bluuebunny/crossref_metadata_2025 huggingface dataset:
Localization of UvrA and Effect of DNA Damage on the Chromosome of
Bacillus subtilis
Authors: Smith Bradley T. , Grossman Alan D. , Walker Graham C.
Published: July 2002

We found that the nucleotide excision repair protein UvrA, which is involved in DNA damage recognition, localizes to the entire chromosome both before and after damage in living
Bacillus subtilis
cells. We suggest that the UvrA
2
B damage recognition complex is constantly scanning the genome, searching for lesions in the DNA. We also found that DNA damage induces a dramatic reconfiguration of the chromosome such that it no longer fills the entire cell as it does during normal growth. This reconfiguration is reversible after low doses of damage and is dependent on the damage-induced SOS response. We suggest that this reconfiguration of the chromosome after damage may be either a reflection of ongoing DNA repair or an active mechanism to protect the cell’s genome. Similar observations have been made in
Escherichia coli
, indicating that the alteration of chromosome structure after DNA damage may be a widespread phenomenon.
Construction and Synchronization of
dnaA
Temperature-Sensitive Mutants of
Streptomyces
Authors: Lee Li-Fong , Yeh Shun-Hua , Chen Carton W.
Published: July 2002

Temperature-sensitive mutants of
Streptomyces
defective in initiation of chromosome replication were created by in vitro site-directed mutagenesis in the
dnaA
gene followed by gene replacement. When they were shifted to 39°C replication in the mutants ceased in about 90 min but resumed on return to 30°C. This allowed manipulations to achieve replication synchronization.
Evaluation of 5′ Nuclease Assay for Detection of
Actinobacillus pleuropneumoniae
Authors: Angen Øystein , Jensen Jannie , Lavritsen Dorte T.
Published: July 2002

Sequence detection by the 5′ nuclease TaqMan assay uses online detection of internal fluorogenic probes in closed PCR tubes. Primers and probe were chosen from a part of the
omlA
gene common to all serotypes of
Actinobacillus pleuropneumoniae
, which gave an amplicon of 92 bp. The test was evaluated with 73 lung isolates and 120 tonsil isolates of
A. pleuropneumoniae
as well as with a collection of reference strains. By using a

C
t

value (cycle number in which the fluorescence exceeds the threshold defined by the software) of 30 as the cutoff limit, the 5′ nuclease assay represents a test with 100% sensitivity and 100% specificity. A high degree of reproducibility of the test was demonstrated. If samples with

C
t

values of ≤30 are considered positive, the detection limit of the assay was 1 CFU/reaction tube, corresponding to a 10-fold higher number of DNA templates. After cycle 30, nonspecific reactions appeared when testing dilutions of DNA templates or pure cultures of
A. pleuropneumoniae
, as well as when testing tonsil scrapings from specific-pathogen-free herds. The diagnostic sensitivity, as evaluated with 586 tonsil scrapings from animals infected with
A. pleuropneumoniae
, is the same level as that of a PCR test based on the
omlA
gene described previously. The 5′ nuclease assay represents a fast method for species-specific detection and identification of
A. pleuropneumoniae
in pure and mixed cultures. The evaluation shows, however, that a

C
t

value cutoff limit of ≤30 must be chosen in order to obtain reliable results. The investigation emphasizes that a thorough evaluation of the criteria used to define a positive test result is necessary.
Great Diversity of Group A Rotavirus Strains and High Prevalence of Mixed Rotavirus Infections in India
Authors: Jain Vivek , Das Bimal K. , Bhan Maharaj K. , Glass Roger I. , Gentsch Jon R. ,   the Indian Strain Surveillance Collaborating Laboratories
Published: July 2002

We previously observed a marked diversity of rotavirus strains and a high prevalence of the uncommon serotype G9 in a small survey of rotavirus strains collected from six centers in India. In the present study, we characterized a larger collection of strains from children hospitalized with severe diarrhea in seven Indian cities between 1996 and 1998. A total of 287 strains were G and P genotyped by reverse transcription-PCR, and some were further characterized by electropherotyping and subgrouping. Of the four strains common globally, three were found in only 43% of samples (P[8], G1, 15%; P[4], G2, 22%; P[8], G4, 6%), whereas G9 strains made up 17% of the total. Three different G9 strains were present: a P[8], G9 strain, which displayed the long electropherotype and subgroup II VP6 specificity, and two P[6], G9 strains, one with the long electropherotype and subgroup II specificity and the other with the short electropherotype and subgroup I specificity. Marked diversity was observed among strains collected from different cities and collected over time. Of the 253 strains that were fully typed, 54 (21%) had a mixed G or P genotype. Serotype G2 strains were detected more often in infections caused by single strains than in mixed infections (
P
< 0.05), whereas serotype G1 strains were found more often in mixed infections than in infections caused by single strains (
P
< 0.05). The diversity of rotavirus strains and the high prevalence of mixed infections confirm trends reported earlier and help to better characterize the strains of rotavirus circulating in India. Vaccines under development should clearly target G9 strains, and G9 should be included as one of the common global serotypes.
Mannosidase Production by Viridans Group Streptococci
Authors: Homer K. A. , Roberts G. , Byers H. L. , Tarelli E. , Whiley R. A. , Philpott-Howard J. , Beighton D.
Published: July 2002

