Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 583
Filtrar
Más filtros

Tipo del documento
Intervalo de año de publicación
1.
Proc Natl Acad Sci U S A ; 120(32): e2302190120, 2023 08 08.
Artículo en Inglés | MEDLINE | ID: mdl-37523548

RESUMEN

The paucity of investigations of carbon (C) dynamics through the soil profile with warming makes it challenging to evaluate the terrestrial C feedback to climate change. Soil microbes are important engines driving terrestrial biogeochemical cycles; their carbon use efficiency (CUE), defined as the proportion of metabolized organic C allocated to microbial biomass, is a key regulator controlling the fate of soil C. It has been theorized that microbial CUE should decline with warming; however, empirical evidence for this response is scarce, and data from deeper soils are particularly scarce. Here, based on soil samples from a whole-soil-profile warming experiment (0 to 1 m, +4 °C) and 18O tracing approach, we examined the vertical variation of microbial CUE and its response to ~3.3-y experimental warming in an alpine grassland on the Qinghai-Tibetan Plateau. Microbial CUE decreased with soil depth, a trend that was primarily controlled by soil C availability. However, warming had limited effects on microbial CUE regardless of soil depth. Similarly, warming had no significant effect on soil C availability, as characterized by extractable organic C, enzyme-based lignocellulose index, and lignin phenol-based ratios of vanillyls, syringyls, and cinnamyls. Collectively, our work suggests that short-term warming does not alter microbial CUE in either surface or deep soils, and emphasizes the regulatory role of soil C availability on microbial CUE.


Asunto(s)
Pradera , Suelo , Suelo/química , Carbono/metabolismo , Microbiología del Suelo , Cambio Climático
2.
J Immunol ; 210(9): 1408-1418, 2023 05 01.
Artículo en Inglés | MEDLINE | ID: mdl-36971659

RESUMEN

Complement receptor type 2 (CR2) is an important membrane molecule expressed on B cells and follicular dendritic cells. Human CR2 has been shown to play a critical role in bridging the innate complement-mediated immune response with adaptive immunity by binding complement component 3d (C3d). However, the chicken CR2 (chCR2) gene has not been identified or characterized. In this study, unannotated genes that contain short consensus repeat (SCR) domains were analyzed based on RNA sequencing data for chicken bursa lymphocytes, and a gene with >80% homology to CR2 from other bird species was obtained. The gene consisted of 370 aa and was much smaller than the human CR2 gene because 10-11 SCRs were missing. The gene was then demonstrated as a chCR2 that exhibited high binding activity to chicken C3d. Further studies revealed that chCR2 interacts with chicken C3d through a binding site in its SCR1-4 region. An anti-chCR2 mAb that recognizes the epitope 258CKEISCVFPEVQ269 was prepared. Based on the anti-chCR2 mAb, the flow cytometry and confocal laser scanning microscopy experiments confirmed that chCR2 was expressed on the surface of bursal B lymphocytes and DT40 cells. Immunohistochemistry and quantitative PCR analyses further indicated that chCR2 is predominantly expressed in the spleen, bursa, and thymus, as well as in PBLs. Additionally, the expression of chCR2 varied according to the infectious bursal disease virus infection status. Collectively, this study identified and characterized chCR2 as a distinct immunological marker in chicken B cells.


Asunto(s)
Pollos , Complemento C3d , Animales , Humanos , Complemento C3d/metabolismo , Receptores de Complemento 3d/metabolismo , Sitios de Unión , Factores Inmunológicos , Receptores de Complemento
3.
Mol Ther ; 32(3): 749-765, 2024 Mar 06.
Artículo en Inglés | MEDLINE | ID: mdl-38310356

RESUMEN

Approximately 80%-90% of hepatocellular carcinomas (HCC) occur in a premalignant environment of fibrosis and abnormal extracellular matrix (ECM), highlighting an essential role of ECM in the tumorigenesis and progress of HCC. However, the determinants of ECM in HCC are poorly defined. Here, we show that nuclear receptor RORγ is highly expressed and amplified in HCC tumors. RORγ functions as an essential activator of the matrisome program via directly driving the expression of major ECM genes in HCC cells. Elevated RORγ increases fibronectin-1 deposition, cell-matrix adhesion, and collagen production, creating a favorable microenvironment to boost liver cancer metastasis. Moreover, RORγ antagonists effectively inhibit tumor growth and metastasis in multiple HCC xenografts and immune-intact models, and they effectively sensitize HCC tumors to sorafenib therapy in mice. Notably, elevated RORγ expression is associated with ECM remodeling and metastasis in patients with HCC. Taken together, we identify RORγ as a key player of ECM remodeling in HCC and as an attractive therapeutic target for advanced HCC.


