bluuebunny/crossref_metadata_2025 huggingface dataset:
Synthesis of 4‐Iodo‐3‐furanones Utilizing Electrophile‐Induced Tandem Cyclization/1,2‐Migration Reactions.
Authors: Crone Benedikt , Kirsch Stefan F.
Published: November 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Direct Lactone Formation by Using Hypervalent Iodine(III) Reagents with KBr via Selective C—H Abstraction Protocol.
Authors: Dohi Toshifumi , Takenaga Naoko , Goto Akihiro , Maruyama Akinobu , Kita Yasuyuki
Published: November 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Cation‐Exchange Resin as Efficient, Cost‐Effective and Recyclable Catalyst for the Synthesis of 3‐Propargylindoles.
Authors: Yadav J. S. , Reddy B. V. Subba , Kumar G. G. K. S. Narayana , Rao K. V. Raghavendra
Published: November 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Synthesis of Sulfur‐Substituted Quinolizidines and Pyrido[1,2‐a]azepines by Ring‐Closing Metathesis.
Authors: Chou Shang‐Shing P. , Liang Chu‐Fang , Lee Tse‐Ming , Liu Chih‐Fen
Published: November 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Polysubstituted 2,3‐Dihydrofuro[2,3‐b]pyridines and 3,4‐Dihydro‐2H‐pyrano[2,3‐b]pyridines via Microwave‐Activated Inverse Electron Demand Diels—Alder Reactions.
Authors: Hajbi Youssef , Suzenet Franck , Khouili Mostafa , Lazar Said , Guillaumet Gerald
Published: November 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Synthesis of Diastereomeric 2,4‐Disubstituted Pyrano[2,3‐b]quinolines from 3‐Formyl‐2‐quinolones Through O—C Bond Formation via Intramolecular Electrophilic Cyclization.
Authors: Singh Mrityunjay K. , Chandra Atish , Singh Bhawana , Singh Radhey M.
Published: November 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Synthesis of Homochiral 2‐(2‐Arylethyl)piperazines.
Authors: Schaus John M. , Krushinski Joseph H. , Ruley Kevin M. , Rocco Vincent P.
Published: November 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Michael Addition of Amine Derivatives to Conjugate Phosphinyl and Phosphonyl Nitrosoalkenes. Preparation of α‐Amino Phosphine Oxide and Phosphonate Derivatives.
Authors: de los Santos Jesus M. , Ignacio Roberto , Aparicio Domitila , Palacios Francisco
Published: November 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
An Enantiospecific Synthesis of (+)‐Demethoxyerythratidinone from (S)‐Malic Acid: Key Observations Concerning the Diastereocontrol in Malic Acid Derived N‐Acyliminium Ion Cyclizations.
Authors: Zhang Fengzhi , Simpkins Nigel S. , Wilson Claire
Published: November 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Synthesis, Structure and Stereochemistry of Quinoline Alkaloids from Choisya ternata.
Authors: Boyd Derek R. , Sharma Narain D. , Loke Pui L. , Malone John F. , McRoberts W. Colin , Hamilton John T. G.
Published: November 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Bifunctional Acyclic Nucleoside Phosphonates. Part 2. Symmetrical 2‐{[Bis(phosphono)methoxy]methyl}ethyl Derivatives of Purines and Pyrimidines.
Authors: Vrbkova Silvie , Dracinsky Martin , Holy Antonin
Published: November 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Synthesis of the Germination Stimulant 3‐Methyl‐2H‐furo[2,3‐c]pyran‐2‐one and Analogous Compounds from Carbohydrates.
Authors: Goddard‐Borger Ethan D. , Ghisalberti Emilio L. , Stick Robert V.
Published: November 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Novel Synthesis of Naturally Occurring Pulvinones: A Heck Coupling, Transesterification, and Dieckmann Condensation Strategy.
Authors: Bernier David , Brueckner Reinhard
Published: November 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
New Kehokorins and Trichiols from the Myxomycete Trichia favoginea.
Authors: Watanabe Kousuke , Ohtsuki Takashi , Yamamoto Yukinori , Ishibashi Masami
Published: November 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Development of a Spectral Clustering Method for the Analysis of Molecular Data Sets.
Authors: Brewer Mark L.
Published: November 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
A Large Descriptor Set and a Probabilistic Kernel‐Based Classifier Significantly Improve Druglikeness Classification.
Authors: Li Qingliang , Bender Andreas , Pei Jianfeng , Lai Luhua
Published: November 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Design of Inhibitors of the MurF Enzyme of Streptococcus pneumoniae Using Docking, 3D‐QSAR, and de Novo Design.
Authors: Khedkar Santosh A. , Malde Alpeshkumar K. , Coutinho Evans C.
Published: November 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Advances on the Nanostructuration of Magnetic Molecules on Surfaces: The Case of Single‐Molecule Magnets (SMM)
Authors: Gomez‐Segura Jordi , Veciana Jaume , Ruiz‐Molina Daniel
Published: November 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Nonaqueous Sold—Gel Routes to Metal Oxide Nanoparticles
Authors: Niederberger Markus
Published: November 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
1‐Aminoalkanephosphonic Acids — Six Decades of Exploration
Authors: Kudzin Zbigniew H.
Published: November 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Calixarene‐Derived Fluorescent Probes
Authors: Kim Jong Seung , Quang Duong Tuan
Published: November 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Utilization of Plant Viruses in Bionanotechnology.
Authors: Steinmetz Nicole F. , Evans David J.
Published: November 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Usability levels for sparse linear algebra components
Authors: Sosonkina M. , Liu F. , Bramley R.
Published: November 2007