The production of mannosidase activity by all currently recognized species of human viridans group streptococci was determined using an assay in which bacterial growth was dependent on the degradation of the high-mannose-type glycans of RNase B and subsequent utilization of released mannose. RNase B is an excellent substrate for the demonstration of mannosidase activity since it is a glycoprotein with a single glycosylation site which is occupied by high-mannose-type glycoforms containing five to nine mannose residues. Mannosidase activity was produced only by some members of the mitis group (
Streptococcus mitis, Streptococcus oralis, Streptococcus gordonii, Streptococcus cristatus, Streptococcus infantis, Streptococcus parasanguinis
, and
Streptococcus pneumoniae
) and
Streptococcus intermedius
of the anginosus group. None of the other species within the salivarius and mutans groups or
Streptococcus peroris
and
Streptococcus sanguinis
produced mannosidase activity. Using matrix-assisted laser desorption ionization time-of-flight mass spectrometry, it was demonstrated that the Man
5
glycan alone was degraded while Man
6
to Man
9
, which contain terminal α(1→2) mannose residues in addition to the α(1→3), α(1→6), and β(1→4) residues present in Man
5
, remained intact. Investigations on mannosidase production using synthetic (4-methylumbelliferone- or
p
-nitrophenol-linked) α- or β-mannosides as substrates indicated that there was no correlation between degradation of these substrates and degradation of the Man
5
glycan of RNase B. No species degraded these α-linked mannosides, while degradation of the β-linked synthetic substrates was restricted to strains within the
Streptococcus anginosus, S. gordonii
, and
S. intermedius
species. The data generated using a native glycoprotein as the substrate demonstrate that mannosidase production within the viridans group streptococci is more widely distributed than had previously been considered.
Toward Standardization of Epstein-Barr Virus DNA Load Monitoring: Unfractionated Whole Blood as Preferred Clinical Specimen
Authors: Stevens Servi J. C. , Pronk Inge , Middeldorp Jaap M.
Published: July 2002

Epstein-Barr virus (EBV) DNA load monitoring in peripheral blood has been shown to be a useful tool for the diagnosis of aberrant EBV infections. In the present study we compared the relative diagnostic values of EBV DNA load monitoring in unfractionated whole blood and simultaneously obtained serum or plasma samples from Burkitt's lymphoma (BL) patients, transplant recipients, human immunodeficiency virus (HIV)-infected individuals, and infectious mononucleosis (IM) patients by a quantitative competitive PCR (Q-PCR). The EBV DNA load in BL patients was mainly situated in the cellular blood compartment (up to 4.5 × 10
6
copies/ml). EBV DNA loads in unfractionated whole blood and parallel serum samples showed no correlation. In transplant recipients, IM patients, and HIV-infected patients, the EBV burden in the circulation was almost exclusively restricted to the cellular blood compartment, because serum or plasma samples from these patients yielded negative results by Q-PCR, despite high viral loads in corresponding whole-blood samples. A 10-fold more sensitive but qualitative
Bam
HI-W-repeat PCR occasionally revealed the presence of EBV at <2,000 copies of EBV DNA per ml of serum. Spiking of 100 copies of EBV DNA in samples with negative Q-PCR results excluded the presence of inhibitory factors in serum or plasma that influenced the Q-PCR result. Serum samples from all populations were often positive for β-globin DNA, indicating cell damage in vivo or during serum preparation. We conclude that serum is an undesirable clinical specimen for EBV DNA load monitoring because it omits the presence of cell-associated virus and uncontrolled cell lysis may give irreproducible results or overestimation of the DNA load. Unfractionated whole blood is strongly preferred since it combines all blood compartments that may harbor EBV and it best reflects the absolute viral burden in the patient's circulation.
Comparison of Variable Number Tandem Repeat and IS
6110
-Restriction Fragment Length Polymorphism Analyses for Discrimination of High- and Low-Copy-Number IS
6110 Mycobacterium tuberculosis
Isolates
Authors: Barlow Rachael E. L. , Gascoyne-Binzi Deborah M. , Gillespie Stephen H. , Dickens Anne , Qamer Shabnam , Hawkey Peter M.
Published: July 2002

The present study was designed to evaluate the use of variable number tandem repeat (VNTR) and IS
6110
-restriction fragment length polymorphism (RFLP) analyses in combination as a two-step strategy for discrimination (as measured by the Hunter-Gaston Discrimination Index [HGDI]) of both high- and low-copy-number IS
6110 Mycobacterium tuberculosis
isolates compared to IS
6110
-RFLP alone with an unselected collection of isolates. Individually, IS
6110
-RFLP fingerprinting produced six clusters that accounted for 69% of the low-copy-number IS
6110
isolates (five clusters) and 5% of the high-copy-number IS
6110
isolates (one cluster). A total of 39% of all the isolates were clustered (HGDI = 0.97). VNTR analysis generated a total of 35 different VNTR allele profile sets from 93 isolates (HGDI = 0.938). Combining IS
6110
-RFLP analysis with VNTR analysis reduced the overall percentage of clustered isolates to 29% (HGDI = 0.988) and discriminated a further 27% of low-copy-number isolates that would have been clustered by IS
6110
-RFLP alone. The use of VNTR analysis as an initial typing strategy facilitates further analysis by IS
6110
-RFLP, and more importantly, VNTR analysis subdivides some IS
6110
-RFLP-defined clusters containing low- and single-copy IS
6110
isolates.
O-Antigen Diversity among
Acinetobacter baumannii
Strains from the Czech Republic and Northwestern Europe, as Determined by Lipopolysaccharide-Specific Monoclonal Antibodies
Authors: Pantophlet Ralph , Nemec Alexandr , Brade Lore , Brade Helmut , Dijkshoorn Lenie
Published: July 2002

