Ordinary Gel Research Articles

Preparation and Properties of Composite Double-Network Gel for Inhibiting Coal Spontaneous Combustion.

In order to improve the inhibition effect of gel on coal spontaneous combustion, a chitosan (CS)/polyacrylamide (PAM)/metal ion (Al3+) composite double-network gel was developed in this study. The optimum formula of the composite double-network gel was determined using orthogonal experimentation. The microstructure, water retention, compressibility, and anti-destruction properties of the composite double-network gel were analyzed. The inhibition effect of the composite double-network gel on coal spontaneous combustion was studied via infrared spectroscopy and a synchronous thermal analyzer from the micro and macro perspectives. The results show that the composite double-network gel has a denser interpenetrating double-network structure and a larger void ratio than the ordinary gel. The water retention rate was 55% after standing at 150 °C for 12 h. The deformation memory ratio of the composite double-network gel was 78%, which was 26.8% higher than that of the ordinary gel, and the compressive strength also increased by 59.96%. In addition, the critical temperature point and the maximum thermal weight-loss rate temperature point decreased by 7.01 °C and 39.62 °C, respectively, and the composite double-network gel effectively reduced active functional groups in the treated coal sample, such as hydroxyl and aliphatic hydrocarbons. In this study, a CS/PAM/Al3+ composite double-network gel was produced, which exhibited good gel performance and inhibition effects, with physical effects such as the covering, wetting, and cementation of coal.

Research and Application of Temporary Plugging Agent Technology for High-Pressure Wells in Gas Storage Facilities

Before various construction of gas storage well, in order to ensure safety, the reservoir must be temporarily blocked, degassed by circulation and no gas in the well can be operated. There are many temporary plugging methods for oil and gas wells. This paper studies the more advanced micro mesh gel temporary plugging technology in the industry and its application in gas storage wells, which mainly solves the problems of poor degradation backflow effect and difficult permeability recovery caused by weak formation stability after temporary plugging of gas storage wells. Research points: (1) On the basis of ordinary gel, through the fusion with cross-linking agent with special structure, a micron network polymer with significant steric hindrance effect on water molecules is finally formed, which improves the strength and stability of the gel system. (2) Add hexamethylene tetramine, bisphenol propane, delayed cross-linking agent and stabilizer into the polymer aqueous solution. It is verified by laboratory tests that the micron mesh gel can be formed after constant temperature coagulation for 3h~70h at ambient temperature of 90°C~170°C. (3) The temperature resistance, permeability and gel breaking of micron mesh gel are tested in the laboratory, and the results can meet the construction requirements. (4) After the temporary plugging operation of Well Su 49K-2X in the gas storage reservoir of Huabei Oilfield is completed, the degradation products of gel breaking will flow back smoothly to ensure that the well can be put into normal injection and production quickly. The test results show that: (1) Micron mesh gel has the advantages of long plugging validity, high temperature resistance, low viscosity after gel breaking, no residue, thorough gel breaking, no formation plugging pollution, and no impact on the original reservoir permeability. It is a new green plugging technology suitable for deep buried high-temperature depleted oil and gas reservoirs. (2) Before construction, the well temperature shall be measured to conduct test injection, so as to prevent gas invasion from affecting the construction effect. The pump injection displacement is designed to be redundant, so as to prevent the low molecular solution from not reaching the design position in the well on time, and the formation of solid rubber plugs at other positions in the well from affecting the construction.

Preparation and evaluation of transdermal permeation of Huperzine A ethosomes gel in vitro

This study aimed to design and evaluate the transdermal permeation of Huperzine A ethosomes gel in vitro. Huperzine A ethosomes were prepared using the injection method, and their physical and chemical properties were characterized. A comparison was made between Huperzine A ethosomes gel, ordinary gel, and cream. The Franz diffusion cell test on mouse abdominal skin was conducted, and Huperzine A concentration was determined using LC-MS/MS. Transdermal volume, skin retention, and transdermal rate were used to assess the percutaneous permeability of the three preparations. Results demonstrated that Huperzine A ethosomes gel exhibited significantly higher accumulative permeation, transdermal rate, and skin retention compared to ordinary gel and cream. The findings suggest that Huperzine A ethosomes gel, with its controllable quality and favorable transdermal absorption properties, holds potential as a safe option for clinical administration.

Formulation and Evaluation of Microsponge Gel for Topical Delivery of Antifungal Drug

The quasi emulsion solvent diffusion technique was used to create the clotrimazole microsponges, which were eventually recognized as an efficient carrier for the topical delivery of the medicine. The characteristics of the created system were significantly affected by the drug:polymer ratio. It was discovered that microsponges made for prolonged release formulation were effective, and clotrimazole microsponges with gel produced results that were equivalent. Microsponge gel compositions that were prepared beforehand showed regulated medication release. It has been shown that microsponges can transport medications for topical antifungal therapy successfully. Given how well the formulations kept the medication on the skin, it appears that microsponge gel is a more effective drug delivery mechanism than ordinary gel.

