bluuebunny/crossref_metadata_2025_split huggingface dataset:
Metal–Organic Frameworks: Host Photoreactive Properties
Authors: Richards Victoria J. , Reade Thomas J. , George Michael W. , Champness Neil R. 
Published: December 2014

Abstract
This chapter describes the development of photochemical applications of metal–organic frameworks (MOFs) with a particular emphasis on the use of photochemical reactions leading to structural modifications of functional groups within the framework structure. It also describes how a building‐block methodology can be used to introduce photoactive components as part of the framework. The chapter will show how photoactive MOFs can be prepared, whose properties with respect to guest inclusion can be modified for use as sensors. Examples of MOFs that include groups that undergo chemical reactions on photoirradiation, leading to either new chemical species or isomerization reaction, are discussed and the effect of the framework on the stabilization of unusual, reactive species is described. The influence of framework structure on photochemical processes is also discussed focusing on intraframework and interframework guest energy transfer and how such processes can be used to induce unusual photochemical and chemical reactions.
Metal‐Organic Frameworks: Metal‐Uptake
Authors: Hardie Michaele J. 
Published: December 2014

Abstract
Metal‐organic frameworks (MOFs) contain metal cations that are inherent to their framework structure and may also be intrinsic to material properties such as magnetism, catalysis, and luminescence. Uptake of additional metals by a MOF has the potential to introduce new functionality or to alter functionality and thus finds a variety of potential applications. For example, catalysis, luminescence or color changes for sensors, ion exchange, removal of metal contaminants from the atmosphere or solution, altering gas‐binding properties of a MOF by creation of electric dipoles on the framework surface, and ion transport for battery applications. Post‐synthetic modification (PSM) involves the solid‐state MOF framework being chemically altered. PSM of MOFs may occur such that additional or new heterometallic cations or metal‐containing moieties are taken up by the MOF. There are a number of mechanisms to effect metal uptake in MOFs. Direct grafting of metal cations onto the MOF frameworks can occur at pendant, unmetallated sites embedded within the framework linker ligand. For example, through pendant thiols or alcohol groups lining framework pores, or through unmetallated chelating or macrocyclic groups embedded in the framework. Organometallic fragments can be directly grafted onto the arene rings of MOF ligands. PSM of pendant organic functional groups can be used to either create a new ligand group for metal binding, or to directly tether a metal complex. Other mechanisms for forming pendant metal‐binding groups are to demetallation a nonstructural metal cation site, for example, within a linking metal‐salen ligand, or to use a ligand defect approach where ligands with additional binding sites are doped into the MOF during its synthesis. Ion exchange of counter‐anions within the pores of anionic MOFs is another method for metal uptake, and often involves the exchange of an organic counter‐cation for a metal. Metal‐containing guest molecules can be absorbed into the pores of MOFs through solution immersion or chemical vapor deposition techniques. Such complexes are often precursors to form metal@MOFs hydrid materials where metal nanoparticles are embedded in the pores. Exchange may also occur between structural components of a MOF, and metal cation metathesis, also referred to as transmetallation, is where metal cations within the framework are substituted for a different cation, usually with retention of the gross original framework structure.
Metal‐Organic Frameworks: Electrochemical Properties
Authors: Jaouen Frédéric , Morozan Adina 
Published: December 2014

