bluuebunny/crossref_metadata_2025 huggingface dataset:
Transgenic maize in the presence of ampicillin modifies the metabolic profile and microbial population structure of bovine rumen fluidin vitro
Authors: Koch Melanie , Strobel Egbert , Tebbe Christoph C. , Heritage John , Breves Gerhard , Huber Korinna
Published: February 2008

Recently, transgenic crops have been considered as possible donors of transgenes that could be taken up by micro-organisms under appropriate conditions. In anin vitrorumen simulation system, effects of ampicillin on microbial communities growing either on rumen contents with transgenic maize carrying a gene that confers resistance to ampicillin or its isogenic counterpart as substrates were examined continuously over 13 d. Rate of production of SCFA was measured to determine functional changes in the rumen model and single-strand conformational polymorphism was used to detect alterations in structure of the microbial community. Rumen contents treated with ampicillin displayed a marked decrease in the rate of production of SCFA and diversity of the microbial community was reduced severely. In the presence of transgenic maize, however, the patterns of change of rumen micro-organisms and their metabolic profiles were different from that of rumen fluid incorporating maize bred conventionally. Recovery of propionate production was observed both in the rumen fluid fed transgenic and conventional maize after a delay of several days but recovery occurred earlier in fermenters fed transgenic maize. Alterations in the microbial population structures resulting from the ampicillin challenge were not reversed during the experimental run although there was evidence of adaptation of the microbial communities over time in the presence of the antibiotic, showing that populations with different microbial structures could resume a pre-challenge metabolic profile following the introduction of ampicillin, irrespective of the source of the plant material in the growth medium.
Functional markers of selenium status: UK Food Standards Agency workshop report
Authors: Elsom Rachel , Sanderson Peter , Hesketh John E. , Jackson Malcolm J. , Fairweather-Tait Susan J. , Åkesson Björn , Handy Jean , Arthur John R.
Published: February 2008

The workshop was organised to discuss the validity and limitations of existing functional markers of Se status in human subjects and to identify future research priorities in this area. Studies presented as part of this workshop investigated: the bioavailability of Se from different dietary sources; potential functional markers of Se status; individual variation in response to Se; the effect of marginal Se status on immune function. The workshop highlighted the need to define the relationship between functional markers of Se status and health outcomes.
Iron bioavailability: UK Food Standards Agency workshop report
Authors: Singh Mamta , Sanderson Peter , Hurrell Richard F. , Fairweather-Tait Susan J. , Geissler Catherine , Prentice Ann , Beard John L.
Published: February 2008

The UK Food Standards Agency convened a group of expert scientists to review current research investigating factors affecting iron status and the bioavailability of dietary iron. Results presented at the workshop show menstrual blood loss to be the major determinant of body iron stores in premenopausal women. In the presence of abundant and varied food supplies, the health consequences of lower iron bioavailability are unclear and require further investigation.
Wheat-fibre-induced changes of postprandial peptide YY and ghrelin responses are not associated with acute alterations of satiety
Authors: Weickert Martin O. , Spranger Joachim , Holst Jens J. , Otto Bärbel , Koebnick Corinna , Möhlig Matthias , Pfeiffer Andreas F. H.
Published: February 2008

Weight gain and risk of type 2 diabetes are inversely associated with a high intake of insoluble cereal fibres. Because nutrient-induced changes of ‘satiety hormones’ from the gut may play a role in this process, we evaluated the effects of purified insoluble fibres on postprandial responses of plasma peptide YY (PYY), serum ghrelin and satiety as secondary outcome measures of a study investigating effects of cereal fibres on parameters of glucose metabolism. Fourteen healthy women were studied on six occasions in a randomized, single-blind, controlled crossover design. After 24 h run-in periods and 10 h overnight fasts, subjects ingested isoenergetic and macronutrient matched portions of control white bread or fibre-enriched bread (wheat-fibre or oat-fibre) at 08.15 hours. Gut hormones and hunger scores were measured for 300 min. Basal PYY and ghrelin concentrations were not different between the test meals (P>0·15). Postprandial responses of PYY and ghrelin were blunted after the intake of wheat-fibre (total area under the curve (AUC) PYY, 177·9 (sem 8·1) (pmol/l) min; P=0·016; ghrelin 51·0 (sem 2·5) (pmol/l) min; P=0·003), but not after oat-fibre (PYY 226·7 (sem 25·7) (pmol/l) min; P>0·15; ghrelin 46·2 (sem 1·6) (pmol/l) min; P=0·127), compared to control (PYY 247·5 (sem 25·6) (pmol/l) min; ghrelin 42·5 (sem 1·3) (pmol/l) min). Postprandial hunger scores were unaffected by the different test meals (P>0·15). Thus, oat- and wheat-fibre consumption result in different postprandial responses of PYY and ghrelin, but interestingly do not differ in satiety effects.
Vegetable oils affect the composition of lipoproteins in sea bream (Sparus aurata)
Authors: Caballero Maria José , Torstensen Bente E. , Robaina Lidia , Montero Daniel , Izquierdo Marisol
Published: February 2008

