bluuebunny/crossref_metadata_2025 huggingface dataset:
Do intense electromagnetic fields annihilate∕create conical intersections?
Authors: Sarkar Biplab , Adhikari Satrajit , Baer Michael
Published: January 2007

In this article the authors relate the possibility that an intense electric field affects topological features of a molecular system. For this purpose they studied a model based on the Mathieu equation. They found that such a field may affect the spatial distribution of the nonadiabatic coupling terms but not the position of the intersections. In other words an intense electric field does not create or annihilate conical intersections. It is shown that this conclusion is valid as long as the field is an analytic function of the coordinates in the region of interest. These findings can be extended to magnetic fields (or electromagnetic fields) as long as they are analytic functions in the region of interest.
Photoionization affected by chemical anisotropy
Authors: Gladkikh V. S. , Burshtein A. I.
Published: January 2007

The kinetic constants of rhodamine 3B quenching by N,N-dimethyl aniline were extracted from the very beginning of the quenching kinetics, recently studied in a few solvents of different viscosities. They were well fitted with the conventional kinetic constant definition, provided the radial distribution function of simple liquids was ascribed to the reactant pair distribution and the contact electron transfer rate was different in all the cases. This difference was attributed to the chemical anisotropy averaging by the rotation of reactants, which is the faster in solvents of lower viscosity. With the proper choice of a space dependent encounter diffusion, the whole quenching kinetics was well fitted with an encounter theory, using the Marcus [J. Chem. Phys. 24, 966 (1956); 43, 679 (1965)] transfer rate instead of the contact Collins-Kimball [J. Colloid. Sci. 4, 425 (1949)] approximation. Not only the beginning and middle part of the quenching were equally well fitted, but the long time (Markovian) rate constant was also found to be the same as previously obtained. Moreover, the concentration dependencies of the fluorescence quantum yield and the Stern-Volmer constant were specified and await their experimental verification.
Isotropic Brillouin spectra of liquids having an internal degree of freedom
Authors: Patkowski A. , Gapinski J. , Meier G. , Kriegs H.
Published: January 2007

Isotropic Brillouin spectra of the two chemically similar van der Waals glass forming liquids, 1,1′-di(4-methoxy-5-methylphenyl)cyclohexane (BMMPC) and 1,1′-bis(p-methoxy-phenyl)cyclohexane (BMPC) and ortho-terphenyl (OTP), were studied in a broad temperature and pressure range in order to characterize the effect of internal relaxations on the damping of longitudinal phonons. Such relaxations are present in BMPC, while in BMMPC and OTP they are strongly hindered. The authors show that in BMPC (with strong internal relaxations) the damping (broadening) of longitudinal phonons (Brillouin peaks) is much stronger than in BMMPC and OTP (with weaker internal relaxations). The contributions of the internal and structural relaxations to the phonon damping can be separated using high pressure, due to their very different pressure dependences. They show that internal relaxations strongly contribute to the damping of longitudinal phonons at all temperatures and should be taken into account in theoretical models describing the Brillouin spectra of supercooled liquids.
Double bands of negative refractive index in the left-handed metamaterials with asymmetric defects
Authors: Zhu Weiren , Zhao Xiaopeng , Ji Ning
Published: January 2007

The authors present a left-handed metamaterial (LHM) with asymmetric defects at microwave frequencies. The LHM is composed of the periodic arrays of hexagonal split ring resonators and wires, and the defects are introduced into the integrated LHM. It is shown with beam shifting experiment that the transmittance spectrum of the sample appears to have two peaks with maximum value frequencies of 9.10 and 9.80GHz, and double bands of negative refractive index, n=−0.48 and n=−1.09, are clearly found. The LHM proposed here offers the potential applications such as bandpass filters, wavelength divider, and antennas.
On the uniqueness of Fourier Jacobi models for representations of 𝑈(𝑛,1)
Authors: Baruch Ehud , Rallis Stephen
Published: January 2007

We show that every irreducible unitary representation of

U
(
n
,
1
)

U(n,1)

, has at most one Fourier Jacobi model.
Expression of mRNA electroporated into plant and animal cells
Authors: Callis J. , Fromm M. , Walbot V.
Published: January 2007

A general method to introduce RNA molecules into plant protoplasts and animal cells is described. This technique utilizes the ability of electric pulses of high field strength to form pores in biomembranes. RNA molecules containing the coding region for the bacterial enzyme chloramphenicol acetyltransferase (CAT) were used as a model system. The presence of CAT activity as a result of the in vivo translation of the introduced RNA is entirely dependent on the presence of a 5′ cap and greatly increased by the presence of a poly A tail at the 3′ end. The introduction of RNA into eukaiyotic cells has broad applicability both as an assay for the uptake of nucleic acids into cells independent of transcriptional activity and as a tool to study eukaryotic mRNA translation.
A novel method for the purification of the Xenopus transcription factor IIIA
Authors: Miller J. , Fairall L. , Rhodes D.
Published: January 2007

We have developed a quick and simple purification method that yields large quantities of the Xenopus zinc finger protein transcription factor IIIA (TFIIIA). The protein is purified in the form of the 7S storage particle (TFIIIA/5S RNA complex) found in the ovaries of immature Xenopus. Our method yields 0.5 to 1 mg of pure 7S particle per ovary. It involves a high speed centrifugation step, fractionation on a gel filtration column and a precipitation step using calcium chloride. TFIIIA purified using this protocol retains full DNA binding activity and has the expected zinc ion content.
THE SUPERCRITICAL SPATIALLY HOMOGENEOUS THERMAL EXPLOSION: INITIATION TO COMPLETION
Authors: KASSOY D. R.
Published: January 2007

