bluuebunny/crossref_metadata_2025 huggingface dataset:
Cervical length at 11–14 weeks' and 22–24 weeks' gestation evaluated by transvaginal sonography, and gestational age at delivery
Authors: Carvalho M. H. B. , Bittar R. E. , Brizot M. L. , Maganha P. P. S. , Borges Da Fonseca E. S. V. , Zugaib M.
Published: March 2003

Objective

To compare cervical length measurements obtained at 11 to 14 weeks and 22 to 24 weeks of gestation in an unselected group of pregnant women and to correlate the measurements with time of delivery.

Methods

This was a prospective study involving 529 pregnant women attending for routine antenatal care who underwent transvaginal scans at 11–14 weeks and 22–24 weeks for evaluation of cervical length. The mean cervical length was calculated at both stages of gestation and lengths were compared between groups which delivered at term or prematurely, this being defined as delivery before 37 completed weeks of gestation.

Results

The mean cervical lengths at 11–14 and 22–24 weeks were, respectively, 42.4 mm and 38.6 mm. Cervical length at 11–14 weeks was not significantly different between the groups which delivered at term (42.7 mm) and preterm (40.6 mm). However, at the 22–24‐week evaluation, cervical length was significantly shorter in the group which had a preterm delivery than in that which had a term delivery (26.7 mm and 39.3 mm, respectively; P = 0.0001). In the group of women with a previous history of one or more preterm deliveries, there was a greater shortening in cervical length from the first to the second evaluation than there was in the group of women with no previous history of preterm delivery. This shortening was also more pronounced in the group which delivered prematurely (from 40.6 mm to 26.7 mm) than in that which delivered at term (from 42.7 mm to 39.3 mm).

Conclusion

There is a spontaneous shortening in the pregnant cervix from the first to the second trimester of pregnancy. The shortening is more rapid in pregnant women who deliver prematurely and who have a history of previous preterm delivery. Copyright © 2003 ISUOG. Published by John Wiley & Sons, Ltd.
Nasal bone length throughout gestation: normal ranges based on 3537 fetal ultrasound measurements
Authors: Sonek J. D. , Mckenna D. , Webb D. , Croom C. , Nicolaides K.
Published: March 2003

Objective

To establish normal ranges for nasal bone length measurements throughout gestation and to compare measurements in two subsets of patients of different race (African‐American vs. Caucasian) to determine whether a different normal range should be used in these populations.

Method

Normal nasal bone length reference ranges were generated using prenatal measurements by a standardized technique in 3537 fetuses.

Results

The nasal bone lengths were found to correlate positively with advancing gestation (R2 = 0.77, second‐order polynomial). No statistical difference was found between African‐American and Caucasian subjects.

Conclusion

These reference ranges may prove to be useful in prenatal screening and diagnosis of syndromes known to be associated with nasal hypoplasia. Different normal ranges for African‐American and Caucasian women are not required. Copyright © 2003 ISUOG. Published by John Wiley & Sons, Ltd.
Four ARF GAPs in Saccharomyces cerevisiae have both overlapping and distinct functions
Authors: Zhang Chun‐Jiang , Bowzard J. Bradford , Anido Aimee , Kahn Richard A.
Published: March 2003

Previous studies in yeast have revealed the presence of four proteins with a conserved, cysteine‐rich, ARF GAP domain that share the ability to suppress the conditional growth defect of the arf1‐3 mutant. Three of these proteins have been shown previously to be ADP‐ribosylation factor (ARF) GTPase‐activating proteins (GAPs). We now demonstrate that the fourth also exhibits in vitro ARF GAP activity and correlates the suppressor and ARF GAP activities for all four. Because the four ARF GAP proteins are quite diverse outside the ARF GAP domain, a genetic analysis was undertaken to define the level of functional cross‐talk between them. A large number of synthetic defects were observed that point to a high degree of functional overlap among the four ARF GAPs. However, several differences were also noted in the ability of each gene to suppress the synthetic defects of others and in the impact of single or combined deletions on assays of membrane traffic. We interpret these results as supportive evidence for roles of ARF GAPs in a number of distinct, essential cellular processes that include cell growth, protein secretion, endocytosis and cell cycling. The description of the specificities of the ARF GAPs for the different responses is viewed as a necessary first step in dissecting biologically relevant pathways through a functionally overlapping family of signalling proteins. Copyright © 2003 John Wiley & Sons, Ltd.
Cyclic AMP mediates the cell cycle dynamics of energy metabolism in Saccharomyces cerevisiae
Authors: Müller Dirk , Exler Simone , Aguilera‐Vázquez Luciano , Guerrero‐Martín Ester , Reuss Matthias
Published: March 2003

We have investigated the role of 3′,5′‐cyclic‐adenosine‐monophosphate (cAMP) in mediating the coupling between energy metabolism and cell cycle progression in both synchronous cultures and oscillating continuous cultures of Saccharomyces cerevisiae. For the first time, a peak in intracellular cAMP was shown to precede the observed breakdown of trehalose and glycogen during cell cycle‐related oscillations. Measurements in synchronous cultures demonstrated that this peak can be associated with the cell cycle dynamics of cAMP under conditions of glucose‐limited growth, which was found to differ significantly from that observed in synchronous glucose‐repressed cultures. Our results support the notion that cAMP plays a major role in mediating the integration of energy metabolism and cell cycle progression, both in the single cell and during cell cycle‐related oscillations in continuous culture, respectively. Evidence is presented that the dynamic behaviour of intracellular cAMP during the cell cycle is modulated depending on nutrient supply. The implications of these findings regarding the role of cAMP in regulating cell cycle progression and energy metabolism are discussed. Copyright © 2003 John Wiley & Sons, Ltd.
Topochemically Controlled Redox Reactions in the System In/Sn/Cl
Authors: Beck Horst P. , Becker Daniel
Published: March 2003

