Propolis is a natural resin used around the world to treatment of several diseases. We evaluated the effect of Brazilian propolis (P1) in guinea pig isolated trachea in vitro contracted with hista-mine, in paw oedema ...Propolis is a natural resin used around the world to treatment of several diseases. We evaluated the effect of Brazilian propolis (P1) in guinea pig isolated trachea in vitro contracted with hista-mine, in paw oedema induced by histamine in mice and anti-ulcerogenic effect of propolis formulation in mice. We used a P1 extract from South of Brazil to produce a formulation containing sodium bicarbonate and propolis dry extract (2%). In the guinea pig trachea Brazilian propolis extract (10 μg/mL) produced a non-significant inhibition in the cumulative response curve for histamine. However, the dose of 100 μg/mL shown had a significant inhibitory effect on the contraction induced by histamine (51% ± 5%). In the mouse paw oedema induced by intraplantar injection of histamine (50 μg/paw), the results showed that the treatment of the mice with P1 (10 or 100 mg/Kg (p.o) or 1 or 10 mg/Kg (i.p)), 0.5 h beforehand, significantly inhibited the paw oedema with maximal inhibition (MI) of 25% or 42% by p.o. route or 22% or 37% by i.p. route, respectively. Finally we have pre-treated mice with P1 formulation (20 mg/Kg or 40 mg/Kg, p.o, one time) or vehicle (powder) in animals submitted to diclofenac-induced ulcer, after 8 h P1 formulation inhibited of 43% or 83% of ulcers scores, respectively. Results showed that P1 formulation inhibited the ulcerogenic effect induced by diclofenac. Results suggested also, at least in part, the antiulcerogenic effect of formulation containing standardized extract of propolis can be due to the antagonistic action on the histaminergic system.展开更多
From a point of magmatic view,the rupturing Gondwana Supercontinent is registered on the South American shelf in continental flood basalts,mafic dyke swarms,basins rift and,to a lesser extent,by intrusions alkaline.Am...From a point of magmatic view,the rupturing Gondwana Supercontinent is registered on the South American shelf in continental flood basalts,mafic dyke swarms,basins rift and,to a lesser extent,by intrusions alkaline.Among those展开更多
There is a consensus among scholars of ancient Greek history that the phylê1was not only a functional unit belonging to political systems of Greek communities,but that it also played a decisive part in the singul...There is a consensus among scholars of ancient Greek history that the phylê1was not only a functional unit belonging to political systems of Greek communities,but that it also played a decisive part in the singular process known as the rise of the polis,i.e.the transformation from settlements into political communities of citizens.2Nevertheless,little attention has been paid to the concrete political function fulfilled by the phylai in particular poleis.Only the famous展开更多
Purpose: This study assessed the roughness of two injection-molded, thermoplastic materials used for denture bases compared with a polyamide material and compression molded Polymethylmethacrylate (PMMA) after the adju...Purpose: This study assessed the roughness of two injection-molded, thermoplastic materials used for denture bases compared with a polyamide material and compression molded Polymethylmethacrylate (PMMA) after the adjustment and re-polishing with either a laboratory protocol or a chair side protocol. Methods: Forty specimens, each of PMMA, Valplast, DuraFlex, Dura Cetal were fabricated and finished according to individual manufactures’ instructions. These materials were adjusted with tungsten carbide (TC) burs to mimic gross adjustments, and then re-polished either on a lathe or bonded silicon carbide (B-SC). Following instrumentation, the specimens were assessed using contact profilometry and scanning electron microscopy. Two-factor ANOVA was used to determine significant differences in mean surface roughness (Ra and Rmax), with included factors being material type and re-polishing regimen. Results: Mean Ra values ranged from 0.26 (DuraFlex control) to 1.82 (Valplast adjusted with TC burs). Mean Rmax values ranged from 1.88 (Dura Flex control) to 13.76 (Valplast adjusted with TC burs). Two-factor ANOVA revealed that interaction of both factors was significant (p Ra and Rmax. There was a statistically significant increase in both Ra (p Rmax (p < 0.05) for all material types following the gross adjustment. With the exception of DuraFlex, re-polishing of samples that were previously adjusted with TC burs, on the dental lathe produced surfaces that were comparable to control samples. Conclusion: Adjustment of DuraFlex should be kept to a minimum since the adjustment produced the significant surface detriment that could not be corrected with either of the polishing regimens.展开更多
Polis 是古希腊社会的一种政治组织,英译为city-state, 汉译为“城邦”。这些译名都算不上完全准确,因为在英语和汉语中都没有确切的对译词,城邦并不是城市也不能说就是一个国家,但是比起城市,一个城邦更像是一个国家。要得到polis确切...Polis 是古希腊社会的一种政治组织,英译为city-state, 汉译为“城邦”。这些译名都算不上完全准确,因为在英语和汉语中都没有确切的对译词,城邦并不是城市也不能说就是一个国家,但是比起城市,一个城邦更像是一个国家。要得到polis确切的翻译,对何为城邦,它对希腊人有何意义这样的问题如果缺乏明确的了解,就不能正确理解希腊历史,是不可能找到准确的译名的。展开更多
Herein,manganese(Mn)‑doped poly(1,5‑diaminonaphthalene)(PN)electrode material(Mn@PN)was synthesized via chemical oxidative polymerization.The material′s distinctive vesicular architecture enables rapid ion transport ...Herein,manganese(Mn)‑doped poly(1,5‑diaminonaphthalene)(PN)electrode material(Mn@PN)was synthesized via chemical oxidative polymerization.The material′s distinctive vesicular architecture enables rapid ion transport while maintaining the structural stability of the electrode under continuous charge‑discharge cycles.Electrochemical characterization under a three‑electrode system revealed exceptional rate capability:Mn@PN delivered an ultrahigh specific capacitance of 10318 F·g^(-1) at a low current density of 3 A·g^(-1) and retained 9415 F·g^(-1)(91.2%retention compared to the value at 3 A·g^(-1))even at an ultrahigh current density of 50 A·g^(-1).Moreover,the material exhibited 97.4%capacitance retention after 9000 cycles at 30 A·g^(-1),corresponding with a low capacitance decay rate of 0.003‰per cycle,significantly outperforming conventional conductive polymers like polyaniline(PANI).An asymmetric supercapacitor assembled with Mn@PN as the positive electrode(Mn@PN||AC)achieved an energy density of 328 Wh·kg^(-1) at 15 A·g^(-1) and retained 80.7%of its initial specific capacitance after 4000 cycles at 20 A·g^(-1).展开更多
