bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effect of a primordial magnetic field on the inflaton decay process in a warm inflation scenario
Authors: Bastero‐Gil M. , Piccinelli G. , Sanchez A. 
Published: November 2015

AbstractMagnetic fields appear everywhere in the Universe. Their widespread presence at high redshifts and very large scales suggests that their origin could be primordial. In particular, their presence during the inflationary epoch can certainly not be ruled out. In the warm inflation scenario, the coupling of the inflaton to other bosonic and fermionic fields gives rise to dissipative effects that modify the inflationary dynamics. Since primordial magnetic fields could have an effect on both the effective inflationary potential and the inflaton decay process, their contribution must be considered together with the finite temperature corrections. We review here their effect on the inflationary potential and present preliminary results of their intervention in the dissipation process. (© 2015 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Stable emergent Universe – a creation without Big‐Bang
Authors: Guendelman E. , Herrera R. , Labrana P. , Nissimov E. , Pacheva S. 
Published: November 2015

AbstractBased on an earlier introduced new class of generalized gravity‐matter models defined in terms of two independent nonRiemannian volume forms (alternative generally covariant integration measure densities) on the space‐time manifold, we derive an effective “Einstein‐frame” theory featuring the following remarkable properties: (i) We obtain effective potential for the cosmological scalar field possessing two infinitely large flat regions which allows for a unified description of both early Universe inflation as well as of present dark energy epoch; (ii) for a specific parameter range the model possesses a non‐singular stable “emergent Universe” solution which describes an initial phase of evolution that precedes the inflationary phase. (© 2015 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Status of the LHC experiments and Standard‐Model result highlights
Authors: Biino C. 
Published: November 2015

AbstractIn this overview presentation I report on selected Standard Model (SM) physics highlights obtained by the ATLAS and CMS experiments in the first three years of data taking (Run I) at the new Large Hadron Collider (LHC) at CERN. By far the most important and exciting result of LHC Run I has been the observation of a new boson with a mass of 125 GeV, consistent with the properties of the SM Higgs boson. The discovery of the Higgs boson has brought the last missing piece of the Standard Model but the talk has given also an overview of the main results on di‐boson production, heavy flavour physics (b‐quark rare decays and CP violation; top‐quark mass and properties) and QCD. Finally a brief discussion on LHC future program. LHC is just now restarting operation at higher energy. New data will certainly give more detailed informations on the Higgs boson and by the end of this decade LHC experiments will have collected ten times more proton‐proton (pp) collisions. The Standard Model processes have been holding up to scrutiny over several orders of magnitude in production cross section but we are just at the beginning of the TeV scale exploration. (© 2015 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Search for new physics at the LHC and prospects for new discoveries
Authors: Conti G. 
Published: November 2015

AbstractThe Large Hadron Collider (LHC) at CERN has allowed the ATLAS and CMS experiments to collect a large amount of proton‐proton collision data at 7 TeV and 8 TeV centre‐of‐mass energies. This dataset was used to discover a Higgs boson with Standard Model‐like properties at a mass of about 125 GeV. In parallel, an impressive number of searches for deviations from the Standard Model expectations have been carried out in various physics areas (BSM Higgs, Supersymmetry, and Exotics). Representative searches in all of these domains will be presented and their impact on theoretical models beyond the SM assessed. To date, there is no evidence in the LHC data of a signal for New Physics beyond the SM. However, a few legacy 2–3δ deviations remain from both experiments. After an 18‐month shutdown, the LHC is about to deliver collision data at an increased centre‐of‐mass energy of 13 TeV. The large increase in collision energy will provide much improved sensitivity for various searches, in particular for high mass particles. (© 2015 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Magnetic field decay in normal radio pulsars
Authors: Igoshev A.P. , Popov S.B. 
Published: November 2015

