bluuebunny/crossref_metadata_2025 huggingface dataset:
Molecular mechanisms for the conversion of zymogens to active proteolytic enzymes
Authors: Khan Amir R. , James Micael N. G.
Published: July 2010

Proteolytic enzymes are synthesized as inactive precursors, or “zymogens,” to prevent unwanted protein degradation, and to enable spatial and temporal regulation of proteolytic activity. Upon sorting or appropriate compartmentalization, zymogen conversion to the active enzyme typically involves limited proteolysis and removal of an “activation segment.” The sizes of activation segments range from dipeptide units to independently folding domains comprising more than 100 residues. A common form of the activation segment is an N‐terminal extension of the mature enzyme, or “prosegment,” that sterically blocks the active site, and thereby prevents binding of substrates. In addition to their inhibitory role, prosegments are frequently important for the folding, stability, and/or intracellular sorting of the zymogen. The mechanisms of conversion to active enzymes are diverse in nature, ranging from enzymatic or nonenzymatic cofactors that trigger activation, to a simple change in pH that results in conversion by an autocatalytic mechanism. Recent X‐ray crystallographic studies of zymogens and comparisons with their active counterparts have identified the structural changes that accompany conversion. This review will focus upon the structural basis for inhibition by activation segments, as well as the molecular events that lead to the conversion of zymogens to active enzymes.
Molecular dynamics simulations of hydrophobic collapse of ubiquitin
Authors: Alonso Darwin.V. , Daggett Valerie
Published: July 2010

Nine nonnative conformations of ubiquitin, generated during two different thermal denaturation trajectories, were simulated under nearly native conditions (62 °C). The simulations included all protein and solvent atoms explicitly, and simulation times ranged from 1‐2.4 ns. The starting structures had α‐carbon root‐mean‐square deviations (RMSDs) from the crystal structure of 4‐12 Å and radii of gyration as high as 1.3 times that of the native state. In all but one case, the protein collapsed when the temperature was lowered and sampled conformations as compact as those reached in a control simulation beginning from the crystal structure. In contrast, the protein did not collapse when simulated in a 60% methanol: water mixture. The behavior of the protein depended on the starting structure: during simulation of the most native‐like starting structures (≤5 Å RMSD to the crystal structure) the RMSD decreased, the number of native hydrogen bonds increased, and the secondary and tertiary structure increased. Intermediate starting structures (5‐10 Å RMSD) collapsed to the radius of gyration of the control simulation, hydrophobic residues were preferentially buried, and the protein acquired some native contacts. However, the protein did not refold. The least native starting structures (10‐12 Å RMSD) did not collapse as completely as the more native‐like structures; instead, they experienced large fluctuations in radius of gyration and went through cycles of expansion and collapse, with improved burial of hydrophobic residues in successive collapsed states.
Solution structure and dynamics of a designed monomeric variant of the lambda Cro repressor
Authors: Mossing Michael C.
Published: July 2010

The solution structure of a monomeric variant of the lambda Cro repressor has been determined by multidimensional NMR. Cro K56[DGEVK] differs from wild‐type Cro by the insertion of five amino acids at the center of the dimer interface. 1H and 15N resonances for 70 of the 71 residues have been assigned. Thirty‐two structures were calculated by hybrid distance geometry/simulated annealing methods using 463 NOE‐distance restraints, 26 hydrogen‐bond, and 39 dihedral‐angle restraints. The root‐mean‐square deviation (RMSD) from the average structure for atoms in residues 3‐60 is 1.03 ± 0.44 Å for the peptide backbone and 1.6 ± 0.73 Å for all nonhydrogen atoms. The overall structure conforms very well to the original design. Although the five inserted residues form a beta hairpin as expected, this engineered turn as well as other turns in the structure are not well defined by the NMR data. Dynamics studies of backbone amides reveal T1/T2 ratios of residues in the α2‐α3, β2‐β3, and engineered turn that are reflective of chemical exchange or internal motion. The solution structure and dynamics are discussed in light of the conformational variation that has been observed in other Cro structures, and the importance of flexibility in DNA recognition.
Trapping of intermediates during the refolding of recombinant human epidermal growth factor (hEGF) by cyanylation, and subsequent structural elucidation by mass spectrometry
Authors: Wu Jiang , YingYang  , Throck Watson J.
Published: July 2010

Human epidermal growth factor (hEGF) contains 53 amino acids and three disulfide bonds. The unfolded, reduced hEGF is allowed to refold under mildly alkaline conditions. The folding is quenched at different time points by adjusting the pH to 3.0 with an acetic acid solution of l‐cyano‐4‐dimethylamino‐pyridinium (CDAP) which traps folding intermediates via cyanylation of free sulfhydryl groups. The mixture of cyanylated intermediates is separated by reversed‐phase HPLC; the fractions collected are identified by mass spectrometry. The disulfide structures of the intermediates are then determined by specific chemical cleavage and mass‐mapping by MALDI‐MS, a novel approach developed in our laboratory. The procedure of quenching and trapping of disulfide intermediates in acidic solution minimizes sulfhydryl‐disulfide exchange, and therefore provides a good measure of folding kinetics and preservation of intermediate species. Our cyanylation methodology for disulfide mapping is simpler, faster, and more sensitive than the more conventional approach.

