nils-herrmann/clean_scirepeval huggingface dataset:
Friction and Wear of Epoxy Composites Containing Silica Nanoparticles Grafted by Hyperbranched Aromatic Polyamide

Nano-sized SiO2 particles grafted with hyperbranched aromatic polyamide were employed as fillers for fabricating epoxy based composites. The hyperbranched aromatic polyamide was selected because its terminal amine groups could take part in the curing reaction of epoxy resin and covalently connect silica nanoparticles with the matrix. The experimental results proved the occurrence of this reaction, and indicated that the presence of the grafted SiO2 in epoxy does not change the overall curing mechanism of epoxy. In comparison to the composites filled with untreated nano-SiO2 particles, the composites with the grafted nano-SiO2 exhibited significantly improved sliding wear resistance and reduced frictional coefficient owing to the strong filler/matrix interfacial bonding. Moreover, hyperbranched aromatic polyamide grafted nano-SiO2 was more effective to enhance tribological properties of epoxy than linear polymers grafted versions.

Field of study: Materials science
Crystallization and preliminary X-ray diffraction analysis of a functional form of pneumolysin, a virulence factor from Streptococcus pneumoniae.

Pneumolysin is a virulence factor from Streptococcus pneumoniae, a Gram-positive bacterial pathogen which causes human infections with a severe impact on mortality and morbidity worldwide. The enzyme belongs to a group of cholesterol-dependent cytolysins and interacts with its cholesterol receptor on target cells, leading to pneumolysin insertion into target-cell membranes and subsequently to pore formation and cell lysis. Pneumolysin has been overexpressed, purified and crystallized for X-ray diffraction studies. Crystals have been obtained in the presence of cholesterol in an effort to produce a three-dimensional structure of pneumolysin in its fully functional form with the enzyme bound to its activator. This is the first report of the crystallization of a cholesterol-dependent cytolysin in the presence of bound cholesterol. The vapor-diffusion method using ammonium sulfate as a precipitation agent was used to grow crystals in the presence of n-octyl-beta-D-glucopyranoside and phosphatidylcholine. Crystals of this 53 kDa molecule complexed with cholesterol diffracted X-rays to 3.3 A. The crystal unit cell has parameters a = b = 191.45, c = 66.16 A, alpha = beta = 90.0, gamma = 120 degrees and belongs to the trigonal space group P3. The determination of the three-dimensional structure of this pneumococcal cytolysin is in progress.

Field of study: Chemistry
Microbial communities in wetlands of the Athabasca oil sands: genetic and metabolic characterization.

Naphthenic acids are a complex family of naturally occurring cyclic and acyclic carboxylic acids that are present in the acidic fraction of petroleum. Naphthenic acids are acutely toxic to aquatic organisms. Previous studies showed that wetland sediments exposed to oil sands process water containing naphthenic acids had higher rates of naphthenic acid degradation in vitro compared with unexposed wetlands. In this study we compare the microbial community structures in sediments from wetlands exposed to different amounts of oil sands process water using BIOLOG, phospholipid fatty acid analysis and denaturing gradient gel electrophoresis of total bacterial DNA. Community profiles were compared using cluster analysis. BIOLOG profiles were primarily influenced by seasonal trends rather than naphthenic acids content. In contrast, phospholipid fatty acid analysis comparisons clustered communities that had higher levels of residual oil, although this association was not strong. In contrast, cluster diagrams produced from the denaturing gradient gel electrophoresis data clearly separated bacterial communities according to naphthenic acids concentrations, indicating that naphthenic acids content was a major influence on the composition of the bacterial community. In addition, denaturing gradient gel electrophoresis profiles indicated that naphthenic acids-exposed bacterial communities were homogeneous on a scale of meters, whereas unexposed (off-site) wetlands were less homogeneous.

Field of study: Biology, Environmental science
Effects of 2-[3-estrone-N-ethyl-piperazine-methyl]tetracycline (XW630) on osteoporosis in ovariectomized rats.

To study the effects of 2-[3-estrone-N-ethyl-piperazine-methyl]tetracycline (XW630) on experimental osteoporosis in ovariectomized (OVX) rats.



Serum estradiol (E2) content and bone 1-carboxyglutamic acid-containing protein (BGP) content were measured by radioimmunoassay. With undecalcified bone section and tetracycline intraperitoneal labeling, the bone static and dynamic data were studied in right femur samples.



After treatment with XW630 2.5 mg.kg-1, serum BGP content increased by 75.7% but there was no change in serum E2 content and uterus weight compared with OVX rats. Compared with OVX rats, the static data of trabecular bone volume/total tissue volume, trabecular bone volume/sponge bone volume, and mean trabecular plate density were enhanced after treatment with XW630 for 13 wk. The dynamic data of single-labeled surface, double-labeled surface, trabecular osteoid surface, and bone formation rate in tissue level in XW630 group were increased and osteoid maturation period was shortened.