In this study,a series of poly(ethylene succinate)-b-poly(butylene carbonate)(PES-b-PBC)multiblock copolymers were prepared through the chain-extension reaction of hydroxyl-terminated PES(PES-OH)and hydroxyl-terminate...In this study,a series of poly(ethylene succinate)-b-poly(butylene carbonate)(PES-b-PBC)multiblock copolymers were prepared through the chain-extension reaction of hydroxyl-terminated PES(PES-OH)and hydroxyl-terminated PBC(PBC-OH)prepolymers with 1,6-hexmethylene diisocyanate(HDI)as a chain extender.The effects of the prepolymer molecular weight and content on the structure and application properties of the PES-b-PBC copolymers were systematically investigated using various techniques.It was found that the compatibility of PES and PBC blocks in PES-b-PBC copolymers can be greatly enhanced by lowering the length of the prepolymers,and the amorphous phase of the PES and PBC chain segments in the PES-b-PBC copolymer would transform from immiscibility and partial miscibility to miscibility when the number-average molecular weight(M_(n))of the PES-OH and PBC-OH prepolymers is less than 2000 g/mol.Only the crystal structure of bare PES can be observed in the wide-angle X-ray diffraction(WAXD)spectrum of the PES-b-PBC copolymers,but their crystallinity degrees were found to decrease with increasing PBC fraction.The thermal behavior,crystallization performance,rheological properties,mechanical properties,and degradation properties of the PES-b-PBC multiblock copolymers can be easily modulated by altering the block length and composition of the prepolymers,offering potential applications in biodegradable materials.展开更多
Poly(ethylene succinate)(PES),a promising biodegradable polyester with cost advantages,suffers from inherently slow crystallization kinetics,which severely limits its processability and practical applications.To addre...Poly(ethylene succinate)(PES),a promising biodegradable polyester with cost advantages,suffers from inherently slow crystallization kinetics,which severely limits its processability and practical applications.To address this challenge,this study explored the use of commercially available,low-cost,and food-safe sugar alcohols,including Xylitol(Xy),D-sorbitol(DS),and D-mannitol(DM),as effective nucleating agents for PES.Remarkably,all three polyols significantly enhanced the nucleation and crystallization ability of PES,with DM exhibiting the most pronounced effect.DM increased the crystallization temperature by up to 23.9°C and accelerated the overall crystallization rate by more than 13-fold at only 0.5 wt%loading level.Through a combination of differential scanning calorimetry(DSC),polarized optical microscopy(POM),and wide-angle X-ray diffraction(WAXD)analyses,we revealed that DM promotes PES crystallization via a dual mechanism:epitaxial templating facilitated by excellent lattice matching,and enhanced chain adjustment through intermolecular hydrogen-bonding interactions.In contrast,Xy and DS primarily function through hydrogen-bonding interactions.This work not only identifies DM as a highly efficient,economical,and industrially viable nucleating agent for PES,but also provides fundamental insights into the role of the molecular structure and crystallization ability of nucleating agents in regulating polymer crystallization.展开更多
Smart pesticide delivery systems based on stimuli-responsive nanocarriers have attracted considerable attention because of their potential to enhance pesticide efficiency while reducing environmental risks.In this stu...Smart pesticide delivery systems based on stimuli-responsive nanocarriers have attracted considerable attention because of their potential to enhance pesticide efficiency while reducing environmental risks.In this study,a novel p H/glutathione dual-responsive pesticide delivery system was constructed through the synthesis of disulfide-bridged hollow mesoporous organosilica nanospheres(HMONs)via the St??ber method,followed by poly(acrylic acid)(PAA)coating through distillation-precipitation polymerization to form HMONs@PAA nanocomposites.The resulting abamectin-loaded system(Abamectin-HMONs@PAA)demonstrated a 12.73% pesticide loading capacity and significantly improved photostability,retaining twice as much active ingredient as free abamectin after 250 h of UV irradiation(36 W).Release studies revealed p H-and glutathione-dependent characteristics,with cumulative releases in acidic conditions exceeding those in neutral and alkaline environments by 18.66% and 40.98%,respectively,and a 14.2% increase in glutathione-containing solution(0.2 mmol·L^(-1) in 70% ethanol)after 97 h.Bioassays showed superior performance against Plutella xylostella,with a 13.33% reduction in survival rate compared to conventional suspension at equivalent dosage(40 mg·L^(-1)),while maintaining efficacy after extensive rainfall simulation(20 events over 10 days).This study provides a promising approach for developing environmentally responsive nanopesticides with enhanced durability and controlled-release properties,offering significant potential for sustainable crop protection.展开更多
In-situ poly(1,3-dioxolane)(PDOL)-based electrolyte has received extensive attention in the research of lithium metal batteries due to its high stability to lithium anode and simple processing.However,it is still face...In-situ poly(1,3-dioxolane)(PDOL)-based electrolyte has received extensive attention in the research of lithium metal batteries due to its high stability to lithium anode and simple processing.However,it is still faced with defects such as low intrinsic ionic conductivity,a narrow electrochemical window,and poor thermal stability.A crosslinking and fluorination molecular design strategy toward PDOL is proposed to tackle the issues above.The amorphous crosslinked structure effectively improves ionic conductivity by inhibiting long-chain crystallization.Especially,the antioxidant–CF_(3)groups,stable crosslinked structure,and reduced terminal hydroxyl groups significantly enhance the electrochemical oxidation stability with a superb high-voltage window of 4.7 V.In addition,the designed electrolyte also exhibits obviously improved thermal stability with no deformation at 120°C for 5 min.Furthermore,the semi-solid NCM811||Li batteries exhibit a favourable capacity retention of 88.8%after 150 cycles at 0.5 C.Even assembled with NCM622 cathode working at 4.5 V,the semi-solid batteries can still show a satisfactory capacity retention of 85.3%after 100 cycles at 0.5 C.Also,a 0.1 Ah NCM811||Li pouch cell with active materials loading of 9 mg/cm2 demonstrates satisfactory cycling stability and working ability,which shows promising practical application prospects.展开更多
