Sodium Salts Research Articles

An Application of Polymer Nanocomposites Based On Carboxymethylcellulose along with Aluminium (Al) and Copper (Cu) Nanoparticles for Increasing Oil Production

As an agent for displacing residual and hard-to-recover oil reserves, polymer nanocomposites based on sodium salts of carboxymethylcellulose (CMC) and aluminium (Al) and copper (Cu) nanoparticles were investigated. It has been shown that polymer nanocomposites are more effective as oil displacement agents than the sodium salt of carboxymethylcellulose itself. Increasing the viscosity of an oil displacement solution can be achieved by varying the concentrations of CMC and nanoparticles. This study thoroughly examined the dynamic viscosities of carboxymethylcellulose (CMC) and polymer nanocomposites that contain CMC and metal nanoparticles (Al and Cu) across various concentrations. The results obtained are robust and reliable. It has been shown that, among polymer nanocomposites containing Al nanoparticles, there is a higher dynamic viscosity compared to its Cu nanoparticle counterpart at equivalent concentrations. This work proposes a simulation reservoir model to enhance oil recovery from hard-to-recovery reserves. Through this reservoir model simulation, the oil recovery factor was calculated using filler sand and oil extracted from a hydrocarbon field. The experimental data revealed the most effective concentration of CMC and nanoparticles for oil displacement. The results suggest that polymer nano composites composed of different metal nano powders have varying impacts on oil displacement efficiency. In this experiment, a composition consisting of Al nanoparticles with a size range of 50-70 manometers (nm) proved to be more successful as an oil displacement agent than a polymer nanocomposite made of Cu nanoparticles and CMC. At these concentrations and combinations, the highest oil recovery factors were achieved.

A mass transfer study of CO2 absorption in aqueous solutions of isomeric forms of sodium alaninate for direct air capture application

Direct air capture (DAC) of CO2 is a critical emerging technology required to achieve ambitious net-zero emissions. Aqueous amino acid absorbents are ideal candidates for DAC and this work describes the investigation of the CO2 absorption performance of sodium salts of β- and α-alaninate under relevant conditions for DAC by utilising synthetic CO2 gas streams at concentrations levels found in the atmosphere (200–600 ppm). The effects of solution concentration, temperature, gas flowrate, liquid flowrate, and dissolved CO2 concentration (i.e., CO2 loading) on CO2 mass transfer coefficients were investigated. The overall mass transfer coefficient was found to be independent of the gas and liquid flowrates, with larger values determined for β-alaninate solutions (0.75–1.16 mmol m−2 s−1 kPa−1) than that of α-alaninate (0.65–0.87 mmol m−2 s−1 kPa−1), under similar experimental conditions. The results showed that the overall mass transfer coefficient increases with increasing temperature, conversely decreasing steadily with increasing CO2 loading. The maximum CO2 loading capacity of the 5.0 M solutions was ∼10 % higher for β-alanine (0.651 mol CO2/mol alaninate) than α-alanine (0.607 mol CO2/mol alaninate) at 25.0 °C. Precipitation was found to play an important role in the CO2 absorption processes here. Interestingly, beyond CO2 loadings >0.12 mol CO2/mol α-alaninate, the 5.0 M solution of α-alaninate begins to develop precipitate(s) while precipitation in the β-alaninate solution is only initiated at much higher CO2 loadings >0.52 mol CO2/mol β-alaninate. This study provides valuable insights into the suitability of β-alanine and α-alanine for CO2 capture directly from the ambient air.

