bluuebunny/crossref_metadata_2025 huggingface dataset:
Probing peptide libraries from Conus achatinus using mass spectrometry and cDNA sequencing: identification of δ and ω‐conotoxins
Authors: Gowd Konkallu Hanumae , Dewan Kalyan Kumar , Iengar Prathima , Krishnan Kozhalmannom S. , Balaram Padmanabhan
Published: February 2008

The peptide library present in the venom of the piscivorous marine snail Conus achatinus has been probed using a combination of mass spectrometry and cDNA sequencing methods. Matrix assisted laser desorption ionization mass spectrometry (MALDI‐MS) analysis, before and following global reduction/alkylation of peptide mixtures, permits the rapid classification of individual components on the basis of the number of disulfide bonds. Mass fingerprinting and the reverse phase HPLC retention times permit a further deconvolution of the library in terms of peptide size and hydrophobicity. Sequencing of cDNA derived using O‐superfamily specific primers yielded five complete conotoxin precursor sequences, ranging in polypeptide length from 75–87 residues containing six Cys residues at the C‐terminus. Sequence analysis permits classification of the five putative mature peptides (Ac 6.1 to Ac 6.5) as δ, ω, and ω‐like conotoxins. The presence of these predicted peptides in crude venom was established by direct matrix assisted laser desorption ionization tandem mass spectrometry (MALDI‐MS/MS) sequencing following trypsin digestion of the peptide mixture after global reduction/alkylation. The determination of partial peptide sequences and comparison with the predicted sequences resulted in the identification of four of the five predicted conotoxins. The characterization of posttranslationally modified analogs, which are hydroxylated at proline or amidated at the C‐terminus is also demonstrated. Crude venom analysis should prove powerful in studying both inter‐ and intra‐species variation in peptide libraries. Copyright © 2008 John Wiley & Sons, Ltd.
An investigation of the homolytic saccharide cleavage of deprotonated flavonol 3‐O‐glycosides in a quadrupole ion trap mass spectrometer
Authors: Davis Barry D. , Brodbelt Jennifer S.
Published: February 2008

The trend in the extent of homolytic saccharide cleavage is reported for a series of deprotonated flavonol 3‐O‐glycosides upon collision‐induced dissociation (CID) in a quadrupole ion trap mass spectrometer. The second‐generation product ions from the primary [Y0]− and [Y0− H]−• product ions were also identified. It was determined that the structure of both the aglycon and the saccharide portions of the flavonoid glycoside are pivotal in inducing radical cleavage. In contrast to earlier work on this subject reported for a smaller group of flavonols, the correlation between the degree of B‐ring hydroxylation and the extent of radical saccharide cleavage showed several notable exceptions in the present work. Homolytic cleavage was also investigated in the context of using tandem mass spectrometry to identify the aglycon portions of flavonoid glycosides. Copyright © 2008 John Wiley & Sons, Ltd.
Derivatization of β‐dicarbonyl compound with 2,4‐dinitrophenylhydrazine to enhance mass spectrometric detection: application in quantitative analysis of houttuynin in human plasma
Authors: Duan Xiaotao , Zhong Dafang , Chen Xiaoyan
Published: February 2008

Houttuynin (decanoyl acetaldehyde), a β‐dicarbonyl compound, is the major antibacterial constituent in the volatile oil of Houttuynina cordata Thunb. In the present work, detection of houttuynin in human plasma based on the chemical derivatization with 2,4‐dinitrophenylhydrazine (DNPH) coupled with liquid chromatography/tandem mass spectrometry was described. The primary reaction products between the β‐dicarbonyl compound and DNPH in aqueous phase were identified as heterocyclic structures, of which the mass spectrometric ionization and fragmentation behavior were characterized with the aid of high‐resolution multistage mass spectral analysis. For quantification, houttuynin and internal standard (IS, benzophenone) in plasma were firstly converted to their DNPH derivatives without sample purification, then extracted from human plasma with n‐hexane and detected by liquid chromatography tandem mass spectrometry performed in selected reaction monitoring (SRM) mode. This method allowed for a lower limit of quantification (LLOQ) of 1.0 ng/ml using 100‐µl plasma. The validation results showed high accuracy (%bias < 2.1) and precision (%CV < 7.2) at broad linear dynamic range (1.0–5000 ng/ml). The simple and quantitative derivatization coupled with tandem mass spectrometric analysis facilitates a sensitive and robust method for the determination of plasma houttuynin in pharmacokinetic studies. Copyright © 2008 John Wiley & Sons, Ltd.
Selection of lactic acid bacteria for acidification of brown juice (grass juice), with the aim of making a durable substrate for L‐lysine fermentation
Authors: Thomsen Mette H , Kiel Pauli
Published: February 2008

BACKGROUND: Brown juice is a waste product from the green crop‐drying industry. Heating and pressing of green crops prior to drying produces a juice rich in nutrients, which can be converted to a stable universal fermentation medium by lowering its pH to 4.0–4.5 via lactic acid fermentation. The aim of this study was to select a strain of lactic acid bacteria for industrial acidification of brown juice.

RESULTS: Several strains were tested in fermentation experiments and Lactobacillus salivarius ssp. salivarius DSM 20555 was found to be the best choice. It showed high growth rates at temperatures ranging from 40 to 48 °C, with an optimum temperature of 46 °C (µmax = 2.2 h−1), and maintained a high productivity at pH 4.0 in continuous fermentation. The highest productivity of 7.23 g L−1 h−1 was found at a dilution rate of 1.0 h−1.

