julilili42/papers huggingface dataset:
The AAA-type ATPase AtSKD1 contributes to vacuolar maintenance of Arabidopsis thaliana
2010-07-16

The vacuole is the most prominent organelle of plant cells. Despite its importance for many physiological and developmental aspects of plant life, little is known about its biogenesis and maintenance. Here we show that Arabidopsis plants expressing a dominant-negative version of the AAA (ATPase associated with various cellular activities) ATPase AtSKD1 (SUPPRESSOR OF K+ TRANSPORT GROWTH DEFECT1) under the control of the trichome-specific GLABRA2 (GL2) promoter exhibit normal vacuolar development in early stages of trichome development. Shortly after its formation, however, the large central vacuole is fragmented and finally disappears completely. Secretion assays with amylase fused to the vacuolar sorting signal of Sporamin show that dominant-negative AtSKD1 inhibits vacuolar trafficking of the reporter that is instead secreted. In addition, trichomes expressing dominant-negative AtSKD1 frequently contain multiple nuclei. Our results suggest that AtSKD1 contributes to vacuolar protein trafficking and thereby to the maintenance of the large central vacuole of plant cells, and might play a role in cell-cycle regulation.
Activity and PI3-kinase dependent trafficking of the intestinal anion exchanger downregulated in adenoma depend on its PDZ interaction and on lipid rafts
2010-07-16

The Cl/HCO 3 exchanger downregulated in adenoma (DRA) mediates electroneutral NaCl absorption in the intestine together with the apical Na/H exchanger NHE3. Lipid rafts (LR) modulate transport activity and are involved in phosphatidylinositol 3-kinase (PI3-kinase)-dependent trafficking of NHE3. Although DRA and NHE3 interact via PDZ adaptor proteins of the NHERF family, the role of LR and PDZ proteins in the regulation of DRA is unknown. We examined the association of DRA with LR using the nonionic detergent Triton X-100. DRA cofractionated with LR independently of its PDZ binding motif. Furthermore, DRA interacts with PDZK1, E3KARP, and IKEPP in LR, although their localization within lipid rafts is independent of DRA. Disruption of LR integrity resulted in the disappearance of DRA from LR, in a decrease of its surface expression and in a reduction of its activity. In HEK cells the inhibition of DRA by LR disruption was entirely dependent on the presence of the PDZ interaction motif. In addition, in Caco-2/BBE cells the inhibition by LR disruption was more pronounced in wild-type DRA than in mutated DRA (DRA-ETKFminus; lacking the PDZ binding motif)-expressing cells. Inhibition of PI3-kinase decreased the activity and the cell surface expression of wild-type DRA but not of DRA-ETKFminus; the partitioning into LR was unaffected. Furthermore, simultaneous inhibition of PI3-kinase and disruption of LR did not further decrease DRA activity and cell surface expression compared with LR disruption only. These results suggest that the activity of DRA depends on its LR association, on its PDZ interaction, and on PI3-kinase activity.
Millennial-scale variability in Red Sea circulation in response to Holocene insolation forcing
2010-07-16

In order to assess how insolation-driven climate change superimposed on sea level rise and millennial events influenced the Red Sea during the Holocene, we present new paleoceanographic records from two sediment cores to develop a comprehensive reconstruction of Holocene circulation dynamics in the basin. We show that the recovery of the planktonic foraminiferal fauna after the Younger Dryas was completed earlier in the northern than in the central Red Sea, implying significant changes in the hydrological balance of the northern Red Sea region during the deglaciation. In the early part of the Holocene, the environment of the Red Sea closely followed the development of the Indian summer monsoon and was dominated by a circulation mode similar to the current summer circulation, with low productivity throughout the central and northern Red Sea. The climatic signal during the late Holocene is dominated by a faunal transient event centered around 2.4 ka BP. Its timing corresponds to that of North Atlantic Bond event 2 and to a widespread regionally recorded dry period. This faunal transient is characterized by a more productive foraminiferal fauna and can be explained by an intensification of the winter circulation mode and high evaporation. The modern distribution pattern of planktonic foraminifera, reflecting the prevailing circulation system, was established after 1.7 ka BP.
The wide-field imager for IXO: status and future activities
2010-07-16

