bluuebunny/crossref_metadata_2025 huggingface dataset:
Selective Laser Melting and Remelting of Pure Tungsten
Authors: Xiong Zhengang , Zhang Panpan , Tan Chaolin , Dong Dongdong , Ma Wenyou , Yu Kun
Published: February 2020

The processing of pure tungsten encounters a substantial challenge due to its high melting point and intrinsic brittleness. Selective laser melting (SLM) technique is gaining popularity and offers an excellent processing approach for refractory metals. Herein, dense pure tungsten specimens are produced by optimizing SLM processing parameters. The mechanical property of the SLM‐produced tungsten with an ultimate compressive strength of about 1200 MPa, which is obviously superior to that reported in other literature, is achieved. The increased laser energy input is instrumental in raising density and surface roughness of tungsten specimens. Interestingly, additional remelting of processed layers during SLM improves the surface quality and the microstructure and achieves the highest relative density (98.4% ± 0.5%). After laser remelting, the surface roughness is reduced by 28% and a large number of fine grains are obtained. The flow of fluids caused by remelting plays a decisive role in the formation of fine grains and the defect level. Therefore, these findings offer a new insight into SLM of pure tungsten.
Analysis of the Combined Strengthening Effect of Solute Atoms and Precipitates on Creep of Aluminum Alloys
Authors: Fernández Ricardo , Bokuchava Gizo , Toda-Caraballo Isaac , Bruno Giovanni , Turchenko Vitalii , Gorshkova Yulia , González-Doncel Gaspar
Published: February 2020

The creep strengthening mechanisms in (age‐hardenable) aluminum alloys are analyzed on the basis of a new microstructural study of powder samples, an analysis of a comprehensive revision of creep data from the literature, and a new modeling approach. A strategy based on the strength difference (SD) method to separate the contributions of solid solution atoms and precipitates to creep strengthening is proposed. The new methodology considers the combination of the two contributions avoiding the need of a threshold stress term in the creep equation. The contribution of both precipitates and solid solution is taken into account by means of the analysis of the lattice parameter variation with aging time. For this study, powders of two commercial AA2xxx alloys have been analyzed using diffraction methods. The experimental results are modeled using Lubarda's approach combined with the SD method.
Microenergy Harvesters Based on Fluorinated Ethylene Propylene Piezotubes
Authors: Zhukov Sergey , von Seggern Heinz , Zhang Xiaoqing , Xue Yuan , Ben Dali Omar , Pondrom Perceval , Sessler Gerhard M. , Kupnik Mario
Published: February 2020

Energy harvesting from vibrations provides power to low‐energy‐consuming electronics for standalone and wearable devices as well as for wireless and remote sensing. In this contribution, compact tubular ferroelectret energy harvesters utilizing a single‐tube design are presented. Such single‐tube harvesters can be fabricated from commercially available fluorinated ethylene propylene (FEP) tubes with wall thicknesses of 25 and 50 μm, respectively, by mechanical deformation at elevated temperature. It is demonstrated that the generated power is highly dependent on parameters such as wall thickness, load resistance, and seismic mass. Utilizing a seismic mass of 80 g at resonance frequencies around 80 Hz and an input acceleration of 1 × g (9.81 m s−2 rms), output powers up to 300 μW can be reached for a transducer with 25 μm thick walls.
Engineering of Droplet Charges in Microfluidic Chips
Authors: He Rongxiang , Ruan Meilin , Qi Yuyang , Liu Hongni , Zhang Zhengtao , Chen Chaohui , Chao Yiping , Liu Yumin , Chen Yong
Published: February 2020

Droplet‐based technologies, which utilize the surface charge characterization of droplets, are used in fluorescence‐activated cell sorting and energy harvesting. Herein, the influence of droplet charges on microchips is investigated via surface engineering. An electrical field is applied to deflect the droplets in a microchannel, thereby enabling a qualitative analysis of the droplet charge. In a glass polydimethylsiloxane (PDMS)‐boned microchip, the droplet charge decreases when the microchannel is changed from a single‐sided to a three‐sided rectangular microstructure. When the ionic concentration of the droplet increases from 1 μm to 10 mm, droplet charges decrease by ≈78%. Meanwhile, a Au film is patterned in the microchannel, and 11‐aminoundecanethiol hydrochloride (AUT) and 12‐mercaptododecanoic acid (MDA) are modified to modulate the Au surface characterization. Compared with the glass–PDMS‐bonded microchannel, the Au film can suppress the streaming potential to decrease the droplet charges. After modification with MDA and AUT, the droplet charges increase. Therefore, the microchannel structures, ionic concentration, and substrate surface properties can be utilized to modulate the droplet charges, which can be widely used in droplet‐based energy harvesting and biological and chemical sample sorting.
Auger Effect Assisted Perovskite Electroluminescence Modulated by Interfacial Minority Carriers
Authors: Yuan Shuai , Liu Qing‐Wei , Tian Qi‐Sheng , Jin Yan , Wang Zhao‐Kui , Liao Liang‐Sheng
Published: February 2020

Perovskite‐based light‐emitting diodes (PeLEDs) have exhibited promising potential; however, their operational lifetimes are far from expectation. The large bias of the device during operation has been demonstrated as one of main reasons for accelerated device failure. To mitigate such a predicament, interfacial Auger effect (IAE) assisted sub‐bandgap voltage electroluminescence (EL) is a potential pathway to decrease the electric field intensity in each functional layer. However, the properties of a desirable IAE are still poorly understood. Herein, the underlying mechanism of IAE based on the injection characteristics of interfacial minority carriers at the Auger effect interface is investigated. Consequently, the prerequisites and the secondary conditions for the realization of IAE are proposed. Taking advantage of IAE assisted EL, the fabricated PeLEDs exhibit ultralow operational voltage, ignorable roll‐off, and improved operational stability. The findings in this work not only pave the way toward a feasible approach to enhance the stability of PeLEDs, but also highlight the potential of sub‐bandgap voltage EL in future display and lighting applications, especially in series circuits and tandem structures.
Single‐Crystal Hybrid Perovskite Platelets on Graphene: A Mixed‐Dimensional Van Der Waals Heterostructure with Strong Interface Coupling
Authors: Liu Zhixiong , You Lu , Faraji Nastaran , Lin Chun‐Ho , Xu Xiangming , He Jr‐Hau , Seidel Jan , Wang Junling , Alshareef Husam N. , Wu Tom
Published: February 2020