CONCLUSION: With today's increased focus on utilisation of residues from food and agro‐industry, coupled with restrictions on their use as fertiliser for farmlands, lactic acid fermentation could play a significant role in conservation of these nutrient‐rich liquids. This study shows that Lb. salivarius ssp. salivarius DSM 20555 is a very promising micro‐organism for use in such a process. Copyright © 2008 Society of Chemical Industry
Endogenous adipose tissue as a hemostatic: Use in microsurgery
Authors: Akelina Yelena , Danilo Peter
Published: February 2008

Bleeding is a frequent complication of microsurgical repair of small blood vessels and time is spent while hemostasis is accomplished. We studied the hemostatic effect of endogenous adipose tissue on bleeding from rat femoral arterial anastomoses. We measured bleeding time (time from removal of clamps to cessation of active bleeding) and mean arterial blood velocity (using a micro‐Doppler system), the latter immediately after anastomosis, and again 7 days post‐anastomosis. Bleeding time for vessels with fat applied to the artery was 50% less than when no fat was applied. Blood velocity by day 7 post‐anastomosis returned to values equivalent to those for intact arteries. Histological evaluation of the anastomotic site demonstrated no significant differences in inflammatory response between fat‐treated and untreated arteries. These data suggest that endogenous adipose tissue may be a useful hemostatic agent devoid of significant effects on small artery blood velocity or histology. © 2008 Wiley‐Liss, Inc. Microsurgery, 2008.
Establishment of duodenojejunal bypass surgery in mice: A model designed for diabetic research
Authors: Liu Wei , Zassoko Roman , Mele Tina , Luke Patrick , Sun Hongtao , Liu Weihua , Garcia Bertha , Jiang Jifu , Wang Hao
Published: February 2008

We have developed a mouse duodenojejunal bypass (DJB) surgical model that is for studying the effects of bariatric surgery on glucose homeostasis and has potential to impact clinical therapy of diabetes. The operation consists of using the majority of the duodenum and proximal part of the jejunum for biliopancreatic diversion. The distal end of the jejunum is anastomosed in an end‐to‐end fashion to the remaining proximal end of the duodenum just distal to the pylorus. The biliopancreatic secretions are diverted into the distal jejunum through an end‐to‐side anastomosis. We performed 10 DJB operations in C57BL/6 mice, with a 100% survival rate. The surgery had no effect on the growth or feeding patterns of the animals. The intestinal mucosa showed normal histology and function. This study confirms that it is technically possible to perform DJB surgery in mice. This mouse model can be used in the study of surgical treatment for type II diabetes. © 2008 Wiley‐Liss, Inc. Microsurgery, 2008.
Recording and stimulating properties of chronically implanted longitudinal intrafascicular electrodes in peripheral fascicles in an animal model
Authors: Zheng Xiujun , Zhang Jian , Chen Tongyi , Chen Zhongwei
Published: February 2008

The purpose of this experiment was to study the recording and stimulating properties, and biocompatibility of longitudinally implanted intrafascicular electrodes (LIFEs) in a rabbit sciatic nerve model when they were chronically implanted into peripheral fascicles. LIFEs were implanted chronically into sciatic nerve fascicles of rabbits as recording and stimulating electrodes. Motor‐evoked potentials (MEPs) and cortical somatosensory‐evoked potentials (CSEPs) were recorded by using a transcranial stimulation system (TCS) over 6‐month period to observe the change of the signals recorded. At the end of the experiment, the fascicles at the electrodes implanted site were anatomized for histological examination under light microscope and transmission electron microscope. Results showed onset latency (OL) of MEPs and CSEPs had no obvious change during the first month. However, OL significantly increased during the second month, and then became stable 3 months after implantation. The interpeak amplitudes (IPAs) of MEPs had no distinct change during the first month, but significantly decreased over the next period, and then became stable 3 months after implantation. The IPAs of CSEPs, however, decreased slowly over the 6‐month period of the study. At the end of the experiment, histological examination indicated that a typical foreign body reaction developed, and electrodes caused mild damage to the fascicles, though inflammatory cells and neuroma were not seen around the electrodes. In conclusion, LIFEs have excellent recording and stimulating characters in addition to biocompatibility with peripheral fascicles. They can be implanted chronically into fascicles and record signals. © 2008 Wiley‐Liss, Inc. Microsurgery, 2008.
Magnetism in high‐contrast dielectric photonic crystals
Authors: Lepetit T. , Akmansoy É.
Published: February 2008

Photonic crystals made of high‐permittivity ferroelectric materials exhibit a resonant magnetic response in the microwaves range, leading to a effective permeability of a few tens or a negative relative effective permeability due to the enhancement of zeroth‐order Mie resonances. This effective permeability decreases when the filling factor tends toward 1. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 909–911, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23227
Printed symmetric inverted‐F antenna with a quasi‐isotropic radiation pattern
Authors: Cho Chihyun , Choo Hosung , Park Ikmo
Published: February 2008

