Blends of polyacrylamide—PAM, poly(N-isopropylacrylamide)—PNIPAAm, poly(N-tert-butylacrylamide)—PTBAA, poly(N,N-dimethylacrylamide)—PDMAA and poly(N,N-diethylacrylamide)—PDEAA with poly(ethylene glycol)— PEG wer...Blends of polyacrylamide—PAM, poly(N-isopropylacrylamide)—PNIPAAm, poly(N-tert-butylacrylamide)—PTBAA, poly(N,N-dimethylacrylamide)—PDMAA and poly(N,N-diethylacrylamide)—PDEAA with poly(ethylene glycol)— PEG were prepared by casting in methanol and water at concentrations of 20 wt%, 40 wt%, 60 wt%, and 80 wt% in PEG. The miscibility of the components was studied by Differential Scanning Calorimetry—DSC. All blend systems are characterized by a single glass transition temperature (Tg), close to the Tg of the amorphous component. The Hoffman Weeks method was used to determine equilibrium melting temperature (Tm) data. The determination of the melt point depression of the blends allowed the calculation of Flory-Huggins interaction parameter (χ12) of the two polymers in the melt, by using the Nishi Wang equation. The interaction parameters, calculated for all the blends, are slightly negative and close to zero, suggesting a partial miscibility between the components.展开更多
Surfactant-grafted Polyacrylamide (S-PAM), as a new type of oil displacement agent in oilfield, integrates the advantages of both polymer and surfactant. The oil displacement experiments using S-PAM in multi-blocks re...Surfactant-grafted Polyacrylamide (S-PAM), as a new type of oil displacement agent in oilfield, integrates the advantages of both polymer and surfactant. The oil displacement experiments using S-PAM in multi-blocks reveal that in-use S-PAMs differ greatly from ordinary polymers and the physical properties remain unclear. This is unfavorable to production application and occupational health and safety. This research compared the physical properties of S-PAMs selected from two producing area, including specific gravity, particle size and viscosity. The compared results showed that specific gravity of Lianhua S-PAM was smaller than Haibo S-PAM;Lianhua S-PAM and Haibo S-PAM accounted for the 93.8% and 80.1% of the total amount via the particles with 40 mesh and 60 mesh;the viscosity of Lianhua S-PAM was higher than that of Haibo S-PAM in two S-PAM solutions with different concentrations.展开更多
Merging the characteristics of thermoresponsive and stimuli-degradable polymers yields so-called transiently thermoresponsive polymers, which can find application for the design of injectable gels, nanoparticles, etc....Merging the characteristics of thermoresponsive and stimuli-degradable polymers yields so-called transiently thermoresponsive polymers, which can find application for the design of injectable gels, nanoparticles, etc. within a biomedical context. Among these polymers, only a limited number is reported which shows selective degradation under mild acidic conditions. However,extension of the library of transiently thermoresponsive polymers is desired to broadening the biomaterials toolbox to suit specific needs. Three monomers were developed by modification of 2-hydroxyethylacrylamide(HEAm) via tetrahydropyranylation or-furanylation with 3,4-dihydro-2 H-pyran(DHP), 2,3-dihydrofuran(DHF) or 2,3-dihydro-5-methylfuran(MeDHF). The presence of an acetal or ketal bond provided the monomers a pH-dependent hydrolysis behavior ranging from minutes to days. RAFT polymerisation allowed for the construction of homopolymers with temperature responsive behavior and pH-dependent hydrolysis which was strongly influenced by nature of the monomeric repeating units.展开更多
With the wide application of electromagnetic wave,a high performance electromagnetic shielding material is urgently needed to solve the harm caused by electromagnetic wave.Complete cross-linking strategy is adopted in...With the wide application of electromagnetic wave,a high performance electromagnetic shielding material is urgently needed to solve the harm caused by electromagnetic wave.Complete cross-linking strategy is adopted in this paper.Polyacrylamide(PAM)was synthesized by in-situ polymerization of acrylamide(AM)monomer.The obtained PAM was blended with polyethylene glycol(PEG)to prepare PAM/PEG hydrogels and form rigid support structures.Subsequently,the modified carbon nanotubes(S-CNTs)were incorpor-ated into sodium alginate(SA)and PAM/PEG.Finally,Na+was used to trigger SA self-assembly,which significantly improved the mechanical properties and electrical conductivity of the hydrogels,and prepared PAM/PEG/SA/S-CNTs-Na hydrogels with high tough-ness and strong electromagnetic interference(EMI)shielding efficiency(SE).The results showed that the compressive strength of PAM/PEG/SA/S-CNTs-Na hydrogel was 19.05 MPa,which was 7.69%higher than that of PAM/PEG hydrogel(17.69 MPa).More en-couraging,the average EMI SE of PAM/PEG/SA/S-CNTs-Na hydrogels at a thickness of only 3 mm and a CNTs content of 16.53wt%was 32.92 dB,which is 113.21%higher than that of PAM/PEG hydrogels(15.44 dB).展开更多
Neuronal growth, extension, branching, and formation of neural networks are markedly influenced by the extracellular matrix—a complex network composed of proteins and carbohydrates secreted by cells. In addition to p...Neuronal growth, extension, branching, and formation of neural networks are markedly influenced by the extracellular matrix—a complex network composed of proteins and carbohydrates secreted by cells. In addition to providing physical support for cells, the extracellular matrix also conveys critical mechanical stiffness cues. During the development of the nervous system, extracellular matrix stiffness plays a central role in guiding neuronal growth, particularly in the context of axonal extension, which is crucial for the formation of neural networks. In neural tissue engineering, manipulation of biomaterial stiffness is a promising strategy to provide a permissive environment for the repair and regeneration of injured nervous tissue. Recent research has fine-tuned synthetic biomaterials to fabricate scaffolds that closely replicate the stiffness profiles observed in the nervous system. In this review, we highlight the molecular mechanisms by which extracellular matrix stiffness regulates axonal growth and regeneration. We highlight the progress made in the development of stiffness-tunable biomaterials to emulate in vivo extracellular matrix environments, with an emphasis on their application in neural repair and regeneration, along with a discussion of the current limitations and future prospects. The exploration and optimization of the stiffness-tunable biomaterials has the potential to markedly advance the development of neural tissue engineering.展开更多
