bluuebunny/crossref_metadata_2025_split huggingface dataset:
UBV and vbyβ stellar photometry in the eastern part of M31
Authors: Kurtev R.G. 
Published: April 2003

AbstractWe present UBV and the first vbyβ Strömgren stellar photometry in a field centered on the stellar association OB31 in the Eastern part of the Andromeda galaxy. The ages of the stellar populations are determined from the colormagnitude diagrams using the latest theoretical isochrones. HR diagram for all stars in the area is constructed. The mass of the brightest blue star is about 60ℳ︁⊙ and for the brightest red star is about 20ℳ︁⊙. The slope of the Stellar Initial Mass Function (IMF) for blue stars is –2.0±0.1 which is similar to that of other nearby galaxies.We investigate the stellar content of three van den Bergh associations as well as that of some new OB associations determined by cluster analysis. Ages of the van den Bergh associations are 4Myr for OB31 and 6Myr for OB32, OB34 and OB35. Eight blue supergiant candidates are isolated from the rest of the stars by using suitable color‐color diagrams in Strömgren system. The results from UBV and Strömgren uvby photometry are compared.
Statistical method for distance determination of a stellar group
Authors: Sharaf M.A. , Kamal F.Y. 
Published: April 2003

AbstractIn this paper, we developed statistical method for distance determination of a stellar group. The method depends on the assumption that, the stars scatter around a mean magnitude in a Gaussian distribution. The mean apparent magnitude of the stars is then expressed in terms of the frequency function of the apparent magnitudes, so as to correct for observational incompleteness at the faint end. The problem reduces to the solution of a highly transcendental equation for a given apparent magnitude parameter α. Computational algorithm of the method is illustrated and the numerical solutions of the basic equation are given for some values of α .
Metallicity distributions of globular cluster systems in galaxies
Authors: Eerik H. , Tenjes P. 
Published: April 2003

AbstractWe collected a sample of 100 galaxies for which different observers have determined colour indices of globular cluster candidates. The sample includes representatives of galaxies of various morphological types and different luminosities. Colour indices (in most cases (V–I), but also (B–I) and (C–T1)) were transformed into metallicities [Fe/H] according to a relation by Kissler‐Patig (1998). These data were analysed with the KMM software in order to estimate similarity of the distribution with uni‐ or bimodal Gaussian distribution. We found that 45 of 100 systems have bimodal metallicity distributions. Mean metallicity of the metal‐poor component for these galaxies is 〈[Fe/H]〉 = –1.40 ± 0.02, of the metalrich component 〈[Fe/H]〉 = –0.69 ± 0.03. Dispersions of the distributions are 0.15 and 0.18, respectively. Distribution of unimodal metallicities is rather wide. These data will be analysed in a subsequent paper in order to find correlations with parameters of galaxies and galactic environment.
Time‐series photometric spot modelling – VI. A new computer code and its application to 23 years of photometry of the active giant IM Pegasi
Authors: Ribárik G. , Oláh K. , Strassmeier K.G. 
Published: April 2003

AbstractWe present and apply a new computer program named SpotModeL to analyze single and multiple bandpass photometric data of spotted stars. It is based on the standard analytical formulae from Budding and Dorren. The program determines the position, size, and temperature of up to three spots by minimizing the fit residuals with the help of the Marquardt‐Levenberg non‐linear least‐squares algorithm. We also expand this procedure to full time‐series analysis of differential data, just as real observations would deliver. If multi‐bandpass data are available, all bandpasses can be treated simultaneously and thus the spot temperature is solved for implicitly. The program may be downloaded and used by anyone. In this paper, we apply our code to an ≈23 year long photometric dataset of the spotted RS CVn giant IM Peg. We extracted and modelled 33 individual light curves, additionally, we fitted the entire V dataset in one run. The resulting spot parameters reflect the long term light variability and reveal two active longitudes on the substellar point and on the antipode. The radius and longitude of the dominant spot show variations with 29.8 and 10.4 years period, respectively. Our multicolour data suggests that the spot temperature is increasing with the brightening of the star. The average spot temperature from V, IC is 3550 ± 150 K or approximately 900 K below the effective temperature of the star.
Black holes as parts of entangled systems
Authors: Basini G. , Capozziello S. , Longo G. 
Published: April 2003

AbstractA possible link between EPR‐type quantum phenomena and astrophysical objects like black holes, under a new general definition of entanglement, is established. A new approach, involving backward time evolution and topology changes, is presented bringing to a definition of the system black hole‐worm hole‐white hole as an entangled system.
Effect of food on gastrointestinal transit of liquids in cynomolgus monkeys
Authors: Kondo Hiromu , Watanabe Takashi , Yokohama Shigeharu , Watanabe Jun 
Published: April 2003