The Wide Field Imager (WFI) of the International X-ray Observatory (IXO) is an X-ray imaging spectrometer based on a&#13;\\nlarge monolithic DePFET (Depleted P-channel Field Effect Transistor) Active Pixel Sensor. Filling an area of&#13;\\n10 x 10 cm2 with a format of 1024 x 1024 pixels it will cover a field of view of 18 arcmin. The pixel size of&#13;\\n100 x 100 μm2 corresponds to a fivefold oversampling of the telescope's expected 5 arcsec point spread function. The&#13;\\nWFI's basic DePFET structure combines the functionalities of sensor and integrated amplifier with nearly Fano-limited&#13;\\nenergy resolution and high efficiency from 100 eV to 15 keV. The development of dedicated control and amplifier&#13;\\nASICs allows for high frame rates up to 1 kHz and flexible readout modes. Results obtained with representative&#13;\\nprototypes with a format of 256 x 256 pixels are presented.
Dark proteins disturb multichromophore coupling in tetrameric fluorescent proteins
2010-07-16

Abstract DsRed is representative of the tetrameric reef coral fluorescent proteins that constitute particularly interesting coupled multichromophoric systems. Either a green emitting or a red emitting chromophore can form within each of the monomers of the protein tetramer. Within the tetramers the chromophores are thought to be efficiently fluorescence resonance energy transfer (FRET) coupled. We have used spectrally resolved room temperature single molecule spectroscopy to address the issue of FRET and the role of dark proteins within single protein tetramers of DsRed and its variants DsRed2, DsRed_N42H and AG4. Our results show that for the majority of the tetramers the different chromophores are indeed effectively coupled. However, in a fraction of the tetramers that is characteristic for each DsRed variant analyzed, we observe a lack of effective FRET coupling. For these tetramers we invoke the existence of dark proteins lacking a functional chromophore that interrupt the energy transfer chain within the multichromophoric system. We show that these species lead to donor dequenching that strongly influences the bulk emission spectra. (© 2011 WILEY‐VCH Verlag GmbH &amp; Co. KGaA, Weinheim)
Management of perioperative stent thrombosis in patients undergoing surgery
2010-07-16

Surgery often requires the interruption of standard dual antiplatelet therapy using aspirin and clopidogrel. Here, we present three patients who underwent surgery and suffered from a perioperative stent thrombosis associated with premature discontinuation of dual antiplatelet therapy. Although there are missing evidence-based data and key guidelines, we suggest that patients who undergo surgery after coronary stenting may benefit from an individualized perioperative antiplatelet management strategy. After premature dual antiplatelet therapy discontinuation, when the bridging of the preoperative time interval with the use of a short acting intravenous glycoprotein (GP) IIb-IIIa inhibitor including a platelet function testing has been missed and a coronary stent thrombosis has occurred, the patients should be administered a GPIIb-IIIa inhibitor for 12&#x2013;24 hours, followed by aspirin for one day and a dual antiplatelet treatment after 24&#x2013;48 hours. Our patients benefited from this individualized practical approach.
Overview of an environment for automated electrical behavioural modelling using data-based methods
2010-07-18

This paper introduces an overview of an automated methodology for electrical black box behavioural modelling. The presented approach rests upon the transient simulation data of the in and output pins of an analogue or mixed signal circuit. This method extracts the magnitude and the phase information by measuring in- and output currents and voltages and creates a new electrical pin compatible black-box model which approximates the real electric behaviour of the original circuit. The behavioural model is made up of cross connected admittance models whose connections consist of complex functions which are approximated using Support Vector Machines. The electrical behavioural models have a speed-up factor up to 37x and an accuracy greater than 95% compared to the original circuit simulation. A special filter structure enables the modeling of frequency, amplitude and load dependent circuits. The electrical functioning of the methodology is shown by a passive second order Butterworth filter and a time variant and active charge pump circuit out of the automotive industry.
Prevalence and causative fungal species of tinea capitis among schoolchildren in Gabon
2010-07-19