Van der Waals (vdW) heterostructures open up excellent prospects in electronic and optoelectronic applications. In this work, mixed‐dimensional metal‐halide perovskite/graphene heterostructures are prepared through selective growth of CH3NH3PbBr3 platelets on patterned single‐layer graphene using chemical vapor deposition. Preferred growth of single‐crystal CH3NH3PbBr3 platelets on graphene surfaces is achieved, which is accompanied by significant photoluminescence quenching. Raman spectra reveal that perovskite platelets cause p‐type doping in the graphene layer. A significant Fermi level decrease of 272 meV in graphene is estimated, which corresponds to a high doping density of 7.5 × 1012 cm−2. Surface potentials measured by Kelvin probe force microscopy indicate a negatively charged perovskite surface under illumination, which is consistent with the upward band bending deduced from conducting atomic force microscopy measurements. Moreover, a field‐effect phototransistor is fabricated using the perovskite/graphene heterostructure channel, and the increased Dirac voltage under illumination confirms an enhanced p‐type character in graphene. These findings enrich the understanding of strong interface coupling in such mixed‐dimensional vdW heterostructures and pave the way toward novel perovskite‐based optoelectronic devices.
Ligand‐Exchange‐Induced Amorphization of Pd Nanomaterials for Highly Efficient Electrocatalytic Hydrogen Evolution Reaction
Authors: Cheng Hongfei , Yang Nailiang , Liu Guigao , Ge Yiyao , Huang Jingtao , Yun Qinbai , Du Yonghua , Sun Cheng‐Jun , Chen Bo , Liu Jiawei , Zhang Hua
Published: February 2020

Various kinds of amorphous materials, such as transition metal dichalcogenides, metal oxides, and metal phosphates, have demonstrated superior electrocatalytic performance compared with their crystalline counterparts. Compared to other materials for electrocatalysis, noble metals exhibit intrinsically high activity and excellent durability. However, it is still very challenging to prepare amorphous noble‐metal nanomaterials due to the strong interatomic metallic bonding. Herein, the discovery of a unique thiol molecule is reported, namely bismuthiol I, which can induce the transformation of Pd nanomaterials from face‐centered‐cubic (fcc) phase into amorphous phase without destroying their integrity. This ligand‐induced amorphization is realized by post‐synthetic ligand exchange under ambient conditions, and is applicable to fcc Pd nanomaterials with different capping ligands. Importantly, the obtained amorphous Pd nanoparticles exhibit remarkably enhanced activity and excellent stability toward electrocatalytic hydrogen evolution in acidic solution. This work provides a facile and effective method for preparing amorphous Pd nanomaterials, and demonstrates their promising electrocatalytic application.
Organic Small Molecule Activates Transition Metal Foam for Efficient Oxygen Evolution Reaction
Authors: Zhang Jing , Jiang Wen‐Jie , Niu Shuai , Zhang Hantang , Liu Jie , Li Haiyang , Huang Gui‐Fang , Jiang Lang , Huang Wei‐Qing , Hu Jin‐Song , Hu Wenping
Published: February 2020

Developing low‐cost, highly efficient, and durable electrocatalysts for oxygen evolution reaction (OER) is essential for the practical application of electrochemical water splitting. Herein, it is discovered that organic small molecule (hexabromobenzene, HBB) can activate commercial transition metal (Ni, Fe, and NiFe) foam by directly evolving metal nanomeshes embedded in graphene‐like films (M‐NM@G) through a facile Br‐induced solid‐phase migration process. Systematic investigations indicate that HBB can conformally generate graphene‐like network on bulk metal foam substrate via the cleavage of CBr bonds and the formation of CC linkage. Simultaneously, the cleaved CBr fragments can efficiently extract metal atoms from bulk substrate, in situ producing transition metal nanomeshes embedded in the graphene‐like films. As a result, such functional nanostructure can serve as an efficient OER electrocatalyst with a low overpotential and excellent long‐term stability. Specifically, the overpotential at 100 mA cm−2 is only 208 mV for NiFe‐NM@G, ranking the top‐tier OER electrocatalysts. This work demonstrates an intriguing general strategy for directly transforming bulk transition metals into nanostructured functional electrocatalysts via the interaction with organic small molecules, opening up opportunities for bridging the application of organic small molecules in energy technologies.
Ultrathin Single Layer Metasurfaces with Ultra‐Wideband Operation for Both Transmission and Reflection
Authors: Akram Muhammad Rizwan , Ding Guowen , Chen Ke , Feng Yijun , Zhu Weiren
Published: February 2020

Artificially engineered metasurfaces provide extraordinary wave control at the subwavelength scale. However, metasurfaces proposed so far suffer due to limited bandwidths. In this paper, extremely thin metasurfaces made of single metallic layer is experimentally presented for ultra‐wideband operation from 9.3 to 32.5 GHz (with a fractional band of 112%), working at both transmission and reflection modes simultaneously. The phase control is achieved by azimuthally rotating the scatterer based on Pancharatnam–Berry phase principle. Nearly uniform efficiency (≈25%), approaching the theoretical limit of the infinitely thin metasurface, is achieved throughout the operation band. Finally, the proposed design is implemented for applications, e.g., the generation of electromagnetic waves carrying orbital angular momentums as well as anomalous reflections and refractions. The metasurfaces are characterized numerically and experimentally and the results are in good agreements.
Amyloid Fibrils Aerogel for Sustainable Removal of Organic Contaminants from Water
Authors: Peydayesh Mohammad , Suter Meret Kim , Bolisetty Sreenath , Boulos Samy , Handschin Stephan , Nyström Laura , Mezzenga Raffaele
Published: February 2020

