bluuebunny/crossref_metadata_2025 huggingface dataset:
Core–shell nanostructure and its phase transitions in Pb(Mg1/3Nb2/3)O3 by Raman spectroscopy and photoluminescence
Authors: Kesavamoorthy R. , Sivasubramanian V.
Published: April 2007

Raman scattering, photoluminescence, X‐ray and dielectric studies were carried out in phase‐pure relaxor ferroelectic Pb(Mg1/3Nb2/3)O3 (PMN) polycrystalline sample. Low‐wavenumber Raman scattering (LWRS) from surface acoustic phonon modes in the 5–40 cm−1 range was studied at various temperatures from 25 to 550 °C. These spectra support the hypothesis of the core–shell nanostructure with a 1:1 ordered negatively charged nanocore surrounded by a positively charged nanoshell. These surface acoustic modes exist even up to 550 °C, revealing the existence of the charged core–shell nanostructures, which is well beyond the dissolution temperature of the polar nanoclusters in this material. The diameter of the shell is predicted from the LWRS results as 2.9 nm for a 2 nm core. Optical Raman spectra of PMN from 20 to 1000 cm−1 at 10 and 300 K show overlapping, broad peaks. Deconvolution of the spectrum into 12 modes suggests that they may arise from a 1:1 ordered charged nanocore and polar nanoclusters. Temperature‐dependent photoluminescence (PL) spectra of PMN reveal structural phase transitions in the nanoshell. The temperature behavior of the 1.57, 1.67 and 1.73 eV PL bands indicates a phase transition at 110 K from one crystalline phase to another of the nanoshell. The anomalous behavior of the 1.73 eV band intensity at 210 K is attributed to a transition from the crystalline to the amorphous phase in the nanoshell at 210 K. Thermal quenching of the 1.67 eV PL emission predicts a phonon mode at 1153 cm−1, which is identified in the Raman measurement. Copyright © 2007 John Wiley & Sons, Ltd.
Raman spectroscopy of optical phonon confinement in nanostructured materials
Authors: Arora Akhilesh K. , Rajalakshmi M. , Ravindran T. R. , Sivasubramanian V.
Published: April 2007

If the medium surrounding a nano‐grain does not support the vibrational wavenumbers of a material, the optical and acoustic phonons get confined within the grain of the nanostructured material. This leads to interesting changes in the vibrational spectrum of the nanostructured material as compared to that of the bulk. Absence of periodicity beyond the particle dimension relaxes the zone‐centre optical phonon selection rule, causing the Raman spectrum to have contributions also from phonons away from the Brillouin‐zone centre. Theoretical models and calculations suggest that the confinement results in asymmetric broadening and shift of the optical phonon Raman line, the magnitude of which depends on the widths of the corresponding phonon dispersion curves. This has been confirmed for zinc oxide nanoparticles. Microscopic lattice dynamical calculations of the phonon amplitude and Raman spectra using the bond‐polarizability model suggest a power‐law dependence of the peak‐shift on the particle size. This article reviews recent results on the Raman spectroscopic investigations of optical phonon confinement in several nanocrystalline semiconductor and ceramic/dielectric materials, including those in selenium, cadmium sulphide, zinc oxide, thorium oxide, and nano‐diamond. Resonance Raman scattering from confined optical phonons is also discussed. Copyright © 2007 John Wiley & Sons, Ltd.
An example of the complementarity of laser‐induced breakdown spectroscopy and Raman microscopy for wall painting pigments analysis
Authors: Bruder Romain , Detalle Vincent , Coupry Claude
Published: April 2007

Laser‐induced breakdown spectroscopy (LIBS) and Raman microscopy were used for the identification of pigments in wall painting. Raman spectroscopy, which provides the molecular ‘fingerprint’ of the compound, is nowadays widely used by the archaeometry community, especially for pigment analysis. LIBS, which provides the elementary composition of samples, is a rapid noncontact method, enabling layer‐by‐layer analysis through a precise laser ablation of the sample. This work deals with the behavior of pigments after a LIBS analysis, by trying to identify the compounds before and after the laser shot. Six commercial pigments prepared with the fresco technique were investigated: ultramarine blue, red lead, charcoal, a yellow and a red ochre, and a green earth. Raman spectra, acquired on the sample surface and in the crater induced by LIBS analysis, were compared. The results show that these pigments are well recognized after a LIBS measurement. The analysis of green earth illustrates that the combination of these two techniques gives complete information from a sample. Copyright © 2007 John Wiley & Sons, Ltd.
Monitoring oxidation of multiwalled carbon nanotubes by Raman spectroscopy
Authors: Osswald Sebastian , Havel Mickael , Gogotsi Yury
Published: April 2007

Multiwalled carbon nanotubes (MWCNTs) were oxidized in air and acids while varying the treatment time and/or temperature. The goal of this approach was to create the highest density of carboxyl groups with moderate sample loss, which is necessary for nanocomposite applications. In situ Raman experiments allowed real‐time observation of the structural changes in MWCNTs upon oxidation. The ratio of the Raman intensities of the D and G bands was used to estimate the concentration of defects. It was found that while an oxidation for 6 h in H2SO4/HNO3 provided the strongest effect, a ‘flash oxidation’ in air (15 min at 550 °C) also leads to an efficient functionalization in a cost‐effective and environmentally friendly way. Transmission electron microscopy, Fourier‐transform infrared (FTIR) spectroscopy, thermogravimetric analysis and electrophoretic mobility analysis were used to study the oxidized nanotubes. Copyright © 2007 John Wiley & Sons, Ltd.
Raman spectroscopy and molecular simulation investigations of adsorption on the surface of single‐walled carbon nanotubes and nanospheres
Authors: Amer Maher S.
Published: April 2007

