Liquid Reagents Research Articles

Mechanosynthesis of Enaminones and Mechanochemical Telescopic Synthesis of β,γ‐Unsaturated Butyrolactams

The stereoselective mechanochemical synthesis of Z‐enaminones and bis‐enaminones was achieved without any solid component in most cases, reacting 1,3‐dicarbonyl compounds with aliphatic/aromatic primary/secondary amines, which demonstrates the viability of reacting exclusively liquid reagents. The scale‐up was robust, from five to fifty and five hundred mmol without reduction in the reaction yield. The mechanochemical telescopic synthesis of β,γ‐unsaturated butyrolactams was achieved by formal [3+2] azaanulation reaction of intermediate enaminone with maleic anhydride, boosting the access of this potentially bioactive class of compound. The mechanochemical approach revealed its sustainable face in both syntheses, avoiding solid grinding auxiliary and purification by column chromatography. A symbol was suggested to differentiate the representation of the planetary ball mill from other mechanochemical reactors, wherein three spheres are surrounded by two curved arrows representing the two inherent movements of planetary trajectories of the reaction vessel of this equipment.

Microsphere integrated convective amplification sensor for all-in-one-pot detection of Mycoplasma pneumoniae

The integration of isothermal amplification with CRISPR-Cas systems play a crucial role in the point-of-care test of infectious pathogens, owing to their specificity, sensitivity, and portability. However, these systems lack rigorous internal amplification control for monitoring false negatives and rely on carefully designed guide sequences, which barriers to their further promotion and application. Additionally, the complexity of sample purification and the laborious preparation of liquid reagents significantly limit these systems to ready-to-use and direct sample-to-answer detection in on-site diagnosis. Here, we combined ready-to-use lyophilized microsphere, thermal lysis of pathogens, guide-sequence-independent convective amplification, internal amplification control for monitoring negative false and a portable multi-channel instrument to develop a microsphere integrated convective amplification sensor (MICASOR) system for on-site detection. MICASOR integrated the overall workflow of DNA testing into one-pot to achieve all-in-one-pot detection for on-site diagnosis. MICASOR is a rapid, potable, ready-to-use and guide-sequence-independent platform and can monitor false negatives. MICASOR can detect as low as 1 copy/μL of clinical samples of Mycoplasma pneumoniae within 15 minutes. Validated by 30 real clinical samples, MICASOR showed 100 % agreement with gold standard real-time PCR. These results suggest that MICASOR has great potential to promote the control of infectious diseases in the outpatients, communities and poor resource areas.

A-088 Clinically Significant Errors Using the Diazyme Total Bile Acid Assay on the Roche c502 Analyzer: Investigating a Result Error Identifies a Novel Large-Scale Testing Error Caused by Reagent Carryover