A complete solution (initiation to completion) is developed for the spatially homogeneous model of a thermal explosion with heat loss. The temperature, time history and the concomitant reactant consumption are described in detail. A matched asymptotic expansion procedure is developed to describe the solution in six successive time zones. Each of these is characterized by distinct physical processes and their duration, which varies widely. Of particular interest are the extremely rapid processes which characterize a truly explosive event.
Germ cell proliferation and apoptosis during different phases of swordfish (Xiphias gladius L.) spermatogenetic cycle
Authors: Corriero A. , Desantis S. , Bridges C. R. , Kime D. E. , Megalofonou P. , Santamaria N. , Cirillo F. , Ventriglia G. , Di Summa A. , Deflorio M. , Campobasso F. , De Metrio G.
Published: January 2007

Seasonal changes of testicular activity of the swordfish Xiphias gladius and correlations of plasma levels of testosterone (T) and 11‐ketotestosterone (11‐KT) with proliferation and apoptosis of germ cells, determined, respectively, with monoclonal antibodies against proliferating cell nuclear antigen and terminal deoxynucleotidyl transferase‐mediated d’UTP nick end labelling, are described. Three phases of the reproductive cycle were found: active spermatogenic (May), spawning (June to July) and spent (August to September) stages. Germ cell proliferating activity was highest in May, decreased during June to July and remained stable during August to September. Apoptotic germ cells, primary spermatocytes and spermatogonia, were present in all the specimens analysed and were more abundant in May. The levels of 11‐KT in plasma were always higher than T and were highest in May, in concomitance with the maximum proliferation and apoptosis rate of germ cells.
Nitrogen and phosphorus content of some temperate and tropical freshwater fishes
Authors: Dantas M. C. , Attayde J. L.
Published: January 2007

The nitrogen and phosphorus content of two temperate fishes, Rutilus rutilus and Perca fluviatilis, and six tropical fishes, Oreochromis niloticus, Cichla monoculus, Serrassalmus rhombeus, Plagioscion squamosissimus, Prochilodus brevis and Hoplias malabaricus, were investigated to test the hypothesis that variation in body P content and N:P ratio is related to body size. Regressions of %P and N:P ratios against fish size (length and mass) confirmed the hypothesis for P. fluviatilis and P. squamosissimus, suggesting that body size is an important factor driving body P content and N:P ratios in some fishes. Moreover, significant increases in %N and N:P ratio with body size was found for H. malabaricus, a common piscivorous fish of the Neotropics. Interspecific variation in %P and N:P ranged two‐fold and significant differences (P < 0·05) were found among the tested species. The mean ±s.d. elemental content across all fishes (n= 170) was 10·35 ± 1·29% for N and 3·05 ± 0·82% for P, while the N:P ratio was 8·00 ± 2·14. Data on fish body nutrient content and ratio will improve parameterization of bioenergetics and mass balance models and help clarify the role of fishes in nutrient cycles in both temperate and tropical freshwaters.
Elemental stoichiometry of freshwater fishes in relation to phylogeny, allometry and ecology
Authors: Hendrixson H. A. , Sterner R. W. , Kay A. D.
Published: January 2007

Twenty species of freshwater fishes were collected from Minnesota, Iowa and Michigan and their whole‐body carbon, nitrogen and phosphorus contents and the respective C:N:P ratios were determined. Patterns were examined in intra‐ and interspecific variation, allometry and variation caused by habitat and trophic level in whole fish while controlling for the role of phylogeny. Stoichiometric variation was greater across than within species, C:N:P allometry was species‐specific, nutrient content within a species was somewhat habitat‐specific and P concentration showed a strong phylogenetic signal. Stoichiometric relationships with allometry and feeding guild were observed but were not significant in an analysis accounting for non‐independence of closely related species. Supportive evidence for the hypothesis that the considerable variation in whole fish phosphorus concentrations could be ascribed to differences in bone and scale development, as previously suggested, is shown. Whole fish Ca:P ratios had a nearly constant stoichiometry consistent with the chemical signature of bone. This result combined with a phylogenetic signal for fish P indicated that the great stoichiometric variability among fish taxa in P content was derived almost entirely from skeletal investment.
The effect of habitat heterogeneity on the population density of juvenile Atlantic salmon Salmo salar L.
Authors: Dolinsek I. J. , Grant J. W. A. , Biron P. M.
Published: January 2007

In each of eight sites in 2 years in Catamaran Brook and the Little Southwest Miramichi River, in New Brunswick, Canada, 36 boulders (median diameter = 0·20 m) were added to a 2 × 3 m quadrat in one treatment, all boulders were removed in another treatment, and one quadrat was left as a control. As predicted, adding boulders increased the density of salmonid fishes, primarily juvenile Atlantic salmon Salmo salar, by 2·8‐fold, but had no significant effect on non‐territorial fishes, primarily cyprinids and catostomids. Moreover, the effect of adding boulders was greatest for age 0+ year Atlantic salmon, intermediate for age 1+ year Atlantic salmon and had no effect on age 2+ year Atlantic salmon. The results suggest that adding boulders is an effective short‐term technique for increasing the density of stream‐dwelling salmonids.
Westward range expansion of the Lessepsian migrant Fistularia commersonii (Fistulariidae) in the Mediterranean Sea, with notes on its parasites
Authors: Pais A. , Merella P. , Follesa M. C. , Garippa G.
Published: January 2007

