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A highly reliable and selective ethanol gas sensor working in realistic environments based on alpha-Fe2O3 (α-Fe2O3) nanorhombs is developed. The sensor is fabricated by integrating α-Fe2O3 nanorhombs onto a low power microheater based on micro-electro-mechanical systems (MEMS) technology. The α-Fe2O3 nanorhombs, prepared via a solvothermal method, is characterized by transmission electron microscopy (TEM), Raman spectroscopy, x-ray diffraction (XRD), and x-ray photoelectron spectroscopy (XPS). The sensing performances of the α-Fe2O3 sensor to various toxic gases are investigated. The optimum sensing temperature is found to be about 280 °C. The sensor shows excellent selectivity to ethanol. For various ethanol concentrations (1 ppm–20 ppm), the response and recovery times are around 3 s and 15 s at the working temperature of 280 °C, respectively. Specifically, the α-Fe2O3 sensor exhibits a response shift less than 6% to ethanol at 280 °C when the relative humidity (RH) increases from 30% to 70%. The good tolerance to humidity variation makes the sensor suitable for reliable applications in Internet of Things (IoT) in realistic environments. In addition, the sensor shows great long-term repeatability and stability towards ethanol. A possible gas sensing mechanism is proposed. [ABSTRACT FROM AUTHOR]

In this study, we investigated the potential influence of central and eastern Pacific sea surface temperatures (SSTs) on the unstable relationship between earlywood δ18O and climatic factors in the southwestern China from 1902 to 2005. The results show that the strength of the climate signals recorded in the earlywood δ18O series has declined since the late 1970s. This reduction in signal strength may have been caused by the changes in the local hydroclimate, which is associated with the increasing SSTs in the central Pacific Ocean over recent decades. Alongside these increasing SSTs in the central Pacific, southwestern China has experienced more droughts, as well as more severe droughts through the late spring and early summer during the central Pacific (CP) El Niño years than during the eastern Pacific (EP) El Niño years in recent decades. This increased drought frequency may have weakened the response of earlywood δ18O to climate variables. [ABSTRACT FROM AUTHOR]

Stable isotopes in tree rings are increasingly used as proxies for climatic and ecophysiological changes. However, uncertainties remain about the strength and consistency of their response to environmental variation at different temporal (i.e. seasonal to inter-decadal) scales., We developed 5 yr of intra-seasonal and 62 yr of early- and late-wood δ13C and δ18O series of Smith fir ( Abies georgei var. smithii) on the southeastern Tibetan Plateau, and used a process-based forward model to examine the relative importance of environmental and physiological controls on the isotopic data., In this temperate high-altitude region, the response, both δ18O and δ13C, is primarily to variations in relative humidity, but by different processes. In δ18O, the response is via source water δ18O but also arises from leaf water 18O enrichment. In δ13C, the response is via changes in stomatal conductance but is modified by carry-over effects from prior periods., We conclude that tree-ring δ18O may be a more robust climate proxy than δ13C, and δ13C may be more suited to studies of site-related physiological responses to the local environment. [ABSTRACT FROM AUTHOR]

• Vaganov–Shashkin lite was integrated with stochastic antecedent modeling. • Tree-ring width data of 109 conifers in temperate China were analyzed. • Tree-ring width series were clustered into warm-dry, cold-dry, and cold-wet. • Current and antecedent climatic drivers of tree-ring width series were quantified. • Our model improves the simulated results of tree-ring growth in diverse forests. Process modeling of tree growth responses to climate can improve our understanding of the functioning of tree growth under climate change, but these models do not consider so-called memory effects. Further, memory effects are unstudied in temperate forests of China, which is showing high vulnerability to climate warming. Here, we integrate a process-based Vaganov–Shashkin–Lite (VS-Lite) model of tree ring formation with the stochastic antecedent modeling (SAM) approach, to quantify the current and antecedent climatic drivers of the tree-ring width chronologies of 109 conifers in temperate China. Based on climate-response patterns, tree-ring width series were clustered into "warm-dry," "cold-dry," and "cold-wet." The VS-Lite results indicated growth in the "warm-dry" and "cold-dry" sites were primarily constrained by current soil moisture, while growth in the "cold-wet" sites was mainly constrained by cotemporaneous temperature. Compared to VS-Lite alone, we found significant improvements in model fit for the SAM framework in all forest types. Notably, antecedent drivers explained 14%, 11%, and 21% of the growth variations in "warm-dry," "cold-dry," and "cold-wet" sites, respectively, challenging the assertion that long memory is only important in dry forests. Commonality analysis revealed that growth in "cold-dry" and "cold-wet" sites was determined by antecedent climate while growth in the "cold-dry" and "warm-dry" clusters were determined by the endogenous (autoregressive) memory. In "warm-dry" and "cold-wet" sites, growth was significantly affected by antecedent temperature in opposite directions, whereas in the "cold-dry" sites it was affected by antecedent soil moisture conditions and soil moisture-temperature interactions. Our combined process-empirical model demonstrates that memory is prevalent across temperate forests in China and also improves representation of tree growth in diverse forests under novel climate conditions of the future. [Display omitted] [ABSTRACT FROM AUTHOR]

Incursion of the Indian Monsoon flow onto the Qinghai–Tibetan Plateau is an important regional moisture-delivery mechanism, but the causes of intra-seasonal and longer-term variations are poorly understood. We observed a clear intra-seasonal cycle in the oxygen isotope composition ( δ 18 O) of Smith fir ( Abies forrestii var. georgei) growing at two different altitudes (high-elevation site: 29°39′N, 94°42′E, 4200 m a.s.l.; low-elevation site: 29°39′N, 94°43′E, 3800 m a.s.l.) on a SE-facing slope in the Sygera Mountains, southeastern Qinghai–Tibetan Plateau. Mechanistic modeling suggests that δ 18 O of precipitation, which in turn depends on relative humidity and precipitation amount, is important in controlling the intra-seasonal tree-ring isotopic cycle, and we speculate that the same controls also operate on interannual and longer time scales. If so, multi-century δ 18 O records with intra-seasonal resolution may enable us to infer long-term variations in the incursion of the Indian Monsoon onto the Qinghai–Tibetan Plateau. [ABSTRACT FROM AUTHOR]

To reveal the influence of current warming on tree growth and δ18O in a sensitive high-latitude region that is undergoing rapid climate change, we examined tree width and the earlywood and latewood δ18O at two sites with a 400-m elevation difference in the Sygera Mountains of the southeastern Tibetan Plateau. The study period was from 1950 to 2011. The mean tree-ring index at the low site was higher than that at the high site during the study period. The climatic responses of earlywood and latewood δ18O at both sites were similar. Earlywood δ18O was mainly influenced by the June to August temperature and total cloud cover, whereas latewood δ18O was mainly controlled by relative humidity from July to August. Spatial correlations with CRU TS 3.1 regional data suggest that our δ18O chronologies can represent climatic changes over large regions. The high offset between earlywood δ18O at the two sites (2.3‰ higher at the low site) was mainly influenced by the high temperature lapse rate as a function of altitude during the earlywood growing season. Furthermore, meltwater with lower δ18O values might have affected earlywood δ18O at the high site, and thereby increased the earlywood δ18O offset between two sites. The low latewood δ18O offset between the two sites (0.4‰ higher at the low site) was not significant, but appears to have been primarily influenced by the low precipitation δ18O lapse rate as a function of altitude during the latewood growing season. Earlywood δ18O of Smith fir suitable for reconstructing past temperatures and latewood δ18O suitable for reconstructing past relative humidity on the southeastern Tibetan Plateau were identified. [ABSTRACT FROM AUTHOR]

The hydroclimate of southwestern China has experienced pronounced fluctuations over the past few decades. In this study, the total cloud cover variability of southwestern China during May–October for the past 276 years was reconstructed based on the composite tree-ring δ18O chronology. The record spans the common interval from 1734 to 2009 CE. Moisture-related factors, such as relative humidity, the precipitation, and cloud cover over the region, were the climatic factors controlling tree-ring δ18O. The reconstructed cloud cover exhibited a decreasing trend since 1900, which was linked to the weakening of the Indian summer monsoon. However, the relationship between cloud cover and the monsoon system was temporally unstable, which may be due to El Niño-southern oscillation and the Indian Ocean dipole. Furthermore, the sea surface temperature (SST) over the Indian and East Pacific oceans influenced the delivery of moisture over the study area; however, the influence of SST on the different oceanic regions varied between different periods. During the low-cloud-cover period, the link between SST and regional cloud cover weakened, and local circulation became the driving factor. Additionally, local circulation may disrupt the influence of monsoons on the hydroclimate in southwestern China, which was supported by the backward trajectory results. [Display omitted] • Reconstructed cloud cover variability based on tree-ring δ18O chronology in SW China. • The temporal relationship between the ISM and regional cloud cover varied. • The unstable relationship may be due to the interactions of ENSO and IOD. • The SST in the Indian and Pacific oceans interfere with the influence of the ISM. [ABSTRACT FROM AUTHOR]

