bluuebunny/crossref_metadata_2025 huggingface dataset:
Revealing Trap States in Lead Sulphide Colloidal Quantum Dots by Photoinduced Absorption Spectroscopy
Authors: Kahmann Simon , Sytnyk Mykhailo , Schrenker Nadine , Matt Gebhard J. , Spiecker Erdmann , Heiss Wolfgang , Brabec Christoph J. , Loi Maria A.
Published: December 2017

Due to their large surface to volume ratio, colloidal quantum dots (CQDs) are often considered to exhibit a significant amount of surface defects. Such defects are one possible source for the formation of in‐gap states (IGS), which can enhance the recombination of excited carriers, i.e., work as electrical traps. These traps are investigated for lead sulphide CQDs of different size, covered with different ligands using a mid‐infrared photoinduced absorption (PIA) technique. The obtained PIA spectra reveal two distinct absorption bands, whose position depends on the particle size, i.e., the electronic confinement in the CQDs. Smaller particles exhibit deeper traps. The chemical nature of the capping ligand does not affect the resulting position other than due to its change in confinement, but better passivating species lead to smaller signals. Furthermore, ligand specific narrow lines observed are superimposed on the broad electronic background of the PIA spectra, which is attributed to Fano resonances caused by the interplay of the narrow molecular vibrations and the continuum of trap states. Mid‐infrared photoinduced absorption represents a valuable tool to unravel distributions of IGS in CQDs and allows for an assessment of the quality of ligand exchanged films. These findings have implications for understanding the performances of CQD‐based (opto‐) electronic devices, such as solar cells, transistors, or quantum dot light emitting diodes, which are limited by frequent carrier trapping events.
Hybrid Perovskite‐Based Position‐Sensitive Detectors
Authors: Ashar A. Z. , Ganesh N. , Narayan K. S.
Published: December 2017

A light‐dependent position‐sensitive detector (PSD) is demonstrated using an active layer of organic–inorganic halide perovskite. The lateral device is demonstrated using indium tin oxide coated glass as common back electrode and gold as the top electrodes. Apart from the linearity and the large span of position sensing range, the PSD response is characterized by a sizable responsivity. The device geometry for PSD also permits a high spatial resolution and transient signal mapping of the lateral photovoltage. These results can be understood in the framework of drift‐diffusion model and offer another valuable use for hybrid perovskite systems.
Field Effect Transistors Based on In Situ Fabricated Graphene Scaffold–ZrO2 Nanofilms
Authors: Pang Qingqing , Chen Hongliang , Wang Xiuyan , Wang Tao , Wang Deyan , Feng Shaoguang , Lu Hongliang , Li Qiaowei
Published: December 2017

Ionic liquid‐gated electric double layer transistors (EDLTs), bottom‐gated field effect transistors (FETs), and vertical Schottky barrier transistors are fabricated by utilizing in situ prepared heterostrutural nanofilms. The nanofilms feature graphene scaffolds on top of high‐k ZrO2 dielectric, which allow transfer‐free fabrication of various transistor devices. Both the ionic liquid‐gated EDLT and bottom‐gated FET feature p‐type characteristic behaviors with notable Ion/Ioff ratio and effective carrier modulation ability. Furthermore, the applicability of the layered structure is demonstrated in construction of vertical Schottky barrier transistors, and evident rectification behavior is revealed. With the capability to construct multilayer heterostructural nanofilms on various substrates and further optimizing the interfaces between these layers for targeted modulation, the presented electronic materials show potential application in graphene‐based transistor fabrication.
Broadband Enhancement of PbS Quantum Dot Solar Cells by the Synergistic Effect of Plasmonic Gold Nanobipyramids and Nanospheres
Authors: Chen Si , Wang Yong jie , Liu Qipeng , Shi Guozheng , Liu Zeke , Lu Kunyuan , Han Lu , Ling Xufeng , Zhang Han , Cheng Si , Ma Wanli
Published: December 2017

For the first time, the plasmonic gold bipyramids (Au BPs) are introduced to the PbS colloidal quantum dot (CQD) solar cells for improved infrared light harvesting. The localized surface plasmon resonance peaks of Au BPs matches perfectly with the absorption peaks of conventional PbS CQDs. Owing to the geometrical novelty of Au BPs, they exhibit significantly stronger far‐field scattering effect and near‐field enhancement than conventional plasmonic Au nanospheres (NSs). Consequently, device open‐circuit voltage (Voc) and short‐circuit current (Jsc) are simultaneously enhanced, while plasmonic photovoltaic devices based on Au NSs only achieve improved Jsc. The different effects and working mechanisms of these two Au nanoparticles are systematically investigated. Moreover, to realize effective broadband light harvesting, Au BPs and Au NSs are used together to simultaneously enhance the device optical and electrical properties. As a result, a significantly increased power conversion efficiency (PCE) of 9.58% is obtained compared to the PCE of 8.09% for the control devices due to the synergistic effect of the two plasmonic Au nanoparticles. Thus, this work reveals the intriguing plasmonic effect of Au BPs in CQD solar cells and may provide insight into the future plasmonic enhancement for solution‐processed new‐generation solar cells.
Prescribing Functional Additives for Treating the Poor Performances of High‐Voltage (5 V‐class) LiNi0.5Mn1.5O4/MCMB Li‐Ion Batteries
Authors: Xu Gaojie , Pang Chunguang , Chen Bingbing , Ma Jun , Wang Xiao , Chai Jingchao , Wang Qingfu , An Weizhong , Zhou Xinhong , Cui Guanglei , Chen Liquan
Published: December 2017

