Crystal Violet Solution Research Articles

Encapsulation of Stimuli-Responsive Fusion Proteins in Silica: Thermally Responsive Metal Ion-Sensitive Hybrid Membranes

ABSTRACTIn this study, we demonstrate the fabrication of hybrid membranes that exhibit discrete and reversible changes in permeability in response to changes in calcium ion (Ca2+) concentration and temperature. Fusion proteins comprising calmodulin (CAM) and elastin-like polypeptides (ELPs) were used as stimuli-responsive elements due to their ability to undergo a reversible lower critical solution temperature (LCST) phase transition, which is sensitive to Ca2+binding. The calmodulin elastin-like polypeptides fusions (CAM-ELPs) were incorporated into polymerizing silica networks using a simple sol-gel process and spin coating. Permeation experiments with solutions of crystal violet showed that the membranes are both Ca2+-responsive and thermally responsive. Under suitable pressure drop across the membranes, in the absence of Ca2+or below the LCST of the ELPs, the hybrid membranes are impermeable to water. After addition of Ca2+or above the LCSTs, they become permeable to water. The permeability can be toggled back and forth by sequential addition of calcium and ethylenediamine tetraacetic acid (EDTA). These results demonstrate that CAMELP/silica hybrid membranes can serve as tunable molecular filters whose permeability can be switched on and off in response to Ca2+and temperature.

Efficacy of alpha-cypermethrin treated mesh against African horse sickness virus vectors

worldwide. Episodes of EHV-3 reactivation and reexcretion in latently infected horses also serve as a source of virus. Although ECE has no direct effect on fertility or pregnancy, its economic impact on the equine industry resides in the need of temporarily withdrawing the stallions and mares from the reproductive activity. Prevention is based on segregating affected mares from reproduction. However, regarding that there are latently infected animals, in which the virus is reactivated and generally re-excreted subclinically, and that this phenomenon is not predictable, the prevention approach previously described does not eliminate the risk of contagion. Although it has not been fully explored, field observations and scarce experimental data are promising about the use of acyclovir and ganciclovir as topical medication on ECE lesion. The aim of this study was to compare the activity of selected antivirals compounds to inhibit or reduce the replication of EHV-3 in vitro. Monolayers of EDerm cells were infected with 500 ml of the virus, containing up to 30 pfu/well, as it was previously determined by a plaque titration method. Overlay medium with carboxymethyl cellulose 0.75%, supplemented with the different concentrations of each antiviral compound (acyclovir, ganciclovir and cidofovir), were added. Cells infected with the virus without antiviral treatment were used as a control. After incubation, cells were fixed and stained with 0.1% formalin-buffered crystal violet solution. The parameters to assess the efficacy of the antiviral compounds were plaque number and plaque size, expressed as percentage of inhibition. The concentration of each compound required to inhibit plaque number and plaque size by 50% (IC50%), was obtained from the dose-response (percentage of inhibition) curves generated from the data. The three compounds tested were able to reduce plaque number and plaque size induced by EHV-3 infection in EDerm cells. Ganciclovir proved most potent to reduce the number (IC50%: 0.04-1 mg/ml) and the size (IC50%: 0-0.1 mg/ml) of plaques of EHV-3 in vitro. Cidofovir was intermediately potent to reduce plaque number and plaque size with an IC50% of 1-10 mg/ml and IC50% of 0.4-4 mg/ ml respectively. Lastly, acyclovir was the least effective compound to reduce plaque number (IC50%: 8-20 mg/ml) and plaque size (IC50%: 4-10 mg/ml). As preliminary conclusions, ganciclovir displays the best overall inhibitory activity on EHV-3 in vitro. Further in vitro researchs are ongoing and in vivo experiments are also scheduled.

Non-intrusive method for thermal properties measurement of nanofluids

Nanofluid is considered a suitable way for enhancing the heat transfer performance of conventional fluids. In this article photoacoustic technique as a nonintrusive optical method has been used to measure thermophysical properties (diffusivity, effusivity and conductivity) of transparent nanofluids. TiO2 (≈20nm) and Al2O3 (3–7nm) nanoparticles have been prepared and utilized to prepare nanofluids at low volume concentration (0.1–1vol.%). The prepared nanoparticles were characterized by using X-ray diffraction and TEM. The base fluid was dilute solution of dye crystal violet as a light absorber of known extinction coefficient in deionized water. The measured thermal parameters of the base fluid do not significantly differ from that of deionized water. The results show that thermal parameters of both nanofluids increase as the particle concentrations increase and are higher than the values of the base liquid for all concentrations of TiO2 nanoparticles. Also despite thermal conductivity of bulk Al2O3 is larger than that of TiO2, thermal parameters of Al2O3 nanofluids are generally less than those of TiO2 nanofluids. This contradictory can be explained on the bases of particle size effect. Furthermore, using Hashin and Shtrikman lower bound we were able to estimate an order of magnitude reduction of thermal conductivity of Al2O3 nanoparticles relative to its bulk value.

Properties of PbO<sub>2</sub> Electrode Modified by AEO-7 for Electrocatalytic Degradation of Crystal Violet

In order to improve the performance of PbO2electrode, A kind of surface active agent – AEO-7 was added into nitric acid bath and modified PbO2electrode was prepared on stainless steel substrate by anodic oxidation. The modified variations on surface morphology of the electrodes were examined by Scanning Electron Microscopy(SEM); The polarization curves, Tafel curves and Cyclic voltammograms of modified and unmodified PbO2electrodes were compared in Crystal violet solution; The electrocatalytic activities were inspected by electrocatalytic degradation of crystal violet. It was found that the modified electrode showed higher oxygen evolution potential, better corrosion resistance, and more excellent electrocatalytic activity than the unmodified electrode.

Ni supported on Mg–Al oxides for continuous catalytic wet air oxidation of Crystal Violet

The continuous catalytic oxidation of aqueous Crystal Violet (CV) solutions has been investigated using a nickel catalysts (7wt%) supported over Mg–Al mixed oxides in a trickle-bed reactor. The influence of the temperature, pressure, gas flow and dye initial concentration were studied in the catalytic wet air oxidation of CV. The catalyst showed a very stable activity up to 350h on stream with an average total organic carbon (TOC) conversion of 64%. CV and TOC removal were very sensitive to the temperature. Dye conversion augmented from 44.7% at 120°C to 86.1% at 180°C. Dye conversion varied from 62.6 to 18.4%, TOC from 59.5 to 18.7% and TN from 66.6 to 14.0% within 10 to 50ppm of initial dye concentration. The leaching of Ni was 6wt% of the initial metal present in the catalyst and a 0.59% of carbonaceous deposit was formed onto the catalyst surface.

Calpain 2 Regulates Akt-FoxO-p27Kip1 Protein Signaling Pathway in Mammary Carcinoma

Calpain 2 Regulates Akt-FoxO-p27Kip1 Protein Signaling Pathway in Mammary Carcinoma

Optical Fiber-Based Surface-Enhanced Raman Scattering Sensor Using Au Nanovoid Arrays

Plasmonic properties of gold nanovoid array substrates for fiber-based surface-enhanced Raman scattering (SERS) sensing are studied numerically and experimentally. In the nanovoid arrays, each void has openings on both sides, bottom hole facing the fiber tip for introducing incident light and collecting scattered light and the top hole exposed to the analyte solution for interrogating analyte molecules in the voids. Electromagnetic field modes are confined strongly in and around these nanovoids, acting as localized plasmon resonators. The enhanced electric field extends hundreds of nanometers into the voids, resulting in a large SERS-active zone several orders of magnitude larger than nanoparticle-based structures. The effect of structural parameters of the nanovoid arrays, including void diameter, Au film thickness, and bottom hole diameter, on electric field confinement in the voids is investigated using three-dimensional finite difference time domain simulation. Au nanovoid arrays are fabricated using a scalable, inexpensive nanosphere lithography fabrication method. The largest SERS signal is realized by tuning the localized plasmon resonance peak of Au nanovoid arrays to the laser excitation wavelength. Multiplexed detection capability with the fiber-based SERS sensor using Au nanovoid arrays is demonstrated by measuring the Raman spectrum of a mixture solution of diethylthiatricarbocyanine and crystal violet.

Nanoparticles assembled by aptamers and crystal violet for arsenic(iii) detection in aqueous solution based on a resonance Rayleigh scattering spectral assay

Aptamer-assembled nanomaterials have captured much attention from the field of analytical chemistry in recent years. Although they have been regarded as a promising tool for heavy metal monitoring, report involving aptamer-based biosensors for arsenic detection are rare. Herein we developed a highly sensitive and selective aptamer biosensor for As(iii) detection based on a Resonance Rayleigh Scattering (RRS) spectral assay. Prior to As(iii) detection, we firstly assembled a variety of nanoparticles with different sizes via controlling the concentration of arsenic-binding aptamers in crystal violet (CV) solutions. The results of photon correlation spectroscopy (PCS) and scanning probe microscope (SPM) testified that the introduction of As(iii) had indeed changed the size of nanoparticles, which caused a great variation in the RRS intensity at 310 nm. In the presence of 100 ppb As(iii), a maximum decline in the ratio of RRS intensity was achieved for large nanoparticles assembled from 200 nM of aptamers and CV molecules, where the average size of nanoparticles had decreased from 273 nm to 168 nm. In the case of small nanoparticles, the maximum increase ratio of the RRS intensity was obtained when the concentration of aptamer was over 600 nM. Combined with an RRS spectral assay, an effective biosensor has been developed for As(iii) detection, using the above large and small nanoparticles as the target recognition element. The present biosensor has a detection limit as low as 0.2 ppb, a dynamic range from 0.1 ppb to 200 ppb, and high selectivity over other metal ions. Such an efficient biosensor will play an important role in environmental detection.

A Case of Pyriform Sinus Fistula Demonstrated on Computed Tomography after Gastrografin® Deglutition

The pyriform sinus fistula is a rare anomaly that derives from the third, fourth or fifth pharyngeal pouch, and may cause recurrent anterior neck abscesses and/or suppurative thyroiditis. A 16-year-old male presented with acute left anterior cervical swelling. Endoscopic examination showed pus pooling in the left pyriform sinus, and computed tomography (CT) revealed an irregular-shaped abscess in the left anterior cervical region. From these findings, a pyriform sinus fistula was suspected. The patient was treated with antibiotics, and the acute inflammation subsided temporarily. Videofluoroscopy and CT after gastrografin® deglutition were then performed. The latter clearly depicted the fistula arising from the left pyriform sinus extending down to the left thyroid lobe. The patient underwent transcervical resection of the fistula including a partial thyroidectomy. Immediately prior to resection, the fistula was stained by injecting crystal violet solution through the opening in the pyriform sinus using a curved laryngoscope. The fistula was readily identified intraoperatively by the injected stain, and successfully resected. The patient showed temporary vocal cord paralysis of the affected side, which recovered within 2 months after surgery. No recurrence has been seen in 8 months of follow-up. We would like to stress that CT combined with contrast medium deglutition is a powerful means to enable a definitive diagnosis of this anomaly and could thus be useful in planning a surgical procedure.

Application of Ni supported over mixed Mg–Al oxides to crystal violet wet air oxidation: The role of the reaction conditions and the catalyst

This study explores the ability of nickel catalysts supported over Mg–Al mixed oxides (Ni/HT) by incipient wetness impregnation technique for the catalytic wet air oxidation of aqueous crystal violet solutions. The effect of operational conditions such as temperature, pressure, pH, presence of the catalyst and initial dye concentration has been tested. It has been demonstrated that Ni/HT is an efficient catalyst for the CWAO of crystal violet (CV) at mild reaction conditions. The reaction which was carried out at its natural pH, showed to be the most efficient when Ni/HT was employed. The catalyst does not lose any of its activity in the recycling experiments performed, when CV degradation is considered.

Control of milk pH reduces biofilm formation of Bacillus licheniformis and Lactobacillus paracasei on stainless steel

Microbial biofilms present in dairy farms may contaminate milk during milk harvest and transfer diseases from the environment to cows. In order to reduce biofilm formation with respect to the role of pH, a study involving the control of milk pH during long-term biofilm formation of Bacillus licheniformis NBRC 12195 and Lactobacillus paracasei subsp. paracasei NBRC 15889 on stainless steel coupons in different dilutions of skim milk (0.1%, 1.0% and 5.0%) was conducted. During long incubation at 30 °C, pH decreased due to bacterial development in unadjusted samples. In pH-adjusted samples, pH was kept at around 7.0 by the addition of sterile sodium hydroxide. Biofilms formed on stainless steel coupons were daily stained by 0.1% Crystal Violet solution and assessed by the evaluation of optical density. The bacterial count of the suspensions showed that the control of pH enhanced the growth of bacteria in free-floating form. In contrast, optical densities of biofilms formed in the pH-adjusted samples were significantly lower than in the pH-unadjusted samples in all of three skim milk dilutions. Comparison of maximum OD values of adhered cells at different nutrient levels also implicated that for both tested strains, thicker biofilms were formed in milk dilutions at higher nutrient levels. These results suggested that, control of milk pH and milk residue level could significantly reduce biofilm formation of the tested bacteria.

Facile preparation of poly(acrylic acid–acrylamide) hydrogels by frontal polymerization and their use in removal of cationic dyes from aqueous solution

Frontal polymerization (FP) was used as a new facile technique for the preparation of poly(acrylic acid–acrylamide) (PAA) hydrogels obtained from acrylic acid (AAc) and acrylamide (AM) in the presence of N, N′-methylenebisacrylamide (MBA) as a crosslinker. The dependence of the front velocity and front temperature on the factors such as the ratio of AAc and AM, the content of MBA and initiator was investigated. The microstructure, dynamic swelling, morphology and cationic dyes removal of PAA hydrogels prepared via FP were studied by FTIR spectrum, FE-SEM and swelling measurements. The results showed that PAA hydrogels prepared via FP exhibited good swelling and adsorption capacity toward cationic dyes and the adsorption capacity of may reach 4.12 and 11.23 mg/g in crystal violet (CV) and basic magenta (BM) solution after 72 h, respectively.

Flavivirus NS4A-induced Autophagy Protects Cells against Death and Enhances Virus Replication

Flaviviruses include the most prevalent and medically challenging viruses. Persistent infection with flaviviruses of epithelial cells and hepatocytes that do not undergo cell death is common. Here, we report that, in epithelial cells, up-regulation of autophagy following flavivirus infection markedly enhances virus replication and that one flavivirus gene, NS4A, uniquely determines the up-regulation of autophagy. Dengue-2 and Modoc (a murine flavivirus) kill primary murine macrophages but protect epithelial cells and fibroblasts against death provoked by several insults. The flavivirus-induced protection derives from the up-regulation of autophagy, as up-regulation of autophagy by starvation or inactivation of mammalian target of rapamycin also protects the cells against insult, whereas inhibition of autophagy via inactivation of PI3K nullifies the protection conferred by flavivirus. Inhibition of autophagy also limits replication of both Dengue-2 and Modoc virus in epithelial cells. Expression of flavivirus NS4A is sufficient to induce PI3K-dependent autophagy and to protect cells against death; expression of other viral genes, including NS2A and NS4B, fails to protect cells against several stressors. Flavivirus NS4A protein induces autophagy in epithelial cells and thus protects them from death during infection. As autophagy is vital to flavivirus replication in these cells, NS4A is therefore also identified as a critical determinant of flavivirus replication.

Decolorization of dye solutions with Ruditapes philippinarum conglutination mud and the isolated bacteria

Application of Ruditapes Philippinarum conglutination mud (RPM) for decolorizing synthetic dye solutions was studied. RPM showed good activity for decolorization of Methylene Blue, Crystal Violet, Malachite Green, and Ink Blue. The amount of the RPM had great effect on the decoloration rate of the dye solutions. However, the decoloration rate did not continue to increase when the amount of mud exceeded the optimum dose. The temperature of the dye solution had a remarkable effect on the decolorization rate of Ink Blue solution, but had little effect on the other three dye solutions. The initial pH of the dye solutions evidently affected the decolorization rate of Malachite Green solution, but had less effect on the other three. The decolorization rate of the dye solutions increased significantly with treatment time within 8 hr, but tended to be steady after 8 hr for Methylene Blue, Crystal Violet and Malachite Green solutions, and after 12 hr for Ink Blue solution. The decolorization efficiencies for the four dye solutions under the optimum conditions were all above 90%. Seventeen strains screened from RPM showed flocculation ability for kaolin clay suspension. Out of them, the flocculation rate of strain ZHT3-9 and strain ZHT4-13 were up to 88.14% and 86.01%, respectively. ZHT3-9 was studied, and its decolorization rate for Methylene Blue, Crystal Violet, and Malachite Green reached 90.02%, 89.21%, and 80.29%, respectively. By morphological, physiological and biochemical characteristics analysis and 16S rRNA sequencing, the strain ZHT3-9 was identified as Arthrobacter sp.

Dosimetric characteristics of aqueous solution of crystal violet for applications in food irradiation

Aqueous solution of crystal violet has been evaluated spectrophotometrically as a gamma-ray chemical dosimeter. The response of the chemical dosimetric system has also been investigated under different environmental conditions, such as light and temperature. In the present study the response has been measured at two wavelengths; 588 nm (λmax of the irradiated solution) and 500 nm. The response of the crystal violet dosimeter was linear in the dose range of 50–550 Gy at pH 5.6 when absorption measurements were made at 588 and 500 nm. The response of the crystal violet dosimeter during post-irradiation storage at room temperature in dark showed slight decrease in absorbance at 588 and 510 nm but the response was almost stable at 460 nm. For higher doses, the change in the response was greater as compared to the low doses. Post-irradiation stability during diffused sunlight showed significant decrease in the response for higher dose at 588 and 510 nm and slower decrease in the response for lower dose at the above mentioned wavelengths. However the response was almost stable up to 97 days at 460 nm for higher and lower doses. At 4 °C, the decrease in the absorbance was slower at 588 and 510 nm while the response was almost constant at 460 nm. At higher temperatures, such as 40 °C, the decrease in the absorbance was greater at 588 and 510 nm while at 460 nm the absorbance was almost constant for about 3 months.

Water-in-oil emulsion separation within a milli-fluidic device

A milli-fluidic method capable of continuous passive separation of water-in-oil emulsions with an efficiency of ∼90% is described. Experiments used high oleic sunflower oil or mineral oil as the continuous phase and aqueous solutions of methylene blue, crystal violet, or dextran with methylene blue as the dispersed phase. To achieve continuous passive separation, a device with opposing channel walls of disparate hydrophobicity is used to stabilize cocurrent laminar flow of oil and water. The disparity in hydrophobicity of the channel walls is accomplished by defining one length of the channel with a hydrogel, in this case polyethylene glycol. Emulsion separation is facilitated by introducing the emulsion at the water/hydrogel interface. Advantages of performing separations at the milli-fluidic scale are presented.

SURFACE ADHESION OF SALMONELLA ENTERICA AND STAPHYLOCOCCUS AUREUS UNDER FLUCTUATING TEMPERATURES

The bacterial adherent characteristics of two pathogens (Salmonella enterica, Staphylococcus aureus) on the surface of polystyrene were investigated under a fluctuating temperature regime and different nutrient levels (trypticase soy broth). Bacterial adhesions were evaluated by the optical density value of bacterial cells stained with 0.1 % (w/v) of crystal violet solution. Under constant temperature conditions at 5 and 30°C, the adherent potentials of both S. enterica and S. aureus were stable at the end of incubation (5 days). Under a fluctuating temperature regime, the cell adhesion potentials were changed with the period of incubation. The adhesions of both pathogens were considerably increased by rapid temperature elevation from 5 to 30°C, while approximately twice the optical density value of cell adhesion of S. enterica was observed on the polystyrene surface compared with constant conditions. Transferring the sample tube to 5°C after fluctuation from 5 to 30°C led to considerable cell detachment of S. enterica by the end of incubation. It was probable that S. enterica cells used in this study was extremely sensitive to environmental variation, consequently cell adhesion and release could be observed under fluctuating temperature conditions. Meanwhile, stable adhesion of S. aureus cells was observed at 5°C after temperature fluctuations from 5 to 30°C.

Photodegradation of crystal violet in TiO 2 suspensions using UV–vis irradiation from two microwave-powered electrodeless discharge lamps (EDL -2): Products, mechanism and feasibility

Aqueous crystal violet (CV) solutions containing P25–TiO 2 photocatalyst were irradiated with ultraviolet–visible (UV–vis) light from two microwave-powered electrodeless discharge lamps (EDL -2). The results demonstrated that approximately 94.4% of CV was effectively removed after 3 min of irradiation, with a pseudo-first order kinetic constant of 0.838 min −1. According to 32 kinds of products, a five-step degradation pathway of CV was proposed. Further investigations showed that (1) three kinds of N-demethylated products and 4-dimethylaminobenzophenone (DLBP) were the main intermediates; (2) malachite green (MG) and leuco-crystal violet could not be generated by N-demethylation and phototransformation reactions, respectively; (3) bis(4-(dimethylamino)phenyl)methanone preferentially generated via decomposition of the conjugated structure of CV could be further N-demethylated into DLBP. Moreover, the unique degradation pathways of CV and MG were ascribed to the different substituents on the conjugated structures. Additionally, the cost and kinetic constant of different processes was also evaluated, and the results indicated the feasibility of this method for treatment of CV in field situations.

Studies on Catalytic Activity of Nanostructure Mn2O3 Prepared by Solvent-thermal Method on Degrading Crystal Violet

Nanostructure manganese oxide shows very good catalytic activity in waste water treatment of dyeing industry. A few nano manganese oxides are prepared through different methods, Their catalytic degradation property of dyeing material (crystal violet solution) is tested with H2O2 as oxidizer. Besides, the influence of other parameters are also studied, including catalyst dosage, H2O2 dosage and catalyst circulation. After reaction of 60 minutes, degradation of crystal violet can reach over 99% for most catalyst samples.

Tungstate ion resonance Rayleigh scattering method for determination of basic triphenylmethane dyes

In a pH 4.2–6.0 HAc-NaAc buffer medium, the resonance Rayleigh scattering intensities of separate basic triphenylmethane dyes, such as methyl violet (MV), ethyl violet (EV), crystal violet (CV), methyl green (MeG), iodine green (IG), malachite green (MG), light green (LG), and tungstate ion solution, are very weak, but when these cationic dyes react with the tungstate ion (WO4 2−) to form ion-association complexes, their RRS are enhanced sharply and new RRS spectra appear. The reaction products of methyl violet, ethyl violet, and crystal violet with WO4 2− have similar spectral characteristics and there are two strong RRS peaks at 330 nm and 560 nm. The reaction products of methyl green, iodine green, malachite green, light green with WO4 2− have similar spectral characteristics and there are three RRS peaks at about 335 nm, 450 nm and 580 nm. The sensitivities of seven kinds of reaction products show a sequence of malachite green>light green>crystal violet>ethyl violet>methyl green>iodine green>methyl violet. The linear ranges and detection limits of the above seven systems are 0.06–2.78 μg mL−1 and 18.1 ng mL−1 (MG), 0.08–4.83 μg mL−1 and 22.6 ng mL−1 (BG), 0.10–4.90 μg mL−1 and 31.4 ng mL−1 (CV), 0.14–2.95 μg mL−1 and 40.5 ng mL−1 (EV), 0.17–3.70 μg mL−1 and 50.2 ng mL−1 (MeG), 0.22–5.70 μg mL−1 and 67.1 ng mL−1 (IG), and 0.25–7.30 μg mL−1 and 76.3 ng mL−1 (MV). A sensitive, simple and fast RRS method for the determination of basic triphenylmethane dyes using the tungstate ion as the probe has been developed. The method is applicable to the determination of malachite green residues in fish flesh.