bluuebunny/crossref_metadata_2025 huggingface dataset:
meta‐Selective C−H Arylation of Fluoroarenes and Simple Arenes
Authors: Liu Luo‐Yan , Qiao Jennifer X. , Yeung Kap‐Sun , Ewing William R. , Yu Jin‐Quan
Published: April 2020

Fluorine is known to promote ortho‐C−H metalation. Based upon this reactivity, we employed an activated norbornene that traps the ortho‐palladation intermediate and is then relayed to the meta position, leading to meta‐selective C−H arylation of fluoroarenes. Deuterium experiment suggests that this meta‐arylation is initiated by ortho C−H activation and the catalytic cycle is terminated by C‐2 protonation. A dual‐ligand system is crucial for the observed high reactivity and site selectivity. Applying this approach to simple benzene or other arenes also affords arylation products with good yield and site selectivity.
Room‐Temperature Guerbet Reaction with Unprecedented Catalytic Efficiency and Enantioselectivity
Authors: Ng Teng Wei , Liao Gang , Lau Kai Kiat , Pan Hui‐Jie , Zhao Yu
Published: April 2020

We report herein an unprecedented highly efficient Guerbet‐type reaction at room temperature (catalytic TON up to >6000). This β‐alkylation of secondary methyl carbinols with primary alcohols has significant advantage of delivering higher‐order secondary alcohols in an economical, redox‐neutral fashion. In addition, the first enantioselective Guerbet reaction has also been achieved using a commercially available chiral ruthenium complex to deliver secondary alcohols with moderate yield and up to 92 % ee. In both reactions, the use of a traceless ketone promoter proved to be beneficial for the catalytic efficiency.
Nanocrystals Assembled by the Chemical Reaction of the Dispersion Solvent
Authors: Nakanishi Hideyuki , Kawabata Yuto , Tsujiai Shogo , Tanaka Hayato , Teraji Satoshi , Holló Gábor , Lagzi István , Norisuye Tomohisa , Tran‐Cong‐Miyata Qui
Published: April 2020

The development of methods to pattern nanocrystals with different sizes and shapes remains a challenge. In this study, we demonstrate a unique class of bottom‐up approaches to assemble nanocrystals into patterns. Our approach for patterning nanocrystals focuses on the utilization and control of the chemical reaction of solvents surrounding nanocrystals. The photopolymerization of solvent molecules through a photomask creates time‐dependent concentration gradients of the solvents. Dispersed nanocrystals such as silver nanowires (AgNWs) migrate and are gradually organized and integrated into the polymerizing films based on the concentration gradients. The AgNW‐embedded film properties are determined by the organized AgNW structures and include light transmission and electrical conductivity. Overall, the demonstrated method is very simple, widely applicable to various nanocrystals and solvents, and can thus contribute to the development of a new class of nanocrystal patterning methods.
Efficient Chemical Protein Synthesis using Fmoc‐Masked N‐Terminal Cysteine in Peptide Thioester Segments
Authors: Kar Abhisek , Mannuthodikayil Jamsad , Singh Sameer , Biswas Anamika , Dubey Puneet , Das Amit , Mandal Kalyaneswar
Published: April 2020

We report an operationally simple method to facilitate chemical protein synthesis by fully convergent and one‐pot native chemical ligations utilizing the fluorenylmethyloxycarbonyl (Fmoc) moiety as an N‐masking group of the N‐terminal cysteine of the middle peptide thioester segment(s). The Fmoc group is stable to the harsh oxidative conditions frequently used to generate peptide thioesters from peptide hydrazide or o‐aminoanilide. The ready availability of Fmoc‐Cys(Trt)‐OH, which is routinely used in Fmoc solid‐phase peptide synthesis, where the Fmoc group is pre‐installed on cysteine residue, minimizes additional steps required for the temporary protection of the N‐terminal cysteinyl peptides. The Fmoc group is readily removed after ligation by short exposure (<7 min) to 20 % piperidine at pH 11 in aqueous conditions at room temperature. Subsequent native chemical ligation reactions can be performed in presence of piperidine in the same solution at pH 7.
A Flexible Organic Single Crystal with Plastic‐Twisting and Elastic‐Bending Capabilities and Polarization‐Rotation Function
Authors: Liu Huapeng , Lu Zhuoqun , Tang Baolei , Qu Cheng , Zhang Zuolun , Zhang Hongyu
Published: April 2020

Flexible organic single crystals capable of plastic or elastic deformations have a variety of potential applications. Although the integration of plasticity and elasticity in a crystal is theoretically possible and it may cause rich and complex deformations which are highly demanded for potential applications, the integration is hard to realize in practice. Here, we show that through utilizing different modes of external forces for influencing molecular packing in different crystallographic directions, plastic helical twisting and elastic bending can both be achieved for a crystal, and they can even be realized simultaneously. Detailed crystallographic analyses and contrast experiments disclose the mechanisms behind these two kinds of distinct deformations and their mutual compatibility. Based on the plastically twistable nature of the crystal, a new application field of flexible organic single crystals, namely polarization rotators, is successfully opened up.
Designed Asymmetric Protein Assembly on a Symmetric Scaffold
Authors: Lemmens Lenne J. M. , Roodhuizen Job A. L. , de Greef Tom F. A. , Markvoort Albert J. , Brunsveld Luc
Published: April 2020