This article presents a tag antenna with a quasi‐isotropic radiation pattern operating in the UHF band to eliminate the shadow zone in RFID systems. The proposed tag antenna has a symmetric inverted‐F structure with a bent section and is printed on a 50 μm‐thick PET substrate for easy and low‐cost fabrication. The detailed design parameters of the antenna were optimized using a Pareto genetic algorithm in conjunction with the IE3D EM simulator. The optimized antenna shows 3.2% fractional bandwidth for S11 < −10 dB, more than 87% efficiency in the operating frequency band, and less than 6 dB gain deviation. The measured reading range between the tag and reader is between 1.4 and 2.2 m. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 927–930, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23247
Reduced size small dual and multi‐frequency microstrip antennas
Authors: Bhunia S. , Sarkar D. , Biswas S. , Sarkar P. P. , B. Gupta  , Yasumoto K.
Published: February 2008

This study presents theoretical and experimental investigations on novel, compact, single layer and single probe‐fed rectangular microstrip patch antennas for dual and multi frequency operation. The novel design is achieved by cutting two rectangular slots at one side of the patch antenna. Compared with the conventional rectangular patch antenna, our antenna can achieve reduction in patch size up to 85%. Dual frequency operation has also been achieved effectively by just adjusting the feed position of a conventional rectangular patch antenna. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 961–965, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23255
Analysis of broad band U‐slot microstrip patch antenna
Authors: Ansari J. A. , Brij Ram Ram
Published: February 2008

A broad band U‐slot microstrip patch antenna on a single layer foam substrate is investigated using equivalent circuit concept. A parametric study has been carried out to investigate the effects caused by arm length, base length, and slot width of the U‐slot. The effects of substrate height and feed position are also analyzed to obtain the optimum values for broadband operation. Broadband (bandwidth 33.52%) enhancement of the antenna is achieved by inserting U‐slot into the patch. A comparison between theoretical and simulated results is also presented. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 1069–1073, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23274
A compact narrowband HTS filter with an extended upper stopband
Authors: Jin Shichao , Wei Bin , Zhang Xiaoping , Cao Bisong , Guo Xubo , Peng Huili , Gao Baoxin
Published: February 2008

In this article, a novel split‐end stepped impedance resonator (SESIR) has been proposed to relocate its first spurious resonant frequency. A three‐pole high temperature superconducting filter made up of SESIRs with a 0.4% bandwidth centered at 2423 MHz is developed. The filter has an extended stopband up to three times of the fundamental frequency. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 1066–1069, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23275
Erratum: Electromagnetic propagation in unbounded inhomogeneous chiral media using the coupled mode method
Authors: Gómez Álvaro , Barba Ismael , Cabeceira Ana C. L. , Represa José , Vegas Angel , Grande Ana , Solano Miguel Ángel
Published: February 2008

© 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 1132, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23280
An accelerating technique for analyzing open‐ended rectangular waveguides
Authors: Tan Weihua , Shen Zhongxiang
Published: February 2008

An accelerating technique for calculating the reflection coefficient matrix of an open‐ended rectangular waveguide with infinite flange is proposed in this paper. The matrix equation, which contains double surface integrals, is initially established using the mode‐matching method. To improve the computation efficiency, the double surface integral is converted to one surface integral in the spectral domain using the Sommerfeld identity. Then the matrix pencil method and the Gaussian quadrature are employed to accelerate the computation of the matrix elements, which results in the summation of a short series. An open‐ended WR‐90 waveguide model is analyzed to demonstrate the efficiency of the method in the calculation of the reflection coefficients. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 1061–1066, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23283
Compact stepped‐impedance lowpass filter with a slot‐back microstrip line
Authors: Huang Shao Ying , Lee Yee Hu
Published: February 2008

A high‐performance stepped‐impedance low‐pass filter is proposed by using a microstrip line with a longitudinal slot in the ground plane (slot‐back microstrip line). The design process is simple and yet effective in improving the performance of the filter structure. Expressions are proposed to obtain the characteristic impedance of a slot‐back microstrip line. Because of the high characteristic impedance and slow‐wave effect of a slot‐back microstrip line, the proposed filter shows a sharper cutoff and a wider stopband with higher attenuation within a smaller circuit area when compared with a conventional stepped‐impedance low‐pass filter. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 1058–1061, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23284
Analysis on characters of sub‐millimeter wave attenuation by rain medium
Authors: Zhu Li , Li Xing‐Guo , Lou Guo‐Wei
Published: February 2008

The attenuation of sub‐millimeter wave by rain medium is related to raindrops' spectrum and attenuation cross‐section. It is established about the model of raindrop attenuation cross‐section based on MP raindrop size distribution. The attenuation curves are described in 360, 400, and 480 GHz. The results show the model's parameters are in good agreement with the references. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 1025–1028, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23286
Slot‐loaded shorted patch for dual‐band operation
Authors: Kumar Singh Amit , Kumar Meshram Manoj
Published: February 2008

A dual‐band slot‐loaded shorted rectangular microstrip antenna is proposed and investigated both theoretically and experimentally. The dual‐band characteristic of antenna is achieved by incorporating a shorting‐pin on the left edge of the patch and thin slot. Numerical results for the input impedance, Return loss, and radiation patterns are presented and compared with the measured results. Good agreement is obtained between computed and measured results. Frequency tunability ranges from 1.39 to 1.44 GHz (about 50.0 MHz) for lower resonance and from 4.37 to 4.44 GHz (70.0 MHz) for upper resonance are observed. The frequency ratios of about 3.0 for the two operating frequencies are obtained. By loading the slot and shorting pin on the patch the antenna size is reduced up to 37%. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 1010–1017, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23300
Importance of forkhead transcription factor Fkhl18 for development of testicular vasculature
Authors: Sato Yuko , Baba Takashi , Zubair Mohamad , Miyabayashi Kanako , Toyama Yoshiro , Maekawa Mamiko , Owaki Akiko , Mizusaki Hirofumi , Sawamura Tatsuya , Toshimori Kiyotaka , Morohashi Ken‐Ichirou , Katoh‐Fukui Yuko
Published: February 2008