XW630 enhanced bone activation frequency and increased trabecular connectivity, stability, and strength. XW630 stimulated bone formation and inhibited bone resorption with no effect on reproductive system.

Field of study: Biology, Chemistry, Medicine
New Developments in Radiation Detectors and Electron Multipliers

This paper describes several electron devices for the detection of radiation. Discussed are a photomultiplier for UV and X-ray spectrum analysis which uses a switchable segmented photocathode; a large area scintillation counter tube which uses a large size multiplier structure giving it high coupling factor and high current capability; and a small, two terminal electron multiplier structure which uses an inclined strip of semiconductor material in an electric field. Illustrations and some performance data are given.

Field of study: Physics
Numerical Study of Nonperturbative Corrections to the Chiral Separation Effect in Quenched Finite-Density QCD.

We demonstrate the nonrenormalization of the chiral separation effect (CSE) in quenched finite-density QCD in both confinement and deconfinement phases using a recently developed numerical method which allows us, for the first time, to address the transport properties of exactly chiral, dense lattice fermions. This finding suggests that CSE can be used to fix renormalization constants for axial current density. Explaining the suppression of the CSE which we observe for topologically nontrivial gauge field configurations on small lattices, we also argue that CSE vanishes for self-dual non-Abelian fields inside instanton cores.

Field of study: Physics
Identity-based strong designated verifier signature revisited

Designated verifier signature (DVS) allows the signer to persuade a verifier the validity of a statement but prevent the verifier from transferring the conviction. Strong designated verifier signature (SDVS) is a variant of DVS, which only allows the verifier to privately check the validity of the signer's signature. In this work we observe that the unforgeability model considered in the existing identity-based SDVS schemes is not strong enough to capture practical attacks, and propose to consider another model which is shown to be strictly stronger than the old one. We then propose a new efficient construction of identity-based SDVS scheme, which is provably unforgeable under the newly proposed definition, based on the hardness of Computational Diffie-Hellman problem in the random oracle model. Our scheme is perfectly non-transferable in the sense that the signer and the designated verifier can produce identically distributed signatures on the same message. Besides, it is the first IBSDVS scheme that is non-delegatable with respect to (an identity-based variant of) the definition proposed by Lipmaa et al. (ICALP 2005).

Field of study: Computer science, Engineering
Tectonic evolution of the upper allochthon of the Órdenes complex (northwestern Iberian Massif): Structural constraints to a polyorogenic peri-Gondwanan terrane

The upper allochthon of northwest Iberia represents the most exotic terrane of this part of the European Variscan belt. Recent advances in the metamorphic petrology, structural geology, and geochronology of the upper allochthon in the Ordenes complex are integrated into a synthesis of its tectonic evolution, constraining the main tectonothermal events. Important aspects of this synthesis are (1) the interpretation of Cambro-Ordovician magmatism and earliest metamorphic event, as the result of drifting of a peri-Gondwanan terrane; (2) the subsequent shortening and crustal thickening of the terrane related to its subduction and accretion to Laurussia; (3) a younger cycle of shortening and extension resulting from convergence between Lau- russia and Gondwana; and (4) the emplacement of this exotic terrane as the upper allochthon, together with underlying ophiolitic and basal allochthons, during the Laurussia-Gondwana collision. Implications derived from the well-established tectonothermal sequence are discussed in the context of Paleozoic paleogeography and geodynamics. The evolution of this part of the belt is related first to the closure of the Tornquist Ocean, and later to that of the eastern branch of the Rheic Ocean. Furthermore, the relative paleopo- sitions of the upper allochthon and the Iberian autochthon in northern Gondwana are discussed.

Field of study: Geology
Knowledge hierarchies in the labor market

Many workers produce intangible, knowledge-intensive inputs, rather than participating directly in the production process. We develop a model where the labor market organizes itself in a knowledge hierarchy. Skills are segmented into successive clusters. Each cluster buys knowledge from the next one and sells knowledge as a production input to the preceding one. The model is useful to study the impact of improvements in the technology of knowledge transmission on inequality. It is shown that inequality goes up at the top of the income distribution, but not at the bottom.

