julilili42/papers huggingface dataset:
Assessing measurement uncertainty of first‐order degradation rates in heterogeneous aquifers
2006-01-01

The principal idea of this paper is to simulate and evaluate the determination of first‐order degradation rate constants at heterogeneous contaminated sites under realistic conditions. First, a set of heterogeneous and contaminated synthetic aquifers is generated; second, the spreading of a solute plume subject to first‐order degradation is simulated. Third, this plume is investigated using “monitoring wells” placed along the presumed plume center line. Using only piezometric heads, concentrations and hydraulic conductivities obtained at these monitoring wells, first‐order degradation rate constants are calculated by methods typically used in field applications. The estimated rate constants are compared to the “real” value known from the simulations. This comparison is conducted for different degrees of heterogeneity, represented by lognormally distributed random conductivity fields. The results indicate that, with increasing degree of heterogeneity, “measured” degradation rate constants become uncertain with a high variability around the true constant. Measured rate constants tend to overestimate the true constant by up to one order of magnitude. A sensitivity analysis of the influences of source width, transport velocity, and dispersivity shows that (1) with increasing source width, measured rate constants decrease their relative error and increase their accuracy; (2) the choice of dispersivity can produce both over‐ and under‐estimation of the true rate constant; and (3) that large‐scale measurements of hydraulic conductivity yield better estimates of flow velocities as compared to local scale measurements. These results explain in part the high variability of field measured degradation rate constants reported in the literature.
Functional Coassembly of KCNQ4 with KCNE-ß- Subunits in Xenopus Oocytes
2006-01-01

The KCNQ gene family comprises voltage-gated potassium channels expressed in epithelial tissues (KCNQ1, KCNQ5), inner ear structures (KCNQ1, KCNQ4) and the brain (KCNQ2-5). KCNQ4 is expressed in inner and outer hair cells of the inner ear where it influences electrical excitability and cell survival. Accordingly, loss of function mutations of the KCNQ4 gene cause hearing loss in humans and functional k.o.-mice show progressive degeneration of outer hair cells (OHCs). However, characteristic electrophysiological features of the native KCNQ4- carried current I(K,n) in OHCs are not recapitulated by expression of KCNQ4 channels in heterologous expression systems. This might suggest modulation of KCNQ4 by interacting KCNE Beta-subunits, which are known to modify the properties of the closely related KCNQ1. The present study explored whether transcripts of the KCNE isoforms could be identified in OHC mRNA and whether the subunits modulate KCNQ4 function. RT-PCR indeed yielded transcripts of all five KCNEs in OHCs. Coexpression of the KCNE- Beta-subunits with human KCNQ4 in the Xenopus laevis oocyte expression system revealed that all KCNEs modulate KCNQ4 voltage dependence, protein stability and ion selectivity of hKCNQ4 in Xenopus oocytes. The deafness-associated Jervell and Lange- Nielsen syndrome (JLNS) mutation KCNE1(D76N) impairs KCNQ4-function whereas the Romano-Ward syndrome (RWS) mutant KCNE1(S74L), which shows normal hearing in patients, does not impair KCNQ4 channel function. In conclusion, KCNEs are presumably coexpressed with KCNQ4 in hair cells from the organ of Corti and might regulate KCNQ4 functional properties, effects that could be important under physiological and pathophysiological conditions.
Recurrence and transience of excited random walks on $Z^d$ and strips
2006-01-01

Abstract. We investigate excited random walks on Z d, d ≥ 1, and on planar strips Z × {0,1,..., L −1} which have a drift in a given direction. The strength of the drift may depend on a random i.i.d. environment and on the local time of the walk. We give exact criteria for recurrence and transience, thus generalizing results by Benjamini and Wilson for once-excited random walk on Z d and by the author for multi-excited random walk on Z. 1.
Invariant triple products
2006-01-01

It is shown that the space of invariant trilinear forms on smooth representations of a semisimple Lie group is finite dimensional if the group is a product of hyperbolic groups. Explicit upper bounds are given which are attained in the case of induced representations. Applications to automorphic coefficients are given.
Stimulation of Erythrocyte Phosphatidylserine Exposure by Paclitaxel
2006-01-01

