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At least 613 records · Page 34Linked to original sources
PubMed2006

Optimization of a thick polyvinyl alcohol-acrylamide photopolymer for data storage using a combination of angular and peristrophic holographic multiplexing.

The capability of polyvinyl alcohol-acrylamide photopolymer materials to obtain angularly multiplexed holographic gratings has been demonstrated [Appl. Phys. B 76, 851 (2003)]. A combination of two multiplexing methods--peristrophic and angular multiplexing--is used to record 60 holograms. An exposure schedule method is used to optimize the capability of the photopolymerizable holographic material and obtain holograms with a higher, more uniform diffraction efficiency. In addition, because of this exposure schedule method, the entire dynamic range (M#) of the material will be exploited, obtaining values of approximately M# approximately 9 in layers approximately 800 microm thick.

Journal Article↗
PubMed2003

Edge-enhanced imaging with polyvinyl alcohol/acrylamide photopolymer gratings.

We demonstrate edge-enhanced imaging produced by volume phase gratings recorded on a polyvinyl alcohol/acrylamide photopolymer. Bragg diffraction, exhibited by volume gratings, modifies the impulse response of the imaging system, facilitating spatial filtering operations with no need for a physical Fourier plane. We demonstrate that Kogelnik's coupled-wave theory can be used to calculate the transfer function for the transmitted and the diffracted orders. The experimental and simulated results agree, and they demonstrate the feasibility of our proposal.

Journal Article↗
PubMed1991

[Exposure of workers to electric and magnetic fields from radiofrequency dielectric heaters to process polyvinyl chloride material].

Exposure of workers to electric and magnetic fields from radiofrequency dielectric heaters (RF heaters) to process polyvinyl chloride material was surveyed. Measurements of electric and magnetic field strengths were made in 10 workers operating 7 RF heaters at 3 plants in Japan. Six of the RF heaters are of the sewing machine type and the other is of the shuttle tray type. In all the RF heaters surveyed the nominal frequency of the radiofrequency generator was 40 MHz, and therefore electric and magnetic field from these are assumed to oscillate at the same frequency. The power output ranged from 0.83 W to 1.8 W for the sewing machine type and was 2.4 W for this shuttle tray type. Measurements were made at about 5 cm from the surface of the hand, eye, chest, waist, knee and foot of each worker. The meter readings were converted to equivalent plane wave power density and corrected for duty cycle (0.073 to 0.27). It was found that all the workers surveyed were exposed to electric and magnetic field strengths greater than the TLV recommended by ACGIH (1 mW/cm2). For the hand, eye, chest, waist, knee and foot of the worker, 95%, 63%, 32%, 47% and 36% and 27% of the measured field strengths exceeded the TLV, respectively. Especially for the sewing machine type RF heaters, electric fields at the hand and eye were extremely strong. Thus, for the hand, 100%, 75% and 38% of the measured electric field strengths exceeded the TLV, ten times the TLV, and one hundred times the TLV, respectively, and for the eye, 88% and 25% exceeded the TLV and ten times the TLV, respectively. No correlation was observed between power output of the RF heaters and measured electric and magnetic field strengths at any anatomical site of the worker.

Chemical Industry↗
PubMed1991

Vinyl chloride related hepatic angiosarcoma in a polyvinyl chloride autoclave cleaner in Australia.

OBJECTIVE: To present the first case of vinyl chloride related hepatic angiosarcoma in Australia. CLINICAL FEATURES: A 51-year-old male caucasian former polyvinyl chloride autoclave cleaner in an Australian chemical plant developed hepatic angiosarcoma, presenting 15 years after his last exposure to vinyl chloride monomer. OUTCOME: He developed encephalopathy and died in oliguric renal failure 21 days after admission to hospital. CONCLUSION: Hepatic angiosarcoma may develop in other workers similarly exposed.

Australia↗
PubMed2001

Studies on gynaecological hydrophilic lactic acid preparations. Part 4: Effects of polyvinyl pyrrolidone K-90 on properties of methylcellulose gels.

In continuing the investigation of the binding of lactic acid with basic polymers polyvinyl pyrrolidone K-90 (PVP) was used. Use of PVP in mixtures with lactic acid in experimentally determined and calculated proportions allowed the preparation of gels with pH 3.8-4.4, i.e. maintaining the physiological conditions in the vagina. The viscosity of the methylcellulose gels increases proportionally to the amount of the PVP--lactic acid complex added. Examination of the gels in the biopharmaceutical model, which simulated the physiological conditions of the vagina, allowed determination of the mobility of the preparations in patients.

