Enhanced photocatalytic activity of methylene blue using heterojunction Ag@TiO_(2)nanocomposite:Mechanistic and optimization study

The objective in this study is to investigate the adsorption-degradation of the methylene blue(MB)dye using a fabricated heterojunction Ag@TiO_(2)nanocomposite.The batch factors used in photo catalytic reactions were pH,UV-irradiation time,temperature,catalytic dosage,and concentration of MB.The results showed that 0.2×10^(3) g·ml^(-1))of the catalytic dose caused the Ag@TiO_(2)adsorption to degrade by 96.67%with darks and UV exposure.Using the Langmuir-Hinshelwood model to determine the kinetic,the Ag@TiO_(2)displays a greater kinetic rate than TiO_(2)and silver nanoparticle(AgNPs).The photocatalytic degradation of MB,which is an endothermic reaction involving all catalysts,is shown by the thermodynamic parameter to have the positive value of enthalpy(ΔH°).The enthalpies observed were Ag@TiO_(2)(126.80 kJ·mol^(-1))<AgNPs(354.47 kJ·mol^(-1))<TiO_(2)(430.04 kJ·mol^(-1)).Ascorbic acid(·OH scavenger),2-propanol(·O_(2)scavenger),and ammonium oxalate(AO)(hole h+scavenger)were employed to conduct the scavenger effects.The Ag@TiO_(2)demonstrated a reduction in MB degradation when combined with 2-propanol,and this clearly demonstrated that,in contrast to hydroxyl radicals(·OH)and holeh scavengers,superoxide radical anion(O_(2)scavenger)plays a significant role in MB degradation.Utilizing density functional theory(DFT)to elucidate the mechanism and B3LYP/6-311+G(d,p)level optimization,the degradation-adsorption process was explained.When the N-N,C-N or C-C bonds were severed,the Fukui faction was demonstrated for nucleophilic,electrophilic,and radical attack.

A case study illustrating the use of an integrated approach to treat secondary Anal Fistula Post I&D of Perianal Abscess

Background:Anal fistula is a long-term disease characterized by a tubular structure with one end opening in the anorectal canal and the other end opening on the surface of the perineum or perianal skin with chronic pus drainage.It is linked to Bhagandar in Ayurveda,and in Sushruta Samhita,Acharya has mentioned 5 forms of Bhagandar.The boil in the present case was Shukla,sthira i.e.hard and firm,with Picchila strava and Kandu resembling the features of Parisraavi bhagandar.Aim and objective:The current case was diagnosed as Parisravi bhagandar,which resembles trans-sphincteric or intersphincteric fistula in modern ano.In Ayurveda,the management of Parisraavi Bhagandar,Shastra,kshara,and Agnikarma is advised and the use of Ksharasutra,which contributes to complete cutting and healing of the track without reoccurrence,similarly Modern surgeon depends on surgery i.e radical excision of the track,ligation with Seton,and use of chemical irritants like urethane,silver nitrates,etc.A cutting seton(tight)gently slices the confined muscle to close the fistula with the least interruption to continence.This operation is especially advised when a one-stage fistulotomy poses a considerable risk of incontinence.Material and methods:The method performed here was Core Partial Fistulectomy followed by Ksharasutra application till complete healing of the wound.Discussion and conclusion:This case study provides the successful management of Parisraavi Bhagandara(high anal,trans-sphincteric fistula in ano)in 61-year-old male patient with an integrated surgical&Ayurvedic management approach.

High surface area and mesoporous activated carbon from KOH-activated dragon fruit peels for methylene blue dye adsorption:Optimization and mechanism study

In this study,an alternative precursor for production of activated carbon was introduced using dragon fruit(Hylocereus costaricensis)peel(DFP).Moreover,KOH was used as a chemical activator in the thermal carbonization process to convert DFP into activated carbon(DFPAC).In order to accomplish this research,several approaches were employed to examine the elemental composition,surface properties,amorphous and crystalline nature,essential active group,and surface morphology of the DFPAC.The BrunauerEmmettTeller test demonstrated a mesoporous structure of the DFPAC has a high surface area of 756.3 m2g 1.The cationic dye Methylene Blue(MB)was used as a probe to assess the efficiency of DFPAC towards the removal of MB dye from aqueous solution.The effects of adsorption input factors(e.g.DFPAC dose(A:0.040.12 g L 1),pH(B:310),and temperature(C:3050℃))were investigated and optimized using statistical analysis(i.e.BoxBehnken design(BBD)).The adsorption kinetic model can be best categorized as the pseudofirst order(PFO).Whereas,the adsorption isotherm model can be best described by Langmuir model,with maximum adsorption capacity of DFPAC for MB dye was 195.2 mg g 1 at 50℃.The adsorption mechanism of MB by DFPAC surface was attributed to the electrostatic interaction,pp interaction,and Hbonding.Finally,the results support the ability of DFP to be a promising precursor for production of highly porous activated carbon suitable for removal of cationic dyes(e.g.MB).

