bluuebunny/crossref_metadata_2025_split huggingface dataset:
The multiplicity of a set of homogeneous polynomials over a
commutative ring
Authors: KIRBY DAVID , REES DAVID 
Published: July 2002

Some thirty years ago Buchsbaum and Rim [1]

extended the notion of multiplicity
e(a1, …, an;
E)
for elements a1, …, an

of a commutative ring R with identity and a
Noetherian R-module E (≠0) with
lengthR
(E/[sum ]nt=1aiE) finite to give a multiplicity

e((aij); E)
associated with E and an m×n matrix
(aij) over R satisfying a certain

extended finiteness condition. One of their results states that for each
of a set of m
complexes depending on E, (aij) the

Euler–Poincaré characteristic is a certain integer
multiple of e((aij); E),
at least
when R is a local ring.Some of these ideas were taken up in [4] where it
is
shown that when n[ges ]m−1,
each of the complexes K((aij); E;
t)
with t∈ℤ introduced in [3] also have

e((aij); E) as
their Euler–Poincaré characteristic. With a slight change
in
viewpoint (aij) can be replaced by linear
forms
aj=[sum ]mi=1aijxi
(j=1, …, n) of the graded polynomial ring
R[x1, …, xm];

the complex K((aij); E;
t)
then becomes the component of degree t in a certain graded double
complexformula herewhere K(a1, …, an;

F) is the standard Koszul complex (see [4; section
2]). From this
point of view the construction can be extended to allow the homogeneous
polynomials
a1, …, an
to have any (possibly unequal) positive degrees [6].
The main aim of the
present note is to extend similarly the results of [4]
and
to strengthen those results
to give information on the vanishing of the multiplicity.
Legal Issues including Liability associated with the Acquisition, Use, and Failure of GPS/GNSS
Authors: Michael Gregory E. 
Published: July 2002

This, and the following two papers, were presented during the European GNSS98 Symposium
held at the Centre de Congrès Pierre Baudis, Toulouse, France, from 20–23 October 1998.It is now clear that Global Positioning Systems (GPS) will be the primary navigational and positioning tool used as we move into the 21st century. As a result of the continued expansion and development of GPS, concerns have been voiced about the liability associated with development, construction, and use of the system. No short paper can explore all of the various liability issues associated with GPS. However, this paper will touch upon various liability issues in the hope that this analysis will continue with the development of GPS.
The crisis in global fisheries: can trade laws provide a cure?
Authors: STONE CHRISTOPHER D. 
Published: July 2002

Fisheries, over-capacity and subsidiesA consensus is emerging regarding world fisheries.Overall, the world's living marine resources are being overexploited; in many major areas a reprieve in the level of fishing would assure larger and more valuable fish supplies in the long term. Less would be more.The system is uneconomical and unsustainable. We are paying an unnecessarily high price, in capture costs and environmental degradation, for a dwindling catch.Conventional management measures (including time, space and gear constraints) have not proved themselves capable of stanching excessive fishing effort. Indeed, many of the traditional measures, by prohibiting the most economical means of fishing, amplify inefficiencies, raising unit costs without compensatory benefits in catch reduction.Increasing blame is being placed on over-capacity. As long as investment in harvest capacity is excessive, in other words beyond the level required for efficient attainment of fisheries objectives, effective regulatory efforts are frustrated at the levels of both rule making and enforcement.
String rewriting and homology of monoids
Authors: COHEN DANIEL E. 
Published: July 2002

Results of Anick (1986), Squier (1987), Kobayashi (1990), Brown
(1992b),
and others, show
that a monoid with a finite convergent rewriting system satisfies a homological
condition known as FP∞.In this paper we give a simplified version of Brown's proof, which
is
conceptual, in
contrast with the other proofs, which are computational.We also collect together a large number of results and examples of
monoids and groups
that satisfy FP∞ and others that do not. These
may provide techniques for showing that
various monoids do not have finite convergent rewriting systems, as well
as explicit
examples with which methods can be tested.
A Gene Encoding a Hevein-Like Protein from Elderberry Fruits Is Homologous to PR-4 and Class V Chitinase Genes1
Authors: Van Damme Els J.M. , Charels Diana , Roy Soma , Tierens Koenraad , Barre Annick , Martins José C. , Rougé Pierre , Van Leuven Fred , Does Mirjam , Peumans Willy J. 
Published: July 2002

