bluuebunny/crossref_metadata_2025 huggingface dataset:
Trapping of Transient Organolithium Compounds
Authors: Inoue Kengo , Okano Kentaro
Published: July 2020

Organolithium chemistry has been widely utilized in organic synthesis as a reliable tool for introducing various functional groups. The intrinsic high reactivity of organolithiums allows rapid chemical transformation; however, the transient organolithiums bearing an electrophilic moiety often cause the undesired reactions such as self‐dimerization, isomerization, and decomposition, which prevent further synthetic application. In this minireview, we classify the reactions involving the short‐lived organolithiums and focus on the recent progress in flow chemistry, which allows to trap the highly reactive organolithium species. In addition, this review includes other approaches using the related organometallic species that can be performed in a conventional batch reactor. To place the recent development of this field in perspective, the established strategies controlling the reactivities of the short‐lived organolithiums provide a short‐step, efficient, and protective group‐free synthesis of functionalized organic molecules in medicinal, agrochemical, and material chemistry.
Vibronic Dynamics of Photodissociating ICN from Simulations of Ultrafast X‐Ray Absorption Spectroscopy
Authors: Morzan Uriel N. , Videla Pablo E. , Soley Micheline B. , Nibbering Erik T. J. , Batista Victor S.
Published: July 2020

Ultrafast UV‐pump/soft‐X‐ray‐probe spectroscopy is a subject of great interest since it can provide detailed information about dynamical photochemical processes with ultrafast resolution and atomic specificity. Here, we focus on the photodissociation of ICN in the 1Π1 excited state, with emphasis on the transient response in the soft‐X‐ray spectral region as described by the ab initio spectral lineshape averaged over the nuclear wavepacket probability density. We find that the carbon K‐edge spectral region reveals a rich transient response that provides direct insights into the dynamics of frontier orbitals during the I−CN bond cleavage process. The simulated UV‐pump/soft‐X‐ray‐probe spectra exhibit detailed dynamical information, including a time‐domain signature for coherent vibration associated with the photogenerated CN fragment.
Bioinspired Supramolecular Packing Enables High Thermo‐Sustainability
Authors: Tao Kai , Tang Yiming , Rencus‐Lazar Sigal , Yao Yifei , Xue Bin , Gilead Sharon , Wei Guanghong , Gazit Ehud
Published: July 2020

Bottom‐up self‐assembled bioinspired materials have attracted increasing interest in a variety fields. The use of peptide supramolecular semiconductors for optoelectronic applications is especially intriguing. However, the characteristic thermal unsustainability limits their practical application. Here, we report the thermal sustainability of cyclo‐ditryptophan assemblies up to 680 K. Non‐covalent interactions underlie the stability mechanism, generating a low exciton‐binding energy of only 0.29 eV and a high thermal‐quenching‐activation energy of up to 0.11 eV. The contributing forces comprise predominantly of aromatic interactions, followed by hydrogen bonding between peptide molecules, and, to a lesser extent, water‐mediated associations. This thermal sustainability results in a temperature‐dependent conductivity of the supramolecular semiconductors, showing 93 % reduction of the resistance from 320 K to 440 K. Our results establish thermo‐sustainable peptide self‐assembly for heat‐sensitive applications.
Large and Emissive Crystals from Carbon Quantum Dots onto Interfacial Organized Templates
Authors: Xiong Rui , Zhang Xiaofang , Krecker Michelle , Kang Saewon , Smith Marcus J. , Tsukruk Vladimir V.
Published: July 2020

Here, we report template‐assisted assembly of emissive carbon quantum dot (CQD) microcrystals on organized cellulose nanocrystals templates at the liquid–air interface. This large‐scale assembly is facilitated by the complementary amphiphilic character of CQDs and cellulose nanocrystals in the organized nematic phase. The resulting large microcrystals up to 200 μm across show unusually high emission that is not observed for limited CQDs aggregates. The dense crystal packing of CQDs in the layered fashion suppresses local molecular rotations and vibrations, thus restricting the intermolecular energy transfer and corresponding quenching phenomena. The as‐prepared crystals are mechanically stable and can be exploited for recyclable catalysis, enabling applications beyond the individual nanoparticles or disordered aggregates. The ligand‐templated assembly can be used to diversify CQD crystal architectures to guide formation of fibers, microplates, and micro‐flowers.
High‐Capacity and Stable Li‐O2 Batteries Enabled by a Trifunctional Soluble Redox Mediator
Authors: Xiong Qi , Huang Gang , Zhang Xin‐Bo
Published: July 2020

Li‐O2 batteries with ultrahigh theoretical energy densities usually suffer from low practical discharge capacities and inferior cycling stability owing to the cathode passivation caused by insulating discharge products and by‐products. Here, a trifunctional ether‐based redox mediator, 2,5‐di‐tert‐butyl‐1,4‐dimethoxybenzene (DBDMB), is introduced into the electrolyte to capture reactive O2− and alleviate the rigorous oxidative environment of Li‐O2 batteries. Thanks to the strong solvation effect of DBDMB towards Li+ and O2−, it not only reduces the formation of by‐products (a high Li2O2 yield of 96.6 %), but also promotes the solution growth of large‐sized Li2O2 particles, avoiding the passivation of cathode as well as enabling a large discharge capacity. Moreover, DBDMB makes the oxidization of Li2O2 and the decomposition of main by‐products (Li2CO3 and LiOH) proceed in a highly effective manner, prolonging the stability of Li‐O2 batteries (243 cycles at 1000 mAh g−1 and 1000 mA g−1).
Total Synthesis of Cryptotrione
Authors: Lyu Mao‐Yun , Zhong Zhuliang , Lo Vanessa Kar‐Yan , Wong Henry N. C. , Peng Xiao‐Shui
Published: July 2020

