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Abstract The majority of environmental researchers are becoming increasingly concerned with the manufacture of inexpensive adsorbents for the detoxification of industrial effluents. To address one of the significant and well-known pollution issues with certain drains that act as hotspots and contribute to coastal pollution in Alexandria, this study aims to develop an economical, ecologically friendly sorbent. This study assessed the efficacy of a biomass-coated magnetic composite and a magnetic active adsorbent for the removal of two dyes from an industrially contaminated sewer using a wetland plant (Phragmites australis). Using magnetic biosorbent, the biosorption of Xylenol orange and Congo red ions from polluted drain discharge in Abu Qir Bay was evaluated in the current study. Using scanning electron microscopy imaging and Fourier transform infra-red analysis; the surface function and morphology of the nano-biosorbent were examined. At room temperature, the effects of initial dye concentration, pH, contact time, and nano-biosorbent concentration have all been investigated. The greatest percentages that nano-biosorbent can remove from Congo red and Xylenol orange are 97% and 47%, respectively. The removal of the initial Congo red concentration varied from 42 to 97%, while the removal of the initial Xylenol orange concentration varied from 30 to 47%. The adsorption capacity was shown to be strongly pH-dependent; capacity dose as pH value increased, with pH 10 being the ideal pH for Congo red and pH 6 being the ideal pH value for Xylenol orange. The adsorption capacity for Congo red varied between 0.96 and 3.36 and the adsorption capacity for Xylenol orange varied between 0.18 and 17.58. The removal capacity decreased from 3.36 to 0.96 mg/g when the biosorbent dosage was increased from 0.05 to 0.5 g/L for Congo red, in case of Xylenol orange, the removal capacity increased from 0.18 to 17.58 mg/g when the biosorbent dosage was increased from 0.05 to 0.5 g/L. The removal capacity of Congo red increases quickly with time and varied from 1.66 to 1.88 of contact time; while the removal capacity of Xylenol orange varied between 3.08 and 4.62 of contact time. For the dyes under study, kinetics and adsorption equilibrium were examined. Within 180 min, the equilibrium was attained because to the quick adsorption process. For Congo red and Xylenol orange, the highest adsorption capacities were 3.36 and 17.58 mg g−1, respectively. The equilibrium data were assessed using a number of isotherm models, including Langmuir, Freundlich, BET, and Tempkin, while the kinetic data were examined using a variety of kinetic models, including pseudo-first- and pseudo-second-order equations. The pseudo-second-order equation provides the greatest accuracy for the kinetic data and Langmuir model is the closest fit for the equilibrium data.

The majority of environmental researchers are becoming increasingly concerned with the manufacture of inexpensive adsorbents for the detoxification of industrial effluents. To address one of the significant and well-known pollution issues with certain drains that act as hotspots and contribute to coastal pollution in Alexandria, this study aims to develop an economical, ecologically friendly sorbent. This study assessed the efficacy of a biomass-coated magnetic composite and a magnetic active adsorbent for the removal of two dyes from an industrially contaminated sewer using a wetland plant (Phragmites australis). Using magnetic biosorbent, the biosorption of Xylenol orange and Congo red ions from polluted drain discharge in Abu Qir Bay was evaluated in the current study. Using scanning electron microscopy imaging and Fourier transform infra-red analysis; the surface function and morphology of the nano-biosorbent were examined. At room temperature, the effects of initial dye concentration, pH, contact time, and nano-biosorbent concentration have all been investigated. The greatest percentages that nano-biosorbent can remove from Congo red and Xylenol orange are 97% and 47%, respectively. The removal of the initial Congo red concentration varied from 42 to 97%, while the removal of the initial Xylenol orange concentration varied from 30 to 47%. The adsorption capacity was shown to be strongly pH-dependent; capacity dose as pH value increased, with pH 10 being the ideal pH for Congo red and pH 6 being the ideal pH value for Xylenol orange. The adsorption capacity for Congo red varied between 0.96 and 3.36 and the adsorption capacity for Xylenol orange varied between 0.18 and 17.58. The removal capacity decreased from 3.36 to 0.96 mg/g when the biosorbent dosage was increased from 0.05 to 0.5 g/L for Congo red, in case of Xylenol orange, the removal capacity increased from 0.18 to 17.58 mg/g when the biosorbent dosage was increased from 0.05 to 0.5 g/L. The removal capacity of Congo red increases quickly with time and varied from 1.66 to 1.88 of contact time; while the removal capacity of Xylenol orange varied between 3.08 and 4.62 of contact time. For the dyes under study, kinetics and adsorption equilibrium were examined. Within 180 min, the equilibrium was attained because to the quick adsorption process. For Congo red and Xylenol orange, the highest adsorption capacities were 3.36 and 17.58 mg g−1, respectively. The equilibrium data were assessed using a number of isotherm models, including Langmuir, Freundlich, BET, and Tempkin, while the kinetic data were examined using a variety of kinetic models, including pseudo-first- and pseudo-second-order equations. The pseudo-second-order equation provides the greatest accuracy for the kinetic data and Langmuir model is the closest fit for the equilibrium data. [ABSTRACT FROM AUTHOR]

