Search Results (3,836)

The Sichuan Basin is a pivotal region for understanding the transition and evolution of Jurassic–Cretaceous dinosaur faunas in China. Despite a rich skeletal record, the quadrupedal track record from the Penglaizhen Formation remains scarce. This study reports a new sauropod tracksite discovered near Zhoujiagou in the Shuangliu District of Chengdu, Sichuan Province. The tracks occur within the upper strata of the Lower Cretaceous Penglaizhen Formation. The tracksite preserves at least three tracks constituting a possible trackway. These medium-sized impressions are characterized by a sub-circular morphology, a weak heteropody, and a potential wide-gauge trackway pattern. Based on these morphological attributes, the tracks are preliminarily referred to the Brontopodus morphotype. This discovery fills a critical gap in the sauropod ichnological record of the Penglaizhen Formation and provides evidence suggesting that mamenchisaurid dinosaurs, or their functional equivalents, persisted in the Sichuan Basin into the Early Cretaceous. Full article

Background: The pivotal role of caregivers in HIV care for older people living with HIV (PLWH) stands in stark contrast to the scarcity of research on their experiences, particularly regarding affiliate stigma. Older PLWH face a unique intersection of HIV-related stigma and ageism, which may place their family caregivers at heightened risk of affiliate stigma. However, the manifestations, sources, and coping strategies related to this stigma remain poorly understood. Methods: The descriptive phenomenological study was conducted between May and June 2025 at an HIV care clinic of a tertiary hospital in Sichuan Province, China. Using purposive sampling, fifteen caregivers of elderly individuals living with HIV were recruited. Data were collected through face-to-face, semi-structured interviews. Results: Four overarching themes and eleven sub-themes were extracted: (1) sources of affiliate stigma—‘Inadequate knowledge of HIV transmission routes’, ‘Ageism’, and ‘Infidelity stigma’; (2) experiences of affiliate stigma—‘Stigma endorsement’, ‘Concealment of a family member’s HIV-positive status’ and ‘Psychological distress’; (3) consequences of affiliate stigma—‘Estrangement among family members’, ‘Substantial caregiver burden’ and ‘Social avoidance’; and (4) coping with affiliate stigma—‘Enhancing knowledge of HIV/AIDS’ and ‘Seeking social support’. Conclusion: This study investigates affiliate stigma among caregivers of older people with HIV. Healthcare providers should recognize this stigma and its negative effects. Effective interventions must be developed to alleviate this burden, thereby improving the welfare of both caregivers and patients. Full article

Photoreceptor (PR) degeneration is a shared pathological feature of multiple blinding retinal diseases. This narrative review examines the mechanisms underlying PR vulnerability to ferroptosis-associated lipid-peroxidation injury, with emphasis on three interconnected features: the marked enrichment of docosahexaenoic acid (DHA) and other polyunsaturated fatty acids (PUFAs) in PR outer-segment disc membranes; the chronically high metabolic demand of PRs and the specialized spatial organization of their mitochondria; and retinal pigment epithelium (RPE)–PR metabolic coupling, including outer-segment renewal and phagocytic turnover, glucose transport and lactate shuttling, and visual-cycle–related all-trans-retinal (atRAL) clearance and bisretinoid accumulation. We also summarize antioxidant defense systems centered on the cystine/glutamate antiporter (xCT)–glutathione (GSH)–glutathione peroxidase 4 (GPX4) axis and mitochondrial GPX4 (mtGPX4), which restricts iron-dependent lipid peroxidation in PRs. We propose that highly oxidizable membrane phospholipid substrates, mitochondrial homeostatic imbalance, and impaired RPE–PR metabolic coupling may collectively shape PR susceptibility to ferroptosis-associated injury. From a therapeutic perspective, this framework supports multitarget strategies designed to interrupt lipid-peroxidation propagation, stabilize mitochondrial redox homeostasis and quality-control mechanisms, and restore RPE–PR metabolic support and local iron-buffering capacity. Full article

