bluuebunny/crossref_metadata_2025_split huggingface dataset:
Adsorption of catechol and comparative solutes on hydroxyapatite
Authors: Chirdon William M. , O'Brien William J. , Robertson Richard E. 
Published: July 2003

AbstractContemporary medical and dental adhesives often have difficulty sticking to wet surfaces or weaken with long‐term exposure to water. Substantial research has been dedicated to finding a means of achieving adhesion in an aqueous environment. A study evaluates the adsorption of catechol relative to other chemical groups as means of gauging how effective they may be as adsorptive groups in adhesives. Contact angle and surface‐tension measurements of solutions of catechols and other chemical groups were used to determine their works of adhesion. Adsorption isotherms were also constructed to ascertain Langmuir constants. Solutes containing catechol groups were compared to solutes containing other polar groups to see how well catechol adsorbs to hydroxyapatite, the mineral component of bones and teeth, relative to other chemical groups found in adhesives. The results of this study show that catechol and molecules containing catechol groups have higher rates and energies of adsorption to hydroxyapatite than do groups such as alcohols, amines, and carboxylic acids. © 2003 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 66B: 532–538, 2003
In vivo histological response to anodized and anodized/hydrothermally treated titanium implants
Authors: Son Won‐woo , Zhu Xiaolong , Shin Hong‐in , Ong Joo L. , Kim Kyo‐han 
Published: July 2003

AbstractIn the study, characterization of the anodized titanium surface was performed. In addition, histological evaluation and interfacial strength at the bone–implant interface of the characterized surfaces were then evaluated with the use of a rabbit model at 6 and 12 weeks after implantation. Surface treatments consisted of either anodization or anodization followed by hydrothermal treatments. Nontreated titanium surfaces were used as controls in this study. Using scanning‐electron microscopy, porous oxide layers were observed on surfaces of anodized titanium implants, whereas porous oxide layers and HA needles were observed on anodized titanium implants following hydrothermal treatments. X‐ray diffraction analysis showed the oxide layers were consisted mainly of anatase and a little of rutile. By the hydrothermal treatment on the anodizing surface, HA peaks, as well as the peaks of anatase and trace amounts of rutile peaks were observed. In EPMA analysis, the Ca/P ratio for the anodic oxide was 1.54 for anodized surfaces, whereas the Ca/P ratios for HA needles and the anodic oxide were 1.64 and 0.57, respectively, for anodized surfaces following hydrothermal treatments. Although no significant difference was observed for the percent bone contact on all implants evaluated in the in vivo study, the removal torque strength was significantly higher for anodized implants (48.02 ± 5.92 N/cm) than the untreated implants (controls) (27.83 ± 1.78 N/cm) at 6 weeks after implantation. As such, it was concluded that the surface anodized implants resulted in a high interfacial strength at an early implantation period as compared to the nontreated titanium implants. © 2003 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 66B: 520–525, 2003
Use of isothermal heat‐conduction microcalorimetry (IHCMC) for the evaluation of synthetic biomaterials
Authors: Lewis Gladius , (Dan) Daniels A. U. 
Published: July 2003

AbstractIsothermal heat‐conduction microcalorimetry (IHCMC) allows measurement of extremely small rates of heat flow—on the order of 0.1 microwatt. This provides, for example, the ability to directly observe—and quantitate in a few days—rates of degradation as low as 1% per year at body temperature, in solid material samples of a few grams. Also, one method of IHCMC data analysis allows direct determination of the reaction‐rate constant at the temperature of interest, thereby avoiding possible errors due to rate mechanism changes with temperature, an issue that needs to be considered when the Arrhenius method is used. IHCMC can also be used to measure transient phenomena, such as heat of adsorption, and initial metabolic responses of cellular entities to biomaterials. The purposes of this review article are to (a) explain the basic principles, attractive features, limitations, and methods of IHCMC; (b) describe biomaterials applications to date—including studies of the stability of ultra‐high‐molecular‐weight polyethylene and implant‐grade calcium sulfate, setting reactions of dental adhesives, and macrophage response to biomaterial particles; (c) provide a discussion of issues and concerns that should be addressed in order to maximize the utility of IHCMC in biomaterials studies; and (d) suggest a number of possible future biomaterials applications for this technique. © 2003 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 66B: 487–501, 2003
The preparation of monodisperse biodegradable polyester nanoparticles with a controlled size
Authors: Zweers Miechel L.T. , Grijpma Dirk W. , Engbers Gerard H.M. , Feijen Jan 
Published: July 2003

