julilili42/papers huggingface dataset:
Mentoring in higher education: does it enhance mentees’ research productivity?
2015-01-13

Mentoring programs are increasingly widespread in academia. Still, comparatively little is known about their effects. With the help of a self-collected dataset of 368 researchers in two different fields and accounting for self-selection via matching techniques, we find mentees in formal mentoring programs to be more productive than comparable researchers who do not participate in a formal program -- irrespective of whether these instead have an informal mentor or not. Informal mentoring relationships, to the contrary, do not positively affect mentees’ research productivity.
Segmentation-Based Attenuation Correction in Positron Emission Tomography/Magnetic Resonance
2015-01-13

Attenuation map artifacts that occur in a considerable percentage of PET/MR data sets have the potential to falsify PET quantification and visual PET interpretation. Nevertheless, on the basis of the present data, in the clinical interpretation setup, no changes in diagnosis due to μ-map artifacts may occur, especially when the μ-maps are checked for artifacts and PET/MR is read in synopsis with the NAC PET, if artifacts are present.
Considering digits in a current model of numerical development
2015-01-13

Numerical cognition has long been considered the perfect example of abstract information processing. Nevertheless, there is accumulating evidence in recent years suggesting that the representation of number magnitude may not be entirely abstract but may present a specific case of embodied cognition rooted in the sensory and bodily experiences of early finger counting and calculating. However, so far none of the existing models of numerical development considers the influence of finger-based representations. Therefore, we make first suggestions on (i) how finger-based representations may be integrated into a current model of numerical development; and (ii) how they might corroborate the acquisition of basic numerical competencies at different development levels.
Comparison of volume perfusion computed tomography and contrast-enhanced ultrasound for assessment of therapeutic effect of transarterial chemoembolization in patients with hepatocellular carcinoma: a preliminary report
2015-01-13

Background Evaluation of transarterial chemoembolization (TACE) by using contrast-enhanced ultrasound (CEUS) and volume perfusion computed tomography (VPCT) as methods that display tumor vascularization. Purpose To assess early results of TACE in patients with hepatocellular carcinoma (HCC) using CEUS and VPCT. Material and Methods Twenty patients with HCC underwent CEUS and VPCT in the pre- and post-TACE setting (1 day). Hepatic perfusion index (HPI), arterial liver perfusion (ALP), blood flow (BF), and blood volume (BV) were measured with VPCT. Peak intensity (PI), time-to-peak (TTP), and regional blood flow (RBF) were measured with CEUS. Sensitivity, specificity, negative and positive predictive values, and cutoff values for these parameters were calculated. Immediate tumor response after TACE was classified as responder or non-responder. Results were compared with those at follow-up after 2 and 4 months (FU 2mo /FU 4mo ) following modified RECIST. Results CEUS and VPCT showed comparable immediate post-TACE results in 20/20 cases. Complete response was confirmed in 10/20 patients at FU 2mo and in 9/20 at FU 4mo . For responders, reduction in HPI, ALP, BV, and BF at day 1 post TACE proved significant ( P &lt; 0.001). For non-responders, the course of all VPCT parameters proved non-significant. A cutoff of 40% reduction in HPI and a reduction in ALP of &gt;29.6%, in BV of &gt;41.4%, or in BF of &gt;53.1% was indicative of response according to FU 2mo . For responders only, changes in PI ( P &lt; 0.001), TTP ( P &lt; 0.01), and BF ( P &lt; 0.01) proved significant whereas for non-responders, all CEUS parameters proved non-significant. Conclusion CEUS performs equally to VPCT for assessment of early response to TACE in HCC by a lesion-by-lesion assessment and showed prognostic value at mid-term.
A multi-disciplinarily designed mesocosm to address the complex flow-sediment-ecology tripartite relationship on the microscale
2015-01-13

