore materials prepared using plasma enhanced chemical vapor deposition (PECVD) at 110sp°C for amorphous silicon thin film transistors (TFT's) fabricated on low temperature compatible, large area flexible polyethylene terephthalate (PET) substrates, and (2) develop full self-alignment technology using selective area n+ PECVD for source/drain contacts of amorphous silicon TFT's. For item (1), silicon nitride films, as gate dielectrics of TFT's, were deposited using SiHsb4+NHsb3, SiHsb4+NHsb3+Nsb2, SiHsb4+NHsb3+He, or SiHsb4+NHsb3+Hsb2 gases. Good quality silicon nitride films can be deposited using a SiHsb4+NHsb3 gas with high NHsb3/SiHsb4 ratios, or using a SiHsb4+NHsb3+Nsb2 gas with moderate NHsb3/SiHsb4 ratios. A chemical model was proposed to explain the Nsb2 dilution effect. This model includes calculations of (a) the electron energy distribution function in a plasma, (b) rate constants of electron impact dissociation, and (3) the (NHsbx) / (SiHsby) ratio in a plasma. The Nsb2 dilution was shown to have a effect of shifting the electron energy distribution into high energy, thus enhancing the (NHsbx) / (SiHsbyrbrack ratio in a plasma and promoting the deposition of N-rich silicon nitride films, which leads to decreased trap state density and a shift in trap state density to deeper in the gap. Amorphous silicon were formed successfully at 110sp°C on large area glass and plastic(PET) substrates. Linear mobilities are 0.33 and 0.12 cmsp2/Vs for TFT's on glass and plastic substrates, respectively. ON/OFF current ratios exceed 10sp7 for TFT's on glass and 10sp6 for TFT's on PET. For item (2), a novel full self-alignment process was developed for amorphous silicon TFT's. This process includes (1) back-exposure using the bottom gate metal as the mask, and (2) selective area n+ micro-crystalline silicon PECVD for source/drain contacts of amorphous silicon TFT's. TFT's fabricated using the full self-alignment process showed linear mobilities ranging from 0.5 to 1.0 cmsp2/Vs.

Temporal sequence learning in winner-take-all networks of spiking neurons demonstrated in a brain-based device.

PubMed

McKinstry, Jeffrey L; Edelman, Gerald M

2013-01-01

Animal behavior often involves a temporally ordered sequence of actions learned from experience. Here we describe simulations of interconnected networks of spiking neurons that learn to generate patterns of activity in correct temporal order. The simulation consists of large-scale networks of thousands of excitatory and inhibitory neurons that exhibit short-term synaptic plasticity and spike-timing dependent synaptic plasticity. The neural architecture within each area is arranged to evoke winner-take-all (WTA) patterns of neural activity that persist for tens of milliseconds. In order to generate and switch between consecutive firing patterns in correct temporal order, a reentrant exchange of signals between these areas was necessary. To demonstrate the capacity of this arrangement, we used the simulation to train a brain-based device responding to visual input by autonomously generating temporal sequences of motor actions.

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

ERIC Educational Resources Information Center

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…

Leaf age dependent changes in within-canopy variation in leaf functional traits: a meta-analysis

PubMed Central

Niinemets, Ülo

2018-01-01

Within-canopy variation in leaf structural and photosynthetic characteristics is a major means by which whole canopy photosynthesis is maximized at given total canopy nitrogen. As key acclimatory modifications, leaf nitrogen content (NA) and photosynthetic capacity (AA) per unit area increase with increasing light availability in the canopy and these increases are associated with increases in leaf dry mass per unit area (MA) and/or nitrogen content per dry mass and/or allocation. However, leaf functional characteristics change with increasing leaf age during leaf development and aging, but the importance of these alterations for within-canopy trait gradients is unknown. I conducted a meta-analysis based on 71 canopies that were sampled at different time periods or, in evergreens, included measurements for different-aged leaves to understand how within-canopy variations in leaf traits (trait plasticity) depend on leaf age. The analysis demonstrated that in evergreen woody species, MA and NA plasticity decreased with increasing leaf age, but the change in AA plasticity was less suggesting a certain re-acclimation of AA to altered light. In deciduous woody species, MA and NA gradients in flush-type species increased during leaf development and were almost invariable through the rest of the season, while in continuously leaf-forming species, trait gradients increased constantly with increasing leaf age. In forbs, NA plasticity increased, while in grasses, NA plasticity decreased with increasing leaf age, reflecting life form differences in age-dependent changes in light availability and in nitrogen resorption for growth of generative organs. Although more work is needed to improve the coverage of age-dependent plasticity changes in some plant life forms, I argue that the age-dependent variation in trait plasticity uncovered in this study is large enough to warrant incorporation in simulations of canopy photosynthesis through the growing period. PMID:27033356

Protected areas in the Atlantic facing the hazards of micro-plastic pollution: first diagnosis of three islands in the Canary Current.

PubMed

Baztan, Juan; Carrasco, Ana; Chouinard, Omer; Cleaud, Muriel; Gabaldon, Jesús E; Huck, Thierry; Jaffrès, Lionel; Jorgensen, Bethany; Miguelez, Aquilino; Paillard, Christine; Vanderlinden, Jean-Paul

2014-03-15

Coastal zones and the biosphere as a whole show signs of cumulative degradation due to the use and disposal of plastics. To better understand the manifestation of plastic pollution in the Atlantic Ocean, we partnered with local communities to determine the concentrations of micro-plastics in 125 beaches on three islands in the Canary Current: Lanzarote, La Graciosa, and Fuerteventura. We found that, in spite of being located in highly-protected natural areas, all beaches in our study area are exceedingly vulnerable to micro-plastic pollution, with pollution levels reaching concentrations greater than 100 g of plastic in 1l of sediment. This paper contributes to ongoing efforts to develop solutions to plastic pollution by addressing the questions: (i) Where does this pollution come from?; (ii) How much plastic pollution is in the world's oceans and coastal zones?; (iii) What are the consequences for the biosphere?; and (iv) What are possible solutions? Copyright © 2014 Elsevier Ltd. All rights reserved.

Microstructural examination of fatigue crack tip in high strength steel

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fukuoka, C.; Yoshizawa, H.; Nakagawa, Y.G.

1993-10-01

Fatigue tests were performed to examine how microstructural conditioning influences crack initiation and propagation in SA508 class 3 low-carbon steel. A 3-mm-long crack was introduced in compact tension (CT) fatigue test specimens under four different loads in order to obtain crack tip plastic zones at different stress intensity factor ranges, [Delta]K = 18, 36, 54, and 72 MPa[radical]m. The microstructure of the plastic zones around the crack tip were examined by transmission electron microscopy (TEM) and selected area electron diffraction (SAD). Micro-orientation of the dislocation cells in the plastic zones of all of the CT samples increased to 4 degmore » from the level of an as-received sample. Four-point bending fatigue tests were performed for plate shape samples with a large cyclic strain range. The SAD value of the bending samples was also 4 deg in the damaged area where cracks already initiated at an early stage of the fatigue process. These test results indicate that the microstructural conditioning is a prerequisite for the fatigue crack initiation and propagation in SA508. These observations may lead to better understanding of how fatigue initiation processes transit to cracks.« less

Primary cosmic ray particles with Z greater than 35 /VVH particles/. [Very Very Heavy particle track measurement by balloons

NASA Technical Reports Server (NTRS)

Blanford, G. E., Jr.; Friedlander, M. W.; Hoppe, M.; Klarmann, J.; Walker, R. M.; Wefel, J. P.

1974-01-01

Large areas of nuclear emulsions and plastic detectors were exposed to the primary cosmic radiation during high-altitude balloon flights. From an analysis of 141 particle tracks recorded during a total exposure of 13,000,000 sq m-ster-sec, a charge spectrum of the VVH particles has been derived.

Plastic superconductor bearings any size-any shape: 77 K and up

NASA Technical Reports Server (NTRS)

Reick, Franklin G.

1991-01-01

'Friction free' bearings at 77 K or higher are possible using the high T(sub c) copper oxide ceramic superconductors. The conventional method for making such bearings is to use a sintered ceramic monolith. This puts great restraints on size, shape, and postforming machining. The material is hard and abrasive. It is possible to grind up ceramic superconductors and suspend the granules in a suitable matrix. Mechanical properties improve and are largely dependent on the binder. The Meissner effect is confined to individual grains containing electron vortices. Tracks, rails, levitation areas, and bearings can be made this way with conventional plastic molding and extruding machines or by painting. The parts are easily machined. The sacrifice is in bulk electrical conductivity. A percolating wick feed for LN2 is used to cool remote superconductors and large areas quite effectively. A hollow spheroid or cylinder of superconductor material is molded with the internal surfaces shielded by the Meissner effect. It can be thought of as the DC magnetic analog of the Faraday cage and the inside is the 'Meissner space'. It is selective. The AC fields are transmitted with minor attenuation. Particle size and distribution have a profound effect on final magnetic and electrical characteristics.

Large-area high-efficiency flexible PHOLED lighting panels

NASA Astrophysics Data System (ADS)

Pang, Huiqing; Mandlik, Prashant; Levermore, Peter A.; Silvernail, Jeff; Ma, Ruiqing; Brown, Julie J.

2012-09-01

Organic Light Emitting Diodes (OLEDs) provide various attractive features for next generation illumination systems, including high efficiency, low power, thin and flexible form factor. In this work, we incorporated phosphorescent emitters and demonstrated highly efficient white phosphorescent OLED (PHOLED) devices on flexible plastic substrates. The 0.94 cm2 small-area device has total thickness of approximately 0.25 mm and achieved 63 lm/W at 1,000 cd/m2 with CRI = 85 and CCT = 2920 K. We further designed and fabricated a 15 cm x 15 cm large-area flexible white OLED lighting panels, finished with a hybrid single-layer ultra-low permeability single layer barrier (SLB) encapsulation film. The flexible panel has an active area of 116.4 cm2, and achieved a power efficacy of 47 lm/W at 1,000 cd/m2 with CRI = 83 and CCT = 3470 K. The efficacy of the panel at 3,000 cd/m2 is 43 lm/W. The large-area flexible PHOLED lighting panel is to bring out enormous possibilities to the future general lighting applications.

Growth potential limits drought morphological plasticity in seedlings from six Eucalyptus provenances.

PubMed

Maseda, Pablo H; Fernández, Roberto J

2016-02-01

Water stress modifies plant above- vs belowground biomass allocation, i.e., morphological plasticity. It is known that all species and genotypes reduce their growth rate in response to stress, but in the case of water stress it is unclear whether the magnitude of such reduction is linked to the genotype's growth potential, and whether the reduction can be largely attributed to morphological adjustments such as plant allocation and leaf and root anatomy. We subjected seedlings of six seed sources, three from each of Eucalyptus camaldulensis (potentially fast growing) and E. globulus (inherently slow growing), to three experimental water regimes. Biomass, leaf area and root length were measured in a 6-month glasshouse experiment. We then performed functional growth analysis of relative growth rate (RGR), and aboveground (leaf area ratio (LAR), specific leaf area (SLA) and leaf mass ratio (LMR)) and belowground (root length ratio (RLR), specific root length (SRL) and root mass ratio (RMR)) morphological components. Total biomass, root biomass and leaf area were reduced for all Eucalyptus provenances according to drought intensity. All populations exhibited drought plasticity, while those of greater growth potential (RGRmax) had a larger reduction in growth (discounting the effect of size). A positive correlation was observed between drought sensitivity and RGRmax. Aboveground, drought reduced LAR and LMR; under severe drought a negative correlation was found between LMR and RGRmax. Belowground, drought reduced SRL but increased RMR, resulting in no change in RLR. Under severe drought, a negative correlation was found between RLR, SRL and RGRmax. Our evidence strongly supports the classic ecophysiological trade-off between growth potential and drought tolerance for woody seedlings. It also suggests that slow growers would have a low capacity to adjust their morphology. For shoots, this constraint on plasticity was best observed in partition (i.e., LMR) whereas for roots it was clearest in morphology/anatomy (i.e., SRL). Thus, a low RGRmax would limit plastic response to drought not only at the whole plant level but also at the organ and even the tissue level. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Long-term microplastic retention causes reduced body condition in the langoustine, Nephrops norvegicus.

PubMed

Welden, Natalie A C; Cowie, Phillip R

2016-11-01

Microplastic represents a rising proportion of marine litter and is widely distributed throughout a range of marine habitats. Correspondingly, the number of reports of species containing microplastics increases annually. Nephrops norvegicus in the Firth of Clyde have previously been shown to retain large aggregations of microplastic fibres. The potential for N. norvegicus to retain plastic over an extended time period increases the likelihood of any associated negative impacts to the individual. This study represents the longest observation of the impacts of microplastic retention in invertebrates. We exposed N. norvegicus to plastic over eight months to determine the impacts of extended exposure. Over this period we compared the feeding rate, body mass, and nutritional state of plastic-fed N. norvegicus to that of fed and starved control groups. Following the experimental period, the plastic-fed langoustine contained microplastic aggregations comparable to those of small individuals from the Clyde Sea Area. Comparisons between fed, unfed and plastic-fed individuals indicated a reduction in feeding rate, body mass, and metabolic rate as well as catabolism of stored lipids in plastic contaminated animals. We conclude that N. norvegicus exposed to high levels of environmental microplastic pollution may experience reduced nutrient availability. This can result in reduced population stability and may affect the viability of local fisheries. Copyright © 2016 Elsevier Ltd. All rights reserved.

Trait Values, Not Trait Plasticity, Best Explain Invasive Species' Performance in a Changing Environment

PubMed Central

Matzek, Virginia

2012-01-01

The question of why some introduced species become invasive and others do not is the central puzzle of invasion biology. Two of the principal explanations for this phenomenon concern functional traits: invasive species may have higher values of competitively advantageous traits than non-invasive species, or they may have greater phenotypic plasticity in traits that permits them to survive the colonization period and spread to a broad range of environments. Although there is a large body of evidence for superiority in particular traits among invasive plants, when compared to phylogenetically related non-invasive plants, it is less clear if invasive plants are more phenotypically plastic, and whether this plasticity confers a fitness advantage. In this study, I used a model group of 10 closely related Pinus species whose invader or non-invader status has been reliably characterized to test the relative contribution of high trait values and high trait plasticity to relative growth rate, a performance measure standing in as a proxy for fitness. When grown at higher nitrogen supply, invaders had a plastic RGR response, increasing their RGR to a much greater extent than non-invaders. However, invasive species did not exhibit significantly more phenotypic plasticity than non-invasive species for any of 17 functional traits, and trait plasticity indices were generally weakly correlated with RGR. Conversely, invasive species had higher values than non-invaders for 13 of the 17 traits, including higher leaf area ratio, photosynthetic capacity, photosynthetic nutrient-use efficiency, and nutrient uptake rates, and these traits were also strongly correlated with performance. I conclude that, in responding to higher N supply, superior trait values coupled with a moderate degree of trait variation explain invasive species' superior performance better than plasticity per se. PMID:23119098

Plastic litter in sediments from the coasts of south Tuscany (Tyrrhenian Sea).

PubMed

Cannas, Susanna; Fastelli, Paolo; Guerranti, Cristiana; Renzi, Monia

2017-06-15

This study estimated the total loads of plastic litter (macro-meso- and micro-plastics) in sediments from a wide stretch of marine and coastal environment of Tyrrhenian Sea. The prevailing category of debris was microplastic. The results obtained, in terms of average amount of microplastic per kilogram of dry sediment, are in agreement with data reported by various Authors internationally. The study area resulted to be uniform for plastic items levels. Particularly evident was the influence of a flood, occurred in November 2012 in Talamone, on sediments collected at the harbour of this locality: in this area, a difference in levels and quality of plastic debris, attributable to periods before and after the flood, was observed in sediments. In addition to focusing on the effect of this phenomenon, this study gives an important overview, for what concerns the presence of plastic litter, of a significant naturalistic area. Copyright © 2017 Elsevier Ltd. All rights reserved.

DynAMITe: a prototype large area CMOS APS for breast cancer diagnosis using x-ray diffraction measurements

NASA Astrophysics Data System (ADS)

Konstantinidis, A.; Anaxagoras, T.; Esposito, M.; Allinson, N.; Speller, R.

2012-03-01

X-ray diffraction studies are used to identify specific materials. Several laboratory-based x-ray diffraction studies were made for breast cancer diagnosis. Ideally a large area, low noise, linear and wide dynamic range digital x-ray detector is required to perform x-ray diffraction measurements. Recently, digital detectors based on Complementary Metal-Oxide- Semiconductor (CMOS) Active Pixel Sensor (APS) technology have been used in x-ray diffraction studies. Two APS detectors, namely Vanilla and Large Area Sensor (LAS), were developed by the Multidimensional Integrated Intelligent Imaging (MI-3) consortium to cover a range of scientific applications including x-ray diffraction. The MI-3 Plus consortium developed a novel large area APS, named as Dynamically Adjustable Medical Imaging Technology (DynAMITe), to combine the key characteristics of Vanilla and LAS with a number of extra features. The active area (12.8 × 13.1 cm2) of DynaMITe offers the ability of angle dispersive x-ray diffraction (ADXRD). The current study demonstrates the feasibility of using DynaMITe for breast cancer diagnosis by identifying six breast-equivalent plastics. Further work will be done to optimize the system in order to perform ADXRD for identification of suspicious areas of breast tissue following a conventional mammogram taken with the same sensor.

Oncoplastic Surgery

PubMed Central

Chatterjee, Abhishek; Dayicioglu, Deniz; Khakpour, Nazanin; Czerniecki, Brian J.

2017-01-01

Oncoplastic surgery is an evolving field in breast surgery combining the strengths of breast surgical oncology with plastic surgery. It provides the surgeon the ability to excise large areas of the breast in the oncologic resection without compromising, and possibly improving, its aesthetic appearance. The purpose of this review is to provide a guide that could help a breast surgeon excise breast cancer in most areas of the breast using 5 oncoplastic techniques. These techniques would be used depending primarily on the location of the cancer in the breast and also on the size of the tumor. PMID:28975837

Primary cosmic ray particles with z 35 (VVH particles). [very heavy particle detection by high altitude balloons

NASA Technical Reports Server (NTRS)

Blanford, G. E., Jr.; Friedlander, M. W.; Hoppe, M.; Klarmann, J.; Walker, R. M.; Wefel, J. P.

1972-01-01

Large areas of nuclear emulsions and plastic detectors were exposed to the primary cosmic radiation during high altitude balloon flights. From the analysis of 141 particle tracks recorded during a total exposure of 1.3 x 10 to the 7th power sq m ster.sec., a charge spectrum of the VVH particles has been derived.

Distribution of phthalate esters in agricultural soil with plastic film mulching in Shandong Peninsula, East China.

PubMed

Li, Kankan; Ma, Dong; Wu, Juan; Chai, Chao; Shi, Yanxi

2016-12-01

The content of phthalate esters (PAEs) was investigated in 36 vegetable fields with plastic film mulching in Shandong Peninsula, East China. Soils at depths of 0-10 cm, 10-20 cm, and 20-40 cm were collected, and 16 PAEs were analyzed by gas chromatography-mass spectrometry. PAEs were detected in all the analyzed samples. The total contents of the 16 PAEs (Σ 16 PAEs) ranged from 1.374 to 18.810 mg/kg, with an average of 6.470 mg/kg. Among the four areas of Shandong Peninsula, including Qingdao, Weihai, Weifang, and Yantai, the highest Σ 16 PAE in the soil was observed in Weifang district (9.786 mg/kg), which is famous for large-scale vegetable production. Despite the significant differences among the Σ 16 PAEs, the PAE compositions in soils with plastic film mulching in Shandong Peninsula were comparable. Diethyl phthalate (DEP), diisobutyl phthalate, and di(4-methyl-2-pentyl) phthalate were present in all the samples, whereas di-n-hexyl phthalate was detected only in Qingdao (∼1%) and dicyclohexyl phthalate was observed only in Weifang (5.7-8.2%) in low proportions. The ratios of dimethyl phthalate, DEP, and di-n-butyl phthalate, which exceeded allowable concentrations, were 63.9-100% at different soil depths, indicating high PAE pollution. The concentration of butyl benzyl phthalate detected only in Weifang exceeded the recommended allowable soil concentration. Overall, the high PAE content in the soil with plastic film mulching in Shandong Peninsula is an issue of concern because of the large amounts of plastic film used. Copyright © 2016 Elsevier Ltd. All rights reserved.

Preservation of samples for dissolved mercury

USGS Publications Warehouse

Hamlin, S.N.

1989-01-01

Water samples for dissolved mercury requires special treatment because of the high chemical mobility and volatility of this element. Widespread use of mercury and its compounds has provided many avenues for contamination of water. Two laboratory tests were done to determine the relative permeabilities of glass and plastic sample bottles to mercury vapor. Plastic containers were confirmed to be quite permeable to airborne mercury, glass containers were virtually impermeable. Methods of preservation include the use of various combinations of acids, oxidants, and complexing agents. The combination of nitric acid and potassium dichromate successfully preserved mercury in a large variety of concentrations and dissolved forms. Because this acid-oxidant preservative acts as a sink for airborne mercury and plastic containers are permeable to mercury vapor, glass bottles are preferred for sample collection. To maintain a healthy work environment and minimize the potential for contamination of water samples, mercury and its compounds are isolated from the atmosphere while in storage. Concurrently, a program to monitor environmental levels of mercury vapor in areas of potential contamination is needed to define the extent of mercury contamination and to assess the effectiveness of mercury clean-up procedures.Water samples for dissolved mercury require special treatment because of the high chemical mobility and volatility of this element. Widespread use of mercury and its compounds has provided many avenues for contamination of water. Two laboratory tests were done to determine the relative permeabilities of glass and plastic sample bottles to mercury vapor. Plastic containers were confirmed to be quite permeable to airborne mercury, glass containers were virtually impermeable. Methods of preservation include the use of various combinations of acids, oxidants, and complexing agents. The combination of nitric acid and potassium dichromate successfully preserved mercury in a large variety of concentrations and dissolved forms.

Rural plastic emissions into the largest mountain lake of the Eastern Carpathians.

PubMed

Mihai, Florin-Constantin

2018-05-01

The lack of proper waste collection systems leads to plastic pollution in rivers in proximity to rural communities. This environmental threat is more widespread among mountain communities which are prone to frequent flash floods during the warm season. This paper estimates the amounts of plastic bottles dumped into the Izvoru Muntelui lake by upstream rural communities. The plastic pollution dimension between seasonal floods which affected the Bistrita catchment area during 2005-2012 is examined. The floods dumped over 290 tonnes of plastic bottles into the lake. Various scenarios are tested in order to explain each amount of plastic waste collected by local authorities during sanitation activities. The results show that rural municipalities are responsible for 85.51% of total plastic bottles collected during 2005-2010. The source of plastic pollution is mainly local. The major floods of July 2008 and June 2010 collected most of the plastic bottles scattered across the Bistrita river catchment (56 villages) and dumped them into the lake. These comparisons validate the proposed method as a reliable tool in the assessment process of river plastic pollution, which may also be applied in other geographical areas. Tourism and leisure activities are also found to be responsible for plastic pollution in the study area. A new regional integrated waste management system should improve the waste collection services across rural municipalities at the county level when it is fully operational. This paper demonstrates that rural communities are significant contributors of plastics into water bodies.

Rural plastic emissions into the largest mountain lake of the Eastern Carpathians

PubMed Central

2018-01-01

The lack of proper waste collection systems leads to plastic pollution in rivers in proximity to rural communities. This environmental threat is more widespread among mountain communities which are prone to frequent flash floods during the warm season. This paper estimates the amounts of plastic bottles dumped into the Izvoru Muntelui lake by upstream rural communities. The plastic pollution dimension between seasonal floods which affected the Bistrita catchment area during 2005–2012 is examined. The floods dumped over 290 tonnes of plastic bottles into the lake. Various scenarios are tested in order to explain each amount of plastic waste collected by local authorities during sanitation activities. The results show that rural municipalities are responsible for 85.51% of total plastic bottles collected during 2005–2010. The source of plastic pollution is mainly local. The major floods of July 2008 and June 2010 collected most of the plastic bottles scattered across the Bistrita river catchment (56 villages) and dumped them into the lake. These comparisons validate the proposed method as a reliable tool in the assessment process of river plastic pollution, which may also be applied in other geographical areas. Tourism and leisure activities are also found to be responsible for plastic pollution in the study area. A new regional integrated waste management system should improve the waste collection services across rural municipalities at the county level when it is fully operational. This paper demonstrates that rural communities are significant contributors of plastics into water bodies. PMID:29892426

Distribution of surface plastic debris in the eastern Pacific Ocean from an 11-year data set.

PubMed

Law, Kara Lavender; Morét-Ferguson, Skye E; Goodwin, Deborah S; Zettler, Erik R; Deforce, Emelia; Kukulka, Tobias; Proskurowski, Giora

2014-05-06

We present an extensive survey of floating plastic debris in the eastern North and South Pacific Oceans from more than 2500 plankton net tows conducted between 2001 and 2012. From these data we defined an accumulation zone (25 to 41 °N, 130 to 180 °W) in the North Pacific subtropical gyre that closely corresponds to centers of accumulation resulting from the convergence of ocean surface currents predicted by several oceanographic numerical models. Maximum plastic concentrations from individual surface net tows exceeded 10(6) pieces km(-2), with concentrations decreasing with increasing distance from the predicted center of accumulation. Outside the North Pacific subtropical gyre the median plastic concentration was 0 pieces km(-2). We were unable to detect a robust temporal trend in the data set, perhaps because of confounded spatial and temporal variability. Large spatiotemporal variability in plastic concentration causes order of magnitude differences in summary statistics calculated over short time periods or in limited geographic areas. Utilizing all available plankton net data collected in the eastern Pacific Ocean (17.4 °S to 61.0 °N; 85.0 to 180.0 °W) since 1999, we estimated a minimum of 21,290 t of floating microplastic.

Waste handling: A study of tributyl phosphate compatibility with nonmetallic materials

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jenkins, C.F.; Briedenbach, P.J.

1989-01-01

The need for numerous seals, plastic tubing, instrument components, and miles of plastic pipe for transferring process waste streams containing tributyl phosphate (TBP) and petroleum solvents led to an investigation of compatibility. TBP is a solvent for many plastics and elastomers and causes softening, crazing, or cracking of most nonmetallics tested. In this regard it may be considered an external plasticizer for some polymers. TBP also is a surfactant in aqueous solution. Dimension changes and property changes associated with softening will preclude the use of some materials as gaskets. Teflon/trademark/ and Kalrez/trademark/ gaskets appear to be compatible with TBP. Mixedmore » results were obtained with EPDM elastomers, but EPDM O-rings are less costly than Kalrez/trademark/ and are being applied in some areas. Exposure of CPVC rigid piping led to crazing and, ultimately, catastrophic stress cracking, thus precluding its use in the waste services described. High-density polyethylene and PVDF plastic piping were unaffected by the test exposures and are useable for process and process waste service. Applications include 25-30 miles of polyethylene pipe and a large number of EPDM gaskets in the filter assembly of an effluent treatment system at the Savannah River Plant. 3 refs., 7 figs., 3 tabs.« less

Contrasting Acute and Slow-Growing Lesions: A New Door to Brain Plasticity

ERIC Educational Resources Information Center

Desmurget, Michel; Bonnetblanc, FranCois; Duffau, Hugues

2007-01-01

The concept of plasticity describes the mechanisms that rearrange cerebral organization following a brain injury. During the last century, plasticity has been mainly investigated in humans with acute strokes. It was then shown: (i) that the brain is organized into highly specialized functional areas, often designated "eloquent" areas and (ii) that…

TRANSPORT PLANNING MODEL FOR WIDE AREA RECYCLING SYSTEM OF INDUSTRIAL WASTE PLASTIC

NASA Astrophysics Data System (ADS)

Arai, Yasuhiro; Kawamura, Hisashi; Koizumi, Akira; Mogi, Satoshi

To date, the majority of industrial waste plastic generated in an urban city has been processed into landfill. However, it is now necessary to actively utilize that plastic as a useful resource to create a recycling society with a low environment influence. In order to construct a reasonable recycling system, it is necessary to address the "transportation problem," which means determining how much industrial waste plastic is to be transported to what location. With the goal of eliminating landfill processing, this study considers a transport planning model for industrial waste plastic applying linear programming. The results of running optimized calculations under given scenarios clarified not only the possibilities for recycle processing in the Metropolitan area, but also the validity of wide area recycling system.

49 CFR 178.965 - Drop test.

Code of Federal Regulations, 2010 CFR

2010-10-01

...) Conditioning. Rigid plastic Large Packagings and Large Packagings with plastic inner receptacles must be... having essentially the same physical characteristics. (3) The specific gravity and viscosity of a...

Medical Student Perception of Plastic Surgery and the Impact of Mainstream Media

PubMed Central

Fraser, S. J.; Al Youha, S.; Rasmussen, P. J.

2017-01-01

Background: Plastic surgery as a discipline is poorly understood by many, including primary care physicians, nurses, medical students, and the public. These misconceptions affect the specialty in a number of ways, including referral patterns and recruitment of medical students into residency programs. The reason for these commonly held misconceptions has not yet been addressed in the plastic surgery literature. As such, we assessed medical students’ knowledge and perceptions of plastic surgery as a discipline and explored factors influencing these opinions. Methods: To assess medical students’ knowledge and perceptions of plastic surgery, we conducted an online survey. A total of 231 medical students responded. Interviews were then conducted with 2 focus groups, in which we explored the survey results and reasons behind these misconceptions. Results: As with previous studies, medical students showed a gap in knowledge with respect to plastic surgery. Although they were generally aware that plastic surgeons perform cosmetic procedures and treat burns, they were largely unaware that plastic surgeons perform hand and craniofacial surgeries. Focus groups revealed that television plays a large role in shaping their ideas of plastic surgery. Conclusion: Medical students have a skewed perception of the discipline of plastic surgery, and this is largely influenced by television. Interventions aimed at educating medical students on the matter are recommended, including a greater presence in the preclerkship medical school curriculum. PMID:29026812

Deformation processes within wheel-rail adhesion in contact area

NASA Astrophysics Data System (ADS)

Albagachiev, A. Yu; Keropyan, A. M.

2018-03-01

The study of working surface deformation during interaction of open-pit locomotive tires allowed defining outstanding features of phenomena occurring in the contact area of interacting surfaces. It was found that processes typical for plastic saturated contact occur in the area of wheel-rail interaction of industrial railway transport. In case of plastic deformation exposed to heavy loads typical for open-pit locomotives, upon all rough surfaces of the contour contact area being fully deformed, the frame on which they are found is exposed to plastic deformation. Plastic deformation of roughness within the contact area of interacting surfaces leads to the increase in the actual area of their contact and, therefore, increases the towing capacity of mining machines. Finally, the available data on deformation characteristics with regard to processes occurring in the contact area of wheel-rail interaction will allow making theoretical forecasts on the expected design value of friction coefficient and, therefore, the towing capacity of open-pit locomotives.

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

USGS Publications Warehouse

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.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

The town of North Hempstead has begun a pilot curbside plastic recycling program in the Manhasset area. The curbside pilot program is the second phase of the Town's plastic recycling effort. The first phase began in June, utilizing the 14 residential drop-off areas located conveniently throughout North Hempstead. The third phase will be implementation of curbside recycling of plastic throughout North Hempstead. Eventually the plastic recycling program will be phased in on a townwide basis, after the results of the pilot program are analyzed and adjustments are made for home sorting and curbside collection. The collected plastics will be deliveredmore » to the Solid Waste Management Authority's recycling center where it will be crushed and baled. The plastic will then be taken by Browning-Ferris Inc., who will pay the Authority $45.00 per ton for the material. The used plastic will then be converted into new plastic-based products.« less

Linking plant functional trait plasticity and the large increase in forest water use efficiency

NASA Astrophysics Data System (ADS)

Mastrotheodoros, Theodoros; Pappas, Christoforos; Molnar, Peter; Burlando, Paolo; Keenan, Trevor F.; Gentine, Pierre; Gough, Christopher M.; Fatichi, Simone

2017-09-01

Elevated atmospheric CO2 concentrations are expected to enhance photosynthesis and reduce stomatal conductance, thus increasing plant water use efficiency. A recent study based on eddy covariance flux observations from Northern Hemisphere forests showed a large increase in inherent water use efficiency (IWUE). Here we used an updated version of the same data set and robust uncertainty quantification to revisit these contemporary IWUE trends. We tested the hypothesis that the observed IWUE increase could be attributed to interannual trends in plant functional traits, potentially triggered by environmental change. We found that IWUE increased by 1.3% yr-1, which is less than previously reported but still larger than theoretical expectations. Numerical simulations with the Tethys-Chloris ecosystem model using temporally static plant functional traits cannot explain this increase. Simulations with plant functional trait plasticity, i.e., temporal changes in model parameters such as specific leaf area and maximum Rubisco capacity, match the observed trends in IWUE. Our results show that trends in plant functional traits, equal to 1.0% yr-1, can explain the observed IWUE trends. Thus, at decadal or longer time scales, trait plasticity could potentially influence forest water, carbon, and energy fluxes with profound implications for both the monitoring of temporal changes in plant functional traits and their representation in Earth system models.

Learning place cells, grid cells and invariances with excitatory and inhibitory plasticity

PubMed Central

2018-01-01

Neurons in the hippocampus and adjacent brain areas show a large diversity in their tuning to location and head direction, and the underlying circuit mechanisms are not yet resolved. In particular, it is unclear why certain cell types are selective to one spatial variable, but invariant to another. For example, place cells are typically invariant to head direction. We propose that all observed spatial tuning patterns – in both their selectivity and their invariance – arise from the same mechanism: Excitatory and inhibitory synaptic plasticity driven by the spatial tuning statistics of synaptic inputs. Using simulations and a mathematical analysis, we show that combined excitatory and inhibitory plasticity can lead to localized, grid-like or invariant activity. Combinations of different input statistics along different spatial dimensions reproduce all major spatial tuning patterns observed in rodents. Our proposed model is robust to changes in parameters, develops patterns on behavioral timescales and makes distinctive experimental predictions. PMID:29465399

Enabling Functional Neural Circuit Simulations with Distributed Computing of Neuromodulated Plasticity

PubMed Central

Potjans, Wiebke; Morrison, Abigail; Diesmann, Markus

2010-01-01

A major puzzle in the field of computational neuroscience is how to relate system-level learning in higher organisms to synaptic plasticity. Recently, plasticity rules depending not only on pre- and post-synaptic activity but also on a third, non-local neuromodulatory signal have emerged as key candidates to bridge the gap between the macroscopic and the microscopic level of learning. Crucial insights into this topic are expected to be gained from simulations of neural systems, as these allow the simultaneous study of the multiple spatial and temporal scales that are involved in the problem. In particular, synaptic plasticity can be studied during the whole learning process, i.e., on a time scale of minutes to hours and across multiple brain areas. Implementing neuromodulated plasticity in large-scale network simulations where the neuromodulatory signal is dynamically generated by the network itself is challenging, because the network structure is commonly defined purely by the connectivity graph without explicit reference to the embedding of the nodes in physical space. Furthermore, the simulation of networks with realistic connectivity entails the use of distributed computing. A neuromodulated synapse must therefore be informed in an efficient way about the neuromodulatory signal, which is typically generated by a population of neurons located on different machines than either the pre- or post-synaptic neuron. Here, we develop a general framework to solve the problem of implementing neuromodulated plasticity in a time-driven distributed simulation, without reference to a particular implementation language, neuromodulator, or neuromodulated plasticity mechanism. We implement our framework in the simulator NEST and demonstrate excellent scaling up to 1024 processors for simulations of a recurrent network incorporating neuromodulated spike-timing dependent plasticity. PMID:21151370

Abundance and composition of near surface microplastics and plastic debris in the Stockholm Archipelago, Baltic Sea.

PubMed

Gewert, Berit; Ogonowski, Martin; Barth, Andreas; MacLeod, Matthew

2017-07-15

We collected plastic debris in the Stockholm Archipelago using a manta trawl, and additionally along a transect in the Baltic Sea from the island of Gotland to Stockholm in a citizen science study. The samples were concentrated by filtration and organic material was digested using hydrogen peroxide. Suspected plastic material was isolated by visual sorting and 59 of these were selected to be characterized with Fourier transform infrared spectroscopy. Polypropylene and polyethylene were the most abundant plastics identified among the samples (53% and 24% respectively). We found nearly ten times higher abundance of plastics near central Stockholm than in offshore areas (4.2×10 5 plastics km -2 compared to 4.7×10 4 plastics km -2 ). The abundance of plastic debris near Stockholm was similar to urban areas in California, USA, and the overall abundance in the Stockholm Archipelago was similar to plastic abundance reported in the northwestern Mediterranean Sea. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

Review, mapping and analysis of the agricultural plastic waste generation and consolidation in Europe.

PubMed

Briassoulis, Demetres; Babou, Epifania; Hiskakis, Miltiadis; Scarascia, Giacomo; Picuno, Pietro; Guarde, Dorleta; Dejean, Cyril

2013-12-01

A review of agricultural plastic waste generation and consolidation in Europe is presented. A detailed geographical mapping of the agricultural plastic use and waste generation in Europe was conducted focusing on areas of high concentration of agricultural plastics. Quantitative data and analysis of the agricultural plastic waste generation by category, geographical distribution and compositional range, and physical characteristics of the agricultural plastic waste per use and the temporal distribution of the waste generation are presented. Data were collected and cross-checked from a variety of sources, including European, national and regional services and organizations, local agronomists, retailers and farmers, importers and converters. Missing data were estimated indirectly based on the recorded cultivated areas and the characteristics of the agricultural plastics commonly used in the particular regions. The temporal distribution, the composition and physical characteristics of the agricultural plastic waste streams were mapped by category and by application. This study represents the first systematic effort to map and analyse agricultural plastic waste generation and consolidation in Europe.

Inexpensive Dramatic Pneumatic Lift

NASA Astrophysics Data System (ADS)

Morse, Robert A.

2017-09-01

Various experiments and demonstrations relate air pressure and air pressure difference to force and area. Carpenter and Minnix describe a large-scale pneumatic lift in which a person sitting on a board atop a plastic garbage bag is lifted when the bag is connected to the exhaustport of a vacuum cleaner, which easily lifts the person. This article describes the construction and use of an inexpensive hand-held pneumatic lift to demonstrate the same principle.

Plastic superconductor bearings any size, any shape, 77 k and up

NASA Technical Reports Server (NTRS)

Reick, Franklin G.

1990-01-01

Friction free bearings at 77 k or higher are possible using the high T(sub c) copper oxide ceramic superconductors. The conventional method for making such bearings is to use a sintered ceramic monolith. This puts great restraints on size, shape and postforming machining. The material is hard and abrasive. It's possible to grind up ceramic superconductors and suspend the granules in a suitable matrix. Mechanical properties improve and are largely dependent on the binder. The Meissner effect is confined to individual grains containing electron vortices. Tracks, rails, levitation areas and bearings can be made this way with conventional plastic molding and extruding machines or by painting. The parts are easily machined. The sacrifice is in bulk electrical conductivity. A percolating wick feel for LN2 can be used to cool remote superconductors and large areas quite effectively. A hollow spheroid or cylinder of superconductor material can be molded with the internal surfaces shielded by the Meissner effect. It might be thought of as the dc magnetic analogue of the Faraday cage and the inside can be called the Meissner space. It's selective. The ac fields are transmitted with minor attenuation. Particle size and distribution have a profound effect on final magnetic and electrical characteristics.

REMODELING SENSORY CORTICAL MAPS IMPLANTS SPECIFIC BEHAVIORAL MEMORY

PubMed Central

Bieszczad, Kasia M.; Miasnikov, Alexandre A.; Weinberger, Norman M.

2013-01-01

Neural mechanisms underlying the capacity of memory to be rich with sensory detail are largely unknown. A candidate mechanism is learning-induced plasticity that remodels adult sensory cortex. Here, expansion in the primary auditory cortical (A1) tonotopic map of rats was induced by pairing a 3.66 kHz tone with activation of the nucleus basalis, mimicking the effects of natural associative learning. Remodeling of A1 produced de novo specific behavioral memory, but neither memory nor plasticity were consistently at the frequency of the paired tone, which typically decreased in A1 representation. Rather, there was a specific match between individual subjects’ area of expansion and the tone that was strongest in each animal’s memory, as determined by post-training frequency generalization gradients. These findings provide the first demonstration of a match between the artificial induction of specific neural representational plasticity and artificial induction of behavioral memory. As such, together with prior and present findings for detection, correlation and mimicry of plasticity with the acquisition of memory, they satisfy a key criterion for neural substrates of memory. This demonstrates that directly remodeling sensory cortical maps is sufficient for the specificity of memory formation. PMID:23639876

Remodeling of Dendritic Spines in the Avian Vocal Motor Cortex Following Deafening Depends on the Basal Ganglia Circuit.

PubMed

Zhou, Xin; Fu, Xin; Lin, Chun; Zhou, Xiaojuan; Liu, Jin; Wang, Li; Zhang, Xinwen; Zuo, Mingxue; Fan, Xiaolong; Li, Dapeng; Sun, Yingyu

2017-05-01

Deafening elicits a deterioration of learned vocalization, in both humans and songbirds. In songbirds, learned vocal plasticity has been shown to depend on the basal ganglia-cortical circuit, but the underlying cellular basis remains to be clarified. Using confocal imaging and electron microscopy, we examined the effect of deafening on dendritic spines in avian vocal motor cortex, the robust nucleus of the arcopallium (RA), and investigated the role of the basal ganglia circuit in motor cortex plasticity. We found rapid structural changes to RA dendritic spines in response to hearing loss, accompanied by learned song degradation. In particular, the morphological characters of RA spine synaptic contacts between 2 major pathways were altered differently. However, experimental disruption of the basal ganglia circuit, through lesions in song-specialized basal ganglia nucleus Area X, largely prevented both the observed changes to RA dendritic spines and the song deterioration after hearing loss. Our results provide cellular evidence to highlight a key role of the basal ganglia circuit in the motor cortical plasticity that underlies learned vocal plasticity. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

Ingestion of plastic marine debris by Common and Thick-billed Murres in the northwestern Atlantic from 1985 to 2012.

PubMed

Bond, Alexander L; Provencher, Jennifer F; Elliot, Richard D; Ryan, Pierre C; Rowe, Sherrylynn; Jones, Ian L; Robertson, Gregory J; Wilhelm, Sabina I

2013-12-15

Plastic ingestion by seabirds is a growing conservation issue, but there are few time series of plastic ingestion with large sample sizes for which one can assess temporal trends. Common and Thick-billed Murres (Uria aalge and U. lomvia) are pursuit-diving auks that are legally harvested in Newfoundland and Labrador, Canada. Here, we combined previously unpublished data on plastic ingestion (from the 1980s to the 1990s) with contemporary samples (2011-2012) to evaluate changes in murres' plastic ingestion. Approximately 7% of murres had ingested plastic, with no significant change in the frequency of ingestion among species or periods. The number of pieces of plastic/bird, and mass of plastic/bird were highest in the 1980s, lowest in the late 1990s, and intermediate in contemporary samples. Studying plastic ingestion in harvested seabird populations links harvesters to conservation and health-related issues and is a useful source of large samples for diet and plastic ingestion studies. Copyright © 2013 Elsevier Ltd. All rights reserved.

Wide-angle planar microtracking for quasi-static microcell concentrating photovoltaics

NASA Astrophysics Data System (ADS)

Price, Jared S.; Sheng, Xing; Meulblok, Bram M.; Rogers, John A.; Giebink, Noel C.

2015-02-01

Concentrating photovoltaics offer a way to lower the cost of solar power. However, the existing paradigm based on precise orientation of large-area concentrator modules towards the Sun limits their deployment to large, open land areas. Here, we explore an alternate approach using high-efficiency microcell photovoltaics embedded between a pair of plastic lenslet arrays to demonstrate quasi-static concentrating photovoltaic panels <1 cm thick that accomplish full-day tracking with >200x flux concentration ratio through small (<1 cm) lateral translation at fixed latitude tilt. Per unit of installed land area, cosine projection loss for fixed microtracking concentrating photovoltaic panels is ultimately offset by improved ground coverage relative to their conventional dual-axis counterparts, enabling a ~1.9x increase in daily energy output that may open up a new opportunity for compact, high-efficiency concentrating photovoltaics to be installed on rooftops and other limited-space urban environments.

Wide-angle planar microtracking for quasi-static microcell concentrating photovoltaics.

PubMed

Price, Jared S; Sheng, Xing; Meulblok, Bram M; Rogers, John A; Giebink, Noel C

2015-02-05

Concentrating photovoltaics offer a way to lower the cost of solar power. However, the existing paradigm based on precise orientation of large-area concentrator modules towards the Sun limits their deployment to large, open land areas. Here, we explore an alternate approach using high-efficiency microcell photovoltaics embedded between a pair of plastic lenslet arrays to demonstrate quasi-static concentrating photovoltaic panels <1 cm thick that accomplish full-day tracking with >200x flux concentration ratio through small (<1 cm) lateral translation at fixed latitude tilt. Per unit of installed land area, cosine projection loss for fixed microtracking concentrating photovoltaic panels is ultimately offset by improved ground coverage relative to their conventional dual-axis counterparts, enabling a ~1.9x increase in daily energy output that may open up a new opportunity for compact, high-efficiency concentrating photovoltaics to be installed on rooftops and other limited-space urban environments.

Inter-cortical Modulation from Premotor to Motor Plasticity.

PubMed

Huang, Ying-Zu; Chen, Rou-Shayn; Fong, Po-Yu; Rothwell, John C; Chuang, Wen-Li; Weng, Yi-Hsin; Lin, Wey-Yil; Lu, Chin-Song

2018-06-11

Plasticity is involved in daily activities but abnormal plasticity may be deleterious. In this study, we found that motor plasticity could be modulated by suppressing the premotor cortex with the theta burst form of repetitive transcranial magnetic stimulation. Such changes in motor plasticity were associated with reduced learning of a simple motor task. We postulate that the premotor cortex adjusts the amount of motor plasticity to modulate motor learning through heterosynaptic metaplasticity. The present results provide an insight into how the brain physiologically coordinates two different areas to bring them into a functional network. This concept could be employed to intervene in diseases with abnormal plasticity. Primary motor cortex (M1) plasticity is known to be influenced by the excitability and prior activation history of M1 itself. However, little is known about how its plasticity is influenced by other areas of the brain. In the present study on humans of either sex who were known to respond to theta burst stimulation from previous studies, we found plasticity of M1 could be modulated by suppressing the premotor cortex with the theta burst form of repetitive transcranial magnetic stimulation. Motor plasticity was distorted and disappeared 30 min and 120 min respectively after premotor excitability was suppressed. Further evaluation revealed that such changes in motor plasticity were associated with impaired learning of a simple motor task. We postulate that the premotor cortex modulates the amount of plasticity within M1 through heterosynaptic metaplasticity, and that this may impact on learning of a simple motor task previously shown to be directly affected by M1 plasticity. The present results provide an insight into how the brain physiologically coordinates two different areas to bring them into a functional network. Furthermore, such concepts could be translated into therapeutic approaches for diseases with aberrant plasticity. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

Hong Kong at the Pearl River Estuary: A hotspot of microplastic pollution.

PubMed

Fok, Lincoln; Cheung, P K

2015-10-15

Large plastic (>5mm) and microplastic (0.315-5mm) debris were collected from 25 beaches along the Hong Kong coastline. More than 90% consisted of microplastics. Among the three groups of microplastic debris, expanded polystyrene (EPS) represented 92%, fragments represented 5%, and pellets represented 3%. The mean microplastic abundance for Hong Kong was 5595items/m(2). This number is higher than international averages, indicating that Hong Kong is a hotspot of marine plastic pollution. Microplastic abundance was significantly higher on the west coast than on the east coast, indicating that the Pearl River, which is west of Hong Kong, may be a potential source of plastic debris. The amounts of large plastic and microplastic debris of the same types (EPS and fragments) were positively correlated, suggesting that the fragmentation of large plastic material may increase the quantity of beach microplastic debris. Copyright © 2015 Elsevier Ltd. All rights reserved.

Polybrominated diphenyl ethers in plastic products, indoor dust, sediment and fish from informal e-waste recycling sites in Vietnam: a comprehensive assessment of contamination, accumulation pattern, emissions, and human exposure.

PubMed

Anh, Hoang Quoc; Nam, Vu Duc; Tri, Tran Manh; Ha, Nguyen Manh; Ngoc, Nguyen Thuy; Mai, Pham Thi Ngoc; Anh, Duong Hong; Minh, Nguyen Hung; Tuan, Nguyen Anh; Minh, Tu Binh

2017-08-01

Residue concentrations of polybrominated diphenyl ethers (PBDEs) in different kinds of samples including consumer products, indoor dust, sediment and fish collected from two e-waste recycling sites, and some industrial, urban and suburban areas in Vietnam were determined to provide a comprehensive assessment of the contamination levels, accumulation pattern, emission potential and human exposure through dust ingestion and fish consumption. There was a large variation of PBDE levels in plastic parts of obsolete electronic equipment (from 1730 to 97,300 ng/g), which is a common result observed in consumer plastic products reported elsewhere. PBDE levels in indoor dust samples collected from e-waste recycling sites ranged from 250 to 8740 ng/g, which were markedly higher than those in industrial areas and household offices. Emission rate of PBDEs from plastic parts of disposed electronic equipment to dust was estimated to be in a range from 3.4 × 10 -7 to 1.2 × 10 -5 (year -1 ) for total PBDEs and from 2.9 × 10 -7 to 7.2 × 10 -6 (year -1 ) for BDE-209. Some fish species collected from ponds in e-waste recycling villages contained elevated levels of PBDEs, especially BDE-209, which were markedly higher than those in fish previously reported. Overall, levels and patterns of PBDE accumulation in different kinds of samples suggest significant emission from e-waste sites and that these areas are potential sources of PBDE contamination. Intakes of PBDEs via fish consumption were generally higher than those estimated through dust ingestion. Intake of BDE-99 and BDE-209 through dust ingestion contributes a large proportion due to higher concentrations in dust and fish. Body weight normalized daily intake through dust ingestion estimated for the e-waste recycling sites (0.10-3.46 ng/day/kg body wt.) were in a high range as compared to those reported in other countries. Our results highlight the potential releases of PBDEs from informal recycling activities and the high degree of human exposure and suggest the need for continuous investigations on environmental pollution and toxic impacts of e-waste-related hazardous chemicals.

Year-round Application of Water Curtain for Environmental Control in Greenhouse

NASA Astrophysics Data System (ADS)

Ibuki, R.; Sugita, E.

2011-12-01

In large area of Japan needs forced environmental control to cultivate yields in hard temperature condition. Water Curtain is applied in Japan for night time air temperature control of small greenhouse, making strawberry and covered by plastic film. Water is splayed on extended plastic film, located above strawberry and below roof film. Underground water is utilized for cooling in summer, and warming in winter. Heat exchange between water and ground, and also water and air in the greenhouse is occurring in this system. Furthermore, heat transfer by radiation effect is also controlled by water membrane. In winter night, infrared radiation through plastic film is reduced by water membrane because of its high absorption coefficient on wave length of infrared. Besides water has a high transparency on wave length of visible light. These features are useful on the daytime radiation control of greenhouse to maintain visible light level for photosynthesis and to reduce excess infrared, damages yields in summer. Also in daytime of sunny day in winter season, temperature is too high to cultivate yields in closed greenhouse. Under this situation, water curtain is useful to storage from broad area in greenhouse excess heat from air in the circulation water. Warm water is useful to maintain temperature in greenhouse. On the contrary, in summer season, water can storage heat in daytime and release in night time. Water curtain system will contribute to be a sustainable and low energy consumption system to maintain comfortable environment for yields growth. For this reason we are considering to use water curtain in year-round. At the first step of the year-round application, day time use in summer is experimentally investigated. General water curtain splays water on plastic film extended on metal pipe. In this situation water is gathered at valley part of the film. Then water membrane is partially made and radiation control is not effective at large area. Therefore we applied new covering way to realize higher water covering ratio. With this way selective reduction effect of water curtain, which reduce infrared more than visible light is quantitatively measured. Also small greenhouse to growth plants under it is settled to measure thermal net, heat absorption, water and air temperature variation and yields growth. From measurements way of making water membrane influenced water temperature elevation.

Polyethylene bio-degradation by caterpillars of the wax moth Galleria mellonella.

PubMed

Bombelli, Paolo; Howe, Christopher J; Bertocchini, Federica

2017-04-24

Plastics are synthetic polymers derived from fossil oil and largely resistant to biodegradation. Polyethylene (PE) and polypropylene (PP) represent ∼92% of total plastic production. PE is largely utilized in packaging, representing ∼40% of total demand for plastic products (www.plasticseurope.org) with over a trillion plastic bags used every year [1]. Plastic production has increased exponentially in the past 50 years (Figure S1A in Supplemental Information, published with this article online). In the 27 EU countries plus Norway and Switzerland up to 38% of plastic is discarded in landfills, with the rest utilized for recycling (26%) and energy recovery (36%) via combustion (www.plasticseurope.org), carrying a heavy environmental impact. Therefore, new solutions for plastic degradation are urgently needed. We report the fast bio-degradation of PE by larvae of the wax moth Galleria mellonella, producing ethylene glycol. Copyright © 2017 Elsevier Ltd. All rights reserved.

Multifunctions - liquid crystal displays

NASA Astrophysics Data System (ADS)

Bechteler, M.

1980-12-01

Large area liquid crystal displays up to 400 cm square were developed capable of displaying a large quantity of analog and digital information, such as required for car dashboards, communication systems, and data processing, while fulfilling the attendant requirements on view tilt angle and operating temperature range. Items incorporated were: low resistance conductive layers deposited by means of a sputtermachine, preshaped glasses and broken glassfibers, assuring perfect parallellism between glass plates, rubbed plastic layers for excellent electrooptical properties, and fluorescent plates for display illumination in bright sunlight as well as in dim light conditions. Prototypes are described for clock and automotive applications.

Archaeological and Paleontological Investigation at Kalaeloa (Barber’s Point), Honouliuli, ’EWA, O’Ahu Island, Federal Study Areas 1a and 1b, and State of Hawaii Optional Area 1,

DTIC Science & Technology

1981-07-01

gravel, slightly sticky, slightly plastic, massive structure. Granule size limestone decreases with depth. Color whitens with depth influenced by neutral...fish. Vertebrae from shark or ray are present in 2787 and 2745 and fragments of large toothed jaws, tentatively identified as crevally (ulua) are present...a white enameled 5-gallon liquid dispenser sits on top a wooden crate. The barracks is wired for lighting with a drop-cord light over the desks

CROSS-DISCIPLINARY PHYSICS AND RELATED AREAS OF SCIENCE AND TECHNOLOGY: Bilayer Photoresist Insulator for High Performance Organic Thin-Film Transistors on Plastic Films

NASA Astrophysics Data System (ADS)

Wang, He; Li, Chun-Hong; Pan, Feng; Wang, Hai-Bo; Yan, Dong-Hang

2009-11-01

A novel bilayer photoresist insulator is applied in flexible vanadyl-phthalocyanine (VOPc) organic thin-film transistors (OTFTs). The micron-size patterns of this photoresisit insulator can be directly defined only by photolithography without the etching process. Furthermore, these OTFTs exhibit high field-effect mobility (about 0.8 cm2/Vs) and current on/off ratio (about 106). In particular, they show rather low hysteresis (< 1 V). The results demonstrate that this bilayer photoresist insulator can be applied in large-area electronics and in the facilitation of patterning insulators.

Emergent Spatial Patterns of Excitatory and Inhibitory Synaptic Strengths Drive Somatotopic Representational Discontinuities and their Plasticity in a Computational Model of Primary Sensory Cortical Area 3b

PubMed Central

Grajski, Kamil A.

2016-01-01

Mechanisms underlying the emergence and plasticity of representational discontinuities in the mammalian primary somatosensory cortical representation of the hand are investigated in a computational model. The model consists of an input lattice organized as a three-digit hand forward-connected to a lattice of cortical columns each of which contains a paired excitatory and inhibitory cell. Excitatory and inhibitory synaptic plasticity of feedforward and lateral connection weights is implemented as a simple covariance rule and competitive normalization. Receptive field properties are computed independently for excitatory and inhibitory cells and compared within and across columns. Within digit representational zones intracolumnar excitatory and inhibitory receptive field extents are concentric, single-digit, small, and unimodal. Exclusively in representational boundary-adjacent zones, intracolumnar excitatory and inhibitory receptive field properties diverge: excitatory cell receptive fields are single-digit, small, and unimodal; and the paired inhibitory cell receptive fields are bimodal, double-digit, and large. In simulated syndactyly (webbed fingers), boundary-adjacent intracolumnar receptive field properties reorganize to within-representation type; divergent properties are reacquired following syndactyly release. This study generates testable hypotheses for assessment of cortical laminar-dependent receptive field properties and plasticity within and between cortical representational zones. For computational studies, present results suggest that concurrent excitatory and inhibitory plasticity may underlie novel emergent properties. PMID:27504086

Ultraclean and Direct Transfer of a Wafer-Scale MoS2 Thin Film onto a Plastic Substrate.

PubMed

Phan, Hoang Danh; Kim, Youngchan; Lee, Jinhwan; Liu, Renlong; Choi, Yongsuk; Cho, Jeong Ho; Lee, Changgu

2017-02-01

An ultraclean method to directly transfer a large-area MoS 2 film from the original growth substrate to a flexible substrate by using epoxy glue is developed. The transferred film is observed to be free of wrinkles and cracks and to be as smooth as the film synthesized on the original substrate. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Measurement of large strains in ropes using plastic optical fibers

DOEpatents

Williams, Jerry Gene; Smith, David Barton; Muhs, Jeffrey David

2006-02-14

A method for the direct measurement of large strains in ropes in situ using a plastic optical fiber, for example, perfluorocarbon or polymethyl methacrylate and Optical Time-Domain Reflectometer or other light time-of-flight measurement instrumentation. Protective sheaths and guides are incorporated to protect the plastic optical fiber. In one embodiment, a small rope is braided around the plastic optical fiber to impose lateral compressive forces to restrain the plastic optical fiber from slipping and thus experience the same strain as the rope. Methods are described for making reflective interfaces along the length of the plastic optical fiber and to provide the capability to measure strain within discrete segments of the rope. Interpretation of the data allows one to calculate the accumulated strain at any point in time and to determine if the rope has experienced local damage.

Physico-chemical properties of excavated plastic from landfill mining and current recycling routes.

PubMed

Canopoli, L; Fidalgo, B; Coulon, F; Wagland, S T

2018-06-01

In Europe over 5.25 billion tonnes of waste has been landfilled between 1995 and 2015. Among this large amount of waste, plastic represents typically 5-25 wt% which is significant and has the potential to be recycled and reintroduced into the circular economy. To date there is still however little information available of the opportunities and challenges in recovering plastics from landfill sites. In this review, the impacts of landfill chemistry on the degradation and/or contamination of excavated plastic waste are analysed. The feasibility of using excavated plastic waste as feedstock for upcycling to valuable chemicals or liquid fuels through thermochemical conversion is also critically discussed. The limited degradation that is experienced by many plastics in landfills (>20 years) which guarantee that large amount is still available is largely due to thermooxidative degradation and the anaerobic conditions. However, excavated plastic waste cannot be conventionally recycled due to high level of ash, impurities and heavy metals. Recent studies demonstrated that pyrolysis offers a cost effective alternative option to conventional recycling. The produced pyrolysis oil is expected to have similar characteristics to petroleum diesel oil. The production of valuable product from excavated plastic waste will also increase the feasibility of enhanced landfill mining projects. However, further studies are needed to investigate the uncertainties about the contamination level and degradation of excavated plastic waste and address their viability for being processed through pyrolysis. Copyright © 2018 Elsevier Ltd. All rights reserved.