A nontoxic method that results in distinct and persistent marks in Haliotis midae juveniles is fundamental for field-based studies, abalone ranching, and stock enhancement programs. Developed (6 days after fertilization) H. midae larvae were batch-tagged with 25 and 50 mg L−1 of calcein and xylenol orange for 24 and 48 h to determine the effect on survival, settlement, and the persistence of the mark on the shell. Epifluorescence was detected in the shell spire of larvae tagged with either 25 mg L−1 or 50 mg L−1 of calcein for 24 and 48 h immediately after the staining (t0) and was visible after 51 days when the experiment was terminated. Survival of calcein stained larvae was higher after 24 h compared to 48 h immersion. However, percentage settlement was higher in the 48 h treatments when compared to 24 h treatments for both concentrations and dyes. Therefore, bright and persistent epifluorescence marks can be induced in H. midae shells using calcein (25 mg L−1 for 24 h) without negatively affecting the survival and settlement of larvae, post-immersion. [ABSTRACT FROM AUTHOR]

Aluminium is preferred over iron for various uses as it is lighter, rust-proof and has an exceptional strength-to-weight ratio. Aluminium is more reactive than iron because of its higher standard reduction potential but it forms a self-protective layer of Al2O3 due to its higher reducing potential. Still, aluminium is corroded in acidic and alkaline media. The present research paper reports the corrosion behaviour of aluminium in 0.1 M NaOH solution with Alizarin Red S (ARS) or Xylenol Orange (XO) as an inhibitor. Corrosion potential, Corrosion current, Tafel slopes (βc) and (βa) for aluminium corrosion have been potentiodynamically investigated. The weight loss method has also been used to calculate the inhibition efficiencies of these additives. The corroded surfaces have been characterized by SEM images. It is found that corrosion potential values change significantly towards the anodic direction in the presence of ARS but they are sifted towards a cathodic direction at a high concentration of XO. While ARS shows a corrosion inhibition effect, XO shows a reverse effect. The inhibition efficiency values of ARS and XO calculated from corrosion current in potentiodynamic polarization studies tally with those calculated from weight loss studies. Studies on a laboratory model of aluminium-air batteries in 0.1 M NaOH containing these organic additives show that the discharge curve of the cell is improved in the presence of ARS and XO in combination. The results are explained in terms of the formation of well-known Al+3.3ARS− and Al+3-XO6− complexes. At room temperature, 1.0 × 10−3 M solution of ARS is found effective in inhibiting the corrosion of aluminium while the same concentration of XO is acting as a corrosion accelerator. This interesting study can be very vital in the field of corrosion science.

Hydrogen peroxide is an important intra- and inter-cellular messenger. It has been reported that beverages such as tea and coffee generate H2O2. The aim of this study was to examine whether H2O2 is formed in infusions of medicinal herbs and to explain the mechanism of its formation. Infusions of sixteen herbs were studied and the presence of H2O2 was found in all cases. The highest concentrations of H2O2, exceeding 50 µM, were found in the infusions of leaves of Betula and Polygonum, as well as of the inflorescence of Tilia. Considerable amounts of diverse phenolic compounds were detected in the infusions. Two successive one-electron oxidations of phenolics are the main source of H2O2 in these infusions; as expected, the generation of semiquinone and superoxide radicals was confirmed. The infusions of medicinal herbs were also able to scavenge H2O2. The herbal infusions were cytotoxic to human ovary cancer SKOV-3 and PEO1 cells; this cytotoxicity was compromised by catalase added to the growth medium, demonstrating the contribution of H2O2 to the cytotoxic action of herbal extracts. [ABSTRACT FROM AUTHOR]

In this study chitosan (CS) was modified by coating with xylenol orange (XO). The batch adsorption of Pb(II) ions on modified chitosan (CS/XO) was investigated. The modification of chitosan was confirmed by FT-IR spectroscopy, scanning electron microscopy (SEM) and x-ray diffraction (XRD). The adsorption behaviour of the modified chitosan against Pb(II) ions were evaluated. Among these, pH effect, adsorbent dosage and initial concentration of Pb(II) ions. The results showed that the modified chitosan possesses good capacity for lead ions. The modified surface exhibited an affinity to chelating lead ions in solution, forming complex. The experimental results were examined by the Langmuir and Freundlich isotherm models. The maximum adsorption capacities of Pb(II) ions based on the Langmuir isotherm model were 0.457 mg/g. [ABSTRACT FROM AUTHOR]

