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Recycling Process (recycling + process)
Selected AbstractsThe roles of actin cytoskeleton and microtubules for membrane recycling of a food vacuole in Tetrahymena thermophilaCYTOSKELETON, Issue 7 2009Maki Sugita Abstract Phagocytosis is a fundamental cellular event for the uptake of nutrients from the environment in several kinds of eukaryote. Most ciliates egest waste and undigested materials in food vacuoles (FVs) through a cytoproct, which is a specific organelle for defecation. It is considered that FV egestion is initiated by fusion between the FV membrane and plasma membrane in a cytoproct and completed with retrieval of the membrane into a cytoplasmic space. In addition, electron microscopy indicated that microfilaments might be involved in the recycling process of the FV membrane in ciliates over 30 years ago; however, there is no conclusive evidence. Here we demonstrated actin organization on FV near a cytoproct in Tetrahymena thermophila by using a marker for a cytoproct. Moreover, it was revealed that cells treated with actin cytoskeletal inhibitor, Latrunculin B, might be suppressed for membrane retrieval in a cytoproct following FV egestion. On the other hand, the actin structures, likely to be the site of membrane retrieval, were frequently observed in the cells treated with cytoplasmic microtubules inhibitor, Nocodazole. We concluded that actin filaments were probably required for recycling of the FV membrane in a cytoproct although the role was not essential for FV egestion. In addition, it was possible that microtubules might be involved in transportation of recycling vesicles of FV coated with F-actin. Cell Motil. Cytoskeleton 2009. © 2009 Wiley-Liss, Inc. [source] Analysing metals in bottle-grade poly(ethylene terephthalate) by X-ray fluorescence spectrometryJOURNAL OF APPLIED POLYMER SCIENCE, Issue 5 2010Wanderson Romão Abstract After a rigorous cleaning process, recycled food-grade poly(ethylene terephthalate) (PET), can be mixed with virgin PET resin in different concentrations and used for packaging of soft drinks. Therefore, it is important to have an experimental method to distinguish the presence of recycled polymer in a batch and to check its "true quality." One of the issues to be verified is the presence of inorganic contaminants due to the recycling process. X-ray fluorescence technique is one alternative for this kind of analysis. The results obtained in this work show that bottle-grade PET samples (PET-btg) are made either via direct esterification or by a transesterification process. Samples that were subjected to thermo-mechanical processings (superclean® processing, PET-btg blends processed in our laboratory and soft drink PET packaging) present Fe K, emission lines with higher intensities than those presented by virgin bottle-grade PET. After applying principal component analysis, it can be concluded that Fe is an intrinsic contaminant after the recycling process, furnishing a way to indicate class separations of PET-btg. A calibration and validation partial least squares model was constructed to predict the weight percent of post-consumption bottle-grade PET in commercial PET samples. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010 [source] Recycling and Landfilling in a Dynamic Sraffian Model: Application of the Corn,guano Model to a Waste Treatment problemMETROECONOMICA, Issue 3 2001Eiji HosodaArticle first published online: 17 DEC 200 Landfill sites may be regarded as input for a waste treatment process. Considering landfill as an exhaustible resource, we apply a basic corn,guano model to a waste treatment problem. We show how dynamic substitution between landfilling and recycling occurs. Namely, in an early stage, landfill disposal is adopted as waste treatment and a recycling process is not activated. Once an economy faces exhaustion of landfill, a recycling process is activated as a backstop technology. We refer to the possibility that an economy may be unstable after exhaustion of landfill, even if it enjoys stable growth at the early stage. [source] ENDOGENOUS CONSUMER PARTICIPATION AND THE RECYCLING PROBLEM,AUSTRALIAN ECONOMIC PAPERS, Issue 4 2009SOHAM BAKSI We endogenise the extent of consumer participation in the recycling process, and analyse its effect on the ,recycling problem'. When recycling requires consumers to undertake costly sorting activities to separate scrap from household waste, they will participate only if the net reward from sorting is positive. Consumers' sorting cost is subject to a network effect arising due to social norms. With heterogeneous consumers differing in terms of their sorting cost, the entire output of the recyclable product may not be subsequently available as scrap to the recycling firms. This increases the virgin producer's monopoly power, and may also lead to multiple equilibria if the network effect of sorting is sufficiently large. The latter result suggests a role for the government in influencing equilibrium selection to improve social welfare. Depending on the fraction of consumers that participate in recycling, increased societal pressure on consumers to recycle may decrease consumer participation and increase the virgin producer's market power. [source] Quality Concepts for the Improved Use of Recycled Polymeric Materials: A ReviewMACROMOLECULAR MATERIALS & ENGINEERING, Issue 4 2008Francisco Vilaplana Abstract Polymeric waste materials should be considered resources for the manufacture of new products through recycling processes, with a similar status to virgin fossil-based plastics and biopolymers from renewable resources. Several efforts can be made to achieve this qualitative quantum leap in plastics recycling, and consequently introduce recycled products, with competitive performance, to the market. Scientific knowledge about the degradation processes during the life cycle and the development of fast and reliable analytical methods for the quality assessment of recycled plastics are fundamental to guarantee their performance in new applications. Different strategies,restabilisation, rebuilding, compatibilisation, and addition of elastomers and fillers,can be used to upgrade the structure and properties of polymeric waste streams. This review discusses recent developments in the mechanical recycling of plastics, focusing on how to produce quality materials from waste streams and, thus, contribute to a sustainable management of resources and energy. [source] Molecular dynamics of the blood,testis