The difference in reactivity of the two modifications of InCl in solid state reactions with SnCl2 is discussed. It is explained on the basis of semi‐empirical and ab initio calculations giving the density of states diagrams of InCl and the energies of possible disproportionation reactions. Their general features are discussed on the basis of a simple bonding picture for open‐packed structures involving inert pair elements. A detailed analysis of the DOS distribution allows to pinpoint the observed redox instability to a specific structural feature of α‐InCl.
Pressure‐induced Changes of the Crystal Structure of Eu4P3
Authors: Cardoso‐Gil R. , Niewa R. , Schmidt M. , Armbrüster M. , Hanfland M. , Klementiev K. , Schwarz Ulrich
Published: March 2003

Pressure‐induced structural changes and electronic properties of rhombohedral Eu4P3 were characterised by means of X‐ray powder diffraction and X‐ray absorption spectroscopy at the Eu LIII threshold. The measurements at low pressures indicate oxidation states of the europium atoms which are compatible with a composition Eu32+Eu3+P3. At a pressure of 8(1) GPa, Eu4P3 undergoes a structural phase transition. The cubic high pressure modification with (anti‐)Th3P4 type crystal structure is also identified as a compound with a non‐integer average oxidation state of the europium atoms.
Structure and Bonding of the Hexameric Platinum(II) Dichloride, Pt6Cl12 (β‐PtCl2)
Authors: von Schnering Hans Georg , Chang Jen‐Hui , Peters Karl , Peters Eva‐Maria , Wagner Frank R. , Grin Yuri , Thiele Gerhard
Published: March 2003

The crystal structure of Pt6Cl12 (β‐PtCl2) was redetermined ($R \bar 3 m$ ah = 13.126Å, ch = 8.666Å, Z = 3; arh = 8.110Å, α = 108.04°; 367 hkl, R = 0.032). As has been shown earlier, the structure is in principle a hierarchical variant of the cubic structure type of tungsten (bcc), which atoms are replaced by the hexameric Pt6Cl12 molecules. Due to the 60° rotation of the cuboctahedral clusters about one of the trigonal axes, the symmetry is reduced from $Im \bar 3 m$ to $R \bar 3 m$ ($I \bar 3 m$). The molecule Pt6Cl12 shows the (trigonally elongated) structure of the classic M6X12 cluster compounds with (distorted) square‐planar PtCl4 fragments, however without metal‐metal bonds. The Pt atoms are shifted outside the Cl12 cuboctahedron by Δ = +0.046Å ($\bar {\rm d}$(Pt—Cl) = 2.315Å; $\bar {\rm d}$(Pt—Pt) = 3.339Å). The scalar relativistic DFT calculations results in the full $m \bar 3 m$ symmetry for the optimized structure of the isolated molecule with d(Pt—Cl) = 2.381Å, d(Pt—Pt) = 3.468Å and Δ = +0.072Å. The electron distribution of the Pt‐Pt antibonding HOMO exhibits an outwards‐directed asymmetry perpendicular to the PtCl4 fragments, that plays the decisive role for the cluster packing in the crystal. A comparative study of the Electron Localization Function with the hypothetical trans‐(Nb2Zr4)Cl12 molecule shows the distinct differences between Pt6Cl12 and clusters with metal‐metal bonding. Due to the characteristic electronic structure, the crystal structure of Pt6Cl12 in space group $R \bar 3 m$ is an optimal one, which results from comparison with rhombohedral Zr6I12 and a cubic bcc arrangement.
Von kleinen Bausteinen zu neuen Poly‐alkoxo‐oxometallat‐Derivaten: Synthese und Strukturaufklärung von K4[VIV12O12(OCH3)16(C4O4)6], Cs10[VIV24O24(OCH3)32(C4O4)12][VIV8O8(OCH3)16(C2O4)] und M2[VIV8O8(OCH3)16(VIVOF4)] (M = [N(nBu)4] bzw. [NEt4])
Authors: Spandl Johann , Brüdgam Irene , Hartl Hans
Published: March 2003

Durch Umsetzung von ortho‐Vanadinsäuremethylester [VO(OMe)3] mit Quadratsäure und Kalium‐ bzw. Caesiumhydroxid konnten unter Solvothermalbedingungen die Verbindungen K4[VIV12O12(OCH3)16(C4O4)6] (2) und Cs10[VIV24O24(OCH3)32(C4O4)12][VIV8O8(OCH3)16(C2O4)] (3) synthetisiert werden. Mit Tetra‐n‐butyl‐ bzw. Tetra‐n‐ethylammoniumfluorid erhält man [N(nBu)4]2[VIV8O8(OCH3)16(VIVOF4)] (4) und [N(Et)4]2[VIV8O8(OCH3)16(VIVOF4)] (5). In den Verbindungen 2 und 3 sind an den Ecken eines Tetraeders bzw. Würfels sitzende {(VO)3(OMe)4}‐Gruppen entlang der Tetraeder‐ bzw. Würfelkanten über sechs bzw. zwölf Quadratatogruppen miteinander verknüpft. Die achtkernigen Anionen in den Verbindungen 3, 4 und 5 kann man sich aus oligomeren, kettenförmigen Fragmenten des Vanadinsäuremethylesters, die sich um die Anionen C2O42— oder VOF4— zum Ring schliessen, aufgebaut denken.

