bluuebunny/crossref_metadata_2025_split huggingface dataset:
Competitive Inhibition of Amino Acid Uptake Suppresses Chlamydial Growth: Involvement of the Chlamydial Amino Acid Transporter BrnQ
Authors: Braun Peter R. , Al-Younes Hesham , Gussmann Joscha , Klein Jeannette , Schneider Erwin , Meyer Thomas F. 
Published: November 2007

ABSTRACTChlamydiaceaeare obligate intracellular bacterial pathogens that strictly depend on host metabolites, such as nucleotides, lipids, and amino acids. Depletion of amino acids in cell culture media results in abnormal chlamydial development in vitro. Surprisingly, enrichment of certain amino acids also retards chlamydial growth. Our experiments revealed that the antichlamydial effects are largely independent of changes in the host cell transcriptome or proteome and in the major signal transduction pathway modulated by amino acids, the mTOR (mammalian target of rapamycin) pathway. Furthermore, the chlamydial growth inhibition induced by leucine, isoleucine, methionine, or phenylalanine was completely reversed by concomitant addition of valine. In contrast, the growth inhibition induced by serine, glycine, or threonine was not reversed by valine addition. Functional characterization of the only predicted chlamydial transporter for branched-chain amino acids, BrnQ, revealed that it can be blocked by leucine, isoleucine, methionine, or phenylalanine but not by serine, glycine, or threonine. This chlamydial transporter is the only known BrnQ homolog possessing specificity for methionine, suggesting a unique strategy for methionine uptake among gram-negative bacteria. The antichlamydial effects of leucine, isoleucine, methionine, and phenylalanine could be explained as competitive inhibition of the BrnQ transporter and subsequent valine starvation.
Penicillin-Binding Proteins and Cell Wall Composition in β-Lactam-Sensitive and -Resistant Strains of
Staphylococcus sciuri
Authors: Zhou Yanjiao , Antignac Aude , Wu Shang Wei , Tomasz Alexander 
Published: November 2007

ABSTRACT

A close homologue of the acquired
Staphylococcus aureus mecA
gene is present as a native gene in
Staphylococcus sciuri
. We determined the patterns of penicillin-binding proteins (PBPs) and the peptidoglycan compositions of several
S. sciuri
strains to explore the functions of this
mecA
homologue, named
pbpD
, in its native
S. sciuri
environment. The protein product of
pbpD
was identified as PBP4 with a molecular mass of 84 kDa, one of the six PBPs present in representatives of each of three subspecies of
S. sciuri
examined. PBP4 had a low affinity for nafcillin, reacted with a monoclonal antibody raised against
S. aureus
PBP2A, and was greatly overproduced in oxacillin-resistant clinical isolate
S. sciuri
SS37 and to a lesser extent in resistant laboratory mutant K1M200. An additional PBP inducible by oxacillin and corresponding to
S. aureus
PBP2A was identified in another oxacillin-resistant clinical isolate,
S. sciuri
K3, which harbors an
S. aureus
copy of
mecA
. Oxacillin resistance depended on the overtranscribed
S. sciuri pbpD
gene in strains SS37 and K1M200, while the resistance of strain K3 depended on the
S. aureus
copy of
mecA
. Our data provide evidence that both
S. aureus mecA
and
S. sciuri pbpD
can function as resistance determinants in either an
S. aureus
or an
S. sciuri
background and that the protein products of these genes,
S. aureus
PBP2A and
S. sciuri
PBP4, can participate in the biosynthesis of peptidoglycan, the muropeptide composition of which depends on the bacterium “hosting” the resistance gene.
Palaeogeothermal response and record of Late Mesozoic lithospheric thinning in the eastern North China Craton
Authors: Hu S. , Fu M. , Yang S. , Yuan Y. , Wang J. 
Published: November 2007

