bluuebunny/crossref_metadata_2025 huggingface dataset:
Anti-bacterial Effect of Chrysophyllum albidum Phyto Extract
Authors: Hassan I. A. , Abdulraheem I. , Emun H. O. , Omole O. M.
Published: April 2019

Aims: This study was carried out to investigate the antimicrobial activity of Chrysophyllum albidum leaves extract on selected Gastro-instestinal bacteria such as Salmonella typhimurium, Shigella dysentariae, Vibrio cholera, Escherichia coli and Clostridium perfringens.

Methodology: The leaves were extracted using ethanol, methanol and distilled water; the concentration of the extracts employed were 100 mg/ml, 200 mg/ml, 400 mg/ml and 500 mg/ml respectively; however the   leaf extracts of Chrysophyllum albidum were screened for anti-microbial activity using the in vitro cup-plate method of agar diffusion technique with concentration of 10-5cells/ml of the selected bacteria. Simultaneously, 30 µg tetracycline and 30 µg metronidazole were used as positive control.

Results: The result showed that the most active among them is Tetracycline; followed by ethanolic extract, aqueous extract, methanolic extract and metronidazole extract respectively on the tested bacteria.

Conclusion: This research justifies the traditional use of the leaves of Chrysophyllum albidum for the therapeutic purposes; hence can be commercialized by pharmaceutical outfit; if not for anything but its availability and readily for human consumption.
On the Significance of the Fields’ Energy-Momentum Tensor
Authors: Comay E.
Published: April 2019

This work discusses the significance of the energy-momentum tensor of physical fields of an elementary particle. The Noether theorem shows how this tensor can be derived from the Lagrangian density of a given field. This work proves that the energy-momentum tensor can also be used for a consistency test of a field theory. The results show that the Dirac Lagrangian density of a spin-1/2 massive particle yields consistent results. On the other hand, problems exist with the present structure of quantum electrodynamics, and with quantum fields of massive particles that are described by a second order differential equation. All problematic results are confirmed by an independent analysis.
Comparative analysis of cytokine profiles of glaucomatous tears and aqueous humour reveals potential biomarkers for trabeculectomy complications
Authors: Csősz Éva , Deák Eszter , Tóth Noémi , Traverso Carlo Enrico , Csutak Adrienne , Tőzsér József
Published: April 2019

Glaucoma is a multifactorial neurodegenerative disease that causes impaired vision and, in advanced cases, blindness. The increasing prevalence of glaucoma due to an ageing population has necessitated the identification of suitable biomarkers for the early detection of the disease. Aqueous humour (AH) has been proposed as a source of biomarkers, but it can only be collected using a minor, yet invasive surgical intervention. Tears, however, are constantly available and can be collected any time via noninvasive methods. In order to examine the utility of tear as a surrogate for aqueous humour in biomarker development, we compared the levels of 27 cytokines and chemokines in paired samples of tear and aqueous humour using a Luminex multiplex immunobead‐based technique. Significantly higher levels of cytokines in tear compared to aqueous humour were detected suggesting that tear and aqueous humour are not identical in terms of inflammation response. Furthermore, the levels of IFN‐γ, GM‐CSF and IL‐5 in tear were significantly lower in patients who developed complications after one year, but no statistically significant changes in cytokine levels were observed in aqueous humour. These three molecules may have potential as predictive biomarkers for the appearance of late flap‐related complications of trabeculectomy.
Retracted: Effects of cartoon violence on aggressive thoughts and aggressive behaviors
Authors: Zhang Qian , Cao Yi , Gao JingYa , Yang Xiong , Rost Detlef H. , Cheng Gang , Teng ZhaoJun , Espelage Dorothy L.
Published: April 2019

This article reports on an experiment designed to test whether the cartoon manipulation leads to significant increases in aggressive thoughts and aggressive behaviors among Chinese children (n = 3,000). Results indicated that brief exposure to a violent cartoon triggered higher aggressive thoughts and aggressive behaviors than a nonviolent cartoon. Females displayed higher aggressive thoughts and aggressive behaviors than males in a nonviolent cartoon condition, while males displayed higher aggressive behaviors than females in a violent cartoon condition. Mediation analysis suggested that the effect on aggressive behaviors was mediated by aggressive thoughts. The findings imply that cartoon developers, parents, and teachers should develop cartoons that inhibit children's aggressive thoughts to avoid aggressive behaviors. Females are the key group for the prevention and intervention of aggression in a nonviolent cartoon context, while males are the key group for the prevention and intervention of aggression in a violent cartoon context.
Materials Discovery of Stable and Nontoxic Halide Perovskite Materials for High‐Efficiency Solar Cells
Authors: Jacobs Ryan , Luo Guangfu , Morgan Dane
Published: April 2019

Two critical limitations of organic–inorganic lead halide perovskite materials for solar cells are their poor stability in humid environments and inclusion of toxic lead. In this study, high‐throughput density functional theory (DFT) methods are used to computationally model and screen 1845 halide perovskites in search of new materials without these limitations that are promising for solar cell applications. This study focuses on finding materials that are comprised of nontoxic elements, stable in a humid operating environment, and have an optimal bandgap for one of single junction, tandem Si‐perovskite, or quantum dot–based solar cells. Single junction materials are also screened on predicted single junction photovoltaic (PV) efficiencies exceeding 22.7%, which is the current highest reported PV efficiency for halide perovskites. Generally, these methods qualitatively reproduce the properties of known promising nontoxic halide perovskites that are either experimentally evaluated or predicted from theory. From a set of 1845 materials, 15 materials pass all screening criteria for single junction cell applications, 13 of which are not previously investigated, such as (CH3NH3)0.75Cs0.25SnI3, ((NH2)2CH)Ag0.5Sb0.5Br3, CsMn0.875Fe0.125I3, ((CH3)2NH2)Ag0.5Bi0.5I3, and ((NH2)2CH)0.5Rb0.5SnI3. These materials, together with others predicted in this study, may be promising candidate materials for stable, highly efficient, and nontoxic perovskite‐based solar cells.
3D‐Architected Soft Machines with Topologically Encoded Motion
Authors: Goswami Debkalpa , Liu Shuai , Pal Aniket , Silva Lucas G. , Martinez Ramses V.
Published: April 2019

