5,794 research outputs found

    Energy input and output of a rural village in China - the cas of the "Beijing Man village" /District of Beijing

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    The rapid development of the economy has created an increasing demand for energy in China. The limited resources of fossil energy are a risk for the development of China. Sustainable agriculture like organic farming (Green AAA in China) with biomass energy - as done in developed countries like Germany - is an option to reduce these risks. In China, agriculture is not energy efficient, and the intensive farming is not sustainable. The scientific challenge is to develop sustainable farming systems which can fulfill national food security, food safety and considerable renewable energy production without harming the environment, and are acceptable to the people and the economy. The protection and intelligent utilization of resources is the core of rural village development. To explore the potential of recent Chinese agriculture for the development towards a multi-functional farm for food and energy production, a village in the adjacent area of Beijing has been selected: the “Beijing Man village”. About 1,900 people live in the village and 140 hectares of the 240 hectare total land are available for farming. The major agricultural activity is pork production (capacity of 10,000 pigs per year) and dairy farming (40 dairy cows). In 2004, the energy input and output of this village was evaluated and taken as a basis for a model of sustainable farming for food and biogas production. The study explored that the gross energy production from crops in the “Beijing man village” was about 19,103 GJ/year. It was obvious that the crop production was not sufficient for the feed demand of the animal husbandry (pigs and cows). 60% of the corn used as feed stuff was purchased on the market. The reason was, that the purchasing of corn was cheaper than the own production. The low competitive crop production due to the low efficiency resulted in the decrease of cultivated crop land from 140 ha to 80 ha in the past four years (two harvests per year). On the other hand, there was much more manure produced as suitable and applicable for crop production. Therefore manure was exposed in open air in a pond like waste. This is risky for public hazards like ground water contamination and zoonosis diseases. Therefore the farming system is not sustainable, risky and not efficient. There is a potential of the optimization of the cropping and animal husbandry interaction as well as the development of renewable energy production in the village. The main development chains are the improvement of the energy efficiency of crop production, the reduction of animal husbandry to a sustainable animal-land-ratio and the introduction of biogas production with manure and cropping by-products

    Physical mapping of a powdery mildew resistance related gene Hv-S/TPK by FISH with a TAC clone in wheat

