Molar Range Research Articles

Mandibular second molar impaction: introducing a novel and validated 3D classification system

BackgroundMandibular second molar (M2M) impaction is a clinically significant manifestation of eruption disturbance in dental development. The primary aim of this study was to investigate the impact of the three-dimensional (3D) characterization on clinical and therapeutic decisions for M2M impaction. The secondary aim was to introduce a validated 3D classification system incorporating both surgical and orthodontic parameters.MethodsBidimensional (2D) and 3D radiological records of 15 impacted M2M were collected and deidentified. Ten experienced clinicians (5 oral surgeons;5 orthodontists) categorized each case, first based on 2D records and then with 3D scans. The degree of orthodontic and surgical difficulty in treating impacted M2M was evaluated using a novel classification system based on anatomical and radiological features. The primary outcome variable was the assessment of differences in diagnosis and decision-making protocol using 2D or 3D records, where clinical relevance ranged from 0 to 4. The secondary outcome variable was the validation analysis of the proposed 3D classification system to determine the concordance among the clinicians. Descriptive statistics and multivariable inferential analysis based on Akaike information criterion (AIC) were performed (α = 0.05).Results3D examination allowed a better visualization of M2M impaction with higher clinical relevance for diagnosis of M2M root relationship to alveolar nerve and lingual plate, height to alveolar crest, depth, and inclination relative to the first molar and position relative to the third molar (range:2.69–3.43). The proposed 3D classification of M2M impaction changed clinical decisions regarding surgical-orthodontic approach, biomechanics, patient education, and treatment time estimate (range:2.59–3.33). In the validation analysis of the classification, no evidence of inter- or intra-group (surgeon/orthodontist) bias in score attribution occurred: the model with the minimum AIC was the null model (AIC = 718.04).Conclusion3D evaluation of impacted M2Ms could enhance diagnostic accuracy, and a classification system was proposed and validated by a group of experienced surgeons and orthodontists with high concordance.

Theoretical investigation of potential energetic material CL-20/TNBP co-crystal explosive based on molecular dynamics method.

The exploration of CL-20 eutectic has been a subject of fervent interest within the realm of high-energy material modification. Through the utilization of density functional and molecular dynamics methods, an investigation into the characteristics of hexanitrohexaazaisowurtzitane (CL-20)/4,4',5,5'-tetranitro-2H,2'H-3,3'-bipyrazole (TNBP)within the molar ratio range of 4:1-1:4 was conducted. This inquiry encompassed the scrutiny of molecular interaction pathways, attachment force, initiating molecular distance, unified energy concentration, and physical characteristics. Furthermore, the EXPLO-5 was harnessed to prognosticate the explosion features and byproducts of unadulterated CL-20, TNBP, and CL-20/TNBP frameworks. The findings delineate a substantial differentiation in the electrostatic charge distribution on the surface between CL-20 and TNBP particles, signifying the preeminence of intermolecular interactions between disparate entities over those within similar entities, thus intimating the plausibility of the eutectic constitution. Remarkably, the identification of maximal attachment force at a molar ratio of 1:1 suggests the heightened likelihood of eutectic formation, propelled primarily by electrostatic and van der Waals forces. The resultant eutectic explosive evinces intermediate reactivity and exemplary mechanical attributes. Moreover, the detonation achievement of the eutectic with a molar proportion of 1:1 straddles that of CL-20 and TNBP, representing a new type of insensitive high-energy material. The testing method employs the Materials Studio software and utilizes the molecular dynamics (MD) method to predict the properties of CL-20/TNBP cocrystals with different ratios and crystal faces. The MD simulation time step is set to 1fs, and the total MD simulation time is 2ns. An isothermal-isobaric (NPT) ensemble is used for the 2ns MD simulation. The COMPASS force field is employed, with the temperature set to 295K. The prediction of detonation characteristics and products is conducted using the EXPLO-5 software.

Theoretical study of potential energetic material CL-20/DNAN eutectic explosive based on molecular dynamics method.

