bluuebunny/crossref_metadata_2025_split huggingface dataset:
Intra‐ and inter‐supramolecular complexation of poly(butyl methacrylate)‐co‐2‐(1,2,3‐triazol‐4‐yl)pyridine copolymers induced by CoII, FeII, and EuIII ions monitored by molecular hydrodynamics methods
Authors: Pavlov Georges M. , Perevyazko Igor , Happ Bobby , Schubert Ulrich S. 
Published: June 2016

ABSTRACTPoly(butyl methacrylate) copolymers embedding bidentate 2‐(1,2,3‐triazol‐4‐yl)pyridine (trzpy) chelating units as comonomer in the side chains were synthesized by controlled radical addition‐fragmentation transfer (RAFT) polymerization. Intracomplexation and intercomplexation of the macromolecules of the poly(butyl methacrylate) copolymers containing 20 % mol of trzpy units induced by CoII, FeII, and EuIII ions were studied in the solutions by macromolecular hydrodynamics methods. The sedimentation velocity of extremely diluted copolymer solutions and the dynamic viscosity of moderately diluted solutions were studied in a wide range of the salts concentrations. Differences were observed with respect to the copolymer behavior in the presence of the Co2+, Fe2+, Eu3+ ions. These differences are namely due to the differences in the number of coordination bonds required for complex formation and not explicitly to the nature of the corresponding anions. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016, 54, 2632–2639
Sustainability design of concrete structures
Authors: Sakai Koji , Shibata Toshio , Kasuga Akio , Nakamura Hikaru 
Published: June 2016

AbstractConcrete became the most used material on Earth over 200 years following the invention of modern cement. The design concept has undergone a transition from the allowable stress design method, limit state design method, and to the performance‐based design method, in response to the evolution of materials, sophistication of experimental facilities, and advancement of computation skills. From the issues on resources and energy depletion, global warming, and resilience etc., it is necessary to create a new design framework taking into consideration the required performance beyond the conventional concept, in order to construct infrastructure and buildings in a more rational way. In other words, one should construct a design system which sets the continued existence of the diverse and rich global environment as its most important criterion of value. In this paper, the authors review the design and technology system developed in the past and discusses it based on the above‐mentioned new viewpoint, while constructing and presenting a new design system for concrete structures, focusing mainly on the concept of sustainability which is regarded as the most important in achieving conservation of the Earth's rich resources as well as sound socioeconomic activities of humankind in the future, and discusses its feasibility.
Distributed opportunistic scheduling for MIMO underlay cognitive radio networks
Authors: El Tanab Manal , Hamouda Walaa , Fahmy Yasmine 
Published: June 2016

AbstractCognitive radio networks have emerged to improve the utilization of the scarce spectrum. In this paper, we propose a distributed resource allocation algorithm that allocates resources opportunistically to the secondary users in a multiple‐input multiple‐output environment. In order to reduce the complexity and cost, antenna selection schemes are employed to allow the secondary communication using a single radio frequency chain. The proposed algorithm is proved theoretically and using simulations, to give a performance very close to that of a centralized one with lower delay and overhead. Furthermore, we introduce two techniques for the proposed algorithm based on the allowable data rates referred to as limited and maximum rates. We derive closed‐form expression for the consumed power and tight upper bounds for the average throughput achieved by each technique. A comparison between the proposed techniques is also provided. Both simulations and analytical results show that the proposed algorithm achieves high throughput with low complexity. Moreover, the results show that the tightness of the bounds improves with the diversity order. Finally, the proposed techniques are compared with two suggested random schemes to investigate their effectiveness. Copyright © 2016 John Wiley & Sons, Ltd.
Calculations of magnetically induced current densities: theory and applications
Authors: Sundholm Dage , Fliegl Heike , Berger Raphael J.F. 
Published: June 2016

