bluuebunny/crossref_metadata_2025 huggingface dataset:
Polyvinylidene chloride supported L‐prolineamide as recoverable catalyst for asymmetric aldol reaction between ketone and aromatic aldehyde
Authors: Zhang Xuan , Zhao Wenshan , Yang Lili , Cui Yuanchen
Published: May 2012

A series of prolineamide modified by polyvinylidene chloride (PVDC) was synthesized and used as green recoverable organocatalysts for the asymmetric Aldol reactions between various ketones and aromatic aldehydes. The effects of solvent and catalyst dosage on the catalytic performances of as‐synthesized organocatalysts were investigated. It was found that as‐synthesized PVDC‐supported L‐prolineamides possessed good catalytic performance for the asymmetric Aldol reactions between cyclohexanone and a variety of aromatic aldehydes, affording high yields of up to 99%, excellent diastereoselectivities of up to above 8 : 92 d.r. value, and high enantioselectivities of up to above 92.3% e.e. value. In general, the catalytic performance of as‐synthesized organocatalysts closely depended on the catalyst dosage and solvent type as well. Particularly, as‐synthesized organocatalyst 1c, at a dosage of 5 mol % in 10 μL of water, exhibited high catalytic activity and stereoselectivity for the asymmetric Aldol reaction between cyclohexanone and p‐nitrobenzaldehyde at room temperature. In the meantime, it could be easily recovered and recycled, while the activity and enantioselectivity were nearly completely retained even after five cycles of recovery, showing promising application as an efficient green organocatalyst for the aforementioned asymmetric Aldol reactions. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Synthesis and thermal properties of bismaleimides with mesogen aromatic amide–ester and flexible polymethylenic group
Authors: Fache Bernard , Gallot Bernard , Gelin Marie Pierre , Milano Jean Claude , Pham Quang Trung
Published: May 2012

Four bismaleimides with mesogen “amide–ester” aromatic and flexible polymethylenic group variable length (8 ≤ n ≤ 11) were synthesized in two stages, producing yields exceeding 80%. These bismaleimides (BMIs) were obtained after several purifications by dissolution—precipitation in dimethylformamide–methanol (1/4) with over 94% purity (high‐performance liquid chromatography). These pure BMIs were characterized by nuclear magnetic resonance, Fourier transform infrared spectroscopy, and elemental analysis and studied by differential scanning calorimetry, thermogravimetric analysis, polarized light microscopy, and X‐ray diffraction. Solubilities and thermal properties show effects of parity. The even BMIs are more difficult to solubilize than the odd BMI. The melting points of the even BMI (approximately, 220°C) are far higher than those of odd BMI (approximately, 160°C). Crosslinking temperatures of even BMI are close to 230°C, whereas odd BMI crosslinking temperatures are higher (approximately, 250°C). Even BMIs give rise to a liquid crystal state upon melting. Under the same conditions, odd BMIs give rise to an amorphous state; however, after crosslinking, the four bismaleimides give rise to an ordered liquid crystal state of smectic type. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Photoactive behavior of polyacrylonitrile fibers based on silver and zirconium co‐doped titania nanocomposites: Synthesis, characterization, and comparative study of solid‐phase photocatalytic self‐cleaning
Authors: Moafi Hadi Fallah , Shojaie Abdollah Fallah , Zanjanchi Mohammad Ali
Published: May 2012

Silver and zirconium co‐doped and mono‐doped titania nanocomposites were synthesized and deposited onto polyacrylonitrile fibers via sol–gel dip‐coating method. The resulted coated‐fibers were characterized by X‐ray diffraction (XRD), scanning electron microscopy, energy dispersive spectroscopy, transmission electron microscopy, diffuse reflectance spectroscopy, thermogravimetric analysis, and BET surface area measurement. Photocatalytic activity of the TiO2‐coated and TiO2‐doped coated fibers were determined by photomineralization of methylene blue and Eosin Y under UV–vis light. The progress of photodegradation of dyes was monitored by diffuse reflectance spectroscopy. The XRD results of samples indicate that the TiO2, Ag‐TiO2, Zr‐TiO2, and Ag‐Zr‐TiO2 consist of anatase phase. All samples demonstrated photo‐assisted self‐cleaning properties when exposed to UV–vis irradiation. Evaluated by decomposing dyes, photocatalytic activity of Ag–Zr co‐doped TiO2 coated fiber was obviously higher than that of pure TiO2 and mono‐doped TiO2. Our results showed that the synergistic action between the silver and zirconium species in the Ag‐Zr TiO2 nanocomposite is due to both the structural and electronic properties of the photoactive anatase phase. These results clearly indicate that modification of semiconductor photocatalyst by co‐doping process is an effective method for increasing the photocatalytic activity. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Synthesis of new photocurable oligoisoprenes and kinetic studies of their radical photopolymerization
Authors: Jellali Rachid , Campistron Irène , Laguerre Albert , Pasetto Pamela , Lecamp Laurence , Bunel Claude , Mouget Jean‐Luc , Pilard Jean‐François
Published: May 2012

New photosensitive oligoisoprenes were synthesized by controlled degradation of high molecular weight cis‐1,4‐polyisoprene and successive chemical modification of the chain‐ends. Oligomers with diacrylate extremities were synthesized, characterized, and used in photocrosslinking reactions in different conditions. The photoinitiated polymerization of the diacrylate oligoisoprenes was carried out using 2,2‐dimethyl‐2‐hydroxyacetophenone (Darocur 1173) as initiator and the reaction was monitored by photocalorimetry‐DSC and real time FTIR spectroscopy. The influence of oxygen, photoinitiator concentration, light intensity, diluting agent, and oligomers molecular weight on the reaction rate was investigated. It was found that the presence of oxygen does not influence the photopolymerization kinetics of the diacrylate oligoisoprenes. Maximum conversion was obtained for a photoinitiator concentration of 5% (w/w) and for a light intensity of 13.5 mW/cm2. Decreasing the formulation viscosity by addition of a diluent (1,6‐hexanediol diacrylate) raised the photopolymerization rate, by increasing the reactive species mobility. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Versatility of a succinimidyl‐ester functional alkoxyamine for controlling acrylonitrile copolymerizations
Authors: Maric Milan , Consolante Valerie
Published: May 2012

