32 research outputs found

    Book Reviews

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    DELINQUENTS, THEIR FAMILIES AND THE COMMUNITY. By C. Downing Tait, Jr. M.D. and Emory F. Hodges, Jr., M.D. JURISPRUDENCE: THE PHILOSOPHY AND METHOD OF THE LAW. By Edgar Bodenheimer

    The Pennsylvania Comparative Negligence Act - An Alien Intruder in the House of Common Law

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    Using the Pennyslvania [sic] legislature\u27s recent enactment of a comparative negligence statute as a vehicle, the author asserts that the courts can and should reevaluate common law concepts as they apply to cases which, although pending at the time of a legislative change in the common law, are not subject to the basically prospective statutory provisions

    Peptide hairpins with strand segments containing α- and β-amino acid residues: Cross-strand aromatic interactions of facing Phe residues

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    The incporation of β-amino acid residues into the strand segments of designed β-hairpin leads to the formation of polar sheets, since in the case of β-peptide strands, all adjacent carbonyl groups point in one direction and the amide groups orient in the opposite direction. The conformational analysis of two designed peptide hairpins composed of α/β-hybrid segments are described: Boc-βLeu-βPhe-Val-D-Pro-Gly-βLeu-βPhe-Val-OMe (1) and Boc-βLeu-Phe-βVal-D-Pro-Gly-βLeu-Phe-βVal-OMe (2). A 500-MHz 1H-NMR (nuclear magnetic resonance) analysis in methanol supports a significant population of hairpin conformations in both peptides. Diagnostic nuclear Overhauser effects (NOEs) are observed in both cases. X-ray diffraction studies on single crystals of peptide 1 reveal a β-hairpin conformation in both the molecules, which constitute the crystallographic asymmetric unit. Three cross-strand hydrogen bonds and a nucleating type II′ β-turn at the D-Pro-Gly segment are observed in the two independent molecules. In peptide 1, the Phe residues at positions 2 and 7 occur at the nonhydrogen-bonding position, with the benzyl side chains pointing on opposite faces of the β-sheet. The observed aromatic centroid-to-centroid distances are 8.92 Å (molecule A) and 8.94 Å (molecule B). In peptide 2, the aromatic rings must occupy facing positions in antiparallel strands, in the NMR-derived structure. Peptide 1 yields a normal hairpin-like CD spectrum in methanol with a minimum at 224 nm. The CD spectrum of peptide 2 reveals a negative band at 234 nm and a positive band at 221 nm, suggestive of an exciton split doublet. Modeling of the facing Phe side chains at the hydrogen-bonding position of a canonical β-hairpin suggests that interring separation is 4.78 Å for the gauche+gauche- (g+g-) rotamer. A previously reported peptide β-hairpin composed of only α-amino acids, Boc-Leu-Phe-Val-D-Pro-Gly-Leu-Phe-Val-OMe also exhibited an anomalous far-UV (ultraviolet) CD (circular dichroism) spectrum, which was interpreted in terms of interactions between facing aromatic chromophores, Phe 2 and Phe

    Two novel hexadepsipeptides with several modified amino acid residues isolated from the fungus isaria

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    Two new cyclohexadepsipeptides have been isolated from the fungus Isaria. Fungal growth in solid media yielded hyphal strands from which peptide fractions were readily isolable by organic-solvent extraction. Two novel cyclodepsipeptides, isaridin A and isaridin B, have been isolated by reverse-phase HPLC, and characterized by ESI-MS and 1H-NMR. Single crystals of both peptides have been obtained, and their 3D structures were elucidated by X-ray diffraction. The isaridins contain several unusual amino acid residues. The sequences are cyclo(β-Gly-HyLeu-Pro-Phe-NMeVal-NMePhe) and cyclo(β-Gly-HyLeu-β-MePro-Phe-NMeVal-NMePhe), where NMeVal is N-methylvaline, NMePhe N-methylphenylalanine, and HyLeu hydroxyleucine (=2-hydroxy-4-methylpentanoic acid). The two peptides differ from one another at residue 3, isaridin A having an (S)-proline at this position, while β-methyl-(S)-proline (=(2S,3S)-2,3,4,5-tetrahydro-3-methyl-1H-pyrrole-2-carboxylic acid) is found in isaridin B. The solid-state conformations of both cyclic depsipeptides are characterized by the presence of two cis peptide bonds at HyLeu(2)-Pro(3)/HyLeu(2)-β-MePro(3) and NMeVal(5)-NMePhe(6), respectively. In isaridin A, a strong intramolecular H-bond is observed between Phe(4)CO...HNβ-Gly(1), and a similar, but weaker, interaction is observed between β-Gly(1)COHNPhe(4). In contrast, in isaridin B, only a single intramolecular H-bond is observed between β-Gly(1)CO...HNPhe(4)

    International Coercion, Emulation and Policy Diffusion: Market-Oriented Infrastructure Reforms, 1977-1999