One adult female bluespotted cornetfish Fistularia commersonii was captured near the coast of Arbatax (Sardinia, Italy) in late October 2005. Macroscopic and microscopic analysis of the gonad revealed a postspawning ovary. Several body parts of the damselfish Chromis chromis were found in its stomach contents. Different developmental stages of 58 metazoan parasites belonging to Arthropoda, Nematoda and Platyhelminthes were detected in its mouth and digestive tract. The lepocreadiid Allolepidapedon fistulariae was reported for the first time from the Mediterranean and, with the exception of this species, all the parasites found were reported for the first time in this host. This new record of F. commersonii may confirm the rapid range expansion of this Lessepsian migrant in the western Mediterranean Sea, as well as the presence of its endoparasite A. fistulariae.
Circulating levels of copeptin, a novel biomarker, in lower respiratory tract infections
Authors: Müller B. , Morgenthaler N. , Stolz D. , Schuetz P. , Müller C. , Bingisser R. , Bergmann A. , Tamm M. , Christ‐Crain M.
Published: January 2007

Background  Vasopressin has haemodynamic as well as osmoregulatory effects, and reflects the individual stress response. Copeptin is cosynthesized with vasopressin, directly mirroring vasopressin levels, but is more stable in plasma and serum. Both levels are increased in patients with septic shock. Lower respiratory tract infections (LRTI) are a precursor of sepsis. Thus, we investigated circulating levels and the prognostic use of copeptin for the severity and outcome in patients with LRTI.

Materials and methods  Five hundred and forty‐five consecutive patients with LRTI and 50 healthy controls were evaluated. Serum copeptin levels were measured with a new chemiluminescens sandwich immunoassay.

Results  Of the 545 patients, 373 had community‐acquired pneumonia (CAP), 60 acute exacerbations of chronic obstructive pulmonary disease (COPD), 59 acute bronchitis, 13 exacerbations of asthma and 40 other final diagnoses. Copeptin levels were significantly higher in patients with LRTI as compared to controls (P < 0·001) with highest levels in patients with CAP. Copeptin levels increased with increasing severity of CAP, as classified by the pneumonia severity index (PSI) (P < 0·001). In patients who died, copeptin levels on admission were significantly higher as compared to levels in survivors [70·0 (28·8–149·0) vs. 24·3 (10·8–43·8) pmol L−1, P < 0·001]. The area under the receiver operating curve (AUC) for survival was 0·75 for copeptin, which was significantly higher as compared to C‐reactive protein (AUC 0·61, P = 0·01), leukocyte count (AUC 0·59, P = 0·01) and similar to procalcitonin (AUC 0·68, P = 0·21).

Conclusions  Copeptin levels are increased with increasing severity of LRTI namely in patients with CAP and unfavourable outcome. Copeptin levels, as a novel biomarker, might be a useful tool in the risk stratification of patients with LRTI.
Expression profiling of PC‐3 cell line variants and comparison of MIC‐1 transcript levels in benign and malignant prostate
Authors: Patrikainen L. , Porvari K. , Kurkela R. , Hirvikoski P. , Soini Y. , Vihko P.
Published: January 2007

Background  The mechanisms behind prostate cancer progression are largely unknown, but macrophage inhibitory cytokine 1 (MIC‐1) has been suggested to be involved in tumour dissemination in vivo due to its reductive effect on cell adhesion.

Materials and methods  We used two PC‐3 prostate cancer epithelial cell line variants as tools to screen for gene expression differences during prostate cancer progression by cDNA microarray analysis. Selected genes were further analysed by Northern blot analysis using mRNA isolated from prostatic cell lines and tissues. MIC‐1 expression was studied by in situ hybridization in archival patient specimens containing benign and malignant prostatic tissue.

Results  Gene expression of human collagen type VI, basement membrane heparan sulphate proteoglycan, integrin alpha 1, and fibronectin I were remarkably decreased in suspension‐adapted PC‐3 (saPC‐3) cells, indicating a gene expression profile of reduced cell adhesion. Asparagine synthetase, serine protease 1, stanniocalcin homologue, NAD‐dependent methylene tetrahydrate dehydrogenase cyclohydrolase (NMDMC), fortilin, and MIC‐1 were overexpressed in saPC‐3 cells. In prostate, the MIC‐1 gene was mainly expressed in cancer tissue. However, MIC‐1 transcripts were detected in benign tissue areas, especially in specimens containing prostate cancer with Gleason sum scores of 5–8. A significant inverse correlation (Spearman's rho correlation coefficient −0·928**) was observed between the ratio of cancerous to benign MIC‐1 expression levels and Gleason scores.

Conclusions  Differential expression of the MIC‐1 gene occurs during prostate cancer progression. The transcript level of the MIC‐1 gene in histologically benign tissue seems to approach that in paired cancer tissue concomitant with an increasing Gleason score.
Stoneley wave generation by an incident P‐wave propagating in the surrounding formation across a horizontal fluid‐filled fracture
Authors: Ionov Andrei M.
Published: January 2007

This study investigates the generation of the low‐frequency borehole Stoneley wave (tube wave) by a plane P‐wave propagating through the surrounding elastic formation, which is intersected by a fluid‐filled fracture. A model is constructed taking into account the dynamic fluid coupling between the borehole interior and the fluid‐filled fracture of infinite extent with parallel walls. The basic mechanism of such coupling is due to the contraction of the fracture walls by the incident P‐wave, leading to seismic radiation into the fracture. The dynamic fluid flux from the fracture into the borehole interior, and vice versa, is the source of the low‐frequency Stoneley wave. An expression for the monopole pressure source, exciting the tube wave, is obtained.