O-antigen-specific monoclonal antibodies (MAbs) are currently being generated to develop an O-serotyping scheme for the genus
Acinetobacter
and to provide potent tools to study the diversity of O-antigens among
Acinetobacter
strains. In this report,
Acinetobacter baumannii
strains from the Czech Republic and from two clonal groups identified in Northwestern Europe (termed clones I and II) were investigated for their reactivity with a panel of O-antigen-specific MAbs generated against
Acinetobacter
strains from various species. The bacteria were characterized for their ribotype, biotype, and antibiotic susceptibility and the presence of the 8.7-kb plasmid pAN1. By using the combination of these typing profiles, the Czech strains could be classified into four previously defined groups (A. Nemec, L. Janda, O. Melter, and L. Dijkshoorn, J. Med. Microbiol. 48:287–296, 1999): two relatively homogeneous groups of multiresistant strains (termed groups A and B), a heterogeneous group of other multiresistant strains, and a group of susceptible strains. O-antigen reactivity was observed primarily with MAbs generated against
Acinetobacter calcoaceticus
and
Acinetobacter baumannii
strains. A comparison of reaction patterns confirmed the previously hypothesized clonal relationship between group A and clone I strains, which are also similar in other properties. The results show that there is limited O-antigen variability among strains with similar geno- and phenotypic characteristics and are suggestive of a high prevalence of certain
A. baumannii
serotypes in the clinical environment. It is also shown that O-antigen-specific MAbs are useful for the follow-up of strains causing outbreaks in hospitals.
Differentiation of Metronidazole-Sensitive and -Resistant Clinical Isolates of
Helicobacter pylori
by Immunoblotting with Antisera to the RdxA Protein
Authors: Latham Stephanie R. , Owen Robert J. , Elviss Nicola C. , Labigne Agnès , Jenks Peter J.
Published: July 2002

Antimicrobial resistance in
Helicobacter pylori
is a serious and increasing problem, and the development of rapid, reliable methods for detecting resistance would greatly improve the selection of antibiotics used to treat gastric infection with this organism. We assessed whether detection of the RdxA protein could provide the basis for determining the susceptibility of
H. pylori
to metronidazole. In order to raise polyclonal antisera to RdxA, we cloned the
rdxA
gene from
H. pylori
strain 26695 into the commercial expression vector pMAL-c2, purified the resultant fusion protein by affinity chromatography, and used this recombinant RdxA preparation to immunize rabbits. We then used this specific anti-RdxA antibody to perform immunoblotting on whole bacterial cell lysates of 17 metronidazole-sensitive and 27 metronidazole-resistant clinical isolates of
H. pylori
. While a 24-kDa immunoreactive band corresponding to the RdxA protein was observed in all metronidazole-sensitive strains, this band was absent in 25 of 27 resistant isolates. Our results indicate that testing for the absence of the RdxA protein would identify the majority of clinical isolates that will respond poorly to metronidazole-containing eradication regimens and have implications for the development of assays capable of detecting metronidazole resistance in
H. pylori
.
Semiautomation of Multilocus Sequence Typing for the Characterization of Clinical Isolates of
Neisseria meningitidis
Authors: Clarke S. C. , Diggle M. A. , Edwards G. F. S.
Published: July 2002

The Scottish Meningococcus and Pneumococcus Reference Laboratory (SMPRL) provides a national service for the laboratory confirmation of meningococcal and pneumococcal disease in Scotland. Part of this service includes the serogrouping of meningococcal isolates followed by typing and subtyping. The procedures for this are labor-intensive but important for the identification of linked cases and the surveillance of disease so that effective public health measures can be taken. However, different strains of meningococci, such as those within the electrophoretic type 37 complex, occurring during case clusters of disease are now indistinguishable by current methods. The SMPRL has started using multilocus sequence typing (MLST) as a routine method for the characterization of isolates of
Neisseria meningitidis
. MLST produces nucleotide sequence data of seven housekeeping genes providing results that are useful for public health management. However, the method is laborious and time-consuming and therefore lends itself towards automation. The SMPRL therefore developed a semiautomated method for MLST using a 96-well format liquid handler and an automated DNA sequencer. Semiautomated MLST is now provided as a reference service for Scotland. This work describes the methodology required for the characterization of
N. meningitidis
and highlights its usefulness for public health intervention.
Molecular Evidence of
Helicobacter cinaedi
Organisms in Human Gastric Biopsy Specimens
Authors: Peña J. A. , McNeil K. , Fox J. G. , Versalovic J.
Published: July 2002

One hundred twenty-six urease-negative gastric biopsy specimens were evaluated for the presence of
Helicobacter
genus-specific 16S ribosomal DNA (rDNA) and
H. pylori
-specific
glmM
DNA sequences by PCR. The species specificity of the
glmM
PCR assay was demonstrated, as
H. pylori
was the only
Helicobacter
species that yielded the expected
glmM
amplicon. Most urease-negative specimens (118 of 126 specimens) lacked
Helicobacter
DNA. However, 8 of 126 urease-negative specimens contained
Helicobacter
16S rDNA. In order to identify the
Helicobacter
species present in urease-negative gastric biopsy specimens, 16S rDNA amplicons were cloned and sequenced. Sequence comparisons were performed by analyses of the sequences in public sequence databases. Two samples contained 16S rDNA that was identified as
H. cinaedi
with 100% identity and that spanned approximately 400 bp (398 and 398 bp, respectively). In contrast, multiple differences (97% identity; 390 of 398 bp) were observed with
H. pylori
16S rDNA in this region. This finding was verified by sequencing an overlapping 537-bp fragment within the 5′ portion of 16S rDNA. Although the clinical findings were consistent with
H. pylori
infection (e.g., duodenal ulcer disease), rapid urease testing and DNA sequence analyses suggested the presence of
H. cinaedi
organisms and the absence of
H. pylori
in two human antral biopsy specimens. This study represents the first report of an enteric urease-negative helicobacter in the human stomach. Although these organisms were previously associated with extragastric infections, the roles of these organisms in the pathogenesis of chronic gastritis or peptic ulcer disease remain unclear.
Comparative Analysis of Titers of Antibody against Measles Virus in Sera of Vaccinated and Naturally Infected Japanese Individuals of Different Age Groups
Authors: Itoh Masae , Okuno Yoshinobu , Hotta Hak
Published: July 2002