The Role of mGlu Receptors in Hippocampal Plasticity Deficits in Neurological and Psychiatric Disorders: Implications for Allosteric Modulators as Novel Therapeutic Strategies

PubMed Central

Senter, Rebecca K.; Ghoshal, Ayan; Walker, Adam G.; Xiang, Zixiu; Niswender, Colleen M.; Conn, P. Jeffrey

2016-01-01

Long-term potentiation (LTP) and long-term depression (LTD) are two distinct forms of synaptic plasticity that have been extensively characterized at the Schaffer collateral-CA1 (SC-CA1) synapse and the mossy fiber (MF)-CA3 synapse within the hippocampus, and are postulated to be the molecular underpinning for several cognitive functions. Deficits in LTP and LTD have been implicated in the pathophysiology of several neurological and psychiatric disorders. Therefore, there has been a large effort focused on developing an understanding of the mechanisms underlying these forms of plasticity and novel therapeutic strategies that improve or rescue these plasticity deficits. Among many other targets, the metabotropic glutamate (mGlu) receptors show promise as novel therapeutic candidates for the treatment of these disorders. Among the eight distinct mGlu receptor subtypes (mGlu1-8), the mGlu1,2,3,5,7 subtypes are expressed throughout the hippocampus and have been shown to play important roles in the regulation of synaptic plasticity in this brain area. However, development of therapeutic agents that target these mGlu receptors has been hampered by a lack of subtype-selective compounds. Recently, discovery of allosteric modulators of mGlu receptors has provided novel ligands that are highly selective for individual mGlu receptor subtypes. The mGlu receptors modulate the multiple forms of synaptic plasticity at both SC-CA1 and MF synapses and allosteric modulators of mGlu receptors have emerged as potential therapeutic agents that may rescue plasticity deficits and improve cognitive function in patients suffering from multiple neurological and psychiatric disorders. PMID:27296640

Estimation of global plastic loads delivered by rivers into the sea

NASA Astrophysics Data System (ADS)

Schmidt, Christian; Krauth, Tobias; Klöckner, Phillipp; Römer, Melina-Sophie; Stier, Britta; Reemtsma, Thorsten; Wagner, Stephan

2017-04-01

A considerable fraction of marine plastic debris likely originates from land-based sources. Transport of plastics by rivers is a potential mechanism that connects plastic debris generated on land with the marine environment. We analyze existing and experimental data of plastic loads in rivers and relate these to the amount of mismanaged plastic waste (MMPW) generated in the river catchments. We find a positive relationship between the plastic load in rivers and the amount of MMPW. Using our empirical MMPW-plastic river load-relationship we estimated the annual plastic load for 1494 rivers, ranging from small first order streams to large rivers, which have an outlet to the sea. We estimate that the global load of plastic debris delivered by rivers to the sea is 39000 tons per year with a large 95% prediction interval between 247 tons per year and 16.7 million tons per year, respectively. Our best estimate is considerably lower than the estimated total land-based inputs which range between 4.8-12.7 million tons anually (Jambeck et al. 2015). Approximately 75% of the total load is transported by the 10 top-ranked rivers which are predominantly located in Asia. These river catchments encompass countries with a large population and high economic growth but an insufficient waste infrastructure. Reducing the plastic loads in these rivers by 50% would reduce the global inputs by 37%. Of the total MMPW generated within river catchments, only a small fraction of about 0.05 % has been found to be mobile in rivers. Thus, either only a small fraction of MMPW enters the river systems, or a substantial fraction of plastic debris accumulates in river systems world wide. References: Jambeck, J. R., R. Geyer, C. Wilcox, T. R. Siegler, M. Perryman, A. Andrady, R. Narayan, and K. L. Law (2015), Plastic waste inputs from land into the ocean, Science, 347(6223), 768-771, doi:10.1126/science.1260352.

Ductile fracture of cylindrical vessels containing a large flaw

NASA Technical Reports Server (NTRS)

Erdogan, F.; Irwin, G. R.; Ratwani, M.

1976-01-01

The fracture process in pressurized cylindrical vessels containing a relatively large flaw is considered. The flaw is assumed to be a part-through or through meridional crack. The flaw geometry, the yield behavior of the material, and the internal pressure are assumed to be such that in the neighborhood of the flaw the cylinder wall undergoes large-scale plastic deformations. Thus, the problem falls outside the range of applicability of conventional brittle fracture theories. To study the problem, plasticity considerations are introduced into the shell theory through the assumptions of fully-yielded net ligaments using a plastic strip model. Then a ductile fracture criterion is developed which is based on the concept of net ligament plastic instability. A limited verification is attempted by comparing the theoretical predictions with some existing experimental results.

Flexure-based Roll-to-roll Platform: A Practical Solution for Realizing Large-area Microcontact Printing

PubMed Central

Zhou, Xi; Xu, Huihua; Cheng, Jiyi; Zhao, Ni; Chen, Shih-Chi

2015-01-01

A continuous roll-to-roll microcontact printing (MCP) platform promises large-area nanoscale patterning with significantly improved throughput and a great variety of applications, e.g. precision patterning of metals, bio-molecules, colloidal nanocrystals, etc. Compared with nanoimprint lithography, MCP does not require a thermal imprinting step (which limits the speed and material choices), but instead, extreme precision with multi-axis positioning and misalignment correction capabilities for large area adaptation. In this work, we exploit a flexure-based mechanism that enables continuous MCP with 500 nm precision and 0.05 N force control. The fully automated roll-to-roll platform is coupled with a new backfilling MCP chemistry optimized for high-speed patterning of gold and silver. Gratings of 300, 400, 600 nm line-width at various locations on a 4-inch plastic substrate are fabricated at a speed of 60 cm/min. Our work represents the first example of roll-to-roll MCP with high reproducibility, wafer scale production capability at nanometer resolution. The precision roll-to-roll platform can be readily applied to other material systems. PMID:26037147

EDITORIAL: Proceedings of the IUTAM Symposium on Plasticity at the Micron Scale, Technical University of Denmark, 21 25 Mark 2006

NASA Astrophysics Data System (ADS)

Tvergaard, Viggo

2007-01-01

This special issue constitutes the Proceedings of the IUTAM Symposium on Plasticity at the Micron Scale, held at the Technical University of Denmark, 21-25 May 2006. The purpose of this symposium was to gather a group of leading scientists working in areas of importance to length scale dependent plasticity. This includes work on phenomenological strain gradient plasticity models, studies making use of discrete dislocation models, and even atomic level models. Experimental investigations are central to all this, as all the models focus on developing an improved understanding of real observed phenomena. The opening lecture by Professor N A Fleck, Cambridge University, discussed experimental as well as theoretical approaches. Also, recent results for the surface roughness at grain boundaries were presented based on experiments and crystal plasticity modelling. A number of presentations focused on experiments for metals at a small length scale, e.g. using indenters or a small single crystal compression test. It was found that there are causes of the size effects other than the geometrically necessary dislocations related to strain gradients. Several lectures on scale dependent phenomenological plasticity theories discussed different methods of incorporating the characteristic material length. This included lower order plasticity theories as well as higher order theories, within standard plasticity models or crystal plasticity. Differences in the ways of incorporating higher order boundary conditions were the subject of much discussion. Various methods for discrete dislocation modelling of plastic deformation were used in some of the presentations to obtain a more detailed understanding of length scale effects in metals. This included large scale computations for dislocation dynamics as well as new statistical mechanics approaches to averaging of dislocation plasticity. Furthermore, at a somewhat larger length scale, applications of scale dependent plasticity to granular media and to cellular solids were discussed. The symposium consisted of thirty-six lectures, all of which were invited based on strong expertise in the area. Some of the lectures are not represented in this special issue, mainly because of prior commitments to publish elsewhere. The international Scientific Committee responsible for the symposium comprised the following: Professor V Tvergaard (Chairman) Denmark Professor A Benallal France Professor N A Fleck UK Professor L B Freund (IUTAM Representative) USA Professor E van der Giessen The Netherlands Professor J W Hutchinson USA Professor A Needleman USA Professor B Svendsen Germany The Committee gratefully acknowledges financial support for the symposium from the International Union of Theoretical and Applied Mechanics, from Novo Nordisk A/S and from the Villum Kann Rasmussen Foundation. In the organization of all parts of the symposium the enthusiastic participation of Dr C F Niordson and Dr P Redanz was invaluable. The smooth running of the symposium also owes much to the efforts and organizational skills of Bente Andersen.

Innovative plasticized alginate obtained by thermo-mechanical mixing: Effect of different biobased polyols systems.

PubMed

Gao, Chengcheng; Pollet, Eric; Avérous, Luc

2017-02-10

Plasticized alginate films with different biobased polyols (glycerol and sorbitol) and their mixtures were successfully prepared by thermo-mechanical mixing instead of the usual casting-evaporation procedure. The microstructure and properties of the different plasticized alginate formulations were investigated by SEM, FTIR, XRD, DMTA and uniaxial tensile tests. SEM and XRD results showed that native alginate particles were largely destructured with the plasticizers (polyols and water), under a thermo-mechanical input. With increasing amount of plasticizers, the samples showed enhanced homogeneity while their thermal and mechanical properties decreased. Compared to sorbitol, glycerol resulted in alginate films with a higher flexibility due to its better plasticization efficiency resulting from its smaller size and higher hydrophilic character. Glycerol and sorbitol mixtures seemed to be an optimum to obtain the best properties. This work showed that thermo-mechanical mixing is a promising method to produce, at large scale, plasticized alginate-based films with improved properties. Copyright © 2016 Elsevier Ltd. All rights reserved.

Neuroimaging Evidence for 2 Types of Plasticity in Association with Visual Perceptual Learning.

PubMed

Shibata, Kazuhisa; Sasaki, Yuka; Kawato, Mitsuo; Watanabe, Takeo

2016-09-01

Visual perceptual learning (VPL) is long-term performance improvement as a result of perceptual experience. It is unclear whether VPL is associated with refinement in representations of the trained feature (feature-based plasticity), improvement in processing of the trained task (task-based plasticity), or both. Here, we provide empirical evidence that VPL of motion detection is associated with both types of plasticity which occur predominantly in different brain areas. Before and after training on a motion detection task, subjects' neural responses to the trained motion stimuli were measured using functional magnetic resonance imaging. In V3A, significant response changes after training were observed specifically to the trained motion stimulus but independently of whether subjects performed the trained task. This suggests that the response changes in V3A represent feature-based plasticity in VPL of motion detection. In V1 and the intraparietal sulcus, significant response changes were found only when subjects performed the trained task on the trained motion stimulus. This suggests that the response changes in these areas reflect task-based plasticity. These results collectively suggest that VPL of motion detection is associated with the 2 types of plasticity, which occur in different areas and therefore have separate mechanisms at least to some degree. © The Author 2016. Published by Oxford University Press.

Evolution of Residual-Strain Distribution through an Overload-Induced Retardation Period during Fatigue Crack Growth

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lee, S. Y.; Sun, Yinan; An, Ke

2010-01-01

Neutron diffraction was employed to investigate the crack-growth retardation phenomenon after a single tensile overload by mapping both one-dimensional and two-dimensional residual-strain distributions around the crack tip in a series of compact-tension specimens representing various crack-growth stages through an overload-induced retardation period. The results clearly show a large compressive residual-strain field near the crack tip immediately after the overload. As the fatigue crack propagates through the overload-induced plastic zone, the compressive residual strains are gradually relaxed, and a new compressive residual-strain field is developed around the propagating crack tip, illustrating that the subsequent fatigue-induced plastic zone grows out of themore » large plastic zone caused by the overloading. The relationship between the overload-induced plastic zone and subsequent fatigue-induced plastic zone, and its influence on the residual-strain distributions in the perturbed plastic zone are discussed.« less

Oceanic barnacles act as foundation species on plastic debris: implications for marine dispersal.

PubMed

Gil, Michael A; Pfaller, Joseph B

2016-01-27

Plastic has emerged as an abundant, stable substratum for oceanic dispersal of organisms via rafting. However, the ecological mechanisms underlying community diversity on plastic debris remain poorly understood. On a cruise from California to Hawai'i, we surveyed plastic debris, some likely originating from the 2011 Tōhoku tsunami, to examine the relationship between rafting community diversity and both habitat area and stalked barnacle (Lepas spp.) abundance. For sessile taxa richness, we observed an interaction in which the positive effect of debris area weakened the negative effect of barnacle cover. In contrast, for mobile taxa richness, including cohabiting species from opposite sides of the Pacific Ocean, barnacle abundance had a positive effect that was strongest at smaller debris sizes. These findings suggest that barnacles, through interactions with habitat area, have trait-dependent effects on other species, serving as both foundation species and competitors, mediating the diversity and dispersal potential of marine organisms on plastic debris.

Oceanic barnacles act as foundation species on plastic debris: implications for marine dispersal

PubMed Central

Gil, Michael A.; Pfaller, Joseph B.

2016-01-01

Plastic has emerged as an abundant, stable substratum for oceanic dispersal of organisms via rafting. However, the ecological mechanisms underlying community diversity on plastic debris remain poorly understood. On a cruise from California to Hawai’i, we surveyed plastic debris, some likely originating from the 2011 Tōhoku tsunami, to examine the relationship between rafting community diversity and both habitat area and stalked barnacle (Lepas spp.) abundance. For sessile taxa richness, we observed an interaction in which the positive effect of debris area weakened the negative effect of barnacle cover. In contrast, for mobile taxa richness, including cohabiting species from opposite sides of the Pacific Ocean, barnacle abundance had a positive effect that was strongest at smaller debris sizes. These findings suggest that barnacles, through interactions with habitat area, have trait-dependent effects on other species, serving as both foundation species and competitors, mediating the diversity and dispersal potential of marine organisms on plastic debris. PMID:26813348

Spatiotemporal and Long Lasting Modulation of 11 Key Nogo Signaling Genes in Response to Strong Neuroexcitation

PubMed Central

Karlsson, Tobias E.; Wellfelt, Katrin; Olson, Lars

2017-01-01

Inhibition of nerve growth and plasticity in the CNS is to a large part mediated by Nogo-like signaling, now encompassing a plethora of ligands, receptors, co-receptors and modulators. Here we describe the distribution and levels of mRNA encoding 11 key genes involved in Nogo-like signaling (Nogo-A, Oligodendrocyte-Myelin glycoprotein (OMgp), Nogo receptor 1 (NgR1), NgR2, NgR3, Lingo-1, TNF receptor orphan Y (Troy), Olfactomedin, Lateral olfactory tract usher substance (Lotus) and membrane-type matrix metalloproteinase-3 (MT3-MPP)), as well as BDNF and GAPDH. Expression was analyzed in nine different brain areas before, and at eight time points during the first 3 days after a strong neuroexcitatory stimulation, caused by one kainic acid injection. A temporo-spatial pattern of orderly transcriptional regulations emerges that strengthens the role of Nogo-signaling mechanisms for synaptic plasticity in synchrony with transcriptional increases of BDNF mRNA. For most Nogo-type signaling genes, the largest alterations of mRNA levels occur in the dentate gyrus, with marked alterations also in the CA1 region. Changes occurred somewhat later in several areas of the cerebral cortex. The detailed spatio-temporal pattern of mRNA presence and kainic acid-induced transcriptional response is gene-specific. We reveal that several different gene alterations combine to decrease (and later increase) Nogo-like signaling, as expected to allow structural plasticity responses. Other genes are altered in the opposite direction, suggesting that the system prepares in advance in order to rapidly restore balance. However, the fact that Lingo-1 shows a seemingly opposite, plasticity inhibiting response to kainic acid (strong increase of mRNA in the dentate gyrus), may instead suggest a plasticity-enhancing intracellular function of this presumed NgR1 co-receptor. PMID:28442990

Plastic and the nest entanglement of urban and agricultural crows.

PubMed

Townsend, Andrea K; Barker, Christopher M

2014-01-01

Much attention has been paid to the impacts of plastics and other debris on marine organisms, but the effects of plastic on terrestrial organisms have been largely ignored. Detrimental effects of terrestrial plastic could be most pronounced in intensively human-modified landscapes (e.g., urban and agricultural areas), which are a source of much anthropogenic debris. Here, we examine the occurrence, types, landscape associations, and consequences of anthropogenic nest material in the American crow (Corvus brachyrhynchos), a North American species that breeds in both urban and agricultural landscapes. We monitored 195 nestlings in 106 nests across an urban and agricultural gradient in the Sacramento Valley, California, USA. We found that 85.2% of crow nests contained anthropogenic material, and 11 of 195 nestlings (5.6%) were entangled in their nests. The length of the material was greater in nests in agricultural territories than in urban territories, and the odds of entanglement increased 7.55 times for each meter of anthropogenic material in the nest. Fledging success was significantly lower for entangled than for unentangled nestlings. In all environments, particularly urban, agricultural, and marine, careful disposal of potential hazards (string, packing and hay bale twine, balloon ribbon, wire, fishing line) could reduce the occurrence of entanglement of nestling birds.

Plastic and the Nest Entanglement of Urban and Agricultural Crows

PubMed Central

Townsend, Andrea K.; Barker, Christopher M.

2014-01-01

Much attention has been paid to the impacts of plastics and other debris on marine organisms, but the effects of plastic on terrestrial organisms have been largely ignored. Detrimental effects of terrestrial plastic could be most pronounced in intensively human-modified landscapes (e.g., urban and agricultural areas), which are a source of much anthropogenic debris. Here, we examine the occurrence, types, landscape associations, and consequences of anthropogenic nest material in the American crow (Corvus brachyrhynchos), a North American species that breeds in both urban and agricultural landscapes. We monitored 195 nestlings in 106 nests across an urban and agricultural gradient in the Sacramento Valley, California, USA. We found that 85.2% of crow nests contained anthropogenic material, and 11 of 195 nestlings (5.6%) were entangled in their nests. The length of the material was greater in nests in agricultural territories than in urban territories, and the odds of entanglement increased 7.55 times for each meter of anthropogenic material in the nest. Fledging success was significantly lower for entangled than for unentangled nestlings. In all environments, particularly urban, agricultural, and marine, careful disposal of potential hazards (string, packing and hay bale twine, balloon ribbon, wire, fishing line) could reduce the occurrence of entanglement of nestling birds. PMID:24498238

What can aquatic gastropods tell us about phenotypic plasticity? A review and meta-analysis

PubMed Central

Bourdeau, P E; Butlin, R K; Brönmark, C; Edgell, T C; Hoverman, J T; Hollander, J

2015-01-01

There have been few attempts to synthesise the growing body of literature on phenotypic plasticity to reveal patterns and generalities about the extent and magnitude of plastic responses. Here, we conduct a review and meta-analysis of published literature on phenotypic plasticity in aquatic (marine and freshwater) gastropods, a common system for studying plasticity. We identified 96 studies, using pre-determined search terms, published between 1985 and November 2013. The literature was dominated by studies of predator-induced shell form, snail growth rates and life history parameters of a few model taxa, accounting for 67% of all studies reviewed. Meta-analyses indicated average plastic responses in shell thickness, shell shape, and growth and fecundity of freshwater species was at least three times larger than in marine species. Within marine gastropods, species with planktonic development had similar average plastic responses to species with benthic development. We discuss these findings in the context of the role of costs and limits of phenotypic plasticity and environmental heterogeneity as important constraints on the evolution of plasticity. We also consider potential publication biases and discuss areas for future research, indicating well-studied areas and important knowledge gaps. PMID:26219231

Anthropogenic marine litter composition in coastal areas may be a predictor of potentially invasive rafting fauna

PubMed Central

Borrell Pichs, Yaisel J.; García-Vazquez, Eva

2018-01-01

Anthropogenic plastic pollution is a global problem. In the marine environment, one of its less studied effects is the transport of attached biota, which might lead to introductions of non-native species in new areas or aid in habitat expansions of invasive species. The goal of the present work was to assess if the material composition of beached anthropogenic litter is indicative of the rafting fauna in a coastal area and could thus be used as a simple and cost-efficient tool for risk assessment in the future. Beached anthropogenic litter and attached biota along the 200 km coastline of Asturias, central Bay of Biscay, Spain, were analysed. The macrobiotic community attached to fouled litter items was identified using genetic barcoding combined with visual taxonomic analysis, and compared between hard plastics, foams, other plastics and non-plastic items. On the other hand, the material composition of beached litter was analysed in a standardized area on each beach. From these two datasets, the expected frequency of several rafting taxa was calculated for the coastal area and compared to the actually observed frequencies. The results showed that plastics were the most abundant type of beached litter. Litter accumulation was likely driven by coastal sources (industry, ports) and river/sewage inputs and transported by near-shore currents. Rafting vectors were almost exclusively made up of plastics and could mainly be attributed to fishing activity and leisure/ household. We identified a variety of rafting biota, including species of goose barnacles, acorn barnacles, bivalves, gastropods, polychaetes and bryozoan, and hydrozoan colonies attached to stranded litter. Several of these species were non-native and invasive, such as the giant Pacific oyster (Crassostrea gigas) and the Australian barnacle (Austrominius modestus). The composition of attached fauna varied strongly between litter items of different materials. Plastics, except for foam, had a much more diverse attached community than non-plastic materials. The predicted frequency of several taxa attached to beached litter significantly correlated with the actually observed frequencies. Therefore we suggest that the composition of stranded litter on a beach or an area could allow for predictions about the corresponding attached biotic community, including invasive species. PMID:29385195

Anthropogenic marine litter composition in coastal areas may be a predictor of potentially invasive rafting fauna.

PubMed

Rech, Sabine; Borrell Pichs, Yaisel J; García-Vazquez, Eva

2018-01-01

Anthropogenic plastic pollution is a global problem. In the marine environment, one of its less studied effects is the transport of attached biota, which might lead to introductions of non-native species in new areas or aid in habitat expansions of invasive species. The goal of the present work was to assess if the material composition of beached anthropogenic litter is indicative of the rafting fauna in a coastal area and could thus be used as a simple and cost-efficient tool for risk assessment in the future. Beached anthropogenic litter and attached biota along the 200 km coastline of Asturias, central Bay of Biscay, Spain, were analysed. The macrobiotic community attached to fouled litter items was identified using genetic barcoding combined with visual taxonomic analysis, and compared between hard plastics, foams, other plastics and non-plastic items. On the other hand, the material composition of beached litter was analysed in a standardized area on each beach. From these two datasets, the expected frequency of several rafting taxa was calculated for the coastal area and compared to the actually observed frequencies. The results showed that plastics were the most abundant type of beached litter. Litter accumulation was likely driven by coastal sources (industry, ports) and river/sewage inputs and transported by near-shore currents. Rafting vectors were almost exclusively made up of plastics and could mainly be attributed to fishing activity and leisure/ household. We identified a variety of rafting biota, including species of goose barnacles, acorn barnacles, bivalves, gastropods, polychaetes and bryozoan, and hydrozoan colonies attached to stranded litter. Several of these species were non-native and invasive, such as the giant Pacific oyster (Crassostrea gigas) and the Australian barnacle (Austrominius modestus). The composition of attached fauna varied strongly between litter items of different materials. Plastics, except for foam, had a much more diverse attached community than non-plastic materials. The predicted frequency of several taxa attached to beached litter significantly correlated with the actually observed frequencies. Therefore we suggest that the composition of stranded litter on a beach or an area could allow for predictions about the corresponding attached biotic community, including invasive species.

Surface plasticity: theory and computation

NASA Astrophysics Data System (ADS)

Esmaeili, A.; Steinmann, P.; Javili, A.

2017-11-01

Surfaces of solids behave differently from the bulk due to different atomic rearrangements and processes such as oxidation or aging. Such behavior can become markedly dominant at the nanoscale due to the large ratio of surface area to bulk volume. The surface elasticity theory (Gurtin and Murdoch in Arch Ration Mech Anal 57(4):291-323, 1975) has proven to be a powerful strategy to capture the size-dependent response of nano-materials. While the surface elasticity theory is well-established to date, surface plasticity still remains elusive and poorly understood. The objective of this contribution is to establish a thermodynamically consistent surface elastoplasticity theory for finite deformations. A phenomenological isotropic plasticity model for the surface is developed based on the postulated elastoplastic multiplicative decomposition of the surface superficial deformation gradient. The non-linear governing equations and the weak forms thereof are derived. The numerical implementation is carried out using the finite element method and the consistent elastoplastic tangent of the surface contribution is derived. Finally, a series of numerical examples provide further insight into the problem and elucidate the key features of the proposed theory.

Anisometric C 60 Fullerene Colloids Assisted by Structure-Directing Agent

DOE Office of Scientific and Technical Information (OSTI.GOV)

Penterman, S.; Liddell Watson, Chekesha M.; Escobedo, Fernando A.

2016-08-05

Colloidal synthesis and assembly provide low cost, large area routes to mesoscale structures. In particular, shape-anisotropic particles may form crystalline, plastic crystalline, complex liquid crystalline and glassy phases. Arrangements in each order class have been used to generate photonic materials. For example, large photonic band gaps have been found for photonic crystals, hyperuniform photonic glasses, and also for plastic crystals at sufficient refractive index contrast. The latter structures support highly isotropic bandgaps that are desirable for free-form waveguides and LED out-coupling. Photonic glasses with optical gain lead to self-tuned lasing by the superposition of multiply scattered light. Typically, extrinsic mediamore » such as organic dyes, rare earths, lanthanides and quantum dots are used to impart optical gain in photonic solids. The present work advances fullerene microcrystals as a new materials platform for ‘active’ light emitting in colloid-based photonic crystals. Fullerenes support singlet excited states that recombine to produce a characteristic red photoluminescence. C 60 also has a high refractive index (n ~ 2.2) and transparency (> 560 nm) 9 so that inverse structures are not required.« less

Thermodynamically consistent constitutive equations for nonisothermal large strain, elasto-plastic, creep behavior

NASA Technical Reports Server (NTRS)

Riff, R.; Carlson, R. L.; Simitses, G. J.

1985-01-01

The paper is concerned with the development of constitutive relations for large nonisothermal elastic-viscoplastic deformations for metals. The kinematics of elastic-plastic deformation, valid for finite strains and rotations, is presented. The resulting elastic-plastic uncoupled equations for the deformation rate combined with use of the incremental elasticity law permits a precise and purely deductive development of elastic-viscoplastic theory. It is shown that a phenomenological thermodynamic theory in which the elastic deformation and the temperature are state variables, including few internal variables, can be utilized to construct elastic-viscoplastic constitutive equations, which are appropriate for metals. The limiting case of inviscid plasticity is examined.

Development of a Fatigue Crack Growth Coupon for Highly Plastic Stress Conditions

NASA Technical Reports Server (NTRS)

Allen, Phillip A.; Aggarwal, Pravin K.; Swanson, Gregory R.

2003-01-01

This paper presents an analytical approach used to develop a novel fatigue crack growth coupon for a highly plastic 3-D stress field condition. The flight hardware investigated in this paper is a large separation bolt that fractures using pyrotechnics at the appointed time during the flight sequence. The separation bolt has a deep notch that produces a severe stress concentration and a large plastic zone when highly loaded. For this geometry, linear-elastic fracture mechanics (LEFM) techniques are not valid due to the large nonlinear stress field. Unfortunately, industry codes that are generally available for fracture mechanics analysis and fatigue crack growth (e.g. NASGRO (11) are limited to LEFM and are available for only a limited number of geometries. The results of LEFM based codes are questionable when used on geometries with significant plasticity. Therefore elastic-plastic fracture mechanics (EPFM) techniques using the finite element method (FEM) were used to analyze the bolt and test coupons. scale flight hardware is very costly in t e r n of assets, laboratory resources, and schedule. Therefore to alleviate some of these problems, a series of novel test coupons were developed to simulate the elastic-plastic stress field present in the bolt.

Trait coordination, mechanical behaviour and growth form plasticity of Amborella trichopoda under variation in canopy openness

PubMed Central

Trueba, Santiago; Isnard, Sandrine; Barthélémy, Daniel; Olson, Mark E.

2016-01-01

Understanding the distribution of traits across the angiosperm phylogeny helps map the nested hierarchy of features that characterize key nodes. Finding that Amborella is sister to the rest of the angiosperms has raised the question of whether it shares certain key functional trait characteristics, and plastic responses apparently widespread within the angiosperms at large. With this in mind, we test the hypothesis that local canopy openness induces plastic responses. We used this variation in morphological and functional traits to estimate the pervasiveness of trait scaling and leaf and stem economics. We studied the architecture of Amborella and how it varies under different degrees of canopy openness. We analyzed the coordination of 12 leaf and stem structural and functional traits, and the association of this covariation with differing morphologies. The Amborella habit is made up of a series of sympodial modules that vary in size and branching pattern under different canopy openness. Amborella stems vary from self-supporting to semi-scandent. Changes in stem elongation and leaf size in Amborella produce distinct morphologies under different light environments. Correlations were found between most leaf and stem functional traits. Stem tissue rigidity decreased with increasing canopy openness. Despite substantial modulation of leaf size and leaf mass per area by light availability, branches in different light environments had similar leaf area-stem size scaling. The sympodial growth observed in Amborella could point to an angiosperm synapomorphy. Our study provides evidence of intraspecific coordination between leaf and stem economic spectra. Trait variation along these spectra is likely adaptive under different light environments and is consistent with these plastic responses having been present in the angiosperm common ancestor. PMID:27672131

Responses of large mammals to climate change.

PubMed

Hetem, Robyn S; Fuller, Andrea; Maloney, Shane K; Mitchell, Duncan

2014-01-01

Most large terrestrial mammals, including the charismatic species so important for ecotourism, do not have the luxury of rapid micro-evolution or sufficient range shifts as strategies for adjusting to climate change. The rate of climate change is too fast for genetic adaptation to occur in mammals with longevities of decades, typical of large mammals, and landscape fragmentation and population by humans too widespread to allow spontaneous range shifts of large mammals, leaving only the expression of latent phenotypic plasticity to counter effects of climate change. The expression of phenotypic plasticity includes anatomical variation within the same species, changes in phenology, and employment of intrinsic physiological and behavioral capacity that can buffer an animal against the effects of climate change. Whether that buffer will be realized is unknown, because little is known about the efficacy of the expression of plasticity, particularly for large mammals. Future research in climate change biology requires measurement of physiological characteristics of many identified free-living individual animals for long periods, probably decades, to allow us to detect whether expression of phenotypic plasticity will be sufficient to cope with climate change.

Responses of large mammals to climate change

PubMed Central

Hetem, Robyn S; Fuller, Andrea; Maloney, Shane K; Mitchell, Duncan

2014-01-01

Most large terrestrial mammals, including the charismatic species so important for ecotourism, do not have the luxury of rapid micro-evolution or sufficient range shifts as strategies for adjusting to climate change. The rate of climate change is too fast for genetic adaptation to occur in mammals with longevities of decades, typical of large mammals, and landscape fragmentation and population by humans too widespread to allow spontaneous range shifts of large mammals, leaving only the expression of latent phenotypic plasticity to counter effects of climate change. The expression of phenotypic plasticity includes anatomical variation within the same species, changes in phenology, and employment of intrinsic physiological and behavioral capacity that can buffer an animal against the effects of climate change. Whether that buffer will be realized is unknown, because little is known about the efficacy of the expression of plasticity, particularly for large mammals. Future research in climate change biology requires measurement of physiological characteristics of many identified free-living individual animals for long periods, probably decades, to allow us to detect whether expression of phenotypic plasticity will be sufficient to cope with climate change. PMID:27583293

From Lobster Shells to Plastic Objects: A Bioplastics Activity

ERIC Educational Resources Information Center

Hudson, Reuben; Glaisher, Samuel; Bishop, Alexandra; Katz, Jeffrey L.

2015-01-01

A multiple day activity for students to create large-scale plastic objects from the biopolymer chitin (major component of lobster, crab, and shrimp shells) is described. The plastic objects created are durable and made from benign materials, making them suitable for students to take home to play with. Since the student-created plastic objects are…

Plastic ingestion by Black-footed Albatross Phoebastria nigripes from Kure Atoll, Hawai'i: Linking chick diet remains and parental at-sea foraging distributions

USGS Publications Warehouse

Hyrenbach, K. David; Hester, Michelle M.; Adams, Josh; Titmus, Andrew J.; Michael, Pam; Wahl, Travis; Chang, Chih-Wei; Marie, Amarisa; Vanderlip, Cynthia

2017-01-01

We quantified the incidence (percentage of samples with plastic) and loads (mass, volume) of four plastic types (fragments, line, sheet, foam) ingested by Black-footed Albatross Phoebastria nigripes chicks raised on Kure Atoll, the westernmost Hawaiian colony. All 25 samples contained plastic, mostly in the form of foam and line. On average (± SD), boluses and stomachs contained 28.2 ± 14.3 g and 40.3 ± 29.0 g of plastic, respectively. Plastic was the dominant indigestible material in the boluses and the stomach samples, accounting for 48.8%-89.7% of the bolus mass (mean 67.4 ± 12.1%, median 67.5%, n = 20), and for 18.2%-94.1% of the stomach content mass (mean 70.0 ± 30.3%, median 75.6%, n = 5). Although the ingested plastic fragments ranged widely in size, most (92% in boluses, 91% in stomachs) were mesoplastics (5-25 mm), followed by macroplastics (>25 mm; 7% in boluses, 6% in stomachs), and microplastics (1-5 mm; 1% in boluses, 4% in stomachs). Yet the two fragment size distributions were significantly different, with more small-sized items (3-8 mm) in stomachs and with more large-sized items (46-72 mm) in boluses. To investigate where albatross parents collect this material, we tracked seven provisioning adults during 14 foraging trips using satellite-linked transmitters. The tracked birds foraged west of Kure Atoll (180–150°E, 30-40°N) and spent most of their time over pelagic waters (>2000 m deep; averaging 89 ± 9%), with substantial time over seamounts (averaging 11 ± 7%). Together, these results indicate that Black-footed Albatross chicks at Kure Atoll ingest plastics sourced by their parents foraging in waters of the western North Pacific. Provisioning adults forage within an area of surface convergence, downstream from the Kuroshio Current, and frequently visit seamounts northwest of the Hawaiian archipelago.

High-levels of microplastic pollution in a large, remote, mountain lake.

PubMed

Free, Christopher M; Jensen, Olaf P; Mason, Sherri A; Eriksen, Marcus; Williamson, Nicholas J; Boldgiv, Bazartseren

2014-08-15

Despite the large and growing literature on microplastics in the ocean, little information exists on microplastics in freshwater systems. This study is the first to evaluate the abundance, distribution, and composition of pelagic microplastic pollution in a large, remote, mountain lake. We quantified pelagic microplastics and shoreline anthropogenic debris in Lake Hovsgol, Mongolia. With an average microplastic density of 20,264 particles km(-2), Lake Hovsgol is more heavily polluted with microplastics than the more developed Lakes Huron and Superior in the Laurentian Great Lakes. Fragments and films were the most abundant microplastic types; no plastic microbeads and few pellets were observed. Household plastics dominated the shoreline debris and were comprised largely of plastic bottles, fishing gear, and bags. Microplastic density decreased with distance from the southwestern shore, the most populated and accessible section of the park, and was distributed by the prevailing winds. These results demonstrate that without proper waste management, low-density populations can heavily pollute freshwater systems with consumer plastics. Copyright © 2014 Elsevier Ltd. All rights reserved.

[Investigation and analysis of factors that affect the health of children in the plastic recycling and regeneration processing region].

PubMed

Wang, Juanli; Li, Liping; Lu, Yaogui

2014-09-01

To investigate the main influential factors for the health of children in the plastic waste recovery and recycling area. A cross-sectional survey was performed among children aged 9∼17 years from three natural villages engaged in plastic waste recovery and recycling and four control villages engaged in planting. The health status of children was investigated by random household survey using a face-to-face questionnaire, and the main influential factors were analyzed accordingly. The incidence rates of respiratory symptoms (cough and expectoration, nasal congestion, and sore throat) (78.4%, 69/88) and digestive diseases (gastrointestinal disease and liver disease) (14.8%, 13/88) in the waste processing area were significantly higher than those in the control area (64.0%, 71/111; 6.3%, 7/111) (P < 0.05). Multivariate logistic regression analysis indicated that skin diseases are related to whether plastic can be smelt around the residential area.

40 CFR 52.777 - Control strategy: photochemical oxidants (hydrocarbons).

Code of Federal Regulations, 2013 CFR

2013-07-01

... lithography operations, business plastics, automotive plastics, and synthetic organic chemical manufacturing..., automotive plastics, and synthetic organic chemical manufacturing industries (SOCMI) batch processes... Michigan area, and an agreed order between U.S. Steel (currently USX Corporation) and the IDEM signed by...

40 CFR 52.777 - Control strategy: photochemical oxidants (hydrocarbons).

Code of Federal Regulations, 2012 CFR

2012-07-01

... lithography operations, business plastics, automotive plastics, and synthetic organic chemical manufacturing..., automotive plastics, and synthetic organic chemical manufacturing industries (SOCMI) batch processes... Michigan area, and an agreed order between U.S. Steel (currently USX Corporation) and the IDEM signed by...

77 FR 64787 - Approval and Promulgation of Air Quality Implementation Plans; Maryland; Reasonably Available...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-10-23

... and plastic parts coatings; large appliance coatings; offset lithographic printing and letterpress... local air pollution control authorities information that should assist them in determining RACT for VOC... plastic parts coatings; (4) large appliance coatings; (5) offset lithographic printing and letterpress...

Advanced Multilayer Composite Heavy-Oxide Scintillator Detectors for High Efficiency Fast Neutron Detection

NASA Astrophysics Data System (ADS)

Ryzhikov, Vladimir D.; Naydenov, Sergei V.; Pochet, Thierry; Onyshchenko, Gennadiy M.; Piven, Leonid A.; Smith, Craig F.

2018-01-01

We have developed and evaluated a new approach to fast neutron and neutron-gamma detection based on large-area multilayer composite heterogeneous detection media consisting of dispersed granules of small-crystalline scintillators contained in a transparent organic (plastic) matrix. Layers of the composite material are alternated with layers of transparent plastic scintillator material serving as light guides. The resulting detection medium - designated as ZEBRA - serves as both an active neutron converter and a detection scintillator which is designed to detect both neutrons and gamma-quanta. The composite layers of the ZEBRA detector consist of small heavy-oxide scintillators in the form of granules of crystalline BGO, GSO, ZWO, PWO and other materials. We have produced and tested the ZEBRA detector of sizes 100x100x41 mm and greater, and determined that they have very high efficiency of fast neutron detection (up to 49% or greater), comparable to that which can be achieved by large sized heavy-oxide single crystals of about Ø40x80 cm3 volume. We have also studied the sensitivity variation to fast neutron detection by using different types of multilayer ZEBRA detectors of 100 cm2 surface area and 41 mm thickness (with a detector weight of about 1 kg) and found it to be comparable to the sensitivity of a 3He-detector representing a total cross-section of about 2000 cm2 (with a weight of detector, including its plastic moderator, of about 120 kg). The measured count rate in response to a fast neutron source of 252Cf at 2 m for the ZEBRA-GSO detector of size 100x100x41 mm3 was 2.84 cps/ng, and this count rate can be doubled by increasing the detector height (and area) up to 200x100 mm2. In summary, the ZEBRA detectors represent a new type of high efficiency and low cost solid-state neutron detector that can be used for stationary neutron/gamma portals. They may represent an interesting alternative to expensive, bulky gas counters based on 3He or 10B neutron detection technologies.

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

NASA Astrophysics Data System (ADS)

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

2017-06-01

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

A neuromorphic implementation of multiple spike-timing synaptic plasticity rules for large-scale neural networks

PubMed Central

Wang, Runchun M.; Hamilton, Tara J.; Tapson, Jonathan C.; van Schaik, André

2015-01-01

We present a neuromorphic implementation of multiple synaptic plasticity learning rules, which include both Spike Timing Dependent Plasticity (STDP) and Spike Timing Dependent Delay Plasticity (STDDP). We present a fully digital implementation as well as a mixed-signal implementation, both of which use a novel dynamic-assignment time-multiplexing approach and support up to 226 (64M) synaptic plasticity elements. Rather than implementing dedicated synapses for particular types of synaptic plasticity, we implemented a more generic synaptic plasticity adaptor array that is separate from the neurons in the neural network. Each adaptor performs synaptic plasticity according to the arrival times of the pre- and post-synaptic spikes assigned to it, and sends out a weighted or delayed pre-synaptic spike to the post-synaptic neuron in the neural network. This strategy provides great flexibility for building complex large-scale neural networks, as a neural network can be configured for multiple synaptic plasticity rules without changing its structure. We validate the proposed neuromorphic implementations with measurement results and illustrate that the circuits are capable of performing both STDP and STDDP. We argue that it is practical to scale the work presented here up to 236 (64G) synaptic adaptors on a current high-end FPGA platform. PMID:26041985

CPI (chemical processing industry) feeling impact of new-car sales slump

DOE Office of Scientific and Technical Information (OSTI.GOV)

Slaten, A.

1980-05-21

The slump in U.S. automobile production has reduced the automobile industry's demand for plastics. Nearly 5% (1.9 billion lb) of the 39.4 billion lb of plastic produced in 1979 were used in transportation (largely automotive) applications. According to A. Slaten of Rexene, automotive consumption of polypropylene will be down by 10-20% in 1980 from 1979's 440 million lb. According to Du Pont, the average 3000 lb automobile manufactured in 1980 contains about 200 lb of plastic, but by 1990, the average 2500 lb car will use 300-400 lb of plastic. According to Predicasts Inc., plastics use in automobiles will increasemore » by 8.4%/yr to a 6.15 billion lb market in 1995. The predicted annual growth rates for some plastics include: PVC, 4.4%; polyester (largely in sheet-molding compounds), 12.6%; polyethylene, 10.2%; nylon, 9.7%; acetals, 9.5%; polycarbonate, 7.2%; and polyurethane, 6.8%. Automobile production trends, the effect of the 1974-75 production downturn on plastics use in automobiles, and proposed government policies for aiding U.S. automobile manufacturers are discussed.« less

Impacts of macro - and microplastic on macrozoobenthos abundance in intertidal zone

NASA Astrophysics Data System (ADS)

Bangun, A. P.; Wahyuningsih, H.; Muhtadi, A.

2018-02-01

Plastics pollution in coastal areas is one of the topics that have received more attention over the past few years. The intertidal zone is a waters area that is directly affected by contamination of plastic waste from land and sea. The purpose of this study was to analyze the types and abundance of plastic waste in the intertidal zone and its impact on macrozoobenthos abundance. This research was conducted at Pesisir Desa Jaring Halus in February-April 2017. Macrozoobenthos and macro - micro plastic were collected by using quadratic transect. Sediments were collected with a core, to a depth of 30 cm. Microplastic and macroplastic abundances were analyzed using separation of sediment density and hand sorting. The dominant micro plastic types were film (52.30%), fiber (24.88%), fragments (22.74%), followed by pellets (0.1%). The total number of microplastics were 326,33 items and macro plastic were 308 items. Macroplastic abundance is positively correlated with microplastic (0.765). The abundance of macrozoobenthos is negatively correlated with microplastic abundance (-0.368) and with macro plastic abundance (-0.633). The management strategies were suggested clean up marine debris, decrease plastic using and built up the station of debris processing.

Design of an Airlift Bioreactor

DOE Data Explorer

Jiao, Yongqin; Park, Dan; Ho, Lewis

2017-03-13

An important consideration for the process design is cell immobilization-enabled flow-through operation. Large-scale biosorption relies on cells that are immobilized on a supporting substrate and used to 'attract' metal ions. Cell immobilization allows easy separation of the feed solution and REEs that are attached to the cell surface. It also allows continuous operation without the need of energy-intensive centrifugation or filtration. Lightweight, high surface area, low cost (~$200/m3) high-density polyethylene (HDPE) plastic disks are used as cell carriers for biofilm formation.

The effects of ingested plastic on growth and survival of albatross chicks

USGS Publications Warehouse

Sievert, Paul R.; Sileo, Louis

1993-01-01

We studied the effects of ingested plastic on the growth and survival of chicks of Laysan Albatrosses Diomedea immutabilis and Black-footed albatrosses D. nigripes on Midway Atoll during the nesting seasons of 1986 and 1987. Weights and proventricular contents of the chicks were determined periodically through the nesting cycle. Large (>22 cm1)volumes of plastic were present in the proventriculi of 27% of the Laysan and 16% of the Black-footed albatross chicks examined by endoscopy. Prior to fledging, albatross chicks regurgitated pellets composed of plastic and other indigestible material from their proventriculi. Laysan Albatross chicks with large volumes of proventricular plastic had asymptotic fledging weights significantly lower (122 g) than did chicks with low amounts of plastic. The effect of depresses fledging weights on postfledging survival was not determined. Plastic had no detectable effect on the growth of Black-footed Albatross chicks. All chicks that died were examined by necropsy. Mechanical lesions from ingested plastic were the cause of death of one of 45 Laysan Albatross chicks examined in 1986, but were not the cause of death of 93 individuals examined in 1987. Dehydration was the most common cause of death. In general, ingested plastic was not a significant direct cause of death in nestlings, but there was some evidence that it may have affected survival in 1986, when the volume of plastic ingested was highest.

The complete process of large elastic-plastic deflection of a cantilever

NASA Astrophysics Data System (ADS)

Wu, Xiaoqiang; Yu, Tongxi

1986-11-01

An extension of the Elastica theory is developed to study the large deflection of an elastic-perfectly plastic horizontal cantilever beam subjected to a vertical concentrated force at its tip. The entire process is divided into four stages: I.elastic in the whole cantilever; II.loading and developing of the plastic region; III.unloading in the plastic region; and IV.reverse loading. Solutions for stages I and II are presented in a closed form. A combination of closed-form solution and numerical integration is presented for stage III. Finally, stage IV is qualitatively studied. Computed results are given and compared with those from small-deflection theory and from the Elastica theory.

High-frequency cortical subdural stimulation enhanced plasticity in surgery of a tumor in Broca's area.

PubMed

Barcia, Juan A; Sanz, Ana; Balugo, Paloma; Alonso-Lera, Pedro; Brin, Juan Raúl; Yus, Miguel; Gonzalez-Hidalgo, Mercedes; Acedo, Victoria M; Oliviero, Antonio

2012-03-28

Functional areas located near or within brain gliomas prevent the complete resection of these tumors. It has recently been described that slow tumor invasion promotes neural reorganization, and even topographic plasticity, allowing a staged resection of those tumors. Thus, our aim was to promote plasticity by mimicking the tumor's capability to displace brain function. This proceeded through the production of a 'virtual lesion' in eloquent areas within a tumor using continuous high-frequency cortical electrical stimulation (cHFCS). An anaplastic astrocytoma located in Broca's area progressed in a patient whose lateralization of language to the side of the lesion was demonstrated with functional MRI. After partial tumor resection using awake cortical monitoring, we implanted a subdural grid over the eloquent cortex located within residual tumor. We then applied cHFCS for 25 days, using a frequency of 130 Hz and a pulse width of 1 ms. Stimulus intensity was set to the threshold wherein mild speech disturbance was evident without any other neurological effects. This treatment successfully achieved the displacement of speech functions, and a more radical resection of the tumor was possible in a second surgery. Critically, a reorganization of motor language areas was demonstrated both with functional MRI and cortical stimulation. Furthermore, motor language areas were also identified in the right hemisphere, where previously they were absent. The patient's speech fluency improved both after stimulation and resection. We therefore demonstrate the first evidence of induced topographic plasticity using cHFCS in eloquent areas within a tumor, which allowed for increased tumor removal. Our results open the possibility to induce plasticity before the resection of brain tumors near eloquent areas, in order to increase the extent of resection.

Effect of reduction of area on microstructure and mechanical properties of twinning-induced plasticity steel during wire drawing

NASA Astrophysics Data System (ADS)

Hwang, Joong-Ki; Son, Il-Heon; Yoo, Jang-Yong; Zargaran, A.; Kim, Nack J.

2015-09-01

The effect of reduction of area (RA), 10%, 20%, and 30%, during wire drawing on the inhomogeneities in microstructure and mechanical properties along the radial direction of Fe-Mn-Al-C twinning-induced plasticity steel has been investigated. After wire drawing, the deformation texture developed into the major <111> and minor <100> duplex fiber texture. However, the <111> texture became more pronounced in both center and surface areas as the RA per pass increased. It also shows that a larger RA per pass resulted in a higher yield strength and smaller elongation than a smaller RA per pass at all strain levels. Although inhomogeneities in microstructure and mechanical properties along the radial direction decreased with increasing RA per pass, there existed an optimum RA per pass for maximum drawing limit. Insufficient penetration of strain from surface to center at small RA per pass (e.g., 10%) and high friction and unsound metal flow at large RA per pass (e.g., 30%) all resulted in heterogeneous microstructure and mechanical properties along the radial direction of drawn wire. On the other hand, 20% RA per pass improved the drawing limit by about 30% as compared to the 10% and 30% RAs per pass.

Soil sampling and analytical strategies for mapping fallout in nuclear emergencies based on the Fukushima Dai-ichi Nuclear Power Plant accident.

PubMed

Onda, Yuichi; Kato, Hiroaki; Hoshi, Masaharu; Takahashi, Yoshio; Nguyen, Minh-Long

2015-01-01

The Fukushima Dai-ichi Nuclear Power Plant (FDNPP) accident resulted in extensive radioactive contamination of the environment via deposited radionuclides such as radiocesium and (131)I. Evaluating the extent and level of environmental contamination is critical to protecting citizens in affected areas and to planning decontamination efforts. However, a standardized soil sampling protocol is needed in such emergencies to facilitate the collection of large, tractable samples for measuring gamma-emitting radionuclides. In this study, we developed an emergency soil sampling protocol based on preliminary sampling from the FDNPP accident-affected area. We also present the results of a preliminary experiment aimed to evaluate the influence of various procedures (e.g., mixing, number of samples) on measured radioactivity. Results show that sample mixing strongly affects measured radioactivity in soil samples. Furthermore, for homogenization, shaking the plastic sample container at least 150 times or disaggregating soil by hand-rolling in a disposable plastic bag is required. Finally, we determined that five soil samples within a 3 m × 3-m area are the minimum number required for reducing measurement uncertainty in the emergency soil sampling protocol proposed here. Copyright © 2014 Elsevier Ltd. All rights reserved.

75 FR 10414 - Researcher Identification Card

Federal Register 2010, 2011, 2012, 2013, 2014

2010-03-08

... capturing administrative information on the characteristics of our users. Other forms of identification are... use bar-codes on researcher identification cards in the Washington, DC, area. The plastic cards we... plastic researcher identification cards as part of their security systems, we issue a plastic card to...

Polybrominated diphenyl ethers in soils, sediments, and human hair in a plastic waste recycling area: a neglected heavily polluted area.

PubMed

Tang, Zhenwu; Huang, Qifei; Cheng, Jiali; Yang, Yufei; Yang, Jun; Guo, Wei; Nie, Zhiqiang; Zeng, Ning; Jin, Lu

2014-01-01

The release of pollutants during the recycling of contaminated plastics is a problem which has drawn worldwide attention; however, little information on the transfer of polybrominated diphenyl ethers (PBDEs) in these processes is available. We conducted a survey of PBDEs in soils, sediments, and human hair in a typical plastic waste recycling area in northern China. The total concentrations (ng/g) of 21 PBDEs were 1.25-5504 (average 600), 18.2-9889 (average 1619), and 1.50-861 (average 112) in soils, sediments, and hair, respectively. The PBDE concentrations were comparable to concentrations observed in e-waste recycling areas; however, the concentrations in soils and sediments were 1-3 orders of magnitude higher than in other areas, and the concentrations in hair were much higher than in other areas. This indicates that this area is highly polluted with PBDEs. BDE-209 was the dominant congener (representing 91.23%, 92.3%, and 91.5% of the total PBDEs observed in soils, sediments, and hair, respectively), indicating that the commercial deca-BDE product was dominant. The commercial penta- and octa-BDE products made small contributions to the total PBDE concentrations, unlike what has been found in some e-waste recycling areas. Our results show that crude plastic waste processing is a major contributor of PBDEs to the environment and humans, which should be of great concern.

Qualitative assessment to determine internal and external factors influencing the origin of styrene oligomers pollution by polystyrene plastic in coastal marine environments.

PubMed

Kwon, Bum Gun; Chung, Seon-Yong; Park, Seung-Shik; Saido, Katsuhiko

2018-03-01

The objective of this study is to investigate the qualitative contribution of internal and external factors of the area contaminated by polystyrene (PS) in coastal marine environments. This study is based on the extensive results of monitoring the styrene oligomers (SOs) present in sand and seawater samples along various coastlines of the Pacific Ocean. Here, anthropogenic SOs is derived from PS during manufacture and use, and can provide clues about the origin of SOs by PS pollution. The monitoring results showed that, if the concentration of SOs in water is higher than those concentrations in beach sand, this area could be affected by PS plastic caused by an external factor. On the other hand, if the concentration of SOs is higher in the beach sand, the region can be mainly influenced by PS plastic derived from its own area. Unlike the case of an external factor, in this case (internal influence), it is possible to take policy measures of the area itself for the PS plastic problem. Thus, this study is motivated by the need of policy measures to establish a specific alternative to the problems of PS plastic pollution in ocean environments. Copyright © 2017 Elsevier Ltd. All rights reserved.

A Lesson Plan to Develop Structured Discussion of the Benefits and Disadvantages of Selected Plastics Using the Product-Testing Method

ERIC Educational Resources Information Center

Burmeister, Mareike; Eilks, Ingo

2014-01-01

People use many different products made from plastics every day. But conventional plastics such as polyvinyl chloride (PVC) do not always have a good reputation in society at large. Bioplastics such as thermoplastic starch (TPS) promise to be better alternatives but are they really better than conventional plastics? This article presents a new…

Evidence that the Great Pacific Garbage Patch is rapidly accumulating plastic.

PubMed

Lebreton, L; Slat, B; Ferrari, F; Sainte-Rose, B; Aitken, J; Marthouse, R; Hajbane, S; Cunsolo, S; Schwarz, A; Levivier, A; Noble, K; Debeljak, P; Maral, H; Schoeneich-Argent, R; Brambini, R; Reisser, J

2018-03-22

Ocean plastic can persist in sea surface waters, eventually accumulating in remote areas of the world's oceans. Here we characterise and quantify a major ocean plastic accumulation zone formed in subtropical waters between California and Hawaii: The Great Pacific Garbage Patch (GPGP). Our model, calibrated with data from multi-vessel and aircraft surveys, predicted at least 79 (45-129) thousand tonnes of ocean plastic are floating inside an area of 1.6 million km 2 ; a figure four to sixteen times higher than previously reported. We explain this difference through the use of more robust methods to quantify larger debris. Over three-quarters of the GPGP mass was carried by debris larger than 5 cm and at least 46% was comprised of fishing nets. Microplastics accounted for 8% of the total mass but 94% of the estimated 1.8 (1.1-3.6) trillion pieces floating in the area. Plastic collected during our study has specific characteristics such as small surface-to-volume ratio, indicating that only certain types of debris have the capacity to persist and accumulate at the surface of the GPGP. Finally, our results suggest that ocean plastic pollution within the GPGP is increasing exponentially and at a faster rate than in surrounding waters.

ThermoYield actuators: nano-adjustable set-and-forget optics mounts

NASA Astrophysics Data System (ADS)

DeTienne, Michael D.; Bruccoleri, Alexander R.; Chalifoux, Brandon; Heilmann, Ralf K.; Tedesco, Ross E.; Schattenburg, Mark L.

2017-08-01

The X-ray optics community has been developing technology for high angular resolution, large collecting area X-ray telescopes such as the Lynx X-ray telescope concept. To meet the high collecting area requirements of such telescope concepts, research is being conducted on thin, segmented optics. The mounts that fixture and align segmented optics must be the correct length to sub-micron accuracy to satisfy the angular resolution goals of such a concept. Set-andforget adjustable length optical mounting posts have been developed to meet this need. The actuator consists of a cylinder made of metal. Halfway up the height of the metal cylinder, a reduced diameter cylindrical neck is cut. To change the length of this actuator, an axial compressive or tensile force is applied to the actuator. A high-current electrical pulse is sent through the actuator, and this electrical current resistively heats the neck of the actuator. This heating temporarily reduces the yield strength of the neck, so that the applied force plastically deforms the neck. Once the current stops and the neck cools, the neck will regain yield strength, and the plastic deformation will stop. All of the plastic deformation that occurred during heating is now permanent. Both compression and expansion of these actuators has been demonstrated in steps ranging from 6 nanometers to several microns. This paper will explain the concept of ThermoYield actuation, explore X-ray telescope applications, describe an experimental setup, show and discuss data, and propose future ideas.

Fuels from pyrolysis of waste plastic

USDA-ARS?s Scientific Manuscript database

A large quantity of carbon containing materials, such as waste plastic, used tires, food waste, and biomass end up in landfills. These materials represent a rich energy source that is currently untapped or underutilized. Municipal solid waste is comprised of 12% waste plastic, but only a small fract...

High axial resolution imaging system for large volume tissues using combination of inclined selective plane illumination and mechanical sectioning

PubMed Central

Zhang, Qi; Yang, Xiong; Hu, Qinglei; Bai, Ke; Yin, Fangfang; Li, Ning; Gang, Yadong; Wang, Xiaojun; Zeng, Shaoqun

2017-01-01

To resolve fine structures of biological systems like neurons, it is required to realize microscopic imaging with sufficient spatial resolution in three dimensional systems. With regular optical imaging systems, high lateral resolution is accessible while high axial resolution is hard to achieve in a large volume. We introduce an imaging system for high 3D resolution fluorescence imaging of large volume tissues. Selective plane illumination was adopted to provide high axial resolution. A scientific CMOS working in sub-array mode kept the imaging area in the sample surface, which restrained the adverse effect of aberrations caused by inclined illumination. Plastic embedding and precise mechanical sectioning extended the axial range and eliminated distortion during the whole imaging process. The combination of these techniques enabled 3D high resolution imaging of large tissues. Fluorescent bead imaging showed resolutions of 0.59 μm, 0.47μm, and 0.59 μm in the x, y, and z directions, respectively. Data acquired from the volume sample of brain tissue demonstrated the applicability of this imaging system. Imaging of different depths showed uniform performance where details could be recognized in either the near-soma area or terminal area, and fine structures of neurons could be seen in both the xy and xz sections. PMID:29296503

Composite rotor blades for large wind energy installations

NASA Technical Reports Server (NTRS)

Kussmann, A.; Molly, J.; Muser, D.

1980-01-01

The design of large wind power systems in Germany is reviewed with attention given to elaboration of the total wind energy system, aerodynamic design of the rotor blade, and wind loading effects. Particular consideration is given to the development of composite glass fiber/plastic or carbon fiber/plastic rotor blades for such installations.

Sinuous Flow in Cutting of Metals

NASA Astrophysics Data System (ADS)

Yeung, Ho; Viswanathan, Koushik; Udupa, Anirudh; Mahato, Anirban; Chandrasekar, Srinivasan

2017-11-01

Using in situ high-speed imaging, we unveil details of a highly unsteady plastic flow mode in the cutting of annealed and highly strain-hardening metals. This mesoscopic flow mode, termed sinuous flow, is characterized by repeated material folding, large rotation, and energy dissipation. Sinuous flow effects a very large shape transformation, with local strains of ten or more, and results in a characteristic mushroomlike surface morphology that is quite distinct from the well-known morphologies of metal-cutting chips. Importantly, the attributes of this unsteady flow are also fundamentally different from other well-established unsteady plastic flows in large-strain deformation, like adiabatic shear bands. The nucleation and development of sinuous flow, its dependence on material properties, and its manifestation across material systems are demonstrated. Plastic buckling and grain-scale heterogeneity are found to play key roles in triggering this flow at surfaces. Implications for modeling and understanding flow stability in large-strain plastic deformation, surface quality, and preparation of near-strain-free surfaces by cutting are discussed. The results point to the inadequacy of the widely used shear-zone models, even for ductile metals.