Water contamination by organic pollutants is ubiquitous and hence a global concern due to detrimental effects on the environment and human health. Here, it is demonstrated that amyloid fibrils aerogels are ideal adsorbers for removing organic pollutants from water. To this end, amyloid fibrils prepared from β‑lactoglobulin, the major constituent of milk whey protein, are used as building blocks for the fabrication of the aerogels. The adsorption of Bentazone, Bisphenol A, and Ibuprofen, as model pollutants, is evaluated under quasi‐static conditions, without use of energy or pressure. Through adsorption by amyloid fibrils aerogel, excellent removal efficiencies of 92%, 78%, and 98% are demonstrated for Bentazone, Bisphenol A, and Ibuprofen, respectively. Furthermore, the maximum adsorption capacity of amyloid fibrils aerogel for Bentazone, Bisphenol A, and Ibuprofen is 54.2, 50.6, and 69.6 mg g−1, respectively. To shed light on the adsorption equilibrium process, adsorption isotherms, binding constants, saturation limits, and the effect of pH are evaluated. Finally, the regeneration of the aerogel over three consecutive cycles is studied, exhibiting high reusability with no significant changes in its removal performance. These results point at amyloid fibrils aerogels as a sustainable, efficient, and inexpensive technology for alleviating the ubiquitous water contamination by organic pollutants.
Synthesis of 1H‐Pyrrolo[1,2‐a]indoles via Lewis Acid‐Catalyzed Annulation of Propargylic Alcohols with 2‐Ethynylanilines
Authors: Du Li‐Juan , Han Ya‐Ping , Zhang Hong‐Yu , Zhang Yuecheng , Zhao Jiquan , Liang Yong‐Min
Published: February 2020

A novel highly efficient, environmentally benign Lewis acid‐catalyzed, and protection‐free protocol for the construction of valuable polycyclic products bearing a 1H‐pyrrolo[1,2‐a]indole scaffold is described, starting from readily available propargylic alcohols and 2‐ethynylanilines. The one‐pot transformation entails the cleavage of one C−O bond, and the construction of two C−N bonds and one C−C double bond. This unique operationally simple method is performed under mild conditions and in air, producing water as the only byproduct; it is scalable and demonstrates good functional group compatibility and broad scope.

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Transition Metal‐Free Synthesis of α‐Aminophosphine Oxides through C(sp3)−P Coupling of 2‐Azaallyls
Authors: Wang Jing , Deng Guogang , Liu Chunxiang , Chen Zhuo , Yu Kaili , Chen Wen , Zhang Hongbin , Yang Xiaodong
Published: February 2020

Radical reactions have been widely applied in C−P bond‐forming strategies. Most of these strategies require initiators, transition metal catalysts, or organometallic reagents. Herein, a transition metal‐free C(sp3)−P bond formation to prepare α‐aminophosphine oxides via deprotonative radical coupling processes of 2‐azaallyls with chlorodiphenylphosphine oxides was presented. Deprotonation of N‐benzyl imines may generate super‐electron‐donor (SED) 2‐azaallyl anions that reduced chlorodiphenylphosphine oxides to phosphine oxide radicals. Single‐electron transfer (SET) process transformed the 2‐azaallyl anions into 2‐azaallyl radicals, which may couple with phosphine oxide radicals to construct C−P bonds. The deprotonative radical coupling approach enables the synthesis of α‐aminophosphine oxides bearing various functional groups under mild conditions and without precious transition metal catalysts or oxidants.

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Simultaneous Optimization of Drug Combination Dose‐Ratio Sequence with Innovative Design and Active Learning
Authors: Wang Aiting , Xu Hongquan , Ding Xianting
Published: February 2020

Strategies for identifying potential drug combinations provide great benefits for the clinical treatment of complex diseases. However, existing approaches primarily focus on optimization of drug combinations and doses without comprehensive joint consideration of drug sequence, which compresses the therapeutic space. Herein, a novel combinatorial drug screening technique is proposed, named innovative design and active learning (IDEAL). This approach integrates innovative design, experimentation, and active learning. IDEAL allows for accurate predictions on the most efficacious drug combination, drug doses, and drug sequence with minimal amount of experimental effort. In this study, IDEAL is applied to lymphoma treatment, which successfully identifies the best drug‐dose sequence combination of chemotherapeutics on Raji cells. The IDEAL optimized regimen indicates that both drug dose and sequence are critical to ensure the optimal phenotype efficacy. This research offers an efficient methodology to identify the optimal drug administration setups in combination therapy.
Regulation of cGAS‐Mediated Immune Responses and Immunotherapy
Authors: Saeed Abdullah F. U. H. , Ruan Xinglin , Guan Hongxin , Su Jingqian , Ouyang Songying
Published: February 2020

Early detection of infectious nucleic acids released from invading pathogens by the innate immune system is critical for immune defense. Detection of these nucleic acids by host immune sensors and regulation of DNA sensing pathways have been significant interests in the past years. Here, current understandings of evolutionarily conserved DNA sensing cyclic GMP‐AMP (cGAMP) synthase (cGAS) are highlighted. Precise activation and tight regulation of cGAS are vital in appropriate innate immune responses, senescence, tumorigenesis and immunotherapy, and autoimmunity. Hence, substantial insights into cytosolic DNA sensing and immunotherapy of indispensable cytosolic sensors have been detailed to extend limited knowledge available thus far. This Review offers a critical, in‐depth understanding of cGAS regulation, cytosolic DNA sensing, and currently established therapeutic approaches of essential cytosolic immune agents for improved human health.
Limits to Profit Maximization as a Guide to Behavior Change
Authors: Weersink Alfons , Fulton Murray
Published: February 2020

