bluuebunny/crossref_metadata_2025_split huggingface dataset:
Racemization of Secondary‐Amine‐Containing Natural Products Using Heterogeneous Metal Catalysts
Authors: Kovács Barbara , Savela Risto , Honkala Karoliina , Murzin Dmitry Yu. , Forró Enikő , Fülöp Ferenc , Leino Reko 
Published: March 2018

AbstractHeterogeneously catalyzed racemization reactions of the secondary amines (S)‐1‐methyl‐6,7‐dimethoxy‐1,2,3,4‐tetrahydroisoquinoline (salsolidine) and (S)‐1‐methyl‐1,2,3,4‐tetrahydro‐ß‐carboline were investigated using Pd, Pt, and Ir on carbon or Al2O3 supports. A comparison of kinetics and deactivation on selected platinum and iridium catalysts was performed. Furthermore, the relative stabilities of (S)‐salsolidine and the corresponding imine on Pt(1 1 1) and Ir(1 1 1) surfaces were analyzed by density functional theory calculations. The racemization was faster on platinum and took place without detectable byproduct formation. Iridium, however, proved reusable and, in contrast to the platinum catalyst, deactivation at low catalyst concentration was not observed. Also, the physisorption of (S)‐salsolidine and the imine was stronger on platinum than on iridium.
Soft Template‐Directed Reactions: One‐Pot Synthetic Route for Bimetallic Core–Satellite–Shell Structured Electrocatalytic Nanospheres
Authors: He Yue , Wang Qin , Wei Zhen , Xu Ling , Wang Zenglin , Huang Hao , Jiao Huan 
Published: March 2018

AbstractA one‐pot synthesis strategy, which retards nanoparticle (NP) agglomeration in the initiation of reaction and prevents the combination of the core and small species, is reported. In the present study, we synthesize bimetallic core–shell structures of single Au cores and satellites‐like Pt NPs. The core was generated by using HAuCl4; thus, providing the unique conductive ability for electrons. The entire evolution process of Pt NPs during the whole reaction was confined within the SiO2 nanospheres. Through strong electrostatic attraction, the Pt NPs in a tight H3O+ packing accordingly increased the adsorbed hydrogen (Had) rate. The comparative investigation of electrocatalytic activities of the products and commercial Pt/C‐20 % in the hydrogen evolution reaction (HER) revealed that the Au@SiO2‐Pt, with a strong metal interaction effect in the electrolyte, exhibits a low Tafel slope of 52 mV dec−1, with its catalytic activity being maintained for at least 10 h. Impressively, it also demonstrates a high turnover frequency (TOF) value of 0.11 s−1.
Selective Glucose‐to‐Fructose Isomerization over Modified Zirconium UiO‐66 in Alcohol Media
Authors: de Mello Matheus Dorneles , Tsapatsis Michael 
Published: March 2018

AbstractModulated zirconium metal–organic framework UiO‐66 is shown to catalyze the isomerization of d‐glucose to d‐fructose in alcohol media. Fructose selectivity can change depending on solvent choice. We hypothesize that the difference in selectivity is related to a combined effect of adsorption and solvation effects, which may lead to the high formation of alkylglucosides in depletion of fructose if methanol or ethanol are used. A fructose selectivity of 72 % at 82 % glucose conversion in 1‐PrOH was achieved. The reaction mechanism was investigated using nuclear magnetic resonance spectroscopy. We demonstrate that UiO‐66 isomerizes glucose to fructose through an intramolecular C2–C1 hydride transfer. In addition, we show that modulated UiO‐66 is a highly active and stable catalyst at the reaction conditions, showing great potential for other sugar reactions.
Preparation of γ‐Fe2O3 Catalysts and their deNOx Performance: Effects of Precipitation Conditions
Authors: Wang Dong , Yang Qilei , Li Xiansheng , Peng Yue , Li Bing , Si Wenzhe , Lu Chunmei , Gan Lina 
Published: March 2018