Asunto(s)
Carcinoma Hepatocelular , Neoplasias Hepáticas , Humanos , Animales , Ratones , Carcinoma Hepatocelular/patología , Neoplasias Hepáticas/metabolismo , Línea Celular Tumoral , Sorafenib , Colágeno/metabolismo , Microambiente Tumoral
4.
Proc Natl Acad Sci U S A ; 119(36): e2120680119, 2022 09 06.
Artículo en Inglés | MEDLINE | ID: mdl-35998224

RESUMEN

The systemic immune response to viral infection is shaped by master transcription factors, such as NF-κB, STAT1, or PU.1. Although long noncoding RNAs (lncRNAs) have been suggested as important regulators of transcription factor activity, their contributions to the systemic immunopathologies observed during SARS-CoV-2 infection have remained unknown. Here, we employed a targeted single-cell RNA sequencing approach to reveal lncRNAs differentially expressed in blood leukocytes during severe COVID-19. Our results uncover the lncRNA PIRAT (PU.1-induced regulator of alarmin transcription) as a major PU.1 feedback-regulator in monocytes, governing the production of the alarmins S100A8/A9, key drivers of COVID-19 pathogenesis. Knockout and transgene expression, combined with chromatin-occupancy profiling, characterized PIRAT as a nuclear decoy RNA, keeping PU.1 from binding to alarmin promoters and promoting its binding to pseudogenes in naïve monocytes. NF-κB-dependent PIRAT down-regulation during COVID-19 consequently releases a transcriptional brake, fueling alarmin production. Alarmin expression is additionally enhanced by the up-regulation of the lncRNA LUCAT1, which promotes NF-κB-dependent gene expression at the expense of targets of the JAK-STAT pathway. Our results suggest a major role of nuclear noncoding RNA networks in systemic antiviral responses to SARS-CoV-2 in humans.


Asunto(s)
COVID-19 , Regulación de la Expresión Génica , Monocitos , ARN Largo no Codificante , SARS-CoV-2 , Alarminas/genética , COVID-19/genética , COVID-19/inmunología , Humanos , Quinasas Janus/genética , Monocitos/inmunología , FN-kappa B/genética , ARN Largo no Codificante/genética , ARN Largo no Codificante/metabolismo , RNA-Seq , SARS-CoV-2/inmunología , Factores de Transcripción STAT/genética , Transducción de Señal/genética , Análisis de la Célula Individual
5.
Plant Mol Biol ; 114(1): 14, 2024 Feb 07.
Artículo en Inglés | MEDLINE | ID: mdl-38324190

RESUMEN

Excessive cadmium in rice grain in agricultural production is an important issue to be addressed in some southern regions of China. In this study, we constructed transgenic rice overexpressing OsVIT1 and OsVIT2 driven by 35S promoter in the cultivar ZH11. Compared with ZH11, OsVIT1 expression in leaves was significantly increased by 3-6.6 times and OsVIT2 expression in leaves was significantly increased by 2-2.5 times. Hydroponic experiments showed that overexpression of OsVIT1 and OsVIT2 increased the tolerance to Fe deficiency, significantly reduced Cd content in shoot and xylem sap, and had no effect on Cd tolerance in rice. Two years of field trials showed that the Fe content in the grain of OsVIT1 and OsVIT2 overexpressed materials was significantly reduced by 20-40% and the straw Fe content was significantly increased by 10-45%, and the grain Fe content distribution ratio was significantly decreased and the straw Fe distribution ratio was significantly increased compared with the wild type. The OsVIT1 and OsVIT2 overexpressed materials significantly reduced the Cd content of grain by 40-80% and the Cd content of straws by 37-77%, and the bioconcentration factor of Cd was significantly reduced in both grains and straw of OsVIT1 and OsVIT2 overexpressed materials. Overexpression of OsVIT1 and OsVIT2 did not affect the concentration of other metal ions in rice straw and grain. qRT-PCR analysis showed that the expression of the low affinity cation transporter OsLCT1 was significantly downregulated in the OsVIT1 and OsVIT2 overexpressed materials. In conclusion, overexpression of OsVIT1 and OsVIT2 reduced Cd accumulation in straw and grains, providing a strategy for Cd reduction in rice.


