Gel Analysis Research Articles

Damage mechanism analysis of polymer gel to petroleum reservoirs and development of new protective methods based on NMR technique

Polymer gels are widely used in water control and enhanced oil recovery in oil fields. However, the damage mechanism of polymer gels to layers with remaining oil and not requiring plugging and corresponding protective measures are unclear. In this paper, we investigated polymer gels' damage and protection performance through static gel-breaking experiments and dynamic plugging and oil recovery evaluations on rock cores. Moreover, nuclear magnetic resonance (NMR) technology was combined to analyze the damage performance of polymer gels on cores from the pore scale. In addition, a protective technique based on gel breakers for layers with remaining oil and not requiring plugging was proposed. Results showed that when polymer gels were injected into heterogeneous cores, they plugged high-permeability layers while also penetrating low-permeability layers. When the damage to the low-permeability layers was not alleviated, the conformance and oil displacement efficiency were significantly reduced. When the concentration of ammonium persulfate was 2%–5%, the gel-breaking time was shortest and the residue was very minimal. Ammonium persulfate could be used as a gel breaker and reservoir protective material. Furthermore, after injecting ammonium persulfate into heterogeneous reservoir cores, the gel damage on the face of low-permeability layers was relieved. Consequently, the improvement in sweep efficiency was achieved, showing the re-activation of the remaining oil in medium-low permeability layers. Therefore, the low-permeability layer protection process and core experiment study based on gel-breaking agents proposed in this study were suggested to provide a new technique for the field application of conformance modification agents, aiming to achieve higher recovery degrees.

Experimental evaluation of temporary plugging performance and mechanism analysis of degradable preformed particle gel based on NMR technology

Utilizing chemical temporary plugging systems to further increase the stimulated reservoir volume (SRV) and improve oil recovery (IOR) has become a hot topic in the current petroleum industry. Pre-formed gel particles (PPG) possess excellent swelling properties and can form high-strength plugging in high-permeability channels. In addition, degradable pre-formed gel particles (DPPG) further exhibit self-degradation characteristics and excellent temporary plugging and fluid diverting performance. In our previous studies, we examined the temporary plugging mechanisms of DPPG prepared with different molecular weight (MW) of crosslinking agents (PEGDA) through bottle tests and core displacement experiments. However, the microscopic swelling mechanism and temporary plugging mechanism in pore throats of reservoir cores are still unclear. In this paper, comprehensive research was conducted on the microscopic temporary plugging mechanism of DPPG prepared with different MW crosslinking agents using both and method. Results showed that DPPG with different compositions had different micro-swelling performance. NMR-T2 analysis for bottle test showed that DPPG-M1 (with the smallest MW of crosslinking agent) gradually decreased in nuclear signal during the water absorption and swelling process, and had the largest swelling volume and swelling rate. On the other hand, DPPG-M5 (with the largest MW of crosslinking agent) exhibited a slow diffusion process of surface water towards the nucleus, resulting in the smallest swelling volume and swelling rate. However, its complete degradation time was longer. Moreover, the NMR T2 (i.e., spin-spin relaxation time) results of the cores in the dynamic temporary plugging experiment showed that the decrease of the MW of the crosslinking agent enhanced the plugging performance, but with less damage to the formation. The MRI images confirmed that DPPG-M5 had better injection capability in the core and caused greater damage to the core. The research results of this study showed that NMR technology can reveal the temporary plugging mechanism of DPPG from a micro-level perspective.

Evaluation of plant-based composite materials as 3D printed scaffolds for cell growth and proliferation in cultivated meat applications

