bluuebunny/crossref_metadata_2025 huggingface dataset:
Process‐oriented knowledge management systems based on KM‐services: the PROMOTE® approach
Authors: Woitsch Robert , Karagiannis Dimitris
Published: October 2003

This article describes the PROMOTE® approach, to deﬁne and implement a Service‐Based Enterprise Knowledge Management System (E‐KMS) that has been developed during the EC‐funded project PROMOTE (IST‐1999‐11658). The aim is to deﬁne a modelling language that is used to analyse, document and implement an E‐KMS on the basis of so‐called Knowledge Management Processes (KMPs). KMPs deﬁne the knowledge interaction between knowledge workers in a process‐oriented manner and consists of activities that are supported by knowledge management key actions (KA) like searching, categorising or storing information. These knowledge management key actions are supported by Knowledge Management Services (KM‐Service). The prototype of PROMOTE® is brieﬂy mentioned to discuss the KMP‐models and the service based E‐KMS. Copyright © 2003 John Wiley & Sons, Ltd.
The General Motors' variation‐reduction adviser: an example of grassroots knowledge management development
Authors: Morgan Alexander P. , Cafeo John A. , Gibbons Diane I. , Lesperance Ronald M. , Sengir Gulcin H. , Simon Andrea M.
Published: October 2003

One approach to developing knowledge management systems is to seed the system in key communities of practice and then encourage its customization and spread throughout the enterprise by local (‘grassroots’) initiative. This has the beneﬁt of worker buy‐in and adaptation of the local systems to their workﬂows. The concept is that, in exchange for some loss of control and standardization, the grassroots systems will be used and appreciated and will grow into an enterprise‐wide system. In this paper, we discuss this approach and how it is emerging in General Motors' Variation‐Reduction Adviser, a manufacturing knowledgesharing and lessons‐learned system. Copyright © 2003 John Wiley & Sons, Ltd.
Business process semi‐automation based on business model management
Authors: Terai Koichi , Sawai Masahiko , Sugiura Naoki , Izumi Noriaki , Yamaguchi Takahira
Published: October 2003

It is important to respond to customers' requirements more rapidly than ever before due to the recent trend in e‐business and its technologies. In order to achieve an agile response, we have to manage business models, to reﬂect the changes in the models and to develop or modify IT systems for further chances. This paper proposes a management framework of layered enterprise models. The proposed framework consists of a business model repository and a software repository, and deﬁnes three different grain sizes of modeling layers, namely business modeling, business process modeling and business application modeling, in order to support business modeling and application development. This framework helps us to develop business application in incremental deployment of analysis, design, and implementation to execute business processes. We have implemented a prototype environment using Java. Each repository's contents are described using XML so that the repositories are interoperable. Copyright © 2003 John Wiley & Sons, Ltd.
Plasmapheresis as rescue therapy in accelerated acute humoral rejection
Authors: Abraham Kottarathil A. , Brown Catherine , Conlon Peter J. , Donohoe John , Hickey David P. , O'Neill Derek , Keogan Mary T. , Dorman Anthony M. , Walshe Joseph
Published: October 2003

