bluuebunny/crossref_metadata_2025_split huggingface dataset:
The effect of Echis carinatus crude venom and purified protein fractions on carbohydrate metabolism in rats
Authors: Al‐Saleh Saad S. M. 
Published: January 2005

AbstractEchis carinatus crude venom was fractionated into 11 protein fractions by preparative native polyacrylamide gel electrophoresis (PAGE). All fractions except fractions 5 and 10 appeared as a single band on analytical native PAGE. Purified venom fractions 1, 4, 8, 10 and 11 appeared as single bands on SDS‐PAGE whereas fractions 2, 3 and 7 contained two bands and fraction 6 contained three bands. Fractions 1 and 3 exhibited basic pI (7.3 and 7.6) respectively, while fractions 2, 4, 6, 8, 10 and 11 showed an acidic pI. Amino acid analysis also showed that crude venom is rich in acidic amino acids. A significant hyperglycaemia was produced by i.p. injection of E. carinatus crude venom, after 15 min of envenomation which persisted even after 24 h. Along with hyperglycaemia there was a significant decrease of liver glycogen at 15 min and 1, 12 and 24 h. A significant decrease of plasma [pyr + lac] levels was found from 15 min to 24 h. The liver [pyr + lac] levels increased significantly after 24 h. Skeletal muscle [pyr + lac] level was significantly decreased after 24 h of envenomation. Fractions 2 and 6 produced the highest increase in plasma glucose after 12 h and fraction 7 after 24 h. The plasma insulin level was significantly decreased by these three fractions (2, 6 and 7). So it can be hypothesized that the hyperglycaemia may result from a direct effect of a venom component on plasma insulin. Fractions 7, 8 and 11 caused the highest decrease in plasma [pyr + lac] while fractions 1, 2, 3, 4 and 8 produced the most significant decrease in liver [pyr + lac]. The most significant increase in lactate dehydrogenase level was also produced by fractions 1, 2, 3, 4 and 8. Copyright © 2001 John Wiley & Sons, Ltd.
Cross‐reactivity of some antibodies to human epitopes with shrimp Pandalus borealis proteins: a possible aid in validation and characterization of crustacean cells in vitro
Authors: Lyons‐Alcantara Maria , Lambkin Helen A. , Nordmo Rolf , Lyng Fiona , Mothersill Carmel 
Published: January 2005

AbstractCell characterization of primary cultures in vertebrates is well established but not in marine invertebrates. This fact is hampering advances in the development of tissue cultures from this species. In the present study, a panel of antibodies to structural proteins, stress proteins, oncogenes and proliferation antigens, developed against mammalian antigens, were tested in paraffin sections of the crustacean Pandalus borealis tissues. Several tissues were analysed: hepatopancreas, gills, ovaries, epithelium under the cuticle and abdominal muscle. Specific antibodies to crustacean proteins are not commercially available. The immunocytochemical results show that antibodies to human epitopes cross‐react with antigens in the crustacean Pandalus borealis indicating that some cellular proteins are highly conserved in evolution. Cytokeratin, proliferating cell nuclear antigen, ras and p‐glycoprotein were detected by immunocytochemistry in Pandalus borealis. No immunoreactivity for Ki‐67 and metallothionein was observed. This system can help in validation and characterization of invertebrate cultures. Copyright © 2002 John Wiley & Sons, Ltd.
Evidence that glutamine is involved in neutrophil function
Authors: Pithon‐Curi Tania C. , Trezena Ariane G. , Tavares‐Lima Wothan , Curi Rui 
Published: January 2005

