bluuebunny/crossref_metadata_2025_split huggingface dataset:
Flow field‐flow fractionation with chemiluminescence detection for flow‐assisted, multianalyte assays in heterogeneous phase
Authors: Reschiglian Pierluigi , Zattoni Andrea , Melucci Dora , Roda Barbara , Guardigli Massimo , Roda Aldo 
Published: October 2003

AbstractOn‐line, continuous chemiluminescence detection has been recently applied to gravitational field‐flow fractionation as a new method suitable for flow‐assisted assays based on the separation between the analyte in solution and the analyte bound to micrometer‐sized particles. In this work, flow field‐flow fractionation coupled with off‐line chemiluminescence detection is exploited for the development of flow‐assisted, multianalyte assays. Micrometer‐sized, polystyrene beads coated with enzymes suitable for chemiluminescence detection, such as horseradish peroxidase and alkaline phosphatase, are used as model samples. The high size‐based selectivity of flow field‐flow fractionation and specificity of chemiluminescence detection make possible, in a single run with very short analysis time, the simultaneous, high sensitivity detection of the different enzymes linked to beads of different size.
Separation of racemic compounds on amylose and cellulose dimethylphenylcarbamate‐coated zirconia in HPLC
Authors: Park Jung Hag , Whang Young Chul , Jung Yun Jung , Okamoto Yoshio , Yamamoto Chiyo , Carr Peter W. , McNeff Clayton V. 
Published: October 2003

AbstractZirconia particles are a very robust material and have received considerable attention as a stationary phase support for HPLC. Chromatographic performances of ADMPC‐ and CDMPC‐coated zirconia as chiral stationary phases (CSPs) were compared by measuring the chiral discrimination of a set of 14 racemic compounds on the two columns. On the whole CDMPC‐zirconia showed better chiral selectivity for the test compounds than ADMPC‐zirconia. The two CSPs show complementary chiral recognition capability for the types of racemates studied. Chiral selectivities of ADMPC‐ and CDMPC‐coated zirconia were also compared with those of ADMPC‐ and CDMPC‐coated silica. The zirconia CSPs exhibited comparable and sometimes better enantioselectivity than the corresponding silica CSPs.
Separation and determination of sulfonamides in pharmaceutical preparations by a microfluidic capillary electrophoresis system with a continuous sample introduction interface
Authors: Fan Liu Yin , Chen Hong Li , Chen Xing Guo , Hu Zhi De 
Published: October 2003

AbstractA simple, rapid microfluidic capillary electrophoresis system with a continuous sample introduction interface is described in the present paper. The interface with an H‐channel structure was produced using a non‐lithographic approach. The H‐channel structure fixed on a planar plastic base utilized a horizontal 6.5‐centimeter‐long separation capillary with two vertical sidearm tubes on each end that served as inlet and outlet flow‐through electrode reservoirs. The inlet reservoir also functioned as interface for coupling to the FI system. The performance of the system was demonstrated in the separation and determination of trimethoprim (TMP), sulfadiazine (SDZ), and sulfamethoxazole (SMZ) with UV detection at 214 nm, achieving baseline separation within 2.5 min. The sample throughput rate can reach up to 30 samples h–1. The repeatability (defined as relative standard deviation, RSD) was 2.23%, 1.19%, 2.64% with peak height evaluation and 2.43%, 1.46%, 3.58% for peak area evaluation, respectively. The limits of detection (S/N = 3) were 0.17 μg/mL, 1.05 μg/mL, and 1.28 μg/mL for TMP, SDZ, and SMZ, respectively. This technique has been applied to the analysis of two commercial pharmaceutical preparations containing TMP, SDZ, and SMZ for the first time and has achieved satisfactory results.
Analysis of eflucimibe and related impurities by highly sensitive liquid chromatography‐electrospray‐tandem mass spectrometry
Authors: Mesplet Nathalie , Morin Philippe , Ribet Jean‐Paul 
Published: October 2003