In this paper, tris(trimethylsilyl) phosphite (TMSP) and 1,3‐propanediolcyclic sulfate (PCS) are unprecedentedly prescribed as binary functional additives for treating the poor performances of high‐voltage (5 V‐class) LiNi0.5Mn1.5O4/MCMB (graphitic mesocarbon microbeads) Li‐ion batteries at both room temperature and 50 °C. The high‐voltage LiNi0.5Mn1.5O4/MCMB cell with binary functional additives shows a preponderant discharge capacity retention of 79.5% after 500 cycles at 0.5 C rate at room temperature. By increasing the current intensity from 0.2 to 5 C rate, the discharge capacity retention of the high‐voltage cell with binary functional additives is ≈90%, while the counterpart is only ≈55%. By characterizations, it is rationally demonstrated that the binary functional additives decompose and participate in the modification of solid–electrolyte interface layers (both electrodes), which are more conductive, protective, and resistant to electrolyte oxidative/reductive decompositions (accompanying active‐Li+ consuming parasitic reactions) due to synergistic effects. Specifically, the TMSP additive can stabilize LiPF6 salt and scavenge erosive hydrofluoric acid. More encouragingly, at 50 °C, the high‐voltage cell with binary functional additives holds an ultrahigh discharge capacity retention of 79.5% after 200 cycles at 1 C rate. Moreover, a third designed self‐extinguishing flame‐retardant additive of (ethoxy)‐penta‐fluoro‐cyclo‐triphosphazene (PFPN) is introduced for reducing the flammability of the aforementioned binary functional additives containing electrolyte.
Balancing High Open Circuit Voltage over 1.0 V and High Short Circuit Current in Benzodithiophene‐Based Polymer Solar Cells with Low Energy Loss: A Synergistic Effect of Fluorination and Alkylthiolation
Authors: Du Zhengkun , Bao Xichang , Li Yonghai , Liu Deyu , Wang Jiuxing , Yang Chunming , Wimmer Reinhard , Städe Lars Wagner , Yang Renqiang , Yu Donghong
Published: December 2017

Based on the most recently significant progress within the last one year in organic photovoltaic research from either alkylthiolation or fluorination on benzo[1,2‐b:4,5‐b′]dithiophene moiety for high efficiency polymer solar cells (PSCs), two novel simultaneously fluorinated and alkylthiolated benzo[1,2‐b:4,5‐b′] dithiophene (BDT)‐based donor–acceptor (D–A) polymers, poly(4,8‐bis(5′‐((2″‐ethylhexyl)thio)‐4′‐fluorothiophen‐2′‐yl)benzo[1,2‐b:4,5‐b′]dithiophene‐2,6‐diyl)‐alt‐2′‐ethylhexyl‐3‐fluorothieno[3,4‐b]thiophene‐2‐carboxylate (PBDTT‐SF‐TT) and poly(4,8‐bis(5′‐((2″‐ethylhexyl)thio)‐4′‐fluorothiophen‐2′‐yl)benzo[1,2‐b:4,5‐b′]dithiophene‐2,6‐diyl)‐alt‐1,3‐bis(thiophen‐2‐yl)‐5,7‐bis(2‐ethylhexyl)benzo[1,2‐c:4,5‐c′]dithiophene‐4,8‐dione (PBDTT‐SF‐BDD), namely, via an advantageous and synthetically economic route for the key monomer are reported herein. Synergistic effects of fluorination and alkylthiolation on BDT moieties are discussed in detail, which is based on the superior balance between high Voc and large Jsc when PBDTT‐SF‐TT/PC71BM and PBDTT‐SF‐BDD/PC71BM solar cells present their high Voc as 1.00 and 0.97 V (associated with their deep highest occupied molecular orbital level of −5.54 and −5.61 eV), a moderately high Jsc of 14.79 and 14.70 mA cm−2, and thus result a high power conversion efficiency of 9.07% and 9.72%, respectively. Meanwhile, for PBDTT‐SF‐TT, a very low energy loss of 0.59 eV is pronounced, leading to the promisingly high voltage, and furthermore performance study and morphological results declare an additive‐free PSC from PBDTT‐SF‐TT, which is beneficial to practical applications.
Quantifying Efficiency Loss of Perovskite Solar Cells by a Modified Detailed Balance Model
Authors: Sha Wei E. I. , Zhang Hong , Wang Zi Shuai , Zhu Hugh L. , Ren Xingang , Lin Francis , Jen Alex K.‐Y. , Choy Wallace C. H.
Published: December 2017

A modified detailed balance model is built to understand and quantify efficiency loss of perovskite solar cells. The modified model captures the light‐absorption‐dependent short‐circuit current, contact and transport‐layer‐modified carrier transport, as well as recombination and photon‐recycling‐influenced open‐circuit voltage. The theoretical and experimental results show that for experimentally optimized perovskite solar cells with the power conversion efficiency of 19%, optical loss of 25%, nonradiative recombination loss of 35%, and ohmic loss of 35% are the three dominant loss factors for approaching the 31% efficiency limit of perovskite solar cells. It is also found that the optical loss climbs up to 40% for a thin‐active‐layer design. Moreover, a misconfigured transport layer introduces above 15% of energy loss. Finally, the perovskite‐interface‐induced surface recombination, ohmic loss, and current leakage should be further reduced to upgrade device efficiency and eliminate hysteresis effect. This work contributes to fundamental understanding of device physics of perovskite solar cells. The developed model offers a systematic design and analysis tool to photovoltaic science and technology.
High Thermoelectric zT in n‐Type Silver Selenide films at Room Temperature
Authors: Perez‐Taborda Jaime Andres , Caballero‐Calero Olga , Vera‐Londono Liliana , Briones Fernando , Martin‐Gonzalez Marisol
Published: December 2017

