bluuebunny/crossref_metadata_2025 huggingface dataset:
Using statistical image models for objective evaluation of spot detection in two‐dimensional gels
Authors: Rogers Mike , Graham Jim , Tonge Robert P.
Published: June 2003

Protein spot detection is central to the analysis of two‐dimensional electrophoresis gel images. There are many commercially available packages, each implementing a protein spot detection algorithm. Despite this, there have been relatively few studies comparing the performance characteristics of the different packages. This is in part due to the fact that different packages employ different sets of user‐adjustable parameters. It is also partly due to the fact that the images are complex. To carry out an evaluation, “ground truth” data specifying spot position, shape and intensities needs to be defined subjectively on selected test images. We address this problem by proposing a method of evaluation using synthetic images with unambiguous interpretation. The characteristics of the spots in the synthetic images are determined from statistical models of the shape, intensity, size, spread and location of real spot data. The distribution of parameters is described using a Gaussian mixture model obtained from training images. The synthetic images allow us to investigate the effects of individual image properties, such as signal‐to‐noise ratios and degree of spot overlap, by measuring quantifiable outcomes, e.g. accuracy of spot position, false positive and false negative detection. We illustrate the approach by carrying out quantitative evaluations of spot detection on a number of widely used analysis packages.
Mapping of proteins in human saliva using two‐dimensional gel electrophoresis and peptide mass fingerprinting
Authors: Ghafouri Bijar , Tagesson Christer , Lindahl Mats
Published: June 2003

Human saliva contains a large number of proteins that can be used for diagnosis and are of great potential in clinical and epidemiological research. The aim of this work was to map the proteins in saliva by two‐dimensional gel electrophoresis (2‐DE), and to identify abundant proteins by peptide mass fingerprinting using trypsin cleavage and matrix‐assisted laser desorption/ionization‐time of flight‐mass spectrometry analysis. One hundred proteins were identified representing 20 different identities according to accession numbers. Abundant proteins expressed in different forms were: α‐amylase, immunoglobulin A, prolactin‐inducible protein, zinc‐α2‐glycoprotein and cystatins (S, SA, D and SN). Other proteins found were interleukin‐1 receptor antagonist, von Ebner’s gland protein (lipocalin‐1) and calgranulin A and B (S100A8 and A9). Furthermore, apolipoprotein A‐I, β2‐microglobulin, glutathione S‐transferase P and fatty acid‐binding protein were also identified. Our results show that human saliva contains a large number of proteins that are involved in inflammatory and immune responses. The 2‐DE protein map constructed opens the possibility to investigate protein changes associated with disease processes.
Proteome analysis of aerobic and fermentative metabolism in Rhizobium etli CE3
Authors: Encarnación Sergio , Guzmán Yudith , Dunn Michael F. , Hernández Magdalena , Vargas Maria del Carmen , Mora Jaime
Published: June 2003

Rhizobium etli undergoes a transition from an aerobic to a fermentative metabolism during successive subcultures in minimal medium. This metabolic transition does not occur in cells subcultured in rich medium, or in minimal medium containing either biotin or thiamine. In this report, we characterize the aerobic and fermentative metabolism of R. etli using proteome analysis. According to their synthesis patterns in response to aerobic (rich medium, minimal medium with biotin or minimal medium with thiamine) or fermentative (minimal medium without supplements) growth conditions, proteins were assigned to five different classes: (i) proteins produced only in aerobic conditions (e.g., catalase‐peroxidase KatG and the E2 component of pyruvate dehydrogenase); (ii) protein produced under both conditions but strongly induced in aerobic metabolism (e.g., malate dehydrogenase and the succinyl‐CoA synthetase β subunit); (iii) proteins that were induced equally under all conditions tested (e.g., AniA, DnaK, and GroEL); (iv) proteins downregulated during aerobic metabolism, and (v) proteins specific to only one of the conditions analyzed. Northern blotting studies of katG expression confirmed the proteome data for this protein. The negative regulation of carbon metabolism proteins observed in fermentative metabolism is consistent with the drastic physiological changes which occur during this process.
Morphology, structure, and properties of in situ compatibilized linear low‐density polyethylene/polystyrene and linear low‐density polyethylene/high‐impact polystyrene blends
Authors: Gao Ying , Huang Honglian , Yao Zhanhai , Shi Dean , Ke Zhuo , Yin Jinghua
Published: June 2003