Kristalldaten: 2, tetragonal, P43, a = 18, 166(3)Å, c = 29, 165(7)Å, V = 9625(3)Å3, Z = 4, dc = 1, 469 gcm—3; 3, orthorhombisch, Pbca, a = 29, 493(5)Å, b = 25, 564(4)Å, c = 31, 076Å, V = 23430(6)Å3, Z = 4, dc = 1, 892 gcm—3; 4, monoklin, P21/n, a = 9, 528(1)Å, b = 23, 021(2)Å, c = 19, 303(2)Å, β = 92, 570(2)°, V = 4229, 8(5)Å3, Z = 2, dc = 1, 391 gcm—3; 5, monoklin, P21/n, a = 16, 451(2)Å, b = 8, 806(1)Å, c = 23, 812(1)Å, β = 102, 423(2)°, V = 3368, 7(6)Å3, Z = 2, dc = 1, 534 gcm—3.
Endothelium-Derived Relaxing Factor: Discovery, Early Studies, and Identification as Nitric Oxide
Authors: Furchgott Robert F.
Published: March 2003

The discovery, early studies and identification of endothelium-derived relaxing factor (EDRF) as nitric oxide, are described.
Role of Glycosphingolipids in HIV-1 Entry: Requirement of Globotriosylceramide (Gb3) in CD4/CXCR4-dependent Fusion
Authors: Puri Anu , Hug Peter , Jernigan Kristine , Rose Patrick , Blumenthal Robert
Published: March 2003

We have recently shown that addition of human erythrocyte glycosphingolipids (GSL) to non-human CD4+ or GSL-depleted human CD4+ cells rendered those cells susceptible to gp120-gp41-mediated cell fusion (Puri et al., BBRC, 1998). One GSL fraction (Fraction 3) isolated from human erythrocyte GSL mixture exhibited the highest recovery of fusion following incorporation into CD4+ non-human and GSL-depleted HeLa-CD4 cells (HeLa-CD4/GSL-). Structural analysis of Fraction 3 showed that this GSL had identical head group as the known GSL, Gal(α1→4)Gal(β1→4)Glc-Ceramide (Gb3) (Puri et al., PNAS, 1998). Here we report that presence of Gb3 in CD4+/CXCR4+ cells but not CD4+/CXCR4- cells allows fusion with HIV-1Lai-envelope glycoprotein expressing cells (TF228). Therefore, Gb3 functions in conjunction with HIV-1 co-receptor, CXCR4 to promote fusion. We propose that Gb3 functions by recruiting CD4 and/or CXCR4 at the fusion site through structurally specific interactions.
Interactions at the Membrane Surface Studied by Spin Label ESR Spectroscopy
Authors: Marsh Derek
Published: March 2003

A range of different types of interactions at biological membrane surfaces have been studied using various different spin label electron spin resonance (ESR) techniques. These include: (1) the interfacial ionization of local anaesthetics, (2) the binding of peripheral membrane proteins, (3) the membrane insertion of translocation-competent precursor proteins and other components of the protein translocation machinery, (4) the interactions of ganglioside sphingolipids with membrane proteins, and (5) the specific surface recognition of biotinylated phospholipid headgroups by avidin. A description of these illustrates both the capabilities of this biophysical methodology and the functional/technological implications of these interactions and dynamic/thermodynamic processes for cell membranes and their surfaces.
The Staminal Lever Mechanism in Salvia L. (Lamiaceae) ‐ a Review
Authors: Claβen‐Bockhoff R. , Wester P. , Tweraser E.
Published: March 2003

Abstract: The genus Salvia encompasses about 900 species distributed world‐wide. It is characterized by the famous staminal lever mechanism of the flower which is one of the best known examples of a nototribic pollination mechanism. We hypothesize that structure and functioning of the staminal levers play a major role as key structures in speciation. To cope with the complex evolutionary processes involved, a number of different methodological approaches are needed. The present paper summarizes the literature referring to structural and functional diversity, breeding systems, systematics and evolution in Salvia.
The Diversity of Self‐Incompatibility Systems in Flowering Plants
Authors: Hiscock S. J. , McInnis S. M.
Published: March 2003

Abstract: Flowering plants are the most successful group of land plants and dominate the earth's vegetation with around 300 000 species. This success is, in part, the consequence of a set of unique reproductive innovations that evolved with the flower. Most notable of these innovations were the closed carpel and double fertilization. Closed carpels permitted the evolution of effective mechanisms for pollen selection and discrimination, while double fertilization leading to endosperm formation allowed for more efficient utilization of resources because reserves are only allocated to the seed after fertilization. This review will focus on the most important and best understood mechanism of pollen discrimination, self‐incompatibility (SI), a genetically determined pollen recognition system that prevents self‐fertilization and fertilization by other individuals with the same incompatibility phenotype. In recent years much progress has been made towards elucidating the molecular mechanisms of SI operating in three distinct SI systems found in the Brassicaceae, Solanaceae and Papaveraceae, respectively. More recent molecular data obtained from the Poaceae, Convolvulaceae and Asteraceae, however, suggest that other molecular mechanisms of SI exist. A survey of classical genetic studies of SI predicts yet further potential molecular mechanisms of SI. We discuss the evolutionary implications of this apparent diversity in molecular pathways leading to SI and stress the need for more molecular studies of different SI systems.
Liquid–liquid phase transition in compressed hydrogen from first-principles simulations
Authors: Scandolo Sandro
Published: March 2003