Summary Tinea capitis is endemic among schoolchildren in tropical Africa. The objective was to determine the prevalence of symptomatic tinea capitis in schoolchildren in Gabon. A cross‐sectional study was conducted with 454 children aged 4–17 years, attending a rural school and an urban school. The diagnosis of tinea capitis was based on clinically manifest infection, direct microscopic examination using 20% potassium hydroxide (KOH) solution and fungal culture. Based on clinical examination, 105 (23.1%) of 454 children had tinea capitis. Seventy‐four (16.3%) children were positive by direct examination (KOH) and/or fungal culture. The prevalence of tinea capitis depended on the school studied and ranged from 20.4% in the urban school with a higher socioeconomic status to 26.3% in the rural school with a lower socioeconomic status. Similarly, the spectrum of causative species varied between the different schools. Taken the schools together, Trichophyton soudanense (29.4%) was the most prominent species, followed by Trichophyton tonsurans (27.9%) and Microsporum audouinii (25.0%). Clinically manifest tinea capitis is endemic among schoolchildren in the Lambaréné region in Gabon. The prevalence of tinea capitis and the causative species depended on the type of school that was investigated.
Assessment of the ductus venosus, tricuspid blood flow and the nasal bone in second‐trimester screening for trisomy 21
2010-07-19

Abstract Objective To examine the prevalence of reversed a‐wave in the ductus venosus, tricuspid regurgitation and absent nasal bone, in a second‐trimester population undergoing amniocentesis, after exclusion of major fetal defects and to estimate the performance in screening for trisomy 21 based on maternal age and these markers in a general population. Methods This was a retrospective study involving pregnancies undergoing amniocentesis due to increased risk for trisomy 21, mainly because of advanced maternal age. Before the invasive procedure, an ultrasound examination was carried out to exclude major fetal defects and to examine the ductus venosus, tricuspid blood flow and the presence of the fetal nasal bone. Modeling techniques were used based on 20 000 euploid pregnancies and 20 000 pregnancies with trisomy 21 to assess the screening performance in a general population. Results The study population consisted of 3613 euploid pregnancies and 35 cases with trisomy 21. In the euploid group, reversed flow in the ductus venosus, tricuspid regurgitation and an absent nasal bone was observed in 1.7%, 1.5% and 0.1% of cases, respectively. In the trisomic group, these markers were found in 14.3%, 11.4% and 14.3% of cases, respectively. For a 5% false‐positive rate, the detection rate in screening for trisomy 21, based on maternal age and either ductus venosus, tricuspid blood flow or nasal bone would be 33.8%, 32.4% or 31.4%, respectively. Screening by maternal age alone would detect 29.0% of the fetuses with trisomy 21. Receiver–operating characteristics curve analysis showed a slight but significant improvement in screening performance for trisomy 21 based on the inclusion of these markers. Conclusion Second‐trimester ultrasound screening for trisomy 21 based on maternal age with additional assessment of the ductus venosus, tricuspid blood flow and the fetal nasal bone in otherwise normal‐appearing fetuses is only marginally better than is screening by maternal age alone. Copyright © 2011 ISUOG. Published by John Wiley &amp; Sons, Ltd.
Isotopic Fractionation by Transverse Dispersion: Flow-through Microcosms and Reactive Transport Modeling Study
2010-07-20

Flow-through experiments were carried out to investigate the role of transverse dispersion on the isotopic behavior of an organic compound during conservative and bioreactive transport in a homogeneous porous medium. Ethylbenzene was selected as model contaminant and a mixture of labeled (perdeuterated) and light isotopologues was continuously injected in a quasi two-dimensional flow-through system. We observed a significant fractionation of ethylbenzene isotopologues during conservative transport at steady state. This effect was particularly pronounced at the plume fringe and contrasted with the common assumption that physical processes only provide a negligible contribution to isotope fractionation. Under the experimental steady state conditions, transverse hydrodynamic dispersion was the only process that could have caused the observed fractionation. Therefore, the measured isotope ratios at the outlet ports were interpreted with different parameterizations of the transverse dispersion coefficient. A nonlinear compound-specific parameterization showed the best agreement with the experimental data. Successively, bioreactive experiments were performed in two subsequent stages: a first oxic phase, involving a single strain of ethylbenzene degraders and a second phase with aerobic and anaerobic (i.e., ethylbenzene oxidation coupled to nitrate reduction) degradation. Significant fractionation through biodegradation occurred exclusively due to the metabolic activity of the anaerobic degraders. We performed analytical and numerical reactive transport simulations of the different experimental phases which confirmed that both the effects of physical processes (diffusion and dispersion) and microbially mediated reactions have to be considered to match the observed isotopic fractionation behavior.
DETECTION OF IRON IN PG1159 STARS
2010-07-20