AbstractMetal–organic frameworks (MOFs) with their open pore network; high density of coordinatively unsaturated metal ions; and extremely broad tunability of their pore size, functional groups, and metal‐ion coordination chemistry possess many of the assets required for a successful use in electrochemistry. Recent years have witnessed increased research efforts in this direction, with the vast majority of the literature discussed herein being published in 2010 or later. MOFs have been investigated for their ionic conductivity (especially proton conductivity), electrocatalytic properties, charge‐storage properties for electrochemical supercapacitors, or as rechargeable intercalation or conversion‐reaction electrode for batteries. A proton conductivity up to 2 S m−1has been reported for pure MOF systems (90% RH, 85 °C), up to 1 S m−1for MOFs impregnated with nonvolatile acids (0% RH, 200 °C), whereas a MOF‐polymer mixed‐matrix membrane has shown a conductivity of 25 S m−1(90% RH, 98 °C). In rechargeable batteries, MOF‐based negative electrodes have shown interesting initial capacities of 300 mAh g−1(Li‐intercalation) and 560 mAh g−1(conversion‐reaction mechanism). Positive electrodes based on Prussian blue (PB) analogs have shown a capacity up to 135 mAh g−1(alkali‐metal‐cation insertion), with high capacity retention at fast charging rate. Hybrids combining the well‐known positive electrode materials and PB analogs thus offer new possibilities to design electrodes. MOFs have also been successfully used as precursors to synthesize high‐surface‐area carbons, metal, or metal oxide nanostructured materials tested in electrochemical supercapacitors or rechargeable batteries, as well as nonprecious metal catalysts for the oxygen reduction reaction. In this sacrificial approach, MOFs are pyrolyzed in various atmospheres and the resulting materials do not contain any trace of MOF but present morphologies reminiscent of the pristine MOF structure, or characteristics that are otherwise difficult to reach.
Totalsynthese von Albicidin – eine Leitstruktur aus Xanthomonas albilineans für potente antibakterielle Gyrase‐Inhibitoren
Authors: Kretz Julian , Kerwat Dennis , Schubert Vivien , Grätz Stefan , Pesic Alexander , Semsary Siamak , Cociancich Stéphane , Royer Monique , Süssmuth Roderich D. 
Published: December 2014

AbstractDas Antibiotikum Albicidin wird von dem pflanzenpathogenen Bakterium Xanthomonas albilineans synthetisiert. Es zeigt eine bemerkenswerte Aktivität gegen Gram‐positive und Gram‐negative Mikroorganismen. Der Wildtypstamm wie auch der heterologe Expressionsstamm produziert Albicidin bislang in äußerst geringen Mengen, was die Untersuchung des biologischen Profils und die Ausarbeitung von Struktur‐Aktivitäts‐Beziehungen erschwert. Aus diesem Grund entwickelten wir eine konvergente Syntheseroute für Albicidin. Die unerwartet schwierige Knüpfung der Peptidbindungen zwischen aromatischen Aminosäuren konnte durch die Verwendung von Triphosgen als Kupplungsreagens ermöglicht werden. Die vorhergehende Strukturaufklärung und die außergewöhnliche antibakterielle Aktivität von Albicidin werden zudem durch die Totalsynthese bestätigt. Zudem ist es erstmals möglich, Albicidin im Multigramm‐Maßstab herzustellen, um das Potential einer kommerziellen Wirkstoffentwicklung eingehender zu untersuchen.
Toward the Design of a Catalytic Metallodrug: Selective Cleavage of G‐Quadruplex Telomeric DNA by an Anticancer Copper–Acridine–ATCUN Complex
Authors: Yu Zhen , Han Menglu , Cowan James A. 
Published: December 2014

AbstractTelomeric DNA represents a novel target for the development of anticancer drugs. By application of a catalytic metallodrug strategy, a copper–acridine–ATCUN complex (CuGGHK‐Acr) has been designed that targets G‐quadruplex telomeric DNA. Both fluorescence solution assays and gel sequencing demonstrate the CuGGHK‐Acr catalyst to selectively bind and cleave the G‐quadruplex telomere sequence. The cleavage pathway has been mapped by matrix assisted laser desorption ionization time‐of‐flight mass spectrometry (MALDI‐TOF MS) experiments. CuGGHK‐Acr promotes significant inhibition of cancer cell proliferation and shortening of telomere length. Both senescence and apoptosis are induced in the breast cancer cell line MCF7.
A Robust Microfluidic Device for the Synthesis and Crystal Growth of Organometallic Polymers with Highly Organized Structures
Authors: Liu Xiao , Yi Qiaolian , Han Yongzhen , Liang Zhenning , Shen Chaohua , Zhou Zhengyang , Sun Jun‐liang , Li Yizhi , Du Wenbin , Cao Rui 
Published: December 2014

AbstractA simple and robust microfluidic device was developed to synthesize organometallic polymers with highly organized structures. The device is compatible with organic solvents. Reactants are loaded into pairs of reservoirs connected by a 15 cm long microchannel prefilled with solvents, thus allowing long‐term counter diffusion for self‐assembly of organometallic polymers. The process can be monitored, and the resulting crystalline polymers are harvested without damage. The device was used to synthesize three insoluble silver acetylides as single crystals of X‐ray diffraction quality. Importantly, for the first time, the single‐crystal structure of silver phenylacetylide was determined. The reported approach may have wide applications, such as crystallization of membrane proteins, synthesis and crystal growth of organic, inorganic, and polymeric coordination compounds, whose single crystals cannot be obtained using traditional methods.
Biobased interpenetrating polymers networks derived from oligomerized soybean oil and polydimethylsiloxane
Authors: Dewasthale Sudhanwa , Graiver Daniel , Narayan Ramani 
Published: December 2014