The aim of the present study was to determine the influence of the dietary fatty acid profile on the lipoprotein composition in sea bream fed different vegetable oils. Six experimental diets were formulated combining fish oil with three vegetable oils (soybean, rapeseed, linseed) in order to obtain 60–80 % (w/w) fish-oil replacement. VLDL, LDL and HDL in plasma samples were obtained by sequential centrifugal flotation. The lipid class, protein content and fatty acid composition of each lipoprotein fraction were analysed. HDL was the predominant lipoprotein in sea bream plasma containing the highest proportion of protein (34 %) and phosphatidylcholine. LDL presented a high content of cholesterol, whereas triacylglycerol comprised a larger proportion of VLDL. The lipid class of the lipoprotein fractions was affected by the dietary vegetable oils. Thus, a high dietary inclusion of soyabean and linseed oil (80 %) increased the cholesterol in HDL and LDL in comparison to fish oil. Similarly, the triacylglycerol concentration of VLDL was increased in fish fed 80 % soyabean and linseed oils owing to the lown-3 highly unsaturated fatty acid content of these diets. Lipoprotein fatty acid composition easily responded to dietary fatty acid composition. VLDL was the fraction more affected by dietary fatty acid, followed by LDL and HDL. Then-3 highly unsaturated fatty acid content increased in the order VLDL less than LDL and less than HDL, regardless of dietary vegetable oils.
Conjugated linoleic acid, unlike other unsaturated fatty acids, strongly induces glutathione synthesis without any lipoperoxidation
Authors: Arab Khelifa , Rossary Adrien , Soulère Laurent , Steghens Jean-Paul
Published: February 2008

Enhancement of the redox status of cells is a cytoprotective strategy against oxidative damage. We recently showed that DHA upregulates glutathione (GSH) content via an induction of its related enzymes γ-glutamylcysteine ligase and glutathione reductase. In the present study, we investigated the effects of eight other fatty acids on the redox status and lipid peroxidation of human fibroblasts. After 48 h, only arachidonic acid and conjugated linoleic acid (CLA) enhanced GSH content through an induction of γ-glutamylcysteine ligase. CLA was more potent than arachidonic acid in inducing GSH synthesis. For all the fatty acids tested, lipoperoxidation, estimated by cell malondialdehyde measurement, did not differ from that of controls at 48 h but dramatically increased at 7 d, except for CLA. Lipoperoxidation is associated at 7 d with a high level of reactive oxygen species and with increased haemoxygenase-1 and cyclooxygenase-2 mRNA expression. As demonstrated by a tert-butylhydroperoxide cytotoxicity test, the GSH synthesis obtained with arachidonic acid is not sufficient to protect the cells, whereas this protective effect was obvious with CLA at 48 h as well as at 7 d. The present results show that CLA is the only PUFA able to induce GSH synthesis without any change in oxidative balance, whereas an upregulation of cyclooxygenase-2 by other PUFA is concomitant with an overproduction of malondialdehyde and reactive oxygen species. The particular hairpin conformation obtained for CLA by molecular modelling could account for this specific biological effect.
The effects of inulin supplementation of diets with or without hydrolysed protein sources on digestibility, faecal characteristics, haematology and immunoglobulins in dogs
Authors: Verlinden A. , Hesta M. , Hermans J. M. , Janssens G. P. J.
Published: February 2008

Dogs with food allergy are often treated by giving a diet with hydrolysed protein sources. Prebiotics might also be successful in prevention and treatment of allergic disease through their effect on the colonic microflora, analogous to studies on probiotics in allergic children. The present study was set up to investigate the effect of supplementing inulin (IN) to commercial hypoallergenic dog diets on apparent nutrient digestibility, faecal characteristics, haematology and Ig in dogs. Supplementation of 3 % IN did not affect faecal pH, food and water intake and urine production. Compared with the intact protein diet with a limited number of ingredients (L), the diet with a hydrolysed protein source (H) resulted in an increased water intake (P<0·001), which could be due to the osmotic effect of free amino acids. Faeces production was increased by IN due to increased faecal moisture content. Increased faeces production on the H diet was mainly due to a higher DM excretion. Subsequently, the apparent digestibility coefficient (ADC) of DM was lower in the H diet group. A similar result was noted for ADC of diethyl ether extract and crude ash. The ADC of crude protein was higher in the H diet group, whereas IN decreased the ADC of crude protein. Differences in the ADC of crude protein among the different diets disappeared after correction for a higher faecal biomass, except for the dogs fed the L + IN diet. Total faecal IgA concentrations were lower in the H group (P<0·05) because of lower antigenic stimulation of hydrolysed protein, which implies that hydrolysed protein is really hypoallergenic. The present study indicates that the use of hydrolysed protein diets for canine food allergy treatment can affect digestibility and that combination with IN affected apparent protein digestibility but not IgA response.
Measuring glycaemic responses: duplicate fasting samples or duplicate measures of one fasting sample?
Authors: Wolever Thomas M. S. , Ip Blanche , Moghaddam Elham
Published: February 2008

