bluuebunny/crossref_metadata_2025 huggingface dataset:
Intracellular calcium activity in isolated bovine adrenal chromaffin cells in the presence and absence of 60 Hz magnetic fields
Authors: Craviso Gale L. , Poss James , Lanctot Christine , Lundback Steven S. , Chatterjee Indira , Publicover Nelson G.
Published: October 2002

This study examined whether 60 Hz magnetic field (MF) exposure alters intracellular calcium levels ([Ca2+]i) in isolated bovine adrenal chromaffin cells, a classic model of neural responses. [Ca2+]i was monitored by fluorescence video imaging of cells loaded with the calcium indicator fluo‐4 during exposures to magnetic flux densities of 0.01, 0.1, 1.0, 1.4, or 2.0 mT. MFs generated by Helmholtz coils constructed from bifilar wire allowed both 60 Hz field and sham exposures. Following a 5 min monitoring period to establish baseline patterns, cells were subjected for 10 min to a 60 Hz MF, sham field or no field. Reference calcium responses and assessment of cell excitability were obtained by the sequential addition of the nicotinic cholinergic receptor agonist dimethylphenylpiperazinium (DMPP) and a depolarizing concentration of KCl. Throughout an 8 day culture period, cells exhibited spontaneous fluctuations in [Ca2+]i. Comparisons of the number of cells exhibiting transients, the number and types of calcium transients, as well as the time during monitoring when transients occurred showed no significant differences between MF exposed cells and either sham exposed or nonexposed cells. With respect to the percentage of cells responding to DMPP, differences between 1 and 2 mT exposed cells and both nonexposed and sham exposed cells reached statistical significance during the first day in culture. No statistically significant differences were observed for responses to KCl. In summary, our data indicate that [Ca2+]i in chromaffin cells is unaffected by the specific 60 Hz MF intensities used in this study. On the other hand, plasma membrane nicotinic receptors may be affected in a manner that is important for ligand–receptor interactions. Bioelectromagnetics 23:557–567, 2002. © 2002 Wiley‐Liss, Inc.
Occupational exposures to high frequency electromagnetic fields in the intermediate range ( >300 Hz–10 MHz)
Authors: Floderus Birgitta , Stenlund Carin , Carlgren Frank
Published: October 2002

The aim of this study was to identify work situations with electromagnetic fields of 300 Hz–10 MHz and to characterize the occupational exposure. Work place investigations included descriptions of the work environment and physical measurements. We estimated electric (E) and magnetic (H) fields by spot measurements in air, by logged exposure data, and when possible, we recorded induced currents in limbs. The instruments used were Wandel and Golterman EFA‐3, NARDA 8718, Holaday HI‐3702. The exposure sources comprised five induction furnaces, seven induction heaters, one surface treatment equipment, four units of electronic article surveillance (EAS), and medical devices for surgery and muscle stimulation. The induction furnaces operated at 480 Hz–7 kHz, and the maximum values of logged data varied between 512–2093 V/m (E field) and 10.5–87.3 A/m (H field). The induction heaters (3.8 kHz–1.25 MHz) also showed high maximum exposure values of both E and H fields. Three EAS units, an electromagnetic plate at a library, a luggage control unit, and an antitheft gate, showed E fields reaching 658–1069 V/m. The H fields were comparatively lower, except for the antitheft gate (5 and 7.5 kHz) showing a maximum value of 27.2 A/m (recorded during repair). Induced currents of 5–13 mA were measured for the medical devices. The study improves the basis for an exposure assessment for epidemiological studies of long term effects of exposures to high frequency electromagnetic fields. Bioelectromagnetics 23:568–577, 2002. © 2002 Wiley‐Liss, Inc.
Influence of 1 and 25 Hz, 1.5 mT magnetic fields on antitumor drug potency in a human adenocarcinoma cell line
Authors: Ruiz‐Gómez M.J. , de la Peña L. , Prieto‐Barcia M.I. , Pastor J.M. , Gil L. , Martínez‐Morillo M.
Published: October 2002

The resistance of tumor cells to antineoplastic agents is a major obstacle during cancer chemotherapy. Many authors have observed that some exposure protocols to pulsed electromagnetic fields (PEMF) can alter the efficacy of anticancer drugs; nevertheless, the observations are not clear. We have evaluated whether a group of PEMF pulses (1.5 mT peak, repeated at 1 and 25 Hz) produces alterations of drug potency on a multidrug resistant human colon adenocarcinoma (HCA) cell line, HCA‐2/1cch. The experiments were performed including (a) exposures to drug and PEMF exposure for 1 h at the same time, (b) drug exposure for 1 h, and then exposure to PEMF for the next 2 days (2 h/day). Drugs used were vincristine (VCR), mitomycin C (MMC), and cisplatin. Cell viability was measured by the neutral red stain cytotoxicity test. The results obtained were: (a) The 1 Hz PEMF increased VCR cytotoxicity (P < 0.01), exhibiting 6.1% of survival at 47.5 μg/ml, the highest dose for which sham exposed groups showed a 19.8% of survival. For MMC at 47.5 μg/ml, the % of survival changed significantly from 19.2% in sham exposed groups to 5.3% using 25 Hz (P < 0.001). Cisplatin showed a significant reduction in the % of survival (44.2–39.1%,P < 0.05) at 25 Hz and 47.5 μg/ml, and (b) Minor significant alterations were observed after nonsimultaneous exposure of cells to PEMF and drug. The data indicate that PEMF can induce modulation of cytostatic agents in HCA‐2/1cch, with an increased effect when PEMF was applied at the same time as the drug. The type of drug, dose, frequency, and duration of PEMF exposure could influence this modulation. Bioelectromagnetics 23:578–585, 2002. © 2002 Wiley‐Liss, Inc.
Cylindrical waveguide applicator for in vitro exposure of cell culture samples to 1.9‐GHz radiofrequency fields
Authors: Gajda G.B. , McNamee J.P. , Thansandote A. , Boonpanyarak S. , Lemay E. , Bellier P.V.
Published: October 2002

