bluuebunny/crossref_metadata_2025 huggingface dataset:
Photocatalytic degradation of basic blue dye using zinc nanoparticles decorated graphene oxide nanosheet
Authors: Al Aqad Khaled M. , Basheer Chanbasha
Published: August 2020

Reduced graphene oxide nanosheets were prepared by a modified hummer method and decorated with zinc nanoparticles to form nanocomposite (ZnO/RGO). The nanostructure surface materials of RGO with ZnO consist of different functional groups such as carboxyl, carbonyl, and hydroxyl groups, which facilitate the oxidation process of dye. Various techniques characterized the synthesized nanocomposites. Scanning electron microscopy (SEM) showed good surface morphology of ZnO/RGO, and X‐ray diffraction illustrated a high crystal structure of the surface. Fourier‐transform infrared spectroscopy (FTIR) shows the functional groups of nanocomposites ZnO/RGO. The Raman and X‐ray photoelectron spectroscopy (XPS) spectroscopies illustrate the surface and functional properties of ZnO/RGO catalyst. Moreover, the optical characterization achieved good value around 3.29 eV because of the decoration of ZnO on the surface of graphene oxide. Optimized conditions show up to 98% photocatalytic degradation of basic blue dye. Liquid chromatography–mass spectrometry was used for the analysis of degradation and intermediate identification. The proposed degradation mechanism of basic blue by the following steps, cleavage of C–C bonds in the benzene ring, and N‐N bond during the attack of OH• radicals, (iii) cleavage of aniline and C–C bonds of the benzene group.
A prevalence and psychometric study on fear of cancer in women with abnormal cervical cytology undergoing colposcopy
Authors: Uner Fatma Ozlem , Korukcu Oznur
Published: August 2020

Objective

To determine the levels of fear of cancer in women who were referred for colposcopy and to determine validity and reliability of the Cancer Worry Scale (CWS) in gynaecology patients.

Methods

The study was conducted between March‐November 2017 with 200 women at the Gynaecologic Oncology Clinic at Akdeniz University Hospital in Turkey. Reliability analysis, confirmatory factor analyzes, and multidimensional sum‐score estimation were used for psychometric analyzes. One‐way ANOVA and independent samplest‐test were also used.

Results

Total score for the CWS of the participants was determined as 20.05 ± 7.87 in colposcopy patients. Marital status, information about the Papanicolaou (Pap) smear test and colposcopy, and fear of colposcopy were strongly associated with fear of cancer. We determined that a one‐factor structure emerged for the scale and that the total contribution of this factor to the explained variance was 53.35%. CFA was applied to obtain additional evidence of structural validity in line with the scores obtained from the scale. The overall Cronbach's alpha coefficient of the scale was 0.87.

Conclusions

Our study revealed that levels of fear of cancer were high in women who were referred for colposcopy. Furthermore, the CWS was determined as a valid and reliable tool to measure the fear of cancer in women undergoing cervical screening/follow‐up for abnormal cytology.
Pediatric Psychosocial Standards of Care in action: Research that bridges the gap from need to implementation
Authors: Wiener Lori , Canter Kimberly , Long Kristin , Psihogios Alexandra M. , Thompson Amanda L.
Published: August 2020

Objective

To describe innovative models of psychosocial care delivery that align with published Standards of Psychosocial Care of Children with Cancer and their Families, in efforts to bridge the divide between research and practice.

Methods

The Mattie Miracle Cancer Foundation, in partnership with the American Psychosocial Oncology Society reviewed 22 letters of intent and 13 full grants and awarded small grants to researchers with high quality projects that aimed to implement any of the published 15 Standards of Care. For three of the highest rated funded research projects, we describe the Standard implemented, the novel research design and implementation strategies, and how the research findings might inform the development, implementation, and dissemination of effective solutions for bridging Standard‐to‐practice gaps.

Results

The first study presented is an innovative eHealth intervention for parents of children with cancer designed to improve family functioning and decrease symptoms of acute distress, anxiety, and posttraumatic stress. The second study addresses the acceptability and feasibility of using daily text message assessments of oral chemotherapy adherence in adolescents and young adults with leukemia, and the third creates a blueprint for providing psychosocial services to siblings, including ways to overcome common implementation barriers.

Conclusions

Several themes emerged from the studies presented, including (1) attention to barriers to previous attempts at implementation; (2) technology's role in delivering care; (3) the need for stakeholder involvement; and (4) consideration for multi‐pronged solutions that address heterogeneity in care settings. Next steps for integrating the Standards of Psychosocial Care into clinical practice are discussed.
Aurantio‐obtusin improves obesity and insulin resistance induced by high‐fat diet in obese mice
Authors: Guo Cong‐Ying , Liao Wei‐Tao , Qiu Rui‐Jin , Zhou Dan‐Shui , Ni Wei‐Ju , Yu Cui‐Ping , Zeng Yu
Published: August 2020

Aurantio‐obtusin (AUR) is the main bioactive compound among the anthraquinones, from Cassia seed extract. This study was conducted to identify whether AUR could improve obesity and insulin resistance, induced by a high‐fat diet in obese mice. Mice were fed a high‐fat diet for 6 weeks and were then assigned to the high‐fat diet (HFD) control group, the AUR 5 mg/kg group, or the AUR 10 mg/kg group. AUR improves glucose by activating the expression of PI3K, Akt and GLUT4, GLUT2. AUR altered the expression levels of several lipid metabolism‐related and adipokine genes. AUR decreased the mRNA expression of PPAR‐γ, FAS and increased the mRNA expression of PPAR‐α in liver. AUR lowered SREBP‐1c, FAS, SCD‐1, inflammatory cytokines, and increased the expression of PPAR‐γ, PPAR‐α, CPT‐1, and adiponectin in white adipose tissue (WAT). AUR docking with the insulin receptor showed that the residues of the insulin receptor, ectodomain, were the same as those around the emodin. The effect of AUR may be elicited by regulating the activity of the insulin signaling pathway, expression of lipid metabolism‐related genes, and expression of inflammatory cytokine markers to improve adiposity, insulin resistance, and dyslipidemia.
Effect of recycled content and rPET quality on the properties of PET bottles, part III: Modelling of repetitive recycling
Authors: Brouwer Marieke T. , Alvarado Chacon Fresia , Thoden van Velzen Eggo Ulphard
Published: August 2020