Among 18 folding intermediates isolated and identified at different time points, disulfide structures of seven well‐populated intermediates, including two non‐native isomers with scrambled disulfide structures, one 2‐disulfide intermediate, and four 1‐disulfide intermediates, have been characterized; most of them possess non‐native disulfide structures.
Genome‐wide analysis of integral membrane proteins from eubacterial, archaean, and eukaryotic organisms
Authors: Wallin Erik , Heijne Gunnar Von
Published: July 2010

We have carried out detailed statistical analyses of integral membrane proteins of the helix‐bundle class from eubacterial, archaean, and eukaryotic organisms for which genome‐wide sequence data are available. Twenty to 30% of all ORFs are predicted to encode membrane proteins, with the larger genomes containing a higher fraction than the smaller ones. Although there is a general tendency that proteins with a smaller number of transmembrane segments are more prevalent than those with many, uni‐cellular organisms appear to prefer proteins with 6 and 12 transmembrane segments, whereas Caenorhabditis elegansandHomo sapienshave a slight preference for proteins with seven transmembrane segments. In all organisms, there is a tendency that membrane proteins either have manytransmembrane segments with short connecting loops or few transmembrane segments with large extra‐membraneous domains. Membrane proteins from all organisms studied, except possibly the archaeon Methanococcus jannaschii, follow the so‐called “positive‐inside” rule; i.e., they tend to have a higher frequency of positively charged residues in cytoplasmic than in extra‐cytoplasmic segments.
Synthesis and evaluation of immobilized androgens for affinity chromatography in the purification of nuclear androgen receptor
Authors: De Larminat Marie‐Anne , Bruchovsky Nicholas , Rennie Paul S. , Lee Sing Ping , Tertzakian Gerald
Published: July 2010

Seven biospecific adsorbents containing immobilized androgens were synthesized: dihydro‐testosterone‐17β‐succinyl agarose, and both the unsubstituted and the 17β‐acetyl derivatives of dihydrotestosterone‐7α‐undecanoyl agarose, testosterone‐7α‐undecanoyl agarose, and 19‐nortestosterone‐7α‐undecanoyl agarose. The retention capacities for nuclear androgen receptor were generally between 40‐80% with little variation in reproducibility; the amount of binding was greatest with dihydrotestosterone‐17β‐succinyl agarose and dihydrotestoster‐one‐17β‐acetoxy‐7α‐undecanoyl agarose. Rapid flow rates were obtained with all gels, and no tendency for decomposition was observed over a period of 1 year. Factors that affected retention included the concentration of immobilized androgen, length of the linker arm, occupation of receptor sites, interval of contact with the gel, and temperature of incubation. Chemical dissociation of androgens from androgen receptor complexes with 0.2 mM mersalyl increased the retention of receptor by dihydrotestosterone‐17β‐succinyl agarose. Two elutants showed promise for the dissociation of gel‐bound receptor: 1) 0.2 mM mersalyl in the presence of 1.5 mg/ml of ovalbumin; 2) 10% (v/v) dimethylformamide:water containing 30 μM [1,2‐3H] dihydrotestosterone and 0.5 M sodium thiocyanate.
The accuracy of transrectal aspiration biopsy of the prostate: An analysis of 452 cases
Authors: Maier U. , Czerwenka K. , Neuhold N.
Published: July 2010

This study compares cytological findings obtained by transrectal aspiration biopsy of the prostate with histological findings obtained by simultaneously performed transperineal punch biopsy. All interventions were performed on outpatients. Complications such as hematuria, urinary infection, or epididymitis occured in 4.4% of the cases, the majority of them being attributed to punch biopsies. Exact correspondence was found in 78.8% of 433 usable specimens, the accuracy for carcinoma amounting to 71.1 %. Specimens cytologically judged either false “negative” or “suspicious” were histologically mostly well‐differentiated (G and G2) carcinomas (96.1%). The value of fine needle biopsy of the prostate as nonstaining diagnostic procedure will be discussed.
Zinc content in the epididymis, vas deferens, prostate, and seminal vesicles of juvenile rhesus monkey (Macaca mulatta): Effect of androgen and Estrogen
Authors: Srivastava Archana , Chowdhury A. R. , Setty B. S.
Published: July 2010

The zinc content in the three segments of the epididymis (caput, corpus, and cauda), vas deferens, seminal vesicles, and prostate of juvenile monkeys was determined by atomic absorption spectrophotometry. Zinc content (μg/gm wet weight) was found to be maximum (328) in the vas deferens; in the other organs it measured in the following order: caput 191, corpus 238, cauda 193, prostate 133 and seminal vesicles 85. In order to investigate the endocrine control of the zinc in these organs, two groups of animals were treated with testosterone propionate (2 mg) or estradiol dipropionate (10μg) once daily for 30 days. In response to androgen, a rise in both concentration and content of zinc was evident only in the prostate. The results further suggested that the prostatic zinc may be under dual hormonal control, but in the epididymis and vas deferens it may be under the influence of estrogen. It is concluded that the hormonal effects on zinc content and growth stimulation in accessory sex organs are quite separate and may be under different hormonal control.
Selectivity and destinations of ethnic minorities leaving the main gateway cities of Estonia
Authors: Tammaru Tiit , Kontuly Thomas
Published: July 2010