The total synthesis of cryptotrione (1) was enabled by substrate‐controlled diastereoselective construction of the bicyclo[3.1.0]hexene framework through platinum‐catalyzed enyne cycloisomerization and Lewis acid induced polyene cyclization to construct the abietane‐type tricyclic diterpene skeleton. The stereogenic tertiary carbon center in the side chain was installed in a diastereodivergent manner by conjugate addition reactions.
Effect of annealing on morphologies and performances of hydroxypropyl methylcellulose/hydroxypropyl starch blends
Authors: Chen Ying , Liao Lisha , Liu Hongsheng , Wang Yanfei , Zhang Liang , Chen Ling , Yu Long
Published: July 2020

The morphologies and performances of the blends of hydroxypropyl methylcellulose (HPMC), which is a thermal gel, and hydroxypropyl starch (HPS), which is a cooling gel, provides a scientific model to understand the relationship between the microstructure and performance of the unique thermal/cooling gel system. The films based on these blends have been developed for various applications, such as food packaging and medicine capsules, mainly for improving processibility. The morphologies and performance of the blends strongly depend on annealing or storage conditions and time since they are neither miscible nor compatible. This work focuses on the effects of storage conditions and time on the morphologies and performance of the blend films. It was found that the morphologies of the blend system depend on temperature, moisture, and annealing time. Correspondently, the gas permeability and mechanical properties of the film were also environmentally and time dependent. When HPS is continuous phase, the annealing results in starch recrystallization, which increases rigidity. When HPMC is the continuous phase, the materials showed less moisture sensitivity. Starch recrystallization and phase separation, which resulted in microcracks on the surface of the films, are the main reasons for the reduction in gas barrier and elongation. This work will study these issues using scanning electron microscope, X‐ray diffraction, mechanical testing and establish their relationship.
Electrochemical synthesis and characterization of poly (o‐amino benzyl alcohol) and poly (o‐amino benzyl alcohol‐co‐o‐anisidine)
Authors: Yalçınkaya Süleyman , Çakmak Didem , Seymen Kübra , Demetgül Cahit
Published: July 2020

In this study; poly (o‐amino benzyl alcohol) and poly (o‐amino benzyl alcohol‐co‐o‐anisidine) copolymer films were electrochemically synthesized by cyclic voltammetry technique on the platinum electrode. The synthesis of copolymer films was achieved in various monomers feed ratio (o‐amino benzyl alcohol: o‐anisidine; 8:2, 1:1, 2:8) of o‐amino benzyl alcohol and o‐anisidine. Different solution types were tested in aqueous and non‐aqueous media, especially during the synthesis process, as the electrolyte medium. As a result of the experiments, it was determined that sulfuric acid solution was the most suitable solution for both homopolymer and copolymer film growth. Homopolymer and copolymer samples were characterized by FT‐IR, cyclic voltammetry (CV), SEM, digital images and TGA/DTA techniques. The CV, SEM and digital images results indicated that the solution which has high ratio of monomer is more effective in copolymer film synthesis mechanism. TGA results showed that the 1:1 copolymer film had higher thermal stability than the films at other monomer ratios. Also, electrochemical studies exhibited that the copolymer film in 1:1 ratio is partially more electrochemically stable than other copolymer films.
The chain microstructure and condensed structure of polyethylene resin used for Biaxially stretched film
Authors: Li Yu , Jiang Binbo , Li Wei , Wang Jingdai , Yang Yongrong
Published: July 2020

To explore the desirable chain structure and condensed structure of polyethylene used for biaxial stretching, the blends of two polyethylenes (PE1 and PE2) with different molecular weight and branch distribution were investigated. Their condensed structure including relaxation and crystallization behavior was studied by rheology, dynamic mechanical analysis (DMA), and non‐isothermal crystallization kinetics. And the chain microstructure was characterized by preparative temperature rising elution fractionation (P‐TREF), and successive self‐nucleation and annealing (SSA). It was demonstrated that the structural variables were not changing monotonically with the increment of the PE1 content. The longest relaxation time, lowest and less varied crystallization rate always appeared when the blend contained 15 wt% of PE1. This excellent structure was owing to the formation of more branches on the short chains, resulting in the uniform distribution of lamellae size and thus showing the widest biaxial stretchable temperature range (i.e., 8°C).
Effects of Gasdermin D in Modulating Murine Lupus and its Associated Organ Damage
Authors: Wang Xinghao , Blanco Luz P. , Carmona‐Rivera Carmelo , Nakabo Shuichiro , Pedersen Hege L. , Yu Zu‐Xi , Kaplan Mariana J.
Published: July 2020

Objective

Gasdermin D (GSDMD) is the key executioner of an inflammatory cell death mechanism known as pyroptosis. Recent reports have also implicated GSDMD in other mechanisms of cell death, including apoptosis, necroptosis, and NETosis. Given the role of dysregulated cell death in autoimmune syndromes such as systemic lupus erythematosus (SLE), this study was undertaken in a murine lupus model to investigate whether GSDMD plays a pathogenic role in systemic autoimmunity by promoting inflammatory cell death, leading to increased generation of nuclear autoantigens and autoantibodies.