The anti-measles virus (MV) antibody titers in the sera of vaccinees and naturally infected individuals of different age groups were measured to help assess the efficacy of the current MV vaccination in Japan. Neutralizing (NT) antibody titers induced by vaccination were 2
3.2
times lower than those induced by natural infection and declined significantly by age 20. The once-decreased NT antibody titers of the vaccinees increased 2
3.6
times during their twenties to titers comparable to those of naturally infected individuals of the same age, implying the possible occurrence of natural infection in vaccinees with decreased anti-MV immunity. Although the current field strains in Japan, types D3 and D5, were reported to differ antigenically from each other and from vaccine strains (type A) to some extent, as demonstrated by different reactivities to monoclonal antibodies, the sera of vaccinees neutralized the two types of field strains and the vaccine strain with the same efficiency. This result suggests that the current vaccine strain would be suitable to elicit protection against types D3 and D5, as long as viral antigenicity is concerned. However, when compared at given hemagglutination inhibition titers, NT antibody titers of vaccinees were 2
1.1
to 2
3.2
times lower than those of naturally infected individuals, suggesting a qualitative difference(s) of anti-MV antibodies between the two groups. It should be emphasized that protective immunity induced by the one-dose vaccination currently implemented in Japan may not be strong enough to ensure lifelong immunity. A two-dose vaccination program with higher vaccination coverage needs to be considered in order to effectively control measles in Japan.
Cross-Reactive T-Helper Responses in Patients Infected with Different Subtypes of Human Immunodeficiency Virus Type 1
Authors: Leandersson Ann-Charlotte , Gilljam Gustav , Fredriksson Malin , Hinkula Jorma , Alaeus Annette , Lidman Knut , Albert Jan , Bratt Göran , Sandström Eric , Wahren Britta
Published: July 2002

Immunization with a recombinant glycoprotein 160 envelope immunogen derived from a virus of genetic subtype B induced strong specific T-helper cell responses in asymptomatic human immunodeficiency virus (HIV) carriers infected with subtypes B to G. This indicates that the HIV-specific T-helper immunity, which is the basis for development of antibodies and cytotoxic T lymphocytes, can be improved by both homologous and heterologous antigens. It also suggests that a particular immunogen can be effective against many different HIV strains.
Delivery of Multiple Epitopes by Recombinant Detoxified Adenylate Cyclase ofBordetella pertussisInduces Protective Antiviral Immunity
Authors: Fayolle Catherine , Osickova Adriana , Osicka Radim , Henry Thomas , Rojas Marie-Jésus , Saron Marie-Françoise , Sebo Peter , Leclerc Claude
Published: July 2002

CyaA, the adenylate cyclase toxin fromBordetella pertussis, can deliver its N-terminal catalytic domain into the cytosol of a large number of eukaryotic cells and particularly into professional antigen-presenting cells. We have previously identified within the primary structure of CyaA several permissive sites at which insertion of peptides does not alter the ability of the toxin to enter cells. This property has been exploited to design recombinant CyaA toxoids capable of delivering major histocompatibility complex (MHC) class I-restricted CD8+T-cell epitopes into antigen-presenting cells and to induce specific CD8+cytotoxic T-lymphocyte (CTL) responses in vivo. Here we have explored the capacity of the CyaA vector carrying several different CD8+T-cell epitopes to prime multiple CTL responses. The model vaccine consisted of a polyepitope made of three CTL epitopes from lymphocytic choriomeningitis virus (LCMV), the V3 region of human immunodeficiency virus gp120, and chicken ovalbumin, inserted at three different sites of the catalytic domain of genetically detoxified CyaA. Each of these epitopes was processed on delivery by CyaA and presented in vitro to specific T-cell hybridomas. Immunization of mice by CyaA toxoids carrying the polyepitope lead to the induction of specific CTL responses for each of the three epitopes, as well as to protection against a lethal viral challenge. Moreover, mice primed against the vector by mock CyaA or a recombinant toxoid were still able to develop strong CTL responses after subsequent immunization with a recombinant CyaA carrying a foreign CD8+CTL epitope. These results highlight the potency of the adenylate cyclase vector for induction of protective CTL responses with multiple specificity and/or broad MHC restriction.
Involvement of Cellular Double-Stranded DNA Break Binding Proteins in Processing of the Recombinant Adeno-Associated Virus Genome
Authors: Zentilin Lorena , Marcello Alessandro , Giacca Mauro
Published: July 2002