Abstract
We isolated SN-HLPf (Sambucusnigrahevein-like fruitprotein), a hevein-like chitin-binding protein, from mature elderberry fruits. Cloning of the corresponding gene demonstrated that SN-HLPf is synthesized as a chimeric precursor consisting of an N-terminal chitin-binding domain corresponding to the mature elderberry protein and an unrelated C-terminal domain. Sequence comparisons indicated that the N-terminal domain of this precursor has high sequence similarity with the N-terminal domain of class I PR-4 (pathogenesis-related) proteins, whereas the C terminus is most closely related to that of class V chitinases. On the basis of these sequence homologies the gene encoding SN-HLPf can be considered a hybrid between a PR-4 and a class V chitinase gene.
Heritable Variation in Quinone-Induced Haustorium Development in the Parasitic Plant Triphysaria
Authors: Jamison Denneal S. , Yoder John I. 
Published: July 2002

Abstract
We are using the facultative hemiparasite,Triphysaria, as a model for studying host-parasite signaling in the Scrophulariaceae. Parasitic members of this family form subterranean connections, or haustoria, on neighboring host roots to access host water and nutrients. These parasitic organs develop in response to haustorial-inducing factors contained in host root exudates. A well-characterized inducing factor, 2, 6-dimethoxy-p-benzoquinone (DMBQ), can be used to trigger in vitro haustorium formation in the roots ofTriphysaria. We have assayed three species,Triphysaria eriantha (Benth.) Chuang and Heckard, Triphysaria pusilla (Benth.) Chuang and Heckard, andTriphysaria versicolor Fischer and C. Meyer, for haustorium development in response to DMBQ. There were significant differences between the species in their ability to recognize and respond to this quinone. Ninety percent of T. versicolorindividuals responded, whereas only 40% of T. pusillaand less than 10% of T. eriantha formed haustoria. Within field collections of self-pollinating T. pusilla, differential responsiveness to DMBQ was seen in distinct maternal families. Assaying haustorium development in subsequent generations of self-pollinated T. pusilla showed that DMBQ responsiveness was heritable. Reciprocal crosses between T. eriantha and T. versicolor demonstrated that DMBQ responsiveness was influenced by maternal factors. These results demonstrate heritable, natural variation in the recognition of a haustorial-inducing factor by a parasitic member of the Scrophulariaceae.
Structures of [Pd(NH3)2
X
2] and its chemical transformation in the solid state
Authors: Kirik S. D. , Solovyov L. A. , Blokhin A. I. , Yakimov I. S. 
Published: July 2002