AbstractWe investigated the gastrointestinal transit of liquids, as well as various gastric pH profiles, in fed cynomolgus monkeys. Twelve grams of a biscuit‐type solid food were provided 1 h before the test. The acetaminophen method was used to determine the gastric half‐emptying time (t50%), which provided an estimate of the gastric emptying rate. The gastric emptying rate of liquids was significantly reduced after food intake in monkeys. The mean t50% value was 143.5 min and comparable to that of humans after eating. However, there was a large variability in the t50% between individual animals as shown by the coefficient of variance of approximately 80%. Next, the median oro‐caecal transit time in fed monkeys was determined to be 1.8 h, using the sulfasalazine‐sulfapyridine method. There was no significant difference in oro‐caecal transit time between unfed and fed monkeys; thus, food intake has no significant effect on the oro‐caecal transit time of liquids in either monkeys or humans. However, the oro‐caecal transit time in humans is about 2 h longer than that in monkeys. Our experiments using several different foods suggested that the typical human gastric pH profile could not be simulated in fed monkeys. Copyright © 2003 John Wiley & Sons, Ltd.
Does stereoselective lymphatic absorption contribute to the enantioselective pharmacokinetics of halofantrine In Vivo?
Authors: Shackleford David M. , Porter Christopher J. H. , Charman William N. 
Published: April 2003

AbstractHalofantrine (Hf) is a chiral, lipophilic phenanthrene methanol antimalarial which exhibits both enantioselective plasma pharmacokinetics and extensive lymphatic absorption when administered postprandially. In order to determine whether enantioselective lymphatic absorption contributes to the previously reported enantioselective pharmacokinetics of Hf, lymph samples collected from thoracic duct‐cannulated dogs dosed with racemic Hf (100 mg, administered postprandially) were assayed with a chiral HPLC method capable of quantifying the relative amounts of (+)‐ and (−)‐Hf. During the period when the majority (>95%) of Hf transport into lymph occurred (0–5 h post dose), essentially equal amounts of the two enantiomers were present in the intestinal lymph. At later times (e.g. 5–12 h post dose), there was a steady increase in the fraction of (+)‐Hf present in lymph. The trends evident at later time points most likely reflect an increase in the proportion of (+)‐Hf present in systemic blood, (resulting from enantioselective systemic metabolism) and a corresponding increase in (+)‐Hf in the thoracic lymph by equilibration of drug across blood and lymphatic capillaries, as opposed to enantioselective lymphatic transport per se. This study was the first to examine the possibility of stereoselectivity in lymphatic transport, however, the data suggest that drug absorption (at least in the case of halofantrine) via the intestinal lymphatics is not enantioselective. Copyright © 2003 John Wiley & Sons, Ltd.
Interfacial effect of extremely low frequency electromagnetic fields (EM‐ELF) on the vaporization step of carbon dioxide from aqueous solutions of body simulated fluid (SBF)
Authors: Beruto D.T. , Botter R. , Perfumo F. , Scaglione S. 
Published: April 2003

AbstractSpontaneous processes in an aqueous solution of body simulated fluid (SBF) were monitored in closed vessel for a period of 1 month at 310 K, at atm pressure, and initial pH of 7.2, both with and without exposure to a square pulsed extremely low frequency electromagnetic fields (EM‐ELF) of 250 μT, repeated at 75 Hz. The most important findings are that the SBF surface tension (γ), evaluated under the EM‐ELF field, is lower than the corresponding value measured without EM‐ELF at any time. Furthermore, the pH of the exposed SBF is always more basic than that of the unexposed solution. As a consequence, when the EM‐ELF is applied, calcium phosphate salts do not precipitate from the SBF solution for a period as long as 30 days. Behind all these experimental evidences there is only one mechanism: the vaporisation from the SBF‐air interface of the CO2(aq) dissolved into the aqueous electrolyte solution. Thermodynamic analysis of these results establish that, at any given time, the difference, Δ, between the measured surface tensions with and without EM‐ELF applied, gives the work of the electromagnetic forces to change the extent at which the CO2(aq) adsorbs at the liquid‐air interface. It has been demonstrated that the work supply per second and per unit of area by the electromagnetic forces, 3.73 × 10−10 mJ/s cm2, is very near to the experimental slope in the plot Δ vs. t 1.7 × 10−10 mJ/s cm2. This leads to the conclusion that the EM‐ELF fields have an interfacial effect on the concentration value of the CO2 (aq) at the SBF‐air interface. Because of that, the EM‐ELF field is enhancing the CO2 vaporisation rate; thus any other steps, which are a consequence of this mechanism, are changing. These results allow explanation of previous experiments concerning the precipitation of calcium carbonate from flowing hydrogen carbonate aqueous solution in the temperature range 353–373 K at a pressure of 0.1 MPa under the effect of static magnetic fields. Bioelectromagnetics 24:251‐261, 2003. © 2003 Wiley‐Liss, Inc.
No influence of magnetic fields on cell cycle progression using conditions relevant for patients during MRI
Authors: Schiffer Ilka B. , Schreiber Wolfgang G. , Graf Robert , Schreiber Elke M. , Jung Detlev , Rose Dirk M. , Hehn Manfred , Gebhard Susanne , Sagemüller Jens , Spieß Hans W. , Oesch Franz , Thelen Manfred , Hengstler Jan G. 
Published: April 2003