Eukaryotic mRNAs are polyadenylated at their 3’-ends,and the poly(A)tails play critical roles in post-transcriptional gene regulation by influencing mRNA stability and translation.Here,we describe the biological proc...Eukaryotic mRNAs are polyadenylated at their 3’-ends,and the poly(A)tails play critical roles in post-transcriptional gene regulation by influencing mRNA stability and translation.Here,we describe the biological processes and major protein factors that control poly(A)tail synthesis and shortening.We also discuss recent breakthroughs in poly(A)tail sequencing methods that enable high throughput and accurate measurement of poly(A)tail lengths.Finally,we review how poly(A)-tail regulators and poly(A)-tail-mediated post-transcriptional mechanisms affect stem cell fate and early embryonic development.展开更多
Although amide-and hydrazide-based nucleating agents have been extensively used to enhance the crystallization performance of poly(lactic acid)(PLA),structurally similar nucleating agents exhibit significant differenc...Although amide-and hydrazide-based nucleating agents have been extensively used to enhance the crystallization performance of poly(lactic acid)(PLA),structurally similar nucleating agents exhibit significant differences in their crystallization-promoting efficiency,and the underlying mechanism remains unclear.In this study,a series of nucleating agents,including N,N-diphenylterephthalamide(DPTA),N,N,N-triphenyl-1,3,5-benzenetricarboxamide(TPTA),N,N-diphenyl terephthalohydrazide(DBTA),and N,N,N-tribenzoyl-1,3,5-benzenetricarbohydrazide(TBTA),were designed and synthesized to investigate the differences in their effects on the crystallization performance of PLA.Density functional theory(DFT)and molecular dynamics(MD)simulations showed that DBTA had a smaller electrostatic potential difference(66.2 kcal/mol).During the cooling process,DBTA could stably form more intermolecular hydrogen bonds with PLA and exhibit a higher interaction energy,thus theoretically enabling more efficient promotion of PLA crystallization.Further differential scanning calorimetry(DSC)results revealed that at a 0.5wt%loading of DBTA,the crystallization peak temperature of the PLA-DBTA composite reached 118.1℃during cooling,whereas no distinct crystallization peak was observed for pure PLA under identical conditions.The crystallinity of the composite was significantly increased to 58.4%compared to 14.6%of pure PLA.Moreover,under isothermal crystallization at 130℃,DBTA reduced the half-crystallization time of PLA to 2.9min,while the half-crystallization time for pure PLA was 27.4 min.Time-resolved Fourier transform infrared spectroscopy(FTIR)results also confirmed that DBTA promoted the formation of gt conformational isomers of PLA during the crystallization process.This study elucidates the mechanism behind the performance differences between structurally similar nucleating agents in regulating PLA crystallization from the perspective of molecular electrostatic potential and hydrogen bonding interactions,providing a theoretical basis for the molecular design of efficient nucleating agents.展开更多
The introduction of high-k/metal gate(HK/MG)technology enables independent tuning of N-type metal-oxide-semi-conductor(NMOS)and P-type metal-oxide-semiconductor(PMOS)threshold voltages,facilitating advanced nodes and ...The introduction of high-k/metal gate(HK/MG)technology enables independent tuning of N-type metal-oxide-semi-conductor(NMOS)and P-type metal-oxide-semiconductor(PMOS)threshold voltages,facilitating advanced nodes and improv-ing overall chip performance.However,severe pattern loading effects during PMOS device fabrication pose challenges in dummy poly removal.This work reports the optimization of the photoresist etch back(PREB)process,providing a wider pro-cess window for subsequent AL CMP.By tuning the PR coating uniformity to 1.6%and applying four-zone electrostatic chuck(ESC)temperature control,the wafer-level uniformities of PR,SiN,and SiO_(2)were reduced to 6.3%,2.3%,and 5.1%,respectively.An optimized over etch(OE)recipe with a high selectivity of PR:SiN:SiO_(2)≈1:1:6 effectively balanced gate height loading between N-and PMOS regions.Furthermore,precise EB1 time tuning enabled defect removal,while advanced KLA inspection ensured early detection of critical failure modes.Collectively,these measures establish a robust and stable PREB process for advanced logic device fabrication.展开更多
Corn starch(CS)is a renewable,biodegradable polysaccharide valued for its film-forming ability,yet native CS films exhibit lowmechanical strength,highwater sensitivity,and limited thermal stability.This study improves...Corn starch(CS)is a renewable,biodegradable polysaccharide valued for its film-forming ability,yet native CS films exhibit lowmechanical strength,highwater sensitivity,and limited thermal stability.This study improves CS-based films by blending with poly(vinyl alcohol)(PVA)or glycerol(GLY)and using citric acid(CA)as a green,non-toxic cross-linker.Composite films were prepared by casting CS–PVA or CS-GLY with CA at 0%-0.20%(w/w of starch).The influence of CA on physicochemical,mechanical,optical,thermal,and water barrier properties was evaluated.CA crosslinking markedly enhanced the tensile strength,water resistance,and thermal stability of CS-PVA films while increasing transparency in CS–GLY films.At 0.20%CA,the composite achieved 34.99MPa tensile strength,reducedwater vapor permeability,andminimized water uptake.FTIR confirmed ester bond formation between CAand hydroxyl groups of CS,PVA,and GLY,whereas thermal analysis showed higher decomposition temperatures and lower weight loss in crosslinked films.Increasing CA levels also decreased opacity and improved light transmittance,indicating greater homogeneity and reduced crystallinity.This dual-polymer matrix combined with a natural crosslinking strategy provides a sustainable route to high-performance,biodegradable CS-based packaging materials.展开更多
