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In order to further enhance the erosion resistance of cement concrete pavement materials, this study constructed an apparent rough hydrophobic structure layer by spraying a micro-nano substrate coating on the surface layer of the cement concrete pavement. This was followed by a secondary spray of a hydroxy-silicone oil-modified epoxy resin and a low surface energy-modified substance paste, which combine to form a superhydrophobic coating. The hydrophobic mechanism of the coating was then analysed. Firstly, the effects of different types and ratios of micro-nano substrates on the apparent morphology and hydrophobic performance of the rough structure layer were explored through contact angle testing and scanning electron microscopy (SEM). Subsequently, Fourier transform infrared spectroscopy and permeation gel chromatography were employed to ascertain the optimal modification ratio, temperature, and reaction mechanism of hydroxy-silicone oil with E51 type epoxy resin. Additionally, the mechanical properties of the modified epoxy resin-low surface energy-modified substance paste were evaluated through tensile tests. Finally, the erosion resistance of the superhydrophobic coating was tested under a range of conditions, including acidic, alkaline, de-icer, UV ageing, freeze-thaw cycles and wet wheel wear. The results demonstrate that relying solely on the rough structure of the concrete surface makes it challenging to achieve superhydrophobic performance. A rough structure layer constructed with diamond micropowder and hydrophobic nano-silica is less prone to cracking and can form more "air chamber" structures on the surface, with better wear resistance and hydrophobic performance. The ring-opening reaction products that occur during the preparation of modified epoxy resin will severely affect its mechanical strength after curing. Controlling the reaction temperature and reactant ratio can effectively push the modification reaction of epoxy resin through dehydration condensation, which produces more grafted polymer. It is noteworthy that the grafted polymer content is positively correlated with the hydrophobicity of the modified epoxy resin. The superhydrophobic coating exhibited enhanced erosion resistance (based on hydrochloric acid), UV ageing resistance, abrasion resistance, and freeze-thaw damage resistance to de-icers by 19.41%, 18.36%, 43.17% and 87.47%, respectively, in comparison to the conventional silane-based surface treatment. [ABSTRACT FROM AUTHOR]

The stable and safe operation of highway/railway lines is largely dependent on the dynamic behavior of subgrade fillings. Clay soils are widely used in subgrade construction and are compacted at different remolding water contents and compaction degrees, depending on the field conditions. As a result, their dynamic behaviors may vary, which have not been fully investigated until now. To clarify this aspect, a series of cyclic triaxial tests were carried out in this study with three typical remolding water contents (w = 19%, 24%, and 29%), corresponding to the optimum water content as well as its dry and wet sides, and two compaction degrees (Dc = 0.8 and 0.9), which were selected according to the field-testing data. Scanning electron microscopy (SEM) and mercury intrusion porosimetry (MIP) tests were also conducted on typical samples to investigate the corresponding soil fabric variations. The findings indicate the following: (a) The soil fabric at the optimum remolding water content and its dry side was characterized by a clay aggregate assembly with a bimodal pore size distribution. In contrast, the soil fabric on the wet side of the optimum water content consisted of dispersed clay particles with a unimodal pore size distribution. (b) As the compaction degree increased, to ensure the optimum water content and its dry side, large pores were compressed to make them smaller, while small pores remained unchanged. Comparatively, all the pores on the wet side were compressed to make them smaller. (c) For each compaction degree, as the remolding water content increased, a non-monotonic changing pattern was identified for both the permanent strain and resilient modulus; the permanent strain first decreased and then increased, while, for the resilient modulus, an initial increasing trend and then a decreasing trend were identified. In addition, a larger changing rate of the permanent strain (resilient modulus) was observed on the dry side, indicating a larger effect of the remolding water content. (d) For each remolding water content, as the compaction degree increased, the permanent strain exhibited a decreasing trend, but an increasing trend was identified for the resilient modulus. Moreover, the rate of change in the permanent strain (resilient modulus) on the dry side of the optimum water content was larger than that on the wet side. In contrast, the minimum rate of change was identified at the optimum water content. The obtained results allowed for the effects of the remolding water content and compaction degree on the dynamic behavior to be analyzed, and they helped guide the construction and maintenance of the subgrade. [ABSTRACT FROM AUTHOR]