AbstractMagnetic γ‐Fe2O3 catalysts were prepared by microwave‐assisted coprecipitation utilizing the direct‐titrate and back‐titrate precipitation technique with different precipitants, namely, (NH4)2CO3, NaOH, Na2CO3, and NH4OH, which were evaluated in the selective catalytic reduction of NOx with NH3. The optimum γ‐Fe2O3 catalyst preparation method was direct titration with NH4OH as the precipitant, which exhibits high deNOx efficiency. This direct titration was effective to maintain the proper crystallization degree of γ‐Fe2O3, improve the pore structure, and suppress the formation of α‐Fe2O3 phase, being advantageous to get tiny and uniform discrete γ‐Fe2O3 particles with high activity in selective catalytic reduction. NH4+‐based precipitants in direct titration leads to an increase of the surface O/Fe atom ratio, and more lattice oxygen sites are exposed to the crystal surface.
Modification of a Mercury Electrode with Different Thioalkanes: Structure‐Sensitive Bovine Serum Albumin Analysis
Authors: Ostatná Veronika , Černocká Hana , Hasoň Stanislav , Paleček Emil 
Published: March 2018

AbstractChronopotentiometric stripping (CPS) in combination with mercury electrodes is convenient for structure‐sensitive protein analysis. By using this method, we tested the discrimination between native and denatured bovine serum albumin (BSA) at various alkanethiol self‐assembled monolayers (SAMs). Our results showed that alkanethiol SAMs with different headgroups or different chain lengths had different influences on the efficiency of CPS in protecting BSA from the electric field‐induced denaturation. SAMs with longer alkanethiol chain lengths were more efficient in protecting BSA from denaturation at negatively charged electrode surface than those formed by short‐chain alkanethiols. Short alkanethiol SAMs could be prepared by co‐adsorption with the protein on the electrode surface, which was not possible with the long‐chain alkanethiols. CPS data were supported by impedance analysis. We believe that our work will be useful in the electrochemical sensing of nucleic acid‐protein and protein‐protein binding.
Template‐Free Synthesis of Hierarchical SSZ‐13 Microspheres with High MTO Catalytic Activity
Authors: Bing Liancheng , Tian Aixiu , Wang Fang , Yi Kaifeng , Sun Xingyuan , Wang Guangjian 
Published: March 2018

AbstractHierarchical SSZ‐13 microspheres, with abundant mesoporous channels, have been successfully synthesized by addition of calcined SSZ‐13 crystals in the starting gel in the absence of any organic templates. This strategy not only remarkably reduces the production cost and environmental pollution, but also significantly decreases the crystallization time as well as evidently reducing the zeolite crystal sizes in many cases. The synthesized sample was characterized by XRD, BET, ICP, SEM, TEM, TG, and NH3‐TPD, which indicates that the organic template free synthesized SSZ‐13 exhibits high crystallinity, textural properties, and acidity. Moreover, the synthesized hierarchical SSZ‐13 catalyst shows outstanding performance in the methanol‐to‐olefin (MTO) reaction, with slightly higher ethylene plus propylene selectivity and prolonged catalyst lifetime as compared to the templated SSZ‐13 catalyst.
2D and 3D Coordination Networks of Polynuclear Bismuth Oxido/Hydroxido Sulfonato Clusters from Low Temperature Solid‐State Metathesis Reactions
Authors: Senevirathna Dimuthu C. , Werrett Melissa V. , Blair Victoria L. , Mehring Michael , Andrews Philip C. 
Published: March 2018