The Yangtze sturgeon (Acipenser dabryanus), a critically endangered living fossil whose wild populations are now extinct, faces new challenges to survival in captive breeding. Among these, the emergence of albino and gray color morphs raise fundamental questions about the molecular basis and physiological consequences of pigmentation loss. Here, we integrated histological, transcriptomic, and quantitative PCR to investigate pigmentation variation and associated immune alterations in this species. Histology revealed a complete absence of melanin in albino individuals and marked reduction in gray morphs. Transcriptomic profiling across the three color morphs uncovered a broad downregulation of core melanogenic genes, including PMEL, TYR, TYRP1, DCT, SLC45A2, OCA2, MREG, and MLPH, indicating impaired melanosome formation, melanin synthesis, and intracellular transport. Notably, pigmentation loss coincided with systematic changes in the expression of immune-related genes: phagosome pathway genes (e.g., C3, MHC I/II, TAP2) were downregulated, while pro-inflammatory mediators (e.g., IL-8, IL-17, CXCL10) were upregulated, suggesting a transcriptional pattern correlated with reduced expression of pathogen defense-related genes and increased genes associated with inflammation mediators. These findings reveal a mechanistic correlation between melanin deficiency and immune dysfunction in a basal vertebrate lineage, offering the first molecular evidence of an association between albinism and altered immune-related gene expression in sturgeons and highlighting its implications for conservation and captive management. Full article

The requirement for rapid and diversified performance index demonstrations for complex equipment systems conflicts with traditional fixed and singular demonstration templates. In this study, we propose a rapid demonstration model for complex equipment performance indices based on requirements to solve this limitation. We established a demonstration framework encompassing diverse requirements, schemes, and demonstration data, along with a demonstration process model based on dynamic requirements integrated through the framework. The requirement elements and index elements for demonstration are dynamically configured by characterizing the requirements and knowledge at the granularity and unit levels. Combined with a structured knowledge template, we constructed a dynamic demonstration template linking requirements and knowledge associations based on a form configuration, which constitutes a rapid configuration method for equipment performance index demonstration templates. Diverse index demonstrations for new equipment can be realized by instantiating the requirements-driven equipment performance index demonstration method. Finally, we developed a rapid demonstration tool for the error analysis of antenna arrays to verify the rationality and effectiveness of the proposed method. Full article

4-Ethylguaiacol (4-EG) is a volatile phenolic compound associated with smoky, woody, and spicy aroma notes in fermented foods and beverages, including Baijiu. In this study, a 4-EG-producing strain, designated JN11, was obtained by screening isolates from Baijiu pit mud and identified as Bacillus coagulans based on morphological, physiological, biochemical, and 16S rRNA analyses. In sorghum juice medium, strain JN11 produced 271.6 ± 2.7 μg/L 4-EG. To investigate the upstream decarboxylation step involved in volatile phenol formation, the phenolic acid decarboxylase gene, BcPAD, was cloned and heterologously expressed in Escherichia coli BL21(DE3). The BcPAD gene comprises 504 bp and encodes a 167-amino-acid protein. Recombinant BcPAD exhibited maximal activity at pH 6.0 and 50 °C and retained more than 60% residual activity after 5 h at 30–40 °C. Fe³⁺ increased enzyme activity to 115.36% of the control, whereas Zn²⁺ markedly inhibited enzyme activity and SDS completely inactivated the enzyme. BcPAD showed the highest activity toward p-coumaric acid, with a specific activity of 460.6 ± 18.3 U/mg and a catalytic efficiency (Kcat/Km) of 12.1 ± 1.4 mM⁻¹·s⁻¹, while lower activities were observed toward caffeic acid and ferulic acid, and no activity was detected toward sinapic acid. Homology modeling and molecular docking suggested that the superior catalytic performance toward p-coumaric acid may be related to favorable hydrogen-bonding interactions and substrate orientation within the active site. Although 4-EG production was observed during fermentation by strain JN11, BcPAD was biochemically characterized as a phenolic acid decarboxylase likely responsible for the upstream formation of vinyl derivatives in the proposed pathway. These findings improve our understanding of phenolic acid decarboxylases from B. coagulans and provide a basis for further investigation of the roles of strain JN11 and BcPAD in volatile phenol formation during Baijiu production. Full article