In this work, a zT value as high as 1.2 at room temperature for n‐type Ag2Se films is reported grown by pulsed hybrid reactive magnetron sputtering (PHRMS). PHRMS is a novel technique developed in the lab that allows to grow film of selenides with different compositions in a few minutes with great quality. The improved zT value reported for room temperature results from the combination of the high power factors, similar to the best values reported for bulk Ag2Se (2440 ± 192 µW m−1 K−2), along with a reduced thermoelectric conductivity as low as 0.64 ± 0.1 W m−1 K−1. The maximum power factor for these films is of 4655 ± 407 µW m−1 K−2 at 103 °C. This material shows promise to work for room temperature applications. Obtaining high zT or, in other words, high power factor and low thermal conductivity values close to room temperature for thin films is of high importance to develop a new generation of wearable devices based on thermoelectric heat recovery.
3D TiC/C Core/Shell Nanowire Skeleton for Dendrite‐Free and Long‐Life Lithium Metal Anode
Authors: Liu Sufu , Xia Xinhui , Zhong Yu , Deng Shengjue , Yao Zhujun , Zhang Liyuan , Cheng Xin‐Bing , Wang Xiuli , Zhang Qiang , Tu Jiangping
Published: December 2017

Construction of stable dendrite‐free Li metal anode is crucial for the development of advanced Li–S and Li–air batteries. Herein, self‐supported TiC/C core/shell nanowire arrays as skeletons and confined hosts of molten Li forming integrated trilayer TiC/C/Li anode are described. The TiC/C core/shell nanowires with diameters of 400–500 nm exhibit merits of good lithiophilicity, high electrical conductivity, and abundant porosity. The as‐prepared TiC/C/Li anode exhibits prominent electrochemical performance with a small hysteresis of less than 85 mV beyond 200 cycles (3.0 mA cm−2) as well as a very high Coulombic efficiency up to 98.5% for 100 cycles at 1.0 mA cm−2. When the structured anode is coupled with lithium iron phosphate or sulfur cathode, the assembled full cells with trilayer TiC/C/Li anodes display enhanced capability retention and improved Coulombic efficiency. This is ascribed to the unique TiC/C matrix, which can not only provide interspace for accommodating “hostless” Li, but also afford interconnected rapid transfer paths for electrons and ions with low local current densities, leading to effective inhabitation growth of Li dendrites and lower interfacial resistance. A fresh way for construction of advanced stable Li metal anodes is provided in this work.
Reverse Bias Behavior of Halide Perovskite Solar Cells
Authors: Bowring Andrea R. , Bertoluzzi Luca , O'Regan Brian C. , McGehee Michael D.
Published: December 2017

The future commercialization of halide perovskite solar cells relies on improving their stability. There are several studies focused on understanding degradation under operating conditions in light, but little is known about the stability of these solar cells under reverse bias conditions. Reverse bias stability is important because shaded cells in a module are put into reverse bias by the illuminated cells. In this paper, a phenomenological study is presented of the reverse bias behavior of halide perovskite solar cells and it is shown that reverse bias can lead to a partially recoverable loss in efficiency, primarily caused by a decrease in V
OC. A general mechanism is proposed, supported by drift–diffusion simulations, to explain how these cells breakdown via tunneling caused by accumulated ionic defects and suggests that the reversible loss in efficiency may be due to an electrochemical reaction of these defects. Finally, the implications of these phenomena are discussed and how they can possibly be addressed is also discussed.
A Wireless Triboelectric Nanogenerator
Authors: Mallineni Sai Sunil Kumar , Dong Yongchang , Behlow Herbert , Rao Apparao M. , Podila Ramakrishna
Published: December 2017

A new “wireless” paradigm for harvesting mechanical energy via a 3D‐printed wireless triboelectric nanogenerator (W‐TENG) comprised of an ecofriendly graphene polylactic acid (gPLA) nanocomposite and Teflon is demonstrated. The W‐TENG generates very high output voltages >2 kV with a strong electric field that enables the wireless transmission of harvested energy over a distance of 3 m. The W‐TENG exhibited an instantaneous peak power up to 70 mW that could be wirelessly transmitted for storage into a capacitor obviating the need for hard‐wiring or additional circuitry. Furthermore, the use of W‐TENG for wireless and secure actuation of smart‐home applications such as smart tint windows, temperature sensors, liquid crystal displays, and security alarms either with a single or a specific user‐defined passcode of mechanical pulses (e.g., Fibonacci sequence) is demonstrated. The scalable additive manufacturing approach for gPLA‐based W‐TENGs, along with their high electrical output and unprecedented wireless applications, is poised for revolutionizing the present mechanical energy harvesting technologies.
Simulation of gas separation using partial element stage cut modeling of hollow fiber membrane modules
Authors: Gilassi Sina , Taghavi Seyed Mohammad , Rodrigue Denis , Kaliaguine Serge
Published: December 2017

A mathematical model is developed to simulate a gas separation process using a hollow fiber membrane module. In particular, a new numerical technique is introduced based on flash calculation. Such analysis allows identifying the required membrane properties needed to reach module performance of interest. This model is validated for six different gas separation cases taken from literature. Then, the validated model is used to investigate the effect of O2 and N2 permeances on O2 recovery and O2 mole fraction in the permeate stream. A realistic two‐stage air enrichment process is also proposed for O2 production using an industrial module with different fibers numbers. Moreover, this model is used to simulate a natural gas purification process using a single unit to determine the required membrane separation area and CH4 loss. Finally, a two‐stage process is proposed to equally enhance CH4 retentate mole fraction and decrease CH4 loss. © 2017 American Institute of Chemical Engineers AIChE J, 64: 1766–1777, 2018
Multi–source surveillance for work‐related crushing injuries
Authors: Kica Joanna , Rosenman Kenneth D.
Published: December 2017

Background

Work‐related crushing injuries are serious but preventable. For 2013 through 2015, the U.S. Bureau of Labor Statistics’ (BLS) Survey of Occupational Injuries and Illnesses (SOII) reported 1260 crushing injuries in Michigan. In 2013, Michigan initiated multi‐data source surveillance of work‐related crushing injuries.