Silica aerogels(SAs)impart low density and excellent thermal insulation to polymer systems,yet incorporating hydrophobic SAs into aqueous rubber latex systems remains challenging owing to their poor dispersibility and...Silica aerogels(SAs)impart low density and excellent thermal insulation to polymer systems,yet incorporating hydrophobic SAs into aqueous rubber latex systems remains challenging owing to their poor dispersibility and potential to destabilize the latex.Although previous studies have dispersed SAs in aqueous poly(vinyl alcohol)(PVA),the stability of such dispersions and their effectiveness as bridging media for latex integration have not been thoroughly evaluated,which limits their practical application in latex compounding.This study systematically examined how the surface chemistry governs hydrolytic stability,interfacial behavior,and latex compatibility in PVA-assisted aqueous processing.Two hydrophobic SAs were prepared:ethoxy-modified SA(E-SA)and methyl-modified SA(M-SA).Both initially formed a homogeneous PVA slurry,but E-SA rapidly hydrolyzed its surface—OCH_(2)CH_(3)groups,releasing ethanol,becoming hydrophilic,and undergoing irreversible nanopore collapse.In contrast,M-SA maintains its structural integrity and hydrophobicity because its—Si(CH_(3))_(3)groups are highly resistant to hydrolysis.This divergence dictates the behavior during latex blending.The ethanol released from E-SA disrupts electrostatic and steric stabilization,inducing latex coagulation,whereas M-SA/PVA dispersions preserve colloidal stability across diverse latex systems.As a practical demonstration,M-SA-reinforced chlorosulfonated polyethylene(CSM)rubber latex composites show more than a 50%reduction in thermal conductivity while maintaining chemical resistance,enabling high-performance insulating protective gloves and coatings.This work establishes a critical link between aerogel surface chemistry and aqueous processing stability,providing a mechanistic foundation for the rational design of water-based rubber/silica aerogel composites and next-generation thermal insulation materials.展开更多
Poly(phenylene oxide)(PPO)exhibits excellent dielectric properties,making it an ideal substrate for high-frequency,high-speed copper-clad laminates.The phenolic hydroxyl group at the end of PPO plays a key role in its...Poly(phenylene oxide)(PPO)exhibits excellent dielectric properties,making it an ideal substrate for high-frequency,high-speed copper-clad laminates.The phenolic hydroxyl group at the end of PPO plays a key role in its reactivity.Accurately quantifying the phenolic hydroxyl content in PPO is essential but challenging.In this study,we proposed a method for measuring the phenolic hydroxyl content of PPO using differential UV absorption spectroscopy.In alkaline solutions,the phenolic hydroxyl in PPO completely ionizes to form phenoxide ions,leading to a significant increase in UV absorbance at approximately 250 and 300 nm.Notably,the differential UV absorbance at approximately 300 nm was directly proportional to the phenolic hydroxyl concentration.Using 2,6-dimethylphenol as a standard,a calibration curve was established to relate the phenolic hydroxyl concentration to differential UV absorbance at approximately 300 nm,providing a precise and straightforward method for phenolic hydroxyl quantification in PPO with distinct advantages over conventional techniques.展开更多
This study aimed to systematically regulate the performance of 4D printing composites by investigating the synergistic effects of dicumyl peroxide(DCP)and maleic anhydride-grafted polyethylene(MAH-g-PE)on a poly(lacti...This study aimed to systematically regulate the performance of 4D printing composites by investigating the synergistic effects of dicumyl peroxide(DCP)and maleic anhydride-grafted polyethylene(MAH-g-PE)on a poly(lactic acid)/thermoplastic polyurethane(PLA/TPU)matrix.Specifically,using a 70 wt%/30 wt%PLA/TPU matrix and an L_(9)(3^(2))orthogonal design,composites were evaluated via morphology,shape memory,mechanical tests,and multi-criteria analysis.Moderate DCP enhanced crosslinking,improving storage modulus and thermal stability,while excessive DCP caused brittleness.Furthermore,MAH-g-PE effectively improved interfacial compatibility,and its synergy with DCP was dosage-dependent.Consequently,Sample 5 achieved optimal performance,exhibiting uniform fracture morphology,a shape fixation rate of98.8%with the fastest recovery,and balanced strength-ductility.Multi-criteria analysis identified elongation at break and recovery time as the top contributing factors,with consistent rankings validated by Spearman analysis(ρ=0.833,p<0.01).In summary,adjusting DCP and MAH-g-PE contents effectively modulates the crosslinking structure and interfacial properties of PLA/TPU composites,providing a viable strategy for developing high-performance,tunable 4D printing materials.展开更多
