bluuebunny/crossref_metadata_2025 huggingface dataset:
Intermediate follow‐up following intravascular stenting for treatment of coarctation of the aorta
Authors: Forbes Thomas J. , Moore Phillip , Pedra Carlos A.C. , Zahn Evan M. , Nykanen David , Amin Zahid , Garekar Swati , Teitel David , Qureshi Shakeel A. , Cheatham John P. , Ebeid Makram R. , Hijazi Ziyad M. , Sandhu Satinder , Hagler Donald J. , Sievert Horst , Fagan Thomas E. , Ringwald Jeremy , Du Wei , Tang Liwen , Wax David F. , Rhodes John , Johnston Troy A. , Jones Thomas K. , Turner Daniel R. , Pass Robert , Torres Alejandro , Hellenbrand William E.
Published: September 2007

Background: We report a multiinstitutional study on intermediate‐term outcome of intravascular stenting for treatment of coarctation of the aorta using integrated arch imaging (IAI) techniques. Methods and Results: Medical records of 578 patients from 17 institutions were reviewed. A total of 588 procedures were performed between May 1989 and Aug 2005. About 27% (160/588) procedures were followed up by further IAI of their aorta (MRI/CT/repeat cardiac catheterization) after initial stent procedures. Abnormal imaging studies included: the presence of dissection or aneurysm formation, stent fracture, or the presence of reobstruction within the stent (instent restenosis or significant intimal build‐up within the stent). Forty‐one abnormal imaging studies were reported in the intermediate follow‐up at median 12 months (0.5–92 months). Smaller postintervention of the aorta (CoA) diameter and an increased persistent systolic pressure gradient were associated with encountering abnormal follow‐up imaging studies. Aortic wall abnormalities included dissections (n = 5) and aneurysm (n = 13). The risk of encountering aortic wall abnormalities increased with larger percent increase in CoA diameter poststent implant, increasing balloon/coarc ratio, and performing prestent angioplasty. Stent restenosis was observed in 5/6 parts encountering stent fracture and neointimal buildup (n = 16). Small CoA diameter poststent implant and increased poststent residual pressure gradient increased the likelihood of encountering instent restenosis at intermediate follow‐up. Conclusions: Abnormalities were observed at intermediate follow‐up following IS placement for treatment of native and recurrent coarctation of the aorta. Not exceeding a balloon:coarctation ratio of 3.5 and avoidance of prestent angioplasty decreased the likelihood of encountering an abnormal follow‐up imaging study in patients undergoing intravascular stent placement for the treatment of coarctation of the aorta. We recommend IAI for all patients undergoing IS placement for treatment of CoA. © 2007 Wiley‐Liss, Inc.
Successful complex bifurcation stenting of a native SFA after failed femoropopliteal bypass grafting
Authors: Kelley Michael , Mishkel Gregory
Published: September 2007

Endovascular treatments are becoming more beneficial in the treatment of complex peripheral arterial disease. We report a novel case of using a y‐stenting technique at 2 bifurcation sites in the femoropopliteal region, to revascularize a long native SFA occlusion after failed femoropopliteal bypass grafting. © 2007 Wiley‐Liss, Inc.
Efficacy and long‐term patency of fenestrated amplatzer devices in children
Authors: Lammers Astrid E. , Derrick Graham , Haworth Sheila G , Bonhoeffer Philipp , Yates Robert
Published: September 2007

Introduction: Novel transcatheter techniques to control interatrial communications exist. Devices with restrictive fenestrations can be implanted to maintain patency of an atrial septostomy, or reduce an interatrial communication. Experience with these devices in children is limited. Patients and Methods: Fenestrated atrial septal devices were implanted into 10 children (5 male, age 1.5–15.5 years). Devices were modified by the manufacturer (MM, n = 6), or by a modification of an atrial septal occlusion device by the operator (OM, n = 4). Seven devices were implanted after atrial septal puncture and septostomy for severe symptomatic pulmonary hypertension (PHT) [4 heart failure, 3 syncope], according to World Health Organisation Guidelines. Two devices were implanted to reduce left to right shunting through large atrial septal defects with associated PHT. One device was implanted acutely to offload the left atrium during extracorporal circulatory support prior to heart transplantation. Warfarin (n = 5), aspirin (n = 4), or heparin (n = 1) were used for prevention of fenestration thrombosis. Results: Symptoms in all patients with PHT improved after implantation; syncope recurred with fenestration occlusion in one patient. Nine patients were followed up to a mean of 26 months. Five devices (all MM; warfarin n = 4, aspirin n = 1) remained patent on echocardiography. Fenestrations occluded in 4 children after median follow‐up of 10 months (MM n = 1, OM n = 3, warfarin n = 1, aspirin n = 3). Conclusions: Implantation of fenestrated atrial devices is feasible and effective; but the occlusion rate is high. Further research on fenestrated atrial septal devices with better long‐term patency, and effective antithrombotic drug treatment is necessary. © 2007 Wiley‐Liss, Inc.
The LightWire technology for catheter‐based interventions
Authors: Kornowski Ran , Miller Hylton I. , Shofti Rona , Lehrer Carmel , Matcovitch Avram , Sadka Elisabeth
Published: September 2007

Background: The LightWire is a newly developed opto‐acoustic coronary imaging guidewire that was designed to be used during angioplasty procedures and provide ‘online’ information on lumen and vessel wall dimensions. Methods: We designed in vitro models and performed animal trials to confirm proper device sensing capabilities and performance in the coronary arteries. This report focuses on maneuverability, compatibility with other catheterization devices, and vessel measurements. Results: Measurement ability was initially validated in vitro. Diameter measurements of coronary and peripheral arteries with and without stent based on ultrasound technology were then demonstrated in a pig model, whereas retaining easy navigation and maneuverability, as well as compatibility with other catheterization equipments. The LightWire device acquired proper and accurate multi‐location measurements of coronary and femoral artery diameters. Conclusion: Using a miniaturized opto‐acoustic technology can aid incoronary imaging, while maintaining standard guidewire performances. Thus, the LightWire device holds promise as a diagnostic and guidance tool during coronary and peripheral angioplasty procedures. © 2007 Wiley‐Liss, Inc.
Role of progenitor endothelial cells in cardiovascular disease and upcoming therapies
Authors: Kawamoto Atsuhiko , Asahara Takayuki
Published: September 2007