The presence of contaminants in polyethylene terephthalate (PET) bottles and derived materials from the various steps in the recycling loop is studied. Based on these measurements, a model is proposed to generically describe the accumulation of these contaminants within closed‐loop recycling schemes for PET bottles. The measured levels of particle contamination and chlorine content of PET bottles, pellets, and intermediate recycling products are used to derive the modelling parameters. Previously determined relations between these measured parameters and critical bottle properties are used to model the effect of the accumulation of the contaminants on the bottle properties. The measurements reveal that the type of collection system influences the accumulation of contaminants in PET bottles greatly. PET bottles in mono‐collection systems accumulate less contaminants than PET bottles in co‐collection systems do. Therefore, PET bottles within recycling schemes using mono‐collection systems can contain more recycled content than those from co‐collection systems, without exceeding acceptation limits on critical bottle properties such as haziness, yellowing, and migration.
Topology delimited radical‐scavenging propensity of monohydroxycinnamic acids
Authors: Borislavov Lyuben , Velkov Zhivko , Tadjer Alia
Published: August 2020

Hydroxyl derivatives of cinnamic acid, both natural and synthetic, are well‐known radical scavengers. However, not all of them feature the same radical‐scavenging propensity. Establishing the relationship between the structure of those species and their reactivity toward radicals plays a crucial role in the design of novel antioxidant pharmaceuticals founded on the same parent structure. This study aims to clarify, in a systematic and comprehensive way, the relationship between topology, geometry, and electron and spin density distribution on the one hand and the radical‐scavenging activity on the other. Different mechanisms are discussed based on the enthalpies of the possible structures generated in the process of dissociation of the OH bonds. All structures are modeled utilizing the first principles methods and accounting for the polar medium (water) at neutral pH (B3LYP/6‐311++G**/PCM). A hybrid mechanism is suggested, applicable not only to hydroxylated cinnamic acids but to phenolic acids in a polar environment in general.
pysisyphus: Exploring potential energy surfaces in ground and excited states
Authors: Steinmetzer Johannes , Kupfer Stephan , Gräfe Stefanie
Published: August 2020

Predicting the energetics of chemical transformations requires localizing stationary points on a potential energy surface. While educts and products of a chemical reaction may be known, transition state optimization is challenging as good guesses may be unavailable. Extending stationary point searches to the excited state leads to additional difficulties as several states may be close in energy, requiring efficient state tracking. Here, we report the implementation of pysisyphus, an external optimizer, that allows localization of stationary points not only in the ground state but also for excited state by providing several state‐tracking algorithms. pysisyphus offers all necessary tools for calculating reaction paths, starting from the optimization of the reactants, running chain‐of‐states methods such as the nudged elastic band or the growing string method with subsequent transition state optimization, and a concluding intrinsic reaction coordinate calculation.
A segmented measurement error model for modeling and analysis of method comparison data
Authors: Kotinkaduwa Lak N. , Choudhary Pankaj K.
Published: August 2020

Method comparison studies are concerned with estimating relationship between two clinical measurement methods. The methods often exhibit a structural change in the relationship over the measurement range. Ignoring this change would lead to an inaccurate estimate of the relationship. Motivated by a study of two digoxin assays where such a change occurs, this article develops a statistical methodology for appropriately analyzing such studies. Specifically, it proposes a segmented extension of the classical measurement error model to allow a piecewise linear relationship between the methods. The changepoint at which the transition takes place is treated as an unknown parameter in the model. An expectation‐maximization‐type algorithm is developed to fit the model and appropriate extensions of the existing measures are proposed for segment‐specific evaluation of similarity and agreement. Bootstrapping and large‐sample theory of maximum likelihood estimators are employed to perform the relevant inferences. The proposed methodology is evaluated by simulation and is illustrated by analyzing the digoxin data.
Measurement error and precision medicine: Error‐prone tailoring covariates in dynamic treatment regimes
Authors: Spicker Dylan , Wallace Michael P.
Published: August 2020

Precision medicine incorporates patient‐level covariates to tailor treatment decisions, seeking to improve outcomes. In longitudinal studies with time‐varying covariates and sequential treatment decisions, precision medicine can be formalized with dynamic treatment regimes (DTRs): sequences of covariate‐dependent treatment rules. To date, the precision medicine literature has not addressed a ubiquitous concern in health research—measurement error—where observed data deviate from the truth. We discuss the consequences of ignoring measurement error in the context of DTRs, focusing on challenges unique to precision medicine. We show—through simulation and theoretical results—that relatively simple measurement error correction techniques can lead to substantial improvements over uncorrected analyses, and apply these findings to the sequenced treatment alternatives to relieve depression study.
Multiple imputation score tests and an application to Cochran‐Mantel‐Haenszel statistics
Authors: Lu Kaifeng
Published: August 2020

