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Hinges
Kinds of Hinges Terms modified by Hinges Selected AbstractsA note on hinge-free topology design using the special triangulation of design elementsINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING, Issue 12 2005Jae Eun Kim Abstract Hinges, the unrepeated checkerboard cells, may appear in the topology optimization using low-order finite elements, especially for compliant mechanism design. Existing hinge-controlling methods are based on the rectangular element discretization, so slant or curved boundary lines may not be represented satisfactorily. To avoid hinge formation and to represent curved boundary lines better, we consider a macro-design element method which subdivides the design element into eight triangular finite elements; the finite element calculation is carried out with triangular elements, but the design variables are defined at the nodes defining rectangular macro-design elements. For hinge-free results, different stiffness interpolations are suggested depending on whether the triangular element belongs to a master group or a slave group. The performance of the proposed method was checked with compliant mechanism design problems from the viewpoint of hinge suppression and the possibility of generating slant boundary lines. Copyright © 2005 John Wiley & Sons, Ltd. [source] A Two Degree of Freedom Gripper Actuated by SMA with Flexure HingesJOURNAL OF FIELD ROBOTICS (FORMERLY JOURNAL OF ROBOTIC SYSTEMS), Issue 11 2003A. Manuello Bertetto A gripper prototype was designed and built. It is made by a rigid structure articulated by compliant hinges. Its kinematics consists of both parallel and angular finger motion. The movements were designed to be independent from each other and auto-adaptive as well. The motions were driven by Ni-Ti shape memory alloy (SMA) wires. The recovery position is achieved by the elastic force exerted by the flexure hinges in the case of parallel motion and by an axial spring in the case of angular motion. Both the actuators and the hinges were experimentally characterized by suitable test rigs. The gripper prototype was tested and it showed to be able to reach the design performances. © 2003 Wiley Periodicals, Inc. [source] Development and validation of a metallic haunch seismic retrofit solution for existing under-designed RC frame buildingsEARTHQUAKE ENGINEERING AND STRUCTURAL DYNAMICS, Issue 14 2006Stefano Pampanin Abstract The feasibility and efficiency of a seismic retrofit solution for existing reinforced concrete frame systems, designed before the introduction of modern seismic-oriented design codes in the mid 1970s, is conceptually presented and experimentally investigated. A diagonal metallic haunch system is introduced at the beam,column connections to protect the joint panel zone from extensive damage and brittle shear mechanisms, while inverting the hierarchy of strength within the beam,column subassemblies and forming a plastic hinge in the beam. A complete step-by-step design procedure is suggested for the proposed retrofit strategy to achieve the desired reversal of strength hierarchy. Analytical formulations of the internal force flow at the beam,column-joint level are derived for the retrofitted joints. The study is particularly focused on exterior beam,column joints, since it is recognized that they are the most vulnerable, due to their lack of a reliable joint shear transfer mechanism. Results from an experimental program carried out to validate the concept and the design procedure are also presented. The program consisted of quasi-static cyclic tests on four exterior, , scaled, beam,column joint subassemblies, typical of pre-1970 construction practice using plain round bars with end-hooks, with limited joint transverse reinforcement and detailed without capacity design considerations. The first (control specimen) emulated the as-built connection while the three others incorporated the proposed retrofitted configurations. The experimental results demonstrated the effectiveness of the proposed solution for upgrading non-seismically designed RC frames and also confirmed the applicability of the proposed design procedure and of the analytical derivations. Copyright © 2006 John Wiley & Sons, Ltd. [source] SMAP-29 has two LPS-binding sites and a central hingeFEBS JOURNAL, Issue 4 2002Brian F. Tack The CD spectra of SMAP-29, an antimicrobial peptide from sheep, showed disordered structure in aqueous buffers, and significant helicity in membrane-like environments, including SDS micelles, lipopolysaccharide (LPS) dispersions, and trifluoroethanol buffer systems. A structure determined by NMR in 40% perdeuterated trifluoroethanol indicated that residues 8,17 were helical, residues 18,19 formed a hinge, and residues 20,28 formed an ordered, hydrophobic segment. SMAP-29 was flexible in 40% trifluoroethanol, forming two sets of conformers that differed in the relative orientation of the N-terminal domain. We used a chromogenic Limulus assay to determine the EC50 of the peptide (the concentration that bound 50% of the added LPS). Studies with full-length and truncated SMAP-29 molecules revealed that each end of the holopeptide contained an LPS-binding domain. The higher affinity LPS-binding domain was situated in the flexible N-terminal portion. LPS binding to full-length SMAP-29 showed positive cooperativity, so the EC50 of the peptide (2.6 µm) was considerably lower than that of the individual LPS-binding domains. LPS-binding studies with a mixture of truncated peptides revealed that