bluuebunny/crossref_metadata_2025_split huggingface dataset:
Vapor‐Phase Linker Exchange of the Metal–Organic Framework ZIF‐8: A Solvent‐Free Approach to Post‐synthetic Modification
Authors: Marreiros João , Van Dommelen Lenz , Fleury Guillaume , de Oliveira‐Silva Rodrigo , Stassin Timothée , Iacomi Paul , Furukawa Shuhei , Sakellariou Dimitrios , Llewellyn Philip L. , Roeffaers Maarten , Ameloot Rob 
Published: October 2019

AbstractZeolitic imidazolate frameworks (ZIFs) are a sub‐class of metal–organic frameworks (MOFs). Although generally stable, ZIFs can undergo post‐synthetic linker exchange (PSLE) in solution under mild conditions. Herein, we present a novel, solvent‐free approach to post‐synthetic linker exchange through exposure to linker vapor.
Effect of Temperature on the Nucleation and Growth of Precious Metal Nanocrystals
Authors: Pitto‐Barry Anaïs , Barry Nicolas P. E. 
Published: October 2019

AbstractUnderstanding the effect of physical parameters (e.g., temperature) on crystallisation dynamics is of paramount importance for the synthesis of nanocrystals of well‐defined sizes and geometries. However, imaging nucleation and growth is an experimental challenge owing to the resolution required and the kinetics involved. Here, by using an aberration‐corrected transmission electron microscope, we report the fabrication of precious metal nanocrystals from nuclei and the identification of the dynamics of their nucleation at three different temperatures (20, 50, and 100 °C). A fast, and apparently linear, acceleration of the growth rate is observed against increasing temperature (78.8, 117.7, and 176.5 pm min−1, respectively). This work appears to be the first direct observation of the effect of temperature on the nucleation and growth of metal nanocrystals.
The Reactions of Carbon Monoxide with Silyl and Silenyl Lithium – Synthesis and Isolation of the First Stable Tetra‐Silyl Di‐Ketyl Biradical and 1‐Silaallenolate Lithium
Authors: Kratish Yosi , Pinchuk Daniel , Kaushansky Alexander , Molev Victoria , Tumanskii Boris , Bravo‐Zhivotovskii Dmitry , Apeloig Yitzhak 
Published: October 2019

AbstractReactions of carbon monoxide (CO) with tBu2MeSiLi and (E)‐(tBu2MeSi)(tBuMe2Si)C=Si(SiMetBu2)Li⋅2 THF (4) were studied both experimentally and computationally. Reaction of tBu2MeSiLi with CO in hexane yields the first stable tetra‐silyl di‐ketyl biradical [(tBu2MeSi)2COLi].2 (3). Reaction of 4 with CO yields selectively and quantitatively the first reported 1‐silaallenolate, (tBu2MeSi)(tBuMe2Si)C=C=Si(SiMetBu2)OLi⋅THF (5). Both 3 and 5 were characterized by X‐ray crystallography and biradical 3 also by EPR spectroscopy. Silaallenolate 5 reacts with Me3SiCl to produce siloxy substituted 1‐silaallene (tBu2MeSi)(tBuMe2Si)C=C=Si(SiMetBu2)OSiMe3. The reaction of 4 with CO provides a new route to 1‐silaallenes. The mechanisms of the reactions of tBuMe2SiLi and of 4 with CO were studied by DFT calculations.
Insight into Three‐Coordinate Aluminum Species on Ethanol‐to‐Olefin Conversion over ZSM‐5 Zeolites
Authors: Wang Zichun , O'Dell Luke A. , Zeng Xin , Liu Can , Zhao Shufang , Zhang Wenwen , Gaborieau Marianne , Jiang Yijiao , Huang Jun 
Published: October 2019

AbstractCommercial bioethanol can be readily converted into ethylene by a dehydration process using solid acids, such as Brønsted acidic H‐ZSM‐5 zeolites, and thus, it is an ideal candidate to replace petroleum and coal for the sustainable production of ethylene. Now, strong Lewis acidic extra‐framework three‐coordinate Al3+ species were introduced into H‐ZSM‐5 zeolites to improve their catalytic activity. Remarkably, Al3+ species working with Brønsted acid sites can accelerate ethanol dehydration at a much lower reaction temperature and shorten the unsteady‐state period within 1–2 h, compared to >9 h for those without Al3+ species, which can significantly enhance the ethanol dehydration efficiency and reduce the cost. The reaction mechanism, studied by solid‐state NMR, shows that strong Lewis acidic EFAl‐Al3+ species can collaborate with Brønsted acid sites and promote ethanol dehydration either directly or indirectly via an aromatics‐based cycle to produce ethylene.
Genetically Encoded Ratiometric RNA‐Based Sensors for Quantitative Imaging of Small Molecules in Living Cells
Authors: Wu Rigumula , Karunanayake Mudiyanselage Aruni P. K. K. , Shafiei Fatemeh , Zhao Bin , Bagheri Yousef , Yu Qikun , McAuliffe Kathleen , Ren Kewei , You Mingxu 
Published: October 2019