The standard multiple imputation technique focuses on parameter estimation. In this study, we describe a method for conducting score tests following multiple imputation. As an important application, we use the Cochran‐Mantel‐Haenszel (CMH) test as a score test and compare the proposed multiple imputation method with a method based on the Wilson‐Hilferty transformation of the CMH statistic. We show that the proposed multiple imputation method preserves the nominal significance level for three types of alternative hypotheses, whereas that based on the Wilson‐Hilferty transformation inflates type I error for the “row means differ” and “general association” alternative hypotheses. Moreover, we find that this type I error inflation worsens as the amount of missing data increases.
Ultrathin Silica‐Coated Iron Oxide Nanoparticles: Size‐Property Correlation
Authors: Gupta Pranshu K. , Dravid Vinayak P. , De Mrinmoy
Published: August 2020

Magnetic nanostructures (MNS) in their superparamagnetic form are promising materials systems for contrast enhancement in magnetic resonance imaging (MRI) and thermal‐activation therapeutics via RF heating. These biomedical applications and associated properties are very much dependent on the structure, composition and size/shape of MNS. Although there are many speculations on the effect of various parameters on MNS, the size dependent properties are not well understood, largely due to challenges in size‐selective large‐scale synthesis for precise measurements and interference from typical large surface coating. Herein we report the size effect of iron oxide MNS on hydrodynamic radius, zeta potential, magnetic property and relaxivity. For this study, we have synthesized a wide range of monodispersed iron oxide MNS, from 7 nm to 20 nm nominal size and phase transferred to aqueous media with very thin layer of silica coating using Polyhedral Oligomeric Selesquioxanes (POSS). The dynamic light scattering (DLS) study and zeta potential measurement were carried out to determine the hydrodynamic radius and surface charges. The hydrodynamic radius follow the linear correlation but the zeta potential does not maintain it due to nonlinear mass/charge ratio relations with varying size. We have also conducted correlative studies of magnetic saturation (Ms) and
relaxivities. This work will highlight the size dependent correlation and tailoring of MNS properties for desired biomedical applications.
One‐Step Synthesis of Solid‐State Photoluminescent Carbon Nanodots from Grains for Latent Fingerprint Detection
Authors: Wang Yaping , Ju Wei , Chen Jianjun , Liu Ziying , Wang Jianshe
Published: August 2020

Employing grains (wheat, corn, sorghum and rice) as precursors, a series of carbon nanodots (CDs) have been prepared via one‐step hydrothermal treatment. All the CDs have narrow size distribution, roughly spherical shape and similar optical properties. The size depends on the precursors, which varies from 2 to 25 nm. The CDs without further treatment can overcome aggregation‐induced quenching effect, and emit stable bright blue luminescence under UV light irradiation in both colloidal and solid states. Additionally, the mechanism for the solid‐state fluorescence of CDs was also explored. Moreover, the feasibility of CDs as fluorescent labels for latent fingerprint detection was investigated and the results demonstrate well‐defined papillary ridges with higher sensitivity and wider applicability. The work provides a simple, low‐cost, and promising alternative for latent fingerprint detection in forensic science.
A Molecular Dynamics Study of the Inhibition of Monomeric HIV‐1 Protease as An Alternative to Overcome Drug Resistance by RNA Aptamers as A Therapeutic Tool
Authors: Ajamgard Marzieh , Sardroodi Jaber Jahanbin , Ebrahimzadeh Alireza Rastkar
Published: August 2020

Here, the interaction of three aptamers with HIV‐1 protease was investigated with the help of molecular dynamics simulations. These simulations led to precise structural and energetic results. The sequencing of the considered aptamers was AP1 as the aptamer number 1: (CUUCAUUGUAACUUCUCAUAAUUUCCCGAGGCUUUUACUUUCGGGGUCCU), AP2 as the aptamer number 2: (CCGGGUCGUCCCCUACGGGGACUAAAGACUGUGUCCAACCGCCCUCGCCU), and AP3 as the aptamer number 3: (C, U, A, G and UU nucleotides of AP1 were replaced with A, G, G, A and C to yield AP3). The results of molecular dynamics simulations showed that aptamers 2 and 3 were good alternatives to interact with the protease enzyme and to control this enzyme; however, in AP2 the results were somehow improved. The results of MM‐PBSA showed that although the aptamer 3 as a mutant aptamer had a good affinity with the protease enzyme, as compared to the aptamer 1, by impairing dimerization, it disrupted its structural stability and function. However, the results also indicated that the aptamer 2 could be a better inhibitor because it would cause a more severe conformational change in the structure of the enzyme.
Influence of Flame Retardants on LLDPE‐Date Pit Fiber Composites: Thermal Degradation and Tensile Properties
Authors: Gulati Kapil , Lal Sohan , Kumar Manish , Arora Sanjiv
Published: August 2020

Linear low density polyethylene (LLDPE)‐date pit composites incorporated with different flame retardants were synthesized by extrusion and casted into shape by injection moulding. Several additive type flame retardants viz. Ammonium polyphosphate (APP), Melamine phosphate (MP), Ammonium dihydrogen orthophosphate (ADOP), Diammonium hydrogen phosphate (DAHP) were added to enhance the flame retarding behaviour of composites. The thermal analysis and mechanical properties of composites have also been investigated. Thermogravimetric analysis (TGA) revealed a two step degradation mechanism of all the blends. The kinetic parameters such as activation energy and differential conversion function f(ɑ) were evaluated using three different non isothermal methods based on the iso conversional plots: Friedman (FM), Ozawa‐Flynn‐Wall (OFW) and Coats‐Redfern (Modified). The average value of activation energy of thermal degradation of blends evaluated using Friedman method; was used to depict the actual mechanism of degradation by fabricating the Criado's master plot. Addition of any kind of flame retardant led to an improvement in both tensile as well as flexural strength of composites. According to the results of Limiting Oxygen Index (LOI) and UL‐94 testing, addition of APP led to the significant improvement in the flame retardancy of LLDPE composites.
Fabrication and Analysis of ZnO Quantum Dots Based Easy Clean Coating: A Combined Theoretical and Experimental Investigation
Authors: Sethi Sushanta K. , Kadian Sachin , Anubhav  , Goel  , Chauhan Rishi Pal , Manik Gaurav
Published: August 2020

