julilili42/papers huggingface dataset:
Ptychography: a novel phase retrieval technique, advantages and its application
2011-05-21

This paper is intended to introduce ptychography, a novel and very promising phase retrieval technique. It is based on the lens-less recording of a series of diffraction patterns caused by coherent object illumination. In the visible region of light, ptychography has successfully been implemented for visible light microscopy and optical metrology. Ptychography has also successfully been applied to X-ray microscopy where it is difficult to manufacture good quality lenses and where, at high X-ray energies, absorption contrast is low but where phase contrast is significant. In the course of this paper theoretical fundamentals of ptychography are explained, advantages in comparison to traditional optical techniques are represented and applications are shown.
OBSERVATIONS OF THE YOUNG SUPERNOVA REMNANT RX J1713.7–3946 WITH THEFERMILARGE AREA TELESCOPE
2011-05-23

We present observations of the young supernova remnant (SNR) RX J1713.7–3946 with the Fermi Large Area Telescope (LAT). We clearly detect a source positionally coincident with the SNR. The source is extended with a best-fit extension of 0fdg55 ± 0fdg04 matching the size of the non-thermal X-ray and TeV gamma-ray emission from the remnant. The positional coincidence and the matching extended emission allow us to identify the LAT source with SNR RX J1713.7–3946. The spectrum of the source can be described by a very hard power law with a photon index of Γ = 1.5 ± 0.1 that coincides in normalization with the steeper H.E.S.S.-detected gamma-ray spectrum at higher energies. The broadband gamma-ray emission is consistent with a leptonic origin as the dominant mechanism for the gamma-ray emission.
The on-line processing of socio-emotional information in prototypical scenarios: inferences from brain potentials
2011-05-23

Little is known about the time course of the mechanisms involved in the on-line processing of socio-emotional information. We used event-related brain potentials (ERPs) to investigate this issue using vignettes that described prototypical, social scenarios. An initial sentence established the social context and the following target sentence ended with a critical word that informed the reader of the character's socio-emotional response to the situation. Critical words that mismatched rather than matched with a character's expected feelings elicited a larger ERP negativity (N400) ~200-500 ms after word onset, followed by a larger frontal positivity. Dipole source modeling results indicated that an anterior temporal lobe source accounted for the N400-like effect, which we attribute to the increased demands of integrating general knowledge about social situations (e.g. scripts) with personal- and context-specific information. An additional mediofrontal source contributed to the later ERP effect and presumably reflects high-level mindreading functions. Together, these findings indicate that readers rapidly infer and evaluate on-line a character's likely socio-emotional response based on the prototypical information provided by the text.
Disruption of intraflagellar protein transport in photoreceptor cilia causes Leber congenital amaurosis in humans and mice
2011-05-23

The mutations that cause Leber congenital amaurosis (LCA) lead to photoreceptor cell death at an early age, causing childhood blindness. To unravel the molecular basis of LCA, we analyzed how mutations in LCA5 affect the connectivity of the encoded protein lebercilin at the interactome level. In photoreceptors, lebercilin is uniquely localized at the cilium that bridges the inner and outer segments. Using a generally applicable affinity proteomics approach, we showed that lebercilin specifically interacted with the intraflagellar transport (IFT) machinery in HEK293T cells. This interaction disappeared when 2 human LCA-associated lebercilin mutations were introduced, implicating a specific disruption of IFT-dependent protein transport, an evolutionarily conserved basic mechanism found in all cilia. Lca5 inactivation in mice led to partial displacement of opsins and light-induced translocation of arrestin from photoreceptor outer segments. This was consistent with a defect in IFT at the connecting cilium, leading to failure of proper outer segment formation and subsequent photoreceptor degeneration. These data suggest that lebercilin functions as an integral element of selective protein transport through photoreceptor cilia and provide a molecular demonstration that disrupted IFT can lead to LCA.
Impaired tumor rejection by memory CD8 T cells in mice with NKG2D dysfunction
2011-05-23