The limited range of mechanical responses achievable by materials compatible with additive manufacturing hinders the 3D printing of continuum soft robots with programmed motion. This paper describes the rapid design and fabrication of low‐density, 3D‐architected soft machines (ASMs) by combining Voronoi tessellation and additive manufacturing. On tendon‐based actuation, ASMs deform according to the topologically encoded buckling of their structure to produce a wide range of motions (contraction, twisting, bending, and cyclic motion). ASMs exhibiting densities as low as 0.094 g cm−3 (≈8% of bulk polymer) can be rapidly built by the stereolithographic 3D printing of flexible photopolymers or the injection molding of elastomers. The buckling of ASMs can be programmed by inducing gradients in the thickness of their flexible beams or by the localized enlargement of the Voronoi cells to generate complex motions such as multi‐finger gripping or quadrupedal locomotion. The topological architecture of these low‐density soft robots confers them with the stiffness necessary to recover their original shape even after ultrahigh compression (400%) and extension (500%). ASMs expand the range of mechanical properties currently achievable by 3D printed or molded materials to enable the fabrication of soft machines with auxetic mechanical metamaterial properties.
Phase‐Engineered Synthesis of Ultrathin Hexagonal and Monoclinic GaTe Flakes and Phase Transition Study
Authors: Yu Yiwei , Ran Meng , Zhou Shasha , Wang Renyan , Zhou Fengya , Li Huiqiao , Gan Lin , Zhu Mingqiang , Zhai Tianyou
Published: April 2019

GaTe is an important III–VI semiconductor with direct bandgap; thus, it holds great potential in the field of optoelectronics. Although it is known that GaTe can exist both in monoclinic and hexagonal phases, current studies are still exclusively restricted to the monoclinic phase of two dimensional (2D) GaTe owing to the difficulty in the fabrication of 2D hexagonal GaTe. Both monoclinic and hexagonal GaTe are demonstrated in this work, which can be selectively synthesized via a physical vapor deposition method, under precisely controlled growth temperatures. The pristine Raman and non‐linear optical properties of hexagonal GaTe has been systematically explored for the first time; moreover, a novel selected‐area phase transition from hexagonal to monoclinic of GeTe has been achieved via fs‐laser irradiation. This work may pave the way for widely use of 2D GaTe in various fields in future.
Conductive CoOOH as Carbon‐Free Sulfur Immobilizer to Fabricate Sulfur‐Based Composite for Lithium–Sulfur Battery
Authors: Wang Zhen‐Yu , Wang Lu , Liu Sheng , Li Guo‐Ran , Gao Xue‐Ping
Published: April 2019

Lithium–sulfur battery is recognized as one of the most promising energy storage devices, while the application and commercialization are severely hindered by both the practical gravimetric and volumetric energy densities due to the low sulfur content and tap density with lightweight and nonpolar porous carbon materials as sulfur host. Herein, for the first time, conductive CoOOH sheets are introduced as carbon‐free sulfur immobilizer to fabricate sulfur‐based composite as cathode for lithium–sulfur battery. CoOOH sheet is not only a good sulfur‐loading matrix with high electron conductivity, but also exhibits outstanding electrocatalytic activity for the conversion of soluble lithium polysulfide. With an ultrahigh sulfur content of 91.8 wt% and a tap density of 1.26 g cm−3, the sulfur/CoOOH composite delivers high gravimetric capacity and volumetric capacity of 1199.4 mAh g−1‐composite and 1511.3 mAh cm−3 at 0.1C rate, respectively. Meanwhile, the sulfur‐based composite presents satisfactory cycle stability with a slow capacity decay rate of 0.09% per cycle within 500 cycles at 1C rate, thanks to the strong interaction between CoOOH and soluble polysulfides. This work provides a new strategy to realize the combination of gravimetric energy density, volumetric energy density, and good electrochemical performance of lithium–sulfur battery.
Bioprinting a Synthetic Smectic Clay for Orthopedic Applications
Authors: Afewerki Samson , Magalhães Leila S. S. M. , Silva André D. R. , Stocco Thiago D. , Silva Filho Edson C. , Marciano Fernanda R. , Lobo Anderson O.
Published: April 2019

Bioprinting technology has emerged as an important approach to bone and cartilage tissue engineering applications, because it allows the printing of scaffolds loaded with various components, such as cells, growth factors, or drugs. In this context, the bone has a very complex architecture containing highly vascularized and calcified tissues, while cartilage is avascular and has low cellularity and few nutrients. Owing to this complexity, the repair and regeneration of these tissues are highly challenging. Identification of the appropriate biomaterial and fabrication technologies can provide sustainable solutions to this challenge. Here, nanosized Laponite® (Laponite is a trademark of the company BYK Additives Ltd.) has shown to be a promising material due to its unique properties such as excellent biocompatibility, facile gel formation, shear‐thinning property (reversible physical crosslinking), high specific surface area, degrade into nontoxic products, and with osteoinductive properties. Even though Laponite and Laponite‐based composite for 3D bioprinting application are considered as soft gels, they may therefore not be thought exhibiting sufficient mechanical strength for orthopedic applications. However, through the merging with suitable composite and, also by incorporation of crosslinking step, desired mechanical strength for orthopedic application can be obtained. In this review, recent advances and future perspective of bioprinting Laponite and Laponite composites for orthopedic applications are highlighted.
Interfacial Electronic Structure Modulation of NiTe Nanoarrays with NiS Nanodots Facilitates Electrocatalytic Oxygen Evolution
Authors: Xue Ziqian , Li Xia , Liu Qinglin , Cai Mengke , Liu Kang , Liu Min , Ke Zhuofeng , Liu Xialin , Li Guangqin
Published: April 2019

