bluuebunny/crossref_metadata_2025_split huggingface dataset:
Novel Nano‐Structured Silica‐Based Electrolytes Containing Quaternary Ammonium Iodide Moieties
Authors: Cerneaux S. , Zakeeruddin S. M. , Pringle J. M. , Cheng Y.‐B. , Grätzel M. , Spiccia L. 
Published: September 2007

AbstractA series of new hybrid organic‐inorganic molecules were prepared either by grafting of aminopropyltriethoxysilane (APTS) on silica nanoparticles followed by quaternarization of the nitrogen with ethyl, heptyl and isopropyl iodides or by grafting of N,N,N‐triethyl‐3‐(triethoxysilyl)propan‐1‐aminium iodide and N,N,N‐tridodecyl‐3‐(triethoxysilyl)propan‐1‐aminium iodide onto the silica nanoparticles. These new materials were used as iodide sources in the preparation of electrolyte solutions for dye‐sensitized solar cells (DSSCs). The performance of DSSCs was studied as a function of the nature of the solvent, the nature of the dye, the concentration of the modified silica in the electrolyte system and the silica content introduced during the hybrid synthesis. An efficiency of 8.5 % was obtained for solar cells containing the triethyl ammonium iodide salt at a concentration of 1 M in either acetonitrile (AN) or 3‐methoxypropionitrile (MPN) under an illumination of 10 mW cm–2, the equivalent of 0.1 Sun at AM 1.5G. At 1 Sun (100 mW cm–2, efficiencies of 6.6 % and 5.1 % were recorded for the AN and MPN‐based electrolytes, respectively.
Atomic force microscopy observations of the topography of regenerated silk fibroin aggregations
Authors: Huang Tao , Ren Peng , Huo Bo 
Published: September 2007

AbstractHow fibroin molecules fold themselves and further self‐assemble into aggregations with specific structures when the solution concentration increases is the key to understanding the natural silk‐forming process of the silkworm. A regenerated Bombyx mori silk fibroin solution was prepared, and serially diluted solutions were coated on aminated coverslips. Atomic force microscopy (AFM) observations of the topography of fibroin molecules revealed a transformation from rodlike aggregations 100–200 nm long to small globules 50 nm in diameter with decreasing concentrations. When the incubation duration increased, the aggregations of fibroin molecules showed a self‐assembling process, which was measured with AFM. In particular, after the molecules were incubated for more than 20 min, rodlike micelles formed and were distributed evenly on the surface of the aminated slides. Flow chamber technology was used to study the effect of the shear loading on the topography of the fibroin molecular aggregations. After a shear loading was applied, larger rodlike particles formed at a higher incubation concentration in comparison with those at a lower concentration and were obviously oriented along the direction of fluid flow. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007
Spectroscopic and electrochemical studies on block‐polymer/PMMA blend based composite polymer electrolytes
Authors: Zhang Shupeng , Fu Xiangkai , Gong Yongfeng 
Published: September 2007

AbstractPoly(methylmethacrylate)(PMMA)/oxymethylene‐linked polyoxyethylene multi‐block polymer(Om‐POEn, where n represents number of unit CH2CH2O) blend based composite electrolyte films containing different lithium salt concentration and nanofillers' content are prepared using solvent evaporation technique. The interaction of polymer–salt complex has been confirmed using FTIR spectral studies. The figuration of CPE was studied by XRD. Ionic conductivity and thermal behavior of the CPEs were studied with various salt concentrations, temperature, and nanofillers' content. The surface structure of the CPE is also investigated using scanning electron microscopy. The high room temperature ionic conductivity, transmittivity in the visible region, and thermal stability make these CPEs potential candidates as solid‐like electrolytes for electrochemical devices. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007
Nanocomposite polymer electrolytes containing silica nanoparticles: Comparison between poly(ethylene glycol) and poly(ethylene oxide) dimethyl ether
Authors: Park Jung Tae , Lee Kyung Ju , Kang Moon‐Sung , Kang Yong Soo , Kim Jong Hak 
Published: September 2007