The properties of compressed liquid hydrogen, the most abundant fluid in the universe, have been investigated by means of first-principles molecular dynamics at pressures between 75 and 175 GPa and temperatures closer to the freezing line than so far reported in shock-wave experiments. Evidence for a liquid–liquid transition between a molecular and a dissociated phase is provided. The transition is accompanied by a 6% increase in density and by metallization. This finding has important implications for our understanding of the interiors of giant planets and supports predictions of a quantum fluid state at low temperatures.
Liver-specific mRNA for Insig-2 down-regulated by insulin: Implications for fatty acid synthesis
Authors: Yabe Daisuke , Komuro Ryutaro , Liang Guosheng , Goldstein Joseph L. , Brown Michael S.
Published: March 2003

Insig-1 and -2 are closely related proteins of the endoplasmic reticulum (ER) that block proteolytic activation of sterol regulatory element-binding proteins (SREBPs), transcription factors that activate the synthesis of cholesterol and fatty acids in liver and other organs. When cellular cholesterol levels are high, Insig proteins bind and trap SREBP cleavage-activating protein (SCAP), retaining it in the ER and preventing it from escorting SREBPs from ER to the site of proteolytic activation in the Golgi complex. Here, we report the discovery of a liver-specific transcript of Insig-2, designated Insig-2a. This transcript and the ubiquitous transcript, designated Insig-2b, differ through the use of different promoters that produce different noncoding first exons that splice into a common second exon. Although the Insig-2a and -2b mRNAs encode identical proteins, they differ in patterns of regulation. Insig-2a is the predominant transcript in livers of fed animals, and it is selectively down-regulated by insulin. Insig-2a mRNA increases when mice are fasted, and it declines when they are refed. The transcript also increases in livers of rats whose insulin-secreting pancreatic beta cells have been destroyed by streptozotocin, and it is reduced when insulin is injected. The insulin-mediated fall in Insig-2a may allow SREBP-1c to be processed, thereby allowing insulin to stimulate fatty acid synthesis, even under conditions in which hepatic cholesterol levels are elevated.
The power of human brain magnetoencephalographic signals can be modulated up or down by changes in an attentive visual task
Authors: Chen Yanqing , Seth Anil K. , Gally Joseph A. , Edelman Gerald M.
Published: March 2003

This paper presents evidence indicating that the signals generated by neural responses to visual input can be either enhanced by increasing or suppressed by decreasing the area of the stimuli to which attention is directed. We used magnetoencephalography (MEG) to measure the frequency-tagged steady-state visual evoked responses of 11 subjects presented with two superimposed images flickering at different frequencies. Each image consisted of seven parallel bars of equal length; in any image, all bars were either red or green and either horizontal or vertical. At randomly chosen times during the experiments, any one of the three middle bars in either image transiently increased or decreased in width. Subjects were asked to attend to one image and ignore the other and to respond to changes in bar width in the attended image with a key press. In one condition, subject responses were required for changes in any of the three central bars of the attended image. We found that visual steady-state evoked responses to the attended image were enhanced relative to those evoked by the unattended image in this condition. In a second condition, subject responses were required for changes only in the middle bar. In this condition, the responses to the attended image were suppressed relative to those of the unattended image. These results may reflect relative differences in the synchronization and desynchronization of responding neuronal populations.
Nuclear georeactor origin of oceanic basalt
3
He/
4
He, evidence, and implications
Authors: Herndon J. Marvin
Published: March 2003

Nuclear georeactor numerical simulation results yield substantial
3
He and
4
He production and
3
He/
4
He ratios relative to air (
R
A
) that encompass the entire 2-SD (2σ) confidence level range of tabulated measured
3
He/
4
He ratios of basalts from along the global spreading ridge system. Georeactor-produced
3
He/
4
He ratios are related to the extent of actinide fuel consumption at time of production and are high near the end of the georeactor lifetime. Georeactor numerical simulation results and the observed high
3
He/
4
He ratios measured in Icelandic and Hawaiian oceanic basalts indicate that the demise of the georeactor is approaching. Within the present level of uncertainty, one cannot say precisely when georeactor demise will occur, whether in the next century, in a million years, or in a billion years from now.
Maternal induction of ventral fate by zebrafish
radar
Authors: Sidi Samuel , Goutel Carole , Peyriéras Nadine , Rosa Frédéric M.
Published: March 2003

In vertebrate embryos, maternal determinants are thought to preestablish the dorsoventral axis by locally activating zygotic ventral- and dorsal-specifying genes, e.g., genes encoding bone morphogenetic proteins (BMPs) and BMP inhibitors, respectively. Whereas the canonical Wnt/β-catenin pathway fulfills this role dorsally, the existence of a reciprocal maternal ventralizing signal remains hypothetical. Maternal noncanonical Wnt/Ca
2+
signaling may promote ventral fates by suppressing Wnt/β-catenin dorsalizing signals; however, whether any maternal determinant is directly required for the activation of zygotic ventral-specifying genes is unknown. Here, we show that such a function is achieved, in part, in the zebrafish embryo by the maternally encoded transforming growth factor β (TGF-β) signaling molecule, Radar. Loss-of-function experiments, together with epistasis analyses, identify maternal Radar as an upstream activator of
bmps
expression. Maternal induction of
bmps
by Radar is essential for zebrafish development as its removal results in larval-lethal dorsalized phenotypes. Double-morphant analyses further suggest that Radar functions through the TGF-β receptor Alk8 to initiate the expression of
bmp
genes. Our results support the existence of a previously uncharacterized maternal ventralizing pathway. They might further indicate that maternal TGF-β/Rdr and Wnt/Ca
2+
pathways complementarily specify ventral cell fates, with the former triggering
bmps
expression and the latter indirectly repressing genes encoding BMP antagonists.
A binding motif for Siah ubiquitin ligase
Authors: House Colin M. , Frew Ian J. , Huang Huei-Luen , Wiche Gerhard , Traficante Nadia , Nice Edouard , Catimel Bruno , Bowtell David D. L.
Published: March 2003