The tube‐wave equation in the long‐wave approximation is derived in the presence of a fluid‐filled fracture of infinite extent. Amplitudes and waveforms of Stoneley waves are analysed in the seismic wavelength range for P‐wave pulses of various shapes. It is shown that the amplitude and waveform of the Stoneley wave depends significantly on the two dimensionless parameters of the problem: (1) the ratio of the borehole radius to the dominant wavelength of the incident pulse; (2) the ratio of the fracture width to the borehole radius. It is found that the amplitude of the generated Stoneley wave can be of the order of the P‐wave amplitude in the borehole fluid. Stoneley waveforms are found to be completely different from those of the incident pulse.
Appraisal of the consequences of the DDT‐induced bottleneck on the level and geographic distribution of neutral genetic variation in Canadian peregrine falcons,Falco peregrinus
Authors: BROWN JOSEPH W. , VAN COEVERDEN DE GROOT PETER J. , BIRT TIM P. , SEUTIN GILLES , BOAG PETER T. , FRIESEN VICKI L.
Published: January 2007

Peregrine falcon populations underwent devastating declines in the mid‐20th century due to the bioaccumulation of organochlorine contaminants, becoming essentially extirpated east of the Great Plains and significantly reduced elsewhere in North America. Extensive re‐introduction programs and restrictions on pesticide use in Canada and the United States have returned many populations to predecline sizes. A proper population genetic appraisal of the consequences of this decline requires an appropriate context defined by (i) meaningful demographic entities; and (ii) suitable reference populations. Here we explore the validity of currently recognized subspecies designations using data from the mitochondrial control region and 11 polymorphic microsatellite loci taken from 184 contemporary individuals from across the breeding range, and compare patterns of population genetic structure with historical patterns inferred from 95 museum specimens. Of the three North American subspecies, the west coast marine subspeciesFalco peregrinus pealeiis well differentiated genetically in both time periods using nuclear loci. In contrast, the partitioning of continentalFalco peregrinus anatumand arcticFalco peregrinus tundriussubspecies is not substantiated, as individuals from these subspecies are historically indistinguishable genetically. Bayesian clustering analyses demonstrate that contemporary genetic differentiation between these two subspecies is mainly due to changes withinF. p. anatum(specifically the southernF. p. anatumpopulations). Despite expectations and a variety of tests, no genetic bottleneck signature is found in the identified populations; in fact, many contemporary indices of diversity are higher than historical values. These results are rationalized by the promptness of the recovery and the possible introduction of new genetic material.
Mass-Independent Sulfur Isotopic Compositions in Stratospheric Volcanic Eruptions
Authors: Baroni Mélanie , Thiemens Mark H. , Delmas Robert J. , Savarino Joël
Published: January 2007

The observed mass-independent sulfur isotopic composition (Δ
33
S) of volcanic sulfate from the Agung (March 1963) and Pinatubo (June 1991) eruptions recorded in the Antarctic snow provides a mechanism for documenting stratospheric events. The sign of Δ
33
S changes over time from an initial positive component to a negative value. Δ
33
S is created during photochemical oxidation of sulfur dioxide to sulfuric acid on a monthly time scale, which indicates a fast process. The reproducibility of the results reveals that Δ
33
S is a reliable tracer to chemically identify atmospheric processes involved during stratospheric volcanism.
All Is Not Always Lost When the Center Does Not Hold
Authors: Morrison Kathleen D.
Published: January 2007

After Collapse
. The Regeneration of Complex Societies.
Glenn M. Schwartz and John J. Nichols, Eds.
. University of Arizona Press, Tucson, AZ, 2006. 295 pp. $50. ISBN 97808165096.

The contributors discuss a series of case studies from around the world to explore how some early complex societies reappeared after periods of decentralization and disruption.
A Hexanucleotide Element Directs MicroRNA Nuclear Import
Authors: Hwang Hun-Way , Wentzel Erik A. , Mendell Joshua T.
Published: January 2007

MicroRNAs (miRNAs) negatively regulate partially complementary target messenger RNAs. Target selection in animals is dictated primarily by sequences at the miRNA 5′ end. We demonstrated that despite their small size, specific miRNAs contain additional sequence elements that control their posttranscriptional behavior, including their subcellular localization. We showed that human miR-29b, in contrast to other studied animal miRNAs, is predominantly localized to the nucleus. The distinctive hexanucleotide terminal motif of miR-29b acts as a transferable nuclear localization element that directs nuclear enrichment of miRNAs or small interfering RNAs to which it is attached. Our results indicate that miRNAs sharing common 5′ sequences, considered to be largely redundant, might have distinct functions because of the influence of cis-acting regulatory motifs.
The Very-High-Energy Gamma-Ray Sky
Authors: Aharonian Felix
Published: January 2007

Over the past few years, very-high-energy gamma-ray astronomy has emerged as a truly observational discipline, with many detected sources representing different galactic and extragalactic source populations—supernova remnants, pulsar wind nebulae, giant molecular clouds, star formation regions, compact binary systems, and active galactic nuclei. It is expected that observations with the next generation of stereoscopic arrays of imaging atmospheric Cherenkov telescopes over a very broad energy range from 10
10
to 10
15
electron volts will dramatically increase the number of very-high-energy gamma-ray sources, thus having a huge impact on the development of astrophysics, cosmology, and particle astrophysics.
Neutrino Astrophysics: A New Tool for Exploring the Universe
Authors: Waxman Eli
Published: January 2007

