bluuebunny/crossref_metadata_2025_split huggingface dataset:
Comparing median lethal concentration values using confidence interval overlap or ratio tests
Authors: Wheeler Matthew W , Park Robert M. , Bailer A. John 
Published: April 2006

Abstract
Experimenters in toxicology often compare the concentration-response relationship between two distinct populations using the median lethal concentration (LC50). This comparison is sometimes done by calculating the 95% confidence interval for the LC50 for each population, concluding that no significant difference exists if the two confidence intervals overlap. A more appropriate test compares the ratio of the LC50s to 1 or the log(LC50 ratio) to 0. In this ratio test, we conclude that no difference exists in LC50s if the confidence interval for the ratio of the LC50s contains 1 or the confidence interval for the log(LC50 ratio) contains 0. A Monte Carlo simulation study was conducted to compare the confidence interval overlap test to the ratio test. The confidence interval overlap test performs substantially below the nominal α = 0.05 level, closer to p = 0.005; therefore, it has considerably less power for detecting true differences compared to the ratio test. The ratio-based method exhibited better type I error rates and superior power properties in comparison to the confidence interval overlap test. Thus, a ratio-based statistical procedure is preferred to using simple overlap of two independently derived confidence intervals.
Anaerobic transformation of a technical brominated diphenyl ether mixture by super-reduced vitamin B12 and dicyanocobinamide
Authors: Gaul Simon , von der Recke Roland , Tomy Gregg , Vetter Walter 
Published: April 2006

Abstract
The anaerobic transformation of the technical octabromo diphenyl ether mixture, DE-79, was investigated by incubation with two super-reduced corrinoids, dicyanocobinamide and cyanocobalamin (vitamin B12). The transformation produced 33 brominated diphenyl ethers (BDEs), 23 of which could be assigned to known structures. Within 1 d, the hepta- to nona-BDEs in DE-79 were almost quantitatively transformed with dicyanocobinamide to lower-brominated homologs. Along with the decrease of high-brominated congeners, concentrations of some tetra- to hexabromo congeners initially increased, followed by a decreasing or constant concentration during longer incubations. Super-reduced cyanocobalamin also was able to transform BDE congeners of DE-79. Whereas the transformation rates of hepta- to nona-BDEs of DE-79 by both corrinoids were comparable, tri- to hexa-BDEs were susceptible to further transformation by super-reduced cyanocobalamin. Incubation of DE-79 with either corrinoid produced significant amounts of BDE 49. Because this congener is found in small quantities in both penta- and octabromo technical BDE mixtures, it may be a suitable indicator for reductive debromination of higher-brominated BDEs. Isolated BDE 196 was incubated as well with super-reduced dicyanocobalamine. After 1 d, 13 BDEs could be detected, with BDE 153, BDE 100, and BDE 99 dominating. After 7 d, only tetra-BDEs or lower-brominated BDEs were detectable. It could be shown that reductive debromination by super-reduced corrinoids is a possible source for lower-brominated BDEs (i.e., BDE 47, BDE 99, BDE 153, and BDE 154). The patterns observed with our bench-scale study design demonstrate that anaerobic transformation in the presence of reducing agents can help to explain the occurrence of environmentally relevant BDE congeners (e.g., BDE 47, BDE 99, and BDE 153).
Chemical characterization of brominated flame retardants and identification of structurally representative compounds
Authors: Andersson Patrik L. , Öberg Kjell , Örn Ulrika 
Published: April 2006

Abstract
Three training sets were selected, each consisting of 10 structurally diverse compounds representative of brominated flame retardants (BFRs) that are either in use or have been used. Just three compounds account for nearly all the total production volume of BFRs. In the present study, however, the physicochemical characteristics of a far more structurally diverse set of 65 BFRs was explored using 15 molecular descriptors (including log P, constitutional counts, and semiempirical quantum mechanical parameters) and principal component analysis (PCA). The PCA generated an overview of the structural variation among BFRs, and certain compounds with unique physicochemical properties and specific clusters of compounds with distinct properties were identified. The training-set compounds were selected by applying the condensed information obtained from the PCA and statistical experimental design. The three training sets, which were designated as optimal, practical, and alternative, were selected either to maximize the structural variation (optimal) or to combine structural variation with practical advantages, such as ease of experimental handling and commercial availability (practical and alternative). Inclusion of the suggested compounds in assessments of the persistence, bioaccumulation, and toxicity properties of BFRs and related programs should help to increase our understanding of the effects and environmental fate of these compounds.
Development of a solvent-free, solid-phase in vitro bioassay using vertebrate cells
Authors: Bopp Stephanie K. , Bols Niels C. , Schirmer Kristin 
Published: April 2006

