Search Results (34)

Carbon molecular sieve (CMS) membranes demonstrate considerable advantages and significant potential in the separation of CO₂ and CH₄. Nevertheless, current research predominantly emphasizes the enhancement of CMS membranes through the incorporation of rigid structures and chain spatial stacking. The role of flexible structures in this context remains inadequately understood. To address this gap, we introduced long-chain polydimethylsiloxane (PDMS) and copolymerized it to synthesize polyimide that combines rigid and flexible frameworks. This approach enabled us to investigate the impact of flexible structures on the structure and properties of carbon membranes by varying the PDMS content. The findings indicated that flexible PDMS significantly influenced the thermal decomposition behavior of polyimide and facilitated in situ silicon doping within the carbon membranes, thereby modifying the pore characteristics of the carbon film. Specifically, with a 10% addition of PDMS, the CO₂ permeability of the CMS membrane reached 9556 Barrer, representing an enhancement of 103.9% and surpassing the 2019 upper bound for CO₂/CH₄ separation. Furthermore, the effect of pyrolysis temperature was also examined. Ultimately, this study offers a novel perspective on regulating the structural and performance characteristics of carbon membranes through the integration of long-chain flexible structures. Full article

Farmer professional cooperatives are essential in promoting China’s rural revitalization. However, the widespread occurrence of “empty shell” cooperatives, which are characterized by operational stagnation and human resource depletion, presents significant challenges to achieving this objective. This study explores the role of award-rated demonstration cooperatives in addressing this issue by utilizing a unique dataset of 1570 cooperatives from a particular city in Guizhou Province. The analysis employs mediation and moderation effect models and identifies two primary mechanisms. First, the policy improves cooperatives’ access to government subsidies and loan facilities, which helps mitigate constraints related to human resources and operational risks. Second, cooperative characteristics, including member size, education levels, and leading entity, positively influence the effectiveness of these policy measures. Conversely, the equity structure shows a dual moderating effect, reducing policy benefits in resource retention while enhancing them in operational improvement. These findings highlight the intricate relationship between policy design and cooperative attributes in addressing structural inefficiencies and provide valuable insights for strengthening cooperative governance and advancing rural development. Full article

Candida utilis (CUM) possesses various biological effects, including anti-inflammatory, intestinal microbiota regulatory, and immunomodulatory activities. However, there has been little exploration regarding the effects of CUM on ulcerative colitis (UC). Therefore, this study aimed to investigate the beneficial effects of CUM on alleviating dextran sulfate sodium (DSS)-induced UC in mice and to explore the potential underlying mechanisms. Here, the effect of CUM on UC was analyzed using a DSS-induced colitis mouse model (n = 9), the results of which indicated a decrease in disease activity index (DAI) in DSS-induced UC mice. Furthermore, CUM alleviated colon shortening, minimized intestinal tissue damage, and preserved intestinal tight junction proteins (Claudin-3, Occludin, and ZO-1). CUM reduced the level of pro-inflammatory cytokines (IL-1β, IL-6, and TNF-α), inhibited the activation of the NF-ĸB, MAPK and PPARγ signaling pathways, and decreased the level of oxidative mediators (MPO, SOD and MDA) in the colon of UC mice. Additionally, it mitigated the dysbiosis of intestinal microbiota in UC mice by increasing the abundance of Prevotellaceae and Lactobacillus while decreasing the abundance of Bacteroidaceae and Enterobacteriaceae. CUM alleviated the decrease in short-chain fatty acids (SCFAs) content in the colon of UC mice. The above results provide a scientific basis for CUM, as a natural supplement, to restore the balance of the gut inflammatory microbiota and promote gut health. Full article

Understanding the dynamics of soil water content (SWC) is essential for effective land management, particularly in regions affected by underground mining. This study investigates the spatial and temporal patterns of SWC and its interaction with topographic and edaphic factors in coal mining and non-coal mining areas of the Chenghe watershed, located in the southeast of the Chinese Loess Plateau, which is divided by a river. Our findings revealed that the capacity to retain moisture in the top layer of coal mining areas is significantly higher (25.21%) compared to non-coal mining areas, although deeper layers exhibit lower SWC, indicating altered moisture dynamics due to underground mining disturbances. Coal mining areas show greater spatial and temporal variability in SWC, suggesting increased sensitivity to moisture fluctuations, which complicates water management practices. Additionally, underground mining activities introduce more intense effects on the relationship between SWC and topographic factors (i.e., GCVR across soil profile of 0–60 cm; slope at depth of 50 cm) or edaphic factors (i.e., soil organic matter and available potassium at depth of 30 cm; pH at depth of 50 cm) compared to non-coal mining areas. This variability is evident in the temporal shifts from positive to negative correlations, particularly in coal mining areas, reflecting modifications in both soil physical and chemical properties resulting from mining activities. In contrast, non-coal mining areas maintain a more stable moisture regime, likely due to preserved natural soil structures and processes. These contrasting findings emphasize the necessity for tailored management strategies in coal mining regions to address the unique challenges posed by altered soil characteristics and water dynamics. Full article