Raman spectroscopy has, for long, been utilized to investigate material systems on the micro and mesoscales. Recently, the technique has proven its ability in exploring systems on the nanoscale. In this paper, we review our recent work on the Raman investigation of molecular adsorption from liquid mixtures on surfaces of single‐walled carbon nanotubes and fullerene nanospheres, emphasizing the following major research findings: the development of a Raman‐based technique capable of sensing local chemical interactions on the surface of carbon nanotubes and spheres; the molecular simulation results supporting the Raman investigation; the possibility of creating mesostructures based upon mixtures of carbon nanotubes and nanospheres that are crucial for selective adsorption. The current findings represent a major new thrust for the development of new nanostructured materials with superior adsorption capabilities and unique applications. Copyright © 2007 John Wiley & Sons, Ltd.
Polarizability calculation of vibrating nanoparticles for intensity of low wavenumber Raman scattering
Authors: Murray Daniel B. , Netting Caleb H. , Mercer Robin D. , Saviot Lucien
Published: April 2007

A new numerical method is introduced for calculating the polarizability of an arbitrary dielectric object with position‐dependent complex permittivity. The intended application of this is when the permittivity function depends on the instantaneous distortion of a vibrating nanoparticle. Three separate numerical approaches are provided to calculate the dipole moment of a nanoparticle embedded in a dielectric matrix in the presence of an applied electric field. Numerical tests confirm the accuracy of this method when applied to several cases for which an exact solution is available. This method is especially well suited for the calculation of absolute Raman scattering intensities due to acoustic phonons in metallic and dielectric nanoparticles embedded in transparent matrices. Copyright © 2007 John Wiley & Sons, Ltd.
Time‐resolved coherent Raman and sum‐frequency generation spectroscopy with wavelength‐tunable, short‐pulse, photonic‐crystal fiber light sources
Authors: Zheltikov A. M.
Published: April 2007

Photonic‐crystal fibers deliver frequency‐tunable radiation within the wavelength range stretching from the ultraviolet to the near‐infrared with output pulse widths from tens of femtoseconds to a few picoseconds and peak powers from a few watts to several megawatts, suggesting a convenient, efficient, and compact fiber format of short‐pulse sources for time‐resolved nonlinear spectroscopy and microscopy. Here, we examine the potential of photonic‐crystal fiber light sources for time‐resolved studies of ultrafast population and coherence relaxation dynamics in molecular systems using coherent anti‐Stokes Raman scattering and two‐photon‐resonant sum‐frequency generation. Copyright © 2007 John Wiley & Sons, Ltd.
Dual‐pump CARS measurements of N2, H2 and CO in a partially premixed flame
Authors: Weikl Markus C. , Seeger Thomas , Hierold Ruth , Leipertz Alfred
Published: April 2007

A three‐laser, dual‐pump coherent anti‐Stokes Raman scattering (CARS) technique for the simultaneous detection of nitrogen, carbon monoxide and hydrogen has been developed and tested. Hydrogen Q‐branch lines were used for the determination of relative hydrogen concentrations, which offers a much wider range of detectivity in contrast to approaches in which S‐branch transitions are used. Consequently, hydrogen concentrations could be measured over a whole range of temperatures, from room air to a flame. Measurements were taken in a heated cell and in a partially premixed propane/air flame. Measurements in the cell were in good agreement with theoretical spectral calculations. From measurements in the flame, the relative concentrations of hydrogen and carbon monoxide, which were generated as intermediate species, could be determined. Furthermore, diffusion effects of hydrogen could be observed with the presented approach. Copyright © 2007 John Wiley & Sons, Ltd.
Raman scattering of nanoporous semiconductors
Authors: Irmer Gert
Published: April 2007

The application of Raman scattering for characterizing porous semiconductors is reviewed. For structural units of only a few nanometers in size, as observed in por‐Si or por‐Ge, phonon confinement effects appear that can be used for size determinations. In polar porous semiconductors, surface‐related phonons (Fröhlich modes) between the TO and LO phonons appear. These surface phonons couple with the plasmons of free charge carriers in the porous medium. Examples are given of porous layers on III–V semiconductors in which Raman scattering is used to study charge carrier depletion. For theoretical treatment, the effective medium theory is used, taking into account the morphology with parallel pores or nanocolumns with radii down to a few tens of nanometers. Copyright © 2007 John Wiley & Sons, Ltd.
Rapid polymer blend imaging with quantitative broadband multiplex CARS microscopy
Authors: von Vacano Bernhard , Meyer Lars , Motzkus Marcus
Published: April 2007

Broadband multiplex coherent anti‐Stokes Raman scattering (MCARS) microscopy allows the rapid chemical mapping and molecular imaging of untreated material samples with three‐dimensional sectioning capabilities. It can be realized with a single laser in a simple and robust setup using supercontinuum generation in a microstructured fiber. The successful implementation of a MCARS microscope is discussed in detail, its parameters are characterized, and applications are shown for the identification and mapping of polymer blends. An evolutionary fitting routine is presented, which allows a fully quantitative analysis of the MCARS information resulting in high‐contrast chemical maps. The established setup enables reliable day‐to‐day operation as a valuable tool for rapid material characterization. Copyright © 2007 John Wiley & Sons, Ltd.
New approach to single‐shot CARS thermometry of high‐pressure, high‐temperature hydrocarbon flames
Authors: Fabelinsky V. I. , Smirnov V. V. , Stel'makh O. M. , Vereschagin K. A. , Vereschagin A. K. , Clauss W. , Oschwald M.
Published: April 2007