AbstractNanocomposite polymer electrolytes consisting of low molecular weight poly(ethylene oxide) (PEO), iodine salt MI (M = K+, imidazolium+), and fumed silica nanoparticles have been prepared and characterized. The effect of terminal group in PEO, i.e., hydroxyl (OH) and methyl (CH3) using poly(ethylene glycol) (PEG) and PEO dimethyl ether (PEODME), respectively, was investigated on the interactions, structures, and ionic conductivities of polymer electrolytes. Wide angle X‐ray scattering (WAXS), differential scanning calorimetry (DSC), and complex viscositymeasurements clearly showed that the gelation of PEG electrolytes occurred more effectively than that of PEODME electrolytes. It was attributed to the fact that the hydroxyl groups of PEG participated in the hydrogen‐bonding interaction between silica nanoparticles, and consequently helped to accelerate the gelation reaction, as confirmed by FTIR spectroscopy. Because of its interaction, the ionic conductivities of PEG electrolytes (maximum value ∼ 6.9 × 10−4 S/cm) were lower than that of PEODME electrolytes (2.3 × 10−3 S/cm). © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007
Nonoxynol‐9‐α‐cyclodextrin inclusion compound and its application for the controlled release of nonoxynol‐9 spermicide
Authors: Suk Whang Hyun , Hunt Marcus A. , Wrench Nicola , Hockney Jessica E. , Farin Charlotte E. , Tonelli Alan E. 
Published: September 2007

AbstractNonoxynol‐9 (N‐9) is the most active ingredient in commercially available spermicidal products in the United States. There are many applications of cyclodextrin inclusion complexes (CD‐ICs), but there are no reported studies investigating the formation of and controlled release from a N‐9 spermicide‐CD‐IC. We have successfully formed the inclusion compound between N‐9 and α‐CD using a solution‐heating technique. The N‐9‐α‐CD‐IC was characterized by Fourier Transform infrared spectroscopy, nuclear magnetic resonance spectroscopy, differential scanning calorimetry, thermogravimetric analysis, and wide angle X‐ray diffraction observations. Silicone elastomer (SILASTIC MDX4‐4210) film embedded with crystalline N‐9‐α‐CD‐IC was prepared and evaluated for its efficacy in the controlled release of N‐9 spermicide against bovine sperm. Silicone elastomer with N‐9‐α‐CD‐IC was as successful in reducing the motility and viability of bovine spermtazoa as silicone elastomer swollen with an equivalent amount of neat N‐9. The permeability of the flexible silicone elastomer apparently enables the N‐9 spermicide to diffuse from its embedded inclusion complex crystals to contact, immobilize, and kill bovine sperm cells. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007
Modification of polyethylene surface using plasma polymerization of silane
Authors: Deshmukh R. R. , Shetty A. R. 
Published: September 2007

AbstractIn the present study plasma polymerization of tetraethylorthosilicate and hexamethyldisiloxane was carried out on polyethylene film with an aim of enhancing barrier properties. The glow discharge was obtained at 0.2 mbar using 13.56 MHz radio frequency source capable of giving power out put up to 100 W. The monomer vapors were passed in the system at the rate of 15 SCCM. The extent of deposition was determined from the weight gain study and the morphology was studied using SEM. Films were further characterized by surface energy measurement, ATR‐FTIR and ESCA analysis. Since PE is widely used for packaging and in this process a thin layer of glass‐like transparent SiOx was deposited, therefore it was thought necessary to study permeability to water vapors. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007
Novel Deoxyxylulosephosphate‐Reductoisomerase Inhibitors: Fosmidomycin Derivatives with Spacious Acyl Residues
Authors: Ortmann Regina , Wiesner Jochen , Silber Katrin , Klebe Gerhard , Jomaa Hassan , Schlitzer Martin 
Published: September 2007

Abstract1‐Deoxy‐D‐xylulose‐5‐phosphate reductoisomerase (Dxr) represents an essential enzyme of the mevalonate‐independent pathway of the isoprenoid biosynthesis. Using fosmidomycin as a specific inhibitor of Dxr, this enzyme was previously validated as target for the treatment of malaria and bacterial infections. The replacement of the formyl residue of fosmidomycin by spacious acyl residues yielded inhibitors active in the micromolar range. As predicted by flexible docking, evidence was obtained for the formation of a hydrogen bond between an appropriately placed carbonyl group in the acyl residue and the main‐chain NH of Met214 located in the flexible catalytic loop of the enzyme.
Biodegradation of fuel oil hydrocarbons by a mixed bacterial consortium in sandy and loamy soils
Authors: Hawle‐Ambrosch Elisabeth , Riepe Wolfgang , Dornmayr‐Pfaffenhuemer Marion , Radax Christian , Holzinger Anita , Stan‐Lotter Helga 
Published: September 2007

