bluuebunny/crossref_metadata_2025_split huggingface dataset:
Analysis of individual‐ and school‐level clustering of power frequency magnetic fields
Authors: Lin I‐Fan , Li Chung‐Yi , Wang Jung‐Der 
Published: June 2008

AbstractThis study reports the continuous 8‐h monitoring of data on extremely low‐frequency magnetic fields (ELF‐MF) relating to 14 children and 35 teachers in 11 elementary schools in Northern Taiwan. It was anticipated that the subjects in two of these campuses would have elevated exposure to ELF‐MF as a result of their close proximity to high‐voltage (161 kilo‐Volt, kV) power lines. The results of our analysis reveal that in those schools with high‐voltage power lines running through the campuses, the mean ELF‐MF exposure level (0.38 ± 0.51 micro‐Tesla (µT), or 0.15, 0.25 and 0.44 µT at the respective 25th, 50th and 75th percentiles) was higher than the mean ELF‐MF exposure level for campuses situated far away from such high‐voltage power lines (0.14 ± 0.27 µT, or 0.04, 0.06 and 0.10 µT at the respective 25th, 50th and 75th percentiles). The multi‐level analytical technique, which takes individual measurements as the analytical unit, and which also takes into consideration the inter‐correlation between measurements from the same individual and/or campus, was also applied to the analysis of the data. We conclude that individual‐level and school‐level clustering of the measurements, both of which were discernible in this study, should be taken into consideration in any future analysis of data obtained from the continuous monitoring of exposure to ELF‐MF. Bioelectromagnetics 29:564–570, 2008. © 2008 Wiley‐Liss, Inc.
Structure, biological activity, and enzymatic transformation of fucoidans from the brown seaweeds
Authors: Kusaykin Mikhail , Bakunina Irina , Sova Victoria , Ermakova Svetlana , Kuznetsova Tatyana , Besednova Natalya , Zaporozhets Tatyana , Zvyagintseva Tatyana 
Published: June 2008

AbstractRecent advances in the study of fucoidans, biologically active sulfated α‐L‐fucans of diverse structures and synthesized exclusively by marine organisms, are overviewed. Their structure, biological activity, the products of their enzymatic degradation and the different enzymes of degradation and modification are considered.
Development and application of an automated, low‐volume chromatography system for resin and condition screening
Authors: Teeters Mark , Bezila Daniel , Alred Patricia , Velayudhan Ajoy 
Published: June 2008

AbstractA small‐volume chromatography system was developed for rapid resin and parameter screening and applied to the purification of a therapeutic monoclonal antibody from a key product‐related impurity. Accounting for constraints in peripheral volume, gradient formation, column integrity, and fraction collection in microtiter plates, the resulting system employed 2‐mL columns and was successfully integrated with plate‐based methods for rapid sample analysis (e. g., use of automated liquid handlers, plate readers, and HPLC). Several cation‐exchange chromatography resins were screened using automated programs and tailored gradients for the combination of a particular resin and a given antibody feedstock produced during Phase 1 development. Results from the tailored gradient runs were used to select a resin, and to arrive at efficient stepwise elution schedules for the chosen resin. By maintaining a constant residence time, final operating parameters were successfully scaled to representative bed heights and column diameters up to 2.6 cm (106 mL). This approach significantly improved throughput while reducing development time and material consumption.
Direct plant gene delivery with a poly(amidoamine) dendrimer
Authors: Pasupathy Karthikeyan , Lin Sijie , Hu Qian , Luo Hong , Ke Pu Chun 
Published: June 2008

AbstractPlant gene delivery is challenging due to the presence of plant cell walls. Conventional means such as Agrobacterium infection, biolistic particle bombardment, electroporation, or polyethylene glycol attachment are often characterized by high cost, labor extensiveness, and a significant perturbation to the growth of cells. We have succeeded in delivering GFP‐encoding plasmid DNA to turfgrass cells using poly(amidoamine) dendrimers. Our new scheme utilizes the physiochemical properties as well as the nanosize of the poly(amidoamine) dendrimer for direct and noninvasive gene delivery. The GFP gene was expressed in the plant cells as observed by confocal fluorescence microscopy. The transfection efficiency may be further improved by optimizing the pH of the cell culture medium and the molar ratio of the dendrimer to DNA. The use of the current delivery system can be extended to virtually all plant species having successful regeneration systems in place.
Protozoan biomass relation to nutrient and chemical oxygen demand removal in activated sludge mixed liquor
Authors: Akpor Oghenerobor B. , Momba Maggy N. B. , Okonkwo Jonathan O. 
Published: June 2008