Methods

An imiquimod‐induced model of SLE was tested in GSDMD−/− mice (n = 30), with wild‐type (WT) mice as controls (n = 34), on a C57BL/6 background. At the time of euthanasia, the mice were examined for serum autoantibodies, immune complex deposition, organ inflammation, immune dysregulation, and type I interferon responses. A model of pristane‐induced lung injury in GSDMD−/− mice (n = 7), with WT mice as controls (n = 10), was used to confirm the pulmonary phenotype. Regulation of various mechanisms of cell death by GSDMD was investigated in the mice.

Results

Unexpectedly, GSDMD−/− mice developed enhanced mortality, more severe renal and pulmonary inflammation, and exacerbated autoantibody production in response to imiquimod. Pulmonary involvement was also more severe in the absence of GSDMD in mice with pristane‐induced lung injury. Compared to WT mice, lack of GSDMD was associated with increased levels of circulating nuclear autoantigens (P < 0.01), anti–double‐stranded DNA autoantibodies (P < 0.01), tissue immune complex deposition (P < 0.05), expansion of myeloid cell subsets (P < 0.05), and enhanced B cell activation and plasma cell differentiation (P = 0.001). Moreover, in the absence of GSDMD, enhanced autoantigen generation was associated with increased local induction of cell death in vivo.

Conclusion

GSDMD negatively regulates autoantigen generation and immune dysregulation in response to tissue injury and may play previously unappreciated protective roles in systemic autoimmunity.
From institutional pressure to the sustainable development of firm: Role of environmental management accounting implementation and environmental proactivity
Authors: Chaudhry Naveed Iqbal , Amir Muhammad
Published: July 2020

The current study purposes to assess the impact of institutional pressures (coercive, mimetic, and normative) on environmental performance of the firm along with the mediation of implementation of environmental management accounting and moderation of environmental proactivity between them. Quantitative data are collected through structured questionnaire from 500 middle‐level and top‐level managers and owners of manufacturing firms of Pakistan. Data are analyzed through SPSS and AMOS in which structural equation modeling in performed to assess hypotheses. Findings show that coercive, mimetic, and normative pressures are significant derivers of environmental performance. It is further found that coercive, mimetic, and normative pressures significantly enhance the implementation of environmental management accounting, which in turn enhances the environmental performance of the firm. Furthermore, environmental proactivity is found to be a significant moderator between mimetic pressure and environmental performance while no moderation by environmental proactivity is confirmed in relationships of coercive pressure and normative pressure with environmental performance. The current findings are anticipated to assist practitioners in strategy development and execution to improve environmental performance of the firm and policymaking to control environmental impacts of businesses and improve environmental conditions in the country. The current study is the first one to empirically examine the moderating role of environmental proactivity and mediating role of execution of environmental management accounting between institutional pressures and environmental performance in context of Pakistan; so, it will open new areas of discussion and analysis for researchers in the domain of institutional theory.
RETRACTED: Puerarin 6″‐O‐xyloside suppressed HCC via regulating proliferation, stemness, and apoptosis with inhibited PI3K/AKT/mTOR
Authors: Li Long , Liu Jun‐Dong , Gao Guo‐Dong , Zhang Kai , Song Yu‐Wei , Li Hong‐Bo
Published: July 2020

Puerarin 6″‐O‐xyloside is a tumor suppressive derivate of Puerarin that is recently characterized as a lysine‐specific demethylase 6B inhibitor. Here we investigated the effects of Puerarin 6″‐O‐xyloside in hepatocellular carcinoma (HCC) cell lines SMMC‐7721 and HepG2. Cell viability, proliferation, stemness, protein expression, and autophagy were tested by CCK‐8, colony formation, sphere formation, western blotting, and LC3B GFP puncta per cell, respectively. Apoptosis, CD133‐positive cells, and JC‐1‐labeled mitochondrial membrane potential were measured by flow cytometry. The effects of Puerarin 6″‐O‐xyloside in vivo were explored in HepG2 xenograft mice. Puerarin 6″‐O‐xyloside inhibited cell viability, proliferation, and stemness, and promoted apoptosis in both SMMC‐7721 and HepG2 cells. Further experiments showed promoted autophagy and decreased mitochondrial membrane potential, and decreased expression of p‐PI3K, p‐AKT, and p‐mTOR in HepG2 cells. Co‐administration of 3‐MA with Puerarin 6″‐O‐xyloside obviously augmented these effects including inhibited protein expression of p‐PI3K, p‐AKT, and p‐mTOR, and inhibited proliferation, promoted apoptosis, and decreased stemness. In HepG2 xenograft mice, 100 mg/kg/d Puerarin 6″‐O‐xyloside significantly suppressed tumor growth, stemness, and apoptosis. In conclusion, our study indicated that Puerarin 6″‐O‐xyloside decreased cell viability, proliferation, and stemness, and promoted autophagy and mitochondria‐dependent apoptosis of HCC, at least partly through inhibiting PI3K/AKT/mTOR. These results highlighted Puerarin 6″‐O‐xyloside as a promising prodrug that could inhibit both PI3K/AKT/mTOR and epigenetic demethylation.
A Robust Conductive Polymer Network as a Multi‐Functional Binder and Conductive Additive for Supercapacitors
Authors: Na Ruiqi , Lu Nan , Li Leibo , Liu Yudong , Luan Jiashuang , Wang Guibin
Published: July 2020

