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PubMedDate not supplied

Air-filled polymeric microcapsules from emulsions containing different organic phases.

Air-filled polymeric microcapsules for use as a contrast agent in ultrasonography have been prepared by the freeze-drying of different oil-in-water emulsions. The water phases consisted of a block copolymer in water. The organic phases consisted of a biodegradable polyester dissolved in (-)-camphene, cyclooctane, cyclohexane or tricyclene, which were relatively poor solvents for the polyester. A polymeric wall was, therefore, precipitated at the droplet surface early in the process, i.e. during freezing. Removing the solvent during freeze-drying, resulted in air-filled microcapsules. The microcapsules were suspended in saline after freeze-drying. All the suspensions contained echogenic microcapsules with a volume mean diameter of approximately 5-7 microm. Microscopic investigations showed that the microcapsules were spherical and hollow. Tricyclene and, to some degree, (-)-camphene were found unsuitable for industrial production due to melting points above 30 degrees C. Cyclooctane and cyclohexane were investigated as replacements for the initially chosen (-)-camphene, since they are liquids over a wider temperature range. These solvents gave improved yields, measured both as particle volume concentration per amount of polymer in suspension and acoustic attenuation at 3.5 MHz per amount of polymer in suspension, although the freeze-drying cycle was not optimized for these systems.

Air↗

PubMedDate not supplied

A review of plastic waste biodegradation.

With more and more plastics being employed in human lives and increasing pressure being placed on capacities available for plastic waste disposal, the need for biodegradable plastics and biodegradation of plastic wastes has assumed increasing importance in the last few years. This review looks at the technological advancement made in the development of more easily biodegradable plastics and the biodegradation of conventional plastics by microorganisms. Additives, such as pro-oxidants and starch, are applied in synthetic materials to modify and make plastics biodegradable. Recent research has shown that thermoplastics derived from polyolefins, traditionally considered resistant to biodegradation in ambient environment, are biodegraded following photo-degradation and chemical degradation. Thermoset plastics, such as aliphatic polyester and polyester polyurethane, are easily attacked by microorganisms directly because of the potential hydrolytic cleavage of ester or urethane bonds in their structures. Some microorganisms have been isolated to utilize polyurethane as a sole source of carbon and nitrogen source. Aliphatic-aromatic copolyesters have active commercial applications because of their good mechanical properties and biodegradability. Reviewing published and ongoing studies on plastic biodegradation, this paper attempts to make conclusions on potentially viable methods to reduce impacts of plastic waste on the environment.

Bacteria↗

PubMedDate not supplied

A model of suture-induced urolithiasis with urographic control in the bladder of the rat.

The characteristics of a model of urolithiasis in the bladder of male Wistar rats were evaluated. Two techniques were compared: one knot of suture material through the bladder wall, or 15-throw knots inside the bladder. Rats were randomly assigned to one of six groups, according to the technique and suture material used (polyester, silk, or chromic catgut). An excretory urogram was performed at days 30, 60, and 90. At the moment of positive radiographic diagnosis, animals were sacrificed and stones were obtained. All rats were sacrificed at day 90 regardless of the x-ray results. Variables evaluated were average days to a positive urogram, average weight of all uroliths, and percentage of animals developing urolithiasis throughout the study. There were no statistical differences between groups for the average weight of stones, which ranged from 0.008 to 1.502 g for individual cases. All three materials were more lithogenic with the 15-throw knot inside technique. No significant differences were detected for lithogenesis criteria between suture materials. X-ray dispersion spectroscopy evidenced calcium phosphate composition of two stones from chromic catgut, and magnesium phosphate composition of two stones from chromic catgut, two from silk, and two from polyester. Neo-epithelization over the suture was confirmed microscopically in bladders with the one-throw technique. We conclude that (1) this is an effective model of urolithiasis, with predictability in time, composition, and amount of stone formation; (2) the presence of more suture material inside the bladder is more lithogenic; and (3) excretory urograms are highly sensitive and specific for the noninvasive diagnosis of bladder urolithiasis.