Traditional epoxy resins are of technological significance for structural adhesives and composite materials, as well as many others. However, brittleness limits its further development, and achieving a combination of toughness and rigidity in epoxy networks remains a great challenge. In this work, we designed and synthesized low-temperature curable, tough and repairable epoxy networks via hindered urea bond (HUB) crosslinking strategies. Mechanical testing revealed that the material exhibited simultaneously improved toughness and stiffness, and specifically, tensile strength, elongation at break, and toughness were able to reach 78.2 MPa, 8.61%, and 4.63 MJ · m−3, respectively. More importantly, the dynamic exchange of HUB dispersed between polymer chains enables HUB crosslinked epoxy with thermal-triggered reparability and recyclability. In addition, thermal properties, chemical stability and water resistance of toughened epoxy samples were also characterized. This work provides a practical guidance for the exploration of high-performance epoxy with the potential to be extended to other polymers. [ABSTRACT FROM AUTHOR]

This study utilized transmission electron microscopy (TEM) and on-axis transmission Kikuchi diffraction (TKD) to investigate the fatigue-induced HCP-to-FCC phase transformation in industrial pure zirconium under a stress ratio of R = 0.1. The results show that fatigue damages result from phase deformations during cyclic loadings. The fatigue-induced FCC-Zr phases exhibit a B-type orientation relationship with the HCP-Zr matrix. Notedly, due to the different growth directions of Shockley partial dislocations relative to nucleation points, there are two FCC-Zr variants after the HCP-to-FCC phase transformation. The content of these two variants accounts for 65% and 35% of the total FCC-Zr, respectively, appearing as lamellae morphology embedded parallelly within the matrix. The distribution of the two variants includes isolated distribution and adjacent distribution. For the adjacent distribution, a twinning relationship is observed between the two variants. Meanwhile, as an intermediate transition stage of the HCP-to-FCC phase transformation, stacking faults are observed at the boundaries of the FCC-Zr lamellae. These findings offer insights into the microstructural features and formation mechanisms of fatigue-induced HCP-to-FCC phase transformation.

ObjectiveBased on the theory of planned behavior, this study introduced personality traits and exercise-induced feelings and other third variables, aiming to explore the mechanism of personality traits and exercise-induced feelings between exercise intention and exercise behavior, and explore the internal mechanism of promoting exercise behavior of junior high school students.MethodsThis research adopts the Exercise Intention Questionnaire, Simple Big Five Personality Scale, Exercise-induced Feeling Inventory and Exercise Rating Scale, from the three cities of Anhui province 1,166 junior high school students selected from the group psychological measurement, and uses the SPSS23.0 and Process plug-in exercise intention in exercise behavior analysis of the direct and indirect effect.ResultsThe results showed that: (1) Exercise intention significantly positively predicted exercise behavior (β = 0.265, t = 4.261, p

ObjectiveThis study explores the relationship between physical exercise and school adaptation of junior middle school students and constructs a chain intermediary model through the intermediary role of psychological resilience and sports learning motivation.MethodsUsing the stratified cluster sampling method, 930 junior middle school students in Anhui Province were measured in group psychology by using the physical exercise rating scale, adolescent psychological resilience scale, physical learning motivation scale and school adaptation scale. The statistical software SPSS 23.0 and process plug-in were used for statistical processing, and the common method deviation test was carried out by Harman single-factor control method. Finally, the bootstrap sampling test method and process plug-in were used to test the significance of intermediary effect.Results(1) The direct prediction effect of physical exercise on school adaptation is remarkable (t = 4.60, p

