bluuebunny/crossref_metadata_2025_split huggingface dataset:
Low Thermal Conductivity through Dense Particle Packings with Optimum Disorder
Authors: Nutz Fabian A. , Philipp Alexandra , Kopera Bernd A. F. , Dulle Martin , Retsch Markus 
Published: February 2018

AbstractHeat transport plays a critical role in modern batteries, electrodes, and capacitors. This is caused by the ongoing miniaturization of such nanotechnological devices, which increases the local power density and hence temperature. Even worse, the introduction of heterostructures and interfaces is often accompanied by a reduction in thermal conductivity, which can ultimately lead to the failure of the entire device. Surprisingly, a fundamental understanding of the governing heat transport processes even in simple systems, such as binary particle mixtures is still missing. This contribution closes this gap and elucidates how strongly the polydispersity of a model particulate system influences the effective thermal conductivity across such a heterogeneous system. In a combined experimental and modeling approach, well‐defined mixtures of monodisperse particles with varying size ratios are investigated. The transition from order to disorder can reduce the effective thermal conductivity by as much as ≈50%. This is caused by an increase in the thermal transport path length and is governed by the number of interparticle contact points. These results are of general importance for many particulate and heterostructured materials and will help to conceive improved device layouts with more reliable heat dissipation or conservation properties in the future.
Necklace‐Like Microfibers with Variable Knots and Perfusable Channels Fabricated by an Oil‐Free Microfluidic Spinning Process
Authors: Xie Ruoxiao , Xu Peidi , Liu Yupeng , Li Lili , Luo Guoan , Ding Mingyu , Liang Qionglin 
Published: February 2018

AbstractFiber materials with different structural features, which in many cases endow the fibers extraordinary functions, are drawing considerable attention from biomedical and material researchers. Here, perfusable necklace‐like knotted microfibers are presented for the first time. Additionally, a novel microfluidic spinning method facilitates the production of variable knots and channels. Not only spindle‐, but also hemisphere‐ and petal‐knotted microfibers can be controllably fabricated. Generation and perfusion of both Janus channels and helical channel in the knotted microfibers are also shown. With no need of oil and surfactant, the spinning process is highly cytocompatible. The potential bioengineering and biomedical application of the knotted hollow microfiber is demonstrated by its cell‐encapsulation feasibility and the unique liver acinus‐like diffusion gradient in the knot. The merits of perfusability, cytocompatibility, and structural diversity of the microfibers may open more avenues for further material and biomedical investigation.
CMOS Enabled Microfluidic Systems for Healthcare Based Applications
Authors: Khan Sherjeel M. , Gumus Abdurrahman , Nassar Joanna M. , Hussain Muhammad M. 
Published: February 2018

AbstractWith the increased global population, it is more important than ever to expand accessibility to affordable personalized healthcare. In this context, a seamless integration of microfluidic technology for bioanalysis and drug delivery and complementary metal oxide semiconductor (CMOS) technology enabled data‐management circuitry is critical. Therefore, here, the fundamentals, integration aspects, and applications of CMOS‐enabled microfluidic systems for affordable personalized healthcare systems are presented. Critical components, like sensors, actuators, and their fabrication and packaging, are discussed and reviewed in detail. With the emergence of the Internet‐of‐Things and the upcoming Internet‐of‐Everything for a people–process–data–device connected world, now is the time to take CMOS‐enabled microfluidics technology to as many people as possible. There is enormous potential for microfluidic technologies in affordable healthcare for everyone, and CMOS technology will play a major role in making that happen.
Effective Carrier‐Concentration Tuning of SnO2 Quantum Dot Electron‐Selective Layers for High‐Performance Planar Perovskite Solar Cells
Authors: Yang Guang , Chen Cong , Yao Fang , Chen Zhiliang , Zhang Qi , Zheng Xiaolu , Ma Junjie , Lei Hongwei , Qin Pingli , Xiong Liangbin , Ke Weijun , Li Gang , Yan Yanfa , Fang Guojia 
Published: February 2018

