bluuebunny/crossref_metadata_2025_split huggingface dataset:
FeO‐rich rims and veins in Allende forsterite: Evidence for high temperature condensation at oxidizing conditions
Authors: Weinbruch S. , Palme H. , Müller W. F. , El Goresy A. 
Published: June 2012

Abstract— Forsteritic olivine grains in the Allende meteorite are commonly rimmed by FeO‐rich olivine. New evidence is presented in this paper that the fayalitic rims formed by condensation from a gas and not by thermal equilibration of forsterite with FeO‐rich metal or FeO‐rich olivine in the interior of a parent body. A similar origin is inferred for fayalitic veins within forsterite crystals.A good correlation of FeO with MnO was observed along profiles from forsteritic cores to fayalite‐rich rims, excluding oxidation of metal as a source of rim FeO. The fayalite content of the rim is generally lower than that of the adjacent matrix olivines excluding formation of FeO‐rich rims by equilibration with present matrix. This is also supported by systematic differences in Cr between rim and matrix olivines.Chromites, associated with FeO‐rich olivine, were found at the boundary between forsterite and fayalite‐rich rim, within the rim itself and in fayalitic veins. Condensation of chromite from a gas phase is likely for the latter two occurrences since no other suitable source of Cr is available. Chromite at the forsterite‐fayalite interface was formed by diffusion of Cr from forsterite. Increasingly oxidizing conditions, apparently enabled formation of chromite.The steep compositional gradient between forsterite and fayalite provides severe constraints on the thermal history of forsterite grains. The width of oxidized zones (halos) around metal inclusions in the interior of forsterite grains are not compatible with this steep gradient. Their development requires longer diffusion times than would be allowed by the rims, indicating that these forsterite grains must have had an independent history of oxidation prior to formation of the rim.Condensation calculations indicate that FeO‐rich olivine can be formed by condensation from a gas with enhanced oxygen fugacity. Increasing the oxygen fugacity would provide conditions allowing the thermodynamic stability of chromite.High temperatures and oxidizing conditions must have prevailed for some time in that part of the solar nebula where the Allende meteorite formed.
Implications for cratering mechanics from a study of the Footwall Breccia of the Sudbury impact structure, Canada
Authors: Lakomy R. 
Published: June 2012

Abstract— The Footwall Breccia layer in the North Range of the Sudbury impact structure is up to 150 m thick. It has been analyzed for several aspects: shock metamorphism of clasts, matrix texture, mineralogy, and geochemistry with respect to major and trace element compositions. The matrix of this heterolithic breccia contains mineral and lithic fragments, which have suffered shock pressures exceeding 10 GPa, along with clasts of breccia dikes originating from the crater basement. The matrix in a zone near the upper contact of the breccia layer is dominated by a dioritic composition with intersertal textures, whereas beneath this zone the matrix is characterized by poikilitic to granular textures and a tonalitic to granitic composition. Major and trace element analyses of adjacent slices of a thin‐slab profile from the breccia show that the matrix is chemically inhomogeneous within a range of 3 mm. The breccia layer has been thermally annealed by the overlying Sudbury Igneous Complex, which is interpreted as a coherent impact melt sheet. The Rb‐Sr isochron age of 1.825 ± 0.021 Ga for the matrix is a cooling age after partial melting of fine grained clastic material by the melt system. Two‐pyroxene thermometry calculations give temperatures in excess of 1000 °C for this thermal overprinting. Clasts were affected by recrystallization, melting, and reactions with the surrounding matrix at that time. The crystallization of the molten matrix resulted in the observed variety of igneous textures. Results of clast population statistics for the Footwall Breccia along with both geochemical considerations and the Sr‐Nd isotopic signature of the matrix indicate that the breccia constituents exclusively derived from the Levack gneiss complex, which forms the local country rock to the breccia layer in the Levack area. K‐feldspar‐rich domains, which tend to replace parts of matrix and felsic gneiss fragments have been formed due to metasomatic activities during the Penokean orogeny, ∼ 1.7 Ga ago.The available observations suggest that the Sudbury structure represents the remnant of a multi‐ring basin with an apparent diameter between 180 and 200 km and a diameter of the transient cavity of about 100 km. For a crater of the size of the Sudbury basin a maximum depth of excavation of ∼21 km and a depth of shock‐melted target rocks of ∼27 km are obtained. In the Sudbury crater, the Footwall Breccia layer represents a part of the uplifted crater floor directly underlying the thick coherent impact melt sheet.
Cosmic spherules in the geologic record
Authors: Taylor Susan , Brownlee Donald E. 
Published: June 2012