Blends of linear low‐density polyethylene (LLDPE) with polystyrene (PS) and blends of LLDPE with high‐impact polystyrene (HIPS) were prepared through a reactive extrusion method. For increased compatibility of the two blending components, a Lewis acid catalyst, aluminum chloride (AlCl3), was adopted to initiate the Friedel–Crafts alkylation reaction between the blending components. Spectra data from Raman spectra of the LLDPE/PS/AlCl3 blends extracted with tetrahydrofuran verified that LLDPE segments were grafted to the para position of the benzene rings of PS, and this confirmed the graft structure of the Friedel–Crafts reaction between the polyolefin and PS. Because the in situ generated LLDPE‐g‐PS and LLDPE‐g‐HIPS copolymers acted as compatibilizers in the relative blending systems, the mechanical properties of the LLDPE/PS and LLDPE/HIPS blending systems were greatly improved. For example, after compatibilization, the Izod impact strength of an LLDPE/PS blend (80/20 w/w) was increased from 88.5 to 401.6 J/m, and its elongation at break increased from 370 to 790%. For an LLDPE/HIPS (60/40 w/w) blend, its Charpy impact strength was increased from 284.2 to 495.8 kJ/m2. Scanning electron microscopy micrographs showed that the size of the domains decreased from 4–5 to less than 1 μm, depending on the content of added AlCl3. The crystallization behavior of the LLDPE/PS blend was investigated with differential scanning calorimetry. Fractionated crystallization phenomena were noticed because of the reduction in the size of the LLDPE droplets. The melt‐flow rate of the blending system depended on the competition of the grafting reaction of LLDPE with PS and the degradation of the blending components. The degradation of PS only happened during the alkylation reaction between LLDPE and PS. Gel permeation chromatography showed that the alkylation reaction increased the molecular weight of the blend polymer. The low molecular weight part disappeared with reactive blending. © 2003 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 41: 1837–1849, 2003
Attitudes, knowledge, risk perceptions and decision‐making among women with breast and/or ovarian cancer considering testing for BRCA1 and BRCA2 and their spouses
Authors: Bluman Leslie G. , Rimer Barbara K. , Sterba Katherine Regan , Lancaster Julia , Clark Shelly , Borstelmann Nancy , Iglehart J. Dirk , Winer Eric P.
Published: June 2003

A limited number of studies have examined the involvement of spouses in the decision‐making process for genetic testing as well as impact of the actual testing. This report presents data from 40 women with a personal history of breast and/or ovarian cancer who were considering genetic testing for BRCA1 and BRCA2 and their spouses. We examined knowledge and attitudes regarding genetic testing for breast cancer susceptibility, perceptions of the likelihood that their wives (the women) had a BRCA1 or BRCA2 mutation, pros and cons of genetic testing, spouses' satisfaction with their involvement in the decision‐making process and additional resources they would find helpful. Knowledge about cancer genetics and genetic testing for BRCA1 and BCA2 was limited among both women and their spouses. Up to one‐third of spouses indicated that they would like to avail themselves of additional sources of information about BRCA1 and BRCA2 testing. Most spouses indicated that they thought their wives had a mutation in BRCA1 or BRCA2 and that their wives' breast cancers would recur. Pros of genetic testing were emphasized more than cons among both parties. Overall, spouses were satisfied with their role in the decision‐making process. Future interventions to improve the decision‐making process regarding genetic testing for breast cancer susceptibility should be undertaken. Copyright © 2003 John Wiley & Sons, Ltd.
The role of religious coping in adjustment to cancer
Authors: Nairn Raymond C. , Merluzzi Thomas V.
Published: June 2003

This study tested a model of adjustment to cancer in which social support, disease impact, and religious coping were hypothesized to have an impact on adjustment to cancer that was mediated by self‐efficacy. Two hundred and ninety‐two people with cancer completed questionnaires. Three analyses were undertaken: first, the structure of the Religious Problem Solving Scale was assessed by a factor analysis in which two factors emerged, Deferring–Collaborative and Self‐Directing; second, the resulting factors' relationships to outcome measures were assessed through correlational and regression analyses; third, a mediated model of coping was tested with self‐efficacy as a mediating variable between religious coping and adjustment. The Deferring–Collaborative factor had positive relationships with most of the variables and was partially mediated by self‐efficacy. The results indicate that religious coping has no relationship to quality of life, a positive relationship with adjustment, and was more important in this study than available social support. Copyright © 2003 John Wiley & Sons, Ltd.
The quintic standard model
Authors: Körs B.
Published: June 2003

We consider brane world compactifications of type I string theory, where O‐planes and D‐branes are wrapped on supersymmetric cycles in Calabi‐Yau 3‐folds. General conditions for supersymmetric vacua are discussed and the concept of intersecting branes that break supersymmetry in a particular weak way is developed. It provides a setting in which one can very concretely engineer gauge groups and chiral fermion spectra according to the features of realistic low energy field theory models of particle interactions. For the example of the well known quintic Calabi‐Yau this is applied to produce a string compactification with Standard Model gauge group and three generation matter spectrum satisfying all string consistency requirements. We also add some comments on the status of anomaly cancellation via the Green‐Schwarz mechanism which is linked to the appearance of Stückelberg masses for abelian gauge bosons. Finally we demonstrate how the branes induce a scalar potential in the effective action via their tension, taking the form of an ${\cal N}=1$ D‐term.
Topological transitions and enhançon‐like geometries in Calabi‐Yau compactifications of M‐theory
Authors: Mohaupt T.
Published: June 2003

We study the impact of topological phase transitions of the internal Calabi‐Yau threefold on the space‐time geometry of five‐dimensional extremal black holes and black strings. For flop transitions and SU(2) gauge symmetry enhancement we show that solutions can always be continued and that the behaviour of metric, gauge fields and scalars can be characterized in a model independent way. Then we look at supersymmetric solutions which describe naked singularities rather than geometries with a horizon. For black strings we show that the solution cannot become singular as long as the scalar fields take values inside the Kähler cone. For black holes we establish the same result for the elliptic fibrations over the Hirzebruch surfaces ℱ0, ℱ1, ℱ2. These three models exhibit a behaviour similar to the enhançon, since one runs into SU(2) enhancement before reaching the apparent singularity. Using the proper continuation inside the enhançon radius one finds that the solution is regular.
COWPEA YIELD GAIN FROM RESISTANCE TO STRIGA GESNERIOIDES PARASITISM IN SOUTHERN BÉNIN
Authors: CARSKY R. J. , AKAKPO C. , SINGH B. B. , DETONGNON J.
Published: June 2003