Sparse matrix computations are ubiquitous in high‐performance computing applications and often are their most computationally intensive part. In particular, efficient solution of large‐scale linear systems may drastically improve the overall application performance. Thus, the choice and implementation of the linear system solver are of paramount importance. It is difficult, however, to navigate through a multitude of available solver packages and to tune their performance to the problem at hand, mainly because of the plethora of interfaces, each requiring application adaptations to match the specifics of solver packages. For example, different ways of setting parameters and a variety of sparse matrix formats hinder smooth interactions of sparse matrix computations with user applications. In this paper, interfaces designed for components that encapsulate sparse matrix computations are discussed in the light of their matching with application usability requirements. Consequently, we distinguish three levels of interfaces, high, medium, and low, corresponding to the degree of user involvement in the linear system solution process and in sparse matrix manipulations. We demonstrate when each interface design choice is applicable and how it may be used to further users' scientific goals. Component computational overheads caused by various design choices are also examined, ranging from low level, for matrix manipulation components, to high level, in which a single component contains the entire linear system solver. Published in 2007 by John Wiley & Sons, Ltd.
Meteor: a middleware infrastructure for content‐based decoupled interactions in pervasive grid environments
Authors: Jiang Nanyan , Quiroz Andres , Schmidt Cristina , Parashar Manish
Published: November 2007

Emerging pervasive information and computational environments require a content‐based middleware infrastructure that is scalable, self‐managing, and asynchronous. In this paper, we propose associative rendezvous (AR) as a paradigm for content‐based decoupled interactions for pervasive grid applications. We also present Meteor, a content‐based middleware infrastructure to support AR interactions. The design, implementation, and experimental evaluation of Meteor are presented. Evaluations include experiments using deployments on a local area network, the wireless ORBIT testbed at Rutgers University, and the PlanetLab wide‐area testbed, as well as simulations. Evaluation results demonstrate the scalability, effectiveness, and performance of Meteor to support pervasive grid applications. Copyright © 2007 John Wiley & Sons, Ltd.
Using MOS current dividers for linearization of programmable gain amplifiers
Authors: Sanz M. Teresa , Celma Santiago , Calvo Belén
Published: November 2007

Two highly linear, digitally programmable gain amplifiers are presented and compared in terms of linearity, frequency, area and power consumption. High linearity and wide gain tuning range with moderate area consumption are the main benefits of both configurations. Furthermore, constant bandwidth is achieved by means of switched compensation capacitor arrays. Three‐bit prototypes were integrated in a 0.35 µm–3.3 V CMOS process with 2.5 V supply voltage. Experimental distortion levels are better than −68 dB for 1 MHz and 1 Vp−poutput signals in both configurations; hence, the suitability of the linearization technique based on MOS current dividers is shown. Copyright © 2007 John Wiley & Sons, Ltd.
Prospective associations between depressive symptoms and eating disorder symptoms among adolescent girls
Authors: Marmorstein Naomi R. , von Ranson Kristin M. , Iacono William G. , Malone Stephen M.
Published: November 2007

Objective:

Although eating disorders are frequently associated with depression, evidence regarding which problem predicts the other is conflicting, and little research has addressed the developmental course of this relation. This study examined longitudinal associations between depression and eating pathology across adolescence.

Method:

Participants were 754 girls participating in the community‐based Minnesota Twin Family Study. Depressive symptoms and eating pathology were assessed at approximately ages 11, 14, and 17.

Results:

As expected, substantial continuity in both eating pathology and depressive symptoms occurred across time. Analysis of cross‐lag paths controlling for earlier levels of symptoms indicated that overall levels of eating pathology predicted later depressive symptoms from 11 to 14 and from 14 to 17.

Conclusion:

Adolescent girls with high levels of eating‐related pathology appear to be at risk for later depression. © 2007 by Wiley Periodicals, Inc. Int J Eat Disord 2008
Understanding how parents cope with living with someone with anorexia nervosa: Modelling the factors that are associated with carer distress
Authors: Kyriacou Olivia , Treasure Janet , Schmidt Ulrike
Published: November 2007

Objective:

Caring for a person with anorexia nervosa (AN) has been associated with psychological distress and poor life quality of carers. Addressing carers' needs may impact on prognostic outcome. The aim was to explore and model factors associated with distress in parents of people with AN (N = 151).

Method:

A cross‐sectional design was used to assess caregiving strains (Pearlin Stress Scales) and psychological distress (Hospital Anxiety and Depression Scale).

