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At least 1,603 records · Page 89Linked to original sources
PubMed1990

[Conventional section study of thoracic organs. Improved diagnosis with compensation filters of anatomically molded acrylic glass containing lead].

The diagnostic value of conventional chest tomography was improved dramatically by filters, manufactured of transparent acrylic glass containing 120 or 240 mu lead aquivalent (DuPont, Neu Isenburg). A perfect compensation of the chest anatomy and pathology in ap-pulmonary tomography can be done easily because the anatomically shaped filters are mobile-mounted in front of the x-ray tube. The position of each filter is visible on the patient's skin. This enables the radiographer to routinely obtain tomograms with diagnostic density values ranging from S = 0.4-2.0. For 6 characteristic areas this was measured in 98%. Such films allow subtle analyses of the tracheal and bronchial wall, the segmental bronchi and pulmonary vessels or pathologic lesion. Compared to cross-sectional imaging CT and MRT, the frontal tomogram shows several aspects of the hilar compartment more clearly because the main central pulmonary structures are located primarily craniocaudally. The conventional tomogram therefore supplies additional views with high spatial resolution. The clinical importance of diagnostic information obtained with ap-tomography using the ATCF are shown in 4 cases. In our hospital, the thoracic surgeon therefore demands conventional tomography with the ATCF to complete staging of benign or malignant chest disease preoperatively.

Acrylates↗
PubMed1989

[Application of isocyanate separating agent for acrylic resin].

The most widely used agents for separating acrylic resin from gypsum molds are the water-soluble alginates, which produce a very thin water- and organic solvent-insoluble calcium alginate film on the gypsum surface. In the present study, a new type of separating agent, an isocyanate type coating agent, was developed and it's properties were investigated. This coating agent is composed mainly of trimethylol-propane-tolylenediisocyanate and ethyl-acetate, with a small amount of bis-tributyl-tin oxide as catalyst. At first, a thin film was formed on the surface by application of the agent, and then alkyl-phosphate was applied to this film to ensure easy separation of the cured resins from the molds. The molds treated with this separating agent had a glossy, hard surface. The surface of the cured resins treated in this way was glossier and smoother than that of resin treated with the water-soluble alginates.

Acrylic Resins↗
PubMed1989

[Adhesive efficiency of new bonding agents to dentin on bonding agent using urethane acrylate oligomer].

The tensile bond strength of new bonding agents on human dentin treated with 37% phosphoric acid solution for 60 sec to a photocurable composite resin was measured and the fractured surface was then observed by SEM. The new bonding agents consisted of various 20 wt% high molecular monomers (MW. 1500, 5000, urethane acrylate oligomer) as a base monomer. The best bonding agent was a mixture of 20 wt% 1500 molecular monomer as a base monomer and the value of the tensile bond strength was 91 +/- 17 kgf/cm2. The tensile bond test and SEM image of the fracture surface suggested that a high molecular monomer as a base monomer promoted the adhesive efficiency to human dentin.

Acrylic Resins↗
PubMed1989

The effect of reinforcing fibres in denture acrylics.

Since the early 1970's, various fibre reinforcement systems have been used to enhance the mechanical properties of denture base acrylics. The research conducted to date on fibre reinforcement systems for use with Poly(methylmethacrylate) (PMM) denture base material is reviewed and evaluated.

Acrylic Resins↗
PubMedDate not supplied

[Loss of interproximal periodontal tissue. A clinical solution with construction of a removable acrylic resin appliance].

One of the problems of difficult solution in clinic are the tissue lost from periodontic surgery procedures. The purpose of this survey is to help find the solution of this problem, and we show a case where the patient has great interdental tissue lost after surgery and was solucionated with an acrylic resin appliance. The clinic results prove the efficiency of the appliance, diminishing or having the hole esthetic and phonetic problem solucionated, besides the low-cost of its confection and also allows the patient to have a good plaque control.

Acrylic Resins↗
PubMedDate not supplied

[Quantitative evaluation of reflectance of some acrylic resins mixed with powdered enamel and/or natural quartz].