AbstractThe relationship between biomass concentration to nutrient and chemical oxygen demand (COD) removal in mixed liquor supplemented with sodium acetate was investigated, using three protozoan isolates and three different initial biomass concentrations (101, 102 and 103 cells/mL). The study was carried out in a shaking flask environment at a shaking speed of 100 rpm for 96 h at 25°C. Aliquot samples were taken periodically for the determination of phosphate, nitrate, COD and dissolved oxygen, using standard methods. The results revealed remarkable phosphate removal of 82–95% at biomass concentration of 103cells/mL. A high nitrate removal of over 87% was observed at all initial biomass concentration in mixed liquor. There was an observed COD increase of over 50% in mixed liquor in at the end of 96‐h incubation and this was irrespective of initial biomass concentration used for inoculation. The study shows the trend in nutrient and COD removal at different biomass concentrations of the test isolates in mixed liquor.
Exploitation of biological wastes for the production of value‐added products under solid‐state fermentation conditions
Authors: Rodríguez Couto Susana 
Published: June 2008

AbstractBiological wastes contain several reusable substances of high value such as soluble sugars and fibre. Direct disposal of such wastes to soil or landfill causes serious environmental problems. Thus, the development of potential value‐added processes for these wastes is highly attractive. These biological wastes can be used as support‐substrates in solid‐state fermentation (SSF) to produce industrially relevant metabolites with great economical advantage. In addition, it is an environmentfriendly method of waste management. This paper reviews the reutilisation of biological wastes for the production of value‐added products using the SSF technique.
Expression of recombinant Hirudin in transgenic mice milk driven by the goat β‐casein promoter
Authors: Yen Chon‐Ho , Yang Chi‐Kai , Chen I‐Chung , Lin Yin‐Shen , Lin Chih‐Sheng , Chu Sen , Tu Ching‐Fu 
Published: June 2008

AbstractHirudin, isolated from the leechHirudo medicinalis,inhibits thrombin directly and several expression systems have been used to produce recombinant Hirudin (rHirudin) for pharmaceutical purposes. A DNA fragment containing the Hirudin coding sequence and goat β‐casein secretion signal was chemically synthesized in this study. The synthetic DNA then was further constructed into a goat β‐casein expression vector for mouse transgenesis. Four lines of transgenic mice were successfully developed and one line showed a meaningful anti‐thrombin activity of 40,000 anti‐thrombin units (ATU)/mL in their milk. In this animal line, Hirudin mRNA was found in samples of uterus and kidney with insignificant anti‐thrombin activity (≤ 280 ATU/g wet tissue); however, mammary glands showed a higher activity of 780 ATU/g wet tissue. Transgenic mice showed no evident physical abnormality. The purified rHirudin was further analyzed by amino acid analysis and was found to contain a tyrosineO‐sulfate residue that is absent in rHirudin expression either throughEscherichia colior yeast host systems. Experimental results demonstrated that the β‐casein‐promoted Hirudin transgene could be successfully expressed in a murine model and may be applicable to large mammals such as livestock for mass production of rHirudin for pharmaceuticals.
Fermentative butanol production by clostridia
Authors: Lee Sang Yup , Park Jin Hwan , Jang Seh Hee , Nielsen Lars K. , Kim Jaehyun , Jung Kwang S. 
Published: June 2008

AbstractButanol is an aliphatic saturated alcohol having the molecular formula of C4H9OH. Butanol can be used as an intermediate in chemical synthesis and as a solvent for a wide variety of chemical and textile industry applications. Moreover, butanol has been considered as a potential fuel or fuel additive. Biological production of butanol (with acetone and ethanol) was one of the largest industrial fermentation processes early in the 20th century. However, fermentative production of butanol had lost its competitiveness by 1960s due to increasing substrate costs and the advent of more efficient petrochemical processes. Recently, increasing demand for the use of renewable resources as feedstock for the production of chemicals combined with advances in biotechnology through omics, systems biology, metabolic engineering and innovative process developments is generating a renewed interest in fermentative butanol production. This article reviews biotechnological production of butanol by clostridia and some relevant fermentation and downstream processes. The strategies for strain improvement by metabolic engineering and further requirements to make fermentative butanol production a successful industrial process are also discussed. Biotechnol. Bioeng. 2008;101: 209–228. © 2008 Wiley Periodicals, Inc.
Thermodynamic Analysis of Nylon Nucleic Acids
Authors: Liu Yu , Wang Risheng , Ding Liang , Sha Ruojie , Lukeman Philip S. , Canary James W. , Seeman Nadrian C. 
Published: June 2008