Changes in the spatial distribution of minority populations and factors responsible for such changes form an important research topic in the study of the contemporary immigrant societies of Europe and North America. This paper clarifies both the trends and determinants of the spatial redistribution of mainly Russian‐speaking ethnic minorities in Estonia by focusing on out‐migration from the gateway cities or the main minority concentration areas. We use individual data from the 2000 census. The main results show that the dominant flow of migration among members of ethnic minorities is out of the main gateway cities in Estonia, and this trend is very different from the situation during the Soviet period. All of the personal characteristics that measure intentional ties with the majority population and the host country, such as proficiency in Estonian, having an Estonian partner, and Estonian citizenship, exert a positive influence on both leaving these areas and settling in non‐ethnic destinations, while the mere passage of time (generation replacement) has no straightforward influence on minority spatial redistribution. Copyright © 2010 John Wiley & Sons, Ltd.
Synthesis of CdS/TiO2 nanocomposites by using cadmium thiolate derivatives as unimolecular precursors
Authors: Resta Vincenzo , Laera Anna M. , Piscopiello Emanuela , Capodieci Laura , Ferrara Maria C. , Tapfer Leander
Published: July 2010

Highly porous nanocrystalline films of TiO2 sensitized with semiconductor nanocrystals (NCs) are very promising for photovoltaic applications, NCs being more versatile and efficient than organic dyes as sensitizer. In this framework, the visible light absorption of TiO2 can be improved by the superposition of CdS NC absorption band, that is tunable between 2.5 and 5.2 eV. Here, we report on a novel in situ approach for the synthesis of CdS NCs in mesoporous sol–gel TiO2 anatase films by using as starting reagent for CdS, [Cd(SBz)2]MI, where MI represents 1‐methylimidazole. The precursor has been adsorbed into the TiO2 pores and then decomposed at 480 °C, the procedure being studied for TiO2 films with different porosity. The matrices have been investigated by atomic force microscopy. X‐ray diffraction measurements on TiO2 matrix and on the corresponding CdS/TiO2 nanocomposite material revealed a variation of the NCs size of both TiO2 and CdS as a function of the matrix porosity. The optical properties of the TiO2 and CdS/TiO2 have been studied by UV–Vis transmission spectroscopy. CdS/TiO2 nanocomposites, having higher absorption efficiency with respect to TiO2, are suitable as building blocks for 3rd generation solar cell design.
Theoretical study of the CO catalytic oxidation on Au/SAPO‐11 zeolite
Authors: Griffe Beulah , Sierraalta Anibal , Brito Joaquín L.
Published: July 2010

Quantum chemistry calculations were carried out, using ONIOM2 methodology, to investigate the CO adsorption and oxidation on gold supported on Silicoaluminophospates (SAPO) molecular sieves Au/SAPO‐11 catalysts. Two models were studied, one containing one Au atom per site (AuSAPO‐11), and the other with two Au atoms per site (Au2SAPO‐11). The results reveal that the CO adsorption and oxidation are exothermic on Au/SAPO11 with an ΔE of −41.0 kcal/mol and ΔE = −52.0 kcal/mol, for the adsorption and oxidation, respectively. On the Au2SAPO‐11 model, the CO adsorption and oxidation reaction occur, with a ΔE of −29.7 kcal/mol and −52 kcal/mol, respectively. According to our results, the oxidation reaction exhibits an Eley‐Rideal type mechanism with adsorbed CO. The theoretical calculations reveal that this type of material could be interesting to disperse Au and consequently to strengthen its catalytic use for different reactions. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem 110:2573–2582, 2010
Electronic excitation and ionization of hydrogen peroxide–water clusters: Comparison with water clusters
Authors: Ferreira Cristiane , Martiniano Hugo F. M. C. , Cabral Benedito J. Costa , Aquilanti Vincenzo
Published: July 2010

Electronic properties of H2O2(H2O)1–6 and (H2O)1–7 clusters are reported. Emphasis was placed on the changes induced by the presence of hydrogen peroxide on the electronic properties of water aggregates. Theoretical results for excitation energies as well as vertical and adiabatic ionization energies are reported. Excitation energies were calculated with time‐dependent density functional theory and equation‐of‐motion coupled cluster with single and double excitations (EOM‐CCSD). A many‐body energy decomposition scheme recently proposed was coupled to the EOM‐CCSD method making possible an accurate prediction of the first vertical excitation energy of peroxide–water clusters. In comparison with water clusters, our results show that the presence of hydrogen peroxide in water clusters is characterized by a [1.5–1.8] eV red‐shift of the first excitation energy. The first excitation is localized on the HOOH moiety, and no significant dependence of the first excitation energy on the cluster size is observed. The differences between vertical and adiabatic ionization energies for both water and hydrogen peroxide–water clusters reflect the feature that ionization leads to proton transfer and to a significant structural and electronic density reorganization. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2010
Microscopic model of cuprate superconductivity
Authors: Squire Richard H. , March Norman H.
Published: July 2010

We present a model for cuprate superconductivity based on the identification of an experimentally detected “local superconductor” as a charge 2 fermion pairing in a circular, stationary density wave. This wave acts like a highly correlated local “boson” satisfying a modified Cooper problem with additional correlation stabilization relative to the separate right‐ and left‐handed density waves composing it. This local “boson” could be formed in a two‐bound roton‐like manner; it has Fermion statistics. Delocalized superconductive pairing (superconductivity) is achieved by a Feshbach resonance of two unpaired holes (electrons) resonating with a virtual energy level of the bound pair state of the local “boson” as described by the previously discussed Boson‐Fermion‐Gossamer (BFG) model. The spin‐charge order interaction offers a microscopic basis for the cuprateTc's. The spin‐charge interaction correlatesTcwith experimental inelastic neutron and electron Raman scattering is proposed, based on the energy of the virtual bound pair. These and other modifications discussed, suggest a BFG‐based microscopic explanation for the entire cuprate superconductivity dome shape. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2010
Differentiation of the diastereomeric synthetic precursors of isofebrifugine and febrifugine by electrospray ionization tandem mass spectrometry
Authors: Ramanjaneyulu G. S. , Sudhakar N. , Rao B. Venkateswara , Prabhakar S.
Published: July 2010