A review of computational studies of magnetically induced current density susceptibilities in molecules and their relation to experiments is presented. The history of the investigation of magnetically induced current densities and ring currents in molecules is briefly covered. The theoretical development of relativistic and nonrelativistic computational approaches for computing current densities in closed‐shell and open‐shell molecules is discussed and different state of the art methods to interpret calculated current densities are reviewed. Numerical integration approaches to assess global, semilocal, and local aromatic properties of multiring molecules are presented and demonstrated on free‐base trans‐porphyrin. We show that numerical integration of the current density combined with guiding visualization techniques of the current flow is a powerful tool for studies of the aromatic character of complicated molecular structures such as annelated aromatic and antiaromatic rings. Representative applications are reported illustrating the importance of careful current density studies for organic and inorganic chemistry. The applications include calculations of current densities and current strengths for aromatic, antiaromatic, and nonaromatic molecules of different kind. Current densities in spherical, cylindrical, tetrahedral, toroidal, and Möbius‐twisted molecules are discussed. The aromatic character, current pathways, and current strengths of porphyrins are briefly highlighted. Aromatic properties of inorganic molecules are assessed based on current density calculations. Current strengths as a noninvasive tool to determine strengths of hydrogen bonds are discussed. WIREs Comput Mol Sci 2016, 6:639–678. doi: 10.1002/wcms.1270This article is categorized under:

Structure and Mechanism > Molecular Structures
Electronic Structure Theory > Ab Initio Electronic Structure Methods
Electronic Structure Theory > Density Functional Theory
Synthesis of a Series of Anionic Surfactants Derived from NP and their Properties as Emulsifiers for Reducing Viscosity of Highly Viscous Oil via Formation of O/W Emulsions
Authors: Bao Lei , Wang Hanwei , Wu Yongbin , Li Xingmin , Qiao Weihong 
Published: June 2016

AbstractA series of alkyl phenol polyoxyethylene glycidyl ether (NP‐n‐O) and alkyl phenol polyoxyethylene ether hydroxypropyl sulfonate (NP‐n‐S) surfactants was synthesized to explore emulsification viscosity reduction. The optimum sulfonation conditions were obtained through orthogonal experiments, the ratio of alkyl phenol polyoxyethylene glycidyl ether and sodium bisulfite 1:1.5, 100 °C, and 6 h. The effects of concentrations of the synthesized surfactants, pH values, emulsifying temperature (40 and 60 °C) and water content on emulsification viscosity reduction and the stability of the emulsion to Venezuela’s Orinoco heavy oil were investigated. The water diversion ratio of emulsion at the reservoir temperature (55 °C) in 30 days was taken as an index, the results show that under the conditions of a temperature of 40 °C, an oil/water ratio of 7:3 and a surfactant NP‐4‐S concentration of 0.5 %, emulsions can be formed with a viscosity reduction rate reaching up to 99.69 % and with a water diversion ratio in 30 days reaching 9.38 %; while at 60 °C and an oil/water ratio of 7:3, at an NP‐4‐S concentration of 1 %, the viscosity reduction rate can reach 99.55 % and water diversion ratio is merely 4.23 % in 30 days. The mixture of NP‐n‐S, xanthan gum and cocamidopropyl dimethylamine oxide (CAO‐30) at suitable concentration can greatly improve the emulsification viscosity reduction and emulsion stability, which gives an emulsion viscosity rate of over 98 %. Moreover, the emulsion can be stable for at least 30 days without water emerging.
Mental health, migration stressors and suicidal ideation among Latino immigrants in Spain and the United States
Authors: Fortuna L.R. , Álvarez K. , Ramos Ortiz Z. , Wang Y. , Mozo Alegría X. , Cook B.L. , Alegría M. 
Published: June 2016

AbstractBackgroundImmigration stress appears to augment the risk for suicide behaviors for Latinos. Yet, specific risk factors that contribute to suicidal ideation (SI) among diverse Latino immigrant populations are not well established.MethodsData were collected in Boston, Madrid and Barcelona using a screening battery assessing mental health, substance abuse risk, trauma exposure, demographics, and sociocultural factors. Prevalence rates of lifetime and 30-day SI were compared across sites. Logistic regression modeling was used to identify sociodemographic, clinical, and sociocultural-contextual factors associated with 30-day SI.ResultsFive hundred and sixty-seven Latino patients from primary care, behavioral health and HIV clinics and community agencies participated. Rates of lifetime SI ranged from 29–35%; rates for 30-day SI were 21–23%. Rates of SI were not statistically different between sites. Factors associated with SI included exposure to discrimination, lower ethnic identity, elevated family conflict, and low sense of belonging (P< 0.01). In the adjusted model, higher scores on depression, posttraumatic stress disorder, and trauma exposure were significantly associated with 30-day SI (OR = 1.14, 1.04, and 7.76, respectively). Greater number of years living in the host country was significantly associated with increased odds of having SI (OR = 2.22) while having citizenship status was associated with lower odds (OR = 0.45).ConclusionLatinos suffering depression, trauma exposure, and immigration stressors are more likely to experience SI. Despite differences in country of origin, education, and other demographic factors between countries, rates of SI did not differ. Recommendations for prevention and clinical practice for addressing suicidal ideation risk among Latino immigrants are discussed.
CFD analysis of hover performance of rotors at full- and model-scale conditions
Authors: Barakos G.N. , Jimenez Garcia A. 
Published: June 2016