The field of cell‐based transplantation has expanded considerably and is poised to become an established cardiovascular therapy in the near future. In this review, we will focus on endothelial progenitor cells (EPCs), which are immature cells capable of differentiating into mature endothelial cells. EPCs share many surface marker antigens such as CD34, AC133, Flk‐1, etc. with hematopoietic stem cells (HSCs) and the major source of EPCs as well as HSCs is the bone marrow (BM). BM‐derived EPCs are mobilized into peripheral blood and recruited to the foci of pathophysiological neovascularization and reendothelialization, thereby contributing to vascular regeneration. Severe EPC dysfunction is an indicator of poor prognosis and severe endothelial dysfunction. Indeed, number of circulating EPCs and their migratory activity are reduced in patients with diabetes, coronary artery disease (CAD), or subjects with multiple coronary risk factors. Effective neovascularization induced by EPC transplantation for hindlimb, myocardial, and cerebral ischemia has been demonstrated in many preclinical studies, and early clinical trials of EPC transplantation in chronic and acute CAD indicate safety and feasibility of myocardial cell‐based therapies. For therapeutic reendothelialization in patients undergoing percutaneous coronary intervention, CD34 antibody‐coated stents have been used clinically to capture circulating EPCs at the injury sites and enhance reendothelialization and safety of stents. Further development in cell processing technology for efficient isolation, expansion, mobilization, recruitment, and transplantation of EPCs into target tissues are underway and expected to be tested in clinical trials in the near future. © 2007 Wiley‐Liss, Inc.
Highly Diastereo‐ and Enantioselective Direct Aldol Reactions of Aldehydes and Ketones Catalyzed by Siloxyproline in the Presence of Water
Authors: Aratake Seiji , Itoh Takahiko , Okano Tsubasa , Nagae Norio , Sumiya Tatsunobu , Shoji Mitsuru , Hayashi Yujiro
Published: September 2007

Proline‐based organocatalysts have been developed for a highly enantioselective, direct aldol reaction of aldehydes and ketones in the presence of water. While several surfactant–proline combined catalysts have proved effective, proline derivatives with a hydrophobic moiety such as trans‐siloxy‐L‐proline and cis‐siloxy‐D‐proline, both of which are easily prepared from the same commercially available 4‐hydroxy‐L‐proline, have been found to be the most effective organocatalysts examined in this study, affording the aldol product with excellent diastereo‐ and enantioselectivities, these two catalysts generating opposite enantiomers. Water affects the selectivity, and poor results are obtained under neat reaction conditions or in dry organic solvents. More than three equivalents of water are required for the best diastereo‐ and enantioselectivities, while three equivalents is the recommended amount from a synthetic point of view. The reaction proceeds in the organic phase, and also proceeds in the presence of a large amount of water. The large‐scale preparation of aldols with the minimal use of an organic solvent, including in the purification step, is described.
How Strong Are Hydrogen Bonds in Metalla‐β‐diketones?
Authors: Steinborn Dirk , Schwieger Sebastian
Published: September 2007

The energies of the kinetically inert, electronically saturated Lukehart‐type metalla‐β‐diketone [Re{(COMe)2H}(CO)4] (9 a) and of the kinetically labile, electronically unsaturated platina‐β‐diketones [Pt{(COMe)2H}Cl2]− (10 a), [Pt2{(COMe)2H}2(μ‐Cl)2] (11 a), and [Pt{(COMe)2H}(bpy)]+ (12 a) have been calculated by DFT at the B3LYP/6‐311++G(d,p) level using effective core potentials with consideration of relativistic effects for the transition metals. Analogously, energies of the requisite open (non‐hydrogen‐bonded) equilibrium conformers (9 b, 10 c, 11 b, 12 b) and energies which were obtained from the hydrogen‐bonded conformers by rigid rotation of the OH group around the CO bond by 180° followed by relaxation of all bond lengths and angles (9 c, 10 d, 11 c, 12 d) have been calculated. These energies were found to be higher by 14.7/27.2 (9 b/9 c), 20.7/27.2 (10 c/10 d), 19.2/25.7 (11 b/11 c), and 9.4/19.6 kcal mol−1 (12 b/12 d) than those of the intramolecularly OH⋅⋅⋅O hydrogen‐bonded metalla‐β‐diketones 9 a, 10 a, 11 a, and 12 a, respectively. In acetylacetone (Hacac), the generic organic analogue of metalla‐β‐diketones, the energies of the most stable non‐hydrogen‐bonded enol isomer (6 b) and of the conformer derived from the H‐bonded form by rigid rotation of the OH group by 180° followed by subsequent relaxation of all bond lengths and angles (6 k) were found to be 10.9/16.1 kcal mol−1 (6 b/6 k) higher compared to the intramolecularly OH⋅⋅⋅O bonded isomer 6 a. Thus, the hydrogen bonds in metalla‐β‐ diketones must be regarded as strong and were found to be up to twice as strong as that in acetylacetone. A linear relationship was found between the hydrogen‐bond energies based on the rigidly rotated structures and the O⋅⋅⋅O separation in the hydrogen‐bonded structures. Furthermore, these energies were also found to be correlated with the electron densities at the O⋅⋅⋅H bond critical points (ρbcp) in the OH⋅⋅⋅O bonds of metalla‐β‐diketones 9 a, 10 a, 11 a, and 12 a (calculated using the AIM theory). The comparison of the energies of the doubly intermolecularly hydrogen‐bonded dinuclear platina‐β‐diketone [{Pt{(COMe)2H}(bpy)}2]2+ (14) with that of the mononuclear intramolecularly hydrogen‐bonded cation [Pt{(COMe)2H}(bpy)]+ (12 a) showed that the intermolecular hydrogen bonds in 14 are weaker than the intramolecular hydrogen bond in 12.
Role of myosin II activity and the regulation of myosin light chain phosphorylation in astrocytomas
Authors: Salhia Bodour , Hwang Jeong Hyun , Smith Christian A. , Nakada Mitsutoshi , Rutka Fiona , Symons Marc , Rutka James T.
Published: September 2007

