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  • 1
    Language: English
    In: Analytical chemistry, 15 June 2010, Vol.82(12), pp.5169-75
    Description: A multiscaled electrochemical probe is presented for Scanning Electrochemical Microscopy (SECM) experiments. It is fabricated by wet chemical etching followed by sputter-coating of an ordered optical fiber bundle. Owing to the optical fiber bundle preparation, the global electrode may present different shapes. After the chemical etching step, each one of these shapes is conserved and finally decorated with 6000 nanotips. Numerical simulations and approach curves are used to study the probe properties and the influence of the global shape and of the nanotips. The numerical simulations show that the approach curves do not depend on the shape of the electrode but rather on the total height of the protuberance of its electroactive part. Such new SECM probes are then used to pattern a Teflon surface. Indeed, by controlling the time scale of the applied potential pulses, the thickness of the reaction layer is confined at each nanotip, and the nanotip pattern is electrochemically transferred onto the non-conductive surface. Both scales (i.e., global electrode shape and nanotip array) thus show distinct and complementary features for positioning the probe and for the subsequent electrochemical patterning.
    Keywords: Chemical Microscopy -- Methods ; Electrochemical Analysis -- Methods ; Scanning Microscopy -- Methods ; Lithography (Circuit fabrication) -- Methods ; Electrodes -- Design And Construction ; Electrodes -- Usage;
    ISSN: 00032700
    E-ISSN: 1520-6882
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  • 2
    Language: English
    In: Nature, March 19, 2015, Vol.519(7543), p.286(2)
    Keywords: Universities and Colleges – Human Resource Management ; Department Heads – Recruiting
    ISSN: 0028-0836
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  • 3
    In: Nature, 2015, Vol.519(7543), p.286
    Keywords: Leadership ; Personnel Selection -- Methods ; Professional Competence -- Standards ; Universities -- Organization & Administration;
    ISSN: 0028-0836
    E-ISSN: 1476-4687
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  • 4
    Language: English
    In: Social Science & Medicine, 2007, Vol.64(2), pp.287-291
    Description: This article builds on a previous study which found low numbers of patent applications for HIV antiretroviral drugs in African countries. A high level of variation was noted across individual countries, and consequently, the present study has sought to account for sources of the variation through statistical analyses. First, a correlation between the number of patents and HIV infection rate was observed ( =0.448, 〈0.001). T-tests identified significantly higher numbers of patents in national members of two intellectual property organizations (IPOs)—African Regional Intellectual Property Orginisation (ARIPO) and the Organisation Africaine de la Propriété Intellectualle (OAPI)—than in countries who did not belong to an intellectual property organization. The relationship between IPO membership and number of patents was also statistically significant in a multivariate Poisson regression. These findings demonstrate that higher numbers of patents are found in countries where they are more easily filed. This has important policy implications given the worldwide trend toward increased recognition of pharmaceutical patents.
    Keywords: Patents ; Access ; Antiretrovirals ; Africa ; HIV/AIDS ; Intellectual Property Organization (Ipo) ; Medicine ; Social Sciences (General) ; Public Health
    ISSN: 0277-9536
    E-ISSN: 1873-5347
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  • 5
    Language: English
    In: Proceedings of the National Academy of Sciences of the United States of America, 18 December 2012, Vol.109(51), pp.20907-12
    Description: Trimeric autotransporter adhesins (TAAs) are modular, highly repetitive surface proteins that mediate adhesion to host cells in a broad range of Gram-negative pathogens. Although their sizes may differ by more than one order of magnitude, they all follow the same basic head-stalk-anchor architecture, where the head mediates adhesion and autoagglutination, the stalk projects the head from the bacterial surface, and the anchor provides the export function and attaches the adhesin to the bacterial outer membrane after export is complete. In complex adhesins, head and stalk domains may alternate several times before the anchor is reached. Despite extensive sequence divergence, the structures of TAA domains are highly constrained, due to the tight interleaving of their constituent polypeptide chains. We have therefore taken a "domain dictionary" approach to characterize representatives for each domain type by X-ray crystallography and use these structures to reconstruct complete TAA fibers. With SadA from Salmonella enterica, EhaG from enteropathogenic Escherichia coli (EHEC), and UpaG from uropathogenic E. coli (UPEC), we present three representative structures of a complex adhesin that occur in a conserved genomic context in Enterobacteria and is essential in the infection process of uropathogenic E. coli. Our work proves the applicability of the dictionary approach to understanding the structure of a class of proteins that are otherwise poorly tractable by high-resolution methods and provides a basis for the rapid and detailed annotation of newly identified TAAs.
