Activation of endogenous neurogenesis and angiogenesis by basic fibroblast growth factor-chitosan gel in an adult rat model of ischemic stroke

Attempts have been made to use cell transplantation and biomaterials to promote cell proliferation,differentiation,migration,and survival,as well as angiogenesis,in the context of brain injury.However,whether bioactive materials can repair the damage caused by ischemic stroke by activating endogenous neurogenesis and angiogenesis is still unknown.In this study,we applied chitosan gel loaded with basic fibroblast growth factor to the stroke cavity 7 days after ischemic stroke in rats.The gel slowly released basic fibroblast growth factor,which improved the local microenvironment,activated endogenous neural stem/progenitor cells,and recruited these cells to migrate toward the penumbra and stroke cavity and subsequently differentiate into neurons,while enhancing angiogenesis in the penumbra and stroke cavity and ultimately leading to partial functional recovery.This study revealed the mechanism by which bioactive materials repair ischemic strokes,thus providing a new strategy for the clinical application of bioactive materials in the treatment of ischemic stroke.

Trend of Developing Aqueous Liquid and Gel Electrolytes for Sustainable,Safe,and High‑Performance Li‑Ion Batteries

Current lithium-ion batteries(LIBs)rely on organic liquid electrolytes that pose significant risks due to their flammability and toxicity.The potential for environmental pollution and explosions resulting from battery damage or fracture is a critical concern.Water-based(aqueous)electrolytes have been receiving attention as an alternative to organic electrolytes.However,a narrow electrochemicalstability window,water decomposition,and the consequent low battery operating voltage and energy density hinder the practical use of aqueous electrolytes.Therefore,developing novel aqueous electrolytes for sustainable,safe,high-performance LIBs remains challenging.This Review first commences by summarizing the roles and requirements of electrolytes–separators and then delineates the progression of aqueous electrolytes for LIBs,encompassing aqueous liquid and gel electrolyte development trends along with detailed principles of the electrolytes.These aqueous electrolytes are progressed based on strategies using superconcentrated salts,concentrated diluents,polymer additives,polymer networks,and artificial passivation layers,which are used for suppressing water decomposition and widening the electrochemical stability window of water of the electrolytes.In addition,this Review discusses potential strategies for the implementation of aqueous Li-metal batteries with improved electrolyte–electrode interfaces.A comprehensive understanding of each strategy in the aqueous system will assist in the design of an aqueous electrolyte and the development of sustainable and safe high-performance batteries.

Alleviation of the plastic deformation of gel ink under strong stress through an esterification of xanthan gum reinforcing its double helix structure

As a natural organic polymer,xanthan gum(XG)can alleviate the plastic deformation of gel ink under strong stress and realize the reasonable regulation of the rheological properties of gel ink.However,as the double-helix structure connected by hydrogen bonds cannot resist the mechanical environment of strong stress,XG shows poor shear resistance.In this study,a polymer gel with interpenetrating polymer network structure was prepared by esterifying XG,taking polystyrene maleic anhydride(SMA)as the modifier.In addition to retaining the excellent rheological properties of XG,the generated polymer gel also exhibited high shear resistance.The optimal addition amount of the esterification reaction modifier was determined as mXG:mSMA=5:3 according to the gel ink standard.With this amount,the viscosity of the modified xanthan gum(SXG)gel increased to 1578.8 mPa·s and 100.7 mPa·s at shear rates of 4 s1 and 383 s1,respectively,and the shear resistance increased more than 2 times compared to the unmodified one.It is because of the ester bond formed by esterification that the reaction strengthens the interaction between molecular segments,enabling the new gel to resist to strong mechanical stress.The new polymer gel studied in this paper and the proposed mechanism of action provide new insights for the development of high-end gel ink and also provide theoretical support for the study of rheological properties of non-Newtonian fluids.