An applicator for in vitro cell culture exposure was developed based on a circularly polarized, cylindrical waveguide for the 1.9‐GHz frequency band used by Personal Communications Services (PCS) in Canada. The applicator consists of two coaxial Petri dishes that sit on the open end of the cylindrical waveguide. The inner 60‐mm Petri dish contains the cell culture while the outer 150‐mm dish contains coolant water, which is circulated from a pump. A dosimetric evaluation was made using thermometric and E‐field probe techniques. The latter allowed the entire inner dish to be scanned to determine the range of specific absorption rates (SARs) pertinent to the expected position of the cells. A representative SAR rate (SAR per unit of input power) of 8.6 ± 2.1 W/kg/W (95th percentile) was determined 1 mm from the bottom, for a 10 ml sample volume of standard medium. Evaluation of the cooling system demonstrated that following an initial 0.3 °C temperature increase, a constant temperature was maintained for 24 h when the waveguide was energized to achieve an average sample SAR of 10 W/kg. These properties enable both acute and sub‐acute in vitro bio‐effect studies to be performed on a variety of cell culture samples. Bioelectromagnetics 23:592–598, 2002. © 2002 Wiley‐Liss, Inc.
Immunomodulating action of low intensity millimeter waves on primed neutrophils
Authors: Safronova Valentina G. , Gabdoulkhakova A.G. , Santalov B.F.
Published: October 2002

Comparative investigation of the susceptibility of intact and primed neutrophils of the NMRI strain mice to low intensity millimeter wave (mm wave) irradiation (41.95 GHz) was performed. The specific absorption rate was 0.45 W/kg. Isolated neutrophils were primed by a chemotactic peptide N‐formyl‐methionyl‐leucyl‐phenylalanine (fMLP) at a subthreshold concentration of 10 nM for 20 min, and then the cells were activated by 1 μM fMLP. Production of the reactive oxygen species (ROS) was estimated by the luminol dependent chemiluminescence technique. It was found that the preliminary mm wave irradiation of the resting cells at 20 °C did not act on the ROS production induced by the chemotactic peptide. The exposure of the primed cells results in a subsequent increase in the fMLP response. Therefore, the primed neutrophils are susceptible to the mm waves. Specific inhibitors of the protein kinases abolished the mm wave effect on the primed cells. The data indicate that protein kinases actively participate in transduction of the mm wave signal to effector molecules involved in neutrophil respiratory burst. Bioelectromagnetics 23:599–606, 2002. © 2002 Wiley‐Liss, Inc.
Exposure to power frequency magnetic fields and X‐Rays induces GAP‐43 gene expression in human glioma MO54 cells
Authors: Ding Gui‐Rong , Nakahara Takehisa , Miyakoshi Junji
Published: October 2002

We investigated the distribution and expression of growth associated protein‐43 (GAP‐43) in human glioma cells (MO54) after exposure to a magnetic field (60 Hz, 5 mT), with or without initial X‐ionizing radiation (2 Gy), by using immunocytochemistry and the reverse transcription polymerase chain reaction (RT‐PCR). GAP‐43 was present in the cytoplasm, accumulating in the perinuclear area. An increase in GAP‐43 expression was observed with a peak at 10 h at the mRNA level and at 12 h at the protein level, after exposure to the magnetic field. The increased level of GAP‐43 protein returned to a normal level within 24 h of exposure to a 5 mT magnetic field. The kinetic pattern of GAP‐43 expression induced by X‐ionizing radiation was very similar to that induced by the magnetic field. These results suggest that the stimulation of GAP‐43 expression could occur by a similar mechanism following exposure to X‐rays or magnetic fields. We have provided the first evidence that exposure to a 5 mT magnetic field can induce GAP‐43 gene expression in human glioma MO54 cells. Bioelectromagnetics 23:586–591, 2002. © 2002 Wiley‐Liss, Inc.
Effect of millimeter waves on cyclophosphamide induced suppression of the immune system
Authors: Logani Mahendra K. , Anga Altaf , Szabo Imre , Agelan Alexis , Irizarry Armando R. , Ziskin Marvin C.
Published: October 2002

The effect of millimeter electromagnetic waves (MWs) on cyclophosphamide (CPA) induced toxicity to leukocytes, bone marrow cells, and T‐cell‐mediated immunity was examined. For studying the effect of MWs on CPA induced leukopenia and myelosuppression, BALB/C mice were irradiated for 3 days, 30 min each day, prior to administration of CPA (200 mg/kg). MWs were produced with a Russian made YAV‐1 generator. The device produced 42.2 ± 0.2 GHz modulated wave radiation through a 10 mm × 20 mm rectangular output horn. The animals were irradiated on the nose area. Peak SAR and incident power density were measured as 622 ± 100 W/kg and 31 ± 5 mW/cm2, respectively. For studying the effect of MWs on CPA induced suppression of T‐cell mediated immunity, a delayed type hypersensitivity (DTH) assay in mouse skin was used. The DTH reaction in mouse skin was induced by topical application of dinitrochlorobenzene (DNCB) and quantified by measuring the increase in ear thickness and by histological examination. Treatment of animals with CPA significantly (P < 0.05) reduced leukocyte and bone marrow cell population, but MW irradiation did not show any significant protection from the immunosuppressive effects of CPA. Furthermore, MW irradiation did not protect the animals from CPA induced suppression of T‐cell mediated immunity. Bioelectromagnetics 23:614–621, 2002. © 2002 Wiley‐Liss, Inc.
Orientation of Paramecium swimming in a DC magnetic field
Authors: Nakaoka Yasuo , Takeda Ryutaro , Shimizu Kikuo
Published: October 2002