We demonstrate the feasibility of a proposed new approach to CARS thermometry with simultaneous measurements of the intensities of the hydrogen Q‐branch lines and their linewidths during a single laser shot by means of a spectrograph combined with an interferometer having orthogonal directions of dispersions. This allows correct temperature evaluation that takes into account the directly measured linewidths. The experiments were carried out in a H2:N2 = 1:10 mixture in a heated cell at a temperature of 1050 K. The values of the gas mixture temperature, which were defined from dual‐broad band (DBB) CARS spectra with linewidth corrections in a pressure range of 2–9 MPa, coincide with thermocouple measurements within ∼2%, while without such a correction, the discrepancies increase up to 5%. The proposed approach can be applied to CARS temperature measurements in investigations of H2 and hydrocarbon combustions without the necessity of species concentration measurements and not requiring the knowledge of line‐broadening coefficients. Copyright © 2007 John Wiley & Sons, Ltd.
Adiabatic climbing of vibrational ladders using Raman transitions with chirped pump lasers: effect of higher electronic surfaces and control of the shapes of vibrational wave packets
Authors: Tchitchekova Deyana S. , Chelkowski Szczepan , Bandrauk André D.
Published: April 2007

Using numerical solutions of the time‐dependent Schrödinger equation for the H2 molecule in intense laser fields we calculate the vibrational excitation induced by the Raman chirped adiabatic process (RCAP). We show that adding several higher electronic surfaces to a simple two‐surface model improves the efficiency of the ladder‐climbing process at intensities below the adiabaticity threshold. Furthermore, we show that although using photon energies close to the one‐photon electronic transition frequency allows the use of lower pump and Stokes intensities, in general, this leads to more population transfer to the upper electronic surfaces accompanied by a loss of selectivity in the vibrational excitation on the ground‐state surface. By contrast, considerable dissociation yields can be achieved when higher energy photons are used. We also investigate the structure of time‐dependant vibrational wave packets prepared by RCAP. We find that at specific times the wave packet is very well localised at large inter‐nuclear separations at which ionisation occurs with a probability 3 orders of magnitude larger than at the equilibrium separation. Copyright © 2007 John Wiley & Sons, Ltd.
Self‐assembled monolayers of mercaptosuccinic acid monolayers on silver and gold surfaces designed for protein binding. Part II: vibrational spectroscopy studies on cytochrome c immobilization
Authors: Królikowska Agata , Bukowska Jolanta
Published: April 2007

An attempt has been made for using MSA‐modified electrodes as linkage monolayers for electrostatic and covalent binding of cytochrome c (Cc). For MSA monolayers grown from an aqueous solution on Ag, attachment of Cc in its native state is proved in the case of covalent bonding. Electrostatic immobilization of Cc at pH 7 results in presence of at least some amount of Fe2+ high‐spin configuration and/or Fe3+ oxidation state. Native protein Fe2+ low‐spin state of Cc is observed after applying a negative potential to the Ag electrode. The influence of the solvent used for the preparation of the MSA monolayer and thiol surface coverage of the Ag surface was studied. It was shown that the key factor to obtain the native structure of Cc is the successful blocking of the metal surface by the MSA linking layer. IRRAS measurements of MSA on monocrystalline gold (111) at neutral pH confirm the successful electrostatic Cc immobilization, which preserves the Fe2+ oxidation state of the chromophore on this substrate. Copyright © 2007 John Wiley & Sons, Ltd.
Vibrational spectroscopic study of budesonide
Authors: Ali H. R. H. , Edwards H. G. M. , Kendrick J. , Munshi T. , Scowen I. J.
Published: April 2007

The Raman spectrum of budesonide is reported for the first time, and molecular assignments are proposed on the basis of ab initio BLYP DFT calculations with a 6‐31 G* basis set and vibrational wavenumbers predicted on a quasi‐harmonic approximation. Comparison with previously published infrared data has explained several spectral features, and the relative band intensities in the CO and CC stretching regions are interpreted. The results from this study provide data that can be used for the preparative process monitoring of budesonide, an important steroidal pharmaceutical in various dosage forms, and its interaction with excipients and other components. Copyright © 2007 John Wiley & Sons, Ltd.
Isoflavone profiles, phenol content, and antioxidant activity of soybean seeds as influenced by cultivar and growing location in Ohio
Authors: Riedl Ken M , Lee Jae Hwan , Renita Marjory , St Martin Steven K , Schwartz Steven J , Vodovotz Yael
Published: April 2007

Isoflavone levels and isoflavone chemical composition in soybeans vary between planting locations although the exact factors which control isoflavone biosynthesis are unclear. We compared levels of 12 isoflavones in soybean seeds of six cultivars grown in four different locations in Ohio in 2002 as determined by high‐performance liquid chromatography. Antioxidant activity contained in plant‐based foods can improve food oxidative stability and phenolics and isoflavones have proven active in food systems. Radical scavenging activity was assessed using the 2,2‐diphenyl‐1‐picrylhydrazyl (DPPH) radical. Total phenolics (TPCs) were determined by using Folin–Ciocalteu reagent. Total isoflavones (TIs) varied five‐fold (1573–7710 nmol g−1) between seeds from the various location–cultivar combinations. One location (Wooster, Ohio) produced seeds containing half the isoflavones as the other locations tested apparently due to poor growing conditions. The cultivars could be divided into two groups based on TI, one having approximately 50% more isoflavones. Surprisingly, across the entire data set, with increasing TI, the proportion of isoflavones accounted for by the daidzein family increased due primarily to malonyl daidzin. DPPH scavenging did not differ significantly by location or cultivar (P > 0.05) and did not correlate with TPC or TI. Profiling soybean isoflavones could help elucidate how isoflavone biosynthesis is regulated and lead to better disease resistance of soybean crops and soy foods with greater health benefits. Copyright © 2007 Society of Chemical Industry
Physicochemical properties of cassava, potato and jicama starches oxidised with organic acids
Authors: Martínez‐Bustos Fernando , Amaya‐Llano Silvia Lorena , Carbajal‐Arteaga J Antonio , Chang Yoon Kil , Zazueta‐Morales José de J
Published: April 2007

