bluuebunny/crossref_metadata_2025_split huggingface dataset:
Monophosphine‐substituted diiron azadithiolate complexes: New syntheses, characterization and electrochemical properties
Authors: Wang Zheng , He Jiao , Lü Shuang , Jiang Wei‐Dong , Wu Yu , Jiang Jin , Xie Ying , Mu Chao , Li Ao , Li Yu‐Long , Li Qian‐Li 
Published: August 2019

Investigating the synthesis and properties of diiron azadithiolate complexes is one of the key topics for mimicking the active site of [FeFe]‐hydrogenases, which might be very useful for the design of new efficient catalysts for hydrogen production and the development of a future hydrogen economy. A series of new phosphine‐substituted diiron azadithiolate complexes as models for the active site of [FeFe]‐hydrogenases are described. A novel and efficient way was firstly established for the preparation of phosphine‐substituted diiron azadithiolate complexes. The reaction of Fe2(μ‐SH)2(CO)6 and phosphine ligands L affords the intermediate Fe2(μ‐SH)2(CO)5L (A). The intermediate reacts in situ with a premixed solution of paraformaldehyde and ammonium carbonate to produce the target phosphine‐substituted diiron azadithiolate complexes Fe2[(μ‐SCH2)2NH](CO)5L (1a–1f) (L = P(C6H4–4‐CH3)3, P(C6H4–3‐CH3)3, P(C6H4–4‐F)3, P(C6H4–3‐F)3, P(2‐C4H3O)3, PPh2(OCH2CH3)). Furthermore, reactions of the intermediate A with I‐4‐C6H4N(CH2Cl)2 in the presence of Et3N give the phosphine‐substituted diiron azadithiolate complexes Fe2[(μ‐SCH2)2NC6H4–4‐I](CO)5L (2a–2e) (L = P(C6H4–4‐CH3)3, P(C6H4–3‐CH3)3, P(C6H4–4‐F)3, P(C6H4–3‐F)3, P(2‐C4H3O)3). All the complexes were fully characterized using elemental analysis, IR and NMR spectroscopies and, particularly for 1a, 1c–1e, 2a and 2c, single‐crystal X‐ray diffraction analysis. In addition, complexes 1a–1f and 2a–2e were found to be catalysts for H2 production under electrochemical conditions. Density functional theory calculations were performed for the reactions of Fe2(μ‐SH)2(CO)6 + P(C6H4–4‐CH3)3.
In situ synthesis, structure, and properties of a dendritic branched nano‐thickening agent for high temperature fracturing fluid
Authors: Tang Jun , Li Haibo , Yan Shengdong , Yan Siming 
Published: August 2019

ABSTRACTThe aim of this work was to prepare a novel dendritic branched nano‐thickening agent by free radical polymerization of acrylamide (AM), acrylic acid (AA), sodium p‐styrene sulfonate, dimethyl diallyl ammonium chloride, and multiwalled carbon nanotubes. The as‐synthesized nano‐thickening agent was characterized by Fourier transform infrared, Raman spectra, transmission electron microscope, 1H‐NMR, and thermogravimetric analysis (TGA). Compared with the pristine polymer and partially hydrolyzed polyacrylamide (HPAM), thickening capacity, temperature resistance, and salt tolerance properties of the nano‐thickening agent considerably improved, and the viscosity of 0.5% nano‐polymer solution was 126.5 mPa·s. Additionally, the properties of the nano‐gel prepared by nano‐thickener, such as temperature and shear tolerance, viscoelasticity, sand carrying capacity, and gel breaking performance, were evaluated showing the satisfactory performance of the nano‐gel under high temperature condition. The results indicated that the nano‐thickener has potential applications in the field of oil and gas production. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020, 137, 48446.
Integrated design of robust fault estimation and fault‐tolerant control against simultaneous actuator and sensor faults
Authors: Mu Yunfei , Zhang Huaguang , Zhang Kun , Ren He 
Published: August 2019

AbstractThis paper investigates the problems of simultaneous actuator and sensor faults estimation, as well as the fault‐tolerant control scheme for a class of linear continuous‐time systems subject to external disturbances. First, the original system is transformed into a singular form by extending the actuator fault and sensor fault to be parts of the new state. Then, a new estimation technique named non‐fragile proportional‐derivative observer is designed for the singular system to achieve simultaneous estimations of states and faults. With the obtained estimations information, an integrated design of the non‐fragile output feedback fault‐tolerant controller is explored to compensate for the effect of faults by stabilizing the closed‐loop system. Finally, a simulation study on a two‐stage chemical reactor with recycle streams is provided to verify the effectiveness of the proposed approach.
Modelling and simulation of nabla fractional dynamic systems with nonzero initial conditions
Authors: Wei Yiheng , Wang Jiachang , Tse Peter W. , Wang Yong 
Published: August 2019

