bluuebunny/crossref_metadata_2025 huggingface dataset:
Advanced Core–Shell Nanoparticle Catalysts for Efficient Organic Transformations
Authors: Mitsudome Takato , Kaneda Kiyotomi
Published: March 2013

With the advent of nanotechnology, the rational design of core–shell nanoparticle catalysts has attracted enormous attention. This Minireview describes recent progress in designs of state‐of‐the‐art core–shell nanostructured catalysts with active species in the core for efficient organic transformations. These core–shell catalysts demonstrate high potential for excellent durability against aggregation due to the encapsulation process as well as unique functionalities for different purposes such as magnetic properties for easy separation, porous shell adjustability for shape selectivity, stimuli responsiveness and strong metal–support interaction for high chemoselectivity, and site isolation for the development of one‐pot catalysts.
Ruthenium(II)‐Catalyzed Hydrogen Generation from Formic Acid using Cationic, Ammoniomethyl‐Substituted Triarylphosphine Ligands
Authors: Gan Weijia , Snelders Dennis J. M. , Dyson Paul J. , Laurenczy Gábor
Published: March 2013

The selective catalytic decomposition of formic acid into hydrogen and carbon dioxide has been achieved in water under mild conditions. For the first time, a ruthenium ion in combination with a series of oligocationic, ammoniomethyl‐substituted triarylphosphines was used for this reaction, as opposed to previously used anionic and neutral ligands. These cationic phosphines vary in size and charge and therefore have different hydrophilic, steric, and electronic properties. Excellent catalytic activities were achieved in the formic acid dehydrogenation reaction and correlations between the activity and the ligand structure were made. High turnover frequencies (TOFs) of 1950 h−1 and turnover numbers (TONs) over 10 000 were obtained through optimization of the catalytic system.
Hydroxypalladation Precedes the Rate‐Determining Step in the Wacker Oxidation of Ethene
Authors: Imandi Venkataramana , Kunnikuruvan Sooraj , Nair Nisanth N.
Published: March 2013

The complete reaction mechanism and kinetics of the Wacker oxidation of ethene in water under low [Cl−], [PdII], and [CuII] conditions are investigated in this work by using ab initio molecular dynamics. These extensive simulations shed light on the molecular details of the associated individual steps, along two different reaction routes, starting from a series of ligand‐exchange processes in the catalyst precursor PdCl42− to the final aldehyde‐formation step and the reduction of PdII. Herein, we report that hydroxylpalladation is not the rate‐determining step and is, in fact, in equilibrium. The newly proposed rate‐determining step involves isomerization and follows the hydroxypalladation step. The mechanism proposed herein is shown to be in excellent agreement with the experimentally observed rate law and rate. Moreover, this mechanism is in consensus with the observed kinetic isotope effects. This report further confirms the outer‐sphere (anti) hydroxypalladation mechanism. Our calculations also ratify that the final product formation proceeds through a reductive elimination, assisted by solvent molecules, rather than through β‐hydride elimination.
ChemInform Abstract: Stereoselective Synthesis of cis‐Fused Perhydrofuro[2,3‐b]furan Derivatives from Sugar‐Derived Allyl Vinyl Ethers.
Authors: Sridhar Perali Ramu , Reddy Gadi Madhusudhan , Seshadri Kalapati
Published: March 2013

A stereoselective method for the synthesis of the title compounds like (IV) is developed involving Claisen rearrangement followed by a one‐pot ozonolysis and acid‐mediated acetalization.
ChemInform Abstract: Synthesis of Pyrazolo[3,4‐b]pyridin‐6‐ones
Authors: Komarova Elena S. , Makarov Vadim A. , Granik Vladimir G. , Parkanyi Cyril
Published: March 2013

Review: 135 refs.
ChemInform Abstract: Metal‐Free Oxidative C(sp3)—H Bond Couplings as Valuable Synthetic Tools for C—C Bond Formations
Authors: Rohlmann Renate , Garcia Mancheno Olga
Published: March 2013

Review: 29 refs.
ChemInform Abstract: S‐Adenosyl‐Methionine‐Dependent Methyltransferases: Highly Versatile Enzymes in Biocatalysis, Biosynthesis and Other Biotechnological Applications
Authors: Struck Anna‐Winona , Thompson Mark L. , Wong Lu Shin , Micklefield Jason
Published: March 2013

Review: 121 refs.
Depletion of Liquefied Petroleum Gas from Natural Gas by Zeolite Membranes
Authors: Neubauer Katja , Lubenau Udo , Hecker Christine , Lücke Bernhard , Paschek Dietmar , Wohlrab Sebastian
Published: March 2013

Die Abreicherung höherer Kohlenwasserstoffe aus Erdgas oder Erdölbegleitgasen ist ein unablässiger Schritt vor der Einspeisung in das Endverbrauchernetz. Membrantechnologien könnten dabei als Ersatz für energieintensive und kostspielige Reinigungsmethoden eingesetzt werden. Vor diesem Hintergrund wurde die entsprechende Eignung zeolithischer MFI‐Membranen untersucht und der Einfluss von Membranträgergeometrie, Gaszusammensetzung, Temperatur und Druck auf die Trennung von Methan/n‐Butan‐Mischungen getestet.
A New View of the Initiation and Propagation in Anionic Polymerization
Authors: Zheng Anna , Chen Bo , Hu Dihang , Guan Yong , Wei Dafu , Li Shuzhao , Ji Dandan
Published: March 2013