Economists have long been interested in why farmers decide to adopt new technologies. Modeling decision making requires modeling behavior; the key behavioral assumption is profit maximization. In addition, most empirical studies assume a binary decision—adopt or not. This paper argues that adoption should be understood as a process with multiple stages in which the final decision to use the new technology only occurs if the previous stages are completed. While profit considerations are clearly important, particularly in the later stages of the process, they need to be supplemented with other social and cognitive considerations, particularly in the early stages. Understood this way, profit maximization assumptions can provide predictions for the upper or lower bounds of adoption. The adoption rate suggested by profit maximization will be an upper bound if noneconomic factors are expected to either slow down or deter adoption, while that rate will be a lower bound if noneconomic factors are expected to encourage adoption. To capture these elements, econometric models need to pay attention to the timing of decisions and use techniques that condition later‐stage decisions on previous stage outcomes. In addition, the paper suggests the use of expert systems that have economic, learning and social aspects explicitly built into them would be valuable.
Understanding Adoption of Innovations and Behavior Change to Improve Agricultural Policy
Authors: Pannell David , Zilberman David
Published: February 2020

Research on the adoption of new practices and new behaviors in agriculture continues to grow and evolve, and its relevance to policy remains high. This special issue presents 10 papers that provide overviews of important aspects of the recent adoption literature, or identify gaps and opportunities in the literature. Adoption research has been innovative in a number of ways, including its recognition of adoption decision making as a process, not an event; its emphases on heterogeneity and learning; and its strong multidisciplinary flavor. There is scope for further innovation through efforts to enhance predictions of adoption, better understanding the balance between profit and non‐profit motivations, and better recognizing the influence on adoption of characteristics of the innovations, not just characteristics of the potential adopters and their contexts. Opportunities for policy include effort to support women farmers' adoption of beneficial innovations in developing countries, and use of tools and approaches from marketing in public extension programs
Corn response to banded phosphorus fertilizers with or without manure application in Eastern Canada
Authors: Parent Serge‐Étienne , Dossou‐Yovo Wilfried , Ziadi Noura , Leblanc Michael , Tremblay Gilles , Pellerin Annie , Parent Léon‐Etienne
Published: February 2020

Legacy phosphorus (P), corn (Zea mays L.) hybrids, weather conditions, and regulation on land‐applied manure affect site‐specific mineral P requirements. Mineral P fertilizers are still banded at corn seeding as insurance policy even where manure P is applied in compliance with regulation in Eastern Canada. Our objective was to measure the effects of site‐specific factors on the response of corn hybrids of the “new” era (1991+) to mineral and manure P fertilization under regulatory constraints. A dataset of 370 corn P fertilizer trials conducted between 1998 and 2004 in Quebec, Canada, comprised trials using mineral P alone (229 trials) or in combination with manure (141 trials). Linear mixed statistical models tested the effect of P fertilization on seedling biomass, grain yield, grain bulk density, and grain moisture content as affected by weather and soil indices. Early plant growth proved to be a poor indicator of final crop performance. Where no manure was applied, grain yield and quality were affected primarily by soil pH, texture, and genesis. There were responses to P additions only where the saturation index (P/Al)M3 was less than 5%. Mineral P fertilizers showed no significant effect on crop performance where manure was applied, but manured soil generally showed (P/Al)M3 percentages exceeding 5%. Banding mineral P at corn seeding where manure was applied at rates complying with the regulation and the (P/Al)M3 percentage exceeded 5% appeared to be a waste of resource under the soil and climate conditions in Eastern Canada.
Effect of slow‐release nitrogen on the nitrogen availability in an andisol and the critical nitrogen concentration in wheat
Authors: Clunes John , Pinochet Dante
Published: February 2020

The use of coated fertilizers and the concept of the critical N dilution curve are alternatives capable of improving the production efficiency of wheat (Triticum aestivum L.) crops in agro‐ecosystems. The objectives of this work were to evaluate the effect of a slow release urea‐coated fertilizer on (i) the production of wheat's shoot biomass at the anthesis stage, (ii) the concentration of N in the shoot biomass, and (iii) the N availability in the Andisol. Two fertilizers: urea and urea‐coated were evaluated using four increasing N rates and a control treatment (without fertilization), in three application strategies, during two growing seasons (late sowing [S1] and early sowing [S2]). Samples of shoot biomass and soil (0–20‐cm depths) were collected at five wheat growth stages (Z21, Z31, Z39, Z45, Z69 on the Zadoks scale). The average production of shoot biomass was 10.3 t dry matter (DM) ha–1 for S2 and 7.9 t DM ha–1 for S1 and N concentrations was between 1.0–3.0%. When using a coated urea fertilizer in this Valdivian agro‐ecosystem, no statistical differences (P < .05) in shoot biomass or wheat N concentrations were found at anthesis (Z69). Differences were principally between seasons. We therefore proposed a new adjustment to the dilution N curve, with a value concentration critical, Nc start of 3.80%, and 4.15%, for S1 and S2, respectively. Use demand parameters such as Nc adjusted to the agro‐ecosystem for wheat crop, allows to rationalize the fertilization according to inorganic N available from the soil.
Tolerance to Fusarium verticillioides infection and fumonisin accumulation in maize F1 hybrids and subsequent F2 populations
Authors: Ouko Abigael , Okoth Sheila , Netshifhefhe Nakisani E. l. , Viljoen Altus , Rose Lindy Joy
Published: February 2020