Methods

Records from all 134 of Michigan's hospitals/emergency departments (EDs), the Workers Compensation Agency (WCA) and Michigan's Fatality Assessment Control and Evaluation (MIFACE) program were used to identify work‐related crushing injuries. Companies, where individuals were hospitalized or had an ED visit for a crushing injury, potentially had an OSHA enforcement inspection conducted.

Results

From 2013 through 2015, there were 3137 work‐related crushing injury incidents, including two fatalities. The Michigan OSHA program completed inspections at 77 worksites identified by the surveillance system.

Conclusion

The Michigan multisource surveillance system identified two and a half times more crushing injuries than BLS and was useful for initiating case‐based enforcement inspections.
Biallelic mutations in LARS2 can cause Perrault syndrome type 2 with neurologic symptoms
Authors: Kosaki Rika , Horikawa Reiko , Fujii Eriko , Kosaki Kenjiro
Published: December 2017

Perrault syndrome represents a genetically heterogeneous disorder characterized by sensorineural hearing loss in males and females and ovarian dysfunction in females. Causative genes include HARS2, HSD17B4, CLPP, C10orf2, and LARS2. Some patients with Perrault syndrome exhibit neurologic features including learning disability, cerebellar ataxia, and peripheral neuropathy and are classified as type 2 and are clinically separate from those without neurological symptoms other than a hearing loss (type 1). To date, all reported patients with LARS2 mutations (15 patients in 8 families) have been classified as type 1. Here, we report female siblings with biallelic mutations in LARS2, p.Glu294Lys, and p.Thr519Met, who were classified as type 2. The proposita developed progressive sensorineural hearing loss at 18 months and pervasive developmental disorder at 8 years, with repetitive behavior, insistence on sameness, attention deficit, tic, irritability, and an ataxic gait. At age 15 years, she was diagnosed as having primary amenorrhea with elevated FSH and LH and a decreased estradiol; ultrasound and magnetic resonance imaging examinations revealed a small uterus and no detectable ovaries. The proposita's younger sister presented with neonatal sensorineural hearing loss and a mild delay in motor and speech development. She was diagnosed as having primary amenorrhea with endocrinologic and radiographic findings that were comparable to those of her sister. She had difficulty with reading comprehension, and had trouble with open‐ended test questions at 12 years of age. We concluded that Perrault syndrome patients with LARS2 mutations are at risk for neurologic problems, despite previous notions otherwise.
Komplementäre Strategien für die dirigierte C(sp3)‐H‐Funktionalisierung: ein Vergleich von übergangsmetallkatalysierter Aktivierung, Wasserstoffatomtransfer und Carben‐ oder Nitrentransfer
Authors: Chu John C. K. , Rovis Tomislav
Published: December 2017

Funktionalisierungen von C(sp3)‐H‐Bindungen verkürzen und vereinfachen chemische Synthesen, indem sie die Verwendung einfacher Moleküle ermöglichen und neuartige Retrosynthesen bereitstellen. Intensive Forschungen, die auf die Entwicklung neuer Reaktionen basierend auf dem Ansatz der C‐H‐Funktionalisierung abzielten, haben zur weiten Verbreitung dieser Methoden in einer Vielzahl von Bereichen geführt. Dieser Aufsatz erörtert die Stärken und Schwächen der drei Hauptstrategien – übergangsmetallkatalysierte C‐H‐Aktivierung, 1,n‐Wasserstoffatomtransfer und übergangsmetallkatalysierter Carben‐ oder Nitrentransfer – in der gezielten Funktionalisierung nichtaktivierter C(sp3)‐H‐Bindungen. Für jede Strategie werden der Anwendungsbereich, die Reaktivität verschiedener C‐H‐Bindungen, die Position der reagierenden C‐H‐Bindungen bezüglich der dirigierenden Gruppe und die stereochemischen Auswirkungen mit Beispielen aus der Literatur veranschaulicht. Das Ziel dieses Aufsatzes ist es, dem Anwender von C‐H‐Funktionalisierungsreaktionen eine Orientierungshilfe zu geben und künftige Forschungen auf diesem Gebiet anzuregen.
A Molecular Approach to Manganese Nitride Acting as a High Performance Electrocatalyst in the Oxygen Evolution Reaction
Authors: Walter Carsten , Menezes Prashanth W. , Orthmann Steven , Schuch Jona , Connor Paula , Kaiser Bernhard , Lerch Martin , Driess Matthias
Published: December 2017

The scalable synthesis of phase‐pure crystalline manganese nitride (Mn3N2) from a molecular precursor is reported. It acts as a superiorly active and durable electrocatalyst in the oxygen evolution reaction (OER) from water under alkaline conditions. While electrophoretically deposited Mn3N2 on fluorine tin oxide (FTO) requires an overpotential of 390 mV, the latter is substantially decreased to merely 270 mV on nickel foam (NF) at a current density of 10 mA cm−2 with a durability of weeks. The high performance of this material is due to the rapid transformation of manganese sites at the surface of Mn3N2 into an amorphous active MnOx overlayer under operation conditions intimately connected with metallic Mn3N2, which increases the charge transfer from the active catalyst surface to the electrode substrates and thus outperforms the electrocatalytic activity in comparison to solely MnOx‐based OER catalysts.
Generating Hydrated Electrons for Chemical Syntheses by Using a Green Light‐Emitting Diode (LED)
Authors: Naumann Robert , Lehmann Florian , Goez Martin
Published: December 2017

