bluuebunny/crossref_metadata_2025_split huggingface dataset:
Hierarchical Porous Carbonized Co3O4 Inverse Opals via Combined Block Copolymer and Colloid Templating as Bifunctional Electrocatalysts in Li–O2 Battery
Authors: Cho Seol A. , Jang Yu Jin , Lim Hee‐Dae , Lee Ji‐Eun , Jang Yoon Hee , Nguyen Trang‐Thi Hong , Mota Filipe Marques , Fenning David P. , Kang Kisuk , Shao‐Horn Yang , Kim Dong Ha 
Published: July 2017

AbstractHierarchically organized porous carbonized‐Co3O4 inverse opal nanostructures (C‐Co3O4 IO) are synthesized via complementary colloid and block copolymer self‐assembly, where the triblock copolymer Pluronic P123 acts as the template and the carbon source. These highly ordered porous inverse opal nanostructures with high surface area display synergistic properties of high energy density and promising bifunctional electrocatalytic activity toward both the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER). It is found that the as‐made C‐Co3O4 IO/Ketjen Black (KB) composite exhibits remarkably enhanced electrochemical performance, such as increased specific capacity (increase from 3591 to 6959 mA h g−1), lower charge overpotential (by 284.4 mV), lower discharge overpotential (by 19.0 mV), and enhanced cyclability (about nine times higher than KB in charge cyclability) in Li–O2 battery. An overall agreement is found with both C‐Co3O4 IO/KB and Co3O4 IO/KB in ORR and OER half‐cell tests using a rotating disk electrode. This enhanced catalytic performance is attributed to the porous structure with highly dispersed carbon moiety intact with the host Co3O4 catalyst.
Fetal hemoglobin in sickle cell anemia: The Arab‐Indian haplotype and new therapeutic agents
Authors: Habara Alawi H. , Shaikho Elmutaz M. , Steinberg Martin H. 
Published: July 2017

AbstractFetal hemoglobin (HbF) has well‐known tempering effects on the symptoms of sickle cell disease and its levels vary among patients with different haplotypes of the sickle hemoglobin gene. Compared with sickle cell anemia haplotypes found in patients of African descent, HbF levels in Saudi and Indian patients with the Arab‐Indian (AI) haplotype exceed that in any other haplotype by nearly twofold. Genetic association studies have identified some loci associated with high HbF in the AI haplotype but these observations require functional confirmation. Saudi patients with the Benin haplotype have HbF levels almost twice as high as African patients with this haplotype but this difference is unexplained. Hydroxyurea is still the only FDA approved drug for HbF induction in sickle cell disease. While most patients treated with hydroxyurea have an increase in HbF and some clinical improvement, 10 to 20% of adults show little response to this agent. We review the genetic basis of HbF regulation focusing on sickle cell anemia in Saudi Arabia and discuss new drugs that can induce increased levels of HbF.
Internal diversification of non‐Sub‐Saharan haplogroups in Sahelian populations and the spread of pastoralism beyond the Sahara
Authors: Kulichová Iva , Fernandes Verónica , Deme Alioune , Nováčková Jana , Stenzl Vlastimil , Novelletto Andrea , Pereira Luísa , Černý Viktor 
Published: July 2017

AbstractBackgroundToday, African pastoralists are found mainly in the Sahel/Savannah belt spanning 6,000 km from west to east, flanked by the Sahara to the north and tropical rainforests to the south. The most significant group among them are the Fulani who not only keep cattle breeds of possible West Eurasian ancestry, but form themselves a gene pool containing some paternally and maternally‐transmitted West Eurasian haplogroups.Materials and MethodsWe generated complete sequences for 33 mitogenomes belonging to haplogroups H1 and U5 (23 and 10, respectively), and genotyped 16 STRs in 65 Y chromosomes belonging to haplogroup R1b‐V88.ResultsWe show that age estimates of the maternal lineage H1cb1, occurring almost exclusively in the Fulani, point to the time when the first cattle herders settled the Sahel/Savannah belt. Similar age estimates were obtained for paternal lineage R1b‐V88, which occurs today in the Fulani but also in other, mostly pastoral populations. Maternal clade U5b1b1b, reported earlier in the Berbers, shows a shallower age, suggesting another possibly independent input into the Sahelian pastoralist gene pool.ConclusionsDespite the fact that animal domestication originated in the Near East ∼ 10 ka, and that it was from there that animals such as sheep, goats as well as cattle were introduced into Northeast Africa soon thereafter, contemporary cattle keepers in the Sahel/Savannah belt show uniparental genetic affinities that suggest the possibility of an ancient contact with an additional ancestral population of western Mediterranean ancestry.
Fast Adsorption of Soft Hydrogel Microspheres on Solid Surfaces in Aqueous Solution
Authors: Matsui Shusuke , Kureha Takuma , Hiroshige Seina , Shibata Mikihiro , Uchihashi Takayuki , Suzuki Daisuke 
Published: July 2017

