Polyvinyl Chloride Strips Research Articles

A fiber Bragg grating-based smart wearable belt for monitoring knee joint postures

Smart wearable technology is exceedingly desirable in athletic sports due to being lightweight, flexible to bend, soft and comfortable. It can continuously deliver accurate information and deformation. During knee flexion, the upper knee perimeter increases with the shrinkage of the knee joint flexor, and it can be monitored. In this study, a fiber Bragg grating (FBG) smart belt is fabricated by embedding FBG sensors at the center of a special silica gel (with unique adhering characteristics to fix FBG on the surface of the belt) for sensing knee joint movements. Polyvinyl chloride strips were adhered to the surface of the smart wearable belt for better protection. The smart belt was calibrated in the laboratory by a systematical changing knee posture and used to identify body postures at various static and kinematic postures of a male subject. The FBG-based smart wearable belt presented a consistent wavelength change after each step by angle changes at the knee joint position. The wavelength increment of FBG sensors increases linearly with the increasing of the bend angle of the knee joint in static tests, and the related slope ratio was 0.3 nm/°. In a jogging test, the measurement sensitivity achieved by the FBG smart wearable belt was within a range between 0.018/° and 0.021 nm/° for the male subject at the velocities of 2 and 3 km/h, respectively. The smart wearable belt could be a useful index to characterize a simple design and ease of implementation, and could also applied for knee posture circumferential strain measurements, especially for sports activities and monitoring stroke patients. This FBG smart belt can be fabricated to produce smart sensing fabrics.

Simulation and Experimental Characterization of Lateral Imaging Resolution of Ultrasound Systems and Assessment of System Suitability for Acoustic Optic Nerve Sheath Diameter Measurement.

Optic nerve sheath diameter (ONSD) is used for the estimation of intracranial pressure (ICP). But there are still doubts about the quality of the images and the lateral resolution. Our aim is to investigate the system suitability and best lateral resolution of different ultrasound systems for acoustic ONSD measurement. First, we calculated the theoretically lateral imaging resolution at increasing frequencies: 6.6, 10, and 15 MHz using two different ultrasound systems. Second, we created two phantoms consisting of copper wires or polyvinylchloride (PVC) strips and tested the best lateral resolution at different frequencies with the two ultrasound systems. Using the same ultrasound systems, we evaluated the anatomy of optic nerve at increasing transmission frequencies. Finally, the two probes were tested in two patients with different neurological conditions affected by an increase of ICP. Theoretical resolutions were .63, .43, and .41 mm, respectively, with a frequency of 6.6, 10, and 15 MHz. We found a similar lateral resolution in both phantoms: copper wire; .56 mm at 6.6 MHz, .46 mm at 10 MHz, and .44 mm at 15 MHz; and PVC strips .6 mm at 6.6 MHz, .47 mm at 10 MHz, and .40 mm at 15 MHz in accordance with experimental resolution. The ONSD thickening could be clearly displayed at frequencies higher than 7.5 MHz using the two linear probes and the two patients with an increase of ICP showed thickening of ONSD. According to our study, both systems are suitable for ultrasound OSND measurement.

Co-immobilization of cholesterol esterase, cholesterol oxidase and peroxidase on PVC strip for serum cholesterol determination

A mixture of commercial cholesterol esterase, cholesterol oxidase and peroxidase was co-immobilized covalently on the surface of a polyvinyl chloride (PVC) sheet (plastic strip) after its chemical modification. The strip retained 75.23% of its initial activity of enzymes with a conjugation yield of 0.37 mg protein cm−2. The strip bound enzymes showed optimum activity at pH 7.2, when incubated at 45 °C for 5 min. The strip was employed for determination of total cholesterol in serum. Minimum detection limit of the method was 0.01 mM in serum. Analytical recovery of added cholesterol in serum (100 mg dL−1 and 200 mg dL−1) was 92.50% and 93.33% respectively. Within and between assays coefficients of variation (CVs) were 1.85% and 2.04% respectively. A good correlation (r = 0.998) was obtained between serum cholesterol values by standard enzymic colorimetric method and the present method. The strip was reused 200-times over a period of 4 months, when stored at 4 °C. The method has the advantage that it provides the reuse of enzymes with enormous ease. Overall results also strengthen our view of using a chemically modified plastic strip as a solid support for covalent immobilization of enzymes.

