bluuebunny/crossref_metadata_2025 huggingface dataset:
The expanding Asgard archaea and their elusive relationships with Eukarya
Authors: Da Cunha Violette , Gaïa Morgan , Forterre Patrick
Published: March 2022

The discovery of Asgard archaea and the exploration of their diversity over the last 6 years have deeply impacted the scientific community working on eukaryogenesis, rejuvenating an intense debate on the topology of the universal tree of life (uTol). Here, we discuss how this debate is impacted by two recent publications that expand the number of Asgard lineages and eukaryotic signature proteins (ESPs). We discuss some of the main difficulties that can impair the phylogenetic reconstructions of the uTol and suggest that the debate about its topology is not settled. We notably hypothesize the existence of horizontal gene transfers between ancestral Asgards and proto‐eukaryotes that could result in the observed abnormal behaviors of some Asgard ESPs and universal marker proteins. This hypothesis is relevant regardless of the scenario considered regarding eukaryogenesis. It implies that the Asgards were already diversified before the last eukaryotic common ancestor and shared the same biotopes with proto‐eukaryotes. We suggest that some Asgards might be still living in symbiosis today with modern Eukarya.
“Life is short, and art is long”: RNA degradation in cyanobacteria and model bacteria
Authors: Zhang Ju‐Yuan , Hess Wolfgang R. , Zhang Cheng‐Cai
Published: March 2022

RNA turnover plays critical roles in the regulation of gene expression and allows cells to respond rapidly to environmental changes. In bacteria, the mechanisms of RNA turnover have been extensively studied in the models Escherichia coli and Bacillus subtilis, but not much is known in other bacteria. Cyanobacteria are a diverse group of photosynthetic organisms that have great potential for the sustainable production of valuable products using CO2 and solar energy. A better understanding of the regulation of RNA decay is important for both basic and applied studies of cyanobacteria. Genomic analysis shows that cyanobacteria have more than 10 ribonucleases and related proteins in common with E. coli and B. subtilis, and only a limited number of them have been experimentally investigated. In this review, we summarize the current knowledge about these RNA‐turnover‐related proteins in cyanobacteria. Although many of them are biochemically similar to their counterparts in E. coli and B. subtilis, they appear to have distinct cellular functions, suggesting a different mechanism of RNA turnover regulation in cyanobacteria. The identification of new players involved in the regulation of RNA turnover and the elucidation of their biological functions are among the future challenges in this field.
MomL inhibits bacterial antibiotic resistance through the starvation stringent response pathway
Authors: Dou Qin , Yuan Jin , Yu Rilei , Yang Jiahui , Wang Jiayi , Zhu Yuxiang , Zhong Jing , Long Hongan , Liu Zhiqing , Wang Xianghong , Li Yuying , Xiao Yichen , Liang Jiazhen , Zhang Xiao‐Hua , Wang Yan
Published: March 2022

Antibiotic resistance in gram‐negative pathogens has become one of the most serious global public health threats. The role of the N‐acyl homoserine lactone (AHL)‐mediated signaling pathway, which is widespread in gram‐negative bacteria, in the bacterial resistance process should be studied in depth. Here, we report a degrading enzyme of AHLs, MomL, that inhibits the antibiotic resistance of Pseudomonas aeruginosa through a novel mechanism. The MomL‐mediated reactivation of kanamycin is highly associated with the relA‐mediated starvation stringent response. The degradation of AHLs by MomL results in the inability of LasR to activate relA, which, in turn, stops the activation of downstream rpoS. Further results show that rpoS directly regulates the type VI secretion system H2‐T6SS. Under MomL treatment, inactivated RpoS fails to regulate H2‐T6SS; therefore, the expression of effector phospholipase A is reduced, and the adaptability of bacteria to antibiotics is weakened. MomL in combination with kanamycin is effective against a wide range of gram‐negative pathogenic bacteria. Therefore, this study reports a MomL‐antibiotic treatment strategy on antibiotic‐resistant bacteria and reveals its mechanism of action.
Existence and stability of a steady state for a coupled system of elliptic equation modelling the biodenitrification process
Authors: Abaali Mostafa
Published: March 2022

The process of biodegradation requires the success of bacteria to colonize the reactor. In this work, we will give a sufficient condition, which is the minimum amount of nutrient that must be injected into the reactor for the bacteria to evolve, for the existence and stability of a steady state other than the washout steady state, for a coupled system of partial differential equations (PDE) modelling the bio‐denitrification process. The existence of a weak steady state is showed contrary to what is done for the ordinary differential equation (ODE) because our system consists of a coupled partial differential equations (PDE). The stability of this steady state depends on the stability of the washout steady state which is, more or less, easy to study.
Dual‐wideband dual‐polarized rhombic antenna array for base‐station applications
Authors: Ye Liang Hua , Li Yuan Jun , Li Jian‐Feng , Hu Zhenxin , Zhang Gary , Zhang Xiu Yin
Published: March 2022

A compact dual‐wideband dual‐polarized antenna array with a narrow beam and low side‐lobe level for indoor base‐station applications is presented. Four higher‐band dipole elements are inserted inside four lower‐band rhombic‐arranged dipole elements. Dipole elements for each band are excited by two 1‐to‐4 power dividers with equal magnitude and phase. By using this scheme, stable narrow radiation patterns with low side‐lobe levels both in the horizontal and vertical planes are obtained over the dual‐frequency bands. For verification, a dual‐wideband rhombic antenna array with bandwidths of 49.3% (0.64–1.06 GHz) and 52.3% (1.61–2.75 GHz) for VSWR < 1.5 is designed. It has a stable radiation pattern with 3‐dB beamwidths of around 33° and low side‐lobe levels of less than −22 dB both in the horizontal and vertical planes.
Development of a Monte Carlo Random Walk Model for the Prediction of Linear and Branched Polymer Configuration and Connection to Radius of Gyration and GPC‐MALS Experimental Results
Authors: Touloupidis Vasileios , Albrecht Andreas
Published: March 2022

