A thiazole-based colorimetric and photoluminescent chemosensors for As3+ ions detection: Density functional theory, test strips, real samples, and bioimaging applications.

A Schiff-base Ethyl (E)-2-(3-((2-carbamothioylhydrazono)methyl)-4-hydroxyphenyl)-4-methylthiazole-5-carboxylate (TZTS) dual functional colorimetric and photoluminescent chemosensor which includes thiazole and thiosemicarbazide has been synthesized to detect arsenic (As3+) ions selectively in DMSO: H2O (7:3, v/v) solvent system. The molecular structure of the probe was characterized via FT-IR, 1H, and 13C NMR & HRMS analysis. Interestingly, the probe exhibits a remarkable and specific colorimetric and photoluminescence response to As3+ ions when exposed to various metal cations. The absorption spectral changes of TZTS were observed upon the addition of As3+ ions, with a naked eye detectable color change from colorless to yellow color. Additionally, the chemosensor (TZTS) exhibited a new absorption band at 412 nm and emission enhancements in photoluminescence at 528 nm after adding As3+ ions. The limit of detection (LOD) for As3+ ions was calculated to be 16.5 and 7.19 × 10-9 M by the UV-visible and photoluminescent titration methods, respectively. The underlying mechanism and experimental observations have been comprehensively elucidated through techniques such as Job's plot, Benesi-Hildebrand studies, and density functional theory (DFT) calculations. For practical application, the efficient determination of As3+ ions were accomplished using a spike and recovery approach applied to real water samples. In addition, the developed probe was successfully employed in test strip applications, allowing for the naked-eye detection of arsenic ions. Moreover, fluorescence imaging experiments of As3+ ions in the breast cancer cell line (MCF-7) demonstrated their practical applications in biological systems. Consequently, these findings highlight the significant potential of the TZTS sensor for detecting As3+ ions in environmental analysis systems.

Pyridine appended pyrimidine bis hydrazone: Zn2+/ATP detection, bioimaging and functional properties of its dinuclear Zn(II) complex.

A pyridine functionalized pyrimidine-based system, H2P was successfully synthesized, characterized, and evaluated for its remarkable selective characteristics towards Zn2+ and ATP ions. The chemical sensing capabilities of H2P were demonstrated through absorption, fluorescence, and NMR spectroscopic techniques. The probe exhibited outstanding sensitivity when interacting with the ions, demonstrating relatively strong association constants and impressively low detection limits. The comprehensive binding mechanism of H2P with respect to Zn2+ and ATP ions was investigated using a combination of analytical methods, including Job's plot, NMR spectroscopy, mass spectrometry, and density functional theory (DFT) experiments. The interesting sensing ability of H2P for Zn2+/ATP ions was harnessed for live cell bioimaging and other diverse on-site detection purposes, including paper strips, cotton swabs, and applications involving mung bean sprouts. Further, the fluorescent probe demonstrated its effectiveness in detecting Zn2+ and ATP within live cells, indicating its significant potential in the realm of biological imaging applications. Moreover, the molecular configuration of the zinc complex (H2P-Zn2Cl4), derived from H2P, was elucidated using X-ray crystallography. This complex exhibited intriguing multifunctional attributes, encompassing its capability for detecting picric acid and for reversible acid/base sensing responses. The enhanced conducting behavior of the complex as well as its resistance properties were investigated by performing I-V characteristics and electrochemical impedance spectroscopic (EIS) experiments respectively.

A computational and experimental study of cis-trans isomeric pesticides based on collision-induced dissociation of high-resolution mass spectrometry.

