bluuebunny/crossref_metadata_2025_split huggingface dataset:
Two Completely Different Mechanisms for Highly Specific Na+ Recognition by DNAzymes
Authors: Zhou Wenhu , Saran Runjhun , Ding Jinsong , Liu Juewen 
Published: June 2017

AbstractOur view of the interaction between Na+ and nucleic acids was changed by a few recently discovered Na+‐specific RNA‐cleaving DNAzymes. In addition to nonspecific electrostatic interactions, highly specific recognition is also possible. Herein, two such DNAzymes, named EtNa and Ce13d, are compared to elucidate their mechanisms of Na+ binding. Mutation studies indicate that they have different sequence requirements. Phosphorothioate (PS) substitution at the scissile phosphate drops the activity of EtNa 140‐fold, and it cannot be rescued by thiophilic Cd2+ or Mn2+, whereas the activity of PS‐modified Ce13d can be rescued. Na+‐dependent activity assays indicate that two Na+ ions bind cooperatively in EtNa, and each Na+ likely interacts with a nonbridging oxygen atom in the scissile phosphate, whereas Ce13d binds only one Na+ ion in a well‐defined Na+ aptamer, and this Na+ ion does not directly interact with the scissile phosphate. Both DNAzymes display a normal pH–rate profile, with a single deprotonation reaction required for catalysis. For EtNa, Na+ fails to protect the conserved nucleotides from dimethyl sulfate attack, and no specific Na+ binding is detected by 2‐aminopurine fluorescence, both of which are different from those observed for Ce13d. This work suggests that EtNa binds Na+ mainly through its scissile phosphate without significant involvement of the nucleotides in the enzyme strand, whereas Ce13d has a well‐defined aptamer for Na+ binding. Therefore, DNA has at least two distinct ways to achieve highly selective Na+ binding.
The Exfoliation of Graphite Particles in the Vibratory Disk Mill
Authors: Aman Sergej , Aman Alexander , Hintz Werner , Trüe Michael , Veit Peter , Hirsch Sören 
Published: June 2017

AbstractThe exfoliation of graphite particles during the treatment in the vibratory disk mill containing commercial sugar was investigated. During the collision of the grinding ring with the grinding chamber wall an intensive stressing of graphite takes place. After treatment in the mill, the resulting dark paste was solved in water and subjected to 10 min sonication. The suspension was centrifuged to remove the not exfoliated multilayered particles. Analysis of Raman spectra shows the presence of graphite sheets in suspension. The represented method of exfoliation is environmentally friendly and scalable.
Improving color reproduction accuracy of an OLED‐based mobile display
Authors: Kirchner Eric , van der Lans Ivo , Perales Esther , Martínez‐Verdú Francisco 
Published: June 2017

AbstractFor improving color reproduction accuracy of mobile displays, we recently developed a generic model for device‐specific display characterization model that also accounts for the influence of illuminance from ambient light. In the present article, this MDCIM model (Mobile Display Characterization and Illumination Model) is applied to a Samsung Galaxy S4 display, representing OLED displays. The performance of the model was tested by determining the values of all model parameters using publicly available technical data only. We organized visual tests under various ambient illuminance levels from 600 to 3000 lux. Seven observers compared the color of displayed images with the color of physical samples. With the MDCIM method, the quality of the color match was shown to improve considerably as compared to using only device‐independent encoding color space. On a five‐point scale to quantify color reproduction accuracy, the MDCIM resulted in more than 1 unit improvement at 1000 lux illuminance. At lower and higher illuminance, the improvement was even larger. Color reproduction accuracy was found to be at least reasonable, according to the subjective assessment of visual observers, for more than 75% of the samples when using the MDCIM method, but only 20% or less when using the common device‐independent encoding color space.
Attribute‐based access control management for multicloud collaboration
Authors: John John C. , Sural Shamik , Gupta Arobinda 
Published: June 2017