Animals↗

PubMed2002

Fabric-staining properties and washability of a novel liposomal dithranol formulation.

AIM: To test the staining potential of a novel liposomal dithranol gel on different types of fabrics and compare it with the only commercially available dithranol preparation in India, Derobin. METHODS: Pure cotton, pure polyester and four blends of the two fabrics were tested for staining and washability. RESULTS: Both products showed the least staining and spreading on pure cotton with progressively worse stains as the proportion of polyester in the fabric increased. When compared with each other the liposomal dithranol gel showed markedly lighter staining than Derobin on all fabrics. It also washed off completely with water whereas the Derobin stains could not be washed off, even with detergent. CONCLUSION: The liposomal gel due to its superior staining properties may potentially increase the acceptability of dithranol amongst psoriasis patients.

Administration, Topical↗

PubMed1998

A Comparison of Skin Temperatures and Clothing Microclimate During Moderate Intermittent Exercise in the Cold Between One and Two Layers of Cotton and Polypropylene Underwear.

The purpose of this study was to compare the effects of 2 kinds of underwear made from hydrophobic and hydrophilic fabrics on the mean skin temperatures and clothing microclimate (temperature, humidity) in participants performing intermittent exercise in cold environmental conditions. One or 2 layers of cotton underwear (C1, C2) with a 2-piece long-sleeved shirt and long-legged trousers, and 1 or 2 layers of polypropylene underwear (P1, P2) with a 2-piece long-sleeved shirt and long-legged trousers were used as experimental underwear. In addition, the participants wore a 2-piece ski suit as 100% polyester clothing including 100% polyester padding. Ten young adult females volunteered as participants. The experiments were performed in a climatic chamber at an ambient temperature (Ta) of 0°C and an air velocity of 0.26 m s-1. The major findings are summarized as follows: (a) Although the clothing microclimate humidity was not different within the ski suit of outer clothing between C1 and P1, it was significantly higher in P2 than in C2; (b) Clothing microclimate temperature inside the ski suit did not differ between C1 and P1, whereas it was significantly higher in P2 than in C2; (c) The thermal gradient between innermost and outermost of clothing microclimate at back level did not show any difference between C1 and P1, but it was significantly higher in C2 than in P2. These results are discussed in terms of thermal physiology and clothing sciences.

clothing microclimate↗

PubMed2006

Decomposition of 1,4-dioxane by advanced oxidation and biochemical process.

This study was undertaken to determine the optimal decomposition conditions when 1,4-dioxane was degraded using either the AOPs (Advanced Oxidation Processes) or the BAC-TERRA microbial complex. The advanced oxidation was operated with H2O2, in the range 4.7 to 51 mM, under 254 nm (25 W lamp) illumination, while varying the reaction parameters, such as the air flow rate and reaction time. The greatest oxidation rate (96%) of 1,4-dioxane was achieved with H2O2 concentration of 17 mM after a 2-hr reaction. As a result of this reaction, organic acid intermediates were formed, such as acetic, propionic and butyric acids. Furthermore, the study revealed that suspended particles, i.e., bio-flocs, kaolin and pozzolan, in the reaction were able to have an impact on the extent of 1,4-dioxane decomposition. The decomposition of 1,4-dioxane in the presence of bio-flocs was significantly declined due to hindered UV penetration through the solution as a result of the consistent dispersion of bio-particles. In contrast, dosing with pozzolan decomposed up to 98.8% of the 1,4-dioxane after 2 hr of reaction. Two actual wastewaters, from polyester manufacturing, containing 1,4-dioxane in the range 370 to 450 mg/L were able to be oxidized by as high as 100% within 15 min with the introduction of 100:200 (mg/L) Fe(II):H202 under UV illumination. Aerobic biological decomposition, employing BAC-TERRA, was able to remove up to 90% of 1,4-dioxane after 15 days of incubation. In the meantime, the by-products (i.e., acetic, propionic and valeric acid) generated were similar to those formed during the AOPs investigation. According to kinetic studies, both photo-decomposition and biodegradation of 1,4-dioxane followed pseudo first-order reaction kinetics, with k = 5 x 10(-4) s(-1) and 2.38 x 10(-6) s(-1), respectively. It was concluded that 1,4-dioxane could be readily degraded by both AOPs and BAC-TERRA, and that the actual polyester wastewater containing 1,4-dioxane could be successfully decomposed under the conditions of photo-Fenton oxidation.

