bluuebunny/crossref_metadata_2025 huggingface dataset:
Trigonal‐Bipyramidal and Square‐Pyramidal ChromiumManganese Chalcogenide Clusters, [E2CrMn2(CO)n]2− (E=S, Se, Te; n=9, 10): Synthesis, Electrochemistry, UV/Vis Absorption, and Computational Studies
Authors: Shieh Minghuey , Yu Chun‐Hsien , Chu Yen‐Yi , Guo Yu‐Wen , Huang Chung‐Yi , Hsing Kai‐Jieah , Chen Pei‐Chi , Lee Chung‐Feng
Published: February 2013

The reactions of E powder (E=S, Se) with a mixture of Cr(CO)6 and Mn2(CO)10 in concentrated solutions of KOH/MeOH produced two new mixed CrMncarbonyl clusters, [E2CrMn2(CO)9]2− (E=S, 1; Se, 2). Clusters 1 and 2 were isostructural with one another and each displayed a trigonal‐bipyramidal structure, with the CrMn2 triangle axially capped by two μ3‐E atoms. The analogous telluride cluster, [Te2CrMn2(CO)9]2− (3), was obtained from the ring‐closure of Te2Mn2 ring complex [Te2Mn2Cr2(CO)18]2− (4). Upon bubbling with CO, clusters 2 and 3 were readily converted into square‐pyramidal clusters, [E2CrMn2(CO)10]2− (E=Se, 5; Te, 6), accompanied with the cleavage of one CrMn bond. According to SQUID analysis, cluster 6 was paramagnetic, with S=1 at room temperature; however, the Se analogue (5) was spectroscopically proposed to be diamagnetic, as verified by TD‐DFT calculations. Cluster 6 could be further carbonylated, with cleavage of the MnMn bond to produce a new arachno‐cluster, [Te2CrMn2(CO)11]2− (7). The formation and structural isomers, as well as electrochemistry and UV/Vis absorption, of these clusters were also elucidated by DFT calculations.
Novel Thiazolo[5,4‐d]thiazole‐Based Organic Dyes for Quasi‐Solid‐State Dye‐Sensitized Solar Cells
Authors: Zhang Weiyi , Feng Quanyou , Wang Zhong‐Sheng , Zhou Gang
Published: February 2013

A series of novel metal‐free organic dyes containing the thiazolo[5,4‐d]thiazole moiety were designed and synthesized for quasi‐solid‐state dye‐sensitized solar cells (DSSCs). Different alkoxy chains were introduced into the electron donor part of the dye molecules for comparison. The optical, electrochemical, and photovoltaic properties for all sensitizers were systematically investigated. It was found that the sensitizers with the different alkoxy groups have similar photophysical and electrochemical properties, such as absorbance and energy levels, owing to their close chemical structures. However, the quasi‐solid‐state DSSCs based on the resulting sensitizers exhibit different performance parameters. The quasi‐solid‐state DSSC based on sensitizer FNE74 with two octyloxy chains possessed the highest solar energy conversion efficiency of 5.10 % under standard AM 1.5G sunlight illumination without the use of coadsorbant agents.
Parameter estimation of an agent‐based stock price model
Authors: Çağlar Mine , Bahtiyar Nihal , Altıntaş İpek
Published: February 2013

The influence of the behavior and strategies of traders on stock price formation has attracted much interest. It is assumed that there is a positive correlation between the total net demand and the price change. A buy order is expected to increase the price, whereas a sell order is assumed to decrease it. We perform data analysis based on a recently proposed stochastic model for stock prices. The model involves long‐range dependence, self‐similarity, and no arbitrage principle, as observed in real data. The arrival times of orders, their quantity, and their duration are created by a Poisson random measure. The aggregation of the effect of all orders based on these parameters yields the log‐price process. By scaling the parameters, a fractional Brownian motion or a stable Levy process can be obtained in the limit. In this paper, our aim is twofold; first, to devise statistical methodology to estimate the model parameters with an application on high‐frequency price data, and second, to validate the model by simulations with the estimated parameters. We find that the statistical properties of agent level behavior are reflected on the stock price, and can affect the entire process. Moreover, the price model is suitable for prediction through simulations when the parameters are estimated from real data. The methods developed in the present paper can be applied to frequently traded stocks in general. Copyright © 2013 John Wiley & Sons, Ltd.
Cancer Risks in Parents Who had a Child with a Congenital Malformation
Authors: Sun Yuelian , Overvad Kim , Zhou Wei Jin , Zhu Jin Liang , Olsen Jørn
Published: February 2013

Cancer risk in parents may be related to congenital malformations (CMs) in their children if they share genetic susceptibility or environmental exposure that may be teratogenic and carcinogenic. We conducted a population‐based cohort study based on Danish register data. We identified 795,607 mothers and 781,424 fathers who had all their children between 1977 and 2007 in Denmark. Information on CM was obtained from the Danish Hospital Registry and information on cancer was obtained from the Danish Cancer Registry. Parents were followed from the birth of their first child until the diagnosis of cancer, death, emigration, or December 31, 2007. We used Cox regression models to estimate hazard ratios (HRs) for cancer including cancer in specific organs in mothers and fathers. Overall, 75,701 (9.5%) mothers and 72,724 (9.3%) fathers had at least one child diagnosed with CMs within the first year of life. Neither mothers (HR = 1.04; 95% CI: 0.99–1.04) nor fathers (HR = 1.03; 95% CI: 0.98–1.09) who had a child with a CM had a higher overall risk of cancer. Mothers (HR = 0.76, 95% CI: 0.58–1.00) or fathers (HR = 0.89, 95% CI: 0.66–1.19) who had a child with a chromosomal malformation had a lower overall cancer risk. The findings also showed a higher risk for some specific types of cancer in parents who had children with a CM in the specific system. Some, or perhaps all, of these findings may be due to chance caused by multiple comparisons. We present all results on paper or online to provide clues for further research and to avoid publication bias.
Genomically and biochemically accurate metabolic reconstruction of Methanosarcina barkeri Fusaro, iMG746
Authors: Gonnerman Matthew C. , Benedict Matthew N. , Feist Adam M. , Metcalf William W. , Price Nathan D.
Published: February 2013