AbstractWe analyse the origin of the magnetic field decay in normal radio pulsars found by us in a recent study. This decay has a typical time scale ∼4×105 yr and operates in the range ∼105– few×105 yr. We demonstrate that this field evolution may be either due to the Ohmic decay related to the scattering from phonons, or due to the Hall cascade which reaches the Hall attractor. According to our analysis, the first possibility seems to be more reliable. So, we attribute the discovered field decay mainly to the Ohmic decay by phonons, which is saturated at the age of a few×105 yr when a neutron star cools down to the critical temperature below which the phonon scattering does not contribute much to the resistivity of the crust. Some role of the Hall effect and attractor is not excluded, and will be analysed in our further studies. (© 2015 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
4U 1746–37: An ultra‐low‐mass compact star candidate
Authors: Li Zhao‐Sheng 
Published: November 2015

AbstractThe Rossi X‐ray Timing Explorer observed three photospheric radius expansion bursts in 4U 1746‐37, all with low touchdown fluxes. We discuss the possibiity of a low‐mass neutron star in 4U 1746‐37 if the touchdown flux corresponds to its Eddington limit. 4U 1746‐37 is a dipping binary system which has a high inclination angle. Two geometric effects, the reflection of the far side accretion disc and the obscuration of the near side accretion disc have also been included. We apply a Monte‐Carlo simulation, with typical values of hydrogen mass fraction and color correction factor, to constrain the mass and radius of the neutron star in 4U 1746‐37. We found that the mass of 4U 1746‐37 is 0.41+0.70–0.30 M® at 99.7 % confidence which is an ultra‐low‐mass compact star candidate. It could be reproduced by a self‐bound compact star, i.e., quark star or quark‐cluster star, from an ccretion‐induced collapse process. (© 2015 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Chiral imbalance induced by longitudinal photons in a charged magnetized QED plasma
Authors: Acosta Avalo J. L. , Pérez Rojas H. 
Published: November 2015

AbstractWe demonstrate the existence of a chiral magnetic effect in an electron‐positron magnetized gas in QED. A vector current is induced by the electric field related to the pseudo‐vector longitudinal Debye massive photon mode propagating along the external magnetic field B and separating opposite charges of the same helicity. A equation associated to the nonconservation of the axial current is obtained in a medium of massive and magnetized charged fermions. The effect is interesting in connection to the QCD chiral magnetic case reported in current literature. (© 2015 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
On propagation of photons in a magnetized medium
Authors: Cruz Rodríguez L. , Pérez Martínez A. , Pérez Rojas H. , Rodríguez Querts E. 
Published: November 2015

AbstractThe aim of this work is to solve the dispersion relations near the first excitation threshold of a photon propagating along a magnetic field in the strong field limit. We have calculated the time damping of the photon in two particular cases: the degenerate gas as well as the diluted gas limit, both being important from the astro‐physical point of view. In particular, the diluted gas limit could describe the magnetosphere of neutron stars. The solutions have been used to obtain a finite quantum Faraday angle in both limits. A resonant behavior for the Faraday angle is also obtained. To reproduce the semi‐classical result for the Faraday rotation angle, the weak field limit is considered. (© 2015 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Interplanetary GPS using pulsar signals
Authors: Becker W. , Bernhardt M. G. , Jessner A. 
Published: November 2015

AbstractAn external reference system suitable for deep space navigation can be defined by fast spinning and strongly magnetized neutron stars, called pulsars. Their beamed periodic signals have timing stabilities comparable to atomic clocks and provide characteristic temporal signatures that can be used as natural navigation beacons, quite similar to the use of GPS satellites for navigation on Earth. By comparing pulse arrival times measured on‐board a spacecraft with predicted pulse arrivals at a reference location, the spacecraft position can be determined autonomously and with high accuracy everywhere in the solar system and beyond. The unique properties of pulsars make clear already today that such a navigation system will have its application in future astronautics. In this paper we describe the basic principle of spacecraft navigation using pulsars and report on the current development status of this novel technology. (© 2015 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Hybrid chitosan–ß‐glycerol phosphate–gelatin nano‐/micro fibrous scaffolds with suitable mechanical and biological properties for tissue engineering
Authors: Lotfi Marzieh , Bagherzadeh Roohollah , Naderi‐Meshkin Hojjat , Mahdipour Elahe , Mafinezhad Asghar , Sadeghnia Hamid Reza , Esmaily Habibollah , Maleki Masoud , Hasssanzadeh Halimeh , Ghayaour‐Mobarhan Majid , Bidkhori Hamid Reza , Bahrami Ahmad Reza 
Published: November 2015

