Water Medium Research Articles

Exopolysaccharides production by Lactobacillus fermentum under different growth conditions in coconut water medium

Background: Exopolysaccharides (EPS) production gain a lot of attention over recent decades, because EPS can provide beneficial effects, not only on the industrial application but also on the health sector. The understanding of the optimal condition for EPS production will increase the productivity of EPS and can develop EPS with desirable properties. The factors affected EPS production are additional of sugar concentration, temperature, fermentation time, and others. The current work aimed to optimize the utilization of a byproduct leftover of coconut water on the EPS production from Lactobacillus fermentum. Methods: The EPS synthesis were analyzed under various growth conditions in coconut water such as additional of sucrose concentration and incubation times. EPS production of Lactobacillus fermentum was performed by adding 1%, 2%, and 3% of sucrose and 12, 24, 36, and 48 h of incubation periods. The obtained data were analyzed statistically using a two-ways ANOVA test. Results: The EPS production increased as the sucrose concentration and incubation time were increased. The optimal production was found to be in the media supplemented with 3% sucrose and 48 h of incubation period, which gave 12.613 g/L of EPS production. Conclusions: Media of coconut water is suitable for EPS production by Lactobacillus fermentum. Under 3% of additional sucrose concentration and 48 h of incubation time, it produced a larger number of EPS compare to other conditions.

Influence of coal rock on tight sandstone reservoirs in coal seam roofs: A case study of the lower jurassic in the Taibei sag, Turpan-Hami Basin, China

After shale gas, coalbed methane and gas hydrate, coal measure gas has become an important new unconventional resource, for which exploration to depths of >3000 m are taking place in China. However, owing to unusual geological conditions and as yet inadequate exploration technology the current level of exploration is low. The acidic water medium in coal-bearing strata affects the diagenesis of adjacent tight sandstone reservoirs, thereby influencing reservoir quality. However, the current understanding of the impact mechanism of coal seams on neighboring tight reservoirs is insufficient, constraining the further exploration of coal measure gas. In order to reveal the influence of coal rock on a tight sandstone reservoir in its roof, we study the coal-bearing strata of the Xishanyao Formation in the Taibei Sag of the Turpan-Hami Basin using cast thin sections, physical property tests, XRD analysis, carbon and oxygen isotopes, high-pressure mercury intrusion and low-temperature N2 adsorption. The carbonate cement in the sandstone reservoir of the coal seam roof was formed by the decarboxylation of organic acid. The organic acid, containing CO2 generated by coal rock hydrocarbon generation, has modified the tight sandstone reservoir of the coal seam roof via dissolution. This has improved the physical properties and pore throat structure of the tight sandstone reservoir close to the coal-sandstone interface. The amount of improvement extends to about 2 m into the sandstone. During the upward transport of fluid, the pre-existing carbonate cement dissolves and then precipitates, which causes the CO2 generated by the organic acid decarboxylation to exchange carbon with the carbon isotopes in the pre-existing carbonate cement. Due to the slow upward diffusion rate and limited diffusion distance of the CO2-bearing fluids, the carbonate cement exhibits gradually heavier δ13CPDB values with increasing distance from the coal-sandstone interface.

Fabrication of CZS NRs/NiSx NPs hybrids with abundant S-vacancies for signally promoting photocatalytic hydrogen production

