bluuebunny/crossref_metadata_2025_split huggingface dataset:
Inhibitors of Protein Tyrosine Phosphatases: Next‐Generation Drugs?
Authors: Bialy Laurent , Waldmann Herbert 
Published: May 2005

AbstractThe protein tyrosine phosphatases (PTPs) constitute a family of closely related key regulatory enzymes that dephosphorylate phosphotyrosine residues in their protein substrates. Malfunctions in PTP activity are linked to various diseases, ranging from cancer to neurological disorders and diabetes. Consequently, PTPs have emerged as promising targets for therapeutic intervention in recent years. In this review, general aspects of PTPs and the development of small‐molecule inhibitors of PTPs by both academic research groups and pharmaceutical companies are discussed. Different strategies have been successfully applied to identify potent and selective inhibitors. These studies constitute the basis for the future development of PTP inhibitors as drugs.
Underexpansion of sirolimus‐eluting stents: Incidence and relationship to delivery pressure
Authors: Cheneau Edouard , Satler Lowell F. , Escolar Esteban , Suddath William O. , Kent Kenneth M. , Weissman Neil J. , Waksman Ron , Pichard Augusto D. 
Published: May 2005

AbstractWe aimed to assess the incidence of underexpansion and the relationship between delivery pressure and expansion with sirolimus‐eluting stents. Adequate stent expansion contributes to early and late improved outcomes. In 51 patients (53 lesions) with native coronary artery narrowing, balloon‐expandable sirolimus‐eluting stents (Cypher) were serially expanded with gradual balloon inflations [14 atm, 20 atm, and in case of minimal stent cross‐sectional area (CSA)/reference lumen CSA < 50% at 20 atm, postdilatation with 0.5 mm larger balloon]. Intravascular ultrasound (IVUS) imaging was performed before intervention and after each gradual balloon inflation. Stent expansion (minimal stent CSA/reference lumen CSA) was measured. Stent expansion was 72% ± 16% after 14 atm balloon inflation, 90% ± 18% after 20 atm balloon inflation (P < 0.001 vs. 14 atm), and 90% ± 18% at the end of the procedure (including optional postdilatations with 0.5 mm larger balloon; P = NS vs. 20 atm). Stent expansion addressed by MUSIC criteria (all struts apposed, no tissue protrusion, and final lumen CSA > 80% of the reference or > 90% if minimal lumen CSA was < 9 mm2) was adequate in 15% of the cases after 14 atm balloon inflation, in 60% after 20 atm balloon inflation (P < 0.001 vs. 14 atm), and in 60% at the end of the procedure (P = NS vs. 20 atm). Sirolimus‐eluting stent underexpansion is common when deployed at conventional pressures. Increasing balloon delivery pressure or assessing stent expansion with IVUS seems warranted in order to ensure adequate sirolimus‐eluting stent deployment. © 2005 Wiley‐Liss, Inc.
Emergency stent graft deployment for acute aortic rupture following primary stenting for aortic coarctation
Authors: Tan Ju‐Le , Mullen Michael 
Published: May 2005

AbstractWe present a case of endovascular stenting for aortic recoarctation complicated by acute aortic rupture, which was successfully treated by emergency stent graft deployment. This case illustrates the potential serious complication that can occur during aortic stent dilatation and how the prompt deployment of a stent graft helped to change the clinical outcome of this life‐threatening situation. © 2005 Wiley‐Liss, Inc.
Fluoroscopic localization of the femoral head as a landmark for common femoral artery cannulation†
Authors: Garrett Paul D. , Eckart Robert E. , Bauch Terry D. , Thompson Christopher M. , Stajduhar Karl C. 
Published: May 2005

AbstractWe sought to determine the reliability of frequently used landmarks for femoral arterial access in patients undergoing cardiac catheterization. The common femoral artery (CFA) is the most frequently used arterial access in cardiac catheterization. Arterial sheath placement into the CFA has been shown to decrease vascular complications. Some authors recommend locating the inferior border of the femoral head using fluoroscopy due to the relationship of the femoral head and the bifurcation of the CFA. We performed a descriptive study in a prospective design of 158 patients undergoing catheterization from the femoral approach. A femoral angiogram was performed, and the CFA bifurcation location was recorded in relation to the inguinal ligament, middle and inferior border of the femoral head, and the inguinal skin crease. The CFA bifurcation was distal to the inguinal ligament, middle femoral head, and inferior femoral head in most patients with mean distances (cm ± SD) of 7.5 ± 1.7, 2.9 ± 1.5, and 0.8 ± 1.2, respectively. The inguinal skin crease was below the bifurcation in 78% of patients (−1.8 ± 1.6 cm). The CFA overlies the femoral head in 92% of cases. The femoral head has a consistent relationship to the CFA, and localization using fluoroscopy is a useful landmark. © 2005 Wiley‐Liss, Inc.
Technical details and programming guide for a general two‐way positive matrix factorization algorithm
Authors: Lu Jianhang , Wu Laosheng 
Published: May 2005