Thermoplastic polyurethane(TPU)consists of a hardsegment and a soft segment,where the former affords mechanical strength and thermalstability,while the latter provides a possibility of good ionic conductivity by promo...Thermoplastic polyurethane(TPU)consists of a hardsegment and a soft segment,where the former affords mechanical strength and thermalstability,while the latter provides a possibility of good ionic conductivity by promoting dissociation of ions from the lithium salt.Thus,TPU attracts a wide interest recently as a promising polymer electrolyte for solid-state lithium batteries.However,the relatively low ionic conductivity of TPU still restricts its actual applications due to the aggregation of polymer chains,which greatly reduces the dissociation of lithium salts.Herein,a strategy to address this challenge was adopted by in situ polymerization poly(ethylene glycol diacrylate)(PEGDA)in fully dispersed TPU.Hence a stretchable solid-state electrolyte(denoted as TELL and the contrast sample was denoted as TLL)with high ionic conductivity of 7.18×10^(-4) S/cm was obtained at room temperature.The Li^(+)transference number is 0.85 in Li|TELL|Li cell and can stably undergo charge-discharge cycles for 1400 h at a current density of 0.1 mA/cm^(2),while the contrast sample is short-circuited after 634 h of cycling.The LiFePO_(4)|TELL|Li cell achieves a capacity retention of 78.93%after 200 cycles at 2 C.The LiFePO_(4)|TLL| Li cellonly gains the capacity retention of 51.9%after 50 cyclesat the same current density.So,the method adopted here may provide a new approach to realize a flexible solid-state electrolyte with high ion-conductivity.展开更多
文摘Propolis is a natural resin used around the world to treatment of several diseases. We evaluated the effect of Brazilian propolis (P1) in guinea pig isolated trachea in vitro contracted with hista-mine, in paw oedema induced by histamine in mice and anti-ulcerogenic effect of propolis formulation in mice. We used a P1 extract from South of Brazil to produce a formulation containing sodium bicarbonate and propolis dry extract (2%). In the guinea pig trachea Brazilian propolis extract (10 μg/mL) produced a non-significant inhibition in the cumulative response curve for histamine. However, the dose of 100 μg/mL shown had a significant inhibitory effect on the contraction induced by histamine (51% ± 5%). In the mouse paw oedema induced by intraplantar injection of histamine (50 μg/paw), the results showed that the treatment of the mice with P1 (10 or 100 mg/Kg (p.o) or 1 or 10 mg/Kg (i.p)), 0.5 h beforehand, significantly inhibited the paw oedema with maximal inhibition (MI) of 25% or 42% by p.o. route or 22% or 37% by i.p. route, respectively. Finally we have pre-treated mice with P1 formulation (20 mg/Kg or 40 mg/Kg, p.o, one time) or vehicle (powder) in animals submitted to diclofenac-induced ulcer, after 8 h P1 formulation inhibited of 43% or 83% of ulcers scores, respectively. Results showed that P1 formulation inhibited the ulcerogenic effect induced by diclofenac. Results suggested also, at least in part, the antiulcerogenic effect of formulation containing standardized extract of propolis can be due to the antagonistic action on the histaminergic system.
文摘From a point of magmatic view,the rupturing Gondwana Supercontinent is registered on the South American shelf in continental flood basalts,mafic dyke swarms,basins rift and,to a lesser extent,by intrusions alkaline.Among those
文摘There is a consensus among scholars of ancient Greek history that the phylê1was not only a functional unit belonging to political systems of Greek communities,but that it also played a decisive part in the singular process known as the rise of the polis,i.e.the transformation from settlements into political communities of citizens.2Nevertheless,little attention has been paid to the concrete political function fulfilled by the phylai in particular poleis.Only the famous
文摘Purpose: This study assessed the roughness of two injection-molded, thermoplastic materials used for denture bases compared with a polyamide material and compression molded Polymethylmethacrylate (PMMA) after the adjustment and re-polishing with either a laboratory protocol or a chair side protocol. Methods: Forty specimens, each of PMMA, Valplast, DuraFlex, Dura Cetal were fabricated and finished according to individual manufactures’ instructions. These materials were adjusted with tungsten carbide (TC) burs to mimic gross adjustments, and then re-polished either on a lathe or bonded silicon carbide (B-SC). Following instrumentation, the specimens were assessed using contact profilometry and scanning electron microscopy. Two-factor ANOVA was used to determine significant differences in mean surface roughness (Ra and Rmax), with included factors being material type and re-polishing regimen. Results: Mean Ra values ranged from 0.26 (DuraFlex control) to 1.82 (Valplast adjusted with TC burs). Mean Rmax values ranged from 1.88 (Dura Flex control) to 13.76 (Valplast adjusted with TC burs). Two-factor ANOVA revealed that interaction of both factors was significant (p Ra and Rmax. There was a statistically significant increase in both Ra (p Rmax (p < 0.05) for all material types following the gross adjustment. With the exception of DuraFlex, re-polishing of samples that were previously adjusted with TC burs, on the dental lathe produced surfaces that were comparable to control samples. Conclusion: Adjustment of DuraFlex should be kept to a minimum since the adjustment produced the significant surface detriment that could not be corrected with either of the polishing regimens.
文摘Herein,manganese(Mn)‑doped poly(1,5‑diaminonaphthalene)(PN)electrode material(Mn@PN)was synthesized via chemical oxidative polymerization.The material′s distinctive vesicular architecture enables rapid ion transport while maintaining the structural stability of the electrode under continuous charge‑discharge cycles.Electrochemical characterization under a three‑electrode system revealed exceptional rate capability:Mn@PN delivered an ultrahigh specific capacitance of 10318 F·g^(-1) at a low current density of 3 A·g^(-1) and retained 9415 F·g^(-1)(91.2%retention compared to the value at 3 A·g^(-1))even at an ultrahigh current density of 50 A·g^(-1).Moreover,the material exhibited 97.4%capacitance retention after 9000 cycles at 30 A·g^(-1),corresponding with a low capacitance decay rate of 0.003‰per cycle,significantly outperforming conventional conductive polymers like polyaniline(PANI).An asymmetric supercapacitor assembled with Mn@PN as the positive electrode(Mn@PN||AC)achieved an energy density of 328 Wh·kg^(-1) at 15 A·g^(-1) and retained 80.7%of its initial specific capacitance after 4000 cycles at 20 A·g^(-1).
基金financially supported by the Science and Technology Projects of Changji Prefecture(No.2023112258)Shihezi Coal Chemical Industry Common Technology Research Institute Project(No.MGJY0104)the Program for Young Innovative Talents of Shihezi University(No.CXFZ202302).