Abstract: We developed a new tree-ring cellulose δ18O chronology for the southeastern Tibetan Plateau from Balfour spruce (Picea likiangensis var. balfouriana [Rehd. et Wils.]) that covered the period from 1600 to 2008, and compared the results with a previous study to explore climatic variations in the Nyingchi-Bomi area. Our tree-ring δ18O chronology correlated significantly with the previous study (Shi et al., 2012; Climate of the Past 8, 205–213) during the common period from 1781 to 2005, and provided new insights into long-term regional hydroclimatic variations. Besides the significant positive correlations between tree-ring δ18O and the temperature and sunshine duration during the growing season, tree-ring δ18O was strongly negatively correlated with regional cloud cover, relative humidity, and precipitation in July and August. The correlations with cloud cover data were stronger than in previous research, but the correlations with precipitation and relative humidity in July and August were weaker. When Indian summer monsoon conditions prevail, regional hydroclimate variations (and especially cloud cover) have the dominant influence on tree-ring δ18O in the study area. Based on the regional data, δ18O in tree rings can be an effective proxy to infer the temporal variations in regional hydroclimatic conditions and the strength of the Indian Summer Monsoon. Our results reveal that the Indian Summer Monsoon weakened from 1600 to 1650, followed by continuous strengthening until 1740 and a slight weakening from 1740 to present. The temporal variations in the cellulose δ18O chronology generally corresponded well to the δ18O and glacier snow accumulation records found in ice cores from the middle Himalaya. [Copyright &y& Elsevier]

The site of Zhengzhou Shang City (ca. 1509-1315 cal. BC) was the capital of the early Shang Dynasty in China. Archaeological excavations have unearthed a ditch containing approximately one hundred unusual dead human skulls in the rammed-earth foundations of the palace area. The identity and origin of the skulls have long been disputed. In this work, strontium, carbon and nitrogen stable isotope analyses were carried out on 11 human skulls and 1 tooth from the ditch, as well as on 11 human bones, 11 human teeth from the ordinary tombs and 10 pig teeth from the Zhengzhou Shang City site. We determined that, in Zhengzhou Shang City, the local strontium isotope ratio ranges from 0.711606 to 0.711884, and ordinary inhabitants consumed mainly C4 plants supplemented by C3 plants. Moreover, humans buried in the ditch have 87Sr/86Sr values from 0.711335 to 0.711741 and consumed only C4 plants. Combining the isotopic data with the archaeological and cultural context, it is concluded that the unusual human skulls in the ditch are most likely those of prisoners of war captured by the central forces conquering the Xiaomintun area of Anyang in the early Shang Dynasty. The results provide valuable insight into the history of violence and military warfare in the early Chinese dynasty. [ABSTRACT FROM AUTHOR]

Zinc metal featuring intrinsic safety, low cost, and high volumetric capacity is an attractive anode material in aqueous batteries. However, the practical application of Zinc-based batteries is seriously impeded by the uneven stripping/plating of zinc ions as well as low coulombic efficiency due to the side reaction at the electrode-electrolyte interface. Herein, polyacrylamide interphase is constructed via in-situ polymerization of acrylamide additive, which can constrain freely lateral diffusion of zinc ions and suppress parasitic reactions, endowing zinc anode with homogeneous nucleation and high coulombic efficiency. With this method, a stable metal-electrolyte interface can be formed and a prolonged lifespan of more than 680 h at 1 mA cm−2 for 1 mA h cm−2 can be obtained. [ABSTRACT FROM AUTHOR]

Climate warming-induced changes in the hydrological habitat for the alpine treeline can significantly impact tree growth and community dynamics. However, composite indicators that capture typical alpine species' responses to temperature and precipitation are lacking. This study investigates the use of the δ 2H values of lignin methoxy groups (δ 2H LM) from the dominant deciduous conifer tree (Larch chinensis) and evergreen broadleaf shrub (Rhododendron purdomii) in the upper treeline of the Qinling Mountains from 1960 to 2018 as potential hydroclimatic indicators. The δ 2H LM values of the R. purdomii shrubs were enriched by 23.3‰ in 2H compared with those of the L. chinensis trees. However, the multispecies δ 2H LM composite significantly reflected the temperature and precipitation during the growing season (May to September). Rapid warming and drying after the 1990s increased the interspecies consistency of δ 2H LM variability, accompanied by a decreasing enrichment trend. The weighted self-calibrated Palmer Drought Severity Index showed a similar variation tendency. Similar isotopic patterns were detected for the δ 2H values of precipitation (δ 2H Pre) and the composite δ 2H LM values. The latest empirical relationship mode can effectively verify the reconstructed δ 2H Pre values using the δ 2H LM composite from the alpine treeline. These results indicate that the cross-species composite tree-ring δ 2H LM can accurately indicate the alpine hydroclimatic conditions during the growing season, including the warming and drying periods. • Growing season temperature and precipitation correlate with tree-ring δ 2H LM in typical treeline species. • Reconstruction of precipitation δ 2H based on δ 2H LM across species significantly agrees with the empirical model. • Composite tree-ring δ 2H LM accurately indicates alpine hydroclimatic conditions. [ABSTRACT FROM AUTHOR]

In arid and semiarid regions, riparian forests are crucial for maintaining ecological biodiversity and sustainability, and supporting social and economic development. For the typical arid and semiarid ecosystem, streamflow variability is thought to be the dominant factor influencing the vulnerability and evolution of the riparian forests, which often leads to the neglect of other potentially important factors such as nutrient availability and transport. Here, we measured annual stable nitrogen isotopes (δ15N) and nitrogen concentrations (N%) in the tree rings of Populus euphratica Oliv. (Euphrates poplar) over a 90 year period (1920–2012), collected from the lower researches of the inland Heihe River, northwestern China. Coupling with our previous dual-isotope (δ13C and δ18O) chronologies and estimated intrinsic water-use efficiency (iWUE), we examined the linkages between tree-ring δ15N and δ18O, iWUE, streamflow, and then explored the contributions of each to tree growth during the study period. Our results show that after 1975, a statistically significant correlation between tree-ring δ15N and river streamflow appears, indicating the river as a potential carrier of nitrogen from the upper and middle reaches to the lower research trees. In addition, the linkage between tree-ring δ15N and iWUE suggests substantial influence of carbon and nitrogen together on photosynthesis and transpiration of trees, although this connection become decoupled since AD 1986. The commonality analysis revealed that the nitrogen impacts indicated by tree-ring δ15N on tree growth cannot be ignored when evaluating riparian forest development. The fertilization effects caused by rising CO 2 concentration complicate the nitrogen constraints on tree growth during the later part of the past century. Our results have potentially broad implications for identifying the limited factors for dryland forest ecosystems that are susceptible to natural water resource variations and human activities. • Tree-ring δ15N increased with a rate of 0.4‰ per decade but nitrogen concentration remained stable during 1930–2008. • Tree-ring δ15N and streamflow both showed rising trends, but they only significantly correlated over the period of 1975–1994. • The carbon and nitrogen cycling of riparian trees was associated but decoupled after 1986. • The δ15N and iWUE regulated Euphrates poplar tree growth together, but they have different dominant periods. [ABSTRACT FROM AUTHOR]

Despite its cost-effectiveness and intrinsic safety, the aqueous zinc-iodine battery is still struggling with the rapid performance degradation arising from the uneven deposition of the zinc anode and the dissolution of the iodine cathode. An effective solution of addressing the above issues simultaneously is urgently needed. Here we propose a strategy of using one porous carbon to modify the zinc anode and immobilize the iodine active materials. Zinc citrate-derived porous carbon is selected as a study model. The conductive porous carbon can not only greatly reduce the zinc nucleation barrier, and guide a uniform deposition of zinc ions, but also notably suppress the dissolution of iodine species and enhance the reaction kinetics. As a consequence, the optimized zinc-iodine battery exhibits capacity retention of 88.1% after 3000 cycles at 12C, finishing a cycle within 5 min. In this work, we proposed a strategy of using one multifunctional porous carbon to modify the zinc anode and immobilize the iodine active materials simultaneously. [Display omitted] [ABSTRACT FROM AUTHOR]

