bluuebunny/crossref_metadata_2025_split huggingface dataset:
Practical Implementation of Satellite Navigation Safety Assessment
Authors: Magny Jean Pierre 
Published: July 2002

This, and the following three papers, were first presented at GNSS 2000, the Third European
Symposium on Global Navigation Satellite Systems held in Edinburgh, Scotland from 1st to
4th May 2000.This paper presents the methodology and a practical implementation approach to perform
GNSS Safety Assessment and Certification with due consideration of the satellite navigation
system users. It places Galileo GNSS in a total system that includes vehicles, on-board
equipment, crews and traffic controllers and defines the necessary organisation for
implementing safety analyses right from the early design phases of navigation systems. Civil
aviation has very demanding requirements based on objectives for air navigation safety. It
is much better organised on a worldwide basis than other GNSS users and is considered in
this paper as the leading study case. Some methods are then proposed to build a bridge
between all user organisations and to set up a common approach to certification.
The Law Relating to Satellite Navigation and Air Traffic
Management Systems – A View From The South Pacific
Authors: Murray Kim 
Published: July 2002

This is an updated and revised version of a paper originally presented to a CNS/ATM
Forum of representatives from the States, airlines and air traffic service provider
organisations of the Pacific region meeting in Sydney, Australia on 16 April 1998. The
Forum was organised under the auspices of the Australian and New Zealand Divisions
of the Royal Aeronautical Society.There are many legal issues involved in the provision and use of new technology based on
satellite navigation and communications in Air Traffic Management Systems. These include
aspects of international space law, international air law and domestic state law. Spanning
these aspects are regional provisions and the role of ICAO. This paper considers these issues
with particular reference to the Pacific region, which is in the lead in adopting the new
technology, and concludes that much of the existing law applies, but that new law is
also required if the legal framework is to keep pace with introduction of the new
technology.
Identification and treatment of anaemia in older patients
Authors: Casey MC , Murphy PT 
Published: July 2002

Anaemia is the most common haematological problem of older patients. Given the
heterogenous nature of this group, with an age span of over 30 years, the reported
prevalence of anaemia is, not surprisingly, quite variable. However, a large survey
from the UK has reported an overall prevalence of anaemia of 20.1% in elderly
men and 13.7% in elderly women.The types and causes of anaemia differ between elderly and younger patients. Anaemia of chronic disease becomes the commonest cause of anaemia in the older age group and reflects the increased incidence of chronic inflammation and malignancy in later years. Iron deficiency anaemia is commonly seen and due to gastrointestinal blood loss. Furthermore dietary deficiencies not only of iron, but also of folate, protein and ascorbic acid can all precipitate anaemia in the many elderly subjects who live in poor socio-economic conditions. Pernicious anaemia, as with other autoimmune conditions, is also encountered more commonly in the elderly than in the younger population. Malignant blood disorders with associated anaemia, such as myelodysplasia and leukaemia, become more frequent with advancing age.
Study of the influence of oxygen on structural perfection of silicon single crystals by high-resolution X-ray diffraction and infrared absorption measurements
Authors: Lal Krishan , Ramanan R. R. , Bhagavannarayana G. 
Published: July 2002

High-resolution X-ray diffractometry, absolute integrated intensity (ρ) measurements, diffuse X-ray scattering (DXS) and infrared (IR) absorption techniques were used to investigate the influence of oxygen on the structural perfection of high purity (resistivity of the order of 4 kΩ cm) float zone (FZ) grown (111) silicon single crystals. A multicrystal diffractometer set in (+,-,-,+) geometry, with Mo Kα1radiation, was employed. From the infrared measurements, the oxygen concentration in the sample was determined to be 1.3 × 1017 atoms cm^{-3}. High-resolution X-ray diffraction curves of the as-grown crystal had half-widths of ∼11 arcsec; the ρ value was 3.5 × 10^{-5} rad. To incorporate oxygen in a controlled manner into the specimens, they were annealed under dry oxygen ambient for 8 h in the temperature range 573–1373 K (in eight steps). Up to 723 K there was no appreciable change in oxygen content or in the degree of perfection. Annealing at temperatures (AT) > 873 K resulted in considerable increases in the oxygen content, as well as significant improvements in the degree of perfection. For example, as the level of oxygen increased from 1.3 × 1017to 3.6 × 1017 atoms cm^{-3} for A_T=873 K, the values of half-widths and ρ decreased to ∼7 arcsec and 2.4 × 10^{-5} rad, respectively. However, annealing above 1273 K produced deterioration in lattice perfection. DXS measurements showed remarkable changes in the nature of point defects and their clusters with change inAT. Up to A_T=973 K, the defects were predominantly vacancy clusters. However, withATin the range 1073–1273 K, the predominent defects were isolated interstitials. Further increase inATled to interstitial cluster formation, which deteriorated the lattice perfection. This study clearly demonstrates that oxygen concentration in the range ∼3 × 1017to 13 × 1017atoms cm^{-3} leads to significant improvement in structural perfection of silicon single crystals.
Purification, crystallization and preliminary X-ray diffraction data from selenomethionine glycinamide ribonucleotide synthetase
Authors: Weaver Todd M. , Wang Weiru , Ealick Steven E. 
Published: July 2002