Striga gesnerioides is a serious parasite of cowpea (Vigna unguiculata) on the Abomey plateau of southern Bénin. S. gesnerioides in southern Bénin has been characterized as a race that is different from those found in the dry savanna of West Africa. IITA breeding line IT93KZ-4-5-6-1-5 was used in a trial to study fertilizer response of cowpea on two farmers' fields in 1998. No emerged S. gesnerioides plants were observed on this breeding line while heavy parasite loads were observed on local cultivars growing in adjacent fields. In 1999, IT93KZ-4-5-6-1-5 was grown again on seven fields and no emerged S. gesnerioides plants were observed. In 2000 the same line was grown on 18 farmers' fields with local cowpea cultivars in adjacent control plots. The mean number of S. gesnerioides plants on the local cultivars was 0.92 per cowpea plant (s.d. 0.72) while the improved line carried none. The mean yield gain from the improved cowpea line was 156% and varied from 20 to 680 kg pods ha−1. Thus it appears that progress has been made in developing cowpea lines that are resistant to S. gesnerioides and the potential impact of adoption of resistant cowpea is high.
The influence of demography, population structure and selection on molecular diversity in the selfing freshwater snail Biomphalaria pfeifferi
Authors: ANGERS BERNARD , CHARBONNEL NATHALIE , GALTIER NICOLAS , JARNE PHILIPPE
Published: June 2003

Several forces may affect the distribution of genetic diversity in natural populations when compared to what is expected in a random-mating, constant size population of neutral genes. One solution for unravelling their respective influence is to study several genes at once in order to better reflect the true genealogy. Here we reconstruct the evolutionary history of the freshwater snail Biomphalaria pfeifferi over its entire distribution, using eight African populations, and three congeneric species as outgroups. A phylogenetic analysis was conducted using amplified fragment length polymorphism markers, and sequences at eight nuclear non-coding loci and one mitochondrial gene were used to analyse population structure. The geographic distribution of variation suggests greater affinities within than among regions. The pattern of variability at both the nuclear and mitochondrial DNA (mtDNA) loci is consistent with a bottleneck, although population structure may also partly explain our results. Our results are also indicative of the role of selection, whether positive or purifying, in the mtDNA. This highlights the fact that the interfering influences of population structure, demography and selection on molecular variation are not easily distinguished.
Phenological segregation of insecticide resistance alleles in the codling moth Cydia pomonella (Lepidoptera: Tortricidae): a case study of ecological divergences associated with adaptive changes in populations
Authors: BOIVIN THOMAS , BOUVIER JEAN-CHARLES , BESLAY DOMINIQUE , SAUPHANOR BENOIT
Published: June 2003

Intrapopulation variability in the seasonal regulation of insect lifecycles has been shown to be due partly to genetic changes. Selection for insecticide resistance in the codling moth Cydia pomonella results from allelic substitution at two to three loci in south-eastern French populations of this species. However, such an adaptive process has been associated with an increased heterogeneity in the developmental responses to climatic factors such as temperature. In this paper, we investigate whether such pleiotropic effects of resistance on development induce a significant discrepancy in seasonal regulation in this species. The seasonal changes in a susceptible and two insecticide-resistant homozygous genotypes of C. pomonella, as well as their reciprocal F1 progeny, were followed under natural conditions during the reproductive season through the emergence events of adults, within-generation developmental rates and the number of generations. A significant delay in the occurrences of homozygous resistant genotypes resulted from significantly lower pre-imaginal developmental times relative to homozygous susceptible ones. Subsequent assessment of the number of generations indicated significantly higher diapause propensities in carriers of the resistance alleles (37·0–76·2%) than in susceptible homozygotes (6·7%), which mostly pupated towards a third generation of adults. In the light of these findings, pleiotropic effects of adaptive changes might be a crucial source of divergence in seasonal regulation at the population level, involving significant life-history trade-offs. In addition to man-made selective factors during the reproductive season, such an effect on the lifecycle could be a key component in the process of selection for resistance genes in south-eastern France C. pomonella populations.
How labour organization may affect technology adoption: an analytical framework analysing the case of integrated pest management
Authors: Beckmann Volker , Wesseler Justus
Published: June 2003

Integrated Pest Management (IPM) is an important component of sustainable agriculture. Farmers who switch from a more capital-intensive pesticide-based pest management strategy to IPM have to substitute capital with labour. The adoption of IPM will therefore depend, among other things, on the opportunity costs of labour. A simple model analyses the trade-off between IPM and current farmers' best practice in developing countries. Modifications of the model include different forms of labour organization in pest management, such as owner operated and short- and long-term labour contracts. The implications are that agricultural policies, environmental policies, and labour market policies can go hand in hand. Unfortunately, this will be more likely at a higher level of original pesticide use and hence a higher level of environmental costs.
Citizens' actions for protecting the environment in developing countries: an economic analysis of the outcome with empirical cases from India
Authors: Santhakumar V.
Published: June 2003