The traditional cement-based stabilization cannot effectively stabilize the marine soft clay under submerged conditions.In order to solve this problem,the enhancement of cement-stabilized marine soft clay was investig...The traditional cement-based stabilization cannot effectively stabilize the marine soft clay under submerged conditions.In order to solve this problem,the enhancement of cement-stabilized marine soft clay was investigated in this study by adding the ionic soil stabilizer(ISS)and polyacrylamide(PAM).For this purpose,varying contents of ISS and PAM(ISS-P)were added into cement-stabilized marine soft clay and subjected to curing under submerged conditions.Atterberg limits tests,direct shear tests,unconfined compression strength(UCS)tests,water-stability tests,scanning electron microscopy analysis,and X-ray diffraction analysis were carried out.The results show that using 1.8%ISS and 0.9%PAM as the optimal ratio,the cohesion,internal friction angle,UCS,and water-stability of the samples increased by 182.7%,15.4%,176.5%,and 368.5% compared to the cement-stabilized soft clay after 28 d.The increment in soil cohesion with increasing ISS-P content was more apparent than that in the internal friction angle.The combined action of ion exchange attraction and electrostatic adsorption altered the failure characteristics of the samples,resulting in localized micro-cracking and multiple failure paths.Increasing the content of ISS-P strengthened the skeletal structure of soil,reduced inter-particle spacing,and enhanced the water-stability.Additionally,ISS promotes the hydration of cement and compensates for the inhibitory effect of PAM on early cement hydration.ISS-P can effectively enhance the strength and stability of submerged cement-based stabilized marine soft clay.展开更多
Polymer flooding is a widely used technique in enhanced oil recovery (EOR),but its effectiveness is often hindered by the poor viscosity retention of conventional polymers like hydrolyzed polyacrylamide (HPAM) under h...Polymer flooding is a widely used technique in enhanced oil recovery (EOR),but its effectiveness is often hindered by the poor viscosity retention of conventional polymers like hydrolyzed polyacrylamide (HPAM) under high-salinity conditions.Although recent advances in molecular engineering have concentrated on modifying polymer architecture and functional groups to address this issue,the complex interplay among polymer topology,charge distribution and hydrophilic-hydrophobic balance renders rational molecular design challenging.In this work,we present an AI-driven inverse design framework that directly maps target viscosity performance back to optimal molecular structures.Guided by practical molecular design strategies,the topological features (grafting density,side-chain length) and functional group-related features(copolymerization ratio,hydrophilic-hydrophobic balance) are encoded into a multidimensional design space.By integrating dissipative particle dynamics simulations with particle swarm algorithm,the framework efficiently explores the design space and identifies non-intuitive,high-performing polymer structure.The optimized polymer achieves a 12%enhancement in viscosity,attributed to the synergistic effect of electrostatic chain extension and hydrophobic aggregation.This study demonstrates the promise of AI-guided inverse design for developing next-generation EOR polymers and provides a generalizable approach for the discovery of functional soft materials.展开更多
A series of amine-bridged bis(phenolate)rare-earth(Sc,Y)aryloxides was synthesized and characterized.These complexes were successfully used for the controlled Lewis pair polymerization(LPP)of functional acrylamides in...A series of amine-bridged bis(phenolate)rare-earth(Sc,Y)aryloxides was synthesized and characterized.These complexes were successfully used for the controlled Lewis pair polymerization(LPP)of functional acrylamides in combination with phosphines,affording a new type of polyacrylamides with predictable molecular weight and low molecular weight distribution.The living nature of this LPP was verified by near-quantitative initiation efficiencies,a linear increase of molecular weight vs monomer-to-initiator ratio and monomer conversion,chain extensions,and the synthesis of well-defined block copolymers.The mechanistic studies were performed through the isolation of a zwitterionic intermediate as well as the end-chain analysis of oligomers,showcasing a rare-earth/phosphine cooperation.Furthermore,the resultant polyacrylamides exhibit outstanding thermal stability and great potential for application in photovoltaic devices.展开更多
With the widespread popularity of electronic equipment and rapid development of wireless communication technology,electromagnetic shielding materials possessing thermal insulation properties can effectively block elec...With the widespread popularity of electronic equipment and rapid development of wireless communication technology,electromagnetic shielding materials possessing thermal insulation properties can effectively block electromagnetic radiation for ensuring normal operation of electronic equipment and human health,while providing heat insulation to improve energy efficiency and protect equipment from high temperatures.In this study,we employ covalent organic skeleton(COF)to optimize Ti_(3)C_(2)T_(x)MXene layers and successfully prepare MXene@COF heterostructures.This structure maintained the unique two-dimensional architecture of Ti_(3)C_(2)T_(x)MXene while preventing aggregation and self-stacking of MXene nanosheets through the outer COF layer.The modification increases material porosity and significantly enhances electrical conductivity.We incorporated the heterostructure into acrylamidegelatin hydrogels and controlled shielding efficiency by varying COF content.Results demonstrate that the MXene@COF-based hydrogel(15 mm p-pheny lenedi amine)exhibits high toughness,strong electromagnetic shielding capability,infrared stealth performance,and thermal insulation properties.In the X-band,mechanical tests show only 3 mm in thickness and 0.90 wt%MXene@COF content,electromagnetic shielding efficiency(EMI SE)of the material is as high as 37.52 dB,and the average total electromagnetic shielding(SE_(T))is 32.01 dB,the compressive stress is 20.85 MPa,the water content is 79.04%,and the electrical conductivity is 1.22 S m^(-1).These finding soffer new possibilities for developing COF-based electromagnetic shielding materials.展开更多