Research on the fire extinguishing performance of new gel foam for preventing and controlling the spontaneous combustion of coal gangue.

Coal gangue, as an associated product of coal mining, can cause a large number of piles to undergo slow oxidation and spontaneous combustion, resulting in the production of toxic and harmful gases, leading to casualties, environmental damage, and economic losses. Gel foam has been extensively employed as a fire-retardant material in coal mine fire prevention. The thermal stability and rheological properties of the newly developed gel foam were investigated in this study, as well as its oxygen barrier properties and fire extinguishing effect which were evaluated through programmed temperature rise and field fire extinguishing experiments. The experiment indicated that the temperature endurance of the new gel foam was around twice that of the ordinary gel foam, and this resistance decreased with the increment of foaming times. Moreover, the temperature endurance of the new gel foam with a stabilizer concentration of 0.5% was superior to that of 0.7% and 0.3%. Temperature has a negative effect on the rheological properties of the new gel foam, while the foam stabilizer concentration has a positive effect. The oxygen barrier performance experiment results showed that the CO release rate of coal samples treated with the new gel foam rose relatively slowly with temperature, and the CO concentration of coal samples treated with the new gel foam was only 159 ppm at 100 °C, which was significantly lower than 361.1 ppm after two-phase foam treatment and 715 ppm after water treatment. Through simulating the spontaneous combustion experiment of coal gangue, it was demonstrated that the new gel foam has a much better extinguishing effect than water and traditional two-phase foam. The new gel foam cools gradually and does not re-ignite during the fire extinguishing process, while the other two materials re-ignite after being extinguished.

Acrylamide preformed particle gels with movable-crosslinking for conformance control

In order to improve the deformation ability of the preformed gel particles (PPGs), the movable-crosslinking structure was introduced into the gel network. Herein, polyrotaxane cross-linkers were synthesized by a three-step method, and acrylamide and polyrotaxane cross-linkers form gel. The structure of polyrotaxane cross-linkers was characterized by IR, HNMR, and X-ray diffraction. The findings demonstrate the successful insertion of vinyl into cyclodextrin, resulting in the formation of crosslinking points. The gel with movable-crosslinking has better deformation ability, and the breaking elongation of gel is 937%, showing excellent deformation ability Through temperature resistance and salt resistance, it shows that the expansion ratio of gel is higher than that of ordinary gel. The injectability of the gel was investigated and the sand pack plugging test was conducted. The injectivity experiment shows that the gel with movable-crosslinking has positive injectivity, can migrate to the depth of the formation, and has excellent water-plugging effect.

Preparation and characterization of antioxidant gel foam for preventing coal spontaneous combustion

New antioxidant gel foam is prepared to improve its stability and effectiveness in preventing coal spontaneous combustion. The physicochemical composite inhibitor is prepared by introducing procyanidins into a super absorbent polymer. And then the inhibitor is incorporated into the gel foam (surfactant, foam stabilizer, and gel system), the combined properties of foam, gel and inhibitor are utilized to prevent coal spontaneous combustion. The optimal composition ratio of antioxidant gel foam is obtained by single-factor experiments and response surface methodology. The microstructure of the foam is characterized. The properties of antioxidant gel foam in preventing coal spontaneous combustion are compared and analyzed through cementation, film-forming, and temperature-programmed experiments. The results reveal that the foam properties of the antioxidant gel foam are better when the mass fractions of surfactant, foam stabilizer, gel system, and inhibitor are 0.92 %, 0.49 %, 0.34 %, and 0.55 %, respectively. The inhibitor constitutes a high-water retention skeleton structure of foam wall and stabilizes the platform boundary. The antioxidant gel foam has small bubble size, uniform distribution, and excellent stability. The foam coarsening process is slow, which can fully wet the coal and reduce the coal temperature. Simultaneously, the antioxidant has better cementation and film-forming properties, which can cement the crushed coal and form a complete gel film, blocking the air leakage channels and isolating the contact between the coal and oxygen. Besides, the inhibition effect of antioxidant on coal spontaneous is better than that of water-based foam, polymer-stabilized foam, and ordinary gel foam. It can effectively slow down the oxygen consumption rate, gas production rate, and exothermic intensity during coal oxidation, the inhibition rate at 100 °C is 74.48 %. This study provides an antioxidant gel foam with good foam properties and inhibition effect, which can effectively reduce the oxidation rate of coal and prevent its spontaneous combustion through the physical effects on covering, wetting, and cementing, as well as inhibiting the chemical reaction between coal and oxygen.

