Bleaching Research Articles

Chlorine content analysis on white rice at the Pagesangan Market, Mataram City

In Indonesia, rice is a staple food consumed daily. The high purchasing power of the public for good quality rice makes this a reason for producers to add dangerous bleaching agents such as chlorine to improve the physical quality of the rice they sell. The use of unclear bleaching agents on rice that do not meet the requirements for permitted additives in food and whose concentrations exceed the threshold limits is dangerous for human health. This research aims to determine the presence of chlorine in white rice sold at the Pagesangan market. The methods used are qualitative and quantitative. Three of the five rice samples tested at the Mataram STTL Laboratory tested positive for chlorine. Chlorine levels in rice samples, sample C, were 367.4 mg/L, sample D was 275.1 mg/L, and sample E was 93.4 mg/L.

Gas-Phase and Surface-Initiated Reactions of Household Bleach and Terpene-Containing Cleaning Products Yield Chlorination and Oxidation Products Adsorbed onto Indoor Relevant Surfaces.

The use of household bleach cleaning products results in emissions of highly oxidative gaseous species, such as hypochlorous acid (HOCl) and chlorine (Cl2). These species readily react with volatile organic compounds (VOCs), such as limonene, one of the most abundant compounds found in indoor enviroments. In this study, reactions of HOCl/Cl2 with limonene in the gas phase and on indoor relevant surfaces were investigated. Using an environmental Teflon chamber, we show that silica (SiO2), a proxy for window glass, and rutile (TiO2), a component of paint and self-cleaning surfaces, act as a reservoir for adsorption of gas-phase products formed between HOCl/Cl2 and limonene. Furthermore, high-resolution mass spectrometry (HRMS) shows that the gas-phase reaction products of HOCl/Cl2 and limonene readily adsorb on both SiO2 and TiO2. Surface-mediated reactions can also occur, leading to the formation of new chlorine- and oxygen-containing products. Transmission Fourier-transform infrared (FTIR) spectroscopy of adsorption and desorption of bleach and terpene oxidation products indicates that these chlorine- and oxygen-containing products strongly adsorb on both SiO2 and TiO2 surfaces for days, providing potential sources of human exposure and sinks for additional heterogeneous reactions.

Effects of 35% Versus 10% Carbamide Peroxide At-Home Bleaching Agents with or without MI Paste Plus on Enamel Properties

This study compared the effects of 35% with 10% carbamide peroxide (CP) home used bleaching agents on enamel color change, microhardness, and surface changes in association with MI paste plus (CPP -ACPF). Forty buccal and lingual enamel samples from twenty human third molars were prepared and divided into four groups (n=10). The groups were bleached for two weeks according to different bleaching regimens as follow; G1 bleached with 10%CP, G2 bleached with 35%CP, G3 bleached with a mixture of 10%CP and MI paste plus, and G4 bleached with a mixture of 35%CP and MI paste plus. Color change was recorded with a colorimeter before and after bleaching and total color differences (ΔE*) was calculated. Vickers microhardness test was recorded for all the samples before and after treatment. One sample from each group was evaluated for surface changes by scan electron microscopy (SEM). The data were analyzed with repeated measure of variance and student's t-test at p<0.05. No significant difference in ΔE* was recorded among the four groups (p>0.05). Significant reduction in enamel microhardness was only recorded for G2 (p=0.003). SEM for G3 and G4 showed obvious mineral deposition. Similar teeth color whitening can be resulted after two weeks of bleaching with both 10%CP and 35%CP when used as recommended by the manufacturer with and without the addition of MI paste plus. Using 35%CP decreased enamel microhardness significantly, whereas MI paste plus when mixed with both bleaching agents could compensate for the microhardness reduction.

Testing the effectiveness of different wash protocols to remove body surface contaminants in invertebrate food web studies.