Forkhead transcription factors are characterized by a winged helix DNA binding domain, and the members of this family are classified into 20 subclasses by phylogenetic analyses. Fkhl18 is structurally unique, and is classified into FoxS subfamily. We found Fkhl18 expression in periendothelial cells of the developing mouse fetal testis. In an attempt to clarify its function, we generated mice with Fkhl18 gene disruption. Although KO mice developed normally and were fertile in both sexes, we frequently noticed unusual blood accumulation in the fetal testis. Electron microscopic analysis demonstrated frequent gaps, measuring 100–400 nm, in endothelial cells of blood vessels. These gaps probably represented ectopic apoptosis of testicular periendothelial cells, identified by caspase‐3 expression, in KO fetuses. No apoptosis of endothelial cells was noted. Fkhl18 suppressed the transcriptional activity of FoxO3a and FoxO4. Considering that Fas ligand gene expression is activated by Foxs, the elevated activity of Foxs in the absence of Fkhl18 probably explains the marked apoptosis of periendothelial cells in Fkhl18 KO mice. Mol. Reprod. Dev. 75: 1361–1371, 2008. © 2008 Wiley‐Liss, Inc.
ALSFRS and appel ALS scores: Discordance with disease progression
Authors: Voustianiouk Andrei , Seidel Gregory , Panchal Janki , Sivak Mark , Czaplinski Adam , Yen Albert , Appel Stanley H. , Lange Dale J.
Published: February 2008

Progression of disease and effectiveness of therapy in patients with amyotrophic lateral sclerosis (ALS) are determined by both questionnaire‐ and examination‐based measures. To determine whether both types of measurement tools are equally predictive at all stages of disease, we compared questionnaire‐based ALS Functional Rating Scale (ALSFRS) scores to the examination‐based Appel ALS (AALS) scores at different stages of disease. Same‐day scores were obtained during 174 visits in 62 patients with definite or probable ALS. Using normalized scores, correlation between the scales and predictability were best in mildly affected patients. Predictions of ALSFRS based on AALS scores were less than half as precise in the later stages of disease. Both scales showed significant change with disease progression, but ALSFRS consistently underestimated disease severity defined by AALS (P < 0.001). Questionnaire‐based measurements should be compared against objective scales at all stages of disease severity before they are accepted as primary endpoint measures. Muscle Nerve, 2008
Determination of tripdiolide in root extracts of Tripterygium wilfordii by solid‐phase extraction and reversed‐phase high‐performance liquid chromatography
Authors: Ma Jun , Schmidt Barbara M. , Poulev Alexander , Raskin Ilya
Published: February 2008

Extracts of Tripterygium wilfordii Hook F. have been widely used in China to treat a variety of autoimmune and inflammatory diseases. The diterpenoids triptolide and tripdiolide are two major active components in the T. wilfordii ethyl acetate extract. An efficient solid‐phase extraction and high‐performance liquid chromatography (SPE‐HPLC) method to measure triptolide content in the extract has been previously reported. However, a suitable means of tripdiolide quantification is not available because of interfering compounds in the extract that co‐elute with tripdiolide. Therefore, this paper describes a method wherein tripdiolide content can be measured from a small amount of the extract. The extract solution (600 µL) was applied into an aminopropyl SPE tube. Triptolide was eluted with dichloromethane:methanol (1 mL, 49:1 v/v), followed by tripdiolide elution with dichloromethane:methanol (3 mL, 17:3 v/v). The tripdiolide eluate was analysed by HPLC using an isocratic solvent system and was quantified by measuring the peak area at 219 nm. The contents of triptolide and tripdiolide in the extract were determined to be 807.32 ± 51.94 and 366.13 ± 17.21 µg/g of extract, respectively. Since tripdiolide is biologically active and makes up a considerable portion of the extract, for extract quality control and standardisation purposes, it should be measured along with triptolide using the proposed SPE‐HPLC method. Copyright © 2008 John Wiley & Sons, Ltd.
Micromagnetic model of magnetization reversal driven by spin‐polarized current in MgO‐based magnetic tunnel junctions
Authors: Finocchio G.
Published: February 2008

This paper describes the theoretical approach to model the magnetization reversal in magnetic tunnel junction with elliptical cross sectional area based on MgO tunnel barrier. The effects of the defects in the shape sample (computed directly by SEM images) and the presence of a pinhole in the tunnel barrier have been studied. The main results are: (i) the presence of the defects changes the coercive field of the free layer and the average value of the magnetostatic coupling with the pinned layer by less than 10%; (ii) the reversal mechanism driven by the magnetic field can be well described by macrospin approximation for all the non‐ideal shape simulated; (iii) the reversal driven by spin‐polarized current occurs via a nucleation process which is different with respect to the ideal ellipse in existence of a pinhole or defects. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Excitons and trions in cylindrical nanowires with dielectric mismatch
Authors: Slachmuylders A. F. , Partoens B. , Magnus W. , Peeters F. M.
Published: February 2008

