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PubMed2006

Adsorption of human salivary mucin MG1 onto glow-discharge plasma treated acrylic resin surfaces.

It has been suggested that altering the surface properties of acrylic resin material may change the nature of the adsorbed pellicle affecting denture retention and microbial adherence. This study aimed at evaluating the adsorption of salivary high molecular-weight mucins, a major component of denture pellicle, onto modified acrylic resin surfaces. (Poly) methylmethacrylate specimens were treated by glow discharge plasma technique, using hydrophilic 2-Hydroxyethylmethacrylate monomer or oxygen (O(2)) gas and hydrophobic Hexamethyldisiloxane monomer, at different discharge powers. Acrylic samples were incubated with high-molecular weight mucin, MG1 purified from saliva, the adsorbed fractions were transferred to nitrocellulose membranes by slot-blot technique, stained by periodic acid-Schiff and colour intensities were analysed by a colour densitometer. Higher amounts of mucins were adsorbed on all the surfaces modified by glow-discharge plasma treatment. Within the limitations of this study, it was concluded that glow-discharge plasma altered the surfaces of acrylic resin denture base materials and significantly increased the adsorption of high molecular-weight mucins at varying levels depending on plasma parameters.

Adsorption↗
PubMed2006

Contact allergy to (meth)acrylates in the dental series in southern Sweden: simultaneous positive patch test reaction patterns and possible screening allergens.

Contact allergy to dental allergens is a well-studied subject, more so among dental professionals than dental patients. 1632 subjects had been patch tested to either the dental patient series or dental personnel series at the department of Occupational and Environmental Dermatology, Malmö, Sweden. Positive patch tests to (meth)acrylate allergens were seen in 2.3% (30/1322) of the dental patients and 5.8% (18/310) of the dental personnel. The most common allergen for both groups was 2-hydroxyethyl methacrylate (2-HEMA), followed by ethyleneglycol dimethacrylate (EGDMA), triethyleneglycol dimethacrylate, and methyl methacrylate. 47 (29 dental patients and 18 dental personnel) out of these 48 had positive patch tests to 2-HEMA. All 30 subjects who had a positive reaction to EGDMA had a simultaneous positive reaction to 2-HEMA. One dental patient reacted only to 2,2-bis[4-(2-hydroxy-3-methacryloxypropoxy) phenyl]propane (bis-GMA). From our data, screening for (meth)acrylate contact allergy with 2-HEMA alone would have picked up 96.7% (29/30) of our (meth)acrylate-allergic dental patients and 100% (18/18) of our (meth)acrylate-allergic dental personnel. The addition of bis-GMA in dental patients would increase the pick-up rate to 100%.

Allergens↗
PubMed2002

Thermophysical properties of fluorinated acrylate homopolymers: mixing and phase separation.

The thermophysical properties of fluorinated acrylate homopolymers are investigated by differential scanning calorimetry (DSC) and optical microscopy and discussed in terms of relative lengths of the fluorinated chain and the hydrocarbon spacer between the acrylate moiety and the fluorinated chain. These compounds exhibit an intrinsic microphase-separation (Isotropic+Isotropic morphology) occurring between the fluorinated chains and the acrylate polymer backbone. It is shown that the enthalpy of mixing is a function of the length of the lateral fluorocarbon chains. The thermophysical behaviour of these materials may be regarded as demixed systems exhibiting an Upper Critical Solution Temperature. The photopolymerization process of one of the monomer is studied by isothermal photocalorimetry. High acrylate double-bond conversion and fast curing rates were obtained thus demonstrating the promising use of these materials for coating and film processing applications using UV-curing techniques.

Journal Article↗
PubMed2005

Synthesis and characterization of polyamide of trans-4-hydroxy-L-proline used as porogen filler in acrylic bone cement.