Crystal structures of [Pd(NH3)2
X
2] complexes, where X = Br or I, diamminediiodo-/-dibromopalladium(II), have been studied by X-ray powder diffraction. The series consists of five complexes: cis-[Pd(NH3)2Br2] (I) [a = 13.3202 (7), b = 12.7223 (6), c = 7.05854 (3) Å, Z = 8, space group Pbca], trans-[Pd(NH3)2Br2] (II) [a = 6.7854 (3), b = 7.1057 (3), c = 6.6241 (2) Å, α = 103.221 (3), β = 102.514 (2), γ = 100.386 (3)°, Z = 2, space group P\overline 1], β-trans-[Pd(NH3)2Br2] (III) [a = 8.4315 (3), b = 8.4206 (3), c = 8.0916 (2) Å, Z = 4, space group Pbca], cis-[Pd(NH3)2I2] (IV) [a = 13.9060 (8), b = 13.5035 (8), c = 7.5050 (4) Å, Z = 8, space group Pbca], and β-trans-[Pd(NH3)2I2] (V) [a = 8.8347 (5), b = 8.8410 (5), c = 8.6081 (2) Å, Z = 4, space group Pbca]. Patterson synthesis and Rietveld refinement have been used for structural determination. Molecular structures with column- or parquet-type packing of flat complexes are characteristic of these substances. Corresponding cis- and β-trans compounds are isostructural. The thermal transformations cis→trans→β-trans (cis→β-trans in the case of iodine) are considered. Cl derivatives are also discussed. The transformations proceed irreversibly and are accompanied by decreasing specific volume. Owing to these features, they can be classified as chemical reactions. High-temperature X-ray powder diffraction was used to study the transformations in air. The set of data is consistent with a solid state transformation from cis to trans. According to this model, the columns of molecules remain intact during the process, and the transformation proceeds via the breaking of Pd...X and Pd...N intermolecular bonds. The powder diffraction data have been deposited in ICDD-JCPDS (45-0596, 46-0876, 46-0879, 47-1690, 48-1185).
Structure of ν-Al80.61Cr10.71Fe8.68, a giant hexagonal approximant of a quasicrystal determined by a combination of electron microscopy and X-ray diffraction
Authors: Mo Z. M. , Zhou H. Y. , Kuo K. H. 
Published: July 2002

ν-Al80.61Cr10.71Fe8.68, P63/m (No. 176), a = 40.68 (7), c = 12.546 (1) Å, V = 17 983 (8) Å3, atoms/cell = 1184.56, D

x
= 3.518 g cm−3, λ(Mo Kα) = 0.71069 Å, μ = 5.032 mm−1, F(000) = 18 433, T = 293 K, final R = 0.075 for 3854 reflections with F

o
> 4σ(F

o
). The [001] high-resolution electron-microscopic image of the ν-AlCrFe phase clearly shows similar local characteristics to those given by the complex icosahedral cluster found in somewhat smaller hexagonal approximant structures, such as κ-Al76Cr18Ni6 [a = 17.674 (3), c = 12.516 (3) Å; Sato et al. (1997). Acta Cryst. C53, 1531–1533; Marsh (1998). Acta Cryst. B54, 925–926] and λ-Al4.32Mn [a = 28.382 (9), c = 12.389 (2) Å; Kreiner & Franzen (1997). J. Alloys Compd.
261, 83–104]. Using the known atomic distribution of this icosahedral cluster in the κ and λ phases as the starting point, the structure of the ν phase, a hexagonal intermetallic compound with probably the largest a parameter, was solved by X-ray single-crystal diffraction using direct methods. As in κ and λ phases, almost all TM (transition metal) atoms in the complex icosahedral cluster are icosahedrally coordinated. However, contrary to the λ structure in which about 98% of the TM atoms have icosahedral coordination, the TM atoms in the ν structure also form capped pentagonal prisms in the region between these complex icosahedral clusters, yielding an average icosahedral coordination of about 70% for TM atoms. After rapid solidification, the ν phase occurs together with a decagonal quasicrystal with a periodicity of about 12.5 Å along its tenfold axis and thus also consists of six layers, two flat ones each sandwiched between two puckered layers in mirror reflection, stacked along the c axis.
Initiating a crystallographic study of UDP-galactopyranose mutase from Escherichia coli
Authors: McMahon Stephen A. , Leonard Gordon A. , Buchanan Louise V. , Giraud Marie-France , Naismith James H. 
Published: July 2002