Ingested plastic transfers hazardous chemicals to fish and induces hepatic stress

PubMed Central

Rochman, Chelsea M.; Hoh, Eunha; Kurobe, Tomofumi; Teh, Swee J.

2013-01-01

Plastic debris litters aquatic habitats globally, the majority of which is microscopic (< 1 mm), and is ingested by a large range of species. Risks associated with such small fragments come from the material itself and from chemical pollutants that sorb to it from surrounding water. Hazards associated with the complex mixture of plastic and accumulated pollutants are largely unknown. Here, we show that fish, exposed to a mixture of polyethylene with chemical pollutants sorbed from the marine environment, bioaccumulate these chemical pollutants and suffer liver toxicity and pathology. Fish fed virgin polyethylene fragments also show signs of stress, although less severe than fish fed marine polyethylene fragments. We provide baseline information regarding the bioaccumulation of chemicals and associated health effects from plastic ingestion in fish and demonstrate that future assessments should consider the complex mixture of the plastic material and their associated chemical pollutants. PMID:24263561

Development of a Fatigue Crack Growth Coupon for Highly Plastic Stress Conditions

NASA Technical Reports Server (NTRS)

Allen, Phillip A.; Aggarwal, Pravin K.; Swanson, Gregory R.

2003-01-01

The analytical approach used to develop a novel fatigue crack growth coupon for highly plastic stress field condition is presented in this paper. The flight hardware investigated is a large separation bolt that has a deep notch, which produces a large plastic zone at the notch root when highly loaded. Four test specimen configurations are analyzed in an attempt to match the elastic-plastic stress field and crack constraint conditions present in the separation bolt. Elastic-plastic finite element analysis is used to compare the stress fields and critical fracture parameters. Of the four test specimens analyzed, the modified double-edge notch tension - 3 (MDENT-3) most closely approximates the stress field, J values, and crack constraint conditions found in the flight hardware. The MDENT-3 is also most insensitive to load misalignment and/or load redistribution during crack growth.

Observation of cosmic-ray particles with Z of 50 or greater and interpretation of the charge spectrum.

NASA Technical Reports Server (NTRS)

Blanford, G. E., Jr.; Friedlander, M. W.; Klarmann, J.; Walker, R. M.; Wefel, J. P.

1973-01-01

Large areas of plastic detectors and nuclear emulsions were exposed to the primary cosmic radiation on two high-altitude balloon flights in May 1968 and September 1969. From measurements on the tracks found in the scanning of the plastic detectors, events with charges Z greater than 50 were selected, and these data were consolidated with those from our earlier flights. Several conclusions can be drawn from the observed charge spectrum. The detection of trans-bismuth nuclei confirms earlier observations of these particles in the cosmic rays. However, no trans-uranium particles were observed. Detailed features of the charge spectrum cannot be explained by nuclei from r-process nucleosynthesis alone. Although the addition of particles following s-process abundances yields improved agreement, the spectrum appears more complicated than would result from a simple combination of r- and s-process abundances with identical propagation histories.

Survey of reconstructive microsurgery training in Korea.

PubMed

Moon, Seong June; Hong, Joon Pio; Kang, So Ra; Suh, Hyun Suk

2015-01-01

Microsurgical technique in reconstructive surgery is important. Despite recognizing this fact, there are no systematized microsurgery training programs in Korea. The purpose of this study was to diagnose the current training programs and discuss the direction that is needed to improve them. The authors conducted a survey of graduates of a plastic surgery residency program. The questionnaire included the volume of microsurgery, training environment, area of microsurgery, department(s) performing microsurgery, and the frequency with which flaps were used. Many specialties other than plastic surgery involved microsurgical procedures. The volume of microsurgery cases was disproportionate between large and small hospitals, creating an imbalance of residents' experience with microsurgical procedures. The increase in microsurgical procedures being performed has increased the number of surgeons who want to train in microsurgery. Increasing the number of microsurgery training programs will create more microsurgeons in Korea. Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

Long-term potentiation expands information content of hippocampal dentate gyrus synapses.

PubMed

Bromer, Cailey; Bartol, Thomas M; Bowden, Jared B; Hubbard, Dusten D; Hanka, Dakota C; Gonzalez, Paola V; Kuwajima, Masaaki; Mendenhall, John M; Parker, Patrick H; Abraham, Wickliffe C; Sejnowski, Terrence J; Harris, Kristen M

2018-03-06

An approach combining signal detection theory and precise 3D reconstructions from serial section electron microscopy (3DEM) was used to investigate synaptic plasticity and information storage capacity at medial perforant path synapses in adult hippocampal dentate gyrus in vivo. Induction of long-term potentiation (LTP) markedly increased the frequencies of both small and large spines measured 30 minutes later. This bidirectional expansion resulted in heterosynaptic counterbalancing of total synaptic area per unit length of granule cell dendrite. Control hemispheres exhibited 6.5 distinct spine sizes for 2.7 bits of storage capacity while LTP resulted in 12.9 distinct spine sizes (3.7 bits). In contrast, control hippocampal CA1 synapses exhibited 4.7 bits with much greater synaptic precision than either control or potentiated dentate gyrus synapses. Thus, synaptic plasticity altered total capacity, yet hippocampal subregions differed dramatically in their synaptic information storage capacity, reflecting their diverse functions and activation histories.

Career development resource for plastic and reconstructive surgery.

PubMed

Walden, Jennifer L; Phillips, Linda G

2010-02-01

Plastic surgery is a broad-based discipline with emphasis on areas such as breast, craniomaxillofacial, burn, aesthetic, and hand surgery as well as complex wounds and wound healing. Plastic surgery as a specialty captures a great deal of media attention over many other fields of medicine, so education, training, and credentialing have become an area of national interest. The purpose of this article was to provide information on the organization, basic requirements for training, fellowship, and volunteer opportunities within the specialty. Copyright 2010 Elsevier Inc. All rights reserved.

Methods of Passing Vehicles Over Areas Similar in Character to Rice Paddy Fields

DTIC Science & Technology

1945-01-02

Test Branch in specially prepared mud areas, some of which had been planted with rice and hemp . 3. From these and previous tests it is concluded in...0.005m). The Liquid Limit was 21j Plastic Limit, 16j Plasticity Index, 6. The test areas are listed as follows» a. One area 100 by 300...feet prepared for immediate use far "go - no go" tests. b. Twe areas 90 by 210 feet each, one planted with rice and the other planted with hemp , for

Gamma Ray Large Area Space Telescope (GLAST) Balloon Flight Engineering Model: Overview

NASA Technical Reports Server (NTRS)

Thompson, D. J.; Godfrey, G.; Williams, S. M.; Grove, J. E.; Mizuno, T.; Sadrozinski, H. F.-W.; Kamae, T.; Ampe, J.; Briber, Stuart; Dann, James;

Technology development of high-quality semiconductor devices using solution-processed crystallization of pentacene

NASA Astrophysics Data System (ADS)

Liu, Hung-Wei

Organic electronic materials and processing techniques have attracted considerable attention for developing organic thin-film transistors (OTFTs), since they may be patterned on flexible substrates which may be bent into a variety of shapes for applications such as displays, smart cards, solar devices and sensors Various fabrication methods for building pentacene-based OTFTs have been demonstrated. Traditional vacuum deposition and vapor deposition methods have been studied for deposition on plastic and paper, but these are unlikely to scale well to large area printing. Researchers have developed methods for processing OTFTs from solution because of the potential for low-cost and large area device manufacturing, such as through inkjet or offset printing. Most methods require the use of precursors which are used to make pentacene soluble, and these methods have typically produced much lower carrier mobility than the best vacuum deposited devices. We have investigated devices built from solution-processed pentacene that is locally crystallized at room temperature on the polymer substrates. Pentacene crystals grown in this manner are highly localized at pre-determined sites, have good crystallinity and show good carrier mobility, making this an attractive method for large area manufacturing of semiconductor devices.

Benthic marine debris, with an emphasis on fishery-related items, surrounding Kodiak Island, Alaska, 1994-1996

USGS Publications Warehouse

Hess, N.A.; Ribic, C.A.; Vining, I.

1999-01-01

Composition and abundance of benthic marine debris were investigated during three bottom trawl surveys in inlet and offshore locations surrounding Kodiak Island, Alaska, 1994-1996. Debris items were primarily plastic and metal regardless of trawl location. Plastic bait jars, fishing line, and crab pots were the most common fishery-related debris items and were encountered in large amounts in inlets (20-25 items km-2), but were less abundant outside of inlets (4.5-11 items km-2). Overall density of debris was also significantly greater in inlets than outside of inlets. Plastic debris densities in inlets ranged 22-31.5 items km-2, 7.8-18.8 items km-2 outside of inlets. Trawls in inlets contained almost as much metal debris as plastic debris. Density of metal debris ranged from 21.2 to 23.7 items km-2 in inlets, a maximum of 2.7 items km-2 outside of inlets. Inlets around the town of Kodiak had the highest densities of fishery-related and total benthic debris. Differences in benthic debris density between inlets and outside of inlets and differences by area may be due to differences in fishing activity and water circulation patterns. At the current reduced levels of fishing activity, however, yearly monitoring of benthic debris appears unnecessary. Copyright (C) 1999.

Phenotypic plasticity in the spawning traits of bigheaded carp (Hypophthalmichthys spp.) in novel ecosystems

USGS Publications Warehouse

Coulter, Alison A.; Keller, Doug; Amberg, Jon J.; Bailey, Elizabeth J.; Goforth, Reuben R.

2013-01-01

1. Bigheaded carp, including both silver (Hypophthalmichthys molitrix) and bighead (H. nobilis) carp, are successful invasive fishes that threaten global freshwater biodiversity. High phenotypic plasticity probably contributes to their success in novel ecosystems, although evidence of plasticity in several spawning traits has hitherto been largely anecdotal or speculative. 2. We collected drifting eggs from a Midwestern U.S.A. river from June to September 2011 and from April to June 2012 to investigate the spawning traits of bigheaded carp in novel ecosystems. 3. Unlike reports from the native range, the presence of drifting bigheaded carp eggs was not related to changes in hydrological regime or mean daily water temperature. Bigheaded carp also exhibited protracted spawning, since we found drifting eggs throughout the summer and as late as 1 September 2011. Finally, we detected bigheaded carp eggs in a river reach where the channel is c. 30 m wide with a catchment area of 4579 km2, the smallest stream in which spawning has yet been documented. 4. Taken with previous observations of spawning traits that depart from those observed within the native ranges of both bighead and silver carp, our findings provide direct evidence that bigheaded carp exhibit plastic spawning traits in novel ecosystems that may facilitate invasion and establishment in a wider range of river conditions than previously envisaged.

Floating plastic debris in the Central and Western Mediterranean Sea.

PubMed

Ruiz-Orejón, Luis F; Sardá, Rafael; Ramis-Pujol, Juan

2016-09-01

In two sea voyages throughout the Mediterranean (2011 and 2013) that repeated the historical travels of Archduke Ludwig Salvator of Austria (1847-1915), 71 samples of floating plastic debris were obtained with a Manta trawl. Floating plastic was observed in all the sampled sites, with an average weight concentration of 579.3 g dw km(-2) (maximum value of 9298.2 g dw km(-2)) and an average particle concentration of 147,500 items km(-2) (the maximum concentration was 1,164,403 items km(-2)). The plastic size distribution showed microplastics (<5 mm) in all the samples. The most abundant particles had a surface area of approximately 1 mm(2) (the mesh size was 333 μm). The general estimate obtained was a total value of 1455 tons dw of floating plastic in the entire Mediterranean region, with various potential spatial accumulation areas. Copyright © 2016 Elsevier Ltd. All rights reserved.

77 FR 58953 - Approval and Promulgation of Air Quality Implementation Plans; Delaware; Control Technique...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-09-25

... Promulgation of Air Quality Implementation Plans; Delaware; Control Technique Guidelines for Plastic Parts... categories: Plastic Parts, Metal Furniture, Large Appliances, and Miscellaneous Metal Parts. EPA is approving... Compounds, sections 2.0 ``Definitions,'' 12.0 ``Surface Coating of Plastic Parts,'' 19.0 ``Coating of Metal...

77 FR 19537 - MARPOL Annex V Special Areas: Wider Caribbean Region

Federal Register 2010, 2011, 2012, 2013, 2014

2012-04-02

... through section 2101 of the Marine Plastic Pollution Research and Control Act (Pub. L. 100-220). MARPOL... in increased burdens to vessels or reception facilities. One commenter brought up the problem of dry... the following types: Plastics, including synthetic ropes, fishing nets, and plastic bags; Dunnage (i.e...

Fluoxetine increases plasticity and modulates the proteomic profile in the adult mouse visual cortex

PubMed Central

Ruiz-Perera, L.; Muniz, M.; Vierci, G.; Bornia, N.; Baroncelli, L.; Sale, A.; Rossi, F.M.

2015-01-01

The scarce functional recovery of the adult CNS following injuries or diseases is largely due to its reduced potential for plasticity, the ability to reorganize neural connections as a function of experience. Recently, some new strategies restoring high levels of plasticity in the adult brain have been identified, especially in the paradigmatic model of the visual system. A chronic treatment with the anti-depressant fluoxetine reinstates plasticity in the adult rat primary visual cortex, inducing recovery of vision in amblyopic animals. The molecular mechanisms underlying this effect remain largely unknown. Here, we explored fluoxetine effects on mouse visual cortical plasticity, and exploited a proteomic approach to identify possible candidates mediating the outcome of the antidepressant treatment on adult cortical plasticity. We showed that fluoxetine restores ocular dominance plasticity in the adult mouse visual cortex, and identified 31 differentially expressed protein spots in fluoxetine-treated animals vs. controls. MALDITOF/TOF mass spectrometry identification followed by bioinformatics analysis revealed that these proteins are involved in the control of cytoskeleton organization, endocytosis, molecular transport, intracellular signaling, redox cellular state, metabolism and protein degradation. Altogether, these results indicate a complex effect of fluoxetine on neuronal signaling mechanisms potentially involved in restoring plasticity in the adult brain. PMID:26205348

Synaptic plasticity in the hippocampal area CA1-subiculum projection: implications for theories of memory.

PubMed

O'Mara, S M; Commins, S; Anderson, M

2000-01-01

This paper reviews investigations of synaptic plasticity in the major, and underexplored, pathway from hippocampal area CA1 to the subiculum. This brain area is the major synaptic relay for the majority of hippocampal area CA1 neurons, making the subiculum the last relay of the hippocampal formation prior to the cortex. The subiculum thus has a very major role in mediating hippocampal-cortical interactions. We demonstrate that the projection from hippocampal area CA1 to the subiculum sustains plasticity on a number of levels. We show that this pathway is capable of undergoing both long-term potentiation (LTP) and paired-pulse facilitation (PPF, a short-term plastic effect). Although we failed to induce long-term depression (LTD) of this pathway with low-frequency stimulation (LFS) and two-pulse stimulation (TPS), both protocols can induce a "late-developing" potentiation of synaptic transmission. We further demonstrate that baseline synaptic transmission can be dissociated from paired-pulse stimulation of the same pathway; we also show that it is possible, using appropriate protocols, to change PPF to paired-pulse depression, thus revealing subtle and previously undescribed mechanisms which regulate short-term synaptic plasticity. Finally, we successfully recorded from individual subicular units in the freely-moving animal, and provide a description of the characteristics of such neurons in a pellet-chasing task. We discuss the implications of these findings in relation to theories of the biological consolidation of memory.

Differences in functional traits between invasive and native Amaranthus species under different forms of N deposition

NASA Astrophysics Data System (ADS)

Wang, Congyan; Zhou, Jiawei; Liu, Jun; Jiang, Kun

2017-08-01

Differences in functional traits between invasive and native plant species are believed to determine the invasion success of the former. Increasing amounts of anthropogenic nitrogen (N) are continually deposited into natural ecosystems, which may change the relative occurrence of the different N deposition forms (such as NH4-N, NO3-N, and CO(NH2)2-N) naturally deposited. Under high N deposition scenarios, some invasive species may grow faster, gaining advantage over native species. In a greenhouse experiment, we grew invasive and native Amaranthus species from seed both alone and in competition under simulated N enriched environments with different forms of N over 3 months. Then, we measured different leaf traits (i.e., plant height, leaf length, leaf width, leaf shape index, specific leaf area (SLA), and leaf chlorophyll and N concentrations). Results showed that the competition intensity between A. retroflexus and A. tricolor decreased under N deposition. This may be due to the large functional divergence between A. retroflexus and A. tricolor under simulated N deposition. Phenotypic plasticity of SLA and leaf chlorophyll concentration of A. retroflexus were significantly lower than in A. tricolor. The lower range of phenotypic plasticity of SLA and leaf chlorophyll concentration of A. retroflexus may indicate a fitness cost for plastic functional traits under adverse environments. The restricted phenotypic plasticity of SLA and leaf chlorophyll concentration of A. retroflexus may also stabilize leaf construction costs and the growth rate. Meanwhile, the two Amaranthus species possessed greater plasticity in leaf N concentration under NO3-N fertilization, which enhanced their competitiveness.

Differences in functional traits between invasive and native Amaranthus species under different forms of N deposition.

PubMed

Wang, Congyan; Zhou, Jiawei; Liu, Jun; Jiang, Kun

2017-08-01

Differences in functional traits between invasive and native plant species are believed to determine the invasion success of the former. Increasing amounts of anthropogenic nitrogen (N) are continually deposited into natural ecosystems, which may change the relative occurrence of the different N deposition forms (such as NH 4 -N, NO 3 -N, and CO(NH 2 ) 2 -N) naturally deposited. Under high N deposition scenarios, some invasive species may grow faster, gaining advantage over native species. In a greenhouse experiment, we grew invasive and native Amaranthus species from seed both alone and in competition under simulated N enriched environments with different forms of N over 3 months. Then, we measured different leaf traits (i.e., plant height, leaf length, leaf width, leaf shape index, specific leaf area (SLA), and leaf chlorophyll and N concentrations). Results showed that the competition intensity between A. retroflexus and A. tricolor decreased under N deposition. This may be due to the large functional divergence between A. retroflexus and A. tricolor under simulated N deposition. Phenotypic plasticity of SLA and leaf chlorophyll concentration of A. retroflexus were significantly lower than in A. tricolor. The lower range of phenotypic plasticity of SLA and leaf chlorophyll concentration of A. retroflexus may indicate a fitness cost for plastic functional traits under adverse environments. The restricted phenotypic plasticity of SLA and leaf chlorophyll concentration of A. retroflexus may also stabilize leaf construction costs and the growth rate. Meanwhile, the two Amaranthus species possessed greater plasticity in leaf N concentration under NO 3 -N fertilization, which enhanced their competitiveness.

Monitoring the abundance of plastic debris in the marine environment.

PubMed

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

2009-07-27

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. Infrequent surveys of the standing stock of litter on beaches provide crude estimates of debris types and abundance, but are biased by differential removal of litter items by beachcombing, cleanups and beach dynamics. Monitoring the accumulation of stranded debris provides an index of debris trends in adjacent waters, but is costly to undertake. At-sea sampling requires large sample sizes for statistical power to detect changes in abundance, given the high spatial and temporal heterogeneity. Another approach is to monitor the impacts of plastics. Seabirds and other marine organisms that accumulate plastics in their stomachs offer a cost-effective way to monitor the abundance and composition of small plastic litter. Changes in entanglement rates are harder to interpret, as they are sensitive to changes in population sizes of affected species. Monitoring waste disposal on ships and plastic debris levels in rivers and storm-water runoff is useful because it identifies the main sources of plastic debris entering the sea and can direct mitigation efforts. Different monitoring approaches are required to answer different questions, but attempts should be made to standardize approaches internationally.

Monitoring the abundance of plastic debris in the marine environment

PubMed Central

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. Infrequent surveys of the standing stock of litter on beaches provide crude estimates of debris types and abundance, but are biased by differential removal of litter items by beachcombing, cleanups and beach dynamics. Monitoring the accumulation of stranded debris provides an index of debris trends in adjacent waters, but is costly to undertake. At-sea sampling requires large sample sizes for statistical power to detect changes in abundance, given the high spatial and temporal heterogeneity. Another approach is to monitor the impacts of plastics. Seabirds and other marine organisms that accumulate plastics in their stomachs offer a cost-effective way to monitor the abundance and composition of small plastic litter. Changes in entanglement rates are harder to interpret, as they are sensitive to changes in population sizes of affected species. Monitoring waste disposal on ships and plastic debris levels in rivers and storm-water runoff is useful because it identifies the main sources of plastic debris entering the sea and can direct mitigation efforts. Different monitoring approaches are required to answer different questions, but attempts should be made to standardize approaches internationally. PMID:19528052

Plastics in the marine environment: the dark side of a modern gift.

PubMed

Hammer, Jort; Kraak, Michiel H S; Parsons, John R

2012-01-01

Plastics are cheap, strong, and durable and offer considerable benefits to humanity. They potentially can enhance the benefits that both medical and scientific technology will bestow to humankind. However, it has now been several decades since the use of plastics exploded, and we have evidence that our current approach to production, use, transport and disposal of plastic materials has caused, and is still causing serious effects on wildlife, and is not sustainable. Because of frequent inappropriate waste management practices, or irresponsible human behavior, large masses of plastic items have been released into the environment, and thereby have entered the world's oceans. Moreover, this process continues, and in some places is even increasing. Most plastic debris that now exists in the marine environment originated from ocean-based sources such as the fishing industry. Plastics accumulate in coastal areas, at the ocean surface and on the seabed. Because 70% of all plastics are known to eventually sink, it is suspected that ever increasing amounts of plastic items are accumulating in seabed sediments. Plastics do not biodegrade, although, under the influence of solar UV radiations, plastics do degrade and fragment into small particles, termed microplastics. Our oceans eventually serve as a sink for these small plastic particles and in one estimate, it is thought that 200,000 microplastics per km(2) of the ocean's surface commonly exist. The impact of plastic debris has been studied since the beginning of the 1960's. To date, more than 267 species in the marine environment are known to have been affected by plastic entanglement or ingestion. Marine mammals are among those species that are most affected by entanglement in plastic debris. By contrast, marine birds suffer the most from ingestion of plastics. Organisms can also be seriously absorbed by floating plastic debris, or the contaminants may derive from plastic additives that are leached to the environment. Recent studies emphasize the important role of microplastics as they are easily ingestible by small organisms, such as plankton species, and form a pathway for contaminants to enter the food web. Contaminants leached from plastics tend to bioaccumulate in those organisms that absorb them, and chemical concentrations are often higher at higher trophic levels. This causes a threat to the basis of every food web and can have serious and far-reaching effects, even on nonmarine species such as polar bears and humans, who consume marine-grown food. Therefore, resolving the plastic debris problem is important to human kind for two reasons: we are both creator, and victim of the plastic pollution problem. Solutions to the plastic debris problem can only be achieved through a combination of actions. Such actions include the following: Legislation against marine pollution by plastics must be enforced, recycling must be accentuated, alternatives (biodegradable) to current plastic products must be found, and clean-up of debris must proceed, if the marine plastic pollution problem is to eventually be resolved. Governments cannot accomplish this task on their own, and will need help and initiative from the public. Moreover, resolving this long-standing problem will require time, money, and energy from many individuals now living and those of future generations, if a safer and cleaner marine environment is to be achieved.

Finite element analysis of large transient elastic-plastic deformations of simple structures, with application to the engine rotor fragment containment/deflection problem

NASA Technical Reports Server (NTRS)

Wu, R. W.; Witmer, E. A.

1972-01-01

Assumed-displacement versions of the finite-element method are developed to predict large-deformation elastic-plastic transient deformations of structures. Both the conventional and a new improved finite-element variational formulation are derived. These formulations are then developed in detail for straight-beam and curved-beam elements undergoing (1) Bernoulli-Euler-Kirchhoff or (2) Timoshenko deformation behavior, in one plane. For each of these categories, several types of assumed-displacement finite elements are developed, and transient response predictions are compared with available exact solutions for small-deflection, linear-elastic transient responses. The present finite-element predictions for large-deflection elastic-plastic transient responses are evaluated via several beam and ring examples for which experimental measurements of transient strains and large transient deformations and independent finite-difference predictions are available.

All is not lost: deriving a top-down mass budget of plastic at sea

NASA Astrophysics Data System (ADS)

Koelmans, Albert A.; Kooi, Merel; Lavender Law, Kara; van Sebille, Erik

2017-11-01

Understanding the global mass inventory is one of the main challenges in present research on plastic marine debris. Especially the fragmentation and vertical transport processes of oceanic plastic are poorly understood. However, whereas fragmentation rates are unknown, information on plastic emissions, concentrations of plastics in the ocean surface layer (OSL) and fragmentation mechanisms is available. Here, we apply a systems engineering analytical approach and propose a tentative ‘whole ocean’ mass balance model that combines emission data, surface area-normalized plastic fragmentation rates, estimated concentrations in the OSL, and removal from the OSL by sinking. We simulate known plastic abundances in the OSL and calculate an average whole ocean apparent surface area-normalized plastic fragmentation rate constant, given representative radii for macroplastic and microplastic. Simulations show that 99.8% of the plastic that had entered the ocean since 1950 had settled below the OSL by 2016, with an additional 9.4 million tons settling per year. In 2016, the model predicts that of the 0.309 million tons in the OSL, an estimated 83.7% was macroplastic, 13.8% microplastic, and 2.5% was < 0.335 mm ‘nanoplastic’. A zero future emission simulation shows that almost all plastic in the OSL would be removed within three years, implying a fast response time of surface plastic abundance to changes in inputs. The model complements current spatially explicit models, points to future experiments that would inform critical model parameters, and allows for further validation when more experimental and field data become available.

Plastic Accumulation in the North Atlantic Subtropical Gyre

NASA Astrophysics Data System (ADS)

Law, Kara Lavender; Morét-Ferguson, Skye; Maximenko, Nikolai A.; Proskurowski, Giora; Peacock, Emily E.; Hafner, Jan; Reddy, Christopher M.

2010-09-01

Plastic marine pollution is a major environmental concern, yet a quantitative description of the scope of this problem in the open ocean is lacking. Here, we present a time series of plastic content at the surface of the western North Atlantic Ocean and Caribbean Sea from 1986 to 2008. More than 60% of 6136 surface plankton net tows collected buoyant plastic pieces, typically millimeters in size. The highest concentration of plastic debris was observed in subtropical latitudes and associated with the observed large-scale convergence in surface currents predicted by Ekman dynamics. Despite a rapid increase in plastic production and disposal during this time period, no trend in plastic concentration was observed in the region of highest accumulation.

Tribo-charging properties of waste plastic granules in process of tribo-electrostatic separation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Li, Jia, E-mail: weee@sjtu.edu.cn; Wu, Guiqing; Xu, Zhenming

Highlights: • The cyclone charging was more effective and stable than vibrating charging. • The small particle size was better changed than large ones and was more suitable recycled by TES. • The drying pretreatment is good for improving the short-term charging effect. - Abstract: Plastic products can be found everywhere in people’s daily life. With the consistent growth of plastic consumption, more and more plastic waste is generated. Considering the stable chemical and physics characteristics of plastic, regular waste management methods are not suitable for recycling economic strategy of each government, which has become a serious environmental problem. Recyclingmore » plastic waste is considered to be the best way to treat it, because it cannot only deduce the waste but also save the energy to produce new virgin plastic. Tribo-electrostatic separation is strongly recommended for plastic separation as it can preserve the original properties of plastic and has little additional pollution. In this study, plastic granules are generated by crushing plastic waste in waste electric and electronic equipment. The tribo-charging properties of plastic waste were studied by vibrating tribo-charging and cyclone tribo-charging. The triboelectric series obtained by vibrating was: (−)-PE–PS–PC–PVC–ABS–PP-(+), while the triboelectric series obtained by cyclone was (−)-PE–PS–PC–PVC–ABS–PP-(+). Further, the cyclone charging was more effective and stable than vibrating charging. The impact factors experiments showed that small particle size was better changed than large ones and were more suitable recycled by tribo-electrostatic separation. High relative humidity was identified as impede charging effect. The results of this study will help defining the operating parameters of subsequent separator.« less

Heterogeneous material distribution, an important reason for generation of strain-localized mylonite and frictional slip zones in the Hidaka metamorphic belt, Hokkaido, Japan

NASA Astrophysics Data System (ADS)

Tanaka, Hidemi; Shimada, Koji; Toyoshima, Tsuyoshi; Obara, Tomohiro; Niizato, Tadafumi

2004-12-01

Lithological heterogeneity of low P/T metamorphic rocks in southern area of Hidaka metamorphic belt (HMB) was formed through historical development of HMB while these rocks had been laid in ductile lower crust. Many strain-localized mylonite zones (<100 m in thickness) are preferentially developed within S-type tonalite and pelitic gneiss, which are characterized by a large modal amount of phyllosilicates (biotite+muscovite+chlorite) and quartz, compared to other lithofacies in HMB. Mylonitic foliations are more conspicuous with close to the center of the shear zone associated with increase in amounts of phyllosilicate minerals, indicating fluidenhanced weakening mechanisms were operated in plastic shear zones. Pseudotachylyte veins are observed exclusively in these mylonite zones, which were generated during exhumation stage of HMB. We conclude the seismic slip zones in southern HMB had been initiated in the ductile lower crust by concentration of localized plastic shear zones within the phyllosilicate- and quartz-rich lithofacies, which were heterogeneously formed by old metamorphic and magmatic events. Then these zones were further weakened by fluid-enhanced plastic deformation, and finally seismic slips occurred at the bottom of seismogenic upper crust, during exhumation of HMB.

Evidence of niche partitioning among bacteria living on plastics, organic particles and surrounding seawaters.

PubMed

Dussud, C; Meistertzheim, A L; Conan, P; Pujo-Pay, M; George, M; Fabre, P; Coudane, J; Higgs, P; Elineau, A; Pedrotti, M L; Gorsky, G; Ghiglione, J F

2018-05-01

Plastic pollution is widespread in ocean ecosystems worldwide, but it is unknown if plastic offers a unique habitat for bacteria compared to communities in the water column and attached to naturally-occurring organic particles. The large set of samples taken during the Tara-Mediterranean expedition revealed for the first time a clear niche partitioning between free-living (FL), organic particle-attached (PA) and the recently introduced plastic marine debris (PMD). Bacterial counts in PMD presented higher cell enrichment factors than generally observed for PA fraction, when compared to FL bacteria in the surrounding waters. Taxonomic diversity was also higher in the PMD communities, where higher evenness indicated a favorable environment for a very large number of species. Cyanobacteria were particularly overrepresented in PMD, together with essential functions for biofilm formation and maturation. The community distinction between the three habitats was consistent across the large-scale sampling in the Western Mediterranean basin. 'Plastic specific bacteria' recovered only on the PMD represented half of the OTUs, thus forming a distinct habitat that should be further considered for understanding microbial biodiversity in changing marine ecosystems. Copyright © 2017. Published by Elsevier Ltd.

Flotation separation of waste plastics for recycling-A review.

PubMed

Wang, Chong-qing; Wang, Hui; Fu, Jian-gang; Liu, You-nian

2015-07-01

The sharp increase of plastic wastes results in great social and environmental pressures, and recycling, as an effective way currently available to reduce the negative impacts of plastic wastes, represents one of the most dynamic areas in the plastics industry today. Froth flotation is a promising method to solve the key problem of recycling process, namely separation of plastic mixtures. This review surveys recent literature on plastics flotation, focusing on specific features compared to ores flotation, strategies, methods and principles, flotation equipments, and current challenges. In terms of separation methods, plastics flotation is divided into gamma flotation, adsorption of reagents, surface modification and physical regulation. Copyright © 2015 Elsevier Ltd. All rights reserved.

Dense-body aggregates as plastic structures supporting tension in smooth muscle cells.

PubMed

Zhang, Jie; Herrera, Ana M; Paré, Peter D; Seow, Chun Y

2010-11-01

The wall of hollow organs of vertebrates is a unique structure able to generate active tension and maintain a nearly constant passive stiffness over a large volume range. These properties are predominantly attributable to the smooth muscle cells that line the organ wall. Although smooth muscle is known to possess plasticity (i.e., the ability to adapt to large changes in cell length through structural remodeling of contractile apparatus and cytoskeleton), the detailed structural basis for the plasticity is largely unknown. Dense bodies, one of the most prominent structures in smooth muscle cells, have been regarded as the anchoring sites for actin filaments, similar to the Z-disks in striated muscle. Here, we show that the dense bodies and intermediate filaments formed cable-like structures inside airway smooth muscle cells and were able to adjust the cable length according to cell length and tension. Stretching the muscle cell bundle in the relaxed state caused the cables to straighten, indicating that these intracellular structures were connected to the extracellular matrix and could support passive tension. These plastic structures may be responsible for the ability of smooth muscle to maintain a nearly constant tensile stiffness over a large length range. The finding suggests that the structural plasticity of hollow organs may originate from the dense-body cables within the smooth muscle cells.

Early Blindness Results in Developmental Plasticity for Auditory Motion Processing within Auditory and Occipital Cortex

PubMed Central

Jiang, Fang; Stecker, G. Christopher; Boynton, Geoffrey M.; Fine, Ione

2016-01-01

Early blind subjects exhibit superior abilities for processing auditory motion, which are accompanied by enhanced BOLD responses to auditory motion within hMT+ and reduced responses within right planum temporale (rPT). Here, by comparing BOLD responses to auditory motion in hMT+ and rPT within sighted controls, early blind, late blind, and sight-recovery individuals, we were able to separately examine the effects of developmental and adult visual deprivation on cortical plasticity within these two areas. We find that both the enhanced auditory motion responses in hMT+ and the reduced functionality in rPT are driven by the absence of visual experience early in life; neither loss nor recovery of vision later in life had a discernable influence on plasticity within these areas. Cortical plasticity as a result of blindness has generally be presumed to be mediated by competition across modalities within a given cortical region. The reduced functionality within rPT as a result of early visual loss implicates an additional mechanism for cross modal plasticity as a result of early blindness—competition across different cortical areas for functional role. PMID:27458357

Nano-Ceramic Coated Plastics

NASA Technical Reports Server (NTRS)

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 (<100 C) is also a key to generating these ceramic coatings on the plastics. One possible way of processing nanoceramic coatings at low temperatures (< 90 C) is to take advantage of in-situ precipitated nanoparticles and nanostructures grown from aqueous solution. These nanostructures can be tailored to ceramic film formation and the subsequent microstructure development. In addition, the process provides environment- friendly processing because of the aqueous solution. Low-temperature processing has also shown versatility to generate various nanostructures. The growth of low-dimensional nanostructures (0-D, 1-D) provides a means of enhancing the crystallinity of the solution-prepared films that is of importance for photocatalytic performance. This technology can generate durable, fully functional 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.

Single-specialty management and reconstruction of necrotizing fasciitis of the upper extremities: clinical and economic benefits from a case series.

PubMed

Mattison, Gennaya; Leis, Amber R; Gupta, Subhas C

2014-05-01

Patients with necrotizing fasciitis are managed with multiple prompt, radical surgical debridements and critical care support. Debridement and reconstruction are often provided by different surgical teams. Anecdotally, single-specialty management seemed to be a more efficient management strategy. This study aimed to investigate and compare the outcomes of management by plastic surgery versus multiple disciplines through a retrospective economic and clinical analysis of patients with necrotizing fasciitis treated over 8 years. We also present 3 index cases for which our service functioned as the primary management team. Necrotizing fasciitis cases evaluated and treated by our department, covering both Level I and Level II Trauma Centers, were reviewed for total charges, length of hospital stay, length of intensive care unit (ICU) stay, and number of procedures. The admission Acute Physiology and Chronic Health Evaluation II score was calculated for each patient. Three comparative index cases of upper extremity necrotizing fasciitis managed primarily by the plastic surgery team are presented in greater detail. Patients managed primarily by the plastic surgery service had equivalent Acute Physiology and Chronic Health Evaluation II scores to patients managed by multiple services for their necrotizing fasciitis, with the average score higher for patients managed by plastic surgery alone. In a case-matched series of upper extremity necrotizing fasciitis, the patients admitted directly to plastic surgery had shorter average lengths of hospital and ICU stays as well as decreased total number of procedures, resulting in decreased average total hospital charges. There were no amputations among the cases treated primarily by the plastic surgery. The patients also required smaller areas of reconstruction with skin grafting despite large initial areas of debridement compared to those whose reconstructive teams differed from the team performing the debridement. Improved economic and clinical outcomes-as indicated by the reduced lengths of overall and ICU stay, the reduced number of procedures, none of the cases requiring amputation, and the reduced need for skin grafting-may be attainable when the surgeon eventually performing the reconstruction is involved early in management. We propose that, in the interest of improving patient care, a closer collaboration should be established between the reconstructive and primary managing teams.

Ablation of Cerebellar Nuclei Prevents H-Reflex Down-Conditioning in Rats

ERIC Educational Resources Information Center

Chen, Xiang Yang; Wolpaw, Jonathan R.

2005-01-01

While studies of cerebellar involvement in learning and memory have described plasticity within the cerebellum, its role in acquisition of plasticity elsewhere in the CNS is largely unexplored. This study set out to determine whether the cerebellum is needed for acquisition of the spinal cord plasticity that underlies operantly conditioned…

Erosion of a grooved surface caused by impact of particle-laden flow

NASA Astrophysics Data System (ADS)

Jung, Sohyun; Yang, Eunjin; Kim, Ho-Young

2016-11-01

Solid erosion can be a life-limiting process for mechanical elements in erosive environments, thus it is of practical importance in many industries such as construction, mining, and coal conversion. Erosion caused by particle-laden flow occurs through diverse mechanisms, such as cutting, plastic deformation, brittle fracture, fatigue and melting, depending on particle velocity, total particle mass and impingement angle. Among a variety of attempts to lessen erosion, here we investigate the effectiveness of millimeter-sized grooves on the surface. By experimentally measuring the erosion rates of smooth and triangular-grooved surfaces under various impingement angles, we find that erosion can be significantly reduced within a finite range of impingement angles. We show that such erosion resistance is attributed to the swirls of air within grooves and the differences in erosive strength of normal and slanted impact. In particular, erosion is mitigated when we increase the effective area under normal impact causing plastic deformation and fracture while decreasing the area under slanted impact that cuts the surface to a large degree. Our quantitative model for the erosion rate of grooved surfaces considering the foregoing effects agrees with the measurement results.

Effects of morphine on brain plasticity.

PubMed

Beltrán-Campos, V; Silva-Vera, M; García-Campos, M L; Díaz-Cintra, S

2015-04-01

Morphine shares with other opiates and drugs of abuse the ability to modify the plasticity of brain areas that regulate the morphology of dendrites and spines, which are the primary sites of excitatory synapses in regions of the brain involved in incentive motivation, rewards, and learning. In this review we discuss the impact of morphine use during the prenatal period of brain development and its long-term consequences in murines, and then link those consequences to similar effects occurring in human neonates and adults. Repeated exposure to morphine as treatment for pain in terminally ill patients produces long-term changes in the density of postsynaptic sites (dendrites and spines) in sensitive areas of the brain, such as the prefrontal cortex, the limbic system (hippocampus, amygdala), and caudate nuclei and nucleus accumbens. This article reviews the cellular mechanisms and receptors involved, primarily dopaminergic and glutamatergic receptors, as well as synaptic plasticity brought about by changes in dendritic spines in these areas. The actions of morphine on both developing and adult brains produce alterations in the plasticity of excitatory postsynaptic sites of the brain areas involved in limbic system functions (reward and learning). Doctors need further studies on plasticity in dendrites and spines and on signaling molecules, such as calcium, in order to improve treatments for addiction. Copyright © 2014 Sociedad Española de Neurología. Published by Elsevier Espana. All rights reserved.

Plastics processing: statistics, current practices, and evaluation.

PubMed

Cooke, F

1993-11-01

The health care industry uses a huge quantity of plastic materials each year. Much of the machinery currently used, or supplied, for plastics processing is unsuitable for use in a clean environment. In this article, the author outlines the reasons for the current situation and urges companies to re-examine their plastic-processing methods, whether performed in-house or subcontracted out. Some of the factors that should be considered when evaluating plastics-processing equipment are outlined to assist companies in remaining competitive and complying with impending EC regulations on clean room standards for manufacturing areas.

Distribution and Size Relationships of Plastic Marine Debris on Beaches in South Korea.

PubMed

Lee, Jongmyoung; Lee, Jong Su; Jang, Yong Chang; Hong, Su Yeon; Shim, Won Joon; Song, Young Kyung; Hong, Sang Hee; Jang, Mi; Han, Gi Myung; Kang, Daeseok; Hong, Sunwook

2015-10-01

The characteristics of the distribution of plastic marine debris were determined on 12 beaches in South Korea in 2013 and 2014. The abundances of large micro- (1-5 mm), meso- (5-25 mm), and macroplastics (>25 mm) were 880.4, 37.7, and 1.0 particles/m(2), respectively. Styrofoam was the most abundant debris type for large microplastics and mesoplastics (99.1 and 90.9 %, respectively). Fiber (including fabric) was the most abundant of the macroplastics (54.7 %). There were no statistical differences in the mean numbers and weights of plastic debris among three beach groups from west, south, and east coasts. No significant differences were detected between the abundances of beached plastics in high strandline and backshore for all three size groups. Spearman's rank correlation was used to determine the relationships between the three debris size classes. The abundance of large microplastics was strongly correlated with that of mesoplastics for most material types, which suggests that the contamination level of large microplastics can be estimated from that of mesoplastics. As surveying of smaller particles is more labor intensive, the surveying of mesoplastics with a 5-mm sieve is an efficient and useful way to determine "hot-spots" on beaches contaminated with large microplastics.

Plastics and microplastics in the oceans: From emerging pollutants to emerged threat.

PubMed

Avio, Carlo Giacomo; Gorbi, Stefania; Regoli, Francesco

2017-07-01

Plastic production has increased dramatically worldwide over the last 60 years and it is nowadays recognized as a serious threat to the marine environment. Plastic pollution is ubiquitous, but quantitative estimates on the global abundance and weight of floating plastics are still limited, particularly for the Southern Hemisphere and the more remote regions. Some large-scale convergence zones of plastic debris have been identified, but there is the urgency to standardize common methodologies to measure and quantify plastics in seawater and sediments. Investigations on temporal trends, geographical distribution and global cycle of plastics have management implications when defining the origin, possible drifting tracks and ecological consequences of such pollution. An elevated number of marine species is known to be affected by plastic contamination, and a more integrated ecological risk assessment of these materials has become a research priority. Beside entanglement and ingestion of macro debris by large vertebrates, microplastics are accumulated by planktonic and invertebrate organisms, being transferred along food chains. Negative consequences include loss of nutritional value of diet, physical damages, exposure to pathogens and transport of alien species. In addition, plastics contain chemical additives and efficiently adsorb several environmental contaminants, thus representing a potential source of exposure to such compounds after ingestion. Complex ecotoxicological effects are increasingly reported, but the fate and impact of microplastics in the marine environment are still far to be fully clarified. Copyright © 2016 Elsevier Ltd. All rights reserved.

Facile characterization of polymer fractions from waste electrical and electronic equipment (WEEE) for mechanical recycling.

PubMed

Taurino, Rosa; Pozzi, Paolo; Zanasi, Tania

2010-12-01

In view of the environmental problem involved in the management of WEEE, and then in the recycling of post-consumer plastic of WEEE there is a pressing need for rapid measurement technologies for simple identification of the various commercial plastic materials and of the several contaminants, to improve the recycling of such wastes. This research is focused on the characterization and recycling of two types of plastics, namely plastic from personal computer (grey plastic) and plastic from television (black plastic). Various analytical techniques were used to monitor the compositions of WEEE. Initially, the chemical structure of each plastic material was identified by Fourier transform infrared (FTIR) spectroscopy and differential scanning calorimetry (DSC). Polymeric contaminants of these plastics, in particular brominated flame retardants (BFRs) were detected in grey plastics only using different techniques. These techniques are useful for a rapid, correct and economics identification of a large volumes of WEEE plastics. Copyright © 2010 Elsevier Ltd. All rights reserved.

The Impact of a Plastic Surgeon's Gender on Patient Choice.

PubMed

Huis In 't Veld, Eva A; Canales, Francisco L; Furnas, Heather J

2017-04-01

In the patient-driven market of aesthetic surgery, an understanding of the factors that patients consider in their choice of surgeon can inform the individual plastic surgeon's marketing strategy. Previous studies have investigated patient gender preferences for physicians in other specialties, but none has investigated whether patients consider gender when choosing a plastic surgeon. The purpose of this study is to determine the impact of a plastic surgeon's gender on patient choice. A prospective study was conducted in a single private practice of two plastic surgeons, one male and one female, both closely matched in training, experience, and reputation. Two hundred consecutive patients calling for a consultation were asked if they preferred a male or female doctor; their preference, age, and area(s) of interest were recorded. All patients were women. Nearly half (46%) had no gender preference, 26% requested a female surgeon, and 1% requested a male. Preference for a female surgeon was significant (Binomial-test: P < 0.001). The remaining 27% requested a specific doctor, with slightly more requesting (53.7%) the male surgeon by name, than requested the female surgeon by name (46.3%), a difference that was not statistically significant (P = 0.683). Most female patients interested in aesthetic surgery have no gender preference. Of those who do, nearly all requested a female plastic surgeon. More important than a plastic surgeon's gender, however, is a plastic surgeon's reputation. © The Author 2016. Published by Oxford University Press on behalf of The American Society for Aesthetic Plastic Surgery.

Plastic litter in sediments from a marine area likely to become protected (Aeolian Archipelago's islands, Tyrrhenian sea).

PubMed

Fastelli, Paolo; Blašković, Andrea; Bernardi, Giulia; Romeo, Teresa; Čižmek, Hrvoje; Andaloro, Franco; Russo, Giovanni F; Guerranti, Cristiana; Renzi, Monia

2016-12-15

This research aims to define for the first time levels and patterns of different litter groups (macro, meso and microplastics) in sediments from a marine area designed for the institution of a new marine protected area (Aeolian Archipelago, Italy). Microplastics resulted the principal group and found in all samples analyzed, with shape and colours variable between different sampling sites. MPs levels measured in this study are similar to values recorded in harbour sites and lower than reported in Adriatic Sea, while macroplastics levels are notably lower than in harbor sites. Sediment grain-size and island extent resulted not significant in determining levels and distribution of plastic debris among islands. In the future, following the establishment of the MPA in the study area, these basic data will be useful to check for potential protective effects on the levels and distribution of plastic debris. Copyright © 2016 Elsevier Ltd. All rights reserved.

Environmental and health hazard ranking and assessment of plastic polymers based on chemical composition.

PubMed

Lithner, Delilah; Larsson, Ake; Dave, Göran

2011-08-15

Plastics constitute a large material group with a global annual production that has doubled in 15 years (245 million tonnes in 2008). Plastics are present everywhere in society and the environment, especially the marine environment, where large amounts of plastic waste accumulate. The knowledge of human and environmental hazards and risks from chemicals associated with the diversity of plastic products is very limited. Most chemicals used for producing plastic polymers are derived from non-renewable crude oil, and several are hazardous. These may be released during the production, use and disposal of the plastic product. In this study the environmental and health hazards of chemicals used in 55 thermoplastic and thermosetting polymers were identified and compiled. A hazard ranking model was developed for the hazard classes and categories in the EU classification and labelling (CLP) regulation which is based on the UN Globally Harmonized System. The polymers were ranked based on monomer hazard classifications, and initial assessments were made. The polymers that ranked as most hazardous are made of monomers classified as mutagenic and/or carcinogenic (category 1A or 1B). These belong to the polymer families of polyurethanes, polyacrylonitriles, polyvinyl chloride, epoxy resins, and styrenic copolymers. All have a large global annual production (1-37 million tonnes). A considerable number of polymers (31 out of 55) are made of monomers that belong to the two worst of the ranking model's five hazard levels, i.e. levels IV-V. The polymers that are made of level IV monomers and have a large global annual production (1-5 million tonnes) are phenol formaldehyde resins, unsaturated polyesters, polycarbonate, polymethyl methacrylate, and urea-formaldehyde resins. This study has identified hazardous substances used in polymer production for which the risks should be evaluated for decisions on the need for risk reduction measures, substitution, or even phase out. Copyright © 2011 Elsevier B.V. All rights reserved.

Plastic Technology (Production). Industrial Arts, Senior High--Level II. North Dakota Senior High Industrial Arts Curriculum Guides.

ERIC Educational Resources Information Center

Claus, Robert; And Others

This course guide for a plastic technology course is one of four developed for the production area in the North Dakota senior high industrial arts education program. (Eight other guides are available for two other areas of Industrial Arts--energy/power and graphic communications.) Part 1 provides such introductory information as a definition and…

Large-Scale Simulations of Plastic Neural Networks on Neuromorphic Hardware

PubMed Central

Knight, James C.; Tully, Philip J.; Kaplan, Bernhard A.; Lansner, Anders; Furber, Steve B.

2016-01-01

SpiNNaker is a digital, neuromorphic architecture designed for simulating large-scale spiking neural networks at speeds close to biological real-time. Rather than using bespoke analog or digital hardware, the basic computational unit of a SpiNNaker system is a general-purpose ARM processor, allowing it to be programmed to simulate a wide variety of neuron and synapse models. This flexibility is particularly valuable in the study of biological plasticity phenomena. A recently proposed learning rule based on the Bayesian Confidence Propagation Neural Network (BCPNN) paradigm offers a generic framework for modeling the interaction of different plasticity mechanisms using spiking neurons. However, it can be computationally expensive to simulate large networks with BCPNN learning since it requires multiple state variables for each synapse, each of which needs to be updated every simulation time-step. We discuss the trade-offs in efficiency and accuracy involved in developing an event-based BCPNN implementation for SpiNNaker based on an analytical solution to the BCPNN equations, and detail the steps taken to fit this within the limited computational and memory resources of the SpiNNaker architecture. We demonstrate this learning rule by learning temporal sequences of neural activity within a recurrent attractor network which we simulate at scales of up to 2.0 × 104 neurons and 5.1 × 107 plastic synapses: the largest plastic neural network ever to be simulated on neuromorphic hardware. We also run a comparable simulation on a Cray XC-30 supercomputer system and find that, if it is to match the run-time of our SpiNNaker simulation, the super computer system uses approximately 45× more power. This suggests that cheaper, more power efficient neuromorphic systems are becoming useful discovery tools in the study of plasticity in large-scale brain models. PMID:27092061

Use of recycled plastics in concrete: A critical review.

PubMed

Gu, Lei; Ozbakkaloglu, Togay

2016-05-01

Plastics have become an essential part of our modern lifestyle, and the global plastic production has increased immensely during the past 50years. This has contributed greatly to the production of plastic-related waste. Reuse of waste and recycled plastic materials in concrete mix as an environmental friendly construction material has drawn attention of researchers in recent times, and a large number of studies reporting the behavior of concrete containing waste and recycled plastic materials have been published. This paper summarizes the current published literature until 2015, discussing the material properties and recycling methods of plastic and the influence of plastic materials on the properties of concrete. To provide a comprehensive review, a total of 84 studies were considered, and they were classified into sub categories based on whether they dealt with concrete containing plastic aggregates or plastic fibers. Furthermore, the morphology of concrete containing plastic materials is described in this paper to explain the influence of plastic aggregates and plastic fibers on the properties of concrete. The properties of concretes containing virgin plastic materials were also reviewed to establish their similarities and differences with concrete containing recycled plastics. Copyright © 2016 Elsevier Ltd. All rights reserved.

Un algorithme efficace d'intégration plastique pour un matériau obéissant au critère anisotrope de Hill

NASA Astrophysics Data System (ADS)

Titeux, Isabelle; Li, Yuming M.; Debray, Karl; Guo, Ying-Qiao

2004-11-01

This Note deals with an efficient algorithm to carry out the plastic integration and compute the stresses due to large strains for materials satisfying the Hill's anisotropic yield criterion. The classical algorithm of plastic integration such as 'Return Mapping Method' is largely used for nonlinear analyses of structures and numerical simulations of forming processes, but it requires an iterative schema and may have convergence problems. A new direct algorithm based on a scalar method is developed which allows us to directly obtain the plastic multiplier without an iteration procedure; thus the computation time is largely reduced and the numerical problems are avoided. To cite this article: I. Titeux et al., C. R. Mecanique 332 (2004).

Knockdown of FoxP2 alters spine density in Area X of the zebra finch.

PubMed

Schulz, S B; Haesler, S; Scharff, C; Rochefort, C

2010-10-01

Mutations in the gene encoding the transcription factor FoxP2 impair human speech and language. We have previously shown that deficits in vocal learning occur in zebra finches after reduction of FoxP2 in Area X, a striatal nucleus involved in song acquisition. We recently showed that FoxP2 is expressed in newly generated spiny neurons (SN) in adult Area X as well as in the ventricular zone (VZ) from which the SN originates. Moreover, their recruitment to Area X increases transiently during the song learning phase. The present report therefore investigated whether FoxP2 is involved in the structural plasticity of Area X. We assessed the proliferation, differentiation and morphology of SN after lentivirally mediated knockdown of FoxP2 in Area X or in the VZ during the song learning phase. Proliferation rate was not significantly affected by knockdown of FoxP2 in the VZ. In addition, FoxP2 reduction both in the VZ and in Area X did not affect the number of new neurons in Area X. However, at the fine-structural level, SN in Area X bore fewer spines after FoxP2 knockdown. This effect was even more pronounced when neurons received the knockdown before differentiation, i.e. as neuroblasts in the VZ. These results suggest that FoxP2 might directly or indirectly regulate spine dynamics in Area X and thereby influence song plasticity. Together, these data present the first evidence for a role of FoxP2 in the structural plasticity of dendritic spines and complement the emerging evidence of physiological synaptic plasticity in FoxP2 mouse models. Genes, Brain and Behavior © 2010 Blackwell Publishing Ltd and International Behavioural and Neural Genetics Society. No claim to original US government works.

Legal and institutional tools to mitigate plastic pollution affecting marine species: Argentina as a case study.

PubMed

González Carman, Victoria; Machain, Natalia; Campagna, Claudio

2015-03-15

Plastics are the most common form of debris found along the Argentine coastline. The Río de la Plata estuarine area is a relevant case study to describe a situation where ample policy exists against a backdrop of plastics disposed by populated coastal areas, industries, and vessels; with resultant high impacts of plastic pollution on marine turtles and mammals. Policy and institutions are in place but the impact remains due to ineffective waste management, limited public education and awareness, and weaknesses in enforcement of regulations. This context is frequently repeated all over the world. We list possible interventions to increase the effectiveness of policy that require integrating efforts among governments, the private sector, non-governmental organizations and the inhabitants of coastal cities to reduce the amount of plastics reaching the Río de la Plata and protect threatened marine species. What has been identified for Argentina applies to the region and globally. Copyright © 2015 Elsevier Ltd. All rights reserved.

Mirrored STDP Implements Autoencoder Learning in a Network of Spiking Neurons.

PubMed

Burbank, Kendra S

2015-12-01

The autoencoder algorithm is a simple but powerful unsupervised method for training neural networks. Autoencoder networks can learn sparse distributed codes similar to those seen in cortical sensory areas such as visual area V1, but they can also be stacked to learn increasingly abstract representations. Several computational neuroscience models of sensory areas, including Olshausen & Field's Sparse Coding algorithm, can be seen as autoencoder variants, and autoencoders have seen extensive use in the machine learning community. Despite their power and versatility, autoencoders have been difficult to implement in a biologically realistic fashion. The challenges include their need to calculate differences between two neuronal activities and their requirement for learning rules which lead to identical changes at feedforward and feedback connections. Here, we study a biologically realistic network of integrate-and-fire neurons with anatomical connectivity and synaptic plasticity that closely matches that observed in cortical sensory areas. Our choice of synaptic plasticity rules is inspired by recent experimental and theoretical results suggesting that learning at feedback connections may have a different form from learning at feedforward connections, and our results depend critically on this novel choice of plasticity rules. Specifically, we propose that plasticity rules at feedforward versus feedback connections are temporally opposed versions of spike-timing dependent plasticity (STDP), leading to a symmetric combined rule we call Mirrored STDP (mSTDP). We show that with mSTDP, our network follows a learning rule that approximately minimizes an autoencoder loss function. When trained with whitened natural image patches, the learned synaptic weights resemble the receptive fields seen in V1. Our results use realistic synaptic plasticity rules to show that the powerful autoencoder learning algorithm could be within the reach of real biological networks.

Mirrored STDP Implements Autoencoder Learning in a Network of Spiking Neurons

PubMed Central

Burbank, Kendra S.

2015-01-01

The autoencoder algorithm is a simple but powerful unsupervised method for training neural networks. Autoencoder networks can learn sparse distributed codes similar to those seen in cortical sensory areas such as visual area V1, but they can also be stacked to learn increasingly abstract representations. Several computational neuroscience models of sensory areas, including Olshausen & Field’s Sparse Coding algorithm, can be seen as autoencoder variants, and autoencoders have seen extensive use in the machine learning community. Despite their power and versatility, autoencoders have been difficult to implement in a biologically realistic fashion. The challenges include their need to calculate differences between two neuronal activities and their requirement for learning rules which lead to identical changes at feedforward and feedback connections. Here, we study a biologically realistic network of integrate-and-fire neurons with anatomical connectivity and synaptic plasticity that closely matches that observed in cortical sensory areas. Our choice of synaptic plasticity rules is inspired by recent experimental and theoretical results suggesting that learning at feedback connections may have a different form from learning at feedforward connections, and our results depend critically on this novel choice of plasticity rules. Specifically, we propose that plasticity rules at feedforward versus feedback connections are temporally opposed versions of spike-timing dependent plasticity (STDP), leading to a symmetric combined rule we call Mirrored STDP (mSTDP). We show that with mSTDP, our network follows a learning rule that approximately minimizes an autoencoder loss function. When trained with whitened natural image patches, the learned synaptic weights resemble the receptive fields seen in V1. Our results use realistic synaptic plasticity rules to show that the powerful autoencoder learning algorithm could be within the reach of real biological networks. PMID:26633645

Ubiquitous and temperature-dependent neural plasticity in hibernators.

PubMed

von der Ohe, Christina G; Darian-Smith, Corinna; Garner, Craig C; Heller, H Craig

2006-10-11

Hibernating mammals are remarkable for surviving near-freezing brain temperatures and near cessation of neural activity for a week or more at a time. This extreme physiological state is associated with dendritic and synaptic changes in hippocampal neurons. Here, we investigate whether these changes are a ubiquitous phenomenon throughout the brain that is driven by temperature. We iontophoretically injected Lucifer yellow into several types of neurons in fixed slices from hibernating ground squirrels. We analyzed neuronal microstructure from animals at several stages of torpor at two different ambient temperatures, and during the summer. We show that neuronal cell bodies, dendrites, and spines from several cell types in hibernating ground squirrels retract on entry into torpor, change little over the course of several days, and then regrow during the 2 h return to euthermia. Similar structural changes take place in neurons from the hippocampus, cortex, and thalamus, suggesting a global phenomenon. Investigation of neural microstructure from groups of animals hibernating at different ambient temperatures revealed that there is a linear relationship between neural retraction and minimum body temperature. Despite significant temperature-dependent differences in extent of retraction during torpor, recovery reaches the same final values of cell body area, dendritic arbor complexity, and spine density. This study demonstrates large-scale and seemingly ubiquitous neural plasticity in the ground squirrel brain during torpor. It also defines a temperature-driven model of dramatic neural plasticity, which provides a unique opportunity to explore mechanisms of large-scale regrowth in adult mammals, and the effects of remodeling on learning and memory.