    Keywords: Adhesins, Bacterial -- Chemistry ; Enteropathogenic Escherichia Coli -- Metabolism ; Salmonella Enterica -- Metabolism
    ISSN: 00278424
    E-ISSN: 1091-6490
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  • 6
    Language: English
    In: Proceedings of the National Academy of Sciences of the United States, April 30, 2013, Vol.110(18), p.7440(6)
    Description: Extracellular signal-regulated kinases 1 and 2 (ERK1/2) are central mediators of cardiac hypertrophy and are discussed as potential therapeutic targets. However, direct inhibition of ERK1/2 leads to exacerbated cardiomyocyte death and impaired heart function. We have previously identified [ERK.sup.Thr188] autophosphorylation as a regulatory phosphorylation of ERK1/2 that is a key factor in cardiac hypertrophy. Here, we investigated whether interference with [ERK.sup.Thr188] phosphorylation permits the impairment of ERK1/2mediated cardiac hypertrophy without increasing cardiomyocyte death. The impact of [ERK.sup.Thr188] phosphorylation on cardiomyocyte hypertrophy and cell survival was analyzed in isolated cells and in mice using the mutant [ERK2.sup.T188A], which is dominant-negative for [ERK.sup.Thr188] signaling. [ERK2.sup.T188A] efficiently attenuated cardiomyocyte hypertrophic responses to phenylephrine and to chronic pressure overload, but it affected neither antiapoptotic ERK1/2 signaling nor overall physiological cardiac function. In contrast to its inhibition of pathological hypertrophy, [ERK2.sup.T188A] did not interfere with physiological cardiac growth occurring with age or upon voluntary exercise. A preferential role of [ERK.sup.Thr188] phosphorylation in pathological types of hypertrophy was also seen in patients with aortic valve stenosis: [ERK.sup.Thr188] phosphorylation was increased 8.5 [+ or -] 1.3-fold in high-gradient, rapidly progressing cases ([greater than or equal to] 40 mmHg gradient), whereas in low-gradient, slowly progressing cases, the increase was not significant. Because interference with [ERK.sup.Thr188] phosphorylation (i) inhibits pathological hypertrophy and (ii) does not impair antiapoptotic ERK1/2 signaling and because [ERK.sup.Thr188] phosphorylation shows strong prevalence for aortic stenosis patients with rapidly progressing course, we conclude that interference with [ERK.sup.Thr188] phosphorylation offers the possibility to selectively address pathological types of cardiac hypertrophy. MAPK | apoptosis | GPCRs www.pnas.org/cgi/doi/10.1073/pnas.1221999110
    Keywords: Heart Hypertrophy -- Research ; Heart Hypertrophy -- Physiological Aspects ; Heart -- Physiological Aspects ; Phosphotransferases -- Physiological Aspects
    ISSN: 0027-8424
    Source: Cengage Learning, Inc.
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  • 7
    Language: English
    In: The Journal of biological chemistry, 06 July 2012, Vol.287(28), pp.23407-17
    Description: Proteins controlling cellular networks have evolved distinct mechanisms to ensure specificity in protein-protein interactions. Raf kinase inhibitor protein (RKIP) is a multifaceted kinase modulator, but it is not well understood how this small protein (21 kDa) can coordinate its diverse signaling functions. Raf1 and G protein-coupled receptor kinase (GRK) 2 are direct interaction partners of RKIP and thus provide the possibility to untangle the mechanism of its target specificity. Here, we identify RKIP dimer formation as an important mechanistic feature in the target switch from Raf1 to GRK2. Co-immunoprecipitation and cross-linking experiments revealed RKIP dimerization upon phosphorylation of RKIP at serine 153 utilizing purified proteins as well as in cells overexpressing RKIP. A functional phosphomimetic RKIP mutant had a high propensity for dimerization and reproduced the switch from Raf1 to GRK2. RKIP dimerization and GRK2 binding, but not Raf1 interaction, were prevented by a peptide comprising amino acids 127-146 of RKIP, which suggests that this region is critical for dimer formation. Furthermore, a dimeric RKIP mutant displayed a higher affinity to GRK2, but a lower affinity to Raf1. Functional analyses of phosphomimetic as well as dimeric RKIP demonstrated that enhanced dimerization of RKIP translates into decreased Raf1 and increased GRK2 inhibition. The detection of RKIP dimers in a complex with GRK2 in murine hearts implies their physiological relevance. These findings represent a novel mechanistic feature how RKIP can discriminate between its different interaction partners and thus advances our understanding how specific inhibition of kinases can be achieved.
    Keywords: G-Protein-Coupled Receptor Kinase 2 -- Metabolism ; Mutant Proteins -- Metabolism ; Phosphatidylethanolamine Binding Protein -- Metabolism ; Proto-Oncogene Proteins C-Raf -- Metabolism
    E-ISSN: 1083-351X
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  • 8
    Language: English
    In: Deiss, Frédérique, Aaron Mazzeo, Estrella Hong, Donald E. Ingber, Ratmir Derda, and George M. Whitesides. 2013. “Platform for High-Throughput Testing of the Effect of Soluble Compounds on 3D Cell Cultures.” Analytical Chemistry 85(17): 8085–8094.