Interface engineering has been recognized as one of the most promising strategies for regulating the physical and chemical properties of materials. However, constructing well‐defined nanointerfaces with efficient oxygen evolution reaction (OER) still remains a challenge. Herein, cross columnar NiTe nanoarrays supported on nickel foam are prepared. Subsequently, NiTe/NiS nanointerfaces are constructed by an ion‐exchange process. Importantly, the electrocatalytic performance for the OER can be facilitated by coupling NiTe and NiS. As a result, NiTe/NiS shows excellent OER activity with an ultralow overpotential of only 257 mV at a current density of 100 mA cm−2, and a Tafel slope of 49 mV dec−1 in 1.0 m KOH. The calculated and experimental results reveal that the strong electron interaction on nanointerfaces induces electronic structure modulation, which optimizes the binding energy of *OOH intermediates, thus improving the OER performance.
Giant Enhancements of Perpendicular Magnetic Anisotropy and Spin‐Orbit Torque by a MoS2 Layer
Authors: Xie Qidong , Lin Weinan , Yang Baishun , Shu Xinyu , Chen Shaohai , Liu Liang , Yu Xiaojiang , Breese Mark B. H. , Zhou Tiejun , Yang Ming , Zhang Zheng , Wang Shijie , Yang Hongxin , Chai Jianwei , Han Xiufeng , Chen Jingsheng
Published: April 2019

2D transition metal dichalcogenides have attracted much attention in the field of spintronics due to their rich spin‐dependent properties. The promise of highly compact and low‐energy‐consumption spin‐orbit torque (SOT) devices motivates the search for structures and materials that can satisfy the requirements of giant perpendicular magnetic anisotropy (PMA) and large SOT simultaneously in SOT‐based magnetic memory. Here, it is demonstrated that PMA and SOT in a heavy metal/transition metal ferromagnet structure, Pt/[Co/Ni]2, can be greatly enhanced by introducing a molybdenum disulfide (MoS2) underlayer. According to first‐principles calculation and X‐ray absorption spectroscopy (XAS), the enhancement of the PMA is ascribed to the modification of the orbital hybridization at the interface of Pt/Co due to MoS2. The enhancement of SOT by the role played by MoS2 is explained, which is strongly supported by the identical behavior of SOT and PMA as a function of Pt thickness. This work provides new possibilities to integrate 2D materials into promising spintronics devices.
Dielectric Selection for Solution‐Processed High‐Mobility TIPS‐Pentacene Microwire Field‐Effect Transistors
Authors: Wang Shuya , Zhou Shujun , Tong Yanhong , Song Zhiqi , Wang Haiting , Tang Qingxin , Zhao Xiaoli , Liu Yichun
Published: April 2019

The dielectric effect on the mobility of the solution‐processed organic field‐effect transistors (OFETs) remains unknown. A major challenge is that most of the solution‐processed OFETs are obtained on hydrophilic dielectrics, while most of the commonly used dielectrics for high‐mobility OFETs are hydrophobic. In this work, by selecting a preferred solvent to ensure the good wettability of 6,13‐bis(triisopropylsilylethynyl)‐pentacene (TIPS‐pentacene) solution on both hydrophobic and hydrophilic dielectrics, the highly ordered TIPS‐pentacene single‐crystal microwire arrays are in situ grown on the hydrophobic and hydrophilic dielectrics via a solution‐processed method, and the dielectric effect on the mobility of the solution‐processed TIPS‐pentacene OFETs is investigated. The highest mobility on the divinyltetramethyldisiloxane‐bis(benzocyclobutene) (BCB)/SiO2 dielectric is ascribed to the matching of both the polar and dispersive components of surface energy between dielectric and semiconductor. This work powerfully confirms the direct effect of the dielectric properties on mobility, and provides a new method to select the optimized dielectric for solution‐processed high‐mobility OFETs.
A Sulfone‐Containing Imidazolium‐Based Brønsted Acid Ionic Liquid Catalyst Enables Replacing Dipolar Aprotic Solvents with Butyl Acetate
Authors: El‐Harairy Ahmed , Yiliqi  , Lai Bingbing , Vaccaro Luigi , Li Minghao , Gu Yanlong
Published: April 2019

Replacing dipolar and aprotic solvents with environmentally benign media has emerged as a new facet of green chemistry. In this paper, a sulfone‐containing imidazolium‐based Brønsted acid ionic liquid was prepared and used as a recyclable acid catalyst. The ionic liquid catalyst enables the use of an industrially acceptable and environmentally benign solvent, butyl acetate, as the reaction medium. The ionic liquid/butyl acetate biphasic system was successfully utilized in many organic reactions, which generally relied heavily on dipolar and aprotic solvents.

