A novel XYZ electrospinning that orients the trajectory and collimates the electrified fluid jet of polymer nanofibers by induced electric fields.

Electrospinning is a process in which high voltage creates nanostructured fibers with random orientation from a polymer solution. A novel electrospinning instrument was designed and constructed, capable of orienting and collimating the trajectory of the electrified fluid jet. The equipment collimates and adjusts the electrified fluid jet in the X-Y directions using deflector plates connected to a variable electric field. Simultaneously, different membrane thicknesses can be selected, i.e., in the Z direction. Additionally, by programming the sinusoidal function generator to perform an X-Y sweep, Lissajous figures (LF) were obtained. SEM images obtained through XYZ electrospinning of PVC and PVDF membranes were used to determine the control achieved over the orientation distribution of the processed nanofibers and the modification of their diameter, with and without applying the electric field to the deflector plates. The nanofibers obtained from the polymeric membranes, which originated after the straight segment of the Taylor cone, did not exhibit a random trajectory and position. Instead, the collimated electrified fluid jet deposited them in a cross pattern (X-Y) on the collector-cathode plate.

Recycled polyvinyl chloride microplastics: investigation of environmentally relevant concentrations on toxicity in adult zebrafish.

Recycled polyvinyl chloride (PVC) microplastics have been detected in the aquatic environment. These recycled microparticles contain chemicals that are released into the environment reaching different organisms. Although the problem of the presence of recycled PVC microparticles in the environment is evident, the toxicological consequences of this contaminant to exposed organisms remains to be better determined. The aim of this study was to investigate the toxicity attributed to exposure to environmentally relevant concentrations of recycled PVC microplastics in adult zebrafish (Danio rerio). The experimental groups were: negative control, vehicle control, positive control, and recycled microplastics (20 ± 5 µm) at 5, 10 or 20 µg/L. Zebrafish (D. rerio) were exposed to respective treatments for 96 hr. Locomotion and oxidative status parameters were measured and mortality recorded. The positive control group presented increased mortality rates and decreased locomotor activity. Animals from the vehicle group did not show marked differences. Finally, no significant disturbances were found in survival rate, locomotion pattern and oxidative status of animals exposed to recycled PVC microparticles at 5, 10 or 20 µg/L. Taken together our results suggest that recycled PVC microplastics in this particle size range do not appear to exert harmful effects on exposed adult D. rerio. However, these results need to be carefully observed due to limitations including size of particle and duration of exposure parameters that might affect ecological consequences. It is suggested that additional studies applying other particles sizes and chronic exposure are needed to more comprehensively verify the toxicity of the contaminant investigated here.

Wheelchair Axle Position Effect on the Propulsion Performance of Persons With C7 Tetraplegia: A Repeated-Measures Study.

Objectives: To assess the changes in speed, stroke frequency, acceleration, and shoulder range of motion (ROM) associated with different wheelchair axle positions in people with chronic C7 tetraplegia. Methods: This repeated-measures study was conducted at the Chronic Spinal Cord Injury Unit, FLENI Escobar, Argentina. The speed, stroke frequency, acceleration, and shoulder ROM during wheelchair propulsion were measured in nine participants with C7 spinal cord injury (SCI) in four different axle positions (forward and up, forward and down, backward and down, backward and up). Two strokes performed at maximum speed were analyzed on a smooth level vinyl floor in a motion analysis laboratory. Data were analyzed for significant statistical differences using the Friedman test and the Wilcoxon signed rank test. Results: Our study showed significant differences in the speed with axle position 1 (1.57 m/s) versus 2 (1.55 m/s) and position 2 (1.55 m/s) versus 4 (1.52 m/s). The shoulder ROM showed a significant difference in the sagittal plane in position 2 (59.34 degrees) versus 3 (61.64 degrees), whereas the stroke frequency and the acceleration parameters showed no statistically significant differences with the different rear axle positions. Conclusions: Our study showed that modifying the rear axle position can improve the propulsion speed and produce changes in the shoulder ROM in the wheelchair propulsion of individuals with C7 SCI.