A novel profile modification HPF-Co gel satisfied with fractured low permeability reservoirs in high temperature and high salinity

Conformance control and water plugging are a widely used EOR method in mature oilfields.However,majority of conformance control and water plugging agents are unavoidable dehydrated situation in high-temperature and high-salinity low permeability reservoirs.Consequently,a novel conformance control system HPF-Co gel,based on high-temperature stabilizer(CoCl_(2)·H_(2)O,CCH)is developed.The HPF-Co bulk gel has better performances with high temperature(120℃)and high salinity(1×10^(5)mg/L).According to Sydansk coding system,the gel strength of HPF-Co with CCH is increased to code G.The dehydration rate of HPF-Co gel is 32.0%after aging for 150 d at 120℃,showing excellent thermal stability.The rheological properties of HPF gel and HPF-Co gel are also studied.The results show that the storage modulus(G′)of HPF-Co gel is always greater than that of HPF gel.The effect of CCH on the microstructure of the gel is studied.The results show that the HPF-Co gel with CCH has a denser gel network,and the diameter of the three-dimensional network skeleton is 1.5-3.5μm.After 90 d of aging,HPF-Co gel still has a good three-dimensional structure.Infrared spectroscopy results show that CCH forms coordination bonds with N and O atoms in the gel amide group,which can suppress the vibration of cross-linked sites and improve the stability at high temperature.Fractured core plugging test determines the optimized polymer gel injection strategy and injection velocity with HPF-Co bulk gel system,plugging rate exceeding 98%.Moreover,the results of subsequent waterflooding recovery can be improved by 17%.

A Gel-Based Solidification Technology for Large Fracture Plugging

Fault fractures usually have large openings and considerable extension. Accordingly, cross-linked gel materials aregenerally considered more suitable plugging agents than water-based gels because the latter often undergo contaminationvia formation water, which prevents them from being effective over long times. Hence, in this study, aset of oil-based composite gels based on waste grease and epoxy resin has been developed. These materials havebeen observed to possess high compressive strength and resistance to the aforementioned contamination, therebyleading to notable increase in plugging success rate. The compressive strength, thickening time, and resistance toformation water pollution of these gels have been evaluated indoors. The results show that the compressivestrength of the gel can reach 11 MPa;additionally, the related gelation time can be controlled to be more than3 h, thereby providing a safe construction time;Invasion of formation water has a small effect on the gel strengthand does not shorten the thickening time. All considered performance indicators of the oil-based gel confirm itssuitability as a plugging agent for fault fractures.

Gypsum-based Silica Gel Humidity-controlling Composite Materials:Preparation,Characterization,and Performance

Gypsum was used as substrate,and silica gel was mixed into substrate at a certain mass ratio to prepare humidity-controlling composites;moreover,the moisture absorption and desorption properties of gypsum-based composites were compared with adding different silica gel particle size and proportion.The morphological characteristics,the isothermal equilibrium moisture content curve,moisture absorption and desorption rate,moisture absorption and desorption stability,and humidity-conditioning performance were tested and analyzed.The experimental results show that,compared with pure-gypsum,the surface structure of the gypsum-based composites is relatively loose,the quantity,density and aperture of the pores in the structure increase.The absorption and desorption capacity increase along with the increase of silica gel particle size and silica gel proportion.When 3 mm silica gel particle size is added with a mass ratio of 40%,the maximum equilibrium moisture content of humidity-controlling composites is 0.161 g/g at 98% relative humidity(RH),3.22 times that of pure-gypsum.The moisture absorption and desorption rates are increased,the equilibrium moisture absorption and desorption rates are 2.68 times and 1.61 times that of pure-gypsum at 58.5% RH,respectively.The gypsum-based composites have a good stability,which has better timely response to dynamic humidity changes and can effectively regulate indoor humidity under natural conditions.

Bacterial Cellulose/Zwitterionic Dual-network Porous Gel Polymer Electrolytes with High Ionic Conductivity

Bacterial cellulose(BC)was innovatively combined with zwitterionic copolymer acrylamide and sulfobetaine methacrylic acid ester[P(AM-co-SBMA)]to build a dual-network porous structure gel polymer electrolytes(GPEs)with high ionic conductivity.The dual network structure BC/P(AM-co-SBMA)gels were formed by a simple one-step polymerization method.The results show that ionic conductivity of BC/P(AM-co-SBMA)GPEs at the room temperature are 3.2×10^(-2) S/cm@1 M H_(2)SO_(4),4.5×10^(-2) S/cm@4 M KOH,and 3.6×10^(-2) S/cm@1 M NaCl,respectively.Using active carbon(AC)as the electrodes,BC/P(AM-co-SBMA)GPEs as both separator and electrolyte matrix,and 4 M KOH as the electrolyte,a symmetric solid supercapacitors(SSC)(AC-GPE-KOH)was assembled and testified.The specific capacitance of AC electrode is 173 F/g and remains 95.0%of the initial value after 5000 cycles and 86.2%after 10,000 cycles.