Cellular signaling is regulated by the assembly of proteins into higher‐order complexes. Bottom‐up creation of synthetic protein assemblies, especially asymmetric complexes, is highly challenging. Presented here is the design and implementation of asymmetric assembly of a ternary protein complex facilitated by Rosetta modeling and thermodynamic analysis. The wild‐type symmetric CT32–CT32 interface of the 14‐3‐3–CT32 complex was targeted, ultimately favoring asymmetric assembly on the 14‐3‐3 scaffold. Biochemical studies, supported by mass‐balance models, allowed characterization of the parameters driving asymmetric assembly. Importantly, our work reveals that both the individual binding affinities and cooperativity between the assembling components are crucial when designing higher‐order protein complexes. Enzyme complementation on the 14‐3‐3 scaffold highlighted that interface engineering of a symmetric ternary complex generates asymmetric protein complexes with new functions.
Unveiling the Local Structure of Palladium Loaded into Imine‐Linked Layered Covalent Organic Frameworks for Cross‐Coupling Catalysis
Authors: Romero‐Muñiz Ignacio , Mavrandonakis Andreas , Albacete Pablo , Vega Alicia , Briois Valérie , Zamora Félix , Platero‐Prats Ana E.
Published: April 2020

Layered covalent organic frameworks (2D‐COFs), composed of reversible imine linkages and accessible pores, offer versatility for chemical modifications towards the development of catalytic materials. Nitrogen‐enriched COFs are good candidates for binding Pd species. Understanding the local structure of reacting Pd sites bonded to the COF pores is key to rationalize interactions between active sites and porous surfaces. By combining advanced synchrotron characterization methods with periodic computational DFT modeling, the precise atomic structure of catalytic Pd sites attached to local defects is resolved within an archetypical imine‐linked 2D‐COF. This material was synthesized using an in situ method as a gel, under which imine hydrolysis and metalation reactions are coupled. Local defects formed in situ within imine‐linked 2D‐COF materials are highly reactive towards Pd metalation, resulting in active materials for Suzuki–Miyaura cross‐coupling reactions.
The structures and properties of bio‐based polyamide 56 fibers prepared by high‐speed spinning
Authors: Wang Yu , Kang Hong‐liang , Guo Ya‐fei , Liu Rui‐gang , Hao Xin‐min , Qiao Rong‐rong , Yan Jin‐long
Published: April 2020

Bio‐based polyamide 56 (PA56) fibers with the circular and trefoil cross‐sections were prepared by high‐speed spinning process. The pre‐oriented yarns (POY) and draw‐textured yarns (DTY) of PA56 were studied. The results showed that γ phase crystal dominated in POY with relative high degrees in the crystallinity and crystal orientation. In DTY, the drawing effect made the crystal transform from γ to α phase with the properties of the enhanced thickness of the crystal plate and the more order arranged molecules, that was the long period in these fibers was obviously increased to 7–8 nm. γ to α phase transition was much easy for PA56 fibers with circular cross‐section during drawing. PA56 fibers had excellent moisture absorption and release performances. They were easy to be dyed and had a good color fastness.
Low‐cost observations and experiments return a high value in plant phenology research
Authors: McDonough MacKenzie Caitlin , Gallinat Amanda S. , Zipf Lucy
Published: April 2020

Plant ecologists in the Anthropocene are tasked with documenting, interpreting, and predicting how plants respond to environmental change. Phenology, the timing of seasonal biological events including leaf‐out, flowering, fruiting, and leaf senescence, is among the most visible and oft‐recorded facets of plant ecology. Climate‐driven shifts in plant phenology can alter reproductive success, interspecific competition, and trophic interactions. Low‐cost phenology research, including observational records and experimental manipulations, is fundamental to our understanding of both the mechanisms and effects of phenological change in plant populations, species, and communities. Traditions of local‐scale botanical phenology observations and data leveraged from written records and natural history collections provide the historical context for recent observations of changing phenologies. New technology facilitates expanding the spatial, taxonomic, and human interest in this research by combining contemporary field observations by researchers and open access community science (e.g., USA National Phenology Network) and available climate data. Established experimental techniques, such as twig cutting and common garden experiments, are low‐cost methods for studying the mechanisms and drivers of plant phenology, enabling researchers to observe phenological responses under novel environmental conditions. We discuss the strengths, limitations, potential hidden costs (i.e., volunteer and student labor), and promise of each of these methods for addressing emerging questions in plant phenology research. Applied thoughtfully, economically, and creatively, many low‐cost approaches offer novel opportunities to fill gaps in our geographic, taxonomic, and mechanistic understanding of plant phenology worldwide.
Azulene in Polymers and Their Properties
Authors: Zeng Hui Ning , Png Zhuang Mao , Xu Jianwei
Published: April 2020

Azulene, a unique isomer of naphthalene, has received much interest from researchers in different fields due to its unusual chemical structure with a negatively charged 5‐membered ring fused with a positively charged 7‐membered ring. In particular, incorporation of azulene into polymers has led to many interesting properties. This minireview covers functionalization methods of azulene at its various positions of 5‐ and 7‐membered rings to form azulene derivatives including azulene monomers, and gives an overview of a wide range of azulene‐containing polymers including poly(1,3‐azulene), azulene‐based copolymers with connectivity at 1,3‐positions of the 5‐membered ring, or 4,7‐positions of the 7‐membered ring, as well as copolymers with azulene units as side chains. Their chemical and physical properties together with applications of azulene‐containing polymers have also been summarized.
The mean‐reverting 4/2 stochastic volatility model: Properties and financial applications
Authors: Escobar‐Anel Marcos , Gong Zhenxian
Published: April 2020

