bluuebunny/crossref_metadata_2025 huggingface dataset:
Doppler assessment of fetal aortic isthmus blood flow in two different sonographic planes during the second half of gestation
Authors: Del Río M. , Martínez J. M. , Figueras F. , Bennasar M. , Palacio M. , Gómez O. , Coll O. , Puerto B. , Cararach V.
Published: July 2005

Objective

To compare the reliability of Doppler blood flow measurements of the fetal aortic isthmus (AoI) according to whether the sampling plane is obtained from the traditional longitudinal aortic arch (LAA) view or the more recently described three vessels and trachea (3VT) view of the fetal upper mediastinum.

Methods

Doppler blood flow measurements of pulsatility index (PI), resistance index (RI), peak systolic (PSV), end‐diastolic (EDV) and time‐averaged maximum (TAMXV) velocities were performed in the AoI of 40 fetuses between 24 and 36 weeks of gestation. All measurements were sampled in two different sonographic planes of the AoI: the LAA view, at a few millimeters beyond the origin of the left subclavian artery, and the 3VT view, just before the V‐shaped junction of the aortic and ductal arches. All scans were performed by the same observer. The reliability of Doppler blood flow measurements was assessed by calculating intraclass correlation coefficients (ICCs) and limits of agreement between the two different sonographic sites evaluating the AoI.

Results

Mean values of PI, RI, PSV, EDV and TAMXV were similar in the LAA and 3VT views. The PI and vascular velocities were reliably measured from both sonographic sites. ICCs for variability of measurements were 0.78, 0.63, 0.63, 0.60 and 0.55 for PI, RI, PSV, EDV and TAMXV, respectively. Limits of agreement revealed minimal disagreement between the two sites of evaluation of the AoI for all measurements.

Conclusions

On the basis of our observations, Doppler blood flow measurements across the fetal AoI can be reliably obtained from both the 3VT and the traditional LAA sonographic views. Since the transverse upper thoracic 3VT plane is achievable in most fetal positions, Doppler study of the AoI appears to be easier than expected. Copyright © 2005 ISUOG. Published by John Wiley & Sons, Ltd.
Ethnic differences in prenatal growth and the association with maternal and fetal characteristics
Authors: Drooger J. C. , Troe J. W. M. , Borsboom G. J. J. M. , Hofman A. , Mackenbach J. P. , Moll H. A. , Snijders R. J. M. , Verhulst F. C. , Witteman J. C. M. , Steegers E. A. P. , Joung I. M. A.
Published: July 2005

Objectives

The objectives of this study were to determine ethnic differences in prenatal growth and to examine their association with differences in maternal and fetal characteristics such as maternal height, weight, age, parity and fetal gender.

Methods

A total of 1494 women from Rotterdam, The Netherlands, with a low‐risk pregnancy who participated in a population‐based cohort study, the Generation R Study, were offered three ultrasound examinations during pregnancy. Multilevel modeling was applied to determine ethnic differences in (estimated) fetal weight (including birth weight) and in the separate biometric variables that were used to calculate the estimated fetal weight (abdominal circumference, head circumference and femur length). Additionally the association of ethnic differences with maternal and fetal characteristics (i.e. maternal weight, height, age, parity and fetal gender) was studied.

Results

Turkish, Cape Verdian, Surinamese‐Creole and Surinamese‐Hindustani women had on average smaller fetuses than the native Dutch women. The differences became more pronounced towards term. In the Turkish group the differences were no longer statistically significant when adjusted for maternal weight, height, age, parity and fetal gender. In the Cape Verdian, Surinamese‐Creole and Surinamese‐Hindustani groups the differences decreased after adjustment (31%, 16% and 39%, respectively).

Conclusions

This study shows that there are ethnic differences in fetal growth, which to a large extent may be attributed to differences in maternal weight, height, age and parity. For some ethnic groups, however, additional factors are involved, as differences remain significant after correction for fetal and maternal characteristics. Copyright © 2005 ISUOG. Published by John Wiley & Sons, Ltd.
On‐line analysis of chrome–iron ores on a conveyor belt using x‐ray fluorescence analysis
Authors: Sokolov A. D. , Docenko D. , Bliakher E. , Shirokobrod O. , Koskinen Juha
Published: July 2005

We describe the method for and results of the application of an EDXRF on‐line analyzer for the analysis and quality testing of chrome–iron ores. For this task we used a BSI‐2000 analyzer for measurement of lumpy material being transported by a conveyor belt. The task of fully automated quantitative analysis of material on a conveyor belt is not very simple, as the results of measurements should not depend significantly on many factors, such as the distance to the measured material, the lump size, unknown and changing amounts of elements unseen by the analyzer; air and material humidity and ambient temperature. To solve most of these problems we used the program AssayKit for elemental and molecular composition calculation based on the fundamental parameters method. The chosen configuration of the x‐ray tube illumination cone and the detector registration cone allows measurements to be made at a wide range of distances between the analyzer and material. The XRF analyzer with this program was successfully applied to chrome–iron ore analysis in Kemi mine, Finland, for quality control of outgoing production. The accuracy of analysis—standard deviation of 1.1% for chrome and 0.8% for iron in full operation—was verified by more than 300 comparisons with chemical analysis measurements. Copyright © 2005 John Wiley & Sons, Ltd.
Intraneuronal investigations of organic components and trace elements with the use of synchrotron radiation
Authors: Szczerbowska‐Boruchowska M. , Chwiej J. , Lankosz M. , Adamek D. , Wojcik S. , Krygowska‐Wajs A. , Tomik B. , Bohic S. , Susini J. , Simionovici A. , Dumas P. , Kastyak M.
Published: July 2005

