Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Rubber”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,027 records · Page 57Linked to original sources
PubMed1990

Glass-rubber transitions of cellulosic polymers by dynamic mechanical analysis.

The glass-rubber transition temperatures (Tg) of several cellulosic polymers [hydroxypropyl methylcellulose (HPMC), hydroxypropyl cellulose (HPC), hydroxyethyl cellulose (HEC)] have been examined using dynamic mechanical analysis (DMA). The melting temperatures of the above polymers were examined using a hot stage melting point apparatus. The primary Tg of three different grades of HPMC (3, 6, and 15 cps) were determined to be 160, 170, and 175 degrees C, respectively. The primary Tg of the HEC film was determined as 120 degrees C. The HPC film did not indicate a primary Tg. These cellulosic polymers also displayed secondary transitions. Hot stage melting of HPMC and HPC was observed at 225 to 254 degrees C and 190 to 195 degrees C, respectively. The HEC powder did not exhibit a melting temperature, but became darker at temperatures greater than 150 degrees C.

Cellulose↗
PubMed2005

NMR measurements of gaseous sulfur hexafluoride (SF6) to probe the cross-linking of EPDM rubber.

The effects of embedding gaseous SF6 into EPDM rubber were investigated using NMR methods. It was found that observed sorption and desorption processes follow the behavior of the dual mode sorption model. A strong correlation was found between EPDM cross-linking and transversal relaxation time of embedded SF6. EPDM samples with different cross-link densities, preliminarily determined by 1H transversal relaxation using the Gotlib model and Litvinov's method, were investigated using embedded SF6. The sensitivity of the 19F transversal relaxation rate of SF6 to the EPDM cross-link density variation was found to be at least 10 times higher than for 1H in the polymer chain. First experiments on probing the swelling effects in EPDM due to its contact with polar liquids have been performed.

Alkenes↗
PubMed2007

Using electrospray-assisted pyrolysis ionization/mass spectrometry for the rapid characterization of trace polar components in crude oil, amber, humic substances, and rubber samples.

We describe the use of electrospray-assisted pyrolysis ionization/mass spectrometry (ESA-Py/MS) to selectively ionize trace polar compounds that coexist with large amounts of nonpolar hydrocarbons in crude oil, amber, humic substances, and rubber samples. Samples of different origins are distinguished rapidly by their positive ion ESA-Py mass spectra without prior separation or chemical pretreatment. During ESA-Py analysis, the samples in their solid or liquid states were pyrolyzed at 590, 630 or 940 degrees C using a commercial Curie-point pyrolysis probe. The gaseous pyrolysates were transferred into a glass reaction cell. The polar compounds (M) in the pyrolysates were then ionized by electrospray ionization (ESI), yielding protonated molecules (MH+). Although the major components of the pyrolysates are nonpolar hydrocarbons, their lack of functional groups that can receive a proton in the ESA-Py source results in no hydrocarbon ion signals being produced; thus, the positive ions detected in ESA-Py mass spectra all result from trace polar components in the pyrolysates.

Amber↗
PubMed1982

Cancer incidence among Finnish rubber workers.

A follow-up study was carried out among workers in the processing and tire and tube fabrication departments of a Finnish rubber plant. A total of 1.331 workers were followed up for cancer through the files of the Finnish Cancer Registry from 1953 to 1976 (11,709 person years). The expected number of cancer cases was calculated on the basis of the age and sex-specific incidence rates for the urban population of the surrounding province. Twenty-one cancer cases were found against 18.9 expected (RR 1.1, 95% confidence interval 0.7-1.7). The risk of cancer of the digestive organs, respiratory organs, and urinary bladder was higher than expected, and the risk increased with the length of the follow-up time. However, the differences were not statistically significant.

Adult↗
PubMed1988

Serum and liver lipids of rats fed rubber seed oil.