Adherence ability of Candida africana: a comparative study with Candida albicans and Candida dubliniensis

In this study, we compared the adherence ability to human Hela cells and biofilm formation of three closely related Candida yeast. In our experiments, Candida africana showed poor adhesion ability to human Hela cells and the absence of biofilm formation on polyvinyl chloride strips. Conversely, Candida albicans and Candida dubliniensis formed mature biofilms and stable attachment to Hela cells. To our knowledge, this is the first comparative study reporting data on biofilm formation and adherence to human Hela cells by C. africana.

Persistence and effectiveness of pyrethroids in plastic strips against Varroa jacobsoni (Acari: Varroidae) and mite resistance in a Mediterranean area.

An apiary trial was conducted in 1997 in Sardinia, Italy, to verify the effectiveness of fluvalinate in polyvinyl chloride strips and flumethrin in polyethylene strips against Varroa jacobsoni Oudemans. Two indices to evaluate the efficacy of the treatments were adopted: percentage change in mite infestation of worker-sealed brood cells considering only treated hives and percentage change in mite mortality, and the natural variation in mite populations recorded in control hives during the trial. All acaricide treatments reduced the level of mite infestation of both sealed brood and adult bees. However, their effectiveness was slightly reduced in comparison to previous studies because of mite resistance phenomena. Portions of polyethylene strips of flumethrin from treated hives were sampled weekly to determine acaricide persistence using gas chromatography. After 4 wk, a slight reduction (approximately 9%) of the active ingredient content was observed. A laboratory bioassay also was performed to establish the resistance of adult female mites to fluvalinate. Mites were sampled from the experimental apiary and from various Sardinian apiaries which had primarily been subjected to fluvalinate applications in plastic strips or wood inserts for years. Mite resistance varied from 0 to 96%, depending on the acaricide management adopted. The lowest resistance level occurred in an apiary where pyrethroids had never been used, whereas the highest level occurred in an apiary, with intensive use of fluvalinate in wood inserts.

Distribution and composition of polycyclic aromatic hydrocarbons within experimental microcosms treated with liquid creosote

AbstractTemporal changes in the distribution and relative composition of 15 priority polycyclic aromatic hydrocarbons (PAHs) in water, sediment, and absorbed to polyvinylchloride (PVC) strips were assessed following direct application of liquid creosote to aquatic microcosms. Fourteen microcosms were treated with nominal creosote concentrations ranging from 0.06 to 109 mg/L and two microcosms served as controls. Quantitative analysis of PAHs was performed using high‐performance liquid chromatography equipped with a fluorescence detector. Post‐treatment concentration of PAHs in water decreased exponentially with time. At 2 d posttreatment, total PAHs (∑ PAH) ranged from 7.3 μg/L (lowest treatment) to 5,803.2 μg/L (highest treatment); by 84 d, ∑ PAH in the same microcosms was reduced to between 0.8 μg/L and 13.9 μg/L, respectively. The relative composition of PAHs in the water also changed with time; at 2 d posttreatment, ∑ PAH in the lowest treatment (7.3 μg/L) reflected contribution from nine PAHs, whereas only two PAHs contributed to this concentration (0.8 μg/L) at 84 d. Low and high molecular weight (mol. wt.) PAHs were lost first from the water column, followed by PAHs of intermediate mol wt. In sediments, a dose‐dependent increase in ∑ PAH was observed above 0.59 mg/L creosote up to 28 d, followed by a decline thereafter in all but the highest treatment. Total PAHs in sediment ranged from 0.91 μg/g (lowest treatment) to 63.9 μg/g (highest treatment) at 28 d. A dose‐dependent relationship was also observed in PVC strips, with ∑ PAH on PVC ranging from 0.05 to 88 μg/cm2 at 31 d and 0.04 to 18.4 μg/cm2 at 58 d posttreatment. A mass balance evaluation showed that 88.3% of PAHs was lost from the system after 1 month, indicating that liquid creosote is attenuated relatively quickly in aquatic environments.

Rapid diagnosis of schistosomiasis by antigen detection in urine with a reagent strip

For the rapid and simple diagnosis of schistosomiasis, a reagent strip assay for detection of circulating cathodic antigen (CCA) in urine was developed. The test was based on a previously developed sandwich enzyme-linked immunosorbent assay (ELISA) using a combination of two anti-CCA monoclonal antibodies. For the reagent strip assay, as the capture matrix, monoclonal antibody was coated onto a nitrocellulose membrane and mounted on polyvinyl chloride strips. Urine samples were then tested in an assay consisting of a combined incubation step of the urine sample and biotinylated detecting antibody followed by incubation in streptavidin peroxidase and a subsequent staining. The specificity and the sensitivity of the assay, as determined with urine samples of 61 uninfected controls and 67 Schistosoma mansoni-infected individuals, were 96.7 and 95.5%, respectively. The results of the reagent strip assay compared very well with microscopical parasitological diagnosis by the standard Kato-Katz method for the same individuals. The reagent strip test has a lower detection limit of 1 ng of CCA per ml and can be completed in 75 min. By the inclusion of two reference bands on the strips, standardized reading could be achieved. This reagent strip assay is a promising tool for qualitative diagnosis of S. mansoni infections in control programs.

An Improved PVC Strip Ml-Elisa Technique for Diagnosis of Recent Cases of Amoebiasis

Conventional plate ML-ELISA technique for diagnosis of recent cases of amoebiasis was converted into a simple polyvinyl chloride strip multilayer-enzyme linked immunosorbent assay (PVC strip ML-ELISA). This report details the development and preliminary characterization of the PVC strip ML-ELISA method for Entamoeba histolytica antigen detection in human fecal samples. In addition, we evaluated the relative efficacies of the PVC strip ML-ELISA and the conventional plate ML-ELISA methods by screening different categories of amoebiasis patients and other intestinal parasites. A significant correlation was found (P less than 0.01) between the two assay methods with reference to sensitivity and specificity of detecting E. histolytica antigens. However, with reference to operational case and economy, the PVC strip ML-ELISA may be performed even by paramedical technical personnel under field conditions.

Laboratory Method for Measuring the Attractiveness of Pheromones to Adult Musca domestica (Diptera: Muscidae)

A technique was developed for evaluating the effects of pheromones on adult house fly, Musca domestica (L.) feeding. U-shaped pipettes were placed next to Celotex blocks treated with (Z)-9-tricosene in cages with 200 adult house flies. The pipettes were filled with sucrose so that a positive meniscus formed where flies could feed. The amount of sucrose consumed was determined by measuring the amount needed to refill the pipettes after 24 h. Flies ingested significantly more sucrose solution placed near a Celotex block treated with (Z)-9-tricosene than from a control without pheromone. The cis and cis/trans isomers of (Z)-9-tricosene were equally effective in increasing ingestion. Commercially available polyvinylchloride strips were not as effective as the Celotex block when both were treated with (Z)-9-tricosene. Evaluation of these (Z)-9-tricosene presentations using our new laboratory method precluded the need for more costly field evaluations.

A comparison of immunological methods for the detection of Trichinella spiralis antigen

Eight immunological methods all using the same monoclonal antibody reagent were compared for the detection of Trichinella spiralis antigen. These were based on: (1) the direct adsorption of the antigen to the immunoadsorbent (nitrocellulose membrane, polyvinyl chloride strip or microplate); (2) capture of the antigen by antibodies pre-sensitized on the immunoadsorbent; and (3) latex agglutination. The methods found suitable were: (a) capture radioimmunoassay (capture-RIA) (sensitivity: < 0.5 μg/ml antigen); (b) direct enzyme immunoassay (direct-ELISA) (<0.5 μg/ml); (c) tube latex agglutination test (2.2 μg/ml); and (d) direct immunodot assay (8.8 μg/ml). However, the performance of the direct-ELISA was greatly affected by the presence of each of three extraneous substances (bovine serum albumin (BSA), lipopolysaccharide (LPS), normal swine muscle homogenate (NSM)) added to the antigen sample. The direct immunodot assay was also affected by the presence of BSA or LPS, whereas both capture-RIA and the tube latex agglutination methods were affected by the presence of NSM only. The findings are discussed with a view of detecting T. spiralis larvae directly from pork samples by immunological means.

Prophylactic efficiency and longevity of polyvinyl chloride strips containing permethrin for control of northern fowl mites (Acari: Macronyssidae) on caged chickens.

Cockerels in cages, each treated with two polyvinyl chloride (PVC) strips containing 9.7% permethrin, were resistant to infestation by northern fowl mites, Ornithonyssus sylviarum (Canestrini and Fanzago) for at least 64 days. The protection offered by such strips was greater than that afforded by a single treatment with 0.25% permethrin dust. Northern fowl mite populations on laying hens in commercial facilities were effectively controlled for more than 14 months by two, four, or six PVC-permethrin strips in each cage. Over the 439-day trial, ca. 12% of the total permethrin available was released from the experimental PVC strips. The mite control observed resulted from average total doses of permethrin ranging from 31.1 to 112.1 mg per hen.

The Effectiveness of Polyvinyl Chloride Plastic Bands Impregnated with Permethrin as a Control for the Northern Fowl Mite, Ornithonyssus sylviarum (Canestrini and Fanzago), Infesting Caged Laying Chickens

Caged White Leghorn hens were used to study the effectiveness of polyvinyl chloride (PVC) bands impregnated with 10% permethrin (50 mg/active ingredient/band) for control of the northern fowl mite (NFM), Ornithonyssus sylviarum (Canestrini and Fanzago). The PVC bands were attached two ways, either to the leg of the bird or to the cage floor. Leg band treatments included one, two, three, four, and six birds banded (one band per bird) per cage of six birds. Cage band treatments included one, two, and four PVC strips attached to the cage floor. The attachment of PVC bands to cages was very effective in controlling NFM. Birds in the treatment with four bands attached to the cage floor were essentially mite free for the duration of the 19-week test. Based on this test, the leg banding technique does not seem to be as effective or practical for controlling NFM on caged layers as is attachment of the bands to the cage floor. The use of permethrin-impregnated PVC bands or strips attached to the floor of poultry cages shows promise for effective NFM control and for relieving stress on birds resulting from conventional spraying or dusting treatments.

An in vitro evaluation of a new plasticizer for polyvinylchloride medical devices.

The rate of Hatcol-200 (H-200) leaching from polyvinylchloride (PVC) by serum is one-hundredth that of di-2-ethylhexyl phthalate (DEHP) as determined by radioassay. There is a proportional decrease in leachability of DEHP but not of H-200 as the plasma proteins are diluted. Saline extracts of DEHP demonstrated a low but progressive rate of leaching with an accumulation of 11 microgram/ml after seven weeks whereas H-200 showed only a constant residue of 0.35 microgram/ml. Normal human serum incubated for three weeks at 37 C with PVC strips plasticized with DEHP produced significant growth-inhibition of human diploid fibroblasts. Human serum incubated in an identical manner with PVC plasticized with H-200 for up to four weeks demonstrated no effect on tissue culture. These studies indicate that H-200 deserves further evaluation as a replacement for DEHP in PVC biomedical devices.

Pest Control and Phytotoxicity on Indoor Ornamental Plants with Dichlorvos Fumigation 1

Abstract A 20% dichlorvos impregnated polyvinyl chloride (PVC) resin strip (6.3 × 15.9 × 0.7 cm) per 28.3 m3 interior room significantly reduced the number of mealybugs (Phenacoccus solani Ferris) 48 hour posttreatment. Greenpeach aphid (Myzus persicae Sulzer) and twospotted spider mite (Tegranychus urticae Koch) populations were not suppressed. Exposure of pests to a stake label with an attached dichlorvos impregnated PVC strip produced the same effects as the room fumigation test. Placement of a 20% dichlorvos PVC resin strip per 25.4 × 70 cm polyethylene bag with infested plant material for 12 or 24 hr reduced populations of M. persicae, P. solani and T. urticae, however, 3 exposures at 7-day intervals were more effective in maintaining low populations. Fumigation in bags produced phytotoxic effects with specific plants.

An inhalational toxicity study with dichlorvos

Dogs, cats and rabbits were continuously exposed for eight weeks to dichlorvos atmospheres generated from impregnated polyvinyl chloride strips. Concentrations of dichlorvos in air were produced in the range 0.05 to 0.3 μg/l. No effects were found on the general health, behaviour, plasma and erythrocyte cholinesterase activities and electroencephalographic patterns of the animals.

Optical anisotropy in oriented polyvinyl chloride

This paper reports measurements of the variations of residual optical birefringence and extinction direction with residual strain occurring in tensile test pieces cut from oriented polyvinyl chloride strip and extended in simple tension. The strips were oriented by prior extension and both the degree of orientation and the angle between the orientation direction of the strips and the direction of subsequent extension of the test pieces were varied.The experimental results are discussed in terms of a molecular orientation model due to Kuhn and Grün and developed in this paper to apply to cases such as described here, in which the transverse contraction accompanying the longitudinal extension of the test pieces is anisotropic. Agreement between experiment and theory is reasonable in view of the simple assumptions made.