Three techniques based on synchrotron radiation microbeam analysis were applied to biochemical investigations of human central nervous system (CNS) tissue. Thin tissue slices representing Parkinson's disease (PD), amyotrophic lateral sclerosis (ALS) and control cases were studied. Synchrotron radiation microbeam x‐ray fluorescence (micro‐SRXRF) was applied to the analysis of the elemental distribution inside single nerve cells. Investigation of copper oxidation state was performed with the use of micro x‐ray absorption near‐edge structure spectroscopy (micro‐XANES). Moreover, the organic components of the tissues were analyzed by means of synchrotron radiation Fourier transform infrared microspectroscopy (SR‐FTIRM). Topographic differences in elemental composition were observed for the nerve cell body. Higher levels of Fe, Zn and Ca were found for the neurons of PD cases in comparison with the control group. The IR spectra measured in neurons of PD, ALS and control cases showed differences in absorption bands associated with characteristic groups of selected biological molecules. Additionally, results of SR‐FTIRM measurements indicated inhomogeneous accumulation of the main organic components in PD nerve cells, in contrast to the control cases. Copyright © 2005 John Wiley & Sons, Ltd.
Regulation of uncoupling protein activity in phosphorylating potato tuber mitochondria
Authors: Navet Rachel , Douette Pierre , Puttine-Marique Florence , Sluse-Goffart Claudine M. , Jarmuszkiewicz Wieslawa , Sluse Francis E.
Published: July 2005

In isolated potato tuber mitochondria, palmitic acid (PA) can induce a H+ leak inhibited by GTP in the phosphorylating (state 3) respiration but not in the resting (state 4) respiration. The PA‐induced H+ leak is constant when state 3 respiration is decreased by an inhibition of the succinate uptake with n‐butyl malonate (nBM). We show that the efficiency of inhibition by GTP is decreased when state 3 respiration is progressively inhibited by antimycin A (AA) and is restored following subsequent addition of nBM. We propose that in phosphorylating potato tuber mitochondria, the redox state of ubiquinone, which can antagonistically be varied with AA and nBM, modulates inhibition of the PA‐activated UCP‐sustained H+ leak by GTP.
In vitro selection of DNA binding sites for ABF1 protein from Saccharomyces cerevisiae
Authors: Beinoravičiūtė-Kellner Rasa , Lipps Georg , Krauss Gerhard
Published: July 2005

The autonomously replicating sequence‐binding factor 1 (ABF1) from Sacchramoyces cerevisiae is known as a multifunctional DNA binding protein that is involved in transcriptional regulation, DNA‐replication, and in restructuring of chromatin via nucleosome remodelling. ABF1 binds to DNA sequences found in ARS elements and in various transcriptional regulatory elements. This led to the early definition of the consensus motive 5′‐CGTnnnnnnnGA(G/C)‐3′. We have used a SELEX approach to expand and better characterize the DNA sequence requirements of ABF1. Starting from a pool of oligonucleotides randomized at a sequence of 30 nucleotides, we used EMSA to select for sequences with high affinity for ABF1. We obtained the sequences of 106 aptamers after the 15th SELEX round. A 16 nucleotide consensus was derived from this pool by analysis with the motif search programme MEME. Quantitative EMSA experiments verified our experimental approach since binding sequences which were bound with high affinity occurred more often in the pool and resembled the derived consensus to a higher degree. We found DNA sequences that are bound by ABF1 with nearly two‐magnitude higher affinity as compared to the hitherto accepted ABF1 consensus sequence. This led us to postulate a strong recognition motive: 5′‐TnnCGTnnnnnnTGAT‐3′.
Genetically modified mouse models to study the role of metastasis-promoting S100A4(mts1) protein in metastatic mammary cancer
Authors: Ambartsumian Noona , Grigorian Mariam , Lukanidin Eugene
Published: July 2005

Transgenic and knockout mouse models are extensively used to study the mechanisms of tumour formation. The availability of mouse models to study metastatic spread of tumours is although quite limited. S100A4(mts1), that belongs to the S100 family of Ca-binding proteins, has been shown to function as a metastasis-promoting protein. We generated strains of mice with modified expression of S100A4 in order to understand the mechanism by which S100A4 protein stimulates metastatic spread of the tumour cells. Transgenic mice over-expressing the S100A4 gene in the mammary gland were crossed with GRS/A mice, characterized by a high incidence of spontaneous non-metastatic mammary tumours. The resulting hybrid mice developed metastatic tumours. Transgenic mice with ubiquitous expression of S100A4 developed vascular tumours, hemangiomas and contained enhanced levels of the S100A4 protein in the blood. Based on these observations we demonstrated that extracellular S100A4 functions as an angiogenic factor. Study of tumour development in the S100A4 – deficient mouse model demonstrated key role of extracellular S100A4 in stimulation of tumour development and metastasis formation.
Gene expression of factors related to the immune reaction in response to intramammary Escherichia coli lipopolysaccharide challenge
Authors: Bruckmaier Rupert M.
Published: July 2005

Pathogenic microorganisms invading the mammary gland induce an inflammatory reaction which includes an increase of somatic cells in milk and activation of bacteriostatic enzymes and proteins in milk. During spontaneously occurring subclinical mastitis the somatic milk cells, mainly macrophages, secrete cytokines, eicosanoids, acute phase proteins and other immunomediators. In contrast, the bacteriostatic protein lactoferrin is mainly secreted by mammary epithelial tissue, while major milk proteins like α-lactalbumin and κ-casein are down-regulated already during subclinical infection.