RATIONALE: Pesticide isomers are widely available in agricultural production and may vary widely in biological activity, potency, and toxicity. Chromatographic and mass spectrometric analysis of pesticide isomers is challenging due to structural similarities. METHODS: Based on liquid chromatography time-of-flight mass spectrometry, identification of cis-trans isomeric pesticides was achieved through retention time, characteristic fragment ions, and relative abundance ratio. Furthermore, theoretical and basic research has been conducted on the differences in characteristic fragment ions and their relative abundance ratios of cis-trans isomers. On the one hand, the cleavage pathways of six cis-trans isomers were elucidated through collision-induced dissociation to explain different fragment ions of the isomers. On the other hand, for those with the same fragment ions but different abundance ratios, energy-resolved mass spectrometry combined with computational chemical density functional theory in terms of kinetics, thermodynamics, and bond lengths was employed to explain the reasons for the differences in characteristic fragment ions and their abundance ratios. RESULTS: A high-resolution mass spectrometry method was developed for the separation and analysis of cis-trans isomers of pesticides in traditional Chinese medicine Radix Codonopsis, and six pesticide isomers were distinguished by retention time, product ions, and relative abundance ratios. The limits of quantification of the six pesticides were up to 10 µg/kg, and the linear ranges of them were 10-200 µg/kg, with coefficients of determination (R2) > 0.99, which demonstrated the good linearity of the six pesticides. The recoveries of the pesticides at spiked concentrations of 10, 20, and 100 µg/kg reached 70-120% with relative standard deviations ≤20%. CONCLUSIONS: It was demonstrated that the application of the method was well suited for accurate qualitative and quantitative analysis for isomers with different structures, which could avoid false-negative results caused by ignoring other isomers effectively.

Tradeoffs between pH, dissolved organic carbon, and mineral ions regulate cadmium uptake by Solanum hyperaccumulators in calcareous soil.

Soil solution pH and dissolved organic carbon (DOC) influence cadmium (Cd) uptake by hyperaccumulators but their tradeoff in calcareous soils is unclear. This study investigated the mechanisms of Solanum nigrum L. and Solanum alatum Moench in calcareous soil using a combination of concentration gradient experiments (0.6-100 mg Cd kg-1) and soil solution composition analysis. The results showed that the soil solution pH of S. nigrum remained stable despite Cd stress. On average, the soil solution pH of S. alatum was 0.23 units higher than that of S. nigrum, although pH decreased significantly under high Cd stress. In addition, the concentrations of potassium (K) and calcium (Ca) in the soil solution of S. nigrum increased and decreased under low and high levels of Cd stress, respectively. In S. alatum, the K and Ca concentrations in the soil solution generally increased with increasing Cd stress levels. Moreover, the level of DOC in the soil solution of both plants was higher under Cd stress compared to the control, and a gradually increasing trend with Cd stress level was observed in S. alatum. Consequently, the bioconcentration factors of the roots (2.62-19.35) and shoots (1.20-9.59) of both plants were >1, while the translocation factors were <1, showing an obstacle of Solanum hyperaccumulators in transferring Cd into their aboveground parts. Redundancy analysis revealed that the Cd concentration in S. nigrum roots was significantly negatively correlated with the soil solutions of K and Ca. In contrast, Cd concentrations in S. alatum roots and shoots were significantly positively correlated with soil solution DOC, K, and Ca but negatively correlated with pH. Our results suggest that calcareous soil neutralizes the acidity of released protons but does not affect cation exchange, inhibiting DOC in assisting the translocation of Cd within plants.

New materials-based on gelatin coordinated with zirconium or aluminum for ecological retanning.

Ecological retanning agent is an effective way to solve the pollution source of leather manufacturing industry. In this study, the gelatin from chrome-containing leather shavings in the leather industry was used to realize sustainable leather post-tanning. The gelatin hydrolysate (GH) coordinated with Zr4+ or Al3+ to prepare eco-friendly retanning agents GH-Zr and GH-Al. The successful coordination between GH and metal ions was characterized by FTIR and XPS. The retanning agents were characterized by FTIR curve-fitting and circular dichroism spectroscopy. The results showed that the conformation of the secondary structure of the polypeptide became ordered and stable after coordinating with the metal ions. The particle size and weight average molecular weight of the retanning agents were ~1700 nm and ~2100, respectively, measured by nanoparticle size analyzer and gel permeation chromatography (GPC). The retanning agents were applied to retanning of chrome tanned leather and glutaraldehyde tanned leather. The abundant free amino from retanning agents can consume the free formaldehyde. Meanwhile, retanning agents can effectively improve the multiple binding sites, resulting in favorable thickening rate (>110 %) and excellent dye and fatliquor absorption rate with ~99.91 % and ~93.18 %. Thus, this strategy can provide a viable choice for solid leather waste and sustainable development of the leather industry.

