351 research outputs found
Investigation of biomass and agricultural plastic co-pyrolysis: Effect on biochar yield and properties
Complete separation of mixed plastic and biomass waste is a technically difficult, laborious, expensive and time-consuming process. Hence, co-pyrolysis of these agricultural waste streams with low levels of plastic contamination presents a novel approach for the management of these plastic containing wastes, producing stable forms of carbon with potential use in environmental, agricultural and industrial applications. In this study, spent growing medium along with plastic growing bags, and bean crop residues along with mulching sheets were selected to assess how the presence of plastics would affect the characteristics of the biochars produced. These feedstocks were combined in mass ratios (of plastic in the biomass-plastic mixture) of 0, 0.25, 2.5, 5 and 10%. The resulting feedstock underwent slow pyrolysis in a fixed bed pyrolysis reactor at a temperature of 550 °C to ensure complete conversion of the plastic components of the feedstock. From the results obtained from pyrolysis, low ratios of plastic were found to have a positive impact on biochar yield, while high plastic ratios were found to have negative effect. Higher level of plastic in the feedstock have resulted peculiar functional groups in the biochar, including carboxylate anions, amides and aromatic groups. Biochars produced from spent growing medium along with plastic grow bags (GM biochars) showed no phytotoxic effect, irrespective of the concentration of plastic contamination in the feedstock. Biochars produced from bean crop residues along with mulching sheets (BM biochars) on the other hand showed high level of phytotoxicity (zero germination), irrespective of level of plastic contamination. After washing all BM biochar, very low phytotoxicity levels with no statistically significant effect of plastic contamination were observed, with the exception of 10BM that showed somewhat a reduced germination rate (93%). The results of this study will be beneficial for determining the tolerable level of plastic contamination in managing mixed agricultural waste biomass and to produce biochars suitable for environmental, agricultural and/or industrial applications
Arabidopsis hypocotyl adventitious root formation is suppressed by ABA signaling
Roots are composed of different root types and, in the dicotyledonous Arabidopsis, typically consist of a primary root that branches into lateral roots. Adventitious roots emerge from non-root tissue and are formed upon wounding or other types of abiotic stress. Here, we investigated adventitious root (AR) formation in Arabidopsis hypocotyls under conditions of altered abscisic acid (ABA) signaling. Exogenously applied ABA suppressed AR formation at 0.25 µM or higher doses. AR formation was less sensitive to the synthetic ABA analog pyrabactin (PB). However, PB was a more potent inhibitor at concentrations above 1 µM, suggesting that it was more selective in triggering a root inhibition response. Analysis of a series of phosphonamide and phosphonate pyrabactin analogs suggested that adventitious root formation and lateral root branching are differentially regulated by ABA signaling. ABA biosynthesis and signaling mutants affirmed a general inhibitory role of ABA and point to PYL1 and PYL2 as candidate ABA receptors that regulate AR inhibition
The Subsystems Approach to Genome Annotation and its Use in the Project to Annotate 1000 Genomes
The release of the 1000(th) complete microbial genome will occur in the next two to three years. In anticipation of this milestone, the Fellowship for Interpretation of Genomes (FIG) launched the Project to Annotate 1000 Genomes. The project is built around the principle that the key to improved accuracy in high-throughput annotation technology is to have experts annotate single subsystems over the complete collection of genomes, rather than having an annotation expert attempt to annotate all of the genes in a single genome. Using the subsystems approach, all of the genes implementing the subsystem are analyzed by an expert in that subsystem. An annotation environment was created where populated subsystems are curated and projected to new genomes. A portable notion of a populated subsystem was defined, and tools developed for exchanging and curating these objects. Tools were also developed to resolve conflicts between populated subsystems. The SEED is the first annotation environment that supports this model of annotation. Here, we describe the subsystem approach, and offer the first release of our growing library of populated subsystems. The initial release of data includes 180 177 distinct proteins with 2133 distinct functional roles. This data comes from 173 subsystems and 383 different organisms
An RNA-Binding Protein Secreted by a Bacterial Pathogen Modulates RIG-I Signaling.
