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Methamphetamine (METH) has been implicated in inducing memory impairment, but the precise mechanisms underlying this effect remain unclear. Current research often limits itself to singular models or focuses on individual gene or protein functions, which hampers a comprehensive understanding of the underlying mechanisms. In this study, we established three METH mouse exposure models, extracted hippocampal nuclei, and utilized RNA sequencing to analyze changes in mRNA expression profiles. Our results indicate that METH significantly impairs the learning and memory capabilities of mice. Additionally, we observed that METH-induced inflammatory responses occur in the early phase and do not further exacerbate with repeated injections. However, RNA sequencing revealed the persistent enrichment of inflammatory pathway molecules, which correlated with worsened behaviors. This suggests that although METH-induced neuroinflammation plays a critical role in learning and memory impairment, the continued enrichment of inflammatory pathway molecules is associated with behavioral outcomes. These findings provide crucial evidence for the potential application of immune intervention in METH-related disorders.

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Currently, the global prevalence of myopia is high and on the rise, seriously affecting the health of students. Studies have suggested that dietary factors may be associated with the occurrence and development of myopia, but the results are inconsistent. This survey aims to analyze the correlation between dietary factors and myopia while controlling for more confounding factors. A multi-stage stratified cluster sampling method was performed to select 10,619 primary and secondary school students in Shenyang for visual examination, and questionnaires were administered to 6974 of them. Logistic regression was performed with myopia as the dependent variable and the variables with p < 0.1 in the univariate analysis as independent variables. Sensitivity analysis was conducted using propensity score matching. The results showed that the overall prevalence of myopia among primary and secondary school students in Shenyang was 59.1%, with mild myopia predominating. Students who ate fresh fruits two or more times a day had a 0.69 times lower risk of myopia compared to those who did not eat fruits (95% CI 0.50-0.97). However, subgroup analysis demonstrated that this protective effect was only significant for male students, with an OR of 0.59 (95% CI 0.38-0.91). Moreover, female students who consumed sugary beverages once or more a day had a 1.8 times higher risk of myopia compared to those who did not consume sugary beverages (95% CI 1.03-3.15). Vegetable consumption, intake of fried foods, and breakfast habits were not significantly associated with myopia. In summary, excessive consumption of sugary beverages could increase the risk of myopia, especially in female students, whereas fruit intake contributed to reducing the risk of myopia, particularly in male students.

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High levels of antibiotic accumulation and the difficulty of degradation can have serious consequences for the environment and, therefore, require urgent attention. To solve this problem, a synergistic Er and Cd ion-codoped Bi4O5Br2 photocatalyst was proposed. The degradation rate of sulfamethoxazole (SMX) by Er/Cd-Bi4O5Br2 was eight times higher than that of pure Bi4O5Br2, exceeding that of single Er-doped or Cd-doped Bi4O5Br2, which was attributed to the ability of Er/Cd-Bi4O5Br2 to generate a variety of free radicals. Experimental results and theoretical calculations suggested a possible mechanism for the improved photocatalytic degradation rate. The reduction of the band gap can facilitate the production of electron-hole pairs, which play a significant role in the production of reactive radicals. Furthermore, an optimal stabilized structure of the ErCd-Bi4O5Br2 dopant system was identified based on the formation energy formulas of different ligand configurations. These findings offer promising potential for the degradation of broad-spectrum antibiotics and provide valuable insights for the design and modification of photocatalytic materials.