AbstractThe carrier concentration of the electron‐selective layer (ESL) and hole‐selective layer can significantly affect the performance of organic–inorganic lead halide perovskite solar cells (PSCs). Herein, a facile yet effective two‐step method, i.e., room‐temperature colloidal synthesis and low‐temperature removal of additive (thiourea), to control the carrier concentration of SnO2 quantum dot (QD) ESLs to achieve high‐performance PSCs is developed. By optimizing the electron density of SnO2 QD ESLs, a champion stabilized power output of 20.32% for the planar PSCs using triple cation perovskite absorber and 19.73% for those using CH3NH3PbI3 absorber is achieved. The superior uniformity of low‐temperature processed SnO2 QD ESLs also enables the fabrication of ≈19% efficiency PSCs with an aperture area of 1.0 cm2 and 16.97% efficiency flexible device. The results demonstrate the promise of carrier‐concentration‐controlled SnO2 QD ESLs for fabricating stable, efficient, reproducible, large‐scale, and flexible planar PSCs.
A Bioinspired Interface Design for Improving the Strength and Electrical Conductivity of Graphene‐Based Fibers
Authors: Ma Tao , Gao Huai‐Ling , Cong Huai‐Ping , Yao Hong‐Bin , Wu Liang , Yu Zi‐You , Chen Si‐Ming , Yu Shu‐Hong 
Published: February 2018

AbstractGraphene‐based fibers (GBFs) are attractive for next‐generation wearable electronics due to their potentially high mechanical strength, superior flexibility, and excellent electrical and thermal conductivity. Many efforts have been devoted to improving these properties of GBFs in the past few years. However, fabricating GBFs with high strength and electrical conductivity simultaneously remains as a great challenge. Herein, inspired by nacre‐like multilevel structural design, an interface‐reinforced method is developed to improve both the mechanical property and electrical conductivity of the GBFs by introducing polydopamine‐derived N‐doped carbon species as resistance enhancers, binding agents, and conductive connection “bridges.” Remarkably, both the tensile strength and electrical conductivity of the obtained GBFs are significantly improved to ≈724 MPa and ≈6.6 × 104 S m−1, respectively, demonstrating great superiority compared to previously reported similar GBFs. These outstanding integrated performances of the GBFs provide it with great application potential in the fields of flexible and wearable microdevices such as sensors, actuators, supercapacitors, and batteries.
Ultrafast Processing of Hierarchical Nanotexture for a Transparent Superamphiphobic Coating with Extremely Low Roll‐Off Angle and High Impalement Pressure
Authors: Teisala Hannu , Geyer Florian , Haapanen Janne , Juuti Paxton , Mäkelä Jyrki M. , Vollmer Doris , Butt Hans‐Jürgen 
Published: February 2018

AbstractLow roll‐off angle, high impalement pressure, and mechanical robustness are key requirements for super‐liquid‐repellent surfaces to realize their potential in applications ranging from gas exchange membranes to protective and self‐cleaning materials. Achieving these properties is still a challenge with superamphiphobic surfaces, which can repel both water and low‐surface‐tension liquids. In addition, fabrication procedures of superamphiphobic surfaces are typically slow and expensive. Here, by making use of liquid flame spray, a silicon dioxide–titanium dioxide nanostructured coating is fabricated at a high velocity up to 0.8 m s−1. After fluorosilanization, the coating is superamphiphobic with excellent transparency and an extremely low roll‐off angle; 10 µL drops of n‐hexadecane roll off the surface at inclination angles even below 1°. Falling drops bounce off when impacting from a height of 50 cm, demonstrating the high impalement pressure of the coating. The extraordinary properties are due to a pronounced hierarchical nanotexture of the coating.
Micropatterning of Nonplanar Surfaces on 3D Devices Using Conformal Template Vacuum Bagging
Authors: Alaie Seyedhamidreza , Robinson Sanlin S. , Amiri Moghadam Amir Ali , Auge Jordyn , Datye Amit , Sidoti Hannah , Doshi Tejas , Gharaie Saleh Hassanzadeh , Min James K. , Mosadegh Bobak , Dunham Simon 
Published: February 2018

AbstractMicropatterning provides a powerful means for engineering surface properties, such as friction, adhesion, and biocompatibility, with promise for medical device applications. While soft lithography allows for micropatterning on curved surfaces, there are limitations to the level of curvature and object complexity achievable. A cost effective and simple method is realized for micropatterning complex 3D objects and is demonstrated for a variety of micropatterns, materials, and devices. The technique integrates the simple principles of soft lithography for fabrication of flexible templates, and vacuum bagging, for transfer of the patterns on arbitrary shaped nonplanar objects. The technique is demonstrated with silicones, polyurethanes, and nitinol materials ubiquitous in medical devices, due to their mechanics, biocompatibility, and hemocompatibility. Micropatterns inspired by shark skin riblets and tree frogs are demonstrated. The flexibility of this method is demonstrated by transferring patterns to various objects/devices, including 3D printed objects, soft robotic grippers, guidewires, and balloon catheters.
Sequential Photoredox Catalysis for Cascade Aerobic Decarboxylative Povarov and Oxidative Dehydrogenation Reactions of N‐Aryl α‐Amino Acids
Authors: Shao Tianju , Yin Yanli , Lee Richmond , Zhao Xiaowei , Chai Guobi , Jiang Zhiyong 
Published: February 2018