AbstractThe aerobic degradation of light fuel oil in sandy and loamy soils by an environmental bacterial consortium was investigated. Soils were spiked with 1 or 0.1% of oil per dry weight of soil. Acetone extracts of dried soils were analyzed by GC and the overall degradation was calculated by comparison with hydrocarbon recovery from uninoculated soils. In sandy soils, the sum of alkanes n‐C12 to n‐C23 was degraded to about 45% within 6 days at 20°C and to 27–31% within 28 days, provided that moisture and nutrients were replenished. Degradation in loamy soil was about 12% lower. The distribution of recovered alkanes suggested a preferential degradation of shorter chain molecules (n‐C12 to n‐C16) by the bacterial consortium. Partial 16S rDNA sequences indicated the presence of strains of Pseudomonas aeruginosa, Pseudomonas citronellolis, and Stenotrophomonas maltophilia. Toxicity tests using commercial standard procedures showed a moderate inhibition of bacterial activity. The study showed the applicability of a natural microbial community for the degradation of oil spills into soils at ambient temperatures.
Function of the SIRT1 protein deacetylase in cancer
Authors: Stünkel Walter , Peh Bee Keow , Tan Yong Cheng , Nayagam Vasantha M. , Wang Xukun , Salto‐Tellez Manuel , Ni BinHui , Entzeroth Michael , Wood Jeanette 
Published: September 2007

AbstractThe NAD+‐dependent protein deacetylase SIRT1 is linked to cellular survival pathways by virtue of keeping the tumor suppressor gene p53 and members of the forkhead transcription factor family deacetylated. To validate SIRT1 as a therapeutic anti‐cancer target, we performed immunohistochemistry experiments to study the in vivo expression of SIRT1 in cancer specimens. We show that human SIRT1 is highly expressed in cancer cell lines as well as in tissue samples from colon carcinoma patients. Interestingly, there is a strong cytosolic component in the SIRT1 expression pattern. We further characterized SIRT1 in p53‐wild‐type and ‐mutant cell lines and show that SIRT1 mRNA‐knockdown leads to a p53‐independent decrease of cell proliferation and induction of apoptosis. In addition, SIRT1 expression has been found to be inducible upon DNA damage. A previously discovered small molecule SIRT1 inhibitor with nanomolar in vitro activity has been tested in cancer relevant assays. The SIRT1 inhibitory compound showed no potent anti‐proliferative activity despite hitting its molecular target within tumor cells. From these studies we conclude that it may not be sufficient to block the catalytic function of SIRT1, and that its survival effects may be mainly brought about by means other then the deacetylase function. The increased cytosolic expression of SIRT1 in cancer cells could be an indicator of such novel functions.
Biosynthesis of 5‐deoxyflavanones in microorganisms
Authors: Yan Yajun , Huang Lixuan , Koffas Mattheos A. G. 
Published: September 2007

AbstractFlavanones are the common precursors of plant polyphenolic compounds collectively known as flavonoids. Leguminous plants have evolved a distinct class of flavanone molecules, known as 5‐deoxyflavanones that play important roles in their symbiotic interactions. A four‐step metabolic circuit was constructed inEscherichia coliwith plant genes from heterologous origins: 4‐coumarate:coenzyme A ligase fromPetroselinum crispum, chalcone synthases (CHS) fromMedicago sativaandPetunia x hybridaand chalcone reductase and chalcone isomerase fromM. sativa.Evaluation of the different recombinant strains in shake flask experiments demonstrated thatP. hybridarather thanM. sativaCHS resulted in the highest liquiritigenin production levels in glucose minimal medium, starting from precursorp‐coumaric acid. Expression of the same recombinant pathway inSaccharomyces cerevisiaeresulted in the accumulation of both 5‐hydroxyflavanone and 5‐deoxyflavanone, with the yields of the later lower than that achieved inE. coli.Other phenylpropanoid acid precursors, such as cinnamic acid and caffeic acid could also be metabolized through the recombinant pathway, yielding corresponding 5‐deoxyflavanone compounds. The construction of such recombinant strains for 5‐deoxyflavanone biosynthesis offers an alternative way to biochemically characterize flavonoid biosynthetic enzymes and promising production platforms for the biosynthesis of such high‐value natural products.
Protonation free energy levels in complex molecular systems
Authors: Antosiewicz Jan M. 
Published: September 2007