We found that a ciliated protozoan, Paramecium, swam perpendicular to a static (DC) magnetic field (0.68 T). The swimming orientation was similar even when the ionic current through the cell membrane disappeared after saponin treatment. To determine the diamagnetic anisotropy of intracellular organs, macronuclei, cilia, and secretory vesicles, trichocysts, were selectively isolated. Both cilia and trichocysts tended to align their long axis parallel to the magnetic field (0.78 T). Paramecium mutants that lack trichocysts also swam perpendicular to the magnetic field, although the proportion fraction was smaller than the normal population. Since large numbers of cilia and trichocysts are arranged at right angles to the long axis of the cell, the diamagnetic anisotropies of cilia and trichocysts cause the long axis of the cell to align perpendicular to the magnetic field. In contrast to the DC magnetic field, an alternative (AC) magnetic field (60 Hz, 0.65 T) had almost no effect on the swimming orientation of Paramecium. Bioelectromagnetics 23:607–613, 2002. © 2002 Wiley‐Liss, Inc.
Thermal noise limit on the sensitivity of cellular membranes to power frequency electric and magnetic fields
Authors: Kaune W.T.
Published: October 2002

Several authors have concluded that thermal electromagnetic noise will be of sufficient magnitude to overwhelm electric and/or magnetic fields induced by environmentally generated, power frequency electric and magnetic fields in the membranes of living cells located in the bodies of humans. Yet, there are research reports that indicate that living cells may respond to power frequency electric and/or magnetic field levels well below the limits set by these thermal noise arguments. The purpose of this study is to suggest that published thermal arguments may not make a full accounting of all membrane force fields of thermal origin, and that when such an accounting is made, the net thermal noise fields may be smaller in the power frequency range than previously thought. If this analysis is correct, there may be no thermal noise barrier that precludes the possibility of cellular membranes of human cells responding to environmental levels of power frequency electric or magnetic fields. Bioelectromagnetics 23:622–628, 2002. © 2002 Wiley‐Liss, Inc.
Ab initio calculations for the optical rotations of conformationally flexible molecules: A case study on six‐, seven‐, and eight‐membered fluorinated cycloalkanol esters
Authors: Grimme Stefan , Bahlmann Arnold , Haufe Günter
Published: October 2002

Based on the time‐dependent density functional response theory, an approach for the prediction of optical rotations of enantiomers of conformationally flexible molecules was developed. The method was applied successfully for the determination of the absolute configuration oftrans‐2‐fluorocycloalkanol acetates with different ring rizes. The largest deviations between experimental and theoretical [α]Dvalues are10 deg. · [dm · (g/cc)]−1(about 20% error). These theoretical results suggest that the optical rotation in these molecules is dominated by the local (1R;2R) configuration of the two substituents and that different ring and even axial/equatorial orientations play a less important role. Chirality 14:793–797, 2002. © 2002 Wiley‐Liss, Inc.
Liquid chromatographic retention behavior and enantiomeric separation of three chiral center β‐blocker drug (nadolol) using heptakis (6‐azido‐6‐deoxy‐2, 3‐di‐O‐phenylcarbamolyted) β‐cyclodextrin bonded chiral stationary phase
Authors: Wang Xin , Ching Chi Bun
Published: October 2002

Nadolol, a β‐blocker used in the management of hypertension and angina pectoris, has three chiral centers and is currently marketed as an equal mixture of its four stereoisomers. Enantiomeric separation of nadolol by high‐performance liquid chromatography was studied on a column packed with novel heptakis (6‐azido‐6‐deoxy‐2, 3‐di‐O‐phenylcarbamolyted) β‐cyclodextrin bonded chiral stationary phase. The retention behavior and resolution of nadolol enantiomers were investigated and discussed with respect to the mobile phase composition and flow rate, pH, ionic strength, and temperature. The optimal separation condition was found; the mobile phase contained 80% buffer solution (1% triethylamine acetate, pH 5.5) and 20% methanol with 0.3 ml/min mobile phase flow rate at a temperature of 20°C. At the optimal conditions, resolution of three stereoisomers of nadolol was obtained with a complete separation of the most active enantiomer, (RSR)‐nadolol. Thermodynamic properties including enthalpy and entropy change of binding to the CSP for the enantiomeric separation were also determined. Chirality 14:798–805, 2002. © 2002 Wiley‐Liss, Inc.
Recent development of asymmetric syntheses based on the Meerwein‐Ponndorf‐Verley reduction
Authors: Nishide Kiyoharu , Node Manabu
Published: October 2002

Stereoselective Meerwein‐Ponndorf‐Verley (MVP) reductions, including intermolecular MPV reductions, intramolecular MPV reductions (asymmetric 1,5‐ and 1,7‐hydride shifts), catalytic MPV reduction, and reactions related to the MPV reduction are reviewed from the standpoint of asymmetric synthesis. Chirality 14:759–767, 2002. © 2002 Wiley‐Liss, Inc.
Release of salbutamol sulphate and ketoprofen enantiomers from matrices containing HPMC and cellulose derivatives
Authors: Solinís M. Angeles , de la Cruz Yaimy , Calvo Begoña , Hernández Rosa M. , Gascón Alicia R. , Goñi Isabel , Gurruchaga M. Dolores , Pedraz José Luis
Published: October 2002