Changes of the mRNA expression of various immunomediators in the mammary tissue of cows during 12 h after induction of mastitis via intramammary administration of lipopolysaccharide (LPS) in several studies are reported. Six healthy lactating cows were injected in one quarter with 100 μg Escherichia coli-LPS (O26[ratio ]B6) and the contralateral quarter with saline (9 g/l) serving as control. mRNA expression in mammary biopsy samples of various inflammatory factors and milk proteins at 0, 3, 6, 9 and 12 h after LPS administration was quantified by real-time reverse transcription-PCR.

In LPS-challenged quarters tumour necrosis factor α and cyclooxygenase-2 mRNA expression increased to their highest values (P<0·05) at 3 h after LPS-challenge. Expression of lactoferrin, lysozyme, inducible nitric oxide synthase, and of the apoptotic factors caspase-3, caspase-7 and FAS was elevated (P<0·05) and peaked at 6 h after challenge. No significant increase in mRNA expression of platelet-activating factor acethylhydrolase, 5-lipoxygenase, and insulin-like growth factor 1 was found. None of the parameters tested did change significantly in the control quarters. mRNA expression of major milk proteins did not change significantly in response to the LPS challenge (αS1-casein, αS2-CN, β-CN and β-lactoglobulin) except for α-lactalbumin which decreased (P<0·05) in LPS-treated and control quarters and for κ-CN which decreased in the LPS-treated quarters. In conclusion, mRNA expression of the majority albeit not all inflammatory factors changed within hours of LPS challenge. Decreased gene expression of α-lactalbumin and κ-CN may reduce milk yield and suitability for cheese production.
Nerve Growth Factor mediates its pro-invasive effect in parallel with the release of a soluble E-cadherin fragment from breast cancer MCF-7/AZ cells
Authors: Dollé Laurent , Oliveira Maria-José , Bruyneel Erik , Hondermarck Hubert , Bracke Marc
Published: July 2005

To define better the function of Nerve Growth Factor (NGF) in breast cancer progression, we investigated whether this polypeptide was able to induce breast cancer cell invasion. NGF inhibited aggregation of tumour cells through modulation of the E-cadherin/catenin complex function. In addition, NGF induced the breast cancer cells to invade into Matrigel. We focused our attention on how NGF prevents aggregation, in order to discover the signalling pathway that leads tumour cells to acquire the invasive phenotype. Moreover, studies on the identification of signalling pathways that are responsive for NGF-induced invasion will be basically described.
Antimicrobial resistance in Campylobacter jejuni from humans and broilers in Norway
Authors: NORSTRÖM M. , HOFSHAGEN M. , STAVNES T. , SCHAU J. , LASSEN J. , KRUSE H.
Published: July 2005

In this study comprising isolates from 2001 to 2003, resistance was considerably more widespread among Campylobacter jejuni from humans infected abroad than infected within Norway. The discrepancy was particularly notable for fluoroquinolone resistance (67·4% vs. 6·5%). This is probably a reflection of a low resistance prevalence in Norwegian broiler isolates (1·2% fluoroquinolone resistant).
Seroprevalence of IgG antibodies to SARS-coronavirus in asymptomatic or subclinical population groups
Authors: LEUNG G. M. , LIM W. W. , HO L.-M. , LAM T.-H. , GHANI A. C. , DONNELLY C. A. , FRASER C. , RILEY S. , FERGUSON N. M. , ANDERSON R. M. , HEDLEY A. J.
Published: July 2005

We systematically reviewed the current understanding of human population immunity against SARS-CoV in different groups, settings and geography. Our meta-analysis, which included all identified studies except those on wild animal handlers, yielded an overall seroprevalence of 0·10% [95% confidence interval (CI) 0·02–0·18]. Health-care workers and others who had close contact with SARS patients had a slightly higher degree of seroconversion (0·23%, 95% CI 0·02–0·45) compared to healthy blood donors, others from the general community or non-SARS patients recruited from the health-care setting (0·16%, 95% CI 0–0·37). When analysed by the two broad classes of testing procedures, it is clear that serial confirmatory test protocols resulted in a much lower estimate (0·050%, 95% CI 0–0·15) than single test protocols (0·20%, 95% CI 0·06–0·34). Potential epidemiological and laboratory pitfalls are also discussed as they may give rise to false or inconsistent results in measuring the seroprevalence of IgG antibodies to SARS-CoV.
Epidemiological characteristics ofSalmonellaTyphimurium isolated from animals and feed in Poland
Authors: WASYL D. , SANDVANG D. , SKOV M. N. , BAGGESEN D. L.
Published: July 2005

Fifty-sevenSalmonellaTyphimurium strains isolated from poultry, swine and animal feed in Poland during the years 1979–1998 and 2000–2002 were analysed with conventional and molecular techniques. Antimicrobial resistance as well as multiresistance was found, respectively, in 80·1% and 56·1% of the isolates and most frequently among isolates from 2000–2002. Of several phage types noted, DT104 was prevalent among poultry, swine and feed isolates. DT104, U302 and non-typable strains had a multiple resistant profile (ACSSuT) due to the presence of class I integrons. Pulse-field gel electrophoresis ofXbaI andBlnI digest showed high genomic similarity between the strains and confirmed clonal spread ofS. Typhimurium infections. Plasmid profiling allowed further differentiation of the strains. We have, therefore, confirmed the appearance ofS. Typhimurium DT104 showing genome integrated integron-mediated antimicrobial resistance in Poland. These findings are significant for public and animal health risks and document the dissemination of DT104 epidemic strains into new geographical regions.
Three‐dimensional fluid simulations of plasma asymmetries in the Martian magnetotail caused by the magnetic anomalies
Authors: Harnett E. M. , Winglee R. M.
Published: July 2005