Crude rubber seed oil (RSO) was incorporated at the 5% level in diets free of cholesterol or containing 1% cholesterol, respectively. These studies were initiated for the purpose of evaluating the palatability and potential toxicity of RSO. Corn oil was used as a control. A considerable amount of unsaponifiable matter was detected in RSO. In addition, RSO was found to possess a fatty acid profile which was fairly different from that of corn oil, primarily due to a much higher content of linolenic acid and a lower content of linoleic acid in RSO. No adverse effects on food intake and average daily gain were observed in rats fed RSO in both cholesterol-free and cholesterol diets. The presence of RSO in cholesterol-free diets results in lower (p less than 0.05) serum and liver total cholesterol levels than in control animals. A relative hypercholesterolemic effect compared to corn oil was observed however, when RSO was added to diets containing 1% cholesterol. In summary, the physicochemical properties of RSO as well as the presence of cholesterol in the diet are important factors in evaluating the cholesterolemic effect of RSO.

Animals↗
PubMed1995

[Historical cohort study in the German rubber industry: goals, study design and data collection].

A historical cohort study is carried out to investigate occupational hazards in the German rubber industry since 1991. We present and discuss the study objectives and study design features such as cohort definition, assessment of occupational exposure and selection of the reference population. Cohort enumeration, assessment of vital status and cause of death ascertainment are described. With approximately 2,800 deaths throughout the observation period 1981 to 1991 it will be possible also to study the occupational etiology of rare diseases.

Cause of Death↗
PubMed1994

New device for rubber band ligation of hemorrhoids.

We describe a new accessory for rubber band ligation of hemorrhoids. By using the new instrument it is possible to abscind the elastic band applied to the base of the hemorrhoidal node without entailing traumatic interventions. Of a total of 62 elastic ligatures, this device was used in the last 18 procedures, and provided excellent results. This instrument enables the surgeon to carry out the technique in a more accurate way and, if necessary, rectify "dangerous mistakes" that can occur while accomplishing the procedure itself.

Ambulatory Surgical Procedures↗
PubMed1980

Long-term evaluation of rubber ring ligation in hemorrhoidal disease.

Records of 266 patients who had undergone rubber ring ligation for hemorrhoidal complaints from 1969 through 1976 were reviewed to evaluate the long-term results. The minimum follow-up period was 36 months, with a mean of 60 months. Of the patients, 80 per cent were improved, with 69 per cent totally free of all symptoms. A subsequent hemorrhoidectomy was required in 7.5 per cent. Results were similar when either bleeding or prolapse was the primary indication for treatment. Patients who had a single band applied fared as well as those with two or more ligations.

Adult↗
PubMedDate not supplied

Reconstruction of the helical rim with the rubber band-conditioned postauricular tubed flap: a case report.

OBJECTIVE: A case with posttraumatic tissue loss of the auricle is presented, where successful reconstruction with the aid of a tubed flap is achieved by gradual lysis within three stages. BACKGROUND: Helical rim losses may be reconstructed with a tubed flap created from postauricular tissue. METHOD: The vascularity of the tubed flap was increased with the intermittent application of a rubber band tourniquet. CONCLUSION: The use of a tourniquet before completing the third stage of the helical rim reconstruction may enhance the reliability of this procedure.

Adult↗
PubMed2006

An epidemiological study of talc-related respiratory morbidity among employees of a rubber industry in Shiraz-Iran.