In this work, a novel sensitive composition of Fricke radio-chromic gel dosimeter based on polyvinyl alcohol (PVA), xylenol orange (XO), and physical cross-linking agent gellan gum (GG) is presented and evaluated with two optically detection methods. The Fricke dosimeter was irradiated up to 30Gy using medical linear accelerator and analyzed optically using ultraviolet visible (UV–Vis) spectrophotometry technique at wavelengths of 585 nm (i.e., within the visible range) and two-dimensional optical imaging system of charge-coupled-device (CCD) camera with a uniform red light-emitting-diode (LED) array source. The Fricke dosimeter demonstrated important properties including independence of beam energy and dose rate over the range studied. In addition, these dosimeters have high sensitivity in the range of 0–10Gy, and significant low diffusion coefficient of 0.070 mm2 h−1. In addition, the composition shows a lower diffusion coefficient with respect to those reported so far for a Fricke dosimeter. The total uncertainty of the estimated doses for the Fricke dosimeter was 3.96% at 95% confidence level. • Fricke XO-PVA dosimeter with physical gellan gum cross-linker was studied with two optical read-out techniques. • The dosimeter sensitivity was higher than other Fricke XO-PVA and gelatin-based gel dosimeters reported previously. • The dosimeter shows a lower diffusion coefficient with respect to those reported so far for a Fricke dosimeter. • The total uncertainty of the estimated doses for the Fricke dosimeters was found to be and 3.96% at 95% confidence level. [ABSTRACT FROM AUTHOR]

a simple, acurate and rapid spectrophotometric method for determination of sulphite and thiamine hydrochloride (B1) is described. This method used proton transfer reaction between sulphite ion with xylenol orange at pH(7.6) to develop red colour adduct that of maximum absorption at 580 nm. This adduct was used for determination of thiamine hydrochloride by bleaching the red colour product (xylenol orange-sulphite) at the optimum conditions established for the determination of sulphite. Beer’s law is obeyed in the concentration range (10-1000) μg/25ml (i.e. 0.4-40) of sulphite and 10-2000, μg/25ml (i.e. 0.4-80) for thiamine hydrochloride at the selected wavelength, the molar absorbtivity 2.8×104 l.mol-1.cm-1 for SO32- and 2.69×104 l.mol-1.cm-1 for thiamine hydrochloride, Sandell's index for sensitivity 0.002857 μg .cm-2 for sulphite and 0.012537 μg .cm-2 for B1. Good recoveries of sulphite and thiamine hydrochloride from water samples and pharmaceutical formations are achieved using the proposed method.

In the estimation of Zr using the ultraviolet–visible (UV–Vis) spectrophotometric technique, fluoride interference is a decade-old unsolved problem. The process of repeated fuming with strong acids is often used to remove fluoride from the solution in order to estimate Zr using spectrophotometry analysis. For the first time, in this work, a simple use of AlCl3 is reported as a suppressing reagent to eliminate the interference of fluoride in the estimation of Zr. Xylenol orange in HCl medium is used as a complexing reagent. Linearity in the datum acquired from absorbance at 551 nm (λmax) is achieved over the concentration range 0.25–4.5 µg mL–1 of Zr with a molar absorptivity of 35030 L·mol–1·cm–1 and Sandell's sensitivity of 0.003 µg·cm–2. Zr is quantified in the variety of U–Zr alloys and various water samples using spectrophotometric detection with a classical univariate calibration with suppressing of fluoride interference through AlCl3. Results from this novel analytical method herein developed for the first time are compared with those achieved from gravimetric analysis. Graphical Abstract [ABSTRACT FROM AUTHOR]

• CTAB capped Ag0, Re0, and Ag@Re as persulfate heterogeneous activators. • Ag@Re exhibits excellent activation activity to generate reactive radical species. • Activation energy was found to be lower (32.6 kJ/mol) to the degradation of xylenol orange. • SO 4 -• is the major radical reactive species. Silver-rhenium bi-metallic nanoparticles (Ag-Re) were prepared by the combination of colloidal sols of silver and rhenium at room temperature. The silver and rhenium sols were synthesized by using the chemical reduction of silver nitrate and ammonium perrhenate with sodium borohydride in presence of cetyltrimethylammonium bromide (CTAB). The morphology (shape, size, elemental composition, oxidation states, and crystalline nature) and textural properties (pore size, pore volume, and surface area) of Ag0-Re0 were determined with EDX, SEM, TEM, XPS, XRD, and nitrogen adsorption-desorption isotherm. The Ag0-Re0 was used as heterogeneous persulfate (S 2 O 8 2−) activator to generate reactive radical species (SO 4 −• and HO•) for the degradation of xylenol orange (XO) at 434 nm. The Ag-Re exhibits higher XO degradation efficiency than that of mono-metallic Ag0 and Re0 nanoparticles, respectively. The degradation efficiency strongly depends on the concentrations of S 2 O 8 2−, XO, pH, temperature, and amount of Ag0-Re0. The role of SO 4 −• and HO• were established by using ethanol, and tertiary butanol as radical scavengers. The activation energy was found to be 85.2, 63.5, and 32.6 kJ/mol, respectively, to the degradation of XO by activated S 2 O 8 2− with Re0, Ag0, and Ag0-Re0. [Display omitted] [ABSTRACT FROM AUTHOR]