Results:

Over 70% of carers (N = 107) scored at or above the suggestive threshold (score ≥ 8) for anxiety, and 38% (N = 54) for depression. Over 50% of carers (N = 78) scored at or above the clinical threshold (score ≥ 11) for anxiety, and 13% (N = 20) for depression. A model of carer distress after multiple regression analyses showed three significant associated variables. In order of significance, self‐related strains, carer sex, and interpersonal strains accounted for 41% of the variance, (F(3, 112) = 29.85, p < .001).

Conclusion:

Interventions aimed at improving outcome in AN may need to focus on reducing caregiving strains and carers' distress, particularly of mothers. © 2007 by Wiley Periodicals, Inc. Int J Eat Disord 2008
Yttrium, Lanthanide and Mixed Y‐Ln Vanadates Prepared from Molecular Precursors Based on EDTA
Authors: Deligne Nicolas , Gonze Vanessa , Bayot Daisy , Devillers Michel
Published: November 2007

Yttrium(III) and lanthanide(III) vanadates corresponding to the general formula AVO4 (A = Y, Pr, Sm, Eu, Gd, Dy, Er) were prepared by a nonconventional soft chemistry route in which coordination compounds of the different elements to be incorporated were used as molecular precursors. In this case, EDTA‐based yttrium(III), lanthanide(III) and vanadium(V) complexes were synthesised, characterised and used as precursors for the preparation of zircon‐type AVO4 materials at a moderate temperature of 800 °C, as evidenced by XRD and Raman analyses. Solid solutions such as Y1–xPrxVO4 and Y1–xGdxVO4 were also obtained. Linear correlations between chemical compositions and lattice parameters or Raman shifts were observed. SEM was used to characterise the particle size and morphology. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
Biogenesis and Biomimetic Chemistry: Can Complex Natural Products Be Assembled Spontaneously?
Authors: Gravel Edmond , Poupon Erwan
Published: November 2007

With selected examples, we try to demonstrate that complex structures of natural products can be generated with surprising spontaneity. In such cases it appears that molecular complexity might emerge with minimal (if any) enzymatic assistance, through self‐construction mechanisms. Rearrangements of linear molecules, light‐induced reactions, dimerizations and multi‐component reactions could explain the formation of secondary metabolites through the intrinsic reactivity of their precursors. A few examples, amongst the most significant, are presented, along with efficient biomimetic syntheses that strengthen the hypotheses.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
One‐Pot Synthesis of Functionalized 3‐(Trifluoromethyl)phenols by [3+3] Cyclization of 1,3‐Bis(silyl enol ethers) with α,β‐Unsaturated Trifluoromethyl Ketones
Authors: Mamat Constantin , Pundt Thomas , Tam Dang T. H. , Klassen Renske , Reinke Helmut , Köckerling Martin , Langer Peter
Published: November 2007

Functionalized 3‐(trifluoromethyl)phenols were prepared by formal [3+3] cyclization of 1,3‐bis(silyl enol ethers) with readily available open‐chained and cyclic α,β‐unsaturated trifluoromethyl ketones. The reaction of 3,4‐dihydro‐5‐(trifluoroacetyl)‐2H‐pyran with 1,3‐bis(silyl enol ethers) resulted in a domino process to give new functionalized dihydropyrans. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
Synthesis of Enantiopure (S)‐Indolylglycine by Organocatalyzed Friedel–Crafts Alkylation of Indole
Authors: Wanner Martin J. , Hauwert Peter , Schoemaker Hans E. , de Gelder René , van Maarseveen Jan H. , Hiemstra Henk
Published: November 2007

Tritylsulfenyl‐ and 2‐nitrophenylsulfenyl‐substituted glyoxyl imines were used in chiral phosphoric acid catalyzedFriedel–Crafts (FC) reactions with indole. High yields and ee values ranging from 86 % for Nps‐protected (S)‐indolylglycine to 88 % for Trs‐protected (R)‐indolylglycine were obtained. On a preparative scale, a FC product with 99.5 % ee and 71 % yield was readily obtained by crystallization of the reaction mixture. Removal of the Nps protecting group under mild acidic conditions did not affect the stereochemical integrity of the α‐carbon atom and (S)‐indolylglycine was afforded in ≥98 % ee.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
Bacterial characterization using protein profiling in a microchip separations platform
Authors: Pizarro Shelly A. , Lane Pamela , Lane Todd W. , Cruz Evelyn , Haroldsen Brent , VanderNoot Victoria A.
Published: November 2007

A rapid microanalytical protein‐based approach to bacterial characterization is presented. Chip gel electrophoresis (CGE) coupled with LIF detection was used to analyze lysates from different bacterial cell lines to obtain signature profiles of the soluble protein composition. The study includes Escherichia coli, Bacillus subtilis, and Bacillus anthracis (Δ Sterne strain) vegetative cells as well as endospores formed from the latter two species as model organisms to demonstrate the method. A unified protein preparation protocol was developed for both cell types to streamline the benchtop process and aid future automation. Cells and spores were lysed and proteins solubilized using a combination of thermal and chemical lysis methods. Reducing agents, necessary to solubilize spore proteins, were eliminated using a small‐scale rapid size‐exclusion chromatography step to eliminate interference with down‐stream protein labeling. This approach was found to be compatible with nonspore cells (i.e., vegetative cells) as well, not adversely impacting the protein signatures. Data are presented demonstrating distinct CGE protein signatures for our model organisms, suggesting the potential for discrimination of organisms on the basis of empirical protein patterns. The goal of this work is to develop a fast and field‐portable method for characterizing bacteria via their proteomes.
Comparative study of floating and dynamic injection modes in electrokinetic separative microsystems
Authors: Blas Maximilien , Delaunay Nathalie , Rocca Jean‐Louis
Published: November 2007

