1,353 research outputs found

    Creating Future Agricultural Leaders Within Native Nations of Oklahoma

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    This research looks at the agricultural history and current agricultural systems of four Oklahoma-based Native nations and the College of the Muscogee Nation. The study also specifically looks at the development of future agricultural leaders

    Credit-constrained in risky activities? The determinants of the capital stocks of micro and small firms in Western Africa

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    Micro and small enterprises (MSEs) in developing countries are typically considered to be severely credit constrained. Additionally, high business risks may partly explain why the capital stocks of MSEs remain low. This article analyzes the determinants of the capital stocks of MSEs in poor economies focusing on credit constraints and risk. The analysis is based on a unique, albeit cross‐sectional but backward‐looking, micro data set on MSEs covering the economic capitals of seven West‐African countries. The main result is that capital market imperfections indeed seem to explain an important part of the variation in capital stocks in the early lifetime of MSEs. Furthermore, the analyses show that risk plays a key role in capital accumulation. Risk‐averse individuals seem to adjust their initially low capital stocks upwards when enterprises grow older. MSEs in risky activities owned by wealthy individuals even seem to over‐invest when they start their business and subsequently adjust capital stocks downwards. As other firms simultaneously suffer from capital shortages, such behaviour may imply large inefficiencies

    Credit‐constrained in risky activities? The determinants of the capital stocks of micro and mall firms in Western Africa

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    Micro and small enterprises (MSEs) in developing countries are typically considered to be severely credit constrained. Additionally, high business risks may partly explain why the capital stocks of MSEs remain low. This article analyzes the determinants of the capital stocks of MSEs in poor economies focusing on credit constraints and risk. The analysis is based on a unique, albeit cross-sectional but backward‐looking, micro data set on MSEs covering the economic capitals of seven West‐African countries. The main result is that capital market imperfections indeed seem to explain an important part of the variation in capital stocks in the early lifetime of MSEs. Furthermore, the analyses show that risk plays a key role in capital accumulation. Risk-averse individuals seem to adjust their initially low capital stocks upwards when enterprises grow older. MSEs in risky activities owned by wealthy individuals even seem to over-invest when they start their business and subsequently adjust capital stocks downwards. As other firms simultaneously suffer from capital shortages, such behavior may imply large inefficiencies

    Oxidative cytotoxic agent withaferin A resensitizes temozolomide-resistant glioblastomas via MGMT depletion and induces apoptosis through Akt/mTOR pathway inhibitory modulation

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    Temozolomide (TMZ) has remained the chemotherapy of choice in patients with glioblastoma multiforme (GBM) primarily due to the lack of more effective drugs. Tumors, however, quickly develop resistance to this line of treatment creating a critical need for alternative approaches and strategies to resensitize the cells. Withaferin A (WA), a steroidal lactone derived from several genera of the Solanaceae plant family has previously demonstrated potent anti-cancer activity in multiple tumor models. Here, we examine the effects of WA against TMZ-resistant GBM cells as a monotherapy and in combination with TMZ. WA prevented GBM cell proliferation by dose-dependent G2/M cell cycle arrest and cell death through both intrinsic and extrinsic apoptotic pathways. This effect correlated with depletion of principle proteins of the Akt/mTOR and MAPK survival and proliferation pathways with diminished phosphorylation of Akt, mTOR, and p70 S6K but compensatory activation of ERK1/2. Depletion of tyrosine kinase cell surface receptors c-Met, EGFR, and Her2 was also observed. WA demonstrated induction of N-acetyl-L-cysteine-repressible oxidative stress as measured directly and through a subsequent heat shock response with HSP32 and HSP70 upregulation and decreased HSF1. Finally, pretreatment of TMZ-resistant GBM cells with WA was associated with O6-methylguanine-DNA methyltransferase (MGMT) depletion which potentiated TMZ-mediated MGMT degradation. Combination treatment with both WA and TMZ resulted in resensitization of MGMT-mediated TMZ-resistance but not resistance through mismatch repair mutations. These studies suggest great clinical potential for the utilization of WA in TMZ-resistant GBM as both a monotherapy and a resensitizer in combination with the standard chemotherapeutic agent TMZ

    l-Acetyl-carnitine in Patients with Carpal Tunnel Syndrome: Effects on Nerve Protection, Hand Function and Pain