ABSTRACTA series of interpenetrating polymer networks (IPNs) with different compositions were prepared from silylated oligomerized soybean oil and silanol‐terminated polydimethylsiloxane. Oligomerization of soybean oil was achieved by heating it with a catalyst in a Parr reactor at elevated temperatures. Vinyltrimethoxysilane was then grafted onto the oligomerized oil. Crosslinked films were obtained from solutions as the silanol groups between the two immiscible components condensed to form stable siloxanes linkages resulting in an entangled network characterized by microphase separation typical to IPNs. The crosslink density between the dispersed phase and the continuous phase was calculated from the average particle size of the dispersed phase. The mechanical and thermal properties were also studied and were found to be directly related to the composition and the crosslink density. These IPN resins can be used as high release liners, low friction materials, soft‐feel coatings or as convenient one‐package protective coatings. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41709.
Study on physiochemical structure and in vitro release behaviors of doxycycline‐loaded PCL microspheres
Authors: Aydin Ozlem , Aydin Baran , Tezcaner Aysen , Keskin Dilek 
Published: December 2014

ABSTRACTThis study aimed to develop drug delivery system of doxycycline‐loaded polycaprolactone (PCL) microspheres. The investigated microsphere formulation can be considered for local application in bone infections and degenerative joint diseases, which generally require long‐term treatments via systemic drugs. PCL‐14 kDa and 65 kDa were used in microsphere preparation. Before release, the microspheres were characterized by scanning electron microscopy, differential scanning calorimetry, and X‐ray photoelectron spectroscopy. The mean particle size of microspheres was in the range of 74–122 µm and their drug loadings ranged between 10 and 30%. In vitro release profiles were described using the Higuchi and the Korsmeyer–Peppas equations. Diffusion model was applied to experimental data for estimating diffusion coefficients of microspheres; calculated as between 4.5 × 10−10 and 9.5 × 10−10 cm2/s. Although long‐term release from microspheres of PCL‐14 kDa obeyed diffusion model, PCL‐65 kDa microspheres showed this tendency only for some period. Modeling studies showed that the drug release mechanism was mainly dependent on loading and molecular weight differences. Release behavior of PCL‐65 kDa microspheres, however, might be better represented by derivation of a different equation to model for the total release period. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41768
Degradation of poly(vinyl alcohol)‐graft‐lactic acid copolymers by Trichotecium roseum fungus
Authors: Lipsa Rodica , Tudorachi Nita , Grigoraş Vasile Cristian , Vasile Cornelia 
Published: December 2014

ABSTRACTThe biodegradation of poly(vinyl alcohol) and poly(vinyl alcohol)‐graft‐lactic acid copolymers was analyzed, using Trichotecium roseum fungus. The samples were examined during biodegradation at different periods of exposure. Structural modifications of the biodegraded samples were investigated by Fourier transform infrared‐attenuated total reflectance spectroscopy, and the surface morphology was investigated by scanning electron microscopy. The static light scattering results concluded that the weight average molecular mass (Mw) of the copolymers increased after biodegradation, because the fractions with low molecular weight of the copolymers were destroyed. The thermal behavior and stability of the samples before and after the biodegradation period were investigated by differential scanning calorimetry (DSC) and thermogravimetric analyses. The thermogravimetric analyses and their derivatives (TG‐DTG) showed that the thermal stability of the biodegraded samples was more raised comparatively to the unbiodegraded ones. The DSC results demonstrated that biodegradation took place in the amorphous domains of the investigated polymer samples and the crystallinity degree increased after 24 biodegradation days. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41777.
Core–shell biopolymer microspheres for sustained drug release
Authors: Tan Liqing , Jiang Tao , Yang Xiaolan , Li Wei , Pan Lijun , Yu Mingan 
Published: December 2014