Effects of dietary rumen-protected choline supplementation to periparturient dairy cattle on inflammation and metabolism in mammary and liver tissue during an intramammary lipopolysaccharide challenge.

The objective of this experiment was to examine the effects of supplementation and dose of rumen-protected choline (RPC) on markers of inflammation and metabolism in liver and mammary tissue during an intramammary lipopolysaccharide (LPS) challenge. Parous Holstein cows were blocked by calving month and randomly assigned within block to receive 45 g/d of RPC (20.4 g/d of choline ions; CHOL45), 30 g/d of RPC (13.6 g/d of choline ions; CHOL30), or no RPC (CON) as a top-dress starting 24 d before expected calving until 21 d postpartum. Cows were alternately assigned within treatment group to either receive an intramammary LPS challenge (200 µg in each rear quarter; Escherichia coli O111:B4) or not at 17 DIM (CHOL45, n = 9; CHOL45-LPS, n = 9; CHOL30, n = 11; CHOL30-LPS, n = 10; CON, n = 10; CON-LPS, n = 9). Hepatic and mammary tissues were collected from all cows on d 17 postpartum. Hepatic and mammary tissues were collected at ∼7.5 and 8 h, respectively, after the LPS challenge. An additional mammary biopsy was conducted on LPS-challenged cows (CHOL45-LPS, CHOL30-LPS, and CON-LPS) at 48 h postchallenge. Hepatic and mammary RNA copy numbers were quantified for genes involved in apoptosis, methylation, inflammation, oxidative stress, and mitochondrial function using NanoString technology. Targeted metabolomics was conducted only on mammary tissue samples (both 8 and 48 h biopsies) to quantify 143 metabolites including choline metabolites, amino acids, biogenic amines and derivatives, organic acids, carnitines, and glucose. Hepatic IFNG was greater in CHOL45 as compared with CON in unchallenged cows, suggesting an improvement in type 1 immune responses. Hepatic CASP3 was greater in CHOL45-LPS as compared with CON-LPS, suggesting greater apoptosis. Mammary IL6 was reduced in CHOL30-LPS cows as compared with CHOL45-LPS and CON-LPS (8 and 48 h). Mammary GPX4 and COX5A were reduced in CHOL30-LPS as compared with CON-LPS (8 h), and SDHA was reduced in CHOL30-LPS as compared with CON-LPS (8 and 48 h). Both CHOL30-LPS and CHOL45-LPS cows had lesser mammary ATP5J than CON-LPS, suggesting that dietary RPC supplementation altered mitochondrial function following LPS challenge. Treatment did not affect mammary concentrations of any metabolite in unchallenged cows, and only 4 metabolites were affected by dietary RPC supplementation in LPS-challenged cows. Mammary concentrations of isobutyric acid and 2 acyl-carnitines (C4:1 and C10:2) were reduced in CHOL45-LPS as compared with CHOL30-LPS and CON-LPS. Taken together, reductions in medium- and short-chain carnitines along with an increase in long-chain carnitines in mammary tissue from CHOL45-LPS cows suggests less fatty acid entry into the ß oxidation pathway. Although the intramammary LPS challenge profoundly affected markers for inflammation and metabolism in liver and mammary tissue, dietary RPC supplementation had minimal effects on inflammatory markers and the mammary metabolome.

Pesticides luminescent sensing by a Tb3+-doped Zn metal-organic framework with selectivity towards parathion.