This paper analyses the impact of citizens' actions for protecting the environment in the context of the institutional features of developing countries. The enforcement of environmental regulation is likely to be weak in developing countries, and thus their citizens are being compelled to sue the polluters or take direct actions that are costly to the polluter. The theoretical and empirical analysis, based on 25 cases of citizens' action from the Kerala State of India, show that their impact is influenced by the institutional deficiencies of the country. Such deficiencies include the delay in resolving conflicts through court interventions and the lower cost of taking actions of civil disobedience due to poor law and order enforcement. The analysis leads to the conclusion that citizens' actions may not be very effective in controlling pollution from existing factories, and may be effective in blocking the establishment of new factories. Both these outcomes, i.e., the continued pollution in existing factories, and zero-pollution (or non-establishment) of new factories/projects, cause social losses, in the former case for the citizens and in the latter for the polluter.
Properties of phagocyte NADPH oxidase p47-phox mutants with unmasked SH3 (Src homology 3) domains: full reconstitution of oxidase activity in a semi-recombinant cell-free system lacking arachidonic acid
Authors: PENG Guihong , HUANG Jin , BOYD Mellonie , KLEINBERG Michael E.
Published: June 2003

In an early step in the assembly of the phagocyte NADPH oxidase, p47-phox translocates from the cytosol to the membrane, mediated by engagement of the N-termini of two p47-phox Src homology 3 (SH3) domains with a proline-rich region (PRR) in the p22-phox subunit of cytochrome b558. In response to phagocyte activation, several serine residues in a C-terminal arginine/lysine-rich domain of p47-phox are phosphorylated, leading to changes in the conformation of p47-phox and exposure of its N-terminal SH3 domain that is normally masked by internal association with the arginine/lysine-rich domain. We report that triple alanine substitutions at Asp-217, Glu-218 and Glu-223 in a short sequence that links the tandem p47-phox SH3 domains unmasked the N-terminal SH3 domain, similar to the effects of aspartic acid substitutions at Ser-310 and Ser-328 in the arginine/lysine-rich region. Recombinant p47-phox proteins with mutations in either the linker region or the arginine/lysine-rich domain were active in the absence of arachidonic acid stimulation in a cell-free NADPH oxidase system consisting of recombinant p67-phox, Rac1–guanosine 5′-[γ-thio]triphosphate and neutrophil membranes. Supplementing neutrophil membranes with phosphoinositides or other negatively charged phospholipids markedly enhanced cell-free superoxide generation by these p47-phox mutants in the absence of arachidonic acid, to levels equivalent to those generated by wild-type p47-phox following arachidonic acid activation. This enhancement may be related to recruitment to the membrane of p47-phox mediated by a novel secondary phox homology (PX) domain binding site that broadly recognizes phospholipids. No specific enhancement by specific phosphorylated phosphatidylinositols was found to suggest a dominant role for the p47-phox primary PX domain binding site. Truncated p47-phox S310D S328D lacking the C-terminal PRR was inactive in the cell-free system without arachidonic acid, but was fully active with arachidonic acid. This suggests that activation of NADPH oxidase in an arachidonate-free cell-free system requires association of the p47-phox C-terminal PRR with the p67-phox C-terminal SH3 domain.
Analysis of zinc-fingers and homeoboxes (ZHX)-1-interacting proteins: molecular cloning and characterization of a member of the ZHX family, ZHX3
Authors: YAMADA Kazuya , KAWATA Hiroko , SHOU Zhangfei , HIRANO Satoko , MIZUTANI Tetsuya , YAZAWA Takashi , SEKIGUCHI Toshio , YOSHINO Miki , KAJITANI Takashi , MIYAMOTO Kaoru
Published: June 2003

Human zinc-fingers and homeoboxes (ZHX) 1, a transcriptional repressor, was originally cloned as an interacting protein with the activation domain of the A subunit of nuclear factor-Y (NF-YA). As the first step in investigating the mechanism by which ZHX1 acts as a transcriptional repressor, we conducted a search of ZHX1-interacting proteins using a yeast two-hybrid system. Nuclear proteins such as ZHX1, transcriptional co-factors and DNA-binding proteins, zyxin, androgen-induced aldose reductase and eleven-nineteen lysine-rich leukaemia gene, as well as some unknown proteins, were cloned. Molecular cloning and determination of the nucleotide sequence of the full-length cDNA encoding a novel protein revealed that it consists of 956 amino acid residues and contains two zinc-finger (Znf) motifs and five homeodomains (HDs) as well as ZHX1. We concluded that the protein forms the ZHX family with ZHX1 and denoted it ZHX3. ZHX3 not only dimerizes with both ZHX1 and ZHX3, but also interacts with the activation domain of the NF-YA. Further analysis revealed that ZHX3 is a ubiquitous transcriptional repressor that is localized in nuclei and functions as a dimer. Lastly, the dimerization domain, the interaction domain with NF-YA, and the repressor domain are mapped to a region including the HD1 region, and two nuclear localization signals are mapped to the N-terminal through Znf1 and the HD2 region, respectively.
Characterization of human phosphoserine aminotransferase involved in the phosphorylated pathway of l-serine biosynthesis
Authors: BAEK Joo Youn , JUN D. Youn , TAUB Dennis , KIM Young Ho
Published: June 2003