Styrene/acrylonitrile (S/AN) and tert‐butyl methacrylate/acrylonitrile (tBMA/AN) copolymers were synthesized in a controlled manner (low polydispersity
$ {{\overline M _w } / {\overline M _n }} $
with linear growth of number average molecular weight
$ \overline M _n $
vs. conversion X) by nitroxide mediated polymerization (NMP) with a succinimidyl ester (NHS) terminated form of BlocBuilder unimolecular initiator (NHS‐BlocBuilder) in dioxane solution. No additional free nitroxide (SG1) was required to control the tBMA‐rich copolymerizations with NHS‐BlocBuilder, a feature previously required for methacrylate polymerizations with BlocBuilder initiators. Copolymers from S/AN mixtures (AN molar initial fractions fAN,0 = 0.13–0.86, T = 115°C) had
$ {{\overline M _w } / {\overline M _n }} $
= 1.14–1.26 and linear
$ \overline M _n $
versus conversion X up to X ≈ 0.6. tBMA/AN copolymers (fAN,0 = 0.10–0.81, T = 90°C) possessed slightly broader molecular weight distributions (
$ {{\overline M _w } / {\overline M _n }} $
= 1.23–1.50), particularly as the initial composition became richer in tBMA, but still exhibited linear plots of
$ \overline M _n $
versus conversion X up to X ≈ 0.6. A S/AN/tBMA terpolymerization (fAN,0 = 0.50, fS,0 = 0.40) was also conducted at 90°C and revealed excellent control with
$ \overline M _n $
= 13.6 kg/mol,
$ {{\overline M _w } / {\overline M _n }} $
= 1.19, and linear
$ \overline M _n $
versus conversion X up to X = 0.54. Incorporation of AN and tBMA in the final copolymer (molar composition FAN = 0.47, FtBMA = 0.11) was similar to the initial composition and represents initial designs to make tailored, acid functional AN copolymers by NMP for barrier materials. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Patient decision‐making modes and causes: A preliminary investigation
Authors: Kantor Paul B. , Bullinger Jonathan M. , Gal Cecilia S.
Published: May 2012

A recent study of patient decision making regarding acceptance of an implantable cardiac defibrillator (ICD) provides a substantial but nonrandom sample (N = 191) of telephone interviews with persons who have made an affirmative decision regarding an ICD. Using a coding scheme developed through qualitative analysis of transcribed interviews, these data can be subjected to exploratory statistical analysis. The reasons given by respondents for getting the ICD differed by both region and gender, and show some correlations with whether the device has or has not delivered any stimulation (shocks) since implantation. Cluster analysis reveals association among certain important themes in the discussion of the decision process, particularly linking rather opposite concepts into clusters related to specific dimensions. The results suggest the importance, to patients, of maintaining the integrity of the self by asserting control and independence. The majority of the respondents (61%) have not received the primary intended benefit of the device (stimulation). Thus, the findings suggest that psychological benefits alone of having the device (such as anxiety reduction) serve to justify acceptance of a computerized device. Implications for other lines of computerized health support and for further study of these issues are discussed.
Stabilizing Control of an Underactuated 2‐dimensional TORA with Only Rotor Angle Measurement
Authors: Gao Bingtuan , Xu Jing , Zhao Jianguo , Huang Xueliang
Published: May 2012

One dimensional translational oscillation with a rotational actuator (TORA) system has been used as a benchmark for motivating the study of nonlinear control techniques. In this paper, a novel underactuated 2‐dimensional TORA (2DTORA), which has one actuated rotor and two unactuated translational carts, is presented. The analysis of controllability around the system's equilibriums yielded the controllable equilibriums and the constraint on physical parameters. To stabilize the system to its controllable equilibriums from any initial conditions, we propose a simple linear controller containing the rotor angle and angular velocity. The controller was derived from a proper Lyapunov function, including the system's total energy, that was used to show the passivity property of the system. In addition, a high pass filter was adopted to approximately differentiate the rotor angle so that an estimated angular velocity was used in the controller rather than measuring the actual rotor angular velocity. As a result, only the angle measurement is required for the designed feedback controller to stabilize the underactuated system. Finally, simulation results verify our control design and analysis.
Methods of adjusted comparison of medians
Authors: Troendle James F. , Zhang Zhiwei , Mathews Megan E. , Guo Junchi
Published: May 2012

Consider the problem of making an adjusted comparison of the medians of two populations on an interval type outcome variable. A common method of doing this is through the use of a linear model requiring the residuals to be normally distributed. We describe here two methods based on a linear model after Box–Cox transformation of the outcome variable. The methods require a reference population, which could be either of the populations under study or their aggregate. We compare the new procedures with the comparison of normal means procedure and other procedures proposed for this problem by simulation. It is found that the procedure based on comparison of the predicted values obtained from the observed covariates of the reference population has higher power for testing and smaller mean square error of estimation than the other methods, while maintaining reasonable control of the type I error rate. We illustrate the methods by analyzing the duration of the second stage of labor for women in two large observation studies (Collaborative Perinatal Project and Consortium on Safe Labor) separated by 50 years. We recommend the method based on comparison of the predicted values of the transformed outcomes, with careful attention to how close the resulting residual distribution is to normal.
The causes of the nasolabial crease: A histomorphological study
Authors: Beer Gertrude M. , Manestar Mirjana , Mihic‐Probst Daniela
Published: May 2012