This article defines and studies a stochastic process that combines two important stylized facts of financial data: reversion to the mean, and a flexible generalized stochastic volatility process: the 4/2 process. This work is motivated by the modeling of at least two financial asset classes: commodities and volatility indexes. We provide analytical expressions for the conditional characteristic functions and closed‐form approximations to relevant cases, in particular a mean‐reverting Heston stochastic volatility model. Our results describe feasible changes of measure with the final aim of pricing financial derivatives. The empirical analysis and the estimation methodology confirm the need of such a model in several examples from the targeted asset classes. Applications to option pricing corroborate the substantial impact on the implied volatility surfaces of the new parameters.
Construction of the tetration distribution based on the continuous iteration of the exponential‐minus‐one function
Authors: Dijoux Yann
Published: April 2020

A new class of lifetime distributions, called tetration distribution, is presented based on the continuous iteration of the exponential‐minus‐one function. In particular, this distribution encompasses and extends the Weibull, Pareto, and Gompertz distributions. In addition, a characterization of the tail of the distribution is proposed through two indices, one of them encompassing the Pareto and Weibull tail indices. Finally, an inference procedure based on rank regression is implemented for the tetration distribution and applied to multiple datasets from the reliability field.
Synthesis and Characteristics of Pyrrolidinium‐Based Organic Ionic Plastic Crystals with Various Sulfonylamide Anions
Authors: Yoshizawa‐Fujita Masahiro , Yamada Hiromasa , Yamaguchi Shun , Zhu Haijin , Forsyth Maria , Takeoka Yuko , Rikukawa Masahiro
Published: April 2020

Organic ionic plastic crystals (OIPCs) have been studied as solid‐state electrolytes owing to their desirable properties such as plasticity, non‐flammability, and high ionic conductivity. However, the relationship between the ion structures and the properties of OIPCs are poorly understood. To supplement our previous work on the effects of the side chain structure of pyrrolidinium salts on their properties, this study examined the effects of the anion structure. For this purpose, five N,N‐diethylpyrrolidinium ([C2epyr]) salts with various sulfonylamide anions were synthesized. The [C2epyr] salts with bis(fluorosulfonyl)amide ([FSA]) and bis(pentafluoroethanesulfonyl)amide ([BETA]) exhibited higher ionic conductivity values at room temperature than the other [C2epyr] salts. The 1H and 19F solid‐state NMR results indicated that the component ions in [C2epyr][FSA] and [C2epyr][BETA] exhibited high rotational mobility, even in the solid state. Thus, rotational mobility is likely important for achieving high ionic conductivity.
Endogenous carbohydrate esterases of Clostridium thermocellum are identified and disrupted for enhanced isobutyl acetate production from cellulose
Authors: Seo Hyeongmin , Nicely Preston N. , Trinh Cong T.
Published: April 2020

Medium‐chain esters are versatile chemicals with broad applications as flavors, fragrances, solvents, and potential drop‐in biofuels. Currently, these esters are largely produced by the conventional chemical process that uses harsh operating conditions and requires high energy input. Alternatively, the microbial conversion route has recently emerged as a promising platform for sustainable and renewable ester production. The ester biosynthesis pathways can utilize either lipases or alcohol acyltransferase (AAT), but the AAT‐dependent pathway is more thermodynamically favorable in an aqueous fermentation environment. Even though a cellulolytic thermophile Clostridium thermocellum harboring an AAT‐dependent pathway has recently been engineered for direct conversion of lignocellulosic biomass into esters, the production is not efficient. One potential bottleneck is the ester degradation caused by the endogenous carbohydrate esterases (CEs) whose functional roles are poorly understood. The challenge is to identify and disrupt CEs that can alleviate ester degradation while not negatively affecting the efficient and robust capability of C. thermocellum for lignocellulosic biomass deconstruction. In this study, by using bioinformatics, comparative genomics, and enzymatic analysis to screen a library of CEs, we identified and disrupted the two most critical CEs, Clo1313_0613 and Clo1313_0693, that significantly contribute to isobutyl acetate degradation in C. thermocellum. We demonstrated that an engineered esterase‐deficient C. thermocellum strain not only reduced ester hydrolysis but also improved isobutyl acetate production while maintaining effective cellulose assimilation.
Liver transplantation for unresectable colorectal liver metastases in patients and donors with extended criteria (SECA-II arm D study)
Authors: Smedman T M , Line P-D , Hagness M , Syversveen T , Grut H , Dueland S
Published: April 2020

Background

Patients with metastatic colorectal cancer receiving palliative chemotherapy have a 5-year survival rate of approximately 10 per cent. Liver transplantation using strict selection criteria in patients with colorectal cancer and unresectable liver-only disease will result in a 5-year survival rate of 56–83 per cent. The aim of this study was to evaluate survival of patients with colorectal liver metastases (CRLM) after liver transplantation using extended criteria for both patients and donors.

Methods

This was a prospective single-arm study. Patients with synchronous unresectable CRLM who were not suitable for arms A, B or C of the SEcondary CAncer (SECA) II study who had undergone radical resection of the primary tumour and received chemotherapy were included; they underwent liver transplantation with extended criteria donor grafts. Patients who had resectable pulmonary metastases were eligible for inclusion. The main exclusion criteria were BMI above 30 kg/m2 and liver metastases larger than 10 cm. Survival was estimated using Kaplan–Meier analysis.