ABSTRACTAnalysis of the performance of a 1/4.71 model-scale and full-scale Sikorsky S-76 main rotor in hover is presented using the multi-block computational fluid dynamics (CFD) solver of Glasgow University. For the model-scale blade, three different tip shapes were compared for a range of collective pitch and tip Mach numbers. It was found that the anhedral tip provided the highest Figure of Merit. Rigid and elastic full-scale S-76 rotor blades were investigated using a loosely coupled CFD/Computational Structural Dynamics (CSD) method. Results showed that aeroelastic effects were more significant for high thrust cases. Finally, an acoustic study was performed in the tip-path-plane of both rotors, showing good agreement in the thickness and loading noise with the theory. For the anhedral tip of the model-scale blade, a reduction of 5% of the noise level was predicted. The overall good agreement with the theory and experimental data demonstrated the capability of the present CFD method to predict rotor flows accurately.
ON THE INTERFACE BETWEEN OPTIMAL PERIODIC AND CONTINUOUS DIVIDEND STRATEGIES IN THE PRESENCE OF TRANSACTION COSTS
Authors: Avanzi Benjamin , Tu Vincent , Wong Bernard 
Published: June 2016

AbstractIn the classical optimal dividends problem, dividend decisions are allowed to be made at any point in time — according to acontinuousstrategy. Depending on the surplus process that is considered and whether dividend payouts are bounded or not, optimal strategies are generally of a band, barrier or threshold type. In reality, while surpluses change continuously, dividends are generally paid on a periodic basis. Because of this, the actuarial literature has recently considered strategies where dividends are only allowed to be distributed at (random) discrete times — according to aperiodicstrategy.In this paper, we focus on the Brownian risk model. In this context, theoptimalcontinuous and periodic strategies have previously been shown (independently of one another) to be of barrier type. For the first time, we consider a model where both strategies are used. In such ahybridstrategy, decisions are allowed to be made either at any time (continuously), or periodically at a lower cost. This proves optimal in some cases. We also determine under which combination of parameters a pure continuous, pure periodic or hybrid (including both continuous and periodic dividend payments) barrier strategy is optimal. Interestingly, the hybrid strategy lies in-between periodic and continuous strategies, which provides some interesting insights. Results are illustrated.
Evaluation of a Healthcare-Associated Urinary Tract Infection Combination Antibiogram
Authors: Wick Jenna , Beaulac Kirthana , Doron Shira 
Published: June 2016

We created a 2013 combination antibiogram of healthcare-associated urinary tract infection. The 2013 antibiogram–determined regimen was evaluated in a 2014 cohort who had received empirical therapy. The regimen was statistically more likely to represent adequate treatment than actual prescriptions. A customized antibiogram may guide empirical therapy for specific patients.Infect Control Hosp Epidemiol 2016;37:1101–1104
Provenance of volcaniclastic beach sand in a magmatic-arc setting: an example from Lipari island (Aeolian archipelago, Tyrrhenian Sea)
Authors: MORRONE CONSUELE , DE ROSA ROSANNA , LE PERA EMILIA , MARSAGLIA KATHLEEN M. 
Published: June 2016