Proteomics is one of the most active research fields in the post-genomic era. Here we briefly introduce the scientific background of the origination of proteomics and its content, research method. The new developments...Proteomics is one of the most active research fields in the post-genomic era. Here we briefly introduce the scientific background of the origination of proteomics and its content, research method. The new developments of proteomics at the levels of individual plants, tissues, organs and organells, as well as its applications in the area of plant genetic diversity, mutant characterization, and plant physiology, etc are reviewed. At last, the challenge and prospect of proteomics are discussed.展开更多
Polyacrylamide gel electrophoresis (PAGE) and biochemical staining method were used in this study for the analysis on malate dehydrogenase (MDH,E.C. 1.1.1.37) isozymes zymogram in 11 different types of tissues of male...Polyacrylamide gel electrophoresis (PAGE) and biochemical staining method were used in this study for the analysis on malate dehydrogenase (MDH,E.C. 1.1.1.37) isozymes zymogram in 11 different types of tissues of male and female Varicorhinus macrolepis. It had been found for the first time that the phenotype of malate dehydrogenase (MDH),acid phosphatase (ACP) and superoxide dismutase (SOD) showed difference between male and female V. macrolepis,and there was no difference among different individuals in the same sex. Therefore,the electrophoresis band of malate dehydrogenase,acid phosphatase and superoxide dismutase could be used as an indicator for the identification of gender and tissues of V. macrolepis,which would provide basic data for the developmental genetics,variety improvement and directed breeding of V. macrolepis groups,thus facilitating the development and protection of this valuable fish species.展开更多
[Objective]The research aimed to provide scientific reference for reasonable utilization of polyacrylamide(PAM).[Method]After PAM treatment,the soil aggregates were classified through dry sieve analysis and the adsorp...[Objective]The research aimed to provide scientific reference for reasonable utilization of polyacrylamide(PAM).[Method]After PAM treatment,the soil aggregates were classified through dry sieve analysis and the adsorption capacity and desorption capacity of all soil aggregates to phosphorus at different phosphorus concentrations were analyzed.[Result] The phosphorus adsorption and desorption of soil sample treated by PAM declined. The amount of phosphorus adsorption increased with the increase of phosphorus concentration and this increase was fast in low phosphorus concentration area but slow in high phosphorus concentration area.At different phosphorus concentrations,adsorption showed a へ shape changing trend.The phosphorus adsorption was related to phosphorus concentration and the 2-3 mm aggregate had the highest desorption rate while 0.1-0.25 mm aggregate and 0.45-1 mm aggregate had lowest desorption rate.[Conclusion]The PAM treatment generated significant influence on phosphorus adsorption and analytic features of aggregate in all size fractions.展开更多
[Objective] The aim was to optimize the SSR-PCR non-denatured polyacrylamide gel electrophoresis conditions in kernelled apricot.[Method]25 accessions of kernelled apricot and three accessions of edible apricot were s...[Objective] The aim was to optimize the SSR-PCR non-denatured polyacrylamide gel electrophoresis conditions in kernelled apricot.[Method]25 accessions of kernelled apricot and three accessions of edible apricot were selected as experimental materials to screen the repeatable SSR loci with high polymorphism by the use of SSR markers combined with non-denatured polyacrylamide gel electrophoresis.And the effect of different factors on electrophoresis conditions was compared to explore the optimal SSR-PCR non-denatured polyacrylamide gel electrophoresis conditions in kernelled apricot.[Result]The optimal non-denatured polyacrylamide gel electrophoresis conditions for SSR-PCR were established as follows：polyacrylamide gel concentration 6%,the ratio of acrylamide to bisacrylamide 29∶1,electrophoresis at 1 000 V for 2-3 h,and staining for 15 min within 0.1% AgNO3.[Conclusion]The optimum electrophoresis system has provided some technical foundations to further study the phylogenetic relationship of kernelled apricots by SSR markers.展开更多
[Objective] The paper was to improve polyacrylamide gel electrophorus in Phytophthora infeatans SSR Marker.[Method] With the disease sample of P.infeatans collected from Guyuan in Ningxia Province in 2009 as test mate...[Objective] The paper was to improve polyacrylamide gel electrophorus in Phytophthora infeatans SSR Marker.[Method] With the disease sample of P.infeatans collected from Guyuan in Ningxia Province in 2009 as test material,its DNA was extracted and amplified with PCR,and its products were carried out polyacrylamide gel electrophoresis.[Result] 12% polyacrylamide gel electrophoresis was used to detect primers D13,G11 and PI02,and 8% polyacrylamide gel electrophoresis was used to detect primers PI4B,PI63,SSR4,SSR8 and SSR11,then 0.1% silver nitrate was used to stain,and an ideal electrophoresis and staining effect was obtained.[Conclusion] The electrophoresis and staining method suitable for P.infeatans SSR Marker established in the study had the characteristics of high sensitivity,simple operation and clear bands,which was an effective,simple and quick detection method.展开更多