In this work, a self‐avoiding Monte‐Carlo off‐lattice 3D random walk model that is able to predict the configuration of linear and branched carbon‐based macromolecules, taking into account: i) the bond length, ii) the carbon‐carbon angle, and, iii) steric interferences, is presented. The methodology follows the theoretical framework proposed by the pioneering work of P. J. Flory. The Monte‐Carlo model developed is being validated based on experimental results of radius of gyration coming from linear polyethylene characterization by size exclusion chromatography multiangle light scattering (SEC‐MALS) technique. The most detailed version of the model manages to reach an accuracy level of 80% with regard to radius of gyration, without any tuning procedure involved. Furthermore, considering the solvent effect, the accuracy level reaches a value of 95%. On the contrary, it is shown that the simplest Monte Carlo random walk model version (including only the bond length restriction) is not able to quantitatively predict the experimentally acquired values of radius of gyration. Moreover, the developed Monte Carlo model is further employed to predict the expected radius of gyration values of more complex branched topologies, demonstrating the potential of this work.
Amide proton transfer imaging in stroke
Authors: Heo Hye‐Young , Tee Yee Kai , Harston George , Leigh Richard , Chappell Michael A.
Published: March 2022

Amide proton transfer (APT) imaging, a variant of chemical exchange saturation transfer MRI, has shown promise in detecting ischemic tissue acidosis following impaired aerobic metabolism in animal models and in human stroke patients due to the sensitivity of the amide proton exchange rate to changes in pH within the physiological range. Recent studies have demonstrated the possibility of using APT‐MRI to detect acidosis of the ischemic penumbra, enabling the assessment of stroke severity and risk of progression, monitoring of treatment progress, and prognostication of clinical outcome. This paper reviews current APT imaging methods actively used in ischemic stroke research and explores the clinical aspects of ischemic stroke and future applications for these methods.
Preparation of Cerium‐Bismuth Oxide Catalysts for Diesel Soot Oxidation Including Evaluation of an Automated Soot‐Catalyst Contact Mode
Authors: Hebert Sabrina Christina , Stöwe Klaus
Published: March 2022

Cerium‐bismuth oxides have emerged as promising candidates for Diesel soot oxidation. The catalysts are synthesized via automated co‐precipitation methods. T50 values, where 50 % of soot is oxidized, and the dynamic oxygen storage capacity (OSCdyn) are used to compare the catalytic activity. The activity is measured by thermogravimetric methods. The synthesized catalysts are characterized through powder X‐ray diffraction (PXRD), Raman spectroscopy, and specific surface area (SBET) measurements. This work investigates the influence of the contact mode between soot and catalyst. The literature‐known manual contact modes “loose”, “tight”, and “wet” are compared with our developed automated contact mode, using a dual asymmetric centrifuge. The rotation speed rs and mixing time tM have been varied independently. Both factors influence the T50 value. A continuous transition from loose to tight contact mode with increasing rotation speed rs can be shown. Furthermore, the automated contact mode shows better reproducibility behavior compared to manual contact modes.
Nanoscale Biocompatible Structures Generated from Fluorinated Tripodal Phenylenes on Gold Nanoprisms
Authors: García‐Castro Miguel , Moscoso Ana , Sarabia Francisco , López‐Romero Juan Manuel , Contreras‐Cáceres Rafael , Díaz Amelia
Published: March 2022

Modification of gold substrates with a stable, uniform and ultrathin layer of biocompatible materials is of tremendous interest for the development of bio‐devices. We present the fabrication of hybrid systems consisting of triangular prism gold nanoparticles (Au@NTPs) covalently covered with tripod‐shaped oligo(p‐phenylenes) featuring trifluoromethyl groups. Their synthesis is accomplished using a biphenyl boronic ester as the key compound. Au@NTPs were prepared through a seedless procedure using 3‐butenoic acid and benzyldimethyl ammonium chloride, and modified with aminothiol groups. Coverage of this amine‐modified gold substrate with a self‐assembled monolayer (SAM) of tripod‐shaped molecules is carried out in ethanolic solution. The hybrid system avoids up to 70 % of protein corona formation, and allows unspecific attachment for bulky adsorbates, providing an optimal biosensing platform. Chemical composition and morphology are analyzed by transmission electron microscopy (TEM), UV‐visible spectroscopy and field emission scanning electron microscopy (FESEM).
Simultaneous qualitative and quantitative analysis of 10 bioactive flavonoids in Aurantii Fructus Immaturus (Zhishi) by ultrahigh‐performance liquid chromatography and high‐resolution tandem mass spectrometry combined with chemometric methods
Authors: Wu Mengmei , Ma Shuting , Wu Menghua , Cao Hui , Zhang Ying , Ma Zhiguo
Published: March 2022

Introduction

Aurantii Fructus Immaturus (Zhishi in Chinese) is the dried young fruit of Citrus aurantium L. (CA) and its cultivated varieties or Citrus sinensis Osbeck (CS). The content of flavonoids in different varieties of Zhishi may be significantly different. However, there is confusion about the botanical origin of Zhishi, and there is no reliable and systematic method to control Zhishi quality.

Objectives

We aimed to establish an ultrahigh‐performance liquid chromatography method coupled with diode‐array detection and high‐resolution tandem mass spectrometry (UPLC‐DAD‐HRMS/MS) for the quantitative analysis of 10 flavonoids in Zhishi that could be used for quality control and botanical origin identification.