AbstractPhosphate‐dependent glutaminase (PDG) activity, a key enzyme of glutamine metabolism, was determined in neutrophils obtained from the intra‐peritoneal cavity (PC) or bronchoalveolar space (BAS) after administration of 1 ml or 100 μl, respectively of saline, glycogen solution (1%) or lipopolysaccharide (LPS 0.1 mg (100 μl)−1). Neutrophils were obtained by lavage of both sites with 20 ml saline 24 h after the administration of the stimuli. Glycogen and LPS, depending on the site the cells were obtained from, differently modulated PDG activity. Cells from BAS stimulated by glycogen or LPS had raised PDG activity to 30.5 ± 5.2 and 42.7 ± 12.1 nmol min−1 mg−1 protein, respectively, when compared with saline (9.1 ± 0.9 nmol min−1 mg−1 protein); mean ± SEM. On the other hand, cells from PC showed different PDG activity: 52.0 ± 12.6 nmol min−1 mg−1 for saline, 36.5 ± 9.5 nmol min−1 mg−1 for glycogen, and 76.6 ± 11.2 nmol min−1 mg−1 for LPS; mean ± SEM. Therefore, PDG activity varies with the site from which neutrophils are obtained and the stimulus imposed. The effect of glutamine on nitric oxide (NO) and tumour necrosis factor (TNF) production by peritoneal neutrophils, obtained after glycogen administration, cultured in the presence of LPS (0.5 μg ml−1) was also examined. The addition of glutamine at concentrations varying from 2 to 20 mM did not markedly affect NO production. Glutamine alone at 2 mM did not modify the production of TNF but in the presence of LPS caused a significant decrease. So, glutamine may preserve the function of neutrophils during infections and injuries. Copyright © 2001 John Wiley & Sons, Ltd.
Separation and purification of Echis coloratus venom and some biological and biochemical effects of the proteins
Authors: Al‐Saleh S.S. , Ghneim H.K. , Haddad H.Y. , Khan S.U. 
Published: January 2005

AbstractCrude venom of Echis coloratus was separated into seven protein fractions using 7% preparative native polyacrylamide gel electrophoresis. The effect of crude venom and seven venom protein fractions (F1–F7) from Echis coloratus on key metabolic activities of fibroblast cultures was investigated. Confluent cultures were incubated with the venom proteins for 3 h at 37°C. The specific activity of phosphofructokinase, was significantly lowered upon incubation with the crude venom and with fractions 2, 3, 4 and 6. Citrate synthase activity was significantly lowered by the crude venom and by fractions 2 and 3. Glycogen phosphorylase activity was significantly increased by the crude venom and by fractions 2, 3, 4 and 6 leading to a significant concurrent drop in glycogen content. Creatine kinase activity was significantly increased by the crude venom and by fractions 3, 4, 5 and 6. Cellular ATP levels rose significantly upon incubation with the crude venom and with fractions 3, 4, 5 and 6. Incubation of cell sonicates with all the venom proteins did not significantly alter the activity or content of any of the studied parameters. Copyright © 2002 John Wiley & Sons, Ltd.
Generalized PLS regression
Authors: Xu Qing‐Song , Liang Yi‐Zeng , Shen Hai‐Lin 
Published: January 2005

AbstractThe present paper develops a class of generalized partial least squares (GPLS) regression methods. GPLS can be regarded as a kind of weighted partial least squares regression method. Two special cases of them, ridge partial least squares (RPLS) and generalized ridge partial least squares (GRPLS) regression methods, are discussed in detail. RPLS and GRPLS combine partial least squares (PLS) with ridge regression (RR) and generalized ridge regression (GRR) respectively. It is shown that the estimated coefficient vectors by RPLS and GRPLS are shrunken PLS estimators and their prediction power is not so sensitive to the components included in the model compared to PLS. The four methods RR, PLS, RPLS and GRPLS are compared on the basis of three data sets under the criteria of prediction residual error sum of squares (PRESS) and mean squared error of prediction (MSEP). Copyright © 2001 John Wiley & Sons, Ltd.
Pseudo alternating least squares algorithm for trilinear decomposition
Authors: Chen Zeng‐Ping , Li Yang , Yu Ru‐Qin 
Published: January 2005