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Atherosclerosis, a major cause of cardiovascular diseases, is characterized by the accumulation of oxidized lipoproteins (ox-LDL) within arterial walls, leading to inflammation and plaque formation. Hydrogen sulfide (H2S) has demonstrated anti-inflammatory and vascular protective properties, but its role in modulating macrophage endocytosis of ox-LDL and its impact on early atherosclerosis development remains unclear. Macrophage cultures were utilized for ox-LDL uptake experiments. Macrophages were pretreated with sodium hydrosulfide (NaHS) (50 µmol/L) or propargylglycine (PPG, 3 mmol/L) for 1 h, followed by incubation with DiI-ox-LDL (10 µg/mL) for an additional 2 h. DiI-ox-LDL uptake was visualized using live-cell imaging. The expression of scavenger receptors CD36 and SR-A was assessed through immunofluorescent staining and western blot analysis. To determine the intracellular signal transduction pathways involved, macrophages were pretreated with NF-κB pathway blocker pyrrolidine dithiocarbamate or MAPK inhibitor PD98059 before the addition of NaHS. NaHS significantly inhibited ox-LDL uptake by macrophages, while PPG treatment markedly increased this process. Immunocytochemistry and western blot analysis revealed that the expressions of CD36 and SR-A were induced by ox-LDL but inhibited by NaHS in a concentration- and time-dependent manner. Furthermore, H2S down-regulated ox-LDL receptors CD36 and SR-A through the NF-κB signal pathway. H2S inhibits early atherosclerosis development by modulating macrophage uptake of ox-LDL through the down-regulation of CD36 and SR-A receptors via the NF-κB signaling pathway. These findings provide new evidence for the role of H2S in atherosclerosis and its potential therapeutic value.

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Endocytosis is a fundamental biological process that couples exocytosis to maintain the homeostasis of the plasma membrane and sustained neurotransmission. Super-resolution microscopy enables optical imaging of exocytosis and endocytosis in live cells and makes an essential contribution to understanding molecular mechanisms of endocytosis in neuronal somata and other types of cells. However, visualization of exo-endocytic events at the single vesicular level in a synapse with optical imaging remains a great challenge to reveal mechanisms governing the synaptic exo-endocytotic coupling. In this protocol, we describe the technical details of stimulated emission depletion (STED) imaging of synaptic endocytosis at the single-vesicle level, from sample preparation and microscopy calibration to data acquisition and analysis.

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There is a need to develop simple and effective strategies for the rapid detection of heavy metal ions (HMIs) in order to protect the environment and human health. A simple fluorescent sensor array based on a single cucurbit[5]uril-truxene probe was proposed to simultaneously identify five HMIs (Pb2+, Cu2+, Ag+, Fe2+ and Fe3+). This probe was synthesized using monohydroxyl cucurbit[5]uril and monobromohexyl truxene by a substitution reaction between them. It could be observed that the fluorescence response of this synthesized probe to HMIs was closely related to the pH of the aqueous solution, exhibiting different fluorescence intensities at pH 3.0, 7.0, and 9.0. Based on this phenomenon, a fluorescent sensor array based on a single cucurbit[5]uril-truxene probe was then constructed by simply altering the pH in the sensor element. These unique fluorescence responses were analyzed using linear discriminant analysis (LDA) to identify metal ions. A concentration limit classification of 0.1 µM was applied to the above five HMIs. Moreover, the quantification of metal ions was implemented even at low concentrations of 48-121 nM. This array showed good results in the recognition of metal ions in real water samples (lake water and tap water samples), which shows its broad application prospects in many fields, including monitoring of the environmental water quality and so on.

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Grain boundary (GB) precipitation-induced cracking is a significant issue for S31254 super austenitic stainless steel during hot working. Investigating the deformation behavior based on precipitate morphology and distribution is essential. In this study, continuous smaller and intermittent larger precipitates were obtained through heat treatments at 950 °C and 1050 °C. The microstructure evolution and mechanical properties influenced by precipitates were experimentally investigated using an in situ tensile stage inside a scanning electron microscope (SEM) combined with electron backscatter diffraction (EBSD). The results showed that continuous precipitates at 950 °C had a stronger pinning effect on the GB, making grain rotation difficult and promoting slip deformation in the plastic interval. Continuous precipitates caused severe stress concentration near GB and reduced coordinated deformation ability. Additionally, the crack propagation path changed from transcrystalline to intercrystalline. Furthermore, internal precipitates were a crucial factor affecting the initial crack nucleation position. Interconnected precipitates led to an intergranular fracture tendency and severe deterioration of the material's plasticity, as observed in fracture morphology.

