julilili42/papers huggingface dataset:
On the Stability of Oligo(ethylene glycol) (C11EG6OMe) SAMs on Gold: Behavior at Elevated Temperature in Contact with Water
2011-02-22

In this study the temperature dependent confor-mation of hexa(ethylene glycol) self-assembling monolayers (SAMs) under aqueous conditions (in situ) is investigated. To this end characteristic absorption modes in the fingerprint region (1050-1500 cm(-1)) were monitored with real-time polarization modulation infrared spectroscopy. We found a temperature induced conformational change from predominantly helical to helical/all-trans. The process may be divided into two temperature regimes. Up to 40 °C the process is reversible after drying the monolayers in air and successive reimmersion in water, indicating a strong binding of the water molecules to the SAM. At higher temperatures, the conformational change is irreversible. Additionally, a rapid change to a larger mode width and a shift of the mode position to higher wavenumbers (blue-shift) at about 50 °C indicates structural changes caused by decreasing crystallinity of the SAM. While the conformational changes up to 40 °C are supposed to originate from an increased conformational freedom in combination with a stronger interaction with water molecules, the irreversibility and rapid change of mode characteristics at higher temperatures indicate chemical degradation. Complementary measurements in air show a fast and virtually complete reversibility up to 40 °C underlining the effect of the interaction of the ethylene glycol moiety with water. At temperatures above 50 °C modes indicating ester and formate groups appear, supporting the idea of chemical degeneration. Moreover, the temperature behavior is coverage dependent. At incomplete coverage the structural order of the SAM starts decreasing at lower temperatures. This study shows, that the conformational and structural change of hexa(ethylene glycol) SAMs at elevated temperature is an interplay of conformational changes of the SAM, its interaction with water and at higher temperatures its chemical degradation. Our experiments also underline the importance of the in situ analysis on the film structure.
Isolation, purification, crystallization and preliminary crystallographic studies of a chitinase fromCrocus vernus
2011-02-22

A chitinase has been isolated and purified from Crocus vernus corms. N-terminal amino-acid sequence analysis of the approximately 30 kDa protein showed 33% identity to narbonin, a seed protein from Vicia narbonensis L. The C. vernus chitinase was crystallized by the hanging-drop vapour-diffusion method using PEG 8000 as the main precipitant. The crystal belonged to the monoclinic space group C2, with unit-cell parameters a=172.3, b=37.1, c=126.4 Å, β=127° and two molecules per asymmetric unit. Diffraction data were collected to a resolution of 2.1 Å.
Urolithiasis Through the Ages: Data on More Than 200,000 Urinary Stone Analyses
2011-02-23

In what is to our knowledge the largest series of stone analysis reported to date we identified an age and gender relationship of stone formation and composition. Regional variations are common and underline the influence of living habits, diet and standard of medical care on urinary stone formation.
Plasmonic Coupling of Bow Tie Antennas with Ag Nanowire
2011-02-23

Ag nanowire with the receiving and transmitting Ag bow tie antenna pairs at its incident and emission ends was patterned on the SiO(2) substrate to realize an enhanced surface plasmon emission with a factor of 45 compared to the single Ag nanowire without antenna pairs. The receiving and transmitting bow tie antenna pairs enhanced the plasmon coupling and emission efficiencies of the Ag nanowire. And the maximum plasmon emission sensitively depended on the length of Ag nanowire, the arm length of bow tie antennas, and the incident angle of optical excitation. This enhanced plasmon emission was confirmed by finite-difference time-domain simulations and explored with analytical calculations using the impedance matching theory at optical frequency.
The Effects of Potassium Channel Opener P1075 on the Human Saphenous Vein and Human Internal Mammary Artery
2011-02-23