Results

Ten patients (median age 54 years; 3 women) were included. They had an extensive liver tumour load with a median of 20 (range 1–45) lesions; the median size of the largest lesion was 59 (range 15–94) mm. Eight patients had (y)pN2 disease, six had poorly differentiated or signet ring cell-differentiated primary tumours, and five had primary tumour in the ascending colon. The median Fong clinical risk score was 3 (range 2–5) and the median Oslo score was 1 (range 1–4). The median plasma carcinoembryonic antigen level was 4·3 (range 2–4346) μg/l. Median disease-free and overall survival was 4 and 18 months respectively.

Conclusion

Patients with unresectable liver-only CRLM undergoing liver transplantation with extended patient and donor criteria have relatively short overall survival.
The trajectory of gait development in mice
Authors: Akula Shyam K. , McCullough Katherine B. , Weichselbaum Claire , Dougherty Joseph D. , Maloney Susan E.
Published: April 2020

Objective

Gait irregularities are prevalent in neurodevelopmental disorders (NDDs). However, there is a paucity of information on gait phenotypes in NDD experimental models. This is in part due to the lack of understanding of the normal developmental trajectory of gait maturation in the mouse.

Materials and methods

Using the DigiGait system, we have developed a quantitative, standardized, and reproducible assay of developmental gait metrics in commonly used mouse strains that can be added to the battery of mouse model phenotyping. With this assay, we characterized the trajectory of gait in the developing C57BL/6J and FVB/AntJ mouse lines.

Results

In both lines, a mature stride consisted of 40% swing and 60% stance in the forelimbs, which mirrors the mature human stride. In C57BL/6J mice, developmental trajectories were observed for stance width, paw overlap distance, braking and propulsion time, rate of stance loading, peak paw area, and metrics of intraindividual variability. In FVB/AntJ mice, developmental trajectories were observed for percent shared stance, paw overlap distance, rate of stance loading, and peak paw area, although in different directions than C57 mice. By accounting for the impact of body length on stride measurements, we demonstrate the importance of considering body length when interpreting gait metrics.

Conclusion

Overall, our results show that aspects of mouse gait development parallel a timeline of normal human gait development, such as the percent of stride that is stance phase and swing phase. This study may be used as a standard reference for developmental gait phenotyping of murine models, such as models of neurodevelopmental disease.
Role of Two Exceptional trans Adenylation Domains and MbtH‐like Proteins in the Biosynthesis of the Nonribosomal Peptide WS9324A from Streptomyces calvus ATCC 13382
Authors: Bernhardt Mirjam , Berman Stefanie , Zechel David , Bechthold Andreas
Published: April 2020

Nonribosomal peptide synthetases (NRPS) are organized in a modular arrangement. Usually, the modular order corresponds to the assembly of the amino acids in the respective peptide, following the collinearity rule. The WS9326A biosynthetic gene cluster from Streptomyces calvus shows deviations from this rule. Most interesting is the presence of two trans adenylation domains that are located downstream of the modular NRPS arrangement. Adenylation domains are responsible for the activation of their respective amino acids. In this study, we confirmed the involvement of the trans adenylation domains in WS9326A biosynthesis by performing gene knockout experiments and by observing the selective adenylation of their predicted amino acid substrates in vitro. We conclude that the trans adenylation domains are essential for WS9326A biosynthesis. Moreover, both adenylation domains are observed to have MbtH‐like protein dependency. Overall, we conclude that the trans adenylation domains are essential for WS9326A biosynthesis.
Outcomes of Impella‐supported high‐risk nonemergent percutaneous coronary intervention in a large single‐center registry
Authors: Azzalini Lorenzo , Johal Gurpreet S. , Baber Usman , Bander Jeffrey , Moreno Pedro R. , Bazi Lucas , Kapur Vishal , Barman Nitin , Kini Annapoorna S. , Sharma Samin K.
Published: April 2020

Objectives

We aimed to evaluate the early and one‐year outcomes of Impella‐supported high‐risk nonemergent percutaneous coronary intervention (PCI).

Background

The evidence for the use of mechanical circulatory support (MCS) devices in high‐risk nonemergent PCI is limited and nonconclusive.

Methods

We performed a single‐center retrospective study including all patients who underwent high‐risk nonemergent PCI supported by Impella 2.5/CP at our institution between January 2009 and June 2018. This patient population was propensity score matched with subjects undergoing PCI with no MCS. The primary endpoint was major adverse cardiac events (MACE: all‐cause death, myocardial infarction [MI], and target lesion revascularization) at one‐year follow‐up.

Results

Two‐hundred fifty patients undergoing Impella‐supported nonemergent PCI were matched to 250 controls. The two groups were well balanced in terms of clinical and angiographic characteristics. Left main PCI was performed more frequently among Impella‐supported patients (26% vs. 11%, p < .001), who also had numerically higher prevalence of rotational atherectomy use (44% vs. 37%, p = .10) and a higher number of vessels treated (1.8 ± 0.8 vs. 1.3 ± 0.6, p < .001), compared with controls. Impella‐supported patients suffered a higher incidence of periprocedural MI (14.0% vs. 6.4%, p = .005), major bleeding (6.8% vs. 2.8%, p = .04), and need for blood transfusions (11.2% vs. 4.8%, p = .008). However, at one‐year follow‐up there were no differences in the rates of MACE (31.2% vs. 27.4%, p = .78) or any of its individual components between Impella‐supported patients and controls.