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Yang-deficiency constitution (YADC) is linked to a higher vulnerability to various diseases, such as cold coagulation and blood stasis (CCBS) syndrome and infertility. Endometrial hyperplastic processes (EHPs) are a leading cause of infertility in women and are characterized by CCBS. However, it remains unclear whether YADC is related to the development of EHPs. METHODS: We recruited 202 EHPs patients including 147 with YADC (YEH group) and 55 with non-YADC (NYEH group). Fecal samples were collected from 8 YEH patients and 3 NYEH patients and analyzed using 16S rRNA V3-V4 sequencing for gut microbiota analysis. We obtained constitution survey data and a differential gut microbiota dataset from the literature for further analysis. Bioinformatics analysis was conducted using gut microbiota-related genes from public databases. RESULTS: YADC was significantly more prevalent in EHPs than non-YADC (P < 0.001), suggesting it as a potential risk factor for EHPs occurrence (ORpopulation survey = 13.471; ORhealthy women = 5.173). The YEH group had higher levels of inflammation, estrogen, and tamoxifen-related flora compared to NYEH and healthy YADC groups. There was an interaction between inflammation, estrogen, differential flora, and EHPs-related genes, particularly the TNF gene (related to inflammation) and the EGFR gene (related to estrogen), which may play a crucial role in EHPs development. CONCLUSION: YEH individuals exhibit significant changes in their gut microbiota compared to NYEH and healthy YADC. The interaction between specific microbiota and host genes is believed to play a critical role in the progression of EHPs.

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Introduction: The uridine diphosphate (UDP)-glycosyltransferase (UGT) family is the largest glycosyltransferase family, which is involved in the biosynthesis of natural plant products and response to abiotic stress. UGT has been studied in many medicinal plants, but there are few reports on Platycodon grandiflorus. This study is devoted to genome-wide analysis of UGT family and identification of UGT genes involved in drought stress of Platycodon grandiflorus (PgUGTs). Methods: The genome data of Platycodon grandiflorus was used for genome-wide identification of PgUGTs, online website and bioinformatics analysis software was used to conduct bioinformatics analysis of PgUGT genes and the genes highly responsive to drought stress were screened out by qRT-PCR, these genes were cloned and conducted bioinformatics analysis. Results: A total of 75 PgUGT genes were identified in P.grandiflorus genome and clustered into 14 subgroups. The PgUGTs were distributed on nine chromosomes, containing multiple cis-acting elements and 22 pairs of duplicate genes were identified. Protein-protein interaction analysis was performed to predict the interaction between PgUGT proteins. Additionally, six genes were upregulated after 3d under drought stress and three genes (PGrchr09G0563, PGrchr06G0523, PGrchr06G1266) responded significantly to drought stress, as confirmed by qRT-PCR. This was especially true for PGrchr06G1266, the expression of which increased 16.21-fold after 3d of treatment. We cloned and conducted bioinformatics analysis of three candidate genes, both of which contained conserved motifs and several cis-acting elements related to stress response, PGrchr06G1266 contained the most elements. Discussion: PgGT1 was confirmed to catalyze the C-3 position of platycodin D and only eight amino acids showed differences between gene PGr008G1527 and PgGT1, which means PGr008G1527 may be able to catalyze the C-3 position of platycodin D in the same manner as PgGT1. Seven genes were highly expressed in the roots, stems, and leaves, these genes may play important roles in the development of the roots, stems, and leaves of P. grandiflorus. Three genes were highly responsive to drought stress, among which the expression of PGrchr06G1266 was increased 16.21-fold after 3d of drought stress treatment, indicating that PGrchr06G1266 plays an important role in drought stress tolerance. To summarize, this study laied the foundation to better understand the molecular bases of responses to drought stress and the biosynthesis of platycodin.

