bluuebunny/crossref_metadata_2025 huggingface dataset:
Challenges of Digital Education in India
Authors: Arvinth N.
Published: February 2024

During this pandemic situation across the world, the education system has completely changed. The internet and distant learning, which is commonly referred to as online instruction, are important components of the country's educational architecture. It is undeniable that online education provides sufficient benefits to young children. When all is said and done, there are numerous disadvantages to online education. The few disadvantages of online schooling are restricted cooperative learning, schedule expansion, and exertion. But considering the situation across the world we should move. Under consideration of problems discussing some suggestions for solving the problems caused. The main objective of this review is about electricity, network and conceptual understanding problems of students by digital education and how the system changed by this pandemic.
Effect of oxygen on nonthermal plasma reactions of nitrogen oxides in nitrogen
Authors: Zhao Gui‐Bing , Garikipati S. V. B. Janardhan , Hu Xudong , Argyle Morris D. , Radosz Maciej
Published: March 2005

NO is mainly converted to NO2 by chemical oxidation in the presence of oxygen. Initial selectivity analysis shows that three electron collision reactions are important for NOx evolution in O2/N2. The rate constants of these reactions decrease with increasing oxygen concentration. This is because oxygen is electronegative and thus reduces electron concentration. The rate constant of O2 dissociation by electron collision reaction is almost two orders of magnitude higher than that of N2 dissociation. NO formation occurs predominantly through N(2D) + O2 → NO + O. The critical oxygen concentration, defined as the concentration at which the NOx formation rate counterbalances the NOx decomposition rate, increases with increasing initial NO concentration. © 2005 American Institute of Chemical Engineers AIChE J, 2005
Metallcarbene mit niedriger Oxidationsstufe als Initiatoren für Olefinmetathesen und verwandte Reaktionen
Authors: Katz Thomas J.
Published: March 2005

Vor 24 Jahren wurden Experimente mit Tantalcarbenen durchgeführt, aus deren Ergebnissen die häufig zitierte Hypothese abgeleitet wurde, dass Metalle (außer Ruthenium) ihre maximale Oxidationsstufe aufweisen müssen, damit ihre Carbenderivate Olefinmetathesen auslösen können. Diese Hypothese berechtigt zu der Annahme, dass nur Molybdän‐ und Wolframcarbene mit hoher Oxidationsstufe wirksame Initiatoren sind. Sie legt auch nahe, dass die schon früher als Initiatoren für Olefinmetathesen und verwandte Reaktionen entdeckten Fischer‐Wolframcarbene oxidiert werden müssen, bevor sie wirksam werden können. Die neueren Initiatoren sind als “wohldefiniert”, die älteren als “undefiniert” bezeichnet worden. Entspricht das den Fakten?
Ligating behavior and metal uptake of N‐sulphonylpolyamine chelating resins anchored on polystyrene‐divinylbenzene beads
Authors: Jeragh Bakir J. A. , Elassar Abdel‐Zaher A. , El‐Dissouky Ali
Published: March 2005

Amberlite XAD‐2 has been functionalized by coupling through –SO2‐with ethylenediamine, propylenediamine, and diethylenetriamine to give the corresponding polyamine chelating resins I–III. The solid metallopolymer complexes of the synthesized chelating resins with Cu2+, Zn2+, Cd2+, and Pb2+ were synthesized. The polyamine derivatives and their metal complexes were characterized by elemental analysis, spectral (IR, UV/V, and ESR), and magnetic studies. The batch equilibrium method was utilized for using the chelating polyamines for the removal of Cu+2, Zn+2, Cd+2, and Pb+2 ions from aqueous solutions at different pH values and different shaking times at room temperature. The selective extraction of Cu+2 from a mixture of the four metal ions and the metal capacities of the chelating resins were evaluated using atomic absorption spectroscopy. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 1839–1846, 2005
Graft copolymerization of sodium salt of partially carboxymethylated guar gum with methyl methacrylate: An examination of the reaction variables
Authors: Trivedi J. H. , Kalia Kiran , Patel N. K. , Trivedi H. C.
Published: March 2005

The graft copolymerization of methyl methacrylate (MMA) onto sodium salt of partially carboxymethylated guar gum (Na‐PCMGG; degree of substitution = 0.497) with ceric ammonium nitrate as a redox initiator in an aqueous medium was studied. The optimized reaction conditions affording the maximum percentage of grafting of MMA onto Na‐PCMGG were determined through the variation of the concentrations of nitric acid, ceric ammonium nitrate, MMA, and Na‐PCMGG and of the temperature and time. The effects of these parameters on the grafting yields and the rates of polymerization, graft copolymerization, and homopolymerization were also studied, and the results were examined. The graft copolymer sample was characterized with IR spectroscopy, thermogravimetric analysis, differential scanning calorimetry, and scanning electron microscopy. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 1855–1864, 2005
Formation of polymer nanocomposites with various organoclays
Authors: Kim Younghoon , White James L.
Published: March 2005