RNA-binding proteins (RBPs) perform key cellular activities by controlling the function of bound RNAs. The widely held assumption that RBPs are strictly intracellular has been challenged by the discovery of secreted RBPs. However, extracellular RBPs have been described in eukaryotes, while secreted bacterial RBPs have not been reported. Here, we show that the bacterial pathogen Listeria monocytogenes secretes a small RBP that we named Zea. We show that Zea binds a subset of L. monocytogenes RNAs, causing their accumulation in the extracellular medium. Furthermore, during L. monocytogenes infection, Zea binds RIG-I, the non-self-RNA innate immunity sensor, potentiating interferon-β production. Mouse infection studies reveal that Zea affects L. monocytogenes virulence. Together, our results unveil that bacterial RNAs can be present extracellularly in association with RBPs, acting as "social RNAs" to trigger a host response during infection
Comparative genomics of 10 new Caenorhabditis species
Abstract The nematode Caenorhabditis elegans has been central to the understanding of metazoan biology. However, C. elegans is but one species among millions and the significance of this important model organism will only be fully revealed if it is placed in a rich evolutionary context. Global sampling efforts have led to the discovery of over 50 putative species from the genus Caenorhabditis, many of which await formal species description. Here, we present species descriptions for 10 new Caenorhabditis species. We also present draft genome sequences for nine of these new species, along with a transcriptome assembly for one. We exploit these whole‐genome data to reconstruct the Caenorhabditis phylogeny and use this phylogenetic tree to dissect the evolution of morphology in the genus. We reveal extensive variation in genome size and investigate the molecular processes that underlie this variation. We show unexpected complexity in the evolutionary history of key developmental pathway genes. These new species and the associated genomic resources will be essential in our attempts to understand the evolutionary origins of the C. elegans model
Strongly Reducing (Diarylamino)benzene-Based Covalent Organic Framework for Metal-Free Visible Light Photocatalytic H2O2 Generation
Photocatalytic reduction of molecular oxygen is a promising route toward sustainable production of hydrogen peroxide (H2O2). This challenging process requires photoactive semiconductors enabling solar energy driven generation and separation of electrons and holes with high charge transfer kinetics. Covalent organic frameworks (COFs) are an emerging class of photoactive semiconductors, tunable at a molecular level for high charge carrier generation and transfer. Herein, we report two newly designed two-dimensional COFs based on a (diarylamino)benzene linker that form a Kagome (kgm) lattice and show strong visible light absorption. Their high crystallinity and large surface areas (up to 1165 m(2)center dot g(-1)) allow efficient charge transfer and diffusion. The diarylamine (donor) unit promotes strong reduction properties, enabling these COFs to efficiently reduce oxygen to form H2O2. Overall, the use of a metal-free, recyclable photocatalytic system allows efficient photocatalytic solar transformations.DFG, 390540038, EXC 2008: Unifying Systems in Catalysis "UniSysCat"EC/H2020/665501/EU/[PEGASUS]², giving wings to your career./PEGASUS-2EC/H2020/834134/EU/Water Forced in Hydrophobic Nano-Confinement: Tunable Solvent System/WATUSOEC/H2020/647755/EU/First principle molecular dynamics simulations for complex chemical transformations in nanoporous materials/DYNPO
Repetition Enhancement for Frequency-Modulated but Not Unmodulated Sounds: A Human MEG Study
BACKGROUND: Decoding of frequency-modulated (FM) sounds is essential for phoneme identification. This study investigates selectivity to FM direction in the human auditory system. METHODOLOGY/PRINCIPAL FINDINGS: Magnetoencephalography was recorded in 10 adults during a two-tone adaptation paradigm with a 200-ms interstimulus-interval. Stimuli were pairs of either same or different frequency modulation direction. To control that FM repetition effects cannot be accounted for by their on- and offset properties, we additionally assessed responses to pairs of unmodulated tones with either same or different frequency composition. For the FM sweeps, N1m event-related magnetic field components were found at 103 and 130 ms after onset of the first (S1) and second stimulus (S2), respectively. This was followed by a sustained component starting at about 200 ms after S2. The sustained response was significantly stronger for stimulation with the same compared to different FM direction. This effect was not observed for the non-modulated control stimuli. CONCLUSIONS/SIGNIFICANCE: Low-level processing of FM sounds was characterized by repetition enhancement to stimulus pairs with same versus different FM directions. This effect was FM-specific; it did not occur for unmodulated tones. The present findings may reflect specific interactions between frequency separation and temporal distance in the processing of consecutive FM sweeps