Abstract Cytotoxic T cells are important effectors for robust antitumor immune responses. However, tumor‐infiltrating CD8 T cells are often functionally impaired. Insufficient antitumor activity of CD8 T cells can be due to a lack of costimulatory signals. NKG2D is such a costimulatory receptor on CD8 T cells that facilitates immunorecognition of stressed and malignant cells, promotes tumor rejection by NK and CD8 T cells and contributes to immunosurveillance of spontaneous malignancies. Previous reports suggested an involvement of NKG2D in establishing CD8 T cell‐mediated antitumor memory. However, the significance of NKG2D for the generation and effector phase of memory CD8 T cell responses is largely unknown. To address these issues, we made use of a transgenic mouse model (H2‐K b ‐MICA mice) where the human NKG2D ligand MICA is ubiquitously and constitutively expressed resulting in a severe dysfunction of NKG2D. Both, ovalbumin (OVA)‐specific (H2‐K b /OVA 257–264 ) memory CD8 T cells arisen from the endogenous T cell pool and adoptively transferred OVA‐specific OT‐I memory cells were unable to control growth of an OVA‐expressing lymphoma in H2‐K b ‐MICA mice. While expansion of memory T cells in these mice on antigen challenge was not different from controls, CD8 memory T cells of H2‐K b ‐MICA mice did not effectively eliminate tumor cells in vivo . Altogether, our data suggest that NKG2D has no major role in the generation and expansion of memory CD8 T cells, but rather substantially enhances the cytolytic effector responses of reactivated memory T cells and thereby contributes to an efficacious tumor rejection.
Correlation of Daptomycin Resistance in a Clinical Staphylococcus aureus Strain with Increased Cell Wall Teichoic Acid Production and d -Alanylation
2011-05-24

ABSTRACT Cell wall thickening is a common feature among daptomycin-resistant Staphylococcus aureus strains. However, the mechanism(s) leading to this phenotype is unknown. We examined a number of cell wall synthesis pathway parameters in an isogenic strain set of S. aureus bloodstream isolates obtained from a patient with recalcitrant endocarditis who failed daptomycin therapy, including the initial daptomycin-susceptible parental strain (strain 616) and two daptomycin-resistant strains (strains 701 and 703) isolated during daptomycin therapy. Transmission electron microscopy demonstrated significantly thicker cell walls in the daptomycin-resistant strains than in the daptomycin-susceptible strain, a finding which was compatible with significant differences in dry cell weight of strain 616 versus strains 701 to 703 ( P &lt; 0.05). Results of detailed analysis of cell wall muropeptide composition, the degree of peptide side chain cross-linkage, and the amount of the peptidoglycan precursor, UDP-MurNAc-pentapeptide, were similar in the daptomycin-susceptible and daptomycin-resistant isolates. In contrast, the daptomycin-resistant strains contained less O-acetylated peptidoglycan. Importantly, both daptomycin-resistant strains synthesized significantly more wall teichoic acid (WTA) than the parental strain ( P &lt; 0.001). Moreover, the proportion of d -alanylated WTA species was substantially higher in the daptomycin-resistant strains than in the daptomycin-susceptible parental strain ( P &lt; 0.05 in comparing strain 616 versus strain 701). The latter phenotypic findings correlated with (i) enhanced tagA and dltA gene expression, respectively, and (ii) an increase in surface positive charge observed in the daptomycin-resistant versus daptomycin-susceptible isolates. Collectively, these data suggest that increases in WTA synthesis and the degree of its d -alanylation may play a major role in the daptomycin-resistant phenotype in some S. aureus strains.
Laterally Resolved Orientation and Film Thickness of Polar Metal Chlorine Phthalocyanines on Au and ITO
2011-05-24

The molecular orientation and homogeneity of gallium(III) and aluminum(III) chlorine phthalocyanine (GaClPc and AlClPc) are studied on flat (gold single crystal, Au(100)) and rough surfaces (indium tin oxide, ITO) by Raman spectroscopy in combination with X-ray absorption spectroscopy (XAS) in detail. In the case of Raman spectroscopy, Euler angles are used to describe the geometry while Raman imaging provides insight into homogeneity. For XAS, synchrotron radiation is applied to study the angle dependence of the excitation structure. On Au(100) the molecules are highly ordered and tend to align parallel to the surface (lying) with a layer by layer growth mode. Contrarily, on technically relevant substrates, as in the case of ITO, less ordered films due to the roughness of the surface nature are present. The results are discussed in relation to the substrate's nature and the influence of dipole moments.
Adipocytokines and CD34+ Progenitor Cells in Alzheimer's Disease
2011-05-25