The generation of contractile force mediated by actin‐myosin interactions is essential for cell motility. Myosin activity is promoted by phosphorylation of myosin light chain (MLC). MLC phosphorylation in large part is controlled by kinases that are effectors of Rho family GTPases. Accordingly, in this study we examined the effects of ROCK and Rac1 inhibition on MLC phosphorylation in astrocytoma cells. We found that low concentrations of the ROCK inhibitor Y27632 increased the phosphorylation state of the Triton X‐100 soluble fraction of MLC, whereas higher concentrations of Y27632 decreased soluble phospho‐MLC. These effects of Y27632 were dependent on Rac1. The soluble form of phospho‐MLC comprises about 10% of total phospho‐MLC in control cells. Interestingly, ROCK inhibition led to a decrease in the phosphorylation state of total MLC, whereas Rac1 inhibition had little effect. Thus, the soluble form of MLC is differentially regulated by ROCK and Rac1 compared with MLC examined in a total cell extract. We also observed that astrocytoma migration is stimulated by low concentrations of the myosin II inhibitor blebbistatin. However, higher concentrations of blebbistatin inhibit migration leading us to believe that migration has a biphasic dependence on myosin II activity. Taken together, our data show that modulation of myosin II activity is important in determining optimal astrocytoma migration. In addition, these findings suggest that there are at least two populations of MLC that are differentially regulated. Cell Motil. Cytoskeleton 2008. © 2007 Wiley‐Liss, Inc.
Solid‐State Anion–Guest Encapsulation by Metallosupramolecular Capsules Made from Two Tetranuclear Copper(II) Complexes (Eur. J. Inorg. Chem. 29/2007)
Authors: Pardo Emilio , Bernot Kevin , Lloret Francesc , Julve Miguel , Ruiz‐García Rafael , Pasán Jorge , Ruiz‐Pérez Catalina , Cangussu Danielle , Costa Valeria , Lescouëzec Rodrigue , Journaux Yves
Published: September 2007

The cover picture shows unique examples of homo‐ and heterochiral, dimeric metal capsules resulting from the self‐assembly of two helical, bowl‐shaped tetranuclear copper(II) complexes that encapsulate different anions in the solid state, like pearls in an oyster (shown as the background). This kind of self‐assembled, coordination‐bonded motifs are a major topic in metallosupramolecular chemistry because of their binding capabilities and associated host–guest chemistry. However, their magnetic properties are largely unexplored, and here we provide one of the rare magnetic studies on these host–guest systems. For more details on the combined structural and magnetic investigations of this class of synthetic “oyster” molecules, see the article by F. Lloret, Y. Journaux et al. on page 4569 ff.
Synthesis of Tyrosine‐Derived Tetrahydroisoquinolines by Lewis Acid Catalyzed Cyclization of N‐(Phenylsulfonyl)alkyloxazolidinones
Authors: Tussetschläger Stefan , Baro Angelika , Laschat Sabine , Frey Wolfgang
Published: September 2007

N‐Boc‐protected tyrosine esters 5a,b were converted into tetrahydroisoquinolines 13 and 14 in four steps by reduction and ring closure to oxazolidinones 9 and 10, addition of benzenesulfinic acid and aldehydes to sulfones 11 and 12 and subsequent Lewis acid catalyzed cyclization. In the case of m‐tyrosine derivative 5a, selective protection with bromine prevented the formation of undesired regioisomers. Debromination of target compounds 13 was readily achieved under radical reduction conditions by using Bu3SnH/AIBN. Tetrahydroisoquinolines 13 and 14 were isolated as single diastereomers whose trans configuration was confirmed by X‐ray crystal structure analysis. Partial epimerization of trans‐13i and trans‐21 to the corresponding cis diastereomers was achieved under basic conditions. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Non‐Phenolic Dicinnamamides from Pholiota Spumosa: Isolation, Synthesis and Antitumour Activity
Authors: Clericuzio Marco , Tabasso Silvia , Garbarino Juan A. , Piovano Marisa , Cardile Venera , Russo Alessandra , Vidari Giovanni
Published: September 2007

Two new amides derived from cinnamic acid, namely,(R)‐2‐hydroxyputrescine dicinnamamide (4) and pholiotic acid {(2R)‐2‐[(S)‐3‐hydroxy‐3‐methylglutaryloxy]putrescine dicinnamamide} (5), in addition to the known compound maytenine (N1,N8‐dicinnamoyl spermidine) (3) were isolated from the fruiting bodies of the Basidiomycete Pholiota spumosa. The absolute configuration of 4 was established as (R) by its total synthesis starting from (S)‐dimethylmalate, whereas that of 5 was determined by conversion into the known compound methyl (S)‐4‐[(S)‐1‐(1‐naphthalen‐1‐yl)ethylcarbamoyl]‐3‐hydroxy‐3‐methylbutanoate (14). Compounds 3 and 5 exhibited an inhibitory effect on cell growth of the androgen‐insensitive DU‐145 prostate cancer cells, which suggests that these fungal polyamine conjugates, like other polyamine analogues, might have chemotherapeutic potential against androgen‐independent prostatic cancer. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Retipolides – Unusual Spiromacrolactones from the Mushrooms Retiboletus retipes and R. ornatipes
Authors: Justus Karl , Herrmann Rupert , Klamann Jörg‐Dieter , Gruber Gertraud , Hellwig Veronika , Ingerl Andrea , Polborn Kurt , Steffan Bert , Steglich Wolfgang
Published: September 2007