Abstract
Miniaturized bioassays offer many advantages in exploring the toxic potential of chemicals, including small sample volumes and compatibility with high-throughput screening. One problem common to miniaturized systems, however, is the loss of test chemicals because of sorption. The idea of the current study was to use the sorption phenomenon in a positive way. It was found that contaminants sorbed to the growth surface in wells of tissue-culture plates or to the surface of selected sorbent bead materials are available to vertebrate cells growing in direct contact with the contaminant-coated surface. The use of beads provided more flexibility with regard to surface area, materials, and assay format. Biosilon, a bead cell-culture carrier made of polystyrene, was found to be most suitable. It supported cell adherence and allowed the detection of reproducible dose-response curves of an increase in cytochrome CYP1A enzyme activity by sorbed polycyclic aromatic hydrocarbons in the rainbow trout (Oncorhynchus mykiss) liver cell line, RTL-W1. The resulting bead assay provides a miniaturized, solvent-free exposure system. Potential future applications include the coupling to environmental sampling, in which the bead material is used as solid receiving phase before serving as a surface for vertebrate cells to attach and respond.
Cytotoxicity and aryl hydrocarbon receptor-mediated activity of N-heterocyclic polycyclic aromatic hydrocarbons: Structure-activity relationships
Authors: Sovadinová Iva , Bláha Luděk , Janošek Jaroslav , Hilscherová Klára , Giesy John P. , Jones Paul D. , Holoubek Ivan 
Published: April 2006

AbstractToxic effects of many persistent organic pollutants (e.g., polychlorinated biphenyls or polychlorinated dibenzo-p-dioxins and furans) are mediated via the aryl hydrocarbon receptor (AhR). Although polycyclic aromatic hydrocarbons (PAHs) and their derivatives also activate AhR, their toxic effects remain to be fully elucidated. In the present study, we used the in vitro H4IIEluc transactivation cell assay to investigate cytotoxicity and potencies to activate AhR by 29 individual PAHs and their N-heterocyclic derivatives (aza-PAHs). The aza-PAHs were found to be significantly more cytotoxic and more potent inducers of AhR than their unsubstituted analogues. Several aza-PAHs, such as dibenz[a,h]acridine or dibenz[a,i]acridine, activated AhR within picomolar concentrations, comparable to the effects of reference 2,3,7,8-tetrachlorodibenzo-p-dioxin. Ellipsoidal volume, molar refractivity, and molecular size were the most important descriptors derived from the modeling of quantitative structure-activity relationships for potencies to activate AhR. Comparable relative toxic potencies (induction equivalency factors) for individual aza-PAHs are derived, and their use for evaluation of complex contaminated samples is discussed.
How quality and quantity of organic matter affect polycyclic aromatic hydrocarbon desorption from Norwegian harbor sediments
Authors: Oen Amy M. P. , Breedveld Gijs D. , Kalaitzidis Stavros , Christanis Kimon , Cornelissen Gerard 
Published: April 2006

AbstractThe desorption behavior of phenanthrene, pyrene, and benzo[a]pyrene was investigated for three Norwegian harbor sediments and their respective particle size fractions using the Tenax desorption method. Rate constants for rapidly, slowly, and very slowly desorbing fractions were on the order of 10−1, 10−2 to 10−4, and 10−4 to 10−6/h, respectively. Relatively small amounts were present in the rapidly desorbing fractions (Frapid: &lt;6% for phenanthrene, 3–19% for pyrene, and 1–12% for benzo[a]pyrene). With the exception of benzo[a]pyrene, these Frapid values were generally lower than median Frapid values obtained from more than 100 literature values for native polycyclic aromatic hydrocarbons (PAHs) (22% for phenanthrene, 29% for pyrene, and 8% for benzo[a]pyrene). To understand which parameters influence PAH desorption, relations between desorption behavior and the sediment characteristics were investigated. A significant positive correlation was found between the extent of slow and very slow desorption and the ratios of black carbon to total organic carbon, as well as the temperature at which 50 and 90%, respectively, of the organic matter was oxidized, as obtained from oxidation-only Rock Eval analysis. Thus, black carbon-bound PAHs probably desorb slowly and very slowly. Furthermore, significant positive correlations between desorption behavior and the average particle size were observed, which could be explained by retarded intraparticle diffusion.
Bicontinuous microemulsions as adsorbents for liquid‐phase separation/purification
Authors: Tricoli V. , Farnesi M. , Nicolella C. 
Published: April 2006