Silicon thin-film transistor backplanes on flexible substrates

NASA Astrophysics Data System (ADS)

Kattamis, Alexis Z.

Flexible large area electronics, especially for displays, is a rapidly growing field. Since hydrogenated amorphous silicon thin-film transistors (a-Si:H TFTs) have become the industry standard for liquid crystal displays, it makes sense that they be used in any transition from glass substrates to flexible substrates. The goal of this thesis work was to implement a-Si:H backplane technology on stainless steel and clear plastic substrates, with minimal recipe changes to ensure high device quality. When fabricating TFTs on flexible substrates many new issues arise, from thin-film fracture to overlay alignment errors. Our approach was to maintain elevated deposition temperatures (˜300°C) and engineer methods to minimize these problems, rather than reducing deposition temperatures. The resulting TFTs exhibit more stable operation than their low temperature counterparts and are therefore similar to the TFTs produced on glass. Two display projects using a-Si:H TFTs will be discussed in detail. They are an active-matrix organic light emitting display (AMOLED) on stainless steel and an active-matrix electrophoretic display (AMEPD) on clear plastic, with TFTs deposited at 250°C-280°C. Achieving quality a-Si:H TFTs on these substrates required addressing a host of technical challenges, including surface roughness and feature misalignment. Nanocrystalline silicon (nc-Si) was also implemented on a clear plastic substrate as a possible alternative to a-Si:H. nc-Si:H TFTs can be deposited using the same techniques as a-Si:H but yield carrier mobilities one order of magnitude greater. Their large mobilities could enable high resolution OLED displays and system-on-panel electronics.

Diffractive optics in large sizes: computer-generated holograms (CGH) based on Bayfol HX photopolymer

NASA Astrophysics Data System (ADS)

Bruder, Friedrich-Karl; Fäcke, Thomas; Hagen, Rainer; Hönel, Dennis; Kleinschmidt, Tim Patrick; Orselli, Enrico; Rewitz, Christian; Rölle, Thomas; Walze, Günther

2015-03-01

Volume Holographic Optical Elements (vHOE) offer angular and spectral Bragg selectivity that can be tuned by film thickness and holographic recording conditions. With the option to integrate complex optical function in a very thin plastic layer formerly heavy refractive optics can be made thin and lightweight especially for large area applications like liquid crystal displays, projection screens or photovoltaic. Additionally their Bragg selectivity enables the integration of several completely separated optical functions in the same film. The new instant developing photopolymer film (Bayfol® HX) paves the way towards new cost effective diffractive large optics, due to its easy holographic recording and environmental stability. A major bottleneck for large area applications has been the master hologram recording which traditionally needs expensive, large high precision optical equipment and high power laser with long coherence length. Further the recording setup needs to be rearranged for a change in optical design. In this paper we describe an alternative method for large area holographic master recording, using standard optics and low power lasers in combination with an x, y-translation stage. In this setup small sub-holograms generated by a phase only spatial light modulator (SLM) are recorded next to each other to generate a large size vHOE. The setup is flexible to generate various types of HOEs without the need of a change in the mechanical and optical construction by convenient SLM programming. One Application example and parameter studies for printed vHOEs based on Bayfol® HX Photopolymer will be given.

The pollution of the marine environment by plastic debris: a review.

PubMed

Derraik, José G B

2002-09-01

The deleterious effects of plastic debris on the marine environment were reviewed by bringing together most of the literature published so far on the topic. A large number of marine species is known to be harmed and/or killed by plastic debris, which could jeopardize their survival, especially since many are already endangered by other forms of anthropogenic activities. Marine animals are mostly affected through entanglement in and ingestion of plastic litter. Other less known threats include the use of plastic debris by "invader" species and the absorption of polychlorinated biphenyls from ingested plastics. Less conspicuous forms, such as plastic pellets and "scrubbers" are also hazardous. To address the problem of plastic debris in the oceans is a difficult task, and a variety of approaches are urgently required. Some of the ways to mitigate the problem are discussed.

Management of plastic wastes at Brazilian ports and diagnosis of their generation.

PubMed

Neffa Gobbi, Clarice; Lourenço Sanches, Vânia Maria; Acordi Vasques Pacheco, Elen Beatriz; de Oliveira Cavalcanti Guimarães, Maria José; Vasconcelos de Freitas, Marcos Aurélio

2017-11-15

This study evaluated the management of plastic wastes at 20 Brazilian maritime ports, from three sources: vessels, leased and non-leased areas. The data were obtained from documents on port wastes organized in a relational database with defined protocols (closed form). Analysis of the spreadsheets prepared and field visits revealed that the main bottleneck in managing plastic wastes at ports is their segregation. In general, more material is segregated and sent for recycling from leased areas than non-leased ones (administered by the government). This relatively better performance in managing the wastes generated in leased areas is probably due to the need for private operators to comply with the international standards such as the Code of Environmental Practice to satisfy the international market. Copyright © 2017 Elsevier Ltd. All rights reserved.

Interfacial interactions between plastic particles in plastics flotation.

PubMed

Wang, Chong-qing; Wang, Hui; Gu, Guo-hua; Fu, Jian-gang; Lin, Qing-quan; Liu, You-nian

2015-12-01

Plastics flotation used for recycling of plastic wastes receives increasing attention for its industrial application. In order to study the mechanism of plastics flotation, the interfacial interactions between plastic particles in flotation system were investigated through calculation of Lifshitz-van der Waals (LW) function, Lewis acid-base (AB) Gibbs function, and the extended Derjaguin-Landau-Verwey-Overbeek potential energy profiles. The results showed that van der Waals force between plastic particles is attraction force in flotation system. The large hydrophobic attraction, caused by the AB Gibbs function, is the dominant interparticle force. Wetting agents present significant effects on the interfacial interactions between plastic particles. It is found that adsorption of wetting agents promotes dispersion of plastic particles and decreases the floatability. Pneumatic flotation may improve the recovery and purity of separated plastics through selective adsorption of wetting agents on plastic surface. The relationships between hydrophobic attraction and surface properties were also examined. It is revealed that there exists a three-order polynomial relationship between the AB Gibbs function and Lewis base component. Our finding provides some insights into mechanism of plastics flotation. Copyright © 2015 Elsevier Ltd. All rights reserved.

Improved flight-simulator viewing lens

NASA Technical Reports Server (NTRS)

Kahlbaum, W. M.

1979-01-01

Triplet lens system uses two acrylic plastic double convex lenses and one polystyrene plastic single convex lens to reduce chromatic distortion and lateral aberation, especially at large field angles within in-line systems of flight simulators.

40 CFR 63.5805 - What standards must I meet to comply with this subpart?

Code of Federal Regulations, 2010 CFR

2010-07-01

... CATEGORIES National Emissions Standards for Hazardous Air Pollutants: Reinforced Plastic Composites... gel coat plus applied. (2)(i) If your new facility manufactures large reinforced plastic composites...

Large developing receptive fields using a distributed and locally reprogrammable address-event receiver.

PubMed

Bamford, Simeon A; Murray, Alan F; Willshaw, David J

2010-02-01

A distributed and locally reprogrammable address-event receiver has been designed, in which incoming address-events are monitored simultaneously by all synapses, allowing for arbitrarily large axonal fan-out without reducing channel capacity. Synapses can change the address of their presynaptic neuron, allowing the distributed implementation of a biologically realistic learning rule, with both synapse formation and elimination (synaptic rewiring). Probabilistic synapse formation leads to topographic map development, made possible by a cross-chip current-mode calculation of Euclidean distance. As well as synaptic plasticity in rewiring, synapses change weights using a competitive Hebbian learning rule (spike-timing-dependent plasticity). The weight plasticity allows receptive fields to be modified based on spatio-temporal correlations in the inputs, and the rewiring plasticity allows these modifications to become embedded in the network topology.

Out-coupling membrane for large-size organic light-emitting panels with high efficiency and improved uniformity

NASA Astrophysics Data System (ADS)

Ding, Lei; Wang, Lu-Wei; Zhou, Lei; Zhang, Fang-hui

2016-12-01

An out-coupling membrane embedded with a scattering film of SiO2 spheres and polyethylene terephthalate (PET) plastic was successfully developed for 150 × 150 mm2 green OLEDs. Comparing with a reference OLED panel, an approximately 1-fold enhancement in the forward emission was obtained with an out-coupling membrane adhered to the surface of the external glass substrate of the panel. Moreover, it was verified that the emission color at different viewing angles can be stabilized without apparent spectral distortion. Particularly, the uniformity of the large-area OLEDs was greatly improved. Theoretical calculation clarified that the improved performance of the lighting panels is primarily attributed to the effect of particle scattering.

Study of influence of plastic scintillators thicknesses to detect Beta particles and Gamma radiation by means of spectral analysis of {sup 90}Sr, {sup 90}Y and {sup 137}Cs sources

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cardenas, Jose Patricio Nahuel; Filho, Tufic Madi; Pereira, Maria da Conceicao Costa

2015-07-01

The Nuclear and Energy Research Institute - IPEN, offers post-graduate programs, namely: Nuclear Technology - Applications (TNA), Nuclear Technology - Materials (TNM), Nuclear Technology - Reactors (TNR). The Institute programs mission is to form expert technicians, physicists and engineers with a strong knowledge in their discipline to work in the nuclear area. The course: 'Theoretical Fundamentals and Practices of the Instrumentation used in Nuclear Data Acquisition' covers the use of laboratory nuclear instrumentation and the accomplishment of experiments to obtain nuclear parameters. One of these experimental exercises is object of this work: 'Study of influence of plastic scintillators to detectmore » Beta particles and Gamma radiation by means of spectral analysis of {sup 90}Sr, {sup 90}Y and {sup 137}Cs sources'. The use of scintillators plastic for the detection has the advantage of low cost, high mechanical strength, is not hygroscopic and can be manufactured in large volumes. This work aims to present the analysis of relative efficiency of detection of plastic scintillators of various thicknesses for beta particles and gamma radiation by the spectrum of {sup 137}Cs and {sup 90}Sr. Due to lack of resolution of the detectors plastic scintillators we worked with relative efficiency. The evaluation was done by reading deposited energy, using the software MAESTRO, for each detector thickness. For beta particles was observed an ideal thickness around 3 mm and the better photon efficiency was observed with increasing the thickness of the detector. The present experiment does not intend to establish a new technique for this subject: it solely aims student's practical exercises in nuclear properties of elements and detectors being part of the nuclear experimental course. (authors)« less

Reorganization of Motor Cortex by Vagus Nerve Stimulation Requires Cholinergic Innervation.

PubMed

Hulsey, Daniel R; Hays, Seth A; Khodaparast, Navid; Ruiz, Andrea; Das, Priyanka; Rennaker, Robert L; Kilgard, Michael P

2016-01-01

Vagus nerve stimulation (VNS) paired with forelimb training drives robust, specific reorganization of movement representations in the motor cortex. The mechanisms that underlie VNS-dependent enhancement of map plasticity are largely unknown. The cholinergic nucleus basalis (NB) is a critical substrate in cortical plasticity, and several studies suggest that VNS activates cholinergic circuitry. We examined whether the NB is required for VNS-dependent enhancement of map plasticity in the motor cortex. Rats were trained to perform a lever pressing task and then received injections of the immunotoxin 192-IgG-saporin to selectively lesion cholinergic neurons of the NB. After lesion, rats underwent five days of motor training during which VNS was paired with successful trials. At the conclusion of behavioral training, intracortical microstimulation was used to document movement representations in motor cortex. VNS paired with forelimb training resulted in a substantial increase in the representation of proximal forelimb in rats with an intact NB compared to untrained controls. NB lesions prevent this VNS-dependent increase in proximal forelimb area and result in representations similar to untrained controls. Motor performance was similar between groups, suggesting that differences in forelimb function cannot account for the difference in proximal forelimb representation. Together, these findings indicate that the NB is required for VNS-dependent enhancement of plasticity in the motor cortex and may provide insight into the mechanisms that underlie the benefits of VNS therapy. Copyright © 2016 Elsevier Inc. All rights reserved.

The contribution of Landsat 8 TIRS sensor data to the identification of plastic covered vineyards

NASA Astrophysics Data System (ADS)

Novelli, Antonio; Tarantino, Eufemia

2015-06-01

Plastic covering is a common practice in agricultural fields. From an agronomic point of view, plastic coverings offer many advantages against unfavourable growing conditions. This explains their widespread utilization with consequent positive impact on local economy. On the other hand, plasticulture raises both environmental and landscape issues. In the Apulia Region (Italy) the wide implementation of such practice generally relates to vineyard cultivation. Continuous vineyard protection has resulted in negative effects on the hydrogeological balance of soils, causing a deep modification of the traditional rural landscape and therefore affecting its quality. To guarantee both the protection of local economy as well as the preservation of local environment and landscape features, a detailed site mapping of the areas involved is necessary. Indeed, the quantification of this phenomenon is essential in the periodic updating of the existing land use database and in the development of local policies. In this study we evaluate the potential of the novel Thermal Infrared Sensor bands (TIRS) provided by the LANDSAT 8 mission in plasticulture discrimination. Using the evident anomaly retrieved in the study area on the Quality Assessment (QA) band, a fast procedure involving TIRS data was developed, proposing a new index (Plastic Surface Index- PSI) able to emphasize plasticulture. For the aim of this study, two different acquisition dates on a test area in the Apulia region (Italy) were analyzed, one in the growing season with high plastic covering density and one in the post-harvest period with low plastic cover density.

Biofouling on buoyant marine plastics: An experimental study into the effect of size on surface longevity.

PubMed

Fazey, Francesca M C; Ryan, Peter G

2016-03-01

Recent estimates suggest that roughly 100 times more plastic litter enters the sea than is found floating at the sea surface, despite the buoyancy and durability of many plastic polymers. Biofouling by marine biota is one possible mechanism responsible for this discrepancy. Microplastics (<5 mm in diameter) are more scarce than larger size classes, which makes sense because fouling is a function of surface area whereas buoyancy is a function of volume; the smaller an object, the greater its relative surface area. We tested whether plastic items with high surface area to volume ratios sank more rapidly by submerging 15 different sizes of polyethylene samples in False Bay, South Africa, for 12 weeks to determine the time required for samples to sink. All samples became sufficiently fouled to sink within the study period, but small samples lost buoyancy much faster than larger ones. There was a direct relationship between sample volume (buoyancy) and the time to attain a 50% probability of sinking, which ranged from 17 to 66 days of exposure. Our results provide the first estimates of the longevity of different sizes of plastic debris at the ocean surface. Further research is required to determine how fouling rates differ on free floating debris in different regions and in different types of marine environments. Such estimates could be used to improve model predictions of the distribution and abundance of floating plastic debris globally. Copyright © 2016 Elsevier Ltd. All rights reserved.

Promise and Limitations of Big Data Research in Plastic Surgery.

PubMed

Zhu, Victor Zhang; Tuggle, Charles Thompson; Au, Alexander Francis

2016-04-01

The use of "Big Data" in plastic surgery outcomes research has increased dramatically in the last 5 years. This article addresses some of the benefits and limitations of such research. This is a narrative review of large database studies in plastic surgery. There are several benefits to database research as compared with traditional forms of research, such as randomized controlled studies and cohort studies. These include the ease in patient recruitment, reduction in selection bias, and increased generalizability. As such, the types of outcomes research that are particularly suited for database studies include determination of geographic variations in practice, volume outcome analysis, evaluation of how sociodemographic factors affect access to health care, and trend analyses over time. The limitations of database research include data which are limited only to what was captured in the database, high power which can cause clinically insignificant differences to achieve statistical significance, and fishing which can lead to increased type I errors. The National Surgical Quality Improvement Project is an important general surgery database that may be useful for plastic surgeons because it is validated and has a large number of patients after over a decade of collecting data. The Tracking Operations and Outcomes for Plastic Surgeons Program is a newer database specific to plastic surgery. Databases are a powerful tool for plastic surgery outcomes research. It is critically important to understand their benefits and limitations when designing research projects or interpreting studies whose data have been drawn from them. For plastic surgeons, National Surgical Quality Improvement Project has a greater number of publications, but Tracking Operations and Outcomes for Plastic Surgeons Program is the most applicable database for plastic surgery research.

Defense Scrap Yard Handbook

DTIC Science & Technology

1985-06-01

34thermosetting" is an adjective position and the basic resin used. The major class- applied to plastics (such as melamine , phenoliL, es are:a. Acrylics...to heat or flame e. Melamine resins : melamine formalde- test plastic materials for identification purposes. hyde. They must therefore work closely...plastics, together with helpful information as to 1. Polystyrenes. their composition , characteristics and typical ap- m. Polyurethane resins (isocyanate

Does greater specific leaf area plasticity help plants to maintain a high performance when shaded?

PubMed

Liu, Yanjie; Dawson, Wayne; Prati, Daniel; Haeuser, Emily; Feng, Yanhao; van Kleunen, Mark

2016-12-01

It is frequently assumed that phenotypic plasticity can be very advantageous for plants, because it may increase environmental tolerance (fitness homeostasis). This should, however, only hold for plastic responses that are adaptive, i.e. increase fitness. Numerous studies have shown shade-induced increases in specific leaf area (SLA), and there is wide consensus that this plastic response optimizes light capture and thus has to be adaptive. However, it has rarely been tested whether this is really the case. In order to identify whether SLA plasticity does contribute to the maintenance of high biomass of plant species under shaded conditions, a meta-analytical approach was employed. The data set included 280 species and 467 individual studies from 32 publications and two unpublished experiments. Plants increased their SLA by 55·4 % on average when shaded, while they decreased their biomass by 59·9 %. Species with a high SLA under high-light control conditions showed a significantly greater ability to maintain biomass production under shade overall. However, in contrast to the expectation of a positive relationship between SLA plasticity and maintenance of plant biomass, the results indicated that species with greater SLA plasticity were less able to maintain biomass under shade. Although a high SLA per se contributes to biomass homeostasis, there was no evidence that plasticity in SLA contributes to this. Therefore, it is argued that some of the plastic changes that are frequently thought to be adaptive might simply reflect passive responses to the environment, or result as by-products of adaptive plastic responses in other traits. © The Author 2016. Published by Oxford University Press on behalf of the Annals of Botany Company. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

50 CFR 229.32 - Atlantic large whale take reduction plan regulations.

Code of Federal Regulations, 2012 CFR

2012-10-01

... marked with thin colored whipping line, thin colored plastic, or heat-shrink tubing, or other material... be dyed, painted, or marked with thin colored whipping line, thin colored plastic, or heat-shrink...

50 CFR 229.32 - Atlantic large whale take reduction plan regulations.

Code of Federal Regulations, 2013 CFR

2013-10-01

... marked with thin colored whipping line, thin colored plastic, or heat-shrink tubing, or other material... be dyed, painted, or marked with thin colored whipping line, thin colored plastic, or heat-shrink...

Brain damage and behavioural disorders in fish induced by plastic nanoparticles delivered through the food chain.

PubMed

Mattsson, Karin; Johnson, Elyse V; Malmendal, Anders; Linse, Sara; Hansson, Lars-Anders; Cedervall, Tommy

2017-09-13

The tremendous increases in production of plastic materials has led to an accumulation of plastic pollution worldwide. Many studies have addressed the physical effects of large-sized plastics on organisms, whereas few have focused on plastic nanoparticles, despite their distinct chemical, physical and mechanical properties. Hence our understanding of their effects on ecosystem function, behaviour and metabolism of organisms remains elusive. Here we demonstrate that plastic nanoparticles reduce survival of aquatic zooplankton and penetrate the blood-to-brain barrier in fish and cause behavioural disorders. Hence, for the first time, we uncover direct interactions between plastic nanoparticles and brain tissue, which is the likely mechanism behind the observed behavioural disorders in the top consumer. In a broader perspective, our findings demonstrate that plastic nanoparticles are transferred up through a food chain, enter the brain of the top consumer and affect its behaviour, thereby severely disrupting the function of natural ecosystems.

How Plastics Work

NASA Astrophysics Data System (ADS)

Bloomfield, Louis

2013-03-01

We encounter plastics every day, but despite their widespread use, amazing range of properties, and basic scientific underpinnings, most physicists--like most people--know relatively little about plastics. In contrast to hard crystalline and amorphous solids (e.g., metals, salts, ceramics, and glasses), we take plastics for granted, select them carelessly, and examine them more closely only on a need-to-know basis. By ignoring plastics until we need them, however, we risk not knowing what we don't know and using the wrong ones. To repurpose a familiar advertisement, ``there's a plastic for that.'' This talk will review some of the basic physics and science of plastics. It will examine the roles of temperature, order, intermolecular forces, entanglements, and linkages in plastics, and how those issues affect the properties of a given plastic. We'll stop along the way to recognize a few of the more familiar plastics, natural and synthetic, and explain some of their mechanical, chemical, and optical properties. The talk will conclude by explaining the remarkable properties of a plastic that has been largely misunderstood since its discovery 70 years ago: Silly Putty.

The Impact of a Plastic Surgeon’s Gender on Patient Choice

PubMed Central

Huis in ’t Veld, Eva A.; Canales, Francisco L.

2017-01-01

Abstract Background: In the patient-driven market of aesthetic surgery, an understanding of the factors that patients consider in their choice of surgeon can inform the individual plastic surgeon’s marketing strategy. Previous studies have investigated patient gender preferences for physicians in other specialties, but none has investigated whether patients consider gender when choosing a plastic surgeon. Objectives: The purpose of this study is to determine the impact of a plastic surgeon’s gender on patient choice. Methods: A prospective study was conducted in a single private practice of two plastic surgeons, one male and one female, both closely matched in training, experience, and reputation. Two hundred consecutive patients calling for a consultation were asked if they preferred a male or female doctor; their preference, age, and area(s) of interest were recorded. Results: All patients were women. Nearly half (46%) had no gender preference, 26% requested a female surgeon, and 1% requested a male. Preference for a female surgeon was significant (Binomial-test: P < 0.001). The remaining 27% requested a specific doctor, with slightly more requesting (53.7%) the male surgeon by name, than requested the female surgeon by name (46.3%), a difference that was not statistically significant (P = 0.683). Conclusions: Most female patients interested in aesthetic surgery have no gender preference. Of those who do, nearly all requested a female plastic surgeon. More important than a plastic surgeon’s gender, however, is a plastic surgeon’s reputation. PMID:27913412

Marine plastic debris emits a keystone infochemical for olfactory foraging seabirds

PubMed Central

Savoca, Matthew S.; Wohlfeil, Martha E.; Ebeler, Susan E.; Nevitt, Gabrielle A.

2016-01-01

Plastic debris is ingested by hundreds of species of organisms, from zooplankton to baleen whales, but how such a diversity of consumers can mistake plastic for their natural prey is largely unknown. The sensory mechanisms underlying plastic detection and consumption have rarely been examined within the context of sensory signals driving marine food web dynamics. We demonstrate experimentally that marine-seasoned microplastics produce a dimethyl sulfide (DMS) signature that is also a keystone odorant for natural trophic interactions. We further demonstrate a positive relationship between DMS responsiveness and plastic ingestion frequency using procellariiform seabirds as a model taxonomic group. Together, these results suggest that plastic debris emits the scent of a marine infochemical, creating an olfactory trap for susceptible marine wildlife. PMID:28861463

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

PubMed Central

Teichtmeister, S.; Aldakheel, F.

2016-01-01

This work outlines a novel variational-based theory for the phase-field modelling of ductile fracture in elastic–plastic solids undergoing large strains. The phase-field approach regularizes sharp crack surfaces within a pure continuum setting by a specific gradient damage modelling. It is linked to a formulation of gradient plasticity at finite strains. The framework includes two independent length scales which regularize both the plastic response as well as the crack discontinuities. This ensures that the damage zones of ductile fracture are inside of plastic zones, and guarantees on the computational side a mesh objectivity in post-critical ranges. PMID:27002069

Scalable parallel elastic-plastic finite element analysis using a quasi-Newton method with a balancing domain decomposition preconditioner

NASA Astrophysics Data System (ADS)

Yusa, Yasunori; Okada, Hiroshi; Yamada, Tomonori; Yoshimura, Shinobu

2018-04-01

A domain decomposition method for large-scale elastic-plastic problems is proposed. The proposed method is based on a quasi-Newton method in conjunction with a balancing domain decomposition preconditioner. The use of a quasi-Newton method overcomes two problems associated with the conventional domain decomposition method based on the Newton-Raphson method: (1) avoidance of a double-loop iteration algorithm, which generally has large computational complexity, and (2) consideration of the local concentration of nonlinear deformation, which is observed in elastic-plastic problems with stress concentration. Moreover, the application of a balancing domain decomposition preconditioner ensures scalability. Using the conventional and proposed domain decomposition methods, several numerical tests, including weak scaling tests, were performed. The convergence performance of the proposed method is comparable to that of the conventional method. In particular, in elastic-plastic analysis, the proposed method exhibits better convergence performance than the conventional method.

Respiratory neuroplasticity - Overview, significance and future directions.

PubMed

Fuller, David D; Mitchell, Gordon S

2017-01-01

Neuroplasticity is an important property of the neural system controlling breathing. However, our appreciation for its importance is still relatively new, and we have much to learn concerning different forms of plasticity, their underlying mechanisms, and their biological and clinical significance. In this brief review, we discuss several well-studied models of respiratory plasticity, including plasticity initiated by inactivity in the respiratory system, intermittent and sustained hypoxia, and traumatic injury to the spinal cord. Other aspects of respiratory plasticity are considered in other contributions to this special edition of Experimental Neurology on respiratory plasticity. Finally, we conclude with discussions concerning the biological and clinical significance of respiratory motor plasticity, and areas in need of future research effort. Copyright © 2016. Published by Elsevier Inc.

Modeling and Characterization of Near-Crack-Tip Plasticity from Micro- to Nano-Scales

NASA Technical Reports Server (NTRS)

Glaessgen, Edward H.; Saether, Erik; Hochhalter, Jacob; Smith, Stephen W.; Ransom, Jonathan B.; Yamakov, Vesselin; Gupta, Vipul

2010-01-01

Methodologies for understanding the plastic deformation mechanisms related to crack propagation at the nano-, meso- and micro-length scales are being developed. These efforts include the development and application of several computational methods including atomistic simulation, discrete dislocation plasticity, strain gradient plasticity and crystal plasticity; and experimental methods including electron backscattered diffraction and video image correlation. Additionally, methodologies for multi-scale modeling and characterization that can be used to bridge the relevant length scales from nanometers to millimeters are being developed. The paper focuses on the discussion of newly developed methodologies in these areas and their application to understanding damage processes in aluminum and its alloys.

Modeling and Characterization of Near-Crack-Tip Plasticity from Micro- to Nano-Scales

NASA Technical Reports Server (NTRS)

Glaessgen, Edward H.; Saether, Erik; Hochhalter, Jacob; Smith, Stephen W.; Ransom, Jonathan B.; Yamakov, Vesselin; Gupta, Vipul

2011-01-01

Methodologies for understanding the plastic deformation mechanisms related 10 crack propagation at the nano, meso- and micro-length scales are being developed. These efforts include the development and application of several computational methods including atomistic simulation, discrete dislocation plasticity, strain gradient plasticity and crystal plasticity; and experimental methods including electron backscattered diffraction and video image correlation. Additionally, methodologies for multi-scale modeling and characterization that can be used to bridge the relevant length scales from nanometers to millimeters are being developed. The paper focuses on the discussion of newly developed methodologies in these areas and their application to understanding damage processes in aluminum and its alloys.

Plastic accumulation in the Mediterranean sea.

PubMed

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.

Low-Cost and Rapid Fabrication of Metallic Nanostructures for Sensitive Biosensors Using Hot-Embossing and Dielectric-Heating Nanoimprint Methods.

PubMed

Lee, Kuang-Li; Wu, Tsung-Yeh; Hsu, Hsuan-Yeh; Yang, Sen-Yeu; Wei, Pei-Kuen

2017-07-02

We propose two approaches-hot-embossing and dielectric-heating nanoimprinting methods-for low-cost and rapid fabrication of periodic nanostructures. Each nanofabrication process for the imprinted plastic nanostructures is completed within several seconds without the use of release agents and epoxy. Low-cost, large-area, and highly sensitive aluminum nanostructures on A4 size plastic films are fabricated by evaporating aluminum film on hot-embossing nanostructures. The narrowest bandwidth of the Fano resonance is only 2.7 nm in the visible light region. The periodic aluminum nanostructure achieves a figure of merit of 150, and an intensity sensitivity of 29,345%/RIU (refractive index unit). The rapid fabrication is also achieved by using radio-frequency (RF) sensitive plastic films and a commercial RF welding machine. The dielectric-heating, using RF power, takes advantage of the rapid heating/cooling process and lower electric power consumption. The fabricated capped aluminum nanoslit array has a 5 nm Fano linewidth and 490.46 nm/RIU wavelength sensitivity. The biosensing capabilities of the metallic nanostructures are further verified by measuring antigen-antibody interactions using bovine serum albumin (BSA) and anti-BSA. These rapid and high-throughput fabrication methods can benefit low-cost, highly sensitive biosensors and other sensing applications.

Many Point Optical Velocimetry for Gas Gun Applications

NASA Astrophysics Data System (ADS)

Pena, Michael; Becker, Steven; Garza, Anselmo; Hanache, Michael; Hixson, Robert; Jennings, Richard; Matthes, Melissa; O'Toole, Brendan; Roy, Shawoon; Trabia, Mohamed

2015-06-01

With the emergence of the multiplexed photonic Doppler velocimeter (MPDV), it is now practical to record many velocity traces simultaneously on shock physics experiments. Optical measurements of plastic deformation during high velocity impact have historically been constrained to a few measurement points. We have applied a 32-channel MPDV system to gas gun experiments in order to measure plastic deformation of a steel plate. A two dimensional array of measurement points allowed for diagnostic coverage over a large surface area of the target plate. This provided experimental flexibility to accommodate platform uncertainties as well as provide for a wealth of data from a given experiment. The two dimensional array of measurement points was imaged from an MT fiber-optic connector using off-the-shelf optical components to allow for an economical and easy-to-assemble, many-fiber probe. A two-stage, light gas gun was used to launch a Lexan projectile at velocities ranging from 4 to 6 km/s at a 12.7 mm thick A36 steel plate. Plastic deformation of the back surface was measured and compared with simulations from two different models: LS-DYNA and CTH. Comparison of results indicates that the computational analysis using both codes can reasonably simulate experiments of this type.

Switched-capacitor realization of presynaptic short-term-plasticity and stop-learning synapses in 28 nm CMOS.

PubMed

Noack, Marko; Partzsch, Johannes; Mayr, Christian G; Hänzsche, Stefan; Scholze, Stefan; Höppner, Sebastian; Ellguth, Georg; Schüffny, Rene

2015-01-01

Synaptic dynamics, such as long- and short-term plasticity, play an important role in the complexity and biological realism achievable when running neural networks on a neuromorphic IC. For example, they endow the IC with an ability to adapt and learn from its environment. In order to achieve the millisecond to second time constants required for these synaptic dynamics, analog subthreshold circuits are usually employed. However, due to process variation and leakage problems, it is almost impossible to port these types of circuits to modern sub-100nm technologies. In contrast, we present a neuromorphic system in a 28 nm CMOS process that employs switched capacitor (SC) circuits to implement 128 short term plasticity presynapses as well as 8192 stop-learning synapses. The neuromorphic system consumes an area of 0.36 mm(2) and runs at a power consumption of 1.9 mW. The circuit makes use of a technique for minimizing leakage effects allowing for real-time operation with time constants up to several seconds. Since we rely on SC techniques for all calculations, the system is composed of only generic mixed-signal building blocks. These generic building blocks make the system easy to port between technologies and the large digital circuit part inherent in an SC system benefits fully from technology scaling.

Leaf photoacclimatory responses of the tropical seagrass Thalassia testudinum under mesocosm conditions: a mechanistic scaling-up study.

PubMed

Cayabyab, Napo M; Enríquez, Susana

2007-01-01

Here, the leaf photoacclimatory plasticity and efficiency of the tropical seagrass Thalassia testudinum were examined. Mesocosms were used to compare the variability induced by three light conditions, two leaf sections and the variability observed at the collection site. The study revealed an efficient photosynthetic light use at low irradiances, but limited photoacclimatory plasticity to increase maximum photosynthetic rates (P(max)) and saturation (E(k)) and compensation (E(c)) irradiances under high light irradiance. A strong, positive and linear association between the percentage of daylight hours above saturation and the relative maximum photochemical efficiency (F(V)/F(M)) reduction observed between basal and apical leaf sections was also found. The results indicate that T. testudinum leaves have a shade-adapted physiology. However, the large amount of heterotrophic biomass that this seagrass maintains may considerably increase plant respiratory demands and their minimum quantum requirements for growth (MQR). Although the MQR still needs to be quantified, it is hypothesized that the ecological success of this climax species in the oligotrophic and highly illuminated waters of the Caribbean may rely on the ability of the canopy to regulate the optimal leaf light environment and the morphological plasticity of the whole plant to enhance total leaf area and to reduce carbon respiratory losses.

Low-Cost and Rapid Fabrication of Metallic Nanostructures for Sensitive Biosensors Using Hot-Embossing and Dielectric-Heating Nanoimprint Methods

PubMed Central

Lee, Kuang-Li; Wu, Tsung-Yeh; Hsu, Hsuan-Yeh; Yang, Sen-Yeu; Wei, Pei-Kuen

2017-01-01

We propose two approaches—hot-embossing and dielectric-heating nanoimprinting methods—for low-cost and rapid fabrication of periodic nanostructures. Each nanofabrication process for the imprinted plastic nanostructures is completed within several seconds without the use of release agents and epoxy. Low-cost, large-area, and highly sensitive aluminum nanostructures on A4 size plastic films are fabricated by evaporating aluminum film on hot-embossing nanostructures. The narrowest bandwidth of the Fano resonance is only 2.7 nm in the visible light region. The periodic aluminum nanostructure achieves a figure of merit of 150, and an intensity sensitivity of 29,345%/RIU (refractive index unit). The rapid fabrication is also achieved by using radio-frequency (RF) sensitive plastic films and a commercial RF welding machine. The dielectric-heating, using RF power, takes advantage of the rapid heating/cooling process and lower electric power consumption. The fabricated capped aluminum nanoslit array has a 5 nm Fano linewidth and 490.46 nm/RIU wavelength sensitivity. The biosensing capabilities of the metallic nanostructures are further verified by measuring antigen–antibody interactions using bovine serum albumin (BSA) and anti-BSA. These rapid and high-throughput fabrication methods can benefit low-cost, highly sensitive biosensors and other sensing applications. PMID:28671600

Exceptionally high abundances of microplastics in the oligotrophic Israeli Mediterranean coastal waters.

PubMed

van der Hal, Noam; Ariel, Asaf; Angel, Dror L

2017-03-15

Seasonal sea surface microplastic distribution was recorded at 17 sites along the Israeli Mediterranean coast. Microplastics (0.3-5mm) were found in all samples, with a mean abundance of 7.68±2.38particles/m 3 or 1,518,340particles/km 2 . Some areas had higher abundances of microplastics than others, although differences were neither consistent nor statistically significant. In some cases microplastic particles were found floating in large patches. One of these patches contained an extraordinary number of plastic particles; 324particles/m 3 or 64,812,600particles/km 2 . Microplastic abundances in Israeli coastal waters are disturbingly high; mean values were 1-2 orders of magnitude higher than abundances reported in other parts of the world. Light-colored (white or transparent) fragments were by far more abundant than all other microplastic colors and types. The results of this study underline the need for action to reduce the flux of plastics to the marine environment. Copyright © 2016 Elsevier Ltd. All rights reserved.

Amphibious fish jump better on land after acclimation to a terrestrial environment.

PubMed

Brunt, Emily M; Turko, Andy J; Scott, Graham R; Wright, Patricia A

2016-10-15

Air and water differ dramatically in density and viscosity, posing different biomechanical challenges for animal locomotion. We asked how terrestrial acclimation influences locomotion in amphibious fish, specifically testing the hypothesis that terrestrial tail flip performance is improved by plastic changes in the skeletal muscle. Mangrove rivulus Kryptolebias marmoratus, which remain largely inactive out of water, were exposed to water or air for 14 days and a subgroup of air-exposed fish was also recovered in water. Tail flip jumping performance on land improved dramatically in air-acclimated fish, they had lower lactate levels compared with control fish, and these effects were mostly reversible. Muscle plasticity significantly increased oxidative muscle cross-sectional area and fibre size, as well as the number of capillaries per fibre. Our results show that reversible changes to the oxidative skeletal muscle of K. marmoratus out of water enhance terrestrial locomotory performance, even in the absence of exercise training. © 2016. Published by The Company of Biologists Ltd.

Beach litter sourcing: A trawl along the Northern Ireland coastline.

PubMed

Williams, A T; Randerson, P; Allen, C; Cooper, J A G

2017-09-15

Fourteen non-recreational coastal locations in Northern Ireland were investigated as to whether beach litter deposition was related to seasonal or site specific factors. Litter items were counted in 100m width transects and 1km strand-line surveys over a five-season period (autumn to autumn). Survey sites comprised fishing ports; estuarine areas, north (high energy) and east coast (low energy) beaches. Fishing ports accumulated the most litter. In the 100m beach surveys, plastics, string and cord, bottle caps, food items, rope, and drink containers dominated. In strand-line surveys, large plastic pieces were dominant, followed by rope, string and cord, strapping bands (absent on beach surveys), cloth, wood (mainly pallets, fish boxes) and metal items. Multivariate analyses revealed major litter category differences between the ports and all other sites, with a lesser distinction between exposed and estuarine sites. There was no simple coastline trend and no apparent effect of seasonality between samples. Copyright © 2017 Elsevier Ltd. All rights reserved.

Compact synchrotron radiation depth lithography facility

NASA Astrophysics Data System (ADS)

Knüppel, O.; Kadereit, D.; Neff, B.; Hormes, J.

1992-01-01

X-ray depth lithography allows the fabrication of plastic microstructures with heights of up to 1 mm but with the smallest possible lateral dimensions of about 1 μm. A resist is irradiated with ``white'' synchrotron radiation through a mask that is partially covered with x-ray absorbing microstructures. The plastic microstructure is then obtained by a subsequent chemical development of the irradiated resist. In order to irradiate a reasonably large resist area, the mask and the resist have to be ``scanned'' across the vertically thin beam of the synchrotron radiation. A flexible, nonexpensive and compact scanner apparatus has been built for x-ray depth lithography at the beamline BN1 at ELSA (the 3.5 GeV Electron Stretcher and Accelerator at the Physikalisches Institut of Bonn University). Measurements with an electronic water level showed that the apparatus limits the scanner-induced structure precision to not more than 0.02 μm. The whole apparatus is installed in a vacuum chamber thus allowing lithography under different process gases and pressures.

[Distribution and origin of plastic resin pellets as environmental pollutants at the East China Sea area].

PubMed

Kaminuma, T; Ohtake, C; Kabuyama, N

2000-01-01

Plastic debris are important marine pollutants. Plastic debris consist of resin pellets and waste plastics. We are particularly interested in resin pellets. We made field survey of resin pellets at nearly 400 sites in 200 beaches in Japan and neighboring countries. The pellets were found at all most all Japan coasts we surveyed and at some beaches of Macao, Hong Kong, Xiamen, the north of Taipei, and Cheju Island in Korea. The number of pellets was more than 1000 pieces per m2 on the most abundant beach in Japan. Through further analysis using GC/ECD, endocrine disrupting chemicals, PCBs, DDTs, HCHs and Nonylphenol were detected in selected samples. Biota such as Bryozoa were observed on the surface of pellets washed up on the beaches in subtropical areas. Pellets has been suspected to affect wildlife and human health, but we have no report on affection to human.

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

PubMed

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.

Ingestion of plastic marine debris by longnose lancetfish (Alepisaurus ferox) in the North Pacific Ocean.

PubMed

Jantz, Lesley A; Morishige, Carey L; Bruland, Gregory L; Lepczyk, Christopher A

2013-04-15

Plastic marine debris affects species on most trophic levels, including pelagic fish. While plastic debris ingestion has been investigated in planktivorous fish in the North Pacific Ocean, little knowledge exists on piscivorous fish. The objectives of this study were to determine the frequency of occurrence and the composition of ingested plastic marine debris in longnose lancetfish (Alepisaurus ferox), a piscivorous fish species captured in the Hawaii-based pelagic longline fishery. Nearly a quarter (47 of 192) of A. ferox sampled contained plastic marine debris, primarily in the form of plastic fragments (51.9%). No relationship existed between size (silhouette area) or amount of plastic marine debris ingested and morphometrics of A. ferox. Although A. ferox are not consumed by humans, they are common prey for fish commercially harvested for human consumption. Further research is needed to determine residence time of ingested plastic marine debris and behavior of toxins associated with plastic debris. Published by Elsevier Ltd.

Spatial and temporal variation of macro-, meso- and microplastic abundance on a remote coral island of the Maldives, Indian Ocean.

PubMed

Imhof, Hannes K; Sigl, Robert; Brauer, Emilia; Feyl, Sabine; Giesemann, Philipp; Klink, Saskia; Leupolz, Kathrin; Löder, Martin G J; Löschel, Lena A; Missun, Jan; Muszynski, Sarah; Ramsperger, Anja F R M; Schrank, Isabella; Speck, Susan; Steibl, Sebastian; Trotter, Benjamin; Winter, Isabel; Laforsch, Christian

2017-03-15

Plastic debris is ubiquitous in the marine environment and the world's shores represent a major sink. However, knowledge about plastic abundance in remote areas is scarce. Therefore, plastic abundance was investigated on a small island of the Maldives. Plastic debris (>1mm) was sampled once in natural long-term accumulation zones at the north shore and at the high tide drift line of the south shore on seven consecutive days to quantify daily plastic accumulation. Reliable identification of plastic debris was ensured by FTIR spectroscopy. Despite the remoteness of the island a considerable amount of plastic debris was present. At both sites a high variability in plastic abundance on a spatial and temporal scale was observed, which may be best explained by environmental factors. In addition, our results show that snapshot sampling may deliver biased results and indicate that future monitoring programs should consider spatial and temporal variation of plastic deposition. Copyright © 2017 Elsevier Ltd. All rights reserved.

Functional connectivity of visual cortex in the blind follows retinotopic organization principles

PubMed Central

Ovadia-Caro, Smadar; Caramazza, Alfonso; Margulies, Daniel S.; Villringer, Arno

2015-01-01

Is visual input during critical periods of development crucial for the emergence of the fundamental topographical mapping of the visual cortex? And would this structure be retained throughout life-long blindness or would it fade as a result of plastic, use-based reorganization? We used functional connectivity magnetic resonance imaging based on intrinsic blood oxygen level-dependent fluctuations to investigate whether significant traces of topographical mapping of the visual scene in the form of retinotopic organization, could be found in congenitally blind adults. A group of 11 fully and congenitally blind subjects and 18 sighted controls were studied. The blind demonstrated an intact functional connectivity network structural organization of the three main retinotopic mapping axes: eccentricity (centre-periphery), laterality (left-right), and elevation (upper-lower) throughout the retinotopic cortex extending to high-level ventral and dorsal streams, including characteristic eccentricity biases in face- and house-selective areas. Functional connectivity-based topographic organization in the visual cortex was indistinguishable from the normally sighted retinotopic functional connectivity structure as indicated by clustering analysis, and was found even in participants who did not have a typical retinal development in utero (microphthalmics). While the internal structural organization of the visual cortex was strikingly similar, the blind exhibited profound differences in functional connectivity to other (non-visual) brain regions as compared to the sighted, which were specific to portions of V1. Central V1 was more connected to language areas but peripheral V1 to spatial attention and control networks. These findings suggest that current accounts of critical periods and experience-dependent development should be revisited even for primary sensory areas, in that the connectivity basis for visual cortex large-scale topographical organization can develop without any visual experience and be retained through life-long experience-dependent plasticity. Furthermore, retinotopic divisions of labour, such as that between the visual cortex regions normally representing the fovea and periphery, also form the basis for topographically-unique plastic changes in the blind. PMID:25869851

Light-dependent leaf trait variation in 43 tropical dry forest tree species.

PubMed

Markesteijn, Lars; Poorter, Lourens; Bongers, Frans

2007-04-01

Our understanding of leaf acclimation in relation to irradiance of fully grown or juvenile trees is mainly based on research involving tropical wet forest species. We studied sun-shade plasticity of 24 leaf traits of 43 tree species in a Bolivian dry deciduous forest. Sampling was confined to small trees. For each species, leaves were taken from five of the most and five of the least illuminated crowns. Trees were selected based on the percentage of the hemisphere uncovered by other crowns. We examined leaf trait variation and the relation between trait plasticity and light demand, maximum adult stature, and ontogenetic changes in crown exposure of the species. Leaf trait variation was mainly related to differences among species and to a minor extent to differences in light availability. Traits related to the palisade layer, thickness of the outer cell wall, and N(area) and P(area) had the greatest plasticity, suggesting their importance for leaf function in different light environments. Short-lived pioneers had the highest trait plasticity. Overall plasticity was modest and rarely associated with juvenile light requirements, adult stature, or ontogenetic changes in crown exposure. Dry forest tree species had a lower light-related plasticity than wet forest species, probably because wet forests cast deeper shade. In dry forests light availability may be less limiting, and low water availability may constrain leaf trait plasticity in response to irradiance.

Potential transfer of organic pollutants from littoral plastics debris to the marine environment.

PubMed

León, Víctor M; García, Inés; González, Emilia; Samper, Raquel; Fernández-González, Verónica; Muniategui-Lorenzo, Soledad

2018-05-01

Plastic polymers act as passive samplers in air system and concentrate hydrophobic organic contaminants by sorption or specific interactions, which can be transported to other systems such as the marine environment. In this study plastic debris was sampled in the surrounding area of a Mediterranean lagoon in order to determine the concentration of persistent and emerging organic contaminants. More specifically, desorption of 91 regulated and emerging organic contaminants (polycyclic aromatic hydrocarbons, polychlorinated biphenyls, organochlorinated pesticides, current-use pesticides, personal care products, other pesticides and plastic additives) was characterized for the first 24 h from different polymers to seawater and the remaining content of these contaminants was also extracted by ultrasonic extraction with methanol. All samples were analyzed by Stir Bar Sorptive Extraction coupled to GC/MS. A significant fraction of sorbed contaminants in polymers was desorbed in the first 24 h, particularly for triazines and organophosphorus pesticides due to their lower hydrophobicity than other considered analytes. The remaining contaminants contained in plastics can be also transferred to seawater, sediments or biota. Considering 24 h desorbed fraction plus the remaining methanol extracted fraction, the highest transfer levels corresponded to personal care products, plastic additives, current-use pesticides and PAHs. This is the first study to show the relevance of the transport of organic contaminants on plastic debris from littoral areas to the marine environment. Copyright © 2018 Elsevier Ltd. All rights reserved.

Task-specific reorganization of the auditory cortex in deaf humans

PubMed Central

Bola, Łukasz; Zimmermann, Maria; Mostowski, Piotr; Jednoróg, Katarzyna; Marchewka, Artur; Rutkowski, Paweł; Szwed, Marcin

2017-01-01

The principles that guide large-scale cortical reorganization remain unclear. In the blind, several visual regions preserve their task specificity; ventral visual areas, for example, become engaged in auditory and tactile object-recognition tasks. It remains open whether task-specific reorganization is unique to the visual cortex or, alternatively, whether this kind of plasticity is a general principle applying to other cortical areas. Auditory areas can become recruited for visual and tactile input in the deaf. Although nonhuman data suggest that this reorganization might be task specific, human evidence has been lacking. Here we enrolled 15 deaf and 15 hearing adults into an functional MRI experiment during which they discriminated between temporally complex sequences of stimuli (rhythms). Both deaf and hearing subjects performed the task visually, in the central visual field. In addition, hearing subjects performed the same task in the auditory modality. We found that the visual task robustly activated the auditory cortex in deaf subjects, peaking in the posterior–lateral part of high-level auditory areas. This activation pattern was strikingly similar to the pattern found in hearing subjects performing the auditory version of the task. Although performing the visual task in deaf subjects induced an increase in functional connectivity between the auditory cortex and the dorsal visual cortex, no such effect was found in hearing subjects. We conclude that in deaf humans the high-level auditory cortex switches its input modality from sound to vision but preserves its task-specific activation pattern independent of input modality. Task-specific reorganization thus might be a general principle that guides cortical plasticity in the brain. PMID:28069964

Task-specific reorganization of the auditory cortex in deaf humans.

PubMed

Bola, Łukasz; Zimmermann, Maria; Mostowski, Piotr; Jednoróg, Katarzyna; Marchewka, Artur; Rutkowski, Paweł; Szwed, Marcin

2017-01-24

The principles that guide large-scale cortical reorganization remain unclear. In the blind, several visual regions preserve their task specificity; ventral visual areas, for example, become engaged in auditory and tactile object-recognition tasks. It remains open whether task-specific reorganization is unique to the visual cortex or, alternatively, whether this kind of plasticity is a general principle applying to other cortical areas. Auditory areas can become recruited for visual and tactile input in the deaf. Although nonhuman data suggest that this reorganization might be task specific, human evidence has been lacking. Here we enrolled 15 deaf and 15 hearing adults into an functional MRI experiment during which they discriminated between temporally complex sequences of stimuli (rhythms). Both deaf and hearing subjects performed the task visually, in the central visual field. In addition, hearing subjects performed the same task in the auditory modality. We found that the visual task robustly activated the auditory cortex in deaf subjects, peaking in the posterior-lateral part of high-level auditory areas. This activation pattern was strikingly similar to the pattern found in hearing subjects performing the auditory version of the task. Although performing the visual task in deaf subjects induced an increase in functional connectivity between the auditory cortex and the dorsal visual cortex, no such effect was found in hearing subjects. We conclude that in deaf humans the high-level auditory cortex switches its input modality from sound to vision but preserves its task-specific activation pattern independent of input modality. Task-specific reorganization thus might be a general principle that guides cortical plasticity in the brain.

Elasto-plastic impact of hemispherical shell impacting on hard rigid sphere

NASA Technical Reports Server (NTRS)

Raftopoulos, D. D.; Spicer, A. L.

1976-01-01

An analysis of plastic stress waves for cylindrical metallic projectile in impact is extended to an analysis of a hemispherical shell suffereing plastic deformation during the process of impact. It is assumed that the hemispherical shell with a prescribed launch velocity impinges a fixed rigid sphere of diameter equal to the internal diameter of the shell. The dynamic biaxial state of stress present in the shell during deformation is investigated. The analysis is valuable for studying the state of stress during large plastic deformation of a hemispherical shell.

Test and evaluation of the attic temperature reduction potential of plastic roof shakes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Holton, J.K.; Beggs, T.R.

1999-07-01

While monitoring the comparative performance of two test houses in Pittsburgh, Pennsylvania, it was noticed that the attic air temperature of one house with a plastic shake roof was consistently 20 F (11 C) cooler than its twin with asphalt shingles during peak summer cooling periods. More detailed monitoring of the temperatures on the plastic shake, the roof deck, and the attic showed this effect to be largely due to the plastic shake and not to better roof venting or other heat loss mechanisms.

Plasticity of Arabidopsis root gravitropism throughout a multidimensional condition space quantified by automated image analysis.

PubMed

Brooks, Tessa L Durham; Miller, Nathan D; Spalding, Edgar P

2010-01-01

Plant development is genetically determined but it is also plastic, a fundamental duality that can be investigated provided large number of measurements can be made in various conditions. Plasticity of gravitropism in wild-type Arabidopsis (Arabidopsis thaliana) seedling roots was investigated using automated image acquisition and analysis. A bank of computer-controlled charge-coupled device cameras acquired images with high spatiotemporal resolution. Custom image analysis algorithms extracted time course measurements of tip angle and growth rate. Twenty-two discrete conditions defined by seedling age (2, 3, or 4 d), seed size (extra small, small, medium, or large), and growth medium composition (simple or rich) formed the condition space sampled with 1,216 trials. Computational analyses including dimension reduction by principal components analysis, classification by k-means clustering, and differentiation by wavelet convolution showed distinct response patterns within the condition space, i.e. response plasticity. For example, 2-d-old roots (regardless of seed size) displayed a response time course similar to those of roots from large seeds (regardless of age). Enriching the growth medium with nutrients suppressed response plasticity along the seed size and age axes, possibly by ameliorating a mineral deficiency, although analysis of seeds did not identify any elements with low levels on a per weight basis. Characterizing relationships between growth rate and tip swing rate as a function of condition cast gravitropism in a multidimensional response space that provides new mechanistic insights as well as conceptually setting the stage for mutational analysis of plasticity in general and root gravitropism in particular.

Plasticity of Arabidopsis Root Gravitropism throughout a Multidimensional Condition Space Quantified by Automated Image Analysis1[W][OA

PubMed Central

Durham Brooks, Tessa L.; Miller, Nathan D.; Spalding, Edgar P.

2010-01-01

Plant development is genetically determined but it is also plastic, a fundamental duality that can be investigated provided large number of measurements can be made in various conditions. Plasticity of gravitropism in wild-type Arabidopsis (Arabidopsis thaliana) seedling roots was investigated using automated image acquisition and analysis. A bank of computer-controlled charge-coupled device cameras acquired images with high spatiotemporal resolution. Custom image analysis algorithms extracted time course measurements of tip angle and growth rate. Twenty-two discrete conditions defined by seedling age (2, 3, or 4 d), seed size (extra small, small, medium, or large), and growth medium composition (simple or rich) formed the condition space sampled with 1,216 trials. Computational analyses including dimension reduction by principal components analysis, classification by k-means clustering, and differentiation by wavelet convolution showed distinct response patterns within the condition space, i.e. response plasticity. For example, 2-d-old roots (regardless of seed size) displayed a response time course similar to those of roots from large seeds (regardless of age). Enriching the growth medium with nutrients suppressed response plasticity along the seed size and age axes, possibly by ameliorating a mineral deficiency, although analysis of seeds did not identify any elements with low levels on a per weight basis. Characterizing relationships between growth rate and tip swing rate as a function of condition cast gravitropism in a multidimensional response space that provides new mechanistic insights as well as conceptually setting the stage for mutational analysis of plasticity in general and root gravitropism in particular. PMID:19923240

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

NASA Astrophysics Data System (ADS)

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.

Occurrence and sources of natural and anthropogenic lipid tracers in surface soils from arid urban areas of Saudi Arabia.

PubMed

Rushdi, Ahmed I; Al-Mutlaq, Khalid F; El-Mubarak, Aarif H; Al-Saleh, Mohammed A; El-Otaibi, Mubarak T; Ibrahim, Sami M M; Simoneit, Bernd R T

2016-01-01

Soil particles contain a variety of natural and anthropogenic organic components, and in urban areas can be considered as local collectors of pollutants. Surface soil samples were taken from ten urban areas in Riyadh during early winter of 2007. They were extracted with dichloromethane-methanol mixture and the extracts were analyzed by gas chromatography-mass spectrometry. The major compounds were unresolved complex mixture (UCM), plasticizers, n-alkanes, carbohydrates, n-alkanoic acids, hopanes, n-alkanols, and sterols. Vegetation detritus was the major natural source of organic compounds (24.0 ± 15.7%) in samples from areas with less human activities and included n-alkanes, n-alkanoic acids, n-alkanols, sterols and carbohydrates. Vehicular emission products and discarded plastics were the major anthropogenic sources in the soil particles (53.3 ± 21.3% and 22.7 ± 10.7%, respectively). The anthropogenic tracers were UCM, plasticizers, n-alkanes, hopanes and traces of steranes. Vegetation and human activities control the occurrence and distribution of natural and anthropogenic extractable organic matter in this arid urban area. Copyright © 2015 Elsevier Ltd. All rights reserved.

Self-Organized Near-Zero-Lag Synchronization Induced by Spike-Timing Dependent Plasticity in Cortical Populations

PubMed Central

Matias, Fernanda S.; Carelli, Pedro V.; Mirasso, Claudio R.; Copelli, Mauro

2015-01-01

Several cognitive tasks related to learning and memory exhibit synchronization of macroscopic cortical areas together with synaptic plasticity at neuronal level. Therefore, there is a growing effort among computational neuroscientists to understand the underlying mechanisms relating synchrony and plasticity in the brain. Here we numerically study the interplay between spike-timing dependent plasticity (STDP) and anticipated synchronization (AS). AS emerges when a dominant flux of information from one area to another is accompanied by a negative time lag (or phase). This means that the receiver region pulses before the sender does. In this paper we study the interplay between different synchronization regimes and STDP at the level of three-neuron microcircuits as well as cortical populations. We show that STDP can promote auto-organized zero-lag synchronization in unidirectionally coupled neuronal populations. We also find synchronization regimes with negative phase difference (AS) that are stable against plasticity. Finally, we show that the interplay between negative phase difference and STDP provides limited synaptic weight distribution without the need of imposing artificial boundaries. PMID:26474165

Plastic changes following imitation-based speech and language therapy for aphasia: a high-density sleep EEG study.

PubMed

Sarasso, Simone; Määttä, Sara; Ferrarelli, Fabio; Poryazova, Rositsa; Tononi, Giulio; Small, Steven L

2014-02-01

BACKGROUND OBJECTIVE: measurement of plastic brain changes induced by a novel rehabilitative approach is a key requirement for validating its biological rationale linking the potential therapeutic gains to the changes in brain physiology. Based on an emerging notion linking cortical plastic changes to EEG sleep slow-wave activity (SWA) regulation, we aimed to assess the acute plastic changes induced by an imitation-based speech therapy in individuals with aphasia by comparing sleep SWA changes before and after therapy. A total of 13 left-hemispheric stroke patients underwent language assessment with the Western Aphasia Battery (WAB) before and after 2 consecutive high-density (hd) EEG sleep recordings interleaved by a daytime session of imitation-based speech therapy (Intensive Mouth Imitation and Talking for Aphasia Therapeutic Effects [IMITATE]). This protocol is thought to stimulate bilateral connections between the inferior parietal lobule and the ventral premotor areas. A single exposure to IMITATE resulted in increases in local EEG SWA during subsequent sleep over the same regions predicted by the therapeutic rationale, particularly over the right hemisphere (unaffected by the lesion). Furthermore, changes in SWA over the left-precentral areas predicted changes in WAB repetition scores in our group, supporting the role of perilesional areas in predicting positive functional responses. Our results suggest that SWA changes occurring in brain areas activated during imitation-based aphasia therapy may reflect the acute plastic changes induced by this intervention. Further testing will be needed to evaluate SWA as a non-invasive assessment of changes induced by the therapy and as a predictor of positive long-term clinical outcome.

Clioquinol and vitamin B12 (cobalamin) synergistically rescue the lead-induced impairments of synaptic plasticity in hippocampal dentate gyrus area of the anesthetized rats in vivo.

PubMed

Chen, W-H; Wang, M; Yu, S-S; Su, L; Zhu, D-M; She, J-Q; Cao, X-J; Ruan, D-Y

2007-07-13

Lead (Pb(2+)) exposure in development induces impairments of synaptic plasticity in the hippocampal dentate gyrus (DG) area of the anesthetized rats in vivo. The common chelating agents have many adverse effects and are incapable of alleviating lead-induced neurotoxicity. Recently, CQ, clioquinol (5-chloro-7-iodo-8-hydroxy-quinoline), which is a transition metal ion chelator and/or ionophore with low affinity for metal ions, has yielded some promising results in animal models and clinical trials related to dysfunctions of metal ions. In addition, CQ-associated side effects are believed to be overcome with vitamin B12 (VB12) supplementation. To determine whether CQ treatment could rescue impairments of synaptic plasticity induced by chronic Pb(2+) exposure, we investigated the input/output functions (I/Os), paired-pulse reactions (PPRs) and long-term potentiation (LTP) of different treatment groups in hippocampal DG area of the anesthetized rat in vivo by recording field potentials and measured hippocampal Pb(2+) concentrations of different treatment groups by PlasmaQuad 3 inductive coupled plasma mass spectroscopy. The results show: CQ alone does not rescue the lead-induced impairments of synaptic plasticity in hippocampal DG area of the anesthetized rats in vivo; VB12 alone partly rescues the lead-induced impairments of LTP; however the co-administration of CQ and VB12 totally rescues these impairments of synaptic plasticity and moreover, the effects of CQ and VB12 co-administration are specific to the lead-exposed animals.