Gels↗
PubMedDate not supplied

Chitosan-polyvinyl pyrrolidone hydrogel does not activate macrophages: potentials for transplantation applications.

We have shown previously that chitosan-polyvinyl pyrrolidone (PVP) hydrogels are blood compatible, islet compatible, and noncytotoxic to various cell types. Because of these potential applications of chitosan-PVP hydrogel, the present study was designed to investigate its effect on macrophage activation. Macrophages did not adhere to hydrogel in culture but maintained their viability and did not undergo apoptosis as confirmed by trypan blue staining and absence of DNA ladder. Hydrogel leach-out products did not exhibit cytotoxic effects on macrophage functionality at mitochondrial and lysosomal level as confirmed by tetrazolium reduction (MTT) and neutral red uptake (NRU) assay. On exposure to hydrogels, macrophages showed comparable expression of activation markers such as CDllb/CD18 (Mac-1), CD45, and CD14 to those cultured in the presence of PTFE, a known biocompatible control, indicating its nonactivating nature. Macrophage activation was also assessed by checking the level of messenger RNA of inflammatory cytokines such as IL-6 and TNF-alpha by reverse transcriptase polymerase chain reaction (RT-PCR), which did not show stastistically significant difference (p > 0.05) in the expression of these transcripts in both control and hydrogel-exposed macrophages. The nonimmunogenic nature of the hydrogel was further confirmed by the lack of induced proliferation of mouse splenic lymphocytes after exposure to hydrogel leach-outs. All these results point out that chitosan-PVP hydrogel did not activate macrophages and thus is immunocompatible. Our results indicate that this hydrogel could be a potential candidate for transplantation studies by virtue of its biocompatibility and imunocompatibility.

Animals↗
PubMed1975

[Liver disease in polyvinyl chloride production workers - Clinical and peritoneoscopic aspects (author's transl)].

Peculiar clinical symptoms observed in polyvinyl chloride production workers of a nearby chemical plant arose the suspicion of liver and spleen disease in these workers before first reports on vinyl chloride-induced angiosarcoma of the liver became known. Starting at the end of 1972, 44 workers were followed up by biochemical investigations, peritoneoscopy and liver biopsy. As early as 1973 it could be ascertained, that advanced vinyl chloride-induced liver damage presents as hepatic fibrosis with splenomegaly, portal hypertension, and thrombocytopenia without conspicuous deterioration of hepatic parenchyma function. Similar symptoms have been observed after chronic intoxication by arsenic and thorium dioxide (thorotrast). The clinical and peritoneoscopic aspects of the disease are described.

Chemical Industry↗
PubMed2000

The effect of microwave heating on the acidity of 0.9% saline in 1 litre and 100 mL polyvinyl chloride packaging.

OBJECTIVE: Microwave warming of intravenous crystalloid solutions is an accepted practice in operating suites and emergency departments. These intravenous solutions are stored in polyvinyl chloride (PVC) and are known to be acidic. Some of this acidity may be from PVC packaging. We asked if microwave heating affected the acidity of 0.9% saline solution in 1 litre and 100 mL PVC bags. METHODS: Seven 1 litre bags were heated in an 800 Watt microwave for 2 minutes each and seven 100 mL bags were heated for 30 seconds each. After overnight cooling to room temperature, pH and temperature were measured and compared with two control groups of 7 unheated bags. RESULTS: There was no significant difference between the pH of heated and unheated solutions of saline. The median pH of the 1 litre bags were 5.01 (control) and 5.02 (heated). The median pH of the 100 mL bags were 4.58 (control) and 4.59 (heated). Post hoc, we found the 100 mL bags were more acidic than the 1 litre bags by a median difference of 0.43 pH units (P = 0.002). CONCLUSIONS: Microwave heating does not change the acidity of 0.9% saline in 1 litre or 100 mL PVC packaging.

Journal Article↗
PubMed1978

Responses to polyvinyl pyrrolidone and pneumococcal polysaccharide in protein-deficient mice.

Indirect haemagglutination titres induced by polyvinyl pyrrolidone (PVP) or pneumococcal polysaccharide Type III (S111) were determined in mice maintained on a 4% albumin diet from weaning and normally-fed littermates. Responses to PVP, given intravenously (i.v.) or intraperitoneally (i.p.), were elevated by protein-deficiency at low antigen doses and increasingly depressed at high doses. Increases in the duration of protein-deficiency generally improved these responses. The persistence of tolerance was reduced by protein-deficiency and priming was evident in both groups when tolerance was broken. The low protein diet depressed responses to moderate doses of S111 given i.p. to C57Bl mice, but such responses were normal in BALB/c mice and in C57Bl mice injected i.v. High doses of S111 (i.p., i.v.) elicited poor responses in deficient mice. These findings are discussed in relation to previous studies using other antigens, with a view to elucidating mechanisms responsible for the effects of protein-deficiency.

Animals↗
PubMed1978

[Mandibular localization of thesaurismosis (polyvinyl-pyrrolidine) (author's transl)].

The authors report on a case of isolated mandibular localization of polyvinyl-pyrrolidine thesaurismosis. The patient, a man of 38, had been treated with injections of posterior pituitary extract, for a period of eighteen months, 10 year ago. Localization in the mandible is extremely rare, making diagnosis difficult unless a detailed anamnesis is available.

Adult↗
PubMed1979

[Peritoneal irrigation and lavage using iodinated polyvinyl-pyrrolidone in acute generalized peritonitis (70 cases treated in an intensive care unit)].

The authors report 70 cases of severe acute generalise peritonitis treated during the immediate postoperative periode by peritoneal irrigation-lavage using iodinated polyvinyl-pyrrolidone for 16 days. All of the patients were hospitalised in an intensive care unit because of septicaemia, respiratory distress, acute renal failure, etc. After an aetiological study of these cases of peritonitis, the technique of installation and surveillance and the complications of peritoneal irrigation-lavage are analysed. The results in this series confirm the efficacy of the technique as long as it is used from the outset, immediately following the onset of peritonitis.

Acute Disease↗
PubMed1997

In vitro evaluation of flutamide-carrier systems. Part 1: Preparation and evaluation of flutamide systems with polyvinyl pyrrolidone and polyethylene glycol 4000 and 6000.

Coprecipitates were prepared using different ratios of flutamide with polyvinyl pyrrolidine (PVP), polyethylene glycol (PEG) 4000 and 6000. Drug solubility in carrier solutions, thin layer chromatography (TLC), differential scanning calorimetry (DSC), infra-red spectroscopy (IR), uniformity of drug content, drug dissolution from its respective systems and effect of aging on the physico-chemical parameters of stored flutamide-polymer system were studied. PEG 6000 was found to be the most efficient polymer in increasing both the solubility and the release rate of flutamide. Interaction was found to be complete in certain ratios of drug/polymer systems. The dissolution pattern of flutamide from all the prepared systems appeared to fit a first order mechanism. Physico-chemical parameters of flutamide/carrier systems were not influenced by storage.

Antineoplastic Agents, Hormonal↗
PubMed1976

The effect of amino acid restricted diets on the clearance of 125I-labelled polyvinyl pyrrolidone in mice.

Impaired overall phagocytic function, as measured by clearance of radio-labelled polyvinyl pyrrolidone from the blood (KPVP), has been demonstrated in mice whose dietary intake of the essential amino acids phenylalanine and tryptophan was reduced to less than a quarter of that in a standard diet which supported optimal growth. This was associated with loss in weight of body, liver, spleen and thymus and an increase in the phagocytic index, alphaPVP.

Amino Acids↗
PubMed1998

Interaction of sodium dehydrocholate and sodium cholate with polyvinyl pyrrolidone in aqueous medium.

The results of interaction of the bile salts sodium dehydrocholate (NaDHC) and sodium cholate (NaC) with the water soluble polymer polyvinyl pyrrolidone (PVP) studied by the methods of conductance, surface tension, viscosity and calorimetry are reported. Both of the bile salts exhibited PVP influenced self-aggregation. While NaC showed expected surface tension behaviour, NaDHC exhibited anomalous behaviour. The minimum interfacial area per molecule of the bile salt, the maximum interfacial adsorption, the free energy of micellization and the free energy of interfacial adsorption are presented for NaC. This information was not obtained for NaDHC because of its anomalous surface tension behaviour. The bile-salt-adhered PVP exhibited polyelectrolyte behaviour at PVP concentrations < 0.25 g dl-1. The enthalpy of interaction of NaC with PVP had a maximum at 0.25 mole dm-3 (delta Hi = +180 cal/mole); NaDHC produced too little heat to be detected by the calorimeter.

Cholic Acid↗