AbstractNovel concepts of liquid‐phase adsorption at the oil/water interface of a bicontinuous microemulsive phase are presented. These ideas are assessed using a tetradecane/didodecyldimethylammonium bromide/water bicontinuous microemulsion (BME) to adsorb chromate anions from aqueous solution. The adsorption isotherms are investigated as a function of solution ionic strength. Our results show that the BME is an effective adsorbent for removing CrO from solutions with good selectivity over Br− and high enrichment ratio, arising from the large internal surface area of the oil/water interface. An approximate model adsorption isotherm is derived from basic thermodynamic considerations. The proposed model is validated against our experimental data with satisfactory agreement for low chromium content in the BME. Implications of these concepts and results for adsorptive separation of generic contaminant from a liquid phase are discussed in comparison with conventional adsorption processes using solid adsorbents and also with micellar‐enhanced ultrafiltration process. © 2006 American Institute of Chemical Engineers AIChE J, 2006
A model for the spray zone in early‐stage fluidized bed granulation
Authors: Schaafsma S. H. , Vonk P. , Kossen N. W. F. , Hoffmann A. C. 
Published: April 2006

AbstractThe formation of granules in the spray zone of a top‐spray fluid‐bed granulation process using a known and uniform drop‐size is studied experimentally and theoretically. Experimental results indicate a multi‐modal size distribution of spherically‐shaped granules. A model is presented to explain this based on the formation of nuclei, and the rapid coalescence of some of these nuclei with droplets or other nuclei in the spray zone of the bed. The model is based on a Bernoulli process and predicts the number frequency of granules to which n droplets have contributed. The model predictions are validated with experimental results for granule size distribution, and the nucleus residence time in the spray zone required to bring model predictions and experimental results into line is shown to be physically plausible by comparing with PEPT tracking of an agglomerate‐like tracer particle. © 2006 American Institute of Chemical Engineers AIChE J, 2006
High‐risk cutaneous squamous cell carcinoma of the head and neck
Authors: Veness Michael J. , Palme Carsten E. , Morgan Gary J. 
Published: April 2006

AbstractBACKGROUNDMost patients with cutaneous squamous cell carcinoma (cSCC) of the head and neck (HN) are at low‐risk (< 5%) of developing metastatic SCC to regional lymph nodes. However, patients with unfavorable clinicopathologic factors often are under appreciated by clinicians but remain at higher risk for developing metastatic lymph node disease and dying.METHODSPatients were identified who had metastatic cSCC to lymph nodes (parotid and cervical) of the HN and who were treated within the context of a multidisciplinary HN cancer service between 1980 and 2005 at Westmead Hospital (Sydney, Australia). Relevant patient details and data from primary lesions were analyzed and reported.RESULTSIn total, 266 patients were treated with curative intent. The median patient age was 69 years among 219 males and 47 females. The majority of metastatic lymph nodes (162 of 266 lymph nodes; 61%) were located in the parotid with or without cervical lymph node involvement. The median tumor thickness was 6 mm (range, 0.5–28 mm), and the median tumor size was 15 mm (range, 3–70 mm). Most tumors (65%) that measured ≥5 mm in thickness, and 30% of patients had lesions that measured ≥2 cm in greatest dimension. Recurrent cSCC was present in 15% of patients, and most lesions were located within the lymphatic drainage of the parotid on the temple/forehead (28%), on or around the ear (20%), or on the cheek (12%). Forty‐six percent of patients had moderately or poorly differentiated cSCC, and 5% of patients were immunosuppressed. A minority of patients (27%) did not have an identifiable index lesion.CONCLUSIONSData from this large, prospective data base, in concordance with other series, suggested that a patient with thick cSCC (>4–5 mm) located in proximity to the parotid gland can be considered at high‐risk. Increasing lesion size and recurrence contribute to this risk. Cancer 2006. © 2006 American Cancer Society.
Patterning the heart, a template for human cardiomyocyte development
Authors: Chuva de Sousa Lopes Susana M. , Hassink Rutger J. , Feijen Alie , van Rooijen Marga A. , Doevendans Pieter A. , Tertoolen Leon , Brutel de la Rivière Aart , Mummery Christine L. 
Published: April 2006