The role of the type of organic modifier used with montmorillonite (MMT) on the formation of polymer/clay nanocomposites in the melt compounding process was investigated. Various organoclays including primary [12‐aminolauric acid (12ALA)], secondary [dioctylamine (DOA)], tertiary [trioctylamine (TOA)], and two commercial quaternary (Cloisite 30B and 20A) MMTs were melt compounded with carefully selected polymers including polypropylene, polystyrene, styrene–acrylonitrile copolymer, poly(methyl methacrylate), poly(vinylidene fluoride), and acrylonitrile–butadiene copolymer (NBR). X‐ray diffraction and transmission electron microscopy characterizations confirmed that the two quaternary ammonium organoclay (Cloisite 30B and 20A) have superior compatibility compared to the primary (12ALA), secondary (DOA), and tertiary (TOA) ammonium organoclay. DOA and TOA can form polymer/clay nanocomposites only with the most polar polymer (NBR). Cloisite Na+ and 12ALA can not form nanocomposite with any polymers. The large organic surface area of the quaternary ammonium organoclay could be the reason of the best compatibility with polar polymers. It is estimated that long alkyl ammonium chains of organic modifier can spread over the clay surface more effectively than short alkyl chains. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 1888–1896, 2005
Synthesis, characterization, and applications of polyvinylpyrrolidone/SiO2 hybrid materials
Authors: Hsiao C. N. , Huang K. S.
Published: March 2005

This research discusses the properties of hybrid materials formed by polyvinylpyrrolidone (PVP) and tetraethoxysilane (TEOS) of different weight ratios, by the sol–gel process, to evaluate the feasibility of its application to process‐dyed nylon fabrics. After using equipment including FTIR, 13C‐NMR, and SEM, it was shown that PVP and SiO2 are connected by hydrogen bonds, further showing the existence of special functional groups and the porous structure in hybrid materials. The pore size of the hybrid materials, specific volume of pores, and the specific surface area increased with increasing weight ratio of TEOS. In addition, the TGA testing results showed that the thermoresistance of hybrid materials can be improved. The color of the treated fabrics darkened if dyed nylon fabrics were treated by hybrid materials. When using metal complex acid dye for certain fabrics, when hybrid materials were used in finishing, there was significant improvement to the fabric's hygroscopicity and its colorfastness against chlorine. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 1936–1942, 2005
One‐component epoxy resin with imine as water‐initiated latent hardener: Improvement of the mechanical and adhesive properties by the addition of methacrylate copolymer
Authors: Suzuki Kentarou , Sugita Yuko , Sanda Fumio , Endo Takeshi
Published: March 2005

The effect of addition of methacrylate polymer into a one‐component epoxy resin, containing Epikote 828 and diimine as a water‐initiated hardener, was examined. Although the cured epoxy resin in the presence of methyl methacrylate–butyl acrylate (MMA–BA) copolymer was very brittle, the resin containing MMA–BA–[γ‐(methacryloxy)propyl]trimethoxysilane (TMSMA) copolymer showed good mechanical and adhesive properties. The adhesive strength of the cured epoxy resin containing MMA–BA–TMSMA copolymer was much higher than that without its polymer. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 1943–1949, 2005
Modeling of semibatch styrene suspension polymerization processes
Authors: Lenzi Marcelo Kaminski , Cunningham Michael F. , Lima Enrique Luis , Pinto José Carlos
Published: March 2005

We developed a mathematical model to describe the behavior of semibatch styrene suspension polymerization processes, where the constituents of a typical emulsion polymerization process are added into the reaction vessel during the course of a typical suspension reaction. This technique was recently described for the production of core–shell polymer particles. The model assumes that the nucleated emulsion particles can agglomerate with the sticky and much bigger suspension particles and that the agglomeration rate constant is a function of the internal states of the suspended droplets. The proposed model presented good agreement with experimental conversion, average molecular weight, and molecular weight distribution data. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 1950–1967, 2005
Novel biodegradable amino acid containing anhydride oligomers for orthopedic applications
Authors: Xie Dong , Chung Ildoo , Puckett Aaron D. , Mays Jimmy W.
Published: March 2005

Novel synthetic biodegradable methacrylated anhydride oligomers (MAOs) based on methacrylated alaninyl maleamic acid (MAMA) and methacrylated aminocaproyl maleamic acid (MACMA) were synthesized and characterized. Injectable and in situ crosslinkable polymer networks were formulated by the copolymerization of MAOs with triethylene glycol dimethacrylate (TEGDMA). Furthermore, composites composed of MAOs, TEGDMA, and β‐tricalcium phosphate were prepared. The networks and composites were initiated by photopolymerization and redox polymerization, respectively. The initial compressive strength (CS) and diametral tensile strength (DTS) of these materials were determined and used to evaluate the effects of the MAO/TEGDMA ratios on the degradation behavior of the materials. The MAMA‐based composites had initial DTS values of 5.7–17.1 MPa and CS values of 30.7–114.2 MPa. The MACMA‐based composites had initial DTS values of 2.8–20.8 MPa and CS values of 19.1–119.5 MPa. During the course of degradation, the neat polymer resins lost 97 and 87% of their initial CS values after 6 months with 50/50 MAMA/TEGDMA and MACMA/TEGDMA ratios, respectively. The composite with a 25/75 MACMA/TEGDMA ratio showed a significant increase in CS after an initial decrease for 7 days and then lost 57% of its initial CS value after 3 months. The composite composed of 100% methacrylated anhydride oligomer (MAOs) showed complete degradation after 21 days. The degrees of conversion of the neat resins were 60–77%. Both the neat resins and the composites had low polymerization shrinkage ranging from 3.8 to 5.6%. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 1979–1984, 2005
Adsorption of certain amino acids onto crosslinked diethylaminoethyl dextran microbeads
Authors: Tayfur Muhittin , Güner Ali
Published: March 2005