The aim of this study was to synthesize on a larger scale, an experimental polyamide based on an amino acid of trans-4-hydroxy-L-proline. The polyamide of trans-4-hydroxy-L-proline has been used as porogen filler (i.e., a hydrophilic pore generating material) in nondegradable acrylic bone cement. In in vitro studies, this hydrophilic filling component has been shown to form porosity within the acrylic bone cement in an aqueous environment. The formation of in situ porosity in the acrylic polymer matrix is believed to improve the fixation between the cement and the living bone. Namely, a porous structure can support bone ingrowth and strengthen the mechanical connection between the acrylic bone cement and the bone. The monomer, trans-4-hydroxy-L-proline methyl ester, was prepared from trans-4-hydroxy-L-proline by means of two steps, and the monomer was then polymerized to polyamide of trans-4-hydroxy-L-proline. The polymerization was carried out using a melt polycondensation method. The molecular weights (M(psi)) of the produced polyamides were between 1800 and 3600. The products were characterized by FTIR and (1)H-NMR spectroscopy.

Hydroxyproline↗
PubMed2006

Validation of the small-punch test as a technique for characterizing the mechanical properties of acrylic bone cement.

This paper examines the validity of using the small-punch test technique as a means of quantifying the mechanical properties of acrylic bone cement under different test conditions. The elastic moduli calculated using the small-punch test method were compared with data measured using the international standard for acrylic bone resin, ISO 5833. Conclusions from the study indicate that the small-punch test is a reproducible miniature specimen test method that can be used to characterize the mechanical properties of retrieved acrylic bone cement as used in total joint replacement surgery. Moreover, the test conditions were found to influence the elastic modulus of acrylic bone cement. The test temperature had a greater effect on the elastic behaviour of the bone cement than the test medium.

Bone Cements↗
PubMedDate not supplied

Microencapsulation of drugs by the coacervation technique using ethylcellulose and acrylate-methacrylate copolymer as wall materials.

In this study, ethylcellulose and acrylate-methacrylate copolymer (Eudragit RL 100, Eudragit RS 100) membranes were prepared by using appropriate types and amounts of plasticizers. Thirty percent and 20% of triacetin based on polymer weight were found to be appropriate plasticizers for ethylcellulose membranes and acrylate-methacrylate copolymer membranes, respectively. The ratios of 3:2 and 2:3 Eudragit RL 100: Eudragit RS 100 also gave transparent and flexible membranes. Cephalexin was chosen as a model drug. The coacervation technique was investigated for the preparation of cephalexin microcapsules. Ethylcellulose and acrylate-methacrylate copolymer corresponding to the above ratios were selected as wall materials of the microcapsules. The effects of core-to-wall ratios on the surface characteristics and dissolution of the microcapsules were also studied. The coacervation technique with ethylcellulose as wall material gave the higher yield (90%) of microcapsules. The release of cephalexin from ethylcellulose walled microcapsules was slow whilst the release from those of acrylate-methacrylate copolymer was faster. The increase of deposition of wall materials due to the decrease of the core-to-wall ratio resulted in a decrease of dissolution rate.

Cellulose↗
PubMed2000

[Direct measurement of nitric oxide levels in aqueous humor with selective iso-NO electrode under physiologic conditions and after phacoemulsification and artificial acrylic lens implantation in experiments on rabbits].

PURPOSE: Using a direct method, with selective and nitric oxide sensitive electrode Iso-NO, we estimated the level of the Nitric Oxide (NO) in the aqueous humor of the rabbit's eye after phacoemulsification and acrylic foldable lens implantation. We also analysed the NO level during early postoperative days between the 1st and the 5th postoperative day. The current methods of the NO level estimations are also considered. MATERIAL AND METHODS: We examined 30 gray rabbits (weighing 3.0-3.5 kg). Just before surgery, samples of aqueous humor were aspirated. Lens was extracted with phacoemulsification technique. In 15 eyes acrylic foldable IOL was implanted and 15 eyes were left aphacic. The aqueous samples were collected 1, 3, 5 days after surgery. Nitric oxide in each sample was determined with direct, selective nitric oxide sensitive electrode Iso-NO. Because of changing values of the NO concentration and its characteristic course, we expressed the concentration of NO in aqueous humor using field-under-curve method to compare it with control group. The results of our examination are presented in the absolute values. RESULTS: During physiological conditions the mean value of the field under curve of the NO concentration was estimated as 4987.29 +/- 895.89. After phacoemulsification with or without artificial lens implantation the level of the NO was higher as compared to the control group. After phacoemulsification and acrylic foldable lens implantation the highest level of NO was estimated on the 1st postoperative day as 6917.10 +/- 1199.72. During the examinations, the field under curve of NO concentration was estimated as 6246.63 +/- 327.02 and 5172.28 +/- 552.67 (on the 3rd and 5th days respectively). Only on the 1st and the 3rd postoperative day, the value of the field under curve of NO was significantly higher as compared with the control group. In contrast, after phacoemulsification without lens implantation the highest value of NO field under curve, was estimated on the 3rd postoperative days as 5801.44 +/- 344.45. During the examinations, the field under curve of NO concentration was estimated as 5115.30 +/- 796.11 and 4837.12 +/- 205.87 (on the 1st and the 5th days, respectively). Moreover, it was the only one day of examination with significantly higher value of NO field under curve as compared with the control. CONCLUSION: We came to conclusion that the level of nitric oxide in aqueous humor after phacoemulsification with or without artificial lens implantation is higher than in control group. The highest value of the field under curve was estimated on the 1st postoperative day after phacoemulsification and acrylic foldable lens implantation and on the 3rd postoperative day after phacoemulsification without lens implantation.