Febrifugine is an alkaloid with potent antimalarial activity isolated from Dichroa febrifuga and Hydrangea umbellate, and it exists naturally with its diastereomeric component, isofebrifugine. Here we report the differentiation of diastereomeric synthetic precursors of isofebrifugine (1, cis) and febrifugine (2, trans) and a structurally similar model diastereomeric pair without a halogen substituent (3 and 4) by electrospray ionization (ESI) tandem mass spectrometry. Compounds 1–4 contain a tert‐butoxycarbonyl (BOC) substituent, and the collision‐induced dissociation (CID) spectra of the [M+H]+, [M+Na]+ and [M+Li]+ ions of 1–4 include the expected product ions corresponding to the loss of C4H8 (isobutene) and of C5H8O2 (BOC‐H). Loss of C5H8O2 is dominant in cis isomers (1 and 3) and/or loss of C4H8 ions is dominant in trans isomers (2 and 4). The decomposition of [M+H]+ ions shows stereoselectivity in the formation of the [M+H‐(BOC‐H)‐C3H5OBr]+ and [M+H‐(BOC‐H)‐C6H5CH2OH]+ ions. The [M+Cat]+ ions (where Cat = Na or Li) additionally show loss of NaBr and HBr from [M+Cat‐(BOC‐H)]+, and these product ions are constantly more abundant in cis isomers than in trans isomers. The stereoselectivity for the product ion corresponding to the loss of [(BOC‐H)+C3H5OBr] from [M+H]+ ions differs from that from [M+Cat]+ ions. Copyright © 2008 John Wiley & Sons, Ltd.
Air Sparging Pilot Testing Including In‐Well Temperature Measurement
Authors: Eisenbeis John J.
Published: July 2010

Air sparging was pilot tested at a site where a groundwater plume containing cis‐1,2‐dichloroethene (cis‐DCE), vinyl chloride (VC) and arsenic resulted from landfill operations. In addition to the commonly used methods for estimating air sparging zone of influence (ZOI), in‐well temperature was monitored using sensitive thermocouples and data loggers at several monitoring wells of various screened intervals during the test. Following 42 days of pilot testing, the downgradient monitoring well samples were below maximum contaminant levels (MCLs)for all contaminants of concern, VC and dissolved arsenic were below detection limits (0.5 and 10 milligrams per liter [μg/L], respectively) in all of the downgradient monitoring wells.

The ZOI monitoring results indicated that at some locations use of mounding data may overestimate the ZOI when the temperature data suggest that no sparged air was entering the well screen. Therefore, monitoring in‐well temperature may provide additional useful information for estimating air sparging ZOI and is more indicative of air pathways than other monitoring methods. In addition, the temperature data were valuable for selecting a pulse frequency and duration to optimize groundwater mixing.
Trends In Regulatory Acceptance Of Risk‐Based Cleanup Goals And Natural Attenuation For Site Closure
Authors: Downey Douglas C. , Benson Leigh A. , Taffinder Sam A.
Published: July 2010

Since 1994, there has been a significant regulatory shift toward risk‐based cleanup standards based on the site‐specific risk of the more toxic and mobile compounds; namely, benzene, ethyl benzene, toluene, and xylene (BTEX). This regulatory shift has been accompanied by a growing acceptance of natural attenuation as an important component of petroleum site remediation. This article briefly reviews regulatory progress toward risk‐based remediation and describes the successful application of risk‐based corrective actions (RBCAs) at two fuel contaminated sites on Air Force installations. By developing site‐specific cleanup goals, and combining natural attenuation, source reduction, and land use controls, innovative risk‐based closure plans have been implemented on these sites.
Screening Technology Trains for DNAPL Remediation
Authors: Kloeber Jack M. , Papatyi Anthony F. , Deckro Richard F. , Parnell Gregory S. , Jackson Jack A.
Published: July 2010

The Department of Energy (DOE) is conducting a Comprehensive Environmental Response, Compensation and Liability Act (CERCLA) mandated Remedial Investigation/Feasibility Study for a site contaminated with Dense Non‐Aqueous Phase Liquid (DNAPL) pollutants. Three key efforts were a hydrogeological modeling approach, the generation of feasible sequences of technologies, and the screening of alternative technologies. This research uses a decision analysis process to provide a quantitative assessment of the candidate technologies. Decision analysis modeling was used to gain insight into each sequence of technologies. Sensitivity analysis was also conducted to assess the impact of key assumptions. The results provided the DOE with an objective and traceable rationale for screening and reducing all of the potential technology combinations to 58 technology combinations and a method for identifying the top scoring combinations. The approach has wide applicability to similar CERCLA remediation efforts.
The Use of Oxygen Release Compound for the Accelerated Bioremediation of Aerobically Degradable Contaminants: The Advent of Time‐Release Electron Acceptors
Authors: Koenigsberg Stephen S. , Sandefur Craig A.
Published: July 2010

Oxygen Release Compound (ORC®) is a patented formulation of intercalated magnesium peroxide that releases oxygen slowly when hydrated. ORC treatment represents a “low intensity” approach to site remediation. It provides a simple, passive, low‐cost and long‐term acceleration of aerobic natural attenuation and has been shown to cost‐effectively reduce time to site closure. ORC is now a proven technology as evidenced by its five years of use on over 5,000 sites in 50 states and 11 countries, and the existence of a full body of independent, peer reviewed literature on its performance.