Methanosarcina barkeri is an Archaeon that produces methane anaerobically as the primary byproduct of its metabolism. M. barkeri can utilize several substrates for ATP and biomass production including methanol, acetate, methyl amines, and a combination of hydrogen and carbon dioxide. In 2006, a metabolic reconstruction of M. barkeri, iAF692, was generated based on a draft genome annotation. The iAF692 reconstruction enabled the first genome‐Scale simulations for Archaea. Since the publication of the first metabolic reconstruction of M. barkeri, additional genomic, biochemical, and phenotypic data have clarified several metabolic pathways. We have used this newly available data to improve the M. barkeri metabolic reconstruction. Modeling simulations using the updated model, iMG746, have led to increased accuracy in predicting gene knockout phenotypes and simulations of batch growth behavior. We used the model to examine knockout lethality data and make predictions about metabolic regulation under different growth conditions. Thus, the updated metabolic reconstruction of M. barkeri metabolism is a useful tool for predicting cellular behavior, studying the methanogenic lifestyle, guiding experimental studies, and making predictions relevant to metabolic engineering applications.
Flux‐coupled genes and their use in metabolic flux analysis
Authors: Kim Hyun Uk , Kim Won Jun , Lee Sang Yup
Published: February 2013

As large volumes of omics data have become available, systems biology is playing increasingly important roles in elucidating new biological phenomena, especially through genome‐scale metabolic network modeling and simulation. Much effort has been exerted on integrating omics data with metabolic flux simulation, but further development is necessary for more accurate flux estimation. To move one step forward, we adopted the concept of flux‐coupled genes (FCGs), which show that their expression transition patterns upon perturbations are correlated with their corresponding flux values, as additional constraints in metabolic flux analysis. It was found that gnd, pfkB, rpe, sdhB, sdhD, sucA, and zwf genes, mostly associated with pentose phosphate pathway and TCA cycle, were the most consistent FCGs in Escherichia coli based on its transcriptome and 13C‐flux data obtained from the chemostat cultivation at five different dilution rates. Consequently, constraints‐based flux analyses with FCGs as additional constraints were conducted for the seven single‐gene knockout mutants, compared with those obtained without using FCGs. This strategy of constraining the metabolic flux analysis with FCGs is expected to be useful due to the relative ease in obtaining transcriptional information in the functional genomics era.
Aqueous biphasic systems composed of ionic liquids and sodium carbonate as enhanced routes for the extraction of tetracycline
Authors: Marques Carlos F. C. , Mourão Teresa , Neves Catarina M. S. S. , Lima Álvaro S. , Boal‐Palheiros Isabel , Coutinho João A. P. , Freire Mara G.
Published: February 2013

Aqueous biphasic systems (ABS) using ionic liquids (ILs) offer an alternative approach for the extraction, recovery, and purification of biomolecules through their partitioning between two aqueous liquid phases. In this work, the ability of a wide range of ILs to form ABS with aqueous solutions of Na2CO3 was evaluated. The ABS formed by IL + water + Na2CO3 were determined at 25°C, and the respective solubility curves, tie‐lines, and tie‐line lengths are reported. The studied ILs share the common chloride anion, allowing the IL cation core, the cation isomerism, the presence of functionalized groups, and alkyl side chain length effects to be evaluated. An increase in the cation side alkyl chain length leads to a higher ability for liquid–liquid demixing whereas different positional isomers and the presence of an allyl group have no major influence in the phase diagrams behavior. Quaternary phosphonium‐ and ammonium‐based fluids are more able to form an ABS when compared with imidazolium‐, pyridinium‐, pyrrolidinium‐, and piperidium‐based ILs. Moreover, the presence of an aromatic cation core has no major contribution to the formation of ABS when compared to the respective nonaromatic counterparts. Finally, to appraise on the systems applicability in downstream processing, selected systems were used for the partitioning of tetracyclines (neutral and salt forms) — a class of antibiotics produced by bacteria fermentation. Single‐step extraction efficiencies for the IL‐rich phase were always higher than 99% and confirm the great potential of ILs to be applied in the biotechnological field. © 2013 American Institute of Chemical Engineers Biotechnol. Prog., 29:645–654, 2013
Two Antiproliferative Triterpene Saponins from Nematostylis anthophylla from the Highlands of Central Madagascar
Authors: Dai Yumin , Harinantenaina Liva , Brodie Peggy J. , Birkinshaw Chris , Randrianaivo Richard , Applequist Wendy , Ratsimbason Michel , Rasamison Vincent E. , Shen Yongchun , TenDyke Karen , Kingston David G. I.
Published: February 2013