The adsorption dynamism of certain amino acids [alanine (Ala), serine (Ser), lysine (Lys), proline (Pro), and aspartic acid (Asp)] on crosslinked diethylaminoethyl (DEAE) dextran microbeads was investigated with electronic spectroscopy in aqueous solutions. Among the selected amino acids, Ala‐Pro and Ser‐Lys showed similar adsorption dynamism, but Asp showed the strongest tendency for adsorption. The interaction dynamism of Asp with crosslinked DEAE dextran microbeads was studied to determine the mechanism of this adsorption. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 1985–1991, 2005
The clustering power of low frequency words in academic Webs
Authors: Price Liz , Thelwall Mike
Published: March 2005

The value of low frequency words for subject‐based academic Web site clustering is assessed. A new technique is introduced to compare the relative clustering power of different vocabularies. The technique is designed for word frequency tests in large document clustering exercises. Results for the Australian and New Zealand academic Web spaces indicate that low frequency words are useful for clustering academic Web sites along subject lines; removing low frequency words results in sites becoming, on average, less dissimilar to sites from other subjects.
Fluorene and phenanthrene uptake by Pseudomonas putida ATCC 17514: Kinetics and physiological aspects
Authors: Rodrigues Ana C. , Wuertz Stefan , Brito António G. , Melo Luís F.
Published: March 2005

Pseudomonas putida ATCC 17514 was used as a model strain to investigate the characteristics of bacterial growth in the presence of solid fluorene and phenanthrene. Despite the lower water‐solubility of phenanthrene, P. putida degraded this polycyclic aromatic hydrocarbon (PAH) at a maximum observed rate of 1.4 ± 0.1 mg L−1 h−1, higher than the apparent degradation rate of fluorene, 0.8 ± 0.07 mg L−1 h−1. The role of physiological processes on the biodegradation of these PAHs was analyzed and two different uptake strategies were identified. Zeta potential measurements revealed that phenanthrene‐grown cells were slightly more negatively charged (–57.5 ± 4.7 mV) than fluorene‐grown cells (–51.6 ± 4.9 mV), but much more negatively charged than glucose‐grown cells (–26.8 ± 3.3 mV), suggesting that the PAH substrate induced modifications on the physical properties of bacterial surfaces. Furthermore, protein‐to‐exopolysaccharide ratios detected during bacterial growth on phenanthrene were typical of biofilms developed under physicochemical stress conditions, caused by the presence of sparingly water‐soluble chemicals as the sole carbon and energy source for growth, the maximum value for TP/EPS during growth on phenanthrene (1.9) being lower than the one obtained with fluorene (5.5). Finally, confocal laser microscopy observations using a gfp‐labeled derivative strain revealed that, in the presence of phenanthrene, P. putida::gfp cells formed a biofilm on accessible crystal surfaces, whereas in the presence of fluorene the strain grew randomly between the crystal clusters. The results showed that P. putida was able to overcome the lower aqueous solubility of phenanthrene by adhering to the solid PAH throughout the production of extracellular polymeric substances, thus promoting the availability and uptake of such a hydrophobic compound. © 2005 Wiley Periodicals, Inc.
Biomass characteristics and membrane aeration: Toward a better understanding of membrane fouling in submerged membrane bioreactors (MBRs)
Authors: Germain Eve , Stephenson Tom , Pearce Pete
Published: March 2005

Fouling in submerged membrane bioreactors (MBRs) was studied under different operating conditions and with varying biomass characteristics. Fouling rates were determined using a flux‐step method for seven biomass conditions with mixed liquor solids concentrations ranging from 4.3 to 13.5 g.l−1, six permeate fluxes (5.5, 11.0, 16.5, 22.0, 27.5, and 33.0 l.m−2.h−1), and three membrane airflow velocities (0.07, 0.10, and 0.13 m.s−1). Statistical analysis was used to specify the degree of influence of each of the biomass characteristics (solids concentration, dewaterability, viscosity, particle size distribution, concentrations of protein and carbohydrate in the soluble microbial products, SMP, and extracellular polymer substances, EPS), the permeate flux and the membrane aeration velocity on the membrane fouling rate. Among all these variables, only the permeate flux, the solids concentration (correlated to the viscosity and the dewaterability), the carbohydrate concentration in the EPS, and the membrane aeration velocity were found to affect the fouling rate. The permeate flux had the greatest effect. A transitional permeate flux was observed between 16.5 and 33 l.m−2.h−1, below which no significant fouling was observed regardless of the biomass characteristics, the permeate flux, and the membrane aeration velocity. © 2005 Wiley Periodicals, Inc.
Temperature‐triggered purification of antibodies
Authors: Kim Jae‐Young , Mulchandani Ashok , Chen Wilfred
Published: March 2005

In this article the unique capability of elastin‐like protein (ELP) to reversibly precipitate was combined with the high affinity and specificity of antibody‐binding domains such as Protein G, Protein L, or Protein LG as a general method for antibody purification that combines in a unique manner the simplicity and robustness of temperature‐triggered precipitation with the selectivity of affinity interactions. In a single precipitation step, antibodies derived from different sources (animal sera or hybridoma cell cultures) were selectively recovered by a simple temperature trigger. Due to the versatility of the binding ligands toward different classes of antibodies, we believe that this technology will be useful as an economical, highly efficient, and universal platform for the purification of antibodies. © 2005 Wiley Periodicals, Inc.
Measuring social influence of a senior midwife on decision‐making in maternity care: an experimental study
Authors: Hollins Martin Caroline , Bull Peter
Published: March 2005