The oxidising effects of organic (acetic, citric and lactic) acids on the physicochemical properties of starches from cassava, potato and jicama were investigated. Cassava starch oxidised with lactic and citric acids had the highest carbonyl contents (5.43 and 5.84 g kg−1 respectively), while oxidised potato starch had the highest carboxyl contents. Oxidised jicama starch showed the lowest carbonyl and carboxyl contents. Oxidation increased the maximum viscosity of cassava starch (from 426.61 to 670.11 relative viscosity units (RVU)) and jicama starch (from 160.17 to 561.50 RVU) but decreased that of potato starch (from 669.44 to 206.92 RVU). When carbonyl and carboxyl groups were incorporated into jicama starch granules, the resistance of these granules to stirring at constant temperature (holding) increased, as did their final and retrogradation viscosities. However, the behaviour of oxidised cassava and potato starches, as indicated by a Rapid Visco Analyser, was different. The highest values of endotherm enlargement were found for native and oxidised jicama starch, while the lowest values were found for native and oxidised cassava starch. Native and oxidised potato starch had the highest enthalpy values (14.30–18.30 J g−1), while jicama starch had the lowest (9.50–11.9 J g−1). The high intrinsic viscosity of native potato starch was attributed to B‐type starch with a longer‐than‐average amylopectin chain length and a lower degree of crystallinity. Oxidised granules showed little erosion in the form of grooves; on the contrary, oxidation left the grains with a very smooth surface. Copyright © 2007 Society of Chemical Industry
Diminution of quinolizidine alkaloids, oligosaccharides and phenolic compounds from two species of Lupinus and soybean seeds by the effect of Rhizopus oligosporus
Authors: Jiménez‐Martínez Cristian , Hernández‐Sánchez Humberto , Dávila‐Ortiz Gloria
Published: April 2007

Lupinus, like Glycine max (soybean), is an ancient leguminous plant. It has been used as a food by people living around the Mediterranean Sea and in the Andean Highlands. This legume contains quinolizidine alkaloids (Qas), oligosaccharides (OGS) and phenolic compounds (PC). The objective of this study was to evaluate the effect of the growth of Rhizopus oligosporus on the levels of Qas, OGS and PC from L. mutabilis, L. campestris and G. max through tempeh elaboration. The results showed that the soaking and cooking processes of legume seeds diminished the Qas content of L. mutabilis and L. campestris by 50%, and after 48 h of fermentation these compounds decreased by more than 90% in total. OGS diminished by more than 90% in the lupin seeds. The PC content of the three seed species subjected to these processes increased their absorbance value, probably due to the enzymatic action of a fungal tannase. These results suggested that the L. mutabilis, L. campestris and G. max fermentation with R. oligosporus is an efficient method for diminishing antinutritional factors and for obtaining a product with optimal nutritional value. Copyright © 2007 Society of Chemical Industry
Phosphorus characterization in feces from broiler chicks fed low‐phytate barley diets
Authors: Leytem April B , Thacker Phil A , Turner Benjamin L
Published: April 2007

The inclusion of low phytate grains in poultry diets can reduce the phosphorus (P) content of poultry feces, but their influence on fecal P composition is not well established. To assess this, 100 male broiler chicks (21 days old) were fed dietary treatments based on either a wild‐type barley or one of three low phytate mutant barleys with 59, 62 and 99% reductions in phytate P, compared with the normal barley diet. The birds were housed in raised‐floor battery cages with mesh grate floors above fecal collection trays with five birds per pen and five pens per treatment. The birds were fed for 9 days and feces were collected twice a day during the last 2 days of the experiment. Total P concentrations were 14–24% lower in feces from birds fed low phytate barley diets compared with those fed the normal barley diet. Phosphorus digestibility increased (P < 0.05) as phytate in the barley diet decreased. Phosphate was the major P fraction in the feces (69–75% extracted P) regardless of the type of barley fed. Phytate constituted only 3–12% of the P in the feces, indicating its hydrolysis in the bird. Overall, these results suggest that feeding low‐phytate barley diets can reduce P concentrations in poultry feces without causing significant changes in P composition. Copyright © 2007 Society of Chemical Industry
Brachypodium: a new monocot model plant system emerges
Authors: Garvin David F
Published: April 2007

The small grass species Brachypodium distachyon (purple false brome) is potentially an ideal model plant system for grass crop research. To realise this potential, a range of genetic and genomic resources have been developed in a very short period of time, and more still are in the pipeline. David Garvin explains how these resources will establish B. distachyon as the newest model plant system and will fill a long‐empty void in genomics resources for grass crop improvement. Copyright © 2007 Society of Chemical Industry
Flavour and aroma of fresh basil are affected by temperature
Authors: Chang Xianmin , Alderson Peter G , Hollowood Tracey A , Hewson Louise , Wright Carles J
Published: April 2007