AbstractThe paper focuses on the numerical approximation of discrete fractional order systems with the conditions of nonzero initial instant and nonzero initial state. First, the inverse nabla Laplace transform is developed and the equivalent infinite dimensional frequency distributed model of discrete fractional order system is introduced. Then, resorting the nabla discrete Laplace transform, the rationality of the finite dimensional frequency distributed model approaching the infinite one is illuminated. Based on this, an original algorithm to estimate the parameters of the approximate model is proposed with the help of vector fitting method. Additionally, the applicable object is extended from a sum operator to a general system. Three numerical examples are performed to illustrate the applicability and flexibility of the introduced methodology.
Social‐media use and academic performance among undergraduates in biology
Authors: Shen Jie 
Published: August 2019

AbstractThe development of social media applications has made it an important part of students' personal lives. In this article, we aim to determine whether social media usage is beneficial or harmful to college students through academic performance. Through a survey of biological undergraduates, we found that boys use social media applications more frequently than girls, and that GPA is inversely related to the number of social media applications that students subscribe to. In addition, we found that using more social media applications is positively related to the amount of time spent on social media per day. Our research shows that social media may have a negative impact on undergraduates’ study habits and academic performance. © 2019 International Union of Biochemistry and Molecular Biology, 47(6):615–619, 2019.
Simultaneous determination of polyphenols and triterpenes in pomegranate peel based on high‐performance liquid chromatography fingerprint by solvent extraction and ratio blending method in tandem with wavelength switching
Authors: Ding Wenzheng , Wang Hanxue , Zhou Quan , Wu Chao , Gao Xiaoli , Cheng Xuemei , Tian Li , Wang Changhong 
Published: August 2019

AbstractTraditionally, pomegranate (Punica granatum L.) has been consumed as fresh fruit or as pomegranate juice. Pomegranate peel, the dried husk of P· granatum, is an important herbal medicine for treating diarrhea, hemostasis and insect‐induced abdominal pain in China. However, the quality control methods for pomegranate peel remain unsatisfactory. In this work, a new HPLC‐based qualitative and quantitative method for quality control of pomegranate peel was developed and validated for the simultaneous determination of polyphenols and triterpenes (including punicalagins A and B, ellagic acid, oleanolic acid and ursolic acid) by solvent extraction and ratio blending method in tandem with wavelength switching. The average recoveries were 98.07–100.61% with relative standard deviation no more than 4.27%. In addition, the fingerprint analysis was conducted to interpret the consistency of the quality test. Thirteen characteristic peaks were selected to evaluate the similarities of 16 batches of pomegranate peel. The similarities of samples were all more than 0.80, indicating that the samples from different areas of China were consistent. The results demonstrated that quantitative analysis and the HPLC fingerprint as a characteristic distinguishing method combining similarity evaluation can be successfully used to assess the quality and to identify the authenticity of pomegranate peel.
Development, validation and comparison of four methods for quantifying endogenous 25OH‐D3 in human plasma
Authors: Li Yan‐yan , Jiang Yi , Liu Li , Guo Hai‐yang , Cao Hai‐wei , Ji Zheng‐chao 
Published: August 2019

AbstractTo meet the increasing clinical needs for 25‐hydroxyvitamin D3 (25OH‐D3) detection, the development of an efficient and accurate high‐performance liquid chromatography–mass spectrometry (HPLC–MS) method for plasma 25OH‐D3 quantitation is important. Since 25OH‐D3 is an endogenous compound, the lack of a plasma blank increases the difficulty of accurately quantifying 25OH‐D3. Selection of a method suitable for clinical monitoring among various methods for endogenous compound quantification is necessary. Methyl tert butyl ether was chosen for the sample treatment in a liquid–liquid extraction protocol. Water as a blank matrix, 5% human serum albumin in water as a blank matrix, surrogate analyte and background subtraction were designed to address the problem of a deficiency of a plasma blank. Four liquid chromatography–tandem mass spectrometry methods were fully validated to verify the advantages and limitations owing to regulatory deficiencies for endogenous compound validation. All four methods met the criteria and could be used to monitor clinical samples. Overall 30 human plasma samples were quantified in parallel using the four methods. The difference between any two methods was <12.6% and the total relative standard deviation was <5.2%. Background subtraction and 5% human serum albumin in water as a blank matrix may be better choices considering data quality, matrix similarity, cost and practicality.
Demonstration of exogenous nuclear histone H3 binding to mitochondria and subsequent cytochrome c release in cauliflower
Authors: Major Linda A. , Sauterer Roger 
Published: August 2019