Abstract Background The stabilization of fine sediments via biofilms (‘biostabilization’) has various economic and ecological implications but is presently unaddressed within lotic waters. To investigate natural biofilm growth and functionality in freshwater sediments under controlled boundary conditions, a unique mesocosm was constructed that combines established know-how from engineering and natural sciences and consists of six straight flumes. To test the comparability of biofilm growth within one flume and between the flumes, extracellular polymeric substances (EPSs), microbial biomass and microbial community composition were closely monitored over time and space as well as in relation to biofilm adhesiveness (proxy for biostabilization). Results Most importantly, biofilm development and biostabilization capacity revealed no significant differences within flume regions or between the flumes and the biofilms significantly stabilized the substratum as compared to abiotic controls. However, interesting temporal successions in biofilm growth phases became visible in shifting abundance and diversity of bacteria and microalgae resulting in varying EPS secretion and biostabilization. Conclusions These findings demonstrated the importance of biostabilization for fine sediment dynamics in freshwaters. Secondly, this unique setup allows comparable biofilm growth under controlled environmental conditions, an important requisite for future research on the ecological significance and impact of biostabilization for ecosystem functioning at varying environmental scenarios.
2,3-Dihydro-4,5-diisopropyl-1,3-dimethylimidazol-2-yliden und seine Chalkogenone
2015-01-13

Abstract 2,3-Dihydro-4,5-diisopropyl-1,3-dimethylimidazol-2-ylidene ( 6 ) is prepared by reduction of the corresponding thion 7a with potassium. The selenium compound 7b is obtained from 6 and selenium. In the solid state, 7a and 7b exist as their isomers, as revealed by their crystal structures.
Spatial statistics and attentional dynamics in scene viewing
2015-01-14

In humans and in foveated animals visual acuity is highly concentrated at the center of gaze, so that choosing where to look next is an important example of online, rapid decision-making. Computational neuroscientists have developed biologically-inspired models of visual attention, termed saliency maps, which successfully predict where people fixate on average. Using point process theory for spatial statistics, we show that scanpaths contain, however, important statistical structure, such as spatial clustering on top of distributions of gaze positions. Here, we develop a dynamical model of saccadic selection that accurately predicts the distribution of gaze positions as well as spatial clustering along individual scanpaths. Our model relies on activation dynamics via spatially-limited (foveated) access to saliency information, and, second, a leaky memory process controlling the re-inspection of target regions. This theoretical framework models a form of context-dependent decision-making, linking neural dynamics of attention to behavioral gaze data.
An Intracellular Nanotrap Redirects Proteins and Organelles in Live Bacteria
2015-01-14

ABSTRACT Owing to their small size and enhanced stability, nanobodies derived from camelids have previously been used for the construction of intracellular “nanotraps,” which enable redirection and manipulation of green fluorescent protein (GFP)-tagged targets within living plant and animal cells. By taking advantage of intracellular compartmentalization in the magnetic bacterium Magnetospirillum gryphiswaldense , we demonstrate that proteins and even entire organelles can be retargeted also within prokaryotic cells by versatile nanotrap technology. Expression of multivalent GFP-binding nanobodies on magnetosomes ectopically recruited the chemotaxis protein CheW 1 -GFP from polar chemoreceptor clusters to the midcell, resulting in a gradual knockdown of aerotaxis. Conversely, entire magnetosome chains could be redirected from the midcell and tethered to one of the cell poles. Similar approaches could potentially be used for building synthetic cellular structures and targeted protein knockdowns in other bacteria. IMPORTANCE Intrabodies are commonly used in eukaryotic systems for intracellular analysis and manipulation of proteins within distinct subcellular compartments. In particular, so-called nanobodies have great potential for synthetic biology approaches because they can be expressed easily in heterologous hosts and actively interact with intracellular targets, for instance, by the construction of intracellular “nanotraps” in living animal and plant cells. Although prokaryotic cells also exhibit a considerable degree of intracellular organization, there are few tools available equivalent to the well-established methods used in eukaryotes. Here, we demonstrate the ectopic retargeting and depletion of polar membrane proteins and entire organelles to distinct compartments in a magnetotactic bacterium, resulting in a gradual knockdown of magneto-aerotaxis. This intracellular nanotrap approach has the potential to be applied in other bacteria for building synthetic cellular structures, manipulating protein function, and creating gradual targeted knockdowns. Our findings provide a proof of principle for the universal use of fluorescently tagged proteins as targets for nanotraps to fulfill these tasks.
A Fourier transform Raman spectrometer with visible laser excitation
2015-01-14