AbstractPrecisely determining the intracellular concentrations of metabolites and signaling molecules is critical in studying cell biology. Fluorogenic RNA‐based sensors have emerged to detect various targets in living cells. However, it is still challenging to apply these genetically encoded sensors to quantify the cellular concentrations and distributions of targets. Herein, using a pair of orthogonal fluorogenic RNA aptamers, DNB and Broccoli, we engineered a modular sensor system to apply the DNB‐to‐Broccoli fluorescence ratio to quantify the cell‐to‐cell variations of target concentrations. These ratiometric sensors can be broadly applied for live‐cell imaging and quantification of metabolites, signaling molecules, and other synthetic compounds.
Preformed particle gels with potential applicability for conformance control of oil reservoirs
Authors: Amaral Camila N. R. , Oliveira Priscila F. , Roman Isabella O. , Mansur Claudia R. E. 
Published: October 2019

ABSTRACTPreformed particle gel (PPG) is a particled superabsorbent crosslinking polymer that has been successfully applied to control conformance. The aim of this study was to develop and evaluate the properties of PPGs based on crosslinked partially hydrolyzed polyacrylamide with polyethyleneimine (PEI). The study was conducted into two steps: (1) the preparation of standard hydrogels, which were dried and grounded to obtain preformed particles, using the Sydansk strength code and rheology for evaluation and (2) the determination of the swelling degree from the PPGs under typical reservoir conditions (temperature of 90 °C and salinity int about 29,940 mg/L of total dissolved solids). Sydansk coding is a method that provides semiquantitative measures, and it is expressed in an alphabetic code from A to J. The results showed that the systems in ideal predetermined conditions (20,000 mg/L of HPAM, 4,500 mg/L of PEI, and crosslinking temperature of at 70 °C) allowed obtaining PPGs with Sydansk codes of F or H (highly deformable or slightly deformable nonfluid gel, respectively). According to the rheology tests, the systems had pseudoplastic behavior with characteristics of strong gels (G″/G′ < 0.1). Besides this, the swelling degree under reservoir conditions was independent of gel‐strength F or H that in both cases is around 19%, but increases with increasing temperature. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020, 137, 48554.
Functionalized polyesters derived from glycerol: Selective polycondensation methods toward glycerol‐based polyesters by different catalysts
Authors: Zeng Fenfen , Yang Xin , Li Dexing , Dai Li , Zhang Xinyan , Lv Yin , Wei Zhong 
Published: October 2019

ABSTRACTConvergence of biodegradability and functionality is a major direction of new generation bio‐based materials. Functionalized aliphatic polyesters based on glycerol are synthesized by solvent‐free polycondensation directly. The aim is to prepare linear polyesters with pendant hydroxyl groups along the polymer backbone. The performance of the sustainable biocatalyst Novozyme‐435 (an immobilized form ofCandida antarcticalipase B) and the metal‐based catalyst scandium trifluoromethanesulfonate (also known as scandium triflate) were compared with three organobase catalysts: 1,5,7‐triazabicyclo[4,4,0]dec‐5‐ene, diphenyl hydrogen phosphate, and bis(1,1,2,2,3,3,4,4,4‐nonafluoro‐1‐butanesulfonyl)imide. For the five catalytic systems, the efficiency and selectivity for the incorporation of glycerol were studied, mainly using1H NMR spectroscopies, whereas side reactions, such as different macromolecular architecture of different glyceride groups in polymers, were evaluated using13C NMR. Especially, the biocatalyst Novozyme‐435 succeeded in incorporating glycerol in a selective way with a low reaction temperature, leading to close‐to‐linear polyesters. By using a renewable hydroxyl‐reactive based on polyesters derived from glycerol, it provides a theoretical reference for the synthesis of functional bio‐based materials. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci.2020,137, 48574.
Microcapsulated epoxy resin with nanosilica‐urea formaldehyde composite shell
Authors: Ebrahimnezhad‐Khaljiri Hossein , Eslami‐Farsani Reza , Arbab Chirani Shabnam 
Published: October 2019