In the present study, we first report two forms of human phosphoserine aminotransferase (PSAT) cDNA (HsPSATα and HsPSATβ). HsPSATα has a predicted open reading frame comprising 324 amino acids, encoding a 35.2 kDa protein (PSATα), whereas HsPSATβ consists of an open reading frame comprising 370 amino acids that encodes a 40 kDa protein (PSATβ). PSATα is identical with PSATβ, except that it lacks 46 amino acids between Val290 and Ser337 of PSATβ, which is encoded by the entire exon 8 (138 bp). Both PSATα and PSATβ can functionally rescue the deletion mutation of the Saccharomyces cerevisiae counterpart. Reverse transcriptase–PCR analysis revealed that the expression of PSATβ mRNA was more dominant when compared with PSATα mRNA in all human cell lines tested. PSATβ was easily detected in proportion to the level of mRNA; however, PSATα was detected only in K562 and HepG2 cells as a very faint band. The relative enzyme activity of glutathione S-transferase (GST)–PSATβ expressed in Escherichia coli appeared to be 6.8 times higher than that of GST–PSATα. PSAT mRNA was expressed at high levels (approx. 2.2 kb) in the brain, liver, kidney and pancreas, and very weakly expressed in the thymus, prostate, testis and colon. In U937 cells, the levels of PSAT mRNA and protein appeared to be up-regulated to support proliferation. Accumulation of PSAT mRNA reached a maximum in the S-phase of Jurkat T-cells. These results demonstrate that although two isoforms of human PSAT can be produced by alternative splicing, PSATβ rather than PSATα is the physiologically functional enzyme required for the phosphorylated pathway, and indicate that the human PSAT gene is regulated depending on tissue specificity as well as cellular proliferation status with a maximum level expression in the S-phase.
Proteus mirabilis glutathione S-transferase B1-1 is involved in protective mechanisms against oxidative and chemical stresses
Authors: ALLOCATI Nerino , FAVALORO Bartolo , MASULLI Michele , ALEXEYEV Mikhail F. , DI ILIO Carmine
Published: June 2003

We investigated the effects of several xenobiotics, including antimicrobial agents and general stress factors such as starvation, heat and osmotic shock, on the modulation of expression of Proteus mirabilis glutathione S-transferase B1-1 (PmGST B1-1). The level of expression of PmGST B1-1 was established by both Western- and Northern-blot experiments. Our results show that several compounds can modulate expression of PmGST B1-1. The level of PmGST B1-1 increased when bacterial cells were exposed to a variety of stresses such as 1-chloro-2,4-dinitrobenzene, H2O2, fosfomycin or tetracycline. A knock-out gstB gene was also constructed using the suicide vector pKNOCKlox-Ap. Successful inactivation of the wild-type gene was confirmed by PCR, DNA sequence analysis and Western blotting. Under normal culture conditions, this mutant was viable and displayed no significant phenotypic differences compared with the wild-type. However, viability tests revealed that the null mutant was more sensitive to oxidative stress in the form of H2O2 and to several antimicrobial drugs when compared with the wild-type. These results suggest that PmGST B1-1 has an active role in the protection against oxidative stress generated by H2O2 and it appears to be involved in the detoxification of antimicrobial agents.
Inhibition of staurosporine-induced apoptosis of endothelial cells by activated protein C requires protease-activated receptor-1 and endothelial cell protein C receptor
Authors: MOSNIER Laurent O. , GRIFFIN John H.
Published: June 2003

In a model of staurosporine-induced apoptosis using EAhy926 endothelial cells, inhibition of apoptosis by activated protein C was dose-dependent and required the enzyme's active site, implicating activated protein C-mediated proteolysis. Consistent with this implication, both protease-activated receptor-1 (PAR-1) and endothelial cell protein C receptor (EPCR) were required for the anti-apoptotic effects of activated protein C.
Exogenous porcine somatotropin administered to neonatal pigs at high doses can alter lifetime fat but not lean tissue deposition
Authors: Dunshea Frank. R. , Suster Danny , Kerton Douglas J. , Leury Brian J.
Published: June 2003

The growth rate of the young pig is generally much less than its potential and may be constrained by endocrine status as well as nutrient intake. The aim of the present study was to determine whether porcine (p) somatotropin (ST) treatment of the sucking pig could alter subsequent body composition. Twelve mixed-parity cross-bred sows with an average litter size of ten piglets were used to nurse pigs for the present study. On day 1 of lactation, the median two male pigs (by weight) from each litter were randomly allocated to one of two doses of pST (0 or 1 mg/kg per d) until weaning on day 21. Pigs were weaned and offered feed ad libitum until slaughter at 134 d of age. Body composition was measured using dual-energy X-ray absorptiometry (DXA) at 21, 49, 77, 105 and 133 d of age. There was no significant difference in growth rates between day 1 and 21 of lactation in pigs injected with either saline (9 g/l NaCl/l) or pST (258 v. 246 g/d for control and pST-treated pigs respectively, P=0·61), and as a consequence there was no significant difference in liveweight at weaning (7·13 v. 6·84 kg, P=0·59). However, fat mass at weaning tended to be decreased (1·18 v. 0·96 kg, P=0·064), while the % fat in the body at weaning was significantly (16·7 v. 13·9 %, P=0·008) decreased by exogenous pST treatment. In the immediate post-weaning period there was a reduction in lean tissue deposition (347 v. 300 g/d, P=0·021) but no effect on fat deposition (35 v. 33 g/d, P=0·72). Over the entire weaning-to-slaughter period, pST treatment of neonatal pigs decreased the rate of fat deposition (130 v. 112 g/d, P=0·033), but had no effect on lean tissue deposition (550 v. 538 g/d, P=0·49). Therefore, treatment of nursing pigs with high doses of pST for a short period before weaning may provide a means of reducing the fat content of pork and pork products.
The effect of oestrogen and dietary phyto-oestrogens on transepithelial calcium transport in human intestinal-like Caco-2 cells
Authors: Cotter Alice A. , Jewell Christopher , Cashman Kevin D.
Published: June 2003