ABSTRACTIn this work, a core–shell biopolymer microsphere comprising a carvedilol‐loaded yeast cell wall polysaccharides core surrounded by a silk fibroin shell layer is developed to eliminate the risks of using synthetic polymers for drug encapsulation on human health and to avoid burst release and to prolong the release time. Transmission electron microscopy, Fourier‐transform infrared, confocal laser scanning microscope, and phase contrast microscopy analysis indicate that yeast treated with Tris–HCl containing cetyltrimethylammonium bromide, EDTA, and NaCl could provide much larger space for host drug as compared to plasmolyzed cells because the former can help maintain the original shape of yeast cells. In addition, its permeability barrier is significantly altered and nucleus becomes pyknotic. In contrast, plasmolyzed cells can hardly maintain the rigidity and integrity of their cell walls and will finally end up with cell fragments. SEM observation reveals that the carvedilol‐loaded cells maintain very similar shape and size before and after coating with 0.1% silk fibroin. In vitro release studies show that a drug delivery system using the carvedilol‐loaded cells can achieve a sustained drug release up to 20 days probably due to the electrostatic interaction between the positively charged carvedilol and the negatively charged yeast cells at the pH 7.4 and to the stability of the yeast cell helped by silk fibroin that provides an effective diffusion barrier. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41782.
Total Synthesis of Maoecrystal V
Authors: Zhang Wei‐Bin , Lin Guang , Shao Wen‐Bin , Gong Jian‐Xian , Yang Zhen 
Published: December 2014

AbstractMaoecrystal V (1) is a novel diterpenoid, which was originally isolated from the leaves of the Chinese medicinal herb Isodon eriocalyx in 2004 by Sun et al.1 It has been found to be selectively cytotoxic towards HeLa cells, with an IC50 value of 20 ng mL−1. Significant research efforts have been devoted to the synthesis of maoecrystal V because of its intriguing biological properties, rarity in nature, and complex structural features. Herein, we describe our recent investigations, which have culminated in the total synthesis of (±)‐maoecrystal V. The current strategy involved three key steps for the successful construction of the key tetrahydrofuran oxa‐bridge skeleton, including a Wessely oxidative dearomatization, a novel intramolecular Diels–Alder reaction, and a RhII‐catalyzed OH insertion reaction.
A fast sensor for in vivo quantification of cytosolic phosphate in Saccharomyces cerevisiae
Authors: Zhang Jinrui , Sassen Tom , ten Pierick Angela , Ras Cor , Heijnen Joseph J. , Wahl Sebastian Aljoscha 
Published: December 2014

ABSTRACTEukaryotic metabolism consists of a complex network of enzymatic reactions and transport processes which are distributed over different subcellular compartments. Currently, available metabolite measurement protocols allow to measure metabolite whole cell amounts which hinder progress to describe the in vivo dynamics in different compartments, which are driven by compartment specific concentrations. Phosphate (Pi) is an essential component for: (1) the metabolic balance of upper and lower glycolytic flux; (2) Together with ATP and ADP determines the phosphorylation energy. Especially, the cytosolic Pi has a critical role in disregulation of glycolysis in tps1 knockout. Here we developed a method that enables us to monitor the cytosolic Pi concentration in S. cerevisiae using an equilibrium sensor reaction: maltose + Pi < = > glucose + glucose‐1‐phosphate. The required enzyme, maltose phosphorylase from L. sanfranciscensis was overexpressed in S. cerevisiae. With this reaction in place, the cytosolic Pi concentration was obtained from intracellular glucose, G1P and maltose concentrations. The cytosolic Pi concentration was determined in batch and chemostat (D = 0.1 h−1) conditions, which was 17.88 µmol/gDW and 25.02 µmol/gDW, respectively under Pi‐excess conditions. Under Pi‐limited steady state (D = 0.1 h−1) conditions, the cytosolic Pi concentration dropped to only 17.7% of the cytosolic Pi in Pi‐excess condition (4.42 µmol/gDW vs. 25.02 µmol/gDW). In response to a Pi pulse, the cytosolic Pi increased very rapidly, together with the concentration of sugar phosphates. Main sources of the rapid Pi increase are vacuolar Pi (and not the polyPi), as well as Pi uptake from the extracellular space. The temporal increase of cytosolic Pi increases the driving force of GAPDH reaction of the lower glycolytic reactions. The novel cytosol specific Pi concentration measurements provide new insight into the thermodynamic driving force for ATP hydrolysis, GAPDH reaction, and Pi transport over the plasma and vacuolar membranes. Biotechnol. Bioeng. 2015;112: 1033–1046. © 2014 Wiley Periodicals, Inc.
Characterization of the Gene Cluster CYP264B1‐geoA from Sorangium cellulosum So ce56: Biosynthesis of (+)‐Eremophilene and Its Hydroxylation
Authors: Schifrin Alexander , Ly Thuy T. B. , Günnewich Nils , Zapp Josef , Thiel Verena , Schulz Stefan , Hannemann Frank , Khatri Yogan , Bernhardt Rita 
Published: December 2014