AbstractIn chemistry, PARAFAC is one of the most widely used algorithms for trilinear decomposition. However, the problem of PARAFAC requiring an accurate estimation of the number of factors in the system under study limits its applications to some extent. This troublesome problem has been tackled by the pseudo alternating least squares (PALS) algorithm designed in this paper. PALS is a unique algorithm which tries to alternately optimize three different objective functions to obtain the solutions for the trilinear decomposition model. It has the outstanding feature of being resistant to the influence of N (the number of factors chosen in calculation), which has been proved mathematically under some mild conditions. Although the optimization procedure of PALS is different from that of PARAFAC, an alternating least squares scheme, and hinders a straightforward analysis of its convergence properties, studies on simulated as well as real data arrays reveal that PALS can often converge to satisfactory results within a reasonable computation time, even if excess factors are used in calculation. Copyright © 2001 John Wiley & Sons, Ltd.
Investigation on quantitative relationship between chemical shift of carbon‐13 nuclear magnetic resonance spectra and molecular topological structure based on a novel atomic distance–edge vector (ADEV)
Authors: Liu Shushen , Liu Hailing , Yu Banmei , Cao Chenzhong , Li Shengshi Zhiliang 
Published: January 2005

AbstractA set of novel graph theoretical parameters, called the atomic distance–edge vector (ADEV), was developed in our laboratories. A regression equation linking the carbon‐13 chemical shift (CS) to an ADEV containing 16 descriptor variables of various chemically non‐equivalent carbon atoms in a molecule was obtained using multiple linear regression (MLR). The regression model was used to predict the carbon‐13 nuclear magnetic resonance (13C NMR) spectra of unknown alkanes. It was found that the estimated CS values were in good agreement with the experimental CS values. Copyright © 2001 John Wiley & Sons, Ltd.
Selecting significant factors by the noise addition method in principal component analysis
Authors: Dable Brian K. , Booksh Karl S. 
Published: January 2005

AbstractThe noise addition method (NAM) is presented as a tool for determining the number of significant factors in a data set. The NAM is compared to residual standard deviation (RSD), the factor indicator function (IND), chi‐squared (χ2) and cross‐validation (CV) for establishing the number of significant factors in three data sets. The comparison and validation of the NAM are performed through Monte Carlo simulations with noise distributions of varying standard deviation, HPLC/UV‐vis chromatographs of a mixture of aromatic hydrocarbons, and FIA of methyl orange. The NAM succeeds in correctly identifying the proper number of significant factors 98% of the time with the simulated data, 99% in the HPLC data sets and 98% with the FIA data. RSD and χ2 fail to choose the proper number of factors in all three data sets. IND identifies the correct number of factors in the simulated data sets but fails with the HPLC and FIA data sets. Both CV methods fail in the HPLC and FIA data sets. CV also fails for the simulated data sets, while the modified CV correctly chooses the proper number of factors an average of 80% of the time. Copyright © 2001 John Wiley & Sons, Ltd.
Genetic algorithms in chemometrics and chemistry: a review
Authors: Leardi Riccardo 
Published: January 2005

AbstractThe use of genetic algorithms has been growing exponentially since Holland published the first papers about them. Thanks to the extraordinary increase in calculation power, nowadays it is possible to apply them to extremely complex problems. A considerable number of papers in which genetic algorithms have been applied have been published in several scientifical journals. This review is of course far from being a complete summary of the application of genetic algorithms to chemical problems; its goal is to show the reader the main fields of application of this technique, together with providing a list of references on the subject. Copyright © 2001 John Wiley & Sons, Ltd.
The GOLPE procedure for predicting olive crop production from climatic parameters
Authors: Clementi Monica , Clementi Sergio , Fornaciari Marco , Orlandi Fabio , Romano Bruno 
Published: January 2005