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    Why do some countries adopt market-oriented reforms such as deregulation, privatization and liberalization of competition in their infrastructure industries while others do not? Why did the pace of adoption accelerate in the 1990s? Building on neo-institutional theory in sociology, we argue that the domestic adoption of market-oriented reforms is strongly influenced by international pressures of coercion and emulation. We find robust support for these arguments with an event-history analysis of the determinants of reform in the telecommunications and electricity sectors of as many as 205 countries and territories between 1977 and 1999. Our results also suggest that the coercive effect of multilateral lending from the IMF, the World Bank or Regional Development Banks is increasing over time, a finding that is consistent with anecdotal evidence that multilateral organizations have broadened the scope of the “conditionality” terms specifying market-oriented reforms imposed on borrowing countries. We discuss the possibility that, by pressuring countries into policy reform, cross-national coercion and emulation may not produce ideal outcomes.http://deepblue.lib.umich.edu/bitstream/2027.42/40099/3/wp713.pd

    Abstracts of presentations on plant protection issues at the xth international congress of virology: August 11-16,1996 Binyanei haOoma, Jerusalem, Israel Part 2 Plenary Lectures

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    Socializing One Health: an innovative strategy to investigate social and behavioral risks of emerging viral threats

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    In an effort to strengthen global capacity to prevent, detect, and control infectious diseases in animals and people, the United States Agency for International Development’s (USAID) Emerging Pandemic Threats (EPT) PREDICT project funded development of regional, national, and local One Health capacities for early disease detection, rapid response, disease control, and risk reduction. From the outset, the EPT approach was inclusive of social science research methods designed to understand the contexts and behaviors of communities living and working at human-animal-environment interfaces considered high-risk for virus emergence. Using qualitative and quantitative approaches, PREDICT behavioral research aimed to identify and assess a range of socio-cultural behaviors that could be influential in zoonotic disease emergence, amplification, and transmission. This broad approach to behavioral risk characterization enabled us to identify and characterize human activities that could be linked to the transmission dynamics of new and emerging viruses. This paper provides a discussion of implementation of a social science approach within a zoonotic surveillance framework. We conducted in-depth ethnographic interviews and focus groups to better understand the individual- and community-level knowledge, attitudes, and practices that potentially put participants at risk for zoonotic disease transmission from the animals they live and work with, across 6 interface domains. When we asked highly-exposed individuals (ie. bushmeat hunters, wildlife or guano farmers) about the risk they perceived in their occupational activities, most did not perceive it to be risky, whether because it was normalized by years (or generations) of doing such an activity, or due to lack of information about potential risks. Integrating the social sciences allows investigations of the specific human activities that are hypothesized to drive disease emergence, amplification, and transmission, in order to better substantiate behavioral disease drivers, along with the social dimensions of infection and transmission dynamics. Understanding these dynamics is critical to achieving health security--the protection from threats to health-- which requires investments in both collective and individual health security. Involving behavioral sciences into zoonotic disease surveillance allowed us to push toward fuller community integration and engagement and toward dialogue and implementation of recommendations for disease prevention and improved health security

    Differing patterns in the self-assembly of radially anchored imidazoles, 1,3,5-Tris(1 H -imidazol-2-yl)benzene and 1,3-Bis(1 H -imidazol-2-yl)benzene

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    The novel 3-fold symmetric 1,3,5-tris(1H-imidazol-2-yl)benzene, having a propensity for a 3-fold salt formation by hydrogen bonding at the periphery, was prepared from oxidation of the hexahydro imidazole precursor. The transformation proved difficult and, of the many reagents tried, only barium manganate and o-iodoxy benzoic acid were successful. The oxidation to the aromatic 1,3,5-tris imidazolyl benzene produces dramatic changes, particularly when the X-ray structures of their tris-TFA (trifluoroacetic acid) salts are compared. While the hexahydro precursor exhibited a herringbone type arrangement in the crystal, the oxidation resulted in almost co-planar molecules that formed parallel stacks separated by 3.57 Ă… between the atoms in separate planes. 1,3-Bis(1H-imidazole-2-yl)benzene is an attractive core unit for assembly using a variety of auxiliaries. Several attempts to complex the bis-imidazole with organic acids failed. These efforts lead to the serendipitous discovery of a novel tetrameric assembly, mediated by water molecules, which was confirmed by crystallization of the bis imidazole from water

    Unique assemblies of alternating positively and negatively charged layers, directed by hydrogen bonds, ionic interactions, and Π-stacking in the crystal structures of complexes between mellitic acid (benzenehexacarboxylic acid) and five planar aromatic bases

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    Benzenehexacarboxylic acid, mellitic acid (MA), has been used as a core motif to study possible radial self-assembly using complementary aromatic bases. By mixing water solutions of the components, crystals of the salts of MA with 4-aminopyridine (AP), 4-dimethylamino-pyridine (DM), 2,2P̅1 , a =8.257(2)Å, b =8.986(2)Å, c =9.383(1)Å, α=98.60(1)°, β=96.38(2)°, γ=117.07(1)°
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