We present the development and performance of a Fourier transformation (FT)‐based Raman spectrometer working with visible laser (532 nm) excitation. It is generally thought that FT‐Raman spectrometers are not viable in the visible range where shot noise limits the detector performance and therein they are outperformed by grating based, dispersive ones. We show that contrary to this common belief, the recent advances of high‐performance interference filters makes the FT‐Raman design a valid alternative to dispersive Raman spectrometers for samples which do not luminesce. We critically compare the performance of our spectrometer to two dispersive ones: a home‐built single channel and a state‐of‐the‐art charge coupled device‐based instruments. We demonstrate a similar or even better sensitivity than the charge coupled device‐based dispersive spectrometer particularly when the laser power density is considered. The instrument possesses all the known advantages of the FT principle of spectral accuracy, high throughput, and economic design. We also discuss the general considerations, which helps the community reassess the utility of the different Raman spectrometer designs. Copyright © 2015 John Wiley &amp; Sons, Ltd.
The Pyrazolobenzothiazine Core as a New Chemotype of p38 Alpha Mitogen‐Activated Protein Kinase Inhibitors
2015-01-14

The identification, synthesis, biological activity, and binding mode prediction of a series of pyrazolobenzothiazines as novel p38 α MAPK inhibitors are reported. Some of these compounds showed interesting activity in both p38 α MAPK and TNF ‐ α release assays. Derivative 6 emerged as the most interesting compound with IC 50 (p38 α ) = 0.457 μ m , IC 50 ( TNF ‐ α ) = 0.5 μ m and a promising kinase selectivity profile. The obtained results strongly indicate the pyrazolobenzothiazine core as a new p38 α inhibitor chemotype worthy of future chemical optimization efforts directed toward identifying a new generation of anti‐inflammatory agents.
Toward NNLL threshold resummation for hadron pair production in hadronic collisions
2015-01-14

We investigate QCD threshold resummation effects beyond the next-to-leading logarithmic (NLL) order for the process H1H2 → h1h2X at high invariant mass of the produced hadron pair. We take into account the color structure of the underlying partonic hard-scattering cross sections and determine the relevant hard and soft matrices in color space that contribute to the resummed cross section at next-to-next-to-leading logarithmic (NNLL) accuracy. We present numerical results for fixed-target and collider regimes. We find a significant improvement compared to previous results at NLL accuracy. In particular, the scale dependence of the resummed cross section is greatly reduced. Use of the most recent set of fragmentation functions also helps in improving the comparison with the experimental data. Our calculation provides a step towards a systematic NNLL extension of threshold resummation also for other hadronic processes, in particular for jet production. ar X iv
FlashCam: a novel Cherenkov telescope camera with continuous signal digitization
2015-01-14

The Cherenkov Telescope Array (CTA) will be the next generation ground-based observatory for cosmic gamma rays. The FlashCam camera for its mid-size telescope introduces a new concept, with a modest sampling rate of 250 MS/s, that enables a continuous digitization as well as event buffering and trigger processing using the same front-end FPGAs. The high performance Ethernet-based readout provides a dead-time free operation for event rates up to 30 kHz corresponding to a data rate of 2.0 GByte/s sent to the camera server. We present the camera design and the current status of the project.
An X-ray Study for Origin of Galactic Cosmic Rays: Discovery of an X-ray Counterpart of HESS J1427–608
2015-01-14

T. Fujinaga1,2, K. Mori3, A. Bamba4 S. Kimura3, T. Dotani2,1,5, M. Ozaki2, K. Matsuta5,2, G. Puhlhofer6, H. Uchiyama7, J. S. Hiraga7, H. Matsumoto8 and Y. Terada9 1 Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8550, Japan 2 Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, 3-1-1 Yoshinodai, Chuo-ku, Sagamihara, Kanagawa 252-5210, Japan 3 University of Miyazaki, 1-1 Gakuen Kibanadai-Nishi, Miyazaki, 889-2192, Japan 4 Aoyama Gakuin University, 5-10-1 Fuchinobe, Chuo-ku, Sagamihara, Kanagawa 252-5258, Japan 5 Department of Space and Astronautical Science, The Graduate University for Advanced Studies, 3-1-1 Yoshinodai, Chuo-ku, Sagamihara, Kanagawa 252-5210, Japan 6 Institut fur Astronomie und Astrophysik, Universitat Tubingen, Sand 1, D 72076 Tubingen, Germany 7 The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan 8 Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8602, Japan 9 Saitama University, Shimo-Okubo 255, Sakura-ku, Saitama 338-8570, Japan
The LOFT perspective on neutron star thermonuclear bursts: White paper in support of the mission concept of the large observatory for X-ray timing
2015-01-14

