Search

The Hindu Kush high-altitude regions of Pakistan are currently experiencing severe consequences as a result of global warming. In this sense, increasing soil erosion and the quick melting of glaciers are two particularly evident effects. In such a scenario, understanding long-term temperature changes is crucial for making accurate forecasts about how the Hindu Kush region may experience regional temperature changes in the future. In this study, the climate tree-ring width (TRW) analysis designated a positive and significant correlation (r = 0.622, p < 0.001) between the TRW chronology and the June to September (summer) mean maximum temperature (MMT). Using the tree-ring width of Pinus wallichiana A. B. Jackson, we reconstructed summer temperatures in the Hindu Kush region from 1790 CE. Statistical analysis showed that the reconstruction model has explained 38.7% of the climate variance during the instrumental period of 1967 to 2018 CE. Five extremely warm summer periods (≥ 4 years; before the instrumental period 1967–2018 CE) of 1804–1830, 1839–1862, 1876–1879, 1905–1910, 1923–1935 CE, and six cold summer periods of 1790–1803, 1832–1838, 1863–1875, 1880–1904, 1911–1922, and 1936–1945 CE have been observed during the past 229 years. Individually, the year 1856 CE experienced severe warmth (31.85 °C), whereas 1794 CE was relatively cooler (29.60 °C). The spectral multi-taper method (MTM) shows significant (p < 0.05) cycles, which take place about every 9.3, 5.7, 4.2, and 3.6 years. In particular, the 9.3-year cycle, which closely aligns with the 11-year solar activity cycle, suggests a potential correlation between solar activity and local temperature fluctuations. Moreover, our reconstruction demonstrates a significant degree of consistency when compared to actual climate data and regional temperature reconstruction series, reporting a strong logic of trust in the reliability and accuracy of our findings. This evidence reaffirms that our reconstruction shows significant and dependable regional temperature signals, notably being representative for the Hindu Kush region. [ABSTRACT FROM AUTHOR]

Analyses of stable isotopes (C, O, H) in tree rings are increasingly important cross-disciplinary programs. The rapid development in this field documented in an increasing number of publications requires a comprehensive review. This study includes a bibliometric analysis-based review to better understand research trends in tree ring stable isotope research. Overall, 1475 publications were selected from the Web of Science Core Collection for 1974–2023. The findings are that: (1) numbers of annual publications and citations increased since 1974. From 1974 to 1980, there were around two relevant publications per year. However, from 2020 to 2022, this rose sharply to 109 publications per year. Likewise, average article citations were less than four per year before 1990, but were around four per article per year after 2000; (2) the major subjects using tree ring stable isotopes include forestry, geosciences, and environmental sciences, contributing to 42.5% of the total during 1974–2023; (3) the top three most productive institutions are the Chinese Academy of Sciences (423), the Swiss Federal Institute for Forest, Snow and Landscape Research (227), and the University of Arizona (204). These achievements result from strong collaborations; (4) review papers, for example, (Dawson et al., Annu Rev Ecol Syst 33:507–559, 2002) and (McCarroll and Loader, Quat Sci Rev 23:771–801, 2004), are among the most cited, with more than 1000 citations; (5) tree ring stable isotope studies mainly focus on climatology and ecology, with atmospheric CO2 one of the most popular topics. Since 2010, precipitation and drought have received increasing attention. Based on this analysis, the research stages, key findings, debated issues, limitations and directions for future research are summarized. This study serves as an important attempt to understand the progress on the use of stable isotopes in tree rings, providing scientific guidance for young researchers in this field. [ABSTRACT FROM AUTHOR]

Long-term high resolution climate proxies are essential for understanding climate variability particularly, in regions such as the western Himalayas of northern Pakistan, where few long-term climate records are available. Using standard dendrochronological methods, an 1132-year (882 to 2013 C.E.) tree-ring chronology of Juniperus excelsa M. Bieb was established from the western Himalayas, northern Pakistan (WHNP). Tree growth was negatively and significantly (r = −0.65) correlated with the growing season (June–July) mean temperature, and positively and weakly (r = 0.22) associated with precipitation. This inverse relationship of tree radial growth with temperature and positive association with precipitation demonstrated that forest growth is sensitive to high temperature related drought. Utilizing a reliable STD chronology and robust reconstruction model, a 928-year (1086 to 2013 C.E.) mean temperature reconstruction was developed for the WHNP using the substantial negative correlation between the summer temperature and standard tree ring-width chronology. According to statistical validation, the reconstruction accounted for 41.6% of the climatic variation for the period of 1956–2013 C.E. instrumental period. Individual extreme-warm periods occurred in 1093 C.E. (29.42°C) and extreme cold periods in 1088 C.E. (26.99°C) observed during the past 928 years. The reconstruction's multi-taper method (MTM) spectral analysis reveals significant (p < 0.05) 2–3-year and 63.8-year cycles. Since the 2–3-year cycle occurred within the range of ENSO variation, which indicates that ENSO had an impact on the regional temperature in our studied area. [ABSTRACT FROM AUTHOR]

