bluuebunny/crossref_metadata_2025_split huggingface dataset:
Nuclear Reactions
Authors: Bertulani Carlos A. 
Published: April 2014

AbstractNuclear reactions generate energy in nuclear reactors, in stars, and are responsible for the existence of all elements heavier than hydrogen in the Universe. Nuclear reactions denote reactions between nuclei, and between nuclei and other fundamental particles, such as electrons and photons. A short description of the conservation laws and the definition of basic physical quantities is presented, followed by a more detailed account of specific cases: (i) formation and decay of compound nuclei; (ii)direct reactions; (iii) photon and electron scattering; (iv) heavy ion collisions; (v) formation of a quark–gluon plasma; (vi) thermonuclear reactions; and (vii) reactions with radioactive beams. Whenever necessary, basic equations are introduced to help understand general properties of these reactions.
Neutrino Astrophysics
Authors: Haxton Wick C. 
Published: April 2014

AbstractThe field of neutrino astrophysics is reviewed, including basic neutrino properties, solar neutrinos (the standard solar model, helioseismology, and recent experimental results); neutrino mass, oscillations, and matter effects; atmospheric neutrinos; open questions in neutrino physics, such as the neutrino mass hierarchy,charge parity(CP) violation, and the absolute scale of neutrino masses; supernovae, including the explosion mechanism, the exotic matter effects that can influence neutrino propagation, and the neutrino role in energy transport and nucleosynthesis; neutrino cooling in red giants and connections to new neutrino properties such as magnetic moments; and high‐energy astrophysical neutrinos, their production in cosmic rays interactions and possible associations with cosmic‐ray point sources, and new high‐energy neutrino detectors such as IceCube.
Optics and Nuclear Photonics
Authors: Habs Dietrich 
Published: April 2014

AbstractOur discovery that the scattering of γ quanta from the very large electric fields of nuclei, calledDelbrück scattering, results in a much larger real part of the index of refraction for γ‐rays than anticipated has manifold consequences. All older perturbativequantum electrodynamics(QED) predictions for a few million electronvolt γ‐rays by the first‐order Born approximation fail by many orders of magnitude and a new, more complex nonperturbative QED has to be applied. As the expected cross sections are now much larger, other nonperturbative high‐field QED effects such as photon splitting or an enhanced pair production close to the threshold are being investigated to study and understand this new high‐field QED with the ultrahigh electric fields of the nucleus. At the same time, the much larger Delbrück scattering allows to develop γ‐ray optics of up to about 10 MeV, with new focusing lenses and much more efficient γ monochromators. In combination with the development of much more intense, brilliant γ beams, this opens a new field of nuclear photonics. We, for the first time, will selectively excite individual nuclear levels for diagnostics of isotopes or their transmutation. The strongly penetrating γ beams focused to micrometer diameters open up new fields of diagnostics in medicine, green energy, nuclear waste management, and so on. We can produce about 50 new medical radioisotopes for cancer therapy or for the diagnostics of dose delivery to the tumor. Also, other brilliant secondary sources, such as cold neutron sources or moderated positron beams, can be produced, which open new ways for material or surface sciences.
Nuclear Astrophysics
Authors: Schatz Hendrik 
Published: April 2014

AbstractNuclear astrophysics aims at understanding the nuclear reaction processes that occur naturally in the cosmos and shape much of the visible universe. These nuclear processes make the stars shine, they power stellar explosions, and they are responsible for the origin of the elements, defining the relative proportions of elements available for life. This chapter highlights the direct connections between nuclear physics and astrophysics in a wide range of astrophysical environments and how the nuclear physics needed to understand the cosmos can be obtained from nuclear theory and nuclear physics experiments.
New MT‐ND6 and NDUFA1 mutations in mitochondrial respiratory chain disorders
Authors: Uehara Natsumi , Mori Masato , Tokuzawa Yoshimi , Mizuno Yosuke , Tamaru Shunsuke , Kohda Masakazu , Moriyama Yohsuke , Nakachi Yutaka , Matoba Nana , Sakai Tetsuro , Yamazaki Taro , Harashima Hiroko , Murayama Kei , Hattori Keisuke , Hayashi Jun‐Ichi , Yamagata Takanori , Fujita Yasunori , Ito Masafumi , Tanaka Masashi , Nibu Ken‐ichi , Ohtake Akira , Okazaki Yasushi 
Published: April 2014