The document Changing Childbirth produced by the Department of Health (1993) requests provision of more choice, continuity and control for women during pregnancy and childbirth. In this context this study considers whether midwives'decisions are influenced by a senior midwife. A simple, valid and reliable scale—the Social Influence Scale for Midwifery (SIS‐M)—was devised to measure and score midwives' private anonymous responses to 10 clinical decisions. The SIS‐M was initially administered as a self‐completed postal survey by 209 midwives. Following a 9‐month time gap, a stratified sample of 60 (20 E, F, G grade midwives) were invited for interview in which a senior midwife attempted to influence SIS‐M responses in a conformist direction. Overall, a 3 × 2 (E, F, G grade midwives x private and interview SIS‐M scores) analysis of variance (ANOVA) revealed midwives were significantly more conformist when influenced by a senior midwife, in comparison to private anonymous responses. No significant interaction between groups was found. These findings indicate that there is influence of a senior midwife on clinical decisions that should be woman‐centred, according to Changing Childbirth (1993). The implication is that this influence may remove choice from women. Copyright © 2005 John Wiley & Sons, Ltd.
Lomustine (chloroethylnitrosourea [CCNU]), ifosfamide, bleomycin, vincristine, and cisplatin (CIBO‐P) is an effective regimen for patients with poor prognostic refractory or multiple disease recurrent aggressive non‐Hodgkin lymphoma
Authors: Musolino Antonino , Perrone Maria Antonietta , Michiara Maria , Delnevo Daniela , Franciosi Vittorio , Di Blasio Beatrice , Ceci Guido , Camisa Roberta , Ardizzoni Andrea , Cocconi Giorgio
Published: March 2005

BACKGROUND

The current study was designed to assess the activity and safety of a novel combination therapy for patients with recurrent or refractory aggressive non‐Hodgkin lymphoma (NHL).

METHODS

Forty‐three consecutive patients with recurrent or refractory aggressive NHL were treated with lomustine (chloroethylnitrosourea [CCNU]; 60 mg/m2on Day 1), ifosfamide (1.5 g/m2on Days 1, 2 and 21, 22), bleomycin (5 mg/m2on Days 1, 5 and 21, 25), vincristine (1.4 mg/m2on Days 1, 8 and 21, 28), and cisplatin (25 mg/m2on Days 3, 4, 5 and 23, 24, 25), every 42 days (CIBO‐P regimen).

RESULTS

Thirty‐nine patients (91%) were evaluable for response. The median patient age was 63 years. Thirty‐five percent of the patients had received ≥ 2 lines of previous chemotherapy and 40% had elevated lactate dehydrogenase levels at the time of treatment initiation. The overall objective response rate was 77% (95% confidence interval [95% CI], 63–90%), including 19 (49%) complete (CR) and 11 (28%) partial responses. CIBO‐P induced responses in primary refractory disease and in patients treated for second or subsequent disease recurrences. A CR with previous therapy was the most important factor associated with a significantly higher CR rate. The median duration of response was 6 months (95% CI, 4.4–7.7 months) and the median survival duration was 10.7 months (95% CI, 5.9–18.1 months). Five patients (11.6%) remained disease free for ≥ 24 months. By multivariate analysis, a CR with previous therapy and average dose intensity of CIBO‐P drugs were independent prognostic factors for time‐to‐treatment failure, whereas a CR with previous therapy and serum lactate dehydrogenase were independent predictors for survival. Myelosuppression was the most frequent serious complication of this regimen. However, none of the patients had hemorrhage with thrombocytopenia, and only 2 patients (5%) had febrile neutropenia.

CONCLUSIONS

In the current study, CIBO‐P was a novel, highly active, and safe combination therapy for patients with refractory disease with a poor prognosis or for patients with multiply recurrent aggressive NHL. Cancer 2005. © 2005 American Cancer Society.
Surface‐Enhanced Raman Scattering of p‐Aminothiophenol on a Au(core)/Cu(shell) Nanoparticle Assembly
Authors: Cao Linyou , Diao Peng , Tong Lianming , Zhu Tao , Liu Zhongfan
Published: March 2005

Surface‐enhanced Raman scattering (SERS) of p‐aminothiophenol (PATP) molecules adsorbed onto assemblies of Au(core)/Cu(shell) nanoparticles is reported. We compare it with the SERS spectrum of PATP adsorbed onto gold nanoparticles: both the absolute and relative scattered intensities of various bands in the two spectra are very different. The difference in relative intensity can be ascribed to chemical effects; the chemical enhancement ratio of the two substrates is ≈3–5. A theoretical analysis based on a charge‐transfer model is carried out, which yields a consistent result and shows that the difference in chemical enhancement is mainly due to the state densities and Fermi levels of the substrates. The difference in absolute intensity originates from electromagnetic (EM) enhancement. EM enhancement of Au(core)/Cu(shell) nanoparticles is unlike that of single‐component gold or copper SERS‐active substrates. The core/shell particle size for optimal enhancement is about 20 nm in the case of a 632.8 nm incident laser (the size ratio of the core and shell layers is about 0.6).
Numerical solution of the Boltzmann equation by time relaxed Monte Carlo (TRMC) methods
Authors: Pareschi Lorenzo , Trazzi Stefano
Published: March 2005