Investigation of the endemic Madagascan plant Nematostylis anthophylla (Rubiaceae) for antiproliferative activity against the A2780 ovarian cancer cell line led to the isolation of the known triterpene saponin randianin (1), and the two new bioactive triterpene saponins 2″‐O‐acetylrandianin (2) and 6″‐O‐acetylrandianin (3). The structures of the two new compounds were elucidated based on analysis of their 1D‐ and 2D‐NMR spectra, and mass spectrometric data. The three isolated triterpene saponins displayed moderate but selective antiproliferative activities, with IC50 values of 1.2, 1.7, and 2.2 μM, respectively, against the A2780 ovarian cancer, but only weak inhibitions of the proliferation of A2058 melanoma and the H522 lung cancer cell lines.
Chemical Constituents from a Soil‐Derived Actinomycete, Actinomadura miaoliensis BCRC 16873, and Their Inhibitory Activities on Lipopolysaccharide‐Induced Tumor Necrosis Factor Production
Authors: Tseng Min , Su Yung‐Shun , Cheng Ming‐Jen , Liu Ta‐Wei , Chen Ih‐Sheng , Wu Ming‐Der , Chang Hsun‐Shuo , Yuan Gwo‐Fang
Published: February 2013

An investigation on the secondary metabolites from the BuOH extract of the fermentation broth of the thermotolerant polyester‐degrading actinomycete Actinomadura miaoliensis BCRC 16873 was carried out. One previously undescribed α‐pyrone (=pyran‐2‐one) derivative, designated as miaolienone (1), and a new butanolide, miaolinolide (2), together with 13 known compounds, 3–15, were obtained. Their structures were established on the basis of extensive 1D‐ and 2D‐NMR analyses in combination with HR‐MS experiments. In addition, the isolated compounds 1–15 were evaluated for the inhibitory effects of the isolates on the production of tumor necrosis factor (TNF‐α) induced by lipopolysaccharide (LPS). Among the isolates, 1 and 2 significantly inhibited TNF‐α production in U937 cells in vitro, and the IC50 values were 0.59 and 0.76 μM, respectively. Compounds 3–5 displayed moderate inhibitory activities on LPS‐induced TNF‐α production.
Melanogenesis‐Inhibitory Activity of Aromatic Glycosides from the Stem Bark of Acer buergerianum
Authors: Akihisa Toshihiro , Orido Masashi , Akazawa Hiroyuki , Takahashi Akitomo , Yamamoto Ayako , Ogihara Eri , Fukatsu Makoto
Published: February 2013

A new benzyl glucoside, 3‐O‐demethylnikoenoside (1), along with eleven known compounds, including seven aromatic glycosides, 2–8, three lignans, 9–11, and one cyclitol, 12, were isolated from the BuOH‐soluble fraction of a MeOH extract of Acer buergerianum stem bark. The structures of the new compound were elucidated on the basis of extensive spectroscopic analyses and comparison with literature. Upon evaluation of compounds 1–12 on melanogenesis in B16 melanoma cells induced with α‐melanocyte‐stimulating hormone (α‐MSH), three compounds, i.e., hovetrichoside B (8), pinoresinol 4‐O‐β‐D‐glucopyranoside (9), and pinoresinol 4‐O‐β‐D‐apiofuranosyl‐(1→2)‐β‐D‐glucopyranoside (10), have been found to exhibit inhibitory effects with 41–49% melanin content compared to the control at 100 μM and low cytotoxicity to the cells (81–92% cell viability at 100 μM). Western blot analysis showed that compound 8 reduced the protein levels of MITF (=microphtalmia‐associated transcription factor) and tyrosinase, in a concentration‐dependent manner, suggesting that 8 inhibits melanogenesis in α‐MSH‐stimulated B16 melanoma cells by, at least in part, inhibiting the expression of MITF, followed by decreasing the expression of tyrosinase. On the other hand, upon Western blotting, compound 9 was found to reduce the protein levels of tyrosinase and TRP‐2, while it increased MITF and TRP‐1 (=tyrosine‐related protein 1), in a concentration‐dependent manner, indicating that 9 inhibits melanogenesis in α‐MSH‐stimulated B16 melanoma cells by, at least in part, inhibiting the expression of tyrosinase and TRP‐2.
Stenting the arterial duct in neonates and infants with congenital heart disease and duct‐dependent pulmonary blood flow: A multicenter experience of an evolving therapy over 18 years
Authors: Udink ten Cate Floris E.A. , Sreeram Narayanswami , Hamza Hala , Agha Hala , Rosenthal Eric , Qureshi Shakeel A.
Published: February 2013

Objectives

The primary aim of this multi‐institutional study was to describe our 18‐year experience of ductal stenting (DS) in infants with a duct‐dependent pulmonary circulation. The secondary aim sought to identify a subgroup of patients who may benefit the most using this evolving technique.

Background

No study has examined the extraordinary evolution of this promising therapy over the last two decades.

Methods

Between 1991 and 2009, 65 neonates and infants (39 male, 60%) underwent cardiac catheterization for DS in 3 participating centres. Patients were divided according to whether DS was attempted between 1991–2000 (Group 1, n = 20) or between 2001–2009 (Group 2, n = 45).

Results

DS was successful in 52/65 (80%) patients. DS outcome was associated with ductal morphology and cardiac diagnosis. DS failed more often in patients with univentricular physiology and tortuous duct morphology (p < 0.001). Most patients undergoing DS in Group 2 had pulmonary atresia with intact ventricular septum (PAIVS) (p < 0.001). DS was successful in 94% of these patients. Groups differed significantly in diameter and length of first implanted stent (p < 0.001), implanting additional stent (p < 0.001), and occurrence of complications (p = 0.033). Freedom from re‐intervention for the 52 patients was 92.3%. No procedure‐related mortality occurred.