Mushrooms of the genus Retiboletus contain the retipolides A–D (1, 6–8), unusual 14‐membered spiromacrolides with a biphenyl ether linkage. The structures of these metabolites suggested a biogenetic sequence starting from retipolide E (16), which could furnish the unique 2(3H)‐oxepinone unit of retipolide C (7) via an oxidative enlargement of the 4‐hydroxyphenyl ring. A subsequent O/C‐acyl shift would then lead to the cyclopenta[c]pyran system of retipolide A (1). The proposed precursor 16 was synthesized and subsequently detected in the fungal extract in addition to the probable biosynthetic intermediates butyrolactone II (13), tyrosol (14), and secoretipolide E (15). The structural elucidation of retipolide A (1) was accomplished after transformation into a methoxyfulvene derivative 2a, and the absolute (R) configuration of 1 was assigned by a single‐crystal X‐ray analysis of the corresponding (S)‐sec‐butoxyfulvene analogue 2b. Some samples of R. retipes/ornatipes contained isoretipolide A (9), an isomer of 1 with a highly strained 12‐membered lactone ring incorporating two C,C‐coupled 4‐hydroxyphenyl units. A comparison of the CD spectrum of retipolide A (1) with those of the other retipolides and isoretipolide A (9) indicates that all of these macrolides possess R configuration. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Expedient Syntheses of β‐Iodofurans by 5‐endo‐dig Cyclisations
Authors: Bew Sean P. , El‐Taeb Gamila M. M. , Jones Simon , Knight David W. , Tan Wen‐Fei
Published: September 2007

5‐endo‐dig cyclisations of 3‐alkyne‐1,2‐diols using iodine as the electrophile proceed smoothly to deliver excellent yields of the corresponding β‐iodofurans. The necessary precursors are available from a number of different approaches, notably regioselective bis‐hydroxylation of conjugated enynes and the addition of acetylides to α‐hydroxy carbonyl groups. The initial iodofurans can be homologated using a number of strategies, ranging from various transition metal‐catalysed couplings to halogen–metal exchange and subsequent coupling with an electrophile. Hence, this method overall represents a flexible, relatively brief and very efficient approach to a variety of highly substituted furans. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Synthesis of Pyrrolidine‐Based Imino Sugars as Glycosidase Inhibitors
Authors: Doddi Venkata Ramana , Vankar Yashwant D.
Published: September 2007

Two pyrrolidine‐based imino sugars have been synthesized in an efficient manner, using regiospecific amination, ring closing metathesis, and diastereospecific dihydroxylations as key steps. These azasugars are found to be moderate inhibitors of glycosidases. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Isocratic Liquid Chromatography with Segmented Columns and Simultaneous UV and Dual Electrochemical Detection: Application to the Selectivity Enhancement for the Determination of Explosives
Authors: Matysik Frank‐Michael , Schumann Ulrike , Engewald Werner
Published: September 2007

The concept of stationary‐phase optimized liquid chromatography (POPLC) was studied in the context of separation and detection aspects for the determination of explosives. A tailor‐made segmented column assembly with three complementary reverse‐phase materials enabled the separation of 14 priority target nitroaromatic explosives. This experimental approach resulted in excellent selectivity without using gradient‐elution protocols which can considerably deteriorate the performance of electrochemical detection. Consequently, the POPLC separations could be operated under isocratic conditions which were very important for the reliable use of electrochemical detection. Simultaneous UV and dual electrochemical detection resulting in three detection traces was exploited as an additional means for the further enhancement of selectivity in more complex samples.
Nonaqueous CE using contactless conductivity detection and ionic liquids as BGEs in ACN
Authors: Borissova Maria , Gorbatšova Jelena , Ebber Arkadi , Kaljurand Mihkel , Koel Mihkel , Vaher Merike
Published: September 2007

N,N′‐Alkylmethylimidazolium cations have been separated in NACE when one of the N,N′‐dialkylimidazolium salts (ionic liquids (ILs)) was used as an electrolyte additive to the organic solvent separation medium. The separated species were 1‐methyl‐, 1‐ethyl‐, 1‐butyl‐, 1‐octyl‐, 1‐decyl‐3‐methylimidazolium and N‐butyl‐3‐methylpyridinium cations and BGE composed of 1‐ethyl‐3‐methylimidazolium ethylsulfate or 1‐butyl‐3‐methylimidazolium trifluoroacetate [BMIm][FAcO] (A6; B2) diluted in ACN. It was demonstrated that contactless conductivity detection (CCD) may be applied to monitoring the separation process in nonaqueous separation media, allowing to use the UV light‐absorbing imidazolium‐based electrolyte additives. There could be marked three concentration regions of added ILs; at first ionic strength of BGE below 1–2 mM, and then the actual electrophoretic mobility of analytes rises from 0. At concentrations above 1–2 mM, the added IL facilitated separation. In concentration region of 1–20 mM, the actual electrophoretic mobility of analyzed imidazolium cations was increasing with decrease in separation medium ionic strength. At higher concentrations of BGE (above 30 mM), the conductivity of the separation media became too high for this detector. Some organic dyes were also successfully separated and detected by contactless conductivity detector in a 20 mM A6 separation electrolyte in ACN.
CE of tricyclic antidepressant clomipramine and metabolites: Electromigration and wall adsorption
Authors: Martello Rita , Kolivoska Viliam , Raggi Maria Augusta , Kenndler Ernst
Published: September 2007

