bluuebunny/crossref_metadata_2025_split huggingface dataset:
Functional Enzyme Mimics for Oxidative Halogenation Reactions that Combat Biofilm Formation
Authors: Herget Karoline , Frerichs Hajo , Pfitzner Felix , Tahir Muhammad Nawaz , Tremel Wolfgang 
Published: June 2018

AbstractTransition‐metal oxide nanoparticles and molecular coordination compounds are highlighted as functional mimics of halogenating enzymes. These enzymes are involved in halometabolite biosynthesis. Their activity is based upon the formation of hypohalous acids from halides and hydrogen peroxide or oxygen, which form bioactive secondary metabolites of microbial origin with strong antibacterial and antifungal activities in follow‐up reactions. Therefore, enzyme mimics and halogenating enzymes may be valuable tools to combat biofilm formation. Here, halogenating enzyme models are briefly described, enzyme mimics are classified according to their catalytic functions, and current knowledge about the settlement chemistry and adhesion of fouling organisms is summarized. Enzyme mimics with the highest potential are showcased. They may find application in antifouling coatings, indoor and outdoor paints, polymer membranes for water desalination, or in aquacultures, but also on surfaces for food packaging, door handles, hand rails, push buttons, keyboards, and other elements made of plastic where biofilms are present. The use of natural compounds, formed in situ with nontoxic and abundant metal oxide enzyme mimics, represents a novel and efficient “green” strategy to emulate and utilize a natural defense system for preventing bacterial colonization and biofilm growth.
“Dual Lock‐and‐Key”‐Controlled Nanoprobes for Ultrahigh Specific Fluorescence Imaging in the Second Near‐Infrared Window
Authors: Tang Yufu , Li Yuanyuan , Hu Xiaoming , Zhao Hui , Ji Yu , Chen Liang , Hu Wenbo , Zhang Wansu , Li Xiang , Lu Xiaomei , Huang Wei , Fan Quli 
Published: June 2018

AbstractFluorescence imaging in the second near‐infrared window (NIR‐II) is a new technique that permits visualization of deep anatomical features with unprecedented spatial resolution. Although attractive, effectively suppressing the interference signal of the background is still an enormous challenge for obtaining target‐specific NIR‐II imaging in the complex and dynamic physiological environment. Herein, dual‐pathological‐parameter cooperatively activatable NIR‐II fluorescence nanoprobes (HISSNPs) are developed whereby hyaluronic acid chains and disulfide bonds act as the “double locks” to lock the fluorescence‐quenched aggregation state of the NIR‐II fluorescence dyes for performing ultrahigh specific imaging of tumors in vivo. The fluorescence can be lit up only when the “double locks” are opened by reacting with the “dual smart keys” (overexpressed hyaluronidase and thiols in tumor) simultaneously. In vivo NIR‐II imaging shows that they reduce nonspecific activitation and achieve ultralow background fluorescence, which is 10.6‐fold lower than single‐parameter activatable probes (HINPs) in the liver at 15 h postinjection. Consequently, these “dual lock‐and‐key”‐controlled HISSNPs exhibit fivefold higher tumor‐to‐normal tissue ratio than “single lock‐and‐key”‐controlled HINPs at 24 h postinjection, attractively realizing ultrahigh specificity of tumor imaging. This is thought to be the first attempt at implementing ultralow background interference with the participation of multiple pathological parameters in NIR‐II fluorescence imaging.
Hierarchical Nanoporous Copper Fabricated by One‐Step Dealloying Toward Ultrasensitive Surface‐Enhanced Raman Sensing
Authors: Song Ruirui , Zhang Ling , Zhu Fan , Li Wei , Fu Zhenchuang , Chen Bin , Chen Mingwei , Zeng Heping , Pan Deng 
Published: June 2018

AbstractGeometry‐tunable substrates with abundant plasmon resonant structure are ideal to proffer high surface‐enhanced Raman scattering (SERS) activity for trace sensing including pollutants and toxics, whereas great challenge remains in creating high‐density “hotspots” in these structures for further improving Raman signals and detection sensitivity. Herein, one‐step dealloying strategy is proposed to fabricate free‐standing copper membranes with hierarchical porous architecture where a high density of inherent “hotspots” is built in the vicinity of secondary pores in 3D ligaments. The hierarchical nanoporous copper shows excellent SERS activity with an average enhancement factor of 6.4 × 109, originating from strong electromagnetic coupling effects induced by its highly dense “hotspots” and highly accessible surface. Moreover, the proposed one‐step dealloying strategy of dual‐phase binary alloys propounds an inexpensive yet effective route to construct ultrasensitive SERS substrate for trace detection and molecular diagnosis.
Dynamic Impact of Electrode Materials on Interface of Single‐Crystalline Methylammonium Lead Bromide Perovskite
Authors: Tisdale Jeremy T. , Muckley Eric , Ahmadi Mahshid , Smith Travis , Seal Cody , Lukosi Eric , Ivanov Ilia N. , Hu Bin 
Published: June 2018