ObjectiveThis study explores the relationship between exercise intention and exercise behavior and constructs a chain mediating model through the mediating effect of implementation intention and self-identity.MethodThrough the stratified cluster sampling method, 1,573 junior school students (with an average age of 13.71 ± 0.891 years) were evaluated by the exercise intention scale, the implementation intention scale, the self-identity scale, and the physical exercise grade scale. For data analysis, the common method deviation test, Pearson correlation analysis, and Model 6 in the SPSS macro program compiled by Hayes for the chain mediating test were conducted.Results(1) There is a marked correlation between positive exercise intention and exercise behavior (r = 0.345, p < 0.01), and exercise intention has a significant effect on the direct path of exercise behavior (β = 0.162, t = 12.355, p < 0.01). (2) Exercise intention can positively predict implementation intention (β = 0.219, t = 10.006, p < 0.01) and self-identity (β = 0.160, t = 16.159, p < 0.01); implementation intention can significantly and positively predict exercise behavior (β = 0.230, t = 12.742, p < 0.01),and self-identity can significantly and positively predict exercise behavior (β = 0.273, t = 7.911, p < 0.01). (3) Implementation intention and self-identity play a significant mediating role between exercise intention and exercise behavior. The mediating effect consists of three indirect effects: exercise intention → implementation intention → exercise behavior (the mediating effect value is 0.050), exercise intention → self-identity → exercise behavior (the mediating effect value is 0.044), and exercise intention →implementation intention → self-identity → exercise behavior (the mediating effect value is 0.017).Conclusion(1) Exercise intention can significantly and positively predict exercise behavior. (2) Implementation intention and self-identity exert a significant mediating effect between exercise intention and exercise behavior, including the separate mediating effect of implementation intention and self-identity, as well as the chain mediating effect of implementation intention and self-identity.

Chemotherapy is currently one of the most widely used treatments for cancer. However, traditional chemotherapy drugs normally have poor tumor selectivity, leading to insufficient accumulation at the tumor site and high systemic cytotoxicity. To address this issue, we designed and prepared a boronic acid/ester-based pH-responsive nano-drug delivery system that targets the acidic microenvironment of tumors. We synthesized hydrophobic polyesters with multiple pendent phenylboronic acid groups (PBA-PAL) and hydrophilic PEGs terminated with dopamine (mPEG-DA). These two types of polymers formed amphiphilic structures through phenylboronic ester linkages, which self-assembled to form stable PTX-loaded nanoparticles (PTX/PBA NPs) using the nanoprecipitation method. The resulting PTX/PBA NPs demonstrated excellent drug encapsulation efficiency and pH-triggered drug-release capacity. In vitro and in vivo evaluations of the anticancer activity of PTX/PBA NPs showed that they improved the pharmacokinetics of drugs and exhibited high anticancer activity while with low systemic toxicity. This novel phenylboronic acid/ester-based pH-responsive nano-drug delivery system can enhance the therapeutic effect of anticancer drugs and may have high potential for clinical transformations.

Piezoelectric impedance sensing is promising for highly accurate damage identification because of its high-frequency active interrogative nature and simplicity in data acquisition. To fully unleash the potential, effective inverse analysis is needed in order to pinpoint the damage location and identify the severity. The inverse analysis, however, may be underdetermined since there exists a very large number of unknowns (i.e., locations and severity levels) to be solved in a finite element model but only limited measurements are available in actual practice. To uncover the true damage scenario, an inverse analysis strategy built upon the multi-objective optimization, which aims at matching the multiple sets of measurements with model predictions in the damage parametric space, can be formulated to identify a small set of solutions. This solution set then allows the incorporation of empirical knowledge to facilitate final decision-making. The main disadvantage of the conventional inverse analysis strategy is that it overlooks uncertainties that exist in both baseline structural modeling and actual measurements. To address this, in this research, we formulate a probabilistic multi-objective optimization-based inverse analysis framework, which is fundamentally built upon the differential evolution Markov chain Monte Carlo (DEMC) technique. The new approach can yield the Pareto optimal set (solutions) and the respective Pareto front, which are represented in a probabilistic sense to account for uncertainties. Comprehensive case studies with experimental investigations are conducted to demonstrate the effectiveness of this new approach.

