bluuebunny/crossref_metadata_2025_split huggingface dataset:
Hydrocode modeling of oblique impacts: The fate of the projectile
Authors: PIERAZZO E. , MELOSH H. J. 
Published: February 2010

Abstract— All impacts are oblique to some degree. Only rarely do projectiles strike a planetary surface (near) vertically. The effects of an oblique impact event on the target are well known, producing craters that appear circular even for low impact angles (>15° with respect to the surface). However, we still have much to learn about the fate of the projectile, especially in oblique impact events. This work investigates the effect of angle of impact on the projectile.Sandia National Laboratories' three‐dimensional hydrocode CTH was used for a series of high‐resolution simulations (50 cells per projectile radius) with varying angle of impact. Simulations were carried out for impacts at 90, 60, 45, 30, and 15° from the horizontal, while keeping projectile size (5 km in radius), type (dunite), and impact velocity (20 km/s) constant.The three‐dimensional hydrocode simulations presented here show that in oblique impacts the distribution of shock pressure inside the projectile (and in the target as well) is highly complex, possessing only bilateral symmetry, even for a spherical projectile. Available experimental data suggest that only the vertical component of the impact velocity plays a role in an impact. If this were correct, simple theoretical considerations indicate that shock pressure, temperature, and energy would depend on sin2θ, where θ is the angle of impact (measured from the horizontal). However, our numerical simulations show that the mean shock pressure in the projectile is better fit by a sin θ dependence, whereas shock temperature and energy depend on sin3/2 θ. This demonstrates that in impact events the shock wave is the result of complex processes that cannot be described by simple empirical rules. The mass of shock melt or vapor in the projectile decreases drastically for low impact angles as a result of the weakening of the shock for decreasing impact angles. In particular, for asteroidal impacts the amount of projectile vaporized is always limited to a small fraction of the projectile mass. In cometary impacts, however, most of the projectile is vaporized even at low impact angles.In the oblique impact simulations a large fraction of the projectile material retains a net downrange motion. In agreement with experimental work, the simulations show that for low impact angles (30 and 15°), a downrange focusing of projectile material occurs, and a significant amount of it travels at velocities larger than the escape velocity of Earth.
Crystal‐bearing lunar spherules: Impact melting of the Moon's crust and implications for the origin of meteoritic chondrules
Authors: RUZICKA Alex , SNYDER Gregory A. , TAYLOR Lawrence A. 
Published: February 2010

Abstract— Crystal‐bearing lunar spherules (CLSs) in lunar breccia (14313, 14315, 14318), soil (68001, 24105), and impact‐melt rock (62295) samples can be classified into two types: feldspathic and olivine‐rich. Feldspathic CLSs contain equant, tabular, or acicular plagioclase grains set in glass or a pyroxene‐olivine mesostasis; the less common olivine‐rich CLSs contain euhedral or skeletal olivine set in glass, or possess a barred‐olivine texture. Bulk‐chemical and mineral‐chemical data strongly suggest that feldspathic CLSs formed by impact melting of mixtures of ferroan anorthosite and Mg‐suite rocks that compose the feldspathic crust of the Moon. It is probable that olivine‐rich CLSs also formed by impact melting, but some appear to have been derived from distinctively magnesian lunar materials, atypical of the Moon's crust.Some CLSs contain reversely‐zoned “relic” plagioclase grains that were not entirely melted during CLS formation, thin (≤5 μm thick) rims of troilite or phosphate, and chemical gradients in glassy mesostases attributed to metasomatism in a volatile‐rich (Na‐K‐P‐rich) environment. Crystal‐bearing lunar spherules were rimmed and metasomatized prior to brecciation. Compound CLS objects are also present; these formed by low‐velocity collisions in an environment, probably an ejecta plume, that contained numerous melt droplets.Factors other than composition were responsible for producing the crystallinity of the CLSs. We agree with previous workers that relatively slow cooling rates and long ballistic travel times were critical features that enabled these impact‐melt droplets to partially or completely crystallize in free‐flight. Moreover, incomplete melting of precursor materials formed nucleation sites that aided subsequent crystallization.Clearly, CLSs do not resemble meteoritic chondrules in all ways. The two types of objects had different precursors and did not experience identical rimming processes, and vapor fractionation appears to have played a less important role in establishing the compositions of CLSs than of chondrules. However, the many detailed similarities between CLSs and chondrules indicate that it is more difficult to rule out an origin for some chondrules by impact melting than some have previously argued. Differences between CLSs, chondrules, and their host rocks possibly can be reconciled with an impact‐melt origin for some chondrules when different precursors, the higher gravity of the Moon compared to chondrite parent bodies, and the likely presence of nebular gas during chondrule formation are taken into account.
The metallographic cooling rate method revised: Application to iron meteorites and mesosiderites
Authors: HOPFE W. D. , GOLDSTEIN J. I. 
Published: February 2010