Abstract

The palaeotemperature recorded by vitrinite reflectance (
R
o
) in the pre-Cenozoic uplifted stratigraphic strata, and in Palaeozoic–Mesozoic remnant basins outside the Cenozoic depocentres, has not been overprinted by later thermal events in the eastern North China Craton (NCC). Based on downhole
R
o
data from the Palaeozoic and the Mesozoic subsections, we reconstruct the temperature gradients when the subsections reached their maximum palaeotemperatures in the Middle Triassic and the Cretaceous, and calculate the corresponding heat flow histories since the early Mesozoic. The temperature gradient and heat flow were much higher in the Cretaceous (35–43 °C km
−1
and 73–83 mW m
−2
, respectively) than in the Middle Triassic and at the present. The high palaeo-heat flow during the Late Mesozoic implies that the thickness of the ‘thermal’ lithosphere at that time was
c
. 65 km, about half the thickness of
c
. 135 km estimated for the Early Mesozoic. The change from a stable thermal regime to an active thermal regime took place during the Late Jurassic–Early Cretaceous (
c
. 110 Ma). This tectonothermal event was accompanied by extensive surface erosion, and is also evidenced in the areas adjacent to the NCC, such as the South Yellow Sea and East China Sea basins. Our study provides not only geothermal evidence for the Late Mesozoic lithospheric thinning, but also additional constraints on the thinning mechanism, which is currently being debated.
Fluid evolution and large-scale gold metallogeny during Mesozoic tectonic transition in the Jiaodong Peninsula, eastern China
Authors: Fan H.-R. , Hu F.-F. , Yang J.-H. , Zhai M.-G. 
Published: November 2007

Abstract

The Jiaodong Peninsula or eastern Shandong Province, the most important gold producing in region China, is located in the southeastern margin of the North China Craton. The gold deposits in the Jiaodong Peninsula are divided into three gold belts, from west to east, the Zhaoyuan–Laizhou, Penglai–Qixia and Muping–Rushan belts. The deposits occur as gold-bearing quartz veins and disseminated- and stockwork-style ores adjacent to fault zones. Most of the gold deposits can be classified in four stages: stage I, quartz–(minor) pyrite; stage II, pyrite–quartz–gold; stage III, quartz–base metal sulphide minerals; stage IV, quartz–carbonate. Ar–Ar ages, Rb–Sr isochrons, and hydrothermal zircon sensitive high-resolution ion microprobe U–Pb ages obtained from these deposits suggest a gold mineralization time of 120±10 Ma. The Sr–Nd isotopic compositions of pyrites and the associated rocks suggest that the ore-forming materials were probably derived from a mixed source. Fluid inclusion studies show that ore-forming fluids of gold deposits are consistent throughout the Jiaodong Peninsula, with similar mineralizing temperature and pressure conditions. Ore-forming fluids are characterized by H
2
O–CO
2
–NaCl±CH
4
. The optimal mineralizing temperature and pressure ranges are 170–335 °C and 0.7–2.5 kbar. Oxygen and hydrogen isotope data show that ore fluids are of magmatic origin. Gold deposits in the Jiaodong Peninsula formed in the same mineralizing–geodynamic conditions, and are related to the Mesozoic tectonic transition in the eastern North China Craton. Gold metallogeny is only one expression of the Mesozoic tectonic transition.
A mechanism for transforming buoyant North Chinese cratonic lithosphere to a denser equivalent for delamination
Authors: Deng J.-F. , Zhou M.-F. , Flower M. F. J. , Su S.-G. , Zhai M.-G. , Liu C. , Zhao G.-C. , Zhao X.-G. , Zhou S. , Wu Z.-W. 
Published: November 2007

Abstract

Two models have been proposed to explain lithospheric thinning of North Chinese cratonic lithosphere: (1) thermal erosion or/and chemical metasomatism, causing the lower part of the lithospheric mantle to be transformed into asthenosphere, a mechanism that implies thinning of relatively buoyant lithosphere; (2) the delamination of lithospheric mantle, in whole or part, along with the lowermost crust, as an effect of their increased densities relative to the underlying asthenosphere. This paper explores possible mechanisms whereby buoyant cratonic lithosphere might be transformed into a denser equivalent susceptible to delamination by the convecting asthenosphere. The Yanshan mobile belt in Eastern China developed in response to a combination of subduction and collision. Its apparent ‘counterclockwise’
P
–
T
–
t
metamorphic evolution suggests that underplated basaltic magma may have heated and, in turn, weakened the cool, rigid crust, allowing for compressional deformation and crustal thickening. Based on three independent lines of evidence (compressional deformation, the record of igneous activity, and lower crustal xenoliths) the thickness of continental crust is estimated to be about 50–65 km. Along with petrological and geochemical studies, thermal modelling shows that large-scale input of asthenospheric basaltic magma leads to granitoid partial melts in the lower crust, and the dominance of high-pressure eclogitic products following orogenic thickening may be necessary for eventual delamination to occur.
Injury Patterns in Professional Arena Football
Authors: Herbenick Michael A. , King Jonathan S. , Altobelli Grant , Nguyen Brian , Podesta Luga 
Published: November 2007