INFLUENCE OF POLAR MODIFIERS ON THE ANIONIC SOLUTION 1,3-BUTADIENE POLYMERIZATIONS

ABSTRACT This work addresses the critical technological challenge of producing butadiene-based synthetic rubbers with the required skid resistance through anionic polymerizations at positive temperatures. The effects of adding different polar modifiers—bis[2-(N,N-dimethylamino)ethyl] ether (BDMAE), ditetrahydrofurylpropane, tetramethylethylenediamine, sodium stearate, sodium palmitate, and sodium tert-amilate—into the monomer feed in anionic solution polymerizations of 1,3-butadiene are investigated. Different feed concentrations and combinations of polar modifiers were tested to achieve high yields and vinyl contents with initial temperature of 40 °C. The reactions were evaluated according to the obtained temperature and pressure profiles and physico-chemical characterizations of the obtained polymer, with the aid of statistical analyses. The results clearly showed the positive effects of using polar modifiers in the feed. Particularly, the combination of BDMAE and sodium salts provided products with high vinyl contents (>50%mol) with high yields (>80 wt%), leading to high temperature peaks (>90 °C), as desired to enhance skid resistance. Moreover, the performed statistical analyses and proposed mathematical modeling revealed the existence of multivariate and complex correlations among the analyzed process variables. The findings from this investigation can be pivotal for advancing industrial applications in the production of skid-resistant synthetic rubber.

Cross-Linked Alginate Dialdehyde/Chitosan Hydrogel Encompassing Curcumin-Loaded Bilosomes for Enhanced Wound Healing Activity.

The current study aimed to fabricate curcumin-loaded bilosomal hydrogel for topical wound healing purposes, hence alleviating the poor aqueous solubility and low oral bioavailability of curcumin. Bilosomes were fabricated via the thin film hydration technique using cholesterol, Span® 60, and two different types of bile salts (sodium deoxycholate or sodium cholate). Bilosomes were verified for their particle size (PS), polydispersity index (PDI), zeta potential (ZP), entrapment efficiency (EE%), and in vitro drug release besides their morphological features. The optimum formulation was composed of cholesterol/Span® 60 (molar ratio 1:10 w/w) and 5 mg of sodium deoxycholate. This optimum formulation was composed of a PS of 246.25 ± 11.85 nm, PDI of 0.339 ± 0.030, ZP of -36.75 ± 0.14 mv, EE% of 93.32% ± 0.40, and the highest percent of drug released over three days (96.23% ± 0.02). The optimum bilosomal formulation was loaded into alginate dialdehyde/chitosan hydrogel cross-linked with calcium chloride. The loaded hydrogel was tested for its water uptake capacity, in vitro drug release, and in vivo studies on male Albino rats. The results showed that the loaded hydrogel possessed a high-water uptake percent at the four-week time point (729.50% ± 43.13) before it started to disintegrate gradually; in addition, it showed sustained drug release for five days (≈100%). In vivo animal testing and histopathological studies supported the superiority of the curcumin-loaded bilosomal hydrogel in wound healing compared to the curcumin dispersion and plain hydrogel, where there was a complete wound closure attained after the three-week period with a proper healing mechanism. Finally, it was concluded that curcumin-loaded bilosomal hydrogel offered a robust, efficient, and user-friendly dosage form for wound healing.

Global transcriptome analysis of Pseudomonas aeruginosa NT06 response to potassium chloride, sodium lactate, sodium citrate, and microaerophilic conditions in a fish ecosystem.

Pseudomonas aeruginosa is an opportunistic pathogen that recently has been increasingly isolated from foods, especially from minimally processed fish-based products. Those are preserved by the addition of sodium chloride (NaCl) and packaging in a modified atmosphere. However, the current trends of minimizing NaCl content may result in an increased occurrence of P. aeruginosa. NaCl can be replaced with potassium chloride (KCl) or sodium salts of organic acids. Herein, we examined the antimicrobial effects of KCl, sodium lactate (NaL), sodium citrate (NaC), and sodium acetate (NaA) against P. aeruginosa NT06 isolated from fish. Transcriptome response of cells grown in medium imitating a fish product supplemented with KCl and KCl/NaL/NaC and maintained under microaerophilic conditions was analysed. Flow cytometry analysis showed that treatment with KCl and KCl/NaL/NaC resulted in changed metabolic activity of cells. In response to KCl and KCl/NaL/NaC treatment, genes related to cell maintenance, stress response, quorum sensing, virulence, efflux pump, and metabolism were differentially expressed. Collectively, our results provide an improved understanding of the response of P. aeruginosa to NaCl alternative compounds that can be implemented in fish-based products and encourage further exploration of the development of effective methods to protect foods against the P. aeruginosa, underestimate foodborne bacteria.