this cooperativity was primarily intramolecular (i.e. involving the N- and C-terminal LPS-binding sites of the same peptide molecule). CAP-18[106,142], an antimicrobial cathelicidin peptide of rabbits, resembled SMAP-29 in that it contained N- and C-terminal LPS-binding domains, had an EC50 of 2.5 µm, and bound LPS with positive cooperativity. We conclude that the presence of multiple binding sites that function cooperatively allow peptides such as SMAP-29 and CAP-18 to bind LPS with high affinity. [source] Assembly of the Rieske iron,sulphur protein into the cytochrome bf complex in thylakoid membranes of isolated pea chloroplastsFEBS JOURNAL, Issue 2 2000Aliki Kapazoglou The assembly of the Rieske iron,sulphur protein into the cytochrome bf complex was examined following import of 35S-labeled precursor protein by isolated pea chloroplasts. Rieske protein assembled into the cytochrome bf complex was resolved from unassembled Rieske protein and from other membrane complexes by nondenaturing gel electrophoresis of dodecyl maltoside-solubilized thylakoid membranes. Four mutant forms of the Rieske protein were able to assemble into the cytochrome bf complex in isolated chloroplasts. These were a triple substitution mutant, C107S/H109R/C112S, replacing conserved residues involved in the ligation of the [2Fe-2S] centre; the mutant ,45,52 which removed a glycine-rich region predicted to form a flexible hinge between the hydrophobic membrane-associated region and the hydrophilic lumenal domain; and mutants ,168,173 and ,177,179 which removed two C-terminal regions, which are highly conserved in chloroplast and cyanobacterial Rieske proteins. This indicates that the [2Fe,2S] cluster, the glycine-rich region and the C-terminal region are not essential for stable assembly of the Rieske protein into the cytochrome bf complex in isolated chloroplasts. [source] Mammalian Mcm2/4/6/7 complex forms a toroidal structureGENES TO CELLS, Issue 5 2003Norikazu Yabuta Background: The Mcm proteins are a family of six homologous proteins (Mcm2,7) that play an important role in DNA replication. They form Mcm4/6/7 and Mcm2/4/6/7 complexes, but their structures are not known. Results: We found that the human Mcm2/4/6/7 tetramer forms a toroidal structure, with a central cavity about 3,4 nm in diameter. Observations were made using electron microscopy, employing the image analysis of single particles. The most predominant averaged image displayed a toroid harbouring four bulges forming corners, one of which was larger than the others. This structure was very similar to the mouse Mcm2/4/6/7 tetramer that was independently prepared and analysed by electron microscopy. These toroidal structures are distinct from that of the Mcm4/6/7 hexamer, which was also examined by electron microscopy. GST(glutathione S-transferase)-pull down and two hybrid experiments suggest that a putative Mcm6-Mcm6 hinge contributes to the formation of the Mcm7/4/6/6/4/7 heterohexamer. Conclusions: The Mcm2/4/6/7 tetramer forms a toroidal structure that is distinct from that of the Mcm4/6/7 hexamer in size and shape. [source] The hinge region fragment of immunoglobulin G improves immunogenicity of recombinant gonadotrophin-releasing hormone conjugated to the T-helper epitope in designing peptide vaccinesIMMUNOLOGY, Issue 1pt2 2009Jinshu Xu Summary In our previous study, the hinge fragment (225,232/225,,232,) of human immunoglobulin G1 (IgG1) was used as a space peptide linker for synthesizing the GnRH3,hinge,MVP chimeric peptide, whereby three repeated gonadotrophin-releasing hormone (GnRH) units and a T-cell epitope from measles virus fusion protein (MVP) were amide-bond-linked at the N and C terminus, respectively, to the hinge peptide for producing anti-GnRH antibody responses. To investigate whether or not the hinge region fragment can improve the immunogenicity of GnRH, we further synthesized and purified GnRH3,hinge,MVP, GnRH3,hinge and GnRH3,MVP using recombinant DNA technology. Under high pH conditions, GnRH3,hinge,MVP was capable of forming double-chain structures. Immunization of male mice with the immunogens of GnRH3,hinge,MVP resulted in the generation of high-titre antibodies specific for GnRH. The synthetic GnRH3,hinge and GnRH3,MVP induced a lower titre of anti-GnRH antibody than GnRH3,hinge,MVP. This was followed by a decrease in serum testosterone levels, which resulted in a low level of expression of the relaxin-like factor gene in the testis. Our data suggest that peptide and T-cell epitopes oriented at the N-terminus or C-terminus of hinge peptides simplify the antigenic peptide conjugates and may be considered as potential synthetic immunogens. [source] The transfer matrix method applied to steel sheet pile wallsINTERNATIONAL JOURNAL FOR NUMERICAL AND ANALYTICAL METHODS IN GEOMECHANICS, Issue 6 2003D. A. Kort Abstract This paper proposes two subgrade reaction models for the analysis of steel sheet pile walls based on the transfer matrix method. In the first model a plastic hinge is generated when the maximum moment in the retaining structure is exceeded. The second model deals with a beam with an asymmetrical cross-section that can bend in two directions. In the first part of this paper the transfer matrix method is explained on the basis of a simple example. Further the development of two computer models is described: Plaswall and Skewwall. The second part of this paper deals with an application of both models. In the application of Plaswall the effect of four current earth pressure theories to the subgrade reaction method is compared