AbstractIn the past decade a factor analysis model named positive matrix factorization (PMF) has been increasingly used in analysis of environmental data. The PMF computing program is commercially available from its developer, but the technical details of the algorithm and program codes remain unpublished so far. For better documentation and facilitation of its application we present the technical details of a general two‐way PMF algorithm and provide a detailed guide for its programming. We explicitly explain the iterative procedure and construction of matrices and vectors used in the PMF algorithm and illustrate their implementations with ready‐to‐use Matlab codes. We also give our experiences and suggestions on various aspects of PMF programming, such as reducing memory need, improving computational efficiency and adjusting model parameters. The contents presented in this paper are helpful for one who would like to create his/her own PMF computing codes and thus be able to tailor the model for specific tasks or purposes. Copyright © 2005 John Wiley & Sons, Ltd.
A comparative study of linear regression methods in noisy environments
Authors: Reis Marco S. , Saraiva Pedro M. 
Published: May 2005

AbstractWith the development of measurement instrumentation methods and metrology, one is very often able to rigorously specify the uncertainty associated with each measured value (e.g. concentrations, spectra, process sensors). The use of this information, along with the corresponding raw measurements, should, in principle, lead to more sound ways of performing data analysis, since the quality of data can be explicitly taken into account. This should be true, in particular, when noise is heteroscedastic and of a large magnitude. In this paper we focus on alternative multivariate linear regression methods conceived to take into account data uncertainties. We critically investigate their prediction and parameter estimation capabilities and suggest some modifications of well‐established approaches. All alternatives are tested under simulation scenarios that cover different noise and data structures. The results thus obtained provide guidelines on which methods to use and when. Interestingly enough, some of the methods that explicitly incorporate uncertainty information in their formulations tend to present not as good performances in the examples studied, whereas others that do not do so present an overall good performance. Copyright © 2005 John Wiley & Sons, Ltd.
A new maximum entropy‐based method for deconvolution of spectra with heteroscedastic noise
Authors: Buttingsrud Bård , Alsberg Bjørn K. 
Published: May 2005

AbstractBroadening of spectral lines combined with large and heteroscedastic noise contributions constitutes an important problem in analytical chemistry. Reduced interpretability and artefacts in further data analysis make deconvolution methods necessary. A new robust deconvolution method (RHEMEM) based on the principle of maximum entropy is proposed in order to effectively handle the presence of heteroscedastic noise. Other deconvolution methods such as Jansson's method, Fourier self‐deconvolution and LOMEP are also studied with respect to their ability to handle heteroscedastic noise. A systematic simulation study is used to compare the performance of the new method with the reference methods. They are evaluated according to reconstruction performance, robustness and the ability to work without manual input. Copyright © 2005 John Wiley & Sons, Ltd.
Controlling coverage of D‐optimal onion designs and selections
Authors: Olsson Ing‐Marie , Gottfries Johan , Wold Svante 
Published: May 2005

AbstractStatistical molecular design (SMD) is a powerful approach for selection of compound sets in medicinal chemistry and quantitative structure–activity relationships (QSARs) as well as other areas. Two techniques often used in SMD are space‐filling and D‐optimal designs. Both on occasions lead to unwanted redundancy and replication. To remedy such shortcomings, a generalization of D‐optimal selection was recently developed. This new method divides the compound candidate set into a number of subsets (‘layers’ or ‘shells’), and a D‐optimal selection is made from each layer. This improves the possibility to select representative molecular structures throughout any property space independently of requested sample size. This is important in complex situations where any given model is unlikely to be valid over the whole investigated domain of experimental conditions. The number of selected molecules can be controlled by varying the number of subsets or by altering the complexity of the model equation in each layer and/or the dependency of previous layers. The new method, called D‐optimal onion design (DOOD), will allow the user to choose the model equation complexity independently of sample size while still avoiding unwarranted redundancy. The focus of the present work is algorithmic improvements of DOOD in comparison with classical D‐optimal design. As illustrations, extended DOODs have been generated for two applications by in‐house programming, including some modifications of the D‐optimal algorithm. The performances of the investigated approaches are expected to differ depending on the number of principal properties of the compounds in the design, sample sizes and the investigated model, i.e. the aim of the design. QSAR models have been generated from the selected compound sets, and root mean squared error of prediction (RMSEP) values have been used as measures of performance of the different designs. Copyright © 2005 John Wiley & Sons, Ltd.
Polystyrene‐Supported Organotin Dichloride as a Recyclable Catalyst in Lactone Ring‐Opening Polymerization: Assessment and Catalysis Monitoring by High‐Resolution Magic‐Angle‐Spinning NMR Spectroscopy
Authors: Deshayes Gaëlle , Poelmans Kevin , Verbruggen Ingrid , Camacho‐Camacho Carlos , Degée Philippe , Pinoie Vanja , Martins José C. , Piotto Martial , Biesemans Monique , Willem Rudolph , Dubois Philippe 
Published: May 2005