Interaction of polymer-containing injected fluids with shale is a widely studied phenomenon, but much is still unknown about the interaction of charged polyacrylamides such as anionic and cationic polyacrylamides with...Interaction of polymer-containing injected fluids with shale is a widely studied phenomenon, but much is still unknown about the interaction of charged polyacrylamides such as anionic and cationic polyacrylamides with shale. The nature of interaction of charged polyacrylamides with shale is not well understood, especially from the perspective of assessing the potential for polyacrylamides to cause formation damage. Zeta potential and rheological measurements were made for Chattanooga and Pride Mountain shales suspended in polyacrylamide solutions with and without inorganic salts and tetramethyl ammonium chloride（TMAC）. The change in zeta potential and viscosity with time was recorded. The magnitude of decrease in the absolute value of zeta potential with time is indicative of adsorption of polymer on the surface of shale and serves as a measure of the extent of polymer interaction with shale. The salts that were used in this study are potassium chloride（KCl）, sodium chloride（Na Cl）. This study quantified the interaction of anionic and cationic polyacrylamide with different North American shales.From the experimental results, it was determined that the polyacrylamides can interact strongly with shale, particularly the cationic polyacrylamide. The objective of this study was to determine the extent of interaction of anionic and cationic polyacrylamide with each shale sample in the presence of additives such as salts.展开更多
Although inorganic phosphate is an essential plant nutrient, elevated levels in surface waters lead to adverse effects in the environment. These effects are attributed to runoff from rain or irrigation events that may...Although inorganic phosphate is an essential plant nutrient, elevated levels in surface waters lead to adverse effects in the environment. These effects are attributed to runoff from rain or irrigation events that may cause the sorbed phosphate to be transported from the application sites and to move into neighboring watersheds. Increased phosphate concentration in watersheds may lead to a variety of environmental problems including increased algal blooms, bacterial contamination, and in some cases eutrophication. To overcome these effects, polymer flocculants have been shown to reduce the phosphate concentration in water by removing suspended solids and thereby removing the phosphate sorbed to the solids. The purpose of this study is to determine the amount, if any, of phosphate removed by several commercial polymers. The polymers chosen include the polyacrylamides Magnifloc 494C, Magnifloc 985N and Poly (diallyldimethyl ammonium chloride) (Poly (DADMAC)). Using these polymers, it is discovered that the positive charge density of the polymers affects the amount of phosphate removed from solution with Poly (DADMAC) (having 100% positive charge density) removing 40% of the phosphate from a solution containing 10 ppm phosphate.展开更多
Partially hydrolyzed polyacrylamide （HPAM） has been widely used for water shut-off and profile control to enhance oil recovery. Herein, we reported a novel technique by which the crosslinking between HPAM and Cr3＋ ...Partially hydrolyzed polyacrylamide （HPAM） has been widely used for water shut-off and profile control to enhance oil recovery. Herein, we reported a novel technique by which the crosslinking between HPAM and Cr3＋ in aqueous solutions at 60 ℃ can be delayed effectively. Citric acid was selected as an organic complexing agent of Cr3＋ so that the crosslinking between HPAM and Cr3＋ can be prevented completely. Due to the decomposi- tion of the bicarbonate （HCO3-） embedded in solution, CO2 released from solution and the pH value of solution increased gradually. The degree of ionization of HPAM and its ability to complex with Cr3＋ increased accordingly. When the complexation of Cr3＋ with HPAM is stronger than that with citric acid, the viscosity of the HPAM solution increased signif- icantly. Under the closed condition, together with the existence of potassium dihydrogen phosphate （KH2PO4）, the release of CO2 was very slow and the condition was highly con- trolled so that the ionization of HPAM was prevented initially. Furthermore, the hydrogen bonding interactions between HPAM and melamine embedded in solution previously also postponed the ionization of HPAM. As a result, the crosslinking between HPAM and Cr3＋ can be delayed for almost one month, completely meeting the requirements for deep water shut-off and profile control to enhance oil recovery.展开更多
All of the Rho GTPase seems to form a special sub-family,because such a sub-family has so far only found in plants,and then named Rop GTPase,which directly involved in and regulated of muscle actin cytoskeletal reorga...All of the Rho GTPase seems to form a special sub-family,because such a sub-family has so far only found in plants,and then named Rop GTPase,which directly involved in and regulated of muscle actin cytoskeletal reorganization,such as a series of signal transductions.The efficient purification technology and the means of ROP GTPase in wheat are the key basis of the studies on its functions and prosperities.And it has a very important theoretical and practical significance in the signal transduction and F-act...展开更多
Produced water from polymer flooding is difficult to treat due to its high polymer concentration,high viscosity,and emulsified characteristics.The dithiocarbamate flocculant,DTC(T403),was prepared by the amine-termina...Produced water from polymer flooding is difficult to treat due to its high polymer concentration,high viscosity,and emulsified characteristics.The dithiocarbamate flocculant,DTC(T403),was prepared by the amine-terminated polyoxypropane-effier compound known as Jeffamine-T403.The product was characterized by IR spectra and elemental analysis.The DTC agent chelating with Fe2+produced a network polymer matrix,which captured and removed oil droplets efficiently.Oil removal by the flocculent on simulated produced water with 0,200,500,900 mg/L of partially hydrolyzed polyacrylamide(HPAM)was investigated for aspects of effectiveness of DTC(T403)dosage and concentrations of HPAM and Fe2+ions in the wastewater.Results showed that HPAM had a negative influence on oil removal efficiency when DTC(T403)dosage was lower than 20 mg/L.However,residual oil concentrations in tested samples with different concentrations of HPAM all decreased below 10 mg/L when DTC(T403)dosage reached 30 mg/L.The concentration of Fe2+in the initial wastewater had a slight effect on oil removal at the range of 2-12 mg/L.Results showed that Fe3+could not be used in place of Fe2+as Fe3+could not react with DTC under flocculated conditions.The effects of mineral salts ions were also investigated.展开更多
基金the Brazilian Agencies CNPq,CAPES and FAPEMIG for financial support.
