bluuebunny/crossref_metadata_2025_split huggingface dataset:
The French paradox
Authors: Logan Barry A. , Hammond Matthew P. , Stormo Benjamin M. 
Published: January 2008

AbstractPlant‐derived phenolic compounds such as those found in red wine, tea, and certain fruit juices may protect against cardiovascular disease by detoxifying (scavenging) superoxide and other unstable reactive oxygen species. We present a laboratory exercise that can be used to assess the superoxide‐scavenging capacity of beverages. Among the beverages examined, only those known to be rich in phenolic compounds (red wine, green tea, blueberry juice, and stout beer) exhibited appreciable superoxide scavenging. White wine and a 10% ethanol solution served as controls and did not scavenge superoxide.
Cooperative learning combined with short periods of lecturing
Authors: Fernández‐Santander Ana 
Published: January 2008

AbstractThe informal activities of cooperative learning and short periods of lecturing has been combined and used in the university teaching of biochemistry as part of the first year course of Optics and Optometry in the academic years 2004–2005 and 2005–2006. The lessons were previously elaborated by the teacher and included all that is necessary to understand the topic (text, figures, graphics, diagrams, pictures, etc.). Additionally, a questionnaire was prepared for every chapter. All lessons contained three parts: objectives, approach and development, and the assessment of the topic. Team work, responsibility, and communication skills were some of the abilities developed with this new methodology. Students worked collaboratively in small groups of two or three following the teacher's instructions with short periods of lecturing that clarified misunderstood concepts. Homework was minimized. On comparing this combined methodology with the traditional one (only lecture), students were found to exhibit a higher satisfaction with the new method. They were more involved in the learning process and had a better attitude toward the subject. The use of this new methodology showed a significant increase in the mean score of the students' academic results. The rate of students who failed the subject was significantly inferior in comparison with those who failed in the previous years when only lecturing was applied. This combined methodology helped the teacher to observe the apprenticeship process of students better and to act as a facilitator in the process of building students' knowledge.
Problem‐solving test: The effect of in vitro bisulfite treatment on genomic DNA
Authors: Szeberényi József 
Published: January 2008

AbstractTerms to be familiar with before you start to solve the test: polymerase chain reaction, primer, promoter, restriction endonucleases, agarose gel electrophoresis, ethidium bromide staining, DNA methylation, Taq polymerase, single nucleotide polymorphisms, CpG islands, tumor suppressor genes, protooncogenes, epigenetic regulation
Use of a laboratory exercise on molar absorptivity to help students understand the authority of the primary literature
Authors: Soundararajan Madhavan , Bailey Cheryl P. , Markwell John 
Published: January 2008

AbstractTo promote understanding of the authority of the primary literature in students taking our biochemistry laboratory courses, a biochemistry laboratory exercise on the determination of an acceptable molar absorptivity value of 2‐nitrophenol (2‐NP) was developed. This made the laboratory course much more relevant by linking to a thematic thread, β‐galactosidase, that scaffolds concepts in one exercise with those in later exercises. The substrate for the continuous assay of β‐galactosidase is the chromogenic 2‐nitrophenyl‐β‐D‐galactopyranoside that produces 2‐NP. In an early laboratory exercise, students determine the wavelength of maximum absorption for the protonated and deprotonated form of 2‐NP at various pH values and then determine the molar absorptivity of 2‐NP. Students were encouraged to discuss apparent discrepancies not only in their own determinations of molar absorptivity values for 2‐NP, but also in the published molar absorptivity values for 2‐NP (2,150–21,300 M−1 cm−1) at almost the same pH and at 420 nm. Finally, the students were led to a publication that serves as an authentic source for molar absorptivity of 2‐NP.
Every Child Matters? A critical review of child welfare reforms in the context of minority ethnic children and families
Authors: Chand Ashok 
Published: January 2008