OBJECTIVES: The main purpose of this study was to assess and characterize the pulmonary reactions associated with occupational exposure to talc dust. METHODS: Ninety-seven talc workers and 110 unexposed employees as the reference group were randomly selected from a local rubber industry. Standardized respiratory questionnaires were administered to the subjects, they underwent chest X-ray and were examined by a specialist for any possible respiratory abnormality to be diagnosed. Furthermore, pulmonary function tests (PFTs) were measured just before and after the work shift. Moreover, to assess the extent to which workers had been exposed to talc dust, using standard methods, inhalable and respirable dust concentrations were measured in different dusty worksites. RESULTS: The average (mean +/- SD) age (years), weight (kg), height (cm) and duration of exposure to talc dust (years) for the exposed group were 35.8 +/- 6.75, 73.1 +/- 9.2, 172.3 +/- 5.9 and 11.79 +/- 5.3, respectively. The corresponding values for the non-exposed group were 36.1 +/- 6.87, 73.36 +/- 8.1, 173.2 +/- 5.7 and 0 +/- 0, respectively. Atmospheric concentrations of inhalable and respirable talc dust were estimated to be 41.8 +/- 23.52 and 19.8 +/- 8.04 mg/m(3) (mean +/- SD), respectively. Talc exposed subjects had a significantly higher prevalence of respiratory symptoms. Similarly, PFTs revealed that exposure to this lubricating agent was associated with significant decreases in the mean percentage predicted of vital capacity (VC), forced vital capacity (FVC) and forced expiratory volume in the first second (FEV(1)). Likewise, there was a general tendency for VC, FVC and FEV(1) to decrease as estimated cumulative exposure (years worked) increased. Moreover, there was an acute reduction in some parameters of pulmonary function such as VC, FVC and FEV(1), over the work shift. Chest radiographs of exposed workers showed that pneumoconiosis profusions were between p 0/0 and p 2/1 according to the ILO 1980 chest X-ray classification. CONCLUSIONS: These results that are in full agreement with our preliminary observations, support the notion that occupational inhalation exposure to talc is associated with both acute and chronic respiratory disorders and induces bronchitis and interstitial lung disease.

Adult↗
PubMed2000

Challenge from methacholine, natural rubber latex, or 4,4-diphenylmethane diisocyanate in workers with suspected sensitization affects exhaled nitric oxide [change in exhaled NO levels after allergen challenges].

OBJECTIVE: Nitric oxide (NO) levels in the exhaled air of asthmatic patients have been shown to be increased. This observation has also been reported in workers who are allergic to laboratory animals. To determine if a challenge test with natural rubber latex (NRL) or 4,4'-diphenylmethane diisocyanate (MDI) would also produce an increase of NO exhalation in sensitized patients, we carried out this study. METHODS: Nine subjects with suspected occupational asthma were exposed to MDI, and 18 took part in a challenge test with gloves powdered with NRL. Nineteen subjects underwent a challenge test with methacholine (MCh). Exhaled NO was measured by a modified chemiluminescence analyzer according to the European Respiratory Society guidelines. RESULTS: We found that there was a decrease in exhaled NO concentrations 16-18 h after MCh challenge testing and subsequent bronchodilation with salbutamol, in three subjects. Three of nine participants had a significant immediate bronchial obstruction after exposure to MDI, of those three, two had MDI-specific IgE antibodies. After 22 h, their levels of exhaled NO had increased > 10 parts per billion (ppb). Eight of the 18 subjects participating in the NRL challenge test displayed an NO concentration increase of at least 10 ppb after 22 h (seven had NRL-specific IgE antibodies). A significant decrease in the one-second forced expiratory volume (FEV1) was documented in four of those eight participants after NRL challenge. CONCLUSIONS: There was no clear relationship between bronchial response, substance-specific IgE antibodies and an increase in exhaled NO levels. However, there was a tendency for subjects with substance-specific IgE antibodies and bronchial reaction to develop an increase in exhaled NO concentration. Further studies are needed to determine if analysis of NO from the lower respiratory tract can become a useful non-invasive tool for detecting lower airway inflammatory response even before clinical symptoms occur.

Adolescent↗
PubMed2002

In-situ chemical analyses of trans-polyisoprene by histochemical staining and Fourier transform infrared microspectroscopy in a rubber-producing plant, Eucommia ulmoides Oliver.