Methodology

A UPLC‐DAD‐HRMS/MS method was established for simultaneous identification and quantification of 10 flavonoids. Separation was performed on a Waters Acquity UPLC HSS T3 column (100 mm × 2.1 mm, 1.8 μm) with 0.1% formic acid and acetonitrile as mobile phase under gradient elution. MS was performed in positive and negative ionisation modes. The flavonoids in 41 batches were isolated and quantified. Zhishi of different botanical origins were identified by chemometrics.

Results

The results showed that the established method for the determination of 10 components was reliable and accurate. Chemometrics could be used to distinguish Zhishi of different botanical origins. There were significant differences in the contents of 10 flavonoids in samples of different botanical origins.

Conclusions

The quantitative analysis method in this study can be used to accurately determine the content of 10 flavonoids and provide a chemical basis for quality control and botanical origin identification of Zhishi.
Crystallization, microstructure and mechanical properties of directionally oriented films prepared using a novel blowing‐film process
Authors: Wu Sen‐lei , He Yue , Huang Wei‐dong , Qu Jin‐ping
Published: March 2022

A novel process of film preparation using a self‐made internal mandrel and external mold reverse rotation die is proposed. In this process, the mold's inner mandrel and outer parts rotate in opposite directions to achieve melt circumferential shear flow. In the blowing‐film process, a polymer melt is subjected to a flow field composed of extruded pressure extrusion and the reverse rotation of the die. The equipment has been used to successfully prepare low‐density polyethylene films. The microstructure and properties of films obtained under various internal and external reverse rotation speeds were studied. The results show that the rotation speeds are beneficial for forming a highly ordered crystalline structure of the film. As a result of microstructure evolution, the transverse direction (TD) tensile strength was enhanced by 39.4% and the machine direction (MD) tensile strength was enhanced by 47.4%. TD and MD breaking elongation increased by 38% and 43%, and the TD tensile breaking stress from 7.41 MPa was enhanced up to 10.79 MPa and the MD tensile breaking stress from 7.24 MPa was enhanced up to 11.26 MPa. The TD and MD tear strength increased by 38.2% and 28.3%. This novel blowing‐film process can be used to control the microstructure of films by controlling process parameters to improve the mechanical properties of films. © 2022 Society of Industrial Chemistry.
Current and projected workforce of spinal cord injury medicine board‐certified physicians through 2040
Authors: Svircev Jelena N. , Raddatz Mikaela M. , Leung Audrey S. , Burns Stephen P.
Published: March 2022

Care delivered by physicians experienced and trained in spinal cord injury medicine (SCIM) offers benefit to individuals with spinal cord injury (SCI). The American Board of Physical Medicine and Rehabilitation (ABPMR) offers board certification (BC) to physicians who have met eligibility requirements. Enough individuals must earn and maintain BC in order to maintain a SCIM specialty‐trained workforce. This study used demographic data of physicians with SCIM BC obtained from the ABPMR, American Board of Internal Medicine, American Board of Medical Specialties, and National Resident Matching Program. Since the SCIM Examination was first offered, 723 physicians received initial certification, and 464 physicians held BC in 2020. Peak workforce size is estimated to have occurred in 2007, and SCIM fellowship trained‐BC physicians began to make up the majority of all current SCIM board‐certified physicians in 2019. Models for best fit were developed with known data. Projections suggest a continued decrease in total SCIM board‐certified physicians until 2034, then only a slight increase until steady state is reached with 376 SCIM board‐certified physicians. If the number of individuals receiving SCIM BC remains unchanged, there will be reductions in SCIM board‐certified physicians for another 15 years. Whether this supply meets demand is unknown.
Tailoring the D‐A‐D electron‐withdrawing core as hole transport materials towards boosting the transport performance of perovskite solar cells
Authors: Zang Zifu , Chen Zhijian , Wang Jiaoyang , Song Peng , Li Yuanzuo
Published: March 2022

Five donor‐acceptor‐donor (D‐A‐D) hole transport materials (HTMs) are investigated to reveal the effect of core units on the structure‐property relationship. Structurally, the five electron‐withdrawing cores are derivatives of diazosulfide, and the bis(N, N‐bis(4‐[methoxy]phenyl))aniline segment performed as the symmetrical end‐capping. The DFT and TD‐DFT coupled with the Marcus theory are used to look into electronic structures, ground and excited state properties, charge transport mobilities, and charge transfer analyses. It is found that the HTM‐PT shows little differences in planarity, ionization potential, and solubility compared with the original molecule. Additionally, the HTM‐PT exhibits lower frontier molecular orbital (FMOs), smaller bandgap, and red‐shift than HTM‐DP. More importantly, among the four designed HTMs, the HTM‐PT shows a larger hopping rate and mobility. As the charge transfer analyses, the HTM‐PT exhibits a larger intramolecular charger transfer amount and charge transfer distance than the prototypical one, which is conducive to a larger short‐circuit current. Through the evaluation from various aspects, it is reasonable to infer that PT‐core with excellent properties has potential advantages in regulating HTMs.
Diptoindonesin G antagonizes AR signaling and enhances the efficacy of antiandrogen therapy in prostate cancer
Authors: Mao Fengyi , Kong Yifan , Liu Jinghui , Rao Xiongjian , Li Chaohao , Donahue Kristine , Zhang Yanquan , Jones Katelyn , Zhang Qiongsi , Xu Wei , Liu Xiaoqi
Published: March 2022

Background

The androgen receptor (AR) signaling pathway has been well demonstrated to play a crucial role in the development, progression, and drug resistance of prostate cancer. Although the current anti‐androgen therapy could significantly benefit prostate cancer patients initially, the efficacy of the single drug usually lasts for a relatively short period, as drug resistance quickly emerges.

