bluuebunny/crossref_metadata_2025 huggingface dataset:
Expression and Functional Significance of Adhesion Molecules on Cultured Endothelial Cells in Response to Ionizing Radiation
Authors: PRABHAKARPANDIAN BALABHASKAR , GOETZ DOUGLAS J. , SWERLICK ROBERT A. , CHEN XIN , KIANI MOHAMMAD F.
Published: January 2010

Objective: Upregulation of adhesion molecules on endothelial cells following irradiation has been shown, but the functional significance of this upregulation in various endothelial cell lines is not clear. We have developed an in vitro flow model to study the functional consequences of the radiation‐induced upregulation of E‐selectin and intercellular adhesion molecule (ICAM‐1).

Methods: Human dermal microvascular endothelial cells (HDMEC), human umbilical vein endothelial cells (HUVEC), or transformed human microvascular endothelial cells (HMEC‐1) were grown in 35‐mm dishes and irradiated with a single dose of 10 Gy. HL‐60 (human promyelocytic leukemia) cells were perfused over the irradiated endothelial cells in a parallel plate flow chamber at shear stress ranging from 0.5 to 2.0 dynes/cm2. Flow cytometry was used to quantify the expression of E‐selectin and ICAM‐1 on the various endothelial cells.

Results: Flow cytomeric analysis revealed an upregulation of ICAM‐1 expression on all three cell types postirradiation (post‐IR), and an upregulation of E‐selectin expression only on HDMEC post‐IR. E‐selectin expression was detected on control HDMEC, but at a lower level than that detected on post‐IR HDMEC. Flow assays revealed a significant increase in the number of rolling and firmly adherent HL‐60 cells on post‐IR HDMEC at shear stress ≤1.5 dynes/cm2; pretreatment of control and irradiated HDMEC with antibodies to E‐selectin and ICAM‐1 significantly diminished the number of rolling and firmly adherent HL‐60 cells, respectively. No rolling or firm adhesion of HL‐60 cells was observed on HUVEC or HMEC‐1 monolayers post‐IR.

Conclusion: These findings suggest that ICAM‐1 is upregulated on irradiated HDMEC, HUVEC, and HMEC‐1. E‐selectin is upregulated to a functional level only on irradiated HDMEC, and not on irradiated HUVEC or HMEC‐1.
What's New in the Cerebral Microcirculation?
Authors: HEISTAD DONALD D.
Published: January 2010

The first part of this paper focuses on unusual aspects of the cerebral circulation. Cerebral vessels have less smooth muscle and adventitia than other vessels, and the endothelial blood‐brain barrier is unique. Because the wall of the arteries is thin, one might expect that the vessels are especially vulnerable to rupture. Pressure in intracranial arteries, however, is lower than in other arteries, because resistance of larger cerebral arteries is remarkably high. The low pressure in cerebral arteries presumably protects against rupture of the vessels. The second part of the paper summarizes some new insights into regulation of cerebral circulation. One concept is that “breakthrough” of autoregulation, with dilatation of cerebral vessels at high levels of pressure, is an active process, rather than a passive phenomenon. This conclusion is based on the finding that inhibitors of calcium‐dependent potassium channels greatly attenuate the cerebral vasodilator response during acute hypertension. The third part of the paper focuses on effects of gene transfer to cerebral blood vessels. Gene transfer to intracranial and extracranial vessels is feasible and vasomotor function can be altered. Gene transfer has proven to be useful to study vascular biology, and we are optimistic that the approach will ultimately lead to gene therapy.
Reciprocal Regulation of Endothelial Substrate Adhesion and Barrier Function
Authors: ALEXANDER J. STEVEN , ZHU YANAN , ELROD JOHN W. , ALEXANDER BRETT , COE LAURA , KALOGERIS T.J. , FUSELER JOHN
Published: January 2010

Objective: To examine how cell‐substrate adhesion is regulated during barrier changes produced by exposure to inflammatory mediators.

Methods: Lung microvascular endothelial monolayers were treated with test agents ± blockers, and barrier was measured by transendothelial resistance; cell‐substrate adhesion was assessed by surface area conservation after trypsin treatment of monolayers. Protein phosphorylation and distribution were assayed by immunoblotting and fluorescent microscopy, respectively.

Results: H2O2, histamine, bradykinin, and thrombin, decreased endothelial barrier function, and enhanced adhesion to the substratum. H2O2 enhanced cell adhesion to the substrate in a concentration (0–1 mM)‐ and time (0–60 minutes)‐ dependent fashion. This effect of H2O2 reversed within 120 minutes of removal of H2O2 and was blocked by the mean arterial pressure (MAP) kinase inhibitor, PD98059 and by chelating cytoplasmic Ca2+ but not PKC or PKG inhibition. H2O2 also stimulated tyrosine phosphorylation of several proteins and increased the association of the focal adhesive proteins paxillin, talin, and vinculin with the cytoskeleton and may promote localization of these proteins to junctions.

Conclusions: Our data indicate that inflammatory mediators reduce cell‐cell contact, contributing to reduced solute barrier and simultaneously enhanced substrate binding, which may be reciprocal events in barrier regulation in vitro and in vivo.
C1‐Esterase‐Inhibitor Treatment at Early Reperfusion of Hemorrhagic Shock Reduces Mesentery Leukocyte Adhesion and Rolling
Authors: HORSTICK GEORG , KEMPF TIBOR , LAUTERBACH MICHAEL , BHAKDI SUCHARIT , KOPACZ LAZLO , HEIMANN AXEL , MALZAHN MICHAEL , HORSTICK MARINA , MEYER JÜRGEN , KEMPSKI OLIVER
Published: January 2010

Objective: Complement activation probably plays a pathogenic role in multiple organ failure in shock. This study evaluates the effects of C1‐esterase‐inhibitor treatment on leukocyte‐endothelial interaction in the mesenteric microcirculation in hemorrhagic shock.