Our findings suggest that low plasma levels of leptin and increased numbers of CD34(+) progenitor cells are both associated with AD. In addition, the results of our study provide first evidence that increased leptin plasma levels are associated with a reduced number of CD34(+) progenitor cells in AD patients. These findings point towards a combined involvement of leptin and CD34(+) progenitor cells in the pathogenesis of AD. Thus, plasma levels of leptin and circulating CD34(+) progenitor cells could represent an important molecular link between atherosclerotic diseases and AD. Further studies should clarify the pathophysiological role of both adipocytokines and progenitor cells in AD and possible diagnostic and therapeutic applications.
Chlorine Isotope Analysis of Organic Contaminants Using GC–qMS: Method Optimization and Comparison of Different Evaluation Schemes
2011-05-25

Compound-specific online chlorine isotope analysis of chlorinated hydrocarbons was evaluated and validated using gas chromatography coupled to a regular quadrupole mass spectrometer (GC-qMS). This technique avoids tedious off-line sample pretreatments, but requires mathematical data analysis to derive chlorine isotope ratios from mass spectra. We compared existing evaluation schemes to calculate chlorine isotope ratios with those that we modified or newly proposed. We also tested systematically important experimental procedures such as external vs. internal referencing schemes, and instrumental settings including split ratio, ionization energy, and dwell times. To this end, headspace samples of tetrachloroethene (PCE), trichloroethene (TCE), and cis-dichloroethene (cDCE) at aqueous concentrations in the range of 20-500 μg/L (amount on-column range: 3.2-115 pmol) were analyzed using GC-qMS. The results (37Cl/35Cl ratios) showed satisfying to good precisions with relative standard deviations (n = 5) between 0.4‰ and 2.1‰. However, we found that the achievable precision considerably varies depending on the applied data evaluation scheme, the instrumental settings, and the analyte. A systematic evaluation of these factors allowed us to optimize the GC-qMS technique to determine chlorine isotope ratios of chlorinated organic contaminants.
40Ar/39Ar age of the Lonar crater and consequence for the geochronology of planetary impacts
2011-05-25

Abstract Asteroid impacts play an important role in the evolution of planetary surfaces. In the inner solar system, the large majority of impacts occur on bodies (e.g., asteroids, the Moon, Mars) covered by primitive igneous rocks. However, most of the impacts recorded on Earth occur on different rock types and are poor proxies for planetary impacts. The Lonar crater is a 1.88-km-diameter, Quaternary age crater (Fig. 1) located on the ca. 66 Ma Deccan basaltic traps in Maharashtra (India), and is one of the very few craters on Earth emplaced directly on basaltic lava flows. We carried out 12 40Ar/39Ar step-heating experiments on 4 melt rock samples in order to (1) obtain a precise age for the Lonar crater; (2) study the response of isotopic chronometers during impacts on mafic target rocks; and (3) better understand the dating of extraterrestrial impact craters. We obtained 10 plateau and 9 inverse isochron ages on various aliquots. Combination of selected data into a global inverse isochron yielded an age of 570 ± 47 ka (MSWD = 1.1; P = 0.24). In comparison, previous nonisotopic investigations on rocks thought to be affected by secondary processes yielded a range of much younger ages (ca. 12–62 ka). The measured 40Ar/36Ar trapped values offer a direct comparison with the atmospheric benchmark value and allow us to test the inherited 40Ar* degassing capacity of basaltic impact melt rocks. The 40Ar/36Ar ratio of 296.5 ± 1.7 is indistinguishable from the atmospheric composition and suggests that inherited 40Ar* is absent from the melt rock. This result substantiates diffusion models that predict a near-complete degassing of low-viscosity melt (e.g., basalts) during impact, and demonstrates for the first time that inherited 40Ar* is less problematic for 40Ar/39Ar dating of impact events in basaltic igneous rocks compared to Si-rich rocks. These results provide direct evidence that basaltic melt rocks are excellent candidates for recording the timing of planetary impact events and, as far as dating is concerned, should be the preferred targets of sample recovery by future missions.
Fostering the analytical competency of pre-service teachers in a computer-supported case-based learning environment: A matter of perspective?
2011-05-25