Methods

We have performed an unbiased bioinformatics analysis using the RNA‐seq results in 22Rv1 cells to identify the cell response toward Dip G treatment. The RNA‐seq results were validated by qRT‐PCR. Protein levels were detected by western blot or staining. Cell viability was measured by Aquabluer and colony formation assay.

Results

Here, we identified that Diptoindonesin G (Dip G), a natural extracted compound, could promote the proteasome degradation of AR and polo‐like kinase 1 (PLK1) through modulating the activation of CHIP E3 ligase. Administration of Dip G has shown a profound efficiency in the suppression of AR and PLK1, not only in androgen‐dependent LNCaP cells but also in castration‐resistant and enzalutamide‐resistant cells in a CHIP‐dependent manner. Through co‐targeting the AR signaling, Dip G robustly improved the efficacy of HSP90 inhibitors and enzalutamide in both human prostate cancer cells and in vivo xenograft mouse model.

Conclusions

Our results revealed that Dip G‐mediated AR degradation would be a promising and valuable therapeutic strategy in the clinic.
Phosphate addition enhances alkaline extraction of glyphosate from highly sorptive soils and aquatic sediments
Authors: Wimmer Benedikt , Neidhardt Harald , Schwientek Marc , Haderlein Stefan B , Huhn Carolin
Published: March 2022

BACKGROUND

Analytical constraints complicate environmental monitoring campaigns of the herbicide glyphosate and its major degradation product aminomethylphosphonic acid (AMPA): their strong sorption to soil minerals requires harsh extraction conditions. Coextracted matrix compounds impair downstream analysis and must be removed before analysis.

RESULTS

A new extraction method combined with subsequent capillary electrophoresis‐mass spectrometry for derivatization‐free analysis of glyphosate and AMPA in soil and sediment was developed and applied to a suite of environmental samples. It was compared to three extraction methods from literature. We show that no extraction medium reaches 100% recovery. The new phosphate‐supported alkaline extraction method revealed (1) high recoveries of 70–90% for soils and aquatic sediments, (2) limits of detections below 20 μg kg−1, and (3) a high robustness, because impairing matrix components (trivalent cations and humic acids) were precipitated prior to the analysis. Soil and sediment samples collected around Tübingen, Germany, revealed maximum glyphosate and AMPA residues of 80 and 2100 μg kg−1, respectively, with residues observed along a core of lake sediments. Glyphosate and/or AMPA were found in 40% of arable soils and 57% of aquatic sediment samples.

CONCLUSION

In this work, we discuss soil parameters that influence (de)sorption and thus extraction. From our results we conclude that residues of glyphosate in environmental samples are easily underestimated. With its possible high throughput, the method presented here can resolve current limitations in monitoring campaigns of glyphosate by addressing soil and aquatic sediment samples with critical sorption characteristics.
Nonfragile consensus of nonlinear multiagent systems with intrinsic delays via aperiodic memory sampled‐data control
Authors: Han Sheng , Zhong Qishui , Wang Yang , Shi Kaibo , Zhong Shouming
Published: March 2022

This paper focuses on the consensus issue of nonlinear multiagent systems (MASs) with intrinsic time‐varying delays via the nonfragile and aperiodic memory sampled‐data control scheme. An improved continuous Lyapunov–Krasovskii functional (LKF) with some two‐sided looped‐functional terms is introduced, in which several free‐weighting‐matrices are not necessarily positive definite. Furthermore, based on the property of Laplacian matrix, the consensus issue of original MASs can be investigated directly without transforming into error systems. Then, several sufficient criteria for the consensus of MASs are presented by means of the recently developed generalized integral inequality and the constructed LKF. Next, the required nonfragile controller gain is obtained by resorting to linear matrix inequalities and the maximal length of sampling period is derived as well. Finally, two illustrative examples are employed to exhibit the effectiveness and feasibility of the proposed consensus protocol.
Targeting river operations to the critical thermal window of fish incubation: Model and case study on Sacramento River winter‐run Chinook salmon
Authors: Anderson James J. , Beer William Nicholas , Israel Joshua A. , Greene Sheila
Published: March 2022

Allocating reservoir flows to meet societal and ecosystem needs under increasing water demands and climatic variability presents challenges to resource managers. Often, rivers have been regulated to meet flow and temperature compliance points or mimic historical patterns. Because it is difficult to assess if this approach is efficient, process‐based models are being used to design river operations. This paper describes a model for fish incubation survival based on the premise that mortality from thermal stress occurs over a critical window (CW) of embryo development. A model for the embryo CW based on metabolic studies of development is combined with density‐dependent and background mortalities to describe salmonid survival from egg fertilization to fry detection downstream. The model is calibrated with a two‐decade dataset of Sacramento River winter‐run Chinook salmon egg‐to‐fry survival. The effects of temperature exposure over a range of CWs were explored. Based on statistical and biological support, two alternative CWs were identified for temperature control: the entire incubation period and a short duration window prior to hatching. Survival under different CW assumptions and temperature control operations were simulated with an internet‐accessible form of the model. The analysis indicated that under years of limited cold‐water resources, targeting water releases to the CW prior to hatching would yield the highest incubation survival.
NiO‐MnOx/Polyaniline/Graphite Electrodes for Urea Electrocatalysis: Synergetic Effect between Polymorphs of MnOx and NiO.
Authors: Hefnawy Mahmoud A. , Medany Shymaa S. , El‐Sherif Rabab M. , Fadlallah Sahar A.
Published: March 2022