文摘In this study,a series of poly(ethylene succinate)-b-poly(butylene carbonate)(PES-b-PBC)multiblock copolymers were prepared through the chain-extension reaction of hydroxyl-terminated PES(PES-OH)and hydroxyl-terminated PBC(PBC-OH)prepolymers with 1,6-hexmethylene diisocyanate(HDI)as a chain extender.The effects of the prepolymer molecular weight and content on the structure and application properties of the PES-b-PBC copolymers were systematically investigated using various techniques.It was found that the compatibility of PES and PBC blocks in PES-b-PBC copolymers can be greatly enhanced by lowering the length of the prepolymers,and the amorphous phase of the PES and PBC chain segments in the PES-b-PBC copolymer would transform from immiscibility and partial miscibility to miscibility when the number-average molecular weight(M_(n))of the PES-OH and PBC-OH prepolymers is less than 2000 g/mol.Only the crystal structure of bare PES can be observed in the wide-angle X-ray diffraction(WAXD)spectrum of the PES-b-PBC copolymers,but their crystallinity degrees were found to decrease with increasing PBC fraction.The thermal behavior,crystallization performance,rheological properties,mechanical properties,and degradation properties of the PES-b-PBC multiblock copolymers can be easily modulated by altering the block length and composition of the prepolymers,offering potential applications in biodegradable materials.
基金financially supported by the National Natural Science Foundation of China(Nos.22173116 and 22473113)the Science Foundation of China University of Petroleum,Beijing(No.2462025YJRC032)for providing financial support.
文摘Poly(ethylene succinate)(PES),a promising biodegradable polyester with cost advantages,suffers from inherently slow crystallization kinetics,which severely limits its processability and practical applications.To address this challenge,this study explored the use of commercially available,low-cost,and food-safe sugar alcohols,including Xylitol(Xy),D-sorbitol(DS),and D-mannitol(DM),as effective nucleating agents for PES.Remarkably,all three polyols significantly enhanced the nucleation and crystallization ability of PES,with DM exhibiting the most pronounced effect.DM increased the crystallization temperature by up to 23.9°C and accelerated the overall crystallization rate by more than 13-fold at only 0.5 wt%loading level.Through a combination of differential scanning calorimetry(DSC),polarized optical microscopy(POM),and wide-angle X-ray diffraction(WAXD)analyses,we revealed that DM promotes PES crystallization via a dual mechanism:epitaxial templating facilitated by excellent lattice matching,and enhanced chain adjustment through intermolecular hydrogen-bonding interactions.In contrast,Xy and DS primarily function through hydrogen-bonding interactions.This work not only identifies DM as a highly efficient,economical,and industrially viable nucleating agent for PES,but also provides fundamental insights into the role of the molecular structure and crystallization ability of nucleating agents in regulating polymer crystallization.
基金financially supported by the Jiangsu Forestry Science and Technology Innovation and Promotion Project(No.LYKJ-Nanjing[2022]02)the Jiangsu Agricultural Science and Technology Innovation Fund(No.CX(23)3090)。
文摘Smart pesticide delivery systems based on stimuli-responsive nanocarriers have attracted considerable attention because of their potential to enhance pesticide efficiency while reducing environmental risks.In this study,a novel p H/glutathione dual-responsive pesticide delivery system was constructed through the synthesis of disulfide-bridged hollow mesoporous organosilica nanospheres(HMONs)via the St??ber method,followed by poly(acrylic acid)(PAA)coating through distillation-precipitation polymerization to form HMONs@PAA nanocomposites.The resulting abamectin-loaded system(Abamectin-HMONs@PAA)demonstrated a 12.73% pesticide loading capacity and significantly improved photostability,retaining twice as much active ingredient as free abamectin after 250 h of UV irradiation(36 W).Release studies revealed p H-and glutathione-dependent characteristics,with cumulative releases in acidic conditions exceeding those in neutral and alkaline environments by 18.66% and 40.98%,respectively,and a 14.2% increase in glutathione-containing solution(0.2 mmol·L^(-1) in 70% ethanol)after 97 h.Bioassays showed superior performance against Plutella xylostella,with a 13.33% reduction in survival rate compared to conventional suspension at equivalent dosage(40 mg·L^(-1)),while maintaining efficacy after extensive rainfall simulation(20 events over 10 days).This study provides a promising approach for developing environmentally responsive nanopesticides with enhanced durability and controlled-release properties,offering significant potential for sustainable crop protection.
基金the financial support from the National Natural Science Foundation of China (No. 52072390)the National High-Level Talents Special Support Program (Leading Talent of Technological Innovation)+2 种基金the China Postdoctoral Science Foundation (No. 2023M743648)the Young Scientists Fund of the National Natural Science Foundation of China (No. 52302330)the support from the Shanghai Emperor of Cleaning Hi-Tech Co.,LTD
文摘In-situ poly(1,3-dioxolane)(PDOL)-based electrolyte has received extensive attention in the research of lithium metal batteries due to its high stability to lithium anode and simple processing.However,it is still faced with defects such as low intrinsic ionic conductivity,a narrow electrochemical window,and poor thermal stability.A crosslinking and fluorination molecular design strategy toward PDOL is proposed to tackle the issues above.The amorphous crosslinked structure effectively improves ionic conductivity by inhibiting long-chain crystallization.Especially,the antioxidant–CF_(3)groups,stable crosslinked structure,and reduced terminal hydroxyl groups significantly enhance the electrochemical oxidation stability with a superb high-voltage window of 4.7 V.In addition,the designed electrolyte also exhibits obviously improved thermal stability with no deformation at 120°C for 5 min.Furthermore,the semi-solid NCM811||Li batteries exhibit a favourable capacity retention of 88.8%after 150 cycles at 0.5 C.Even assembled with NCM622 cathode working at 4.5 V,the semi-solid batteries can still show a satisfactory capacity retention of 85.3%after 100 cycles at 0.5 C.Also,a 0.1 Ah NCM811||Li pouch cell with active materials loading of 9 mg/cm2 demonstrates satisfactory cycling stability and working ability,which shows promising practical application prospects.