Unlike postmitotic tissues in vivo, transduction of cultured cells is poor with recombinant adeno-associated virus (rAAV). The ability of rAAV to transduce cells is greatly enhanced by a variety of agents that induce DNA damage and is elevated in cells defective in the ataxia telangiectasia gene product (ATM), showing increased genomic instability. Here we show that DNA double-stranded break (DSB) repair pathways are involved in the regulation of rAAV transduction efficiency. By quantitative chromatin immunoprecipitation, we found that Ku86 and Rad52 proteins associate with viral DNA inside transduced cells. Both proteins are known to competitively recognize hairpin structures and DNA termini and to promote repair of DSBs, the former by facilitating nonhomologous end joining and the latter by initiating homologous recombination. We found that rAAV transduction is increased in Ku86-defective cells while it is inhibited in Rad52 knockout cells. These results suggest that binding of Rad52 to the rAAV genome might be involved in processing of the vector genome through a homologous recombination pathway.
DNA Vaccination with the Human Immunodeficiency Virus Type 1 SF162ΔV2 Envelope Elicits Immune Responses That Offer Partial Protection from Simian/Human Immunodeficiency Virus Infection to CD8
+
T-Cell-Depleted Rhesus Macaques
Authors: Cherpelis S. , Shrivastava I. , Gettie A. , Jin X. , Ho D. D. , Barnett S. W. , Stamatatos L.
Published: July 2002

DNA immunization of macaques with the SF162ΔV2 envelope elicited lymphoproliferative responses and potent neutralizing antibodies. The animals were depleted of their CD8
+
T lymphocytes and then challenged intravenously with SHIV162P4. Compared to unvaccinated animals, the vaccinated macaques had lower peak viremia levels, rapidly cleared plasma virus, and showed delayed seroconversion.
Intracellular Trafficking of Adeno-Associated Virus Vectors: Routing to the Late Endosomal Compartment and Proteasome Degradation
Authors: Douar Anne-Marie , Poulard Karine , Stockholm Daniel , Danos Olivier
Published: July 2002

The early steps of adeno-associated virus (AAV) infection involve attachment to a variety of cell surface receptors (heparan sulfate, integrins, and fibroblast growth factor receptor 1) followed by clathrin-dependent or independent internalization. Here we have studied the subsequent intracellular trafficking of AAV particles from the endosomal compartment to the nucleus. Human cell lines were transduced with a recombinant AAV (rAAV) carrying a reporter gene (luciferase or green fluorescent protein) in the presence of agents that affect trafficking. The effects of bafilomycin A
1
, brefeldin A, and MG-132 were measured. These drugs act at the level of endosome acidification, early-to-late endosome transition, and proteasome activity, respectively. We observed that the transducing virions needed to be routed as far as the late endosomal compartment. This behavior was markedly different from that observed with adenovirus particles. Antiproteasome treatments with MG-132 led to a 50-fold enhancement in transduction efficiency. This effect was accompanied by a 10-fold intracellular accumulation of single-stranded DNA AAV genomes, suggesting that the mechanism of transduction enhancement was different from the one mediated by a helper adenovirus, which facilitates the conversion of the rAAV single-stranded DNA genome into its replicative form. MG-132, a drug currently in clinical use, could be of practical use for potentializing rAAV-mediated delivery of therapeutic genes.
Cyclohexylideneacetyl Isothiocyanate. Precursor for the Synthesis of 1,3-Thiazaspirocycloalkanes and 1,3-Diazaspirocycloalkanes
Authors: Török Marcel , Dzurilla Milan , Kutschy Peter , Imrich Ján , Danihel Ivan , Rademacher Paul , Bandmann Heinz
Published: July 2002

The N-(4-substituted phenyl)-N'-cyclohexylideneacetylthioureas IIa - IIf were readily prepared by the reaction of cyclohexylideneacetyl isothiocyanate I with 4-substituted anilines. They were cyclized to the 2-(4-substituted phenylimino)-4-oxo-1,3-thiazaspiro[5.5]undecanes IIIa - IIIe in the presence of boron trifluoride etherate and to the 1-(4-substituted phenyl)-4-oxo-2-thioxo-1,3-diazaspiro[5.5]undecanes IVa, IVc - IVf in alkaline medium.
Structure and Electronic Effects of Cobalt Ferrites, CoxFe3-xO4, on Catalytic Decomposition of Isopropyl Alcohol
Authors: Abd El-Salaam Khalf-Alla M. , Said Abd El-Aziz A. , El-Awad Ahmed M. , Hassan Ehsan A. , Abd El-Wahab Mohamed M. M.
Published: July 2002

The cobalt ferrite spinel oxides CoxFe3-xO4 (O < x < 3) have been prepared by coprecipitation. Their structures were characterized by DTA, X-ray diffraction and IR spectra, and their surface properties were determined from nitrogen adsorption isotherms at -196 °C. Conductance of all the compositions was studied with and without isopropanol. The variation of Eσ values was discussed in terms of oxide semiconducting properties and of ion distribution in the octahedral-tetrahedral sites of the spinel structures. The catalytic decomposition of isopropanol at 325 °C in a flow system allowed to conclude that the inverse spinels formed in the iron-rich region are active and selective sites for acetone formation, in contrast to the inverse spinels formed in the cobalt-rich region. On the other hand, the region of normal spinels showed low activity and selectivity to acetone formation. Correlations between the composition and electronic and catalytic properties of the catalysts are reported.
Crystal Structures of α- and β-Allocryptopine
Authors: Marek Jaromír , Dostál Jiří , Slavík Jiří
Published: July 2002