Study on the Anti-Ulcerative Colitis Effect of Pseudo-Ginsenoside RT4 Based on Gut Microbiota, Pharmacokinetics, and Tissue Distribution.

The purpose of this study was to explore the therapeutic effect of the oral administration of pseudo-ginsenoside RT4 (RT4) on ulcerative colitis (UC), and to determine the rate of absorption and distribution of RT4 in mice with UC. Balb/c mice were induced using dextran sulfate sodium salts (DSS) to establish the UC model, and 10, 20, or 40 mg/kg of RT4 was subsequently administered via gavage. The clinical symptoms, inflammatory response, intestinal barrier, content of total short-chain fatty acids (SCFAs), and gut microbiota were investigated. Caco-2 cells were induced to establish the epithelial barrier damage model using LPS, and an intervention was performed using 4, 8, and 16 µg/mL of RT4. The inflammatory factors, transient electrical resistance (TEER), and tight-junction protein expression were determined. Finally, pharmacokinetic and tissue distribution studies following the intragastric administration of RT4 in UC mice were performed. According to the results in mice, RT4 decreased the disease activity index (DAI) score, restored the colon length, reduced the levels of pro-inflammatory cytokines (TNF-α, IL-6, and IL-1β), and boosted the levels of immunosuppressive cytokine IL-10, increased the content of SCFAs, improved the colonic histopathology, maintained the ultrastructure of colonic mucosal epithelial cells, and corrected disturbances in the intestinal microbiota. Based on the results in caco-2 cells, RT4 reduced the levels of TNF-α, IL-6, and IL-1β; protected integrity of monolayers; and increased tight-junction protein expression. Additionally, the main pharmacokinetic parameters (Cmax, Tmax, t1/2, Vd, CL, AUC) were obtained, the absolute bioavailability was calculated as 18.90% ± 2.70%, and the main distribution tissues were the small intestine and colon. In conclusion, RT4, with the features of slow elimination and directional distribution, could alleviate UC by inhibiting inflammatory factors, repairing the intestinal mucosal barrier, boosting the dominant intestinal microflora, and modulating the expression of SCFAs.

N-SALICYLOYL AMIDES AND THEIR SALTS: SYNTHESIS, BIOLOGICAL ACTIVITY AND TOXICITY

The Schotten-Baumann reaction was used to synthesize N-salicyloyl derivatives of Morpholine, Glycine and gamma-aminobutyric acid in the process between salicyloyl chloride with morpholine, glycine or gamma-aminobutyric acid with high yield. Sodium and lithium salts of the salicylamides were synthesized by the reaction of an amide with sodium ethylate or lithium hydroxide in inert solvent. The synthesized compounds were charachterized by 1H nuclear magnetic resonance spectra and elemental analysis. Purity was checked by thin layer chromatography. Quantitative analysis of metal ions was done by potentiometry. To select the most promising compounds exhibiting psychotropic (Pa > 0.8) and antiviral (Pa about 0.5) activities, computer analysis was carried out through the PASS program. In the present study, psychotropic (the open-field exploratory test, the forced swim test, the elevated plus-maze test, the passive avoidance test), analgesic (current vocalization threshold) activities and acute toxicity were evaluated. The results of psychotropic activity revealed that amides possess significant psychotropic activity and low acute toxicity. Disodium salicylurate showed a significant antiamnesic action. The results suggested a significant antidepressant activity and antiamnesic action for dilithium salicylurate and sodium salt of salycyloyl morphlide, a psychostimulant action for lithium salt of salicyloyl morphlide. Lithium gamma-(N-salycylamino)butyrate demonstrated psychostimulant and antiamnesic activities. Our present investigation demonstrated that all compounds are very safe for consumption with high LD50 value. All obtained compounds were evaluated for their antiviral activities against a large number of DNA and RNA viruses including herpes simplex viruses 1 and 2, vaccinia virus, vesicular stomatitis virus, HIV-1 and HIV-2. These compounds were evaluated against human cervix carcinoma cells (HeLa) and CEM T-lymphocytes as well as murine leukemia cells (L1210). The antiviral activity studies depicted that none of the tested compounds were active against DNA or RNA viruses.