In the northern Sichuan Basin, distant from the main body of the Emeishan Large Igneous Province (ELIP), marine deposits of the Wujiaping Formation from the Permian period contain widely distributed tuffs of varying thicknesses. To clarify the genesis of these tuffs and their relationship with the ELIP, this study conducted field measurements and sample collection at the Daliang Section, Wangcang County, and the Qiaoting Section, Nanjiang County, of the northern Sichuan Basin and compared them with basalts and tuffs from Well DY1 in a minor basaltic eruption zone in the northern Sichuan Basin. The results indicate that tuffs from the Daliang and Qiaoting Sections of the northern Sichuan Basin exhibit high Al₂O₃/TiO₂ ratios (23.65–39.55) and significant depletion of Eu, Ba, and Sr elements. These characteristics suggest that their origin is linked to multiphase felsic volcanic activity within the ELIP and formation in an intraplate extensional setting. The basalts and tuffs developed at Well DY1 share the same low Al₂O₃/TiO₂ ratios (4.02–4.97), similar to the Emeishan basalts. In the Zr-Ti, Zr/Sc-Th/Sc, Nb/Y-Zr/TiO₂, and Zr/TiO₂-SiO₂ diagram plots, they fall within the basalt range, indicating that the tuffs at Well DY1 originated from the mid-ELIP eruption of basic basalt. In contrast to the felsic nature of the tuffs at Well DY1, the northern Sichuan Basin lacks records of such basic–alkaline igneous eruptions, suggesting that the influence of basalt eruptions in the northeastern Sichuan Basin is limited and does not affect the Wujiaping Formation in the northern Sichuan Basin. There is a positive correlation between volcanic activity and the total organic carbon (TOC) content of black siliceous rocks and siliceous shales in the Wujiaping Formation of northern Sichuan. The acid volcanic eruptions from Emeishan likely also played a key role in the formation of high-quality hydrocarbon source rocks in the deep-water continental shelf areas of the Wujiaping Formation in the northern Sichuan Basin. Full article

Mitochondrial dysfunction in colonic smooth muscle cells (SMCs) is closely associated with impaired gut motility in functional constipation (FC), but the underlying molecular mechanisms remain incompletely understood. The mitochondrial unfolded protein response (UPR^mt) is a critical pathway for maintaining mitochondrial proteostasis, and heat shock factor 1 (HSF1) acts as an important upstream regulator of this response. In the present study, we employed a loperamide-induced FC mouse model, combined with single-cell transcriptomic, molecular, and functional analyses to characterize the HSF1-UPR^mt pathway in colonic SMCs and to investigate its role in FC. Single-cell transcriptomic analysis of colon tissue from FC mice revealed marked downregulation of UPR^mt-associated genes in colonic SMCs. Immunofluorescence, Western blotting, and RT-qPCR analyses of colonic tissue confirmed that HSF1 expression was reduced in colonic SMCs, along with the downregulation of the UPR^mt components, including HSP60, mtHSP70, and LONP1. These molecular changes were accompanied by mitochondrial structural damage, seen by transmission electron microscopy, and by functional impairments, including reduced mitochondrial membrane potential, elevated mtROS production, decreased ATP levels, and diminished activities of respiratory chain complexes I–V. AAV9-mediated overexpression of HSF1 reactivated the UPR^mt pathway, improved mitochondrial function, and ameliorated constipation, whereas shRNA-mediated knockdown of HSF1 further suppressed UPR^mt activity and aggravated mitochondrial damage, indicating that HSF1 bidirectionally regulates this pathway. Complementary experiments in primary colonic SMCs confirmed that this regulatory mechanism operates in a cell-autonomous manner, as modulation of HSF1 expression produced corresponding changes in the UPR^mt pathway, in the expression of mitochondrial respiratory chain complex subunits (ATP5A, NDUFA9, COX1, SDHA, UQCRC1), and in ATP production, mirroring the in vivo findings. Collectively, these results demonstrate that HSF1 plays a pivotal role in maintaining mitochondrial homeostasis in colonic SMCs through regulation of the UPR^mt pathway and that HSF1 dysfunction is closely associated with slowed gut motility in FC. These findings offer a new mechanistic perspective on FC and point to the HSF1–UPR^mt axis as a potential therapeutic target. Full article