Crystals of α- and β-allocryptopine were studied by X-ray diffraction analysis and have been found to be crystal modifications of allocryptopine. They are both monoclinic with a = 18.401(4) Å, b = 7.1590(10) Å, c = 14.084(3) Å, β = 108.98(3)°, P21/c, Z = 4, V = 1754.5(6) Å3 for α-allocryptopine and a = 11.407(2) Å, b = 11.5890(10) Å, c = 14.6673(3) Å, β = 107.82(2)°, P21/n, Z = 4, V = 1845.9(5) Å3 for β-allocryptopine. No major differences in the conformations were found, slight differences are only in the positions of dioxolane rings.
Provocation by eucapnic voluntary hyperpnoea to identify exercise induced bronchoconstriction
Authors: Anderson S D , Argyros G J , Magnussen H , Holzer K
Published: July 2002

The International Olympic Committee Medical Commission (IOC-MC) requires notification for use of a β2agonist at the Winter Olympic Games in Salt Lake City. This notification will be required seven days before the event and must be accompanied by objective evidence that justifies the need to use one. The IOC-MC has expressed the viewpoint that, at present, eucapnic voluntary hyperpnoea (EVH) is the optimal laboratory challenge to confirm that an athlete has exercise induced bronchoconstriction (EIB). The EVH test recommended was specifically designed to identify EIB. EVH has been performed in thousands of subjects in both the laboratory and the field. The test requires the subject to hyperventilate dry air containing 5% carbon dioxide at room temperature for six minutes at a target ventilation of 30 times the subject's forced expiratory volume in one second (FEV1). The test conditions can be modified to simulate the conditions that give the athlete their symptoms with exercise. A reduction in FEV1of 10% or more of the value before the test is considered positive.
Mass casualties and triage at a sporting event
Authors: Delaney J S , Drummond R
Published: July 2002

When a sports medicine doctor provides coverage for a sporting event with a large number of athletes and spectators, he or she should always be aware that the potential for a large number of injuries exists. In the event of a mass casualty incident that overwhelms the available medical resources, he or she may be the most qualified professional present to triage and organise patient care. Certain basic rules of triage in a disaster situation should be followed, the goal being to save as many lives as possible. Special circumstances, such as crush injuries, lightning strikes, and blast injuries, may affect the triage and initial care of injured patients.
Floral development and anatomy ofPentadiplandra(Pentadiplandraceae): a key genus in the identification of floral morphological trends in the core Brassicales
Authors: Ronse De Craene Louis P
Published: July 2002

The development and anatomy of leaves and flowers have been investigated in the monotypic species Pentadiplandra brazzeana to discuss its position relative to the core Brassicales and to clarify floral evolutionary trends within the order. Young leaves are flanked by two large stipules that shrivel at anthesis. Young flowers develop as elliptical primordia on a flattened raceme. Sepal initiation is sequential, starting with the lateral sepals and ending with three median sepals. The petals and diplostemonous androecium arise as regular whorls. Five antesepalous carpels develop into a saccate gynoecium with axile placentation. Petals develop a cushion-like basal appendage covering the extrastaminal nectary. Several ontogenetic and anatomical data of the flower support the basal position of Pentadiplandra in the evolution of the core Brassicales and for the derivation of the order from pentamerous diplostemonous ancestors. A derivation of the tetramerous Capparaceae and Brassicaceae as well as hexamerous Tovariaceae is discussed. A number of synapomorphies are identified: sequential sepal initiation with laterals preceding median sepals, retarded petal growth, a (andro)gynophore, the extrastaminal nectary, and stipulate leaves. The peculiar androecium of the Brassicaceae is caused by the strong median compression of the flower, leading to the loss and displacement of median stamens. The derivation of a parietal placenta from an axile placenta is supported. Evidence supports a close link with either Tovariaceae or Capparaceae, concomitant with macromolecular results.Key words: core Brassicales, Capparaceae, Pentadiplandra brazzeana, Tovariaceae, molecular phylogeny, floral development, anatomy, diplostemony, placentation.
Experimental investigation of the uplift behaviour of circular plate anchors embedded in sand
Authors: Ilamparuthi K , Dickin E A , Muthukrisnaiah K
Published: July 2002

An experimental investigation of the uplift behaviour of relatively large scale model circular plate anchors up to 400 mm in diameter embedded in loose, medium-dense, and dense dry sand is described. Uplift capacity is strongly influenced by anchor diameter, embedment ratio, and sand density. In tests on shallow half-cut models, a gently curved rupture surface emerged from the top edge of the anchor to the sand surface at approximately ϕ/2 to the vertical, where ϕ is the angle of shearing resistance. For a deep anchor, a balloon-shaped rupture surface emerged at 0.8ϕ to the vertical immediately above the anchor and was confined within the sand bed. The load-displacement behaviour of full-shaped models was three-phase and two-phase for shallow and deep anchors, respectively. Alternative methods of determining the critical embedment ratio are considered, and values of 4.8, 5.9, and 6.8 are proposed for loose, medium-dense, and dense sand, respectively. Empirical equations are presented which yield breakout factors similar to those from many published laboratory and field studies.Key words: circular anchor, uplift capacity, sand, critical embedment ratio, failure mechanism.
Kinetic characterization and inhibition of the rat MAB elastase-2, an angiotensin I-converting serine protease
Authors: Santos Carlos F , Paula Carmem A , Salgado Maria Cristina O. , Oliveira Eduardo Brandt
Published: July 2002