AbstractOne of the current challenges in methylammonium lead halide (MAPbX3) perovskite application research is understanding contact formation and interfacial phenomena for highly efficient and stable device performance. For semiconductors, development of contact formation is inseparable from device performance and stability. Single‐crystalline MAPbX3 has become of great interest for perovskite devices in photodetectors, light‐emitting diodes, and more recently in high‐energy radiation detection. Deeper research is required to understand interfacial interactions in single‐crystalline MAPbX3. This article focuses on the dynamic impact of electrode metal (Au and Cr) on methylammonium lead bromide (MAPbBr3) single crystals. It is studied how charge transport properties of single crystal MAPbBr3 can be tuned via electrode material selection at the metal/MAPbBr3 interface to improve device performance with proper contact formation. The ability to create an ohmic‐like or nonohmic contact by switching the electrode metal from Cr to Au, respectively, is demonstrated. It is observed that the interfacial charge transfer resistance (recombination resistance) of the Cr/MAPbBr3 interface is 1.79  ×  109 Ω, compared to 1.32  ×  107 Ω for the Au/MAPbBr3. Cr contacts can reduce hysteretic behavior by reducing interfacial recombination and interfacial polarization. These studies provide insight to metal/MAPbX3 interfacial interactions toward device engineering for hole transport layer‐free MAPbX3 device structures.
The effects of plant sexual system and latitude on resistance to herbivores
Authors: Rivkin L. R. , Barrett Spencer C. H. , Johnson Marc T. J. 
Published: June 2018

Premise of the StudyThe strength of plant‐herbivore interactions varies in space and time, but the factors that explain this variation are poorly understood. Several lines of research suggest that variation in plant reproductive systems and latitude may explain resistance against herbivores, but how these factors jointly affect plant‐herbivore interactions has not been investigated in detail. We examined the effects of latitude, sexual system, and plant gender on herbivory in Sagittaria latifolia, an aquatic plant in which populations are typically monoecious (separate female and male flowers) or dioecious (separate female and male plants).MethodsWe surveyed 43 populations of S. latifolia between 42 and 48° N in Ontario, Canada. In each population, we recorded the sexual system and obtained estimates of herbivore damage to ramets of known gender (i.e. female, male, or hermaphrodite) by the weevil Listronotus appendiculatus, the principal herbivore of S. latifolia. Herbivore damage was quantified as the percent leaf area removed by adult L. appendiculatus weevils, and the abundance of larvae feeding within flowering stalks, which was correlated with the amount of damage by herbivores to the inflorescence.Key ResultsLeaf herbivory significantly decreased with increasing latitude but did not vary with sexual system or plant gender. By contrast, larvae were more abundant in dioecious populations and on female plants, corresponding to increased stem damage, providing evidence for sex‐biased larval abundance in S. latifolia. These effects of sexual system and gender on larval abundance were strongest at lower latitudes.ConclusionsOur study found latitudinal variation in leaf herbivory and sex‐biased resistance to weevil larvae that feed on the reproductive tissues of S. latifolia, which is predicted to be a necessary condition for herbivory to influence the evolution of dioecy.
Iron Porphyrins Embedded into a Supramolecular Porous Organic Cage for Electrochemical CO2 Reduction in Water
Authors: Smith Peter T. , Benke Bahiru Punja , Cao Zhi , Kim Younghoon , Nichols Eva M. , Kim Kimoon , Chang Christopher J. 
Published: June 2018

AbstractA porous organic cage composed of six iron tetraphenylporphyrins was used as a supramolecular catalyst for electrochemical CO2‐to‐CO conversion. This strategy enhances active site exposure and substrate diffusion relative to the monomeric catalyst, resulting in CO generation with near‐quantitative Faradaic efficiency in pH 7.3 water, with activities reaching 55 250 turnovers. These results provide a starting point for the design of supramolecular catalysts that can exploit the properties of the surrounding matrix yet retain the tunability of the original molecular unit.
Precise Activation of Ammonia and Carbon Dioxide by an Iminodisilene
Authors: Wendel Daniel , Szilvási Tibor , Henschel Daniel , Altmann Philipp J. , Jandl Christian , Inoue Shigeyoshi , Rieger Bernhard 
Published: June 2018

