bluuebunny/crossref_metadata_2025_split huggingface dataset:
Electronic structure analyses of BN network materials using high energy‐resolution spectroscopy methods based on transmission electron microscopy
Authors: Terauchi M. 
Published: May 2006

AbstractElectronic structures of boron‐nitride (BN) nanotubes and a BN cone‐structure material were studied by using a high energy‐resolution electron energy‐loss spectroscopy (EELS) microscope. A trial of the whole electronic structure study of hexagonal BN (h‐BN), which consists of flat BN honeycomb layers, was conducted by a combination of EELS and X‐ray emission spectroscopy (XES) based on transmission electron microscopy (TEM) (TEM‐EELS/XES). The π and π+σ plasmon energies of BN nanotubes (BNT) were smaller than those of h‐BN. The π+σ energy was explained by the surface plasmon excitation. The spectrum of a two‐wall BNT of 2.7 nm in diameter showed a new spectral onset at 4 eV. The valence electron excitation spectra obtained from the tip region of the BN cone with an apex angle of 20° showed similar intensity distribution with those of BNTs. The B K‐shell electron excitation spectra obtained from the bottom edge region of the BN cone showed additional peak intensity when compared with those of h‐BN and BNT. The B K‐shell electron excitation spectra and B K‐emission spectra of h‐BN were compared with a result of a LDA band calculation. It showed that high symmetry points in the band diagram appear as peak and/or shoulder structures in the EELS and XES spectra. Interband transitions appeared in the imaginary part of the dielectric function of h‐BN experimentally obtained were assigned in the band diagram. The analysis also presented that the LDA calculation estimated the bandgap energy smaller than the real material by an amount of 2 eV. Those results of TEM‐EELS/XES analysis presented that high energy‐resolution spectroscopy methods combined with TEM is a promising method to analyze whole electronic structures of nanometer scale materials. Microsc. Res. Tech., 2006. © 2006 Wiley‐Liss, Inc.
Determination of the propylene oxide–hemoglobin adduct by gas chromatography‐electron impact ionization mass spectrometry
Authors: Shin Ho‐Sang , Ahn Hye‐Sil 
Published: May 2006

AbstractA gas chromatography‐mass spectrometry method was developed for the determination of the propylene oxide (PO)–hemoglobin adduct. The adduct was identified as hydroxy propyl valine (HPV), and released from globin by the modified Edman degradation and extracted with ethyl ether. HPV and deuterated HPV (d6‐HPV) were synthesized for identification and quality control. d6‐HPV was used as an internal reference standard. The dried extract was completely derivatized with N‐methyl‐N‐(trimethylsilyl) trifluoroacetamide (MSTFA). The method detection limit (MDL) of the assay was 10 pmole/g for HPV, based on assayed hemoglobin of 0.1 g. The method was applied to the determination of the PO–hemoglobin adduct formed in young female Sprague–Dawley rats after treatment for 4 and 5 weeks with 5 and 10 mM PO via drinking water. HPV was detected by the proposed procedure. After 4 weeks, the concentration of HPV was 6.75 nmole/g hemoglobin during treatment with 5 mM, and 80.26 nmole/g hemoglobin during treatment with 10 mM. The adduct level in 5 weeks increased up to about 51.47 nmole/g during treatment with 5 mM PO in the drinking water and up to about 120.27 nmole/g during treatment with 10 mM PO. This method was also applied to determine the concentrations of HPV in the blood of 20 persons living near the Ulsan petroleum industrial complex in Korea. As a result, HPV‐hemoglobin adduct was detected in the concentration range 0–1100 pmol/g in the human blood samples. Copyright © 2006 John Wiley & Sons, Ltd.
Determination of polycyclic aromatic hydrocarbons in olive oil by a completely automated headspace technique coupled to gas chromatography‐mass spectrometry
Authors: Arrebola Francisco J. , Frenich A. Garrido , González Rodríguez Manuel J. , Bolaños Patricia Plaza , Martínez Vidal José L. 
Published: May 2006