Methods: Rats underwent median laparotomy and exteriorization of an ileal loop for intravital microscopy of the mesenteric microcirculation. Volume controlled hemorrhagic shock was provoked by arterial blood withdrawal (2.5 mL/100 g body wt. for 60 minutes) followed by a 4‐hour reperfusion period. C1‐INH (100 IU/kg body wt. i.v.) or 0.9% NaCl i.v. were administered as a bolus at the beginning of reperfusion. Reperfusion time mimicked a “pre‐hospital” phase of 30 minutes followed by a quasi “in‐hospital” phase of 3.5 hours. The “in‐hospital” phase was initiated by substitution of blood followed by fluid resuscitation with normal saline.

Results: Application of C1‐INH markedly reduced rolling and adherent leukocytes to numbers approaching baseline values. Vmax and shear rate of the mesenteric microcirculation improved in both groups after reperfusion with a trend to higher values in the C1‐INH group (n.s.p= 0.08).

Conclusion: C1‐INH applied in a bolus dose of 100 IU/kg body wt. i.v. abrogated enhanced leukocyte adhesion and rolling in the mesenteric microcirculation after hemorrhagic shock. Single bolus treatment with a complement inhibitor may provide clinical benefit when applied at an early stage of reperfusion during hemorrhagic shock.
Differential Effect of Cytochrome P‐450 ω‐Hydroxylase Inhibition on O2‐Induced Constriction of Arterioles in SHR With Early and Established Hypertension
Authors: KUNERT MARY PAT , ROMAN RICHARD J. , FALCK JOHN R. , LOMBARD JULIAN H.
Published: January 2010

Objective: To determine whether two structurally and mechanistically different inhibitors of cytochrome P‐450 ω‐hydroxylase would alter the enhanced vasoconstrictor response to elevated PO2in arterioles of spontaneously hypertensive rats (SHR). Cytochrome P‐450 ω‐hydroxylases, which catalyze the formation of the vasoconstrictor 20‐hydroxyeicosatetraenoic acid from arachidonic acid, have been proposed to serve as microvascular O2sensors.

Methods: Arteriolar diameters were measured in thein situcremaster muscle of 4‐ to 6‐ and 12‐ to 16‐week‐old SHR and normotensive Wistar‐Kyoto (WKY) controls during superfusion with physiological salt solution (PSS) equilibrated with 0% O2and 21% O2before and after P‐450 enzyme inhibition.

Results: The P‐450 ω‐hydroxylase inhibitors 17‐octadecynoic acid (17‐ODYA) and N‐methylsulfonyl‐12, 12‐dibromododec‐11‐enamide (DDMS) significantly reduced O2‐induced constriction of arterioles of 12‐ to 16‐week‐old SHR and WKY and eliminated the difference in the response between the two groups. In contrast, both enzyme inhibitors attenuated the O2‐induced constriction of arterioles in the younger WKY, but not in the 4‐ to 6‐week‐old SHR.

Conclusions: These results support the hypothesis that cytochrome P‐450 4A may act as an O2sensor in the skeletal muscle microcirculation and suggest that 20‐hydroxyeicosatetraenoic acid plays an important role in the enhanced response to elevated PO2in the SHR with established hypertension. Other mechanisms seem to contribute to the enhanced sensitivity of arterioles to elevated PO2in young SHR during the early development of hypertension.
A comparative approach to understanding factors limiting abundance patterns and distributions in a fig tree–fig wasp mutualism
Authors: Warren Marié , Robertson Mark P. , Greeff Jaco M.
Published: January 2010

Numerous factors affect distribution and abundance. Due to their intimate host association, pollinating fig wasps are expected to occupy the entire distribution of their host fig. An understanding of the physiology of fig wasp species and the factors affecting adult survival are important for understanding and explaining wasp abundance and distribution patterns. We examine distribution and abundance patterns of a fig tree–fig wasp system in which the non‐pollinator (Ceratosolen galili) has been reported to be rarer than the pollinator (Ceratosolenarabicus) in drier areas due to lower desiccation tolerance. Both species are closely related and utilise the same oviposition sites onFicus sycomorus.We used ecological niche modelling to determine whetherC. galilicovers the range ofF. sycomorusand whether it is consistently rarer thanC. arabicus.We examined emergence times, critical thermal limits, desiccation and starvation tolerances of the wasps. The suggested rarity ofC. galilirelates to lower abundance in certain months and at certain localities but a similar number of occurrence records within the distributional range (except in arid regions, e.g. Namibia). In contrast toC. galili,C. arabicushas a wider thermal range, lives longer under hydrating and dehydrating conditions and is a nocturnal flier. The synergistic effect of physiological tolerances and flight time differences exacerbate the less favourable conditions available toC. galiliduring flight and location of receptive figs. These factors enableC. arabicusto survive for longer thanC. galili, meaning that they are more likely to disperse to trees that are flowering further away in space and time. Combining correlative and mechanistic approaches has aided us in understanding the ecological niches of these species.
Induction concurrent chemoradiotherapy compared with induction radiotherapy for superior sulcus non‐small cell lung cancer: a retrospective study
Authors: LI Jian , DAI Chun‐Hua , SHI Shun‐Bing , BAO Qian‐Lei , YU Li‐Chao , WU Jian‐Rong
Published: January 2010

Aim: To evaluate the efficacy of current chemoradiotherapy on improvement of survival in patients with superior sulcus non‐small cell lung cancer (NSCLC).