Molecular gut content analysis via diagnostic PCR or high-throughput sequencing (metabarcoding) of consumers allows unravelling of feeding interactions in a wide range of animals. This is of particular advantage for analyzing the diet of small invertebrates living in opaque habitats such as the soil. Due to their small body size, which complicates dissection, microarthropods are subjected to whole-body DNA extraction-step before their gut content is screened for DNA of their food. This poses the problem that body surface contaminants, such as fungal spores may be incorrectly identified as ingested food particles for fungivorous species. We investigated the effectiveness of ten methods for body surface decontamination in litter-dwelling oribatid mites using Steganacarus magnus as model species. Furthermore, we tested for potential adverse effects of the decontamination techniques on the molecular detection of ingested prey organisms. Prior to decontamination, oribatid mites were fed with an oversupply of nematodes (Plectus sp.) and postmortem contaminated with fungal spores (Chaetomium globosum). We used diagnostic PCR with primers specific for C. globosum and Plectus sp. to detect contaminants and prey, respectively. The results suggest that chlorine bleach (sodium hypochloride, NaClO, 5%) is most efficient in removing fungal surface contamination without significantly affecting the detection of prey DNA in the gut. Based on these results, we provide a standard protocol for efficient body surface decontamination allowing to trace the prey spectrum of microarthropods using molecular gut content analysis.

A REVIEW ON NATURAL SKIN LIGHTENING AGENTS

Natural bleaching agents are the natural metabolites mostly obtained from plants as well as from other natural sources implied to reduce or alter melanin production in the human body. Many natural compounds exert their efficiency as skin lightening agent, i.e., vitamin C, E and niacinamide flavonoids, phenolic compounds, arbutin, kojic acid, azelaic acid, Mulberroside F, Aloin, aloesin, Glabridin, liqriritin, N-acetyl glucosamine has found as a substantial compound obtained from a natural source and could be used reduce skin condition that causes hyperpigmetation. Natural bleaching agents could be better alternatives to synthetic bleaching agents due to their biocompatatibily to the human skin.

Heat-evolved algal symbionts enhance bleaching tolerance of adult corals without trade-off against growth.

Ocean warming has caused coral mass bleaching and mortality worldwide and the persistence of symbiotic reef-building corals requires rapid acclimation or adaptation. Experimental evolution of the coral's microalgal symbionts followed by their introduction into coral is one potential method to enhance coral thermotolerance. Heat-evolved microalgal symbionts of the generalist species, Cladocopium proliferum (strain SS8), were exposed to elevated temperature (31°C) for ~10 years, and were introduced into four genotypes of chemically bleached adult fragments of the scleractinian coral, Galaxea fascicularis. Two of the four coral genotypes acquired SS8. The new symbionts persisted for the 5 months of the experiment and enhanced adult coral thermotolerance, compared with corals that were inoculated with the wild-type C. proliferum strain. Thermotolerance of SS8-corals was similar to that of coral fragments from the same colony hosting the homologous symbiont, Durusdinium sp., which is naturally heat tolerant. However, SS8-coral fragments exhibited faster growth and recovered cell density and photochemical efficiency more quickly following chemical bleaching and inoculation under ambient temperature relative to Durusdinium-corals. Mass spectrometry imaging suggests that algal pigments involved in photobiology and oxidative stress were the greatest contributors to the thermotolerance differences between coral hosting heat-evolved versus wild-type C. proliferum. These pigments may have increased photoprotection in the heat-evolved symbionts. This is the first laboratory study to show that thermotolerance of adult corals (G. fascicularis) can be enhanced via the uptake of exogenously supplied, heat-evolved symbionts, without a trade-off against growth under ambient temperature. Importantly, heat-evolved C. proliferum remained in the corals in moderate abundance 2 years after first inoculation, suggesting long-term stability of this novel symbiosis and potential long-term benefits to coral thermotolerance.

Evaluation of Different Integrated Disease Management Approaches for Rhizome Rot of Ginger (Zingiber officinale Roscoe.) Caused by Ralstonia solanacearum (Smith.) under Field Conditions