Three‐dimensional single fluid nonideal MHD simulations of the solar wind interaction with Mars show that the strong magnetic anomalies in the Southern Hemisphere of Mars cause asymmetries in the near tail plasma. The simulations were run with the strong southern magnetic anomalies (SSMA) facing midnight, dawn, or dusk. The interplanetary magnetic field (IMF) was set to 1 nT in the By direction. The steady state results were then compared to the case when no surface magnetic field is present. The comparisons show regions of plasma depletion of ∼60% and enhanced plasma densities of over 200% for different SSMA orientations. The depleted plasma regions are similar to the plasma voids detected by Mars Global Surveyor. A minimagnetopause forms inside the magnetic pileup boundary for all three cases. When the SSMA are at the dusk terminator, the IMF drapes over dipole‐like surface magnetic fields, creating a magnetic field geometry reminiscent of a closed magnetosphere at Earth. When the SSMA are at dawn, the magnetic field geometry resembles that of an open magnetosphere at Earth, as the IMF reconnects substantially to the surface magnetic field. The complex magnetic field geometry for all three cases presented leads to large‐scale modification of the plasma flow in the tail.
Global structure of Jupiter's magnetospheric current sheet
Authors: Khurana Krishan K. , Schwarzl Hannes K.
Published: July 2005

Jupiter's magnetosphere contains a gigantic sheet‐like structure located near its dipole magnetic equator that contains most of the plasma and energetic particles swirling in Jupiter's magnetosphere. Called the “current sheet,” it behaves like a rigid structure inside a radial distance of ∼50 RJ where the periodic reversals of the Br component are highly predictable. Beyond a radial distance of ∼25 RJ, the tilted current sheet lags behind the dipole magnetic equator in proportion to the radial distance of the observer. On the nightside, at radial distances >50 RJ, the current sheet is seen to become parallel to the solar wind flow direction. In this work, we analyze magnetic field observations from all six spacecraft that have explored Jupiter's magnetosphere (Pioneers 10 and 11, Voyagers 1 and 2, Ulysses, and Galileo) to determine the global structure of Jupiter's current sheet. We have assembled a database of 6328 current sheet crossings by using an automated procedure which utilizes reversals in the radial component of the magnetic field to identify current sheet crossings. The assembled database of current sheet crossings spans all local times in Jupiter's magnetosphere under differing solar wind conditions. The new model is based on a further generalization of the hinged‐magnetodisc models of Behannon et al. (1981) and Khurana (1992). Four new features of the improved model are that (1) close to Jupiter, the prime meridian of the current sheet (the azimuthal direction in which it attains its highest inclination) is found to be shifted by 2.2° from the VIP4 model current sheet (Connerney et al., 1998). (2) In addition to the delay caused by the wave travel time, the location of the current sheet is further delayed because of the sweep‐back of the field lines. (3) The signal delay associated with wave propagation is seen to vary both with radial distance and local time, and (4) the current sheet is allowed to become parallel to the solar wind direction at large distances in the magnetotail in agreement with the observations. The new model is much superior at predicting current sheet crossing times than previously published models (especially in the midnight and dusk sectors). The RMS error of fit between the modeled and observed current sheet crossing longitudes is 19.3°. A comparison of the new model with previous models is presented.
Modeling the structure and variability of the southern Benguela upwelling using QuikSCAT wind forcing
Authors: Blanke Bruno , Speich Sabrina , Bentamy Abderrahim , Roy Claude , Sow Bamol
Published: July 2005

The structure and patterns of variability of the southern Benguela coastal upwelling system are investigated with a high‐resolution regional model forced by QuikSCAT winds over 1999–2003. The relevance of this global wind product is tested, at first, for the specific nearshore southeast Atlantic; then, the wind products are spatially or temporally degraded from the original 0.5° daily fluxes and are used to diagnose the main scales of the surface dynamical forcing variability. Time resolution appears as a crucial factor in the wind stress to retrieve the patterns of interannual anomalies in sea surface temperatures in a good agreement with independent NASA Pathfinder observations. Various upwelling indices are also calculated in the model to study specific warm or cold coastal events whose circulation schemes are detailed from a Lagrangian interpretation of the model time‐varying three‐dimensional velocity field. Our study emphasizes the connections established between the Benguela upwelling and the large‐scale circulation in relation with, for instance, the Agulhas Current retroflection and associated ring shedding.
Estimating the mechanical effects of riparian vegetation on stream bank stability using a fiber bundle model
Authors: Pollen Natasha , Simon Andrew
Published: July 2005

Recent research has suggested that the roots of riparian vegetation dramatically increase the geomechanical stability (i.e., factor of safety) of stream banks. Past research has used a perpendicular root reinforcement model that assumes that all of the tensile strength of the roots is mobilized instantaneously at the moment of bank failure. In reality, as a soil‐root matrix shears, the roots contained within the soil have different tensile strengths and thus break progressively, with an associated redistribution of stress as each root breaks. This mode of progressive failure is well described by fiber bundle models in material science. In this paper, we apply a fiber bundle approach to tensile strength data collected from 12 riparian species and compare the root reinforcement estimates against direct shear tests with root‐permeated and non‐root‐permeated samples. The results were then input to a stream bank stability model to assess the impact of the differences between the root models on stream bank factor of safety values. The new fiber bundle model, RipRoot, provided more accurate estimates of root reinforcement through its inclusion of progressive root breaking during mass failure of a stream bank. In cases where bank driving forces were great enough to break all of the roots, the perpendicular root model overestimated root reinforcement by up to 50%, with overestimation increasing an order of magnitude in model runs where stream bank driving forces did not exceed root strength. For the highest bank modeled (3 m) the difference in factor of safety values between runs with the two models varied from 0.13 to 2.39 depending on the riparian species considered. Thus recent work has almost certainly overestimated the effect of vegetation roots on mass stability of stream banks.
Assessing electron heat flux dropouts as signatures of magnetic field line disconnection from the Sun
Authors: Pagel C. , Crooker N. U. , Larson D. E.
Published: July 2005