AbstractA new and completely automated method for the determination of ten relevant polycyclic aromatic hydrocarbons (PAHs) in olive oil is proposed using an extraction by the headspace (HS) technique. Quantification and confirmation steps are carried out by gas chromatography‐mass spectrometry (GC‐MS) combining simultaneously selected‐ion monitoring (SIM) and tandem mass spectrometry (MS/MS). This combination offers on one hand an increased sensitivity and on the other hand, selective and reliable qualitative information. Sample pretreatment or clean‐up are not necessary because the olive oil sample is put directly into an HS vial, automatically processed by HS and introduced into the GC‐MS instrument for analysis. Because of its high selectivity and sensitivity, a triple‐quadrupole (QqQ) detector coupled with the gas chromatograph allows us to limit handling. Each sample is completely processed in approximately 63 min (45 min for HS isolation and 18 min for GC‐MS determination), a reduced time compared with previously published methods. The chemical and instrumental variables were preliminarily optimized using uncontaminated olive oil samples spiked with 25 µg kg−1 of each target compound. The final method was validated to ensure the quality of the results. The precision was satisfactory, with relative standard deviation (RSD) values in the range 3–9%. Recovery rates ranged from 96 to 99%. Limits of detection (LOD) were calculated as 0.02–0.06 µg kg−1 and the limits of quantification (LOQ) were obtained as 0.07–0.26 µg kg−1. It must be mentioned that the LOD and LOQ are much lower than the maximum levels established by the European Union (EU) in oils and fats intended for direct human consumption or for use as an ingredient in foods, which are set at 2 µg kg−1. All the figures of merit are completely in accordance with the latest EU legislation. This fact makes it possible to consider the proposed method as a useful tool for the control of PAHs in olive oils. Copyright © 2006 John Wiley & Sons, Ltd.
Combining ability and heritability for vitamin C and total soluble solids in pepper (Capsicum annuum L.)
Authors: Geleta Legesse F , Labuschagne Maryke T 
Published: May 2006

AbstractTwenty‐one F1 hybrids and seven parental genotypes were used to assess combining ability and heritability for vitamin C and total soluble solids in pepper (Capsicum annuum L.). The mean squares for general (GCA) and specific (SCA) combining abilities were highly significant for the two traits, suggesting the importance of both additive and non‐additive gene effects. However, additive gene action was more important, as GCA estimates were much higher than SCA effects. Among the parental genotypes, ‘Mareko Shote’ and ‘PBC 142A’, and ‘PBC 142A’ were good general combiners for vitamin C and total soluble solids, respectively, and could be used to improve these traits in pepper breeding programmes for the accumulation of favourable genes. They also showed the highest per se performance (315.3 mg 100 g−1 and 18.5 Brix, respectively) for the two quality traits. The narrow sense heritability estimate for vitamin C was relatively high (54.8%) indicating that the environment had a less pronounced effect on this trait. The heritability for total soluble solids was low (15%). Copyright © 2006 Society of Chemical Industry
Occurrence of acetic acid and formic acid in breakfast cereals
Authors: Rufián‐Henares José A , Delgado‐Andrade Cristina , Morales Francisco J 
Published: May 2006

AbstractBreakfast cereals are usually manufactured by extrusion followed by drying and toasting steps in which thermal treatments are applied. In addition, owing to the low water activity and the content in cereals of proteins and carbohydrates, precursors of the Maillard reaction, this reaction and degradation of sugars are favoured during processing. Acetic and formic acids have been identified as final products of Maillard reaction (MR) and sugar caramelisation. Acetic and formic acid contents have been determined by ion exchange high‐performance liquid chromatography in 56 commercial breakfast cereals. Results were evaluated taking into account the sample formulation. Acetic and formic acids were detected in all samples, and significant variations were observed for acetic acid depending on the protein and fibre content. Acetic acid, originating from 1‐deoxyglucosone cleavage during MR, proved to be a good indicator of processing in cereals enriched with or based on wheat flour because of their high protein content. Fibre addition increased acetic acid concentration. The application of acetic acid as a chemical marker of processing in breakfast cereals and its possible generation pathways are discussed. Copyright © 2006 Society of Chemical Industry
Inactivation kinetics of pectin methylesterase in orange juice as a function of pH and temperature/time process conditions
Authors: Tribess Tatiana B , Tadini Carmen C 
Published: May 2006