Ginger (Zingiber officinale Roscoe.,) is a slender herbaceous perennial plant belonging to the family Zingiberaceae, medicinally important and commercial spice crop. India is the largest producer of ginger and accounts for about 1/3rd of the total world output. Ginger is grown in Kerala, Karnataka, West Bengal, Andhra Pradesh, Orissa, Arunachal Pradesh, Sikkim and other parts of India. The production of ginger is greatly influenced by diseases caused by bacteria, fungi, viruses, mycoplasma and nematodes. One of the diseases of ginger is bacterial wilt caused by Ralstonia solanacearum, which causes yield loss of up to 80 percent. A field experiment was conducted with integrated approaches to manage the ginger rhizome rot caused by R. solanacearum (Smith). The experiment was laid out with a Randomized Completely Block Design (RCBD) including nine treatments and four replications. The experiment results revealed that, rhizome treatment with Streptocycline @ 0.5 g + COC @ 3.0 g/l of water + soil application with neem cake 3q/ha followed by drenching with bleaching powder (33%) @ 2.0 g/l + Metalaxyl MZ @ 1.0 g/lit for water three times at 20 days intervals + Ginger special spray 45 DAS, starting with the initiation of the disease was significantly most effective and recorded a higher yield of 110.27 q/ha with least disease incidence of disease (14.23 %). Integrated management of rhizome rot of ginger through soil solarization revealed that, among the different treatments, the treatment treated with soil solarization + rhizome treatment with Streptocycline @ 0.5 g + Copper Oxy Chloride @ 3.0 g/lit of water + Soil application of Pseudomonas fluorescens @ 10 kg along with 25t FYM /ha recorded higher yield of 115.23 q/ha with less percent disease incidence (8.20 %).

Chemistry saving lives: using First World War Hypo helmets to avoid chlorine poisoning

Abstract A Hypo helmet is a fabric hood soaked with an aqueous solution of two sodium salts for the detoxication of chlorine that was developed during the First World War. Herein, we report on a lecture, developed for non-chemistry majors that used the Hypo helmet to highlight the physical and chemical properties of chlorine. The lecture consisted of the following three components: (1) a brief introduction to the First World War (the Chemists’ War), (2) video demonstrations of the generation of chlorine by mixing bleaching powder and hydrochloric acid and the detoxication of chlorine using a dummy Hypo helmet, and (3) students’ written impressions of the lecture. The students’ written impressions revealed two things: the lecture on chlorine and the Hypo helmet was well received, and most of the students (71 %, N = 82) did not know that chlorine was used as a poisonous gas during the First World War.

Thermo-alkali stable bacterial xylanase for deinking of copier paper

BackgroundThe bleach-boosting capability of xylanases is well-known. The use of xylanase pre-treatment before the application of chemical bleach has multiple advantages including (i) lesser use of polluting chemicals of the traditional bleaching process; (ii) less damage to the cellulosic fibers, therefore better recyclability; and (iii) better brightness of chemical bleach. The major impediment in the application is the availability of commercial enzymes that are active at the elevated temperature and pH that exist during the industrial pulping process. In the present paper, xylanase having suitability for application in deinking is reported. ResultsThe xylanase used showed high deinking potential. Optimal deinking was obtained at the xylanase dosing of 20U/g of the dried pulp at 60℃ for a treatment time of 1h. It could bring about a 50% reduction in the usage of chemical bleach that was applied after xylanase pre-treatment. The comparison of FTIR spectra showed changes in intensity without significant changes in the functional group signatures implying that there is negligible damage to the fiber strength in the xylanase pre-treatment process as compared to the chemical bleach process. ConclusionThe xylanase used in this study was effective in deinking paper pulp and can be used for bio-bleaching of recycled paper.

Dental aesthetic perception of patients submitted to activated charcoal-based bleaching agents: A randomized clinical trial

ObjectiveTo evaluate the effects of activated charcoal-based products used in two presentation forms (powder or toothpaste), compared to 10 % carbamide peroxide and conventional toothpaste on aesthetic perception and psychosocial impact before and after treatment. MethodsFifty-six participants were divided into 4 experimental groups (n = 14). Activated charcoal-based powder (PW); Activated charcoal-based dentifrice (AC); Conventional fluoride toothpaste (CD) and 10 % carbamide peroxide (CP). All products were used for 14 days. Psychosocial impact on dental esthetics (PIDAQ), oral health impact profile (OHIP- Esthetics) and orofacial esthetics scale (OES) questionnaires were applied before and after treatment. Descriptive and exploratory data analyses were performed and analyzed using linear mixed models for repeated measures over time considering significance level of α = 0.05. ResultsFor PIDAQ, the CP group showed significant decrease in psychological impact, aesthetic perception domains and overall score, while in the PW group, there was only a significant decrease in the psychological impact domain. Decrease in OHIP was observed for the functional limitation domain scores for treatments with CP and PW, in the psychological discomfort domain, decrease was observed for all groups, while for the OES questionnaire, significant increase in the color domain was observed for the CP group. ConclusionActivated charcoal-based products showed lower scores in all questionnaires when compared with carbamide peroxide; thus, charcoal-based products promoted lower impact on quality of life and aesthetic perception. Clinical relevanceIn this randomized clinical trial, charcoal-based OTC products had inferior quality of life and aesthetic perception results compared to conventional carbamide peroxide bleaching.