Accelerated acute humoral rejection (AHR) continues to occur in renal transplantation despite improved crossmatching, with potentially devastating consequences. Between 1 June 1998 and 31 December 2000, 440 renal transplants were performed in our center. AHR was diagnosed by the demonstration of typical pathological features on renal histology and positive direct immunofluorescence or detection of anti‐HLA antibodies in serum. AHR developed in 20 (4.5%) of our renal transplant recipients, nine male and eleven female at an average of 16.3 days post transplantation. All of these patients had a negative current cytotoxic crossmatch prior to transplantation. The median serum creatinine at diagnosis was 5.96 mg/dL, and 83% of these individuals developed oliguric renal failure requiring dialysis after having initially attained good graft function (median of best serum creatinine before AHR was 2.64 mg/dL). The 18 recipients who had not infarcted their grafts at the time of diagnosis of AHR received plasmapheresis in conjunction with intensification of their immunosuppressive regimen. This regimen was successful in reversing AHR in 78% of those treated with apheresis. In the 14 responders, graft survival at 6 months was 100% and at 12 months was 91%. Median serum creatinine at 6 and 12 months was 1.26 and 1.33 mg/dL, respectively. Patients received an average of 8.1 plasma exchanges. However, responders received a significantly higher frequency of plasmapheresis (P = .0053), despite undergoing a similar number of exchanges overall. Plasmapheresis appears to be an effective modality for reversing AHR and maintaining graft function. J. Clin. Apheresis 18:103–110, 2003. © 2003 Wiley‐Liss, Inc.
Pulmonary function study of myasthenia‐gravis patients treated with double‐filtration plasmapheresis
Authors: Chiu Hou‐Chang , Yeh Jiann‐Horng , Chen Wei‐Hung
Published: October 2003

The aim of this study was to investigate the changes in pulmonary function tests for patients with myasthenia gravis (MG) after treatment with double filtration plasmapheresis (DFP) and to evaluate whether pulmonary function tests predict the efficacy of DFP treatment. Thirty‐five MG patients (20 females and 15 males, age range 21–69 years) underwent DFP for between four and eight consecutive sessions. Vital capacity (VC), maximal inspiratory pressure (Pimax), and MG score were measured before and after DFP. Based on the results of pulmonary function tests, the patients were divided into dyspnea (VC < 1.0 L or Pimax < −25 cm H2O) and control groups (VC > 1.0 L and Pimax > −25 cm H2O). The dyspnea group had a significantly better response to DFP treatment, reflected in the decrease of the MG‐score (P=0.0327), and the increase in VC value (P=0.0561). Higher clearance rates of acetylcholine receptor antibody (AchRAb) had a trend toward higher changes of VC. In conclusion, VC might better serve as a predictor for the effect of DFP in the dyspnea patient group because of better correlation with clinical improvement and AchRAb clearance. J. Clin. Apheresis 18:125–128, 2003. © 2003 Wiley‐Liss, Inc.
Stem cell mobilization by G‐CSF in solid and hematological malignancies: Single daily dose is better than split dose in obese patients
Authors: Çetin Türker , Arpaci Fikret , Özet Ahmet , Öztürk Bekir , Kömürcü Şeref , İhsan Uzar Ali , Yilmaz İlker , Beyzadeoĝlu Murat , Oysul Kaan , Ataergin Selmin , Kuzhan Okan , Pekel Aysel
Published: October 2003

In the past, variable results were reported for single daily and two divided daily doses of granulocyte colony‐stimulating factor (G‐CSF) in stem cell collection where no study exists investigating the effect of body mass index (BMI) on mobilization. The numbers of CD34+ cells collected were compared in 86 patients with solid or hematological malignancies receiving either single daily (14 μg/kg/day) G‐CSF (filgrastim) as group I (n=36) or two divided doses of G‐CSF daily (2 × 7 μg/kg/day) as group II (n = 50). Both groups were divided into subgroups according to their BMI as group a (BMI ≤25 kg/m2) and group b (BMI >25 kg/m2). Two groups were similar in terms of BMI, gender, and disease characteristics. All patients have received G‐CSF as a single or two divided doses subcutaneously and aphereses have been done on the 5th day. No significant difference in numbers of CD34+ cells between groups Ia and Ib, groups IIa and IIb, and groups Ia and IIa was found. On the other hand, the mean ratio and the number of CD34+ cells in group Ib were significantly higher than those of group IIb (0.58 ± 0.06% vs. 0.37 ± 0.26%, P = 0.01 and 3.67 ± 0.65 × 104/kg/ml vs. 1.92 ± 0.37 × 104/kg/ml, P= 0.02). In conclusion, in patients with BMI >25 kg/m2, once daily G‐CSF compared to split dose administration induces a greater number of CD34+ stem cell mobilization, which suggests the presence of a different pharmacokinetics in obese patients. J. Clin. Apheresis 18:120–124, 2003. © 2003 Wiley‐Liss, Inc.
Stationary and mobile phases in capillary electrochromatography (CEC)
Authors: Jiskra Jan , Claessens Henk A. , Cramers Carel A.
Published: October 2003