The Large Area Detector (LAD) on the Large Observatory For X-ray Timing ( LOFT ), with a 8.5 m 2 photon- collecting area in the 2–30 keV bandpass at CCD-class spectral resolving power (λ/Δλ = 10 – 100), is designed for optimum performance on bright X-ray sources. Thus, it is well-suited to study thermonuclear X-ray bursts from Galactic neutron stars. These bursts will typically yield 2 x 10&lt;sup&gt;5&lt;/sup&gt; photon detections per second in the LAD, which is at least 15 times more than with any other instrument past, current or anticipated. The Wide Field Monitor (WFM) foreseen for LOFT uniquely combines 2–50 keV imaging with large (30%) prompt sky coverage. This will enable the detection of tens of thousands of thermonuclear X-ray bursts during a 3-yr mission, including tens of superbursts. Both numbers are similar or more than the current database gathered in 50 years of X-ray astronomy.
Combined PET/MR: A Technology Becomes Mature
2015-01-15

The combination of PET and MR imaging forms a powerful new imaging modality, PET/MR. The major advantages of concurrent PET/MR acquisitions range from patient comfort and increased throughput to multiparametric imaging and are evaluated and reviewed in this paper specifically with respect to their applications in research and diagnostics. Alongside the use of PET/MR in the field of preclinical research, this paper illuminates the impact of this new modality in the clinical field in such areas as neurology, oncology, and cardiology. Now that PET/MR technology has matured, attention is needed on standardizing education for nuclear and radiologic technologists and physicians specifically for this combined modality. Furthermore, the impact of this combined modality on health economy needs to be addressed in more detail to further propel its use.
Movement related slow cortical potentials in severely paralyzed chronic stroke patients
2015-01-15

Movement-related slow cortical potentials (SCPs) are proposed as reliable and immediate indicators of cortical reorganization in motor learning. SCP amplitude and latency have been reported as markers for the brain's computational effort, attention and movement planning. SCPs have been used as an EEG signature of motor control and as a main feature in Brain-Machine-Interfaces (BMIs). Some reports suggest SCPs are modified following stroke. In this study, we investigated movement-related SCPs in severe chronic stroke patients with no residual paretic hand movements preceding and during paretic (when they try to move) and healthy hand movements. The aim was to identify SCP signatures related to cortex integrity and complete paralysis due to stroke in the chronic stage. Twenty severely impaired (no residual finger extension) chronic stoke patients, of whom ten presented subcortical and ten cortical and subcortical lesions, underwent EEG and EMG recordings during a cue triggered hand movement (open/close) paradigm. SCP onset appeared and peaked significantly earlier during paretic hand movements than during healthy hand movements. Amplitudes were significantly larger over the midline (Cz, Fz) for paretic hand movements while contralateral (C4, F4) and midline (Cz, Fz) amplitudes were significantly larger than ipsilateral activity for healthy hand movements. Dividing the participants into subcortical only and mixed lesioned patient groups, no significant differences observed in SCP amplitude and latency between groups. This suggests lesions in the thalamocortical loop as the main factor in SCP changes after stroke. Furthermore, we demonstrated how, after long-term complete paralysis, post-stroke intention to move a paralyzed hand resulted in longer and larger SCPs originating in the frontal areas. These results suggest SCP are a valuable feature that should be incorporated in the design of new neurofeedback strategies for motor neurorehabilitation.
Concise Review: Modeling Multiple Sclerosis With Stem Cell Biological Platforms: Toward Functional Validation of Cellular and Molecular Phenotypes in Inflammation-Induced Neurodegeneration
2015-01-15