Study of deep transportation and plugging performance of deformable gel particles in porous media

Deformable gel particles(DGPs) possess the capability of deep profile control and flooding. However, the deep migration behavior and plugging mechanism along their path remain unclear. Breakage, an inevitable phenomenon during particle migration, significantly impacts the deep plugging effect. Due to the complexity of the process, few studies have been conducted on this subject. In this paper, we conducted DGP flow experiments using a physical model of a multi-point sandpack under various injection rates and particle sizes. Particle size and concentration tests were performed at each measurement point to investigate the transportation behavior of particles in the deep part of the reservoir. The residual resistance coefficient and concentration changes along the porous media were combined to analyze the plugging performance of DGPs. Furthermore, the particle breakage along their path was revealed by analyzing the changes in particle size along the way. A mathematical model of breakage and concentration changes along the path was established. The results showed that the passage after breakage is a significant migration behavior of particles in porous media. The particles were reduced to less than half of their initial size at the front of the porous media. Breakage is an essential reason for the continuous decreases in particle concentration, size, and residual resistance coefficient. However, the particles can remain in porous media after breakage and play a significant role in deep plugging. Higher injection rates or larger particle sizes resulted in faster breakage along the injection direction, higher degrees of breakage, and faster decreases in residual resistance coefficient along the path. These conditions also led to a weaker deep plugging ability. Smaller particles were more evenly retained along the path, but more particles flowed out of the porous media, resulting in a poor deep plugging effect. The particle size is a function of particle size before injection, transport distance, and different injection parameters(injection rate or the diameter ratio of DGP to throat). Likewise, the particle concentration is a function of initial concentration, transport distance, and different injection parameters. These models can be utilized to optimize particle injection parameters, thereby achieving the goal of fine-tuning oil displacement.

Effect of sodium starch octenyl succinate-based Pickering emulsion on the physicochemical properties of hairtail myofibrillar protein gel subjected to multiple freeze-thaw cycles

A Pickering emulsion based on sodium starch octenyl succinate(SSOS)was prepared and its effects on the physicochemical properties of hairtail myofibrillar protein gels(MPGs)subjected to multiple freeze-thaw(F-T)cycles were investigated.The whiteness,water-holding capacity,storage modulus(G')and texture properties of the MPGs were significantly improved by adding 1%-2%Pickering emulsion(P<0.05).Meanwhile,Raman spectral analysis demonstrated that Pickering emulsion promoted the transformation of secondary structure,enhanced hydrogen bonds and hydrophobic interactions,and promoted the transition of disulfide bond conformation from g-g-g to g-g-t and t-g-t.At an emulsion concentration of 2%,theα-helix content decreased by 10.37%,while theβ-sheet content increased by 7.94%,compared to the control.After F-T cycles,the structure of the MPGs was destroyed,with an increase in hardness and a decrease in whiteness and water-holding capacity,however,the quality degradation of MPGs was reduced with 1%-2%Pickering emulsion.These findings demonstrated that SSOS-Pickering emulsions,as potential fat substitutes,can enhance the gel properties and the F-T stability of MPGs.