Organophosphorus pesticides (OPPs) such as parathion have extensive uses in agriculture and household applications. Chronic exposure to these pesticides can cause severe health and environmental issues. Therefore, a current ecological concern is associated with accumulating these noxious OPPs in food and water sources. In this work, a new Tb3+-doped Zn-LMOF (Zn-LMOF= (3D) {[Zn3(1,4 benzenedicarboxylate)3(EtOH)2]·(EtOH)0.6}∞) was synthesized by a solvent-free reaction between the Zn-LMOF and the salt TbCl3·6H2O using a high-speed ball milling. The Tb@Zn-LMOF was thoroughly characterized by multiple spectroscopic tools, including Scanning Electron Microscopy with Energy-Dispersive X-ray Spectroscopy, and studied in-depth as a luminescent sensor for a series of pesticides (parathion, malathion, methalaxil, carbofuran, iprodione, captan and glyphosate) in aqueous methanol. The Tb@Zn-LMOF is a long-lived green-emitting compound with luminescence originated by an efficient antenna effect from the excited energy levels of Zn-LMOF toward the 5D state of Tb3+ ions, as it is displayed by its strong emission bands at 488, 545, 585, and 620 nm and a lifetime of 1.01 ms upon excitation at 290 nm. Additions of pesticides to a neutral methanolic dispersion of Tb@Zn-LMOF modified its green emission intensity with a pronounced selectivity toward parathion within the micromolar concentration range. The detection limit for parathion was calculated to be 3.04 ± 0.2 µM for Tb@Zn-LMOF. Based on 31P NMR and mass spectrometry studies, it is attributed to the release of lanthanide ions from Tb@Zn-LMOF with the simultaneous formation of a Tb3+-parathion complex.

Biogenic synthesis of iron oxide nanoparticles using leaf extract of Spilanthes acmella: antioxidation potential and adsorptive removal of heavy metal ions.

The sequestration of contaminants from wastewater, such as heavy metals, has become a major global issue. Multiple technologies have been developed to address this issue. Nanotechnology is attracting significant interest as a new technology, and numerous nanomaterials have been produced for sequestrating heavy metals from polluted water due to their superior properties arising from the nanoscale effect. This study reports biosynthesis of iron oxide nanoparticles (IO-NPs) and their applications for adsorptive sequestration of various metal ions from aqueous solutions. Biosynthesis of IO-NPs has been carried out by using leaf extract of Spilanthes acmella, a medicinal plant. FTIR analysis of the leaf extract and biosynthesized IO-NPs marked the role of various functional groups in biosynthesis of IO-NPs. FESEM analysis revealed the average size range of IO-NPs as 50 to 80 nm, while polydisperse nature was confirmed by DLS analysis. EDX analysis revealed the presence of Fe, O, and C atoms in the elemental composition of the NPs. The antioxidant potential of the biosynthesized IO-NPs (IC50 = 136.84 µg/mL) was confirmed by DPPH assay. IO-NPs were also used for the adsorptive removal of As3+, Co2+, Cd2+, and Cu2+ ions from aqueous solutions with process optimization at an optimized pH (7.0) using dosage of IO-NPs as 0.6 g/L (As3+ and Co2+) and 0.8 g/L (Cd2+ and Cu2+). Adsorption isotherm analysis revealed the maximum adsorption efficiency for As3+ (21.83 mg/g) followed by Co2+ (20.43 mg/g), Cu2+ (15.29 mg/g), and Cd2+ (13.54 mg/g) using Langmuir isotherm model. The biosynthesized IO-NPs were equally efficient in the simultaneous sequestration of these heavy metal ions signifying their potential as effective nanoadsorbents.

An advanced treatment process for 3-high wastewater discharged from crude oil storage tanks.

The wastewater discharged from crude oil storage tanks (WCOST) contains high concentrations of salt and metal iron ions, and high chemical oxygen demand (COD). It belongs to "3-high" wastewater, which is difficult for purification. In this study, WCOST treatments were comparatively investigated via an advanced pretreatment and the traditional coagulation-microfiltration (CMF) processes. After WCOST was purified through the conventional CMF process, fouling occurred in the microfiltration (MF) membrane, which is rather harmful to the following reverse osmosis (RO) membrane unit, and the effluent featured high COD and UV254 values. The analysis confirmed that the MF fouling was due to the oxidation of ferrous ions, and the high COD and UV254 values were mainly attributable to the organic compounds with small molecular sizes, including aromatic-like and fulvic-like compounds. After the pretreatment of the advanced process consisting of aeration, manganese sand filtration, and activated carbon adsorption in combination with CMF process, the removal efficiencies of organic matter and total iron ions reached 97.3% and 99.8%, respectively. All the water indexes of the effluent, after treatment by the advanced multi-unit process, meet well the corresponding standard. The advanced pretreatment process reported herein displayed a great potential for alleviating the MF membrane fouling and enhanced the lifetime of the RO membrane system in the 3-high WCOST treatment.