Aggregate stability is considered an essential indicator of changes in the physical properties of soils, and vegetation roots play a crucial role in the stability of shallow soil aggregates in ionic rare earth tailings piles during ecological remediation. In this paper, the influence of the law of ecologically restored vegetation roots on the stability of shallow aggregates of ionic rare earth tailing piles was investigated by means of field investigation tests, indoor experiments and mathematical statistics. The influence of different types of root systems on the stability of the shallow depth range aggregates of tailings piles was investigated; the correlation between vegetation root systems and the main physical parameters of rare earth tailings was clarified; and a mathematical correlation model characterizing the characteristic parameters of vegetation root systems was constructed. The evaluation index of the stability of rare earth tailings piles was constructed, and the influence of the law of the ecological restoration of vegetation root systems on the strength of shallow aggregates of ionic rare earth tailings piles was revealed. The results of the study showed that compared with the RD (root density), the root characteristic parameter with the largest response weight to the rare earth tailings pile is the RL (root length density), and the root characteristic parameter with the largest response weight to the water content is the RV (root volume). Suitable vegetation roots can effectively enhance the content of shallow large aggregates of rare ionic earth tailing piles. With the increase of the depth of a tailing pile, the content of large aggregates continues to decrease, and the content of micro aggregates continues increasing. This indicates that the vegetation root system changed the shallow soil of the rare earth tailing pile from disorderly to orderly through its own growth pattern, which effectively improved the stability of the shallow aggregates of the tailing pile and improved the physical properties of the tailing.

A variable coefficient segmented iron loss calculation model is proposed for high‐voltage multi‐pole asynchronous motors, which fully considers the influence of high‐order harmonic magnetic density on such motors. This model introduces additional hysteresis loss, improved eddy current loss coefficients, and rotation magnetisation coefficients to account for changes in losses due to small hysteresis loops and skin effect, as well as rotation magnetisation losses. A 710 kW 10‐pole asynchronous motor is used as the research object. A full‐domain iron loss calculation model considering stator and rotor tooth top surface losses is developed. The model can be used to accurately calculate the overall and local harmonic iron losses in the stator and rotor cores of high‐voltage multi‐pole asynchronous motors. And quantitatively analyse the distribution pattern of any harmonic iron loss at any location in the motor core. It realises the refinement calculation and analysis of iron losses in the whole domain of high‐voltage multi‐pole asynchronous motor. Finally, no‐load and load tests were conducted on the 710 kW 10‐pole asynchronous motor. The iron losses of the 710 kW 10‐pole asynchronous motor at no load and load are calculated using the above mentioned model and the classical trinomial constant factor model. The results are compared with the measured iron loss values. It is proved that the iron loss model is more accurate in calculating the iron loss of high‐voltage multi‐pole asynchronous motor. The result helps researchers to calculate the iron loss distribution of high voltage motors more accurately. Thus, the design and operating parameters of the motor can be optimised to improve the efficiency and performance of the motor. It provides the necessary technical support and key basis for the reduction of loss and energy saving of high‐voltage motors and the optimisation of their core structure. [ABSTRACT FROM AUTHOR]

Intrinsic self-healing waterborne polyurethane (WPU) is an environmentally friendly, economically viable, and practical novel intelligent material. However, the key to achieving practical applications lies in the remote activation of repair in self-healing materials and the excellent mechanical properties of the matrix. In this study, we introduce quadruple hydrogen bonding in the polyurethane backbone. We have incorporated a novel two-dimensional sheet-like material, MXene, to achieve visible light remote-driven self-healing of material hydrogen bonds while enhancing the material’s mechanical properties. By utilizing the MXene supernatant, this approach not only resolves the issues of poor stability and easy sedimentation of MXene nanosheets in water-based polymers but also helps to prevent resource wastage. Our research results demonstrate that the composite film exhibits a tensile strength of 6.55 MPa and a fracture elongation of 604%. Additionally, quadruple hydrogen bonds in the WPU chains enable rapid self-healing of microcracks under visible light irradiation at 300 mW/cm2, with complete disappearance within 80 min. [ABSTRACT FROM AUTHOR]