UDP-galactopyranose mutase, the enzyme responsible for the conversion of UDP-galactopyranose to UDP-galactofuranose, has been crystallized in a form suitable for X-ray diffraction studies. UDP-galactofuranose is a key component of mycobacterial cell walls. Crystals of both the native protein and a selenomethionine variant have been grown by the vapour-diffusion method in hanging drops, and diffract to beyond 3.0 Å using synchrotron radiation. Equilibration was against a solution of 20%(w/v) polyethylene glycol (4K), 12%(v/v) 2-propanol, 0.1 M HEPES pH 7.6 at 293.5 K. Crystals grow as thin plates of dimensions 0.4 × 0.2 × ∼0.02 mm. They are orthorhombic, space group P21, with unit-cell dimensions a = 71.12, b = 58.42, c = 96.38 Å, β = 96.38°. 92% (native) and 94% (selenomethionine) complete data sets have been recorded to 2.9 Å (R
merge = 5.0%) and 3.0 Å (R
merge = 6.9%), respectively. The Matthews coefficient is 2.35 Å3 Da−1 for a dimer in the asymmetric unit, the solvent content being 47%. Diffraction data have also been recorded on a putative platinum derivative to 3.5 Å.
The structure of mouse tumour-necrosis factor at 1.4 Å resolution: towards modulation of its selectivity and trimerization
Authors: Baeyens K. J. , De Bondt H. L. , Raeymaekers A. , Fiers W. , De Ranter C. J. 
Published: July 2002

The 1.4 Å resolution structure of recombinant mouse tumour-necrosis factor α (mTNF) at 100 K has been determined. The crystals are triclinic, space group P1, with unit-cell parameters a = 48.06, b = 48.18, c = 51.01 Å, α = 114.8, β = 103.6, γ = 91.1°. The structure was refined to a final crystallographic R value of 19.7% (R
free = 23.3%), including 3477 protein atoms, one 2-propanol molecule, one Tris molecule and 240 water molecules. Throughout the crystal lattice, the trimers are differently packed compared with human TNF, which was crystallized in the tetragonal space group P41212 and refined to 2.6 Å resolution. The structures of mTNF and human TNF are very similar, diverging mainly in regions that are either flexible and/or involved in crystal packing. Some loops in mTNF which contain residues important for receptor binding are better resolved than in human TNF, such as the surface-exposed loops 30–34 and 144–147, which are also important for receptor specificity. Compared with human TNFs, the channel formed by the three monomers in mTNF is narrower. One 2-propanol molecule trapped in the trimeric channel could be a lead compound for the design of TNF inhibitors.
Crystallization and preliminary diffraction data of a platelet-aggregation inhibitor from the venom of Agkistrodon piscivorus piscivorus (North American water moccasin)
Authors: Arni R. K. , Padmanabhan K.P. , Tulinsky A. 
Published: July 2002

Applaggin (Agkistrodon piscivorus piscivorus platelet-aggregation inhibitor) is a potent inhibitor of blood platelet aggregation derived from the venom of the North American water moccasin. The protein consists of 71 amino acids, is rich in cysteines, contains the sequence-recognition site of adhesion proteins at positions 50–52 (Arg-Gly-Asp) and shares high sequence homology with other snake-venom disintegrins such as echistatin, kistrin and trigramin. Single crystals of applaggin have been grown and X-ray diffraction data have been collected to a resolution of 3.2 Å. The crystals belong to space group P41212 (or its enantiomorph), with unit-cell dimensions a = b = 63.35, c = 74.18 Å and two molecules per asymmetric unit. Molecular replacement using models constructed from the NMR structures of echistatin and kistrin has not been successful in producing a trial structure for applaggin.
Crystallization and preliminary X-ray analysis of birch-pollen allergen Bet v 1 in complex with a murine monoclonal IgG Fab′ fragment
Authors: Spangfort Michael D. , Mirza Osman , Svensson L. Anders , Larsen Jørgen N. , Gajhede Michael , Ipsen Henrik 
Published: July 2002