Asunto(s)
Cadmio , Oryza , Hojas de la Planta , Agricultura , China , Grano Comestible , Proteínas de Transporte de Membrana
6.
BMC Med ; 22(1): 278, 2024 Jul 02.
Artículo en Inglés | MEDLINE | ID: mdl-38956533

RESUMEN

BACKGROUND: APRI and FIB-4 scores are used to exclude clinically significant fibrosis (defined as stage ≥ F2) in patients with chronic viral hepatitis. However, the cut-offs for these scores (generated by Youden indices) vary between different patient cohorts. This study aimed to evaluate whether serum dithiothreitol-oxidizing capacity (DOC), i.e., a surrogate test of quiescin sulfhydryl oxidase-1, which is a matrix remodeling enzyme, could be used to non-invasively identify significant fibrosis in patients with various chronic liver diseases (CLDs). METHODS: Diagnostic performance of DOC was compared with APRI and FIB-4 for identifying significant fibrosis. ROC curve analyses were undertaken in: a) two chronic hepatitis B (CHB) cohorts, independently established from hospitals in Wenzhou (n = 208) and Hefei (n = 120); b) a MASLD cohort from Wenzhou hospital (n = 122); and c) a cohort with multiple CLD etiologies (except CHB and MASLD; n = 102), which was identified from patients in both hospitals. Cut-offs were calculated using the Youden index. All CLD patients (n = 552) were then stratified by age for ROC curve analyses and cut-off calculations. RESULTS: Stratified by CLD etiology or age, ROC curve analyses consistently showed that the DOC test was superior to APRI and FIB-4 for discriminating between clinically significant fibrosis and no fibrosis, when APRI and FIB-4 showed poor/modest diagnostic performance (P < 0.05, P < 0.01 and P < 0.001 in 3, 1 and 3 cohort comparisons, respectively). Conversely, the DOC test was equivalent to APRI and FIB-4 when all tests showed moderate/adequate diagnostic performances (P > 0.05 in 11 cohort comparisons). DOC had a significant advantage over APRI or FIB-4 scores for establishing a uniform cut-off independently of age and CLD etiology (coefficients of variation of DOC, APRI and FIB-4 cut-offs were 1.7%, 22.9% and 47.6% in cohorts stratified by CLD etiology, 2.0%, 26.7% and 29.5% in cohorts stratified by age, respectively). The uniform cut-off was 2.13, yielded from all patients examined. Surprisingly, the uniform cut-off was the same as the DOC upper limit of normal with a specificity of 99%, estimated from 275 healthy control individuals. Hence, the uniform cut-off should possess a high negative predictive value for excluding significant fibrosis in primary care settings. A high DOC cut-off with 97.5% specificity could be used for detecting significant fibrosis (≥ F2) with an acceptable positive predictive value (87.1%). CONCLUSIONS: This proof-of-concept study suggests that the DOC test may efficiently rule out and rule in significant liver fibrosis, thereby reducing the numbers of unnecessary liver biopsies. Moreover, the DOC test may be helpful for clinicians to exclude significant liver fibrosis in the general population.


Asunto(s)
Biomarcadores , Ditiotreitol , Cirrosis Hepática , Humanos , Cirrosis Hepática/diagnóstico , Cirrosis Hepática/sangre , Masculino , Persona de Mediana Edad , Biomarcadores/sangre , Femenino , Adulto , Anciano , Oxidación-Reducción , Curva ROC , Estudios de Cohortes , Oxidorreductasas actuantes sobre Donantes de Grupos Sulfuro/sangre , Prueba de Estudio Conceptual
7.
New Phytol ; 241(5): 2108-2123, 2024 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-38155438

RESUMEN

Plants evolved sophisticated machineries to monitor levels of external nitrogen supply, respond to nitrogen demand from different tissues and integrate this information for coordinating its assimilation. Although roles of inorganic nitrogen in orchestrating developments have been studied in model plants and crops, systematic understanding of the origin and evolution of its assimilation and signaling machineries remains largely unknown. We expanded taxon samplings of algae and early-diverging land plants, covering all main lineages of Archaeplastida, and reconstructed the evolutionary history of core components involved in inorganic nitrogen assimilation and signaling. Most components associated with inorganic nitrogen assimilation were derived from the ancestral Archaeplastida. Improvements of assimilation machineries by gene duplications and horizontal gene transfers were evident during plant terrestrialization. Clusterization of genes encoding nitrate assimilation proteins might be an adaptive strategy for algae to cope with changeable nitrate availability in different habitats. Green plants evolved complex nitrate signaling machinery that was stepwise improved by domains shuffling and regulation co-option. Our study highlights innovations in inorganic nitrogen assimilation and signaling machineries, ranging from molecular modifications of proteins to genomic rearrangements, which shaped developmental and metabolic adaptations of plants to changeable nutrient availability in environments.