Abstract Background Thoroughly investigating single patient result errors may identify systemic, large-scale testing errors. The laboratory observed an event where a revision to a Total Bile Acid (TBA, Diazyme Laboratories, Inc.) patient result following a 22S quality control (QC) failure displayed a larger than expected difference (52 to 5mcmol/L). TBA is primarily used for diagnosis and monitoring of intrahepatic cholestasis of pregnancy with results >10mcmol/L considered elevated. Retrospective review of result revisions following QC failures (3/15/2017-5/30/2023) revealed that 50%(20/40) yielded result differences of >10mcmol/L(>20SD based on assay imprecision). The aim of this study was to apply a systematic approach to i) estimate the rate of TBA errors, ii) ensure accurate result reporting during investigation period, iii) perform root cause analysis (RCA), and iv) determine corrective and preventative action(s). Methods Residual samples from TBA testing (6/24-7/5/2023) were retested(n=158), differences >+/-3.0mcmol/L or 15% were confirmed on an alternate analyzer, and reports were revised. Automated repeat testing of TBA samples >10mcmol/L was operationalized 7/6/2023. Initial and repeat TBA results were compared(n=448) and results differing by >+/-20% were remeasured on an alternate analyzer. RCA was conducted using a fishbone diagram. NaOH reagent probe washes were implemented for TBA and the error rate was re-assessed. Assays run prior to TBA samples with errors (n=15) were identified. To assess reagent carryover a residual serum pool (TBA ∼5mcmol/L) was aliquoted into 5 tubes in a sample rack. The first sample in the rack was programmed to run an assay suspected of causing carryover followed by 4 TBA measurements. Mean±standard deviation(SD) TBA concentrations were calculated. TBA was also measured in the liquid reagent for amylase, lipase, acetylcholinesterase (ACE) and fructosamine. Results Initial TBA retesting yielded no errors when initial TBA was ≤10mcmol/L(n=51). For samples with TBA >10mcmol/L(n=107), 9(8.4%) had differences exceeding criteria with 8/9 being revised to ≤10mcmol/L. Analysis of automated patient repeat data showed a 3.8%(17/448) error rate when initial TBA >10mcmol/L. After NaOH reagent probe washes were implemented, the error rate decreased to 0.7%(3/448). Assays run directly before an erroneously high TBA result included: lactate, fructosamine, soluble transferrin receptor(STFR), lipase, and ACE. A serum TBA pool(mean±SD=5.1±0.4 mcmol/L,n=15) measured 37.6±1.2mcmol/L(n=3) and 6.7±0.7mcmol/L(n=3) after lipase and fructosamine, respectively. No other assays demonstrated carryover. TBA in lipase reagent compartment B and C was 653 and 649mcmol/L, respectively, and 653mcmol/L in fructosamine reagent compartment B. Conclusions A single patient TBA result revision was investigated and led to identification of reagent carryover causing erroneously high TBA results on the Roche c502 analyzer. Automatic, real-time, repeat testing was implemented to prevent reporting incorrect patient results until RCA could identify the cause. Occurrence rate of erroneous high TBA results decreased from 3.8% to 0.7% after implementation of NaOH washes on the instruments. Carryover experiments confirmed that lipase and fructosamine assays cause carryover when run prior to a TBA sample due to measurable TBA in the reagent. The lab is pursuing moving the fructosamine and lipase reagent to the Roche Cobas c701 to prevent the issue.

Human blood group type detection prototype focusing on agglutinin using microcontroller based photodiode

Blood is a fluid in the body that mainly serves as a medium for transporting various substances in the body. Detection of human blood group types with this microcontroller utilizes dark and light properties. The dark character appears due to agglomeration, while the light nature arises because of no agglomeration, for this to happen, a liquid reagent is needed. Administration of this liquid uses the aviator's breathing oxygen (ABO) system, which consists of reagent a, reagent b, and reagent c and mixing it with blood on the test paper. The number of blood samples in each reagent is based on blood lancet. Furthermore, the sensors used to detect these properties are photodiode and light emitting diode (LED) each of 3 pieces. The Arduino Uno is used to process sensor input while at the same time producing displayed human blood group type on the display screen. The test is carried out involving 12 blood samples and a medical officer. Medical officer are tasked reading directly the results of mixing between reagents and blood samples, after that are compared with the system. The results show that the deviation of the system reading is 0.167 for the sensor reading distance with the sample as far as 0.5 cm.

Embedded-deep-learning-based sample-to-answer device for on-site malaria diagnosis.

Improvements in digital microscopy are critical for the development of a malaria diagnosis method that is accurate at the cellular level and exhibits satisfactory clinical performance. Digital microscopy can be enhanced by improving deep learning algorithms and achieving consistent staining results. In this study, a novel miLab™ device incorporating the solid hydrogel staining method was proposed for consistent blood film preparation, eliminating the use of complex equipment and liquid reagent maintenance. The miLab™ ensures consistent, high-quality, and reproducible blood films across various hematocrits by leveraging deformable staining patches. Embedded-deep-learning-enabled miLab™ was utilized to detect and classify malarial parasites from autofocused images of stained blood cells using an internal optical system. The results of this method were consistent with manual microscopy images. This method not only minimizes human error but also facilitates remote assistance and review by experts through digital image transmission. This method can set a new paradigm for on-site malaria diagnosis. The miLab™ algorithm for malaria detection achieved a total accuracy of 98.86% for infected red blood cell (RBC) classification. Clinical validation performed in Malawi demonstrated an overall percent agreement of 92.21%. Based on these results, miLab™ can become a reliable and efficient tool for decentralized malaria diagnosis.