Freshwater-Derived Streptomyces: Prospective Polyvinyl Chloride (PVC) Biodegraders.

Polyvinyl chloride (PVC) is widely used in industrial applications, such as construction and clothing, owing to its chemical, physical, and environmental resistance. Owing to the previous characteristics, PVC is the third most consumed plastic worldwide and, consequently, an increasing waste accumulation-related problem. The current study evaluated an in-house collection of 61 Actinobacteria strains for PVC resin biodegradation. Weight loss percentage was measured after the completion of incubation. Thermo-gravimetric analysis was subsequently performed using the PVC incubated with the three strains exhibiting the highest weight loss. GC-MS and ionic exchange chromatography analyses were also performed using the culture media supernatant of these three strains. After incubation, 14 strains had a PVC weight loss percentage higher than 50% in ISP-2 broth. These 14 strains were identified as Streptomyces strains. Strains 208, 250, and 290 showed the highest weight loss percentages (57.6-61.5% range). The thermal stability of PVC after bacterial exposure using these three strains was evaluated, and a modification of the representative degradation stages of nonincubated PVC was observed. Additionally, GC-MS analysis revealed the presence of aromatic compounds in the inoculated culture media, and ionic exchange chromatography showed chloride release in the supernatant. A mathematical relation between culture conditions and PVC weight loss was also found for strains 208 and 290, showing an accuracy up to 97.99%. These results highlight the potential of the freshwater-derived Streptomyces strains as candidates for the PVC biodegradation strategy and constitute the first approach to a waste management control scale-up process.

Theoretical Study of Vinyl-Sulfonate Monomers and Their Effect as the Dopants of Polyaniline Dimers.

Establishing the structure-property relationships of monomers and polymers via theoretical chemistry is vital for designing new polymer structures with a specific application. Developing bifunctional monomers with selective polymerizable sites is one of the strategies employed to obtain complex polymeric systems. In this work, a theoretical study on anilinium 2-acrylamide-2-methyl-1-propanesulfonate (ani-AMPS) and anilinium 4-styrenesulfonate (ani-SS) monomers and their respective doped polyaniline dimer (PAni-d AMPS or PAni-d SS) was performed. The study focused on understanding the susceptibility of the vinyl group to a radical attack and the conformation changes resulting from the coordinated covalent bond between sulfonate and aniliniun. Applying Density Functional Theory with the B3LYP functional and a basis set of 6 - 31 + G(d,p), the structures of the ani-AMPS, ani-SS, PAni-d AMPS, and PAni-d SS were optimized, and the different chemical descriptors were determined. The simulation showed that the reactivity of the vinyl group in the ani-AMPS is slightly higher. The sulfonate group undergoes a conformational change when bonding with PAni-d AMPS or PAni-d SS compared to its respective bifunctional monomer. Additionally, the electronegativity of PAni-d depends on the dopant's structure. Thus, the bonded spacer between the vinyl and sulfonate groups (dopant) plays a notable role in the final characteristics of ani-AMPS, ani-SS, PAni-d AMPS, and PAni-d SS.

Protective Barriers and Radiant Exposure Delivered from Light-curing Units.

