bluuebunny/crossref_metadata_2025_split huggingface dataset:
On the boundary-layer structure of
patterns of convection in
rectangular-planform containers
Authors: DANIELS P. G. , LEE A. T. 
Published: July 2002

This paper considers the structure of steady-state solutions of the Swift–Hohenberg
equation describing convection in shallow rectangular-planform containers heated
from below. The lateral dimensions of the planform are assumed to be much larger
than the characteristic wavelength of convection. Results are restricted to patterns
composed of rolls orthogonal to the sides of the rectangle in which case convection
sets in at a critical value of the Rayleigh number in the form of rolls parallel to
the shorter sides. This primary bifurcation from the conductive state of no motion
produces a solution which subsequently undergoes a secondary bifurcation in which
the low-amplitude motion near the shorter sides is replaced locally by cross-rolls
perpendicular to the sides. This results in the formation of grain boundaries (or
domain boundaries) within the fluid which mark the division between the different
roll orientations.With increasing Rayleigh number the grain boundaries approach the sides of the
rectangle and a boundary-layer structure is formed. In the present paper the method
of matched asymptotic expansions is used to determine this boundary-layer structure
and to predict the location of the grain boundaries. An interesting feature of the
solution is that the grain boundaries develop significant curvature and bend into the
corners of the rectangle, where the local solution is also determined.The results are compared with numerical computations of the secondary solution
branch and with previous numerical and experimental work.
Sampling (hetero)sexuality: diva-ness and discipline in electronic dance music
Authors: Loza Susana 
Published: July 2002

Cyborgs, fembots and posthumans: electronic dance music and the biopolitics of fucking machinesIn the technophilic West, netizens, infomorphs and the audio digerati triumphantly-if-precociously herald this as the dawn of disembodiment. These reality hackers dream in binary code. They yearn to manufacture human-alien hybrids, ethical androids and genetically programmed clones. They already engineer digital soul divas, aural cyborgs, Nintendo's voluptuously overdrawn robo-bimbos, and the supernaturally and surgically perfect bodies purchased at Lasers R' US. They share the meat-hating philosophies of the cyber-protagonists of Neuromancer, Snow Crash and Software. They willingly computerise their passions via text sex, MUD-based gender masquerades, naughty newsgroups, techno-fetishistic video games, virtual reality-based erotic escapades, and pornosonic digital samples. Nonetheless, it seems that for the rest of us to join these intrepid cybernauts in their Age of immaterial Information, our too-solid bodies must first be anaesthetised with utopian visions and sounds of an incorporeal future. So electronic dance music, popular culture and modern science inject the flesh with fantasies of immortality, limitless pleasures, and unadulterated agency. With their tax-funded market research and their potent techno-imaginings, entertainment systems, netters, digital dance music producers, and radically hopeful scientists prepare human matter to be dematerialised and devoured byte by agonising byte. In other words, they passionately fabricate the human-machine hybrid also known as the cyborg, the fembot and the posthuman. These techno-organic entities traverse the space between desire and dread; their indeterminate forms simultaneously destabilise and reconfigure the dualistic limits of liberal humanist subjectivity. Each incarnation plots the feared consequences and perplexing possibilities of boundary transgressions between the human and the machine quite differently.
Beginnings of robotics as a separate discipline of technical sciences
and some fundamental results - a personal view
Authors: Vukobratovic Miomir 
Published: July 2002

Based on the author's knowledge the paper gives a brief account of some of the scientific achievements of robotics that were of crucial importance to its development.In a rough chronological order these are: zero-moment concept and semi-inverse method;
recursive formulation of robot dynamics; computer-aided derivation of robot dynamics in symbolic form; dynamic approach to generation of trajectories of robotic manipulators; centralized feedforward control in robotics; robot dynamic control; decentralized control and observer applied to strongly coupled active mechanisms; force feedback in dynamic control of robots; decentralized control stability tests for robotic mechanisms; underactuated robotic systems; practical stability tests in robotics; unified approach to control laws synthesis for robot interacting with dynamic environment; modeling and control of multi-arm cooperating
robots interacting with environment; connectionist algorithms for advanced learning control
of robots interacting with dynamic environment; fuzzy logic robot control with model-based dynamic compensation, and internal redundancy – a new way to improve robot dynamic performance.
Characterization of Flavonol Synthase and Leucoanthocyanidin Dioxygenase Genes in Arabidopsis (Further Evidence for Differential Regulation of "Early" and "Late" Genes)
Authors: Pelletier M. K. , Murrell J. R. , Shirley B. W. 
Published: July 2002