Development of Dry and Liquid Duplex Reagent Mix-Based Polymerase Chain Reaction Assays as Novel Tools for the Rapid and Easy Quantification of Bovine Leukemia Virus (BLV) Proviral Loads.

Bovine leukemia virus (BLV) is prevalent worldwide, causing serious problems in the cattle industry. The BLV proviral load (PVL) is a useful index for estimating disease progression and transmission risk. We previously developed a quantitative real-time PCR (qPCR) assay to measure the PVL using the coordination of common motif (CoCoMo) degenerate primers. Here, we constructed a novel duplex BLV-CoCoMo qPCR assay that can amplify two genes simultaneously using a FAM-labeled MGB probe for the BLV LTR gene and a VIC-labeled MGB probe for the BoLA-DRA gene. This liquid duplex assay maintained its original sensitivity and reproducibility in field samples. Furthermore, we developed a dry duplex assay composed of PCR reagents necessary for the optimized liquid duplex assay. We observed a strong positive correlation between the PVLs measured using the dry and liquid duplex assays. Validation analyses showed that the sensitivity of the dry duplex assay was slightly lower than that of the other methods for the detection of a BLV molecular clone, but it showed similar sensitivity to the singleplex assay and slightly higher sensitivity than the liquid duplex assay for the PVL quantification of 82 field samples. Thus, our liquid and dry duplex assays are useful for measuring the BLV PVL in field samples, similar to the original singleplex assay.

Improvement of X-ray Photoelectric Conversion Performance of MAPbI3 Perovskite Crystals by Ionic Liquid Treatment

Although perovskite has great potential in optoelectronic devices, the simultaneous satisfaction of material stability and high performance is still an issue that needs to be solved. Most perovskite optoelectronic devices use quantum dot spin coating or the gas-phase growth of perovskite thin films as the photoelectric conversion layer. Due to stability limitations, these materials often experience a significant decrease in photoelectric conversion efficiency when encountering liquid reagents. The self-assembled growth of hybrid perovskite crystals determines superior lattice ordering and stability. There are three types of ionic liquids—[Emim]BF4, EMIMNTF2, and HMITFSI—that can effectively enhance the X-ray photoelectric conversion performance of hybrid perovskite crystal CH3NH3PbI3 (MAPbI3), and the enhancement in the photocurrent leads to an improvement in the sensitivity of X-ray detectors. We soak the perovskite crystals in an ionic liquid and perform two treatment methods: electrification and dilution with ETOH solution. It is interesting to find that MAPbI3 perovskite single crystal materials choose the same optimized ionic liquid species in X-ray detection and photovoltaic power generation applications, and the effect is quite the opposite. Compared with untreated MAPbI3 crystals, the average photocurrent density of Electrify-HMITFSI MAPbI3 increased by 826.85% under X-ray excitation and the sensitivity of X-ray detectors made from these treated MAPbI3 crystals significantly increased by 72.6%, but the intensity of the PL spectrum decreased to 90% of the untreated intensity.

Achieving unprecedented stability in lyophilized recombinase polymerase amplification with thermostable pyruvate kinase from Thermotoga maritima