Because adrenergic contractions can contribute to the development of life-threatening spasm of coronary artery bypass graft, this study was performed to investigate the effect of adenosine 3-phosphate (ATP)-sensitive K channel (KATP) opener P1075 on contractions of isolated human saphenous vein (HSV) and human internal mammary artery (HIMA). Phasic contractions were evoked by electric field stimulation (20 Hz) and noradrenaline. The sustained contractions were evoked by phenylephrine. The presence of pore-forming Kir6.1 and Kir6.2 subunits of the KATP channels in the HIMA and only Kir6.2 in the HSV was confirmed immunomorphologically. P1075 inhibited in the HSV only, the electrical field stimulation contractions more strongly than noradrenaline contractions. In addition, the phenylephrine contractions of HSV were more sensitive to P1075 in comparison to those of HIMA. Glibenclamide, a KATP channel blocker antagonized the vasodilatation produced by P1075 in both grafts differently, because its effect was more prominent on the P1075-induced inhibition of contractions of HSV than of HIMA. We conclude that P1075 has a vasorelaxant effect and inhibited adrenergic contractions of the tested grafts. This effect is graft and vasoconstrictor selective and seems to be mediated by Kir6.1- and/or Kir6.2-containing KATP channels. Thus, P1075 can be considered as a potential drug in the prevention of graft spasm.
On the dynamics and collisional growth of planetesimals in\\n misaligned binary systems
2011-02-24

\\n Context. A large fraction of stars, including young T Tauri stars, are\\n observed to be members of binary or multiple systems. During the early stages of evolution\\n when the individual binary stars are surrounded by a gaseous and dusty disc, the binary\\n orbit plane and disc midplane may be mutually inclined. For the relatively thick\\n protostellar discs associated with T Tauri stars, it is expected that in this scenario the\\n disc will become mildly warped and undergo solid body precession around the angular\\n momentum vector of the binary system. At the present time it is unclear how solid bodies\\n such as planetesimals embedded in such a disc will evolve dynamically and affect the\\n formation of planets.\\n Aims. We investigate the dynamics of planetesimals embedded in gaseous\\n protoplanetary disc models which are perturbed by a binary companion on a circular,\\n inclined orbit. The main focus of this work is to examine the collisional velocities of\\n the planetesimals in order to determine the conditions under which planetesimal growth\\n through accretion is likely to occur, rather than erosion or catastrophic disruption. The\\n parameters we consider are the binary inclination, γF, the\\n binary separation, D, the disc mass, Md, and\\n planetesimal radius si. Our standard model\\n has D = 60 AU, γF = 45°, and a disc mass\\n equivalent to that of the minimum mass solar nebula model.\\n Methods. We use a 3-dimensional hydrodynamics code to model the\\n evolution of the disc. The planetesimals are treated as non-interacting test particles\\n which evolve because of gas drag, the gravitational force of the disc, and the\\n gravitational perturbation due to the companion star. We detect the moment when two\\n planetesimal orbits cross one another, and use these orbit crossing events to estimate the\\n collisional velocities of the planetesimals.\\n Results. For binary systems with modest inclination\\n (γF = 25°), we find that the disc gravity prevents the\\n planetesimal orbits from undergoing strong differential nodal precession (which they would\\n do in the absence of the disc), and forces the planetesimals to precess with the disc on\\n average. For planetesimals of different size, however, the orbit planes become modestly\\n inclined with respect to one another, leading to collisional velocities that would clearly\\n inhibit planetesimal growth. For larger binary inclinations\\n (γF = 45°), the Kozai effect is found to switch on, causing\\n the growth of very large relative velocities which are on the order of a few kilometres\\n per second. \\n Conclusions. We conclude that planet formation via the mutual accretion\\n of planetesimals is difficult to achieve in an inclined binary system with parameters\\n similar to those considered in this paper, although more distant stellar companions than\\n those we have studied should not present such a problem. For highly inclined systems in\\n which the Kozai effect switches on, the prospects for forming planets would appear to be\\n very remote indeed.\\n
Bulk electroporation and population calcium imaging in the adult mammalian retina
2011-02-24

The optical recording of light-evoked activity in populations of neurons in the mammalian retina offers several benefits over the use of multielectrode arrays. However, population imaging has been hindered by the effective loading of synthetic fluorescent indicators, especially in the mature tissue. We have therefore developed an electroporation method to label the complete ganglion cell layer of the adult mammalian retina. We optimized the protocol such that the retina recovers from electroporation and generates responses to visual stimuli. The method can be used with a diverse set of indicators with a range of affinities and emission wavelengths. It therefore can be combined with transgenic animals expressing fluorescent markers to target specific neuronal types. Importantly, the ganglion cell layer remains accessible for subsequent intracellular recording and morphological identification.
Likely Health Outcomes for Untreated Acute Febrile Illness in the Tropics in Decision and Economic Models; A Delphi Survey
2011-02-24