Abstract— Cosmic spherules obtained from the Greenland ice cap, deep‐sea sediments, and ancient oceanic deposits of Eocene and Jurassic age were chemically and texturally compared. The proportions of spherule types were found to change as a function of time, with the number of iron spherules increasing as the age of the sample increased. It is not yet possible, however, to determine if the variation in spherule types represents a real change in the meteoroid complex or is a result of differential weathering of the spherules in the Earth's environment.The age of these spherules ranges from less than 3000 years to about 190 million years. Although only a few spherules older than 500 000 years are chemically unaltered, textural information is available even from the oldest spherules and, by comparison with contemporary spherules, gives some insight into the original compositions of the particles.
The Leonard Medal Address
Authors: Clayton Donald D. 
Published: June 2012

Abstract— The science of nucleosynthesis was substantially inspired by chemical analyses of meteorites. As if in repayment, that theory now imbues meteoritics with enlarged meaning. I recount the emergence of four great issues for nucleosynthesis—issues that received decades of my own attention; and I describe unexpected abundance patterns within meteorites that were suggested by the resolution of those issues. The latter have altered the information content of meteoritic science. The issues are:1. a quantitative s‐process theory2. cosmoradiogenic chronology3. explosive nucleosynthesis and gamma‐ray astronomy4. cosmic chemical memoryStarting from historical origins for each issue, I comment upon both the broad cultural canvas in which they lie and my own work in their establishment. Examples of predicted (or rationalized) meteoritic measurements illustrate our surprised delight at the expansion of the range and power of meteoritic science.
Boron cosmochemistry. Part II: Boron nucleosynthesis and condensation temperature
Authors: Zhai Mingzhe 
Published: June 2012

Abstract— The new B solar‐system abundance calculated by Zhai and Shaw (1994), 16.9 atoms/106 Si (or 606 atoms/1012 H) is used to reevaluate the different possibilities of LiBeB (except 7Li) nucleosynthesis. The revised abundances support two models: (1) Light elements were formed by continual bombardment of interstellar medium (ISM) by galactic cosmic rays (GCRs), but these galactic cosmic rays should contain a very intense low‐energy component, in the form of E−5 which cannot be observed near the Earth due to solar modulation effects; (2) Light elements are a mixture of two sources. In the first source, light elements were synthesized by continual bombardment of interstellar medium by galactic cosmic rays. In the second source, they were made by the interactions of C and O nuclei ejected from supernovae with the H and He in the surrounding gas. The first source constitutes ∼46% of total B.The Si‐normalized and CI‐meteorite‐normalized abundances of common and volatile elements in carbonaceous chondrites show a linear correlation with their condensation temperatures. Using this relationship and the normalized B abundances in CM, CO, and CV meteorites, we can estimate the B condensation temperature to be ∼910 K, which is similar to Ga.
Emergence of Metallo-β-Lactamase GIM-1 in a Clinical Isolate of Serratia marcescens
Authors: Rieber Heime , Frontzek Andre , Pfeifer Yvonne 
Published: June 2012

ABSTRACT

The metallo-β-lactamase GIM-1 (German imipenemase) has been found so far only in clinical isolates of
Pseudomonas aeruginosa
from Germany. Here we report the detection of
bla
GIM-1
in a clinical strain of
Serratia marcescens
that was isolated from urine, blood, and wound samples over a period of 20 months. The strain was repeatedly isolated from one patient in two German hospitals and an outpatient department located in the region in which all previously described GIM-1-producing
P. aeruginosa
strains were identified.
Broadening the Spectrum of β-Lactam Antibiotics through Inhibition of Signal Peptidase Type I
Authors: Therien Alex G. , Huber Joann L. , Wilson Kenneth E. , Beaulieu Patrick , Caron Alexandre , Claveau David , Deschamps Kathleen , Donald Robert G. K. , Galgoci Andrew M. , Gallant Michel , Gu Xin , Kevin Nancy J. , Lafleur Josiane , Leavitt Penny S. , Lebeau-Jacob Christian , Lee Suzy S. , Lin Molly M. , Michels Anna A. , Ogawa Aimie M. , Painter Ronald E. , Parish Craig A. , Park Young-Whan , Benton-Perdomo Liliana , Petcu Mihai , Phillips John W. , Powles Mary Ann , Skorey Kathryn I. , Tam John , Tan Christopher M. , Young Katherine , Wong Simon , Waddell Sherman T. , Miesel Lynn 
Published: June 2012