AbstractThis paper critically reviews some key government papers that together largely provide the foundation for the relevant child welfare reforms in England and Wales. The context of this review was to evaluate whether these papers and documents made sufficient reference to improving policies and practices for minority ethnic children and families involved in child welfare matters, given the research evidence from the early 1990s suggesting that such families may experience particular disadvantages or discriminations within the UK child welfare system. The research evidence cited draws upon studies that have considered the experiences of different minority ethnic groups from the point of referrals through to long term services, including those children who have been looked after in local authority care and those families that have been subject to care proceedings. This paper concludes that more is needed under the Every Child Matters agenda to both acknowledge and address the specific needs of minority ethnic children and their families, as identified in the range of studies published post Children Act 1989. Copyright © 2008 John Wiley & Sons, Ltd.
Oligodeoxynucleotides Containing 3‐Bromo‐3‐deazaadenine and 7‐Bromo‐7‐deazaadenine 2′‐Deoxynucleosides as Chemical Probes to Investigate DNA–Protein Interactions
Authors: Minakawa Noriaki , Kawano Yuri , Murata Shunpei , Inoue Naonori , Matsuda Akira 
Published: January 2008

AbstractWe describe the design and proof of concept of a pair of chemical probes for investigating DNA–protein interactions—specifically, the incorporation of 7‐bromo‐7‐deazaadenine and 3‐bromo‐3‐deazaadenine 2′‐deoxynucleosides (Br7C7dA and Br3C3dA) into oligodeoxynucleotides (ODNs)—and their utility. Whereas the bromo substituent of the Br7C7dA unit in an ODN duplex acts sterically to inhibit binding with NF‐κB, which interacts with the duplex in its major groove, the bromo substituent of the Br3C3dA unit acts sterically to inhibit binding with RNase H, which interacts with the duplex in its minor groove. In addition, the utilization of ODNs containing 7‐deazaadenine and 3‐deazaadenine 2′‐deoxynucleosides (C7dA and C3dA), together with the pair of chemical probes, afforded valuable information on the requirement for nitrogen atoms located in either the major or minor grooves. Accordingly, we were able to show the utility of ODNs containing Br7C7dA, Br3C3dA, C7dA, and C3dA for the investigation of DNA–protein interactions.
Syntheses of Ladder‐Type Oligonaphthalene Derivatives and Their Photophysical and Electrochemical Properties
Authors: Chen Jun‐Chun , Lee Tse‐Shi , Lin Chih‐Hsiu 
Published: January 2008

AbstractLadder‐type oligophenylene derivatives are important compounds for light‐emitting devices. However, the closely related ladder‐type oligonaphthalene derivatives have received little attention due to the lack of synthetic accessibility. We hereby report the syntheses of these novel conjugated systems by means of an intramolecular cationic cyclization protocol. Utilizing a one‐pot–multiple‐component reaction, the acyclic precursors to these ladder‐type oligomers up to pentamer can be synthesized from small fragments in just two or three steps. Photophysical and electrochemical studies revealed that the electron delocalization in these compounds is considerably enhanced relative to that found in the regular unplanarized oligonaphthalene derivatives. However, such an effect is much weaker than that found in fully planar rylene derivatives.
Asymmetric Synthesis of (+)‐Altholactone: A Styryllactone Isolated from Various Goniothalamus Species
Authors: Enders Dieter , Barbion Julien 
Published: January 2008

AbstractThe asymmetric total synthesis of (+)‐altholactone (1), a member of the styryllactone family of natural products displaying cytotoxic and antitumor activities, is described. Key steps include a RAMP‐hydrazone α‐alkylation (RAMP=(R)‐1‐amino‐2‐methoxymethylpyrrolidine) of 2,2‐dimethyl‐1,3‐dioxan‐5‐one, a boron‐mediated aldol reaction, a six‐ to five‐membered ring acetonide shuffling, an oxidative 1,5‐diol to δ‐lactone conversion and a stereoselective ring‐closure to generate the annulated tetrahydrofuran moiety with inversion of configuration.
Organophosphates and Synthetic Musk Fragrances in Freshwater Streams in Hessen/Germany
Authors: Quednow Kristin , Püttmann Wilhelm 
Published: January 2008