AbstractObjectiveMitochondrial respiratory chain disorder (MRCD) is an intractable disease of infants with variable clinical symptoms. Our goal was to identify the causative mutations in MRCD patients.MethodsThe subjects were 90 children diagnosed with MRCD by enzyme assay. We analyzed whole mitochondrial DNA (mtDNA) sequences. A cybrid study was performed in two patients. Whole exome sequencing was performed for one of these two patients whose mtDNA variant was confirmed as non‐pathogenic.ResultsWhole mtDNA sequences identified 29 mtDNA variants in 29 patients (13 were previously reported, the other 13 variants and three deletions were novel). The remaining 61 patients had no pathogenic mutations in their mtDNA. Of the 13 patients harboring unreported mtDNA variants, we excluded seven variants by manual curation. Of the remaining six variants, we selected two Leigh syndrome patients whose mitochondrial enzyme activity was decreased in their fibroblasts and performed a cybrid study. We confirmed that m.14439G>A (MT‐ND6) was pathogenic, while m.1356A>G (mitochondrial 12S rRNA) was shown to be a non‐pathogenic polymorphism. Exome sequencing and a complementation study of the latter patient identified a novel c.55C>T hemizygous missense mutation in the nuclear‐encoded gene NDUFA1.InterpretationOur results demonstrate that it is important to perform whole mtDNA sequencing rather than only typing reported mutations. Cybrid assays are also useful to diagnose the pathogenicity of mtDNA variants, and whole exome sequencing is a powerful tool to diagnose nuclear gene mutations as molecular diagnosis can provide a lead to appropriate genetic counseling.
Irreversible Denaturation of Proteins through Aluminum‐Induced Formation of Backbone Ring Structures
Authors: Song Bo , Sun Qian , Li Haikuo , Ge Baosheng , Pan Ji Sheng , Wee Andrew Thye Shen , Zhang Yong , Huang Shaohua , Zhou Ruhong , Gao Xingyu , Huang Fang , Fang Haiping 
Published: April 2014

AbstractA combination of ab initio calculations, circular dichroism, nuclear magnetic resonance, and X‐ray photoelectron spectroscopy has shown that aluminum ions can induce the formation of backbone ring structures in a wide range of peptides, including neurodegenerative disease related motifs. These ring structures greatly destabilize the protein and result in irreversible denaturation. This behavior benefits from the ability of aluminum ions to form chemical bonds simultaneously with the amide nitrogen and carbonyl oxygen atoms on the peptide backbone.
Control of the Conductance of Engineered Protein Nanopores through Concerted Loop Motions
Authors: Zhuang Tiandi , Tamm Lukas K. 
Published: April 2014

AbstractProtein nanopores have attracted much interest for nucleic acid sequencing, chemical sensing, and protein folding at the single molecule level. The outer membrane protein OmpG from E. coli stands out because it forms a nanopore from a single polypeptide chain. This property allows the separate engineering of each of the seven extracellular loops that control access to the pore. The longest of these loops, loop 6, has been recognized as the main gating loop that closes the pore at low pH values and opens it at high pH values. A method was devised to pin each of the loops to the embedding membrane and measure the single‐pore conductances of the resulting constructs. The electrophysiological and complementary NMR measurements show that the pinning of individual loops alters the structure and dynamics of neighboring and distant loops in a correlated fashion. Pinning loop 6 generates a constitutively open pore and patterns of concerted loop motions control access to the OmpG nanopore.
Säurekatalysierte oxidative Radikaladdition von Ketonen an Olefine
Authors: Schweitzer‐Chaput Bertrand , Demaerel Joachim , Engler Hauke , Klussmann Martin 
Published: April 2014

AbstractAuf Basis einer mechanistischen Untersuchung haben wir eine Brønsted‐Säure‐katalysierte Bildung von Ketonradikalen entdeckt, die vermutlich über thermolabile Alkenylperoxide verläuft, welche in situ aus Ketonen und Hydroperoxiden gebildet werden. Diese Entdeckung wurde für eine Mehrkomponentenradikaladdition von nichtaktivierten Ketonen und tert‐Butylhydroperoxid an Olefine genutzt. Die erhaltenen γ‐Peroxyketone sind synthetisch nützliche Intermediate, welche zu 1,4‐Diketonen, Homoaldolprodukten oder Alkylketonen weiter umgesetzt werden können; in einem Eintopfverfahren gelang auch die Bildung eines pharmakologisch aktiven Pyrrols.
Control of the Electronic Ground State on an Electron‐Transfer Copper Site by Second‐Sphere Perturbations
Authors: Morgada Marcos N. , Abriata Luciano A. , Zitare Ulises , Alvarez‐Paggi Damian , Murgida Daniel H. , Vila Alejandro J. 
Published: April 2014