Asunto(s)
Nitratos , Nitrógeno , Nitratos/metabolismo , Nitrógeno/metabolismo , Transducción de Señal , Productos Agrícolas/metabolismo
8.
New Phytol ; 241(3): 1250-1265, 2024 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-38009305

RESUMEN

Sugar transporter proteins (STPs) play critical roles in regulating plant stress tolerance, growth, and development. However, the role of STPs in regulating crop yield is poorly understood. This study elucidates the mechanism by which knockout of the sugar transporter OsSTP15 enhances grain yield via increasing the tiller number in rice. We found that OsSTP15 is specifically expressed in the shoot base and vascular bundle sheath of seedlings and encodes a plasma membrane-localized high-affinity glucose efflux transporter. OsSTP15 knockout enhanced sucrose and trehalose-6-phosphate (Tre6P) synthesis in leaves and improved sucrose transport to the shoot base by inducing the expression of sucrose transporters. Higher glucose, sucrose, and Tre6P contents were observed at the shoot base of stp15 plants. Transcriptome and metabolome analyses of the shoot base demonstrated that OsSTP15 knockout upregulated the expression of cytokinin (CK) synthesis- and signaling pathway-related genes and increased CK levels. These findings suggest that OsSTP15 knockout represses glucose export from the cytoplasm and simultaneously enhances sugar transport from source leaves to the shoot base by promoting the synthesis of sucrose and Tre6P in leaves. Subsequent accumulation of glucose, sucrose, and Tre6P in the shoot base promotes tillering by stimulating the CK signaling pathway.


Asunto(s)
Oryza , Oryza/metabolismo , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Proteínas de Transporte de Membrana/genética , Proteínas de Transporte de Membrana/metabolismo , Grano Comestible , Glucosa/metabolismo , Sacarosa/metabolismo , Azúcares/metabolismo
9.
New Phytol ; 242(2): 687-699, 2024 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-38396376

RESUMEN

The effect of pathogens on host diversity has attracted much attention in recent years, yet how the influence of pathogens on individual plants scales up to affect community-level host diversity remains unclear. Here, we assessed the effects of foliar fungal pathogens on plant growth and species richness using allometric growth theory in population-level and community-level foliar fungal pathogen exclusion experiments. We calculated growth scaling exponents of 24 species to reveal the intraspecific size-dependent effects of foliar fungal pathogens on plant growth. We also calculated the intercepts to infer the growth rates of relatively larger conspecific individuals. We found that foliar fungal pathogens inhibited the growth of small conspecific individuals more than large individuals, resulting in a positive allometric growth. After foliar fungal pathogen exclusion, species-specific growth scaling exponents and intercepts decreased, but became positively related to species' relative abundance, providing a growth advantage for individuals of abundant species with a higher growth scaling exponent and intercept compared with rare species, and thus reduced species diversity. By adopting allometric growth theory, we elucidate the size-dependent mechanisms through which pathogens regulate species diversity and provide a powerful framework to incorporate antagonistic size-dependent processes in understanding species coexistence.


Asunto(s)
Hongos , Plantas , Plantas/microbiología , Hongos/patogenicidad
10.
Plant Physiol ; 193(3): 1987-2002, 2023 Oct 26.
Artículo en Inglés | MEDLINE | ID: mdl-37527482

RESUMEN

The vacuole is an important organelle for nitrate storage, and the reuse of vacuolar nitrate under nitrate starvation helps plants adapt to low-nitrate environments. CHLORIDE CHANNEL-b (CLC-b) in the vacuolar membrane is a nitrate transporter; however, its regulation and effects on nitrate efflux have not been established. Here, we evaluated CLC-b expression and its effects on physiological parameters under low nitrate conditions. CLC-b expression increased significantly in the roots of wild-type Arabidopsis (Arabidopsis thaliana) Col-0 under nitrate starvation. Under low nitrate, clcb mutants showed reductions in chlorophyll content and xylem sap nitrate concentration, shoot/root nitrate ratios, shoot/root total N ratios, and biomass. CLC-b-overexpression yielded opposite phenotypes and increased nitrogen use efficiency. CLC-b mutants showed elevated chlorate tolerance and an increased proportion of vacuolar nitrate relative to the total protoplast nitrate content as compared to the wild type. Yeast 1-hybrid, EMSA, and chromatin immunoprecipitation (ChIP) experiments showed that HRS1 HOMOLOG2 (HHO2), the expression of which is downregulated under low nitrate, binds directly to the promoter of CLC-b. clcb/hho2 double mutants and HHO2-overexpressing clcb plants had similar phenotypes under low nitrate to those of clcb single mutants. Thus, CLC-b mediates vacuolar nitrate efflux and is negatively regulated by HHO2, providing a theoretical basis for improving plant adaptability to low nitrate.