An elastase-2 has been recently described as the major angiotensin (Ang) II-forming enzyme of the rat mesenteric arterial bed (MAB) perfusate. Here, we have investigated the interaction of affinity-purified rat MAB elastase-2 with some substrates and inhibitors of both pancreatic elastases-2 and Ang II-forming chymases. The Ang II precursor [Pro11-D-Ala12]-Ang I was converted into Ang II by the rat MAB elastase-2 with a catalytic efficiency of 8.6 min1·µM1, and the chromogenic substrates N-succinyl-Ala-Ala-Pro-Leu-p-nitroanilide and N-succinyl-Ala-Ala-Pro-Phe-p-nitroanilide were hydrolyzed by the enzyme with catalytic efficiencies of 10.6 min1·µM1and 7.6 min1·µM1, respectively. The non-cleavable peptide inhibitor CH-5450 inhibited the rat MAB elastase-2 activities toward the substrates Ang I (IC50= 49 µM) and N-succinyl-Ala-Ala-Pro-Phe-p-nitroanilide (IC50= 4.8 µM), whereas N-acetyl-Ala-Ala-Pro-Leu-chloromethylketone, an effective active site-directed inhibitor of pancreatic elastase-2, efficiently blocked the Ang II-generating activity of the rat MAB enzyme (IC50= 4.5 µM). Altogether, the data presented here confirm and extend the enzymological similarities between pancreatic elastase-2 and its rat MAB counterpart. Moreover, the thus far unrealized interaction of elastase-2 with [Pro11-D-Ala12]-Ang I and CH-5450, both regarded as selective for chymases, suggests that evidence for the in vivo formation of Ang II by chymases may have been overestimated in previous investigations of Ang II-forming pathways.Key words: angiotensin, elastase-2, chymase, [Pro11-D-Ala12]-Ang I, CH-5450.
TWO-DIMENSIONAL CELLULAR AUTOMATA WITH MEMORY: PATTERNS STARTING WITH A SINGLE SITE SEED
Authors: ALONSO-SANZ RAMÓN , MARTÍN MARGARITA
Published: July 2002

Standard Cellular Automata (CA) are ahistoric (memoryless), i.e., the new state of a cell depends on its neighborhood configuration only at the preceding time step. The effect of keeping ahistoric memory of all past iterations in two-dimensional CA, featuring each cell by its most frequent state is analyzed in this work.
A TOPOLOGICAL INVARIANT OF RG FLOWS IN 2D INTEGRABLE QUANTUM FIELD THEORIES
Authors: CARACCIOLO R. , GLIOZZI F. , TATEO R.
Published: July 2002

We construct a topological invariant of the renormalization group trajectories of a large class of 2D quantum integrable models, described by the thermodynamic Bethe ansatz approach. A geometrical description of this invariant in terms of triangulations of three-dimensional manifolds is proposed and associated dilogarithm identities are proven.
DISCOUNTING IN THE HISTORIC PRISONER'S DILEMMA
Authors: ALONSO-SANZ RAMÓN , MARTÍN M. CARMEN , MARTÍN MARGARITA
Published: July 2002

The standard spatial formulation of the Prisoner's Dilemma (PD) is ahistoric (memoryless): only results generated in the last round are taken into account to decide the next choice. In the standard historic model, all results coming from previous rounds are considered without discounting. The effect of geometric discounting in the historic spatial formulation of PD is assessed in this work. The fate of a single isolated defector surrounded by cooperators and that of some groups of cooperators surrounded by defectors are studied, varying both the discount factor (α) and the temptation (b, the parameter which characterizes the PD game). The effect of noise and stochastic rules are also assessed in the first scenario. The most important finding is that there are some range of parameter values (b, α) for which the evolution dynamics becomes unexpected.
HISTORIC LIFE
Authors: ALONSO-SANZ RAMÓN , MARTÍN M. CARMEN , MARTÍN MARGARITA
Published: July 2002

A variation of Conway's Game of Life (LIFE) is presented in this paper. The rules of LIFE remain unaltered in the variation we name VIDA, but, unlike in LIFE, in VIDA a cell is featured by its most frequent state, not necessarily the last one. As an overall conclusion, it is claimed that the consideration of historic memory of past states has an inertial (or conservating) effect. Thus, small cluster of live cells will not behave so vividly in VIDA as in LIFE could, but greater clusters tend to present higher persistence.
AN EXPERIMENTAL APPLICATION OF THE ANTICONTROL OF HOPF BIFURCATIONS
Authors: ALONSO DIEGO M. , PAOLINI EDUARDO E. , MOIOLA JORGE L.
Published: July 2002

The control of nonlinear systems exhibiting bifurcation phenomena has been the subject of active research in recent years. Contrary to regulation or tracking objectives common in classic control, in some applications it is desirable to achieve an oscillatory behavior. Towards this end, bifurcation control aims at designing a controller to modify the bifurcative dynamical behavior of a complex nonlinear system. Among the available methods, the so-called "anti-control" of Hopf bifurcations is one approach to design limit cycles in a system via feedback control. In this paper, this technique is applied to obtain oscillations of prescribed amplitude in a simple mechanical system: an underactuated pendulum. Two different nonlinear control laws are described and analyzed. Both are designed to modify the coefficients of the linearization matrix of the system via feedback. The first law modifies those coefficients that correspond to the physical parameters, whereas the second one changes some null coefficients of the linearization matrix. The latter results in a simpler controller that requires the measurement of only one state of the system. The dependence of the amplitudes as function of the feedback gains is obtained analytically by means of local approximations, and over a larger range by numerical continuation of the periodic solutions. Theoretical results are contrasted by both computer simulations and experimental results.
SPATIAL FORECASTING: DETECTING DETERMINISM FROM SINGLE SNAPSHOTS
Authors: MARCOS-NIKOLAUS PATRICK , MARTIN-GONZÁLEZ J. M. , SOLÉ RICARD V.
Published: July 2002