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INTRODUCTION: A growing number of randomized controlled trials (RCTs) have demonstrated the effectiveness of tumor necrosis factor-α (TNF-α) inhibitors in treating non-radiographic axial spondyloarthritis (nr-axSpA). This study aimed to evaluate the efficacy of TNF-α inhibitors in the treatment of nr-axSpA. METHODS: PubMed, EMBASE, Web of Science, and the Cochrane Library databases were systematically searched for relevant RCTs using specific keywords up to June 2023. The primary outcome was the proportion of patients who achieved Assessment in SpondyloArthritis international Society 40% (ASAS40). Secondary outcomes included ASAS20, Bath Ankylosing Spondylitis Disease Activity Index 50% (BASDAI50), ASAS partial remission, and ASAS5/6. RESULTS: A total of eight RCTs involving 1,376 patients were included. Patients receiving anti-TNF therapy exhibited a higher rate of ASAS40 (pooled RR = 2.36; 95% CI: 1.63-3.42; p < 0.001). In addition, the TNF-α inhibitor group showed higher BASDAI50 rates (pooled RR = 2.06; 95% CI: 1.48-2.89), ASAS20 rates (pooled RR = 1.48; 95% CI: 1.31-1.67), ASAS partial remission rates (pooled RR = 2.33; 95% CI: 1.58-3.43), and ASAS5/6 rates (RR = 3.46; 95% CI: 2.05-5.83) than the placebo group. CONCLUSION: The TNF-α inhibitors were effective in treating nr-axSpA.

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BACKGROUND: Identification of the causes of stroke of undetermined etiology, specifically cardioembolism (CE) and non-CE causes, can inform treatment planning and prognosis prediction. The objective of this study was to analyze the disparities in thrombus composition, particularly Semaphorin-7A (Sema7A) and CD163, between patients diagnosed with large-artery atherosclerosis (LAA) and those with CE, and to investigate their potential association with prognosis. METHODS: Thrombi were collected from patients who underwent mechanical thrombectomy at two hospitals. The patients were categorized into two groups: LAA and CE. We compared the levels of Sema7A and CD163 between these groups and analyzed their relationships with stroke severity, hemorrhagic transformation and prognosis. RESULTS: The study involved a total of 67 patients. Sema7A expression was found to be significantly higher in the CE group compared to LAA (p < 0.001). Conversely, no statistically significant differences were observed for CD163 between the groups. The presence of Sema7A/CD163 did not show any associations with stroke severity or hemorrhagic transformation (all p > 0.05). However, both Sema7A (OR, 2.017; 95% CI, 1.301-3.518; p = 0.005) and CD163 (OR, 2.283; 95% CI, 1.252-5.724; p = 0.03) were associated with the poor prognosis for stroke, after adjusting for stroke severity. CONCLUSION: This study highlights that CE thrombi exhibited higher levels of Sema7A expression compared to LAA thrombi. Moreover, we found a positive correlation between Sema7A/CD163 levels and the poor prognosis of patients with acute ischemic stroke.