Sweet basil (Ocimum basilicum L.) plants at the three‐leaf‐pair growth stage were grown in controlled environment rooms at 15 and 25 °C for 2 weeks. Analysis of volatiles from blended leaves by gas chromatography/mass spectrometry showed that the plants grown at 25 °C contained significantly more volatile oils than those grown at 15 °C. The total volatile oil content in fresh leaves was enhanced by 70%. Temperature also affected the composition of volatile oils. At 25 °C there was an accumulation of eugenol, which contributes to the characteristic taste of basil. Although there was no effect on the relative contents of linalool and 1,8‐cineole, the absolute contents in fresh leaves were significantly different. Sensory analysis showed that 18 out of 21 trained sensory panellists perceived different intensities of volatile oils in fresh basil leaves from the two sources of plants. In addition, a simple consumer preference test conducted with basil users showed a significant preference for the stronger intensity (41 out of 64 consumers). Copyright © 2007 Society of Chemical Industry
Nutritional value of diets containing graded levels of wheat distillers grains with solubles fed to broiler chicks
Authors: Thacker Philip A , Widyaratne Gemunu P
Published: April 2007

This feeding trial was conducted to determine the effects of graded levels of wheat distillers dried grains with solubles (DDGS) on nutrient digestibility and performance when fed to broiler chicks. A total of 125, day‐old, male broiler chicks (52.8 ± 0.6 g) were fed wheat/soybean meal‐based diets containing 0, 5, 10, 15 or 20% wheat DDGS. There were five birds per pen and five replicate pens per treatment. Digestibility coefficients for dry matter (P = 0.001), energy (P = 0.001) and phosphorus (P = 0.001) declined in a linear manner with increasing levels of wheat DDGS in the diet. Despite the lower digestibility of nutrients in diets containing wheat DDGS, there were no significant differences in weight gain (P = 0.721), feed intake (P = 0.748) or feed conversion (P = 0.766) due to the incorporation of wheat DDGS in the diet, although weight gain and feed conversion showed a tendency to decline at the highest inclusion level (20%) in the diet. The overall results of this study indicate that wheat DDGS can be successfully incorporated into diets fed to broiler chicks. Potential detrimental factors contained in wheat DDGS, including a low energy and low lysine content, can be compensated for in diet formulation. Therefore, when the price of alternative feed ingredients dictates, wheat DDGS can be incorporated into diets at levels as high as 15% without detrimental effects on broiler performance. Copyright © 2007 Society of Chemical Industry
Preparative isolation and purification of flavone compounds from Sophora japonica L. by high‐speed counter‐current chromatography combined with macroporous resin column separation
Authors: Sun Ailing , Sun Qinghua , Liu Renmin
Published: April 2007

High‐speed counter‐current chromatography combined with macroporous resin column separation was applied to the isolation and purification of genistein‐7,4′‐di‐O‐β‐D‐glucoside (I), genistein‐7‐O‐β‐D‐glucopyranoside‐4′‐O‐[(α‐L‐rhamnopyransoyl)‐(1‐2)‐β‐D‐glucopyranoside] (II), kaempferol‐3‐O‐β‐D‐sophoroside(III), quercetin‐3‐O‐β‐L‐ramnopyranosyl‐(1–6)‐β‐D‐glucopyranoside (IV), genistein‐4′‐β‐L‐rhamnopyransoyl‐(1–2)‐α‐D‐glucopyranoside (V), and kaempferol‐3‐O‐β‐L‐ramnopyranosyl‐(1–6)‐β‐D‐glucopyranoside (VI) from the Chinese medicinal herb Sophora japonica L. The crude extracts from the pericarps of Sophora japonica L. were pre‐separated on a D‐101 macroporous resin column and divided into two parts as sample 1 and sample 2. An 80‐mg portion of sample 1 was separated by using n‐butanol‐acetic acid (1%) (5:5, v/v) as the two‐phase solvent system and yielded 30.1 mg of compound I, 23.3 mg of compound II. A 120‐mg portion of sample 2 was separated by using ethyl acetate‐n‐butanol‐acetic acid (1%) (5:0.8:5, v/v) as the two‐phase solvent system and yielded 5.5 mg of compound III, 31.7 mg of compound IV, 37.4 mg of compound V, and 6.2 mg of compound VI. The purities of compounds I, II, III, IV, V, and VI were 98.7, 98.2, 97.8, 98.5, 99.3, and 98.9%, respectively, as determined by HPLC. The chemical structures of these components were identified by 1H‐NMR and 13C‐NMR.
Potential sources of background contaminants in solid phase extraction and microextraction
Authors: Stiles Robert , Yang Ill , Lippincott Robert Lee , Murphy Eileen , Buckley Brian
Published: April 2007

A study to identify the sources of background contamination from SPE, using a C‐18 sorbent, and solid‐phase microextraction (SPME), using a 70 μm carbowax/divinylbenzene (CW/DVB) fiber, was carried out. To determine the source of contamination, each material used in the procedure was isolated and examined for their contribution. The solid‐phase column components examined were: sorbent material and frits, column housings and each solvent used to elute analytes off the column. The components examined in the SPME procedure were: SPME fiber, SPME vials, water (HPLC grade), and salt (sodium chloride) used to increase the ionic strength. The majority of the background contaminants from SPE were found to be from the SPE sorbent material and frits. The class of contaminants extracted during a blank extraction were phthalates and other plasticizers used during the manufacturing process. All had blank levels corresponding to measured concentrations below 2 ng/mL, except for undecane, which had a concentration of 5.4 ng/mL. The most prevalent contaminants in the SPME blank procedure are 1,9‐nonanediol, a mixture of phthalates and highly bis‐substituted phenols. All the concentrations were below 2 ng/mL, with the exception of bis (2‐ethylhexyl) phthalate, which had concentrations ranging from 5 to 20 ng/mL.
Miniaturized asymmetrical flow field‐flow fractionation: Application to biological vesicles
Authors: Oh Sunok , Kang Dukjin , Ahn Sung‐Min , Simpson Richard J. , Lee Bong‐Hee , Moon Myeong Hee
Published: April 2007

