560 research outputs found

    Paired aluminum sites in zeolite catalysts enhance aromatics production

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    In this issue of Chem Catalysis, Ruiz-Martínez and co-workers investigate the effect of aluminum (Al) proximity and distribution on acid-catalyzed reactions in zeolites. They find that Al enrichment near the external surface results in paired acid sites that exhibit enhanced activity for aromatics formation

    Silica-Based materials as catalysts or supports in solvent-free organic reactions

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    This chapter summarizes recent developments in solvent-free organic synthesis. In particular, the chapter focuses on the reactions conducted under neat conditions and in the presence of silica-based reagents or catalysts. The chapter describes the synthesis of those materials and salient features that are responsible for the enhanced reaction rates and greater selectivity. The discussion demonstrates that silica-based solids can be used to carry out a wide range of reactions and the approach can prove beneficial, leading to no solvent waste, in line with modern green chemistry metrics

    Sustainable upgrading of glycerol into glycidol and its derivatives under continuous-flow conditions

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    This study presents a continuous-flow process for the valorization of glycerol, a byproduct of the biofuel industry, into glycidol and its derivatives. The method ensures safety and allows for easy production of glycidol on a gram scale, even in the presence of hazardous substances such as hydrogen chloride and acetic acid. Moreover, this continuous-flow method can be easily integrated with downstream synthetic steps to produce value-added derivatives, which have potential applications in the fields of medicinal and polymer chemistry. The comprehensive evaluation of sustainability metrics, encompassing green indicators, a techno-economic analysis, and a life cycle assessment, substantiates the environmental benefits of the technology, and showed that the method is environmentally friendly and has the potential to enhance efficiency, safety, and sustainability in industrial processes

    Feeding dendritic cells with tumor antigens: self-service buffet or Ă  la carte?

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    Adoptive transfer of autologous dendritic cells (DC) presenting tumor-associated antigens initiate and sustain an immune response which eradicate murine malignancies. Based on these observations, several clinical trials are in progress testing safety and efficacy with encouraging preliminary reports. In these approaches, ex vivo incubation of DC with a source of tumor antigens is required to load the relevant antigenic epitopes on the adequate antigen presenting molecules. Recent data show that in some instances exogenous DC artificially injected into malignant tissue or endogenous DC attracted to the tumor nodule by means of gene transfer of GM-CSF and CD40L into malignant cells result in efficacious antitumor immunity. In the case of intratumoral injection of DC the procedure is curative only if DC had been genetically engineered to produce IL-12, IL-6 or to express CD40L. Evidence has been obtained showing that intratumoral DC can capture and process tumor antigens to be presented to T-lymphocytes. Although the exact mechanisms of tumor antigen acquisition by DC are still unclear, available data suggest a role for heat shock proteins released from dying malignant cells and for the internalization of tumor-derived apoptotic bodies. Roles for tumor necrosis versus apoptosis are discussed in light of the 'danger theory'

    The Hymenoptera Genome Database

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    The Hymenoptera Genome Database (HGD) is an informatics resource supporting genomics of hymenopteran insect species. This relational database implements open-source software and components providing access to curated data contributed by an extensive, active research community. HGD includes the genome sequences and annotation data of honey bee _Apis mellifera_ and its pathogens ("http://BeeBase.org":BeeBase.org) the parasitoid wasp _Nasonia vitripennis_ ("http://NasoniaBase.org":NasoniaBase.org) and a portal to the genomes of six species of ants. Together, these species cover approximately 200 MY in the phylogeny of Hymenoptera, allowing to leverage genetic, genome sequence, and gene expression data, as well as the biological knowledge of related model organisms. The availability of resources across an order greatly facilitates comparative genomics and enhances our understanding of the biology of agriculturally important Hymenoptera species through genomics. HGD has supported research contributions from an extensive community from almost 80 institutions in 14 countries. Community annotation efforts are made possible thanks to a remote connection to a Chado database by Apollo Genome Annotation client software. Curated data at HGD includes predicted and annotated gene sets supported with evidence tracks such as ESTs/cDNAs, small RNA sequences and GC composition domains. Data at HGD can be queried using genome browsers and / or BLAST/PSI-BLAST servers, and it may also be downloaded to perform local searches. We encourage the public to access and contribute data to HGD at "http://HymenopteraGenome.org":HymenopteraGenome.org.

This poster contains material included in an article accepted for publication in Nucl. Acids Res.©: 2011. The Database Issue. Published by Oxford University Press

    Interfacing single-atom catalysis with continuous-flow organic electrosynthesis

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    The global warming crisis has sparked a series of environmentally cautious trends in chemistry, allowing us to rethink the way we conduct our synthesis, and to incorporate more earth-abundant materials in our catalyst design. “Single-atom catalysis” has recently appeared on the catalytic spectrum, and has truly merged the benefits that homogeneous and heterogeneous analogues have to offer. Further still, the possibility to activate these catalysts by means of a suitable electric potential could pave the way for a true integration of diverse synthetic methodologies and renewable electricity. Despite their esteemed benefits, single-atom electrocatalysts are still limited to the energy sector (hydrogen evolution reaction, oxygen reduction, etc.) and numerous examples in the literature still invoke the use of precious metals (Pd, Pt, Ir, etc.). Additionally, batch electroreactors are employed, which limit the intensification of such processes. It is of paramount importance that the field continues to grow in a more sustainable direction, seeking new ventures into the space of organic electrosynthesis and flow electroreactor technologies. In this piece, we discuss some of the progress being made with earth abundant homogeneous and heterogeneous electrocatalysts and flow electrochemistry, within the context of organic electrosynthesis, and highlight the prospects of alternatively utilizing single-atom catalysts for such applications

    A supply chain approach to meat goat industry development

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    The Victorian goat meat industry is a significant contributor to export earnings, which is derived largely from the harvest of feral goats. The potential for exports of farmed goat meat into Asian product markets is being developed in a supply chain approach with producers, processors, exporters and Asian importers. Producers have been networked in four locations to improve supply capability and participate in production and economic benchmarking. In the absence of an existing market for premium farmed goat meat, a larger group of producers are cooperating with a marketer to develop a niche market in the Asian food service sector. This presents a challenge to the group in developing commercial relationships and playing a role in the marketing of their goat meat

    Facile Low-Temperature synthesis of novel carbon nitrides for efficient conversion of carbon dioxide into Value-Added chemicals

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    The interest in using carbon nitrides (CN) for CO2 conversion has stimulated extensive research on CN synthesis. Herein, we report the synthesis of two novel CN materials using low-cost commercially available precursors at low temperatures in a short duration of time. Two CN materials, one derived from 5-amino tetrazole (named 4NZ-CN) and the other derived from 3, 5-diamino-1, 2, 4-triazole (named 3NZ-CN) precursors, are prepared by refluxing these precursors for 2 h at 100 °C. 4NZ-CN and 3NZ-CN catalysts show higher surface areas (55.80 and 52.00 m2 g−1) and more basic sites (10.05 and 5.65 mmol g−1) than the conventional graphitic carbon nitride (g-C3N4) derived from melamine, for which the corresponding values are 9.20 m2 g−1 and 0.62 mmol g−1, respectively. In addition, both CN exhibit a 3-fold higher catalytic activity for CO2 cycloaddition to epoxides than g-C3N4. The structure−activity relationship was ascertained using a combination of experimental and computational studies, and a catalytic mechanism was proposed. This work provides a facile strategy for the synthesis of novel CN materials at relatively low temperatures, and the developed catalysts show remarkable performance in the conversion of CO2 to value-added chemicals
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