Recombinase polymerase amplification (RPA) is an isothermal DNA amplification reaction at around 41°C using recombinase (Rec), single-stranded DNA-binding protein (SSB), strand-displacing DNA polymerase (Pol), and an ATP-regenerating enzyme. Considering the onsite use of RPA reagents, lyophilized RPA reagents with long storage stability are highly desired. In this study, as one of the approaches to solve this problem, we attempted to use a thermostable pyruvate kinase (PK). PK gene was isolated from a thermophilic bacterium Thermotoga maritima (Tma-PK). Tma-PK was expressed in Escherichia coli and purified from the cells. Tma-PK exhibited higher thermostability than human PK. The purified Tma-PK preparation was applied to RPA as an ATP-regenerating enzyme. Liquid RPA reagent with Tma-PK exhibited the same performance as that with human PK. Lyophilized RPA reagent with Tma-PK exhibited higher performance than that with human PK. Combined with our previous results of RPA reagents of thermostable Pol from a thermophilic bacterium, Aeribacillus pallidus, the results in this study suggest that thermostable enzymes are preferable to mesophilic ones as a component in lyophilized RPA reagents.

Basophil activation in insect venom allergy: comparison of an established test using liquid reagents with a test using 5-color tubes with dried antibody reagents

BackgroundFlow cytometry-based basophil activation tests (BAT) have been performed with various modifications, differing in the use of distinct identification and activation markers. Established tests use liquid reagents while a new development involves the use of tubes with dried antibody reagents. The aim of this pilot study was to compare these two techniques in patients with insect venom allergy.MethodsSeventeen patients with an insect venom allergy were included in the study. The established “BAT 1” utilizes conventional antibody solutions of anti-CCR3 for basophil identification and anti-CD63 to assess basophil activation, whereas “BAT 2” uses dried anti-CD45, anti-CD3, anti-CRTH2, anti-203c and anti-CD63 for identification and activation measurement of basophils. Negative and positive controls as well as incubations with honey bee venom and yellow jacket venom at three concentrations were performed.ResultsSeven patients had to be excluded due to low basophil counts, high values in negative controls or negative positive controls. For the remaining 10 patients the overall mean (± SD) difference in activated basophils between the two tests was 0.2 (± 12.2) %P. In a Bland-Altman plot, the limit of agreement (LoA) ranged from 24.0 to -23.7. In the qualitative evaluation (value below/above cut-off) Cohen’s kappa was 0.77 indicating substantial agreement. BAT 2 took longer to perform than BAT 1 and was more expensive.ConclusionThe BAT 2 technique represents an interesting innovation, however, it was found to be less suitable compared to an established BAT for the routine diagnosis of insect venom allergies.

Drip Detection System based on STM32 Microcontroller

This design of the drip detection system is based on the STM32 microcontroller, making it highly practical and innovative. The system combines multiple sensors and control modules to achieve high-precision detection and monitoring of intravenous drip infusions. By integrating various sensors such as a drip rate detection module, a temperature sensor, and a water level detection module, the system can comprehensively monitor the status of the intravenous drip, including drip rate, liquid level, and temperature. Through data processing and control by the STM32 microcontroller, the system can real-time monitor the drip rate, liquid level, and temperature of the intravenous drip, and display these data on an OLED screen, providing intuitive information feedback. After conducting tests and analysis on the system, its stability and reliability have been verified. With its high-precision drip detection capability, the system can meet the needs of life science experiments for droplet detection. This system is widely applicable in various fields such as medical, chemistry, and biology. In the medical field, it can be used for precise drug delivery, thereby improving treatment effectiveness. In chemical and biological experiments, it can be used for accurate dispensing of liquid reagents, ensuring the accuracy of experimental results. The system features an OLED display, providing a user-friendly interface, and also comes with button operations, enabling users to conveniently set and operate system parameters. Overall, this drip detection system based on the STM32 microcontroller not only possesses a high level of technological sophistication but also has broad prospects for practical applications. It provides an efficient and accurate solution for droplet detection and will play a significant role in related fields.