The human type I allergic response is characterized by the presence of allergen-specific serum immunoglobulin E (IgE). Allergen-mediated cross-linking of receptor-bound IgE on the surface of mast cells and circulating basophils triggers the release of mediators, resulting in the development of the clinical symptoms of allergy. In order to study the structural basis of allergen–antibody interaction, a complex between the major birch-pollen allergen Bet v 1 and a Fab′ fragment isolated from the murine monoclonal Bet v 1 antibody BV16 has been crystallized. Complex crystals belong to space group P1, with unit-cell parameters a = 91.65, b = 99.14, c = 108.90 Å, α = 105.7, β = 98.32, γ = 97.62°, and diffract to 2.9 Å resolution when analyzed at 100 K using synchrotron-generated X-rays.
Crystallization and preliminary crystal analysis of yeast hexokinase PI and PII
Authors: Kuser Paula R. , Golubev Alexander M. , Polikarpov Igor 
Published: July 2002

Hexokinase is the prime enzyme of the Embden–Meyerhof pathway and is responsible for the first stage of energy conversion. It catalyzes the transfer of a phosphate to glucose to form glucose-6-phosphate. Yeast hexokinase PII is also known to play an important role in glucose signal transduction. Crystals of yeast hexokinase isoforms PI and PII were obtained by vapour-diffusion techniques using the hanging-drop method. Isoform PI crystals belong to the space group P212121, with unit-cell parameters a = 62.12, b = 78.87, c = 144.74 Å. Unit-cell parameters for isoform PII crystals are a = b = 142.81, c = 58.46 Å and the space group is I4. Synchrotron diffraction data have been collected to 2.2 Å resolution from the isoform PII crystal, whereas isoform PI diffracted to 3.1 Å.
Crystallization and preliminary crystallographic studies of ribosome recycling factor from Escherichia coli
Authors: Yun Jungmin , Kim Wookhyun , Ha Sung Chul , Eom Soo-Hyun , Suh Se Won , Kim Kyeong Kyu 
Published: July 2002

Ribosome recycling factor (RRF) catalyzes the disassembly of a termination complex during the final stage of protein synthesis. RRF from Escherichia coli has been crystallized with PEG 400 as precipitant at 287 K. The crystal belongs to the trigonal space group P3121 (or P3221), with unit-cell parameters a = b = 48.08, c = 141.67 Å. Native data were collected from a frozen crystal to a resolution of 3.0 Å on a Cu Kα rotating-anode X-ray source.
Timing and structural consideration for the processing of mitochondrial matrix space proteins by the mitochondrial processing peptidase (MPP)
Authors: Mukhopadhyay Abhijit , Hammen Philip , Waltner‐Law Mary , Weiner Henry 
Published: July 2002

AbstractMost mitochondrial matrix space proteins are synthesized as a precursor protein, and the N‐terminal extension of amino acids that served as the leader sequence is removed after import by the action of a metalloprotease called mitochondrial processing peptidase (MPP). The crystal structure of MPP has been solved very recently, and it has been shown that synthetic leader peptides bind with MPP in an extended conformation. However, it is not known how MPP recognizes hundreds of leader peptides with different primary and secondary structures or when during import the leader is removed. Here we took advantage of the fact that the structure of the leader from rat liver aldehyde dehydrogenase has been determined by 2D‐NMR to possess two helical portions separated by a three amino acid (RGP) linker. When the linker was deleted, the leader formed one long continuous helix that can target a protein to the matrix space but is not removed by the action of MPP. Repeats of two and three leaders were fused to the precursor protein to determine the stage of import at which processing occurs, if MPP could function as an endo peptidase, and if it would process if the cleavage site was part of a helix. Native or linker deleted constructs were used. Import into isolated yeast mitochondria or processing with recombinantly expressed MPP was performed. It was concluded that processing did not occur as the precursor was just entering the matrix space, but most likely coincided with the folding of the protein. Further, finding that hydrolysis could not take place if the processing site was part of a stable helix is consistent with the crystal structure of MPP. Lastly, it was found that MPP could function at sites as far as 108 residues from the N terminus of the precursor protein, but its ability to process decreases exponentially as the distance increases.
Control of the allosteric equilibrium of hemoglobin by cross‐linking agents
Authors: Marden Michael C. , Cabanes‐Macheteau Marion , Babes Alexandru , Kiger Laurent , Griffon Nathalie , Poyart Claude , Boyiri Telih , Safo Martin K. , Abraham Donald J. 
Published: July 2002