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Reversible Modification of Ferromagnetism through Electrically Controlled Morphology
Authors: Vinai Giovanni , Motti Federico , Bonanni Valentina , Petrov Aleksander Yu. , Benedetti Stefania , Rinaldi Christian , Stella Mattia , Cassese Damiano , Prato Stefano , Cantoni Matteo , Rossi Giorgio , Panaccione Giancarlo , Torelli Piero
Published: April 2019

Converse magnetoelectric coupling in artificial multiferroics is generally modeled through three possible mechanisms: charge transfer, strain mediated effects or ion migration. Here the role played by electrically controlled morphological modifications on the ferromagnetic response of a multiferroic heterostructure, specifically FexMn1−x ferromagnetic films on piezoferroelectric PMN‐PT [001] substrates, is discussed. The substrates present, in correspondence to electrical switching, fully reversible morphological changes at the surface, to which correspond reproducible modifications of the ferromagnetic response of the FexMn1−x films. Topographic analysis by atomic force microscopy shows the formation of surface cracks (up to 100 nm in height) upon application of a sufficiently high positive electric field (up to 6 kV cm−1). The cracks disappear after application of negative electric field of the same magnitude. Correspondingly, in operando X‐ray magnetic circular dichroic spectroscopy at Fe edge in FexMn1−x layers and micro‐MOKE measurements show local variations in the intensity of the dichroic signal and in the magnetic anisotropy as a function of the electrically driven morphological state. This morphologic parameter, rarely explored in literature, directly affects the ferromagnetic response of the system. Its proof of electrically reversible modification of the magnetic response adds a new possibility in the design of electrically controlled magnetic devices.
Realizing Ultrafast Oxygen Evolution by Introducing Proton Acceptor into Perovskites
Authors: She Sixuan , Zhu Yinlong , Chen Yubo , Lu Qian , Zhou Wei , Shao Zongping
Published: April 2019

The oxygen evolution reaction (OER) is of prime importance in multiple energy storage devices. Perovskite oxides involving lattice‐oxygen oxidation are generally regarded as highly active OER catalysts, but the deprotonation of surface‐bound intermediates limit the further activity improvement. Here, it is shown that this kinetic limitation can be removed by introducing Sr3B2O6 (SB) which activates a proton‐acceptor functionality to boost OER activity. As a proof‐of‐concept example, an experimental validation is conducted on the extraordinary OER performance of a Sr(Co0.8Fe0.2)0.7B0.3O3−δ (SCFB‐0.3) hybrid catalyst, made using Sr0.8Co0.8Fe0.2O3−δ as active component and SB as a proton acceptor. This smart hybrid exhibits an exceptionally ultrahigh OER activity with an extremely low overpotential of 340 mV in 0.1 m KOH and 240 mV in 1 m KOH required for 10 mA cm−2 which is the top‐level catalytic activity among metal oxides reported so far, while maintaining excellent durability. The correlation of pH and activity study reveals that this enhanced activity mainly originates from the improved interfacial proton transfer. Such a strategy further demonstrated to be universal, which can be applied to enhance the OER activity of other high covalent oxides with close O 2p‐band centers relative to Fermi energy.
A parametric study of the techno‐economics of direct CO2 air capture systems using solid adsorbents
Authors: Sinha Anshuman , Realff Matthew J.
Published: April 2019

Direct air capture (DAC) can help in reduction of atmospheric CO2 levels by capturing CO2 from disperse emission sources. We analyze DAC process through solid adsorbent and perform comprehensive energy and techno‐economic analysis for different parametric scenarios. The parameters are varied such that it reflects list of possible cases of DAC solid adsorbent systems ranging from worst case to best case situations. A mid‐range estimate has also been analyzed which considers the parameter values feasible with the current state of the art. The modeling results for the mid‐range estimate indicate that the cost of DAC lies between $86 and 221 per tCO2, the thermal energy range varies from 3.4 to 4.8 GJ per tCO2 captured and the electrical energy range varies from 0.55 to 1.12 GJ per tCO2 captured. For the best and worst case scenarios, the cost of DAC ranges from $14 to 1,065 per tCO2, thermal energy ranges from 1.85 to 19.30 per tCO2 captured and the electrical energy ranges from 0.08 to 3.79 GJ per tCO2 captured. Flux and intensity estimates have been performed which shows higher flux and lower intensity of DAC process as compared to a tropical tree.
Multiscale model based design of an energy‐intensified novel adsorptive reactor process for the water gas shift reaction
Authors: Karagöz Seçgin , Chen Huanhao , Cao Mingyuan , Tsotsis Theodore T. , Manousiouthakis Vasilios I.
Published: April 2019

In this work, an adsorptive reactor (AR) process is considered that can energetically intensify the water gas shift reaction (WGSR). To best understand AR process behavior, a multiscale, dynamic, process model is developed. This multiscale model enables the quantification of catalyst and adsorbent effectiveness factors within the reactor environment, obliviating the commonly employed assumption that these factors are constant. Simulations of the AR's alternating adsorption‐reaction/desorption operation, using the proposed model, illustrate rapid convergence to a long‐term periodic solution. The obtained simulation results quantify the influence of key operating conditions and design parameters (e.g., reactor temperature/pressure, Wcat/FCO, Wad/FCO, FH2O/FCO ratios, and pellet size) on the AR's behavior. They also demonstrate, for pellet diameters used at the industrial scale, significant temporal and axial variation of the catalyst/adsorbent pellet effectiveness factors. Finally, the energetic intensification benefits of the proposed AR process over conventional WGSR packed‐bed reactors are quantified.
Copper‐Mediated Direct and Selective C−H Thiolation of Quinazolinones
Authors: Sarkar Writhabrata , Mishra Aniket , Bhowmik Arup , Deb Indubhusan
Published: April 2019

Direct thiolation of quinazolinones by selective cleavage of a relatively inert C−H bond, mediated by earth‐abundant copper and guided by a pyridine or pyrimidine moiety, has been achieved under operationally simple conditions. The devised protocol does not require any toxic or reactive reagents and provides direct access to a broad spectrum of pharmaceutically relevant thioquinazolinones.
Eine intrinsische Hydrophobieskala für Aminosäuren und ihre Anwendung auf fluorierte Verbindungen
Authors: Hoffmann Waldemar , Langenhan Jennifer , Huhmann Susanne , Moschner Johann , Chang Rayoon , Accorsi Matteo , Seo Jongcheol , Rademann Jörg , Meijer Gerard , Koksch Beate , Bowers Michael T. , von Helden Gert , Pagel Kevin
Published: April 2019