This review describes the state of the art of capillary electrochromatography (CEC). Properties of and interactions between stationary and mobile phases applied in CEC are described and discussed; developments in stationary phases, partly also monolithic stationary phases, are reviewed. Special attention is paid to the comparison of the behaviour of stationary and/or mobile phases under CEC versus HPLC conditions with respect to variables such as particle and pore size of the stationary phase, mobile phase composition, and temperature. These issues are discussed throughout the paper. A number of applications in CEC is presented as well.
Determination of conjugated dienes in petroleum products by supercritical fluid chromatography and ultraviolet detection
Authors: Albuquerque Flávio Cortiñas
Published: October 2003

A method for determining total conjugated dienes in petroleum products, such as catalytic or thermal cracking fractions, using supercritical fluid chromatography (SFC) is presented. The separation is carried out in one or two silica columns and with CO2 as mobile phase. The conditions of analysis are the same as used in group‐type analysis of diesel fuels by SFC (ASTM D 5186 standard method), except that UV detection at 240 nm is used. Hydrocarbons with two conjugated double bonds are the only substances eluting in the retention time range of the non‐aromatics that appreciably absorb UV radiation at this wavelength. This was confirmed by analyzing standards of olefins, isolated diolefins, and conjugated diolefins. Results are reported in mol L–1 of 1,3‐pentadiene. Several samples of different natures, such as fluid catalytic cracking liquid products and hydrotreated cracking naphthas, were successfully analyzed. The results correlate quite well with the respective diene values as determined by UOP method 326, although the slope and intercept were specific for each type of product.
Chemometrics in capillary electrophoresis. Part B: Methods for data analysis
Authors: Sentellas Sònia , Saurina Javier
Published: October 2003

Methods for data analysis in CE are addressed to extract relevant information contained in the electrophoretic responses. The main objectives of chemometrics in this field are the characterization of complex samples, the study of peak purity and deconvolution of comigrations, and the quantification of the analytes in poorly resolved peaks. In this paper, the application of chemometric techniques to data analysis is reviewed. The chemometric methods for the optimization of CE separations have been reviewed in Part A (see Sentellas and J. Saurina, Chemometrics in capillary electrophoresis. Part A: Methods for optimization).
Sedimentation field‐flow fractionation and granulometric analysis of PLGA microspheres
Authors: Faisant Nathalie , Battu Serge , Senftleber Fred , Benoit Jean‐Pierre , Cardot Philippe J. P.
Published: October 2003

Sedimentation field flow fractionation operated in the steric hyperlayer mode was used to obtain fractions of defined characteristics from crude samples of poly(D,L‐lactic‐co‐glycolic acid) microspheres which were polydisperse in size. In less than ten minutes, Sedimentation Field Flow Fractionation (SdFFF) separation yielded three analytical fractions of very different size and particle size distribution (PSD) characteristics, as determined by granulometric analyses (Coulter Counter® and image analysis of SEM). A crude sample (average size = 45 μm, 105% size polydispersity index) was separated into fractions of 73 μm, 56 μm, 8 μm average diameters which showed a PSD of 39%, 33%, 30%, respectively. Our results demonstrated that SdFFF used in conjunction with particle size analysis offers a new approach to laboratory scale production of drug vectors of a specified average size and reduced size dispersity. In the future, this could be used to select the most convenient particles for drug loading and release.
Influence of the organic modifier and the ion‐pairing agent in the mobile phase on the separation of soya bean proteins by perfusion liquid chromatography. Analysis of commercial dairylike soya bean products using multivariate techniques
Authors: Delgado Susana , Concepción García M. , Marina M. Luisa , Torre Mercedes
Published: October 2003