We studied the release of salbutamol and ketoprofen enantiomers from HPMC K100M matrices containing two types of cellulose derivatives: cellulose tris (3,5‐dimethylphenylcarbamate) and cellulose tris (2,3‐dichlorophenylcarbamate), chiral excipients used as stationary phases for liquid chromatography. These matrices provided an extended release of both drugs. Ketoprofen release from formulations elaborated with cellulose tris (2,3‐dichlorophenylcarbamate) was by anomalous transport, because the value of n (release exponent of the diffusion equation) ranged between 0.60–0.68, whereas for all other formulations the value of exponent n ranged from 0.50–0.54. The drug thus diffuses through the matrix and is released following a quasi‐Fickian diffusion mechanism (stereoselective process). The matrices preferentially retained R‐salbutamol and S‐ketoprofen and cellulose tris (3,5‐dimethylphenylcarbamate) showed more capacity of chiral discrimination for both drugs than cellulose tris (2,3‐dichlorophenylcarbamate). Moreover, we observed that stereoselectivity is dependent on the amount of chiral excipient in the formulation. Diffusion tests confirmed the chiral interaction between drugs and cellulose derivatives observed in the dissolution assays except for matrices elaborated with ketoprofen and cellulose tris (2,3‐dichlorophenylcarbamate), where the low stereoselectivity observed with the matrices is due to the presence of HPMC K100M. We conclude that the inclusion of these cellulose derivatives in HPMC matrices does not result in a relevant stereoselectivity with respect to the two drugs studied. Chirality 14:806–813, 2002. © 2002 Wiley‐Liss, Inc.
Solution structure of diastereomeric thymidine 3′‐O(N,N‐diisopropyl‐O‐β‐cyanoethyl‐phosphoramidothioate)s by NMR spectroscopy
Authors: Gács‐Baitz Eszter , Kajtár‐Peredy Mária
Published: October 2002

The conformational properties of a diastereomeric nucleoside‐phosphorothioate pair is reported as reflected by different NMR parameters. Configurational assessment is based partly on the different NOE (nuclear overhauser enhancement) effects of the individual isomers and on the trends observed in other NMR parameters. Vicinal carbon‐phosphorus couplings reflect the predominance of the ϵ‐ conformation for the Sp isomer and the ϵt conformation for the Rp isomer. The effects of solvent and temperature on these vicinal couplings are described and the results are interpreted in terms of conformational shift towards the preferred ϵt conformation. Chirality 14:814–818, 2002. © 2002 Wiley‐Liss, Inc.
Optical rotation: Recent advances in determining the absolute configuration
Authors: Polavarapu Prasad L.
Published: October 2002

The field of optical rotations is currently undergoing a renaissance, which is a direct result of the advances in quantum mechanics and the availability of faster desktop computers. In the last few years, the field of optical rotations has taken an important role for determining the three‐dimensional molecular structure (absolute configuration and conformations) with confidence. The purpose of this review is to present the latest advances in this area so that practicing chemists can utilize them in their respective areas of research and development. Chirality 14:768–781, 2002. © 2002 Wiley‐Liss, Inc.
Polyproline II structure in proteins: Identification by chiroptical spectroscopies, stability, and functions
Authors: Bochicchio Brigida , Tamburro Antonio Mario
Published: October 2002

In the last years polyproline II (PPII) structure has been demonstrated to be essential to biological activities such as signal transduction, transcription, cell motility, and immune response. The polyproline left‐handed helical structure was nearly unknown until now and often confused with unordered, disordered, irregular, unstructured, extended, or random coil conformations because it is neither α‐helical nor β‐turn nor β‐sheet, i.e., a classical structure. In spite of the regularity of the PPII structure and, more precisely, its well‐defined dihedral angle values, a typical feature of PPII structure is the absence of any intramolecular hydrogen bonds that renders the PPII structure indistinguishable from an irregular backbone structure by 1H‐NMR spectroscopy. The only way to unambiguously reveal PPII structure in solution is to use spectroscopies based on optical activity, such as circular dichroism (CD), vibrational circular dichroism (VCD), and Raman optical activity (ROA). Herein we focus on the identification of PPII structure by CD, widely considered to be the most reliable methodology. Then we report on VCD and ROA spectroscopies as tools in the identification of PPII structure. A third section is dedicated to the analysis of the stabilization of PPII conformation in aqueous solution. Finally, the significance of PPII in self‐assembly processes, in elasticity of elastomeric proteins, and in proteins‐(peptides) proteins molecular recognition processes are considered. Chirality 14:782–792, 2002. © 2002 Wiley‐Liss, Inc.
Polar signal averaging
Authors: Thomas G.W. , Bachman H.N. , Sigmund E.E. , Mitrović V.F. , Calder E.S. , Halperin W.P.
Published: October 2002