AbstractThe life cycle of a cell is partly regulated by the programmed cell death (PCD) process. From development to demise, a cell's PCD process must respond to external signals and internal factors mediated by mitochondria. Previous studies show that the release of histones into the cytosol caused by DNA damage or loss of nuclear integrity is correlated with apoptosis in mammalian cells. These released histones bind to mitochondria and permeabilize its inner and outer membranes, which causes the release of cytochrome c into the cytosol that leads to caspase activation and the demise of the cell. Owing to the high conservation of histones, we hypothesize that histone‐mediated cytochrome c release from mitochondria may be conserved across a wide range of eukaryotes. We investigated this histone–mitochondrial interaction in cauliflower using density‐gradient purified mitochondria and exogenous histones from a crude histone fraction, then added the exogenous histone fractions to the purified cauliflower mitochondria and analyzed the mitochondrial pellets and supernatants by immunoblotting against cytochrome c and H3. Our data clearly shows that histone‐enriched fractions elicited cytochrome c release from mitochondria, and that mitochondria bind exogenous histone H3.
P‐Type Boron‐Doped Monolayer Graphene with Tunable Bandgap for Enhanced Photocatalytic H2 Evolution under Visible‐Light Irradiation
Authors: Wu Yujun , Han Zhanli , Younas Waqar , Zhu Youqi , Ma Xilan , Cao Chuanbao 
Published: August 2019

AbstractGraphene‐based materials are considered as one of the promising photocatalysts for hydrogen production from solar‐driven water splitting yet subject to zero bandgap limitation. Here, we report an efficient one‐step pyrolysis for preparing p‐type boron‐doped monolayer graphene. Through varying the dopant content, the bandgap of the boron‐doped graphene can be tuned. Moreover, a p‐type conductivity behavior of the boron‐doped monolayer graphene is demonstrated by the four‐probe measurement and Hall effect measurement. The boron‐doped graphene can service as an efficient semiconductor photocatalyst for hydrogen production from water splitting under visible‐light irradiation. The optimized boron‐doped graphene can deliver a high H2 production rate of 219.3 μmol h−1 g−1 without any cocatalyst. The photocatalyst can be recycled at least four times without obvious activity decay and maintain high H2 production rate of 215.3 μmol h−1 g−1 after 60 h reaction, indicative of excellent stability. This work may open up a new avenue for fabrication of new photocatalysts based on p‐type boron‐doped monolayer graphene.
The Stereoselective Formation of trans‐Cumulene through Dehalogenative Homocoupling of Alkenyl gem‐Dibromides on Cu(110)
Authors: Cai Liangliang , Kang Faming , Sun Qiang , Gao Wenze , Yu Xin , Ma Honghong , Yuan Chunxue , Xu Wei 
Published: August 2019

AbstractStereoselective synthesis of geometrically pure isomers is challenging and important in a variety of chemistry related disciplines and applications. The recently developed on‐surface synthesis strategy provides us opportunities in the fabrication of specific nanostructures which remain challenging by conventional solution chemistry. In this work, we choose alkenyl gem‐dibromides as molecular precursors, and demonstrate the formation of specific trans‐cumulene products via C−C couplings on Cu(110). This study supplements the database of on‐surface synthesis strategies by introducing the alkenyl gem‐dibromide group on the surface. More importantly, it provides a way to stereoselective synthesis of specific isomers involving C−C double bonds, which may be of substantial utility in stereochemistry.
Cobalt Nanoparticles Apically Encapsulated by Nitrogen‐doped Carbon Nanotubes for Oxidative Dehydrogenation and Transfer Hydrogenation of N‐Heterocycles
Authors: Xu Dan , Zhao Hong , Dong Zhengping , Ma Jiantai 
Published: August 2019

