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At least 919 records · Page 51Linked to original sources

PubMed2000

A new polyurethane anal plug in the treatment of incontinence after anal atresia repair.

UNLABELLED: 38 totally or partially incontinent patients following imperforate anus repair (age 6-15 years) tested a new polyurethane (PU) anal plug against another, widely used anal plug (PVA) in a randomized crossover trial. Plugs were tested 3 weeks each, data concerning bowel habits, handling and plug-related problems were collected by questionnaire before trial, at time of product change and after trial. RESULTS: 15 of 38 patients did not complete the protocol, among them 6 with anal canal diameters too small for the smallest plug. During plug use, patients experienced enhanced awareness of repletion and urge. Stool consistence did not change in 82% of patients. There were no changes in children constipated prior to study (n = 8/23). 12,123 children were absolutely clean during use of either plug. 15 patients (68%) using the PU plug and 10 (45%) using the PVA plug felt secure from soiling during plug use. 74% of patients preferred the PU plug. Painful plug insertion, a feeling of pressure inside the anal canal and painful plug removal were reported with both plugs, but were less frequent with the PU plug. CONCLUSION: Anal plugs, regardless of their make, offer absolute cleanliness for periods of several hours to 66% of our incontinent patients. The PU plug (Conveen, Coloplast) is preferred by the patients and offers greater security than the PVA plug.

Adolescent↗

PubMedDate not supplied

Clinical findings for residents near a polyurethane foam manufacturing plant.

Clinical findings for 38 community residents who complained of symptoms they attributed to exposure to air emissions from nearby fiber processing and polyurethane foam manufacturing facilities are reported. Common complaints included headache, mucosal irritation, shortness of breath, chest tightness, and wheezing. Airway hyperreactivity, measured by methacholine challenge, was observed in 8 individuals (22% of those tested), who also reported temporal relationships between exposure to visible emissions or odors and symptoms consistent with environmentally induced asthma. Six individuals (18.2%) had antibodies to at least 1 of the 3 common industrial diisocyanates. The number of individuals with antibodies to diisocyanates, coupled with the absence of other diisocyanate exposure, was highly suggestive of environmental exposure. The findings raised concern that some residents may have become sensitized to toluene diisocyanate.

Adult↗

PubMedDate not supplied

Preparation and characterization of microcapsules of water-soluble pesticide monocrotophos using polyurethane as carrier material.

Microencapsulation of the water soluble pesticide monocrotophos (MCR), using polyurethane (PU) as the carrier polymer, has been developed using two types of steric stabilizers, namely PLMA macrodiol and PLMA-g-PEO graft copolymer. The microencapsulation process is carried out in non-aqueous medium and at a moderate temperature to avoid any chemical degradation of monocrotophos during the encapsulation process. Microcapsules were characterized by optical microscopy and SEM for particle size and morphology, respectively. The effects of loading of MCR, crosslinking density of PU, and nature of steric stabilizer on the release of MCR from PU microcapsules have been studied.

Algorithms↗

PubMed2004

Use of a water-vapour permeable polyurethane film (omiderm) in the non-surgical treatment of aplasia cutis congenita.

Aplasia cutis congenita is characterised by congenital absence of all layers of skin, and most commonly affects the scalp. It is often associated with absence of the bone and dura underlining the defective scalp. In this report, we present the result of use of a water-vapour permeable polyurethane film (Omiderm) together with absorbant fine mesh gauze impregnated with 3% bismuth tribromophenate (Xeroform) in the treatment of a cranial defect in a newborn baby of low birth weight, who could not be operated on because of associated medical problems.

Bandages↗

PubMed2001

Polyurethane gel liner usage in the Oxford Prosthetic Service.

The objective was to investigate which lower limb amputees are using Alpha polyurethane gel liners and the effects of these on comfort and suspension of their prosthesis. A retrospective study was carried out of case records of all patients issued with Alpha cushion and locking liners between 1997 and the end of January 1999. The type of liner used was compared with age, sex, level and cause of amputation, time since amputation, comfort and suspension. Modified Stanmore/Harold-Wood mobility grades; duration of use and number of liners issued per patient were recorded. Sixteen (16) patients were identified who had been prescribed Alpha cushion liners. Improved comfort was reported by all. Forty (40) patients were identified who had been prescribed Alpha locking liners. Twenty (20) of these reported improved comfort and 10 improved suspension. The average time since amputation was 18.5 years for those using cushion liners and 14.1 years for locking liner users. Fifty-two (52) of all 56 patients using Alpha cushion and locking liners had mobility grades of 4 or more. Trauma was the most common cause of amputation. This group is a relatively mobile group of amputees. All those using cushion liners reported improved comfort. Some of the locking liner users reported improved comfort and suspension but this was not universally the case.