The influence of the nature and concentration of the organic modifier and the ion‐pairing agent in the mobile phase on the separation of soya bean proteins by perfusion reversed‐phase high‐performance liquid chromatography was investigated. Acetonitrile, methanol, and isopropanol were used as organic modifiers, and trifluoroacetic acid (TFA), heptafluorobutyric acid (HFBA), morpholine (MP), and mixtures thereof as ion‐pairing agents. Different linear binary gradients were tried and the best separations of soya bean proteins (in terms of number of peaks, total peak area, and resolution) were obtained when using isopropanol and acetonitrile as organic modifiers and mixtures of TFA and MP as ion‐pairing agents. Two elution gradients were chosen in order to achieve the characterisation of dairylike soya bean products on the basis of their chromatographic profiles by multivariate techniques: an isopropanol‐water gradient, 0.1% (v/v) TFA‐0.2% (v/v) MP in both phases, 3–20% B in 3.5 min and 20–45% B in 1.5 min (flow rate, 3 mL/min), and an acetonitrile‐water gradient, 0.1% (v/v) TFA‐0.1% (v/v) MP in both phases, 5–25% B in 1.75 min and 25–45% B in 1.75 min (flow rate, 4 mL/min). Finally, the isopropanol‐water gradient was also applied to the analysis of soya bean proteins in commercial dairylike soya bean products by using multivariate techniques.
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

On‐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

Zirconia 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

A 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

Eflucimibe (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

Capillary 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

A 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

Background and Objectives

To 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 Methods

Thirty 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.

Results

The 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).

Conclusions

The 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

Background and Objectives

It 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 Methods

After 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.

Results

When 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.

Conclusions

The 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

Background and Objectives

The 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 Methods

Ninety‐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.

Results

The 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.

Conclusions

We 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

Background and Objectives

Tissue 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 Methods

The 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.

Results

When 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.

Conclusions

Since 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

Background and Objectives

To assess the effect of holmium laser energy on canine uroliths and porcine urethra.

Study Design/Materials and Methods

Uroliths of known composition and fresh cadaveric urethra were exposed to holmium laser energy. Urolith fragmentation times and depth of urethral lesions were determined.

Results

Overall 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.

Conclusions

Holmium 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

Background and Objectives

This 6‐month study evaluated the efficacy and safety of treatment with a nonablative radiofrequency (RF) device.

Study Design/Materials and Methods

Eighty‐six subjects received a single treatment with the ThermaCool TC™ System (Thermage, Inc., Hayward, CA) and were evaluated for 6 months after treatment.

Results

Independent 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.

Conclusions

A 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.
What does polycondensation mean?
Authors: Kricheldorf Hans R.
Published: October 2003

This contribution has the function of an introduction to the entire volume. It deals with several fundamental definitions and classifications related to the chemistry of polycondensation processes, and it includes modifications of the classical theory of step‐growth polymerizations.
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

Polycondensation 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

After 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

Thermally 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

A 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

The 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.
Synthesis and characterization of multiblock copolyesters containing poly(dimethylsiloxane) in the soft segments
Authors: El Fray Miroslawa , Altstaedt Volker
Published: October 2003

Synthesis and thermal properties of poly(aliphatic/aromatic‐ester) copolymers containing additionally poly(dimethylsiloxane) (PDMS) chains in the soft segments are discussed. A two step method of transesterification and polycondensation from the melt was carried out in a presence of magnesium‐titanate catalyst. An aliphatic dimer fatty acid was used as a component of the soft segments while poly(butylene terephthalate) (PBT) constituted the hard blocks. Effectiveness of the incorporation of PDMS into polymer chain was confirmed by the Soxhlet extraction and infrared spectroscopy of an excess of 1,4‐butane diol destilled off from the polycondensation reaction. Multiblock copolymers showed microphase separation as determined by differential scanning calorimetry. Incorporation of a small amount of PDMS (up to 14.5 wt.‐%) into polymer chain containg low concentration of hard segments of PBT lead to decrease in crystallinity of such copolymers. This may indicate that semicrystalline PBT are dissolved in the amorphous matrix of the soft segments.
Synthesis and properties of segmented copolymers of polyphenylene ether and tetra‐amide units
Authors: Krijgsman Josien , Feijen Jan , Gaymans Reinoud J.
Published: October 2003