Surface modification of die steels by liquid boriding

The research investigates the effect of liquid boriding on the microstructure, composition and microhardness of the surface layer on 5KhNM and 3Kh2V8F die steels. Boriding was carried out for 8 hours at 850 and 1000 °С in a melt based on sodium tetraborate and sodium salts. After high-temperature exposure during the boriding process, the samples were quenched in oil and tempered. Next, the samples were subjected to metallographic, X-ray spectral, X-ray diffraction and durometric analyses. As a result of processing, boride diffusion layers were obtained on the surface of 5KhNM and 3Kh2V8F steels up to 100 and 130 μm thick, respectively. It has been established that iron borides Fe2B and FeB are formed on the surface of both steels. In addition, chromium boride CrB is additionally formed on the surface of 5KhNM steel, increasing the maximum microhardness of the layer to 2130 HV. The maximum microhardness of 3Kh2V8F steel reaches 1709 HV due to the formation of borides and carbides in the layer. A study of the surface topography after boriding showed that the roughness parameter Ra of 5KhNM steel increased by 1.87 times, and of 3Kh2V8F steel by 1.78 times compared to the initial state.

Design, synthesis, analgesic, antibacterial and docking studies of novel 8-piperazinylcaffeine carboxylate ionic liquids.

This paper presents a comprehensive evaluation of novel 8-piperazinylcaffeine carboxylate ionic liquids, including their design, synthesis, characterization, analgesic and antibacterial properties, as well as docking studies. These unique salts were produced by combining 8-piperazinyl caffeine (8-PC) with various carboxylic acids, some of which are commonly used nonsteroidal anti-inflammatory drugs (NSAIDs). Through in vivo experiments on female mice using the formalin test, the analgesic efficacy of different 8-PC salts with various NSAIDs was assessed. Results demonstrated that a majority of these salts exhibited significant analgesic activity when compared to NaIBP, a standard reference drug. Particularly noteworthy was the enhanced analgesic effect of the 8-PC's NSAIDs salts (11a, 11c-e, and 11k) compared to their corresponding sodium salts, which was attributed to the presence of the 8-PC cation (synergistic effect). Furthermore, all synthesized salts were subjected to in vitro testing against Gram-positive Staphylococcus aureus (PTCC 1133), Gram-negative Pseudomonas aeruginosa (ATCC 27853), and Escherichia coli (PTCC 1330) bacteria. Among them, salt 11k displayed notable antibacterial activity, especially against P. aeruginosa, a dangerous opportunistic pathogen. Additionally, docking analysis revealed strong binding of the synthesized 8-PC and NSAID salts to the active site of the COX-2 enzyme.

Features of using bentonite clay of the Darbazа deposit for wastewater treatment of petrochemical productions

This article applies the method of sorption treatment of wastewater from petrochemical production with a sorbent based on bentonite clay from the Darbazа deposit.In connection with the increase in consumption and discharge of wastewater by industrial facilities in our country, the issue of purification of emissions, wastewater, and the introduction of closed production cycles are the main methods of improving environmental quality. One of the largest industrial enterprises, during the operation of which washing wastewater is generated, is the largest oil refinery (PetroKazakhstanOilProducts), located in Shymkent, as well as petrochemical industry enterprises. Some of the largest industrial enterprises are the oil refining and petrochemical industries. As is known, enterprises in this industry have a negative impact on the environmental situation in many regions of Kazakhstan, polluting the air, water bodies, and soil. The results obtained during the experiment proved the effectiveness of the sorbent in relation to chemical oxygen demand and petroleum products in the analyzed solutions. To carry out the sorption process, bentonite clay, which was selected as a sorbent material, was subjected to chemical activation using sodium salts. Based on the results obtained, we can conclude that the purification efficiency for activated bentonite with NaCl in terms of chemical oxygen demand is 82.85%, for petroleum products - 89.45%, and the purification efficiency for activated bentonite with Na2 CO3 reaches 85.41% for chemical oxygen demand, for petroleum products - 89.78%.

Reductive activation of arenes by potassium metal with potassium salts

Reaction of benzene with potassium metal + potassium salts leads to formation of biphenyl and dihydrobiphenyls via dimerization of arene radical anions. Sodium salts are much less effective.