ABSTRACT

The resistance of methicillin-resistant
Staphylococcus aureus
(MRSA) to all β-lactam classes limits treatment options for serious infections involving this organism. Our goal is to discover new agents that restore the activity of β-lactams against MRSA, an approach that has led to the discovery of two classes of natural product antibiotics, a cyclic depsipeptide (krisynomycin) and a lipoglycopeptide (actinocarbasin), which potentiate the activity of imipenem against MRSA strain COL. We report here that these imipenem synergists are inhibitors of the bacterial type I signal peptidase SpsB, a serine protease that is required for the secretion of proteins that are exported through the Sec and Tat systems. A synthetic derivative of actinocarbasin, M131, synergized with imipenem both
in vitro
and
in vivo
with potent efficacy. The
in vitro
activity of M131 extends to clinical isolates of MRSA but not to a methicillin-sensitive strain. Synergy is restricted to β-lactam antibiotics and is not observed with other antibiotic classes. We propose that the SpsB inhibitors synergize with β-lactams by preventing the signal peptidase-mediated secretion of proteins required for β-lactam resistance. Combinations of SpsB inhibitors and β-lactams may expand the utility of these widely prescribed antibiotics to treat MRSA infections, analogous to β-lactamase inhibitors which restored the utility of this antibiotic class for the treatment of resistant Gram-negative infections.
Social inequality and infant health in the UK: systematic review and meta-analyses
Authors: Weightman Alison L , Morgan Helen E , Shepherd Michael A , Kitcher Hilary , Roberts Chris , Dunstan Frank D 
Published: June 2012

ObjectivesTo determine the association between area and individual measures of social disadvantage and infant health in the UK.DesignSystematic review and meta-analyses.Data sources26 databases and websites, reference lists, experts in the field and hand-searching.Study selection36 prospective and retrospective observational studies with socioeconomic data and health outcomes for infants in the UK, published from 1994 to May 2011.Data extraction and synthesis2 independent reviewers assessed the methodological quality of the studies and abstracted data. Where possible, study outcomes were reported as ORs for the highest versus the lowest deprivation quintile.ResultsIn relation to the highest versus lowest area deprivation quintiles, the odds of adverse birth outcomes were 1.81 (95% CI 1.71 to 1.92) for low birth weight, 1.67 (95% CI 1.42 to 1.96) for premature birth and 1.54 (95% CI 1.39 to 1.72) for stillbirth. For infant mortality rates, the ORs were 1.72 (95% CI 1.37 to 2.15) overall, 1.61 (95% CI 1.08 to 2.39) for neonatal and 2.31 (95% CI 2.03 to 2.64) for post-neonatal mortality. For lowest versus highest social class, the odds were 1.79 (95% CI 1.43 to 2.24) for low birth weight, 1.52 (95% CI 1.44 to 1.61) for overall infant mortality, 1.42 (95% CI 1.33 to1.51) for neonatal and 1.69 (95% CI 1.53 to 1.87) for post-neonatal mortality. There are similar patterns for other infant health outcomes with the possible exception of failure to thrive, where there is no clear association.ConclusionsThis review quantifies the influence of social disadvantage on infant outcomes in the UK. The magnitude of effect is similar across a range of area and individual deprivation measures and birth and mortality outcomes. Further research should explore the factors that are more proximal to mothers and infants, to help throw light on the most appropriate times to provide support and the form(s) that this support should take.
Manganese Superoxide Dismutase Regulates a Metabolic Switch during the Mammalian Cell Cycle
Authors: Sarsour Ehab H. , Kalen Amanda L. , Xiao Zhen , Veenstra Timothy D. , Chaudhuri Leena , Venkataraman Sujatha , Reigan Philip , Buettner Garry R. , Goswami Prabhat C. 
Published: June 2012