Background No studies to date have evaluated the injury patterns in professional arena football. The purpose of this study is to describe the characteristics of general injury patterns in the Arena Football League. Hypotheses (1) Game injury rates are higher than are practice injury rates, (2) a small number of injuries are related to collision with the boards, and (3) athletes playing on both offense and defense have higher injury rates than do athletes playing either offense or defense alone. Study Design Descriptive epidemiology study. Methods A retrospective review of injury data including 1199 injuries over a 4-year period from February 2002 to December 2005, inclusive of preseason and postseason practices and competition, was conducted. Data regarding the injured body part, position of the player, nature of injury, mechanism of injury, missed playing time, playing surface, and when the injury occurred were collected and analyzed. Results Injury rates during practice were 14.6 injuries per 1000 exposures and game injury rates were 111.3 per 1000 exposures. Few recorded injuries (2.2%) involved a collision with the sideline boards. Conclusion Game injury rates are higher than are practice injury rates. Athletes playing on both offense and defense did not have higher injury rates in games than did athletes playing either offense or defense. The sideline boards used in the Arena Football League did not appear to contribute dramatically to the injury rates. Despite the differences between arena and stadium football, Arena Football League injury patterns are similar to published collegiate football injury patterns.
Inferring biological functions and associated transcriptional regulators using gene set expression coherence analysis
Authors: Kim Tae-Min , Chung Yeun-Jun , Rhyu Mun-Gan , Ho Jung Myeong 
Published: November 2007

AbstractBackgroundGene clustering has been widely used to group genes with similar expression pattern in microarray data analysis. Subsequent enrichment analysis using predefined gene sets can provide clues on which functional themes or regulatory sequence motifs are associated with individual gene clusters. In spite of the potential utility, gene clustering and enrichment analysis have been used in separate platforms, thus, the development of integrative algorithm linking both methods is highly challenging.ResultsIn this study, we propose an algorithm for discovery of molecular functions and elucidation of transcriptional logics using two kinds of gene information, functional and regulatory motif gene sets. The algorithm, termed gene set expression coherence analysis first selects functional gene sets with significantly high expression coherences. Those candidate gene sets are further processed into a number of functionally related themes or functional clusters according to the expression similarities. Each functional cluster is then, investigated for the enrichment of transcriptional regulatory motifs using modified gene set enrichment analysis and regulatory motif gene sets. The method was tested for two publicly available expression profiles representing murine myogenesis and erythropoiesis. For respective profiles, our algorithm identified myocyte- and erythrocyte-related molecular functions, along with the putative transcriptional regulators for the corresponding molecular functions.ConclusionAs an integrative and comprehensive method for the analysis of large-scaled gene expression profiles, our method is able to generate a set of testable hypotheses: the transcriptional regulator X regulates function Y under cellular condition Z. GSECA algorithm is implemented into freely available software package.
Posttraumatic secondary brain insults exacerbates neuronal injury by altering Metabotropic Glutamate Receptors
Authors: Fei Zhou , Zhang Xiang , Bai Hong-min , Jiang Xiao-fan , Li Xia , Zhang Wei , Hu Wei 
Published: November 2007