A new family of Monte Carlo schemes has been recently introduced for the numerical solution of the Boltzmann equation of rarefied gas dynamics (SIAM J. Sci. Comput. 2001; 23:1253–1273). After a splitting of the equation the time discretization of the collision step is obtained from the Wild sum expansion of the solution by replacing high‐order terms in the expansion with the equilibrium Maxwellian distribution. The corresponding time relaxed Monte Carlo (TRMC) schemes allow the use of time steps larger than those required by direct simulation Monte Carlo (DSMC) and guarantee consistency in the fluid‐limit with the compressible Euler equations. Conservation of mass, momentum, and energy are also preserved by the schemes. Applications to a two‐dimensional gas dynamic flow around an obstacle are presented which show the improvement in terms of computational efficiency of TRMC schemes over standard DSMC for regimes close to the fluid‐limit. Copyright © 2005 John Wiley & Sons, Ltd.
Nonlinearity in the Fed's monetary policy rule
Authors: Kim Dong Heon , Osborn Denise R. , Sensier Marianne
Published: March 2005

This paper investigates the nature of nonlinearities in the monetary policy rule of the US Federal Reserve (Fed) using the flexible approach to nonlinear inference. We find that while there is significant evidence of nonlinearity for the period to 1979, there is little such evidence for the subsequent period. Possible asymmetries in the Fed's reactions to inflation deviations from target and the output gap in the 1960s and 1970s may tell part of the story, but do not capture the entire nature of the nonlinearity. The inclusion of the interaction between inflation deviations and the output gap, as recently proposed, appears to characterize the nonlinear policy rule more adequately. Copyright © 2005 John Wiley & Sons, Ltd.
Nonparametric bounds on the returns to language skills
Authors: González Libertad
Published: March 2005

This paper applies the theoretical literature on nonparametric bounds on treatment effects to the estimation of how limited English proficiency (LEP) affects wages and employment opportunities for Hispanic workers in the United States. I analyse the identifying power of several weak assumptions on treatment response and selection, and stress the interactions between LEP and education, occupation and immigration status. I show that the combination of two weak but credible assumptions provides informative upper bounds on the returns to language skills for certain subgroups of the population. Adding age at arrival as a monotone instrumental variable also provides informative lower bounds. Copyright © 2005 John Wiley & Sons, Ltd.
Dental adhesive compounds alter glutathione levels but not glutathione redox balance in human THP‐1 monocytic cells
Authors: Noda M. , Wataha J. C. , Lewis J. B. , Kaga M. , Lockwood P. E. , Messer R. L. W. , Sano H.
Published: March 2005

The use of hydrophilic dental monomers in dentin bonding agents has vastly improved resin–dentin bond strengths, but incomplete polymerization of these monomers and their leaching into adjacent (pulpal) oral tissues has raised concerns about their biocompatibility. The sublethal effects of these resins are virtually unknown, but their electrophilic nature led to the hypothesis that they may alter cellular oxidative stress pathways. Glutathione balance between reduced (GSH) and oxidized (GSSG) is a major mechanism by which cells maintain redox balance and was therefore the focus of the current investigation. THP‐1 human monocytic cells were exposed to hydroxyethyl methacrylate (HEMA), benzoyl peroxide (BPO), camphorquinone (CQ), or triethyelene glycol dimethacrylate (TEGDMA) for 24 h at sublethal doses, then GSH and GSSG levels were measured by means of Ellman's method adapted for cell culture. The results indicate that these dental resin compounds act at least partly via oxidative stress by increasing GSH levels at sublethal concentrations. However, the GSH‐GSSG ratio was relatively unaffected. Only BPO altered the GSH‐GSSG ratio at 24 h, again at sublethal levels (7.5–15 μmol/L). The results support the hypothesis that resin monomers act, at least in part, via oxidative stress, and that oxidative‐stress pathways should be one focus of future investigations of monomer biocompatibility. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater
Study on new solvent extraction systems for erythromycin
Authors: Li Zhou , Qin Feng , Bao Hao , Gu Xueqiang
Published: March 2005

New solvent systems for the extraction of erythromycin were studied in which octanol was used as the extractant instead of butyl acetate. The mechanism for these new extraction systems is not simple physical distribution but the formation of a neutral complex of erythromycin. A neutral extraction complex formed between the neutral molecules of erythromycin and extractant by hydrogen bonding, and the formed neutral extraction complex moves into the organic phase. Extraction reaction equations and mathematical models of extraction equilibrium and re‐extraction equilibrium are proposed for these new extraction systems. Experimental results show that the new extraction systems offer technological and economic advantages owing to the low solubility of the extraction solvents in the aqueous phase. The solvent consumption of the new extraction process was less than 3kg per billion active units compared with 9–10 kg per billion active units for a butyl acetate extraction system. In addition, the recovery of solvent from raffinate may be eliminated, thus reducing energy consumption. Copyright © 2005 Society of Chemical Industry
Comparison between photocatalytic ozonation and other oxidation processes for the removal of phenols from water
Authors: Beltrán Fernando J , Rivas F Javier , Gimeno Olga
Published: March 2005