Porous 3D Printed System for Synergistic Tandem Water Cleaning‐Energy Generation

AbstractNon‐availability of fresh water is the dire consequence of rapid industrialization and the unregulated discharge of industrial effluents. In an attempt to recover water from highly contaminated industrial wastewater, researchers have relied on developing various materials that can treat polluted water efficiently and sustainably. 3D printed materials have proved to be an emerging technology in water treatment. 2D materials have recently enhanced filter technology due to their morphological properties. This study focuses on removing salinity and organic dyes utilizing 2D Gadolinium telluride (Gd2Te3 ) coated 3D printed (2D@3DP) complex architecture. The 2D@3DP structure can potentially increase the contact time of adsorbed saline water due to its complex architecture and can remove ≈52% salinity from brackish water. Furthermore, methylene blue (MB) and Methyl Orange (MO) removal efficiencies are ≈69% and 45%, respectively. Spectroscopic and microscopic results confirm the adsorption of negatively charged chlorine ions on a positively charged 2D surface. The removal of bleaching powder is also tested for real‐life applications, and ≈20% of the bleaching powder is adsorbed. Moreover, the 2D@3DP device exhibits an electrical signal due to impinging sodium chloride droplets from different heights, making it a sustainable solution to address water pollution.

Effect of bleaching treatments on the adhesion of orthodontic brackets: a systematic review

BackgroundNowadays bleaching procedures have gained popularity in orthodontic patients. Peroxide and Carbamide acids are the common agents which are used in in-office and at home bleaching techniques.Consequently, the Bonding adhesion to the enamel can be influenced by the orthodontic phase and the residual peroxide might interfere with the polymerization and the adhesion of the brackets.Frequent debonding of the brackets from teeth after the bleaching procedure could cause the lengthening of the therapy and promote irregularities on enamel surface derived from an additional bonding phase of the brackets.The aim of this systematic review is to appraise the influence regarding the effect of the bleaching procedure on the bond strength of orthodontic brackets.MethodsAn electronic database search was performed. Search terms included: bleaching, brackets, adhesion; data were extracted and summarized. Risk of bias was assessed using the Chocrane risk of bias tool, adapted for in vitro studies.ResultsA total of 8689 articles were screened and 11 studies met the inclusion criteria of this systematic review.1000 teeth of human and bovine origin were analyzed for the shear bond strength (SBS) of stainless and ceramic brackets after the bleaching treatments. All the authors divided the groups in different subgroups with different bleaching agents and in different concentration.The SBS value allowed to demonstrate the necessity to delay the bonding of the brackets for two weeks after a bleaching treatment and its improvement when tooth mousse or antioxidants agents are used.ConclusionsThe SBS values and the delay of the bonding procedure must be considered in dental practice and clinical strategies are necessary in order to avoid drawbacks which could cause the debonding of the brackets after bleaching due to the alterations of the dental substrate, thus interfering with the orthodontic treatments.

A Titration Method for Standardization of Aqueous Sodium Chlorite Solutions Using Thiourea Dioxide.

Accurate and cost-effective methods for the analysis of oxychlorine compounds in water are critical to modern chlorine-based water treatment. With alternatives to elemental chlorine and hypochlorite bleaches growing in popularity, simple quantification methods for the disinfectant chlorine dioxide (ClO2) in water, as well as chlorite (ClO2-) and chlorate (ClO3-), which are commonly used precursors in ClO2 generation, are required. However, currently, regulated standard methods require specialized equipment and do not effectively discriminate between molecular and ionic species. In this contribution, we present a simple titration-based method for chlorite determination in water using commercially available and easy-to-handle reagents. Specifically, chlorite is reduced with a slight excess of thioureadioxide (TUD). The remaining reductant is then back-titrated against a known amount of potassium permanganate, affording calculatable chlorite concentrations through measured consumption of a reductant and a clear visual endpoint upon accumulation of excess KMnO4. Straightforward methods for chlorite standardization with reasonable error and accuracy for field and/or lab application have the potential to greatly enhance quality assurance and therefore assist in resource deployment in water treatment.