The
Drosophila
SINA (seven in absentia) protein and its mammalian orthologs (Siah, seven in absentia homolog) are RING domain proteins that function in E3 ubiquitin ligase complexes and facilitate ubiquitination and degradation of a wide range of cellular proteins, including β-catenin. Despite these diverse targets, the means by which SINA/Siah recognize substrates or binding proteins has remained unknown. Here we identify a peptide motif (RPVAxVxPxxR) that mediates the interaction of Siah protein with a range of protein partners. Sequence alignment and mutagenesis scanning revealed residues that are important to this interaction. This consensus sequence correctly predicted a high-affinity interaction with a peptide from the cytoskeletal protein plectin-1 (residues 95–117). The unusually high-affinity binding obtained with a 23-residue peptide (
K
Dapp
= 29 nM with SINA) suggests that it may serve as a useful dominant negative reagent for SINA/Siah proteins.
Extending the definition of entropy to nonequilibrium steady states
Authors: Ruelle David P.
Published: March 2003

We study the nonequilibrium statistical mechanics of a finite classical system subjected to nongradient forces ξ and maintained at fixed kinetic energy (Hoover–Evans isokinetic thermostat). We assume that the microscopic dynamics is sufficiently chaotic (Gallavotti–Cohen chaotic hypothesis) and that there is a natural nonequilibrium steady-state ρ
ξ
. When ξ is replaced by ξ + δξ, one can compute the change δρ of ρ
ξ
(linear response) and define an entropy change δ
S
based on energy considerations. When ξ is varied around a loop, the total change of
S
need not vanish: Outside of equilibrium the entropy has curvature. However, at equilibrium (i.e., if ξ is a gradient) we show that the curvature is zero, and that the entropy
S
(ξ + δξ) near equilibrium is well defined to second order in δξ.
Integrating regulatory motif discovery and genome-wide expression analysis
Authors: Conlon Erin M. , Liu X. Shirley , Lieb Jason D. , Liu Jun S.
Published: March 2003

We propose
motif regressor
for discovering sequence motifs upstream of genes that undergo expression changes in a given condition. The method combines the advantages of matrix-based motif finding and oligomer motif-expression regression analysis, resulting in high sensitivity and specificity.
motif regressor
is particularly effective in discovering expression-mediating motifs of medium to long width with multiple degenerate positions. When applied to
Saccharomyces cerevisiae
,
motif regressor
identified the ROX1 and YAP1 motifs from Rox1p and Yap1p overexpression experiments, respectively; predicted that Gcn4p may have increased activity in
YAP1
deletion mutants; reported a group of motifs (including GCN4, PHO4, MET4, STRE, USR1, RAP1, M3A, and M3B) that may mediate the transcriptional response to amino acid starvation; and found all of the known cell-cycle regulation motifs from 18 expression microarrays over two cell cycles.
Coadministration of HIV vaccine vectors with vaccinia viruses expressing IL-15 but not IL-2 induces long-lasting cellular immunity
Authors: Oh SangKon , Berzofsky Jay A. , Burke Donald S. , Waldmann Thomas A. , Perera Liyanage P.
Published: March 2003

Vaccine efficacy is determined largely by cellular and humoral immunity as well as long-lasting immunological memory. IL-2 and IL-15 were evaluated in vaccinia vectors expressing HIV gp160 for the establishment of an effective vaccine strategy. Both IL-2 and IL-15 in the vaccinia vector induced strong and long-lasting antibody-mediated immunity as well as a short-term cytotoxic T cell response against HIV gp120. In addition, IL-15 also supported robust CD8+T cell-mediated long-term immunity, whereas the CD8+T cell-mediated immunity induced by IL-2 was short-lived. Moreover, we found that the cytokine milieu at the time of priming had surprisingly persistent effects on the character of the memory CD8 T cells long afterward with respect to their fate, functional activities, cytokine receptor expression, and antigen-independent proliferation.
Loss of p16
INK4a
results in increased glucocorticoid receptor activity during fibrosarcoma development
Authors: Roca Ramon , Kypta Robert M. , Vivanco Maria d. M.
Published: March 2003

Glucocorticoids inhibit proliferation of many cell types, but the relationship between the glucocorticoid receptor (GR) and the proteins regulating cell cycle progression is not fully understood. We previously found that during fibrosarcoma (FS) progression, GR displays only modest transcriptional activity in the preneoplastic stages, whereas it is highly active in FS cells. Now, we report that glucocorticoids reduce proliferation throughout FS development. The cyclin-dependent kinase inhibitor p16
INK4a
is frequently absent in many cancers, including FSs. We observed that p16
INK4a
protein expression is lost at the tumor stage of FS progression. Treatment with the demethylating agent 5-aza-2′-deoxycytidine restores p16
INK4a
expression and reverts the phenotype of FS cells to low GR transcriptional activity, similar to that of the p16
INK4a
-expressing preneoplastic stages. Importantly, exogenous p16
INK4a
introduced by cotransfection is sufficient to reduce GR activity in FS cells, without affecting GR activity in p16-positive aggressive fibromatosis cells. Furthermore, GR transcriptional activity is elevated in mouse embryo fibroblasts derived from INK4a
−/−
mice compared with those derived from WT mice, implying that the difference in p16
INK4a
expression is sufficient to modulate GR activity. These results suggest a relationship between steroid hormone receptor activity and cell cycle inhibition, whereby absence of p16
INK4a
protein leads to higher GR transactivation activity and reduced cell sensitivity to dexamethasone. This observation might have important implications for current cancer therapies.
Conditional tradeoffs between aging and organismal performance of
Indy
long-lived mutant flies
Authors: Marden James H. , Rogina Blanka , Montooth Kristi L. , Helfand Stephen L.
Published: March 2003