Abstract— A major revision of the current Saikumar and Goldstein (1988) cooling rate computer model for kamacite growth is presented. This revision incorporates a better fit to the α/α + γ phase boundary and to the γ/α + γ phase boundary particularly below the monotectoid temperature of 400 °C. A reevaluation of the latest diffusivities for the Fe‐Ni system as a function of Ni and P content and temperature is made, particularly for kamacite diffusivity below the paramagnetic to ferromagnetic transition.The revised simulation model is applied to several iron meteorites and several mesosiderites. For the mesosiderites we obtain a cooling rate of 0.2 °C/Ma, about 10x higher than the most recent measured cooling rates. The cooling rate curves from the current model do not accurately predict the central nickel content of taenite halfwidths smaller than ∼10 μm. This result calls into question the use of conventional kamacite growth models to explain the microstructure of the mesosiderites. Kamacite regions in mesosiderites may have formed by the same process as decomposed duplex plessite in iron meteorites.
Exposure history of the St‐Robert (H5) fall
Authors: Leya I. , Wieler R. , Aggrey K. , Herzog G. F. , Schnabel C. , Metzler K. , Hildebrand A. R. , Bouchard M. , Jull A. J. T. , Andrews H. R. , Wang M‐S. , Ferko T. E. , Lipschutz M. E. , Wacker J. F. , Neumann S. , Michel R. 
Published: February 2010

Abstract—The compositionally typical H5 chondrite St‐Robert has an exposure age, 7.8 Ma, indistinguishable from that of the main cluster of H chondrites. Small values of the cosmogenic22Ne/21Ne ratio in interior samples imply a pre‐atmospheric radius on the order of 40 cm. Sample depths based on tracks and the production rates of Bhattacharyaet al.(1973) range from 6 to ∼40 cm and are generally larger than depths estimated from published60Co activities, perhaps because the track production rates adopted are too high. Depth profiles of the production rates of14C,36Cl,26Al,10Be, and21Ne in stony material show increases with depth and reach levels 5% to 15% higher than expected from modeling calculations. The maximum concentrations in St‐Robert are, however, generally comparable to those measured for the L5 chondrite, Knyahinya, whose pre‐atmospheric radius of ∼45 cm is thought to lead to the maximum possible production rates in chondrites. We infer that the pre‐atmospheric radius of St‐Robert was within 5 cm of the value that supports maximum production rates (i.e., 45 ± 5 cm). This radius corresponds to a pre‐atmospheric mass of (1.3 ± 0.4) × 103kg.The agreement of exposure ages for St‐Robert obtained in several different ways and the similarity of the depth profiles for14C,26Al,10Be, and21Ne argue against a lengthy pre‐exposure of St‐Robert on the parent body and against a two‐stage exposure after launch from the parent body. Following Morbidelli and Gladman (1998), we suggest that St‐Robert was chipped from deep in its parent body, spent the next 7–8 Ma without undergoing a major collision, was nudged gradually into an orbital resonance with Jupiter, and then traveled quickly to Earth.
Molecular and chiral analyses of some protein amino acid derivatives in the Murchison and Murray meteorites
Authors: PIZZARELLO Sandra , COOPER George W. 
Published: February 2010

Abstract— The varied organic suite extracted from the Murchison meteorite contains several amino acids that are common to the biosphere. Some of these have been found to be non‐racemic, but the indigenous nature of their L‐enantiomeric excesses has been subject to debate in view of possible terrestrial contamination. We have investigated two amino acids of common terrestrial and meteoritic occurrence, alanine and glutamic acid, and assessed their indigenous enantiomeric ratios in the Murchison and Murray meteorites through the ratios of some of their derivatives. Analyzed were N‐acetyl alanine, α‐imino propioacetic acid, N‐acetyl glutamic acid and pyroglutamic acid.Both alanine derivatives were found to be racemic, while those of glutamic acid showed L‐enantiomeric excesses varying from 16% to 47.2% for pyroglutamic acid, and from 8.6% to 41% for N‐acetyl glutamic acid. The δ13C was determined for the two enantiomers of Murchison pyroglutamic acid both before and after acid hydrolysis to glutamic acid. The values of +27.7%0 (D‐pyro), +10.0%0 (L‐pyro), +32.2%0 (D‐glu) and +14.6%0 (L‐glu) were obtained.The racemic nature of alanine derivatives strongly suggests that alanine itself, as indigenous to the meteorite, is racemic. The explanation of the L‐enantiomeric excesses found for glutamic acid derivatives is less direct; however, the variability of the enantiomeric ratios for these compounds and the distinctly lower δ13C values determined for pyroglutamic L‐enantiomer point to a terrestrial contamination, possibly dating to the time of fall.
Refractory calcium‐aluminum‐rich inclusions and aluminum‐diopside‐rich chondrules in the metal‐rich chondrites Hammadah al Hamra 237 and Queen Alexandra Range 94411
Authors: KROT Alexander N. , McKEEGAN Kevin D. , RUSSELL Sara S. , MEIBOM Anders , WEISBERG Michael K. , ZIPFEL Jutta , KROT Tatiana V. , FAGAN Timothy J. , KEIL Klaus 
Published: February 2010