This study aimed to evaluate plant-based 3D scaffolds for supporting the cultivation of animal cells for cultivated meat. The physical and chemical characteristics of pectin and composite gels (pectin + soy protein isolate [SPI] or pea protein isolate [PPI]) were analyzed. Rheological property analysis revealed that all materials exhibited viscoelastic solid behavior, shear thinning, and micro-structure recovery behavior, essential properties for 3D printing. Texture profile analysis (TPA) of composite gels demonstrated that some of the textural properties of these composite materials were in the range of mechanical properties of meat products including pork, poultry, and fish. The cytocompatibility and proliferative potential of these scaffold gels were evaluated using C2C12 (myoblast cells) as a model cell line, indicating their potential to support the growth of the animal cell without apparent toxicity. In examining 3D printability, incorporating protein into the pectin gel resulted in enhanced printability, characterized by reduced surface roughness and thinner thickness. Based on these analyses, a 3D printed scaffold was generated by using pectin, 30% SPI, and 10% PPI. Remarkably, the scaffolds with pectin and 10% PPI supported the growth of the cells, comparable to the cells grown on a tissue culture plate (positive control) demonstrating its potential to support animal cell growth. These findings highlight the promising potential of the formulated materials for applications within the cultivated meat industry.

Protein Extraction Methods Suitable for Muscle Tissue Proteomic Analysis.

Muscle tissue is one of the most dynamic and plastic tissues of the mammalian body and covers different roles, such as force generation and metabolic control. Muscular proteomics provides an important opportunity to reveal the molecular mechanisms behind muscle pathophysiology. To ensure successful proteomic analysis, it is necessary to have an efficient and reproducible protein extraction method. This study aimed to evaluate the efficacy of two different extraction protocols of muscle samples for two-dimensional gel electrophoresis. In particular, mouse muscle proteins were extracted by an SDS-based buffer (Method A) and by a UREA/CHAPS/DTE/TRIS solution (Method B). The efficacies of the methods were assessed by performing an image analysis of the 2DE gels and by statistical and multivariate analyses. The 2DE gels in both preparations showed good resolution and good spot overlapping. Methods A and B produced 2DE gels with different means of total spots, higher for B. Image analysis showed different patterns of protein abundance between the protocols. The results showed that the two methods extract and solubilize proteins with different chemical-physical characteristics and different cellular localizations. These results attest the efficacy and reproducibility of both protein extraction methods, which can be parallelly applied for comprehensive proteomic profiling of muscle tissue.

A Comparative Analysis of Traditional Latent Fingerprint Visualization Methods and Innovative Silica Gel G Powder Approach

Latent fingerprints are a common source of information for forensic experts and law enforcement agencies. The thin layer chromatography (TLC) plates that are prepared in this work are made with silica gel G powder. Latent fingerprint remnants are made up of secretions from the nose, palm, and sebaceous, apocrine, and eccrine glands (sweat). However, the quest for more versatile and effective techniques persisted, leading to the emergence of innovative approaches like Silica Gel G powder. The silicon atoms are linked to –OH groups at the silica gel’s surface. A latent fingerprint is an imprint left by direct contact with a surface or object that is not apparent to the unaided eye. The advantages of using Silica Gel G powder for latent fingerprint visualization underscore its significance as an innovative technique in forensic science. The latent fingerprints were developed on each of the several substrates using Merck Specialties Private Limited’s white-coloured silica gel G powder. There are several techniques in the literature for creating latent fingerprints. The emergence of Silica Gel G powder in forensic science represents a significant breakthrough in the visualization of latent fingerprints. The process of using Silica Gel G powder for latent fingerprint visualization exemplifies the precision and attention to detail required in forensic investigations.

Physiological Responses to Acute Heat Stress in Rohu, Labeo rohita: Insights from Liver Proteomics.

Heat stress is a major problem in aquaculture species, causing changes in physiology such as decreased feed intake, growth rate, reproduction, and internal cellular damage, thereby affecting fish's health. The effects of an acute heat stress simulating a daily rise and fall in temperature on summer days were evaluated in the liver proteome of rohu (Labeo rohita) fingerlings in the present study. The fish maintained at 30°C were gradually exposed to a higher temperature of 36°C at an increment rate of 1°C per 1.5h, and after 3h at that temperature, it was gradually reduced to 30°C. The liver tissue samples were collected at 5 am, 5pm, and 5 am the next day from the exposed and control fish. Protein samples were prepared from the liver tissues, and the extracted proteins were compared using 2-dimensional (2D) gel electrophoresis (2DGE) and mass spectrometry (MS) using a MALDI-TOF/TOF mass spectrometer. A total of 44 differentially expressed protein spots were visualized in 2D gel analysis from heat stress exposed fish at three time points, out of which 21 proteins including one hypothetical protein could be identified by MS. The abundance of five selected differentially expressed proteins (DEPs) was validated using qPCR. The majority of DEPs were found to be involved primarily in lipid, protein and energy metabolism, immune system regulation, cytoskeletal stability, and ROS management. The findings of this study would help in the development of strategies to mitigate heat stress in L. rohita.