We present the first working system for accessing and utilizing laboratory‐scale concentrations of hydrated electrons by photoredox catalysis with a green light‐emitting diode (LED). Decisive are micellar compartmentalization and photon pooling in an intermediate that decays with second‐order kinetics. The only consumable is the nontoxic and bioavailable vitamin C. A turnover number of 1380 shows the LED method to be on par with electron generation by high‐power pulsed lasers, but at a fraction of the cost. The extreme reducing power of the electron and its long unquenched life as a ground‐state species are synergistic. We demonstrate the applicability to the dechlorination, defluorination, and hydrogenation of compounds that are inert towards all other visible‐light photoredox catalysts known to date. A comprehensive mechanistic investigation from microseconds to hours yields results of general validity for photoredox catalysis with photon pooling, allowing optimization and upscaling.
Slow Magnetic Relaxation and Single‐Molecule Toroidal Behaviour in a Family of Heptanuclear {CrIIILnIII6} (Ln=Tb, Ho, Er) Complexes
Authors: Vignesh Kuduva R. , Langley Stuart K. , Swain Abinash , Moubaraki Boujemaa , Damjanović Marko , Wernsdorfer Wolfgang , Rajaraman Gopalan , Murray Keith S.
Published: December 2017

The synthesis, magnetic properties, and theoretical studies of three heterometallic {CrIIILnIII6} (Ln=Tb, Ho, Er) complexes, each containing a metal topology consisting of two Ln3 triangles connected via a CrIII linker, are reported. The {CrTb6} and {CrEr6} analogues display slow relaxation of magnetization in a 3000 Oe static magnetic field. Single‐crystal measurements reveal opening up of the hysteresis loop for {CrTb6} and {CrHo6} molecules at low temperatures. Ab initio calculations predict toroidal magnetic moments in the two Ln3 triangles, which are found to couple, stabilizing a con‐rotating ferrotoroidal ground state in Tb and Ho examples and extend the possibility of observing toroidal behaviour in non DyIII complexes for the first time.
Kooperative Bildung einer langreichweitig geordneten Wasserschicht auf der Fe3O4(111)‐Oberfläche
Authors: Mirabella Francesca , Zaki Eman , Ivars‐Barceló Francisco , Li Xiaoke , Paier Joachim , Sauer Joachim , Shaikhutdinov Shamil , Freund Hans‐Joachim
Published: December 2017

Die ersten Elementarschritte in der Adsorption von Wasser auf der Magnetit(111)‐Oberfläche und die atomare Struktur der Wasser/Metalloxid‐Grenzfläche werden kontrovers diskutiert. Hier werden experimentelle Befunde präsentiert, die durch Infrarot‐Reflexions‐Absorptions‐Spektroskopie und temperaturprogrammierte Desorption erhalten wurden. Unterstützende DFT‐Rechnungen zeigen, dass Wassermoleküle an Fetet‐ und O‐Atomen dissoziativ unter Bildung zweier Hydroxo‐Spezies adsorbieren. Diese wirken als Anker für weitere Wassermoleküle, wobei Dimere entstehen. Diese ordnen sich zu einer definierten (2×2)‐Überstruktur an. Die Entstehung dieser geordneten Wasserschicht erfolgt durch eine kooperative Wechselwirkung zwischen den Dimeren und wird durch den Aufbau eines 2D‐Netzwerks über H‐Brücken angetrieben.
Complementary Strategies for Directed C(sp3)−H Functionalization: A Comparison of Transition‐Metal‐Catalyzed Activation, Hydrogen Atom Transfer, and Carbene/Nitrene Transfer
Authors: Chu John C. K. , Rovis Tomislav
Published: December 2017

The functionalization of C(sp3)−H bonds streamlines chemical synthesis by allowing the use of simple molecules and providing novel synthetic disconnections. Intensive recent efforts in the development of new reactions based on C−H functionalization have led to its wider adoption across a range of research areas. This Review discusses the strengths and weaknesses of three main approaches: transition‐metal‐catalyzed C−H activation, 1,n‐hydrogen atom transfer, and transition‐metal‐catalyzed carbene/nitrene transfer, for the directed functionalization of unactivated C(sp3)−H bonds. For each strategy, the scope, the reactivity of different C−H bonds, the position of the reacting C−H bonds relative to the directing group, and stereochemical outcomes are illustrated with examples in the literature. The aim of this Review is to provide guidance for the use of C−H functionalization reactions and inspire future research in this area.
Synthesis and properties of polylactide terpolymers P(LLA‐TMC‐GA) catalyzed by zirconium (IV) acetylacetonate
Authors: Wen Shaohua , Li Yongfei , Chen Weixing , Lei Yaping , Luo Chunyan , Hou Yonggang
Published: December 2017

A series of L‐lactide (LLA), 1,3‐trimethylene carbonate (TMC) and glycolide (GA) terpolymers (LTG) of different monomer molar ratios were synthesized by using ring‐opening copolymerization. An effective and low‐toxic zirconium (IV) acetylacetonate Zr(Acac)4was used as catalyst. The viscosity‐average molecular weights (Mη) of obtained polymers were all above 2.2×104 g/mol. The chemical structure and viscosity of terpolymers were confirmed by Fourier transform infrared spectroscopy (FTIR),1H nuclear magnetic resonance (1HNMR),13C nuclear magnetic resonance (13CNMR) and an Ubbelohde viscometer. The thermal and mechanical properties were investigated by means of differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), X‐ray diffraction (XRD) and stress‐strain measurements. Results suggested that all terpolymers were amorphous and showed good thermal stability. Also it was found that elongation increased with the decreasing of LLA unit. More importantly, terpolymers displayed shape memory property when deformation temperatures were 14‐15 °C aboveTg.
RAPTA complexes containing N‐substituted Tetrazole scaffolds: Synthesis, characterization and Antiproliferative activity
Authors: Mandal Poulami , Malviya Novina , Kundu Bidyut Kumar , Dhankhar Sandeep Singh , Nagaraja C.M. , Mukhopadhyay Suman
Published: December 2017