Side effects of cytostatic treatment include development of anemia resulting from either decreased generation or accelerated clearance of circulating erythrocytes. Recent experiments revealed a novel kind of stress-induced erythrocyte death, i.e. eryptosis, which is characterized by enhanced cytosolic Ca(2+) levels, increased ceramide formation and exposure of phosphatidylserine at the cell surface. The present study explored whether cytostatic treatment with paclitaxel (Taxol) triggers eryptosis. Blood was drawn from cancer patients before and after infusion of 175 mg/m2 Taxol. The treatment significantly decreased the hematocrit and significantly increased the percentage of annexin-V-binding erythrocytes in vivo (by 37%). In vitro incubation of human erythrocytes with 10 microM paclitaxel again significantly increased annexin-V-binding (by 129%) and augmented the increase of annexin-V-binding following cellular stress. The enhanced phosphatidylserine exposure was not dependent on caspase-activity but paralleled by erythrocyte shrinkage, increase of cytosolic Ca(2+) activity, ceramide formation and activation of calpain. Phosphatidylserine exposure was similarly induced by docetaxel but not by carboplatin or doxorubicin. Moreover, eryptosis was triggered by the Ca(2+) ionophore ionomycin (10 microM). In mice, ionomycin-treated eryptotic erythrocytes were rapidly cleared from circulating blood and sequestrated into the spleen. In conclusion, our data strongly suggest that paclitaxel-induced anemia is at least partially due to induction of eryptosis.
Sea-level reversal during Termination II
2006-01-01

The termination of the penultimate glacial period (TII) shows both similarities and differences to the last termination (TI). Both terminations show significant cold reversals in the postglacial warming trend. TI consists of a continuously increasing sea-level trend, whereas TII may demonstrate a sea-level reduction midway through the termination. We present a new, continuous sea-level record for TII derived from Red Sea ?18O records that supports the existence of the TII sea-level reversal. The record gives an unprecedented look at the structure of the TII sea-level reversal, which consists of an early highstand lasting several millennia in duration, followed by a 30 ± 12 m to 40 ± 12 m reduction in sea level and a stillstand of several millennia, before the final sea-level rise to the marine oxygen isotope stage (MIS) 5e interglacial. We suggest that there is a link between the sea-level reversal and internal, millennial-scale variability in the climate system.
Atherosclerotic Disease: Whole-Body Cardiovascular Imaging with MR System with 32 Receiver Channels and Total-Body Surface Coil Technology—Initial Clinical Results
2006-01-01

In this prospective study, the feasibility of a comprehensive cardiovascular imaging protocol with a dedicated whole-body 1.5-T magnetic resonance (MR) imager with 32 receiver channels in 34 patients with peripheral arterial occlusive disease was evaluated. Informed consent and institutional review board approval were obtained. Three-dimensional MR angiographic data sets were acquired with adapted injection protocol. Cardiac functional imaging and delayed-enhancement imaging were performed, as were fluid-attenuated inversion-recovery imaging of the brain and time-of-flight MR angiography of the intracranial blood vessels. Sensitivity and specificity for depiction of significant vascular stenosis (> 70%) were 96%, with conventional digital subtraction angiography as the standard. Substantial microangiopathic tissue alterations (n = 4) and/or cerebral infarction (n = 4) were diagnosed in seven patients. In seven patients, subendocardial or transmural delayed enhancement was detected in corresponding regions, indicating prior myocardial infarction. Previously unknown findings diagnosed with MR imaging required midterm follow-up or therapy in 24 patients, whereas change of therapy or immediate treatment was necessary in three. For patients suspected of having systemic atherosclerotic disease, comprehensive risk assessment is feasible within 30 minutes.
Blood cell and plasma protein repellent properties of Star-PEG-modified surfaces
2006-01-01