Biochemical Phenomena↗

PubMed2006

Evaluation of coagulation-flocculation on a COD-based molecular size distribution for a textile finishing mill effluent.

The chemical treatability of wastewaters generated from a textile manufacturing plant performing wool, polyester, wool-polyester blends, woven fabric as well as yarn dyeing and finishing operations was investigated. Coagulation and flocculation experiments were conducted with alum, sodium bentonite and iron salts on wastewaters collected from both the fabric finishing line, after being subjected to in-plant control measures covering water conservation practices and segregation of reusable streams, and dyeing line. The effect of optimum treatment alternatives on the chemical oxygen demand (COD) values of different molecular weight cut-off fractions was also examined.

Alum Compounds↗

PubMed2005

C-reactive protein concentration in vaginal fluid as a marker for intra-amniotic inflammation/infection in preterm premature rupture of membranes.

OBJECTIVE: The purpose of this study was to determine whether C-reactive protein (CRP) concentrations in vaginal fluid can identify patients with intra-amniotic inflammation/infection (IAI) and predict adverse outcome in preterm premature rupture of membranes (PROM). METHODS: The study population consisted of 121 singleton pregnant women with preterm PROM (36 weeks of gestation) who had an amniocentesis and vaginal fluid collection. A Dacron polyester-tipped applicator was soaked with vaginal fluid for 10 seconds and diluted with 1 mL buffer solution. Amniotic fluid was cultured for aerobic and anaerobic bacteria, as well as mycoplasmas. Vaginal fluid CRP and amniotic fluid matrix metalloproteinase-8 (MMP-8) were determined by specific immunoassays. IAI was defined as an amniotic fluid MMP-8 concentration >23 ng/mL and/or a positive amniotic fluid culture. Nonparametric tests and survival techniques were used for statistical analysis. RESULTS: Patients with IAI had a significantly higher median vaginal fluid CRP concentration than those without IAI (median (range), 7.8 (0.1-1310.1) ng/mL vs. 1.0 (0.1-319.4) ng/mL, p < 0.005). The median amniotic fluid white blood cell (WBC) count was significantly higher in patients with a vaginal fluid CRP concentration of >10 ng/mL than in those with a lower concentration (median (range), 82.5 (0-8640) cells/mm3 vs. 2 (0->1000) cells/mm3, p < 0.001). Patients with vaginal fluid CRP concentration of >10 ng/mL had a significantly shorter sampling-to-delivery interval and higher rates of preterm delivery within five days, funisitis, and histologic chorioamnionitis than did those with a vaginal fluid CRP concentration below this cut-off. A vaginal fluid CRP cut-off of 10 ng/mL had a specificity of 89% and a sensitivity of 45% in the identification of IAI. CONCLUSION: An elevated CRP concentration in vaginal fluid collected by polyester-tipped applicator is a risk factor for intra-amniotic inflammation/infection and impending preterm delivery in preterm PROM.

Amniocentesis↗

PubMed1994

Dyed particle capture immunoassay for detection of incipient brown-rot decay.

An immunological method for detecting incipient fungal decay in wood is described. Monoclonal antibody to extracellular beta-1,4-xylanase of the brown-rot fungus Postia placenta was immobilized in a defined capture zone to a strip of hydrophobic polyester cloth. Polyclonal-labeled latex particles were applied near one end of the polyester assay substrate. The resulting test strip was dipped into extracts from wood blocks inoculated with various wood decay fungi. Extracts flowed laterally through the antibody-labeled latex particles and the capture zone. When antigen was present in the extract, the antigen was complexed by the monoclonal and labeled-polyclonal antibodies to form an observable particle complex in the zone of capture. Wood samples were tested at various stages of decay and correlated with wood weight loss. Incipient brown-rot decay was detected with the particle capture immunoassay at less than 2 percent wood weight loss.