Animals↗
PubMed2003

[The injection of acrylic bone cement prevents bone collapse in the intercalar bones lacking bony support: an experimental sheep semilunar bone model].

OBJECTIVES: In a sheep semilunar bone model, we investigated whether collapse in the intercalar bones lacking bony support could be prevented by the injection of acrylic bone cement. METHODS: The study included 16 limbs of eight sheep. Preoperatively, anteroposterior and lateral views of the carpal joints in the fore limbs were obtained. The animals were divided into four groups. In group 1 (n=3) no surgical procedure was performed in the right semilunar bones, whereas the periosteum on the contralateral side was elevated (group 2; n=3). The first two groups were left as controls. In Group 3 (n=5) the left semilunar bones were filled with acrylic bone cement following decancellation of the bone, while the right semilunar bones were left decancellated (group 4; n=5). The sheep were monitored for three months. Radiographs of the carpal joints were obtained to evaluate collapse occurrence in the semilunar bones. Thereafter, the animals were sacrificed and the semilunar bones were excised for biomechanical and histological examinations. Osteonecrosis and cartilage damage were sought and resistance to compressive forces was investigated. RESULTS: Radiologically, the extent of collapse was statistically significant in the semilunar bones in group 4 (p<0.05). The use of acrylic bone cement was found to prevent collapse in group 3, with no significant difference being noted between preoperative and postoperative semilunar bone heights (p>0.05). Biomechanically, the least resistance to compressive forces was measured in group 4 (p<0.05). Histologically, cartilage damage and osteonecrosis were only seen in group 4. CONCLUSION: Our data suggest that the use of acrylic bone cement prevents collapse in the semilunar bones, without inducing any cartilage damage or osteonecrosis.

Animals↗
PubMed1986

[In vitro immune response to acrylic cement particles in patients with cemented joint replacements].

Immunological reaction to bone cement in tissue could be considered one of the important causes to induce the loosening of the prosthesis in patients with cemented prostheses. To study whether or not bone cement is immunogenic in human in vitro, the effect of acrylic cement particles on specific or non-specific blastformation reaction of peripheral blood mononuclear cells (PBM) or of non-adherent cells (NAC) was studied. Acrylic cement particles showed neither mitogenic nor cytotoxic effect on human PBM. No statistically significant enhancing effect of acrylic cement particles was found on specific or non-specific blastformation reaction of PBM or NAC from patients with cemented prostheses. No significant difference in those reactions to cement was seen between patients with loosened prostheses and with non-loosened prostheses. In some cases, however, acrylic cement particles showed significant enhancing effects on some macrophage-dependent blastformation reaction systems. As many of them were patients with cemented prostheses, it is highly possible that bone cement could induce significant macrophage-dependent immunological reaction in some particular population.

Adult↗
PubMed1978

Custon handles of dental acrylic to promote self-sufficiency of handicapped patients.

Dental materials lend themselves to a multitude of applications outside the dental profession. The inherent physical properties of dental acrylic (autopolymerizing methyl methacrylate) provide the potential for practical adaptation to a variety of functional problems. A technique using dental acrylic is described, which is easily adapted to a variety of circumstances, enabling digitally handicapped patients to perform independent functions. Specific stepwise instructions are provided for the fabrication of an easily customized acrylic-handled toothbrush and an efficient one-handed knife. The combination of dental acrylic and this flexible technique provides a useful tool in the alteration of appliances for handicapped persons.