Oil–tea camellia has a long history of cultivation and utilization, with a history of more than 2000 years. In China, it is the main woody oil crop with high economic value and a national resource with unique characteristics. Concurrently, it is also known as one of the four major woody oil crops in the world. However, the genetic background of Camellia drupifera Lour. on Hainan Island in China is still unclear, and there is a great lack of systematic genetic characterization, which seriously hinders the development and utilization of oil–tea camellia germplasm resources and genetic improvement on Hainan Island. To analyze the genetic diversity and kinship between C. drupifera and its related species, this study utilized SSR molecular marker technology to genotype 160 individuals from 23 populations. A total of 137 alleles were amplified from the 14 polymorphic primers, with an average of 9.786. The average number of effective alleles and that of Shannon’s information index for each locus were 1.865 and 0.633, respectively, suggesting that the screened SSR markers presented a moderately high level of polymorphism. Additionally, the mean observed heterozygosity (0.915) was greater than the mean expected heterozygosity (0.450), indicating an excess of heterozygotes in the tested population. The results of the principal component analysis (PCA), molecular variation analysis of variance (AMOVA) and population structure analysis were generally consistent; specifically, there was a high degree of individual heterozygosity within the population, and genetic variation occurred primarily among individuals within the population (90%) but rarely among groups (10%). Additionally, the UPGMA clustering divided the 160 germplasm resources into four major clades, and C. drupifera was principally grouped in two distinct branches; meanwhile, Camellia gauchowensis was also mainly clustered in these two clades. Camellia oleifera individuals were chiefly concentrated in other independent branches. It can be speculated that C. drupifera is genetically close to C. gauchowensis, but genetically distant from C. oleifera. This study can provide the scientific basis for the identification, collection, preservation, evaluation, and innovative utilization of oil–tea camellia. Full article

Camellia hainanica is one of the camellia plants distributed in tropical regions, and its regeneration system and genetic transformation are affected by callus browning. However, the underlying mechanism of Camellia hainanica callus browning formation remains largely unknown. To investigate the metabolic basis and molecular mechanism of the callus browning of Camellia hainanica, histological staining, high-throughput metabolomics, and transcriptomic assays were performed on calli with different browning degrees (T1, T2, and T3). The results of histological staining revealed that the brown callus cells had obvious lignification and accumulation of polyphenols. Widely targeted metabolomics revealed 1190 differentially accumulated metabolites (DAMs), with 53 DAMs annotated as phenylpropanoids and flavonoids. Comparative transcriptomics revealed differentially expressed genes (DEGs) of the T2 vs. T1 associated with the biosynthesis and regulation of flavonoids and transcription factors in Camellia hainanica. Among them, forty-four enzyme genes associated with flavonoid biosynthesis were identified, including phenylalaninase (PAL), 4-coumaroyl CoA ligase (4CL), naringenin via flavanone 3-hydroxylase (F3H), flavonol synthase (FLS), Chalcone synthase (CHS), Chalcone isomerase (CHI), hydroxycinnamoyl-CoA shikimate transferase (HCT), Dihydroflavonol reductase (DFR), anthocyanin reductase (LAR), anthocyanin synthetase (ANS), and anthocyanin reductase (ANR). Related transcription factors R2R3-MYB, basic helix-loop-helix (bHLH), and WRKY genes also presented different expression patterns in T2 vs. T1. These results indicate that the browning of calli in Camellia hainanica is regulated at both the transcriptional and metabolic levels. The oxidation of flavonoids and the regulation of related structural genes and transcription factors are crucial decisive factors. This study preliminarily revealed the molecular mechanism of the browning of the callus of Camellia hainanensis, and the results can provide a reference for the anti-browning culture of Camellia hainanica callus. Full article

This paper investigates the effects of pre-gelation on cellulose dissolved in LiCl/DMAc solutions to enhance the properties of regenerated cellulose materials. This study focuses on characterizing the crystallinity, molecular orientation, and mechanical performance of cellulose fibers and hydrogels prepared with and without pre-gelation treatment. X-ray diffraction (XRD) analysis reveals that crystallinity improvement from 55% in untreated fibers to 59% in fibers pre-gelled for 3 and 7 days, indicating a more ordered arrangement of cellulose chains post-regeneration. Additionally, XRD patterns show improved chain alignment in pre-gelled fibers, as indicated by reduced full width at half the maximum of Azimuthal scans. Mechanical testing demonstrates a 30% increase in tensile strength and a doubling of the compression modulus for pre-gelled fibers compared to untreated fibers. These findings underscore the role of pre-gelation in optimizing cellulose material properties for applications ranging from advanced textiles to biomaterials and sustainable packaging. Future research directions include further exploration of the structural and functional benefits of pre-gelation in cellulose processing and its broader implications in material science and engineering. Full article