Suprathermal electrons focused along magnetic field lines, called the strahl, carry heat flux away from the Sun. Various factors can cause heat flux dropouts (HFDs), including times when the strahl almost vanishes. HFDs are a necessary but insufficient condition for detecting magnetic flux disconnected from the Sun. To quantitatively assess the fraction of HFDs which might be due to disconnected fields, we use four years of suprathermal electron data from the Wind spacecraft to perform a comprehensive survey of heat flux dropouts with durations greater than an hour. Eliminating periods within interplanetary coronal mass ejections or containing counterstreaming electrons, we find that only ∼10% of HFDs have signatures consistent with disconnected flux.
Interplanetary shocks unconnected with earthbound coronal mass ejections
Authors: Howard T. A. , Tappin S. J.
Published: July 2005

An associated study by Howard and Tappin (2005) identified 7 Earthbound forward shocks (of which 3 were geoeffective) which were not connected with any detectable coronal mass ejection activity along the Sun‐Earth line. This largely unexplored result lends evidence to the fact that some large interplanetary transients are not detected by coronagraphs. This letter explores two possibilities for the formation of the interplanetary foreward shock, namely Corotating Interaction Regions (CIR) or Erupting Magnetic Structures (EMS). Data from EPAM, SWEPAM and MAG on board ACE provided details of the interplanetary shock and associated energetic ions along the Sun‐Earth line, while evidence of magnetic field reorientation at the Sun was investigated using EIT on board SOHO, the GOES network and ground‐based Hα and radio telescopes. No evidence was found to associate 6 of the shocks with CIRs, although we were uncertain about one event, and in each case evidence of chromospheric activity at the Sun was detected between the estimated onset time of the transient and the arrival of the shock at ACE. The nature of this surface activity included X‐Ray (≥C5.0) and Hα flares, associated Type III and Type II radio bursts and disappearing filaments. These results lead to the proposal that EMS are the likely source of some interplanetary transients.
Antitumour activity of fatty acid maltotriose esters obtained by enzymatic synthesis
Authors: Ferrer Manuel , Perez Gabriela , Plou Francisco J. , Castell José V. , Ballesteros Antonio
Published: July 2005

The antitumour properties of two fatty acid esters of maltotriose, 6″‐O‐dodecanoylmaltotriose and 6″‐O‐palmitoylmaltotriose, in which the 6‐OH at the non‐reducing end of the maltotriose has been regioselectively acylated, were studied. Both compounds were synthesized by transesterification of vinyl laurate or vinyl palmitate with maltotriose, in the presence of immobilized lipase from Thermomyces lanuginosus. A mixture of 2‐methylbutan‐2‐ol and DMSO (80:20, v/v) was the reaction medium. Their cytotoxic activities against two human cancer cell lines, Hep‐G2 and HeLa, were studied. 6″‐O‐palmitoylmaltotriose showed IC50 values of 2.3 μM (1.7 μg/ml) for Hep‐G2 and 3.6 μM (2.7 μg/ml) for HeLa cells, whereas 6″‐O‐dodecanoylmaltotriose displayed a lower inhibitory effect. 6″‐O‐palmitoylmaltotriose showed a marginal cytotoxicity to rat hepatocytes, confirming its potential as a new antitumour agent.
Use of plant‐derived protein hydrolysates for enhancing growth ofBombyx mori(silkworm) insect cells in suspension culture
Authors: Kwon Mi Sun , Dojima Takashi , Park Enoch Y.
Published: July 2005

The successful suspension culture of theBombyx mori(silkworm) cell lines Bm5 and BmN4 without FBS (fetal‐bovine serum) was first realized in Sf‐900 II SFM (serum‐free medium) (Gibco BRL, Rockville, MD, U.S.A.) supplemented with a plant‐derived protein hydrolysate. The addition of 0.5% HyPep 1510 (Difco Co., Detroit, MI, U.S.A.) and 10 mM glutamine to Sf‐900 II SFM at 4 days of culture was found effective in increasing the cell concentration to 8.5×106cells/ml. The replacement of medium with Sf‐900 II SFM supplemented with 0.5% HyPep 1510 at 6 days of culture increased the cell concentration by 1.1×107cells/ml. When Sf‐900 II SFM was supplemented with 0.5% Hypep 1510, 16 days, which was half of the conventional adaptation time, was sufficient for theB. moricell line to adapt to SFM and shear stress while maintaining a stable viability. The β‐galactosidase activity in Sf‐900 II SFM supplemented with 0.5% Hypep 1510 was 4.9×103units/ml, which was 2‐fold higher than that of the FBS‐supplemented medium. By SDS/PAGE, only the band corresponding to β‐galactosidase was detected in the sample from the media supplemented with plant‐derived protein hydrolysates, while thick bands corresponding to proteins having lower molecular masses than β‐galactosidase were detected in samples from the FBS‐supplemented media. These results suggest that plant‐derived protein hydrolysates are promising FBS substitutes for enhancing the growth ofB. moricells and facilitating the purification of recombinant proteins produced by baculovirus infection.
Application of a radial‐flow bioreactor in the production of β1,3‐N‐acetylglucosaminyltransferase‐2 fused with GFPuv using stably transformed insect cell lines
Authors: Kwon Mi Sun , Kato Tatsuya , Dojima Takashi , Park Enoch Y.
Published: July 2005