Investigations of thermochemical fluids as cleanup system for polymer-based fracturing fluids

The cleanup of fracturing fluids, involving polymer degradation and well flowback, is crucial for the success of the fracturing operations and revenue generation. Breakers, such as oxidizers and enzymes, are commonly employed to break down polymers, resulting in lower viscosity, improved flowback, and facilitated well cleanup. However, these conventional breakers, which contribute solely to the cleanup process through polymer degradation, have some drawbacks, such as premature breaking and insufficient release of breakers. In this study, thermochemical fluids (TCFs) are proposed as a cleanup system. This system can improve the cleanup process by lowering viscosity through temperature increase and thermal degradation of polymers, reducing hydrostatic pressure via gas generation, and eliminating phase trapping damage in tight reservoirs through the heat produced. The TCFs investigated in this study were NH4Cl and NaNO2 solutions, where a substantial amount of heat was determined from the thermal energy study using an autoclave reactor. In this study, the thermal degradation of guar gum (GG) polymer derivatives, hydroxypropyl guar gum (HPG), and carboxymethyl hydroxypropyl guar gum (CMHPG) were assessed using Fourier Transform Infrared Spectroscopy (FTIR), Thermal Gravimetric Analysis (TGA), viscosity measurements, and coreflood experiments. Both FTIR and TGA analyses of linear gels of GG and its derivatives confirmed alterations in the chemical and thermal properties of these polymers following thermal treatments. The coreflood results showed a regained permeability of 87% for thermally treated HPG borate-crosslinked, 96% for CMHPG dual crosslinked (borate and zirconate), and 90% for slickwater fracturing fluids, respectively. The regained permeability of thermally treated slickwater was even better than that for slickwater with ammonium persulfate breaker.

Electron microscopy of stable electrophoretic fractions of natural humic acids – the key to the understanding of their structural organization

Transmission electron microscopy (TEM) with contrast staining by uranyl acetate solution was used to study morphological differences between soil humic acids (HAs) and their A, B and C + D fractions obtained using coupling preparative low-pressure size exclusion chromatography and analytical polyacrylamide gel electrophoresis. The electrophoretic mobility of fractions varied in order C + D B A. The distribution of various morphological elements between fractions showed that large structures such as vesicle-like formations 70–150 nm long and 30–80 nm wide with clear edges were found exclusively in fraction A and occupied ~55% of the TEM image area. On the other hand, long fibrils with a length of 60–100 nm, a width of 4–6 nm and a thickness of 2–3 nm, as well as their bundles with a length of 150 nm and a diameter of 30–70 nm were identified only in the C + D fraction and occupied ~59 % area of TEM images. Smaller morphological elements such as point particles with a diameter of 2–3 nm, ring particles with a diameter of 4–6 nm, worm-shaped short particles with a length of 20–30 nm, and spheroids with a diameter of 10– 30 nm were observed in all samples, but in varying quantities. Significant morphological differences between the fractions can be explained by their composition, previously established by using a few physico-chemical methods. The ratio Car(165–108 ppm)/Calk(108–0 ppm), or aromaticity index, calculated from 13C-NMR, could be one of the indicators of the various morphological structures formation. The obtained TEM results clearly confirm the supramolecular organization of soil HAs.