AbstractThis paper reviews the philosophy of the GOLPE procedure, explaining the reasons for the validation criterion and variable selection method used and comparing GOLPE with other regression and variable selection methods. Its application to olive production, for a training set of 16 years, allows one to improve the uncertainty of prediction of the yearly crop production from temperature, rain, heliophany, humidity and wind from 30% to 14% and to indicate the climatic parameters affecting crop production. Copyright © 2001 John Wiley & Sons, Ltd.
Strategies for subset selection of parts of an in‐house chemical library
Authors: Andersson Per M. , Sjöström Michael , Wold Svante , Lundstedt Torbjörn 
Published: January 2005

AbstractWhen a company decides to perform biological testing of their ‘in‐house’ library, i.e. compounds which have been synthesized or purchased over the years, it is usually not feasible or desirable to test all of them using e.g. high‐throughput screening (HTS). The limitation is the usually high number of compounds to test (104–106) leading to practical limitations and high costs in terms of both material costs and disposal considerations. Therefore it is often desirable to make a selection of which compounds to include in the biological testing. A challenge is how to make this selection in order to cover the structural space of the in‐house library as well as possible. Here we present and discuss different selection strategies based mainly on statistical molecular design (SMD). These methods require different prior information about the compounds under investigation, e.g. characterization of the chemical structure, affinity/biological activity data or neither of these. Which method to be used is largely problem‐dependent, i.e. the composition and origin of the library, and hence the structural space, are of great importance. Chemical and biological knowledge about the system under investigation should as far as possible be considered when making the final decision on which method to apply. Copyright © 2001 John Wiley & Sons, Ltd.
Sufficient conditions for unique solutions within a certain class of curve resolution models
Authors: Smilde Age K. , Hoefsloot Huub C. J. , Kiers Henk A. L. , Bijlsma Sabina , Boelens Hans F. M. 
Published: January 2005

AbstractCurve resolution is a class of techniques concerned with estimating profiles underlying a set of measurements of time‐evolving chemical systems. In general, the estimated profiles are not unique. Both intensity and rotational ambiguities exist in the solutions of these problems. Constraints can be imposed on the solution to decrease the ambiguity. Some chemical systems show closure. It is proven that imposing a closure constraint is sufficient to solve the intensity ambiguity but not the rotational ambiguity. Some curve resolution techniques are concerned with estimating reaction rate or equilibrium constants from measurements of evolving systems. Then a kinetic model is imposed on the measured data. It is proven that imposing a certain class of kinetic models is sufficient to solve both the rotational and the intensity ambiguity. Copyright © 2001 John Wiley & Sons, Ltd.
Singlet Exciplexes between a Thioxanthone Derivative and Substituted Aromatic Quenchers: Role of the Resonance Integral
Authors: Dossot Manuel , Allonas Xavier , Jacques Patrice 
Published: January 2005

AbstractFluorescence quenching of a thioxanthone derivative by methyl‐ and methoxy‐substituted benzenes (MeB and MeOB, respectively) is performed in solvents of different polarity. Emissive exciplexes are observed even in polar solvents and provide kinetic and spectroscopic data over a large scale of solvent polarity. These data were subsequently analyzed by use of a new theoretical model that leads to a thermodynamic relationship between exciplex and electron‐transfer driving forces ΔGexcand ΔGet, respectively. The remarkable agreement found between this model and both kinetic and spectroscopic data supports its validity. Moreover, the difference observed between MeB and MeOB compounds in quenching efficiency is analyzed by this model and provides the main parameters governing exciplex features, especially the resonance integral between locally excited and charge‐transfer states.
Electronic, Vibrational, and Structural Properties of a Spin‐Crossover Catecholato–Iron System in the Solid State: Theoretical Study of the Electronic Nature of the Doublet and Sextet States
Authors: Simaan A. Jalila , Boillot Marie‐Laure , Carrasco Rosa , Cano Joan , Girerd Jean‐Jacques , Mattioli Tony A. , Ensling Jürgen , Spiering Hartmut , Gütlich Philipp 
Published: January 2005

