bluuebunny/crossref_metadata_2025_split huggingface dataset:
3T3 cell motility and morphology before, during, and after exposure to extremely‐low‐frequency magnetic fields
Authors: Spadinger Ingrid , Agnew David , Palcic Branko 
Published: February 2006

AbstractAutomated image cytometry techniques were used to measure motility and morphology in 3T3 fibro‐blasts exposed to extremely‐low‐frequency (ELF) magnetic fields. Cell motility and morphology were measured as a function of time before, during, and after 3–4 hour exposures to vertically oriented, 100 μTRMS sinusoidal magnetic fields at various frequencies in the 10–63 Hz range. Sham exposures were also carried out. No static DC fields were applied, but the geomagnetic field was almost vertical and, therefore, had a large component (28.3 μT) parallel to the applied AC field. The morphology and motile behavior of the cells were characterized by mathematically defined descriptors, which were calculated and averaged for the exposure period as well as for control periods that preceded and followed the exposure period. Each experiment involved the tracking of 100 cells that were subjected to one of the test frequencies (unless a sham exposure was being conducted). Statistical analysis of the results showed that even small changes of 10–20% could be significant at the P <.05 level. Changes on this order were measured in a significant proportion of the experiments. However, because such results were seen for both the sham‐exposed and the ELF‐exposed cells, and because the range of values that was obtained for the sham exposures was the same as that obtained for the ELF exposures, we concluded that there was no evidence to show that any of the measured changes were attributable to the applied ELF magnetic field. © 1995 Wiley‐Liss, Inc.
Microwave influence on the isolated heart function: II. Combined effect of radiation and some drugs
Authors: Pakhomov Andrei G. , Dubovick Boris V. , Degtyariov Igor G. , Pronkevich Anatoly N. 
Published: February 2006

AbstractThe combined effects of microwave radiation and some drugs were studied in an isolated frog auricle preparation. The experiments established that exposure to pulse‐modulated 915 MHz microwaves for up to 40 min had no effect on either the rate or the amplitude of spontaneous auricle twitches, unless the average absorbed power was high enough to produce preparation heating. Treatment of the preparation with saline containing (0.6–3.0) 10−5 M of propranolol or (0.5–1.5) 10−7 M of atropine altered neither its pacemaker nor its contractile functions; these drugs also had no effect when they were combined with nonthermal microwave irradiation. Caffeine (1 mM) strongly increased the average heart power, which was calculated as the product of twitch rate and amplitude. The caffeine effect appeared to be significantly augmented (by about 15%, P<0.02) under exposure to burst‐type pulsed microwaves (pulse width, 1.5 msec; pause, 2.5 msec; 8 pulses/burst, 16 bursts/s; average SAR, 8–10 W/kg). By itself, this modulation was not effective; the heating of the preparation and saline during exposure was approximately 0.1°C, which could not account for the detected changes. The experimental results demonstrate that caffeine treatment increases the microwave sensitivity of the frog auricle preparation and reveals primarily subthreshold, nonthermal microwave effect. © 1995 Wiley‐Liss, Inc.
Spectral analysis of magnetic fields from domestic appliances and corresponding induced current densities in an anatomically based model of the human head
Authors: Tofani Santi , Anglesio Laura , Ossola Piero , d'Amore Giovanni 
Published: February 2006

AbstractMagnetic fields emitted by electric appliances such as razors, hair dryers, and drills were measured in the frequency domain. Results show the presence of high‐frequency components (up to 96 kHz for razors, up to 3.4 kHz for hair dryers, and up to 8.6 kHz for drills) in the harmonic content of the fields. The measured fields were used to calculate the induced current densities in an anatomically based model of the human head (resolution 1.31 cm) by using the impedance method. The harmonic field contribution to the current density was higher than that from the carrier frequency for all the tested appliances. © 1995 Wiley‐Liss, Inc.
Residential exposure to magnetic fields generated by 110‐400 kV power lines in Finland
Authors: Valjus Jorma , Hongisto Mikko , Verkasalo Pia , Järvinen Pekka , Heikkilä Kauko , Koskenvuo Markku 
Published: February 2006