Analysis of homodimer formation in 12-oxophytodienoate reductase 3 in solutio and crystallo challenges the physiological role of the dimer

12-oxophytodienoate reductase 3 (OPR3) is a key enzyme in the biosynthesis of jasmonoyl-L-isoleucine, the receptor-active form of jasmonic acid and crucial signaling molecule in plant defense. OPR3 was initially crystallized as a self-inhibitory dimer, implying that homodimerization regulates enzymatic activity in response to biotic and abiotic stresses. Since a sulfate ion is bound to Y364, mimicking a phosphorylated tyrosine, it was suggested that dimer formation might be controlled by reversible phosphorylation of Y364 in vivo. To investigate OPR3 homodimerization and its potential physiological role in more detail, we performed analytical gel filtration and dynamic light scattering on wild-type OPR3 and three variants (R283D, R283E, and Y364P). The experiments revealed a rapid and highly sensitive monomer–dimer equilibrium for all OPR3 constructs. We crystallized all constructs with and without sulfate to examine its effect on the dimerization process and whether reversible phosphorylation of Y364 triggers homodimerization in vivo. All OPR3 constructs crystallized in their monomeric and dimeric forms independent of the presence of sulfate. Even variant Y364P, lacking the putative phosphorylation site, was crystallized as a self-inhibitory homodimer, indicating that Y364 is not required for dimerization. Generally, the homodimer is relatively weak, and our results raise doubts about its physiological role in regulating jasmonate biosynthesis.

Glucose-Regulated Protein 78, via Releasing β-Catenin from Adherens Junctions, Facilitates Its Interaction with STAT3 in Mediating Retinal Neovascularization

Retinopathy due to neovascularization is one of the major causes of vision loss. To understand the mechanisms underlying retinal neovascularization, using the oxygen-induced retinopathy (OIR) model, we performed two-dimensional gel matrix-assisted laser desorption/ionization time-of-flight/time-of-flight analysis of normoxic and 24-hour post-OIR mice pups' retinas. Two-dimensional gel analysis revealed that glucose-regulated protein 78 (GRP78) is one of the several molecules induced by OIR in the retinal endothelial cells (ECs). Vascular endothelial growth factor A (VEGFA) also induced GRP78 expression independent of endoplasmic reticulum stress response in human retinal microvascular endothelial cells, and depletion of its levels reduced VEGFA-induced EC angiogenic responses. Consistent with these observations, EC-specific deletion of GRP78 inhibited OIR-induced retinal neovascularization. In exploring the mechanisms, we found that GRP78 binds with vascular endothelial-cadherin and releases adherens junction- but not Wnt-mediated β-catenin and that β-catenin, in turn, via interacting with STAT3, triggers cyclin D1 expression. Furthermore, depletion of β-catenin or cyclin D1 levels negated VEGFA-induced EC angiogenic responses and OIR-induced retinal neovascularization. EC-specific deletion of GRP78 also suppressed OIR-induced vascular leakage. In elucidating the upstream signaling, we found that activating transcription factor 6 mediates GRP78 induction in the modulation of VEGFA-induced EC angiogenic responses and OIR-induced retinal neovascularization. Together, these observations reveal that GRP78, independent of its response to endoplasmic reticulum stress, is involved in mediating EC angiogenic responses by VEGFA and retinal neovascularization by OIR. In view of these findings, it appears that GRP78 could be a desirable target for drug development against diabetic retinopathy.

Clinical applicability of Linac-integrated CBCT based NIPAM 3D dosimetry: a dual-institutional investigation

Objective. To develop and benchmark a novel 3D dose verification technique consisting of polymer gel dosimetry (PGD) with cone-beam-CT (CBCT) readout through a two-institution study. The technique has potential for wide and robust applicability through reliance on CBCT readout. Approach. Three treatment plans (3-field, TG119-C-shape spine, 4-target SRS) were created by two independent institutions (Institutions A and B). A Varian Truebeam linear accelerator was used to deliver the plans to NIPAM polymer gel dosimeters produced at both institutions using an identical approach. For readout, a slow CBCT scan mode was used to acquire pre- and post-irradiation images of the gel (1 mm slice thickness). Independent gel analysis tools were used to process the PGD images (A: VistaAce software, B: in-house MATLAB code). Comparing planned and measured doses, the analysis involved a combination of 1D line profiles, 2D contour plots, and 3D global gamma maps (criteria ranging between 2%1 mm and 5%2 mm, with a 10% dose threshold). Main results. For all gamma criteria tested, the 3D gamma pass rates were all above 90% for 3-field and 88% for the SRS plan. For the C-shape spine plan, we benchmarked our 2% 2 mm result against previously published work using film analysis (93.4%). For 2%2 mm, 99.4% (Institution A data), and 89.7% (Institution B data) were obtained based on VistaAce software analysis, 83.7% (Institution A data), and 82.9% (Institution B data) based on MATLAB. Significance. The benchmark data demonstrate that when two institutions follow the same rigorous procedures gamma passing rates up to 99%, for 2%2 mm criteria can be achieved for substantively different treatment plans. The use of different software and calibration techniques may have contributed to the variation in the 3D gamma results. By sharing the data across institutions, we observe the gamma passing rate is more consistent within each pipeline, indicating the need for standardized analysis methods.