Removal of the Methylene Blue Dye (MB) with Catalysts of Au-TiO₂: Kinetic and Degradation Pathway

Au-TiO2 catalysts were used in the photocatalytic degradation of the methylene blue dye (MB). The synthesis of titanium oxide (TiO2) was carried out by sol-gel method. Subsequently, particles of Au were deposited on the surface of the semiconductor by photo-deposition, thus modifying the surface of the semiconductor. For the characterization of the catalyst obtained, the techniques of X-ray Diffraction (DRX), Scanning Electron Microscopy (SEM), Spectroscopy with Diffuse Reflectance (DR) and Surface Area by the BET (Brunauer, Emmett y Teller) were used. The solid obtained was tested experimentally as a catalyst in the photocatalytic degradation of a solution of MB. The data obtained were analyzed by UV-vis Spectroscopy and Total Organic Carbon (TOC) and the results indicated conversions were greater than 80%. The intermediate products were evaluated by mass coupled gas chromatography (GC-MS) and the MB decomposition route was by hydroxylation, obtaining aromatic intermediates, esters and products of the chemical degradation of the molecule.

Kinetic analysis of experiment data for the formation of C.I.Acid Blue 9 leuco compound

A systematic study of the synthesis of C.I.Acid Blue 9 leuco compound in water is reported.The kinetic analysis of experimental data for the condensation reaction between 2-formylbenzenesulfonic acid sodium and N-ethyl-N-(3'-sulfonic acid benzyl) aniline obtained at four different temperatures ranging between 85 and 100°C is discussed.It is shown that the reaction followed second-order rate kinetics.The overall rate constant(k) increased with the increase of temperature.On the basis of the value of k,activation energy(E_a) of the reaction was evaluated.Importantly,it is found that reactant concentration has great effect on the formation of C.I.Acid Blue 9 leuco compound,implying that it is not enough to improve the conversion of N-ethyl-N-(3'-sulfonic acid benzyl) aniline by only prolonging reaction time in the late period of the reaction.

A Kinetic Spectrophotometric Method for the Determination of Iron (Ⅲ) in Water Samples

A new kinetic spectrophotometric method has been developed for the determination of iron （Ⅲ）. The method is based on the catalytic effect of iron （Ⅲ） on the oxidation of weak acid brilliant blue dye （RAWL） by KIO4 in acid medium. The advantages of the proposed method are that it is sensitive, accurate, rapid, inexpensive, can be operated under room temperature and has a large determination concentration range compared to other techniques. The obtained optimum conditions are： pH 3.15, RAWL （200 mgL^-1） 5.00mL, Potassium periodate solution （0.01 molL^-1） 0.30mL, phenanthroline （0.02 molL^-1） 1.00mL, reaction temperature 25℃ and reaction time 7 min. With this method iron could quantitively be determined in the range 0.00-0.02 mgL^-1, the detection limit being 4.10 × 10^10gmL^-1. The relative standard deviations （RSD） in five replicate determinations for 3 μgL^-1and 5 μgL^-1 iron （Ⅲ） are 3.1% and 1.9%, respectively. The method has been applied to the determination of iron （Ⅲ） in tap water samples and seawater samples （from the South China Sea）, the recovery rates being 98.0% and 100.5%, respectively.

Determination of Trace Copper (Ⅱ) in Water Samples by Kinetic-spectrophotometry

A new kinetic-spectrophotometric method is proposed for the determination of copper (Ⅱ). The method is based on the catalytic effect of copper (Ⅱ) on the oxidation of weak acid brilliant blue dye (RAWL) by hydrogen peroxide. The copper (Ⅱ) can be determined spectrophotometrically by measuring the decrease of absorbance of RAWL at λ = 626 nm using the fix-time method. The optimum reaction conditions are as follows: pH 7.20, buffer solution NaOH-KH2PO4, RAWL (200 mg L-1) 5.00 mL, H2O2 (30%) 0.50 mL, reaction temperature 80℃ and reaction time 20 min. The linear range of this method is between 0 μg L-1 and 12 μg L-1 and the limit of detection is 0.011 μg L-1, the relative standard deviation (RSD) in five replicate determinations for 2 and 8 μg L-1 copper (Ⅱ) are 3.2% and 2.3%, respectively. Twenty ions do not interfere in the determination of copper (Ⅱ). The method has been applied satisfactorily to the determination of copper (Ⅱ) in freshwater samples (tap water and Yellow River water from Lijin, Shandong, China) and seawater samples (from the South China Sea), the recovery rates are 98.0%, 102.5% and 96.0%, respectively.