Chemical decontamination of methamphetamine and ephedrine using household hypochlorite bleach

Hypochlorite bleach is an easily accessible, commonly used cleaning product. Methamphetamine and ephedrine hydrochloride react rapidly with 3.5 g/L (1:8 dilution of a commercial household bleach) and 21 g/L (2:1 dilution) solutions of sodium hypochlorite bleach in water, with each reaction being complete within 5 min of mixing. The major methamphetamine reaction product was identified as N-chloromethamphetamine which was reliably quantified by dechlorination using a sulfite quench prior to sample extraction and analysis by gas chromatography – mass spectrometry (GC–MS). The initial product from ephedrine was benzaldehyde, and this then formed benzoic acid as a second-generation product in the 3.5 g/L sodium hypochlorite bleach solution.N-Chloromethamphetamine was observed to persist in solution for several hours with minor formation of benzaldehyde and N-chloro-1-phenylpropan-2-imine, a proposed second-generation product from N-chloromethamphetamine, also detected. Assessment of further N-chloramine reaction products will aid in our ability to estimate exposure risks to those attempting drug remediation using hypochlorite bleach. These observed products can also be used as potential forensic markers of the use of a property for illicit activity if bleach has been used in an attempt to decontaminate the location.

The Effect of Bleaching Agents on Color Change in Different Section Shapes in Beech And Fir Woods

Aim of study: It is an investigation of the effects of bleaching processes on the color change in the wood of tree species. Tree species Eastern Beech (Fagus Orientalis Lipsky.) and Eastern Black Sea Fir (Abies Nordmanniana subsp.) were used in the study. Sodium hydroxide-hydrogen peroxide, oxalic acid, peracetic acid diluted 1/3, peracetic acid diluted 1/6 were used as bleaching agents. Trial samples were prepared in accordance with standards and color change measurements were made.
 Area of study: Surface treatments on wooden materials
 Material and methods: In the study, two wood species and one varnish type were used; Color changes were tested by applying various bleaches to the wooden material by rubbing method.
 Main results: As a result of the study, differences were observed in all cross-section shapes in beech wood bleaching measurements with 1/6 diluted peracetic acid, and differences were observed in cross-section shapes in fir wood bleaching measurements. The best bleaching of fir wood was achieved with peracetic acid.
 Main results: As a result of the study, differences were observed in all cross-section shapes in the beech wood bleaching measurements with 1/6 diluted peracetic acid, and in the cross-section shapes in the fir tree bleaching measurements. The best bleaching of fir wood was achieved with peracetic acid.
 Highlights: The bleaching process allows the wooden material to easily acquire a homogeneous color. Since the cell arrangements are different in different cross-sectional shapes, the bleaching rates are different from each other. While there is not much difference in the color changes in the wood material when bleached with oxalic acid, the samples are bleached as a result of bleaching with sodium hydroxide-hydrogen peroxide and peracetic acid. Significant changes have occurred in color changes. The reason for this difference is due to the different degrees of corrosion of bleaching agents.

S2937 The Effects of Large Volume Ingestion of Concentrated Household Bleach

S2937 The Effects of Large Volume Ingestion of Concentrated Household Bleach

Determination of color characteristics of some wood species treated with bleaching chemicals

With the application of bleaching treatments, the color of the wood material changes. When different bleaching agents are applied to the same wood, different results are likely to be obtained. In this study, wood species doussié (Afzelia africana), iatandza (Albizia ferruginea), merbau (Intsia bijuga (Colebr.) O. Kuntze), mahogany (Swietenia mahagoni L.), and hornbeam (Carpinus betulus L.) along with one and two component (B-One-C and B-Two-C) wood bleaching chemicals were applied to the wood material surfaces with sponge technique. Then, color parameters (ho: hue angle, a*: red color tone, b*: yellow color tone, C*: chroma, and L*: lightness) were determined on bleached and unbleached materials. According to the results obtained, B-One-C application increased ho, a*, b*, C*, and L* values in all wood species. The highest ∆E* values were determined in mahogany, doussié, hornbeam, and merbau wood species treated with B-Two-C. The chemicals used in the study showed different results on the same wood.