AbstractIn local drug delivery, nanoparticles based on biodegradable polymers can function as vehicles with controlled drug‐release properties. To achieve a well‐controlled drug‐release profile, control over the particle size is of great importance. Therefore, biodegradable polyester nanoparticles were prepared by the salting‐out method. Process variables were varied to study the effect on the particle size. The monodisperse particles obtained were between 100 and 400 nm in size and spherical in shape. It was found that the particle size could be adjusted by varying the preparation conditions upon which the polymer concentration had the most pronounced effect. © 2003 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 66B: 559–566, 2003
Synthesis of 4‐[18F]fluoroiodobenzene and its application in sonogashira cross‐coupling reactions
Authors: Wüst Frank R. , Kniess Torsten 
Published: July 2003

AbstractThe first application of a Sonogashira cross‐coupling reaction in 18F chemistry has been developed. The reaction was exemplified by the cross‐coupling of terminal alkynes (ethynylcyclopentyl carbinol 6, 17α‐ethynyl‐3,17β‐estradiol 7 and 17α‐ethynyl‐3‐methoxy‐3,17β‐estradiol 8) with 4‐[18F]fluoroiodobenzene. 4,4′‐Diiododiaryliodonium salts were used as precursors for the synthesis of 4‐[18F]fluoroiodobenzene, enabling the convenient access to 4‐[18F]fluoroiodobenzene in 13–70% yield using conventional heating or microwave activation. The Sonogashira cross‐coupling of 4‐[18F]fluoroiodobenzene with terminal alkynes gave the corresponding 4‐[18F]fluorophenylethynyl‐substituted compounds [18F]‐9, [18F]‐10 and [18F]‐13 in yields up to 88% within 20 min of starting from 4‐[18F]fluoroiodobenzene. Copyright © 2003 John Wiley & Sons, Ltd.
125I‐Labeled 2‐O‐ and 3‐O‐m‐iodobenzyl, and 6‐O‐m‐iodophenyl derivatives of L‐ascorbic acid: synthesis and preliminary tissue distribution
Authors: Yamamoto Fumihiko , Kuwano Eri , Kaneshiro Tetsuo , Sasaki Shigeki , Maeda Minoru 
Published: July 2003

AbstractThree 125I‐labeled 2‐O‐ and 3‐O‐m‐iodobenzyl, and 6‐O‐m‐iodophenyl derivatives of L‐ascorbic acid were prepared by melt exchange procedures in isolated radiochemical yields of 12–60% after HPLC purification. Biodistribution studies in tumor‐bearing mice showed very different in vivo tissue uptake properties from previous results obtained with 14C‐labeled ascorbic acid and 6‐deoxy‐6‐[18F]fluoro‐L‐ascorbic acid. None of these seems to be suitable radioiodinated analogs of L‐ascorbic acid for imaging study of its in vivo biochemistry. Copyright © 2003 John Wiley & Sons, Ltd.
Preparation and biological evaluation of 99mTc‐stannous fluoride colloid‐labelled‐leucocytes in rats 99mTc‐stannous fluoride‐labelled‐leucocytes in rats
Authors: Tsopelas C. , Smith E. , Drew P.A. , Bartholomeusz F.D.L. 
Published: July 2003

AbstractHigh splenic activity is always visible in 99mTc‐stannous fluoride (SnF2)‐labelled‐leucocytes scans. In an attempt to reduce this activity, this study investigated the effect of pre‐injected SnF2 colloid on the distribution of 99mTc‐SnF2 colloid, 99mTc‐SnF2‐labelled‐leucocytes, and opsonized 99mTc‐SnF2 colloid in rats. The radiopharmaceuticals 99mTc‐SnF2 colloid and 99mTc‐SnF2‐leucocytes were each found to exhibit identical biodistributions in separate experiments. SnF2 colloid pre‐injection (26 μg) resulted in reduced splenic uptake of 99mTc‐SnF2 colloid (38%) and 99mTc‐SnF2‐labelled‐leucocytes (30%), but not for opsonized 99mTc‐SnF2 colloid. This indicates that the level of opsonization of radiocolloid is rate limiting rather than the phagocytic capacity of liver and spleen macrophages. There is a low level of 99mTc‐SnF2‐labelled‐leucocytes dominated by unopsonized radiocolloid in the ex vivo whole blood dose. Following administration of this dose, free radiocolloid is present in vivo that predominantly localizes in the liver and spleen. This uptake can be challenged with non‐radioactive stannous fluoride colloid pre‐injection, where splenic activity can be significantly reduced by up to 52%. Copyright © 2003 John Wiley & Sons, Ltd.
Redefining the climate zones of Turkey using cluster analysis
Authors: Unal Yurdanur , Kindap Tayfun , Karaca Mehmet 
Published: July 2003