Abstract— The metal‐rich chondrites Hammadah al Hamra (HH) 237 and Queen Alexandra Range (QUE) 94411, paired with QUE 94627, contain relatively rare (<1 vol%) calcium‐aluminum‐rich inclusions (CAIs) and Al‐diopside‐rich chondrules. Forty CAIs and CAI fragments and seven Al‐diopside‐rich chondrules were identified in HH 237 and QUE 94411/94627. The CAIs, ∼50–400 μm in apparent diameter, include (a) 22 (56%) pyroxene‐spinel ± melilite (+forsterite rim), (b) 11 (28%) forsterite‐bearing, pyroxene‐spinel ± melilite ± anorthite (+forsterite rim) (c) 2 (5%) grossite‐rich (+spinel‐melilite‐pyroxene rim), (d) 2 (5%) hibonite‐melilite (+spinel‐pyroxene ± forsterite rim), (e) 1 (2%) hibonite‐bearing, spinel‐perovskite (+melilite‐pyroxene rim), (f) 1 (2%) spinel‐melilite‐pyroxene‐anorthite, and (g) 1 (2%) amoeboid olivine aggregate. Each type of CAI is known to exist in other chondrite groups, but the high abundance of pyroxene‐spinel ± melilite CAIs with igneous textures and surrounded by a forsterite rim are unique features of HH 237 and QUE 94411/94627. Additionally, oxygen isotopes consistently show relatively heavy compositions with Δ17O ranging from −6%0 to −10%0 (1σ = 1.3%0) for all analyzed CAI minerals (grossite, hibonite, melilite, pyroxene, spinel). This suggests that the CAIs formed in a reservoir isotopically distinct from the reservoir(s) where “normal”, 16O‐rich (Δ17O < −20%0) CAIs in most other chondritic meteorites formed.The Al‐diopside‐rich chondrules, which have previously been observed in CH chondrites and the unique carbonaceous chondrite Adelaide, contain Al‐diopside grains enclosing oriented inclusions of forsterite, and interstitial anorthitic mesostasis and Al‐rich, Ca‐poor pyroxene, occasionally enclosing spinel and forsterite. These chondrules are mineralogically similar to the Al‐rich barred‐olivine chondrules in HH 237 and QUE 94411/94627, but have lower Cr concentrations than the latter, indicating that they may have formed during the same chondrule‐forming event, but at slightly different ambient nebular temperatures. Aluminum‐diopside grains from two Al‐diopside‐rich chondrules have O‐isotopic compositions (Δ17O ≅ −7 ± 1.1 %0) similar to CAI minerals, suggesting that they formed from an isotopically similar reservoir. The oxygen‐isotopic composition of one Ca, Al‐poor cryptocrystalline chondrule in QUE 94411/94627 was analyzed and found to have Δ17O ≅ −3 ± 1.4%0.The characteristics of the CAIs in HH 237 and QUE 94411/94627 are inconsistent with an impact origin of these metal‐rich meteorites. Instead they suggest that the components in CB chondrites are pristine products of large‐scale, high‐temperature processes in the solar nebula and should be considered bona fide chondrites.
Pattern of Serum Cytokine Expression and T-Cell Subsets in Sickle Cell Disease Patients in Vaso-Occlusive Crisis
Authors: Musa Bolanle O. P. , Onyemelukwe Geoffrey C. , Hambolu Joseph O. , Mamman Aisha I. , Isa Albarka H. 
Published: February 2010