AbstractThe purpose of this study was to examine whether exposure to magnetic fields (MFs) relevant for magnetic resonance imaging (MRI) in clinical routine influences cell cycle progression in two tumor cell lines in vitro. HL60 and EA2 cells were exposed to four types of MFs: (i) static MF of 1.5 and 7.05 T, (ii) extremely low frequency magnetic gradient fields (ELFMGFs) with ± 10 mT/m and 100 Hz, as well as ± 100 mT/m and 100 Hz, (iii) pulsed high frequency MF in the radiofrequency (RF) range (63.6 MHz, 5.8 μT), and (iv) a combination of (i–iii). Exposure periods ranged from 1 to 24 h. Cell cycle distribution (G0/G1, S, and G2/M phases) was analyzed by flow cytometry. Cell cycle analysis did not reveal differences between the exposed and the control cells. As expected, positive controls with irradiated (8 Gy) HL60 and EA2 cells showed a strong G2/M arrest. Using conditions that are relevant for patients during MRI, no influence of MFs on cell cycle progression was observed in these cell lines. Care was taken to control secondary parameters of influence, such as vibration by the MR scanner or temperature to avoid false positive results. Bioelectromagnetics 24:241‐250, 2003. © 2003 Wiley‐Liss, Inc.
1439 MHz pulsed TDMA fields affect performance of rats in a T‐maze task only when body temperature is elevated
Authors: Yamaguchi Hironori , Tsurita Giichirou , Ueno Shoogo , Watanabe Soichi , Wake Kanako , Taki Masao , Nagawa Hirokazu 
Published: April 2003

AbstractThis study sought to clarify the effects of exposure to electromagnetic waves (EMW) used in cellular phones on learning and memory processes. Sprague–Dawley rats were exposed for either 1 h daily for 4 days or for 4 weeks to a pulsed 1439 MHz time division multiple access (TDMA) field in a carousel type exposure system. At the brain, average specific absorption rate (SAR) was 7.5 W/kg, and the whole body average SAR was 1.7 W/kg. Other subjects were exposed at the brain average SAR of 25 W/kg and the whole body average SAR of 5.7 W/kg for 45 min daily for 4 days. Learning and memory were evaluated by reversal learning in a food rewarded T‐maze, in which rats learned the location of food (right or left) by using environmental cues. The animals exposed to EMW with the brain average SAR of 25 W/kg for 4 days showed statistically significant decreases in the transition in number of correct choices in the reversal task, compared to sham exposed or cage control animals. However, rats exposed to the brain average SAR of 7.5 W/kg for either 4 days or for 4 weeks showed no T‐maze performance impairments. Intraperitoneal temperatures, as measured by a fiber optic thermometer, increased in the rats exposed to the brain average SAR of 25 W/kg but remained the same for the brain average SAR of 7.5 W/kg. The SAR of a standard cellular phone is restricted to a maximum of 2 W/kg averaged over 10 g tissue. These results suggest that the exposure to a TDMA field at levels about four times stronger than emitted by cellular phones does not affect the learning and memory processes when there are no thermal effects. Bioelectromagnetics 24:223–230, 2003. © 2003 Wiley‐Liss, Inc.
Effects of 50 Hz magnetic fields on fMLP‐induced shape changes in invertebrate immunocytes: The role of calcium ion channels
Authors: Gobba Fabriziomaria , Malagoli Davide , Ottaviani Enzo 
Published: April 2003

