bluuebunny/crossref_metadata_2025_split huggingface dataset:
Self‐Assembled GO Honeycomb Microarray for Selective Cancer Cell Capture and Single Cell Analysis of Proteolytic Expression
Authors: Chen Shuangshuang , Lu Qinghua 
Published: September 2020

AbstractProteolytic enzymes expressed by circulating tumor cells are proved to facilitate their invasion into multiple organs via cleaving natural ECM networks, leading to consequent metastasis colonization and malignant lethality. Recent evidence suggests the rare metastasis initiating cells with higher proteolytic levels among circulating tumor cells (CTCs) may strongly increase the risk of metastasis. Beyond selective CTC capture, the heterogeneity in proteases expression provides a promising indicator for metastasis happening. To this end, the graphene oxide (GO) honeycomb microarray with single CTC matched sizes is fabricated via the self‐assembly breath figure approach, which serves as an integrated protocol for selective CTC capture and single‐cell analysis of protease activity. Contributing to synergistic effects of structure and chemistry, CTCs can be efficiently isolated and individually trapped in each honeycomb hole. Meanwhile, the crosstalk among CTCs can be erased by blocking direct cell‐to‐cell contact, which offers promising potentials in the single‐cell analysis of protease expression. Integrating specific capture and in situ analysis of single CTCs on GO micropatterned surface is of significant importance in various biological and clinical applications such as cancer diagnostics and cancer therapeutic evaluation.
Phase Change Material‐Containing Mesoporous Zeolite Composite for Adsorption Heat Recovery
Authors: Choi Jihye , Valtchev Valentin , Moteki Takahiko , Ogura Masaru 
Published: September 2020

AbstractA mesoporous zeolite is proposed as a phase change material (PCM) carrier. Owing to its physicochemical properties, the PCM‐containing adsorbent has dual functions, namely simultaneous adsorption, and heat storage. In this study, the mesoporous chabazite‐type zeolite SSZ‐13, is prepared under various conditions to obtain optimized mesoporous SSZ‐13 (MSSZ‐13) as a PCM‐containing adsorbent. The PCM is then successfully introduced in the created mesopore space through vapor phase synthesis, and the micropores could be utilized as an adsorption field. The efficiency of the as‐prepared PCM‐containing MSSZ‐13 is evaluated by a dehumidification process. The afforded experimental results show suppressed bed temperature ramping, owing to the recovery of the heat generated upon H2O adsorption through the PCM. Moreover, the relative amount of adsorbed water increases at the initial period of time‐on‐stream of the contacting humid fluid.
Asymmetric Fluorination Reactions promoted by Chiral Hydrogen Bonding‐based Organocatalysts
Authors: Auria‐Luna Fernando , Mohammadi Somayeh , Divar Masoumeh , Gimeno M. Concepción , Herrera Raquel P. 
Published: September 2020

AbstractFluorinated compounds can exhibit interesting biological properties. The importance of these species has made that the chemistry of fluorine has experienced a great development. On this review, the recent advances on asymmetric fluorination reactions promoted by chiral hydrogen bonding‐based organocatalysts are discussed. Hence, examples using phosphoric acid, carboxylic acid, (thio)urea and squaramide derivatives are illustrated. The growth of this field is amazing. We have only considered pivotal works in which direct fluorination takes place using a fluorinating agent, leaving aside the reactions where a fluorine atom is incorporated from the beginning as part of other reactants. Herein, the scarce existing examples on this field of research have been compiled.magnified image
Nickel‐Catalyzed Direct Trifluoroethylation of Aryl Iodides with 1,1,1‐Trifluoro‐2‐Iodoethane via Reductive Coupling
Authors: Li Han , Sheng Jie , Liao Guang‐Xu , Wu Bing‐Bing , Ni Hui‐Qi , Li Yan , Wang Xi‐Sheng 
Published: September 2020

AbstractA nickel‐catalyzed direct trifluoroethylation of aryl iodides with an industrial raw material CF3CH2I has been developed, demonstrating high efficiency, excellent functional‐group compatibility, especially with large sterically hindered groups. The key to success is the combination of nickel with readily available nitrogen and phosphine ligands. The powerful potential of this strategy is further demonstrated by the late‐stage modification of several derived bioactive molecules.magnified image
Au–Manganese Oxide Nanostructures by a Plasma‐Assisted Process as Electrocatalysts for Oxygen Evolution: A Chemico‐Physical Investigation
Authors: Bigiani Lorenzo , Gasparotto Alberto , Andreu Teresa , Verbeeck Johan , Sada Cinzia , Modin Evgeny , Lebedev Oleg I. , Morante Juan Ramón , Barreca Davide , Maccato Chiara 
Published: September 2020