Asunto(s)
Proteínas de Arabidopsis , Arabidopsis , Arabidopsis/metabolismo , Nitratos/metabolismo , Nitrógeno/metabolismo , Vacuolas/metabolismo , Canales de Cloruro/genética , Canales de Cloruro/metabolismo , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Plantas/metabolismo , Raíces de Plantas/genética , Raíces de Plantas/metabolismo
11.
Glob Chang Biol ; 30(1): e17033, 2024 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-38273530

RESUMEN

Global climate warming could affect the methane (CH4 ) and nitrous oxide (N2 O) fluxes between soils and the atmosphere, but how CH4 and N2 O fluxes respond to whole-soil warming is unclear. Here, we for the first time investigated the effects of whole-soil warming on CH4 and N2 O fluxes in an alpine grassland ecosystem on the Tibetan Plateau, and also studied the effects of experimental warming on CH4 and N2 O fluxes across terrestrial ecosystems through a global-scale meta-analysis. The whole-soil warming (0-100 cm, +4°C) significantly elevated soil N2 O emission by 101%, but had a minor effect on soil CH4 uptake. However, the meta-analysis revealed that experimental warming did not significantly alter CH4 and N2 O fluxes, and it may be that most field warming experiments could only heat the surface soils. Moreover, the warming-induced higher plant litter and available N in soils may be the main reason for the higher N2 O emission under whole-soil warming in the alpine grassland. We need to pay more attention to the long-term response of greenhouse gases (including CH4 and N2 O fluxes) from different soil depths to whole-soil warming over year-round, which could help us more accurately assess and predict the ecosystem-climate feedback under realistic warming scenarios in the future.


Asunto(s)
Ecosistema , Suelo , Pradera , Dióxido de Carbono/análisis , Óxido Nitroso/análisis , Metano
12.
Phys Chem Chem Phys ; 26(6): 5045-5058, 2024 Feb 07.
Artículo en Inglés | MEDLINE | ID: mdl-38258528

RESUMEN

Recently, a magnetic semiconducting NiI2 monolayer was successfully fabricated. To obtain richer magneto-electronic properties and find new physics for NiI2, we studied the zigzag-type NiI2 nanoribbon (ZNiI2NR) with edges modified by different concentrations of H and/or O atoms. Results show that these ribbons hold a higher energy stability, thermal stability, and magnetic stability, and the Curie temperature can be increased to 143 from 15 K for the bare-edged ribbons. They feature a half-semiconductor, bipolar magnetic semiconductor, or half-metal, depending on the edge-terminated atomic species and concentrations, and are closely related to the ribbon edge states, impurity bands or hybridized bands. By applying strain or an electric field, ribbons can achieve a reversible multi-magnetic phase transition among a bipolar magnetic semiconductor, half-semiconductor, half-metal, and magnetic metal. This is because strain changes the Ni-I bond length, resulting in a variation of bond configurations (weight of ionic and covalent bonds) and the number of unpaired electrons. The compressive strain can increase the Curie temperature because it makes the edged Ni-I-Ni bond angle closer to 90°, leading to the FM d-p-d superexchange interaction being increased. The electric field varies the magnetic phase because it alters the electrostatic potential of the ribbon edges, and the Curie temperature is enhanced under the electric field because the ribbon is changed to a metallic state (half-metal or magnetic metal), in which the magnetic Ni atoms satisfy the Stoner criterion and hold a large magnetic exchange coefficient and electron state density at the Fermi surface.