to a finite element calculation. It is shown that the earth pressure theory is of major importance on the calculation result of a sheet pile wall both with and without a plastic hinge. In the application of Skewwall the effectiveness of structural measures to reduce oblique bending is investigated. The results are compared to a 3D finite element calculation. It is shown that with simple structural measures the loss of structural resistance due to oblique bending can be reduced. Copyright © 2003 John Wiley & Sons, Ltd. [source] Topographic Anatomy of the Inferior Pyramidal Space: Relevance to Radiofrequency Catheter AblationJOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 2 2001DAMIÁN SÁNCHEZ-QUINTANA M.D. Inferior Pyramidal Space and Ablation.Introduction: Radiofrequency catheter ablation carried out in the vicinity of the triangle of Koch risks damaging not only the AV conduction tissues but also their arterial supply. The aim of this study was to examine the relationship of the AV nodal artery to the inferior pyramidal space, the triangle of Koch, and the right atrial endocardial surface. Methods and Results: We studied 41 heart specimens, 24 by gross dissections and 17 by histologic sections. The proximity of the AV nodal artery to the surface landmarks of the triangle of Koch was variable, but it was notable that in 75% of specimens the artery passed close to the endocardial surface of the right atrium and within 0.5 to 5 mm of the mouth of the coronary sinus. In all specimens, the mean distance of the artery to the endocardial surface was 3.5 ± 1.5 mm at the base of Koch's triangle. The location of the compact AV node and its inferior extensions varied within the landmarks of the triangle. At the mid-level of Koch's triangle, the compact node was medially situated in 82% of specimens, but it was closer to the hinge of the tricuspid valve in the remaining 18% of specimens. In 12% of specimens, the inferior parts of the node extended to the level of the mouth of the coronary sinus. Conclusion: The nodal artery runs close to the orifice of the coronary sinus, the endocardial surface of the right atrium, the middle cardiac vein, and the specialized conduction tissues in most hearts. The nodal artery and/or the AV conduction tissues can be at risk of damage when ablative procedures are carried out at the base of the triangle of Koch. [source] An ex ante economic and policy analysis of research on genetic resistance to livestock disease: trypanosomosis in AfricaAGRICULTURAL ECONOMICS, Issue 2-3 2001Cesar A. Falconi Abstract This paper undertakes an ex ante economic analysis of research on how resistance to trypanosomosis-a dominant livestock disease in Africa-can be maintained and enhanced while retaining and reinforcing characteristics of economic importance to farmers, and on how,trypanotolerance' can be imparted to susceptible animals while retaining their other important traits. The results indicate that potential benefits to research-historically field-based but increasingly biotechnology-driven-range from two to nine times potential costs and that the internal rate of return on investments can be six times the real interest rate. Field-based research, while exhibiting lower potential benefits on aggregate than does biotechnology research, is also less costly and, because of its more immediate payback, has higher internal rates of return. Returns to biotechnology research hinge on close links with field-based research and on strategic but relatively small incremental human and capital investments. The results also suggest that further research is needed to consistently identify and track the impacts of alternative intellectual property rights (IPRs) options on the levels and distributions of biotechnology research benefits. [source] The Present and Future of MFT Doctoral Education in Research-Focused UniversitiesJOURNAL OF MARITAL AND FAMILY THERAPY, Issue 3 2010Douglas H. Sprenkle Doctoral education is greatly impacted by context, and the large majority of marital and family therapy (MFT) doctoral programs are PhD programs in research-focused universities. I believe their primary mission is to equip students to become scientist,practitioners and do original research that will advance the science of the discipline, whereas the mission of the typical master's program is to produce strong practitioners who are research informed. It is the emphasis on the scientific method, not the content specialty area, that should be the hallmark of PhD programs in research-focused contexts. I describe metrics for success that include not only research productivity but also the development of a supportive, open, flexible, and generous program culture. The research mission of these programs has been only modestly helped by the Commission on Accreditation for Marriage and Family Therapy Education process and the programs are largely not doing the programmatic intervention research that the field needs. As the universities that house these programs are also "raising the bar," the long-term viability of the programs themselves will likely hinge on success in this arena. [source] Microstructural, chemical and textural records during growth of snowball garnetJOURNAL OF METAMORPHIC GEOLOGY, Issue 6 2009M. ROBYR Abstract The growth history of two populations of snowball garnet from the Lukmanier Pass area (central Swiss Alps) was examined through a detailed analysis of three-dimensional geometry, chemical zoning and crystallographic orientation. The first population, collected in the hinge of a chevron-type