julilili42/papers huggingface dataset:
Quantifying Thiol Ligand Density of Self-Assembled Monolayers on Gold Nanoparticles by Inductively Coupled Plasma–Mass Spectrometry
2013-01-21

Gold nanoparticles (GNPs) are often used as colloidal carriers in numerous applications owing to their low-cost and size-controlled preparation as well as their straightforward surface functionalization with thiol containing molecules forming self-assembling monolayers (SAM). The quantification of the ligand density of such modified GNPs is technically challenging, yet of utmost importance for quality control in many applications. In this contribution, a new method for the determination of the surface coverage of GNPs with thiol containing ligands is proposed. It makes use of the measurement of the gold-to-sulfur (Au/S) ratio by inductively coupled plasma mass spectrometry (ICP-MS) and its dependence on the nanoparticle diameter. The simultaneous ICP-MS measurement of gold and sulfur was carefully validated and found to be a robust method with a relative standard uncertainty of lower than 10%. A major advantage of this method is the independence from sample preparation; for example, sample loss during the washing steps is not affecting the results. To demonstrate the utility of the straightforward method, GNPs of different diameters were synthesized and derivatized on the surface with bifunctional (lipophilic) ω-mercapto-alkanoic acids and (hydrophilic) mercapto-poly(ethylene glycol) (PEG)(n)-carboxylic acids, respectively, by self-assembling monolayer (SAM) formation. Thereby, a size-independent but ligand-chain length-dependent ligand density was found. The surface coverage increases from 4.3 to 6.3 molecules nm−2 with a decrease of ligand chain length from 3.52 to 0.68 nm. Furthermore, no significant difference between the surface coverage of hydrophilic and lipophilic ligands with approximately the same ligand length was found, indicating that sterical hindrance is of more importance than, for example, intermolecular strand interactions of Van der Waals forces as claimed in other studies.
Superior colliculus inactivation alters the relationship between covert visual attention and microsaccades
2013-01-21

Abstract Microsaccades are tiny saccades that occur during gaze fixation. Whereas these movements have traditionally been viewed as random, it was recently discovered that microsaccade directions can be significantly biased by covertly attended visual stimuli. The detailed mechanisms mediating such a bias are neither known nor immediately obvious, especially because the amplitudes of the movements influenced by attentional cueing could be up to two orders of magnitude smaller than the eccentricity of the attended location. Here, we tested whether activity in the peripheral superior colliculus ( SC ) is necessary for this correlation between attentional cueing and microsaccades. We reversibly and focally inactivated SC neurons representing peripheral regions of visual space while rhesus monkeys performed a demanding covert visual attention task. The normal bias of microsaccade directions observed in each monkey before SC inactivation was eliminated when a cue was placed in the visual region affected by the inactivation; microsaccades were, instead, biased away from the affected visual space. When the cue was placed at another location unaffected by SC inactivation, the baseline cue‐induced bias of microsaccade directions remained mostly intact, because the cue was in unaffected visual space, and any remaining changes were again explained by a repulsion of microsaccades away from the inactivated region. Our results indicate that peripheral SC activity is required for the link between microsaccades and the cueing of covert visual attention, and that it could do so by altering the probability of triggering microsaccades without necessarily affecting the motor generation of these movements.
Bouncing behavior of microscopic dust aggregates
2013-01-21

\\n Context. Bouncing collisions of dust aggregates within the protoplanetary disk may have a significant impact on the growth process of planetesimals. Yet, the conditions that result in bouncing are not very well understood. Existing simulations studying the bouncing behavior used aggregates with an artificial, very regular internal structure.\\n Aims. Here, we study the bouncing behavior of sub-mm dust aggregates that are constructed applying different sample preparation methods. We analyze how the internal structure of the aggregate alters the collisional outcome and we determine the influence of aggregate size, porosity, collision velocity, and impact parameter.\\n Methods. We use molecular dynamics simulations where the individual aggregates are treated as spheres that are made up of several hundred thousand individual monomers. The simulations are run on graphic cards (GPUs).\\n Results. Statistical bulk properties and thus bouncing behavior of sub-mm dust aggregates depend heavily on the preparation method. In particular, there is no unique relation between the average volume filling factor and the coordination number of the aggregate. Realistic aggregates bounce only if their volume filling factor exceeds 0.5 and collision velocities are below 0.1 ms-1.\\n Conclusions. For dust particles in the protoplanetary nebula we suggest that the bouncing barrier may not be such a strong handicap in the growth phase of dust agglomerates, at least in the size range of ≈100 μm. \\n
Growth effects of nineteenth-century mass migrations: "Fome Zero" for Brazil?
2013-01-21