The implantation of biomaterials, medical devices or prostheses can instigate a rejection response or initiate an undesirable adsorption of plasma proteins, as well as blood cells on the implant surface, thus triggering diverse defense mechanisms against the supposed pathologic invader. The extent of this inflammatory reaction depends in part on the biocompatibility of the used materials or coatings. Although adsorption and coagulation responses can appear during the total in vivo lifetime of the implant, they are initially and crucially formed within the first 2-4 weeks of implantation. This early phase is of decisive importance for the consecutive in-growth and healing process. The present study was intended to elucidate the effects of blood contact to surfaces modified with reactive six-arm star-shaped poly(ethylene glycol-stat-propylene glycol) pre-polymers (Star PEG). Taken together, for Star-PEG-covered substrates we could demonstrate a profound reduction of various blood-biomaterial interactions compared to non-coated substrates, indicating the promising potential of this material as future coating for biomaterials with blood contact.
Cystatin C – A Marker for Assessment of the Glomerular Filtration Rate in Patients with Cisplatin Chemotherapy
2006-01-01

&lt;i&gt;Background:&lt;/i&gt; Cystatin C has recently been proposed as an ideal marker for glomerular filtration rate (GFR). In this study, cystatin C serum levels were evaluated in comparison to serum creatinine concentrations and inulin clearances in patients with normal kidney function receiving cisplatin-based chemotherapy to assess the validity of cystatin C as an alternative endogenous marker of GFR. &lt;i&gt;Methods:&lt;/i&gt; Blood samples for the assessment of cystatin C, creatinine and inulin clearances were collected in patients before and after application of cisplatin in a clinical trial. Overall, 41 patients were included in the study, 35 of them were eligible receiving cisplatin in two different cisplatin-based chemotherapy schedules. &lt;i&gt;Results:&lt;/i&gt; A 21% increase of cystatin C serum levels was demonstrated in the placebo group after application of cisplatin. Analysis of inulin clearances revealed a 23% loss of inulin clearance in patients of the placebo arm. In contrast, significant changes could not be detected by analysis of serum creatinine levels. &lt;i&gt;Conclusions:&lt;/i&gt; Cystatin C represents a more sensitive clinical marker than serum creatinine for the early assessment of GFR damage caused by cisplatin. Changes in cystatin C serum concentrations correlate well to GFR decrease as measured by inulin clearance.
Importance and intensity of competition along a fertility gradient and across species
2006-01-01

Abstract Questions: 1. Can the importance and the intensity of competition vary independently along a nutrient gradient? 2. Are these variations species dependent? Location: Sub-alpine pastures of the northern French Alps. Methods: Competition intensity measures how much competition decreases the performances of an organism. Competition importance measures how much competition contributes to affect performance, among other processes (such as environmental stress or disturbance). Competition intensity and importance were measured on three co-occurring species: Festuca rubra, a perennial grass, and two forbs of contrasting basal area, Chaerophyllum hirsutum and Alchemilla xanthochlora. A neighbour removal experiment was performed on Festuca rubra in three sub-alpine grassland communities differing in fertility and on Chaerophyllum hirsutum and Alchemilla xanthochlora in the two more fertile of these communities. The importance of competition was quantified using an index proposed by Brooker et al. (2005). Results: Competition intensity and importance showed different patterns of variation along the fertility gradient for Festuca rubra: competition importance decreased with decreasing fertility whereas competition intensity did not change. The largest forb was the least affected by competition. Our results suggest that the importance of competition for all three species depended on their individual tolerance to low nutrient availability. Conclusions: 1. The distinction between the importance and the intensity of competition is helpful to explain conflicting results obtained on the variations of competition indices along productivity gradients. 2. The choice of a phytometer can affect the conclusions drawn from empirical studies. Abbreviations: Cimp = Competition importance; Cint = Competition intensity; DM = Dry matter production; NI = Nitrogen nutrition index; RNE = Relative neighbour effect; SLA = Specific leaf area.
Geochemical and Nd-Sr-Pb isotopic composition of Mesozoic volcanic rocks in the Songliao basin, NE China
2006-01-01