ABSTRACTIn this study, the epoxy microcapsules with the nanosilica (0, 1, 2, and 3 wt %)—urea formaldehyde composite shell were synthesized and then characterized by optical microscope (OM), field emission scanning electron microscope (FESEM), Fourier‐transform infrared spectroscopy (FT‐IR), and thermogravimetric analysis. According to the OM analysis, the without nanosilica microcapsules had the semitransparent structures and equal size distributions. Also, the formation of the microcapsule clusters and rupturing microcapsules in the sample containing 3 wt % nanosilica were observed by OM method. The FESEM analysis showed that without nanosilica, microcapsules had a smooth surface, whereas by increasing the percentage of nanosilica up to 2 wt %, the surface roughness was enhanced. It was also observed that on the surface of the microcapsules without nanosilica, two size ranges of the submicrocapsules with the average diameters of 1.12 μm and 208 nm were formed. By adding 1 wt % nanosilica, three size ranges of submicrocapsules were formed, with the average size of 2.63 μm, 824 and 179 nm. The interesting phenomena in the microcapsules containing 2 and 3 wt % nanosilica were the packing submicrocapsules with the polymeric shell and the formation of the microcapsule clusters, respectively. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020, 137, 48580.
Kinetic aspects of concentration of solid nanoparticles at the interface in polystyrene–polyethylene mixtures
Authors: Zaikin Aleksandr , Ahmetov Amir , Centovskij Timofej , Kraus Eduard 
Published: October 2019

ABSTRACTThe effect of several mixing process parameters on the concentration of carbon black particles at the interface between the polymer components in polyethylene–polystyrene mixtures was studied. It was established that the process of particle transport from the polymer phase to the interface happens only under the action of shear deformation, but simultaneously acting shear stresses prevent particle concentration. The nanoparticle accumulation at the interface is determined not only by how favored this process is thermodynamically, but also by the parameters of the mixing process. The filler concentration at the interface is facilitated by a reduction in the shear stress, polymer viscosity, filler particle size, and preliminary injection of filler into the polymer component that is less effective at wetting the filler surface. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020, 137, 48585.
Genomic and transcriptomic analyses of glutathione S‐transferases in an endoparasitoid wasp, Pteromalus puparum
Authors: Xu Gang , Teng Zi‐Wen , Gu Gui‐Xiang , Guo Lei , Wang Fei , Xiao Shan , Wang Jia‐Le , Wang Bei‐Bei , Fang Qi , Wang Fang , Song Qi‐Sheng , Stanley David , Ye Gong‐Yin 
Published: October 2019

AbstractPteromalus puparum is a gregarious pupal endoparasitoid with a wide host range. It deposits eggs into pierid and papilionid butterfly pupae. Glutathione S‐transferases (GSTs) are a family of multifunctional detoxification enzymes that act in xenobiotic metabolism in insects. Insect genome projects have facilitated identification and characterization of GST family members. We identified 20 putative GSTs in the P. puparum genome, including 19 cytosolic and one microsomal. Phylogenetic analysis showed that P. puparum GSTs are clustered into Hymenoptera‐specific branches. Transcriptomic data of embryos, larvae, female pupae, male pupae, female adults, male adults, venom glands, carcass, salivary glands, and ovaries revealed stage‐, sex‐, and tissue‐specific expression patterns of GSTs in P. puparum. This is the most comprehensive study of genome‐wide identification, characterization, and expression profiling of GST family in hymenopterans. Our results provide valuable information for understanding the metabolic adaptation of this wasp.
The diverse niches of megajournals: Specialism within generalism
Authors: Siler Kyle , Larivière Vincent , Sugimoto Cassidy R. 
Published: October 2019

AbstractOver the past decade, megajournals have expanded in popularity and established a legitimate niche in academic publishing. Leveraging advantages of digital publishing, megajournals are characterized by large publication volume, broad interdisciplinary scope, and peer‐review filters that select primarily for scientific soundness as opposed to novelty or originality. These publishing innovations are complementary and competitive vis‐à‐vis traditional journals. We analyze how megajournals (PLOS One, Scientific Reports) are represented in different fields relative to prominent generalist journals (Nature, PNAS, Science) and “quasi‐megajournals” (Nature Communications, PeerJ). Our results show that both megajournals and prominent traditional journals have distinctive niches, despite the similar interdisciplinary scopes of such journals. These niches—defined by publishing volume and disciplinary diversity—are dynamic and varied over the relatively brief histories of the analyzed megajournals. Although the life sciences are the predominant contributor to megajournals, there is variation in the disciplinary composition of different megajournals. The growth trajectories and disciplinary composition of generalist journals—including megajournals—reflect changing knowledge dissemination and reward structures in science.
Applications of Unnatural Amino Acids in Protease Probes
Authors: Maluch Izabela , Czarna Justyna , Drag Marcin 
Published: October 2019