Conclusions

The technical aspects and clinical application of percutaneous DS has changed in the last two decades. DS has become a practical and safe therapy in a subgroup of neonates with ductal‐dependent pulmonary blood flow.© 2013 Wiley Periodicals, Inc.
Three‐dimensional rotational X‐ray acquisition technique is reducing patients' cancer risk in coronary angiography
Authors: Eloot Liesbeth , Bacher Klaus , Steenbeke Femke , Drieghe Benny , Gheeraert Peter , Taeymans Yves , Thierens Hubert
Published: February 2013

Objectives

The purpose of this study was to assess patient‐specific organ doses and cancer risk with 3D‐rotational acquisitions versus the current standard of multiple single‐plane coronary angiography (CA).

Background

Catheter‐based CA remains one of the most commonly performed diagnostic invasive procedures delivering a relatively high radiation dose to the patient. With the introduction of flat‐panel technology, three‐dimensional rotational angiography became an alternative for the conventional two‐dimensional angiography. However, limited information is available on the difference in patient radiation exposure with both acquisition techniques.

Methods

Eighty adult patients (45 males, age 38–93 years) were randomly assigned to the rotational or standard angiography group. Exposure parameters were registered and skin dose distribution was measured during the procedure. Patient‐specific organ doses and related cancer risks were assessed with dedicated software.

Results

Rotational angiograms were associated with 33% lower KAP‐values (decrease from 49.99 Gycm2 to 33.37 Gycm2, P < 0.001). A significant (P < 0.001) lower peak skin dose was measured with rotational acquisitions (80 mGy, median) versus planar imaging (172 mGy, median). Moreover, the skin dose was smoothed over the whole chest of the patient. Contrast medium consumption decreased from 104 mL to 73 mL (P < 0.001) with the use of 3D‐imaging. The reduction in radiation exposure resulted in a corresponding decrease of organ doses. The latter contributed to an overall cancer risk reduction of 21% for males and 50% for females.

Conclusions

The current study demonstrates that in CA radiation risk reduction is feasible by using a rotational acquisition technique.© 2013 Wiley Periodicals, Inc.
AgBr Nanocrystals from Plates to Cubes and Their Photocatalytic Properties
Authors: Wang Hua , Liu Yang , Hu Pengfei , He Liang , Li Jinghong , Guo Lin
Published: February 2013

AgBr nanocrystals, evolving from plates through truncated cubes and finally to regular cubes, corresponding to a progressive shrinkage of exposed {1 1 1} facets and enlargement of exposed {1 0 0} facets, were successfully prepared by facile ion‐exchange reactions under the synergistic effects of polyvinylpyrrolidone and NH3⋅ H2O. An investigation of the growth mechanism revealed that polyvinylpyrrolidone can selectively adsorb on the {1 1 1} facets of AgBr nanocrystals, whereas NH3⋅H2O not only forms a [Ag(NH3)2]+ complex that slows the rates of ion‐exchange reactions, but may also prefer to adsorb on {1 0 0} facets. Studies of their photocatalytic properties showed that the as‐prepared AgBr nanocrystals exhibited facet‐dependent photocatalytic properties. The {1 1 1}‐dominated AgBr nanoplates exhibited the highest photocatalytic activities, and the photodegradation rate of methyl orange dyes over them was 3 times faster than over AgBr nanocubes that expose {1 0 0} facets. Surface atomic models and DFT calculations indicate that the {1 1 1} facets have more dangling bonds and a higher surface energy than the {1 0 0} facets, which substantiate the facet‐dependent photocatalytic properties. Therefore, our work not only provides a novel method to prepare regular AgBr nanocrystals, but also demonstrates that the shape and exposed facets have important influence on their photocatalytic activities.
Proton Shuttle Mechanism in the Transition State of Lipase‐Catalyzed N‐Acylation of Amino Alcohols
Authors: Syrén Per‐Olof , Le Joubioux Florian , Ben Henda Yesmine , Maugard Thierry , Hult Karl , Graber Marianne
Published: February 2013

An increased reaction rate for lipase‐catalyzed N‐acylation of amino alcohols relative to that of monofunctionalized amines can be explained by a hydrogen shuttling mechanism that avoids nitrogen inversion in the transition state. The mechanism does not involve acyl migration from an ester intermediate that would be formed first, an explanation that permeates the literature. Our suggested reaction mechanism is dependent on the preference of amino alcohols to form intramolecular hydrogen bonds and the capability of the enzyme to accommodate and exploit the specific hydrogen bonding pattern provided by the ligand during catalysis. Our proposed proton shuttle mechanism involves the transfer of two protons in the transition state concomitant with a nucleophilic attack on the acyl enzyme and provides an explanation for the high reaction rate and chemoselectivity for lipase‐catalyzed N‐acylation of amino alcohols. Moreover, the proton shuttle mechanism explains the increased reaction rate for the enzyme‐catalyzed N‐acylation of diamines and of methoxy‐2‐propylamine, for which O‐ to N‐acyl migration is impossible. A linear free‐energy relationship analysis based on the experimental results showed that all of our investigated difunctionalized amine substrates afforded a substrate‐assisted rate acceleration of the N‐acylation by the same reaction mechanism. Furthermore, the results of the analysis were consistent with partial proton transfer in the rate‐limiting transition state, which further supports our suggested proton shuttle mechanism.
Enhancing Photoactivity of TiO2(B)/Anatase Core–Shell Nanofibers by Selectively Doping Cerium Ions into the TiO2(B) Core
Authors: Yang Dongjiang , Zhao Jian , Liu Hongwei , Zheng Zhanfeng , Adebajo Moses O. , Wang Hongxia , Liu Xiaotang , Zhang Hongjie , Zhao Jin‐cai , Bell John , Zhu Huaiyong
Published: February 2013