We estimate a long-run trend of Brazilian human capital that extends back to the very beginning of the eighteenth century. With new data on selective immigration during the era of mass migrations at the end of the nineteenth century, we show that human capital endowment of international migrants can induce effects on economic development that persist until today. According to our estimations, the effect of selective immigration on real GDP per capita in the year 2000 is significant and equals around US$75 overall. As a reference, this value equals the amount poor Brazilians get to supplement their subsistence in the 'Fome Zero' (Zero Hunger) program. We argue that human capital formation is a highly path-dependent and persistent process. Copyright , Oxford University Press.
Evolution of the concept of androgen-sensitive bladder cancer
2013-01-21

This reviews describes the concept of androgen-dependent growth of bladder cancer and the role of single-nucleotide polymorphisms (SNPs) located on chromosome 8q24 as a common carcinogenetic pathway for the development of concomitant prostate and bladder cancer. Recent genome-wide association studies have identified high-risk SNPs on chromosome 8q24 that have been linked with increased susceptibility for bladder and prostate cancer and alterations in the androgen receptor (AR) pathway. Muscle-invasive bladder cancers overexpress the AR, whereas in locally advanced or lymph-node positive stages loss of AR expression has been found. The prostate stem cell antigen (PSCA) gene possesses an androgen-responsive element (ARE) in its promoter region. Heterozymous and homozygous carriers of the SNP rs22940008 in the first exon of the PSCA gene are at increased risk for invasive bladder cancers. They exhibit significantly lower PSCA messenger RNA expression than patients with the wild-type genotype. Loss of the AR responsivity of the PSCA promoter may be a result of an altered affinity of the AR to the ARE mediated by the rs2294008 SNP or reduced expression of AR coactivators. Thereafter, induction of an androgen-independent mechanism, i.e. the insulin-like growth factor binding protein-2 signalling pathway--a key event in the development of hormone-independent prostate cancer--may increase tumour aggressiveness and metastatic potential of invasive bladder cancer cells. Loss of PSCA expression may represent an important step for androgen-independent growth, linked with the presence of the rs2294008 SNP. Determination of the AR status in cystectomy specimens offers new therapeutic approaches in locally advanced bladder cancer.
Security type error diagnosis for higher-order, polymorphic languages
2013-01-21

We combine the type error slicing and heuristics based approaches to type error diagnostic improvement within the context of type based security analysis on a let-polymorphic call by value lambda calculus extended with lists, pairs and the security specific constructs declassify and protect. We define and motivate four classes of heuristics that help diagnose inconsistencies among the constraints, and show their effect on a selection of security incorrect programs.
Search for Photon-Linelike Signatures from Dark Matter Annihilations with H.E.S.S.
2013-01-22

Gamma-ray line signatures can be expected in the very-high-energy (E(γ)>100 GeV) domain due to self-annihilation or decay of dark matter (DM) particles in space. Such a signal would be readily distinguishable from astrophysical γ-ray sources that in most cases produce continuous spectra that span over several orders of magnitude in energy. Using data collected with the H.E.S.S. γ-ray instrument, upper limits on linelike emission are obtained in the energy range between ∼ 500 GeV and ∼ 25 TeV for the central part of the Milky Way halo and for extragalactic observations, complementing recent limits obtained with the Fermi-LAT instrument at lower energies. No statistically significant signal could be found. For monochromatic γ-ray line emission, flux limits of (2 × 10(-7) -2 × 10(-5)) m(-2) s(-1) sr(-1) and (1 × 10(-8) -2 × 10(-6)) m(-2) s(-1)sr(-1) are obtained for the central part of the Milky Way halo and extragalactic observations, respectively. For a DM particle mass of 1 TeV, limits on the velocity-averaged DM annihilation cross section ⟨σv⟩(χχ → γγ) reach ∼ 10(-27) cm(3)s(-1), based on the Einasto parametrization of the Galactic DM halo density profile.
Exploring the association between genetic variation in the SUMO isopeptidase gene USPL1 and breast cancer through integration of data from the population‐based GENICA study and external genetic databases
2013-01-22