Between 2023 and 2024, a type of green alga was observed for the first time settling on Oil-tea Camellia leaves and branches in the eastern Oil-tea Camellia planting area of Hainan Island, forming a layer of gray-green moss with a rough surface that seriously interfered with the leaves’ normal photosynthesis. To further research the issue, this study used the plant photosynthesis measurement system and the paraffin sectioning technique to compare and analyze the changes in photosynthetic characteristics and anatomical structure of healthy and green algal-covered Oil-tea Camellia leaves. At the same time, the algal strain was effectively separated and purified using the plate delineation method, and its species classification was determined by combining morphological observation and molecular identification based on SSU-ITS sequences. The results of the study demonstrated that the coating of green alga facilitated the lignification of the leaf’s epidermal cell walls. After being covered by the green alga, the intercellular CO₂ concentration (Ci) increased significantly by 21.5%, while the net photosynthetic rate (Pn), transpiration rate (Tr), and stomatal conductance (Gs) all significantly decreased by 72.8%, 30.4%, and 24.9%, respectively. More specifically, the green alga that covers the leaves of Oil-tea Camellia was identified as Desmodesmus armatus of Chlorophyta. Notably, the green alga had a long growth cycle, did not undergo a decline phase within one month, had an optimal growth pH of 11.0, and could flourish in excessively alkaline conditions. In conclusion, this study not only reported for the first time the phenomena of D. armatus infesting Oil-tea Camellia leave, but also showed its unique physiological and ecological properties, providing a foundation for future research on relevant prevention and control approaches. Full article

Foxtail millet (Setaria italica) is an important cereal crop with rich nutritional value. Distinctness, Uniformity, and Stability (DUS) are the prerequisites for the application of new variety rights for foxtail millet. In this study, we investigated 32 DUS test characteristics of 183 foxtail millet resources, studied their artificial selection trends, and identified the varieties that conform to breeding trends. The results indicated significant differences in terms of the means, ranges, and coefficients of variation for each characteristic. A correlation analysis was performed to determine the correlations between various DUS characteristics. A principal component analysis was conducted on 31 test characteristics to determine their primary characteristics. By plotting PC1 and PC2, all the germplasm resources could be clearly distinguished. The trends in foxtail millet breeding were identified through a differential analysis of the DUS test characteristics between the landrace and cultivated varieties. Based on these breeding trends, the optimal solution types for multiple evaluation indicators were determined; the weight allocation was calculated; and a specific TOPSIS algorithm was designed to establish a comprehensive multi-criteria decision-making model. Using this model, the breeding potential of foxtail millet germplasm resources were ranked. These findings provided important reference for foxtail millet breeding in the future. Full article

The versatile electrocaloric (EC) behaviors of the (1-x)Pb(Mg_1/3Nb_2/3)O₃-xPT (PMN-100xPT) single crystal are closely related to the multiple phase transitions under the multiple fields of electric field and temperature. In this work, the EC effect of <001>-oriented PMN-30PT single crystals with chemical composition at morphotropic phase boundary has been studied during the phase transformation process from the ferroelectric rhombohedral (R) phase to the tetragonal (T) phase. Two consecutive negative EC peaks have been achieved for the first time. Based on the projection of the EC effect in the electric field-temperature phase diagram, the relationship between the EC behaviors and the phase transitions is further established. It was found that the monoclinic (M) phase actually existed during the transformation from the R phase to the T phase, and the related R-M phase transition and M-T phase transition could both induce negative EC peaks. Under the electric field of E = 10 kV/cm, the first negative EC peaks induced by the R-M phase transition is at 57 °C with ΔT_max = −0.11 K. And the M-T phase transition can produce a higher negative EC peak, and its value can reach −0.22 K at 68 °C. Based on thermodynamic calculations, the relationship between the entropy change in different phase transitions and the EC behaviors has been further elucidated. The negative EC effect originates from the structural entropy increase in the electric field-induced phase transition process. This work not only advances the research on the electrical properties of relaxor ferroelectric single crystals but also provides a new insight into high-performance ferroelectric materials design. Full article