This work describes the synthesis of a series of Ru(II)‐Arene (Arene=p‐cymene, benzene) complexes using different N‐substituted tetrazole ligands and their PTA analogues. All the complexes have been characterized thoroughly using different analytical techniques. Antiproliferative activity of the synthesized complexes against different cell lines indicates remarkable activity of certain complexes up to nanomolar level. In few cases introduction of water soluble PTA (PTA = 1,3,5‐ triaza‐7‐phospha‐tricyclo‐[3.3.1.1]decane) ligand induce significant cytotoxic activity in the ruthenium complex with respect to their chloro analogues, particularly against Jurkat and MCF‐7 cell lines. Interaction with different biomolecules and stability of the RAPTA complexes have been explored in pseudo‐pharmacological conditions.
Formation of PdNiZn thin film at oil‐water interface: XPS study and application as Suzuki‐Miyaura catalyst
Authors: Fatahi Parvin , Jafar Hoseini S.
Published: December 2017

Nanosheet of PdNiZn and nanosphere of PdNiZn/reduced‐graphene oxide (RGO) with sub‐3 nm spheres have been successfully synthesized through a facile oil‐water interfacial strategy. The morphology and composition of the films were determined by X‐ray diffraction (XRD), X‐ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), scanning electron microscopy (SEM), energy dispersive analysis of X‐ray (EDAX) and elemental mapping. In the present study, we have developed a method to minimize the usage of precious Pd element. Due to the special structure and intermetallic synergies, the PdNiZn and PdNiZn/RGO nanoalloys exhibited enhanced catalytic activity and durability relative to Pd nanoparticles in Suzuki‐Miyaura C‐C cross‐coupling reaction. Compared to classical cross‐coupling reactions, this method has the advantages of a green solvent, short reaction times, low catalyst loading, high yields and reusability of the catalysts.
Kinetics of continuous production of β‐carotene in an airlift bioreactor
Authors: Taavoni Shoeib , Habibi Alireza , Varmira Kambiz , Alipour Sajad
Published: December 2017

The focus in the present work was on the continuous β‐carotene production from free fatty acids supplied by the soap stock as a sole carbon source for Rhodotorula rubra cells in an airlift bioreactor. The effects of dilution rate on the cell growth and β‐carotene production were studied by both freely suspended‐ and immobilized‐cell systems in the chemostat operations. The results showed that the immobilization of the cell on natural sponge of loofah significantly increased the optimum and maximum dilution rates from 0.0375 to 0.05 hr−1 and 0.055 to 0.150 hr−1, respectively. The immobilization process has practical role in balancing of cell proliferation in the matrix and wash out the grown cells containing β‐carotene from the bioreactor where β‐carotene productivity was enhanced from 5.4 to 23.4 mg L−1 hr−1 using the immobilized cell technology.
Enhancement of the mechanical properties and thermostability of poly(vinyl alcohol) nanofibers by the incorporation of sodium chloride
Authors: Shi Yan , Zhao Yuming , Li Xinhua , Yan Dongpeng , Cao Ding , Fu Zhifeng
Published: December 2017

The mechanical properties and thermostability of poly(vinyl alcohol) (PVA) nanofiber mats have been obviously improved by the incorporation of sodium chloride (NaCl). The tensile properties including tensile strength and modulus of membranes with an addition of 1.0 wt % NaCl increased from 2.51 to 4.22 MPa and 33.0 to 176.30 MPa, respectively, more than 160 and 700% of those of the electrospun pure PVA membranes. Moreover, thermogravimetric analysis showed that the initial decomposition temperature (Ti) and the half decomposing temperature (T50%) of PVA nanofibers with the addition of NaCl were at least 26 and 59 °C higher than that of pure PVA nanofibers, respectively, indicating a strong interaction between the PVA and the salt ions. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 45981.
Comparative mucoadhesive study of hyaluronic acid‐based conjugates on different mucosae
Authors: Laffleur Flavia
Published: December 2017

The incentive of this study was to provide a detailed mucoadhesive comparison on adhesive properties on diverse mucosal surfaces such as nasal, buccal, and vaginal mucosa, respectively. Mucoadhesive hyaluronic acid–cysteine ethyl ester (HA–SH) conjugate was synthesized by the anchorage of sulfhydryl groups (SH) on the polymeric backbone of HA via amide bond formation between the carboxylic acid moieties of hyaluronic acid and sulfhydryl groups of cysteine ethyl ester. Histology assay in terms of alcian blue staining was performed on mucosal tissue in order to evaluate the potential impact on viability. The proficiency of water uptake was studied in various simulated body fluid. Moreover, mucoadhesive assays based on rotating cylinder, total work of adhesion, and maximum detachment force were carried out on various mucosae. The findings revealed in presence of 2.7‐, 2.6‐, and 1.25‐fold improvement in swelling behavior in comparison to unmodified HA on nasal, buccal, and vaginal mucosa. Furthermore, mucoadhesive studies showed a 3.2‐, 2.6‐, 2.6‐fold more extended residence time on nasal, buccal, and vaginal in presence of HA–SH in comparison to unmodified HA, respectively. Taken together, the comprehensive mucoadhesive study serve as guidance in the development of mucoadhesive drug delivery systems for versatile application. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46071.
Layer‐by‐layer fabrication of nacre inspired epoxy/MMT multilayered composites
Authors: Batool Sadia , Gill Rohama , Arshad Muhammad , Siddiqi Humaira Masood , Qureshi Shahid Saeed
Published: December 2017