Protective performance of shear stiffening gel-modified foam against ballistic impact:Experimental and numerical study

As one of the most widely used personal protective equipment(PPE),body armors play an important role in protecting the human body from the high-velocity impact of bullets or projectiles.The body torso and critical organs of the wear may suffer severe behind-armor blunt trauma(BABT)even though the impactor is stopped by the body armor.A type of novel composite material through incorporating shear stiffening gel(STG)into ethylene-vinyl acetate(EVA)foam is developed and used as buffer layers to reduce BABT.In this paper,the protective performance of body armors composed of fabric bulletproof layers and a buffer layer made of foam material is investigated both experimentally and numerically.The effectiveness of STG-modified EVA in damage relief is verified by ballistic tests.In parallel with the experimental study,numerical simulations are conducted by LS-DYNA®to investigate the dynamic response of each component and capture the key mechanical parameters,which are hardly obtained from field tests.To fully describe the material behavior under the transient impact,the selected constitutive models take the failure and strain rate effect into consideration.A good agreement between the experimental observations and numerical results is achieved to prove the validity of the modelling method.The tests and simulations show that the impact-induced deformation on the human body is significantly reduced by using STG-modified EVA as the buffering material.The improvement of protective performance is attributed to better dynamic properties and more outstanding energy absorption capability of the composite foam.

Metal–Organic Gel Leading to Customized Magnetic‑Coupling Engineering in Carbon Aerogels for Excellent Radar Stealth and Thermal Insulation Performances

Metal–organic gel(MOG)derived composites are promising multi-functional materials due to their alterable composition,identifiable chemical homogeneity,tunable shape,and porous structure.Herein,stable metal–organic hydrogels are prepared by regulating the complexation effect,solution polarity and curing speed.Meanwhile,collagen peptide is used to facilitate the fabrication of a porous aerogel with excellent physical properties as well as the homogeneous dispersion of magnetic particles during calcination.Subsequently,two kinds of heterometallic magnetic coupling systems are obtained through the application of Kirkendall effect.FeCo/nitrogen-doped carbon(NC)aerogel demonstrates an ultra-strong microwave absorption of−85 dB at an ultra-low loading of 5%.After reducing the time taken by atom shifting,a FeCo/Fe3O4/NC aerogel containing virus-shaped particles is obtained,which achieves an ultra-broad absorption of 7.44 GHz at an ultra-thin thickness of 1.59 mm due to the coupling effect offered by dual-soft-magnetic particles.Furthermore,both aerogels show excellent thermal insulation property,and their outstanding radar stealth performances in J-20 aircraft are confirmed by computer simulation technology.The formation mechanism of MOG is also discussed along with the thermal insulation and electromagnetic wave absorption mechanism of the aerogels,which will enable the development and application of novel and lightweight stealth coatings.

Bifunctional TiO_(2-x)nanofibers enhanced gel polymer electrolyte for high performance lithium metal batteries

Exploration of advanced gel polymer electrolytes(GPEs)represents a viable strategy for mitigating dendritic lithium(Li)growth,which is crucial in ensuring the safe operation of high energy density Li metal batteries(LMBs).Despite this,the application of GPEs is still hindered by inadequate ionic conductivity,low Li^(+)transference number,and subpar physicochemical properties.Herein,Ti O_(2-x)nanofibers(NF)with oxygen vacancy defects were synthesized by a one-step process as inorganic fillers to enhance the thermal/mechanical/ionic-transportation performances of composite GPEs.Various characterizations and theoretical calculations reveal that the oxygen vacancies on the surface of Ti O_(2-x)NF accelerate the dissociation of Li PF_6,promote the rapid transfer of free Li^(+),and influence the formation of Li F-enriched solid electrolyte interphase.Consequently,the composite GPEs demonstrate enhanced ionic conductivity(1.90m S cm^(-1)at room temperature),higher lithium-ion transference number(0.70),wider electrochemical stability window(5.50 V),superior mechanical strength,excellent thermal stability(210℃),and improved compatibility with lithium,resulting in superior cycling stability and rate performance in both Li||Li,Li||Li Fe PO_(4),and Li||Li Ni_(0.8)Co_(0.1)Mn_(0.1)O_(2)cells.Overall,the synergistic influence of nanofiber morphology and enriched oxygen vacancy structure of fillers on electrochemical properties of composite GPEs is comprehensively investigated,thus,it is anticipated to shed new light on designing high-performance GPEs LMBs.