The precision with which glycaemic responses, expressed as incremental area under the curve (AUC), can be measured may be improved by using the average of several measures of fasting blood glucose (FBG). To see if taking two fasting blood samples would increase the precision of AUC, the glycaemic responses elicited by four test meals (50 g glucose; 50 g glucose plus 10 g fat and 10 g protein; 100 g white bread; 100 g white bread plus 10 g fat and 10 g protein) were determined in thirteen overnight-fasted healthy subjects. Two fasting blood samples were taken 5 min apart (−5 min and 0 min before starting to eat) with glucose measured three times in each sample. AUC was calculated using different estimates of FBG derived from the three measures of glucose in the two fasting blood samples and each set of AUC values subjected to ANOVA. Unexpectedly, the results were more precise when AUC was calculated from mean glucose in the 0 min blood sample (FBG0) than from mean glucose in the two different fasting blood samples. The 95 % CI of the AUC calculated using FBG0 in thirteen subjects was ±29·8; to obtain the same CI using the mean of the two fasting blood samples would require fourteen subjects. These results suggest that taking two fasting blood samples does not necessarily improve, and may even reduce, the precision of AUC as a measure of glycaemic response. Further studies are needed before requiring that two fasting blood samples be taken for determining glycaemic index.
Quantitative analysis of nitrate and nitrite contents in vegetables commonly consumed in Delta State, Nigeria
Authors: Onyesom I. , Okoh P. N.
Published: February 2008

Plasma thiocyanate has been reported to be high among cassava-eating populations such as that in Nigeria because of the cyanide content of cassava. Thiocyanate, which is secreted into the stomach contents of animals, has been demonstrated to catalyse the formation of nitrosamines (potent carcinogens) in the stomach from secondary amines and nitrite. The main source of the nitrite precursor in this environment is vegetables, primarily eaten as the chief supplier of proteins. The present study attempts to analyse the levels of nitrate and nitrite in vegetables commonly grown and consumed in Delta State, Nigeria. The nitrate and nitrite contents in green vegetable (Amaranthus spp.), bitter leaf (Vernonia amygdalina), pumpkin (Telfaria occidentalis) and water leaf (Talinum triangulare) grown in different localities of the state were determined by standard analytical procedures. The results show that those vegetables grown in the industrialised urban centres of the state had higher nitrate (223 (sd 71) mg/kg dry weight; P<0·05) and nitrite (12·6 (sd 1·7) mg/kg dry weight; P>0·05) levels when compared with the same species (188 (sd 77) mg nitrate/kg dry weight and 10·9 (sd 1·1) mg nitrite/kg dry weight) cultivated in less industrialised suburbs. We conclude that frequent consumption of such vegetables whose nitrate and nitrite contents are high by cassava-eating individuals might put them at risk of developing stomach cancer and other possible results of nitrate and/or nitrite toxicity. In order to avoid an outbreak in our communities, appropriate agencies should monitor and regulate the release of chemicals into the environment. In the meantime, the cultivation and consumption of vegetables grown in industrialised areas of the state should be discouraged.
Dietary intake and use of dietary supplements in relation to demographic variables among pregnant Finnish women
Authors: Arkkola Tuula , Uusitalo Ulla , Pietikäinen Minna , Metsälä Johanna , Kronberg-Kippilä Carina , Erkkola Maijaliisa , Veijola Riitta , Knip Mikael , Virtanen Suvi M. , Ovaskainen Marja-Leena
Published: February 2008

Proper nutrition during pregnancy may be important for maternal health and fetal growth and development. In Finland, targeted recommendations are given to guide pregnant women in their food choice and dietary supplement use so that they may obtain adequate nutritional status and meet the increased need for nutrients. The aims of the present study were to examine food choices, nutrient intake and dietary supplement use of pregnant Finnish women in association with demographic variables. One thousand and seventy-five families were invited to a birth cohort study during 1998–9. Mothers of 797 newborns completed a validated 181-item food-frequency questionnaire from which the food and nutrient intakes were calculated. The information about supplement use was collected concerning the whole pregnancy. The results of the present study suggest that healthy food choices are rather common among pregnant Finnish women and the choices are positively correlated with age and education. Nutrient supplements were used by 85 % of the women. Supplements were favoured by the older and well-educated women and by those who had normal weight before pregnancy. Of the women in the present study, 31 % received vitamin A-containing supplements, although it is not recommended during pregnancy. Taking food and supplementation into account, the intake of vitamin D did not meet the dietary recommendation and folic acid intake was below recommendation in 44 % of the women. Therefore there seemed to be unnecessary nutrient supplementation and at the same time lack of relevant supplementation among these pregnant women.
Development and cross-validation of prediction equations for estimating resting energy expenditure in severely obese Caucasian children and adolescents
Authors: Lazzer Stefano , Agosti Fiorenza , De Col Alessandra , Sartorio Alessandro
Published: February 2008

The objectives of the present study were to develop and cross-validate new equations for predicting resting energy expenditure (REE) in severely obese children and adolescents, and to determine the accuracy of new equations using the Bland–Altman method. The subjects of the study were 574 obese Caucasian children and adolescents (mean BMI z-score 3·3). REE was determined by indirect calorimetry and body composition by bioelectrical impedance analysis. Equations were derived by stepwise multiple regression analysis using a calibration cohort of 287 subjects and the equations were cross-validated in the remaining 287 subjects. Two new specific equations based on anthropometric parameters were generated as follows: (1) REE=(Sex×892·68)−(Age×115·93)+(Weight×54·96)+(Stature×1816·23)+1484·50 (R2 0·66; se 1028·97 kJ); (2) REE=(Sex×909·12)−(Age×107·48)+(fat-free mass×68·39)+(fat mass×55·19)+3631·23 (R2 0·66; se 1034·28 kJ). In the cross-validation group, mean predicted REE values were not significantly different from the mean measured REE for all children and adolescents, as well as for boys and for girls (difference <2 %) and the limits of agreement (±2 sd) were +2·06 and −1·77 MJ/d (NS). The new prediction equations allow an accurate estimation of REE in groups of severely obese children and adolescents. These equations might be useful for health care professionals and researchers when estimating REE in severely obese children and adolescents.
Dimensional representations of DSM-IV cluster B personality disorders in a population-based sample of Norwegian twins: a multivariate study
Authors: Torgersen S. , Czajkowski N. , Jacobson K. , Reichborn-Kjennerud T. , Røysamb E. , Neale M. C. , Kendler K. S.
Published: February 2008