An RFB (radial‐flow bioreactor) with a reactor volume of 5 ml was applied to produce human β3GnT (β1,3‐N‐acetylglucosaminyltransferase) using two stably transformed insect cell lines. When air was supplied to the RFB, cell growth stopped at 4 days of culture and β3GnT was not detected. However, with a supply of pure oxygen, the cell concentration, assumed from glucose consumption, increased by 1.3×107 cells/ml. Insect cells attached to poly(vinyl alcohol) matrixes packed in the RFB and grew confluently; 5.6 m‐units/ml β3GnT was produced under the conditions of pure oxygen supply and addition of glucose and glutamine. This RFB was first applied in β3GnT production using stably transformed insect cells. The amount of β3GnT production in only a 5 ml‐scale RFB was comparable with that of a 100 ml shaking flask culture.
Immunomodulatory and antitumour effects of an exopolysaccharide fraction from cultivated Cordyceps sinensis (Chinese caterpillar fungus) on tumour‐bearing mice
Authors: Zhang Weiyun , Yang Jinyu , Chen Jiaping , Hou Yayi , Han Xiaodong
Published: July 2005

Cordyceps sinensis (Chinese caterpillar fungus) is a fungus parasitic on the larvae of Lepidoptera and has been considered to be a precious tonic food and herbal medicine since ancient times in China. Recently, some fungal strains have been isolated from the fruiting bodies of wild C. sinensis, and some of them have been reported to show the same properties as the natural product. In the present study, an EPSF (exopolysaccharide fraction) was prepared from cultivated C. sinensis and its effects on B16 melanoma‐bearing mice were investigated. Three doses of EPSF were intraperitoneally administered every 2 days after the day of tumour‐cell injection. The experiment was terminated on day 28. Phagocytosis of peritoneal macrophages and proliferation of spleen and thymus lymphocytes were assayed. The tumour metastatic foci on the lung and liver surface were checked. The expression of oncoprotein Bcl‐2 in livers and lungs was assayed by a immunohistochemical method. The results showed that EPSF significantly enhanced the Neutral Red uptake capacity of peritoneal macrophages (60 mg/kg, P<0.01; 120 mg/kg, P<0.001) and spleen lymphocyte proliferation (60 mg/kg, P<0.05; 120 mg/kg, P<0.001) in B16‐bearing mouse. The metastasis of B16 melanoma cells to lungs (120 mg/kg) and livers (30, 60 and 120 mg/kg) was significantly inhibited by EPSF. Moreover, EPSF decreased the levels of Bcl‐2 in the lungs (120 mg/kg) and livers (30, 60 and 120 mg/kg). These results suggest that EPSF has immunomodulatory function and antitumour activity.
Increasing the culture efficiency of hybridoma cells by the use of integrated metabolic control of glucose and glutamine at low levels
Authors: Li Ling , Mi Li , Feng Qiang , Liu Rong , Tang Hao , Xie Li , Yu Xiaoling , Chen Zhinan
Published: July 2005

The metabolism of HAb18 hybridoma cells was shifted to decrease metabolite accumulation and to improve culture efficiency by integrated metabolic control of glucose and glutamine at low levels. When glucose and glutamine levels were decreased to 0.5 and 0.3 mM respectively, lactate and ammonia production were reduced by 62.6 and 74% respectively, glucose‐to‐cell yield was increased from 0.23×109 to 0.66×109 cells·mmol−1, and glutamine‐to‐cell yield from 0.18×109 to 1.95×109 cells·mmol−1. Compared with high‐level glucose and glutamine fed‐batch cultures, low‐level glucose and glutamine led to higher cell density (1.0×107 versus 0.3×107 cells·ml−1), longer culture span (14 as opposed to 8 days) and higher antibody yield (250 as against 150 mg·l−1). These results indicate that hybridoma culture efficiency would be increased by the integrated control of glucose and glutamine at 0.5 and 0.3 mM respectively. In contrast with previously reported glucose‐and/or‐glutamine‐level‐controlled fed‐batch cultures, we demonstrated an efficient strategy of nutrient level selection and amino acid feeding. More importantly, our accurately and well‐distributed Equable Feeding Control System opens a new avenue for reducing metabolites to low levels by controlling nutrients at low levels.
Molecular simulation of dendrimers and their mixtures under shear: Comparison of isothermal-isobaric (NpT) and isothermal-isochoric (NVT) ensemble systems
Authors: Bosko Jaroslaw T. , Todd B. D. , Sadus Richard J.
Published: July 2005

Flow properties of dendrimers are studied with the aid of nonequilibrium molecular dynamics techniques. Simulations are performed in the NpT ensemble using the NpT-SLLOD algorithm [P. J. Davis and D. J. Evans, J. Chem. Phys. 100, 541 (1994)] and are compared to the results from simulations performed in the NVT ensemble reported earlier [J. T. Bosko, B. D. Todd, and R. J. Sadus, Chem. Phys. 121, 12050 (2004)]. Shear thickening observed at high strain rates vanishes in systems kept under constant pressure. Also the exponents in the power-law dependencies of the viscosity and the normal stress coefficients change. The variations are significant only at high strain rates and do not affect largely microscopic properties such as shape, alignment, or rotation of molecules. The NpT-SLLOD algorithm has been applied to study various systems including dendrimers in solution and their blends with linear chain molecules of the same molecular mass, and some results for these systems are presented.
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and 1s22s23l, l=s,p,d, excited states of boron isoelectronic series from explicitly correlated wave functions
Authors: Gálvez F. J. , Buendía E. , Sarsa A.
Published: July 2005