AbstractIn a specific case, the magnetic field generated in a building by a nearby power line is usually easy to calculate, although the accuracy of these calculations is sensitive to the quality of source information. To be able to study public health dimensions of magnetic field exposure (e.g., risk of cancer), it is necessary to evaluate the size and exposure of the population at risk. Relatively little quantitative information on public exposure to power‐frequency magnetic fields of high‐voltage power lines is available. This report describes residential exposure to magnetic fields from 110 kV, 220 kV, and 400 kV power lines in Finland at the national level, including 90% of the total line length in 1989. A geographical information system (GIS) was used to identify the buildings located near the power lines. After determining the distances between the lines and the buildings, historical data on load currents of these lines were used to calculate the magnetic fields. The residential magnetic field histories were then linked to the residents by means of a computerized central population register. The data obtained on personal exposure have also been utilized in a nationwide epidemiological study on magnetic field exposure of power lines and risk of cancer. The methods of exposure assessment and results of the number of buildings near 110 kV, 220 kV, and 400 kV power lines, their average annual magnetic fields, and personal exposure to magnetic fields from these lines are described. We found that 15,600 residents lived in an average residential magnetic field ≥0.1 μT caused by power lines in 1989. The number of these residents increased fivefold during 1970‐1989. We estimated that 0.3% of the population was exposed in their residences to an annual average magnetic flux density from 110 kV, 220 kV, and 400 kV power lines higher than 0.1 μT, the level that the background magnetic flux density in general does not exceed in Finnish homes. Thus, the problem of magnetic field exposure generated by high‐voltage lines concerns only a relatively small fraction of the total population in Finland. However, the size and exposure of the population at risk remain somewhat arbitrary in practical multisource situations, as the biological interaction mechanism, the concept of harmful dose, and, in particular, the significance of the duration of exposure are unknown. © 1995 Wiley‐Liss, Inc.
Designing EMF experiments: What is required to characterize “exposure”?
Authors: Valberg Peter A. 
Published: February 2006

AbstractAnyone who has attempted to organize and synthesize the results of research on biological effects of electric and magnetic fields (EMF) has experienced frustration when trying to evaluate the comparability of EMF exposures among separate studies. Reporting of exposure characteristics is often incomplete, and some investigators focus on particular nuances of exposure, which in other laboratories go unrecorded because they are not regarded as important. The obstacles encountered when comparing studies, when designing replication studies, and when evaluating research proposals could be reduced were a more standardized approach taken in describing “EMF exposure.” To this end, a numerical listing of 18 separate parameters important to EMF exposure characterization is proposed. Although the goal of this list is primarily to expedite the description of EMF exposure, references are provided to examples of EMF exposures and to detailed discussions of EMF exposure systems. © 1995 Wiley‐Liss, Inc.
Review: Selective ligand‐exchange adsorbents prepared by template polymerization
Authors: Vidyasankar Sundaresan , Dhal Pradeep K. , Plunkett Sean D. , Arnold Frances H. 
Published: February 2006

AbstractHighly selective ligand‐exchange absorbents have been prepared by template polymerization, a process in which the target molecule serves as a template for assembly of specific recognition sites. In an effort to develop materials suitable for chromatographic separations, thin coatings of the selctive templated polymers have been grafted to two reactive macroporous supports, poly(trimethylolpropane trimethacrylate) (TRIM), and propylmethacrylate‐derivatized silica beads. The precursor polymer prepared from the trifunctioal TRIM monomer is macroporous and highly crosslinked, providing a stable structure for surface grafting. The TRIM precursor polymer and various surface‐grafted copolymers have been characterized by scanning electron microscopy (SEM) and IR, 13C NMR, and XPS spectroscopic techniques. Composite adsorbents have also been prepared using propylmethacrylate‐modified silica particles. While equilibrium rebinding selectivites for both types of surface‐templated materials are similar to those reported previously for bulk‐polymerized template polymers, the composite materials are far better suited to chromatographic separatios. Highly similar bis‐imidazole substrates can be separated by ligand‐exchange chromatography on these new templated adsorbents. © 1995 John Wiley & Sons, Inc.
Protected amino acids as novel low‐molecular‐weight displacers in cation‐exchange displacement chromatography
Authors: Kundu Amitava , Vunnum Suresh , Jayaraman Guhan , Cramer Steven M. 
Published: February 2006