Alterations that extend the life span of animals and yeast typically involve decreases in metabolic rate, growth, physical activity, and/or early-life fecundity. This negative correlation between life span and the ability to assimilate and process energy, to move, grow, and reproduce, raises questions about the potential utility of life span extension. Tradeoffs between early-life fitness and longevity are central to theories of the evolution of aging, which suggests there is necessarily a price to be paid for reducing the rate of aging. It is not yet clear whether life span can be extended without undesirable effects on metabolism and fecundity. Here, we report that the long-lived
Indy
mutation in
Drosophila
causes a decrease in the slope of the mortality curve consistent with a slowing in the rate of aging without a concomitant reduction in resting metabolic rate, flight velocity, or age-specific fecundity under normal rearing conditions. However,
Indy
mutants on a decreased-calorie diet have reduced fecundity, suggesting that a tradeoff between longevity and this aspect of performance is conditional, i.e., the tradeoff can occur in a stressful environment while being absent in a more favorable environment. These results provide evidence that there do exist mechanisms, albeit conditional, that can extend life span without significant reduction in fecundity, metabolic rate, or locomotion.
Intein-mediated assembly of a functional β-glucuronidase in transgenic plants
Authors: Yang Jianjun , Fox George C. , Henry-Smith Tina V.
Published: March 2003

The DnaE intein in
Synechocystis
sp. strain PCC6803 is the first and only naturally split intein that has been identified so far. It is capable of catalyzing a protein trans-splicing mechanism to assemble a mature protein from two separate precursors. Therefore, it is a powerful tool for protein modification and engineering. Inteins have not been identified, nor have intein-mediated protein splicing reactions been demonstrated, in plant cells. In this paper, we describe the use of the
Ssp
DnaE split intein in transgenic plants for reconstitution of a protein trans-splicing reaction. We have synthesized artificial genes that encode for N-terminal half (Int-n) and C-terminal half (Int-c) fragments of
Ssp
DnaE split intein and divided β-glucuronidase (
GUS
) gene to encode GUS-n and GUS-c parts of the enzyme as reporter. The in-frame fusions of GUSn/Intn and Intc/GUSc were constructed and transfected into
Arabidopsis
. We have observed
in vivo
reassembly of functional β-glucuronidase when both GUSn/Intn and Intc/GUSc constructs were introduced into the same
Arabidopsis
genome either by cotransformation or through genetic crossing, hereby signifying an intein-mediated protein trans-splicing mechanism reconstituted in plant cells.
Modifying the stereochemistry of an enzyme-catalyzed reaction by directed evolution
Authors: Williams Gavin J. , Domann Silvie , Nelson Adam , Berry Alan
Published: March 2003

Aldolases have potential as tools for the synthesis of stereochemically complex carbohydrates. Here, we show that directed evolution can be used to alter the stereochemical course of the reaction catalyzed by tagatose-1,6-bisphosphate aldolase. After three rounds of DNA shuffling and screening, the evolved aldolase showed an 80-fold improvement in
k
cat
/
K
m
toward the non-natural substrate fructose 1,6-bisphosphate, resulting in a 100-fold change in stereospecificity.
31
P NMR spectroscopy was used to show that, in the synthetic direction, the evolved aldolase catalyzes the formation of carbon—carbon bonds with unnatural diastereoselectivity, where the >99:<1 preference for the formation of tagatose 1,6-bisphosphate was switched to a 4:1 preference for the diastereoisomer, fructose 1,6-bisphosphate. This demonstration is of considerable significance to synthetic chemists requiring efficient syntheses of complex stereoisomeric products, such as carbohydrate mimetics.
Non-heme iron protein: A potential target of nitric oxide in acute cardiac allograft rejection
Authors: Pieper Galen M. , Halligan Nadine L. N. , Hilton Gail , Konorev Eugene A. , Felix Christopher C. , Roza Allan M. , Adams Mark B. , Griffith Owen W.
Published: March 2003

We examined iron nitrosylation of non-heme protein and enzymatic activity of the Fe-S cluster protein, aconitase, in acute cardiac allograft rejection. Heterotopic transplantation of donor hearts was performed in histocompatibility matched (isografts: Lewis → Lewis) and mismatched (allografts: Wistar–Furth → Lewis) rats. On postoperative days (POD) 4–6, Western blot analysis and immunohistochemistry revealed inducible nitric-oxide synthase (iNOS) protein in allografts but not isografts. EPR spectroscopy revealed background signals at
g
= 2.003 (for semiquinone) and
g
= 2.02 and
g
= 1.94 (for Fe-S cluster protein) in isografts and normal hearts. In contrast, in allografts on POD4, a new axial signal at
g
= 2.04 and
g
= 2.02 appeared that was attributed to the dinitrosyl–iron complex formed by nitrosylation of non-heme protein. Appearance of this signal occurred at or before significant nitrosylation of heme protein. Iron nitrosylation of non-heme protein was coincidental with decreases in the nonnitrosylated Fe-S cluster signal at
g
= 1.94. Aconitase enzyme activity was decreased to ≈50% of that observed in isograft controls by POD4. Treatment with cyclosporine blocked the (
i
) elevation of plasma nitrate + nitrite, (
ii
) up-regulation of iNOS protein, (
iii
) decrease in Fe-S cluster EPR signal, (
iv
) formation of dinitrosyl–iron complexes, and (
v
) loss of aconitase enzyme activity. Formation of dinitrosyl–iron complexes and loss of aconitase activity within allografts also was inhibited by treatment of recipients with a selective iNOS inhibitor,
l
-
N
6
-
(1-iminoethyl)lysine. This report shows targeting of an important non-heme Fe-S cluster protein in acute solid organ transplant rejection.
Positioning errors consideration for indoor mobile robot design
Authors: Louchene Ahmed , Eddine Bouguechal Nour
Published: March 2003

