bluuebunny/crossref_metadata_2025 huggingface dataset:
IPL technology: A review
Authors: Raulin Christian , Greve Bärbel , Grema Hortensia
Published: January 2003

Background and Objectives

Intense pulsed light (IPL) systems are high‐intensity light sources, which emit polychromatic light. Unlike laser systems, these flashlamps work with noncoherent light in a broad wavelength spectrum of 515–1,200 nm. These properties allow for great variability in selecting individual treatment parameters and adapting to different types of skin types and indications. The purpose of this article was to critically review international medical publications of the many indication in which IPL technology can be used, including our own evaluations and experiences.

Study Design/Materials and Methods

The range of therapeutic uses for high‐intensity flashlamps was reviewed, ranging from benign cavernous hemangiomas, benign venous malformations, essential telangiectasias, leg telangiectasias, poikiloderma of Civatte, and port‐wine stains to pigmented lesions, cosmetically undesired hypertrichosis, and facial rhydids. The relative benefits and risks were discussed in detail and compared with other laser systems.

Results

Because of the wide spectrum of potential combinations of wavelengths, pulse durations, pulse frequency, and fluences, a great deal of experience is required when using IPL technology. Proper patient selection and critical diagnostics serve to keep the adverse effects of the treatment to a minimum.

Conclusions

The distinctive technical conditions involved combine to make IPL technology an alternative and auxiliary treatment option to existing laser systems and conventional therapies. Lasers Surg. Med. 32:78–87, 2003. © 2003 Wiley‐Liss, Inc.
Measurements of laser light attenuation following cryogen spray cooling spurt termination
Authors: Edris Ahmad , Choi Bernard , Aguilar Guillermo , Nelson J. Stuart
Published: January 2003

Background and Objectives

Cryogen spray cooling (CSC) is used to minimize the risk of epidermal damage during laser dermatological surgery. However, while CSC can protect the epidermis from non‐specific thermal damage, the cryogen film on the skin surface may pose a potential problem of laser light attenuation due to optical scattering.

Study Design/Materials and Methods

This study is focused on measuring the light transmittance changes that occur following cryogen spurt termination. The wavelengths studied were chosen for their clinical relevance to treatment of hypervascular skin lesions (594 nm) and laser‐assisted hair removal (785 nm). Following delivery of cryogen spurts to the surface of an epoxy skin phantom, continuous records of light transmittance for 594 and 785 nm were obtained using an integrating sphere‐based light collection apparatus.

Results

Shortly after spurt termination, there was negligible light attenuation by the cryogen film at the two wavelengths studied.

Conclusions

For the typical clinical use of a 30 milliseconds spurt duration and 30 milliseconds delay between spurt termination and delivery of the laser pulse, a minimum average transmittance value of ∼97% was measured. Lasers Surg. Med. 32:143–147, 2003. © 2003 Wiley‐Liss, Inc.
Analysis of epidermal protection using cold air versus chilled sapphire window with water or gel during 810 nm diode laser application
Authors: Chang C.W. David , Reinisch Lou , Biesman Brian S.
Published: January 2003

Background and Objectives

Many cutaneous laser devices incorporate a temperature‐based epidermal protection system to minimize surface damage while continuing to affect targeted tissue. The use of cold air is a new technique to aid in epidermal protection during the application of cutaneous lasers. This study investigates the efficacy of cold air versus chilled sapphire in regards to epidermal preservation when used with an 810 nm diode laser.

Study Design/Material and Methods

White‐haired pink piglets and dark‐haired pigmented piglets were treated using the 810 nm diode laser in conjunction with either (1) no cryogen protection; (2) cold air alone; (3) chilled sapphire window alone; (4) cold air with water/gel; or (5) chilled sapphire window with water/gel. Laser fluence was varied by adjusting laser duration time while maintaining the intensity at 60 W. Biopsies were obtained from the sacrificed animals, stained with Masson's trichrome, and analyzed for extent of epidermal damage.

Results

Among white‐haired pink pigs, the cold air afforded the same degree of epidermal preservation as the chilled sapphire window. Epidermal protection was further enhanced with the addition of either gel or water. Among dark‐haired pigmented pigs, the chilled sapphire window alone likewise provided significant epidermal protection, although the cold air alone did not. However, with the addition of water/gel, epidermal preservation was demonstrated in both.

Conclusions

Cold air is an effective means in promoting epidermal preservation, though slightly inferior to the chilled sapphire window on darkly pigmented subjects. Combining either method with water or gel further enhances surface protection, enabling safe use of higher fluences. Lasers Surg. Med. 32:129–136, 2003. © 2003 Wiley‐Liss, Inc.
Newly designed hydrogel with both sensitive thermoresponse and biodegradability
Authors: Yoshida Takatsune , Aoyagi Takao , Kokufuta Etsuo , Okano Teruo
Published: February 2003

The synthesis and characterization of thermoresponsive hydrogels on the basis of N‐isopropylacrylamide (IPAAm) copolymers crosslinked with biodegradable poly(amino acids) are described. This hydrogel was prepared with two kinds of reactive IPAAm‐based copolymers containing poly(amino acids) as the side‐chain groups and activated ester groups. We introduced the graft chains by decarboxylation polymerization of amino acid N‐carboxyanhydrides initiated from lateral amino groups in the PIPAAm copolymer. The hydrogels easily crosslinked with degradable poly(amino acid) chains by only mixing the copolymer aqueous solutions. The gelling method in this study would provide some of the following innovative features: (1) no necessary removal of unreacted monomers and so forth, (2) simpler loading of drugs into the hydrogels (only mixing when gelling), and (3) easier insertion into the body. On the basis of the swelling ratio measurement of the hydrogel, large volume changes dependent on temperature changes were observed. Moreover, the enzymatic temperature‐dependent degradation was confirmed. The results suggested that these hydrogels could be used for an injectable or implantable matrix of temperature‐modulated drug release. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 779–787, 2003
Synthesis and characterization of two novel star blocks: tCum[poly(isobutylene‐b‐norbornadiene)]3 and tCum[poly(norbornadiene‐b‐isobutylene)]3
Authors: Peetz Ralf M. , Moustafa Ahmed F. , Kennedy Joseph P.
Published: February 2003