AbstractThe stability and structure of nylon nucleic acid duplexes with complementary DNA and RNA strands was examined. Thermal denaturing studies of a series of oligonucleotides that contained nylon nucleic acids (1–5 amide linkages) revealed that the amide linkage significantly enhanced the binding affinity of nylon nucleic acids towards both complementary DNA (up to 26 °C increase in the thermal transition temperature (Tm) for five linkages) and RNA (around 15 °C increase in Tm for five linkages) compared with nonamide linked precursor strands. For both DNA and RNA complements, increasing derivatization decreased the melting temperatures of uncoupled molecules relative to unmodified strands; by contrast, increasing lengths of coupled copolymer raised Tm from less to slightly greater than Tm of unmodified strands. Thermodynamic data extracted from melting curves and CD spectra of nylon nucleic acid duplexes were consistent with loss of stability due to incorporation of pendent groups on the 2′‐position of ribose and recovery of stability upon linkage of the side chains.
Mesoporous Silicas by Self‐Assembly of Lipid Molecules: Ribbon, Hollow Sphere, and Chiral Materials
Authors: Jin Haiying , Qiu Huibin , Sakamoto Yasuhiro , Shu Peng , Terasaki Osamu , Che Shunai 
Published: June 2008

AbstractUsing lipids (N‐acyl amino acids) and 3‐aminopropyltriethoxysilane as structure‐ and co‐structure‐directing agents, mesoporous silicas with four different morphologies, that is, helical ribbon (HR), hollow sphere, circular disk, and helical hexagonal rod, were synthesized just by changing the synthesis temperature from 0 °C to 10, 15, or 20 °C. The structures were studied by electron microscopy. It was found that 1) the structures have double‐layer disordered mesopores in the HR, radially oriented mesopores in the hollow sphere, and highly ordered straight and chiral 2D‐hexagonal mesopores in the disklike structure and helical rod, respectively; 2) these four types of mesoporous silica were transformed from the flat bilayered lipid ribbon with a chain‐interdigitated layer phase through a solid–solid transformation for HR formation and a dissolving procedure transformation for the synthesis of the hollow sphere, circular disk, and twisted morphologies; 3) the mesoporous silica helical ribbon was exclusively right‐handed and the 2D‐hexagonal chiral mesoporous silica was excessively left‐handed when the L‐form N‐acyl amino acid was used as the lipid template; 4) the HR was formed only by the chiral lipid molecules, whereas the 2D‐hexagonal chiral mesoporous silicas were formed by chiral, achiral, and racemic lipids. Our findings give important information for the understanding of the formation of chiral materials at the molecular level and will facilitate a more efficient and systematic approach to the generation of rationalized chiral libraries.
Novel Biodegradable Adaptive Hydrogels: Controlled Synthesis and Full Characterization of the Amphiphilic Co‐Networks
Authors: Mespouille Laetitia , Coulembier Olivier , Paneva Dilyana , Degée Philippe , Rashkov Iliya , Dubois Philippe 
Published: June 2008