This work confirms the new view of the initiation and propagation mechanism of the anionic polymerization previously proposed, based on the investigation of anionic bulk‐polymerization of styrene and α‐methyl styrene with the help of a self designed microflow device and characterized by GPC and in situ 7Li NMR. It was found that n‐BuLi tended to form the hexameric‐aggregated structure and even to form the huge aggregated structure based on the former. These aggregations of initiators could directly initiate the anionic polymerization and form the supramolecule aggregations. The supramolecule aggregations inevitably blocked the diffusion of the monomers to the ion‐pairs and resulted in a stationary‐conversion platform. Then the aggregators were dissociated completely into equal binary‐aggregated species, and the polymerization continued again rapidly before the termination. Tetrahydrofuran (THF) acted as the electron donator, which could push the electron cloud to Li cation and make the aggregated ring of the active species rather loosened and facilitated the monomer to insert in. Therefore, a little THF can greatly promote the anionic polymerization. However, further addition of THF might block the channel between the ion‐pairs and decrease the propagation rate. It was also found that the aggregated structure of the active species during the anionic polymerization only depends on the initiator aggregations which were formed before the polymerization.
Microfluidic Device: A Miniaturized Platform for Chemical Reactions
Authors: Tu Qin , Pang Long , Zhang Yanrong , Yuan Maoseng , Wang Jianchun , Wang Dongen , Liu Wenming , Wang Jinyi
Published: March 2013

Microfluidic devices, as a new miniaturized platform stemming from the field of micro‐electromechanical systems, have been used in many disciplines. In the field of chemical reactions, microfluidic device‐based microreactors have shown great promise in building new chemical technologies and processes with increased speed and reliability and reduced sample consumption and cost. This technology has also become a new and effective tool for precise, high‐throughput, and automatic analysis of chemical synthesis processes. Compared with conventional chemical laboratory batch methodologies, microfluidic reactors have a number of features, such as high mixing efficiency, short reaction time, high heat‐transfer coefficient, small reactant volume, controllable residence time, and high surface‐to‐volume ratio, among others. Combined with recent advances in microfluidic devices for chemical reactions, this review aims to give an overview of the features and applications of microfluidic devices in the field of chemical synthesis. It also aims to stimulate the development of microfluidic device applications in the field of chemical reactions.
Risk Factors, Therapeutic Approaches, and In‐Hospital Outcomes in Mexicans With ST‐Elevation Acute Myocardial Infarction: The RENASICA II Multicenter Registry
Authors: Juárez‐Herrera Úrsulo , Jerjes‐Sánchez Carlos ,   and The RENASICA II Investigators
Published: March 2013

Background

Ischemic heart disease is a growing health problem in Latin America. We aimed to analyze risk factors, acute management, and short‐term outcome of Mexicans with ST‐elevation myocardial infarction (STEMI).

Hypothesis

Modifiable risk factors are associated with the occurrence of STEMI in Mexicans, and potentially preventable acute complications are responsible for most short‐term deaths.

Methods

Among 8600 patients enrolled in Registro Nacional de los Síndromes Coronarios Agudos II (RENASICA II) with a suspected acute coronary syndrome, we analyzed 4555 patients (56%; age 21–100 y) with confirmed STEMI who presented within 24 hours from symptoms' onset.

Results

Smoking (66%), hypertension (50%), and diabetes (43%) were the main risk factors. Most patients (74%) presented with Killip class I (class IV in 4%). Anterior‐located STEMI occurred in 56% of cases, and posterior‐inferior in 40% of cases. Significant Q waves were present in 43%, right bundle branch block in 7%, left bundle branch block in 5%, first‐degree atrioventricular block in 2%, and high‐degree atrioventricular block in 2%. A total of 1685 (37%) patients received fibrinolytic therapy (streptokinase, 82%; alteplase, 17%; tenecteplase, 1%), with 31% of patients receiving therapy in <2 hours, 36% in 2–4 hours, 19% in 4–6 hours, and 15% in >6 hours. Thirty percent of patients received either percutaneous coronary intervention or coronary artery bypass grafting during hospitalization. Major adverse cardiovascular events were recurrent ischemia (12%), reinfarction (4%), cardiogenic shock (4%), and stroke (1%). The main predictors of 30‐day mortality (10%) in multivariate analysis were age ≥65 years (odds ratio [OR]: 2.47, 95% confidence interval [CI]: 1.94‐3.13), Killip class IV (OR: 10.60, 95% CI: 6.09‐18.40), and cardiogenic shock (OR: 18.76, 95% CI: 10.60‐33.20).

Conclusions

Largely modifiable risk factors and preventable short‐term complications are responsible for most STEMI cases and outcomes in this Mexican population.
Efficiency of Pleurotus florida Laccase on Decolorization and Detoxification of the Reactive Dye Remazol Brilliant Blue R (RBBR) under Optimized Conditions
Authors: Sathishkumar Palanivel , Balan Kannan , Palvannan Thayumanavan , Kamala‐Kannan Seralathan , Oh Byung‐Taek , Rodríguez‐Couto Susana
Published: March 2013

Laccase from the white‐rot fungus Pleurotus florida, produced under solid‐state fermentation conditions, was used for the decolorization of reactive dye Remazol Brilliant Blue R (RBBR). RBBR was decolorized up to 46% by P. florida laccase alone in 10 min. In the presence of N‐hydroxybenzotriazole (HBT), the rate of decolorization was enhanced 1.56‐fold. Central composite design of response surface methodology with four variables namely, dye, enzyme, redox mediator concentrations, and time at five levels was applied to optimize the RBBR decolorization. The predicted optimum level of variables for maximum RBBR decolorization (87%) was found to be 52.90 mg L−1 (RBBR), 1.87 U mL−1 (laccase), 0.85 mM (HBT), and 7.17 min (time), respectively. The validation results showed that the experimental value of RBBR decolorization (82%) was close to the predicted one. The disappearance of C–N and C–X groups, and a small shift in N–H groups in Fourier‐transform infra red (FTIR) spectroscopy confirms the degradation of RBBR chromophore by laccase enzyme. The phytotoxicity of RBBR was considerably reduced after the treatment with laccase. RBBR decolorization kinetics; Km and Vmax were calculated to be 145.82 mg L−1 and 24.86 mg L−1 min, respectively.
uCyt+/ImmunoCyt and cytology in the detection of urothelial carcinoma
Authors: Comploj Evi , Mian Christine , Ambrosini‐Spaltro Andrea , Dechet Christopher , Palermo Salvatore , Trenti Emanuela , Lodde Michele , Horninger Wolfgang , Pycha Armin
Published: March 2013

BACKGROUND

The aim of the current study was to report the results of 7422 uCyt+/ImmunoCyt and cytology analyses that were performed over the course of 9 years at the study institution for the evaluation and follow‐up of patients with urothelial carcinoma.