CE of tricyclic antidepressants clomipramine and its metabolites demethylclomipramine, didemethylclomipramine and 8‐hydroxyclomipramine resulted in partly extremely tailing peaks in bare fused‐silica capillaries. Especially at high pH of the BGE this behavior was not unexpected as adsorption of the cationic analytes onto the negatively charged wall due to electrostatic attraction can be supposed. Less expected was the observation that peak tailing could not be overcome neither by using a capillary with dynamic coating with cationic CTAB added to the BGE, nor by the usage of a capillary permanently coated with polyvinyl alcohol (PVA), both operated at acidic pH. As this tailing was even more pronounced than with bare fused silica, and was suppressed upon addition of MeCN to the BGE, another source of adsorption than pure ion–ion interaction seems plausible. In the bare silica capillary the mobility, μ, of the analytes followed roughly the pH dependence of a monoacidic base, but two deviations from the sigmoid theoretical curve were evident: (i) even at low pH the mobilities were not constant; they decreased in contrary with pH over the entire range; (ii) the apparent pKa values of two analytes, derived at the pH with halve the mobility at low pH, are significantly smaller than the thermodynamic pKa. Upon modifying the expression for μ = f(pH), and considering the pH dependence of the negative charge density at the wall by an additional term which takes chromatographic retention into account, an equation was derived which enables the description of the observed electromigration of the analytes as function of pH, pKa of analytes and surface silanol groups, actual mobility of analytes, distribution coefficient (or retention factor) due to adsorption including its pH dependence. The interplay of electrophoretic movement and residual adsorptive retention allowed to resolve the analytes finally in an uncoated capillary, namely at pH 7.65 (30 mM ionic strength), whereas at the cost of the robustness of the separation system.
Effect of detergent on electromigration of proteins: CE of very low density lipoprotein receptor modules and viral proteins
Authors: Kremser Leopold , Bilek Gerhard , Kenndler Ernst
Published: September 2007

The different electrophoretic behavior of the members of two groups of proteins with respect to the absence or presence of detergent additives in the BGE was explored. Recombinant soluble concatemers of repeat 3 of the very low density lipoprotein (VLDL)‐receptor fused at their N‐terminus to maltose‐binding protein (MBP) exhibited different electrophoretic mobilities in borate buffer (pH 8.3) in the absence and in the presence of dodecyl‐PEG ether (D‐PEG). This enabled the separation of the receptor fragments from MBP after enzymatic cleavage. In the presence of SDS, the mobilities of all proteins approached the same values with increase in detergent concentrations. In contrast, viral capsid proteins of a human rhinovirus (HRV) exhibited different migration in the presence of the additive. For the receptor proteins, extreme apparent high plate numbers were observed when the SDS concentration in the sample and the separation buffer differed. This effect might be erroneously interpreted as a high efficiency. However, it is due to the conductivity boundaries caused by the sample and leads to a total loss of separation.
Sensitive determination of herbicides in food samples by nonaqueous CE using pressurized liquid extraction
Authors: Carabias‐Martínez Rita , Rodríguez‐Gonzalo Encarnacion , Miranda‐Cruz Edith , Domínguez‐Álvarez Javier , Hernández‐Méndez Jesus
Published: September 2007

We have developed a method involving extraction with mixtures of solvents under pressure (pressurized liquid extraction (PLE)) for the determination of triazine herbicides in a series of samples from the food industry. The organic extracts obtained were subjected to a clean‐up step with SPE, using Oasis MCX® sorbents, after which they were analyzed by NACE. Potato was chosen as a representative matrix of horticultural products since it has a high water content. Spiked potato samples were used to optimize extraction conditions. In order to compare the results obtained with NACE, different studies were also conducted using HPLC. The detection limits in NACE were similar to those found with HPLC and were of the order of 10–15 μg/kg, depending on the analyte. Satisfactory results were obtained on applying the method proposed for the potato matrix (PLE with separation by electrophoresis) to other food matrices such as other tubercles, fruits, vegetables and cereals.
Separation of corticosteroids by microemulsion EKC with diethyl L‐tartrate as the oil phase
Authors: Wu Chi‐Hung , Chen Tse‐Hsien , Huang Kuan‐Pin , Wang Guan‐Ren , Liu Chuen‐Ying
Published: September 2007

A novel microemulsion based on a mixture of diethyl L‐tartrate (DET) and SDS was developed for the microemulsion EKC (MEEKC) determination of structurally related steroids. The system consisted of 0.5% w/w DET, 1.7% w/w SDS, 1.2% w/w 1‐butanol, 89.6% w/w phosphate buffer (40 mM, pH 7.0), and 7% w/w ACN. With an applied voltage of +10 kV, a baseline separation of aldosterone (A), cortisone acetate (CA), dexamethasone (D), hydrocortisone (H), hydrocortisone acetate (HA), prednisolone (P), prednisolone acetate (PA), prednisone (Ps), triamcinolone (T), and triamcinolone acetonide (TA) could be achieved. Under the optimized conditions, the reproducibility of the retention time (n = 4) for most of the compounds was less than ±0.8% with the exception of  A, Ps, and T. The average number of theoretical plates was 18 800 plates/m. The results were compared with those achieved by the modified micellar EKC (MEKC). MEEKC showed obvious advantages over MEKC for the separation of highly hydrophobic substances. To further evaluate the system, we tested the MEEKC method by analyzing corticosteroids in a spiked urine sample.
Comparison of computational times and accuracy for finite element solution of Navier–Stokes equations and Ladyzhenskaya equations
Authors: Fairag Faisal A.
Published: September 2007

In this paper we consider a pure‐streamfunction equation of the Ladyzhenskaya equations. For certain values of the parameters of the equation, the studied equation becomes identical to the pure‐streamfunction equation of the Navier–Stokes equations. A weak form, a finite element method approximation procedures, and an iterative method for solving the discrete nonlinear problems are provided. Using the Bogner–Fox–Schmidt element, the steady 2‐D incompressible flow in a driven cavity is solved using a grid mesh of 16 × 16. Streamfunction contours are also displayed showing the main features of the flow. Copyright © 2007 John Wiley & Sons, Ltd.
A method to discretize non‐planar fractures for 3D subsurface flow and transport simulations
Authors: Graf Thomas , Therrien René
Published: September 2007