In the past four decades a new type of astronomy has emerged, where instead of looking up into the sky, “telescopes” are buried miles underground or deep under water or ice and search not for photons (that is, light), but rather for particles called neutrinos. Neutrinos are nearly massless particles that interact very weakly with matter. The detection of neutrinos emitted by the Sun and by a nearby supernova provided direct tests of the theory of stellar evolution and led to modifications of the standard model describing the properties of elementary particles. At present, several very large neutrino detectors are being constructed, aiming at the detection of the most powerful sources of energy and particles in the universe. The hope is that the detection of neutrinos from these sources, which are extra-Galactic and are most likely powered by mass accretion onto black holes, will not only allow study of the sources, but, much like solar neutrinos, will also provide new information about fundamental properties of matter.
LEIBNIZ SUPERALGEBRAS AND CENTRAL EXTENSIONS
Authors: LIU DONG , HU NAIHONG
Published: January 2007

In this paper we study Leibniz superalgebras and their universal central extensions, and obtain some similar results as in the case of Lie superalgebras. We determine universal central extensions of basic classical Lie superalgebras in the category of Leibniz superalgebras. They play a key role in studying Leibniz superalgebras graded by finite root systems.
A defect in glucose-induced dissociation of glucokinase from the regulatory protein in Zucker diabetic fatty rats in the early stage of diabetes
Authors: Shin Jun-Seop , Torres Tracy P. , Catlin ReEtta L. , Donahue E. P. , Shiota Masakazu
Published: January 2007

Effect of stimulation of glucokinase (GK) export from the nucleus by small amounts of sorbitol on hepatic glucose flux in response to elevated plasma glucose was examined in 6-h fasted Zucker diabetic fatty rats at 10 wk of age. Under basal conditions, plasma glucose, insulin, and glucagon were ∼8 mM, 2,000 pmol/l, and 60 ng/l, respectively. Endogenous glucose production (EGP) was 44 ± 4 μmol·kg−1·min−1. When plasma glucose was raised to ∼17 mM, GK was still predominantly localized with its inhibitory protein in the nucleus. EGP was not suppressed. When sorbitol was infused at 5.6 and 16.7 μmol·kg−1·min−1, along with the increase in plasma glucose, GK was exported to the cytoplasm. EGP (23 ± 19 and 12 ± 5 μmol·kg−1·min−1) was suppressed without a decrease in glucose 6-phosphatase flux (145 ± 23 and 126 ± 16 vs. 122 ± 10 μmol·kg−1·min−1without sorbitol) but increased in glucose phosphorylation as indicated by increases in glucose recycling (122 ± 17 and 114 ± 19 vs. 71 ± 11 μmol·kg−1·min−1), glucose-6-phosphate content (254 ± 32 and 260 ± 35 vs. 188 ± 20 nmol/g liver), fractional contribution of plasma glucose to uridine 5′-diphosphate-glucose flux (43 ± 8 and 42 ± 8 vs. 27 ± 6%), and glycogen synthesis from plasma glucose (20 ± 4 and 22 ± 5 vs. 9 ± 4 μmol glucose/g liver). The decreased glucose effectiveness to suppress EGP and stimulate hepatic glucose uptake may result from failure of the sugar to activate GK by stimulating the translocation of the enzyme.
Effects of maternal parity and late gestational nutrition on mRNA abundance for growth factors in the liver of postnatal sheep
Authors: Hyatt Melanie A. , Budge Helen , Walker David , Stephenson Terence , Symonds Michael E.
Published: January 2007

The liver is a major metabolic and endocrine organ in growing neonates, but the extent to which its hormone receptor (R) sensitivity is potentially determined by maternal parity and the mother's nutritional environment is unknown. This was therefore investigated by sampling livers from postnatal sheep born to nulliparous or multiparous mothers. Offspring were sampled 1 or 30 days after birth from mothers consuming either 100 or 50% [i.e., nutrient-restricted (NR) group] of total metabolizable energy requirements from 110 days gestation to term (∼147 days). Regardless of maternal diet, offspring of nulliparous mothers were lighter at birth and had smaller livers. By 1 mo of age, they exhibited catch-up growth, an adaptation not seen when mothers were NR, but they retained their lighter livers. At both sampling ages, livers from offspring born to nulliparous mothers exhibited increased mRNA abundance for growth hormone (GH) receptor, IGF-IR, plus hepatocyte growth factor (HGF); and at day 1 only IGF-I, but not IGF-IIR mRNA was decreased. In addition, mRNA for IGF-II, the HGFR, c-Met, and Bax were persistently reduced in these offspring. Effects of parity were largely unaffected by maternal nutrient restriction. Maternal parity therefore has a substantial effect on liver size during postnatal development and its receptor population that is not dependent on maternal diet. First-born offspring appear to exhibit a resetting of the endocrine control of hepatic growth within the HGF and GH-IGF axis, which could have later consequences after their growth has caught up.
V-H+-ATPase translocation during blood alkalosis in dogfish gills: interaction with carbonic anhydrase and involvement in the postfeeding alkaline tide
Authors: Tresguerres Martin , Parks Scott K. , Wood Chris M. , Goss Greg G.
Published: January 2007