Copolymers of telechelic poly(2,6‐dimethyl‐1,4‐phenylene ether) segments with terephthalic methyl ester endgroups (PPE‐2T, 3100 g/mol), uniform crystallizable tetra‐amide units based on nylon‐6,T (T6T6T, 13 wt%) and dodecanediol (C12) as an extender were made via a polycondensation reaction. The PPE‐2T/C12/T6T6T copolymers are semi‐crystalline materials with a glass transition temperature (Tg) of 169°C, a melting temperature (Tm) of 268°C and a very high Tg/Tm ratio of 0.82. The modulus is high up to the Tg and the modulus in the rubbery plateau after injection moulding is 10 MPa. The materials are slightly transparent and have good solvent resistance, low water absorption and good processability. With DSC it was calculated that the crystallinity of T6T6T in the copolymer is around 70%. The undercooling (Tm‐Tc) as measured by DSC is 18°C at a cooling rate of 20°C/min. With WAXD it was shown that the tetra‐amide units remain partially organized in the melt.
Synthesis and properties of poly(butylene terephthalate)‐poly(ethylene oxide)‐poly(dimethylsiloxane) block copolymers
Authors: Dahrouch M. , Schmidt A. , Leemans L. , Linssen H. , Götz H.
Published: October 2003

chemical structure image

Poly(butylene terephthalate)‐poly(ethylene oxide)‐poly(dimethyl siloxane)‐poly(ethylene oxide) block copolymers, (PBT‐PEO‐PDMS‐PEO)m, are synthesized by polycondensation (PC) of dimethylterephtalate (DMT), 1,4‐butanediol (BDO) and PEO‐PDMS‐PEO. The soft block has been incorporated from 10 to 70 wt‐%; the total molecular weight (MW) of the block‐copolymers amounts to 16000 ‐ 20000 g/mol.

One major problem of polyether‐PBT thermoplastic elastomers is their poor thermo‐oxidative stability. Due to the excellent heat stability of PDMS, the resistance of this new thermoplastic elastomer against thermo‐oxidative degradation has been increased 80 %!

From differential scanning calorimetry (DSC) and dynamic mechanical thermal analysis (DMTA) in the PEO‐PDMS‐PEO based COPEs, three phases can be distinguished. Besides the crystalline PBT phase, an amorphous mixed phase of PBT and PEO and an almost pure PDMS phase have been found. Due to the high concentration of the mixed PBT‐PEO phase, the low temperature modulus and the glass transition temperature, Tg, are not dominated by the pure PDMS phase (Tg = −114°C). Depending on the amount of PBT and PEO present, the main glass transition lies in the range of −50°C to 50°C.
Synthesis and characterization of poly(ethylene glycol) methyl ether endcapped poly(ethylene terephthalate)
Authors: Lin Qin , Unal Serkan , Fornof Ann R. , Wei Yuping , Li Huimin , Armentrout R. Scott , Long Timothy E.
Published: October 2003