Photocatalytic ozonation (1O3 + VUV + TiO2), ozonation (O3), catalytic ozonation (O3 + TiO2), ozone photolysis (O3 + VUV), photocatalysis (TiO2 + VUV) and photolysis (VUV) have been compared in terms of formation of intermediates, extent of, mineralization (TOC, COD, chloride, nitrate) and kinetics in the aqueous treatment of three phenols (phenol, p‐chlorophenol and p‐nitrophenol). In all cases, photocatalytic ozonation led to lower degradation times for chemical oxygen demand and total organic carbon removal. Intermediates formed were similar in the different oxidation systems with some exceptions. They can be classified into three different types: polyphenols (resorcinol, catechol, hydroquinone), unsaturated carboxylic acids (maleic and fumaric acids) and saturated carboxylic acids (glyoxylic, formic and oxalic acids). First order kinetic equations have been checked for the oxidation processes studied in the case of the parent compound. Rate constants of these systems have also been calculated. Copyright © 2005 Society of Chemical Industry
Placentation in the Mexican lizard Sceloporus mucronatus (Squamata: Phrynosomatidae)
Authors: Villagrán Maricela , Méndez Fausto R. , Stewart James R.
Published: March 2005

We used light microscopy to study placental structure of the lizard Sceloporus mucronatus throughout 6 months of embryonic development. Three stages of placental development could be assigned to embryos based on the arrangement of the extraembryonic membranes. A highly vascular choriovitelline placenta was present in the embryonic hemisphere and a nonvascular bilaminar omphalopleure covered most of the abembryonic hemisphere of the egg during embryonic Stages 10–28. A chorioallantoic placenta replaced the choriovitelline placenta by embryonic Stage 29 and an omphaloplacenta covered the abembryonic hemisphere at this stage. The combination of these two placental types occurred in Stage 29–36 embryos. The final stage of placentation, embryonic Stages 37–40, was characterized by an omphalallantoic placenta in the abembryonic hemisphere and a chorioallantoic placenta in the embryonic hemisphere of the egg. The choriovitelline and chorioallantoic placentae are well vascularized, with closely apposed maternal and embryonic blood vessels. These structures are the most likely sites of respiratory exchange. In contrast, the omphaloplacenta and omphalallantoic placentae contain cuboidal or columnar epithelia and these structures may function in histotrophic exchange. Placentation of S. mucronatus is similar to that of predominantly lecithotrophic species in other squamate lineages suggesting that the evolution of this placental morphology is a response to similar factors and is independent of phylogeny. J. Morphol. © 2005 Wiley‐Liss, Inc.
Gel extracted from Khruea‐ma‐noi (Cyclea barbataMiers) leaves: chemical composition and gelation properties
Authors: Arkarapanthu Apasara , Chavasit Visith , Sungpuag Pongtorn , Phuphathanaphong Leena
Published: March 2005

Gel extracted from Khruea‐ma‐noi leaves, which are widely consumed by villagers in Northeast Thailand, has a unique characteristic that could be used for food and nutritional applications, such as in therapeutic diets and in the food industry. Since little is known scientifically about this plant, this study identified the plant's scientific name and determined the chemical composition of the Khruea‐ma‐noi polymer and its gelling mechanism. Results reveal that Khruea‐ma‐noi is classified asCyclea barbataMiers. Its main polymer is polygalacturonic acid of average molecular weight 741 kDa with 66.3% methylated. Dried powders of extract and purified gels contained 415 and 724 g kg−1of soluble dietary fiber and 7.1 and 13.9 g kg−1of divalent cations, respectively. Factors affecting gelling ability and characteristics include phenolic compounds, oxidizing and reducing agents, pH, divalent cations and temperature. Most gels formed were thermoreversible except at pH 7. Copyright © 2005 Society of Chemical Industry
Sorption isotherms, GAB parameters and isosteric heat of sorption
Authors: Quirijns Elisabeth J , van Boxtel Anton JB , van Loon Wilko KP , van Straten Gerrit
Published: March 2005

The diffusion–sorption drying model has been developed as a physics‐based way to model the decreasing drying rate at low moisture contents. This new model is founded on the existence of different classes of water: free and bound water. The transition between these classes and the corresponding thermodynamics form distinct components of the drying model. This paper shows that the characteristics of the different classes of water and of the transition between them can be deduced from the GAB sorption isotherm. The parameters in the GAB sorption isotherm support the theory of localised sorption, establishing the existence of different classes of water. Moreover, the sorption mechanism retrieved from the GAB parameters is in accordance with the sorption mechanism, which is obtained from the moisture dependence of the net isosteric heat of sorption. This holds for experimental sorption data of corn and starch as well as for literature data on five vegetables and four fortified cassava products. An extremum in the net isosteric heat of sorption coincides with the transition between bound and free water, and the partition moisture content corresponds with the monolayer value derived from the GAB equation. This confirms that the GAB monolayer value can be chosen as model boundary between bound and free water. Moreover, it reveals that this method can be developed into a technique to estimate the bound water content in foods. Copyright © 2005 Society of Chemical Industry
Development of lipid oxidation during manufacturing of horse mackerel surimi
Authors: Eymard Sylvie , Carcouët Elodie , Rochet Marie‐Joëlle , Dumay Justine , Chopin Christine , Genot Claude
Published: March 2005