The cocatalysts play a key role in photocatalytic technology in remarkably improving the efficiency of H2 evolution. Herein, S vacancies-rich Cd0.6Zn0.4S nanorods (CZS NRs) were prepared via solvothermal method. Then, as-obtained CZS NRs were modified with Ni–Co PBA-derived NiSx nanoparticles (NPs) cocatalyst using grinding method. The optimized CZS/NiSx-N-1.5 hybrids (CZS/NiSx-N, where N represents nickel nitrate which was used as nickel source) exhibited outstanding stability and activity, the average rate of H2 was up to 192.82 mmolg−1h−1 in deionized water medium, which was 201.4% higher than that of CZS. Besides, NiSx-A and NiSx-C cocatalysts with different particle sizes were obtained using nickel acetate (A) and nickel chloride (C) as nickel source, respectively. The CZS/NiSx-C-1.5 and CZS/NiSx-A-1.5 exhibited the H2 evolution rate of 180.70 and 201.93 mmolg−1h−1 in deionized water medium, respectively. The as-prepared materials also exhibited the excellent H2 evolution performance in natural seawater medium. Besides, the photocatalytic mechanism of H2 evolution over CZS NRs/NiSs NPs was also discussed. This work develops a novel H2 evolution cocatalyst and unveils the relationship between the loading amount/particle size of cocatalyst on the H2 evolution rate.

Stainless steels as a solution for corrosion and erosion problems involving grains in agribusiness sector applications

Agricultural activities such as grain processing play a crucial role in Brazil's economy, contributing significantly to its gross domestic product (27.4% in 2021). The use of carbon steel equipment leads to considerable environmental and economic losses in agribusiness due to corrosion. This study explores the erosion-corrosion behavior of a dual-phase 11Cr and an 18Cr8Ni stainless steel (SS), compared to a mild (ASTM A36) and a high-strength carbon (AHSS) steel under conditions close to the agribusiness reality. The impact of corn particles as erosive component associated to pure water and chloride-containing environments was studied using a fog chamber, a topic until now unexplored in the literature. The methodology adopted is novel and explores the erosion-corrosion synergy in cumulative steps, aiming to shed light on the mechanisms of corrosion and wear that affect the materials in the agribusiness industry. The findings reveal that corn particles, despite their soft nature, can easily remove non-adherent corrosion products from the steel surface. In the deionized water medium, the impact of the soft particles can also shift the corrosion pattern of advanced high-strength steels from general corrosion to localized pitting damage reduzing the corrosion rates. The carbon and 11Cr steels showed the highest corrosion rates under the pure corrosion condition in both media. The erosion-corrosion process considerably reduced the corrosion rate, mainly in the deionized water medium for the carbon steels. An exception to this behavior was 18Cr8Ni steel, whose corrosion rates, however, were the lowest among the materials. Low-chromium stainless steel emerges as a cost-effective solution to erosion-corrosion challenges in the agribusiness segment.

Accurate internal cavities and kissing bond sizing in metal plates by using the time-of-flight of laser-induced ultrasound waves

This paper presents a nondestructive method for accurately identifying internal flaws in metal plates, which is crucial for ensuring structural integrity in safety-critical applications. The technique relies on analyzing laser-induced ultrasound (LIU) longitudinal wave time-of-flight, as demonstrated through a theoretical five-layer model. Experimental validation was conducted using a piezo-sensor in contact with a slab containing millimetric artificial cavities immersed in air, resulting in a discrepancy of 5.05%. In contrast, experiments performed in a water medium exhibited a lower discrepancy of 2.5%. (Discrepancy refers to differences between measurements obtained through an experimental time-of-flight analysis and caliper measurements.) The results obtained in water-based experiments affirm the accuracy of the proposed model. B-scan measurements and the five-layer model were utilized to generate 2D reconstructed images, enabling precise localization and sizing of cavities and kissing bonds between plates, finding an average size of kissing bond of 30 µm. In conclusion, the proposed five-layer model, based on a longitudinal wave time-of-flight analysis, provides a straightforward framework for an easy cavity and kissing bond measurements in metal plates.

Stabilization of a Photoradiated Naphthalene Diimide-Based Organic Radical Anion Inside a Peptide-Based Gel Matrix with an Improvement of Optoelectronic Properties.