Methods: We retrospectively reviewed the data of 39 patients with superior sulcus NSCLC treated with induction therapy followed surgery. The patients were divided into two groups according to the induction approach: the induction radiotherapy (RT) group (1993–1999), and the induction chemoradiotherapy (CT/RT) group (since 1999).

Results: The rate of complete resection was 65 percent in the RT group (n = 17) compared with 91 percent in the CT/RT group (n = 22,P = 0.024). Complete pathological responses from induction therapy were 12 percent in the RT group and 45 percent in the CT/RT group (P = 0.032). Overall survival (OS) was significantly longer in patients who received CT/RT than that in those who received RT, with 2‐ and 5‐year survival rates of 77.3 percent and 36.4 percent versus 41.2 percent and 11.8 percent, respectively (P = 0.007). CT/RT also associated with a markedly longer tumor‐free survival (TFS), with a median TFS of 40 and 17 months, respectively (P = 0.007). Patients achieved complete resection or complete pathological response had a significantly better survival than those with incomplete resection or pathological partial responses and no change (P < 0.0005 andP = 0.001, respectively).

Conclusion: Our results indicate that CT/RT followed by surgery can significantly improve OS and TFS, and may be considered as an optimal option in treatment of patients with superior sulcus NSCLC.
Promoting Positive Developmental Outcomes in Sexual Minority Youth Through Best Practices in Clinic–School Consultation
Authors: Hirsch Amanda J. , Carlson John S. , Crowl Alicia L.
Published: January 2010

TOPIC:  Educational and healthcare service delivery systems play an important role within the lives of sexual minority youth.

PURPOSE:  To provide justification and recommendations for improving the coordination and collaboration of school‐based mental health professionals and child and adolescent psychiatric nurses via presentation of a set of consultation best practices.

SOURCES:  Multidisciplinary literature specific to sexual minority youth, school climate, clinical experience, and consultation practices.

CONCLUSION:  Nurses are in a position to advocate for and provide education about sexual minority youth in schools and to provide direct support to this population. By creating collaborative relationships across clinics and schools, information and expertise can be shared and applied to affect change and lead to positive outcomes for all students.
Simulated versus observed UV emission at high redshift: a hint for a clumpy interstellar medium?
Authors: Forero-Romero Jaime E. , Yepes Gustavo , Gottlöber Stefan , Knollmann Steffen R. , Khalatyan Arman , Cuesta Antonio J. , Prada Francisco
Published: January 2010

We discuss the rest-frame UV emission between 5 < z < 7 from the MareNostrum High-z Universe, an smoothed particle hydrodynamics simulation done with more than 2 billion particles. Cosmological simulations of galaxy formation generally overpredict the UV rest-frame luminosity function at high redshift, both at the bright and faint ends. In this Letter, we explore a dust attenuation model where a larger extinction is applied to star populations younger than a given age, mimicking the effect of a clumpy interstellar medium. We show that this scenario fits reasonably well both the UV luminosity functions and the UV continuum slopes derived from observations. The model assumes a large obscuration for stars younger than 25 Myr from the gas clouds where they should be embedded at their formation time. We find that the optical depth in these clouds should be between 30 and 100 times larger than the mean optical depth for the homogeneous part of the interstellar medium. These values are one order of magnitude larger than those estimated in local galaxies. Therefore, we conclude that Λ cold dark matter predictions for the high-z UV emission can accommodate the current observations if we consider a dust extinction model based on the assumption of a clumpy environment at high redshift.
NGC 300 X-1 is a Wolf-Rayet/black hole binary
Authors: Crowther P. A. , Barnard R. , Carpano S. , Clark J. S. , Dhillon V. S. , Pollock A. M. T.
Published: January 2010

We present Very Large Telescope/FORS2 time-series spectroscopy of the Wolf–Rayet (WR) star #41 in the Sculptor group galaxy NGC 300. We confirm a physical association with NGC 300 X-1, since radial velocity variations of the He iiλ4686 line indicate an orbital period of 32.3 ± 0.2 h which agrees at the 2σ level with the X-ray period from Carpano et al. We measure a radial velocity semi-amplitude of 267 ± 8 km s−1, from which a mass function of 2.6 ± 0.3 M⊙ is obtained. A revised spectroscopic mass for the WN-type companion of 26+7−5 M⊙ yields a black hole mass of 20 ± 4 M⊙ for a preferred inclination of 60°–75°. If the WR star provides half of the measured visual continuum flux, a reduced WR (black hole) mass of 15+4−2.5 M⊙ (14.5+3−2.5 M⊙) would be inferred. As such, #41/NGC 300 X-1 represents only the second extragalactic WR plus black hole binary system, after IC 10 X-1. In addition, the compact object responsible for NGC 300 X-1 is the second highest stellar-mass black hole known to date, exceeded only by IC 10 X-1.
First report on C‐banding and fluorescent banding in species of Dieuches (Rhyparochrominae: Lygaeidae: Heteroptera)
Authors: KAUR Harbhajan , SUMAN Vikas , KAUR Rajdeep
Published: January 2010