3D Printed Micro-Nano Waveguide Ultrashort Bragg Grating on Optical Fiber Tip as a Contact Liquid Reagent Temperature Sensor

3D Printed Micro-Nano Waveguide Ultrashort Bragg Grating on Optical Fiber Tip as a Contact Liquid Reagent Temperature Sensor

Abstract 330: FusionPlex™-HT and VariantPlex™-HT: Automation ready solutions for anchored multiplex PCR

Abstract Introduction: Anchored Multiplex PCR (AMP™) assays, VariantPlex and FusionPlex are amplicon-based, next generation sequencing (NGS) workflows that identify genomic variations present in DNA or RNA input, respectively. AMP reagents are available in a lyophilized format which are user-friendly and convenient to store. However, lyophilized reagents are not suitable for liquid handlers or high-throughput environments. Thus, we developed AMP reagents in liquid format to satisfy the need for a platform-agnostic method of high-throughput (-HT) AMP library preparation. Methods: The performance of our liquid reagent-based VariantPlex-HT and FusionPlex-HT workflows were evaluated relative to legacy lyophilized reagents using several input of varying quantity, quality and type. In addition, we examined liquid reagent performance across multiple AMP panels, which target solid tumor and blood cancers variants. Prepared libraries were then sequenced and analyzed using Archer™ Analysis v7.0 software. Results: When using 50ng SeraSeq® Myeloid DNA input (LGC Clinical Diagnostics, Inc.) and the VariantPlex Core Myeloid panel (37 gene targets), both the lyophilized VariantPlex and VariantPlex-HT detected 100% (22/22) known variants ranging from 3.8% to 20.4% allele frequency (AF). When using low-quality FFPE and the VariantPlex Complete Solid Tumor panel (430 gene targets), both workflows captured 28/28 (AF: 1.4%-20.2%) and 11/11 (AF:1.2%-18.9%) single nucleotide variants (SNVs) and Insertion and Deletions (InDels) when 50ng of SeraSeq compromised FFPE or 200ng Horizon Severe FFPE was used as input, respectively. The FusionPlex-HT workflow consistently showed increased library complexity using the FusionPlex Lung V2 panel with 20ng or 50ng of Seraseq RNA Fusion Mix v4 input. This, coupled with greater on-target percentage resulted in an average increase in fusion supporting reads of 1.95x ± 0.53 and 2.2x ± 0.41 for 20ng and 50ng input, respectively. Next, we prepared a dilution series of SeraSeq RNA Fusion Mix v4 FFPE material at 100%, 25%, 10% and 5% dilutions. We utilized our FusionPlex Pan Solid Tumor panel (137 gene targets) which covers all expected fusions in this input material. At 100% and 25% dilutions, all expected fusions were detected by lyophilized FusionPlex and FusionPlex-HT workflows. However, at 10% and 5% dilutions FusionPlex-HT detected 100% and 91% of expected fusions, respectively, while legacy lyophilized reagents detected 80% and 60% of expected fusions. Citation Format: David Knupp, Christine Troutman, Allison Hadjis, Dhruti Legare, Paula Kalavakur, Michael Washburn. FusionPlex™-HT and VariantPlex™-HT: Automation ready solutions for anchored multiplex PCR [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 330.

STUDY OF THE PROPERTIES OF OILED FINE-DISPERSED OIL FROM THE VILALS OF THE METALLURGICAL PLANT

The task of obtaining of iron-containing secondary raw materials from finely dispersed oily slag accumulated in the dumps of metallurgical plants of Ukraine is important and urgent. This slag contains from 60 % to 75 % of iron oxides. Every year, up to 2.5 million tons of it is dumped into the dumps of PJSC “Kryvorizhstal” alone. To determine the favorable conditions for degreasing and cleaning of dump slag, studies of its structure, composition, physicochemical and technological properties were conducted. It is shown that, in addition to iron oxides, oil and water, there is a significant amount of more than 30 % of the amount of organic matter. The relative amount of components is different. A liquid reagent for the separation of organics from the starting material is defined. When the slag cleaned of organic matter is heated to 500 °C, a gradual decrease in the mass of the sample occurs, until it stops with exposure, with the preservation of all original iron oxides, FeO, Fe3O4 and Fe2O3, in the final product, in the absence of oil. When the slag is further heated to 950 °C, up to 97.5 % of hematite, Fe2O3, was obtained as the final product. In addition to hematite, oxides of other metals and more than 1.3 % of quartz are present in the final product in small quantities, up to 1.2 %. Bibl. 12, Fig. 8, Tab. 1.