Field of study: Economics
Leisure studies and intersectionality

The challenge of understanding and researching the intersections of complex multiple inequalities has been a key focus for a range of social science disciplines over the past two decades. This paper considers the potential use of intersectionality for engaging more critically with the multiple interconnections of power, identity and discrimination. It outlines some key tenets of intersectionality: as a theoretical perspective; as a methodological approach and as a somewhat elusive and often more loosely termed ‘framework’. It proposes some possible contributions that intersectionality can make to leisure scholarship, and, importantly, offers an assessment of leisure’s potential to contribute to wider debates on intersectionality. We argue that thinking intersectionally is a useful means of analysing leisure as a dynamic interplay of individual expression and the social relations within which leisure occurs. This is demonstrated through reference to two examples where ‘thinking intersectionally’ can inform analyses of leisure, one on public leisure space and the second on leisure and embodiment.

Field of study: Sociology
On the subject of typology: How Irish coastal communities' subjectivities reveal intrinsic values towards coastal environments

Ireland is working to double the economic contribution of its €2.2bn marine sector by 2030 by focusing on expanding offshore energy, shipping, commercial fishing, and tourism sectors. This growth will be sensitive to environmental considerations, with a stated goal of achieving healthy ecosystems ‘that provide monetary and non-monetary goods and services’. Such a goal may prove challenging if short-term economic priorities threaten long-term ecosystem functions and resilience. This study determines the intrinsic value of the marine realm via attitudinal data of stakeholders by employing a grounded theory approach utilizing Q-methodology. Stakeholders were sorted into three categorical factors (, each representing a significantly distinct ecological thought. It is evident within the scope of this study that stakeholders value and understand intrinsic value, despite it not being adequately represented in policy decisions to date. This research seeks to demonstrate how stakeholder engagement and Q-methodology can be utilized to address current policy shortcomings in the EU and Irish context, specifically when attempting to modernize policy approaches to be holistic and integrated.

Field of study: Environmental science
Laboratories of Statehood: Legal Intervention in Colonial Africa and Today

The immense body of contemporary work aimed at ‘promoting the rule of law’ is often accused of ‘neo-imperialism’. Yet, despite many points of contiguity between past and present legal interventions, the charge is overbroad and rarely illuminating. This article attempts to move beyond polemic to track concrete historical and structural forerunners of today's rule of law work. Focusing mainly (though not exclusively) on late imperial British endeavours, it traces colonial legal interventions over time, the techniques adopted (and rejected), the shifting normative bases of legitimacy, and moments of strategic recalibration in the face of resistance. Three broad attitudes towards law across the period are (provisionally) characterised as ‘regulative’, ‘constitutive’ and ‘institutive’ moments. In each phase, the Powers treat colonial territories as laboratories of statehood, within which experiments are conducted to locate the optimal configuration of law. In conclusion some counterparts to these moments in today's ‘rule of law’ activities are identified.

Field of study: Law
Composite and Surface Functionalization of Ultrafine-Grained Ti23Zr25Nb Alloy for Medical Applications

In this study, the ultrafine-grained Ti23Zr25Nb-based composites with 45S5 Bioglass and Ag, Cu, or Zn additions were produced by application of the mechanical alloying technique. Additionally, the base Ti23Zr25Nb alloy was electrochemically modified in the two stages of processing: electrochemical etching in the solution of H3PO4 and HF followed by electrochemical deposition in Ca(NO3)2, (NH4)2HPO4, and HCl. The in vitro cytocompatibility studies were also done with comparison to the commercially pure titanium. The established cell lines of Normal Human Osteoblasts (NHost, CC-2538) and Human Periodontal Ligament Fibroblasts (HPdLF, CC-7049) were used. The culture was conducted among the tested materials. Ultrafine-grained titanium-based composites modified with 45S5 Bioglass and Ag, Cu, or Zn metals have higher biocompatibility than the reference material in the form of a microcrystalline Ti. Proliferation activity was at a stable level with contact with studied materials. In vitro evaluation research showed that the ultrafine-grained Ti23Zr25Nb-based composites with 45S5 Bioglass and Ag, Cu, or Zn additions, with a Young modulus below 50 GPa, can be further used in the biomedical field.

Field of study: Materials science
The Allocation and Transfer of Control Rights between Capitalists and Entrepreneurs

The allocation of control rights in venture capital affects the firm's value and benefit of venture capitalists and entrepreneur.This paper analyzes how the control rights be allocated and transferred.We argue that the control rights should be a state- contingent control right,and the residual claim rights and residual control rights are independent and incompletely corresponding.The conclusions are consistent with the existing control theory and empirical evidences.

Field of study: Agricultural and Food sciences
Consistent Procedures for Cluster Tree Estimation and Pruning

For a density f on Rd, a high-density cluster is any connected component of {x : f (x) ≥ λ}, for some λ > 0. The set of all high-density clusters forms a hierarchy called the cluster tree of f . We present two procedures for estimating the cluster tree given samples from f . The first is a robust variant of the single linkage algorithm for hierarchical clustering. The second is based on the k-nearest neighbor graph of the samples. We give finite-sample convergence rates for these algorithms, which also imply consistency, and we derive lower bounds on the sample complexity of cluster tree estimation. Finally, we study a tree pruning procedure that guarantees, under milder conditions than usual, to remove clusters that are spurious while recovering those that are salient.