In this work, we are enhancing the catalytic activity of the urea electrooxidation (UEO) process by using the composite of polyaniline (Pani), nickel oxide (NiO), and polymorphs of manganese oxide (MnOx) based on a graphite electrode. The hydro‐gel method was used to prepare catalyst suspension with different ratios from NiO and MnOx. The chemical structures and surface morphology were characterized by employing the IR, XRD, and SEM/EDEX techniques. The catalytic activity of four modified electrocatalysts G/Pani/NiMn1, G/Pani/NiMn2, G/Pani/NiMn3, G/Pani/NiMn4 was investigated using cyclic voltammetry, chronoamperometry, and electrochemical impedance. The kinetic parameters such as diffusion coefficient, Tafel slope, charge transfer coefficient, and surface coverage were calculated to choose the best electrocatalysts toward UEO in alkaline solution. The anodic current of new electrodes achieved about 16 mA.cm−2at potential of 550 mV (vs. Ag/AgCl). Density functional theory studies (DFT) have been carried out to assess the adsorption energy between polyaniline (Pani) and the metal oxides.
Lignin@Ni‐NPs: A Novel, Highly Efficient, Recyclable, and Selective Nanocatalyst for Base‐Free Transfer Hydrogenation Reactions at Room Temperature
Authors: Bharamanagowda Marulasiddeshwara Madrahalli , Panchangam Raghavendra Kumar
Published: March 2022

Nickel nanoparticles were synthesized readily by sonication of a mixture of nickel(II) chloride hexahydrate, hydrazine hydrate, lignin and water at 60 °C. This lignin supported nickel nanoparticles (Lignin@Ni‐NPs) have been characterized by UV‐Visible, PXRD, EDX, SEM and TEM techniques. The average size of Ni‐NPs was found in the range of 15‐20 nm as revealed by TEM micrographs. The amount of nickel(0) loaded in Lignin@Ni‐NPs determined by EDX was 36.6 %. The catalytic activity of Lignin@Ni‐NPs have been evaluated in the transfer hydrogenation of carbonyl compounds into the corresponding alcohols. The catalyst have been found efficient for hydrogen‐transfer reduction of functionalised and non‐fuctionalised including heteroaromatic carbonyl compounds as the desired alcohols were obtained in high yields of about 90‐95 % at room temperature, under base‐free conditions and in short reaction times. The catalyst was recovered by simple filtration and it has an advantage of being reuable more than six times without significant loss in its catalytic activity.
Research Progress in the Pharmacological Effects and Synthesis of Nicotine
Authors: Ye Xiaoping , Zhang Yanxin , Song Xiaoping , Liu Qingchao
Published: March 2022

Nicotine is an alkaloid found in solanaceae plants and an important component in tobacco. It is the main substance that causes smoking addiction and can have many effects on the nervous system. In recent years, nicotine has been found to have the value of drug transformation research, which has attracted the attention of a large number of scholars in the fields of organic synthesis and medicinal chemistry. Related drug transformation research and chemical synthesis continue to emerge. This article mainly summarizes the research progress of nicotine pharmacological effects and synthesis.
Simultaneous Detection of Pb2+ and Cu2+ on β‐CD‐NH2‐Fe3O4 Modified Electrode
Authors: Huang Baomei , Luo Xi , Pu Qingmiao , Guo Junchun , Tong Xinyu , Lu Xiaoquan
Published: March 2022

β‐CD‐NH2‐Fe3O4 magnetic nanomaterials were prepared and the electrochemical sensor was constructed using β‐CD‐NH2‐Fe3O4 magnetic nanomaterials modified GCE to determine toxic heavy metals(Pb2+, Cu2+) in river water. SEM, XRD and FTIR were used to characterize the structure and phase of β‐CD‐NH2‐Fe3O4. DPV results indicated that β‐CD‐NH2‐Fe3O4 modified GCE possessed large active area and excellent electron transfer. Under the optimum conditions, the peak current was proportional to the ion concentration in the range of 40 nM∼10 μM. LOD of Pb2+ and Cu2+ in this method was 1.71 nM and 1.57 nM, respectively. Compared with other similar results reported in the literature, the β‐CD‐NH2‐Fe3O4 modified electrode exhibited wider linear response range while with comparable lower LOD. It also exhibited excellent stability, reproducibility and anti‐interference ability.
CBr4 Promoted α‐Acyloxyation of β‐Keto Esters and β‐Diketones by Sodium Carboxylates
Authors: Zhou Xiaoqiang , Ma Haojie , Zhou Nengneng , Cai Xiuqin
Published: March 2022

CBr4 promoted C−O coupling of β‐keto esters and β‐diketones with sodium carboxylates has been developed. This mild and operationally simple methodology, using sodium carboxylates as acyloxyation source and deacid reagent, provides an efficient pathway for the acquisition of prospective α‐acyloxylated ketones.
Self‐Supported CuO In‐Situ‐Grown on Copper Foil as Binder‐Free Anode for Lithium‐Ion Batteries
Authors: Liu Yang , Liu Han , Cai Xuesong , Li Xingqiu , Chen Yuan , Ye Nini , Liang Chenglu
Published: March 2022