The first applications of ORC were for the treatment of benzene, toulene, ethylbenzene, and xylene (BTEX) and other light petroleum hydrocarbon fractions. Use has now expanded to the treatment of heavier fractions such as heating oil and some of the Polycyclic aromatic hydrocarbons (PAHs). More recently. ORC has been used to bioremediate the highly mobile and problematic gasoline oxygenate methyl tertiary butyl ether (MTBE) and has been applied to sites impacted with nitroaromatics, chloroaromatics, and some of the lower‐order chlorinated hydrocarbons that can be treated aerobically—most notably vinyl chloride.

Since ORC is an insoluble powder, it can be packaged in material composed of a specially designed filter fabric. These “filter socks” are then contacted with contaminated groundwater via an array of wells or trenches. ORC can also be mixed directly with water to form a slurry for permanent injection applications in the saturated zone or dispersed in powdered form for the in‐situ or ex‐situ treatment of soil. A broad array of treatment points, in which ORC slurry is backfilled or injected, can be implemented with low‐cost, small‐bore push‐point technologies to directly treat dissolved phase plumes and moderate levels of sorbed contaminants. Powder or slurry is traditionally used in the remediation of residual contamination at the bottom of contaminated soil excavations. © 1999 John Wiley & Sons, Inc.
The Use of Hydrogen Release Compound for the Accelerated Bioremediation of Anaerobically Degradable Contaminants: The Advent of Time‐Release Electron Donors
Authors: Sandefur Craig A. , Koenigsberg Stephen S.
Published: July 2010

Hydrogen Release Compound (HRC®) is a simple, passive, low‐cost, and long‐term option for the anaerobic bioremediation of chlorinated hydrocarbons (CHs) via reductive dehalogenation. Applications to the remediation of other compounds, such as MTBE and perchlorate, that are anaerobically degradable by other reductive mechanisms, are in progress. HRC should be viewed as a tool for the acceleration of natural attenuation at sites that would otherwise require high levels of capital investment and operating expense.

HRC is a proprietary, food‐quality, polylactate ester that, upon being deposited into the subsurface, slowly degrades to lactic acid. Lactic acid is then metabolized to hydrogen, which in turn drives the reductive dechlorination of CHs. This has been demonstrated effectively in the laboratory and in the field. HRC can be manufactured as a moderately flowable, injectable material, or as a thicker, implantable hard gel, to facilitate localized treatment and passive barrier designs. HRC is best utilized for the remediation of dissolved phase plumes and the associated hydrophobically sorbed contaminant. The use of HRC is not appropriate for use on free‐phase DNAPL unless the total mass to be remediated is within the scope of economic feasibility in comparison to alternative treatments.

Evidence suggests there is competition between reductive dehalogenators and methanogens in which the methanogens compete for the use of hydrogen in the conversion of carbon dioxide to methane. Some researchers believe that a low concentration of hydrogen favors the reductive dehalogenators and starves out the methanogens. The objective, therefore, is to keep hydrogen concentrations low. The time‐release feature of HRC, which is based on the hydrolysis rate of lactic acid from the ester and the subsequent lag time to hydrogen conversion, facilitates this objective. HRC, therefore, becomes a passive form of accelerated natural attenuation, in contrast to the more capital‐and management‐intensive alternatives now available. Laboratory and field results are presented, the latter expanding on the first uses of HRC by various members of the engineering and consulting firm community. © 1999 John Wiley & Sons, Inc.
Randomized greedy matching
Authors: Dyer Martin , Frieze Alan
Published: July 2010

We consider a randomized version of the greedy algorithm for finding a large matching in a graph. We assume that the next edge is always randomly chosen from those remaining. We analyze the performance of this algorithm when the input graph is fixed. We show that there are graphs for which this Randomized Greedy Algorithm (RGA) usually only obtains a matching close in size to that guaranteed by worst‐case analysis (i.e., half the size of the maximum). For some classes of sparse graphs (e.g., planar graphs and forests) we show that the RGA performs significantly better than the worst‐case. Our main theorem concerns forests. We prove that the ratio to maximum here is at least 0.7690…, and that this bound is tight.
Probabilistic analysis of a parallel algorithm for finding the lexicographically first depth first search tree in a dense random graph
Authors: Dyer Martin , Friezet Alan
Published: July 2010

We describe an O((log n)2) time parallel algorithm, using n processors, for finding the lexicographically first depth first search tree in the random graph G n, p, with p fixed. The problem itself is complete for P, and so is unlikely to be efficiently parallelizable always.
Evaluating the ability of different characterization parameters to describe the surface of fried foods
Authors: Moreno María Carolina , Bouchon Pedro , Brown Christopher A.
Published: July 2010