Fast and on-site animal species identification in processed meat via centrifugal microfluidics and isothermal amplification.

We present a novel centrifugal microfluidic approach to rapidly identify animal species in meat products. The workflow requires a centrifugal cartridge for DNA extraction and for preparation of a recombinant polymerase amplification (RPA) reaction, a programmable centrifuge for processing the cartridge and an isothermal reader to perform the RPA. Liquid reagents are pre-stored on the cartridge and the meat sample can be added directly without any pre-treatment. With this system, we are able to identify six different animal species in a single run within one hour. In pork salami containing horse, turkey, sheep, chicken and beef meat, it was possible to identify species levels as low as 0.01%. In beef salami and cooked pork sausages 0.1% of foreign meat could be detected. This novel workflow enables rapid and sensitive species identification in processed meat at the point of need.

Liquid reagents are not enough for liquid assisted grinding in the synthesis of [(AgBr)(n-pica)]n.

This study investigates the mechanochemical reactions between AgBr 3-picolylamine and 4-picolylamine. The use of different stoichiometry ratios of the reagents allows [(AgBr)(n-pica)]n and [(AgBr)2(n-pica)]n to be obtained, and we report the new structures of [(AgBr)2(3-pica)]n and [(AgBr)2(4-pica)]n which are characterized by the presence of the following: (a) infinite inorganic chains, (b) silver atom coordinated only by bromide atoms and (c) argentophilic interactions. Furthermore, we studied the interconversion of [(AgBr)(n-pica)]n/[(AgBr)2(n-pica)]n by mechanochemical and thermal properties. The in situ experiments suggest that [(AgBr)(3-pica)]n is kinetically favoured while [(AgBr)2(3-pica)]n is converted into [(AgBr)(3-pica)]n only with a high excess of the ligand. Finally, the liquid nature of the ligands is not sufficient to assist the grinding process, and the complete reaction is observed with the addition of a small quantity of acetonitrile.

Expression of concern: Application of 1,4-bis(3-methylimidazolium-1-yl)butane ditribromide [bMImB]·(Br3)2 ionic liquid reagent for selective oxidation of sulfides to sulfoxides

Expression of concern for ‘Application of 1,4-bis(3-methylimidazolium-1-yl)butane ditribromide [bMImB]·(Br3)2 ionic liquid reagent for selective oxidation of sulfides to sulfoxides’ by Abbas Amini Manesh et al., RSC Adv., 2015, 5, 70265–70270, https://doi.org/10.1039/C5RA06182B.

Multiple on-line active valves based centrifugal microfluidics for dynamic solid-phase enrichment and purification of viral nucleic acid.

Point of care testing (POCT) of nucleic acids holds significant importance in the realm of infectious disease prevention and control, as well as the advancement of personalized precision medicine. Nevertheless, conventional nucleic acid testing methods continue to face challenges such as prolonged detection times and dependence on extensive specialized equipment and personnel, rendering them unsuitable for point of care applications. Here, we proposed an innovative active centrifugal microfluidic system (ACMS) for automatic nucleic acid extraction, encompassing modules for active valve control and magnetic control. An on-chip centrifugal puncture valve (PV) was devised based on the elastic tolerance differences between silicone membranes and tinfoils to release pre-embedded liquid reagents on demand. Furthermore, we have utilized the returnable valve (RV) technology to accurately control the retention and release of liquids, leveraging the high elastic tolerance of the silicone membrane. By incorporating an online controllable magnetic valve, we have achieved controlled and rapid aggregation and dispersion of magnetic beads. The final chip encapsulates multiple reagents and magnetic beads necessary for nucleic acid extraction. Upon sample addition and loading into the instrument, automated on-chip sample loading and nucleic acid extraction, purification, and collection can be accomplished within 30 minutes, halving the overall operation time and even increasing the efficiency of pseudovirus extraction by three orders of magnitude. Consequently, real-time fluorescence quantitative PCR amplification has successfully detected multiple targets of the SARS-CoV-2 virus (with an impressive detection limit as low as 10 copies per μL), along with targeted sequencing analysis yielding a conformity rate of 99%.