基金supported in part by the National Institute of Environmental Health Sciences(Z01ES102745 to GH).
文摘Eukaryotic mRNAs are polyadenylated at their 3’-ends,and the poly(A)tails play critical roles in post-transcriptional gene regulation by influencing mRNA stability and translation.Here,we describe the biological processes and major protein factors that control poly(A)tail synthesis and shortening.We also discuss recent breakthroughs in poly(A)tail sequencing methods that enable high throughput and accurate measurement of poly(A)tail lengths.Finally,we review how poly(A)-tail regulators and poly(A)-tail-mediated post-transcriptional mechanisms affect stem cell fate and early embryonic development.
基金supported by the Project of the National Science Foundation of China(Nos.52173033,51773044 and 51603047)Foshan Science and Technology Innovation Project(No.FS0AA-KJ919-4402-0145)。
文摘Although amide-and hydrazide-based nucleating agents have been extensively used to enhance the crystallization performance of poly(lactic acid)(PLA),structurally similar nucleating agents exhibit significant differences in their crystallization-promoting efficiency,and the underlying mechanism remains unclear.In this study,a series of nucleating agents,including N,N-diphenylterephthalamide(DPTA),N,N,N-triphenyl-1,3,5-benzenetricarboxamide(TPTA),N,N-diphenyl terephthalohydrazide(DBTA),and N,N,N-tribenzoyl-1,3,5-benzenetricarbohydrazide(TBTA),were designed and synthesized to investigate the differences in their effects on the crystallization performance of PLA.Density functional theory(DFT)and molecular dynamics(MD)simulations showed that DBTA had a smaller electrostatic potential difference(66.2 kcal/mol).During the cooling process,DBTA could stably form more intermolecular hydrogen bonds with PLA and exhibit a higher interaction energy,thus theoretically enabling more efficient promotion of PLA crystallization.Further differential scanning calorimetry(DSC)results revealed that at a 0.5wt%loading of DBTA,the crystallization peak temperature of the PLA-DBTA composite reached 118.1℃during cooling,whereas no distinct crystallization peak was observed for pure PLA under identical conditions.The crystallinity of the composite was significantly increased to 58.4%compared to 14.6%of pure PLA.Moreover,under isothermal crystallization at 130℃,DBTA reduced the half-crystallization time of PLA to 2.9min,while the half-crystallization time for pure PLA was 27.4 min.Time-resolved Fourier transform infrared spectroscopy(FTIR)results also confirmed that DBTA promoted the formation of gt conformational isomers of PLA during the crystallization process.This study elucidates the mechanism behind the performance differences between structurally similar nucleating agents in regulating PLA crystallization from the perspective of molecular electrostatic potential and hydrogen bonding interactions,providing a theoretical basis for the molecular design of efficient nucleating agents.
文摘The introduction of high-k/metal gate(HK/MG)technology enables independent tuning of N-type metal-oxide-semi-conductor(NMOS)and P-type metal-oxide-semiconductor(PMOS)threshold voltages,facilitating advanced nodes and improv-ing overall chip performance.However,severe pattern loading effects during PMOS device fabrication pose challenges in dummy poly removal.This work reports the optimization of the photoresist etch back(PREB)process,providing a wider pro-cess window for subsequent AL CMP.By tuning the PR coating uniformity to 1.6%and applying four-zone electrostatic chuck(ESC)temperature control,the wafer-level uniformities of PR,SiN,and SiO_(2)were reduced to 6.3%,2.3%,and 5.1%,respectively.An optimized over etch(OE)recipe with a high selectivity of PR:SiN:SiO_(2)≈1:1:6 effectively balanced gate height loading between N-and PMOS regions.Furthermore,precise EB1 time tuning enabled defect removal,while advanced KLA inspection ensured early detection of critical failure modes.Collectively,these measures establish a robust and stable PREB process for advanced logic device fabrication.
基金supported through RIIM Competition funding from the Indonesia Endowment Fund for Education Agency,Ministry of Finance of the Republic of Indonesia and National Research and Innovation Agency of Indonesia according to the contract number:61/IV/KS/5/2023 and 2131/UN6.3.1/PT.00/2023.
文摘Corn starch(CS)is a renewable,biodegradable polysaccharide valued for its film-forming ability,yet native CS films exhibit lowmechanical strength,highwater sensitivity,and limited thermal stability.This study improves CS-based films by blending with poly(vinyl alcohol)(PVA)or glycerol(GLY)and using citric acid(CA)as a green,non-toxic cross-linker.Composite films were prepared by casting CS–PVA or CS-GLY with CA at 0%-0.20%(w/w of starch).The influence of CA on physicochemical,mechanical,optical,thermal,and water barrier properties was evaluated.CA crosslinking markedly enhanced the tensile strength,water resistance,and thermal stability of CS-PVA films while increasing transparency in CS–GLY films.At 0.20%CA,the composite achieved 34.99MPa tensile strength,reducedwater vapor permeability,andminimized water uptake.FTIR confirmed ester bond formation between CAand hydroxyl groups of CS,PVA,and GLY,whereas thermal analysis showed higher decomposition temperatures and lower weight loss in crosslinked films.Increasing CA levels also decreased opacity and improved light transmittance,indicating greater homogeneity and reduced crystallinity.This dual-polymer matrix combined with a natural crosslinking strategy provides a sustainable route to high-performance,biodegradable CS-based packaging materials.
基金financially supported by the National Key Research and Development Program of China(Nos.2022YFC2603500,2022YFC2603502)the Guangzhou Science and Technology Project(No.2024A04J4280).All authors acknowledge the financial support.