The objective of this work is to identify surface topography characterization parameters that are capable of discriminating the surfaces of different fried foods. Three fried food model systems with clearly different surfaces were formulated from vital wheat gluten, native wheat starch, and potato flakes. The surfaces were measured with a scanning laser microscope (SLM), and the ability of several parameters to discriminate between them was tested. Two conventional parameters, the root mean square roughness (Sq) and the surface Kurtosis (Sku), were calculated, along with parameters derived from area‐scale fractal analysis: smooth–rough crossover (SRC), fractal dimension, and relative area as a function of scale. The coefficient of variation (COV) of Sq, Sku, and SRC and fractal dimension of different sizes of measurement regions were calculated for the surface of the roughest product in order to specify a measurement region that would be sufficiently large to be representative. The size of the representative region was found to be 25 mm2. Among the parameters evaluated in this study, the most reliable parameter for discriminating the surfaces of fried foods is the relative area calculated from area‐scale fractal analysis. SCANNING 32: 212–218, 2010. © 2010 Wiley Periodicals, Inc.
On optimum illumination for channeling experiments
Authors: Eades J. A.
Published: July 2010

In experiments in which channeling effects are important, it may be desirable simultaneously to maximize the current, minimize the area of the sample that is illuminated, and, in particular, minimize the divergence of the beam. The ability to meet these incompatible conditions is limited by the source brightness. The optimum illumination in such cases is achieved by focusing the illumination on the sample. This result is, perhaps, counterintuitive and in conflict with frequently given advice “to get more parallel illumination, defocus the beam”.
Measurement of specimen charging in scanning electron microscopy with a kelvin probe
Authors: Rettig R. , Kässens M. , Reimer L.
Published: July 2010

A vibrating Kelvin probe in form of a platinum wire loop is used to measure the surface potential Us on electron‐irradiated free‐floating metal and insulator specimens as a function of electron energy E. This allows an accurate measurement of the critical electron energy E2 for no charging. At energies below E2, the positive charging increases with decreasing energy to Us=2–5 eV at E=0.5 keV and switching off the collector bias of the Everhart‐Thornley detector. A two‐to threefold increase of Us is observed when the bias is switched on. For E > E2, the strong increase of a negative surface potential can be measured. Insulating films free‐supported on a conductive substrate show a steep decrease to small positive and negative Us when the film thickness becomes lower than the electron range at a critical energy E3 > E2. At insulating specimen the temporal decrease of charging can be measured when the electron beam is switched off.
Observations of human corneal epithelium by tandem scanning confocal microscope
Authors: Tomii Satoshl , Klnoshtta Shigeru
Published: July 2010

We applied the tandem scanning confocal microscope (TSCM) to 30 healthy human corneas of 3 normal volunteers and 27 patients with cataract and retinal detachment to observe normal corneal epithelial cells in vivo. All corneas were normal under slit lamp microscopic examination. The superficial and basal epithelial cells close to the basal lamina in the central cornea were recorded on videotape and analyzed by a computer‐assisted digitizer. The mean cell areas of superficial cells exposed at the surface and basal cells at the horizontal section were 624 ± 109 μm2 and 66 ± 5 μm2, respectively. The ratio of superficial to basal mean cell area was 11.0 ± 4.5. TSCM was thus useful in evaluating the relationship between superficial and basal cells in human corneal epithelium in vivo.
The scanning optical microscope (extracts on near‐field microscopy)—from a 1975 report
Authors: Kompfner R. , Sheppard C. J. R. , Walsh D. , Choudhury A. , Gannaway J. N. , Hale P. G.
Published: July 2010

The following consists of extracts concerning near‐field microscopy from a Progress Report prepared in April 1975 as Oxford University Engineering Laboratory Report No. 1883/77, describing work initiated by the late Professor R. Kompfner. Preliminary experimental work on near‐field microscopy is outlined, and a theory for contrast formation is presented.
Infrared scanning for biomedical applications
Authors: Mil'Shtein S.
Published: July 2010

The great interest in using infrared imaging for biological and medical applications is motivated by the harmless interaction of small doses of infrared radiation with biological objects and by the technical ability of infrared digital cameras to generate, produce, store, and display the resultant images in situ. In this study, we review the state of the art of infrared (IR) imaging in comparison with well established medical imaging techniques such as ultrasound and x‐rays. We demonstrate for the first time that by using IR transmitted light, one can observe bones, tendons, cartilages, and other tissues. The IR long‐focus scanning microscope was built to allow two modes of scanning. The first mode is when illumination of a biological object is performed at the same angle of view with different IR wavelengths λ. The second mode is when, for fixed wavelength λ, scanning of the source of light around the object is performed. We discuss the special image processing methods and potential applications of the new scanner for medical diagnostics. This novel, low‐cost IR imaging system (hardware and software) allows one to scan biological objects such as human arms, legs, palms, and fingers to differentiate tissues, tendons, muscles, ligaments, blood vessels, bones, and cartilages. Some of these objects cannot be detected by conventional x‐rays.
An accurate approximation for the highly efficient sampling of polar scattering angle of electron elastic single‐scattering events
Authors: Pasciak Alexander S. , Ford John R.
Published: July 2010