• We applied a model to explore the response of spruce and pine growth to drought. • Both species were sensitive to early-growing-season soil moisture availability. • The mean contribution of soil moisture were above 80% for both tree species. • The two tree species displayed similar patterns of resilience to drought. Understanding the mechanisms for how tree growth responds to drought is important for forest conservation and management in semi-arid regions, particularly under ongoing climate change. However, most previous studies have been relied on linear statistical analysis, unsupported by insights into tree physiological processes. In this study, we applied process-based Vaganov–Shashkin (VS) model to investigate the stem radial growth response and resilience of Qinghai spruce (Picea crassifolia) and Chinese pine (Pinus tabuliformis) to intense drought in semi-arid region of China from 1960 to 2013. Correlation analysis indicated that soil moisture availability in the early growing season (May to July) significantly limit stem growth for both tree species, but Chinese pine was affected more strongly by drought legacies. The model results validated our statistical modeling results, and quantified the effects of temperature and soil moisture on the intra-seasonal variation of the relative stem radial growth rate. The influence of soil moisture on the relative stem radial growth rate during the early growing season was significantly higher for positive pointer years (years with greater than mean growth) than for negative pointer years (years with less than mean growth) for both tree species. Interestingly, the two species displayed similar patterns of growth resilience in response to drought. Based on our successful application of the VS model, our results provide important insights into the two main tree species in the semi-arid Helan Mountains, and offer a new perspective on tree growth processes and their varying responses and resilience to drought. [ABSTRACT FROM AUTHOR]

Background: Microcirculatory dysfunction is associated with increased morbidity and mortality in cardiac surgery patients. This study aimed to investigate the association between preoperative retinal microcirculation evaluated using optical coherence tomography angiography (OCTA) and perioperative outcomes in patients with congenital heart disease (CHD). Methods: This prospective, observational study was performed from May 2017 to January 2021. OCTA was used to automatically quantify the vessel density (VD) of the superficial capillary plexus, deep capillary plexus (DCP), and radial peripapillary capillary (RPC) preoperatively. The primary outcome was excessive postoperative bleeding, defined as bleeding volume > 75th percentile for 24-hour postoperative chest tube output. The secondary outcome was composite adverse outcomes, including one or more operative mortalities, early postoperative complications, and prolonged length of stay. The association between retinal VD and outcomes was assessed using Poisson regression. Results: In total, 173 CHD patients who underwent cardiac surgery were included (mean age, 26 years). Among them, 43 (24.9%) and 46 (26.6%) developed excessive postoperative bleeding and composite adverse outcomes, respectively. A lower VD of DCP (odds ratio [OR], 1.24; 95% confidence interval [CI], 1.08–1.43; P = 0.003) was independently associated with excessive postoperative bleeding, and a lower VD of RPC (OR, 1.97; 95% CI, 1.08–3.57; P = 0.027), and DCP (OR, 2.17; 95% CI, 1.08–4.37; P = 0.029) were independently associated with the postoperative composite adverse outcomes. Conclusion: Preoperative retinal hypoperfusion was independently associated with an increased risk of perioperative adverse outcomes in patients with CHD, suggesting that retinal microcirculation evaluation could provide valuable information about the outcomes of cardiac surgery, thereby aiding physicians in tailoring individualized treatment. [ABSTRACT FROM AUTHOR]

This study introduces a versatile electrolyte additive, nicotinamide, for zinc anodes, aiming to facilitate uniform deposition and suppress water-induced side reactions. The molecular structure, consisting of a pyridine ring and an amide function group, endows NTA molecules with the ability to regulate electrolyte pH, enhance nucleation overpotential, and constrain 2D diffusion of Zn2+. As a result, the full battery configuration with this additive achieved an impressive lifespan of over 10 000 cycles. [ABSTRACT FROM AUTHOR]

Climate warming may induce growth decline in warm-temperate areas subjected to seasonal soil moisture deficit, whereas increasing atmospheric CO2 concentration (Ca) is expected to enhance tree growth. An accurate understanding of tree growth and physiological processes responding to climate warming and increasing Ca is critical. Here, we analyzed tree-ring stable carbon isotope and wood anatomical traits of Pinus tabuliformis from Qinling Mountains in China to understand how lumen diameter (LD) determining potential hydraulic conductivity and cell-wall thickness (CWT) determining carbon storage responded to climate and Ca. The effects of climate and Ca on intrinsic water-use efficiency (iWUE) were isolated, and iWUE values due to only-climate (iWUEClim) and only-CO2 effects (iWUECO2) were obtained. During a low-iWUE period, the influences of climate on earlywood (EW) LD and latewood (LW) CWT prevailed. During a high-iWUE period, CO2 fertilization promoted cell enlargement and carbon storage but this was counteracted by a negative influence of climate warming. The limiting direct effects of iWUEClim and indirect effects of climate on EW LD were greater than on LW CWT. P. tabuliformis in temperate forests will face a decline of growth and carbon fixation, but will produce embolism-resistant tracheids with narrow lumen responding to future hotter droughts. [ABSTRACT FROM AUTHOR]

In biomedical data mining, the gene dimension is often much larger than the sample size. To solve this problem, we need to use a feature selection algorithm to select feature gene subsets with a strong correlation with phenotype to ensure the accuracy of subsequent analysis. This paper presents a new three-stage hybrid feature gene selection method, that combines a variance filter, extremely randomized tree, and whale optimization algorithm. First, a variance filter is used to reduce the dimension of the feature gene space, and an extremely randomized tree is used to further reduce the feature gene set. Finally, the whale optimization algorithm is used to select the optimal feature gene subset. We evaluate the proposed method with three different classifiers in seven published gene expression profile datasets and compare it with other advanced feature selection algorithms. The results show that the proposed method has significant advantages in a variety of evaluation indicators. [ABSTRACT FROM AUTHOR]

RNA modification is a key regulatory mechanism involved in tumorigenesis, tumor progression, and the immune response. However, the potential role of RNA modification "writer" genes in the immune microenvironment of gliomas and their effect on the response to immunotherapy remains unclear. The purpose of this study was to evaluate the role of RNA modification "writer" gene in the prognosis and immunotherapy response of low-grade glioma (LGG). The consensus non-negative matrix factorization (CNMF) method was used to identify different RNA modification subtypes. We used a novel eigengene screening method, the variable neighborhood learning Harris Hawks optimizer (VNLHHO), to screen for eigengenes among the RNA modification subtypes. We constructed a principal components analysis score(PCA_score)-based prognostic prediction model and validated it using an independent cohort. We also analyzed the association between PCA_score and the immune and molecular features of LGG. The results suggested that LGG can be divided into two different RNA modification-based subtypes with distinct prognostic and molecular features. High PCA_score was significantly associated with a poor prognosis in LGG and was an independent prognostic factor. A nomogram containing PCA_score and clinical features was constructed, and it showed a significant predictive value. PCA_score was negatively correlated with tumor purity and the abundance of CD4+ T cells in LGG patients. LGG patients with high PCA_score had lower Tumor Immune Dysfunction and Exclusion scores and showed an immunotherapy response. In conclusion, we report a novel RNA modification-based prognostic model for LGG that lays the foundation for evaluating LGG prognosis and developing more effective therapeutic strategies for these tumors. [ABSTRACT FROM AUTHOR]

Abundant evidence has indicated that the prognosis of cutaneous melanoma (CM) patients is highly complicated by the tumour immune microenvironment. We retrieved the clinical data and gene expression data of CM patients in The Cancer Genome Atlas (TCGA) database for modelling and validation analysis. Based on single-sample gene set enrichment analysis (ssGSEA) and consensus clustering analysis, CM patients were classified into three immune level groups, and the differences in the tumour immune microenvironment and clinical characteristics were evaluated. Seven immune-related CM prognostic molecules, including three mRNAs (SUCO, BTN3A1 and TBC1D2), three lncRNAs (HLA-DQB1-AS1, C9orf139 and C22orf34) and one miRNA (hsa-miR-17-5p), were screened by differential expression analysis, ceRNA network analysis, LASSO Cox regression analysis and univariate Cox regression analysis. Their biological functions were mainly concentrated in the phospholipid metabolic process, transcription regulator complex, protein serine/threonine kinase activity and MAPK signalling pathway. We established a novel prognostic model for CM integrating clinical variables and immune molecules that showed promising predictive performance demonstrated by receiver operating characteristic curves (AUC ≥ 0.74), providing a scientific basis for predicting the prognosis and improving the clinical outcomes of CM patients. [ABSTRACT FROM AUTHOR]