AbstractAll proteins, nucleic acids, and other biomolecules contain residues capable of exchanging protons with their environment. These proton transfer phenomena lead to pH sensitivity of many molecular processes underlying biological phenomena. In the course of biological evolution, Nature has invented some mechanisms to use pH gradients to regulate biomolecular processes inside cells or in interstitial fluids. Therefore, an ability to model protonation equilibria in molecular systems accurately would be of enormous value for our understanding of biological processes and for possible rational influence on them, like in developing pH dependent drugs to treat particular diseases. This work presents a derivation, by thermodynamic and statistical mechanical methods, of an expression for the free energy of a complex molecular system at arbitrary ionization state of its titratable residues. This constitutes one of the elements of modeling protonation equilibria. Starting from a consideration of a simple acid–base equilibrium of a model compound with a single tritratable group, we arrive at an expression which is of general validity for complex systems. The only approximation used in this derivation is the postulating that the interaction energy between any pair of titratable sites does not depend on the protonation states of all the remaining ionizable groups. © 2007 Wiley Periodicals, Inc. Biopolymers 89: 262–269, 2008.This article was originally published online as an accepted preprint. The “Published Online” date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com
Cα‐Methyl proline: A unique example of split personality
Authors: Moretto Alessandro , Terrenzani Francesco , Crisma Marco , Formaggio Fernando , Kaptein Bernard , Broxterman Quirinus B. , Toniolo Claudio 
Published: September 2007

AbstractMethylation at the Cα‐position of a Pro residue was expected to lock the preceding tertiary amide (ω) torsion angle of the resulting (αMe)Pro to the trans disposition and to restrict the ϕ,ψ surface to the single region where the 310/α‐helices are found (in this five‐membered ring residue ϕ is severely constrained to about ±65° by its cyclic nature). The results of the present X‐ray diffraction work on a selected set of four Nα‐blocked, (αMe)Pro‐containing, dipeptide N′‐alkylamides clearly show that, although the region of the conformational map largely preferred by (αMe)Pro would indeed be that typical of 310/α‐helices, the semi‐extended [type‐II poly(Pro)n helix] region can also be explored by this extremely sterically demanding Cα‐tetrasubstituted α‐amino acid. In addition, the known high propensity for β‐turn formation of the Pro residue is further enhanced in peptides based on its Cα‐methylated derivative. © 2007 Wiley Periodicals, Inc. Biopolymers 89: 465–470, 2008.This article was originally published online as an accepted preprint. The “Published Online” date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com
Stabilization of the N‐terminal β‐hairpin of ubiquitin by a terminal hydrophobic cluster
Authors: Riemen Alex J. , Waters Marcey L. 
Published: September 2007

AbstractStudy of model β‐hairpin peptides allows for better understanding of the factors involved in the formation of β‐sheet secondary structure in proteins. It is known that turn sequence, sidechain–sidechain interactions, interstrand hydrogen bonding, and β‐sheet propensity of residues are all important for β‐hairpin stability in aqueous solution. However, interactions of the sidechains of the terminal residues of hairpins are thought to contribute little to overall hairpin stability since these residues are typically frayed. Here, the authors report a stabilizing hydrophobic cluster of residues at the termini of the naturally occurring excised N‐terminal β‐hairpin of Ubiquitin that folds autonomously in aqueous solution. Our data show that deletion of Met1 and Val17 from this hairpin destabilized the folded state in both aqueous solution and in aqueous‐methanol solutions. These results suggest that interactions of terminal residues which are usually frayed can nonetheless contribute significantly to overall stability of β‐hairpin. © 2007 Wiley Periodicals, Inc. Biopolymers (Pept Sci) 90: 394–398, 2008.This article was originally published online as an accepted preprint. The “Published Online” date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com
Participation in research program
Authors: Zhou Xuanwei , Lin Juan , Yin Yizhou , Sun Xiaofen , Tang Kexuan 
Published: September 2007