Es existieren über 100 Hydrophobieskalen für Aminosäuren, die auf unterschiedlichen Ansätzen basieren und einheitlich in kondensierter Phase ermittelt werden. Ein Vergleich der Hydrophobiewerte aus verschiedenen Methoden und die Ermittlung ihrer relativen Rangfolge sind jedoch anspruchsvoll, da die Wechselwirkungen zwischen der Umgebung und der Aminosäure in jeder Methode spezifisch sind. Hier überwinden wir diese Einschränkung, indem wir die Eigenschaften von Aminosäuren in der Reinraumumgebung der Gasphase untersuchen. In der Gasphase bleiben standardmäßig entropische Beiträge des hydrophoben Effektes aus, und nur die Polarität der Seitenkette ist für die Selbstorganisation entscheidend. Dies ermöglicht die Ableitung einer neuartigen Hydrophobieskala, die ausschließlich auf der Interaktion einzelner Aminosäureeinheiten innerhalb des Clusters basiert und somit die Eigenschaften der Seitenketten besser abbildet. Dieses Prinzip kann für die Klassifizierung von nicht‐natürlichen Derivaten angewendet werden, wie hier für fluorierte Aminosäurevarianten gezeigt ist.
Highly Enantioselective Synthesis of Fused Tri‐ and Tetrasubstituted Aziridines: aza‐Darzens Reaction of Cyclic Imines with α‐Halogenated Ketones Catalyzed by Bifunctional Phosphonium Salt
Authors: Pan Jianke , Wu Jia‐Hong , Zhang Hongkui , Ren Xiaoyu , Tan Jian‐Ping , Zhu Lixiang , Zhang Hong‐Su , Jiang Chunhui , Wang Tianli
Published: April 2019

The first enantioselective aza‐Darzens reaction of cyclic imines with α‐halogenated ketones was realized under mild reaction conditions by using amino‐acid‐derived bifunctional phosphonium salts as phase‐transfer promoters. A variety of structurally dense tri‐ and tetrasubstituted aziridine derivatives, containing benzofused heterocycles as well as spiro‐structures, were readily synthesized in high yields with excellent diastereo‐ and enantioselectivities (up to >20:1 d.r. and >99.9 % ee). The highly functionalized aziridine products could be easily transformed into different classes of biologically active compounds.
Synthesis of CuS@CoS2 Double‐Shelled Nanoboxes with Enhanced Sodium Storage Properties
Authors: Fang Yongjin , Guan Bu Yuan , Luan Deyan , Lou Xiong Wen (David)
Published: April 2019

Metal sulfides have received considerable attention for efficient sodium storage owing to their high capacity and decent redox reversibility. However, the poor rate capability and fast capacity decay greatly hinder their practical application in sodium‐ion batteries. Herein, an elegant multi‐step templating strategy has been developed to rationally synthesize hierarchical double‐shelled nanoboxes with the CoS2 nanosheet‐constructed outer shell supported on the CuS inner shell. Their structure and composition enable these hierarchical CuS@CoS2 nanoboxes to show boosted electrochemical properties with high capacity, outstanding rate capability, and long cycle life.
A Concise Total Synthesis of (−)‐Himalensine A
Authors: Chen Yuye , Hu Jingping , Guo Lian‐Dong , Zhong Weihe , Ning Chengqing , Xu Jing
Published: April 2019

The daphniphyllum alkaloids are a structurally fascinating and remarkably diverse family of natural products. General strategies for the chemical synthesis of their challenging architectures are highly desirable for efficiently accessing these intriguing alkaloids and addressing their pharmaceutical potential. Herein, a concise strategy designed to provide general and diversifiable access to various daphniphyllum alkaloids is described and utilized in the asymmetric synthesis of (−)‐himalensine A, which was accomplished in 14 steps. Key features of this strategy include a Cu‐catalyzed nitrile hydration, a Heck reaction to construct the challenging 2‐azabicyclo[3.3.1]nonane motif, a Meinwald rearrangement reaction, six, pot‐economic reactions, and the minimal use of protecting groups, which significantly improved the overall synthetic efficiency.
Bullet‐like Cu9S5 Hollow Particles Coated with Nitrogen‐Doped Carbon for Sodium‐Ion Batteries
Authors: Fang Yongjin , Yu Xin‐Yao , Lou Xiong Wen (David)
Published: April 2019

Metal sulfides with excellent redox reversibility and high capacity are very promising electrode materials for sodium‐ion batteries. However, their practical application is still hindered by the poor rate capability and limited cycle life. Herein, a template‐based strategy is developed to synthesize nitrogen‐doped carbon‐coated Cu9S5 bullet‐like hollow particles starting from bullet‐like ZnO particles. With the structural and compositional advantages, these unique nitrogen‐doped carbon‐coated Cu9S5 bullet‐like hollow particles manifest excellent sodium storage properties with superior rate capability and ultra‐stable cycling performance.
Structural Evolution and Effect of the Neighboring Cation on the Photoluminescence of Sr(LiAl3)1−x(SiMg3)xN4:Eu2+ Phosphors
Authors: Fang Mu‐Huai , Mahlik Sebastian , Lazarowska Agata , Grinberg Marek , Molokeev Maxim S. , Sheu Hwo‐Shuenn , Lee Jyh‐Fu , Liu Ru‐Shi
Published: April 2019