This study aims to explore the relationship between physical exercise (PE), self-control (SC), physical exercise atmosphere (PEA), and mobile phone addiction tendency (MPAT) among Chinese university students. Through the quota sampling, 1,433 students complied with the requirements were surveyed from 10 universities in China. PE, SC, PEA, and MPAT were assessed using standard scales. For data analysis, common method deviation test, mean number, standard deviation, correlation analysis and structural equation model analysis were carried out in turn. The results showed PE and MPAT were negatively related (r = –0.158, p < 0.05); PE significantly positively predicted SC (β = 0.082, t = 3.748, p < 0.01), and SC significantly negatively predicted MPAT (β = –0.743, t = –19.929, p < 0.01). Bootstrap method was used to test the mediating effect of SC. The results showed that 95% confidence interval did not include 0. After adding the mediating variable of SC, PE did not significantly negatively predict the tendency of MPAT (β = –0.027, t = –1.257, p > 0.05). The interaction item PEA and SC could significantly positively predict the tendency of MPAT (β = 0.165, t = 2.545, p < 0.05). In the high PEA group, SC had a significant negative predictive effect on the tendency of MPAT (β = –0.665, t = –14.408, p < 0.01); However, in the low PEA group, the negative predictive effect was stronger (β = –0.834, t = –15.015, p < 0.01). The present study shows that PE significantly negatively predicted the tendency of MPAT, and SC played a complete mediating role in the relationship between PE and MPAT; The second half of the indirect effect of PE and MPAT was regulated by the PEA. The PEA will enhance the influence of SC on MPAT, but the high PEA will increase the level of MPAT of individuals at a very high level of SC.

Objective: This study aimed to contribute to understanding the mechanisms underlying the association between empowering motivational climate in physical education and social responsibility among high school students, and have important implications for interventions aimed at improving social responsibility among high school students.Methods: Through the quota sampling, 802 students (average age = 17 years, SD = 0.97 years) that complied with the requirements were surveyed from Anhui Province in China. Empowering motivational climate in physical education, social responsibility, interpersonal disturbance, and general self-efficacy were assessed using standard scales. For data analysis, Pearson’s correlation analysis, structural equation model test, and bias-corrected percentile Bootstrap method were carried out in turn.Results: (1) Common method biases can be accepted in this study, and the correlation among empowering motivational climate in physical education, social responsibility, interpersonal disturbance, and general self-efficacy are all significant; (2)Empowering motivational climate in physical education, interpersonal disturbance and general self-efficacy can all predict social responsibility significantly; (3) Structural equation modeling indicates good fit: χ2/df = 2.86, RMESA = 0.068, CFI = 0.92, NNFI = 0.91, NFI = 0.90, GFI = 0.93. It indicates that interpersonal disturbance and general self-efficacy can play mediating roles between empowering motivational climate in physical education and social responsibility, respectively. After that, interpersonal disturbance as well as general self-efficacy in turn plays the chain mediating effect in the relationship between empowering motivational climate in physical education and social responsibility. The effect size of the mediating effect of interpersonal disturbance and general self-efficacy in the relationship between empowering motivational climate in physical education and social responsibility is 0.048 and 0.148, respectively, and the effect size of the chain mediating effect is 0.031.Conclusion: Empowering motivational climate in physical education not only has a direct effect on social responsibility among high school students, but also influences social responsibility by the chain mediating effect of interpersonal disturbance and general self-efficacy.