Autopolymerizing acrylic resins for temporary prothesis and crown veneering have been mixed with dental enamel and/or quartz in powder form in different percentages, to simulate optical properties of the tooth. The analysis of our measurements of apparent reflectance of those mixings show that is possible to approximate several of those values to the ones corresponding to natural tooth; being sufficient to follow the formulation given++ in this paper.

Acrylic Resins↗
PubMed1986

Anticoagulant effect of sulphated poly/vinyl alcohol-acrylic acid/copolymers.

Copolymers of poly/vinyl alcohol-acrylic acid/ with various content of sulphate and carboxyl groups have been synthetized and tested for their in vitro effect on blood coagulation. The results indicate that the sulphated copolymers display an inhibitory effect but there is a requirement in the charged groups of about 20% in the molecule to possess effective anticoagulation. The biochemical mechanism of their actions is complex, i.e. the inhibition of blood clotting is a consequence of both the accelerated inactivation rate of thrombin by antithrombin-III and a direct inhibitory effect on the thrombin-fibrinogen reaction. Moreover, additional effects may occur on other blood coagulation enzymes than thrombin, depending on the chemical composition of the copolymers.

Acrylic Resins↗
PubMed1986

Revlens: a new, soft acrylic rubber extended-wear contact lens.

Revlens is a new, soft acrylic rubber extended-wear contact lens. We fitted 21 eyes in 15 patients. The indications included 15 eyes in 10 patients with aphakia due to congenital cataracts. The developmental cataracts were associated with persistent hyperplastic primary vitreous, Down's syndrome, microphthalmos and Peter's anomaly. The remaining five patients included one Tyrosinase negative oculocutaneous albino and four anisometropic amblyopes. Three of the aphakic patients were unable to wear this lens. One preferred her previous rigid lens, another refused any contact lens and went back to glasses, and a third did not adapt to the lens because of social circumstances. Thus 12 of the 15 patients (80%) who were monitored for at least 6 months (average: 9 months) readily accepted this new lens.

Acrylates↗
PubMed1986

Synthesis and antimicrobial properties of new aroyl-acrylic esters of polyethylene glycols.

Eight new aroyl-acrylic esters of polyethylene glycols were prepared using different synthetic ways. They are supposed to possess a higher activity as antimicotic agents for topical use, by favouring skin absorption. Except in few cases, the antimicrobial activity of the oligomeric derivatives resulted generally decreased in vitro, in comparison to simple alkyl esters previously prepared. However, only pharmacological screenings for antimicotic activity in vivo will give a definite response on whether the new derivatives are advantageous for topical use.

Acrylates↗
PubMed1986

[Comparative study of the antineoplastic and immunoadjuvant activity of acrylic acid (co)polymers].

The paper deals with the carcinostatic and immunomodifying action of synthetic polyelectrolytes containing acid and basic groups as well as of polyampholytes and nonionogenic polymers. Polyacrylic acid was found to possess the highest antitumour and adjuvant activity. The antitumour effect of polyacrylic acid increases with its molecular mass. Introduction of other polymers into a polymer chain of acrylic acid results in a decrease in its antitumour and immunoadjuvant action.

Acrylic Resins↗
PubMed1986

Biliary excretion and organ distribution of 14C radioactivity after 14C-2-ethylhexyl acrylate administration in rats.

Rats were intravenously administered (14C)-2-ethylhexyl acrylate at the dose 10 mg/kg or 50 mg/kg b. w. Biliary excretion of 14C-radioactivity was followed in 1-3 hour intervals within the first 24 hours after administration. The rats were then sacrificed and distribution of 14C-radioactivity was followed in some organs. Highest radioactivity was found in liver, less in the kidneys and the least in the brain. A significant increase of bile flow was observed. In the 24-hour intervals 2.2% of the dose was eliminated via bile at both dosages, most of it (83%) during the first 3 hours.

Acrylates↗
PubMed1985

Quantitative relationships between lipophilicity and mutagenic effects of N-substituted amides of 3-(5-nitro-2-furyl)-acrylic acid on Salmonella typhimurium.