13.
Phys Chem Chem Phys ; 26(5): 4218-4230, 2024 Jan 31.
Artículo en Inglés | MEDLINE | ID: mdl-38230672

RESUMEN

Recently, single-layer PtSe2, possessing high carrier mobility and optical response, has been successfully fabricated. To further expand its application scope and find new physics, in this work, we functionalized it via the adsorption of non-metallic atoms X (X = H, B, C, N, O, and F) to form hybrid systems X-PtSe2, and their geometrical, mechanical, electronic, and optical properties as well as strain tuning effects were studied deeply. Calculations show that the energy stability of X-PtSe2 systems is significantly enhanced, and they also hold higher thermal and mechanical stability. Particularly, X-PtSe2 systems present excellent in-plane tenacity and out-of plane stiffness against deformations, which make them more applicable for designing nanodevices. Intrinsic PtSe2 is a semiconductor, while the X-PtSe2 system can be a band-gap narrowed semiconductor or metal, thus expanding the application scope for PtSe2, and the odd-even effect of electronic phase variation related to the atomic number is found. Besides, the wavelength range of optical adsorption is increased in X-PtSe2 systems, implying that its optical response region is wide, providing more options for developing optoelectronic devices. Moreover, it is shown that strain can flexibly tune the electronic property of X-PtSe2 systems, especially enhancing the optical absorption ability substantially, beneficial for their applications in solar devices.

14.
Phys Chem Chem Phys ; 26(27): 18865-18870, 2024 Jul 10.
Artículo en Inglés | MEDLINE | ID: mdl-38946600

RESUMEN

Using gas phase Fourier-transform microwave spectroscopy complemented by theoretical analysis, this study delivers a comprehensive depiction of the physical origin of the 'n → π* interaction' between CO2 and acrolein, one of the most reactive aldehydes. Three distinct isomers of the acrolein-CO2 complex, linked through a C⋯O tetrel bond (or n → π* interaction) and a C-H⋯O hydrogen bond, have been unambiguously identified in the pulsed jet. Relative intensity measurements allowed estimation on the population ratio of the three isomers to be T1/T2/C1 ≈ 25/5/1. Advanced theoretical analyses were employed to elucidate the intricacies of the noncovalent interactions within the examined complex. This study not only sheds light on the molecular underpinnings of n → π* interactions but also paves the way for future exploration in carbon dioxide capture and utilization, leveraging the fundamental principles uncovered in the study of acrolein-carbon dioxide interactions.

15.
Environ Res ; 243: 117668, 2024 Feb 15.
Artículo en Inglés | MEDLINE | ID: mdl-38007082

RESUMEN

In recent years, one of the most important and innovative policy initiatives introduced by the Chinese government in the field of environmental protection and ecological civilization construction is the Central Environmental Protection Inspection (CEPI). CEPI is seen as a vital tool to encourage local implementation of environmental protection responsibility. Over the course of its operation (eight years), CEPI has transformed from the "campaign" phase to the "convention" phase. It is noted that while provincial governments face a common high-pressure environment created by CEPI, governance scenarios, behaviors, and performance vary across the country significantly. To better understand local governments' environmental governance behaviors under the transformation of CEPI, an integrated analysis framework consisting of two key elements, "central dominance" and "local proactiveness", is constructed based on the central-local interactions under the principal-agent model. Based on this framework, we conducted a multi-case comparative analysis of four classic cases, with the following findings. (1) Along with the operation of CEPI and its transformation, the interaction between the central and local governments leads to four governance scenarios: "control-active cooperation", "control-passive cooperation", "guidance-active promotion", and "guidance-passive promotion". (2) Influenced by various factors such as pressure by the central government, local governments' capabilities and governance motivations, local governments form governance behaviors with varying degrees of proactiveness and autonomy. (3) After examining the governance performance of varying behaviors, it is found that local government's "active promotion" behavior can achieve higher governance effectiveness in the "convention" phase. Therefore, it is of policy implication that local governments should be guided to transit from "passive cooperation" to "active promotion". This paper has important guiding significance for understanding local environmental governance behaviors under strong top-down institutional pressure.


Asunto(s)
Conservación de los Recursos Naturales , Política Ambiental , China , Gobierno
16.
Environ Res ; 244: 117912, 2024 Mar 01.
Artículo en Inglés | MEDLINE | ID: mdl-38097058