文摘Blends of polyacrylamide—PAM, poly(N-isopropylacrylamide)—PNIPAAm, poly(N-tert-butylacrylamide)—PTBAA, poly(N,N-dimethylacrylamide)—PDMAA and poly(N,N-diethylacrylamide)—PDEAA with poly(ethylene glycol)— PEG were prepared by casting in methanol and water at concentrations of 20 wt%, 40 wt%, 60 wt%, and 80 wt% in PEG. The miscibility of the components was studied by Differential Scanning Calorimetry—DSC. All blend systems are characterized by a single glass transition temperature (Tg), close to the Tg of the amorphous component. The Hoffman Weeks method was used to determine equilibrium melting temperature (Tm) data. The determination of the melt point depression of the blends allowed the calculation of Flory-Huggins interaction parameter (χ12) of the two polymers in the melt, by using the Nishi Wang equation. The interaction parameters, calculated for all the blends, are slightly negative and close to zero, suggesting a partial miscibility between the components.
文摘Surfactant-grafted Polyacrylamide (S-PAM), as a new type of oil displacement agent in oilfield, integrates the advantages of both polymer and surfactant. The oil displacement experiments using S-PAM in multi-blocks reveal that in-use S-PAMs differ greatly from ordinary polymers and the physical properties remain unclear. This is unfavorable to production application and occupational health and safety. This research compared the physical properties of S-PAMs selected from two producing area, including specific gravity, particle size and viscosity. The compared results showed that specific gravity of Lianhua S-PAM was smaller than Haibo S-PAM;Lianhua S-PAM and Haibo S-PAM accounted for the 93.8% and 80.1% of the total amount via the particles with 40 mesh and 60 mesh;the viscosity of Lianhua S-PAM was higher than that of Haibo S-PAM in two S-PAM solutions with different concentrations.
基金supported by Ghent University through the BOF-GOA grant scheme.
文摘Merging the characteristics of thermoresponsive and stimuli-degradable polymers yields so-called transiently thermoresponsive polymers, which can find application for the design of injectable gels, nanoparticles, etc. within a biomedical context. Among these polymers, only a limited number is reported which shows selective degradation under mild acidic conditions. However,extension of the library of transiently thermoresponsive polymers is desired to broadening the biomaterials toolbox to suit specific needs. Three monomers were developed by modification of 2-hydroxyethylacrylamide(HEAm) via tetrahydropyranylation or-furanylation with 3,4-dihydro-2 H-pyran(DHP), 2,3-dihydrofuran(DHF) or 2,3-dihydro-5-methylfuran(MeDHF). The presence of an acetal or ketal bond provided the monomers a pH-dependent hydrolysis behavior ranging from minutes to days. RAFT polymerisation allowed for the construction of homopolymers with temperature responsive behavior and pH-dependent hydrolysis which was strongly influenced by nature of the monomeric repeating units.
基金supported by the National Natural Science Foundation of China(No.52163001)the Guizhou Provincial Science and Technology Program Project Grant,China(Qiankehe Platform Talents-CXTD[2021]005,Qiankehe Platform Talents-GCC[2022]010-1,Qiankehe Fuqi[2023]001,Qiankehe Platform Talents-GCC[2023]035,and Qiankehe Platform Talents-CXTD[2023]003)+3 种基金the Guizhou Minzu University Research Platform Grant,China(No.GZMUGCZX[2021]01)the Central Guided Local Science and Technology Development Funds Project,China(Qiankehe Zhong Yindi[2023]035)the Green Chemistry and Resource Environment Innovation Team of Guizhou Higher Education Institutions,China(Guizhou Education and Technology[2022]No.13)the Doctor Startup Fund of Guizhou Minzu University,China(No.GZMUZK[2024]QD77).
文摘With the wide application of electromagnetic wave,a high performance electromagnetic shielding material is urgently needed to solve the harm caused by electromagnetic wave.Complete cross-linking strategy is adopted in this paper.Polyacrylamide(PAM)was synthesized by in-situ polymerization of acrylamide(AM)monomer.The obtained PAM was blended with polyethylene glycol(PEG)to prepare PAM/PEG hydrogels and form rigid support structures.Subsequently,the modified carbon nanotubes(S-CNTs)were incorpor-ated into sodium alginate(SA)and PAM/PEG.Finally,Na+was used to trigger SA self-assembly,which significantly improved the mechanical properties and electrical conductivity of the hydrogels,and prepared PAM/PEG/SA/S-CNTs-Na hydrogels with high tough-ness and strong electromagnetic interference(EMI)shielding efficiency(SE).The results showed that the compressive strength of PAM/PEG/SA/S-CNTs-Na hydrogel was 19.05 MPa,which was 7.69%higher than that of PAM/PEG hydrogel(17.69 MPa).More en-couraging,the average EMI SE of PAM/PEG/SA/S-CNTs-Na hydrogels at a thickness of only 3 mm and a CNTs content of 16.53wt%was 32.92 dB,which is 113.21%higher than that of PAM/PEG hydrogels(15.44 dB).