We investigated the energy levels of excitons (X) and trions (X±) in free‐standing nanowires with strong lateral carrier confinement. Within the adiabatic approximation the two (resp. three) particle problem reduces to an effective one (resp. two) dimensional Schrödinger equation for the relative motion which is solved numerically. Dielectric mismatch effects are taken into account that result in a distorted Coulomb interaction between the charged particles. We obtain the X and X± binding energies as function of the dielectric mismatch ratio. To obtain these energies, we constructed tractable analytical expressions for the effective potential in the wire which significantly reduces the amount of computational time. Furthermore, X and X± binding energies as function of the wire radius were calculated and fitted. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
IMaX: a polarimeter based on Liquid Crystal Variable Retarders for an aerospace mission
Authors: Uribe‐Patarroyo N. , Alvarez‐Herrero A. , Heredero R. L. , del Toro Iniesta J. C. , López Jiménez A. C. , Domingo V. , Gasent J. L. , Jochum L. , Martínez Pillet V. , The IMaX Team
Published: February 2008

IMaX is the Imaging Magnetograph eXperiment, an instrument part of the payload of SUNRISE, a stratospheric balloon mission in Antarctica. It is also the precursor of the Visible Imaging Magnetograph of the future ESA Solar Orbiter mission. It is essentially a diffraction‐limited imager that carries out spectropolarimetric measurements of high resolution (bandwidth of < 100 mÅ at 525.02 nm), and relates the polarimetric properties of the incoming light through a telescope with magnetic fields in the Sun, via the Zeeman effect. At the core of the instrument there are the polarization modulation components, two Liquid Crystal Variable Retarders (LCVRs). A demodulation efficiency is defined and used as the figure of merit, and it serves to find the theoretical optimum states for the LCVRs as well as to judge the quality of the pre‐flight calibration of the system. This calibration and the method used to optimize the actual efficiency is explained. Also, the space qualification of the LCVRs is presented, where ellipsometry played a major role in studying the effects of radiation, vacuum and temperature in the operation of the LCVRs. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Spectroscopic ellipsometry on photonic crystals made by self‐assembled dye‐doped P(S/HEMA) nanospheres
Authors: Schutzmann S. , Prosposito P. , Casalboni M. , Venditti I. , Russo M. V.
Published: February 2008

In the present work the use of Spectroscopic Ellipsometry (SE) for a direct and non‐destructive optical and structural characterization of opaline photonic crystals is demonstrated. The analysis is performed on self‐assembled dye‐doped polymer nanospheres deposited on glass substrates. We study two different polymers beads: PMMA (as well‐known reference material) and poly[styrene‐(co‐2‐hydroxyethyl metacrylate)] [P(S/HEMA)]. We show that SE allows to obtain information about all the most important optical and geometrical features of the photonic structure as the effective refractive index (neff), the refractive index modulation, the optical anisotropy, the air/sphere filling fraction, the layer distance and the size of nanospheres. Results are in very good agreement with those obtained by Scanning Electron Microscope (SEM) analysis and Bragg reflection spectroscopy. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
An auto‐focusing method for imaging ellipsometry system
Authors: Meng Y. H. , Chen S. , Jin G.
Published: February 2008

An auto‐focusing method based on the image brightness gradient sharpness function is presented for imaging ellipsometry system, in which the image plane of the thin‐film specimen is not perpendicular to the optical axis. The clear image of a specimen with large area is obtained by moving the imaging sensor in optical axis direction and around its sensitive surface centre successively. The experimental results demonstrate its feasibility. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Molecular dynamics simulations and hyperspherical mode analysis of NO in Kr crystals with the use of ab initio potential energy surfaces for the Kr‐NO complex
Authors: Castro Palacio Juan Carlos , Rubayo‐Soneira Jesús , Lombardi Andrea , Aquilanti Vincenzo
Published: February 2008

The dynamics of structural relaxation of NO doped Kr solids on electronic excitation of the NO molecule has been characterized by molecular dynamics simulations and by normal and hyperspherical mode analysis, with special emphasis on the effects of the anisotropy of the Kr–NO interaction which has been modeled by ab initio potential energy surfaces (PESs). The time evolution of the cage radius and the radial distribution function for the ground and excited states have been calculated for various orientations of the molecular axis with respect the Kr atom matrix with the NO molecule treated as a rigid rotor. The ab initio PESs, considered in previous work, seem to be too repulsive when compared with potentials fitted to spectroscopic data, and this is more evident for the first Ryberg state than for the ground state, where effects of potential anisotropy are less important. The first shell response shows a relative increase, up to ∼10%, of the excited state equilibrium radius with respect to that of the ground state, while experiments indicate that such an increase should be less than 5%. The kinetic energy power spectrum method, presented in a previous work, has been applied to the total kinetic energy T(t) and to two characteristic quantities of the hyperspherical mode analysis, the hyperradial energy Tρ(t) and the grand angular energy TΛ(t) for NO molecular axis orientations of 67° and 90°, respectively, which represent the cases of the largest and smallest lattice distortions in the radial distribution function (RDF) of the atoms in the matrix for the excited state. The band structures of the calculated frequency spectra reveal a blue shift with respect to the case of the isotropic potentials used previously, and this is connected to the different lattice equilibrium structures for 67° and 90° directions. © 2008 Wiley Periodicals, Inc. Int J Quantum Chem, 2008
Direct injection of whole blood for liquid chromatography/tandem mass spectrometry analysis to support single‐rodent pharmacokinetic studies
Authors: Ingelse Benno A. , Vogel Gerard , Botterblom Margriet , Nanninga Dennis , Ooms Bert
Published: February 2008