OBJECTIVE: To evaluate the influence of different protective barriers as a function of the photoactivation distances on the radiant exposure of several light-curing units (LCU). The influence of the protective barriers on the degree of conversion of an adhesive resin was also evaluated. METHODS: Five LCUs were evaluated: Valo Cordless-used in standard mode (Ultradent, South Jordan, USA); Radii-cal-used in continuous mode (SDI, Bayswater, AU); Emitter D-used in continuous mode (Schuster, Santa Maria, BR); Bluephase N-used in high-intensity mode (Ivoclar Vivadent, Schaan, LI); and Rainbow Curing Light-used in continuous mode (Axdent, Guangdong, CN). For each LCU, radiant exposure was measured with a spectrometer (MARC Resin Calibrator) using three different protective barriers (low-density polyethylene, polyvinyl chloride, or Radii-cal barrier sleeves) and five photoactivation distances (0, 2, 5, 10, and 20 mm). The degree of conversion of an adhesive resin (Adper Scotchbond Multi-Purpose, 3M ESPE, St. Paul, USA) was measured through Fourier-transform infrared spectroscopy. The translucency parameter of protective barriers was measured with a spectrophotometer. For all statistical tests, a significance level of α = 0.05 was set. RESULTS: For all LCUs tested, radiant exposure was found to be significantly influenced by both protective barriers and curing distance (p≤0.001). In general terms, all the protective barriers significantly decreased the radiant exposure. Radii-cal barrier sleeves were the protective barrier that most decreased the radiant exposure. Irrespective of the protective barrier used, none of the LCU equipment reached the required minimum radiant exposure of 16 J/cm2 at 10 mm of curing distance. The degree of conversion was not effected by either LCU or a protective barrier (p≥0.211). CONCLUSIONS: Protective barriers and photoactivation distance reduced the radiant exposure emitted by different LCUs.

Assessment of phytoremediation potential of native plant species naturally growing in a heavy metal-polluted industrial soils.

The present study was carried out in Hayat Abad Industrial Estate located in Peshawar to assess the levels of cadmium (Cd) that were present in the soil as well as the plant parts (Roots and shoots). To evaluate the phytoremediation potential of the plants different factors i.e. Bioconcentration Factor (BCF), Translocation Factor (TF), and Bioaccumulation Coefficient were determined. These plants were grown in their native habitats (BAC). We have analysed, cadmium concentration from soil which are collected from 50 different locations ranged from 11.54 mg/Kg (the lowest) to 89.80 mg/Kg (highest). The maximum concentration (89.80 mg/Kg) of cadmium was found in HIE-ST-16L Marble City and HIE-ST-7 Bryon Pharma (88.51 mg/Kg) while its minimum concentration (12.47 mg/Kg) were detected in the soil of Site (HIE-ST-14L Royal PVC Pipe) and (11.54 mg/Kg) at the site (HIE-ST-11 Aries Pharma). Most plant species showed huge potential for plant based approaches like phyto-extraction and phytoremediation. They also showed the potential for phyto-stabilization as well. Based on the concentration of cadmium the most efficient plants for phytoextraction were Cnicus benedictus, Parthenium hysterophorus, Verbesina encelioides, Conyza canadensis, Xanthium strumarium, Chenopodium album, Amaranthus viridis, Chenopodiastrum murale, Prosopis juliflora, Convolvulus arvensis, Stellaria media, Arenaria serpyllifolia, Cerastium dichotomum, Chrozophora tinctoria, Mirabilis jalapa, Medicago polymorpha, Lathyrus aphaca, Dalbergia sissoo, Melilotus indicus and Anagallis arvensis. The cadmium heavy metals in the examined soil were effectively removed by these plant species. Cerastium dichotomum, and Chenopodium murale were reported to be effective in phyto-stabilizing Cd based on concentrations of selected metals in roots and BCFs, TFs, and BACs values.

A global pollutant (PVC-polyvinyl chloride) applied as heavy metal binder from aqueous samples: green principles from synthesis to application.

We have developed a clean route for the modification of polyvinylchloride surface (PVC) with 4-amino-5-hydrazino-1,2,4-triazole-3-thiol molecule. The modification reaction was investigated through Fourier Transform Infrared Spectroscopy (FTIR) and X-ray Photoelectron Spectroscopy (XPS) analysis. According to our findings, S-H groups are responsible to the molecule attachment and nitrogen atoms are directly involved in metal ion coordination. These results are in agreement with the pseudo-second-order kinetic model, which infers that chemisorption is the main mechanism for metal removal. Adsorption isotherms of Cd(II), Cu(II) and Pb(II) follow the Langmuir model and the results indicated that Ns values are 0.39, 0.52 and 0.15 mmol g-1, respectively. The calculated Ømax values for Cu(II), Pb(II) and Cd(II) were 3.93, 2.95 and 1.13, respectively, indicating that three types of complex are formed depending on the adsorbed species. Therefore, it can be concluded that PVC use as adsorbent is feasible since it requires a simple modification reaction with nontoxic and low-cost solvents.