AbstractEflucimibe (F 12511) is a new and promising acyl‐coenzyme A cholesterol O‐acyl‐transferase (ACAT) inhibitor, developed at the Pierre Fabre Research Center for the treatment of atherosclerosis. Owing to the synthetic pathway, residual impurities may be present (at very low levels) in the final product, which is currently analysed by high‐performance liquid chromatography (HPLC) with UV detection. In this work, a faster, specific, and sensitive analytical method has been developed for the determination of eflucimibe and its four related impurities. Electrospray‐tandem mass spectrometry (ESI‐MS/MS) coupled with HPLC is demonstrated to efficiently enhance the detection limits (at least 1200‐fold), within a 4‐minute run time. After optimisation of the ESI and MS/MS parameters for each of the five compounds, quantitative analysis was performed in the multiple reaction monitoring (MRM) mode and the calibration curves yielded correlation coefficients (r ) greater than 0.9996. Finally, this method was successfully applied to the assay of a real batch sample.
Capillary electrochromatography of boswellic acids in Boswellia serrata Roxb.
Authors: Ganzera Markus , Stöggl Wolfgang M. , Bonn Günther K. , Khan Ikhlas A. , Stuppner Hermann 
Published: October 2003

AbstractCapillary electrochromatography (CEC) was utilized for the analysis of major boswellic acids in the resin of Boswellia serrata (Indian olibanum). Baseline separation of six acidic triterpenes was obtained using a 100 μm ID fused silica capillary filled with 3 μm Hypersil ODS material, and a mobile phase comprising of acetonitrile and aqueous 20 mM ammonium formate solution (pH 6.5) in the ratio of 9 : 1 (v : v). The influence of relevant parameters (stationary phase, composition of mobile phase, voltage, temperature) was investigated and optimized, so that a separation was feasible within 20 min. This optimized system was then successfully used for the quantitative determination of boswellic acids in plant material. Due to their different absorption maxima, the standard compounds were detected either at 210 or 254 nm. The resulting data were precise (δmax = 3.3% based on peak area) and in good agreement with results obtained by HPLC analysis of the same sample (δmax = 4.1% between CE and HPLC results). The qualitative and quantitative results obtained prove that CEC can be a useful tool for the reliable, accurate, and economic analysis of natural products in biological samples.
Pressurized capillary electrochromatography separation of peptides with strong cation exchange and hydrophilic interaction
Authors: Zhang Kai , Gao Ruyu , Jiang Zhengjin , Yao Chuanyi , Zhang Zhichao , Wang Qinsun , Yan Chao 
Published: October 2003

AbstractA pressurized capillary electrochromatography (pCEC) instrument with solvent gradient capability has been used for the separation of a peptide mixture. Retention mechanism and selectivity of the peptides were studied by pCEC using a strong cation exchange (SCX) column. The effects of applied voltage, supplementary pressure, organic modifier concentration, ionic strength, and pH value on pCEC separation were investigated. It was found that the retention mechanism of the peptides in this system is based on a mixed mode of hydrophilic interaction, strong cation exchange, and electrophoresis. Compared with the separation results obtained by reverse phase pCEC and capillary electrophoresis (CE), this mixed‐mode pCEC is more powerful for the separation of hydrophilic peptides with similar charge‐to‐mass ratio.
Effects of Er:YAG and Nd:YAG laser irradiation on radicular dentine permeability using different irrigating solutions
Authors: Brugnera Aldo , Zanin Fátima , Barbin Eduardo L. , Spanó Julio C. , Santana Reginaldo , Pécora Jesus D. 
Published: October 2003

AbstractBackground and ObjectivesTo evaluate the effect of Er:YAG and Nd:YAG laser on radicular dentine permeability when using distilled and deionized water and 1% NaClO as irrigating solutions.Study Design/Materials and MethodsThirty human maxillary canines were divided randomly into six groups. The root canals were instrumented with K files and the step‐back technique. Group I, irrigation with distilled and deionized water; Group II, irrigation with 1% NaClO; Group III, irrigation with distilled and deionized water and Er:YAG laser application (140 mJ input, 61 mJ output 15 Hz, 300 pulses, and 42 J); Group IV, irrigation with 1% NaClO and Er:YAG laser application (same parameters as Group III); Group V, irrigation with distilled and deionized water and Nd:YAG laser application (150 mJ, 15 Hz, 2,25 W); Group VI, irrigation with 1% NaClO and Nd:YAG laser application (same parameters as Group V). During laser application the teeth were always filled with the irrigating solution. The tip was withdrawn gently in helicoidal movement from the apex to the cervical portion. The teeth were processed for histochemical evaluation.ResultsThe Tukey test showed that the cervical and middle thirds were statistically similar (P > 0.05) and significantly greater than the apical third (P < 0.05). The Scheffé test showed significantly greater dentine permeability in root canals in which water and Er:YAG laser were used and were significantly different from the other treatments (P < 0.05).ConclusionsThe use of distilled and deionized water and Er:YAG laser showed the greater increase of dentine permeability. The use of 1% NaClO with Nd:YAG laser, distilled, and deionized water with Nd:YAG laser and the use of water increased dentine permeability less than the other groups. The use of 1% NaClO with and without Er:YAG laser application were positioned intermediately among the treatments. Lasers Surg. Med. 33:256–259, 2003. © 2003 Wiley‐Liss, Inc.
Effects of dehydration on the optical properties of in vitro porcine liver
Authors: Zhu Dan , Luo Qingming , Cen Jian 
Published: October 2003