Fusarium verticillioides causes Fusarium ear rot (FER) in maize (Zea mays L.), thus reducing grain quality, yield, and contaminates grains with fumonisins. Grain infection by these fungi occurs before harvest and selection of parental lines resistant to fumonisin accumulation for breeding purposes is the most effective and environmentally friendly control strategy for F. verticillioides. This study intended to evaluate F1 hybrids and F2 breeding populations in Kenya for improved resistance to FER and fumonisin contamination. Trials were artificially inoculated and FER severity, F. verticillioides accumulation, and fumonisin contamination were determined. Inheritance of resistance was also determined in the F1 hybrids. CML444 × MIRTC5, R119W × CKL05015, and CML444 × CKL05015 exhibited little to no FER and had the least fungal and fumonisin contamination, respectively. Inbred lines CML495, CKL05015, and P502 had negative, significant general combining ability (GCA) estimates for F. verticillioides colonization and fumonisin contamination, but positive, significant GCA estimates for 1,000‐kernel weight, respectively. The genotype × environment interaction was the main source of variation observed in the F2 populations with R119W × CKL05015 and CML444 × CKL05015 being the most tolerant to fungal and fumonisin contamination in Kiboko and MIRTC5 × CML495 the most tolerant in Katumani.
Adaptive Calibration of Soft Sensors Using Optimal Transportation Transfer Learning for Mass Production and Long‐Term Usage
Authors: Kim DongWook , Kwon Junghan , Jeon Byungjun , Park Yong-Lae
Published: February 2020

Soft sensors suffer from high manufacturing tolerances and signal drift from long‐term usage, which degrades their practicality. Although deep learning has recently been proposed to address these issues, it is expensive in terms of data collection and processing. Therefore, an adaptive calibration method is proposed for soft sensors, suitable for mass production and long‐term usage. In addition to maintaining the original benefits of deep learning characterization, this method enables fast and accurate calibration by capturing the change in the characteristics of the sensor through domain adaptation, using optimal transportation. An offline calibration method is first described, which is for alleviating the difficulty in calibrating every single unit from mass produced soft sensors. The main advantage is that identically manufactured soft sensors in a large volume with variations can be calibrated with reduced time and effort for collecting and processing data. Online calibration is then discussed, which compensates for the parameter changes when a soft sensor is continuously used for an extended period of time. For a single sensor, even though the sensor shows signal drift from the long‐term usage, the calibrated network weights can be quickly adjusted online. Finally, the proposed adaptive calibration is experimentally evaluated using actual soft sensors.
Salze von HCN‐Cyanid‐Aggregaten: [CN(HCN)2]− und [CN(HCN)3]−
Authors: Bläsing Kevin , Harloff Jörg , Schulz Axel , Stoffers Alrik , Stoer Philip , Villinger Alexander
Published: February 2020

Obwohl reiner Cyanwasserstoff spontan polymerisieren oder sogar explodieren kann, was durch geringe Mengen an Basen (z. B. CN−) ausgelöst wird, wurde die Reaktion von flüssigem HCN mit [WCC]CN (WCC=schwach koordinierendes Kation=Ph4P, Ph3PNPPh3=PNP) untersucht. Abhängig vom Kation konnten aus flüssigem HCN Salze, welche die formalen Dihydrogentricyanid‐ [CN(HCN)2]− und Trihydrogentetracyanid‐Ionen [CN(HCN)3]− enthalten, isoliert werden, wenn die Kristallisation schnell und bei niedrigen Temperaturen durchgeführt wurde. Die Röntgenstrukturaufklärung ergab wasserstoffverbrückte lineare [CN(HCN)2]− und Y‐förmige [CN(HCN)3]− Molekülionen im Kristall. Beide Anionen können als Vertreter hochlabiler Cyanid‐HCN‐Solvate vom Typ [CN(HCN)n]− (n=1, 2, 3…) sowie als formale Polypseudohalogenidionen betrachtet werden.
Metal Alkyls with Alkylidynic Metal‐Carbon Bond Character: Key Electronic Structures in Alkane Metathesis Precatalysts
Authors: Gordon Christopher P. , Copéret Christophe
Published: February 2020

The homologation of alkanes via alkane metathesis is catalyzed at low temperatures (150 °C) by the silica‐supported species (≡SiO)WMe5 and (≡SiO)TaMe4, while (≡SiO)TaMe3Cp* is inactive. The contrasting reactivity is paralleled by differences in the 13C NMR signature; the former display significantly more deshielded isotropic chemical shifts (δiso) and almost axially symmetric chemical shift tensors, similar to what is observed in their molecular precursors TaMe5 and WMe6. Analysis of the chemical shift tensors reveals the presence of a triple‐bond character in their metal‐carbon (formally single) bond. This electronic structure is reflected in their propensity to generate alkylidynes and to participate in alkane metathesis, further supporting the role of alkylidynes as key reaction intermediates. This study establishes chemical shift as a descriptor to identify potential alkane metathesis catalysts.
Total Synthesis of Pyrolaside B: Phenol Trimerization through Sequenced Oxidative C−C and C−O Coupling
Authors: Neuhaus William C. , Kozlowski Marisa C.
Published: February 2020

A facile method to oxidatively trimerize phenols using a catalytic aerobic copper system is described. The mechanism of this transformation was probed, yielding insight that enabled cross‐coupling trimerizations. With this method, the natural product pyrolaside B was synthesized for the first time. The key strategy used for this novel synthesis is the facile one‐step construction of a spiroketal trimer intermediate, which can be selectively reduced to give the natural product framework without recourse to stepwise Ullmann‐ and Suzuki‐type couplings. As a result, pyrolaside B can be obtained expeditiously in five steps and 16 % overall yield. Three other analogues were synthesized, thus highlighting the utility of the method, which provides new accessibility to this area of chemical space. A novel xanthene was also synthesized through controlled Lewis acid promoted rearrangement of a spiroketal trimer.
Autokatalytische Carbonylarylierung mittels lokaler Freisetzung von Arylnukleophilen ausgehend von N‐Aryl‐N′‐silyldiazenen
Authors: Chauvier Clément , Finck Lucie , Irran Elisabeth , Oestreich Martin
Published: February 2020