AbstractA visible‐light‐driven sequential photoredox catalysis to allow N‐aryl α‐amino acids to experience efficient cascade aerobic decarboxylative Povarov and oxidative dehydrogenation (ODH) reactions is described. With a dicyanopyrazine‐derived chromophore (DPZ) as a photoredox catalyst in both transformations, two series of valuable azaarenes, i. e., 4‐amino tetrahydroquinolines (THQs) and quinolines, were obtained in satisfactory yields featuring diverse 2‐ and 2,3‐substituent patterns. To enable the ODH reaction of 4‐amino THQs, a cooperative catalysis with N‐hydroxyphthalimide was developed. Additionally, an unprecedented synthesis of chiral N‐amino‐2‐methyl THQs with high enantioselectivities was realized.magnified image
Intermolecular C(sp3)−H Amination of Complex Molecules
Authors: Chiappini Nicholas D. , Mack James B. C. , Du Bois J. 
Published: February 2018

AbstractA general and operationally convenient method for intermolecular amination of C(sp3)−H bonds is described. This technology allows for efficient functionalization of complex molecules, including numerous pharmaceutical targets. The combination of pivalonitrile as a solvent, Al2O3 as an additive, and phenyl sulfamate as a nitrogen source affords differential reaction performance and substrate scope. Mechanistic data strongly implicate a pathway for catalyst decomposition that initiates with solvent oxidation, thus providing rationale for the marked influence of pivalonitrile on this reaction process.
Der Entwurf einer homogenen Brom‐Redoxkatalyse zur selektiven aliphatischen CH‐Bindungsfunktionalisierung
Authors: Becker Peter , Duhamel Thomas , Martínez Claudio , Muñiz Kilian 
Published: February 2018

AbstractDas Potential der homogenen Oxidationskatalyse unter Verwendung von Brom ist weitgehend unerforscht. Wir zeigen hier, dass die Kombination von Tetraalkylammoniumbromid und 3‐Chlorperbenzoesäure ein einzigartiges Katalysatorsystem für die bequeme und selektive Oxidation gesättigter C(sp3)‐H‐Bindungen unter photochemischer Initiierung mit Tageslicht bietet. Es ermöglicht eine positionsselektive intramolekulare Aminierung, wie anhand von 20 verschiedenen Beispielen gezeigt wurde. Zum ersten Mal konnte ein N‐halogeniertes Intermediat in einer katalytischen Hofmann‐Löffler‐Reaktion isoliert werden. Darüber hinaus wurde eine neuartige schnelle Eintopfsynthese von N‐Sulfonyloxaziridinen aus N‐Sulfonamiden entwickelt und für 15 Transformationen beispielhaft dargestellt. Diese bahnbrechenden Beispiele bieten ein neuartiges Konzept für die molekulare Katalyse mit Brom.
Inversion of Configuration at the Phosphorus Nucleophile in the Diastereoselective and Enantioselective Synthesis of P‐Stereogenic syn‐Phosphiranes from Chiral Epoxides
Authors: Muldoon Jake A. , Varga Balázs R. , Deegan Meaghan M. , Chapp Timothy W. , Eördögh Ádám M. , Hughes Russell P. , Glueck David S. , Moore Curtis E. , Rheingold Arnold L. 
Published: February 2018

AbstractNucleophilic substitution results in inversion of configuration at the electrophilic carbon center (SN2) or racemization (SN1). The stereochemistry of the nucleophile is rarely considered, but phosphines, which have a high barrier to pyramidal inversion, attack electrophiles with retention of configuration at P. Surprisingly, cyclization of bifunctional secondary phosphine alkyl tosylates proceeded under mild conditions with inversion of configuration at the nucleophile to yield P‐stereogenic syn‐phosphiranes. DFT studies suggested that the novel stereochemistry results from acid‐promoted tosylate dissociation to yield an intermediate phosphenium‐bridged cation, which undergoes syn‐selective cyclization.
Parahydrogen‐Based Hyperpolarization for Biomedicine
Authors: Hövener Jan‐Bernd , Pravdivtsev Andrey N. , Kidd Bryce , Bowers C. Russell , Glöggler Stefan , Kovtunov Kirill V. , Plaumann Markus , Katz‐Brull Rachel , Buckenmaier Kai , Jerschow Alexej , Reineri Francesca , Theis Thomas , Shchepin Roman V. , Wagner Shawn , Bhattacharya Pratip , Zacharias Niki M. , Chekmenev Eduard Y. 
Published: February 2018

