To investigate theological properties of common hydrophilic gel excipients such as Carbopol based on viscosity, the viscosity was determined by rotation method and falling-ball method. Linear regression was made between ln(eta) and concentration, the slope of which was used to explore the relation between viscosity and concentration of different excipients. The viscosity flow active energy (E(eta)) was calculated according to Arrhenius equation and was used to investigate the relation between viscosity and temperature of different excipients. The results showed that viscosities measured by two methods were consistent. Concentration of guargum (GG) and hydroxypropylmethyl cellulose (HPMC) solution had a great influence on the viscosity, k > 5; while concentration of polyvinylpyrrolidone-K30 (PVP-K30) and polyethylene glycol 6000 (PEG6000) exerted a less effect on viscosity, k < 0.2; viscosity flow active energy of different excipients were close, which ranged from 30 to 40 kJ x mol(-1). Therefore, theological properties study could provide the basis for application of excipients and establish a foundation for the research of relation between excipients structure, property and function.
Excipients ; chemistry ; Gels ; chemistry ; Polyethylene Glycols ; chemistry ; Polyvinyls ; chemistry ; Povidone ; chemistry ; Rheology ; Temperature ; Viscosity

To compare two enrichment and preservation methods of urinary proteins, stored in polyvinylidene difluoride (PVDF) membrane (Urimem) or direct freezing, we examined the differences between the two methods in time, space, costs of supplies and electricity, degree of protein degradation and convenience of the sample handling. The urimem method is superior in the storage space, the cost of electricity and the clinical convenience compared to the direct freezing method. However, the direct freezing method is superior in the time and the cost of supplies to the urimem method. The enrichment and preservation of urinary proteins using urimem have more cost-effective benefits compared to those of the direct freezing method.
Cost-Benefit Analysis ; Freezing ; Humans ; Polyvinyls ; Preservation, Biological ; methods ; Proteins ; chemistry ; Urine ; chemistry

OBJECTIVETo evaluate the dimensional stability and detail reproduction of five additional silicone impression materials after autoclave sterilization.

METHODSImpressions were made on the ISO 4823 standard mold containing several marking lines, in five kinds of additional silicone. All the impressions were sterilized by high temperature and pressure (135 °C, 212.8 kPa) for 25 min. Linear measurements of pre-sterilization and post-sterilization were made with a measuring microscope. Statistical analysis utilized single-factor analysis with pair-wise comparison of mean values when appropriate. Hypothesis testing was conducted at alpha = 0.05.

RESULTSNo significant difference was found between the pre-sterilization and post-sterilization conditions for all locations, and all the absolute valuse of linear rate of change less than 8%. All the sterilization by the autoclave did not affect the surfuce detail reproduction of the 5 impression materials.

CONCLUSIONSThe dimensional stability and detail reproduction of the five additional silicone impression materials in the study was unaffected by autoclave sterilization.

Dental Impression Materials ; chemistry ; Dental Models ; Hot Temperature ; Materials Testing ; Microscopy ; Polyvinyls ; chemistry ; Silicone Elastomers ; chemistry ; Siloxanes ; chemistry ; Sterilization ; methods

OBJECTIVETo compare the mechanical properties of different dental optimal material selection for orthodontic appliance.

METHODSFour commercialized thermoplastic products under different test conditions, and provide the suggestion of thermoplastic products were tested. The tear strength, elongation at break and stress relaxation of these materials were measured under different test conditions.

RESULTSThe tear strength declined after thermoforming, and rose again after 2 weeks of distilled water immersion. The elongation at break rose after thermoforming, and declined after 2 weeks of distilled water immersion. No significant changes were observed for brand A under different test conditions. Brand A showed the slowest stress relaxation of 0.0148 N/s.

CONCLUSIONSThe mechanical properties of thermoplastic materials were influenced by environmental factors. Brand A exhibited optimal comprehensive properties.

Analysis of Variance ; Dental Materials ; chemistry ; Hot Temperature ; Materials Testing ; Orthodontic Appliances ; Polyethylenes ; chemistry ; Polyvinyls ; chemistry ; Shear Strength ; Stress, Mechanical

AIMTo prepare dilitazem hydrochloride delayed-onset, sustained release tablet, which can not only provide the delay in release start, but also the constant release rate after a lag time. To analyze release mechanism and investigate the effect of outershell compositions on release behavior.