In this study, a series of Sr(LiAl3)1−x(SiMg3)xN4:Eu2+ (SLA‐SSM) phosphors were synthesized by a solid‐solution process. The emission peak maxima of SLA‐SSM range from 615 nm to 680 nm, which indicates structural differences in these materials. 7Li solid‐state NMR spectroscopy was utilized to distinguish between the Li(1)N4 and Li(2)N4 tetrahedra in SLA‐SSM. Differences in the coordination environments of the two Sr sites were found which explain the unexpected luminescent properties. Three discernible morphologies were detected by scanning electron microscopy. Temperature‐dependent photoluminescence and decay times were used to understand the diverse environments of europium ions in the two strontium sites Sr1 and Sr2, which also support the NMR analysis. Moreover, X‐ray absorption near‐edge structure studies reveal that the Eu2+ concentration in SLA‐SSM is much higher than that in in SrLiAl3N4:Eu2+ and SrSiMg3N4:Eu2+ phosphors. Finally, an overall mechanism was proposed to explain the how the change in photoluminescence is controlled by the size of the coordinated cation.
Design of Photostable, Activatable Near‐Infrared Photoacoustic Probes Using Tautomeric Benziphthalocyanine as a Platform
Authors: Toriumi Naoyuki , Asano Norihito , Ikeno Takayuki , Muranaka Atsuya , Hanaoka Kenjiro , Urano Yasuteru , Uchiyama Masanobu
Published: April 2019

Near‐infrared (NIR) imaging techniques have attracted significant attention for biological and medicinal applications due to the ability of NIR to penetrate deeply into tissues. However, there are very few stable, activatable molecular probes that can utilize NIR light in the wavelength range beyond 800 nm. Herein, we report a new activatable NIR system for photoacoustic imaging based on tautomeric benziphthalocyanines (BPcs). We found that the existence of a free hydroxyl group is crucial for NIR absorption of BPcs. Synthesized water‐soluble hydroxy BPcs exhibited high photostability and no fluorescence, which are desirable features for photoacoustic imaging. We synthesized BPcs in which the free hydroxyl group was masked by an esterase‐labile or an H2O2‐labile group. The photoacoustic signals of these hydroxy‐masked BPcs were increased upon NIR excitation at 880 nm in the presence of esterase or H2O2, respectively. These are rare examples of activatable probes utilizing NIR light at around 900 nm.
Activation and Spillover of Hydrogen on Sub‐1 nm Palladium Nanoclusters Confined within Sodalite Zeolite for the Semi‐Hydrogenation of Alkynes
Authors: Wang Shuai , Zhao Zhi‐Jian , Chang Xin , Zhao Jiubing , Tian Hao , Yang Chengsheng , Li Mingrun , Fu Qiang , Mu Rentao , Gong Jinlong
Published: April 2019

The search for efficient nontoxic catalysts able to perform industrial hydrogenations is a topic of interest, with relevance to many catalytic processes. Herein, we describe a mechanistic phenomenon for the activation and spillover of hydrogen for remarkable selectivity in the semi‐hydrogenation of acetylene over sub‐1 nm Pd nanoclusters confined within sodalite (SOD) zeolite (Pd@SOD). Specifically, hydrogen is dissociated on the Pd nanoclusters to form hydrogen species (i.e., hydrogen atoms and hydroxyl groups) that spill over the SOD surfaces. The design and utilization of the small‐pore zeolite SOD (six‐membered rings with 0.28×0.28 nm channels) is crucial as it only allows H2 diffusion into the channels to reach the encapsulated Pd nanoclusters and thus avoids over‐hydrogenation to form ethane. Pd@SOD exhibits an ethylene selectivity of over 94.5 %, while that of conventional Pd/SOD is approximately 21.5 %.
An Intrinsic Hydrophobicity Scale for Amino Acids and Its Application to Fluorinated Compounds
Authors: Hoffmann Waldemar , Langenhan Jennifer , Huhmann Susanne , Moschner Johann , Chang Rayoon , Accorsi Matteo , Seo Jongcheol , Rademann Jörg , Meijer Gerard , Koksch Beate , Bowers Michael T. , von Helden Gert , Pagel Kevin
Published: April 2019

More than 100 hydrophobicity scales have been introduced, with each being based on a distinct condensed‐phase approach. However, a comparison of the hydrophobicity values gained from different techniques, and their relative ranking, is not straightforward, as the interactions between the environment and the amino acid are unique to each method. Here, we overcome this limitation by studying the properties of amino acids in the clean‐room environment of the gas phase. In the gas phase, entropic contributions from the hydrophobic effect are by default absent and only the polarity of the side chain dictates the self‐assembly. This allows for the derivation of a novel hydrophobicity scale, which is based solely on the interaction between individual amino acid units within the cluster and thus more accurately reflects the intrinsic nature of a side chain. This principle can be further applied to classify non‐natural derivatives, as shown here for fluorinated amino acid variants.
Structural Studies Reveal Enantiospecific Recognition of a DNA G‐Quadruplex by a Ruthenium Polypyridyl Complex
Authors: McQuaid Kane , Abell Holly , Gurung Sarah P. , Allan David R. , Winter Graeme , Sorensen Thomas , Cardin David J. , Brazier John A. , Cardin Christine J. , Hall James P.
Published: April 2019

By using X‐ray crystallography, we show that the complexes Λ/Δ‐[Ru(TAP)2(11‐CN‐dppz)]2+ (TAP=1,4,5,8‐tetraazaphenanthrene, dppz=dipyridophenazine) bind DNA G‐quadruplex in an enantiospecific manner that parallels the specificity of these complexes with duplex DNA. The Λ complex crystallises with the normally parallel stranded d(TAGGGTTA) tetraplex to give the first such antiparallel strand assembly in which syn‐guanosine is adjacent to the complex at the 5′ end of the quadruplex core. SRCD measurements confirm that the same conformational switch occurs in solution. The Δ enantiomer, by contrast, is present in the structure but stacked at the ends of the assembly. In addition, we report the structure of Λ‐[Ru(phen)2(11‐CN‐dppz)]2+ bound to d(TCGGCGCCGA), a duplex‐forming sequence, and use both structural models to provide insight into the motif‐specific luminescence response of the isostructural phen analogue enantiomers.
Orthogonal Halogen‐Bonding‐Driven 3D Supramolecular Assembly of Right‐Handed Synthetic Helical Peptides
Authors: Teng Peng , Gray Geoffrey M. , Zheng Mengmeng , Singh Sylvia , Li Xiaopeng , Wojtas Lukasz , van der Vaart Arjan , Cai Jianfeng
Published: April 2019