AbstractFour small freshwater river systems in Hessen, Germany, have been investigated with respect to seasonal and spatial concentration variations and transported load of the organophosphates tri‐n‐butyl phosphate (TBP), tris(2‐butoxyethyl)phosphate (TBEP), tris(2‐chloroethyl)phosphate (TCEP), tris(1‐chloro‐2‐propyl)phosphate (TCPP), and tris(1,3‐dichloro‐2‐propyl)phosphate (TDCPP) and the synthetic musk fragrances 1,3,4,6,7,8‐hexahydro‐4,6,6,7,8,8‐hexa‐methylcyclopenta‐[γ]‐2‐benzopyran (HHCB) and 7‐acetyl‐1,1,3,4,4,6‐hexamethyl‐1,2,3,4‐tetrahydronaphthalene (AHTN). Data originate from water samples collected in the time span from September 2003 to April 2005 at 25 sampling locations. The detection frequency for all compounds was about 90%. Mean concentration levels of organophosphates were 502 ng/L (TCPP), 276 ng/L (TBP), 183 ng/L (TBEP), 118 ng/L (TCEP), and 117 ng/L (TDCPP). The synthetic musk fragrances HHCB and ATHN were detected with mean concentrations of 141 and 46 ng/L, respectively. The variability of the concentration of all compounds was high with respect to space and time. The highest concentrations were observed in the Schwarzbach system characterized by the highest proportion of wastewater compared to the other river systems. Concentration levels of synthetic musk fragrances were significantly lower in summer times compared to winter times.
Biodiversity in the Benthic Diatom Community in the Upper River Töss Reflected in Water Quality Indices
Authors: Kupe Lirika , Schanz Ferdinand , Bachofen Reinhard 
Published: January 2008

AbstractBiodiversity in benthic diatom communities was determined to assess the ecological state and to evaluate changes in water quality in time and space in the prealpine part of the river Töss (Switzerland). One site upstream and three sites downstream from the inlet of a communal waste water treatment plant (WWTP) were analyzed during 1996/97. In total, 67 diatom species were detected and the relative abundance of each taxon determined. The Shannon Diversity Index and the Saprobic Index were calculated and related to the newly developed Swiss Trophic Diatom Index. Dominant species belonged to the genera Achnanthes, Amphora, Cymbella, Diatoma, Gomphonema, Navicula, and Nitzschia. The species composition and the abundance of the diatom species present varied over the seasons, but changes in the chemical parameters or the flow regime had little effect. The Shannon Index gave evidence of biodiversity variations over the seasons and some differences between sampling sites. The Saprobic Index oscillated within a small band, indicative for oligo‐mesosaprobic conditions. It could not identify significant changes in water quality between sampling sites and over the seasons. The Swiss Trophic Diatom Index differentiated better between sampling sites and seasons and gave values corresponding to a β‐mesosaprobic state. Preliminary data from 2005 and 2006 give no evidence of a change in water quality during the last decade.
Pilot‐Scale Degradation of Organic Contaminants in a Continuous‐flow Reactor by the Helielectro‐Fenton Method
Authors: Casado Juan , Fornaguera Jordi 
Published: January 2008

AbstractThe feasibility of pilot‐scale mineralization of organic pollutants in wastewaters using the Electro‐Fenton® process is demonstrated. The treatment was applied in a continuous‐flow reactor, to solutions of nitrobenzene, 2,4‐D and benzoic acid and to actual wastewaters from a fine chemicals company along with a pulp and paper company. The results showed mineralization yields from 60 to 84% by simply applying the Electro‐Fenton® process. When a subsequent exposure to sunlight was carried out (Helielectro‐Fenton method), this mineralization almost went to completion, except for the effluent from the fine chemicals industry.
Semi‐Micro Reflux Procedure for Minimization of Chloride Interference by COD Determination
Authors: Martins Ayrton F. , de Jesus Lucas E. W. , Vendruscolo Nádia , Vasconcelos Tibiriçá G. , Wilde Marcelo L. 
Published: January 2008

AbstractIn this study, a semi‐micro procedure for the COD (Chemical Oxygen Demand) was undertaken to allow the measurement of effluent samples with a high chloride content. It was found that the COD values for standard and effluent samples, corresponded closely to those obtained using the standard method of Burns and Marshall. When the method was applied to samples of industrial wastewater, with a very high chloride content, the recommended procedure proved to be accurate and precise, with RSDs of 6% and 4.3% for the standard and effluent solutions, respectively. The required amount of hazardous reagents was similar to that found in the standard closed reflux method. It was also possible to determine the total amount of oxidized halides. The use of this low‐cost, laboratory‐made system made it unnecessary to acquire an expensive, imported analytical system, while maintaining a high level of accuracy in the determinations.
Epidermal growth factor receptor immunohistochemistry
Authors: Hirsch Fred R. , Dziadziuszko Rafal , Thatcher Nick , Mann Helen , Watkins Claire , Parums Dinah V. , Speake Georgina , Holloway Brian , Bunn Paul A. , Franklin Wilbur A. 
Published: January 2008