AbstractBackground and ObjectivesIt is of crucial importance to determine the effects of dehydration on the optical properties of tissue so that optimization of therapy and device for laser applications in medicine can be made.Study Design/Materials and MethodsAfter being incubated directly or indirectly in an oven of 37°C for different periods of time, the porcine liver samples were weighed with an electronic scale and their optical properties were measured by a double integrating sphere system.ResultsWhen samples were incubated directly for 20 hours, the average weight loss was 68.5% ± 1.2%, and the absorption coefficient and scattering coefficient increased 146.1% ± 26.9% and 10.8% ± 1.1%, respectively. In comparison, there was only 21.5% ±  1.0% of water loss for the control samples, and the absorption coefficient increased 30.7% ± 7.6%, while the reduced scattering coefficient increased 386.5% ± 29.7%. The effective attenuation coefficients increased 111% and 103% for dehydration group and control group, respectively.ConclusionsThe absorption coefficient and effective attenuation coefficient increase with dehydration level of tissue. However, there is no direct correlation between dehydration and reduced scattering coefficient. Lasers Surg. Med. 33:226–231, 2003. © 2003 Wiley‐Liss, Inc.
Increase of enamel fluoride retention by low fluence argon laser in vivo
Authors: Nammour S. , Demortier G. , Florio P. , Delhaye Y. , Pireaux J.‐J. , Morciaux Y. , Powell L. 
Published: October 2003

AbstractBackground and ObjectivesThe aim of this in vivo study was to investigate if argon laser irradiation of enamel can increase the retention of fluoride.Study Design/Materials and MethodsNinety‐eight teeth in 12 patients were randomly divided into three groups: (1) EF group: 40 teeth were only treated by fluoride gel (application for 5 minutes followed by 1 minute rinsing with distilled water). (2) EFL group: 40 teeth were treated the same way as in the EF group but they were lased after fluoridation. (3) E group of 18 teeth were kept without any treatment and considered as reference. In order to quantify the fluoride content in the enamel samples, the teeth were analyzed by proton beam delivered by a tandem accelerator (PIγE, particle induced gamma‐ray emission). The fluoride content of enamel surface is not homogeneous. Therefore, it is necessary to analyze the same enamel area after each treatment. Each tooth was maintained in a fixed tooth holder which was designed to analyze the tooth enamel surface at the same place (1 mm2 and around 20 μm in depth) after various treatments. A low energy density of argon laser beam was used: 10.74 J/cm2, 30 seconds of irradiation time and 340 m W of output power.ResultsThe results after 7 days showed that the lased enamel still retained 157.4 ± 23.371 ppm or 42.29% of fluoride after fluoridation process whereas the unlased enamel retained 45.59 ± 9.377 ppm or 12.25% of fluoride.ConclusionsWe concluded that the use of argon laser at low energy density (10.74 J/cm2) significantly increases the fluoride retention in lased enamel which had approximately three times more fluoride than the unlased enamel. Lasers Surg. Med. 33:260–263, 2003. © 2003 Wiley‐Liss, Inc.
Imaging tissue response to electrical and photothermal stimulation with nanometer sensitivity
Authors: Akkin Taner , Davé Digant P. , Youn Jong‐In , Telenkov Sergey A. , Rylander H. Grady , Milner Thomas E. 
Published: October 2003