Abundant evidence has indicated that the prognosis of cutaneous melanoma (CM) patients is highly complicated by the tumour immune microenvironment. We retrieved the clinical data and gene expression data of CM patients in The Cancer Genome Atlas (TCGA) database for modelling and validation analysis. Based on single-sample gene set enrichment analysis (ssGSEA) and consensus clustering analysis, CM patients were classified into three immune level groups, and the differences in the tumour immune microenvironment and clinical characteristics were evaluated. Seven immune-related CM prognostic molecules, including three mRNAs (SUCO, BTN3A1 and TBC1D2), three lncRNAs (HLA-DQB1-AS1, C9orf139 and C22orf34) and one miRNA (hsa-miR-17-5p), were screened by differential expression analysis, ceRNA network analysis, LASSO Cox regression analysis and univariate Cox regression analysis. Their biological functions were mainly concentrated in the phospholipid metabolic process, transcription regulator complex, protein serine/threonine kinase activity and MAPK signalling pathway. We established a novel prognostic model for CM integrating clinical variables and immune molecules that showed promising predictive performance demonstrated by receiver operating characteristic curves (AUC ≥ 0.74), providing a scientific basis for predicting the prognosis and improving the clinical outcomes of CM patients. [ABSTRACT FROM AUTHOR]

In patients with gliomas, depression is a common complication that may cause severe psychological barriers and deteriorate the patient's quality of life (QoL). Currently, the Hospital Anxiety and Depression Scale (HADS) is the most commonly used tool to diagnose depression in patients with gliomas. Female sex, unmarried status, low education level, high tumor grade, and a history of mental illness may increase the risks of depression and depressive symptoms in patients with gliomas. The QoL of patients with gliomas can be directly reduced by depression. Therefore, the evaluation and intervention of mood disorders could improve the overall QoL of patients with gliomas. Antidepressant use has become a treatment strategy for patients with gliomas and comorbid depression. This narrative review summarizes the current issues related to depression in patients with gliomas, including the prevalence, risk factors, and diagnostic criteria of depression as well as changes in QoL caused by comorbid depression and antidepressant use. The purpose of this review is to guide clinicians to assess the psychological status of patients with gliomas and to provide clinicians and oncologists with a new treatment strategy to improve the prognosis of such patients. [ABSTRACT FROM AUTHOR]

Farmland mulching can maintain soil nutrients, which plays a positive role in agricultural planting in the arid area. However, the composition of the soil microbial community and the C cycle involved is unclear under farmland mulching. Based on the Changwu Agro‐Ecological Experiment Station, this study set up a long‐term positioning experiment to explore the effect on soil bacterial community structure and C metabolism capacity. In this study, we include five treatments: control uncovered (CK), plastic film mulching (PF), high amount of straw mulching carried out in July, August, and September every year (St90), low amount of straw mulch throughout the growth period (S45), and high amount of straw cover throughout the growth period (S90). We combined Illumina MiSeq sequencing and Biolog‐ECO technology to analyze the functional characterization of soil bacterial community composition in terms of C source metabolism. The results indicated that the soil bacteria showed a high degree of epistatic clustering, and the operational taxonomic unit numbers of soil bacteria decrease as St90, S45, PF, CK, and S90. Redundancy analysis showed that soil available P, NH4+–N, soil moisture content were the main environmental factors affecting bacterial community composition. Proteobacteria, Acidobacteria, and Actinobacteria are the main dominant flora in this area. Soil bacterial C metabolism was highest under PF treatment. Structural equation modeling (SEM) shows that surface cover has direct and indirect effects on bacterial C metabolism capacity and diversity through soil physicochemical properties. Reasonable mulching methods have a positive effect on the sustainable development of agro‐ecosystems in arid areas. Core Ideas: Straw mulching significantly increased soil organic C content.The available phosphorus, NH4+–N, moisture content were the main environmental factors affecting bacterial community.The C source metabolism of bacteria was the strongest under plastic film mulch. [ABSTRACT FROM AUTHOR]

HCoV-HKU1 is a β -coronavirus with low pathogenicity, which usually leads to respiratory diseases. At present, a controversial issue is that whether the receptor binding site (RBS) of HCoV-HKU1 is located in the N-terminal domain (NTD) or the C-terminal domain (CTD) in the HCoV-HKU1 S protein. To address this issue, we used molecular docking technology to dock the NTD and CTD with 9-oxoacetylated sialic acid (9-O-Ac-Sia), respectively, with the results showing that the RBS of HCoV-HKU1 is located in the NTD (amino acid residues 80–95, 25–32). Our findings clarified the structural basis and molecular mechanism of the HCoV-HKU1 infection, providing important information for the development of therapeutic antibody drugs and the design of vaccines. [ABSTRACT FROM AUTHOR]

Gene expression profiling has played a significant role in the identification and classification of tumor molecules. In gene expression data, only a few feature genes are closely related to tumors. It is a challenging task to select highly discriminative feature genes, and existing methods fail to deal with this problem efficiently. This article proposes a novel metaheuristic approach for gene feature extraction, called variable neighborhood learning Harris Hawks optimizer (VNLHHO). First, the F -score is used for a primary selection of the genes in gene expression data to narrow down the selection range of the feature genes. Subsequently, a variable neighborhood learning strategy is constructed to balance the global exploration and local exploitation of the Harris Hawks optimization. Finally, mutation operations are employed to increase the diversity of the population, so as to prevent the algorithm from falling into a local optimum. In addition, a novel activation function is used to convert the continuous solution of the VNLHHO into binary values, and a naive Bayesian classifier is utilized as a fitness function to select feature genes that can help classify biological tissues of binary and multi-class cancers. An experiment is conducted on gene expression profile data of eight types of tumors. The results show that the classification accuracy of the VNLHHO is greater than 96.128% for tumors in the colon, nervous system and lungs and 100% for the rest. We compare seven other algorithms and demonstrate the superiority of the VNLHHO in terms of the classification accuracy, fitness value and AUC value in feature selection for gene expression data. [ABSTRACT FROM AUTHOR]

Background: At present, the most effective and mature treatment after ACL injury and tear is ACL reconstruction, but the rehabilitation process after ACL reconstruction that is very long, so it is very important to find early MRI positive findings of knee instability.Methods: We retrospectively collected the clinical and imaging data of 70 patients who underwent ACL reconstruction from January 2016 to December 2019; Based on clinical criteria, the patients were divided into a stable group (n = 57) and an unstable group (n = 13); We measured the MRI imaging evaluation indexes, including the position of the bone tunnel, graft status, and the anatomical factors; Statistical methods were used to compare the differences of imaging evaluation indexes between the two groups; The prediction equation was constructed and ROC curve was used to compare the prediction efficiency of independent prediction factors and prediction equation.Results: There were significant differences in the abnormal position of tibial tunnel entrance, percentage of the position of tibial tunnel entrance, position of tibial tunnel exit, lateral tibial posterior slope (LTPS), width of intercondylar notch between stable knee joint group and unstable knee joint group after ACL reconstruction (P < 0.05); The position of tibial tunnel exits and the lateral tibial posterior slope (LTPS) and the sagittal obliquity of the graft were independent predictors among surgical factors and self-anatomical factors (P < 0.05); The prediction equation of postoperative knee stability was established: Logit(P) = -1.067-0.231*position of tibial tunnel exit + 0.509*lateral tibial posterior slope (LTPS)-2.105*sagittal obliquity of the graft; The prediction equation predicted that the AUC of knee instability was 0.915, the sensitivity was 84.6%, and the specificity was 91.2%.Conclusions: We found that abnormalities of the position of the exit of the bone tunnel, lateral tibial posterior slope (LTPS) and sagittal obliquity of the graft were the early MRI positive findings of knee instability after ACL reconstruction. It is helpful for clinicians to predict the stability of knee joint after ACL reconstruction. [ABSTRACT FROM AUTHOR]