This study develops a robust conductive polymer network as a multi‐functional binder and conductive additive for activated‐carbon‐based electrodes for supercapacitors. The robust conductive network is prepared by assembling water‐soluble electron‐conductive carboxylated polythiophene: (poly[3‐(potassium‐4‐butanoate) thiophene], PPBT) onto poly(ethylene glycol)‐block‐poly(propylene glycol)‐block‐poly(ethylene glycol) (PEG−PPG−PEG, 3P) chains through chemical crosslinking. The homogeneous PPBT‐3P crosslinked network facilitates the formation of continuous electron‐conducting bridges throughout the electrodes, consequently reducing the electrode resistance, bringing the electrode a relatively high electronic conductivity of approximately 175 S cm−1, which is nearly five times higher than the widely used electrode with PVDF binder/Super P systems. Moreover, the introduction of a robust crosslinked network into the activated‐carbon‐based electrode provides robust adhesion force and enhances the electrolyte wetting uptake ability between the active material components and current collector, thereby ensuring the integrity of the whole electrode under folding, device fabrication and cycling. As a result, the supercapacitor device applying this conductive network exhibits an ultra‐high specific capacitance of 184.7 F g−1 at 0.5 A g−1, and possesses energy densities of 46.7 Wh kg−1 as well as a long cycling stability (95.6 % capacitance retention) after 5,000 charge–discharge cycles, far superior to the supercapacitor with conventional PVDF binder and comparable to recently reported porous‐carbon‐based supercapacitors. All of these results guarantee that the novel conductive network can be a promising candidate for developing porous carbon electrodes in supercapacitors.
Sparse common and distinctive covariates regression
Authors: Park Soogeun , Ceulemans Eva , Van Deun Katrijn
Published: July 2020

Having large sets of predictors from multiple sources concerning the same observation units and the same criterion is becoming increasingly common in chemometrics. When analyzing such data, chemometricians often have multiple objectives: prediction of the criterion, variable selection, and identification of underlying processes associated to individual predictor sources or to several sources jointly. Existing methods offer solutions regarding the first two aims of uncovering the predictive mechanisms and relevant variables therein for a single block of predictor variables, but the challenge of uncovering joint and distinctive predictive mechanisms and the relevant variables therein in the multisource setting still needs to be addressed. To this end, we present a multiblock extension of principal covariates regression that aims to find the complex mechanisms in which several or single sources may be involved; taken together, these mechanisms predict an outcome of interest. We call this method sparse common and distinctive covariates regression (SCD‐CovR). Through a simulation study, we demonstrate that SCD‐CovR provides competitive solutions when compared with related methods. The method is also illustrated via an application to a publicly available dataset.
Conformational Sensing by a Mammalian Olfactory Receptor
Authors: Liu Min Ting , Na Mihwa , Li Yadi , Biscoe Mark R. , Ryan Kevin
Published: July 2020

To identify odors, the mammalian nose deploys hundreds of olfactory receptors (ORs) from the rhodopsin‐like class of the G protein‐coupled receptor superfamily. Odorants having multiple rotatable bonds present a problem for the stereochemical shape‐based matching process assumed to govern the sense of smell through OR–odorant recognition. We conformationally restricted the carbon chain of the odorant octanal to ask whether an OR can respond differently to different odorant conformations. By using calcium imaging to monitor signal transduction in sensory neurons expressing the mouse aldehyde OR, Olfr2, we found that the spatial position of the C7 and C8 carbon atoms of octanal, in relation to its −CHO group, determines whether an aliphatic aldehyde functions as an agonist, partial agonist or antagonist. Our experiments provide evidence that an odorant can manipulate an OR through its intrinsic conformational repertoire, in unexpected analogy to the photon‐controlled aldehyde manipulation observed in rhodopsin.
Transition‐Metal‐Mediated Functionalization of White Phosphorus
Authors: Hoidn Christian M. , Scott Daniel J. , Wolf Robert
Published: July 2020

Recently there has been great interest in the reactivity of transition‐metal (TM) centers towards white phosphorus (P4). This has ultimately been motivated by a desire to find TM‐mediated alternatives to the current industrial routes used to transform P4 into myriad useful P‐containing products, which are typically indirect, wasteful, and highly hazardous. Such a TM‐mediated process can be divided into two steps: activation of P4 to generate a polyphosphorus complex TM‐Pn, and subsequent functionalization of this complex to release the desired phosphorus‐containing product. The former step has by now become well established, allowing the isolation of many different TM‐Pn products. In contrast, productive functionalization of these complexes has proven extremely challenging and has been achieved only in a relative handful of cases. In this review we provide a comprehensive summary of successful TM‐Pn functionalization reactions, where TM‐Pn must be accessible by reaction of a TM precursor with P4. We hope that this will provide a useful resource for continuing efforts that are working towards this highly challenging goal of modern synthetic chemistry.
Escaping from Flatland: Stereoconvergent Synthesis of Three‐Dimensional Scaffolds via Ruthenium(II)‐Catalyzed Noyori–Ikariya Transfer Hydrogenation
Authors: Cotman Andrej Emanuel
Published: July 2020