Although the karyotypes of twelve species of Dieuches Dohrn, 1860 belonging to Rhyparochrominae have been described so far, there is no information about heterochromatin and its characterization in terms of base composition for any of the species. In the present paper, C‐banding and fluorescent banding have been applied for the first time to three species of Dieuches: D. uniguttatus, D. insignis (2n = 12 = 8A + 2m + XY) and D. coloratus (2n = 14 = 10A + 2m + XY). Dieuches uniguttatus and D. insignis show distinct terminal C‐bands along with a few interstitial bands in all the autosomal bivalents, whereas in D. coloratus, one autosomal pair is almost completely heterochromatic, three show C‐positive bands while one is totally euchromatic. The sex chromosomes too show heterogeneity in distribution of C‐heterochromatin among three Dieuches species. Characterization of heterochromatin in D. uniguttatus and D. insignis using DAPI/CMA3 staining reveals that in D. uniguttatus, C‐ heterochromatin blocks of all the autosomal bivalents, which are predominantly A–T rich, whereas in D. insignis, these are rich both in A–T and G–C. In D. uniguttatus, sex chromosomes X and Y have localized G–C rich regions whereas in D. insignis, these are scattered in X and absent in Y. As variations in the heterochromatin represent the main source of karyological differentiation among and within species, it seems that there occurred extensive redistribution of heterochromatin within the complement as the three species evolved. There is need for cytological details of more species to understand evolutionary aspects in the genus Dieuches.
Behavioral response of female Helicoverpa armigera (Hübner) to different plant part extracts of African marigold Tagetes erecta (L.)
Authors: SENI Atanu , DILAWARI Vinod K. , GUPTA Virash K.
Published: January 2010

The flowering stage of African marigold Tagetes erecta (L.) was the most preferred for oviposition by Helicoverpa armigera (Hübner). The lower sides of leaf margins received more eggs compared to buds, stem tip and flowers. Olfactometer studies revealed that more female moths were attracted towards the flower extracts, followed by leaf, bud and stem tip extracts of African marigold. The thin layer chromatography analysis of these extracts showed a blend of compounds including careen, ocimene, methyl benzoate, phenyl acetaldehyde and phenyl ethanol. Attempts have been made to correlate insect behavior with the presence of these compounds.
Review of family Lucanidae (Insecta: Coleoptera) in Korea with the description of one new species
Authors: KIM Sang Il , KIM Jin Ill
Published: January 2010

This paper provides a review of the family Lucanidae in Korea, which consists of 17 species belonging to 9 genera. One new species,Dorcus tenuihirsutussp. nov., is described and the following taxonomical changes are proposed:Aegus laevicollisSaunders, 1854 is newly identified asAegus laevicollissubnitidus Waterhouse, 1873;Macrodorcas striatipennisMotschulsky, 1861 is removed from the Korean fauna because this record is thought to have been based on the misinterpretation of locality and misidentification;Neolucanus saundersiiParry, 1864 is removed from the Korean fauna because this record is thought to have been based on misidentification.
Is More Truly Merrier?: Mentoring and the Practice of Law
Authors: KAY FIONA M. , WALLACE JEAN E.
Published: January 2010

Cet article examine deux questions sur le mentorat. D'abord, qui est le plus susceptible de bénéficier de services de mentorat au cours de sa carrière? Ensuite, comment le mentorat influence‐t‐il les carrières des professionnels? En utilisant une enquête longitudinale sur des avocats, les auteures évaluent l'incidence des postes et des aspirations en début de carrière sur les chances de bénéficier de services de mentorat. Elles mesurent les bénéfices du mentorat au moyen des récompenses de carrière intrinsèques et extrinsèques, pour découvrir que le contexte organisationnel et les attributs individuels constituent d'importants prédicteurs de qui bénéficiera de mentorat. Les professionnels ayant de multiples mentors se sont avérés les grands gagnants, en ce qu'ils obtiennent des récompenses de carrière plus importantes et plus diversifiées que ceux n'ayant pas de mentor.

This paper addresses two questions regarding mentoring: First, who is most likely to receive mentorship during their career? And second, how does mentorship shape the careers of professionals? Using a longitudinal survey of lawyers, we evaluate the impact of early career positions and aspirations on the chances for mentorship. We assess the benefits of mentorship across extrinsic and intrinsic career rewards. We find organizational context and individual attributes are important predictors of who receives mentorship. Professionals with multiple mentors were the big winners in that they obtain greater and more diverse career rewards over those with one or no mentors.
The rocks of Mars, from far and near
Authors: McSween Harry Y.
Published: January 2010

Abstract—The age, structure, composition, and petrogenesis of the martian lithosphere have been constrained by spacecraft imagery and remote sensing. How well do martian meteorites conform to expectations derived from this geologic context? Both data sets indicate a thick, extensive igneous crust formed very early in the planet's history. The composition of the ancient crust is predominantly basaltic, possibly andesitic in part, with sediments derived from volcanic rocks. Later plume eruptions produced igneous centers like Tharsis, the composition of which cannot be determined because of spectral obscuration by dust. Martian meteorites (except Allan Hills 84001) are inferred to have come from volcanic flows in Tharsis or Elysium, and thus are not petrologically representative of most of the martian surface. Remote‐sensing measurements cannot verify the fractional crystallization and assimilation that have been documented in meteorites, but subsurface magmatic processes are consistent with orbital imagery indicating thick crust and large, complex magma chambers beneath Tharsis volcanoes. Meteorite ejection ages are difficult to reconcile with plausible impact histories for Mars, and oversampling of young terrains suggests either that only coherent igneous rocks can survive the ejection process or that older surfaces cannot transmit the required shock waves. The mean density and moment of inertia calculated from spacecraft data are roughly consistent with the proportions and compositions of mantle and core estimated from martian meteorites. Thermal models predicting the absence of crustal recycling, and the chronology of the planetary magnetic field agree with conclusions from radiogenic isotopes and paleomagnetism in martian meteorites. However, lack of vigorous mantle convection, as inferred from meteorite geochemistry, seems inconsistent with their derivation from the Tharsis or Elysium plumes. Geological and meteoritic data provide conflicting information on the planet's volatile inventory and degassing history, but are apparently being reconciled in favor of a periodically wet Mars. Spacecraft measurements suggesting that rocks have been chemically weathered and have interacted with recycled saline groundwater are confirmed by weathering products and stable isotope fractionations in martian meteorites.
Experimental approach to generate shock veins in single crystal olivine by shear melting
Authors: Langenhorst Falko , POIRIER Jean‐Paul , DEUTSCH Alexander , HORNEMANN Ulrich
Published: January 2010