基金supported by the Natio`nal Natural Science Foundation of China,No. 81801241a grant from Sichuan Science and Technology Program,No. 2023NSFSC1578Scientific Research Projects of Southwest Medical University,No. 2022ZD002 (all to JX)。
文摘Neuronal growth, extension, branching, and formation of neural networks are markedly influenced by the extracellular matrix—a complex network composed of proteins and carbohydrates secreted by cells. In addition to providing physical support for cells, the extracellular matrix also conveys critical mechanical stiffness cues. During the development of the nervous system, extracellular matrix stiffness plays a central role in guiding neuronal growth, particularly in the context of axonal extension, which is crucial for the formation of neural networks. In neural tissue engineering, manipulation of biomaterial stiffness is a promising strategy to provide a permissive environment for the repair and regeneration of injured nervous tissue. Recent research has fine-tuned synthetic biomaterials to fabricate scaffolds that closely replicate the stiffness profiles observed in the nervous system. In this review, we highlight the molecular mechanisms by which extracellular matrix stiffness regulates axonal growth and regeneration. We highlight the progress made in the development of stiffness-tunable biomaterials to emulate in vivo extracellular matrix environments, with an emphasis on their application in neural repair and regeneration, along with a discussion of the current limitations and future prospects. The exploration and optimization of the stiffness-tunable biomaterials has the potential to markedly advance the development of neural tissue engineering.
基金supported by the Fundamental Research Funds for the Central Universities(Nos.202061027,202261063)the National Natural Science Foundation of China(No.41572247)。
文摘The traditional cement-based stabilization cannot effectively stabilize the marine soft clay under submerged conditions.In order to solve this problem,the enhancement of cement-stabilized marine soft clay was investigated in this study by adding the ionic soil stabilizer(ISS)and polyacrylamide(PAM).For this purpose,varying contents of ISS and PAM(ISS-P)were added into cement-stabilized marine soft clay and subjected to curing under submerged conditions.Atterberg limits tests,direct shear tests,unconfined compression strength(UCS)tests,water-stability tests,scanning electron microscopy analysis,and X-ray diffraction analysis were carried out.The results show that using 1.8%ISS and 0.9%PAM as the optimal ratio,the cohesion,internal friction angle,UCS,and water-stability of the samples increased by 182.7%,15.4%,176.5%,and 368.5% compared to the cement-stabilized soft clay after 28 d.The increment in soil cohesion with increasing ISS-P content was more apparent than that in the internal friction angle.The combined action of ion exchange attraction and electrostatic adsorption altered the failure characteristics of the samples,resulting in localized micro-cracking and multiple failure paths.Increasing the content of ISS-P strengthened the skeletal structure of soil,reduced inter-particle spacing,and enhanced the water-stability.Additionally,ISS promotes the hydration of cement and compensates for the inhibitory effect of PAM on early cement hydration.ISS-P can effectively enhance the strength and stability of submerged cement-based stabilized marine soft clay.
基金supported by the Key Technologies R&D Program of China National Offshore Oil Corporation(No.KJGG2021-0504).
文摘Polymer flooding is a widely used technique in enhanced oil recovery (EOR),but its effectiveness is often hindered by the poor viscosity retention of conventional polymers like hydrolyzed polyacrylamide (HPAM) under high-salinity conditions.Although recent advances in molecular engineering have concentrated on modifying polymer architecture and functional groups to address this issue,the complex interplay among polymer topology,charge distribution and hydrophilic-hydrophobic balance renders rational molecular design challenging.In this work,we present an AI-driven inverse design framework that directly maps target viscosity performance back to optimal molecular structures.Guided by practical molecular design strategies,the topological features (grafting density,side-chain length) and functional group-related features(copolymerization ratio,hydrophilic-hydrophobic balance) are encoded into a multidimensional design space.By integrating dissipative particle dynamics simulations with particle swarm algorithm,the framework efficiently explores the design space and identifies non-intuitive,high-performing polymer structure.The optimized polymer achieves a 12%enhancement in viscosity,attributed to the synergistic effect of electrostatic chain extension and hydrophobic aggregation.This study demonstrates the promise of AI-guided inverse design for developing next-generation EOR polymers and provides a generalizable approach for the discovery of functional soft materials.
基金supported by National Natural Science Foundation of China(21871204,22371198)Postgraduate Research&Practice Innovation Program of Jiangsu Province。
文摘A series of amine-bridged bis(phenolate)rare-earth(Sc,Y)aryloxides was synthesized and characterized.These complexes were successfully used for the controlled Lewis pair polymerization(LPP)of functional acrylamides in combination with phosphines,affording a new type of polyacrylamides with predictable molecular weight and low molecular weight distribution.The living nature of this LPP was verified by near-quantitative initiation efficiencies,a linear increase of molecular weight vs monomer-to-initiator ratio and monomer conversion,chain extensions,and the synthesis of well-defined block copolymers.The mechanistic studies were performed through the isolation of a zwitterionic intermediate as well as the end-chain analysis of oligomers,showcasing a rare-earth/phosphine cooperation.Furthermore,the resultant polyacrylamides exhibit outstanding thermal stability and great potential for application in photovoltaic devices.
