Effect of the surface modification of the synthetic meshes used in the surgical treatment of pelvic organ prolapse on the tissue adhesion and clinical functionality

Stress urinary incontinence and pelvic organ prolapse represent important conditions affecting adult women’s health. Lately, the properties and performance of the polymer materials used in the treatment of pelvic organ prolapse have been improved by modulating from their formula. Materials investigated in our study are polypropylene meshes used by clinicians in surgical treatment of urinary incontinence and utero-vaginal prolapse. In order to make a comparative analysis, we confronted the structure and surface morphology of native synthetic polypropylene meshes with explanted fragments from the same mesh type after clinical use. FTIR investigations revealed little change in structure after implantation, somehow insignificant. Scanning electron microscopy (SEM) demonstrates modification in surface morphology even just by passing through the transobturator passage, whereas after implantation the surface deteriorates. SEM on explanted meshes proves the encapsulation process of the mesh to be more similar to a foreign body reaction rather than to the adhesion and integration of the synthetic mesh into the organism. Histological analysis of the surrounding tissues near explanted mesh was made in some relevant clinical cases, because the tissue response is an important factor in order to evaluate the tissue adhesion at the polypropylene mesh surface. Based on our experiments and clinical experience we’ve designed an adhesion score. It applies to meshes used in pelvic organ prolapse surgery measuring the following important factors: tenacity, extent of adhesion, macroscopic and microscopic aspects and ease of dissection from surrounding tissues.     

Epoxysilane as adhesion promoter in duplex system

Coatings are one of the most used protection methods for metals. Metallic coatings, such as zinc and its alloys, are used to protect steel in mild corrosive environments. In aggressive environments, on the other hand, organic coatings must be employed in the so-called duplex systems. However, the galvanized steel/organic coating adhesion is a problem and many attempts had been done to solve it with the incorporation of a chromate-based or phosphate-based interlayer. Nowadays, the use of these compounds is questioned due to their environmental impact and new adhesion promoters, like silanes, are being investigated. The aim of this paper was to study the adhesion and the anticorrosive behavior of a duplex system with a layer of glycidoxypropyltrimethoxysilane (γ-GPS) between the zinc and the coating. Polarization tests and corrosion potential measurements were done on the γ-GPS/galvanized steel to select the better anticorrosive pretreatment conditions for the application of an organic traditional paint. Dried and wet adhesion of the coating to the pretreated substrate was studied by the standard tape test. Salt spray test and electrochemical noise technique were employed to study the corrosion behavior of the duplex systems. Results showed that the films of γ-GPS formed on galvanized steel diminished the corrosion current of the metal, but they do not protect the substrate by a barrier effect. The incorporation of the pretreatment in the duplex system increased the adhesion of the paint, especially when the pretreated substrate was cured 1?h at 200?°C.     

Solid-phase electrochemical reduction of graphene oxide films in alkaline solution

Graphene oxide (GO) film was evaporated onto graphite and used as an electrode to produce electrochemically reduced graphene oxide (ERGO) films by electrochemical reduction in 6 M KOH solution through voltammetric cycling. Fourier transformed infrared and Raman spectroscopy confirmed the presence of ERGO. Electrochemical impedance spectroscopy characterization of ERGO and GO films in ferrocyanide/ferricyanide redox couple with 0.1 M KCl supporting electrolyte gave results that are in accordance with previous reports. Based on the EIS results, ERGO shows higher capacitance and lower charge transfer resistance compared to GO.     

Emulsion copolymerization of vinyl acetate-ethylene in high pressure reactor-characterization by inline FTIR spectroscopy

The objective of this research was to investigate the effect of temperature, pressure, initiator concentration and agitation rate, in ethylene-vinyl acetate emulsion copolymerization, on copolymer composition. The inline React-IR ATR system was used to monitor the reaction as well as to determine residual free vinyl acetate. Pressure, temperature and agitation rate have great influence on mass transfer of ethylene monomer to the reaction sites. The vinyl acetate was introduced in semi-batch mode as well as ethylene since the copolymerization was carried out under a constant pressure of ethylene. The higher temperature results in lower content of ethylene incorporated in copolymer. Increase of pressure has a direct effect on the ethylene content in the copolymers through increasing solubilization of ethylene monomer which in turn increases ethylene content in the copolymers. Copolymers of up to 15 wt.% of ethylene content have been synthesized at an ethylene pressure of 30 bar and a temperature of 75 °C. Analytical methods, such as differential scanning calorimetry, nuclear magnetic resonance, thermogravimetric analysis, and infrared spectroscopy were used for characterization of copolymers.     