ABSTRACTThe pathogenesis of sickle vaso-occlusive crisis (VOC) in sickle cell disease (SCD) patients involves the accumulation of rigid sickle cells and the stimulation of an ongoing inflammatory response, as well as the stress of infections. The immune response, via cytokine imbalances and deregulated T-cell subsets, also has been proposed to contribute to the development of VOC. In this study, a panel of high-sensitivity cytokine kits was used to investigate cytokines in the sera of SCD patients in VOC. The results were compared primarily with those for stable SCD patients and secondarily with those for normal healthy people who served as controls. The cytokines studied included interleukin-2 (IL-2), IL-4, and IL-10. Lymphocyte subsets of patients with VOC were also studied and were compared with those of both control groups (20 stable patients without crisis [SCD group] and 20 normal healthy controls [NHC]). The VOC group was notable for remarkably elevated levels of IL-4, among the three cytokines tested, compared with those for the SCD and NHC groups. Patients with VOC also differed from stable SCD patients and NHC by having notably lower IL-10 levels, as well as the lowest ratio of CD4+to CD8+T cells (0.7). The patterns of the proinflammatory cytokine IL-2 did not differ between VOC and stable SCD patients, but NHC had significantly lower IL-2 levels than both the VOC and SCD groups. Our results demonstrate coexisting levels, both high and low, of TH1- and TH2-type cytokines, as well as diminished levels of T-cell subsets in VOC. These results are discussed in an effort to better understand the importance of the immune system profile in the pathogenesis of sickle cell VOC. Since the possibility that a cytokine imbalance is implicated in the pathogenesis of sickle cell crisis has been raised, our results should prompt further investigation of the host immune response in terms of TH1 and TH2 balance in sickle cell crisis.
Progesterone and 17β-Estradiol Enhance Regulatory Responses to Human Papillomavirus Type 16 Virus-Like Particles in Peripheral Blood Mononuclear Cells from Healthy Women
Authors: Marks Morgan A. , Gravitt Patti E. , Burk Robert D. , Studentsov Yevgeniy , Farzadegan Homayoon , Klein Sabra L. 
Published: February 2010

ABSTRACTHuman papillomavirus (HPV) virus-like particle (VLP) vaccines are highly effective at preventing viral infections and the development of precancerous lesions through the induction of high-titer neutralizing antibodies and strong cell-mediated immune responses. Women taking combined oral contraceptives (COCs), however, show large variabilities in the magnitudes of their antibody responses. The goal of the present study was to determine the effects of 17β-estradiol (E2) and progesterone (P4) alone and in combination on the cellular immune response to HPV type 16 (HPV-16) VLPsin vitro. Peripheral blood mononuclear cells (PBMCs) from healthy donor women were stimulatedin vitrowith HPV-16 VLPs (2.5 μg/ml) in the presence of E2 and P4 administered either alone or in combination; and lymphoproliferation, cytokine production, transcription factor expression, and steroid hormone receptor expression were analyzed. HPV-16 VLPs significantly increased the levels of lymphoproliferation, proinflammatory cytokine (gamma interferon [IFN-γ], interleukin-1β [IL-1β], IL-2, IL-6, IL-8, IL-12p70, IL-17, tumor necrosis factor alpha [TNF-α]) production, anti-inflammatory cytokine (IL-1ra, IL-10) production, and the expression of Erα and Erβ but decreased the levels ofFoxp3expression and production of transforming growth factor β (TGF-β). Exposure of PBMCs to E2 and P4 either alone or in combination significantly decreased the levels of lymphoproliferation and production of proinflammatory cytokines (IFN-γ, IL-12p70, TNF-α) but increased the levels of production of IL-10 and TGF-β and the expression ofFoxp3in response to HPV-16 VLPs. Treatment of cells with biologically relevant concentrations of sex steroid hormones suppressed the inflammatory response and enhanced the regulatory response to HPV-16 VLPs, which may have implications for predicting the long-term efficacy of HPV vaccines, adverse events, and cross-protection among women taking COCs.
Rapid and Direct Quantification of Viable
Candida
Species in Whole Blood by Use of Immunomagnetic Separation and Solid-Phase Cytometry
Authors: Vanhee Lies M. E. , Meersseman Wouter , Lagrou Katrien , Maertens Johan , Nelis Hans J. , Coenye Tom 
Published: February 2010