There are two main conflicting theories on how the nasolabial crease is formed: a muscular theory and a fascial theory. The muscular theory states that the nasolabial crease is mainly formed by the musculodermal insertions of the lip elevator muscles. The fascial theory claims that the nasolabial crease is mainly formed by dense fibrous tissue and by the firm fascial attachments to the fascia of the lip elevator muscles. If the muscular theory was true, the musculodermal insertions of the facial muscles could be interrupted directly by intradermal injections of low doses of botulinum toxin. Eight cadavers who presented with bilateral nasolabial creases were enrolled in the study. The nasolabial creases were harvested from 14 facial halves in their entire lengths and breadths with 5‐mm medial and lateral rims. The horizontally cut samples were stained with hematoxylin‐eosin (H&E) and Elastica van Gieson (EVG). Immunohistochemistry for the smooth muscle marker actin and the skeletal muscle marker desmin was also performed. In each of the nasolabial creases, numerous skeletal muscle fibers were found in the dermis, which confirmed the muscular theory of the cause of the nasolabial crease. In addition, muscle fibers were present in the dermis 4 mm medial and 4 mm lateral to the nasolabial crease, but the amounts were significantly less than the amount located directly in the crease. Botulinum toxin injected intradermally into the nasolabial crease might constitute a new treatment option to minimize or even eradicate the crease and the fold. Clin. Anat. 2013. © 2012 Wiley Periodicals, Inc.
Evaluation of variation in dynamic processes via online spectrometers
Authors: Kohonen Jarno , Alatalo Hannu , Reinikainen Satu‐Pia
Published: May 2012

Theory of sampling offers powerful tools for process optimization. An adequate sampling interval can be determined for spectral measurements when utilizing a multivariate extension of variography by applying score vectors as independent sources of uncertainty. The traditional way is to apply variographic analyses into single process variables independently. In the multivariate extension, those process variables are replaced with score vectors of principal component analysis. The combined uncertainty found this way depends not only on the variance in the spectra, but also, for example, on the number of utilized score vectors and the preprocessing method. This approach is illustrated with a crystallization process continuously followed with an attenuated total reflectance Fourier transform infrared instrument. The results show that the approach is highly applicable but should only be utilized as an indicative tool. Copyright © 2012 John Wiley & Sons, Ltd.
Syntheses and Highly Enantioselective Fluorescent Recognition of α‐Aminocarboxylic Acid Anions Using Chiral Oxacalix[2]arene[2]bisbinaphthes
Authors: Xu Kuoxi , Jiao Shuyan , Yao Wenyong , Xie En , Tang Baowei , Wang Chaojie
Published: May 2012

The triazine‐based bisbinaphthyl crown ethers oxacalix[2]arene[2]bisbinaphthes R-1, R-2, R-3 and S-1, S-2, S-3 were synthesized. The interactions of these compounds with various α‐aminocarboxylic acid anions were studied. The crown ethers were found to carry out highly enantioselective fluorescent recognition of α‐aminocarboxylic acid anions. It is observed that within a certain concentration range, one enantiomer of the chiral α‐aminocarboxylic acid anions can increase the fluorescence intensity of the crown ethers by fivefold to sixfold, whereas the other enantiomer scarcely enhances the fluorescence. Such unusually high enantioselective responses make these crown ethers very attractive as fluorescent sensors in determining the enantiomeric composition of α‐aminocarboxylic acid anions. Chirality 24:646–651, 2012. © 2012 Wiley Periodicals, Inc.
A direct suppression of green band emission of ZnO particles by adjusting the volume fraction of ethanol in reaction solutions
Authors: Yuan Run , Guo Jin , Zhang Shangzhou , Ma Zixia , Zhang Jun , Dai Zhenhong , Sun Yuanping
Published: May 2012

ZnO particles were successfully prepared by one step CTAB‐assisted hydrothermal method with different volume fraction of ethanol‐water mixture solution. The formed thorn‐ball like ZnO particles have an average size of 1 ∼ 2 μm in diameter. XRD result shows a hexagonal wurtzite structure and higher crystallinity. Room‐temperature photoluminescence shows a strong and dominated peak at ∼383 nm with a green emission at ∼510 nm. The intensity ratio between the UV and green emission increased from 1.31 to 7.53 when the volume fraction of ethanol was changed from 0% to 50%, which shows a direct suppression of structural defects just by adjusting the ethanol fraction in reaction solutions. The possible growth and luminescence mechanisms for thorn‐ball like ZnO particles are discussed.
Crystal habit prediction ‐ Including the liquid as well as the solid side
Authors: Schmidt C. , Ulrich J.
Published: May 2012

Commercially available methods of morphology prediction utilize molecular dynamics to estimate the crystal growth rates but predominantly consider the solid side. For the extension of these methods to a multi‐component solid‐liquid system the diffusion coefficient is required. Since, the diffusion coefficient enables the calculation of crystal growth rates and the morphology in presence of additives and solvents. Modeling the diffusion coefficient is achieved by conducting MD on a system consisting of the crystal surface and the liquid phase. The achieved results match very well with the calculated diffusion coefficient (Wilke‐Chang). In this case study benzoic acid is used as model substance with water as solvent.
Initial growth of Bi4 LaTi3 FeO15 thin films on SrTiO3, MgO and YSZ substrates
Authors: Wu Fei‐Xiang , Ji Wei‐Jing , Zhou Jian , Chen Y. B. , Yao Shu‐Hua , Zhang Shan‐Tao , Chen Yan‐Feng
Published: May 2012