Simple Summary: In the context of large-scale production, it is necessary to improve ewes health status and reproductive performance to promote newborns survival rate and later fattening performance. Previous studies have indicated that phenolic acids could change the host rumen microflora and inhibit pathogenic bacteria to ensure rumen health and host body health. However, there are few studies on isochlorogenic acid (ICGA) in ruminants. Therefore, based on regulating the rumen environment of breeding ewes during the whole physiological period, the experiment was conducted to study the effects of ICGA on rumen fermentation, microbial diversity and immunity of ewes at estrus, pregnancy and lactation stages. The experimental data obtained showed that adding ICGA could regulate ewes rumen fermentation mode, optimize microbial flora of different physiological stages by increasing Bacteroidota relative abundance while reducing Firmicutes relative abundance, maintain rumen microbial homeostasis at the pregnancy stage, and increase ewes blood immuneglobulin content, thereby improving ewes health. The effects of isochlorogenic acid (ICGA) on ewes rumen environment, microbial diversity, and immunity at different physiological stages (estrus, pregnancy and lactation) were studied in this experiment. Twenty healthy female Hu lambs of 1.5 months with similar body weight (17.82 ± 0.98 kg) and body condition were selected and randomly divided into two groups: the control group (CON) and the ICGA group (ICGA). The lambs of CON were fed a basal diet, while the lambs of ICGA were supplemented with 0.1% ICGA based on the basal diet. Lambs rumen fermentation characteristics, microbial diversity and immunity at estrus, pregnancy, and lactation stages were determined and analyzed, respectively. The results showed that the rumen pH in CON increased first and then decreased as lambs grew (p < 0.05). However, it showed the opposite change in ICGA. The content of ammonia nitrogen (NH3-N) showed the highest at estrus stage in both groups, but it was significantly higher in ICGA than that in CON (p < 0.05). The Acetic acid/propionic acid (A/P) ratio at estrus stage and the volatile fatty acids (VFAs) at pregnancy stage in ICGA were significantly higher than those of the CON (p < 0.05). The 16S rDNA sequencing analysis showed that the Shannon, Chao 1 and ACE indexes of the ICGA were significantly higher than those of the CON both at estrus and lactation stages (p < 0.05), while they showed higher at the pregnancy stage in CON (p > 0.05). Principal component analysis (PCA) showed that there were significant differences in rumen microorganism structure between CON and ICGA at all physiological stages (p < 0.01). At the phylum level, compared with the CON, Firmicutes relative abundance of three physiological stages decreased (p > 0.05) while Bacteroidota increased (p > 0.05). The relative abundance of Synergistota at estrus stage and Patescibacteria at the lactation stage increased significantly too (p < 0.05). At the genus level, compared with the CON, the relative abundance of Prevotella at three stages showed the highest (p > 0.05), while the relative abundance of Succiniclasticum, unclassified_Selenomonadaceae and Rikenellaceae_RC9_gut_group showed different abundances at different physiological stages in ICGA. Compared with the CON, the lambs of the ICGA showed higher blood IgG, IgM, and TNF- α contents at three physiological stages and higher IL-6 contents at pregnancy stage (p < 0.05). Conclusion: Adding ICGA could regulate ewes rumen fermentation mode at different physiological stages by increasing rumen NH3-N at estrus, VFAs at pregnancy, and the ratio of A/P at lactation. It optimizes rumen microbial flora of different physiological stages by increasing Bacteroidota relative abundance while reducing Firmicutes relative abundance, maintaining rumen microbial homeostasis at pregnant stage, increasing the number of beneficial bacteria in later lactating and ewes blood immunoglobulins content at three physiological stages. [ABSTRACT FROM AUTHOR]

In order to investigate the effect of plant protection measures on the improvement of the soil in semi-arid wind-sand grassland area, the plant protection system of Chagannur Salt Lake was used as the research object, and the physical and chemical properties of the soil in different areas were measured by the method of field investigation combined with indoor experiment, and the changes of soil salinity, soil pH, soil particle size composition, soil organic matter and nitrogen, phosphorus and potassium content in 0-30 cm depth were analyzed. The results showed that,20 years after the construction of the plant protection system in Chagannur Salt Lake, the initial highly saline and alkaline soil environment had changed significantly under the synergistic effect of the protection zone to block wind erosion materials and plants to improve the soil. Compared with the dried lake center, the pH of each site in the plant protection system decreased to different degrees, and the soil salinity in the alkaline shield decreased by 75.34%; the clay and powder content of the soil in the alkaline shield increased significantly, increasing by 51.60% and 22.14% respectively compared with the dried lake center, and the coarse sand content decreased by 72.06% compared with the dried lake center.The contents of quick-acting potassium, quick-acting phosphorus and organic matter of the soil in the alkaline shield were the highest, which were 86%, 39% and 55% of the dry lake center, respectively. The quick-acting nitrogen content of white thorn bushes in the transition zone was the highest, which was 28% of the dry lake center. Overall each nutrient content showed a significant correlation (P<0.05) with clay and powder grains. After 20 years of construction, the content of quick-acting potassium, quick-acting phosphorus and organic matter of the soil in the alkali plant protection zone had increased significantly compared with that at the beginning of the construction period, indicating that the plant protection system has a significant improvement effect on the soil. The research results could provide data support for the evaluation of the protective effect of the plant protection system in the salt lake, and could provide scientific basis for the control of wind erosion and regional vegetation restoration and reconstruction of the dry salt lake in the semi-arid sandy steppe area. [ABSTRACT FROM AUTHOR]