Two structurally closely related three‐arm star blocks were synthesized and characterized: tCum(PIB‐b‐PNBD)3 and tCum(PNBD‐b‐PIB)3 [where tCum (tricumyl) stands for the phenyl‐1,3,5‐tris(‐2‐propyl) fragment and PIB and PNBD are polyisobutylene and polynorbornadiene, respectively]. The syntheses were accomplished in two stages: (1) the preparation of the first (or inner) block fitted with appropriate chlorine termini capable of initiating the polymerization of the second (or outer) block with TiCl4 and (2) the mediation of the polymerization of the second block. Therefore, the synthesis of tCum(PIB‐b‐PNBD)3 was effected with tCum(PIB‐Clt)3 [where Clt is tert‐chlorine and number‐average molecular weight (Mn) = 102,000 g/mol] by the use of TiCl4 and 30/70 CH3Cl/CHCl3 solvent mixtures at −35 °C. PNBD homopolymer contamination formed by chain transfer was removed by selective precipitation. According to gel permeation chromatography, the Mn's of the star blocks were 107,300–109,200 g/mol. NMR spectroscopy (750 MHz) was used to determine structures and molecular weights. Differential scanning calorimetry (DSC) indicated two glass‐transition temperatures (Tg's), one each for the PIB (−65 °C) and PNBD (232 °C) phases. Thermogravimetric analysis thermograms showed 5% weight losses at 293 °C in air and at 352 °C in N2. The synthesis of tCum(PNBD‐b‐PIB)3 was achieved by the initiation of isobutylene polymerization with tCum(PNBD‐Clsec)3 (where Clsec is sec‐chlorine and Mn = 2900 g/mol) by the use of TiCl4 in CH3Cl at −60 °C. DSC for this star block (Mn = 14,200 g/mol) also showed two Tg's, that is, at −67 and 228 °C for the PIB and PNBD segments, respectively. It is of interest that the Clsec terminus of PNBD, , readily initiated isobutylene polymerization. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 740–751, 2003
Cationic polymerization of norbornadiene
Authors: Peetz Ralf M. , Moustafa Ahmed F. , Kennedy Joseph P.
Published: February 2003

The polymerization of norbornadiene (NBD) initiated by the 2‐chloro‐2,4,4‐trimethylpentane/titanium tetrachloride system was investigated. Efforts were made to develop conditions for the living polymerization of NBD by the use of proton trap and electron donor in the −35 to −60 °C range however this objective was only partially attained. The molecular weights increased linearly with conversion, and the rate was first‐order in confirmed monomer concentration up to approximately 25%; however, chain transfer became operational beyond this range. The microstructure of polynorbornadiene (PNBD) was investigated by high‐resolution 1H and 13C NMR spectroscopy. According to these techniques, the chain consisted of about equal amounts of exo/exo and exo/endo connected tricyclic repeat units. The head and tail groups were identified and quantitated, and this led to absolute molecular weight determination by integration. Molecular weights obtained by this method and by gel permeation chromatography (relative to polyisobutylene standards) were in good agreement. NMR spectroscopy indicated the presence of small but still identifiable amounts of branching units and their structures. The plot of the glass‐transition temperature against the reciprocal of the number‐average molecular weight was linear and yielded a glass‐transition temperature of 323 °C for the infinite molecular weight polymer. According to thermogravimetric analysis, PNBD was stable up to approximately 250 °C and showed a 5% weight loss at approximately 335 °C. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 732–739, 2003
Catalytic‐chain‐transfer polymerization of styrene revisited: The importance of monomer purification and polymerization conditions
Authors: Roberts G. Evan , Heuts Johan P. A. , Davis Thomas P.
Published: February 2003

The cobaloxime‐mediated catalytic‐chain‐transfer polymerization of styrene at 60 °C was studied with an emphasis on the effects of monomer purification and polymerization conditions. Commonly used purification methods, such as column chromatography and simple vacuum distillation, were not adequate for obtaining kinetic data to be used in mechanistic modeling. A purification regime involving inhibitor removal with basic alumina, followed by polymerization of the styrene in the presence of the cobaloxime and subsequent vacuum distillation, was found to be essential to this end. It was then possible to quantitatively investigate effects such as the initiator concentration and conversion dependencies of the apparent chain‐transfer constant that resulted from the occurrence of cobalt–carbon bond formation. A value of about 9 × 103 was found for the true chain‐transfer constant to cobaloxime boron fluoride, that is, its value in the absence of cobalt–carbon bond formation. Furthermore, previous predictions were confirmed: the measured chain‐transfer constant decreased with increasing initiator concentration and conversion. Finally, it was confirmed that the presence of light increased the amount of free Co(II) catalyst in agreement with other studies. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 752–765, 2003
Fluorescent polymer particles by emulsion and miniemulsion polymerization
Authors: Tronc Frédéric , Li Mei , Lu Jianping , Winnik Mitchell A. , Kaul Bansi Lal , Graciet Jean‐Christophe
Published: February 2003