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    Background and Aim: l-Acetyl-carnitine (LAC) exerts an energetic effect on nerves and muscles. Recently, preclinical experiments have demonstrated a central anti-nociceptive action. Objective: Our objective was to assess the effects of LAC on neuroprotection, pain, and function in carpal tunnel syndrome (CTS), a very frequent chronic compressive neuropathy. Methods: In a multicentre, examiner-blinded, clinical and neurophysiological 4-month study, we enrolled 82 patients and examined 120 hands with CTS of mild to moderate severity. Patients were assessed at baseline and 10, 60 and 120\uc2 days after treatment with LAC 500\uc2 mg twice daily (BID). All patients underwent a conduction study of the median nerve, the Boston Carpal Tunnel Questionnaire (BCTQ) and the Neuropathic Pain Symptom Inventory (NPSI). The primary endpoint was the sensory conduction velocity (SCV) of the median nerve. Results: The primary endpoint was met, with significant improvement of the SCV (P\uc2&nbsp

    Adaptive evolution of Toll-like receptor 5 in domesticated mammals

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    <p>Abstract</p> <p>Background</p> <p>Previous studies have proposed that mammalian toll like receptors (TLRs) have evolved under diversifying selection due to their role in pathogen detection. To determine if this is the case, we examined the extent of adaptive evolution in the TLR5 gene in both individual species and defined clades of the mammalia.</p> <p>Results</p> <p>In support of previous studies, we find evidence of adaptive evolution of mammalian TLR5. However, we also show that TLR5 genes of domestic livestock have a concentration of single nucleotide polymorphisms suggesting a specific signature of adaptation. Using codon models of evolution we have identified a concentration of rapidly evolving codons within the TLR5 extracellular domain a site of interaction between host and the bacterial surface protein flagellin.</p> <p>Conclusions</p> <p>The results suggest that interactions between pathogen and host may be driving adaptive change in TLR5 by competition between species. In support of this, we have identified single nucleotide polymorphisms (SNP) in sheep and cattle TLR5 genes that are co-localised and co-incident with the predicted adaptive codons suggesting that adaptation in this region of the TLR5 gene is on-going in domestic species.</p

    Efeito da fertilização precoce e roçada sobre o desenvolvimento e antecipação do ciclo de pastejo hibernal de pastagens consorciadas de hemartria e Azevém BRS Ponteio.

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    O objetivo do trabalho foi avaliar o desenvolvimento da pastagem consorciada de hemarthria e azevém BRS Ponteio (presente no banco de sementes do solo), submetida a dois fatores: adubação e roçada.Fernando Flores Cardoso, editor técnico

    Molecular evolution of bovine Toll-like receptor 2 suggests substitutions of functional relevance

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    <p>Abstract</p> <p>Background</p> <p>There is accumulating evidence that polymorphism in Toll-like receptor (<it>TLR) </it>genes might be associated with disease resistance or susceptibility traits in livestock. Polymorphic sites affecting TLR function should exhibit signatures of positive selection, identified as a high ratio of non-synonymous to synonymous nucleotide substitutions (ω). Phylogeny based models of codon substitution based on estimates of ω for each amino acid position can therefore offer a valuable tool to predict sites of functional relevance. We have used this approach to identify such polymorphic sites within the bovine <it>TLR2 </it>genes from ten <it>Bos indicus </it>and <it>Bos taurus </it>cattle breeds. By analysing <it>TLR2 </it>gene phylogeny in a set of mammalian species and a subset of ruminant species we have estimated the selective pressure on individual sites and domains and identified polymorphisms at sites of putative functional importance.</p> <p>Results</p> <p>The ω were highest in the mammalian TLR2 domains thought to be responsible for ligand binding and lowest in regions responsible for heterodimerisation with other TLR-related molecules. Several positively-selected sites were detected in or around ligand-binding domains. However a comparison of the ruminant subset of <it>TLR2 </it>sequences with the whole mammalian set of sequences revealed that there has been less selective pressure among ruminants than in mammals as a whole. This suggests that there have been functional changes during ruminant evolution. Twenty newly-discovered non-synonymous polymorphic sites were identified in cattle. Three of them were localised at positions shaped by positive selection in the ruminant dataset (Leu227Phe, His305Pro, His326Gln) and in domains involved in the recognition of ligands. His326Gln is of particular interest as it consists of an exchange of differentially-charged amino acids at a position which has previously been shown to be crucial for ligand binding in human TLR2.</p> <p>Conclusion</p> <p>Within bovine TLR2, polymorphisms at amino acid positions 227, 305 and 326 map to functionally important sites of TLR2 and should be considered as candidate SNPs for immune related traits in cattle. A final proof of their functional relevance requires further studies to determine their functional effect on the immune response after stimulation with relevant ligands and/or their association with immune related traits in animals.</p
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