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    Dissertação de mestrado integrado em Medicina (Hematologia), apresentado á Faculdade de Medicina da Universidade de Coimbra.A Policitemia Vera (PV) é uma doença clonal de etiologia desconhecida, na maior parte dos casos, que envolve a célula estaminal progenitora hematopoiética multipotencial. É uma neoplasia mieloproliferativa crónica (NMP) que se caracteriza pela expansão das três linhas celulares hematopoiéticas: eritróide, granulocítica e megacariocítica, com predomínio da primeira, de modo independente dos mecanismos normais de regulação da eritropoiese. Além disso, as células têm aspecto morfológico normal, a fibrose medular é pouco significativa e os níveis de eritropoietina (Epo) são habitualmente normais a baixos. Além da hipercelularidade medular com sobreprodução de uma ou de todas as linhas celulares, a doença cursa com hematopoiese extramedular, hiperviscosidade, propensão para complicações como trombose ou hemorragia e risco de desenvolvimento de mielofibrose ou transformação em leucemia aguda. A descrição relativamente recente da associação de uma mutação no gene JAK2, localizado no cromosoma 9p24, com as doenças mieloproliferativas clássicas negativas para BCR-ABL, como a PV, veio permitir avanços significativos na compreensão da patofisiologia deste grupo de doenças hematológicas. A mutação provoca uma alteração do aminoácido V (valina) para F (fenilalanina) na posição 617 (JAK2V617F). De acordo com os dados publicados, a frequência da detecção da mutação JAK2V617F em doentes com PV é de cerca de 95%. A proteína JAK2 é uma tirosina cinase citoplasmática, que se encontra associada ao domínio intracelular dos receptores de citocinas (como a Epo e trombopoietina - Tpo), e de factores de crescimento, essenciais para a função destes receptores. A mutação da JAK2 conduz à activação constitutiva dos receptores, independente da ligação à respectiva citocina e/ou hipersensibilidade a factores de crescimento, com consequente activação de múltiplas vias de sinalização intracelulares como a JAK/STAT (Janus Kinase/Signal Transductor and activator of transcription), a PI3K (fosfatidilinositol 3 cinase) e a MAPK (proteína cinase activadora de mitose), envolvidas na transformação e proliferação dos progenitores hematopoiéticos. Por outro lado, as células evidenciam alteração na diferenciação terminal e resistência à apoptose in vitro que poderá estar relacionada com o aumento da expressão da proteína anti-apoptótica Bcl-XL. Além dos avanços no diagnóstico, a detecção da mutação JAK2V617F tem contribuido para melhorar a classificação e a terapêutica dos doentes com PV. Deste modo, o conhecimento dos mecanismos moleculares envolvidos na PV tem levado os investigadores à descoberta de novos fármacos dirigidos ao defeito molecular, permitindo novas abordagem terapêuticas mais eficazes e provavelmente de menor toxicidade. Este trabalho procura fazer uma revisão sobre o actual conhecimento da caracterização molecular e clínica da PV e quais as suas implicações no diagnóstico e abordagem terapêutica desta NMP.Polycythemia Vera (PV) is a clonal disease of unknown etiology, which often involves the pluripotential hematopoietic stem cell. This disease integrates the family of chronic myeloproliferative neoplasm (MPN) and is characterized by the growth of the three hematopoietic celular lineages: granulocytic, megakaryocytic and erythroid, with predominance of the last one and regardless the normal mechanisms of erythropoiesis regulation. Moreover, cells have normal morphological aspect, bone marrow shows slight fibrosis and the levels of erythropoietin (Epo) usually vary from normal to low. Besides marrow hypercellularity with overproduction of one or all the celular lineages, the disease courses with extramedullary hematopoiesis, hyperviscosity, leading to complications such as thrombosis or bleeding and risk of transformation to myelofibrosis or acute leukemia. Recently it has been described the association between the mutation in the JAK2 gene, located on chromosome 9p24, with the classic myeloproliferative disorders BCR-ABL negative, such as PV, which has brought significant advances in the understanding of the pathophysiology of this group of hematologic malignancies. The mutation causes a change of amino acid V (valine) to F (phenylalanine) at position 617 (JAK2V617F). According to published data, the frequency of JAK2V617F mutation detected in patients with PV is about 95%. JAK2 protein is a cytoplasmic tyrosine kinase, which is associated to the intracelular domain of cytokine receptors, such as Epo and thrombopoietin (Tpo), and growth factors which are essential to the function of these receptors. JAK2 mutation leads to the constitutive receptors activation, independent of connection to their cytokine and / or hypersensitivity to growth factors, with consequent activation of multiple intracellular signaling pathways such as JAK / STAT (Janus Kinase / Signal transducer and transcription activator), the PI3K (phosphatidylinositol 3 kinase) and MAPK (Mitogen-activated protein), involved in the transformation and proliferation of hematopoietic progenitors. Moreover, the cells show changes in terminal differentiation and resistance to in vitro apoptosis which is possibly related to the increasing expression of anti-apoptotic protein Bcl-XL. In addition to the advances in diagnosis, detection of JAK2V617F mutation has contributed to the improvement of classification and treatment in patients with PV. Thus, knowledge of the molecular mechanisms involved in PV has led investigators to the discovery of new drugs targeting molecular defects, allowing new therapeutic approach more efficient and probably less toxic. The aim of this article is to review the current knowledge of clinical and molecular characterization of PV, and its implications on the diagnosis and therapeutic approach of this myeloproliferative disorder

    MicroRNA-210 and endoplasmic reticulum chaperones in the regulation of chemoresistance in glioblastoma