AbstractClimate zones of Turkey are redefined by using the mathematical methodology of cluster analysis. Data from 113 climate stations for temperatures (mean, maximum and minimum) and total precipitation from 1951 to 1998 are used after standardizing with zero mean and unit variance, to confirm that all variables are weighted equally in the cluster analysis. Hierarchical cluster analysis is chosen to perform the regionalization. Five different techniques were applied initially to decide the most suitable method for the region. Stability of the clusters is also tested. It is decided that Ward's method is the most likely to yield acceptable results in this particular case, as is often the case in climatological research. Seven different climate zones are found, as in conventional climate zones, but with considerable differences at the boundaries. Copyright © 2003 Royal Meteorological Society
Comparison of techniques for detection of discontinuities in temperature series
Authors: Ducré‐Robitaille Jean‐François , Vincent Lucie A. , Boulet Gilles 
Published: July 2003

AbstractSeveral techniques for the detection of discontinuities in temperature series are evaluated. Eight homogenization techniques were compared using simulated datasets reproducing a vast range of possible situations. The simulated data represent homogeneous series and series having one or more steps. Although the majority of the techniques considered in this study perform very well, two methods seem to work slightly better than the others: the standard normal homogeneity test without trend, and the multiple linear regression technique. Both methods are distinctive because of their sensitivity concerning homogeneous series and their ability to detect one or several steps properly within an inhomogeneous series. Copyright © 2003 Environment Canada. Published by John Wiley & Sons, Ltd.
Frequency of Bay of Bengal cyclonic storms and depressions crossing different coastal zones
Authors: Alam Md. Mahbub , Hossain Md. Arif , Shafee Sultana 
Published: July 2003

AbstractAll the storms and depressions that formed in the Bay of Bengal during 1974–99 have been analysed. The number of occurrences in July is not in harmony with that of other months of the monsoon. Regions stricken are taken into account on a monthly, seasonal and annual basis. The Indian coast faces almost an equal number of storms and depressions that are formed from June to November. The most vulnerable months for storms are May, October and November for Bangladesh; May for Myanmar; June, August and September for Kolkata–Vishakhapatnam in India and October and November for Vishakhapatnam–Tamilnadu in India. Most of the monsoon depressions cross the Kolkata–Vishakhapatnam coast of India. The frequency of formation has been observed to decrease during the period of analysis. It is also observed that the frequency distribution of the Bay of Bengal storms has two peaks: one in the month of May and the other in the month of November. Copyright © 2003 Royal Meteorological Society
The influence of natural conditions on the spatial variation of climate in Lapland, northern Finland
Authors: Vajda Andrea , Venäläinen Ari 
Published: July 2003

AbstractAt high latitudes in Lapland, near the climatological timberline, forestry and other environmental research require detailed information about the spatial variation of climate. In this study, the influence of local geographical factors on the climate in northern Finland (Lapland), as well as the applicability of the kriging interpolation method in the case of detailed spatial resolution, were examined. The spatial analysis of mean, maximum, minimum temperatures, length of the frost‐free season, degree‐days and daily range was made using a 1 km × 1 km resolution. The time period used was 1971–2000. We studied whether taking account of external forcing, such as lake coverage and altitude, would improve the accuracy of spatial interpolation of climatological parameters. The geographical factors of coordinates, elevation, lakes and sea influence on the regional features of the climate were examined. According to the results of this study, only geographical position and local relief have a significant influence on regional climate in Lapland. The effect of lakes and sea seems to be secondary. Copyright © 2003 Royal Meteorological Society
Variability of extreme temperature events in south–central Europe during the 20th century and its relationship with large‐scale circulation
Authors: Domonkos Peter , Kyselý Jan , Piotrowicz Katarzyna , Petrovic Predrag , Likso Tanja 
Published: July 2003