Selective sodium halide over potassium halide binding and extraction by a heteroditopic halogen bonding [2]catenane.

The synthesis and ion-pair binding properties of a heteroditopic [2]catenane receptor exhibiting highly potent and selective recognition of sodium halide salts are described. The receptor design consists of a bidentate halogen bonding donor motif for anion binding, as well as a di(ethylene glycol)-derived cation binding pocket which dramatically enhances metal cation affinity over previously reported homo[2]catenane analogues. 1H NMR cation, anion and ion-pair binding studies reveal significant positive cooperativity between the cation and anion binding events in which cation pre-complexation to the catenane subsequently 'switches-on' anion binding. Notably, the heteroditopic catenane displayed impressive selectivity for sodium halide recognition over the corresponding potassium halides. We further demonstrate that the catenane is capable of extracting solid alkali metal salts into organic media. Crucially, the observed solution phase binding selectivity for sodium halides translates to superior functional extraction capabilities of these salts relative to potassium halides, overcoming the comparatively higher lattice enthalpies NaX > KX dictated by the smaller alkali metal sodium cation. This is further exemplified in competitive solid-liquid experiments which revealed the exclusive extraction of sodium halide salts from solid mixtures of sodium and potassium halide salts.

GRAVITATIONAL GEOLOGICAL PROCESSES (KARST)

The article presents karsts, as one of the gravitational geological processes, developing in rocks (limestone, dolomite, gypsum, anhydrite, sodium and potassium salts) dissolving in natural surface and groundwater. For the first time, an attempt was made to study karsts, changes in hydrogeological conditions during their development and the influence on internal and external hazardous geological phenomena. The main purpose of this article is to draw attention to the need for further study of the Dvin earthquake source, associated with the possible collapse of underground voids (in this case, karst halls) characteristic of this territory.

Lithium chloride selective ion-pair recognition by heteroditopic [2]rotaxanes.

The first heteroditopic [2]rotaxane host systems capable of strong and selective binding of lithium chloride ion-pair species are described. Importantly, a cooperative 'switch on' mechanism was found to operate, in which complexation of a lithium metal cation enhances the halide anion affinity of the rotaxanes via a combination of favourable proximal electrostatic and preorganised allosteric effects. The mechanically bonded rotaxane host design features a macrocycle component possessing a 2,6-dialkoxy pyridyl cation binding motif and an isophthalamide anion binding group, as well as an axle component functionalised with either a halogen bonding (XB) iodotriazole or hydrogen bonding (HB) prototriazole moiety. Extensive quantitative 1H NMR titration studies in CD3CN/CDCl3 solvent mixtures determined enhanced ion-pair binding affinities for lithium halides over the corresponding sodium or potassium halide salts, with the axle prototriazole-containing HB rotaxane in particular demonstrating a marked selectivity for lithium chloride. Solid-state X-ray crystallographic studies and computational DFT investigations provide evidence for a [2]rotaxane host axle-separated ion-pair binding mode, in which complementary cation and anion binding motifs from both the macrocycle and axle components act convergently to recognise each of the charged guest species.

Clinical Profile and Prevalence of Hyponatremia in Critically-ill Patients of All Age Groups

Hyponatremia is defined as a serum sodium level of <135 mEq/L. It is the most prevalent electrolyte imbalance encountered in hospital admissions around the world. Hyponatremia has been reported to be present in between 3.4% to 39.4% of hospital admissions, and it is substantially more prevalent in an Intensive Care Unit (ICU). It has been connected to an increase in mortality, hospital stays, and morbidity. An imbalance of specific ionised salts (sodium, potassium, calcium, bicarbonate, and chloride) in the blood is known as an electrolyte problem. Volume abnormalities are the main cause of disturbances in salt homeostasis, which largely produce neurologic symptoms. Serious consequences arise when these electrolyte imbalances worsen, which are frequent clinical issues in the ICU. Hyponatremia has a multifaceted aetiology and it can be of three types: euvolemic, hypovolemic, or hypervolemic hyponatremia. Regardless of being a frequently encountered electrolyte disturbance, hyponatremia is poorly acknowledged. Its relationship with a myriad of fundamental illnesses and its many aetiologies with varying pathological and physiological pathways make diagnosis problematic. Clinicians should be skilled at recognising the symptoms, causes, and aetiologies of hyponatremia when treating sick patients. The signs, symptoms, and causes of hyponatremia should be readily apparent to clinicians treating unwell patients. The present review focuses on the symptoms and clinical findings of hyponatremia in the critically-ill patient and discusses the types, pathophysiology, and clinical profile of these patients.