AbstractThe CuA center is a dinuclear copper site that serves as an optimized hub for long‐range electron transfer in heme–copper terminal oxidases. Its electronic structure can be described in terms of a σu* ground‐state wavefunction with an alternative, less populated ground state of πu symmetry, which is thermally accessible. It is now shown that second‐sphere mutations in the CuA containing subunit of Thermus thermophilus ba3 oxidase perturb the electronic structure, which leads to a substantial increase in the population of the πu state, as shown by different spectroscopic methods. This perturbation does not affect the redox potential of the metal site, and despite an increase in the reorganization energy, it is not detrimental to the electron‐transfer kinetics. The mutations were achieved by replacing the loops that are involved in protein–protein interactions with cytochrome c, suggesting that transient protein binding could also elicit ground‐state switching in the oxidase, which enables alternative electron‐transfer pathways.
Enantioselective Total Synthesis of (−)‐Lansai B and (+)‐Nocardioazines A and B
Authors: Wang Haoxuan , Reisman Sarah E. 
Published: April 2014

AbstractThe concise total syntheses of the bis(pyrroloindolines) (−)‐lansai B and (+)‐ nocardioazines A and B are reported. The key pyrroloindoline building blocks are rapidly prepared by enantioselective formal [3+2] cycloaddition reactions. The macrocycle of (+)‐nocardioazine A is constructed by an unusual intramolecular diketopiperazine formation.
Dithiolodithiole as a Building Block for Conjugated Materials
Authors: Schipper Derek J. , Moh Lionel C. H. , Müller Peter , Swager Timothy M. 
Published: April 2014

AbstractThe development of new conjugated organic materials for dyes, sensors, imaging, and flexible light emitting diodes, field‐effect transistors, and photovoltaics has largely relied upon assembling π‐conjugated molecules and polymers from a limited number of building blocks. The use of the dithiolodithiole heterocycle as a conjugated building block for organic materials is described. The resulting materials exhibit complimentary properties to widely used thiophene analogues, such as stronger donor characteristics, high crystallinity, and a decreased HOMO–LUMO gap. The dithiolodithiole (C4S4) motif is readily synthetically accessible using catalytic processes, and both the molecular and bulk properties of materials based on this building block can be tuned by judicious choice of substituents.
Production of biodegradable polyesters via enzymatic polymerization and solid state finishing
Authors: Kanelli Maria , Douka Aliki , Vouyiouka Stamatina , Papaspyrides Constantine D. , Topakas Evangelos , Papaspyridi Lefki‐Maria , Christakopoulos Paul 
Published: April 2014

ABSTRACTThe synthesis of aliphatic polyesters (PEs) derived from diols (1,4‐butanediol and 1,8‐octanediol) and diacids or their derivatives (diethyl succinate, sebacic acid, 1,12‐dodecanedioic acid, and 1,14‐tetradecanedioic acid) was achieved in order to produce poly(butylene succinate) (PE 4.4), poly(octylene sebacate) (PE 8.10), poly(octylene dodecanate) (PE 8.12), and poly(octylene tetradecanate) (PE 8.14). The herein suggested procedure involved two stages, both sustainable and in accordance with the principles of “green” polymerization. The first comprised an enzymatic prepolymerization under vacuum, in the presence of diphenylether as solvent using Candida antarctica lipase B as biocatalyst, whereas a low‐temperature postpolymerization step [solid state polymerization (SSP)] followed in order to upgrade the PEs quality. In the enzymatically synthesized prepolymers, the range of number–average molecular weight attained was from 3700 to 8000 g/mol with yields reaching even 97%. Subsequently, SSP of PE 4.4 and 8.12 took place under vacuum or flowing nitrogen and lasted 10–48 h, at temperatures close to the prepolymer melting point (Tm − TSSP varied between 4°C and 14°C). The solid state finishing led to increase in the molecular weight depending on the prepolymer type, and it also contributed to improvement of the physical characteristics and the thermal properties of the enzymatically synthesized PEs. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40820.
Thermal–oxidative degradation and accelerated aging behavior of polyamide 6/epoxy resin‐modified montmorillonite nanocomposites
Authors: Xia Lei , Xiong Jinsu , Shentu Baoqing , Weng Zhixue 
Published: April 2014