AbstractThe activation of NH3 and CO2 is still an ambitious target for multiply bonded sub‐valent silicon compounds. Now, the precise splitting of the N−H bond of ammonia by (Z)‐imino(silyl)disilene 1 to give trans‐1,2‐adduct 2 a at low temperatures (−78 °C) is presented. According to DFT calculations, the stereospecific hydroamination follows a similar mechanism as the recently reported anti‐addition of H2 to the Si=Si bond of 1. The aminosilane 2 b could also be obtained as the formal silylene addition product under thermodynamic reaction control. By applying low temperatures, the activation of CO2 with 1 selectively afforded the cis‐oxadisilacyclobutanone 7‐c as [2+2] cycloadduct. By performing the reaction directly at ambient temperatures, a mixture of three different‐sized silacycles (4–6) was observed. Their formation was investigated theoretically and their structures were revealed with separate experiments using 1 and the oxygenation agents N2O and O2.
Efficient Oxygen Reduction Reaction (ORR) Catalysts Based on Single Iron Atoms Dispersed on a Hierarchically Structured Porous Carbon Framework
Authors: Zhang Zhengping , Sun Junting , Wang Feng , Dai Liming 
Published: June 2018

AbstractSingle Fe atoms dispersed on hierarchically structured porous carbon (SA‐Fe‐HPC) frameworks are prepared by pyrolysis of unsubstituted phthalocyanine/iron phthalocyanine complexes confined within micropores of the porous carbon support. The single‐atom Fe catalysts have a well‐defined atomic dispersion of Fe atoms coordinated by N ligands on the 3D hierarchically porous carbon support. These SA‐Fe‐HPC catalysts are comparable to the commercial Pt/C electrode even in acidic electrolytes for oxygen reduction reaction (ORR) in terms of the ORR activity (E1/2=0.81 V), but have better long‐term electrochemical stability (7 mV negative shift after 3000 potential cycles) and fuel selectivity. In alkaline media, the SA‐Fe‐HPC catalysts outperform the commercial Pt/C electrode in ORR activity (E1/2=0.89 V), fuel selectivity, and long‐term stability (1 mV negative shift after 3000 potential cycles). Thus, these nSA‐Fe‐HPCs are promising non‐platinum‐group metal ORR catalysts for fuel‐cell technologies.
E5M7+ (E=C–Pb, M=Li–Cs): A Source of Viable Star‐Shaped Clusters
Authors: Vásquez‐Espinal Alejandro , Palacio‐Rodríguez Karen , Ravell Estefanía , Orozco‐Ic Mesías , Barroso Jorge , Pan Sudip , Tiznado William , Merino Gabriel 
Published: June 2018

AbstractHerein we report the systematic exploration of the potential energy surfaces of a series of clusters with formula E5M7+ (E=C‐Pb and M=Li‐Cs). Fifteen of these combinations adopt a D5h three‐dimensional seven‐pointed star‐like structure in a singlet state, where M atoms interact electrostatically with the E5 ring. The determining factors in the relative preference of having the D5h structure over the most competitive isomer or vice‐versa are analyzed. These star‐shaped systems satisfy the 4n+2 Hückel's rule and exhibit a strong diatropic (σ and π) response to an external magnetic field.
Developing a Self‐Healing Supramolecular Nucleoside Hydrogel Based on Guanosine and Isoguanosine
Authors: Tang Fan , Feng Hui , Du Yuqi , Xiao Yandi , Dan Hongxia , Zhao Hang , Chen Qianming 
Published: June 2018

AbstractRecently, supramolecular hydrogels have attracted increasing interest owing to their tunable stability and inherent biocompatibility. However, only few studies have been reported in the literature on self‐healing supramolecular nucleoside hydrogels, compared to self‐healing polymer hydrogels. In this work, we successfully developed a self‐healing supramolecular nucleoside hydrogel obtained by simply mixing equimolar amounts of guanosine (G) and isoguanosine (isoG) in the presence of K+. The gelation properties have been studied systematically by comparing different alkali metal ions as well as mixtures with different ratios of G and isoG. To this end, rheological and phase diagram experiments demonstrated that the co‐gel not only possessed good self‐healing properties and short recovery time (only 20 seconds) but also could be formed at very low concentrations of K+. Furthermore, nuclear magnetic resonance (NMR), powder X‐ray diffraction (PXRD), and circular dichroism (CD) spectroscopy suggested that possible G2isoG2‐quartet structures occurred in this self‐healing supramolecular nucleoside hydrogel. This co‐gel, to some extent, addressed the problem of isoguanosine gels for the applications in vivo, which showed the potential to be a new type of drug delivery system for biomedical applications in the future.
EISA (Energy Independence and Security Act) compliant ethanol fuel from corn stover in a depot‐based decentralized system
Authors: Kim Seungdo , Zhang Xuesong , Dale Bruce E. , Reddy Ashwan D. , Jones Curtis D. , Izaurralde Roberto C. 
Published: June 2018