RESUMEN

Energy transition policies are of great significance in adjusting the structure of energy supply and demand and coping with climate change. The new energy demonstration city pilot (NEDCP) policy, as an important pilot project in China's energy transition process, lacks a scientific assessment of the carbon reduction effect of the NEDCP policy and an in-depth explanation of the mechanism of the NEDCP. Based on panel data of 209 Chinese cities at the prefectural and higher levels from 2007 to 2019, this study takes the NEDCP policy as a quasi-natural experiment, using a difference-in-differences model combined with firm-level data to identify the impact of the NEDCP policy on urban carbon dioxide (CO2) emissions. This study analyzes the impact of heterogeneity of urban characteristics on the policy effect from multiple perspectives, and further investigates its mechanism. The conclusions are shown in the following aspects. (1) The implementation of the NEDCP policy decreases urban CO2 emissions significantly. Meanwhile, a series of robustness tests, including the instrumental variables method, propensity score matching difference-in-differences method, placebo test, exclusion of policy interference test, and machine learning method, support this conclusion. (2) The NEDCP policy achieves carbon reduction effects mainly through scale and structure effects. (3) The results of the heterogeneity test show that the NEDCP policy is more effective in cities with higher administrative levels, energy-demanding cities, cities in the southeast of Hu-line, and cities with a higher degree of nationalization. Therefore, the Chinese government should summarize the implementation experience of the NEDCP policy and expand its scope of application. The evaluation of the NEDCP policy in China has important reference value for the energy transition of other developing countries.


Asunto(s)
Dióxido de Carbono , Políticas , Ciudades , Proyectos Piloto , China , Desarrollo Económico
17.
Environ Res ; 244: 117967, 2024 Mar 01.
Artículo en Inglés | MEDLINE | ID: mdl-38109964

RESUMEN

The growing demand for lithium-ion batteries for portable electronics and electric vehicles results in a booming lithium battery market, leading to a concomitant increase in spent graphite. This research investigated the potential impacts of spent graphite on environmental and human health using standardized toxicity extraction and Life Cycle Impact Assessment models. The spent graphite samples were classified as hazardous waste due to the average nickel content of 337.14 mg/L according to Chinese regulations. Besides, cadmium and fluorine were the other elements that exceeded the regulations threshold. Easily ignored aluminum and heavy metal cobalt are other harmful elements according to the results of Life Cycle Impact Assessments. All the metallic harmful elements mainly exist in a transferable state. Thermogravimetry infrared spectrometry coupled with mass spectrometry was employed to recognize the emitted gases and explore gas emission behavior. Inorganic gases of CO, H2S, SO2, SO3, oxynitride, HCl, and fluoride-containing gases were detected. Sulfur-containing gases released from spent graphite were contributed by the residual sulfuric acid after leaching. The correlation between the evolution of emitted gases and the heating schedule was established simultaneously. The research comprehensively illustrates the pollution of spent graphite and provides assistance for the design of green recycling schemes for spent graphite.


Asunto(s)
Grafito , Metales Pesados , Humanos , Litio , Reciclaje/métodos , Suministros de Energía Eléctrica , Gases
18.
Platelets ; 35(1): 2337255, 2024 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-38630028

RESUMEN

Exosomes carry large cargo of proteins, lipids, and nucleic acids, serving as versatile biomarkers for disease diagnosis and vehicles for drug delivery. However, up to date, no well recognized standard procedures for exosome storage were available for clinical application. This study aimed to determine the optimal storage conditions and the anticoagulants for plasma-derived exosome isolation. Fresh whole blood samples were collected from healthy participants and preserved in four different anticoagulants including sodium citrate (SC1/4), sodium citrate (SC1/9), lithium heparin (LH), or Ethylenediamine tetraacetic acid (EDTA), respectively. Exosomes were extracted from the plasma by differential ultracentrifugation and stored at three different temperatures, 4°C, -20°C or - 80°C for a duration ranging from one week to six months. All plasma samples for storage conditions comparison were pretreated with LH anticoagulant. Exosome features including morphological characteristics, pariticles size diameter, and surface protein profiles (TSG101, CD63, CD81, CD9, CALNEXIN) were assessed by transmission electron microscopy, Nanoparticle Tracking Analysis, and Western Blotting, respectively. Exosomes preserved in LH and SC1/4 group tended to remain intact microstructure with highly abundant protein biomarkers. Exosomes stored at 4°C for short time were prone to be more stable compared to thos at -80°C. Exosomes stored in plasma were superior in terms of ultrastructure, size diameter and surface protein expression to those stored in PBS. In conclusion, plasma-dervied exosome characteristics strictly depend on the anticoagulants and storage temperature and duration.