AbstractAs a functional model of the catechol dioxygenases, [(TPA)Fe(Cat)]BPh4 (TPA = tris(2‐pyridylmethyl)amine and Cat = catecholate dianion) exhibits the purple‐blue coloration indicative of some charge transfer within the ground state. In contrast to a number of high‐spin bioinspired systems, it was previously shown that, in the solid state, [(TPA)Fe(Cat)]BPh4 undergoes a two‐step S = 1/2⇄S = 5/2 spin‐crossover. Therefore, the electronic and vibrational characteristics of this compound were investigated in the solid state by UV/Vis absorption and resonance Raman spectroscopies over the temperature range of the transition. This allowed the charge‐transfer transitions of the low‐spin (LS) form to be identified. In addition, the vibrational progression observed in the NIR absorption of the LS form was assigned to a five‐membered chelate ring mode. The X‐ray crystal structure solved at two different temperatures, shows the presence of highly distorted pseudo‐octahedral ferric complexes that occupy two nonequivalent crystalline sites. The variation of the molecular parameters as a function of temperature strongly suggests that the two‐step transition proceeds by a successive transition of the species in the two nonequivalent sites. The thermal dependence of the high‐spin fraction of metal ions determined by Mössbauer experiments is consistent with the magnetic data, except for slight deviations in the high temperature range. The optimized geometries, the electronic transitions, vibrational frequencies, and thermodynamic functions were calculated with the B3LYP density functional method for the doublet and the sextet states. The finding of a ground state that possesses a significant mixture of FeIII–catecholate and FeII–semiquinonate configurations is discussed with regard to the set of experimental and theoretical data.
A Nonanuclear Copper(II) Polyoxometalate Assembled Around a μ‐1,1,1,3,3,3‐Azido Ligand and Its Parent Tetranuclear Complex
Authors: Mialane Pierre , Dolbecq Anne , Marrot Jérôme , Rivière Eric , Sécheresse Francis 
Published: January 2005

AbstractReaction of CuII, [γ‐SiW10O36]8−, and N3− affords three azido polyoxotungstate complexes. Two of them have been characterized by single‐crystal X‐ray diffraction. Complex KNaCs10[{γ‐SiW10O36Cu2(H2O)(N3)2}2]⋅26 H2O (1) is obtained as crystals in few hours after addition of CsCl. This linear tetranuclear CuII complex consists in two [γ‐SiW10O36Cu2(H2O)(N3)2]6− units connected through two WO bridges. When the filtrate is left to stand for one night, a new complex is obtained. From both elemental analysis and IR spectroscopy, it has been postulated that this compound could be formulated K1.5Cs5.5[SiW10O37Cu2(H2O)2(N3)]⋅14 H2O (1 a), showing the loss of one azido ligand per polyoxometalate unit. Finally, when no cesium salt is added to the reaction medium, the nonanuclear complex K12Na7[{SiW8O31Cu3(OH)(H2O)2(N3)}3(N3)]⋅24 H2O (2) is obtained after three days. Compound 2 crystallizes in the R3c space group and consists in three {Cu3} units related by a C3 axis passing through the exceptional μ‐1,1,1,3,3,3‐azido bridging ligand. Each trinuclear CuII unit is embedded in the [γ‐SiW8O31]10− ligand, an unprecedented tetravacant polyoxometalate, showing that partial decomposition of the [γ‐SiW10O36]8− precursor occurs with time in such experimental conditions. Magnetically, complex 1 behaves as two isolated {Cu2(μ1,1‐N3)2} pairs in which the metal centers are strongly ferromagnetically coupled (J=+224 cm−1, g=2.20), the coupling through the WO bridges being negligible. The magnetic behavior of complex 2 has also been studied. Relatively weak ferromagnetic couplings (J1=+1.0 cm−1, J2= +20.0 cm−1, g=2.17) have been found inside the {Cu3} units, while the intertrimeric magnetic interactions occurring through the hexadentate azido ligand have been found to be antiferromagnetic (J3=−5.4 cm−1) and ferromagnetic (J4=+1.3 cm−1) with respect to the end‐to‐end and end‐on azido‐bridged CuII pairs, respectively.
Why Does Pivalaldehyde (Trimethylacetaldehyde) Unexpectedly Seem More Basic Than 1‐Adamantanecarbaldehyde in the Gas Phase? FT‐ICR and High‐Level Ab Initio Studies
Authors: Quintanilla Esther , Dávalos Juan Z. , Abboud José‐Luis M. , Alcamí Manuel , Cabildo M. Pilar , Claramunt Rosa M. , Elguero José , Mó Otilia , Yáñez Manuel 
Published: January 2005