ABSTRACTScaffold‐based tissue engineering is considered as a promising approach in the regenerative medicine. Graft instability of collagen, by causing poor mechanical properties and rapid degradation, and their hard handling remains major challenges to be addressed. In this research, a composite structured nano‐/microfibrous scaffold, made from a mixture of chitosan–ß‐glycerol phosphate–gelatin (chitosan–GP–gelatin) using a standard electrospinning set‐up was developed. Gelatin–acid acetic and chitosan ß‐glycerol phosphate–HCL solutions were prepared at ratios of 30/70, 50/50, 70/30 (w/w) and their mechanical and biological properties were engineered. Furthermore, the pore structure of the fabricated nanofibrous scaffolds was investigated and predicted using a theoretical model. Higher gelatin concentrations in the polymer blend resulted in significant increase in mean pore size and its distribution. Interaction between the scaffold and the contained cells was also monitored and compared in the test and control groups. Scaffolds with higher chitosan concentrations showed higher rate of cell attachment with better proliferation property, compared with gelatin‐only scaffolds. The fabricated scaffolds, unlike many other natural polymers, also exhibit non‐toxic and biodegradable properties in the grafted tissues. In conclusion, the data clearly showed that the fabricated biomaterial is a biologically compatible scaffold with potential to serve as a proper platform for retaining the cultured cells for further application in cell‐based tissue engineering, especially in wound healing practices. These results suggested the potential of using mesoporous composite chitosan–GP–gelatin fibrous scaffolds for engineering three‐dimensional tissues with different inherent cell characteristics. © 2015 Wiley Periodicals, Inc. Biopolymers 105: 163–175, 2016.
p53 R175H hydrophobic patch and H‐bond reorganization observed by MD simulation
Authors: Thayer Kelly M. , Quinn Taylor R. 
Published: November 2015

ABSTRACTMolecular dynamics simulations probe the origins of aberrant functionality of R175H p53, which normally prevent tumorigenesis. This hotspot mutation exhibits loss of its essential zinc cofactor, aggregation, and activation of gain of function promoters, characteristics contributing to the loss of normal p53 activity. This study provided molecular level insight into the reorganization of the hydrogen bonding network and the formation of a hydrophobic patch on the surface of the protein. The hydrogen bonding network globally redistributes at the expense of the stability of the β‐sandwich structure, and surface residues reorganize to expose a 250 Å2 hydrophobic patch of residues covering approximately 2% of the solvent accessible surface. These changes could both stabilize the protein in the conformation exposing the patch to solvent to mediate the reported aggregation, and cause a destabilization in the area associated with DNA binding residues to affect the specificity. The development of the patch prior to loss of zinc indicates that stabilizing the patch quickly may prevent zinc loss. Considerations for rational design of small molecule therapeutics in light of the structural insight has been discussed and it suggest the positive ring around the hydrophobic patch and conserved residues may constitute a druggable site. © 2015 Wiley Periodicals, Inc. Biopolymers 105: 176–185, 2016.
C‐terminus of a hexapeptidic ghrelin receptor inverse agonist can switch peptide behavior from inverse agonism to agonism
Authors: Els‐Heindl Sylvia , Bellmann‐Sickert Kathrin , Beck‐Sickinger Annette G. 
Published: November 2015