Recently, dietary phyto-oestrogens (PO) have been suggested as possible alternatives to oestrogen therapy (hormone replacement therapy) as a means of preventing bone loss associated with ovarian hormone deficiency. While PO, which exhibit oestrogen-like activity, act directly on bone cells, their protective effect on bone may be partly due to their ability to enhance Ca absorption. Therefore, the aim of the present study was to investigate the effect of 17β-oestradiol and two commonly consumed soyabean PO (genistein and daidzein) on Ca absorption in the human Caco-2 intestinal-like cell model. Caco-2 cells were seeded onto permeable filter supports and allowed to differentiate into monolayers. On day 21, the Caco-2 monolayers (n8–18 per treatment), grown in oestrogen-replete or -deplete media, were then exposed to 10 nM-17β-oestradiol, 1 nM-1,25-dihydroxycholecalciferol, or 50 μM-genistein or -daidzein for 24 h. After exposure, transepithelial and transcellular transport of45Ca and fluorescein transport (a marker of paracellular diffusion) were measured. As expected, 1,25-dihydroxycholecalciferol stimulated Ca absorption in Caco-2 cells, by up-regulating transcellular transport, whereas 17β-oestradiol had no effect on Ca absorption. Unexpectedly, both PO decreased Ca absorption (by about 17–19 % compared with control,P<0·05), by reducing transcellular Ca transport in Caco-2 cells grown in oestrogen-replete media. This inhibitory effect disappeared when monolayers were grown in oestrogen-deplete media. In conclusion, PO at high luminal concentrations either had no effect or reduced Ca absorption in Caco-2 cells, dependent on oestrogen status. The effect of lower concentrations of these compounds needs to be investigated.
Translation of Polarity Cues into Asymmetric Spindle Positioning in
Caenorhabditis elegans
Embryos
Authors: Colombo Kelly , Grill Stephan W. , Kimple Randall J. , Willard Francis S. , Siderovski David P. , Gönczy Pierre
Published: June 2003

Asymmetric divisions are crucial for generating cell diversity; they rely on coupling between polarity cues and spindle positioning, but how this coupling is achieved is poorly understood. In one-cell stage
Caenorhabditis elegans
embryos, polarity cues set by the PAR proteins mediate asymmetric spindle positioning by governing an imbalance of net pulling forces acting on spindle poles. We found that the GoLoco-containing proteins GPR-1 and GPR-2, as well as the Gα subunits GOA-1 and GPA-16, were essential for generation of proper pulling forces. GPR-1/2 interacted with guanosine diphosphate-bound GOA-1 and were enriched on the posterior cortex in a
par-3
– and
par-2–
dependent manner. Thus, the extent of net pulling forces may depend on cortical Gα activity, which is regulated by anterior-posterior polarity cues through GPR-1/2.
LINEAR TIME RECOGNITION AND OPTIMIZATIONS FOR WEAK-BISPLIT GRAPHS, BI-COGRAPHS AND BIPARTITE P6-FREE GRAPHS
Authors: GIAKOUMAKIS V. , VANHERPE J. M.
Published: June 2003

In [7] was introduced a new decomposition scheme for bipartite graphs that was called canonical decomposition. Weak-bisplit graphs are totally decomposable following this decomposition. We give here linear time algorithms for the recognition of weak-bisplit graphs as well as for two subclasses of this class, the P6-free bipartite graphs and the bi-cographs. Our algorithms extends the technics developped in [2] for cographs's recognition. We conclude by presenting efficient solutions for some optimization problems when dealing with weak-bisplit graphs.
STRUCTURAL PROPERTIES OF DIAMOND NANORODS: MOLECULAR-DYNAMICS SIMULATIONS
Authors: MALCIOĞLU OSMAN BARIŞ , ERKOÇ ŞAKIR
Published: June 2003

The structural properties of carbon nanorods obtained from diamond crystal have been investigated by performing molecular-dynamics computer simulations. Calculations have been realized by using an empirical many-body potential energy function for carbon. Diamond nanorods have been generated from three low-index planes of diamond crystal. It has been found that the average coordination number, cross-section geometry, and surface orientation from which the nanorod is generated play a role in the stability of diamond nanorods under heat treatment. The most stable diamond nanorod has been obtained from the (111) surface.
GENERALIZED RICCATI EQUATION EXPANSION METHOD AND ITS APPLICATION TO THE (2+1)-DIMENSIONAL BOUSSINESQ EQUATION
Authors: CHEN YONG , LI BIAO , ZHANG HONGQING
Published: June 2003

Based on the computerized symbolic system Maple and a Riccati equation, a new Riccati equation expansion method for constructing nontraveling wave and coefficient functions' soliton-like solutions is presented by a new general ansätz. The proposed method is more powerful than most of the existing tanh methods, the extended tanh-function method, the modified extended tanh-function method, and generalized hyperbolic-function method. By using the method, we not only successfully recovered the previously known formal solutions but could also construct new and more general formal solutions for some nonlinear differential equations. Making use of the method, we study the (2+1)-dimensional Boussinesq equation and obtain rich new families of the exact solutions, including the nontraveling wave and coefficient functions' soliton-like solutions, singular soliton-like solutions, and triangular functions solutions.
MULTIFRACTAL CHARACTERISTICS OF LINEAR ONE-DIMENSIONAL CELLULAR AUTOMATA
Authors: SANCHEZ JUAN R.
Published: June 2003