Humans↗
PubMed2007

Using a nitrilase for the surface modification of acrylic fibres.

The surface of an acrylic fibre was modified with a commercial nitrilase (EC 3.5.5.1). The effect of fibre solvents and polyols on nitrilase catalysis efficiency and stability was investigated. The nitrilase action on the acrylic fabric was improved by the combined addition of 1 M sorbitol and 4% N, N-dimethylacetamide. The colour levels for samples treated with nitrilase increased 156% comparing to the control samples. When the additives were introduced in the treatment media, the colour levels increased 199%. The enzymatic conversion of nitrile groups into the corresponding carboxylic groups, on the fibre surface, was followed by the release of ammonia and polyacrylic acid. A surface erosion phenomenon took place and determined the "oscillatory" behaviour of the amount of dye uptake with time of treatment. These results showed that the outcome of the application of the nitrilase for the acrylic treatment is intimately dependent on reaction media parameters, such as time, enzyme activity and formulation.

Acetamides↗
PubMed2005

Development of acrylate-based monolithic stationary phases for electrochromatographic separations.

Organic monolithic stationary phases were synthesized in fused-silica capillaries. They were prepared by in situ polymerization under UV irradiation of various alkyl acrylates, 1,3-butanediol diacrylate, and 2-acrylamido-2-methyl-1-propanesulfonic acid in a ternary porogenic solvent. The resulting stationary phases were tested in CEC. The influence of UV irradiation energy on the resulting separative performances of the monoliths was studied. It was thus demonstrated that the use of hexyl acrylate rather than butyl acrylate and lauryl methacrylate gives highly efficient monoliths (more than 300 000 plates per meter) with optimized EOF. It was also confirmed that the mobile phase ionic strength may affect significantly the separation efficiency. The influence of the nature of the mobile phase organic modifier (ACN or methanol) on EOF, retention, efficiency, and selectivity was studied and differences were observed. Finally, the performances of monolithic stationary phases developed and optimized for CEC separations were evaluated in nanoLC.

Acrylates↗
PubMedDate not supplied

Electron beam-induced graft polymerization of acrylic acid and immobilization of arginine-glycine-aspartic acid-containing peptide onto nanopatterned polycaprolactone.

Electron beam- (EB-) induced graft polymerization of acrylic acid and the subsequent immobilization of arginine-glycine-aspartic acid (RGD) peptide onto nanopatterned polycaprolactone with parallel grooves is reported. A high concentration of carboxylic groups was introduced onto the polymer substrate by EB-induced polymerization of acrylic acid. In the coupling of the RGD peptide to the carboxylated polymer surface, a three-step peptide immobilization process was used. This process included the activation of surface carboxylic acid into an active ester intermediate by use of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (EDC) and N-hydroxysuccinimide (NHS), the introduction of disulfide groups by use of 2-(2-pyridinyldithio)ethanamine hydrochloride (PDEA), and final immobilization of the peptide via a thiol-disulfide exchange reaction. The extent of coupling was measured by UV spectroscopy. A preliminary study of the in vitro behavior of keratinocytes (NCTC 2544) cultured on the acrylic acid-grafted and RGD peptide-coupled surface showed that most cells grown on the coupled samples had a spread-rounded appearance, while the majority of cells tended to be elongated along the grooves on uncoupled substrates.

Acrylates↗
PubMed1997

Temperature-sensitivity of liposomal lipid bilayers mixed with poly(N-isopropylacrylamide-co-acrylic acid).