AbstractCellulosic biofuels face significant problems of feedstock aggregation and logistics leading to poor economies of scale. The current model is for relatively small biorefineries using feedstock gathered locally. Here a depot‐based decentralized biorefinery system is explored to estimate the US Energy Independence and Security Act (EISA) compliant corn stover ethanol production potential in the US Midwest. Depots serve to aggregate, pretreat, and densify biomass (via pellets) and thereby enable very large biorefineries using a decentralized system to collect these pellets. Such a corn‐stover based decentralized system using depots would establish one or two very large‐scale decentralized biorefineries capable of processing about 8–12% of the total corn stover available in the US Midwest. These decentralized biorefineries are economically competitive with the centralized biorefineries. About 55–153 depots could supply the pretreated pellets to the individual decentralized biorefineries leading to an annual production of 1.02–2.91 billion liters of cellulosic ethanol fuel. Most of the participating depots are located in Illinois and Iowa. The total EISA‐compliant ethanol fuel produced in the decentralized system is 2.82–4.07 billion liters per year. The ethanol selling price in the depot‐based decentralized biorefinery system varies between US$0.67 and US$0.72 L−1. The greenhouse gas (GHG) savings from cellulosic ethanol in the decentralized system compared to gasoline are 3.35–4.84 Tg CO2 year−1. Importantly, the total capital investment per annual volume of ethanol in the decentralized biorefinery ranges from US$0.71 L1 to US$1.15 L1, while the total capital investment per annual ethanol volume in the centralized biorefinery is US$1.98 L−1. © 2018 Society of Chemical Industry and John Wiley & Sons, Ltd
Development and validation of a high‐throughput assay for the quantification of multiple green tea‐derived catechins in human plasma
Authors: Mawson Deborah H. , Jeffrey Keon L. , Teale Philip , Grace Philip B. 
Published: June 2018

AbstractA rapid, accurate and robust method for the determination of catechin (C), epicatechin (EC), gallocatechin (GC), epigallocatechin (EGC), catechin gallate (Cg), epicatechin gallate (ECg), gallocatechin gallate (GCg) and epigallocatechin gallate (EGCg) concentrations in human plasma has been developed. The method utilizes protein precipitation following enzyme hydrolysis, with chromatographic separation and detection using reversed‐phase liquid chromatography–tandem mass spectrometry (LC–MS/MS). Traditional issues such as lengthy chromatographic runtimes, sample and extract stability, and lack of suitable internal standards have been addressed. The method has been evaluated using a comprehensive validation procedure, confirming linearity over appropriate concentration ranges, and inter/intra‐batch precision and accuracies within suitable thresholds (precisions within 13.8% and accuracies within 12.4%). Recoveries of analytes were found to be consistent between different matrix samples, compensated for using suitable internal markers and within the performance of the instrumentation used. Similarly, chromatographic interferences have been corrected using the internal markers selected. Stability of all analytes in matrix is demonstrated over 32 days and throughout extraction conditions. This method is suitable for high‐throughput sample analysis studies.
Carboxylesterase and UDP‐glucuronosyltransferases mediated metabolism of irinotecan: In vitro and in vivo insights from quantitative ultra‐performance liquid chromatography–mass spectrometry analysis
Authors: Qin Yifeng , Kang An , Zhou Guisheng , Wang Huan , Wei Wei , Cao Yujie , Chen Yanyan , Wang Jing , Shi Yajun , Tang Yuping , Jiang Jianqin 
Published: June 2018