METHODS

Between January 2002 and March 2011, 2217 patients with a mean age of 69.5 years (range, 15 years‐99 years) were enrolled in the current study. All patients seen for the follow‐up of bladder and/or upper tract urothelial cancer as well as those with a history that was suspicious for bladder cancer were recruited. In all patients, a voided urinary cytology and uCyt+/ImmunoCyt test was performed. Patients underwent routine cystoscopy as well as cystoscopy when cytology and/or the uCyt+/ImmunoCyt test yielded positive results. Lesions that were detected cystoscopically were biopsied and removed transurethrally. A total of 7422 uCyt+/ImmunoCyt and cytology analyses were performed.

RESULTS

Of the 7422 uCyt+/ImmunoCyt tests and cytologies that were performed, 7075 (95.3%) were considered adequate. A total of 578 patients (with 1156 analyses) underwent biopsy and 728 (63%) samples had a histologically proven urothelial carcinoma. Overall sensitivity was 34.5% for cytology, 68.1% for uCyt+/ImmunoCyt, and 72.8% for the 2 tests combined. Overall specificity was 97.9% for cytology, 72.3% for uCyt+/ImmunoCyt, and 71.9% for the 2 tests combined. Cytology and the uCyt+/ImmunoCyt test together had an overall sensitivity of 72.8%, with 59% for grade 1, 77% for grade 2, and 90% for grade 3 tumors (according to the 1973 World Health Organization grading classification system).

CONCLUSIONS

On the basis of their 9‐year experience, the authors confirm the value of uCyt+/ImmunoCyt and cytology analyses in the follow‐up of patients with non–muscle‐invasive urothelial cancer. This could potentially reduce the number and cost of routine cystoscopic examinations in patients who are followed for bladder carcinoma. Cancer (Cancer Cytopathol) 2013;121:392–397. © 2013 American Cancer Society.
Semantic interpretation of color differences and color‐rendering indices
Authors: Bodrogi Peter , Brückner Stefan , Krause Nathalie , Khanh Tran Quoc
Published: March 2013

A series of visual experiments were carried out to rate the similarity of color appearance of two color stimuli on categorical and continuous semantic rating scales. Pairs of color stimuli included two copies of the same colored real or artificial object illuminated by a test light source and a reference light source. A formula was developed to predict a category of color similarity (e.g., “moderate” or “good”) from an instrumentally measured color difference. Given a numeric value of a color difference between the two members of a pair of colors, for example, 2.07, the formula is able to predict a category of color similarity, for example, “good.” Because color‐rendering indices are based on color differences, the formula could be applied to interpret the values of the new color‐rendering index (n‐CRI or CRI2012) in terms of such semantic categories. This semantic interpretation enables nonexpert users of light sources to understand the color‐rendering properties of light sources and the differences on the numeric scale of the color‐rendering index in terms of regular language. For example, a numeric value of 87 can be interpreted as “good.”  © 2013 Wiley Periodicals, Inc. Col Res Appl, 39, 252–262, 2014; Published online 14 March 2013 in Wiley Online Library (wileyonlinelibrary.com). DOI 10.1002/col.21798
Unbiased Photoelectrochemical Water Splitting in Z‐Scheme Device Using W/Mo‐Doped BiVO4 and ZnxCd1−xSe
Authors: Park Hyun S. , Lee Heung Chan , Leonard Kevin C. , Liu Guanjie , Bard Allen J.
Published: March 2013

Photoelectrochemical water splitting to generate H2 and O2 using only photon energy (with no added electrical energy) has been demonstrated with dual n‐type‐semiconductor (or Z‐scheme) systems. Here we investigated two different Z‐scheme systems; one is comprised of two cells with the same metal‐oxide semiconductor (W‐ and Mo‐doped bismuth vanadate), that is, Pt‐W/Mo‐BiVO4, and the other is comprised of the metal oxide and a chalcogenide semiconductor, that is, Pt‐W/Mo‐BiVO4 and Zn0.2Cd0.8Se. The redox couples utilized in these Z‐scheme configurations were I−/IO3− or S2−/Sn2−, respectively. An electrochemical analysis of the system in terms of cell components is shown to illustrate the behavior of the complete photoelectrochemical Z‐scheme water‐splitting system. H2 gas from the unbiased photolysis of water was detected using gas chromatography–mass spectroscopy and using a membrane‐electrode assembly. The electrode configuration to achieve the maximum conversion efficiency from solar energy to chemical energy with the given materials and the Z‐scheme is discussed. Here, the possibilities and challenges of Z‐scheme unbiased photoelectrochemical water‐splitting devices and the materials to achieve practical solar‐fuel generation are discussed.
Panchromatic Quantum‐Dot‐Sensitized Solar Cells Based on a Parallel Tandem Structure
Authors: Zhou Na , Yang Yueyong , Huang Xiaoming , Wu Huijue , Luo Yanhong , Li Dongmei , Meng Qingbo
Published: March 2013