Upcycling soybean meal through enzymatic conversion of insoluble fiber into soluble dietary fiber enhanced by ball milling.

Insoluble dietary fiber (IDF) in soybean meal, due to the insolubility, is one of the major impediments to upcycle the soybean meal for its value-added use. This study converted IDF to soluble dietary fiber (SDF) using ball milling and enzymatic hydrolysis of the IDF. The impact of ball milling and enzymatic hydrolysis on the physicochemical and functional properties of SDF was evaluated. Cellulase, hemicellulase, xylanase, galacturonase, and arabinofuranosidase were employed for hydrolyzing IDF. The results showed that ball milling significantly reduced the particle size of IDF, facilitating enhanced enzymatic hydrolysis and resulting in SDF with lower molecular weight and varied monosaccharide composition. The synergistic effect of ball milling and enzymatic processes with combination of cellulase-xylanase-galacturonase was evident by the improved conversion rates (69.8%) and altered weight-averaged molecular weight (<5900 Da) of the resulting SDF. Rheological and microstructural analyses of the SDF gel indicated that specific enzyme combinations led to SDF gels with distinct viscoelastic properties, pore sizes, and functional capabilities, suitable for varied applications in the food and pharmaceutical sectors. This comprehensive evaluation demonstrates the potential of optimized physical bioprocessing techniques in developing functional ingredients with tailored properties for industrial use.

High-Throughput Screening for Oligonucleotide Detection by ADE-OPI-MS.

Oligonucleotides represent a class of shorter DNA or RNA nucleic acid polymers extensively applied in the biomedical field. Despite progress in detecting and analyzing oligonucleotides, high-throughput analysis of the samples remains challenging. In this work, a high-throughput analysis method for oligonucleotide analysis was developed based on acoustic droplet ejection-open port interface-mass spectrometry (ADE-OPI-MS) technology. This approach was applied to determine the enzymatic activity of terminal deoxynucleotide transferase (TdT) for DNA synthesis, with a rate of 3 s/sample, which enhanced single-sample analysis efficiency approximately 60-fold over the previous gel analysis. After testing approximately 10,000 TdT mutants, we obtained three new variants with higher catalytic activities. Finally, by integrating these mutants, the catalytic activity of TdT was improved about 4 times compared to the starting mutant. Our results successfully established a high-throughput screening method for oligonucleotide analysis, which not only provides a foundation to engineer highly efficient TdT for ab initio synthesis of DNA but also paves the way for the potential application of oligonucleotide analysis in biomedical fields.

Electromechanical Performances of Polyvinyl Chloride Gels Using (Polyvinyl Chloride-Co-Vinyl Acetate) (P(VC-VA)) Synergistic Plasticization.

The current polyvinyl chloride (PVC) gel flexible actuators are facing challenges of high input voltage and an insufficient elastic modulus. In this study, we conducted a detailed study on the properties of PVC gel prepared by introducing the modifier polyvinyl chloride-vinyl acetate (P(VC-VA)). We compared a modified PVC gel with the traditional one in terms of the relative dielectric constant, mechanical modulus, and electromechanical actuation performance. Experimental results demonstrated that the introduction of P(VC-VA) enhanced the dielectric constant and reduced the driving electric field strength of PVC gels. The dielectric constant increased from 4.77 to 7.3. The electromechanical actuation performance increased by 150%. We employed the Gent model to fit the experimental results, and the actual experimental data aligned well with the expectations of the Gent model. The research results show that this type of plasticizing method effectively balanced the mechanical and electrical performance of PVC gels. This study summarizes the experimental results and performance analysis of PVC gels prepared using innovative plasticization methods, revealing the potential engineering applications of polymeric gels.