AbstractEarth‐abundant and eco‐friendly manganese oxides are promising platforms for the oxygen evolution reaction (OER) in water electrolysis. Herein, a versatile and potentially scalable route to gold‐decorated manganese oxide‐based OER electrocatalysts is reported. In particular, MnxOy (MnO2, Mn2O3) host matrices are grown on conductive glasses by plasma assisted‐chemical vapor deposition (PA‐CVD), and subsequently functionalized with gold nanoparticles (guest) as OER activators by radio frequency (RF)‐sputtering. The final selective obtainment of MnO2‐ or Mn2O3‐based systems is then enabled by annealing under oxidizing or inert atmosphere, respectively. A detailed material characterization evidences the formation of high‐purity MnxOy dendritic nanostructures with an open morphology and an efficient guest dispersion into the host matrices. The tailoring of MnxOy phase composition and host–guest interactions has a remarkable influence on OER activity yielding, for the best performing Au/Mn2O3 system, a current density of ≈5 mA cm−2 at 1.65 V versus the reversible hydrogen electrode (RHE) and an overpotential close to 300 mV at 1 mA cm−2. Such results, comparing favorably with literature data on manganese oxide‐based materials, highlight the importance of compositional control, as well as of surface and interface engineering, to develop low‐cost and efficient anode nanocatalysts for water splitting applications.
Transfer Learning as Tool to Enhance Predictions of Molecular Properties Based on 2D Projections
Authors: Lentelink Niklas Julian , Palkovits Stefan 
Published: September 2020

AbstractImages of molecules are widely used to predict molecule properties in teaching and chemical research. A trained chemist can easily derive molecule properties by analyzing its structure and evaluate its functional groups. To predict, for example, the water solubility of an organic compound a chemist would intuitively count the number of polar groups, consider the size of the molecule, and estimate the water/molecule interaction by counting the number of H‐bond donors and acceptors. Therefore, 2D molecule representations and their directly accessible features should provide enough information to predict the molecule's structure‐dependent properties. To support this thesis, different image‐based machine learning approaches as dense neural networks, convolutional neural networks, clustering, data augmentation, and transfer learning are compared and evaluated in this work. The influence of the image size as well as the network size is discussed. Finally, a simple yet effective dense neural network trained on expert preselected, visually accessible features, is presented and its efficiency and comparability to other more complex methods are demonstrated.
Sugarcane response to polyhalite fertilizer in Brazilian Oxisols
Authors: Pavinato Paulo Sergio , Corá José Eduardo , de Camargo Santos Aline , Herrera Wilfrand Ferney Bejarano , Pavuluri Kiran , Pierce Francis J. 
Published: September 2020

AbstractPolyhalite (PYH), (K2SO4·MgSO4·2CaSO4·2H2O), contains four nutrients of great importance to sugarcane (Saccharum spp.), but has lower water solubility than traditional K fertilizers. Two studies were conducted to determine if PYH fertilizer (11.6% K) promoted sugarcane response comparable to other K fertilizers on highly weathered, acidic Oxisol soils in Brazil. A pot study compared PYH with potassium chloride (KCl, 50% K) and potassium sulfate (K2SO4, 40% K and 17% S), both amended to the same Ca, Mg, and S contents, applied at five rates ranging from 0 to 166 kg K ha−1in limed and unlimed soil. A field study evaluated PYH with KCl applied in a 5–30–10 blend at planting followed by sidedress applications of K as PYH or KCl in the establishment year and two ratoon crops. In the pot study, there were minimal effects of fertilizer source and application rate on early growth in sugarcane while liming was detrimental. Uptake of K in the biomass was linear and similar among fertilizer sources. PYH increased S uptake and soil tests compared to KCl and K2SO4. In the field study, KCl and PYH had similar sugarcane yield and quality with K uptake in both exceeding K applied and PYH increased S uptake and soil test SO4–S. These studies confirm nutrient release from PYH to sugarcane was adequate and comparable to KCl and K2SO4, with some effect of PYH on nutrient uptake and soil test that did not affect sugarcane yield or quality.
Exploring the optimal sampling density to characterize spatial heterogeneity of soil carbon stocks in a Karst Region
Authors: Zhang zhenming , Zhou Yunchao , Huang Xianfei 
Published: September 2020