This paper deals with the design and implementation of an improved localization method. The study presented in this paper focuses on the displacement and heading errors. The technique proposed improves considerably on dead reckoning methods by reducing the systematic and non‐systematic errors. Detection of the floor irregularities is the main feature of the designed method in the correction of displacement errors. However, for internal errors correction, a trailing wheel is used. Following that, a predefined trajectory is provided by the control of the trailing wheel deviation angle.
Viscoelastic properties of threads before and after sewing
Authors: Ajiki Isao , Postle Ron
Published: March 2003

The viscoelastic properties of the sewing thread before and after loading in the sewing process were investigated. Sewing threads are subjected to dynamic tension and friction in the sewing process. In order to compare polyester, cotton and silk sewing threads, the fineness of the threads were selected to be almost equal. There are some differences between the stress extension curves of the parent thread and the sewn thread except for the polyester sewing thread. The phenomenon of inverse relaxation occurs for high levels of retraction. The stress‐inverse relaxation index for the polyester sewing thread is larger than for other threads and the inverse relaxation for silk thread is small. From the creep curves, the sewn threads show higher secondary creep and lower instantaneous recovery than the parent threads.
Mechanical properties of fabric materials for draping simulation
Authors: Wu Z. , Au C.K. , Yuen Matthew
Published: March 2003

Most of the cloth simulation and modelling techniques rely on the energy function of the system. The geometric deformation is related to the energy function by the fabric material characteristics, which are usually difficult to measure directly. This paper discusses how the fabric material properties are related to the measurable mechanical properties of the fabric such as tensile modulus, Poisson's ratio etc. These properties are incorporated into a cloth simulator to produce draping results. The simulated image and real object are then compared to show the realism.
A review of disaster and crisis
Authors: Shaluf Ibrahim M. , Ahmadun Fakharu’l‐razi , Mat Said Aini
Published: March 2003

A disaster and a crisis are two different, and related events. The two terms are sometimes used interchangeably. Man‐made disaster that occurs at an industrial organization, may develop into an industrial crisis. Crisis can happen to any organization. It has been noted that there were no universally accepted definitions yet developed for disaster and crisis. There is also no universally available criteria, to define the disaster in terms of the consequences, such as the casualties and the cost of damage. This paper reviews the definitions, types, characteristics, criteria and models of disaster and crisis. Also the types of crisis were rearranged and the differences between the disasters and crises have been summarized.
PARAMETER-INDUCED STOCHASTIC RESONANCE AND BASEBAND BINARY PAM SIGNALS TRANSMISSION OVER AN AWGN CHANNEL
Authors: DUAN FABING , XU BOHOU
Published: March 2003

From the point of information theory, the baseband binary pulse amplitude modulated (PAM) signals transmission, via tuning the nonlinear receiver's parameters, is studied over an additive white Gaussian noise (AWGN) channel. It is demonstrated that the channel capacity of baseband binary communication systems, for a given signal added noise, can be maximized by optimal designed receivers. This new form of stochastic resonance (SR) is referred to as parameter-induced stochastic resonance (PSR) in a broad sense. PSR effect does not require that the input signals are subthreshold. The characteristic behavior of channel capacity versus transmission bit rate is also studied. For reproducing the original binary signals more correctly, time scale transformation method and the approach of ensemble average probability of error bits are introduced. We observe a marked enhancement of the channel capacity for binary PAM signals transmission by PSR in numerical simulations. With this theory and method, the practical applications are considered.
CONTROLLERS FOR NONLINEAR SYSTEMS USING NORMAL FORMS
Authors: WALKER DAVID M. , FROYLAND GARY , JUDD KEVIN , MEES ALISTAIR I.
Published: March 2003

We describe a method for the design of feedback stabilization control laws for nonlinear systems using the theory of normal forms and the results from optimal control theory. We show that the resulting controllers can provide a larger region of stability than local linear controllers designed to perform the same task.
A SUITE OF DAML+OIL ONTOLOGIES TO DESCRIBE BIOINFORMATICS WEB SERVICES AND DATA
Authors: WROE CHRIS , STEVENS ROBERT , GOBLE CAROLE , ROBERTS ANGUS , GREENWOOD MARK
Published: March 2003

The growing quantity and distribution of bioinformatics resources means that finding and utilizing them requires a great deal of expert knowledge, especially as many resources need to be tied together into a workflow to accomplish a useful goal. We want to formally capture at least some of this knowledge within a virtual workbench and middleware framework to assist a wider range of biologists in utilizing these resources. Different activities require different representations of knowledge. Finding or substituting a service within a workflow is often best supported by a classification. Marshalling and configuring services is best accomplished using a formal description. Both representations are highly interdependent and maintaining consistency between the two by hand is difficult. We report on a description logic approach using the web ontology language DAML+OIL that uses property based service descriptions. The ontology is founded on DAML-S to dynamically create service classifications. These classifications are then used to support semantic service matching and discovery in a large grid based middleware project [Formula: see text]. We describe the extensions necessary to DAML-S in order to support bioinformatics service description; the utility of DAML+OIL in creating dynamic classifications based on formal descriptions; and the implementation of a DAML+OIL ontology service to support partial user-driven service matching and composition.
Electrical and Contractile Remodeling During the First Days of Atrial Fibrillation Go Hand in Hand
Authors: Schotten Ulrich , Duytschaever Mattias , Ausma Jannie , Eijsbouts Sabine , Neuberger Hans-Ruprecht , Allessie Maurits
Published: March 2003

Background—

The mechanisms of the atrial contractile dysfunction induced by atrial fibrillation (AF) are not completely understood. In particular, the relation between the atrial dysfunction and electrical remodeling has not yet been studied.

