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The analysis of the tree radial growth response to climate is crucial for dendroclimatological research. However, the response relationships between tree-ring indices and climatic factors at different timescales are not yet clear. In this study, the tree-ring width of Huashan pine (Pinus armandii) from Huashan in the Qinling Mountains, north-central China, was used to explore the response differences of tree growth to climatic factors at daily, pentad (5 days), dekad (10 days) and monthly timescales. Correlation function and linear regression analysis were applied in this paper. The tree-ring width showed a more sensitive response to daily and pentad climatic factors. With the timescale decreasing, the absolute value of the maximum correlation coefficient between the tree-ring data and precipitation increases as well as temperature (mean, minimum and maximum temperature). Compared to the other three timescales, pentad was more suitable for analysing the response of tree growth to climate. Relative to the monthly climate data, the association between the tree-ring data and the pentad climate data was more remarkable and accurate, and the reconstruction function based on the pentad climate was also more reliable and stable. We found that the major climatic factor limiting Huashan pine growth was the precipitation of pentads 20-35 (from April 6 to June 24) rather than the well-known April-June precipitation. The pentad was also proved to be a better timescale for analysing the climate and tree growth in the western and eastern Qinling Mountains. The formation of the earlywood density of Chinese pine (Pinus tabulaeformis) from Shimenshan in western Qinling was mainly affected by the maximum temperature of pentads 28-32 (from May 16 to June 9). The maximum temperature of pentads 28-33 (from May 16 to June 14) was the major factor affecting the ring width of Chinese pine from Shirenshan in eastern Qinling.

Given growing concerns about global climate change, it is critical to understand both historical and current shifts in the hydroclimate, particularly in regions critically entwined with global circulation. The Tibetan Plateau, the Earth’s largest and highest plateau, is a nexus for global atmospheric processes, significantly influencing East Asian hydroclimate dynamics through the synergy of the Asian Monsoon and the Westerlies. Yet, understanding historical and recent hydroclimate fluctuations and their wide-ranging ecological and societal consequences remains challenging due to short instrumental observations and partly ambiguous proxy reconstructions. Here, we present a precisely-dated 3476-year precipitation reconstruction derived from tree-ring δ 18 O data on the Tibetan Plateau, representing one of the few multi-millennia-long annually-resolved terrestrial δ 18 O records to date. Our findings reveal that the 20 th  century drought extremes are severe within the past three millennia, and likely linked to the weakening of both the Asian Monsoon and Westerlies due to anthropogenic aerosol emissions. Additionally, our analyses identified three distinct stages (110 BC–AD 280, AD 330–770 and AD 950–1300) characterized by shifts toward arid hydroclimate conditions, corresponding to significant social unrest and dynasty collapses, which underscores the potential societal impacts of severe hydroclimatic shifts. An annually resolved 3476-year tree-ring record from the Tibetan Plateau reveals severe 20 th  century droughts and highlights the interplay between the Asian Monsoon and Westerlies. Droughts are often linked to the collapse of dynasties.

The far-reaching impacts of central Pacific El Niño events on global climate differ appreciably from those associated with eastern Pacific El Niño events. Central Pacific El Niño events may become more frequent in coming decades as atmospheric greenhouse gas concentrations rise, but the instrumental record of central Pacific sea-surface temperatures is too short to detect potential trends. Here we present an annually resolved reconstruction of NIÑO4 sea-surface temperature, located in the central equatorial Pacific, based on oxygen isotopic time series from Taiwan tree cellulose that span from 1190 AD to 2007 AD. Our reconstruction indicates that relatively warm Niño4 sea-surface temperature values over the late twentieth century are accompanied by higher levels of interannual variability than observed in other intervals of the 818-year-long reconstruction. Our results imply that anthropogenic greenhouse forcing may be driving an increase in central Pacific El Niño-Southern Oscillation variability and/or its hydrological impacts, consistent with recent modelling studies. El Niño events in the Central Pacific may be changing due to climate change, but long records to support this are lacking. Here, the authors present sea surface temperature reconstructions from tree cellulose for the last 800 years which suggest the variability of Central Pacific El Niño events has increased.

In the context of global warming, the “divergence problem” phenomenon in the climate response of tree growth has been observed. Here, we use tree-ring stable oxygen isotopes (δ 18 O) to examine the response under current warming in Tsuga chinensis Pritz. and Pinus tabulaeformis Carr. growing on the south slope (SS) and north slope (NS) of the Qinling Mountains, a boundary between subtropical and warm temperate zones in China. Both δ 18 O series are significantly correlated with several hydroclimate reconstructions in the surrounding area since 1750, suggesting that tree-ring δ 18 O could capture large-scale characteristics of climate change in the Qinling Mountains. However, a difference arises in the two δ 18 O series since the early 1980s. At the SS site, the increasing δ 18 O is closely related to the increased warming (0.30℃/year) from 1981. This result mainly because temperature is the most significant climate factor (r = 0.465, n = 51, p < 0.001) in determining tree-ring δ 18 O by affecting the δ 18 O of soil water before and after the increased warming at the SS site. Although the warming trend is also significant (0.31℃/year) at the NS site since 1981, the δ 18 O variation shows no obvious fluctuation, which may indicate that relative humidity is the dominant controlling factor (r=-0.603, n = 48, p < 0.001) but not temperature for the δ 18 O of Pinus tabulaeformis . The results imply that tree-ring δ 18 O is still sensitive to its dominant climatic controlling factor under the current warming, suggesting that it has the potential to infer past climate change by using tree-ring δ 18 O in a future warming scenario.