ABSTRACT

Candida
species are a common source of nosocomial bloodstream infections in critically ill patients. The sensitivity of the traditional diagnostic procedure based on blood culture is variable, and it usually takes 2 to 4 days before growth of
Candida
species is detected. We developed a 4-h method for the quantification of
Candida
species in blood, combining immunomagnetic separation (IMS) with solid-phase cytometry (SPC) using viability labeling. Additionally,
Candida albicans
cells could be identified in real time by using fluorescent
in situ
hybridization. By analysis of spiked blood samples, our method was shown to be sensitive and specific, with a low detection limit (1 cell/ml of blood). In a proof-of-concept study, we applied the IMS/SPC method to 16 clinical samples and compared it to traditional blood culture. Our method proved more sensitive than culture (seven samples were positive with IMS/SPC but negative with blood culture), and identification results were in agreement. The IMS/SPC data also suggest that mixed infections might occur frequently, as
C. albicans
and at least one other
Candida
species were found in five samples. Additionally, in two cases, high numbers of cells (175 to 480 cells/ml of blood) were associated with an endovascular source of infection.
Full-Genome Sequence Analysis of a Multirecombinant Echovirus 3 Strain Isolated from Sewage in Greece
Authors: Kyriakopoulou Zaharoula , Dedepsidis Evaggelos , Pliaka Vaia , Tsakogiannis Dimitris , Pratti Anastassia , Levidiotou-Stefanou Stamatina , Markoulatos Panayotis 
Published: February 2010

ABSTRACT
An echovirus 3 (Echo3) strain (strain LR31G7) was isolated from a sewage treatment plant in Greece in 2005. Full-genome molecular, phylogenetic, and SimPlot analyses were conducted in order to reveal the evolutionary pathways of the isolate. Nucleotide and phylogenetic analyses of part of the VP1 genomic region revealed that the isolated strain correlates with Echo3 strains isolated during the same year in France and Japan, implying that the same virus circulated in Europe and Asia. LR31G7 was found to be a recombinant that shares the 3′ part of its genome with an Echo25 strain isolated from asymptomatic infants in Norway in 2003. Nucleotide and SimPlot analyses of the VP1-2A junction, where the recombination was located, revealed the exact recombination breakpoint (nucleotides 3357 to 3364). Moreover, there is evidence that recombination events had occurred in 3B-3D region in the evolutionary history of the isolate. Our study indicates that recombination events play major roles in enterovirus evolution and that the circulation of multirecombinant strains with unknown properties could be potentially dangerous for public health.
Scrub Typhus in Previously Unrecognized Areas of Endemicity in China
Authors: Zhang Shouyin , Song Hongbin , Liu Yan , Li Qun , Wang Yong , Wu Jiabin , Wan Junfeng , Li Guolan , Yu Changjun , Li Xiuyong , Yin Wenwu , Xu Zhen , Liu Bo , Zhang Qian , Wan Kanglin , Li Guichang , Fu Xiuping , Zhang Jingshan , He Jinrong , Hai Rong , Yu Dongzheng , Walker David H. , Xu Jianguo , Yu Xue-Jie 
Published: February 2010

ABSTRACT

Scrub typhus, caused by
Orientia tsutsugamushi
, has emerged recently in areas of northern China where the disease had not been known to exist. We analyzed epidemiological, clinical, and laboratory data for 104 patients who were admitted to a hospital in Fuyang City between 26 September and 1 November 2008. We showed that the major clinical manifestations of the patients were fever (100%), headache (82%), myalgias (77%), eschar (67%), rash (52%), and unusual facial flushing (62%). Among the 104 patients, the sera of 98% contained IgM antibodies to
O. tsutsugamushi
detected by indirect immunofluorescence assays (IFA), and DNA of the
O. tsutsugamushi
56-kDa gene was amplified by PCR from the blood of 36 patients. We conclude that 104 patients were infected with scrub typhus in Fuyang City, Anhui Province. Our study indicates that physicians need to consider the diagnosis of scrub typhus for febrile patients living in northern China, where scrub typhus had not been considered to exist in the past.
Prompt and Successful Toxin-Targeting Treatment of Three Patients with Necrotizing Pneumonia Due to
Staphylococcus aureus
Strains Carrying the Panton-Valentine Leukocidin Genes
Authors: Rouzic Nicolas , Janvier Frédéric , Libert Nicolas , Javouhey Etienne , Lina Gerard , Nizou Jacques-Yves , Pasquier Pierre , Stamm Didier , Brinquin Louis , Pelletier Christophe , Vandenesch François , Floret Daniel , Etienne Jerome , Gillet Yves 
Published: February 2010

ABSTRACT

Three patients with extensive necrotizing pneumonia due to Panton-Valentine leukocidin-positive
Staphylococcus aureus
strains and with aggravating factors (leukopenia count of less than 3 × 10
9
/liter in all three cases and hemoptysis in two cases) were successfully treated with toxin-suppressing agents introduced rapidly after hospital admission.