bluuebunny/crossref_metadata_2025_split huggingface dataset:
Reversed phase liquid chromatography trace analysis of pesticides in soil by on‐column sample pumping large volume injection and UV detection
Authors: Hutta Milan , Chalányová Mária , Halko Radoslav , Góra Róbert , Dokupilová Svetlana , Rybár Ivan 
Published: June 2009

AbstractThe idea of utilization of one hydraulic line of a common commercial HPLC pump for direct on‐column sample pumping injection of large sample volumes, 20 mL, was further investigated with the aim to develop multicomponent pesticides trace residues HPLC method in gram soil samples. Target pesticides group involve asulam, atrazine, 2,4‐D, PCA, propazine, simazine, 4‐chloro‐2‐methylphenoxyacetic acid, 2‐(4‐chloro‐2‐tolyloxy) propionic acid, chlortoluron, metoxuron, epoxiconazole. The results proved the applicability of this approach in experiments with mixtures of analytes at low ng/mL levels. Analysis of 20 mL of soil leachates and extracts of fortified soil samples containing these pesticides at the 10–50 ng/g level (in dry soil) revealed good figures of merit, also in the presence of large excess of humics. LODs achieved by detection at 220 nm evaluated from calibration runs of spiked soil extracts by Hubaux et al. method ranged from 5–12 ng per injected volume. For 20 mL large volume injection it represents 0.25–0.6 ng/mL of diluted soil extract, or 2.5–6 ng/mL of crude extract, or 6–5 ng/g dry soil. Recoveries of pesticides at concentration levels approaching half of maximum allowable concentration of pesticides in soil (100 ng/g) ranged from 85 to 98% with acceptable reproducibility, except asulam and metoxuron.
Side‐chain modified bile acids: chromatographic separation of 23‐methyl epimers
Authors: Natalini Benedetto , Sardella Roccaldo , Gioiello Antimo , Carbone Giovanni , Dawgul Malgorzata , Pellicciari Roberto 
Published: June 2009

AbstractOwing to the re‐flourished interest towards the bile acids (BAs) as versatile signalling hormones endowed with diverse endocrine functions, the development of reliable analytical protocols monitoring the synthesis of new BA‐based receptor modulators, still represents a cogent concern. On this basis, for the first time, a HPLC study has been engaged with the aim to set up suitable chromatographic conditions for the analysis of three different epimeric couples of 23‐methyl‐substituted unconjugated BAs. Three different methods (one for each couple) have been successfully established and then validated. Good precision and accuracy (evaluated both in the short and long period) as well as appreciably low LOD and LOQ values have turned out. Moreover, the engagement of an evaporative light scattering detector (ELSD) has proven its high effectiveness for the analysis of such steroidal species.
The lipophilicity indices of flavonoids estimated by reversed‐phase liquid chromatography using different computation methods
Authors: Briciu Rodica Domnica , Kot‐Wasik Agata , Namiesnik Jacek , Sârbu Costel 
Published: June 2009

AbstractThe chromatographic behavior of some flavonoids was established by RP‐HPLC on RP‐18 (LiChroCART, LiChrosphere RP‐18e), RP‐8 (Zorbax, Eclipse XDB‐C8), CN (Säulentechnik, LiChrosphere CN100) columns. The mobile phases were mixtures of methanol‐water in different volume proportions from 70 to 80% v/v for RP‐18 and RP‐8, while for the CN column the proportions were between 66 and 70% v/v. The lipophilicity was expressed through different lipophilicity descriptors such as mean of k (mk), mean of log k (mlog k), log kW, S, f0, and scores of k and log k corresponding to the first principal component. The experimental lipophilicity indices are directly correlated with the computed values, via computer software and internet module, at a high analytical level. Furthermore, the results obtained applying principal component analysis to k and/or log k values allow the prediction and explanation of the interaction involved in the retention mechanism which takes place between the compounds and the employed stationary phases during the development.
Determination of nonylphenol and nonylphenol ethoxylates in wastewater using MEKC
Authors: Núñez Laura , Wiedmer Susanne K. , Parshintsev Jevgeni , Hartonen Kari , Riekkola Marja‐Liisa , Tadeo José L. , Turiel Esther 
Published: June 2009