New Soft Rock Pillar Strength Formula Derived Through Parametric FEA Using a Critical State Plasticity Model

NASA Astrophysics Data System (ADS)

Rastiello, Giuseppe; Federico, Francesco; Screpanti, Silvio

2015-09-01

Many abandoned room and pillar mines have been excavated not far from the surface of large areas of important European cities. In Rome, these excavations took place at shallow depths (3-15 m below the ground surface) in weak pyroclastic soft rocks. Many of these cavities have collapsed; others appear to be in a stable condition, although an appreciable percentage of their structural components (pillars, roofs, etc.) have shown increasing signs of distress from both the morphological and mechanical points of view. In this study, the stress-strain behaviour of soft rock pillars sustaining systems of cavities under vertical loads was numerically simulated, starting from the in situ initial conditions due to excavation of the cavities. The mechanical behaviour of the constituent material of the pillar was modelled according to the Modified Cam-Clay constitutive law (elasto-plastic with strain hardening). The influence of the pillar geometry (cross-section area, shape, and height) and mechanical parameters of the soft rock on the ultimate compressive strength of the pillar as a whole was parametrically investigated first. Based on the numerical results, an original relationship for pillar strength assessment was developed. Finally, the estimated pillar strengths according to the proposed formula and well-known formulations in the literature were compared.

Map showing areas with potential for talc deposits in the Gravelly, Greenhorn, and Ruby ranges and the Henrys Lake Mountains of southwestern Montana

USGS Publications Warehouse

Van Gosen, Bradley S.; Berg, Richard B.; Hammarstrom, Jane M.

1998-01-01

For the last several years, Montana has been the leading talc producing state in the United States (U.S. Geological Survey, 1996). For example, in 1992 Montana supplied about 40 percent of the U.S. mine production of talc (Virta, 1992). All of this production has come from the large deposits of high purity talc in the southwestern part of the state. All Montana talc is currently (1997) extracted from four mines, each within the study area of this map—the open pit operations of the Treasure State, Regal, and Yellowstone mines and the underground operation of the Beaverhead mine (see map numbers 1-4 on list and map to the left). The related mineral chlorite is mined at the Antler mine, located nearby, but outside of the study area in the Highland Mountains. Montana talc has at least two market advantages: (1) some deposits are very large and near surface, allowing economic mining by open pit methods; and (2) the deposits are of high purity and lack tremolite or other amphibole mineral contaminants (such as absestos) that occur in some other talc-rich deposits. Talc from southwest Montana is used in ceramics, paint, paper, plastics, cosmetics, rubber, roofing, flooring, caulking, and agricultural applications. The talc is also used in the processes of recycling paper and plastics. Talc was first discovered in the early 1900's at the present site of the Yellowstone mine (Perry, 1948, p. 9). Modest production began in 1942 from shallow pits and adits, supplying steatite (massive, compact, high-purity) talc that was used to make ceramic insulators. The southwest Montana talc industry grew to become a significant part of the region's economy; this history is described by Perry (1948), Olson (1976), and Berg (1997). Exploration and development are likely to continue for the foreseeable future for several reasons: (1) mines are active in the area at present and an infrastructure for talc processing exists; (2) large changes in domestic and export talc markets are not expected in the next few years based on recent market trends (Virta, 1997); (3) the talc of this region is especially pure and asbestos-free; and (4) except for potential ground stabilization problems and land disturbance associated with largescale open pit mining, no significant environmental impacts are associated with talc mining

Modeling water flow and nitrate dynamics in a plastic mulch vegetable cultivation system using HYDRUS-2D

NASA Astrophysics Data System (ADS)

Filipović, Vilim; Romić, Davor; Romić, Marija; Matijević, Lana; Mallmann, Fábio J. K.; Robinson, David A.

2016-04-01

Growing vegetables commercially requires intensive management and involves high irrigation demands and input of agrochemicals. Plastic mulch application in combination with drip irrigation is a common agricultural management technique practiced due to variety of benefits to the crop, mostly vegetable biomass production. However, the use of these techniques can result in various impacts on water and nutrient distribution in underlying soil and consequently affect nutrient leaching towards groundwater resources. The aim of this work is to estimate the effect of plastic mulch cover in combination with drip irrigation on water and nitrate dynamics in soil using HYDRUS-2D model. The field site was located in Croatian costal karst area on a Gleysol (WRB). The experiment was designed according to the split-plot design in three repetitions and was divided into plots with plastic mulch cover (MULCH) and control plots with bare soil (CONT). Each of these plots received applications of three levels of nitrogen fertilizer: 70, 140, and 210 kg per ha. All plots were equipped with drip irrigation and cropped with bell pepper (Capsicum annuum L. cv. Bianca F1). Lysimeters were installed at 90 cm depth in all plots and were used for monitoring the water and nitrate outflow. HYDRUS-2D was used for modeling the water and nitrogen outflow in the MULCH and CONT plots, implementing the proper boundary conditions. HYDRUS-2D simulated results showed good fitting to the field site observed data in both cumulative water and nitrate outflow, with high level of agreement. Water flow simulations produced model efficiency of 0.84 for CONT and 0.56 for MULCH plots, while nitrate simulations showed model efficiency ranging from 0.67 to 0.83 and from 0.70 to 0.93, respectively. Additional simulations were performed with the absence of the lysimeter, revealing faster transport of nitrates below drip line in the CONT plots, mostly because of the increased surface area subjected to precipitation/irrigation due the absence of soil cover. Contrary, in the MULCH plots most of the nitrate applied was still left in the upper soil layer at the end of simulations. Numerical modeling revealed a large influence of plastic mulch cover on water and nutrient outflow and distribution in soil. Results suggest that under this management practice the nitrogen amounts applied via fertigation can be lowered and optimized (higher application frequencies) to reduce possible negative influence of the nitrogen based fertilizer such as leaching of nitrates to groundwater. Keywords: Plastic mulch cover; Vegetable cultivation; Water flow; Nitrate dynamics; HYDRUS-2D

Adapting to a Changing Environment: Modeling the Interaction of Directional Selection and Plasticity.

PubMed

Nunney, Leonard

2016-01-01

Human-induced habitat loss and fragmentation constrains the range of many species, making them unable to respond to climate change by moving. For such species to avoid extinction, they must respond with some combination of phenotypic plasticity and genetic adaptation. Haldane's "cost of natural selection" limits the rate of adaptation, but, although modeling has shown that in very large populations long-term adaptation can be maintained at rates substantially faster than Haldane's suggested limit, maintaining large populations is often an impossibility, so phenotypic plasticity may be crucial in enhancing the long-term survival of small populations. The potential importance of plasticity is in "buying time" for populations subject to directional environmental change: if genotypes can encompass a greater environmental range, then populations can maintain high fitness for a longer period of time. Alternatively, plasticity could be detrimental by lessening the effectiveness of natural selection in promoting genetic adaptation. Here, I modeled a directionally changing environment in which a genotype's adaptive phenotypic plasticity is centered around the environment where its fitness is highest. Plasticity broadens environmental tolerance and, provided it is not too costly, is favored by natural selection. However, a paradoxical result of the individually advantageous spread of plasticity is that, unless the adaptive trait is determined by very few loci, the long-term extinction risk of a population increases. This effect reflects a conflict between the short-term individual benefit of plasticity and a long-term detriment to population persistence, adding to the multiple threats facing small populations under conditions of climate change. © The American Genetic Association. 2015. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

A framework for plasticity implementation on the SpiNNaker neural architecture.

PubMed

Galluppi, Francesco; Lagorce, Xavier; Stromatias, Evangelos; Pfeiffer, Michael; Plana, Luis A; Furber, Steve B; Benosman, Ryad B

2014-01-01

Many of the precise biological mechanisms of synaptic plasticity remain elusive, but simulations of neural networks have greatly enhanced our understanding of how specific global functions arise from the massively parallel computation of neurons and local Hebbian or spike-timing dependent plasticity rules. For simulating large portions of neural tissue, this has created an increasingly strong need for large scale simulations of plastic neural networks on special purpose hardware platforms, because synaptic transmissions and updates are badly matched to computing style supported by current architectures. Because of the great diversity of biological plasticity phenomena and the corresponding diversity of models, there is a great need for testing various hypotheses about plasticity before committing to one hardware implementation. Here we present a novel framework for investigating different plasticity approaches on the SpiNNaker distributed digital neural simulation platform. The key innovation of the proposed architecture is to exploit the reconfigurability of the ARM processors inside SpiNNaker, dedicating a subset of them exclusively to process synaptic plasticity updates, while the rest perform the usual neural and synaptic simulations. We demonstrate the flexibility of the proposed approach by showing the implementation of a variety of spike- and rate-based learning rules, including standard Spike-Timing dependent plasticity (STDP), voltage-dependent STDP, and the rate-based BCM rule. We analyze their performance and validate them by running classical learning experiments in real time on a 4-chip SpiNNaker board. The result is an efficient, modular, flexible and scalable framework, which provides a valuable tool for the fast and easy exploration of learning models of very different kinds on the parallel and reconfigurable SpiNNaker system.

A framework for plasticity implementation on the SpiNNaker neural architecture

PubMed Central

Galluppi, Francesco; Lagorce, Xavier; Stromatias, Evangelos; Pfeiffer, Michael; Plana, Luis A.; Furber, Steve B.; Benosman, Ryad B.

2015-01-01

Many of the precise biological mechanisms of synaptic plasticity remain elusive, but simulations of neural networks have greatly enhanced our understanding of how specific global functions arise from the massively parallel computation of neurons and local Hebbian or spike-timing dependent plasticity rules. For simulating large portions of neural tissue, this has created an increasingly strong need for large scale simulations of plastic neural networks on special purpose hardware platforms, because synaptic transmissions and updates are badly matched to computing style supported by current architectures. Because of the great diversity of biological plasticity phenomena and the corresponding diversity of models, there is a great need for testing various hypotheses about plasticity before committing to one hardware implementation. Here we present a novel framework for investigating different plasticity approaches on the SpiNNaker distributed digital neural simulation platform. The key innovation of the proposed architecture is to exploit the reconfigurability of the ARM processors inside SpiNNaker, dedicating a subset of them exclusively to process synaptic plasticity updates, while the rest perform the usual neural and synaptic simulations. We demonstrate the flexibility of the proposed approach by showing the implementation of a variety of spike- and rate-based learning rules, including standard Spike-Timing dependent plasticity (STDP), voltage-dependent STDP, and the rate-based BCM rule. We analyze their performance and validate them by running classical learning experiments in real time on a 4-chip SpiNNaker board. The result is an efficient, modular, flexible and scalable framework, which provides a valuable tool for the fast and easy exploration of learning models of very different kinds on the parallel and reconfigurable SpiNNaker system. PMID:25653580

Oil sorbents from plastic wastes and polymers: A review.

PubMed

Saleem, Junaid; Adil Riaz, Muhammad; Gordon, McKay

2018-01-05

A large volume of the waste produced across the world is composed of polymers from plastic wastes such as polyethylene (HDPE or LDPE), polypropylene (PP), and polyethylene terephthalate (PET) amongst others. For years, environmentalists have been looking for various ways to overcome the problems of such large quantities of plastic wastes being disposed of into landfill sites. On the other hand, the usage of synthetic polymers as oil sorbents in particular, polyolefins, including polypropylene (PP) and polyethylene (PE) have been reported. In recent years, the idea of using plastic wastes as the feed for the production of oil sorbents has gained momentum. However, the studies undertaking such feasibility are rather scattered. This review paper is the first of its kind reporting, compiling and reviewing these various processes. The production of an oil sorbent from plastic wastes is being seen to be satisfactorily achievable through a variety of methods Nevertheless, much work needs to be done regarding further investigation of the numerous parameters influencing production yields and sorbent qualities. For example, differences in results are seen due to varying operating conditions, experimental setups, and virgin or waste plastics being used as feeds. The field of producing oil sorbents from plastic wastes is still very open for further research, and seems to be a promising route for both waste reduction, and the synthesis of value-added products such as oil sorbents. In this review, the research related to the production of various oil sorbents based on plastics (plastic waste and virgin polymer) has been discussed. Further oil sorbent efficiency in terms of oil sorption capacity has been described. Copyright © 2017 Elsevier B.V. All rights reserved.

Contamination and risk of heavy metals in soils and sediments from a typical plastic waste recycling area in North China.

PubMed

Tang, Zhenwu; Zhang, Lianzhen; Huang, Qifei; Yang, Yufei; Nie, Zhiqiang; Cheng, Jiali; Yang, Jun; Wang, Yuwen; Chai, Miao

2015-12-01

Plastic wastes are increasingly being recycled in many countries. However, available information on the metals released into the environment during recycling processes is rare. In this study, the contamination features and risks of eight heavy metals in soils and sediments were investigated in Wen'an, a typical plastic recycling area in North China. The surface soils and sediments have suffered from moderate to high metal pollution and in particular, high Cd and Hg pollution. The mean concentrations of Cd and Hg were 0.355 and 0.408 mg kg(-1), respectively, in the soils and 1.53 and 2.10 mg kg(-1), respectively, in the sediments. The findings suggested that there is considerable to high potential ecological risks in more than half of the soils and high potential ecological risk in almost all sediments. Although the health risk levels from exposure to soil metals were acceptable for adults, the non-carcinogenic risks to local children exceeded the acceptable level. Source assessment indicated that heavy metals in soils and sediments were mainly derived from inputs from poorly controlled plastic waste recycling operations in this area. The results suggested that the risks associated with heavy metal pollution from plastic waste recycling should be of great concern. Copyright © 2015 Elsevier Inc. All rights reserved.

Proton beam shaped by “particle lens” formed by laser-driven hot electrons

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhai, S. H.; Shen, B. F., E-mail: bfshen@mail.shcnc.ac.cn, E-mail: wwpvin@hotmail.com, E-mail: yqgu@caep.cn; Wang, W. P., E-mail: bfshen@mail.shcnc.ac.cn, E-mail: wwpvin@hotmail.com, E-mail: yqgu@caep.cn

2016-05-23

Two-dimensional tailoring of a proton beam is realized by a “particle lens” in our experiment. A large quantity of electrons, generated by an intense femtosecond laser irradiating a polymer target, produces an electric field strong enough to change the trajectory and distribution of energetic protons flying through the electron area. The experiment shows that a strip pattern of the proton beam appears when hot electrons initially converge inside the plastic plate. Then the shape of the proton beam changes to a “fountain-like” pattern when these hot electrons diffuse after propagating a distance.

Atmospheric Pressure Plasma Jet as a Dry Alternative to Inkjet Printing in Flexible Electronics

NASA Technical Reports Server (NTRS)

Gandhiraman, Ram Prasad; Lopez, Arlene; Koehne, Jessica; Meyyappan, M.

2016-01-01

We have developed an atmospheric pressure plasma jet printing system that works at room temperature to 50 deg C unlike conventional aerosol assisted techniques which require a high temperature sintering step to obtain desired thin films. Multiple jets can be configured to increase throughput or to deposit multiple materials, and the jet(s) can be moved across large areas using a x-y stage. The plasma jet has been used to deposit carbon nanotubes, graphene, silver nanowires, copper nanoparticles and other materials on substrates such as paper, cotton, plastic and thin metal foils.

[Possibilities in the surgical management of eyelid trauma].

PubMed

Lipke, K J

2011-08-01

The face plays a central role in interpersonal communication and aesthetic perception. Moreover, due to the heavy dependence of ocular function on lid anatomy, the treatment of periocular injuries, particularly those involving soft tissue loss, requires profound knowledge of both anatomy and reconstructive plastic surgery. Numerous surgical procedures are described in the literature. The aim of these procedures is to achieve an optimal functional and aesthetic result according to injury localization and extent. Against this background, treating eyelid injuries presents certain challenges. Close collaboration between all areas of head surgery is required particularly in the case of large defects.

Application of dynamic milling in stainless steel processing

NASA Astrophysics Data System (ADS)

Shan, Wenju

2017-09-01

This paper mainly introduces the method of parameter setting for NC programming of stainless steel parts by dynamic milling. Stainless steel is of high plasticity and toughness, serious hard working, large cutting force, high temperature in cutting area and easy wear of tool. It is difficult to process material. Dynamic motion technology is the newest NC programming technology of Mastercam software. It is an advanced machining idea. The tool path generated by the dynamic motion technology is more smooth, more efficient and more stable in the machining process. Dynamic motion technology is very suitable for cutting hard machining materials.

High-mobility low-temperature ZnO transistors with low-voltage operation

NASA Astrophysics Data System (ADS)

Bong, Hyojin; Lee, Wi Hyoung; Lee, Dong Yun; Kim, Beom Joon; Cho, Jeong Ho; Cho, Kilwon

2010-05-01

Low voltage high mobility n-type thin film transistors (TFTs) based on sol-gel processed zinc oxide (ZnO) were fabricated using a high capacitance ion gel gate dielectric. The ion gel gated solution-processed ZnO TFTs were found to exhibit excellent electrical properties. TFT carrier mobilities were 13 cm2/V s, ON/OFF current ratios were 105, regardless of the sintering temperature used for the preparation of the ZnO thin films. Ion gel gated ZnO TFTs are successfully demonstrated on plastic substrates for the large area flexible electronics.

Time Lapse of World’s Largest 3-D Printed Object

DOE Office of Scientific and Technical Information (OSTI.GOV)

None

2016-08-29

Researchers at the MDF have 3D-printed a large-scale trim tool for a Boeing 777X, the world’s largest twin-engine jet airliner. The additively manufactured tool was printed on the Big Area Additive Manufacturing, or BAAM machine over a 30-hour period. The team used a thermoplastic pellet comprised of 80% ABS plastic and 20% carbon fiber from local material supplier. The tool has proven to decrease time, labor, cost and errors associated with traditional manufacturing techniques and increased energy savings in preliminary testing and will undergo further, long term testing.

Modeling transmission parameters of polymer microstructured fibers for applications in FTTH networks

NASA Astrophysics Data System (ADS)

Gdula, P.; Welikow, K.; Szczepański, P.; Buczyński, R.; Piramidowicz, R.

2011-10-01

This paper is focused on selected aspects of designing and modeling of transmission parameters of plastic optical fibers (POFs), considered in the context of their potential applications in optical access networks and, specifically, in Fiber-To- The-Home (FTTH) systems. The survey of state-of-the-art solutions is presented and possibility of improving transmission properties of POFs by microstructurization is discussed on the basis of the first results of numerical modeling. In particular, the microstructured POF was designed supporting propagation of limited number of modes while keeping relatively large mode area and, simultaneously, significantly lowered bending losses.

Infrared Time Lapse of World’s Largest 3D-Printed Object

DOE Office of Scientific and Technical Information (OSTI.GOV)

None

Researchers at Oak Ridge National Laboratory have 3D-printed a large-scale trim tool for a Boeing 777X, the world’s largest twin-engine jet airliner. The additively manufactured tool was printed on the Big Area Additive Manufacturing, or BAAM machine over a 30-hour period. The team used a thermoplastic pellet comprised of 80% ABS plastic and 20% carbon fiber from local material supplier. The tool has proven to decrease time, labor, cost and errors associated with traditional manufacturing techniques and increased energy savings in preliminary testing and will undergo further, long term testing.

Bipolar Nickel-Metal Hydride Battery Development Project

NASA Technical Reports Server (NTRS)

Cole, John H.

1999-01-01

This paper reviews the development of the Electro Energy, Inc.'s bipolar nickel metal hydride battery. The advantages of the design are that each cell is individually sealed, and that there are no external cell terminals, no electrode current collectors, it is compatible with plastic bonded electrodes, adaptable to heat transfer fins, scalable to large area, capacity and high voltage. The design will allow for automated flexible manufacturing, improved energy and power density and lower cost. The development and testing of the battery's component are described. Graphic presentation of the results of many of the tests are included.

Heat Pipes

NASA Technical Reports Server (NTRS)

1996-01-01

Heat Pipes were originally developed by NASA and the Los Alamos Scientific Laboratory during the 1960s to dissipate excessive heat build- up in critical areas of spacecraft and maintain even temperatures of satellites. Heat pipes are tubular devices where a working fluid alternately evaporates and condenses, transferring heat from one region of the tube to another. KONA Corporation refined and applied the same technology to solve complex heating requirements of hot runner systems in injection molds. KONA Hot Runner Systems are used throughout the plastics industry for products ranging in size from tiny medical devices to large single cavity automobile bumpers and instrument panels.

Conspecific Plasticity and Invasion: Invasive Populations of Chinese Tallow (Triadica sebifera) Have Performance Advantage over Native Populations Only in Low Soil Salinity

PubMed Central

Chen, Leiyi; Tiu, Candice J.; Peng, Shaolin; Siemann, Evan

2013-01-01

Global climate change may increase biological invasions in part because invasive species may have greater phenotypic plasticity than native species. This may be especially important for abiotic stresses such as salt inundation related to increased hurricane activity or sea level rise. If invasive species indeed have greater plasticity, this may reflect genetic differences between populations in the native and introduced ranges. Here, we examined plasticity of functional and fitness-related traits of Chinese tallow (Triadica sebifera) populations from the introduced and native ranges that were grown along a gradient of soil salinity (control: 0 ppt; Low: 5 ppt; Medium: 10 ppt; High: 15 ppt) in a greenhouse. We used both norm reaction and plasticity index (PIv) to estimate the conspecific phenotypic plasticity variation between invasive and native populations. Overall, invasive populations had higher phenotypic plasticity of height growth rate (HGR), aboveground biomass, stem biomass and specific leaf area (SLA). The plasticity Index (PIv) of height growth rate (HGR) and SLA each were higher for plants from invasive populations. Absolute performance was always comparable or greater for plants from invasive populations versus native populations with the greatest differences at low stress levels. Our results were consistent with the “Master-of-some” pattern for invasive plants in which the fitness of introduced populations was greater in more benign conditions. This suggests that the greater conspecific phenotypic plasticity of invasive populations compared to native populations may increase invasion success in benign conditions but would not provide a potential interspecific competitive advantage in higher salinity soils that may occur with global climate change in coastal areas. PMID:24040366

Conspecific plasticity and invasion: invasive populations of Chinese tallow (Triadica sebifera) have performance advantage over native populations only in low soil salinity.

PubMed

Chen, Leiyi; Tiu, Candice J; Peng, Shaolin; Siemann, Evan

2013-01-01

Global climate change may increase biological invasions in part because invasive species may have greater phenotypic plasticity than native species. This may be especially important for abiotic stresses such as salt inundation related to increased hurricane activity or sea level rise. If invasive species indeed have greater plasticity, this may reflect genetic differences between populations in the native and introduced ranges. Here, we examined plasticity of functional and fitness-related traits of Chinese tallow (Triadica sebifera) populations from the introduced and native ranges that were grown along a gradient of soil salinity (control: 0 ppt; Low: 5 ppt; Medium: 10 ppt; High: 15 ppt) in a greenhouse. We used both norm reaction and plasticity index (PIv) to estimate the conspecific phenotypic plasticity variation between invasive and native populations. Overall, invasive populations had higher phenotypic plasticity of height growth rate (HGR), aboveground biomass, stem biomass and specific leaf area (SLA). The plasticity Index (PIv) of height growth rate (HGR) and SLA each were higher for plants from invasive populations. Absolute performance was always comparable or greater for plants from invasive populations versus native populations with the greatest differences at low stress levels. Our results were consistent with the "Master-of-some" pattern for invasive plants in which the fitness of introduced populations was greater in more benign conditions. This suggests that the greater conspecific phenotypic plasticity of invasive populations compared to native populations may increase invasion success in benign conditions but would not provide a potential interspecific competitive advantage in higher salinity soils that may occur with global climate change in coastal areas.

Life-history trait plasticity and its relationships with plant adaptation and insect fitness: a case study on the aphid Sitobion avenae.

PubMed

Dai, Peng; Shi, Xiaoqin; Liu, Deguang; Ge, Zhaohong; Wang, Da; Dai, Xinjia; Yi, Zhihao; Meng, Xiuxiang

2016-07-18

Phenotypic plasticity has recently been considered a powerful means of adaptation, but its relationships with corresponding life-history characters and plant specialization levels of insects have been controversial. To address the issues, Sitobion avenae clones from three plants in two areas were compared. Varying amounts of life-history trait plasticity were found among S. avenae clones on barley, oat and wheat. In most cases, developmental durations and their corresponding plasticities were found to be independent, and fecundities and their plasticities were correlated characters instead. The developmental time of first instar nymphs for oat and wheat clones, but not for barley clones, was found to be independent from its plasticity, showing environment-specific effects. All correlations between environments were found to be positive, which could contribute to low plasticity in S. avenae. Negative correlations between trait plasticities and fitness of test clones suggest that lower plasticity could have higher adaptive value. Correlations between plasticity and specialization indices were identified for all clones, suggesting that plasticity might evolve as a by-product of adaptation to certain environments. The divergence patterns of life-history plasticities in S. avenae, as well as the relationships among plasticity, specialization and fitness, could have significant implications for evolutionary ecology of this aphid.

A cost–benefit analysis of acclimation to low irradiance in tropical rainforest tree seedlings: leaf life span and payback time for leaf deployment

PubMed Central

Coste, Sabrina; Roggy, Jean-Christophe; Schimann, Heidy; Epron, Daniel; Dreyer, Erwin

2011-01-01

The maintenance in the long run of a positive carbon balance under very low irradiance is a prerequisite for survival of tree seedlings below the canopy or in small gaps in a tropical rainforest. To provide a quantitative basis for this assumption, experiments were carried out to determine whether construction cost (CC) and payback time for leaves and support structures, as well as leaf life span (i) differ among species and (ii) display an irradiance-elicited plasticity. Experiments were also conducted to determine whether leaf life span correlates to CC and payback time and is close to the optimal longevity derived from an optimization model. Saplings from 13 tropical tree species were grown under three levels of irradiance. Specific-CC was computed, as well as CC scaled to leaf area at the metamer level. Photosynthesis was recorded over the leaf life span. Payback time was derived from CC and a simple photosynthesis model. Specific-CC displayed only little interspecific variability and irradiance-elicited plasticity, in contrast to CC scaled to leaf area. Leaf life span ranged from 4 months to >26 months among species, and was longest in seedlings grown under lowest irradiance. It was always much longer than payback time, even under the lowest irradiance. Leaves were shed when their photosynthesis had reached very low values, in contrast to what was predicted by an optimality model. The species ranking for the different traits was stable across irradiance treatments. The two pioneer species always displayed the smallest CC, leaf life span, and payback time. All species displayed a similar large irradiance-elicited plasticity. PMID:21511904

Overview of Facial Plastic Surgery and Current Developments

PubMed Central

Chuang, Jessica; Barnes, Christian; Wong, Brian J. F.

2016-01-01

Facial plastic surgery is a multidisciplinary specialty largely driven by otolaryngology but includes oral maxillary surgery, dermatology, ophthalmology, and plastic surgery. It encompasses both reconstructive and cosmetic components. The scope of practice for facial plastic surgeons in the United States may include rhinoplasty, browlifts, blepharoplasty, facelifts, microvascular reconstruction of the head and neck, craniomaxillofacial trauma reconstruction, and correction of defects in the face after skin cancer resection. Facial plastic surgery also encompasses the use of injectable fillers, neural modulators (e.g., BOTOX Cosmetic, Allergan Pharmaceuticals, Westport, Ireland), lasers, and other devices aimed at rejuvenating skin. Facial plastic surgery is a constantly evolving field with continuing innovative advances in surgical techniques and cosmetic adjunctive technologies. This article aims to give an overview of the various procedures that encompass the field of facial plastic surgery and to highlight the recent advances and trends in procedures and surgical techniques. PMID:28824978

Assessment of floating plastic debris in surface water along the Seine River.

PubMed

Gasperi, Johnny; Dris, Rachid; Bonin, Tiffany; Rocher, Vincent; Tassin, Bruno

2014-12-01

This study is intended to examine the quality and quantity of floating plastic debris in the River Seine through use of an extensive regional network of floating debris-retention booms; it is one of the first attempts to provide reliable information on such debris at a large regional scale. Plastic debris represented between 0.8% and 5.1% of total debris collected by weight. A significant proportion consisted of food wrappers/containers and plastic cutlery, probably originating from voluntary or involuntary dumping, urban discharges and surface runoff. Most plastic items are made of polypropylene, polyethylene and, to a lesser extent, polyethylene terephthalate. By extrapolation, some 27 tons of floating plastic debris are intercepted annually by this network; corresponding to 2.3 g per Parisian inhabitant per year. Such data could serve to provide a first evaluation of floating plastic inputs conveyed by rivers. Copyright © 2014 Elsevier Ltd. All rights reserved.

Plastic strain is a mixture of avalanches and quasireversible deformations: Study of various sizes

NASA Astrophysics Data System (ADS)

Szabó, Péter; Ispánovity, Péter Dusán; Groma, István

2015-02-01

The size dependence of plastic flow is studied by discrete dislocation dynamical simulations of systems with various amounts of interacting dislocations while the stress is slowly increased. The regions between avalanches in the individual stress curves as functions of the plastic strain were found to be nearly linear and reversible where the plastic deformation obeys an effective equation of motion with a nearly linear force. For small plastic deformation, the mean values of the stress-strain curves obey a power law over two decades. Here and for somewhat larger plastic deformations, the mean stress-strain curves converge for larger sizes, while their variances shrink, both indicating the existence of a thermodynamical limit. The converging averages decrease with increasing size, in accordance with size effects from experiments. For large plastic deformations, where steady flow sets in, the thermodynamical limit was not realized in this model system.

Marine pollution. Plastic waste inputs from land into the ocean.

PubMed

Jambeck, Jenna R; Geyer, Roland; Wilcox, Chris; Siegler, Theodore R; Perryman, Miriam; Andrady, Anthony; Narayan, Ramani; Law, Kara Lavender

2015-02-13

Plastic debris in the marine environment is widely documented, but the quantity of plastic entering the ocean from waste generated on land is unknown. By linking worldwide data on solid waste, population density, and economic status, we estimated the mass of land-based plastic waste entering the ocean. We calculate that 275 million metric tons (MT) of plastic waste was generated in 192 coastal countries in 2010, with 4.8 to 12.7 million MT entering the ocean. Population size and the quality of waste management systems largely determine which countries contribute the greatest mass of uncaptured waste available to become plastic marine debris. Without waste management infrastructure improvements, the cumulative quantity of plastic waste available to enter the ocean from land is predicted to increase by an order of magnitude by 2025. Copyright © 2015, American Association for the Advancement of Science.

Spatio-temporal changes in agrochemical inputs and the risk assessment before and after the Grain-For-Green Policy in China.

PubMed

Wang, Xiuhong

2013-02-01

China's Grain-For-Green Policy (GFGP) of returning marginal cropland to forest or grassland is one of the most important large-scale initiatives to combat land degradation in its ecologically vulnerable regions. In order to maintain and increase crop production from decreasing areas of cropland, substantial spatio-temporal changes in agrochemical inputs have occurred, which have strongly influenced the ecological and environmental status of land in China. Based on the agrochemical inputs (chemical fertilizer, pesticide, plastic sheeting, and agricultural diesel oil) at the provincial level between 1993 and 2009, cluster analysis and gravity center modeling were used to trace these spatio-temporal changes. A regional comparative study was also undertaken to investigate the changes in the relative size of agrochemical inputs in the eastern, central, and western regions of China. It was found that the agrochemical inputs increased considerably at the nation level after the GFGP, which in order of increasing rate were: plastic sheeting > agricultural diesel oil > pesticide > chemical fertilizer. The gravity centers of agrochemical inputs moved substantially towards the northwest or west during the latter period of GFGP and regional comparative analysis showed that the agrochemical inputs increased substantially in the western region between 2004 and 2009. The ecological degradation caused by the expansion of the area devoted to crop production in the western region and the potential risk of agricultural non-point pollution caused by the increasing agrochemical inputs are the main factors restricting this area's sustainable development.

Strategies for tonal and atonal musical interpretation in blind and normally sighted children: an fMRI study.

PubMed

Guerrero Arenas, Coral; Hidalgo Tobón, Silvia S; Dies Suarez, Pilar; Barragán Pérez, Eduardo; Castro Sierra, Eduardo; García, Julio; de Celis Alonso, Benito

2016-04-01

Early childhood is known to be a period when cortical plasticity phenomena are at a maximum. Music is a stimulus known to modulate these mechanisms. On the other hand, neurological impairments like blindness are also known to affect cortical plasticity. Here, we address how tonal and atonal musical stimuli are processed in control and blind young children. We aimed to understand the differences between the two groups when processing this physiological information. Atonal stimuli produced larger activations in cerebellum, fusiform, and temporal lobe structures than tonal. In contrast, tonal stimuli induced larger frontal lobe representations than atonal. Control participants presented large activations in cerebellum, fusiform, and temporal lobe. A correlation/connectivity study showed that the blind group incorporated larger amounts of perceptual information (somatosensory and motor) into tonal processing through the function of the anterior prefrontal cortex (APC). They also used the visual cortex in conjunction with the Wernicke's area to process this information. In contrast, controls processed sound with perceptual stimuli from auditory cortex structures (including Wernicke's area). In this case, information was processed through the dorsal posterior cingulate cortex and not the APC. The orbitofrontal cortex also played a key role for atonal interpretation in this group. Wernicke's area, known to be involved in speech, was heavily involved for both groups and all stimuli. The two groups presented clear differences in strategies for music processing, with very different recruitment of brain regions.

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

PubMed

Miehe, C; Teichtmeister, S; Aldakheel, F

2016-04-28

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

Experimental study of microstructure changes due to low cycle fatigue of a steel nanocrystallised by Surface Mechanical Attrition Treatment (SMAT)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sun, Z.

Electron Backscatter Diffraction technique is used to characterize the microstructure of 316L steel generated by Surface Mechanical Attrition Treatment (SMAT) before and after low cycle fatigue tests. A grain size gradient is generated from the top surface to the interior of the samples after SMAT so that three main regions can be distinguished below the treated surface: (i) the ultra-fine grain area within 5 μm under the top surface with preferably oriented grains, (ii) the intermediate area where the original grains are partially transformed, and (iii) the edge periphery area where the original grains are just mechanically deformed with themore » presence of plastic slips. Fatigue tests show that cyclic loading does not change the grain orientation spread and does not activate any plastic slip in the ultra-fine grain top surface area induced by SMAT. On the opposite, in the plastically SMAT affected region including the intermediate area and the edge periphery area, new slip systems are activated by low cycle fatigue while the grain orientation spread is increased. These results represent a first very interesting step towards the characterization and understanding of mechanical mechanisms involved during the fatigue of a grain size gradient material. - Highlights: •LCF tests are carried out on specimens processed by SMAT. •EBSD is used to investigate microstructural changes induced by LCF. •A grain size gradient is generated by SMAT from surface to the bulk of the fatigue samples. •New slip systems are activated by LCF and GOS is increased in plastically deformed region. •However, these phenomena are not observed in the top surface ultra-fine grain area.« less

Synaptic plasticity in drug reward circuitry.

PubMed

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.

Presence of plastic particles in waterbirds faeces collected in Spanish lakes.

PubMed

Gil-Delgado, J A; Guijarro, D; Gosálvez, R U; López-Iborra, G M; Ponz, A; Velasco, A

2017-01-01

Plastic intake by marine vertebrates has been widely reported, but information about its presence in continental waterfowl is scarce. Here we analyzed faeces of waterbirds species (European coot, Fulica atra, mallard, Anas platyrhynchos and shelduck, Tadorna tadorna) for plastic debris in five wetlands in Central Spain. We collected 89 faeces of shelduck distributed in four lakes, 43.8% of them presented plastic remnants. Sixty percent of 10 faeces of European coot and 45% of 40 faeces of mallard contained plastic debris. Plastic debris found was of two types, threads and fragments, and were identified as remnants of plastic objects used in agricultural fields surrounding the lakes. Differences in prevalence of plastic in faeces, number of plastic pieces per excrement and size of the plastic pieces were not statistically significant between waterfowl species. Thus, our results suggest that plastic may also be frequently ingested by waterfowl in continental waters, at least in our study area. Future studies should address this potential problem for waterbird conservation in other wetlands to evaluate the real impact of this pollutant on waterbirds living in inland water. Copyright © 2016 Elsevier Ltd. All rights reserved.

Body Topography Parcellates Human Sensory and Motor Cortex.

PubMed

Kuehn, Esther; Dinse, Juliane; Jakobsen, Estrid; Long, Xiangyu; Schäfer, Andreas; Bazin, Pierre-Louis; Villringer, Arno; Sereno, Martin I; Margulies, Daniel S

2017-07-01

The cytoarchitectonic map as proposed by Brodmann currently dominates models of human sensorimotor cortical structure, function, and plasticity. According to this model, primary motor cortex, area 4, and primary somatosensory cortex, area 3b, are homogenous areas, with the major division lying between the two. Accumulating empirical and theoretical evidence, however, has begun to question the validity of the Brodmann map for various cortical areas. Here, we combined in vivo cortical myelin mapping with functional connectivity analyses and topographic mapping techniques to reassess the validity of the Brodmann map in human primary sensorimotor cortex. We provide empirical evidence that area 4 and area 3b are not homogenous, but are subdivided into distinct cortical fields, each representing a major body part (the hand and the face). Myelin reductions at the hand-face borders are cortical layer-specific, and coincide with intrinsic functional connectivity borders as defined using large-scale resting state analyses. Our data extend the Brodmann model in human sensorimotor cortex and suggest that body parts are an important organizing principle, similar to the distinction between sensory and motor processing. © The Author 2017. Published by Oxford University Press.

Regulatory mechanisms link phenotypic plasticity to evolvability

PubMed Central

van Gestel, Jordi; Weissing, Franz J.

2016-01-01

Organisms have a remarkable capacity to respond to environmental change. They can either respond directly, by means of phenotypic plasticity, or they can slowly adapt through evolution. Yet, how phenotypic plasticity links to evolutionary adaptability is largely unknown. Current studies of plasticity tend to adopt a phenomenological reaction norm (RN) approach, which neglects the mechanisms underlying plasticity. Focusing on a concrete question – the optimal timing of bacterial sporulation – we here also consider a mechanistic approach, the evolution of a gene regulatory network (GRN) underlying plasticity. Using individual-based simulations, we compare the RN and GRN approach and find a number of striking differences. Most importantly, the GRN model results in a much higher diversity of responsive strategies than the RN model. We show that each of the evolved strategies is pre-adapted to a unique set of unseen environmental conditions. The regulatory mechanisms that control plasticity therefore critically link phenotypic plasticity to the adaptive potential of biological populations. PMID:27087393

Plastic debris in Mediterranean seabirds.

PubMed

Codina-García, Marina; Militão, Teresa; Moreno, Javier; González-Solís, Jacob

2013-12-15

Plastic debris is often ingested by marine predators and can cause health disorders and even death. We present the first assessment of plastic ingestion in Mediterranean seabirds. We quantified and measured plastics accumulated in the stomach of 171 birds from 9 species accidentally caught by longliners in the western Mediterranean from 2003 to 2010. Cory's shearwaters (Calonectris diomedea) showed the highest occurrence (94%) and large numbers of small plastic particles per affected bird (on average N = 15.3 ± 24.4 plastics and mass = 23.4 ± 49.6 mg), followed by Yelkouan shearwaters (Puffinus yelkouan, 70%, N = 7.0 ± 7.9, 42.1 ± 100.0 mg), Balearic shearwaters (Puffinus mauretanicus, 70%, N = 3.6 ± 2.9, 5.5 ± 9.7 mg) and the rest of species (below 33%, N = 2.7, 113.6 ± 128.4 mg). Plastic characteristics did not differ between sexes and were not related to the physical condition of the birds. Our results point out the three endemic and threatened shearwater species as being particularly exposed to plastic accumulation.

Economic analysis of the future growth of cosmetic surgery procedures.

PubMed

Liu, Tom S; Miller, Timothy A

2008-06-01

The economic growth of cosmetic surgical and nonsurgical procedures has been tremendous. Between 1992 and 2005, annual U.S. cosmetic surgery volume increased by 725 percent, with over $10 billion spent in 2005. It is unknown whether this growth will continue for the next decade and, if so, what impact it will it have on the plastic surgeon workforce. The authors analyzed annual U.S. cosmetic surgery procedure volume reported by the American Society of Plastic Surgeons (ASPS) National Clearinghouse of Plastic Surgery Statistics between 1992 and 2005. Reconstructive plastic surgery volume was not included in the analysis. The authors analyzed the ability of economic and noneconomic variables to predict annual cosmetic surgery volume. The authors also used growth rate analyses to construct models with which to predict the future growth of cosmetic surgery. None of the economic and noneconomic variables were a significant predictor of annual cosmetic surgery volume. Instead, based on current compound annual growth rates, the authors predict that total cosmetic surgery volume (surgical and nonsurgical) will exceed 55 million annual procedures by 2015. ASPS members are projected to perform 299 surgical and 2165 nonsurgical annual procedures. Non-ASPS members are projected to perform 39 surgical and 1448 nonsurgical annual procedures. If current growth rates continue into the next decade, the future demand in cosmetic surgery will be driven largely by nonsurgical procedures. The growth of surgical procedures will be met by ASPS members. However, meeting the projected growth in nonsurgical procedures could be a potential challenge and a potential area for increased competition.

What is driving range expansion in a common bat? Hints from thermoregulation and habitat selection.

PubMed

Ancillotto, Leonardo; Budinski, Ivana; Nardone, Valentina; Di Salvo, Ivy; Corte, Martina Della; Bosso, Luciano; Conti, Paola; Russo, Danilo

2018-06-02

Human-induced alterations often lead to changes in the geographical range of plants and animals. While modelling exercises may contribute to understanding such dynamics at large spatial scales, they rarely offer insights into the mechanisms that prompt the process at a local scale. Savi's pipistrelle (Hypsugo savii) is a vespertilionid bat widespread throughout the Mediterranean region. The species' recent range expansion towards northeastern Europe is thought to be induced by urbanization, yet no study actually tested this hypothesis, and climate change is a potential alternative driver. In this radio-telemetry study, set in the Vesuvius National Park (Campania region, Southern Italy) we provide insights into the species' thermal physiology and foraging ecology and investigate their relationships with potential large-scale responses to climate, and land use changes. Specifically, we test whether H. savii i) exploits urbanisation through a selection of urban areas for roosting and foraging, and ii) tolerates heatwaves (a proxy for thermophily) through a plastic use of thermoregulation. Tolerance to heatwaves would be consistent with the observation that the species' geographic range is not shifting but expanding northwards. Tracked bats roosted mainly in buildings but avoided urban habitats while foraging, actively selecting non-intensive farmland and natural wooded areas. Hypsugo savii showed tolerance to heat, reaching the highest body temperature ever recorded for a free-ranging bat (46.5 °C), and performing long periods of overheating. We conclude that H. savii is not a strictly synurbic species because it exploits urban areas mainly for roosting, and avoids them for foraging: this questions the role of synurbization as a range expansion driver. On the other hand, the species' extreme heat tolerance and plastic thermoregulatory behaviour represent winning traits to cope with heatwaves typical of climate change-related weather fluctuations. Copyright © 2018 Elsevier B.V. All rights reserved.

Foliar nitrogen, phosphorus and potassium content in trees in environmentally toxic plastic industry area.

PubMed

Sett, Rupnarayan; Soni, Bhawna

2013-04-01

In plants, nitrogen deficiency causes stunted growth and chlorosis or yellowing of the leaves due to decreased levels of chlorophyll, while excess nitrogen uptake may cause dark green overly vigorous foliage which may have increased susceptibility to disease and insect attacks. Phosphorus is an important nutrient in crop production, since many soils in their native state do not have sufficient available phosphorus to maximize crop yield. Potassium deficiency may cause necrosis or interveinal chlorosis. Plastics are synthetic or semi-synthetic moldable organic solids that are organic polymers of high molecular mass, most commonly derived from petrochemicals; these polymers are based on chains of carbon atoms alone or with oxygen, sulfur, or nitrogen. Plastic is a non- biodegradable major toxic pollutant. It pollutes earth and leads to air pollution and water pollution. Merely there is any safe way to dispose the hazardous plastic wastes. The study was targeted to estimate foliar level of NPK content of three plant species, viz. Cassia tora (Herb), Ailanthus excelsa (Tree) and Dalbergia sissoo (Tree) from polluted areas associated to polythene-industries as well as control areas having least pollution, where all the parameters were found to be higher than the control experiments.

Plastic pollution in five urban estuaries of KwaZulu-Natal, South Africa.

PubMed

Naidoo, Trishan; Glassom, David; Smit, Albertus J

2015-12-15

Monitoring plastic concentrations in estuaries is vital in assessing the magnitude of terrestrial inputs to oceanic environments. Data on plastics ≤ 5 mm in estuaries are scant. This study determined microplastic levels within five estuaries along the Durban coastline and on intervening beaches. Plastics were isolated from estuarine sediment, beach sediment and the surface water of each estuary and characterised. Sediment at the Bayhead area of Durban harbour had the highest average plastic concentrations (745.4 ± 129.7 particles per 500 ml) and an attenuating concentration trend away from the city centre was found. Prevailing south to north longshore drift was hypothesised to result in plastic accumulation on the northern shores of beaches with estuarine effluents, however, this was not found. Fragments composed the largest percent of plastics (59%) found in Bayhead, whereas fibres dominated other estuaries with proportions ranging from 38% of total plastics in the uMgeni estuary to 66% in the Mdloti. Copyright © 2015 Elsevier Ltd. All rights reserved.

Room-Temperature and Solution-Processable Cu-Doped Nickel Oxide Nanoparticles for Efficient Hole-Transport Layers of Flexible Large-Area Perovskite Solar Cells.

PubMed

He, Qiqi; Yao, Kai; Wang, Xiaofeng; Xia, Xuefeng; Leng, Shifeng; Li, Fan

2017-12-06

Flexible perovskite solar cells (PSCs) using plastic substrates have become one of the most attractive points in the field of thin-film solar cells. Low-temperature and solution-processable nanoparticles (NPs) enable the fabrication of semiconductor thin films in a simple and low-cost approach to function as charge-selective layers in flexible PSCs. Here, we synthesized phase-pure p-type Cu-doped NiO x NPs with good electrical properties, which can be processed to smooth, pinhole-free, and efficient hole transport layers (HTLs) with large-area uniformity over a wide range of film thickness using a room-temperature solution-processing technique. Such a high-quality inorganic HTL allows for the fabrication of flexible PSCs with an active area >1 cm 2 , which have a power conversion efficiency over 15.01% without hysteresis. Moreover, the Cu/NiO x NP-based flexible devices also demonstrate excellent air stability and mechanical stability compared to their counterpart fabricated on the pristine NiO x films. This work will contribute to the evolution of upscaling flexible PSCs with a simple fabrication process and high device performances.

Knowledge and perception of plastic surgery among tertiary education students in Enugu, South-East Nigeria.

PubMed

Isiguzo, C M; Nwachukwu, C D

2016-01-01

Knowledge, perception, and acceptance of plastic surgery among any population are influenced by channel of presentation. A good understanding of the public awareness will define the way plastic surgery services will be provided. To assess the knowledge, awareness of availability, and acceptance of plastic surgery practice in Enugu, South East Nigeria. A questionnaire-based prospective study. The electronic media is the most common medium of awareness. Less than half the sample knew about the existence of plastic surgeons in Enugu even though a large proportion was aware of the existence of plastic surgery as a specialty. The concentration of plastic surgeons in a center is directly related to awareness of plastic surgery services in that facility. The most common esthetic procedure done by a plastic surgeon in Enugu is tattoo removal and scar refashioning. Orthopedic surgeons are thought to be key players in the management of burn patients as much as the plastic surgeons due to the "SIGNPOST EFFECT." The level of awareness is high in the sampled population with associated increase in acceptance of its practice and willing utilization. All public hospitals should be encouraged to employ the services of plastic surgeons. Appropriate branding of specialized hospitals where plastic surgery service is available will advance the practice significantly.

The complex interaction between marine debris and toxic chemicals in the ocean.

PubMed

Engler, Richard E

2012-11-20

Marine debris, especially plastic debris, is widely recognized as a global environmental problem. There has been substantial research on the impacts of plastic marine debris, such as entanglement and ingestion. These impacts are largely due to the physical presence of plastic debris. In recent years there has been an increasing focus on the impacts of toxic chemicals as they relate to plastic debris. Some plastic debris acts as a source of toxic chemicals: substances that were added to the plastic during manufacturing leach from plastic debris. Plastic debris also acts as a sink for toxic chemicals. Plastic sorbs persistent, bioaccumulative, and toxic substances (PBTs), such as polychlorinated biphenyls (PCBs) and dioxins, from the water or sediment. These PBTs may desorb when the plastic is ingested by any of a variety of marine species. This broad look at the current research suggests that while there is significant uncertainty and complexity in the kinetics and thermodynamics of the interaction, plastic debris appears to act as a vector transferring PBTs from the water to the food web, increasing risk throughout the marine food web, including humans. Because of the extremely long lifetime of plastic and PBTs in the ocean, prevention strategies are vital to minimizing these risks.

Origin of intraformational folds in the Jurassic Todilto Limestone, Ambrosia Lake uranium mining district, McKinley and Valencia counties, New Mexico

USGS Publications Warehouse

Green, M.W.

1982-01-01

The Todilto Limestone of Middle Jurassic age in the Ambrosia Lake uranium mining district of McKinley and Valencia Counties, New Mexico, is the host formation for numerous small- to medium-sized uranium deposits in joints, shear zones, and fractures within small- to large-scale intraformational folds. The folds probably were formed as a result of differential sediment loading when eolian sand dunes of the overlying Summerville Formation of Middle Jurassic age migrated over soft, chemically precipitated, lime muds of the Todilto shortly after their deposition in a regressive, mixed fresh and saline lacustrine or marine environment of deposition. Encroachment of Summerville eolian dunes over soft Todilto lime muds was apparently a local phenomenon and was restricted to postulated beltlike zones which trended radially across the Todilto coastline toward the receding body of water. Intraformational folding is believed to be confined to the pathways of individual eolian dunes or clusters of dunes within the dune belts. During the process of sediment loading by migrating sand dunes, layers of Todilto lime mud were differentially compacted, contorted, and dewatered, producing both small- and large-scale plastic deformation structures, including convolute laminations, mounds, rolls, folds, and small anticlines and synclines. With continued compaction and dewatering, the mud, in localized areas, reached a point of desaturation at which sediment plasticity was lost. Prolonged loading by overlying dune sands thus caused faulting, shearing, fracturing, and jointing of contorted limestone beds. These areas or zones of deformation within the limestone became the preferred sites of epigenetic uranium mineralization because of the induced transmissivity created by sediment rupture. Along most of the prograding Todilto coastline, adjacent to the eolian dune belts, both interdune and coastal sabkha environments dominated during Todilto-Summerville time. Sediments in coastal areas consisted mainly of clay, silt, sandy silt, and very fine-grained sand, which was apparently derived from the winnowing of the finer grained fraction of sediment from adjacent dune fields during periods of eolian activity. Most of the sabkha sediments were probably carried in airborne suspension to the low-lying, ground-water-saturated coastal areas, where they were deposited as relatively uniform blanket-like layers. Deposition of sabkha deposits was apparently slow and uniform over most of the Todilto coastal areas and crested only small-scale deformation features in underlying Todilto rocks. Large-scale deformation features and uranium deposits are both notably absent in the Todilto where it is overlain by finer textured sabkha deposits in the Summerville.

Plastic Accumulation in the Mediterranean Sea

PubMed Central

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

Design Enhancements to Facilitate a Sustainable and Energy Efficient Dining Facility (DFAC) in a Contingency Environment

DTIC Science & Technology

2014-09-01

resources, and generate large amounts of food and solid waste daily. Almost all Contingency Basecamp (CB) DFACs provide individual paper and plastic ware...which is costly in terms of purchase, transportation, and disposal. This work analyzed the effects of replacing paper and plastic ware with...reusable materials, and of adding industrial dishwashers to re- duce the logistical burden of using paper and plastic ware. Additional en- hancements

Determining Crack Tip Field Parameters for Elastic-Plastic Materials via an Estimation Scheme

DTIC Science & Technology

1981-07-01

of the Materials Laboratory was the Project Monitor for this study of the application of the Nonlinear Fracture Mechanics (NLFM) parameters to the...fracture mechanics (LEFM) is applicable . If the plastic zone size is large, compared to the case of small scale yielding, LEFM is not applicable . The...above HRR field equations are applicable only for the case of stationary cracks. 2.2 PARAMETER DETERMINATION For elastic-plastic materials, the

Slip Continuity in Explicit Crystal Plasticity Simulations Using Nonlocal Continuum and Semi-discrete Approaches

DTIC Science & Technology

2013-01-01

Based Micropolar Single Crystal Plasticity: Comparison of Multi - and Single Criterion Theories. J. Mech. Phys. Solids 2011, 59, 398–422. ALE3D ...element boundaries in a multi -step constitutive evaluation (Becker, 2011). The results showed the desired effects of smoothing the deformation field...Implementation The model was implemented in the large-scale parallel, explicit finite element code ALE3D (2012). The crystal plasticity

Relaxation of the single-slip condition in strain-gradient plasticity

PubMed Central

Anguige, Keith; Dondl, Patrick W.

2014-01-01

We consider the variational formulation of both geometrically linear and geometrically nonlinear elasto-plasticity subject to a class of hard single-slip conditions. Such side conditions typically render the associated boundary-value problems non-convex. We show that, for a large class of non-smooth plastic distortions, a given single-slip condition (specification of Burgers vectors) can be relaxed by introducing a microstructure through a two-stage process of mollification and lamination. The relaxed model can be thought of as an aid to simulating macroscopic plastic behaviour without the need to resolve arbitrarily fine spatial scales. PMID:25197243

Relaxation of the single-slip condition in strain-gradient plasticity.

PubMed

Anguige, Keith; Dondl, Patrick W

2014-09-08

We consider the variational formulation of both geometrically linear and geometrically nonlinear elasto-plasticity subject to a class of hard single-slip conditions. Such side conditions typically render the associated boundary-value problems non-convex. We show that, for a large class of non-smooth plastic distortions, a given single-slip condition (specification of Burgers vectors) can be relaxed by introducing a microstructure through a two-stage process of mollification and lamination. The relaxed model can be thought of as an aid to simulating macroscopic plastic behaviour without the need to resolve arbitrarily fine spatial scales.

Cosmetic surgery in times of recession: macroeconomics for plastic surgeons.

PubMed

Krieger, Lloyd M

2002-10-01

Periods of economic downturn place special demands on the plastic surgeon whose practice involves a large amount of cosmetic surgery. When determining strategy during difficult economic times, it is useful to understand the macroeconomic background of these downturns and to draw lessons from businesses in other service industries. Business cycles and monetary policy determine the overall environment in which plastic surgery is practiced. Plastic surgeons can take both defensive and proactive steps to maintain their profits during recessions and to prepare for the inevitable upturn. Care should also be taken when selecting pricing strategy during economic slowdowns.

Cyclic steady states in diffusion-induced plasticity with applications to lithium-ion batteries

NASA Astrophysics Data System (ADS)

Peigney, Michaël

2018-02-01

Electrode materials in lithium-ion batteries offer an example of medium in which stress and plastic flow are generated by the diffusion of guest atoms. In such a medium, deformation and diffusion are strongly coupled processes. For designing electrodes with improved lifetime and electro-mechanical efficiency, it is crucial to understand how plasticity and diffusion evolve over consecutive charging-recharging cycles. With such questions in mind, this paper provides general results for the large-time behavior of media coupling plasticity with diffusion when submitted to cyclic chemo-mechanical loadings. Under suitable assumptions, we show that the stress, the plastic strain rate, the chemical potential and the flux of guest atoms converge to a cyclic steady state which is largely independent of the initial state. A special emphasis is laid on the special case of elastic shakedown, which corresponds to the situation where the plastic strain stops evolving after a sufficiently large number of cycles. Elastic shakedown is expected to be beneficial for the fatigue behavior and - in the case of lithium-ion batteries - for the electro-chemical efficiency. We provide a characterization of the chemo-mechanical loadings for which elastic shakedown occurs. Building on that characterization, we suggest a general method for designing structures in such fashion that they operate in the elastic shakedown regime, whatever the initial state is. An attractive feature of the proposed method is that incremental analysis of the fully coupled plasticity-diffusion problem is avoided. The results obtained are applied to the model problem of a battery electrode cylinder particle under cyclic charging. Closed-form expressions are obtained for the set of charging rates and charging amplitudes for which elastic shakedown occurs, as well as for the corresponding cyclic steady states of stress, lithium concentration and chemical potential. Some results for a spherical particle are also presented.

Herbaceous plant species invading natural areas tend to have stronger adaptive root foraging than other naturalized species

PubMed Central

Keser, Lidewij H.; Visser, Eric J. W.; Dawson, Wayne; Song, Yao-Bin; Yu, Fei-Hai; Fischer, Markus; Dong, Ming; van Kleunen, Mark

2015-01-01

Although plastic root-foraging responses are thought to be adaptive, as they may optimize nutrient capture of plants, this has rarely been tested. We investigated whether nutrient-foraging responses are adaptive, and whether they pre-adapt alien species to become natural-area invaders. We grew 12 pairs of congeneric species (i.e., 24 species) native to Europe in heterogeneous and homogeneous nutrient environments, and compared their foraging responses and performance. One species in each pair is a USA natural-area invader, and the other one is not. Within species, individuals with strong foraging responses, measured as plasticity in root diameter and specific root length, had a higher biomass. Among species, the ones with strong foraging responses, measured as plasticity in root length and root biomass, had a higher biomass. Our results therefore suggest that root foraging is an adaptive trait. Invasive species showed significantly stronger root-foraging responses than non-invasive species when measured as root diameter. Biomass accumulation was decreased in the heterogeneous vs. the homogeneous environment. In aboveground, but not belowground and total biomass, this decrease was smaller in invasive than in non-invasive species. Our results show that strong plastic root-foraging responses are adaptive, and suggest that it might aid in pre-adapting species to becoming natural-area invaders. PMID:25964790

Effects of sex and seasonality on the song control system and FoxP2 protein expression in black-capped chickadees (Poecile atricapillus).

PubMed

Phillmore, Leslie S; MacGillivray, Heather L; Wilson, K Ryan; Martin, Stephanie

2015-02-01

Plasticity in behavior is mirrored by corresponding plasticity in the brain in many songbird species. In some species, song system nuclei (Phillmore et al. [2006]: J Neurobiol 66:1002-1010) are larger in birds in breeding condition than birds in nonbreeding condition, possibly due to increased vocal output in spring. FOXP2, a transcription factor associated with language expression and comprehension in humans and song learning in songbirds, also shows plasticity. FoxP2 expression in songbird Area X, a region important for sensorimotor integration, is related to developmental and adult vocal plasticity (Teramitsu et al. [2010]: J Neurosci 24:3152-3163, Chen et al. [2013], J Exp Biol 216:3682-3692). In this study, we examined whether sex and breeding condition affects both song control system volume (HVC, X) and FoxP2 protein expression in black-capped chickadees (Poecile atricapillus). HVC volume was larger in males in breeding condition than males in nonbreeding condition, but there were no sex differences. In contrast, Area X volume was larger in males than females, regardless of breeding condition, likely reflecting that male and female chickadees produce learned chick-a-dee calls year round, but output of the learned song increases in breeding males. FoxP2 protein levels did not differ between sexes or breeding condition when calculated as a ratio of labeled cells in Area X to labeled cells in the surrounding striato-pallium, however, absolute density of FoxP2 in both regions was higher in males than in females. This may indicate that chickadees maintain a level of FoxP2 necessary for plasticity year-round, but males have greater potential for plasticity compared to females. © 2014 Wiley Periodicals, Inc.