The organic–inorganic hybrid multilayered composites are prepared using a unique combination of poly[(o‐cresyl glycidyl ether)‐co‐formaldehyde] (CNER), amino modified montmorillonite (NH2‐MMT), and polyethyleneimine (PEI). This tricomponent composite multilayer PEI(CNER/NH2‐MMT/PEI)n deposited via layer‐by‐layer technique is based upon synergistic combination of covalent and hydrogen bonding. The growth of multilayer was monitored using UV–vis spectroscopy and ellipsometry. When subjected to optical analyses, the prepared multilayered composite films revealed profound optical transmittance ∼83%–87%. The surface morphological analysis by atomic force microscopy and scanning electron microscopy revealed uniform arrangement of organic–inorganic components with relative increase in intensity of elements (C, N, O, Si) as confirmed by X‐ray photoelectron spectroscopy studies. The multilayered composites possess 1.99 GPa hardness making them potential candidate for a number of applications where mechanical strength is desired. Moreover, significant resistance against alkaline and organic solvents at minimal deterioration of circa 0.12% has also been observed for the prepared films. The epoxy clay based thin films being robust, scratch resistant, hydrophilic, chemically inert, and mechanically strong are potential candidates for advanced environmental applications. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46079.
United States–China Trade: President Trump's Misunderstandings
Authors: Huenemann Ralph W.
Published: December 2017

President Trump's analysis of the persistent United States–China trade imbalance reveals fundamental misunderstandings of basic economics. During the 2016 campaign, candidate Trump made an important Big Promise with two facets: to bring back American jobs from other countries (especially China) and to eliminate the American trade deficit. But, as pointed out by Barack Obama in his farewell address, many of the American jobs were lost to factory automation, not to imports. Furthermore, if China's central bank had pursued a less interventionist foreign exchange rate policy, most of the labor‐intensive imports from China would have been produced in other low‐wage countries, not in domestic factories. Finally, and most importantly, the persistent American foreign trade deficits (with many countries, not just with China) arise from the domestic imbalance between taxes and government expenditures. Unless this budget imbalance is dealt with, the foreign trade imbalance will necessarily continue.
Design, synthesis, in silico and antiproliferative evaluation of novel pyrazole derivatives as VEGFR‐2 inhibitors
Authors: Ravula Parameshwar , Vamaraju Harinadha Babu , Paturi Manichandrika , Sharath Chandra Janivara Nanjunde Gowda Narendra
Published: December 2017

As the blockade of the VEGFR‐2 signaling pathway is a viable approach in cancer therapy, the present study focuses on a series of pyrazole based VEGFR‐2 inhibitors that were designed on the basis of the hybridization approach, supported by docking and in silico computational studies. The designed compounds were synthesized through facile synthetic methods and the structures were confirmed by 1H NMR, 13C NMR, MS and elemental analysis. The compounds were screened for in vitro antiproliferative activity against the HT‐29 (human colon cancer) and MCF‐7 (human breast cancer) cell lines by MTT assay. The compounds were also studied for in vitro inhibitory activity against VEGFR‐2 kinase. Among all the tested compounds, compound 6h emerged as a potent agent in the antiproliferative study against HT‐29 and MCF‐7 cells, with IC50 values of 2.36 and 6.59 μM, respectively. Moreover, the same compound exhibited the highest VEGFR‐2 inhibitory activity with an IC50 value of 1.89 μM. In docking studies, the designed compounds showed similar and essential key interactions as those of known VEGFR‐2 inhibitors. The present study may lead to new molecules in the development of anticancer agents targeting VEGFR‐2.
Motion Control of a Nonholonomic Mobile Manipulator in Task Space
Authors: Zhou Shengfeng , Pradeep Yazhini C. , Zhu Ming , Amezquita‐Semprun Kendrick , Chen Peter
Published: December 2017

In this paper, the motion control of a mobile manipulator subjected to nonholonomic constraints is investigated. The control objective is to design a computed‐torque controller based on the coupled dynamics of the mobile manipulator. The proposed controller achieves the capability of simultaneous tracking of a reference velocity for the mobile base and a reference trajectory for the end‐effector. The aforementioned reference velocity and trajectory are defined in the task space, such task setting imitates the actual working conditions of a mobile manipulator and thus makes the control problem practical. To solve this tracking problem, a steering velocity is firstly designed based on the first‐order kinematic model of the nonholonomic mobile base via dynamic feedback linearization. The main merit of the proposed steering velocity design is that it directly utilizes the reference velocity set in the task space without requiring the knowledge of a reference orientation. A torque controller is subsequently developed based on a proposed Lyapunov function which explicitly considers the coupled dynamics of the mobile manipulator to ensure the mobile base and end‐effector track the reference velocity and trajectory respectively. This proposed computed‐torque controller is able to realize asymptotic stability of both the base velocity tracking error and the end‐effector motion tracking error. Simulations are conducted to demonstrate the effectiveness of the proposed controller.
Viability Criteria for a Switched System on Bounded Polyhedron
Authors: Lv JianFeng , Gao Yan , Zhao Na
Published: December 2017