In single‐event Monte Carlo electron transport simulations, elastic scattering events dominate the changes in electron trajectories due to collisions. Classically, the polar scattering angle due to an elastic collision can be sampled efficiently from the screened Rutherford cross section. However, the screened Rutherford cross section fails for both high Z materials and when the incident electron energy becomes too low. Alternatively, improved simulation accuracy for electrons in all energy ranges and through all materials may be obtained by sampling directly from differential data derived from partial‐wave‐expansion method (PWEM) calculations based on theoretical atomic potential models. While sampling directly from wave calculations will yield simulation results to the best known physical accuracy, it comes at the cost of simulation time. This is due to a sampling process that is typically more involved when compared with using the screened Rutherford cross section. In this work we present a relationship capable of reproducing the moments of the differential cross section derived from PWEM calculations, resulting in good preservation of forward and backscattering peaks. The relationship is directly invertible and is as easily sampled as the Rutherford cross section. Most important, the data presented in this paper in combination with this relationship produce Monte Carlo simulation results which are comparable with those using the exact differential cross section from PWEM calculations for elements Z = 1 to 96 and for incident electron energies from 300,000 down to 50 eV.
Interactive spatio‐spectral analysis of three‐dimensional mass‐spectral (3DxMS) chemical images
Authors: Reichenbach Stephen E. , Tian Xue , Lindquist Robert , Tao Qingping , Henderson Alex , Vickerman John C.
Published: July 2010

Emerging technologies for chemical imaging provide high‐resolution three‐dimensional (3D) surveys with high‐precision mass spectrometry (MS), promising to open unprecedented vistas for understanding complex phenomena such as cellular metabolism. However, there are critical challenges in transforming the large, complex, multidimensional, multispectral data sets into useful chemical information for biological research and other applications. This paper describes new informatics for advanced interactive spatio‐spectral analysis of three‐dimensional mass‐spectral (3DxMS) chemical images. The technical challenges for interactive informatics are rapid access to large datasets, visualization of 3D hyperspectral images, and pattern recognition for spatio‐spectral mapping. This paper describes an effective compression method for time‐of‐flight secondary ion mass spectrometry (ToF‐SIMS) data that provides rapid spatial‐spectral access; a framework for 3DxMS visualization that supports multiple views with multiple layers of information; and a suite of pattern recognition tools for spatio‐spectral drawing, clustering, and classification. Copyright © 2010 John Wiley & Sons, Ltd.
Epilogue: mapping future research on burnout and health
Authors: Shirom Arie
Published: July 2010

The lack of aetiologic clarity regarding burnout–health associations represents a major impediment towards progress in understanding burnout's role in employee occupational health. What are some of the promising research directions on burnout and health that emerged from this Special Issue? Emphasizing aspects of physical health, this concluding paper attempts to respond to the aforementioned question. Additionally, I delineated several possible ways in which future research could better serve health‐care policy‐makers and health‐care practitioners. Copyright © 2009 John Wiley & Sons, Ltd.
Visualizing and exploring profiles with calling context ring charts
Authors: Moret Philippe , Binder Walter , Villazón Alex , Ansaloni Danilo , Heydarnoori Abbas
Published: July 2010

Calling context profiling is an important technique for analyzing the performance of object‐oriented software with complex inter‐procedural control flow. The Calling Context Tree (CCT) is a common data structure that stores dynamic metrics, such as CPU time, separately for each calling context. As CCTs may comprise millions of nodes, there is a need for a condensed visualization that eases the localization of performance bottlenecks. In this article, we discussCalling Context Ring Charts(CCRCs), a compact visualization for CCTs, where callee methods are represented in ring segments surrounding the caller's ring segment. In order to reveal hot methods, their callers, and callees, the ring segments can be sized according to a chosen dynamic metric. We describe two case studies where CCRCs help us to detect and fix performance problems in applications. A performance evaluation also confirms that our implementation can efficiently handle large CCTs. Copyright © 2010 John Wiley & Sons, Ltd.
The potential of (−)‐o‐[11C]methylvesamicol for diagnosing cholinergic deficit dementia
Authors: Shiba Kazuhiro , Nishiyama Shingo , Tsukada Hideo , Ishiwata Kiichi , Kawamura Kazunori , Ogawa Kazuma , Mori Hirofumi
Published: July 2010

(−)‐o‐Methylvesamicol ((−)‐OMV) exhibited in vitro a high affinity for a vesicular acetylcholine transporter (VAChT) (Ki, 6.7 nM), and (−)‐o‐[11C]methylvesamicol [(−)‐[11C]OMV] exhibited appropriate kinetics and bound mainly to VAChTs in the rat brain. In this study, the in vivo distribution and kinetics of (−)‐[11C]OMV were evaluated in comparison with [11C]SA4503 in disability model monkeys produced by selectively destroying the p75NTR‐positive cells in the right hemisphere of the brain using positron emission tomography. Time–activity curves of (−)‐[11C]OMV showed peaks within 20 min in regions rich in acetylcholine transporters (AchT). (−)‐[11C]OMV binding in the ipsilateral cortex to the lesion was significantly reduced by 22.0% ± 6.7% when compared with that in the contralateral region. The decrease (19.3% ± 2.2%) in (−)‐[11C]OMV binding in the ipsilateral temporal cortex to the lesion was greater than that (7.4% ± 4.6%) of [11C]SA4503. These results suggested that (−)‐[11C]OMV may be useful in the study of dementia characterized by degeneration of the cholinergic neurotransmitter system. Synapse 63:167–171, 2009. © 2008 Wiley‐Liss, Inc.
Zinc Coordination Complex for use in Uniform ZnS Microflowers Synthesis
Authors: Mi Liwei , Han Minle , Li Zhen , Yang Fengling , Shen Changyu , Zheng Zhi
Published: July 2010