We describe the synthesis and characterization of latex particles labeled with a brightly fluorescent yellow dye (HY) based on the benzothioxanthene ring structure. Three dye derivatives were synthesized with different spacers connecting the HY nucleus to a methacrylate group. For one of the dyes (HY2CMA, rA), we show that the reactivity ratios with styrene (rA = 0.71, rB = 0.25) and butyl methacrylate (rA = 0.87, rB = 0.14) should lead to random dye incorporation if the amount of dye in the feed is small. Seeded emulsion polymerization fails to lead to significant dye incorporation unless large amounts of nonionic surfactant are present. In contrast, miniemulsion polymerization worked well to yield latex particles of polystyrene, poly(butyl methacrylate), and poly(methyl methacrylate) with high monomer conversion and essentially quantitative dye incorporation. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 766–778, 2003
Real‐time Fourier transform infrared study of the free‐radical ultraviolet‐induced polymerization of a hybrid sol–gel. II. The effect of physicochemical parameters on the photopolymerization kinetics
Authors: Soppera O. , Croutxé‐Barghorn C.
Published: February 2003

Free‐radical photocurable hybrid sol–gel materials have gained special interest during the last decades. Compared to thermally processed materials, they present the advantages of fast curing, low energy consumption, and spatiotemporal control of the reaction. Although comprehension of the photochemical step is fundamental, little is known about the characteristic of photochemistry in this kind of material. Real‐time Fourier transform infrared spectroscopy was used to study the photopolymerization of a hybrid sol–gel upon ultraviolet irradiation. Various photoinitiator systems were tested for their efficiency in inducing the polymerization of pendant polymerizable moieties anchored on a partially condensed silicate network. The presence of O2 and the nature of the polymerizable function were shown to be crucial factors in the photoinduced process. The effects of the photoinitiator concentration and light intensity were also studied. These results were explained in terms of classical kinetic models developed for all‐organic photopolymers to point out the distinctive aspects related to the use of photoinitiated polymerization in hybrid sol–gel materials. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 831–840, 2003
Batch emulsion copolymerization of 3‐O‐methacryloyl‐1,2:5,6‐di‐O‐isopropylidene‐α‐D‐glucofuranose and butyl acrylate: Synthesis and properties of the sugar latices
Authors: Koch U. , Yaacoub E.‐J.
Published: February 2003

To obtain new polymer latices based on sugar derivative, batch emulsion copolymerizations of 3‐O‐methacryloyl‐1,2:5,6‐di‐O‐isopropylidene‐α‐D‐glucofuranose (3‐MDG) and n‐butyl acrylate (BA) were carried out at 70 °C, with potassium persulfate as the initiator. 3‐MDG polymerizes faster than BA because of its higher reactivity ratio, r(3‐MDG) = 1.94 versus r(BA) = 0.54. The effect of the initial monomer composition on the polymerization rate and the thermal properties of the end copolymers was investigated. The overall rate of polymerization increases by enhancing the sugar content in the initial monomer composition. The glass‐transition temperature is linearly related to the sugar content in the copolymer. The influence of the type of surfactant showed that the particle size increases by changing from ionic to nonionic surfactant. Furthermore, the effect of the added acrylic acid (AA) on the rheological properties suggests that the sugar latices exhibit different non‐Newtonian flows depending on the pH of the latex and on the AA concentration on the particle surface. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 788–803, 2003
Samarium enolate on crosslinked polystyrene beads. II. An anionic initiator for the well‐defined synthesis of poly(allyl methacrylate) on a solid support
Authors: Tanaka Masayoshi , Sudo Atsushi , Sanda Fumio , Endo Takeshi
Published: February 2003

A samarium enolate, supported on a crosslinked polystyrene resin, successfully initiated the living anionic polymerization of allyl methacrylate (AMA) to afford the corresponding poly(AMA) with well‐controlled molecular weights. Diblock, triblock, and tetrablock copolymerizations with methyl methacrylate (MMA) were also successfully performed. The formed polymers, supported on the resin by a benzyl ester linker, were quantitatively isolated from the resin by selective cleavage of the linker with trifluoroacetic acid (TFA). Allyl ester in the side chain was not affected by this isolation step. The allyl group of the immobilized poly(AMA‐b‐MMA) on the resin was transformed into a 2,3‐dihydroxypropyl group by osmium oxidation. The resulting copolymer was isolated by TFA treatment of the resin, and it showed amphiphilicity. In both the polymerization and side‐chain modification, the formed polymers were easily washed from excess reagents only by filtration, and this demonstrated the feasibility of the automated synthesis of functional polymers based on this solid‐supported polymerization technique. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 853–860, 2003
Sterically stabilized emulsion polymerization of styrene: Pseudo‐semicontinuous approach
Authors: Capek I. , Chudej J. , Janíčková S.
Published: February 2003