Up to now, iron had not been found in any hydrogen-deficient (pre-) white dwarf of spectral type PG1159, despite intense searching in a number of objects. Consequently, an iron deficiency was claimed, in some cases at least 1 dex. The primary indicators were UV lines of Fe vii. Therefore, the search was confined to relatively cool PG1159 stars (Teff ≲150,000 K), otherwise Fe is too strongly ionized for a significant population of Fe vii. In this Letter, we announce the discovery of iron in the very hottest PG1159 stars (Teff = 150,000–200,000 K; RX J2117.1+3412, K 1−16, Longmore 4, NGC 246, H1504+65), based on the identification of the Fe x λλ979.3, 1022.9 lines in spectra obtained with the Far Ultraviolet Spectroscopic Explorer. Surprisingly, our analysis results in a solar iron abundance for these stars. It is conspicuous that they are among the most massive PG1159 stars (0.71–0.82 M☉), in contrast to those objects for which strongest Fe deficiency was claimed (0.53–0.56 M☉).
Keeping Memory Clear and Stable--The Contribution of Human Basal Ganglia and Prefrontal Cortex to Working Memory
2010-07-21

Successful remembering involves both hindering irrelevant information from entering working memory (WM) and actively maintaining relevant information online. Using a voxelwise lesion-behavior brain mapping approach in stroke patients, we observed that lesions of the left basal ganglia render WM susceptible to irrelevant information. Lesions of the right prefrontal cortex on the other hand make it difficult to keep more than a few items in WM. These findings support basal ganglia-prefrontal cortex models of WM whereby the basal ganglia play a gatekeeper role and allow only relevant information to enter prefrontal cortex where this information then is actively maintained in WM.
Effect ofCYP2B6,ABCB1, andCYP3A5Polymorphisms on Efavirenz Pharmacokinetics and Treatment Response: An AIDS Clinical Trials Group Study
2010-07-21

In AIDS Clinical Trials Group protocols 384, A5095, and A5097s, we characterized relationships between 22 polymorphisms in CYP2B6, ABCB1, and CYP3A5; plasma efavirenz exposure; and/or treatment responses. A stepwise logistic regression procedure selected polymorphisms associated with reduced drug clearance adjusted for body mass index and the composite CYP2B6 516/983 genotype. Relationships between selected polymorphisms and treatment responses were characterized by competing risk methodology. Association analyses involved 821 individuals (317 for pharmacokinetics and 643 for treatment response). Models that included CYP2B6 516/983 genotype best predicted pharmacokinetics. Slow-metabolizer genotypes were associated with increased central nervous system events among white participants and decreased virologic failure among black participants.
Downregulation of Angiogenin Transcript Levels and Inhibition of Colonic Carcinoma by Gum Arabic (Acacia senegal)
2010-07-21

Gum Arabic (GA), a nutrient from dried exudate of Acacia senegal, is widely used as emulsifier and stabilizer. It stimulates sodium and water absorption in diarrhea. This study explored the effects of GA in colonic tissue. Mice were treated with GA (10% wt/vol) in drinking water and gene array was performed. As GA modified several tumor-relevant genes, chemical cancerogenesis (intraperitoneal injection of 20 mg/kg 1,2-dimethylhydrazine followed by 3 cycles of 3% dextrane sodium sulphate in drinking water) was induced with or without GA treatment. Within 4 days, GA treatment decreased the colonic transcript levels of the angiogenetic factors angiogenin 1, angiogenin 3, and angiogenin 4 by 78 +/- 18%, 88 +/- 15%, and 92 +/- 13%, respectively (n = 5 each), and of further genes including CD38 antigen, aquaporin4, interleukin18, vav-3-oncogene, gamma(+)-amino acid transporter, sulfatase1, ubiquitinD, and chemokine ligand5. According to Western blotting, GA treatment similarly decreased angiogenin protein expression, and according to immunohistochemistry, it decreased ss-catenin expression. Chemical cancerogenesis resulted in multiple colonic tumors within 12 wk. GA treatment (10% wt/wt) in drinking water significantly decreased the number of tumors by 70%. The observations disclose a powerful anticarcinogenic effect of GA. The nutrient could thus be used for the prophylaxis against colon carcinoma particularly in individuals at enhanced risk.
Nanoscale SnO2 Hollow Spheres and Their Application as a Gas-Sensing Material
2010-07-22