    Description: In vitro 3D culture could provide an important model of tissues in vivo, but assessing the effects of chemical compounds on cells in specific regions of 3D culture requires physical isolation of cells and thus currently relies mostly on delicate and low-throughput methods. This paper describes a technique (“cells-in-gels-in-paper”, CiGiP) that permits rapid assembly of arrays of 3D cell cultures and convenient isolation of cells from specific regions of these cultures. The 3D cultures were generated by stacking sheets of 200-μm-thick paper, each sheet supporting 96 individual “spots” (thin circular slabs) of hydrogels containing cells, separated by hydrophobic material (wax, PDMS) impermeable to aqueous solutions, and hydrophilic and most hydrophobic solutes. A custom-made 96-well holder isolated the cell-containing zones from each other. Each well contained media to which a different compound could be added. After culture and disassembly of the holder, peeling the layers apart “sectioned” the individual 3D cultures into 200-μm-thick sections which were easy to analyze using 2D imaging (e.g., with a commercial gel scanner). This 96-well holder brings new utilities to high-throughput, cell-based screening, by combining the simplicity of CiGiP with the convenience of a microtiter plate. This work demonstrated the potential of this type of assays by examining the cytotoxic effects of phenylarsine oxide (PAO) and cyclophosphamide (CPA) on human breast cancer cells positioned at different separations from culture media in 3D cultures.
    ISSN: 0003-2700
    Source: Harvard University Library
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  • 9
    Language: English
    In: Journal of animal science, October 2011, Vol.89(10), pp.3272-85
    Description: The present study evaluated whether feed deprivation can increase reactivity to stressful events, such as those that can occur at slaughter. Therefore, effects of 30 h of feed deprivation on behavior, including reactions to psychological stressors, and physiological status in cattle were determined. Sixteen Holstein cows (Exp. 1) and 32 Holstein heifers (Exp. 2) were either fed (FE) or 30-h feed deprived (FD). Throughout the first day of feed deprivation and during evening feed distribution to control animals, FD heifers and cows were more active than controls (P 〈 0.05). In Exp. 1, during a feeding test, in response to a sudden air blast arising from the bucket from which the cow was feeding, FD cows showed a longer latency to return to feed (P = 0.0002), spent less time in the bucket air blast zone (P = 0.008) and less time motionless (P = 0.03), and tended to withdraw over a longer distance (P = 0.07) than FE cows. In Exp. 2, during a reactivity test, FD heifers spent more (P = 0.0001) time motionless in response to social isolation than FE heifers. In Exp. 2, one-half of the FE and FD heifers were subjected to an additional physical and psychological stressor just before the reactivity test by driving them for 5 min through a labyrinth. Within heifers subjected to the additional stressor, FD heifers were less accepting of being detained (P = 0.05) and stroked (P = 0.003) by a familiar stockperson in a corner of the test arena. Compared with FE animals, FD heifers and FD cows had greater plasma cortisol concentrations (P 〈 0.05). Feed-deprived cows also had reduced β-hydroxybutyrate concentrations (P = 0.02) compared with FE cows. Thus, in cattle, FD influenced some of the classical indicators of energy metabolism and exacerbated reactivity to sudden events. In addition, when additional stressors were applied, FD cattle were more reluctant to accept handling. Results indicate that a multifactorial origin of stressors during the slaughter period may synergistically increase psychological stress of cattle.
    Keywords: Behavior, Animal -- Physiology ; Cattle -- Physiology ; Food Deprivation -- Physiology
    ISSN: 00218812
    E-ISSN: 1525-3163
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  • 10
    Language: English
    In: Journal of animal science, November 2013, Vol.91(11), pp.5418-26
    Description: Between-farm variation in animal reactions to humans can reflect different management styles and behavioral tendencies among farmers. Animals are well known to discriminate among humans, but less clear is the key issue of whether they more or less easily generalize their experience from specific humans to others depending on management style. Here, we chose 2 contrasted management styles by known handlers: "gentle" management, that is, long-lasting exposure to positive human interactions (with limited negative interactions), and "aversive" management including long-lasting exposure to various negative human interactions (with only food delivery considered a positive interaction) and aversive events. Over a period of 19 wk, 15 female lambs were exposed to the gentle management treatment ("gently treated" group) and another 15 lambs ("aversively treated" group) were exposed to the aversive management treatment. To facilitate discrimination by animals, experimenters wore white clothes for aversive events and green clothes for farming handling (positive handling and feeding for the gently treated group and only feeding for the aversively treated group). Sheep perception of the human was assessed after the management period by submitting lambs from each group to 2 standardized tests: 1) the presence of a stationary human (familiar human in white vs. familiar human in green vs. unknown human) and 2) the presence of a moving human (familiar human in white vs. familiar human in green vs. unknown human). As expected, during the stationary human test, aversively treated lambs spent less time in the human zone (P〈0.0001), showed greater latency to approach the human (P=0.05), and had fewer contacts with the human (P=0.05) than gently treated lambs. During the moving human test, aversively treated lambs also showed a greater escape distance from humans than gently treated lambs (P〈0.0001). Aversively treated lambs showed the same fear responses towards familiar and unknown humans and tended to generalize their aversive experiences with one handler to all humans. In contrast, gently treated lambs seemed to discriminate familiar humans from unfamiliar humans. Different management styles could modulate farm generalization to humans in farm animals.
    Keywords: Animal Welfare ; Handling (Psychology) ; Animal Husbandry -- Methods ; Sheep -- Physiology ; Stress, Psychological -- Psychology
    ISSN: 00218812
    E-ISSN: 1525-3163
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