The exploration of CL-20 eutectic has been a subject of fervent interest within the realm of high-energy material modification. Through the utilization of density functional and molecular dynamics methods, an investigation into the characteristics of hexanitrohexaazaisowurtzitane (CL-20)/2,4-dinitroanisole (DNAN) within the molar ratio range of 9:1-1:9 was conducted. This inquiry encompassed the scrutiny of molecular interaction pathway, attachment force, initiating molecular distance, unified energy concentration, and physical characteristics. Furthermore, EXPLO-5 was harnessed to prognosticate the explosion features and byproducts of unadulterated CL-20, DNAN, and CL-20/DNAN frameworks. The findings delineate a substantial differentiation in the electrostatic charge distribution on the surface between CL-20 and DNAN particles, signifying the preeminence of intermolecular interactions between disparate entities over those within similar entities, thus intimating the plausibility of eutectic constitution. Remarkably, the identification of maximal attachment force at a molar ratio of 4:6 suggests the heightened likelihood of eutectic formation, propelled primarily by electrostatic and van der Waals forces. The resultant eutectic explosive evinces intermediate reactivity and exemplary mechanical attributes. Moreover, the detonation achievement of the eutectic with a molar proportion of 4:6 straddles that of CL-20 and DNAN, representing a new type of insensitive high-energy material. The testing method employs the Materials Studio software and utilizes the molecular dynamics (MD) method to predict the properties of CL-20/DNAN co-crystals with different ratios and crystal faces. The MD simulation time step is set to 1 fs, and the total MD simulation time is 2 ns. An isothermal-isobaric (NPT) ensemble is used for the 2-ns MD simulation. The COMPASS force field is employed, with the temperature set to 295 K. The prediction of detonation characteristics and products is conducted using the EXPLO-5 software.

The retention factors and partial molar volumes of cycloartenyl ferulate at infinite dilution in supercritical carbon dioxide: Measurements and correlation

The retention factors and infinite dilution partial molar volumes of a solute in supercritical fluid are crucial for understanding solute–solvent interactions, analyzing pressure effects on chemical reactions, and optimizing industrial processes. Despite their importance, there is a notable scarcity of available data on retention factors and infinite dilution partial molar volumes in supercritical fluid systems. This study presents the first experimental data on the retention factors and partial molar volumes of cycloartenyl ferulate at infinite dilution in supercritical carbon dioxide. The retention factors were measured across temperatures ranging from 308.15 to 353.15 K and pressures of 8.20 to 31.03 MPa using supercritical fluid chromatography. The infinite dilution partial molar volumes were determined by taking the partial derivative of the retention factors with respect to the density of carbon dioxide. The obtained infinite dilution partial molar volumes range from −1.64 × 10−2 to 4.10 × 10−4 m3/mol, with large negative values observed near the critical point of carbon dioxide, indicating strong solvent–solute interactions. In this study, a new correlation model successfully predicts the experimental infinite dilution partial molar volumes with an average absolute relative deviation of 2.3 % over 86 data points.

Effect of waste travertine powder on properties of rhyolitic tuff-based geopolymer

This investigation explores the potential of geopolymer technology as an eco-friendly substitute for conventional construction materials by emphasizing the innovative use of naturally occurring green rhyolitic tuff and repurposed travertine powder in geopolymer paste formulations. Replacement levels of tuff with travertine at 40 %, 45 %, and 50 %, along with an alkaline solution with a NaOH molarity range of 8.2 M–22.1 M, have been analyzed for their impact on flowability, water absorption, porosity, compressive strength, and unit weight of the geopolymers over curing periods of 2, 28, and 90 days. The flowability measurements show that adding 40 %, 45 %, and 50 % travertine leads to approximately 7 %, 31 %, and 31 % reductions in the flowability of the geopolymer, respectively. It is demonstrated that adding 40 % travertine significantly improves the geopolymers’ compressive strength with an 11.5 M NaOH concentration, showing substantial increases of approximately 15.5, 9.0, and 2.4 times at the curing duration of 2, 28, and 90 days, respectively, relative to the geopolymer without travertine. As an optimum points, an 18.5 M NaOH and an 0.7 solution-to-powder ratio decrease the long-term apparent porosity and water absorption of the geopolymer without travertine by about 14 % and 19 % compared to those at the same solution-to-powder ratio with 11.5 M NaOH, respectively. Microscopic examinations were employed to validate the development of sodium aluminosilicate hydrate, calcium aluminosilicate hydrate, and calcium silicate hydrate gels, underscoring the advantageous contribution of the elevated CaO content in the travertine to the geopolymer matrix. This research not only highlights the environmental benefits of repurposing waste materials but also contributes to the development of more sustainable and durable geopolymer pastes, offering a promising approach to enhancing environmental stewardship in material science practices.