Conclusions

Although Impella‐supported patients suffer a higher incidence of periprocedural adverse events (partially linked to more aggressive PCI), the incidence of one‐year MACE was similar between the Impella and control group.
Carbon Pathways, Sodium‐Sulphur Promotion and Identification of Iron Carbides in Iron‐based Fischer‐Tropsch Synthesis
Authors: Paalanen Pasi P. , Weckhuysen Bert M.
Published: April 2020

Fisher‐Tropsch Synthesis (FTS) is industrially used for converting a carbon‐containing feedstock, such as coal, natural gas, biomass, and municipal waste, via the production of synthesis gas (a mixture of CO+H2) into hydrocarbons. This review article focuses on Fe‐based FTS catalysis, thereby focusing on the process conditions available for steering the various carbon pathways from input CO and their associated reactions. We will also discuss the effects of alkali‐sulphur chemical promotion and the identification of the FTS reaction active Fe carbides, which are assigned with precise crystal structures and nomenclature. Each observed Fe carbide crystal structure is further assigned with corresponding Mössbauer Absorption Spectroscopy (MAS) hyperfine fields. The expected formation temperatures and experimental conditions for the identified Fe carbides encountered in FTS research, namely ϵ‐Fe3C, η‐Fe2C, χ‐Fe5C2, θ‐Fe3C and θ‐Fe7C3, are reviewed.
Synergistic Inhibitory Effect of Potassium Sodium Tartrate Tetrahydrate and Sodium Stannate Trihydrate on Self‐Corrosion of Aluminum in Alkaline Aluminum‐Air Batteries
Authors: Taeri Omid , Hassanzadeh Ali , Ravari Fateme
Published: April 2020

To promote the efficiency of aluminum‐air batteries, the present paper proposes using inhibitor for decreasing anodic corrosion; therefor, the self‐corrosion of pure aluminum sheet (PAS) in KOH (1 M) solution at different concentrations of two inhibitors; potassium sodium tartrate tetrahydrate (STT) and sodium stannate trihydrate (SST) has been investigated both individually and collectively. The characteristics of PAS were studied through electrochemical methods including Tafel polarization curves, electrochemical impedance spectroscopy (EIS), scanning electron microscopy (SEM), and energy‐dispersive X‐ray spectroscopy (EDS). The results indicate that inhibition efficiencies for both inhibitors (STT and SST) increased with a rise in concentration of the inhibitors reaching a maximum in one certain concentration called optimum concentration. The constant current discharge plots for the assembled prototype aluminum‐air battery were also obtained, further confirming the aforementioned results. Finally, the calculated anode efficiency results indicate that the addition of mix inhibitor into electrolyte demonstrates the highest impact compared with the others, which should be attributed to the significantly reduced self‐corrosion reaction.
Alkyl Chain Length‐ and Polymorph‐Dependent Photomechanochromic Fluorescence of Anthracene Photodimerization in Molecular Crystals: Role of the Lattice Stiffness
Authors: Kuo Cheng‐Zong , Hsu Li‐Yun , Chen Yu‐Shan , Goto Kenta , Maity Subhendu , Liu Yi‐Hung , Peng Shie‐Ming , Kong Kien Voon , Shinmyozu Teruo , Yang Jye‐Shane
Published: April 2020

Anthracene–pentiptycene hybrid systems 1‐Cn, where n refers to the number of carbon atoms in the linear alkyl chain, crystallize in three different polymorphs, denoted Y (yellow), G (green), and B (blue) forms in terms of the fluorescence color. While all Y‐form crystals show the same yellow‐to‐blue fluorescence color response to the photomechanical stress generated by the anthracene [4+4] photodimerization reaction, the four G forms exhibit distinct photomechanofluorochromism (PMFC): from green to blue for G‐1‐C4, to orange for G‐1‐C7, to red for G‐1‐C8, and to red then blue for G‐1‐C9, and the B forms show no photochromic activity. The intriguing RGB three‐color PMFC and abnormal topochemical reactivity of G‐1‐C9 are attributed to inherent softness of the crystal lattice.
Homochiral Covalent Organic Frameworks for Asymmetric Catalysis
Authors: Ma Hui‐Chao , Zou Jie , Li Xue‐Tian , Chen Gong‐Jun , Dong Yu‐Bin
Published: April 2020

Owing to their permanent porosity, highly ordered and extended structure, good chemical stability, and tunability, covalent organic frameworks (COFs) have emerged as a new type of organic materials that can offer various applications in different fields. Benefiting from the huge database of organic reactions, the required functionality of COFs can be readily achieved by modification of the corresponding organic functional groups on either polymerizable monomers or established COF frameworks. This striking feature allows homochiral covalent organic frameworks (HCCOFs) to be reasonably designed and synthesized, as well as their use as a unique platform to fabricate asymmetric catalysts. This contribution provides an overview of new progress in HCCOF‐based asymmetric catalysis, including design, synthesis, and their application in asymmetric organic synthesis. Moreover, major challenges and developing trends in this field are also discussed. It is anticipated that this review article will provide some new insights into HCCOFs for heterogeneous asymmetric catalysis and help to encourage further contributions in this young but promising field.
Self‐Metalation of Anchored Porphyrins on Atomically Defined Cobalt Oxide Surfaces: In situ Studies by Surface Vibrational Spectroscopy
Authors: Wähler Tobias , Schuster Ralf , Libuda Jörg
Published: April 2020