AbstractSolid‐state metathesis (SSM) reactions between Bi(NO3)3⋅5 H2O and potassium benzene‐1,2‐disulfonate (=1,2‐BDSK2), sodium benzene‐1,3‐disulfonate (=1,3‐BDSNa2) allows access to the first 2D, {[Bi6O4(OH)4(1–2BDS)2(NO3)2⋅4 H2O]⋅11 H2O}∞ and {[Bi22O24(OH)6(1,3‐BDS)6⋅12 DMSO]⋅3 DMSO⋅4 H2O}∞, and 3D, {[Bi6O4(OH)4(1,3‐BDS)3⋅4 H2O]⋅6 H2O}∞, polymeric networks of sulfonato encapsulated polynuclear bismuth oxido/hydroxido clusters.
Cyclic Seleninate Esters, Spirodioxyselenuranes and Related Compounds: New Classes of Biological Antioxidants That Emulate Glutathione Peroxidase
Authors: Sands Kai N. , Tuck Tyler A. , Back Thomas G. 
Published: March 2018

AbstractSelenium compounds play an important role in redox homeostasis in living organisms. One of their major functions is to suppress the harmful effects of hydrogen peroxide, hydroperoxides and downstream reactive oxygen species that lead to oxidative stress, which has in turn been implicated in many diseases and degenerative conditions. The glutathione peroxidase (GPx) family of selenoenzymes plays a key protective role by catalyzing the reduction of peroxides with glutathione. Considerable effort has been expended toward the discovery of small‐molecule selenium compounds that mimic GPx. To date, ebselen has been the most widely studied such compound, including in several clinical trials. However, despite its proven lack of significant toxicity, it displays only moderate catalytic activity and very poor aqueous solubility. The cyclic seleninate esters and spirodioxyselenuranes have recently been investigated as potential next generation GPx mimetics, along with structurally related selenenate esters, diazaselenuranes and pincer selenuranes. Their catalytic activities, redox mechanisms and structure–activity relationships are described in this Review, along with a description and discussion of the relative merits of assays for measuring their activities.
Gold(I)‐Catalysed Hydroarylation of 1,3‐Disubstituted Allenes with Efficient Axial‐to‐Point Chirality Transfer
Authors: Sutherland Daniel R. , Kinsman Luke , Angiolini Stuart M. , Rosair Georgina M. , Lee Ai‐Lan 
Published: March 2018

AbstractHydroarylation of enantioenriched 1,3‐disubstituted allenes has the potential to proceed with axial‐to‐point chirality transfer to yield enantioenriched allylated (hetero)aryl compounds. However, the gold‐catalysed intermolecular reaction was previously reported to occur with no chirality transfer owing to competing allene racemisation. Herein, we describe the development of the first intermolecular hydroarylations of allenes to proceed with efficient chirality transfer and summarise some of the key criteria for achieving high regio‐ and stereoselectivity.
Recent Trends in Metallopolymer Design: Redox‐Controlled Surfaces, Porous Membranes, and Switchable Optical Materials Using Ferrocene‐Containing Polymers
Authors: Gallei Markus , Rüttiger Christian 
Published: March 2018

AbstractMetallopolymers with metal functionalities are a unique class of functional materials. Their redox‐mediated optoelectronic and catalytic switching capabilities, their outstanding structure formation and separation capabilities have been reported recently. Within this Minireview, the scope and limitations of intriguing ferrocene‐containing systems will be discussed. In the first section recent advances in metallopolymer design will be given leading to a plethora of novel metallopolymer architectures. Discussed synthetic pathways comprise controlled and living polymerization protocols as well as surface immobilization strategies. In the following sections, we focus on recent advances and new applications for side‐chain and main‐chain ferrocene‐containing polymers as (i) remote‐switchable materials, (ii) smart surfaces, (iii) redox‐responsive membranes, and some recent trends in (iv) photonic structures and (v) other optical applications.
Synthesis, Structures, and Optical Properties of Azahelicene Derivatives and Unexpected Formation of Azahepta[8]circulenes
Authors: Chen Fengkun , Tanaka Takayuki , Mori Tadashi , Osuka Atsuhiro 
Published: March 2018