Cerium ions (Ce3+) can be selectively doped into the TiO2(B) core of TiO2(B)/anatase core–shell nanofibers by means of a simple one‐pot hydrothermal treatment of a starting material of hydrogen trititanate (H2Ti3O7) nanofibers. These Ce3+ ions (≈0.202 nm) are located on the (110) lattice planes of the TiO2(B) core in tunnels (width≈0.297 nm). The introduction of Ce3+ ions reduces the defects of the TiO2(B) core by inhibiting the faster growth of (110) lattice planes. More importantly, the redox potential of the Ce3+/Ce4+ couple (E°(Ce3+/Ce4+)=1.715 V versus the normal hydrogen electrode) is more negative than the valence band of TiO2(B). Therefore, once the Ce3+‐doped nanofibers are irradiated by UV light, the doped Ce3+ ions—in close vicinity to the interface between the TiO2(B) core and anatase nanoshell—can efficiently trap the photogenerated holes. This facilitates the migration of holes from the anatase shell and leaves more photogenerated electrons in the anatase nanoshell, which results in a highly efficient separation of photogenerated charges in the anatase nanoshell. Hence, this enhanced charge‐separation mechanism accelerates dye degradation and alcohol oxidation processes. The one‐pot treatment doping strategy is also used to selectively dope other metal ions with variable oxidation states such as Co2+/3+ and Cu+/2+ ions. The doping substantially improves the photocatalytic activity of the mixed‐phase nanofibers. In contrast, the doping of ions with an invariable oxidation state, such as Zn2+, Ca2+, or Mg2+, does not enhance the photoactivity of the mixed‐phase nanofibers as the ions could not trap the photogenerated holes.
Design of Stable β‐Sheet‐Based Cyclic Peptide Assemblies Assisted by Metal Coordination: Selective Homo‐ and Heterodimer Formation
Authors: Panciera Michele , Amorín Manuel , Castedo Luis , Granja Juan R.
Published: February 2013

Metal‐directed supramolecular construction represents one of the most powerful tools to prepare a large variety of structures and functions. The ability of metals to organize different numbers and types of ligands with a variety of geometries (linear, trigonal, octahedral, etc.) expands the supramolecular synthetic architecture. We describe here the precise construction of homo‐ and heterodimeric cyclic peptide entities through coordination of a metal (Pd, Au) and to β‐sheet‐type hydrogen‐bonding interactions. The selective coordination properties of the appropriate metal allow control over the cross‐strand interaction between the two‐peptide strands.
Aqueous‐Phase Synthesis of Single‐Crystal Pd Seeds 3 nm in Diameter and Their Use for the Growth of Pd Nanocrystals with Different Shapes
Authors: Zhu Cun , Zeng Jie , Lu Ping , Liu Jingyue , Gu Zhongze , Xia Younan
Published: February 2013

This article describes an aqueous method for the synthesis of Pd seeds with a single‐crystal structure and a uniform diameter of 3 nm and their use for the growth of Pd nanocrystals with a variety of shapes. We have also investigated the effects of a number of parameters, including the temperature, reducing power of the reductant, and capping agent on the reduction rate of a Pd precursor, and thus the final size, size distribution, and morphology of the Pd seeds. By taking advantage of the coordination effect of Br− ions with Pd2+ ions and their selective adsorption on the Pd(100) surface, Pd nanocrystals with a number of distinct shapes could be conveniently produced by varying the concentration of KBr added into the growth solution. This work provides a general and facile method for the green synthesis of Pd nanocrystals with controlled shapes, especially for the preparation of Pd nanocrystals with sizes in the sub‐10 nm regime.
Asararenes—A Family of Large Aromatic Macrocycles
Authors: Schneebeli Severin T. , Cheng Chuyang , Hartlieb Karel J. , Strutt Nathan L. , Sarjeant Amy A. , Stern Charlotte L. , Stoddart J. Fraser
Published: February 2013

We announce the establishment of a new family of macrocycles—the asararenes, which are based on para‐methylene linked “asarol methyl ether” (1,2,4,5‐tetramethoxybenzene) units. Macrocycles with 6–12 aromatic units have been synthesized and isolated in a single step from asarol methyl ether and paraformaldehyde. Even larger rings, with up to 15 asarol methyl ether units, have been observed by high‐resolution mass spectrometry. Single‐crystal X‐ray structures of asar[6]‐, asar[7]‐, asar[8]‐, asar[9]‐, asar[10]‐ and asar[11]arene highlight the diverse structural features of this family of macrocycles. While the cavities of the asar[6–8]arene macrocycles are mostly filled with methoxyl groups, the asar[9]‐ and asar[10]arene rings contain accessible cavities and self‐assemble into infinite channels filled with solvent molecules in the solid state. These solid‐state structures highlight the potential of this family of macrocycles for a wide range of potential applications.
Theoretical Insights into the Nature of Halogen Bonding in Prereactive Complexes
Authors: Hill J. Grant , Hu Xiaojun
Published: February 2013

Benchmark quality geometries and interaction energies for the prereactive halogen‐bonded complexes of dihalogens and ammonia, including hypothetical astatine containing dihalogens, have been produced via explicitly correlated coupled cluster methods. The application of local electron correlation partitioning reveals dispersion, electrostatics and ionic substitutions all contribute significantly to the interaction energy, with a linear relationship between the ionic substitutions and the degree of charge transfer. Potential energy curves for H3N⋅⋅⋅ClF show that as the relative orientations of the two subunits are manipulated appreciable interactions can be found at considerably angular displaced geometries, signifying lower directionality in halogen bonding than previously supposed.
Enhancement of Carbon Dioxide Capture by Amine‐Functionalized Multi‐Walled Carbon Nanotube
Authors: Khalili Soodabeh , Ghoreyshi Ali Asghar , Jahanshahi Mohsen , Pirzadeh Kasra
Published: February 2013