Signals suffering from phase noise, such as spin echoes from NMR experiments in a fluctuating magnetic field, can be underestimated by traditional signal averaging. Averaging in the polar rather than in the Cartesian domain can solve this problem. However, because of background noise, there is an inherent drawback in the polar averaging technique: polar averaging under conditions of a low initial signal to noise will cause these same signals to be overestimated. We studied this problem with both numerical simulations and experiments. The quantitative results allow not only an assessment of the applicability of polar averaging for a given experiment but also possible corrections of the overestimate. © 2002 Wiley Periodicals, Inc. Concepts Magn Reson 14: 359–364, 2002
Data acquisition and analysis of broad chemical‐shift powder patterns from solids with spin–echo techniques
Authors: Van Bramer S.E. , Glatfelter A. , Bai S. , Dybowski C. , Neue G.
Published: October 2002

The data acquisition and processing of the wide‐line chemical‐shift NMR spectra of solids present unique challenges. Developing procedures to minimize and address inherent distortions is critical for the proper determination of NMR chemical‐shift parameters from these wide‐line spectra. The analysis of such data provides an understanding of many assumptions that are made about solids and liquids in spectroscopy. We discuss techniques for the analysis of spin–echo spectra broadened by chemical‐shift dispersion. © 2002 Wiley Periodicals, Inc. Concepts Magn Reson 14: 365–387, 2002
Signal de‐noising in magnetic resonance spectroscopy using wavelet transforms
Authors: Cancino‐De‐Greiff Hector F. , Ramos‐Garcia Rubersy , Lorenzo‐Ginori Juan V.
Published: October 2002

Computer signal processing is used for quantitative data analysis (QDA) in magnetic resonance spectroscopy (MRS). The main difficulty in QDA is that MRS signals appear to be contaminated with random noise. Noise reduction can be achieved by coherent averaging, but it is not always possible to average many MRS waveforms. Wavelet shrinkage de‐noising (WSD) is a technique that can be employed in this case. The potentialities of WSD in MRS, alone and combined with the Cadzow algorithm, are analyzed through computer simulations. The results can facilitate an appropriate application of WSD, as well as a deeper understanding of this technique. © 2002 Wiley Periodicals, Inc. Concepts Magn Reson 14: 388–401, 2002
Maximum likelihood constrained deconvolution. I: Algorithm and qualitative and quantitative enhancement in synthetic two‐dimensional NMR spectra
Authors: Jeong Gwang‐Woo , Kang Heoung‐Keun
Published: October 2002

The maximum likelihood method is a constrained iterative spectral deconvolution technique in which a spectral fitting model is determined by minimizing the variance of fit in the time domain in a nonlinear iterative manner. Application of this method to synthetic 2‐dimensional (2‐D) NMR spectra, which have heavily overlapped multiplets associated with low signal to noise ratios, yields contrast‐enhanced spectra with simultaneous noise suppression and resolution improvement. This protocol greatly facilitates peak recognition and often partitions overlapping multiplets into individual components, leading to a more accurate interpretation of resonance frequencies, coupling constants, and multiplets than does the conventional apodization or Fourier transform method. These advantages are useful for constructing reliable 3‐D molecular structures for complex molecular systems. © 2002 Wiley Periodicals, Inc. Concepts Magn Reson 14: 402–415, 2002
Color difference predicted by color component differences
Authors: Indow Tarow
Published: October 2002

A relationship between assessed color differences and assessed components of colors is presented. The perceptual difference between colors j and k is converted to a lightness difference of two Munsell grays, VA and VB, and djk = |VA − VB|. Scaled values of principal hue components of a color ξα(H|V/C), α = R, Y, G, and B, are read from charts based on assessments of observers. Previous charts (Color Research and Application, 1999, 24, 266–279) are enlarged and extended. A linear combination of ΔV = |Vj − Vk| and Δξα = |ξα(Hj|Vj/Cj) − ξα(Hk|Vk /Ck)|, d̃jk, is the best to predict djk. The root‐mean‐squares of (djk − d̃jk) is 0.34 V, about one third of the lightness difference from V to V + 1 on the Munsell Value Scale.
Influence of chemical and mineralogical composition on color for commercial talcs
Authors: Soriano M. , Sánchez‐Marañón M. , Melgosa M. , Gámiz E. , Delgado R.
Published: October 2002

Commercial talcs are pulverized mineral products with a variable chemical and mineralogic composition, widely used in industry. Although generally white, they have color variations. The aim of this study was to establish relationships between color parameters and the chemical and mineralogic composition of commercial talc samples, in order to investigate the causes of color. Chlorite, dolomite, magnesite, and calcite were the most abundant accessory minerals. Fe, Mn, Ti, and Ni were the most abundant chromophore chemical elements. Factor statistical analysis (89.8% of total variance explained) revealed that the influence of each mineral species on the different color parameters a*, b*, and L* is well defined (the highest loading factors). Chlorite associated with Fe, Mn, Ti, Zr, Cu, Zn, and V, and calcite associated with Zn, Cu, Sr (and, to a lesser degree, Fe, Mn, Ni, and Co) affect the color parameters a* and b* by inducing chromatic variations (greening and yellowing). Dolomite and magnesite associated with Fe, Sr, Ni, Co, V (and, to a lesser extent, Mn and Cu) affect L* by inducing darkening.
Environmental colour design for the third millennium: An evolutionary standpoint
Authors: Tosca Theano Fannie
Published: October 2002