Noyori–Ikariya‐type ruthenium(II)‐catalysts for asymmetric transfer hydrogenation (ATH) have been known for 25 years and have proved as a well‐behaved and user‐friendly platform for the synthesis of chiral secondary alcohols. A progress has been made in the past five years in understanding the asymmetric reduction of complex ketones, where up to four stereocenters can be controlled in a single chemical transformation. Intriguing multi‐chiral molecular architectures are therefore available in few well understood and robust synthetic steps from commercially available building blocks and possess handles for additional functionalization. The aim of this Review is to showcase the availability of three‐dimensional scaffolds and homochiral lead‐like compounds via ATH and inspire their direct use in drug discovery endeavors. Basic mechanistic insights are provided to demystify the stereo‐chemical outcomes, as well as examples of diastereoselective transformations of enantiopure alcohols to give a feeling of how these rigid non‐planar molecules can be further elaborated.
Fluorogenic Protein Probes with Red and Near‐Infrared Emission for Genetically Targeted Imaging**
Authors: Bachollet Sylvestre P. J. T. , Addi Cyril , Pietrancosta Nicolas , Mallet Jean‐Maurice , Dumat Blaise
Published: July 2020

Fluorogenic probes are important tools to image proteins with high contrast and no wash protocols. In this work, we rationally designed and synthesized a small set of four protein fluorogens with red or near‐infrared emission. The fluorophores were characterized in the presence of albumin as a model protein environment and exhibited good fluorogenicity and brightness (fluorescence quantum yield up to 36 %). Once conjugated to a haloalkane ligand, the probes reacted with the protein self‐labeling tag HaloTag with a high fluorescence enhancement (up to 156‐fold). The spectroscopic properties of the fluorogens and their reaction with HaloTag were investigated experimentally in vitro and with the help of molecular dynamics. The two most promising probes, one in the red and one in the near‐infrared range, were finally applied to image the nucleus or actin in live‐cell and in wash‐free conditions using fluorogenic and chemogenetic targeting of HaloTag fusion proteins.
Research on product color design decision driven by brand image
Authors: Zhang Xinxin , Yang Minggang , Su Jianning , Yang Wenjin , Qiu Kai
Published: July 2020

As one of the most important visual characteristics in a product system, color can arouse the user's emotional demands quickly. Due to the complexity of the user's emotional needs mining process, it can be expressed by color image adjectives. Meanwhile, product color trends that meet the user's emotional demands may help decision makers to anticipate a new market positioning and reduce the blindness in the product color design. In this study, the Gray theory combined with the Kansei engineering was used to mine the macro and microscopic factors in product color design decision process based on the product color brand image. The results showed that the constructed method could be used to guide the product color design that was to meet the user's emotional needs comprehensively and quickly. The method solved the problems that exist in the current product color trend prediction research and improved the accuracy of the correlation mining between product color design elements and brand image. Lastly, the color design of the mid‐range sedan was taken as an example to prove the feasibility of the research approach. This is a new attempt to guide product color design decisions in two aspects, one is known from the results of product color trends quantitative prediction, and the other one comes from the correlation calculation between product color design elements and brand image.
Towards Accurate Predictions of Proton NMR Spectroscopic Parameters in Molecular Solids
Authors: Dračínský Martin , Vícha Jan , Bártová Kateřina , Hodgkinson Paul
Published: July 2020

The factors contributing to the accuracy of quantum‐chemical calculations for the prediction of proton NMR chemical shifts in molecular solids are systematically investigated. Proton chemical shifts of six solid amino acids with hydrogen atoms in various bonding environments (CH, CH2, CH3, OH, SH and NH3) were determined experimentally using ultra‐fast magic‐angle spinning and proton‐detected 2D NMR experiments. The standard DFT method commonly used for the calculations of NMR parameters of solids is shown to provide chemical shifts that deviate from experiment by up to 1.5 ppm. The effects of the computational level (hybrid DFT functional, coupled‐cluster calculation, inclusion of relativistic spin‐orbit coupling) are thoroughly discussed. The effect of molecular dynamics and nuclear quantum effects are investigated using path‐integral molecular dynamics (PIMD) simulations. It is demonstrated that the accuracy of the calculated proton chemical shifts is significantly better when these effects are included in the calculations.
Metabarcoding unsorted kick‐samples facilitates macroinvertebrate‐based biomonitoring with increased taxonomic resolution, while outperforming environmental DNA
Authors: Pereira‐da‐Conceicoa Lyndall , Elbrecht Vasco , Hall Andie , Briscoe Andrew , Barber‐James Helen , Price Benjamin
Published: July 2020