A spectrophotometric method, circumventing interference from F− ions, during estimation of Zr in U-Zr alloy fuel, has been developed. F− ions from added HF, for quantitative dissolution of metallic fuels, were converted to a strong ionic liquid complex using a cocktail of masking agents. Zr(IV) complexed with Xylenol Orange, displayed enhanced sensitivity below 1 μg/mL, in acetate buffer medium with masking agents, when F−was ≥ 5 μg/mL. Validation and standardization of the method has been accomplished, using arc melted and injection casted samples of U-Zr alloys, respectively. Prevention of interference from F− by masking agents was elucidated using density functional theory. [ABSTRACT FROM AUTHOR]

• A hybrid method of PCR-LAMP was developed for the detection of human Plasmodium species. • Able to detect five human Plasmodium species simultaneously. • Result is obtained by direct observation of end products by naked eyes. Combining the advantages of PCR and LAMP, we described a new technique, namely PCR-LAMP, for malaria diagnosis. The whole process of DNA amplification can be completed in 35 min. This hybrid amplification technique markedly improved the sensitivity of detection compared to the classic single PCR or LAMP assay alone. PCR-LAMP assay had a detection limit of 1 copy/µL for P. knowlesi and P. ovale , 0.1 copy/µL for P. vivax, P. falciparum and P. malariae , respectively. To facilitate the endpoint detection, xylenol orange was added. Positive samples were indicated in orange while negative reactions were violet. The inclusion of xylenol orange into the LAMP reaction mix significantly reduces the post-amplification workload. Without relying on the use of specific instruments, the color changes of the amplicons could be visualized directly through the naked eye. In conclusion, PCR-LAMP poses the potential to be developed as a new malaria molecular diagnosis tool. [ABSTRACT FROM AUTHOR]

Photooxidized psoralen solutions possess a variety of biological effects, which implementation mechanism may presumably involve hydroperoxides. Here, the hydroperoxide content in photooxidized psoralen solutions was assessed using photometric FOX assay (from Ferrous Oxidation + Xylenol Orange). FOX reagent with 10× content of Xylenol Orange, modified for quantitative analysis of up to 50 μM of hydroperoxides in aqueous phase was used in experiments. During photooxidation of 0.1 mM psoralen in phosphate buffer solution, hydroperoxide production increases with dose of UVA irradiation (~2.5 μM eq. of H2O2 for dose of 252 kJ/m2 and ~11 μM eq. of H2O2 for dose of 1512 kJ/m2) and reaches ~16.5 μM eq. of H2O2 at the highest dose investigated (3024 kJ/m2). A comparison of kinetics of psoralen photolysis and hydroperoxide generation allows us to suggest that generation of hydroperoxide results from the secondary photochemical processes involving psoralen photoproducts, presumably from photoinduced autooxidation of aldehydic photoproducts of psoralen.

A simple, low cost and fast method for the removal of xylenol orange from wastewater using poly urethane foam. The maximum removal was obtained by studying different parameter such as pH, contact time, adsorbent dose, and drug capacity. The optimum conditions for the removal of xylenol orange at pH=10 by using 0.1 g of PUF with contact time 60 min and 250 rpm The experimental isotherm data was studied using Langmuir and Freundlich isotherms. The results indicate that Langmuir isotherm can describe the adsorption process with adsorption capacity (qm) equal to 0.904 mg/g and with correlation coefficient (R²) equal to 0.972. [ABSTRACT FROM AUTHOR]

Cyclotron-produced radiometals must be separated from the irradiated target and purified from other metal impurities, which could interfere with the radiolabeling process. We compared different chromatographic and colorimetric methods to determine the amount of transition metals in radioactive samples. Besides commercially available colorimetric tests, 4-(2-pyridylazo)resorcinol and xylenol orange were used as a non-selective metal reagents, forming water-soluble chelates with most of the transition metals immediately. We compared the applicability of pre- and post-column derivatization, as well as colorimetric determination without separation. The studied chromatographic and colorimetric analyses are not suitable to completely replace atomic spectroscopic techniques for the determination of metal contaminants in radioactive samples, but they may play an important role in the development of methods for the purification of radiometals and in their routine quality control.