Abstract
As part of an ongoing investigation into the organization and regulation of the flavonoid biosynthetic pathway, two Arabidopsis thaliana expressed sequence tag (EST) clones (153O10T7 and YAY780) with high homology to leucoanthocyanidin dioxygenase (LDOX) or flavonol synthase (FLS) were identified. EST YAY780 was sequenced and found to encode a protein 49 to 78% identical to all LDOX sequences in the database. EST 153O10T7 was used to isolate a genomic clone encoding a protein with 59 to 61% sequence identity to petunia (Petunia hybrida) and potato (Solanum tuberosum) FLS. DNA blot analysis was used to screen the Arabidopsis genome for sequences related to FLS and LDOX and to determine the positions of the two clones on the RI map. The expression patterns of FLS and LDOX in etiolated seedlings moved to white light and in two putative regulatory mutants (ttg and tt8) were determined by RNA blot analysis. These studies indicate that FLS is an “early” flavonoid gene in Arabidopsis seedlings, whereas LDOX is a “late” gene. Furthermore, FLS is the first flavonoid enzyme identified in Arabidopsis that may be encoded by a gene family.
Cloning, Expression inEscherichia coli, and Characterization ofArabidopsis thalianaUMP/CMP Kinase1
Authors: Zhou Lan , Lacroute François , Thornburg Robert 
Published: July 2002

AbstractA cDNA encoding theArabidopsis thaliana uridine 5′-monophosphate (UMP)/cytidine 5′-monophosphate (CMP) kinase was isolated by complementation of a Saccharomyces cerevisiae ura6 mutant. The deduced amino acid sequence of the plant UMP/CMP kinase has 50% identity with other eukaryotic UMP/CMP kinase proteins. The cDNA was subcloned into pGEX-4T-3 and expressed as a glutathione S-transferase fusion protein in Escherichia coli. Following proteolytic digestion, the plant UMP/CMP kinase was purified and analyzed for its structural and kinetic properties. The mass, N-terminal sequence, and total amino acid composition agreed with the sequence and composition predicted from the cDNA sequence. Kinetic analysis revealed that the UMP/CMP kinase preferentially uses ATP (Michaelis constant [Km] = 29 μm when UMP is the other substrate andKm = 292 μm when CMP is the other substrate) as a phosphate donor. However, both UMP (Km = 153 μm) and CMP (Km = 266 μm) were equally acceptable as the phosphate acceptor. The optimal pH for the enzyme is 6.5. P1, P5-di(adenosine-5′) pentaphosphate was found to be a competitive inhibitor of both ATP and UMP.
Characterization of Two Divergent Endo-β-1,4-Glucanase cDNA Clones Highly Expressed in the Nonclimacteric Strawberry Fruit
Authors: Llop-Tous Immaculada , Domı́nguez-Puigjaner Eva , Palomer Xavier , Vendrell Miquel 
Published: July 2002

Abstract
Two cDNAs clones (Cel1and Cel2) encoding divergent endo-β-1,4-glucanases (EGases) have been isolated from a cDNA library obtained from ripe strawberry (Fragaria xananassa Duch) fruit. The analysis of the amino acid sequence suggests thatCel1 and Cel2 EGases have different secondary and tertiary structures and that they differ in the presence of potential N-glycosylation sites. By in vitro translation we show that Cel1 and Cel2bear a functional signal peptide, the cleavage of which yields mature proteins of 52 and 60 kD, respectively. Phylogenetic analysis revealed that the Cel2 EGase diverged early in evolution from other plant EGases. Northern analysis showed that both EGases are highly expressed in fruit and that they have different temporal patterns of accumulation. The Cel2 EGase was expressed in green fruit, accumulating as the fruit turned from green to white and remaining at an elevated, constant level throughout fruit ripening. In contrast, the Cel1 transcript was not detected in green fruit and only a low level of expression was observed in white fruit. The level of Cel1 mRNA increased gradually during ripening, reaching a maximum in fully ripe fruit. The high levels ofCel1 and Cel2 mRNA in ripe fruit and their overlapping patterns of expression suggest that these EGases play an important role in softening during ripening. In addition, the early expression of Cel2 in green fruit, well before significant softening begins, suggests that the product of this gene may also be involved in processes other than fruit softening, e.g. cell wall expansion.
Structure of β-trimyristin and β-tristearin from high-resolution X-ray powder diffraction data
Authors: van Langevelde Arjen , Peschar René , Schenk Henk 
Published: July 2002