This is a study based on observation, research, literature, and design of the effect of environmentally applied colour on human evolution. Given the structuring abilities of colour, here, it is first examined here how it can help to make the emerging man–environment system a living evolvable entity. Then follows a description of a related design approach for improvement by lighting design as practiced recently by world‐known artists and researched by the Colour Semiotics Study Group under the author's direction. It is argued that, by its increasing complexity, flexibility, and sensorimotor stimulation, environmental colour may raise not only the visual but also the broader perceptual capacities of man with regard to selected qualities. The extension of the human consciousness through machine‐aided imagery and scientific knowledge, finally, calls for a new kind of colour–light organization of the environment, based on the interplay of sensory stimulation and intellectual processes, professional design, and user interaction, in tune with our new understanding of the cosmologic law as constant regeneration. The very structure of this article is intended to exemplify the concept of the portended intertwining of cognitive and intuitive processes in the act of creation central to the study.
Transition metals and polyol pathway in the development of diabetic neuropathy in rats
Authors: Nakamura Jiro , Hamada Yoji , Chaya Sadao , Nakashima Eitaro , Naruse Keiko , Kato Koichi , Yasuda Yutaka , Kamiya Hideki , Sakakibara Fumihiko , Koh Naoki , Hotta Nigishi
Published: October 2002

Background

The transition metal–catalyzed reaction is a major source of oxygen free radicals, which play an important role in vascular dysfunction leading to ischemia in diabetic tissues. The inhibition of polyol pathway hyperactivity has been reported to ameliorate neurovascular abnormalities in diabetic rats and has been proposed to improve the oxygen free radical scavenging capacity. The present study was conducted to compare the effect of a transition metal chelating agent, trientine (TRI), on diabetic neuropathy with that of an aldose reductase inhibitor, NZ‐314 (NZ).

Methods

Diabetic rats were divided into three groups: (1) untreated, (2) TRI‐treated, and (3) NZ‐treated. TRI (20 mg/kg) or NZ (100 mg/kg) was administered by gavage or chow containing NZ, respectively, for 8 weeks. Motor nerve conduction velocity (MNCV), coefficient of variation of the R − R interval on electrocardiogram (CVr‐r), sciatic nerve blood flow (SNBF), platelet aggregation activities, and serum concentrations of malondialdehyde were measured.

Results

Untreated diabetic rats showed delayed MNCV, decreased CVR−R, and reduced SNBF compared to normal rats. TRI or NZ completely prevented these deficits. Platelet hyperaggregation activities in diabetic rats were prevented by NZ, but not by TRI. Increased concentrations of malondialdehyde in diabetic rats were partially but significantly ameliorated by either TRI or NZ.

Conclusions

These observations suggest that increased free radical formation through the transition metal–catalyzed reaction plays an important role in the development of diabetic neuropathy and that the preventive effect of an aldose reductase inhibitor on diabetic neuropathy may also be mediated by decreasing oxygen free radicals. Copyright © 2002 John Wiley & Sons, Ltd.
An adipocentric view of signaling and intracellular trafficking
Authors: Mora Silvia , Pessin Jeffrey E.
Published: October 2002

Adipocytes have traditionally been considered to be the primary site for whole body energy storage mainly in the form of triglycerides and fatty acids. This occurs through the ability of insulin to markedly stimulate both glucose uptake and lipogenesis. Conventional wisdom held that defects in fuel partitioning into adipocytes either because of increased adipose tissue mass and/or increased lipolysis and circulating free fatty acids resulted in dyslipidemia, obesity, insulin resistance and perhaps diabetes. However, it has become increasingly apparent that loss of adipose tissue (lipodystrophies) in both animal models and humans also leads to metabolic disorders that result in severe states of insulin resistance and potential diabetes. These apparently opposite functions can be resolved by the establishment of adipocytes not only as a fuel storage depot but also as a critical endocrine organ that secretes a variety of signaling molecules into the circulation. Although the molecular function of these adipocyte‐derived signals are poorly understood, they play a central role in the maintenance of energy homeostasis by regulating insulin secretion, insulin action, glucose and lipid metabolism, energy balance, host defense and reproduction. The diversity of these secretory factors include enzymes (lipoprotein lipase (LPL) and adipsin), growth factors [vascular endothelial growth factor (VEGF)], cytokines (tumor necrosis factor‐α, interleukin 6) and several other hormones involved in fatty acid and glucose metabolism (leptin, Acrp30, resistin and acylation stimulation protein). Despite the large number of molecules secreted by adipocytes, our understanding of the pathways and mechanisms controlling intracellular trafficking and exocytosis in adipocytes is poorly understood. In this article, we will review the current knowledge of the trafficking and secretion processes that take place in adipocytes, focusing our attention on two of the best characterized adipokine molecules (leptin and adiponectin) and on one of the most intensively studied regulated membrane proteins, the GLUT4 glucose transporter. Copyright © 2002 John Wiley & Sons, Ltd.
Current knowledge of Japanese type 1 diabetic syndrome
Authors: Abiru Norio , Kawasaki Eiji , Eguch Katsumi
Published: October 2002

The Japanese have one of the lowest incidence of childhood type 1 diabetes in the world, but the incidence of this disease is clearly increasing within the Japanese population, as reported in several European countries. Latent autoimmune diabetes mellitus in adult (LADA) patients are also likely to have a lower incidence compared to Caucasians. Among the non‐autoimmune (type 1B) diabetes in Japanese adults, there exists a novel subtype of type 1 diabetes characterized by extremely rapid onset and pancreatic exocrine inflammation. HLA and non‐HLA gene associations to type 1 diabetes may vary depending on ethnic origin. Highly susceptible HLA haplotypes of type 1 diabetes observed in Caucasian patients are not found in Japanese patients, while protective HLA haplotypes are similar. Association studies of non‐HLA genes have identified several candidate genes that influence the heterogeneity of disease phenotypes as well as disease susceptibility to type 1 diabetes. The INS‐VNTR gene or polymorphisms of MICA gene are associated with susceptibility, whereas a certain allele of MICA gene and IL‐10 gene polymorphism are associated with clinical heterogeneity of the disease. An expression of multiple autoantibodies to a biochemically determined autoantigen confers a high risk for progression to type 1 diabetes. The combined evaluation of multiple autoantibodies is more sensitive than is ICA testing for the diagnosis of type 1 diabetes. A high titer of GAD autoantibody has the predictive value of future insulin deficiency in patients with LADA. For accurate predictive strategies of future insulin deficiency, combinational multiple autoantibodies analysis or genetic determination should be considered for effective immune intervention. Copyright © 2002 John Wiley & Sons, Ltd.
Children with dyslexia are slow to articulate a single speech gesture
Authors: Fawcett Angela J. , Nicolson Roderick I.
Published: October 2002