An amino acid-conjugated naphthalene diimide (NDI)-based highly red fluorescent radical anion has been found in a water medium under the photoradiated condition. This molecule has failed to form the radical anion in the monomeric state; however, the J aggregation in the aqueous medium has ensured the formation of radical anion in the ambient condition after the irradiation of both sunlight and UV light exposure. Electron paramagnetic resonance (EPR) studies clearly suggest the formation of radical anions. Herein, the stability of the radical anion in the aqueous medium is only a few minutes as a small amount of shaking is enough to quench the radical anion in the solution state. Furthermore, the incorporation of this molecule into a peptide-based hydrogel matrix and the consequent photoirradiation have not only helped to develop radical anion in the gel matrix but also increased the enormous stability of the radical anion inside the hydrogel matrix even for 30 days. It is envisaged that the formation of the radical anion within the gel matrix prevents the free movement of the NDI molecules and restricts the diffusion of molecular oxygen in the system, which leads to the stability of the radical anions in the gel. Moreover, the stability of the radical anion within the gel has helped to enhance the conductivity of the hybrid gel to a great extent. Interestingly, the radical anion-containing hybrid hydrogel has shown a potential photoswitching property.

Isolation, Identification, and Biofloc Production: Potential of Floc-Forming Bacteria Using a Novel Monoculture Approach and Medium

Biofloc is one of the suitable alternatives for decreasing food costs and increasing the immunity of cultured organisms against pathogens and diseases. This research aims to isolate, identify, and screen bioflocculant bacterial candidates to optimize practices for enhanced water quality management. Twelve bacteria were obtained from incubated shrimp pond water. These bacteria were tested for their ability to produce biofloc using a newly developed combination of Biofloc Standard Mineral Water (BSMW) and Biofloc Standard Medium (BSM) in a laboratory setting, utilizing an Imhoff cone. A novel medium was used for the first time for identifying biofloc-producing bacteria. Strain KBF-103 exhibited rapid biofloc production within 24 hours, making it suitable for pond water application. Strain KBF-103 was identified using molecular via 16S rRNA sequencing and shows a close relation with the Bacillus cereus strain.

Synthesis of cobalt nanoparticles in aqueous solutions assisted by polymer/inorganic hybrid

Hydrophilic polymer/inorganic hybrids (PIH) containing silica nanoparticles and polyacrylamide chains proved to be effective matrices for the in situ synthesis of cobalt nanoparticles. PIH sample was synthesized by free-radical polymerization of acrylamide from the unmodified surface of SiO2 nanoparticles and characterized by elemental analysis, dynamic thermogravimetric analysis, static light scattering, potentiometric titration, viscometry and transmission electron microscopy (TEM). The processes of borohydride reduction of cobalt ions from the Co(NO3)2·6H2O solution to nanoparticles in water medium and aqueous solutions of PIH were studied as a function of the concentrations of metal salt and hybrid concentrations using UV-Vis spectroscopy and TEM. A special approach to characterize the kinetics and efficiency of CoNPs formation in water medium and hybrid solutions using UV-Vis spectroscopy was implemented. The kinetic parameters of the CoNPs formation process as well as the yield, size, and morphology of nanoparticles in hybrid solutions and water medium at various concentrations of metal salt and hybrid were determined. The growth of both concentrations of reagents had a positive effect on the rate of formation of metal nanoparticles and their yield, but in all cases, the reduction process developed much slower in hybrid solutions compared to pure water. The morphology of the CoNPs/PIH nanocomposites was mainly represented by separate swollen hybrid particles containing metal nanoparticles with dav~3 nm.

Investigating the possibility of using subcritical water for extracting polycyclic aromatic hydrocarbons from soils of the dry-steppe zone