The molecularly imprinted polymers (MIPs) were prepared by using the non-covalent approach. In the polymerization process, xylenol orange was used as a template (T), acrylic acid as a functional monomer (M), divinylbenzene as a cross-linker (CL) and 2,2’-azobisisobutyronitrile (AIBN) as an initiator and microemulsion as a solvent. The synthesized polymers were characterized by using FTIR and SEM micrograph. The batch binding analysis was used to evaluate the rebinding efficiency of imprinted polymers. The highest rebinding efficiency was obtained from the MIP-R2 (0.1:0.6:2, T:M:CL). The selected MIP-R2 was used for the removal of xylenol orange from the water sample and have shown removal efficiency of about 80%. [ABSTRACT FROM AUTHOR]

The main aim of the current work is to investigate possible pharmacokinetic interactions between vardenafil hydrochloride (VAR), which is used for the treatment of erectile dysfunction and daclatasvir dihydrochloride (DAC), which is used for the treatment of chronic hepatitis C viral infection when they are concomitantly administered. Therefore, a sensitive and selective square‐wave voltammetric method was developed and validated for simultaneous determination of VAR and DAC using disposable pencil graphite electrode (PGE) modified with xylenol orange (X.O.) flakes as an electrochemical sensor. A full investigation of the experimental parameters for obtaining the highest electroanalytical signal with sufficient resolution between the oxidation peaks of two compounds was performed. It was found that VAR and DAC were resolved on X.O./PGE with different potentials at 1.4 V and 0.9 V, respectively using Britton‐Robinson buffer (pH 2.2) and 0.1 mol L−1 KCl as a supporting electrolyte. In addition, with the aid of cyclic voltammetry, a mechanistic scheme for the oxidation behaviour of both VAR and DAC was suggested. The proposed square wave voltammetric method was successfully applied for trace quantification of VAR and DAC in male rabbits. The suggested approach shows detection and quantification limits in rabbit plasma samples of 0.06 and 0.17 μmol L−1, respectively for VAR and 0.13 and 0.39 μmol L−1, respectively for DAC. The pharmacokinetic parameters of VAR alone and in combination with DAC after oral administration to rabbits were successfully estimated. The obtained results confirm that when DAC is co‐administered with VAR, plasma concentration of VAR increases, which necessitates dose adjustment for VAR to prevent toxicological consequences in patients. [ABSTRACT FROM AUTHOR]

In the present study, monodispersed silica nanoparticles (SNPs) were synthesized by sol–gel method. To enhance the properties like surface roughness, surface area, and percentage swelling, the SNPs were incorporated into the hydrogel Gelatin and Psyllium to synthesize a nanocomposite material. The percentage of swelling was optimized by varying different reactions parameters like temperature, pH, backbone ratio, monomer concentration, cross-linker concentration, initiator concentration and amount of solvent. On incorporation of SNPs, the great enhancement in various properties likes surface roughness, and percentage swelling (1656% from 1100%) was observed. As an adsorbent, the synthesized nanocomposite was investigated with a tremendous hike in the dye removal efficiency on the incorporation of SNPs into the hydrogel network. The synthesized nanocomposite was found to remove 2.385 mg g−1 of Brilliant green (BG) in 5 h whereas 1.56 mg g−1 removal of Xylenol orange (XO) within 4 h. The higher values of K2 and closeness of theoretical and experimental adsorption capacity values at all the concentrations in both the dyes confirmed the adsorption kinetics data fitted well with pseudo-second order rate model. The correlation values (0.966 for BG and 0.995 for XO) and favourable RL (0.345 for BG and 0.263 for XO) of the adsorption data suggested better fit for Langmuir adsorption for both the dyes. Further, the negative values of ΔGo and ΔHo confirmed the adsorption of BG and XO dyes on the adsorbent is a feasible reaction. The reusability affinity of the synthesized SNP based nanocomposite up to 4 cycles outshine as a superior adsorbent material for the removal of cationic and anionic dyes from waste water. [ABSTRACT FROM AUTHOR]

The BaseScope™ assay is a novel, highly sensitive RNA in situ hybridization (ISH) technique, allowing detection of short RNA sequences as well as discrimination between single-nucleotide alterations. Multiplexing BaseScope™ ISH with immunofluorescence assay has proven challenging because the diffusion of colorimetric dyes such as Fast Red in aqueous solutions degrades spatial resolution. In this study, we explore alkaline phosphatase-based fluorescent signal detection methods and integrate it with BaseScope™ RNA ISH. We found that Fast Blue BB/NAMP can be used in BaseScope™ ISH for signal detection. Additionally, we found that the calcium binding fluorochromes calcein and xylenol orange can be used to localize alkaline phosphatase activity in both immunohistochemistry (IHC) and BaseScope™ ISH assays. When applied to mouse brain and intestine tissue sections, we successfully detected circular RNA molecules and cell proliferation antigen Ki-67 proteins. This technological advance expanded the substrate selection of alkaline phosphatase-based BaseScope™ RNA ISH to allow researchers and clinical professionals accurately assess RNA targets with immunofluorescent multiplexing. [ABSTRACT FROM AUTHOR]