Antibodies, Fungal↗

PubMed1975

Improved resolution of natural diacylglycerols by gas-liquid chromatography on polar siloxanes.

A new cyanoalkylphenylsiloxane (SILAR 5CP) liquid phase is shown to possess sufficient polarity to permit improved GC separations of natural diacylglycerols based on unsaturation and positional placement of fatty acids as well as on molecular weight, which was previously possible only on ethylene glycol succinate polyesters. Unlike the polyesters, the polar siloxane polymer has moderate thermal stability and provides GC columns which can be used for several months without replacing the packing. The GC analyses were made with conventional columns containing 3% SILAR 5CP on Gas Chrom Q at 270 degrees C isothermally. The diacylglycerols were chromatographed as the TMS ethers. Excellent seperations were obtained for the 1,2(2,3)- and 1,3-diacyglycerols derived from corn, linseed, peanut and cod liver oils and for the 1,2-diacyl-sn-glycerols from hepatic glycerophospholipids.

Animals↗

PubMed1997

Growth, leaf anatomy, and physiology of Populus clones in response to solar ultraviolet-B radiation.

We compared the physiological and morphological responses of rooted cuttings of Populus trichocarpa Torr. & Gray and P. trichocarpa x P. deltoides Bartr. ex Marsh. grown in either near-ambient solar ultraviolet-B (UV-B; 280-320 nm) radiation (cellulose diacetate film) or subambient UV-B radiation (polyester film) for one growing season. Midday biologically effective UV-B radiation was 120.6 and 1.6 mJ m(-2) s(-1) under the cellulose diacetate and polyester films, respectively. Gas exchange, leaf chlorophyll, light harvesting efficiency of photosystem II, and foliar UV-B radiation-absorbing compounds (i.e., flavonoid derivatives) were measured in expanding (leaf plastochron index (LPI) 5), nearly expanded (LPI 10), and fully expanded mature (LPI 15) leaves of intact plants of plastochron index 30 to 35. Plants were then harvested and height, diameter, biomass allocation and leaf anatomical attributes determined. Net photosynthesis, transpiration, and stomatal conductance were significantly greater in mature leaves exposed to subambient UV-B radiation than in mature leaves exposed to near-ambient UV-B radiation. Concentrations of UV-B radiation-absorbing compounds (measured as absorbance of methanol-extracts at 300 nm) were significantly greater in mature leaves exposed to near-ambient UV-B radiation than in mature leaves exposed to subambient UV-B radiation. The UV-B radiation treatments had no effects on chlorophyll content or intrinsic light harvesting efficiency of photosystem II. Height, diameter, and biomass were not significantly affected by UV-B radiation regime in either clone. Leaf anatomical development was unaffected by UV-B radiation treatment in P. trichocarpa x P. deltoides. For P. trichocarpa, leaf anatomical development was complete by LPI 10 in the near-ambient UV-B radiation treatment, but continued through to LPI 15 in the subambient UV-B radiation treatment. Mature leaves of P. trichocarpa were thicker in the subambient UV-B radiation treatment than in the near-ambient UV-B radiation treament as a result of greater development of palisade parenchyma tissue. We conclude that exposure to near-ambient UV-B radiation for one growing season caused shifts in carbon allocation from leaf development to other pools, probably including but not limited to, UV-B absorbing compounds. This reallocation curtailed leaf development and reduced photosynthetic capacity of the plants compared with those in the subambient UV-B radiation treatment and may affect growth over longer periods of exposure.

Journal Article↗

PubMed2004

Laser ignition of surgical drape materials in air, 50% oxygen, and 95% oxygen.