Adolescent↗

PubMed1981

Evaluation of polyurethane foam as a trapping medium for herbicide vapor in air monitoring and worker inhalation studies.

Polyurethane foam was an efficient adsorbent for trapping vapors of butyl esters of 2,4-D (2,4-dichlorophenoxyacetic acid) and triallate (S-(2,3,3-trichloroallyl)diisopropylthiocarbamate) in high volume air monitoring studies and of butyl esters of 2,4-D, iso-octyl ester of 2,4-D, n-butyl ester of 2,4,5-T (2,4,5-trichlorophenoxyacetic acid), bromoxynil octanoate (2,5-dibromo-4-hydroxybenzonitrile), triallate, and trifluralin (alpha, alpha, alpha-trifluoro-2,6-dinitro-N-N-dipropyl-p-toluidine) in short-term, low volume, worker inhalation exposure studies. The collected herbicide vapor was readily desorbed under soxhlet extraction with n-hexane and subsequently analyzed with electron-capture GLC. The overall efficiencies, for both trapping and extraction, were over 90%, using a single plug, for all herbicides, except triallate. In the case of triallate, two plugs in series were required for efficient trapping under the high volume air monitoring situation.

2,4-Dichlorophenoxyacetic Acid↗

PubMed2000

Exposures to 1,6-hexamethylene diisocyanate during polyurethane spray painting in the U.S. Air Force.

1,6-Hexamethylene diisocyanate (HDI) exposures were measured during polyurethane enamel spray painting at four Air Force bases. Breathing zone samples were collected for HDI monomer and polyisocyanates (oligomers) using three sampling methods: NIOSH Method 5521, the Iso-Chek sampler, and the total aerosol mass method (TAMM). Exposures to HDI monomer are low when compared to current occupational exposure limits; the highest 8-hr time-weighted average (TWA) exposure found was 3.5 micrograms/m3, below the American Conference of Governmental Industrial Hygienists (ACGIH) threshold limit value (TLV) of 34 micrograms/m3. HDI oligomer levels were higher; mean task exposures indicated by either the Iso-Chek sampler or TAMM are above the Oregon ceiling limit of 1 mg/m3. Eight-hour TWA exposures, however, were much lower, with only one exceeding the Oregon standard of 0.5 mg/m3. Poor worker practices commonly observed during this study included: standing in downwind positions so paint overspray passed through breathing zones; spraying toward other painters; and using excessive paint spray gun air cap pressures. Workers should stand in upwind orientation relative to the aircraft being painted, causing overspray to move away from the painter's breathing zone; adjust their position to prevent spraying other painters or limit paint application to one worker at a time; and use air cap pressure gauges prior to spraying to limit spray gun air cap pressures and reduce paint overspray generation rates. These improved techniques will result in reduced worker exposures to isocyanates.

Aerosols↗

PubMed2004

Assessment of softball bat safety performance using mid-compression polyurethane softballs.

There is currently much debate about the safety of the sport of softball. Batted-ball speed and average pitcher reaction time are factors often used to determine safe performance. Batted-ball speed is shown to be the most important factor to consider when determining safe play. Average pitcher reaction time is explained and directly correlated to batted-ball speed. Eleven aluminum multi-wall, three aluminum single-wall and two composite softball bats were tested with mid-compression polyurethane softballs averaging 1721+/-62 N/6.4 mm to represent the relative bat-ball performance for the sport of slowpitch softball. Nine men and six women were chosen for this study out of a test group of over three hundred slowpitch softball players. On average, aluminum bat performance results were within the recommended safety limits established by the national softball associations. However, when composite bats were used, their performance results exceeded the recommended safety limits which can pose a significant safety risk. Using aluminum softball bats, batted-ball speeds ranged from 80 to 145km x h(-1) Using composite softball bats, batted-ball speeds ranged from 146 to 161 km x h(-1). The scientific relevance of this study is to provide performance information that can lead to injury prevention in the sport of softball.

Acceleration↗

PubMedDate not supplied

Construction and evaluation of an aerosol generating apparatus for combustion products from polyurethane foam.