Development of ZnO-GO-NiO membrane for removal of lead and cadmium heavy metal ions from wastewater.

The presence of heavy metal (HM) ions, such as lead, cadmium, and chromium in industrial wastewater discharge are major contaminants that pose a risk to human health. These HMs should separate from the wastewater to ensure the reuse of the discharged water in the process and mitigate their environmental impacts. The distinctive mechanical properties of 2D graphene oxide (GO), and the antifouling characteristics of metal oxides (ZnO/NiO) nanoparticles combined to produce composites supporting special features for wastewater treatment. This study employed solution casting and phase inversion methods to synthesize PSF-based GO, ZnO-GO, and ZnO-GO-NiO mixed matrix membranes and the effects of variation in composition on the removal of lead (Pb2+) and cadmium (Cd2+) ion was examined. Several characterization techniques including X-ray diffraction analysis, scanning electron microscopy, energy dispersive X-ray, and Fourier transform infrared spectroscopy were applied to analyze the synthesized NPs and MMMs. The composite membranes were also analyzed in terms of their porosity, permeability, hydrophilicity, surface roughness, zeta potential, thermal stability, mechanical strength, and flux regeneration at various transmembrane pressures (2-3 kgcm-2), and pH value (5.5). The highest adsorption capacities were measured to be 308.16 mg g-1 and 354.80 mg g-1 for Pb (II) and Cd (II), respectively, for membrane (M4_A) having 0.3 wt% of ZnO-GO-NiO nanocomposite, at 200 mg L-1 of feed concentration and 1.60 mL min-1 of permeate flux. The Pb (II) and Cd (II) adsorption breakthrough curves were created, and the results of the experiment were compared with the data of the Thomas model.

Rational development of a peptide-based probe for fluorescence and colorimetric dual-mode detection of Cu2+ and S2- ions: Real application in cell imaging and test strips.

A new dual-mode probe FAM-SSH with fluorescence and colorimetric properties was developed by solid-phase peptide synthesis, comprising 5-carboxy fluorescein (5-FAM) as a fluorophore, and tripeptide (Ser-Ser-His) as a recognition group. FAM-SSH not only displayed highly selective detection of Cu2+ based on fluorescence quenching mode, but also achieved colorimetric recognition of Cu2+ in solution, wherein a color change was observable to the naked eye. Additionally, the FAM-SSH-Cu2+ ensemble was highly selective for S2- over a wide pH range (7.0-12.0), characterized by a fluorescence enhanced response and colorimetric recognition, which was caused by the release of FAM-SSH and the precipitation of CuS. Moreover, the limit of detection (LOD) values for Cu2+ and S2- were 55.5 nM and 31.1 nM, respectively. Results of sample analyses and cell imaging experiments indicated that FAM-SSH has exciting field practicability and good cell permeability, and would be further useful for detection and imaging in environmental systems and living cells. Finally, test strips were produced by immersing them in FAM-SSH solution, thereby creating a method for portable visual detection. More importantly, a smartphone-assisted visual sensing platform was also developed for semi-quantitative Cu2+ and S2- detection with LOD values of 0.48 µM and 1.22 µM, respectively.

Self-assembling NBD-tripeptide as a dual-mode colorimetric platform for naked eye and smartphone joint detection of micro to nanomolar Copper(II) ions.

Compared to conventionally synthesized organic compounds, peptides with amphiphiles have unique advantages, especially in self-assembly. Herein, we reported a peptide-based molecule rationally designed for the visual detection of copper ions (Cu2+) in multiple modes. The peptide exhibited excellent stability, high luminescence efficiency, and environmentally responsive molecular self-assembly in water. In the presence of Cu2+, the peptide undergoes an ionic coordination interaction and a coordination-driven self-assembly process that leads to the quenching of fluorescence and the formation of aggregates. Therefore, the concentration of Cu2+ can be determined by the residual fluorescence intensity and the color difference between peptide and competing chromogenic agents before and after Cu2+ incorporation. More importantly, this variation in fluorescence and color can be presented visually, thus allowing qualitative and quantitative analysis of Cu2+ based on the naked eye and smartphones. Overall, our study not only extends the application of self-assembling peptides but also provides a universal method for dual-mode visual detection of Cu2+, which would significantly promote point-of-care testing (POCT) of metal ions in pharmaceuticals, food, and drinking water.