Decreased motivation in the use of insecticide-treated nets in a malaria endemic area in Burkina Faso
<p>Abstract</p> <p>Background</p> <p>The use of insecticide-treated nets (ITN) is an important tool in the Roll Back Malaria (RBM) strategy. For ITNs to be effective they need to be used correctly. Previous studies have shown that many factors, such as wealth, access to health care, education, ethnicity and gender, determine the ownership and use of ITNs. Some studies showed that free distribution and public awareness campaigns increased the rate of use. However, there have been no evaluations of the short- and long-term impact of such motivation campaigns. A study carried out in a malaria endemic area in south-western Burkina Faso indicated that this increased use declined after several months. The reasons were a combination of the community representation of malaria, the perception of the effectiveness and usefulness of ITNs and also the manner in which households are organized by day and by night.</p> <p>Methods</p> <p>PermaNet 2.0<sup>® </sup>and Olyset<sup>® </sup>were distributed in 455 compounds at the beginning of the rainy season. The community was educated on the effectiveness of nets in reducing malaria and on how to use them. To assess motivation, qualitative tools were used: one hundred people were interviewed, two hundred houses were observed directly and two houses were monitored monthly throughout one year.</p> <p>Results</p> <p>The motivation for the use of bednets decreased after less than a year. Inhabitants' conception of malaria and the inconvenience of using bednets in small houses were the major reasons. Acceptance that ITNs were useful in reducing malaria was moderated by the fact that mosquitoes were considered to be only one of several factors which caused malaria. The appropriate and routine use of ITNs was adversely affected by the functional organization of the houses, which changed as between day and night. Bednets were not used when the perceived benefits of reduction in mosquito nuisance and of malaria were considered not to be worth the inconvenience of daily use.</p> <p>Conclusion</p> <p>In order to bridge the gap between possession and use of bednets, concerted efforts are required to change behaviour by providing accurate information, most particularly by convincing people that mosquitoes are the only source of malaria, whilst recognising that there are other diseases with similar symptoms, caused in other ways. The medical message must underline the seriousness of malaria and the presence of the malaria vector in the dry season as well as the wet, in order to encourage the use of bednets whenever transmission can occur. Communities would benefit from impregnated bednets and other vector control measures being better adapted to their homes, thus reducing the inconvenience of their use.</p
Absorbing customer knowledge: how customer involvement enables service design success
Customers are a knowledge resource outside of the firm that can be utilized for new service success by involving them in the design process. However, existing research on the impact of customer involvement (CI) is inconclusive. Knowledge about customers’ needs and on how best to serve these needs (articulated in the service concept) is best obtained from customers themselves. However, codesign runs the risk of losing control of the service concept. This research argues that of the processes of external knowledge, acquisition (via CI), customer knowledge assimilation, and concept transformation form a capability that enables the firm to exploit customer knowledge in the form of a successful new service. Data from a survey of 126 new service projects show that the impact of CI on new service success is fully mediated by customer knowledge assimilation (the deep understanding of customers’ latent needs) and concept transformation (the modification of the service concept due to customer insights). However, its impact is more nuanced. CI exhibits an “∩”-shaped relationship with transformation, indicating there is a limit to the beneficial effect of CI. Its relationship with assimilation is “U” shaped, suggesting a problem with cognitive inertia where initial learnings are ignored. Customer knowledge assimilation directly impacts success, while concept transformation only helps success in the presence of resource slack. An evolving new service design is only beneficial if the firm has the flexibility to adapt to change
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