Es wird über eine Methode zur katalytischen Erzeugung von funktionalisierten Arylalkalimetallverbindungen berichtet. Diese hochreaktiven Intermediate werden aus silylgeschützten, arylsubstituierten Diazenen durch Einwirkung von Lewis‐basischen Alkalimetallsilanolaten freigesetzt, wobei Desilylierung und Verlust von N2 eintreten. Katalytische Mengen jener Lewis‐Basen leiten die Übertragung des Arylnukleophils vom Diazen auf Carbonyl‐ und Carboxyverbindungen mit hervorragender Toleranz gegenüber funktionellen Gruppen ein. Die Arylalkalimetallverbindungen können elektrophile Substituenten wie Methoxycarbonyl‐ oder Cyangruppen sowie Halogene tragen. Die Synthese eines bislang nicht bekannten cyclophanartigen [4]Arenmakrocyclus ausgehend von einem 1,3‐Bisdiazen in Verbindung mit einem 1,4‐Dialdehyd unterstreicht das Leistungsvermögen des Ansatzes.
CsVO2F(IO3): An Excellent SHG Material Featuring an Unprecedented 3D [VO2F(IO3)]− Anionic Framework
Authors: Chen Jin , Hu Chun‐Li , Zhang Xiao‐Han , Li Bing‐Xuan , Yang Bing‐Ping , Mao Jiang‐Gao
Published: February 2020

The first alkali‐metal vanadium iodate fluoride, CsVO2F(IO3), with a novel 3D anionic framework, has been rationally designed and hydrothermally synthesized. The 3D [VO2F(IO3)]− framework in CsVO2F(IO3) is built from 0D Λ‐shaped cis‐[VO3F(IO3)2]4− polyanions via corner‐sharing of oxo anions and bridging of the iodate groups. CsVO2F(IO3) displays both a strong second‐harmonic generation (SHG) 1.1 times as strong as KTiOPO4 (KTP) under 2.05 μm laser radiation and high laser‐induced damage threshold (LIDT) of 107.9 MW cm−2. This work provides a new route to design SHG crystals with stable 3D anionic structures from low‐dimensional structural building units.
A P/N‐containing flame retardant constructed by phosphaphenanthrene, phosphonate, and triazole and its flame retardant mechanism in reducing fire hazards of epoxy resin
Authors: Cheng Jianwen , Duan Huajun , Yang Shuang , Wang Jun , Zhang Qianqian , Ding Guoping , Hu Yefa , Huo Siqi
Published: February 2020

A P/N‐containing flame retardant (PPT) constructed by phosphaphenanthrene, phosphonate, and triazole groups was successfully synthesized and used as a reactive co‐curing agent for epoxy resin (EP). The curing behavior, thermal property, combustion behavior, and flame retardant mechanism of EP thermosets were comprehensively investigated. According to the analysis of DSC and TGA, PPT accelerated the crosslinking reaction and enhanced the charring ability for EP thermosets at high temperature. The results of combustion test indicated that PPT endowed epoxy thermoset with outstanding flame retardancy. When the phosphorus content was 0.71 wt%, EP/DDS/PPT‐2 achieved a LOI value of 33.2% and passed V‐0 rating in UL‐94 test, and its peak heat release rate and total heat release were decreased by 63.7 and 30.5%, respectively, relative to EP/DDS. Moreover, the FIGRA of EP/DDS/PPT‐2 was reduced from 9.7 to 3.5 kW m−2 s−1, manifesting the significantly improved fire safety of EP thermoset. The flame retardant mechanism was summarized as two parts: (a) the barrier effect of continuous phosphorus‐rich char layers in condensed phase, (b) the quenching effect of phosphorous radicals and diluting effect of nonflammable gases in gaseous phase.
Targeted gene disruption by CRISPR/xCas9 system in Drosophila melanogaster
Authors: Ni Xu‐yang , Zhou Zhen‐dong , Huang Jia , Qiao Xiaomu
Published: February 2020

Although the Cas9 protein from Streptococcus pyogenes (SpCas9) is the most widely used clustered regularly interspaced short palindromic repeats (CRISPR) variant in genome engineering experiments, it does have certain limitations. First, the stringent requirement for the protospacer adjacent motif (PAM) sequence limits the target DNA that can be manipulated using this method in insects. Second, its complementarity specifications are not very stringent, meaning that it can sometimes cause off‐target effects at the target site. A recent study reported that an evolved SpCas9 variant, xCas9(3.7), with preference for various 5′‐NG‐3′ PAM sequences not only has the broadest PAM compatibility but also has much greater DNA specificity and lower genome‐wide off‐target activity than SpCas9 in mammalian cells. Here we applied the CRISPR/xCas9 system to target the white gene in Drosophila melanogaster, testing the genome‐editing efficiency of xCas9 at different PAM sites. On the GGG PAM site, xCas9 showed less activity than SpCas9. For the non‐NGG PAM site TGA, xCas9 could produce DNA cleavage and indel‐mediated disruption on the target gene. However, for other non‐NGG PAM sites, xCas9 showed no activity. These findings show that the evolved Cas9 variant with broad PAM compatibility is functional in Drosophila to induce heritable gene alterations, increasing the targeting range for the applications of genome editing in insects.
General Approach to Single and Hybrid Metal Oxide Fiber Structures for High‐Performance Lithium‐Ion Batteries
Authors: Xie Ling , Yan Yan , Lin Huijuan , Rui Kun , Huang Aoming , Du Min , Shen Yu , Zhu Jixin
Published: February 2020