For some members of the boron isoelectronic series and starting from explicitly correlated wave functions, six low-lying excited states have been studied. Three of them arise from the 1s22p3 configuration, and the other three from the 1s22s23l, l=s,p,d, configurations. This work follows a previous one on both the 1s22s22p-P2 ground state and the four excited states coming from the 1s22s2p2 configuration. Energies, one- and two-body densities in position space and some other two-body properties in position and momentum spaces have been obtained. A systematic analysis of the energetic ordering of the states as a function of the total orbital angular momentum and spin is performed in terms of the electron-nucleus and electron-electron potential energies and the role of the angular correlation is discussed. All calculations have been carried out by using the Monte Carlo algorithm.
Photodissociation of the water dimer: Three-dimensional quantum dynamics studies on diabatic potential-energy surfaces
Authors: Valenzano Loredana , van Hemert Marc C. , Kroes Geert-Jan
Published: July 2005

The results are presented of three-dimensional model studies of the photodissociation of the water dimer following excitation in the first absorption band. Diabatic potential-energy surfaces are used to investigate the photodissociation following excitation of the hydrogen bond donor molecule and of the hydrogen bond acceptor molecule. In both cases, the degrees of freedom considered are the two OH-stretch modes of the molecule being excited, and the dimer stretch vibration. The diabatic potentials are based on adiabatic potential surfaces computed with the multireference configuration-interaction method, and the dynamics of dissociation was studied using the time-dependent wave-packet method. The dynamics calculations yield a donor spectrum extending over roughly the same range of frequencies as the spectrum of the water monomer computed at the same level of theory. The acceptor spectrum has the same width as the monomer spectrum, but is shifted to the blue by 0.4–0.5eV. The dimer spectrum obtained by averaging the donor and the acceptor spectrum is broader than the monomer spectrum, with the center of the dimer first absorption band shifted to the blue by about 0.2eV relative to the monomer band. Our reduced dimensionality calculations do not find the red tail predicted for the dimer first absorption band by Harvey et al. [J. Chem. Phys. 109, 8747 (1998)]. This conclusion also holds if preexcitation of the dimer stretch vibration with one or two quanta is considered.
Construction of Parseval wavelets from redundant filter systems
Authors: Baggett L. W. , Jorgensen P. E. T. , Merrill K. D. , Packer J. A.
Published: July 2005

We consider wavelets in L2(Rd) which have generalized multiresolutions. This means that the initial resolution subspace V0 in L2(Rd) is not singly generated. As a result, the representation of the integer lattice Zd restricted to V0 has a nontrivial multiplicity function. We show how the corresponding analysis and synthesis for these wavelets can be understood in terms of unitary-matrix-valued functions on a torus acting on a certain vector bundle. Specifically, we show how the wavelet functions on Rd can be constructed directly from the generalized wavelet filters.
Formation of two-dimensional electron gases in polytypic SiC heterostructures
Authors: Polyakov V. M. , Schwierz F.
Published: July 2005

The formation of two-dimensional electron gases (2DEGs) at polytypic (hexagonal/cubic) SiC heterojunctions (4H/3C SiC and 6H/3C SiC) is investigated by numerical self-consistent solutions of the Schrödinger and Poisson equations. The free-electron-density distributions and conduction-band profiles in the SiC heterostructures are calculated and compared to those occurring at AlGaN/GaN interfaces. Spontaneous and piezoelectric polarization effects in both SiC/SiC and AlGaN/GaN structures are taken into account. The combined effect of the polarization-induced bound charge and conduction-band offset between the hexagonal and cubic SiC polytypes results in the formation of 2DEGs with very high electron sheet concentration. 2DEG sheet densities about 20% larger than that in Al0.3Ga0.7N/GaN structures are calculated for 4H/3C SiC heterostructures. We also find that the 2DEG densities in the 4H/3C are much less sensitive to variations of the barrier layer thickness. The influence of the barrier doping layer on the 2DEG densities is also investigated.
Optical properties of ferroelectric nanocrystal-containing polymer BaTiO3∕polycarbonate films
Authors: Liu W. C. , Li A. D. , Tan J. , Mak C. L. , Wong K. H. , Wu D. , Ming Nai-Ben
Published: July 2005

BaTiO 3 (BT)-nanocrystal-doped polycarbonate polymer composite thin films (BT/PC) with different BT concentrations were prepared by spin-coating method. Ultrafine BT (∼40–50nm) nanocrystals with pure perovskite tetragonal phase were synthesized by hydrothermal method. The structure of BT nanocrystals and composite films were studied by means of x-ray diffraction and transmission scanning microscopy. The composite films were poled with a high electric field at a suitable temperature to yield a noncentrosymmetric arrangement and produce better electro-optic properties. The poling condition under external electric field was optimized through the dielectric properties of BT and PC polymer and the effective-field intensity theory. The electro-optic (EO) coefficients and transmittance of composite films with various BT concentrations were also evaluated. The average effective linear EO coefficient and figure of merit of 20-wt % BT-doped composite films were about 63.1 and 103.1pm∕V, respectively. BT/PC composite films show excellent electro-optic properties for application in integrated optoelectronics and optics.
A porous silicon diode as a source of low-energy free electrons at milli-Kelvin temperatures
Authors: Pilla S. , Naberhuis B. , Goodkind J.
Published: July 2005