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Background: The infiltration and activation of immune cells in the tumor microenvironment (TIME) affect the prognosis of patients with cancer. Tertiary lymphoid structure (TLS) formation favors tumour- infiltrating-lymphocyte (TIL) recruitment and is regarded as an important indicator of good prognosis associated with immunotherapy in patients with tumors. Chemotherapy is currently one of the most commonly used clinical treatment methods. However, there have been no clear report to explore the effects of different types of chemotherapy on TLS formation in the TIME. This study examined the effects of immunogenic cell death (ICD)-inducing chemotherapeutics on immune cells, high-endothelial venules (HEV), and TLSs in mouse melanomas. Methods: Doxorubicin (an ICD inducer), gemcitabine (non-ICD inducer), and a combination of the two drugs was delivered intra-peritoneally to B16F1-loaded C57BL/6 mice. The infiltration of immune cells into tumor tissues was evaluated using flow cytometry. HEV and TLS formation was assessed using immunohistochemistry and multiple fluorescent immunohistochemical staining. Results: Doxorubicin alone, gemcitabine alone, and the two-drug combination all slowed tumor growth, with the combined treatment demonstrating a more pronounced effect. Compared with the control group, the doxorubicin group showed a higher infiltration of CD8+ T cells and tissue-resident memory T cells (TRM) and an increase in the secretion of interferon-γ, granzyme B, and perforin in CD8+ T subsets and activation of B cells and dendritic cells. Doxorubicin alone and in combination with gemcitabine decreased regulatory T cells in the TIME. Moreover, doxorubicin treatment promoted the formation of HEV and TLS. Doxorubicin treatment also upregulated the expression of programmed cell death protein (PD)-1 in CD8+ T cells and programmed cell death protein ligand (PD-L)1 in tumor cells. Conclusions: These results indicate that doxorubicin with an ICD reaction promotes TLS formation and increases PD-1/PD-L1 expression in tumor tissues. The results demonstrate the development of a therapeutic avenue using combined immune checkpoint therapy.

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The central mechanisms underlying pain chronicity remain elusive. Here, we identify a reciprocal neuronal circuit in mice between the anterior cingulate cortex (ACC) and the ventral tegmental area (VTA) that mediates mutual exacerbation between hyperalgesia and allodynia and their emotional consequences and, thereby, the chronicity of neuropathic pain. ACC glutamatergic neurons (ACCGlu) projecting to the VTA indirectly inhibit dopaminergic neurons (VTADA) by activating local GABAergic interneurons (VTAGABA), and this effect is reinforced after nerve injury. VTADA neurons in turn project to the ACC and synapse to the initial ACCGlu neurons to convey feedback information from emotional changes. Thus, an ACCGlu-VTAGABA-VTADA-ACCGlu positive-feedback loop mediates the progression to and maintenance of persistent pain and comorbid anxiodepressive-like behavior. Disruption of this feedback loop relieves hyperalgesia and anxiodepressive-like behavior in a mouse model of neuropathic pain, both acutely and in the long term.

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BACKGROUND: Exendin-4 (Ex4) is a promising drug for diabetes mellitus with a half-life of 2.4 h in human bodies. Besides, the Ex4 formulations currently employed in the clinic or under development have problems pertaining to stability. In this study, palmitic acid-modified Ex4 (Pal-Ex4) was prepared and purified to extend the half-life of Ex4. In addition, Pal-Ex4-MVLs were further designed and optimized as a long-acting delivery system for intramuscular injection. METHODS: Pal-Ex4 was encapsulated within multivesicular liposomes (MVLs) via a two-step double emulsification process. The formulated products were then assessed for their vesicle size, encapsulation efficiency, and in vitro and in vivo. RESULTS: Pal-Ex4-MVLs with a notable encapsulation efficiency of 99.18% were successfully prepared. Pal-Ex4-MVLs, administered via a single intramuscular injection in Sprague-Dawley rats, sustained stable plasma concentrations for 168 h, presenting extended half-life (77.28 ± 12.919 h) and enhanced relative bioavailability (664.18%). MVLs protected Ex4 through providing stable retention and slow release. This approach considerably improved the in-situ stability of the drug for intramuscular administration. CONCLUSIONS: The combination of palmitic acid modification process with MVLs provides dual protection for Ex4 and can be a promising strategy for other hydrophilic protein/polypeptide-loaded sustained-release delivery systems with high drug bioactivity.