As an important component of the stirling-type pulse tube cryocooler (SPTC), an efficient phase shifter can significantly improve the cooling capacity. Compared to the common phase shifter, the active warm displacer (AWD) has a wider phase adjustment range and therefore can obtain a better phase relationship easily. Based on a two-stage thermal-coupled SPTC operating in the 20 K range, this paper studied the influence of the swept volume ratio between the compressor and displacer. The research found that the swept volume ratio changes the cooling capacity and efficiency of the cryocooler mainly by changing the phase difference between the pressure wave and the volume flow at the cold end. It was found from the results of the simulation and experiments that there is an optimal displacement of the displacer (Xd) of 2.5 mm and an optimal phase angle of 15° to obtain the highest cooling efficiency while the displacement of the compressor is constant. The cooling capacity at 20 K is 1.3 W while the input electrical power of the second stage compressor is 202 W, which indicates an overall relative Carnot efficiency (rCOP) of 0.055 in terms of input electrical power. In addition, due to the reasonable setting of precooling temperature and capacity, the swept volume ratio and phase at the maximum cooling capacity and maximum efficiency are consistent in this study. The research improves the understanding of phase shifters and has guiding significance for the optimization of the SPTC working below 20 K. [ABSTRACT FROM AUTHOR]

Bismuth vanadate (BiVO4, BVO) as a promising photoelectrode has been received great attention for photoelectrochemical (PEC) water splitting. However, the slow oxidation kinetics on the surface of BiVO4 limited the PEC water splitting efficiency. Herein, nickel boride (Ni3B, NB) nanoparticles, generally used in electrocatalytic field material, were modified on the surface of BiVO4 photoelectrode as an efficient cocatalyst to accelerate the oxygen evolution reaction. The as-prepared BVO-NB-5P photoelectrode exhibits a remarkable photocurrent density of 1.47 mA·cm−2 at 1.23 V versus the reversible hydrogen electrode (RHE) under air mass (AM) 1.5 G illumination, which is about 2.8 times higher than the bare BiVO4 photoelectrode, and its water splitting rate is 11.3 times higher than bare BiVO4. The PEC studies reveal that the spin coated Ni3B crystal cocatalyst could effectively reduce the water oxidation barrier, and improve the surface charge injection efficiency to 94%, which could boost the photogenerated holes reaction to enhance the PEC performance of BiVO4 photoelectrode. [ABSTRACT FROM AUTHOR]

A two-stage gas-coupled Stirling/pulse tube refrigerator (SPR), whose first and second stages respectively involve Stirling and pulse tube refrigeration cycles, is a very promising spaceborne refrigerator. The SPR has many advantages, such as a compact structure, high reliability, and high performance, and is expected to become an essential refrigerator for space applications. In research regarding gas-coupled regenerative refrigerator, the energy flow distribution between the two stages, and optimal phase difference between the pressure wave and volume flow, are two critical parameters that could widely influence refrigerator performance. The effects of displacer displacement on the pressure wave, phase difference, acoustic power distribution, and inter-stage cooling capacity shift of the SPR have been investigated experimentally. Notably, to obtain the maximum first-stage cooling capacity, an inflection point in displacement exists. When the displacer displacement is larger than the inflection point, the cooling capacity could be distributed between the first and second stages. In the present study, an SPR was designed and manufactured to work between the liquid hydrogen and liquid oxygen temperatures, which can be used to cool small-scale zero boil-off systems and space detectors. Under appropriate displacer displacement, the SPR can reach a no-load cooling temperature of 15.4 K and obtain 2.6 W cooling capacity at 70 K plus 0.1 W cooling capacity at 20 K with 160 W compressor input electric power. [ABSTRACT FROM AUTHOR]

Diabetes is mainly caused by abnormal increase of blood glucose level, the corresponding glucose sensor can be used to monitor the concentration of glucose. TiO2/NiOOH composite sensor was prepared by a facile method of electrodeposition of NiOOH on TiO2 nanotube arrays (TNT), and triangle Ag sheets modified by photodeposition. The structures and photoelectric properties were characterized by electrochemical workstation. It was found that NiOOH could effectively improve the photoelectrochemical properties of TNT. When Ag was further photodeposited on TNT/NiOOH, the photocurrent density improved at 0.21 mA/cm2. The enhanced photoelectrochemical properties can be attributed to the extended visible light absorption and effective separation of photo-generated carriers by the synergistic effect of Ag and NiOOH. The modified TNT/NiOOH exhibited much stronger photoelectrochemical reduction property toward glucose in comparison to pure TNT. The sensitivity of TNT/NiOOH/Ag to glucose can reach 2490 μA·cm−2·mM−1 and its detection limit low to 0.44 μM. [ABSTRACT FROM AUTHOR]