AbstractDialkyltin dichloride grafted to a cross‐linked polystyrene, with the formula [PH](1−t)[P(CH2)nSnBuCl2]t (P=[CH2CH(pC6H4)], t=the degree of functionalization, and n=6 or 11), is investigated as a recyclable catalyst in the ring‐opening polymerization (ROP) of ε‐caprolactone (CL). It is demonstrated that high‐resolution magic‐angle‐spinning (HR‐MAS) NMR spectroscopy is an invaluable tool to characterize completely the supported catalyst. The 2D 1H–13C HSQC HR‐MAS spectrum, in particular, allowed extensive assignment of the 1H and 13C resonances, as well as accurate measurement of the nJ(1H–117/119Sn) and nJ(13C–117/119Sn) coupling constants. 1H and 119Sn HR‐MAS NMR spectroscopy is presented as a monitoring tool for catalytic processes based on organotin compounds, particularly for the investigation of the extent to which polymerization residues are observable in situ in the material pores and for the assessment of the chemical integrity and recycling conditions of the grafted catalyst. From polymerization experiments with CL, initiated by n‐propanol and with [PH](1−t)[P(CH2)nSnBuCl2]t of various compositions as the supported catalyst, it appears that a partial 'burst' of the polystyrene support occurs when the length of the alkyl spacer is limited to n=6, as a result of polymer chains growing within the pores of the support. However, extension of the length of the aliphatic polymethylene spacer from 6 to 11 carbon atoms preserves the support integrity and allows the production of catalyst‐deprived poly(ε‐caprolactone) (PCL) oligomers. A preliminary attempt to recycle the heterogeneous catalyst has shown that very good reproducibility can be obtained, in terms of both catalyst activity and molecular‐weight parameters of the as‐recovered PCL polyester chains.
Sensing Nitrite through a Pseudoazurin–Nitrite Reductase Electron Transfer Relay
Authors: Astier Yann , Canters Gerard W. , Davis Jason J. , Hill H. Allen O. , Verbeet Martin P. , Wijma Hein J. 
Published: May 2005

AbstractNitrite is converted to nitric oxide by haem or copper‐containing enzymes in denitrifying bacteria during the process of denitrification. In designing an efficient biosensor, this enzymic turnover must be quantitatively assessed. The enzyme nitrite reductase from Alcaligenes faecalis contains a redox‐active blue copper centre and a nonblue enzyme‐active copper centre. It can be covalently tethered to modified gold‐electrode surfaces in configurations in which direct electron transfer is possible. A surface cysteine mutant of the enzyme can be similarly immobilised on bare electroactive gold substrates. Under such circumstances, however, electron transfer cannot be effectively coupled with substrate catalytic turnover. In using either the natural redox partner, pseudoazurin, or ruthenium hexammine as an “electron‐shuttle” or “conduit” between enzyme and a peptide‐modified electrode surface, the coupling of electron transfer to catalysis can be utilised in the development of an amperometric nitrite sensor.
Cross‐Linking of Polyolefins: A Study by Thermoporosimetry with Benzene Derivatives as Swelling Solvents
Authors: Billamboz Nicolas , Nedelec Jean‐Marie , Grivet Manuel , Baba Mohamed 
Published: May 2005