Polyethylenimine (PEI) has been widely used in gene delivery. However, its high cytotoxicity and undesired non-specific protein adsorption hinder the overall delivery efficacy and the practical applications of PEI-based gene delivery systems. In this study, we prepared hydrophobically modified PEIs (H-PEIs) via the reaction of octanal with 40% of primary amines in PEI25k and PEI10k, respectively. Two common zwitterionic molecules, 1,3-propanesultone and β-propiolactone, were then used for the modification of the resulting H-PEIs to construct polycationic gene carriers with zwitterionic properties (H-zPEIs). The siRNA delivery efficiency and cytotoxicity of these materials were evaluated in Hela-Luc and A549-Luc cell lines. Compared with their respective parental H-PEIs, different degrees of zwitterionic modification showed different effects in reducing cytotoxicity and delivery efficiency. All zwitterion-modified PEIs showed excellent siRNA binding capacity, reduced nonspecific protein adsorption, and enhanced stability upon nuclease degradation. It is concluded that zwitterionic molecular modification is an effective method to construct efficient vectors by preventing undesired interactions between polycationic carriers and biomacromolecules. It may offer insights into the modification of other cationic carriers of nucleic acid drugs.

This study presents a full-scale model investigation on variations of soil stress in a geosynthetic-reinforced pile- supported track bed at various water levels and loading cycles, with four testing procedures: water level rising, cyclic loading at high water level, water level lowering, and cyclic loading at low water level. The soil arching effect was revealed, characterized by higher stress above the pile cap. With the water level rising and loading cycles increasing at high water level, this effect becomes more pronounced, until a peak value of dynamic stress concentration ratio is reached. The stable state of soil arching is obtained earlier near the crown of soil arching, but this arching effect develops more significantly at the foot of soil arching. With the water level lowering and loading at low water level, the soil arching effect remains steady, with slightly changed dynamic stresses in the track bed. The geogrid shows a significant impact on the load transfer mechanism for the quasi- static stress: the quasi-static pile-cap stress presents higher values below the geogrid, whereas the opposite trend is observed for the water-bag (subsoil) area. Nevertheless, this mechanism is not obvious with respect to the dynamic stress, with the values showing no distinct difference above and below the geogrid.Key words: geosynthetic-reinforced pile-supported track bed, water level, cyclic loading, soil arching, geogrid reinforcement.Cette etude presente une etude de modele grandeur nature sur les variations des contraintes du sol dans des plates-formes sur pieux renforcees par geosynthetique a differents niveaux d'eau et cycles de chargement, avec quatre procedures d'essai : elevation du niveau d'eau, chargement cyclique a niveau d'eau eleve, abaissement du niveau d'eau et chargement cyclique a niveau d'eau bas. L'effet de voute du sol a ete revele, caracterise par une contrainte plus elevee au-dessus du chapeau de pieu. Lorsque le niveau d'eau augmente et que les cycles de chargement augmentent a niveau d'eau elevee, cet effet devient plus prononce, 'usqu'a ce qu'une valeur maximale du rapport de concentration des contraintes dynamiques soit atteinte. L'etat stable des voutes du sol est obtenu plus tot pres du sommet de voute du sol, mais cet effet de voute se developpe de maniere plus significative au pied de voute du sol. Avec l'abaissement et le chargement du niveau d'eau a un niveau d'eau bas, l'effet de voute du sol reste stable, avec des contraintes dynamiques legerement modifiees dans la plate-forme de la voie. La geogrille montre un impact significatif sur le mecanisme de transfert de charge pour la contrainte quasi-statique : la contrainte quasi statique de chapeau de pieu presente des valeurs plus elevees sous la geogrille, tandis que la tendance inverse est observee pour la zone du sous-sol. Neanmoins, ce mecanisme n'est pas evident pour la contrainte dynamique, les valeurs ne montrant aucune difference nette au-dessus et en dessous de la geogrille. [Traduit par la Redaction]Mots-cles : plate-forme sur pieux renforcee par geosynthetique, niveau d'eau, chargement cyclique, effet de voute du sol, geogrille de renfort., IntroductionCompared to the track bed with subsoil improved by conventional methods, the geosynthetic-reinforced pile-supported (GRPS) track bed presents smaller accumulative settlement and is thus increasingly used in the new high-speed [...]