METHODSThe delayed-onset, sustained release tablets were prepared by dry-compression coated technology. The release profiles of uncoated cores and presscoated tablets were compared. Two parameters, time-lag (Tlag) and release rate (k), were used to evaluate the influence of factors, such as the amount of hydroxypropylmethylcellulose (HPMC) and poly-vinyl-pyrrolidinone (PVP) K30, the viscosity of ethylcellulose (EC) and HPMC, and the compression load on diltazam hydrochloride (DIL) release. Higuchi equation and Peppa's equation were used to analyze release mechanism.

RESULTSWith the increase of HPMC amount or HPMC viscosity, Tlag was prolonged and k was decreased; With the increase of PVP K30 amount, Tlag was shortened and k was increased; EC viscosity and compression load above certain degree showed no effect on DIL release.

CONCLUSIONThe drug release from delayed-release tablet is controlled by erosion mechanism, Tlag is determined by the erosion rate of outer-shell.

Cellulose ; chemistry ; Delayed-Action Preparations ; Diltiazem ; administration & dosage ; Lactose ; analogs & derivatives ; chemistry ; Methylcellulose ; analogs & derivatives ; chemistry ; Oxazines ; Polyvinyls ; chemistry ; Pyrrolidinones ; chemistry ; Tablets ; administration & dosage ; chemistry ; Technology, Pharmaceutical ; Viscosity

The low abundance and highly hydrophobic nature of most membrane proteins make their analysis more difficult than that for common soluble proteins. Successful membrane protein identification is largely dependent on the sample preparation including the enrichment and dissolution of the membrane proteins. A series of conventional and newly developed methods has been applied to the enrichment of low-abundance membrane proteins at membrane and/or protein levels and to the dissolution of hydrophobic membrane proteins. However, all the existing methods have inherent advantages and limitations. Up to now, there has been no unique method that can universally be employed to solve all the problems and more efforts are needed in improving sample preparation for the analysis of membrane proteomes.
Chromatography, High Pressure Liquid ; Mass Spectrometry ; Membrane Proteins ; analysis ; metabolism ; Membranes, Artificial ; Oxidation-Reduction ; Polyvinyls ; chemistry ; Proteome ; analysis ; Proteomics

High selectivity provided by biomolecules such as antibodies and enzymes has been exploited during the last two decades for development of biosensors. Of particular importance are efficient immobilization methods for biomolecules in order to preserve their biological activities. In this study, we have evaluated immobilization strategies for an anti-DNA antibody on a self-assembled monolayer of omega-functionalized thiols. The antibody was immobilized via peptide bond formation between the primary amines in the antibody and the carboxyl groups on the self-assembled monolayer. The peptide bond coupling was achieved by activating COOH groups on the surface through N-Hydroxysuccimide (NHS)-ester formation, followed by acylation of NH2 group in the antibody. DNA binding activity of the immobilized antibody was examined by counting beta emission from 35S-labeled DNA.
Antibodies, Antinuclear* ; DNA/immunology ; DNA/analysis* ; DNA-Binding Proteins/chemistry ; Gold ; Membranes, Artificial ; Polymerase Chain Reaction ; Polyvinyls/chemistry ; Radioimmunoassay/methods* ; Thioctic Acid/chemistry

OBJECTIVETo establish a three-dimensional digital dental model through scanning dental impression directly with micro-CT.

METHODSThe polyvinyl siloxane (PVS) impression of the plaster model was taken and scanned with micro-CT. VGStudio MAX and Imageware softwares were used to obtain the digital dental model.

RESULTSThe three-dimensional digital model was established successfully. The scanning layer was 90 µm.

CONCLUSIONSA new way of establishing the digital dental models could be achieved with micro-CT.

Computer-Aided Design ; Dental Impression Materials ; chemistry ; Dental Models ; Humans ; Image Processing, Computer-Assisted ; Imaging, Three-Dimensional ; Polyvinyls ; chemistry ; Siloxanes ; chemistry ; Software ; X-Ray Microtomography ; methods

In order to develop questionnaire estimating vinyl chloride monomer(VCM) exposure levels, to reset selection criteria for detailed tests, to measure current VCM exposure levels, to evaluate the mutagenic effects of VCM exposures and to develop multiphasic screening method of PVC- or VCM-handling workers, VCM concentrations of work environments were measured and tentative self-administrative questionnaire, physical examination, sister chromatid exchange(SCE) test and some clinical chemical test were applied to 195 men who had been handling VCM or PVC(Exposed Group) and 37, in the same factories without exposure to VCM or in polyethylene- or polypropylene-related factories(Control Group). Mean VCM concentrations of work environments were 0.268+/-0.183 ppm under PVC synthesis processes, 0.160+/-0.200 ppm under VCM synthesis process, 0.076+/-0.111 ppm under PVC pipe producing processes, 0.090+/-0.108 ppm under PVC wall paper, sheet, or film producing processes, 0.071+/-0.051 ppm under PVC floor producing processes, 0.243+/-0.250 ppm under PVC sash producing processes, and 0.020+/-0.031 ppm under triming process. VCM levels of work environments under manual resin mixing processes (0.209+/-0.168 ppm)were higher than those of the others (0.209+/-0.168 ppm) (p-value<0.05). There was no VCM-related symptoms, the positive response rates of which were higher in the Exposed Group. Overall abnormal rate in clinical chemistry test of the Exposed Group was higher than that of the Control Group, but due to extermely low exposure level of exposure group and to small sample size of the Control Group, no statistical significance was found(p-value>0.05). SCE frequencies of the Exposed Group were significantly higher than those of Contorl Group(p-value<0.05) and those of test-abnormal persons were higher than those of test-normal persons. SCE frequencies linearly increased with not only current but also cumulative VCM exposure levels(p-value<0.05). These results suggest that adverse health effect may ensue from VCM exposure to as low as 1 ppm. But SCE frequencies had no statistically significant correlation with drinking amounts, smoking amoutns, or radiation dose equivalents. Questionnaire was revised by referring to these results and formula estimating cumulative VCM exposure levels based on occupational history in questionnaire were made. In addition, were presented methods evaluating work environments and multiphasic screening test for PVC workers.
Chromatids ; Clinical Chemistry Tests ; Drinking ; Humans ; Male ; Multiphasic Screening* ; Patient Selection ; Physical Examination ; Polyvinyl Chloride* ; Polyvinyls* ; Questionnaires ; Sample Size ; Siblings ; Sister Chromatid Exchange ; Smoke ; Smoking ; Vinyl Chloride*

OBJECTIVESTo explore the forensic application value of MPure-12 automatic nucleic acid purification （MPure-12 Method） for DNA extraction by extracting and typing DNA from bloodstains and various kinds of biological samples with different DNA contents.

METHODSNine types of biological samples, such as bloodstains, semen stains, and saliva were collected. DNA were extracted using MPure-12 method and Chelex-100 method, followed by PCR amplification and electrophoresis for obtaining STR-profiles.

RESULTSThe samples such as hair root, chutty, butt, muscular tissue, saliva stain, bloodstain and semen stain were typed successfully by MPure-12 method. Partial alleles were lacked in the samples of saliva, and the genotyping of contact swabs was unsatisfactory. Additional, all of the bloodstains （20 μL, 15 μL, 10 μL, 5 μL, 1 μL） showed good typing results using Chelex-100 method. But the loss of alleles occurred in 1 μL blood volume by MPure-12 method.

CONCLUSIONSMPure-12 method is suitable for DNA extraction of a certain concentration blood samples．Chelex-100 method may be better for the extraction of trace blood samples．This instrument used in nucleic acid extraction has the advantages of simplicity of operator, rapidity, high extraction efficiency, high rate of reportable STR-profiles and lower man-made pollution.

Alleles ; Blood Stains ; Chelating Agents ; DNA/isolation & purification* ; DNA Fingerprinting ; Forensic Medicine/methods* ; Genotype ; Humans ; Male ; Polymerase Chain Reaction/methods* ; Polystyrenes ; Polyvinyls ; Resins, Synthetic ; Saliva ; Semen/chemistry*