Mild hydrolysis of chemically stable valerolactams by a biocatalytic ATP-dependent system fueled by metaphosphate.

Medium-sized 5- and 6-membered ring lactams are molecules with remarkable stability, in contrast to smaller β-lactams. As monomers, they grant access to nylon-4 and nylon-5, which are alternative polyamides to widespread caprolactam-based nylon-6. Chemical hydrolysis of monocyclic γ- and δ-lactams to the corresponding amino acids requires harsh reaction conditions and up to now, no mild (enzymatic) protocol has been reported. Herein, the biocatalytic potential of a pair of heterologously expressed bacterial ATP-dependent oxoprolinases - OplA and OplB - was exploited. Strong activity in the presence of excess of ATP was monitored on δ-valerolactam and derivatives thereof, while trace activity was detected on γ-butyrolactam. An ATP recycling system based on cheap Graham's salt (sodium metaphosphate) and a polyphosphate kinase allowed the use of catalytic amounts of ATP, leading to up to full conversion of 10 mM δ-valerolactam at 30 °C in aqueous medium. Further improvements were obtained by co-expressing OplA and OplB using the pETDuet1 vector, a strategy which enhanced the soluble expression yield and the protein stability. Finally, a range of phosphodonors was investigated in place of ATP. With acetyl phosphate and carbamoyl phosphate, turnover numbers up to 176 were reached, providing hints on a possible mechanism, which was studied by 31P-NMR.

Ultra-strong, nonfreezing, and flexible strain sensors enabled by biomass-based hydrogels through triple dynamic bond design.

Biomass-based hydrogels have displayed excellent potential in flexible strain sensors due to their adequacy, biocompatibility, nontoxic and degradability. Nevertheless, their inferior mechanical properties, particularly at cryogenic temperatures, impeded their extensive utilization. Herein, we reported a rationally designed strain sensor fabricated from a gelatin and cellulose-derived hydrogel with superior mechanical robustness, cryogenic endurance, and flexibility, owing to a triple dynamic bond strategy (TDBS), namely the synergistic reinforcement among potent hydrogen bonds, imine bonds, and sodium bonds. Beyond conventional sacrificing bonds consisting of hydrogen bonds, dynamic covalent bonds and coordinate bonds, synergetic triple dynamic bonds dominated by strong hydrogen bonds and assisted by imine and sodium bonds with higher strength can dissipate more mechanical energy endowing the hydrogel with 38-fold enhancement in tensile strength (6.4 MPa) and 39-fold improvement in toughness (2.9 MPa). We further demonstrated that this hydrogel can work as a robust and biodegradable strain sensor exhibiting remarkable flexibility, broad detection range, considerable sensitivity and excellent sensing stability. Furthermore, owing to the improved nonfreezing performance achieved from incorporating sodium salts, the sensor delivered outstanding sensing properties under subzero conditions such as -20 and -4 °C. It is anticipated that the TDBS can create diverse high-performance soft-electronics for broad applications in human-machine interfaces, energy and healthcare.

Critical assessment of interactions between ct-DNA and choline-based magnetic ionic liquids: evidences of compaction.