A system has been constructed and evaluated for generating aerosols from combustion or pyrolysis of various cross-linked polymers. The system consists of an aerosol generator and an aerosol chamber with a sampling compartment designed for various samplers and sampling probes. A geared electric motor assembly is used to lower a polymer strip into the controlled atmosphere of a quartz-lined furnace. The polymer used in this investigation was a polyurethane foam (PUF) based on toluene diisocyanate (TDI). Combustion of the PUF was conducted in filtered air at a temperature of 300 degrees C. The particle number concentration of the generated aerosol was measured by light scattering in the particle size range from 0.1 micron to greater than 5 microns. Air samples were collected periodically in impinger flasks using dibutylamine (DBA) in toluene as derivatization reagent. The TDI-DBA derivatives from the impinger samples were analyzed with high performance liquid chromatography. The aerosol generating system was found to generate a stable, reproducible, and predictable concentration of particles and TDI monomer. Three partial least squares models were created to evaluate the generator. The investigated responses were the TDI concentration, the particle number concentration, and the stability of the particle number concentration during the generating process. The factor with most impact on the concentrations of the generated aerosol was found to be the interaction between linear feeding rate of the polymer strip and the flow rate of combustion gas. For stability the linear feeding rate was the most important.

Aerosols↗

PubMed1979

Cyanide toxicity from the thermal degradation of rigid polyurethane foam.

Thermal degradation products (tdp) from a model, rigid polyurethane foam were collected in such a manner as to eliminate carbon monoxide and other gases with low boiling points. The effects in rats resulting from intratracheal intubation (I.T.) of the tdp are discussed. Cyanide was found to be a major factor associated with severe toxic responses of the experimental rats.

Animals↗

PubMed1981

Risk associated with the spray application of polyurethane foam.

The use of polyurethane foam in thermal insulation is increasing rapidly. In most cases, the raw products consist of toluene di-isocyanate or diphenyl methane di-isocyanate and a polyol curing agent. We studied the isocyanate exposure of workers applying the foam in confined spaces. Frequent excursions above safe limits were found with levels up to and exceeding 0.08 ppm for personal sampling and 0.148 for area sampling. Since improper devices were worn, this represented a significant risk to health.

Air Pollutants↗

PubMed1984

Airborne isocyanates in polyurethane spray painting: determination and respirator efficiency.

The concentrations of airborne isocyanates were measured during spray painting with two-component polyurethane paint. The isocyanate component - hexamethylene-diisocyanate (HDI) and its prepolymer of the biuret type - were determined by high performance liquid chromatography after derivatization to stable urea derivatives with N-4-nitrobenzyl-N-n-propylamine. Samples were collected on reagent impregnated glassfiber filters, and the derivatives were eluted with the chromatographic eluent. An impregnation technique is reported; it facilitates the chromatographic separation and the subsequent quantitative determination. Recovery studies from filters were performed in the range of 0.05 to 30 micrograms for the HDI monomer, and 0.5 to 100 micrograms for the HDI oligomer on the same filter. Average recoveries of the monomer and the oligomer were 97 +/- 2% (standard deviation) and 92 +/- 4%, respectively. The concentrations of the isocyanate components, measured during spray painting, were very high. For example, the level of the monomer frequently exceeded the hygienic limit value of 0.07 mg/m, set by the National Board of Labour Protection in Finland. As the concentrations of the HDI oligomer were at least one order of magnitude higher, appreciable exposure to isocyanate occurred if the respiratory protection was inadequate. The filter sampling technique made it possible to measure concentrations inside respirators.

Air Pollutants, Occupational↗

PubMed1984

Isomeric composition of airborne TDI in the polyurethane foam industry.

The isomeric composition of airborne toluene diisocyanate has been determined in two plants producing slab stock flexible polyurethane foam. The high performance liquid chromatographic technique used for analysis of the collected samples was optimized for the quantitative and qualitative determination of 2,4 and 2,6-TDI. The data indicates that there is a very large increase in the amount of airborne 2,6-TDI relative to the 2,4 isomer, as compared to the starting material used in the process. The magnitude of the increase was dependent on the stage of production. These results are consistent with the hypothesis of increased offgassing of 2,6-TDI, due to its lower reactivity.

Air Pollutants, Occupational↗

PubMed1987

Toluene diisocyanate exposures in the flexible polyurethane foam industry.