Owing to the high specific capacity and energy density, metal oxides have become very promising electrodes for lithium‐ion batteries (LIBs). However, poor electrical conductivity accompanied with inferior cycling stability resulting from large volume changes are the main obstacles to achieve a high reversible capacity and stable cyclability. Herein, a facile and general approach to fabricate SnO2, Fe2O3 and Fe2O3/SnO2 fibers is proposed. The appealing structural features are favorable for offering a shortened lithium‐ion diffusion length, easy access for the electrolyte and reduced volume variation when used as anodes in LIBs. As a consequence, both single and hybrid oxides show satisfactory reversible capacities (1206 mAh g−1 for Fe2O3 and 1481 mAh g−1 for Fe2O3/SnO2 after 200 cycles at 200 mA g−1) and long lifespans.
Catalytic Approaches for the Direct Heterofunctionalization of Aliphatic Carboxylic Acids and Their Equivalents with Group 16 Elements
Authors: Kumar Jogendra , Rahaman Ajijur , Singh Anupam Kumar , Bhadra Sukalyan
Published: February 2020

In contrast to traditional multistep synthesis, modern organic synthesis extensively depends on the direct functionalization of unactivated C−H bonds for the construction of various C−C and C‐heteroatom bonds in atom‐ and step‐economic manner. Common aliphatic substrates, e. g. carboxylic acids and their synthetic equivalents, are regiospecifically functionalized based on either a directed approach, in which the polar directing group assists to functionalize a specific C−H bond positioned at β‐ and γ‐carbon centers, or a non‐directed approach typically leading to α‐functionalization. While numerous reviews on catalytic C−H functionalization have appeared, a concise review on the direct C(sp3)−H heterofunctionalization of carboxylic acid synthons with Group 16 elements has been awaited. The recent advances on the direct oxy‐functionalization and chalcogenation of aliphatic carboxylic acid synthons enabled by transition metal, organo‐ and photocatalysts are described herein.
Solubilization of poorly water‐soluble bioactive molecules in neutral aqueous media by complexation with renatured β‐1,3‐1,6‐glucan nanoparticles
Authors: Kodama Ayumu , Nakagawa Akifumi , Nonoguchi Yuki , Sakurai Haruka , Yano Chieko , Suzuki Toshio , Koumoto Kazuya
Published: February 2020

The design of scaffolds for solubilizing/dispersing poorly water‐soluble bioactive molecules in neutral aqueous media is a major challenge of functional food, pharmaceuticals, and cosmetics development, as highlighted by the plethora of corresponding solubilization/dispersion strategies. Herein, renatured β‐1,3‐1,6‐glucan (r‐glucan) nanoparticles prepared by neutralization of alkali‐denatured β‐1,3‐1,6‐glucan and subsequent centrifugation are used as a host to disperse water‐insoluble bioactive molecules (curcumin, all‐trans‐retinoic acid, and rebamipide) by simple mixing of host and guest solutions. Curcumin in the r‐glucan cavity is found to be stacked in the form of J‐aggregates and twisted along the helix, and is demonstrated to be retained for significantly longer than curcumin in the corresponding γ‐cyclodextrin (γ‐CD) complex. Specifically, curcumin incorporated in γ‐CD is released within 5.5 hours, whereas that in the r‐glucan complex is released very slowly, with 12% of curcumin in the latter complex retained after 31‐day incubation at 37°C. Thus, inclusion protocol simplicity and slow release ability make r‐glucan nanoparticles a potential carrier scaffold for various applications.
Monodentate Benzo[d]imidazole‐Based Iridium(III) Complexes and Their Dual Fluorescent and Phosphorescent Emissions
Authors: Ryu Chan Hee , Kim Mingi , Sohn Changho , Hong Ju Hyun , Im Sehee , Kim So Yeon , Lee Kang Mun
Published: February 2020

We herein reported the preparation of three heteroleptic iridium complexes possessing the monodentate benzo[d]imidazole ligand, namely IrBzH (bis[2‐(4,6‐difluorophenyl)pyridinato‐C^N](1‐pyridin‐2‐yl)‐1H‐benzo[d]imidazolate)iridium(III)), IrBzCN (bis[2‐(4,6‐difluorophenyl)pyridinato‐C^N](2‐(1H‐benzo[d]imidazolate‐1‐yl)isonicotinonitrile)iridium(III)), and IrBzBr (bis[2‐(4,6‐difluorophenyl)pyridinato‐C′N](1‐(4‐bromopyridin‐2‐yl)‐1H‐benzo[d]imidazolate)iridium(III)). The successful preparation of these complexes was confirmed by multinuclear NMR spectroscopy and elemental analysis, while the molecular structures were determined by X‐ray diffraction. The photoluminescence spectra of all three complexes in toluene at ambient temperature exhibited a dual‐emissive pattern in the high‐ and low‐energy regions. For IrBzCN and IrBzBr, the emissions were simultaneous in accordance with the excitation energies (λem = 342 and 370 nm), indicating that exhibiting both fluorescent (in the high‐energy region) and phosphorescent (in the low‐energy region) emissions is an inherent property of these complexes. Time‐dependent density functional theory calculations verified that each fluorescent emission of the Ir complexes is associated with a ligand‐to‐ligand charge transfer transition, and the phosphorescent emission can be attributed to typical triplet metal‐to‐ligand charge transfer transitions between Ir3+ and the difluorophenylpyridine ligand.
Association of aspirin resistance with 4‐hydroxynonenal and its impact on recurrent cerebral infarction in patients with acute cerebral infarction
Authors: Guo Juan , Wang Jue , Guo Yanxia , Feng Juan
Published: February 2020

Objectives

To investigate the association of aspirin resistance (AR) with the plasma 4‐hydroxynonenal (4‐HNE) level and its impact on recurrent cerebral infarction (CI) in patients with acute cerebral infarction (ACI) who were receiving aspirin therapy.