In this study, the overexpression, purification and crystallization of selenomethionine (SeMet) incorporated glycinamide ribonucleotide synthetase (GAR-syn) from Escherichia coli are reported. The overexpression of SeMet GAR-syn was placed under the control of the isopropylthio-β-galactoside (IPTG) inducible T7 RNA-polymerase system. The newly developed construct contained a removable histidine tag on the amino terminus of GAR-syn, which allowed rapid purification using metal-chelate chromatography techniques. The SeMet GAR-syn crystals were grown by hanging-drop vapor diffusion and belong to the space group P212121 with unit-cell parameters a = 56.2, b = 62.4 and c = 129.8 Å and a single monomer in the asymmetric unit. The crystals diffract to 1.6 Å resolution and have led to the determination of multiple-wavelength anomalous diffraction phases to 2.2 Å resolution.
Crystallization, X-ray diffraction and preliminary structure analysis of Mycobacterium tuberculosis chaperonin 10
Authors: Roberts Michael M. , Coker Alun R. , Fossati Gianluca , Mascagni Paolo , Coates Anthony R. M. , Wood Steve P. 
Published: July 2002

The Mycobacterium tuberculosis chaperonin 10 (Mtcpn10) has been crystallized by the sitting-drop vapour-diffusion method. The crystals belong to the monoclinic space group P21, with unit-cell parameters a = 76.5, b = 87.9, c = 124.4 Å, β = 106.8°. X-ray diffraction data were collected to 2.8 Å. The self-rotation function and the molecular-replacement solution show that the asymmetric unit contains a dimer of heptamers related by twofold non-crystallographic symmetry. The two heptamers interact through interleaving flexible loops in a similar fashion to M. leprae and Gp31 cpn10. In addition to its role in protein folding, Mtcpn10 has unique effects on the growth of host cells and is a major immunogen in tuberculosis infections. The structure determination will permit the analysis of the amino acids identified as important for the protein-folding and cell-signalling activity of Mtcpn10.
Structure of the RWJ-51084–bovine pancreatic β-trypsin complex at 1.8 Å
Authors: Recacha Rosario , Carson Mike , Costanzo Michael J. , Maryanoff Bruce , DeLucas Lawrence J. , Chattopadhyay Debasish 
Published: July 2002

The three-dimensional structure of bovine pancreatic trypsin complexed with the inhibitor RWJ-51084 has been determined at 1.8 Å resolution. These crystals belong to the trigonal space group P3121, with unit-cell parameters a = b = 53.43, c = 107.76 Å. The refined R and R
free values are 0.175 and 0.237, respectively. The carbonyl group bonded to the benzothiazole group of the inhibitor is covalently linked to the hydroxyl O atom of Ser195, forming a tetrahedral intermediate hemiketal structure. The other carbonyl O atom of the inhibitor forms a hydrogen bond with the Gln192 side-chain amide group. The benzothiazole group is oriented with the aromatic N atom of RWJ-51084 accepting a hydrogen bond from His57 NE2. The arginine side chain of the inhibitor extends into the deep and narrow pocket of the S1 specificity site of trypsin, forming a network of hydrogen bonds.
Structure of acutolysin-C, a haemorrhagic toxin from the venom of Agkistrodon acutus, providing further evidence for the mechanism of the pH-dependent proteolytic reaction of zinc metalloproteinases
Authors: Zhu Xue-yong , Teng Mai-kun , Niu Li-wen 
Published: July 2002