Preparation and transdermal permeation of triptolide and ferulic acid ethosomes gel in vitro

The aim of this study was to prepare triptolide and ferulic acid ethosomes gel, investigate its transdermal permeation, and compare the results with ordinary gel and cream. Improved Franz diffusion cell method was used in the transdermal delivery experiment with rat abdominal skin as in vitro model. The receptor fluid at different time points was collected; ferulic acid concentration was determined by high performance liquid chromatography (HPLC) and triptolide concentration was determined by liquid chromatography-electrospray ionization mass spectrometry (LC-MS/MS). Then the penetration rate, transdermal volume and skin reserve of three dosage forms (hydroplasy gel, ordinary gel, and cream) to investigate the transdermal properties of ferulic acid and triptolide in vitro of triptolide and ferulic acid ethosomes gel. The results showed that the steady penetration rate of ferulic acid was 5.268 5, 8.990 9, 12.042 0 μg·cm⁻² ·h⁻¹ respectively in triptolide and ferulic acid ethosomes gel, ordinary gel and cream; the skin retention was (30.234 8±1.525 4), (20.402 6±0.402 6), (7.635 3±1.094 2) μg·cm⁻² . The steady-state permeation rate of triptolide was 67.238 0, 67.238 0 ng·cm⁻² ·h⁻¹ in triptolide and ferulic acid ethosomes gel, about 1.24 times of cream and 3.28 times of ordinary gel; the skin retention was (371.351 4±35.317 1) ng·cm⁻², about 3.35 times of cream and 5.25 times of ordinary gel. Therefore, the ethosomes gel showed good transdermal absorption property and it may be good for clinical safety administration.

Pharmacokinetics of bullatine A in Aconitum brachypodum total alkaloids gel in transdermal delivery

In this study, the changes of bullatine A in plasma and skin of mice with time in microemulsion gel and ordinary gel of Aconitum brachypodum total alkaloids were compared through UPLC-MS/MS, and their pharmacokinetic parameters were also compared and analyzed, to investigate the feasibility of microemulsion agent in the transdermal drug delivery. UPLC-MS/MS method for simultaneous determination of bullatine A in plasma and skin had high sensitivity and was in line with the pharmacokinetic study requirements for transdermal drug delivery. The main pharmacokinetic parameters for microemulsion gel in the plasma were as follows: Cmax=(37.62±14.31) μg•L⁻¹, Tmax=(3.40±1.34) h, AUC0-∞=(1 027.7±260) μg•L⁻¹•h⁻¹, MRT=(34.80±12.31) h, MRTlast=(10.68±0.57) h, t1/2=(23.11±9.20) h; main pharmacokinetic parameters for ordinary gel in the blood: Cmax=(52.23±15.90) μg•L⁻¹, Tmax=(4.00±0.00) h, AUC0-∞=(728.60±280.80) μg•L⁻¹•h⁻¹, MRT=(20.69±3.98) h, MRTlast=(9.34±0.42) h, t1/2=(14.69±3.15) h. The results showed that the microemulsion gel had more stable transdermal absorption, longer duration of action and higher bioavailability than ordinary gel, indicating that the microemulsion gel had a good and stable transdermal effect. There was no significant difference in bioavailability of bullatine A in skin between microemulsion gel and ordinary gel.

A low-noise multi-channel device for the monitoring of systemic electrical signal propagation in plants

Long-distance electrical signals generated in locally stimulated plants are linked with systemic physiological responses. The propagation of electrical signal through a plant can be measured by multiple electrodes attached to different sites of a plant body. As this signal has to be measured with the sensitivity of tens of microvolts, it can be easily disturbed by power-line hums or external electromagnetic fields. These disturbances can mimic the action potentials generated by a plant. In this work, we present a brief summary of various experimental approaches to the measurement of surface electrical potential (SEP) on a plant and a description of our multi-channel device for the SEP measurement. The main advantages of our measuring system are galvanic separation of the measuring unit, resulting in the elimination of power-line disturbances, and simple and stable contact of Ag/AgCl-peletted electrodes with the plant surface, facilitated by an ordinary gel used in human electrocardiography. These improvements enabled us to detect unperturbed variation (slow) and action (fast) potentials on a plant, as demonstrated by the four-electrode measurement of the electrical signal propagation in a locally wounded tomato plant.

Characterization of Amaranth and Quinoa Starches.