SummarySecurity of applications has been identified as one of the major concerns in today's multicloud collaborative environment. These applications are often bounded by the constraints of the disparate cloud domains they are deployed in. A fine‐grained access control mechanism such as attribute‐based access control (ABAC) is considered to be an appropriate choice for authorization management in this context. However, identifying a suitable set of ABAC rules, often called rule mining, is a critical step in building ABAC‐based systems. We propose 2 approaches for intercloud rule formation in ABAC. In the first approach, we consider cross domain rule mining as the problem of forming a minimal set of positive authorizations only. The second approach shows the advantage of developing deny rules along with positive authorizations in reducing the total number of rules, and hence, the response time for evaluating access requests. The problem is proved to be NP‐hard. Heuristic solutions are proposed and evaluated on benchmark datasets showing encouraging results.
Kinetics of CO2 Hydrogenation to Hydrocarbons over Iron–Silica Catalysts
Authors: Owen Rhodri E. , Mattia Davide , Plucinski Pawel , Jones Matthew D. 
Published: June 2017

AbstractThe conversion of CO2 to hydrocarbons is increasingly seen as a potential alternative source of fuel and chemicals, while at the same time contributing to addressing global warming effects. An understanding of kinetics and mass transfer limitations is vital to both optimise catalyst performance and to scale up the whole process. In this work we report on a systematic investigation of the influence of the different process parameters, including pore size, catalyst support particle diameter, reaction temperature, pressure and reactant flow rate on conversion and selectivity of iron nanoparticle ‐silica catalysts. The results provided on activation energy and mass transfer limitations represent the basis to fully design a reactor system for the effective catalytic conversion of CO2 to hydrocarbons.
Joint genotype‐ and ancestry‐based genome‐wide association studies in admixed populations
Authors: Szulc Piotr , Bogdan Malgorzata , Frommlet Florian , Tang Hua 
Published: June 2017

ABSTRACTIn genome‐wide association studies (GWAS) genetic loci that influence complex traits are localized by inspecting associations between genotypes of genetic markers and the values of the trait of interest. On the other hand, admixture mapping, which is performed in case of populations consisting of a recent mix of two ancestral groups, relies on the ancestry information at each locus (locus‐specific ancestry). Recently it has been proposed to jointly model genotype and locus‐specific ancestry within the framework of single marker tests. Here, we extend this approach for population‐based GWAS in the direction of multimarker models. A modified version of the Bayesian information criterion is developed for building a multilocus model that accounts for the differential correlation structure due to linkage disequilibrium (LD) and admixture LD. Simulation studies and a real data example illustrate the advantages of this new approach compared to single‐marker analysis or modern model selection strategies based on separately analyzing genotype and ancestry data, as well as to single‐marker analysis combining genotypic and ancestry information. Depending on the signal strength, our procedure automatically chooses whether genotypic or locus‐specific ancestry markers are added to the model. This results in a good compromise between the power to detect causal mutations and the precision of their localization. The proposed method has been implemented in R and is available athttp://www.math.uni.wroc.pl/~mbogdan/admixtures/.
Effect of tetramethylpyrazine (TMP) on Ca2+ signal transduction and cell viability in a model of renal tubular cells
Authors: Fang Yi‐Chien , Chou Chiang‐Ting , Liang Wei‐Zhe , Kuo Chun‐Chi , Hsu Shu‐Shong , Wang Jue‐Long , Jan Chung‐Ren 
Published: June 2017

AbstractTetramethylpyrazine (TMP) is a compound purified from herb. Its effect on Ca2+ concentrations ([Ca2+]i) in renal cells is unclear. This study examined whether TMP altered Ca2+ signaling in Madin‐Darby canine kidney (MDCK) cells. TMP at 100–800 μM induced [Ca2+]i rises, which were reduced by Ca2+ removal. TMP induced Mn2+ influx implicating Ca2+ entry. TMP‐induced Ca2+ entry was inhibited by 30% by modulators of protein kinase C (PKC) and store‐operated Ca2+ channels. Treatment with the endoplasmic reticulum Ca2+ pump inhibitor 2,5‐di‐tert‐butylhydroquinone (BHQ) inhibited 93% of TMP‐evoked [Ca2+]i rises. Treatment with TMP abolished BHQ‐evoked [Ca2+]i rises. Inhibition of phospholipase C (PLC) abolished TMP‐induced responses. TMP at 200–1000 μM decreased viability, which was not reversed by pretreatment with the Ca2+ chelator 1,2‐bis(2‐aminophenoxy)ethane‐N,N,N′,N′‐tetraacetic acid‐acetoxymethyl ester. Together, in MDCK cells, TMP induced [Ca2+]i rises by evoking PLC‐dependent Ca2+ release from endoplasmic reticulum and Ca2+ entry via PKC‐sensitive store‐operated Ca2+ entry. TMP also caused Ca2+‐independent cell death.
Lysophosphatidic acid‐triggered pathways promote the acquisition of trophoblast endovascular phenotype in vitro
Authors: Beltrame Jimena S. , Sordelli Micaela S. , Cañumil Vanesa A. , Franchi Ana M. , Ribeiro María L. 
Published: June 2017