AbstractBackground and ObjectivesTissue response to thermal, electrical, or chemical stimuli are important in the health and survival of tissue. We report experimental results to assess tissue response to various stimuli using a low coherence differential phase interferometer.Study Design/Materials and MethodsThe optical system utilized to measure tissue response is a novel fiber‐based phase sensitive optical low coherence reflectometer (PS‐OLCR). Inasmuch as the PS‐OLCR works with back‐reflected light, noninvasive sensing of tissue response to stimuli is possible. In addition to high lateral (∼10 μm) and longitudinal (∼10 μm) resolution, PS‐OLCR can measure sub‐wavelength changes in optical path‐length (Angstrom/nanometer range) by extracting the phase difference between interference fringes in two channels corresponding to orthogonal polarization modes.ResultsWhen light spatially splits into two polarization states, precise analysis of surface topography or tissue surface response such as swelling or collapse are possible. Time resolved measurements of nanometer‐scale path length changes in response to electrical and thermal stimuli are demonstrated using longitudinally delayed polarization channels.ConclusionsSince PS‐OLCR is a useful tool to detect ultra‐small path length changes, the system has potential to aid scientists in investigating important phenomena in biomaterials and developing useful diagnostic and therapeutic imaging modalities. Applications include tissue surface profilometry, measurement of tissue, and cell response to various stimuli, high‐resolution intensity and phase imaging. Lasers Surg. Med. 33:219–225, 2003. © 2003 Wiley‐Liss, Inc.
In vitro effects of pulsed holmium laser energy on canine uroliths and porcine cadaveric urethra
Authors: Wynn Victoria M. , Davidson Ellen B. , Higbee Russell G. , Ritchey Jerry W. , Ridgway Tisha D. , Bartels Kenneth E. , Lucroy Michael D. 
Published: October 2003

AbstractBackground and ObjectivesTo assess the effect of holmium laser energy on canine uroliths and porcine urethra.Study Design/Materials and MethodsUroliths of known composition and fresh cadaveric urethra were exposed to holmium laser energy. Urolith fragmentation times and depth of urethral lesions were determined.ResultsOverall mean fragmentation time was 11.8 ± 8.01 seconds. Magnesium ammonium phosphate (MAP) and urate uroliths had significantly shorter fragmentation times compared to other uroliths. Fragmentation time of MAP uroliths irradiated with 1.2 J/pulse was significantly longer than the fragmentation time of MAP uroliths irradiated with 0.3 J/pulse. Overall mean lesion depth for urethral specimens treated with 90° contact mode irradiation was significantly greater than overall mean lesion depth for specimens treated with 30° non‐contact mode.ConclusionsHolmium laser energy effectively fragmented canine uroliths and caused minimal urethral damage in vitro. Dogs with urolithiasis may represent a useful animal model for developing human lithotripsy procedures. Lasers Surg. Med. 33:243–246, 2003. © 2003 Wiley‐Liss, Inc.
Multicenter study of noninvasive radiofrequency for periorbital tissue tightening
Authors: Fitzpatrick Richard , Geronemus Roy , Goldberg David , Kaminer Michael , Kilmer Suzanne , Ruiz‐Esparza Javier 
Published: October 2003

AbstractBackground and ObjectivesThis 6‐month study evaluated the efficacy and safety of treatment with a nonablative radiofrequency (RF) device.Study Design/Materials and MethodsEighty‐six subjects received a single treatment with the ThermaCool TC™ System (Thermage, Inc., Hayward, CA) and were evaluated for 6 months after treatment.ResultsIndependent scoring of blinded photographs resulted in Fitzpatrick wrinkle score improvements of at least 1 point in 83.2% (99/119) of treated periorbital areas. Treating physicians, without reference to pre‐treatment photographs, noted improvements in 28.9% (48/166) of treatment areas. Fifty percent (41/82) of subjects reported being satisfied or very satisfied with periorbital wrinkle reductions. Objective photographic analysis showed that 61.5% (40/65) of eyebrows were lifted by at least 0.5 mm. Rates and duration of edema/erythema were very low (e.g., vs. ablative procedures). Overall 2nd‐degree burn incidence was 0.36% (21 per 5,858 RF applications). Three patients had small areas of residual scarring at 6 months.ConclusionsA single treatment with this RF tissue tightening (RFTT) device produces objective and subjective reductions in periorbital wrinkles, measurable changes in brow position, and acceptable epidermal safety. These changes were indicative of a thermally induced early tissue‐tightening effect followed by additional tightening over a time course consistent with a thermal wound healing response. Lasers Surg. Med. 33:232–242, 2003. © 2003 Wiley‐Liss, Inc.
Chain‐growth polycondensation of potassium 3‐cyano‐4‐fluorophenolate derivatives for well‐defined poly(arylene ether)s
Authors: Suzuki Yukimitsu , Hiraoka Shuichi , Yokoyama Akihiro , Yokozawa Tsutomu 
Published: October 2003