This study highlights the uncertainty around potential consequences of untreated malaria and bacterial illnesses. The lack of consensus on most parameters, the wide range of estimates, and the impact of variability in estimates on model outputs, demonstrate the importance of sensitivity analysis for decision models employing expert opinion. Results of such models should be interpreted cautiously. The diversity of expert opinion should be recognised when policy options are debated.
Clinical evaluation of MR temperature monitoring of laser‐induced thermotherapy in human liver using the proton‐resonance‐frequency method and predictive models of cell death
2011-02-24

Abstract Purpose: To assess the feasibility, precision, and accuracy of real‐time temperature mapping (TMap) during laser‐induced thermotherapy (LITT) for clinical practice in patients liver with a gradient echo (GRE) sequence using the proton resonance frequency (PRF) method. Materials and Methods: LITT was performed on 34 lesions in 18 patients with simultaneous real‐time visualization of relative temperature changes. Correlative contrast‐enhanced T1‐weighted magnetic resonance (MR) images of the liver were acquired after treatment using the same slice positions and angulations as TMap images acquired during LITT. For each slice, TMap and follow‐up images were registered for comparison. Afterwards, segmentation based on temperature (T) &gt;52°C on TMap and based on necrosis seen on follow‐up images was performed. These segmented structures were overlaid and divided into zones where the TMap was found to either over‐ or underestimate necrosis on the postcontrast images. Regions with T&gt;52°C after 20 minutes were defined as necrotic tissue based on data received from two different thermal dose models. Results: The average intersecting region of TMap and necrotic zone was 87% ± 5%, the overestimated 13% ± 4%, and the underestimated 13% ± 5%. Conclusion: This study demonstrates that MR temperature mapping appears reasonably capable of predicting tissue necrosis on the basis of indicating regions having greater temperatures than 52°C and could be used to monitor and adjust the thermal therapy appropriately during treatment. J. Magn. Reson. Imaging 2011;33:704–712. © 2011 Wiley‐Liss, Inc.
SGK, renal function and hypertension.
2011-02-24

Serum- and glucocorticoid-inducible kinase 1 (SGK1) is expressed following cell stress and exposure to a variety of hormones including glucocorticoids and mineralocorticoids. It is activated by insulin and growth factors via phosphatidylinositol-3-kinase and the 3-phosphoinositide-dependent kinase PDK1. SGK1 enhances the activity of a variety of ion channels such as ENaC, TRPV5, ROMK, KCNE1/KCNQ1 and ClCKb; carriers such as NHE3, NKCC2, NCC and SGLT1; as well as the Na+/K+-ATPase. SGK1 contributes to Na+ retention and K+ elimination of the kidney as well as mineralocorticoid stimulation of salt appetite. A certain SGK1 gene variant (combined polymorphisms in intron 6 [I6CC] and in exon 8 [E8CC/CT]) is associated with moderately enhanced blood pressure. The SGK1 gene variant has been shown to affect 3%-5% of whites and some 10% of Africans. The gene variant sensitizes the carriers to the hypertensive effects of hyperinsulinemia. Moreover, the SGK1 gene variant is associated with increased body mass index, presumably a result of enhanced SGLT1 activity with accelerated intestinal glucose absorption. Obesity predisposes the carriers of the gene variant to development of type 2 diabetes. Moreover, SGK1 stimulates coagulation. Thus, SGK1 may participate in the pathogenesis of metabolic syndrome or syndrome X, a condition characterized by the coincidence of essential hypertension, procoagulant state, obesity, insulin resistance and hyperinsulinemia.
German Venture Capitalists Investment Criteria Over Financing Stages
2011-02-24

This study empirically explores the respective importance of a variety of criteria relevant for the investment decision of German venture capitalists. We find that the relative importance of criteria varies with investment stages. In all stages, however, criteria in the personality of management category as well as the appreciation potential of the acquired equity stake are considered crucial. Irrelevant are various market characteristics, dividend potential, as well as the desired independence level of management. Thus, this analysis provides all participants in the venture capital (VC) process with a comprehensive understanding of the parameters underlying the VC investment decision in Germany.
Biomarker Candidates of Chlamydophila pneumoniae Proteins and Protein Fragments Identified by Affinity-Proteomics Using FTICR-MS and LC-MS/MS
2011-02-24