AbstractThe real‐time adsorption behavior of polymeric colloidal microspheres onto solid surfaces in aqueous solution was visualized for the first time using high‐speed atomic force microscopy (HS‐AFM) to reveal how the softness of the microspheres affects their dynamic adsorption. Studies that focus on the deformability of microspheres upon dynamic adsorption have not yet been reported, most likely on account of a lack of techniques that appropriately depict the dynamic adsorption and deformation behavior of individual microspheres at the nanoscale in real time. In this study, the deformability of microspheres plays a crucial role on the adsorption kinetics, that is, soft hydrogel microspheres adsorb faster than harder elastomeric or rigid microspheres. These results should provide insight towards development of new colloidal nanomaterials that exhibit effective adsorption on specific sites in aqueous solution.
Photon‐Induced Near‐Field Electron Microscopy of Eukaryotic Cells
Authors: Kaplan Mohammed , Yoo Byung‐Kuk , Tang Jau , Karam Tony E. , Liao Bolin , Majumdar Devdoot , Baltimore David , Jensen Grant J. , Zewail Ahmed H. 
Published: July 2017

AbstractPhoton‐induced near‐field electron microscopy (PINEM) is a technique to produce and then image evanescent electromagnetic fields on the surfaces of nanostructures. Most previous applications of PINEM have imaged surface plasmon‐polariton waves on conducting nanomaterials. Here, the application of PINEM on whole human cancer cells and membrane vesicles isolated from them is reported. We show that photons induce time‐, orientation‐, and polarization‐dependent evanescent fields on the surfaces of A431 cancer cells and isolated membrane vesicles. Furthermore, the addition of a ligand to the major surface receptor on these cells and vesicles (epidermal growth factor receptor, EGFR) reduces the intensity of these fields in both preparations. We propose that in the absence of plasmon waves in biological samples, these evanescent fields reflect the changes in EGFR kinase domain polarization upon ligand binding.
Asymmetric Synthesis of Tertiary Alcohols and Thiols via Nonstabilized Tertiary α‐Oxy‐ and α‐Thio‐Substituted Organolithium Species
Authors: Pulis Alexander P. , Varela Ana , Citti Cinzia , Songara Pradip , Leonori Daniele , Aggarwal Varinder K. 
Published: July 2017

AbstractNonstabilized α‐O‐substituted tertiary organolithium species are difficult to generate, and the α‐S‐substituted analogues are configurationally unstable. We now report that they can both be generated easily and trapped with a range of electrophiles with high enantioselectivity, providing ready access to a range of enantioenriched tertiary alcohols and thiols. The configurational stability of the α‐S‐organolithium species was enhanced by using a less coordinating solvent and short reaction times.
Unexpected Chiro‐Thermoresponsive Behavior of Helical Poly(phenylacetylene)s Bearing Elastin‐Based Side Chains
Authors: Arias Sandra , Freire Felix , Calderón Marcelo , Bergueiro Julian 
Published: July 2017

AbstractThe thermoresponsive behavior of an elastin‐based polymer can be altered by the polymeric macromolecular conformation. Thus, when the elastin basic amino acid sequence VPGVG is used as a pendant group of a poly(phenylacetylene) (PPA) its thermoresponsive behavior in water can be remotely detected through conformational changes on the formed helix. Circular dichroism at different temperatures shows an inversion of the first Cotton effect (450 nm) at 25.8 °C that matches with the cloud point temperature. The elastin‐based side‐chain poly(phenylacetylene) shows an upper critical solution temperature with low pH and concentration dependency, not expected in elastin‐based polymers. It was found that the polymer self‐assembles in water into spherical nanoparticles with hydrodynamic diameters of 140 nm at the hydrophobic state.
Sustainable plasticizer for butyl rubber cured by phenolic resin
Authors: Li Jiaxi , Isayev Avraam I. , Wang Qianhe , Soucek Mark D. 
Published: July 2017