Small ubiquitin‐like modifier (SUMO) proteins are covalently attached to target proteins to modify their function. SUMO conjugation participates in processes tightly linked to tumorigenesis. Recently USPL1 (ubiquitin‐specific peptidase‐like (1) was identified as a SUMO isopeptidase. We report here on the first exploratory study investigating the relationship between genetic variability in USPL1 and breast cancer. Three potentially functional nonsynonymous coding SNPs (rs3742303, rs17609459, rs7984952) were genotyped in 1,021 breast cancer cases and 1,015 controls from the population‐based GENICA study. We took advantage of multiple genotype imputation based on HapMap and the 1000 Genomes Project data to refine the association screening in the investigated region. Public genetic databases were also used to investigate the relationship with USPL1 expression in lymphoblastoid cell lines and breast tissue. Women homozygous for the minor C allele of rs7984952 showed a lower risk of Grade 3 breast tumors compared to TT homozygotes (OR 0.50, 95% CI 0.30‐0.81). Case‐only analyses confirmed the association between rs7984952 and tumor grade (OR 0.60, 95% CI 0.39‐0.93). Imputation results in a 238 kb region around rs7984952 based on HapMap and the 1000 Genomes Project data were similar. No imputed variant showed an association signal stronger than rs7984952. USPL1 expression in tumor breast tissue increased with the number of C alleles. The present study illustrates the contribution of multiple imputation of genotypes using public data repositories to standard genotyping laboratory. The provided information may facilitate the design of independent studies to validate the association between USPL1 rs7984952 and risk of Grade 3 breast tumors.
Algebraic data types for language-integrated queries
2013-01-22

The seamless integration of relational databases and programming languages remains a major challenge. Mapping rich data types featured in general-purpose programming languages to the relational data model is one aspect of this challenge. We present a novel technique for mapping arbitrary (nonrecursive) algebraic data types to a relational data model, based on previous work on the relational representation of nested tables. Algebraic data types may be freely constructed and deconstructed in queries and may show up in the result type. The number of relational queries generated is small and statically determined by the type of the query. We have implemented the mapping in the Database Supported Haskell (DSH) library.
Mathematical models meet linguistic data and vice versa: an introduction to this special issue
2013-01-22

Linguistics in the 21st century is faced with a series of methodological innovations that have opened up new ways of describing language: experimental methods allow us to measure the activity of the human brain and to relate this activity to linguistic behavior and ability (Bornkessel-Schlesewsky and Schlesewsky 2009); new discoveries in genetics and in evolutionary biology show how certain genes play crucial roles in our language faculty and allow for a more precise definition of the moment when human language emerged (e.g.Benítez-Burraco et al. 2008); and the analysis of large amounts of data allow for the modeling of linguistic phenomena on a scale impossible to achieve in the past (e.g.Köhler 2012).Surprisingly, many of these innovations have emerged outside the discipline itself.Articles on linguistic issues are now being published in journals such as Nature, Science and Physica A by authors who work in the fields of statistical physics, evolutionary biology, cybernetics and mathematics.The reaction of "genuine" linguists, theoretical and empirical, is often rather skeptical and frequently leads to such studies being viewed with suspicion, or rejected altogether.And indeed, a general tendency in current "scientific" approaches to linguistics is to concentrate principally on the method and to impress with sophisticated experiments or quantitative analysis.However methodologically convincing, though, these studies sometimes belie shortcomings of both an empirical and a theoretical nature.This general observation also holds true for sociolinguistics and for the sociology of language, where a considerable number of recent studies have been published with exciting new proposals on the possibility of modeling individual behavior in a social context and on visualizations of phenomena such as language shift, language change and language death.Of course, as with any other scientific discipline, sociolinguistics has always dealt with models: models of societal stratification, models that link social constellations to linguistic attitudes and linguistic behavior, and even quantitative models that establish correlations
A Consideration of Biomarkers to be Used for Evaluation of Inflammation in Human Nutritional Studies
2013-01-23

To monitor inflammation in a meaningful way, the markers used must be valid: they must reflect the inflammatory process under study and they must be predictive of future health status. In 2009, the Nutrition and Immunity Task Force of the International Life Sciences Institute, European Branch, organized an expert group to attempt to identify robust and predictive markers, or patterns or clusters of markers, which can be used to assess inflammation in human nutrition studies in the general population. Inflammation is a normal process and there are a number of cells and mediators involved. These markers are involved in, or are produced as a result of, the inflammatory process irrespective of its trigger and its location and are common to all inflammatory situations. Currently, there is no consensus as to which markers of inflammation best represent low-grade inflammation or differentiate between acute and chronic inflammation or between the various phases of inflammatory responses. There are a number of modifying factors that affect the concentration of an inflammatory marker at a given time, including age, diet and body fatness, among others. Measuring the concentration of inflammatory markers in the bloodstream under basal conditions is probably less informative compared with data related to the concentration change in response to a challenge. A number of inflammatory challenges have been described. However, many of these challenges are poorly standardised. Patterns and clusters may be important as robust biomarkers of inflammation. Therefore, it is likely that a combination of multiple inflammatory markers and integrated readouts based upon kinetic analysis following defined challenges will be the most informative biomarker of inflammation.
Performance of the Elecsys Rubella IgG Assay in the Diagnostic Laboratory Setting for Assessment of Immune Status
2013-01-23