AbstractPasteurisation of orange juice (OJ) is necessary to prevent spoilage due to microorganisms and enzymes, mainly pectin methylesterase (PME). PME has a higher thermal resistance than the bacteria and yeasts existing in OJ and therefore its inactivation is used as a parameter to define the time/temperature combination of the thermal process. The enzyme has isoforms with different activities and thermal resistances. A three‐parameter model can be used to describe the kinetics of PME inactivation, where the more and less thermally resistant fractions are represented. In this study the thermal inactivation kinetics was evaluated at six pH values (3.6, 3.7, 3.8, 3.9, 4.0 and 4.1), three minimal temperatures (82.5, 85.0 and 87.5 °C) and at least six holding times for each condition. It was found that the thermolabile PME fraction (a) was influenced by pH and processing temperature. A slower reaction rate constant (k1) was found for juices with pH values of 3.8 and 3.9 at the studied temperatures. The highest inactivation levels were obtained in juices with pH values of 3.6 and 3.7. Copyright © 2006 Society of Chemical Industry
Effect of garlic powder on the performance, egg traits and blood parameters of laying hens
Authors: Yalçın Sakine , Onbaşılar E Ebru , Reisli Zehra , Yalçın Suzan 
Published: May 2006

AbstractThis study was conducted to investigate the effects of garlic powder on the performance, egg traits and blood parameters of laying hens. One hundred and sixty‐two SHSY‐type brown layers aged 21 weeks were chosen at random from a large flock. They were allocated to three dietary treatments. Each treatment comprised six replicates of nine layers in groups of three. The diets were supplemented with 0, 5 and 10 g kg−1 garlic powder. The experimental period lasted 22 weeks. Garlic powder addition did not significantly affect body weight, egg production, feed consumption, feed efficiency, egg shell index, egg breaking strength, egg shell thickness, egg albumen index, egg yolk index, egg Haugh unit, egg yolk weight and serum protein concentration. Egg weight increased (P < 0.01) with garlic powder supplementation. There was a significant (P < 0.01) reduction in egg cholesterol concentration as mg g−1 yolk when the dietary level of garlic powder was increased from 0 to 10 g kg−1. Hen serum triglyceride (P < 0.05) and total cholesterol (P < 0.01) concentrations decreased with garlic powder supplementation. This study demonstrated that garlic powder addition increased egg weight and decreased egg yolk cholesterol concentration (mg g−1 yolk) and serum triglyceride and cholesterol concentrations without adverse effects on performance and egg traits. Copyright © 2006 Society of Chemical Industry
A systematic approach for extraction of phenolic compounds using parsley (Petroselinum crispum) flakes as a model substrate
Authors: Luthria Devanand L , Mukhopadhyay Sudarsan , Kwansa Albert L 
Published: May 2006

AbstractThe impact of extraction methodology and polarity of extraction solvents on the assay of phenolic compounds was investigated using parsley (Petroselinum crispum) flakes as a model substrate. This systematic study was undertaken to address substantial variations in the extraction procedures, solvents and conditions as described in the recent literature. Five different extraction procedures [shaking, vortex mixing, sonication, stirring and pressurized liquid extraction (PLE)] and three different solvents (methanol, ethanol and acetone), with five different solvent to water ratios per solvent, were used for extraction. Extracts were analyzed for phenolic content by high‐performance liquid chromatography and Folin–Ciocalteu assays. The yields of phenolic compounds extracted with a pressurized liquid extractor were comparable to or better than those of four classical extraction procedures. Optimum extraction efficiency with PLE was obtained when extractions were performed with four extraction cycles using ethanol–water (50:50, v/v). The amount of apiin (4,5,7‐trihydroxyflavone 7‐apiosylglucoside) and malonylapiin (apigenin malonylapiosylglucoside) isolated from parsley varied with the composition of extraction solvent. Apiin extractability was found to be a maximum when the solvent (ethanol, methanol or acetone) to water ratio was 30:70 (v/v), whereas higher amounts of malonylapiin were isolated with a reverse solvent to water ratio (70:30, v/v). Malonylapiin was not detected when parsley samples were extracted with organic solvent to water ratios of 10:90 (v/v) and 30:70 (v/v). Published in 2006 by John Wiley & Sons, Ltd
Synthesis of Substituted Polyacetylenes Grafted with Polystyrene Chains by the Macromonomer Method and Their Characterization
Authors: Zhang Wei , Shiotsuki Masashi , Masuda Toshio 
Published: May 2006