Customizable BAC-based DNA markers for pulsed-field gel electrophoresis

DNA markers are used as a size reference and sample loading control during gel electrophoresis. Most markers are designed for conventional gel electrophoresis to separate DNA smaller than 20 kb. For larger molecules, pulsed-field gel electrophoresis (PFGE) marker is required. Limited PFGE markers are available because large DNA are prone to nicking and degradation, causing smeary bands. Here, we developed a robust marker based on bacterial artificial chromosomes (BACs) with bands up to 184 kb. This marker could consistently confer intense and distinct bands for accurate gel analysis in molecular biology studies, laboratory validations or clinical diagnosis.

A folding motif formed with an expanded genetic alphabet

Adding synthetic nucleotides to DNA increases the linear information density of DNA molecules. Here we report that it also can increase the diversity of their three-dimensional folds. Specifically, an additional nucleotide (dZ, with a 5-nitro-6-aminopyridone nucleobase), placed at twelve sites in a 23-nucleotides-long DNA strand, creates a fairly stable unimolecular structure (that is, the folded Z-motif, or fZ-motif) that melts at 66.5 °C at pH 8.5. Spectroscopic, gel and two-dimensional NMR analyses show that the folded Z-motif is held together by six reverse skinny dZ−:dZ base pairs, analogous to the crystal structure of the free heterocycle. Fluorescence tagging shows that the dZ−:dZ pairs join parallel strands in a four-stranded compact down–up–down–up fold. These have two possible structures: one with intercalated dZ−:dZ base pairs, the second without intercalation. The intercalated structure would resemble the i-motif formed by dC:dC+-reversed pairing at pH ≤ 6.5. This fZ-motif may therefore help DNA form compact structures needed for binding and catalysis.

Carbopol 934-based transethosomal gel of Glycyrrhizic acid for the management of skin cancer

Glycyrrhizic acid (GA) exhibited potential anti-cancer efficacy and was used for the treatment of skin cancer. Transethosomes were developed to improve the solubility, bioavailability, and permeability of GA since it shows high solubility in ethanol. The topical route offers the benefits of higher patient compliance, easy administration, and withdrawal in case of any side effects. The GA loaded transethosome (GA-TE) was optimized by using the Box-Behnken design. The optimized GA-TE formulation was characterized for vesicle size, and zeta potential, which were 127.6 ± 0.8 nm and −24.41 ± 0.7 mV respectively. The % entrapment efficiency and % drug loading of the optimized GA-TE formulation were found to be 85.22 ± 0.94 % and 6.22 ± 0.43 % respectively. The prepared GA-TE formulation was converted to topical gel by incorporating 1 % Carbopol 934 as a gelling agent. The texture analysis of GA-TE gel showed that the values of cohesiveness, work of cohesion, consistency, and firmness were suitable for the topical delivery system for skin cancer as compared to the conventional gel. The results of ex-vivo and in-vitro permeation of GA-TE gel showed better and enhanced permeation than conventional gel. The confocal laser scanning microscopy results showed better permeation, retention, deposition, and distribution of rhodamine B-loaded GA-TE gel formulation into the skin as compared to conventional gel. The produced GA-TE formulation was proven to be beneficial in treating skin cancer based on the in-vivo results.

Electrophoretic method and assessing the formation of an RNA-interfering complex with miR775A in corn leaves under the conditions of normoxia and hypoxia