Valorised polypropylene waste based reversible sensor for copper ion detection in blood and water.

Heavy metals and plastic pollutants are the two most disastrous challenges to the environment requiring immediate actions. In this work, a techno-commercially feasible approach to address both challenges is presented, where a waste polypropylene (PP) based reversible sensor is produced to selectively detect copper ions (Cu2+) in blood and water from different sources. The waste PP-based sensor was fabricated in the form of an emulsion-templated porous scaffold decorated with benzothiazolinium spiropyran (BTS), which produced a reddish colour upon exposure to Cu2+. The presence of Cu2+ was checked by naked eye, UV-Vis spectroscopy, and DC (Direct Current) probe station by measuring the current where the sensor's performance remained unaffected while analysing blood, water from different sources, and acidic or basic environment. The sensor exhibited 1.3 ppm as the limit of detection value in agreement with the WHO recommendations. The reversible nature of the sensor was determined by cyclic exposure of the sensor towards visible light turning it from coloured to colourless within 5 min and regenerated the sensor for the subsequent analysis. The reversibility of the sensor through exchange between Cu2+- Cu+ was confirmed by XPS analysis. A resettable and multi-readout INHIBIT logic gate was proposed for the sensor using Cu2+ and visible light as the inputs and colour change, reflectance band and current as the output. The cost-effective sensor enabled rapid detection of the presence of Cu2+ in both water and complex biological samples such as blood. While the approach developed in this study provides a unique opportunity to address the environmental burden of plastic waste management, it also allows for the possible valorization of plastics for use in enormous value-added applications.

A microdots array-based fluoremetric assay with superwettability profile for simultaneous and separate analysis of iron and copper in red wine.

A microdots array-based fluoremetric method with superwettability profile has been developed for the simultaneous and separate detection of Fe3+ and Cu2+ ions in red wine samples. A wettable micropores array was initially designed with high density by using polyacrylic acid (PAA) and hexadecyltrimethoxysilane (HDS), followed by the NaOH etching route. Zinc metal organic frameworks (Zn-MOFs) were fabricated as the fluorescent probes to be immobilized into the micropores array to obtain the fluoremetric microdots array platform. It was found that the fluorescence of Zn-MOFs probes could decrease significantly in the presence of Fe3+ and/or Cu2+ ions towards their simultaneous analysis. Yet, the specific responses to Fe3+ ions could be expected if using histidine to chelate Cu2+ ions. Moreover, the developed Zn-MOFs-based microdots array with superwettability profile can enable the accumulation of targeting ions from the complicated samples without any tedious pre-processing. Also, the cross-contamination of different samples droplets can be largely avoided so as to facilitate the analysis of multiple samples. Subsequently, the feasibility of simultaneous and separate detection of Fe3+ and Cu2+ ions in red wine samples was demonstrated. Such a design of microdots array-based detection platform may promise the wide applications in analyzing Fe3+ and/or Cu2+ ions in the fields of food safety, environmental monitoring, and medical diseases diagnostics.

Infrared Spectroscopy to Analyze Sexual Dimorphism of Hard Dental Tissue Maturation at Eruption in Patients with Connective Tissue Dysplasia.

The aim of this study was to research the biochemical changes in the hard tissues of the lower "wisdom" teeth, which are at the stage of eruption, with connective tissue dysplasia, depending on sex. The study involved 38 patients aged 17-25 years, who had the extraction of the lower third molars on the left and right for medical reasons. Twenty-one participants in the experiment (16 females, five males) were diagnosed with connective tissue dysplasia; the remaining 17 were healthy and made up the control group (11 females, six males). Samples of enamel, dentin, and enamel-dentin junction were dried to constant weight and examined in tablets pressed in a mixture with potassium bromide on an FT-801 Fourier transform infrared (FT-IR) spectrometer (NPF Simex, Russia) in the range of 500-4000 cm-1. In the IR spectra of the enamel, enamel-dentin junction, and dentin, the absorbance ratio of amide I and II changed significantly and the absorbance of the absorption band of phosphate ions decreased from enamel to dentin. Differences between groups with and without connective tissue dysplasia increased in the following series: dentin, enamel-dentin junction, and enamel. With connective tissue dysplasia, a change in the ratio of the intensities of the absorption bands of amide I and phosphate ions was observed. Normally, the content of organic substances in the enamel of the teeth in the males group is lower than in the females group. Against the background of connective tissue dysplasia, the content of organic substances in the enamel in women decreased while in men it increased, which confirmed the presence of sexual dimorphism during the maturation of hard dental tissues at the eruption stage. The study confirms the opinion of many researchers about the significant role of collagen proteins, which, together with non-collagen proteins, are involved in the development and maturation of dental hard tissues, which are characterized by pronounced heterogeneity and sexual dimorphism in the group with connective tissue dysplasia.