The effect of in-office bleaching agents on the Vickers hardness and surface topography of polished and unpolished CAD/CAM composite materials

In-office bleaching, using hydrogen peroxide, is effective to remove dental enamel stains. However, bleaching agents can deteriorate surface properties of CAD-CAM materials. This in vitro study aimed to investigate the effect of in-office bleaching agents on Vickers hardness and surface topography of polished and unpolished dental CAD-CAM composite materials (Grandio blocs, Lava Ultimate, BRILLIANT Crios, Cerasmart), and a polymer-infiltrated ceramic network block (Vita Enamic). The specimens were randomly divided into two groups: unpolished or polished. The micro-hardness and surface topography of each group were measured before bleaching, after a 60 min bleaching period, and 24-h and one-month post-bleaching. In-office bleaching significantly influenced the Vickers hardness of both the polished and unpolished CAD/CAM composite blocks, with Vita Enamic exhibiting the least hardness stability among all groups. Furthermore, in-office bleaching significantly influenced the surface roughness of unpolished CAD/CAM composite blocks. There was a significant difference in hardness reduction between the polished and unpolished specimens for most of the investigated materials at different time points. The bleaching did not influence the surface roughness of the investigated polished group, except for Vita Enamic and Lava Ultimate. However, it did influence the surface roughness of the investigated materials in the unpolished group.

Inflammatory parameters and color alterations of dental bleaching in patients wearing fixed orthodontic appliance: a randomized clinical trial

BackgroundMany orthodontic patients request dental bleaching during orthodontic treatment to achieve a faster aesthetic resolution, however, no attention has been paid to the inflammatory processes that can occur when both therapies are indicated together. So, this clinical trial evaluated the inflammatory parameters and color alterations associated with dental bleaching in patients wearing a fixed orthodontic appliance.MethodsThirty individuals aged between 18 and 40 years were equally and randomly allocated into three groups: FOA (fixed orthodontic appliance), BLE (dental bleaching), and FOA + BLE (fixed orthodontic appliance + dental bleaching). The orthodontic appliances and the bleaching procedures were performed in the maxillary premolars and molars. For dental bleaching a 35% hydrogen peroxide was used. The gingival crevicular fluid (GCF) and nitric oxide (NO-) levels were evaluated at different time-points. Color evaluation was performed using an Easyshade spectrophotometer at baseline (FOA, FOA + BLE, BLE), one month after (FOA + BLE) and 21 days after appliance removing (FOA + BLE and FOA groups), in each tooth bleached. The ANOVA and Tukey’s tests, with a significance level of 5%, were used for statistical analysis.ResultsThe GCF volume in the FOA + BLE and FOA groups significantly increased at the time points evaluated (p < 0.001); however, this did not occur in the BLE group (p > 0.05). On the other hand, NO- levels significantly decreased during dental bleaching with or without fixed orthodontic appliances (FOA + BLE and BLE groups; p < 0.05), while no significant changes were observed in the FOA group (p > 0.05). Significant changes in color were observed in the FOA + BLE and BLE groups compared to in the FOA group (p < 0.01). However, the presence of fixed orthodontic appliance (FOA + BLE) negatively affected the bleaching efficacy compared to BLE group (p < 0.01).ConclusionsDental bleaching did not increase the inflammatory parameters in patients wearing fixed orthodontic appliance. However, in the presence of orthodontic appliances, the bleaching efficacy was lower than that of bleaching teeth without orthodontic appliances.Trial registrationRBR-3sqsh8 (first trial registration: 09/07/2018).

Melasma: A Homoeopathic Approach

Melasma is an acquired pigmentary disorder. Its Pathogenesis is complex and involves the interplay of various factors, such as genetic predisposition, UV radiations, hormonal factors &amp; drugs. It is characterized by symmetrical hyperpigmented macules on face. Tropical bleaching agents, chemical peels have been shown to provide only minimal improvement in condition. It can generally affect a patient’s quality of life by causing embarrassment, fear of negative appraisal, frustration by discoloration. There are numerous effective homoeopathic treatments for melasma, but the choice is specific to the patient and takes into account both the patient's physical and mental symptoms. Homoeopathy has an individualistic and holistic approach prescription according to a different type of clinical presentation of cases. Keywords: Hyperpigmentation, Melasma, Pigmentary disorders, Chloasma, Homoeopathy.