Rising atmospheric carbon dioxide (CO2) may enhance tree growth and mitigate drought impacts through CO2 fertilization. However, multiple studies globally have found that rising CO2 has not translated into greater tree growth despite increases in intrinsic water-use efficiency (iWUE). The underlying mechanism discriminating between these two general responses to CO2 fertilization remains unclear. We used two species with contrasting stomatal regulation, the relatively anisohydric Qilian juniper (Sabina przewalskii) and the relatively isohydric Qinghai spruce (Picea crassifolia), to investigate the long-term tree growth and iWUE responses to climate change and elevated CO2 using tree ring widths and the associated cellulose stable carbon isotope ratios (δ13C). We observed a contrasting growth trend of juniper and spruce with juniper growth increasing while the spruce growth declined. The iWUE of both species increased significantly and with similar amplitude throughout the trees' lifespan, though the relatively anisohydric juniper had higher iWUE than the relatively isohydric spruce throughout the period. Additionally, with rising CO2, the anisohydric juniper became less sensitive to drought, while the relatively isohydric spruce became more sensitive to drought. We hypothesized that rising CO2 benefits relatively anisohydric species more than relatively isohydric species due to greater opportunity to acquire carbon through photosynthesis despite warming and droughts. Our findings suggest the CO2 fertilization effect depends on the isohydric degree, which could be considered in future terrestrial ecosystem models. [ABSTRACT FROM AUTHOR]

• Accelerated tree growth coincided with increased water-use efficiency in mature Qinghai spruce. • Nitrogen availability positively affected tree growth from 1920 to 2000. • Tree-ring δ15N and C/N values have decreased synchronously since 1965 onwards. • Tree growth enhancement in 2003–2019 was driven by CO 2 fertilization, not by nitrogen availability. Terrestrial vegetation growth is stimulated by rising atmospheric CO 2 concentration, a warmer climate, and increased soil nutrient availability. However, as plants age, progressive nutrient limitation is known to occur, especially in mature forests where soil nitrogen is deficient. Yet the long-term growth response of mature trees to rising CO 2 accompanied by changing climate and nitrogen availability in semi-arid mountain regions is unclear. Here we used tree-ring widths and stable carbon (δ13C) and nitrogen (δ15N) isotopes to investigate the drivers of radial growth of mature Qinghai spruce (Picea crassifolia) in the central Qilian Mountains, northwest China, from 1840 through 2019. Tree growth benefited from improved nitrogen availability, chiefly via changes in bioavailable nitrogen pools modified by a favorable climate during 1930–1964. Enhanced intrinsic water-use efficiency (iWUE), driven by reduced stomatal conductance (g s) related to water deficit, lead to radial growth declines in 1985–2002. Recent acceleration of tree growth was largely attributed to a CO 2 fertilization effect through enhanced iWUE during 2003–2019. Nitrogen availability was positively related to tree growth from the 1920s onward until greater CO 2 fertilization ensued from 2000 onward. Hence, the negative effects of low nitrogen availability on growth could be mitigated or reversed by a high atmospheric CO 2 concentration and warmer climate conditions. Our results suggest that mature spruce forests still harbor potential to increase ecosystem-level carbon sequestration and thereby partially mitigate climate warming. Such a nature-based solution in drought-prone forests would be achieved under warmer-wetter climate conditions in northwest China. [ABSTRACT FROM AUTHOR]

• Segregated ZnO-In 2 O 3 porous nanosheets are synthesized facilely via one-pot solvothermal method. • The doped Indium stems the porous nanosheets stacking, inducing lots of heterojunctions. • The sensor exhibits superior ethanol sensing behaviors under natural humidity for a long period. • After aging for 10 months, the device shows celerity response to simulated drunken subjects. • This study meets the challenge of repeatably and reliably superior ethanol sensing performance in real world. ZnO nanosheets exhibit notably interesting gas sensing performances due to their great carrier transport and high special surface area. However, not only the 2D nanosheets tend to stack suppressing the surface area, but also the pristine ZnO cannot show desired ethanol sensing properties. Herein, segregated ZnO-In 2 O 3 porous nanosheets are synthesized facilely via one-pot solvothermal method. The Indium doping stems the porous nanosheets stacking, as well as induces lots of heterojunctions. Due to the specific porous structure for high gas accessibility, thickness less than double Debye length, abundant reaction sites and heterojunctions, the segregated ZnO-In 2 O 3 nanosheets exhibit remarkable ethanol sensing performance (LOD of 100 ppb, response/recovery time of 3/8 s, and great repeatability and selectivity under natural humidity for a long period). This study provides a prospect for practical applications of ZnO-In 2 O 3 ethanol sensors. [ABSTRACT FROM AUTHOR]

Importance A high prevalence of retinal abnormalities have been reported in congenital heart disease (CHD), but quantitative analysis of retinal vasculature is scarce. Optical coherence tomography angiography (OCTA) is a noninvasive method to quantitatively assess the retinal microvasculature. Background: To investigate the retinal microvasculature changes in CHD patients by using OCTA. Design Cross‐sectional study. Participants: A total of 158 participants including 57 cyanotic CHD (CCHD) patients, 60 acyanotic CHD (ACHD) patients and 41 control subjects were included. Methods: All participants underwent a comprehensive ophthalmologic examination, including refraction measurement, intraocular pressure measurement and OCTA. Main Outcome Measures: Vessel density (VD) was measured within the radial peripapillary capillary (RPC), superficial capillary plexus (SCP) and deep capillary plexus (DCP) of the macula. Results: CCHD patients had significantly lower VD in the RPC, SCP and DCP (all P <.01) compared to control subjects, and significantly lower VD in the RPC and DCP (both P <.05) compared to ACHD patients. Besides, among the CHD group, VD in the RPC was positively correlated with oxygen saturation (whole image, ρ = 0.45; peripapillary, ρ = 0.48) and negatively correlated with haematocrit (whole image, ρ = 0.55; peripapillary, ρ = 0.55) (all P <.001). Conclusions and Relevance: Retinal VD might be a surrogate to reflect the effect of chronic systemic hypoxemia in CHD patients. OCTA could be a convenient and noninvasive tool to evaluate the retinal structure and function in CHD patients. [ABSTRACT FROM AUTHOR]

Aim. To analyze the levels of B-cell-produced antibodies in the vitreous humor of patients with or without diabetic retinopathy (DR) both qualitatively and quantitatively. Methods. A total of 52 type 2 diabetes mellitus (T2DM) with DR patients and 52 control subjects without diabetes mellitus or inflammatory diseases were included in this prospective study. The levels of immunoglobulin (Ig)A, IgM, and IgG subtypes were measured using a magnetic color-bead-based multiplex assay. Results. The concentrations of IgA, IgM, and total antibodies in the DR group were significantly higher than those in the control group (all p < 0.001), but there was no significant difference in the 4 IgG subtypes between the two groups after Bonferroni correction. Pearson's correlation analysis revealed low negative correlations between levels of antibodies (IgA, IgM) and estimated glomerular filtration rate (eGFR, r = − 0.443 , r = − 0.377 , respectively, both p < 0.05). Furthermore, multiple linear regression analysis yielded three equations to predict the concentrations of IgA, IgM, and total antibodies in the vitreous humor according to eGFR and other clinical variables (r = 0.542 , r = 0.461 , and r = 0.312 , respectively, all p < 0.05). Conclusion. Increased levels of IgA, IgM, and total antibodies produced by B cells were observed in the vitreous humor of T2DM patients with DR. There were low negative correlations between levels of antibodies (IgA, IgM) and eGFR. [ABSTRACT FROM AUTHOR]

Purpose. To evaluate the impact of restoration of foveal bulge (FB) in optical coherence tomography (OCT) images on visual acuity after resolution of diabetic macular edema with coexisting serous retinal detachment (SRD-DME). Methods. A total of 52 eyes with resolved SRD-DME and an intact ellipsoid zone at the central fovea were included. All eyes underwent best-corrected visual acuity (BCVA) examination and OCT scanning at baseline and follow-up visits (1, 3, and 6 months). The eyes were divided into two groups according to the presence of FB at 6 months. BCVA, central foveal thickness (CFT), height of SRD (SRDH), outer nuclear layer (ONL) thickness, photoreceptor inner segment (PIS), and outer segment (POS) length were compared between the two groups. Results. A FB was found in 25 of 52 (48%) eyes at 6 months. The FB (+) group had lower SRDH at baseline, and better BCVA, longer POS length at 6 months (all P < 0.05). There was no significant difference in the CFT, ONL thickness, and PIS length at 6 months between the two groups (all P > 0.05). More eyes in the FB (+) group had complete SRD resolution at 1 month (P = 0.009) and 3 months (P = 0.012). Eyes with complete SRD resolution at 1 month (P = 0.009) or 3 months (P = 0.012) were more likely to have a FB at 6 months. Conclusions. The Presence of the FB is associated with better BCVA after resolution of SRD-DME. Eyes with lower baseline SRDH or faster SRD resolution are more likely to have a FB at 6 months. [ABSTRACT FROM AUTHOR]