A tandem‐structure sensitized solar cell, comprising different inorganic semiconductor quantum dots (QDs) as sensitizers in two different compartments, has been designed for the first time with the aim of extending the light‐absorption range of current technologies. In this system, the CdS/CdSe co‐sensitized quantum‐dot solar cell (QDSC) is in the upper part, whereas the PbS/CdS co‐sensitized QDSC is in the lower part; these are connected in parallel with each other. In the middle of the tandem solar cell, a Cu2S mesh counter electrode is employed. By optimizing the electrode thickness and QD‐deposition time, short‐circuit photocurrent density values of as high as 25.12 mA cm−2 have been achieved; this value is nearly equal to the sum of the two constituent QD‐sensitized devices and gives rise to a solar power‐conversion efficiency of 5.06 %.
Circulating microRNA as a biomarker of human growth hormone administration to patients
Authors: Kelly Brian N. , Haverstick Doris M. , Lee Jae K. , Thorner Michael O. , Vance Mary Lee , Xin Wenjun , Bruns David E.
Published: March 2013

Circulating microRNAs (miRNAs) in plasma are being studied for use as biomarkers of specific diseases and as markers of administration of pharmaceutical agents. Administration of recombinant human growth hormone (rhGH) is prohibited by sporting authorities, but it continues to be used by athletes attempting to gain an unfair advantage in athletic competition. Current methods for detection of rhGH use rely on immunoassay technology and are limited by a short time‐frame in which detection of rhGH is possible. We hypothesized that administration of rhGH would alter expression of circulating miRNAs and that any changes could be detected. To identify potential miRNA targets, we utilized miRNA microarrays for screening. Confirmatory testing used real‐time reverse‐transcriptase (RT) quantitative PCR (qPCR) assays of selected miRNAs in 35 plasma samples obtained from (1) individuals with no known pituitary disorders, (2) patients with excess GH production, and (3) patients receiving therapeutic replacement doses of rhGH. We identified and confirmed four miRNAs that were differentially expressed in all individuals using therapeutic replacement doses of rhGH when compared to individuals with naturally high levels of GH and normal controls. This study further develops the hypothesis that circulating miRNAs may be used as biomarkers for detection of doping in sports. Copyright © 2013 John Wiley & Sons, Ltd.
Ecological response and hydrological mechanism of desert riparian forest in inland river, northwest of China
Authors: Li Weihong , Zhou Honghua , Fu Aihong , Chen Yapeng
Published: March 2013

The interactive relationships of ecological and hydrological processes on individual plant growth and development as well as community succession have been a main focus of research in plant ecohydrology. In this paper, we firstly explore the spatial difference of the desert riparian ecosystems as distance to the river in the arid inland Tarim River Basin and then investigate the response of vegetation communities to emergent ecological water conveyances. Results showed that the decreasing groundwater table is the main driving force for vegetation degradation. Herbs exhibit degradation when the groundwater table is 4–6 m below the surface, whereas trees do not exhibit degradation until the groundwater table exceeds 6 m from the soil surface, in the lower reaches of the Tarim River. In addition, the structure of the plant community is controlled by the depth of the groundwater table. The mixed trees/shrubs/herbs structure is distributed in areas where the groundwater table is between 2 and 4 m in depth, the trees/shrubs structure is distributed in areas where the groundwater depth is 4–8 m and the simple structure of degraded Populus euphratica/Tamarix chinensis dominates the areas where the groundwater depth is >8 m. After ecological water conveyance, the Phraginites communis leaf weight, length and width decrease with the increasing distance from the river channel. The length of current‐year twigs and average number of leaves of P. euphratica are significantly greater in the upstream section of the lower reach than in the downstream section of the lower reach. We concluded that the ecologically suitable groundwater depth for P. euphratica and T. chinensis is 2–4 m and the critical groundwater depth for drought stress is about 9 m. Copyright © 2013 John Wiley & Sons, Ltd.
Self‐Assembly of Arylboronate Esters with Pyridyl Side Chains
Authors: Sheepwash Erin , Zhou Kai , Scopelliti Rosario , Severin Kay
Published: March 2013

Boronate esters that contain N‐donor groups are self‐complementary structures, which can assemble by means of dative boron–nitrogen bonds to form macrocycles or polymers. Herein, we describe the synthesis of dioxaborinanes and benzodioxaboroles containing pyridyl side chains. In the solid state, the dioxaborinanes were found to exist predominantly as monomers. Upon crystallization, aggregation into one‐dimensional polymers was observed, but only for boronate esters that contained electron‐withdrawing groups. The more Lewis acidic benzodioxaboroles, on the other hand, were found to form macrocycles both in solution and in the solid state.
Influence of chloride and glycidyl‐ester on the generation of 3‐MCPD‐ and glycidyl‐esters
Authors: Shimizu Masao , Weitkamp Petra , Vosmann Klaus , Matthäus Bertrand
Published: March 2013

Heating tests of pure diolein with various chloride and glycidyl ester (GE) levels at 240°C were conducted. Tetrabutylammonium chloride (TBAC) was used as a chloride source. The GE levels tended to converge on equilibrium around 100 mg‐as monochloropropane‐1,2‐diol (MCPD)/kg, regardless of the initial GE content, which suggested that the GE level was the result of competitive reactions between generation and decomposition. Chloride content had no influence on GE generation. On the other hand, 3‐MCPD ester levels were greatly influenced by both chloride and initial GE content, and the reactions were estimated to reach completion in the early stage of the heating period due to the run‐out of the chloride source. The conversion ratios of chloride to 3‐MCPD ester were 2–8%. These low ratios indicated that most of the TBAC was converted to inactive compounds for 3‐MCPD ester formation. Not only the quantity but also the type of chloride compound is important to control the 3‐MCPD ester level. Although generation of 3‐MCPD esters via GE was confirmed, practical impact was estimated to be small. However, this pathway should be taken into consideration, because GE is thought to make 3‐MCPD monoester, which could show different bioavailability compared with the diester that predominantly occurs in edible oils.
Synthesis of Cyclic γ‐Amino Acids for Foldamers and Peptide Nanotubes
Authors: Rodríguez‐Vázquez Nuria , Salzinger Stephan , Silva Luis F. , Amorín Manuel , Granja Juan R.
Published: March 2013