ABSTRACTPolyamide 6 (PA6) nanocomposites based on epoxy resin‐modified montmorillonite (EP‐MMT) were prepared by melt processing using a typical twin‐screw extruder. X‐ray diffraction combined with transmission electron microscopy was applied to elucidate the structure and morphology of PA6/EP‐MMT nanocomposites, suggesting a nearly exfoliated structure in the nanocomposite with 2 wt % EP‐MMT (PA6/2EP‐MMT) and a partial exfoliated‐partial intercalated structure in PA6/4 wt %EP‐MMT nanocomposite (PA6/4EP‐MMT). The thermogravimetric analysis under air atmosphere was conducted to characterize the thermal–oxidative degradation behavior of the material, and the result indicated that the presence of EP‐MMT could inhibit the thermal‐oxidative degradation of PA6 effectively. Accelerated heat aging in an air circulating oven at 150°C was applied to assess the thermal–oxidative stability of PA6 nanocomposites through investigation of reduced viscosity, tensile properties, and chemical structure at various time intervals. The results indicated that the incorporation of EP‐MMT effectively enhanced the thermal–oxidative stability of PA6, resulting in the high retention of reduced viscosity and tensile strength, and the low ratio of terminal carboxyl group to amino group. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40825.
Fabrication of PAN/PHCS adsorptive UF membranes with enhanced performance for dichlorophenol removal from water
Authors: Gao Yan , Qiao Yuan , Yang Sen 
Published: April 2014

ABSTRACTA series of novel polyacrylonitrile (PAN) adsorptive UF membranes were prepared via the nonsolvent induced phase inversion method using adsorbent‐amphiphilic porous hollow carbonaceous microspheres (PHCSs) as additive. The resulted PAN/PHCS membranes were demonstrated to have better mechanical strength than the pure PAN membrane. The water fluxes of the PAN/PHCS membranes were slightly decrease; however, the rejections to pepsin were maintained at a high level (81–86%). The properties of the PAN/PHCS membranes for 2,4‐dichlorophenol removal from water were investigated. The results showed that 2,4‐dichlorophenol could be rapidly removed from water via adsorption mechanism by PAN/PHCS membranes, and the maximum reduction efficiency was up to 70%. The adsorption of 2,4‐dichlorophenol to the membranes was reversible and the membranes could be regenerated facilely by water washing. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40837.
Genetic diversity of two Philippine native freshwater goby species (Perciformes: Gobiidae): implications for conservation
Authors: Ardestani Goli , Rogelio Diana Rose O. , Reyes Roberto C. , Laude Rita P. 
Published: April 2014

ABSTRACTAppropriate decision‐making in conservation programmes requires an understanding of the population genetic structure of various indigenous species. However, in lake and river ecosystems rated as biodiversity conservation priority areas in the Philippines, the diversity of many species remains uncharacterized.To address the existing gap, genetic diversity of two native freshwater fishes, Glossogobius celebius (Valenciennes, 1837) and Glossogobius giuris (Hamilton, 1822) was measured. Genetic structure and estimates of genetic variation for each species was determined using isozyme analysis.A higher level of genetic variation was observed within G. celebius populations compared with G. giuris. Genetic structure indicated that the observed genetic variation in G. giuris is due to the variation among the populations. The results suggest the presence of geographical barriers even in adjacent aquatic ecosystems that could restrict gene flow among G. giuris populations.This study supports the need for immediate conservation interventions for both species as they show a low level of genetic diversity in addition to being threatened in their own environment. Possible measures include translocation and establishment of a refuge population of the species studied to be complemented with location‐specific strategies that would enhance their habitat conditions. In addition, education and enhancing the awareness of the local community regarding habitat protection are strongly recommended. Copyright © 2014 John Wiley & Sons, Ltd.
Homogeneous Oxidation of Water by Iron Complexes with Macrocyclic Ligands
Authors: Zhang Biaobiao , Li Fei , Yu Fengshou , Cui Honghua , Zhou Xu , Li Hua , Wang Yong , Sun Licheng 
Published: April 2014

AbstractThe activity of eleven separated iron complexes and nine in situ‐generated iron complexes towards catalytic water oxidation have been examined in aqueous solutions with Ce(NH4)2(NO3)6 as the oxidant. Two iron complexes bearing tridentate and tetradentate macrocyclic ligands were found to be novel water oxidation catalysts. The one with tetradentate ligand exhibited a promising activity with a turnover number of 65 for oxygen evolution.
Physician‐Commanded Six‐DOF Robotic Manipulation for Target Localization in Conformal Radiotherapy
Authors: Chang Wen‐Chung , Chen Chin‐Sheng , Liu Chia‐Yuan , Chen Yu‐Jen 
Published: April 2014