fold, shows an apparent rotation of 360°. The first 270° are characterized by spiral-shaped inclusion trails, gradual and concentric Mn zoning and a single crystallographic orientation, whereas in the last 90°, crenulated inclusion trails and secondary Mn maxima centred on distinct crystallographic garnet domains are observed. Microstructural, geochemical and textural data indicate a radical change in growth regime between the two growth sequences. In the first 270°, growth occurred under rotational non-coaxial flow, whereas in the last 90°, garnet grew under a non-rotational shortening regime. The second population, collected in the limb of the same chevron-type fold structure, is characterized by a spiral geometry that does not exceed 270° of apparent rotation. These garnet microstructures do not record any evidence for a modification of the stress field during garnet growth. Concentric Mn zoning as well as a single crystallographic orientation are observed for the entire spiral. Electron backscatter diffraction data indicate that nearly all central domains in the snowball garnet are characterized by one [001] axis oriented (sub-)parallel to the symmetry axis and by another [001] axis oriented (sub-)parallel to the orientation of the internal foliation. These features suggest that the crystallographic orientation across the garnet spiral is not random and that a relation exists among the symmetry axis, the internal foliation and the crystallographic orientation. [source] Inconsistencies Between Actual and Estimated Blood Alcohol Concentrations in a Field Study of College Students: Do Students Really Know How Much They Drink?ALCOHOLISM, Issue 9 2005Courtney L. Kraus Background: Alcohol use by college students is commonly measured through the use of surveys. The validity of such data hinge on the assumption that students are aware of how much alcohol they actually consume. Recent studies call this assumption into question. Students tend to overestimate the appropriate sizes of standard drinks, suggesting that they might underestimate how much alcohol they consume. If this is true, then students' actual blood alcohol concentrations (BACs) should be higher than BACs estimated based on self-report data. The present study examined this issue Methods: Breathalyzer readings and self-reported drinking data were collected from 152 college students during the fall of 2004. Estimated BACs were calculated by means of a standard formula, and the relation between actual and estimated BACs was examined. Factors contributing to discrepancies between the two values were identified Results: Estimated BAC levels were significantly higher, not lower, than breath BAC measures. The accuracy of estimated BACs decreased as the number of drinks and amount of time spent drinking increased. Being male and drinking only beer predicted greater accuracy of estimated BACs Conclusions: Although laboratory data suggest that students underestimate how much they drink, the hypothesis was not supported by data collected in the field. It appears that students might actually overestimate rather than underestimate their levels of consumption when surveyed in the midst of a night of drinking. The findings corroborate observations made by other researchers and suggest that the findings of laboratory studies on college drinking do not necessarily extend to real-world settings. [source] Simple small-size coupled-fed uniplanar PIFA for multiband clamshell mobile phone applicationMICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 12 2009Ting-Wei Kang Abstract In this study, a simple uniplanar printed PIFA occupying a small area of 10 × 40 mm2 for achieving multiband operation in the clamshell mobile phone is presented. The proposed PIFA is formed by a simple shorted radiating strip coupled-fed by a simple feeding strip and is mounted at the hinge of the clamshell mobile phone; further, the upper ground plane is connected to the main ground plane using an extended connecting strip. With the coupling feed and the connection arrangement between the main and upper ground planes, the proposed PIFA itself is not only an efficient radiator, it can also excite the two ground planes of the clamshell mobile phone as an efficient radiator (dipole-like resonant modes are excited). Thus, with a small occupying area and a simple structure for the proposed PIFA, two wide operating bands at lower and higher frequencies can be provided to cover GSM850/900/1800/1900/UMTS bands for WWAN operation. The antenna also meets the 1-g SAR specification of 1.6 W/kg required for practical applications. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 2805,2810, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24756 [source] Optical fiber-based macrobend free air flow sensor using a hinge joint: A preliminary reportMICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 10 2008Anu Vijayan Abstract A novel idea of hinge joint is explored to cause macrobend in optical fiber and is explored for its use as a flow sensor. The bending of the fiber at the hinge changes the intensity of light traveling through the optical fiber. This can ideally be used in areas where air flow upto 10 lit/min needs to be monitored continuously. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 2543,2546, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23746 [source] Determinants of bacteriophage P22 polyhead formation: the role of coat protein flexibility in conformational switchingMOLECULAR MICROBIOLOGY, Issue 6 2010Margaret M. Suhanovsky Summary We have investigated determinants of polyhead formation in bacteriophage P22 in order to understand the molecular mechanism by which coat protein assembly goes astray. Polyhead assembly is caused by amino acid substitutions in coat protein at position 170, which is located in the ,-hinge. In vivo scaffolding protein does not correct polyhead assembly by F170A or F170K coat proteins, but does for F170L. All F170 variants bind scaffolding protein more weakly than wild-type as observed by affinity chromatography with scaffolding protein-agarose and scaffolding protein shell re-entry experiments. Electron cryo-microscopy and three-dimensional image reconstructions of F170A and F170K empty procapsid shells showed that there is a decreased flexibility of the coat subunits relative to wild-type. This was confirmed by limited proteolysis and protein sequencing, which showed increased protection of the A-domain. Our data support the conclusion that the decrease in flexibility of the A-domain leads to crowding of the subunits at the centre of the pentons, thereby favouring the hexon configuration during assembly. Thus, correct coat protein interactions with scaffolding protein and maintenance of sufficient coat protein flexibility are crucial for proper P22 assembly. The coat protein ,-hinge region is the major determinant for both features. [source] The Political Economy of the Ecological NativeAMERICAN ANTHROPOLOGIST, Issue 3 2007MOLLY DOANE In Chimalapas, Mexico, nongovernmental actors attempted to integrate campesinos into the discourse and practices of the Western environmental movement. The political economy school of anthropology assumes that cultural identity and practice flow from historical experiences grounded in relevant national and institutional contexts. In this article, I argue that although the movement in Chimalapas drew from the well-developed symbolic toolkit of the environmental movement, it was not able to create a space for local concerns within a transnational agenda that was already fairly well established and inflexible. Political ecology was the hinge of this movement: a political-economic analysis that validated traditional agrarian concerns in Chimalapas but included an environmentalist discourse legible to international funders. In this way, environmentalists in Chimalapas attempted both to create new practices and to link old practices to new expressions of culture and identity. [source] A Note on Scripture in the,Summa theologiaeNEW BLACKFRIARS, Issue 1030 2009Matthew Levering Abstract Beginning with the question of whether Aquinas's,Summa theologiae,inevitably distorts the meaning of biblical texts by removing them from their narrative context, this essay suggests that one way to think about Aquinas's use of Scripture in the,Summa theologiae,is to read together, as an ensemble, the biblical texts that he cites when treating a particular theme. Focusing on his first four questions on the virtue of faith (ST,II-II, qq. 1,4), I argue that Aquinas's selection of biblical texts from across the canonical Scriptures enables him to provide a nuanced biblical perspective on a particular theme even without finding it necessary to quote Scripture in every article. I seek to bring to light the way that the various biblical texts in the question,whose functions within the articles are widely diverse, from providing the hinge for a,responsio,to framing a minor objection,complement and echo one another. [source] The role of strand 1 of the C ,-sheet in the structure and function of ,1 -antitrypsinPROTEIN SCIENCE, Issue 12 2001Stephen P. Bottomley Abstract Serpins inhibit cognate serine proteases involved in a number of important processes including blood coagulation and inflammation. Consequently, loss of serpin function or stability results in a number of disease states. Many of the naturally occurring mutations leading to disease are located within strand 1 of the C ,-sheet of the serpin. To ascertain the structural and functional importance of each residue in this strand, which constitutes the so-called distal hinge of the reactive center loop of the serpin, an alanine scanning study was carried out on recombinant ,1 -antitrypsin Pittsburgh mutant (P1 = Arg). Mutation of the P10, position had no effect on its inhibitory properties towards thrombin. Mutations to residues P7, and P9, caused these serpins to have an increased tendency to act as substrates rather than inhibitors, while mutations at P6, and P8, positions caused the serpin to behave almost entirely as a substrate. Mutations at the P6, and P8, residues of the C ,-sheet, which are buried in the hydrophobic core in the native structure, caused the serpin to become highly unstable and polymerize much more readily. Thus, P6, and P8, mutants of ,1 -antitrypsin had melting temperatures 14 degrees lower than wild-type ,1 -antitrypsin. These results indicate the importance of maintaining the anchoring of the distal hinge to both the inhibitory mechanism and stability of serpins, the inhibitory mechanism being particularly sensitive to any perturbations in this region. The results of this study allow more informed analysis of the effects of mutations found at these positions in disease-associated serpin variants. [source] Shifting adaptive landscapes: Progress and challenges in reconstructing early hominid environmentsAMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY, Issue S45 2007John D. Kingston Abstract Since Darwin situated humans in an evolutionary framework, much discussion has focused on environmental factors that may have shaped or