Starch granules were prepared from mature grains of 9 samples of Amayanthus and 4 samples of Chenopodium quinoa. By the ordinary gel permeation chromatograph (GPC) of Pseudomonas isoamylase-debranched starch materials, the amylose content of amaranth starches was in a range of 0-28%. Thus, we confirmed that there were normal, low amylose, and waxy types of amaranth starches. The amylose content of quinoa starches was 25-27%. The ratio of short chains to long chains of amylopectin of these starches was in a range of 2.2-3.3 and somewhat lower than or similar to that of normal maize starch. Isoamylase-debranched materials were separated by HPLC with a differential refractometer (RI) and low-angle laser light-scattering photometer (LALLS) as detectors as one means, and by high-performance anion exchange chromatography with a pulsed amperometric detector (HPAEC-PAD) as the other. We found that amylopectins of Amayanthus and Chenopodium quinoa had increased amounts of long B chains and decreased amounts of short chains as compared to the waxy maize amylopectin, however, they had increased amounts of short chains with DP (degree of polymerization) from 8 to 12. Amaranth starches had slightly higher temperatures of gelatinization (T0, Tp and Tc) and smaller heats of gelatinization (d H) by differential scanning calorimetry (DSC) as compared to normal maize starch. Quinoa starches showed lower T0, T p and T and smaller ΔH. Amaranth and quinoa starch granules were digested by amylases faster than those of normal maize.

Rheological Observation of a New Weak Gel in Agarose Solution

We have found a very weak gel (VWG) state in agarose solution. The VWG was distinguishable from a normal gel due to the following two differences. 1. The VWG has a very low shear modulus (below 10-2 Pa), with slight temperature dependence. 2. The VWG did not react with iodostarch, whereas the ordinary gel did. The viscosity and shear modulus were measured using a new instrument under very low constant shear stress (min., 10-4 Pa). Application of low stress made it possible to distinguish the VWG from the sol state.

Factorization and the dressing method for the Gel'fand-Dikii hierarchy

The isospectral flows of an nth order linear scalar differential operator L under the hypothesis that it possesses a Baker-Akhiezer function were originally investigated by Segal and Wilson from the point of view of infinite dimensional Grassmanians, and the reduction of the KP hierarchy to the Gel'fand-Dikii hierarchy. The associated first order systems and their formal asymptotic solutions have a rich Lie algebraic structure which was investigated by Drinfeld and Sokolov. We investigate the matrix Riemann-Hilbert factorizations for these systems, and show that different factorizations lead respectively to the potential, modified, and ordinary Gel'fand-Dikii flows. Lie algebra decompositions (the Adler- Kostant-Symes method) are obtained for the modified and potential flows. For n > 3 the appropriate factorization for the Gel'fand-Dikii flows is not a group factorization, as would be expected; yet a modification of the dressing method still works. A direct proof, based on a Fredholm determinant associated with the factorization problem, is given that the potentials are meromorphic in x and in the time variables. Potentials with Baker-Akhiezer functions include the multisoliton and rational solutions, as well as potentials in the scattering class with compactly supported scattering data. The latter are dense in the scattering class.

The isolation and characterization of a cadmium and zinc-binding protein from Tetrahymena pyriformis.

A cadmium and zinc-binding protein similar to metallothionein has been isolated from Tetrahymena pyriformis exposed to cadmium chloride. This protein contained 32.4% half-cystine, 23.7% acidic amino acids and 10.1% lysine. The amino acid composition was similar to that of copper-thionein of yeast. The metal-binding protein of Tetrahymena pyriformis contained 3.7 g atom cadmium, 0.7 g atom zinc, and 0.1 g atom copper per mol, and showed the spectral characteristics of cadmium-thionein, i.e., a broad shoulder at 250 nm and low residual absorption at 280 nm. The molecular weight of this protein was determined to be 11, 000 by gel filtration in 6m guanidine hydrochloride, although it moved like a protein with a molecular weight of 30, 000 on ordinary gel filtration.

A method for density gradient isoelectric focusing in small scale

A method for density gradient isoelectric focusing in small seale is described. It utilizes the same equipment as that ordinarily used for electrofocusing in polyacrylamide gels, thus allowing several samples to be analyzed in the same experiment and the simultaneous electrofocusing in density gradients and gels. Data concerning the stability of the pH gradient and the effect of salt and sample load on the focusing are given. Three different methods for fractionating the gradient are described; in one of these the frozen gradient is sliced with an ordinary gel alicer. This fractionation method is especially advantageous if the gradient contains zones of highly aggregated material, and it also allows the gradients to be stored frozen for later fractionation.

A rapid method for isoelectric focusing in polyacrylamide gel

During the last years different techniques for analytical gel electrofocusing have been developed and the results obtained indicate that this method gives a resolution superior to that obtained in sucrose gradients [l] . Gel electrofocusing also offers a considerable saving of time and materials [2-41. Gel rods in an ordinary disc electrophoresis apparatus were mostly used [2-51 but recently a flat bed or thin layer technique has been developed [61 l] . This offers several advantages: (i) a very simple apparatus [ 1 l] ; (ii) many samples can be run in parallel; (iii) it is simple to handle, e.g. for pH measurements; (iv) the thin gel slabs used permit efficient cooling. The effective removal of the heat evolved, was necessary to develop the ordinary gel slab electrofocusing to the rapid method described in this paper.