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    Glioblastoma multiforme (GBM) is the commonest primary brain tumour in adults characterized by relentless recurrence due to resistance towards the standard chemotherapeutic agent temozolomide (TMZ). Prolyl 4-hydroxylase, beta polypeptide (P4HB), an endoplasmic reticulum (ER) chaperone, is known to be upregulated in TMZ-resistant GBM cells. MicroRNAs (miRNAs) are non-protein-coding transcripts that may play important roles in GBM chemoresistance. We surmised that miRNA dysregulations may contribute to P4HB upregulation, hence chemoresistance.We found that miRNA-210 (miR-210) was P4HB-targeting and was highly downregulated in TMZ-resistant GBM cells. Forced overexpression of miR-210 led to P4HB downregulation and a reduction in TMZ-resistance. A reciprocal relationship between their expressions was also verified in clinical glioma specimens. Our study is the first to demonstrate a potential link between miR-210 and ER chaperone in determining chemosensitivity in GBM. The findings have important translational implications in suggesting new directions of future studies.published_or_final_versio

    jMOTU and Taxonerator: Turning DNA Barcode Sequences into Annotated Operational Taxonomic Units

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    BACKGROUND: DNA barcoding and other DNA sequence-based techniques for investigating and estimating biodiversity require explicit methods for associating individual sequences with taxa, as it is at the taxon level that biodiversity is assessed. For many projects, the bioinformatic analyses required pose problems for laboratories whose prime expertise is not in bioinformatics. User-friendly tools are required for both clustering sequences into molecular operational taxonomic units (MOTU) and for associating these MOTU with known organismal taxonomies. RESULTS: Here we present jMOTU, a Java program for the analysis of DNA barcode datasets that uses an explicit, determinate algorithm to define MOTU. We demonstrate its usefulness for both individual specimen-based Sanger sequencing surveys and bulk-environment metagenetic surveys using long-read next-generation sequencing data. jMOTU is driven through a graphical user interface, and can analyse tens of thousands of sequences in a short time on a desktop computer. A companion program, Taxonerator, that adds traditional taxonomic annotation to MOTU, is also presented. Clustering and taxonomic annotation data are stored in a relational database, and are thus amenable to subsequent data mining and web presentation. CONCLUSIONS: jMOTU efficiently and robustly identifies the molecular taxa present in survey datasets, and Taxonerator decorates the MOTU with putative identifications. jMOTU and Taxonerator are freely available from http://www.nematodes.org/

    Deformation of the Fermi surface in the extended Hubbard model

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    The deformation of the Fermi surface induced by Coulomb interactions is investigated in the t-t'-Hubbard model. The interplay of the local U and extended V interactions is analyzed. It is found that exchange interactions V enhance small anisotropies producing deformations of the Fermi surface which break the point group symmetry of the square lattice at the Van Hove filling. This Pomeranchuck instability competes with ferromagnetism and is suppressed at a critical value of U(V). The interaction V renormalizes the t' parameter to smaller values what favours nesting. It also induces changes on the topology of the Fermi surface which can go from hole to electron-like what may explain recent ARPES experiments.Comment: 5 pages, 4 ps figure

    How the other half lives: CRISPR-Cas's influence on bacteriophages

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    CRISPR-Cas is a genetic adaptive immune system unique to prokaryotic cells used to combat phage and plasmid threats. The host cell adapts by incorporating DNA sequences from invading phages or plasmids into its CRISPR locus as spacers. These spacers are expressed as mobile surveillance RNAs that direct CRISPR-associated (Cas) proteins to protect against subsequent attack by the same phages or plasmids. The threat from mobile genetic elements inevitably shapes the CRISPR loci of archaea and bacteria, and simultaneously the CRISPR-Cas immune system drives evolution of these invaders. Here we highlight our recent work, as well as that of others, that seeks to understand phage mechanisms of CRISPR-Cas evasion and conditions for population coexistence of phages with CRISPR-protected prokaryotes.Comment: 24 pages, 8 figure
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