AbstractTo effectively improve treatment precision in conformal radiotherapy, ultrasound sensing is employed to detect tumors in real time. In order to implement this new configuration, the physician operating the ultrasound probe must not stay in the radiotherapy room. This motivates the development of a physician‐commanded robotic manipulation system for target localization in conformal radiotherapy. The proposed robotic control system is in eye‐to‐hand configuration with binocular vision and force sensing. The ultrasound probe mounted on the end‐effector of the manipulator is controlled to follow the pose commanded by the physician. Based on the measurements from a six‐axis force sensor, the probe can be controlled further to maintain the desired contact force against the possibly‐deforming treatment surface. The proposed hybrid force and vision‐based control approach has been validated by experimenting with a six‐degrees‐of‐freedom industrial manipulator to allow clear ultrasound images.
iOD907, the first genome‐scale metabolic model for the milk yeast Kluyveromyces lactis
Authors: Dias Oscar , Pereira Rui , Gombert Andreas K. , Ferreira Eugénio C. , Rocha Isabel 
Published: April 2014

AbstractWe describe here the first genome‐scale metabolic model of Kluyveromyces lactis, iOD907. It is partially compartmentalized (four compartments), composed of 1867 reactions and 1476 metabolites. The iOD907 model performed well when comparing the positive growth of K. lactis to Biolog experiments and to an online catalogue of strains that provides information on carbon sources in which K. lactis is able to grow. Chemostat experiments were used to adjust non‐growth‐associated energy requirements, and the model proved accurate when predicting the biomass, oxygen and carbon dioxide yields. When compared to published experiments, in silico knockouts accurately predicted in vivo phenotypes. The iOD907 genome‐scale metabolic model complies with the MIRIAM (minimum information required for the annotation of biochemical models) standards for the annotation of enzymes, transporters, metabolites and reactions. Moreover, it contains direct links to Kyoto encyclopedia of genes and genomes (KEGG; for enzymes, metabolites and reactions) and to the Transporters Classification Database (TCDB) for transporters, allowing easy comparisons to other models. Furthermore, this model is provided in the well‐established systems biology markup language (SBML) format, which means that it can be used in most metabolic engineering platforms, such as OptFlux or Cobra. The model is able to predict the behavior of K. lactis under different environmental conditions and genetic perturbations. Furthermore, by performing simulations and optimizations, it can be important in the design of minimal media and will allow insights on the milk yeast's metabolism, as well as identifying metabolic engineering targets for improving the production of products of interest.
Comparison of energy metabolism in liver grafts from donors after circulatory death and donors after brain death during cold storage and reperfusion
Authors: Perera M T P R , Richards D A , Silva M A , Ahmed N , Neil D A , Murphy N , Mirza D F 
Published: April 2014

AbstractBackgroundDonation after circulatory death (DCD) liver grafts have supplemented the donor organ pool, but certain adverse outcomes have prevented exploration of the full potential of such organs. The aim of this study was to determine key differences in basic energy metabolism between DCD and donation after brainstem death (DBD) grafts.MethodsMicrodialysis samples from DCD and DBD allograft parenchyma from cold storage to 48 h after reperfusion were analysed by colorimetric methods. Interstitial lactate, pyruvate and glycerol levels were measured and the lactate/pyruvate ratio was calculated to estimate energy depletion of the grafts. Histological features of ischaemia and reperfusion injury were assessed.ResultsDonor age, extent of steatosis and cold ischaemia time were comparable between ten DCD and 20 DBD organs. DCD grafts had higher levels of interstitial lactate (median 11·6 versus 1·2 mmol/l; P = 0·015) and increased lactate/pyruvate ratio (792 versus 38; P = 0·001) during cold storage. There was no significant difference in glycerol levels between DCD and DBD grafts (225·1 versus 127·5 µmol/l respectively; P = 0·700). Rapid restoration of energy levels with lactate clearance, increased pyruvate levels and reduced lactate/pyruvate ratio was seen following reperfusion of functioning DCD grafts, parallel with levels in DBD grafts. Histology revealed more pronounced glycogen depletion in DCD grafts. Three allografts that failed owing to primary non-function showed energy exhaustion with severe glycogen depletion.ConclusionLiver grafts from DCD donors exhibited depletion of intracellular energy reserves during cold storage. Failed allografts showed severe energy depletion. Modified organ preservation techniques to minimize organ injury related to altered energy metabolism may enable better utilization of donor organs after circulatory death.