Background

The personality disorders (PDs) in the ‘dramatic’ cluster B [antisocial (ASPD), histrionic (HPD), narcissistic (NPD) and borderline (BPD)] demonstrate co-morbidity. However, the degree to which genetic and/or environmental factors influence their co-occurrence is not known and, with the exception of ASPD, the relative impact of genetic and environmental risk factors on liability to the cluster B PDs has not been conclusively established.

Method

PD traits were assessed in 1386 Norwegian twin pairs between the age of 19 and 35 years using the Structured Interview for DSM-IV Personality Disorders (SIDP-IV). Using the statistical package Mx, multivariate twin models were fitted to dimensional representations of the PDs.

Results

The best-fitting model, which did not include sex or shared family environment effects, included common genetic and environmental factors influencing all four dramatic PD traits, and factors influencing only ASPD and BPD. Heritability was estimated at 38% for ASPD traits, 31% for HPD traits, 24% for NPD traits and 35% for BPD traits. BPD traits had the lowest and ASPD traits the highest disorder-specific genetic variance.

Conclusion

The frequently observed co-morbidity between cluster B PDs results from both common genetic and environmental influences. Etiologically, cluster B has a ‘substructure’ in which ASPD and BPD are more closely related to each other than to the other cluster B disorders.
DYNAMICS OF THE SAVING RATE IN THE NEOCLASSICAL GROWTH MODEL WITH CES PRODUCTION
Authors: GÓMEZ MANUEL A.
Published: February 2008

This paper characterizes the global dynamics of the saving rate in the neoclassical growth model with CES production. The study is based on qualitative phase-diagram analysis. The analytical conditions characterizing the cases that may arise theoretically depending on the parameters' configuration are obtained. It is well known that the saving rate behaves monotonically if technology is Cobb-Douglas. However, when the elasticity of substitution is nonunitary, the saving rate path may exhibit nonmonotonic behavior.
RAMSEY MONETARY POLICY WITH CAPITAL ACCUMULATION AND NOMINAL RIGIDITIES
Authors: FAIA ESTER
Published: February 2008

Recent literature on the design of optimal monetary policy has shown that deviations from price stability are small whenever prices are sticky. This paper reconsiders this issue by introducing capital accumulation in the model. Optimal monetary policy in this setup implies small deviations from price stability. The monetary authority optimally uses inflation as an explicit tax on monopolistic profits to reduce the price markup across states. Variable markup is achieved in this setup because the share of investment demand over output varies across states and in response to TFP shocks.
INDETERMINACY, BIFURCATIONS, AND UNEMPLOYMENT FLUCTUATIONS
Authors: DUFOURT FRÉDÉRIC , LLOYD-BRAGA TERESA , MODESTO LEONOR
Published: February 2008

We incorporate imperfectly insured unemployment in the finance constrained economy proposed by Woodford (1986), by introducing unions and unemployment benefits financed by labor taxation. We show that this simple extension of the Woodford model changes drastically its stability conditions and local dynamics around the steady state. In fact, in contrast to related models in the literature, we find that, under constant returns to scale in production: (i) indeterminacyalwaysprevails in the case of a unitary elasticity of substitution between capital and labor and (ii) flip and Hopf bifurcations occur for empirically credible elasticities of substitution between capital and labor, so that a rich set of dynamics may emerge at “realistic” parameters' values.
Rotavirus vaccines: how they work or don't work
Authors: Ward Richard L.
Published: February 2008

In 2004 and 2006, two new rotavirus vaccines – Rotarix™and RotaTeq™– were licensed worldwide. Both are live virus vaccines and are composed of either a monovalent attenuated human rotavirus or five bovine–human reassortant rotaviruses, respectively. Studies in humans and animals have reported correlations between rotavirus antibody levels and protection, the most consistent of which has been with rotavirus IgA. Cellular immunity was also found to have a role in protection after live rotavirus immunisation, particularly in mice. However, the primary importance of CD8+T cells may be in resolution of infection and that of CD4+T cells may be their helper function, particularly for antibody production. CD4+T cells have been reported to have a more direct role in protection after mucosal immunisation with non-living rotavirus vaccines, possibly because of direct or indirect effects of the cytokines they generate. Immune effectors have overlapping functions, and protection against rotavirus by either live or non-living vaccines is probably enhanced by this redundancy.
Strong Gravitational Lensing: Bright Galaxies & Lost Dark-Matter
Authors: Koopmans L. V. E.
Published: February 2008

Gravitational lensing and stellar dynamics provide two complementary methods to probe the smooth and clumpy stellar and dark-matter mass distribution in early-type galaxies, currently already over a range of two orders of magnitude in virial mass, more than ten orders of magnidude in dynamic mass range in each galaxy (i.e. from stars, CDM substructure to massive dark-matter halos), over 0–1 in redshift, and a range of 0–100 effective radii. This makes their unification a powerful new tool in the study of the formation, structure and evolution of these massive systems. I review recent results that we obtained, based on gravitational lens systems from the Sloan Lens ACS Survey (SLACS), and outline some ongoing and future work.
Scaling Relations of Dwarf Galaxies without Supernova-Driven Winds
Authors: Tassis K. , Kravtsov A. V. , Gnedin N. Y.
Published: February 2008