AbstractAlthough the ability to carry out simultaneous concentration and purification in a single displacement step has significant advantages for downstream processing of pharmaceuticals, a major impediment to the implementation of displacement chromatography has been the lack of suitable displacer compounds. An important recent advance in the state of the art of displacement chromatography has been the discovery that low‐molecular‐weight dendritic polymers can be successfully employed as displacers for protein purification in ion‐exchange systems. In this article, protected amino acid esters (based on arginine and lysine) are shown to be useful displacers for protein purification in cation‐exchange systems. A dynamic affinity plot is employed to evaluate the affinity of these low‐molecular‐weight compounds under dis‐placement conditions. In contrast to large polyelectroyte displacers, the efficacy of these low‐molecular‐weight displacers was shown to be dependent on both the initial carrier salt concentration and the displacer concentration. In addition to the funcamental interest generated by low‐molecular‐weight displacers, it is likely that these displacers will have significant operatioal advantages as compared with large polyelectrolyte displacers. © 1995 John Wiley & Sons, Inc.
Approaches for increasing the solution stability of proteins
Authors: Manning Mark C. , Matsuura James E. , Kendrick Brent S. , Meyer Jeffrey D. , Dormish Jonathon J. , Vrkljan Michael , Ruth James R. , Carpenter John F. , Sheftert Eli 
Published: February 2006

AbstractStabilization of proteins through proper formulation is an important challenge for the pharmaceutical industry. Two approaches for stabilization of proteins in solution are discussed. First, work describing the effect of additives on the thermally induced denaturation and aggregation of low molecular weight urokinase is presented. The effects of these additives can be explained by preferential exclusion of the solute from the protein, leading to increased thermal stability with respect to denaturation. Diminished denaturation leads to reduced levels of aggregation. The second approach involves stoichiometric replacement of polar counter ions (e.g., chloride, acetate, etc.) with anionic detergents, in a process termed hydrophobic ion pairing (HIP). The HIP complexes of proteins have increased solubility in organic solvents. In these organic solvents, where the water content is limited, the thermal denautration temperatures greatly exceed those observed in aqueous solution. In addition, it is possible to use HIP to selectively precipitate basic proteins from formulations that contain large amounts of stabilizers, such as human serum albumin (HSA), with a selectivity greater than 2000‐fold. This has been demonstrated for various mixtures of HSA and interleukin‐4. © 1995 John Wiley & Sons, Inc.
Computer‐aided process analysis and economic evaluation for biosynthetic human insulin production—A case study
Authors: Petrides Demetri , Sapidou Elpida , Calandranis John 
Published: February 2006

AbstractHuman insulin was the first mammalian protein produced in bacteria using recombinant DNA technology. Two technologies were developed; the first based on the separate expression of precursors of chains A and B of insulin, and the second based on the expression of a precursor of proinsulin as a Trp‐E fusion protein. Both technologies utilized Escherichia coli as an expression system. Later, a third technology was developed based on a strain of yeast that can secrete a precursor of insulin. The second E. coli process, a variation of which has been commercialized by Eli Lilly and Co., is analyzed in this article from a process design and economic evaluation viewpoint. The objective of this work is to elucidate the technical complexity and high cost associated with the manufacturing of biopharmaceuticals. Human insulin is a good example of a protein‐based biopharmaceutical produced in large quantities (a fex tons per year) that requires large scale equipment and presents a multitude of scale‐up challenges. Based onthe analysis, a number of conclusions are drawn regarding the cost breakdown and cost dependency on process parameters. Recommendations are made for cost reduction and environmental impact minimization. This analysis was performed using a software tool for computer‐aided bioprocess design. © 1995 John Wiley & Sons, Inc.
Unprecedented ROMP Activity of Low‐Valent Rhenium–Nitrosyl Complexes: Mechanistic Evaluation of an Electrophilic Olefin Metathesis System
Authors: Frech Christian M. , Blacque Olivier , Schmalle Helmut W. , Berke Heinz , Adlhart Christian , Chen Peter 
Published: February 2006