Development of ratiometric fluorescent probes based on peptides for sensing Pb2+ in aquatic environments and human serum.

The detection of Pb2+ ions in aquatic environments and biofluid samples is crucial for assessment of human health. Herein, we synthesized two fluorescent probes (1 and 2) consisting of the peptide receptor for Pb2+ and a benzothiazolyl-cyanovinylene fluorophore that exhibited excimer-like emission when it aggregated. The peptide-based probes sensitively detected Pb2+ in purely aqueous solution (1% DMF) through ratiometric fluorescent response with a decrease in monomer emission at 520 nm and an increase in excimer emission at 570 nm. Specially, probe 2 showed remarkable detection features such as high selectivity for Pb2+over 15 metal ions, high binding affinity (Kd = 5.83 × 10-7 M) for Pb2+, significant emission intensity changes, low detection limit (3.8 nM) of Pb2+, high water solubility, and visible light excitation (450 nm). Probe 2 was successfully used to quantify nanomolar concentration (0 âˆ¼ 800 nM) of Pb2+ in real water samples (ground water and tap water). Specially, 2 was successfully applied for the quantification of Pb2+ in human serum by combination of microwave-assisted human serum digestion and filtration of digested serum by anion exchange cartridge. We clearly investigated the binding mode of 2 with Pb2+ using 1H NMR, IR spectroscopy, pH titration, confocal microscopy, and size analysis. The peptide-based fluorescent probe might have great application potential for sensing Pb2+ in aquatic environments and biofluid samples.

Extraction of extracellular polymeric substances (EPS) from indigenous bacteria of rare earth tailings and application to removal of thorium ions (Th4+).

Thorium, as an important radioactive element, is widely present in nature, and its accompanying environmental pollution is also serious. Extracellular polymeric substances (EPS) are commonly found on the surface of microbial bodies and have strong adsorption capacity for metal ions. In this study, four methods were used to extract EPS from indigenous bacteria of rare earth tailings and to determine the best extraction method. The extracted EPS was applied to treat Th4+, and the changes in functional groups and composition of EPS were investigated. The results showed that the ultrasonic method was more efficient than other methods. The best removal efficiency was observed at pH 3.5, Th4+ concentration of 20 mg/L, and EPS dosage of 30 mL at 25 °C. After 9 h, the adsorption process reached equilibrium with a maximum removal efficiency of 75.93% and a maximum theoretical adsorption capacity of 25.96 mg/g. The Th4+ removal process was consistent with the Langmuir and Freundlich adsorption isotherms and the kinetic data were consistent with the pseudo-second-order kinetic model, which is mainly based on chemisorption. Amide I and amide II of proteins, C-H from aliphatic, as well as O-H and C = O from carboxylic acid play important roles in the adsorption process.

Comprehensive profiling of chemical composition of Gleditsiae spina using ultra-high-performance liquid chromatography coupled with electrospray ionization quadrupole time-of-flight mass spectrometry.