Cyclic γ‐amino acids are molecular building blocks of great interest in peptide and foldamer chemistry, as they allow the preparation of new structures that are not found in Nature. In this paper, we describe the synthesis of cyclic γ‐amino acids that have a cis relationship between the amino and the carboxylic acid groups. This arrangement, in most cases, induces the resulting peptides to adopt a flat conformation, which makes them appropriate for the design of foldamers that adopt β‐sheet‐type structures.
Highly Fluorescent, π‐Extended Indenopyrido[2,1‐a]isoindolone Derivatives Prepared by a Palladium‐Catalysed Cascade Reaction
Authors: el abidine Chamas Zein , Marchi Enrico , Modelli Alberto , Fort Yves , Ceroni Paola , Mamane Victor
Published: March 2013

A new family of heterocyclic pentacyclic compounds have been prepared by a cascade reaction involving 2,5‐dihalopyridines and (2‐formylphenyl)boronic acids. Most of the compounds exhibit high quantum yields of fluorescence in dichloromethane. In some cases, small changes in the substitution pattern caused fluorescence quenching. To rationalize this effect, a detailed photophysical study combined with electrochemical and computational studies was performed on four representative derivatives. It appears that the fluorescence quenching is caused by a thermally activated non‐radiative deactivation process that can be prevented in a rigid matrix such as ethanol at 77 K or a PMMA polymer.
Synthesis of Chiral Allylic Thioesters: Enantio‐ and Regioselective Iridium‐Catalyzed Allylations of KSAc
Authors: Gao Ning , Zhao Xiaoming
Published: March 2013

Chiral allylic thioesters were synthesized through a direct iridium‐catalyzed asymmetric allylation of KSAc in the presence of KOAc. This strategy provided branched allylic thioesters in good yields with the high levels of enantioselectivity.
Cucurbit[7]uril Host–Guest Complexes with Biguanidinium Cations in Aqueous Solution
Authors: MacGillivray Brendan C. , Macartney Donal H.
Published: March 2013

The host–guest complexations of a series of biguanidinium cations (metformin and phenformin) and bis(biguanidinium) dications (chlorhexidine and alexidine) by the host molecule cucurbit[7]uril (CB[7]) in aqueous solution have been investigated by 1H NMR spectroscopy and ESI mass spectrometry. Metformin forms both 1:2 and 1:1 host–guest complexes, whereas phenformin forms only a 1:1 complex. The two bis(biguanidinium) dications both form sequential 1:1, 2:1 and 3:1 host–guest complexes, however, the mechanism is different in each case. With chlorhexidine, the first CB[7] binds to the central hexamethylene chain, followed by sequential complexation of the terminal 4‐chlorophenyl groups. With alexidine, the two terminal 2‐ethylhexyl groups are bound first, with the third CB[7] adding only with a concomitant relocation of one CB[7] to the central hexamethylene binding site. The stability constants of the various host–guest complexes were determined by 1H NMR titrations and competitive binding experiments, as well as by the application of a statistical binding model.
β‐Cyclodextrin–Glycerol Dimers: Synthesis and NMR Conformational Analysis
Authors: Legros Vanessa , Vanhaverbeke Cécile , Souard Florence , Len Christophe , Désiré Jérôme
Published: March 2013

The synthesis of new β‐cyclodextrin dimers linked through their primary faces by different glycerol‐like moieties by click chemistry is described. The unusual behaviour of these cyclodextrin–glycerol dimers in aqueous solution has been studied by NMR spectroscopy. We show that, depending on the length of the linking arm between the two cyclodextrins, the dimers could adopt very different conformations in water: symmetrical or pseudo[1]rotaxane‐like structures through one D‐glucopyranose unit tumbling in one β‐cyclodextrin.
Capping α‐Cyclodextrin with Cyclotriveratrylene by Triple Disulfide‐Bridge Formation
Authors: Brégier Frédérique , Lavalle Juliette , Chambron Jean‐Claude
Published: March 2013

Disulfide‐bond formation is an expeditious coupling reaction to make macropolycyclic symmetrical receptors. It is used here for the preparation of unsymmetrical cavitands based on α‐cyclodextrin (α‐CDX) and cyclotriveratrylene (CTV) analogues. Accordingly, diastereomeric hemicryptophanes 2a and 2b were obtained in 11 % isolated yield by the iodine oxidation of a 1:1 mixture of racemic cyclotrithiophenolene (3) and the C3‐symmetric trithiol derivative of permethylated α‐cyclodextrin (PM α‐CDX) 4. Remarkably, the target hemicryptophanes were obtained in a 5:3 diastereomeric ratio. The reaction produced mainly (34 %) a singly disulfide‐bridged PM α‐CDX dimer 7, however no traces of triply disulfide‐bridged head‐to‐head PM α‐CDX dimer were detected. In addition, the formation of the known S‐cryptophane‐0.0.0 was observed.
Brønsted Acid Catalyzed Intramolecular Hydroarylation for the Synthesis of Cycloalkenyl Selenides and Tellurides
Authors: Eom Dahan , Park Sangjune , Park Youngchul , Lee Kooyeon , Hong Gilbert , Lee Phil Ho
Published: March 2013

Trifluoromethanesulfonic acid catalyzed intramolecular hydroarylation of alkynyl selenides and tellurides is developed for the preparation of cycloalkenyl selenide and telluride derivatives through a selective 6‐ and 7‐endo mode. The cycloalkenyl selenides and tellurides can be easily converted into a wide range of other valuable functionalities, including cyclic olefins, allylic alcohols, enynes, 1,3‐dienes, and α,β‐unsaturated aldehydes.
Automated immobilized metal affinity chromatography system for enrichment of Escherichia coli phosphoproteome
Authors: Qu Yi , Wu Si , Zhao Rui , Zink Erika , Orton Daniel J. , Moore Ronald J. , Meng Da , Clauss Therese R. W. , Aldrich Joshua T. , Lipton Mary S. , Paša‐Tolić Ljiljana
Published: March 2013