The crystal structures of β-1,2,3-tritetradecanoylglycerol (β-trimyristin or β-MMM) and β-1,2,3-trioctadecanoylglycerol (β-tristearin or β-SSS) have been determined from high-resolution synchrotron X-ray powder diffraction data. Grid search and Rietveld refinement have been used to determine and refine the structure, respectively. Both substances crystallize in space group P\bar 1 with Z = 2. The unit-cell parameters for β-MMM are a = 12.0626 (6), b = 41.714 (1), c = 5.4588 (3) Å, α = 73.388 (4), β = 100.408 (5) and γ = 118.274 (4)°. For β-SSS the unit-cell parameters are a = 12.0053 (7), b = 51.902 (2), c = 5.4450 (3) Å, α = 73.752 (5), β = 100.256 (6) and γ = 117.691 (5)°. Soft-distance restraints have been applied to the molecules during refinement. For β-MMM the final Rp
value obtained is 0.053 and for β-SSS the final Rp
value is 0.041.
Structure refinement of Cu8GeS6 using X-ray diffraction data from a multiple-twinned crystal
Authors: Onoda Mitsuko , Chen Xue-An , Kato Katsuo , Sato Akira , Wada Hiroaki 
Published: July 2002

The structure of the orthorhombic room-temperature phase of Cu8GeS6 (copper germanium sulfide), Mr
= 773.27, has been refined on the basis of X-ray diffraction data from a 12-fold twinned crystal applying a six-dimensional twin refinement technique. For 1804 unique reflections measured using Mo Kα radiation, RF
was 0.083 with 77 structure parameters and 12 scale factors. The symmetry operations, the unit cell and other crystal data are (0, 0, 0; ½, ½, 0) + x, y, z; y, x, z; ¼ − x, ¾ − y, ½ + z; ¾ − y, ¼ − x, ½ + z; a = b = 9.9073 (3) Å, c = 9.8703 (4) Å, α = β = 90°, γ = 90.642 (4)°; V = 968.7 (1) Å3, Z = 4, Dx
= 5.358 Mg m−3, μ = 21.70 mm−1. The standard setting of the space group and the reduced unit cell are Pmn21; a = 7.0445 (3), b = 6.9661 (3), c = 9.8699 (5) Å; Z = 2.
Crystallization and preliminary X-ray diffraction data of the complex of recombinant tick anticoagulant peptide (rTAP) and bovine factor Xa
Authors: Wei Anzhi , Smallwood Angela , Alexander Richard S. , Duke Jodie , Ross Harold , Rosenfeld Stuart A. , Chang Chong-Hwan 
Published: July 2002

The complex of bovine factor Xa and recombinant tick anticoagulant peptide (rTAP) was crystallized in two different crystal forms using polyethylene glycol as a precipitant. Form I belongs to space group P42212 with unit-cell dimensions a = b = 133.1, c = 68.8 Å. It contains one complex per asymmetric unit and diffracts to 3.0 Å resolution. Form II belongs to P41212 (or P43212) with dimensions a = b = 126.5, c = 146.7 Å; it contains two complexes per asymmetric unit and diffracts to 2.5 Å. The crystals of both forms consist of factor Xa (MW
= 45.3 kDa) and rTAP (MW
= 6.7 kDa).
How RhoGDI binds Rho
Authors: Longenecker Kenton , Read Paul , Derewenda Urszula , Dauter Zbigniew , Liu Xiaopu , Garrard Sarah , Walker Lori , Somlyo Avril V. , Nakamoto Robert K. , Somlyo Andrew P. , Derewenda Zygmunt S. 
Published: July 2002