ABSTRACTButyl rubber (also known as isobutylene isoprene rubber, IIR) containing plasticizers and cured by phenolic resin is widely used to manufacture rubber products exposed to high temperature environments. Therefore, carbon black (CB)‐filled IIR containing a petroleum‐based plasticizer [naphthenic oil (NO)] and environmentally friendly bio‐based plasticizers [soybean oil (SO) and norbornylized soybean oil (NSO)] cured by the brominated phenolic resin were studied. The NSO was prepared through the reaction of SO and dicyclopentadiene at different ratios. Gel fraction, crosslink density, curing behavior, thermal, mechanical, and aging properties of the CB‐filled IIR containing different oils were investigated. The addition of SO and NSO increased the thermal stability and decreased the crosslink density of the IIR vulcanizates compared to that of the IIR/NO vulcanizate. This was found to be due to the reaction between the phenolic resin and the bio‐based oils. Reducing the oil level increased the crosslink density of the IIR/SO and IIR/NSO vulcanizates, which in turn increased the modulus and tensile strength. Among various vulcanizates, the IIR/NSO vulcanizates showed the best overall hot air aging resistance. Results showed that NSO in the amount less than 10 phr could be a good replacement for the petroleum‐based plasticizer in IIR cured by phenolic resins. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 45500.
Lignin‐based carbon fibers: Accelerated stabilization of lignin fibers in the presence of hydrogen chloride
Authors: Yue Zhongren , Vakili Ahmad , Hosseinaei Omid , Harper David Paul 
Published: July 2017

ABSTRACTOrganosolv switchgrass lignin (SGL) and hardwood lignin (HWL) polymers are used as precursors to prepare low cost carbon fibers (CFs). Lignin powder and fiber samples are stabilized and carbonized at different conditions to investigate the effect of HCl on thermal‐oxidative stabilization time, mass yield, fiber diameter, and mechanical properties. The results show that HCl can accelerate stabilization and reduce the stabilization time from many hours to 75 min for the SGL fibers, and to 35 min for the HWL fiber. The rate of rapid stabilization in HCl/air is at least four times faster than conventional stabilization in air. The CFs prepared with two different stabilization methods have almost the same strength and modulus, but higher carbon yield is obtained with the rapid stabilization due to a short time of oxidation. Pores and defects observed on the surface and the cross‐section of the CFs across all stabilization conditions contribute to low fiber strength. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 45507.
A Continuous Process for the Purification of Terpenyl Amines Using a Reversible Acid‐Base Reaction
Authors: Färber Tobias , Behr Arno , Fink Natalia , Koop Jörg 
Published: July 2017

AbstractThe reversible reactive extraction of long‐chain terpenyl amines (TPAs) using organic acids as reactive extractants was investigated. The scope of suitable acids has been extended and semicontinuous and continuous experiments were performed to prove the applicability of this concept. High extraction yields could be achieved using a variety of acids in batch and semicontinuous experiments. Furthermore, the recovery and separation of the extracted TPAs from the extractant phase has been studied. The TPAs can be recovered in high yields and purities by simple means of process parameter changes. The proposed process allows the separation and purification of TPAs in high yields and purities without the creation of salts or other chemical by‐products.
Thermally Activated Delayed Fluorescence in CuI Complexes Originating from Restricted Molecular Vibrations
Authors: Li Guangfu , Nobuyasu Roberto S. , Zhang Baohua , Geng Yun , Yao Bing , Xie Zhiyuan , Zhu Dongxia , Shan Guogang , Che Weilong , Yan Likai , Su Zhongmin , Dias Fernando B. , Bryce Martin R. 
Published: July 2017

AbstractThe mechanism of thermally activated delayed fluorescence (TADF) in molecules in aggregated or condensed solid states has been rarely studied and is not well understood. Nevertheless, many applications of TADF emitters are strongly affected by their luminescence properties in the aggregated state. In this study, two new isomeric tetradentate CuI complexes which simultaneously show aggregation induced emission (AIE) and TADF characteristics are reported for the first time. We provide direct evidence that effectively restricting the vibrations of individual molecules is a key requisite for TADF in these two CuI complexes through in‐depth photophysical measurements combined with kinetic methods, single crystal analysis and theoretical calculations. These findings should stimulate new molecular engineering endeavours in the design of AIE–TADF active materials with highly emissive aggregated states.
Component‐Customizable Porous Rare‐Earth‐Based Colloidal Spheres towards Highly Effective Catalysts and Bioimaging Applications
Authors: Li Cheng Chao , Rui Xianhong , Wei Weifeng , Chen Libao , Yu Yan 
Published: July 2017