Tree-ring δ13C and δ18O of dominant Dahurian larch and Mongolia pine in the permafrost region of the northern Great Higgnan Mountains, China were used to elucidate species-specific ecophysiological responses to warming temperatures and increasing CO2 over the past century. Larch and pine stable carbon discrimination (Δ13C) 13C and δ18O in tree rings both showed synchronous changes during the investigated period (1901–2010), but with species-specific isotopic responses to atmospheric enriched CO2 and warming. Tree-ring Δ13C and δ18O were controlled by both maximum temperature and moisture conditions (precipitation, relative humidity and vapor pressure deficit), but with different growth periods (Δ13C in June–July and δ18O in July–August, respectively). In addition, stable isotopes of larch showed relatively greater sensitivity to moisture deficits than pine. Climatic conditions from 1920 to 1960 strongly and coherently regulated tree-ring Δ13C and δ18O through stomatal conductance. However, climatic-sensitivities of tree-ring Δ13C and δ18O recently diverged, implying substantial adjustments of stomatal conductance, photosynthetic rate and altered water sources over recent decades, which reveal the varied impacts of each factor on tree-ring Δ13C and δ18O over time. Based on expected changes in leaf gas-exchange, we isolated the impacts of atmospheric CO2 and climate change on intrinsic water-use efficiency (iWUE) over the past century. Higher intracellular CO2 in pine than larch from 1960 onwards suggests this species may be more resilient to severe droughts in the future. Our data also illustrated no weakening of the iWUE response to increasing CO2 in trees from this permafrost region. The overall pattern of CO2 enrichment and climate impacts on iWUE of pine and larch were similar, but warming increased iWUE of larch to a greater extent than that of pine over recent two decades. Taken together, our findings highlight the importance of considering how leaf gas-exchange responses to atmospheric CO2 concentration influence species-specific responses to climate and the alteration of the hydrological environment in forests growing in regions historically dominated by permafrost that will be changing rapidly in response to future warming and increased CO2. [ABSTRACT FROM AUTHOR]

Drought occurrence and duration in central Asia are of important socioeconomic, ecological, and geophysical significance and have received increasing research attention in recent years. Understanding long-term drought trends and their driving forces require reliable records of past drought variability with broad spatial representativeness. Here, we compiled four tree-ring δ18O records from eastern central Asia (ECA) and composited them into a drought-sensitive proxy to explore regional ECA moisture variations over the past 301 years (1710-2010 CE). A robust regional standardized precipitation-evapotranspiration index (SPEI) reconstruction was established based on the tree-ring cellulose δ18O fractionation mechanism and statistically significant proxy-climate relationships. We identified prominent droughts in 1710-1770, 1810-1830, and the beginning of the twenty-first century, and a regime shift to a persistently wet period from the 1880s to 2000. Our reconstruction reveals the impact of drought and pluvial patterns on the decline of Zhungar Empire, and on historical agricultural and socio-economical activities, including increased migration into ECA during the 1770-1800 pluvial. Our findings also suggest that wet conditions in the twentieth century in ECA were related to a strengthening of the westerly circulation and thus shed light on large-scale atmospheric circulation dynamics in central Asia. [ABSTRACT FROM AUTHOR]

To quantitatively investigate alterations of retinal microcirculation in patients with non-obstructive coronary artery disease (NOCAD) using optical coherence tomography angiography (OCTA), and to identify the ability of retinal microcirculation parameters in differentiating coronary artery disease (CAD) subtypes. All participants with angina pectoris underwent coronary computed tomography angiography. Patients with lumen diameter reduction of 20–50 % in all major coronary arteries were defined as NOCAD, while patients with at least one major coronary artery lumen diameter reduction ≥ 50 % were recruited as obstructive coronary artery disease (OCAD). Participants without a history of ophthalmic or systemic vascular disease were recruited as healthy controls. Retinal neural-vasculature was measured quantitatively by OCTA, including peripapillary retinal nerve fiber layer (RNFL) thickness and vessel density (VD) of the optic disc, superficial vessel plexus (SVP), deep vessel plexus (DVP), and foveal density (FD 300). p < 0.017 is considered significant in multiple comparisons. A total of 185 participants (65 NOCAD, 62 OCAD, and 58 controls) were enrolled. Except for the DVP fovea (p = 0.069), significantly reduced VD in all other regions of SVP and DVP was detected in both the NOCAD and OCAD groups compared to control group (all p < 0.017), while a more significant decrease was found in OCAD compared to NOCAD. Multivariate regression analysis showed that lower VD in superior hemi part of whole SVP (OR: 0.582, 95 % CI: 0.451–0.752) was an independent risk factor for NOCAD compared to controls, while lower VD in the whole SVP (OR: 0.550, 95 % CI: 0.421–0.719) was an independent risk factor for OCAD compared to NOCAD. Using the integration of retinal microvascular parameters, the area under the receiver operating characteristic curve (AUC) for NOCAD versus control and OCAD versus NOCAD were 0.840 and 0.830, respectively. Significant retinal microcirculation impairment, while milder than that in OCAD was observed in NOCAD patients, indicating retinal microvasculature assessment might provide a new systemic microcirculation observation window for NOCAD. Furthermore, retinal microvasculature may serve as a new indicator to assess the severity of CAD with good performance of retinal microvascular parameters in identifying different CAD subtypes. • Significant retinal microcirculation impairment appears in patients with non-obstructive coronary artery disease. • Retinal microcirculation impairment in non-obstructive subtype is milder than obstructive subtype of coronary artery disease. • Retina could be a new window for evaluating systemic microvascular impairment in non-obstructive coronary artery disease. • Retinal optical coherence tomography angiography could assist in identifying different coronary artery disease subtypes. [ABSTRACT FROM AUTHOR]

Precipitation changes such as more frequent drought and altered precipitation seasonality may impose substantial impacts on the structure and functioning of forest ecosystems. A better understanding of tree responses to precipitation changes can provide fundamental information for the conservation and management of forests under future climate regimes. We conducted a 2-year seasonal rainfall redistribution experiment to assess the responses of tree transpiration and growth to manipulated precipitation changes in a subtropical evergreen broad-leaved forest. Three precipitation treatments were administered including a drier dry season and wetter wet season treatment (DD), an extended dry season and wetter wet season treatment (ED), and an ambient control treatment, with the total amount of annual rainfall being kept the same among the three treatments. Our results showed that the DD and ED treatments reduced daily transpiration of Schima superba by 8-16 and 13-25%, respectively. The ED treatment also reduced the DBH increment of larger S. superba individuals. In contrast, neither treatment showed obvious effects on the transpiration and DBH increment of another dominant species Michelia macclurei. However, the transpiration of both species showed clear inter-annual differences between the 2 years with contrasting annual rainfall (2094 vs 1582 mm). S. superba had a lower transpiration-to-precipitation ratio (T/P) compared to M. macclurei and showed decreased sensitivities to total solar radiation and vapor pressure deficit under the DD and ED treatments. These results indicate the deep-rooted S. superba may be suppressed with a lower ability to obtain water and assimilate carbon compared to the shallow-rooted M. macclurei under the precipitation seasonality changes, which could potentially cause shifts in species dominance within the forest community. [ABSTRACT FROM AUTHOR]

Increasing air temperature and atmospheric CO 2 concentrations ( C a ) can profoundly affect photosynthesis and intrinsic water-use efficiency ( iWUE ). However, the response of trees in boreal permafrost regions to rapid warming and C a increases is poorly constrained by prior research. Here, we evaluated long-term changes in growth (using regional curve standardization [RCS]) and iWUE of Dahurian larch ( Larix gmelinii ) and Mongolian pine ( Pinus sylvestris var. mongolica ) in the boreal permafrost region of northeastern China and species-specific responses to increasing C a and temperature. From 1930–2010, RCS growth of Dahurian larch and Mongolian pine decreased, while iWUE increased by 25.5 and 21.1%, respectively. RCS growth of both species was negatively correlated with winter temperatures, but Mongolian pine depended most strongly on previous December to current February temperatures and Dahurian larch depended most strongly on March temperatures. Moisture conditions only weakly influenced growth. We found similar long-term changes of tree-ring δ 13 C in the two species. Carbon isotopic discrimination of Dahurian larch and Mongolian pine was determined mainly by growing season temperature (positive) and moisture (negative), but with different signal strengths, suggesting that stomatal conductance influenced tree-ring δ 13 C. Commonality analysis showed that RCS growth was affected mainly by temperature, but also by the combined effect (interaction) of iWUE and temperature. However, the contribution of iWUE alone was lower for Mongolian pine. Our results suggest that the increased iWUE caused by increasing C a will not improve tree growth sufficiently to compensate for temperature-induced water stress. The rate of temperature increase has slowed around 1990, which would have stabilized the degree of temperature-induced water stress, and this could be helpful to tree growth recovery in the permafrost region of northeastern China. [ABSTRACT FROM AUTHOR]