Measurement of Trace Manganese(Ⅱ) by the Catalytic Kinetic Spectrophotometric Method

A new kinetic spectrophotometric method is developed for the measurement of manganese(Ⅱ) in water. The method is based on the catalytic effect of manganese(Ⅱ) with the oxidation of weak acid brilliant blue dye(RAWL) by KIO4 using the Nitrilo triacetic acid(NTA) as an activation reagent. The optimum conditions obtained are 40 mgL-1 RAWL,1×10-4molL-1 KIO4,2×10-4 molL-1 Nitrilo triacetic acid(NTA),pH = 5.8,the reaction time of 3.00 min and the temperature of 20.0 ℃. Under the optimum conditions,the proposed method allows the measurement of manganese(Ⅱ) in a range of 0-50.0 ng mL-1 and with a detection limit of down to 0.158 ng mL-1. The recovery efficiency in measuring the standard manganese(Ⅱ) solution is in a range of 98.5%-102%,and the RSD is in a range of 0.76%-1.25%. The new method has been successfully applied to the measurement of manganese(Ⅱ) in both fresh water and seawater samples with satisfying results. Moreover,few cations and anions interfere with the measurement of manganese(Ⅱ). Compared with other kinetic catalytic methods and instrumental methods,the proposed method shows fairly good selectivity and sensitivity,low cost,cheapness,low detection limit and rapidity. It can be applied on boats easily.

Progesterone is neuroprotective by inhibiting cerebral edema after ischemia

Ischemic edema can alter the structure and permeability of the blood-brain barrier. Recent studies have reported that progesterone reduces cerebral edema after cerebral ischemia. However, the underlying mechanism of this effect has not yet been elucidated. In the present study, progesterone effectively reduced Evans blue extravasation in the ischemic penumbra, but not in the ischemic core, 48 hours after cerebral ischemia in rats. Progesterone also inhibited the down-regulation of gene and protein levels of occludin and zonula occludens-1 in the penumbra. These results indicate that progesterone may effectively inhibit the down-regulation of tight junctions, thereby maintaining the integrity of the blood-brain barrier and reducing cerebral edema.

Study on the Determination of Trace Ni(II) by the Catalytic Kinetic Spectrophotometric Method

A new kinetic spectrophotometric method has been developed for the determination of trace Ni （Ⅱ in natural water. The method is based on the catalytic effect of Ni （Ⅱ） on the oxidation of weak acid brilliant blue dye （RAWL） by KIO4 in acid medium. The concentration of nickel （Ⅱ） can be determined spectrophotometrically by measuring the decrease of absorbance of RAWL at λ = 626 nm using the fix-time method. The influencing factors are investigated by the orthogonal experimental design. The obtained optimum analytical conditions are： pH = 2.00, CRAWL = 5.00×10^-5 mol·L^-1, c KlO4 = 2.00× 10^-5 mol·L^-1, the reaction time t= 10min and the temperature T = 25 ℃. Under the optimum conditions, the developed method allows the measurement of Ni （Ⅱ） in a range of 0 - 40.0ngmL1. The standard deviation of eleven independent measurements of blank reaction is S = 3.08× 10^-3 and the limit of detection is 2.20ng·mL^-1. The relative standard deviations （RSDs） in six replicate determinations of 5 ngmL-1 and 8 ngmL1 Ni （Ⅱ） are 2.87% and 1.11%, respectively. Moreover, the experiments show few cations and anions can interfere with the measurement of Ni （Ⅱ）. The recovery efficiencies of this method are in a range of 97.0%-102.5% in freshwater samples. But there is a decreasing effect, which is about 0.2 times the added Ni （Ⅱ） in seawater medium. After reasonable calibration this processing method is used for the determination of Ni （Ⅱ） in seawater samples successfully. The results show this developed method has high accuracy and precision, high sensitivity, large range of linearity and high speed. The method can, therefore, be employed at room temperature.

Targeted Blue Nanoparticles as Photoacoustic Contrast Agent for Brain Tumor Delineation

Distinguishing a tumor from non-neoplastic tissue is a challenging task during cancer surgery. Several attempts have been made to use visible or fluorescent agents to aid in the visualization of a tumor during surgery. We describe a novel method to delineate brain tumors, using a highly sensitive photoacoustic imaging technique that is enhanced by tumor-targeting blue nanoparticles serving as a contrast agent. Experiments on phantoms and on rat brains, ex vivo, demonstrate the high sensitivity of photoacoustic imaging in delineating tumors containing contrast agent at a concentration much lower than needed for visualization by the naked eye. The limit of detection of the system for the nanoparticles is about 0.77 μg/mL in water （equivalent to 0.84 μmol/L Coomassie Blue dye）. The present exploratory study suggests that photoacoustic imaging, when used with strongly optical absorbing contrast agents, could facilitate cancer surgery intraoperatively by revealing the distribution and extent of the tumor.