AbstractMulticomponent porous colloidal spheres are of interest because they not only show a combination of the properties associated with all different components, but also usually present synergy effects. However, a combination of different components in a single porous sphere is still greatly challenged due to the different precipitation behaviors of each component. In this work, we have developed a general synthetic route to prepare several categories of porous monodisperse rare‐earth (RE)‐based colloidal spheres with customizable elemental compositions and a uniform element distribution. The two‐step synthetic strategy is based on the integration of coordination chemistry precipitation of RE ions and a subsequent ion‐exchange process, which steers clear of obstacles, such as differences in solubility product constant, that are to be found in traditional co‐precipitation methods. Our approach provides a new mixing mechanism to realize homogeneous distribution of each element within the porous spheres. An array of binary, ternary, and even senary RE colloidal porous spheres with diameters of 500 nm to 700 nm has been successfully synthesized. Taking advantage of their good dispersibility, porosity, and customizable components, these porous RE oxide spheres show excellent catalytic activity for the reduction of 4‐nitrophenol, and promising application in single‐phase multifunctional bioprobes.
Crystallization Caught in the Act with Terahertz Spectroscopy: Non‐Classical Pathway for l‐(+)‐Tartaric Acid
Authors: Soltani Amin , Gebauer Denis , Duschek Lennart , Fischer Bernd M. , Cölfen Helmut , Koch Martin 
Published: July 2017

AbstractCrystal formation is a highly debated problem. This report shows that the crystallization of l‐(+)‐tartaric acid from water follows a non‐classical path involving intermediate hydrated states. Analytical ultracentrifugation indicates solution clusters of the initial stages aggregate to form an early intermediate. Terahertz spectroscopy performed during water evaporation highlights a transient increase in the absorption during nucleation; this indicates the recurrence of water molecules that are expelled from the intermediate phase. Besides, a transient resonance at 750 GHz, which can be assigned to a natural vibration of large hydrated aggregates, vanishes after the final crystal has formed. Furthermore, THz data reveal the vibration of nanosized clusters in the dilute solution indicated by analytical ultracentrifugation. Infrared spectroscopy and wide‐angle X‐ray scattering highlight that the intermediate is not a crystalline hydrate. These results demonstrate that nanoscopic intermediate units assemble to form the first solvent‐free crystalline nuclei upon dehydration.
Synthesis of Benzofurans and Indoles from Terminal Alkynes and Iodoaromatics Catalyzed by Recyclable Palladium Nanoparticles Immobilized on Siliceous Mesocellular Foam
Authors: Bruneau Alexandre , Gustafson Karl P. J. , Yuan Ning , Tai Cheuk‐Wai , Persson Ingmar , Zou Xiaodong , Bäckvall Jan‐E. 
Published: July 2017

AbstractHerein, we report on the utilization of a heterogeneous catalyst, consisting of Pd nanoparticles supported on a siliceous mesocellular foam (Pd0‐AmP‐MCF), for the synthesis of heterocycles. Reaction of o‐iodophenols and protected o‐iodoanilines with acetylenes in the presence of a Pd nanocatalyst produced 2‐substituted benzofurans and indoles, respectively. In general, the catalytic protocol afforded the desired products in good to excellent yields under mild reaction conditions without the addition of ligands. Moreover, the structure of the reported Pd nanocatalyst was further elucidated with extended X‐ray absorption fine‐structure spectroscopy, and it was proven that the catalyst could be recycled multiple times without significant loss of activity.
Divergent Regio‐ and Stereoselective Gold‐catalyzed Synthesis of α‐Fluorosulfones and β‐Fluorovinylsulfones from Alkynylsulfones
Authors: Zeng Xiaojun , Liu Shiwen , Hammond Gerald B. , Xu Bo 
Published: July 2017

AbstractWe developed a widely applicable, highly efficient synthesis of α‐fluorosulfone and β‐fluorovinylsulfone catalyzed by gold. Starting with alkynyl sulfone 1, an [Au]/HF/N‐oxide system gives α‐fluorosulfone 3 via a gold carbene intermediate, and, if no N‐oxide is used, direct addition of HF to 1 gives vinyl sulfone 4 via a vinylfluoro gold intermediate. Both methods have good functional group tolerance and the reactions can be conducted in ambient atmosphere.
Testing perfect rankings in ranked‐set sampling with binary data
Authors: Frey Jesse , Zhang Yimin 
Published: July 2017