In ecological systems, long, high-quality time series of population abundances is seldom available. However, in some cases populations are scattered over spatial domains where physical conditions appear to be homogeneous, and spatial snapshots of population abundance can be obtained. Since these spatial patterns are generated from underlying dynamical rules, an important problem is to detect the presence of determinism in these structures. In this paper, a simple model of determinism detection from spatial snapshots is presented, using a coupled map lattice formalism. It involves a simple forecasting approach where subparts of the lattice are used in order to make predictions based on the distance between neighbors. It is shown that the method is able to properly detect the presence of low-dimensional dynamics from single snapshots.
ON THE CONSTRUCTION OF THE FREE FIELD
Authors: COHN P. M. , REUTENAUER C.
Published: July 2002

We give a linear algebraic construction of the free field, by constructing the category of "representations": an element of the free field is characterized by the class of objects which can be connected by a chain of morphisms and inverse morphisms; we characterize minimal representations of a given element. We characterize power series and polynomials by their representations among all elements of the free field, and give a primary decomposition of the elements of the free field, extending the classical one for rational functions and that of Fliess for noncommutative rational series. We show that each rational identity in the free field may be "trivialized", that is, is a consequence of the axioms of a field. We give an algorithm for the word problem in the free field, using Gröbner bases, different from a previous algorithm of the first author.
QUANTUM EFFECTS IN A ROTATING SPACETIME
Authors: RADU EUGEN , ASTEFANESEI DUMITRU
Published: July 2002

The behavior of a arbitrary coupled quantum scalar field is studied in the background of the Gödel spacetime. Closed forms are derived for the effective action and the vacuum expectation value of quadratic field fluctuations by using ζ-function regularization. Based on these results, we argue that causality violation presented in this spacetime cannot be removed by quantum effects.
SURFACE AND INTERFACE STRAINS REVEALED BY X-RAY DIFFRACTION
Authors: AKIMOTO KOICHI , EMOTO TAKASHI , ISHIKAWA YUYA , ICHIMIYA AYAHIKO
Published: July 2002

We measured strain fields near semiconductor surface by X-ray diffraction. The diffraction geometry was using the extremely asymmetric Bragg-case bulk reflection of a small incident angle to the surface and a large angle exiting from the surface. The incident angle of the X-rays was set near critical angle of total reflection by tuning X-ray energy of synchrotron radiation.

The X-ray intensity of the silicon substrate 311 reflection was measured to study a Si(111) surface in the ultrahigh vacuum chamber. A clean Si (111)-(7 × 7) surface was found to give a sharper X-ray diffraction peak than that of the native oxide/Si(111) system. By comparison of experimental results and theoretical calculations, it was concluded that the thin silicon oxide film itself gives strong strain fields to the silicon substrates of lattice expansion toward the [311] direction.

The strain fields at the Al- and Ag- induced [Formula: see text] surface reconstruction on the Si(111) substrate were also measured. By comparison of experimental results and theoretical calculations, Al-induced reconstruction was suggested to give a strain field to the silicon substrate of lattice expansion toward the [311] direction, whereas Ag-induced reconstruction was suggested to give a strain field to the silicon substrate of lattice compression toward the [311] direction.
Algorithm 688: EPDCOL
Authors: Keast P. , Muir P. H.
Published: July 2002

The software package PDECOL [7] is a popular code among scientists wishing to solve systems of nonlinear partial differential equations. The code is based on a method-of-lines approach, with collocation in the space variable to reduce the problem to a system of ordinary differential equations. There are three principal components: the basis functions employed in the collocation; the method used to solve the system of ordinary differential equations; and the linear equation solver which handles the linear algebra. This paper will concentrate on the third component, and will report on the improvement in the performance of PDECOL resulting from replacing the current linear algebra modules of the code by modules which take full advantage of the special structure of the equations which arise. Savings of over 50 percent in total execution time can be realized.
Resolving the query inference problem using Steiner trees
Authors: Wald Joseph A. , Sorenson Paul G.
Published: July 2002

The query inference problem is to translate a sentence of a query language into an unambiguous representation of a query. A query is represented as an expression over a set of query trees. A metric is introduced for measuring the complexity of a query and also a proposal that a sentence be translated into the least complex query which “satisfies” the sentence. This method of query inference can be used to resolve ambiguous sentences and leads to easier formulation of sentences.
Coloring register pairs
Authors: Briggs Preston , Cooper Keith D. , Torczon Linda
Published: July 2002

Many architectures require that a program use pairs of adjacent registers to hold double-precision floating-point values. Register allocators based on Chaitin's graph-coloring technique have trouble with programs that contain both single-register values and values that require adjacent pairs of registers. In particular, Chaitin's algorithm often produces excessive spilling on such programs. This results in underuse of the register set; the extra loads and stores inserted into the program for spilling also slow execution.

An allocator based on an
optimistic
coloring scheme naturally avoids this problem. Such allocators delay the decision to spill a value until late in the allocation process. This eliminates the over-spilling provoked by adjacent register pairs in Chaitin's scheme.

This paper discusses the representation of register pairs in a graph coloring allocator. It explains the problems that arise with Chaitin's allocator and shows how the optimistic allocator avoids them. It provides a rationale for determining how to add larger aggregates to the interference graph.