In addition to their well‐established problems in phonological processing, children with dyslexia show reduced speed of articulation. Two groups of children with dyslexia, mean ages 13 and 16 years, participated together with two groups of normally achieving children matched for age and IQ, with 33 participants in total. Participants were asked to articulate repeatedly, as fast as they could, either a single articulatory gesture /p/ /t/ or /k/ or the sequence ‘putuku’. The waveforms generated were analysed in two ways; the time per gesture excluding inter‐articulatory pauses (articulatory duration); and the mean time including the pauses (gesture duration). No age effects were found, but dyslexic groups were significantly slower on all tests. Deficits were greater in relative magnitude for gesture duration than articulatory duration. The results suggest that children with dyslexia have significant problems in articulation, not only in gesture planning, but also in the speeded production of single articulatory gestures. Copyright © 2002 John Wiley & Sons, Ltd.
Comments on ‘the dyslexia ecosystem’: a reply to Nicolson
Authors: Richards Ian L. , Witton Caroline , Moores Elisabeth , Reddy Peter A. , Rippon Gina , Talcott Joel B.
Published: October 2002

The central issue facing the dyslexia community, and the underlying theme of Nicolson's ‘The Dyslexia Ecosystem’ (Nicolson, 2002, Dyslexia, 8, 55–66), is how we can best translate what we know about this particular developmental disorder into practice to give each child the greatest opportunity of acquiring the enabling skill of literacy. To achieve this, and notwithstanding Nicolson's caveat on this point, we have to consider how we can best move from our sphere of expertise to a greater sphere of influence, both as individuals and as a community of research practitioners. In our response, we first consider aspects of Nicolson's general analysis of ‘The Dyslexia Ecosystem’ and then examine some of the specific objectives that have been proposed. Copyright © 2002 John Wiley & Sons, Ltd.
The association of abnormal cerebellar function in children with developmental coordination disorder and reading difficulties
Authors: O'Hare Anne , Khalid Shabana
Published: October 2002

Children with developmental coordination disorder/dyspraxia (DCD) are at high risk of reading and writing delay. The difficulties with motor skills are heterogeneous and many children have features of poor cerebellar function, reflected in problems with posture, balance and fast accurate control of movement. This study confirmed a high level of parental reporting of reading and writing delay in a clinical group of 23 children with DCD, defined on the basis of both clinical examination and standardized testing of motor function. Direct measurement of reading delay, identified still further children in the group. Those children with reading delay had associated findings typical of phonological awareness difficulties. The children also underwent a standardized test of neurological function and although they all had difficulties with cerebellar function, no distinctive pattern emerged for those whose presentation was complicated by delayed reading and writing. Both the children with DCD and 136 typically developing children, completed the pilot parental questionnaire on gross motor skills. The three skills of catching a ball, jumping on a moving playground roundabout and handwriting, distinguished the children with DCD. This study therefore confirms that children with DCD should be assessed for difficulties in phonological awareness. Additionally, children aged between 7 and 12 years are on the whole, highly competent in a range of gross motor skills and further study might determine whether a simple parental questionnaire might detect children who would benefit from further assessment. The study also suggests that all the children with DCD have cerebellar dysfunction and further work with a larger group might determine particular patterns associated with reading delay. Copyright © 2002 John Wiley & Sons, Ltd.
Electromagnetic analysis of inductrack magnetic levitation
Authors: Murai Toshiaki , Hasegawa Hitoshi
Published: October 2002

A new type of magnetic levitation system called the Inductrack has been proposed by R. F. Post. This system is composed of a special arrangement of permanent magnets on board which is called the Halbach array, and a close‐packed array of shorted coils in the longitudinal direction on the ground. This composition can obtain a large magnetic force, a very low take‐off speed, and a high lift‐to‐drag ratio. This paper describes numerical simulations of the Inductrack magnetic levitation by the Fourier series analysis which is utilized in the analysis of superconducting magnetic levitation. By using numerical examples considering a full‐scale car model, we reveal the features of the Inductrack system in comparison with the superconducting magnetic levitation. © 2002 Wiley Periodicals, Inc. Electr Eng Jpn, 142(1): 67–74, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.10061
Robust damping control of power oscillation incorporating parametric resonance
Authors: Watanabe Takao , Ohishi Junichi , Yasuda Keiichiro
Published: October 2002

In this paper we consider a damping control of low‐frequency oscillations in an electric power system. On the basis of the hypothesis that an auto‐parametric resonance model can explain a power oscillation, we propose a new model for a robust damping control, by which the system maintains stability even if some auto‐parametric resonance happens. With this model, we can express a parametric variation of a principal oscillation mode and a class of uncertainties which cover neglected dynamics. Since the model has a certain structure of uncertain parameters, we design a robust controller via µ‐synthesis. The robust controller which can be obtained from the presented design strategy has the property that the control performances are more sophisticated in comparison to controllers designed with other existing methods based on the H∞ control. © 2002 Wiley Periodicals, Inc. Electr Eng Jpn, 142(1): 42–49, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.10069
Turn‐off scheme of thyristor switches for network reconfiguration in FRIENDS
Authors: Hara Ryoichi , Kita Hiroyuki , Tanaka Eiichi , Hasegawa Jun , Iyoda Isao
Published: October 2002