AbstractCarboxylesterase and UDP‐glucuronosyltransferase‐mediated metabolism of irinotecan (CPT‐11) has long been proposed to be responsible for its anti‐tumor activity and toxicity, like delayed‐onset diarrhea. However, recent studies failed to gain more comprehensive in vivo and in vitro pharmacokinetic profiles of irinotecan. Herein, we use rat plasma, human liver microsomes and immortalized HepG2 cell as experimental subjects to describe a sensitive and versatile UHPLC–MS/MS method for simultaneously quantifying CPT‐11 and its metabolites, including SN‐38 and SN‐38G. The method was applied to investigate the pharmacokinetic and metabolic behavior of CPT‐11 in the biological samples. Calibration curves for all bio‐matrices showed acceptable linearity (r2 > 0.99). The intra‐ and inter‐day precisions (RSD, %) were within 15% and the excellent accuracy (RE) was between 2.96 and 14.12%. In addition, the specificity, matrix effect and extraction recovery all met the requirements of biological sample analysis. We successfully applied this method to investigate the pharmacokinetics of irinotecan in various biological samples, mediated by carboxylesterase and UDP‐glucuronosyltransferase. This method could be employed in monitoring the metabolic status and clinical efficacy of irinotecan in the future.
Anti‐apoptotic effects of adipose‐derived adherent stromal cells in mesenchymal stem cells exposed to oxidative stress
Authors: Shin Sunhye , Choi Jung‐Won , Lim Soyeon , Lee Seahyoung , Jun Eun‐Young , Sun Hyun‐Min , Kim Il‐Kwon , Lee Hoon‐Bum , Kim Sang Woo , Hwang Ki‐Chul 
Published: June 2018

Adipose‐derived stromal vascular fractions (SVFs) are a heterogeneous collection of cells, and their regenerative modality has been applied in various animal experiments and clinical trials. Despite the attractive advantages of SVFs in clinical interventions, the recent status of clinical studies involving the application of SVFs in many diseases has not been fully evaluated. Mesenchymal stem cells (MSCs) are multipotent stromal cells that can differentiate into a variety of cell types despite their low numbers in heart tissue. Here, we sought to determine if SVF implantation into impaired heart tissue affected endogenous MSCs in the heart. Therefore, we investigated the expression levels of proteins associated with oxidation, inflammation, and apoptosis in MSCs co‐cultured with adipose‐derived adherent stromal cells (ADASs) from 6 donors' SVFs under oxidative stress conditions for their roles in many physiological processes in the heart. Interestingly, p53 pathway proteins and mitogen‐activated protein kinase (MAPK) signalling pathway components were up‐regulated by H2O2 but exhibited a downward trend in MSCs co‐cultured with ADASs. These data suggest that ADASs may inhibit oxidative stress‐induced apoptosis in MSCs via the p53 and MAPK pathways. Our findings also suggest that the positive effects of SVF implantation into damaged heart tissue may be attributed to the various responses of MSCs. This finding may provide new insights for the clinical application of adipose‐derived SVF transplantation in cardiac diseases.Significance of the studyWe investigated the expression levels of proteins associated with oxidation, inflammation, and apoptosis in MSCs co‐cultured with isolated ADASs from 6 donors' SVFs under oxidative stress conditions. Our results imply that isolated ADASs from SVFs may inhibit oxidative stress‐induced cell cycle arrest and/or apoptosis in MSCs via a p53‐dependent pathway. Furthermore, we identified an anti‐apoptotic mechanism involving oxidative stress‐induced apoptosis by adipose‐derived ADASs in MSCs for the first time. Our findings suggest that the positive effects of SVF implantation into damaged heart tissue may be attributed to the various actions of MSCs.
Effect of breadmaking process on mycotoxin content in white and whole wheat breads
Authors: Tibola Casiane Salete , de Miranda Martha Zavariz , Paiva Flávia Fernandes , Fernandes José Mauricio Cunha , Guarienti Eliana Maria , Nicolau Marcio 
Published: June 2018

AbstractBackground and objectivesFusarium graminearum may reduce the wheat flour yield, technological quality, and breadmaking performance. The objective was to evaluate the effect of breadmaking on the mycotoxin content in white and whole wheat breads to obtain information about the safety of wheat products. The wheat samples were contaminated via the addition of Fusarium‐damaged kernels to produce different levels of deoxynivalenol (DON), ranging from <500 to >5,000 μg/kg.FindingsBecause of the breadmaking process, a significant reduction in the DON concentration was observed in both the white and whole wheat breads at the upper DON levels (>2,000 μg/kg) compared with the flours. The DON reduction was 49% and 39%, respectively, in whole and white breads, compared with the original flours. ZON was only detected in the two higher levels of DON in the whole wheat flour (mean 33.1 μg/kg) and in the two whole wheat breads (mean 42.4 μg/kg).ConclusionsThe breadmaking process can be a complementary strategy to reduce the mycotoxin content in wheat products.Significance and noveltyThese results are important for wheat supply chain to meet the legislation requirements and to produce safer foods.