AbstractBACKGROUNDThe ISEL (Iressa Survival Evaluation in Lung Cancer) clinical trial evaluated the efficacy of gefitinib versus placebo in pretreated nonsmall‐cell lung cancer patients. Two different antibodies, scoring systems, and cutoff points of epidermal growth factor receptor (EGFR) protein expression were compared to predict response and survival of enrolled patients.METHODSEGFR expression was assessed in tumor samples by immunohistochemistry using the Dako EGFR pharmDx kit (scoring percent of tumor cells with positive staining) and Zymed monoclonal antibody clone 31G7 (scoring staining index derived from proportion of positive cells times staining intensity).RESULTSData for EGFR expression were available for 379 patients for Dako and 357 patients for Zymed antibody (22% and 21%, respectively, of trial population). Objective response rates in gefitinib‐treated EGFR‐positive patients defined with various cutpoints with Dako antibody varied between 8% and 12%, and with Zymed antibody between 10% and 13%. Lower cutoff points with Dako antibody provided the best discrimination between EGFR‐positive and EGFR‐negative patients for survival hazard ratios comparing gefitinib to placebo, with a significant treatment/cutoff point interaction for 10% cutoff point (P = .049). A similar but less apparent trend was noted for Zymed antibody, although the discrimination between hazard ratios was not significant for any cutoff point analyzed.CONCLUSIONSAssessment with the Dako PharmDx kit and percentage of cells with positive staining may provide more accurate prediction of differential effect on survival with gefitinib than assessment with Zymed antibody and staining index. Using higher cutpoints to define positivity does not improve test discrimination. Cancer 2008. © 2008 American Cancer Society.
Exploring the Optical Activity Tensor by Anisotropic Rayleigh Optical Activity Scattering
Authors: Zuber Gérard , Wipf Peter , Beratan David N. 
Published: January 2008

AbstractRayleigh optical activity (RayOA) spectroscopy promises to provide an elegant and robust analytical method to probe molecular stereochemistry. A careful selection of RayOA variants such as right‐angle depolarized ICP (incident circular polarization) or backscattering DCPI (in‐phase dual circular polarization) allows analysis of the anisotropic component of the scattered light. In this study, we show that calculated anisotropic Rayleigh optical activity quantities provide key advantages over isotropic chiroptical quantities (such as optical rotation and RayOA variants dominated by isotropic invariants): 1) higher sensitivity for probing the chiroptical tensor G′, 2) reduced dependence on small geometry changes, and 3) much less stringent computational demand for predicting an accurate sign than for optical rotation. Moreover, the stereochemical information provided by anisotropic RayOA and its invariants can be used to develop chirality descriptors because of the apparent correlation between structure/stereochemistry and the sign and magnitude of the anisotropic Rayleigh optical activity quantities.
Theoretical Investigation of the Second‐Shell Mechanism of Nitrile Hydratase
Authors: Hopmann Kathrin H. , Himo Fahmi 
Published: January 2008

AbstractNitrile hydratases (NHases) are biocatalytically important enzymes that are utilized in the industrial production of acrylamide and nicotinamide. There are two different classes of NHases, harbouring either a low‐spin FeIII or a low‐spin CoIII ion in the active site, in each case with the same peculiar set of ligands, involving deprotonated backbone amides and oxidized cysteine residues. The detailed reaction mechanism of NHase has not been established yet, but different proposals have been put forward. Depending on the binding site of the substrate, these can be divided into first‐shell and second‐shell mechanisms, respectively. Recently, we have investigated different first‐shell mechanisms using quantum‐chemical active‐site models based on the iron‐dependent NHase (Inorg. Chem. 2007, 46, 4850). Here we continue our investigation of the NHase reaction by exploring two different variations of the second‐shell mechanism of the iron‐dependent NHase. In the first, a metal‐bound hydroxide ion performs a nucleophilic attack on the nitrile substrate, while in the second investigated mechanism, the oxidized cysteine, Cys114‐SO–, acts as the nucleophile. We report energies, optimized transition state, and intermediate geometries for both investigated mechanisms. The calculated barriers are similar to the previously reported first‐shell mechanism involving Cys114‐SO– as catalytic base. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
Profiles of volatile compounds in milk containing fish oil analyzed by HS‐SPME‐GC/MS
Authors: Jimenez‐Alvarez Diego , Giuffrida Francesca , Golay Pierre‐Alain , Cotting Claudia , Destaillats Frédéric , Dionisi Fabiola , Keely Brendan 
Published: January 2008