We report here an affinity-proteomics approach that combines 2D-gel electrophoresis and immunoblotting with high performance mass spectrometry to the identification of both full length protein antigens and antigenic fragments of Chlamydophila pneumoniae (C. pneumoniae). The present affinity-mass spectrometry approach effectively utilized high resolution FTICR mass spectrometry and LC-tandem-MS for protein identification, and enabled the identification of several new highly antigenic C. pneumoniae proteins that were not hitherto reported or previously detected only in other Chlamydia species, such as Chlamydia trachomatis. Moreover, high resolution affinity-MS provided the identification of several neo-antigenic protein fragments containing N- and C-terminal, and central domains such as fragments of the membrane protein Pmp21 and the secreted chlamydial proteasome-like factor (Cpaf), representing specific biomarker candidates.
Corporate Acquisition Through Bankruptcy Auctions
2011-02-24

The objective of this case is to teach and initiate a class discussion about how to find potential buyers for a bankrupt firm. The discussion is facilitated by a real world case example that focuses on strategies based on use of databases such as D&amp;B or Sorkins, trade associations networks, trade magazines, information on recent industry acquisitions, and use of private equity groups. Issues relevant to optimal design of a bankruptcy auction and the required bidding process for achieving an optimal sale price are also addressed.
Detection of Cerebral Reorganization Induced by Real-Time fMRI Feedback Training of Insula Activation
2011-02-25

Background. Studies with real-time functional magnetic resonance imaging (fMRI) demonstrate that humans volitionally regulate hemodynamic signals from circumscribed regions of the brain, leading to area-specific behavioral consequences. Methods to better determine the nature of dynamic functional interactions between different brain regions and plasticity due to self-regulation training are still in development. Objective. The authors investigated changes in brain states while training 6 healthy participants to self-regulate insular cortex by real-time fMRI feedback. Methods. The authors used multivariate pattern analysis to observe spatial pattern changes and a multivariate Granger causality model to show changes in temporal interactions in multiple brain areas over the course of 5 repeated scans per subject during positive and negative emotional imagery with feedback about the level of insular activation. Results. Feedback training leads to more spatially focused recruitment of areas relevant for learning and emotion. Effective connectivity analysis reveals that initial training is associated with an increase in network density; further training “prunes” presumably redundant connections and “strengthens” relevant connections. Conclusions. The authors demonstrate the application of multivariate methods for assessing cerebral reorganization during the learning of volitional control of local brain activity. The findings provide insight into mechanisms of training-induced learning techniques for rehabilitation. The authors anticipate that future studies, specifically designed with this hypothesis in mind, may be able to construct a universal index of cerebral reorganization during skill learning based on multiple similar criteria across various skilled tasks. These techniques may be able to discern recovery from compensation, dose–response curves related to training, and ways to determine whether rehabilitation training is actively engaging necessary networks.
HESS J1943+213: a candidate extreme BL Lacertae object
2011-02-25

\\n Context. The H.E.S.S. Cherenkov telescope array has been surveying the Galactic plane for new VHE (&gt;100 GeV) gamma-ray sources.\\n Aims. We report on a newly detected point-like source, HESS J1943+213. This source coincides with an unidentified hard X-ray source IGR J19443+2117, which was proposed to have radio and infrared counterparts.\\n Methods. We combine new H.E.S.S., Fermi/LAT and Nançay Radio Telescope observations with pre-existing non-simultaneous multi-wavelength observations of IGR J19443+2117 and discuss the likely source associations as well as the interpretation as an active galactic nucleus, a gamma-ray binary or a pulsar wind nebula.\\n Results. HESS J1943+213 is detected at the significance level of 7.9σ (post-trials) at RA(J2000) = \\\\hbox{ }, Dec(J2000) = \\\\hbox{ }. The source has a soft spectrum with photon index Γ = 3.1 ± 0.3stat ± 0.2sys and a flux above 470 GeV of (1.3 ± 0.2stat ± 0.3sys) × 10-12 cm-2 s-1. There is no Fermi/LAT counterpart down to a flux limit of 6 × 10-9 cm-2 s-1 in the 0.1–100 GeV energy range (95% confidence upper limit calculated for an assumed power-law model with a photon index Γ = 2.0). The data from radio to VHE gamma-rays do not show any significant variability. \\n Conclusions. The lack of a massive stellar counterpart disfavors the binary hypothesis, while the soft VHE spectrum would be very unusual in case of a pulsar wind nebula. In addition, the distance estimates for Galactic counterparts places them outside of the Milky Way. All available observations favor an interpretation as an extreme, high-frequency peaked BL Lac object with a redshift z &gt; 0.14. This would be the first time a blazar is detected serendipitously from ground-based VHE observations, and the first VHE AGN detected in the Galactic Plane.\\n
Reversible Photoswitchable DRONPA‐s Monitors Nucleocytoplasmic Transport of an RNA‐Binding Protein in Transgenic Plants
2011-02-26