In the course of the model experiment, extraction conditions of 16 priority PAHs in subcritical water medium were selected for soils of the chestnut-solonetz complex. For low molecular weight 2-ringed naphthalene and 3-ringed acenaphthene, acenaphthylene, anthracene, phenanthrene and fluorene, the optimal extraction conditions correspond to 10 minutes at a temperature of 200°C. For high molecular weight 4- and 5-ring benz(a)anthracene, fluoranthene, pyrene, chrysene, benz(b)fluoranthene, benz(k)fluoranthene, dibenz(a,h)anthracene, as well as the pollutant of the first hazard class - benz(a)pyrene, the optimal extraction time reached 20 minutes at a temperature of 250°C. For 6-ring benz(g,h,i)perylene and indeno(1,2,3-cd)pyrene, the optimum extraction time increased to 30 minutes and the temperature to 300°C. When comparing the methods of extraction of pollutants from soils, it is shown that the extraction methods can be placed in the following descending order by the value of the extraction coefficient of priority PAHs from the studied types of soils: ultrasonic extraction (1.05) > subcritical extraction (1.13) > saponification method (1.25). Using multivariate analysis of dispersion it is shown that the efficiency of subcritical aqueous extraction decreases with increasing number of benzene rings in the PAH molecule, as well as with increasing soil salinity in the following order: Gleyic Kastanozems < Endosalic Kastanozems < Kastanozems Sodic < Solonets.

Influence of the parameters of the aquatic environment on the functioning of wireless channels optical underwater communication in information and measurement systems

The main challenge in creating underwater Internet of Things (UIoT) applications is to select the appropriate type of communication system, which must take into account the unique conditions of the underwater environment and data transmission requirements. Unlike terrestrial systems, where RF channels are widely used, underwater conditions require other solutions, as radio waves are significantly attenuated in the water, severely limiting the transmission range. A specific and little-studied aspect of underwater communications is the use of Underwater Wireless Optical Communications (UWOC). This paper focuses on investigating the effect of the characteristics of the aquatic environment on UWOC performance. The purpose of the study was to identify the relationship between the parameters of the aquatic environment and the UWOC channel in the interest of predicting the effectiveness of its application as part of UIoT networks, to substantiate the feasibility and prospects of using underwater optical wireless communications as part of distributed information and measurement systems. The paper presents the results of research on the relationship between the parameters of the aquatic environment and the underwater optical wireless communication channel. The interrelation of optical characteristics of the aquatic environment with the indicators of efficiency and quality of underwater optical wireless communication: normalised power, communication range, bit error rate, in turn, affecting the accuracy and reliability of the information received by the Consumer at the output of the information-measuring system. The influence of water medium turbulence on the communication indicators is assessed. It is shown that changes in the salinity of the aquatic environment as one of the factors causing turbulence negatively affects the main indicators of underwater optical wireless communication. It is shown that the assessment of the feasibility of underwater optical wireless communication should be made on the basis of a detailed analysis of the parameters of the aquatic environment of the water area in which its implementation is planned. The obtained results confirm the possibility and perspectivity of using underwater optical wireless communication as a part of distributed information-measuring systems on underwater objects located in different types of water areas.

Modelling Turbulent Flows near Coastal Structures Using Various Turbulence Models

Introduction. The reduction in beach width due to erosion is a significant issue that can either be mitigated or exacerbated by coastal protection structures. Modelling breaking waves near the coast and around coastal structures can be used to determine their impact on the dynamics of the coastal zone. The objective of this study is to model and analyze the dynamics of turbulent structures around a single breakwater, obtained using two turbulence modelling schemes: RANS and LES.Materials and Methods. Turbulence induced by breaking waves was investigated. The modelling was based on bathymetric measurements conducted along the Azov Sea coast and a three-dimensional wave hydrodynamics model supplemented with various turbulence calculation configurations.Results. Modelling results of wave processes generating turbulent flows in the presence of coastal protection structures using different turbulence models were obtained. Results obtained based on Reynolds-averaged Navier-Stokes (RANS) equations are compared with the results of Large Eddy Simulation (LES) approach with Smagorinsky dynamic subgrid-scale model (DSM).Discussion and Conclusions. The results showed that wave heights simulated by LES were higher than those simulated by RANS in the front and leeward regions of the coastal protection structure and were lower in its upper part. Thus, according to LES, a greater amount of wave energy was preserved after passing over the breakwater. Velocity vectors of the water medium showed the formation of a vortex when LES was used, whereas no evidence of such turbulent vortices was detected in the case of RANS, confirming the better performance of LES for turbulence modelling in the coastal zone. According to the presented results, LES is the preferred tool for generating turbulence under incoming wave conditions in engineering practices.