AbstractSuccessful implantation and placentation requires that extravillous cytotrophoblast acquires an endovascular phenotype and remodels uterine spiral arteries. Defects in this mechanism correlate with severe obstetric complications as implantation failure and preeclampsia. Lysophosphatidic acid (LPA) participates in embryo implantation and contributes to vascular physiology in different biological systems. However, the role of LPA on trophoblast endovascular transformation has not been studied. Due to difficulties in studying human pregnancy in vivo, we adopted a pharmacological approach in vitro to investigate LPA action in various aspects of trophoblast endovascular response, such as the formation of endothelial capillary‐like structures, migration, and proliferation. The HTR‐8/SVneo cell line established from human first trimester cytotrophoblast was used to model the acquisition of the endovascular phenotype by the invading trophoblast. LPA increased HTR‐8/SVneo tube formation, migration (wound healing assay and phalloidin staining) and proliferation (MTT assay). LPA G protein‐coupled receptors, LPA1 and LPA3, were expressed in HTR‐8/SVneo. By using selective antagonists, we showed that enhanced tubulogenesis was mediated by LPA3. In addition, cyclooxygenase‐2 and inducible nitric oxide synthase pathways participated in LPA‐stimulated tubulogenesis. Inducible nitric oxide synthase was activated downstream cyclooxygenase‐2. Furthermore, prostaglandin E2 and a nitric oxide donor (SNAP) increased trophoblast tube formation in a concentration‐dependent manner. Finally, we observed that cyclooxygenase‐2 and inducible nitric oxide synthase were localized in the nucleus, and LPA did not modify their cellular distribution. Our results show that LPA‐triggered regulatory pathways promote trophoblast endovascular response in vitro, suggesting a new role for LPA during spiral artery remodeling at the maternal‐fetal interface.
Genetic variants in 3′‐UTRs of MTHFR in the pregnancies complicated with preeclampsia and bioinformatics analysis
Authors: Mohammadpour‐Gharehbagh Abbas , Salimi Saeedeh , Keshavarzi Farshid , Saeidian Foozieh , Mousavi Mahdieh , Teimoori Batool , Esmaeilipour Maryam , Mokhtari Mojgan 
Published: June 2017

AbstractPreeclampsia (PE) as a pregnancy‐specific disorder is the major cause of mortality and morbidity of mothers and fetuses. This study attempts to investigate the possible association between the 2572C>A (rs4846049) and 4869C>G (rs1537514) polymorphisms in the 3′‐ untranslated region of MTHFR gene and the risk of PE. A total of 198 patients diagnosed with PE and 171 unrelated, age matched healthy pregnant women, were recruited for this case‐control study. The MTHFR 2572C>A and 4869C>G genotyping was performed by the polymerase chain reaction‐restriction fragment length polymorphism (PCR‐RFLP) method. The CG genotype of MTHFR 4869C>G was associated with decreased risk of PE, and this genotype was found to be a protective factor for PE susceptibility. There was no significant difference in the genotypes of MTHFR 2572C>A polymorphism between PE patients and control group. The frequency of combined AC/CG genotypes of MTHFR 2572C>A and 4869C>G polymorphisms were less frequent in PE patients and were associated with a lower risk of PE. The C‐G and A‐G haplotypes of MTHFR 2572C>A and 4869C>G polymorphisms were significantly lower in PE patients. In conclusion, the CG genotype of MTHFR 4869C>G polymorphism was associated with a lower risk of PE. No association was found between MTHFR 2572C>A polymorphism and PE.
The effects of chronic smoking on total cerebral blood volume measured by carotid and vertebral artery doppler ultrasonography
Authors: Kalfaoglu Melike E. , Hızal Mustafa , Kiyan Aysu , Gurel Kamil 
Published: June 2017