Acetaminophen (APAP) overdose is a common cause of drug-induced liver injury (DILI), which can lead to sterile inflammation and progress to acute liver failure and even death. However, there are currently limited therapeutic options available. Iinterleukin-37 (IL-37) is considered as an anti-inflammatory cytokine. The role and novel mechanism of IL-37 on DILI are still unknown. Male C57BL/6 mice were pretreated with IL-37 for 2 h prior to intraperitoneal injection of acetaminophen (APAP). Hepatic function was assessed by measuring serum levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST), and lactate dehydrogenase (LDH). Liver tissue damage was evaluated via hematoxylin and eosin (H&E) staining. The inflammatory response was characterized by immunohistochemical (IHC) analysis of myeloperoxidase (MPO) and lymphocyte antigen 6 complex locus G (Ly6G), and the levels of interleukin-6 (IL-6), IL-10, transforming growth factor-beta 1 (TGF-β1), and tumor necrosis factor-alpha (TNF-α) in liver tissue. Oxidative stress status was determined by measuring superoxide dismutase (SOD), malondialdehyde (MDA), and glutathione (GSH) levels. CYP2E1 mRNA expression was analyzed using qPCR. Protein expression of phosphorylated p38 (pP38), phosphorylated extracellular signal-regulated kinase 1/2 (pERK1/2), and phosphorylated p65 (pP65) was evaluated by Western blotting. Compared to the model group without recombinant human IL-37 treatment, the model + IL-37 group exhibited significantly attenuated liver injury, characterized by reduced neutrophil infiltration, decreased levels of pro-inflammatory mediators IL-6 and TNF-α, and elevated levels of the anti-inflammatory cytokines IL-10 and TGF-β1. The levels of pp38, pERK 1/2 , and pp65 in liver tissue were significantly suppressed in the Model + IL-37 group compared to the Model group at 24 h. Furthermore, MDA levels were significantly lower in the IL-37-treated group relative to the model group, while SOD activity showed no significant difference. Our results also indicate that neither CYP2E1 mRNA relative expression nor GSH levels differed significantly between the model group and the IL-37-treated group at either 4 h or 24 h after APAP exposure. IL-37 has a significant protective effect against acetaminophen-induced liver injury (AILI) by suppressing the inflammatory response involved in the MAPK-NF-κB/p65 signalling pathway. Our study suggests IL-37 as a potential therapeutic strategy for DILI.

Background The ability of antimicrobial agents to affect microbial adherence to eukaryotic cell surfaces is a promising antivirulence strategy for combating the global threat of antimicrobial resistance. Inadequate use of antimicrobials has led to widespread instances of suboptimal antibiotic concentrations around infection sites. Therefore, we aimed to examine the varying effect of an antimicrobial peptidase lysostaphin (APLss) on staphylococcal adherence to host cells, biofilm biomass formation, and toxin production as a probable method for mitigating staphylococcal virulence. Results Initially, soluble expression in E. coli and subsequent purification by immobilized-Ni 2+ affinity chromatography (IMAC) enabled us to successfully produce a large quantity of highly pure ~ 28-kDa His-tagged mature APLss. The purified protein exhibited potent inhibitory effects against both methicillin-sensitive and methicillin-resistant staphylococcal strains, with minimal inhibitory concentrations (MICs) ranging from 1 to 2 µg/mL, and ultrastructural analysis revealed that APLss-induced concentration-specific changes in the morphological architecture of staphylococcal surface membranes. Furthermore, spectrophotometric and fluorescence microscopy revealed that incubating staphylococcal strains with sub-MIC and MIC of APLss significantly inhibited staphylococcal adherence to human vaginal epithelial cells and biofilm biomass formation. Ultimately, transcriptional investigations revealed that APLss inhibited the expression of agrA (quorum sensing effector) and other virulence genes related to toxin synthesis. Conclusions Overall, APLss dose-dependently inhibited adhesion to host cell surfaces and staphylococcal-associated virulence factors, warranting further investigation as a potential anti-staphylococcal agent with an antiadhesive mechanism of action using in vivo models of staphylococcal toxic shock syndrome.