The sterically stabilized emulsion polymerization of styrene initiated by a water‐soluble initiator at different temperatures has been investigated. The rate of polymerization (Rp) versus conversion curve shows the two non‐stationary‐rate intervals typical for the polymerization proceeding under non‐stationary‐state conditions. The shape of the Rp versus conversion curve results from two opposite effects—the increased number of particles and the decreased monomer concentration at reaction loci as the polymerization advances. At elevated temperatures the monomer emulsion equilibrates to a two‐phase or three‐phase system. The upper phase is transparent (monomer), and the lower one is blue colored, typical for microemulsion. After stirring such a multiphase system and initiation of polymerization, the initial coarse polymer emulsion was formed. The average size of monomer/polymer particles strongly decreased up to about 40% conversion and then leveled off. The initial large particles are assumed to be highly monomer‐swollen particles formed by the heteroagglomeration of unstable polymer particles and monomer droplets. The size of the “highly monomer” swollen particles continuously decreases with conversion, and they merge with the growing particles at about 40–50% conversion. The monomer droplets and/or large highly monomer‐swollen polymer particles also serve as a reservoir of monomer and emulsifier. The continuous release of nonionic (hydrophobic) emulsifier from the monomer phase increases the colloidal stability of primary particles and the number of polymer particles, that is, the particle nucleation is shifted to the higher conversion region. Variations of the square and cube of the mean droplet radius with aging time indicate that neither the coalescence nor the Ostwald ripening is the main driving force for the droplet instability. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 804–820, 2003
Photosensitive fluorinated polyimides with a low dielectric constant based on reaction development patterning
Authors: Miyagawa Tomoko , Fukushima Takafumi , Oyama Toshiyuki , Iijima Takao , Tomoi Masao
Published: February 2003

The fluorinated polyimide PI(6FDA/HFBAPP) was prepared by the reaction of 4,4′‐(hexafluoroisopropylidene)diphthalic anhydride (6FDA) with 2,2‐bis[4‐(4‐aminophenoxy)phenyl]hexafluoropropane (HFBAPP) in 1‐methyl‐2‐pyrrolidone/toluene. A multiblock copolyimide with both fluorinated and rigid‐rod segments, PI(6FDA/HFBAPP)(BPDA/2‐DMB), was prepared by the addition of a second dianhydride, 3,3′,4,4′‐biphenyltetracarboxylic dianhydride (BPDA), and a second diamine, 2,2′‐dimethylbenzidine (2‐DMB), to the polyimide main chain. The potential lithographic performance of photosensitive polyimides composed of nonphotosensitive fluorine‐containing polyimides and photosensitive diazonaphthoquinone (DNQ) was studied on the basis of a new imaging principle recently proposed by our laboratory, that is, reaction development patterning. Neat PI(6FDA/HFBAPP) showed a low dielectric constant (ϵ) of 2.41 and a low dissipation factor (tan δ) of 0.0027 at 20 GHz, and a 10‐μm resolution of the fluorinated polyimide/DNQ system was demonstrated with reactive development with a solution including ethanolamine after ultraviolet exposure. Although slight changes in the dielectric properties were observed in the presence of DNQ residues, these values (ϵ = 2.63 and tan δ = 0.0033 at 20 GHz) were low enough for use in microelectronic applications. However, PI(6FDA/HFBAPP)(BPDA/2‐DMB), having a lower coefficient of thermal expansion (CTE; 33 ppm/°C) than PI(6FDA/HFBAPP) (49 ppm/°C), exhibited good positive photosensitivity, whereas the relatively low‐CTE multiblock copolyimide displayed a much higher ϵ value (3.48 at 1 MHz) than the highly fluorinated polyimide (2.88 at 1 MHz). A film consisting of PI(6FDA/HFBAPP)(BPDA/2‐DMB) and the remaining DNQ derivatives showed a CTE value comparable to that of the neat polyimide film. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 861–871, 2003
Solution polycondensation of isophthalic acid/terephthalic acid and tetrachlorobisphenol A of low polymerizability with tosyl chloride/dimethylformamide/pyridine improved by the introduction of comonomers of smaller sizes
Authors: Higashi Fukuji , Moriya Miwako
Published: February 2003

The copolycondensations of a mixture of equal parts of isophthalic acid and terephthalic acid with tetrachlorobisphenol A (TC‐BPA) and various aromatic diol comonomers were performed with a tosyl chloride/dimethylformamide/pyridine condensing agent. The reaction with bisphenols containing nonpolar substituents yielded better results than the reaction with polar groups did. Dihydroxybenzenes smaller in size than bisphenols of two benzene rings, especially chlorohydroquinone and chlororesorcinol, were satisfactorily incorporated and yielded copolymers of high inherent viscosities and weight‐average molecular weights (by gel permeation chromatography). The results of the copolycondensations were examined with sequence distributions in the resultant copolymers by NMR and were well evaluated by the ratio of the length of comonomer unit segments to TC‐BPA unit segments. Homopolycondensation with TC‐BPA in the presence of dichlorobenzenes as additives was also promoted to some extent. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 821–830, 2003
Novel functional polymers: Poly(dimethyl siloxane)–polyamide multiblock copolymers. XI. The effects of sequence regularity on the thermal and mechanical properties
Authors: Kang Eui‐Chul , Kaneko Tatsuo , Shiino Daijiro , Akashi Mitsuru
Published: February 2003

Poly(aramid silicone) (PAS) multiblock copolymers were synthesized by the low‐temperature solution polycondensation of isophthaloyl dichloride (IPC) and two diamines, diamino poly(dimethyl siloxane) (PDMS; number‐average molecular weight = 1680) and 3,4′‐diaminodiphenylether (3,4′‐DAPE), in tetrahydrofuran/dimethylacetamide (2/1 v/v). Two synthetic methods for the control of the PAS sequence were used: a one‐step synthesis that presumably gave PAS with a random sequence and the polymerization of 3,4′‐DAPE with a presynthesized dimer, IPC–PDMS–IPC (two‐step synthesis), that presumably gave PAS with an alternating sequence of 3,4′‐DAPE and PDMS segments. In a 1H NMR study of the amide protons of the 3,4′‐DAPE component in PAS, the relative length of the 3,4′‐DAPE segment of randomly sequenced PAS to that of ideally sequenced PAS could be estimated. The glass‐transition temperatures of the 3,4′‐DAPE and PDMS segments of random PAS were 152–234 and −104 to −117 °C, respectively, whereas the alternating PAS sequences showed no glass transition for the 3,4′‐DAPE segments. A tensile test indicated that randomly sequenced PAS behaved like a rubber‐toughened material at lower PDMS contents and like a thermoplastic elastomer at higher PDMS contents, whereas the alternately sequenced PAS behaved like a very soft rubber, showing a high value of elongation at the breaking point. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 841–852, 2003
Negative expiratory pressure: A new tool for evaluating lung function in children?
Authors: Tauber Erich , Fazekas Tamas , Eichler Irmgard , Eichstill Christina , Gartner Christian , Koller Dieter Y. , Frischer Thomas
Published: February 2003