The structure of acutolysin-C, a haemorrhagic zinc metalloproteinase from the venom of Agkistrodon acutus, has been analyzed and refined at 2.2 Å resolution. The space group of the crystal is P212121, with unit-cell dimensions a = 46.84, b = 49.52, c = 95.34 Å. One molecule was found in each asymmetric unit. The phasing problem was solved by the molecular-replacement program AMoRe. Crystallographic refinement was performed using X-PLOR, leading to final R and free R factors of 0.176 and 0.272, respectively. The residue sequence of acutolysin-C was determined mainly by electron density. No density was found for the first residue at the N-terminus and the last two residues at the C-terminus, which was also the case for most other P-I class snake-venom metalloproteinases (SVMPs). Acutolysin-C has two highly conserved characteristic sequences His142-Glu143-X-X-His146-X-X-Gly149-X-X-His152 and Cys162-Ile163-Met164. The enzyme has three disulfide bridges: Cys117–Cys195, Cys157–Cys179 and Cys159–Cys162. The entire structure shows good agreement with that of other reported P-I class SVMPs and has two subdomains with a cleft in which one catalytic zinc ion is localized. However, the local conformation (especially the disulfide configurations), the coordination of the catalytic water molecules and some residue side chains differ compared with other P-I class SVMPs. The proteolytic activities of SVMPs are sensitive to the pH value. The molecular superpositions around the proteolytic active sites of all the P-I class SVMP crystal structures show that the distances between the zinc ion and its ligands are not correlated with the crystallization pH values, although the contact distances between the catalytic water molecule and the O atoms of the Glu143 carboxylate group in the neutral and weakly alkaline structures are shorter than those in weakly acidic structures, and the closer the crystallization pH value of one enzyme is to its optimal activity pH value, the shorter the contact distances. Overall, all P-I class SVMPs have similar conformations in the active-site cleft. The size of the active site is not correlated with the crystallization pH values or the proteolytic activities. The disulfide bridge Cys117–Cys195 is conserved in all crystal structures of P-I class SVMPs, whereas the conformation and number of disulfide bridges in the C-terminal subdomain differ. Acutolysin-C has no structural calcium ion, which may not affect the proteolytic activity or haemorrhagic activity directly.
Initiating a structural study of 2-keto-3-deoxy-6-phosphogluconate aldolase from Escherichia coli
Authors: Buchanan Louise V. , Mehta Nupur , Pocivavsek Luka , Niranjanakumari S. , Toone Eric J. , Naismith James H. 
Published: July 2002

2-Keto-3-deoxy-6-phosphogluconate aldolase (KDPG aldolase, E.C. 4.1.2.14) is a member of the pyruvate/phosphoenolpyruvate aldolase family. It is also a synthetically useful enzyme, capable of catalyzing the stereoselective aldol addition of pyruvate to a range of unnatural electrophilic substrates. The recombinant protein was purified by a two-step HPLC protocol involving anion-exchange and hydrophobic chromatography. Dynamic light-scattering experiments indicated the protein to be monodisperse. Crystals were obtained using the sitting-drop vapour-diffusion method, with PEG 6K as precipitant. Diffraction data were collected on a frozen crystal to a resolution of 2.26 Å on station PX9.6 at the Daresbury synchrotron. The crystal belongs to space group P212121, with unit-cell parameters a = 53.2, b = 77.9, c = 146.8 Å.
A new approach for indexing powder diffraction data based on whole-profile fitting and global optimization using a genetic algorithm
Authors: Kariuki Benson M. , Belmonte Scott A. , McMahon Malcolm I. , Johnston Roy L. , Harris Kenneth D. M. , Nelmes Richard J. 
Published: July 2002

This paper describes a new technique for indexing powder diffraction data. The lattice parameters (unit-cell dimensions) {a,b,c,α,β,γ} define the parameter space of the problem, and the aim is to find the optimal lattice parameters for a given experimental powder diffraction pattern. Conventional methods for indexing consider the measured positions of a limited number of peak maxima, whereas this new approach considers the whole powder diffraction profile. This new strategy offers several advantages, which are discussed fully. In this approach, the quality of a given set of lattice parameters is determined from the profile R-factor, R
wp, obtained following a Le Bail-type fit of the intensity profile. To find the correct lattice parameters (i.e. the global minimum in R
wp), a genetic algorithm has been used to explore the R
wp(a,b,c,α,β,γ) hypersurface. (Other methods for global minimization, such as Monte Carlo and simulated annealing, may also be effective.) Initially, a number of trial sets of lattice parameters are generated at random, and this `population' is then allowed to evolve subject to well defined evolutionary procedures for mating, mutation and natural selection (the fitness of each member of the population is determined from its value of R
wp). Examples are presented to demonstrate the success and underline the potential of this new approach for indexing powder diffraction data.
Abstract: Electron beam deposition of alumina to rf modulated steel substrates
Authors: Komiya Souji , Mizuno Masayasu 
Published: July 2002