We have developed a porous silicon (PS) diode that yields free-electron currents with energies <0.1eV below 77 K. The power dissipated during emission is low so that pulses of electrons can be produced below 100 mK without raising the temperature of the system. Free electrons were generated in liquid He4 and He3 as well. The device was developed as a source of electrons for a quantum computing system using electrons on the surface of a dielectric film. The results suggest that a Poole-Frenkel type of mechanism accounts for the observed electric-field-enhanced conduction but the electron emission mechanism is not well understood in the present models of PS.
Electrostrictive effect in lead-free relaxor K0.5Na0.5NbO3–SrTiO3 ceramic system
Authors: Bobnar V. , Malič B. , Holc J. , Kosec M. , Steinhausen R. , Beige H.
Published: July 2005

The elastic strain of lead-free relaxor K0.5Na0.5NbO3–SrTiO3 ceramic system, induced by applied electric fields with amplitudes up to 40kV∕cm, has been investigated. The strain response, being similarly low (order of 10−5) as in the classical lead magnesium niobate relaxor, is shown to be of solely electrostrictive origin, as a pure quadratic relation holds between induced strain and electric polarization. The strain dependence on the SrTiO3 content is presented and discussed. Furthermore, electrostrictive coefficients are shown to be constant over a broad temperature range and, similar to dielectric properties, independent of electric-field cycles, which suggests possible applications of this translucent, high-dielectric constant, and environmental-friendly ceramic system.
Fast growing double tearing modes in a tokamak plasma
Authors: Bierwage Andreas , Benkadda Sadruddin , Hamaguchi Satoshi , Wakatani Masahiro
Published: July 2005

Configurations with nearby multiple resonant surfaces have broad spectra of linearly unstable coupled tearing modes with dominant high poloidal mode numbers m. This was recently shown for the case of multiple q=1 resonances [Bierwage et al., Phys. Rev. Lett. 94 65001 (2005)]. In the present work, similar behavior is found for double tearing modes (DTM) on resonant surfaces with q⩾1. A detailed analysis of linear instability characteristics of DTMs with various mode numbers m is performed using numerical simulations. The mode structures and dispersion relations for linearly unstable modes are calculated. Comparisons between low- and higher-m modes are carried out, and the roles of the inter-resonance distance and of the magnetic Reynolds number SHp are investigated. High-m modes are found to be destabilized when the distance between the resonant surfaces is small. They dominate over low-m modes in a wide range of SHp, including regimes relevant for tokamak operation. These results may be readily applied to configurations with more than two resonant surfaces.
PbS quantum dot electroabsorption modulation across the extended communications band 1200–1700nm
Authors: Klem Ethan J. D. , Levina Larissa , Sargent Edward H.
Published: July 2005

We report electric field-induced modulation of absorption in PbS nanocrystal quantum dots across the spectral region 600–2000nm, encompassing the entire telecommunications band. The maxima in the electroabsorption spectra correspond with the positions of the first excitonic peak, confirming the predominance of excitonic broadening as the basis for the observed effect. We estimate the change in dipole moment to be on the order of 20 D in 7nm diameter PbS nanocrystals compared to previously-reported ∼100D in CdSe.
Well-defined excited states of self-assembled InAs∕InAlGaAs quantum dots on InP (001)
Authors: Kim Jin Soo , Lee Jin Hong , Hong Sung Ui , Kwack Ho-Sang , Choi Byung Seok , Oh Dae Kon
Published: July 2005

Self-assembled InAs∕InAlGaAs quantum dots (QDs) in an InAlGaAs matrix on InP (001) substrates were grown by the alternate growth method (AGQD), where an InAs layer with a thickness of 1 monolayer (ML) and an InAlGaAs layer with a thickness of 1 ML were alternately deposited. Cross-sectional transmission electron microscopy images indicated that the aspect ratio (height/width) for the AGQDs was ∼0.25, which was higher than ∼0.10 of conventionally grown InAs QDs. The photoluminescence (PL) peak position for the ground states of the AGQDs was 1.485μm with a linewidth broadening of 42meV at room temperature, while the PL linewidth for the conventionally grown QDs was 85meV. And the peaks for the excited-state transitions were also clearly observed from the excitation-power dependent PL. This is the first observation on the well-defined excited-state transitions from the InP-based InAs QDs, even though there were several reports on the features of the excited states.
Mechanism of nanoparticle agglomeration during the combustion synthesis
Authors: Altman Igor S. , Agranovski Igor E. , Choi Mansoo
Published: July 2005

The mechanism of agglomeration of nanoparticles generated during combustion synthesis is discussed. This is based on the analysis of the transmission electron microscope images of probes collected at different heights. Although direct temperature measurements were not available, the qualitative temperature dependence of the particle formation streamlines is taken into account. It is demonstrated that agglomeration of the MgO nanoparticles, which are formed during a Mg particle combustion, occurs as the result of bonding the mature nanoparticles by the supercritical clusters existing in the system. Accumulation of these supercritical clusters in the flame has been revealed and their nature has been explained in our recent paper [I.S. Altman, I.E. Agranovski, and M. Choi, Phys. Rev E 70, 062603 (2004)]. Also, some inspection of the previously published experimental data on the nanoparticle generation shows that the similar supercritical clusters may exist in another flame reactor generating titania nanopaprticles. If this is the case, the cluster-based process of nanoparticle bonding we suggest can be considered to be general.