In this study, crude multi‐walled carbon nanotubes (MWCNT) was functionalized by a two‐step process; first using strong mixed acids (H2SO4/HNO3) and then treatment with 1,3‐phenylenediamine (mPDA). The equilibrium adsorption of CO2 on pristine MWCNT and amine functionalized MWCNT (MWCNT‐NH2) were investigated. Experiments were preformed via application of volumetric method in a dual sorption vessel at temperature range of 298–318 K and pressures up to 40 bars. The results obtained indicated that the equilibrium uptake of CO2 increased after functionalizing of MWCNT. The increase in CO2 capture by MWCNT‐NH2 was attributed to the existence of great affinity between CO2 molecules and amine sites on this adsorbent at low pressures. The experimental data were analyzed by means of Freundlich and Langmuir adsorption isotherm models. The data obtained revealed a fast kinetics for the adsorption of CO2 in which most of adsorption occurred at initial period of adsorption experiments. This renders MWCNT as a suitable adsorbent for practical applications. Values of isosteric heat of adsorption were evaluated based on Clausius–Clapeyron equation. The results demonstrated that both chemisorption and physisorption played important role in CO2 adsorption on MWCNT‐NH2, whereas the physisorption process was dominant for CO2 adsorption on MWCNT.
Direct Fluorination of Cyclic Carbonates and closo‐K2[B12H12] in a Slug‐Flow Ministructured Reactor
Authors: Hill Mathias , Baron Patrick , Cobry Keith , Goll Sascha K. , Lang Philipp , Knapp Carsten , Scherer Harald , Woias Peter , Zhang Pengcheng , Krossing Ingo
Published: February 2013

A novel minireactor for direct fluorination of organic and inorganic substances was tested. The reactor consists of nickel‐coated copper blocks with mechanically machined 1 mm channels and is equipped with an active cooling system. The direct fluorination of ethylene carbonate and propylene carbonate is described. For the fluorinated propylene carbonate, the NMR data of various fluorinated isomers were determined. The Gibbs reaction energies for the direct fluorination of ethylene and propylene carbonate were calculated at the reliable G3 level of theory. The excellent decomposition stability of the cyclic carbonates against high fluorine and HF concentrations also qualifies them as good solvents for direct fluorination processes, especially for ionic substrates. In this respect, the direct fluorination of the inorganic salt closo‐K2[B12H12] in cyclic carbonates is presented.
BaSnO3 Perovskite Nanoparticles for High Efficiency Dye‐Sensitized Solar Cells
Authors: Kim Dong Wook , Shin Seong Sik , Lee Sangwook , Cho In Sun , Kim Dong Hoe , Lee Chan Woo , Jung Hyun Suk , Hong Kug Sun
Published: February 2013

The synthesis of highly crystalline perovskite BaSnO3 nanoparticles for use as photoanode materials in dye‐sensitized solar cells (DSSCs) is reported, and the photovoltaic properties of DSSCs based on BaSnO3 nanoparticles (BaSnO3 cells) are demonstrated. The resulting DSSCs exhibit remarkably rapid charge collection and a DSSC fabricated with a BaSnO3 film thickness of 43 µm leads to a high energy conversion efficiency of 5.2 %, which is one of the highest reported for ternary oxide‐based DSSCs. More importantly, the BaSnO3 cells show superior charge collection in nanoparticle films compared to TiO2 cells and could offer a breakthrough in the efficiencies of DSSCs.
Neural correlates of intersensory processing in 5‐month‐old infants
Authors: Reynolds Greg D. , Bahrick Lorraine E. , Lickliter Robert , Guy Maggie W.
Published: February 2013

Two experiments assessing event‐related potentials in 5‐month‐old infants were conducted to examine neural correlates of attentional salience and efficiency of processing of a visual event (woman speaking) paired with redundant (synchronous) speech, nonredundant (asynchronous) speech, or no speech. In Experiment 1, the Nc component associated with attentional salience was greater in amplitude following synchronous audiovisual as compared with asynchronous audiovisual and unimodal visual presentations. A block design was utilized in Experiment 2 to examine efficiency of processing of a visual event. Only infants exposed to synchronous audiovisual speech demonstrated a significant reduction in amplitude of the late slow wave associated with successful stimulus processing and recognition memory from early to late blocks of trials. These findings indicate that events that provide intersensory redundancy are associated with enhanced neural responsiveness indicative of greater attentional salience and more efficient stimulus processing as compared with the same events when they provide no intersensory redundancy in 5‐month‐old infants. © 2013 Wiley Periodicals, Inc. © 2013Wiley Periodicals, Inc. Dev Psychobiol 56: 355–372, 2014.
Characterization of Lgr5‐positive epithelial cells in the murine thymus
Authors: Vroegindeweij Eric , van Mourik Irene , Cupedo Tom , Cornelissen Jan J.
Published: February 2013