AbstractThe variability of winter extreme low‐temperature events and summer extreme high‐temperature events was investigated using daily temperature series (1901–98) from 11 sites in central and southern Europe. An extreme temperature event (EXTE) is defined by various threshold values of daily temperature or daily temperature anomaly. Systematic changes in the frequencies of EXTEs are investigated by the Mann–Kendall test and a method based on the Wilcoxon test. The catalogue of macrocirculation types over central Europe (the Hess–Brezowsky classification) is applied to investigate the connections between EXTEs and large‐scale circulation. Circulation classes (HBC) are defined, and mostly spatial averages of EXTEs are examined.There were large long‐term fluctuations in the frequencies of both winter extreme cold events (EXCEs) and summer extreme warm events (EXWEs) during the 20th century. The systematic changes referring to the entire period indicate a slight warming tendency, but only a few of the changes, mostly in the northernmost sites, are statistically significant. Strong connections are present between the frequencies of EXTEs and the large‐scale circulation on various time scales, particularly for EXCEs. The spatial differences of EXTE fluctuations and EXTE–HBC connections are small within the study area. Northerlies and easterlies, as well as meridional and anticyclonic situations, are favourable for EXCEs, whereas southerlies and persistent anticyclonic situations are favourable for EXWE occurrences. In the latest decades, a decline in the frequency of EXCEs and a sharp increase in the frequency of EXWEs happened, and the residence times of the circulation patterns over central Europe became longer both in winter and summer. Copyright © 2003 Royal Meteorological Society
An automated enantioselective isolation system for the study of estrogenic potencies: Study of the estrogenic activity of α‐hexachlorocyclohexane
Authors: Hashimoto Shinya , Yoshimoto Takeshi , Nakao Masumi , Omura Hiroshi , Yamashita Nobuyoshi , Kannan Kurunthachalam , Giesy John P. 
Published: July 2003

AbstractHerein we describe an automated enantioselective isolation system that uses a gas chromatograph‐flame ionization detector (FID)‐preparative fraction collector to separate the enantiomers of chiral compounds. In this system, a switching device was coupled with six glass tubes containing an organic solvent for the separate collection of six compounds, thus eliminating the need for a manual collection procedure after separation by gas chromatography. To evaluate the usefulness of this system, we applied it to the separation and collection of the enantiomers of α‐hexachlorocyclohexane (α‐HCH), and we measured the estrogenic potency of each enantiomer by means of an MVLN cell (Michigan Cancer Foundation‐7 (MCF‐7) cell stably transfected with a pVit‐tk‐LUC reporter plasmid) bioassay and an estrogen receptor binding assay. The variability in the retention time of each enantiomer (relative standard deviation, n = 16) was typically < 0.05%. The recoveries of the dextrorotatory (+) and levorotatory (–) enantiomers of α‐HCH were about 68.8% and 73.4%, respectively. The overall quantity of each enantiomer of α‐HCH collected was about 300 μg. Both enantiomers of α‐HCH showed similar estrogenic activity. On the basis of the results obtained for α‐HCH, we concluded that this analytical method is suitable for the determination of the estrogenic activity of other chiral compounds. Such determinations are essential because enantiomers differ considerably in how they accumulate in organisms and decompose in the environment.
Separation and determination of small amounts of sulfur in technical thiophanate‐methyl by reversed‐phase high‐performance liquid chromatography
Authors: Rao R. Nageswara , Venkateswarlu N. , Rao B. Vittal , Raju P. V. K. , Krishnaiah A. 
Published: July 2003

AbstractA simple and rapid reversed phase high‐performance liquid chromatographic method for separation and determination of elemental sulfur in technical thiophanate‐methyl using a reversed‐phase C18 column and methanol‐water‐tetrahydrofuran (90 : 8 : 2 v/v/v) as eluent with UV detection at 254 nm has been developed and validated with respect to accuracy, precision, specificity, linearity range, and limits of detection and quantification. The method was found to be suitable not only for detection but also determination of elemental sulfur at levels of 5×10–9 g.
Polyethylene powder microcolumn for protein separation prior to HPLC plasma analysis. Application to the determination of copper and zinc
Authors: Mendonça Jean Karlo Acosta , Cícero do Nascimento Paulo , Bohrer Denise 
Published: July 2003