Radiofrequency modulation has been applied in an ion plating process for an insulator material. Alumina was evaporated from a 270° bent electron beam source. Heat dissipation at the substrate surface with respect to deposition rate and rf power input was measured by a calorimetric method. Films deposited at various conditions of substrate temperature and rf power were assessed. The effect of rf modulation was observed on appearance of films formed at low temperatures (220°C) and on fractured sections at high temperatures (410°C).
For films formed at 280°, 360°, and 410°C on either steel or molybdenum sheets, no differences in pin hole, adhesion, and film composition can be detected due to the effect of rf modulation.
Detection of Resistance to Amphotericin B in
Candida
Isolates by Using Iso-Sensitest Broth
Authors: Cuenca-Estrella Manuel , Dı́az-Guerra Teresa M. , Mellado Emilia , Rodrı́guez-Tudela Juan L. 
Published: July 2002

ABSTRACT

A major limitation of the National Committee for Clinical Laboratory Standards M27-A methodology is reliable detection of amphotericin B (AMB) resistance. The results obtained by using Iso-Sensitest, a synthetic medium, to detect AMB resistance were analyzed and compared with those obtained with RPMI and antibiotic medium 3 (AM3). The ability to detect AMB resistance with RPMI is not enhanced by using a higher inoculum, glucose supplementation at a final concentration of 20 g/liter, spectrophotometric reading, or 24 h of incubation time. Testing using AM3 and an inoculum of 10
3
CFU/ml detects resistance. Identification of resistant isolates is not improved by glucose supplementation, changes in reading method, or changes in incubation time. However, the use of AM3 as assay medium and an inoculum of 10
5
CFU/ml did not allow detection of AMB resistance. Testing using Iso-Sensitest medium appears to be similar to AM3 in detecting resistance. The most pronounced discrimination is achieved by testing in Iso-Sensitest supplemented with glucose and spectrophotometric reading after 24 h of incubation. The reproducibility of MIC testing was greatest for Iso-Sensitest-based procedures. Use of Iso-Sensitest produces both highly reproducible MICs and reliable identification of AMB-resistant
Candida
isolates.
Inhibition of a Glucose-Limited Sequencing Fed-Batch Culture of
Salmonella enterica
Serovar Enteritidis by Volatile Fatty Acids Representative of the Ceca of Broiler Chickens
Authors: van der Wielen Paul W. J. J. , Biesterveld Steef , Lipman Len J. A. , van Knapen Frans 
Published: July 2002

ABSTRACT

The effects of concentrations of volatile fatty acids on an anaerobic, glucose-limited, and pH-controlled growing culture of
Salmonella enterica
serovar Enteritidis were studied. Suddenly increasing volatile fatty acids to the concentrations representative of the ceca of 15-day-old broiler chickens caused washout of serovar Enteritidis. In contrast, a sudden increase to the volatile fatty acid concentrations representative of the ceca of younger broiler chickens caused a reduction in the biomass but not washout. Gradually increasing volatile fatty acids caused a gradual decrease in the biomass of serovar Enteritidis. We conclude that the concentrations of volatile fatty acids present in the ceca of broilers with a mature microflora can cause washout of serovar Enteritidis in an in vitro system mimicking cecal ecophysiology.
Modulation of B-Cell Proliferative Response by a Soluble Extract ofNippostrongylus brasiliensis
Authors: Ehigiator Humphrey N. , Stadnyk Andrew W. , Lee Timothy D. G. 
Published: July 2002