The negative expiratory pressure technique (NEP) has been applied in adults with chronic obstructive pulmonary disease (COPD), demonstrating flow limitation in many of these patients. Because this technique does not require patient cooperation, it is of potential interest for application in the pediatric population. This study was performed to test the feasibility of NEP in children, and to further investigate it in children with asthma and cystic fibrosis (CF). We performed NEP (0.3–0.7 kPa) measurements in 14 healthy children (13.3 years, ± 2.4), in 12 children with asthma (11.7 years, ± 3.0), and in 17 children with CF (13.3 years, ± 2.7). NEP‐derived flow‐volume loops were visually analyzed for flow limitation at tidal breathing. In addition, expiratory flow at 50% of tidal volume (TEF50) was measured. In healthy children, the intraclass coefficient of correlation was 77%, and intraindividual short‐ and long‐term variability was 5.8% and 10.8%, respectively. In asthmatics, TEF50 was lower compared with controls, and increased after inhalation of salbutamol. However, appropriate size‐correction has still to be established. Measurement of TEF50 using NEP is feasible in children. Despite good reproducibility in individual patients, the high intersubject variability may limit its usefulness as a clinical tool. In addition, the lack of flow limitation using NEP even in severely obstructed patients with CF warrants further investigation. Pediatr Pulmonol. 2003; 35:162–168. © 2003 Wiley‐Liss, Inc.
Influence of particle size on lung deposition and pharmacokinetics of beclomethasone dipropionate in children
Authors: Agertoft L. , Laulund L.W. , Harrison L.I. , Pedersen S.
Published: February 2003

We set out to evaluate lung deposition, systemic availability, and basic pharmacokinetic parameters of beclomethasone dipropionate (BDP) in children with chronic asthma. Plasma levels of BDP, 17 and 21 beclomethasone monopropionate (17‐BMP and 21‐BMP), and beclomethasone were measured after an intravenous infusion of 60 μg BDP and after inhalation of A) 100 μg HFA‐BDP, B) 200 μg HFA‐BDP, C) 200 μg HFA‐BDP after ingestion of charcoal to block gastrointestinal (GI) absorption of drug, and D) 400 μg CFC‐BDP. A breath‐actuated pMDI (Autohaler™) was used for HFA inhalations, and a pMDI with a large volume spacer (Volumatic™) for CFC inhalations. Treatments A–D were given in a randomized, cross‐over design. Fourteen patients aged 10–14 years completed all 5 study days. The mean systemic bioavailabilities in percent of dose leaving the canister valve (ex‐valve) were 70% (100 HFA), 74% (200 HFA), 60% (200 HFA + charcoal), and 27% (400 μg CFC). After HFA treatment, 82% of the systemically available dose was absorbed through the lungs, and 18% from the gastrointestinal tract. The estimated bioavailability of BDP from the GI tract was 68%. BDP was metabolized to 17‐BMP within minutes. Mean steady‐state volume of distribution of 17‐BMP was 84 L, and the mean terminal half‐life (T½) after the four inhalations was 2.7 hr (range, 2.2–3.7 hr). Mean T½ and clearance after i.v. administration were 1.7 hr and 0.9 L/min, respectively. The HFA Autohaler delivers approximately three times as much BDP to the intrapulmonary airways as a CFC‐pMDI with a large volume spacer. Pediatr Pulmonol. 2003; 35:192–199. © 2003 Wiley‐Liss, Inc.
Airway and tissue mechanics in anesthetized paralyzed children
Authors: Peták Ferenc , Babik Barna , Asztalos Tibor , Hall Graham L. , Deák Zoltán I. , Sly Peter D. , Hantos Zoltán
Published: February 2003

To estimate the mechanical properties of the airways and respiratory tissues, respiratory system impedance (Zrs) was measured with low‐frequency forced oscillations in 26 anesthetized, paralyzed children (aged 3 months–10 years) undergoing surgical correction of congenital heart diseases. Zrs was determined from the signals of tracheal flow and pressure between 0.4–12 Hz before surgery at zero mean transrespiratory pressure. The pulmonary (ZL) and chest wall (ZW) components of Zrs were also determined in 5 children by measuring esophageal pressure. A model containing frequency‐independent resistance (R) and inertance (I), and coefficients of tissue‐damping (G) and elastance (H), was fitted to the Zrs, ZL, and ZW spectra. The total respiratory parameters normalized to body weights were 82.2 ± 8.5 (SE) hPa · sec · l−1 · kg, 0.152 ± 0.05 hPa · sec2 · l−1 · kg, 293.8 ± 20.0 hPa · l−1 · kg, and 1,583 ± 65.5 hPa · l−1 · kg, for R, I, G, and H, respectively. The measurements of ZL and ZW revealed the dominance of the lungs in R (91 ± 4.3%) and I (109 ± 16%), and the major contribution of the lung parenchyma to G (61 ± 7.3%) and H (66 ± 7.4%) of the total respiratory system. It is concluded that anesthesia‐paralysis provides an ideal condition for the measurement of low‐frequency forced oscillatory impedance and its partitioning into airway and tissue components in mechanically ventilated children. The separation of pulmonary and chest wall mechanics demonstrates that airway properties can be estimated appropriately from Zrs data, while the chest wall may damp the changes in parenchymal properties. Pediatr Pulmonol. 2003; 35:169–176. ©2003 Wiley‐Liss, Inc.
Case of congenital bronchial atresia detected by fetal ultrasound
Authors: Kamata Shinkichi , Sawai Toshio , Usui Noriaki , Nose Keisuke , Kitayama Yasuhiro , Iiboshi Yasuhiko , Okada Akira , Kanzaki Tohru
Published: February 2003