Transition metal oxides as anode materials for lithium‐ion batteries (LIBs) possess the advantages of high specific capacity and abundance. However, most reported transition metal oxides based active anode materials were coated on the copper current collector with the addition of inactive polymer binder and conductive agents, resulting in low utilization of active substances. To solve this problem, nanostructured CuO with different morphologies (CuO bunches, CuO nanosheets, CuO nanotubes) were in‐situ grown on the copper current collectors via a simple wet chemical oxidation method. The as‐obtained CuO@Cu foils were used directly as anode for LIBs. CuO nanotubes exhibited excellent electrochemical performance and sustained a reversible discharge specific capacity of 798 mA h g−1 after 60 cycles at 100 mA g−1. At current density of 1000 mA g−1, a high specific capacity of 758 mA h g−1 can be obtained after 200 cycles. The satisfying electrochemical performances of the CuO nanotubes anode indicated that a stable composite structure of CuO@Cu foils was achieved in the binder free electrode. This work demonstrated the feasibility of this binder free strategy in the development of electrode materials for high performance lithium‐ion batteries design.
Synthesis of Dual Red‐Emitting Fluorescent Silver Nanoclusters in Aqueous Lipoic Acid‐Based Polymer Solutions and Application for Cu2+ Detection and Cell Imaging
Authors: Yang Tao , Xie Yangchun , Zhang Sanjun , He Xiaohua
Published: March 2022

Dual red‐emitting fluorescent and water‐soluble silver nanoclusters (AgNCs) were synthesized in aqueous solutions through the reduce reaction method using lipoic acid‐modified‐poly(vinyl alcohol) as a novel protective ligand and sodium borohydride as a reducing agent. The obtained AgNCs exhibited a large Stokes shift and high stability. The fluorescence lifetime of the obtained AgNCs was 1.4×104 ns and the corresponding quantum yield reached 7.1 %. The obtained AgNCs showed highly sensitive and selective detection of Cu2+, in which the evaluation of Cu2+ was allowed in the range of 0–28 μM with a limit of detection (LOD) as low as 0.71 μM. Moreover, the obtained AgNCs are explored to application for bioimaging through incubation with ID8 cells.
Synthesis and Characterization of New Nanocomposites Based on Montmorillonite and Hexahydroquinolinyl Ether Hybrids
Authors: Abd Allah Omyma A. , Elshater Abdelhamid
Published: March 2022

Familiarly, montmorillonite (MMT) ‐ based composites are prepared by the absorption method, which produced unstable MMT composites, since the adsorbates were easily pull out from MMT. Herein, using a new technique, the hexahydro‐ quinolinylhexahydroquinolinyl ethers resulting from the cyclization reaction of 1,3‐cyclohexanedione with p‐aminophenol and arylidinemalono‐ nitrilesarylidinemalononitriles in presence of Ca‐montmorillonite (Ca‐MMT), were grafted on Ca‐MMT surface via formation of coordinate bonds to produce stable nanocomposites. In these reactions, Ca‐MMT played as a heterogeneous catalyst and as the hydrophobic surface chemically bonded with the formed ether molecules. NMR, FTIR and XRD analyses confirmed the successful surface modification of the nanoparticles clay with the formed ethers molecules via formation of coordinate and hydrogen bonds. These stable nanocomposites are characterized by their thermal stability and higher solubility in dioxane and dimethyl sulphoxide solvents.Also, these nanocomposites has a potential application in environment, biomedicine and engineered barriers.
Geometric Engineering of Porous PtCu Nanotubes with Ultrahigh Methanol Oxidation and Oxygen Reduction Capability
Authors: Xu Feng , Cai Shaobin , Lin Benfeng , Yang Liu , Le Huafeng , Mu Shichun
Published: March 2022

Platinum (Pt), as a commonly used electrocatalyst in direct methanol fuel cells (DMFCs), suffers from sluggish kinetics of both the methanol oxidation reaction (MOR) and oxygen reduction reaction (ORR). Geometric engineering has been proven effective for improving the MOR and ORR activities. Thus, by modulating the Pt precursor and poly(vinylpyrrolidone) (PVP) dosages, different porous PtCu nanotubes constructed by hollow nanospheres, solid alloy, and Pt‐rich skinned nanoparticles, respectively, are successfully synthesized. Among them, the solid PtCu alloy nanoparticle coherent nanotubes exhibit the specific activity 9.42 times higher than Pt/C toward MOR, while the hollow PtCu alloy nanosphere coherent nanotubes show the specific activity 4.85 times higher than Pt/C toward ORR. The different Pt:Cu ratios of hollow nanospheres, solid alloy, and Pt‐rich skinned nanoparticles cause the differences in electron transfer from Cu to Pt as well as electronic structures of Pt. As a result, the binding energies of intermediates can be regulated, leading to the enhancement in MOR and ORR.
Large‐Area Covalent Organic Polymers Membrane via Sol–Gel Approach for Harvesting the Salinity Gradient Energy
Authors: Zhang Caili , Xiao Tianliang , Lu Bingxin , He Jianwei , Wang Yuting , Zhai Jin
Published: March 2022

Many materials with nanofluidic channels are exploited to achieve salinity gradient energy conversion. However, most materials are fragile, difficult to process, or only prepared into a limited size, which greatly restricts their practical application in the future. Herein, a covalent organic polymers membrane with high mechanical property and stability is fabricated, which can keep integrity in harsh conditions for up to 1 month. In addition, by using the sol–gel approach, a large‐area membrane with an area of 26 × 26 cm is expediently fabricated in lab conditions. When the membrane is applied to salinity gradient energy conversion, the maximum output power density is up to 6.21 W m−2. This work provides a simple method for the fabrication of large‐area membrane for salinity gradient energy conversion in future real‐world applications.
The Road to Achieving the European Commission's Chemicals Strategy for Nanomaterial Sustainability—A PATROLS Perspective on New Approach Methodologies
Authors: Doak Shareen H. , Clift Martin J. D. , Costa Anna , Delmaar Christiaan , Gosens Ilse , Halappanavar Sabina , Kelly Sean , Pejinenburg Willie J. G. M. , Rothen‐Rutishauser Barbara , Schins Roel P. F. , Stone Vicki , Tran Lang , Vijver Martina G. , Vogel Ulla , Wohlleben Wendel , Cassee Flemming R.
Published: March 2022