AbstractSince proteases are involved in a wide range of physiological and disease states, the development of novel tools for imaging proteolytic enzyme activity is attracting increasing interest from scientists. Peptide substrates containing proteinogenic amino acids are often the first line of defining enzyme specificity. This Minireview outlines examples of major recent advances in probing proteases using unnatural amino acid residues, which greatly expands the possibilities for designing substrate probes and inhibitory activity‐based probes. This approach already yielded innovative probes that selectively target only one active protease within the group of enzymes exhibiting similar specificity both in cellular assays and in bioimaging research.
Local stabilization of semilinear parabolic system by boundary control
Authors: Si Yuanchao , Xie Chengkang 
Published: October 2019

AbstractThis paper addresses local stabilization of a semilinear parabolic system by boundary control. Under a certain assumption on the nonlinearity of the parabolic equation, a linear boundary feedback control law is applied to control the semilinear system. Based on the operator theories and relations of different norms, locally exponential stabilization of the closed loop system is established. Simulations support the established stability result.
Virtual control with hard constraints
Authors: Al‐Hajjar Ali M. H. , Swei Sean Shan‐Min , Zhu Guoming 
Published: October 2019

AbstractPractical control problems are always subject to plant state and/or input constraints, which make designing an effective controller a challenging task. This paper introduces a novel virtual control approach to handling the presence of hard constraints in control systems by utilizing virtual mechanisms in the form of nonlinear springs and dampers. The augmented virtual mechanisms are to assist in better shaping the closed‐loop responses, especially when operating near the constrained boundary. A linear quadratic regulator based model predictive control method is utilized to develop stabilizing controllers that not only achieve desired system performance, but also meet the imposed hard constraints. The basic idea is to dramatically increase control penalty by way of tuning the spring and damper effect when the constrained state/input response is close to its hard constraint. The proposed method is applied to a balancing ball problem to demonstrate its applicability and effectiveness, and the simulation results validate the proposed concept.
Robust finite‐horizon optimal control of autonomous helicopters in aggressive maneuvering
Authors: Wang Hao , Shi Zongying , Zhong Yisheng 
Published: October 2019

AbstractThere has been an increasing need for autonomous helicopters to have the ability to perform aggressive maneuvers. To achieve this, robust and high performance controllers are required to accurately drive the helicopters. In this paper, the robust compensator (RC) technique is applied to the classic finite‐horizon LQR approach to deal with the uncertainties, including nonlinearities, external disturbances, and other interference. The robust properties of the proposed method are analyzed, and it is proved that the RC can eliminate the effects of the uncertainties as expected. The effectiveness of the proposed method is shown through simulations and real experiments of a prototype helicopter.
Discovery of a role of the novel hepatokine, hepassocin, in obesity
Authors: Huang Ru‐Lai , Li Chung‐Hao , Du Ye‐Fong , Cheng Kai‐Pi , Lin Ching‐Han , Hu Che‐Yuan , Wu Jin Shang , Chang Chih‐Jen , Wu Hung‐Tsung , Ou Horng‐Yih 
Published: October 2019

AbstractObesity is a public health problem that has raised concerns worldwide and is often associated with hepatic steatosis. Hepassocin is a novel hepatokine that causes hepatic steatosis and induces insulin resistance (IR). However, the role of hepassocin in obesity remains obscure. Thus, the aim of this study was to investigate the relationship between hepassocin levels and obesity. In total, 371 subjects who had a normal weight (NW), were overweight, or were obese were enrolled. We found that hepassocin levels in subjects who were overweight (6,705 ± 1,707 pg/ml) or obese (7,335 ± 2,077 pg/ml) were significantly higher than those of subjects with a NW (5,767 ± 1,500 pg/ml) (p < .001, test for trend). A multiple linear regression analysis showed that the body‐mass index, waist circumference, nonalcoholic fatty liver disease, and homeostatic model assessment of IR were independently associated with hepassocin after adjusting for age, sex, high‐sensitivity C‐reactive protein, systolic blood pressure, high‐density lipoprotein‐cholesterol, log triglycerides, alanine transaminase, and the estimated glomerular filtration rate. This study provides evidence that subjects who were overweight or obese had significantly higher hepassocin levels than those with a NW. Hepassocin may be a useful biomarker in managing obesity and its related metabolic dysregulation.
DNA‐Methylierung – das 5. Element
Authors: Kuhlmann Markus 
Published: October 2019