AbstractMagnetic resonance (MR) is one of the most versatile and useful physical effects used for human imaging, chemical analysis, and the elucidation of molecular structures. However, its full potential is rarely used, because only a small fraction of the nuclear spin ensemble is polarized, that is, aligned with the applied static magnetic field. Hyperpolarization methods seek other means to increase the polarization and thus the MR signal. A unique source of pure spin order is the entangled singlet spin state of dihydrogen, parahydrogen (pH2), which is inherently stable and long‐lived. When brought into contact with another molecule, this “spin order on demand” allows the MR signal to be enhanced by several orders of magnitude. Considerable progress has been made in the past decade in the area of pH2‐based hyperpolarization techniques for biomedical applications. It is the goal of this Review to provide a selective overview of these developments, covering the areas of spin physics, catalysis, instrumentation, preparation of the contrast agents, and applications.
Control of Molar Mass Distribution by Polymerization in the Analytical Ultracentrifuge
Authors: Spinnrock Andreas , Cölfen Helmut 
Published: February 2018

AbstractMolar mass distributions are of high interest in macromolecular chemistry because they directly determine the physical and chemical properties of polymers. A principal approach to obtain and control the shape of broad molar mass distributions is adjusting the initiator concentration in free radical polymerizations. A controlled gradient of the initiator concentration should potentially lead to tailored molar mass distributions. Here we use analytical ultracentrifugation (AUC) to adjust and measure a macroinitiator's concentration gradient. Subsequent photopolymerization of a uniformly distributed monomer leads to desired chain length distributions. Resulting distributions are described and calculated by a Schulz–Flory approach. The desired concentration profiles are simulated in advance and can be detected anytime by the optical systems in the centrifuge. Therefore, tailored broad molar mass distributions can now be produced using predictions from simulations using the established theory of AUC.
The Pre‐exponential Factor in Electrochemistry
Authors: He Zheng‐Da , Chen Yan‐Xia , Santos Elizabeth , Schmickler Wolfgang 
Published: February 2018

AbstractLike many branches of science, not to mention culture in general, electrochemistry has a number of recurring topics: Areas of research that are popular for a certain time, then fade away as their possibilities seem to have been exhausted, only to return decades later as progress in experimental or theoretical techniques offer new possibilities for their investigation. A prime example are fuel cells, which have undergone five such cycles, but here we discuss a general concept of kinetics—the pre‐exponential factor of a rate constant—which has undergone two such cycles. The first cycle was in the 1950–1980s, when the methods of electrochemical kinetics were developed, and the interpretation was based on transition‐state theory. The second was triggered by the re‐discovery of Kramers theory for reactions in condensed phases. This Minireview will show that the time has come for a third cycle based on recent progress in electrocatalysis.
Understanding Value as a Key Concept in Sustaining the Perioperative Nursing Workforce
Authors: Kapaale Chaluza C. 
Published: February 2018

AbstractPerioperative nursing is faced with a staffing crisis attributed in part to minimal numbers of newly graduated nurses choosing a career in this specialty. This article analyzes and applies the concept of value to explore how to maintain an adequate perioperative nursing workforce; recruit newly graduated nurses; and encourage career professional, nurse educator, and student collaboration to generate meaningful value for perioperative nursing. This analysis revealed that value co‐creation for perioperative nursing could lead to newly graduated nurses increasingly choosing perioperative nursing as a career, and enjoying satisfying perioperative nursing careers while providing high‐quality patient care.
Surgical Fire Safety: An Ambulatory Surgical Center Quality Improvement Project
Authors: Tola Denise H. , Jillson Irene A. , Graling Paula 
Published: February 2018

AbstractSurgical team members use fire risk assessment tools to determine the risk of a surgical fire occurring and facilitate communication to reduce risk. The purposes of this quality improvement project were to improve knowledge and awareness of surgical fire risk and increase practitioners’ use of a fire risk assessment tool during the surgical safety communication process. We recruited a purposive sample of participants that included all surgical team members of a metropolitan ambulatory surgical center. We based the educational intervention on published evidence and findings of a preintervention knowledge, attitude, and practice (KAP) survey. We assessed knowledge, current practice, and practice intent using a 10‐item pretest and posttest, and used a follow‐up posttest to assess knowledge retention and practice change. The findings suggest that a brief educational intervention regarding fire risk assessment contributes to improving staff member knowledge and use of prevention strategies.
Infrared emissivity property study and conformational analysis of helical polysilane
Authors: Zhang Muyang , Zhou Yuming , He Man , Zhang Tao , Ding Qinghua 
Published: February 2018