Ionic liquids (ILs) have become an alternative green solvent for storage and for stability of DNA. However, an in-depth understanding of binding and molecular interactions between ILs and DNA is needed. In this respect, magnetic ILs (MILs) are promising due to their tunable physicochemical properties. Various spectroscopic techniques and molecular simulations have been employed to unravel the critical factors of the strength and binding mechanism of MILs with DNA. UV-vis spectra unravel the multimodal binding of MILs with DNA, and the intrusion of IL molecules into the minor groove of DNA has been observed from dye displacement studies. Fluorescence correlation spectroscopic studies and scanning electron microscopy confirm the compaction of the DNA. ITC and molecular docking studies estimate the binding affinity of DNA with MILs, of ∼7 kcal mol-1. The 1 μs long-MD simulations give insight into the structural changes in the DNA in the MIL environment. Due to strong interaction with choline ions in the close vicinity, DNA helixes bend or squeeze in length and dilate in diameter (elliptical → spherical), leading to compaction. The post-MD parameters suggest a stronger interaction with [Ch]2[Mn] IL than with [Ch][Fe] IL; hence, the former induces DNA compaction to a more significant extent. Furthermore, decompaction is observed with the addition of sodium salts and is characterized using spectroscopic methods.

Efficacy of three bioinsecticides for control of Colorado potato beetle on potatoes

An experiment was conducted to evaluate the effectiveness of three commercial bioinsecticides based on the spores of Bacillus thuringiensis var. thuringiensis. The control areas were areas where no protective measures were applied. The data showed that all bioinsecticides tested were highly effective against first, second and third instar larvae of the Colorado potato beetle Leptinotarsa decemlineata. The drug “Bitoxibacillin” ensured 100% death of larvae on day 8 at a drug concentration of 10 g/l. Combined preparation “Bitoxibacillin + GUMI” containing spores of Bacillus thuringiensis var. thuringiensis and sodium salts of humic acids, led to 100% death of larvae on the 7th day of observation. As the dosage of the drug was reduced to 5 mg/L, its effectiveness decreased to a 92% mortality rate within 9 days. The complex drug “Bitoxibacillin + Actarofid” contributed to 100% death of Colorado potato beetle larvae of all ages on the 7th day of observation at a concentration of 10 g/l. During the same time interval, 82% and 94% of the larvae died at drug concentrations of 2 mg/l and 5 mg/l, respectively.

Dual role of arsenite in hydrolysis and post-hydrolysis fluorescence sensing of selective pH-dependent probes.

In comparison to the sensing activity, the reactivity of arsenite (AsO2-) is less explored. Herein, we focused on AsO2- reactivity studies based on its pKa and compared the study with other common anions. All three pKa values of arsenite are >9.0, affording a flexible working pH range to design a probe for reactivity studies. We designed and synthesized six pH dependent benzothiazole-based Schiff bases, namely, 1-(((6-nitrobenzo[d]thiazol-2-yl)imino)methyl)naphthalen-2-ol (1), 5-(diethylamino)-2-(((6-nitrobenzo[d]thiazol-2-yl)imino)methyl)phenol (2), 9-(((6-nitrobenzo[d]thiazol-2-yl)imino)methyl)-2,3,6,7-tetrahydro-1H,5H-pyrido[3,2,1-ij]quinolin-8-ol (3), 5-methoxy-2-(((6-nitrobenzo[d]thiazol-2-yl)imino)methyl)phenol (4), 4-(((6-nitrobenzo[d]thiazol-2-yl)imino)methyl)benzene-1,3-diol (5), and 2-(((6-nitrobenzo[d]thiazol-2-yl)imino)methyl)phenol (6), as probes for hydrolysis studies containing 5% water in acetonitrile. In spite of the presence of water in the solution, no hydrolysis was observed for all the probes in the absence of a salt. In the presence of selected sodium salts of various anions in solution, intramolecular charge transfer (ICT) was observed after the deprotonation of an aromatic hydroxy group at the ortho position with respect to the imine groups within the probes. Among the studied anions, selective AsO2- induced imine hydrolysis was observed for probes 1 and 4. In the case of 5 with both o- and p-hydroxy groups, no hydrolysis was observed in the presence of AsO2-. Probe 6 with only the o-hydroxy group showed very fast hydrolysis with poor selectivity. The p-hydroxy group in 4-(((6-nitrobenzo[d]thiazol-2-yl)imino)methyl)phenol (7) resulted in poor AsO2- induced hydrolysis. The aldehyde, which was generated after hydrolysis of probe 1, showed selective emission at 450 nm in the presence of AsO2-. The time dependent hydrolysis reaction of probe 1 controls the emission intensity enhancement.