Enrichment of bacterial phosphopeptides is an essential step prior to bottom‐up mass spectrometry‐based analysis of the phosphoproteome, which is fundamental to understanding the role of phosphoproteins in cell signaling and regulation of protein activity. We developed an automated immobilized metal affinity chromatography (IMAC) system to enrich strong cation exchange‐fractionated phosphopeptides from the soluble proteome of Escherichia coli MG1655 grown on minimal medium. Initial demonstration of the system resulted in identification of 75 phosphopeptides covering 52 phosphoproteins. Consistent with previous studies, many of these phosphoproteins are involved in the carbohydrate portion of central metabolism. The automated system utilizes a large capacity IMAC column that can effectively enrich phosphopeptides from a bacterial sample by increasing peptide loading and reducing the wash time. An additional benefit of the automated IMAC system is reduced labor and associated costs.
Capillary electrophoresis for monitoring bioprocesses
Authors: Alhusban Ala A. , Breadmore Michael C. , Guijt Rosanne M.
Published: March 2013

Chemical characterization and monitoring of fermentation broths and cell culture media provide significant information on the changes occurring within these complex and dynamic systems. Analytical methods based on CE in capillaries and microchips are attractive for integration in instrumental tools to obtain this critical data, improving the understanding and control of bioprocesses. In this review, the use of CE for chemical characterization and monitoring fermentations is discussed, organized by analyte class, including organic acids, pharmaceuticals, proteins, sugars, amino acids, and metabolites published between 1992 and October 2012. A section is dedicated to the roles CE plays throughout the wine making process, where applications range from characterization and increase in fundamental understanding of the fermentation to forensic applications, verifying the authenticity of the wine.
Identification of an unusually sulfated tetrasaccharide chondroitin/dermatan motif in mouse brain by combining chip‐nanoelectrospray multistage MS2‐MS4 and high resolution MS
Authors: Flangea Corina , Petrescu Andrei J. , Seidler Daniela G. , Munteanu Cristian V. A. , Zamfir Alina D.
Published: March 2013

Chondroitin sulfate (CS)/dermatan sulfate (DS) are often found in nature as hybrid glycosaminoglycan chains in various proteoglycans. In the recent years, several MS methods were developed for the determination of over‐, regular‐, and undersulfated CS/DS chains. In the present work, the released hybrid CS/DS isolated and purified from mouse brain were digested with chondroitin AC lyase. The depolymerized chains were separated by gel filtration chromatography. Collected tetrasaccharides were analyzed by fully automated (NanoMate robot) chip‐based nanoESI high capacity ion trap multistage MS (MS2–MS4) recently introduced in glycosaminoglycan research by our laboratory. The obtained data were confirmed by high resolution MS screening and MS/MS performed on QTOF instrument. NanoMate‐high capacity ion trap MS and QTOF MS screening revealed the presence in the mixture of oversulfated tetrasaccharides bearing three and four sulfate groups as well as traces of regularly and undersulfated hexamers. Additionally, several saturated species as either tetramers or hexamers exhibiting different sulfate content were discovered in the analyzed fraction. This diversity of the sulfation status indicates that the mouse brain might contain several types of proteoglycans. The molecular ions corresponding to trisulfated‐[4,5Δ‐GlcA‐GalNAc‐IdoA‐GalNAc] were subjected to multistage fragmentation by CID. Sequence analysis data allowed for the postulation of two rare structural motifs: [4,5Δ‐GlcA‐GalNAc(4S)‐IdoA(2S,3S)‐GalNAc] and [4,5Δ‐GlcA‐GalNAc‐IdoA(2S,3S)‐GalNAc(4S)], previously not reported in neural tissue.
Bacterial FadR and synthetic promoters function as modular fatty acid sensor‐ regulators in Saccharomyces cerevisiae
Authors: Teo Wei Suong , Hee Kai Sheng , Chang Matthew Wook
Published: March 2013

Fatty acid derivatives have ideal properties for use as drop‐in biofuels. An effective strategy in engineering microbial cells to maximize productivity and yield involves dynamic control of protein production in response to concentrations of key intermediates. In Saccharomyces cerevisiae, the activities of the native transcription factors responsive to fatty acids are repressed in the presence of a glucose carbon source. In order to develop a modular fatty acid regulation system in S. cerevisiae, we constructed fatty acid/fatty acyl‐CoA biosensors in S. cerevisiae using bacterial FadR transcriptional repressors and yeast synthetic promoters containing DNA‐binding operators. We demonstrated the functionality of FadR repressors in S. cerevisiae, and tuned the sensing system by varying the promoter strength upstream to the FadR‐coding sequence by varying the number of operator sites in the synthetic promoter and by using FadR from two bacterial sources (Escherichia coli and Vibrio cholerae) with different ligand sensitivities. We envision that our fatty acid/fatty acyl‐CoA biosensors can be used for regulation of protein expression based on the availability of fatty acid intermediates, which will assist in balancing of cellular metabolism during fatty acid derivatives production in yeast.
Low Temperature Electrode Materials Synthesized by Citrate Precursor Method for Solid Oxide Fuel Cells
Authors: Nath M. A. , Hameed A. S. , Chockalingam R. , Basu S. , Ganguli A. K.
Published: March 2013