AbstractTerpenoids can be found in almost all forms of life; however, the biosynthesis of bacterial terpenoids has not been intensively studied. This study reports the identification and functional characterization of the gene cluster CYP264B1–geoA from Sorangium cellulosum So ce56. Expression of the enzymes and synthesis of their products for NMR analysis and X‐ray diffraction were carried out by employing an Escherichia coli whole‐cell conversion system that provides the geoA substrate farnesyl pyrophosphate through simultaneous overexpression of the mevalonate pathway genes. The geoA product was identified as a novel sesquiterpene, and assigned NMR signals unambiguously proved that geoA is an (+)‐eremophilene synthase. The very tight binding of (+)‐eremophilene (∼0.40 μM), which is also available in S. cellulosum So ce56, and its oxidation by CYP264B1 suggest that the CYP264B1–geoA gene cluster is required for the biosynthesis of (+)‐eremophilene derivatives.
Supramolecular Encapsulation of Neutral Diazoacetate Esters and Catalyzed 1,3‐Dipolar Cycloaddition Reaction by a Self‐Assembled Hexameric Capsule
Authors: La Sorella Giorgio , Sperni Laura , Strukul Giorgio , Scarso Alessandro 
Published: December 2014

AbstractDiazoacetate esters proved to be suitable neutral guests for the self‐assembled resorcin[4]arene hexameric capsule. The hydrogen‐bonded supramolecular host catalyzed the 1,3‐dipolar cycloaddition reaction between diazoacetate esters and electron‐poor alkenes such as acrolein, acrylonitrile, predominantly trans‐crotonaldehyde, trans‐2‐hexenal, methyl, and butyl acrylate, which led to the corresponding 4,5‐dihydro‐1H‐pyrazole derivatives. The cycloaddition reaction occurred within the cavity of the capsule. In fact, substantial inhibition of the catalytic activity was observed by employing tetraethylammonium tetrafluoroborate characterized by greater affinity for the hexameric capsule as a competitive guest; its presence inhibited access of the substrates. The 1,3‐dipolar cycloaddition reaction between diazoacetate esters and acrylate esters of different lengths showed a significant degree of substrate selectivity owing to the encapsulation of the reagents before the cycloaddition reaction.
Synthesis of Nanocrystalline CeO2 with High Surface Area by the Taguchi Method and its Application in Methanation
Authors: Nematollahi Behzad , Rezaei Mehran , Nemati Lay Ebrahim 
Published: December 2014

AbstractMesoporous nanocrystalline cerium(IV) oxide (CeO2) with high surface area was synthesized by precipitation using a cationic surfactant and employed as support for a nickel catalyst in CO methanation. The preparation factors of CeO2 were optimized by the Taguchi method to achieve a sample with high surface area. The obtained results reveal that the sample prepared under optimized conditions has a mesoporous structure with high surface area and crystallite size. The addition of a surfactant significantly influences the structural properties of CeO2 and improves the specific surface area. The optimized sample was employed as support for a nickel catalyst in CO methanation reaction. The prepared catalyst possessed a high activity compared to a commercial methanation catalyst.
Combustion and Agglomeration Characteristics of the Residue from Corn Stalk‐Based Cellulosic Ethanol
Authors: Ren Qiangqiang , Li Shiyuan , Wang Dongyu , Bao Shaolin , Lu Qinggang 
Published: December 2014

AbstractLignocellulose is considered an efficient raw material to produce fuel ethanol. Clean utilization of the solid residue derived from lignocellulose‐based fuel ethanol is important for the biomass‐to‐ethanol production chain. Combustion characteristics of the residue originating from corn stalk‐based cellulosic ethanol are studied in a circulating fluidized bed. Results indicate that circulating fluidized‐bed combustion is an effective and stable way to burn the residue with high moisture content. CO emission during biomass combustion in a circulating fluidized bed is low in the range of several ppm. NO and N2O are the major pollutants during residue combustion. The optimal combustion temperature is limited to avoid agglomeration and reduce pollutant emission. Design data and theoretical support for design and operation of the residue combustion circulating fluidized‐bed boiler are provided.