AbstractAdaptive and amphiphilic poly(N,N‐dimethylamino‐2‐ethyl methacrylate‐graft‐poly[ε‐caprolactone]) co‐networks (netP(DMAEMA‐g‐PCL)) were synthesized from a combination of controlled polymerization techniques. Firstly, PCL cross‐linkers were produced by ring‐opening polymerization (ROP) of ε‐CL initiated by 1,4‐butane‐diol and catalyzed by tin(II) 2‐ethylhexanoate ([Sn(Oct)2]), followed by the quantitative esterification reaction of terminal hydroxyl end‐groups with methacrylic anhydride. Then, PCL cross‐linkers were copolymerized to DMAEMA monomers by atom‐transfer radical polymerization (ATRP) in THF at 60 °C using CuBr complexed by 1,1,4,7,10,10‐hexamethyltriethylenetetramine (HMTETA) and 2‐ethyl isobutyrylbromide (EiBBr) as catalytic complex and initiator, respectively. A comprehensive study of gel formation was carried out by employing dynamic light scattering (DLS) to determine the gel point as a function of several parameters and to characterize the viscous solutions obtained before the gel point was reached. The evolution of the mean diameters was compared to a model previously developed by Fukuda and these attest to the living formation of the polymer co‐network. Furthermore, we also demonstrated the reliability of ATRP for producing well‐defined and homogeneous polymer co‐networks by the smaller deviation from Flory's theory in terms of cross‐linking density. For sake of clarity, the impact of polymerization techniques over the final structure and, therefore, properties was highlighted by comparing two samples of similar composition, but that were produced by either ATRP or thermal‐initiated free‐radical polymerization (FRP).
Two‐Component Hydrogels Comprising Fatty Acids and Amines: Structure, Properties, and Application as a Template for the Synthesis of Metal Nanoparticles
Authors: Basit Hajra , Pal Asish , Sen Saikat , Bhattacharya Santanu 
Published: June 2008

AbstractStearic acid or eicosanoic acid mixed with di‐ or oligomeric amines in specific molar ratios form stable gels in water. The formation of such hydrogels depends on the hydrophobicity of the fatty acid, and also on the type of amine used. The gelation properties of these two‐component systems were investigated using electron microscopy, FTIR spectroscopy, 1H NMR spectroscopy, differential scanning calorimetry (DSC), and both single‐crystal and cast‐film X‐ray diffraction. Results of FTIR spectral analysis suggest salt formation during gelation. 1H NMR analysis of the gels indicates that the fatty acid chains are immobilized in the gel state and when the gel melts, these chains regain their mobility. Analysis of DSC data indicates that increase in the spacer length in the di‐/oligomeric amine lowers the gel‐melting temperature. Two of these gelator salts developed into crystals and structural details of such systems could be secured by single‐crystal X‐ray diffraction analysis. The structural information of the salts thus obtained was compared with the XRD data of the self‐supporting films of those gels. Such analyses provided pertinent structural insight into the supramolecular interactions that prevail within these gelator assemblies. Analysis of the crystal structure confirmed that multilayered lamellar aggregates exist in the gel and it also showed that the three‐dimensional ordering observed in the crystalline phase is retained in only one direction in the gel state. Finally, the hydrogel was used as a medium for the synthesis of silver nanoparticles. The nanoparticles were found to position themselves on the fibers and produced a long, ordered assembly of gel–nanoparticle composite.
Definition of Magneto‐Structural Correlations for the MnII Ion
Authors: Duboc Carole , Collomb Marie‐Noëlle , Pécaut Jacques , Deronzier Alain , Neese Frank 
Published: June 2008

AbstractThe electronic properties of the high spin mononuclear MnII complexes [Mn(tpa)(NCS)2] (1) (tpa=tris‐2‐picolylamine), [Mn(tBu3‐terpy)2](PF6)2 (2) (tBu3‐terpy=4,4′,4′′‐tri‐tert‐butyl‐2,2′:6′,2′′‐terpyridine) and [Mn(terpy)2](I)2 (3) (terpy=2,2′:6′,2′′‐terpyridine) with an N6 coordination sphere have been determined by multifrequency EPR spectroscopy. The X‐ray structures of 1⋅CH3CN and 2⋅C4H10O⋅0.5 C2H5OH⋅0.5 CH3OH reveal that the MnII ion lies at the center of a distorted octahedron. The D‐values of 1–3 all fall in the narrow range of 0.041 to 0.105 cm−1. The comparison of the results reported here and those found in the literature is consistent with the following observation: the D value is sensitive to the coordination number (6 or 5) of the MnII ion as long as the coordination sphere involves only nitrogen and/or oxygen based ligands. This magneto‐structural correlation has been analyzed in this work though DFT model calculations. The zero‐field splitting (zfs) parameters of 1–3 have been calculated and are in reasonable agreement with the experimental values. Hypothetical simplified models [Mn(NH3)x(OH2)y]2+ (x+y=5 or 6 and [Mn(NH3)5X]+ (X=OH, Cl)) have been constructed to investigate the origin of the zfs. This investigation reveals i) that D is sensitive to the coordination number (5 or 6) of the MnII ion, ii) for the five coordinate systems the major contribution to D is the spin‐orbit coupling part, iii) for the six coordinate systems the major contribution to D is the spin–spin interaction and iv) the deprotonation of a water ligand leads to an increase of D, consistent with the relative ligand fields of OH− versus H2O.
New Reactions of a Dibenzo[a,e]pentalene
Authors: Saito Masaichi , Nakamura Michio , Tajima Tomoyuki 
Published: June 2008