BACKGROUND: Operating room fires fueled by surgical drapes and ignited by high-energy surgical tools in air and oxygen-enriched atmospheres continue to occur. METHODS: The authors examined the time to ignition of huck towels and three commonly used surgical drape materials in air, 50% oxygen, and 95% oxygen using a carbon dioxide surgical laser as an ignition source. In addition, a phenol-polymer fabric was tested. RESULTS: In air, polypropylene and phenol polymer do not ignite. For polypropylene, the laser instantly vaporized a hole, and therefore, interaction between the laser and material ceased. When tested in combination with another material, the polypropylene time to ignition assumed the behavior of the material with which it was combined. For phenol polymer, the laser did not penetrate the material. Huck towels, cotton-polyester, and non-woven cellulose-polyester ignited in air with decreasing times to ignition. All tested materials ignited in 50% and 95% oxygen. CONCLUSION: The results of this study reveal that with increasing oxygen concentration, the time to ignition becomes shorter, and the consequences become more severe. The possibility exists for manufacturers to develop drape materials that are safer than existing materials.

Bedding and Linens↗

PubMed1976

Successful arterial substitution with modified human umbilical vein.

Human umbilical veins were prepared as vascular grafts by tanning with dialdehyde starch or gluteraldehyde and by structural re-inforcement with an outer polyester fiber mesh. These grafts were implanted in baboons in the aortoiliac position for periods of 3 days to 9 months. There was no aneurysm formation and there was an excellent maintenance of patency as well as function. Histologic evaluation of the graft materials showed a dense collagen layer within the encircling polyester fiber mesh. A multicellular subintimal layer formed a discrete inner capsule. The inflammatory response with the umbilical component was insignificant. There was no evidence of rejection. This study suggests that the modified umbilical vein can serve as a satisfactory blood conduit. Experience with three short-term clinical implants supports the applicability and potential for this new vascular graft.

Animals↗

PubMedDate not supplied

Long-term evaluation of a growable graft.

The safety of a vascular graft that can grow with the growth of its recipients was evaluated during long-term implantation in experimental animals. An acellular matrix made of human saphenous vein was cross-linked with a polyepoxy compound to give controlled biodegradability, hydrophilicity, and antithrombogenic properties. Four millimeter internal diameter (ID) grafts, enveloped with a polyester mesh tube of 10 mm ID were implanted in 15 puppies. The diameter of the graft grew to 9.5 mm after 1 year from the original 4 mm, and remained stable for 2 years and 7 months of observation. The newly formed neointima reinforced with polyester mesh was composed of smooth muscle cells covered with endothelial cells. The original vein graft was completely absorbed, and there were no degenerative changes such as calcification or aneurysmal dilatation. The graft maintained the expected size.

Animals↗

PubMedDate not supplied

Development of a vascular prosthesis for a growing child. A graft expandable in vivo.

Specially designed vascular prostheses that can be dilated after implantation using a percutaneous transluminal angioplasty (PTA) balloon catheter have been developed. The grafts are made of woven polyester fiber fabrics, the circumferential yarns of which consist of two different types of polyester fiber bundles: One is a straight weak bundle, the other is a strong bundle wound around the former. The graft with an initial diameter of 6 mm could be dilated to 9 mm by luminal inflation of the balloon four to five times at 10 atmospheres (atm) in vitro. After disrupting the weak bundle by the dilatation procedure, the strong bundles were straightened, which maintained the enlarged diameter of the new caliber. Grafts of 6 mm in initial diameter implanted into the thoracic aortas of mongrel dogs for 3 months also could be dilated in vivo by inflating the PTA four to five times at 15 atm, as found in the vitro study. Macroscopic observation revealed that, around the dilated grafts, only a tiny hematoma was formed and nominal subsequent bleeding was observed, which indicated that the dilatation procedure was performed safely. The graft, which enables adaptation of the hydrodynamic property of the graft to the increased blood flow by PTA after implantation, is applicable in a growing child.

Angioplasty, Balloon↗

PubMedDate not supplied

The effect of smoke inhalation on bradykinin metabolism by the perfused and ventilated rat lung.