Nearby dwarf galaxies exhibit tight correlations between their global stellar and dynamical properties, such as circular velocity, mass-to-light ratio, stellar mass, surface brightness, and metallicity. Such correlations have often been attributed to gas or metal-rich outflows driven by supernova energy feedback to the interstellar medium. We use high-resolution cosmological simulations of high-redshift galaxies with and without energy feedback, as well as analytic modeling, to investigate whether the observed correlations can arise without supernova-driven outflows. We find that the simulated dwarf galaxies exhibit correlations similar to those observed as early as z ≈ 10 and the addition of realistic levels of supernova energy feedback has no appreciable effect on these correlations. We also show that the correlations can be well reproduced by our analytic model that accounts for gas inflow but without outflows, and star formation rate obeying the Kennicutt-Schmidt law with a critical density threshold. We argue that correlations in simulated galaxies arise due to the increasingly inefficient conversion of gas into stars in low-mass dwarf galaxies rather than supernova-driven outflows.
Dark-Matter Content of Early-Type Galaxies with Planetary Nebulae
Authors: Napolitano N. R. , Romanowsky A. J. , Coccato L. , Capaccioli M. , Douglas N. G. , Noordermeer E. , Merrifield M. R. , Kuijken K. , Arnaboldi M. , Gerhard O. , Freeman K. C. , De Lorenzi F. , Das P.
Published: February 2008

We examine the dark matter properties of nearby early-type galaxies using planetary nebulae (PNe) as mass probes. We have designed a specialised instrument, the Planetary Nebula Spectrograph (PN.S) operating at the William Herschel telescope, with the purpose of measuring PN velocities with best efficiency. The primary scientific objective of this custom-built instrument is the study of the PN kinematics in 12 ordinary round galaxies. Preliminary results showing a dearth of dark matter in ordinary galaxies (Romanowskyet al. 2003) are now confirmed by the first complete PN.S datasets. On the other hand early-type galaxies with a “regular” dark matter content are starting to be observed among the brighter PN.S target sample, thus confirming a correlation between the global dark-to-luminous mass virial ratio (fDM=MDMM*) and the galaxy luminosity and mass.
AGES Observations of Abell 1367
Authors: Cortese L. , Minchin R. F. , Auld R. R. , Davies J. I. , Catinella B. , Momjian E. , Rosenberg J. L. , Taylor R. , Gavazzi G. , O'Neil K.
Published: February 2008

We present 21 cm observations of 5×1 square degrees centered on the local Abell cluster 1367 obtained as part of the Arecibo Galaxy Environment Survey. This represents the first HI selected sample covering the core and the outskirts of a local cluster of galaxies. Combining the HI data with SDSS optical imaging we show that in HI selected samples follow scaling relations similar to the ones usually observed in optically selected samples. The most striking difference between HI and optically selected samples resides in their large scale distribution: while optical and X-ray observations trace the cluster potential very well, at radio wavelengths there is almost no evidence of the cluster presence.
Investigating the Relationship Between the Hot Gas and the Dark Matter Components of Galaxy Clusters.
Authors: Powell Leila C. , Kay Scott T. , Babul Arif , Mahdavi Andisheh
Published: February 2008

Various differences in galaxy cluster properties derived from X-ray and weak lensing observations have been highlighted in the literature. One such difference is the observation of mass concentrations in lensing maps which have no X-ray counterparts (e.g. Jee, White, Ford et al. 2005). We investigate this issue by identifying substructures in maps of projected total mass (analogous to weak lensing mass reconstructions) and maps of projected X-ray surface brightness for three simulated clusters. We then compare the 2D mass substructures with both 3D subhalo data and the 2D X-ray substructures. Here we present preliminary results from the first comparison, where we have assessed the impact of projecting the data on subhalo identification.
Searching for Dark Galaxies: The AGES VC2 Region
Authors: Taylor R. , Auld R. , Cortese L. , Davies J. , Minchin R.
Published: February 2008

The VC2 strip (part of the AGES blind HI survey) spans 5x1 degrees of the Virgo Cluster, from the outskirts of the cluster to its interior. The strip covers part of subcluster A while avoiding the strong continuum source M87. 40 hours of observations were taken in January-February 2007 using the ALFA instrument on the Arecibo telescope, reaching a noise level as low as 0.5 mJy. For a 200 km/s velocity width, this gives a sensitivity limit of 6*106 Msolar at the Virgo distance (16 Mpc). Currently, 36 definite sources have been found, both by eye and with the automatic extractor Polyfind, with an additional 12 requiring follow-up observations, found only by one method.
Riverine particulate organic carbon from an active mountain belt: Importance of landslides
Authors: Hilton Robert G. , Galy Albert , Hovius Niels
Published: February 2008