AbstractThree different types of polyethylene powder (PE) were investigated with regard to their ability to adsorb proteins, with the goal of accomplishing plasma deproteinization for further HPLC analysis. Best results were obtained with ultrahigh molecular mass polyethylene The proteins retained by the PE powder were washed out of the column with methanol followed by water. A chromatographic system with the PE column as pre‐column was set up for the determination of copper and zinc in plasma. The plasma sample was injected into the chromatograph, and, on passage through the pre‐column, the proteins were adsorbed onto the PE. While a protein‐free eluate was being sent to the analytical column, by switching the pump channels the pre‐column was being flushed with methanol and water to elute the adsorbed proteins. After washing, the pre‐column was conditioned with the eluent to receive the next sample. Copper and zinc determination was performed by HPLC with photometric detection after post‐column derivatization with 4‐(2‐pyridylazo)resorcinol (PAR). The results, compared with those from flame atomic absorption spectrometry, showed that zinc can be determined by direct injection of the sample, but copper only after dilution. As the copper recovery from undiluted samples was about 65%, it was probably retained together with the proteins. However, on previous dilution of the sample with the eluent (acidic solution of lactic acid) the copper recovery reached 100%. The proposed method is suitable for the HPLC determination of copper and zinc in plasma samples without further sample treatment, in about 30 min.
Separation and microcolumn preconcentration of traces of rare earth elements on nanoscale TiO2 and their determination in geological samples by ICP‐AES
Authors: Hang Yiping , Qin Yongchao , Shen Jing 
Published: July 2003

AbstractA simple, rapid microcolumn preconcentration and separation technique is described for the determination of the trace rare earth elements Sm, Tm, Ho, and Nd in geological samples by Inductively Coupled Plasma Atomic Emission Spectrometry (ICP‐AES). The technique was based on adsorption of analytes on Nanometer‐Size Titanium Dioxide (NSTD) packed in a microcolumn and separation from the matrix at pH = 7.0. Quantitative adsorption of more than 94% of analytes was obtained in this work. The dynamic adsorption capacities of NSTD were found to be 14.59, 12.86, 14.38, and 15.58 mg g–1 for Tm, Sm, Ho, and Nd, respectively. The analytes were recovered quantitatively from NSTD with 2.0 mol L–1 HCl. The analytical procedure was optimized in terms of sample acidity, elution, flow rate of sampling, and sample volume. At a flow rate of 1.0 mL min–1, the detection limits (3σ) of the technique for Tm, Sm, Ho, and Nd with an enrichment factor of 50 were 0.06, 0.18, 0.08, and 0.1 ng mL–1, and the RSD were 1.8%, 4.7%, 2.0%, and 1.6%, respectively.
Analysis of aristolochic acids in herbal medicines by LC/UV and LC/MS
Authors: Lee Ming‐Chung , Tsao Chi‐Hsiang , Iou Song‐Chou , Chuang Wu‐Chang , Sheu Shuenn‐Jyi 
Published: July 2003

AbstractTwo high‐performance liquid chromatographic methods, one combined with a photodiode array detector (LC/UV) and another with mass spectrometry (LC/MS), were developed for the analysis of aristolochic acid I and II in herbal medicines. The LC/UV method was carried out using a Cosmosil 5C18‐MS column with a gradient solvent system composed of phosphate buffer‐acetonitrile and a UV detector (390 nm). The LC/MS method was performed using an acetate buffer‐acetonitrile solvent system and positive‐ion electrospray ionization MS. The characteristic fragment ions for aristolochic acid I were selected at m/z 359, m/z 324, m/z 298, and m/z 296, and for aristolochic acid II at m/z 329, m/z 294, and m/z 268. In order to attain better resolution, solid phase extraction was used to prepare the test solution in this study.
A new selective SPME fiber for some n‐alkanes and its use for headspace sampling of aqueous samples
Authors: Farajzadeh Mir Ali , Hatami Mehdi 
Published: July 2003

AbstractThis contribution presents a new porous solid phase microextraction (SPME) fiber based on cellulose acetate and polyvinyl chloride (PVC) coated on a metallic base. The proposed fiber is selective for n‐alkanes higher than C10, especially for C12–C15. PVC acts as a binder and surface modifier of the fiber. Fiber preparation can be completed in less than 15 min. High capacity, chemical, thermal, and mechanical durability, low cost, and no occurrence of additional peaks in chromatograms are further advantages of the proposed fiber. The relative standard deviations obtained from a single fiber are less than 9% for all analytes. The fiber‐to‐fiber reproducibility is better than 18%. After optimizing experimental conditions such as fiber composition, extraction time, desorption temperature, solution volume, salting out effect, etc. the fiber can be used for sampling from the headspace of aqueous solutions containing n‐alkanes (C10–C20) in the μg/L concentration range. Detection limits of 50–150 μg/L are obtained on use of capillary gas chromatographic separation and flame ionization detection. The microextraction procedure is rapid and equilibration takes less than 20 min.