Miniaturization of analytical instruments has attracted a wide interest in analytical chemistry over the past decade because of the advantages of reduced reagent consumption, better analytical performance, and shorter analysis time. The widespread interest in this field has resulted in efforts to develop chips. For chips involving separation, injection is a key step to achieve efficient and sensitive analysis. This work presents a comparative study of two electrokinetic injection modes in chips: the floating, which has been mainly used up to now, and the dynamic. This study was done with a crossjunction, either with numerical simulations or with experiments. Experiments were carried out with homemade PDMS–glass microsystems involving zonal electrophoresis analysis of five derivatized amino acids. Injected amount, reproducibility, separation efficiency, and analyte discrimination were evaluated and discussed. The experimental results were successfully correlated with numerical simulations. It appeared that the dynamic injection mode is much more appropriate than the floating mode as it is faster (reduction by a factor 2 of the total analysis time here), more reproducible (RSD of peak areas equal to 1.3% (n = 4) instead of 10% (n = 4)), and leads to more efficient separation (about 20% with 3 cm separation channel length) for the same injected amount, whatever the amount, because the sample plug is less dispersed.
Spatially addressable protein array: ssDNA‐directed assembly for antibody microarray
Authors: Ng Jin Kiat , Ajikumar Parayil Kumaran , Tang Yew Chung , Lee Jim Yang , Stephanopoulos Gregory , Too Heng‐Phon
Published: November 2007

Protein microarray offers a means for high‐throughput profiling of cellular proteins to provide insights into the mechanisms of biological processes. This study describes the design and fabrication of a robust platform, spatially addressable protein array (SAPA), by exploring the specificity of ssDNA hybridization for self‐assembly of semi‐synthetic ssDNA‐antibody conjugates which capture antigens from complex biological samples. This approach does not involve the direct immobilization of antibodies nor antigen, but instead captures the target antigens in the solution phase followed by self‐directed assembly of the complex onto the surface. In an effort to optimize the platform, the effects of surface chemistry, nonspecific protein adsorption, facile preparation, and purification of ssDNA‐conjugated antibody and capture of the antigen from a complex biological sample such as cell lysate were examined. This platform allowed antigen detection in cell lysate with high sensitivity (1 pM). The method described herein can be extended to the high‐throughput detection of other interacting molecules in solution phase and their subsequent assembly onto any substrate.
A simplified method for capillary embedment into microfluidic devices – exemplified by sol–gel‐based preconcentration
Authors: Thorslund Sara , Johannesson Nina , Nikolajeff Fredrik , Bergquist Jonas
Published: November 2007

We here describe an alternative method of embedding functionalized capillaries into microdevices fabricated in PDMS. The capillaries have square‐shaped outer dimensions and fit into elastic PDMS channel networks of similar dimensions. By modifying the capillary off‐chip, the technique makes it possible to integrate a new chip function without risking contamination of already existing chemically patterned areas because of new reagent solutions. Leak‐free insertion of these capillaries has earlier been reported, where a thin layer of uncured PDMS bonded the capillary to the microchannel and the lid structure. In this new approach, oxygen plasma is used to bond the square capillary to the PDMS, eliminating the risk of clogging the microsystem with uncured prepolymer. The new embedding technique was exemplified and evaluated by inserting a square capillary piece containing monolithic sol–gel for sample preconcentration application. The assembled microdevice was run with mass spectrometric detection, showing that peptides were preconcentrated without leakage from either the sol–gel itself or around the inserted capillary. Repeated preconcentration runs showed migration times better than 3% for all peptides. We believe that the presented microchip assembling technique greatly simplifies the insertion of functionalized capillary pieces, e.g., an initial preconcentrator to a PDMS device containing other downstream modules.
Temperature gradient focusing in a PDMS/glass hybrid microfluidic chip
Authors: Matsui Takuya , Franzke Joachim , Manz Andreas , Janasek Dirk
Published: November 2007

This paper reports the application of temperature gradient focusing (TGF) in a PDMS/glass hybrid microfluidic chip. With TGF, by the combination of a temperature gradient along a microchannel, an applied electric field, and a buffer with a temperature‐dependent ionic strength, analytes are focused by balancing their electrophoretic velocities against the bulk velocity of the buffer containing the analytes. In this work, Oregon Green 488 carboxylic acid was concentrated approximately 30 times as high as the initial concentration in 45 s at moderate electric strength of 70 V/cm and a temperature gradient of 55°C across the PDMS/glass hybrid microfluidic chip with a 1 cm long capillary.
Turn‐induced isotachophoretic focusing in microfluidic channels
Authors: Paschkewitz John S. , Molho Joshua I. , Xu Hui , Bharadwaj Rajiv , Park C. Charles
Published: November 2007