Microorganisms play critical ecological roles in the global biogeochemical cycles. However, extensive information on the microbial communities in Qinghai-Tibet Plateau (QTP), which is the highest plateau in the world, is still lacking, particularly in high elevation locations above 4500 m. Here, we performed a survey of th e soil and water microbial communities in Bamucuo Lake, Tibet, by using shotgun metagenomic methods. In the soil and water samples, we reconstructed 75 almost complete metagenomic assembly genomes, and 74 of the metagenomic assembly genomes from the water sample represented novel species. Proteobacteria and Actinobacteria were found to be the dominant bacterial phyla, while Euryarchaeota was the dominant archaeal phylum. The largest virus, Pandoravirus salinus, was found in the soil microbial community. We concluded that the microorganisms in Bamucuo Lake are most likely to fix carbon mainly through the 3-hydroxypropionic bi-cycle pathway. This study, for the first time, characterized the microbial community composition and metabolic capacity in QTP high-elevation locations with 4555 m, confirming that QTP is a vast and valuable resource pool, in which many microorganisms can be used to develop new bioactive substances and new antibiotics to which pathogenic microorganisms have not yet developed resistance. • The 3-hydroxypropionate bi-cycle pathway works in Bamucuo Lake. • Seventy-four metagenomic assembly genomes represented novel species. • Pandoravirus salinus was found in the in nearshore soil samples. • The dominant Actinobacteria can be used to develop new bioactive substances. [ABSTRACT FROM AUTHOR]

The Qinling Mountains (Qinling Mts.) are characterized as a distinct transition of bioclimatic zones along the north-south geographic boundary in China. Although ongoing global warming may affect the growth of most tree species across elevation gradients, the effect of modern warming on the stable hydrogen isotopes of tree-ring wood is still unknown. In this study, we developed early- and late-wood δ 2H chronologies from 1900 to 2018 CE of lignin methoxy groups (δ 2H LM) at 700-m intervals from 1700 to 3100 m a.s.l. along the elevation gradient in Mount Taibai (Mt. Taibai), the peak of the Qinling Mts. The δ 2H LM values of the earlywood were relatively enriched in 2H compared to the latewood, and an elevation-dependent depleting trend along the altitudinal gradient was observed. Comparing the δ 2H LM values with modelled δ 2H values of precipitation (δ 2H Pre) of the sample sites, similar isotopic patterns can be obtained. The reconstructions of δ 2H Pre values confirm the strong coherence between the isotopic composition of the source water and the methoxy groups in the growing season. The consistency of δ 2H LM chronologies between the early- and late-wood at the higher sites was stronger than that at the lower sites. The additional lagged effect and climate response revealed significant seasonal and altitudinal differences. At the timberline site, δ 2H LM values of earlywood were mainly related to the January and February temperatures, whereas δ 2H LM values of latewood correlated most strongly with temperature from July to September, and both values were controlled by the amount of total precipitation. In addition, the combined new δ 2H LM chronologies, based on the lag-1 autocorrelation and the weighted average of the current year earlywood and previous latewood, could be used to merge the corresponding temperature signals from the middle- and low-elevation sites. Altitudinal correlations of elevation offset between the annual δ 2H LM chronologies and interpolations of precipitation and temperature suggested that the δ 2H LM values at higher elevations better represent regional climatic changes. Therefore, topographic effects such as elevation differences should be considered in large-scale applications of δ 2H LM values in future studies. • Altitude- and seasonal-differences in δ 2H values of both tree-ring wood and precipitation were revealed in Qinling Mountains, China. • Elevational effects of temperature and precipitation resulted in the variations of δ 2H LM of lignin methoxy. • Timberline δ 2H LM recorded the significantly lagged effects and strong hydroclimatic signals. • Altitude specificity of δ 2H LM should be considered in the large-scale investigations. [ABSTRACT FROM AUTHOR]

Tree ring δ 13 C as a climate proxy is widely used for palaeoclimate research, however, its temporal stability response to the climate change remains unclear under more than one limited factors on tree growth. Here, we used a millennium tree-ring δ 13 C chronology combining two annual-resolution δ 13 C chronologies since 1800 from long-lived Qilian juniper ( Sabina przewalskii ) to assess its instability of the climate signal in the northeastern Qinghai–Tibetan Plateau. Tree-ring δ 13 C chronologies were strongly correlated with the regional mean April to August temperature from 1956 to 2008, but the associations were absent within the period 1901 to 1955 values in the CRU TS dataset. Comparison of the millennium-long δ 13 C series with reconstructed Asian temperatures also demonstrated that the δ 13 C chronology exhibited climate signal temporal instability. Substantial oscillations were revealed using a frequency-dependent analysis and 51-year running correlation analysis from the millennium-long tree-ring δ 13 C and δ 18 O series. Dual-isotope approach indicated that stomatal limitations created a statistical significant positive correlation between tree-ring δ 13 C and δ 18 O, but photosynthetic rate may be dominant when the correlations were not significant. Our results suggest that tree-ring δ 13 C series in the northeastern Qinghai–Tibetan Plateau is responded instability to temperature variations in the past 1000 years. [ABSTRACT FROM AUTHOR]

Canopy stomatal ozone (O 3 ) flux ( F st,O3 ) in a plantation of Schima superba , an ecologically and economically important evergreen pioneer tree species in subtropical China, was quantified based on sap flow measurements during a 2-year period. Mean F st,O3 and accumulated F st,O3 ( AF st 0) were significantly higher in wet seasons from April to September (4.62 nmol m − 2 s − 1 and 35.37 mmol m − 2 , respectively) than in dry seasons from October to March (3.90 nmol m − 2 s − 1 and 24.15 mmol m − 1 , respectively), yet comparable between the 2 years of the experiment, being 4.23 nmol m − 2 s − 1 and 58.23 mmol m − 2 in April 2013–March 2014 and 4.29 nmol m − 2 s − 1 and 60.80 mmol m − 2 in April 2014–March 2015, respectively. At the diurnal scale, F st,O3 generally peaked in the early to middle afternoon hours (13:00–15:00), while the maximum stomatal conductance ( G st,O3 ) typically occurred in the middle to late morning hours (09:00–11:00). Monthly integrated AF st 0 reached the maximum in July, although accumulated O 3 exposure ( SUM 0) was highest in October. Seasonally or yearly, the accumulated O 3 doses, either exposure-based or flux-based, notably exceeded the currently adopted critical thresholds for the protection of forest trees. These results, on the one hand, demonstrated the decoupling between the stomatal uptake of O 3 and its environmental exposure level; on the other hand, indicated the potential O 3 risk for S. superba in the experimental site. Therefore, the present study endorses the use of sap flow measurements as a feasible tool for estimating F st,O3 , and the transition from the exposure-based toward flux-based metrics for assessing O 3 risk for forest trees. Further studies are urgently needed to relate stomatal O 3 uptake doses with tree growth reductions for an improved understanding of O 3 effects on trees under natural conditions. [ABSTRACT FROM AUTHOR]

Tree growth in the mid-latitudes of the northern hemisphere reveals significant inter-annual variation in carbon sequestration, and the variations have been widely attributed to climate change, especially to the recent rapid warming and increasing drought stress. However, the response of natural trees under the different regions that exist in the northeastern Qinghai-Tibetan Plateau remains unclear. Here, we use nine Qilian juniper ( Sabina przewalskii) tree-ring width and basal area increment (BAI) chronologies from the middle of the Qilian Mountains and the northeastern Qaidam Basin to quantify tree growth trends and their response to the recent rapid warming. The trees, growing at high and low elevations, exhibited a consistent pattern of inter-annual variations, with increasing synchronicity in their trends since 1950. Responses to several climate factors indicate that increasing temperature accelerated tree growth in the middle of the Qilian Mountains, but restricted tree growth in the northeastern Qaidam Basin. Moving-window correlation analyses demonstrate a clearly contrasting response to the temperature variations. Our findings suggest that growth of Qilian juniper in the middle of the Qilian Mountains will increase steadily in the future rapid warming, but may remain constant or even decrease in the northeastern Qaidam Basin. These contrasting responses to temperatures provide valuable information on forest dynamics in the critical mid-latitude regions that should be incorporated into predictions of future forest carbon cycling under global warming. [ABSTRACT FROM AUTHOR]