A method is presented to discretize inclined non‐planar 2D fractures within a 3D finite element grid for subsurface flow and transport simulations. Each 2D fracture is represented as a triangulated surface. Each triangle is then discretized by 2D fracture elements that can be horizontal, vertical or inclined and that can be triangular or rectangular. The 3D grid representing a porous rock formation consists of hexahedra and can be irregular to allow grid refinement. An inclined fracture was discretized by (a) inclined triangles and (b) orthogonal rectangles and flow/transport simulations were run to compare the results. The comparison showed that (i) inclined fracture elements must be used to simulate 2D transient flow, (ii) results of 2D/3D steady‐state and 3D transient flow simulations are identical for both discretization methods, (iii) inclined fracture elements must be used to simulate 2D/3D transport because orthogonal fracture elements significantly underestimate concentrations, and (iv) orthogonal elements can be used to simulate 2D/3D transport if fracture permeability is corrected and multiplied by the ratio of fracture surface areas (orthogonal to inclined). Groundwater flow at a potential site for long‐term disposal of spent nuclear fuel was simulated where a complex 3D fracture network was discretized with this technique. The large‐scale simulation demonstrates that the proposed discretization procedure offers new possibilities to simulate flow and transport in complex 3D fracture networks. The new procedure has the further advantage that the same grid can be used for different realizations of a fracture network model with no need to regenerate the grid. Copyright © 2007 John Wiley & Sons, Ltd.
The timing of cognitive control in partially incongruent categorization
Authors: Chen Antao , Xu Peng , Wang Quanhong , Luo Yuejia , Yuan Jiajin , Yao Dezhong , Li Hong
Published: September 2007

We designed a novel task, partially incongruent categorization (PIC), to examine the timing of cognitive control. In the PIC task, participants categorized the probe stimulus according to a specific concept, and the number of features corresponding to the concept was varied. When there was one feature (c1 condition), the probe would elicit only categorization, but when there was more than one feature (c2 and c3 conditions), the probe would also elicit cognitive control. Here, the high temporal resolution of event‐related potentials (ERPs) was utilized to investigate the temporal patterns of activity during conflict detection and control. Cognitive control elicited a N2 that was much larger in response to c2 and c3 than c1 in stimulus‐locked waveforms, and no difference was evident between c2 and c3. The N2 was followed by a P3 that was much less on c2 and c3 than c1 trials, with no difference between c2 and c3. A dipole source analysis for two difference waves, c2−c1 and c3−c1, further showed that the corresponding dipoles of the N2 and P3 in the cognitive control conditions were in the anterior cingulate cortex (ACC) and prefrontal cortex (PFC), respectively. Taken together, the present findings support that ERP components in response to the PIC task reflect the time course of cognitive control: the N2 responds to conflict information and subsequently activates the P3 to control this conflict. The connection between the ACC and PFC is supported by their sequential activation within trials. Hum Brain Mapp, 2008. © 2007 Wiley‐Liss, Inc.
The neural bases of attentive reading
Authors: Jung Julien , Mainy Nelly , Kahane Philippe , Minotti Lorella , Hoffmann Dominique , Bertrand Olivier , Lachaux Jean‐Philippe
Published: September 2007

Recent studies have suggested that attention facilitates the formation of synchronous neural assemblies in the γ range (>40 Hz) to amplify behaviorally relevant signals. Whether this mechanism is general or confined to sensory cortices is still a matter of debate, since there is little evidence of a direct link between attention and increased γ synchronization in high‐level brain regions. We recorded the intracerebral EEG of 10 epileptic patients while manipulating their attention during reading, and compared the neural responses to attended and unattended words. Visual presentation of attended words induced γ band responses in the major brain regions associated with reading and those responses were attenuated for unattended words. The attenuation was not uniform within the reading network but followed a gradient from the posterior visual to the frontal areas. Altogether, these results support the view that the γ band response can be used as a quantitative marker of attention. Hum Brain Mapp 2008. © 2007 Wiley‐Liss, Inc.
An fMRI study on memory discriminability for complex visual scenes
Authors: Blondin François , Lepage Martin
Published: September 2007

The fan effect represents an increase in reaction time for the recognition of an item as a function of the amount of information associated with that item in memory. The present study used fMRI to study the neural correlates of the fan effect for complex visual scenes. We used a test in which landscape pictures were divided vertically into three equal segments. In the high discriminability condition only one segment was presented during encoding, whereas in the low discriminability condition two different segments from the same picture were presented. During a subsequent forced‐choice recognition test, reaction times were significantly faster for the high discriminability condition. Increase in brain activity for the low relative to high discriminability condition was observed in the right prefrontal cortex, several regions of parietal cortex bilaterally, and several late visual processing areas, including the occipito‐temporal regions, precuneus, and cuneus. These results support the hypothesis that a region of the prefrontal cortex is involved in the control of memory interference at retrieval elicited by the amount of related information in memory, and further suggests that this involvement is right‐lateralized for nonverbal material. The high versus low discriminability contrast showed an increase in activity principally in the bilateral medial temporal gyrus, including the enthorinal cortex/hippocampus and in several bilateral prefrontal cortex regions mostly located in BA 10. These activations were associated with a condition, in which the stimuli were more salient in memory and thus could represent the perceptual salience of items in memory. Hum Brain Mapp, 2008. © 2007 Wiley‐Liss, Inc.
Temporal lobe and “default” hemodynamic brain modes discriminate between schizophrenia and bipolar disorder
Authors: Calhoun Vince D. , Maciejewski Paul K. , Pearlson Godfrey D. , Kiehl Kent A.
Published: September 2007

