654 research outputs found

    Competitive adsorption of bile salts and milk protein in oil-in-water emulsions

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    The competitive adsorption of bile salts with milk proteins (whey protein concentrate (WPC) or sodium caseinate (SCN)) was studied in oil-in-water emulsions. The research confirmed previous findings that the degree of displacement of protein depends on the number of hydroxyl groups attached to the sterol ring of the bile salt, but also highlighted the importance of the presence (or absence) and nature of amino acid residues conjugated with the sterol ring. In general, decreasing the number of dihydroxy bile salts such as sodium deoxycholate (NaDC) displaced more protein from the oil droplet surface than trihydroxy bile salts such as sodium cholate (NaC). This is attributed to the greater hydrophobicity of the sterol ring of the NaDC. However, hydrophobicity is not the only factor that determines the ability of the bile salt to displace protein. If sodium taurocholate (NaTC) is used in the competitive adsorption experiments which contains a large charged hydrophilic sulphonate group attached to a taurine residue conjugated to a NaC molecule, the NaTC displaces much more protein from the emulsion droplet surface even though NaTC is less hydrophobic than NaC. A similar effect is seen with sodium glycodeoxycholate (NaGDC) when compared to NaDC. NaGDC is less hydrophobic than NaDC due to the conjugation of a glycine residue, but NaGDC is better at displacing protein from the oil-water interface. This observation is explained in terms of the greater steric hindrance that a conjugated bile salt (NaTC or NaGDC) experiences when it adsorbs to an oil-water interface. The charge amino acid group sits further into the aqueous side of the oil-droplet interface and disrupts the adsorbed protein layer to a greater extent than the non-conjugated bile salts. Another interesting feature of the competitive adsorption was the difference between degree of displacement for the different protein types SCN or WPC. For all bile salts SCN was significantly more resistant to displacement than WPC. The reason for this is not clear but may be due to either the greater surface activity of caseins, or to binding of bile salts to WPC or SCN proteins. To investigate further the adsorption of bile salt in emulsions the surface coverage of the bile salts was determined. Results indicated that NaC adsorb as a monomer over much of the concentration range used, whilst the other three bile salts adsorbed as micelles. The consequences of this for competitive displacement of protein are discussed. Finally, preliminary experiments were carried out to elucidate the effect of NaC concentration on lipase catalysed hydrolysis of the triglycerides in the emulsion droplets. The release of free fatty acids is observed to increase with increasing NaC concentration in the emulsion. This is discussed in relation to the effect of NaC on the WPC and SCN protein concentration at the droplet surface, and the likely effect of NaC micelles on the rate of lipase activit

    Spatiotemporal Control of Opioid Signaling and Behavior

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    SummaryOptogenetics is now a widely accepted tool for spatiotemporal manipulation of neuronal activity. However, a majority of optogenetic approaches use binary on/off control schemes. Here, we extend the optogenetic toolset by developing a neuromodulatory approach using a rationale-based design to generate a Gi-coupled, optically sensitive, mu-opioid-like receptor, which we term opto-MOR. We demonstrate that opto-MOR engages canonical mu-opioid signaling through inhibition of adenylyl cyclase, activation of MAPK and G protein-gated inward rectifying potassium (GIRK) channels and internalizes with kinetics similar to that of the mu-opioid receptor. To assess in vivo utility, we expressed a Cre-dependent viral opto-MOR in RMTg/VTA GABAergic neurons, which led to a real-time place preference. In contrast, expression of opto-MOR in GABAergic neurons of the ventral pallidum hedonic cold spot led to real-time place aversion. This tool has generalizable application for spatiotemporal control of opioid signaling and, furthermore, can be used broadly for mimicking endogenous neuronal inhibition pathways

    Reliability of Automated Biochemical Identification of Burkholderia pseudomallei Is Regionally Dependent

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    Misidentifications of Burkholderia pseudomallei as Burkholderia cepacia by Vitek 2 have occurred. Multidimensional scaling ordination of biochemical profiles of 217 Malaysian and Australian B. pseudomallei isolates found clustering of misidentified B. pseudomallei isolates from Malaysian Borneo. Specificity of B. pseudomallei identification in Vitek 2 and potentially other automated identification systems is regionally dependent

    Reading handwritten digits: a ZIP code recognition system

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    A neural network algorithm-based system that reads handwritten ZIP codes appearing on real US mail is described. The system uses a recognition-based segmenter, that is a hybrid of connected-components analysis (CCA), vertical cuts, and a neural network recognizer. Connected components that are single digits are handled by CCA. CCs that are combined or dissected digits are handled by the vertical-cut segmenter. The four main stages of processing are preprocessing, in which noise is removed and the digits are deslanted, CCA segmentation and recognition, vertical-cut-point estimation and segmentation, and directly lookup. The system was trained and tested on approximately 10000 images, five- and nine-digit ZIP code fields taken from real mail