The effect of smoke inhalation on bradykinin metabolism was studied in the rat lung perfused with Ringer's bicarbonate solution. After smoke (from cotton, polyester, or seat cushion material) inhalation, tritium-labeled bradykinin was added to the Ringer's bicarbonate solution, and then the lung perfusion effluent aliquots containing bradykinin and its metabolic fragments were collected after a single transpulmonary passage. For the 20 control rats without smoke inhalation, 91% of the bradykinin dose was metabolized, with Pro-Pro (I), 49%, and Arg-Pro-Pro-Gly-Phe (II), 32%, being the predominant bradykinin cleavage fragments. For 12 rats with smoke inhalation, 89% of the bradykinin dose was metabolized, with I (28%) and II (36%) being the major bradykinin cleavage fragments. The type of smoke did not significantly alter the capacity of the rat lung to metabolize bradykinin. Exposure to smoke from seat cushion material for more than 3 minutes caused pulmonary edema and thickening, and smoke exposure for more than 5 minutes caused loss of integrity at the lung alveolar-capillary interface. In contrast, exposure to cotton or polyester smoke did not cause any observable gross changes of the lung. Electron microscopic examination of lung exposed to seat cushion material smoke revealed considerable damage, with the type I epithelium existing as patches on the alveolar surface and capillary endothelium separated from the basement lamina. Thus in our model acute, short-term inhalation of smoke did not significantly alter the amount of bradykinin metabolized by the pulmonary endothelium so long as the integrity of the lung alveolar-capillary interface was maintained, although there seemed to be a moderate shift in the amount of major cleavage fragments from I to II.

Animals↗

PubMedDate not supplied

The 1999 Lindberg award. 3% hydrogen peroxide for the gram-positive disinfection of fabrics.

Because of growing concern about the spread of antibiotic-resistant gram-positive bacteria in burn and trauma units, an inexpensive, safe, effective means of spot-disinfecting fabrics (such as privacy curtains) that remain in clinic or patient rooms as various patients use the rooms was sought. From comparisons of cost and safety data, 3% hydrogen peroxide was chosen to be tested for its efficacy in the control of these bacteria. Systematic laboratory testing used 30 antibiotic-resistant and sensitive staphylococci and enterococci and 4 common hospital fabrics: cotton (clothing), terry cloth (towels), cotton-polyester blend (scrub suits), and polyester (curtains). Without disinfection, bacteria survived for many hours to several days. After a single spraying with 3% hydrogen peroxide, all bacteria on all fabrics were dead within 5 to 120 minutes. On-site testing targeted privacy curtains in patients' rooms. Curtain edges that tended to be grabbed when moving the curtain showed a mixture of gram-positive and gram-negative bacteria (median, 22 bacteria/24 cm2). After these areas were sprayed with 3% hydrogen peroxide, no bacteria were found. It was concluded that spraying with 3% hydrogen peroxide is a safe, inexpensive, effective means of spot-disinfecting fabrics in patients' rooms; this simple procedure may limit the spread of potentially pathogenic antibiotic-resistant bacteria.

Aerosols↗

PubMedDate not supplied

A survey of gram-negative bacteria survival on hospital fabrics and plastics.

One critical factor for the transmission of microorganisms from person to person or from the environment to a person (patient or health care worker) is the ability of the microbe to survive on an environmental surface. The purpose of this study was to determine the length of survival of various gram-negative bacteria on fabrics and plastics commonly used in hospitals. Seven materials were tested: smooth cotton (clothing), cotton terry (towels), 60% cotton-40% polyester blend (scrub suits and lab coats), polyester (drapes), 75% nylon-25% spandex (pressure garments), polyvinyl (splash aprons), and polyurethane (keyboard covers). The following bacteria were tested: Pseudomonas aeruginosa, Escherichia coli, Klebsiella pneumoniae, Serratia marcescens, Proteus mirabilis, Acinetobacter species, and Enterobacter species. Swatches of the materials were inoculated with defined amounts of bacteria and assayed at regular intervals. Survival was dependent on the bacterium, its inoculum size, and the material tested. At 102 microorganisms per swatch, bacteria survived from less than 1 hour to 8 days. At 10(4) to 10(5) bacteria per swatch, survival ranged from 2 hours to more than 60 days. These findings emphasize the need for careful disinfection and conscientious contact control procedures in areas that serve immunosuppressed individuals, such as patients with burn injuries.

Bedding and Linens↗