Quality of water sources used as drinking water in a Brazilian peri-urban area.

PubMed

Razzolini, Maria Tereza Pepe; Günther, Wanda Maria Risso; Peternella, Francisca Alzira Dos Santos; Martone-Rocha, Solange; Bastos, Veridiana Karmann; Santos, Thaís Filomena da Silva; Cardoso, Maria Regina Alves

2011-04-01

The objective of this paper was to assess bacteriological quality of drinking water in a peri-urban area located in the Metropolitan Region of São Paulo, Brazil. A total of 89 water samples were collected from community plastic tanks and 177 water samples from wells were collected bimonthly, from September 2007 to November 2008, for evaluating bacteriological parameters including: Escherichia coli, Enterococcus and heterotrophic plate count (HPC). Clostridium perfringens was investigated in a subsample (40 samples from community plastic tank and 40 from wells). E. coli was present in 5 (5.6%) samples from community plastic tanks (2.0 - 5.1x10(4) MPN/100mL) and in 70 (39.5%) well samples (2.0 - 8.6x10(4) MPN/100mL). Thus, these samples were not in accordance with the Brazilian Regulation. Enterococcus was detected in 20 (22.5%) samples of the community plastic tanks (1 to 79 NC/100mL) and in 142 (80.2%) well samples (1 to >200 NC/100mL). C. perfringens was detected in 5 (12.5%) community plastic tanks samples and in 35 (87.5%) wells samples (2.2 to >16 MPN/100mL). HPC were above 500 CFU/mL in 5 (5.6%) waters from community plastic tanks. In wells samples, the HPC ranged from <1 to 1.6x10(4) CFU/mL. The residual chlorine did not attend the standard established in the drinking water legislation (0.2 mg/L), except in 20 (22.5%) samples. These results confirm the vulnerability of the water supply systems in this peri-urban area what is clearly a public health concern.

Proper Accounting for Surface Area to Solution Volume Ratios in Exaggerated Extractions.

PubMed

Jenke, Dennis R; Rabinow, Barrett E

2017-01-01

When drug products contact plastic manufacturing components, packaging systems, and/or delivery devices, leachables from the plastics can accumulate in the drug product, potentially affecting its key quality attributes. Given practical issues associated with screening drug products for leachables, potential leachables are frequently surfaced as extractables revealed in extraction studies. To facilitate extractables discovery and identification and to shorten extraction times, extraction studies can be exaggerated and/or accelerated. One means of exaggerating an extraction is to increase the test article's extracted surface area to extraction solution volume ratio (SA/V), as it is generally accepted that an extractable's concentration in an extract is proportional to SA/V in a 1 to 1 manner. However, as the relationship between an extractable's concentration and SA/V depends on the extractable's plastic/solvent partition coefficient (k p/l ), the effect of SA/V on the extractable's concentrations can be either under- or over-estimated if a 1 to 1 proportion is used. This article presents the theoretical relationship between SA/V, concentration, and k p/l ; illustrates theory with a case study; and suggests proper exaggeration strategies. LAY ABSTRACT: When drug products are manufactured, stored, or delivered in systems that contain plastics, substances can be leached from the plastics and remain in the drug product, where they might affect the product's key quality attributes. To discover and identify these leached substances, the plastics are extracted under laboratory conditions and the extracts are appropriately tested. To facilitate this process, extracts may be generated under laboratory conditions that exaggerate or accelerate the drug product's clinical conditions of manufacturing or use. The proper use of the ratio of the extracted item's surface area to the volume of the extracting solution as an exaggeration parameter is discussed in this paper. © PDA, Inc. 2017.

The Relationship Between Geographic Access to Plastic Surgeons and Breast Reconstruction Rates Among Women Undergoing Mastectomy for Cancer.

PubMed

Bauder, Andrew R; Gross, Cary P; Killelea, Brigid K; Butler, Paris D; Kovach, Stephen J; Fox, Justin P

2017-03-01

Despite a national health care policy requiring payers to cover breast reconstruction, rates of postmastectomy reconstruction are low, particularly among minority populations. We conducted this study to determine if geographic access to a plastic surgeon impacts breast reconstruction rates. Using 2010 inpatient and ambulatory surgery data from 10 states, we identified adult women who underwent mastectomy for breast cancer. Data were aggregated to the health service area (HSA) level and hierarchical generalized linear models were used to risk-standardize breast reconstruction rates (RSRR) across HSAs. The relationship between an HSA's RSRR and plastic surgeon density (surgeons/100,000 population) was quantified using correlation coefficients. The final cohort included 22,997 patients across 134 HSAs. There was substantial variation in plastic surgeon density (median, 1.4 surgeons/100,000; interquartile range, [0.0-2.6]/100,000) and the use of breast reconstruction (median RSRR, 43.0%; interquartile range, [29.9%-62.8%]) across HSAs. Higher plastic surgeon density was positively correlated with breast reconstruction rates (correlation coefficient = 0.66, P < 0.001) and inversely related to time between mastectomy and reconstruction (correlation coefficient = -0.19, P < 0.001). Non-white and publicly insured women were least likely to undergo breast reconstruction overall. Among privately insured patients, racial disparities were noted in high surgeon density areas (white = 79.0% vs. non-white = 63.3%; P < 0.001) but not in low surgeon density areas (34.4% vs 36.5%; P = 0.70). The lack of geographic access to a plastic surgeon serves as a barrier to breast reconstruction and may compound disparities in care associated with race and insurance status. Future efforts to improve equitable access should consider strategies to ensure access to appropriate clinical expertise.

Analysis of soft magnetic materials by electron backscatter diffraction as a powerful tool

NASA Astrophysics Data System (ADS)

Schuller, David; Hohs, Dominic; Loeffler, Ralf; Bernthaler, Timo; Goll, Dagmar; Schneider, Gerhard

2018-04-01

The current work demonstrates that electron backscatter diffraction (EBSD) is a powerful and versatile characterization technique for investigating soft magnetic materials. The properties of soft magnets, e.g., magnetic losses strongly depend on the materials chemical composition and microstructure, including grain size and shape, texture, degree of plastic deformation and elastic strain. In electrical sheet stacks for e-motor applications, the quality of the machined edges/surfaces of each individual sheet is of special interest. Using EBSD, the influence of the punching process on the microstructure at the cutting edge is quantitatively assessed by evaluating the crystallographic misorientation distribution of the deformed grains. Using an industrial punching process, the maximum affected deformation depth is determined to be 200 - 300 μm. In the case of laser cutting, the affected deformation depth is determined to be approximately zero. Reliability and detection limits of the developed EBSD approach are evaluated on non-affected sample regions and model samples containing different indentation test bodies. A second application case is the investigation of the recrystallization process during the annealing step of soft magnetic composites (SMC) toroids produced by powder metallurgy as a function of compaction pressure, annealing parameters and powder particle size. With increasing pressure and temperature, the recrystallized area fraction (e.g., grains with crystallographic misorientations < 3°) increases from 71 % (200 MPa, 800°C) to 90% (800 MPa, 800°C). Recrystallization of the compacted powder material starts at the particle boundaries or areas with existing plastic deformation. The progress of recrystallization is visualized as a function of time and of different particle to grain size distributions. Here, large particles with coarse internal grain structures show a favorable recrystallization behavior which results in large bulk permeability of up to 600 - 700 and lower amount of residual misorientations (>3°).

What do plastic surgeons do?

PubMed

Park, A J; Scerri, G V; Benamore, R; McDiarmid, J G; Lamberty, B G

1998-06-01

The image of plastic surgery as portrayed by the media is of concern to all plastic surgeons. In order to assess knowledge about the specialty, a questionnaire was devised and given to five groups of participants: general practitioners, medical students, nurses, plastic surgical out-patient attendees, and the general public. The results revealed that general practitioners, nurses and medical students in the Cambridge area are, on the whole, knowledgeable about the role of plastic surgery. However, the general public are not so well educated and 23.7% of them could not think of five conditions treated by plastic surgeons, and felt that burns and cosmetic problems were the commonest conditions dealt with. Improved liaison with general practitioners, other specialties and more teaching of undergraduates, coupled with more effective promotion of the skills on offer might permit better use to be made of the specialty.

78 FR 5290 - Approval and Promulgation of Air Quality Implementation Plans; Maryland; Reasonably Available...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-01-25

...: Paper, film, and foil coatings; industrial cleaning solvents; miscellaneous metal and plastic parts... solvents; (3) miscellaneous metal and plastic parts coatings; (4) large appliance coatings; (5) offset... protection, Air pollution control, Incorporation by reference, Intergovernmental relations, Ozone, Reporting...

Study on Mechanical Properties of Concrete Using Plastic Waste as an Aggregate

NASA Astrophysics Data System (ADS)

Jaivignesh, B.; Sofi, A.

2017-07-01

Disposal of large quantity of plastic causes land, water and air pollution etc.., so a study is conducted to recycle the plastic in concrete. This work investigates about the replacement of natural aggregate with non-biodegradable plastic aggregate made up of mixed plastic waste in concrete. Several tests are conducted such as compressive strength of cube, split tensile strength of cylinder, flexural strength test of prism to identify the properties and behavior of concrete using plastic aggregate. Replacement of fine aggregate weight by 10%, 15%, 20% with Plastic fine (PF) aggregate and for each replacement of fine aggregate 15%, 20%, 25% of coarse aggregate replacement also conducted with Plastic Coarse(PC) aggregate. In literatures reported that the addition of plastic aggregate in concrete causes the reduction of strength in concrete due to poor bonding between concrete and plastic aggregate, so addition of 0.3% of steel fiber by weight of cement in concrete is done to improve the concrete strength. Totally 60 cubes, 60 cylinders and 40 prisms are casted to identify the compressive strength, split tensile strength and flexural strength respectively. Casted specimens are tested at 7 and 28 days. The identified results from concrete using plastic aggregate are compared with conventional concrete. Result shows that reduction in mechanical properties of plastic aggregate added concrete. This reduction in strength is mainly due to poor bond strength between cement and plastic aggregate.

Stability of total nutrient admixtures with lipid injectable emulsions in glass versus plastic packaging.

PubMed

Driscoll, David F; Silvestri, Anthony P; Bistrian, Bruce R; Mikrut, Bernard A

2007-02-15

The physical stability of two emulsions compounded as part of a total nutrient admixture (TNA) was studied in lipids packaged in either glass or plastic containers. Five weight-based adult TNA formulations that were designed to meet the full nutritional needs of adults with body weights between 40 and 80 kg were studied. Triplicate preparations of each TNA were assessed over 30 hours at room temperature by applying currently proposed United States Pharmacopeia (USP) criteria for mean droplet diameter, large-diameter tail, and globule-size distribution (GSD) for lipid injectable emulsions. In accordance with conditions set forth in USP chapter 729, the higher levels of volume-weighted percent of fat exceeding 5 microm (PFAT(5)) should not exceed 0.05% of the total lipid concentration. Significant differences were noted among TNA admixtures based on whether the lipid emulsion product was manufactured in glass or plastic. The plastic-contained TNAs failed the proposed USP methods for large-diameter fat globules in all formulations from the outset, and 60% had significant growth in large-diameter fat globules over time. In contrast, glass-contained TNAs were stable throughout and in all cases would have passed proposed USP limits. Certain lipid injectable emulsions packaged in plastic containers have baseline abnormal GSD profiles compared with those packaged in glass containers. When used to compound TNAs, the abnormal profile worsens and produces less stable TNAs than those compounded with lipid injectable emulsions packaged in glass containers.

Plastics disassembly versus bulk recycling: engineering design for end-of-life electronics resource recovery.

PubMed

Rios, Pedro; Stuart, Julie Ann; Grant, Ed

2003-12-01

Annual plastic flows through the business and consumer electronics manufacturing supply chain include nearly 3 billion lb of high-value engineering plastics derived from petroleum. The recovery of resource value from this stream presents critical challenges in areas of materials identification and recycling process design that demand new green engineering technologies applied together with life cycle assessment and ecological supply chain analysis to create viable plastics-to-plastics supply cycles. The sustainable recovery of potentially high-value engineering plastics streams requires that recyclers either avoid mixing plastic parts or purify later by separating smaller plastic pieces created in volume reduction (shredding) steps. Identification and separation constitute significant barriers in the plastics-to-plastics recycling value proposition. In the present work, we develop a model that accepts randomly arriving electronic products to study scenarios by which a recycler might identify and separate high-value engineering plastics as well as metals. Using discrete eventsimulation,we compare current mixed plastics recovery with spectrochemical plastic resin identification and subsequent sorting. Our results show that limited disassembly with whole-part identification can produce substantial yields in separated streams of recovered engineering thermoplastics. We find that disassembly with identification does not constitute a bottleneck, but rather, with relatively few workers, can be configured to pull the process and thus decrease maximum staging space requirements.

Quasistatic Evolution in Perfect Plasticity for General Heterogeneous Materials

NASA Astrophysics Data System (ADS)

Solombrino, Francesco

2014-04-01

Inspired by some recent developments in the theory of small-strain heterogeneous elastoplasticity, we both revisit and generalize the formulation of the quasistatic evolutionary problem in perfect plasticity given by Francfort and Giacomini (Commun Pure Appl Math, 65:1185-1241, 2012). We show that their definition of the plastic dissipation measure is equivalent to an abstract one, where it is defined as the supremum of the dualities between the deviatoric parts of admissible stress fields and the plastic strains. By means of this abstract definition, a viscoplastic approximation and variational techniques from the theory of rate-independent processes give the existence of an evolution satisfying an energy-dissipation balance and consequently Hill's maximum plastic work principle for an abstract and very large class of yield conditions.

Household scale of greenhouse design in Merauke

NASA Astrophysics Data System (ADS)

Alahudin, Muchlis; Widarnati, Indah; Luh Sri Suryaningsih, Ni

2018-05-01

Merauke is one of the areas that still use conventional methods in agriculture, The agricultural business does not run the maximum during the year because agricultural products quite difficult to obtain in the market. In the rainy season, the intensity of rain is very high, the water condition is abundant and hard to be channeled due to topography/soil contour conditions average, otherwise in the dry season the water is quite difficult to obtain. The purpose of this research is to compare the thermal conditions between greenhouse with auvplastic and plastic bottle roof.This research is experimental, measurement of thermal conditions in Greenhouse using measuring weather station.Greenhouse design with Quonset type with area of 24 m2The result of this research are greenhouse with paranet + UV plastic roof has an average temperature of 28.7 °C, 70.4% humidity and 0.5 m/s wind speed, while the greenhouse with paranet + plastic bottle roof has an average temperature of 26, 2 °C, humidity 66.4% and wind speed 0.9 m/s. Conclusion is Greenhouse with paranet + plastic bottle roof more thermally comfortable than greenhouse with paranet + UV plastic roof.

A Systematic Review of the Role of Robotics in Plastic and Reconstructive Surgery-From Inception to the Future.

PubMed

Dobbs, Thomas D; Cundy, Olivia; Samarendra, Harsh; Khan, Khurram; Whitaker, Iain Stuart

2017-01-01

The use of robots in surgery has become commonplace in many specialties. In this systematic review, we report on the current uses of robotics in plastic and reconstructive surgery and looks to future roles for robotics in this arena. A systematic literature search of Medline, EMBASE, and Scopus was performed using appropriate search terms in order to identify all applications of robot-assistance in plastic and reconstructive surgery. All articles were reviewed by two authors and a qualitative synthesis performed of those articles that met the inclusion criteria. The systematic review and results were conducted and reported in accordance with the Preferred Reporting Items for Systematic Reviews and Meta Analysis (PRISMA) guidelines. A total of 7,904 articles were identified for title and abstract review. Sixty-eight studies met the inclusion criteria. Robotic assistance in plastic and reconstructive surgery is still in its infancy, with areas such as trans-oral robotic surgery and microvascular procedures the dominant areas of interest currently. A number of benefits have been shown over conventional open surgery, such as improved access and greater dexterity; however, these must be balanced against disadvantages such as the lack of haptic feedback and cost implications. The feasibility of robotic plastic surgery has been demonstrated in several specific indications. As technology, knowledge, and skills in this area improve, these techniques have the potential to contribute positively to patient and provider experience and outcomes.

Study of the plastic zone around the ligament of thin sheet D.E.N.T specimen subjected to tensile

NASA Astrophysics Data System (ADS)

Djebali, S.; Larbi, S.; Bilek, A.

2015-03-01

One of the assumptions of Cotterell and Reddel's method of the essential work of fracture determination is the existence of a fracture process zone surrounded by an outer plastic zone extending to the whole ligament before crack initiation. To verify this hypothesis we developed a method based on micro hardness. The hardness values measured in the domain surrounding the tensile fracture area of ST-37-2 steel sheet D.E.N.T specimens confirm the existence of the two plastic zones. The extension of the plastic deformations to the whole ligament before the crack initiation and the circular shape of the outer plastic zone are revealed by the brittle coating method.

Floating macro-litter along the Mediterranean French coast: Composition, density, distribution and overlap with cetacean range.

PubMed

Di-Méglio, Nathalie; Campana, Ilaria

2017-05-15

This study investigated the composition, density and distribution of floating macro-litter along the Liguro-Provençal basin with respect to cetaceans presence. Survey transects were performed in summer between 2006 and 2015 from sailing vessels with simultaneous cetaceans observations. During 5171km travelled, 1993 floating items were recorded, widespread in the whole study area. Plastics was the predominant category, with bags/packaging always representing >45% of total items. Overall mean density (14.98 items/km 2 ) was stable with significant increase reported only in 2010-2011; monthly analysis showed lower litter densities in July-September, suggesting possible seasonal patterns. Kernel density estimation for plastics revealed ubiquitous distribution rather than high accumulation areas, mainly due to the circulation dynamics of this area. The presence range of cetaceans (259 sightings, 6 species) corresponded by ~50% with plastic distribution, indicating high potential of interaction, especially in the eastern part of the area, but effective risks for marine species might be underrepresented. Copyright © 2017 Elsevier Ltd. All rights reserved.

Plasticity in thermal tolerance has limited potential to buffer ectotherms from global warming.

PubMed

Gunderson, Alex R; Stillman, Jonathon H

2015-06-07

Global warming is increasing the overheating risk for many organisms, though the potential for plasticity in thermal tolerance to mitigate this risk is largely unknown. In part, this shortcoming stems from a lack of knowledge about global and taxonomic patterns of variation in tolerance plasticity. To address this critical issue, we test leading hypotheses for broad-scale variation in ectotherm tolerance plasticity using a dataset that includes vertebrate and invertebrate taxa from terrestrial, freshwater and marine habitats. Contrary to expectation, plasticity in heat tolerance was unrelated to latitude or thermal seasonality. However, plasticity in cold tolerance is associated with thermal seasonality in some habitat types. In addition, aquatic taxa have approximately twice the plasticity of terrestrial taxa. Based on the observed patterns of variation in tolerance plasticity, we propose that limited potential for behavioural plasticity (i.e. behavioural thermoregulation) favours the evolution of greater plasticity in physiological traits, consistent with the 'Bogert effect'. Finally, we find that all ectotherms have relatively low acclimation in thermal tolerance and demonstrate that overheating risk will be minimally reduced by acclimation in even the most plastic groups. Our analysis indicates that behavioural and evolutionary mechanisms will be critical in allowing ectotherms to buffer themselves from extreme temperatures. © 2015 The Author(s) Published by the Royal Society. All rights reserved.

Plasticity in thermal tolerance has limited potential to buffer ectotherms from global warming

PubMed Central

Gunderson, Alex R.; Stillman, Jonathon H.

2015-01-01

Global warming is increasing the overheating risk for many organisms, though the potential for plasticity in thermal tolerance to mitigate this risk is largely unknown. In part, this shortcoming stems from a lack of knowledge about global and taxonomic patterns of variation in tolerance plasticity. To address this critical issue, we test leading hypotheses for broad-scale variation in ectotherm tolerance plasticity using a dataset that includes vertebrate and invertebrate taxa from terrestrial, freshwater and marine habitats. Contrary to expectation, plasticity in heat tolerance was unrelated to latitude or thermal seasonality. However, plasticity in cold tolerance is associated with thermal seasonality in some habitat types. In addition, aquatic taxa have approximately twice the plasticity of terrestrial taxa. Based on the observed patterns of variation in tolerance plasticity, we propose that limited potential for behavioural plasticity (i.e. behavioural thermoregulation) favours the evolution of greater plasticity in physiological traits, consistent with the ‘Bogert effect’. Finally, we find that all ectotherms have relatively low acclimation in thermal tolerance and demonstrate that overheating risk will be minimally reduced by acclimation in even the most plastic groups. Our analysis indicates that behavioural and evolutionary mechanisms will be critical in allowing ectotherms to buffer themselves from extreme temperatures. PMID:25994676

Converting inert plastic waste into energetic materials: A study on the light-accelerated decomposition of plastic waste with the Fenton reaction.

PubMed

Chow, Cheuk-Fai; Wong, Wing-Leung; Chan, Ching-Wan; Chan, Chung-Sum

2018-05-01

Better treatment and management strategies than landfilling are needed to address the large quantities of unrecycled plastic waste generated by daily human activities. Waste-to-energy conversion is an ideal benchmark for developing future large-scale waste management technologies. The present study explores a new approach for producing energetic materials by converting inert plastic waste into energy (thermal and mechanical energies) via a light-controlled process through the simple chemical activation of plastic waste, including polyethylene, polypropylene, and polyvinyl chloride. The inert and non-polar polymer surfaces of the plastics were modified by generating a number of sulfonic groups (SO 3 - ) using chlorosulfuric acid, followed by grafting of Fe(III) catalyst onto the polymer chains to obtain activated polymer. Elemental analyses of these activated materials showed that the carbon-to-sulfur ratio ranged from 3:1 to 5:1. The FTIR spectra indicated the presence of CC bonds (v C=C : 1615-1630 cm -1 ) and SO bonds (v S=O : 1151-1167 cm -1 ) in the activated polymers after chemical reaction. These activated materials were energetic, as light could be used to convert them into thermal (1800-3200 J/g) and mechanical energies (380-560 kPa/g) using hydrogen peroxide as the oxidant under ambient conditions within 1 h. Copyright © 2018 Elsevier Ltd. All rights reserved.

Liquification and soft-sediment deformation in a limestone megabreccia: The Ayabacas giant collapse, Cretaceous, southern Peru

NASA Astrophysics Data System (ADS)

Callot, Pierre; Odonne, Francis; Sempere, Thierry

2008-12-01

In the back-arc basin of southern Peru, the bulk of the mid-Cretaceous carbonate platform collapsed near the Turonian-Coniacian boundary (~ 90-89 Ma), due to slope creation and resulting oversteepening. The resulting mass-wasting deposits, namely the Ayabacas Formation, consist of a megabreccia which is organised from NE to SW in relation with two major fault systems. Facies of sediment reworking (such as brecciation, liquification, sedimentary dykes and soft-sediment deformation) are described and four types of resedimentation facies are define. In the northeastern part of the study area, deposits mainly consist of a mixture of very heterometric clasts and blocks (millimetric to kilometric in size), mainly carbonate but also sandy-marly in nature, floating in sandy-marly matrix that exhibits features of liquification (sedimentary dykes and flows) and plastic deformation. Here, resedimentation facies are characterized by deformations and a brecciated facies at each observation scale (from aerial photographs to thin sections) and are therefore defined as fractal or multi-scale breccias. Some clasts and large amounts of the matrix were derived from the underlying clay-rich sandstones of the Murco Formation. These materials were prone to liquification and plastic deformation, allowing them to act as a sliding sole that facilitated the slides and the downslope movement of large limestone rafts. In the southwestern part of the study area, only limestone breccias are observed, in alternation with well-stratified levels. The sliding sole of plastically deformable siliciclastic sediments that previously acted as a lubricating layer was not present here, as materials were more deeply buried. Variations in the degree of sediment lithification from northeast to southwest are inferred to have existed before the collapse and also within the sedimentary succession in the northeastern part. In particular, limestones were well-cemented at the base of the carbonate succession and formed a cap that prevented water to escape from the underlying siliciclastic materials. Such a succession allowed the formation of limestone clasts and of a slide sole constituted by water-saturated siliciclastic materials. In the southern part of the study area, the slide surface was located within the Murco Formation in the upper part of the collapse and just above the Murco Formation downslope. The collapse was frontally confined as it was blocked downslope by a topographic high that folded the whole limestone succession. In the northern part of the study area, the slide surface was also within the Murco Formation in the upper part, but occurs within the limestone succession downslope, due to higher subsidence that buried the sediments more deeply. The compressional structures affecting the limestone succession in the south are not observed there, suggesting that the toe of the collapse was not blocked here.

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

PubMed

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.

Oncological screening for Bilateral Breast Reduction: a survey of practice variations in UK Breast and Plastics surgeons 2009.

PubMed

Hennedige, Anusha A; Kong, Tze Yean; Gandhi, Ashu

2011-07-01

Bilateral Breast Reduction (BBR) is a common procedure performed by Breast and Plastic surgeons in the UK. No consensus exists regarding preoperative screening for malignancy or for selective criteria for such screening. Preoperative BBR screening practices among UK Breast and Plastic surgeons are unknown. Ascertain the preoperative and postoperative BBR screening practices of UK Breast and Plastic surgeons. A questionnaire was posted to all 434 Breast and 335 Plastic surgeons in the UK. All results were analysed with relevant statistical methods. 64% of Breast surgeons and 72% of Plastic surgeons responded. 40% of Breast surgeons and 91% of Plastic surgeons perform BBR. Routine radiological screening: 92% Breast 41% Plastic (p < 0.05). Routine breast examination prior to BBR: 98% Breast 91% Plastic. Routine histology for BBR specimens: 96% Breast 90% Plastic. Selective screening of patients aged 30-40 years old: Breast 38% Plastic 10%. Selective screening of patients aged 40-50: Breast 78%, Plastic 53%. Selective screening of patients with strong family history of breast cancer: Breast 72%, Plastic 91%. Selective screening of patients with previous breast cancer: Breast 77%, Plastic 93%. There are significant differences in practice between UK Breast surgeons and Plastic surgeons in preoperative oncological screening for BBR. The large discrepancy in preoperative radiological screening, reflects a ubiquitous pro-screening ideology among Breast surgeons not prevalent among Plastic surgeons. These results will provoke debate towards the direction of consensus to ultimately reflect best practice. Copyright © 2010. Published by Elsevier Ltd.

Automated sorting of polymer flakes: fluorescence labeling and development of a measurement system prototype.

PubMed

Brunner, S; Fomin, P; Kargel, Ch

2015-04-01

The extensive demand and use of plastics in modern life is associated with a significant economical impact and a serious ecological footprint. The production of plastics involves a high energy consumption and CO2 emission as well as the large need for (limited) fossil resources. Due to the high durability of plastics, large amounts of plastic garbage is mounting in overflowing landfills (plus 9.6 million tons in Europe in the year 2012) and plastic debris is floating in the world oceans or waste-to-energy combustion releases even more CO2 plus toxic substances (dioxins, heavy metals) to the atmosphere. The recycling of plastic products after their life cycle can obviously contribute a great deal to the reduction of the environmental and economical impacts. In order to produce high-quality recycling products, mono-fractional compositions of waste polymers are required. However, existing measurement technologies such as near infrared spectroscopy show limitations in the sorting of complex mixtures and different grades of polymers, especially when black plastics are involved. More recently invented technologies based on mid-infrared, Raman spectroscopy or laser-aided spectroscopy are still under development and expected to be rather expensive. A promising approach to put high sorting purities into practice is to label plastic resins with unique combinations of fluorescence markers (tracers). These are incorporated into virgin resins during the manufacturing process at the ppm (or sub ppm) concentration level, just large enough that the fluorescence emissions can be detected with sensitive instrumentation but neither affect the visual appearance nor the mechanical properties of the polymers. In this paper we present the prototype of a measurement and classification system that identifies polymer flakes (mill material of a few millimeters size) located on a conveyor belt in real time based on the emitted fluorescence of incorporated markers. Classification performance and throughput were experimentally quantified using 3 different types of polymers (Polyoxymethylene (POM), Polybutylenterephthalat (PBT) and Acrylonitrile Styrene Acrylate (ASA)) in colored and uncolored form. Overall, 12 classes of plastic flakes were investigated in this study, where 11 classes were labeled with unique binary combinations of 4 fluorescence markers and class 12 includes unlabeled plastic flakes of various colors. From approx. 68,000 investigated flakes it was found that the developed measurement prototype system achieves an average sensitivity (true positive rate) of 99.4% and a precision (positive predictive value) of 99.5%, while being able to handle up to approx. 1800 flakes per second. Copyright © 2014 Elsevier Ltd. All rights reserved.

Targeting central plasticity: a new direction of finding painkillers.

PubMed

Zhuo, Min

2005-01-01

It is well documented that sensory transmission, including pain, receives endogenous inhibitory modulatory influences at dorsal horn of the spinal cord. Recent results, from behavioral to molecular studies, demonstrate that injury caused plastic changes in forebrain areas. In addition to encoding pain, these supraspinal areas may also affect pain transmission in the spinal cord level by activating "top-down" descending facilitatory systems. In this review, I provide review of evidence related to these new progresses, from human brain imaging to work from genetically mutant mice.

Analysis and Synthesis of Adaptive Neural Elements and Assemblies

DTIC Science & Technology

1989-12-19

examine the role of neuronal plasticity in learning. During the periodbetween August 1, 1988 and July 31, 1989, progress has been made in four areas...nonassociative and associative plasticity and to examine the role of neuronal plasticity in learning. During the period between August 1, 1988 and July 31...characteristics of the simulated /KS can be revealed by isolating a cAMP difference current, just as we have done experimentally. The properties of the simulated

75 FR 60333 - Hazardous Material; Miscellaneous Packaging Amendments

Federal Register 2010, 2011, 2012, 2013, 2014

2010-09-30

... minimum thickness requirements for remanufactured steel and plastic drums; (2) reinstate the previous... communication problem for emergency responders in that it may interfere with them discovering a large amount of... prescribed in Sec. 178.2(c). D. Minimum Thickness Requirement for Remanufactured Steel and Plastic Drums...

Detecting Plastic PFM-1 Butterfly Mines Using Thermal Infrared Sensing

NASA Astrophysics Data System (ADS)

Baur, J.; de Smet, T.; Nikulin, A.

2017-12-01

Remnant plastic-composite landmines, such as the mass-produced PFM-1, represent an ongoing humanitarian threat aggravated by high costs associated with traditional demining efforts. These particular unexploded ordnance (UXO) devices pose a challenge to conventional geophysical detection methods, due their plastic-body design and small size. Additionally, the PFM-1s represent a particularly heinous UXO, due to their low mass ( 25 lb) trigger limit and "butterfly" wing design, earning them the reputation of a "toy mine" - disproportionally impacting children across post-conflict areas. We developed a detection algorithm based on data acquired by a thermal infrared camera mounted to a commercial UAV to detect time-variable temperature difference between the PFM-1 and the surrounding environment. We present results of a field study focused on thermal detection and identification of the PFM-1 anti-personnel landmines from a remotely operated unmanned aerial vehicle (UAV). We conducted a series of field detection experiments meant to simulate the mountainous terrains where PFM-1 mines were historically deployed and remain in place. In our tests, 18 inert PFM-1 mines along with the aluminum KSF-1 casing were randomly dispersed to mimic an ellipsoidal minefield of 8-10 x 18-20 m dimensions in a de-vegetated rubble yard at Chenango Valley State Park (New York State). We collected multiple thermal infrared imagery datasets focused on these model minefields with the FLIR Vue Pro R attached to the 3DR Solo UAV flying at approximately at 2 m. We identified different environmental variables to constrain the optimal time of day and daily temperature variations to reveal presence of these plastic UXOs. We show that in the early-morning hours when thermal inertia is greatest, the PFM-1 mines can be detected based on their differential thermal inertia. Because the mines have statistically different temperatures than background and a characteristic shape, we were able to train a supervised learning algorithm to automate detection of the mines over large areas. We anticipate that following further development, this remote sensing method can aid in significantly reducing the cost and time associated with landmine remediation in post-conflict nations.

Selection and screening of microbial consortia for efficient and ecofriendly degradation of plastic garbage collected from urban and rural areas of Bangalore, India.

PubMed

Skariyachan, Sinosh; Megha, M; Kini, Meghna Niranjan; Mukund, Kamath Manali; Rizvi, Alya; Vasist, Kiran

2015-01-01

Industrialization and urbanization have led to massive accumulation of plastic garbage all over India. The persistence of plastic in soil and aquatic environment has become ecological threat to the metropolitan city such as Bangalore, India. Present study investigates an ecofriendly, efficient and cost-effective approach for plastic waste management by the screening of novel microbial consortia which are capable of degrading plastic polymers. Plastic-contaminated soil and water samples were collected from six hot spots of urban and rural areas of Bangalore. The plastic-degrading bacteria were enriched, and degradation ability was determined by zone of clearance method. The percentage of polymer degradation was initially monitored by weight loss method, and the main isolates were characterized by standard microbiology protocols. These isolates were used to form microbial consortia, and the degradation efficiency of the consortia was compared with individual isolate and known strains obtained from the Microbial Type Culture Collection (MTCC) and Gene Bank, India. One of the main enzymes responsible for polymer degradation was identified, and the biodegradation mechanism was hypothesized by bioinformatics studies. From this study, it is evident that the bacteria utilized the plastic polymer as a sole source of carbon and showed 20-50% weight reduction over a period of 120 days. The two main bacteria responsible for the degradation were microbiologically characterized to be Pseudomonas spp. These bacteria could grow optimally at 37 °C in pH 9.0 and showed 35-40% of plastic weight reduction over 120 days. These isolates were showed better degradation ability than known strains from MTCC. The current study further revealed that the microbial consortia formulated by combining Psuedomonas spp. showed 40 plastic weight reduction over a period of 90 days. Further, extracellular lipase, one of the main enzymes responsible for polymer degradation, was identified. The computational docking studies suggested that polyethylene glycol and polystyrene present in the plastics might have good interaction towards the microbial lipase with stable binding and interacting forces which probably could be one of the reasons for the degradative mechanisms.

Reassessing cortical reorganization in the primary sensorimotor cortex following arm amputation.

PubMed

Makin, Tamar R; Scholz, Jan; Henderson Slater, David; Johansen-Berg, Heidi; Tracey, Irene

2015-08-01

The role of cortical activity in generating and abolishing chronic pain is increasingly emphasized in the clinical community. Perhaps the most striking example of this is the maladaptive plasticity theory, according to which phantom pain arises from remapping of cortically neighbouring representations (lower face) into the territory of the missing hand following amputation. This theory has been extended to a wide range of chronic pain conditions, such as complex regional pain syndrome. Yet, despite its growing popularity, the evidence to support the maladaptive plasticity theory is largely based on correlations between pain ratings and oftentimes crude measurements of cortical reorganization, with little consideration of potential contributions of other clinical factors, such as adaptive behaviour, in driving the identified brain plasticity. Here, we used a physiologically meaningful measurement of cortical reorganization to reassess its relationship to phantom pain in upper limb amputees. We identified small yet consistent shifts in lip representation contralateral to the missing hand towards, but not invading, the hand area. However, we were unable to identify any statistical relationship between cortical reorganization and phantom sensations or pain either with this measurement or with the traditional Euclidian distance measurement. Instead, we demonstrate that other factors may contribute to the observed remapping. Further research that reassesses more broadly the relationship between cortical reorganization and chronic pain is warranted. © The Author (2015). Published by Oxford University Press on behalf of the Guarantors of Brain.

Switched-capacitor realization of presynaptic short-term-plasticity and stop-learning synapses in 28 nm CMOS

PubMed Central

Noack, Marko; Partzsch, Johannes; Mayr, Christian G.; Hänzsche, Stefan; Scholze, Stefan; Höppner, Sebastian; Ellguth, Georg; Schüffny, Rene

2015-01-01

Synaptic dynamics, such as long- and short-term plasticity, play an important role in the complexity and biological realism achievable when running neural networks on a neuromorphic IC. For example, they endow the IC with an ability to adapt and learn from its environment. In order to achieve the millisecond to second time constants required for these synaptic dynamics, analog subthreshold circuits are usually employed. However, due to process variation and leakage problems, it is almost impossible to port these types of circuits to modern sub-100nm technologies. In contrast, we present a neuromorphic system in a 28 nm CMOS process that employs switched capacitor (SC) circuits to implement 128 short term plasticity presynapses as well as 8192 stop-learning synapses. The neuromorphic system consumes an area of 0.36 mm2 and runs at a power consumption of 1.9 mW. The circuit makes use of a technique for minimizing leakage effects allowing for real-time operation with time constants up to several seconds. Since we rely on SC techniques for all calculations, the system is composed of only generic mixed-signal building blocks. These generic building blocks make the system easy to port between technologies and the large digital circuit part inherent in an SC system benefits fully from technology scaling. PMID:25698914

Micro-plastic ingestion by waterbirds from contaminated wetlands in South Africa.

PubMed

Reynolds, Chevonne; Ryan, Peter G

2018-01-01

Despite a large literature on the impacts of micro-plastic pollution in marine ecosystems, very little research has focused on these pollutants in freshwater ecosystems. Recently, however, a few studies have demonstrated that micro-plastic pollutants are ingested by freshwater taxa, including birds. To explore this potential environmental threat in African freshwater systems we quantified micro-plastic pollutants in the faeces and feather brushings of seven southern African duck species. We analysed 283 faecal samples and 408 feather brushings, and found that 5% of faecal samples and 10% of feather samples contained micro-plastic fibres. The presence and abundance of micro-fibres differed between sampling sites, with significantly higher amounts recorded for the site that received effluent from a sewage treatment facility. Additionally, micro-fibre presence differed across duck species, indicating that foraging behaviour affects plastic ingestion. Our study confirms that African freshwater ecosystems and the biodiversity they support are under threat from micro-plastic contamination. Copyright © 2017 Elsevier Ltd. All rights reserved.

Daily accumulation rates of marine debris on sub-Antarctic island beaches.

PubMed

Eriksson, Cecilia; Burton, Harry; Fitch, Stuart; Schulz, Martin; van den Hoff, John

2013-01-15

The worlds' oceans contain a large but unknown amount of plastic debris. We made daily collections of marine debris stranded at two sub-Antarctic islands to establish (a) physical causes of strandings, and (b) a sampling protocol to better estimate the oceans' plastic loading. Accumulation rates at some beaches were dependent on tide and onshore winds. Most of the 6389 items collected were plastic (Macquarie 95%, Heard 94%) and discarded or lost fishing gear comprised 22% of those plastic items. Stalked barnacles (Lepas spp.) were a regular attachment on Macquarie debris but not at Heard Island. The daily accumulation rate of plastic debris on Macquarie Island was an order of magnitude higher than that estimated from monthly surveys during the same 4 months in the previous 5 years. This finding suggests that estimates of the oceans' plastic loading are an order of magnitude too low. Copyright © 2012 Elsevier Ltd. All rights reserved.

What Can Plasticity Contribute to Insect Responses to Climate Change?

PubMed

Sgrò, Carla M; Terblanche, John S; Hoffmann, Ary A

2016-01-01

Plastic responses figure prominently in discussions on insect adaptation to climate change. Here we review the different types of plastic responses and whether they contribute much to adaptation. Under climate change, plastic responses involving diapause are often critical for population persistence, but key diapause responses under dry and hot conditions remain poorly understood. Climate variability can impose large fitness costs on insects showing diapause and other life cycle responses, threatening population persistence. In response to stressful climatic conditions, insects also undergo ontogenetic changes including hardening and acclimation. Environmental conditions experienced across developmental stages or by prior generations can influence hardening and acclimation, although evidence for the latter remains weak. Costs and constraints influence patterns of plasticity across insect clades, but they are poorly understood within field contexts. Plastic responses and their evolution should be considered when predicting vulnerability to climate change-but meaningful empirical data lag behind theory.

Plastic in the Thames: a river runs through it.

PubMed

Morritt, David; Stefanoudis, Paris V; Pearce, Dave; Crimmen, Oliver A; Clark, Paul F

2014-01-15

Although contamination of the marine ecosystems by plastics is becoming recognised as a serious pollution problem, there are few studies that demonstrate the contribution made by freshwater catchments. Over a three month period from September to December 2012, at seven localities in the upper Thames estuary, 8490 submerged plastic items were intercepted in eel fyke nets anchored to the river bed. Whilst there were significant differences in the numbers of items at these locations, the majority were some type of plastic. Additionally in excess of 20% of the litter items were components of sanitary products. The most contaminated sites were in the vicinity of sewage treatment works. While floating litter is visible, this study also demonstrates that a large unseen volume of submerged plastic is flowing into the marine environment. It is therefore important that this sub-surface component is considered when assessing plastic pollution input into the sea. Copyright © 2013 Elsevier Ltd. All rights reserved.

Export of Plastic Debris by Rivers into the Sea.

PubMed

Schmidt, Christian; Krauth, Tobias; Wagner, Stephan

2017-11-07

A substantial fraction of marine plastic debris originates from land-based sources and rivers potentially act as a major transport pathway for all sizes of plastic debris. We analyzed a global compilation of data on plastic debris in the water column across a wide range of river sizes. Plastic debris loads, both microplastic (particles <5 mm) and macroplastic (particles >5 mm) are positively related to the mismanaged plastic waste (MMPW) generated in the river catchments. This relationship is nonlinear where large rivers with  population-rich catchments delivering a disproportionately higher fraction of MMPW into the sea. The 10 top-ranked rivers transport 88-95% of the global load into the sea. Using MMPW as a predictor we calculate the global plastic debris inputs form rivers into the sea to range between 0.41 and 4 × 10 6 t/y. Due to the limited amount of data high uncertainties were expected and ultimately confirmed. The empirical analysis to quantify plastic loads in rivers can be extended easily by additional potential predictors other than MMPW, for example, hydrological conditions.

Plastic debris in the open ocean

PubMed Central

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

Plastic debris in the open ocean.

PubMed

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.

The incidence of plastic ingestion by fishes: from the prey's perspective.

PubMed

Carson, Henry S

2013-09-15

One of the primary threats to ocean ecosystems from plastic pollution is ingestion by marine organisms. Well-documented in seabirds, turtles, and marine mammals, ingestion by fish and sharks has received less attention until recently. We suggest that fishes of a variety of sizes attack drifting plastic with high frequency, as evidenced by the apparent bite marks commonly left behind. We examined 5518 plastic items from random plots on Kamilo Point, Hawai'i Island, and found 15.8% to have obvious signs of attack. Extrapolated to the entire amount of debris removed from the 15 km area, over 1.3 tons of plastic is attacked each year. Items with a bottle shape, or those blue or yellow in color, were attacked with a higher frequency. The triangular edges or punctures left by teeth ranged from 1 to 20 mm in width suggesting a variety of species attack plastic items. More research is needed to document the specific fishes and rates of plastic ingestion. Copyright © 2013 Elsevier Ltd. All rights reserved.

Tracking plastics in the Mediterranean: 2D Lagrangian model.

PubMed

Liubartseva, S; Coppini, G; Lecci, R; Clementi, E

2018-04-01

Drift of floating debris is studied with a 2D Lagrangian model with stochastic beaching and sedimentation of plastics. An ensemble of >10 10 virtual particles is tracked from anthropogenic sources (coastal human populations, rivers, shipping lanes) to environmental destinations (sea surface, coastlines, seabed). Daily analyses of ocean currents and waves provided by CMEMS at a horizontal resolution of 1/16° are used to force the plastics. High spatio-temporal variability in sea-surface plastic concentrations without any stable long-term accumulations is found. Substantial accumulation of plastics is detected on coastlines and the sea bottom. The most contaminated areas are in the Cilician subbasin, Catalan Sea, and near the Po River Delta. Also, highly polluted local patches in the vicinity of sources with limited circulation are identified. An inverse problem solution, used to quantify the origins of plastics, shows that plastic pollution of every Mediterranean country is caused primarily by its own terrestrial sources. Copyright © 2018 Elsevier Ltd. All rights reserved.

Incidence of plastic debris in Sooty Tern nests: A preliminary study on Trindade Island, a remote area of Brazil.

PubMed

de Souza Petersen, Elisa; Krüger, Lucas; Dezevieski, Alexandre; Petry, MariaVirginia; Montone, Rosalinda Carmela

2016-04-15

Plastic is abundant in the oceans, reaching pelagic zones away from continents. Here we present the first recordings of plastic used as nest material in Sooty Tern nests, on a remote oceanic island. We describe our findings in terms of quantity, size and color of plastic debris. A total of 78 plastics were noted in 54 nests. Four color categories were found: Blue, White, Green and Red. Blue fragments were the most frequent color, present three times as much as white debris. This pattern was present despite blue fragments being smaller and lighter. The plastic debris of lowest frequency were the larger and heavier pieces (red). To our knowledge this is the first record of plastic in Sooty Tern nests. Trindade Island is on an oceanic zone expected to accumulate garbage due to the dynamic ocean currents. Such findings call for a closer inspection of pollution in the Atlantic Ocean. Copyright © 2016 Elsevier Ltd. All rights reserved.

Risks of Plastic Debris: Unravelling Fact, Opinion, Perception, and Belief

PubMed Central

2017-01-01

Researcher and media alarms have caused plastic debris to be perceived as a major threat to humans and animals. However, although the waste of plastic in the environment is clearly undesirable for aesthetic and economic reasons, the actual environmental risks of different plastics and their associated chemicals remain largely unknown. Here we show how a systematic assessment of adverse outcome pathways based on ecologically relevant metrics for exposure and effect can bring risk assessment within reach. Results of such an assessment will help to respond to the current public worry in a balanced way and allow policy makers to take measures for scientifically sound reasons. PMID:28971682

Reproducing Kernel Particle Method in Plasticity of Pressure-Sensitive Material with Reference to Powder Forming Process

NASA Astrophysics Data System (ADS)

Khoei, A. R.; Samimi, M.; Azami, A. R.

2007-02-01

In this paper, an application of the reproducing kernel particle method (RKPM) is presented in plasticity behavior of pressure-sensitive material. The RKPM technique is implemented in large deformation analysis of powder compaction process. The RKPM shape function and its derivatives are constructed by imposing the consistency conditions. The essential boundary conditions are enforced by the use of the penalty approach. The support of the RKPM shape function covers the same set of particles during powder compaction, hence no instability is encountered in the large deformation computation. A double-surface plasticity model is developed in numerical simulation of pressure-sensitive material. The plasticity model includes a failure surface and an elliptical cap, which closes the open space between the failure surface and hydrostatic axis. The moving cap expands in the stress space according to a specified hardening rule. The cap model is presented within the framework of large deformation RKPM analysis in order to predict the non-uniform relative density distribution during powder die pressing. Numerical computations are performed to demonstrate the applicability of the algorithm in modeling of powder forming processes and the results are compared to those obtained from finite element simulation to demonstrate the accuracy of the proposed model.

[Experimental determination of the time-dependent extent of after-burning with reference to possibilities of the plastic surgery reconstruction of 3d degree burns].

PubMed

Bäumer, F; Henrich, H A; Ussmüller, J

1986-02-01

The present experiments try to answer the question as to the time-dependent extent of the after-burning process after full-thickness burn (third degree). For an early plastic surgical treatment it was of interest to determine the most early time of escharotomy. The time-dependent spreading of the after-burning area reached its maximum five days after the burn injury. The after-burning area was marked by intravenous injections of Patentblau which caused distinct intravital colouring. Subsequently no further progress could be observed. In the present experiments we suggest this time as the earliest time for plastic covering in case it would be dependent upon the end of the after-burning process.

Fouling assemblage of benthic plastic debris collected from Mersin Bay, NE Levantine coast of Turkey.

PubMed

Gündoğdu, Sedat; Çevik, Cem; Karaca, Serkan

2017-11-15

The Mediterranean is an ecosystem that faces more and more microplastic pollution every day. This causes the whole of the Mediterranean to face the negative effects of plastic pollution. This study examines the state of plastic debris and fouling organisms found on it in one of the areas most affected by plastic pollution, Mersin Bay. As a result, a total of 3.88kg plastic (mean=0,97kg; n=120; 2670item/km 2 ; 86,3kg/km 2 ) was collected and based on the ATR-FTIR analysis, it was determined that this total contained 9 types of plastics. 17 different fouling species belonging to 6 phylum (Annelida, Arthropoda, Bryozoa, Chordata, Cnidaria, Mollusca) 7 class and 11 order were discovered on plastics. Spirobranchus triqueter, Hydroides sp. and Neopycnodonte cochlear were the most abundant species. In the end, the example of Mersin Bay shows that plastic debris as a substrate can contain a very high diversity of life just like natural substrates. Copyright © 2017 Elsevier Ltd. All rights reserved.

Review of the partitioning of chemicals into different plastics: Consequences for the risk assessment of marine plastic debris.

PubMed

O'Connor, Isabel A; Golsteijn, Laura; Hendriks, A Jan

2016-12-15

Marine plastic debris are found worldwide in oceans and coastal areas. They degrade only slowly and contain chemicals added during manufacture or absorbed from the seawater. Therefore, they can pose a long-lasting contaminant source and potentially transfer chemicals to marine organisms when ingested. In order to assess their risk, the contaminant concentration in the plastics needs to be estimated and differences understood. We collected from literature plastic water partition coefficients of various organic chemicals for seven plastic types: polydimethylsiloxane (PDMS), high-density, low-density and ultra-high molecular weight polyethylene (LDPE, HDPE, UHMWPE), polystyrene (PS), polypropylene (PP), and polyvinyl chloride (PVC). Most data was available for PDMS (1060) and LDPE (220), but much less for the remaining plastics (73). Where possible, regression models were developed and the partitioning was compared between the different plastic types. The partitioning of chemicals follows the order of LDPE≈HDPE≥PP>PVC≈PS. Data describing the impact of weathering are urgently needed. Copyright © 2016 Elsevier Ltd. All rights reserved.

Correction of the post -- necking true stress -- strain data using instrumented nanoindentation

NASA Astrophysics Data System (ADS)

Romero Fonseca, Ivan Dario

The study of large plastic deformations has been the focus of numerous studies particularly in the metal forming processes and fracture mechanics fields. A good understanding of the plastic flow properties of metallic alloys and the true stresses and true strains induced during plastic deformation is crucial to optimize the aforementioned processes, and to predict ductile failure in fracture mechanics analyzes. Knowledge of stresses and strains is extracted from the true stress-strain curve of the material from the uniaxial tensile test. In addition, stress triaxiality is manifested by the neck developed during the last stage of a tensile test performed on a ductile material. This necking phenomenon is the factor responsible for deviating from uniaxial state into a triaxial one, then, providing an inaccurate description of the material's behavior after the onset of necking. The research of this dissertation is aimed at the development of a correction method for the nonuniform plastic deformation (post-necking) portion of the true stress-strain curve. The correction proposed is based on the well-known relationship between hardness and flow (yield) stress, except that instrumented nanoindentation hardness is utilized rather than conventional macro or micro hardness. Three metals with different combinations of strain hardening behavior and crystal structure were subjected to quasi-static tensile tests: power-law strain hardening low carbon G10180 steel (BCC) and electrolytic tough pitch copper C11000 (FCC), and linear strain hardening austenitic stainless steel S30400 (FCC). Nanoindentation hardness values, measured on the broken tensile specimen, were converted into flow stress values by means of the constraint factor C from Tabor's, the representative plastic strainepsilonr and the post-test true plastic strains measured. Micro Vickers hardness testing was carried out on the sample as well. The constraint factors were 5.5, 4.5 and 4.5 and the representative plastic strains were 0.028, 0.062 and 0.061 for G101800, C11000 and S30400 respectively. The established corrected curves relating post-necking flow stress to true plastic strain turned out to be well represented by a power-law function. Experimental results dictated that a unique single value for C and for epsilonr is not appropriate to describe materials with different plastic behaviors. Therefore, Tabor's equation, along with the representative plastic strain concept, has been misused in the past. The studied materials exhibited different nanohardness and plastic strain distributions due to their inherently distinct elasto-plastic response. The proposed post-necking correction separates out the effect of triaxiality on the uniaxial true stress-strain curve provided that the nanohardness-flow stress relationship is based on uniaxial values of stress. Some type of size effect, due to the microvoids at the tip of the neck, influenced nanohardness measurements. The instrumented nanoindentation technique proved to be a very suitable method to probe elasto-plastic properties of materials such as nanohardness, elastic modulus, and quasi-static strain rate sensitivity among others. Care should be taken when converting nanohardness to Vickers and vice versa due to their different area definition used. Nanohardness to Vickers ratio oscillated between 1.01 and 1.17.

Optical sensors based on plastic fibers.

PubMed

Bilro, Lúcia; Alberto, Nélia; Pinto, João L; Nogueira, Rogério

2012-01-01

The recent advances of polymer technology allowed the introduction of plastic optical fiber in sensor design. The advantages of optical metrology with plastic optical fiber have attracted the attention of the scientific community, as they allow the development of low-cost or cost competitive systems compared with conventional technologies. In this paper, the current state of the art of plastic optical fiber technology will be reviewed, namely its main characteristics and sensing advantages. Several measurement techniques will be described, with a strong focus on interrogation approaches based on intensity variation in transmission and reflection. The potential applications involving structural health monitoring, medicine, environment and the biological and chemical area are also presented.

Cellulose Nanofiber Composite Substrates for Flexible Electronics

Treesearch

Ronald Sabo; Jung-Hun Seo; Zhenqiang Ma

2012-01-01

Flexible electronics have a large number of potential applications including malleable displays and wearable computers. The current research into high-speed, flexible electronic substrates employs the use of plastics for the flexible substrate, but these plastics typically have drawbacks, such as high thermal expansion coefficients. Transparent films made from...

Chapter 2.3 Cellulose Nanofibril Composite Substrates for Flexible Electronics

Treesearch

Ronald Sabo; Jung-Hun Seo; Zhenqiang Ma

2013-01-01

Flexible electronics have a large number of potential applications, including malleable displays and wearable computers. Current research into high-speed, flexible electronic substrates uses plastics for the flexible substrate, but these plastics typically have drawbacks, such as high thermal expansion coefficients. Transparent films made from cellulose...

A summary of recent results from the GRAPES-3 experiment

NASA Astrophysics Data System (ADS)

Gupta, S. K.

2017-06-01

The GRAPES-3 experiment is a combination of a high density extensive air shower (EAS) array of nearly 400 plastic scintillator detectors, and a large 560 m2 area tracking muon telescope with an energy threshold Eμ >1 GeV. GRAPES-3 has been operating continuously in Ooty, India since 2000. By accurately correcting for the effects of atmospheric pressure and temperature, the muon telescope provides a high precision directional survey of the galactic cosmic ray (GCR) intensity. This telescope has been used to observe the acceleration of muons during thunderstorm events. The recent discovery of a transient weakening of the Earth's magnetic shield through the detection of a GCR burst was the highlight of the GRAPES-3 results. We have an ongoing major expansion activity to further enhance the capability of the GRAPES-3 muon telescope by doubling its area.

Ultrathin and lightweight organic solar cells with high flexibility

PubMed Central

Kaltenbrunner, Martin; White, Matthew S.; Głowacki, Eric D.; Sekitani, Tsuyoshi; Someya, Takao; Sariciftci, Niyazi Serdar; Bauer, Siegfried

2012-01-01

Application-specific requirements for future lighting, displays and photovoltaics will include large-area, low-weight and mechanical resilience for dual-purpose uses such as electronic skin, textiles and surface conforming foils. Here we demonstrate polymer-based photovoltaic devices on plastic foil substrates less than 2 μm thick, with equal power conversion efficiency to their glass-based counterparts. They can reversibly withstand extreme mechanical deformation and have unprecedented solar cell-specific weight. Instead of a single bend, we form a random network of folds within the device area. The processing methods are standard, so the same weight and flexibility should be achievable in light emitting diodes, capacitors and transistors to fully realize ultrathin organic electronics. These ultrathin organic solar cells are over ten times thinner, lighter and more flexible than any other solar cell of any technology to date. PMID:22473014

Features of structural response of mechanically loaded crystallites to irradiation

NASA Astrophysics Data System (ADS)

Korchuganov, Aleksandr V.

2015-10-01

A molecular dynamics method is employed to investigate the origin and evolution of plastic deformation in elastically deformed iron and vanadium crystallites due to atomic displacement cascades. Elastic stress states of crystallites result from different degrees of specimen deformation. Crystallites are deformed under constant-volume conditions. Atomic displacement cascades with the primary knock-on atom energy up to 50 keV are generated in loaded specimens. It is shown that irradiation may cause not only the Frenkel pair formation but also large-scale structural rearrangements outside the irradiated area, which prove to be similar to rearrangements proceeding by the twinning mechanism in mechanically loaded specimens.

Deformation mechanics of deep surface flaw cracks

NASA Technical Reports Server (NTRS)

Francis, P. H.; Nagy, A.; Beissner, R. E.

1972-01-01

A combined analytical and experimental program was conducted to determine the deformation characteristics of deep surface cracks in Mode I loading. An approximate plane finite element analysis was performed to make a parameter study on the influence of crack depth, crack geometry, and stress level on plastic zones, crack opening displacement, and back surface dimpling in Fe-3Si steel and 2219-T87 aluminum. Surface replication and profiling techniques were used to examine back surface dimple configurations in 2219-T87 aluminum. Interferometry and holography were used to evaluate the potential of various optical techniques to detect small surface dimples on large surface areas.

Nanosecond multi-pulse laser milling for certain area removal of metal coating on plastics surface

NASA Astrophysics Data System (ADS)

Zhao, Kai; Jia, Zhenyuan; Ma, Jianwei; Liu, Wei; Wang, Ling

2014-12-01

Metal coating with functional pattern on engineering plastics surface plays an important role in industry applications; it can be obtained by adding or removing certain area of metal coating on engineering plastics surface. However, the manufacturing requirements are improved continuously and the plastic substrate presents three-dimensional (3D) structure-many of these parts cannot be fabricated by conventional processing methods, and a new manufacturing method is urgently needed. As the laser-processing technology has many advantages like high machining accuracy and constraints free substrate structure, the machining of the parts is studied through removing certain area of metal coating based on the nanosecond multi-pulse laser milling. To improve the edge quality of the functional pattern, generation mechanism and corresponding avoidance strategy of the processing defects are studied. Additionally, a prediction model for the laser ablation depth is proposed, which can effectively avoid the existence of residual metal coating and reduces the damage of substrate. With the optimal machining parameters, an equiangular spiral pattern on copper-clad polyimide (CCPI) is machined based on the laser milling at last. The experimental results indicate that the edge of the pattern is smooth and consistent, the substrate is flat and without damage. The achievements in this study could be applied in industrial production.

Biocompatible Zr-Al-Fe bulk metallic glasses with large plasticity

NASA Astrophysics Data System (ADS)

Hua, NengBin; Li, Ran; Wang, JianFeng; Zhang, Tao

2012-09-01

In the present study, high-zirconium ternary Zr-Al-Fe bulk metallic glasses (BMGs) with low Young's modulus and good plasticity were developed. Zr75Al7.5Fe17.5 BMG exhibits a low Young's modulus of 70 GPa and high Poisson's ratio of 0.403. Pronounced plasticity was demonstrated under both compression and bending conditions for the BMGs. Furthermore, the alloys show high corrosion resistance in phosphate buffered solution. The combination of desirable mechanical and chemical properties implies potential for biomedical applications.