Mass spectrometric developments in the last decade enable (sub)nanomolar detection of drug compounds in biological matrices in a few microliters of blood. However, the sampling and especially the handling of these small blood volumes is not straightforward. We studied the feasibility of a recently developed ‘sorbent sampling technique’ to handle these small blood volumes and the application to support pharmacokinetic (PK) screening programs. This technique applies 5–10 µL of blood on a fibrous material packed into a cartridge. Blood samples absorbed on these cartridges are eluted directly, on‐line onto a solid‐phase extraction liquid chromatography/tandem mass spectrometry (SPE‐LC/MS/MS) system. It is shown that the sorbent sampling technique can be applied for a range of drug compounds. In spite of issues with recovery and sample clean‐up that need further improvement, the sorbent sampling technique provided similar data as compared to conventional analytics. The technique was successfully applied to derive kinetic data from individual mice, thereby decreasing the number of required mice for a PK study from 21 to 3. Copyright © 2008 John Wiley & Sons, Ltd.
Network‐based H∞ control for stochastic systems
Authors: Meng Xiangyu , Lam James , Gao Huijun
Published: February 2008

This paper investigates the problem of network‐based control for stochastic plants. A new model of stochastic time‐delay systems is presented where both network‐induced delays and packet dropouts are taken into consideration for a sampled‐data network‐based control system. This model consists of two successive delay components in the state, and we solve the network‐based H∞ control problem based on this model by a new stochastic delay system approach. The controller design for the sampled‐data systems is carried out in terms of linear matrix inequalities. Finally, we illustrate the methodology by applying these results to an air vehicle control problem. Copyright © 2008 John Wiley & Sons, Ltd.
Derivatization of amino groups by pentafluorobenzaldehyde (PFB) as observed by XPS and NEXAFS spectroscopy on spin coated 4,4′‐methylenebis(2,6‐diethylaniline) films
Authors: Yegen E. , Lippitz A. , Treu D. , Unger W. E. S.
Published: February 2008

A toluene solution of 4,4′‐methylenebis(2,6‐diethylaniline) was spin coated on Si wafers. The samples were derivatized with pentafluorobenzaldehyde (PFB) in order to determine the primary amino groups on the surface. XPS C 1s and N 1s and C and N K‐edge NEXAFS of underivatized and derivatized films were carefully analyzed. The result was that after 10 min of exposure the gas–surface reaction was already completed. A reasonable derivatization reaction yield in the order of 90% is derived from the experiments. This number correlates well to a reaction yield obtained by a wet chemical approach. Copyright © 2008 John Wiley & Sons, Ltd.
An experimental study of the electronic structure of anodically grown films on an amorphous Ni78Si8B14 alloy
Authors: Diplas S. , Knutsen T. , Jørgensen S. , Gunnæs A. E. , Våland T. , Norby T. , Olsen A. , Taftø J.
Published: February 2008

Films of Ni(OH)2 and NiOOH grown on a rapidly solidified amorphous Ni78Si8B14 alloy by anodic polarisation were analysed with XPS and the results were compared with those of NiO and of films grown on polycrystalline Ni. SIMS performed on the polarised alloy showed enrichment of Ni at the outermost surface. Transmission electron microscopy (TEM) of cross‐sectional samples showed an absence of crystallinity. The Ni 2p shake up satellite and valence band spectra suggested that NiOOH is characterised by a more enhanced n‐type semi‐conducting behaviour compared to Ni(OH)2 in agreement with earlier tunnelling current density measurements performed with scanning tunnelling spectroscopy (STS). Copyright © 2008 John Wiley & Sons, Ltd.
Origin of the redox deactivation phenomena in modified alumina‐supported Ce/Pr mixed oxide
Authors: Aboussaid Karima , Bernal Serafín , Blanco Ginesa , Cifredo Gustavo Aurelio , Galtayries Anouk , Pintado José María , el Begrani Mohamed Soussi
Published: February 2008

In this study, we have investigated the redox deactivation of a Ce/Pr mixed oxide supported on modified alumina. Two samples have been prepared by using silica‐ or lanthana‐modified alumina as supports: 25% Ce0.8Pr0.2O2−x/Al2O3‐SiO2 and 25% Ce0.8Pr0.2O2−x/Al2O3‐La2O3. The redox behavior was studied by reduction of the samples at selected temperatures, from 200 to 900 °C. Oxygen Storage Capacity (OSC) of reduced samples was measured by their reoxidation at 200 °C. The reduction degree attained by the supported mixed oxide, after reduction at temperatures up to 800 °C, increases in parallel for both samples. However, at 900 °C, there is a decrease of OSC, which is moderate for silica‐modified sample, while for lanthana‐modified catalyst, the OSC is almost negligible. XPS analysis of the fresh samples shows that the redox state of cerium cations close to the surface is mainly + 4, while praseodymium appears always as Pr3+. Samples reduced at different temperatures were also investigated by XPS. In the case of silica‐modified alumina reduced at 900 °C, significant amounts of Ce4+ can still be detected, which is in good agreement with the OSC value observed at that temperature. However, lanthana‐modified sample reduced at 800 °C shows an important amount of Ce3+, being the only oxidation state observed for cerium after reduction at 900 °C. This is in good agreement with the strong drop in OSC observed for this latter sample, which can be thus attributable to the trapping of trivalent cations by the alumina, forming a stable perovskite‐like aluminate, LnAlO3, as confirmed by X‐Ray Diffraction (XRD). Copyright © 2008 John Wiley & Sons, Ltd.
Surface modification of polymeric thin films with vacuum ultraviolet light
Authors: Sarantopoulou E. , Kovač J. , Kollia Z. , Raptis I. , Kobe S. , Cefalas A. C.
Published: February 2008