Development of Nanosecond Discharge in an Inhomogeneous Electric Field in Water Medium

Development of Nanosecond Discharge in an Inhomogeneous Electric Field in Water Medium

Investigating antitumor therapeutic efficacy using magnetic hyperthermia of Fe3O4 nanoparticles

Four sets of Fe3O4 nanoparticles were synthesized using a one-pot hydrothermal method using ethylene glycol (EG) and water reaction mixture. The EG coated Fe3O4 nanoparticles were characterized using XRD (X-ray diffraction) and DLS (dynamic light scattering). The nanoparticles hydrodynamic sizes are in the range 60-100 nm and showed good dispersibility in water and cellular medium without any aggregation. The specific absorption rate (SAR) under an alternating magnetic field (AMF) was measured to evaluate the magneto hyperthermic effect of the nanoparticles under field amplitudes of 51.85, 43.87, 35.89, and 27.92 kA/m and field frequencies in the range 384.5-167.30 kHz. The nanoparticles synthesized using 30% EG showed the highest SAR value of 372.95 W/g, whereas the particles synthesized using 70% EG showed a SAR value of 217.12 W/g. SAR values show a linear dependency on the AC frequency whereas the field amplitude displayed a nonlinear effect on the SAR. Breast cancer cells (MDA) treated with the nanoparticles for 30 minutes under an AMF of frequency of 384.5 kHz and strength of 24.67 kA/m showed a 50% decrease in cell viability. The cellular viability further decreased to 25% after 24 h treatment under the AMF which is remarkable for the therapeutic application of the nanoparticles. The apoptotic cell death showed a dependency on the AMF frequency and strength combinations.

An insight into the role of experimental parameters in advanced oxidation process applied for pharmaceutical degradation.

The advanced oxidation process (AOP) is an efficient method to treat recalcitrance pollutants such as pharmaceutical compounds. The essential physicochemical factors in AOP experiments significantly influence the efficiency, speed, cost, and safety of byproducts of the treatment process. In this review, we collected recent articles that investigated the elimination of pharmaceutical compounds by various AOP systems in a water medium, and then we provide an overview of AOP systems, the formation mechanisms of active radicals or reactive oxygen species (ROS), and their detection methods. Then, we discussed the role of the main physicochemical parameters (pH, chemical interference, temperature, catalyst, pollutant concentration, and oxidant concentration) in a critical way. We gained insight into the most frequent scenarios for the proper and improper physicochemical parameters for the degradation of pharmaceutical compounds. Also, we mentioned the main factors that restrict the application of AOP systems in a commercial way. We demonstrated that a proper adjustment of AOP experimental parameters resulted in promoting the treatment performance, decreasing the treatment cost and the treatment operation time, increasing the safeness of the system products, and improving the reaction stoichiometric efficiency. The outcomes of this review will be beneficial for future AOP applicants to improve the pharmaceutical compound treatment by providing a deeper understanding of the role of the parameters. In addition, the proper application of physicochemical parameters in AOP systems acts to track the sustainable development goals (SDGs).

Optimization Study of Water Interval Charge Structure Based on the Evaluation of Rock Damage Effect in Smooth Blasting

In tunnel smooth blasting, optimizing the water interval charging structure of peripheral holes is of great significance in improving the effect of smooth blasting and reducing the unit consumption of explosives. Addressing the issue of a single traditional evaluation standard, this paper proposes a composite index evaluation method for rock blasting damage in different zones, and the best charging structure is optimized according to the evaluation results. Taking Liyue Road Tunnel Light Smooth Blasting Project in Chongqing as the Research Background, the numeric models were established with ten kinds of charge structures, the charge structures and explosive quantity were optimized according to the evaluation results, and then the field tests were conducted. The results show that when the length of the water medium at the bottom of the hole is 20 cm, the damage range of the retained rock mass can be controlled while ensuring rock fragmentation. If the length of the water medium at the orifice and in the center of the hole is more than 30 cm, it will affect the superposition effect of the blast stress wave, resulting in under-excavation; in the preferred charge structure, the ratio of the length of the upper and lower explosives reaches 1:3, and the ratio of the length of the water medium is 2:2:1, which achieves a better rock-breaking effect in the field test.