Characterizing wood-plastic composites via data-driven methodologies

Treesearch

John G. Michopoulos; John C. Hermanson; Robert Badaliance

2007-01-01

The recent increase of wood-plastic composite materials in various application areas has underlined the need for an efficient and robust methodology to characterize their nonlinear anisotropic constitutive behavior. In addition, the multiplicity of various loading conditions in structures utilizing these materials further increases the need for a characterization...

Plastic mistaken for prey by a colony-breeding Eleonora's falcon (Falco eleonorae) in the Mediterranean Sea, revealed by camera-trap.

PubMed

Steen, Ronny; Torjussen, Cathrine S; Jones, Dean W; Tsimpidis, Thodoris; Miliou, Anastasia

2016-05-15

Discarded plastic is known to be harmful for marine animals through ingestion and entanglement. Here we report the first documentation of Eleonora's falcons providing plastic waste to dependent nestlings. Eleonora's falcons breed colonially on sea cliffs and islets in areas of the Mediterranean Sea and the Canary Islands in which they normally feed their nestlings exclusively with small migratory birds. Copyright © 2016 Elsevier Ltd. All rights reserved.

New data aid estimate of ocean's plastic content

NASA Astrophysics Data System (ADS)

Wendel, JoAnna

2014-12-01

Experts estimate that 5.25 trillion plastic particles—weighing in at nearly 269,000 tons—are floating in the world's oceans. A new paper in the open access journal PLOS ONE (doi:10.1371/journal.pone.011191) about the abundance of plastic in the oceans combines data from 24 expeditions between 2007 and 2013. These expeditions cover all five subtropical gyres—areas of high pressure where seawater churns and sinks—as well as Australian coastal waters, the Bay of Bengal, and even the Mediterranean Sea.

BOOK REVIEW: Introduction to Computational Plasticity

NASA Astrophysics Data System (ADS)

Hartley, P.

2006-04-01

The use of computational modelling in all areas of science and engineering has in recent years escalated to the point where it underpins much of current research. However, the distinction must be made between computer systems in which no knowledge of the underlying computer technology or computational theory is required and those areas of research where the mastery of computational techniques is of great value, almost essential, for final year undergraduates or masters students planning to pursue a career in research. Such a field of research in the latter category is continuum mechanics, and in particular non-linear material behaviour, which is the core topic of this book. 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. Any lack of knowledge in this area however, is of no disadvantage as it serves only as an introduction and the book moves on quickly to continuum plasticity. 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 matrices with a clear explanation of their development, is a recurring, and commendable, feature of the book, which provides an invaluable introduction for those new to the subject. The chapter moves on from time-independent behaviour to introduce viscoplasticity and creep. Chapter three takes the theories of deformation another stage further to consider the problems associated with large deformation in which an important concept is the separation of the phenomenon into material stretch and rotation. The latter is crucial to allow correct measures of strain and stress to be developed in which the effects of rigid body rotation do not contribute to these variables. Hence, the introduction of 'objective' measures for stress and strain. These are described with reference to deformation gradients, which are clearly explained; however, the introduction of displacement gradients passes with little comment, although velocity gradients appear later in the chapter. The interpretation of different strain measures, e.g. Green--Lagrange and Almansi, is covered briefly, followed by a description of the spin tensor and its use in developing the objective Jaumann rate of stress. It is tempting here to suggest that a more complete description should be given together with other measures of strain and stress, of which there are several, but there would be a danger of changing the book from an `introduction' to a more comprehensive text, and examples of such exist already. Chapter four begins the process of developing the plasticity theories into a form suitable for inclusion in the finite-element method. The starting point is Hamilton's principle for equilibrium of a dynamic system. A very brief introduction to the finite-element method is then given, followed by the finite-element equilibrium equations and a description of how they are incorporated into Hamilton's principle. A useful clarification is provided by comparing tensor notation and the form normally used in finite-element expressions, i.e. Voigt notation. The chapter concludes with a brief overview of implicit integration methods, i.e. tangent stiffness, initial tangent stiffness and Newton Raphson. Chapter five deals with the more specialized topic of implicit and explicit integration of von Mises plasticity. One of the techniques described is the radial-return method which ensures that the stresses at the end of an increment of deformation always lie on the expanded yield surface. Although this method guarantees a solution it may not always be the most accurate for large deformation, this is one area where reference to alternative methods would have been a helpful addition. Chapter six continues with further detail of how the plasticity models may be incorporated into finite-element codes, with particular reference to the Abaqus package and the use of user-defined subroutines, introduced via a `UMAT' subroutine. This completes part I of the book. Part II focuses on plasticity models, each chapter dealing with a particular process or material model. For example, chapter seven deals with superplasticity, chapter eight with porous plasticity, chapter nine with creep and chapter ten with cyclic plasticity, creep and TMF. Examples of deep drawing, forming of titanium metal-matrix composites and creep damage are provided, together with further guidelines on the use of Abaqus to model these processes. Overall, the book is organised in a very logical and readable form. The use of simple one-dimensional examples, with full descriptions of tensors and vectors throughout the book, is particularly useful. It provides a good introduction to the topic, covering much of the theory and with applications to give a good grounding that can be taken further with more comprehensive advanced texts. An excellent starting point for anyone involved in research in computational plasticity.

Plastic particles in coastal pelagic ecosystems of the Northeast Pacific ocean.

PubMed

Doyle, Miriam J; Watson, William; Bowlin, Noelle M; Sheavly, Seba B

2011-02-01

The purpose of this study was to examine the distribution, abundance and characteristics of plastic particles in plankton samples collected routinely in Northeast Pacific ecosystems, and to contribute to the development of ideas for future research into the occurrence and impact of small plastic debris in marine pelagic ecosystems. Plastic debris particles were assessed from zooplankton samples collected as part of the National Oceanic and Atmospheric Administration's (NOAA) ongoing ecosystem surveys during two research cruises in the Southeast Bering Sea in the spring and fall of 2006 and four research cruises off the U.S. west coast (primarily off southern California) in spring, summer and fall of 2006, and in January of 2007. Nets with 0.505 mm mesh were used to collect surface samples during all cruises, and sub-surface samples during the four cruises off the west coast. The 595 plankton samples processed indicate that plastic particles are widely distributed in surface waters. The proportion of surface samples from each cruise that contained particles of plastic ranged from 8.75 to 84.0%, whereas particles were recorded in sub-surface samples from only one cruise (in 28.2% of the January 2007 samples). Spatial and temporal variability was apparent in the abundance and distribution of the plastic particles and mean standardized quantities varied among cruises with ranges of 0.004-0.19 particles/m³, and 0.014-0.209 mg dry mass/m³. Off southern California, quantities for the winter cruise were significantly higher, and for the spring cruise significantly lower than for the summer and fall surveys (surface data). Differences between surface particle concentrations and mass for the Bering Sea and California coast surveys were significant for pair-wise comparisons of the spring but not the fall cruises. The particles were assigned to three plastic product types: product fragments, fishing net and line fibers, and industrial pellets; and five size categories: <1 mm, 1-2.5 mm, >2.5-5 mm, >5-10 mm, and >10 mm. Product fragments accounted for the majority of the particles, and most were less than 2.5 mm in size. The ubiquity of such particles in the survey areas and predominance of sizes <2.5 mm implies persistence in these pelagic ecosystems as a result of continuous breakdown from larger plastic debris fragments, and widespread distribution by ocean currents. Detailed investigations of the trophic ecology of individual zooplankton species, and their encounter rates with various size ranges of plastic particles in the marine pelagic environment, are required in order to understand the potential for ingestion of such debris particles by these organisms. Ongoing plankton sampling programs by marine research institutes in large marine ecosystems are good potential sources of data for continued assessment of the abundance, distribution and potential impact of small plastic debris in productive coastal pelagic zones. © 2010 Elsevier Ltd. All rights reserved.

User-interactive electronic skin for instantaneous pressure visualization

NASA Astrophysics Data System (ADS)

Wang, Chuan; Hwang, David; Yu, Zhibin; Takei, Kuniharu; Park, Junwoo; Chen, Teresa; Ma, Biwu; Javey, Ali

2013-10-01

Electronic skin (e-skin) presents a network of mechanically flexible sensors that can conformally wrap irregular surfaces and spatially map and quantify various stimuli. Previous works on e-skin have focused on the optimization of pressure sensors interfaced with an electronic readout, whereas user interfaces based on a human-readable output were not explored. Here, we report the first user-interactive e-skin that not only spatially maps the applied pressure but also provides an instantaneous visual response through a built-in active-matrix organic light-emitting diode display with red, green and blue pixels. In this system, organic light-emitting diodes (OLEDs) are turned on locally where the surface is touched, and the intensity of the emitted light quantifies the magnitude of the applied pressure. This work represents a system-on-plastic demonstration where three distinct electronic components—thin-film transistor, pressure sensor and OLED arrays—are monolithically integrated over large areas on a single plastic substrate. The reported e-skin may find a wide range of applications in interactive input/control devices, smart wallpapers, robotics and medical/health monitoring devices.

Electric double-layer capacitors with tea waste derived activated carbon electrodes and plastic crystal based flexible gel polymer electrolytes

NASA Astrophysics Data System (ADS)

Suleman, M.; Deraman, M.; Othman, M. A. R.; Omar, R.; Hashim, M. A.; Basri, N. H.; Nor, N. S. M.; Dolah, B. N. M.; Hanappi, M. F. Y. M.; Hamdan, E.; Sazali, N. E. S.; Tajuddin, N. S. M.; Jasni, M. R. M.

2016-08-01

We report a novel configuration of symmetrical electric double-layer capacitors (EDLCs) comprising a plastic crystalline succinonitrile (SN) based flexible polymer gel electrolyte, incorporated with sodium trifluoromethane sulfonate (NaTf) immobilised in a host polymer poly (vinylidine fluoride-co-hexafluoropropylene) (PVdF-HFP). The cost-effective activated carbon powder possessing a specific surface area (SSA) of ~ 1700 m2g-1 containing a large proportion of meso-porosity has been derived from tea waste to use as supercapacitor electrodes. The high ionic conductivity (~3.6×10-3 S cm-1 at room temperature) and good electrochemical stability render the gel polymer electrolyte film a suitable candidate for the fabrication of EDLCs. The performance of the EDLCs has been tested by electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV), and galvanostatic charge-discharge studies. The performance of the EDLC cell is found to be promising in terms of high values of specific capacitance (~270 F g-1), specific energy (~ 36 Wh kg-1), and power density (~ 33 kW kg-1).

User-interactive electronic skin for instantaneous pressure visualization.

PubMed

Wang, Chuan; Hwang, David; Yu, Zhibin; Takei, Kuniharu; Park, Junwoo; Chen, Teresa; Ma, Biwu; Javey, Ali

2013-10-01

Electronic skin (e-skin) presents a network of mechanically flexible sensors that can conformally wrap irregular surfaces and spatially map and quantify various stimuli. Previous works on e-skin have focused on the optimization of pressure sensors interfaced with an electronic readout, whereas user interfaces based on a human-readable output were not explored. Here, we report the first user-interactive e-skin that not only spatially maps the applied pressure but also provides an instantaneous visual response through a built-in active-matrix organic light-emitting diode display with red, green and blue pixels. In this system, organic light-emitting diodes (OLEDs) are turned on locally where the surface is touched, and the intensity of the emitted light quantifies the magnitude of the applied pressure. This work represents a system-on-plastic demonstration where three distinct electronic components--thin-film transistor, pressure sensor and OLED arrays--are monolithically integrated over large areas on a single plastic substrate. The reported e-skin may find a wide range of applications in interactive input/control devices, smart wallpapers, robotics and medical/health monitoring devices.

In vivo imaging of neural reactive plasticity after laser axotomy in cerebellar cortex

NASA Astrophysics Data System (ADS)

Allegra Mascaro, A. L.; Sacconi, L.; Maco, B.; Knott, G. W.; Pavone, F. S.

2014-03-01

Multi-photon imaging provides valuable insights into the continuous reshaping of neuronal connectivity in live brain. We previously showed that single neuron or even single spine ablation can be achieved by laser-mediated dissection. Furthermore, single axonal branches can be dissected avoiding collateral damage to the adjacent dendrite and the formation of a persistent glial scar. Here, we describe the procedure to address the structural plasticity of cerebellar climbing fibers by combining two-photon in vivo imaging with laser axotomy in a mouse model. This method is a powerful tool to study the basic mechanisms of axonal rewiring after single branch axotomy in vivo. In fact, despite the denervated area being very small, the injured axons consistently reshape the connectivity with surrounding neurons, as indicated by the increase in the turnover of synaptic boutons. In addition, time-lapse imaging reveals the sprouting of new branches from the injured axon. Newly formed branches with varicosities suggest the possible formation of synaptic contacts. Correlative light and electron microscopy revealed that the sprouted branch contains large numbers of vesicles, with varicosities in the close vicinity of Purkinje dendrites.

Marine Litter Distribution and Density in European Seas, from the Shelves to Deep Basins

PubMed Central

Pham, Christopher K.; Ramirez-Llodra, Eva; Alt, Claudia H. S.; Amaro, Teresa; Bergmann, Melanie; Canals, Miquel; Company, Joan B.; Davies, Jaime; Duineveld, Gerard; Galgani, François; Howell, Kerry L.; Huvenne, Veerle A. I.; Isidro, Eduardo; Jones, Daniel O. B.; Lastras, Galderic; Morato, Telmo; Gomes-Pereira, José Nuno; Purser, Autun; Stewart, Heather; Tojeira, Inês; Tubau, Xavier; Van Rooij, David; Tyler, Paul A.

2014-01-01

Anthropogenic litter is present in all marine habitats, from beaches to the most remote points in the oceans. On the seafloor, marine litter, particularly plastic, can accumulate in high densities with deleterious consequences for its inhabitants. Yet, because of the high cost involved with sampling the seafloor, no large-scale assessment of distribution patterns was available to date. Here, we present data on litter distribution and density collected during 588 video and trawl surveys across 32 sites in European waters. We found litter to be present in the deepest areas and at locations as remote from land as the Charlie-Gibbs Fracture Zone across the Mid-Atlantic Ridge. The highest litter density occurs in submarine canyons, whilst the lowest density can be found on continental shelves and on ocean ridges. Plastic was the most prevalent litter item found on the seafloor. Litter from fishing activities (derelict fishing lines and nets) was particularly common on seamounts, banks, mounds and ocean ridges. Our results highlight the extent of the problem and the need for action to prevent increasing accumulation of litter in marine environments. PMID:24788771

Extremely flexible nanoscale ultrathin body silicon integrated circuits on plastic.

PubMed

Shahrjerdi, Davood; Bedell, Stephen W

2013-01-09

In recent years, flexible devices based on nanoscale materials and structures have begun to emerge, exploiting semiconductor nanowires, graphene, and carbon nanotubes. This is primarily to circumvent the existing shortcomings of the conventional flexible electronics based on organic and amorphous semiconductors. The aim of this new class of flexible nanoelectronics is to attain high-performance devices with increased packing density. However, highly integrated flexible circuits with nanoscale transistors have not yet been demonstrated. Here, we show nanoscale flexible circuits on 60 Å thick silicon, including functional ring oscillators and memory cells. The 100-stage ring oscillators exhibit the stage delay of ~16 ps at a power supply voltage of 0.9 V, the best reported for any flexible circuits to date. The mechanical flexibility is achieved by employing the controlled spalling technology, enabling the large-area transfer of the ultrathin body silicon devices to a plastic substrate at room temperature. These results provide a simple and cost-effective pathway to enable ultralight flexible nanoelectronics with unprecedented level of system complexity based on mainstream silicon technology.

The Arctic Ocean as a dead end for floating plastics in the North Atlantic branch of the Thermohaline Circulation

PubMed Central

Cózar, Andrés; Martí, Elisa; Duarte, Carlos M.; García-de-Lomas, Juan; van Sebille, Erik; Ballatore, Thomas J.; Eguíluz, Victor M.; González-Gordillo, J. Ignacio; Pedrotti, Maria L.; Echevarría, Fidel; Troublè, Romain; Irigoien, Xabier

2017-01-01

The subtropical ocean gyres are recognized as great marine accummulation zones of floating plastic debris; however, the possibility of plastic accumulation at polar latitudes has been overlooked because of the lack of nearby pollution sources. In the present study, the Arctic Ocean was extensively sampled for floating plastic debris from the Tara Oceans circumpolar expedition. Although plastic debris was scarce or absent in most of the Arctic waters, it reached high concentrations (hundreds of thousands of pieces per square kilometer) in the northernmost and easternmost areas of the Greenland and Barents seas. The fragmentation and typology of the plastic suggested an abundant presence of aged debris that originated from distant sources. This hypothesis was corroborated by the relatively high ratios of marine surface plastic to local pollution sources. Surface circulation models and field data showed that the poleward branch of the Thermohaline Circulation transfers floating debris from the North Atlantic to the Greenland and Barents seas, which would be a dead end for this plastic conveyor belt. Given the limited surface transport of the plastic that accumulated here and the mechanisms acting for the downward transport, the seafloor beneath this Arctic sector is hypothesized as an important sink of plastic debris. PMID:28439534

The Arctic Ocean as a dead end for floating plastics in the North Atlantic branch of the Thermohaline Circulation.

PubMed

Cózar, Andrés; Martí, Elisa; Duarte, Carlos M; García-de-Lomas, Juan; van Sebille, Erik; Ballatore, Thomas J; Eguíluz, Victor M; González-Gordillo, J Ignacio; Pedrotti, Maria L; Echevarría, Fidel; Troublè, Romain; Irigoien, Xabier

2017-04-01

The subtropical ocean gyres are recognized as great marine accummulation zones of floating plastic debris; however, the possibility of plastic accumulation at polar latitudes has been overlooked because of the lack of nearby pollution sources. In the present study, the Arctic Ocean was extensively sampled for floating plastic debris from the Tara Oceans circumpolar expedition. Although plastic debris was scarce or absent in most of the Arctic waters, it reached high concentrations (hundreds of thousands of pieces per square kilometer) in the northernmost and easternmost areas of the Greenland and Barents seas. The fragmentation and typology of the plastic suggested an abundant presence of aged debris that originated from distant sources. This hypothesis was corroborated by the relatively high ratios of marine surface plastic to local pollution sources. Surface circulation models and field data showed that the poleward branch of the Thermohaline Circulation transfers floating debris from the North Atlantic to the Greenland and Barents seas, which would be a dead end for this plastic conveyor belt. Given the limited surface transport of the plastic that accumulated here and the mechanisms acting for the downward transport, the seafloor beneath this Arctic sector is hypothesized as an important sink of plastic debris.

Co-pyrolysis of swine manure with agricultural plastic waste: laboratory-scale study.

PubMed

Ro, Kyoung S; Hunt, Patrick G; Jackson, Michael A; Compton, David L; Yates, Scott R; Cantrell, Keri; Chang, SeChin

2014-08-01

Manure-derived biochar is the solid product resulting from pyrolysis of animal manures. It has considerable potential both to improve soil quality with high levels of nutrients and to reduce contaminants in water and soil. However, the combustible gas produced from manure pyrolysis generally does not provide enough energy to sustain the pyrolysis process. Supplementing this process may be achieved with spent agricultural plastic films; these feedstocks have large amounts of available energy. Plastic films are often used in soil fumigation. They are usually disposed in landfills, which is wasteful, expensive, and environmentally unsustainable. The objective of this work was to investigate both the energetics of co-pyrolyzing swine solids with spent plastic mulch films (SPM) and the characteristics of its gas, liquid, and solid byproducts. The heating value of the product gas from co-pyrolysis was found to be much higher than that of natural gas; furthermore, the gas had no detectable toxic fumigants. Energetically, sustaining pyrolysis of the swine solids through the energy of the product gas could be achieved by co-pyrolyzing dewatered swine solids (25%m/m) with just 10% SPM. If more than 10% SPM is used, the co-pyrolysis would generate surplus energy which could be used for power generation. Biochars produced from co-pyrolyzing SPM and swine solid were similar to swine solid alone based on the surface area and the (1)H NMR spectra. The results of this study demonstrated the potential of using pyrolysis technology to manage two prominent agricultural waste streams (SPM and swine solids) while producing value-added biochar and a power source that could be used for local farm operations. Published by Elsevier Ltd.

Modelling highly deformable metal extrusion using SPH

NASA Astrophysics Data System (ADS)

Prakash, Mahesh; Cleary, Paul W.

2015-05-01

Computational modelling is often used to reduce trial extrusions through accurate defect prediction. Traditionally, metal extrusion is modelled using mesh based finite element methods. However, large plastic deformations can lead to heavy re-meshing and numerical diffusion. Here we use the mesh-less smoothed particle hydrodynamics method since it allows simulation of large deformations without re-meshing and the tracking of history dependent properties such as plastic strain making it suitable for defect prediction. The variation in plastic strain and deformation for aluminium alloy in a cylindrical 3D geometry with extrusion ratio and die angle is evaluated. The extrusion process is found to have three distinct phases consisting of an initial sharp rise in extrusion force, a steady phase requiring constant force and terminating in a sharp decline in force as metal is completely extruded. Deformation and plastic strain increased significantly with extrusion ratio but only moderately with die angle. Extrusion force increased by 150 % as the extrusion ratio increased from 2:1 to 4:1 but had only a marginal change with die angle. A low strain zone in the centre of the extruded product was found to be a function of extrusion ratio but was persistent and did not vary with die angle. Simulation of a complex 3D building industry component showed large variations in plastic strain along the length of the product at two scales. These were due to change in metal behaviour as extrusion progressed from phase 1 to phase 2. A stagnation zone at the back of the die was predicted that could lead to the "funnel" or "pipe" defect.

AUDITORY ASSOCIATIVE MEMORY AND REPRESENTATIONAL PLASTICITY IN THE PRIMARY AUDITORY CORTEX

PubMed Central

Weinberger, Norman M.

2009-01-01

Historically, the primary auditory cortex has been largely ignored as a substrate of auditory memory, perhaps because studies of associative learning could not reveal the plasticity of receptive fields (RFs). The use of a unified experimental design, in which RFs are obtained before and after standard training (e.g., classical and instrumental conditioning) revealed associative representational plasticity, characterized by facilitation of responses to tonal conditioned stimuli (CSs) at the expense of other frequencies, producing CS-specific tuning shifts. Associative representational plasticity (ARP) possesses the major attributes of associative memory: it is highly specific, discriminative, rapidly acquired, consolidates over hours and days and can be retained indefinitely. The nucleus basalis cholinergic system is sufficient both for the induction of ARP and for the induction of specific auditory memory, including control of the amount of remembered acoustic details. Extant controversies regarding the form, function and neural substrates of ARP appear largely to reflect different assumptions, which are explicitly discussed. The view that the forms of plasticity are task-dependent is supported by ongoing studies in which auditory learning involves CS-specific decreases in threshold or bandwidth without affecting frequency tuning. Future research needs to focus on the factors that determine ARP and their functions in hearing and in auditory memory. PMID:17344002

A crystal plasticity model incorporating the effects of precipitates in superalloys: Application to tensile, compressive, and cyclic deformation of Inconel 718

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ghorbanpour, Saeede; Zecevic, Milovan; Kumar, Anil

An elasto-plastic polycrystal plasticity model is developed and applied to an Inconel 718 (IN718) superalloy that was produced by additive manufacturing (AM). The model takes into account the contributions of solid solution, precipitates shearing, and grain size and shape effects into the initial slip resistance. Non-Schmid effects and backstress are also included in the crystal plasticity model for activating slip. The hardening law for the critical resolved shear stress is based on the evolution of dislocation density. In using the same set of material and physical parameters, the model is compared against a suite of compression, tension, and large-strain cyclicmore » mechanical test data applied in different AM build directions. We demonstrate that the model is capable of predicting the particularities of both monotonic and cyclic deformation to large strains of the alloy, including decreasing hardening rate during monotonic loading, the non-linear unloading upon the load reversal, the Bauschinger effect, the hardening rate change during loading in the reverse direction as well as plastic anisotropy and the concomitant microstructure evolution. It is anticipated that the general model developed here can be applied to other multiphase alloys containing precipitates.« less

A crystal plasticity model incorporating the effects of precipitates in superalloys: Application to tensile, compressive, and cyclic deformation of Inconel 718

DOE PAGES

Ghorbanpour, Saeede; Zecevic, Milovan; Kumar, Anil; ...

2017-09-14

An elasto-plastic polycrystal plasticity model is developed and applied to an Inconel 718 (IN718) superalloy that was produced by additive manufacturing (AM). The model takes into account the contributions of solid solution, precipitates shearing, and grain size and shape effects into the initial slip resistance. Non-Schmid effects and backstress are also included in the crystal plasticity model for activating slip. The hardening law for the critical resolved shear stress is based on the evolution of dislocation density. In using the same set of material and physical parameters, the model is compared against a suite of compression, tension, and large-strain cyclicmore » mechanical test data applied in different AM build directions. We demonstrate that the model is capable of predicting the particularities of both monotonic and cyclic deformation to large strains of the alloy, including decreasing hardening rate during monotonic loading, the non-linear unloading upon the load reversal, the Bauschinger effect, the hardening rate change during loading in the reverse direction as well as plastic anisotropy and the concomitant microstructure evolution. It is anticipated that the general model developed here can be applied to other multiphase alloys containing precipitates.« less

Pyrolysis-catalysis of waste plastic using a nickel-stainless-steel mesh catalyst for high-value carbon products.

PubMed

Zhang, Yeshui; Nahil, Mohamad A; Wu, Chunfei; Williams, Paul T

2017-11-01

A stainless-steel mesh loaded with nickel catalyst was produced and used for the pyrolysis-catalysis of waste high-density polyethylene with the aim of producing high-value carbon products, including carbon nanotubes (CNTs). The catalysis temperature and plastic-to-catalyst ratio were investigated to determine the influence on the formation of different types of carbon deposited on the nickel-stainless-steel mesh catalyst. Increasing temperature from 700 to 900°C resulted in an increase in the carbon deposited on the nickel-loaded stainless-steel mesh catalyst from 32.5 to 38.0 wt%. The increase in sample-to-catalyst ratio reduced the amount of carbon deposited on the mesh catalyst in terms of g carbon g -1 plastic. The carbons were found to be largely composed of filamentous carbons, with negligible disordered (amorphous) carbons. Transmission electron microscopy analysis of the filamentous carbons revealed them to be composed of a large proportion (estimated at ∼40%) multi-walled carbon nanotubes (MWCNTs). The optimum process conditions for CNT production, in terms of yield and graphitic nature, determined by Raman spectroscopy, was catalysis temperature of 800°C and plastic-to-catalyst ratio of 1:2, where a mass of 334 mg of filamentous/MWCNTs g -1 plastic was produced.

Geometric correction methods for Timepix based large area detectors

NASA Astrophysics Data System (ADS)

Zemlicka, J.; Dudak, J.; Karch, J.; Krejci, F.

2017-01-01

X-ray micro radiography with the hybrid pixel detectors provides versatile tool for the object inspection in various fields of science. It has proven itself especially suitable for the samples with low intrinsic attenuation contrast (e.g. soft tissue in biology, plastics in material sciences, thin paint layers in cultural heritage, etc.). The limited size of single Medipix type detector (1.96 cm2) was recently overcome by the construction of large area detectors WidePIX assembled of Timepix chips equipped with edgeless silicon sensors. The largest already built device consists of 100 chips and provides fully sensitive area of 14.3 × 14.3 cm2 without any physical gaps between sensors. The pixel resolution of this device is 2560 × 2560 pixels (6.5 Mpix). The unique modular detector layout requires special processing of acquired data to avoid occurring image distortions. It is necessary to use several geometric compensations after standard corrections methods typical for this type of pixel detectors (i.e. flat-field, beam hardening correction). The proposed geometric compensations cover both concept features and particular detector assembly misalignment of individual chip rows of large area detectors based on Timepix assemblies. The former deals with larger border pixels in individual edgeless sensors and their behaviour while the latter grapple with shifts, tilts and steps between detector rows. The real position of all pixels is defined in Cartesian coordinate system and together with non-binary reliability mask it is used for the final image interpolation. The results of geometric corrections for test wire phantoms and paleo botanic material are presented in this article.

Plastics in soil: Analytical methods and possible sources.

PubMed

Bläsing, Melanie; Amelung, Wulf

2018-01-15

At least 300 Mio t of plastic are produced annually, from which large parts end up in the environment, where it persists over decades, harms biota and enters the food chain. Yet, almost nothing is known about plastic pollution of soil; hence, the aims of this work are to review current knowledge on i) available methods for the quantification and identification of plastic in soil, ii) the quantity and possible input pathways of plastic into soil, (including first preliminary screening of plastic in compost), and iii) its fate in soil. Methods for plastic analyses in sediments can potentially be adjusted for application to soil; yet, the applicability of these methods for soil needs to be tested. Consequently, the current data base on soil pollution with plastic is still poor. Soils may receive plastic inputs via plastic mulching or the application of plastic containing soil amendments. In compost up to 2.38-1200mg plastic kg -1 have been found so far; the plastic concentration of sewage sludge varies between 1000 and 24,000 plastic items kg -1 . Also irrigation with untreated and treated wastewater (1000-627,000 and 0-125,000 plastic items m -3 , respectively) as well as flooding with lake water (0.82-4.42 plastic items m -3 ) or river water (0-13,751 items km -2 ) can provide major input pathways for plastic into soil. Additional sources comprise littering along roads and trails, illegal waste dumping, road runoff as well as atmospheric input. With these input pathways, plastic concentrations in soil might reach the per mill range of soil organic carbon. Most of plastic (especially >1μm) will presumably be retained in soil, where it persists for decades or longer. Accordingly, further research on the prevalence and fate of such synthetic polymers in soils is urgently warranted. Copyright © 2017 Elsevier B.V. All rights reserved.

Industrial radiography with cosmic-ray muons: A progress report

NASA Astrophysics Data System (ADS)

Gilboy, W. B.; Jenneson, P. M.; Simons, S. J. R.; Stanley, S. J.; Rhodes, D.

2007-09-01

Cosmic-ray produced muons arrive at the surface of the earth with enormous energies ranging up to 1012 GeV. There have been sporadic attempts to exploit their extreme penetration through matter to probe the internal structures of very large objects, including an Egyptian pyramid and a volcano but their very low intensity per unit area ( ≈1 cm-2 per min) generally restricts the practicably attainable spatial resolution to large dimensions. Nevertheless the more intense low energy region of the muon spectrum has recently been shown to be capable of detecting high-Z objects with dimensions of the order of 10 cm hidden inside large transport containers in measurement times of minutes. These various developments have encouraged further studies of potential industrial uses of cosmic-ray muons in industrial applications. In order to gain maximum benefit from the low muon flux large area detectors are required and plastic scintillators offer useful advantages in size, cost and simplicity. Scintillator slabs up to 1 m2 square and 76.2 mm thick are undergoing testing for applications in the nuclear industry. The most direct approach employs photomultiplier tubes at each corner to measure the relative sizes of muon induced pulses to determine the location of each muon track passing through the scintillator. The performance of this technique is reported and its imaging potential is assessed.

ZIP2DL: An Elastic-Plastic, Large-Rotation Finite-Element Stress Analysis and Crack-Growth Simulation Program

NASA Technical Reports Server (NTRS)

Deng, Xiaomin; Newman, James C., Jr.

1997-01-01

ZIP2DL is a two-dimensional, elastic-plastic finte element program for stress analysis and crack growth simulations, developed for the NASA Langley Research Center. It has many of the salient features of the ZIP2D program. For example, ZIP2DL contains five material models (linearly elastic, elastic-perfectly plastic, power-law hardening, linear hardening, and multi-linear hardening models), and it can simulate mixed-mode crack growth for prescribed crack growth paths under plane stress, plane strain and mixed state of stress conditions. Further, as an extension of ZIP2D, it also includes a number of new capabilities. The large-deformation kinematics in ZIP2DL will allow it to handle elastic problems with large strains and large rotations, and elastic-plastic problems with small strains and large rotations. Loading conditions in terms of surface traction, concentrated load, and nodal displacement can be applied with a default linear time dependence or they can be programmed according to a user-defined time dependence through a user subroutine. The restart capability of ZIP2DL will make it possible to stop the execution of the program at any time, analyze the results and/or modify execution options and resume and continue the execution of the program. This report includes three sectons: a theoretical manual section, a user manual section, and an example manual secton. In the theoretical secton, the mathematics behind the various aspects of the program are concisely outlined. In the user manual section, a line-by-line explanation of the input data is given. In the example manual secton, three types of examples are presented to demonstrate the accuracy and illustrate the use of this program.

Characterization of Different Types of Excitability in Large Somatosensory Neurons and Its Plastic Changes in Pathological Pain States

PubMed Central

Xie, Rou-Gang; Chu, Wen-Guang; Hu, San-Jue; Luo, Ceng

2018-01-01

Sensory neuron types have been distinguished by distinct morphological and transcriptional characteristics. Excitability is the most fundamental functional feature of neurons. Mathematical models described by Hodgkin have revealed three types of neuronal excitability based on the relationship between firing frequency and applied current intensity. However, whether natural sensory neurons display different functional characteristics in terms of excitability and whether this excitability type undergoes plastic changes under pathological pain states have remained elusive. Here, by utilizing whole-cell patch clamp recordings, behavioral and pharmacological assays, we demonstrated that large dorsal root ganglion (DRG) neurons can be classified into three classes and four subclasses based on their excitability patterns, which is similar to mathematical models raised by Hodgkin. Analysis of hyperpolarization-activated cation current (Ih) revealed different magnitude of Ih in different excitability types of large DRG neurons, with higher Ih in Class 2-1 than that in Class 1, 2-2 and 3. This indicates a crucial role of Ih in the determination of excitability type of large DRG neurons. More importantly, this pattern of excitability displays plastic changes and transition under pathological pain states caused by peripheral nerve injury. This study sheds new light on the functional characteristics of large DRG neurons and extends functional classification of large DRG neurons by integration of transcriptomic and morphological characteristics. PMID:29303989

Characteristics of organic matter in PM2.5 from an e-waste dismantling area in Taizhou, China.

PubMed

Gu, Zeping; Feng, Jialiang; Han, Wenliang; Wu, Minghong; Fu, Jiamo; Sheng, Guoying

2010-08-01

Solvent extractable organic compounds in PM(2.5) samples collected in Taizhou, a city famous for its electrical and electronic waste (e-waste) recycling industry in Zhejiang province of China, were analyzed to identify the main emission sources based on molecular markers. Two types of plastics which were most frequently contained in the e-wastes, wires/cables and plastic blocks, were burned in the lab and the particles emitted analyzed. The concentrations of PAHs and phthalate esters at the e-waste dismantling area during our sampling periods were about two times of that at the reference urban site, indicating the high pollution level there. The high concentrations of quaterphenyl found at the dismantling area indicated that burning of plastics or polymers was an important emission source of the PAHs in the fine particles. The diagnostic analysis based on the compositions of alkanes, hopanes and other molecular markers showed that engine exhaust, biomass burning and kitchen emissions were also important emission sources at the e-waste dismantling area. Our results suggested that more effort should be paid to control the correlative emission sources such as transportation and kitchen to achieve better air quality at the e-waste dismantling area besides regulating the recycling activities. Copyright 2010 Elsevier Ltd. All rights reserved.

Public perception of Plastic Surgery.

PubMed

de Blacam, Catherine; Kilmartin, Darren; Mc Dermott, Clodagh; Kelly, Jack

2015-02-01

Public perception of Plastic Surgery is strongly influenced by the media and may not reflect the broad scope of work within the speciality. The aim of this study was to provide an assessment of the general public's perception of plastic surgical practice and to report the perceived importance of Plastic Surgery relative to other specialities working within a large tertiary referral centre. 899 members of the public who attended our Emergency Department completed a questionnaire where they matched eight surgical specialities with 30 operative procedures and ranked the importance of 30 different hospital specialities using a Likert scale. The majority of respondents correctly identified plastic surgeons as performing each of the cosmetic procedures listed (abdominoplasty 63.7%; breast augmentation 59.1%; facelift 61.35%; liposuction 59.7%). Plastic Surgery was identified as the primary speciality involved in breast reconstruction (49.3%) and burns surgery (43.0%). There was poor understanding of the role of plastic surgeons in hand surgery, with only 4.7% of respondents attributing tendon repair to plastic surgeons. Plastic Surgery ranked lowest of 30 specialities in terms of importance in providing care for patients within the hospital. Plastic Surgery is often misunderstood within the wider community and misconceptions reflect the influence of the media in highlighting certain aspects of the speciality. It behoves our professional organisations to highlight the importance of Plastic and Reconstructive Surgery within major tertiary referral centres. Copyright © 2014 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved.

Tribo-charging properties of waste plastic granules in process of tribo-electrostatic separation.

PubMed

Li, Jia; Wu, Guiqing; Xu, Zhenming

2015-01-01

Plastic products can be found everywhere in people's daily life. With the consistent growth of plastic consumption, more and more plastic waste is generated. Considering the stable chemical and physics characteristics of plastic, regular waste management methods are not suitable for recycling economic strategy of each government, which has become a serious environmental problem. Recycling plastic waste is considered to be the best way to treat it, because it cannot only deduce the waste but also save the energy to produce new virgin plastic. Tribo-electrostatic separation is strongly recommended for plastic separation as it can preserve the original properties of plastic and has little additional pollution. In this study, plastic granules are generated by crushing plastic waste in waste electric and electronic equipment. The tribo-charging properties of plastic waste were studied by vibrating tribo-charging and cyclone tribo-charging. The triboelectric series obtained by vibrating was: (-)-PE-PS-PC-PVC-ABS-PP-(+), while the triboelectric series obtained by cyclone was (-)-PE-PS-PC-PVC-ABS-PP-(+). Further, the cyclone charging was more effective and stable than vibrating charging. The impact factors experiments showed that small particle size was better changed than large ones and were more suitable recycled by tribo-electrostatic separation. High relative humidity was identified as impede charging effect. The results of this study will help defining the operating parameters of subsequent separator. Copyright © 2014 Elsevier Ltd. All rights reserved.

Stability of surface plastic flow in large strain deformation of metals

NASA Astrophysics Data System (ADS)

Viswanathan, Koushik; Udapa, Anirduh; Sagapuram, Dinakar; Mann, James; Chandrasekar, Srinivasan

We examine large-strain unconstrained simple shear deformation in metals using a model two-dimensional cutting system and high-speed in situ imaging. The nature of the deformation mode is shown to be a function of the initial microstructure state of the metal and the deformation geometry. For annealed metals, which exhibit large ductility and strain hardening capacity, the commonly assumed laminar flow mode is inherently unstable. Instead, the imposed shear is accommodated by a highly rotational flow-sinuous flow-with vortex-like components and large-amplitude folding on the mesoscale. Sinuous flow is triggered by a plastic instability on the material surface ahead of the primary region of shear. On the other hand, when the material is extensively strain-hardened prior to shear, laminar flow again becomes unstable giving way to shear banding. The existence of these flow modes is established by stability analysis of laminar flow. The role of the initial microstructure state in determining the change in stability from laminar to sinuous / shear-banded flows in metals is elucidated. The implications for cutting, forming and wear processes for metals, and to surface plasticity phenomena such as mechanochemical Rehbinder effects are discussed.

49 CFR 178.925 - Standards for rigid plastic Large Packagings.

Code of Federal Regulations, 2010 CFR

2010-10-01

... manufacture of the tested design type, retesting may be omitted if changes in the carbon black content, the... or chemical properties of the material of construction. (3) No used material other than production residues or regrind from the same manufacturing process may be used in the manufacture of rigid plastic...

Understanding and Overcoming Implicit Gender Bias in Plastic Surgery.

PubMed

Phillips, Nicole A; Tannan, Shruti C; Kalliainen, Loree K

2016-11-01

Although explicit sex-based discrimination has largely been deemed unacceptable in professional settings, implicit gender bias persists and results in a significant lack of parity in plastic surgery and beyond. Implicit gender bias is the result of a complex interplay of cultural and societal expectations, learned behaviors, and standardized associations. As such, both male and female surgeons are subject to its influence. A review of the literature was conducted, examining theories of gender bias, current manifestations of gender bias in plastic surgery and other fields, and interventions designed to address gender bias. Multiple studies demonstrate persistent gender bias that impacts female physicians at all levels of training. Several institutions have enacted successful interventions to identify and address gender bias. Explicit gender bias has largely disappeared, yet unconscious or implicit gender bias persists. A wide-scale commitment to addressing implicit gender bias in plastic surgery is necessary and overdue. Recommendations include immediate actions that can be undertaken on an individual basis, and changes that should be implemented at a national and international level by leaders in the field.

Abnormal cortical synaptic plasticity in primary motor area in progressive supranuclear palsy.

PubMed

Conte, Antonella; Belvisi, Daniele; Bologna, Matteo; Ottaviani, Donatella; Fabbrini, Giovanni; Colosimo, Carlo; Williams, David R; Berardelli, Alfredo

2012-03-01

No study has yet investigated whether cortical plasticity in primary motor area (M1) is abnormal in patients with progressive supranuclear palsy (PSP). We studied M1 plasticity in 15 PSP patients and 15 age-matched healthy subjects. We used intermittent theta-burst stimulation (iTBS) to investigate long-term potentiation (LTP) and continuous TBS (cTBS) to investigate long-term depression (LTD)-like cortical plasticity in M1. Ten patients underwent iTBS again 1 year later. We also investigated short-interval intracortical inhibition (SICI) and intracortical facilitation (ICF) in M1 with paired-pulse transcranial magnetic stimulation, tested H reflex from upper limb flexor muscles before and after iTBS, and measured motor evoked potential (MEP) input-output (I/O) curves before and after iTBS. iTBS elicited a significantly larger MEP facilitation after iTBS in patients than in healthy subjects. Whereas in healthy subjects, cTBS inhibited MEP, in patients it significantly facilitated MEPs. In patients, SICI was reduced, whereas ICF was normal. H reflex size remained unchanged after iTBS. Patients had steeper MEP I/O slopes than healthy subjects at baseline and became even more steeper after iTBS only in patients. The iTBS-induced abnormal MEP facilitation in PSP persisted at 1-year follow-up. In conclusion, patients with PSP have abnormal M1 LTP/LTD-like plasticity. The enhanced LTP-like cortical synaptic plasticity parallels disease progression.

Military Handbook: Electrostatic Discharge Control Handbook for Protection of Electrical and Electronic Parts, Assemblies and Equipment (Excluding Electrically Initiated Explosive Devices (Metric)

DTIC Science & Technology

1994-07-31

everything that is received in ESD protective packaging materials treated as ESDS? YES/NO 40.1.13 Is the use of personal hygiene products , food, drinks...Does the training explain why food, drinks, smoking, personal hygiene products or common plastics are not to be used in ESD protective work areas? YES...trays? YES/NO 40.5.13 Are drinking, eating, smoking, the use of personal hygiene products and common plastics prohibited in the ESD protected work area

Brain plasticity in the adult: modulation of function in amblyopia with rTMS.

PubMed

Thompson, Benjamin; Mansouri, Behzad; Koski, Lisa; Hess, Robert F

2008-07-22

Amblyopia is a cortically based visual disorder caused by disruption of vision during a critical early developmental period. It is often thought to be a largely intractable problem in adult patients because of a lack of neuronal plasticity after this critical period [1]; however, recent advances have suggested that plasticity is still present in the adult amblyopic visual cortex [2-6]. Here, we present data showing that repetitive transcranial magnetic stimulation (rTMS) of the visual cortex can temporarily improve contrast sensitivity in the amblyopic visual cortex. The results indicate continued plasticity of the amblyopic visual system in adulthood and open the way for a potential new therapeutic approach to the treatment of amblyopia.

E-Cigarettes and Potential Implications for Plastic Surgery.

PubMed

Taub, Peter J; Matarasso, Alan

2016-12-01

The use of tobacco-based products, most notably cigarettes, is related directly to wound healing problems and poorer outcomes in plastic surgery. Current abstracts have highlighted the potential complications from nicotine, specifically following plastic surgery in patients who choose to smoke. Recently, products that use electricity to vaporize liquid nitrogen have been gaining popularity. New rules were recently proposed that would give the federal government authority over electronic cigarettes. However, the health-related issues surrounding e-cigarettes are still largely unknown or misunderstood. These issues also extend to their impact on surgical procedures, notably their effect on plastic surgical procedures that rely heavily on the vascularity of either the host wound bed or the replacement tissue.

Consumer hazards of plastics.

PubMed Central

Wiberg, G S

1976-01-01

The modern consumer is exposed to a wide variety of plastic and rubber products in his day to day life: at home, work, school, shopping, recreation and play, and transport. A large variety of toxic sequellae have resulted from untoward exposures by many different routes: oral, dermal, inhalation, and parenteral. Toxic change may result from the plastic itself, migration of unbound components and additives, chemical decomposition or toxic pyrolysis products. The type of damage may involve acute poisoning, chronic organ damage, reproductive disorders, and carcinogenic, mutagenic and teratogenic episodes. Typical examples for all routes are cited along with the activites of Canadian regulatory agencies to reduce both the incidence and severity of plastic-induced disease. PMID:1026409

A study of elastic and plastic stress concentration factors due to notches and fillets in flat plates

NASA Technical Reports Server (NTRS)

Hardrath, Herbert F; Ohman, Lachlan

1953-01-01

Six large 24s-t3 aluminum-alloy-sheet specimens containing various notches or fillets were tested in tension to determine their stress concentration factors in both the elastic and plastic ranges. The elastic stress concentration factors were found to be slightly higher than those calculated by Neuber's method and those obtained photoelastically by Frocht. The results showed further that the stress concentration factor decreases as strains at the discontinuity enter the plastic range. A generalization of Stowell's relation for the plastic stress concentration factor at a circular hole in an infinite plate was applied to the specimen shapes tested and gave good agreement with test results.

Functional connectivity of visual cortex in the blind follows retinotopic organization principles.

PubMed

Striem-Amit, Ella; Ovadia-Caro, Smadar; Caramazza, Alfonso; Margulies, Daniel S; Villringer, Arno; Amedi, Amir

2015-06-01

Is visual input during critical periods of development crucial for the emergence of the fundamental topographical mapping of the visual cortex? And would this structure be retained throughout life-long blindness or would it fade as a result of plastic, use-based reorganization? We used functional connectivity magnetic resonance imaging based on intrinsic blood oxygen level-dependent fluctuations to investigate whether significant traces of topographical mapping of the visual scene in the form of retinotopic organization, could be found in congenitally blind adults. A group of 11 fully and congenitally blind subjects and 18 sighted controls were studied. The blind demonstrated an intact functional connectivity network structural organization of the three main retinotopic mapping axes: eccentricity (centre-periphery), laterality (left-right), and elevation (upper-lower) throughout the retinotopic cortex extending to high-level ventral and dorsal streams, including characteristic eccentricity biases in face- and house-selective areas. Functional connectivity-based topographic organization in the visual cortex was indistinguishable from the normally sighted retinotopic functional connectivity structure as indicated by clustering analysis, and was found even in participants who did not have a typical retinal development in utero (microphthalmics). While the internal structural organization of the visual cortex was strikingly similar, the blind exhibited profound differences in functional connectivity to other (non-visual) brain regions as compared to the sighted, which were specific to portions of V1. Central V1 was more connected to language areas but peripheral V1 to spatial attention and control networks. These findings suggest that current accounts of critical periods and experience-dependent development should be revisited even for primary sensory areas, in that the connectivity basis for visual cortex large-scale topographical organization can develop without any visual experience and be retained through life-long experience-dependent plasticity. Furthermore, retinotopic divisions of labour, such as that between the visual cortex regions normally representing the fovea and periphery, also form the basis for topographically-unique plastic changes in the blind. © The Author (2015). Published by Oxford University Press on behalf of the Guarantors of Brain.

Industrial Arts 7-9. Manufacturing: Metalwork, Plastics, Woodwork, Manufacturing.

ERIC Educational Resources Information Center

Manitoba Dept. of Education, Winnipeg. Div. of Vocational Education.

This curriculum guide provides materials for the industrial arts (grades 7-9) subject cluster of manufacturing. This subject cluster has four areas of study: metalwork, plastics, woodwork, and manufacturing. Introductory materials include an overview of the industrial arts curriculum in its entirety, a listing of program objectives for each of the…

Extraordinary adaptive plasticity of Colorado potato beetle: “Ten-striped spearman” in the era of biotechnological warfare

USDA-ARS?s Scientific Manuscript database

Expanding from remote areas of Mexico to a worldwide scale, the ten-striped insect, the Colorado potato beetle (CPB, Leptinotarsa decemlineata Say), has risen from being an innocuous beetle to a prominent global pest. A diverse life cycle, phenotypic plasticity, adaptation to adverse conditions, and...

36 CFR 1254.10 - For how long and where is my researcher identification card valid?

Code of Federal Regulations, 2010 CFR

2010-07-01

... facilities in the Washington, DC, area and other NARA facilities that issue and use plastic researcher identification cards as part of their security systems, we issue a plastic card to replace the paper card issued... ARCHIVES AND RECORDS ADMINISTRATION PUBLIC AVAILABILITY AND USE USING RECORDS AND DONATED HISTORICAL...

Scotblood 2007: Tackling local and global issues in transfusion medicine - donor recruitment, effective use of blood, stem cell plasticity, and vCJD.

PubMed

Bessos, Hagop; Fraser, Robin; Seghatchian, Jerard

2008-02-01

This commentary briefly highlights some of the local and the global contemporary issues affecting transfusion medicine worldwide. The main areas of focus addressed this year were: donor recruitment, stem cell plasticity, the effective use of blood, and vCJD.

Microplastics, Macroproblems?

NASA Astrophysics Data System (ADS)

Greene, V.; Adams, S.; Adams, A.

2017-12-01

Microplastics and plastics have polluted water all over the world including the Great Lakes. Microplastics can result from plastics that have broken up into smaller pieces or they can be purposely made and used in a variety of products. The size of a microplastic is less than 5 mm in length. These plastics can cause problems because they are non-biodegradable. Animals that have ingested these plastics have had reduced reproductive rates, health problems, and have even died from malnutrition. Our goal is to learn more about this issue. To do this, we will take water samples from different areas along the Gulf of Mexico and inland bays along the Florida coastline and compare the amount of microplastics found in each area. To analyze our samples we will vacuum filter water samples using gridded filter paper. We will then organize these samples by size and color. The control for our experiment will be filtered water. Our hypothesis is that Gulf of Mexico water samples will have more microplastics than the Bay water samples. We want to research this topic because microplastics can harm our ecosystems by affecting the health of marine animals.

Plasticity of brain wave network interactions and evolution across physiologic states

PubMed Central

Liu, Kang K. L.; Bartsch, Ronny P.; Lin, Aijing; Mantegna, Rosario N.; Ivanov, Plamen Ch.

2015-01-01

Neural plasticity transcends a range of spatio-temporal scales and serves as the basis of various brain activities and physiologic functions. At the microscopic level, it enables the emergence of brain waves with complex temporal dynamics. At the macroscopic level, presence and dominance of specific brain waves is associated with important brain functions. The role of neural plasticity at different levels in generating distinct brain rhythms and how brain rhythms communicate with each other across brain areas to generate physiologic states and functions remains not understood. Here we perform an empirical exploration of neural plasticity at the level of brain wave network interactions representing dynamical communications within and between different brain areas in the frequency domain. We introduce the concept of time delay stability (TDS) to quantify coordinated bursts in the activity of brain waves, and we employ a system-wide Network Physiology integrative approach to probe the network of coordinated brain wave activations and its evolution across physiologic states. We find an association between network structure and physiologic states. We uncover a hierarchical reorganization in the brain wave networks in response to changes in physiologic state, indicating new aspects of neural plasticity at the integrated level. Globally, we find that the entire brain network undergoes a pronounced transition from low connectivity in Deep Sleep and REM to high connectivity in Light Sleep and Wake. In contrast, we find that locally, different brain areas exhibit different network dynamics of brain wave interactions to achieve differentiation in function during different sleep stages. Moreover, our analyses indicate that plasticity also emerges in frequency-specific networks, which represent interactions across brain locations mediated through a specific frequency band. Comparing frequency-specific networks within the same physiologic state we find very different degree of network connectivity and link strength, while at the same time each frequency-specific network is characterized by a different signature pattern of sleep-stage stratification, reflecting a remarkable flexibility in response to change in physiologic state. These new aspects of neural plasticity demonstrate that in addition to dominant brain waves, the network of brain wave interactions is a previously unrecognized hallmark of physiologic state and function. PMID:26578891

Testing the adaptive plasticity of Iris pumila leaf traits to natural light conditions using phenotypic selection analysis

NASA Astrophysics Data System (ADS)

Tucić, Branka; Tomić, Vladimir; Avramov, Stevan; Pemac, Danijela

1998-12-01

A multivariate selection analysis has been used to test the adaptiveness of several Iris pumila leaf traits that display plasticity to natural light conditions. Siblings of a synthetic population comprising 31 families of two populations from contrasting light habitats were grown at an open dune site and in the understory of a Pinus nigra stand in order to score variation in phenotypic expression of six leaf traits: number of senescent leaves, number of live leaves, leaf length, leaf width, leaf angle, and specific leaf area. The ambient light conditions affected the values of all traits studied except for specific leaf area. In accordance to ecophysiological expectations for an adaptive response to light, both leaf length and width were significantly greater while the angle between sequential leaves was significantly smaller in the woodland understory than at the exposed dune site. The relationship between leaf traits and vegetative fitness (total leaf area) differed across light habitats as predicted by functional hypotheses. The standardized linear selection gradient ( β') for leaf length and width were positive in sign in both environments, but their magnitude for leaf length was higher in the shade than under full sunlight. Since plasticity of leaf length in the woodland shade has been recognized as adaptive, fitness cost of producing plastic change in leaf length was assessed. In both of the available methods used, the two-step and the multivariate regression procedures, a rather high negative association between the fitness value and the plasticity of leaf length was obtained, indicating a cost of plasticity. The selection gradient for leaf angle was weak and significant only in the woodland understory. Genetic correlations between trait expressions in contrasting light environments were negative in sign and low in magnitude, implying a significant genetic variation for plasticity in these leaf traits. Furthermore, leaf length and leaf width were found to be genetically positively coupled, which indicates that there is a potential for these two traits to evolve toward their optimal phenotypic values even faster than would be expected if they were genetically independent.

Optical Sensors Based on Plastic Fibers

PubMed Central

Bilro, Lúcia; Alberto, Nélia; Pinto, João L.; Nogueira, Rogério

2012-01-01

The recent advances of polymer technology allowed the introduction of plastic optical fiber in sensor design. The advantages of optical metrology with plastic optical fiber have attracted the attention of the scientific community, as they allow the development of low-cost or cost competitive systems compared with conventional technologies. In this paper, the current state of the art of plastic optical fiber technology will be reviewed, namely its main characteristics and sensing advantages. Several measurement techniques will be described, with a strong focus on interrogation approaches based on intensity variation in transmission and reflection. The potential applications involving structural health monitoring, medicine, environment and the biological and chemical area are also presented. PMID:23112707

A new bistable electroactive polymer for prolonged cycle lifetime of refreshable Braille displays

NASA Astrophysics Data System (ADS)

Ren, Zhi; Niu, Xiaofan; Chen, Dustin; Hu, Wei; Pei, Qibing

2014-03-01

ABSTRACT: Bistable electroactive polymers (BSEP) amalgamating electrically induced large-strain actuation and shape memory effect present a unique opportunity for refreshable Braille displays. A new BSEP material with long-chain crosslinkers to achieve prolonged cycle lifetime of refreshable Braille displays is reported here. The modulus of the BSEP material decreases by more than three orders of magnitude from a rigid, plastic state to a rubbery state when heated above the polymer's glass transition temperature. In its rubbery state, the polymer film can be electrically actuated to buckle convexly when a high voltage is applied across a circular active area. Modifying the concentration of long-chain crosslinkers in the polymer allows not only for fine-tuning of the polymer's glass transition temperature and elasticity in the rubbery state, but also enhancement of the actuation stability. For a raised height of 0.4 mm by a Braille dot with a 1.3 mm diameter, actuation can be repeated over 2000 cycles at 70°C in the rubbery state. The actuated dome shape can be fixed by cooling the polymer below the glass transition temperature. This refreshable rigid-to-rigid actuation simultaneously provides large-strain actuation and large force support. Devices capable of displaying Braille characters over a page-size area consisting of 324 Braille cells have been fabricated.

Monitoring of WEEE plastics in regards to brominated flame retardants using handheld XRF

DOE Office of Scientific and Technical Information (OSTI.GOV)

Aldrian, Alexia, E-mail: alexia.aldrian@unileoben.ac.at; Ledersteger, Alfred, E-mail: a.ledersteger@saubermacher.at; Pomberger, Roland, E-mail: roland.pomberger@unileoben.ac.at

Highlights: • Specification of an empirical factor for conversion from bromine to PBB and PBDE. • The handheld XRF device was validated for this particular application. • A very large number of over 4600 pieces of monitor housings was analysed. • The recyclable fraction mounts up to 85% for TV but only 53% of PC waste plastics. • A high percentage of pieces with bromine contents of over 50,000 ppm was obtained. - Abstract: This contribution is focused on the on-site determination of the bromine content in waste electrical and electronic equipment (WEEE), in particular waste plastics from television setsmore » (TV) and personal computer monitors (PC) using a handheld X-ray fluorescence (XRF) device. The described approach allows the examination of samples in regards to the compliance with legal specifications for polybrominated biphenyls (PBBs) and polybrominated diphenyl ethers (PBDEs) directly after disassembling and facilitates the sorting out of plastics with high contents of brominated flame retardants (BFRs). In all, over 3000 pieces of black (TV) and 1600 pieces of grey (PC) plastic waste were analysed with handheld XRF technique for this study. Especially noticeable was the high percentage of pieces with a bromine content of over 50,000 ppm for TV (7%) and PC (39%) waste plastics. The applied method was validated by comparing the data of handheld XRF with results obtained by GC–MS. The results showed the expected and sufficiently accurate correlation between these two methods. It is shown that handheld XRF technique is an effective tool for fast monitoring of large volumes of WEEE plastics in regards to BFRs for on-site measurements.« less

Size effects in olivine control strength in low-temperature plasticity regime

NASA Astrophysics Data System (ADS)

Kumamoto, K. M.; Thom, C.; Wallis, D.; Hansen, L. N.; Armstrong, D. E. J.; Goldsby, D. L.; Warren, J. M.; Wilkinson, A. J.

2017-12-01

The strength of the lithospheric mantle during deformation by low-temperature plasticity controls a range of geological phenomena, including lithospheric-scale strain localization, the evolution of friction on deep seismogenic faults, and the flexure of tectonic plates. However, constraints on the strength of olivine in this deformation regime are difficult to obtain from conventional rock-deformation experiments, and previous results vary considerably. We demonstrate via nanoindentation that the strength of olivine in the low-temperature plasticity regime is dependent on the length-scale of the test, with experiments on smaller volumes of material exhibiting larger yield stresses. This "size effect" has previously been explained in engineering materials as a result of the role of strain gradients and associated geometrically necessary dislocations in modifying plastic behavior. The Hall-Petch effect, in which a material with a small grain size exhibits a higher strength than one with a large grain size, is thought to arise from the same mechanism. The presence of a size effect resolves discrepancies among previous experimental measurements of olivine, which were either conducted using indentation methods or were conducted on polycrystalline samples with small grain sizes. An analysis of different low-temperature plasticity flow laws extrapolated to room temperature reveals a power-law relationship between length-scale (grain size for polycrystalline deformation and contact radius for indentation tests) and yield strength. This suggests that data from samples with large inherent length scales best represent the plastic strength of the coarse-grained lithospheric mantle. Additionally, the plastic deformation of nanometer- to micrometer-sized asperities on fault surfaces may control the evolution of fault roughness due to their size-dependent strength.

Functionalization of nanomaterials by non-thermal large area atmospheric pressure plasmas: application to flexible dye-sensitized solar cells.