AbstractIt is important to develop a highly active and stable transition‐metal catalyst with dual‐functional properties in the reversible transformations between various saturated and unsaturated N‐heterocycles. Herein, we prepared the cobalt nanoparticles (Co NPs) apically encapsulated by the N‐doped carbon nanotubes catalyst (Co@NCNTs) via a multiple pyrolysis of low‐cost dicyandiamide and cobalt (II) acetylacetonate. The catalyst shows excellent activity and recyclability towards the oxidative dehydrogenation (ODH) and the catalytic transfer hydrogenation (CTH) for various N‐heterocycles. The structure of outer N‐doped carbon nanotubes (NCNTs) can protect Co NPs from aggregation and leaching. Moreover, the encapsulated Co NPs and the NCNTs may generate a synergistic effect. Both of them facilitate the high performance. The poisoning tests with KSCN were to clarify the different active sites for ODH and CTH reactions: the Co NPs could modify the NCNTs through electrons redistribution, therefore the NCNTs could directly activate O2 in ODH. The encapsulated Co NPs is enhanced by the doped N atoms which is good for the H2 activation in CTH. What's more, the mechanisms of ODH and CTH reactions were also proposed. This work provides a facile and low‐cost method to design catalysts, which are dual‐functional, highly active and stable, for industrial applications.
Chemoenzymatic Synthesis of an Odanacatib Precursor through a Suzuki‐Miyaura Cross‐Coupling and Bioreduction Sequence
Authors: González‐Martínez Daniel , Gotor Vicente , Gotor‐Fernández Vicente 
Published: August 2019

AbstractA series of 1‐aryl‐2,2,2‐trifluoroethanones has been chemically synthesized to later study their bioreduction using stereocomplementary alcohol dehydrogenases (ADHs). Satisfyingly, (R)‐alcohols were obtained in high conversions and selectivities using the ADH from Ralstonia species and the one from Rhodococcus ruber, while the (S)‐enantiomers were independently produced using the ADH from Lactobacillus brevis and the commercially available evo‐1.1.200. In the search for a stereoselective route towards the Odanacatib, an orally bioavailable and selective inhibitor of Cathepsin K, the development of a sequential methodology combining a palladium‐catalyzed cross coupling between 1‐(4‐bromophenyl)‐2,2,2‐trifluoroethanone and 4‐(methylsulfonyl)phenylboronic acid in aqueous medium with the bioreduction of the resulting 2,2,2‐trifluoro‐1‐(4′‐(methylsulfonyl)‐[1,1′‐biphenyl]‐4‐yl)ethanone has been extensively studied. Finally, the desired (R)‐2,2,2‐trifluoro‐1‐(4′‐(methylsulfonyl)‐[1,1′‐biphenyl]‐4‐yl)ethanol was obtained in enantiomerically pure form and 85 % yield with a 128 g L−1 d−1 productivity following a sequential approach.
Iterative deflation algorithm, eigenvalue equations, and PLS2
Authors: Stocchero Matteo 
Published: August 2019

AbstractPLS2 is probably the most used algorithm to perform projection to latent structures regression in the case of multivariate response. However, several criticisms pointed to the theoretical limits of its original formulation, highlighting the need of a more robust foundation within the theory of regression analysis. The iterative deflation algorithm is here introduced as a starting point to obtain a family of regression methods, which includes PLS2, principal component regression (PCR), and elastic component regression (ECR), where different eigenvalue equations are used to calculate the weight vectors. Within this framework, an original portrait of PLS2 is drawn. The main mathematical properties useful to understand what PLS2 is and how PLS2 behaves are derived. A new regression method called iterative deflation algorithm‐based regression (IDAR) is introduced to describe the limit behaviour of PLS2, PCR, and ECR. The post‐transformation method is presented as a general property of the iterative deflation algorithm. Two data sets, one simulated and the other experimental, are investigated to illustrate the main properties of PLS2.
Bidirectional Hiyama–Denmark Cross‐Coupling Reactions of Bissilyldeca‐1,3,5,7,9‐pentaenes for the Synthesis of Symmetrical and Non‐Symmetrical Carotenoids
Authors: Rivas Aurea , Pérez‐Revenga Víctor , Alvarez Rosana , de Lera Angel R. 
Published: August 2019

AbstractThe construction of the carotenoid skeleton by Pd‐catalyzed Csp2−Csp2cross‐coupling reactions of symmetrical and non‐symmetrical 1,10‐bissilyldeca‐1,3,5,7,9‐pentaenes and the corresponding complementary alkenyl iodides has been developed. Reaction conditions for these bidirectional and orthogonal Hiyama–Denmark cross‐coupling reactions of bisfunctionalized pentaenes are mild and the carotenoid products preserve the stereochemical information of the corresponding oligoene partners. The carotenoids synthesized in this manner include β,β‐carotene and (3R,3′R)‐zeaxanthin (symmetrical) as well as 9‐cis‐β,β‐carotene, 7,8‐dihydro‐β,β‐carotene and β‐cryptoxanthin (non‐symmetrical).
Lattice Shrinkage by Incorporation of Recombinant Starmaker‐Like Protein within Bioinspired Calcium Carbonate Crystals
Authors: Różycka Mirosława , Coronado Ismael , Brach Katarzyna , Olesiak‐Bańska Joanna , Samoć Marek , Zarębski Mirosław , Dobrucki Jerzy , Ptak Maciej , Weber Eva , Polishchuk Iryna , Pokroy Boaz , Stolarski Jarosław , Ożyhar Andrzej 
Published: August 2019