Postharvest conservation of Formosa 'Tainung 1' papaya under refrigeration, modified atmosphere, and chitosan

The objective of this work is to evaluate the use of modified atmosphere and chitosan as an alternative to chemical treatment in postharvest conservation of 'Tainung 1' papaya under refrigeration. The experiment comprised of completely randomized blocks with four replications, one fruit per replication, with a 2 × 4 × 4 factorial design as follows: two types of packaging (with or without polyvinyl chloride [PVC] stretchable film, thickness of 17 µm), four treatments (control, 2% chitosan, 4% chitosan, and prochloraz fungicide with 33.75 g a.i.·100 L­1), and four storage periods (0, 7, 14, and 21 days) at 10 °C and relative humidity (RH) of 90 ± 5%. The variables evaluated were mass loss (ML), external appearance, titratable acidity (TA), soluble solids (SS), vitamin C, reducing sugars (RS), and total sugars (TS). The storage of 'Formosa' papaya under refrigeration at 10 °C and RH of 90 ± 5% associated with PVC provided a low percentage of ML and longer conservation time of apparent quality (up to 7 days) in relation to fruits with no storage in PVC. The external appearance of fruits was preserved for up to 14 days by the PVC + 4% chitosan treatment and for up to 21 days by the PVC + prochloraz fungicide treatment. The treatment PVC + 4% chitosan associated with refrigeration is efficient in maintaining fruit quality. It is, for up to 14 days, a viable alternative to the use of prochloraz fungicide for postharvest conservation of 'Formosa' papaya.

Influence of biosafety materials of the laser output power.

Biosafety materials used in the correct handling of low power laser equipment may interfere on the power delivered at the target tissue and, possibly, on the effects on biological tissues. The aim of this study was to evaluate the interference of the use of polyvinyl chloride (PVC) and polyethylene (PEAD) protection materials on the output power of low power lasers. Two low power diode laser devices with different wavelengths (red and infrared) were used. For each wavelength, two protection materials and two evaluation times (before and after protection) were considered. The output power (mW) was measured with the tip positioned in close contact with the power meter receiver. Parametric statistical test, two-way ANOVA for repeated measures (protection material and time), was performed considering the level of significance of 5%. In respect to "time", all groups had the output power reduced after placing the protective material (p < 0.05). Comparing the protection materials, the PEAD showed a greater reduction in output power than the PVC for both red and infrared wavelengths. It was concluded that, among the biosafety materials tested, PVC is the most suitable for the protection of the tip of the low power lasers.

Effects of different banana crop residue hays on ensiling BRS capiaçu grass on fermentation profile, aerobic stability and nutritional value of silage / Efeitos de diferentes fenos de resíduo da bananicultura na ensilagem do capim-BRS capiaçu sobre o perfil de fermentativo, estabilidade aeróbia e valor nutricional da silagem

The objective of this study was to evaluate the BRS capiaçu grass silage combined with different hays of banana crop residue on fermentation profile, aerobic stability and nutritional value. The treatments consisted of elephant grass cv. BRS capiaçu (Pennisetum purpureum Schum.) ensiled with 37.44% banana peel hay, 36.06% banana pseudostem hay and 37.00% banana leaf hay, on a dry matter (DM) basis and control silage (no additive). The experimental design used was completely randomized, with five treatments and five replicates. Forage was collected when it reached 3.5 meters in height (90 days). Experimental PVC silos of known weight, 50 cm long, 10 cm diameter, were used for silage making. For all treatments, silage aerobic stability breakdown started after 64 hours exposure to air. The BRS capiaçu grass control silage or silage combined with pseudostem hay (mean of 73.15 kg t GM-1) presented effluent losses 40.46% higher than those observed for BRS capiaçu grass silage + banana leaf hay and 69.17% in relation the BRS capiaçu grass silage + banana peel hay. The inclusion of banana crop residue (hay) when ensiling BRS capiaçu grass decreased 13.93% gas losses compared to the control silage (mean of 3.11% DM). Higher values of total digestible nutrients, metabolizable energy and digestible energy content was found in BRS capiaçu grass silage + with banana peel hay. The greater in vitro dry matter digestibility and in vitro neutral detergent fiber digestibility was observed for BRS capiaçu grass silage combined with pseudostem hay. The inclusion of 37.44% banana peel hay improves the fermentation profile and aerobic stability of BRS capiaçu grass silage.(AU)

Ojetivou-se por meio desta pesquisa avaliar a silagem de capim-BRS capiaçu associada com diferentes fenos de resíduos da cultura da banana sobre o perfil fermentativo, estabilidade aeróbia e valor nutricional. Os tratamentos consistiram de capim-elefante cv. BRS capiaçu (Pennisetum purpureum Schum.) ensilado com 37,44% de feno de casca de banana, 36,06% de feno de pseudocaule de banana e 37,00% de feno de folha de bananeira, à base da matéria seca (MS), e a silagem controle (sem aditivo). O delineamento experimental utilizado foi inteiramente casualizado com cinco tratamentos e cinco repetições. A forragem foi coletada quando atingiu 3,5 metros de altura (90 dias). Para a produção da silagem, foram utilizados silos experimentais de PVC de peso conhecido, com 50 cm de comprimento e 10 cm de diâmetro. Para todos os tratamentos, a quebra da estabilidade aeróbia da silagem iniciou a partir de 64 horas de exposição ao ar. A silagem de BRS capiaçu controle ou associada ao feno de pseudocaule (média de 73,15 kg t MN-1) apresentaram perdas de efluentes 40,46% maiores do que as observadas para a silagem de BRS capiaçu associada ao feno de folha de bananeira e 69,17% em relação à silagem de BRS capiaçu associada à casca de banana. A inclusão dos resíduos da cultura da banana (feno) na ensilagem do capim- BRS capiaçu diminuiu 13,93% as perdas por gases em comparação com a silagem controle (média de 3,11% da matéria seca - MS). Maiores teores de nutrientes totais digestíveis, energia metabolizável e energia digestível foram verificadas na silagem de BRS capiaçu associada à casca de banana. A maior digestibilidade in vitro da matéria seca e da fibra em detergente neutro foi verificada na silagem de BRS capiaçu associada com feno de pseudocaule. A inclusão de 37,44% de feno de casca de banana melhora o perfil fermentativo e a estabilidade aeróbia da silagem de capim- BRS capiaçu.(AU)

Reusable Enzymatic Strip for Detection of Arsenic

HIGHLIGHTS Arsenic is considered as one of the highly hazardous elements in the environment and a serious carcinogen for the human health. An enzymatic method has been described by using arsenite oxidase for arsenic detection. Residual activity of the immobilized enzyme was 43% of the initial activity after being recycled 10 times.

Abstract Arsenic is considered as one of the highly hazardous elements in the environment and a serious carcinogen for the human health. More attention has taken towards the arsenic due to its presence in ground water in India, China, Bangladesh, Inner Mongolia and several other regions of the world. It's been a challenge to remove arsenic due to the lack of its efficient detection approach in the complicated environmental matrix. The proposed method describes an enzymatic method for arsenic determination using arsenite oxidase, which catalyzes the oxidation of arsenite to arsenate. Hence, a colorimetric PVC strip with immobilized arsenite oxidase has been developed to detect the arsenic concentration and also having potential for the field-testing. The influence of the optimal conditions i.e. pH, temperature, storage stability, and reusability of free and immobilized enzyme were evaluated and compared. The results have shown that the stabilities were significantly enhanced compared with free counterpart. Residual activity of the immobilized enzyme was 43% of the initial activity after being recycled 10 times. We approve that this novel low cost immobilized carrier presents a new approach in large scale applications and expected to act as a model for establishment of indigenous arsenic sensor in miniature form.

Radioprotective efficacy of plastic polymer against the toxicogenomic effects of radiopharmaceutical 18F-FDG on human lymphocytes.

BACKGROUND: Healthcare workers occupationally exposed to 18F-FDG cannot wear protective equipment, such as lead aprons, since the interaction between high energy radiation (511 keV) and metal increases the dose of radiation absorption. The objective of this study was to evaluate the shielding efficacy of a plastic polymer against the toxicogenomic effects of ionizing radiation in human lymphocytes, using cytokinesis-block micronucleus assays. METHODS: Human peripheral blood lymphocytes were isolated from three subjects and cultured under standard conditions. The cultures were exposed to 300 mCi of 18F-FDG at a distance of 10 cm for 10 min, in the absence of shielding or with lead, polymer, and lead + polymer shields. RESULTS: Lead shielding was found to increase the number of counts detected by Geiger-Müller radiation monitors as a consequence of the photoelectron effect. Conversely, the lead + polymer shield reduced the number of counts. The lead, polymer, and lead + polymer shields significantly reduced the frequency of micronuclei, nucleoplasmic bridges, and nuclear buds induced by ionizing radiation. Regarding cytotoxicity, only the lead + polymer shield re-established the cell cycle at the level observed for the negative control. CONCLUSIONS: Lead aprons that are internally coated with polymer increased the radiological protection of individuals occupationally exposed to 18F-FDG PET/CT, especially during examinations.

Randomized Clinical Trial Using Sterile Single Use and Reused Polyvinylchloride Catheters for Intermittent Catheterization with a Clean Technique in Spina Bifida Cases: Short-Term Urinary Tract Infection Outcomes.

PURPOSE: Urinary tract infections are common and severe complications in patients with spina bifida. Management includes intermittent bladder catheterization with single use or reused sterile catheters. There is insufficient evidence to set a standard among the different techniques. We determined whether single use polyvinylchloride catheters would reduce urinary tract infections compared to reused polyvinylchloride catheters in patients with neurogenic bladder due to spina bifida. MATERIALS AND METHODS: We performed a 2-arm randomized parallel clinical trial from 2015 to 2016 with an 8-week followup at our center in patients with neurogenic bladder caused by spina bifida. Patients were divided into single use and reused polyvinylchloride catheter groups. Evaluations were done on days 0, 7, 14, 28, 42 and 56. Participants reported symptoms and urine cultures were obtained. The primary outcome was urinary tract infection frequency, defined as positive urine culture plus fever, flank pain, malaise, or cloudy or odorous urine. Study eligibility criteria were age 2 years or greater, spina bifida diagnosis with regular clean intermittent bladder catheterization and no urinary tract infection at initial evaluation. RESULTS: The calculated sample size was 75. Of the patients 135 were screened, 83 were randomized and 75 completed followup. Mean age was 12.7 years (range 2-56) and there were 29 males and 46 females. No statistical difference was found between the single use vs reused catheter groups in the frequency of asymptomatic bacteriuria (32.4% vs 23.7%, p = 0.398) or urinary tract infections (35.2% vs 36.8%, p = 0.877). CONCLUSIONS: Single use polyvinylchloride catheters for intermittent bladder catheterization did not decrease the incidence of urinary tract infections in our patients with neurogenic bladder compared to reused polyvinylchloride catheters. These results are consistent with the 2014 Cochrane Review.

Extraction/Leaching of Metal-Containing Additives from Polyvinyl Chloride, Ethyl Vinyl Acetate, and Polypropylene Bags and Infusion Sets into Infusion Solutions.

Flexible medical devices are primarily made of plasticized polyvinyl chloride (PVC). In recent times, to avoid undesired migration of the PVC plasticizers, ethyl vinyl acetate (EVA) and polypropylene (PP) has replaced PVC. Nevertheless, other additives are necessary to generate useful polymeric materials. Metallic species present in such additives can also leach out into the infusion solutions. The migration of barium (Ba), cadmium (Cd), lead (Pb), tin (Sn), and zinc (Zn) from devices made from PVC, EVA, and PP was evaluated. Bags and infusion sets were decomposed and their metallic contents analyzed. Glucose, NaCl, and Tween 80 were assessed as extraction media. These solutions were stored in PVC, EVA, and PP bags, heat-sterilized, and stored for 8 months at room temperature. Aliquots were taken before and after sterilization and then once per month to determine the contents of the metals. Commercial glucose and NaCl infusions were analyzed by taking aliquots of the solutions from the bags and from the administration set after their administration to patients. The three polymers contained the five metals. Ba was found in the highest concentration in all samples, with a mean of 8.0 mg/kg in PVC, 4.2 mg/kg in EVA, and 4.7 mg/kg in PP samples. Despite this, the only element that migrated into the glucose, NaCl, and Tween 80 solutions was Zn. The same result was found for the commercial glucose and NaCl infusions. Moreover, the Zn concentration in the administration sets was on average 52% higher than that found in the bags.LAY ABSTRACT: Flexible medical devices for infusions and artificial nutrition are made of plastics, such as polyvinyl chloride (PVC), ethyl vinyl acetate (EVA), and polypropylene (PP). These polymers contain additives necessary to generate useful materials. Metallic species present in these additives can leach out into the infusion solutions and come into contact with patients. To assess the risk of patient exposure to these metals, we evaluated the migration behavior of barium (Ba), cadmium (Cd), lead (Pb), tin (Sn), and zinc (Zn) from devices made from PVC, EVA, and PP. Bags and infusion sets were analyzed. Glucose, NaCl, and Tween 80 were investigated as extraction media. The three polymers contained the five metals. Ba was found in the highest concentration in all samples. Despite this, the only element that migrated into the glucose, NaCl, and Tween 80 solutions was Zn.

Biodegradation of PCL and PVC: Chaetomium globosum (ATCC 16021) activity.

The increasing use of plastics in human activities has resulted in an enormous amount of residues which became a matter of great environmental concern. Scientific studies on the microbial degradation of natural and synthetic molecules show the potential of fungal application on cleaning technologies. The biodegradation of PCL (polycaprolactone) and PVC (polyvinyl chloride) films by Aspergillus brasiliensis (ATCC 9642), Penicillium funiculosum (ATCC 11797), Chaetomium globosum (ATCC 16021), Trichoderma virens (ATCC 9645), and Paecilomyces variotii (ATCC 16023) was studied. According to ISO 846-1978-"Testing of Plastics - Influence of fungi and bacteria", samples of the studied polymers were inoculated with a mix suspension of 106 fungal inoculum and maintained in moisture glass chambers in a bacteriological incubator at 28 °C for 28 days. The samples were analyzed by means of morphological and color changes, mass loss, optical microscopy (OM), and scanning electron microscopy (SEM) after 28 days of culturing. After the incubation period, visual observations of the PCL films showed many micropores and cracks, pigmentation, surface erosion and hyphal adhesion on the sample surfaces, and a mass loss of up to 75%. On the contrary, there was no evidence of PVC biodegradation, such as changes in color and significant mass loss. Chaetomium globosum ATCC 16021 was a pioneer in the colonization and attack of PCL, resulting in significant mass losses. Although PVC was less attacked by the ascomycete, the polymer supported the adhesion and growth of its fertile structures (perithecia), suggesting the fungal potential to degrade both plastics.

Building Ultrasound Phantoms With Modified Polyvinyl Chloride: A Comparison of Needle Insertion Forces and Sonographic Appearance With Commercial and Traditional Simulation Materials.

INTRODUCTION: Training using ultrasound phantoms allows for safe introduction to clinical skills and is associated with improved in-hospital performance. Many materials have been used to simulate human tissue in phantoms including commercial manikins, agar, gelatin, and Ballistics Gel; however, phantom tissues could be improved to provide higher-fidelity ultrasound images or tactile sensation. This article describes a novel phantom tissue mixture of a modified polyvinyl chloride (PVC) polymer, mineral oil, and chalk powder and evaluates needle cutting and ultrasonic properties of the modified PVC polymer mixture compared with a variety of phantom tissues. METHODS: The first experiment measured axial needle forces of a needle insertion into nine phantom materials, including three formulations of modified PVC. The second experiment used a pairwise comparison survey of ultrasound images to determine the perceived realism of phantom ultrasound images. RESULTS: It was found that the materials of Ballistics Gel and one of the PVC mixtures provide stiff force feedback similar to cadaver tissue. Other phantom materials including agar and gelatin provide very weak unrealistic force feedback. The survey results showed the PVC mixtures being viewed as the most realistic by the survey participants, whereas agar and Ballistics Gel were seen as the least realistic. CONCLUSIONS: The realism in cutting force and ultrasound visualization was determined for a variety of phantom materials. Novel modified PVC polymer has great potential for use in ultrasound phantoms because of its realistic ultrasound imaging and modifiable stiffness. This customizability allows for easy creation of multilayer tissue phantoms.

Continuous Exposure to Microplastics Does Not Cause Physiological Effects in the Cultivated Mussel Perna perna.

The environmental impact of microplastics is a challenging theme, especially under realistic experimental conditions. We investigated physiological responses to 0.1-1.0 µm PVC particles intake by the mussel Perna perna after a relative long-term exposure (90 days) at a less extreme concentration compared with previous studies (0.125 g/L). Microplastic intake was inferred by the presence of PVC in the feces of mussels, and physiological damages were assessed through ingestion rate, assimilation efficiency, growth rate, cellular and molecular biomarkers (lysosomal integrity, lipid peroxidation, and DNA damage), and condition index. All physiological responses showed nonsignificant effects of the microplastics on the exposed mussels. We suggest that, despite the experimental concentration of microplastics, mussels were able to acclimate to the exposure through their abilities for long-term recovery and tolerance to stresses. These data have positive implications for environmental health and in terms of human food resource because mussel farming is a worldwide practice that heavily relies on plastic materials, increasing the chances of microplastic exposure and mussels contamination.

Photosensitive multifunctional poly(vinyl alcohol) micelles for enhanced antitumor effect.

Polyvinyl alcohol (PVA) micelles were firstly synthesized by using hemin molecules as novel crosslinked bridges (PVA-H crosslinked micelles). On one hand, the crosslinked micelles can allow high stability against extensive dilution (1800-fold) to reduce side-effects; On the other hand, the bridges not only can destruct by means of laser irradiation (405nm, 200mw), but also can induce the production of singlet oxygen (1O2) and the release of 5-fluorouracil (5FU) (i.e. 46% release in 360min). But above all, that 5FU-loaded PVA-H crosslinked micelles irradiating by laser is more efficient than PVA-H crosslinked micelles and free 5FU in killing tumor cells, suggest the effective synergistic antitumor effect about chemotherapy and photodynamic therapy (PDT).

Identification of proteins involved in the adhesionof Candida species to different medical devices.

Adhesion is the first step for Candida species to form biofilms on medical devices implanted in the human host. Both the physicochemical nature of the biomaterial and cell wall proteins (CWP) of the pathogen play a determinant role in the process. While it is true that some CWP have been identified in vitro, little is known about the CWP of pathogenic species of Candida involved in adhesion. On this background, we considered it important to investigate the potential role of CWP of C. albicans, C. glabrata, C. krusei and C. parapsilosis in adhesion to different medical devices. Our results indicate that the four species strongly adher to polyvinyl chloride (PVC) devices, followed by polyurethane and finally by silicone. It was interesting to identify fructose-bisphosphate aldolase (Fba1) and enolase 1 (Eno1) as the CWP involved in adhesion of C. albicans, C. glabrata and C. krusei to PVC devices whereas phosphoglycerate kinase (Pgk) and Eno1 allow C. parapsilosis to adher to silicone-made implants. Results presented here suggest that these CWP participate in the initial event of adhesion and are probably followed by other proteins that covalently bind to the biomaterial thus providing conditions for biofilm formation and eventually the onset of infection.