Metalation of anchored porphyrins is essential for their functionality at hybrid interfaces. In this work, we have studied the anchoring and metalation of a functionalized porphyrin derivative, 5‐(4‐carboxyphenyl)‐10,15,20‐triphenylporphyrin (MCTPP), on an atomically‐defined CoO(100) film under ultrahigh vacuum (UHV) conditions. We follow both the anchoring to the oxide surface and the self‐metalation by surface Co2+ ions via infrared reflection absorption spectroscopy (IRAS). At 150 K, MCTPP multilayer films adsorb molecularly on CoO(100) without anchoring to the surface. Upon heating to 195 K, the first layer of porphyrin molecules anchors via formation of a bridging surface carboxylate. Above 460 K, the MCTPP multilayer desorbs and only the anchored monolayer resides on the surface up to temperatures of 600 K approximately. The orientation of anchored MCTPP depends on the surface coverage. At low coverage, the MCTPP adopts a nearly flat‐lying geometry, whereas an upright standing film is formed near the multilayer coverage. Self‐metalation of MCTPP depends critically on the surface temperature, the coverage and on the molecular orientation. At 150 K, metalation is largely suppressed, while the degree of metalation increases with increasing temperature and reaches a value of around 60 % in the first monolayer at 450 K. At lower coverage higher metalation fractions (85 % and above) are observed, similar as for increasing temperature.
Effects of metal support interaction on dry reforming of methane over Ni/Ce‐Al2O3catalysts
Authors: Adamu Sagir , Bawah Abdul‐Rashid , Muraza Oki , Malaibari Zuhair , Hossain Mohammad M.
Published: April 2020

Dry (CO2) reforming of methane is conducted over two newly synthesized Ni20/Ce‐γAl2O3and Ni20/Ce‐meso‐Al2O3catalysts. The x‐ray diffraction (XRD) patterns indicated that Ni20/Ce‐meso‐Al2O3exhibits a better dispersion of nickel, while Ni20/Ce‐γAl2O3has larger amounts of nickel crystallites. The temperature programmed desorption (TPD) kinetics analysis indicated that Ni20/Ce‐meso‐Al2O3had a lesser metal‐support interaction than the Ni20/Ce‐γAl2O3. The thermal gravimetric analysis (TGA) indicated that the incorporation of ceria into the Al2O3matrix helps to stabilize Ni20/Ce‐meso‐Al2O3during dry reforming of methane. The temperature programmed reduction (TPR) indicated that the synthesized catalysts were sufficiently reducible below 750 °C. A fixed bed reactor evaluation (at 750 °C) showed that both catalysts can facilitate methane reforming to syngas with minimal coking throughout the 30 hours time‐on‐stream (TOS). However, Ni20/Ce‐meso‐Al2O3is more promising in terms of prolonged stability for dry reforming applications. Moreover, the syngas yield for Ni20/Ce‐γAl2O3is close to equilibrium prediction during the first 1 hour of reaction time.
Biological Characterization, Mechanistic Investigation and Structure‐Activity Relationships of Chemically Stable TLR2 Antagonists
Authors: Bermudez Marcel , Grabowski Maria , Murgueitio Manuela S. , Tiemann Markus , Varga Péter , Rudolf Thomas , Wolber Gerhard , Weindl Günther , Rademann Jörg
Published: April 2020

Toll‐like receptors (TLRs) build the first barrier in the innate immune response and therefore represent promising targets for the modulation of inflammatory processes. Recently, the pyrogallol‐containing TLR2 antagonists CU‐CPT22 and MMG‐11 were reported; however, their 1,2,3‐triphenol motif renders them highly susceptible to oxidation and excludes them from use in extended experiments under aerobic conditions. Therefore, we have developed a set of novel TLR2 antagonists (1–9) based on the systematic variation of substructures, linker elements, and the hydrogen‐bonding pattern of the pyrogallol precursors by using chemically robust building blocks. The novel series of chemically stable and synthetically accessible TLR2 antagonists (1–9) was pharmacologically characterized, and the potential binding modes of the active compounds were evaluated structurally. Our results provide new insights into structure‐activity relationships and allow rationalization of structural binding characteristics. Moreover, they support the hypothesis that this class of TLR ligands bind solely to TLR2 and do not directly interact with TLR1 or TLR6 of the functional heterodimer. The most active compound from this series (6), is chemically stable, nontoxic, TLR2‐selective, and shows a similar activity with regard to the pyrogallol starting points, thus indicating the variability of the hydrogen bonding pattern.
Harnessing semantic segmentation masks for accurate facial attribute editing
Authors: Chen Peng , Xiao Qi , Xu Jian , Dong Xiaoli , Sun Linjun , Li Weijun , Ning Xin , Wang Guojun , Chen Ziheng
Published: April 2020

In recent years, with the rapid development of adversarial learning technology, facial attribute editing has made great success in a number of areas. Realistic visual effect, invariant identity information, and accurate editing area are the three key issues of facial attribute editing. Unfortunately, most researches focus on the former two problems. However, lack of awareness of the accurate editing area in the task is the main reason for damaging attribute‐irrelevant details. To address this issue, this article proposes a novel facial attribute editing algorithm—a generative adversarial network (GAN) with semantic masks—from the perspective of editing location accuracy. By generating the mask with respect to attribute‐related areas, the semantic segmentation network can only constrain the manipulation in the target region while not harming any attribute‐irrelevant details. The GAN is then combined with the semantic segmentation network to formulate the entire framework, which is referred to as SM‐GAN. Extensive experiments on the public datasets CelebA and LFWA prove that the presented method can not only ensure that the attribute manipulation is realistic, but also allow attribute‐irrelevant regions to remain unchanged. Moreover, it can also simultaneously edit multiple facial attributes.
Identification and characterization of high‐yielding, short‐duration rice genotypes for tropical Asia
Authors: Won Phyo L. P. , Liu Hongyan , Banayo Niño P. M. , Nie Lixiao , Peng Shaobing , Islam Mohammad R. , Sta. Cruz Pompe , Collard Bertrand C. Y. , Kato Yoichiro
Published: April 2020