Linear and branched poly(ethylene terephthalate) (PET) copolymers with polyethylene glycol) (PEG) methyl ether (700 or 2000 g/mol) end groups were synthesized using conventional melt polymerization. DSC analysis demonstrated that low levels of PEG end groups accelerated PET crystallization. The incorporated PEG end groups also decreased the crystallization temperature of PET dramatically, and copolymers with a high content of PEG (>17.6 wt%) were able to crystallize at room temperature. Rheological analysis demonstrated that the presence of PEG end groups effectively decreased the melt viscosities and facilitated melt processing. XPS and ATR‐FTIR revealed that the PEG end groups tended to aggregate on the surface, and the surface of compression molded films containing 34.0 wt% PEG were PEG rich (85 wt% PEG). PEG end‐capped PET (34.0 wt% PEG) and PET films were immersed into a fibrinogen solution (0.7 mg/mL BSA) for 72 h to investigate the propensity for protein adhesion. XPS demonstrated that the concentration of nitrogen (1.05%) on the surface of PEG endcapped PET film was statistically lower than PET (7.67%). SEM analysis was consistent with XPS results, and revealed the presence of adsorbed protein on the surface of PET films.
Synthesis and properties of dendritic polymers based on natural amino acids
Authors: Bilibin Alexander , Zorin Ivan , Saratovsky Sergey , Moukhina Irina , Egorova Galina , Girbasova Nina
Published: October 2003

Different approaches, including polycondensation, polymerization, polymer analog condensation, and ionic binding have been investigated for synthesis of amino acid‐based dendritic polymers. It was shown that a growth of dendrons generation prevents obtaining of products with high polymerization degree in polycondensation and polymerization procedures. In polymer analog condensation a growth of dendrons generation leads to considerable decrease of polymer analog reaction rate as well as substitution degree. Degree of ionic binding depends on a strength of ionogenic groups and dendrns generation.
Synthesis and characterization of hyperbranched aromatic polyamide copolymers prepared from AB2 and AB monomers
Authors: Jikei Mitsutoshi , Fujii Ken , Kakimoto Masa‐aki
Published: October 2003

A series of hyperbranched aromatic polyamide copolymers has been prepared and characterized from direct polycondensation of AB2 and AB monomers. Structure of the monomers and the molar ratio of AB2/AB showed strong influence on the properties of resulting copolymers. A small amount of AB2 branching unit improved markedly the solubility of the resulting copolymer. Mark‐Houwink parameters of the copolymers were essentially independent of the mole ratio of the monomers. The physical and mechanical properties of resulting copolymers were influenced not only by the mole ratio of monomers, but also by the structure of the monomers employed.
Hyperbranched polyimides prepared by ideal A2+B3 polymerization, non‐ideal A2+B3 polymerization and AB2 self‐polymerization
Authors: Hao Jianjun , Jikei Mitsutoshi , Kakimoto Masa‐aki
Published: October 2003

In this paper, hyperbranched polyimides having the same repeating unit were synthesized by employing ideal A2+B3 polymerization, non‐ideal A2+B3 polymerization and AB2 self‐polymerization methods. The polymerization behavior, polymer properties were compared for three methods. Hyperbranched polyimides by ideal A2+B3 polymerization, non‐ideal A2+B3 polymerization and AB2 self‐polymerization methods show apparent difference in many physical properties, such as inherent viscosity, glass transition temperature, and film formation behavior etc. The hyperbranched polymers by the non‐ideal A2+B3 polymerization are suitable for smooth, flexible and self‐standing film preparation, which provides useful information for hyperbranched polymers toward self‐standing materials.
Synthesis and characterisation of branched polyarylethers
Authors: Weber Martin , Charoensirisomboon Piyada
Published: October 2003

Polyarylethers (Polysulfone: PSU, Polyethersulfone: PES) belong to the group of high performance polymers, having high glass transition temperature as well as high continuous use temperature. As a consequence of their high glass transition temperature, these polymers display high melt viscosity, which limits the number of accessible applications. Since the conventional methods to improve the flow characteristics are limited, the influence of branching by incorporation of the tri‐functional monomer 1,1,1‐Tris‐(4‐hydroxyphenyl)ethane (THPE) on the flow and the mechanical performance of PES was studied.

Branching enhances the flow of Polyethersulfone significantly, but has a deleterious effect on the toughness, especially Charpy impact and tensile elongation.