We investigate the routing and transfer of particulate organic carbon (POC) from the western Southern Alps, New Zealand, using organic carbon (Corg) and nitrogen (Norg) concentrations and stable carbon isotopes (δ13Corg). In this active mountain belt, sediment discharge is dominated by landslide‐derived material. Landsliding acts to homogenize the geochemically diverse hillslope POC, mixing POC from the standing biomass and soil with the fossil POC from bedrock. As a result, the POC in river sediment at the mountain front is a binary mixture of fossil and nonfossil carbon sourced from many landslide deposits. We calculate that nonfossil biogenic POC makes up 63 ± 7% of the total POC in the suspended load of rivers draining the western Southern Alps. The erosional flux of biogenic POC from these catchments represents a transfer of 39 tC km−2 a−1 of atmospheric CO2 averaged over the west flank of the mountain belt. If more than 10% of this POC is preserved in sediments on geological timescales, then this process is the most significant way in which the Southern Alps and similar, tectonically active mountain belts with restricted alluvial aprons consume atmospheric CO2.
Aerial observations of floe size distribution in the marginal ice zone of summer Prydz Bay
Authors: Lu P. , Li Z. J. , Zhang Z. H. , Dong X. L.
Published: February 2008

On the basis of aerial photographs of sea ice floes in the marginal ice zone (MIZ) of Prydz Bay acquired from December 2004 to February 2005 during the 21st Chinese National Antarctic Research Expedition, image processing techniques are employed to extract some geometric parameters of floes from two merged transects covering the whole MIZ. Variations of these parameters with the distance into the MIZ are then obtained. Different parameters of floe size, namely area, perimeter, and mean caliper diameter (MCD), follow three similar stages of increasing, flat and increasing again, with distance from the open ocean. Floe shape parameters (roundness and the ratio of perimeter to MCD), however, have less significant variations than that of floe size. Then, to modify the deviation of the cumulative floe size distribution from the ideal power law, an upper truncated power‐law function and a Weibull function are used, and four calculated parameters of the above functions are found to be important descriptors of the evolution of floe size distribution in the MIZ. Among them, Lr of the upper truncated power‐law function indicates the upper limit of floe size and roughly equals the maximum floe size in each square sample area. L0 in the Weibull distribution shows an increasing proportion of larger floes in squares farther from the open ocean and roughly equals the mean floe size. D in the upper truncated power‐law function is closely associated with the degree of confinement during ice breakup. Its decrease with the distance into MIZ indicates the weakening of confinement conditions on floes owing to wave attenuation. The γ of the Weibull distribution characterizes the degree of homogeneity in a data set. It also decreases with distance into MIZ, implying that floe size distributes increase in range. Finally, a statistical test on floe size is performed to divide the whole MIZ into three distinct zones made up of floes of quite different characteristics. This zonal structure of floe size also agrees well with the trends of floe shape and floe size distribution, and is believed to be a straightforward result of wave‐ice interaction in the MIZ.
Mantle flow in the South Sandwich subduction environment from source‐side shear wave splitting
Authors: Müller Christian , Bayer Bettina , Eckstaller Alfons , Miller Heinrich
Published: February 2008

The occurrence of seismic anisotropy in the Earth's upper mantle is a global phenomenon related to subcrustal deformation and flow processes. The shear wave splitting analysis method has led to a global set of anisotropy maps mainly derived from receiver‐side analysis. Remote places with few seismometers deployed remain unexamined. Source‐side splitting analysis allows mapping of mantle fabrics in these regions. Here, we investigate seismic anisotropy in the South Sandwich Islands subduction environment. Core‐reflected ScS waves recorded at the Neumayer seismograph network are corrected for well constrained receiver anisotropy and then analysed for source anisotropy. Sub‐slab mantle minerals are aligned horizontally almost parallel to the trench indicating a westward flow around the subducting slab. This is consistent with a model of horizontal mantle flow due to slab rollback that was previously inferred from marine and geochemical studies in the back‐arc region.
Effect of solar wind density on relativistic electrons at geosynchronous orbit
Authors: Lyatsky Wladislaw , Khazanov George V.
Published: February 2008

We examined the relationship between relativistic (>2 MeV) electron fluxes at geostationary orbit and two solar wind parameters, the speed and density. For the analysis, we used data of relativistic electron fluxes measured with GOES‐8 spacecraft for 1997–2002 and GOES‐10 spacecraft for 2003–2006, and solar wind data, provided by Goddard Space Flight Center. Using the correlation analysis, we found that not only solar wind speed but also solar wind density provides a strong effect on relativistic electrons: the relativistic electron fluxes increase with increasing solar wind speed and decrease with increasing solar wind density. In contrast to solar wind speed that shows the best correlation with electron fluxes after about two days only, the solar wind density shows the best correlation with the electron fluxes after about 15 hours. To separate the effects of solar wind speed and density, we examined events when solar wind speed varied insignificantly; in these events, the effect of solar wind density on the relativistic electrons remained strong. We found that the solar wind density, which may affect the loss of relativistic electrons, effectively controls the magnitude of relativistic electron fluxes at geostationary orbit, so that the strongest fluxes occurred almost exclusively during low‐density solar wind conditions. Thus, our study showed that solar wind density is an important parameter that may significantly affect the loss of relativistic electrons and, as a result, the resulting magnitude of the electron fluxes at geostationary orbit.
Bow shock contributions to region 1 field‐aligned current: A new result from global MHD simulations
Authors: Guo X. C. , Wang C. , Hu Y. Q. , Kan J. R.
Published: February 2008