Previous efforts to increase the yield of tropical rice (Oryza sativa L.) have focused on medium‐duration varieties. However, there is increasing demand for high‐yielding short‐duration varieties that can adapt to intensified cropping systems and climate change. Our goal was to identify physiological traits associated with high yield in elite short‐duration genotypes suitable for tropical Asia. We conducted field experiments in five consecutive growing seasons at the International Rice Research Institute, the Philippines. We selected genotypes in the first two seasons, then performed a detailed characterization of the most promising genotypes in the following three seasons. Of the 50 advanced‐generation genotypes, three had consistently high yield and early maturity, with yields 11 to 38% higher than that of ‘IRRI104’ (‘IR50404‐57‐2‐2‐3’), a short‐duration variety that is widely grown in Southeast Asia. These genotypes were 20 to 32 cm taller than IRRI104. We found that for grain growth, low source capacity, defined as stem nonstructural carbohydrates at heading plus biomass accumulation after heading, was the major factor for the low yield of IRRI104. Although sink capacity (spikelets m−2 × grain weight) in the promising genotypes was comparable to that of IRRI104, they had a 25 to 53% higher source–sink ratio (source capacity/sink capacity) than IRRI104, which was attributed to larger leaf area and greater biomass accumulation during the grain‐filling stage. This result suggests that slight changes in plant development to promote height combined with increased leaf area around heading would improve the yield of short‐duration rice varieties in tropical Asia.
Influence of media exposure and Corporate Social Responsibility compliance on customer perception: The moderating role of Firm's reputation risk
Authors: Khan Hadi , Sukhotu Vatcharapol
Published: April 2020

This research tries to measure the direct effects of media exposure, Corporate Social Responsibility (CSR) compliance on customer perception; and, to analyze the moderating role of firm's reputation risk. Data is collected from sports manufacturing industry, Sialkot, Pakistan. Partial Least Squares Structural Equation Modeling technique was used for analysis. The results showed positive effects of firm's media exposure and CSR compliance on customer perception. This suggests that firms which maintain positive image in the media and consider contributing positively in society and doing business with ethics, they attract positive attitude of the customers towards products and firms as well. Moderating results show that interaction of firm's reputation further strengthens the effects of both media exposure and CSR initiatives on customer perception. Results also revealed the positive effects of firm's reputation risk on customer perception. The paper discusses implications of this research for the existing literature, practitioners, and policymakers.
PD‐L1 expression in cell‐blocks of non‐small cell lung cancer: The impact of prolonged fixation
Authors: Vigliar Elena , Iaccarino Antonino , Campione Severo , Campanino Maria R. , Clery Eduardo , Pisapia Pasquale , De Luca Caterina , Bellevicine Claudio , Malapelle Umberto , De Dominicis Gianfranco , Troncone Giancarlo
Published: April 2020

Introduction

In the selection of non‐small cell lung cancer (NSCLC) patients for immunotherapy, specimen processed as cell blocks (CBs) may be the only available material to assess PD‐L1 expression. Therefore, optimal CB preparation becomes paramount. In this context, here we assessed whether inadequate fixation time might be one of the pre‐analytical factors affecting PD‐L1 expression.

Methods

Ex vivo CBs from placental (n = 3) and NSCLC (n = 8) resection specimens were obtained. PD‐L1 staining was performed on CBs prepared at increasing fixation times (12 hours, 48 hours, 72 hours, 96 hours, 168 hours and 504 hours) using the companion diagnostic SP263 Assay and a validated 22C3 laboratory developed test (LDT). Staining intensity and percentage of positive cells were evaluated.

Results

All placental CBs showed moderate to strong PD‐L1 positivity in most cells, regardless of the fixation time. Likewise, the percentage of SP263‐stained NSCLC cells was similar at all fixation times except for one case, which showed less intense SP263 staining at 168 hours. Conversely, in 5/8 cases, the 22C3 LDT percentage of positive cells and staining intensity decreased at 168 hours and 504 hours.

Conclusions

Our results show that fixation time influences the performance of 22C3 LDT on CBs. Thus, we recommend that the fixation time of cytological materials be carefully checked, especially when PD‐L1 testing is delayed until the oncology request. Indeed, delays in tissue processing and paraffin embedding may lead to sub‐optimal performance of PD‐L1 staining on CBs.
Prominent oncocytic metaplasia in pleomorphic adenoma: A potential diagnostic pitfall
Authors: Ito Hiroko , Ishida Mitsuaki , Miyasaka Chika , Okano Kimiaki , Sandoh Kaori , Fujisawa Takuo , Iwai Hiroshi , Tsuta Koji
Published: April 2020