Spin‐coated poly(methyl methacrylate) (PMMA) thin films on SiO2 substrate were chemically modified with laser light at 157 nm in nitrogen. Film changes involve bond breaking of polymeric chains, etching, and surface morphological changes. The 157 nm photons mainly dissociate the CO, CO, and CH bonds, and catalyze the formation of new CN bonds. The surface roughness of the irradiated films was changed with the formation of elongated patterns. The film thickness during irradiation was reduced with the rate of 0.005 nm at 1 mJ/cm2. Furthermore, the PMMA film forms a thin interface layer with the SiO2 substrate. Its thickness was reduced following vacuum ultraviolet (VUV) irradiation due to photodissociation of molecules inside the interface layer. Copyright © 2008 John Wiley & Sons, Ltd.
Perspectives on dietary fat, cancer report
Authors: Reddy Bandaru S. , Heyden Siegfried , Carroll K. K. , Hill Michael
Published: February 2008

Conclusion

The lowering of blood cholesterol levels through changes in the fat quality which has proven beneficial in the prevention of heart attacks has had no undesirable side effects. Even more important, the reports on the frequency of cancer in the international dietary studies, between 1970 and 1982, have demonstrated a slight (and insignificant) reduction in cancer deaths, an unexpected bonus for adherence to a diet with less animal fat and more vegetable fats and oils.
An improved model for industrial vegetable oil hydrogenation
Authors: Moharir A. S. , Bhatia S. , Saraf D. N.
Published: February 2008

A simplified mathematical model has been used to describe industrial vegetable oil hydrogenation. The temperature dependence of the reaction rate constants is taken into account. Data collected from full‐scale hydrogenation units are used to evaluate the model param‐eters. A simple technique is suggested for parameter estimation.
Determination of ultratrace metals in hydrogenated vegetable oils and fats
Authors: Nash A. M. , Mounts T. L. , Kwolek W. F.
Published: February 2008

Ultratrace levels of nickel, chromium, copper and iron occurring in hydrogenated vegetable oil products were estimated by dispersion of the samples in 4 methyl‐2‐pentanone and atomic absorption analysis by the graphite furnace technique. The principal goals in establishing the analytical methods were improved sensitivity to metals at low levels and applicability to limited amounts of products. Using reproducibility and linearity of response as criteria, optimum oil concentration in solvent and instrument parameters were established. For a series of commercial products, the method of standard additions was adopted to correct for matrix differences between the products and salad oil‐based standards. The range for the metals was determined in five cooking oils: Ni, 29–207 ppb; Cr, 1–5 ppb; Cu, 13–37 ppb; and Fe, 138–301 ppb; in recovered oils from five margarines: Ni, 34–70 ppb; Cr, 2–12 ppb; Cu, 26–58 ppb; and Fe, 239–540 ppb; and in five solid shortenings: Ni, 592–2772 ppb; Cr, 8–35 ppb; Cu, 26–108 ppb.
Physical and chemical properties of randomly interesterified blends of soybean oil and tallow for use as margarine oils
Authors: Lo Y. C. , Handel A. P.
Published: February 2008

Refined, unhydrogenated soybean oil and edible beef tallow were interesterified with sodium methoxide. This was done as an alternative to hydrogenation for the production of plastic fats for use as margarine oils. Using 0.5% sodium methoxide at 80 C, interesterifi‐cation was complete in 30 min as determined by lipase hydrolysis. A blend of 60% soybean oil and 40% edible beef tallow was found to have physical characteristics (melting point, solid fat index) similar to those of commercial tub margarine oils. The level of poly‐unsaturated fatty acids was slightly lower and the level of saturated fatty acids slightly higher than the commercial margarine oils. Iodine value andtrans fatty acid determinations indicated no dis‐cernible effect on the degree of unsaturation or the level of isomeric fatty acids by the interesterification process. The interesterified blend did contain 3.0%trans fatty acids which were originally present in the tallow. Oxidative stability of the interesterified oils was estimated by peroxide value determinations over several days on samples stored at 60 C. Experimental blends treated with 0.1% citric acid had poorer stability than the partially hydrogenated margarine oils; however, 0.01% BHA significantly delayed oxidation of the experimental samples.
A time normalization study of the separation of olive oil triglycerides
Authors: Pauls R. E.
Published: February 2008