Abstract In recent years, tremendous progress has been made in identifying novel mechanisms and new medications that regulate immune cell function in multiple sclerosis (MS). However, a significant unmet need is the identification of the mechanisms underlying neurodegeneration, because patients continue to manifest brain atrophy and disability despite current therapies. Neural and mesenchymal stem cells have received considerable attention as therapeutic candidates to ameliorate the disease in preclinical and phase I clinical trials. More recently, progress in somatic cell reprogramming and induced pluripotent stem cell technology has allowed the generation of human “diseased” neurons in a patient-specific setting and has provided a unique biological tool that can be used to understand the cellular and molecular mechanisms of neurodegeneration. In the present review, we discuss the application and challenges of these technologies, including the generation of neurons, oligodendrocytes, and oligodendrocyte progenitor cells (OPCs) from patients and novel stem cell and OPC cellular arrays, in the discovery of new mechanistic insights and the future development of MS reparative therapies.
Correlated starting points for the functional renormalization group
2015-01-16

We present a general frame to extend functional renormalization group (fRG) based computational schemes by using an exactly solvable interacting reference problem as starting point for the RG flow. The systematic expansion around this solution accounts for a nonperturbative inclusion of correlations. Introducing auxiliary fermionic fields by means of a Hubbard-Stratonovich transformation, we derive the flow equations for the auxiliary fields and determine the relation to the conventional weak-coupling truncation of the hierarchy of flow equations. As a specific example we consider the dynamical mean field theory (DMFT) solution as reference system, and discuss the relation to the recently introduced DMF2RG and the dual-fermion formalism. © 2015 American Physical Society.
MRI-Based Radiation-Free Method for Navigated Percutaneous Radiofrequency Trigeminal Rhizotomy
2015-01-16

We present a simple radiation-free method for neuronavigation-assisted percutaneous RTR. This method proved to be safe and effective, and it is especially recommended for young, inexperienced neurosurgeons.
Inducing active demethylation through 5-Azacytidine open a new aspect for treatment of Hepatocellular Carcinoma
2015-01-16

Hepatocellular carcinoma (HCC) is the fifth deadliest cancer worldwide. Global deregulation of the methylation status is one of the main causes of HCC. The oxidation of 5-methylcytosine (5mC) triggers the formation of 5-hydroxymethylcytosine (5hmC). 5hmC can be depleted from the genome through down-regulation of the TET proteins leading to the demethylation of previously silenced genes. It has been reported that the anti-cancer drug 5-Azacytidine (5-Aza) mediates the activation of tumor suppressor genes through passive demethylation by inhibiting DNMT1. Our aim was to ascertain, if 5-Aza also induces an active demethylation by increasing the expression of 5hmC mediated by the proteins TET2 and TET3, which may lead to new approaches in cancer therapy.
Serum Reponse Factor (SRF) is a transcriptional activator of Mouse Double Minute 4 (MDM4) in hepatocellular carcinoma
2015-01-16

The Mouse Double Minute 4 (MDM4) represents a p53-binding protein acting as a transcriptional repressor. We have previously demonstrated that both MDM4 mRNA and protein levels are upregulated in about 50% of human hepatocellular carcinomas (HCC). Although we identified 1q32 gains as a mechanism leading to MDM4 overexpression in human HCC, many liver tumors show a balanced MDM4 gene locus, but high MDM4 mRNA levels. Thus, we hypothesized that dysregulated transcription may account for the high MDM4 expression observed in human liver tumors. Here, we show that overexpression of the Serum Reponse Factor (SRF) is involved in the transcriptional upregulation of MDM4 in HCC, thereby supporting its protumorigenic function.
Increased serum levels of regenerative miRNAs in patients with spontaneous recovery from acute liver failure
2015-01-16

Introduction: Acute liver failure (ALF) represents a life-threatening situation characterized by sudden and massive liver cell death in the absence of preexisting liver disease. Although most patients require liver transplantation to prevent mortality, some recover spontaneously and show complete liver regeneration. The molecular mechanisms of spontaneous recovery from ALF and the role of miRNAs are largely unknown. We therefore investigated miRNAs such as miR-21 and miR-221, which have been implicated to play a role in liver regeneration, in sera of ALF patients with or without spontaneous recovery. In addition, we analyzed growth-inhibitory target genes of those miRNAs as well as hepatocyte proliferation in liver tissues of spontaneously recovered and non-recovered ALF patients.