AbstractThe aim of this study is to investigate the spatial distribution of soil organic C stock and to determine the optimal number of samples required for its determination, in a small karst basin. By taking the soil organic C stock in the Houzhai River Basin, calculated on the basis of a 150 by 150 m grid sampling design as original data and selecting sample sets at five grid scales (300, 450, 600, 750, and 900 m), the optimal number of samples for different sampling distances was obtained, using geographic information system (GIS) technology and geostatistical analyses. With increasing sampling distance, the coefficient of variation of the soil organic C stocks first increased and then decreased; the spatial predictions of the soil organic C stock tended to be smoother, and the ability to represent detail was weaker. The prediction accuracy was comprehensively discussed. When the surface soil organic C stock (0–20 cm) was considered, 357 sampling points at a sampling distance of 450 by 450 m could accurately represent its spatial variability. For a depth of 0–100 cm, 200 sampling points and a sampling distance of 600 m could accurately represent the spatial variability in the soil organic C stock. The results of this study could provide data for future studies for the estimation of soil organic C stock in the karst areas of Southwest China and similar areas.
Diamine versus amines blend for CO2 chemical absorption
Authors: Gómez‐Díaz Diego , Muñiz‐Mouro Abel , Navaza José M. , Rumbo Antonio 
Published: September 2020

AbstractPresent work analyses the behavior of aqueous solutions of N,N‐dimethylethylenediamine as chemical solvent for carbon dioxide separation by gas–liquid absorption. The interest of this molecule is centered on the presence of different types of amino centers that confer it the capability to act as a solvent based on amines blend. For this reason, a comparison between diamine and amines blend solvent has been carried out in order to understand the differences between these solvents using absorption and nuclear magnetic resonance studies. This experimental work analyses the influence of amine type, concentration, and ratio between different amines. Also, the effect of gas flow rate used in the bubble column reactor upon the absorption kinetics has been analyzed.
Niche similarity in diploid‐autotetraploid contact zones ofArabidopsis arenosaacross spatial scales
Authors: Morgan Emma J. , Čertner Martin , Lučanová Magdalena , Kubíková Kateřina , Marhold Karol , Kolář Filip 
Published: September 2020

PremiseWhole genome duplication is a major evolutionary event, but its role in ecological divergence remains equivocal. When populations of different ploidy (cytotypes) overlap in space, “contact zones” are formed, allowing the study of evolutionary mechanisms contributing toward ploidy divergence. Multiple contact zones per species’ range are often described but rarely leveraged as natural replicates. We explored whether the strength of niche differentiation of diploid and autotetraploidArabidopsis arenosavaries over distinct contact zones and if the frequency of triploids decreases from seedling to adult stage.MethodsWe characterized ploidy composition and habitat preferences in 264 populations across three contact zones using climatic niche modeling. Ecological differences of cytotypes were also assessed using local vegetation surveys at 110 populations within two contact zones, and at the finer scale within five mixed‐ploidy sites. This was complemented by flow cytometry of seedlings.ResultsWe found no niche differences between diploid and tetraploid populations within contact zones for either climatic or local environmental variables. Comparisons of cytotypes within mixed‐ploidy sites found weak niche differences that were inconsistent in direction. Triploid individuals were virtually absent (0.14%) in the field, and they were at a similarly low frequency (0.2%) in ex situ germinated seedlings.ConclusionsThis study demonstrates the strength in investigating different spatial scales across several contact zones when addressing ecological niche differentiation between ploidies. The lack of consistent habitat differentiation of ploidies across the scales and locations supports the recently emerging picture that processes other than ecological differentiation may underlie ploidy coexistence in diploid‐autopolyploid systems.
Relationships between mental health and diet during pregnancy and birth outcomes in a lower‐middle income country: “Healthy mothers, healthy communities” study in Vanuatu
Authors: Therrien Ann‐Sophie , Buffa Giovanna , Roome Amanda B. , Standard Elizabeth , Pomer Alysa , Obed Jimmy , Taleo George , Tarivonda Len , Chan Chim W. , Kaneko Akira , Olszowy Kathryn M. , Dancause Kelsey N. 
Published: September 2020