Low power density and low heating rate are the key constraints for the development of conductive polymer materials in the field of electric heating. The carbon nanotubes (CNTs)–graphene (GR)–polydimethylsiloxane (PDMS) composite film was prepared by vacuum filtration and spin coating to solve the problem in this study. Moreover, an AC electric field was used to orient the CNTs to enhance the electrothermal performance. The structure and properties of composite films were analyzed. The results show that the composite film with CNT:GR = 2:1 has the lowest permeation threshold, and can heat up within 30 s and stabilize at 260 °C at 10 V. The electric field-oriented CNTs reduced the insulating polymer layer, increasing the heating rate of the composite film by 1.2 times, and increasing the theoretical thermal conductivity. The flexible electrothermal composite film prepared in this study can be used in thermal insulation, deicing, and wearable electronic devices. Full article

The purpose of this study was to examine the associations of social support factors with leisure-time physical activity (LTPA) of older people in Fuwen village. A cross-sectional study included 523 randomly selected elderly people (60+ years) whose LTPA levels were determined using the shortened version of the International Physical Activity Questionnaire (IPAQ-S). A modified version of the Physical Activity Social Support Scale (PASSS) was operated to gather perceived scores of the social support factors. A multivariate linear regression was performed to locate associations of perceived scores of social supports with leisure-time walking (LTW) and moderate and vigorous physical activity (MVPA). The results indicated that social support from family was positively and significantly related to LTW and MVPA in both models. The community factor was positively and significantly correlated with MVPA in both models. The sport club factor was related to LTW and MVPA to some extent. The results suggest that social support from family is the most important motivator for older people’s LTW and MVPA in the village of Fuwen. Social support from the community is the motivator for older people’s MVPA. The sport club factor has some effects on older people’s LTW and MVPA as well. More future studies are needed to extend the database of the relationship between social support and rural older people’s physical activity. Full article

A natural gas combined cooling, heating, and power (CCHP) system is a typical integrated energy supply method that optimizes end−use energy. However, how to achieve economically feasible natural gas CCHP in severe cold regions with low−grade heat demand reaching 50% is still a pressing issue. This paper establishes a typical natural gas CCHP system model for severe cold regions and conducts the system. Based on the climate conditions of Harbin, the economic optimization of independent gas turbine systems, internal combustion engines, and gas turbine systems is still a pressing issue. Based on the climate conditions of Harbin, the economic optimization of independent gas turbine systems, internal combustion engine systems, and steam boiler systems under different cooling and heating load ratios was carried out. The combination of “internal combustion engine + steam boiler” has the most optimal cost of RMB 1.766 million (USD 0.255 million), saving 10.7%, 7.8%, and 18.3% compared to the three single equipment subsystems respectively. This provides good theoretical support for the construction of multi−energy heterogeneous energy systems. Full article

Children’s footwear plays an important role in the healthy growth of foot and gait development during the growing stage. This review aims to synthesize findings of previous investigations and to explore the biomechanical influences of different types of children’s footwear on foot health and gait development, thus guiding the healthy and safe growth of children’s feet and gait. Online databases were searched for potential eligible articles, including Web of Science, Google Scholar, and PubMed. In total, nineteen articles were identified after searching based on the inclusion requirements. The following five aspects of biomechanical parameters were identified in the literature, including spatiotemporal, kinematics, kinetics, electromyography (EMG), and plantar pressure distribution. Children’s footwear can affect their foot health and gait performance. In addition, children’s shoes with different flexibility and sole hardness have different effects on children’s feet and gait development. Compared to barefoot, the stride length, step length, stride time, and step time were increased, but cadence was decreased with wearing shoes. Furthermore, the support base and toe-off time increased. Double support time and stance time increased, but single support time decreased. The hip, knee, and ankle joints showed increased range of motion in children with the rear-foot strike with larger ground reaction force as well. Future studies may need to evaluate the influence of footwear types on gait performance of children in different age groups. Findings in this study may provide recommendations for suitable footwear types for different ages, achieving the aim of growth and development in a healthy and safe manner. Full article

The deformation performance of recycled aggregate concrete can be effectively improved when basalt fiber is reasonably added. In this paper, the effects of the basalt fiber volume fraction and the length–diameter ratio on the uniaxial compression-related failure characteristics, feature points of the complete stress–strain curve and the compressive toughness of recycled concrete under different replacement rates of recycled coarse aggregate were studied. The results showed that with the increase in the fiber volume fraction, the peak stress and peak strain of basalt fiber-reinforced recycled aggregate concrete first increased and then decreased. With the increase in the fiber length–diameter ratio, the peak stress and strain of the basalt fiber-reinforced recycled aggregate concrete first increased and then decreased, whereas the effect of the length–diameter ratio on peak stress and strain of the basalt fiber-reinforced recycled aggregate concrete was clearly smaller than that of the fiber volume fraction. Based on the test results, an optimized stress–strain curve model of concrete under uniaxial compression was proposed for the basalt fiber-reinforced recycled aggregate concrete. Furthermore, it was found that the fracture energy is more suitable for evaluating the compressive toughness of the basalt fiber-reinforced recycled aggregate concrete than the tensile–compression ratio. Full article