bluuebunny/crossref_metadata_2025_split huggingface dataset:
Crystal structures of two tetrameric β‐carbonic anhydrases from the filamentous ascomycete Sordaria macrospora
Authors: Lehneck Ronny , Neumann Piotr , Vullo Daniela , Elleuche Skander , Supuran Claudiu T. , Ficner Ralf , Pöggeler Stefanie 
Published: February 2014

Carbonic anhydrases (CAs) are metalloenzymes catalyzing the reversible hydration of carbon dioxide to bicarbonate (hydrogen carbonate) and protons. CAs have been identified in archaea, bacteria and eukaryotes and can be classified into five groups (α, β, γ, δ, ζ) that are unrelated in sequence and structure. The fungal β‐class has only recently attracted attention. In the present study, we investigated the structure and function of the plant‐like β‐CA proteins CAS1 and CAS2 from the filamentous ascomycete Sordaria macrospora. We demonstrated that both proteins can substitute for the Saccharomyces cerevisiae β‐CA Nce103 and exhibit an in vitro CO2 hydration activity (kcat/Km of CAS1: 1.30 × 106 m−1·s−1; CAS2: 1.21 × 106 m−1·s−1). To further investigate the structural properties of CAS1 and CAS2, we determined their crystal structures to a resolution of 2.7 Å and 1.8 Å, respectively. The oligomeric state of both proteins is tetrameric. With the exception of the active site composition, no further major differences have been found. In both enzymes, the Zn2+ ‐ion is tetrahedrally coordinated; in CAS1 by Cys45, His101 and Cys104 and a water molecule and in CAS2 by the side chains of four residues (Cys56, His112, Cys115 and Asp58). Both CAs are only weakly inhibited by anions, making them good candidates for industrial applications.Structured digital abstract
CAS1 and CAS2 bind by x-ray crystallography (View interaction)
DatabaseStructural data have been deposited in the Protein Data Bank database under accession numbers 4O1J for CAS1 and 4O1K for CAS2.
Soil nutrient budgets following projected corn stover harvest for biofuel production in the conterminous United States
Authors: Tan Zhengxi , Liu Shuguang 
Published: February 2014

AbstractIncreasing demand for food and biofuel feedstocks may substantially affect soil nutrient budgets, especially in the United States where there is great potential for corn (Zea mays L) stover as a biofuel feedstock. This study was designed to evaluate impacts of projected stover harvest scenarios on budgets of soil nitrogen (N), phosphorus (P), and potassium (K) currently and in the future across the conterminous United States. The required and removed N, P, and K amounts under each scenario were estimated on the basis of both their average contents in grain and stover and from an empirical model. Our analyses indicate a small depletion of soil N (−4 ± 35 kg ha−1) and K (−6 ± 36 kg ha−1) and a moderate surplus of P (37 ± 21 kg ha−1) currently on the national average, but with a noticeable variation from state to state. After harvesting both grain and projected stover, the deficits of soil N, P, and K were estimated at 114–127, 26–27, and 36–53 kg ha−1 yr−1, respectively, in 2006–2010; 131–173, 29–32, and 41–96 kg ha−1 yr−1, respectively, in 2020; and 161–207, 35–39, and 51–111 kg ha−1 yr−1, respectively, in 2050. This study indicates that the harvestable stover amount derived from the minimum stover requirement for maintaining soil organic carbon level scenarios under current fertilization rates can be sustainable for soil nutrient supply and corn production at present, but the deficit of P and K at the national scale would become larger in the future.
Comparative Analysis of Low‐Cycle Fatigue Behavior of 2D‐Cf‐PyC/SiC Composites in Different Environments
Authors: Zhang Yani , Cheng Laifei , Zhang Litong , Luan Xingang 
Published: February 2014

A carbon fiber‐reinforced silicon carbide matrix composite with pyrolytic carbon interface (Cf‐PyC/SiC) and a protective coating was prepared by isothermal low pressure chemical vapor infiltration. Low‐cycle fatigue behavior of this material system was investigated at high temperatures up to 1800°C in a combustion environment and at room temperature in air, respectively. The combustion environment includes thermal mechanical loading, high temperatures, and oxidizing atmosphere. Low‐cycle fatigue tests were conducted at a maximum stress level of 180 MPa but at various temperatures and fatigue cycles. The residual strength variation of fatigue‐survived samples was due to different damage mechanisms in different environments.
Population genomics of eusocial insects: the costs of a vertebrate‐like effective population size
Authors: Romiguier J. , Lourenco J. , Gayral P. , Faivre N. , Weinert L. A. , Ravel S. , Ballenghien M. , Cahais V. , Bernard A. , Loire E. , Keller L. , Galtier N. 
Published: February 2014