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The WRKY family of transcription factors (TFs) is an important gene family involved in abiotic stress responses. Although the roles of WRKY TFs in plant abiotic stress responses are well studied, little is known about the stress-induced changes in WRKY family in Platycodon grandiflorus. 42 PgWRKY genes in seven subgroups were identified in the P. grandiflorus genome. The content of eight platycodins in P. grandiflorus was investigated under cold, heat, and drought stresses. Platycodin D levels significantly increased under three abiotic stresses, while the content changes of other platycodins varied. Transcriptome analysis showed that different WRKY family members exhibited varied expression patterns under different abiotic stresses. PgWRKY20, PgWRKY26, and PgWRKY39 were identified as three key candidates for temperature and drought stress responses, and were cloned and analysed for sequence characteristics, gene structure, subcellular localisation, and expression patterns. The RT-qPCR results showed that PgWRKY26 expression significantly increased after heat stress for 48 h, cold stress for 6 h, and drought stress for 2 d (DS_2 d). The PgWRKY39 expression level significantly increased at DS_2 d. This study provides a theoretical basis for clarifying the molecular mechanism of the abiotic stress responses of the WRKY gene family in P. grandiflorus.

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We utilized a first-principle density functional theory for a comprehensive analysis of CsPbX3 (X = F, Cl, Br, I) to explore its physical and chemical properties, including its mechanical behavior, electronic structure and optical properties. Calculations show that all four materials have good stability, modulus of elasticity, hardness and wear resistance. Additionally, CsPbX3 demonstrates a vertical electron leap and serves as a semiconductor material with direct band gaps of 3.600 eV, 3.111 eV, 2.538 eV and 2.085 eV. In examining its optical properties, we observed that the real and imaginary components of the dielectric function exhibit peaks within the low-energy range. Furthermore, the dielectric function gradually decreases as the photon energy increases. The absorption spectrum reveals that the CsPbX3 material exhibits the highest UV light absorption, and as X changes (with the increase in atomic radius within the halogen group of elements), the light absorption undergoes a red shift, becoming stronger and enhancing light utilization. These properties underscore the material's potential for application in microelectronic and optoelectronic device production. Moreover, they provide a theoretical reference for future investigations into CsPbX3 materials.

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MAIN CONCLUSION: Two trans-isopentenyl diphosphate synthase and one squalene synthase genes were identified and proved to be involved in the triterpenoid biosynthesis in Platycodon grandiflorus. Platycodon grandiflorus is a commonly used traditional Chinese medicine. The main bioactive compounds of P. grandiflorus are triterpenoid saponins. The biosynthetic pathway of triterpenoid saponins in P. grandiflorus has been preliminarily explored. However, limited functional information on related genes has been reported. A total of three trans-isopentenyl diphosphate synthases (trans-IDSs) genes (PgFPPS, PgGGPPS1 and PgGGPPS2) and one squalene synthase (SQS) gene (PgSQS) in P. grandiflorus were screened and identified from transcriptome dataset. Subcellular localization of the proteins was defined based on the analysis of GFP-tagged. The activity of genes was verified in Escherichia coli, demonstrating that recombinant PgFPPS catalysed the production of farnesyl diphosphate. PgGGPPS1 produced geranylgeranyl diphosphate, whereas PgGGPPS2 did not exhibit catalytic activity. By structural identification of encoding genes, a transmembrane region was found at the C-terminus of the PgSQS gene, which produced an insoluble protein when expressed in E. coli but showed no apparent effect on the enzyme function. Furthermore, some triterpenoid saponin synthesis-related genes were discovered by combining the component content and the gene expression assays at the five growth stages of P. grandiflorus seedlings. The accumulation of active components in P. grandiflorus was closely associated with the expression level of genes related to the synthesis pathway.