Leucine‐rich repeat‐containing G protein‐coupled receptor (Lgr)5 is a marker for epithelial stem cells in the adult intestine of mice. Lgr5 transcripts have also been detected in the developing murine thymus, leading to speculation that Lgr5 is a marker for the long‐sought stem cell of the thymus. To address the nature of the Lgr5‐expressing thymic epithelial cells (TECs), we used Lgr5‐GFP reporter mice. We show that epithelial cells expressing Lgr5 protein are present in the fetal thymus during a specific developmental window yet are no longer detectable at birth. To analyze the function of the Lgr5 protein during thymus development, we generated Lgr5−/− mice. These experiments unequivocally show that thymus development is not perturbed in the absence of Lgr5, that all TEC subsets develop in Lgr5−/− mice and that T cells are produced in the expected ratios. Finally, by using an inducible lineage tracing system to track the progeny of Lgr5+ fetal TECs in vivo, we demonstrated that Lgr5+ fetal TECs have no detectable progeny in the later fetal thymus. In sum, we show that presence of the Lgr5 protein is not a prerequisite for proper thymus organogenesis.
Organic Chromophores Based on a Fused Bis‐Thiazole Core and Their Application in Dye‐Sensitized Solar Cells
Authors: Dessì Alessio , Barozzino Consiglio Gabriella , Calamante Massimo , Reginato Gianna , Mordini Alessandro , Peruzzini Maurizio , Taddei Maurizio , Sinicropi Adalgisa , Parisi Maria Laura , Fabrizi de Biani Fabrizia , Basosi Riccardo , Mori Riccardo , Spatola Michele , Bruzzi Mara , Zani Lorenzo
Published: February 2013

Four new D‐π‐A organic dyes incorporating either a thiazolo[5,4‐d]thiazole bicyclic system (TTZ1–2) or a benzo[1,2‐d:4,5‐d′]bisthiazole tricyclic unit (BBZ1–2) have been synthesized and fully characterized. The key steps of the synthesis include an efficient MW‐assisted preparation of the thiazolo[5,4‐d]thiazole core and selective functionalization of two different dihalothienyl derivatives through Suzuki coupling. All the compounds showed photo‐ and electrochemical properties compatible with their employment in dye‐sensitized solar cells. In addition, their electronic structure and transitions were investigated by means of TD‐DFT calculations. Dye‐sensitized solar cells fabricated with dye TTZ1 yielded an average power conversion efficiency corresponding to 43 and 60 % of the performances recorded under the same conditions for cells containing reference dyes N3 and D5, respectively. Efficiency measurements and electrochemical impedance spectroscopy (EIS) experiments indicated that use of chenodeoxycholic acid (CDCA) as a co‐adsorbent was beneficial to disrupt dye‐dye interactions and slow down recombination processes within the cells, thus allowing power conversion efficiencies up to 3.53 % to be obtained.
Urine of patients with early prostate cancer contains lower levels of light chain fragments of inter‐alpha‐trypsin inhibitor and saposin B but increased expression of an inter‐alpha‐trypsin inhibitor heavy chain 4 fragment
Authors: Jayapalan Jaime J. , Ng Keng L. , Shuib Adawiyah S. , Razack Azad H. A. , Hashim Onn H.
Published: February 2013

The present study was aimed at the identification of proteins that are differentially expressed in the urine of patients with prostate cancer (PCa), those with benign prostatic hyperplasia (BPH) and age‐matched healthy male control subjects. Using a combination of 2DE and MS/MS, significantly lower expression of urinary saposin B and two different fragments of inter‐alpha‐trypsin inhibitor light chain (ITIL) was demonstrated in the PCa patients compared to the controls. However, only one of the ITIL fragments was significantly different between the PCa and BPH patients. When image analysis was performed on urinary proteins that were transferred onto NC membranes and detected using a lectin that binds to O‐glycans, a truncated fragment of inter‐alpha‐trypsin inhibitor heavy chain 4 was the sole protein found to be significantly enhanced in the PCa patients compared to the controls. Together, these urinary peptide fragments might be useful complementary biomarkers to indicate PCa as well as to distinguish it from BPH, although further epidemiological evidence on the specificity and sensitivity of the protein candidates is required.
Study on the interrelated effects of capillary diameter, background electrolyte concentration, and flow rate in pressure assisted capillary electrophoresis with contactless conductivity detection
Authors: Mai Thanh Duc , Hauser Peter C.
Published: February 2013

A detailed study on the effect of the buffer concentration and the magnitude of the superimposed hydrodynamic flow on separation performance in CZE with contactless conductivity detection was carried out with capillaries of 10, 25, and 50 μm internal diameter. It was confirmed that capillaries of narrow internal diameters require higher buffer concentrations for best sensitivities. For all diameters it was found that electrodispersion was the most pronounced band‐broadening factor for relatively long residence times. For shorter times, Joule heating related band broadening appears to be the most significant factor, which means that best separation efficiencies are obtained with the narrowest capillaries. As detection limits are as good for capillaries of 10 μm internal diameters as for the other diameters when using contactless conductivity detection, these narrow capillaries are, therefore, generally of benefit when employing this detection technique. Hydrodyamic flow was found to have only a very limited effect on band broadening; an effect was only noticeable for the 50 μm capillary and relatively high flow rates.
CGE‐laser induced fluorescence of double‐stranded DNA fragments using GelGreen dye
Authors: Valdés Alberto , García‐Cañas Virginia , Cifuentes Alejandro
Published: February 2013

Nowadays, new solutions focused on the replacement of reagents hazardous to human health are highly demanded in laboratories and Green Chemistry. In the present work, GelGreen, a new nonhazardous DNA staining reagent, has been assayed for the first time to analyze double‐stranded DNA by CGE with LIF detection. The effect of GelGreen concentration on S/N ratio and migration time of a wide concentration range of standard DNA mixtures was evaluated. Under optimum GelGreen concentration in the sieving buffer efficient and sensitive separations of DNA fragments with sizes from 100–500 base pairs (bp) were obtained. A comparison in terms of resolution, time of analysis, LOD, LOQ, reproducibility, sizing performance, and cost of analysis was established between two optimized CGE‐LIF protocols for DNA analysis, one based on the dye YOPRO‐1 (typically used for CGE‐LIF of DNA fragments) and another one using the new GelGreen. Analyses using YOPRO‐1 were faster than those using GelGreen (ca. 31 min versus 34 min for the analysis of 100–500 bp DNA fragments). On the other side, sensitivity using GelGreen was twofold higher than that using YOPRO‐1. The cost of analysis was significantly cheaper (ninefold) using GelGreen than with YOPRO‐1. The resolution values and sizing performance were not significantly different between the two dyes (e.g. both dyes allowed the separation of fragments differing in only 2 bp in the 100–200 bp range). The usefulness of the separation method using GelGreen is demonstrated by the characterization of different amplicons obtained by PCR.
Dual‐templates molecularly imprinted monolithic columns for the evaluation of serotonin and histamine in CEC
Authors: Zaidi Shabi Abbas
Published: February 2013