RATIONALE: Gleditsiae spina (GS) is an important herb used in traditional and folk medicinal systems of East Asian countries for its various medicinal properties. In China, it has been traditionally used through the centuries for its anticancer, detoxication, detumescence, apocenosis, and antiparasitic effects. Although some of its ingredients have been isolated and identified, most active constituents remain unknown. Past research mostly exploited nuclear magnetic resonance for the identification of compounds, which is suitable for monomers only. Moreover, the extraction and isolation procedures for obtaining purified molecules are time consuming. Therefore, establishing an efficient approach will assist in rapid discovery of the potential active ingredients of GS. The present study aimed to identify the chemical constituents in GS by a data analysis strategy using ultra-high-performance liquid chromatography combined with quadrupole time-of-flight tandem mass spectrometry. METHODS: First, the theoretical formula of the candidate compound was calculated using the accurate mass of the precursor/adduct ions. Second, the compounds were classified by the diagnostic ions from the MS/MS data. Third, characteristic ion filtering was used to identify the structures. Finally, the diverse skeletons and substitutions were further identified through the neutral loss in the GS. RESULTS: A total of 277 compounds were identified in GS, comprising 169 flavonoids, 70 lignans, and 38 other compounds. At least 43 potential new compounds were represented. CONCLUSIONS: This experiment devised an efficient and systematic method for detecting complex compounds and provided a foundation for future research into bioactive ingredients and quality control of GS.

A feasibility study on production, characterisation and application of empty fruit bunch oil palm biochar for Mn2+ removal from aqueous solution.

Empty fruit bunch oil palm (EFBOP) is one of the byproducts after oil palm fruitlet is removed in oil palm processing and is considered as waste. In this study, EFBOP was converted to biochar (BC-EFBOP) at 350-700 °C, with an overarching aim of determining the feasibility of adsorptive removal of manganese (a second dominant element in acid mine drainage) from water. Results showed that with increasing temperature, the BC-EFBOP yield decreased from 44.34% to 26.74%, along with the H/C (0.89%-0.29%) and O/C ratios (0.38%-0.23%), and the carbon content increased (62.7%-73.93%). As evidenced by Fourier Transform InfraRed spectroscopy (FTIR) and X-ray Photoelectron Spectroscopy (XPS), abundant oxygen-containing surface functional groups such as hydroxyl (-OH), carboxyl (-COOH), and ether (C-O-C) were retained, and aromatic CC groups were largely generated in the biochar. Pyrolysed biochar at 350 °C (BC350), with the least surface area (0.5 m2 g-1), exhibited the highest Mn2+ adsorption capacity (8.2 mg g-1), whereas for BC700, with the largest surface area (2.19 m2 g-1), had the lowest capacity for Mn2+ (1.2 mg g-1). Regardless of the temperature, solution pH of 5 was found to be optimal for Mn2+ removal from water. The Langmuir isotherm model best described the equilibrium adsorption data with a maximum adsorption capacity of 1.2-8.2 mg g-1 for initial concentrations of 5-250 mg L-1, whereas the adsorption kinetics followed the pseudo-second-order model. There was nearly four-fold increase in Mn2+ ions removal with increased biochar dosage (0.05-0.5 g), at initial Mn2+ concentration of 100 mg L-1. The study showed that a low-cost, environmentally friendly BC-EFBOP with optimal surface chemistry could potentially remediate Mn2+ ions from aqueous media. However, a proper cost-benefit and techno-economic analysis is needed prior to potential pilot scale studies.

Nickel hydroxide nanoflower-based dispersive solid-phase extraction of copper from water matrix.

In this work, a dispersive solid-phase extraction method based on Ni(OH)2 nanoflowers (Ni(OH)2-NFs-DSPE) was developed to separate and preconcentrate copper ions from tap water samples for determination by flame atomic absorption spectrometry (FAAS). Ni(OH)2-NFs was synthesized using a homogeneous precipitation technique and used as sorbent for copper preconcentration. X-ray diffraction, scanning electron microscopy, and Fourier-transform infrared spectroscopy were used to characterize the synthesized sorbent. All experimental variables were carefully optimized to achieve a high enhancement factor of 107.5-folds with respect to the detection sensitivity of the conventional FAAS. The proposed method's analytical parameters including LOD, LOQ, and linear range were determined as 1.33 µg/L, 4.42 µg/L, and 3.0-40 µg/L, respectively. To assess the applicability and reliability of the developed method, optimal conditions were applied to tap water samples and satisfactory percent recoveries (94-103%) were obtained for the samples spiked at 20 and 30 µg/L. This validated the accuracy and feasibility of the developed method to real samples. The developed method can be described as a simple, efficient, and rapid analytical approach for the accurate determination of trace copper ions in water samples.