PubMed

Jung, Heesoo; Park, Jaeyoung; Yoo, Eun Sang; Han, Gill-Sang; Jung, Hyun Suk; Ko, Min Jae; Park, Sanghoo; Choe, Wonho

2013-09-07

A key challenge to the industrial application of nanotechnology is the development of fabrication processes for functional devices based on nanomaterials which can be scaled up for mass production. In this report, we disclose the results of non-thermal radio-frequency (rf) atmospheric pressure plasma (APP) based deposition of TiO2 nanoparticles on a flexible substrate for the fabrication of dye-sensitized solar cells (DSSCs). Operating at 190 °C without a vacuum enclosure, the APP method can avoid thermal damage and vacuum compatibility restrictions and utilize roll-to-roll processing over a large area. The various analyses of the TiO2 films demonstrate that superior film properties can be obtained by the non-thermal APP method when compared with the thermal sintering process operating at 450 °C. The crystallinity of the anatase TiO2 nanoparticles is significantly improved without thermal agglomeration, while the surface defects such as Ti(3+) ions are eliminated, thus providing efficient charge collecting properties for solar cells. Finally, we successfully fabricated a flexible DSSC with an energy conversion efficiency of 4.2% using a transparent plastic substrate. This work demonstrates the potential of non-thermal APP technology in the area of device-level, nano-enabled material manufacturing.

Chemically Active, Porous 3D-Printed Thermoplastic Composites.

PubMed

Evans, Kent A; Kennedy, Zachary C; Arey, Bruce W; Christ, Josef F; Schaef, Herbert T; Nune, Satish K; Erikson, Rebecca L

2018-05-02

Metal-organic frameworks (MOFs) exhibit exceptional properties and are widely investigated because of their structural and functional versatility relevant to catalysis, separations, and sensing applications. However, their commercial or large-scale application is often limited by their powder forms which make integration into devices challenging. Here, we report the production of MOF-thermoplastic polymer composites in well-defined and customizable forms and with complex internal structural features accessed via a standard three-dimensional (3D) printer. MOFs (zeolitic imidazolate framework; ZIF-8) were incorporated homogeneously into both poly(lactic acid) (PLA) and thermoplastic polyurethane (TPU) matrices at high loadings (up to 50% by mass), extruded into filaments, and utilized for on-demand access to 3D structures by fused deposition modeling. Printed, rigid PLA/MOF composites display a large surface area (SA avg = 531 m 2 g -1 ) and hierarchical pore features, whereas flexible TPU/MOF composites achieve a high surface area (SA avg = 706 m 2 g -1 ) by employing a simple method developed to expose obstructed micropores postprinting. Critically, embedded particles in the plastic matrices retain their ability to participate in chemical interactions characteristic of the parent framework. The fabrication strategies were extended to other MOFs and illustrate the potential of 3D printing to create unique porous and high surface area chemically active structures.

Experimental evidence for intraplate deformation controlled by netlike plastic-flow in central-eastern Asia

NASA Astrophysics Data System (ADS)

Wang, Sheng-zu; Li, Jian-guo; Zhou, Yong-sheng

2007-12-01

The experimental results of brittle/ductile two-layer analogue models verify that intraplate tectonic deformation in central-eastern Asia is controlled mainly by the netlike plastic-flow (NPF) occurring in the lower lithosphere, including the lower crust and lithospheric mantle. The ductile lower layer in the model, corresponding to the lower lithosphere in the natural prototype, is made of a mixture of gum rosin and turpentine oil and the brittle upper one, to the upper crust, is formed by the consolidation of talc-powder slurry. The NPF hypothesis for continental dynamics can be regarded as a combination and development of two kinds of seemingly mutually exclusive ones, which are based on the theories of slip-line field and viscous (plastic) flow, respectively. In contrast to "homogeneous" viscous (plastic) flow considered usually in fluid mechanics and rheology, NPF is a viscous (plastic) flow accompanied with shear strain localization, forming plastic-flow network in the flow field. Plastic-flow network, being composed of two families of plastic-flow belts intersecting each other with their initial conjugate angles (i.e. the included angles facing the compression direction) equal to 90°, is similar to but different from the traditional slip-line network, which is assumed as a critical state of yield in elastoplastic medium. The experiments show that there are several NPF-controlled tectonic network systems to be developed in the models and two of them correspond to those in central-eastern Asia, which have the Himalayan and Taiwan arcs as their driving boundaries, respectively. The existence of "stable blocks" in the ductile lower layer has promoted some types of tectonic deformation, including the formation of large-scale compressional basins, corresponding to the Tarim, Ordos, Sichuan basins, etc., the development of compression-shear tectonic zones between some of these basins, corresponding to those shown by the Tianshan and Altay mountain ranges, and the uplift of some areas of the "plateau", corresponding to a contribution to the formation of the Qinghai-Tibet plateau. The distributions of maximum compressive stress directions and strains in the ductile lower layer estimated using the "conjugate-angle-bisector" and "conjugate-angle-increment" methods, respectively, are coincident in general tendency and framework with those in the prototype for the major part of the central-eastern Asian continent. It is also inferred that the westward influence of the horizontal compression component of the Pacific plate has reached North China by means of the interaction between adjacent plastic-flow networks although the tectonic network resulting directly from this horizontal compression has not spread westward beyond the Japan Sea.

Dynamic rupture models of subduction zone earthquakes with off-fault plasticity

NASA Astrophysics Data System (ADS)

Wollherr, S.; van Zelst, I.; Gabriel, A. A.; van Dinther, Y.; Madden, E. H.; Ulrich, T.

2017-12-01

Modeling tsunami-genesis based on purely elastic seafloor displacement typically underpredicts tsunami sizes. Dynamic rupture simulations allow to analyse whether plastic energy dissipation is a missing rheological component by capturing the complex interplay of the rupture front, emitted seismic waves and the free surface in the accretionary prism. Strike-slip models with off-fault plasticity suggest decreasing rupture speed and extensive plastic yielding mainly at shallow depths. For simplified subduction geometries inelastic deformation on the verge of Coulomb failure may enhance vertical displacement, which in turn favors the generation of large tsunamis (Ma, 2012). However, constraining appropriate initial conditions in terms of fault geometry, initial fault stress and strength remains challenging. Here, we present dynamic rupture models of subduction zones constrained by long-term seismo-thermo-mechanical modeling (STM) without any a priori assumption of regions of failure. The STM model provides self-consistent slab geometries, as well as stress and strength initial conditions which evolve in response to tectonic stresses, temperature, gravity, plasticity and pressure (van Dinther et al. 2013). Coseismic slip and coupled seismic wave propagation is modelled using the software package SeisSol (www.seissol.org), suited for complex fault zone structures and topography/bathymetry. SeisSol allows for local time-stepping, which drastically reduces the time-to-solution (Uphoff et al., 2017). This is particularly important in large-scale scenarios resolving small-scale features, such as the shallow angle between the megathrust fault and the free surface. Our dynamic rupture model uses a Drucker-Prager plastic yield criterion and accounts for thermal pressurization around the fault mimicking the effect of pore pressure changes due to frictional heating. We first analyze the influence of this rheology on rupture dynamics and tsunamigenic properties, i.e. seafloor displacement, in 2D. Finally, we use the same rheology in a large-scale 3D scenario of the 2004 Sumatra earthquake to shed light to the source process that caused the subsequent devastating tsunami.

Diflorasone Topical

MedlinePlus

... area, do not use tight-fitting diapers or plastic pants. Such use may increase side effects.Do not apply other skin preparations or products on the treated area without talking with your doctor.Do not wrap or bandage the treated area unless your doctor ...

Implementation of recycled cellulosic fibres into cement based composites and testing their influence on resulting properties

NASA Astrophysics Data System (ADS)

Hospodarova, V.; Stevulova, N.; Vaclavik, V.; Dvorsky, T.

2017-10-01

Nowadays, the application of raw materials from renewable sources such as wood, plants and waste paper to building materials preparing has gained a significant interest in this research area. The aim of this paper is to investigate the impact of the selected plasticizer on properties of fibres composites made of cellulosic fibres coming from recycled waste paper and cement. Investigations were performed on specimens with 0.5 wt. % of fibre addition without and with plasticizer. A comparative study did not show positive influence of plasticizer on the density and thermal conductivity of 28 days hardened composite. The specimens after 1, 3 and 7 days of hardening with plasticizer exhibited the highest impact on compressive strength in comparison to composite without plasticizer but 28 days hardened specimens reached the same value of strength characteristic (41 MPa).

Overexpression of Serum Response Factor in Neurons Restores Ocular Dominance Plasticity in a Model of Fetal Alcohol Spectrum Disorders

PubMed Central

Foxworthy, W. Alex; Medina, Alexandre E.

2015-01-01

Background Deficits in neuronal plasticity underlie many neurobehavioral and cognitive problems presented in Fetal Alcohol Spectrum Disorders (FASD). Our lab has developed a ferret model showing that early alcohol exposure leads to a persistent disruption in ocular dominance (OD) plasticity. For instance, a few days of monocular deprivation results in a robust reduction of visual cortex neurons’ responsiveness to stimulation of the deprived eye in normal animals, but not in ferrets with early alcohol exposure. Previously our lab demonstrated that overexpression of serum response factor (SRF) exclusively in astrocytes can improve neuronal plasticity in FASD. Here we test whether neuronal overexpression of SRF can achieve similar effects. Methods Ferrets received 3.5 g/kg alcohol i.p. (25% in saline) or saline as control every other day between postnatal day (P) 10 to 30, which is roughly equivalent to the third trimester of human gestation. Animals were given intracortical injections of a Herpes viral vector to express either GFP or a constitutively active form of SRF in infected neurons. They were then monocularly deprived by eyelid suture for 4–5 d after which single-unit recordings were conducted to determine if changes in ocular dominance had occurred. Results Overexpression of a constitutively active form of SRF by neurons restored OD plasticity in alcohol-treated animals. This effect was observed only in areas near the site of viral infection. Conclusions Overexpression of SRF in neurons can restore plasticity in the ferret model of FASD, but only in areas near the site of infection. This contrasts with SRF overexpression in astrocytes which restored plasticity throughout the visual cortex. PMID:26342644

Awareness and Perception of Plastic Surgery among Healthcare Professionals in Pune, India: Do They Really Know What We Do?

PubMed Central

Panse, Nikhil; Panse, Smita; Kulkarni, Priya; Dhongde, Rajendra; Sahasrabudhe, Parag

2012-01-01

Purpose. The aim of this study is to understand the level of awareness and knowledge of plastic surgery in healthcare professionals in a tertiary health care facility in Pune, India. This study also aims to highlight the perception of the medical professionals about plastic surgery and what they think a plastic surgeon does. Materials and Methods. A questionnaire-based survey was done at B.J Medical College and Sassoon Hospital, Pune in 2011. Feedback evaluation forms from hundred resident doctors and faculty were evaluated and analyzed. Results. There is not much awareness about plastic surgery as a specialty amongst health care providers. Plastic surgery is mostly perceived as cosmetic surgery, and the other spectrum of the patients we cater to goes largely unnoticed. Of all the clinical conditions given to the participants, there was not a single clinical condition where the respondents favored unanimously for plastic surgeons. Conclusion. Plastic surgery as a specialty is poorly understood by our medical colleagues, and the onus of creating and improving the awareness and perception of our specialty lies on us. Herculean unified efforts at individual as well as global level will help us achieve this goal. PMID:22685647

Plastic Pollution in the World's Oceans: More than 5 Trillion Plastic Pieces Weighing over 250,000 Tons Afloat at Sea.

PubMed

Eriksen, Marcus; Lebreton, Laurent C M; Carson, Henry S; Thiel, Martin; Moore, Charles J; Borerro, Jose C; Galgani, Francois; Ryan, Peter G; Reisser, Julia

2014-01-01

Plastic pollution is ubiquitous throughout the marine environment, yet estimates of the global abundance and weight of floating plastics have lacked data, particularly from the Southern Hemisphere and remote regions. Here we report an estimate of the total number of plastic particles and their weight floating in the world's oceans from 24 expeditions (2007-2013) across all five sub-tropical gyres, costal Australia, Bay of Bengal and the Mediterranean Sea conducting surface net tows (N = 680) and visual survey transects of large plastic debris (N = 891). Using an oceanographic model of floating debris dispersal calibrated by our data, and correcting for wind-driven vertical mixing, we estimate a minimum of 5.25 trillion particles weighing 268,940 tons. When comparing between four size classes, two microplastic <4.75 mm and meso- and macroplastic >4.75 mm, a tremendous loss of microplastics is observed from the sea surface compared to expected rates of fragmentation, suggesting there are mechanisms at play that remove <4.75 mm plastic particles from the ocean surface.

Plastic Pollution in the World's Oceans: More than 5 Trillion Plastic Pieces Weighing over 250,000 Tons Afloat at Sea

PubMed Central

Eriksen, Marcus; Lebreton, Laurent C. M.; Carson, Henry S.; Thiel, Martin; Moore, Charles J.; Borerro, Jose C.; Galgani, Francois; Ryan, Peter G.; Reisser, Julia

2014-01-01

Plastic pollution is ubiquitous throughout the marine environment, yet estimates of the global abundance and weight of floating plastics have lacked data, particularly from the Southern Hemisphere and remote regions. Here we report an estimate of the total number of plastic particles and their weight floating in the world's oceans from 24 expeditions (2007–2013) across all five sub-tropical gyres, costal Australia, Bay of Bengal and the Mediterranean Sea conducting surface net tows (N = 680) and visual survey transects of large plastic debris (N = 891). Using an oceanographic model of floating debris dispersal calibrated by our data, and correcting for wind-driven vertical mixing, we estimate a minimum of 5.25 trillion particles weighing 268,940 tons. When comparing between four size classes, two microplastic <4.75 mm and meso- and macroplastic >4.75 mm, a tremendous loss of microplastics is observed from the sea surface compared to expected rates of fragmentation, suggesting there are mechanisms at play that remove <4.75 mm plastic particles from the ocean surface. PMID:25494041

Plasticity and genetic adaptation mediate amphibian and reptile responses to climate change.

PubMed

Urban, Mark C; Richardson, Jonathan L; Freidenfelds, Nicole A

2014-01-01

Phenotypic plasticity and genetic adaptation are predicted to mitigate some of the negative biotic consequences of climate change. Here, we evaluate evidence for plastic and evolutionary responses to climate variation in amphibians and reptiles via a literature review and meta-analysis. We included studies that either document phenotypic changes through time or space. Plasticity had a clear and ubiquitous role in promoting phenotypic changes in response to climate variation. For adaptive evolution, we found no direct evidence for evolution of amphibians or reptiles in response to climate change over time. However, we found many studies that documented adaptive responses to climate along spatial gradients. Plasticity provided a mixture of adaptive and maladaptive responses to climate change, highlighting that plasticity frequently, but not always, could ameliorate climate change. Based on our review, we advocate for more experiments that survey genetic changes through time in response to climate change. Overall, plastic and genetic variation in amphibians and reptiles could buffer some of the formidable threats from climate change, but large uncertainties remain owing to limited data.

Effects of Waste Plastic on the Physical and Rheological Properties of Bitumen

NASA Astrophysics Data System (ADS)

Ezree Abdullah, Mohd; Asyiqin Ahmad, Nurul; Putra Jaya, Ramadhansyah; Hassan, Norhidayah Abdul; Yaacob, Haryati; Rosli Hainin, Mohd

2017-05-01

Plastic disposal is one of the major problems for developing countries like Malaysia, at the same time Malaysia needs a large network of roads for its smooth economic and social development. The limited source of bitumen needs a deep thinking to ensure fast road construction. Therefore, the use of plastic waste in road construction not only can help to protect environment but also able to help the road construction industry. The aims of this research are to study the effects of waste plastic on rheological properties of bitumen. Modified bitumen was prepared by using blending techniques. Bitumen was heated and plastic waste was slowly added. Rheological properties of bitumen were performance by penetration, softening point, viscosity and direct shear rheometer test. The results showed that when content of plastic waste increase, the penetration value, softening point and viscosity of bitumen also increase. Generally, plastic waste improves the performance of bitumen when it was added into bitumen. It can be said that the usage helps to improve the performance of the road pavement which also reduces the rutting effect.

Plasticity and genetic adaptation mediate amphibian and reptile responses to climate change

PubMed Central

Urban, Mark C; Richardson, Jonathan L; Freidenfelds, Nicole A

2014-01-01

Phenotypic plasticity and genetic adaptation are predicted to mitigate some of the negative biotic consequences of climate change. Here, we evaluate evidence for plastic and evolutionary responses to climate variation in amphibians and reptiles via a literature review and meta-analysis. We included studies that either document phenotypic changes through time or space. Plasticity had a clear and ubiquitous role in promoting phenotypic changes in response to climate variation. For adaptive evolution, we found no direct evidence for evolution of amphibians or reptiles in response to climate change over time. However, we found many studies that documented adaptive responses to climate along spatial gradients. Plasticity provided a mixture of adaptive and maladaptive responses to climate change, highlighting that plasticity frequently, but not always, could ameliorate climate change. Based on our review, we advocate for more experiments that survey genetic changes through time in response to climate change. Overall, plastic and genetic variation in amphibians and reptiles could buffer some of the formidable threats from climate change, but large uncertainties remain owing to limited data. PMID:24454550

The Danube so colourful: A potpourri of plastic litter outnumbers fish larvae in Europe's second largest river

PubMed Central

Lechner, Aaron; Keckeis, Hubert; Lumesberger-Loisl, Franz; Zens, Bernhard; Krusch, Reinhard; Tritthart, Michael; Glas, Martin; Schludermann, Elisabeth

2014-01-01

Previous studies on plastic pollution of aquatic ecosystems focused on the world's oceans. Large rivers as major pathways for land-based plastic litter, has received less attention so far. Here we report on plastic quantities in the Austrian Danube. A two year survey (2010, 2012) using stationary driftnets detected mean plastic abundance (n = 17,349; mean ± S.D: 316.8 ± 4664.6 items per 1000 m−3) and mass (4.8 ± 24.2 g per 1000 m−3) in the river to be higher than those of drifting larval fish (n = 24,049; 275.3 ± 745.0 individuals. 1000 m−3 and 3.2 ± 8.6 g 1000 m−3). Industrial raw material (pellets, flakes and spherules) accounted for substantial parts (79.4%) of the plastic debris. The plastic input via the Danube into the Black Sea was estimated to 4.2 t per day. PMID:24602762

Non-linear programming in shakedown analysis with plasticity and friction

NASA Astrophysics Data System (ADS)

Spagnoli, A.; Terzano, M.; Barber, J. R.; Klarbring, A.

2017-07-01

Complete frictional contacts, when subjected to cyclic loading, may sometimes develop a favourable situation where slip ceases after a few cycles, an occurrence commonly known as frictional shakedown. Its resemblance to shakedown in plasticity has prompted scholars to apply direct methods, derived from the classical theorems of limit analysis, in order to assess a safe limit to the external loads applied on the system. In circumstances where zones of plastic deformation develop in the material (e.g., because of the large stress concentrations near the sharp edges of a complete contact), it is reasonable to expect an effect of mutual interaction of frictional slip and plastic strains on the load limit below which the global behaviour is non dissipative, i.e., both slip and plastic strains go to zero after some dissipative load cycles. In this paper, shakedown of general two-dimensional discrete systems, involving both friction and plasticity, is discussed and the shakedown limit load is calculated using a non-linear programming algorithm based on the static theorem of limit analysis. An illustrative example related to an elastic-plastic solid containing a frictional crack is provided.

The Current Status of Somatostatin-Interneurons in Inhibitory Control of Brain Function and Plasticity

PubMed Central

2016-01-01

The mammalian neocortex contains many distinct inhibitory neuronal populations to balance excitatory neurotransmission. A correct excitation/inhibition equilibrium is crucial for normal brain development, functioning, and controlling lifelong cortical plasticity. Knowledge about how the inhibitory network contributes to brain plasticity however remains incomplete. Somatostatin- (SST-) interneurons constitute a large neocortical subpopulation of interneurons, next to parvalbumin- (PV-) and vasoactive intestinal peptide- (VIP-) interneurons. Unlike the extensively studied PV-interneurons, acknowledged as key components in guiding ocular dominance plasticity, the contribution of SST-interneurons is less understood. Nevertheless, SST-interneurons are ideally situated within cortical networks to integrate unimodal or cross-modal sensory information processing and therefore likely to be important mediators of experience-dependent plasticity. The lack of knowledge on SST-interneurons partially relates to the wide variety of distinct subpopulations present in the sensory neocortex. This review informs on those SST-subpopulations hitherto described based on anatomical, molecular, or electrophysiological characteristics and whose functional roles can be attributed based on specific cortical wiring patterns. A possible role for these subpopulations in experience-dependent plasticity will be discussed, emphasizing on learning-induced plasticity and on unimodal and cross-modal plasticity upon sensory loss. This knowledge will ultimately contribute to guide brain plasticity into well-defined directions to restore sensory function and promote lifelong learning. PMID:27403348

Effects of water stress on irradiance acclimation of leaf traits in almond trees.

PubMed

Egea, Gregorio; González-Real, María M; Baille, Alain; Nortes, Pedro A; Conesa, María R; Ruiz-Salleres, Isabel

2012-04-01

Photosynthetic acclimation to highly variable local irradiance within the tree crown plays a primary role in determining tree carbon uptake. This study explores the plasticity of leaf structural and physiological traits in response to the interactive effects of ontogeny, water stress and irradiance in adult almond trees that have been subjected to three water regimes (full irrigation, deficit irrigation and rain-fed) for a 3-year period (2006-08) in a semiarid climate. Leaf structural (dry mass per unit area, N and chlorophyll content) and photosynthetic (maximum net CO(2) assimilation, A(max), maximum stomatal conductance, g(s,max), and mesophyll conductance, g(m)) traits and stem-to-leaf hydraulic conductance (K(s-l)) were determined throughout the 2008 growing season in leaves of outer south-facing (S-leaves) and inner northwest-facing (NW-leaves) shoots. Leaf plasticity was quantified by means of an exposure adjustment coefficient (ε=1-X(NW)/X(S)) for each trait (X) of S- and NW-leaves. Photosynthetic traits and K(s-l) exhibited higher irradiance-elicited plasticity (higher ε) than structural traits in all treatments, with the highest and lowest plasticity being observed in the fully irrigated and rain-fed trees, respectively. Our results suggest that water stress modulates the irradiance-elicited plasticity of almond leaves through changes in crown architecture. Such changes lead to a more even distribution of within-crown irradiance, and hence of the photosynthetic capacity, as water stress intensifies. Ontogeny drove seasonal changes only in the ε of area- and mass-based N content and mass-based chlorophyll content, while no leaf age-dependent effect was observed on ε as regards the physiological traits. Our results also indicate that the irradiance-elicited plasticity of A(max) is mainly driven by changes in leaf dry mass per unit area, in g(m) and, most likely, in the partitioning of the leaf N content.

Plastic surgery and global health: how plastic surgery impacts the global burden of surgical disease.

PubMed

Semer, Nadine B; Sullivan, Stephen R; Meara, John G

2010-08-01

The global burden of surgical disease is estimated as being 11% of the total global burden of disease. In this article we discuss the portion of this burden which could be ameliorated with plastic surgical expertise. Although not necessarily seen as a major player in issues related to global health, plastic surgeons are uniquely qualified to decrease the burden of surgical disease afflicting people in the developing world. Burns, traumatic injuries, and congenital anomalies are some of the areas where the presence of plastic surgical expertise can make a significant difference in patient outcomes and thereby decrease the years of life lost due to disability due to these highly treatable conditions. In light of the severe shortage of plastic surgeons throughout the developing world, it falls to those concentrated in the developed world to harness their skills and address the vast unmet needs of the developing world so as to enhance global health. Copyright 2009 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved.

Microbial enzymes for the recycling of recalcitrant petroleum-based plastics: how far are we?

PubMed

Wei, Ren; Zimmermann, Wolfgang

2017-11-01

Petroleum-based plastics have replaced many natural materials in their former applications. With their excellent properties, they have found widespread uses in almost every area of human life. However, the high recalcitrance of many synthetic plastics results in their long persistence in the environment, and the growing amount of plastic waste ending up in landfills and in the oceans has become a global concern. In recent years, a number of microbial enzymes capable of modifying or degrading recalcitrant synthetic polymers have been identified. They are emerging as candidates for the development of biocatalytic plastic recycling processes, by which valuable raw materials can be recovered in an environmentally sustainable way. This review is focused on microbial biocatalysts involved in the degradation of the synthetic plastics polyethylene, polystyrene, polyurethane and polyethylene terephthalate (PET). Recent progress in the application of polyester hydrolases for the recovery of PET building blocks and challenges for the application of these enzymes in alternative plastic waste recycling processes will be discussed. © 2017 The Authors. Microbial Biotechnology published by John Wiley & Sons Ltd and Society for Applied Microbiology.

Biological degradation of plastics: a comprehensive review.

PubMed

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.

Research on Submarine Pipeline Steel with High Performance

NASA Astrophysics Data System (ADS)

Ren, Yi; Liu, Wenyue; Zhang, Shuai; Wang, Shuang; Gao, Hong

Submarine pipeline steel has largely uniform elongation, low yield ratio and good balance between high strength and high plasticity because of the microstructure with dual phase. In this work, the microstructure and properties of the submarine pipeline steel are studied. The results show that the matrix structure is consisted of ferrite, bainite and martensite -austenite islands. The structure has a tight relationship with the thermal-mechanical controlled process. Fine dual phase shows good plasticity and low yield ratio, which can support the good balance between high strength and high plasticity.

Plastic Surgery Response in Natural Disasters.

PubMed

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.

Thermodynamically consistent relations involving plasticity, internal energy and thermal effects.

PubMed

Schreyer, H L; Maudlin, P J

2005-11-15

Experimental data associated with plastic deformations indicate that the temperature is less than that predicted from dissipation based on plastic work. To obtain reasonable correlation between theoretical and experimental results, the plastic work is often multiplied by a constant beta. This paper provides an alternative thermodynamic framework in which it is proposed that there is an additional internal energy associated with dislocation pile-up or increase in dislocation density. The form of this internal energy follows from experimental data that relates flow stress to dislocation density and to equivalent plastic strain. The result is that beta is not a constant but a derived function. Representative results for beta and temperature as functions of effective plastic strain are provided for both an uncoupled and a coupled thermoplastic theory. In addition to providing features that are believed to be representative of many metals, the formulation can be used as a basis for more advanced theories such as those needed for large deformations and general forms of internal energy.

Separate collection of plastic waste, better than technical sorting from municipal solid waste?

PubMed

Feil, Alexander; Pretz, Thomas; Jansen, Michael; Thoden van Velzen, Eggo U

2017-02-01

The politically preferred solution to fulfil legal recycling demands is often implementing separate collection systems. However, experience shows their limitations, particularly in urban centres with a high population density. In response to the European Union landfill directive, mechanical biological waste treatment plants have been installed all over Europe. This technology makes it possible to retrieve plastic waste from municipal solid waste. Operators of mechanical biological waste treatment plants, both in Germany and the Netherlands, have started to change their mechanical separation processes to additionally produce plastic pre-concentrates. Results from mechanical biological waste treatment and separate collection of post-consumer packaging waste will be presented and compared. They prove that both the yield and the quality of plastic waste provided as feedstock for the production of secondary plastic raw material are largely comparable. An economic assessment shows which conditions for a technical sorting plant are economically attractive in comparison to separate collection systems. It is, however, unlikely that plastic recycling will ever reach cost neutrality.

Evaluation on the feasibility of using bamboo fillers in plastic gear manufacturing via the Taguchi optimization method

NASA Astrophysics Data System (ADS)

Mehat, N. M.; Kamaruddin, S.

2017-10-01

An increase in demand for industrial gears has instigated the escalating uses of plastic-matrix composites, particularly carbon or glass fibre reinforced plastics as gear material to enhance the properties and limitation in plastic gears. However, the production of large quantity of these synthetic fibres reinforced composites has posed serious threat to ecosystem. Therefore, this work is conducted to study the applicability and practical ability of using bamboo fillers particularly in plastic gear manufacturing as opposed to synthetic fibres via the Taguchi optimization method. The results showed that no failure mechanism such as gear tooth root cracking and severe tooth wear were observed in gear tested made of 5-30 wt% of bamboo fillers in comparing with the unfilled PP gear. These results indicated that bamboo can be practically and economically used as an alternative filler in plastic material reinforcement as well as in minimizing the cost of raw material in general.

Public perception of the field of plastic surgery.

PubMed

Gill, Patwinder; Bruscino-Raiola, Frank; Leung, Michael

2011-10-01

This study aims to assess the public's understanding of the scope of the practice of plastic surgeons, to determine if there is a need to increase awareness of the nature of a plastic surgeon's work. A cross-sectional study was performed. Participants were systematically selected from the White Pages for a telephone survey. The participants' demographics were recorded. Participants were excluded if they or anyone they knew had prior interactions with a plastic surgeon. Participants selected the most common area of specialization of plastic surgeons. The final set of questions determined their choice of surgeon in three different scenarios: breast reduction, excision of skin cancer from the facial region and hand trauma. Two hundred and thirteen of the 257 participants were eligible to complete the survey. Sixty-five per cent were female, with 38% between the ages of 46 and 65 years. The dominant field of practice was reconstructive surgery (36%). Just 19% of participants would consult plastic surgeons across the three clinical scenarios. Dermatologists (47%) were chosen over plastic surgeons (24%) to excise skin cancers from the face. Breast surgeons (53%) were chosen over plastic surgeons (23%) to perform breast reduction surgery. In hand trauma, 58% of participants would consult a hand surgeon and merely 10% would consult with plastic surgeons. The general public's understanding of plastic surgery is poor. This may be linked to the misunderstanding of specialist titles and lack of education regarding this field.

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

PubMed

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.

USARCENT AOR Contingency Base Waste Stream Analysis: An Analysis of Solid Waste Streams at Five Bases in the U. S. Army Central (USARCENT) Area of Responsibility

DTIC Science & Technology

2013-03-31

certainly remain comingled with other solid waste. For example, some bases provided containers for segregation of recyclables including plastic and...prevalent types of solid waste are food (19.1% by average sample weight), wood (18.9%), and plastics (16.0%) based on analysis of bases in...within the interval shown. Food and wood wastes are the largest components of the average waste stream (both at ~19% by weight), followed by plastic

EFFECTS OF NUMBER AND LOCATION OF BINS ON PLASTIC RECYCLING AT A UNIVERSITY

PubMed Central

O'Connor, Ryan T; Lerman, Dorothea C; Fritz, Jennifer N; Hodde, Henry B

2010-01-01

The proportion of plastic bottles that consumers placed in appropriate recycling receptacles rather than trash bins was examined across 3 buildings on a university campus. We extended previous research on interventions to increase recycling by controlling the number of recycling receptacles across conditions and by examining receptacle location without the use of posted signs. Manipulating the appearance or number of recycling bins in common areas did not increase recycling. Consumers recycled substantially more plastic bottles when the recycling bins were located in classrooms. PMID:21541154

Effects of number and location of bins on plastic recycling at a university.

PubMed

O'Connor, Ryan T; Lerman, Dorothea C; Fritz, Jennifer N; Hodde, Henry B

2010-01-01

The proportion of plastic bottles that consumers placed in appropriate recycling receptacles rather than trash bins was examined across 3 buildings on a university campus. We extended previous research on interventions to increase recycling by controlling the number of recycling receptacles across conditions and by examining receptacle location without the use of posted signs. Manipulating the appearance or number of recycling bins in common areas did not increase recycling. Consumers recycled substantially more plastic bottles when the recycling bins were located in classrooms.

Mountains to the sea: River study of plastic and non-plastic microfiber pollution in the northeast USA.

PubMed

Miller, Rachael Z; Watts, Andrew J R; Winslow, Brooke O; Galloway, Tamara S; Barrows, Abigail P W

2017-11-15

Aquatic environments are sinks for anthropogenic contamination, whether chemical or solid pollutants. Microfibers shed from clothing and other textiles contribute to this problem. These can be plastic or non-plastic origin. Our aim was to investigate the presence and distribution of both types of anthropogenic microfibers along the length of the Hudson River, USA. Surface grab samples were collected and filtered through a 0.45μm filter paper. Abundance of fibers was determined after subtraction of potential contamination. 233 microfibers were recorded in 142 samples, averaging 0.98microfibersL -1 . Subsequent micro-FTIR showed half of the fibers were plastic while the other half were non-plastic, but of anthropogenic origin. There was no relationship between fiber abundance, wastewater treatment plant location or population density. Extrapolating from this data, and using available hydrographic data, 34.4% of the Hudson River's watershed drainage area contributes an average 300 million anthropogenic microfibers into the Atlantic Ocean per day. Copyright © 2017 Elsevier Ltd. All rights reserved.

Amount and distribution of neustonic micro-plastic off the western Sardinian coast (Central-Western Mediterranean Sea).

PubMed

de Lucia, Giuseppe Andrea; Caliani, Ilaria; Marra, Stefano; Camedda, Andrea; Coppa, Stefania; Alcaro, Luigi; Campani, Tommaso; Giannetti, Matteo; Coppola, Daniele; Cicero, Anna Maria; Panti, Cristina; Baini, Matteo; Guerranti, Cristiana; Marsili, Letizia; Massaro, Giorgio; Fossi, Maria Cristina; Matiddi, Marco

2014-09-01

A plethora of different sampling methodologies has been used to document the presence of micro-plastic fragments in sea water. European Marine Strategy suggests to improve standard techniques to make future data comparable. We use Manta Trawl sampling technique to quantify abundance and distribution of micro-plastic fragments in Sardinian Sea (Western Mediterranean), and their relation with phthalates and organoclorine in the neustonic habitat. Our results highlight a quite high average plastic abundance value (0.15 items/m(3)), comparable to the levels detected in other areas of the Mediterranean. "Site" is the only factor that significantly explains the differences observed in micro-plastic densities. Contaminant levels show high spatial and temporal variation. In every station, HCB is the contaminant with the lowest concentration while PCBs shows the highest levels. This work, in line with Marine Strategy directives, represents a preliminary study for the analysis of plastic impact on marine environment of Sardinia. Copyright © 2014 Elsevier Ltd. All rights reserved.

Global change and the evolution of phenotypic plasticity in plants.

PubMed

Matesanz, Silvia; Gianoli, Ernesto; Valladares, Fernando

2010-09-01

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

Removal of area CA3 from hippocampal slices induces postsynaptic plasticity at Schaffer collateral synapses that normalizes CA1 pyramidal cell discharge.

PubMed

Dumas, Theodore C; Uttaro, Michael R; Barriga, Carolina; Brinkley, Tiffany; Halavi, Maryam; Wright, Susan N; Ferrante, Michele; Evans, Rebekah C; Hawes, Sarah L; Sanders, Erin M

2018-06-21

Neural networks that undergo acute insults display remarkable reorganization. This injury related plasticity is thought to permit recovery of function in the face of damage that cannot be reversed. Previously, an increase in the transmission strength at Schaffer collateral to CA1 pyramidal cell synapses was observed after long-term activity reduction in organotypic hippocampal slices. Here we report that, following acute preparation of adult rat hippocampal slices and surgical removal of area CA3, input to area CA1 was reduced and Schaffer collateral synapses underwent functional strengthening. This increase in synaptic strength was limited to Schaffer collateral inputs (no alteration to temporoammonic synapses) and acted to normalize postsynaptic discharge, supporting a homeostatic or compensatory response. Short-term plasticity was not altered, but an increase in immunohistochemical labeling of GluA1 subunits was observed in the stratum radiatum (but not stratum moleculare), suggesting increased numbers of α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptors and a postsynaptic locus of expression. Combined, these data support the idea that, in response to the reduction in presynaptic activity caused by removal of area CA3, Schaffer collateral synapses undergo a relatively rapid increase in functional efficacy likely supported by insertion of more AMPARs, which maintains postsynaptic excitability in CA1 pyramidal neurons. This novel fast compensatory plasticity exhibits properties that would allow it to maintain optimal network activity levels in the hippocampus, a brain structure lauded for its ongoing experience-dependent malleability. Copyright © 2018 Elsevier B.V. All rights reserved.

Recent advances in continuum plasticity: phenomenological modeling and experimentation using X-ray diffraction

NASA Astrophysics Data System (ADS)

Edmiston, John Kearney

This work explores the field of continuum plasticity from two fronts. On the theory side, we establish a complete specification of a phenomenological theory of plasticity for single crystals. The model serves as an alternative to the popular crystal plasticity formulation. Such a model has been previously proposed in the literature; the new contribution made here is the constitutive framework and resulting simulations. We calibrate the model to available data and use a simple numerical method to explore resulting predictions in plane strain boundary value problems. Results show promise for further investigation of the plasticity model. Conveniently, this theory comes with a corresponding experimental tool in X-ray diffraction. Recent advances in hardware technology at synchrotron sources have led to an increased use of the technique for studies of plasticity in the bulk of materials. The method has been successful in qualitative observations of material behavior, but its use in quantitative studies seeking to extract material properties is open for investigation. Therefore in the second component of the thesis several contributions are made to synchrotron X-ray diffraction experiments, in terms of method development as well as the quantitative reporting of constitutive parameters. In the area of method development, analytical tools are developed to determine the available precision of this type of experiment—a crucial aspect to determine if the method is to be used for quantitative studies. We also extract kinematic information relating to intragranular inhomogeneity which is not accessible with traditional methods of data analysis. In the area of constitutive parameter identification, we use the method to extract parameters corresponding to the proposed formulation of plasticity for a titanium alloy (HCP) which is continuously sampled by X-ray diffraction during uniaxial extension. These results and the lessons learned from the efforts constitute early reporting of the quantitative profitability of undertaking such a line of experimentation for the study of plastic deformation processes.

Flat-Cladding Fiber Bragg Grating Sensors for Large Strain Amplitude Fatigue Tests

PubMed Central

Feng, Aihen; Chen, Daolun; Li, Cheng; Gu, Xijia

2010-01-01

We have successfully developed a flat-cladding fiber Bragg grating sensor for large cyclic strain amplitude tests of up to ±8,000 με. The increased contact area between the flat-cladding fiber and substrate, together with the application of a new bonding process, has significantly increased the bonding strength. In the push-pull fatigue tests of an aluminum alloy, the plastic strain amplitudes measured by three optical fiber sensors differ only by 0.43% at a cyclic strain amplitude of ±7,000 με and 1.9% at a cyclic strain amplitude of ±8,000 με. We also applied the sensor on an extruded magnesium alloy for evaluating the peculiar asymmetric hysteresis loops. The results obtained were in good agreement with those measured from the extensometer, a further validation of the sensor. PMID:22163621

Large area emulsion chamber experiments for the Space Shuttle

NASA Technical Reports Server (NTRS)

Parnell, T. A.

1985-01-01

Emulsion-chamber experiments employing nuclear-track emulsions, etchable plastic detectors, metal plates, and X-ray films continue to demonstrate high productivity and potential in the study of cosmic-ray primaries and their interactions. Emulsions, with unsurpassed track-recording capability, provide an appropriate medium for the study of nucleus-nucleus interactions at high energy, which will likely produce observations of a phase change in nuclear matter. The many advantages of emulsion chambers (excellent multitrack recording capability, large geometry factor, low apparatus cost, simplicity of design and construction) are complemented by the major advantages of the Space Shuttle as an experiment carrier. A Shuttle experiment which could make a significant advance in both cosmic-ray primary and nucleus-nucleus interaction studies is described. Such an experiment would serve as a guide for use of emulsions during the Space Station era. Some practical factors that must be considered in planning a Shuttle exposure of emulsion chambers are discussed.

Evolution of twinning in extruded AZ31 alloy with bimodal grain structure

DOE Office of Scientific and Technical Information (OSTI.GOV)

Garcés, G., E-mail: ggarces@cenim.csic.es

2017-04-15

Twinning in extruded AZ31 alloy with a bimodal grain structure is studied under compression along the extrusion direction. This study has combined in-situ measurements during the compression tests by Synchrotron Radiation Diffraction and Acoustic Emission techniques and the evaluation of the microstructure and texture in post-mortem compression samples deformed at different strains. The microstructure of the alloy is characterized by the coexistence of large areas of fine dynamic recrystallized grains and coarse non-recrystallized grains elongated along extrusion direction. Twinning occurs initially in large elongated grains before the macroscopic yield stress which is controlled by the twinning in equiaxed dynamically recrystallizedmore » grains. - Highlights: • The AZ31 extruded at low temperature exhibits a bimodal grains structure. • Twinning takes place before macroscopic yielding in coarse non-DRXed grains. • DRXed grains controls the beginning of plasticity in magnesium alloys with bimodal grain structure.« less

Water pollutant fingerprinting tracks recent industrial transfer from coastal to inland China: A case study

PubMed Central

Zheng, Weiwei; Wang, Xia; Tian, Dajun; Jiang, Songhui; Andersen, Melvin E.; He, Genhsjeng; Crabbe, M. James C.; Zheng, Yuxin; Zhong, Yang; Qu, Weidong

2013-01-01

In recent years, China’s developed regions have transferred industries to undeveloped regions. Large numbers of unlicensed or unregistered enterprises are widespread in these undeveloped regions and they are subject to minimal regulation. Current methods for tracing industrial transfers in these areas, based on enterprise registration information or economic surveys, do not work. We have developed an analytical framework combining water fingerprinting and evolutionary analysis to trace the pollution transfer features between water sources. We collected samples in Eastern China (industrial export) and Central China (industrial acceptance) separately from two water systems. Based on the water pollutant fingerprints and evolutionary trees, we traced the pollution transfer associated with industrial transfer between the two areas. The results are consistent with four episodes of industrial transfers over the past decade. Our results also show likely types of the transferred industries - electronics, plastics, and biomedicines - that contribute to the water pollution transfer. PMID:23301152

Water pollutant fingerprinting tracks recent industrial transfer from coastal to inland China: A case study

NASA Astrophysics Data System (ADS)

Zheng, Weiwei; Wang, Xia; Tian, Dajun; Jiang, Songhui; Andersen, Melvin E.; He, Genhsjeng; Crabbe, M. James C.; Zheng, Yuxin; Zhong, Yang; Qu, Weidong

2013-01-01

In recent years, China's developed regions have transferred industries to undeveloped regions. Large numbers of unlicensed or unregistered enterprises are widespread in these undeveloped regions and they are subject to minimal regulation. Current methods for tracing industrial transfers in these areas, based on enterprise registration information or economic surveys, do not work. We have developed an analytical framework combining water fingerprinting and evolutionary analysis to trace the pollution transfer features between water sources. We collected samples in Eastern China (industrial export) and Central China (industrial acceptance) separately from two water systems. Based on the water pollutant fingerprints and evolutionary trees, we traced the pollution transfer associated with industrial transfer between the two areas. The results are consistent with four episodes of industrial transfers over the past decade. Our results also show likely types of the transferred industries - electronics, plastics, and biomedicines - that contribute to the water pollution transfer.

The Portuguese plastic carrier bag tax: The effects on consumers' behavior.

PubMed

Martinho, Graça; Balaia, Natacha; Pires, Ana

2017-03-01

Marine litter from lightweight plastic bags is a global problem that must be solved. A plastic bag tax was implemented in February 2015 to reduce the consumption of plastic grocery bags in Portugal and in turn reduce the potential contribution to marine litter. This study analyzes the effect of the plastic bag tax on consumer behavior to learn how it was received and determine the perceived effectiveness of the tax 4months after its implementation. In addition, the study assessed how proximity to coastal areas could influence behaviors and opinions. The results showed a 74% reduction of plastic bag consumption with a simultaneously 61% increase of reusable plastic bags after the tax was implemented. Because plastic bags were then reused for shopping instead of garbage bags, however, the consumption of garbage bags increased by 12%. Although reduction was achieved, the tax had no effect on the perception of marine litter or the impact of plastic bags on environment and health. The majority of respondents agree with the tax but view it as an extra revenue to the State. The distance to the coast had no meaningful influence on consumer behavior or on the perception of the tax. Although the tax was able to promote the reduction of plastics, the role of hypermarkets and supermarkets in providing alternatives through the distribution of reusable plastic bags was determinant to ensuring the reduction. Copyright © 2017 Elsevier Ltd. All rights reserved.

Elastic and plastic strain measurement in high temperature environment using laser speckle

NASA Technical Reports Server (NTRS)

Chiang, Fu-Pen

1992-01-01

Two laser speckle methods are described to measure strain in high temperature environment and thermal strain caused by high temperature. Both are non-contact, non-destructive and remote sensing techniques that can be automated. The methods have different but overlapping ranges of application with one being more suitable for large plastic deformation.

Evolution of phenotypic plasticity and environmental tolerance of a labile quantitative character in a fluctuating environment.

PubMed

Lande, R

2014-05-01

Quantitative genetic models of evolution of phenotypic plasticity are used to derive environmental tolerance curves for a population in a changing environment, providing a theoretical foundation for integrating physiological and community ecology with evolutionary genetics of plasticity and norms of reaction. Plasticity is modelled for a labile quantitative character undergoing continuous reversible development and selection in a fluctuating environment. If there is no cost of plasticity, a labile character evolves expected plasticity equalling the slope of the optimal phenotype as a function of the environment. This contrasts with previous theory for plasticity influenced by the environment at a critical stage of early development determining a constant adult phenotype on which selection acts, for which the expected plasticity is reduced by the environmental predictability over the discrete time lag between development and selection. With a cost of plasticity in a labile character, the expected plasticity depends on the cost and on the environmental variance and predictability averaged over the continuous developmental time lag. Environmental tolerance curves derived from this model confirm traditional assumptions in physiological ecology and provide new insights. Tolerance curve width increases with larger environmental variance, but can only evolve within a limited range. The strength of the trade-off between tolerance curve height and width depends on the cost of plasticity. Asymmetric tolerance curves caused by male sterility at high temperature are illustrated. A simple condition is given for a large transient increase in plasticity and tolerance curve width following a sudden change in average environment. © 2014 The Author. Journal of Evolutionary Biology © 2014 European Society For Evolutionary Biology.

Economics of fabricating plastic preforms by robotics

NASA Astrophysics Data System (ADS)

Lundgren, E. M.

1985-08-01

A robotic work cell consisting of a process robot, an automatic weigh feeder, and an existing plastic pill making machine was developed. This work cell was released September 13, 1983, for production use. Although the work cell was designed and planned for operation in an operator-unattended mode, renovation and rearrangement of the work area made it necessary to assemble the work cell in the Robot Application Center Annex and to implement its initial use in production as an operator-attended work cell. Because the work cell is located in an area distant from the normal work area, an operator cannot monitor this and other equipment conveniently. As of September 1, 1984, the plastic pill making robot work cell has produced 80,428 pills in 752.8 hours, a reduction of 683.4 hours from the 1436.2 hours manual operation would have required. The next step in the development of automated pill making will occur when the work cell is relocated into the production department with a new pill press. Projections for future savings of $20,866 annually are based on a reduction of 1448 labor hours.

[Concentration and risk assessment of DEHP in vegetables around plastic industrial area].

PubMed

Wang, Jia-Wen; Du, Qi-Zhen; Song, Ying-Qi

2010-10-01

Concentration of di-(2-ethylhexyl) phthalate (DEHP)in the inner tissue of various vegetable species and their growing environment (soil and atmosphere) around plastic industrial area were investigated and determined by gas chromatography-mass spectrum (GC/MS). The results showed that concentrations of DEHP in 5 kinds of vegetable were 0.23-9.11 mg/kg, 3.82 mg/kg in average (fresh weight). Of the various vegetable species determined, the highest burden was observed in the leafy vegetables, followed by melon and root vegetables. Statistical analysis of variance showed that environment and species are the factors that significantly affect DEHP concentrations in inner vegetable tissue and soil, respectively. Atmosphere deposition is the principal pathway for the accumulation of DEHP. The ability of the plant accumulating DEHP was mainly influenced by the lipid content of the plant. Leaf with pubescence or rough surface was found to have higher DEHP than the other, when the lipid contents were similar. Evaluation of the vegetable around plastic industrial area with the acceptable daily intake (ADI) by OEHHA, concentrations of DEHP has exceeded the safety standard.

76 FR 51314 - Approval and Promulgation of Air Quality Implementation Plans; Maryland; Adoption of Drum and...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-08-18

... Miscellaneous Metal and Plastic Parts Coatings and will help Maryland attain and maintain the National Ambient... adoption of the drum and pail coating standards found in the Miscellaneous Metal and Plastic Parts Coatings... the area's date of attainment. CTGs are intended to provide state and local air pollution control...

[Trial manufacture of a plunger shield for a disposable plastic syringe].

PubMed

Murakami, Shigeki; Emoto, Takashi; Mori, Hiroshige; Fujita, Katsuhisa; Kubo, Naoki

2008-08-20

A syringe-type radiopharmaceutical being supplied by a manufacturer has a syringe shield and a plunger shield, whereas an in-hospital labeling radiopharmaceutical is administered by a disposable plastic syringe without the plunger shield. In cooperation with Nihon Medi-Physics Co. Ltd., we have produced a new experimental plunger shield for the disposable plastic syringe. In order to evaluate this shielding effect, we compared the leaked radiation doses of our plunger shield with those of the syringe-type radiopharmaceutical (Medi shield type). Our plunger shield has a lead plate of 21 mm in diameter and 3 mm thick. This shield is equipped with the plunger-end of a disposal plastic syringe. We sealed 99mTc solution into a plastic syringe (Terumo Co.) of 5 ml with our plunger shield and Medi shield type of 2 ml. We measured leaked radiation doses around syringes using fluorescent glass dosimeters (Dose Ace). The number of measure points was 18. The measured doses were converted to 70 microm dose equivalent at 740 MBq of radioactivity. The results of our plunger shield and the Medi shield type were as follows: 4-13 microSv/h and 3-14 microSv/h at shielding areas, 3-545 microSv/h and 6-97 microSv/h at non-shielding areas, 42-116 microSv/h and 88-165 microSv/h in the vicinity of the syringe shield, and 1071 microSv/h and 1243 microSv/h at the front of the needle. For dose rates of shielding areas around the syringe, the shielding effects were approximately the same as those of the Medi shield type. In conclusion, our plunger shield may be useful for reducing finger exposure during the injection of an in-hospital labeled radiopharmaceutical.

High within-canopy variation in isoprene emission potentials in temperate trees: Implications for predicting canopy-scale isoprene fluxes

NASA Astrophysics Data System (ADS)

Niinemets, ÜLo; Copolovici, Lucian; Hüve, Katja

2010-12-01

Isoprene emission potential (ES) varies in tree canopies, and such variations have potentially major implications for predicting canopy level emissions. So far, quantitative relationships of ES with irradiance are missing, and interspecific variation in ES plasticity and potential effects on canopy level emissions have not been characterized. ES, foliage structural, chemical, and photosynthetic characteristics were studied relative to integrated within-canopy daily quantum flux density (Qint) in temperate deciduous tree species Quercus robur, Populus tremula, Salix alba, and Salix caprea, and canopy isoprene emissions were calculated considering observed variation in ES and under different simplifying assumptions. Strong positive curvilinear relationships between nitrogen and dry mass per unit area, photosynthetic potentials and ES per area with Qint were observed. Structural, chemical, and photosynthetic traits varied 1.5-fold to 4-fold and ES per area 3-fold to 27-fold within the canopy. ES variation reflected accumulation of mesophyll cell layers and greater emission capacity of average cells. Species with largest structural and photosynthetic plasticity had greatest plasticity in ES. Relative to the simulation considering within-canopy variation in ES, the bias from assuming a constant ES varied between -8% and +68%, and it scaled positively with ES plasticity. The bias of big-leaf simulations varied between -22% and -35%, and it scaled negatively with ES plasticity. A generalized canopy response function of ES developed for all species resulted in the lowest bias between -11% and 6% and can be recommended for practical applications. The results highlight huge within-canopy and interspecific variation in ES and demonstrate that ignoring these variations strongly biases canopy emission predictions.

Slip-activated surface creep with room-temperature super-elongation in metallic nanocrystals

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhong, Li; Sansoz, Frederic; He, Yang

2016-11-28

Atom diffusion assisted by surfaces or interfaces (e.g. Coble creep) has been known to be the origin of large creep rates and superplastic softening in nanosized crystals at low temperature. By contrast, source-limited crystal slip in defect-free nanostructures engenders important strengths, but also premature plastic instability and low ductility. Here, using in-situ transmission electron microscopy, we report a slip-activated surface creep mechanism that suppresses the tendency towards plastic instability without compromising the strength, resulting in ultra-large room-temperature plasticity in face-centered-cubic silver nanocrystals. This phenomenon is shown experimentally and theoretically to prevail over a material-dependent range of diameters where surface dislocationmore » nucleation becomes a stimulus to diffusional creep. This work provides new fundamental insight into coupled diffusive-displacive deformation mechanisms maximizing ductility and strength simultaneously in nanoscale materials.« less

Individual differences in behavioural plasticities.

PubMed

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 plasticities observed at a given age. Several authors have predicted correlations across individuals between different types of behavioural plasticities, i.e. that some individuals will be generally more plastic than others. However, empirical support for most of these predictions, including indirect evidence from studies of relationships between personality traits and plasticities, is currently sparse and equivocal. The final section of this review suggests how an appreciation of the similarities and differences between different types of behavioural plasticities may help theoreticians formulate testable models to explain the evolution of individual differences in behavioural plasticities and the evolutionary and ecological consequences of individual differences in behavioural plasticities. © 2015 Cambridge Philosophical Society.

"Visual" Cortex of Congenitally Blind Adults Responds to Syntactic Movement.

PubMed

Lane, Connor; Kanjlia, Shipra; Omaki, Akira; Bedny, Marina

2015-09-16

Human cortex is comprised of specialized networks that support functions, such as visual motion perception and language processing. How do genes and experience contribute to this specialization? Studies of plasticity offer unique insights into this question. In congenitally blind individuals, "visual" cortex responds to auditory and tactile stimuli. Remarkably, recent evidence suggests that occipital areas participate in language processing. We asked whether in blindness, occipital cortices: (1) develop domain-specific responses to language and (2) respond to a highly specialized aspect of language-syntactic movement. Nineteen congenitally blind and 18 sighted participants took part in two fMRI experiments. We report that in congenitally blind individuals, but not in sighted controls, "visual" cortex is more active during sentence comprehension than during a sequence memory task with nonwords, or a symbolic math task. This suggests that areas of occipital cortex become selective for language, relative to other similar higher-cognitive tasks. Crucially, we find that these occipital areas respond more to sentences with syntactic movement but do not respond to the difficulty of math equations. We conclude that regions within the visual cortex of blind adults are involved in syntactic processing. Our findings suggest that the cognitive function of human cortical areas is largely determined by input during development. Human cortex is made up of specialized regions that perform different functions, such as visual motion perception and language processing. How do genes and experience contribute to this specialization? Studies of plasticity show that cortical areas can change function from one sensory modality to another. Here we demonstrate that input during development can alter cortical function even more dramatically. In blindness a subset of "visual" areas becomes specialized for language processing. Crucially, we find that the same "visual" areas respond to a highly specialized and uniquely human aspect of language-syntactic movement. These data suggest that human cortex has broad functional capacity during development, and input plays a major role in determining functional specialization. Copyright © 2015 the authors 0270-6474/15/3512859-10$15.00/0.

Response variance in functional maps: neural darwinism revisited.

PubMed

Takahashi, Hirokazu; Yokota, Ryo; Kanzaki, Ryohei

2013-01-01

The mechanisms by which functional maps and map plasticity contribute to cortical computation remain controversial. Recent studies have revisited the theory of neural Darwinism to interpret the learning-induced map plasticity and neuronal heterogeneity observed in the cortex. Here, we hypothesize that the Darwinian principle provides a substrate to explain the relationship between neuron heterogeneity and cortical functional maps. We demonstrate in the rat auditory cortex that the degree of response variance is closely correlated with the size of its representational area. Further, we show that the response variance within a given population is altered through training. These results suggest that larger representational areas may help to accommodate heterogeneous populations of neurons. Thus, functional maps and map plasticity are likely to play essential roles in Darwinian computation, serving as effective, but not absolutely necessary, structures to generate diverse response properties within a neural population.

Response Variance in Functional Maps: Neural Darwinism Revisited

PubMed Central

Takahashi, Hirokazu; Yokota, Ryo; Kanzaki, Ryohei

2013-01-01

The mechanisms by which functional maps and map plasticity contribute to cortical computation remain controversial. Recent studies have revisited the theory of neural Darwinism to interpret the learning-induced map plasticity and neuronal heterogeneity observed in the cortex. Here, we hypothesize that the Darwinian principle provides a substrate to explain the relationship between neuron heterogeneity and cortical functional maps. We demonstrate in the rat auditory cortex that the degree of response variance is closely correlated with the size of its representational area. Further, we show that the response variance within a given population is altered through training. These results suggest that larger representational areas may help to accommodate heterogeneous populations of neurons. Thus, functional maps and map plasticity are likely to play essential roles in Darwinian computation, serving as effective, but not absolutely necessary, structures to generate diverse response properties within a neural population. PMID:23874733

Sequential shrink photolithography for plastic microlens arrays

NASA Astrophysics Data System (ADS)

Dyer, David; Shreim, Samir; Jayadev, Shreshta; Lew, Valerie; Botvinick, Elliot; Khine, Michelle

2011-07-01

Endeavoring to push the boundaries of microfabrication with shrinkable polymers, we have developed a sequential shrink photolithography process. We demonstrate the utility of this approach by rapidly fabricating plastic microlens arrays. First, we create a mask out of the children's toy Shrinky Dinks by simply printing dots using a standard desktop printer. Upon retraction of this pre-stressed thermoplastic sheet, the dots shrink to a fraction of their original size, which we then lithographically transfer onto photoresist-coated commodity shrink wrap film. This shrink film reduces in area by 95% when briefly heated, creating smooth convex photoresist bumps down to 30 µm. Taken together, this sequential shrink process provides a complete process to create microlenses, with an almost 99% reduction in area from the original pattern size. Finally, with a lithography molding step, we emboss these bumps into optical grade plastics such as cyclic olefin copolymer for functional microlens arrays.

Aesthetic Training for Plastic Surgeons: Are Residents Getting Enough?

PubMed

Papas, Athanasios; Montemurro, Paolo; Hedén, Per

2018-02-01

Plastic Surgery is one of the most competitive specialties in the field of medicine. However, this specialty has a unique particularity: the difficulties in Aesthetic Surgery training within the residency program. Despite the fact that the full title of the specialty is Plastic, Reconstructive, and Aesthetic Surgery and that Aesthetic Surgery is a part of the examination syllabus, the actual training in the specific area is limited. One of the solutions to this problem is Fellowships. The first author describes his personal experience with Aesthetic training and how it enhanced his knowledge in the area as well as the status of Fellowships in various training programs. 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.

Sequential shrink photolithography for plastic microlens arrays.

PubMed

Dyer, David; Shreim, Samir; Jayadev, Shreshta; Lew, Valerie; Botvinick, Elliot; Khine, Michelle

2011-07-18

Endeavoring to push the boundaries of microfabrication with shrinkable polymers, we have developed a sequential shrink photolithography process. We demonstrate the utility of this approach by rapidly fabricating plastic microlens arrays. First, we create a mask out of the children's toy Shrinky Dinks by simply printing dots using a standard desktop printer. Upon retraction of this pre-stressed thermoplastic sheet, the dots shrink to a fraction of their original size, which we then lithographically transfer onto photoresist-coated commodity shrink wrap film. This shrink film reduces in area by 95% when briefly heated, creating smooth convex photoresist bumps down to 30 µm. Taken together, this sequential shrink process provides a complete process to create microlenses, with an almost 99% reduction in area from the original pattern size. Finally, with a lithography molding step, we emboss these bumps into optical grade plastics such as cyclic olefin copolymer for functional microlens arrays.