ABSTRACT Rubella in early pregnancy bears a high risk for congenital defects (e.g., cataracts, hearing loss, and heart disease) and for long-term sequelae in the newborn. Despite implementation of vaccination programs in many regions, the threat of devastating consequences from congenital rubella virus infection remains and careful screening of maternal immune status before and during pregnancy helps to reduce the risk. This study compared the performance of the Elecsys Rubella IgG assay with that of other assays routinely used for screening. Samples from 1,090 women undergoing routine antenatal care were tested using the Elecsys and Enzygnost Rubella IgG assays and the hemagglutination inhibition test. Samples with hemagglutination inhibition titers of &lt;32 ( n = 148) were additionally tested using the Vidas, AxSYM, Liaison, and Architect Rubella IgG assays. Agreement of qualitative results from the Elecsys, Enzygnost, and hemagglutination inhibition assays was good in all samples. All assays showed 100.0% specificity. In samples with hemagglutination inhibition titers of &lt;32, the Elecsys, AxSYM, and Enzygnost assays showed higher sensitivity (&gt;90.0%) than the other immunoassays (78.6 to 82.4%). The Elecsys assay reported significantly higher rubella virus IgG levels than the other immunoassays across the whole set of 1,090 samples, with the largest bias and deviation from limits of agreement in Bland-Altman analysis. In conclusion, the Elecsys assay is highly sensitive and specific with regard to qualitative results and suitable for routine automated screening. However, given the considerable variation between quantitative results from different immunoassays, testing methods should be documented and the same assay used throughout an individual's antenatal follow-up wherever possible.
Transfection of NSCLC cells with specific siRNA: A new cure?
2013-01-23

Aims: Survivin, E2F1 and serum response factor (SRF) are involved in the cell cycle regulation of different lung tumors. So far their potential use in the therapy of NSCLC is not proven. The purpose of this study was to evaluate the efficiency of siRNA transfection of NSCLC cell lines and to assess the effectiveness of siRNA to transiently influence cell division by specific gene silencing.
Extended experience with the double tunnel driveline technique in LVAD patients
2013-01-23

Objective: Driveline infections are still a major problem in patients treated with intrathoracic cardiac assist devices. We recently described a long subfascial, C shaped course of the driveline (double tunnel technique), which led to low infection rates and improved management of driveline problems 1.
How Sensitive Is the Human Visual System to the Local Statistics of Natural Images?
2013-01-24

A key hypothesis in sensory system neuroscience is that sensory representations are adapted to the statistical regularities in sensory signals and thereby incorporate knowledge about the outside world. Supporting this hypothesis, several probabilistic models of local natural image regularities have been proposed that reproduce neural response properties. Although many such physiological links have been made, these models have not been linked directly to visual sensitivity. Previous psychophysical studies of sensitivity to natural image regularities focus on global perception of large images, but much less is known about sensitivity to local natural image regularities. We present a new paradigm for controlled psychophysical studies of local natural image regularities and compare how well such models capture perceptually relevant image content. To produce stimuli with precise statistics, we start with a set of patches cut from natural images and alter their content to generate a matched set whose joint statistics are equally likely under a probabilistic natural image model. The task is forced choice to discriminate natural patches from model patches. The results show that human observers can learn to discriminate the higher-order regularities in natural images from those of model samples after very few exposures and that no current model is perfect for patches as small as 5 by 5 pixels or larger. Discrimination performance was accurately predicted by model likelihood, an information theoretic measure of model efficacy, indicating that the visual system possesses a surprisingly detailed knowledge of natural image higher-order correlations, much more so than current image models. We also perform three cue identification experiments to interpret how model features correspond to perceptually relevant image features.
Sensorimotor Recalibration Depends on Attribution of Sensory Prediction Errors to Internal Causes
2013-01-24

Sensorimotor learning critically depends on error signals. Learning usually tries to minimise these error signals to guarantee optimal performance. Errors can, however, have both internal causes, resulting from one's sensorimotor system, and external causes, resulting from external disturbances. Does learning take into account the perceived cause of error information? Here, we investigated the recalibration of internal predictions about the sensory consequences of one's actions. Since these predictions underlie the distinction of self- and externally produced sensory events, we assumed them to be recalibrated only by prediction errors attributed to internal causes. When subjects were confronted with experimentally induced visual prediction errors about their pointing movements in virtual reality, they recalibrated the predicted visual consequences of their movements. Recalibration was not proportional to the externally generated prediction error, but correlated with the error component which subjects attributed to internal causes. We also revealed adaptation in subjects' motor performance which reflected their recalibrated sensory predictions. Thus, causal attribution of error information is essential for sensorimotor learning.