ABSTRACTLeft and right single‐handed helical polysilane (L‐HPS and D‐HPS) and racemic helical polysilane (R‐HPS) were synthesized by the Wurtz‐type coupling reaction. The chiral dichloro(methoxycarbonyl ethyl propyl ether)methylsilane monomers applied in copolymerization were derived from methyl d/l‐lactate. The obtained polymers were characterized by 1H and 13C nuclear magnetic resonance, Fourier transform infrared spectroscopy, ultraviolet–visible spectroscopy, circular dichroism spectroscopy, gel permeation chromatography and X‐ray diffraction. Infrared emissivity (IRE) values were also investigated. Compared to R‐HPS, L‐HPS, and D‐HPS, a pair of mirror image, showed higher crystallinity, better thermal stability, and lower IRE (8–14 mm) at the values of 0.592 and 0.576, respectively. The higher regular secondary structure of HPSs was attributed to the formation of intermolecular hydrogen bonds. To further study the configurations of L‐HPS, D‐HPS, and R‐HPS, rotational isomeric state scheme with molecular dynamics simulation have been utilized. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46335.
Das neue fib Bulletin 80 – Teilsicherheitsbeiwerte für die Nachrechnung bestehender Massivbauwerke
Authors: Weber Michael , Caspeele Robby , Schnell Jürgen , Glock Christian , Botte Wouter 
Published: February 2018

AbstractDie zuverlässigkeitsbasierte Nachrechnung bestehender Tragwerke kann auf Basis verschiedener wissenschaftlicher Verfahren erfolgen. Da jedoch bisher nur wenige mit den Eurocodes kompatible Verfahren für eine praxisgerechte Anwendung existieren, kommen für die Nachrechnung bestehender Tragwerke meist semiprobabilistische Verfahren und Teilsicherheitsbeiwerte zur Anwendung, wie sie auch zur Bemessung von Neubauwerken verwendet werden. Eine solche Beurteilung bzw. Nachrechnung bestehender Tragwerke führt oft zu sehr konservativen Ergebnissen, verbunden mit aufwendigen und kostenintensiven Verstärkungsmaßnahmen.Vor diesem Hintergrund wurde in der fib Task Group 3.1 „Reliability and safety evaluation: full‐probabilistic and semi‐probabilistic methods for existing structures“ das neue Bulletin 80 „Teilsicherheitsbeiwerte für die Nachrechnung bestehender Massivbauwerke“ [1] erarbeitet, welches sowohl Empfehlungen für die Teilsicherheitsbeiwerte der Einwirkungs‐ als auch der Widerstandsseite enthält.Im vorliegenden Beitrag werden neben zwei Verfahren zur Bestimmung modifizierter Teilsicherheitsbeiwerte für die Nachrechnung bestehender Massivbauwerke nach fib Bulletin 80 [1] mit schwerpunktmäßiger Betrachtung der Widerstandsseite auch Methoden zur Anpassung des Zielzuverlässigkeitsindex nach fib Bulletin 80 [1] vorgestellt. Darüber hinaus wird das Vorgehen an einem Anwendungsbeispiel erläutert.
Exploring the structure characteristics and major channels of cytochrome P450 2A6, 2A13, and 2E1 with pilocarpine
Authors: Fan Jing‐Rong , Li Heng , Zhang Hong‐Xing , Zheng Qing‐Chuan 
Published: February 2018

AbstractThe majority of cytochromes P450 play a critical role in metabolism of endogenous and exogenous substrates, some of its products are carcinogens. Therefore, inhibition of P450 enzymes activity can promote the detoxification and elimination of chemical carcinogens. In this study, molecular dynamics (MD) simulations and adaptive steered molecular dynamics (ASMD) simulations were performed to explore the structure features and channel dynamics of three P450 isoforms 2A6, 2A13, and 2E1 bound with the common inhibitor pilocarpine. The binding free energy results combined with the PMF calculations give a reasonable ranking of binding affinity, which are consistent with the experimental data. Our results uncover how a sequence divergence of different CYP2 enzymes causes individual variations in major channel selections. On the basis of channel bottleneck and energy decomposition analysis, we propose a gating mechanism of their respective major channels in three enzymes, which may be attributed to a reversal of Phe209 in CYP2A6/2A13, as well as the rotation of Phe116 and Phe298 in CYP2E1. The hydrophobic residues not only make strong hydrophobic interactions with inhibitor, but also act as gatekeeper to regulate the opening of channel. The present study provides important insights into the structure–function relationships of three cytochrome P450s and the molecular basis for development of potent inhibitors.