Abstract
Proliferating cells consume more glucose to cope with the bioenergetics and biosynthetic demands of rapidly dividing cells as well as to counter a shift in cellular redox environment. This study investigates the hypothesis that manganese superoxide dismutase (MnSOD) regulates cellular redox flux and glucose consumption during the cell cycle. A direct correlation was observed between glucose consumption and percentage of S-phase cells in MnSOD wild-type fibroblasts, which was absent in MnSOD homozygous knockout fibroblasts. Results from electron paramagnetic resonance spectroscopy and flow cytometric assays showed a significant increase in cellular superoxide levels in S-phase cells, which was associated with an increase in glucose and oxygen consumption, and a decrease in MnSOD activity. Mass spectrometry results showed a complex pattern of MnSOD-methylation at both lysine (68, 89, 122, and 202) and arginine (197 and 216) residues. MnSOD protein carrying a K89A mutation had significantly lower activity compared with wild-type MnSOD. Computational-based simulations indicate that lysine and arginine methylation of MnSOD during quiescence would allow greater accessibility to the enzyme active site as well as increase the positive electrostatic potential around and within the active site. Methylation-dependent changes in the MnSOD conformation and subsequent changes in the electrostatic potential around the active site during quiescence versus proliferation could increase the accessibility of superoxide, a negatively charged substrate. These results support the hypothesis that MnSOD regulates a “metabolic switch” during progression from quiescent through the proliferative cycle. We propose MnSOD as a new molecular player contributing to the Warburg effect. Cancer Res; 72(15); 3807–16. ©2012 AACR.
PTEN and NF1 Inactivation in Schwann Cells Produces a Severe Phenotype in the Peripheral Nervous System That Promotes the Development and Malignant Progression of Peripheral Nerve Sheath Tumors
Authors: Keng Vincent W. , Rahrmann Eric P. , Watson Adrienne L. , Tschida Barbara R. , Moertel Christopher L. , Jessen Walter J. , Rizvi Tilat A. , Collins Margaret H. , Ratner Nancy , Largaespada David A. 
Published: June 2012

Abstract
The genetic evolution from a benign neurofibroma to a malignant sarcoma in patients with neurofibromatosis type 1 (NF1) syndrome remains unclear. Schwann cells and/or their precursor cells are believed to be the primary pathogenic cell in neurofibromas because they harbor biallelic neurofibromin 1 (NF1) gene mutations. However, the phosphatase and tensin homolog (Pten) and neurofibromatosis 1 (Nf1) genes recently were found to be comutated in high-grade peripheral nerve sheath tumors (PNST) in mice. In this study, we created transgenic mice that lack both Pten and Nf1 in Schwann cells and Schwann cell precursor cells to validate the role of these two genes in PNST formation in vivo. Haploinsufficiency or complete loss of Pten dramatically accelerated neurofibroma development and led to the development of higher grade PNSTs in the context of Nf1 loss. Pten dosage, together with Nf1 loss, was sufficient for the progression from low-grade to high-grade PNSTs. Genetic analysis of human malignant PNSTs (MPNST) also revealed downregulation of PTEN expression, suggesting that Pten-regulated pathways are major tumor-suppressive barriers to neurofibroma progression. Together, our findings establish a novel mouse model that can rapidly recapitulate the onset of human neurofibroma tumorigenesis and the progression to MPNSTs. Cancer Res; 72(13); 3405–13. ©2012 AACR.
Extensive Promoter DNA Hypermethylation and Hypomethylation Is Associated with Aberrant MicroRNA Expression in Chronic Lymphocytic Leukemia
Authors: Baer Constance , Claus Rainer , Frenzel Lukas P. , Zucknick Manuela , Park Yoon Jung , Gu Lei , Weichenhan Dieter , Fischer Martina , Pallasch Christian Philipp , Herpel Esther , Rehli Michael , Byrd John C. , Wendtner Clemens-Martin , Plass Christoph 
Published: June 2012

Abstract
Dysregulated microRNA (miRNA) expression contributes to the pathogenesis of hematopoietic malignancies, including chronic lymphocytic leukemia (CLL). However, an understanding of the mechanisms that cause aberrant miRNA transcriptional control is lacking. In this study, we comprehensively investigated the role and extent of miRNA epigenetic regulation in CLL. Genome-wide profiling conducted on 24 CLL and 10 healthy B cell samples revealed global DNA methylation patterns upstream of miRNA sequences that distinguished malignant from healthy cells and identified putative miRNA promoters. Integration of DNA methylation and miRNA promoter data led to the identification of 128 recurrent miRNA targets for aberrant promoter DNA methylation. DNA hypomethylation accounted for more than 60% of all aberrant promoter-associated DNA methylation in CLL, and promoter DNA hypomethylation was restricted to well-defined regions. Individual hyper- and hypomethylated promoters allowed discrimination of CLL samples from healthy controls. Promoter DNA methylation patterns were confirmed in an independent patient cohort, with 11 miRNAs consistently showing an inverse correlation between DNA methylation status and expression level. Together, our findings characterize the role of epigenetic changes in the regulation of miRNA transcription and create a repository of disease-specific promoter regions that may provide additional insights into the pathogenesis of CLL. Cancer Res; 72(15); 3775–85. ©2012 AACR.
Molecular Pathways: Targeting Phosphoinositide 3-Kinase p110-Delta in Chronic Lymphocytic Leukemia
Authors: Herman Sarah E.M. , Johnson Amy J. 
Published: June 2012