基金financially supported by the National Natural Science Foundation of China(No.52163001)Guizhou Provincial Science and Technology Program Project(Nos.Qiankehe Platform Talents-CXTD[2021]005,Qiankehe Platform Talents-GCC[2022]010-1,Qiankehe Platform TalentsGCC[2023]035,Qiankehe Platform Talents-CXTD[2023]003 and Qiankehe Platform Talents-KXJZ[2024]022)+3 种基金Guizhou Minzu University Research Platform(No.GZMUGCZX[2021]01)the Central Guided Local Science and Technology Development Funds Project(No.Qiankehe Zhong Yindi[2023]035)the Doctor Startup Fund of Guizhou Minzu University(No.GZMUZK[2024]QD77)Guizhou Province Special Fund for innovative capacity building of scientific research institutions(Nos.Qiankehe Fuqi[2023]001 and Qiankehe Fuqi[2024]002-1)
文摘With the widespread popularity of electronic equipment and rapid development of wireless communication technology,electromagnetic shielding materials possessing thermal insulation properties can effectively block electromagnetic radiation for ensuring normal operation of electronic equipment and human health,while providing heat insulation to improve energy efficiency and protect equipment from high temperatures.In this study,we employ covalent organic skeleton(COF)to optimize Ti_(3)C_(2)T_(x)MXene layers and successfully prepare MXene@COF heterostructures.This structure maintained the unique two-dimensional architecture of Ti_(3)C_(2)T_(x)MXene while preventing aggregation and self-stacking of MXene nanosheets through the outer COF layer.The modification increases material porosity and significantly enhances electrical conductivity.We incorporated the heterostructure into acrylamidegelatin hydrogels and controlled shielding efficiency by varying COF content.Results demonstrate that the MXene@COF-based hydrogel(15 mm p-pheny lenedi amine)exhibits high toughness,strong electromagnetic shielding capability,infrared stealth performance,and thermal insulation properties.In the X-band,mechanical tests show only 3 mm in thickness and 0.90 wt%MXene@COF content,electromagnetic shielding efficiency(EMI SE)of the material is as high as 37.52 dB,and the average total electromagnetic shielding(SE_(T))is 32.01 dB,the compressive stress is 20.85 MPa,the water content is 79.04%,and the electrical conductivity is 1.22 S m^(-1).These finding soffer new possibilities for developing COF-based electromagnetic shielding materials.
文摘Proteomics is one of the most active research fields in the post-genomic era. Here we briefly introduce the scientific background of the origination of proteomics and its content, research method. The new developments of proteomics at the levels of individual plants, tissues, organs and organells, as well as its applications in the area of plant genetic diversity, mutant characterization, and plant physiology, etc are reviewed. At last, the challenge and prospect of proteomics are discussed.
基金Supported by National Natural Science Foundation of China(30700071 )Natural Science Foundation of Shandong Province(Y2008D03 )Science and Technology Program of Qingdao City(08-1-27-jch)~~
文摘Polyacrylamide gel electrophoresis (PAGE) and biochemical staining method were used in this study for the analysis on malate dehydrogenase (MDH,E.C. 1.1.1.37) isozymes zymogram in 11 different types of tissues of male and female Varicorhinus macrolepis. It had been found for the first time that the phenotype of malate dehydrogenase (MDH),acid phosphatase (ACP) and superoxide dismutase (SOD) showed difference between male and female V. macrolepis,and there was no difference among different individuals in the same sex. Therefore,the electrophoresis band of malate dehydrogenase,acid phosphatase and superoxide dismutase could be used as an indicator for the identification of gender and tissues of V. macrolepis,which would provide basic data for the developmental genetics,variety improvement and directed breeding of V. macrolepis groups,thus facilitating the development and protection of this valuable fish species.
文摘[Objective]The research aimed to provide scientific reference for reasonable utilization of polyacrylamide(PAM).[Method]After PAM treatment,the soil aggregates were classified through dry sieve analysis and the adsorption capacity and desorption capacity of all soil aggregates to phosphorus at different phosphorus concentrations were analyzed.[Result] The phosphorus adsorption and desorption of soil sample treated by PAM declined. The amount of phosphorus adsorption increased with the increase of phosphorus concentration and this increase was fast in low phosphorus concentration area but slow in high phosphorus concentration area.At different phosphorus concentrations,adsorption showed a へ shape changing trend.The phosphorus adsorption was related to phosphorus concentration and the 2-3 mm aggregate had the highest desorption rate while 0.1-0.25 mm aggregate and 0.45-1 mm aggregate had lowest desorption rate.[Conclusion]The PAM treatment generated significant influence on phosphorus adsorption and analytic features of aggregate in all size fractions.
基金Supported by the Scientific and Technological Program of Educational Department of Hebei Province(No.ZH2007116)~~
文摘[Objective] The aim was to optimize the SSR-PCR non-denatured polyacrylamide gel electrophoresis conditions in kernelled apricot.[Method]25 accessions of kernelled apricot and three accessions of edible apricot were selected as experimental materials to screen the repeatable SSR loci with high polymorphism by the use of SSR markers combined with non-denatured polyacrylamide gel electrophoresis.And the effect of different factors on electrophoresis conditions was compared to explore the optimal SSR-PCR non-denatured polyacrylamide gel electrophoresis conditions in kernelled apricot.[Result]The optimal non-denatured polyacrylamide gel electrophoresis conditions for SSR-PCR were established as follows：polyacrylamide gel concentration 6%,the ratio of acrylamide to bisacrylamide 29∶1,electrophoresis at 1 000 V for 2-3 h,and staining for 15 min within 0.1% AgNO3.[Conclusion]The optimum electrophoresis system has provided some technical foundations to further study the phylogenetic relationship of kernelled apricots by SSR markers.
基金Supported by Special Research Project of National Nonprofit Industry(3-20)Funded Projects of Modern Agricultural Technology System(nycytx-15)~~
文摘[Objective] The paper was to improve polyacrylamide gel electrophorus in Phytophthora infeatans SSR Marker.[Method] With the disease sample of P.infeatans collected from Guyuan in Ningxia Province in 2009 as test material,its DNA was extracted and amplified with PCR,and its products were carried out polyacrylamide gel electrophoresis.[Result] 12% polyacrylamide gel electrophoresis was used to detect primers D13,G11 and PI02,and 8% polyacrylamide gel electrophoresis was used to detect primers PI4B,PI63,SSR4,SSR8 and SSR11,then 0.1% silver nitrate was used to stain,and an ideal electrophoresis and staining effect was obtained.[Conclusion] The electrophoresis and staining method suitable for P.infeatans SSR Marker established in the study had the characteristics of high sensitivity,simple operation and clear bands,which was an effective,simple and quick detection method.