AbstractIn ranked‐set sampling, the rankings may be either perfect or imperfect. Statistical procedures that assume perfect rankings tend to be more efficient than procedures that do not assume perfect rankings when perfect rankings actually hold, but may perform poorly if the rankings are imperfect. Several procedures have been developed for testing the null hypothesis of perfect rankings, but these procedures break down if the data are not continuous. In this article, we develop tests of perfect rankings that can be applied with binary data. Motivated by new theoretical results about how the success probabilities in the judgment strata differ under perfect and imperfect rankings, we develop a consistent test with a test statistic that is asymptotically normal. We find, however, that the test does not properly control the type I error rate with small samples. This motivates us to instead implement a bootstrap version of the test. This bootstrap test controls the type I error rate even with small sample sizes. Functions for implementing both tests using R are available in the Supplementary Material. The Canadian Journal of Statistics 45: 326–339; 2017 © 2017 Statistical Society of Canada
Transforming the empirical likelihood towards better accuracy
Authors: Jing Bing‐Yi , Tsao Min , Zhou Wang 
Published: July 2017

AbstractUnder‐coverage has been a long‐standing issue with the empirical likelihood confidence region. Several methods can be used to address this issue, but they all add complexity to the empirical likelihood inference requiring extra computation and/or extra theoretical investigation. The objective of this article is to find a method that does not add complexity. To this end we look for a simple transformation of the empirical likelihood to alleviate the under‐coverage. Using several criteria concerning the accuracy, consistency, and preservation of the geometric appeal of the original empirical likelihood we obtain a transformed version of the empirical likelihood that is extremely simple in theory and computation. Its confidence regions are surprisingly accurate, even in small sample and multidimensional situations. It can be easily used to alleviate the under‐coverage problem of empirical likelihood confidence regions. The Canadian Journal of Statistics 45: 340–352; 2017 © 2017 Statistical Society of Canada
Fluorescent Metal–Organic Frameworks for Selective Sensing of Toxic Cations (Tl3+, Hg2+) and Highly Oxidizing Anions ((CrO4)2−, (Cr2O7)2−, (MnO4)−)
Authors: Jana Ajay Kumar , Natarajan Srinivasan 
Published: July 2017

AbstractThe ligand 4,4′‐(benzothiadiazole‐4,7‐diyl)dibenzoic acid was synthesized and employed for the synthesis of two metal–organic framework (MOF) compounds, [Mn4(C20H10N2O4S)2(HCOO)4(DEF)2] (I; DEF=N,N′‐diethylformamide) and [Pb(C20H10N2O4S)(DMF)] (II; DMF=N,N′‐dimethylformamide). Single‐crystal structure studies revealed that compound I has a three‐dimensional structure and compound II has a two‐dimensional structure. The luminescent nature of the MOFs was gainfully employed as a probe for the detection of highly toxic metal ions such as Tl3+ and Hg2+. The detection limits were found to be in the parts per billion (ppb) level. The presence of an unsubstituted thiadiazole ring in the ligand appears to help in the detection of these highly toxic metal ions in solution as the metal ions interact with S, which was revealed by Raman spectroscopic studies. The compounds were also found to be good candidates for the detection of highly oxidizing anions such as chromate, dichromate, and permanganate, again in ppb levels of concentration in solution. Magnetic studies on compound I indicate antiferromagnetic behavior. The variable‐temperature electrical conductivity studies indicate a semiconducting nature with comparable behavior to well‐known semiconductors such as CdSe, ZnTe, and GaP.
One‐Step Formation of 3D Alternating‐Layer Structures Composed of Plates of Nanocrystalline Bismuth Oxide and Spherical Particles of Metallic Bismuth
Authors: Bokhonov Boris B. , Yukhin Yurii M. 
Published: July 2017

AbstractThree‐dimensional (3D) objects with a periodic structure composed of particles differing in composition and/or morphology have attracted a lot of attention due to their high potential for achieving new sets of properties nonexistent in single‐phase materials and materials lacking a periodic structure. In this work, we have demonstrated a possibility of synthesizing a periodic heterostructure consisting of layers of nanocrystalline β‐bismuth oxide and layers of spherical particles of metallic bismuth in a single step by conducting partial reduction of [Bi6O5(OH)3](NO3)5·3H2O in benzyl alcohol. The synthesis method of micrometer‐sized particles of nanocrystalline β‐Bi2O3/spherical Bi with a 3D periodic structure is proposed in this work for the first time. The mechanisms governing the interface formation during the synthesis of the β‐Bi2O3/spherical Bi alternating‐layer structure are discussed. The structural evolution of [Bi6O5(OH)3](NO3)5·3H2O during its partial reduction in benzyl alcohol shows an example of the strong interrelation between the phase composition, morphology and architecture of the reaction products derived from a single‐phase precursor. The proposed synthesis method of the β‐Bi2O3/spherical Bi alternating‐layer 3D materials is easily scalable, shows good reproducibility and is based on simple experimental procedures.