Temperature-sensitive drug release was examined using liposomes mixed with a copolymer of N-isopropylacrylamide (NIPAM) and acrylic acid [P(NIPAM-AA)] i.e., thermally responsive liposomes. P(NIPAM-AA) copolymers with transition temperatures of about 30, 33, 37, and 43 degrees C were synthesized by copolymerizing NIPAM and acrylic acid. Thermally responsive liposomes were prepared by mixing hydrophobically modified PNIPAM, or P(NIPAM-AA) with various liposomes, composed of egg phosphatidylcholine (PC), dimyristoylphosphatidylcholine (DMPC)/dipalmitoylphosphatidylcholine (DPPC) mixture (5: 5, w/w), DPPC, or distearoylphosphatidylcholine (DSPC). The release of a fluorescent marker, calcein, from liposomes was monitored by injecting the liposomal suspension at 17 degrees C into phosphate-buffered saline (PBS, pH 7.4) preadjusted to a temperature ranging from 20 to 46 degrees C. For liposomes of egg PC and DSPC, which do not undergo a phase transition during the temperature jump (17-->20-46 degrees C), the release temperature of the liposomes increased as the content of acrylic acid in the copolymers increased. The interaction between copolymer and lipid may induce the release of calcein at LCST of the copolymer. For DPPC liposomes, the release patterns were similar to those of egg PC and DSPC liposomes at 20-36 degrees C, where the phase transition of the liposomal membrane did not occur, while at 36-46 degrees C, where the phase transition of liposomal membrane occurred, the degree of release was almost the same. For DMPC/DPPC (5:5, w/w) liposomes, where the transition occurred below those of PNIPAMs, equally enhanced releases were observed as compared with PNIPAMs, even below the LCSTs of PNIPAMs. Thus, regardless of the occurrence of the transition of PNIPAMs, phase transition of DMPC/DPPC liposomes controlled the release of calcein.

1,2-Dipalmitoylphosphatidylcholine↗
PubMed1981

Allergic contact dermatitis due to an epoxy acrylate.

A printer developed allergic contact dermatitis due to epoxy acrylate resin. Incomplete cross-reactivity between four epoxy acrylate resins and a lack of cross-reactivity to epoxy resin was demonstrated. The epoxy acrylate resin has been shown to be a potent cutaneous sensitizer for the guinea-pig.

Acrylates↗
PubMed1998

Occupational dermatitis to ultraviolet-cured acrylic-based inks in computer hard disc manufacturing.

OBJECTIVE: Ultraviolet-cured acrylates and their various components and applications are reviewed in this report. METHODS: A 26-year-old woman involved in silk screening computer discs with ultraviolet-cured inks developed an acute allergic contact dermatitis on her hands and forearms. Patch testing revealed a number of strong reactions to epoxy resin and many multifunctional acrylates. RESULTS: The only one listed on the material safety data sheet to which she reacted was tripropyleneglycol diacrylate (TRPGDA). The other positive reactions likely represent cross-reactions. The positive reaction to epoxy is possibly relevant and attributable to nonhardened epoxy resin contaminant in the epoxy prepolymer. CONCLUSION: This case report shows a new application for ultraviolet-cured acrylate based inks in computer hard disc manufacturing.

Acrylates↗
PubMed1997

Influence of delayed injection time on the creep behavior of acrylic bone cement.

It has been proposed that creep of acrylic bone cement may contribute to loosening of cemented total joint replacements. If true, it is important that factors affecting creep of bone cement are identified. The objective of this study was to evaluate the effect of an operator-controlled variable, injection time, on the creep behavior of acrylic bone cement. Results from this investigation showed that injection time significantly (p < 0.0001) influenced creep behavior of bone cement. "Delayed" injection time of acrylic bone cement increased creep by approximately 5 times in 24 h compared to specimens prepared according to standard injection procedures.

Acrylates↗
PubMed2000

Attenuation of acoustic emission body waves in acrylic bone cement and synthetic bone using wavelet time-scale analysis.

This article addresses acoustic emission (AE) wave attenuation in acrylic bone cement and wave attenuation due to the existence of material interface between acrylic bone cement and sawbone. In this article, a series of tests were performed using standard pencil lead break sources. The attenuation features inside acrylic bone cement and sawbone materials and the attenuation due to the existence of material interfaces such as cement-cement and cement-sawbone were studied. In addition, the discrete wavelet-based signal energy decomposition method was introduced to examine detail breakdown of signal energy distribution of attenuation. From the tests, it was observed that the attenuation of AE signal was linear with respect to the wave travel distance for both energy and amplitude. Furthermore, AE energy attenuation was more sensitive than AE amplitude attenuation. In the analysis of attenuation due to material interfaces, the couplant plays a major role in reducing the attenuation at the interfaces. The attenuation at an interface composed by different material is less compared with an interface composed by the same material.

Acoustics↗