The initial growth modes of Bi4LaTi3FeO15 thin films on (001) SrTiO3, (001) MgO and (001) Y:ZrO2 (YSZ) substrates are studied. Detailed crystal structure, microstructure and surface morphology characterizations substantiate that Bi4LaTi3FeO15 films grow on these substrates via three‐dimensional grain growth mode. The synthesized Bi4LaTi3FeO15 films on (001) MgO and (001) SrTiO3 substrates do have c‐axis epitaxial Aurivillius layered structure, and have relative smooth surface roughness. While films grown on (001) YSZ show the polycrystalline quality with large surface roughness. The different crystal quality of films grown on MgO/SrTiO3 and YSZ substrates is explained qualitatively by considering the different atomic surface structures of these substrates.
Aerial reconnaissance by Web photogrammetry in emergency management
Authors: Honma Ryohei , Doihara Takeshi , Nonaka Hideki
Published: May 2012

Measurement techniques by aerial images are effective for the acquisition of spatial information. Aerial images are used for quick disaster recovery and prevention of secondary disasters in the time of a nature disaster. Although automatic change detection is suitable for overviewing wide areas broadly, an actual damage survey eventually needs human interpretation of images. Web photogrammetry has been developed as a stereo view and measurement environment on a Web browser. This system can be used anywhere with no special knowledge or training in photogrammetry. This paper describes rapid mapping of disaster information by web photogrammetry. © 2012 Wiley Periodicals, Inc. Electron Comm Jpn, 95(6): 52–57, 2012; Published online in Wiley Online Library (wileyonlinelibrary.com). DOI 10.1002/ecj.10427
Dynamical recollection of interconnected neural networks using meta‐heuristics
Authors: Kuremoto Takashi , Watanabe Shun , Kobayashi Kunikazu , Feng Liang‐Bing , Obayashi Masanao
Published: May 2012

Interconnected recurrent neural networks are well‐known, with their abilities of associative memory of characteristic patterns. For example, the traditional Hopfield network (HN) can recall stored patterns stably, and Aihara's chaotic neural network (CNN) is able to realize dynamical recollection of a sequence of patterns. In this paper, we propose to use meta‐heuristic (MH) methods such as particle swarm optimization (PSO) and the genetic algorithm (GA) to improve traditional associative memory systems. Using PSO or GA, for CNN, the optimal parameters are found to accelerate the recollection process and raise the rate of successful recollection, and for HN, the optimized bias current is calculated to improve the network with dynamical association of a series of patterns. Simulations of binary pattern association showed the effectiveness of the proposed methods. © 2012 Wiley Periodicals, Inc. Electron Comm Jpn, 95(6): 12–23, 2012; Published online in Wiley Online Library (wileyonlinelibrary.com). DOI 10.1002/ecj.11372
IL‐10 deficiency blocks the ability of LPS to regulate expression of tolerance‐related molecules on dendritic cells
Authors: Zhou Fang , Ciric Bogoljub , Li Hongmei , Yan Yaping , Li Ke , Cullimore Melissa , Lauretti Elisabetta , Gonnella Patricia , Zhang Guang‐Xian , Rostami Abdolmohamad
Published: May 2012

Interleukin‐10 (IL‐10) is an anti‐inflammatory cytokine that plays an important role in regulating the local inflammatory immune response, but regulatory mechanisms of this cytokine have not been fully elucidated. Here, we demonstrate that IL‐10 deficiency renders LPS treatment ineffective in regulating the expression of CD40, CD80, CD86, B7‐H2, and B7‐DC on dendritic cells (DCs) and blocks upregulation of IL‐27. This inability to respond to LPS was found in both IL‐10−/− bone marrow derived and splenic DCs. Compared with wild‐type DCs, IL‐10−/– DCs expressed similar levels of TLR4 and CD14, but produced less LPS‐binding protein. The deficiency in LPS‐binding protein production may explain the failure of IL‐10−/− DCs to respond normally to LPS. Moreover, lack of IL‐10 modulated the proportions of CD11c+CD8+ and CD11c+B220+ DCs, which play an important role in local inflammatory responses and tolerance. IL‐10 deficiency also blocked expression of galectin‐1, CD205, and CD103, which are necessary for central and peripheral tolerance. While they did not respond to LPS, IL‐10−/− DCs produced increased levels of IL‐6 and CCL4 after TNF‐α treatment. Together, our results demonstrate that IL‐10 deficiency affects the immune functions of DCs, which may contribute to the increased severity of autoimmune diseases seen in IL‐10−/− mice.
A novel feedback mechanism by Ephrin‐B1/B2 in T‐cell activation involves a concentration‐dependent switch from costimulation to inhibition
Authors: Kawano Hiroki , Katayama Yoshio , Minagawa Kentaro , Shimoyama Manabu , Henkemeyer Mark , Matsui Toshimitsu
Published: May 2012

Bidirectional signals via Eph receptors/ephrins have been recognized as major forms of contact‐dependent cell communications such as cell attraction and repulsion. T cells express EphBs, and their ligands, the ephrin‐Bs, have been known as costimulatory molecules for T‐cell proliferation. Recently, another remarkable feature of ephrin‐As has emerged in the form of a concentration‐dependent transition from promotion to inhibition in axon growth. Here we examined whether this modification plays a role in ephrin‐B costimulation in murine primary T cells. Low doses of ephrin‐B1 and ephrin‐B2 costimulated T‐cell proliferation induced by anti‐CD3, but high concentrations strongly inhibited it. In contrast, ephrin‐B3 showed a steadily increasing stimulatory effect. This modulation was virtually preserved in T cells from mice simultaneously lacking four genes, EphB1, EphB2, EphB3, and EphB6. High concentrations of ephrin‐B1/B2, but not ephrin‐B3, inhibited the anti‐CD3‐induced phosphorylation of Lck and its downstream signals such as Erk and Akt. Additionally, high doses of any ephrin‐Bs could phosphorylate EphB4. However, only ephrin‐B1/B2 but not ephrin‐B3 recruited SHP1, a phosphatase to suppress the phosphorylation of Lck. These data suggest that EphB4 signaling could engage in negative feedback to TCR signals. T‐cell activation may be finely adjusted by the combination and concentration of ephrin‐Bs expressed in the immunological microenvironment.
A Comparative Study of Tricarbonylmanganese Photoactivatable CO Releasing Molecules (PhotoCORMs) by Using the Myoglobin Assay and Time‐Resolved IR Spectroscopy
Authors: Huber Wilhelm , Linder Rolf , Niesel Johanna , Schatzschneider Ulrich , Spingler Bernhard , Kunz Peter C.
Published: May 2012