Efficacy of Huangma Ding or autologous platelet-rich gel for the diabetic lower extremity arterial disease patients with foot ulcers

BACKGROUND Diabetes foot is one of the most serious complications of diabetes and an important cause of death and disability,traditional treatment has poor efficacy and there is an urgent need to develop a practical treatment method.AIM To investigate whether Huangma Ding or autologous platelet-rich gel(APG)treatment would benefit diabetic lower extremity arterial disease(LEAD)patients with foot ulcers.METHODS A total of 155 diabetic LEAD patients with foot ulcers were enrolled and divided into three groups:Group A(62 patients;basal treatment),Group B(38 patients;basal treatment and APG),and Group C(55 patients;basal treatment and Huangma Ding).All patients underwent routine follow-up visits for six months.After follow-up,we calculated the changes in all variables from baseline and determined the differences between groups and the relationships between parameters.RESULTS The infection status of the three groups before treatment was the same.Procalcitonin(PCT)improved after APG and Huangma Ding treatment more than after traditional treatment and was significantly greater in Group C than in Group B.Logistic regression analysis revealed that PCT was positively correlated with total amputation,primary amputation,and minor amputation rates.The ankle-brachial pressure and the transcutaneous oxygen pressure in Groups B and C were greater than those in Group A.The major amputation rate,minor amputation rate,and total amputation times in Groups B and C were lower than those in Group A.CONCLUSION Our research indicated that diabetic foot ulcers(DFUs)lead to major amputation,minor amputation,and total amputation through local infection and poor microcirculation and macrocirculation.Huangma Ding and APG were effective attreating DFUs.The clinical efficacy of Huangma Ding was better than that of autologous platelet gel,which may be related to the better control of local infection by Huangma Ding.This finding suggested that in patients with DFUs combined with coinfection,controlling infection is as important as improving circulation.

Research Progress of Polymer Fire Extinguishing Gel and Its Application in Forest Fire Prevention

The paper summarizes the structure and water-absorbing mechanism,classification,and preparation method of polymer fire extinguishing gel,and prospects for its application in aerial firefighting,forest ground fire extinguishing,opening of firebreaks,and mitigating human casualties in forest fire extinguishing.

All-Climate Stretchable Dendrite-Free Zn-Ion Hybrid Supercapacitors Enabled by Hydrogel Electrolyte Engineering

Hybrid supercapacitors have shown great potentials to fulfill the demand of future diverse applications such as electric vehicles and portable/wearable electronics.In particular,aqueous zinc-ion hybrid supercapacitors(ZHSCs)have gained much attention due to their low-cost,high energy density,and environmental friendliness.Nevertheless,typical ZHSCs use Zn metal anode and normal liquid electrolyte,causing the dendrite issue,restricted working temperature,and inferior device flexibility.Herein,a novel flexible Zn-ion hybrid supercapacitor(FZHSC)is developed by using activated carbon(AC)anode,δ-MnO_(2) cathode,and innovative PVA-based gel electrolyte.In this design,heavy Zn anode and its dendrite issue are avoided and layered cathode with large interlayer spacing is employed.In addition,flexible electrodes are prepared and integrated with an anti-freezing,stretchable,and compressible hydrogel electrolyte,which is attained by simultaneously using glycerol additive and freezing/thawing technique to regulate the hydrogen bond and microstructure.The resulting FZHSC exhibits good rate capability,high energy density(47.86 Wh kg^(−1);3.94 mWh cm^(−3)),high power density(5.81 kW kg^(−1);480 mW cm^(−3)),and excellent cycling stability(~91%capacity retention after 30000 cycles).Furthermore,our FZHSC demonstrates outstanding flexibility with capacitance almost unchanged even after various continuous shape deformations.The hydrogel electrolyte still maintains high ionic conductivity at ultralow temperatures(≤−30℃),enabling the FZHSC cycled well,and powering electronic timer robustly within an all-climate temperature range of−30~80℃.This work highlights that the promising Zn metal-free aqueous ZHSCs can be designed with great multifunctionality for more practical application scenarios.