AbstractBackgroundOur previous studies indicated that metabotropic glutamate receptors (mGluRs) are deeply involved in the secondary processes after diffuse brain injury (DBI). In the present study, we used a rodent DBI model to determine whether hypotension exacerbates neuronal injury as a secondary brain insult (SBI) after traumatic brain injury (TBI) by changing the expression of metabotropic glutamate receptors (mGluRs) in the cerebral cortex.ResultsThree hundred and eleven male Sprague-Dawley rats were randomly assigned into five groups: normal control, sham-operated control, SBI alone, DBI alone, or DBI with SBI. DBI was produced in rats by Marmarou's methods and the SBI model was produced by hypotension. The alteration of neuronal expression of mGluRs after DBI and DBI coupled with SBI was observed by hybridization in situ at different time points in the experiment. We found a higher mortality and neurological severity score (NSS) for rats in the DBI with SBI group compared with those in the DBI alone group. Although there was a significant rise in the expression of group I and group III mGluRs (except mGluR6) and a decrease in the expression of group II mGluRs after DBI (P < 0.05), the changes were more severe when DBI was coupled with SBI (P < 0.05). The expression of group I mGluRs peaked at 24 hours, while the expression of the group III mGluRs peaked at 6 hours after injuries, which may reflect a self-protection first mechanism of the damaged neurons. Moreover, the overall neuro-harmful effects of mGluRs on neurons were seemly associated with higher mortality and NSS in the DBI with SBI group.ConclusionThe results suggest posttraumatic SBI may exacerbate neuronal injury or brain injury by altering expression of mGluRs, and more emphasis should therefore be put on the prevention and treatment of SBI.
The effect of environmental factors on technical and scale efficiency of primary health care providers in Greece
Authors: Kontodimopoulos Nick , Moschovakis Giorgos , Aletras Vassilis H , Niakas Dimitris 
Published: November 2007

Abstract

Background
The purpose of this study was to compare technical and scale efficiency of primary care centers from the two largest Greek providers, the National Health System (NHS) and the Social Security Foundation (IKA) and to determine if, and how, efficiency is affected by various exogenous factors such as catchment population and location.

Methods
The sample comprised of 194 units (103 NHS and 91 IKA). Efficiency was measured with Data Envelopment Analysis (DEA) using three inputs, -medical staff, nursing/paramedical staff, administrative/other staff- and two outputs, which were the aggregated numbers of scheduled/emergency patient visits and imaging/laboratory diagnostic tests. Facilities were categorized as small, medium and large (<15,000, 15,000–30,000 and >30,000 respectively) to reflect catchment population and as urban/semi-urban or remote/island to reflect location. In a second stage analysis, technical and scale efficiency scores were regressed against facility type (NHS or IKA), size and location using multivariate Tobit regression.

Results
Regarding technical efficiency, IKA performed better than the NHS (84.9% vs. 70.1%, Mann-Whitney P < 0.001), smaller units better than medium-sized and larger ones (84.2% vs. 72.4% vs. 74.3%, Kruskal-Wallis P < 0.01) and remote/island units better than urban centers (81.1% vs. 75.7%, Mann-Whitney P = 0.103). As for scale efficiency, IKA again outperformed the NHS (89.7% vs. 85.9%, Mann-Whitney P = 0.080), but results were reversed in respect to facility size and location. Specifically, larger units performed better (96.3% vs. 90.9% vs. 75.9%, Kruskal-Wallis P < 0.001), and urban units showed higher scale efficiency than remote ones (91.9% vs. 75.3%, Mann-Whitney P < 0.001). Interestingly 75% of facilities appeared to be functioning under increasing returns to scale. Within-group comparisons revealed significant efficiency differences between the two primary care providers. Tobit regression models showed that facility type, size and location were significant explanatory variables of technical and scale efficiency.

Conclusion
Variations appeared to exist in the productive performance of the NHS and IKA as the two main primary care providers in Greece. These variations reflect differences in primary care organization, economical incentives, financial constraints, sociodemographic and local peculiarities. In all technical efficiency comparisons, IKA facilities appeared to outperform NHS ones irrespective of facility size or location. In respect to scale efficiency, the results were to some extent inconclusive and observed differences were mostly insignificant, although again IKA appeared to perform better.
Burn-induced immunosuppression: attenuated T cell signaling independent of IFN-γ- and nitric oxide-mediated pathways
Authors: Duan Xunbao , Yarmush David , Leeder Avrum , Yarmush Martin L , Mitchell Richard N 
Published: November 2007