Abstract— A shock experiment has been devised to produce large shear in a single crystal sample of olivine. The recovered sample exhibits macroscopic shear faults resembling shock veins in ordinary chondrites. Examination with transmission electron microscopy reveals a high density of dislocations in the bulk olivine. The shear faults appear as thin veins containing small grains of olivine and pockets of glass. The microstructure and composition of the material in the veins point to fractional crystallization of a melt. An order of magnitude calculation is consistent with the idea that the veins were produced by shear melting. These results support the view that shock veins in meteorites are the result of shear heating rather than of pressure heterogeneities.
Thermoluminescence of forsterite and fused quartz as a candidate for the extended red emission
Authors: KOIKE C. , CHIHARA H. , KOIKE K. , NAKAGAWA M. , OKADA M. , TSUCHIYAMA A. , AOKI M. , AWATA T. , ATOBE K.
Published: January 2010

Abstract— We investigated thermoluminescence of silicates that are of interest in the interstellar and circumstellar medium after irradiation by γ‐rays and fast neutrons. The silicates are forsterite, orthoenstatite, olivine, quartz, and crystalline silicon. The irradiated enstatite shows weak and broad peaks at 545 and 760 nm. In contrast, irradiated bulk and powder samples of forsterite show strong and broad peaks at 640–660 nm. Although thermoluminescence of bulk forsterite is very similar to the extended red emission (ERE) of the Red Rectangle nebula, irradiated powdered forsterite did not reveal any sharp emission features over the broad band. Further, we investigated the possibility of thermoluminescence of crystalline silicon and found that luminescence scarcely appears. It is emphasized that the prominent carrier of ERE is forsterite and fused quartz.
Low‐energy helium ion irradiation‐induced amorphization and chemical changes in olivine: Insights for silicate dust evolution in the interstellar medium
Authors: CARREZ Philippe , DEMYK Karine , CORDIER Patrick , GENGEMBRE Léon , GRIMBLOT Jean , D'HENDECOURT Louis , JONES Anthony P. , LEROUX Hugues
Published: January 2010

Abstract— We present the results of irradiation experiments aimed at understanding the structural and chemical evolution of silicate grains in the interstellar medium. A series of He+ irradiation experiments have been performed on ultra‐thin olivine, (Mg,Fe)2SiO4, samples having a high surface/volume (S/V) ratio, comparable to the expected S/V ratio of interstellar dust. The energies and fluences of the helium ions used in this study have been chosen to simulate the irradiation of interstellar dust grains in supernovae shock waves. The samples were mainly studied using analytical transmission electron microscopy. Our results show that olivine is amorphized by low‐energy ion irradiation. Changes in composition are also observed. In particular, irradiation leads to a decrease of the atomic ratios O/Si and Mg/Si as determined by x‐ray photoelectron spectroscopy and by x‐ray energy dispersive spectroscopy. This chemical evolution is due to the differential sputtering of atoms near the surfaces. We also observe a reduction process resulting in the formation of metallic iron. The use of very thin samples emphasizes the role of surface/volume ratio and thus the importance of the particle size in the irradiation‐induced effects. These results allow us to account qualitatively for the observed properties of interstellar grains in different environments, that is, at different stages of their evolution: chemical and structural evolution in the interstellar medium, from olivine to pyroxene‐type and from crystalline to amorphous silicates, porosity of cometary grains as well as the formation of metallic inclusions in silicates.
Hosts of hydrogen in Allan Hills 84001: Evidence for hydrous martian salts in the oldest martian meteorite?
Authors: Eiler John M. , Kitchen Nami , Leshin Lauri , Strausberg Melissa
Published: January 2010

Abstract—The martian meteorite, Allan Hills (ALH) 84001, contains D‐rich hydrogen of plausible martian origin (Leshinet al., 1996). The phase identity of the host(s) of this hydrogen are not well known and could include organic matter (McKayet al., 1996), phlogopite (Brearley, 2000), glass (Mittlefehldt, 1994) and/or other unidentified components of this rock. Previous ion microprobe studies indicate that much of the hydrogen in ALH 84001 as texturally associated with concretions of nominally anhydrous carbonates, glass and oxides (Boctoret al., 1998; Sugiura and Hoshino, 2000). We examined the physical and chemical properties of the host(s) of this hydrogen by stepped pyrolysis of variously pre‐treated subsamples. A continuous‐flow method of water reduction and mass spectrometry (Eiler and Kitchen, 2001) was used to permit detailed study of the small amounts of this hydrogen‐poor sample available for study. We find that the host(s) of D‐rich hydrogen released from ALH 84001 at relatively low temperatures (˜500 °C) is soluble in orthophosphoric and dilute hydrochloric acids and undergoes near‐complete isotopic exchange with water within hours at temperatures of 200 to 300 °C. These characteristics are most consistent with the carrier phase(s) being a hydrous salt (e.g., carbonate, sulfate or halide); the thermal stability of this material is inconsistent with many examples of such minerals (e.g., gypsum) and instead suggests one or more relatively refractory hydrous carbonates (e.g., hydromagnesite). Hydrous salts (particularly hydrous carbonates) are common on the Earth only in evaporite, sabkha, and hydrocryogenic‐weathering environments; we suggest that much (if not all) of the “martian” hydrogen in ALH 84001 was introduced in analogous environments on or near the martian surface rather than through biological activity or hydrothermal alteration of silicates in the crust.
The relative formation ages of ferromagnesian chondrules inferred from their initial aluminum‐26/aluminum‐27 ratios
Authors: Mostefaoui Smail , Kita Noriko T. , Togashi Shigeko , Tachibana Shogo , Nagahara Hiroko , Morishita Yuichi
Published: January 2010