AbstractPolycyclic heteroaromatic compounds including pyrrole units are promising functional scaffolds owing to their electron‐rich nature, bright fluorescence, and applicability to anion recognition at the pyrrolic hydrogen atom. We report herein the effective synthesis of pseudo‐aza[5]helicene and aza[7]helicene derivatives, and unexpected formation of azahepta[8]circulenes by oxidative fusion reactions. By choosing reaction conditions and peripheral substituents attached at the terminal indole moieties, we obtained aza[7]helicenes 10 a–c and azahepta[8]circulenes 11 a,c selectively in moderate to good yields. Their solid‐state structures have been revealed by X‐ray diffraction analysis. UV/Vis absorption, emission, and cyclic voltammetry of these compounds were studied in comparison with those of previously reported tetraaza[8]circulene (TA8C), a symmetric and planar molecule. Furthermore, the enantiomeric separation of dimethyl‐substituted aza[7]helicene 10 b was achieved, and the racemization kinetics have been elucidated both theoretically and experimentally. This work illustrates a wealth of advantages of pyrrole incorporation into the polycyclic aromatic scaffolds in terms of synthetic aspects, structural variation, and optical tuning.
Computational Screening of New Orthogonal Metal‐Free Dipolar Cycloadditions of Mesomeric Betaines
Authors: de la Concepción Juan García , Ávalos Martín , Cintas Pedro , Jiménez José Luis 
Published: March 2018

AbstractComputational strategies have gained increasing impact in the de novo design of large molecular sets targeted to a desired application. Herein, DFT‐assisted theoretical analyses of cycloadditions, involving mesoionic dipoles and strained cycloalkynes, unveil a series of unexplored mesomeric betaines as vastly superior candidates for orthogonal applications. Thus, isosydnones; thiosydnones; and a six‐membered homolog, 6‐oxo‐1,3‐oxazinium‐4‐olate, exhibit enhanced reactivity with respect to sydnone, which is the archetypal mesoionic ring employed so far in orthogonal chemistry. These compounds were found by assessing energy barriers and transition structures, which are largely governed by electron fluxes from dipolarophile to dipole and noncovalent interactions. Charge‐transfer analysis also accounts for previous experimental and theoretical results gathered in the literature, and provides a rationale for further substitution variations. The above naked dipoles release only CO2 as a byproduct through retro‐Diels–Alder of the resulting cycloadducts. These results should invite practitioners to look at such underestimated dipoles and could also help to minimize the number of experiments.
Assembly of Tetrahydropyran Derivatives from Aldehydes, Allylboronates, and Syngas by Asymmetric Relay Catalytic Cascade Reaction
Authors: Li Lu‐Lu , Su Yong‐Liang , Han Zhi‐Yong , Gong Liu‐Zhu 
Published: March 2018

AbstractAn efficient synthesis of highly enantio‐enriched tetrahydropyrans from readily available aldehydes, allylboronates, and syngas has been established by multiply relay catalysis of rhodium and chiral phosphoric acid. The cascade reaction integrates the asymmetric allylboration of aldehydes and alkene hydroformylation, providing a structurally diverse range of products with different workup procedures. The concise synthesis of key chiral building blocks to access herboxidiene and leucascandrolide A demonstrates the high synthetic utility of this method. The cascade reaction employing alkenes to replace aldehydes was also successful.
Catalytic C−C Bond Formation Using a Simple Nickel Precatalyst System: Base‐ and Activator‐Free Direct C‐Allylation by Alcohols and Amines
Authors: Sweeney Joseph B. , Ball Anthony K. , Smith Luke J. 
Published: March 2018

AbstractA “totally catalytic” nickel(0)‐mediated method for base‐free direct alkylation of allyl alcohols and allyl amines is reported. The reaction is selective for monoallylation, uses an inexpensive NiII precatalyst system, and requires no activating reagents to be present.
Effects of hydrothermal dewatering of lignite on rheology of coal water slurry
Authors: Li Qiang , Yang Dingzheng , Liu Qingxia , Zhang Jiansheng 
Published: March 2018