AbstractFourier transform ion cyclotron resonance spectroscopy (FT ICR) techniques, including collision‐induced dissociation (CID) methodology, were applied to the study of the gas‐phase protonation of pivalaldehyde (1) and 1‐adamantanecarbaldehyde (2). A new synthetic method for 2 was developed. The experiments, together with a thorough computational study involving ab initio and density functional theory (DFT) calculations of high level, conclusively show that upon monoprotonation in the gas phase, compound 1 yields monoprotonated methyl isopropyl ketone 3. The mechanism of this gas‐phase acid‐catalyzed isomerization is different from that reported by Olah and Suryah Prakash for the reaction in solution. In the latter case, isomerization takes place through the diprotonation of 1.
Primary and Secondary Phosphane Complexes of Metalloporphyrins: Isolation, Spectroscopy, and X‐ray Crystal Structures of Ruthenium and Osmium Porphyrins Binding Phenyl‐ or Diphenylphosphane
Authors: Xie Jin , Huang Jie‐Sheng , Zhu Nianyong , Zhou Zhong‐Yuan , Che Chi‐Ming 
Published: January 2005

Abstract[RuII(por)(PHnPh3−n)2], [OsII(por)(CO)(PHnPh3−n)] (n=1, 2), and [OsII(F20‐tpp){P(OH)Ph2}(PHPh2)] (F20‐tpp=5,10,15,20‐tetrakis(pentafluorophenyl)porphyrinato dianion) were prepared from the reaction of [MII(por)(CO)] (M=Ru, Os) or [OsVI(por)O2] with the respective primary/secondary phosphane and characterized by 1H NMR, 31P NMR, UV/Vis, and IR spectroscopy, mass spectrometry, and elemental analysis. The reaction of [OsVI(por)O2] with PHPh2 also gave minor amounts of [OsII(por){P(OH)Ph2}2]. [RuII(F20‐tpp)(PH2Ph)2] exhibits a remarkable stability toward air and shows a reversible metal‐centered oxidation couple at E1/2=0.39 V versus [Cp2Fe]+/0 in the cyclic voltammogram. The structures of [RuII(F20‐tpp)(PH2Ph)2]⋅2CH2Cl2, [RuII(4‐Cl‐tpp)(PHPh2)2]⋅2 CH2Cl2 (4‐Cl‐tpp=5,10,15,20‐tetrakis(p‐chlorophenyl)porphyrinato dianion), [RuII(F20‐tpp)(PHPh2)2], and [OsII(F20‐tpp){P(OH)Ph2}2] were determined by X‐ray crystallography and feature RuP distances of 2.3397(11)–2.3609(9) Å and an OsP distance of 2.369(2) Å.
Ellipticity: A Convenient Tool To Characterize Electrocyclic Reactions
Authors: López Carlos Silva , Faza Olalla Nieto , Cossío Fernando P. , York Darrin M. , de Lera Angel R. 
Published: January 2005

AbstractThe ellipticity of the electron density is proposed as a convenient tool to characterize electrocyclic reactions. The study of the electron density offers several advantages since it is an experimental observable. This simple topological index has proven powerful and robust for the characterization of a wide variety of electrocyclic and pseudoelectrocyclic processes. This property is sensitive to changes in the anisotropy of the electron density in the bond‐forming region and provides an insightful description of the events occurring along the reaction coordinate.