文摘Interaction of polymer-containing injected fluids with shale is a widely studied phenomenon, but much is still unknown about the interaction of charged polyacrylamides such as anionic and cationic polyacrylamides with shale. The nature of interaction of charged polyacrylamides with shale is not well understood, especially from the perspective of assessing the potential for polyacrylamides to cause formation damage. Zeta potential and rheological measurements were made for Chattanooga and Pride Mountain shales suspended in polyacrylamide solutions with and without inorganic salts and tetramethyl ammonium chloride（TMAC）. The change in zeta potential and viscosity with time was recorded. The magnitude of decrease in the absolute value of zeta potential with time is indicative of adsorption of polymer on the surface of shale and serves as a measure of the extent of polymer interaction with shale. The salts that were used in this study are potassium chloride（KCl）, sodium chloride（Na Cl）. This study quantified the interaction of anionic and cationic polyacrylamide with different North American shales.From the experimental results, it was determined that the polyacrylamides can interact strongly with shale, particularly the cationic polyacrylamide. The objective of this study was to determine the extent of interaction of anionic and cationic polyacrylamide with each shale sample in the presence of additives such as salts.
文摘Although inorganic phosphate is an essential plant nutrient, elevated levels in surface waters lead to adverse effects in the environment. These effects are attributed to runoff from rain or irrigation events that may cause the sorbed phosphate to be transported from the application sites and to move into neighboring watersheds. Increased phosphate concentration in watersheds may lead to a variety of environmental problems including increased algal blooms, bacterial contamination, and in some cases eutrophication. To overcome these effects, polymer flocculants have been shown to reduce the phosphate concentration in water by removing suspended solids and thereby removing the phosphate sorbed to the solids. The purpose of this study is to determine the amount, if any, of phosphate removed by several commercial polymers. The polymers chosen include the polyacrylamides Magnifloc 494C, Magnifloc 985N and Poly (diallyldimethyl ammonium chloride) (Poly (DADMAC)). Using these polymers, it is discovered that the positive charge density of the polymers affects the amount of phosphate removed from solution with Poly (DADMAC) (having 100% positive charge density) removing 40% of the phosphate from a solution containing 10 ppm phosphate.
基金supported by the National Natural Science Foundation of China(No.51273189)the National Science and Technology Major Project of the Ministry of Science and Technology of China(No.2016ZX05016)the National Science and Technology Major Project of the Ministry of Science and Technology of China(No.2016ZX05046)
文摘Partially hydrolyzed polyacrylamide （HPAM） has been widely used for water shut-off and profile control to enhance oil recovery. Herein, we reported a novel technique by which the crosslinking between HPAM and Cr3＋ in aqueous solutions at 60 ℃ can be delayed effectively. Citric acid was selected as an organic complexing agent of Cr3＋ so that the crosslinking between HPAM and Cr3＋ can be prevented completely. Due to the decomposi- tion of the bicarbonate （HCO3-） embedded in solution, CO2 released from solution and the pH value of solution increased gradually. The degree of ionization of HPAM and its ability to complex with Cr3＋ increased accordingly. When the complexation of Cr3＋ with HPAM is stronger than that with citric acid, the viscosity of the HPAM solution increased signif- icantly. Under the closed condition, together with the existence of potassium dihydrogen phosphate （KH2PO4）, the release of CO2 was very slow and the condition was highly con- trolled so that the ionization of HPAM was prevented initially. Furthermore, the hydrogen bonding interactions between HPAM and melamine embedded in solution previously also postponed the ionization of HPAM. As a result, the crosslinking between HPAM and Cr3＋ can be delayed for almost one month, completely meeting the requirements for deep water shut-off and profile control to enhance oil recovery.
基金Supported by National Natural Science Foundation(30671061)Shanxi Province Natural Science Foundation(2008011059-1)~~
文摘All of the Rho GTPase seems to form a special sub-family,because such a sub-family has so far only found in plants,and then named Rop GTPase,which directly involved in and regulated of muscle actin cytoskeletal reorganization,such as a series of signal transductions.The efficient purification technology and the means of ROP GTPase in wheat are the key basis of the studies on its functions and prosperities.And it has a very important theoretical and practical significance in the signal transduction and F-act...
基金supported by the Scientific Technology Research and Development Program of Shandong,China(No. 2009GG10006003)
文摘Produced water from polymer flooding is difficult to treat due to its high polymer concentration,high viscosity,and emulsified characteristics.The dithiocarbamate flocculant,DTC(T403),was prepared by the amine-terminated polyoxypropane-effier compound known as Jeffamine-T403.The product was characterized by IR spectra and elemental analysis.The DTC agent chelating with Fe2+produced a network polymer matrix,which captured and removed oil droplets efficiently.Oil removal by the flocculent on simulated produced water with 0,200,500,900 mg/L of partially hydrolyzed polyacrylamide(HPAM)was investigated for aspects of effectiveness of DTC(T403)dosage and concentrations of HPAM and Fe2+ions in the wastewater.Results showed that HPAM had a negative influence on oil removal efficiency when DTC(T403)dosage was lower than 20 mg/L.However,residual oil concentrations in tested samples with different concentrations of HPAM all decreased below 10 mg/L when DTC(T403)dosage reached 30 mg/L.The concentration of Fe2+in the initial wastewater had a slight effect on oil removal at the range of 2-12 mg/L.Results showed that Fe3+could not be used in place of Fe2+as Fe3+could not react with DTC under flocculated conditions.The effects of mineral salts ions were also investigated.