In this work, ZnO QD have been synthesized and later characterized using Transmission Electron Microscope (TEM) and X‐ray diffraction (XRD). XRD has confirmed the crystalline structure and TEM provided an average particle size of ∼6 nm. Further, ZnO QD with different wt. % were incorporated into poly(vinylacetate)‐graft‐poly(dimethylsiloxane) (PVAc‐g‐PDMS) base matrix and several performance properties like water contact angle (CA), transparency and surface behavior were assessed. Molecular dynamics simulation helped to demonstrate that vdW and valence energy effectively control filler‐matrix interactions and ZnO QD filler significantly enhanced matrix‐substrate interaction. For this, Gaussian distribution function has been utilized to model surface roughness of PVAc‐g‐PDMS/ZnO coatings with randomized filler dispersion. Experimentally, scanning electron microscope (SEM) confirmed the presence of dual (micro and nano) scale grooves by ZnO QD alone due to their limited agglomeration, which helped to enhance water repellency by ∼16 % without compromising with transparency. Theoretical investigations reveal that the coating, formulated from non‐health hazardous materials, possessed good transparency (>88 %), substrate adhesion (‐4045.33 kcal/mol), water (CA=109±2°) and decent oil (CA=69±2°) repellency, which agrees well with experimental results. Conclusively, 3 % ZnO QD in PVAc‐g‐PDMS is a useful coating material with optimal substrate adhesion, transparency and fluid repellency.
Encapsulation of Docetaxel into Diblock Polymeric Polymersome as a Nanodrug
Authors: Haghshenas Venus , Sariri Reyhaneh , Naderi Sohi Alireza , Nazari Hojjatollah
Published: August 2020

In this study, a chemotherapeutic drug, Docetaxel (DTX) was loaded in a di‐block polymeric nanoparticles (NPs) consisted of Oleate and Poly (ethylene glycol). First, the OA‐PEG1000 units were synthesized by the esterification reaction and confirmed by 1HNMR and FTIR spectroscopies. After determination of critical micelle concentration (CMC), the DTX was loaded into the OA‐PEG1000 NPs using the solvent displacement method. The encapsulation efficiency and loading capacity percentages were estimated as 22.2 % and 0.43 % respectively. The average size (obtained by DLS) and zeta potential of NPs were as 221.3±8.06 nm and 6.31±0.29 mV respectively indicating polymersome formation. The morphology of NPs in AFM images was almost spherical with a diameter of about 207.1±28.36 nm which was approximate to DLS outcomes. These results demonstrated that di‐block polymeric NPs can be potentially practical for carrying and delivering DTX as a novel anticancer pharmaceutical.
Green EmittingCe3+/ Tb3+‐Doped BaF2 Nanocrystals and Their Impact on Skeletal Muscle of Developing Zebrafish Larvae
Authors: Sharma Rahul Kumar , Chouryal Yogendra Nath , Nema Shubham , Nigam Sandeep , Bera Siba Prasad , Bhargava Yogesh , Ghosh Pushpal
Published: August 2020

An ionic liquid (IL)‐based solvothermal method is employed to prepare single‐phase, luminescent, cubic rare‐earth doped and silica‐coated BaF2 nanomaterials. High energy transfer efficiency (∼60%) from Ce3+ to Tb3+ for BaF2:Ce3+/Tb3+ nanoparticles dispersed in DMSO solution is observed. Furthermore, for the first time to the best of our knowledge, as‐prepared RE ion/s doped and silica‐coated BaF2 nanoparticles are used for the toxicological assessment on live zebrafish larvae. Interestingly, static exposure of these nanoparticles from 6 hpf till 96 hpf period at high concentration (70 mg/L) do not show any developmental anomalies as judged by bright‐field and birefringence optical imaging method which promises its large‐scale applications in imaging and other biological purposes.However, as a positive control, cypermethrin‐based pesticide could induce developmental defects at 0.1 mg/L concentration. It is worth mentioning that the concentration of BaF2 nanoparticles chosen in present study is much higher than the other nanoparticles reported so far.
Synthesis and Luminescent Properties of Functionalized Bipyridyl Based Eu Complexes
Authors: Krinochkin Alexey P. , Kopchuk Dmitry S. , Kim Grigory A. , Shevyrin Vadim A. , Tseitler Tatyana A. , Santra Sougata , Kovalev Igor S. , Zyryanov Grigory V. , Rusinov Vladimir L. , Chupakhin Oleg N.
Published: August 2020

5‐(4‐(Het)arylphenyl)‐2,2′‐bipyridine‐6‐carboxylic acids were synthesized as ligands for the neutral lanthanide complexes by using the “1,2,4‐triazine” approach and Suzuki or Stille cross‐coupling reaction with intermediate 5‐(4‐bromophenyl)‐2,2′‐bipyridine‐6‐carbonitrile. The neutral europium complexes of these ligands were obtained with 3 : 1 stoichiometric amount. The photophysical properties of the synthesized complexes were studied, and the influence of the nature of the aryl substituent was estimated. In some cases the improvement of the photophysical characteristics has been demonstrated for the complexes in case of addition of extra phenyl ring in the structure of the ligand.
Claisen‐Schmidt Condensation using Green Catalytic Processes: A Critical Review
Authors: Yadav Ganapati D. , Wagh Dipti P.
Published: August 2020