Asymmetrical flow field‐flow fractionation (AFlFFF) has been carried out in a miniaturized channel by reducing the channel dimensions. Performance of the miniaturized AFlFFF (mAFlFFF) channel was evaluated with standard proteins and polystyrene latex spheres from nanometer to micrometer size. By reducing the channel dimension, proteins or particulate materials can be separated within a few minutes without a significant loss in resolution. The mAFlFFF channel was applied for the separation of exosomes harvested from immortalized human mesenchymal stem cell line. It shows a potential to fractionate exosome vesicles according to sizes which can be useful for proteomic studies in relation to immunotherapeutic applications.
Determination of (E)‐10‐hydroxy‐2‐decenoic acid content in pure royal jelly: A comparison between a new CZE method and HPLC
Authors: Ferioli Federico , Marcazzan Gian Luigi , Caboni Maria Fiorenza
Published: April 2007

A new CZE method was developed and compared with HPLC for the determination of (E)‐10‐hydroxy‐2‐decenoic acid (10‐HDA) in royal jelly (RJ) samples of different geographical origin. The results obtained with the CZE method were highly correlated with those of HPLC (p <0.01). Under optimized conditions, CZE employed minimal amounts of 50 mM tetraborate buffer as BGE, without the addition of organic solvents, EOF or pH modifiers. The CZE method showed a wide linear response range (0.006–0.808 mg 10‐HDA/mL), a good sensitivity (LOD and LOQ were 0.002 and 0.004 mg/mL, respectively) and a satisfactory instrumental repeatability with respect to migration time and peak area (RSD% less than 1.0 and 2.0% on migration time for intra‐ and interday assay, respectively and less than 2.0 and for 4.0% on peak area for intra‐ and interday assay, respectively). The 10‐HDA content in RJ ranged from 0.8 to 3.2 g/100 g of RJ and a significant difference (p <0.05) was found between the Italian and extra‐European average values: 2.5 and 1.6 g/100 g of RJ, respectively, according to the CZE data. The possibility of application of CZE for routine analyses on RJ and RJ based products to verify their authenticity is highlighted here.
Preparation and chiral recognition ability of crosslinked beads of polysaccharide derivatives
Authors: Ikai Tomoyuki , Yamamoto Chiyo , Kamigaito Masami , Okamoto Yoshio
Published: April 2007

The spherical beads consisting of cellulose 3,5‐dimethylphenylcarbamate with partial hydroxyl groups were prepared to be used as chiral packing materials (CPMs) for HPLC. The beads were obtained without using macroporous silica gel, which is usually used as the support of the CPMs based on the polysaccharide derivatives. After the crosslinking in the bead with diisocyanates, such as 4,4′‐diphenylmethane diisocyanate (MDI), 4,4′‐dibenzyl diisocyanate (DBDI), tolylene‐2,4‐diisocyanate (TDI), and m‐xylylene diisocyanate (XDI), the obtained beads were packed into an HPLC column. As the content of the hydroxyl groups of the cellulose derivatives decreased, the obtained CPM exhibited a higher chiral recognition ability. The beads possessed a higher loading capacity than the CPM prepared by coating the cellulose derivative on silica gel. The crosslinked beads could be used with the eluent containing chloroform. The amylose derivative beads were also prepared as a CPM for chiral HPLC.
Quality of parental relationships among persons with a lifetime history of posttraumatic stress disorder
Authors: Lauterbach Dean , Bak Christina , Reiland Sarah , Mason Shawn , Lute Michael R. , Earls Lauren
Published: April 2007

Several studies of combat veterans have examined the relationship between parental satisfaction and PTSD symptoms. These studies found that numbing is associated with substantial decrements in parent–child relationship quality. The current study extends previous work by assessing the effect of PTSD on parent–child relationships in a nationally representative sample of civilian men and women with PTSD resulting from a broad range of trauma. It was hypothesized that PTSD avoidance/numbing symptoms would be predictive of parent–child relationship quality and parent–child conflict. Moreover, these relationships are predicted to hold after controlling for a broad range of support‐related variables and work/finance related variables. As hypothesized, after controlling for number of children and respondent‐initiated domestic violence, numbing was predictive of increased parent–child aggression.
Confirmatory factor analysis of posttraumatic stress symptoms in cambodian refugees
Authors: Palmieri Patrick A. , Marshall Grant N. , Schell Terry L.
Published: April 2007

This study used confirmatory factor analysis to examine the factor structure of the Cambodian version of the Harvard Trauma Questionnaire in 488 Cambodian refugees residing in the United States. Five alternative conceptual models were compared. A model with four correlated factors reflecting symptoms of reexperiencing, avoidance, emotional numbing, and hyperarousal provided the best fit to these data. The avoidance and emotional numbing clusters demonstrated distinct associations with depression symptoms, providing some evidence of the construct validity of the four‐factor solution.
Intrusive memories and ruminations related to violent crime among young offenders: Phenomenological characteristics
Authors: Evans Ceri , Ehlers Anke , Mezey Gillian , Clark David M.
Published: April 2007