Tricarbonylmanganese(I) complexes of the ligands tris(imidazol‐4‐yl)phosphane (4‐tipH), tris(1,4‐diisopropylimidazol‐2‐yl)phosphane (2‐tipiPr2), tris(pyridin‐2‐yl)phosphane (tpp) and tris(N‐methylimidazol‐2‐yl)carbinol (2‐ticNMe) were prepared. These act as N,N,N tripodal chelators. The solid‐state structure of [Mn(CO)3(tpp)]OTf was determined by X‐ray diffraction. The potential of these complexes to act as photoactivatable CO‐releasing molecules (PhotoCORMs) was studied with the UV/Vis spectroscopy‐based myoglobin assay as well as by time‐resolved IR spectroscopy. Within the series of compounds prepared, the steric bulk of the imidazolyl groups seems to significantly influence the CO‐release kinetics and stoichiometry when using the myoglobin assay. In contrast, the time‐resolved IR data suggest release of all carbonyl ligands upon irradiation. This effect points to a much closer association of myoglobin and PhotoCORMs than previously thought and will require further investigation.
Luminescence of ortho‐Metalated Iridium Complexes Encapsulated in Zeolite Supercages by the Ship‐in‐a‐Bottle Method
Authors: Xu Chen , Mochizuki Dai , Hashimoto Yuta , Honda Takehisa , Tsukahara Yasunori , Yamauchi Tomohisa , Wada Yuji
Published: May 2012

ortho‐Metalated iridium(III) complexes were synthesized in the supercages of faujasite‐type zeolites by a microwave‐assisted ship‐in‐a‐bottle procedure. IrIII was inserted by means of ion exchange followed by the addition of 2‐(2,4‐difluorophenyl)pyridine (dfppyH) or 2‐phenylpyridine (ppyH), demonstrating the first example of iridium–carbon sigma bond formation in zeolite cages. These zeolite powder samples containing IrIII complexes showed relatively high luminescence quantum yields [14.34 % for Ir(dfppy)3 and 4.76 % for Ir(ppy)3]. 2‐Phenylquinoline (phqH) afforded the corresponding ortho‐metalated complex that formed on the outer surface of the zeolite particles, because its large size prevented it from entering the supercages. The color of the emission from the zeolite powder samples could be tuned in a range from blue to green by the successive reaction of IrIII ions in the zeolite with the two ligands dfppyH and ppyH, leading to the formation of two individual types of complexes, Ir(dfppy)3 and Ir(ppy)3, in the supercages of the zeolite, which was confirmed by the characteristic emission spectrum of each complex.
Synthesis and Spectroscopic Characterisation of a Heterodinuclear Iron(III)‐Copper(II) Complex Based on an Asymmetric Dinucleating Ligand System
Authors: Heims Florian , Mereacre Valeriu , Ciancetta Antonella , Mebs Stefan , Powell Annie K. , Greco Claudio , Ray Kallol
Published: May 2012

The site‐directed generation of a heterodinuclear FeIIICuII complex by using a new asymmetric dinucleating ligand FloH is reported. The iron(III) ion is introduced first on the preferential metal‐binding site of the ligand that leads to the formation of the thermodynamically favored five‐membered chelate rings upon metal‐binding. Copper(II) is introduced in the next step. The stepwise metalation strategy reported here may be extended to the preparation of other heterometallic complexes with the view of avoiding a statistical distribution. Such complexes can offer novel spectroscopic properties, electronic structures, and reactivities in comparison to their homometallic analogues.
Enantioselective Asymmetric Michael Addition of Cyclic Diketones to β,γ‐Unsaturated α‐Keto Esters
Authors: Wang Yi‐Feng , Wang Ke , Zhang Wei , Zhang Bin‐Bin , Zhang Chi‐Xiao , Xu Dan‐Qian
Published: May 2012

An efficient, organocatalytic enantioselective addition of cyclic diketones with β,γ‐unsaturated α‐keto esters has been developed that affords products in high yields (up to 95 %) and excellent enantioselectivity (up to >99 % ee) under mild conditions with a low catalyst loading (2.5 mol‐%). The unsaturated α‐keto esters are effectively coordinated and activated through hydrogen bonds with the squaramides and proved to be excellent hydrogen‐bond acceptors in this asymmetric organocatalytic reaction. This reaction provides valuable and easy access to chiral Michael adducts, which are important moieties in the skeletons of biological and pharmaceutical molecules.
Base‐Promoted Heterocyclization of Fluorinated Alkynylphosphonates with Select ortho‐Aminobenzonitriles
Authors: Duda Blazej , Tverdomed Sergey N. , Ionin Boris I. , Röschenthaler Gerd‐Volker
Published: May 2012

The heterocyclization reactions of CF2‐containing alkynylphosphonates with 2‐aminobenzonitriles to give 2,3‐difunctionalized 4‐aminoquinolines were investigated. The influence of the R1 and R2 substituents and CF2X groups on the synthetic efficiency and specificity is also disclosed.
Surfactant‐induced electroosmotic flow in microfluidic capillaries
Authors: Azadi Glareh , Tripathi Anubhav
Published: May 2012