文摘Silica aerogels(SAs)impart low density and excellent thermal insulation to polymer systems,yet incorporating hydrophobic SAs into aqueous rubber latex systems remains challenging owing to their poor dispersibility and potential to destabilize the latex.Although previous studies have dispersed SAs in aqueous poly(vinyl alcohol)(PVA),the stability of such dispersions and their effectiveness as bridging media for latex integration have not been thoroughly evaluated,which limits their practical application in latex compounding.This study systematically examined how the surface chemistry governs hydrolytic stability,interfacial behavior,and latex compatibility in PVA-assisted aqueous processing.Two hydrophobic SAs were prepared:ethoxy-modified SA(E-SA)and methyl-modified SA(M-SA).Both initially formed a homogeneous PVA slurry,but E-SA rapidly hydrolyzed its surface—OCH_(2)CH_(3)groups,releasing ethanol,becoming hydrophilic,and undergoing irreversible nanopore collapse.In contrast,M-SA maintains its structural integrity and hydrophobicity because its—Si(CH_(3))_(3)groups are highly resistant to hydrolysis.This divergence dictates the behavior during latex blending.The ethanol released from E-SA disrupts electrostatic and steric stabilization,inducing latex coagulation,whereas M-SA/PVA dispersions preserve colloidal stability across diverse latex systems.As a practical demonstration,M-SA-reinforced chlorosulfonated polyethylene(CSM)rubber latex composites show more than a 50%reduction in thermal conductivity while maintaining chemical resistance,enabling high-performance insulating protective gloves and coatings.This work establishes a critical link between aerogel surface chemistry and aqueous processing stability,providing a mechanistic foundation for the rational design of water-based rubber/silica aerogel composites and next-generation thermal insulation materials.
基金the“Pioneer”and“Leading Goose”R&D Program of Zhejiang(No.2023C01072)the Institute of Zhejiang University-Quzhou for their financial support。
文摘Poly(phenylene oxide)(PPO)exhibits excellent dielectric properties,making it an ideal substrate for high-frequency,high-speed copper-clad laminates.The phenolic hydroxyl group at the end of PPO plays a key role in its reactivity.Accurately quantifying the phenolic hydroxyl content in PPO is essential but challenging.In this study,we proposed a method for measuring the phenolic hydroxyl content of PPO using differential UV absorption spectroscopy.In alkaline solutions,the phenolic hydroxyl in PPO completely ionizes to form phenoxide ions,leading to a significant increase in UV absorbance at approximately 250 and 300 nm.Notably,the differential UV absorbance at approximately 300 nm was directly proportional to the phenolic hydroxyl concentration.Using 2,6-dimethylphenol as a standard,a calibration curve was established to relate the phenolic hydroxyl concentration to differential UV absorbance at approximately 300 nm,providing a precise and straightforward method for phenolic hydroxyl quantification in PPO with distinct advantages over conventional techniques.
基金supported by the National Natural Science Foundation of China(No.51905543)。
文摘This study aimed to systematically regulate the performance of 4D printing composites by investigating the synergistic effects of dicumyl peroxide(DCP)and maleic anhydride-grafted polyethylene(MAH-g-PE)on a poly(lactic acid)/thermoplastic polyurethane(PLA/TPU)matrix.Specifically,using a 70 wt%/30 wt%PLA/TPU matrix and an L_(9)(3^(2))orthogonal design,composites were evaluated via morphology,shape memory,mechanical tests,and multi-criteria analysis.Moderate DCP enhanced crosslinking,improving storage modulus and thermal stability,while excessive DCP caused brittleness.Furthermore,MAH-g-PE effectively improved interfacial compatibility,and its synergy with DCP was dosage-dependent.Consequently,Sample 5 achieved optimal performance,exhibiting uniform fracture morphology,a shape fixation rate of98.8%with the fastest recovery,and balanced strength-ductility.Multi-criteria analysis identified elongation at break and recovery time as the top contributing factors,with consistent rankings validated by Spearman analysis(ρ=0.833,p<0.01).In summary,adjusting DCP and MAH-g-PE contents effectively modulates the crosslinking structure and interfacial properties of PLA/TPU composites,providing a viable strategy for developing high-performance,tunable 4D printing materials.
基金financially supported by the National Natural Science Foundation of China(Nos.52263010 and 52372188)2023 Introduction of studying abroad talent program,Henan Provincial Key Scientific Research Project of Collegesand Universities(No.23A150038)+1 种基金Key Scientific Research Project of Education Department of Henan Province(No.22A150042)the National students'platform for innovation and entrepreneurship training program(No.201910476010).
文摘Thermoplastic polyurethane(TPU)consists of a hardsegment and a soft segment,where the former affords mechanical strength and thermalstability,while the latter provides a possibility of good ionic conductivity by promoting dissociation of ions from the lithium salt.Thus,TPU attracts a wide interest recently as a promising polymer electrolyte for solid-state lithium batteries.However,the relatively low ionic conductivity of TPU still restricts its actual applications due to the aggregation of polymer chains,which greatly reduces the dissociation of lithium salts.Herein,a strategy to address this challenge was adopted by in situ polymerization poly(ethylene glycol diacrylate)(PEGDA)in fully dispersed TPU.Hence a stretchable solid-state electrolyte(denoted as TELL and the contrast sample was denoted as TLL)with high ionic conductivity of 7.18×10^(-4) S/cm was obtained at room temperature.The Li^(+)transference number is 0.85 in Li|TELL|Li cell and can stably undergo charge-discharge cycles for 1400 h at a current density of 0.1 mA/cm^(2),while the contrast sample is short-circuited after 634 h of cycling.The LiFePO_(4)|TELL|Li cell achieves a capacity retention of 78.93%after 200 cycles at 2 C.The LiFePO_(4)|TLL| Li cellonly gains the capacity retention of 51.9%after 50 cyclesat the same current density.So,the method adopted here may provide a new approach to realize a flexible solid-state electrolyte with high ion-conductivity.