The localization of polyisoprene in young stem tissues of Eucommia ulmoides Oliver was investigated by histochemical staining and Fourier transform infrared (FT-IR) microspectroscopy. The fibrous structures were stained with Oil Red O. FT-IR microspectroscopic analysis proved that the fibrous structures were trans-polyisoprene. Granular structures stained with the dye, and characteristic absorptions at 2,960 cm(-1) and 1,430 cm(-1) in FT-IR suggested that trans-polyisoprene accumulated in the vicinity of the cambium layer. We have thus successfully shown for the first time the localization of trans-polyisoprene in plant tissues, and our histological investigation allowed us to presume the main sites of biosynthesis and accumulation of trans-rubber. Furthermore, a new technical approach, the preparation of sections using an electronic freezing unit and the in situ analysis of polyisoprene using FT-IR microspectroscopy, is demonstrated to be a promising method for determining the accumulation of polyisoprene as well as other metabolites.

Azo Compounds↗
PubMed2006

Ringed silicon rubber attachment prevents laparoscopic surgeon's thumb.

BACKGROUND: This investigation, using the nerve conduction study, aimed to quantify the degree of laparoscopic surgeon's thumb, and to evaluate the effect of the ringed silicon rubber attachment (RSRA) developed by the authors. METHODS: For the study, 26 residents or students performed surgical tasks (grasping and dissecting) using both the laparoscopic forceps with RSRA and the conventional instrument. The paresthesia was evaluated with a severity score obtained by interview and measurement of sensory nerve conduction velocity (SCV). RESULTS: The mean severity score was 2.57 +/- 0.58 m/s for the conventional forceps and 1.05 +/- 0.80 m/s for the forceps with RSRA (p < 0.01). For the grasping task with the conventional forceps, the mean SCV was 58.3 +/- 2.81 m/s before and 54.8 +/- 2.83 m/s after the task (p < 0.01), whereas for the dissecting task, the corresponding values were 57.5 +/- 2.46 m/s and 56.1 +/- 2.93 m/s (p < 0.01). For the grasping task with the RSRA, the mean SCV was 57.1 +/- 3.33 m/s before and 55.9 +/- 3.18 m/s after the task (p < 0.01), whereas for the dissecting task, the corresponding values were 55.7 +/- 4.59 m/s and 55.8 +/- 3.50 m/s (nonsignificant difference). CONCLUSIONS: Laparoscopic surgeon's thumb was induced by compression of the lateral digital nerve. The RSRA significantly reduced the degree of paresthesia.

Adult↗
PubMed1990

Percutaneous mitral valvuloplasty with a single rubber-nylon balloon (Inoue balloon): long-term results in 71 patients.

The first 71 patients with rheumatic mitral stenosis who successfully underwent single rubber-nylon balloon (Inoue balloon) percutaneous mitral valvuloplasty (PMV) from November 1985 to August 1988 had a mean follow-up period of 27.1 +/- 11.6 months (range, 14 to 48 months). Functional status before PMV was New York Heart Association (NYHA) functional class IV in two, class III in 38, and class II in 31. Pre and post PMV and follow-up mean diastolic mitral gradient by catheter method was 17.5 +/- 6.9, 2.7 +/- 3.5, and 3.3 +/- 3.4 mm Hg (p less than 0.001 pre versus post PMV and pre PMV versus follow-up; and p greater than 0.005 post PMV versus follow-up). By Doppler method the mean diastolic gradient was 17.4 +/- 5.5, 8.5 +/- 4.7, and 9.2 +/- 4.1 mm Hg, respectively (p less than 0.001 pre versus post PMV and pre PMV versus follow-up; and p greater than 0.05 post PMV versus follow-up). Mitral valve area was 1.12 +/- 0.26, 2.04 +/- 0.41, and 1.92 +/- 0.45 cm2, respectively (p greater than 0.001 pre versus post PMV and pre PMV versus follow-up; and p less than 0.05 post PMV versus follow-up). The phonocardiographic and vectorcardiographic studies and cardiopulmonary exercise testing showed significant improvement after PMV and at follow-up. At follow-up the NYHA functional class was 1 in 57 patients, class II in 13, and class III in one patient with severe mitral valve calcification and subvalvular fusion, in whom restenosis occurred 18 months after PMV.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1996

High incidence of bites and stings by snakes and other animals among rubber tappers and Amazonian Indians of the Juruá Valley, Acre State, Brazil.