AbstractThe solvents o‐, m‐, p‐xylene, p‐dichlorobenzene, 1,2,4‐trichlorobenzene, and naphthalene were calibrated as condensates used in the thermoporosimetry technique. Exponential relationships were found connecting the pore radii Rp (in nm) and the freezing‐point depression of the swelling solvent ΔT (in °C) on the one hand and the apparent energy of crystallization Wa (in J cm−3) and ΔT on the other hand: ${{\rm R}{_{p}}={\rm t}\,exp[- 1/({\rm c}{\Delta}{\rm T})]}$; ${{\rm W}{_{a}}={\rm W}{_{0}}\,exp({\Delta}{\rm T}/{\rm f})}$. Pore‐ or mesh‐size distributions can be derived from differential scanning calorimetry results by using the following equation: ${d{\rm V}{_{p}}/d{\rm R}{_{p}}={\rm k}\{[{\rm cY}({\rm T}){\Delta}{\rm T}{^{2}}]/[{\rm W}{_{a}}{\rm R}{_{p}}]\}}$. All the numerical parameters were determined. Polyethylene and polypropylene samples, cross‐linked with high‐energy electrons or γ‐rays, were submitted to thermoporosimetry study. Relative mesh‐size distributions, which depend on the polymer/solvent pair, were calculated for these polyolefins with o‐, m‐, and p‐xylene as solvent and were found to be in the same sequence as those of their degrees of swelling and the irradiation doses received.
A Theoretical Investigation of Substituent Effects on the Absorption and Emission Properties of a Series of Terpyridylplatinum(II) Acetylide Complexes
Authors: Liu Xiao‐Juan , Feng Ji‐Kang , Meng Jian , Pan Qing‐Jiang , Ren Ai‐Min , Zhou Xin , Zhang Hong‐Xing 
Published: May 2005

AbstractA comprehensive calculational investigation has been carried out on a series of complexes of the type [(terpyridyl‐R1)Pt(C≡C‐R2)], where terpyridyl‐R1 is a series of substituted 2,2':6',2''‐terpyridyl ligands and C≡C‐R2 is a series of substituted acetylide ligands. In one series of complexes (I), the energy of the electronic excited state is varied by changing the substituents on the terpyridyl ligand (R1). In a second series of complexes (II), this electronic structure variation is obtained by changing the para substituents (R2) of the acetylide ligand. The effect of varying the substituents on the lowest‐energy excited states of the complexes has been assessed by calculating their electronic structures and excitation energies. We anticipated that introduction of electron‐withdrawing substituents on the terpyridyl ligand will benefit the LLCT (or MLCT) and prohibit the nonradiative pathways via d‐d transitions in these complexes; introduction of electron‐donating substituents on the acetylide ligand can also prohibit the nonradiative pathways by increasing the energy gaps between the HOMO–LUMO and d‐d transitions. The results also reveal that the lowest‐energy excitations of all complexes of series I and IIa–b complexes are dominated by a π(C≡C) → π*(terp) (LLCT) transition mixed with some energetically dπ(Pt) → terpyridyl (MLCT) transition. However, for the complexes IIc–IId, in which phenyl rings are introduced on the acetylide ligand, the lowest‐lying absorptions of IIc and IId are predominately LLCT in character, with less MLCT mixture, due to a lower contribution of the Pt(d) orbital to the HOMO, while for IIe, with a stronger donor on the acetylide, the lowest‐lying absorption is completely LLCT in character. The absorption and emission calculations using the TDDFT method are based on the optimized geometries obtained at the B3LYP/LanL2DZ and CIS/LanL2DZ levels, respectively. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
Synthesis and Reactions of Mixed N,P Ligands
Authors: Bowen Richard J. , Fernandes Manuel A. , Gitari Patricia W. , Layh Marcus , Moutloali Richard M. 
Published: May 2005

AbstractThe gold complexes [RN=C(R')CH(R)PPh2(AuCl)] (6a, R' = tBu; 6b, R' = Ad; R = SiMe3) were synthesised from the ketimines RN=C(R')CH(R)PPh2 (2a, R' = tBu; 2b, R' = Ad; R = SiMe3) and Me2SAuCl. The hydrolysis of the complexes to [H2NC(R')=CHPPh2(AuCl)] (8a, R' = tBu; 8b, R' = Ad) in protic solvents was studied and the reaction intermediate [H(R)NC(tBu)=CHPPh2(AuCl)] (7a) was isolated. The ketimines were further reacted with PhPCl2 to the cyclic phosphonium salts [Ph2PP(Ph)N(H)C(R')=CH]X (3a, R' = tBu, X = Cl; 3c, R' = Ad, X = Cl; 3d, R' = Ad, X = BPh4) and in the case of 3a oxidised with sulfur to give the ring‐opened β‐keto thiophosphane oxide Ph2P(S)CH2C(O)tBu (9). All compounds were fully characterised by NMR spectroscopy and in the case of 6b, 8a and 9 by X‐ray crystallography. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
The Role of C–H···O Interactions in the Solid and Liquid‐Phase Structures of Methyltrioxo Rhenium
Authors: Vaz Pedro D. , Ribeiro‐Claro Paulo J. A. 
Published: May 2005