Very little is known about the nature of perpetrator's memories of violent crime. The authors conducted semistructured interviews with a representative sample of 105 young offenders convicted of serious violence, assessing intrusive memories, ruminations, and symptoms of posttraumatic stress disorder related to their violent crime. Forty‐eight (46%) participants described significant intrusive memories of the assault, and 38 (36%) reported ruminations related to the assault. Ethnic origin and historical variables explained 19% of the variance of posttraumatic stress disorder symptom severity; intrusion and rumination characteristics added an additional 48% explained variance. The intrusive memories tended to concern the moment when the event turned for the worse for the perpetrator. The findings have implications for risk assessment and therapeutic interventions for violent offenders.
The criterion a problem revisited: Controversies and challenges in defining and measuring psychological trauma
Authors: Weathers Frank W. , Keane Terence M.
Published: April 2007

The Criterion A problem in the field of traumatic stress refers to the stressor criterion for posttraumatic stress disorder (PTSD) and involves a number of fundamental issues regarding the definition and measurement of psychological trauma. These issues first emerged with the introduction of PTSD as a diagnostic category in the Diagnostic and Statistical Manual of Mental Disorders, Third Edition (DSM‐III; American Psychiatric Association, 1980) and continue to generate considerable controversy. In this article, the authors provide an update on the Criterion A problem, with particular emphasis on the evolution of the DSM definition of the stressor criterion and the ongoing debate regarding broad versus narrow conceptualizations of traumatic events.
A c-cut Nd:GdVO4 solid-state laser passively Q-switched with Co2+:LaMgAl11O19 lasing at 1.34 μm
Authors: Qi H-J , Liu X-D , Hou X-Y , Li Y-F , Sun Y-M
Published: April 2007

We investigated a high power diode-laser pumped passively Q-switched c-cut Nd:GdVO4 solid-state laser, lasing at 1.34 μm, with a Co2+:LaMgAl11O19 saturable absorber. With the optimum output coupler transmission T=5.5% and pump power of 11.5 W, the static output power of 3.01 W was obtained. The passively Q-switching operation with Co:LMA (initial transmission T
0=90%) as saturable absorber, shows that the shortest output pulse width, the highest output power, the highest pulse repetition and the highest pulse peak power were 32 ns, 266 mW, 277 kHz, and 187 W, respectively.
1 MHz repetition rate single-frequency gain-switched Nd:YAG microchip laser
Authors: Wang Y , Huang L , Gong M , Zhang H , Lei M , He F
Published: April 2007

Gain-switched Nd:YAG microchip lasers have produced 1 MHz repetition rate, single-frequency pulses with a pulse width of 32 ns. This is, to our knowledge, the highest repetition rate obtained in a single-frequency gain-switched solid state laser. The laser peak power and pulse width are mainly determined by the peak power of the pumping pulse and independent of the pulse repetition rate. Single-frequency operation is realized by temperature-tuning of the laser wavelength to the peak of the gain profile. Gain-switching at high repetition rates significantly improves the optical efficiency of the device.
Multiwavelength Brillouin/Erbium-Ytterbium fiber laser
Authors: Harun S W , Emami S D , Abd Rahman F , Muhd-Yassin S Z , Abd-Rahman M K , Ahmad H
Published: April 2007

A multi-wavelength Brillouin/Erbium-Ytterbium doped fiber laser which operates in the 1535 nm region is proposed and demonstrated. The system employs both linear and nonlinear gain from a 4 meter Erbium-Ytterbium doped fiber and an 8 km single mode fiber respectively to generate an optical comb with a spacing of approximately 0.084 nm. A stable output laser comb of more than 22 lines was obtained with a Brillouin pump of 2 dBm and a 1058 nm pump of 175 mW. A maximum peak power of -4.2 dBm was obtained at a wavelength of 1535.16 nm at these pump power settings while the spectral linewidth of the laser is approximately 8 Hz.
Hydration Characterization of Hydrophobically Modified Polymers by Dielectric Measurements in the Millimeter Range
Authors: Vorob'ev Mikhail , Churochkina Natalia , Khokhlov Alexei , Stepnova Evgenia
Published: April 2007

Bound water molecules, the fraction of water molecules that are present in the hydration shells of polymers, lose their rotational mobility in the time scale of 10–50 ps, leading to additional ordering compared with unperturbed water. The amount of bound water per number of carbons in the nonpolar groups as measured by the method of waveguide dielectric resonance increased in the following order: hydrophobically modified chitosan < globular protein < hydrophobically modified polyacrylamide. The hydrophobic modification of acrylamide and chitosan polymers gave smaller variation in hydration than did both the coil‐to‐globule transition of poly(N‐isopropylacrylamide) and the masking of nonpolar groups within the protein globule.

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Efficient Modification on PLLA by Ozone Treatment for Biomedical Applications
Authors: Ho Ming‐Hua , Lee Juin‐Jay , Fan Shu‐Chin , Wang Da‐Ming , Hou Lein‐Tuan , Hsieh Hsyue‐Jen , Lai Juin‐Yih
Published: April 2007

RGDS (Arg‐Gly‐Asp‐Ser) is immobilized on poly(L‐lactic acid) (PLLA) with ozone oxidation and the addition of an intermediate reactant, acryl succinimide (ASI) to promote the grafting efficiency. A DPPH (2,2‐di(4‐tert‐octylphenyl)‐1‐picrylhydrazyl) assay has revealed that the peroxide concentration can be controlled by adjusting the ozone treatment time. The immobilization of ASI is verified by elemental analysis. The peptide concentrations are in the effective order, as shown by means of high performance liquid chromatography (HPLC), and the grafting efficiency is proven to be relatively high compared with the previous studies. The culture of rat osteosarcoma 17/2.8 (ROS), osteoblastic‐like cells, demonstrates that the grafting of RGDS can enhance the attachment and osteogenesis of ROS cells on PLLA. With the addition of ASI, the cultured ROS cells express normal function in proliferation and mineralization. From in vivo experiments, ASI immobilized on the surface is shown to be biocompatible. These results lead to the conclusion that the ozone treatment with the intermediate reactant ASI is an efficient, biocompatible, and easily controllable procedure to modify PLLA. Furthermore, the immobilization of RGDS in significant amounts following the ozone oxidation could further promote the biocompatibility and the osteoinduction of PLLA.