ABSTRACTSubtle changes in the sequence at the N‐terminus and in the aromatic core of hexapeptidic ghrelin receptor inverse agonists can switch behavior from inverse agonism to agonism, but the C‐terminal role of the sequence is unclear. Thus, analogs of the ghrelin receptor inverse agonist KbFwLL‐NH2 (b = β‐(3‐benzothienyl)‐d‐alanine) were synthesized by solid phase peptide synthesis in order to identify the influence of aromaticity, charge, and hydrophobicity. Potency and efficacy of the hexapeptides were evaluated in inositol triphosphate turnover assays. Notably, modifications directly at the C‐terminal Leu6 could influence peptide efficacy leading to decreased constitutive activity. High hydrophobicity at the C‐terminal position was of importance for elevated inverse agonist activity, the introduction of charged amino acids led to decreased potency. In contrast, structure–activity relationship studies of Leu5 located closer to the aromatic core revealed an agonism‐inducing position. These findings imply that amino acids with possible cation–π or π–π interactions and a suitable orientation at the C‐terminus of the aromatic core induce agonism. Receptor binding studies showed that most peptides bind to the receptor at a concentration of 1 µM and modification directly at the C‐terminus is generally more accepted than Leu5 substitution. Interestingly, this observation is not dependent on the type of modification. These studies reveal another switch region of the short ghrelin receptor ligand pointing out the sensitivity of the ghrelin receptor binding pocket. © 2015 Wiley Periodicals, Inc. Biopolymers (Pept Sci) 106: 101–108, 2016.
Synthesis of chiral five‐membered carbocyclic ring amino acids with an acetal moiety and helical conformations of its homo‐chiral homopeptides
Authors: Koba Yurie , Hirata Yoko , Ueda Atsushi , Oba Makoto , Doi Mitsunobu , Demizu Yosuke , Kurihara Masaaki , Tanaka Masakazu 
Published: November 2015

ABSTRACTChiral five‐membered carbocyclic ring amino acids bearing various diol acetal moieties were synthesized starting from l‐malic acid, and homo‐chiral homopeptides composed of cyclic amino acid (S)‐Ac5c3EG bearing an ethylene glycol acetal, up to an octapeptide, were prepared. A conformational analysis revealed that (S)‐Ac5c3EG homopeptides formed helical structures. (S)‐Ac5c3EG homopeptides, up to hexapeptides, formed helical structures without controlling the helical screw direction, while (S)‐Ac5c3EG hepta‐ and octapeptides formed helical structures with a preference for the left‐handed (M) helical‐screw direction. © 2015 Wiley Periodicals, Inc. Biopolymers (Pept Sci) 106: 555–562, 2016.
Identification of a degrading enzyme in human serum that hydrolyzes a C‐terminal core sequence of neuromedin U
Authors: Takayama Kentaro , Taguchi Akihiro , Yakushiji Fumika , Hayashi Yoshio 
Published: November 2015

ABSTRACTNeuromedin U (NMU), an anorexigenic peptide, has attracted attention as a candidate for development of drugs against obesity. We recently developed several potent hexapeptidic agonists derived from NMU that share a common Pro‐Arg‐Asn‐NH2 (PRN) sequence at their C‐termini and found that the amide bond between Arg and Asn is rapidly degraded in serum. In this study, we determined that the key enzyme responsible for this biodegradation was thrombin. Both irreversible and reversible thrombin inhibitors (PPACK and argatroban, respectively) enhanced the serum stability of both hexapeptidic agonists and human NMU itself as an inherent ligand. In addition, rapid degradation did not occur in citrated human plasma because thrombin was not activated under these conditions. Furthermore, we found that an N‐terminal 2‐thienylacetyl group in hexapeptidic agonists enhanced recognition by thrombin. These findings will be valuable for future investigations of the biological functions of NMU in vivo. © 2015 Wiley Periodicals, Inc. Biopolymers (Pept Sci) 106: 440–445, 2016.
Design and testing of an assessment instrument to measure understanding of protein structure and enzyme inhibition in a new context
Authors: Villafañe Sachel M. , Heyen Bruce J. , Lewis Jennifer E. , Loertscher Jennifer , Minderhout Vicky , Arnold Murray Tracey 
Published: November 2015