Retrospective analysis of sentinel lymph node biopsy using methylene blue dye for early breast cancer

Background:Methylene blue is the most commonly used tracer for sentinel lymph node(SLN)biopsy(SLNB)in China.This study aimed to investigate the feasibility of clinical application of SLNB using methylene blue dye(MBD)for early breast cancer and the prognosis of patients with different SLN and non-SLN statuses.Methods:We retrospectively analyzed the clinicopathological data of patients with early breast cancer treated at the Peking University First Hospital between 2013 and 2018.We calculated the SLN identification rate(IR)in SLNB with MBD and the false-negative rate(FNR),and analyzed the prognosis of patients with different SLN and non-SLN statuses using Kaplan-Meier curves.Results:Between January 2013 and December 2018,1603 patients with early breast cancer underwent SLNB with MBD.The SLN IR was 95.8%(1536/1603).Two SLNs(median)were detected per patient.There were significant differences in FNR between patients with SLN micrometastasis and macrometastasis(19.0%vs.4.5%,χ^(2)=12.771,P<0.001).Chi-square test showed that there were significant differences in SLN successful detection rates among patients with different vascular tumor embolism status(96.3%vs.90.8%,χ^(2)=9.013,P=0.003)and tumor(T)stages(96.6%vs.94.1%,χ^(2)=5.189,P=0.023).Multivariate analysis showed that vascular tumor embolism was the only independent factor for SLN successful detection(odds ratio:0.440,95%confidence interval:0.224-0.862,P=0.017).Survival analysis showed a significant difference in disease-free survival(DFS)between patients with non-SLN metastasis and patients without non-SLN metastasis(P=0.006).Conclusion:Our single-center data show that,as a commonly used tracer in SLNB in China,MBD has an acceptable SLN IR and a low FNR in frozen sections.This finding is consistent with reports of dual tracer-guided SLNB.Positive SLNs with non-SLN metastasis are associated with DFS.

Comparative assessment for removal of anionic dye from water by different waste-derived biochar vis a vis reusability of generated sludge

In this study,four biochars prepared from different crop residue waste i.e.sugarcane bagasse(SBB),coconut shell(CNB),paddy straw(PDB),and distilled waste of lemongrass(LGB)were evaluated for removal of Remazol Brilliant Blue R from the aqueous system.The RBBR adsorption capacities of biochar were 97-79%for SBB,99.9-99.47%for CNB,66.1-48%for PDB,and 78-68%for LGB,dominantly controlled by their aromaticity and mineral content.The Langmuir and Freundlich isotherms and pseudo-second-order kinetic models have described the chemisorption of RBBR on biochar surfaces.The thermodynamic data suggested that adsorption was spontaneous and endothermic.These biochars demonstrated excellent reusability(till four cycles with 50-61%regeneration).The purified water and biochar dye sludge demonstrated no phytotoxicity.The findings obtained in this study may provide supports for the potential of biochars for anionic dye removal from water and utilization of generated sludge for zero waste-producing technologies in the future.

Synthesis of malachite@clay nanocomposite for rapid scavenging of cationic and anionic dyes from synthetic wastewater

Synthesis of malachite@clay nanocomposite was successfully carried out for the removal of cationic（Methylene Blue,MB） and anionic dyes（Congo Red,CR） from synthetic wastewater.Nanocomposite was characterized by TEM,SEM,FT-IR,EDS analysis and zeta potential.TEM analysis indicated that the particle diameter of nanocomposite was in the range of 14 to23 nm.Various important parameters viz.contact time,concentration of dyes,nanocomposite dosage,temperature and solution pH were optimized to achieve maximum adsorption capacity.In the case of MB,removal decreased from 99.82%to 93.67%while for CR,removal decreased from 88.55%to 75.69%on increasing dye concentration from 100 to 450 mg/L.pH study confirmed the higher removal of CR in acidic range while MB removal was higher in alkaline range.Kinetic study revealed the applicability of pseudo-second-order model for the adsorption of both dyes.Negative values of AG0 for both systems suggested the feasibility of dye removal and support for spontaneous adsorption of CR and MB on nanocomposite.Nanocomposite showed 277.77 and 238.09 mg/g Langmuir adsorption capacity for MB and CR respectively.Desorption of dyes from the dye loaded nanocomposite was easily carried out with acetone.The results indicate that the prepared malachite@clay nanocomposite is an efficient adsorbent with high adsorption capacity for the aforementioned dyes.