Fluorescent reporter proteins that allow repeated switching between a fluorescent and a non‐fluorescent state are novel tools for monitoring intracellular protein trafficking. A codon‐optimized variant of the reversibly photoswitchable fluorescent protein DRONPA was designed for the use in transgenic Arabidopsis plants. Its codon usage is also well adapted to the mammalian codon usage. The synthetic protein, DRONPA‐s, shows photochemical properties and switching behavior comparable to that of the original DRONPA from Pectiniidae both in vitro and in vivo . DRONPA‐s fused to the RNA‐binding protein At GRP7 ( Arabidopsis thaliana glycine‐rich RNA‐binding protein 7) under control of the endogenous AtGRP7 promoter localizes to cytoplasm, nucleoplasm and nucleolus of transgenic Arabidopsis plants. To monitor the intracellular transport dynamics of At GRP7‐DRONPA‐s, we set up a single‐molecule sensitive confocal fluorescence microscope. Fluorescence recovery after selective photoswitching experiments revealed that At GRP7‐DRONPA‐s reaches the nucleus by carrier‐mediated transport. Furthermore, photoactivation experiments showed that At GRP7‐DRONPA‐s is exported from the nucleus. Thus, At GRP7 is a nucleocytoplasmic shuttling protein. Our results show that the fluorescent marker DRONPA‐s is a versatile tool to track protein transport dynamics in stably transformed plants.
Alexander's law during high-acceleration head rotations in humans
2011-02-26

Alexander's law states that the amplitude of the spontaneous nystagmus grows with increasing gaze in the direction of the fast phase. Using the search-coil method we employed head impulses at various eye-in-orbit azimuth angles to test (i) whether the normal vestibulo-ocular reflex (VOR) in the behaviorally relevant high-frequency range has intrinsic properties that could account for Alexander's law and (ii) whether such properties can also be shown in patients with unilateral vestibulopathy. We showed that the gain of the VOR remained unaffected by eye-in-orbit position in contols and in patients, both on ipsilesional and contralesional stimuli. These findings suggest that eye-in-orbit position does not directly modulate the activity in VOR pathways, neither during unbalanced but reciprocal (in controls), nor during unbalanced and nonreciprocal natural vestibular stimulation (in patients).
New computerized fetal heart rate analysis for surveillance of intrauterine growth restriction
2011-02-28

Abstract Objective Decreased fetal heart rate variability is associated with higher perinatal morbidity and mortality in intrauterine growth restriction (IUGR). This study used a new method [phase‐rectified signal averaging (PRSA)] to calculate acceleration‐ and deceleration‐related fluctuations of the fetal heart rate. Method Cardiotocograms from 74 growth‐restricted and 161 normal fetuses were included. Both groups were matched for gestational age. The transformed PRSA signal was quantified by the acceleration‐related parameter‐averaged acceleration capacity (AAC) and compared to the standard short‐term variation (STV). Mann‐Whitney test and receiver operator characteristic (ROC) curves were used for statistical analysis. Results For AAC, the median values of the IUGR group and control group were 1.97 bpm [interquartile range (IQR): 1.66–2.23] and 2.49 bpm (IQR: 2.24–2.72), respectively. For STV, these values were 5.44 ms (IQR: 4.49–7.38) and 7.79 ms (IQR: 6.35–9.66), respectively. The area under the ROC curve was 81.4% for AAC and 70.5% for STV. Conclusion The results of AAC are in both groups comparable to STV. Longitudinal studies are needed to investigate the association of AAC with the clinical outcome of the newborn. Copyright © 2011 John Wiley &amp; Sons, Ltd.