Homogeneous nanocrystalline NiO–Ce0.9Ln0.1O2–δ (Ln = La, Sm, Gd, and Pr) composite anode and nanocrystalline Ce0.9Gd0.1O2–δ electrolyte material have been successfully synthesized by citrate precursor method. LSCF has been synthesized by conventional solid state method and used as cathode material in our studies. The synthesized powders have been characterized by powder X‐ray diffraction, microscopy, and surface area studies. The average crystallite size of the anode materials has been found to be in the range of 5–15 nm by HRTEM. Highly dense electrolyte and porous electrode materials have been observed by FESEM and confirmed by BET surface area studies. Three cells have been fabricated successfully. Based on the performance of the three cells containing three different anode materials we have achieved better electrochemical characteristics in Ni–GDC with maximum power density of 302 mW cm–2 and open circuit voltage of 1.012 V at 500 °C. The difference in the performance of the cells containing Ni–GDC as compared to Ni–LDC and Ni–SDC anode is due to changes in the microstructure and crystallite size of anode which affects the electrochemical performance of the cells. The performances of all the cells containing nanocomposite powders are suitable anode materials for low temperature SOFCs.
Phosphorus cycling in the Sargasso Sea: Investigation using the oxygen isotopic composition of phosphate, enzyme‐labeled fluorescence, and turnover times
Authors: McLaughlin Karen , Sohm Jill A. , Cutter Gregory A. , Lomas Michael W. , Paytan Adina
Published: March 2013

Dissolved inorganic phosphorus (DIP) concentrations in surface water of vast areas of the ocean are extremely low (<10 nM) and phosphorus (P) availability could limit primary productivity in these regions. We explore the use of oxygen isotopic signature of dissolved phosphate (δ18OPO4) to investigate biogeochemical cycling of P in the Sargasso Sea, Atlantic Ocean. Additional techniques for studying P dynamics including 33P‐based DIP turnover time estimates and percent of cells expressing alkaline phosphatase (AP) activity as measured by enzyme‐labeling fluorescence are also used. In surface waters, δ18OPO4 values were lower than equilibrium by 3–6‰, indicative of dissolved organic phosphorous (DOP) remineralization by extracellular enzymes. An isotope mass balance model using a variety of possible combinations of enzymatic pathways and substrates indicates that DOP remineralization in the euphotic zone can account for a large proportion on P utilized by phytoplankton (as much as 82%). Relatively short DIP turnover times (4–8 h) and high expression of AP (38–77% of the cells labeled) are consistent with extensive DOP utilization and low DIP availability in the euphotoc zone. In deep water where DOP utilization rates are lower, δ18OPO4 values approach isotopic equilibrium and DIP turnover times are longer. Our data suggests that in the euphotic zone of the Sargasso Sea, DOP may be appreciably remineralized and utilized by phytoplankton and bacteria to supplement cellular requirements. A substantial fraction of photosynthesis in this region is supported by DOP uptake.
New potential carbon emission reduction enterprises in China: deep geological storage of CO2 emitted through industrial usage of coal in China
Authors: Zeng Rongshu , Vincent Ceri Jayne , Tian Xingyou , Stephenson Mike H , Wang Shu , Xu Wendong
Published: March 2013

Deep geological storage of carbon dioxide (CO2) could offer an essential solution to mitigate greenhouse gas emissions from the continued use of fossil fuels. Currently, CO2 capture is both costly and energy intensive; it represents about 60% of the cost of the total carbon capture and storage (CCS) chain which is causing a bottleneck in advancement of CCS in China. This paper proposes capturing CO2 from coal chemical plants where the CO2 is high purity and relatively cheap to collect, thus offering an early opportunity for industrial‐scale full‐chain CCS implementation. The total amount of high concentration CO2 that will be emitted (or is being emitted) by the coal chemical factories approved by the National Development and Reform Commission described in this paper is 42 million tonnes. If all eight projects could utilize CCS, it would be of great significance for mitigating greenhouse gas emissions in China. Basins which may provide storage sites for captured CO2 in North China are characterized by large sedimentary thicknesses and several sets of reservoir‐caprock strata. Some oil fields are nearing depletion and a sub‐set of these are potentially suitable for CO2 enhanced oil recovery (EOR) and CCS demonstration but all these still require detailed geological characterization. The short distance between the high concentration CO2 sources and potential storage sites should reduce transport costs and complications. The authors believe these high purity sources coupled with EOR or aquifer storage could offer China an opportunity to lead development in this globally beneficial CCS option. © 2013 Society of Chemical Industry and John Wiley & Sons, Ltd
Oxyfuel CFBC: status and anticipated development
Authors: Anthony E.J.(Ben)
Published: March 2013

Many technologies are now being explored to permit the combustion of fossil fuels while achieving CO2 capture in a state suitable for compression, transporting, and sequestration. Among the chief contenders are processes in which the fuel is first decarbonized, usually by gasification, followed by the use of a shift reaction to produce pure H2; post‐combustion capture, in which the CO2 is removed from the flue gases either at high temperatures (e.g. carbonate or Ca looping) or at near‐ambient temperatures (e.g. amine scrubbing); chemical looping in which the fuel is converted in the presence of a solid oxide carrier, thus producing a stream of gas consisting primarily of CO2 and H2O; and finally, oxyfuel combustion in which the fuel is burned in a stream of pure, or nearly pure, oxygen. The latter technology is already being investigated for application with pulverized fuel or coal, but more recently, the possibility of using oxyfuel combustion with circulating fluidized beds has been receiving increasing attention. There is already a 30 MWth demonstration unit operating in Spain, with plans to build a 300 MWe plant. This perspective describes the current status of oxyfuel research and development. © 2013 Society of Chemical Industry and John Wiley & Sons, Ltd
Height‐dependent transition from 3‐D to 2‐D turbulence in the hurricane boundary layer
Authors: Byrne David , Zhang Jun A.
Published: March 2013