Tenacious copper nanoclusters shielded by aromatic thiol for use in antibacterial, bioimaging, and dye degradation applications

Aromatic thiol-protected copper nanoclusters (CuNCs) have emerged as promising catalysts for dye degradation due to their unique optical and catalytic properties. In this study, we effectively synthesized CuNCs less than 10 nm-sized, very stable particles. The absorption peaks confirms that metal-to-ligand charge transfer, which favors the binding interaction of the frontier molecular orbitals and shifts the absorption bands of the free ligand and the extremely small water-soluble CuNCs in a blue direction in a water medium. Studies using electron microscopy support the existence of the pure form of the crystal-like shape. HRTEM confirms the morphology and less than 10 nm, and SAED and XRD confirm the crystallinity. This study on CuNCs for methylene blue sensing was conducted here. The detection range for methylene blue rapid degradation was observed. For the antibacterial studies when compared to gram-negative (E.coli), the synthesized copper nanoclusters had a high contact, as shown by a maximum value of zone diameter of 20 mm at a fixed concentration of 100 µg. The resulted in tunable quantum yields of 6.8 % which helped enhance the MCF-7 cancer cell line bioimaging, with the cancer cell line a maximum of 93.39 % cell viability with a minimum concentration of CuNCs 10 nM.

Water desalination system via ion immobilization on iron corrosion-based colloids and filtration by kevlar support

An efficient, scalable water desalination line has been introduced based on ion immobilization on the corrosion-based colloids (Diameter: from 10 nm to 20 µm) and filtration by a kevlar support. These particles are generated based on the galvanic cell behavior of some semi-galvanized wiring bundles inside a water medium according to the electrochemical cell schematic: Fe|Fe2+, OH-, H2|H2O with ΔG° of −73.0 KJ mol−1. To have an efficient desalination process, the contributions of different mechanisms such as mixed salt crystals, co-precipitation, and /or formation of various ionic charged species are present. These interactions resulted in the formation of micro/nano colloids (suspensions) with Fe2+ with other cations and anions, randomly, inside the bulk water medium. These particles are sandwiched among the arrays of the kevlar slices (5.0 × 5.0 cm) and play the role of the filter medium. In the introduced water desalination process, the population of the iron-based suspensions is controlled via a descending setting of the mass percentage of the semi-galvanic iron bundling wires along the water desalination line to control the number (population) of iron-based particles. This phenomenon consequently approves the condition for the efficient water desalination process at a laminar mass transfer condition with Reynolds number < 2000. The important factors of the removal efficiency are optimized using a multivariate optimization method based on a controllable waste purification efficiency threshold. This system possesses adequate advantages such as high water desalination efficiency, an acceptable water purification rate (3.0 L h−1, for only one water desalination line), low cost, enough simplicity, no residual water, and no need for any external driving source(s).

Adsorption of methotrexate on hyaluronic acid: A comparative DFT and molecular dynamics simulation insights

The potential of hyaluronic acid (HA) as a carrier for methotrexate (MTX) has been explored by quantum mechanics calculations in gaseous and water phases by density functional theory (DFT) and an all-atom molecular dynamics (MD) simulation in an explicit aqueous solvent. MTX adsorption on HA was systematically computed to analyze the bond formation, charge transfer, and binding energies between them in both gaseous and aqueous phases. The DFT analysis revealed polar covalent and electrostatic interactions between HA and MTX in both the gas and water mediums. In addition, according to calculations using natural bond orbitals (NBO), there is a shift of charges from σ and n orbitals in carbon, nitrogen, hydrogen, and oxygen atoms of MTX to n* and σ orbitals in oxygen and hydrogen atoms of HA, with appreciable charge-transfer energies in both the gas and water phases. Due to the solvent effects, the binding energy of the most stable HA-MTX complex was lower in the aqueous phase compared to the gas phase. Subsequently, a MD simulation in the water phase was performed to assess the stability of the complex derived from DFT calculations. The simulation validated the stability of the HA-MTX complex and revealed that MTX is most likely adsorbed onto the top edge of HA via a physical adsorption mechanism. These results indicate that HA may be a viable and efficient carrier for MTX in therapeutic applications.