Claisen‐Schmidt condensation have historical significance for over140 years and the scope was expanded due to the realization that chalcones so synthesized possess biological activity. The principles of green chemistry with emphasis on use of different solid catalysts with proper distribution of active centers such as acid, base, acid‐base, organo‐ were used along with solvent‐less systems. Among solid bases layered double hydroxides (LDH)/hydrotalcites are the most common. The limitations of solid bases are overcome by solid acids and superacids. A number of metal oxide supports are used. MOFs are increasingly being used. Complex organo‐catalysts are employed for getting excellent regio‐selectivity. In certain metal oxides, both acidic and basic sites co‐exist on the pore surface of catalyst which offer superior results. Synergism of solid catalysis using microwaves and ultrasound to intensify rates and selectivity is in vogue.Controlled pore structure and distribution of active catalytic centers, whether mono‐, bi‐ or tri‐functional catalysts, will give better green and smart processes. The review gives a critical analysis of the area and presents future directions for research.
A New Aliphatic Ketone, Chemical Composition, Antibacterial, Antioxidant and In Vitro Cytotoxic Activities of Lepidium latifolium
Authors: Feng Yan , Assani Israa , Wang Chun‐Gu , Hou Pei‐Lei , Zhao Shi‐Feng , Ye Hao‐Jie , Li Rui‐Chen , Zhang Jin‐Bin , Liao Zhi‐Xin
Published: August 2020

One new aliphatic ketone alcohol, 15,17‐dione‐16‐hentriacontanol (1), with fifteen known compounds (2–16) were isolated from the ethanolic extract of the whole dried plant of Lepidium latifolium. The antibacterial activities (using minimum inhibitory concentrations (MIC) detection method), the antioxidant activities (using 1,1‐diphenyl‐2‐picrylhydrazyl radical (DPPH) and pyrogallol), and the antiproliferative activities (using 3‐(4,5‐dimethyl‐2‐thiazolyl)‐2,5‐diphenyl‐2‐H‐tetrazolium bromide (MTT) method) against three human cancer cell lines were evaluated. The results showed that compounds 2, 9, 10 and 11 with phenolic hydroxyl groups have good antibacterial and DPPH scavenging activities. Compounds 2, 12 and 13, which contain ‐NH groups have the highest scavenging rates of superoxide anions. The compounds of long‐chain alkane containing hydroxyl groups have potent inhibitory activity against MGC‐803, HepG2 and T24 cancer cells. The experimental content of this paper enriches the related research of L. latifolium, and greatly expands the market application value of the plant.
Novel and Green Preparation of Fe3O4@TiO2‐Immobilized‐ILs Based on DABCO for Highly Efficient Synthesis of Primido[4,5‐d]pyrimidines
Authors: Ghasemzadeh Mohammad Ali , Bakhshali‐Dehkordi Raziyeh
Published: August 2020

Recently, ionic liquids immobilized on magnetic nanoparticles (MNPs) have drawn increasing attentions in organic synthesis and separation technologies and gained substantial progresses. In this study, the Fe3O4@TiO2@ILs nanocatalyst was first synthesized and characterized by using techniques such as Fourier transform infrared spectroscopy (FT‐IR), energy‐dispersive X‐ray (EDX), vibrating sample magnetometer (VSM), field emission scanning electron microscopy (FE‐SEM), powder X‐ray diffraction (XRD), thermogravimetric analysis (TGA) and transmission electron microscopy (TEM). The efficiency of the nanocatalyst was investigated in the preparation of pyrimido[4,5‐d]pyrimidine derivatives under solvent‐free conditions. The nanocatalyst demonstrated excellent catalytic activity and the products were synthesized in good to excellent yields. Moreover, the recoverability and reusability of the catalyst were investigated to show the effect of ionic liquid moieties on the stabilization of Fe3O4@TiO2@ILs species during the reactions. Our study showed that the nanocatalyst could be recovered and reused at least seven times without any appreciable decrease in activity which confirmed its high efficiency and high stability under the reaction conditions.
Theoretical Study of VX Hydrolysis Mechanism Catalyzed by Phosphotriesterase Mutant H254R
Authors: Zheng Yong‐Chao , Su Jing‐Xuan , Zheng He , Li Sheng‐Song , Zhao Chong‐Lin , Chen Li‐Kun , Zhong Jin‐Yi , Chen Shi‐Lu
Published: August 2020

Phosphotriesterase (PTE) is a bacterial enzyme that can catalyze the hydrolysis of V‐type chemical warfare nerve agents. Herein, the hydrolysis mechanism of VX analogs catalyzed by the H254R PTE mutant, in which the histidine 254 residue is replaced by an arginine, has been investigated using the hybrid density functional theory method B3LYP. The chemical model of the active site of H254R PTE mutant was constructed based on the high resolution X‐ray crystal structure. We have presented the energetics and the characterization of stationary points in the catalytic reaction. The calculations indicate that the catalytic process contain two SN2 displacement steps and the step of hydroxide regeneration is rate‐limiting with an overall barrier of 22.2 kcal/mol. The Arg254 plays an important role as a proton donor/acceptor for protonating leaving group and activating water molecule. Moreover, the H254R PTE mutant with binuclear cobalt center turns out to higher activity towards VX than the binuclear zinc H254R PTE.
Metal‐Free, H2O2‐Mediated, Regioselective Direct C‐3 Hydroxylation of Imidazo[1,2‐a]pyridines via C(sp2)‐H Bond Functionalization
Authors: Kant Yadav Ravi , Kumar Yogesh , Chaudhary Sandeep
Published: August 2020

For the first time, a new, cost‐effective, metal‐free, H2O2 (50 % in water)‐mediated regioselective direct C‐3 hydroxylation of imidazo[1,2‐a]pyridines via C‐H bond functionalization is reported. This metal‐free C(sp2)‐O bond formation protocol is operationally simple and showed broad range of functional group tolerance and substrate affinity. To the best of our knowledge, this is the first report of imidazo[1,2‐a]pyridine‐3‐ols showing promising in vitro antioxidant activity.
Poisoning Effect Comparison of ZnCl2 and ZnSO4 on Mn‐Ce/AC Catalyst for Low‐Temperature SCR of NO
Authors: Su Zenghui , Ren Shan , Yang Jie , Yao Lu , Zhou Yuhan , Chen Zhichao , Zhang Tianshi
Published: August 2020