AbstractNonylphenol ethoxylates (NPEOx) are surfactants which are used worldwide and can be transformed in the environment by microorganisms to form nonylphenol (NP). Analysis of these compounds was carried out with micellar electrokinetic capillary chromatography (MEKC). Different parameters such as background electrolyte (BGE) solution, pH, type of surfactant, and sample stacking were optimized. The use of CHES (20 mM, pH 9.1) in combination with 50 mM sodium cholate as a surfactant as BGE solution, together with sample stacking using 50 mM NaCl in the sample and an injection time of 20 s, provided the best separation of the compounds studied. The method was applied to the determination of target analytes in two types of sludge water coming from two steps of a wastewater treatment plant. Liquid–liquid extraction was carried out using toluene as solvent, resulting in recoveries around 100% for all studied analytes. The presence of NPEOx was observed in the first step of the sludge water treatment, based on migration time and UV spectra. Identification was confirmed using tandem MS. LOQs of the studied compounds were in the range of 12.7 to 30.8 ng/mL, which is satisfactory for the analysis of real wastewater samples.
Kinetic study of the condensation of salicylaldehyde with diethyl malonate in a nonpolar solvent catalyzed by secondary amines
Authors: Bednarz Szczepan , Bogdal Dariusz 
Published: June 2009

AbstractThe kinetics of condensation between salicylaldehyde and diethylmalonate in a toluene solution in the presence of secondary amines (i.e., piperidine and 4‐piperidinopiperidine) as catalysts was investigated. It was found that the reaction proceeds via the Knoevenagel mechanism, and the kinetic model was numerically verified. © 2009 Wiley Periodicals, Inc. Int J Chem Kinet 41: 589–598, 2009
Evaluation of data for atmospheric models: Master Equation/RRKM calculations on the combination reaction ClO + NO2 → ClONO2, a recurring issue
Authors: Golden David M. 
Published: June 2009

AbstractExperimental data for the title reaction have been modeled using Master Equation/RRKM methods based on the Multiwell suite of programs. The starting point for the exercise was the empirical fitting provided by the NASA and IUPAC data evaluation panels, which represent the data in the experimental pressure ranges rather well. Despite the availability of quite reliable parameters for these calculations (molecular vibrational frequencies and a value of the bond dissociation energy of ClONO2, DH298(ClONO2) = 26.5 kcal mol−1, corresponding to ΔH00 = 25.35 kcal mol−1 at 0 K) and use of RRKM/Master Equation methods, fitting calculations to the reported data was anything but straightforward. Using these molecular parameters resulted in a discrepancy between the calculations and the database of rate constants of a factor of ca 4 at, or close to, the low‐pressure limit. © 2009 Wiley Periodicals, Inc. Int J Chem Kinet 41: 573–581, 2009
Abnormal salt effects on reactions between ions: The coupling of salt and solvent effects
Authors: Martin V. I. , Lopez‐Cornejo P. , Sanchez F. 
Published: June 2009

AbstractSalt effects on the reactions [Fe(CN)6]4− + S2O=8 and [Ru(NH3)5py]2+ + S2O have been studied in media of different dielectric constants constituted by mixtures of water with organic cosolvents. It is known that salt and solvent effects are coupled and, consequently, cannot be treated separately. This implies that salt (and solvent) effects need to be carefully analyzed before using them as a tool for mechanistic discrimination. © 2009 Wiley Periodicals, Inc. Int J Chem Kinet 41: 582–588, 2009
Fungal rhinosinusitis
Authors: Chakrabarti Arunaloke , Denning David W. , Ferguson Berrylin J. , Ponikau Jens , Buzina Walter , Kita Hirohito , Marple Bradley , Panda Naresh , Vlaminck Stephan , Kauffmann‐Lacroix Catherine , Das Ashim , Singh Paramjeet , Taj‐Aldeen Saad J. , Kantarcioglu A. Serda , Handa Kumud K. , Gupta Ashok , Thungabathra M. , Shivaprakash Mandya R. , Bal Amanjit , Fothergill Annette , Radotra Bishan D. 
Published: June 2009