AbstractLong‐chain polyunsaturated fatty acids (LC‐PUFA) have various positive biological effects. Fish oil represents a major source of LC‐PUFA; therefore it is extensively used to enrich food products as, for example, infant formulae, dairy products and fruit juices. However, in the presence of oxygen and metals, LC‐PUFA readily degrade, producing off‐flavors and decreasing the nutritional value of the product. The deterioration of sensory properties (taste and odor) can be easily perceived by the consumer, due to the formation of volatile compounds that are formed by decomposition of lipid hydroperoxides, also known as primary oxidation products. In this study, we used the headspace solid‐phase microextraction‐gas chromatography/mass spectrometry technique (HS‐SPME‐GC/MS) to characterize and quantify volatile compounds in a food matrix supplemented with fish oil. We demonstrated that the HS‐SPME‐GC/MS method is a valuable tool to monitor lipid oxidation at early stages. We identified t‐2‐hexenal and c‐4‐heptenal as possible oxidation markers during the storage of milk enriched with 5% of cod oil.
Approach to a New Dihydrofuran‐Fused Cyclic System by a Remarkable Switching of endo/exo Selectivity of a [4+2] Cyclo­addition Reaction
Authors: Matsuya Yuji , Imamura Yoshiaki , Miyahara Tatsuro , Ochiai Hiroshi , Nemoto Hideo 
Published: January 2008

AbstractAn efficient synthesis of a new class of dihydrofuran‐fused tetracyclic compounds, possessing a 2‐oxa‐furano‐steroidal framework, has been achieved by successive electrocyclic reactions of benzocyclobutene derivatives. It has been revealed that the stereoselectivity of a key intramolecular [4+2] cycloaddition reaction can be controlled by installation of a bulky silyl substituent onto the furan ring resulting in the formation of the exo adducts, the opposite selectivity to that observed in our past related studies. Preliminary examinations of the bioactivities of the synthesized compounds have been performed and have revealed that they have potential as anti‐influenza agents. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
Electrocatalytic Determination of Nitrite on a Rigid Disk Electrode Having Cobalt Phthalocyanine Prepared In Situ
Authors: Canevari Thiago C. , Luz Rita C. S. , Gushikem Yoshitaka 
Published: January 2008

AbstractThis work reports an in situ cobalt(II) phthalocyanine (CoPc) synthesis on a SiO2/SnO2 (SiSn) matrix surface obtained by the sol‐gel method and its electrocatalytic activity for oxidation of nitrite. A rigid disk electrode with SiSn/CoPc was used to study the electrooxidation of nitrite by the cyclic voltammetric, chronoamperometric techniques and differential pulse voltammetry (DPV). The adsorbed phthalocyanine electrocatalyzed nitrite oxidation at 0.73 V (versus SCE) using the DPV technique. The anodic peak current intensities, plotted from differential pulse voltammograms in 1 mol L−1 KCl for the concentration range 0.002 to 3.85 mmol L−1 of nitrite were linear, with a correlation coefficient of 0.998 and a detection limit of 0.95 μmol L−1.
Impedance Study of GaN and InGaN Semiconductor Anion Selective Electrodes
Authors: Dimitrova Rozalina , Catalan Lionel , Alexandrov Dimiter , Chen Aicheng 
Published: January 2008

AbstractThe response of potentiometric anion selective electrodes employing undoped GaN or In0.2Ga0.8N films as sensing element to detect various anions was investigated in solutions of KF, KNO3, KCl, HOC6H4COONa, KSCN, CH3COOK, KClO4 and KBr salts. The calibration plots for the GaN and In0.2Ga0.8N semiconductor electrodes contained linear regions extending over four decades of activity change in most solutions. The structure of the GaN and In0.2Ga0.8N semiconductor electrode/ electrolyte interface was studied through electrochemical impedance spectroscopy. Analogous equivalent circuits modeling the GaN or In0.2Ga0.8N electrode/electrolyte interface were proposed and their parameters were calculated. The space charge layer of the GaN and In0.2Ga0.8N semiconductors dominated the impedance of the electrochemical system at high frequencies (>10 kHz), whereas at low frequencies (<10 kHz), the impedance was controlled by the diffusion of electroactive species across the layer of adsorbed ions at the surface of the electrode. Results imply a strong dependence of the electrodes performance on the adsorption capacity of tested anions.