In this study, the effect of different zinc salts (ZnCl2 and ZnSO4) on the deactivation of activated carbon(AC)‐based Mn−Ce catalysts and the poisoning mechanism of zinc salts on Mn−Ce/AC are comparatively studied. SEM, BET, XRD, XPS, H2‐TPR, NH3‐TPD and In‐situ DRIFT are used to characterize the physical and chemical changes of Mn−Ce/AC catalyst. The Selective Catalytic Reduction (SCR) activities of Mn−Ce/AC has a noticeable decline after loading zinc salts, and the highest NO conversion of Zn poisoning catalysts do not exceed 70 %. And the acid site is occupied by Zn2+ on the catalyst, which affects the chemical adsorption of NH3 and hinders the formation of the intermediate ‐NH2. Moreover, the decrease of Mn4+, reducibility of manganese oxide and acid sites are more serious on ZnC−Mn‐Ce/AC. Besides, loading ZnSO4 can improve the content of Ce3+ and Oβ on catalyst surface, which can mitigate the poisoning effects of ZnSO4 on Mn−Ce/AC catalyst. Hence, ZnCl2 displays a more serious poisoning effect on Mn−Ce/AC catalyst compared with ZnSO4. Then the probable mechanism model of ZnCl2 and ZnSO4 on Mn−Ce /AC catalyst is proposed and compared.
A Practical Synthesis of 3‐Functionalized Coumarins from o‐Cresols and Active Methylene Compounds under Metal and Catalyst‐Free Conditions Using tert‐Butyl Hydrogen Peroxide
Authors: Chauhan Swati , Verma Pratibha , Kandasamy Jeyakumar , Srivastava Vandana
Published: August 2020

An efficient synthesis of 3‐functionalized coumarins is demonstrated from o‐cresols and active methylene compounds under solvent‐, metal‐ and catalyst‐free conditions in the presence of 70 % aqueous tert‐butyl hydrogen peroxide. The important features of this protocol are operational simplicity, mild reaction conditions and good to excellent yield of the products.
Modification of Molecular Sieves USY and Their Application in the Alkylation Reaction of Benzene with Cyclohexene
Authors: Meng Fanfei , Ding Yuansheng , Meng Wei , Mi Guangyi , Qiu Jun
Published: August 2020

In this manuscript, ultrastable Y (USY) zeolites are modified employing a liquid‐phase ion exchange method to furnish H‐USY with different properties. Modified with ammonium nitrate, H‐USY could largely improve the conversion in the alkylation reaction of benzene with cyclohexene due to the increase in Brunauer‐Emmett‐Teller (BET) specific surface area, Barrett‐Joyner‐Halenda (BJH) pore volume, BJH pore size, and acidity of H‐USY. Catalyzed by the molecular sieve modified twice with ammonium nitrate, this alkylation reaction demonstrated a 95.3 % conversion of cyclohexene with 97.4 % selectivity of cyclohexylbenzene. And we found that urea‐modified USY has the similar effect, a 96.1 % conversion of cyclohexene with slightly 94.9 % selectivity of cyclohexylbenzene.
Application of Palladium Based Precatalytic Systems in the Suzuki‐Miyaura Cross‐Coupling Reactions of Chloro‐ Heterocycles
Authors: Bhaskaran Savitha , Padusha M. Syed Ali , Sajith Ayyiliath M
Published: August 2020

Carbon‐Carbon bond forming reactions using Suzuki‐Miyaura cross‐coupling (SMC) technology to construct aryl‐aryl, aryl‐heteroaryl or heteroaryl‐heteroaryl linkages continues to play a vital role in pharmaceuticals, agrochemicals, material science and manufacturing fields. The importance of Suzuki‐Miyaura cross‐coupling which is also reflected in their use in industrial applications, warrants the development of highly efficient catalytic systems that allows the cross‐coupling of economically attractive heteroaryl chlorides. Conversely, the low reactivity of heteroaryl chlorides followed by problems associated with multi‐heteroatom systems amplifies the difficulties involved in SMC procedures. This review focuses on the developments made in the palladium mediated SMC of chloro heterocycles using various palladium/Ligand combinations and highlights the significant improvements achieved by the use of Buchwald's palladium precatalysts.
High Cycling Performance Li‐S Battery via Fenugreek Gum Binder Through Chemical Bonding of the Binder with Polysulfides in Nanosulfur@CNFs Cathode
Authors: Mo Yu‐Xue , Wu Yi‐Jin , Yin Zu‐Wei , Ren Wen‐Feng , Gao Zhen‐Guang , Zhang Peng‐Fang , Lin Jin‐Xia , Zhou Yao , Li Jun‐Tao , Huang Ling , Sun Shi‐Gang
Published: August 2020