When fatty fish are transformed into surimi, lipid oxidation takes place, decreasing the quality of the product. This study was aimed to identify the critical stages of the process in terms of the development of lipid oxidation. Horse mackerels were transformed into surimi on a pilot line and samples taken (hand‐skinned fillets = minced fillets, mince, washed and refined minces, paste, surimi and washing water). Most of the lipids were removed during the process and neutral lipids were lost in higher proportion than polar lipids. As a consequence, total lipids of surimi contained more polyunsaturated fatty acids (338 ± 19 g kg−1) than total lipids of the minced fillets (220 ± 8 g kg−1). Thiobarbituric acid reactive substances (TBARS) was higher in the minced fillets than in the mince because less subcutaneous fat and dark muscle were removed during hand‐mincing, indicating that the settings of the skinning–deboning machine can strongly influence the final quality of the product. Concentrations of lipid oxidation products increased significantly during the next stages of surimi processing. The increase was more pronounced for TBARS than hydroperoxides. Concentrations in hydroperoxides were similar in mince and washed mince (15.3 ± 2.8 and 16.6 ± 2.8 mmoles kg−1 lipid) and increased in refined mince (29.6 ± 2.8 mmoles kg−1 lipid). TBARS accounted for 2.7 ± 1.0 mg kg−1 lipid in mince, 40.4 ± 2.3 mg kg−1 lipid in washed mince and 237 ± 7 mg kg−1 lipid in refined mince. Hydroperoxides and TBARS were found in appreciable amounts in washing water (76.9 ± 4.7 mmoles kg−1 lipid and 479 ± 8 mg kg−1 lipid respectively), when they decreased in surimi (27.3 ± 3.8 mmoles kg−1 lipid and 44.2 ± 0.8 mg kg−1 lipid respectively) compared with refined mince. This shows that the last dewatering stage is crucial to ensure surimi quality. Copyright © 2005 Society of Chemical Industry
Prediction of fat in intact cereal food products using near‐infrared reflectance spectroscopy
Authors: Kays Sandra E , Archibald Douglas D , Sohn Miryeong
Published: March 2005

To evaluate the feasibility of an intact product approach to the near‐infrared (NIR) determination of fat content, a rapid acquisition spectrometer, with an InGaAs diode‐array detector and custom built sampling device, was used to obtain reflectance spectra (1100–1700 nm) of diverse cereal food products. Fat content reference data were obtained gravimetrically by extraction with petroleum ether (AOAC Method 945.16). Using spectral and reference data, partial least‐squares regression analysis was applied to calculate a NIR model (n = 89) to predict fat in intact cereal products; the model was adequate for rapid screening of samples, predicting the test samples (n = 44) with root mean square error of prediction (RMSEP) of 11.8 (range 1.4–204.8) g kg−1 and multiple coefficient of determination of 0.98. Repeated repacking and rescanning of the samples did not appreciably improve model performance. The model was expanded to include samples with a broad range of particle sizes and moisture contents without reduction in prediction accuracy for the untreated samples. The regression coefficients for the models calculated indicated that spectral features at 1165, 1215 and 1395 nm, associated with CH stretching in fats, were the most critical for model development. Published in 2005 for SCI by John Wiley & Sons, Ltd.
Validation of the alkane technique to estimate diet selection of goats grazing heather–gorse vegetation communities
Authors: Ferreira Luis MM , Oliván Mamen , Garcia Urce , Rodrigues Miguel AM , Osoro Koldo
Published: March 2005

The effect of n‐alkane faecal recovery on the accuracy of diet composition estimates, when increasing the number of diet components, was studied. Seven dietary treatments, composed of different proportions of herbaceous (Lolium perenne and Trifolium repens) and woody species (Erica umbellata, Erica cinerea, Calluna vulgaris, Erica arborea and Ulex gallii) were offered to 28 goats housed in metabolism crates. Diet composition was estimated from alkane concentrations in diet and faeces, with and without correction for incomplete faecal recoveries, using least‐squares procedures and was compared with the known diet proportions. There were no significant differences between measured proportions of dietary components and those estimated with alkanes when applying the faecal recovery corrections. In contrast, the proportions calculated without faecal recovery correction differed significantly (p < 0.05) from the actual proportions, overestimating feeds with higher content of long‐chain n‐alkanes. The diet composition affected significantly the faecal recovery of alkanes if there were significant differences on in vivo digestibility. The n‐alkane faecal recoveries decreased as the diet digestibility increased. The results obtained show that the application of the alkane methodology for grazing animals should be preceded by calculation of the actual alkane faecal recoveries for each type of vegetation community and experimental conditions. Copyright © 2005 Society of Chemical Industry
Effect of high hydrostatic pressure on quality parameters of lager beer
Authors: Buzrul Sencer , Alpas Hami , Bozoglu Faruk
Published: March 2005

Unpasteurized lager beer samples from a commercial brewery were treated either by high hydrostatic pressure (HHP; 200, 250, 300, 350 MPa for 3 and 5 min at 20 °C) or by conventional heat pasteurization (60 °C for 15 min). The main attributes of the beer, such as ethanol content, extract and pH, were not affected by either treatment; however HHP and heat pasteurization affected colour, chill haze, protein sensitivity and bitterness. Change in bitterness was higher in conventional heat pasteurization, but pressures up to 300 MPa had no significant affect on bitterness. Although more studies should be carried out to investigate the effects of HHP treatment on different types of lagers and ales, our results revealed that HHP could be successfully used to process beer, even at temperatures well below those required for heat pasteurization, without affecting some of the quality attributes. Copyright © 2005 Society of Chemical Industry
Influence of water activity and temperature on conidial germination and mycelial growth of ochratoxigenic isolates ofAspergillus ochraceuson grape juice synthetic medium. Predictive models
Authors: Pardo Ester , Lagunas Ursino , Sanchis Vincente , Ramos Antonio J , Marín Sonia
Published: March 2005