AbstractA novel course, “Participation in Research Program (PRP)” in life sciences is open for 1st to 3rd year undergraduates. PRP introduces the principles of a variety of biological methods and techniques and also offers an opportunity to explore some specific knowledge in more detail prior to thesis research. In addition, the PRP introduces some methodologies that have been proven to be successful at each institution to participants. Through disciplines crossing, students were trained theoretically and practically about modern techniques, facilitating the efficient commutation of general laboratory skills and modern laboratory skills, and the possession of higher research ability. Therefore, during some basic training (e.g., usage and maintenance of equipments, designing and completing experiments, analyzing data and reporting results, etc.), a series of capabilities are strengthened, such as basic experimental skills, searching appropriate methods, explaining unknown biological phenomena, and the capacity of solving problems. To determine the efficiency of these strategies, we carefully examined students' performance and demonstrated the progress in students' basic abilities of scientific research in their training.
Isolation of RNA and RT‐PCR, cloning, and sequencing of noncoding RNAs from fungi*
Authors: Luo Yuping , Gong Xi , Xu Ling , Li Siguang 
Published: September 2007

AbstractRNomics, the understanding of functional RNAs and their interactions at a genomic level, is of utmost practical and theoretical importance in modern life sciences. To introduce our students to the techniques and promise of this emerging field, a practical class activity for advanced undergraduate students in biochemistry and molecular biology is described. In these exercises, students first identify noncoding RNA from different fungi by computational methods and analyze their transcription regulation signals and splice signals by bioinformatics tools, then isolate total RNA from these fungi, and finally verify these noncoding RNA gene expressions by reverse transcriptase‐polymerase chain reaction, cloning, and sequencing. This activity not only introduces students to the concept of RNomics, noncoding RNA, and RNA splicing, but also introduces students to the practice of basic molecular techniques. The natural combination of the genome projects and bioinformatics with modern molecular biology techniques is considered a major advantage of this laboratory course.
Engaging the learner: Embedding information literacy skills into a biotechnology degree
Authors: Ward Helena , Hockey Julie 
Published: September 2007

AbstractOne of the challenges of the Biotechnology industry is keeping up to date with the rapid pace of change and that much of the information, which students learn in their undergraduate studies, will be out of date in a few years. It is therefore crucial that Biotechnology students have the skills to access the relevant information for their studies and critically evaluate the vast volume of information and its sources. By developing information literacy skills, which are part of lifelong learning, Biotechnology graduates are better prepared for their careers. Students also need to understand the issues related to the use of information such as social, political, ethical, and legal implications. This paper will outline the embedding of information literacy skills within the Biotechnology degree at the University of South Australia. Examples of specific activities and their link to assessment will be discussed.
Improving Thai students' understanding of concepts in protein purification by using Thai and English versions of a simulation program*
Authors: Phornphisutthimas Somkiat , Panijpan Bhinyo , Wood Edward J. , Booth Andrew G. 
Published: September 2007

AbstractTo support student learning in biochemistry and related courses, a simulation program, the Protein Purification Program, offers an alternative multimedia‐based tool. This program has now been translated to produce a Thai version. However, translation from the original into the Thai language is limited by the differences between the language characteristics of English and Thai. Therefore, use of the program with Thai students had a twofold purpose. It helped their understanding of the concepts of protein purification by allowing code switching between the languages, but it also improved their understanding of, and competence in scientific English, which is a vital skill for functioning as a modern biochemist. According to the results of the questionnaires, undergraduates using the Thai/English program scored significantly higher than those using only the English language program (p < 0.05). In addition, the interview data suggested that the Thai/English program had improved student understanding of the concepts of protein purification to a greater extent than a single language (English) program. Students' overall preference in terms of their learning using the Thai/English program was 4.15 on a 1–5 Likert scale.
Why the linkage of glycogen to glycogenin was so difficult to determine
Authors: Whelan William J. 
Published: September 2007

AbstractGlycogenin is the self‐glucosylating enzyme that primes mammalian and yeast glycogen synthesis. It proved to be the long‐suspected, covalently bound protein component of glycogen. One of the most difficult aspects in elucidating the role of glycogenin was to learn the nature of its covalent bond to glycogen.
Hydrogenation of the Ce(Rh1‐xIrx)Ga System: Occurrence of Antiferromagnetic Ordering in the Hydrides Ce(Rh1‐xIrx)GaH1.8.
Authors: Chevalier B. , Heying B. , Rodewald U. Ch. , Sebastian C. Peter , Bauer E. , Poettgen R. 
Published: September 2007

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.