AbstractThe importance of C–H···O hydrogen bonds involving the less common Re=O acceptor group in the small organometallic methyltrioxorhenium (MTO) is studied by combined vibrational spectroscopy and ab initio calculations. The observed vibrational spectrum is well described by the calculated spectrum of a C–H···O bonded dimer, which accounts for the symmetry decrease and the intermolecular interactions in the solid. Spectral evidence indicates both C–H···O and O–H···O hydrogen bonds are formed in the MTO/methanol solutions. The Re=O stretching mode is sensitive to hydrogen bonding, but the major effects of intermolecular association are observed in the βC–H and νC–H modes of MTO. Ab initio calculations for the MTO/methanol system predict the coexistence of both the Lewis adduct and the hydrogen‐bonded complex, with an energy difference of ca. 1.2 kJ·mol–1. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
The Structural Chemistry of N‐Monolithium Borazines
Authors: Nöth Heinrich , Rojas‐Lima Susana , Troll Alexander 
Published: May 2005

AbstractTrimethylborazine (Me3B3N3H3, 1) reacts with RLi (R = nBu, tBu) in hexane solution by alkyl group exchange to give a mixture of borazines Me3–nRnB3N3H3. In contrast, deprotonation of 1 to Me3B3N3H2Li (2) occurs upon treatment with MeLi in diethyl ether solution or RLi (R = nBu, tBu) complexed with tetramethylethylenediamine (TMEDA), pentamethyldiethylentriamine (PMDTA), or trimethylhexahydrotriazine (TMTA) in hexane solution, to give solvates of 2. [(Me3B3N3H2)Li(OEt2)] (2a), [(Me3B3N3H2)Li(tmta)] (2c), and [(Me3B3N3H2Li)4(tmeda)3] (2b) contain dimeric units of 2. In the case of 2b two of these dimers are bridged by one tmeda molecule, while the other two are coordinated to a lithium atom of one of its dimeric units, respectively. This molecule therefore contains tri‐ and tetracoordinated Li atoms. In contrast, [(Me3B3N3H2)Li(pmdta)] (2c) is monomeric. The N‐lithiation leads to a distortion of the planar B3N3 ring system: the B–N bonds at the metallated N atoms are short, the next opposite B–N pair is the longest, followed by a shorter B–N bond involving the B atom in the para position. However, all B–N bonds are longer than in the parent compound 1. Reaction of tBu3B3N3H3 (3) with tBuLi in the presence of triisopropylhexahydrotriazine (TIPTA) in hexane leads to the salt [(tipta)2Li][tBu4B3N3H3] (4), while deprotonation occurs with tBuLi(tmta) to give monomeric [(tBu3B3N3H2)Li(tmta)] (5) after refluxing the reaction mixture. Similarly, (Me2N)3B3N3H3 (6) can be deprotonated with RLi in the presence of TMTA to give monomeric [{(Me2N)3B3N3H2}Li(tmta)] (7b). The N‐lithiation has almost no influence on the shielding of the boron nucleus of the borazine nuecleus. Attempts to obtain di‐ and trilithiated 1 as pure compounds failed: alkyl group exchange and borate formation as well as destruction of the borazine ring were detected by NMR spectroscopy. However, treatment of these reaction mixtures with MeBr gave Me3B3N3NH3–nMen (n = 0–3). (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
Supramolecular Copper Phenanthroline Racks: Structures, Mechanistic Insight and Dynamic Nature
Authors: Kalsani Venkateshwarlu , Bodenstedt Heinrich , Fenske Dieter , Schmittel Michael 
Published: May 2005

AbstractHerein, we describe the preparation of several dynamic multicomponent supramolecular racks based on copper phenanthroline complexes using the HETPHEN concept (heteroleptic bisphenanthroline complexes). This approach employs bulky aryl substituents at the bisimine coordination sites to control the coordination equilibrium. The racks were characterised by spectroscopic methods, both in solution (1H NMR, ESI‐MS, UV/Vis, vapour pressure osmometry) and in the solid state (X‐ray). Ligand exchange studies established the reversible nature of the aggregates, the details of which are vital for the development of higher level multicomponent structures. In this regard, the present rack assemblies contrast to the large multitude of known rack motifs that are almost exclusively built using kinetically inert coordination building blocks. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)