Analytical measurement of materials requires exact knowledge of their acid dissociation constant (pKa) values. In recent years, quantum mechanical calculations have been extensively used to study of acidities in the aqueous solutions and the results were compared with the experimental values. In this study, a theoretical study was carried out on xylenol orange (in water solution) by ab initio method. We calculated the pKa values of xylenol orange in water, using high-level ab initio (PM3), DFT (HF, B3LYP/6-31+G(d)) and SCRF methods. The experimental determination of these values (pKa,s) is a challenge because xylenol orange has a low solubility in water. We considered several ionization reactions and equilibriums in water that constitute the indispensable theoretical basis to calculate the pKa values of xylenol orange. The results show that the calculated pKa values have a comparable agreement with the experimentally determined pKa values. Therefore, this method can be used to predict such properties for indicators, drugs and other important molecules.

Reactive oxygen species (ROS) accumulation is one of the earliest hallmarks upon successful pathogen recognition in plants. H 2 O 2 is considered the most important ROS in plant defense considering its relatively high stability and capacity to cross long distances in the plant. However, ROS also play roles in cell development and could hence facilitate nematode feeding site development. Several methods to analyze the cellular redox state exist, among which ROS detection and quantification and the evaluation of ROS scavenging enzyme activity (peroxidase activity, catalase activity, etc.). Here, we describe DAB staining, which is used to detect and localize ROS in planta upon an external trigger. Furthermore, ROS quantification using the FOX assay is described. Both methods have been used extensively in research and yield repeatable results in various plants., (© 2024. The Author(s), under exclusive license to Springer Science+Business Media, LLC, part of Springer Nature.)

Background. Metals are necessary for plants to perform vital functions and their inclusion in polymers intended for crop production seems promising. The study of polymer-metal complexes (MPC) is of undoubted interest from the point of view of creating new biologically active polymers. Knowledge of the laws and features of the interaction of metals with macromolecular compounds will allow a deeper understanding of the mechanism of action of these compounds. The determination of metal ions in the composition of polymer metal complexes was previously carried out by elemental analysis. Purpose: to determine cobalt ions in the presence of xylene orange in cobalt-containing copolymers based on vinylcaprolactam and vinylpyrrolidone with crotonaldehyde. Methodology. The content of cobalt ions in the metal complex was determined on a device of the brand "KFK". Potentiometric titration was carried out on a potentiometer "Universal ionomer EV-74." Spectra in the visible region (200-750 nm) of copolymer solutions and complex compounds were recorded on an SF-26 spectrophotometer. Originality. A new method has been developed for determining cobalt and applying it to the analysis of copolymers based on vinylcaprolactam with crotonic aldehyde and vinylpyrrolidone with crotonic aldehyde containing from 1.19 to 12.57% cobalt. Findings. The effect of macroligands of vinylcaprolactam with crotonic aldehyde and vinylpyrrolidone with crotonic aldehyde on the determination of cobalt ions in the presence of xylenol orange was studied. It was shown that with a 1000-fold excess (in moles), the high molecular weight base of the copolymers of vinylcaprolactam with crotonic aldehyde and vinylpyrrolidone with crotonic aldehyde does not interfere. [ABSTRACT FROM AUTHOR]

Scale drop disease virus (SDDV) is an emerging pathogen that causes multiple outbreaks in farmed Asian sea bass across many regions in Southeast Asia and results in severe economic losses to the exports of fish. With no current standard vaccination protocol against this virus, routine testing that probes for SDDV in Asian sea bass culture can help farmers prevent a large-scale epidemic from occurring. Fish samples can be sent to accredited laboratories for SDDV test that is performed via polymerase chain reaction (PCR) and related methods, such as qPCR. Albeit its high sensitivity, PCR requires skilled labors and equipment only available in centralized laboratory settings, and therefore, not appropriate for the timely determination of SDDV. Herein, we report the development of a colorimetric assay based on loop-mediated isothermal amplification (LAMP) with a pH-sensitive xylenol orange (XO) reporter. With a rapid total DNA extraction method developed in this research, we were able to demonstrate that the sensitivity of the naked-eye detection was 100 picograms of total DNA extracted from the SDDV-infected Asian sea bass samples. In addition to its affordability, our LAMP-XO circumvents the technical challenges faced by PCR and allows the SDDV detection to be conveniently performed and analyzed at the potential site of an outbreak. • A colorimetric LAMP assay with pH-sensitive xylenol orange (XO) reporter was developed to detect SDDV in Asian sea bass. • The limit of naked-eye detection of LAMP-XO was 100 pg of total DNA extracted from the SDDV-infected Asian sea bass samples. • The technique was validated by field SDDV-infected and healthy Asian sea bass samples. • The technique is compatible with a rapid DNA extraction protocol using G3T buffer. • The LAMP-XO assay has a potential use in an active surveillance of L. calcarifer. [ABSTRACT FROM AUTHOR]