Flash drought is an extreme phenomenon, characterized by unusually rapid intensification of drought severity, with strong impacts on plant growth especially for crops. However, it's unclear how hydrometeorological changes contribute to flash drought and how vegetation physiology, greenness, and productivity respond to flash drought. In this study, we developed an multivariate integrated framework for flash drought identification using a regression model based on principal-components analysis (PCA): the PCA regression flash drought (PRFD) model. Three criteria are specified to emphasize the rapid intensification of drought and its impacts on vegetation growth and water resources. We applied our new model in two geographical units with different climates and hydrology: one is dominated by agriculture and subject to natural drought (the Loess Plateau) and the other, a natural region with infrequent drought (the Qinling Mountains). We found that high frequency of flash droughts is most likely to occur in the eastern and central Loess Plateau and part of the Qinling Mountains. However, in relatively humid areas, flash drought shows strong intensity such as the Qinling Mountains and western and eastern edges of the Loess Plateau. Trend analysis indicates that PRFD has increased frequency, longer duration, and stronger intensity since the 1990s in both regions. From an ecological perspective, PRFD also showed a spatial pattern consistent with values of vegetation-related proxies that were below the long-term average, demonstrating vegetation transpiration, normalized-difference vegetation index (NDVI), gross primary productivity have obvious feedback on flash drought events. The Loess Plateau's NDVI responded immediately to flash drought, versus a 1-month lag in the Qinling Mountains. Because our proposed framework integrates multiple aspects of drought information, it can be applied in areas outside the study region according to regional hydrometeorological conditions. This has significant implications for improving agricultural management and forecasting future severe impacts of flash drought on plant growth. • A new integrated framework is proposed to identify flash drought (FD) events. • FD with greater frequency, longer pentads, and stronger intensity since 1990s. • Vegetation structure and physiological function respond rapidly to FD. • The response time of plant activity to FD is different in diverse climate-water regions. [ABSTRACT FROM AUTHOR]

Stable hydrogen isotope ratios (δD) in tree rings are an attractive but still rarely explored terrestrial archive of past climatic information. Because the preparation of the cellulose nitrate for δD measurements requires more wood and a longer preparation time than preparation techniques for other isotopes in cellulose (δ 18 O or δ 13 C), it is challenging to obtain high-resolution records, especially for slow-growing trees at high elevations and in boreal regions. Here, we tested whether annually pooled samples of Qinghai spruce ( Picea crassifolia Kom.) trees from northwestern China provided results similar to those derived as the mean of individual measurements of the same trees and whether the resulting chronologies recorded useful climate information. Inter-tree variability of δD was higher than that of measured ring width for the same trees. We found higher and significant coherence between pooled and mean isotope chronologies than that among the individual series. It showed a logarithmic relationship between ring mass and δD; however, accounting for the influence of ring mass on δD values only slightly improved the strength of climatic signals in the pooled records. Tree-ring δD was significantly positively correlated with the mean, maximum, and minimum temperatures during the previous winter and with maximum temperature during the current August, and significantly negatively correlated with precipitation in the previous November to January and the current July. The winter climate signal seems to dominate tree-ring δD through the influence of large-scale atmospheric circulation patterns, i.e. the Arctic Oscillation. These results will facilitate reconstruction of winter atmospheric circulation patterns over northwestern China based on a regional tree-ring δD networks. [ABSTRACT FROM AUTHOR]

ABSTRACT We developed an annual tree-ring δ18O chronology from Larix sibirica in the eastern Tianshan Mountains of northwestern China. Climatic response revealed that tree-ring δ18O was significantly positively correlated with the mean and maximum July-August temperatures, whereas the July precipitation and relative humidity were significantly negatively correlated with tree-ring δ18O. The self-calibrating Palmer drought severity index (sc_PDSI) in July-August was significantly correlated with the tree-ring δ18O, which reflects the comprehensive effects of the three parameters on tree-ring δ18O fractionation. We established a robust reconstruction of July-August sc_ PDSI that accounted for 38.4% of the total variance of sc_PDSI from 1959 to 2008. The sc_PDSI reconstruction yields new insights on past drought that were not previously realized in other PDSI reconstructions (e.g. Monsoon Asia Drought Atlas) from the region. The reconstruction revealed several wet and dry periods but no trend towards a wetter climate in the eastern Tianshan Mountains during the last two decades. It also detected synergistic effects of the North Atlantic Oscillation and the El Niño-Southern Oscillation on regional moisture conditions as a result of teleconnections between tropical oceans and mid-latitude circulation patterns. [ABSTRACT FROM AUTHOR]

The rising atmospheric CO2 concentration (Ca) has increased tree growth and intrinsic water-use efficiency (iWUE). However, the magnitude of this effect on long-term iWUE and whether this increase could stimulate the growth of riparian forests in extremely arid regions remain poorly understood. We investigated the relationship between growth [ring width; basal area increment (BAI)] and iWUE in a riparian Populus euphratica Oliv. forest to test whether growth was enhanced by increasing CO2 and whether this compensated for environmental stresses in the lower reaches of the inland Heihe River, northwestern China. We accomplished this using dendrochronological methods and carbon (δ13C) and oxygen (δ18O) isotopic analysis. We found an increase in BAI before 1958, followed by a decrease from 1958 to 1977 and an increase to a peak around 2000. Tree-ring carbon discrimination (Δ) and δ18O indicated significant negative overall trends from 1920 to 2012. However, the relationship shifted in strength and direction around 1977 from significantly negative to a weak connection. The seasonal minimum temperature in April to July showed strong influence on Δ, and δ18O was controlled by relative humidity (negatively correlated) and temperature (positively correlated) in June and July. The patterns of internal to atmospheric CO2 (Ci/Ca) suggest a specific adaptation of tree physiology to increasing CO2. Intrinsic water-use efficiency increased significantly (by 36.4%) during the study period. The increased iWUE explained 19.8 and 39.1% of the observed yearly and high-frequency (first-order difference) variations in BAI, respectively, after 1977. Our results suggest significant CO2 stimulation of riparian tree growth, which compensated for the negative influences of reductions in river streamflow and a drying climate during the study period. [ABSTRACT FROM AUTHOR]

We measured the annual variation in the stable isotopes of oxygen (δO) and hydrogen (δD) in tree rings of Abies georgei on the Batang-Litang Plateau of western China. Although correlations between tree-ring δO and δD are relatively weak in semi-arid regions, we found a strong correlation between the δO and δD time series from 1755 to 2009 under the wetter environment. Tree-ring δO and δD time series are both significantly and negatively correlated with moisture conditions from June to August, including relative humidity and total precipitation, respectively, from 1960 to 2009. Considering the difference in low-frequency domain between the two isotopes, the relative humidity histories from June to August, reconstructed separately from the tree-ring δO and δD data with instrumental climate data, reveal a persistent drying trend since 1850s, especially since the early 1970s. There is an obvious offset of reconstructed relative humidity from tree-ring δO and δD in the period 1755-1820, despite the strong similarity in their 21-year moving averages. The decreased relative humidity since the 1850s may be associated with the thermal contrast between the sea surface temperature of the Indian Ocean and the Qinghai-Tibetan Plateau, which determines the strength of moisture transfer via the Indian summer monsoon. [ABSTRACT FROM AUTHOR]

Annual tree ring δO and δC chronologies from 1790 to 2008 were established using Tianshan spruce ( Picea schrenkiana) in the central Tianshan Mountains of northwestern China. Temperature has a positive effect on tree ring δO and δC in the study area, while precipitation and relative humidity have negative effects. The standardized precipitation-evapotranspiration index (SPEI) considered all of these effects and was significantly negatively correlated with tree ring δO and δC. We combined the tree ring δO and δC series to reconstruct the past 192 years of SPEI, which accounted for about 46 % of the total variance of SPEI from 1950 to 2006. The reconstruction showed good spatial agreement with gridded data in Palmer Drought Severity Index and precipitation and an inverse relationship with temperature. Our SPEI reconstruction reveals several wet and dry periods over the past 192 years and has good agreement with other drought records. Wavelet analysis showed quasi-periodic 10-, 20-, 30-, and 70-year fluctuations in the reconstruction. The 10-, 20-, and 30-year periodicities may reflect the potential influence of North Atlantic Oscillation (NAO). Overall, this study indicates that the SPEI is a potential drought index, and the winter NAO affects regional moisture conditions in the long term. [ABSTRACT FROM AUTHOR]