AbstractSummary: A macromonomer (1) consisting of a polystyrene chain and an acetylenic chain end ($\overline M _{\rm n}$ = 2 500, $\overline M _{\rm w} /\overline M _{\rm n}$ = 1.20) was prepared by atom transfer radical polymerization. Macromonomer 1 was copolymerized with phenylacetylene (2) and propargyl 2‐bromopropionate (3) by using Rh catalysts at varying feed ratios from 10 to 50 wt.‐% to produce graft copolymers 4 and 5, respectively. The synthesized copolymers 4 and 5 possessed a conjugated polyene main‐chain and polystyrene grafts, and contained 11–34 and 16–77 wt.‐% of polystyrene with $\overline M _{\rm n}$ of 61 400–144 000 and 19 300–22 500, respectively. Graft copolymer 4 was a yellow solid and thermally stable up to 225 °C, whereas 5 was a brown solid with weight loss beginning at 175 °C. Graft copolymers 4 and 5 exhibited UV‐vis absorption edges at 525 and 425 nm, respectively, which are attributable to the conjugated main‐chain structure.Copolymerization of the acetylene‐terminated polystyrene‐based macromonomer with monosubstituted acetylenes.magnified imageCopolymerization of the acetylene‐terminated polystyrene‐based macromonomer with monosubstituted acetylenes.
Quantitative Analysis of Dielectric Constants from EFM Images of Multicomponent Polymer Blends
Authors: Krayev Andrey V. , Shandryuk Georgy A. , Grigorov Leonid N. , Talroze Raisa V. 
Published: May 2006

AbstractSummary: A simple quantitative model for the analysis of EFM images of three‐ or more‐component polymer blends is applied to determine the dielectric constants of the blend constituents. The value of the dielectric constant of PIPA calculated from the EFM images of POMA‐PIPA‐APP blend is determined in good agreement with the literature value.
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RAFT Polymerization of N‐Isopropylacrylamide and Acrylic Acid under γ‐Irradiation in Aqueous Media
Authors: Millard Pierre‐Eric , Barner Leonie , Stenzel Martina H. , Davis Thomas P. , Barner‐Kowollik Christopher , Müller Axel H. E. 
Published: May 2006

AbstractSummary: The ambient temperature (20 °C) reversible addition fragmentation chain transfer (RAFT) polymerization of N‐isopropylacrylamide (NIPAAm) and acrylic acid (AA) conducted directly in aqueous media under γ‐initiation (at dose rates of 30 Gy · h−1) proceeds in a controlled fashion (typically, $\overline M _{\rm w} /\overline M _{\rm n}$ < 1.2) to near quantitative conversions and up to number‐average molecular weights of 2.5 × 105 g · mol−1 for PNIPAAm and 1.1 × 105 g · mol−1 for PAA via two water‐soluble trithiocarbonate chain transfer agents, i.e., S,S‐bis(α,α′‐dimethyl‐α″‐acetic acid)trithiocarbonate (TRITT) and 3‐benzylsulfanylthiocarbonylsulfanyl propionic acid (BPATT). The generated polymers are successfully chain extended, which suggests that the RAFT agents are stable throughout the polymerization process so that complex and well‐defined architectures can be obtained.An increase of the monomer/CTA ratio leads to an increase of the molecular weight for the RAFT polymerization of NIPAAm under γ‐radiation in water using TRITT at ambient temperature.imageAn increase of the monomer/CTA ratio leads to an increase of the molecular weight for the RAFT polymerization of NIPAAm under γ‐radiation in water using TRITT at ambient temperature.
First Successful Post‐Synthetic Self‐Assembly of Polyaniline with Poly(N‐vinylpyrrolidone) into Aqueous Nanocolloids
Authors: Li Guorong , Li Bogeng 
Published: May 2006

AbstractSummary: Polyaniline (PANI) is successfully self‐assembled with poly(N‐vinylpyrrolidone) (PVP) into aqueous nanocolloids. The typical morphology of the colloids is studied by atomic force microscopy (AFM), which reveals spherical nanoparticles with a diameter of 80–150 nm. A possible mechanism for such a post‐synthetic self‐assembly process is proposed.AFM micrograph of PANI aqueous nanocolloids stabilized by PVP via a novel post‐synthetic self‐assembly method.imageAFM micrograph of PANI aqueous nanocolloids stabilized by PVP via a novel post‐synthetic self‐assembly method.
Amplification and diversity analysis of ketosynthase domains of putative polyketide synthase genes in Aspergillus ochraceus and Aspergillus carbonarius producers of ochratoxin A
Authors: Atoui Ali , Phong Dao Huy , Mathieu Florence , Lebrihi Ahmed 
Published: May 2006