AbstractThe kinetics of ligand rebinding have been studied for modified or cross‐linked hemoglobins (Hbs). Several compounds were tested that interact with α Val 1 or involve a cross‐link between α Val 1 and α Lys 99 of the opposite dimer. By varying the length of certain cross‐linking molecules, a wide range in the allosteric equilibrium could be obtained. Several of the mono‐aldehyde modified Hbs show a shift toward the high affinity conformation of Hb. At the other extreme, for certain di‐aldehyde cross‐linked Hbs, the CO kinetics are typical of binding to deoxy Hb, even at low photodissociation levels, with which the dominant photoproduct is the triply liganded species; in these cases the hemoglobin does not switch from the low to high affinity state until after the fourth ligand is bound. Although each modified Hb shows only two distinct rates, the kinetic data as a function of dissociation level cannot be simulated with a simple two‐state model. A critical length is observed for the maximum shift toward the low affinity T‐state. Longer or shorter lengths of the cross‐linker yielded more high affinity R‐state. Unlike native Hb, which is in equilibrium with free dimers, the cross‐linked Hbs maintain the fraction slow kinetics, which is unique to Hb tetramers, even at 0.5 μM (total heme). Addition of HbCN to unmodified HbCO solutions results in dimer exchange, which decreases the relative fraction of slow bimolecular kinetics; the cross‐linked Hbs did not show such an effect, indicating that they do not participate in dimer exchange.
Cloning, Nucleotide Sequencing, and Analysis of the Gene Encoding an AmpC β-Lactamase in
Acinetobacter baumannii
Authors: Bou Germán , Martínez-Beltrán Jesús 
Published: July 2002

ABSTRACT

A clinical strain of
Acinetobacter baumannii
(strain Ab RYC 52763/97) that was isolated during an outbreak in our hospital and that was resistant to all β-lactam antibiotics tested produced three β-lactamases: a TEM-1-type (pI, 5.4) plasmid-mediated β-lactamase, a chromosomally mediated OXA-derived (pI, 9.0) β-lactamase, and a presumptive chromosomal cephalosporinase (pI, 9.4). The nucleotide sequence of the chromosomal cephalosporinase gene shows for the first time the gene encoding an AmpC β-lactamase in
A. baumannii
. In addition, we report here the biochemical properties of this
A. baumannii
AmpC β-lactamase.
Antipneumococcal Activities of GAR-936 (a New Glycylcycline) Compared to Those of Nine Other Agents against Penicillin-Susceptible and -Resistant Pneumococci
Authors: Hoellman Dianne B. , Pankuch Glenn A. , Jacobs Michael R. , Appelbaum Peter C. 
Published: July 2002

ABSTRACT
GAR-936, a new glycylcycline, had lower MICs (≤0.016 to 0.125 μg/ml) for 201 penicillin- and tetracycline-susceptible and -resistant pneumococcal strains than tetracycline (≤0.06 to 128 μg/ml), minocycline (≤0.06 to 16.0 μg/ml), or doxycycline (≤0.06 to 32.0 μg/ml). GAR-936 was also bactericidal against 11 of 12 strains tested at the MIC after 24 h, with significant kill rates at earlier time points.
Activities of Antimicrobial Agents against Intracellular Pneumococci
Authors: Mandell Gerald L. , Coleman Elizabeth J. 
Published: July 2002

ABSTRACT
Pneumococci can enter and survive inside human lung alveolar carcinoma cells. We examined the activity of azithromycin, gentamicin, levofloxacin, moxifloxacin, penicillin G, rifampin, telithromycin, and trovafloxacin against pneumococci inside and outside cells. We found that moxifloxacin, trovafloxacin, and telithromycin were the most active, but only telithromycin killed all intracellular organisms.