AbstractThe reaction of [Re(H)(NO)2(PR3)2] complexes (1 a: R = PCy3; 1 b: R = PiPr3) with [H(OEt2)2][BArF4] ([BArF4] = tetrakis{3,5‐bis(trifluoromethyl)phenyl}borate) in benzene at room temperature gave the corresponding cations [Re(NO)2(PR3)2][BArF4] (2 a and 2 b). The addition of phenyldiazomethane to benzene solutions of 2 a and 2 b afforded the moderately stable cationic rhenium(I)‐benzylidene‐dinitrosyl‐bis(trialkyl)phosphine complexes 3 a and 3 b as [BArF4]− salts in good yields. The complexes 2 a and 2 b catalyze the ring‐opening metathesis polymerization (ROMP) of highly strained nonfunctionalized cyclic olefins to give polymers with relatively high polydispersity indices, high molecular weights and over 80 % Z configuration of the double bonds in the chain backbone. However, these complexes do not show metathesis activity with acyclic olefins. The benzylidene derivatives 3 a and 3 b are almost inactive in ROMP catalysis with norbornene and in olefin metathesis. NMR experiments gave the first hints of the initial formation of carbene complexes from [Re(NO)2(PR3)2][BArF4] (2 a and 2 b) and norbornene. In a detailed mechanistic study ESI‐MS/MS measurements provided further evidence that the carbene formation is initiated by a unique reaction sequence where the cleavage of the strained olefinic bond starts with phosphine migration forming a cyclic ylide–carbene complex, capable of undergoing metathesis with alternating rhenacyclobutane formation and cycloreversion reactions (“ylide” route). However, even at an early stage the ROMP propagation route is expected to merge into an “iminate” route by attack by the ylide function on one of the NNO atoms followed by phosphine oxide elimination. The formation of phosphine oxide was confirmed by NMR spectroscopy. The proposed mechanism is supported further by detailed DFT calculations.
Infrared‐Spectroscopic and Density‐Functional‐Theory Investigations of the LaCO, La2[η2(μ2‐C,O)], and c‐La2(μ‐C)(μ‐O) Molecules in Solid Argon
Authors: Xu Qiang , Jiang Ling , Zou Ru‐Qiang 
Published: February 2006

AbstractReactions of laser‐ablated lanthanum atoms with CO molecules in solid argon have been studied. The neutral lanthanum monocarbonyl (LaCO), produced upon sample deposition at 7 K, exhibits a CO stretching frequency of 1772.7 cm−1; to the best of our knowledge this is the lowest yet observed for a terminal CO in a neutral metal–carbonyl molecule (MCO, M=metal atom), implying anomalously enhanced metal‐to‐CO back‐bonding. The infrared (IR) absorption band at 1145.9 cm−1 is assigned to the CO stretching mode of the side‐on‐bonding CO in the La2[η2(μ2‐C,O)] molecule. This CO‐activated molecule undergoes an UV/Vis‐photoinduced rearrangement to the CO‐dissociated molecule, c‐La2(μ‐C)(μ‐O). Density functional theory (DFT) calculations have been performed on these molecules, the results of which lend strong support to the experimental assignments of the IR spectra. LaCO is predicted to have a quartet ground state, corresponding to a linear geometry. Its formation involves La 6s→4f promotion, which increases the strength of LaCO bonding by decreasing the σ repulsion and, remarkably, by increasing the La 5d and 4f→CO 2π back‐bonding. The observations schematically depict the whole process, starting with the interaction of CO with metal and ending with CO dissociation by the lanthanum dimer.
Platinum‐ and Gold‐Catalyzed Rearrangement Reactions of Propargyl Acetates: Total Syntheses of (−)‐α‐Cubebene, (−)‐Cubebol, Sesquicarene and Related Terpenes
Authors: Fürstner Alois , Hannen Peter 
Published: February 2006