Uniform snowball zinc sulfide (ZnS) microflowers with nanosheet covering were synthesized using the one step reaction of zinc coordination compounds with thiourea at 160 °C for 24 h. X‐ray single crystal diffraction, electron microscopy, energy‐dispersive X‐ray spectrometry, and X‐ray diffraction were used to characterize the products. The flower‐like ZnS crystals may have some application in catalyst or solar cell devices. This work is also expected to be applied in the fabrication of other transition metal sulfide crystals with special morphology.
A review of reported litigation against English health trusts for the treatment of children in orthopaedics: Present trends and suggestions to reduce mistakes
Authors: Atrey A. , Nicolaou N. , Katchburian M. , Norman-Taylor F.
Published: July 2010

Purpose

Large scale databases that offer a reflection of clinical negligence are rare. By assessing commonly occuring cases of negligence, we hope to highlight areas where pediatric orthopedic care might be improved. One such database is the National Health Service Litigation Authority, which deals with claims brought against all health trusts in England. By collating their data we aimed to highlight areas of commonly occurring clinical negligence and then suggest ways to avoid similar happening again.

Method

We reviewed all cases pertaining to pediatric orthopedic claims between 1995 to 2006 as provided by the NHSLA.

Results

Of those considered in our study (341), by far the most common cause of litigation is missed or incorrectly diagnosed injuries/ conditions—accounting for 57% of all cases. 44% of those are upper limb injuries, mainly fractures around the elbow. Misdiagnosed disorders of the hip such as hip dysplasia and SCFE also represent a frequent reason for litigation (11%). Other common causes are poor plaster application and removal (7.3%) and non-surgical site specific errors such as chemical burns from skin prep.

Conclusion

Although specific to the English system, these findings are likely to mirror that found in other countries. Highlighting these commonly occurring errors, better education of doctors in targeted areas and due care in simple procedures may have significant improvement of child orthopedic care.
Transient and permanent gene transfer into the brain of the teleost fish medaka (Oryzias latipes) using human adenovirus and the Cre‐loxP system
Authors: Suehiro Yuji , Kinoshita Masato , Okuyama Teruhiro , Shimada Atsuko , Naruse Kiyoshi , Takeda Hiroyuki , Kubo Takeo , Hashimoto Mitsuhiro , Takeuchi Hideaki
Published: July 2010

In this study, we demonstrated that human type‐5 adenovirus infected the brain of the teleost fish, medaka (Oryzias latipes), in vivo. Injection of adenoviral vector into the mesencephalic ventricle of medaka larvae induced the expression of reporter genes in some parts of the telencephalon, the periventricular area of the mesencephalon and diencephalon, and the cerebellum. Additionally, the Cre‐loxP system works in medaka brains using transgenic medaka carrying a vector containing DsRed2, flanked by loxP sites under control of the β‐actin promoter and downstream promoterless enhanced green fluorescent protein (EGFP). We demonstrated that the presence of green fluorescence depended on injection of adenoviral vector expressing the Cre gene and confirmed that EGFP mRNA was transcribed in the virus‐injected larvae.
Studies of Health Executives in Canada: A Review and Comparison
Authors: Storch Janet L.
Published: July 2010

There are a limited number of national studies of health executives in Canada and the few that do exist are not well known to the average executive. In this article, these studies are reviewed, and the demographic findings of three more recent studies are compared in respect to hospital CEOs. Three potential trends are noted: an upward shift in level of education of CEOs, with a steady but not increasing representation of M.H.A./M.H.S.A. graduates; a decreasing length of tenure in hospital CEO positions with evidence of recent turnover in many CEO positions; and a continuing male dominance in hospital CEO positions, It is suggested that the implications of these trends should be considered as they apply to the education of health executives and as they affect the effectiveness of healthcare.
Les services de santé offerts en français en Ontario
Authors: Deroche Francine C.M.
Published: July 2010

Le système ontarien des soins de santé est affecté par la Loi sur les services en français promulgée en 1986. Une analyse de l'implantation des services de santé en français est effectuée selon trois critères: la permanence, la qualité et l'accessibilité des services. L'analyse soulève des questions concernant: l'évaluation et la création d'une demande pour des services; la pénurie de ressources humaines; les priorités du système des soins de santé; les caractéristiques des services de haute qualité; et l'influence du milieu politique et économique. La prestation des services de santé offerts en français, qui sont à la fois permanents, accessibles et de haute qualité, constitue un défi pour un système de soins de santé dans un état précaire.
An Evaluation of Program Management: The West Park Hospital Experience
Authors: Morris Kathleen , Stuart Neil , Monaghan Barry , Alton Leslie
Published: July 2010

Program management as a way to structure hospital management has been attracting growing interest. Numerous hospitals are introducing it. West Park Hospital was one of the first hospitals to adopt program management in 1991 and mount a rigorous evaluation of the new approach, one which relied on external evaluators. This article reviews the emergence of program management in the hospital sector and reports on the evaluation of West Park's experience.
The Chaplain's Role in Bioethical Decision-Making
Authors: Simmonds Anne L.
Published: July 2010

With advances in medical technology, difficult questions of “What should be done?” and “Who should decide?” are a daily occurrence in hospitals. This paper reports the results of a survey of Canadian chaplains with respect to their involvement in bioethical decision-making. The survey suggests that chaplains make a significant contribution to discussion and resolution of bioethical dilemmas. Using a case study, the paper elaborates on the chaplain's role in bioethical decision-making, and indicates how such participation can influence both cost containment and risk management.