AbstractPolycondensation normally proceeds in a step‐growth reaction manner to give polymers with a wide range of molecular weights. However, the polycondensation of potassium 2‐alkyl‐5‐cyano‐4‐fluorophenolate (1) proceeded at 150°C in a chain polymerization manner from initiator, 4‐fluoro‐4′‐trifluoromethyl benzophenone (2), to give aromatic polyethers having controlled molecular weights and low polydispersities (Mw/Mn ⩽ 1.2). The resulting polycondensation of 1 had all of the characteristics of living polymerization and displayed a linear correlation between molecular weight and monomer conversion, maintaining low polydispersities. Sulfolane was a better solvent for chain‐growth polycondensation of 1 than other aprotic solvents. The polyether from 1 with a low polydispersity showed higher crystallinity than that with a broad molecular weight distribution, obtained by the conventional polycondensation of 1 without 2.
Curing under continuous microwaves (2 450 MHz) of thermosetting epoxy prepolymers: final statement
Authors: Alazard Patrick , Palumbo Michel , Gourdenne Albert 
Published: October 2003

AbstractAfter some recalls on the dielectric behavior of the organic materials, a parametrical study of the activation by continuous microwaves (2 450 MHz) of the curing reaction of an epoxy resin of DGEBA type in presence of diamino‐biphenyl‐methane used as crosslinking agent, is carefully described. The recording during the irradiation of the variations of the average temperature of the chemical medium and of the associated dielectric loss on the one hand, and the determination of the glassy transition temperature of the final networks on the other hand, allows optimization procedures of the electromagnetic treatment of the initial prepolymeric mixtures.
Synthesis and properties of thermally reversible polyesters
Authors: Yamanaka Toru , Kanomata Akinori , Inoue Toshihide 
Published: October 2003

AbstractThermally reversible polyesters were obtained by the ester formation reaction of thermoplastic polyesters with hydroxyl end groups and the diacid anhydride of tetra carboxylic acid as a thermally reversible chain extender. Typical example of the thermally reversible polyesters was obtained by the reaction of PBT (polyburylene terephthalate) and PMA (pyromellitic dianhydride). This material having twice as large molecular weight as the original PBT exhibited almost the same melt viscosity as the original. Also that thermally reversible chain extension reaction occurred without unfavorable side reaction such as cross‐linking. This material shows both good processability and superior mechanical properties due to its thermally reversible characters.
Synthesis of fully conjugated aromatic polyazomethine from AB‐type monomer using soluble precursor method
Authors: Matsumoto Toshihiko , Matsuoka Toshihiko , Suzuki Yoshitaka , Miyazawa Kenshi , Kurosaki Toshikazu , Mizukami Takayuki 
Published: October 2003

AbstractA new AB‐type monomer, N,N‐bistrimethylsilylated p‐aminobenz‐aldehyde diethyl acetal was prepared via three steps from p‐bromoaniline as a starting material. The two‐stage polymerization involving a soluble precursor polymer process gave a poly(p‐phenylenevinylene)‐type polyazomethine, poly(1,4‐phenylene‐nitrilomethylidyne). The first stage of polymerization was carried out in tetrahydrofuran or hexamethylphosphoramide containing water at room temperature. In the second stage, the polymer was thermally converted into the final polyazomethine by heating over 300°C to form a free‐standing film. The film was reddish brown and insoluble in common organic solvents. The investigation of the first‐stage products by means of MALDI‐TOF mass spectroscopy proved the oligomers with 4‐11 repeating units per molecule. From the 1H‐NMR analysis of the model reaction, the polymerization mechanism was found to be a stepwise polycondensation of 4‐diethoxymethylaniline which was formed by removal of two silyl groups of the monomer.
New monomers and polymers via Diels‐Alder cycloaddition
Authors: Rusanov Alexander L. , Shifrina Zinaida B. , Bulycheva Elena G. , Keshtov Mukhamed L. , Averina Marina S. , Fogel Yulia I. , Muellen Klaus , Harris Frank W. 
Published: October 2003

AbstractThe series of new bis(naphthalic anhydrides) was prepared through Diels‐Alder cycloaddition. The Diels‐Alder cycloaddition was used as a synthetic route to new phenylated monomers as well as to polymers. All polymers synthesized revealed to be soluble in a wide range of organic solvents such as toluene, THF, chloroform, and displayed high thermostability. Therefore, they can be processed easily and are promising candidates for advanced coating systems as well as for electrooptical applications.