AbstractReduction of dibenzo[a,e]pentalene 3 (denoted as dibenzopentalene hereafter) with excess lithium gave dilithium dibenzopentalenide 1. Since oxidation of 1 with iodine gave 3, redox behavior between 1 and 3 is controllable and reversible. Reaction of 3 with methyllithium gave lithium 5‐methyldibenzopentalenide 5, the formation of which was evidenced by some trapping experiments and X‐ray crystallographic analysis. Reactions of 3 with halogens gave 5,10‐dihalodibenzopentalenes, 8 and 9. Some optical properties of novel dibenzopentalene derivatives are also demonstrated.
Anionic Cross‐Coupling Reaction of α‐Metallated Alkenyl Sulfoximines and Alkenyl Sulfoximines with Cuprates Featuring a 1,2‐Metal‐Ate Rearrangement of Sulfoximine‐Substituted Higher Order Alkenyl Cuprates and an α‐Metallation of Alkenyl Sulfoximines by Cuprates
Authors: Gais Hans‐Joachim , Rao C. Venkateshwar , Loo Ralf 
Published: June 2008

Abstract(E)‐ and (Z)‐configured α‐lithioalkenyl sulfoximines, which are available through lithiation of the corresponding alkenyl sulfoximines, undergo a anionic cross‐coupling reaction (ACCR) with organocuprates with formation of the corresponding alkenyl cuprates and sulfinamide. The alkenyl cuprates can be trapped by electrophiles. The ACCR presumably proceeds via the formation of a higher‐order sulfoximine‐substituted alkenyl cuprate, which undergoes a 1,2‐metal‐ate rearrangement whereby the sulfoximine group acts as the nucleofuge. The parent (E)‐ and (Z)‐configured alkenyl sulfoximines suffer upon treatment with an organocuprate a deprotonation at the α‐position with formation of the corresponding α‐cuprioalkenyl sulfoximines. These derivatives also enter into a similar ACCR with organocuprates. The ACCR of sulfoximines substituted homoallylic alcohols allows a stereoselective access to enantio‐ and diastereopure substituted homoallylic alcohols.
Dendrimers and DNA: Combinations of Two Special Topologies for Nanomaterials and Biology
Authors: Caminade Anne‐Marie , Turrin Cédric‐Olivier , Majoral Jean‐Pierre 
Published: June 2008

AbstractInteractions between two precisely defined three‐dimensional architectures (DNA and dendrimers) are described. Highly synergetic effects occur, as illustrated in two cases: dendrimers can be used as three‐dimensional linkers for oligonucleotides, affording highly sensitive microarrays (biochips), and positively charged dendrimers strongly interact with DNA, allowing penetration inside cells (genetic transfection).
Intramolecular Sensitization of Photocleavage of the Photolabile 2‐(2‐Nitrophenyl)propoxycarbonyl (NPPOC) Protecting Group: Photoproducts and Photokinetics of the Release of Nucleosides
Authors: Wöll Dominik , Smirnova Julia , Galetskaya Marina , Prykota Tamara , Bühler Jochen , Stengele Klaus‐Peter , Pfleiderer Wolfgang , Steiner Ulrich E. 
Published: June 2008

AbstractNovel photolabile protecting groups based on the 2‐(2‐nitrophenyl)propoxycarbonyl (NPPOC) group with a covalently linked thioxanthone as an intramolecular triplet sensitizer exhibit significantly enhanced light sensitivity under continuous illumination. Herein we present a detailed study of the photokinetics and photoproducts of nucleosides caged with these new protecting groups. Relative to the parent NPPOC group, the light sensitivity of the new photolabile protecting groups is enhanced by up to a factor of 21 at 366 nm and is still quite high at 405 nm, the wavelength at which the sensitivity of the parent compound is practically zero. A new pathway for deprotection of the NPPOC group proceeding through a nitroso benzylalcohol intermediate has been discovered to complement the main mechanism, which involves β elimination. Under standard conditions of lithographic DNA‐chip synthesis, some of the new compounds, while maintaining the same chip quality, react ten times faster than the unmodified NPPOC‐protected nucleosides.