AbstractThe evolution of reproductive division of labour and social life in social insects has lead to the emergence of several life‐history traits and adaptations typical of larger organisms: social insect colonies can reach masses of several kilograms, they start reproducing only when they are several years old, and can live for decades. These features and the monopolization of reproduction by only one or few individuals in a colony should affect molecular evolution by reducing the effective population size. We tested this prediction by analysing genome‐wide patterns of coding sequence polymorphism and divergence in eusocial vs. noneusocial insects based on newly generated RNA‐seq data. We report very low amounts of genetic polymorphism and an elevated ratio of nonsynonymous to synonymous changes – a marker of the effective population size – in four distinct species of eusocial insects, which were more similar to vertebrates than to solitary insects regarding molecular evolutionary processes. Moreover, the ratio of nonsynonymous to synonymous substitutions was positively correlated with the level of social complexity across ant species. These results are fully consistent with the hypothesis of a reduced effective population size and an increased genetic load in eusocial insects, indicating that the evolution of social life has important consequences at both the genomic and population levels.
Comparing omeprazole with fluoxetine for treatment of patients with heartburn and normal endoscopy who failed once daily proton pump inhibitors: Double‐blind placebo‐controlled trial
Authors: Ostovaneh M. R. , Saeidi B. , Hajifathalian K. , Farrokhi‐Khajeh‐Pasha Y. , Fotouhi A. , Mirbagheri S. S. , Emami H. , Barzin G. , Mirbagheri S. A. 
Published: February 2014

AbstractBackgroundPatients with heartburn but without esophageal erosion respond less well to proton pump inhibitors (PPIs). There is a growing body of evidence implicating the role of psychological comorbidities in producing reflux symptoms. Pain modulators improve symptoms in patients with other functional gastrointestinal disorders. We aimed to compare the efficacy of fluoxetine with omeprazole and placebo to achieve symptomatic relief in patients with heartburn and normal endoscopy who failed once daily PPIs.MethodsEndoscopy‐negative patients with heartburn who failed once daily PPIs were randomly allocated to receive 6 weeks treatment of fluoxetine, omeprazole, or placebo. Random allocation was stratified according to ambulatory pH monitoring study. Percentage of heartburn‐free days and symptom severity was assessed.Key ResultsSixty patients with abnormal and 84 patients with normal pH test were randomized. Subjects receiving fluoxetine experienced more improvement in percentage of heartburn‐free days (median 35.7, IQR 21.4–57.1) than those on omeprazole (median 7.14, IQR 0–50, p < 0.001) or placebo (median 7.14, IQR 0–33.6, p < 0.001). In normal pH subgroup, fluoxetine was superior to both omeprazole and placebo regarding percentage of heartburn‐free days (median improvement, 57.1, IQR 35.7–57.1 vs 13.9, IQR, 0–45.6 and 7.14, 0–23.8, respectively, p < 0.001), but no significant difference was observed between medications in abnormal pH subgroup.Conclusions & InferencesFluoxetine was superior to omeprazole for improving the symptoms of patients with heartburn and normal endoscopy who failed once daily PPIs. The superiority of fluoxetine was mostly attributed to those with normal esophageal pH rather than those with abnormal pH (ClinicalTrials.gov, number NCT01269788).
Expansion of banana (Musa acuminata) gene families involved in ethylene biosynthesis and signalling after lineage‐specific whole‐genome duplications
Authors: Jourda Cyril , Cardi Céline , Mbéguié‐A‐Mbéguié Didier , Bocs Stéphanie , Garsmeur Olivier , D'Hont Angélique , Yahiaoui Nabila 
Published: February 2014

Summary

Whole‐genome duplications (WGDs) are widespread in plants, and three lineage‐specific WGDs occurred in the banana (Musa acuminata) genome. Here, we analysed the impact of WGDs on the evolution of banana gene families involved in ethylene biosynthesis and signalling, a key pathway for banana fruit ripening.