AbstractAlthough in mice, the dynamics of gene expression during heart development is well characterized, information on humans is scarce due to the limited availability of material. Here, we analyzed the transcriptional distribution of Mlc‐2a, Mlc‐1v, Mlc‐2v, and atrial natriuretic factor (ANF) in human embryonic hearts between 7 and 18 weeks of gestation and in healthy and hypertrophic adult hearts by in situ hybridization and compared expression with that in mice. Strikingly, Mlc‐2a, Mlc‐1v, and ANF, which are essentially chamber‐restricted in mice by mid‐gestation, showed a broader distribution in humans. On the other hand, Mlc‐2v may prove to be an adequate ventricular marker in humans in contrast to mouse. This study emphasizes the importance of careful comparative human–animal analyses during embryonic development and adulthood, as avoiding erroneous extrapolations may be critical to develop new and successful myocardial replacement therapies. Development Dynamics 235:1994–2002, 2006. © 2006 Wiley‐Liss, Inc.
The effect of self‐designed bifunctional RGD‐containing fusion protein on the behavior of human keratinocytes and dermal fibroblasts
Authors: Wang Tzu‐Wei , Wu Hsi‐Chin , Huang Yi‐Chau , Sun Jui‐Sheng , Lin Feng‐Huei 
Published: April 2006

AbstractIn this study, self‐designed bifunctional RGD‐containing fusion protein (BFP) was grafted on the petri dish to evaluate its cytotoxicity and attachment efficiency on primary cultured keratinocytes and dermal fibroblasts. Two lengths of the GRGDS sequences were separately fused to the N‐terminus and C‐terminus of the Trichoderma koningii cellobiohydrolase I gene cellulose‐binding domain, to serve as linking molecule between the cell and the substrate. The grafting procedure was no more labor‐intensive and could be done just in aqueous condition itself. The epidermal keratinocytes and dermal fibroblasts, harvested and separated from human foreskin, were cultured in serum‐free keratinocyte culture medium and DMEM, respectively. The BFP was dissolved in double‐deionized water, and was prepared at different concentrations. The BFP solution was subsequently added into the petri dish for grafting. MTT assay, total DNA measurement, and lactate dehydrogenase analysis were used to evaluate the cell viability, cell proliferation, and cytotoxicity. The immunochemical stain and SEM examination were chosen to make sure that the cultured cells still kept in phenotype. The results showed that the self‐designed BFP was successfully coated on the petri dish to improve the cells' adhesion. The whole coating procedure was just done in aqueous solution without any organic solvent being involved. This method was much simpler than the traditional one, and there was no possibility to damage the immobilized biomolecules. From the results of the study, BFP could enhance attachment of keratinocytes and dermal fibroblasts without losing normal cell morphology and keep keratinocytes on the desired differentiation pathway. We believe that coating BFP on petri dish not only enhanced the keratinocyte attachment but also promoted keratinocytes proliferation. We suggest that the self‐designed BFP has a great potential to apply on surface modification for the tissue‐engineering scaffolds in the future. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2006
Modification of HTPB‐based polyurethane with temperature‐sensitive poly(N‐isopropyl acrylamide) for biomaterial usage
Authors: Yang Jen Ming , Yang Shu Jyuan , Lin Hao Tzu , Chen Jan Kan 
Published: April 2006

AbstractHydroxyl‐terminated polybutadiene (HTPB)‐based polyurethane with dimethyol propionic acid (DPA) as chain extender was synthesized by solution polymerization. The HTPB‐based polyurethane was modified by UV radiation with N‐isopropyl acrylamide monomer to get poly(N‐isopropyl acrylamide)‐modified polyurethane (PUDPANIPAAm). The cohesive energy (Ecoh), molar volume (V), solubility parameter (δ), molecular weight (WM), volume per gram (Vg), and the density (1/Vg) of PUDPANIPAAm were calculated by group contribution methods. To evaluate the application of PUDPANIPAAm for wound dressing and transplantation of cell sheet, the measurement of water content, water vapor transmission rate, and gas permeation on the PUDPANIPAAm membrane was evaluated. The biocompatibility of these membranes, cell adhesion, and proliferation assay were conducted in the cell culture. The effect of thermosensitivity of poly(N‐isopropyl acrylamide) on cell detachment was also evaluated in the primary study. The results showed that these PUDPANIPAAm membranes are thermosensitive. The modification of PU with poly(N‐isopropyl acrylamide) reduced the water vapor transmission rate and permeability of gas through PUDPANIPAAm membrane. PUDPANIPAAm membranes could support cell adhesion and growth. Owing to the thermosensitive nature of poly(N‐isopropyl acrylamide), the relative cell numbers detached from PUDPANIPAAm membranes were larger than those detached from the polystyrene dish. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2007
Preparation and Characterization of Nanostructured TiO2/Epoxy Polymeric Films
Authors: Sangermano Marco , Malucelli Giulio , Amerio Ezio , Bongiovanni Roberta , Priola Aldo , Di Gianni Anna , Voit Brigitte , Rizza Giancarlo 
Published: April 2006