influenced the course of human evolution. Developing adaptive or causal perspectives on the morphological and behavioral variability documented in the human fossil record requires establishing a comprehensive paleoenvironmental context. Reconstructing environments in the past, however, is a complex undertaking, requiring assimilation of diverse datasets of varying quality, scale, and relevance. In response to these difficulties, human evolution has traditionally been interpreted in a somewhat generalized framework, characterized primarily by increasing aridity and seasonality periodically punctuated by pulses or intervals of environmental change, inferred largely from global climatic records. Although these broad paradigms provide useful heuristic approaches for interpreting human evolution, the spatiotemporal resolution remains far too coarse to develop unambiguous causal links. This challenge has become more acute as the emerging paleoenvironmental evidence from equatorial Africa is revealing a complex pattern of habitat heterogeneity and persistent ecological flux throughout the interval of human evolution. In addition, recent discoveries have revealed significant taxonomic diversity and substantially increased the geographic and temporal range of early hominids. These findings raise further questions regarding the role of the environment in mediating or directing the course of human evolution. As a consequence, it is imperative to critically assess the environmental criteria on which many theories and hypotheses of human evolution hinge. The goals here are to 1) compile, review, and evaluate relevant paleoecological datasets from equatorial Africa spanning the last 10 Ma, 2) develop a hierarchical perspective for developing and evaluating hypotheses linking paleoecology to patterns and processes in early hominid evolution, and 3) suggest a conceptual framework for modeling and interpreting environmental data relevant to human evolution in equatorial Africa. Yrbk Phys Anthropol 50:20,58, 2007. © 2007 Wiley-Liss, Inc. [source] The Ashele VMS-type Cu-Zn Deposit in Xinjiang, NW China Formed in a Rifted Arc SettingRESOURCE GEOLOGY, Issue 2 2010Bo Wan Abstract The Ashele Cu-Zn deposit is a typical VMS deposit in Chinese Altay located in the southern margin of the Altaid orogen. The deposit occurred in the polyphase fold system, and the main orebody is located at the hinge of the syncline. All orebodies show lenticular form, and are stratabound by a suite of early to middle Devonian bimodal volcanic rocks. The hosting basalt is low K tholeiite and characterized with high Mg, Fe, Ca and low K, Ti. These basalts show flat REE pattern with Ce negative anomaly (Ce/Ce* 0.73,0.76). Niobium, Ta, Zr, Hf are depleted and Rb, Ba, Th, U, Sr, Pb are enriched with respect to the N-MORB. Both the Sr and Nd isotopes show depleted properties, while the (87Sr/86Sr)i and the ,Nd(t) range from 0.70469 to 0.70488 and 4.6 to 5.3, respectively. All geochemical and isotopic data from the hosting basalt show that it originates from an island arc source. We also report the S isotope data from the massive orebody, and ,34S, change from 1.8, to 5.6,. The S isotope data provide evidence that the sulfur originates from a mixing source between magma and seawater sulfate. We propose that the mafic magma provides the ore-forming metal and some percentage of sulfur, while it also acts as a heat engine which makes the fluids leach the metal from the underlying volcanic rocks. Combining the geological characteristics of the Ashele and geochemical data, and comparing with other Cu-Zn VMS deposits in the world, we propose that Ashele formed in a rifted arc setting. [source] Tectonic Controls on the Formation of the Liwu Cu-rich Sulfide Deposit in the Jianglang Dome, S W ChinaRESOURCE GEOLOGY, Issue 2 2003Dan-Ping Yan Abstract. The Liwu Cu-rich sulfide deposit occurs within the Jianglang dome in the eastern margin of the Tibetan plateau. The dome consists of a core, a middle slab and a cover sequence. The main deposit is hosted in the core with minor ore bodies in the middle slab. The protolith of the core consists of clastic sedimentary rocks with inter-layered volcanic rocks. All of the ore bodies are substantially controlled by an extensional detachment fault system. The ore bodies within the core are distributed along the S2 foliation in the hinge of recumbent fold (D2), whereas ore bodies with en echelon arrangement are controlled by the mylonitic foliation of the lower detachment fault. Ore bodies within the middle slab are oriented with their axes parallel to the mylonitic foliation. Pyrite and pyrrhotite from the ores contain Co ranging from 37 to 1985 ppm, Ni from 2.5 to 28.1 ppm, and Co/Ni ratios from 5 to 71. These sulfides have ,34S values ranging from 1.5 to 7.5 % whereas quartz separates have ,18O values of 11.9 and 14.3 % and inclusion fluid in quartz has ,D value of-88.1 %. These features suggest that the deposit was of hydrothermal origin. Two ore-forming stages are recognized in the evolution of the Jianglang dome. (1) A low-temperature ore-forming process, during the tectonic transport of the upper plate above the lower detachment, and the initial phase of the footwall updom-ing at 192,177 Ma. (2) A medium-temperature ore-forming stage, related to the final structural development of the initial detachment at 131,81Ma. Within the core, the ore bodies of the first stage were uplifted to, or near, the brittle/ductile horizon where the ore-forming metals were re-concentrated and enriched. A denudation stage in which a