To extend the application of molecularly imprinted polymers, the dual‐templates molecularly imprinted monolithic columns were developed in a capillary format. Two templates serotonin and histamine were simultaneously imprinted using two different functional monomers such as methacrylic acid (MAA) and methylenesuccinic acid (MSA) in a mixture of ethylene glycol dimethacrylate (EDMA) as a cross‐linker and AIBN as polymerization initiator dissolved in DMF as porogen. The resulting molecular imprinted polymers (MIPs) were characterized based on their performance in the CEC separation of two imprinted templates. The optimization parameters such as pH, ACN composition, and concentration of the eluent were varied to achieve best resolution and efficiency for CEC separation of templates with each MIP column. It was found that the MIP monolith column fabricated using MSA offered better resolution and separation efficiency compared to column fabricated with MAA. This work utilized the dual‐templates imprinting approach successfully and broadens the scope of multi‐templates imprinting capabilities in capillary format in CEC application.
Determination of α‐hydroxy acids and their enantiomers in fruit juices by ligand exchange CE with a dual central metal ion system
Authors: Kodama Shuji , Aizawa Sen‐ichi , Taga Atsushi , Yamamoto Atsushi , Honda Yoshitaka , Suzuki Kentaro , Kemmei Tomoko , Hayakawa Kazuichi
Published: February 2013

The content of α‐hydroxy acids and their enantiomers can be used to distinguish authentic and adulterated fruit juices. Here, we investigated the use of ligand exchange CE with two kinds of central metal ion in a BGE for the simultaneous determination of enantiomers of dl‐malic, dl‐tartaric and dl‐isocitric acids, and citric acid. Ligand exchange CE with 100 mM d‐quinic acid as a chiral selector ligand and 10 mM Cu(II) ion as a central metal ion could enantioseparate dl‐tartaric acid but not dl‐malic acid or dl‐isocitric acid. Addition of 1.8 mM Sc(III) ion to the BGE with 10 mM Cu(II) ion to create a dual central metal ion system permitted the simultaneous determination of these α‐hydroxy acid enantiomers and citric acid. The proposed ligand exchange CE was thus well suited for detecting adulteration of fruit juices.
Determination of volatile phenols in Chinese liquors by high‐performance liquid chromatography associated with β‐cyclodextrin and a protective barrier layer
Authors: Peng Qianrong , Dong Rui , Xun Siying , Yang Min , Feng Yongyv , Sun Di , Geng Pinglan
Published: February 2013

Volatile phenols have been considered as a class of highly flavour‐active compounds in non‐alcoholic and alcoholic beverages. However, the information on volatile phenols in Chinese liquors remains limited. This article presents a high‐performance liquid chromatography with a fluorescence detector (HPLC‐FLD) method for the determination of 10 volatile phenols in Chinese liquors. The method was based on the fluorescent nature of volatile phenols, the separation of the isomers p‐cresol and m‐cresol with β‐cyclodextrin as the resolving agent, and the use of a protective barrier layer for the capture of volatile phenols during the concentration process of the extract solution. The effects of several experimental parameters on recoveries of target volatile phenols were investigated. The correlation coefficients (R2) for calibration curves of the 10 phenols studies were in the range 0.9991–0.9998 when the linearity range was from 0.05 to 4 µg/ml. The proposed RP‐HPLC method was successfully applied to the analysis of Chinese liquors and the recoveries of the phenols were in the range 91.5–100.4% with RSD 0.9–2.2%, and the limits of detection were 0.0072–0.0234 µg/ml. Volatile phenols of different types and in differing amounts were found in several Chinese liquors. The method could be of use for routine evaluation of the quantity of volatile phenols during the production and ageing process of Chinese liquors. Copyright © 2013 John Wiley & Sons, Ltd.
Damage and Failure of Silver Based Ceramic/Metal Joints for SOFC Stacks
Authors: Bause T. , Malzbender J. , Pausch M. , Beck T. , Singheiser L.
Published: February 2013

The increasing interest in lightweight solid oxide fuel cell (SOFC) systems for mobile applications has raised the awareness for questions concerning mechanical robustness of sealing materials in thermo‐cyclic operation. In the planar SOFC design considered in the current work, a metallic silver based braze sealant is used. Although, these rather ductile metallic seals are considered to have advantages compared to brittle glass ceramics under thermal cycling conditions, the behavior of such sealant materials after application relevant thermal cyclic operation has not been reported so far. Hence, the post‐operational characterization of a series of silver braze sealed stacks operated isothermally and under thermal cycling conditions is reported with particular emphasis on the braze morphology. The stacks were disassembled after operation, specimens were extracted in various characteristic positions, and metallographically prepared cross‐sections were analyzed by optical and electron microscopy. It was observed that micro‐pores were formed in the sealant that terminated stack operation, and that the extent of this porosity depended on the actual operation conditions leading eventually to leakage and in some cases even to melting effects. The discussion of the results focuses on the influence of different operation conditions on the damage progress and failure of silver based braze joints.