Field of study: Computer science
Spectropolarimetric observations of active galactic nuclei with the 6-m BTA telescope

We present the results of our spectropolarimetric observations for a number of active galactic nuclei (AGNs) carried out at the 6-m telescope with the SCORPIO focal reducer. The derived wavelength dependences of the polarization have been analyzed by taking into account the Faraday rotation of the polarization plane on the photon mean free path in a magnetized accretion disk. As a result, based on traditional accretion disk models, we have determined the magnetic field strength and distribution and a number of physical parameters of the accreting plasma in the region where the optical radiation is generated.

Field of study: Physics
SU-E-T-171: Pre-Treatment Radiotherapy Dose Verification Using Monte Carlo Doselet Modulation in a Spherical Phantom.

To design a robust pre-treatment dose verification tool for non-coplanar IMRT and VMAT radiotherapy treatments using electronic portal images (EPIs).



The method aims to modulate pre-calculated Monte Carlo (MC) doselets, leveraging symmetry in a spherical phantom. The patient-independent phase-space source MC model of a Varian 21 EX 6MV Clinac was used to transport particles. We utilized cylindrical symmetry of the phase-space above the jaws and azimuthally rotated its particles to lie along a radial strip. The strip was divided along the radius into 2mm (as projected to isocentre) segments, and the particles within each segment were used for dose calculation in a spherical water phantom via DOSXYZnrc, producing a doselet. For patient-dependent dose calculation in the spherical water phantom the doselets were redistributed to fill a treatment field, and then modulated based on a fluence maps derived from EPIs. Finally, gantry and couch rotations are applied. The spherical symmetry of the geometry makes this process simple and efficient.



A 10x10 cm2 open field was tested against BEAMnrc and DOSXYZnrc (∼1% uncertainty) in a spherical phantom with voxel size 1.25×1.25×1.25 mm3 . This passed a 3D gamma-index test with 98% agreement for 3%/3mm criteria above the 10% isodose, and calculated in 46s. A 7 field IMRT plan was calculated in 3.5 minutes on 2.5×2.5×2.5 mm3 resolution and was compared with results using the phase-space modulation method our group has published previously. The same gamma-index test achieved 97% agreement in this comparison. Timing results are based on a single 2.1 GHz processor.



Results demonstrate that our pre-treatment dose verification method can be used for efficient dose verification of non-coplanar treatments. Significant speed enhancements were achieved by utilizing phantom spherical symmetry in dose reconstruction.

Field of study: Medicine, Physics
C60, fullerenes, giant fullerenes and soot

During a series of experiments in which the nucleation of carbon vapour was studied in order to explore carbon chain and particle formation in stars the highly stable c60 molecule was detected. The properties of this molecule are in almost perfect accord with the proposal that the molecule has the closed cage buckminsterfullerene structure in which all 60 atoms are equivalent and lie at the corners of a truncated icosahedron, a shape familiar to many today in the form of the modern foot- or soccerball. This molecule is expected to be stabilised by geodesic and aromatic factors. The most important aspect of this discovery lies in the fact that such a symmetric object can form spontaneously from a chaotic, hot, carbon plasma. This novel conjecture is consistent with a wide range of observations on carbonaceous materials. The emphasis in this article is on those aspects of the c60 saga which pertain to non-planar organic chemistry both on earth and in space.

Field of study: Chemistry
Biotransformation of metoprolol by the fungus Cunninghamella blakesleeana

To investigate the biotransformation of metoprolol, a β1-cardioselective adrenoceptor antagonist, by filamentous fungus, and to compare the parallels between microbial transformation and mammalian metabolism.Five strains of Cunninghamella (C elegans AS 3.156, C elegans AS 3.2028, C echinulata AS 3.2004, C blakesleeana AS 3.153 and AS 3.910) were screened for the ability to transform metoprolol. The metabolites of metoprolol produced by C blakesleeana AS 3.153 were separated and assayed by liquid chromatography-tandem mass spectrometry (LC/MSn). The major metabolites were isolated by semipreparative HPLC and the structures were identified by a combination of LC/MSn and nuclear magnetic resonance analysis.Metoprolol was transformed to 7 metabolites; 2 were identified as new metabolites and 5 were known metabolites in mammals.The microbial transformation of metoprolol was similar to the metabolism in mammals. The fungi belonging to Cunninghamella species could be used as complementary models for predicting in vivo metabolism and producing quantities of metabolite references for drugs like metoprolol.

Field of study: Biology, Chemistry, Medicine