Stoichiometric Study on Ion Composition of a Precursor in Chemical Bottom-Up Synthesis for Peroxo-Titanate.

Layered alkali titanates of the lepidocrocite type are gaining enormous interest in various fields owing to their unique properties. These materials are mainly synthesized through a hydrothermal alkali treatment. However, this method uses a highly concentrated alkali solution, which has high environmental impacts and is therefore unsuitable for mass synthesis. Herein, we propose an efficient method for the large-scale synthesis of layered sodium titanate structures (Na2-x H x Ti2O5) using a recently reported bottom-up chemical process. The effects of the Na:Ti molar ratio in the peroxo-titanium complex ion precursor on the products are investigated through stoichiometric calculations for a molar ratio range of 10:1-1:1. The optimal ratio for the complete ionization of TiH2 (which is the starting material) to form the peroxo-titanium complex ion is found to be 1.1:1. The amount of alkali raw material required is 99.6% lower than that required in the traditional hydrothermal method. The crystal structures and morphologies of the samples are almost identical regardless of the Na:Ti molar ratio. The precursor-derived peroxo bonds narrow the energy band gaps of the layered titanates even when the amount of titanium ions dissolved in the precursor increases. The proposed method is not only an efficient synthetic route for mass production but also has potential applications in the development of photofunctional materials.

Comparative analysis of hydrogen-rich syngas production from various feedstocks using bubbling fluidized bed

Any carbon-based materials, including any trash that contains carbon, may be converted into sustainable energy through the thermochemical process known as gasification. The bubbling fluidized bed (BFB) is used for sewage sludge (SS), plastic waste (PW), and refuse-derived fuel (RDF) gasification. The sensitivity analysis of gasification processes is examined. The maximum H2 selectivity in RDF gasification is 70 %, followed by SS (65 %) and PW (62 %) at S/B=2. PW gasification, although producing more H2, generates more CO and CO2 than RDF and SS because to its high carbon content. At 700°C–800°C, three feedstocks have good H2 selectivity. RDF gasification has the best selectivity of all component products over the temperature range. The H2/CO molar ratio range (1–2) for chemical synthesis suggests steam to biomass (S/B) values of 1.2–2.6 for RDF and SS. As S/B value increases, CO/CO2 molar ratio increases, which compresses CO2 for CO production, improving syngas quality, notably for power generation. In PW gasification, the H2/CO ratio (≤2) is expected at >750°C. Pressure only effects H2/CO and CO/CO2, in PW gasification. The evaluation of lower heating value (LHV) and cold gas efficiency (CGE) involves exploring a range of selected parameters. Elevated reaction temperatures positively influence both LHV and CGE; however, this is not the case for S/B ratio and reaction pressure. Among the gasification processes, PW gasification exhibits the highest LHV, while SS gasification demonstrates the highest CGE. Besides, the gasification efficiency (ƞG) is found about 35–41 % at the S/B=2, which is lower than the efficiency in terms of CGE (57.6 %) due to the energy consumption increase as the temperature increased. O2/S increases negatively affect product composition but allow parameter indicator value adjustment to parameter indicator of the desired syngas product quality.

Experimental and theoretical studies on thermodynamic activities of binaries ferric and magnesium chlorides in aqueous solutions at various temperatures

The investigation of the thermodynamic properties of binary systems of ferric and magnesium chlorides in aqueous solutions was reported at various temperatures using both the hygrometric method and thermodynamic modeling. Water activities were measured over a molality range of 0.100 up to mmax(FeCl3)= 2.500 mol·kg−1 and to mmax(MgCl2)=(5.798, 6.090, 6.394, and 6.839) mol·kg−1at temperatures from 298.15 K to 353.15 K, respectively. From the new measurements, the osmotic coefficients of water were evaluated and compared with the existing literature data at ambient temperature. These coefficients were treated at various temperatures using established thermodynamic models of the Pitzer, Filippov–Charykov–Rumyantsev, extended ion interaction, and Clegg–Pitzer–Brimblecombe. The relevant properties of ferric and magnesium electrolyte solutions were determined in the temperature range. Indeed, the parameterizations of FeCl3(aq) and MgCl2(aq) were evaluated and employed for the computation of solute activity and osmotic coefficients. Based on literature emf data for MgCl2(aq) at a temperature of 298.15 K, the consistency of the activity coefficients was evaluated using an adequate model, and an excellent description of the prediction activity coefficients is obtained by the extended ion interaction model. Then, the recommended activity coefficients were given at various temperatures by extending this procedure. An experimental investigation was also carried out to evaluate the solubility equilibrium of MgCl2 in aqueous solutions at different temperatures. The solubility product and standard Gibbs energies of dissolution and formation were also calculated at different temperatures and compared with those existing in the literature.