AbstractLipari, an active volcanic island in the Aeolian magmatic arc, is an excellent area to determine the effects of multiple source lithology, climate, weathering, transport and depositional environment on epiclastic sand composition. Volcaniclastic sand samples from 12 modern beaches were petrographically characterized using the Gazzi–Dickinson method, and the proportions of source rocks in combination with topography in associated coastal drainage basins were quantified using GIS. Several types of bedrock in the 12 drainage basins that are the likely prominent sources for sand at each sampled beach were recognized, and divided into two categories of provenance lithotypes: lavas and pyroclastic rocks ranging in composition from basaltic andesitic, to andesitic, to rhyolitic. Volcanic lithic fragments from Lipari beach sand consist of colourless and black glassy volcanic fragments with lathwork, felsitic, vitric and microlitic textures. Moreover, high amounts of detrital less durable minerals, such as pyroxene, olivine and Fe oxides, illustrate how the analysed sands preserve the source rock(s) provenance signals. Applying the concept of Sand Generation Index we see that these lithotypes have different propensities to create detritus, in terms of both grain-size and composition. Clastic contribution from pyroclastic rock outcrops such as pumice is not found in the size ranges studied, suggesting that these pumiceous source rocks probably only produce gravel or very fine sand and silt. This finding has implications for the stratigraphic record because pumice clasts, ranging from medium to fine grain-size, could be underrepresented in older volcaniclastic deposits and overrepresented in other size fractions.
Differences between root traits of early- and late-successional trees influence below-ground competition and seedling establishment
Authors: Zangaro Waldemar , Lescano Luis Eduardo Azevedo Marques , Matsuura Enio Massao , Rondina Artur Berbel Lirio , Nogueira Marco Antonio 
Published: June 2016

Abstract:The competitive influence of the root system of the exotic grassUrochloa brizanthaand the widespread forbLeonotis nepetifoliaon the emergence, survival and early growth of the seedlings of eight tropical heliophilous herbaceous species, six early-successional woody species and five late-successional woody species from Brazil, grown in 3500-cm3pots and in greenhouse without light restriction were assessed. The density of fine-root systems produced by the forb and the grass in pots were 6.8 cm cm−3soil and 48.1 cm cm−3soil, respectively. Seedlings survival of the heliophilous herbaceous, early- and late-successional woody species were 86%, 70% and 100% in presence of the forb root system and 12%, 14% and 100% in competition with grass root system, respectively. The competitive pressure applied by the grass root system on seedling growth of the heliophilous herbaceous, early- and late-successional woody species were 2.4, 1.9 and 1.4 times greater than the forb root system. Total root length of the heliophilous herbaceous, early- and late-successional woody species grown without competitors were 13, 33 and 5 times greater than in competition with forb, and were 66, 54 and 6 times greater than in competition with grass root system, respectively. The averages of fine-root diameter of plants grown without competitors were 209 μm for the heliophilous herbaceous, 281 μm for early-successional trees and 382 μm for late-successional trees. The root system of the forb did not avoid seedling establishment of most plant species, but the grass root system hampered more the establishment of heliophilous herbaceous and early-successional woody species than the seedling establishment of late-successional woody species. The different density of root systems produced in soil by the forb and the grass, and the distinct root traits (e.g. root diameter and root tissue density) of the early- and late-successional plant species can explain the differences in the establishment of seedlings of plant species belonging to different groups of tropical succession when exposed to below-ground competition.
MTHFD1 controls DNA methylation in Arabidopsis
Authors: Groth Martin , Moissiard Guillaume , Wirtz Markus , Wang Haifeng , Garcia-Salinas Carolina , Ramos-Parra Perla A. , Bischof Sylvain , Feng Suhua , Cokus Shawn J. , John Amala , Smith Danielle C. , Zhai Jixian , Hale Christopher J. , Long Jeff A. , Hell Ruediger , Díaz de la Garza Rocío I. , Jacobsen Steven E. 
Published: June 2016