Abstract— We performed a systematic high‐precision secondary ion mass spectrometry 26Al‐26Mg isotopic study for 11 ferromagnesian chondrules from the highly unequilibrated ordinary chondrite Bishunpur (LL3.1). The chondrules are porphyritic and contain various amounts of olivine and pyroxene and interstitial plagioclase and/or glass. The chemical compositions of the chondrules vary from FeO‐poor to FeO‐rich. Eight chondrules show resolvable 26Mg excesses with a maximum δ26Mg of ˜1% in two chondrules. The initial 26Al/27Al ratios inferred for these chondrules range between (2.28 ± 0.73) × 10−5 to (0.45 ± 0.21) × 10−5. Assuming a homogeneous distribution of Al isotopes in the early solar system, this range corresponds to ages relative to CAIs between 0.7 ± 0.2 Ma and 2.4+0.7−0.4 Ma. The inferred total span of the chondrule formation ages is at least 1 Ma, which is too long to form chondrules by the X‐wind. The initial 26Al/27Al ratios of the chondrules are found to correlate with the proportion of olivine to pyroxene suggesting that olivine‐rich chondrules formed earlier than pyroxene‐rich chondrules. Though we do not have a completely satisfactory explanation of this correlation we tentatively interpret it as a result of evaporative loss of Si from earlier generations of chondrules followed by addition of Si to the precursors of later generation chondrules.
Hornblende alteration and fluid inclusions in Kärdla impact crater, Estonia: Evidence for impact‐induced hydrothermal activity
Authors: Kirsimäe Kalle , Suuroja Sten , Kirs Juho , Kärki Aulis , Polikarpus Maile , Puura Väino , Suuroja Kalle
Published: January 2010

Abstract— The well‐preserved Kärdla impact crater, on Hiiumaa Island, Estonia, is a 4 km diameter structure formed in a shallow Ordovician sea ˜455 Ma ago into a target composed of thin (˜150 m) unconsolidated sedimentary layer above a crystalline basement composed of migmatite granites, amphibolites and gneisses. The fractured and crushed amphibolites in the crater area are strongly altered and replaced with secondary chloritic minerals. The most intensive chloritization is found in permeable breccias and heavily shattered basement around and above the central uplift. Alteration is believed to have resulted from convective flow of hydrothermal fluids through the central areas of the crater. Chloritic mineral associations suggest formation temperatures of 100–300 °C, in agreement with the most frequent quartz fluid inclusion homogenization temperatures of 150–300 °C in allochthonous breccia. The rather low salinity of fluids in Kärdla crater (<13 wt% NaCleq) suggests that the hydrothermal system was recharged either by infiltration of meteoric waters from the crater rim walls raised above sea level after the impact, or by invasion of sea water through the disturbed sedimentary cover and fractured crystalline basement. The well‐developed hydrothermal system in Kärdla crater shows that the thermal history of the shock‐heated and uplifted rocks in the central crater area, rather than cooling of impact melt or suevite sheets, controlled the distribution and intensity of the impact‐induced hydrothermal processes.
A comparative study of opaque phases in Qingzhen (EH3) and MacAlpine Hills 88136 (EL3): Representatives of EH and EL parent bodies
Authors: Lin Y. , Goresy A. El
Published: January 2010

Abstract— Opaque minerals in the Qingzhen (EH3) and MacAlpine Hills (MAC) 88136 (EL3) enstatite chondrites were studied and compared with other EH and EL chondrites. All opaque minerals usually occur in multi‐sulfide‐metal clasts and nodules in the matrix between chondrules (El Goresy et al., 1988). The higher abundance of opaque minerals, the occurrence of niningerite and various alkali‐sulfides (e.g., caswellsilverite, phases A and B, djerfisherite) are diagnostic criteria for EH chondrites, while alabandite is characteristic for EL chondrites. In addition, EH chondrites are characterized by enrichments of Si in both kamacite and perryite, and alkali elements in sphalerite and chalcopyrite. The Mn contents of daubreelite and sphalerite are lower in EH than in EL chondrites. These are consistent with lower oxygen fugacity and higher H2S fugacity of EH than EL chondrites. In contrast, the discovery of sphalerite and Zn‐rich daubreelite in MAC 88136 indicates that their absence in EL6 chondrites is probably related to thermal metamorphism in the parent body.