Novel approaches to monitoring the formation of self-assembled colloids composed of cationic surfactants and alginate polysaccharide

In actual work, the self-assembly process of alginate (Alg) polysaccharide having low molecular weight (240 kDa) with cationic surfactants from the family of trimetylammonium bromide (TAB) derivatives was investigated at wide polysaccharide/surfactant molar ratio range through the interpretation of the formation of non-aggregated colloidal complexes.On one hand, the critical micelle concentration (cmc) values of the studied TAB surfactants having C12C18 chain length were determined and published for the first time in phosphate buffer solution. In addition to the applied conventional measurement procedures like tensiometry, light scattering, calorimetry, and equilibrium dialysis-based methods, the applicability of streaming potential technique was also demonstrated for the first time for these types of systems to gain a deeper insight into the formation process of the complexes built up by biocompatible polysaccharides and cationic surfactants. Through the interpretation of the change of the streaming potential values as a function of increasing surfactant's concentration it was clearly highlighted that both the individual and cooperative binding process of the surfactants can be clearly identified followed by the aggregation of the polysaccharide-surfactant colloidal complexes and the formation of surfactant micelles in the bulk dispersion.

Investigation of acoustical excess parameters and FTIR studies for binary liquid mixtures of tetrachloroethylene and cyclopentanone at different temperatures.

Abstract Speed of sound (U), Density (ρ), and viscosity (η) values of liquid mixtures of Tetrachloroethylene with Cyclopentanone and pure liquids were determined at regular intervals of molar range at different temperatures (303.15, 308.15, 313.15, 318.15) K. From the experimentally determined values, thermo-acoustic parameters such as excess molar volume (VE) and excess free length (Lf E), excess Gibb’s free energy (ΔGE) and excess enthalpy (HE) have been estimated. The variations of the above parameters discussed based on intermolecular interactions existing in this binary mixture. The computed values of sound speed in the mixture from various theories are compared with experimentally calculated values and have a clear check to validate the theories for the present system, and FTIR studies provide detailed analysis of molecular interactions.

FORMATION MECHANISM AND SYNTHESIS OF HIGHLY CRYSTALLINE POROUS ZnO SUPERSPHERES VIA SOL-GEL PROCESS: EVOLUTION FROM INTACT HOLLOW STRUCTURES TO POLLEN-LIKE MORPHOLOGIES

The synthesis of hollow and porous (HP) ZnO superspheres with intact hollow structures is crucial for various applications, yet it poses significant challenges. This article explores the fundamental aspects of preparing highly crystalline HP ZnO superspheres via a sol-gel process, elucidating the synthetic strategy, formation mechanism, and subsequent utilization for generating pollen-like ZnO superstructures. Under solvothermal conditions at 200°C, employing zinc acetate (0.065 M) in diethylene glycol with varying molar ratios of H2O/Zn, a range of ZnO particles and superspheres were synthesized. Within a molar ratio range of 2 - 4, initial nanoparticles self-assembled into solid and porous (SP) superspheres, evolving dominantly towards or along the c-axis, resulting in HP superspheres with intact hollow structures. Conversely, molar ratios of 6 - 20 yielded only separate nanocrystals instead of superspheres. The critical role of the H2O/Zn molar ratio in forming HP superstructures with intact hollows was highlighted, controlling Ostwald ripening and outward diffusion rates, with a molar ratio of 2 identified as a prerequisite for intact HP superspheres. The resultant intact HP superspheres exhibited intense and sharp band gap emission at 389 nm, indicating potential for optoelectronic applications. Furthermore, the study introduces pollen-like ZnO colloids derived from these intact HP ZnO superspheres, offering stable dispersion. Crystal growth predominantly occurred along the outward-oriented c-axis. The intact HP ZnO superspheres serve as a promising template system for biomimetic pollen-like ZnO superstructures.