AbstractPropargyl acetates, in the presence of catalytic amounts of late transition‐metal salts such as PtCl2 or AuCl3, represent synthetic equivalents of α‐diazoketones. This notion is corroborated by a concise approach to various sesquiterpene natural products starting from readily available substrates. Specifically, (+)‐carvomenthone (17) is converted into propargyl acetate (S)‐26 by a sequence involving Stille cross‐coupling of its kinetic enol triflate 18, regioselective hydroboration/oxidation of the resulting 1,3‐diene 19, and addition of an alkynyl cerium reagent to aldehyde 21 thus obtained. Since the latter step was found to be unselective, the configuration of the reacting propargyl acetate was unambiguously set by oxidation followed by diastereoselective transfer hydrogenation by using Noyori's catalyst 25. Compound (S)‐26, on treatment with PtCl2 in toluene, converted exclusively to the tricyclic enol acetate 27, which was saponified to give norcubebone 11 in excellent overall yield. The conversion of this compound into the sesquiterpene alcohol (−)‐cubebol (6) was best achieved with MeCeCl2 as the nucleophile, whereas the formation of the parent hydrocarbon (−)‐α‐cubebene (4) was effected in excellent yield by recourse to iron‐catalyzed cross coupling methodology developed in this laboratory. Since norketone 11 has previously been transformed into (−)‐β‐cubebene (5) as well as (−)‐4‐epicubebol 8, our approach constitutes formal total syntheses of these additional natural products as well. Along similar lines, the readily available propargyl acetates 1, 33 and 47 were shown to give access to 2‐carene 44, sesquicarene 39, and episesquicarene 51 in excellent overall yields. In this series, however, the cycloisomerization reaction was best achieved with catalytic amounts of AuCl3 in 1,2‐dichloroethane as the solvent. In addition to these preparative results, our data provide some insight into the mechanism of these remarkable skeletal rearrangement reactions. Transformations of this type are likely triggered by initial coordination of the alkyne unit of the substrate to the carbophilic transition‐metal cation. Formal attack of the alkene moiety onto the resulting π‐complex engenders the formation of an electrophilic cyclopropyl carbene species which subsequently reacts with the adjacent acetate unit to give the final product. The alternative phasing of events, implying initial attack of the acetate (rather than the alkene moiety) onto the metal–alkyne complex, is inconsistent with the stereochemical data obtained during this total synthesis campaign.
Three Alkali‐Metal Erbium Thiophosphates: From the Layered Structure of KEr[P2S7] to the Three‐Dimensional Cross‐Linkage in NaEr[P2S6] and Cs3Er5[PS4]6.
Authors: Komm Theresa , Schleid Thomas 
Published: February 2006

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.
K2M (H2P2O7)2×2H2O (M: Ni, Cu, Zn): Orthorhombic Forms and Raman Spectra.
Authors: Essehli Rachid , El Bali Brahim , Tahiri Aziz Alaoui , Lachkar Mohammed , Manoun Bouchaib , Dusek Michal , Fejfarova Karla 
Published: February 2006

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.
A Molecular Dynamics Study of the Thermodynamic Properties of Calcium Apatites. Part 1. Hexagonal Phases.
Authors: Cruz Fernando J. A. L. , Canongia Lopes Jose N. , Calado Jorge C. G. , Minas da Piedade Manuel E. 
Published: February 2006

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.
New Metal Iodates: Syntheses, Structures, and Characterizations of Noncentrosymmetric La(IO3)3 and NaYI4O12 and Centrosymmetric β‐Cs2I4O11 and Rb2I6O15 (OH)2×H2O.
Authors: Ok Kang Min , Halasyamani P. Shiv 
Published: February 2006

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.
High‐Pressure Synthesis of Novel Hydride in Mg—M Systems (M: Li, Pd).
Authors: Goto Y. , Kakuta H. , Kamegawa A. , Takamura H. , Okada M. 
Published: February 2006

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.
Enantiodiscrimination and Enantiocontrol of Neutral and Cationic PtII Complexes Bearing the Tropos Biphep Ligand: Application to Asymmetric Lewis Acid Catalysis.
Authors: Mikami Koichi , Kakuno Hitomi , Aikawa Kohsuke 
Published: February 2006

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.
Synthesis of New Chiral [2‐(1‐Hydroxyalkyl)pyrrolidino]methylferrocenes and Application to the Catalytic Asymmetric Addition of Diethylzinc to Arylaldehydes.
Authors: Xu Cui‐Lian , Wang Min‐Can , Hou Xue‐Hui , Liu Hong‐Min , Wang De‐Kun 
Published: February 2006

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.
Synthesis of P‐Chirogenic Diarylphosphinoacetic Acids and Their Proline Derivatives for Palladium‐Catalyzed Allylic Alkylation Reactions.
Authors: Lam Hubert , Horton Peter N. , Hursthouse Michael B. , Aldous David J. , Hii King Kuok 
Published: February 2006

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.