compressional tectonic event produced eastward thrusting overprinted the previous structures, and finally denuded the deposit. The Liwu Cu-rich sulfide deposit was formed during a regional extensional tectonic event and is defined as a tectono-strata-bound hydrothermal ore deposit. [source] The Elasticity of Demand for Labour in AustraliaTHE ECONOMIC RECORD, Issue 240 2002Philip E. T. Lewis The elasticity of demand for labour at the aggregate level is an important parameter for macroeconomic analysis. In particular, policy issues concerning the impact of wage falls on employment and unemployment hinge on the size of this parameter. It is argued in the present paper that previous work on the elasticity of demand for labour in Australia has been unsatisfactory in a number of ways. A new set of estimates is provided that are derived using a better methodology than before. [source] Structure of DsbC from Haemophilus influenzaeACTA CRYSTALLOGRAPHICA SECTION D, Issue 9 2004Man Zhang Bacterial DsbC proteins are involved in rearranging or reducing mismatched disulfide bonds folding within the periplasm. The X-ray structure of the enzyme from Haemophilus influenzae has been solved and compared with the known structure of the Escherichia coli protein. The proteins act as V-shaped dimers with a large cleft to accommodate substrate proteins. The dimers are anchored by a small N-terminal domain, but have a flexible linker region which allows the larger C-terminal domain, with its reactive sulfhydryls, to clamp down on substrates. The overall folds are very similar, but the comparison shows a wider range of hinge motions than previously thought. The crystal packing of the H. influenzae protein allows the movement of the N-terminal domain with respect to the C-terminal domain through motions in the flexible hinge, generating high thermal parameters and unusually high anisotropy in the crystallographic data. [source] Crystallization and preliminary structure determination of an intact human immunoglobulin, b12: an antibody that broadly neutralizes primary isolates of HIV-1ACTA CRYSTALLOGRAPHICA SECTION D, Issue 1 2001Erica Ollmann Saphire An intact human immunoglobulin with a full-length hinge has been crystallized for the first time in a form in which all of the Ig domains are ordered. The IgG1 antibody b12 is one of only three known monoclonal antibodies described that potently neutralize a broad range of HIV-1 primary isolates. It binds to an epitope overlapping the conserved CD4 binding site on the viral surface antigen gp120. Hexagonal crystals corresponding to space group R32 were grown from 0.8,M ammonium sulfate, with unit-cell parameters a = b = 271.3, c = 175.2,Ĺ and one molecule per asymmetric unit. The crystals diffract to 2.8,Ĺ and a preliminary molecular-replacement solution indicates that all 12 Ig domains of the antibody can be resolved. [source] 3232: Safety and efficacy of femtosecond LASIK with reverse side cutACTA OPHTHALMOLOGICA, Issue 2010F MENICACCI Purpose Laser in situ keratomileusis has several advantages over photorefractive keratectomy when performed properly in appropriate eyes. These include faster visual recovery, less discomfort after surgery, and milder and more predictable wound healing with less risk for haze. Lamellar corneal flap formation is the critical step in successful LASIK surgery. In our study we used femtosecond lasik with 90° hinge and 100 µm thickness flap wi Methods We performed femtosecond lasik in 58 eyes of 30 patients (mean age 35 y.o.) with AMO's IntraLaseÔ FS and STAR S4 IRÔ Excimer Laser System. Criteria for inclusion were spherical myopia of -2 to -8.00 D, hyperopia up to 5 D, astigmatism miopic/hyperopic up to 4.50 D; stable refraction for 2 years; a best-spectacle corrected vision (BSCVA) of at least 20/25 in each eye. Corneal flap thickness was 100µm and hinge position was 90 degrees with reverse 120° side cut. The optical zone of the ablation was from 6.5 to 7 mm, transition zone from 8 to 9 mm. Results Controls were made at 1day, 1 and 3 months. No flap decentration was observed in any case, we had one case of epithelial sloughing and one slightly irregular flap border. Spherical equivalent was within +/- 0.50 D and the cylinder was 0.50 D or less in all patients. Only 5% of patients showed marked discomfort and avversion to light for several days. Conclusion Flap creation is probably the most important step during laser in situ keratomileusis (LASIK), and complications during it can affect the rest of the procedure and cause permanent visual loss. In our exeprience the use of 100µm thickness flap with oblique side cut demonstrated itself to be a safe procedure with a very low complications rate and good refractive results. [source] The evolutionarily conserved residue A653 plays a key role in HERG channel closingTHE JOURNAL OF PHYSIOLOGY, Issue 11 2009Svetlana Z. Stepanovic Human ether-a-go-go- related gene (HERG) encodes the rapid, outwardly rectifying K+ current IKr that is critical for repolarization of the cardiac action potential. Congenital HERG mutations or unintended pharmaceutical block of IKr can lead to life-threatening arrhythmias. Here, we assess the functional role of the alanine at position 653 (HERG-A653) that is highly conserved among evolutionarily divergent K+ channels. HERG-A653 is close to the ,glycine hinge' implicated in K+ channel opening, and is flanked by tyrosine 652 and phenylalanine 656, which contribute to the drug binding site. We substituted an array of seven (I, C, S, G, Y, V and T) amino acids at position 653 and expressed