Abstract Analytical competency in classroom situations can be seen as a crucial aspect of teachers' professional competency. While case-based learning is considered to have great potential for teacher education, particularly with respect to the promotion of teachers' analytical skills, there have been very few attempts to investigate the effects of corresponding instructional support. The present empirical study investigated the effects of instructional support in the form of multiple perspectives (i.e. authentic comments made by teachers and learners) and the presentation format of these perspectives in a computer-supported case-based learning environment which was based on the principles of cognitive flexibility theory. Twenty-nine foreign-language student teachers participated in the study. Experimental groups were presented with multiple perspectives in a video (plus audio track) or audio-track format. A control group did not have access to these multiple perspectives. The instructional support with multiple perspectives positively influenced learning processes and outcomes with respect to a central dimension of analytical competency – learners' ability to apply conceptual knowledge to case information. Learners with access to multiple perspectives as "audio only" outperformed learners in the "audio + video" condition, who did not substantially differ from the control group. Keywords: media in educationmultimedia and hypermedia systemscase-based learningmultiple perspectivescognitive flexibilityteacher educationskills acquisition
Theoretical and Instructional Aspects of Learning with Visualizations
2011-05-25

Multimedia environments consist of verbal and visual representations that, if appropriately processed, allow for the construction of an integrated mental model of the content. Whereas much is known on how students learn from verbal representations, there are fewer insights regarding the processing of visual information, alone or in conjunction with text. This chapter uses a semiotics approach to provide a defi- nition of visualizations as a specific form of external representation, and then discusses the differences between verbal and visual representations in how they represent information. Finally, it discusses how meaning is achieved when learning with them. The next section discusses basic perceptual and cognitive processes relevant to learning with visualizations. This background is used to specify the instructional functions that visualizations have either as self-contained instructional messages or as text adjuncts. Moreover, the role of individual differences in processing visualizations is highlighted. The chapter ends with methodological suggestions concerning the important role of interdisciplinary research and assessment methods in this area.
A hairy business—Periostracal hair formation in two species of helicoid snails (Gastropoda, Stylommatophora, Helicoidea)
2011-05-25

Abstract In molluscs, the calcareous shell is covered externally by a thin organic layer, the periostracum. The periostracum of some pulmonate species is of special taxonomic interest because it bears distinct microscale architectures. Where and how these structures are formed is as yet unknown. Using histological sections through their shells, gelatin cuts, and live observations I studied the pattern by which the periostracal hair‐like projections in two helicoid land snail species are secreted and evenly arranged on the shell. The results indicate a complex mechanism: a hair is formed in the periostracal groove independently of the periostracum, after which it is attached to the edge of the shell, drawn out of the tissue, and finally swivelled to the upper side of the periostracum. Upon further growth of the periostracum, the hairs are finally fixed upright on the shell. J. Morphol. 2011. © 2011 Wiley‐Liss, Inc.
Thermal Imaging as a Noninvasive Diagnostic Tool for Anterior Knee Pain Following Implantation of Artificial Knee Joints
2011-05-25

Normal 0 21 false false false MicrosoftInternetExplorer4 The variety of radiographic diagnostic used to diagnose pain localised close to metal implants is still limited. Especially magnetic resonance results can not be analysed because of artefacts. In this article we present for the first time a direct correlation between an increase in skin temperature and existent anterior knee pain after total knee arthroplasty (TKA) measured with thermography. In a standardised way 26 knees were analysed. Thermographic photos were taken from frontal, medial and lateral directions with a computer-assisted infrared thermograph . In medial location (median 0.95 °C, p=0.0043), as well as in lateral location (median 0.5 °C, p=0.032) temperatures in locations with pain were significantly higher compared to the reference field. M edian temperature difference between pain localization and localizations without pain was 0.7 °C and ranged from 0.1 °C to 1.7 °C on the side of the pain. In the ROC analysis the sensitivity of this method was 1.0 and specificity was 0.917. The evidence of a significant increase in skin temperature on the painful sites opened up the possibility to localize and assess pain more precisely in patients with total knee prosthesis. We consider this novel, rapid, inexpensive and non-invasive technology to posses the potential to become a useful and objective tool for diagnosis of pain and inflammation and to generate digital data that can be stored and analysed in clinical practice.
In vitro responsiveness of human muscle cell peroxisome proliferator‐activated receptor δ reflects donors’ insulin sensitivity in vivo
2011-05-25