Borophene Quantum Dots as Novel Peroxidase-Mimicking Nanozyme: A Dual-Mode Assay for the Detection of Oxytetracycline and Tetracycline Antibiotics.

The greater advantages and wide applications of zero-dimensional nanodots inspire researchers to develop new materials. Therefore, novel borophene quantum dots (QDs) were prepared by a hydrothermal liquid exfoliation technique using water medium. The borophene QDs proved to be highly stable in water medium for more than 120 days. The synthesized borophene QDs revealed intrinsic peroxidase mimetic activity using two chromogenic substrates, 3,3',5,5'-tetramethylbenzidine (TMB) and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid)diammonium salt (ABTS). The excellent intrinsic peroxidase activity toward TMB and ABTS substrates was executed using optimal reaction conditions (pH, borophene QDs' concentration, incubation time, and temperature). The formation of hydroxyl radicals in the presence of H2O2 upon TMB and ABTS oxidation played a significant role in the peroxidase reaction. The borophene QDs further proved to be successful for the colorimetric detection of antibiotics (oxytetracycline and tetracycline) using both TMB and ABTS peroxidase substrates. The limit of detection (LOD) for oxytetracycline and tetracycline was found to be 1.10 and 1.02 μM using TMB and 1.03 and 1.02 μM using ABTS chromogenic substrates, respectively. In addition, the fluorescence sensing of oxytetracycline and tetracycline over borophene QDs was also examined. The high fluorescence of borophene QDs (turn ON) was quenched (turn OFF) by oxytetracycline and tetracycline through the inner filter effect mechanism. The LOD of the fluorescence sensing of oxytetracycline and tetracycline was 1.14 and 1.08 μM, respectively. Interestingly, the borophene QDs could be used for the sensitive and selective colorimetric and fluorometric sensing of oxytetracycline and tetracycline after 120 days of storage. The synthesized borophene QDs with long-term stability and real sample analysis provide new insight as nanozymes with higher peroxidase mimetic and fluorescence performance and can be further exploited for medical diagnosis and environmental toxicants' detection.

Analysis on Vertical Variation Characteristics of Eogene Formation Water in Jizhong Depression

Jizhong Depression is located in the middle and west of Bohai Basin. During the Tertiary period, the depression was in a relatively stable state, and the shape of the depression did not change much, but the internal ups and downs of the depression were still continuous. In the Tertiary period, it experienced three development stages: early division, middle communication and late contraction, and three different sedimentary facies appeared accordingly. At the same time, it also caused three shifts of sedimentary centers. In the medium-term communication stage, two large water invasion periods occurred, and in some areas, the sedimentary water medium changed from salty to light twice. Oil and gas in the depression are associated with formation water, and the formation history of formation water is closely related to the formation history of oil and gas reservoirs. They are both in a hydrodynamic system and exchange material components for a long time. The lower tertiary is the main oil-bearing interval in central Hebei, but it is affected by the late tectonic movement and its structural characteristics are complex. Therefore, the hydrochemistry and vertical distribution characteristics of tertiary strata are studied. By effectively studying the distribution characteristics of formation water, it is concluded that the salinity of formation water in the basin tends to increase from edge to center and from shallow to deep, mainly in alternate blocking zones and alternate stagnation zones. The water deposition environment is relatively stable and the general regularity is obvious, which is an effective means to study the migration and distribution of oil and gas.