The European Green Deal outlines ambitions to build a more sustainable, climate neutral, and circular economy by 2050. To achieve this, the European Commission has published the Chemicals Strategy for Sustainability: Towards a Toxic‐Free Environment, which provides targets for innovation to better protect human and environmental health, including challenges posed by hazardous chemicals and animal testing. The European project PATROLS (Physiologically Anchored Tools for Realistic nanOmateriaL hazard aSsessment) has addressed multiple aspects of the Chemicals Strategy for Sustainability by establishing a battery of new approach methodologies, including physiologically anchored human and environmental hazard assessment tools to evaluate the safety of engineered nanomaterials. PATROLS has delivered and improved innovative tools to support regulatory decision‐making processes. These tools also support the need for reducing regulated vertebrate animal testing; when used at an early stage of the innovation pipeline, the PATROLS tools facilitate the safe and sustainable development of new nano‐enabled products before they reach the market.
Boosting Oxygen Reduction for High‐Efficiency H2O2 Electrosynthesis on Oxygen‐Coordinated CoNC Catalysts
Authors: Shen Hangjia , Qiu Nianxiang , Yang Liu , Guo Xuyun , Zhang Kun , Thomas Tiju , Du Shiyu , Zheng Qifu , Attfield J. Paul , Zhu Ye , Yang Minghui
Published: March 2022

Atomically dispersed CoNC is a promising material for H2O2 selective electrosynthesis via a two‐electron oxygen reduction reaction. However, the performance of typical CoNC materials with routine CoN4 active center is insufficient and needs to be improved further. This can be done by fine‐tuning its atomic coordination configuration. Here, a single‐atom electrocatalyst (Co/NC) is reported that comprises a specifically penta‐coordinated CoNC configuration (OCoN2C2) with Co center coordinated by two nitrogen atoms, two carbon atoms, and one oxygen atom. Using a combination of theoretical predictions and experiments, it is confirmed that the unique atomic structure slightly increases the charge state of the cobalt center. This optimizes the adsorption energy towards *OOH intermediate, and therefore favors the two‐electron ORR relevant for H2O2 electrosynthesis. In neutral solution, the as‐synthesized Co/NC exhibits a selectivity of over 90% over a potential ranging from 0.36 to 0.8 V, with a turnover frequency value of 11.48 s−1; thus outperforming the state‐of‐the‐art carbon‐based catalysts.
Single atom and defect engineering of CuO for efficient electrochemical reduction of CO2 to C2H4
Authors: Chu Senlin , Kang Changwoo , Park Woonghyeon , Han Yu , Hong Song , Hao Leiduan , Zhang Hao , Lo Tsz Woon Benedict , Robertson Alex W. , Jung Yousung , Han Buxing , Sun Zhenyu
Published: March 2022

Electrochemical CO2 transformation to high‐value ethylene (C2H4) at high currents and efficiencies is desired and yet remains a grand challenge. We show for the first time that coupling single Sb atoms and oxygen vacancies of CuO enable synergistic electrocatalytic reduction of CO2 to C2H4 at low overpotentials. Highly dispersed Sb atoms occupying metal substitutional sites of CuO are synthesized under mild conditions. The overall CO2 reduction faradaic efficiency (FE) reaches 89.3 ± 1.1% with an FE toward C2H4 exceeding 58.4% at a high‐current density of 500 mA/cm2. Addition of the p‐block metal is found to induce transformation of CuO from flakes to nanoribbons rich in nanoholes and oxygen vacancies, greatly enhancing CO2 adsorption and activation while suppressing hydrogen evolution. Further density functional theory calculations with in situ X‐ray diffraction reveal that combining Sb sites and oxygen vacancies prominently lessen the dimerization energy of adsorbed CO intermediate, thus boosting the conversion of CO2 to produce C2H4. This study provides a new perspective for promoting selective C–C coupling for electrochemical CO2 reduction.
Early Jurassic coprolites: insights into palaeobotany and the feeding behaviour of dinosaurs
Authors: Barbacka Maria , Górecki Artur , Pacyna Grzegorz , Pieńkowski Grzegorz , Philippe Marc , Bóka Károly , Ziaja Jadwiga , Jarzynka Agata , Qvarnström Martin , Niedźwiedzki Grzegorz
Published: March 2022

Analyses of coprolites provide important data on animal feeding and food quality, including information on the taxonomy of the biotope. Knowledge of the diet of extinct animals has implications for our understanding of the evolution of various physiological strategies and feeding adaptations. Here we provide the first description of plant remains preserved in coprolites from early Hettangian deposits at Sołtyków (Holy Cross Mountains, Poland). The coprolites probably originated from herbivorous sauropodomorphs, ornithischians and large carnivorous theropods, from which tracks are known from the site. Herbivorous coprolite producers fed on the flora growing on a fluvial plain, and the cuticles that remain in the coprolites originated from crowns of gymnospermous trees or shrubs. Coprolites assigned to large predators contained more diverse plant remains, although they also belonged to the gymnosperms. These were probably ingested together with the stomachs and intestines of prey animals and/or accidentally while drinking or feeding. The plant cuticles originated from seed ferns (including the newly proposedKomlopteris distinctivaBarbacka sp. nov.), cycadophytes, ginkgophytes and conifers. A fragment of a needle leaf,Aciphyllum triangulatumBarbacka & Górecki gen. et sp. nov., is very similar to the leaves ofPinus, and is the oldest example of such a leaf type in the fossil record. Most ingested plants came from beyond the immediate surroundings of today’s outcrop. Palynological analysis of the coprolites yielded 31 taxa of sporomorphs from the herbivore coprolites and 14 sporomorph taxa from the coprolites of predators. Cheirolepidiaceous pollen grains ofClassopollis torosusdominated the sporomorph assemblage.
Ressourcen‐ und Emissionseffizienz im Brückenbau am Beispiel der Campusbrücke Leverkusen
Authors: Halaczek Bartlomiej , Nowak Jana , Helbig Thorsten , Riederer Jochen , van Acken Ulrich , Neubauer Hendrik
Published: March 2022