AbstractInvited for the cover of this issue is the group of Mirosława Różycka and Andrzej Ożyhar at the Wroclaw University of Science and Technology, and colleagues at Jagiellonian University, the Polish Academy of Sciences, and Technion Israel Institute of Technology. The image depicts confocal laser scanning images showing the effect of the protein involved in the formation of otoliths on the calcium carbonate crystal lattice reported in the paper. Read the full text of the article at 10.1002/chem.201902157.
Supramolecular Organization of Model Polycyclic Aromatic Molecules: Comparison of 2D and 3D Assemblies
Authors: Raj Gijo , Kikkawa Yoshihiro , Catalano Luca , Pasricha Renu , Norikane Yasuo , Naumov Panče 
Published: August 2019

AbstractThe spatial organization of polycyclic aromatic molecules during adhesion on a solid/liquid interface is the key event of a plethora of natural and industrial processes. Herein, we report the supramolecular assembly of violanthrone‐79—a model of asphaltenes, an intractable mixture of polycyclic aromatics from crude oil—at the solid‐liquid interface between highly oriented pyrolytic graphite (HOPG) and a hydrophobic medium (1‐phenyloctane). High‐resolution scanning tunneling microscopy revealed that molecules of violanthrone‐79 readily self‐assemble on the surface in supramolecular “nanoring” structures. The lattice parameters of the 2D unit cell are on the same order as those determined from a bulk single crystal. Transmission electron microscopy showed long‐range ordered patterns, and the spacing between the fringes is in agreement with the inter‐planar distances between aromatic cores of molecules that are helically arranged around the [001] axis in the 3D crystal. The results confirm that upon adsorption on solid/liquid interfaces, polycyclic aromatic molecules such as violanthrone‐79 form supramolecular assemblies by interaction with the substrate and self‐association, and this process could be the initial step of deposition of asphaltenes on carbonaceous oil reservoir walls and production tubing.
Tris(pentafluorophenyl)borane‐pyrrolo[3,2‐b]pyrrole Hybrids: Solid‐State Structure and Crystallization‐Induced Enhanced Emission
Authors: Hatanaka Sou , Ono Toshikazu , Yano Yoshio , Gryko Daniel T. , Hisaeda Yoshio 
Published: August 2019

AbstractThe work demonstrates that the quadrupolar nature of acceptor‐donor‐acceptor pyrrolo[3,2‐b]pyrrole systems can be substantially modified via the formation of boron‐nitrogen (B−N) bonds between peripheral CN groups and B(C6F5)3. This coordination enables a strong bathochromic shift of emission for both the solid crystalline state as well as in certain solvents. The B−N complex, or co‐crystal, was effectively isolated from the reaction between a pyrrolo[3,2‐b]pyrrole with two cyanophenyl moieties and tris(pentafluorophenyl)borane (TPFB), which were mixed in non‐polar solvents or prepared via liquid‐assisted solid‐state synthesis in a ball mill. An investigation of the structure‐property relationship confirmed that the intermolecular B−N bond influences the bathochromic shift in the absorption and emission spectra and that crystallization‐induced emission enhancement was observed owing to the benefits of the molecular packing style and the intermolecular C−H⋅⋅⋅F interactions. The postsynthetic strategy involves hybridization of molecules on a molecular level, which should provide a variety of novel photofunctional materials.
Cross‐Linked Nanocellulosic Materials and Their Applications
Authors: Liang Luna , Bhagia Samarthya , Li Mi , Huang Chen , Ragauskas Arthur J. 
Published: August 2019

AbstractNanocelluloses (NCs) have remarkable mechanical properties and contain abundant surface functional groups that can be modified or cross‐linked with other materials. They have been widely used as an environment‐friendly reinforcing agent in polymer composites. However, for applications that are carried out in humid environments or aqueous suspensions, hydrophilicity of NCs lower their mechanical integrity. Hence, cross‐linking techniques have been investigated in recent years for preparing NC‐based materials that are dimensionally stable under humid or aqueous environments and have better physicochemical properties. This Minireview examines the quickly growing field of cross‐linked NC‐based materials, which have many benefits including improved aqueous, structural, mechanical, and thermal stability. In addition, the potential application of cross‐linked NC‐based materials in adsorption of heavy metal is discussed.