Schizophrenia and bipolar disorder are currently diagnosed on the basis of psychiatric symptoms and longitudinal course. The determination of a reliable, biologically‐based diagnostic indicator of these diseases (a biomarker) could provide the groundwork for developing more rigorous tools for differential diagnosis and treatment assignment. Recently, methods have been used to identify distinct sets of brain regions or “spatial modes” exhibiting temporally coherent brain activity. Using functional magnetic resonance imaging (fMRI) data and a multivariate analysis method, independent component analysis, we combined the temporal lobe and the default modes to discriminate subjects with bipolar disorder, chronic schizophrenia, and healthy controls. Temporal lobe and default mode networks were reliably identified in all participants. Classification results on an independent set of individuals revealed an average sensitivity and specificity of 90 and 95%, respectively. The use of coherent brain networks such as the temporal lobe and default mode networks may provide a more reliable measure of disease state than task‐correlated fMRI activity. A combination of two such hemodynamic brain networks shows promise as a biomarker for schizophrenia and bipolar disorder. Hum Brain Mapp 2008. © 2007 Wiley‐Liss, Inc.
Validation of a method for coregistering scalp recording locations with 3D structural MR images
Authors: Whalen Christopher , Maclin Edward L. , Fabiani Monica , Gratton Gabriele
Published: September 2007

A common problem in brain imaging is how to most appropriately coregister anatomical and functional data sets into a common space. For surface‐based recordings such as the event related optical signal (EROS), near‐infrared spectroscopy (NIRS), event‐related potentials (ERPs), and magnetoencephalography (MEG), alignment is typically done using either (1) a landmark‐based method involving placement of surface markers that can be detected in both modalities; or (2) surface‐fitting alignment that samples many points on the surface of the head in the functional space and aligns those points to the surface of the anatomical image. Here we compare these two approaches and advocate a combination of the two in order to optimize coregistration of EROS and NIRS data with structural magnetic resonance images (sMRI). Digitized 3D sensor locations obtained with a Polhemus® digitizer can be effectively coregistered with sMRI using fiducial alignment as an initial guess followed by a Marquardt–Levenberg least‐squares rigid‐body transform (df = 6) to match the surfaces. Additional scaling parameters (df = 3) and point‐by‐point surface constraints can also be employed to further improve fitting. These alignment procedures place the lower‐bound residual error at 1.3 ± 0.1 mm (μ ± s) and the upper‐bound target registration error at 4.4 ± 0.6 mm (μ ± s). The dependence of such errors on scalp segmentation, number of registration points, and initial guess is also investigated. By optimizing alignment techniques, anatomical localization of surface recordings can be improved in individual subjects. Hum Brain Mapp, 2008. © 2007 Wiley‐Liss, Inc.
Peginterferon alfa-2b and weight-based or flat-dose ribavirin in chronic hepatitis C patients
Authors: Jacobson Ira M. , Brown Robert S. , Freilich Bradley , Afdhal Nezam , Kwo Paul Y. , Santoro John , Becker Scott , Wakil Adil E. , Pound David , Godofsky Eliot , Strauss Robert , Bernstein David , Flamm Steven , Pauly Mary Pat , Mukhopadhyay Pabak , Griffel Louis H. , Brass Clifford A.
Published: September 2007

This prospective, multicenter, community-based and academic-based, open-label, investigator-initiated, U.S. study evaluated efficacy and safety of pegylated interferon (PEG-IFN) alfa-2b plus a flat or weight-based dose of ribavirin (RBV) in adults with chronic hepatitis C. Patients (n = 5027) were randomly assigned to receive PEG-IFN alfa-2b 1.5 μg/kg/week plus flat-dose (800 mg/day) or weight-based (800-1400 mg/day) RBV for 48 weeks (patients with genotype 1, 4, 5, or 6) and for 24 or 48 weeks (genotype 2/3 patients). Primary end point was sustained virologic response (undetectable [<125 IU/mL] serum hepatitis C virus RNA at 24-week follow-up). Sustained virologic response, but not end-of-treatment, rates were significantly higher with weight-based than with flat-dose RBV (44.2% versus 40.5%;

P

= 0.008). Sustained virologic response rates by intention-to-treat analysis were 34.0% and 28.9%, respectively, in genotype 1 patients (

P

= 0.005) and 31.2% and 26.7%, respectively, in genotype 1 patients with high baseline viral load (

P

= 0.056). In genotype 2/3 patients, rates were not significantly different (61.8% and 59.5%, respectively) regardless of treatment duration. Besides greater hemoglobin reductions with weight-based RBV, safety profiles were similar across RBV dosing groups, including the 1400-mg/day group.

Conclusion:

PEG-IFN alfa-2b plus weight-based RBV is more effective than flat-dose RBV, particularly in genotype 1 patients, providing equivalent efficacy across all weight groups. RBV 1400 mg/day is appropriate for patients 105 to 125 kg. For genotype 2/3 patients, 24 weeks of treatment with flat-dose RBV is adequate; no evidence of additional benefit of extending treatment to 48 weeks was demonstrated. (HEPATOLOGY 2007;46:971–981.)
Classical Benzotriazole‐Mediated α‐Aminoalkylations of Alkynes: Synthesis and Characterization of Alk‐2‐yn‐1‐amines as Amphiphilic Materials
Authors: Idzik Krzysztof R. , Cabaj Joanna , Sołoducho Jadwiga , Abdel‐Fattah Ashraf A. A.
Published: September 2007

Reactions of readily available and stable benzotriazolemethanamines 1a–l, obtained from aldehydes and secondary amines (Scheme 2), gave the expected alk‐2‐yn‐1‐amines 3a–t (Scheme 3). The amphiphilic character of the synthesized products was responsible for physicochemical measurements. Specific aggregation properties of the obtained compounds make them useful as electroactive materials in the Langmuir–Blodgett technique.
Sesquiterpenoids from the Rhizome of Ligularia virgaurea
Authors: Sun Xiao‐Bai , Xu Yang‐Jun , Qiu Dong‐Feng , Yuan Cheng‐Shan
Published: September 2007