Like all Rho (Ras homology) GTPases, RhoA functions as a molecular switch in cell signaling, alternating between GTP- and GDP-bound states, with its biologically inactive GDP-bound form maintained as a cytosolic complex with RhoGDI (guanine nucleotide-exchange inhibitor). The crystal structures of RhoA–GDP and of the C-terminal immunoglobulin-like domain of RhoGDI (residues 67–203) are known, but the mechanism by which the two proteins interact is not known. The functional human RhoA–RhoGDI complex has been expressed in yeast and crystallized (P6522, unit-cell parameters a = b = 139, c = 253 Å, two complexes in the asymmetric unit). Although diffraction from these crystals extends to 3.5 Å and is highly anisotropic, the experimentally phased (MAD plus MIR) electron-density map was adequate to reveal the mutual disposition of the two molecules. The result was validated by molecular-replacement calculations when data were corrected for anisotropy. Furthermore, the N-terminus of RhoGDI (the region involved in inhibition of nucleotide exchange) can be identified in the electron-density map: it is bound to the switch I and switch II regions of RhoA, occluding an epitope which binds Dbl-like nucleotide-exchange factors. The entrance of the hydrophobic pocket of RhoGDI is 25 Å from the last residue in the RhoA model, with its C-terminus oriented to accommodate the geranylgeranyl group without conformational change in RhoA.
Microdroplet generation in liquid metal ion sources
Authors: Vladimirov V. V. , Badan V. E. , Gorshkov V. N. , Grechko L. G. , Soloshenko I. A. 
Published: July 2002

When the liquid metal ion sources (LMIS) operate in the high-current mode, an instability arises which is accompanied by ion current oscillations and microdroplets emission [Mair and Engel (1979), Sudraud et al. (1982, 1985)]. Two groups of microdroplets are observed differing in size, i.e., large ones (with radius of 2×102 to 2×103 Å) and small ones (with a radius of 10–100 Å). The intensity of small-scale droplet formation proves to be two or three orders of magnitude higher than that of the large droplets [Thompson (1982)]. In this work it is shown that the appearance of the above groups of microdroplets is due to two instabilities developed in LMIS. The small droplets are due to the Rayleigh instability on the surface of thin cylindrical jets ejected from the tip of the Taylor cone at higher currents. This instability results in jet fragmentation and formation of small droplets (with sizes of the order of the jet radius) till the jet completely disappears.
The recovery of the jets occurs within the time interval necessary for the most charged droplets to move towards the extractor as the screening effect of the droplets fades out and the electric field distribution on the cone surface is recovered. When the above time interval elapses the jet ejection reappears from the tip of the Taylor cone, and the jet fragmentation process is repeated. Thus, the Rayleigh instability is accompanied by the comparatively low-frequency ion current oscillations which are due to the process of fragmentation and recovery of the jets (f≂107 Hz). This process leads to liquid metal pressure modulation and causes the comparatively large-scale capillary wave extension on the Taylor cone surface (wavelength ≂104 Å) as a result of the Faraday parametrical effect. It is this effect that leads to formation of the large droplets generated on the Taylor cone surface. Emission of the small droplets occurs only in the cone axis direction, and that of the large droplets in a wider angular range.
We have made measurements of the angular distributions of the large and small droplets, as well as of their intensities in the instability mode (I=120 μA, f≂10 MHz) in tin LMIS. The intensity of small droplet generation (with a radius of 15–100 Å) is approximately 1010–1011 s−1 and that of large droplet generation is two to three orders of magnitude less. The computed intensity values approached the ones observed. The small droplets are emitted mainly along the LMIS axis but as to the large ones, a wider spatial spread is observed. The measurements were carried out with transmission electron microscopy (TEM).
Flow Cytometry Antifungal Susceptibility Testing of Pathogenic Yeasts other than
Candida albicans
and Comparison with the NCCLS Broth Microdilution Test
Authors: Ramani Rama , Chaturvedi Vishnu 
Published: July 2002

ABSTRACT

Candida
species other than
Candida albicans
frequently cause nosocomial infections in immunocompromised patients. Some of these pathogens have either variable susceptibility patterns or intrinsic resistance against common azoles. The availability of a rapid and reproducible susceptibility-testing method is likely to help in the selection of an appropriate regimen for therapy. A flow cytometry (FC) method was used in the present study for susceptibility testing of
Candida glabrata
,
Candida guilliermondii
,
Candida krusei
,
Candida lusitaniae
,
Candida parapsilosis
,
Candida tropicalis
, and
Cryptococcus neoformans
based on accumulation of the DNA binding dye propidium iodide (PI). The results were compared with MIC results obtained for amphotericin B and fluconazole using the NCCLS broth microdilution method (M27-A). For FC, the yeast inoculum was prepared spectrophotometrically, the drugs were diluted in either RPMI 1640 or yeast nitrogen base containing 1% dextrose, and yeast samples and drug dilutions were incubated with amphotericin B and fluconazole, respectively, for 4 to 6 h. Sodium deoxycholate and PI were added at the end of incubation, and fluorescence was measured with a FACScan flow cytometer (Becton Dickinson). The lowest drug concentration that showed a 50% increase in mean channel fluorescence compared to that of the growth control was designated the MIC. All tests were repeated once. The MICs obtained by FC for all yeast isolates except
C. lusitaniae
were in very good agreement (within 1 dilution) of the results of the NCCLS broth microdilution method. Paired
t
test values were not statistically significant (
P
= 0.377 for amphotericin B;
P
= 0.383 for fluconazole). Exceptionally,
C. lusitaniae
isolates showed higher MICs (2 dilutions or more) than in the corresponding NCCLS broth microdilution method for amphotericin B. Overall, FC antifungal susceptibility testing provided rapid, reproducible results that were statistically comparable to those obtained with the NCCLS method.
New TEM Variant (TEM-92) Produced by
Proteus mirabilis
and
Providencia stuartii
Isolates
Authors: de Champs Christophe , Monne Claire , Bonnet Richard , Sougakoff Wladimir , Sirot Danielle , Chanal Catherine , Sirot Jacques 
Published: July 2002