AbstractSummary: Titania‐containing coatings were prepared by cationic photopolymerization of an epoxy resin either by dispersion of preformed TiO2 nanoparticles or by their in‐situ generation through a sol‐gel dual‐cure process. The kinetics of photopolymerization was evaluated by real‐time FT‐IR, studying the effect of the TiO2 concentration. The properties of cured films were investigated, showing an increase of hydrophilicity on the surface of the coatings with increasing TiO2 content. TEM analysis demonstrated that it is possible to achieve a significantly better control of the dispersion of the inorganic particles within the organic matrix by in‐situ generation of TiO2, thus completely avoiding macroscopic phase separation and obtaining homogeneous, transparent coatings.Bright‐field TEM micrograph for TIP20 dual‐cured film.imageBright‐field TEM micrograph for TIP20 dual‐cured film.
Restoration of shoulder function with nerve transfers in traumatic brachial plexus palsy patients
Authors: Terzis Julia K. , Kostas Ioannis , Soucacos Panayotis N. 
Published: April 2006

AbstractShoulder stabilization is of utmost importance in upper extremity reanimation following paralysis from devastating injuries. Although secondary procedures such as tendon and muscle transfers have been used, they never achieve a functional recovery comparable to that following successful reinnervation of the supraspinatus, deltoid, teres minor, and infraspinatus muscles. Early restoration of suprascapular and axillary nerve function through timely brachial plexus reconstruction offers a good opportunity to restore shoulder‐joint stability, adequate shoulder abduction, and external rotation function. Overall, in our series, 79% of patients achieved good and excellent shoulder abduction (muscle grade, +3 or more), and 55% of patients achieved good or excellent shoulder external rotation after reinnervation of the suprascapular nerve. The best results were seen when direct neurotization of the suprascapular nerve from the distal spinal accessory nerve or neurotization by the C5 root was carried out. Concomitant neurotization of the axillary nerve yields improved outcomes in shoulder abduction and external rotation function. © 2006 Wiley‐Liss, Inc. Microsurgery, 2006.
Simultaneous synthesis of silver nanoparticles and poly(2,5‐dimethoxyaniline) in poly(styrene sulfonic acid)
Authors: Huang Li‐Ming , Tsai Ching‐Chun , Wen Ten‐Chin , Gopalan A. 
Published: April 2006

AbstractSilver nanoparticles were formed in situ along with poly(2,5‐dimethoxyaniline) (PDMA) in an interconnected network matrix (reactor), comprising the electronic conductive polymer, PDMA, and a polyelectrolyte, poly(styrene sulfonic acid) (PSS), through the simultaneous reduction of Ag+ ions and polymerization of 2,5‐dimethoxyaniline. In situ ultraviolet‐visible spectroscopy showed that peaks corresponding to the plasmon resonance of silver nanoparticles at 411 nm and the polaronic transition of PDMA at 438 nm provided evidences for the simultaneous formation of silver nanoparticles and PDMA. Transmission electron microscopy and size distribution analysis revealed the presence of spherical silver nanoparticles with an average diameter of 12 nm in the composite. X‐ray photoelectron spectroscopy showed that the amine units in PDMA changed to imine units upon the formation of silver nanoparticles. A comprehensive mechanism for the formation of the PDMA‐PSS‐Ag nanocomposite is proposed. A 10‐fold increase in the conductivity was noticed for the PDMA–PSS–Ag nanocomposite (1 S/cm) in comparison with the PDMA–PSS composite (0.1 S/cm). © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 3843–3852, 2006