barrier components during murine spermatogenesisMOLECULAR REPRODUCTION & DEVELOPMENT, Issue 7 2010Masataka Chihara The blood,testis barrier (BTB) separates the seminiferous epithelium into the adluminal and basal compartments. During murine spermatogenesis, preleptotene/leptotene spermatocytes migrate from the basal to the adluminal compartment through the BTB during stages VIII,IX. In the present study, we focused on the tight junction (TJ) molecules and analyzed their spatiotemporal expression during the murine seminiferous epithelial cycle. Structural analysis revealed that the principal components of the BTB, for example, claudin-3, claudin-11, occludin, and zonula occludens-1 (ZO-1), were localized at the basal and luminal sides of the preleptotene/leptotene spermatocytes during the migration stages (VIII,IX). Although we detected claudin-11, occludin, and ZO-1 throughout spermatogenesis, claudin-3 was only detected during stages VI,IX. Quantitative PCR using dissected seminiferous tubules from three stages (Early: II,VI, Middle: VII,VIII, Late: IX,I) clarified that the mRNA levels of TJ molecules were not correlated with the histoplanimetrical protein levels during spermatogenesis. Additionally, tubulobulbar complexes, considered to be involved in the internalization of TJ, were observed at the BTB site. Furthermore, a significant reduction in the mRNA levels of genes for the degradation of occludin (Itch) and endocytic recycling (Rab13) were observed during the Late and Middle stages, respectively. Therefore, we hypothesized that the lag between mRNA and protein expression of TJ molecules may be due to posttranslational modulation, for example, tubulobulbar complexes and endocytic recycling processes. In conclusion, these findings indicate that the integrity of the BTB is maintained throughout spermatogenesis, and the stage-specific localization of claudin-3 protein plays an important role in regulating BTB permeability. Mol. Reprod. Dev. 77: 630,639, 2010. © 2010 Wiley-Liss, Inc. [source] Nutrient transport within and between habitats through seed dispersal processes by woolly monkeys in north-western AmazoniaAMERICAN JOURNAL OF PRIMATOLOGY, Issue 11 2010Pablo R. Stevenson Abstract The contribution of vertebrate animals to nutrient cycling has proven to be important in various ecosystems. However, the role of large bodied primates in nutrient transport in neotropical forests is not well documented. Here, we assess the role of a population of woolly monkeys (Lagothrix lagothricha lugens) as vectors of nutrient movement through seed dispersal. We estimated total seed biomass transported by the population within and between two habitats (terra firme and flooded forests) at Tinigua Park, Colombia, and quantified potassium (K), phosphorus (P) and nitrogen (N) content in seeds of 20 plant species from both forests. Overall, the population transported an estimated minimum of 11.5 (±1.2 SD),g of potassium, 13.2 (±0.7),g of phosphorus and 34.3 (±0.1),g nitrogen, within 22.4 (±2.0),kg of seeds ha,1,y,1. Approximately 84% of all nutrients were deposited in the terra firme forest mostly through recycling processes, and also through translocation from the flooded forest. This type of translocation represents an important and high-quality route of transport since abiotic mechanisms do not usually move nutrients upwards, and since chemical tests show that seeds from flooded forests have comparatively higher nutrient contents. The overall contribution to nutrient movement by the population of woolly monkeys is significant because of the large amount of biomass transported, and the high phosphorus content of seeds. As a result, the phosphorus input generated by these monkeys is of the same order of magnitude as other abiotic mechanisms of nutrient transport such as atmospheric deposition and some weathering processes. Our results suggest that via seed dispersal processes, woolly monkey populations can contribute to nutrient movement in tropical forests, and may act as important nutrient input vectors in terra firme forests. Am. J. Primatol. 72:992,1003, 2010. © 2010 Wiley-Liss, Inc. [source] High-temperature sequestration of elemental mercury by noncarbon based sorbentsASIA-PACIFIC JOURNAL OF CHEMICAL ENGINEERING, Issue 2 2010Sung Jun Lee Abstract This work is concerned with sequestration of elemental Hg at high temperatures (900,1100 °C) on a sorbent that is mineral based, rather than carbon based. This sorbent consists of an intimate mixture of CaO, CaCO3, and Al2O3,2SiO2, and is manufactured in industrially relevant quantities (metric tons) from residues produced in paper recycling processes. In contrast to activated carbon (AC), this noncarbon based sorbent has special advantages in that, it can actually enhance fly ash utilization for cement manufacture, rather than diminish it, as is the case for AC. Disperse phase experiments have been conducted, using an externally heated quartz tube reactor, with sorbent feeding rates ranging from 1 to 6 g/h. Preliminary results indicate that Hg removal efficiency is sensitive to sorbent feed rates and to furnace temperature. The Hg removal percentage increased with both these variables. Two mechanisms come into play: an in-flight Hg sorption mechanism, and an Hg sorption mechanism related to sorbent deposits on the reactor wall. A maximum total (in-flight plus deposit-related) Hg removal efficiency of 83,90% was obtained at temperatures of 900,1100 °C. There was negligible sorption by either mechanism at temperatures below 600 °C. Results for the in-flight mechanism alone showed a maximum sorption efficiency at ,900 °C, whereas that on the reactor surface increased monotonically with temperature. This suggests that sorbent deactivation can occur in-flight at high temperatures, which is in agreement with other fixed bed results obtained in this laboratory. Deactivation was not apparent for the sorbent-related substance formed on the reactor wall. Raw and spent sorbents were analyzed by X-ray diffraction (XRD) and scanning electron microscopy with energy dispersive spectrophotometer (SEM-EDS) to identify the sorbent mineral transitions that seem to activate the process. The in-flight mechanisms appear to involve (1) activation of the sorbent, caused most probably by an internal solid,solid reaction, followed by (2) Hg sorption, and (3) possible deactivation, if the temperatures are too high for longer period. Reactor surface mechanisms still remain to be elucidated. 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