We investigated the involvement of carbonic anhydrase (CA) in mediating V-H+-ATPase translocation into the basolateral membrane in gills of alkalotic Squalus acanthias. Immunolabeling revealed that CA is localized in the same cells as V-H+-ATPase. Blood plasma from dogfish injected with acetazolamide [30 mg/kg at time ( t) = 0 and 6 h] and infused with NaHCO3for 12 h (1,000 μeq·kg−1·h−1) had significantly higher plasma HCO3−concentration than fish that were infused with NaHCO3alone (28.72 ± 0.41 vs. 6.57 ± 2.47 mmol/l, n = 3), whereas blood pH was similar in both treatments (8.03 ± 0.11 vs. 8.04 ± 0.11 pH units at t = 12 h). CA inhibition impaired V-H+-ATPase translocation into the basolateral membrane, as estimated from immunolabeled gill sections and Western blotting on gill cell membranes (0.24 ± 0.08 vs. 1.00 ± 0.28 arbitrary units, n = 3; P < 0.05). We investigated V-H+-ATPase translocation during a postfeeding alkalosis (“alkaline tide”). Gill samples were taken 24–26 h after dogfish were fed to satiety in a natural-like feeding regime. Immunolabeled gill sections revealed that V-H+-ATPase translocated to the basolateral membrane in the postfed fish. Confirming this result, V-H+-ATPase abundance was twofold higher in gill cell membranes of the postfed fish than in fasted fish ( n = 4–5; P < 0.05). These results indicate that 1) intracellular H+or HCO3−produced by CA (and not blood pH or HCO3−) is likely the stimulus that triggers the V-H+-ATPase translocation into the basolateral membrane in alkalotic fish and 2) V-H+-ATPase translocation is important for enhanced HCO3−secretion during a naturally occurring postfeeding alkalosis.
Stem Cell Factor Attenuates Vascular Smooth Muscle Apoptosis and Increases Intimal Hyperplasia After Vascular Injury
Authors: Wang Chao-Hung , Verma Subodh , Hsieh I-Chang , Hung Agnes , Cheng Ting-Tzu , Wang Shin-Yi , Liu Yu-Chih , Stanford William L. , Weisel Richard D. , Li Ren-Ke , Cherng Wen-Jin
Published: January 2007

Objective—

Stem cell factor (SCF) through its cognate receptor, the tyrosine kinase
c-kit
, promotes survival and biological functions of hematopoietic stem cells and progenitors. However, whether SCF/
c-kit
interactions exacerbate intimal hyperplasia through attenuating VSMC apoptosis induced by vascular injury has not been thoroughly investigated.

Methods and Results—

VSMCs were stimulated with serum deprivation and H
2
O
2
to induce apoptosis. The transcription of
c-kit
mRNA and the expression of the
c-kit
protein by VSMCs were estimated by Q-polymerase chain reaction and Western blotting, respectively. The interactions of SCF and
c-kit
were investigated by in vitro and in vivo experiments. In vitro, H
2
O
2
stimulation significantly induced apoptosis of VSMCs as evidenced by the 3- and 3.2-fold increases of cleaved caspase-3 compared with those in the control group by Western blot and flow cytometric analyses, respectively (
P
<0.01). Stimulation of apoptosis also caused 3.5- and 9-fold increases in
c-kit
mRNA transcription and protein expression, respectively, by VSMCs compared with those in the control group. Administration of SCF (10 to 1000 ng/mL) significantly lowered the amount of cleaved caspase-3 in H
2
O
2
-treated VSMCs (
P
<0.01). Specifically, SCF exerted this effect through activating Akt, followed by increasing Bcl-2 and then inhibiting the release of cytochrome-c from the mitochondria to the cytosol. In vivo, the mouse femoral artery was injured with a wire in SCF mutant (

Sl/Sl
d

), c-
kit
mutant (

W/W
v

), and colony control mice. In colony control mice, confocal microscopy demonstrated that the wire-injury generated a remarkable activation of caspase-3 on medial VSMCs, coinciding with upregulation of c-
kit
expression. The wire-injury also caused an increase in the expression of SCF on surviving medial VSMCs and cells in the adventitia. The upregulated
c-kit
expression in the vessel wall also facilitated homing by circulating SCF
+
cells. Compared with colony control mice, vascular injury in SCF mutant and c-
kit
mutant mice caused a higher number of apoptotic VSMCs on day 14 and a lower number of proliferating cells, and resulted in significantly less neointimal formation (
P
<0.01) on day 28.

Conclusions—

The interactions between SCF and the c-
kit
receptor play an important role in protecting VSMCs against apoptosis and in maintaining intimal hyperplasia after vascular injury.
The Thr715Pro Polymorphism of the P-Selectin Gene Is Not Associated With Ischemic Stroke Risk
Authors: Ferrari Julia , Rieger Sandra , Endler Georg , Greisenegger Stefan , Funk Marion , Scholze Thomas , Lang Wilfried , Lalouschek Wolfgang , Mannhalter Christine
Published: January 2007

Background and Purpose—

A Thr>Pro polymorphism at codon 715 in the coding region of the P-selectin gene has recently been described. Individuals carrying the Pro715 allele were reported to have a reduced risk of myocardial infarction. A possible association of this polymorphism with the risk of ischemic stroke is currently under discussion.

Methods—

We investigated the prevalence of the 715 Thr>Pro polymorphism in 450 patients aged younger than 60 years with ischemic stroke or transient ischemic attack and in 450 controls without vascular disease matched for age and gender. We also investigated possible interactions of the polymorphism with other vascular risk factors, stroke severity and stroke etiology.