Congenital bronchial atresia is an anomaly characterized by a mucocele associated with a blindly terminating segmental or lobar bronchus. We report on a case of congenital atresia of the left superior segmental bronchus (B6) followed by fetal ultrasonography, which showed a large simple cyst with a surrounding small echogenic area. A large cyst and persistent lung fluid in the affected segment were noted in the early neonatal period. Pediatr Pulmonol. 2003; 35:227–229. © 2003 Wiley‐Liss, Inc.
Determining the amount of Si–Si bonding in CVD oxynitrides
Authors: Tompkins Harland G. , Smith Steven , Convey Diana , Gregory R. B. , Kottke M. L. , Collins David
Published: January 2003

In this work we propose a method of determining the amount of excess Si in chemical vapor deposited (CVD) oxynitrides that is due to silicon bonded to other silicon (the amount of excess Si due to more‐than‐normal Si–H bonds can be determined by Fourier transform infrared spectroscopy and has been dealt with adequately in the literature). The amount of Si–Si bonding in CVD oxynitride usually represents a small fraction of the total silicon (<5%) and we show that, in this case, the subtractive method of determination is inadequate due to the uncertainty in the values obtained from typical elemental analysis (with Rutherford backscattering spectroscopy or other methods). By choosing atypical samples made specifically such that the amount of Si–Si bonding represents a significant fraction of the total silicon (mostly >50%), we use the subtractive method to provide a relationship between the extinction coefficient k at a particular wavelength (250 nm) that can be used for typical samples. Copyright © 2003 John Wiley & Sons, Ltd.
Electropolishing of aluminium: processing and assessment of visual appearance
Authors: Van Gils S. , Holten S. , Stijns E. , Vancaldenhoven M. , Terryn H. , Mattsson L.
Published: January 2003

The process of electropolishing aluminium and its influence on the visual appearance are studied. Angle‐resolved scattering (ARS) and total integrated scattering (TIS) are used to investigate the influence of electropolishing on surface roughness. The ARS apparatus is built similar to the ASTM E430‐97A standard. This standard test method is used for measurement of distinctness of image and haze by goniophotometry. These visual appearance parameters, together with TIS, reflect the changes in surface roughness. Total reflectance is correlated to the composition of the aluminium as well as the composition and thickness of the layer formed on the aluminium. Copyright © 2003 John Wiley & Sons, Ltd.
AFM analysis of organic silane thin films for bioMEMS applications
Authors: Popat Ketul C. , Sharma Sadhana , Johnson Robert W. , Desai Tejal A.
Published: January 2003

Designing surfaces that elicit the desirable response is essential for bioMEMS (biological microelectromechanical systems) applications. To this end, we have developed two different types of silane film—hydrophobic and hydrophilic—using vinyltrichlorosilane and poly(ethylene glycol) silane, respectively. As the surface topography plays a very important role in governing protein or cell interactions, these films were characterized extensively using atomic force microscopy. All the films developed were found to have a very low root‐mean‐square roughness value (<1.3 nm). Furthermore, the topography of protein‐adsorbed silane‐modified surfaces was investigated because cell adhesion is mediated primarily by proteins. Three‐dimensional and section plots were able to differentiate the way in which protein interacts with hydrophobic and hydrophilic surfaces. Copyright © 2003 John Wiley & Sons, Ltd.
Surface characterization of Co,K/La2O3 catalysts used for the catalytic combustion of diesel soot
Authors: Moggia J. M. , Milt V. G. , Ulla M. A. , Cornaglia L. M.
Published: January 2003

Catalysts of Co,K/La2O3 have been prepared by wet impregnation. The samples have been calcined at 400°C and 700°C and have been characterized for phase composition using x‐ray diffraction and Fourier transform infrared spectroscopy. The XPS analysis of the samples has been obtained by examination of the O 1s, K 2p, C 1s and La 3d spectral regions. The XPS data are discussed with respect to the calcination temperatures and the soot combustion performed in the spectrometer reaction chamber. Analysis of the XPS data indicates considerable carbonation of the surfaces of all samples, even after burning the soot. The K/La2O3 solid presents the highest content of surface carbonated species, showing the highest catalytic activity for soot combustion. Interaction of the catalysts with CO2 is studied by temperature‐programmed desorption and microbalance experiments. Kinetic studies and surface characterization of the potassium‐containing samples suggest that an appropriate surface potassium concentration is necessary for a synergetic action between potassium and lanthanum. In the cobalt‐containing catalysts calcined at 700°C, an increase is observed in the concentration of the outer‐layer perovskite species when the potassium content increases, following the same tendency observed in the bulk. Such LaCoO3 species would limit the reaction of lanthanum with CO2. Copyright © 2003 John Wiley & Sons, Ltd.
Studies on the repassivation behavior of aluminum and aluminum alloy exposed to chromate solutions
Authors: Chidambaram Devicharan , Jaime Vasquez M. , Halada Gary P. , Clayton Clive R.
Published: January 2003