A brief study on the selection of the optimal mobile phase for the reversed‐phase liquid Chromatographic separation of olive oil trigly‐cerides was carried out using a time normalization approach. Two parameters, the solvents comprising the binary mobile phase and the proportion of strong solvent in the binary mixture, were simultane‐ously varied in order to maintain the retention time of the last com‐ponent of interest fixed. Seven binary mobile phases were examined in the study. Plots of log k′ against percent strong solvent were found to be linear for all seven solvent pairs. This allowed prediction of the solvent composition needed to produce a given k’. A mixture of di‐chloromethane/acetonitrile gave optimal resolution for the triglycer‐ides under study. This time normalization approach offers a simple method directly to study effects of the variation of experimental parameters upon resolution.
A rapid argentation tlc method for detection of reesterified oils in olive and olive‐residue oils
Authors: Gegiou D. , Georgouli M.
Published: February 2008

A rapid, simple and reproducible argentation thin layer Chromatog‐raphic method for the detection of reesterified oils in olive and olive‐residue oil is described. The sensitivity of the method is com‐parable to the sensitivity to the IUPAC method 2,210 for the determination of fatty acids in the 2‐position in the triglycerides of oils and fats.
The antioxidant activity of amino acids in two vegetable oils
Authors: Ahmad M. M. , Al‐Hakim S. , Adel A. , Shehata Y.
Published: February 2008

Of 27 amino acids studied, most had some antioxidant activity when added in aqueous solution to either safflower oil or a mixture of sunflower and cottonseed oil (active oxygen and storage methods). Cysteine‐HCl, glutamic acid‐HCl (in the mixture), and glutamic acid‐HCl (in safflower oil) behaved as prooxidants. When added as a solid, most amino acids were ineffective. The protection factors of these amino acids were less than 1.3 in safflower oil with methionine, proline, lysine and cysteine providing the highest activ‐ity. In the oil mixture (which had a higher metal content) lysine, arginine, glutamic acid, methionine, and hydroxyproline were anti‐oxidant with protection factors of up to 1.85. Chelation of metals by amino acids was presumably responsible for the antioxidant activity. The increase in cysteine concentration up to 1% has more than doubled the protection factor in Bint oil (compared with the 0.01% level), whereas with some other amino acids the increase was either small or slight.
Modification of sal fat (shorea robusta) and mowrah fat (madhuca latifolia) by methyl ester‐triglyceride interchange reactions
Authors: Bhattacharyya D. K. , Banerjee K.
Published: February 2008

Methyl ester‐triglyceride interchange reactions provide a convenient route for preparing palmitic and lauric acid‐rich Sal fat, and stearic and palmitic acid‐rich Mowrah fat, with altered triglycéride com‐positions and thermal properties. The products are new kinds of plastic fats and may be useful as extenders of cocoa butter, high stability bakery fat, vanaspati (unhydrogenated type), tropical margarine, etc.
Derivatization of keto fatty acids: II. synthesis of long‐chain enolacetates
Authors: Siddiqi S. F. , Ahmad Fasih , Siddiqi M. S. , Osman S. M.
Published: February 2008

Long‐chain enolacetates were prepared by refluxing the keto fatty acids with acetic anhydride andp‐toluene sulfonic acid (p‐TSA). 10‐Oxoundecanoic and 2‐oxohexadecanoic acids gave mainly 10‐acetoxy‐10‐undecenoic and 2‐acetoxy‐2‐hexadecenoic acids, respectively. On the other harld, 12‐oxooctadecanoic acid on similar treatment was assumed to yield an isomeric mixture of 12‐acetoxy‐12(11)‐octadecenoic acids. The structure of the individual reaction products were established by spectral studies.
Sucrose esters and sucrose ester/glyceride blends as emulsifiers
Authors: Gupta R. K. , James K. , Smith F. J.
Published: February 2008

The sucrose mono‐and diesters of long‐chain fatty acids form a class of food‐grade emulsifiers with a wide range of hydrophile‐lipophile balance (HLB) values. Blends of sucrose mono‐_and di‐tallowate show a linear relationship between HLB and composition over the HLB range 10–16. Using blends of mixed glycerides and sucrose tallowate, the HLB range from 4 to 16 can be covered. The relationship between HLB water‐solubility and composition in the sucrose esters is dependent on three factors: (a) the degree of sub‐stitution; (b) the alkyl chain length in the ester group; and (c) the presence of dienoic or trienoic acyl groups. Water‐solubility of the esters studied ranged from soluble to insoluble; sucrose esters with C12 or unsaturated acyl groups act as solubilizers. The relationship between fatty acid profile and solubility was studied using sucrose esters prepared from tallow, palm kernel oil, soybean oil and coconut oil. The properties required of a range of emulsifiers designed for use in foods, cosmetics and pharmaceuticals are: (a) that they cover the range of HLB from 2 to 16+; (b) that at high HLB values (16+), they act as solubilizers; (c) low toxicity and irri‐tancy. The sucrose esters, and sucrose ester/mixed glyceride blends, have the required combination of properties. The HLB range to 16+ can be covered without forming ethoxylated or propoxylated derivatives.
Safety of Alpha Olefin Sulfonates
Authors: Haar Gary Ter
Published: February 2008

Alpha olefin sulfonates (AOS) belong to the anionic surfac‐tant class. They are efficient, readily biodegradable cleaning agents. This paper reviews the safety aspects of AOS, in‐cluding acute toxicity, teratogenicity, animal sensitization, human sensitization, chronic toxicity and lifetime studies ‐cancer bioassay.