While previous studies have highlighted the potential of DNA‐based methods for the biomonitoring of freshwater macroinvertebrates, a limited number have investigated homogenization of bulk samples that include debris, in order to reduce sample‐processing costs. This study explores the use of several DNA‐based survey methods for water quality and biodiversity assessment in South Africa, comparing morphological and molecular‐based identification of freshwater macroinvertebrates at the family level and the level of molecular operational taxonomic units (mOTUs). Seven sites were studied across three rivers with four different sample types collected per site: a standard SASS biomonitoring sample split into a picked sample (also used for morphological identification) and a leftover debris sample; a more intensive‐search comprehensive sample; and a filtered water eDNA sample. DNA‐based methods recovered higher diversity than morphology, but did not always recover the same taxa, even at the family level. Regardless of the differences in SASS taxon scores, most DNA‐based methods, except a few eDNA samples, returned the same water quality assessment category as the standard morphology‐based assessment. Homogenized comprehensive samples recovered more freshwater invertebrate diversity than all other methods, suggesting the standardized SASS method overlooks taxa. The eDNA samples recovered more diversity than any other method; however, 90% of the reads were nontarget and as a result eDNA recovered the lowest target (macroinvertebrate) diversity. However, eDNA did find some target taxa that all other methods failed to detect. This study shows that unsorted bulk samples have the potential to be used for water quality biomonitoring, providing higher diversity estimates for macroinvertebrates than either SASS picked or eDNA samples. These results also show the value of incorporating DNA‐based approaches into existing South African metrics, providing additional taxonomic resolution to develop more refined metrics for biodiversity management.
Rational Design of Titanium Carbide MXene Electrode Architectures for Hybrid Capacitive Deionization
Authors: Buczek Samantha , Barsoum Michael L. , Uzun Simge , Kurra Narendra , Andris Ryan , Pomerantseva Ekaterina , Mahmoud Khaled A. , Gogotsi Yury
Published: July 2020

Intercalation redox materials have shown great promise for efficient water desalination due to available faradaic gallery sites. Symmetric capacitive deionization (CDI) cells previously demonstrated using MXenes were often limited in their salt adsorption capacity (SAC) and voltage window of operation. In this study, current collector‐ and binder‐free Ti3C2Tx MXene electrode architectures are designed with porous carbon as the positive electrode to demonstrate hybrid CDI (HCDI) operation. Furthermore, MXene current collectors are fabricated by employing a scalable doctor blade coating technique and subsequently spray coating a layer of a small flake MXene dispersion. Hydrophilic redox‐active galleries of MXenes are capable of intercalating a variety of aqueous cations including Na+, K+, and Mg2+ ions, showing volumetric capacitances up to 250 F cm‐3. As a result, a salt removal capacity of 39 mg g‐1 with decent cycling stability is achieved. This study opens new avenues for developing freestanding, binder‐ and additive‐free MXene electrodes for HCDI applications.
Regiodivergent Late‐Stage Pd‐ or Ru‐Catalyzed C–H Bond Functionalization Applied to the Straightforward Synthesis of N‐Methylated Diflufenican Derivatives
Authors: Benhalouche Mohamed Elhadi , Li Haoran , Miloudi Abdellah , Benzai Amal , Cordier Marie , Soulé Jean‐François , Doucet Henri
Published: July 2020

The late‐stage C–H diversification methodology was applied to the preparation of arylated Diflufenican derivatives. Using a palladium catalyst associated with potassium pivalate, a regioselective arylation of the C–H bond flanked by the two fluorine atoms was observed. The reaction tolerated a wide range of useful functional groups on the aryl bromide. Conversely, the use of a ruthenium catalyst allowed to arylate the trifluoromethylbenzene ring of Diflufenican. To the best of our knowledge, these synthetic schemes are the first ones allowing the preparation of such arylated Diflufenican derivatives.
Computational fluid dynamics modeling of ibuprofen removal using a hollow fiber membrane contactor
Authors: Qatezadeh Deriss Ali , Langari Sepideh , Taherian Mostafa
Published: July 2020

In this study, modeling and simulation of removing a common pharmaceutical contaminant by a hollow fiber membrane contactor (HFMC) were carried out. For this purpose, a model was presented for separation of ibuprofen from wastewater in the membrane contactor. The suggested model was developed by coupling the mass and momentum equations. The partial differential equations (PDEs) and the corresponding boundary conditions of the model were solved using the computational fluid dynamics (CFD) techniques. The results showed that the predictions of this model were in close agreement with experimental data obtained from the literature. Moreover, the effects of different design and operating parameters on the removal of ibuprofen were studied. The simulation results revealed that the removal of ibuprofen was increased by increasing the membrane porosity and the length of fibers. The ibuprofen removal efficiency was also enhanced up to 93.2 and 90.2% by increasing the inner radius and the number of fibers from 110 to 145μm and 3,000 to 15,000, respectively. As a result, this study illustrates the successful development of the CFD model for prediction of ibuprofen removal using HFMC according to which removal efficiency of more than 95% was achieved.
Oxidation kinetics of water contaminants: New insights from artificial intelligence
Authors: Keivanimehr Farhad , Baghban Alireza , Habibzadeh Sajjad , Mohaddespour Ahmad , Esmaeili Amin , Tajammal Munir Muhammad , Saeb Mohammad Reza
Published: July 2020