Banana ethylene pathway genes were identified using comparative genomics approaches and their duplication modes and expression profiles were analysed.

Seven out of 10 banana ethylene gene families evolved through WGD and four of them (1‐aminocyclopropane‐1‐carboxylate synthase (ACS), ethylene‐insensitive 3‐like (EIL), ethylene‐insensitive 3‐binding F‐box (EBF) and ethylene response factor (ERF)) were preferentially retained. Banana orthologues of AtEIN3 and AtEIL1, two major genes for ethylene signalling in Arabidopsis, were particularly expanded. This expansion was paralleled by that of EBF genes which are responsible for control of EIL protein levels. Gene expression profiles in banana fruits suggested functional redundancy for several MaEBF and MaEIL genes derived from WGD and subfunctionalization for some of them.

We propose that EIL and EBF genes were co‐retained after WGD in banana to maintain balanced control of EIL protein levels and thus avoid detrimental effects of constitutive ethylene signalling. In the course of evolution, subfunctionalization was favoured to promote finer control of ethylene signalling.
Hematopoietic stem cell transplantation effects on spinal cord compression in Hurler
Authors: Ferrara Giovanna , Maximova Natalia , Zennaro Floriana , Gregori Massimo , Tamaro Paolo 
Published: February 2014

AbstractHurler syndrome type 1 (MPS‐1) is an autosomal recessive lysosomal disorder due to the deficiency of the enzyme alpha‐L‐iduronidase which is necessary for the degradation of dermatan and heparan sulfate. It is characterized by deposit of glycosaminoglycans in tissues, progressive multisystem dysfunction, and early death. HSCT for children with MPS‐I is effective, resulting in increased life expectancy and improvement of clinical parameters. The spinal MRI performed on a female 10 yr old undergoing HSCT at the age of 18 months and receiving ERT revealed a considerable decrease in soft tissue around the tip of odontoid causing a significant reduction in spinal cord compression. In light of this result, we suppose that combined ERT and HSCT are successful in Hurler I disease.
Signaling by small metabolites in systemic acquired resistance
Authors: Shah Jyoti , Chaturvedi Ratnesh , Chowdhury Zulkarnain , Venables Barney , Petros Robby A. 
Published: February 2014

SummaryPlants can retain the memory of a prior encounter with a pest. This memory confers upon a plant the ability to subsequently activate defenses more robustly when challenged by a pest. In plants that have retained the memory of a prior, localized, foliar infection by a pathogen, the pathogen‐free distal organs develop immunity against subsequent infections by a broad‐spectrum of pathogens. The long‐term immunity conferred by this mechanism, which is termed systemic acquired resistance (SAR), is inheritable over a few generations. Signaling mediated by the phenolic metabolite salicylic acid (SA) is critical for the manifestation of SAR. Recent studies have described the involvement of additional small metabolites in SAR signaling, including methyl salicylate, the abietane diterpenoid dehydroabietinal, the lysine catabolite pipecolic acid, a glycerol‐3‐phosphate‐dependent factor and the dicarboxylic acid azelaic acid. Many of these metabolites can be systemically transported through the plant and probably facilitate communication by the primary infected tissue with the distal tissues, which is essential for the activation of SAR. Some of these metabolites have been implicated in the SAR‐associated rapid activation of defenses in response to subsequent exposure to the pathogen, a mechanism termed priming. Here, we summarize the role of these signaling metabolites in SAR, and the relationship between them and SA signaling in SAR.
Behavior of the Spent Fuel Pool and Dose Rate Calculations for the CPR1000 Reactor Under Severe Accident Conditions Using the Integral Code MELCOR
Authors: Mueller Klaus , Yeung Moses , Byard Justin , Peng Zhen Xun , Tao Jun , Liao Yehong , Duan Cheng Jie , Yang Zhi Fei , Xie Xiao Fei 
Published: February 2014