Multifunctional microfluidic platforms that use ITP for sample stacking require the use of serpentine channels. When ITP is carried out in serpentine passages, the sample band shows dramatically different behavior than that observed in conventional on‐chip CE. The band skew, defined as the distance between the leading and trailing edge of the band, is reduced and the sample is focused on the outside wall of the turn. This effect is explained using a simplified analytical model for the infinite Peclet number limit and the predicted trends are compared to full numerical simulations and experimental measurements. The outward focusing is driven by a wall‐normal electric field that results from the skewed leading buffer‐trailing buffer (LB‐TB) interface. The results indicate that the degree of outward focusing is controlled by the ratio of the LB and TB conductivities, the ratio of the channel width to turn radius, and the Peclet number. Increasing the band skew, which shows a complex dependence on the nondimensional parameters, maximizes the outward focusing effect.
Monitoring of enzymatic reactions using conventional and on‐chip capillary electrophoresis with contactless conductivity detection
Authors: Schuchert‐Shi Aiping , Kubáň Pavel , Hauser Peter C.
Published: November 2007

The use of CE with contactless conductivity detection was evaluated for monitoring enzymatic reactions. The nonionic species ethanol, glucose, ethyl acetate, and ethyl butyrate were made accessible for analysis by CE via charged products or by‐products obtained in enzymatic conversions using hexokinase, glucose oxidase, alcohol dehydrogenase, and esterase. Two of the reactions, namely the conversion of glucose with glucose oxidase and that of ethylacetate with esterase, were also successfully demonstrated on a microchip device. Quantification for ethyl acetate, taken as an example, was found possible with a detection limit of approximately 7 μM.
A microfluidic device for parallel 3‐D cell cultures in asymmetric environments
Authors: Frisk Thomas , Rydholm Susanna , Liebmann Thomas , Svahn Helene Andersson , Stemme Göran , Brismar Hjalmar
Published: November 2007

We demonstrate a concept for how a miniaturized 3‐D cell culture in biological extracellular matrix (ECM) or synthetic gels bridges the gap between organ‐tissue culture and traditional 2‐D cultures. A microfluidic device for 3‐D cell culture including microgradient environments has been designed, fabricated, and successfully evaluated. In the presented system stable diffusion gradients can be generated by application of two parallel fluid flows with different composition against opposite sides of a gel plug with embedded cells. Culture for up to two weeks was performed showing cells still viable and proliferating. The cell tracer dye calcein was used to verify gradient formation as the fluorescence intensity in exposed cells was proportional to the position in the chamber. Cellular response to an applied stimulus was demonstrated by use of an adenosine triphosphate gradient where the onset of a stimulated intracellular calcium release also depended on cell position.
Microfluidic cell disruption system employing a magnetically actuated diaphragm
Authors: Huh Yun Suk , Choi Jong Hyun , Park Tae Jung , Hong Yeon Ki , Hong Won Hi , Lee Sang Yup
Published: November 2007

A microfluidic cell lysis chip equipped with a micromixer and SPE unit was developed and used for quantitative analysis of intracellular proteins. This miniaturized sample preparation system can be employed for any purpose where cell disruption is needed to obtain intracellular constituents for the subsequent analysis. This system comprises a magnetically actuated micromixer to disrupt cells, a hydrophobic valve to manipulate the cell lysate, and a packed porous polymerized monolith chamber for SPE and filtering debris from the cell lysate. Using recombinant Escherichia coli expressing intracellular enhanced green fluorescent protein (EGFP) and lipase as model bacteria, we optimized the cell disruption condition with respect to the lysis buffer composition, mixing time, and the frequency of the diaphragm in the micromixer, which was magnetically actuated by an external magnetic stirrer in the micromixer chamber. The lysed sample prepared under the optimal condition was purified by the packed SPE in the microfluidic chip. At a frequency of 1.96 Hz, the final cell lysis efficiency and relative fluorescence intensity of EGFP after the cell disruption process were greater than 90 and 94%, respectively. Thus, this microfluidic cell disruption chip can be used for the efficient lysis of cells for further analysis of intracellular contents in many applications.
Electrophoresis on a microfluidic chip for analysis of fluorescence‐labeled human rhinovirus
Authors: Kolivoška Viliam , Weiss Victor U. , Kremser Leopold , Gaš Bohuslav , Blaas Dieter , Kenndler Ernst
Published: November 2007