AbstractPoor maternal mental health during pregnancy is associated with adverse birth outcomes, including lower birthweight and gestational age. However, few studies assess both mental health and diet, which might have interactive effects. Furthermore, most studies are in high‐income countries, though patterns might differ in low‐ and middle‐income countries (LMICs).ObjectivesTo analyze relationships between mental health and diet during pregnancy with birth outcomes in Vanuatu, a lower‐middle income country.MethodsWe assessed negative emotional symptoms of depression, anxiety, and stress (referred to as “distress”) and dietary diversity during pregnancy, and infant weight and gestational age at birth, among 187 women. We used multivariate linear regression to analyze independent and interactive relationships between distress, dietary diversity, and birth outcomes, controlling for sociodemographic and maternal health covariates.ResultsThere were no direct linear relationships between dietary diversity or distress with infant birthweight or gestational age, and no curvilinear relationships between distress and infant outcomes. We observed interactive relationships between distress and dietary diversity on birthweight, explaining 2.1% of unique variance (P = .024). High levels of distress predicted lower birthweights among women with low dietary diversity. These relationships were not evident among women with moderate or high dietary diversity.ConclusionsRelationships between mental health and diet might underlie inconsistencies in past studies of prenatal mental health and birthweight. Results highlight the importance of maternal mental health on birthweight in LMICs. Interactive relationships between mental health and diet might ultimately point to new intervention pathways to address the persistent problem of low birthweight in LMICs.
Palladium‐Catalyzed Direct C−H Arylation of Arenes Promoted by Quaternary Ammonium Salt
Authors: Yang Sabyuk , Hong Soon Hyeok 
Published: September 2020

AbstractA new Pd‐based catalytic system for the direct C−H arylation of arenes was developed. The use of a substoichiometric amount of quaternary ammonium salt as an additive with a Pd source achieved the direct arylation of unactivated arenes under milder reaction conditions in moderate to high yields. The ammonium salt generates the anionic palladium complex, thereby facilitating arylation by a concerted metalation‐deprotonation process.
Sequential One‐Pot Coupling Reactions of Diiodobenzenes, Propiolic Acid, and Aryl Halides for the Synthesis of Diarylalkynyl Arenes
Authors: Ryu Beomseok , Oh Jonghoon , Lee Sunwoo 
Published: September 2020

AbstractDiiodobenzenes were employed in palladium‐catalyzed one‐pot sequential reactions with propiolic acid and aryl halides to provide the corresponding diarylalkynyl benzenes. The combination of Pd(PPh3)4 (10 mol %) and DBU (5.0 equiv) gave optimal results in the sequence. Reactions with 1,2‐diiodobenzene gave higher yields than those utilizing 1,3‐ and 1,4‐diiodobenzenes. Furthermore, benzenes bearing electron‐donating substituents gave higher yields than those with electron‐withdrawing substituents.
Amidation Reaction of Quinoline‐3‐carboxylic Acids with Tetraalkylthiuram Disulfides under Simple Conditions: A facile Synthesis of Quinoline‐3‐carboxamides
Authors: Hu Jingyan , Ye Xiefeng , Hao Shuai , Zhao Qianrui , Zhao Mingqin , Wei Yuewei , Wu Zhiyong , Wang Na , Ji Xiaoming 
Published: September 2020

AbstractA highly efficient and simple procedure for the synthesis quinoline‐3‐carboxamides and their analogues via amidation reaction of quinoline‐3‐carboxylic acids with tetraalkylthiuram disulfides has been developed. The reaction proceeds efficiently under simple reaction conditions and features the generality of broad scope of substrates with good yields. This protocol provides a convenient procedure for the synthesis of various aza‐heteroaromatic carboxamides, which is of pharmaceutical interest.
Carbene‐Catalyzed Enantioselective Aldol Reaction: Post‐Aldol Stereochemistry Control and Formation of Quaternary Stereogenic Centers
Authors: Yang Xing , Majhi Pankaj Kumar , Chai Huifang , Liu Bin , Sun Jun , Liu Ting , Liu Yonggui , Zhou Liejin , Xu Jun , Liu Jiawei , Wang Dongdong , Zhao Yanli , Jin Zhichao , Chi Yonggui Robin 
Published: September 2020

AbstractThe dominated approaches for asymmetric aldol reactions have primarily focused on the aldol carbon–carbon bond‐forming events. Here we postulate and develop a new catalytic strategy that seeks to modulate the reaction thermodynamics and control the product enantioselectivities via post‐aldol processes. Specifically, an NHC catalyst is used to activate a masked enolate substrate (vinyl carbonate) to promote the aldol reaction in a non‐enantioselective manner. This reversible aldol event is subsequently followed by an enantioselective acylative kinetic resolution that is mediated by the same (chiral) NHC catalyst without introducing any additional substance. This post‐aldol process takes care of the enantioselectivity issues and drives the otherwise reversible aldol reaction toward a complete conversion. The acylated aldol products bearing quaternary/tetrasubstituted carbon stereogenic centers are formed in good yields and high optical purities.
CeIV‐ and HClO4‐Promoted Assembly of an Fe2IV(μ‐O)2 Diamond Core from its Monomeric FeIV=O Precursor at Room Temperature
Authors: Draksharapu Apparao , Xu Shuangning , Que Lawrence 
Published: September 2020