ABSTRACTWe and others have previously shown that nematodes or nematode products can stimulate or inhibit the generation of lymphocyte responses, suggesting that nematodes exert diverse effects on the developing immune responses of their host. In this study we examined the immunomodulatory effect of a soluble extract ofNippostrongylus brasiliensis(adult worm homogenate [AWH]) on B-cell responsiveness. We found that the extract inhibited the proliferation of B cells to lipopolysaccharide (LPS) stimulation in a dose-dependent manner. This effect was specific to B cells, since the extract did not inhibit T-cell proliferation to concanavalin A or anti-CD3 stimulation. The data presented here confirm that the extract is not toxic to B cells. We present evidence that the active factor is proteinaceous in nature and that the inhibitory activity is restricted to the adult stage ofNb. The extract does not appear to interfere with early activation events since it can be added up to 48 h after LPS stimulation, and it inhibited responses to phorbol myristate acetate and ionomycin. Furthermore, the proliferation of B cells to other activators was also inhibited by AWH. This observation shows that the inhibitory activity of AWH is not restricted to LPS-mediated B-cell proliferation. We present evidence that, in the absence of accessory cells, the inhibitory effect of the extract was ablated. This observation shows that the activity of AWH is not mediated directly on B cells but is mediated via the production of negative signals from accessory cells (macrophages), which affect a downstream pathway required by all B-cell activators tested. These effects on B-cell and accessory cell function are likely to have a significant effect on the outcome of infections experienced concurrently.
Neisseria gonorrhoeaePorin Modifies the Oxidative Burst of Human Professional Phagocytes
Authors: Lorenzen Dirk R. , Günther Dirk , Pandit Jasmine , Rudel Thomas , Brandt Ernst , Meyer Thomas F. 
Published: July 2002

ABSTRACTA hallmark of infection with the gram-negative bacteriumNeisseria gonorrhoeaeis the local infiltration and subsequent activation of polymorphonuclear neutrophils. Several gonococcal outer membrane proteins are involved in the interaction with and the activation of these phagocytes, including gonococcal porin, the most abundant protein in the outer membrane. Previous work suggests that this porin plays a role in various cellular processes, including inhibiting neutrophils activation and phagosome maturation in professional phagocytes. Here we investigated the ability of porin to modify the oxidative metabolism of human peripheral blood neutrophils and monocytes in response to particulate stimuli (including live gonococci) and soluble agents. The activation of the oxidative metabolism was determined by chemiluminescence amplified with either luminol or lucigenin. We found that treatment of the phagocytes with porin inhibits the release of reactive oxygen species measured as luminol-enhanced chemiluminescence in response to zymosan, latex particles, and gonococci. The engulfment of these particles was not, however, affected by porin treatment. Similar effects of porin on the chemiluminescence response were observed in cytochalasin B-treated neutrophils exposed to the soluble chemotactic peptideN-formylmethionyl-leucyl-phenylalanine. This indicates that porin selectively inhibits granule fusion with those cellular membranes that are in direct contact with porin, namely, the phagosomal and plasma membranes. This porin-induced downregulation of oxidative metabolism may be a potent mechanism by which gonococci modulate oxygen-dependent reactions by activated phagocytes at inflammation sites.
TonB Is Required for Intracellular Growth and Virulence ofShigella dysenteriae
Authors: Reeves Stephanie A. , Torres Alfredo G. , Payne Shelley M. 
Published: July 2002

ABSTRACTTo assess the importance of TonB-dependent iron transport systems to growth ofShigellain vivo, atonBmutant ofShigella dysenteriaewas isolated and tested in cultured cells. ThetonBmutant invaded epithelial cells, but did not form plaques in confluent monolayers of Henle cells, indicating an inability of this mutant to spread from cell to cell. The rate of intracellular multiplication of thetonBmutant was reduced significantly compared to that of the wild type. The loss of virulence in thetonBmutant was not due to loss of either Shu or Ent, the TonB-dependent systems which allow for transport of heme and ferrienterobactin, respectively. AshuAmutant lacking the outer membrane receptor for heme, anentBmutant defective in enterobactin synthesis, and ashuA entBdouble mutant each were able to invade cultured cells, multiply intracellularly, and form wild-type plaques. The ability ofS. dysenteriaeto access iron during intracellular growth was assessed by flow cytometric analysis of an iron- and Fur-regulatedshuA-gfpreporter construct. Low levels of green fluorescent protein expression in the intracellular environment were observed in all strains, indicating that iron is available to intracellular bacteria, even in the absence of TonB-dependent iron transport. The failure of thetonBmutant to grow well in an iron-replete intracellular environment suggests that TonB plays a role in addition to heme- and siderophore-mediated iron acquisition in vivo, and this function is required for the intracellular growth and intercellular spread ofS. dysenteriae.