We report the analysis of human rhinovirus serotype 2 (HRV2) on a commercially available lab‐on‐a‐chip instrument. Due to lack of sufficient native fluorescence, the proteinaceous capsid of HRV2 was labeled with Cy5 for detection by the red laser (λex 630 nm) implemented in the instrument. On the microdevice, electrophoresis of the labeled virus was possible in a BGE without stabilizing detergents, which is in contrast to conventional CE; moreover, analysis times were drastically shortened to the few 10 s range. Resolution of the sample constituents (virions, a contaminant present in all virus preparations, and excess dye) was improved upon adaptation of the separation conditions, mainly by adjusting the SDS concentration of the BGE. Purity of fractions from size‐exclusion chromatography after labeling of virus was assessed, and affinity complex formation of the labeled virus with various recombinant very‐low‐density lipoprotein receptor derivatives differing in the number of concatenated V3 ligand binding repeats was monitored. Virus analysis on microchip devices is of particular interest for experiments with infectious material because of easy containment and disposal of samples. Thus, the employment of microchip devices in routine analysis of viruses appears to be exceptionally attractive.
Endostatin inhibits endochondral ossification
Authors: Sipola A. , Ilvesaro J. , Birr E. , Jalovaara P. , Pettersson R. F. , Stenbäck F. , Ylä‐Herttuala S. , Hautala T. , Tuukkanen J.
Published: November 2007

Background

Angiogenesis is essential for the replacement of cartilage by bone during skeletal growth and regeneration. Vascular endothelial growth factor‐A (VEGF‐A) is a key regulator of angiogenesis whereas endostatin, a potent inhibitor of endothelial cell proliferation and migration, is a natural antagonist of VEGF‐A. The regulatory role of these peptides in angiogenesis and bone formation was investigated using adenoviral gene delivery of VEGF‐A and endostatin in a mouse ectopic ossification model.

Methods

Bone formation was induced in the hamstring muscles of adult mice with native bone morphogenetic protein (BMP) extract implemented in gelatine gel together with VEGF‐A and endostatin recombinant adenoviral vectors. The mice were sacrificed 1, 2, and 3 weeks after the operation and ectopic bone formation was followed radiographically and histologically.

Results

Significant bone formation was induced by BMP extract in all treatment groups. VEGF‐A stimulated and endostatin prevented the formation of FVIII‐related antigen‐positive vessels as well as the number of cartilage‐resorbing chondroclasts/osteoclasts. Endostatin alone or in conjugation with VEGF‐A reduced bone formation. Excess of VEGF‐A stimulated and endostatin reduced bone formation, respectively, at the 3‐week time point.

Conclusions

Our findings indicate that endostatin retards the cartilage phase in endochondral ossification which subsequently reduces bone formation in our experimental model. We conclude that bone growth and healing, which share features with ectopic bone formation, may be regulated by endostatin. Copyright © 2007 John Wiley & Sons, Ltd.
Incorporation of all‐trans retinoic acid into lipoplexes inhibits nuclear factor κB activation mediated liver injury induced by lipoplexes in mice
Authors: Charoensit Pensri , Kawakami Shigeru , Higuchi Yuriko , Hashida Mitsuru
Published: November 2007

Background

All‐trans retinoic acid (ATRA) is a natural derivative of vitamin A, which is well known to suppress inflammatory cytokine production. To date, there have been few reports about the systemic use of ATRA for inflammation because of acute resistance and the highly lipophilic nature of ATRA.

Methods

ATRA‐lipoplexes were prepared by mixing CMV‐Luc plasmid DNA with ATRA‐incorporated 1,2‐dioleoyl‐3‐trimethylammoniopropane (DOTAP)/cholesterol liposome. After intravenous injection, tissue accumulation, transfection efficacy, NFκB activation, cytokine production, and hepatic toxicity of ATRA‐lipoplexes were evaluated and compared with lipoplexes lacking ATRA.

Results

The particle size and zeta potential of ATRA‐lipoplexes were similar to those of lipoplexes. After intravenous injection of ATRA‐lipoplexes, tissue accumulation in liver and gene expression in liver and lung were similar to those of lipoplexes, supporting the hypothesis that ATRA incorporation did not affect the delivery and gene transfection efficacy. In addition, ATRA incorporated in ATRA‐lipoplexes was delivered to liver in a manner similar to that for ATRA incorporated in liposomes. In addition, intravenous injection of ATRA‐lipoplexes inhibited the activation of NFκB in liver, and subsequently suppressed the serum levels of tumor necrosis factor‐alpha (TNF‐α) and alanine aminotransferase (ALT) compared with lipoplexes. Liver histology data also demonstrated a low degree of liver injury produced by ATRA‐lipoplexes compared with lipoplexes.

Conclusions

ATRA‐incorporated lipoplexes effectively suppress NFκB activation, cytokine response and liver injury induced by lipoplexes without affecting gene delivery and transfection efficacy in vivo. Copyright © 2007 John Wiley & Sons, Ltd.
Congo and Korea: a study in divergence
Authors: Garner Phillip
Published: November 2007

The growth experiences of the Democratic Republic of the Congo and South Korea over the last several decades have been polar opposites. Despite this divergence in economic outcomes, the two countries shared some initial similarities including very low income, high population growth rates, harsh colonial regimes, military coups and Cold War politics. There were also important initial differences in population density, ethnolinguistic diversity, natural resource endowments and geography. Given its enormous mineral wealth, economic prospects initially appeared brighter in the Congo than in Korea to most contemporary observers. This paper explores the possible causes of divergences in the two countries by examining initial conditions, economic and demographic trends, geography and governance. Copyright © 2007 John Wiley & Sons, Ltd.
SFM studies of carbon ion induced damages in plasmid DNA
Authors: Brezeanu Mihail , Taucher‐Scholz Gisela , Psonka Katarzyna , Träger Frank , Hubenthal Frank
Published: November 2007