AbstractDiiron(IV)‐oxo species are proposed to effect the cleavage of strong C−H bonds by nonheme diiron enzymes such as soluble methane monooxygenase (sMMO) and fatty acid desaturases. However, synthetic mimics of such diiron(IV) oxidants are rare. Herein we report the reaction of (TPA*)FeII (1) (TPA*=tris(3,5‐dimethyl‐4‐methoxypyridyl‐2‐methyl)amine) in CH3CN with 4 equiv CAN and 200 equiv HClO4 at 20 °C to form a complex with an [FeIV2(μ‐O)2]4+ core. CAN and HClO4 play essential roles in this unprecedented transformation, in which the comproportionation of FeIII‐O‐CeIV and FeIV=O/Ce4+ species is proposed to be involved in the assembly of the [FeIV2(μ‐O)2]4+ core.
Highly Selective CO2 Electroreduction to CH4 by In Situ Generated Cu2O Single‐Type Sites on a Conductive MOF: Stabilizing Key Intermediates with Hydrogen Bonding
Authors: Yi Jun‐Dong , Xie Ruikuan , Xie Zai‐Lai , Chai Guo‐Liang , Liu Tian‐Fu , Chen Rui‐Ping , Huang Yuan‐Biao , Cao Rong 
Published: September 2020

AbstractIt is still a great challenge to achieve high selectivity of CH4 in CO2 electroreduction reactions (CO2RR) because of the similar reduction potentials of possible products and the sluggish kinetics for CO2 activation. Stabilizing key reaction intermediates by single type of active sites supported on porous conductive material is crucial to achieve high selectivity for single product such as CH4. Here, Cu2O(111) quantum dots with an average size of 3.5 nm are in situ synthesized on a porous conductive copper‐based metal–organic framework (CuHHTP), exhibiting high selectivity of 73 % towards CH4 with partial current density of 10.8 mA cm−2 at −1.4 V vs. RHE (reversible hydrogen electrode) in CO2RR. Operando infrared spectroscopy and DFT calculations reveal that the key intermediates (such as *CH2O and *OCH3) involved in the pathway of CH4 formation are stabilized by the single active Cu2O(111) and hydrogen bonding, thus generating CH4 instead of CO.
Radical Addition Enables 1,2‐Aryl Migration from a Vinyl‐Substituted All‐Carbon Quaternary Center
Authors: Li Zexian , Wang Minyan , Shi Zhuangzhi 
Published: September 2020

AbstractAn efficient method for photocatalytic perfluoroalkylation of vinyl‐substituted all‐carbon quaternary centers involving 1,2‐aryl migration has been developed. The rearrangement reactions use fac‐Ir(ppy)3, visible light and commercially available fluoroalkyl halides and can generate valuable multisubstituted perfluoroalkylated compounds in a single step that would be challenging to prepare by other methods. Mechanistically, the photoinduced alkyl radical addition to an alkene leads to the migration of a vicinal aryl substituent from its adjacent all‐carbon quaternary center with the concomitant generation of a C‐radical bearing two electron‐withdrawing groups that is further reduced by a hydrogen donor to complete the domino sequence.
A Room‐Temperature Stable Distonic Radical Cation
Authors: Chen Xiaodan , Liu Liu Leo , Liu Shihua , Grützmacher Hansjörg , Li Zhongshu 
Published: September 2020

AbstractDistonic radical cations (DRCs) with spatially separated charge and radical sites have, so far, largely been observed by gas‐phase mass spectrometry and/or matrix isolation spectroscopy work. Herein, we disclose the isolation of a crystalline dicarbondiphosphide‐based β‐distonic radical cation salt 3.+(BARF) (BARF=[B(3,5‐(CF3)2C6H3)4)]−) stable at room temperature and formed by a one‐electron‐oxidation‐induced intramolecular skeletal rearrangement reaction. Such a species has been validated by electron paramagnetic resonance (EPR) spectroscopy, single‐crystal X‐ray diffraction, UV/Vis spectroscopy and density functional theory (DFT) calculations. Compound 3.+(BARF) exhibits a large majority of spin density at a two‐coordinate phosphorus atom (0.74 a.u.) and a cationic charge located predominantly at the four‐coordinate phosphorus atom (1.53 a.u.), which are separated by one carbon atom. This species represents an isolable entity of a phosphorus radical cation that is the closest to a genuine phosphorus DRC to date.