Cellular automata (CA) can be considered as discrete dynamical systems exhibiting a rich intrinsic behavior both in space and time. Starting from disordered initial configurations and according to different local evolution rules, CA can evolve into steady states showing regular or complex space–time structures. These structures have been shown to have fractal and multifractal properties. Here, the multifractal properties of linear one-dimensional cellular automata with complex spatio-temporal behaviors are calculated using discrete wavelets transforms.
QUANTUM ASSOCIATIVE MEMORY
Authors: ANDRECUT M. , ALI M. K.
Published: June 2003

The unique characteristic of quantum mechanics may be used in the near future to create a quantum associative memory with a capacity exponential in the number of neurons. In this paper we discuss some quantum computational ideas and algorithms necessary to develop a quantum associative memory.
COHERENT STATES OF NONCONSERVATIVE HARMONIC OSCILLATOR WITH A SINGULAR PERTURBATION
Authors: CHOI JEONG RYEOL
Published: June 2003

We investigated the coherent states of nonconservative harmonic oscillator with a singular perturbation. The invariant operator represented in terms of lowering and raising operators. We confirmed that if the difference between two eigenvalues, α and β, of coherent states is much larger than unity, the states |α> and |β> are approximately orthogonal to each another. We calculated the expectation values of various quantities such as invariant operator, Hamiltonian and mechanical energy in coherent state. The mechanical energy of the system described by the Kanai–Caldirola Hamiltonian decreased exponentially depending on γ as time goes by in coherent state.
ON SPATIAL LYAPUNOV EXPONENTS AND SPATIAL CHAOS
Authors: LIU SHU TANG , CHEN GUANRONG
Published: June 2003

In this paper, we investigate the periodic orbits, spatial Lyapunov exponents, and stability of spatially periodic orbits of the general 2D Logistic system [Formula: see text] where a is a real constant and μ is a parameter. The existence of spatial chaos in the sense of Li and Yorke is proved using the Marotto theorem. These results extend the corresponding results in the 1D Logistic system [Formula: see text] where n0is a fixed integer. These results also improve some existing results of the 2D coupled map lattice (CML) model [Formula: see text] where ε > 0 is the coupling constant.
BIFURCATIONS IN A HUMAN MIGRATION MODEL OF SCHEURLE–SEYDEL TYPE-I: TURING BIFURCATION
Authors: KOVÁCS SÁNDOR
Published: June 2003

In this paper we consider a model for the behavior of students in graduate programs at neighboring universities which is a modified form of the model proposed by [Scheurle & Seydel, 2000], and observe that the stationary solution of this two-component system becomes unstable in the presence of diffusion. We assume that both types of individuals are continuously distributed throughout a bounded two-dimensional spatial domain of two types (regular hexagon and rhombus), across whose boundaries there is no migration, and which simultaneously undergo simple (Fickian) diffusion but the spatial flow is influenced not only by its own but also by the other's density (cross diffusion). We will show that at a critical value of a parameter a Turing bifurcation takes place: a spatially nonhomogenous solution (pattern) arises.
NAKED SINGULARITIES IN THREE-DIMENSIONS
Authors: OLIVEIRA-NETO G.
Published: June 2003

We study an analytical solution to the Einstein's equations in (2+1)-dimensions, representing the self-similar collapse of a circularly symmetric, minimally coupled, massless, scalar field. Depending on the value of certain parameters, this solution represents the formation of naked singularities. Since our solution is asymptotically flat, these naked singularities may be relevant for the weak cosmic censorship conjecture in (2+1)-dimensions.
INVARIANT DEFINITION OF REST MASS AND DYNAMICS OF PARTICLES IN 4D FROM BULK GEODESICS IN BRANE-WORLD AND NON-COMPACT KALUZA–KLEIN THEORIES
Authors: PONCE DE LEON J.
Published: June 2003

In the Randall–Sundrum brane-world scenario and other non-compact Kaluza–Klein theories, the motion of test particles is higher-dimensional in nature. In other words, all test particles travel on five-dimensional geodesics but observers, who are bounded to spacetime, have access only to the 4D part of the trajectory. Conventionally, the dynamics of test particles as observed in 4D is discussed on the basis of the splitting of the geodesic equation in 5D. However, this procedure is not unique and therefore leads to some problems. The most serious one is the ambiguity in the definition of rest mass in 4D, which is crucial for the discussion of the dynamics. We propose the Hamilton–Jacobi formalism, instead of the geodesic one, to study the dynamics in 4D. On the basis of this formalism we provide an unambiguous expression for the rest mass and its variation along the motion as observed in 4D. It is independent of the coordinates and any parameterization used along the motion. Moreover, we are able to show a comprehensive picture of the various physical scenarios allowed in 4D, without having to deal with the subtle details of the splitting formalism. Moreover we study the extra non-gravitational forces perceived by an observer in 4D who describes the geodesic motion of a bulk test particle in 5D. Firstly, we show that the so-called fifth force fails to account for the variation of rest mass along the particle's worldline. Secondly, we offer here a new definition that correctly takes into account the change of mass observed in 4D.
ANALYSIS AND NUMERICAL COMPUTATION OF THE DIMENSION OF COLORED NOISE AND DETERMINISTIC TIME SERIES WITH POWER-LAW SPECTRA
Authors: ZHANG WEN , WEST BRUCE J.
Published: June 2003