AbstractBackground:Fungal (rhino‐) sinusitis encompasses a wide spectrum of immune and pathological responses, including invasive, chronic, granulomatous, and allergic disease. However, consensus on terminology, pathogenesis, and optimal management is lacking. The International Society for Human and Animal Mycology convened a working group to attempt consensus on terminology and disease classification.Discussion:Key conclusions reached were: rhinosinusitis is preferred to sinusitis; acute invasive fungal rhinosinusitis is preferred to fulminant, or necrotizing and should refer to disease of <4 weeks duration in immunocompromised patients; both chronic invasive rhinosinusitis and granulomatous rhinosinusitis were useful terms encompassing locally invasive disease over at least 3 months duration, with differing pathology and clinical settings; fungal ball of the sinus is preferred to either mycetoma or aspergilloma of the sinuses; localized fungal colonization of nasal or paranasal mucosa should be introduced to refer to localized infection visualized endoscopically; eosinophilic mucin is preferred to allergic mucin; and allergic fungal rhinosinusitis (AFRS), eosinophilic fungal rhinosinusitis, and eosinophilic mucin rhinosinusitis (EMRS) are imprecise and require better definition. In particular, to implicate fungi (as in AFRS and EMRS), hyphae must be visualized in eosinophilic mucin, but this is often not processed or examined carefully enough by histologists, reducing the universality of the disease classification. A schema for subclassifying these entities, including aspirin‐exacerbated rhinosinusitis, is proposed allowing an overlap in histopathological features, and with granulomatous, chronic invasive, and other forms of rhinosinusitis. Recommendations for future research avenues were also identified. Laryngosope, 2009
The assessment of pharyngocutaneous fistula rate in patients treated primarily with definitive radiotherapy followed by salvage surgery of the larynx and hypopharynx
Authors: Dirven Richard , Swinson Brian D. , Gao Kan , Clark Jonathan R. 
Published: June 2009

AbstractObjectives/Hypothesis:To determine whether definitive radiotherapy prior to surgery increases the rate of pharyngocutaneous fistula (PCF) following laryngectomy or hypopharyngectomy and to determine if differences in duration of time between definitive radiotherapy and surgery alters PCF rate.Study Design:A retrospective review of 152 patients treated surgically for primary laryngeal or hypopharyngeal squamous cell carcinoma.Methods:Following previous definitive radiotherapy treatment 38 patients underwent salvage surgery and 114 patients underwent primary surgery with curative intent. The PCF rate was assessed in both groups.Results:The rate of PCF was found to be significantly higher in the salvage surgery group than those undergoing primary surgery (34.2% vs. 15.7%) (P < .05). Fistula rate was also higher in the subgroup that received concurrent chemoradiation to radiotherapy alone (P = .002). The patients who developed PCF in the salvage surgery group had significantly lower median time to surgery (5.8 months) than the nonfistula group (9.8 months) (P = .032). PCF rate was 75% within 4 months of radiotherapy to salvage surgery compared to 25% after 4 months (P = .034). Within 12 months of radiotherapy this percentage was 48% compared to 0% after 12 months (P = .014). The median radiotherapy dose was significantly higher in those whose surgery was complicated by PCF (70 Gy) compared to patients who did not develop a fistula (64 Gy) (P = .001).Conclusions:Patients undergoing salvage surgery within 12 months, and in particular within 4 months, who have received high dose radiotherapy (>64 Gy) or concurrent chemoradiation are at high risk of developing PCF.
On extensions of some Flugede–Putnam type theorems involving (p, k)‐quasihyponormal, spectral, and dominant operators
Authors: Tanahashi Kotaro , Patel S. M. , Uchiyama Atsushi 
Published: June 2009

AbstractA Hilbert space operator S is called (p, k)‐quasihyponormal if S *k ((S *S)p – (SS *)p )Sk ≥ 0 for an integer k ≥ 1 and 0 < p ≤ 1. In the present note, we consider (p, k)‐quasihyponormal operator S ∈ B (H) such that SX = XT for some X ∈ B (K,H) and prove the Fuglede–Putnam type theorems when the adjoint of T ∈ B (K) is either (p, k)‐quasihyponormal or dominant or a spectral operator (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Cooperativity in the Conformational Rearrangements of Polymer Chain Segments as Seen by Bond Fluctuation Model
Authors: Torregrosa Cabanilles Constantino , Meseguer Dueñas José María , Gómez Ribelles José Luis , Molina‐Mateo José 
Published: June 2009