Results—

The distribution of the two allelic variants of the 715Thr>Pro polymorphism did not differ significantly between patients and control subjects (78% versus 81% for Thr/Thr, 21% versus 18% for Thr/Pro and 1% versus 1% for Pro/Pro in patients and controls, respectively; adjusted odds ratio for carriers of the C allele: 1.0 [0.8 to 1.2;
P
=0.695]). We found no significant interaction of this polymorphism with vascular risk factors, stroke severity, or stroke etiology.

Conclusions—

Our study supports results from previous investigation showing that the 715Thr>Pro polymorphism of the P-selectin gene was not associated with a risk or clinical characteristics of ischemic stroke.
The Astrocyte as a Gatekeeper of Synaptic Information Transfer
Authors: Volman Vladislav , Ben-Jacob Eshel , Levine Herbert
Published: January 2007

We present a simple biophysical model for the coupling between synaptic transmission and the local calcium concentration on an enveloping astrocytic domain. This interaction enables the astrocyte to modulate the information flow from presynaptic to postsynaptic cells in a manner dependent on previous activity at this and other nearby synapses. Our model suggests a novel, testable hypothesis for the spike timing statistics measured for rapidly firing cells in culture experiments.
Boundedness and Stability for Integrodifferential Equations Modeling Neural Field with Time Delay
Authors: Lou Xuyang , Cui Baotong
Published: January 2007

In this letter, delayed integrodifferential equations modeling neural field (DIEMNF) is studied. The model of DIEMNF is first established as a modified neural field model. Second, it has been proved that if the interconnection of neural field is symmetric, then every trajectory of the system converges to an equilibrium. The boundedness condition for integrodifferential equations modeling neural field with delay is obtained. Moreover, when the interconnection is asymmetric, we give a sufficient condition that can guarantee that the equilibrium of the DIEMNF is unique and is also a global attractor.
Recombinant Escherichia coli produces tailor-made biopolyester granules for applications in fluorescence activated cell sorting: functional display of the mouse interleukin-2 and myelin oligodendrocyte glycoprotein
Authors: Bäckström B Thomas , Brockelbank Jane A , Rehm Bernd HA
Published: January 2007

Background

Fluorescence activated cell sorting (FACS) is a powerful technique for the qualitative and quantitative detection of biomolecules used widely in both basic research and clinical diagnostic applications. Beads displaying a specific antigen are used to bind antibodies which are then fluorescently labelled using secondary antibodies. As the individual suspension bead passes through the sensing region of the FACS machine, fluorescent signals are acquired and analysed. Currently, antigens are tediously purified and chemically cross-linked to preformed beads. Purification and coupling of proteins often renders them inactive and they will not be displayed in its native configuration. As an alternative, we genetically engineeredEscherichia colito produce biopolyester (polyhdroxyalkanoate=PHA) granules displaying diagnostically relevant antigens in their native conformation and suitable for FACS analysis.

Results

Hybrid genes were constructed, which encode either the mouse interleukin-2 (IL2) or the myelin oligodendrocyte glycoprotein (MOG) fused via an enterokinase site providing linker region to the C terminus of the PHA granule associated protein PhaP, respectively. The hybrid genes were expressed in PHA-accumulating recombinantE. coli. MOG and IL2 fusion proteins were abundantly attached to PHA granules and were identified by MALDI-TOF/MS analysis and N terminal sequencing. A more abundant second fusion protein of either MOG or IL2 resulted from an additional N terminal fusion, which did surprisingly not interfere with attachment to PHA granule. PHA granules displaying either IL2 or MOG were used for FACS using monoclonal anti-IL2 or anti-MOG antibodies conjugated to a fluorescent dye. FACS analysis showed significant and specific binding of respective antibodies. Enterokinase treatment of IL2 displaying PHA granules enabled removal of IL2 as monitored by FACS analysis. Mice were immunized with either MOG or OVA (ovalbumin) and the respective sera were analysed using MOG-displaying PHA granules and FACS analysis showing a specific and sensitive detection of antigen-specific antibodies within a wide dynamic range.

Conclusion

E. colican be genetically engineered to produce PHA granules displaying correctly folded eukaryotic proteins and which can be applied as beads in FACS based diagnostics. Since PHA granule formation and protein attachment occurs in one step already inside the bacterial cell, microbial production could be a cheap and efficient alternative to commercial beads.
Midkine Is an Autocrine Activator of Signal Transducer and Activator of Transcription 3 in 3T3-L1 Cells
Authors: Cernkovich Erin R. , Deng Jianbei , Hua Kunjie , Harp Joyce B.
Published: January 2007

Mitotic clonal expansion is believed to be necessary for 3T3-L1 adipocyte formation. Signal transducer and activator of transcription 3 (STAT3), a mitogenic signaling protein, is activated through tyrosine phosphorylation during the proliferative phases of adipogenesis. We hypothesize that this signaling protein plays a key role in mitotic clonal expansion and differentiation. Here we determined that the adipocyte differentiation cocktail containing isobutylmethylxanthine, dexamethasone, and insulin (MDI) induced STAT3 tyrosine phosphorylation indirectly through the synthesis of an autocrine/paracrine factor. We further determined that the factor has heparin binding properties and identified the factor as midkine, a pleiotrophic growth factor previously associated with neuronal development and oncogenesis. Recombinant midkine induced STAT3 tyrosine phosphorylation in a time- and dose-dependent manner and stimulated the proliferation of postconfluent 3T3-L1 cells. Midkine neutralizing antibodies inhibited differentiation-induced STAT3 tyrosine phosphorylation as well as adipogenesis. These results show that MDI-induced synthesis and release of midkine explains the delayed activation of STAT3 during adipogenesis and that the midkine-STAT3 signaling pathway plays a necessary role in mitotic clonal expansion and differentiation.
Distinctly Different Conformations of an Amorphous Polymer with Azobenzene Side Chains in Solid and Solution
Authors: Ichimura Kunihiro , Akiyama Haruhisa
Published: January 2007