The dissolution and diffusion of lithium polysulfides are one of the main intrinsic bottlenecks in the development of lithium‐sulfur (Li−S) batteries with long term cycling stability. Appropriate binders could play a key role of anchoring the lithium polysulfides in S‐cathode through strong chemical bonds, thus boosts the electrochemical performance of Li−S battery. Herein, we report a new binder (fenugreek gum, FG) that has enhanced significantly the cycling performance of Li−S batteries with S@CNFs composite as cathode. The Li−S cell with FG binder delivers a large initial capacity of 900 mAh g−1 at 2 C, and a reversible capacity retention of 45.6 % after 1300 cycles, superior to the cycling performance of Li−S cell with conventional PVDF or previous reported guar gum (GG) binder. This enhancement in cycling performance of Li−S batteries could be attributed to the formation of the S−O and Li−O bonds between the O‐relevant functional groups in the binder and the polysulfides in S‐cathode as manifested by XPS data of the discharged and charged electrodes. Furthermore, the tensile strain rate of the FG binder is as high as 32 %, which can effectively restrain the volume expansion of the S‐cathode during the discharge/charge process and ensure the integrity of the electrode.
Effects of Small Molecule Interlayer Engineering in Vanadium Oxide for Zinc Ion Battery
Authors: Yin Bosi , Zhang Siwen , Ke Ke , Vincent Lee Wee Siang , Wang Zhenbo
Published: August 2020

Vanadium oxide has great potential in the development of battery technology. However, there are several key flaws, such as low rate performance and poor cyclic stability, that require urgent attention for such material. In view of these challenges, this work proposes a strategy to optimize the interlayer spacing of vanadium oxide framework so as to improve its electrochemical performance. In this work, vanadium‐oxide is modified with small molecules as molecular pillars, and through this method the as‐prepared NH4V4O10 is able to exhibit a larger interlayer spacing of 9.6 Å. This expanded interlayer spacing is particularly advantageous as it allows host material to accommodate more Zn2+ and to facilitate their migration. The as‐assembled Zn//NH4V4O10 (denoted as NVO) is able to deliver a capacity of 430 mAh g−1 at current density of 1 A g−1. A good cyclic retention of 85 % is achieved for Zn//NVO after deep cycling for 2000 cycles at 1 A g−1. Thus, based on the collective results, introducing small molecules into the interlayer spacing could be an advantageous strategy in improving the performance of the electrode effectively.
Ultrathin CIGSe Solar Cells with Integrated Structured Back Reflector
Authors: Schneider Thomas , Tröndle Johanna , Fuhrmann Bodo , Syrowatka Frank , Sprafke Alexander , Scheer Roland
Published: August 2020

To reduce the thickness of CuIn1‐xGaxSe2 (CIGSe) solar cells, light management concepts must be used. One concept is the combination of an Al/indium1‐tin1‐oxide (ITO) reflector/contact and an optical scattering element at the back side of the device. Herein, nanostructured substrates, obtained by laser interference lithography and lift‐off process, are covered with an Al/ITO back contact. Structure dimensions are a pitch of 1.96 μm and heights of 100–700 nm. Solar cells with 600 nm CIGSe absorber having this integrated structured back reflector exhibit an increase in JSC of up to 3.2 mA cm−2 compared with the Mo reference sample of identical thickness. To understand this optical gain, 3D finite‐difference time‐domain (FDTD) simulations are performed. To this end, a model is built to simulate structure formation. It is shown that locally enhanced optical absorption can be achieved by the integrated structured back reflector. It is also shown that parasitic absorption in the back ITO diffusion barrier needs to be minimized.
Dopant‐Free and Green‐Solvent‐Processable Hole‐Transporting Materials for Highly Efficient Inverted Planar Perovskite Solar Cells
Authors: Meng Fei , Wang Yunhao , Wen Yaping , Lai Xue , Li Wenhui , Kyaw Aung Ko Ko , Zhang Ren , Fan Dongyu , Li Yuheng , Du Mengzhen , Guo Xiao , Ma Haibo , Li Gongqiang , Sun Xiao Wei , Wang Jianpu
Published: August 2020

Two saddle‐shaped hole‐transporting materials (HTMs), α, β‐COTh‐Ph‐OMeTAD and β, β‐COTh‐Ph‐OMeTAD are designed with a strategy of flexible core with tunable conformation (FCTC) and applied in inverted planar perovskite solar cells (PSCs) as dopant‐free HTMs. As a result, the device based on α, β‐COTh‐Ph‐OMeTAD demonstrates a high power conversion efficiency (PCE) of 17.59% with Jsc = 21.32 mA cm−2, Voc = 1.02 V, and FF = 80.75%, and the one based on β, β‐COTh‐Ph‐OMeTAD yields a higher PCE of 18.53% with Jsc = 22.68 mA cm−2, Voc = 1.04 V, and FF = 78.48%. Moreover, the green‐solvent‐processed PSCs are also fabricated by dissolving the HTMs in ethyl acetate. Without any encapsulation, the devices based on both HTMs retain 80% of their initial PCEs after storage for 150 days in a glove box, and 60% of their initial PCEs after storing for 300 h in ambient air with 40% relative humidity. All these results demonstrate that the materials α, β‐COTh‐Ph‐OMeTAD and β, β‐COTh‐Ph‐OMeTAD based on FCTC strategy are promising HTMs for highly efficient and stable PSCs.
Interlocked Dual‐Network and Superelastic Electrospun Fibrous Sponges for Efficient Low‐Frequency Noise Absorption
Authors: Zong Dingding , Cao Leitao , Li Yuyao , Yin Xia , Si Yang , Yu Jianyong , Ding Bin
Published: August 2020

Traffic noise is a major source of urban noise pollution, with severe threats to the physiological and psychological health of humans. Fibrous sound absorption materials are extensively applied in the control of traffic noise pollution; however, the larger fiber diameters and monotonous internal structure of such materials result in poor low‐frequency sound‐absorbing properties or unsatisfied mechanical properties. Herein, a biomimetic and robust strategy to design ultrastrong and superelastic fibrous sound absorption sponges is reported, which is achieved by integrating a one‐step forming technique of interlocked micro/nano dual fiber networks and an in situ crosslinking approach. The obtained vine‐like interlocked structured fibrous sponges can withstand a tensile force 10 000 times their weight without deformation. Furthermore, the materials also show outstanding compression fatigue resistance and a lightweight feature (8.70 mg cm−3). Most importantly, the interlocked dual‐network‐induced stable fluffy‐stacked structure endows the fibrous sponges with an enhanced low‐frequency sound‐absorbing property (absorption coefficient of 0.93 at 1000 Hz), which is superior to those of commercial and reported sound absorption materials. In addition, the materials also possess good hydrophobicity and temperature resistance. This work opens new pathways for the further development of highly efficient sound‐absorbing materials.
Influence of compressive stress on chloride transport in the interfacial zone of precast and cast‐in‐place concrete
Authors: Zhao Jie , Li Fumin , Luo Xiaoya
Published: August 2020