AbstractPlasma membrane Ca2+ channels in immunocytes from the mussel Mytilus galloprovincialis exposed to 50 Hz sine wave magnetic fields (MFs) of various strengths were studied. At levels of 300 μT and above, MFs reduce shape changes in immunocytes induced by the chemotactic substance N‐formyl‐Meth‐Leu‐Phe, and this effect involves L‐type Ca2+ channels. Upon the addition of the Ca2+ blocker verapamil to molluscan immunocytes exposed to MFs results in a synergistic cytotoxic action, while in the presence of the Ca2+ opener SDZ‐202, 791, a reactivation of the cells is observed. This suggests that, as previously reported for potassium channels, the damage to Ca2+ channels induced by short exposure to MF at appropriate intensities is not permanent. Bioelectromagnetics 24:277–282, 2003. © 2003 Wiley‐Liss, Inc.
Radio frequency electromagnetic field exposure in humans: Estimation of SAR distribution in the brain, effects on sleep and heart rate
Authors: Huber Reto , Schuderer Jürgen , Graf Thomas , Jütz Kathrin , Borbély Alexander A , Kuster Niels , Achermann Peter 
Published: April 2003

AbstractIn two previous studies we demonstrated that radiofrequency electromagnetic fields (RF EMF) similar to those emitted by digital radiotelephone handsets affect brain physiology of healthy young subjects exposed to RF EMF (900 MHz; spatial peak specific absorption rate [SAR] 1 W/kg) either during sleep or during the waking period preceding sleep. In the first experiment, subjects were exposed intermittently during an 8 h nighttime sleep episode and in the second experiment, unilaterally for 30 min prior to a 3 h daytime sleep episode. Here we report an extended analysis of the two studies as well as the detailed dosimetry of the brain areas, including the assessment of the exposure variability and uncertainties. The latter enabled a more in depth analysis and discussion of the findings. Compared to the control condition with sham exposure, spectral power of the non‐rapid eye movement sleep electroencephalogram (EEG) was initially increased in the 9–14 Hz range in both experiments. No topographical differences with respect to the effect of RF EMF exposure were observed in the two experiments. Even unilateral exposure during waking induced a similar effect in both hemispheres. Exposure during sleep reduced waking after sleep onset and affected heart rate variability. Exposure prior to sleep reduced heart rate during waking and stage 1 sleep. The lack of asymmetries in the effects on sleep EEG, independent of bi‐ or unilateral exposure of the cortex, may indicate involvement of subcortical bilateral projections to the cortex in the generation of brain function changes, especially since the exposure of the thalamus was similar in both experiments (approx. 0.1 W/kg). Bioelectromagnetics 24:262‐276, 2003. © 2003 Wiley‐Liss, Inc.
Effect of a 902 MHz electromagnetic field emitted by mobile phones on human cognitive function: A replication study
Authors: Haarala Christian , Björnberg Linda , Ek Maria , Laine Matti , Revonsuo Antti , Koivisto Mika , Hämäläinen Heikki 
Published: April 2003

AbstractOur study was a replication and extension with methodological improvements to a previous study on effects of the electromagnetic field (EMF) emitted by a 902 MHz mobile phone on human cognitive functioning. Improvements on the previous study included multicentre testing and a double blind design. A total of 64 subjects (32 men and 32 women) in two independent laboratories performed a battery of 9 cognitive tasks twice: while the EMF was on and while it was off. Reaction times (RTs) and accuracy were recorded. The order of exposure and tasks was counterbalanced across subjects and gender. There were no statistically significant differences in performance between genders or laboratories. Although the RTs and the accuracy of answers were very similar to those of our previous study, our previous results were not replicated. We concluded that EMF had no effect on RTs or on the accuracy of the subjects' answers. Further, our results indicate that our EMF had no immediate effect on human cognitive functioning or that such effects are so small that they are observed on behavior only occasionally. Bioelectromagnetics 24:283–288, 2003. © 2003 Wiley‐Liss, Inc.
Mouse circadian rhythm before the Kobe earthquake in 1995
Authors: Yokoi Sayoko , Ikeya Motoji , Yagi Takeshi , Nagai Katsuya 
Published: April 2003

AbstractMouse circadian diagrams recorded at Osaka University showed unusual mouse behavior before the Kobe earthquake on January 17th, 1995. The locomotive activities on January 16th showed drastic increases, several times above the standard deviation, during both sleep and active periods, indicating that mice perceived of some preseismic signals. Bioelectromagnetics 24:289–291, 2003. © 2003 Wiley‐Liss, Inc.
Developmental toxicity evaluation of ELF magnetic fields in Sprague–Dawley rats
Authors: Chung Moon‐Koo , Kim Jong‐Choon , Myung Sung‐Ho , Lee Dong‐Il 
Published: April 2003