This study explores the repassivation ability of a scratch in a chromate conversion coating (CCC) on aluminum alloy, AA2024‐T3, and hence evaluates the theory of migration of hexavalent chromium ions from the protected surface of the aluminum alloy to the exposed surface. To confirm that protection was indeed restored by hexavalent chromium ions, the repassivation of a scratch on pure aluminum exposed to a dichromate solution was studied. This forms the simplest subsystem model of the CCC on the alloy in which the CCC is replaced by pure hexavalent chromium and alloy with pure aluminum. Open‐circuit potential measurements, synchrotron infrared microspectroscopy (SIRMS) and secondary ion mass spectroscopy (SIMS) have been used judiciously to evaluate the repassivation behavior. Results indicate that the dichromate ions have high mobility. The slow migration of Cr(VI) ions from the protected surface to the scratch is observed to result in repassivation, as seen from the steady increase in the potential in 0.05 M NaCl solution. The results obtained from SIMS and SIRMS confirm the migration of the oxyanions from the protected region to the metal surface exposed by the scratch. The SIRMS results indicate the formation of an Al(III)–Cr(VI) complex, proposed and shown to be formed in the pits. Copyright © 2003 John Wiley & Sons, Ltd.
Auger peak shape analysis of AlN film grown by ammonia plasma
Authors: Wang P. W. , Sui Shixian , Durrer W. G. , Craig J. H.
Published: January 2003

An AlN film was grown using ammonia plasma and characterized with Auger electron spectroscopy in depth profile mode using argon sputtering. After growth of AlN on a 6061 Al substrate in a plasma chamber, the sample was removed from the vacuum and transported to an ultrahigh vacuum surface analysis system. Detailed AES spectra of Al, O and N are presented as a function of sputtering time (depth). Relative concentration changes were observed for the KLL O and KLL N signals but there were no significant lineshape changes, however significant relative concentration and lineshape changes associated with the LVV Al signal were observed. Lineshape analysis indicates the presence of the following bonds: Al–O (56 eV), Al–N (59 eV) and Al–Al (68 eV). Copyright © 2003 John Wiley & Sons, Ltd.
Surface characterization of keratin fibres treated by water vapour plasma
Authors: Molina R. , Jovančić P. , Jocić D. , Bertran E. , Erra P.
Published: January 2003

The effect of water vapour plasma treatment on the shrinkage behaviour and chemical properties of the surface of keratin fibres was studied. The wettability and shrink resistance of wool were improved even at low plasma treatment times. The values of the advancing contact angles of keratin fibres treated with plasma provide evidence of the formation of hydrophilic groups in the wool surface. Analysis by XPS reveals that oxidation of the fatty acid monolayer (F‐layer) prevails over its removal in the early stages of plasma treatment. The increase in treatment time results in a progressive removal of the F‐layer. Copyright © 2003 John Wiley & Sons, Ltd.
Consequences of x‐ray absorption fine structure for quantitative core‐level photoelectron spectroscopy
Authors: Karolewski M. A.
Published: January 2003

The dependence of x‐ray absorption fine structure (XAFS) on the chemical environment implies a corresponding environmental dependence of photoionization cross‐sections. The practical consequences of the XAFS for quantitative core‐level photoelectron spectroscopy have been studied for a number of materials with the help of simulations based on the ab initio FEFF code. The XAFS effects are predicted to be significant only for photoelectron kinetic energies below 250–300 eV. These effects take the form of systematic sensitivity factor variations between different chemical structural environments (e.g. compound materials quantified with reference to elemental standards). Apart from a few exceptions (e.g. the 2p core levels of Zn, Ga, Ge and As in metallic environments), the XAFS should introduce no significant errors when conventional Mg Kα or Al Kα sources are used for excitation. For core‐level spectra excited with synchrotron radiation or He II radiation sources, the quantification errors can readily approach or exceed 10% at room temperature (and are expected to increase at lower temperatures). Copyright © 2003 John Wiley & Sons, Ltd.
Influence of target surface degradation on the properties of r.f. magnetron‐sputtered calcium phosphate coatings
Authors: Boyd A. , Akay M. , Meenan B. J.
Published: January 2003

This paper reports a detailed study of how repeated r.f. magnetron sputtering from a hydroxyapatite (HA) powder target affects the nature and reproducibility of a sequential series of thin‐film coatings deposited onto Ti6Al4V substrates. An evaluation of the effective lifespan of the HA sputter targets and the reproducibility of the calcium phosphate (CaP) coatings produced from them has been made from Fourier transform infrared spectroscopy, XPS and, as appropriate, atomic force microscopy and SEM/energy dispersive x‐ray analyses. The annulus region of the target surface, from which sputtering under r.f. magnetron conditions normally occurs, showed severe surface degradation after only one deposition run, as indicated by significant PO43− and OH− depletion. This deterioration continued after each subsequent deposition cycle but to a much lesser extent than that observed in the initial sputtering period.