In this study we present for the first time detailed scanning force microscopy (SFM) investigations of carbon ion induced damages in plasmid DNA in order to obtain information about the biological effectiveness of particle radiation. For this purpose, we have combined SFM and gel electrophoresis measurements in a dose range between D = 0 Gy and 5000 Gy. After irradiation with C ions, the percentage of double‐strand breaks (DSBs) increases drastically, i.e. from initially 0% for D = 0 Gy to 38% for D = 5000 Gy. Increasing the dose over the total range is accompanied by a shortening of the average fragment length from 〈L〉 = 1100 nm to 〈L〉 = 575 nm. In addition to our experiments, the average numbers of induced DSBs per irradiated plasmid and per broken plasmid have been calculated from the SFM measurements. The most important among the numerous results is that a significant amount of plasmids has suffered more than two DSBs for all applied doses, indicating multiple DSBs. The number of DSBs per broken plasmid increases from approximately 1.7 after irradiation with a dose of D = 250 Gy to 3.2 after exposure to the highest dose of D = 5000 Gy. The results provide experimental data for the spatially correlated production of DSBs after carbon irradiation, that are relevant to the understanding of its biological effectiveness. Copyright © 2007 John Wiley & Sons, Ltd.
The weed community affects yield and quality of soybean (Glycine max (L.) Merr.)
Authors: Gibson David J , Millar Katherine , Delong Michael , Connolly John , Kirwan Laura , Wood Andrew J , Young Bryan G
Published: November 2007

BACKGROUND: The relationship between the weed community and soybean (Glycine max (L.) Merr.) seed yield and quality was assessed in two experiments in Illinois, USA. In one field different proportions of target weeds (Ambrosia trifida L., Amaranthus rudis J. Sauer, and Setaria faberi F. Herrm) were sown into experimental plots, and the other field was naturally infested with these and other weeds. The composition of the weed communities in both fields was compared to soybean yield, biomass, canopy cover and quality (% protein, oil, relative water content, and seed weight) using non‐metric dimensional scaling ordination.

RESULTS: In the experimentally sown plots, low yield and low quality soybeans were harvested from plots dominated by the target weeds, particularly A. trifida, and a suite of subordinate volunteers. In the naturally infested field, highest soybean protein was associated with S. faberi early in the season and Ambrosia artemisiifolia and Ipomea hederacea later in the season, and low amounts of A. rudis throughout the growing season.

CONCLUSION: Similar results from the two experiments indicate that soybean seed yield and quality are affected by the composition of the weed community. Producers need to manage the weed community to optimize seed quality. Copyright © 2007 Society of Chemical Industry
Physico‐enzymatic production of monoacylglycerols enriched with very‐long‐chain polyunsaturated fatty acids
Authors: Pawongrat Ratchapol , Xu Xuebing , H‐Kittikun Aran
Published: November 2007

BACKGROUND: Monoacylglycerols (MAG) containing polyunsaturated fatty acids (PUFA), especially eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), have interesting applications. The enzymatic processing of such MAG directly from fish oils is highly interesting, integrating the processing of MAG and concentration of EPA and DHA. The aim of this study was to develop an efficient enzymatic glycerolysis system together with physical fractionation for the production of PUFA‐MAG from tuna oil.

RESULTS: Novozym 435 was eventually selected after evaluation together with immobilized lipase AK in a tertiary alcohol‐based system. A further evaluation of solvent mixtures involving tertiary alcohols was made, taking ease of operation into consideration. It turned out that a number of mixtures gave a similar performance to that of tert‐butanol (TB). Basic reaction parameters were thoroughly evaluated. In the batch reaction system with TB as solvent, the recommended conditions were: glycerol/tuna oil 4:1 (mol/mol), TB/tuna oil 2:1 (wt/wt), 15 wt% Novozym 435, and temperature 40 °C. Under these conditions, the yield of MAG was up to 90% after 3 h incubation. Crude MAG from the production was fractionated to produce MAG with higher EPA and DHA content. Using acetone as solvent at 0 °C led to ca 50% yield of MAG but contained EPA and DHA up to 71% in comparison with ca 30% in tuna oil.

CONCLUSION: Potentially practical process steps have been developed for the production of MAG containing a high content of EPA and DHA from natural fish oils with high efficiency and simplicity. Copyright © 2007 Society of Chemical Industry
Growth performance of rats fed raw and extruded African breadfruit‐based complementary diets: A response surface analysis
Authors: Nwabueze Titus U
Published: November 2007

BACKGROUND: African breadfruit, from which diverse food forms are produced, is popular in most West African tropical regions. The present study is part of a larger research project aimed at developing appealing, processed, nutritious products from blends of breadfruit, corn and defatted soybean by utilising extrusion cooking using response surface analysis. The study describes the ability or otherwise of raw and extruded African breadfruit‐based diets, similar to weaning diets simulated with rats, to support growth of children and infants.