The first stages in the development ofAspergillus ochraceus, an ochratoxin A‐producing fungus that infects grapes and may grow on them, have been studied on a synthetic nutrient medium similar to grape in composition. Spore germination and mycelial growth have been tested over a water activity (aw) and temperature range which could approximate to the real conditions of fungal development on grapes. Optimal germination and growth were observed at 30 °C for all three isolates tested. Maximal germination rates were detected at 0.96–0.99awat 20 °C, while at 10 and 30 °C the germination rates were significantly higher at 0.99aw. Although this abiotic factor (aw) had no significant influence on mycelial growth, growth rates obtained at 0.98awwere slight higher than those at otherawlevels. Predictive models for the lag phase before spore germination as a function of water activity and temperature have been obtained by polynomial multiple linear regression, and the resulting response surface models have been plotted. Copyright © 2005 Society of Chemical Industry
Daily consumption of phenolics and total antioxidant capacity from fruit and vegetables in the American diet
Authors: Chun Ock Kyoung , Kim Dae‐Ok , Smith Nancy , Schroeder David , Han Jae Taek , Lee Chang Yong
Published: March 2005

The daily intake of total phenolics, total flavonoids and antioxidants in the American diet was estimated from the most common 34 fresh fruit and vegetables and their daily consumption data. Among 14 fruit and 20 vegetables, orange contributed the highest amount of total phenolics [117.1 mg gallic acid equivalent (GAE) person−1day−1] and antioxidants [146.6 mg vitamin C equivalents (VCE) person−1day−1]. Orange contributed about 26 and 25% of total phenolics and antioxidant, respectively, in the daily consumption of fruit and vegetables. Apples showed relatively high levels of total phenolics and antioxidant capacity comparable to those of oranges and their phenolics and antioxidants contribution is the second highest. Even though potatoes had lower levels of phenolics and antioxidant capacity, they were third due to the fact that their consumption is the highest (137.9 lb person−1year−1) in the American diet. Although plums and strawberries were ranked as the group with the highest total phenolics and antioxidant capacity among 34 tested fruit and vegetables, their contributions were relatively low due to their lower daily consumption. Generally, the levels of total phenolics, total flavonoids and antioxidant capacity of fruits were higher than those of vegetables. American daily intake of phenolics, flavonoids and antioxidants from fruits and vegetables was estimated to be 450 mg GAE, 103 mg catechin equivalents and 591 mg VCE, respectively. Although we do not yet know the required minimum daily amounts of antioxidants, when we estimate the daily requirement of antioxidants, we must consider not only the antioxidant concentrations of the particular food, but also the daily intakes of the food. Copyright © 2005 Society of Chemical Industry
Chemical composition, nutritive value and voluntary intake of tropical tree foliage and cocoyam in pigs
Authors: Leterme Pascal , Londoño Angela M , Estrada Fernando , Souffrant Wolfgang B , Buldgen André
Published: March 2005

The composition of the leaves of cocoyam (Xanthosoma sagittifolium) and of two trees (Trichanthera giganteaand mulberry,Morus alba), their nutritive value in pigs and voluntary intake by pigs were determined. The average protein content ranged from 170 to 240 g kg−1dry matter (DM) and that of neutral detergent fibres from 218 to 398 g kg−1DM. The leaves are interesting sources of calcium (up to 69 g kg−1DM), potassium, iron and manganese. The proteins are well balanced in essential amino acids, with lysine ranging from 43 to 57 g kg−1proteins. The apparent faecal digestibility was determined by difference in 35 kg pigs fed a diet containing 35% leaf meal. The digestibility coefficients of DM, N and energy were, respectively, 47–57, 33–36 and 51–53%. The digestible energy value ranged from 1.674 to 2.037 kcal kg−1DM. The voluntary intake ofTrichantheraandXanthosomawas measured in sows weighing 100 kg on average. The intake reached 3.4 kg fresh leaves day−1(0.51 kg DM) and 1.0–1.1 kg dry leaf meal/day. It is concluded that low energy density is the main limiting factor of tree foliage for pig nutrition but that they are good sources of minerals and well‐balanced proteins. Copyright © 2005 Society of Chemical Industry
Phospholipase A2‐dependent effects of the venom from the new guinean small‐eyed snake Micropechis ikaheka
Authors: Kuruppu Sanjaya , Isbister Geoffrey K. , Hodgson Wayne C.
Published: March 2005

The New Guinean small‐eyed snake (Micropechis ikaheka) is a cause of life‐threatening envenoming. Previous studies on M. ikaheka venom have indicated the presence of neurotoxins as well as myotoxins. This study examined the in vitro myotoxic effects of M. ikaheka venom and the efficacy of a polyvalent antivenom in neutralizing these effects. Venom (50 μg/ml) produced a slowly developing contracture and inhibition of direct twitches of the chick biventer cervicis nerve–muscle preparation in the presence of tubocurarine (10 μM). Myotoxicity was confirmed by subsequent histological examination of tissues. This myotoxicity was prevented by the prior addition of polyvalent snake antivenom (30 U/ml). However, the addition of antivenom (30 U/ml) 1 h after venom administration failed to reverse or prevent the further inhibition of direct twitches. In addition, venom (1–10 μg/ml) produced concentration‐dependent contractions of the guinea‐pig isolated ileum. These effects were dependent on phospholipase A2 (PLA2) activity of the venom as evidenced by the ability of the PLA2 inhibitor 4‐bromophenacyl bromide (4‐BPB; 1.8 mM) to prevent this activity. This study indicates that M. ikaheka venom causes significant myotoxicity and that polyvalent snake antivenom may be a potential treatment for the myotoxic effects in patients envenomed by this species. Muscle Nerve, 2005