Pitfalls and Considerations in Determining the Potency and Mutant Selectivity of Covalent Epidermal Growth Factor Receptor Inhibitors.

Enzyme inhibitors that form covalent bonds with their targets are being increasingly pursued in drug development. Assessing their biochemical activity relies on time-dependent assays, which are distinct and more complex compared with methods commonly employed for reversible-binding inhibitors. To provide general guidance to the covalent inhibitor development community, we explored methods and reported kinetic values and experimental factors in determining the biochemical activity of various covalent epidermal growth factor receptor (EGFR) inhibitors. We showcase how liquid handling and assay reagents impact kinetic parameters and potency interpretations, which are critical for structure-kinetic relationships and covalent drug design. Additionally, we include benchmark kinetic values with reference inhibitors, which are imperative, as covalent EGFR inhibitor kinetic values are infrequently consistent in the literature. This overview seeks to inform best practices for developing new covalent inhibitors and highlight appropriate steps to address gaps in knowledge presently limiting assay reliability and reproducibility.

Optimization framework of sediment phosphate oxygen isotope pretreatment method based on large-scale application: A case study of Fuyang River basin

Phosphate oxygen isotope (δ18OP) technique is an effective tool to identify the source and transformation process of phosphorus. The poor applicability of existing δ18OP pretreatment methods for sediments hindered the large-scale application of δ18OP technology. This paper presents an optimization framework for the pretreatment of sediment δ18OP samples based on large-scale applications, using the Fuyang River Basin as a case study. The typical channel landscape outflow lake, South Lake, was selected as the most favorable point for assessing the applicability and optimizing the mainstream δ18OP pretreatment method, which was achieved by clarifying the sediment environmental characteristics of South Lake. To evaluate the suitability of the Blake and McLaughlin methods in South Lake, a comparative study was carried out based on five dimensions: phosphorus recovery rate, removal efficiency of organic matter, removal efficiency of extraction liquid impurity ion, experimental time, and reagent consumption cost. The findings demonstrated that the Blake method outperformed the McLaughlin method across all five dimensions. Based on the environmental characteristics of the sediments of South Lake, the Blake method was optimized from two perspectives, namely the substitution of reagents and adjustment and optimization of experimental procedures. This resulted in an enhancement of phosphorus recovery and organic matter removal efficiency, while also reducing the experimental time required. The optimized method also yielded satisfactory results when applied to the entire watershed. This research paper can thus offer valuable technical support for the widespread application of sediment δ18OP technology.

IMPROVEMENT OF THE OPERATION OF SUBMERSIBLE CONTAINERS OF DOWNHOLE UNITS FOR OIL PRODUCTION

The stable growth of oil production in the Russian Federation observed in recent years is characterized by commissioning of new fields and off-balance hydrocarbon reserves. In these conditions, occurrence of complications during operation of wells by mechanized method significantly increases the costs of enterprises and reduces the cost-effectiveness of oil production. The article presents statistical data on failures of submersible pumping units caused by complicated operating conditions. It is shown that one of the most widespread complicating factors is high corrosive activity of the well fluid and development of scaling that lead to failures of submersible pump units, reducing their operation time below the warranty period. It is indicated that out of the currently existing methods of preventing scale deposition and reducing the intensity of corrosion of downhole equipment in oil production the most technologically and economically feasible is the chemical method, which is realized through the use of inhibitors. Nowadays producers of oil and gas equipment produce in batch borehole containers for solid and encapsulated inhibitors. The main disadvantage of these submersible containers is uneven dosing of reagents into the wells. Experimental downhole submersible containers for liquid reagents are characterized by unstable and unreliable operation, complexity and high cost. The presence of significant disadvantages of experimental and commercially available submersible containers has necessitated the development of the most versatile, reliable and efficient products. The authors propose a design of a mechanized downhole submersible container equipped with a plunger pump and performing a uniform feeding of an inhibitor into a well.