RESULTS: Maximum protein efficiency and net protein ratios of 2.22 and 3.69, respectively, were obtained with rats fed diets made from 40 g 100 g−1 African breadfruit + 5 g 100 g−1 corn + 55 g 100 g−1 soybean extrudates at 18 mL 100 mL−1 feed moisture and 140 rpm screw speed. It compared favourably with a casein standard and was 54–69% and 42–55% higher than those fed raw diets.

CONCLUSION: Extrusion cooking significantly improved the nutritional quality of African breadfruit–corn–defatted soybean as reflected in their protein efficiency and net protein values. The superiority in protein quality of diet 1 (containing 40 g 100 g−1 breadfruit, 5 g 100 g−1 corn and 55 g 100 g−1 defatted soybean) over the other experimental diets has serious nutritional implication in dietary diversification to address protein‐energy malnutrition prevalent in Nigeria and other West African countries especially where African breadfruit is known to be highly cultivated as a food resource. Copyright © 2007 Society of Chemical Industry
Determination of lawsone in henna powders by high performance thin layer chromatography
Authors: El‐Shaer Nagwa S. , Badr Jihan M. , Aboul‐Ela Maha A. , Gohar Yousry M.
Published: November 2007

The lawsone content has been evaluated quantitatively in eight commercial henna powders and two collected henna leaves. The phenolic, chloroform‐soluble fraction of the majority of the examined samples showed the presence of lawsone and two other pigments. Here we aimed to optimize high performance thin layer chromatography for the determination of lawsone. Upon using the optimized method the examined samples showed considerable variation in lawsone concentration ranging from 0.004 up to 0.608 wt%, indicating that some samples were almost devoid of lawsone. Some of these products were subjected to preliminary in vivo toxicity studies.
Statistical mixture design – principal component optimization for selective compound extraction from plant material
Authors: Soares Patricia Kaori , Bruns Roy Edward , Scarminio Ieda Spacino
Published: November 2007

A simplex centroid design is used to optimize solvent mixtures for selective extraction of compounds from Erythrina speciosa Andrews leaves. Three main groups of compounds characterized by chromatographic retention times of 1.7, 3.1, and 6.6 min were extracted. The chromatographic peak heights registered at 1407 equally spaced times for each design extract were converted into principal components (PCs). Three PCs account for 89.1% of the data variance and have important loading values at the above retention times. Quadratic mixture models were found to adequately describe the response surfaces of their PC score values. Maximizing the first PC scores while minimizing the second and third ones results in an optimum 83% dichloromethane–17% acetone mixture that selectively extracts the group of compounds with retention times around 3.1 min. Maximizing the second PC scores and minimizing the third PC scores leads to a 78% hexane–22% acetone mixture adequate for extracting the 6.6 min retention time compounds as well as other compounds with high retention times. The 1.7 min group of compounds is most efficiently extracted on maximizing the third PC that results in a 50% ethanol–50% acetone mixture. The Derringer–Suich algorithm confirmed the determination of these optimized mixtures.
Prediction of the location of stationary steady‐state zone positions in counterflow isotachophoresis performed under constant voltage in a vortex‐stabilized annular column
Authors: Harrison Schurie L. M. , Ivory Cornelius F.
Published: November 2007

A theoretical model is presented and an analytical expression derived to predict the locations of stationary steady‐state zone positions in ITP as a function of current for a straight channel under a constant applied voltage. Stationary zones may form in the presence of a countercurrent flow whose average velocity falls between that of a pure leader zone and of a pure trailer zone. A comparison of model predictions with experimental data from an anionic system shows that the model is able to predict the location of protein zones with reasonable accuracy once the ITP stack has formed. This result implies that an ITP stack can be precisely directed by the operator to specific positions in a channel whence portions of the stack can be removed or redirected for further processing or analysis.
Improved determination of 5‐fluorouracil and its prodrug tegafur in pharmaceuticals by large‐volume sample stacking in CE
Authors: Yang Yanmin , Liu Qian , Tao Wenyan , Nie Lihua , Yao Shouzhuo
Published: November 2007

On‐line determination of the anti‐tumor drug 5‐fluorouracil (5‐FU) and its prodrug, tegafur (TF) was achieved for the first time by capillary electrophoresis with large‐volume sample stacking (CE–LVSS). The optimal electrophoretic buffer consisted of 30 mM phosphate buffer at pH 8.0. Without the LVSS procedure, the limits of detection (LOD) were 600.5 ng/mL and 771.4 ng/mL for 5‐FU and TF, respectively. With the LVSS procedure, the sensitivity was significantly improved by about two orders of magnitude (the LODs of 5‐FU and TF were decreased to 7.9 ng/mL and 6.5 ng/mL, respectively). The %RSD was less than 5%. This method compared favorably with other reported techniques and was applied successfully to the quantitative analysis of anti‐tumor drugs in commercial injection preparations. The results show that the method is simple, fast (less than 3 min), highly selective, and sensitive.