Development of bentonite-based organo-geopolymer hybrid wood binder

The study addresses concerns associated with formaldehyde-based adhesives in wood panel board production by proposing geopolymer-based wood binders as promising, formaldehyde-free alternatives. Using bentonite, the research delves into the development and performance properties of this geopolymer wood binder. The BET method was employed for the surface characterization of precursor raw materials for binder preparation. Si and Al elements identified through XRF analysis were correlated with characteristic bands in the FTIR spectrum. Alkaline activation solutions, employing sodium silicate and sodium hydroxide with a molar ratio range of 0.5 to 2.5 (SiO2:Na2O), revealed that binders with a molar ratio of 2.5 exhibited lower pH and higher adhesion strength. Different geopolymer formulations at solution to powder ratios (s/p) of 1.33, 3, and 3.5 determined s/p 3.5 as optimal for bentonite-based organo-geopolymer binders. Viscosity, gel time, pH, and solids content were examined, showing the effectiveness of substituting 10% silica fume to enhance the geopolymerization process and improve adhesion. Modifications using citric acid, sucrose, paraffin, pMDI, triacetin, and resorcinol demonstrated wet bonding strength comparable to urea formaldehyde adhesive. Analytical techniques, including FTIR spectroscopy, XRD analysis, and SEM EDX analysis, provided insights into functional groups, crystallographic properties, and microstructural characteristics. The concentration of Si and Al compounds on the bonding line, coupled with Na element diffusion, was observed through these analyses. Light microscopy of lap shear samples revealed a thinner bonding line, affirming effective binder penetration into wood cell lumens in bentonite-based organo-geopolymer binder formulations.

The throughput capacity of the main gas pipeline when transporting gas-hydrogen mixtures

To determine the effect of hydrogen concentration in the gas-hydrogen mixture on the throughput capacity of the main gas pipeline and the volume of energy transported by it. The range of molar concentrations of hydrogen in the gas-hydrogen mixture up to and including 20%, which does not require significant technical modernisation of the system, was investigated.Performing theoretical studies and applying mathematical modelling methods to establish the regularities of thermo hydrodynamic processes in a gas pipeline, gas turbine and centrifugal blowers while transporting gas-hydrogen mixtures.In the example of a gas turbine unit widely used in the gas transmission system of Ukraine, it was found out that the molar content of hydrogen, if it does not exceed 20%, has a negligible effect on its rated power and other energy parameters. Adding hydrogen to natural gas with the above molar content will lead to a slight decrease in the pipeline system's capacity (up to 5%) and a significant reduction in the volume of energy transportation (up to 18%).The next stage of the study is to determine the impact of gas-hydrogen mixture properties on the pipeline capacity, taking into account changes in seasonal factors and the degree of system load.A method and software have been developed to predict the pipeline capacity and energy transfer volume for the transportation of gas-hydrogen mixtures, taking into account the influence of seasonal factors, gas-dynamic characteristics of blowers, and combinations of gas-pumping units at compressor stations.Modern international standards are used to calculate gas-hydrogen mixtures' physicochemical and thermodynamic properties under standard and operating conditions. The originality of the approach lies in the fact that the compressor station and the linear section of the gas pipeline are considered as a SLE gas-dynamic system.

Long period grating based molecularly imprinted fiber optic sensor for the label-free detection of bisphenol A

The molecularly imprinted fiber optic (MIFO) sensors are recognized for its reliability, sensitivity and selective analyte identification. In this study, we report a Long-Period Grating (LPG) based MIFO sensor developed for the label-free detection of Bisphenol A (BPA) in water samples. The sensor is fabricated by polymerizing hydrogel precursor containing BPA on the LPG, followed by etching BPA molecules. The rebinding of the BPA molecule to the molecularly imprinted long period grating Bisphenol A (MILPG-BPA) sensor causes the hydrogel to swell, leading to a peak shift in the LP07 resonant mode of the sensor. This shift is linear across BPA concentrations ranging from femto molar to nano molar range with a low limit of detection of 0.146 fM. The non-imprinted long period grating (NILPG) sensor showed no selective binding of the BPA molecule, underscoring the significance of the microenvironment established through molecular imprinting for effective sensing. The MILPG-BPA sensor exhibits high selectivity in detecting the BPA molecules among the potential interferents. Furthermore, it has a rapid response time and reusability, thus holding promise for a wide range of applications.

The cytotoxic effects of prazosin, chlorpromazine, and haloperidol on hepatocellular carcinoma and immortalized non-tumor liver cells.