Tris(glycinato)Mn(III) and its mixed ligand complexes with azido-, thiocyanato-, chloro- and bromo- groups have been synthesized and characterized by UV–Vis spectrophotometry, IR spectrophotometry, elemental analysis, magnetic susceptibility measurements, thermal analysis, Dart-mass spectrometry, EPR spectral studies, and X-ray powder diffraction studies. The molar extinction coefficient values of the complexes are in the range of spin allowed 5T2g → 5Eg transitions. The magnetic susceptibility measurements of all the complexes confirmed the presence of four unpaired electrons and high spin d4 systems. Room temperature EPR spectrum gives g isotropic value 2.002 indicative of octahedral geometry for the complex. PXRD studies suggest monoclinic system with space group P21/c with a = 9.1382(60) Å, b = 15.5340(11) Å, c = 10.2576(68) Å, and β = 110.598(15)°. The particle size of the complexes lies in the range 26.60–38.79 nm. The tris(glycinato)Mn(III) is an efficient heterogeneous catalyst for decolorization of Xylenol Orange and Methyl Red in the presence of H2O2. It also initiates polymerization of acrylonitrile. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • A colorimetric chemosensor for Ni2+ was developed by the mixture of XO and PDADMAC in aqueous solution. • It could selectively detect Ni2+ by color change from red to purple. • The detection limit for Ni2+ was evaluated to be 0.074 μM. Abstract The combination of xylenol orange (XO) and poly(diallyldimethylammonium chloride) (PDADMAC) has been utilized as a colorimetric sensor for selective recognition of Ni2+ in aqueous solution. Upon addition of Ni2+, the chemosensor exhibited the significant color change from red to purple with a bathochromic shift, whereas these change was not induced by other metal ions. XO alone did not recognize Ni2+ colorimetrically, indicating that PDADMAC was required for detecting Ni2+. This study can provide the facile method for the construction of new chemosensors by a simple mixture of an anionic water-soluble dye and cationic polyelectrolyte. [ABSTRACT FROM AUTHOR]

Abstract Loop-mediated isothermal amplification (LAMP) can amplify DNA specifically and sensitively. Under minimal buffering conditions, it produces hydrogen ions that lower the pH of the solution upon DNA amplification. This characteristic was applied to visually detect amplified DNA of Escherichia coli through the use of Xylenol Orange, a pH-dependent dye. Under the optimal conditions, 120 min at 63 °C, the Xylenol orange-dependent colorimetric LAMP revealed a detection limit as low as 1 CFU, namely 100,000 times more sensitive than typical multiplex PCR, and showed no cross-reactions with other foodborne pathogens. The colorimetric assay was successfully exploited to detect E. coli contaminations in milk samples, showing high reliability and the same high sensitivity with naked-eye readout. Together with robustness, simplicity, and visual detectability of amplification, this assay can serve as an alternative tool to PCR for detecting E. coli , which is suitable for both laboratory and on-field applications. Highlights • Xylenol orange-based LAMP was developed for naked-eye detection of Escherichia coli. • The method is rapid, specific, and sensitive for the detection of E. coli. • The method detects E. coli as low as 1 CFU/reaction. • The method is suitable for detecting E. coli in water and milk. • The method offers the opportunities for on-field detection of E. coli. [ABSTRACT FROM AUTHOR]

The success rate of extracorporeal shock wave therapy (ESWT) for fracture nonunions in human medicine (i.e. radiographic union at 6 months after ESWT) is only approximately 75%. Detailed knowledge regarding the underlying mechanisms that induce bio-calcification after ESWT is limited. We analyzed the biological response within mineralized tissue of a new invertebrate model organism, the zebra mussel Dreissena polymorpha, after exposure with extracorporeal shock waves (ESWs). Mussels were exposed to ESWs with positive energy density of 0.4 mJ/mm2 (A) or were sham exposed (B). Detection of newly calcified tissue was performed by exposing the mussels to fluorescent markers. Two weeks later, the A-mussels showed a higher mean fluorescence signal intensity within the shell zone than the B-mussels (P

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Abstract: To enhance the adsorption performance, chitosan microspheres (CS–MSs) were grafted with polyethylenimine (PEI), a cationic compound with abundant amine groups. The resulting PEI‐grafted CS–MSs (PEI–CS–MSs) were used for the adsorption of xylenol orange (XO), an anionic dye. The results show that PEI–CS–MSs were in regular spherical shape without porous structure. XO molecules were adsorbed onto the amine groups of PEI–CS–MSs through electrostatic interaction. The maximum adsorption capacity of XO onto PEI–CS–MSs was 816.33 mg/g at 303 K, being much higher than that onto CS–MSs. The adsorption process could be properly described by the pseudo‐second‐order kinetic and Langmuir models. The adsorption of XO was a spontaneous process with exothermic nature. In addition, the adsorption capacity only decreased by 0.52 % after seven cycles of adsorption‐desorption, indicating the excellent reusability of PEI–CS–MSs. [ABSTRACT FROM AUTHOR]