Control of EOF in microfluidic devices is essential in applications such as protein/DNA sizing and high‐throughput drug screening. With the growing popularity of poly(methyl methacrylate) (PMMA) as the substrate for polymeric‐based microfludics, it is important to understand the effect of surfactants on EOF in these devices. In this article, we present an extensive investigation exploring changes in EOF rate induced by SDS, polyoxyethylene lauryl ether (Brij35) and CTAB in PMMA microfluidic capillaries. In a standard protein buffer (Tris‐Glycine), PMMA capillaries exhibited a cathodic EOF with measured mobility of 1.54 ± 0.1 (× 10−4 cm2/V.s). In the presence of surfactant below a critical concentration, EOF was independent of surfactant concentration. At high concentrations of surfactants, the electroosmotic mobility was found to linearly increase/decrease as the logarithm of concentration before reaching a constant value. With SDS, the EOF increased by 257% (compared to buffer), while it was decreased by 238% with CTAB. In the case of Brij35, the electroosmotic mobility was reduced by 70%. In a binary surfactant system of SDS/CTAB and SDS/Brij35, addition of oppositely charged CTAB reduced the SDS‐induced EOF more effectively compared to nonionic Brij35. We propose possible mechanisms that explain the observed changes in EOF and zeta potential values. Use of neutral polymer coatings in combination with SDS resulted in 50% reduction in the electroosmotic mobility with 0.1% hydroxypropyl methyl cellulose (HPMC), while including 2% poly (N,N‐dimethylacrylamide) (PDMA) had no effect. These results will potentially contribute to the development of PMMA‐based microfluidic devices.
On‐line preconcentration of perfluorooctanoic acid and perfluorooctanesulfonic acid by nonaqueous capillary electrophoresis
Authors: Knob Radim , Maier Vítězslav , Petr Jan , Ranc Václav , Ševčík Juraj
Published: May 2012

Separation of major environmental pollutants as perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid (PFOS) by capillary electrophoresis is reported for the first time. It is not possible to resolve the solutes in an aqueous media. However, the use of methanol and acetonitrile as the background electrolyte (BGE) solvents allowed their rapid separation in an uncoated capillary. A major effort was put into BGE optimization in respect to both separation efficiency and detection for further on‐line preconcentration. 5 mmol.L‑1 naphthalene‐1‐sulfonic acid and 10 mmol.L‑1 triethylamine dissolved in ACN/MeOH (50:50 v/v) provided best separation and detection conditions. Next, the large‐volume sample stacking and the field‐amplified sample injection were applied and compared. Large‐volume sample stacking improved limits of detection (LODs) with regard to the standard injection by 69 times for PFOA and 143 times for PFOS with LODs of 280 and 230 nmol.L‑1, respectively. Field‐amplified sample injection improved LODs 624 times for PFOAand 806 times for PFOS with LODs 31 and 40 nmol.L‑1, respectively. Both preconcentration methods showed repeatabilities of migration times less than 1.2% RSD intraday and 6.6% RSD interday. The method was applied on PFOA and PFOS analysis in a sample of river water treated with solid‐phase extraction, which further improved LOD toward 5.6 × 10‑10 mol.L‑1 for PFOS and 6.4 × 10‑10 mol.L‑1 for PFOA and allows the method to be used for river water contamination screening or decomposition studies.
On the formation of carbonate adducts of fatty alcohols, sterols, and sugars in biological conditions
Authors: do Lago Claudimir L. , Vidal Denis T. R. , Rossi Marcelo R. , Hotta Guilherme M. , da Costa Eric T.
Published: May 2012

The formation and properties of carbonate adducts of some organic hydroxy compounds in aqueous medium were investigated. Fatty alcohols and sugars were chosen as representative classes of biological interest, and the medium was carbonated aqueous solution with pH ranging from 3.0 to 8.3. Capillary electrophoresis with two capacitively coupled contactless conductivity detectors (C4Ds) was used for quantitation and to obtain the mobility of the monoalkyl carbonates (MACs), which were used to determine the equilibrium and kinetic constants of the reaction as well as the diffusion coefficients. For increasing chain length of the alcohols, the equilibrium constant tends to the unit, which suggests that fatty alcohols can form the corresponding MACs. The formation of MACs for cyclohexanol and cyclopentanol also suggest the existence of similar species for sterols. Carbonate adducts of fructose, glucose, and sucrose were also detected, which suggests that these counterparts of the well‐known phosphates can also occur in the cytosol. Our calculations suggest that one in 1000 to one in 10 000 molecules of these hydroxy compounds would be available as the corresponding MAC in such a medium. Experiments carried out at pH values less than 3.0 showed that there is a catalytic effect of hydronium on the interconversion of bicarbonate and a MAC. Taking into account the great number of hydroxy compounds similar to the ones investigated and that bicarbonate is ubiquitous in living cells, one can anticipate the existence of a whole new class of carbonate adducts of these metabolites.
Vortex‐assisted surfactant‐enhanced‐emulsification liquid–liquid microextraction for the determination of triazine herbicides in water samples by microemulsion electrokinetic chromatography
Authors: Li Ran‐Hong , Liu Dong‐Hui , Yang Zhong‐Hua , Zhou Zhi‐Qiang , Wang Peng
Published: May 2012