The layers produced from all of the sputter runs contained the expected Ca2+ and PO43− species characteristic of a CaP system but were OH− deficient in the as‐deposited state. However, the chemical and morphological properties of the coatings did not change significantly until after the third consecutive sputter cycle. Hence, these data indicate that, even though a significant level of degradation of the HA target occurs at the outset of the sputtering procedure, the general plasma conditions employed here have a dominant influence on the coating properties until a critical degradation condition is met. As such, the compacted HA powder targets of interest can have a life‐cycle greater than single usage without detriment to the chemistry and morphology of the coatings produced from them. Copyright © 2003 John Wiley & Sons, Ltd.
Pump–probe second harmonic generation study of ultrafast spin dynamics in semiconductor multilayers
Authors: Glinka Yu. D. , Shahbazyan T. V. , Perakis I. E. , Tolk N. H. , Liu X. , Sasaki Y. , Furdyna J. K.
Published: January 2003

We report the first application of pump–probe second harmonic generation (SHG) measurements to characterize optically induced magnetization in non‐magnetic multilayer semiconductors. In the experiment, spin‐polarized electrons are excited selectively by a pump beam in the GaAs layer of GaAs/GaSb/InAs structures. However, the resulting net magnetization manifests itself through the induced SHG probe signal from the GaSb/InAs interface, thus indicating a spin‐polarized electron transport across the heterostructure. We find that the magnetization dynamics are governed by an interplay between the spin density evolution at the interfaces and the spin relaxation. Copyright © 2003 John Wiley & Sons, Ltd.
Biomimetic materials with tailored surface micro‐architecture for prevention of marine biofouling
Authors: Jelvestam Maria , Edrud Susanna , Petronis Sarunas , Gatenholm Paul
Published: January 2003

The long‐term goal of this study has been to prepare materials with a designed surface micro‐architecture that is able to prevent marine fouling by barnacles. Rows of steep microstructures with an elevation of a few micrometres separated from each other by 60 µm were manufactured using a biomimetic approach based on crystallization of calcite on surfaces of chemically patterned templates with carboxylate functionality. Templates were produced by the microcontact printing process using microfabricated silicone stamps with a surface micro‐architecture that has been shown to prevent barnacle settling. Electron spectroscopy for chemical analysis (ESCA), secondary ion mass spectrometry (SIMS) imaging and observations of wetting behaviour were used to examine the surfaces. The templates were used to grow surface microstructures by controlled crystallization of calcium carbonate by immersion in calcium chloride solution. Crystals grow randomly on the acidic areas of surfaces with 60/40 µm lines, whereas they grow in a regular fashion on a surface stamped with tiny (3–6 µm) 16‐mercaptohexadecanoic acid lines. This study showed that it is possible to prepare stable surface microstructures of a size up to 50 µm in a regular arrangement of lines. Copyright © 2003 John Wiley & Sons, Ltd.
Analysis of the surface chemistry of oxidized polyethylene: comparison of XPS and ToF‐SIMS
Authors: Briggs D. , Brewis D. M. , Dahm R. H. , Fletcher I. W.
Published: January 2003

A series of low‐density polyethylene (LDPE) surfaces, chemically modified using a number of oxidative techniques employed for adhesion enhancement (pretreatments), have been studied by time‐of‐flight (ToF) SIMS and XPS. The methods consisted of corona discharge, flame, electrochemical, chromic acid, acid dichromate and acid permanganate treatment. All except flame treatment were performed under mild and fairly severe conditions to yield a range of surface chemistries. The XPS analysis, using high energy resolution and a refined approach to C 1s curve‐fitting, provided some new insights into the quantitative assessment of the type and concentration of functional groups. Both positive and negative ion ToF‐SIMS spectra were obtained at high mass resolution. The oxygen‐containing fragments were identified by accurate mass analysis and subjected to a detailed comparison with the XPS results. No convincing relative intensity correlations could be identified that would allow particular secondary ion fragments to be associated strongly with particular functional groups (in this multi‐functional surface situation). Inorganic residues resulting from wet chemical treatments were also investigated and here the two techniques were found to be more complementary. Copyright © 2003 John Wiley & Sons, Ltd.
Ultrathin cobalt silicide film formation on Si(100)
Authors: Hwang I. Y. , Kim J. H. , Oh S. K. , Kang H. J. , Lee Y. S.
Published: January 2003

The interfacial reaction between ultrathin Co film and substrate Si(100) was studied by in situ XPS using monochromatized Al Kα. When the Co is deposited on Si(100) at room temperature, CoSi2 is formed during the initial stage of Co deposition and then metallic Co starts to grow sequentially. For 8 ML Co deposition on Si(100) the interfacial reaction layer is relatively thin compared with the pure Co overlayer, which is not involved in the interfacial reaction in depth. The Co layers change rapidly to CoSi layers after annealing at 270°C, and then CoSi2 layers form after annealing at 540°C for 2 min. The CoSi2 layers are changed to CoSi2 islands by post‐annealing at >650°C. Copyright © 2003 John Wiley & Sons, Ltd.
Enhancement of polymer hydrophobicity by SF6 plasma treatment and argon plasma immersion ion implantation
Authors: Rangel E. C. , Bento W. C. A. , Kayama M. E. , Schreiner W. H. , Cruz N. C.
Published: January 2003

In this study sulphur hexafluoride (SF6) plasmas and argon plasma immersion ion implantation (ArPIII) techniques have been applied to improve the hydrophobicity of poly(tetrafluoroethylene) (PTFE), polyurethane and silicone surfaces. As evaluated by water contact angle measurements, all the treatments resulted in a significant enhancement in the hydrophobicity of the polymers. However, exposure of the treated samples to air induced a strong variation in their hydrophobicity as a consequence of post‐plasma reactions between atmospheric species and remnant surface free radicals. X‐ray photoelectron spectroscopy results strongly suggest that for polyurethane and silicone the surface fluorination by SF6 plasmas and the creation of new carbon bonds and radicals are the main agents for hydrophobicity enhancement. The PTFE exposed to ArPIII revealed increases in the contact angles after exposure to air. A significant incorporation of oxygen and the formation of new carbon bonds were revealed by XPS measurements. Copyright © 2003 John Wiley & Sons, Ltd.