Eur J Clin Invest 2011; 41 (12): 1323–1329 Abstract Background Peroxisome proliferator‐activated receptor δ (PPARδ) activation enhances muscular fatty acid oxidation and oxidative phosphorylation, and muscle’s oxidative capacity positively associates with whole‐body insulin sensitivity. Therefore, we asked here whether human muscle cell PPARD expression is a determinant of donors’ insulin sensitivity. Materials and methods Skeletal muscle cells derived from 38 nondiabetic donors were differentiated in vitro to myotubes, and gene (mRNA) expression was quantified by real‐time RT–PCR. Donors’ insulin sensitivity was calculated from plasma insulin and glucose levels during oral glucose tolerance test (OGTT) and hyperinsulinemic‐euglycemic clamp. Results Basal myotube PPARD expression was closely related to the expression of its target genes PDK4 and ANGPTL4 ( P = 0·0312 and P = 0·0003, respectively). Basal PPARD , PDK4 and ANGPTL4 expression levels were not associated with donors’ insulin sensitivity ( P &gt; 0·2, all). Treatment of myotubes with a selective high‐affinity PPARδ agonist (GW501516) did not change mean PPARD , but enhanced mean PDK4 and ANGPTL4 expression 13‐ and 16‐fold, respectively ( P &lt; 0·0001, both). The individual PDK4 and ANGPTL4 expression levels reached upon GW501516 treatment were associated with donors’ insulin sensitivity neither ( P &gt; 0·2, both). However, GW501516‐mediated fold increments in PDK4 and ANGPTL4 expression, reflecting PPARδ responsiveness, were positively associated with donors’ insulin sensitivity derived from OGTT ( P = 0·0182 and P = 0·0231, respectively) and hyperinsulinemic‐euglycemic clamp ( P = 0·0046 and P = 0·0258, respectively). Conclusions Using a highly selective pharmacological tool, we show here that the individual responsiveness of human muscle cell PPARδ, rather than the absolute PPARD expression level, represents a major determinant of insulin sensitivity.
Patterns of Social Practice
2011-05-25

In this chapter, the application of patterns in the context of social practice will be considered from a psychological point of view. After briefly introducing the history of patterns, this chapter will discuss the specific conditions that apply for formulating and using patterns of social practice, as well as the benefits and challenges of their application. This discussion will result in four main challenges. In order to address them, the chapter presents psychological approaches that deal with the relevant issues and help to understand potential benefits of patterns of social practice. It concludes with some remaining open questions for future research. The entire chapter focuses on the structure that patterns provide, and how this structure supports the communication, exchange, and learning of social practice. The discussion of pattern writing processes (e.g., the process of shepherding) would need a motivational and practical consideration rather than a cognitive psychological one.
Software Process Model using Dynamic Bayesian Networks
2011-05-25

This chapter describes a methodology to support the management of large scale software projects in optimizing product correction effort versus initial development costs over time. The Software Process Model (SPM) represents the implementation of this approach on a level of detail explicitly developed to meet project manager’s demands. The underlying technique used in this approach is based on Dynamic Bayesian Networks (DBNs). The use of Bayesian Networks (BNs) enables the representation of causal relationships among process and product key performance indicators elicited either by data or expert knowledge. DBNs provide an insight into various aspects of SPM over time to assess current as well as predicting future model states. The objective of this chapter is to describe the practical approach to establish SPM as state of the art decision support in an industrial environment.
Sirolimus-eluting stents vs. bare-metal stents for treatment of focal lesions in infrapopliteal arteries: a double-blind, multi-centre, randomized clinical trial
2011-05-26

Mid-term patency rates of focal infrapopliteal lesions are substantially improved with sirolimus-eluting stent compared with bare-metal stent. Corresponding to the technical results, the changes in Rutherford-Becker classification reveal a significant advantage for the sirolimus-eluting stent.