Mesozoic volcanic rocks exposed in the Songliao basin form a major part of the basin fill and are the important petroleum reservoir rocks. Petrogenesis of these volcanic rocks and their tectonic setting, however, are poorly understood due to lack of sufficient chemical and isotopic data. These volcanic rocks cover a wide compositional spectrum ranging from basaltic trachyandesite to high-silica rhyolite. They can be divided into two formations, the upper Jurassic Huoshiling formation (157-146 Ma) with dominant dark gray andesite and the lower Cretaceous Yingcheng formation (136-113 Ma) with dominant yellowish rhyolite. Compositionally, these rocks are peraluminous to metaluminous, high-K to medium-K, calc-alkaline. They are enriched in large-ion lithophile and light rare earth elements, depleted in high field strength and heavy rare earth elements, and commonly display negative anomalies of Nb, Ti and P. Initial 87Sr/86Sr ratios and initial εNd-values of these volcanic rocks range from 0.7034 to 0.7106 and from -3.4 to 5.3, respectively, and their δ18O values vary from 3.2‰ to 14.8‰. Initial 206Pb/204Pb and 207Pb/204Pb ratios have ranges of 17.65 to 18.22 and 15.52 to 15.57, respectively. The characteristic in Nd and Sr isotopic composition probably indicates a mixing of enriched MORB-like material and crustal component. Primary magmas for both the Jurassic and Cretaceous volcanic rocks could be derived from metasomatized enriched MORB-like sources, but the Cretaceous rhyolites commonly show crustal assimilation indicated by high initial 87Sr/86Sr ratios and low initial εNd values. Whether the volcanic rocks in the Songliao basin formed related either to the post-collisional setting of the Mongolia-Okhotsk suture or the subduction of the western Pacific plate remains to be discussed.
PGE<sub>2</sub>-induced Apoptotic Cell Death in K562 Human Leukaemia Cells
2006-01-01

Prostaglandin-E2 (PGE2) is known to trigger suicidal death of nucleated cells (apoptosis) and enucleated erythrocytes (eryptosis). In erythrocytes PGE2 induced suicidal cell death involves activation of nonselective cation channels leading to Ca2+ entry followed by cell shrinkage and triggering of Ca2+ sensitive cell membrane scrambling with phosphatidylserine (PS) exposure at the cell surface. The present study was performed to explore whether PGE2 induces apoptosis of nucleated cells similarly through cation channel activation and to possibly disclose the molecular identity of the cation channels involved. To this end, Ca2+ activity was estimated from Fluo3 fluorescence, mitochondrial potential from DePsipher fluorescence, phosphatidylserine exposure from annexin binding, caspase activation from caspAce fluorescence, cell volume from FACS forward scatter, and DNA fragmentation utilizing a photometric enzyme immunoassay. Stimulation of K562 human leukaemia cells with PGE2 (50 microM) increased cytosolic Ca2+ activity, decreased forward scatter, depolarized the mitochondrial potential, increased annexin binding, led to caspase activation and resulted in DNA fragmentation. Gene silencing of the Ca2+-permeable transient receptor potential cation channel TRPC7 significantly blunted PGE2-induced triggering of PS exposure and DNA fragmentation. In conclusion, K562 cells express Ca2+-permeable TRPC7 channels, which are activated by PGE2 and participate in the triggering of apoptosis.
Anomalous roughness evolution of rubrene thin films observed in real time during growth
2006-01-01

We study the growth and structure of thin films of the organic semiconductor rubrene during organic molecular beam deposition (OMBD) on silicon oxide in situ and in real time using X-ray scattering. Using in situ grazing incidence diffraction (GID) we find a small degree of local order but an otherwise largely disordered structure, consistent with out of plane scans. Monitoring the surface morphology in real time during growth, we find relatively smooth films (surface roughness sigma below approximately 15 A for thicknesses up to at least 600 A) and a significant delay before the onset of roughening. This anomalous roughening in the beginning and crossover to normal roughening later during growth may be related to conformational changes of rubrene in the early stages of growth.
Local delivery of soluble platelet collagen receptor glycoprotein VI inhibits thrombus formation in vivo
2006-01-01