The large number of interfacial zones of precast and cast‐in‐place concrete weakens the durability and resistance to chloride penetration of fabricated structures. This study investigated the chloride transport behavior in the interfacial zone of precast and cast‐in‐place concrete through long‐term wet–dry cycle experiments. The two influencing factors of compressive stress and distance to the interface were investigated. A chloride concentration test was conducted to investigate the chloride distribution profile, the chloride diffusion coefficient Dapp, and the surface chloride concentration Cs,∆x. The values of Dapp and Cs,∆x correlated with both the location in the interfacial zone and compressive stress, and both dependencies showed complex interactions. All specimens showed different degrees of this interfacial zone effect, which was weakened by compressive stress. Based on the test results, empirical models were developed (by regression) to quantify the dependences of Dapp and Cs,∆x to both compressive stress level and distance to the interface. Applicability of the models was verified.
Strengthening of RC beams using the combination of EB CFRP sheet, NSM CFRP bar and P‐SWRs
Authors: Zeng Yihua , Chen Xi , Li Xinghua , Wu Gang
Published: August 2020

Debonding issues in the externally bonded (EB) CFRP sheets (or near‐surface mounted [NSM] CFRP bars) and space requirements of edge and spacing clearances for NSM CFRP bars (or the prestressed steel wire ropes [P‐SWRs]) have limited the applications of these strengthening techniques. The combination of these techniques may overcome the drawbacks of each technique and was experimentally and analytically investigated in this paper. Test results demonstrated that the flexural performances of the combinedly strengthened beam are between the flexural performances of the beams strengthened with the corresponding individual strengthening techniques. It is found the combination of the three techniques successfully prevented debonding issues which often occur in EB or NSM techniques and improved the spacing and edge clearances which are necessary for NSM and P‐SWRs techniques. In addition, the combination was demonstrated as effective to limit the crack development and improve the ductility of the strengthened beams.
Use of titanate to improve interfacial interaction and mechanical properties of polyethylene/artificial marble wastes composites
Authors: Lu Honglang , Chen Keyu , Yang Xin , Liu Jize , Huang Xin , Lv Zhen , Zhang Xinxing
Published: August 2020

The resource utilization of artificial marble wastes (AMWs) is urgently needed for environmental protection as a large amount of artificial marble are used as construction material. Nevertheless, it still remains challenging to achieve high performance of AMWs‐filled polymer composites due to their poor interfacial interaction with hydrophobic polyolefins. Here, the unsaturated resin residue on the surface of AMWs is employed to construct strong interfacial interaction with high‐density polyethylene (HDPE) matrix to prepare mechanically robust polymeric composites by use of titanate coupling agent. The mechanical properties (with a tensile strength of 28.6 MPa and a flexural strength of 27.7 MPa) of the resulting composites are comparable to or even better than those of raw calcium carbonate‐filled HDPE composites. This work will not only promote the recycling and reutilization of AMWs, but also provide a feasible way for value‐added application of other polymeric wastes, such as waste printed circuit board, waste artificial turf, and so on.
Defects of full-length dystrophin trigger retinal neuron damage and synapse alterations by disrupting functional autophagy
Authors: Catalani Elisabetta , Bongiorni Silvia , Taddei Anna Rita , Mezzetti Marta , Silvestri Federica , Coazzoli Marco , Zecchini Silvia , Giovarelli Matteo , Perrotta Cristiana , De Palma Clara , Clementi Emilio , Ceci Marcello , Prantera Giorgio , Cervia Davide
Published: August 2020

Dystrophin (dys) mutations predispose Duchenne muscular disease (DMD) patients to brain and retinal complications. Although different dys variants, including long dys products, are expressed in the retina, their function is largely unknown. We investigated the putative role of full-length dystrophin in the homeostasis of neuro-retina and its impact on synapsis stabilization and cell fate. Retinas of mdx mice, the most used DMD model which does not express the 427-KDa dys protein (Dp427), showed overlapped cell death and impaired autophagy. Apoptotic neurons in the outer plexiform/inner nuclear layer and the ganglion cell layer had an impaired autophagy with accumulated autophagosomes. The autophagy dysfunction localized at photoreceptor axonal terminals and bipolar, amacrine, and ganglion cells. The absence of Dp427 does not cause a severe phenotype but alters the neuronal architecture, compromising mainly the pre-synaptic photoreceptor terminals and their post-synaptic sites. The analysis of two dystrophic mutants of the fruit fly Drosophila melanogaster, the homozygous DysE17 and DysEP3397, lacking functional large-isoforms of dystrophin-like protein, revealed rhabdomere degeneration. Structural damages were evident in the internal network of retina/lamina where photoreceptors make the first synapse. Both accumulated autophagosomes and apoptotic features were detected and the visual system was functionally impaired. The reactivation of the autophagosome turnover by rapamycin prevented neuronal cell death and structural changes of mutant flies and, of interest, sustained autophagy ameliorated their response to light. Overall, these findings indicate that functional full-length dystrophin is required for synapsis stabilization and neuronal survival of the retina, allowing also proper autophagy as a prerequisite for physiological cell fate and visual properties.