ABSTRACT

The sequences of the
bla
TEM
genes encoding TEM-92 in
Proteus mirabilis
and
Providencia stuartii
isolates were determined and were found to be identical. Except for positions 218 (Lys-6) and 512 (Lys-104), the nucleotide sequence of
bla
TEM-92
was identical to that of
bla
TEM-20
, including the sequence of the promoter region harboring a 135-bp deletion combined with a G-162→T substitution. The deduced amino acid sequence of TEM-92 differed from that of TEM-52 by the presence of a substitution (Gln-6→Lys) in the peptide signal.
In Vitro Activities of Four Novel Triazoles against
Scedosporium
spp
Authors: Carrillo A. J. , Guarro J. 
Published: July 2002

ABSTRACT

In order to develop new approaches to the treatment of the severe and usually fatal infections caused by
Scedosporium
spp., the in vitro antifungal activities of four novel triazoles (posaconazole, ravuconazole, voriconazole, and UR-9825) and some current antifungals (amphotericin B, ketoconazole, itraconazole, and nystatin) were determined. The latter group was clearly ineffective against the two species tested. The four new antifungals showed activity against
Scedosporium apiospermum
, and UR-9825 and voriconazole were active against
S. prolificans
.
Cloning and Biochemical Characterization of a Class A β-Lactamase from
Prevotella intermedia
Authors: Madinier I. , Fosse T. , Giudicelli J. , Labia R. 
Published: July 2002

ABSTRACT

The gene encoding a β-lactamase of
Prevotella intermedia
was cloned and sequenced. This gene, called
cfxA2
, shared 98% identity with
cfxA
, the structural gene of a β-lactamase previously described in
Bacteroides vulgatus
. The deduced protein sequence had a K272E substitution. CfxA2 had the characteristics of class A, group 2e β-lactamases.
Structural Analysis of Chloroquine Resistance Reversal by Imipramine Analogs
Authors: Bhattacharjee Apurba K. , Kyle Dennis E. , Vennerstrom Jonathan L. 
Published: July 2002

ABSTRACT
For imipramine, desipramine, and eight analogs of these well-known drugs, an N-5-aminoalkyl substitution was a minimum but insufficient structural feature associated with chloroquine resistance reversal. Although a second distal aliphatic nitrogen atom was unnecessary for resistance reversal, the direction of the dipole moment vector was critical.
Quinolone-Binding Pocket of DNA Gyrase: Role of GyrB
Authors: Heddle Jonathan , Maxwell Anthony 
Published: July 2002

ABSTRACT

DNA gyrase is a prokaryotic type II topoisomerase and a major target of quinolone antibacterials. The majority of mutations conferring resistance to quinolones arise within the quinolone resistance-determining region of GyrA close to the active site (Tyr
122
) where DNA is bound and cleaved. However, some quinolone resistance mutations are known to exist in GyrB. Present structural data suggest that these residues lie a considerable distance from the quinolone resistance-determining region, and it is not obvious how they affect quinolone action. We have made and purified two such mutant proteins, GyrB(Asp
426
→Asn) and GyrB(Lys
447
→Glu), and characterized them in vitro. We found that the two proteins behave similarly to GyrA quinolone-resistant proteins. We showed that the mutations exert their effect by decreasing the amount of quinolone bound to a gyrase-DNA complex. We suggest that the GyrB residues form part of a quinolone-binding pocket that includes DNA and the quinolone resistance-determining region in GyrA and that large conformational changes during the catalytic cycle of the enzyme allow these regions to come into close proximity.