Oxidative processes in cells, in particular mitochondrial respiration, are most sensitive to a lack of oxygen, therefore, it requires cell metabolism coordination. MicroRNAs are one of the tools of the molecular epigenetic regulation. These are a class of non-coding small RNA molecules (20-22 nt) that are able to regulate target genes expression at the post-transcriptional level by inhibiting the translation or cleavage of their mRNAs. It is known that microRNAs can act by RNA interference or can bind to an RNA-induced transcriptional silencing (RITS) complex. The study of the role of microRNAs in the adaptive response of cell metabolism to hypoxic stress as a mechanism of molecular control is of particular interest. Phenol-chloroform extraction with a specific precipitant for LiCl ribonucleic acids made it possible to obtain the total cellular RNA from corn leaves. The resulting RNA preparations were of good quality, which was indicated by the presence of 2 distinct bands of 28S and 18S rRNA and the absence of traces of degradation. The resulting preparations of total cellular RNA were used as a matrix to assess the formation of RNA interfering complexes which formed as RNA:RNA duplexes based on complementarity between microRNA775A and the target mRNA. The method of analytical agarose gel electrophoresis with a specific fluorescent probe with ROX was used to assess the formation of an RNA interfering complex with miR775A. This method made it possible to identify the ratio of the number of formed RNA-interfering complexes of cell mRNA with miR775A separated on the basis of their molecular masses in the samples under hypoxic conditions. Electrophoresis in agarose gel followed by densitometry revealed the presence of only one interfering complex with an electrophoretic mobility of 0.23-0.25 units. The results showed that miR775A interacted with a single target mRNA in corn leaf cells under normal conditions and under the conditions of hypoxia. Quantitative assessment of the fluorescence intensity of the formed complex of mRNA-miR775A-probe by ROX emission indicated an increase in the analysed indicator in samples isolated from corn leaves under hypoxic stress.

A PCR Test Using the Mini-PCR Platform and Simplified Product Detection Methods Is Highly Sensitive and Specific to Detect Fasciola hepatica DNA Mixed in Human Stool, Snail Tissue, and Water DNA Specimens.

Fasciola hepatica has a complex lifecycle with multiple intermediate and definitive hosts and influenced by environmental factors. The disease causes significant morbidity in children and its prevalent worldwide. There is lack of data about distribution and burden of the disease in endemic regions, owing to poor efficacy of the different diagnostic methods used. A novel PCR-based test was developed by using a portable mini-PCR® platform to detect Fasciola sp. DNA and interpret the results via a fluorescence viewer and smartphone image analyzer application. Human stool, snail tissue, and water samples were used to extract DNA. Primers targeting the ITS-1 of the 18S rDNA gene of Fasciola sp. were used. The limit of detection of the mini-PCR test was 1 fg/μL for DNA samples diluted in water, 10 fg/μL for Fasciola/snail DNA scramble, and 100 fg/μL for Fasciola/stool DNA scramble. The product detection by agarose gel, direct visualization, and image analyses showed the same sensitivity. The Fh mini-PCR had a sensitivity and specificity equivalent to real-time PCR using the same specimens. Testing was also done on infected human stool and snail tissue successfully. These experiments demonstrated that Fh mini-PCR is as sensitive and specific as real time PCR but without the use of expensive equipment and laboratory facilities. Further testing of multiple specimens with natural infection will provide evidence for feasibility of deployment to resource constrained laboratories.

Preparation and Performance of High-Temperature-Resistant, Degradable Inorganic Gel for Steam Applications

Summary To address the problems of steam channeling caused by the nonhomogeneity and fluid compatibility of the reservoir in heavy oil reservoirs and the permanent damage to the reservoir easily caused by traditional plugging agents, this study adopted polyaluminum chloride (PAC) as the main agent, urea as the coagulant promoter, and thiourea as the stabilizer and prepared a high-temperature-resistant (up to 350°C) degradable inorganic aluminum gel with excellent performance. Initially, scanning electron microscope (SEM) tests were conducted on gels with and without urea. Energy-dispersive X-ray spectroscopy (EDS)-mapping analysis of gels immersed in water with different mineralization levels for 5 days was then performed. The results revealed that the addition of urea led to a tighter and more complete crosslinked structure, significantly enhancing the mechanical strength of the gel. As water mineral content increased, the gel’s microstructure became denser and smoother. Metal cations on the cross-sectional surface increased gradually and distributed uniformly, further confirming the mechanism of the synergistic salt effect of soluble strong electrolytes and urea in strengthening the gel. Finally, the plugging and degradable properties of the gel were evaluated, and the results showed that the plugging percentage of the gel could still reach 97.6% after aging at 350°C for 30 days, and the gel had excellent plugging and diversion in dual sandpack experiments where the permeability ratio was less than 44. At 250°C, the degradation percentage of the gel was more than 98% at 5 days under the nonacid degradation system and 94% at 5 days under the acid degradation system. The gel showed good degradability and effectively reduced the damage to the reservoir.