A novel method based on the combination of microemulsion electrokinetic chromatography (MEEKC) and vortex‐assisted surfactant‐enhanced‐emulsification liquid–liquid microextraction (VSLLME) was developed for the determination of five triazine herbicides (simazine, atrazine, ametryn, prometryn, and terbutryn) in water samples. The five triazine herbicides were baseline separated by using the microemulsion buffer containing a 10 mmol/L borate buffer at pH 9.5, 2.5% (w/v) SDS as surfactant, 0.8% (w/v) ethyl acetate as oil phase, and 6.0% (w/v) 1‐butanol as cosurfactant. The optimum extraction conditions of VSLLME were as follows: 100 μL chloroform was used as extraction solvent, 5.0 × 10−5 mol/L Tween‐20 was chosen as the surfactant to enhance the emulsification, and the extraction process was carried out by vortex mixing for 3 min. Under these optimum experimental conditions, the calibration curve was linear in the range of 2.0–200.0 ng/mL, with the correlation coefficients (r2) varying from 0.9927 to 0.9958. The detection limits of the method varied from 0.41 to 0.62 ng/mL. The purposed method was applied to the determination of five triazine herbicides in real water samples, and the recoveries were between 80.6 and 107.3%.
Hollow‐fiber liquid‐phase microextraction for the determination of pesticides and metabolites in soils and water samples using HPLC and fluorescence detection
Authors: Asensio‐Ramos María , Hernández‐Borges Javier , González‐Hernández Guillermo , Rodríguez‐Delgado Miguel Ángel
Published: May 2012

A new and simple method has been developed for the determination of a group of four benzimidazole pesticides (carbendazim/benomyl, thiabendazole, and fuberidazole), a carbamate (carbaryl), and an organophosphate (triazophos), together with two of their main metabolites (2‐aminobenzimidazole, metabolite of carbendazim/benomyl, and 1‐naphthol, metabolite of carbaryl) in soils. First, an ultrasound‐assisted extraction (UAE) was performed, followed by evaporation and reconstitution in water. Then, extraction and preconcentration of the analytes was accomplished by two‐phase hollow‐fiber liquid‐phase microextraction (HF‐LPME) using 1‐octanol as extraction solvent. Parameters that affect the extraction efficiency in HF‐LPME technique (organic solvent, pH of the sample, extraction time, stirring speed, temperature, and ionic strength) were deeply investigated. Optimum HF‐LPME conditions involved the use of a 2.0 cm polypropylene fiber filled with 1‐octanol to extract 10 mL of an aqueous soil extract at pH 9.0 containing 20% (v/v) of NaCl for 30 min at 1440 rpm. Separation and quantification was achieved by HPLC with fluorescence detection (FD). The proposed optimum UAE‐HF‐LPME‐HPLC‐FD methodology provided good calibration, precision, and accuracy results for two soils of different physicochemical properties. LODs were in the range 0.001–6.94 ng/g (S/N = 3). With the aim of extending the validation, the HF‐LPME method was also applied to different types of waters (Milli‐Q, mineral and run‐off), obtaining LODs in the range 0.0002–0.57 μg/L.
Potential effects of probiotics in cheese and yogurt production: A review
Authors: Plessas Stavros , Bosnea Loulouda , Alexopoulos Athanasios , Bezirtzoglou Eugenia
Published: May 2012

The implementation of probiotic cultures in the dairy industry has been a modern trend in the last few years. The main reasons are the enhancement of human nutrition and health and better organoleptic properties of food products. Probiotic microorganisms can provide protection against pathogenic microorganisms in the gut, by reducing the severity of some types of diarrhea, and against the risk of atopic eczema in high‐risk infants. They also assist in the development of the immune system, by improving colonic health and nutrition. This has led to a better acceptance by the consumers, since it has been demonstrated recently that the microorganisms of the respective food products are also present in the natural microflora of the gut. This review discusses the criteria to select probiotic microorganisms as well as their positive impact on cheese and yogurt production.
Controllable‐Nitrogen Doped Carbon Layer Surrounding Carbon Nanotubes as Novel Carbon Support for Oxygen Reduction Reaction
Authors: Kuo P.‐L. , Hsu C.‐H. , Wu H.‐M. , Hsu W.‐S. , Kuo D.
Published: May 2012

Novel nitrogen‐doped carbon layer surrounding carbon nanotubes composite (NC‐CNT) (N/C ratio 3.3–14.3 wt.%) as catalyst support has been prepared using aniline as a dispersant to carbon nanotubes (CNTs) and as a source for both carbon and nitrogen coated on the surface of the CNTs, where the amount of doped nitrogen is controllable. The NC‐CNT so obtained were characterized with scanning electron microscopy (SEM), Raman spectroscopy, X‐ray photoelectron spectroscopy (XPS), and nitrogen adsorption and desorption isotherms. A uniform dispersion of Pt nanoparticles (ca. 1.5–2.0 nm) was then anchored on the surface of NC‐CNT by using aromatic amine as a stabilizer. For these Pt/NC‐CNTs, cyclic voltammogram measurements show a high electrochemical activity surface area (up to 103.7 m2 g–1) compared to the commercial E‐TEK catalyst (55.3 m2 g–1). In single cell test, Pt/NC‐CNT catalyst has greatly enhanced catalytic activity toward the oxygen reduction reaction, resulting in an enhancement of ca. 37% in mass activity compared with that of E‐TEK.
A H2SO4 Loaded Polybenzimidazole (PBI) Membrane for High Temperature PEMFC
Authors: Wu X. , Scott K.
Published: May 2012

Sulfuric acid loaded polybenzimidazole (PBI) membranes were prepared with loading levels up to 10.58 (acid molecule per repeat unit of PBI) and characterized with Fourier transform infrared spectroscopy. Ionic conductivity of the PBI–H2SO4 membrane was found greater than that of the PBI–H3PO4 membrane. Through plane conductivity of a PBI–H2SO4 membrane with loading level 9.65 was >0.2 S cm–1 at 150 °C. However, the conductivity of PBI–H2SO4 membrane increased greatly with increasing relative humidity. Membrane electrode assemblies using PBI–H2SO4 membrane exhibited better power density performances with pre‐humidified H2 and air than that with none‐humidified gases. Polymer electrolyte membrane fuel cells with PBI–H2SO4 membrane in a single cell fixture demonstrated a peak power density >0.35 W cm–2 with H2 and air.
Microstructural Change of Ni–GDC Cermet Anode in the Electrolyte‐supported Disk‐type SOFC upon Daily Start‐up and Shout‐down Operations
Authors: Eguchi K. , Kamiuchi N. , Kim J.‐Y. , Muroyama H. , Matsui T. , Kishimoto M. , Saito M. , Iwai H. , Yoshida H. , Shikazono N. , Kasagi N. , Akikusa J. , Eto H. , Ueno D. , Kawano M. , Inagaki T.
Published: May 2012