Pleomorphic adenoma (PA) is the most common salivary gland tumor. The cytological features of PA are well recognized, and its diagnosis is straightforward in most cases. Some metaplastic changes in PA are well known; however, occurrence of oncocytic metaplasia in PA is very rare. In this report, we describe the first cytological case of prominent oncocytic metaplasia in PA identified based on immunocytochemical analysis. We report the case of a 62‐year‐old Japanese female who presented with swelling of the left neck region. A fine‐needle aspiration cytologic examination was performed followed by surgical resection. The Papanicolaou smear revealed the presence of discohesive neoplastic cells in a myxoid background. These neoplastic cells had a relatively rich, granular cytoplasm, and round nuclei with moderate pleomorphism. Initial cytodiagnosis revealed carcinoma ex PA (CXPA). Immunocytochemical analysis showed that abundant mitochondria were present in the cytoplasm of these neoplastic cells. Histopathological examination of the resected tumor demonstrated proliferation of oncocytic neoplastic cells within a myxoid material and the presence of conventional PA components. A final diagnosis of prominent oncocytic metaplasia in PA was made. Oncocytic metaplasia showed nuclear atypia and pleomorphism; therefore, CXPA, which presents with severe nuclear atypia and necrotic background, must be differentiated from oncocytic metaplastic PA. Recognition of oncocytic metaplasia in PA is important for correct diagnosis.
The effect of intrauterine inflammation on mTOR signaling in mouse fetal brain
Authors: Dong Jie , Lei Jun , Elsayed Nada A. , Lee Ji Yeon , Shin Na , Na Quan , Chudnovets Anna , Jia Bei , Wang Xiaohong , Burd Irina
Published: April 2020

Fetuses exposed to an inflammatory environment are predisposed to long‐term adverse neurological outcomes. However, the mechanism by which intrauterine inflammation (IUI) is responsible for abnormal fetal brain development is not fully understood. The mechanistic target of rapamycin (mTOR) signaling pathway is closely associated with fetal brain development. We hypothesized that mTOR signaling might be involved in fetal brain injury and malformation when fetuses are exposed to the IUI environment. A well‐established IUI model was utilized by intrauterine injection of lipopolysaccharide (LPS) to explore the effect of IUI on mTOR signaling in mouse fetal brains. We found that microglia activation in LPS fetal brains was increased, as demonstrated by elevated Iba‐1 protein level and immunofluorescence density. LPS fetal brains also showed reduced neuronal cell counts, decreased cell proliferation demonstrated by low Ki67‐positive density, and elevated neuron apoptosis evidenced by high expression of cleaved Caspase 3. Furthermore, we found that mTOR signaling in LPS fetal brains was elevated at 2 hr after LPS treatment, declined at 6 hr and showed overall inhibition at 24 hr. In summary, our study revealed that LPS‐induced IUI leads to increased activation of microglia cells, neuronal damage, and dynamic alterations in mTOR signaling in the mouse fetal brain. Our findings indicate that abnormal changes in mTOR signaling may underlie the development of future neurological complications in offspring exposed to prenatal IUI.
Involvement of early embryonic miR‐409‐3p in the establishment of anxiety levels in female mice
Authors: Dickson David A. , Stohn Patrizia , Saavedra Rodriguez Lorena , Hernandez Arturo , Harrington Anne , Liaw Lucy , Feig Larry A.
Published: April 2020

Small RNA molecules in early embryos, delivered from sperm to zygotes upon fertilization, are required for normal mouse embryonic development. Even modest changes in the levels of sperm‐derived miRNAs appear to influence early embryos and subsequent development. For example, stress‐associated behaviors develop in mice after injection into normal zygotes sets of sperm miRNAs elevated in stressed male mice. Here, we implicate early embryonic miR‐409‐3p in establishing anxiety levels in adult female, but not male mice. First, we found that exposure of male mice to chronic social instability stress, which leads to elevated anxiety in their female offspring across at least three generations through the paternal lineage, elevates sperm miR‐409‐3p levels not only in exposed males, but also in sperm of their F1 and F2 male offspring. Second, we observed that while injection of a mimic of miR‐409‐3p into zygotes from mating control males was incapable of mimicking this effect in offspring derived from them, injection of a specific inhibitor of this miRNA led to the opposite, anxiolytic effect in female, but not male, and offspring. These findings imply that baseline miR‐409‐3p activity in early female embryos is necessary for the expression of normal anxiety levels when they develop into adult females. In addition, elevated embryo miR‐409‐3p activity, possibly as a consequence of stress‐induced elevation of its expression in sperm, may participate in, but may not be sufficient for, the induction of enhanced anxiety.
Coping strategies and stress‐induced natural killer cell redistribution in women with eating disorders
Authors: Vaz‐Leal Francisco J. , Ramos‐Fuentes María Isabel , Guisado‐Macías Juan Antonio , Espárrago‐Llorca Guadalupe , Redondo‐Rodríguez Celia , Bajo‐Cabello Beatriz , Rodríguez‐Santos Laura
Published: April 2020

Background

Patients with eating disorders (ED) are very sensitive and responsive to psychosocial stress. Stress response includes changes in immune cell distribution and may be modulated by the capability to cope with stressors. Thus, the present study sought to analyze the association between coping strategies and immune response (natural killer [NK] cell redistribution following psychosocial stress) in patients with anorexia nervosa (AN) and bulimia nervosa (BN) and healthy controls (HC).

Method

Twenty‐four AN patients, 29 BN patients, and 58 HC were studied. A multidimensional assessment tool, the COPE Inventory, was used to assess coping strategies. The number of NK cells was quantified in peripheral blood before and after the application of the Trier Social Stress Test (TSST). Potentially mediating variables, such as weight status, severity of eating pathology, depression, anxiety, and impulsivity were controlled.

Results

The three groups differed in intensity and direction of cell redistribution: The TSST was followed in BN patients by a significant decrease in the number of NK cells, whereas HC displayed a moderate decrease and AN a clear increase. Specific correlations between coping strategies and NK cell mobilization were found, especially in BN patients (positive for “planning” and negative for “substance abuse”).

Conclusion

Recognition and subsequent modification of the dysfunctional coping strategies used by patients with ED could contribute to improving their immune status, strengthening their resilience and increasing their ability to overcome the disease.