Methods and Results—

Seven goats were chronically instrumented with electrodes sutured to the atria and with ultrasonic piezoelectric crystals to record the atrial diameters. A pressure transducer was implanted in the right atrium. After 5 minutes, 3 hours, and throughout the first 5 days of artificially maintained AF, atrial contractile function was measured and the atrial effective refractory period (AERP) was monitored for comparison. Also, the positive inotropic effects of the L-type Ca
2+
-channel agonist BayY5959 and short trains of rapid atrial pacing were studied. After resumption of sinus rhythm, the recovery of atrial contractile function was followed. After 5 minutes of AF, atrial contractility was decreased by ≈55% but recovered completely within 10 minutes. Five days of AF nearly completely abolished the atrial contractile function, and recovery took 2 days. During the first days of AF, the development of the contractile dysfunction followed the same time course as the shortening of AERP (electrical remodeling). In remodeled atria, BayY5959 increased atrial contractility to the same extent as it prolonged AERP. The inotropic effect of short trains of rapid atrial pacing was similar in normal and remodeled atria.

Conclusions—

Depending on the duration of AF, different mechanisms contribute to the AF-induced atrial hypocontractility. Atrial contractile remodeling during several days of AF goes hand in hand with electrical remodeling and might be caused by a reduction of the L-type Ca
2+
-current.
Cardiac Benefits of Fish Consumption May Depend on the Type of Fish Meal Consumed
Authors: Mozaffarian Dariush , Lemaitre Rozenn N. , Kuller Lewis H. , Burke Gregory L. , Tracy Russell P. , Siscovick David S.
Published: March 2003

Background—

Few studies have examined associations of fish consumption with ischemic heart disease (IHD) risk among older adults or how different types of fish meals relate to IHD risk.

Methods and Results—

In a population-based prospective cohort study, usual fish consumption was ascertained at baseline among 3910 adults aged ≥65 years and free of known cardiovascular disease in 1989 and 1990. Consumption of tuna and other broiled or baked fish correlated with plasma phospholipid long-chain n-3 fatty acids, whereas consumption of fried fish or fish sandwiches (fish burgers) did not. Over 9.3 years’ mean follow-up, there were 247 IHD deaths (including 148 arrhythmic deaths) and 363 incident nonfatal myocardial infarctions (MIs). After adjustment for potential confounders, consumption of tuna or other broiled or baked fish was associated with lower risk of total IHD death (
P
for trend=0.001) and arrhythmic IHD death (
P
=0.001) but not nonfatal MI (
P
=0.44), with 49% lower risk of total IHD death and 58% lower risk of arrhythmic IHD death among persons consuming tuna/other fish 3 or more times per week compared with less than once per month. In similar analyses, fried fish/fish sandwich consumption was not associated with lower risk of total IHD death, arrhythmic IHD death, or nonfatal MI but rather with trends toward higher risk.

Conclusions—

Among adults aged ≥65 years, modest consumption of tuna or other broiled or baked fish, but not fried fish or fish sandwiches, is associated with lower risk of IHD death, especially arrhythmic IHD death. Cardiac benefits of fish consumption may vary depending on the type of fish meal consumed.
Relation Between Platelet Response to Exercise and Coronary Angiographic Findings in Patients With Effort Angina
Authors: Lanza Gaetano Antonio , Sestito Alfonso , Iacovella Sonia , Morlacchi Laura , Romagnoli Enrico , Schiavoni Giovanni , Crea Filippo , Maseri Attilio , Andreotti Felicita
Published: March 2003

Background—

Platelet reactivity is increased by exercise in patients with obstructive coronary artery disease (CAD) but not in patients with syndrome X. In this study, we prospectively investigated whether the platelet response to exercise might help distinguish, among patients with angina, those with obstructive CAD from those with normal coronary arteries (NCAs).

Methods and Results—

Venous blood samples were collected before and 5 minutes after exercise from 194 consecutive patients with stable angina. Platelet reactivity was measured by the platelet function analyzer (PFA)-100 system as the time for flowing whole blood to occlude a collagen-adenosine diphosphate ring (closure time). Coronary angiography showed CAD in 163 patients (84%) and NCA in 31 patients (16%). Baseline closure time was shorter in NCA patients (78.0±16 versus 95.5±23 seconds,
P
<0.0001). With exercise, closure time decreased in CAD patients (−15.5 seconds; 95% confidence limits [CL], −13.0 to −18.0 seconds;
P
<0.0001), but increased in NCA patients (12.5 seconds; 95% CL, 7.4 to 17.7 seconds;
P
=0.0004). An increase in closure time with exercise ≥10 seconds had 100% specificity and positive predictive value for NCAs. Similarly, a decrease ≥10 seconds had 100% specificity and positive predictive value for CAD. A closure time change (increase or decrease) ≥10 seconds allowed a correct classification of 55% of all patients.

Conclusions—

Among patients with stable angina, the response of platelet reactivity to exercise was predictive of normal or stenosed coronary arteries at angiography. Specifically, an increase in closure time with exercise ≥10 seconds was invariably associated with the presence of NCA.