Peptide‐mediated self‐assembly is a prevalent method for creating highly ordered supramolecular architectures. Herein, we report the first example of orthogonal C−X⋅⋅⋅X−C/C−X⋅⋅⋅π halogen bonding and hydrogen bonding driven crystalline architectures based on synthetic helical peptides bearing hybrids of l‐sulfono‐γ‐AApeptides and natural amino acids. The combination of halogen bonding, intra‐/intermolecular hydrogen bonding, and intermolecular hydrophobic interactions enabled novel 3D supramolecular assembly. The orthogonal halogen bonding in the supramolecular architecture exerts a novel mechanism for the self‐assembly of synthetic peptide foldamers and gives new insights into molecular recognition, supramolecular design, and rational design of biomimetic structures.
Syntheses of intrinsically flame‐retardant polyamide 6 fibers and fabrics
Authors: Mourgas Georgios , Giebel Elisabeth , Schneck Tanja , Unold Joerg , Buchmeiser Michael R.
Published: April 2019

In this study, flame‐retarded polyamide 6 (FR‐PA6) was prepared via the direct co‐condensation of ε‐caprolactam with two different organophosphorus compounds in a typical melt‐polymerization process. Polymer microstructures, especially the incorporation of the phosphorus‐containing comonomers, as well as the thermal and physical properties of the resulting copolyamides have been studied in detail. The phosphorus‐modified PAs have a P‐content of 0.10–0.30 wt %, possess high relative viscosities of 2.2–2.4 and good thermal stability. FR‐PA6 multifilaments were prepared by melt spinning and show tensile strengths up to 40 cN/tex and tenacities up to 0.5 GPa. Knitted fabrics of FR‐PA6 exhibit high limiting oxygen index values around 35%. Due to the very low phosphorus content, there is no impairment of the material properties of PA6. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci.2019,136, 47829.
A coefficient of determination (R2) for generalized linear mixed models
Authors: Piepho Hans‐Peter
Published: April 2019

Extensions of linear models are very commonly used in the analysis of biological data. Whereas goodness of fit measures such as the coefficient of determination (R2) or the adjusted R2 are well established for linear models, it is not obvious how such measures should be defined for generalized linear and mixed models. There are by now several proposals but no consensus has yet emerged as to the best unified approach in these settings. In particular, it is an open question how to best account for heteroscedasticity and for covariance among observations present in residual error or induced by random effects. This paper proposes a new approach that addresses this issue and is universally applicable for arbitrary variance‐covariance structures including spatial models and repeated measures. It is exemplified using three biological examples.
Minimizing the Influence of Fluorescent Tags on IgG Partition in PEG–Salt Aqueous Two‐Phase Systems for Rapid Screening Applications
Authors: São Pedro Mariana N. , Azevedo Ana M. , Aires‐Barros Maria R. , Soares Ruben R. G.
Published: April 2019

Aqueous two‐phase extraction (ATPE) has been showing significant potential in the biopharmaceutical industry, allowing the selective separation of high‐value proteins directly from unclarified cell culture supernatants. In this context, effective high‐throughput screening tools are critical to perform a rapid empirical optimization of operating conditions. In particular, microfluidic ATPE screening devices, coupled with fluorescence microscopy to continuously monitor the partition of fluorophore‐labeled proteins, have been recently demonstrated to provide short diffusion distances and rapid partition, using minimal reagent volumes. Nevertheless, the currently overlooked influence of the labeling procedure on partition must be carefully evaluated to validate the extrapolation of results to the unlabeled molecule. Here, three fluorophores with different global charge and reactivity selected to label immunoglobulin G (IgG) at degrees of labeling (DoL) ranging from 0.5 to 7.6. Labeling with BODIPY FL maleimide (DoL = 0.5), combined with tris(2‐carboxyethyl) phosphine (TCEP) to generate free thiol groups, is the most promising strategy to minimize the influence of the fluorophore on partition. In particular, the partition coefficient (Kp) measured in polyethylene glycol (PEG) 3350–phosphate systems with and without the addition of NaCl using microtubes (batch) or microfluidic devices (continuous) is comparable to those quantified for the native protein.
Collagen type I and hyaluronic acid based hybrid scaffolds for heart valve tissue engineering
Authors: Nazir Rabia , Bruyneel Arne , Carr Carolyn , Czernuszka Jan
Published: April 2019