AbstractThe kinetics of structural relaxation was simulated using the bond fluctuation model. Annealing of the system in the glassy state produces a clearly nonexponential decrease in the energy in a certain temperature interval. At lower temperatures, the decrease in energy takes place by successive small steps, due to the change of the energy of individual polymer chains that modify their conformation into small neighbourhoods. This cooperativity is behind the nonexponential behaviour shown by structural relaxation at higher temperatures. A second order Markov chain is able to reproduce the nonexponentiality with quite good agreement with the bond fluctuation simulated curves. Cooperativity comes from the fact that the transition probability of a polymer chain between two energy levels depends on the history of previous transitions that took place in its neighbourhood.magnified image
Activation of p53/p21/PUMA alliance and disruption of PI‐3/Akt in multimodal targeting of apoptotic signaling cascades in cervical cancer cells by a pentacyclic triterpenediol fromBoswellia serrata
Authors: Bhushan Shashi , Malik Fayaz , Kumar Ajay , Isher Harpreet Kaur , Kaur Indu Pal , Taneja Subhash Chandra , Singh Jaswant 
Published: June 2009

AbstractCervical carcinoma is a growing menace to women health worldwide. This study reports the apoptotic cell death in human cervical cancer HeLa and SiHa cells by a pentacyclic triterpenediol (TPD) fromBoswellia serrataby a mechanism different from reported in HL‐60 cells. It caused oxidative stress by early generation of nitric oxide and reactive oxygen species that robustly up regulated time‐dependent expression of p53/p21/PUMA while conversely abrogating phosphatidylinositol‐3‐kinase (PI3K)/Akt pathways in parallel. TPD also decreased the expression of PI3K/pAkt, ERK1/2, NF‐κB/Akt signaling cascades which coordinately contribute to cancer cell survival through these distinct pathways. The tumor suppressor p53 pathway predominantly activated by TPD further up‐regulated PUMA, which concomitantly decreased the Bcl‐2 level, caused mitochondrial membrane potential loss with attendant translocation of Bax and drp1 to mitochondria and release of pro‐apoptotic factors such as cytochromecand Smac/Diablo to cytosol leading to caspases‐3 and ‐9 activation. In addition both the phospho‐p53 and p21 were found to accumulate heavily in the nuclear fraction with attendant decrease in topoisomarase II and survivin levels. On the contrary, TPD did not affect the extrinsic signaling transduction pathway effectively through apical death receptors. Interestingly,N‐acetyl cysteine, ascorbate and s‐methylisothiourea (sMIT) rescued cells significantly from TPD induced DNA damage and caspases activation. TPD may thus find usefulness in managing and treating cervical cancer. © 2009 Wiley‐Liss, Inc.
Structure elucidation and complete NMR spectral assignments of new furostanol glycosides from Solanum torvum
Authors: Lu Yuanyuan , Luo Jianguang , Kong Lingyi 
Published: June 2009

AbstractTwo new furostanol glycosides, torvosides O (1) and P (2), were isolated from leaves of Solanum torvum. Their structures were completely and unambiguously assigned by one‐ and two‐dimensional NMR techniques (1H NMR, 13C NMR, TOCSY, HSQC, ROESY and HMBC), ESI‐MS spectrometry and chemical methods. Copyright © 2009 John Wiley & Sons, Ltd.
Elasto‐plastic analytical model for the design of grouted bolts in a Hoek–Brown medium
Authors: Osgoui Reza. R. , Oreste Pierpaolo 
Published: June 2009

AbstractThis paper presents an elasto‐plastic analytical solution of an axi‐symmetrical problem for a circular tunnel reinforced by grouted bolts. Considered as the improved model of Indraratna and Kaiser (Int. J. Rock. Mech. Min. Sci. Geomech. Abstr. 1990; 27:269–281; Int. J. Numer. Anal. Meth. Geomech. 1990; 14:227–251), in proposed solution the rock mass obeys the non‐linear Hoek–Brown yield criterion (version 2002) in terms of its peak and residual strength parameters (the most spread strength criterion for the rock masses). The proposed approach considers a⩾0.5 for the rock mass and is based on the assumption that after the peak strength of the rock is reached, the material loses its strength, as dictated by a strength loss parameter. The strength loss parameter makes it possible to model either elastic–perfectly plastic or elastic–brittle–plastic behaviour. Because of the mathematical complexity, numerical treatments have been used to assist the solution in order to evaluate the equilibrium and compatibility equations. The concept of equivalent material for Hoek–Brown strength parameters is introduced to describe the rock mass improvement due to bolting effect. The results of the numerical analyses reveal a linear relation between the improved Hoek–Brown strength parameters and residual ones, taking into consideration the bolt density parameter (β). The proposed solution is able to analyse the stress and displacement state in the presence of a bolting intervention with the objective of improving the degree of stability of the rock around the tunnel. Descriptive applications of the derived elasto‐plastic solutions are also presented to explain the effectiveness of the grouted bolts in convergence reduction. Evidences obtained by numerical analysis verify the analytical solution. Copyright © 2009 John Wiley & Sons, Ltd.
A compact local one‐dimensional scheme for solving a 3D N‐carrier system with Neumann boundary conditions
Authors: Dai Weizhong 
Published: June 2009