Two novel sesquiterpene dimers, compounds 1 and 2, were isolated from the rhizome of Ligularia virgaurea, together with the six known sesquiterpenoids 3–8. Their structures were established by physico‐chemical and spectroscopic methods, especially by means of 1D‐ and 2D‐NMR as well as HR‐MS analyses. A mechanism based on a classical Diels–Alder cyclization is proposed for the formation of the dimer 1 from the precursors 8 and the quinone form of 6 (Scheme).
A Facile One‐Pot Synthesis of Functionalized 1,5‐Dihydro‐2H‐[1]benzopyrano[2,3‐b]pyridin‐5‐ones
Authors: Esmaeili Abbas Ali , Ghareghani Omid
Published: September 2007

The highly reactive 1 : 1 intermediate generated in the reaction between dialkyl acetylenedicarboxylate (=but‐2‐ynedioic acid dialkyl ester) 4 and triphenylphosphine was trapped by 2‐amino‐4‐oxo‐4H‐1‐benzopyran‐3‐carboxaldehydes 5 to yield highly functionalized dialkyl‐1,5‐dihydro‐5‐oxo‐1‐phenyl‐2H‐[1]benzopyrano[2,3‐b]pyridine‐2,3‐dicarboxylates in high yield.
Synthesis and Transformation of Methyl 2‐(6‐Hydroxy‐2‐phenylpyrimidin‐4‐yl)acetate: Simple Preparation of Pyrimidines with Heterocyclic Substituents
Authors: Bevk David , Grošelj Uroš , Meden Anton , Svete Jurij , Stanovnik Branko
Published: September 2007

A simple and efficient synthesis of four new substituted pyrimidines, compounds 9a–d, from the title compound 3 is described. Conversion of 3 to methyl (E)‐3‐(dimethylamino)‐2‐(6‐methoxy‐2‐phenylpyrimidin‐4‐yl)prop‐2‐enoate (4), followed by condensation with various dinucleophiles according to the ‘enaminone methodology’, afforded the target compounds 9 in medium‐to‐good yields.
Novel Bis(bibenzyl) and (Propylphenyl)bibenzyl Derivatives from Dendrobium nobile
Authors: Liu Qun‐Fang , Chen Wen‐Liang , Tang Jian , Zhao Wei‐Min
Published: September 2007

Two novel compounds possessing a bis(bibenzyl) (see 1) and a (propylphenyl)bibenzyl skeleton (see 2) and eight known compounds were isolated from the stems of Dendrobium nobile Lindl. (Orchidaceae). Their structures were identified by spectroscopic analyses.
Phenylpropanoid‐Substituted Catechins and Epicatechins from Smilax china
Authors: Huang Hui‐Lian , Lu Zhi‐Qiang , Chen Guang‐Tong , Zhang Jin‐Qiang , Wang Wei , Yang Min , Guo De‐An
Published: September 2007

The four new phenylpropanoid‐substituted catechins 1, 3, and 4 and 3‐epicatechin (2), together with seven analogues, were isolated from the AcOEt extract of Smilax china L. (catechin=(2R,3S)‐2‐(3,4‐dihydroxyphenyl)‐3,4‐dihydro‐2H‐2‐benzopyran‐3,5,7‐triol). Their structures were determined by means of spectroscopic analyses, including HR‐MS, IR, 1H‐ and 13C‐NMR, and 2D experiments (COSY, HSQC, and HMBC), and comparison with known related compounds.
The First Reaction of Dimethoxycarbene with an Imine Moiety
Authors: Mlostoń Grzegorz , Heimgartner Heinz
Published: September 2007

The nucleophilic dimethoxycarbene (DMC; 2) generated by thermal decomposition of 2,5‐dihydro‐1,3,4‐oxadiazole derivative 1 in boiling toluene reacts smoothly with N‐(9H‐fluoren‐9‐ylidene)‐4‐methylbenzenesulfonamide (7b) to yield carbonimidoate derivative 10. A multi‐step reaction pathway, initiated by the attack of DMC onto the CN bond and followed by the migration of the sulfonyl group (or via a sulfinate anion) is proposed to explain the formation of the final product. In contrast to the formal ketimine 7b, N‐benzylidene‐4‐methylbenzenesulfonamide (7a), a formal aldimine, does not react with DMC under comparable conditions.
Synthesis of New Bis‐imidazole Derivatives
Authors: Jasiński Marcin , Mlostoń Grzegorz , Mucha Paulina , Linden Anthony , Heimgartner Heinz
Published: September 2007

The reaction of aldimines with α‐(hydroxyimino) ketones of type 10 (1,2‐diketone monooximes) was used to prepare 2‐unsubstituted imidazole 3‐oxides 11 bearing an alkanol chain at N(1) (Scheme 2, Table 1). These products were transformed into the corresponding 2H‐imidazol‐2‐ones 13 and 2H‐imidazole‐2‐thiones 14 by treatment with Ac2O and 2,2,4,4‐tetramethylcyclobutane‐1,3‐dithione, respectively (Scheme 3). The three‐component reaction of 10, formaldehyde, and an alkane‐1,ω‐diamine 15 gave the bis[1H‐imidazole 3‐oxides] 16 (Scheme 4, Table 2). With Ac2O, 2,2,4,4‐tetramethylcyclobutane‐1,3‐dithione or Raney‐Ni, the latter reacted to give the corresponding bis[2H‐imidazol‐2‐ones] 19 and 20, bis[2H‐imidazol‐2‐thione] 21, and bis[imidazole] 22, respectively (Schemes 5 and 6). The structures of 11a and 16b were established by X‐ray crystallography.