The behavior of the spent fuel pool and the fission product release and transport for the CPR1000 reactor under severe accident conditions was analyzed using the integral severe accident code MELCOR. In the investigated accident scenario a total failure of the pump of the spent fuel cooling system was assumed. Furthermore, it is assumed that accident management fails to bring water into the spent fuel pool using mobile pumps or due to the non-recovery of the cooling pump. The grace time available for measures in order to avoid significant fission product release to the environment is determined. The calculated hydrogen mass flow rate due to clad oxidation and the steam flow rate from the spent fuel pool to the compartment above the spent fuel pool serve as boundary conditions for the three dimensional fluid dynamics code GASFLOW to assess possible hydrogen combustion or detonation in the compartment. Using this spent fuel pool MELCOR model the dose submerged in air or water can be determined.
The calculated gamma dose rate in a specific compartment can be used for equipment qualification and compartment accessibility assessment. It was found that after four days the fuel assemblies are significantly heated-up and ten hours later the fission products are released as well as a significant amount of hydrogen is produced. A preliminary GASFLOW analysis shows by assuming an air atmosphere in the fuel building, that the risk of a hydrogen combustion or detonation is high. In late state of the accident a convection flow of pure hydrogen is established in spent fuel pool region. It was shown, that the flow conditions strongly influence the fission product transport behavior and consequently the dose rates in the compartment above the spent fuel pool.
Evaluation of Interaction Effects on Part-Through Cracks in Steam Generator Tubes
Authors: Kang Yong-Seok , Kim Hong-Deok , Lee Kuk-Hee , Park Jai-Hak 
Published: February 2014

Degraded steam generator tubing can affect its safety functions. Therefore, its integrity should be maintained for each degradation form and all detected degradation must be assessed to verify that if adequate integrity is retained. Determination of tube integrity limits includes identifying acceptable structural parameters such as flaw length, depth, and amplitude of signals. If we consider just single-cracked tubes, short and deep flaws are not likely to threaten structural integrity of tubes. But if it has multiple-cracks, we have to consider interaction effects of multiple adjacent cracks on its burst pressure. Because adjacent multiple cracks can be merged due to the crack growth then it can challenge against the structural performance limit. There are some studies on the interaction effects of adjacent cracks. However, existing works on the interaction effect consider only through-wall cracks. No study has been carried out on the interaction effects of part-through cracks. Most cracks existing in real steam generator tubing are not through-wall cracks but part-through cracks. Hence, integrity of part-through cracks is more practical issue than that of through-wall cracks.
This paper presents experimental burst test results with steam generator tubing for evaluation of interaction effects with axial oriented two collinear and parallel part-through cracks. The interaction effect between two adjacent cracks disappeared when the distance exceeds about 2 mm.
Extension of Load Follow Operation of PWRs Without Boron Adjustment
Authors: Wang Li , Liu Yang , Tai Yun , Zhang Yawei , Tang Zhenpeng 
Published: February 2014

Due to development of electric power system, the proportion of nuclear power and its needs for Load follow operation have become large. Then there would be higher requirements to the power control ability of the nuclear power system.
The project with China’s own brands and using the advanced pressurized water reactor (APWR) nuclear power technology, CPR1000, adopts a control method called Mode G, using G banks, N banks, R bank and soluble boron to perform the load follow control. The common Point Model, widely used in conventional core modeling, cannot successfully research the axial power distribution. But in this paper, a two-node dynamic function model was built, taking CPR1000 as an example, considering the coupling coefficient and mutual influence. The transient parameter values were obtained by the steady-state calculation of single channel with its original structure parameter and operation parameter. Then the core system simulation of CPR1000 was modeled. In order to carry out the load follow operation without the boron adjustment, known as BTP mode, the control banks were regrouped to control the average temperature by M banks and axial offset by AO bank. The last, the optimal control implementation was connected to the core simulation platform to operate with the variable daily load. The feasibility and effectiveness of the control policy and the simulation system are validated by the calculation results via one-dimensional in axial computer code APOC.
Results of computations performed for a reference reactor were present, giving the possibility that the optimal control policy could stretches the capability of the reactor to follow an average daily load curve. The paper demonstrated in principle that the BTP mode was feasible for CPR1000.
Development of Numerical Simulation for Jet Breakup Behavior in Complicated Structure of BWR Lower Plenum: 1 — Preliminary Analysis of Jet Breakup Behavior in Complicated Structure by TPFIT
Authors: Suzuki Takayuki , Yoshida Hiroyuki , Nagase Fumihisa , Abe Yutaka , Kaneko Akiko 
Published: February 2014