We document and illustrate Primula xideensis, a new species collected from Xide County, Sichuan Province, China. Morphologically, it resembles P. stenocalyx, P. farinosa s.l., and P. pulchella, but differs by its roots densely covered with multicellular hairs; elliptic to obovate leaves with non-revolute, irregularly and deeply dentate margins, both surfaces efarinose, shortly hairy, and scabrous; tubular calyx parted to the middle; corolla mouth densely white-farinose; stamens positioned at mid-corolla tube in pin flowers and near the throat in thrum flowers; styles reciprocally placed; and an oblong capsule shorter than the persistent calyx. To clarify its phylogenetic placement, we constructed phylogenetic trees using two datasets: 63 complete chloroplast genome sequences and 75 nuclear ribosomal DNA internal transcribed spacer (nrITS) sequences. Both trees showed similar topologies, consistently placing the new species within a monophyletic group of Sect. Aleuritia, supporting its assignment to this section. For a deeper comparison between the new species and other members of Sect. Aleuritia, we incorporated chloroplast genomes of seven additional species from this section. The results revealed highly conserved chloroplast genomes among all eight species, with only minor differences between the new species and the others. Primula xideensis is currently known only from its type locality. Based on IUCN Red List criteria, its conservation status is assessed as Data Deficient (DD). Full article

Land surface temperature (LST) is crucial for understanding winter landslide evolution. This study combines Unmanned Aerial Vehicle (UAV) photogrammetry and infrared thermography (IRT) to monitor winter landslides in China’s Wumeng Mountain region. Using the Yangjiazhai landslide—induced by underground coal mining—as a case study, we demonstrate significant correlations between IRT-detected LST anomalies and surface cracks: (1) cracks with elevated temperatures are likely connected to subsurface goaf zones; (2) excessively widened cracks show no thermal anomalies due to enhanced air convection. The research reveals that key landslide components have distinct LST signatures, governed by differential soil–rock moisture and crack networks. For accurate high-altitude winter LST acquisition, UAV thermal surveys should be conducted under overcast, fog-free conditions to reduce solar interference. This validates UAV visible–infrared fusion for extracting landslide boundaries, cracks, slumping zones, bedrock patterns, and moisture distribution. The methodology establishes a new pathway for investigating winter landslide deformation and instability, confirming IRT’s operational viability in high-altitude alpine regions. Full article

Enhancing nitrogen (N) use efficiency (NUE) is crucial for reconciling food security with fertilizer reduction and environmental protection in Sichuan province. This study used statistical data of rice, wheat, maize, and rapeseed in Sichuan Province from 2008 to 2022 to evaluate crop NUE within a regional N balance framework and compare spatiotemporal differences across the five major economic zones. Results showed that provincial NUE presented a distinct three-stage pattern: a gradual increase from 2008 to 2014, a significant surge in 2015, and a period of high-level but fluctuating NUE after 2016, the drivers of which require further investigation. By 2022, rice and rapeseed demonstrated the highest NUE values (42.89% and 42.90%, respectively), followed by maize (35.46%) and wheat (28.77%). Notable spatial heterogeneity was detected, with a general tendency of higher NUE in the southeastern and basin areas and lower NUE in the northwestern mountainous areas. Northeastern Sichuan, Southern Sichuan and the Chengdu Plain consistently exhibited better performance, while Northwest Sichuan remained the region with the weakest performance. These findings suggest that improving NUE in Sichuan province necessitates region- and crop-specific strategies, with priority being given to stabilizing the high NUE of rice and rapeseed, while targeting infrastructure improvement and precision fertilizer management in wheat-dominated and low-efficiency areas. Full article

The environmental impacts of treated acid mine drainage on receiving river systems remain insufficiently understood. This study investigated four typical closed coal mines in northern Sichuan Province, China, by analyzing heavy metals, sulfate, pH, UV-Vis spectroscopy, and dissolved organic matter (DOM) characteristics at 24 sampling sites along the receiving reaches. Parallel factor analysis (PARAFAC) and two-dimensional correlation spectroscopy (2D-COS) were employed to examine the longitudinal response sequence of DOM components. Results showed that pollutant concentrations generally increased immediately after the inflow of treated acid mine drainage and then progressively attenuated downstream, although the dominant pollution factors varied significantly among the reaches. DOM composition exhibited spatial heterogeneity, with protein-like components dominating three reaches and humic-like components prevailing in one reach. Based on the co-variation characteristics of DOM and heavy metals along the river course, four response patterns were identified: rapid-recovery, slow-recovery, disturbance–oscillation recovery, and delayed-recovery patterns. The 2D-COS analysis validated the rationality of these four patterns and revealed differences in the sensitivity of various DOM components to longitudinal disturbances. This study provides a scientific basis for the environmental impact assessment of mine water from remediated closed coal mines. Full article