AbstractAssessment instruments designed to measure student conceptual understanding and skills proficiency related to biochemistry are important to transform undergraduate biochemistry education. The purpose of this study was to develop an assessment instrument to measure student understanding of protein structure and enzyme inhibition in a new context, that of saturable binding. A community of biochemistry educators was involved in an iterative process of designing and testing of this assessment, which consists of true/false and open‐ended questions that map to low and high levels in Bloom's taxonomy. A total of 188 students' responses were collected from seven different institutions and were graded by two independent raters using a rubric. Results from this administration indicate that most students were able to answer the questions related to lower‐levels in Bloom's taxonomy; however for higher‐level questions, students had more difficulty. The results from this assessment can give instructors insight into the ways in which persistent incorrect or incomplete ideas related to protein structure and binding events can hinder knowledge application. Also, the use of a community of practice to develop assessment instruments of this type and the format of the instrument itself could be a useful model for development of assessment instruments in the future. © 2015 by The International Union of Biochemistry and Molecular Biology, 44:179–190, 2016.
Iron–Carbonyl Aqueous Vesicles (MCsomes) by Hydration of [Fe(CO){CO(CH2)5CH3}(Cp)(PPh3)] (FpC6): Highly Integrated Colloids with Aggregation‐Induced Self‐Enhanced IR Absorption (AI‐SEIRA)
Authors: Murshid Nimer , Wang Xiaosong 
Published: November 2015

AbstractSelf‐assembly of hydrophobic molecules into aqueous colloids contradicts common chemical intuition, but has been achieved through hydration of [Fe(CO){CO(CH2)5CH3}(Cp)(PPh3)] (FpC6). FpC6 has no surface activity, no NMR signals in D2O and no critical aggregation concentration (CAC) in H2O. The molecule, however, contains both acyl and terminal CO groups that are prone to being hydrated. By adding water to a solution in THF, self‐assembly of FpC6 can be initiated through water–carbonyl interactions (WCIs) with the highly polarized acyl CO groups. This aggregation subsequently enhances the hydration of the acyl CO groups and also induces the WCI of otherwise unhydrated terminal CO groups. The resultant metal–carbonyl aggregates have been proved to be bilayer vesicles with iron complexes exposed towards water and alkyl chains forming inner walls (MCsomes). These MCsomes show high structure integration upon dilution due to the hydrophobic nature of the building blocks. The highly polarized CO groups on the surface of the MCsomes result in a negative zeta potential (−65 mV) and create a local electric field, which significantly enhances the IR absorption of CO groups by more than 100‐fold. This is the first discovery of aggregation‐induced self‐enhanced IR absorption (AI‐SRIRA) without the assistant of external dielectric substrates. Highly integrated MCsomes are, therefore, promising as a novel group of materials, for example, for IR‐based sensing and imaging.
Coating Platinum Nanoparticles with Methyl Radicals: Effects on Properties and Catalytic Implications
Authors: Bar‐Ziv Ronen , Zilbermann Israel , Shandalov Michael , Shevchenko Vladimir , Meyerstein Dan 
Published: November 2015

AbstractIt was recently reported that the reaction of methyl radicals with Pt0 nanoparticles (NPs), prepared by the reduction of Pt(SO4)2 with NaBH4, is fast and yields as the major product stable (Pt0‐NPs)(CH3)n and as side products, in low yields, C2H6, C2H4, and some oligomers. We decided to study the effect of this coating on the properties of the Pt0‐NPs. The results show that the coating can cover up to 75 % of the surface Pt0 atoms. The rate constant of the reaction, k(.CH3+Pt0‐NPs), decreases with the increase in the surface coverage, leading to competing reaction paths in the solution, which gradually become dominant, affecting the composition of the products. The methyl coating also affects the zeta potential, the UV spectra, and the electrocatalytic reduction of water in the presence of the NPs. Thus, the results suggest that binding alkyl radicals to Pt0 surfaces might poison the NPs catalytic activity. When the Pt0‐NPs are prepared by the reduction of a different precursor salt, PtCl62−, nearly no C2H4 and oligomers are formed and the methyl coating covers a larger percentage of the surface Pt0 atoms. The difference is attributed to the morphology of the Pt0‐NPs: those prepared from Pt(SO4)2 are twinned nanocrystals, whereas those prepared from PtCl62− consist mostly of single crystals. Thus, the results indicate that the side products, or most of them at least, are formed on the twinned Pt0 nanocrystal edges created between (111) facets. In addition, the results show that Pt0‐NPs react very differently compared with other noble metals, for example, Au0 and Ag0; this difference is attributed in part to the difference in the bond strength, (M0‐NP)CH3, and should be considered in heterogeneous catalytic processes involving alkyl radicals as intermediates.