In order to improve the safety of Boiling Water Reactor (BWR), it is required to know the behavior of the plant when an accident occurred as can be seen at Fukushima Daiichi nuclear power plant accident. Especially, it is important to estimate the behavior of molten core jet in the lower part of the containment vessel at severe accident.
In the BWR lower plenum, the flow characteristics of molten core jet are affected by many complicated structures, such as control rod guide tubes, instrument guide tubes and core support plate. However, it is difficult to evaluate these effects on molten core jet experimentally. Therefore, we considered that multi-phase computational fluid dynamics approach is the best way to estimate the effects on molten core jet by complicated structure.
The objective of this study is to develop the evaluation method for the flow characteristic of molten core jet including the effects of the complicated structures in the lower plenum. So we are developing a simulation method to estimate the behavior of molten core jet falling down through the core support plate to the lower plenum of the BWR. The method has been developed based on interface tracking method code TPFIT (Two Phase Flow simulation code with Interface Tracking). To verify and validate the applicability of the developed method in detail, it is necessary to obtain the experimental data that can be compared with detailed numerical results by the TPFIT. Thus, in this study, we are carrying out experimental works by use of multi-phase flow visualization technique. In the experiments, time series of interface shapes are observed by high speed camera and velocity profiles in/out of the jet will be measured by the PIV method.
In this paper, the outline of the developing method based on the TPFIT was explained. And, the developing method was applied to preliminary experiment with/without modeled complicated structures. As the results, predicted interface shapes were almost agreed with measured data. However, predicted falling down velocity of the jet was lower than measured data. We considered causes of this underestimation and improved the method and simulation conditions to resolve this problem.
Numerical Investigation of Flow and Heat Transfer Characteristics in Wire-Wrap Tight Lattice 19-Rod Bundle
Authors: Li Minggang , Wang Jun , Nie Changhua , Yan Xiao , Huang Yanping , Yang Zumao , Xie Feng 
Published: February 2014

Flow and heat transfer characteristics in wire-wrap tight lattice rod bundle have been investigated through CFD code ANSYS CFX 13.0. The bundle consists of 19 fuel rods with triangular tight lattice configuration. The rod ratio of rod pitch to rod diameter is 1.167. Four wires with a diameter of 0.5 mm are helically wrapped on the surface of each fuel rod. The ratio of wire-wrap helical pitch to the rod diameter is varied from 27.5 to 52.5.
Through simulating wire-wrap 3-rod bundle with tetrahedron and hexahedron grid systems, the grid system which applies to simulating the wire-wrap tight lattice rod bundle has been obtained.
The predicted results of eddy viscosity based turbulence models (k–ε, SST) and Reynolds stress turbulence models (BSL, SSG) are compared with each other and several experimental correlations for friction factor and Nusselt number. The predicted results of all the turbulence models are almost the same in some respects, but the friction factor predicted by the eddy viscosity models is higher than that predicted by the RSM.
The effect of wire-wrap on pressure drop, friction factor, secondary flow, heat transfer, velocity distribution and temperature distribution in different subchannels (interior, edge and corner) has been analyzed by comparing with those of the bare rod bundle. The effect of wire-wrap pitch on the flow and heat transfer characteristics has also been studied.
Modelling of QUENCH 03 and QUENCH 06 Experiments Using RELAP/SCDAPSIM Code
Authors: Kaliatka Tadas , Ušpuras Eugenijus , Kaliatka Algirdas 
Published: February 2014

An important accident management measure for controlling severe accident transients in Light Water Reactors is the injection of water to cool the degrading core. Flooding of the overheated core, which causes quenching of the fuel rods, is considered a worst-case scenario regarding hydrogen generation rates which should not exceed safety-relevant critical values.
Within the frame of the QUENCH test-program the loss of coolant accidents with the following flooding of overheated core in Light Water Reactors is analysed using an experimental facility. The modelling of QUENCH-03 and QUENCH-06 experiments was performed with RELAP/SCDAPSIM computer code. The observed calculation results showed that thermal properties of shroud materials (heat losses through the shroud) and electrical power of fuel simulators are the main source of uncertainty in the calculations.
The main idea of this article is modification of input parameters to receive the best agreement with the measurements for the selected QUENCH test. Modified input parameters are used in the input deck for another QUENCH test. The good agreement between calculation results and measurements of both QUENCH tests demonstrated the correctness of modified parameters and legitimacy with the real physical processes.