A gel polymer electrolyte with IL@UiO-66-NH_(2) as fillers for high-performance all-solid-state lithium metal batteries

All solid-state electrolytes have the advantages of good mechanical and thermal properties for safer energy storage,but their energy density has been limited by low ionic conductivity and large interfacial resistance caused by the poor Li~+transport kinetics due to the solid-solid contacts between the electrodes and the solid-state electrolytes.Herein,a novel gel polymer electrolyte(UPP-5)composed of ionic liquid incorporated metal-organic frameworks nanoparticles(IL@MOFs)is designed,it exhibits satisfying electrochemical performances,consisting of an excellent electrochemical stability window(5.5 V)and an improved Li^(+)transference number of 0.52.Moreover,the Li/UPP-5/LiFePO_(4) full cells present an ultra-stable cycling performance at 0.2C for over 100 cycles almost without any decay in capacities.This study might provide new insight to create an effective Li^(+)conductive network for the development of all-solid-state lithium-ion batteries.

Amine-functionalized mesoporous UiO-66 aerogel for CO_(2) adsorption

A mesoporous UiO-66-NH_(2) aerogel is prepared via a straightforward sol-gel method without using any binders or mechanical pressures, in which the amine groups are directly introduced into the matrix by using 2-aminoterephthalic acid. The novel UiO-66-NH_(2) aerogel also exhibits high specific surface area and mesopore-dominated structure, implying its highly potential use in CO_(2) adsorption. For ulteriorly investigating the effect of amine loading on the CO_(2) adsorption ability, a series of UiO-66-NH_(2) aerogel with different amino content is fabricated by changing the ligand/metal molar ratio. When the molar ratio is 1.45, the CO_(2) adsorption capacity reaches the optimum value of 2.13 mmol·g^(-1) at 25 ℃ and 0.1 MPa, which is 12.2% higher than that of pure UiO-66 aerogel. Additionally, UiO-66-NH_(2)-1.45 aerogel also has noticeable CO_(2) selectivity against N_(2) and CH_(4) as well as good regeneration stability. Such results imply that it has good application prospect in the field of CO_(2) adsorption, and also contains the potential to be applied in catalysis, separation and other fields.

Effect of Bismuth Subgallate/Borneol Combined with Autologous Platelet-Rich Gel in the Treatment of Patients with Diabetic Foot Ulcers

Objective: To explore the effect of Bismuth Subgallate/Borneol (SuileTM BSB) healing dressing combined with autologous platelet-rich gel (APG) in the treatment of diabetic foot ulcer (DFU). Methods: A total of 120 patients with DFU hospitalized in the Changsha Central Hospital from August 2020 to September 2021 were selected and randomly divided into an experimental group (BSB + APG, n = 60) and a control group (BSB, n = 60) according to random number table method. The total therapeutic effect, healing time, hospital stay, level indexes of various inflammatory factors before and after treatment and ulcer area were observed in the two groups. Results: The total effect of the control group was worse than that of the experimental group, and the data between the two groups were significant (P 0.05);after treatment, the levels of inflammatory factors including WBC, CRP, IL-6 and TNF-α in the control group were higher than those in the experimental group, and there was significant difference between the two groups (P 0.05);after 14 days of treatment, the ulcer area in the control group was larger than that in the experimental group, and the data between the two groups were significant (P Conclusion: BSB combined with APG can achieve better therapeutic effect, reduce the inflammatory reaction of patients, and promote wound healing in the treatment of patients with diabetic foot ulcer.

Aluminum phosphate gel reduces early rebleeding in cirrhotic patients with gastric variceal bleeding treated with histoacryl injection therapy