Liver cancer annually accounts for over 800,000 cases and 700,000 deaths worldwide. Hepatocellular carcinoma is responsible for over 80% of liver cancer cases. Due to ineffective treatment options and limited surgical interventions, hepatocellular carcinoma is notoriously difficult to treat. Nonetheless, drugs utilized for other medical conditions, such as the antihypertensive medication prazosin, the neuroleptic medication chlorpromazine, and the neuroleptic medication haloperidol, have gained attention for their potential anti-cancer effects. Therefore, this study used these medications for investigating toxicity to hepatocellular carcinoma while testing the adverse effects on a noncancerous liver cell line model THLE-2. After treatment, an XTT cell viability assay, cell apoptosis assay, reactive oxygen species (ROS) assay, apoptotic proteome profile, and western blot were performed. We calculated IC50 values for chlorpromazine and prazosin to have a molar range of 35-65µM. Our main findings suggest the capability of both of these treatments to reduce cell viability and generate oxidative stress in HepG2 and THLE-2 cells (p value < 0.05). Haloperidol, however, failed to demonstrate any reduction in cell viability revealing no antitumor effect up to 100µM. Based on our findings, a mechanism of cell death was not able to be established due to lack of cleaved caspase-3 expression. Capable of bypassing many aspects of the lengthy, costly, and difficult cancer drug approval process, chlorpromazine and prazosin deserve further investigation for use in conjunction with traditional chemotherapeutics.

Optimization of magnetic properties of MnFe2O4 by modulating molarity of NaOH as precipitating agent

Abstract MnFe2O4 nanoparticles were synthesized using the co-precipitation method with a wide range of molar concentrations of sodium hydroxide 0.76 M−3.0 M. X-ray diffraction, field effect scanning electron microscopy, transmission electron microscopy, and vibrating sample magne-tometry were employed to characterise the structural, morphological, and magnetic characteristics of nanoparticles. Field effect scanning electron microscopy and transmission electron microscopy images show that the particles were spherical in shape for all the samples except for sample prepared at a molar concentration of 1.3 M. Particle shape was found to depend on the molar concentration of NaOH. The hysteresis loops of the samples possessed a very small area and low coercivity. The crystallite size (cs), saturation magnetisation, coercivity, retentivity, squareness ratio and anisotropy constant were found to be dependent on the molar concentration on NaOH. M S was noted to be at a maximum of 64.4 emu g−1 at a molar concentration of 1.3 M. The ratio t/cs (where t is the thickness of the dead layer) was calculated to account for the variation in M S. H C was found to be maximum of ∼52 Oe at molar concentrations between 1.0 M and 2.0 M. M r and M r/M S were found to be a maximum of 8.95 emu g−1 and 0.15, respectively, for the molar concentration of 2.0 M.

Carrageenan derived polyelectrolyte complexes material: An effective bifunctional for electrochemical sensing of sulfamethazine and antibacterial activity

Biopolymer-derived polyelectrolyte complexes (PECs) are a class of materials that have emerged as promising candidates for developing advanced electrochemical sensors due to their tunable properties, biocompatibility, cost-effective production, and high surface area. PECs are formed by combining positively and negatively charged polymers, resulting in a network with intriguing properties that can be tailored for specific sensing applications. The resultant PECs-based nanocomposites were used to modify the glassy carbon electrode (GCE) to detect the sulfamethazine (SFZ) antibiotic drug. In addition, electrochemical studies using electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV), and differential pulse voltammetry (DPV) are used to evaluate the SFZ detection ability. Similarly, various microscopic and spectroscopic studies investigated the nano composite's structural features and morphological behavior. The κ-CGN/P(Am-co-DMDAAc)-GO modified GCE demonstrated excellent detection ability of SFZ with the nano molar range and without interference with similar structural components. Furthermore, the newly fabricated electrode κ-CGN/P(Am-co-DMDAAc)-GO was derived from naturally available materials, water-soluble, low cost, biocompatible, exhibits good conductivity, and excellent catalytic properties. Finally, κ-CGN/P(Am-co-DMDAAc)-GO- modified GCE has versatile, practical applications for detecting SFZ in real-time samples and determining the efficacy of an antibacterial activity.

Chloramine Disinfection of Levofloxacin and Sulfaphenazole: Unraveling Novel Disinfection Byproducts and Elucidating Formation Mechanisms for an Enhanced Understanding of Water Treatment.