AbstractDNA methylation is an epigenetic mechanism that has important functions in transcriptional silencing and is associated with repressive histone methylation (H3K9me). To further investigate silencing mechanisms, we screened a mutagenized Arabidopsis thaliana population for expression of SDCpro-GFP, redundantly controlled by DNA methyltransferases DRM2 and CMT3. Here, we identify the hypomorphic mutant mthfd1-1, carrying a mutation (R175Q) in the cytoplasmic bifunctional methylenetetrahydrofolate dehydrogenase/methenyltetrahydrofolate cyclohydrolase (MTHFD1). Decreased levels of oxidized tetrahydrofolates in mthfd1-1 and lethality of loss-of-function demonstrate the essential enzymatic role of MTHFD1 in Arabidopsis. Accumulation of homocysteine and S-adenosylhomocysteine, genome-wide DNA hypomethylation, loss of H3K9me and transposon derepression indicate that S-adenosylmethionine-dependent transmethylation is inhibited in mthfd1-1. Comparative analysis of DNA methylation revealed that the CMT3 and CMT2 pathways involving positive feedback with H3K9me are mostly affected. Our work highlights the sensitivity of epigenetic networks to one-carbon metabolism due to their common S-adenosylmethionine-dependent transmethylation and has implications for human MTHFD1-associated diseases.
Visualizing the formation of an RNA folding intermediate through a fast highly modular secondary structure switch
Authors: Xue Yi , Gracia Brant , Herschlag Daniel , Russell Rick , Al-Hashimi Hashim M. 
Published: June 2016

AbstractIntermediates play important roles in RNA folding but can be difficult to characterize when short-lived or not significantly populated. By combining 15N relaxation dispersion NMR with chemical probing, we visualized a fast (kex=k1+k−1≈423 s−1) secondary structural switch directed towards a low-populated (∼3%) partially folded intermediate in tertiary folding of the P5abc subdomain of the ‘Tetrahymena’ group I intron ribozyme. The secondary structure switch changes the base-pairing register across the P5c hairpin, creating a native-like structure, and occurs at rates of more than two orders of magnitude faster than tertiary folding. The switch occurs robustly in the absence of tertiary interactions, Mg2+ or even when the hairpin is excised from the three-way junction. Fast, highly modular secondary structural switches may be quite common during RNA tertiary folding where they may help smoothen the folding landscape by allowing folding to proceed efficiently via additional pathways.
Efficient generation of monoclonal antibodies against peptide in the context of MHCII using magnetic enrichment
Authors: Spanier Justin A. , Frederick Daniel R. , Taylor Justin J. , Heffernan James R. , Kotov Dmitri I. , Martinov Tijana , Osum Kevin C. , Ruggiero Jenna L. , Rust Blake J. , Landry Samuel J. , Jenkins Marc K. , McLachlan James B. , Fife Brian T. 
Published: June 2016

AbstractMonoclonal antibodies specific for foreign antigens, auto-antigens, allogeneic antigens and tumour neo-antigens in the context of major histocompatibility complex II (MHCII) are highly desirable as novel immunotherapeutics. However, there is no standard protocol for the efficient generation of monoclonal antibodies that recognize peptide in the context of MHCII, and only a limited number of such reagents exist. In this report, we describe an approach for the generation and screening of monoclonal antibodies specific for peptide bound to MHCII. This approach exploits the use of recombinant peptide:MHC monomers as immunogens, and subsequently relies on multimers to pre-screen and magnetically enrich the responding antigen-specific B cells before fusion and validation, thus saving significant time and reagents. Using this method, we have generated two antibodies enabling us to interrogate antigen presentation and T-cell activation. This methodology sets the standard to generate monoclonal antibodies against the peptide–MHCII complexes.
Vacuum Rabi splitting in a plasmonic cavity at the single quantum emitter limit
Authors: Santhosh Kotni , Bitton Ora , Chuntonov Lev , Haran Gilad 
Published: June 2016

AbstractThe strong interaction of individual quantum emitters with resonant cavities is of fundamental interest for understanding light–matter interactions. Plasmonic cavities hold the promise of attaining the strong coupling regime even under ambient conditions and within subdiffraction volumes. Recent experiments revealed strong coupling between individual plasmonic structures and multiple organic molecules; however, strong coupling at the limit of a single quantum emitter has not been reported so far. Here we demonstrate vacuum Rabi splitting, a manifestation of strong coupling, using silver bowtie plasmonic cavities loaded with semiconductor quantum dots (QDs). A transparency dip is observed in the scattering spectra of individual bowties with one to a few QDs, which are directly counted in their gaps. A coupling rate as high as 120 meV is registered even with a single QD, placing the bowtie-QD constructs close to the strong coupling regime. These observations are verified by polarization-dependent experiments and validated by electromagnetic calculations.