Here we show, from in situ aircraft measurements in the hurricane boundary layer, a height‐dependent transition of the flow from 3‐D to 2‐D turbulence. This marks a fundamental change in the energy dynamics of the hurricane boundary layer due to the fact that in 3‐D, energy flows downscale from larger to smaller scales, whereas in 2‐D, it flows upscale, from smaller to larger scales. These results represent the first measurement of the 2‐D upscale energy flux in the atmosphere and also the first to characterize the transition from 3‐D to 2‐D. It is shown that the large‐scale parent vortex may gain energy directly from small scales in tropical cyclones.
Tropical coral reef habitat in a geoengineered, high‐CO2 world
Authors: Couce E. , Irvine P. J. , Gregoire L. J. , Ridgwell A. , Hendy E. J.
Published: March 2013

Continued anthropogenic CO2 emissions are expected to impact tropical coral reefs by further raising sea surface temperatures (SST) and intensifying ocean acidification (OA). Although geoengineering by means of solar radiation management (SRM) may mitigate temperature increases, OA will persist, raising important questions regarding the impact of different stressor combinations. We apply statistical Bioclimatic Envelope Models to project changes in shallow water tropical coral reef habitat as a single niche (without resolving biodiversity or community composition) under various representative concentration pathway and SRM scenarios, until 2070. We predict substantial reductions in habitat suitability centered on the Indo‐Pacific Warm Pool under net anthropogenic radiative forcing of ≥3.0 W/m2. The near‐term dominant risk to coral reefs is increasing SSTs; below 3 W/m2 reasonably favorable conditions are maintained, even when achieved by SRM with persisting OA. “Optimal” mitigation occurs at 1.5 W/m2 because tropical SSTs overcool in a fully geoengineered (i.e., preindustrial global mean temperature) world.
A new constraint on global air‐sea CO2 fluxes using bottle carbon data
Authors: Sasse Tristan P. , McNeil Ben I. , Abramowitz Gab
Published: March 2013

We develop a new observationally derived monthly ocean surface climatology for the partial pressure of CO2 (pCO2) that allows an independent data‐based constraint on contemporary air‐sea CO2 fluxes. Our approach uses a neural network, trained on ~17,800 bottle‐derived measurements of pCO2, to diagnose monthly pCO2 levels from standard ocean hydrographic data. Although the pattern of contemporary air‐sea CO2 fluxes is generally consistent with the independent underway pCO2 data network, we find a strong shift in the magnitude of oceanic sources and sinks of CO2. In particular, we find a contemporary Southern Hemisphere oceanic CO2 uptake of 0.93 PgC/year, driven by a prominent CO2 sink in the subpolar region (25°S–60°S), that is five times the magnitude of the Northern Hemisphere oceanic sink (0.18 PgC/year). Globally, our results suggest a net open‐ocean CO2 sink of 1.55 ± 0.32 PgC/year for the nominal year of 2000.
Determination of rock acoustic properties at low frequency: A differential acoustical resonance spectroscopy device and its estimation technique
Authors: Zhao Jianguo , Tang Genyang , Deng Jixin , Tong Xiaolong , Wang Shangxu
Published: March 2013

A laboratory device, Differential Acoustic Resonance Spectroscopy (DARS), has been developed to investigate the acoustic properties of rock materials below 1 KHz. The device is based on analyzing shifts of resonance frequency of a cavity perturbed by the presence of a small sample. Numerical and experimental studies have previously shown that this technique can be used to estimate the compressibility of samples. In this study, we adopt a nonlinear least‐squares whole‐curve‐fitting inversion approach, which for the first time allows estimation of both the compressibility and density of rock samples. In comparison to previous estimation techniques, this inversion method provides more reliable estimation of rock acoustic properties. This research proves that the DARS laboratory device, in conjunction with the calibration technique proposed herein, is a useful tool to estimate the properties of small rock samples. In addition, the simultaneous estimation of compressibility and density can potentially provide information on porosity and, by extension, a link between porosity and acoustic modulus at low frequency.
P‐Dodecylbenzenesulfonic Acid: A Highly Efficient Catalyst for One‐Pot Synthesis of α‐Aminophosphonates in Aqueous Media
Authors: Movassagh Barahman , Alapour Saba
Published: March 2013

A highly efficient one‐pot three‐component reaction of aldehydes or ketones, amines, and trimethyl or triethyl phosphite catalyzed by p‐dodecylbenzensulfonic acid is developed for the synthesis of α‐aminophosphonates at room temperature in water. © 2013 Wiley Periodicals, Inc. Heteroatom Chem 24:174–178, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/hc.21079
Iridoids from the Roots of Valeriana jatamansi
Authors: Li Yuan‐Dan , Wu Zhao‐Yuan , Li Hong‐Mei , Li Hai‐Zhou , Li Rong‐Tao
Published: March 2013

Three new iridoids, jatamanins N–P (1–3), along with the seven known iridiods 4–10, were isolated from the roots of Valeriana jatamansi. Compound 1 is an unusual iridoid bearing two epoxy bridges between C(3) and C(6) and between C(1) and C(10), forming a unique cage‐like rigid skeleton. The structures of the new compounds were assigned on the basis of spectroscopic methods.
Temperature‐Dependent Product Selectivity in the VilsmeierHaack Reaction on Bis(phenylhydrazones) of Bis(aroylmethyl) Sulfides (=1,1′‐[Thiobis(methylene)]bis[arylmethanone] Bis(2‐phenylhydrazones)): Synthesis of 3‐Aroylindoles (=Aryl(1H‐indol‐3‐yl)methanones)
Authors: Paul Nidhin , Muthusubramanian Shanmugam
Published: March 2013

The bis(phenylhydrazone) of substituted diphenacyl sulfides (=1,1′‐[thiobis(methylene)]bis[arylmethanone] bis(2‐phenylhydrazones)) 1 underwent a tandem sequence of reactions upon treatment with Vilsmeier reagent, ultimately yielding 3‐aroylindoles (=aryl(1H‐indol‐3‐yl)methanones) 3 (Scheme 1 and Table 1). The reaction seems to be product selective depending upon the reaction temperature.