The use of nanoscale SnO2 hollow spheres as a redox-active sensor is investigated. The underlying hollow spheres are prepared via a microemulsion approach and exhibit an outer diameter of about 15−25 nm, a highly crystalline shell with a thickness of 3−5 nm and an inner cavity of 10−20 nm in diameter. Subsequent to materials characterization based on SEM, STEM, TEM, IR, TG, BET, and XRD the applicability of as-prepared hollow spheres as highly porous layers in sensor operation is tested. Accordingly, SnO2 hollow spheres deposited on common sensor substrates show a good response to CO in a concentration range of 50 to 300 ppm. Moreover, the material turned out to be useful as a model system to study the conduction model of a porous layer with small grains.
Silver-Russell patients showing a broad range of ICR1 and ICR2 hypomethylation in different tissues
2010-07-22

In all known congenital imprinting disorders an association with aberrant methylation or mutations at specific loci was well established. However, several patients with transient neonatal diabetes mellitus (TNDM), Silver-Russell syndrome (SRS) and Beckwith-Wiedemann syndrome (BWS) exhibiting multilocus hypomethylation (MLH) have meanwhile been described. Whereas TNDM patients with MLH show clinical symptoms different from carriers with isolated 6q24 aberrations, MLH carriers diagnosed as BWS or SRS present only the syndrome-specific features. Interestingly, SRS and BWS patients with nearly identical MLH patterns in leukocytes have been identified. We now report on the molecular findings in DNA in three SRS patients with hypomethylation of both 11p15 imprinted control regions (ICRs) in leukocytes. One patient was a monozygotic (MZ) twin, another was a triplet. While the hypomethylation affected both oppositely imprinted 11p15 ICRs in leukocytes, in buccal swab DNA only the ICR1 hypomethylation was visible in two of our patients. In the non-affected MZ twin of one of these patients, aberrant methylation was also present in leukocytes but neither in buccal swab DNA nor in skin fibroblasts. Despite mutation screening of several factors involved in establishment and maintenance of methylation marks including ZFP57, MBD3, DNMT1 and DNMT3L the molecular clue for the ICR1/ICR2 hypomethylation in our patients remained unclear. Furthermore, the reason for the development of the specific SRS phenotype is not obvious. In conclusion, our data reflect the broad range of epimutations in SRS and illustrate that an extensive molecular and clinical characterization of patients is necessary.
Does the Type of Anonymity Matter? The Impact of Visualization on Information Sharing in Online Groups
2010-07-22

Groups who share information in computer-mediated settings often have to deal with the issue of anonymity. Previous research has shown that only people with a prosocial orientation--that is, those whose main interest is to add to the benefit of the group as a whole--are willing to share information in anonymous situations. The willingness to share information by those people with a proself orientation--that is, those who put more emphasis on their personal benefit--can be increased by providing photographs of the other group members. The information-sharing behavior of prosocials, however, suffers from such a deletion of anonymity. In an online experiment, we examined how information-sharing behavior of proselfs may be increased without negatively influencing the information-sharing behavior of prosocials in an online setting. It was shown that even proselfs share information if the group members are visualized in a homogeneous way, while prosocials' information-sharing behavior is not impaired by this visualization. In addition, the results suggest that people's perceived homogeneity of the online group, as well as the importance of the collective goal, are the underlying processes of this effect. These results have important practical implications for the design of online information-sharing settings.
How greater mouse-eared bats deal with ambiguous echoic scenes
2010-07-22

Echolocating bats have to assign the received echoes to the correct call that generated them. Failing to do so will result in the perception of virtual targets that are positioned where there is no actual target. The assignment of echoes to the emitted calls can be ambiguous especially if the pulse intervals between calls are short and kept constant. Here, we present first evidence that greater mouse-eared bats deal with ambiguity by changing the pulse interval more often, in particular by reducing the number of calls in the terminal group before landing. This strategy separates virtual targets from real ones according to their change in position. Real targets will always remain in a constant position, and virtual targets will jitter back and forth according to the change in the time interval.