We present a new result, based on a global MHD simulation model, that the bow shock contributes significantly to the region 1 field‐aligned current (FAC) under strong southward interplanetary magnetic field conditions. More than 50 percent of the total region 1 FAC may originate from the bow shock in certain circumstances. Stronger southward interplanetary magnetic field, higher solar wind speed, or larger ionospheric Pedersen conductance, leads to greater contribution from the bow shock to the region 1 current. This new result quantifies the interaction between the bow shock and the ionosphere through the region 1 current. The methodology presented in the present paper should be applicable to quantify the bow shock contributions to the substorms through the region 1 current, as well as to the magnetic storms through the ring current and the region 2 current, leading to understanding the space weather as magnetic storms in the solar‐terrestrial environment.
Correlation between pressure gradient and phase saturation for oil‐water flow in smooth‐ and rough‐walled parallel‐plate models
Authors: Wong R. C.‐K. , Pan X. , Maini B. B.
Published: February 2008

The present study is aimed at an investigation of the pressure gradient/phase saturation correlation in the flow of an oil‐water mixture through a parallel‐plate (single fracture) model. It was found that the correlation depends on the interaction between the two flowing fluids, or flow pattern, which is in turn governed by the injection method, water flow rate, viscosity ratio, fracture aperture, and fracture surface roughness. Three distinct flow patterns were identified, namely, channel, dispersed, and mixed flows. Measurements of pressure gradient and phase saturation suggest that the widely used Romm's relative permeability relationship is applicable to channel flow in which oil and water phases are continuous in the fracture. For dispersed or mixed flow in which either the oil or water phase is discontinuous, a Lockhart‐Martinelli type correlation developed for gas‐liquid flow in pipes should be valid at low viscosity ratio but not at high viscosity ratio and water flow rate.
Geomorphic structure of tidal hydrodynamics in salt marsh creeks
Authors: Fagherazzi Sergio , Hannion Muriel , D'Odorico Paolo
Published: February 2008

This paper develops a geomorphological theory of tidal basin response (tidal instantaneous geomorphologic elementary response, or TIGER) to describe specific characteristics of tidal channel hydrodynamics. On the basis of the instantaneous unit hydrograph approach, this framework relates the hydrodynamics of tidal watersheds to the geomorphic structure of salt marshes and, specifically, to the distance traveled by water particles within the channel network and on the marsh surface. The possibility of determining the water fluxes from observations of geomorphic features is an appealing approach to the study of tidally driven flow rates. Our formulation paves the way to the application of recent results on the geomorphic structure of salt marshes and tidal networks to the determination of marsh creek hydrology. A case study shows how the asymmetry in the stage‐velocity relation and the existence of velocity surges typical of the tidal hydrographs can be explained as an effect of the delay in the propagation of the tidal signal within the marsh area.
The cell biology of cross‐presentation and the role of dendritic cell subsets
Authors: Lin Ming‐Lee , Zhan Yifan , Villadangos Jose A , Lew Andrew M
Published: February 2008

The cell biology of cross‐presentation is reviewed regarding exogenous antigen uptake, antigen degradation and entry into the major histocompatibility complex class I pathway. Whereas cross‐presentation is not associated with enhanced phagocytic ability, certain receptors may favour uptake for cross‐presentation for example mannose receptor for soluble glycoproteins. Perhaps, the defining property of the cross‐presenting cell is some specialization in host machinery for handling and transport of antigen across organelles. Both cytosolic and vacuolar pathways are discussed. Which dendritic cell (DC) subset is the cross‐presenting cell is explored. Cross‐presentation is found within the CD8+ subset resident in lymphoid organs. The role of other DC subsets (especially the migratory CD8− DC) and the route of antigen delivery are also discussed. Further consideration is given to antigen transfer between DC subsets and differential presentation to naive vs memory T cells.
Selective recruitment of bacteria during embryogenesis of an earthworm
Authors: Davidson Seana K , Stahl David A
Published: February 2008

Earthworms of the family Lumbricidae harbor specific and stable populations of Acidovorax-like bacteria within their excretory organs, the nephridia. The symbionts of Eisenia foetida are deposited into the egg capsules during mating and the nephridia of the juveniles are colonized before they hatch. The timing and mechanisms governing bacterial recruitment and colonization are unknown for the earthworm-Acidovorax association. This study examined the process of colonization of the symbiotic organ during development of the embryos within the egg capsules. Bacteria associated with the developing embryos were visualized using in situ hybridization to bacterial cells and laser scanning confocal microscopy. Bacterial cells were associated with earthworm embryos during the earliest stages of development—the ova through to hatching. Three-dimensional examination of stages of development revealed an embryonic duct that recruits the Acidovorax-like symbiont cells. As each segment matures, Acidovorax-like symbiotic bacteria are recruited into this duct, excluding most other bacterial types, and remain there for a period of days prior to migration into the nephridium. After colonization of the nephridial ampulla, the canal remains bacteria-free. In addition to the known Acidovorax-like bacteria, multiple types of bacteria interact with the embryos externally and internally during the full course of development, and ultimately fill the gut lumen near the end of development prior to hatching. Colonization of the correct tissues by specific bacteria during differentiation and maturation of the organs must involve selective host defenses and signaling between the two partners to prevent over growth of nascent tissues.
‘Iron‐saturated’ lactoferrin is a potent natural adjuvant for augmenting cancer chemotherapy
Authors: Kanwar Jagat R , Palmano Kate P , Sun Xueying , Kanwar Rupinder K , Gupta Rita , Haggarty Neill , Rowan Angela , Ram Satyendra , Krissansen Geoffrey W
Published: February 2008