The unrestricted utilization of antibiotics poses a critical challenge to global public health and safety. Levofloxacin (LEV) and sulfaphenazole (SPN), widely employed broad-spectrum antimicrobials, are frequently detected at the terminal stage of water treatment, raising concerns regarding their potential conversion into detrimental disinfection byproducts (DBPs). However, current knowledge is deficient in identifying the potential DBPs and elucidating the precise transformation pathways and influencing factors during the chloramine disinfection process of these two antibiotics. This study conducts a comprehensive analysis of reaction pathways, encompassing piperazine ring opening/oxidation, Cl-substitution, OH-substitution, desulfurization, and S-N bond cleavage, during chloramine disinfection. Twelve new DBPs were identified in this study, exhibiting stability and persistence even after 24 h of disinfection. Additionally, an examination of DBP generation under varying disinfectant concentrations and pH values revealed peak levels at a molar ratio of 25 for LEV and SPN to chloramine, with LEV contributing 11.5% and SPN 23.8% to the relative abundance of DBPs. Remarkably, this research underscores a substantial increase in DBP formation within the molar ratio range of 1:1 to 1:10 compared to 1:10 to 1:25. Furthermore, a pronounced elevation in DBP generation was observed in the pH range of 7 to 8. These findings present critical insights into the impact of the disinfection process on these antibiotics, emphasizing the innovation and significance of this research in assessing associated health risks.

Isotope effects accompanying δ2 H, δ18 O and δ17 O analyses of aqueous saline solutions using cavity ring-down laser spectroscopy.

The presence of substantial amounts of dissolved salts creates serious difficulties in isotope analyses of water samples using conventional isotope ratio mass spectrometry. Although nowadays laser-based instruments are increasingly used for this purpose, a comprehensive assessment of isotope effects associated with direct analyses of aqueous saline solutions using this technology is lacking. Here we report the results of laboratory experiments aimed at quantifying isotope effects associated with direct, δ2 H, δ18 O and δ17 O analyses of single-salt solutions and double-salt mixtures prepared with a water of known isotopic composition. Three single-salt solutions (NaCl, CaCl2 and MgSO4 ) and two double-salt mixtures (NaCl + CaCl2 and NaCl + MgSO4 ) were prepared and investigated for a wide range of molalities. The triple-isotope composition of the prepared solutions was analysed with the aid of a Picarro L2140-i Cavity Ring-Down Spectroscopy analyser. The NaCl and CaCl2 solutions revealed small negative salt effects, independent of molality and comparable with measurement uncertainty. The MgCl2 solution showed the highest salt effects, reaching saturated solution ca. +2.7‰ (2 H), -3.5‰ (18 O) and -1.7‰ (17 O). Salt effects for the double-salt mixtures generally mirrored the effects observed for the single-salt solutions. The observed salt effects are discussed in the context of processes occurring during the injection of the salt solutions into the vaporizer unit of the CRDS analyser. The presented study has demonstrated feasibility of direct, triple-isotope analyses of aqueous salt solutions using a Picarro L2140-i CRDS analyser for a broad range of salinities up to saturated conditions. Large uncertainties of 17 O-excess determinations for solutions forming hydrated salts preclude the use of this parameter for interpretation purposes.

Synthesis of Cytotoxic Quino[4,3-b]carbazole Frameworks through an Intramolecular Diels-Alder Reaction.

An intramolecular Diels-Alder reaction of positionally isomeric indole-2/3-phenylvinyl-N-alkynylated (N-phenylsulfonyl)amines has been successfully exploited for the synthesis of quino[4,3-b]carbazole and its analogues. This reaction proceeds through a [4 + 2] cycloaddition followed by elimination and deprotection of phenylsulfonyl units to afford the quinocarbazoles in moderate to good yields. The reaction features a broad substrate scope and remarkable functional group forbearance. A preliminary in vitro cytotoxicity evaluation of representative quino[4,3-b]carbazoles was performed against NCI-H460 human cancer cell culture. Among the quino[4,3-b]carbazoles evaluated, five of the fluorine-containing quinocarbazoles displayed nano molar range (0.8-2.0 nm) GI50 values. The UV-vis and fluorescence spectral studies of representative quinocarbazoles were also performed. Like ellipticine, four of the quinocarbazoles displayed dual emissions confirming the existence of p-quinonoid like tautomeric forms in a polar protic solvent.