Summary Platelet-mediated thrombus formation at the site of vascular injury isa major trigger for thrombo-ischemic complications after coronary interventions. The platelet collagen receptor glycoprotein VI (GPVI) plays a critical role in the initiation of arterial thrombus formation. Endothelial denudation of the right carotid artery in rabbits was induced through balloon injury. Subsequently, local delivery of soluble, dimeric fusion protein of GPVI (GPVI-Fc) (n=7) or control Fc (n=7) at the site of vascular injury was performed with a modified double-balloon drugdelivery catheter.Thrombus area within the injured carotid artery was quantified using a computer-assisted image analysis and was used as index of thrombus formation.The extent of thrombus formation was significantly reduced in GPVI-Fc- compared with control Fc-treated carotid arteries (relative thrombus area, GPVI-Fc vs. Fc: 9.3 ± 4.2 vs. 2.3 ± 1.7, p&lt;0.001). Local delivery of soluble GPVI resulted in reduced thrombus formation after catheter-induced vascular injury.These data suggest a selective pharmacological modulation of GPVI-collagen interactions to be important for controlling onset and progression of pathological arterial thrombosis, predominantly or even exclusively at sites of injured carotid arteries in the absence of systemic platelet therapy.
Extensive colonization of apples by smut anamorphs causes a new postharvest disorder
2006-01-01

Colonization of apples by ballistoconidium-forming fungi causes a new disorder, here named 'white haze'. White haze may occur in mild form in the field, but only becomes problematic after Ultra-Low Oxygen storage, and, therefore, may be considered as a postharvest disorder. All isolates, obtained using the spore-fall method, were morphologically identified as anamorphs of smut fungi belonging to the genus Tilletiopsis. Sequence analysis of the D1/D2 and the ITS domains of the rDNA revealed nine novel taxa scattered among the Exobasidiomycetidae (Ustilaginomycetes). Field experiments confirmed the erratic incidence of white haze over the years, and the development of the disorder seems to be enhanced at lower temperatures and a high relative humidity. Several scab fungicide treatments showed diminishing effects on the incidence of white haze.
'Almost there': the meaning of "almost"
2006-01-01

Modifiability by almost has been used as a test for the quantificational force of a DP without stating the meaning of almost explicitly. The aim of this paper is to give a semantics for almost applying across categories and to evaluate the validity of the almost test as a diagnosis for universal quantifiers. It is argued that almost is similar to other cross-categorial modifiers such as at least or exactly in referring to alternatives ordered on a scale. I propose that almost evaluates alternatives in which the modified expression is replaced by a value close by on the corresponding Horn scale. It is shown that a semantics for almost that refers to scalar alternatives derives the correct truth conditions for almost and explains selectional restrictions. At the same time, taking the semantics of almost seriously invalidates the almost test as a simple diagnosis for the nature of quantifiers.&#x0D;
Upregulation of HERG Channels by the Serum and Glucocorticoid Inducible Kinase Isoform SGK3
2006-01-01

Human ether-a-go-go (HERG) channels participate in the repolarization of the cardiac action potential. Loss of function mutations of HERG lead to delayed cardiac repolarization reflected by prolonged QT interval. HERG channels are regulated through a signaling cascade involving phosphatidylinositol 3 (PI3) kinase. Downstream targets of PI3 kinase include the serum and glucocorticoid inducible kinase (SGK) and protein kinase B (PKB) isoforms. The present study has been performed to explore whether SGK1 and SGK3 participate in the regulation of HERG channel activity. HERG was expressed in Xenopus oocytes with or without additional expression of SGK1 or SGK3. Chemiluminescence was employed to determine HERG plasma membrane protein abundance. Coexpression of SGK3 but not of SGK1 in Xenopus oocytes resulted in an increase of steady state current (I(HERG)) and enhanced cell membrane protein abundance without affecting gating kinetics of the channel. Replacement of serine by alanine at the two SGK consensus sites decreased I(HERG) but neither mutation abolished the stimulating effect of SGK3. In conclusion, SGK3 participates in the regulation of HERG by increasing HERG protein abundance in the plasma membrane and may thus modify the duration of the cardiac action potential.