BACKGROUND Esophageal-gastro varices bleeding(EGVB)is the most widely known cause of mortality in individuals with cirrhosis,with an occurrence rate of 5%to 15%.Among them,gastric varices bleeding(GVB)is less frequent than esophageal varices bleeding(EVB),but the former is a more critical illness and has a higher mortality rate.At present,endoscopic variceal histoacryl injection therapy(EVHT)is safe and effective,and it has been recommended by relevant guidelines as the primary method for the treatment of GVB.However,gastric varices after endoscopic treatment still have a high rate of early rebleeding,which is mainly related to complications of its treatment,such as bleeding from drained ulcers,rebleeding of varices etc.Therefore,preventing early postoperative rebleeding is very important to improve the quality of patient survival and outcomes.AIM To assess the efficacy of aluminium phosphate gel(APG)combined with proton pump inhibitor(PPI)in preventing early rebleeding after EVHT in individuals with GVB.METHODS Medical history of 196 individuals with GVB was obtained who were diagnosed using endoscopy and treated with EVHT in Shenzhen People's Hospital from January 2016 to December 2021.Based on the selection criteria,101 patients were sorted into the PPI alone treatment group,and 95 patients were sorted into the PPI combined with the APG treatment group.The incidences of early rebleeding and corresponding complications within 6 wk after treatment were compared between both groups.Statistical methods were performed by two-sample t-test,Wilcoxon rank sum test andχ2 test.RESULTS No major variations were noted between the individuals of the two groups in terms of age,gender,Model for End-Stage Liver Disease score,coagulation function,serum albumin,hemoglobin,type of gastric varices,the dose of tissue glue injection and EV that needed to be treated simultaneously.The early rebleeding rate in PPI+APG group was 3.16%(3/95),which was much lower than that in the PPI group(12.87%,13/101)(P=0.013).Causes of early rebleeding:the incidence of gastric ulcer bleeding in the PPI+APG group was 2.11%(2/95),which was reduced in comparison to that in the PPI group(11.88%,12/101)(P=0.008);the incidence of venous bleeding in PPI+APG group and PPI group was 1.05%(1/95)and 0.99%(1/101),respectively,and there was no significant difference between them(0.999).The early mortality rate was 0 in both groups within 6 wk after the operation,and the low mortality rate was related to the timely hospitalization and active treatment of all patients with rebleeding.The overall incidence of complications in the PPI+APG group was 12.63%(12/95),which was not significantly different from 13.86%(14/101)in the PPI group(P=0.800).of abdominal pain in the PPI+APG group was 3.16%(3/95),which was lower than that in the PPI group(11.88%,12/101)(P=0.022).However,due to aluminum phosphate gel usage,the incidence of constipation in the PPI+APG group was 9.47%(9/95),which was higher than that in the PPI group(1.98%,2/101)(P=0.023),but the health of the patients could be improved by increasing drinking water or oral lactulose.No patients in either group developed spontaneous peritonitis after taking PPI,and none developed hepatic encephalopathy and ectopic embolism within 6 wk of EVHT treatment.CONCLUSION PPI combined with APG can significantly reduce the incidence of early rebleeding and postoperative abdominal pain in cirrhotic patients with GVB after taking EVHT.

Effect of nano TiO_(2) and SiO_(2) on gelation performance of HPAM/PEI gels for high-temperature reservoir conformance improvement

Nanoparticles have been widely used in polymer gel systems in recent years to improve gelation performance under high-temperature reservoir conditions. However, different types of nanoparticles have different effects on their gelation performance, which has been little researched. In this study, the high-temperature gelation performance, chemical structure, and microstructure of polymer gels prepared from two nanomaterials (i.e., nano-SiO_(2) and nano-TiO_(2)) were measured. The conventional HPAM/PEI polymer gel system was employed as the control sample. Results showed that the addition of nano-TiO_(2) could significantly enhance the gel strength of HPAM/PEI gel at 80 ℃. The gel strength of the enhanced HPAM/PEI gel with 0.1 wt% nano-TiO_(2) could reach grade I. The system also had excellent high-temperature stability at 150 ℃. The enhanced HPAM/PEI gel with 0.02 wt% nano-TiO_(2) reached the maximum gel strength at 150 ℃ with a storage modulus (G′) of 15 Pa, which can meet the need for efficient plugging. However, the nano-SiO_(2) enhanced HPAM/PEI polymer gel system showed weaker gel strength than that with nano-TiO_(2) at both 80 and 150 ℃ with G′ lower than 5 Pa. Microstructures showed that the nano-TiO_(2) enhanced HPAM/PEI gel had denser three-dimensional (3D) mesh structures, which makes the nano-TiO_(2) enhanced HPAM/PEI gel more firmly bound to water. The FT-IR results also confirmed that the chemical structure of the nano-TiO_(2) enhanced HPAM/PEI gel was more thermally stable than nano-SiO_(2) since there was a large amount of –OH groups on the structure surface. Therefore, nano-TiO_(2) was more suitable as the reinforcing material for HPAM/PEI gels for high-temperature petroleum reservoir conformance improvement.