Methods

One hundred and fifty‐four ACI patients who previously received aspirin therapy (100 mg/day) were enrolled. Whole urine (for measuring 11dhTXB2 and creatinine) along with blood (for measuring the plasma 4‐HNE level) were collected at least 7 days after the patients received aspirin. A cutoff of 1500 pg/mg of 11dhTXB2/ creatinine was used to determine AR. A follow‐up period to monitor recurrence CI events was 1 year. In addition, blood testing was performed when the patients were first admitted to hospital.

Results

Forty‐six of the 154 enrolled patients (29.9%) were found to be AR. No statistical difference in age, sex, hypertension, diabetes mellitus, coronary disease, smoking status, NIHSS score, TOAST classification, platelet count, thrombocytocrit, LDL‐C, HDL‐C, TG, and TC was found between the AR and aspirin‐sensitive (AS) patients, but the plasma 4‐HNE level was found to be higher in the AR patients than AS patients (p < .05). Multiple logistic regression analysis showed that the 4‐HNE level was associated with a higher risk of AR (OR = 1.034; 95% CI = 1.011–1.058; p < .05). Moreover, 1‐year follow‐up showed that AR was more prevalent in patients with recurrent CI (26 (56.6%)) than those without (20/(43.5%)) (p < .001).

Conclusions

The plasma 4‐HNE level is strongly associated with AR and thus may be a factor contributing to AR. Patients with AR have a greater risk of recurrence CI.
Physical framework for a counselling environment in India: Thematic analysis of counsellors' perceptions
Authors: Dey Anjali Miriam , Kumar Aneesh
Published: February 2020

The influence of the physical environment on the counselling process is an inevitable part of a counselling session. However, there is little insight in Indian research into the desirable elements of the physical environment of the counselling room that helps facilitate a counselling session. Interviews were conducted with 10 professional counsellors in India. Thematic analysis of the data brought out various Basic and Organising themes under the following three Global themes: (a) Elements of the physical framework; (b) Counsellor's perspectives about the physical framework in counselling; and (c) Motivation to build a framework. The findings show how counsellors can systematise the physical framework to help construct the counselling session effectively.
A Pronucleotide Probe for Live‐Cell Imaging of Protein AMPylation
Authors: Kielkowski Pavel , Buchsbaum Isabel Y. , Becker Tobias , Bach Kathrin , Cappello Silvia , Sieber Stephan A.
Published: February 2020

Conjugation of proteins to AMP (AMPylation) is a prevalent post‐translational modification (PTM) in human cells, involved in the regulation of unfolded protein response and neural development. Here we present a tailored pronucleotide probe suitable for in situ imaging and chemical proteomics profiling of AMPylated proteins. Using straightforward strain‐promoted azide–alkyne click chemistry, the probe provides stable fluorescence labelling in living cells.
A New Cell‐Based AI‐2‐Mediated Quorum Sensing Interference Assay in Screening of LsrK‐Targeted Inhibitors
Authors: Gatta Viviana , Tomašič Tihomir , Ilaš Janez , Zidar Nace , Peterlin Mašič Lucija , Barančoková Michaela , Frlan Rok , Anderluh Marko , Kikelj Danijel , Tammela Päivi
Published: February 2020

Quorum sensing (QS), a bacterial communication strategy, has been recognized as one of the control mechanisms of virulence in bacteria. Thus, targeting QS offers an interesting opportunity to impair bacterial pathogenicity and develop antivirulence agents. Aiming to enhance the discovery of QS inhibitors, we developed a bioreporter Escherichia coli JW5505 pET‐Plsrlux and set up a cell‐based assay for identifying inhibitors of autoinducer‐2 (AI‐2)‐mediated QS. A comparative study on the performance of target‐ versus cell‐based assays was performed, and 91 compounds selected with the potential to target the ATP binding pocket of LsrK, a key enzyme in AI‐2 processing, were tested in an LsrK inhibition assay, providing 36 hits. The same set of compounds was tested by the AI‐2‐mediated QS interference assay, resulting in 24 active compounds. Among those, six were also found to be active against LsrK, whereas 18 might target other components of the pathway. Thus, this AI‐2‐mediated QS interference cell‐based assay is an effective tool for complementing target‐based assays, yet also stands as an independent assay for primary screening.
Fatal outcome of malignant transformation of hidradenitis suppurativa: A case report and literature review
Authors: Nielsen Valdemar Wendelboe , Jørgensen Astrid‐Helene Ravn , Thomsen Simon Francis
Published: February 2020

Squamous cell carcinoma arising in hidradenitis suppurativa (HS) is a rare albeit the most serious complication in HS, with a reported fatality of up to 42.9%. This calls for greater clinical awareness in patients with long‐standing chronic HS.
Perivascular epithelioid cell tumor (PEComa) of the pterygopalatine fossa
Authors: Dougherty Michael I. , Payne Spencer C. , Gupta Akriti , Mattos Jose L.
Published: February 2020

Perivascular epithelioid cell tumors (PEComas) are a rare group of mesenchymal tumors associated with tuberous sclerosis. These tumors are typically treated with resection and rarely recur or exhibit malignant behavior. A 78‐year‐old woman presented with an incidentally discovered pterygopalatine fossa/retroantral mass. Excisional biopsy was performed and revealed pathology consistent with PEComa. Upon review of the literature, there have been 43 reported cases of PEComa of the head and neck. There is only one previously reported case of PEComa in the skull base, and none reported in the pterygopalatine fossa. Of note, the previously reported case of skull base PEComa involved an aggressive tumor with widespread metastasis. Here, we report the first case of a PEComa of the pterygopalatine fossa/retroantral region, which was treated conservatively. This rare pathology should be considered in the differential diagnosis for atypical skull base tumors.