Degradation of water contaminants through the advanced oxidation processes (AOP) has become the focus of strategists of environmental science and technology. Hydroxyl radicals are regarded as promising oxidants for the efficient decomposition of the organic contaminants. Nevertheless, understanding and monitoring the kinetics of the hydroxyl radical reaction has remained cumbersome to be deciphered by the aid of mathematical and statistical analyses. Herein, a new stochastic gradient boosting (SGB) decision tree technique based on the quantitative structure–property relationship (QSPR) method was developed to model and capture an image of the degradation rate constant of the hydroxyl radicals. An artificial model was constructed, trained, and tested on the bedrock of 457 different cases of water contaminants from 27 chemical structures. Several statistical techniques, including outlier detection, regression, sensitivity, and error analyses were served to validate the reliability of the proposed model. The outcomes showed that the developed model could appropriately estimate the logarithmic hydroxyl radical rate constants of numerous water contaminants with the promising R‐squared of 0.97, and a quite low mean absolute relative error of 0.86%. Moreover, a sensitivity analysis revealed that Burden eigenvalue was found to be the most effective parameter as the input of the model. Finally, a comparison study was performed between the proposed QSPR and the models previously suggested, where the superiority of the present model was uncovered.
Exergy analysis of hydrogen production from manipueira biogas
Authors: Madeira Jonni Guiller Ferreira , de Oliveira Elizabeth Mendes , Springer Marcus Val , da Conceição Layla Theodoro , Delgado Angel Ramon Sanchez
Published: July 2020

The use of hydrogen as clean energy has been becoming more attractive, because it is the most abundant element in the universe, the lightest fuel and richest in energy per unit mass. Cassava is a commodity of great importance in several underdeveloped countries, where its products and by‐products are of great importance in the food chain of these nations. Thus, the possibility of produce hydrogen from cassava wastewater (manipueira) not only recover the energy contained in cassava wastes but also eliminate most of the hydrocyanic acid contamination problems. The aim of this study is to perform the exergy analysis of hydrogen production by steam reforming from different biogases and analyze the hydrogen production in many different scenarios, showing that cassava wastewater has great potential for hydrogen production. Four different types of methane concentration were studied: 70.25, 75.5, 80.9, and 97.14%. The exergy analysis of the process and the production of hydrogen were calculated through simulation of the process using HYSYS software version 8.0. The results from these analyzes showed this is an alternative environmentally attractive and adding values to the cassava supply chain.
A principal component approach to improve association testing with polygenic risk scores
Authors: Coombes Brandon J. , Ploner Alexander , Bergen Sarah E. , Biernacka Joanna M.
Published: July 2020

Polygenic risk scores (PRSs) have become an increasingly popular approach for demonstrating polygenic influences on complex traits and for establishing common polygenic signals between different traits. PRSs are typically constructed using pruning and thresholding (P+T), but the best choice of parameters is uncertain; thus multiple settings are used and the best is chosen. Optimization can lead to inflated Type I error. Permutation procedures can correct this, but they can be computationally intensive. Alternatively, a single parameter setting can be chosen a priori for the PRS, but choosing suboptimal settings results in loss of power. We propose computing PRSs under a range of parameter settings, performing principal component analysis (PCA) on the resulting set of PRSs, and using the first PRS–PC in association tests. The first PC reweights the variants included in the PRS to achieve maximum variation over all PRS settings used. Using simulations and a real data application to study PRS association with bipolar disorder and psychosis in bipolar disorder, we compare the performance of the proposed PRS–PCA approach with a permutation test and an a priori selected p‐value threshold. The PRS–PCA approach is simple to implement, outperforms the other strategies in most scenarios, and provides an unbiased estimate of prediction performance.
Next‐Generation Immunosequencing Reveals Pathological T‐Cell Architecture in Autoimmune Hepatitis
Authors: Schultheiß Christoph , Simnica Donjete , Willscher Edith , Oberle Anna , Fanchi Lorenzo , Bonzanni Nicola , Wildner Nils H. , Schulze Zur Wiesch Julian , Weiler‐Normann Christina , Lohse Ansgar W. , Binder Mascha
Published: July 2020

Background and Aims

Autoimmune hepatitis (AIH) is a chronic liver disease that regularly relapses when immunosuppression is tapered. It is thought to be driven by T‐cells, whereas the etiologic impact of an apparently deregulated B lineage system, as evidenced by hypergammaglobulinemia and autoantibodies, remains elusive. We set out to investigate T and B cell repertoires supporting chronic inflammation in AIH.

Approach and Results

T and B cell receptor (TCR/BCR) and human leukocyte antigen (HLA) next‐generation immunosequencing were used to record immune signatures from a cohort of 60 patients with AIH and disease controls. Blood and liver B lineage immune metrics were not indicative of a dominant directional antigen selection apart from a slight skewing of IGHV
‐J genes. More importantly, we found strong AIH‐specific TRBV‐J skewing not attributable to the HLA‐DRB1 specificities of the cohort. This TCR repertoire bias was generated as a result of peripheral T cell (de)selection and persisted in disease remission. Using a clustering algorithm according to antigenic specificity, we identified liver TCR clusters that were shared between patients with AIH but were absent or deselected in patients with other liver pathologies.

Conclusions

Patients with AIH show profound and persisting T‐cell architectural changes that may explain high relapse rates after tapering immunosuppression. Liver T‐cell clusters shared between patients may mediate liver damage and warrant further study.
Synthesis and Biological Evaluation of Iodinated Fidaxomicin Antibiotics
Authors: Dorst Andrea , Shchelik Inga S. , Schäfle Daniel , Sander Peter , Gademann Karl
Published: July 2020