Surface modification of bioceramics by grafting of tailored allyl phosphonic acid

Abstract

A new route to interfacial bonding between ceramic and matrix in biocomposites is identified. A tailored allyl phosphonic acid is used as a coupling agent bound to the surface of a bioceramic to form a 'grafted' calcium phosphate (CAP). The allyl phosphonic acid coupling agent is synthesised by reaction of allyl halide and trialkyl phosphite. Successful synthesis was confirmed by nuclear magnetic resonance and Fourier transform infrared spectroscopy (FTIR). The allyl phosphonic acid was incorporated onto calcium phosphate using a wet chemical coprecipitation synthesis route. The resulting 'grafted' CAP was characterised using FTIR coupled with photoacoustic sampling, and Fourier transform Raman spectroscopy (FTR). The spectroscopic data suggest an interaction between the allyl phosphonic acid and calcium phosphate resulting from observed reductions in intensity of the hydroxyl (3570 cm^?1) and phosphate ν ₃ (1030 cm^?1) peaks. The continued presence of C=C functionality on the surface of the grafted CAP was indicated by FTIR and FTR spectra (peaks at 1650 and 1635 cm^?1 respectively) and confirmed by X-ray photoelectron spectroscopy (XPS). On the basis of these results, it is concluded that grafted CAP may be used to produce a chemically bonded composite with superior mechanical properties.     

采用DSC和FTIR对木材和API胶粘剂间反应的研究

采用差示扫描星热法(Differential Scanning Calormelry,简称DSC)和傅立叶变换红外吸收光谱(Fourier Transform Infrared Spectroscopy,简称FTIR)对木材和水性高分子异氰酸酯胶粘剂(Aqueous Polymer Isocyanate,简称API)的胶接机理进行了研究。DSC和FTIR的试验结果均表明:API胶粘剂和木材间发生了化学反应:API胶粘剂和木材间发生的反应所需活化能远小于API胶粘剂的主剂+固化剂的活化能,亦即用API 胶粘剂胶接木材时发生的反应要比API胶粘剂本身的固化反应容易得多,同时从理论上证明使用API胶粘剂胶接木材时装配时间最长不应超过其活性期的一半时间,且装配时间越短越好;文中还研究了升温速率对API胶粘剂DSC图谱的影响。     

Fourier transform Raman and Fourier transform infrared spectroscopy studies of silk fibroin

The chemical and conformational structures of Bombyx mori silk were studied with the complementary techniques of Fourier transform Raman spectroscopy and Fourier transform infrared spectroscopy. The Fourier transform Raman spectrum of silk showed strong bands for the photosensitive aromatic amino acids tyrosine, tryptophan, and phenylalanine. Intensive UV/ozone irradiation reduced the Raman intensities of the amide III band and the tyrosine signals due to peptide chain scission of the silk polymer and the photochemical changes in the tyrosine residues on the silk molecules. However, the Raman spectroscopy changes for tryptophan were less clearly defined because of peak overlapping with other amino acid signals and the low concentration of tryptophan. The Fourier transform infrared (attenuated total reflectance) technique, coupled with second‐derivative spectroscopy analysis, demonstrated a decrease in the crystallinity degree and tyrosine content of UV/ozone‐irradiated silk, as indicated by changes in the Fourier transform infrared bands of amide III doublet and tyrosine signals. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 1999–2004, 2005     

Adsorption and surface reactions of acetaldehyde on alumina-supported noble metal catalysts

Adsorption and further surface transformations of acetaldehyde on Al₂O₃-supported noble metal catalysts were studied by FTIR spectroscopy. Two forms (H-bridge bonded and bonded to Lewis sites) of molecularly adsorbed acetaldehyde were detected. -aldolization of acetaldehyde into crotonaldehyde was observed already at 300 K on all surfaces investigated. The formation of adsorbed crotonaldehyde depended on the temperature and on the nature of the metal. The gas phase products (crotonaldehyde, benzene, hydrogen, ethane, ethylene and acetylene) were analyzed by mass spectrometer. Their appearance in the gas phase and their amounts depended on the nature of the metal and on the temperature.To whom correspondence should be addressed. E-mail: jkiss@chem.u-szeged.hu     

Sulfur‐free lignin as reinforcing component of styrene–butadiene rubber

The potential application of lignin biopolymer as a component of styrene–butadiene rubber was examined with regard to its ability to reinforce the vulcanizates. It was shown that the sulfur‐free lignin preparation improved physicomechanical properties of rubber. The determination of the coefficient of lignin activity confirmed that lignin acts as an active filler. FTIR characteristics of lignin isolated from the vulcanizate containing 20 phr lignin indicated its interaction with the sulfur system, resulting in formation of noncyclic sulfide structures. In the case of higher lignin amount in the vulcanizate, some interfacial interaction between lignin and SBR may occur. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 924–929, 2005     

Polyaniline‐supported acid catalyst: Esterification of cinnamic acid with alcohols

Polyaniline‐supported acid salts such as polyaniline‐hydrochloride, polyaniline‐sulfate, and polyaniline‐nitrate were prepared by oxidation of aniline using benzoyl peroxide and ammonium persulfate as oxidizing agents. Polyaniline salts were used as catalysts in the esterification of cinnamic acid with alcohols. Polyaniline‐sulfate salt was found to be the best catalyst for the esterification of cinnamic acid. The reusability, handling, and recovery of the catalyst were found to be good. The yield of the ester depended on the type of the polyaniline salt, amount of the catalyst, amount of alcohol, and both the time and the temperature of the reaction. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 1584–1590, 2005