Schreibersite microspherules are commonly enclosed in most sulfides in Qingzhen, but are absent in MAC 88136. They were once molten, and probably predated all sulfide host phases. The petrographic setting and chemical compositions of the sulfide hosts of the schreibersite microspherules in EH3 chondrites are consistent with formation by condensation. The earliest sulfide condensates oldhamite and niningerite occupy the interiors of the clasts and nodules, whereas the rims consist of troilite and djerfisherite. In addition, in Qingzhen, some other troilite, djerfisherite and sphalerite assemblages coexist with perryite. They were produced by sulfurization of metallic Fe‐Ni in the nebula. In MAC 88136, sulfurization of Si‐bearing Fe‐Ni metal is less pronounced, and it produced troilite, schreibersite and less abundant perryite. Two kinds of normal zoning and a reverse zoning trends of niningerite, and both normal and reverse zoning of sphalerite were found in clasts and nodules in Qingzhen. The coexistence of normal and reverse zoning profiles in niningerite grains in the same meteorite strongly suggests that they formed before accretion in the parent body, because an asteroidal metamorphic or an impact event in the parent body would have erased these contrasting profiles and destroyed the textural settings. In contrast, alabandite in MAC 88136 shows only normal zoning, with the FeS content decreasing to 9.3 mol% toward troilite, indicating very slow cooling at low temperature.
Mineralogy and petrology of melt rocks from the Popigai impact structure, Siberia
Authors: Whitehead J. , Grieve R. A. F. , Spray J. G.
Published: January 2010

Abstract—The late Eocene Popigai impact structure of Siberia comprises an approximately 0.5–1.5 km thick, ˜100 km diameter sequence of clast‐rich and clast‐poor andesitic to rhyolitic impact melt rocks and impact breccias, underlain by Archean to Proterozoic crystalline basement and Proterozoic to Phanerozoic sedimentary rocks. The fine‐grained to cryptocrystalline texture of the more melt‐rich rocks, despite their occurrence in bodies locally in excess of 800 m thick and 28 km long, suggests that the melt crystallized in response to (1) cooling by the clast load, and/or; (2) rapid nucleation on finely brecciated clasts, which have since been assimilated and/or; (3) crystallization enhanced by the relatively low water contents of the melts. Rapid crystallisation of the melt is indicated by the lack of zoning in minerals, the presence of glass, the lack of strain recovery features in clasts and the lack of evidence for fractionation in the major and trace elements, including the rare earth elements. Optical and analytical electron microscopy reveal that the previously reported division of the melt rocks into high‐ and low‐temperature variants based on hand sample appearance, or glass content, is not warranted.

Clasts within the melt‐rich rocks exhibit a wide range of shock metamorphic features, though they are not distributed in the impact melts in a systematic manner. This indicates that the melt‐rich rocks were well mixed during their formation, thus juxtaposing unshocked with shocked material. Injection of mesostasis melt into partially melted checkerboard plagioclase and orthopyroxene clasts also occurred during this mixing stage.
Molecular and isotopic analyses of Tagish Lake alkyl dicarboxylic acids
Authors: Pizzarello Sandra , Huang Yongsong
Published: January 2010

Abstract— The Tagish Lake meteorite soluble organic suite has a general composition that differs from those of both CI and CM chondrites. These differences suggest that distinct processes may have been involved in the formation of different groups of organics in meteorites. Tagish Lake alkyl dicarboxylic acids have a varied, abundant distribution and are, with carboxylated pyridines, the only compounds to have an occurrence comparable to that of the Murchison meteorite. This study has undertaken their molecular and isotopic characterization, with the aim to understand their origin and to gain insights into the evolutionary history of the meteorite parent body.

Tagish Lake alkyl dicarboxylic acids are present as a homologous series of saturated and unsaturated species with three‐ through ten‐carbon atom chain length. Linear saturated acids are predominant and show decreasing amounts with increasing chain length. A total of 44 of these compounds were detected with the most abundant, succinic acid, present at ˜40 nmol/g meteorite. Overall the molecular distribution of Tagish Lake dicarboxylic acids shows a remarkable compound‐to‐compound correspondence with those observed in the Murchison and Murray meteorites. In both Tagish Lake and Murchison, the imides of the more abundant dicarboxylic acids were also observed.

The hydrogen and carbon isotopic compositions of individual Tagish Lake dicarboxylic acids were determined and compared to those of the corresponding acids in the Murchison meteorite. All δD and δ13C values for Tagish Lake acids are positive and show a substantial isotopic enrichment. δD values vary from, approximately, +1120%o for succinic acid to +1530%o for methyl glutaric acid. δ13C values ranged from +12.6%o for methyl glutaric acid to +22.9%o for glutaric acid, with adipic acid having a significantly lower value (+5.5%o). Murchison dicarboxylic acid showed similar isotopic values: their δ513C values were generally higher by an average 17% and δD values were lower for succinic and glutaric acids, possibly due to contamination.

The molecular and isotopic data collected for these compounds restrict their possible origin to processes, either interstellar or of very cold nebular regions, that produced significant isotopic enrichments. Saturated or partially unsaturated nitriles and dinitriles appear to be good precursor candidates as their hydrolysis, upon water exposure, would produce dicarboxylic acids and other carboxylated species found in Tagish Lake. This evolutionary course could possibly include pre‐accretionary processes.
Amino acids in the Tagish Lake meteorite
Authors: Kminek G. , Botta O. , Glavin D. P. , Bada J. L.
Published: January 2010

Abstract— High‐performance liquid chromatography (HPLC) based amino acid analysis of a Tagish Lake meteorite sample recovered 3 months after the meteorite fell to Earth have revealed that the amino acid composition of Tagish Lake is strikingly different from that of the CM and CI carbonaceous chondrites. We found that the Tagish Lake meteorite contains only trace levels of amino acids (total abundance = 880 ppb), which is much lower than the total abundance of amino acids in the CI Orgueil (4100 ppb) and the CM Murchison (16 900 ppb). Because most of the same amino acids found in the Tagish Lake meteorite are also present in the Tagish Lake ice melt water, we conclude that the amino acids detected in the meteorite are terrestrial contamination. We found that the exposure of a sample of Murchison to cold water lead to a substantial reduction over a period of several weeks in the amount of amino acids that are not strongly bound to the meteorite matrix. However, strongly bound amino acids that are extracted by direct HCl hydrolysis are not affected by the leaching process. Thus even if there had been leaching of amino acids from our Tagish Lake meteorite sample during its 3 month residence in Tagish Lake ice and melt water, a Murchison type abundance of endogenous amino acids in the meteorite would have still been readily detectable. The low amino acid content of Tagish Lake indicates that this meteorite originated from a different type of parent body than the CM and CI chondrites. The parent body was apparently devoid of the reagents such as aldehyldes/ketones, HCN and ammonia needed for the effective abiotic synthesis of amino acids. Based on reflectance spectral measurements, Tagish Lake has been associated with P‐ or D‐type asteroids. If the Tagish Lake meteorite was indeed derived from these types of parent bodies, our understanding of these primitive asteroids needs to be reevaluated with respect to their potential inventory of biologically important organic compounds.
Itqiy: A study of noble gases and oxygen isotopes including its terrestrial age and a comparison with Zakłodzie
Authors: Patzer Andrea , Hill Dolores H. , Boynton William V. , Franke Luitgard , Schultz Ludolf , Jull A. J. Timothy , McHargue Lanny R. , Franchi Ian A.
Published: January 2010

Abstract— We report noble gas, oxygen isotope, 14C and 10Be data of Itqiy as well as noble gas, 14C and 10Be results for Zakłodzie. Both samples have been recently classified as anomalous enstatite meteorites and have been compared in terms of their mineralogy and chemical composition.

The composition of enstatite and kamacite and the occurrence of specific sulfide phases in Itqiy indicate it formed under similar reducing conditions to those postulated for enstatite chondrites. The new results now seem to point at a direct spatial link.

The noble gas record of Itqiy exhibits the presence of a trapped subsolar component, which is diagnostic for petrologic types 4–6 among enstatite chondrites. The concentration of radiogenic 4He is very low in Itqiy and indicates a recent thermal event. Its 21Ne cosmic‐ray exposure age is 30.1 ± 3.0 Ma and matches the most common age range of enstatite chondrites (mostly EL6 chondrites) but not that of Zakłodzie.

Itqiy's isotopic composition of oxygen is in good agreement with that observed in Zakłodzie as well as those found in enstatite meteorites suggesting an origin from a common oxygen pool. The noble gas results, on the other hand, give reason to believe that the origin and evolution of Itqiy and Zakłodzie are not directly connected.

Itqiy's terrestrial age of 5800 ± 500 years sheds crucial light on the uncertain circumstances of its recovery and proves that Itqiy is not a modern fall, whereas the 14C results from Zakłodzie suggest it hit Earth only recently.
Production of krypton and xenon isotopes in thick stony and iron targets isotropically irradiated with 1600 MeV protons
Authors: Gilabert E. , Lavielle B. , Michel R. , Leya I. , Neumann S. , Herpers U.
Published: January 2010

Abstract— Two spherical targets made of gabbro with a radius of 25 cm and of steel with a radius of 10 cm were irradiated isotropically with 1600 MeV protons at the SATURNE synchrotron at Laboratoire National Saturne (LNS)/CEN Saclay, in order to simulate the production of nuclides in meteorites induced by galactic cosmic‐ray protons in space. These experiments supply depth‐dependent production rate data for a wide range of radioactive and stable isotopes in up to 28 target elements. In this paper, we report results for 78Kr, 80–86Kr isotopes in Rb, Sr, Y and Zr and for 124Xe, 126Xe, 128–132Xe, 134Xe, 136Xe isotopes in Ba and La. Krypton and xenon concentrations have been measured at different depths in the spheres by using conventional mass spectrometry. Based on Monte‐Carlo techniques, theoretical production rates are calculated by folding depth‐dependent spectra of primary and secondary protons and secondary neutrons with the excitation functions of the relevant nuclear reactions. The comparison of the model calculation results with experimental data in the thick target experiments performed at LNS and previously at CERN have allowed adjustments of the poorly known excitation functions of neutron‐induced reactions. Thus, for the two experiments at SATURNE, excellent agreement is obtained between experimental and calculated production rates for most Kr and Xe isotopes in all investigated target elements. Only Xe production in Ba in the gabbro is underestimated by the calculations by ˜25%. This work validates the approach of the thin‐target model calculations of cosmogenic nuclide production rates in the attempt of modeling the interaction of galactic cosmic‐ray protons with stony and iron meteorites in space as well as with lunar samples.
Nitrogen in diamond‐free ureilite Allan Hills 78019: Clues to the origin of diamond in ureilites
Authors: Rai V. K. , Murty S. V. S. , Ott U.
Published: January 2010

Abstract— Nitrogen and noble gases were measured in a bulk sample and in acid‐resistant carbon‐rich residues of the ureilite Allan Hills (ALH) 78019 which has experienced low shock and is free of diamond. A small amount of amorphous carbon combusting at ≤500 °C carries most of the noble gases, while the major carbon phase consisting of large crystals of graphite combusts at ≥800 °C, and is almost noble‐gas free. Nitrogen on the other hand is present in both amorphous carbon and graphite, with different δ15N signatures of −21%o and +19%o, respectively, distinctly different from the very light nitrogen (about −100%o) of ureilite diamond. Amorphous carbon in ALH 78019 behaves similar to phase Q of chondrites with respect to noble gas release pattern, behavior towards oxidizing acids as well as nitrogen isotopic composition. In situ conversion of amorphous carbon or graphite to diamond through shock would require an isotopic fractionation of 8 to 12% for nitrogen favoring the light isotope, an unlikely proposition, posing a severe problem for the widely accepted shock origin of ureilite diamond.