ABSTRACTPurposeTo evaluate the effects of chronic cigarette smoking on total cerebral blood flow in healthy adults by Doppler ultrasonography (US).MethodsWe evaluated 50 smoker (median age 29) and 50 nonsmoker (median age 28) healthy, 20‐ to 40‐year‐old subjects without any cardiovascular and cerebrovascular disease. Peak systolic maximal blood flow velocity (PSV), end‐diastolic maximal blood flow velocity (EDV), time‐averaged mean blood flow velocity (TAMV), resistance index (RI), and pulsatility index (PI) were measured in the left and right carotid and vertebral arteries, and total cerebral blood flow volume was calculated.ResultsThere was no significant difference of smoking rate between genders. Blood pressure and PSV values were similar in both groups. EDV values of internal carotid artery (ICA) and vertebral artery (VA) were lower and RI and PI values were higher in smokers. TAMV, total ICA (−10.8%) and VA (−6%) flow volume, and tCBF (−9.2%) were lower in smokers.ConclusionsDoppler US is an effective tool to detect tCBF volume decrease in chronic cigarette smokers. Although minimal, this decrease, as demonstrated here in asymptomatic, healthy people, might be critical in patients with subclinical cerebral arterial insufficiency. © 2017 Wiley Periodicals, Inc. J Clin Ultrasound 45:561–565, 2017
An unusual cause of chest pain: An isolated huge cardiac hydatid cyst
Authors: Uygur Begum , Ustabasioglu Fethi Emre , Karakurt Huseyin , Akinci Okan , Celik Omer 
Published: June 2017

ABSTRACTHydatid disease is a human parasitic infection caused by the larval stage of Echinococcus granulosus. The most common locations for hydatid cysts are the liver and lungs. Cardiac involvement is rare, and isolated cardiac hydatid cysts are even more unusual. We report the case a 48‐year‐old female patient with an isolated huge cardiac hydatid cyst involving both the left ventricular free wall and the pericardium, and presenting with atypical chest pain. © 2017 Wiley Periodicals, Inc. J Clin Ultrasound 46:262–264, 2018
Dynamic choosability of triangle‐free graphs and sparse random graphs
Authors: Kim Jaehoon , Ok Seongmin 
Published: June 2017

AbstractTher‐dynamic choosability of a graph G, written , is the least k such that whenever each vertex is assigned a list of at least k colors a proper coloring can be chosen from the lists so that every vertex v has at least neighbors of distinct colors. Let ch(G) denote the choice number of G. In this article, we prove when is bounded. We also show that there exists a constant C such that the random graph with almost surely satisfies . Also if G is a triangle‐free regular graph, then we have .
Simplex‐based adaptive parametric model order reduction for applications in optimization
Authors: A. O. Leite Mateus , Delinchant Benoit , Guichon Jean‐Michel , A. Vasconcelos João 
Published: June 2017

AbstractA new methodology for optimization using parametric reduced order models is introduced. An adaptive scheme to place the expansion points in the reduction step is combined with a smart parametric space sampling in the optimization step to produce very reliable reduced order models. The methodology is illustrated in a demonstrative electromagnetic problem with appreciable gain in computational time. This technique is of general application and can be used to speed up optimization processes in many areas of engineering.
What matters for work engagement? A diary study on resources and the benefits of selective optimization with compensation for state work engagement
Authors: Venz Laura , Pundt Alexander , Sonnentag Sabine 
Published: June 2017

SummaryThis diary study addresses the benefits of employees' daily use of selective optimization with compensation (SOC) for state work engagement. We hypothesized that day‐level SOC not only directly fosters work engagement but that SOC also reveals its beneficial effects for work engagement in interaction with both external and internal resources. Specifically, we proposed SOC substitutes for job control, role clarity, and state of being recovered, thus helping employees manage low daily levels of these resources. We tested our hypotheses with a sample of 138 employees who completed two daily surveys over a total of 545 workdays. Results of multilevel analyses revealed that SOC benefits work engagement in both proposed ways. First, day‐level SOC was positively related to state work engagement. Additionally, day‐level role clarity and state of being recovered predicted state work engagement, but day‐level job control did not. Second, SOC benefitted state work engagement by offsetting low levels of role clarity and being recovered, and by boosting job control in their respective relationships with work engagement. The results suggest that by using SOC at work, employees can actively enhance their own work engagement on a given workday. This knowledge provides promising starting points for the development of interventions.
Application of a dispersive solid‐phase extraction method using an amino‐based silica‐coated nanomagnetic sorbent for the trace quantification of chlorophenoxyacetic acids in water samples
Authors: Ghambarian Mahnaz , Behbahani Mohammad , Esrafili Ali , Sobhi Hamid Reza 
Published: June 2017