The historical May-October mean temperature since 1831 was reconstructed based on tree-ring width of Qinghai spruce (Picea crassifolia Kom.) collected on Mt. Dongda, North of the Hexi Corridor in Northwest China. The regression model explained 46.6% of the variance of the instrumentally observed temperature. The cold periods in the reconstruction were 1831-1889, 1894-1901, 1908-1934 and 1950-1952, and the warm periods were 1890-1893, 1902-1907, 1935-1949 and 1953-2011. During the instrumental period (1951-2011), an obvious warming trend appeared in the last twenty years. The reconstruction displayed similar patterns to a temperature reconstruction from the east-central Tibetan Plateau at the inter-decadal timescale, indicating that the temperature reconstruction in this study was a reliable proxy for Northwest China. It was also found that the reconstruction series had good consistency with the Northern Hemisphere temperature at a decadal timescale. Multi-taper method spectral analysis detected some low- and high-frequency cycles (2.3-2.4-year, 2.8-year, 3.4-3.6-year, 5.0-year, 9.9-year and 27.0-year). Combining these cycles, the relationship of the low-frequency change with the Pacific Decadal Oscillation (PDO), North Atlantic Oscillation (NAO) and Southern Oscillation (SO) suggested that the reconstructed temperature variations may be related to large-scale atmospheric-oceanic variations. Major volcanic eruptions were partly reflected in the reconstructed temperatures after high-pass filtering; these events promoted anomalous cooling in this region. The results of this study not only provide new information for assessing the long-term temperature changes in the Hexi Corridor of Northwest China, but also further demonstrate the effects of large-scale atmospheric-oceanic circulation on climate change in Northwest China.

Little is known about the mechanism of climate–vegetation coverage coupled changes in the Tibetan Plateau (TP) region, which is the most climatically sensitive and ecologically fragile region with the highest terrain in the world. This study, using multisource datasets (including satellite data and meteorological observations and reanalysis data) revealed the mutual feedback mechanisms between changes in climate (temperature and precipitation) and vegetation coverage in recent decades in the Hengduan Mountains Area (HMA) of the southeastern TP and their influences on climate in the downstream region, the Sichuan Basin (SCB). There is mutual facilitation between rising air temperature and increasing vegetation coverage in the HMA, which is most significant during winter, and then during spring, but insignificant during summer and autumn. Rising temperature significantly enhances local vegetation coverage, and vegetation greening in turn heats the atmosphere via enhancing net heat flux from the surface to the atmosphere. The atmospheric heating anomaly over the HMA thickens the atmospheric column and increases upper air pressure. The high pressure anomaly disperses downstream via the westerly flow, expands across the SCB, and eventually increases the SCB temperature. This effect lasts from winter to the following spring, which may cause the maximum increasing trend of the SCB temperature and vegetation coverage in spring. These results are helpful for estimating future trends in climate and eco-environmental variations in the HMA and SCB under warming scenarios, as well as seasonal forecasting based on the connection between the HMA eco-environment and SCB climate.

As the capital city of China, Beijing is confronted with significant water scarcity challenges, primarily attributed to its substantial population growth and accelerated industrial expansion. The Miyun Reservoir, which serves as the principal water source for Beijing's domestic supply, is primarily replenished by the White River. Using Chinese pine (Pinus tabuliformis Carr.) tree‐ring samples collected near the upper reaches of river, we analyzed inter‐annual variations in δ18O, to access the variability of reservoir outflow discharge from 1961 to 2018. Statistical analysis revealed a significant positive correlation between tree‐ring δ18O and the mean minimum temperature during February‐March, demonstrating a pronounced “temperature effect” on isotopic fractionation associated with cellulose synthesis. A significant negative correlation was observed between δ18O and summer outflow discharge, primarily driven by the coupled effects of snowmelt dynamics on both hydrological regimes and isotopic partitioning processes. Tree‐ring δ18O record revealed distinct anthropogenic disturbances in outflow discharge patterns during two critical periods: 1976–1985 and 1997–2002, characterized by significant deviations from natural hydrological variability. Outflow discharge was found to be fundamentally modulated by the natural variability of large‐scale atmospheric circulation patterns.

As one of the regions most affected by global climate warming, the Tianshan mountains has experienced several ecological crises, including retreating glaciers and water deficits. Climate warming in these mountains is considered mainly to be caused by increases in minimum temperatures and winter temperatures, while the influence of maximum temperatures is unclear. In this study, a 300-year tree-ring chronology developed from the Western Tianshan Mountains was used to reconstruct the summer (June–August) maximum temperature ( T max6–8 ) variations from 1718 to 2017. The reconstruction explained 53.1% of the variance in the observed T max6–8 . Over the past 300 years, the T max6–8 reconstruction showed clear interannual and decadal variabilities. There was a significant warming trend (0.18 °C/decade) after the 1950s, which was close to the increasing rates of the minimum and mean temperatures. The increase in maximum temperature was also present over the whole Tianshan mountains and its impact on climate warming has increased. The T max6-8 variations in the Western Tianshan mountains were influenced by frequent volcanic eruptions combined with the influence of solar activity and the summer North Atlantic Oscillation. This study reveals that climate warming is significantly influenced by the increase in maximum temperatures and clarifies possible driving mechanisms of temperature variations in the Western Tianshan mountains which should aid climate predictions.