ZusammenfassungDNA‐Methylierung ist eine evolutionär hoch konservierte epigenetische Modifikation. Sie ist wichtig für die genomische Stabilität und kann einen Einfluss auf die Transkriptionsaktivität von Genen haben. In Tieren findet man Cytosinmethylierung im symmetrischen CG‐Sequenzkontext, in Pflanzen kann jedes Cytosin potenziell methyliert werden. Die Methylierung im symmetrischen Kontext ist vererbbar, im asymmetrischen Sequenzkontext muss sie jedes Mal neu „geschrieben“ werden. Der Mechanismus hierfür wird als RNA‐dirigierte DNA‐Methylierung bezeichnet. In Pflanzen erfolgt eine Demethylierung unter Zuhilfenahme des DNA‐Reparaturmechanismus. Eine Änderung im Methylierungsmuster kann zu phänotypischen Veränderungen führen. Man spricht hier von Epimutationen. Als Epigenetik wird der Einfluss von stabil vererbbaren Methylierungszuständen ohne DNA‐Sequenzänderung bezeichnet. Die Änderung der Methylierung ist einerseits vererbbar, andererseits jedoch reversibel. Somit besitzt der Organismus mit diesem „5. Element“ die Möglichkeit, eine Mutation sozusagen auszuprobieren oder abgeschwächte Formen einer veränderten Genexpression zu testen.
Haeckel und das Schöne in der Natur
Authors: Willmann Rainer 
Published: October 2019

ZusammenfassungDer Evolutionsbiologe Ernst Haeckel hat mit seiner ganzheitlichen Weltsicht versucht, Wissenschaft, Philosophie, Ethik und Kunst zusammenzuführen. Im vorliegenden Artikel werden seine Auseinandersetzung mit den Schönheiten der Natur und ihrem Anwendungsbezug dargestellt. Die Kunst solle sich Haeckels Auffassung zu Folge in ihrer Motivfindung vor allem an den Formen des Lebens orientieren. Diese betrachtete er als die höchsten Ausprägungen ästhetischer Erscheinungen. Durch sie solle der Mensch einen Zugang zur Natur gewinnen, zumal der Mensch nicht im Gegensatz zur Natur stehen dürfe. Künstlerisch hoch begabt, hat Haeckel selber durch die zeichnerische Darstellung tausender, meist mikroskopisch kleiner Organismen wesentliche Anregungen für einen solchen Weg gegeben. Zugleich hatte er mit seinen Zeichnungen Einblicke in zuvor weitgehend unbekannte natürliche Strukturen geboten. Auf diese Weise hat er in erheblichem Maße Einfluss auf die Malerei und Bildgestaltung, auf Schmuck‐ und Glaskunst, Architektur, Möbeldesign und Innenraumgestaltung um die Wende des 19. zum 20. Jahrhunderts genommen.
Proteindenaturierung am Beispiel von Milch‐ und Sojaeiweißen
Authors: Högermann Christiane 
Published: October 2019

Experimente mit Cola und „Cola light“ für den Sekundarbereich IIDie Proteinchemie (Bau von Aminosäuren, Polypeptidstrukturen) sowie Ursachen und Formen der Proteindenaturierung stehen in der Regel auf dem Lehrplan des Sekundarbereiches II. Diese irreversible Strukturveränderung hat dahingehend vielfachen Alltagsbezug für die Schüler, als sie in Alltagssituationen häufig präsent ist, so z. B. beim Kochen eines Hühnereis. Der Beitrag stellt eine einfache Versuchsreihe zur Veranschaulichung der dahinterstehenden biochemischen Ursachen vor.
Nachrichten des Verbandes Biologie, Biowissenschaften & Biomedizin in Deutschland
Authors: Wolters Volkmar 
Published: October 2019

Wissenschaft & GesellschaftPositionspapier zur Grundlagenforschung vorgelegtArbeitsgremienNeue Adhoc‐ArbeitsgruppeLandesverbändeBerlin‐BrandenburgNRWThüringenSachsenBundesdelegiertenversammlung