Abstract
The advent of targeted therapy, specifically to the B-cell receptor (BCR), has changed the convention for the treatment of chronic lymphocytic leukemia (CLL). The phosphoinositide 3-kinase (PI3K) pathway, activated upstream by the BCR, receptor tyrosine kinases, and cytokine receptors, has been a potential target for a multitude of cancers, but until the recent introduction of isoform-specific inhibitors has not been widely used. In this review, we focus on describing the intricate upstream and downstream signaling, leading to cell survival mediated by PI3K in B cells with a specific focus on the impact and importance of the p110δ isoform (which is localized to hematopoietic cells and regulates distinct cellular functions in B cells). In addition, the clinical advances from targeting p110δ are described, with a focus on clinical outcome, toxicities, and rational combination therapies. The experiences with p110δ in CLL have led to a more fundamental understanding of CLL signaling defects and may be predictive of other BCR-directed therapeutics. Clin Cancer Res; 18(15); 4013–8. ©2012 AACR.
Binding of Oxidized Low-Density Lipoprotein on Circulating Platelets Is increased in Patients With Acute Coronary Syndromes and Induces Platelet Adhesion to Vascular Wall In Vivo—Brief Report
Authors: Stellos Konstantinos , Sauter Reinhard , Fahrleitner Manuela , Grimm Juliane , Stakos Dimitrios , Emschermann Frederic , Panagiota Victoria , Gnerlich Stephan , Perk Annegret , Schönberger Tanja , Bigalke Boris , Langer Harald F. , Gawaz Meinrad 
Published: June 2012

Objective—
Hyperlipidemia is associated with platelet hyperactivity. In the present study, we evaluated the binding of oxidized low-density lipoprotein (oxLDL) on the surface of circulating platelets in patients with stable coronary artery disease and acute coronary syndromes and its possible association with platelet activation. Furthermore, the role of oxLDL binding on platelet adhesion to collagen and endothelial cells in vitro as well as after carotid ligation in mice was investigated.

Methods and Results—

Using flow cytometry, patients with acute coronary syndromes (n=174) showed significantly enhanced oxLDL binding compared with patients with stable coronary artery disease (n=182;
P
=0.007). Platelet-bound oxLDL positively correlated with the degree of platelet activation (expression of P-selectin and activated fibrinogen receptor;
P
<0.001 for both). Plasma oxLDL was increased in patients with acute coronary syndromes compared with stable angina pectoris patients. Preincubation of isolated platelets with oxLDL, but not with native LDL, resulted in enhanced platelet adhesion to collagen and activated endothelial cells under high shear stress in vitro, as well as after carotid ligation in C57BL/6J mice and apolipoprotein E
−/−
mice fed a high cholesterol diet.

Conclusion—
Increased platelet-bound oxLDL in patients with acute coronary syndromes may play an important role in atherothrombosis, thus providing a potential future therapeutic target.
A Genome-Wide Association Study Identifies
KNG1
as a Genetic Determinant of Plasma Factor XI Level and Activated Partial Thromboplastin Time
Authors: Sabater-Lleal Maria , Martinez-Perez Angel , Buil Alfonso , Folkersen Lasse , Souto Juan Carlos , Bruzelius Maria , Borrell Montserrat , Odeberg Jacob , Silveira Angela , Eriksson Per , Almasy Laura , Hamsten Anders , Soria José Manuel 
Published: June 2012

Objective—

Elevated plasma levels of coagulation factor XI (FXI) are implicated in the pathogenesis of venous thromboembolism and ischemic stroke, and polymorphisms in the
F11
gene are associated both with risk of venous thromboembolism and an elevated plasma FXI level.

Methods and Results—

Here, we report the first hypothesis-free genome-wide genetic analysis of plasma FXI levels. Two genome-wide significant loci were detected in the family-based Genetic Analysis of Idiopathic Thrombophilia 1 cohort: one located in the
kininogen 1
gene (
KNG1
) (rs710446;
P
=7.98×10
−10
) and one located in the structural
F11
gene (rs4241824;
P
=1.16×10
−8
). Both associations were replicated in a second population-based Swedish cohort. A significant effect on
KNG1
mRNA expression was also seen for the 2 most robustly FXI-associated single nucleotide polymorphisms located in
KNG1
. Furthermore, both
KNG1
single nucleotide polymorphisms were associated with activated partial thromboplastin time, suggesting that FXI may be the main mechanistic pathway by which
KNG1
and
F11
influence activated partial thromboplastin time and risk of thrombosis.

Conclusion—
These findings contribute to the emerging molecular basis of venous thromboembolism and, more importantly, help in understanding the biological regulation of a phenotype that has proved to have promising therapeutic properties in relation to thrombosis.