Mutagenic effects of 10 N-alkylamides of 3-(5-nitro-2-furyl)-acrylic acid were assessed in two strains of Salmonella typhimurium TA100 (rfa+ and rfa-). Experimental data were confronted with physiologically based compartment model comprising passive membrane transport, metabolical inactivation in cytoplasm and formation of a reactive intermediate which is responsible for receptor modification. The quantitative dependences observed between mutagenicity and lipophilicity indicate that, in both cases, the drug-receptor interaction takes place in a hydrophobic compartment localized in the cytoplasm. The mutagenic potency of some derivatives was influenced also by stericity.

Acrylates↗
PubMed1986

Inhibition of the positive atrial chronotropic effect of isoproterenol by exposure to an acrylate floor finish.

Application of a commercial acrylate sealer/finish to the floor of our animal quarters resulted in almost complete elimination of the positive chronotropic response of the hypoxic rat atria to isoproterenol. Forty-eight hours exposure to this sealer/finish decreased sensitivity to isoproterenol by approximately 1000-fold and decreased maximal response by 70%. The elimination of the response to isoproterenol was associated with the resin portion of the sealer/finish and was reversible on removal of the rats from exposure to the product.

Acrylates↗
PubMed1985

Application of lead-acrylic compensating filters in chiropractic full spine radiography: a technical report.

X-raying the entire spinal column in the standing position in a single exposure (mainly the AP projection) is an often-used chiropractic radiography procedure which has also found some application in medical scoliosis screening program. Aside from any controversy of clinical objectives or medical necessity, the primary agreed-upon requisite for such procedure is twofold; achieving the best possible film image quality with the least amount of radiation exposure to the patient. A popular method of accomplishing this objective is by the use of collimator-attached devices designed to selectively filter the primary x-ray beam in accordance with regional variations of body thickness and/or density. This study was conducted to evaluate the use of a new lead-acrylic filter system (a prior model of which had previously been evaluated for its use in medical radiography) under specialized chiropractic conditions. In comparison to other available systems, it was concluded that this new system; a) is generally equivalent in its radiation dose reduction capabilities; b) is capable of producing full spine radiographs with good to above average image quality; and c) is appreciably easier to use.

Acrylates↗
PubMed1976

Enzymatic attack on side chains of synthetic polymers. Chymotrypsin-catalyzed hydrolysis of specific substrate groups attached to acrylamide or acrylic acid co-polymers.

Three vinyl monomers, M-1, M-3, and M-5, in which L-phenylalanine p-nitroanilide was acylated with CH2==CHCONH(CH2)nCO--(n = 1, 3, 5) were synthesized. They were co-polymerized with a large excess of acrylamide (co-polymers PAm-1, PAm-3, and PAm-5) and with a large excess of acrylic acid (co-polymers PAc=1, PAc-3, and PCc-5). In addition, M-5 was co-polymerized with acrylamide containing 2.8 mol % of the hydrophobic monomer N-acrylyl-1-naphthylamine (co-polymer PAm-5N). The rates of the chymotrypsin-catalyzed hydrolysis of the nitroanilide groups of M-5 and the various co-polymers were determined over a range of pH. For some of the systems data were also obtained over a range of substrate concentrations to derive values for Vmax and Km. Results obtained with PAm-5 were found to be independent of the chain length of the co-polymer. At pH 7, 25 degrees and with 2.7 X 10(-6) M enzyme, Vmax values for M-5, PAm-k, PAm-5N, and PAc-5 were 5.5, 5.5, 10, and 3.6 X 10(-8) M/S, while Km values were 8.5, 16.5, 10, and 2.2 X 10(-5),respectively, With PAc-5, the pH activity profile was shifted to higher acidities as compared to the profiles obtained with M-5 and PAm-5. The susceptibility of the co-polymers to chymotrypsin attack decreases sharply with a decreasing spacing of the L-phenylalanine p-nitroanilide residue from the backbone of the polymer chains.

Acrylamides↗