Among forest-dwelling Amazonian Indians and rubber tappers (seringueiros) of the Juruá valley in Acre State, north-western Brazil, snakebite is an important cause of morbidity and death. Overall, 13% of a surveyed population had been bitten during their lifetime. Seventeen per cent of Katukina Indians, but only 8% of Ashaninkas, had been bitten by snakes reflecting, perhaps, different levels of traditional knowledge of the forest and its dangers. Most bites occurred in the jungle or on jungle trails (56%), while people were working (41%) or walking (26%), and were inflicted on the feet (54%). Ninety per cent of bite victims received treatment, usually traditional (93%); the majority (80%) recovered fully. Mortality was estimated at about 400 deaths per 100,000 population per lifetime. Bites and stings from other venomous forest and river animals, especially the freshwater sting ray (Potamotrygon sp.), were also extremely common. One death from an ant bite was recorded.

Animals↗
PubMed1993

A natural rubber drainage tube with antithrombogenic lumen surface.

A drainage tube was made by radiation vulcanization of a high polymeric substance based on natural rubber elastomers. Pentosan polysulphate sodium bound to a carrier substance (synthetic type 4A or 13X zeolite) was incorporated in the drainage tube which was then tested for its anticoagulant properties during perfusion with Tris buffer solution, citrated plasma, and blood, resp. The amount of pentosan polysulphate sodium released from the tube walls during perfusion with human citrated plasma in an open circulatory system was sufficient to exert an anticoagulant effect on the streaming plasma. This effect was corroborated by prolonged thrombin times and by unclottability in case of recalcified plasma samples in thrombelastographic studies. The antithrombogenicity test according to Chandler in a closed circulatory system revealed thrombus formation times (TFT) of more than 24 h (control: TFT = 1-3 min in native blood).

Animals↗
PubMed1979

Mutagenicity and metabolism studies on 12 thiuram and dithiocarbamate compounds used as accelerators in the Swedish rubber industry.

12 thiuram and dithiocarbamate compounds used in the rubber industry as accelerators, and to some extent as sources of sulfur, were tested, as well as carbon disulfide, a metabolite found in vivo after dithiocarbamate treatment, for mutagenicity in Salmonella typhimurium. A mutagenic effect on the base-substitution-sensitive strains TA1535 and TA100 was found for 7 compounds. The most potent directly acting mutagens were: tetramethylthiuram disulfide (TMTD), zinc dimethyldithiocarbamate (ziram), cadmium diethyldithiocarbamate and zinc diethyldithiocarbamate. Tetraethylthiuram disulfide (TETD), also known as Antabus, and carbon disulfide were non-mutagenic. The relatively low direct mutagenic effect of tetramethylthiuram monosulfide (TMTM) was enhanced in the presence of a metabolizing system (S9 mix). A hypothesis is given regarding the activation process of the monosulfide TMTM.

Animals↗
PubMed1984

Biological monitoring of workers in the rubber industry. I. Chromosomal aberrations and sister-chromatid exchanges in lymphocytes of vulcanizers.

To evaluate the possible genetic consequences of the industrial exposure among the vulcanizers of a rubber plant we measured the in vivo levels of chromosomal aberrations and sister-chromatid exchanges in peripheral lymphocytes of 34 vulcanizers and in an adequate control population. The observed chromosomal aberration frequencies were 1.9 +/- 1.4 aberrations/100 cells in the exposed group and 2.1 +/- 1.5 aberrations/100 cells in the controls. No difference was found between the two groups for the mean value of sister-chromatid exchanges (5.2 +/- 1.3 in the exposed, 5.2 +/- 0.7 in the control group). Cigarette-smoking was clearly associated with increased sister-chromatid exchange frequencies both in the exposed and in the control groups, while chromosomal aberration frequencies were not correlated with smoking habits.

Chromosome Aberrations↗