Bovine lactoferrin (bLf), an iron‐containing natural defence protein found in bodily secretions, has been reported to inhibit carcinogenesis and the growth of tumours. Here, we investigated whether natural bLf and iron‐saturated forms of bLf differ in their ability to augment cancer chemotherapy. bLf was supplemented into the diet of C57BL/6 mice that were subsequently challenged subcutaneously with tumour cells, and treated by chemotherapy. Chemotherapy eradicated large (0.6 cm diameter) EL‐4 lymphomas in mice that had been fed iron‐saturated bLf (here designated Lf+) for 6 weeks prior to chemotherapy, but surprisingly not in mice that were fed lesser iron‐saturated forms of bLf, including apo‐bLf (4% iron saturated), natural bLf (∼15% iron saturated) and 50% iron‐saturated bLf. Lf+‐fed mice bearing either EL‐4, Lewis lung carcinoma or B16 melanoma tumours completely rejected their tumours within 3 weeks following a single injection of either paclitaxel, doxorubicin, epirubicin or flurouracil, whereas mice fed the control diet were resistant to chemotherapy. Lf+ had to be fed to mice for more than 2 weeks prior to chemotherapy to be wholly effective in eradicating tumours from all mice, suggesting that it acts as a competence factor. It significantly reduced tumour vascularity and blood flow, and increased antitumour cytotoxicity, tumour apoptosis and the infiltration of tumours by leukocytes. Lf+ bound to the intestinal epithelium and was preferentially taken up within Peyer's patches. It increased the production of Th1 and Th2 cytokines within the intestine and tumour, including TNF, IFN‐γ, as well as nitric oxide that have been reported to sensitize tumours to chemotherapy. Importantly, it restored both red and white peripheral blood cell numbers depleted by chemotherapy, potentially fortifying the mice against cancer. In summary, bLf is a potent natural adjuvant and fortifying agent for augmenting cancer chemotherapy, but needs to be saturated with iron to be effective.
The 67 kDa laminin receptor: structure, function and role in disease
Authors: Nelson John , McFerran Neil V. , Pivato Géraldine , Chambers Emma , Doherty Caroline , Steele David , Timson David J.
Published: February 2008

The 67LR (67 kDa laminin receptor) is a cell-surface receptor with high affinity for its primary ligand. Its role as a laminin receptor makes it an important molecule both in cell adhesion to the basement membrane and in signalling transduction following this binding event. The protein also plays critical roles in the metastasis of tumour cells. Isolation of the protein from either normal or cancerous cells results in a product with an approx. molecular mass of 67 kDa. This protein is believed to be derived from a smaller precursor, the 37LRP (37 kDa laminin receptor precursor). However, the precise mechanism by which cytoplasmic 37LRP becomes cell-membrane-embedded 67LR is unclear. The process may involve post-translational fatty acylation of the protein combined with either homo- or hetero-dimerization, possibly with a galectin-3-epitope-containing partner. Furthermore, it has become clear that acting as a receptor for laminin is not the only function of this protein. 67LR also acts as a receptor for viruses, such as Sindbis virus and dengue virus, and is involved with internalization of the prion protein. Interestingly, unmodified 37LRP is a ribosomal component and homologues of this protein are found in all five kingdoms. In addition, it appears to be strongly associated with histones in the eukaryotic cell nucleus, although the precise role of these interactions is not clear. Here we review the current understanding of the structure and function of this molecule, as well as highlighting areas requiring further research.
A novel β-myosin heavy chain gene mutation, p.Met531Arg, identified in isolated left ventricular non-compaction in humans, results in left ventricular hypertrophy that progresses to dilation in a mouse model
Authors: Kaneda Tomoya , Naruse Chie , Kawashima Atsuhiro , Fujino Noboru , Oshima Toru , Namura Masanobu , Nunoda Shinichi , Mori Sumio , Konno Tetsuo , Ino Hidekazu , Yamagishi Masakazu , Asano Masahide
Published: February 2008

Mutations in the βMHC (β-myosin heavy chain), a sarcomeric protein are responsible for hypertrophic and dilated cardiomyopathy. However, the mechanisms whereby distinct mutations in the βMHC gene cause two kinds of cardiomyopathy are still unclear. In the present study we report a novel βMHC mutation found in a patient with isolated LVNC [LV (left ventricular) non-compaction] and the phenotype of a mouse mutant model carrying the same mutation. To find the mutation responsible, we searched for genomic mutations in 99 unrelated probands with dilated cardiomyopathy and five probands with isolated LVNC, and identified a p.Met531Arg mutation in βMHC in a 13-year-old girl with isolated LVNC. Next, we generated six lines of transgenic mice carrying a p.Met532Arg mutant αMHC gene, which was identical with the p.Met531Arg mutation in the human βMHC. Among these, two lines with strong expression of the mutant αMHC gene were chosen for further studies. Although they did not exhibit the features characteristic of LVNC, approx. 50% and 70% of transgenic mice in each line displayed LVH (LV hypertrophy) by 2–3 months of age. Furthermore, LVD (LV dilation) developed in approx. 25% of transgenic mice by 18 months of age, demonstrating biphasic changes in LV wall thickness. The present study supports the idea that common mechanisms may be involved in LVH and LVD. The novel mouse model generated can provide important information for the understanding of the pathological processes and aetiology of cardiac dilation in humans.