What is the context? Effective isolation of exosomes is a prerequisite for subsequent investigation into its involvemnt in disease development as well as potentialtherapeutic applications.Anticoagulants, storage temperature and durations might change the microscopical structure, integrity and also the stability of plasma-derived exosomes. However, no internationally recognized standard of exosome storage procedure was available for clinical use.What is new? Our finding evaluated the effect of anticoagulants and storage on plasma exosome characteristics.Exosomes isolated from plasma preserved with Li-heparin and sodium citrate (1/4) showed better physical properties and surface marker protein expression.Isolated exosomes appeared more stable in a short time for 4°C compared to −80°C. Storage of exosomes in plasma showed better physical properties and surface marker protein expression than in PBS.What is the impact? Our findings inform the significance of standardizing procedure of exosome isolation and preservation.


Asunto(s)
Exosomas , Humanos , Citrato de Sodio , Temperatura , Anticoagulantes/farmacología , Anticoagulantes/uso terapéutico , Heparina , Proteínas de la Membrana , Biomarcadores
19.
BMC Musculoskelet Disord ; 25(1): 531, 2024 Jul 11.
Artículo en Inglés | MEDLINE | ID: mdl-38987691

RESUMEN

BACKGROUND: The treatment of the displaced proximal humerus fractures (PHF) still facing a lot of unsolved problems. The aim of this study was to evaluate the clinical effect of MultiLoc nails for the treatment of PHF and present outcomes of patients with different Neer's classification and reduction quality. METHODS: Adult patients with PHFs were recruited and treated with MultiLoc nail. Intraoperative data, radiographic and functional outcomes, as well as occurrence of postoperative complications were assessed. RESULTS: 48 patients met inclusion and exclusion criteria and were included in this study. The DASH Score were 32.2 ± 3.1 points at 12 months, and 37.3 ± 2.5 points at the final follow-up. The mean ASES score at 12 months and final follow-up were 74.4 ± 6.2 and 78.8 ± 5.1, respectively. The mean CM Score in all 48 patients reached 68 ± 6.4 points at the final follow-up, relative side related CM Score 75.2 ± 7.7% of contralateral extremity. The incidence rate of complications was 20.8%. Patients with fracture mal-union, adhesive capsulitis were observed but no secondary surgeries were performed. There was no significantly difference of DASH Score 12 months after surgery and at the last follow-up among patients with different Neer's classification or reduction quality. However, functional outcomes such as ASES score and CM score were significantly influenced by severity of fracture and the quality of fracture reduction. CONCLUSIONS: Our study demonstrated that MultiLoc nails is well suited for proximal humeral fractures, with satisfactory health status recovery, good radiographic results, positive clinical outcomes and low rates of complications. The treatment for four part PHF still faces great challenges. Accurate fracture reduction was an important factor for good functional result.


Asunto(s)
Clavos Ortopédicos , Fijación Intramedular de Fracturas , Complicaciones Posoperatorias , Fracturas del Hombro , Humanos , Fracturas del Hombro/cirugía , Fracturas del Hombro/diagnóstico por imagen , Masculino , Femenino , Persona de Mediana Edad , Fijación Intramedular de Fracturas/métodos , Fijación Intramedular de Fracturas/instrumentación , Fijación Intramedular de Fracturas/efectos adversos , Anciano , Resultado del Tratamiento , Complicaciones Posoperatorias/etiología , Complicaciones Posoperatorias/epidemiología , Adulto , Estado de Salud , Estudios de Seguimiento , Radiografía , Estudios Retrospectivos
20.
Sensors (Basel) ; 24(8)2024 Apr 09.
Artículo en Inglés | MEDLINE | ID: mdl-38676010

RESUMEN

Aiming at the problems of target detection models in traffic scenarios including a large number of parameters, heavy computational burden, and high application cost, this paper introduces an enhanced lightweight real-time detection algorithm, which exhibits higher detection speed and accuracy for vehicle detection. This paper considers the YOLOv7 algorithm as the benchmark model, designs a lightweight backbone network, and uses the MobileNetV3 lightweight network to extract target features. Inspired by the structure of SPPF, the spatial pyramid pooling module is reconfigured by incorporating GSConv, and a lightweight SPPFCSPC-GS module is designed, aiming to minimize the quantity of model parameters and enhance the training speed even further. Furthermore, the CA mechanism is integrated to enhance the feature extraction capability of the model. Finally, the MPDIoU loss function is utilized to optimize the model's training process. Experiments showcase that the refined YOLOv7 algorithm can achieve 98.2% mAP on the BIT-Vehicle dataset with 52.8% fewer model parameters than the original model and a 35.2% improvement in FPS. The enhanced model adeptly strikes a finer equilibrium between velocity and precision, providing favorable conditions for embedding the model into mobile devices.

SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA