bluuebunny/crossref_metadata_2025 huggingface dataset:
An Archean metamorphic core complex in the southern Slave Province: basement–cover structural relations between the Sleepy Dragon Complex and the Yellowknife Supergroup
Authors: James Donald T. , Mortensen James K.
Published: May 2010

Archean rocks in the Fenton Lake – Brown Lake area, southern Slave Province, are subdivided into two lithotectonic domains: a supracrustal domain, which consists mainly of the Archean Yellowknife Supergroup, and a gneiss–granite domain. The latter is composed of gneissic and metaigneous rocks of the Sleepy Dragon Complex, determined to be basement to the Yellowknife Supergroup, and granite plutons, including the 2641 ± 3.5 Ma Suse Lake granite and the 2583.5 ± 1 Ma Morose Granite. Volcanic rocks of the Cameron River Belt and greywacke–mudstone turbiditic metasedimentary rocks of the Burwash Formation constitute the supracrustal domain.A late Archean, amphibolite- to greenschist-facies, ductile to local brittle, high-strain zone separates the domains. Kinematic indicators demonstrate that the zone experienced two kinematically opposed episodes of displacement. The older episode involved pre- to synthermal peak thrusting of the supracrustal rocks over the gneiss–granite domain. Thrusting is kinematically and temporally consistent with late Archean, pre- to synthermal peak, regional contractional deformation. Structural and metamorphic relations and kinematic indicators suggest that thrusting and regional contraction were followed shortly by intrusion of the peraluminous Morose Granite and thereafter by a late syn- to post-thermal peak episode of extension, resulting in tectonic unroofing of the gneiss–granite domain.The sequential history of contraction and attendant regional metamorphism, granite intrusion, and, ultimately, extensional collapse, which is documented in the Archean rocks in the area, is a common feature of Phanerozoic collisional orogens. Moreover, the tectonic history of the gneiss–granite domain is broadly similar to the evolution of metamorphic core complexes in the North American Cordillera.
Structural evolution of Archean rocks in the western Wawa subprovince, Minnesota: refolding of precleavage nappes during D2 transpression
Authors: Jirsa M. A. , Southwick D. L. , Boerboom T. J.
Published: May 2010

Recent mapping in the western Wawa subprovince (the Vermilion district and its westward extensions in Minnesota) has identified a major, northeast-trending stratotectonic break, informally called the Leech Lake structural disconformity (LLSD), that separates two contrasting terranes. North of the LLSD are elongate, east-northeast-trending, fault-bounded panels of volcanic rocks, which are mostly north topping and homoclinal. South of the LLSD, large-scale, northwest-trending folds involve basaltic sequences that are stratigraphically overlain by thick sections of dacitic volcaniclastic and turbiditic rocks. However, the most prominent outcrop-scale deformational features are northeast-trending vertical folds and associated axial-planar cleavage related to transpression in D2. D1 minor folds and cleavage are rare.New field data indicate that the large folds in a predominantly sedimentary part of the southern terrane are early formed (D0–D1), and nappe-like. The precise form of the early folds is largely obscured by (i) superimposed folds and metamorphism contemporaneous with D2, (ii) faulting that began in D2 and outlasted folding, and (iii) emplacement of the Giants Range batholith and associated plutons. Nevertheless, the presence in the southern terrane of large areas of shallow-plunging, downward-facing rock sequences and the map pattern of rock units imply that a large south-verging, northwest-plunging thrust nappe (or nappes) antedated D2. Where the nappe lacked thick, rigid volcanic layers, accommodation to D2 transpression took the form of abundant Z folds. Much of the observed Z asymmetry of F2 folds may have resulted from compression and shear oblique to the trend of rock units. In contrast, early thrusts are inferred to have positioned volcanic units north of the LLSD such that their strike was nearly perpendicular to D2 compression, and therefore F2 folds did not develop extensively.
Late Archean tectono-magmatic evolution of the central Slave Province, Northwest Territories
Authors: King J. E. , Davis W. J. , Relf C.
Published: May 2010

An early tectono-stratigraphic and late plutonic assemblage are distinguished in the central part of the Archean Slave Province (Contwoyto Lake area) on the basis of their relationship to deformation and metamorphic episodes, and by geochemical characteristics. The older assemblage, which predates the onset of intense deformation and the thermal peak of metamorphism, comprises 2.68–2.65 Ga calc-alkaline volcanic and plutonic rocks, as well as extensive turbidites. The younger assemblage comprises ca. 2.61–2.58 Ga plutonic units that were emplaced during and after deformation (D,–D3) and the thermal peak of metamorphism. Compositions of the late plutonic units vary systematically with time of intrusion from an early, calc-alkaline, diorite – tonalite suite to late peraluminous granites. The early assemblage is interpreted to represent remnants of an island arc (or arcs) overlain by turbidites and accreted during D1 and D2. The later assemblage is interpreted as a product of late- to post-accretion, suprasubduction-zone magmatism and associated crustal melting.
Temporal distribution of granitoid plutonic rocks in the Archean Slave Province, northwest Canadian Shield
Authors: Breemen O. van , Davis W. J. , King J. E.
Published: May 2010

Granitoid rocks in the Slave Province consist of 4.0–2.8 Ga granitoid gneisses that predate the 2.71–2.65 Ga volcanic and turbiditic rocks of the Yellowknife Supergroup and 2.70–2.58 Ga granitoid plutons that intrude the Yellowknife Supergroup. U–Pb zircon ages and Nd and Pb isotopic data indicate that the older granitoids are restricted to the western part of the Slave Province. Granitoid gneisses in the eastern Slave Province, previously suspected to predate the Yellowknife Supergroup, are similar in age to the volcanic rocks.In this paper, the results of a detailed geochronological study of plutonic rocks of the Contwoyto Lake – Nose Lake area of the northcentral Slave Province are reviewed and integrated with the available age data base for plutonic rocks elsewhere in the Slave Province. The data indicate that the timing of the later (<2.7 Ga) plutonism is bimodal, consisting of two distinct magmatic periods separated by approximately 20 Ma of apparent magmatic quiescence. The first period was synvolcanic, dating from 2695 to 2650 Ma. The second period, during which more than 80% of the granitoids presently exposed in the Slave Province were intruded, lasted from 2625 to 2580 Ma, spanning the major Archean deformation events, Syndeformation granitoids, with ages between 2625 and 2595 Ma, are dominantly diorite and tonalité in composition. Late- to post-deformation granitoid rocks, with ages between 2605 and 2580 Ma, range in composition from megacrystic biotite granodiorite to two-mica granite. In general terms, the compositions of the granitoid plutons vary in time from dominantly metaluminous to more strongly peraluminous.Present data show no obvious regional age variation among the younger granitoid rocks across the province. This apparent absence of diachroneity has important implications for models interpreting the magmatism as having evolved in a continental-margin setting, because the extent of contemporaneous plutonism is more than 400 km across strike, considerably broader than in most Mesozoic continental-margin batholiths.
An isotopic study of the Island Lake Greenstone Belt, Manitoba: crustal evolution and progressive cratonization in the late Archean
Authors: Stevenson R. K. , Turek A.
Published: May 2010

Three new U–Pb zircon ages are reported for units within the Island Lake Greenstone Belt in northern Manitoba: the Jubilee Island dacite (2761 ± 12 Ma), the Chapin Bay tonalite (2748 ± 3 Ma), and the Wassagomach tonalité (2778 ± 5 Ma). Rb–Sr data suggest a mild metamorphic event about 2736 ± 67 Ma ago. Basalts within the basal Hayes River Group (2860–2900 Ma) appear to be derived from a time-averaged, Nd-depleted mantle with εNd values between +0.78 and +2.1. Lower εNd values (< +0.31) are found in volcanic and intrusive rocks of the same age, implying contamination by or remelting of preexisting crust to form the more felsic derivatives. εNd values of early tonalitic, trondhjemitic, and granitic plutons (2729–2900 Ma) decrease from +0.31 to −1.8 as the plutons become younger, and are indicative of a period of dominantly intracrustal recycling processes in the Island Lake region. It is suggested that this trend records the evolution of the Island Lake region through extensive intracrustal melting and recycling from a variably contaminated volcanic arc to a small mature craton. Uplift associated with the plutonism resulted in sedimentation of the Island Lake Group (2729–2749 Ma), followed by renewed granitic plutonism of the Late Intrusive Suite (2699–2729 Ma). εNd values of these units range from +3 to −3, suggesting renewed interaction of depleted mantle with the Island Lake crust. This possibly resulted from magmatism associated with the accretion of the Island Lake Terrane to the rest of the Superior Province.
Probabilistic framework for assessing liquefaction hazard at a given site in a specified exposure time using standard penetration testing
Authors: Juang C. Hsein , Ou Chang-Yu , Lu Chih-Chieh , Luo Zhe
Published: May 2010

This paper presents a probabilistic framework for assessing the liquefaction hazard at a given site in a given exposure time. Ten sites from different seismic-prone regions of the USA are studied to validate the developed probabilistic framework. Additionally, this framework is extended from the focus of liquefaction potential at a given soil element (or finite layer) to the concern of the whole soil column based on the concept of liquefaction potential index (LPI) proposed by Iwasaki and his co-workers. In this extended framework, the probability of surface manifestation of liquefaction at a given site subjected to all ground motions at all hazard levels in a given exposure time is determined. As an example to illustrate this probabilistic framework, the widely used, standard penetration test (SPT)-based method by Youd et al. is adopted as a building block in the framework. This framework is illustrated with examples and its versatility is demonstrated. Finally, the procedure for extending the developed framework to the evaluation of ground settlement is outlined.
Suppression of aberrant transient receptor potential cation channel, subfamily V, member 6 expression in hyperproliferative colonic crypts by dietary calcium
Authors: Peleg Sara , Sellin Joseph H. , Wang Yu , Freeman Michael R. , Umar Shahid
Published: May 2010

Dietary calcium is believed to reduce colon cancer risk, but the mechanism by which this occurs is poorly understood. Employing the Citrobacter rodentium -induced transmissible murine colonic hyperplasia (TMCH) model, we previously showed that a high-calcium diet (hCa) significantly abrogated hyperplasia in the distal colons of NIH-Swiss mice. Here, we explored the mechanism of dietary protection by hCa by analyzing the expression of genes involved in the regulation of Ca uptake/flux in the intestinal epithelium, including the Ca-sensing receptor, vitamin D receptor, Ca binding protein, and transient receptor potential cation channels, subfamily V, members 5 and 6 (TRPV5/6). Interestingly, while TRPV6 expression increased significantly during TMCH, the expression of the other gene products was unchanged. This elevated TRPV6 expression was significantly abrogated by a hCa diet. Immunofluorescence revealed apical membrane localization of TRPV6 in the normal colon, whereas during TMCH we observed intense apical pole and cytoplasmic staining along the entire longitudinal crypt axis, including the expanded proliferating zone. The hCa diet reversed this effect. In humans, overexpression of TRPV6 was associated with early-stage colon cancer, and in colon carcinoma cells, inhibition of TRPV6 expression by small interfering RNA inhibited their proliferation and induced apoptosis. TRPV6 small interfering RNA also diminished the transcriptional activity of the calcium-dependent nuclear factors in activated T cells. Thus the aberrant overexpression of TRPV6 contributes to colonic crypt hyperplasia in mice and to colon cancer cell proliferation in humans. Therefore, it is likely that suppression of TRPV6 by a hCa diet is required for its protective effects in the colon.
Central neuronal activation and pressor responses induced by circulating ANG II: role of the brain aldosterone-“ouabain” pathway
Authors: Huang Bing S. , Ahmadi Sara , Ahmad Monir , White Roselyn A. , Leenen Frans H. H.
Published: May 2010

An increase in plasma ANG II causes neuronal activation in hypothalamic nuclei and a slow pressor response, presumably by increasing sympathetic drive. We evaluated whether the activation of a neuromodulatory pathway, involving aldosterone and “ouabain,” is involved in these responses. In Wistar rats, the subcutaneous infusion of ANG II at 150 and 500 ng·kg−1·min−1 gradually increased blood pressure up to 60 mmHg at the highest dose. ANG II at 500 ng·kg−1·min−1 increased plasma ANG II by 4-fold, plasma aldosterone by 25-fold, and hypothalamic aldosterone by 3-fold. The intracerebroventricular infusion of an aldosterone synthase (AS) inhibitor prevented the ANG II-induced increase in hypothalamic aldosterone without affecting the increase in plasma aldosterone. Neuronal activity, as assessed by Fra-like immunoreactivity, increased transiently in the subfornical organ (SFO) but progressively in the paraventricular nucleus (PVN) and supraoptic nucleus (SON). The central infusion of the AS inhibitor or a mineralocorticoid receptor blocker markedly attenuated the ANG II-induced neuronal activation in the PVN but not in the SON. Pressor responses to ANG II at 150 ng·kg−1·min−1 were abolished by an intracerebroventricular infusion of the AS inhibitor. Pressor responses to ANG II at 500 ng·kg−1·min−1 were attenuated by the central infusion of the AS inhibitor or the mineralocorticoid receptor blocker by 70–80% and by Digibind (to bind “ouabain”) by 50%. These results suggest a novel central nervous system mechanism for the ANG II-induced slow pressor response, i.e., circulating ANG II activates the SFO, leading to the direct activation of the PVN and SON, and, in addition, via aldosterone-dependent amplifying mechanisms, causes sustained activation of the PVN and thereby hypertension.
The myocardial contractile response to physiological stress improves with high saturated fat feeding in heart failure
Authors: Berthiaume Jessica M. , Bray Molly S. , McElfresh Tracy A. , Chen Xiaoqin , Azam Salman , Young Martin E. , Hoit Brian D. , Chandler Margaret P.
Published: May 2010

Impaired myocardial contractile function is a hallmark of heart failure (HF), which may present under resting conditions and/or during physiological stress. Previous studies have reported that high fat feeding in mild to moderate HF/left ventricular (LV) dysfunction is associated with improved contractile function at baseline. The goal of this study was to determine whether myocardial function is compromised in response to physiological stress and to evaluate the global gene expression profile of rats fed high dietary fat after infarction. Male Wistar rats underwent ligation or sham surgery and were fed normal chow (NC; 10% kcal fat; Sham + NC and HF + NC groups) or high-fat chow (SAT; 60% kcal saturated fat; Sham + SAT and HF + SAT groups) for 8 wk. Myocardial contractile function was assessed using a Millar pressure-volume conductance catheter at baseline and during inferior vena caval occlusions and dobutamine stress. Steady-state indexes of systolic function, LV +dP/d tmax, stroke work, and maximal power were increased in the HF + SAT group versus the HF + NC group and reduced in the HF + NC group versus the Sham + NC group. Preload recruitable measures of contractility were decreased in HF + NC group but not in the HF + SAT group. β-Adrenergic responsiveness [change in LV +dP/d tmax and change in cardiac output with dobutamine (0–10 μg·kg−1·min−1)] was reduced in HF, but high fat feeding did not further impact the contractile reserve in HF. The contractile reserve was reduced by the high-fat diet in the Sham + SAT group. Microarray gene expression analysis revealed that the majority of significantly altered pathways identified contained multiple gene targets correspond to cell signaling pathways and energy metabolism. These findings suggest that high saturated fat improves myocardial function at rest and during physiological stress in infarcted hearts but may negatively impact the contractile reserve under nonpathological conditions. Furthermore, high fat feeding-induced alterations in gene expression related to energy metabolism and specific signaling pathways revealed promising targets through which high saturated fat potentially mediates cardioprotection in mild to moderate HF/LV dysfunction.
Increased inducible nitric oxide synthase and arginase II expression in heart failure: no net nitrite/nitrate production and protein S-nitrosylation
Authors: Heusch Philipp , Aker Stephanie , Boengler Kerstin , Deindl Elisabeth , van de Sand Anita , Klein Kristina , Rassaf Tienush , Konietzka Ina , Sewell Adrian , Menazza Sara , Canton Marcella , Heusch Gerd , Di Lisa Fabio , Schulz Rainer
Published: May 2010

Our objective was to address the balance of inducible nitric oxide (NO) synthase (iNOS) and arginase and their contribution to contractile dysfunction in heart failure (HF). Excessive NO formation is thought to contribute to contractile dysfunction; in macrophages, increased iNOS expression is associated with increased arginase expression, which competes with iNOS for arginine. With substrate limitation, iNOS may become uncoupled and produce reactive oxygen species (ROS). In rabbits, HF was induced by left ventricular (LV) pacing (400 beats/min) for 3 wk. iNOS mRNA [quantitative real-time PCR (qRT-PCR)] and protein expression (confocal microscopy) were detected, and arginase II expression was quantified with Western blot; serum arginine and myocardial nitrite and nitrate concentrations were determined by chemiluminescence, and protein S-nitrosylation with Western blot. Superoxide anions were quantified with dihydroethidine staining. HF rabbits had increased LV end-diastolic diameter [20.0 ± 0.5 (SE) vs. 17.2 ± 0.3 mm in sham] and decreased systolic fractional shortening (11.1 ± 1.4 vs. 30.6 ± 0.7% in sham; both P < 0.05). Myocardial iNOS mRNA and protein expression were increased, however, not associated with increased myocardial nitrite or nitrate concentrations or protein S-nitrosylation. The serum arginine concentration was decreased (124.3 ± 5.6 vs. 155.4 ± 12.0 μmol/l in sham; P < 0.05) at a time when cardiac arginase II expression was increased (0.06 ± 0.01 vs. 0.02 ± 0.01 arbitrary units in sham; P < 0.05). Inhibition of iNOS with 1400W attenuated superoxide anion formation and contractile dysfunction in failing hearts. Concomitant increases in iNOS and arginase expression result in unchanged NO species and protein S-nitrosylation; with substrate limitation, uncoupled iNOS produces superoxide anions and contributes to contractile dysfunction.
Thermal provocation to evaluate microvascular reactivity in human skin
Authors: Minson Christopher T.
Published: May 2010

With increased interest in predictive medicine, development of a relatively noninvasive technique that can improve prediction of major clinical outcomes has gained considerable attention. Current tests that are the target of critical evaluation, such as flow-mediated vasodilation of the brachial artery and pulse-wave velocity, are specific to the larger conduit vessels. However, evidence is mounting that functional changes in the microcirculation may be an early sign of globalized microvascular dysfunction. Thus development of a test of microvascular reactivity that could be used to evaluate cardiovascular risk or response to treatment is an exciting area of innovation. This mini-review is focused on tests of microvascular reactivity to thermal stimuli in the cutaneous circulation. The skin may prove to be an ideal site for evaluation of microvascular dysfunction due to its ease of access and growing evidence that changes in skin vascular reactivity may precede overt clinical signs of disease. Evaluation of the skin blood flow response to locally applied heat has already demonstrated prognostic utility, and the response to local cooling holds promise in patients in whom cutaneous disorders are present. Whether either of these tests can be used to predict cardiovascular morbidity or mortality in a clinical setting requires further evaluation.
Expiratory muscle loading increases intercostal muscle blood flow during leg exercise in healthy humans
Authors: Athanasopoulos Dimitris , Louvaris Zafeiris , Cherouveim Evgenia , Andrianopoulos Vasilis , Roussos Charis , Zakynthinos Spyros , Vogiatzis Ioannis
Published: May 2010

We investigated whether expiratory muscle loading induced by the application of expiratory flow limitation (EFL) during exercise in healthy subjects causes a reduction in quadriceps muscle blood flow in favor of the blood flow to the intercostal muscles. We hypothesized that, during exercise with EFL quadriceps muscle blood flow would be reduced, whereas intercostal muscle blood flow would be increased compared with exercise without EFL. We initially performed an incremental exercise test on eight healthy male subjects with a Starling resistor in the expiratory line limiting expiratory flow to ∼ 1 l/s to determine peak EFL exercise workload. On a different day, two constant-load exercise trials were performed in a balanced ordering sequence, during which subjects exercised with or without EFL at peak EFL exercise workload for 6 min. Intercostal (probe over the 7th intercostal space) and vastus lateralis muscle blood flow index (BFI) was calculated by near-infrared spectroscopy using indocyanine green, whereas cardiac output (CO) was measured by an impedance cardiography technique. At exercise termination, CO and stroke volume were not significantly different during exercise, with or without EFL (CO: 16.5 vs. 15.2 l/min, stroke volume: 104 vs. 107 ml/beat). Quadriceps muscle BFI during exercise with EFL (5.4 nM/s) was significantly ( P = 0.043) lower compared with exercise without EFL (7.6 nM/s), whereas intercostal muscle BFI during exercise with EFL (3.5 nM/s) was significantly ( P = 0.021) greater compared with that recorded during control exercise (0.4 nM/s). In conclusion, increased respiratory muscle loading during exercise in healthy humans causes an increase in blood flow to the intercostal muscles and a concomitant decrease in quadriceps muscle blood flow.
XRD total pattern fitting applied to study of microstructure of TiO2films
Authors: Matěj Z. , Kužel R. , Nichtová L.
Published: May 2010

New XRD total pattern fitting softwareMSTRUCTwas used to study the microstructure of magnetron-deposited TiO2thin films.MSTRUCTis an extension of theFOXprogram for structure determination from powder diffraction data.MSTRUCTmakes corrections for refraction and absorption, residual stress, and preferred orientation that are necessary for thin-film analysis using the parallel-beam geometry and an asymmetric detector scan with small angles of incidence. The program also corrects for crystallite size broadening in terms of log-normal distribution, two models of strain (phenomenological and dislocation models), as well as the influence of stacking faults in the most common cubic and hexagonal structures. The microstructure results obtained by this study show that during crystallization of the amorphous TiO2films, tensile stresses were generated resulting in anisotropic shifts of diffraction peaks. This was confirmed byin situcrystallization and direct stress measurements. The consideration of the stress effect in terms of the weighted Reuss-Voigt model improved the fits significantly. The stresses were found to depend systematically on the TiO2film thickness, and their values determined by total pattern fitting agree well with the values measured directly by XRD stress analysis.
In situ analysis of LiFePO4 batteries: Signal extraction by multivariate analysis
Authors: Rodriguez Mark A. , Van Benthem Mark H. , Ingersoll David , Vogel Sven C. , Reiche Helmut M.
Published: May 2010

The electrochemical reaction behavior of a commercial Li-ion battery (LiFePO4-based cathode, graphite-based anode) has been measured via in situ neutron diffraction. A multivariate analysis was successfully applied to the neutron diffraction data set facilitating in the determination of Li bearing phases participating in the electrochemical reaction in both the anode and cathode as a function of state-of-charge (SOC). The analysis resulted in quantified phase fraction values for LiFePO4 and FePO4 cathode compounds as well as the identification of staging behavior of Li6, Li12, Li24, and graphite phases in the anode. An additional Li-graphite phase has also been tentatively identified during electrochemical cycling as LiC48 at conditions of ∼5% to 15% SOC.
Nanoscale strain characterization in microelectronic materials using X-ray diffraction
Authors: Murray Conal E. , Ying A. J. , Polvino S. M. , Noyan I. C. , Cai Z.
Published: May 2010

The engineering of strained semiconductor materials represents an important aspect of the enhancement in CMOS device performance required for current and future generations of microelectronic technology. An understanding of the mechanical response of the Si channel regions and their environment is key to the prediction and design of device operation. Because of the complexity of the composite geometries associated with microelectronic circuitry, in situ characterization at a submicron resolution is necessary to verify the predicted strain distributions. Of the measurement techniques commonly used for strain characterization, synchrotron-based X-ray microbeam diffraction represents the best nondestructive method to provide spatially resolved information. The mapping of strain distributions in silicon-on-insulator (SOI) features induced by overlying silicon nitride structures and embedded heteroepitaxial features adjacent to SOI device channels are presented. The interaction regions of the SOI strain were observed to extend large distances from the SOI/stressor interfaces leading to significant overlap in the strain distributions at technically relevant dimensions. Experimental data were also compared to several mechanical models to assess their validity in predicting these strain distributions.
Dual detection X-ray fluorescence cryotomography and mapping on the model organism Daphnia magna
Authors: De Samber B. , Vanblaere S. , Evens R. , De Schamphelaere K. , Wellenreuther G. , Ridoutt F. , Silversmit G. , Schoonjans T. , Vekemans B. , Masschaele B. , Van Hoorebeke L. , Rickers K. , Falkenberg G. , Szaloki I. , Janssen C. , Vincze L.
Published: May 2010

Micro-X-ray fluorescence (μ-XRF) is a rapidly evolving analytical technique which allows visualising the trace level metal distributions within a specimen in an essentially nondestructive manner. At second generation synchrotron radiation sources, detection limits at the sub-parts per million level can be obtained with micrometer resolution, while at third generation sources the spatial resolution can be better than 100 nm. Consequently, the analysis of metals within biological systems using micro- and nano-X-ray fluorescence imaging is a quickly developing field of research. Since X-ray fluorescence is a scanning technique, the elemental distribution within the sample should not change during analysis. Biological samples pose challenges in this context due to their high water content. A dehydration procedure is commonly used for sample preparation enabling an analysis of the sample under ambient temperature conditions. Unfortunately, a potential change in elemental redistribution during the sample preparation is difficult to verify experimentally and therefore cannot be excluded completely. Creating a cryogenic sample environment allowing an analysis of the sample under cryogenic condition is an attractive alternative but not available on a routine basis. In this article, we make a comparison between the elemental distributions obtained by micro-SR-XRF within a chemically fixed and a cryogenically frozen Daphnia magna, a model organism to study the environmental impact of metals. In what follows, we explore the potential of a dual detector setup for investigating a full ecotoxicological experiment. Next to conventional 2D analysis, dual detector X-ray fluorescence cryotomography is illustrated and the potential of its coupling with laboratory absorption micro-CT for investigating the tissue-specific elemental distributions within this model organism is highlighted.
Internal stresses and textures of nanostructured alumina scales growing on polycrystalline Fe3Al alloy
Authors: Brito Pedro , Pinto Haroldo , Klaus Manuela , Genzel Christoph , Kaysser-Pyzalla Anke
Published: May 2010

The evolution of internal stresses in oxide scales growing on polycrystalline Fe3Al alloy in atmospheric air at 700 °C was determined using in situ energy-dispersive synchrotron X-ray diffraction. Ex situ texture analyses were performed after 5 h of oxidation at 700 °C. Under these conditions, the oxide-scale thickness, as determined by X-ray photoelectron spectroscopy, lies between 80 and 100 nm. The main phase present in the oxide scales is α-Al2O3, with minor quantities of metastable θ-Al2O3 detected in the first minutes of oxidation, as well as α-Fe2O3. α-Al2O3 grows with a weak (0001) fiber texture in the normal direction. During the initial stages of oxidation the scale develops, increasing levels of compressive stresses which later evolve to a steady state condition situated around −300 MPa.
Observations of shock-loaded tin and zirconium surfaces with single-pulse X-ray diffraction
Authors: Morgan Dane V. , Grover Mike , Macy Don , Madlener Mike , Stevens Gerald , Turley William D.
Published: May 2010

A single-pulse X-ray diffraction (XRD) diagnostic has been developed for the investigation of shocked material properties on a very short time scale. The diagnostic, which consists of a 37-stage Marx bank high-voltage pulse generator coupled to a needle-and-washer electron beam diode via coaxial cable, produces line-and-bremsstrahlung X-ray emission in a 40 ns pulse. The molybdenum anode produces 0.71 Å characteristic Kα lines used for diffraction. The X-ray beam passes through a pinhole collimator and is incident on the sample with an approximately 2 mm×5 mm spot and 1° full width at half maximum angular divergence. Coherent scattering from the sample produces a Debye-Scherrer diffraction pattern on an image plate located at 75 mm from the polycrystalline sample surface. An experimental study of the polycrystalline structures of zirconium and tin under high-pressure shock loading has been conducted with single-pulse XRD. The experimental targets were 0.1-mm-thick foils of zirconium and tin using 0.4-mm-thick vitreous carbon back windows for shock loading, and the shocks were produced by either Detasheet or PBX-9501 high explosives buffered by 1-mm-thick 6061-T6 aluminum. The diffraction patterns from both shocked zirconium and tin indicated a phase transition into a polymorphic mix of amorphous and new solid phases.
Certification of NIST Standard Reference Material 640d
Authors: Black David R. , Windover Donald , Henins Albert , Gil David , Filliben James , Cline James P.
Published: May 2010

The National Institute of Standards and Technology (NIST) certifies a variety of standard reference materials (SRM) to address specific aspects of instrument performance for divergent beam diffractometers. This paper describes SRM 640d, the fifth generation of this powder diffraction SRM, which is certified with respect to the lattice parameter. It consists of approximately 7.5 g silicon powder specially prepared to produce strain-free particles in a size range between 1 and 10 μm to eliminate size-broadening effects. It is typically used for calibrating powder diffractometers for the line position and line shape. A NIST built diffractometer, incorporating many advanced design features, was used to certify the lattice parameter of the silicon powder measured at 22.5 °C. Both type A, statistical, and type B, systematic, errors have been assigned to yield a certified value for the lattice parameter of a=0.543 159±0.000 020 nm.
Tests of microstructure reconstruction by forward modeling of high energy X-ray diffraction microscopy data
Authors: Hefferan C. M. , Li S. F. , Lind J. , Suter R. M.
Published: May 2010

Verification tests of the forward modeling technique for near-field high energy X-ray diffraction microscopy are conducted using two simulated microstructures containing uniformly distributed orientations. Comparison between the simulated and reconstructed microstructures is examined with consideration to both crystallographic orientation and spatial geometric accuracy. To probe the dependence of results on experimental parameters, simulated data sets use two different detector configurations and different simulated experimental protocols; in each case, the parameters mimic the experimental geometry used at Advanced Photon Source beamline 1-ID. Results indicate that element orientations are distinguishable to less than 0.1°, while spatial geometric accuracy is limited by the detector resolution.
Ovine Proinflammatory Cytokines Cross the Murine Blood-Brain Barrier by a Common Saturable Transport Mechanism
Authors: Threlkeld Steven W. , Lynch Jessica L. , Lynch Kristin M. , Sadowska Grazyna B. , Banks William A. , Stonestreet Barbara S.
Published: May 2010

Objectives: The cytokines interleukin (IL)-1β and IL-6 are modulators of the neuroimmune axis and have been implicated in neuronal cell death cascades after ischemia or infection. Previous work has shown that some cross-species conservation exists between human and rodent blood-brain barrier (BBB) transport systems. To further assess cross-species conservation of cytokine transport across the BBB, the current studies investigated permeability and inhibition of ovine IL-1β and IL-6 in the mouse. Methods: IL-1β or IL-6 was radioactively labeled with 131I and injected into the jugular vein at time zero. A subset of mice received 1 or 3 µg/mouse of an unlabeled ovine or murine cytokine (IL-1β or IL-6) to assess self- and/or cross-inhibition of transport. Permeability was assessed using multiple-regression analysis. Results: There was a significant linear relationship for both ovine 131I-IL-1β and 131I-IL-6 between brain/serum ratios and exposure time, indicating BBB permeability. Inclusion of 3 µg/mouse unlabeled ovine IL-1β or IL-6 significantly reduced the transport of ovine 131I-IL-1β or 131I-IL-6, respectively, across the BBB. Transport of both ovine 131I-IL-1β and 131I-IL-6 was significantly inhibited by 1 µg/mouse of murine IL-1β or IL-6, respectively. In contrast, 1 µg/mouse of unlabeled ovine IL-1β or IL-6 did not inhibit the transport of murine 131I-IL-1β or 131I-IL-6. Conclusions: Ovine IL-1β and IL-6 cross the mouse BBB by saturable transport. Inhibition of transport by murine homologs indicates that both species use the same transport mechanisms. Conversely, an inability of ovine cytokines to significantly inhibit the transport of murine cytokines indicates that mouse BBB has a lower affinity for ovine than murine cytokines. Knowledge of species-conserved BBB transport mechanisms may facilitate the development of novel animal models of central nervous system pathogenesis.
Ischemic Preconditioning Attenuates Morphological and Biochemical Changes in Hepatic Ischemia/Reperfusion in Rats
Authors: Jin Li-Ming , Liu Yuan-Xing , Zhou Lin , Xie Hai-Yang , Feng Xiao-Wen , Li Hui , Zheng Shu-Sen
Published: May 2010

Objective: Ischemic preconditioning (IPC) has been gradually introduced into clinical liver surgery and transplantation in recent years. However, the protective effects of IPC on hepatic warm ischemia/reperfusion (I/R) injury and the potential mechanisms involved are not fully understood. We aimed to evaluate whether the reduction of apoptotic sinusoidal endothelial cells (SECs), induced by IPC, contributes to its protective effect. Methods: Male Wistar rats were randomized into three experimental groups: the continuous clamping group underwent 60 min of 70% hepatic ischemia; the IPC group received 10 min ischemia followed by 10 min reperfusion prior to ischemia, and the sham control (sham) underwent a sham operation without ischemia. Hepatocyte and SEC apoptosis, liver necrotic areas and the levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST), hyaluronic acid, tumor necrosis factor, myeloperoxidase (MPO) and malondialdehyde were determined. Expression of cysteine-aspartic acid protease-3 (caspase-3) in hepatocytes and SECs was also investigated. Furthermore, the hepatic leukocyte infiltration was assessed by intravital fluorescence microscopy. Results: IPC exhibited a significant alleviation of their postischemic liver function. Serum AST, ALT and tissue MPO were significantly decreased by IPC, and the degree of hepatocyte and SEC apoptosis was significantly inhibited, as shown by the decreased numbers of adherent leukocytes. Conclusions: IPC attenuates hepatic I/R injury by the reduction of leukocyte infiltration, the reduction hepatic enzymatic leakage and the depression of apoptotic cells. SECs are more sensitive to apoptosis induced by warm I/R injury compared to hepatocytes.
A Novel External Esophageal Perfusion Model for Reflux-Associated Respiratory Symptoms
Authors: Li Qinzi , Kong Lingfei , Zhang Shuna , Zhong Zhaoshuang , Liu Xiaofeng , Wang Jinou , Kang Jian
Published: May 2010

Background and Objective: Gastroesophageal reflux disease (GERD) has been linked to a number of extra-esophageal symptoms and disorders, primarily in the respiratory tract. Current animal models of reflux esophagitis are adapted to diseases of the digestive system, rather than to reflux-associated respiratory symptoms. The aim of this study was to evaluate a novel external esophageal perfusion model to induce esophageal, tracheal and pneumonic histological injury similar to that associated with GERD. Methods: Twenty guinea pigs were randomized to the acid-treated or PBS-treated group. Esophageal catheters were used to perfuse the esophageal lumen of guinea pigs with hydrochloric acid containing 1 g/l pepsin or PBS for 14 days. The total cell number and cell differential counts in bronchoalveolar lavage fluid (BALF) were determined 24 h after the last perfusion. Histological changes in the esophageal, tracheal and pneumonic tissues were observed by hematoxylin-eosin staining. Results: The numbers of lymphocytes, eosinophils and total inflammatory cells in the BALF were significantly higher in acid-perfused than PBS-perfused animals. Histological evidence suggested esophageal and pneumonic inflammations were prominent in acid-treated animals. Conclusion: Repetitive, acid-perfused, esophageal events copied the animal models of reflux esophagitis, and elicited inflammatory responses in the airways and lungs of guinea pigs.
Feasibility and Efficiency of Indirect Lifestyle Interventions in Offspring of Type 2 Diabetic Patients
Authors: Nishigaki M. , Ota A. , Kusakabe T. , Matsuzaki C. , Taguchi S. , Kazuma K.
Published: May 2010

Introduction: Individuals genetically predisposed to type 2 diabetes represent an important target for preventive strategies. Genetic screening, based on information about individual genetic variants, will be possible technically, but translational research in this field is still insufficient. Family history thus represents a useful tool for detecting genetically high-risk populations in this post-genomic era. Objectives: The purpose of this pilot study was to investigate the feasibility and efficiency of indirect lifestyle interventions in offspring of type 2 diabetic patients. Methods: Offspring were recruited from 74 diabetic (Group 1) and 39 non-diabetic (Group 2, control group) patients. A lifestyle intervention was conducted by mail, a total of 3 times, every 3 months. Lifestyle related to diet and physical activity was assessed using a self-administered questionnaire. Results: Ten offspring of type 2 diabetic and 6 of non-diabetic patients participated in this study. Total energy intake decreased after 3 interventions in both of the groups (Group 1: 305 ± 228.8 kcal/day, p = 0.004; Group 2: 82 ± 65.6 kcal/day, p = 0.04); however, the effect of intervention was significantly greater in Group 1 compared to Group 2 (p = 0.021). Physical activity and other physical outcomes were stable in normal levels during the study period in both of the groups. Conclusions: The intervention program helped to reduce total energy intake in offspring of type 2 diabetic patients more than in the control group, but the acceptance rate of the intervention program was disappointingly low. Further consideration is required to access and motivate offspring to develop precautionary lifestyle principles.
Physiology of Pregnancy: Interaction between Mother and Child
Authors: Cetin Irene , Cardellicchio Manuela
Published: May 2010

In the last years evidence has shown how lifelong well-being strongly depends on intrauterine growth and development during intrauterine life. Fetal growth can achieve its full potential only with an adequate and fine-tuned interaction between mother, placenta and fetus. Several environmental and maternal factors like maternal diet, body composition and endocrine status may alter this delicate equilibrium. Moreover, placental function and metabolism contribute and regulate the availability of fetal nutrients. Changes in this complex mechanism may compromise the pregnancy outcome. In this chapter we wish to elucidate the physiologic mechanisms that regulate this interaction and how also little modifications may predispose to pathologies like intrauterine growth restriction and gestational diabetes with important consequences on fetal and adult health.
Islets of Langerhans Are Protected from Inflammatory Cell Recruitment during Reperfusion of Rat Pancreas Grafts
Authors: Preissler G. , Massberg S. , Eichhorn M.E. , Waldner H. , Loehe F. , Winter H. , Messmer K.
Published: May 2010

Background: Ischemia/reperfusion (I/R) injury plays a pivotal role in the development of graft pancreatitis, with ischemia time representing one of its crucial factors. However, it is unclear, whether exocrine and endocrine tissue experience similar inflammatory responses during pancreas transplantation (PTx). This study evaluated inflammatory susceptibilities of islets of Langerhans (ILH) and exocrine tissue after different preservation periods during early reperfusion. Methods: PTx was performed in rats following 2 h (2h-I) or 18 h (18h-I) preservation. Leukocyte-endothelial cell interactions (LEI) were analyzed in venules of acinar tissue and ILH in vivo over 2 h reperfusion. Nontransplanted animals served as controls. Tissue samples were analyzed by histomorphometry. Results: In exocrine venules leukocyte rolling predominated in the 2h-I group. In the 18h-I group, additionally, high numbers of adherent leukocytes were found. Histology revealed significant edema formation and leukocyte extravasation in the 18h-I group. Notably, LEI in postcapillary venules of ILH were significantly lower. Leukocyte rolling was only moderately enhanced and few leukocytes were found adherent. Histology revealed minor leukocyte extravasation. Conclusion: Ischemia time contributes decisively to the extent of the I/R-injury in PTx. However, ILH have a significantly lower susceptibility towards I/R, even when inflammatory reactions in adjacent exocrine tissue are evident.
Dermoscopy of Pigmented Poromas
Authors: Minagawa Akane , Koga Hiroshi
Published: May 2010

Background: To date, little is known about the dermoscopic features of pigmented poromas. Methods: Twelve cases of pigmented poromas examined by dermoscpy at the Department of Dermatology, Shinshu University Hospital (Matsumoto, Japan), between January 2000 and February 2009 were collected. Retrospectively, digital dermoscopic images were evaluated for the presence of dermoscopic structures. Results: Vascular structures were observed in 8 of 12 cases. Hairpin vessels were found in 3 cases. Most were elongated and irregularly shaped. Polymorphous vessels were observed in 3 cases, of which 2 showed combinations of dotted vessels and linear-irregular vessels and 1 combinations of hairpin vessels and glomerular vessels. Arborizing vessels were observed in 2 cases. Globule-like structures occurred in 7 cases. Globule-like structures and arborizing vessels coexisted in 2 cases. Comedo-like openings were observed in 3 cases, all of which were accompanied by hairpin vessels. Conclusions: Pigmented poromas mimic a number of skin tumors, including pigmented basal cell carcinomas, seborrheic keratosis and malignant melanoma, because they present various clinical, dermoscopic and histopathological features.
RGD-dependent binding of TP508 to integrin αvβ3 mediates cell adhesion and induction of nitric oxide
Authors: Rousseau Emma , Dreiza Catherine , Cheung-Flynn Joyce , Ramos Heidi , Ugarova Tatiana , Sheller Michael , Derkach Dmitry , Wadekar Subhagya , Perkins Kim
Published: May 2010

P508, a 23-amino acid RGD-containing synthetic peptide representing residues 508 to 530 of human prothrombin, mitigates the effects of endothelial dysfunction in ischaemic reperfusion injury. The objective of this study was to investigate whether TP508 binds to members of the integrin family of transmembrane receptors leading to nitric oxide synthesis. Immobilised TP508 supported adhesion of endothelial cells and αvβ3-expressing human embryonic kidney cells in a dose- and RGD-dependent manner. Soluble TP508 also inhibited cell adhesion to immobilised fibrinogen. The involvement of αvβ3 was verified with function-blocking antibodies and surface plasmon resonance studies. Adhesion of the cells to immobilised TP508 resulted in an induction of phosphorylated FAK and ERK1/2. In endothelial cells, TP508 treatment resulted in an induction of nitric oxide that could be inhibited by LM609, an αvβ3-specific, function-blocking monoclonal antibody. Finally, TP508 treatment of isolated rat aorta segments enhanced carbachol-induced vasorelaxation. These results suggest that TP508 elicits a potentially therapeutic effect through an RGD-dependent interaction with integrin αvβ3.