A differential scanning calorimetry of a polymethacrylate with azobenzene side chains at the first heating exhibited a scan different from the subsequent ones. Comparison of absorption spectra in an aqueous dispersion, a cast film and dilute solutions of mixtures of dioxane and isopropyl alcohol revealed that the azobenzene forms J-aggregates in polymer solid resulting in the first heating scan whereas the subsequent heating scans corresponds to a polymer conformation with monomeric side chains.
Source Rocks and Petroleum Reservoirs in the Chexi Sunken of the Jiyang Depression, China
Authors: Sun Jianping , Zhang Hongjian , Lin Chunyan
Published: January 2007

In order to study the formation of petroleum and to find petroleum reservoirs, 500 samples were taken from the Chexi Sunken, Jiyang Depression, northern China. These samples were analysed by microscopical and organic geochemical methods. The results indicate that the main source rocks were present in the Shahe formation (ES), Paleogene. The important source rock is within the ES3 formation. Further geological study indicates that the hydrocarbon generation and expulsion occurred mainly in the Neogene. Most reservoirs are present below the ES3 formation.
Deterioration of FRP-to-Concrete Bond under Failure Loading
Authors: Harries Kent A. , Aidoo John , Zorn Andrew , Quattlebaum Joshua
Published: January 2007

Characteristics of FRP-to-concrete bond are observed to deteriorate under cyclic loads. Deterioration has been observed under load conditions which result in a stress range in the bonded FRP of only 4% of the material capacity. Current design recommendations and “accepted practice” often neglect this detrimental effect. The clear effects of bond deterioration under fatigue loading are demonstrated for moderate-scale laboratory specimens and in full-scale specimens recovered from a forty-year old interstate highway bridge. The results suggest additional limit states that must be considered when even relatively small fatigue loads are present.
Does Laboratory Testing Have Predictive and Practical Value for Cycling Performance?
Authors: MacRae Holden S-H.
Published: January 2007

Athletes spend very little of their training time in the laboratory, yet, laboratory measures of performance can significantly affect a coaches' decision as to how the athlete will be trained. When athletes train in preparation for competition, and when competing, are measures of physiological function in the field the same as what is observed in the laboratory, and do the measures of laboratory performance on an athlete have predictive value for training or competition outside of the laboratory? Markers that have historically been used to determine successful cycling performance are maximal aerobic capacity (V̇DO2max), the ability to exercise at a high percentage of V̇DO2max (% V̇DO2max), cycling economy / efficiency, and a variety of “threshold” measures. “Threshold” measures are unlikely to be useful for predicting successful, high-intensity endurance cycling performance, but tracking of changes in V̇DO2max, %V̇DO2max, peak power output (PPO) and cycling economy/efficiency are useful laboratory measures that successfully predict successful field cycling performance Monitoring heart rate during training and competition may be the more important measure since it potentially reflects the regulation of a central brain controller.
A Theoretical Basis of Monitoring Fatigue: A Practical Approach for Coaches
Authors: Lambert Michael , Borresen Jill
Published: January 2007

Training can be described as a process that induces biological adaptations The basic principle of training is that training (breakdown) is followed by rest (recovery) which results in an improvement in performance. An imbalance in the training load and recovery time can result in symptoms of fatigue. If the imbalance between training and rest persists, the athlete may develop serious symptoms of fatigue that will affect the ability to sustain a high training volume and will have a negative effect on performance. While it is important for a coach to have a training plan, it is also important to be able to adjust the plan based on how the athlete is adapting. A coach needs to be able to answer a series of questions in order to make decisions about training prescription. Information to assist the coach in answering these questions can be acquired from various measurements including perception of effort, session RPE, recovery scales, Profile of Mood States (POMS), Daily Analysis of Life Demands for Athletes (DALDA), assessment of muscle soreness and recovery heart rate. This information can guide decision-making about training and reduce the risk of under or overtraining.
Should We Allow Performance-Enhancing Drugs in Sport? A Rebuttal to the Article by Savulescu and Colleagues
Authors: Noakes Timothy D.
Published: January 2007

Savulescu et al. [1] propose that, since it will never be possible to control drug use in sport, athletes should be allowed to use those performance-enhancing drugs that are “safe”. The authors fail to explain, however, why appropriate doping control has yet to be achieved in world sport. In this rebuttal, it is argued that the widespread doping of elite athletes, as is now common, cannot easily occur without government collusion that is either overt or covert. There is also evidence that a number of international sporting bodies have followed the same principle. Furthermore, since their products are so readily available to elite athletes, those pharmaceutical companies that manufacture the most popular performance-enhancing drugs would appear to be indifferent to the misuse of their products by athletes for nonmedical purposes. The control of drug use in sport has never been achieved, because these three stakeholders who should have acted to eliminate doping in sport appear to have chosen an opposite action without due consideration for their ethical responsibility to protect athletes from the proven dangers of doping. Doping in sport can only ever be defended for exclusively commercial reasons (both legal and criminal) and certainly not on the illusory ethical grounds proposed by Savulescu et al. [1].