AbstractHerein, an amino‐based silica‐coated nanomagnetic sorbent was applied for the effective extraction of two chlorophenoxyacetic acids (2‐methyl‐4‐chlorophenoxyacetic acid and 2,4‐dichlorophenoxyacetic acid) from various water samples. The sorbent was successfully synthesized and subsequently characterized by scanning electron microscopy, X‐ray diffraction, and Fourier‐transform infrared spectroscopy. The analytes were extracted by the sorbent mainly through ionic interactions. Once the extraction of analytes was completed, they were desorbed from the sorbent and detected by high‐performance liquid chromatography with ultraviolet detection. A number of factors affecting the extraction and desorption of the analytes were investigated in detail and the optimum conditions were established. Under the optimum conditions, the calibration curves were linear over the concentration range of 1–250, and based on a signal‐to‐noise ratio of 3, the method detection limits were determined to be 0.5 μg/L for both analytes. Additionally, a preconcentration factor of 314 was achieved for the analytes. The average relative recoveries obtained from the fortified water samples varied in the range of 91–108% with relative standard deviations of 2.9–8.3%. Finally, the method was determined to be robust and effective for environmental water analysis.
Correlation distance dependence of the resonance frequency of intermolecular zero quantum coherences and its implication for MR thermometry
Authors: Zhang Le , McCallister Andrew , Koshlap Karl M. , Branca Rosa Tamara 
Published: June 2017

PurposeBecause the resonance frequency of water–fat intermolecular zero‐quantum coherences (iZQCs) reflects the water–fat frequency separation at the microscopic scale, these frequencies have been proposed and used as a mean to obtain more accurate temperature information. The purpose of this work was to investigate the dependence of the water–fat iZQC resonance frequency on sample microstructure and on the specific choice of the correlation distance.MethodsThe effect of water–fat susceptibility gradients on the water–methylene iZQC resonance frequency was first computed and then measured for different water–fat emulsions and for a mixture of porcine muscle and fat. Similar measurements were also performed for mixed heteronuclear spin systems.ResultsA strong dependence of the iZQC resonance frequency on the sample microstructure and on the specific choice of the correlation distance was found for spin systems like water and fat that do not mix, but not for spin systems that mix at the molecular level.ConclusionsBecause water and fat spins do not mix at the molecular level, the water–fat iZQC resonance frequency and its temperature coefficient are not only affected by sample microstructure but also by the specific choice of the correlation distance. Magn Reson Med 79:1429–1438, 2018. © 2017 International Society for Magnetic Resonance in Medicine.
Goal‐oriented adaptivity using unconventional error representations for the multidimensional Helmholtz equation
Authors: Darrigrand Vincent , Rodríguez‐Rozas Ángel , Muga Ignacio , Pardo David , Romkes Albert , Prudhomme Serge 
Published: June 2017

SummaryIn goal‐oriented adaptivity, the error in the quantity of interest is represented using the error functions of the direct and adjoint problems. This error representation is subsequently bounded above by element‐wise error indicators that are used to drive optimal refinements. In this work, we propose to replace, in the error representation, the adjoint problem by an alternative operator. The main advantage of the proposed approach is that, when judiciously selecting such alternative operator, the corresponding upper bound of the error representation becomes sharper, leading to a more efficient goal‐oriented adaptivity.While the method can be applied to a variety of problems, we focus here on two‐ and three‐dimensional (2‐D and 3‐D) Helmholtz problems. We show via extensive numerical experimentation that the upper bounds provided by the alternative error representations are sharper than the classical ones and lead to a more robust p‐adaptive process. We also provide guidelines for finding operators delivering sharp error representation upper bounds. We further extend the results to a convection‐dominated diffusion problem as well as to problems with discontinuous material coefficients. Finally, we consider a sonic logging‐while‐drilling problem to illustrate the applicability of the proposed method.