The viability of a switched system on a bounded polyhedron set, which is expressed by some linear inequalities, is investigated. Based on nonsmooth analysis and the properties of the tangent cone, a necessary and sufficient condition for viability is proposed. It is shown that the viability of a system is equivalent to the consistency of some systems of linear inequalities. Specifically, a viability condition for a switched system on a bounded polyhedron is presented. According to this condition, determining the viability of a bounded polyhedron can be transformed into verifying certain conditions at vertices of each facet. The method of determining viability, which transforms verifying the condition from infinite points to finite ones, can be implemented easily in practice. An algorithm to determine the viability for the switched system is constructed by using convex analysis. In addition, the approach can be extended to the switched system in which a control input is present. Finally, an example is listed to illustrate the effectiveness of the results.
Classification of early‐stage non‐small cell lung cancer by weighing gene expression profiles with connectivity information
Authors: Zhang Ao , Tian Suyan
Published: December 2017

Pathway‐based feature selection algorithms, which utilize biological information contained in pathways to guide which features/genes should be selected, have evolved quickly and become widespread in the field of bioinformatics. Based on how the pathway information is incorporated, we classify pathway‐based feature selection algorithms into three major categories—penalty, stepwise forward, and weighting. Compared to the first two categories, the weighting methods have been underutilized even though they are usually the simplest ones. In this article, we constructed three different genes’ connectivity information‐based weights for each gene and then conducted feature selection upon the resulting weighted gene expression profiles. Using both simulations and a real‐world application, we have demonstrated that when the data‐driven connectivity information constructed from the data of specific disease under study is considered, the resulting weighted gene expression profiles slightly outperform the original expression profiles. In summary, a big challenge faced by the weighting method is how to estimate pathway knowledge‐based weights more accurately and precisely. Only until the issue is conquered successfully will wide utilization of the weighting methods be impossible.
Production of cellulosic organic acids via synthetic fungal consortia
Authors: Scholz Scott A. , Graves Ian , Minty Jeremy J. , Lin Xiaoxia N.
Published: December 2017

Consolidated bioprocessing (CBP) is a potential breakthrough technology for reducing costs of biochemical production from lignocellulosic biomass. Production of cellulase enzymes, saccharification of lignocellulose, and conversion of the resulting sugars into a chemical of interest occur simultaneously within a single bioreactor. In this study, synthetic fungal consortia composed of the cellulolytic fungus Trichoderma reesei and the production specialist Rhizopus delemar demonstrated conversion of microcrystalline cellulose (MCC) and alkaline pre‐treated corn stover (CS) to fumaric acid in a fully consolidated manner without addition of cellulase enzymes or expensive supplements such as yeast extract. A titer of 6.87 g/L of fumaric acid, representing 0.17 w/w yield, were produced from 40 g/L MCC with a productivity of 31.8 mg/L/hr. In addition, lactic acid was produced from MCC using a fungal consortium with Rhizopus oryzae as the production specialist. These results are proof‐of‐concept demonstration of engineering synthetic microbial consortia for CBP production of naturally occurring biomolecules.
Meta-analysis of the procedural risks of carotid endarterectomy and carotid artery stenting over time
Authors: Lokuge K , de Waard D D , Halliday A , Gray A , Bulbulia R , Mihaylova B
Published: December 2017

Background

Stroke/death rates within 30 days of carotid endarterectomy (CEA) and carotid artery stenting (CAS) in RCTs inform current clinical guidelines. However, the risks may have changed in recent years with wider use of effective stroke prevention therapies, especially statins, improved patient selection and growing operator expertise. The aim of this study was to investigate whether the procedural stroke/death risks from CEA and CAS have changed over time.

Methods

MEDLINE and Embase were searched systematically from inception to May 2016 for observational cohort studies of CEA and CAS. Studies included reported on more than 1000 patients, with 30-day outcomes after the procedure according to patients' symptom status (recent stroke or transient ischaemic attack). Restricted maximum likelihood random-effects and meta-regressions methods were used to synthesize procedural stroke/death rates of CEA and CAS according to year of study recruitment completion.

Results

Fifty-one studies, including 223 313 patients undergoing CEA and 72 961 undergoing CAS, were reviewed. Procedural stroke/death risks of CEA decreased over time in symptomatic and asymptomatic patients. Risks were substantially lower in studies completing recruitment in 2005 or later, both in symptomatic (5·11 per cent before 2005 versus 2·68 per cent from 2005 onwards; P = 0·002) and asymptomatic (3·17 versus 1·50 per cent; P < 0·001) patients. Procedural stroke/death rates of CAS did not change significantly over time (4·77 per cent among symptomatic and 2·59 per cent among asymptomatic patients). There was substantial heterogeneity in event rates and recruitment periods were long.

Conclusions

Risks of procedural stroke/death following CEA appear to have decreased substantially. There was no evidence of a change in stroke/death rates following CAS.
How consumers “see” a visually warm store: Differences between affective and cognitive processors
Authors: Baek Eunsoo , Choo Ho Jung , Oh Hyunjoo , Yoon So‐Yeon
Published: December 2017

Store atmosphere can influence shoppers' perceptions and behaviors. This research contributes to the literature by showing that a visually warm store atmosphere can induce psychological warmth perception among in‐store consumers. An empirical study was conducted to investigate the effect of warmth through a visually warm or cold store atmosphere on consumers' perceptions/behaviors and the moderating role of consumers' processing styles. Results (N = 181) showed that a visually warm (vs. cold) atmosphere induces the perception of intimacy toward the store among affective processors and the perception of assortment similarity among cognitive processors. Such perceptions were found to mediate the effect of the visually warm atmosphere on consumers' approach behaviors toward the store. Based on the grounded cognition theory, this study extends the current knowledge of the warmth experience on psychological perceptions to a retail context. Findings not only contribute to the extant literature of store atmospherics and retailing but they also offer practical guidelines for retailers and designers of store environments.