Das Bauwesen ist weltweit einer der größten Verursacher von klimaschädlichen CO2‐Emissionen. Lösungen für den Weg hin zum klimaneutralen Bauen und Betreiben sind nur durch eine ganzheitliche Auseinandersetzung zu finden, die auch den Umgang mit Ressourcen mit einschließt. Dies umfasst Fragen von Notwendigkeit und Ausmaß eines Bauwerks (build less) über eine geplante Wiederverwendung von Bauteilkomponenten und angestrebte Materialreduzierung im Entwurfsprozess (build clever) bis hin zur Auswahl der Materialien basierend auf der Berücksichtigung der baustoffspezifischen grauen Emissionen (build efficiently) in einem möglichst geschlossenen Material‐Kreislaufsystem (minimise waste). Eine einheitliche Bewertung der Ressourcen‐ und Emissionseffizienz von Brückenbauwerken ist aufgrund des Fehlens international abgestimmter Regelungen derzeit noch nicht abbildbar. Am Beispiel der Campusbrücke in Leverkusen‐Opladen, einer 2013 erbauten Fußgängerbrücke, werden verschiedene praktische Ansätze vorgestellt, die zu einer Emissionsreduktion und Ressourcenschonung beigetragen haben. Anhand einer Lebenszyklusanalyse (LCA) wird das gewählte Tragwerk einer alternativen Ausführung gegenübergestellt.
Research on the bending damage of concrete in areas with large temperature differences based on 3D‐Digital Image Correlation
Authors: Shi Jinna , Zhao Yanru , Bai Jianwen , He Xiaoyan
Published: March 2022

Digital Image Correlation (DIC) technique is used to collect the whole‐field strain of concrete subjected to bending loads under different temperature change cycles, cooling rates, and water‐binder ratio. The bending damage behavior of concrete under large‐difference temperature circulation is analyzed with the whole‐field strain cloud map and data. In addition, with the whole‐field strain obtained by 3D‐DIC technology, the strain‐based damage variable is defined. Furthermore, the damage degree of concrete specimen in the bending process is quantified, and the bending damage evolution process of concrete under the action of temperature circulation is discussed. The results show that the damage of concrete in areas with large temperature differences is related to the number of temperature change cycles as well as the cooling rate. Moreover, the increase in the number of temperature change cycles and the cooling rate will aggravate the bending damage of the concrete. Additionally, the higher the water‐binder ratio, the more serious the adverse effect of temperature circulation on the concrete. This paper provide certain reference for the evaluation of concrete bending deformation damage in areas with a large temperature difference.
Free and open source software for computational chemistry education
Authors: Lehtola Susi , Karttunen Antti J.
Published: March 2022

After decades of waiting, computational chemistry for the masses is finally here. Our brief review on free and open source software (FOSS) packages points out the existence of software offering a wide range of functionality, all the way from approximate semiempirical calculations with tight‐binding density functional theory to sophisticated ab initio wave function methods such as coupled‐cluster theory, covering both molecular and solid‐state systems. Combined with the remarkable increase in the computing power of personal devices, which now rivals that of the fastest supercomputers in the world in the 1990s, we demonstrate that a decentralized model for teaching computational chemistry is now possible thanks to FOSS packages, enabling students to perform reasonable modeling on their own computing devices in the bring your own device (BYOD) scheme. FOSS software can be made trivially simple to install and keep up to date, eliminating the need for departmental support, and also enables comprehensive teaching strategies, as various algorithms' actual implementations can be used in teaching. We exemplify what kinds of calculations are feasible with four FOSS electronic structure programs, assuming only extremely modest computational resources, to illustrate how FOSS packages enable decentralized approaches to computational chemistry education within the BYOD scheme. FOSS also has further benefits driving its adoption: the open access to the source code of FOSS packages democratizes the science of computational chemistry, and FOSS packages can be used without limitation also beyond education, in academic and industrial applications, for example.

This article is categorized under:

Software > Quantum Chemistry
Bimetallic Organoplatinum(II)‐Ag(I) Cluster Cations with Ag−Pt Interactions Unsupported by Conventional Bridging Ligands
Authors: Raven William , Kalf Irmgard , Paulmann Carsten , Englert Ulli
Published: March 2022

The organoplatinum complex of a primary amine and AgClO4 aggregate in methanol to oligonuclear mixed‐metal species. A perchlorate salt 3 with the empirical formula C96H146Ag7Cl13N12O62Pt6 could be isolated and structurally characterized with the help of X‐ray diffraction at the DESY synchrotron. The product contains both a penta‐ and a tetra‐nuclear complex cation in which Ag(I) and Pt(II) alternate, held together without any conventional bridge. The cationic species feature short Ag⋅⋅⋅Pt distances between 2.7 and 2.9 Å and contacts longer than 2.4 Å between Ag and C atoms in aromatic rings. In addition to the interactions with Ag(I) cations, Pt(II) is in a square‐planar arrangement, coordinated by a chelating and a terminal amine and an aqua ligand. The central Ag(I) in the pentanuclear cation is located on a twofold crystallographic axis and not involved in any obvious coordinative bond; it exclusively shows short contacts to the neighboring Pt(II) ions and the Pt‐bonded, formally anionic carbon atoms of the cyclometallated organic ligand. Powder diffraction shows that 3 melts and re‐solidifies without decomposition.