AbstractWe consider a mathematical model for thermal analysis in a 3D N‐carrier system with Neumann boundary conditions, which extends the concept of the well‐known parabolic two‐step model for micro heat transfer. To solve numerically the complex system, we first reduce 3D equations in the model to a succession of 1D equations by using the local one‐dimensional (LOD) method. The obtained 1D equations are then solved using a fourth‐order compact finite difference scheme for the interior points and a second‐order combined compact finite difference scheme for the points next to the boundary, so that the Neumann boundary condition can be applied directly without discretizing. By using matrix analysis, the compact LOD scheme is shown to be unconditionally stable. The accuracy of the solution is tested using two numerical examples. Results show that the solutions obtained by the compact LOD finite difference scheme are more accurate than those obtained by a Crank‐Nicholson LOD scheme, and the convergence rate with respect to spatial variables is about 2.6. © 2009 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq 2010
Fast Legendre spectral method for computing the perturbation of a gradient temperature field in an unbounded region due to the presence of two spheres
Authors: Chowdhury A. , Christov C. I. 
Published: June 2009

AbstractThe temperature distribution around two spheres is considered when the main field has a constant gradient at infinity. Bispherical coordinates are used, together with a transformation of the dependent variable that leads to separation of variables. Then the solution can be sought in Legendre series with respect to one of the bispherical coordinates. An important element of the proposed work is the effective way to reduce an essentially 3D problem to a set of three 2D problems. The Legendre spectral method is shown to have an exponential convergence which is confirmed by the computations. The efficiency is so high that even for the hard cases of two closely situated spheres, an accuracy of 10−10 is achieved with as few as 20 terms in the expansion.Solutions with both longitudinal and transverse gradients at infinity are obtained, and the contour lines of the temperature field are presented graphically. © 2009 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq 2010
Effect of noise on the pattern formation in an epidemic model
Authors: Sun Gui‐Quan , Li Li , Jin Zhen , Li Bai‐Lian 
Published: June 2009

AbstractWe present novel numerical evidence of complicated phenomenon controlled by noise in a spatial epidemic model. The number of the spot is decreased as the noise intensity being increased, which we show by performing a series of numerical simulations. Moreover, when the noise intensity and temporal correlation are both large enough, the model dynamics exhibits a noise controlled transition from spotted pattern to stripe growth. In addition to that, we show in details the number of the spotted and stripe pattern, with the identification of a wide range of noise intensity and temporal correlation. The obtained results show that noise plays an important role in the pattern formation of the epidemic model, which may provide guidance to prevent and control the spread of disease. © 2009 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq 2010
Numerical solution of a class of complex differential equations by the Taylor collocation method in elliptic domains
Authors: Sezer Mehmet , Tanay Bekir , Gülsu Mustafa 
Published: June 2009

AbstractAn approximate method for solving higher‐order linear complex differential equations in elliptic domains is proposed. The approach is based on a Taylor collocation method, which consists of the matrix represantation of expressions in the differential equation and the collocation points defined in an elliptic domain. Illustrative examples are included to demonstrate the validity and applicability of the technique. © 2009 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq 2010
Numerical simulations of the improved Boussinesq equation
Authors: Irk Dursun , Dağ İdris 
Published: June 2009

AbstractIn this study, numerical simulations of the improved Boussinesq equation are obtained using two finite difference schemes and two finite element methods, based on the second‐and third‐order time discretization. The methods are tested on the problems of propagation of a soliton and interaction of two solitons. After the L∞ error norm is used to measure differences between the exact and numerical solutions, the results obtained by the proposed methods are compared with recently published results. © 2009 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq 2010