AbstractThe diversity of polyketide synthase (PKS) genes in Aspergillus ochraceus NRRL 3174 and Aspergillus carbonarius 2Mu134 has been investigated using different primer pairs previously developed for the ketosynthase (KS) domain of fungal PKSs. Nine different KS domain sequences in A. ochraceus NRRL 3174 as well as five different KS domain sequences in A. carbonarius 2Mu134 have been identified. The identified KS fragments were distributed in five different clusters on the phylogenetic tree, indicating that they most probably represent PKSs responsible for different functions.
Sampling: the weak link in the sanitary quality control system of agricultural products
Authors: Blanc Michel 
Published: May 2006

AbstractTo ensure a high level of consumer protection, the European Union has in the past years published several regulations setting very low limits for a given number of food contaminants (pesticides, mycotoxins, heavy metals) in many agricultural products (cereals, oilseeds, dry fruits, coffee, spices, etc). These new regulations regarding the sanitary quality of agricultural products, compel both economic operators and officials of different EU member states to set up sampling plans and rigorous analyses aimed at checking whether a product lot complies with the required standards prior to its release on the market. While the laboratory analysis management today is outstanding thanks to the validated and efficient detection methods and procedures available for quality assurance in laboratories (accreditation), this is not necessarily true of the sampling operation, which seems to be the weak link in the sanitary control system for agricultural products. The sampling operation is often the main source of error when assessing the sanitary quality of a lot of agricultural commodities, with both commercial (downgrading of the product) and sanitary (marketing of a product which poses a health risk for the consumer) consequences. Therefore, it is essential for the operators involved to be aware of the significance and difficulties of the sampling operation, which requires important equipment and human resources. Furthermore, drawing up specific standards and guidelines, as well as setting up quality assurance procedures, at the level in charge of carrying out this delicate and important operation, are necessary.
Detection of small‐fiber neuropathy by sudomotor testing
Authors: Low Victoria A. , Sandroni Paola , Fealey Robert D. , Low Phillip A. 
Published: May 2006

AbstractThe symptoms of burning sensation affecting the feet, thought to be due to a distal small‐fiber neuropathy (DSFN) affecting somatic unmyelinated fibers, are usually accompanied by vasomotor or sudomotor changes suggestive of involvement of autonomic fibers. We therefore examined the relationship between pattern of anhidrosis and DSFN and its etiology, comparing patients with “pure” DSFN (with normal nerve conduction) to those with clinical DSFN (minor conduction abnormalities). We reviewed 125 cases with a clinical phenotype of DSFN. These patients had distal burning discomfort, variable sensory deficits, and intact motor function. All had undergone assessment with thermoregulatory sweat test (TST), autonomic reflex screen (ARS), and nerve conduction studies and electromyography (NCS/EMG). TST showed a distal pattern of anhidrosis in 74%. The quantitative sudomotor axon reflex test (QSART) was abnormal in 74%, with 80% of those having a length‐dependent pattern of anhidrosis/hypohidrosis. In total, 93% of patients had a distal pattern of abnormality on QSART or TST. The Composite Autonomic Severity Score (CASS) was used to quantify the severity and distribution of autonomic deficits: 98% had CASS abnormality (sudomotor, 98%; adrenergic, 43%; cardiovagal, 35%). EMG was normal or showed unrelated abnormalities in 75%. The most common etiologies of DSFN were idiopathic (73%), presumed hereditary (18%), and diabetes (10%). Sudomotor examination is thus a highly sensitive detection tool in DSFN. Autonomic involvement is mainly distal, and additionally may involve adrenergic and the long cardiovagal fibers. Muscle Nerve, 2006
Alterations in the gastrocnemius muscle of undernourished suckling rats
Authors: Silvado Carlos Eduardo , Werneck Lineu Cesar 
Published: May 2006

AbstractProtein‐energy undernutrition (PEU) during both the gestational and suckling periods causes a reduction in muscle fiber cross‐section and a delay in fiber type differentiation. Such changes are not found when PEU occurs after the suckling period. To elucidate the consequences of PEU on muscle during the suckling period, we undernourished (UND) newborn rats by reducing their food intake, including a 6‐hour fast every day, and doubling the number of pups suckled by the nursing rat. At day 24 of life, the gastrocnemius muscle showed a discrete reduction in lipids in the fibers of 5 control rats, and in 15 UND rats (P < 0.001). The type 2a and 2b fibers of the UND rats showed a smaller cross‐sectional area than control rats (P < 0.05). The distribution frequency histogram for the muscle fibers was skewed to the left in the undernourished rats, and this was significant for type 2a and 2b fibers. PEU during the suckling period may thus induce a delay in muscle fiber maturation but does not produce significant structural alterations. Muscle Nerve, 2006