A novel methodology involving the use of Gd3+–Xylenol Orange (Gd–XO), a solution colorimetric probe, was used to determine the conditional relative rates of complex formation between the Gd3+ ion and polyamino carboxylate ligands used in MRI contrast agent development. Among the ligands tested, the order of rate of Gd‐complex formation was found to be DTPA ≈ DOTP > DOTA > DO3A > DOTAM. The observed rates are an effect of ligand denticity, backbone structure, and nature of the ligand donor groups. [ABSTRACT FROM AUTHOR]

Using the mathematical planning of the experiment by the method of Latin squares, we optimize the adsorption conditions for Bi(III) from dilute aqueous solutions and its desorption from the surface of silica gel L100/250. It is found that the maximum degree of adsorption (95-98%) is reached at pH 4.5, near the zero-charge point of silica gel and under the domination of the Bi(OH)3 monomeric hydroxyl species in solution. The adsorption time does not exceed 30 min with an adsorbent weight of 0.4 g, and the maximum desorption is observed when Bi(III) is eluted with a 0.5 M nitric acid solution for 20 min. An adsorption-spectroscopic procedure for the determination of Bi(III) with Xylenol Orange is developed. The calibration dependence is linear in the concentration range of 0.25 to 6.0 μg/mL, and the detection and determination limits are, respectively, 0.09 and 0.28 μg/mL. The procedure is tested using standard reference samples of tungsten ores and molybdenum concentrate; the relative standard deviation does not exceed 4%. [ABSTRACT FROM AUTHOR]

This study describes a new voltammetric method for sensitive and accurate determination of boron using the poly xylenol orange-modified and oxidized pencil graphite electrode. The oxidation of tiron at þ0.86 V in the boron-tiron complex formed in phosphate buffer solution at pH 8 was evaluated as a response. The parameters for voltammetric determination of boron were optimized. The modified electrode was characterized by cyclic voltammetry, electrochemical impedance spectroscopy, scanning electron microscopy, and energy-dispersive X-ray spectroscopy. The limits of detection and quantification were estimated to be 28 and 83 μg/L, respectively. The relative standard deviation value was 4.89% for 0.2 mg/L boron. The recovery results were 98.72, 100.53, and 100.14% for tap water, drinking water, and eye lotion samples, respectively. The accuracy of the method was tested using a certified reference material (UME CRM 1201: Elements in Spring Water). [ABSTRACT FROM AUTHOR]

Bacillus anthracis spores can make humans infected with vicious anthrax, so it is significant to detect their biomarker 2,6-pyridinedicarboxylic acid (DPA). The development of dual-modal methods for DPA detection that are more flexible in practical applications remains a challenge. Herein, colorimetric xylenol orange (XO) was modified on fluorescent CdTe quantum dots (QDs) for dual-modal detection of DPA through competitive coordination. After the binding of XO on CdTe QDs via coordination with Cd2+, CdTe QDs displayed quenched red fluorescence and the bound XO was presented as red color. The competitive coordination of DPA with Cd2+ made XO released from CdTe QDs, causing the enhanced red fluorescence of CdTe QDs and the yellow color of free XO. On this basis, DPA was rapidly (1 min) quantified through fluorescent and colorimetric modes within the ranges of 0.1–5 μM and 0.5–40 μM, respectively. The detection limits for DPA were calculated as low as 42 nM and 240 nM, respectively assigned to fluorescent and colorimetric modes. The level of urinary DPA was further measured. Satisfactory relative standard deviations (fluorescent mode: 0.1%–10.2%, colorimetric mode: 0.8%–1.8%) and spiked recoveries (fluorescent mode: 100.0%–115.0%, colorimetric mode: 86.0%–96.6%) were obtained. [Display omitted] • Colorimetric xylenol orange and fluorescent CdTe QDs were combined via coordination. • They served as the fluorescent/colorimetric dual-modal probe for anthrax biomarker. • The mechanism relied on competitive coordination of anthrax biomarker with CdTe QDs. [ABSTRACT FROM AUTHOR]

The removal ofxylenol orange from aqueous solution onto the coal ash was investigated at room temperature. The results show that the adsorption capacity of xylenol orange increased as the adsorption time increased and then equilibrium established after 30 min adsorption time. The results obtained revealed that the coal ash removed about 80 % of xylenol orange from the aqueous solution within 40 min. The effect of pH also studied, which showed that the adsorption of xylenol orange on the coal ash decreased as pH increased. The equilibrium adsorption isotherm data was fitted in Langmuir and Freundlich model equation and was found that the data followed both Langmuir and Freundlich isotherm models. Furthermore, we used a statistical measure (rank equation) in order to measure the strength of the relationship between the adsorption of xylenol orange onto coal ash and different adsorption time, and adsorption of different concentration of dye at equilibrium time.