AbstractMaximizing the dry‐based solid loading of coal particles in water is essential in increasing the burning efficiency of coal water slurry, which has been widely used as a liquid fuel. Understanding the rheology of coal water slurry could provide fundamental guidance on designing and optimizing coal water slurry formulation. The rheological studies have shown that coal water slurries made with lignite samples after hydrothermal dewatering (HTD) exhibit a stronger shear thinning behaviour as compared with those made with raw lignite samples. The viscosity of coal water slurry at the shear rate of 100 s−1 decreases with an increasing HTD temperature, which is probably due to the decrease of volume of lignite particles caused by the permanent reduction of both bound and non‐freezable water (inherent moisture) after the HTD process. The reduction of the inherent moisture of lignite samples after HTD treatment was elucidated by differential scanning calorimetry (DSC) under the temperature well below the freezing point. A lignite water slurry with a solid loading of 62 wt% db (dry basis) is obtained after hydrothermal dewatering at 300 °C with the addition of 1.2 wt% of polycarboxylate ether (PCE). Our findings indicated that hydrothermal dewatering of lignite has profound impacts on the inherent moisture of lignite and the rheological properties of coal water slurry.
Dithionated Nucleobases as Effective Photodynamic Agents against Human Epidermoid Carcinoma Cells
Authors: Pollum Marvin , Lam Minh , Jockusch Steffen , Crespo‐Hernández Carlos E. 
Published: March 2018

AbstractSulfur‐substituted nucleobases (i.e., thiobases) are a prospective class of compounds for clinical and cosmetic topical phototherapies. Recent investigations of several thiobases have revealed the ultrafast and efficient population of reactive triplet states upon ultraviolet‐A (UVA) irradiation and the subsequent generation of singlet oxygen in high yield. In this contribution, we examine the photosensitizing activities of three of the most promising thiobase derivatives discovered to date: 2,4‐dithiothymine, 2,4‐dithiouracil, and 2,6‐dithiopurine. These derivatives are shown to decrease the proliferation of human epidermoid carcinoma cells by up to 63 % in vitro, only upon activation with a low dose of UVA radiation (5 J cm−2). The generation of reactive oxygen species plays a minor role in the mode of action, suggesting these dithiobases may be effective within oxygen‐deficient environments. Importantly, the photosensitized activity correlates with the magnitude of the triplet lifetime, which should guide the molecular design of next‐generation photodynamic agents.
Efficacy and safety results of depatuxizumab mafodotin (ABT‐414) in patients with advanced solid tumors likely to overexpress epidermal growth factor receptor
Authors: Goss Glenwood D. , Vokes Everett E. , Gordon Michael S. , Gandhi Leena , Papadopoulos Kyriakos P. , Rasco Drew W. , Fischer JuDee S. , Chu Katharine L. , Ames William W. , Mittapalli Rajendar K. , Lee Ho‐Jin , Zeng Jiewei , Roberts‐Rapp Lisa A. , Loberg Lise I. , Ansell Peter J. , Reilly Edward B. , Ocampo Christopher J. , Holen Kyle D. , Tolcher Anthony W. 
Published: March 2018