AbstractTo identify possible effects of horizontally polarized magnetic field (MF) exposure on maintenance of pregnancy and embryo‐fetal development, an MF exposure system was designed and constructed and 96 time‐mated female Sprague–Dawley (SD) rats (24/group) received continuous exposure to 60 Hz MF at field strengths of 0 (sham control) and 5, 83.3, or 500 μT (50, 833, or 5000 mG). Dams received MF or sham exposures for 22 h/day on gestational day 6–20. MF was monitored continuously throughout the study. There were no evidences of maternal toxicity or developmental toxicity in any MF exposed groups. Mean maternal body weight, organ weights, and hematological and serum biochemical parameters in groups exposed to MF did not differ from those in sham control. No exposure related differences in fetal deaths, fetal body weight, and placental weight were observed between MF exposed groups and sham control. External, visceral, and skeletal examination of fetuses demonstrated no significant differences in the incidence of fetal malformations between MF exposed and sham control groups. In conclusion, exposure of pregnant rats to 60 Hz at MF strengths up to 500 μT during gestation day 6–20 did not produce any biologically significant effect in either dams or fetuses. Bioelectromagnetics 24:231‐240, 2003. © 2003 Wiley‐Liss, Inc.
Community College Roles in Teacher Education: Current Approaches and Future Possibilities
Authors: Townsend Barbara K. , Ignash Jan M. 
Published: April 2003

AbstractThis chapter examines the current role of community colleges in preservice and in‐service teacher education, including the development of the associate of arts degree in teacher education, the community college baccalaureate in teacher education, and alternative certification programs. Factors influencing future trends and predictions and recommendations about the community college's future role are also discussed.
Predominantly σ‐Bonded Metal Carbonyl Cations (σ‐Carbonyls): New Synthetic, Structural, and Bonding Concepts in Metal Carbonyl Chemistry
Authors: Willner Helge , Aubke Friedhelm 
Published: April 2003

AbstractPredominantly σ‐bonded metal carbonyl cations (σ‐carbonyls) are conveniently generated in the Lewis superacid SbF5 or the conjugate Brønsted–Lewis superacid HFSbF5, primarily by solvolytic or reductive carbonylations. Thermally stable salts are formed with the fluoroantimonate(V) ions [SbF6]− and [Sb2F11]−. The salts are characterised by analytical, structural, spectroscopic and computational methods. Most homoleptic carbonyl cations have very regular geometries, comensurate with their d‐electron configurations: linear (d10), square planar (d8) or octahedral(d6). The cations with metals in oxidation states of +2 or +3 are termed “superelectrophilic”. Extended molecular structures form by significant interionic CF contacts with electrophilic carbon as acceptor. To account for all experimental observations, a conceptually simple synergetic bonding model is proposed. An outlook at anticipated future developments based on very recent results is provided.
Hexacyanometalate Molecular Chemistry: Heptanuclear Heterobimetallic Complexes; Control of the Ground Spin State
Authors: Marvaud Valérie , Decroix Caroline , Scuiller Ariane , Guyard‐Duhayon Carine , Vaissermann Jacqueline , Gonnet Florence , Verdaguer Michel 
Published: April 2003

AbstractFollowing a bottom‐up approach to nanomaterials, we present a rational synthetic route from hexacyanometalates [M(CN)6]3− (M=CrIII, CoIII) cores to well‐defined heptanuclear complexes. By changing the nature of the metallic cations and using a localised orbital model it is possible to control and to tune the ground state spin value. Thus, with M=CrIII, d3, S=3/2, three heptanuclear species were built and characterised by mass spectrometry in solution, by single‐crystal X‐ray diffraction and by powder magnetic susceptibility measurements, [CrIII(CNM′Ln)6]9+ (M′=CuII, NiII, MnII, Ln=polydentate ligand), showing spin ground states SG=9/2 [CuII], with ferromagnetic interactions JCr,Cu=+45 cm−1, SG=15/2 [NiII] and JCr,Ni=+17.3 cm−1, SG=27/2 [MnII], with an antiferromagnetic interaction JCr,Mn=−9 cm−1, (interaction Hamiltonian ℋ︁=−JCr,M [SCrΣiSM(i)], i=1–6). With M=CoIII, d6, S=0, the heptanuclear analogues [CoIII(CN−M′Ln)6]9+ (M′=CuII, NiII, MnII) were similarly synthesised and studied. They present a singlet ground state and allow us to evaluate the weak antiferromagnetic coupling constant between two next‐nearest neighbours M′CoM′.