Tissue engineers have achieved limited success so far in designing an ideal scaffold for aortic valve; scaffolds lack in mechanical compatibility, appropriate degradation rate, and microstructural similarity. This paper, therefore, has demonstrated a carbodiimide‐based sequential crosslinking technique to prepare aortic valve extracellular matrix mimicking (ECM) hybrid scaffolds from collagen type I and hyaluronic acid (HA), the building blocks of heart valve ECM, with tailorable crosslinking densities. Swelling studies revealed that crosslinking densities of parent networks increased with increasing the concentration of the crosslinking agents whereas crosslinking densities of hybrid scaffolds averaged from those of parent collagen and HA networks. Hybrid scaffolds also offered a wide range of pore size (66‐126 μm) which fulfilled the criteria for valvular tissue regeneration. Scanning electron microscopy and images of Alcian blue‐Periodic acid Schiff stained samples suggested that our crosslinking technique yielded an ECM mimicking microstructure with interlaced bands of collagen and HA in the hybrid scaffolds. The mutually reinforcing networks of collagen and HA also resulted in increased bending moduli up to 1660 kPa which spanned the range of natural aortic valves. Cardio sphere‐derived cells (CDCs) from rat hearts showed that crosslinking density affected the available cell attachment sites on the surface of the scaffold. Increased bending moduli of CDCs seeded scaffolds up to two folds (2‐6 kPa) as compared to the non‐seeded scaffolds (1 kPa) suggested that an increase in crosslinking density of the scaffolds could not only increase the in vitro bending modulus but also prevented its disintegration in the cell culture medium.
Development and validation of a sensitive liquid‐chromatography tandem mass spectrometry assay for mycophenolic acid and metabolites in HepaRG cell culture: Characterization of metabolism interactions between p‐cresol and mycophenolic acid
Authors: Rong Yan , Kiang Tony K.L.
Published: April 2019

Mycophenolic acid (MPA), a frequently used immunosuppressant, exhibits large inter‐patient pharmacokinetic variability. This study (a) developed and validated a sensitive liquid chromatography–tandem mass spectrometry (LC–MS/MS) assay for MPA and metabolites [MPA glucuronide (MPAG) and acyl‐glucuronide (AcMPAG)] in the culture medium of HepaRG cells; and (b) characterized the metabolism interaction between MPA and p‐cresol (a common uremic toxin) in this in vitro model as a potential mechanism of pharmacokinetic variability. Chromatographic separation was achieved with a C18 column (4.6 × 250 mm,5 μm) using a gradient elution with water and methanol (with 0.1% formic acid and 2 mm ammonium acetate). A dual ion source ionization mode with positive multiple reaction monitoring was utilized. Multiple reaction monitoring mass transitions (m/z) were: MPA (320.95 → 207.05), MPAG (514.10 → 303.20) and AcMPAG (514.10 → 207.05). MPA‐d3 (323.95 → 210.15) and MPAG‐d3 (517.00 → 306.10) were utilized as internal standards. The calibration curves were linear from 0.00467 to 3.2 μg/mL for MPA/MPAG and from 0.00467 to 0.1 μg/mL for AcMPAG. The assay was validated based on industry standards. p‐Cresol inhibited MPA glucuronidation (IC50 ≈ 55 μm) and increased MPA concentration (up to >2‐fold) at physiologically relevant substrate‐inhibitor concentrations (n = 3). Our findings suggested that fluctuations in p‐cresol concentrations might be in part responsible for the large pharmacokinetic variability observed for MPA in the clinic.
Implementing natural capital credit risk assessment in agricultural lending
Authors: Ascui Francisco , Cojoianu Theodor F.
Published: April 2019

Agriculture has critical impacts and dependencies on natural capital, and agricultural lenders are therefore exposed to natural capital credit risk through their loans to farmers. Currently, however, lenders lack any detailed guidance for assessing natural capital credit risk in agriculture and are challenged by the fact that the relevant material risks vary considerably by agricultural sector and geography. This paper develops a natural capital credit risk assessment framework based on a bottom‐up review of the material risks associated with natural capital impacts and dependencies for Australian beef production. It demonstrates that implementing natural capital credit risk assessment is feasible in agricultural lending, using a combination of quantitative and qualitative inputs. Implementation challenges include the complexity and interconnectedness of natural capital processes, data availability and cost, spatial data analytical capacity, and the need for transformational change, both within lending organisations and across the banking sector.
Dynamic Continuum of Molecular Assemblies for Controlling Cell Fates
Authors: Wang Huaimin , Feng Zhaoqianqi , Xu Bing
Published: April 2019

Biological systems have evolved to create a structural and dynamic continuum of bio‐macromolecular assemblies for the purpose of optimizing the system′s functions. The formation of these dynamic higher‐order assemblies is precisely controlled by biological cues. However, controlling the self‐assembly of synthetic molecules spatiotemporally in or on live cells is still a big challenge, especially for performing functions. This concept article introduces the use of in situ reactions as a spatiotemporal control to form assemblies of small molecules that induce cell morphogenesis or apoptosis. After briefly introducing a representative example of a natural dynamic continuum of the higher‐order assemblies, we describe enzyme‐instructed self‐assembly (EISA) for constructing dynamic assemblies of small molecules, then discuss the use of EISA for controlling cell morphogenesis and apoptosis. Finally, we provide a brief outlook to discuss the future perspective of this exciting new research direction.
Coordination of Platinum to α‐Synuclein Inhibits Filamentous Aggregation in Solution
Authors: Pan Bin‐Bin , Yang Yin , Liu Hui‐Zhong , Li Yi‐Hua , Su Xun‐Cheng
Published: April 2019

Accumulation of filamentous aggregates of α‐synuclein (AS) in Lewy bodies and neurites is characteristic of neurodegenerative diseases such as Parkinson's disease. Inhibition of AS fibrillation is helpful for understanding of AS aggregate structure and for developing chemical therapies. Herein, we report that the PtII‐containing antitumor drug cisplatin suppresses filamentous aggregation of AS in solution. PtII thus contrasts strongly with reported transition‐metal ions such as MnII, FeIII, and CuII, which accelerate AS aggregation. Interaction between PtII and the side chains of methionine and histidine residues was essential for inhibition of AS fibrillation. Binding of PtII to AS did not change the protein′s overall random coil structure, as indicated by solution‐state two‐dimensional NMR and circular dichroism spectroscopy; and a solution of the AS⋅PtII complex remained free of filamentous aggregates. Our results constitute interesting new information about the biological chemistry of metal ions in Parkinson's disease and might open new lines of research into the suppression of filamentous aggregation.