Fidaxomicin (1, tiacumicin B, lipiarmycin A3) is a marketed antibiotic that is used in the treatment of Clostridium difficile infections. Based on the analysis of a cryo‐EM structure of fidaxomicin binding to its target enzyme (RNA‐polymerase), a cation‐π interaction of the aromatic moiety with an arginine residue was identified. Therefore, the variation of the substituents and concurrently changing the electronic properties of the aryl moiety represents an interesting strategy in the search for new fidaxomicin analogs. Herein, we report the first semisynthetic access to new fidaxomicin analogs with varying halogen substituents through a Pd‐catalyzed hydrodechlorination reaction. Subsequent iodination gave access to the first iodo‐fidaxomicin derivatives, which matched or improved antibacterial properties compared to fidaxomicin against Mycobacterium tuberculosis and Staphylococcus aureus ATCC 29213.
Investigating the effect of various fin geometries on the thermal performance of a heat sink under natural convection
Authors: Hameed Vinous M. , Hussein Maha A. , Dhaiban Hussein T.
Published: July 2020

Experimentally investigates heat dissipation by different longitudinal fins fitted to a cylindrical heat sink under natural convection conditions. Five aluminum fin configurations at base temperatures (70°C, 85°C, 100°C, and 115°C) were studied. The first fin was plain (fin1), while   second fin had a triangular edge (fin2). The rest fins have the same triangular edge but with six 1cm circular perforations near the edge (fin3). While the perforations in fin4 were in the middle longitudinal fin length. The last fin (fin5) had twelve 0.5 cm circular perforations distributed into two columns. The measurements were validated with theoretical correlation with an acceptable deviation. The results showed that fin2, fin3, fin4, and fin5 dissipate more heat by 2.4%, 8.7%, 11.4%, and 5% than the flat fin with 9.8%, 11.85%, 11.85%, and 10.82% weight reduction, respectively. The heat transfer coefficient enhanced by 7.98%, 16.81%, 12.35%, and 5.44% for fin5, fin4, fin3, and fin2, respectively. Large circular perforation was more effective to dissipate heat especially when located near the heat source as in fin4 which gives the best heat dissipation with more weight reduction. The proposed fins efficiency were greater than 92%.
Effects of rotor angle and time after centrifugation on the biological in vitro properties of platelet rich fibrin membranes
Authors: Lourenço Emanuelle Stellet , Alves Gutemberg Gomes , de Lima Barbosa Renata , Spiegel Carolina Nascimento , de Mello‐Machado Rafael Coutinho , Al‐Maawi Sarah , Ghanaati Shahram , de Almeida Barros Mourão Carlos Fernando
Published: July 2020

This study evaluated the impact of rotor angle and time of storage after centrifugation on the in vitro biological properties of platelet‐rich fibrin (PRF) membranes. Blood samples (n = 9) were processed with a vertical fixed‐angle (V) or a swing‐out horizontal (H) centrifuge, with 20–60 min of sample storage after centrifugation. Leukocytes, platelets, and red blood cells were counted, and fibrin architecture was observed by scanning electron microscopy (SEM). The release of FGF2, PDGFbb, VEGF, IL‐6, and IL‐1β was measured after incubation on culture media for 7–21 days. Cell content was equivalent in all experimental groups (p > .05). The fibrin matrix was similar for fixed‐angle and horizontal centrifugation. Horizontal centrifugation induced a twofold increase in PDGF and 1.7× increase on FGF release as compared to V samples, while IL‐1β was significantly reduced (p < .05). No significant difference was observed on the release of growth factors and cytokines at different times after centrifugation (p < .05). These data suggest that both angles of centrifugation produce PRF membranes with similar structure and cellularity, but horizontal centrifugation induces a higher release of growth factors. Higher times of storage after centrifugation did not impact on cell content and the release of growth factors.
Identification of biomarkers correlated with diagnosis and prognosis of endometrial cancer using bioinformatics analysis
Authors: Zhao Huishan , Jiang Aihua , Yu Mingwei , Bao Hongchu
Published: July 2020

Endometrial cancer (EC) is one of the most common malignancies in the female genital system, characterized by high mortality and recurrence rates. This study attempted to screen key genes and potential prognostic biomarkers for EC using bioinformatics analysis. Twenty‐seven normal endometrial tissues and 135 EC samples were collected from four Gene Expression Omnibus (GEO) databases, then we identified the differentially expressed genes (DEGs) and conducted downstream analyses. Moreover, we screened hub genes by constructing a protein‐protein interaction (PPI) network. Finally, we assessed the prognostic values and molecular mechanism of the potential prognostic genes using the Kaplan‐Meier curve and Gene Set Enrichment Analysis (GSEA). As a result, 28 upregulated and 94 downregulated genes were determined after gene integration of these four GEO data sets. Gene Ontology analysis indicated that DEGs were mainly involved in transcriptional regulation and cell proliferation. The Kyoto Encyclopedia of Gene and Genome pathway analysis primarily related to transcriptional misregulation and apoptosis. Moreover, the PPI analysis revealed 10 hub genes (JUN, UBE2I, GATA2, WT1, PIAS1, FOXL2, RUNXI, EZR, TCF4, and NR2F2) with a high degree of connectivity, among them, the expression tendency of nine genes except UBE2I were consistent with messenger RNA level from The Cancer Genome Atlas data. Furthermore, only FOXL2, TCF4, and NR2F2 were significantly correlated with prognosis of EC patients, and their low expression associated biological pathways were enriched in the cell cycle and fatty acid metabolism. In conclusion, this study identified three key genes as biomarkers and potential therapeutic targets of EC on the basis of integrated bioinformatics analysis. The findings will improve our comprehension of the molecular mechanisms underlying the pathogenesis and prognosis of EC.