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There is growing evidence that the prevalence of high blood pressure is increasing, and it may have serious consequences. However, research on the prevalence and influencing factors of high blood pressure among primary and secondary school students is still relatively scarce. This study aims to investigate the prevalence and influencing factors of high blood pressure among primary and secondary school students in Shenyang, in order to provide scientific evidence for the prevention and management of this disease. From April to May 2020, 4892 students aged 7 to 17 years were selected as the survey subjects, and on-site physical measurements and questionnaire surveys were conducted. The prevalence of high blood pressure was described. Restricted cubic spline was used to analyze the dose-response relationship between sleep duration, BMI and the risk of high blood pressure. Logistic regression was used to analyze the risk factors. Multiplicative and additive models were used to analyze the interaction between sleep duration and BMI. The results showed that the overall prevalence of high blood pressure among students aged 7 to 17 years in Shenyang was 9.9%, with a higher prevalence in females than males (12.1% vs 7.9%) and in urban areas than suburban areas (11.8% vs 7.7%). The prevalence was lowest in students with normal weight (8.3%) and highest in those who were obese (12.5%). The prevalence fluctuated to some extent among different age groups, but overall, it increased with age, with the lowest prevalence in primary school students (7.0%), 11.4% in mild school students, and the highest prevalence of 14.3% in high school students. Multivariable analysis showed that the risk of high blood pressure in female students was 1.90 times higher than that in male students (95% CI: 1.54-2.35), and the risk in suburban areas was 0.65 times lower than that in urban areas (95% CI: 0.52-0.81). Students with a BMI ≥ 21 kg/m2 had a 1.58 times higher risk than those with a BMI < 21 kg/m2(95% CI: 1.28-1.96), while those with a sleep time ≥ 8 hours had a 0.80 times lower risk than those with a sleep time < 8 hours (95% CI: 0.65-0.99). Exercise can significantly reduce the risk of high blood pressure, while using electronic devices for more than 0.5 hours significantly increases the risk of high blood pressure. BMI and sleep duration have no interaction effect on the risk of high blood pressure. To reduce the prevalence of high blood pressure, students should reduce the use of electronic devices, ensure adequate exercise, maintain a reasonable weight, and ensure sufficient sleep.

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The acid-induced gelation of pectin in potato cell walls has been gradually recognized to be related to the improvement in the cell wall integrity after heat processing. The aim of this study was to characterize the acid-induced gelation of original pectin from a potato cell wall (OPP). Rheological analyses showed a typical solution-sol-gel transition process of OPP with different additions of gluconic acid-δ-lactone (GDL). The gelation time (Gt) of OPP was significantly shortened from 7424 s to 2286 s. The complex viscosity (η*) of OPP gradually increased after 4000 s when the pH was lower than 3.13 and increased from 0.15 to a range of 0.20~6.3 Pa·s at 9000 s. The increase in shear rate caused a decrease in η, indicating that OPP belongs to a typical non-Newtonian fluid. Furthermore, a decrease in ζ-potential (from -21.5 mV to -11.3 mV) and an increase in particle size distribution (from a nano to micro scale) was observed in OPP after gelation, as well as a more complex (fractal dimension increased from 1.78 to 1.86) and compact (cores observed by cryo-SEM became smaller and denser) structure. The crystallinity of OPP also increased from 8.61% to 26.44%~38.11% with the addition of GDL. The above results call for an investigation of the role of acid-induced OPP gelation on potato cell walls after heat processing.

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To understand carbon sequestration capacity of grasslands, the changes of CO2 flux in Xilinhot grasslands and the influence of environmental factors were analyzed by using the eddy data of Xilinhot National Climate Observatory in 2018-2021, and the distribution of flux source areas was analyzed. The results showed that the southwest wind prevailed in the study area throughout the year, the source area in the growing season was larger than that in the non-growing season, and the source area under stable atmospheric conditions was larger than that under unstable conditions. The maximum length of source region with a contribution rate of 90% was close to 400 m, which was consistent with the length estimated by the classical law. The net ecosystem exchange (NEE) of Xilinhot grasslands had obvious diurnal and seasonal dynamics, which was manifested as a carbon sink in the daytime and a carbon source at night during the growing season and weak carbon source in the non-growing season. From 2018 to 2021, the annual total NEE were -15.59, -46.28, -41.94, and -78.14 g C·m-2·a-1, respectively, with an average value of -45.49 g C·m-2·a-1, indicating that Xilinhot grassland had strong carbon sequestration capacity. Vapor pressure deficit and photosynthetically active radiation helped grasslands absorb atmospheric CO2. At night, when temperature was above 0 ℃, the increases in air and soil temperature promoted vegetation respiration to release CO2.

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