A 3-year survey of toluene diisocyanate exposure in two flexible polyurethane foam manufacturing facilities has been conducted. The geometric mean time-weighted average exposures were 2.36 ppb, 1.10 ppb, and 1.50 ppb for the foam line workers, finishing workers, and maintenance personnel, respectively. The OSHA ceiling standard of 20 ppb was exceeded by 1.3% of the short-term (12 min) exposure measurements taken. Exposures were shown to be predominantly to the 2,6 isomer of TDI.

Air Pollutants, Occupational↗

PubMed1989

Assessment of isocyanate exposure during the spray application of polyurethane foam.

This survey examined the air concentrations of diphenylmethane 4,4' diisocyanate (MDI) produced during the spray application of polyurethane foam at both indoor and outdoor locations. The sprayer, his helper(s), and fixed distances from the spray operation were sampled. The sprayers had the highest exposure levels, followed by outdoor helpers, then by indoor helpers. Area sample results showed that levels at a distance greater than 3 m (10 ft) outdoors and 8 m (25 ft) indoors were negligible, thereby supporting the establishment of a "work zone" around the spray operation.

Air Pollutants, Occupational↗

PubMed1993

A survey of airborne HDI, HDI-based polyisocyanate and solvent concentrations in the manufacture and application of polyurethane coatings.

This study summarizes the results of industrial hygiene surveys performed between 1979 and 1987 in paint manufacturing and application operations using polyurethane coatings containing hexamethylene diisocyanate (HDI) and HDI-based polyisocyanates (trade name Desmodur N). A total of 466 Desmodur N and 457 HDI samples were collected from 47 operations most of which were in application. The application surveys covered manufacture and refinishing of transportation vehicles, painting of large military and civilian equipment, industrial finishing operations, and maintenance and construction operations. The primary objective of the surveys was to assess the potential exposure to HDI and HDI-based polyisocyanate. In more than 60% of the surveys, concentrations of airborne organic solvents also were monitored. Isocyanates were sampled using toluene/nitroreagent in midget impingers, and solvents were collected using charcoal tubes. They were analyzed using high pressure liquid chromatography and gas chromatography, respectively. The data from these workplace situations show there is some potential for isocyanate overexposure of unprotected workers and that it is greater in spray than in nonspray operations.

Air Pollutants↗

PubMed2004

Polyurethane vascular grafts with thorough porosity: does an internal or an external membrane wrapping improve their in vivo blood compatibility and biofunctionality?

Using a freeze-drying multiple-step technique, porous polyurethane vascular grafts 1.5 mm in diameter with different internal and external surface characteristics were fabricated: Type A: with thorough porosity, Type B: with internal membrane wrapping and Type C: with external membrane wrapping. One centimeter long tubes of each three types of grafts were implanted into the infra-renal abdominal aorta of rats for periods of 2, 4, 8 weeks. All the grafts were patent at harvesting. At the end of 2 weeks postimplantation, the endothelial cells layer developed inside the grafts about 1.2 mm apart from either the distal anastomosis side or both the distal and proximal anastomoses. They spreaded to the middle part of the one cm-long graft at 4 weeks. The luminal surfaces were entirely covered by a layer of endothelial cells at 8 weeks. Smooth muscle cells also migrated underneath the endothelial cell layer through the inner surface from the anastomosis and grew into the porous wall to generate a biocomposite blood conduit. Type B grafts with an internal membrane wrapping, developed a thicker, easy to lift intima after all the durations of implantation because the internal capsule was poorly anchored to the device. It is therefore of paramount importance that a porous structure is exposed to the blood flow to permit an adequate healing together with a good anchorage of the internal capsule.

Animals↗

PubMed1999

Neutrophil chemotaxis on silicone and polyurethane surfaces.

Silicone vascular catheters have a greater risk of infection and produce greater inflammation in vivo and greater complement activation in vitro than other vascular catheter polymer materials. This study investigated whether polymorphonuclear leukocyte (PMNL) chemotaxis under agarose on silicone surfaces is different than on polyurethane (PU). Glass slides were coated with silicone and PU by use of a constant-speed dipping apparatus. Chemotaxis (3 h) in response to (10-7 mL) FMLP, zymosan-activated serum, and fresh serum (100%) was greater on silicone than on PU (P<.05). Polyclonal antibody to C5a blocked >50% of the movement toward serum (P<.05). Serum in the PMNL well significantly decreased chemotaxis toward FMLP on silicone (P<.05) but not on PU. These findings suggest that excessive complement activation by silicone may interfere with chemotaxis, but further work is necessary to determine whether this is relevant to an increased risk of catheter-related infection.

Blood↗