BACKGROUNDEpidermal growth factor receptor (EGFR) alterations are associated with multiple cancers. Current EGFR‐directed therapies have led to increased efficacy but are associated with specific side effects. The antibody‐drug conjugate depatuxizumab mafodotin (depatux‐m) targets EGFR with a monoclonal antibody linked to a cytotoxin, and is highly tumor‐specific.METHODSThis phase 1/2 study evaluated the safety, pharmacokinetics, and efficacy of depatux‐m in patients who had advanced solid tumors with known wild‐type EGFR overexpression, amplification, or mutated EGFR variant III. A 3 + 3 dose escalation was used, and 2 dosing schedules were evaluated. Depatux‐m also was manufactured under an alternate process to reduce the drug load and improve the safety profile, and it was tested at the maximum tolerated dose (MTD). In another cohort, prolonged infusion time of depatux‐m was evaluated; and a cohort with confirmed EGFR amplification also was evaluated at the MTD.RESULTSFifty‐six patients were treated. The MTD and the recommended phase 2 dose for depatux‐m was 3.0 mg/kg. Common adverse events (AEs) were blurred vision (48%) and fatigue (41%). A majority of patients (66%) experienced 1 or more ocular AEs. Grade 3 or 4 AEs were observed in 43% of patients. One patient with EGFR‐amplified, triple‐negative breast cancer had a partial response. Stable disease was observed in 23% of patients. Pharmacokinetics revealed that depatux‐m exposures were approximately dose‐proportional.CONCLUSIONSDepatux‐m resulted in infrequent nonocular AEs but increased ocular AEs. Patient follow‐up confirmed that ocular AEs were reversible. Lowering the drug‐antibody ratio did not decrease the number of ocular AEs. A partial response in 1 patient with EGFR‐amplified disease provides the opportunity to study depatux‐m in diseases with a high incidence of EGFR amplification. Cancer 2018;124:2174‐83. © 2018 The Authors. Cancer published by Wiley Periodicals, Inc. on behalf of American Cancer Society. This is an open access article under the terms of the Creative Commons Attribution NonCommercial License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited and is not used for commercial purposes.
Pilot study of a multimodal intervention to enhance sexual function in survivors of hematopoietic stem cell transplantation
Authors: El‐Jawahri Areej , Fishman Sarah R. , Vanderklish Julie , Dizon Don S. , Pensak Nicole , Traeger Lara , Greer Joseph A. , Park Elyse R. , Markovitz Netana , Waldman Lauren , Hunnewell Chrisa , Saylor Meredith , Driscoll Jessica , Li Zhigang , Spitzer Thomas R. , McAfee Steven , Chen Yi‐Bin , Temel Jennifer S. 
Published: March 2018

BACKGROUNDAlthough sexual dysfunction is common after hematopoietic stem cell transplantation (HCT), interventions to address sexual function are lacking.METHODSWe conducted a pilot study to assess the feasibility and preliminary efficacy of a multimodal intervention to address sexual dysfunction in allogeneic HCT survivors. Transplant clinicians screened HCT survivors ≥3 months post‐HCT for sexual dysfunction causing distress. Those who screened positive attended monthly visits with a trained transplant clinician who: 1) performed an assessment of the causes of sexual dysfunction; 2) educated and empowered the patient to address his or her sexual concerns; and 3) implemented therapeutic interventions targeting the patient's needs. Feasibility was defined as having approximately 75% of patients who screened positive agreeing to participate and 80% attending at least 2 intervention visits. We administered the Patient‐Reported Outcomes Measurement Information System (PROMIS) sexual function and satisfaction measure, the Functional Assessment of Cancer Therapy–Bone Marrow Transplant (FACT‐BMT), and the Hospital Anxiety and Depression Scale (HADS) to evaluate sexual function, quality of life (QOL), and mood, respectively, at baseline and 6 months postintervention.RESULTSApproximately 33.1% of patients (50 of 151 patients) screened positive for sexual dysfunction causing distress and 94.0% (47 of 50 patients) agreed to participate, with 100% attending 2 intervention visits. Participants reported improvements in satisfaction (P<.0001) and interest in sex (P<.0001), as well as orgasm (P<.0001), erectile function (P<.0001), vaginal lubrication (P = .0001), and vaginal discomfort (P = .0005). At baseline, approximately 32.6% of participants were not sexually active, compared with 6.5% after the intervention (P = .0005). Participants reported improvement in their QOL (P<.0001), depression (P = .0002), and anxiety (P = .0019).CONCLUSIONSA multimodal intervention to address sexual dysfunction integrated within the transplant clinic is feasible with encouraging preliminary efficacy for improving sexual function, QOL, and mood in HCT survivors. Cancer 2018;124:2438‐46. © 2018 American Cancer Society.