    No Exit? Withdrawal Rights and the Law of Corporate Reorganizations

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    Bankruptcy scholarship is largely a debate about the comparative merits of a mandatory regime on one hand and bankruptcy by free design on the other. By the standard account, the current law of corporate reorganization is mandatory. Various rules that cannot be avoided ensure that investors’ actions are limited and they do not exercise their rights against specialized assets in a way that destroys the value of a business as a whole. These rules solve collective action problems and reduce the risk of bargaining failure. But there are costs to a mandatory regime. In particular, investors cannot design their rights to achieve optimal monitoring as they could in a system of bankruptcy by free design. This Article suggests that the academic debate has missed a fundamental feature of the law. Bankruptcy operates on legal entities, not on firms in the economic sense. For this reason, sophisticated investors do not face a mandatory regime at all. The ability of investors to place assets in separate entities gives them the ability to create specific withdrawal rights in the event the firm encounters financial distress. There is nothing mandatory about rules like the automatic stay when assets can be partitioned off into legal entities that are beyond the reach of the bankruptcy judge. Thus, by partitioning assets of one economic enterprise into different legal entities, investors can create a tailored bankruptcy regime. In this way, legal entities serve as building blocks that can be combined to create specific and varied but transparent investor withdrawal rights. This regime of tailored bankruptcy has been unrecognized and underappreciated and may be preferable to both mandatory and free design regimes. By allowing a limited number of investors to opt out of bankruptcy in a particular, discrete, and visible way, investors as a group may be able to both limit the risk of bargaining failure and at the same time enjoy the disciplining effect that a withdrawal right brings with it

    Prevalence and associated risk factors of malaria among adults in East Shewa Zone of Oromia Regional State, Ethiopia: a cross-sectional study

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    BACKGROUND: Malaria is one of the most important causes of morbidity and mortality in sub-Saharan Africa. The disease is prevalent in over 75% of the country's area making it the leading public health problems in the country. Information on the prevalence of malaria and its associated factors is vital to focus and improve malaria interventions. METHODS: A cross-sectional study was carried out from October to November 2012 in East Shewa zone of Oromia Regional State, Ethiopia. Adults aged 16 or more years with suspected malaria attending five health centers were eligible for the study. Logistic regression models were used to examine the effect of each independent variable on risk of subsequent diagnosis of malaria. RESULTS: Of 810 suspected adult malaria patients who participated in the study, 204 (25%) had microscopically confirmed malaria parasites. The dominant Plasmodium species were P. vivax (54%) and P. falciparum (45%), with mixed infection of both species in one patient. A positive microscopic result was significantly associated with being in the age group of 16 to 24 years [Adjusted Odds Ratio aOR 6.7; 95% CI: 2.3 to 19.5], 25 to 34 years [aOR 4.2; 95% CI: 1.4 to 12.4], and 35 to 44 years [aOR 3.7; 95% CI: 1.2-11.4] compared to 45 years or older; being treated at Meki health center [aOR 4.1; 95% CI: 2.4 to 7.1], being in Shashemene health center [aOR = 2.3; 95% CI: 1.5 to 4.5], and living in a rural area compared to an urban area [aOR 1.7; 95% CI: 1.1 to 2.6)]. CONCLUSION: Malaria is an important public health problem among adults in the study area with a predominance of P. vivax and P. falciparum infection. Thus, appropriate health interventions should be implemented to prevent and control the disease

    A bovine lymphosarcoma cell line infected with theileria annulata exhibits an irreversible reconfiguration of host cell gene expression

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    Theileria annulata, an intracellular parasite of bovine lymphoid cells, induces substantial phenotypic alterations to its host cell including continuous proliferation, cytoskeletal changes and resistance to apoptosis. While parasite induced modulation of host cell signal transduction pathways and NFÎșB activation are established, there remains considerable speculation on the complexities of the parasite directed control mechanisms that govern these radical changes to the host cell. Our objectives in this study were to provide a comprehensive analysis of the global changes to host cell gene expression with emphasis on those that result from direct intervention by the parasite. By using comparative microarray analysis of an uninfected bovine cell line and its Theileria infected counterpart, in conjunction with use of the specific parasitacidal agent, buparvaquone, we have identified a large number of host cell gene expression changes that result from parasite infection. Our results indicate that the viable parasite can irreversibly modify the transformed phenotype of a bovine cell line. Fifty percent of genes with altered expression failed to show a reversible response to parasite death, a possible contributing factor to initiation of host cell apoptosis. The genes that did show an early predicted response to loss of parasite viability highlighted a sub-group of genes that are likely to be under direct control by parasite infection. Network and pathway analysis demonstrated that this sub-group is significantly enriched for genes involved in regulation of chromatin modification and gene expression. The results provide evidence that the Theileria parasite has the regulatory capacity to generate widespread change to host cell gene expression in a complex and largely irreversible manner
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