The daily start‐up and shut‐down operations were carried out for the 1 kW‐class solid oxide fuel cell stack composed of 46 electrolyte‐supported disk‐type planar cells made by Mitsubishi Materials Corporation and Kansai Electric Power Company. The representative Ni–gadolinia doped ceria cermet anodes in the deteriorated cells were analyzed by the dual‐beam focused ion beam‐scanning electron microscope. The anode microstructures were reconstructed and the microstructural parameters such as triple phase boundary (TPB) length were quantified. The surface area of nickel phase decreased with an increase in the deterioration rate, leading to a reduction in the TPB length. Furthermore, the TPB length had a strong correlation with the voltage deterioration rate.
Optimized Selection of Unrelated Subjects for Whole‐Genome Sequencing Studies of Rare High‐Penetrance Alleles
Authors: Edwards Todd L. , Li Chun
Published: May 2012

Sequencing studies using whole‐genome or exome scans are still more expensive than genome‐wide association studies on a per‐subject basis. As a result, only a subset of subjects from a larger study will be selected for sequencing. To perform an agnostic investigation of the entire genome, subjects may be selected that capture independent ancestral lineages, i.e., founder genomes, and thus avoid redundant information from regions that were inherited identical by descent (IBD) from a common ancestor. We present SampleSeq2 that can be used to select a subset of optimally unrelated subjects with minimal IBD sharing. It also can be used to estimate the number, GT, of founder chromosomes in a sample or select the minimum number of subjects that will carry a target GT. We evaluated SampleSeq2 compared to a random draw of a small number of subjects both by simulation and using the Anabaptist genealogy. SampleSeq2 provided an increase in GT relative to a random draw across a range of small sample sizes. This increase in founder chromosomes improves the power of association tests, mitigates the effect of cryptic relatedness on parameter estimates, increases the total yield of alleles from sequencing, and minimizes the average size of regions shared IBD around disease alleles in cases. Genet. Epidemiol. 36:472‐479, 2012. © 2012 Wiley Periodicals, Inc.
Right diaphragmatic defect in hepatic hydrothorax exposed by contrast-enhanced ultrasonography after radiofrequency ablation
Authors: Matono Tomomitsu , Koda Masahiko , Murawaki Yoshikazu
Published: May 2012

A 68-year-old male with liver cirrhosis and hepatocellular carcinoma treated by radiofrequency ablation was hospitalized for right hepatic hydrothorax and ascites. Perflubutane injected into the peritoneal cavity after an ultrasonography contrast agent revealed jet-like flow from the ascites to a pleural effusion, indicating a diaphragmatic defect. A hepatic hydrothorax was sutured under thoracoscopy and did not recur. An intraperitoneal injection of perflubutane enables a less-invasive diagnosis of a diaphragmatic defect. (HEPATOLOGY 2012;)
Theoretical investigations on structure, density, detonation properties, and sensitivity of the derivatives of PYX
Authors: Liu Hui , Wang Fang , Wang Gui‐Xiang , Gong Xue‐Dong
Published: May 2012

The NH2, NO2, N3, NHNO2, and ONO2 substitution derivatives of PYX (2,6‐bis(picrylamino)‐3,5‐dinitropyridine) were studied at the B3LYP/6‐31G** level of density functional theory. The sublimation enthalpies and heats of formation (HOFs) in gas phase and solid state of these compounds were calculated. The theoretical predicted density (ρ), detonation pressure (P), and detonation velocity (D) showed that these derivatives have better detonation performance than PYX. The effects of substituent groups on HOF, ρ, P, and D were discussed. The order of contribution of various groups to P and D was ONO2 > NO2 > NHNO2 > N3 > NH2. Sensitivity was evaluated using the frontier orbital energies, bond orders, bond dissociation enthalpies (BDEs), and characteristic heights (h50). The trigger bonds in the pyrolysis process for these PYX derivatives may be Ring‐NO2, NHNO2, or ONO2 varying with the substituents. The h50 of most compounds are larger than that of CL‐20, and those of NH2, NO2, and most ONO2 derivatives are larger than that of RDX. The BDEs of the trigger bonds of all but the ONO2 derivatives are sufficiently large. Taking both detonation performance and sensitivity into consideration, some derivatives of PYX may be good candidates of explosives. © 2012 Wiley Periodicals, Inc.
Computational design of improved two‐photon active caging compounds based on nitrodibenzofuran
Authors: Dreuw Andreas , Polkehn Matthias A. , Binder Robert , Heckel Alexander , Knippenberg Stefan
Published: May 2012

Nitrodibenzofuran (NDBF) has recently been established as photolabile protecting group and efficiently used as two‐photon active cage. In this work, a computational approach is exploited to rationally design improved two‐photon active caging groups based on this NDBF chromophore. For this objective, first the two‐photon absorption (TPA) properties of NDBF are investigated in detail and a suitable theoretical approach for the reliable simulation of TPA spectra of this class of compounds is identified. Then, virtual chemical modifications are performed by introduction of substituents at the chromophore and replacement of the central furan ring by pyrolle, thiophene, and borrole heterocycles. Subsequently, the TPA properties of the resulting compounds are computed, and the influences of the chemical modifications on TPA properties investigated in detail. The most promising candidates with largely increased two‐photon uncaging efficiencies are dimethylamino‐substituted derivatives of NDBF, nitrodibenzopyrrol, and nitrodibenzothiophene. © 2012 Wiley Periodicals, Inc.