The authors have proposed FRIENDS as a concept of the future electric power system. In order to realize FRIENDS, it is necessary to design the concrete interior structure and control scheme of the Quality Control Center (QCC) which is to be installed between distribution substation and customers. Hybrid‐type transfer switches are assumed to be installed on the high‐voltage side of the QCC to realize network reconfiguration. Some devices for handling power quality are also assumed to be installed on the low‐voltage side to realize customized power quality.

In this paper, a novel control scheme for shutoff of the thyristor switches by the power quality handling devices is proposed and the effectiveness of the proposed scheme is investigated through momentary analysis using PSCAD/EMTDC. © 2002 Wiley Periodicals, Inc. Electr Eng Jpn, 142(1): 32–41, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.10077
Design study of a high‐temperature superconducting transformer
Authors: Nagasawa Toru , Yamaguchi Mitsugi , Fukui Satoshi
Published: October 2002

Many research and development projects on high‐temperature superconducting apparatus such as a transformer, fault current limiter, and cable are being actively pursued in the power field as a result of performance improvement of Bi silver sheath high‐temperature superconducting (HTS) wire. HTS transformers are considered to be among the most promising applications in view of efficiency improvement, the interface with cryogenic cable and normal temperature devices, incombustibility, overload capability, the function as a reactor, and the possibility of use as a fault current limiter. The necessary technical development items of an HTS transformer in order to achieve performance superior to conventional devices are examined. For this purpose, three‐phase 66‐kV 100‐MVA transformers were designed for the comparison of an HTS transformer and a conventional one with oil cooling. The desirable development items are an HTS wire current density of about 40 A/mm2, an allowable winding strain of about 0.5%, a percent impedance of 7.5%, an air gap flux density of about 0.3 T, and AC losses of about 0.3 W/km‐A. © 2002 Wiley Periodicals, Inc. Electr Eng Jpn, 142(1): 25–31, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.10087
Evaluation of a power system stable region based on Hopf bifurcation theory
Authors: Watanabe Masayuki , Mitani Yasunori , Tsuji Kiichiro
Published: October 2002

A power system is a dynamic system, which includes several kinds of nonlinear elements. Transient stability is a typical example originating in the nonlinearity of power swing. On the other hand, use of the nonlinear analysis method based on Hopf bifurcation theory reveals the existence of a limit cycle around an operating point and the stability of the limit cycle. This paper evaluates power system global stability formed by an unstable limit cycle. The limit cycle mainly results from the excitation control. Therefore, it is important to consider the effect of flux linkage change in the field winding in addition to the δ‐ω variables. This paper presents a method of calculating the correct stability boundary associated with an unstable limit cycle. Some numerical results using a model power system demonstrate the accuracy of the method. © 2002 Wiley Periodicals, Inc. Electr Eng Jpn, 142(1): 16–24, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.10104
Extragenic suppressors of a dominant masculinizing her‐1 mutation in C. elegans identify two new genes that affect sex determination in different ways
Authors: Manser James , Wood William B. , Perry Marc D.
Published: October 2002

Summary: The her‐1 regulatory switch gene in C. elegans sex determination is normally active in XO animals, resulting in male development, and inactive in XX animals, allowing hermaphrodite development. The her‐1(n695gf) mutation results in the incomplete transformation of XX animals into phenotypic males. We describe four extragenic mutations that suppress the masculinized phenotype of her‐1(n695gf) XX. They define two previously undescribed genes, sup‐26 and sup‐27. All four mutations exhibit semidominance of suppression and by themselves have no visible effects on sex determination in otherwise genotypically wild‐type XX or XO animals. Analysis of interactions with mutations in the major sex‐determining genes show that sup‐26 and sup‐27 influence sex determination in fundamentally different ways. sup‐26 appears to act independently of her‐1 to negatively modulate synthesis or function of tra‐2 in both XX and XO animals. sup‐27 may play a role in X‐chromosome dosage compensation and influence sex determination indirectly. genesis 34:184–195, 2002. © 2002 Wiley‐Liss, Inc.
Rapid in vivo labeling of identified zebrafish neurons
Authors: Downes Gerald B. , Waterbury Julie A. , Granato Michael
Published: October 2002

We report a simple and rapid method to label individual neurons in live zebrafish embryos and to examine their gene expression profiles. Injection of plasmid DNA encoding an α‐tubulin promotor driving GFP expression results in mosaic embryos containing a limited number of GFP‐positive neurons. Labeled neurons express GFP in their soma and axon, providing the opportunity to analyze pathfinding behaviors of identified neurons in vivo. Moreover, the presence of only a small subset of GFP tagged neurons permits the rapid anatomical identification of these neurons based on soma position and axonal trajectory. Analysis of injected embryos reveals that most, if not all, spinal cord cell types and many other neuronal cell types elsewhere in the nervous system can be GFP tagged. Finally, by combining GFP labeling of individual neurons with fluorescent in situ hybridization, we demonstrate the potential of this method to elucidate gene expression patterns at single cell resolution. genesis 2:196–202, 2002. © 2002 Wiley‐Liss, Inc.