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Cell Migration Rate on Poly(ε‐caprolactone)/Poly(ethylene glycol) Diblock Copolymers and Correlation with the Material Sliding Angle
Authors: Hsu Shan‐hui , Tang Cheng‐Ming , Chiu Jeng‐Jiann , Liao Tien‐Chi , Lin Chu‐Chieh , Iwata Hiroo
Published: April 2007

The nanostructure of a biomaterial surface has strong influence on cell behavior. The migration of cells on nanostructured surfaces, however, has not been investigated so far. In this study, we used PCL/PEG diblock copolymers as model surfaces to examine the effect of nanoislands on migration of different cells, including fibroblasts and endothelial cells. The water sliding angle of the substrates was measured. The cell migration rate was examined under a real‐time optical microscope. It was found that a greater cell migration rate correlated with the smaller sliding angle of the substrate.

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Homogeneous Tritylation of Cellulose in 1‐Butyl‐3‐methylimidazolium Chloride
Authors: Erdmenger Tina , Haensch Claudia , Hoogenboom Richard , Schubert Ulrich S.
Published: April 2007

1‐Alkyl‐3‐methylimidazolium‐based ionic liquids, having chloride as a counter ion, were studied for cellulose solubility; and the influence of different alkyl chain lengths was also investigated. The alkyl chain length was incrementally varied from ethyl to decyl to determine structure‐dissolution properties; a distinct odd‐even effect was observed for short chain lengths. In addition, the tritylation of cellulose was performed in 1‐butyl‐3‐methylimidazolium chloride using pyridine as base. The influences of reaction time and the ratio of trityl chloride per cellulose monomer unit on the degree of substitution were investigated in detail by elemental analysis and 1H NMR spectroscopy. A DS of around 1 was obtained after 3 h reaction time using a six fold excess of trityl chloride.

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In Vivo Evaluation of a Biodegradable EDC/NHS‐Cross‐Linked Gelatin Peripheral Nerve Guide Conduit Material
Authors: Chang Ju‐Ying , Lin Jia‐Horng , Yao Chun‐Hsu , Chen Jiunn‐Horng , Lai Tung‐Yuan , Chen Yueh‐Sheng
Published: April 2007

Peripheral nerve regeneration has been evaluated using a biodegradable nerve conduit, which is made of a 1‐ethyl‐3‐(3‐dimethylaminopropyl)carbodiimide (EDC)/N‐hydroxysuccinimide (NHS) cross‐linked gelatin. The EDC/NHS crosslinked gelatin (ENG) conduit is brownish in appearance, and is concentric and round with a smooth outer surface and inner lumen. After subcutaneous implantation on the dorsal side of a rat, the degraded ENG conduit only evoked a mild tissue response, with the formation of a thin tissue capsule surrounding the conduit. Biodegradability of the ENG conduit and its effectiveness as a guidance channel has been examined by its use to repair a 10 mm gap in the rat sciatic nerve. As a result, the tubes degraded throughout the implantation period, but still remained circular with a thin round lumen until they were completely integrated with the enclosed nerves. Successful regeneration through the gap occurred in all the conduits over the three experimental periods of 4, 8, and 12 weeks. Histological observation showed that numerous myelinated axons had crossed through the gap region even at the shortest implantation period of 4 weeks. Peak amplitude, area under the muscle action potential curve, and nerve conductive velocity all showed an increase as a function of the recovery period, which indicates that the nerve had undergone adequate regeneration. These results indicate the superiority of the ENG materials and suggest that the novel ENG conduits provide a promising tool for neuro‐regeneration.

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Synthesis and Characterization of Degradable p(HEMA) Microgels: Use of Acid‐Labile Crosslinkers
Authors: Bulmus Volga , Chan Yannie , Nguyen Quyen , Tran Hong L.
Published: April 2007

New divinyl‐functionalized acetal‐based crosslinkers were synthesized as building elements to form acid‐labile microgel particles for controlled‐release applications. The synthesized crosslinkers underwent hydrolysis at slightly acidic pHs in less than 1 h while they were stable at neutral pHs for longer times. HEMA was copolymerized with the crosslinkers via an inverse emulsion polymerization technique using a redox initiator system at room temperature to form crosslinked, colloidal p(HEMA) microgels. Microgels in diameters ranging from 150 to 475 nm with narrow distribution could be produced. The crosslinking density and the diameter of the microgels were found to be controlled by monomer/crosslinker feed ratio. The microgels demonstrated a pH‐dependent cleavage behavior that mimicked the pH‐dependent hydrolysis profile of the acid‐labile crosslinkers. Model biomacromolecules, i.e., Rhodamine B‐labeled dextran and BSA were efficiently loaded into the microgels. The release of the biomolecules from p(HEMA) microgels was also found to be controllable by the pH of the environment similar to the particle degradation. The protein released from the microgels was observed to retain its structural stability.

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