AbstractBurn injury results in immunosuppression; previous work implicated a combination of altered T lymphocyte subpopulations and the elaboration of macrophage-derived mediators. However, the conclusions were based on T cell stimulations in the setting of high-dose polyclonal mitogenic stimuli and a single kinetic time-point. In this study, splenocytes from burned animals were used to examine lymphocyte responses over a multi-day time course following saturating and subsaturating anti-CD3, as well as mixed lymphocyte response (MLR) stimulation. Burn injury resulted in suppressed splenocyte-proliferative responses to high-dose anti-CD3 (2 μg/ml) at all culture time-points (Days 2–5); this inhibition was eliminated by removing macrophages from the splenocyte cultures, by blocking NO production, or by using splenocytes from burned animals congenitally deficient in IFN-γ (IFN-γ−/−). The results are consistent with immunosuppression attributable to burn-induced IFN-γ production, which in turn, drives macrophage NO synthesis (NOS). In MLR cultures, lymphocyte proliferation and IFN-γ production were depressed at later time-points (Days 3–5). APC from burned animals showed no defects as MLR stimulators; T cells from burned animals showed defective, proliferative responses, regardless of the stimulator population. Removing macrophages, adding a NOS inhibitor, or using IFN-γ−/− splenocytes did not restore the MLR response of burned splenocytes. T cells from burned IFN-γ−/− animals also showed depressed proliferation with subsaturating levels of anti-CD3 (0.1 μg/ml); anti-CD-28 augmented the proliferative response. We conclude that burn-induced immunosuppression to authentic antigenic stimulation is related at least in part to defective CD3 signaling pathways and not simply to increased IFN-γ or NO production.
The Structural Comparison of Social Policy and Intergovernmental Politics
Authors: Ashford Douglas E. 
Published: November 2007

Although the development of states providing a wide variety of social services is perhaps the distinguishing feature of modem democratic governance, the available theories of the political transformation inherent in this intricate metamorphosis remain inadequate. Without carefully specifying the requirements of such a theory, it is unlikely that we shall devise one. In this respect, this article is an exercise in what might somewhat pretentiously be called metatheory, that is, it asks what are the characteristics of the problem we wish to study and what are the prerequisites of building a theory that might account for this transformation. Though the list might be extended, three analytical problems confront any developmental theory having claim to comparative validity: first, we need an historical or longitudinal dimension; second, we must remain sensitive to the ease with which causal relationships among social policies can reverse; and, third, there must be a workable or empirical foundation by which we may refute hypotheses drawn from the theory.
Putting aside global theories derived from particular, and often overdetermined, views of history, it is important to see that what is required is a structural theory.
The Political Economy of Employee Investment Funds
Authors: Burkitt Brian 
Published: November 2007

‘No man is good enough to be another man’s master’ (William Morris).
Economists frequently describe efficiency and equality as two separate, yet potentially conflicting, objectives. While in some circumstances the achievement of one of these objectives might preclude attaining the other, the evidence suggests that the post-war British economy has suffered a decline in relative efficiency with no progress towards greater equality. Faster growth rates, full employment and higher living standards are most likely to occur as a result of increased and sustained capital formation. The currently dominant economic philosophy of monetarism seeks to satisfy this requirement by redistributing income towards capitalists in the hope that they will then find investment attractive. The British left urgently requires an alternative strategy that generates new investment, while simultaneously establishing an ongoing egalitarian trend. As the political conditions for a revolutionary transformation of society are unlikely to prevail in the foreseeable future, socialist governments need to fulfil three crucial economic objectives:-

(i) to restore full employment while maintaining approximate price stability,
(ii) to accelerate the rate of capital accumulation in order to boost future increases in living standards,
(iii) to redistribute income and wealth in the direction of greater equality without imperilling future economic growth.
The Youth Guarantee in Scandinavia
Authors: Jackson Michael P. 
Published: November 2007

The idea of a youth guarantee was discussed in a number of Scandinavian countries in the mid 1970s. In Sweden the idea of an ‘education or employment guarantee’ was raised in a bill put to Parliament by the People’s Party in 1975. At the same time similar ideas were being put forward by other bodies including the Central Party and the Moderate Coalition Party. In 1976 the municipalities were given the responsibility of following the progress of young people under the age of 18 and the Education Ordinance made it clear that the aim was to give young people ‘an opportunity for employment, work experience or training/education’ (National Swedish Board of Education, 1982, p1).
In Norway a youth guarantee was discussed by a committee examining the problems facing young people in a report issued in 1976. The following year the government put forward a ‘youth guarantee’ as a policy objective. In a paper laid before the Norwegian Parliament the government argued that society has a formal responsibility for the transitional phase between education and employment: