The effect of propolis on the bond strength of composite resin to enamel after intracoronal bleaching with different bleaching agents.

This study evaluated the effect of propolis as an antioxidant agent on bond strength to enamel after intracoronal bleaching. A total of 160 incisors were endodontically treated. Sixteen teeth were served as control, and the remaining teeth were randomly divided into three main groups according to the bleaching agent used; group 1: Sodium perborate (SP); group 2: Carbamide peroxide (CP); group 3: Hydrogen peroxide (HP). After bleaching, the samples were divided into three subgroups; subgroup A: no antioxidant agent application, subgroup B: sodium ascorbate (SA), subgroup C: propolis (PP). After the antioxidant agents application, the sample's surfaces were washed and dried. After adhesive application, composite resin cylinders were applied to enamel surfaces using tygon tubes and a shear bond strength test was performed. The use of PP significantly decreased the bond strength of composite resin to the enamel (p < 0.05). Using propolis as an antioxidant agent adversely affects the bond strength to enamel after intracoronal bleaching.

Effects of Two In-Office Bleaching Agents with Different Compositions on the Bond Strength to Enamel.

This study evaluates the effect of two in-office bleaching agents with different compositions on the bond strength to enamel surface. Fifty bovine teeth were divided into five groups (n = 10 teeth per group), according to the bleaching agent used and the time elapsed to perform the restorative procedures: restorative procedures performed without bleaching (control group); bleaching with 35% hydrogen peroxide (HP), with restorative procedures 24 hours or 7 days after bleaching (HP/24h and HP/7d groups, respectively); and bleaching with 35% HP with calcium compost, with restorative procedures 24 hours or 7 days after bleaching (HP AutoMixx/24h and HP AutoMixx/7d groups, respectively). The specimens were stored at 37°C in artificial saliva. Restored teeth were submitted to a micro-shear bond strength test. The specimens were analyzed using a stereoscope to determine the fracture pattern, classified as adhesive, cohesive, or mixed. The results of the bond strength test were evaluated by analysis of variance, with significance set at P < .05. The groups showed similar bond strength values without significant difference among them (P > .05). There was a predominance of the adhesive-type fracture pattern in all groups. The bleaching agents with different compositions showed similar bond strength values when the restoration was performed 24 hours and 7 days after bleaching, and the results were similar to the control group.

The Optimization of Extraction Process, Antioxidant, Whitening and Antibacterial Effects of Fengdan Peony Flavonoids.

Flavonoids have important biological activities, such as anti-inflammatory, antibacterial, antioxidant and whitening, which is a potential functional food raw material. However, the biological activity of Fengdan peony flavonoid is not particularly clear. Therefore, in this study, the peony flavonoid was extracted from Fengdan peony seed meal, and the antioxidant, antibacterial and whitening activities of the peony flavonoid were explored. The optimal extraction conditions were methanol concentration of 90%, solid-to-liquid ratio of 1:35 g:mL, temperature of 55 °C and time of 80 min; under these conditions, the yield of Fengdan peony flavonoid could reach 1.205 ± 0.019% (the ratio of the dry mass of rutin to the dry mass of peony seed meal). The clearance of Fengdan peony total flavonoids to 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical, hydroxyl radical and 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) free radical could reach 75%, 70% and 97%, respectively. Fengdan peony flavonoid could inhibit the growth of the Gram-positive bacteria. The minimal inhibitory concentrations (MICs) of Fengdan peony flavonoid on S. aureus, B. anthracis, B. subtilis and C. perfringens were 0.0293 mg/mL, 0.1172 mg/mL, 0.2344 mg/mL and 7.500 mg/mL, respectively. The inhibition rate of Fengdan peony flavonoid on tyrosinase was 8.53-81.08%. This study intensely illustrated that the antioxidant, whitening and antibacterial activity of Fengdan peony total flavonoids were significant. Fengdan peony total flavonoids have a great possibility of being used as functional food materials.

Disinfection of gloved hands during the COVID-19 pandemic.

BACKGROUND: Disinfection of gloves can be used during a pandemic situation when performing various procedures on the same patient or when removing personal protective equipment. If performing glove disinfection, there is a need to check the compatibility of gloves with the disinfectant product used. AIM: To test the resistance of nitrile gloves to various disinfectant solutions. METHODS: One hundred percent powder-free nitrile gloves, composed of nitrile butadiene rubber compounds, were exposed to various disinfectants to analyse resistance. The seven most commonly used disinfectant solutions in the healthcare field were selected for testing. The effects of each disinfectant were analysed in comparison with the control group (untreated glove). For tensile testing, the thickness of each test specimen was measured with a micrometer. FINDINGS: Bleach solution decreased the breaking load of gloves, although to a lesser extent than disinfectants that contained ethanol. CONCLUSION: Disinfectants that contain alcohol decrease the breaking load of nitrile gloves.

Color consistency in the appearance of bleached fabrics.

Human observers are remarkably good at perceiving constant object color across illumination changes. However, there are numerous other factors that can modulate surface appearance, such as aging, bleaching, staining, or soaking. Despite this, we are often able to identify material properties across such transformations. Little is known about how and to what extent we can compensate for the accompanying color transformations. Here we investigated whether humans could reproduce the original color of bleached fabrics. We treated 12 different fabric samples with a commercial bleaching product. Bleaching increased luminance and decreased saturation. We presented photographs of the original and bleached samples on a computer screen and asked observers to match the fabric colors to an adjustable matching disk. Different groups of observers produced matches for original and bleached samples. One group of observers were instructed to match the color of the bleached samples as they were before bleaching (i.e., compensate for the effects of bleaching); another, to accurately match color appearance. Observers did compensate significantly for the effects of bleaching when instructed to do so, but not in the appearance match condition. Results of a second experiment suggest that observers achieve color consistency, at least in part, through a strategy based on local spatial differences within the bleached samples. According to the results of a third experiment, these local spatial differences are likely to be the perceptual image cues that allow participants to determine whether a sample is bleached. When the effect of bleaching was limited or uniformly distributed across a sample's surface, observers were uncertain about the bleaching magnitude and seemed to apply cognitive strategies to achieve color consistency.

Evaluation of the effect of fluorinated tooth bleaching products using polarized Raman microscopy and particle induced gamma-ray emission.

In this in vitro study, the effect of the application of tooth bleaching products in human enamel was evaluated using polarized Raman microscopy, particle induced gamma-ray emission (PIGE) and Vickers Hardness test. Due to their acidic nature, teeth whitening products are associated with changes in enamel mineralization. Consequently, products have appeared in the market that promote the incorporation of fluorine in order to decrease the solubility of the hydroxyapatite in enamel and prevent demineralization. This way, four commercial products with different active principle concentrations: 16% carbamide peroxide (Opalescence PF® and VivaStyle®) or 6% hydrogen peroxide (Opalescence Go PF® and VivaStyle Paint On®) and presence or not of fluorine were compared. The information on the crystalline state of the enamel was provided by the determination of the depolarization ratio of the symmetric stretching band of phosphate (at 959 cm-1). Furthermore, the content and uptake of F was evaluated using PIGE in the two fluorinated products as well as in one negative control group. In order to evaluate the microhardness of enamel by means of Vickers test, another group of polished samples was prepared (using Opalescence PF®) and evaluated. Conversely to what could be expected, the obtained results determined a statistically significant decrease of depolarization ratio, leading to an increase of mineralization after the application of the bleaching products, except for VivaStyle®. For this group, no significant variation was obtained before-after treatment, most likely due to the acidity of the product (pH = 5.8). Additionally, an increase of concentration of F in the dental tissues was determined for the fluorinated products. On the other hand, enamel polishing, required for the application of the Vickers test, led to increased susceptibility to erosion, resulting in decreased hardness and an increased enamel depolarization ratio.

Effects of 16% Carbamide Peroxide Bleaching on the Surface Properties of Glazed Glassy Matrix Ceramics.

OBJECTIVE: To determine the influence of the home bleaching agent, Opalescence PF, on the surface roughness and microhardness of glazed glassy matrix CAD-CAM ceramics. Materials and Methods. The 28 sintered leucite- and lithium disilicate-reinforced ceramic specimens (IPS Empress CAD and IPS e.max CAD) were divided into control and bleached groups. The home bleaching agent was applied to specimens of bleached groups for 7 days. The surface roughness and microhardness of all specimens were measured. A scanning electron microscope was used to evaluate the surface properties. The data were statistically analyzed by two-way ANOVA. RESULTS: The control e.max CAD showed the lowest surface roughness values. For both Empress and e.max CAD, surface roughness was significantly higher for the bleached group (p < 0.05). No significant differences in microhardness were observed. CONCLUSIONS: According to our study, patients should be careful when using home bleaching agents because whitening agents can affect the mechanical properties of full ceramic restorations like e.max CAD and Empress CAD. Ceramic polishing may be required in clinical situations where ceramic restorations are accidentally exposed to bleaching gels.

Preventing Viral Contamination: Effects of Wipe and Spray-based Decontamination of Gloves and Gowns.

We conducted a laboratory simulation to evaluate the contamination of environmental surfaces when using wipe vs spray methods of personal protective equipment (PPE) decontamination. We did not observe any environmental contamination with the bacteriophage MS-2 when bleach solution spray or wipes were used for PPE disinfection.

Size-dependent whitening activity of enzyme-degraded fucoidan from Laminaria japonica.

Fucoidan from Laminaria japonica is a kind of sulfate polysaccharide with high molecular weight (MW) and broad bioactivities. This study was performed to investigate the relationship between MW and whitening activity of fucoidan and to exploit a novel functional ingredient for whitening cosmetics. High sulfate content fucoidan was enzymic degraded by Flavobacterium RC2-3 produced fucoidanase. Two hours were enough for the enzyme degradation to achieve degraded fucoidan with favorable tyrosinase inhibitory ability. The whitening activity of different MW fucoidan fractions were evaluated by their tyrosinase inhibitory ability, antioxidant activity and cellular melanogenesis inhibitory ability. Results showed that in the MW range above 5 kDa, the smaller MW of fucoidan were related to the better whitening activity. The fucoidan fraction with the MW between 5-10 kDa, presented the best tyrosinase inhibitory activity (62.0%), antioxidant activity (48.3%) and excellent anti-melanogenesis ability in B16 cells, which could be applied as the whitening factor in cosmetics development.

Decontamination of 70 foster family homes exposed to Microsporum canis infected cats: a retrospective study.

BACKGROUND: Dermatophytosis is a superficial fungal skin disease of animals. A key part of treatment is cleaning and disinfection of the environment to prevent false-positive results due to fomite carriage. Furthermore, there is a perception in the lay literature that decontamination of homes is difficult or impossible. CLINICAL SUMMARY: Data from a 10 year period identified 70 foster family homes where Microsporum canis infected cats had lived for varying periods of time. Mechanical debris was removed from the rooms housing the cats, the areas cleaned with over-the-counter household detergents, rinsed and hard surfaces disinfected with 1:100 concentration household bleach or accelerated hydrogen peroxide. Thirty-eight homes were completely decontaminated after one cleaning post removal or cure of the cat. Of the remaining homes, decontaminated was achieved after one (n=28), two (n=2) or three (n=1) additional cleanings. Complete decontamination was not possible in one home; the foster family was admittedly noncompliant. There was no evidence of disease transmission to other animals or people. CONCLUSIONS: Environmental decontamination is not difficult in homes exposed to M. canis and can be accomplished with established procedures.

L-765,314 Suppresses Melanin Synthesis by Regulating Tyrosinase Activity.

Although melanin production is a key self-defense mechanism against ultraviolet radiation (UVR)-induced skin damage, uneven or excessive deposition of melanin causes hyperpigmentary disorders. Currently available whitening agents are unsatisfactory because of issues with efficacy and safety. To develop more effective depigmenting agents, we performed high-throughput melanin content assay screening using the B16F10 melanoma cell line and identified L-765,314 as a drug that suppressed melanin production in cultured melanocytes in a dose-dependent manner as well as cAMP- or 12-O-tetradecanoylphorbol 13-acetate (TPA)-stimulated melanin production without cytotoxicity. Interestingly, melanogenic gene expression was not altered by L-765,314. Rather, diminished melanin production by L-765,314 appeared to be caused by downregulation of tyrosinase activity via inhibition of protein kinase C (PKC). Because L-765,314 did not show any adverse effect in melanocytes, altogether our data suggest that L-765,314 could be a potential therapeutic candidate for skin hyperpigmentary disorders and further discovery of selective inhibitors targeting PKC might be a promising strategy for the development of depigmenting agents to treat hyperpigmentary disorders.

Cytological Effects of Bleaching Agent (Quneex) on Plant Cells and Plant DNA.

BACKGROUND AND OBJECTIVE: There have been a number of reported drawbacks and efficacy issues regarding the use of bleaching agents in the plant industry. This study was conducted to determine the cytological effects of the bleaching agent (Quneex) on the plant cells and plant DNA using the Allium cepa assay. MATERIALS AND METHODS: It was subjected sixteen root meristems of A. cepa to different concentrations of the bleaching agent (0.1, 0.2, 0.3, 0.4 and 0.5%) with different periods of time (6, 12 and 24 h). Recovery was done for 6, 12 and 24 h after exposure. RESULTS: The mitotic index significantly decreased with time and also decreased with increase in the concentration of the bleaching agent. Abnormal chromosomal changes reflecting mutagenesis including stickiness, laggards, bridges, C-metaphase, star-metaphase, binucleation, polyploidy, disturbance and multinucleation were observed in the different concentrations and periods of time. After recovery, a slow increase in the mitotic index was observed. All treatments with or without recovery for 12 and 24 h resulted in reduction in the amount of DNA. CONCLUSION: Bleaching agents similar to Quneex containing sodium hypochlorite have mutagenic properties that can be potentially hazardous to the environment and also to humans. Thus, there is a need to regulate the use and disposal of such chemicals into the environment particularly to the sewers, to prevent contamination of potable water, plant and biodiverse aquatic animals.

Characterization of diverse homoserine lactone synthases in Escherichia coli.

Quorum sensing networks have been identified in over one hundred bacterial species to date. A subset of these networks regulate group behaviors, such as bioluminescence, virulence, and biofilm formation, by sending and receiving small molecules called homoserine lactones (HSLs). Bioengineers have incorporated quorum sensing pathways into genetic circuits to connect logical operations. However, the development of higher-order genetic circuitry is inhibited by crosstalk, in which one quorum sensing network responds to HSLs produced by a different network. Here, we report the construction and characterization of a library of ten synthases including some that are expected to produce HSLs that are incompatible with the Lux pathway, and therefore show no crosstalk. We demonstrated their function in a common lab chassis, Escherichia coli BL21, and in two contexts, liquid and solid agar cultures, using decoupled Sender and Receiver pathways. We observed weak or strong stimulation of a Lux receiver by longer-chain or shorter-chain HSL-generating Senders, respectively. We also considered the under-investigated risk of unintentional release of incompletely deactivated HSLs in biological waste. We found that HSL-enriched media treated with bleach were still bioactive, while autoclaving deactivates LuxR induction. This work represents the most extensive comparison of quorum signaling synthases to date and greatly expands the bacterial signaling toolkit while recommending practices for disposal based on empirical, quantitative evidence.

CnoX Is a Chaperedoxin: A Holdase that Protects Its Substrates from Irreversible Oxidation.

Bleach (HOCl) is a powerful oxidant that kills bacteria in part by causing protein aggregation. It inactivates ATP-dependent chaperones, rendering cellular proteins mostly dependent on holdases. Here we identified Escherichia coli CnoX (YbbN) as a folding factor that, when activated by bleach via chlorination, functions as an efficient holdase, protecting the substrates of the major folding systems GroEL/ES and DnaK/J/GrpE. Remarkably, CnoX uniquely combines this function with the ability to prevent the irreversible oxidation of its substrates. This dual activity makes CnoX the founding member of a family of proteins, the "chaperedoxins." Because CnoX displays a thioredoxin fold and a tetratricopeptide (TPR) domain, two structural motifs conserved in all organisms, this investigation sets the stage for the discovery of additional chaperedoxins in bacteria and eukaryotes that could cooperate with proteins from both the Hsp60 and Hsp70 families.

Preparation of antimicrobial and hemostatic cotton with modified mesoporous particles for biomedical applications.

N-halamine polymers have been successfully attached surfaces of mesoporous materials. The modified mesoporous materials have been applied on the modification of cotton. Soaking in household bleach, the coated cotton shows good antimicrobial efficacy against S. aureus and E. coli O157:H7. The chlorinated samples could completely inactivate 100% S. aureus within 10 min, and 99.99% E. coli O157:H7 within 30 min. The chlorinated sample had better platelet adhesion and red blood cell cohesion than the control sample. The blood clotting index and fluid absorptive property of the samples enhanced after coating with modified mesoporous materials, indicating that the coated sample can prevent wound infection from bacteria and control hemorrhaging simultaneously. The coating of the modified mesoporous materials and N-halamines on cotton has not affect the bioactivity of cotton in the simulated body fluid. The active chlorine of the coated sample decreased 30% after soaking in the whole blood for 1 h. Considering the good antimicrobial efficacy against microorganisms and hemostasis property in blood control of the prepared materials, they have potentials for biomedical applications in wound dressing.

Dentin bond strength and nanoleakage of the adhesive interface after intracoronal bleaching.

This study evaluated dentin bond strength (BS) and nanoleakage of non- and pre-etched dentin immediately (T0 ,), 7 days (T7 ), and 14 days (T14 ) after bleaching. Bovine incisors (150) were selected and half of them submitted to intrapulpal dentin etching (e). Non- and pre-etched dentin were subjected to the following (n = 15): no bleaching/control (C); 35% carbamide peroxide (CP); 35% hydrogen peroxide (35% HP); 25% hydrogen peroxide (25% HP); and sodium perborate (SP). Bleaching agents were applied to the pulp chamber four times within a 72-h interval. Afterwards, pulp chamber dentin was prepared for the BS test at different evaluation times (n = 5): T0 , T7 , and T14 . Composite blocks were built on pulp chamber and sectioned in slices. Slices were reduced to an hour-glass shape with a cross-sectional area of 0.8 mm2 and submitted to microtensile BS test. Two additional specimens for each group were prepared for nanoleakage evaluation by transmission electron microscopy (TEM). Results were analyzed by ANOVA (two-way) and Dunnett's test (p < .05). BS decreased immediately after intracoronal bleaching for both sound and pre-etched dentin (p < .05). At T14 , the BS of non-etched bleached dentin increased for all groups, whereas the pre-etched SPe group presented BS similar to the Ce. Nanoleakage within the hybrid layer was perceptible immediately after bleaching, although a decrease in nanoleakage was observed for all groups at T14 . Adhesive restorations should be performed 7-14 days after bleaching, according to the bleaching agent used. Intracoronal bleaching should be performed preferably with sodium perborate if previous dentin etching is applied.

Two-Center Evaluation of Disinfectant Efficacy against Ebola Virus in Clinical and Laboratory Matrices.

Ebola virus (EBOV) in body fluids poses risk for virus transmission. However, there are limited experimental data for such matrices on the disinfectant efficacy against EBOV. We evaluated the effectiveness of disinfectants against EBOV in blood on surfaces. Only 5% peracetic acid consistently reduced EBOV titers in dried blood to the assay limit of quantification.

Effect of the type and number of washes in the efficacy of long lasting insecticidal nets for Aedes aegypti control in Girardot, Colombia.

INTRODUCTION: The use of long lasting insecticidal materials has shown promising results in the control of Aedes aegypti. OBJECTIVE: To evaluate the efficacy of long-lasting insecticidal nets (PermaNet®) for Aedes aegypti control after three washing treatments in the city of Girardot, Colombia. MATERIALS AND METHODS: Standard bioassays were conducted with the nets following the World Health Organization protocols using wild A. aegypti after three washing treatments: (1) Detergent powder, (2) detergent powder and bleach, and (3) bar soap, until completing 20 washes. RESULTS: The type and number of wash treatments had a significant effect on net efficacy. Greater effects in the insecticide bioavailability were seen for the bar soap treatment. After six washes, mortality decreased by 50% (25/50), vs 66% (33/50) for the detergent powder and 84% (42/50) for the detergent powder and bleach treatments. Regarding the number of washes, the bar soap treatment reduced the efficacy to 68% after only three washes. CONCLUSION: The effectiveness of long-lasting insecticidal nets (PermaNet 2.0) for A. aegypti control varied in relation to the treatment and number of washes. The bar soap treatment resulted in the greatest reduction of mortality. Further studies on insecticidal reductions are needed under local conditions.

Staphylococcus aureus extracellular vesicles (EVs): surface-binding antagonists of biofilm formation.

The prevalence of Staphylococcus aureus worldwide as a nosocomial infectious agent is recognized but the reason behind the spread of this bacterium has remained elusive. Here, we hypothesized that the communication of S. aureus might benefit from it blocking other bacteria from establishing themselves on the surface. This was found to be the case for several pathogens as the S. aureus supernatant curtailed their ability to form biofilms. Subsequent analyses using Acinetobacter baumannii as a model found this effect is primarily mediated by S. aureus' extracellular vesicles (EVs), which bound to the polystyrene surface. We found the EV-treated surfaces were significantly more hydrophilic after EV treatment, a condition that made it difficult for A. baumannii to initially adhere to the polystyrene surface and reduced its resulting biofilm by up to 93%. Subsequent tests found this also extended to several other bacterial pathogens, with a 40-70% decrease in their biofilm mass. The S. aureus EVs and their activity still remained after the surface was washed with 10% bleach, while the use of ethylenediaminetetraacetic acid (EDTA) removed both the EVs from the surface and their activity.

Efecto del tipo y del número de lavados en la eficacia de mosquiteros tratados con deltametrina de larga duración para el control de Aedes aegypti en Girardot, Colombia / Effect of the type and number of washes in the efficacy of long lasting insecticidal nets for Aedes aegypti control in Girardot, Colombia

Resumen Introducción. El uso de mosquiteros tratados con insecticida en fórmulas de larga duración ha demostrado resultados prometedores en el control de Aedes aegypti. Objetivo. Evaluar la eficacia de mosquiteros impregnados con deltametrina en una fórmula de larga duración para el control de A. aegypti en Girardot, Colombia, después de tres lavados. Materiales y métodos. Se hicieron bioensayos de eficacia de los mosquiteros contra A. aegypti silvestres después de utilizar los siguientes tres productos de lavado, siguiendo la metodología de la Organización Mundial de la Salud: detergente en polvo, detergente en polvo y blanqueador, y jabón de barra, todos utilizados hasta en 20 lavados. Resultados. El tipo de producto de lavado y el número de lavados afectaron significativamente la eficacia de los mosquiteros impregnados con deltametrina. El lavado con jabón de barra presentó el mayor efecto, pues en tan solo seis lavados la mortalidad bajó a 50 % (25/50), en contraste con 66 % (33/50 de mortalidad después del lavado con detergente en polvo y de 84 % (42/50) después del lavado con detergente y blanqueador. En cuanto al número de lavados, el jabón en barra también causó una mayor reducción de la eficacia: a 68 % con solo tres lavados. Conclusión. La eficacia de los mosquiteros impregnados con deltametrina de larga duración en el control de A. aegypti varió con el tipo de producto de lavado y el número de lavados, siendo el jabón en barra el que redujo su eficacia en mayor medida. Se requieren nuevos estudios para establecer la disminución en la concentración del insecticida entre lavados.

Abstract Introduction: The use of long lasting insecticidal materials has shown promising results in the control of Aedes aegypti. Objective: To evaluate the efficacy of long-lasting insecticidal nets (PermaNet®) for Aedes aegypti control after three washing treatments in the city of Girardot, Colombia. Materials and methods: Standard bioassays were conducted with the nets following the World Health Organization protocols using wild A. aegypti after three washing treatments: (1) Detergent powder, (2)detergent powder and bleach, and (3) bar soap, until completing 20 washes. Results: The type and number of wash treatments had a significant effect on net efficacy. Greater effects in the insecticide bioavailability were seen for the bar soap treatment. After six washes, mortality decreased by 50% (25/50), vs 66% (33/50) for the detergent powder and 84% (42/50) for the detergent powder and bleach treatments. Regarding the number of washes, the bar soap treatment reduced the efficacy to 68% after only three washes. Conclusion: The effectiveness of long-lasting insecticidal nets (PermaNet 2.0) for A. aegypti control varied in relation to the treatment and number of washes. The bar soap treatment resulted in the greatest reduction of mortality. Further studies on insecticidal reductions are needed under local conditions.