The spatial distribution of flammable tree species directly influences forest fuel structure and fire risk patterns. However, mixed pixels limit the ability of conventional classification methods to characterize continuous within-pixel variation in species composition, thereby constraining fine-scale forest mapping. To address this issue, this study developed a subpixel mapping framework for flammable tree species in Yajiang County, Sichuan Province, by integrating Sentinel-2 time-series data with a spectral mixing–unmixing strategy. Using 2019 Sentinel-2 time-series data and National Forest Inventory (NFI) data, temporal mixed samples with known abundance fractions were generated using a linear spectral mixing model. An XGBoost-based collaborative multi-regression framework was then applied to estimate the proportions of different tree-species endmembers within complex forest pixels. Quantitative evaluation using synthetic mixed samples showed that the model achieved stable unmixing performance across different random mixing scenarios. The best performance was obtained under the Mixed 2 scenario with a sample size of 250 K, reaching an R² of 0.821. The resulting maps revealed continuous spatial variation in the abundance and composition of flammable tree species. Mountain pine was the most widespread and dominant species, followed by spruce and mountain oak, whereas birch and fir mainly exhibited localized patchy distributions. An additional NFI-based categorical evaluation assessed the consistency of the final maps with real forest inventory records. The identification accuracies were 93.95% for pure stands and 91.22% for mixed stands, while the species classification accuracies were 87.28% for pure stands and 84.41% for dominant species in mixed stands. The proposed framework provides useful spatial information for regional forest fuel assessment and fire risk management. Full article

Sulfate attack is a major cause of deterioration in tunnel lining concrete under aggressive underground conditions. This study investigates the sulfate resistance of fiber-reinforced ferroaluminate cement concrete incorporating steel slag powder through combined experimental and numerical approaches. Specimens with different fiber contents (0, 0.2%, and 0.4%) were subjected to dry–wet cycles in a 5% sodium sulfate solution. The results show that fiber incorporation significantly enhances sulfate resistance, with the optimal performance achieved at 0.2% fiber content. Compared with ordinary Portland cement concrete, ferroaluminate cement-based concrete exhibits improved durability, including lower mass variation, reduced strength degradation, and more stable dynamic elastic modulus. Microstructural analyses indicate that hydration products refine the pore structure, while fibers effectively inhibit crack propagation and expansion damage. Numerical simulation of tunnel lining structures further demonstrates that the optimized material reduces stress concentration, displacement, and crack development. Overall, the proposed material shows superior performance and promising application potential for tunnel linings in sulfate-rich environments. Full article

Radiation-induced intestinal injury (RIII) is a common complication of tumor radiotherapy, significantly impacting patients’ quality of life and posing challenges for developing effective medical countermeasures. This study investigated the reparative effects of the traditional Chinese medicine Pyrrosia petiolosa (Christ) Ching on radiation damage through in vivo and in vitro models. By integrating gut microbiota and untargeted metabolomics analyses, it elucidated the multidimensional mechanisms through which P. petiolosa regulates the microbiome as well as metabolic homeostasis. In vitro experiments demonstrated that P. petiolosa effectively suppressed radiation-induced inflammatory factors (IL-6, TNF-α, and IL-1β) and alleviated radiation-induced oxidative stress (MDA, GSH, and SOD). In vivo models further confirmed that P. petiolosa significantly alleviated radiation-induced intestinal inflammation and leukopenia, while protecting the structural and functional integrity of mouse small intestinal crypt villi. Mechanistic studies revealed P. petiolosa reshaped the gut microbiota by promoting enrichment of beneficial bacteria such as Bacteroides, concurrently restoring the homeostasis of key metabolic pathways, including glutathione, glycerophospholipids, and the tricarboxylic acid cycle. Analysis of the microbiome–metabolome interaction network revealed that treatment with P. petiolosa altered the correlation patterns between gut microbiota and fecal metabolites, including potentially beneficial bacteria and metabolites associated with inflammatory and oxidative stress responses. These findings suggest that microbiome–metabolome remodeling may contribute to the protective effects of P. petiolosa against radiation-induced intestinal damage. Overall, this study provides preliminary evidence that P. petiolosa may alleviate acute radiation-induced intestinal damage through anti-inflammatory and antioxidant effects accompanied by changes in gut microbiota and metabolic homeostasis, while identifying candidate targets for future functional validation. Full article