We investigate the box dimension of a graph of time series generated by trigonometric series with an inverse power-law spectrum. Such time series can either be random, in which case it is called colored noise, or deterministic in nature. We show analytically that both series can have fractal dimensions depending on the value of the exponent in the power-law. However, the fractal dimension of colored noise is 0.5 higher than that of the corresponding deterministic series. We comment on calculating fractal dimensions and present a reliable numerical algorithm which yields a high degree of consistency between experimental and analytical results.
GAUSSIANS EVERYWHERE
Authors: PUENTE CARLOS E. , KLEBANOFF AARON D.
Published: June 2003

We use deterministic fractal functions, constructed as attractors of affine mappings in three dimensions, to transform multinomial multifractal and uniform measures to obtain a variety of two-dimensional distributions. When the graph of the fractal function is nearly space-filling, the derived two-dimensional distribution always approaches a bivariate Gaussian. This general result holds whenever the parent distribution is replaced by arbitrary measures which have continuous distributions. We give conditions on the fractal interpolating functions for which the coefficient of correlation is either zero or not. In a special case, the Gaussian’s correlation coefficient is shown to reflect the geometrical similitude between two nearly planefilling deterministic fractal curves.
OBSERVATION OF SPACE FILLING IN Celosia cristata FRACTAL
Authors: SEMKOW T. M. , HARRIS P. R. , SCHWENKER C. D. , SEMKOW A. G. , MILLER N. G.
Published: June 2003

The fasciate flower aggregates (inflorescences) of Celosia cristata (Amaranthaceae) exhibit fractal behavior in the range from ~2 to ~21 cm and have a surface fractal dimension ~3 in 3-dimensional embedding Euclidean space. The inflorescence of this plant thus provides an outstanding example of the space-filling concept that originated from Peano in 1890. Such a structure of Celosia cristata may be advantageous in wind pollination.
LONG-RANGE FRACTAL CORRELATIONS IN DNA INTRONS AND EXONS
Authors: VOSS RICHARD F.
Published: June 2003

Spectral density and random walk methods of analyzing symbolic sequences, such as DNA bases, are compared. Systematic errors in DNA walk analysis, wide variability between samples, and small ensembles cast doubt on previous conclusion that long-range correlations in DNA occur in non-coding (intron) sequences. A new study of all GenBank release 73 annotated features demonstrates that both introns and exons have similar long-range fractal correlations with exponents consistent with previous category averages.
EVOLUTIONARY DESIGN OF GENETIC CIRCUITS AND CELL-CELL COMMUNICATIONS
Authors: YOKOBAYASHI YOHEI , COLLINS CYNTHIA H. , LEADBETTER JARED R. , ARNOLD FRANCES H. , WEISS RON
Published: June 2003

Synthetic genetic circuits are artificial networks of transcriptional control elements inserted into living cells in order to 'program' cellular behavior. We can extend this application to programming population behavior by incorporating cell-cell communications capabilities. By designing and building such networks, cellular circuit engineers expect to gain insight into how natural genetic networks function with remarkable robustness, stability, and adaptability to changing environments. Programmed cells also have promising applications in biotechnology and medicine. A major challenge that biological circuit engineers face is the difficulty of predicting circuit performance at the design stage, with the consequence that actual construction requires significant experimental effort, even for very simple circuits. To address this fundamental obstacle we propose the use of laboratory evolution methods to create new circuit components and optimize circuit performance inside living cells.
Domestic Violence and Housing Problems
Authors: Baker Charlene K. , Cook Sarah L. , Norris Fran H.
Published: June 2003

This study examined housing problems and homelessness after separation in a sample of 110 women who had experienced domestic violence. Of the sample, 38% reported homelessness. Similar percentages reported housing problems (e.g., late paying rent, skipping meals, threatened with eviction). Predictors of more housing problems included experiencing a greater severity of violence, contacting fewer formal systems, having less informational support, and receiving a negative response from welfare. Women's odds of reporting homelessness were reduced by 30% if police officers responded positively. These findings highlight the importance of changing system responses in an effort to reduce women's housing problems and risks for homelessness after separation.
Architectural Support for Long Integer Modulo Arithmetic on Risc-Based Smart Cards
Authors: Großschädl Johann
Published: June 2003

Various algorithms for public-key cryptography, such as the Rivest-Shamir-Adleman or Diffie-Hellman algorithms, are based on long integer arithmetic operations, most notably modulo multiplication. To be adequate for long-term security, the modulus should have a length of at least 1024 bits. Long integer arithmetic is difficult to implement efficiently in software, particularly on smart cards due to their constrained resources and relatively slow clock frequency. In this paper we investigate the potential of application-specific instruction set extensions for cryptographic workloads such as long integer arithmetic. We define two special instructions that carry out computations of the form a ×b + c + d, whereby a,b,c,d are single-precision words (unsigned integers). These additional instructions can be executed on an optimized multiply/accumulate unit and therefore they are simple to incorporate into common RISC architectures such as the MIPS32. The proposed extensions cause almost no speed or area penalty since no extra functional units are required. Experimental results indicate that the inner-loop operation of a multiple-precision multiplication can be accelerated by a factor of almost 2. We also estimate the execution time of a 1024-bit modulo exponentiation assuming that these special instructions were made available. The presented concept is an alternative solution to a crypto co-processor, especially for multi-application smart cards (e.g. Java cards) with an embedded 32-bit RISC core.