individual variants in heterologous systems to assess changes in gating and drug binding. Substitution of A653 resulted in negative shifts of the V1/2 of activation ranging from ,23.6 (A653S) to ,62.5 (A653V) compared to ,11.2 mV for wild-type (WT). Deactivation was also drastically altered: channels with A653I/C substitutions exhibited delayed deactivation in response to test potentials above the activation threshold, while A653S/G/Y/V/T failed to deactivate under those conditions and required hyperpolarization and prolonged holding potentials at ,130 mV. While A653S/G/T/Y variants showed decreased sensitivity to the IKr inhibitor dofetilide, these changes could not be correlated with defects in channel closure. Homology modelling suggests that in the closed state, A653 forms tight contacts with several residues from the neighbouring subunit in the tetramer, playing a key role in S6 helix packing at the narrowest part of the vestibule. Our study suggests that A653 plays an important functional role in the outwardly rectifying gating behaviour of HERG, supporting channel closure at membrane potentials negative to the channel activation threshold. [source] Failure Mechanism of Deformed Concrete Tunnels Subject to Diagonally Concentrated LoadsCOMPUTER-AIDED CIVIL AND INFRASTRUCTURE ENGINEERING, Issue 6 2009Wei He Based on the experimental findings, an extended discussion is carried out to select a rational compressive model for concrete that represents the dominant failure modes of deformed concrete tunnels. Three main dominant final failure modes are described: structural failure due to the plastic rotation of softening hinges, tensile failure caused by localized cracks, and material failure due to concrete deterioration. A parametric analysis of the material properties of concrete shows that the compressive strength of concrete has a dominant effect on the load-carrying capacity, although the compressive fracture energy of concrete remarkably influences the post-peak deformation behavior of the tunnel. Moreover, the soil pressure, which is regarded as a distributed external load, plays an important role in controlling the final failure modes and the deformation behavior of concrete tunnels. The size effect on the load-carrying capacities of different-sized concrete tunnels is also discussed based on the numerical simulations. [source] Loop Diuretic Therapy, Thiamine Balance, and Heart FailureCONGESTIVE HEART FAILURE, Issue 4 2007Domenic A. Sica MD Thiamine, or vitamin B1, is a water-soluble B complex vitamin that was first discovered in 1910 in the process of exploring how rice bran cured patients of beriberi. Thiamine is not synthesized in humans, therefore its availability for necessary cellular processes hinges on its continual ingestion. The amount of thiamine one needs to ingest to maintain balance is disease state-dependent or medication-dependent. Severe chronic thiamine deficiency can have significant neurologic and cardiac effects, the latter is reflected in a particular type of heart failure called wet beriberi. This form of heart failure clearly benefits from thiamine supplementation. It is unclear, however, whether thiamine supplementation offers any benefit in other forms of heart failure. Despite this, it is not unreasonable for heart failure patients to routinely ingest a thiamine-containing multivitamin; patients using diuretics have an increased urinary excretion of thiamine and thus are at a higher risk for developing thiamine deficiency. The role of thiamine in heart failure, however, remains arguable. [source] Medical Error Identification, Disclosure, and Reporting: Do Emergency Medicine Provider Groups Differ?ACADEMIC EMERGENCY MEDICINE, Issue 4 2006Cherri Hobgood MD Abstract Objectives: To determine if the three types of emergency medicine providers,physicians, nurses, and out-of-hospital providers (emergency medical technicians [EMTs]),differ in their identification, disclosure, and reporting of medical error. Methods: A convenience sample of providers in an academic emergency department evaluated ten case vignettes that represented two error types (medication and cognitive) and three severity levels. For each vignette, providers were asked the following: 1) Is this an error? 2) Would you tell the patient? 3) Would you report this to a hospital committee? To assess differences in identification, disclosure, and reporting by provider type, error type, and error severity, the authors constructed three-way tables with the nonparametric Somers' D clustered on participant. To assess the contribution of disclosure instruction and environmental variables, fixed-effects regression stratified by provider type was used. Results: Of the 116 providers who were eligible, 103 (40 physicians, 26 nurses, and 35 EMTs) had complete data. Physicians were more likely to classify an event as an error (78%) than nurses (71%; p = 0.04) or EMTs (68%; p < 0.01). Nurses were less likely to disclose an error to the patient (59%) than physicians (71%; p = 0.04). Physicians were the least likely to report the error (54%) compared with nurses (68%; p = 0.02) or EMTs (78%; p < 0.01). For all provider and error types, identification, disclosure, and reporting increased with increasing severity. Conclusions: Improving patient safety hinges on the ability of health care providers to accurately identify, disclose, and report medical errors. Interventions must account for differences in error identification, disclosure, and reporting by provider type. 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