The Stirling-type pulse tube refrigerator is a widely used refrigerator that has been extensively applied in space. An optimal phase angle between the pressure wave and volume flow is essential for a pulse tube refrigerator. The active displacer installed at the hot end of a pulse tube can be used to actively control the phase angle and enable recovery of the expansion power at the warm end of the pulse tube, leading to high efficiency. The main parameters for a pulse tube refrigerator with an active displacer are the phase and displacement of the active displacer. This manuscript studies the impact of displacer phase and displacement on a 40 K single-stage pulse tube refrigerator with an active displacer by thermoacoustic analysis, which is helpful for studying the thermodynamic characteristics of such a refrigerator and provides a method for more effective design and computing. The effects on the pressure, acoustic power, and cooling capacity are investigated by analytically solving the thermoacoustic model. A pulse tube refrigerator developed in our laboratory is tested, and the experimental results are compared with the results of thermoacoustic analysis. [ABSTRACT FROM AUTHOR]

Sludge incineration is one of the most efficient sludge treatment methods. The fly ash produced by incineration must be handled further since it has a significant number of heavy metals. In this study, the chemical composition of sewage sludge incineration fly ash (SSA) generated from Zhejiang in various months was identified by XRD, X-ray fluorescence spectrometer (XRF), and SEM analyzes. The SSA were treated by a (NH4)2SO4 roasting-acid leaching process to determine its effect on the elimination performance of heavy metals. The SSA content on the mechanical properties and heavy metal leaching of modified SSA-filled PP composite were also studied. Results show (NH4)2SO4 roasting-acid leaching process has a good effect of eliminating heavy metals, with the highest leaching of Zn of 86.4%. The presence of sodium stearate modifier increases activation index of SSA and then improves the compatibility of SSA particles in PP, resulting for the composites have relatively excellent mechanical properties. For the toxicity characteristic leaching procedure (TCLP) test, modified SSA particles can be effectively encapsulated with PP resins, which have a considerable inhibitory effect on heavy metal leaching. This process from this study provides a reference for sewage sludge treatment by using modified SSA as a polymer filler to achieve the immobilization of heavy metals and the resource recycling. [ABSTRACT FROM AUTHOR]

Key message: Pine benefited from a warming climate with increasing recruitment and upslope shifts of alpine treeline but birch treelines were mostly static highlighting the influence of other confounding, local factors. Alpine treeline is considered as a sensitive indicator to climate change. Given that low temperature is a primary constraint of treeline dynamics, they are expected to shift upslope in response to climate warming. The Karakoram, under westerly-dominated climate, has experienced significant warming since the mid-nineteenth century. However, in comparison to monsoon-dominated wetter areas, little is known how alpine treelines have responded to rising temperatures in westerly-dominated dry areas, such as the Karakoram. To test if climate warming triggered upslope shift of alpine treelines in the Karakoram, we compared the recent dynamics of blue pine (Pinus wallichiana) and Himalayan birch (Betula utilis) treeline populations. We expected a higher responsiveness of pine recruitment to temperature as compared with birch due to the higher drought-tolerance of pine species. Tree mapping and dendrochronological methods were used to determine stand age structure, and to reconstruct spatiotemporal treeline dynamics during the past 150 years. The decadal recruitment rate of pine was positively correlated with summer and winter temperatures, whereas the birch recruitment was negatively correlated. Accordingly, pine treelines showed significant upslope shifts in two out of three plots, whilst two birch treelines remained stable in the two studied plots. Such different treeline shift rates between blue pine and birch species agree with their divergent recruitment responses to climate warming. Thus, projected warming in the Karakoram will differently impact treelines depending on species-specific responses with pine showing a more dynamic and rapid upward treeline advancement and birch showing less rapid responses. However, we should consider other non-climatic factors such as anthropogenic disturbances for better understanding treeline dynamics in the Karakoram. [ABSTRACT FROM AUTHOR]

Tree growth is ordinarily affected by changes in environmental conditions, and the annual sequence of favorable and unfavorable climates is regularly recorded in wide and narrow tree rings. Therefore, data extracted from tree rings can be adopted to reconstruct the past climate. In dendroclimatology, the commonly used proxy indices to obtain paleoclimatic parameters include tree-ring width, blue intensity, density, and isotopic series. Notwithstanding, reconstructing the past local climatic parameters with high accuracy is a challenge. Here, we demonstrate how data from microscopic-hyperspectral scanning of the dendrochronological samples, together with the tree-ring width data, facilitates the precise estimation of one paleoclimatic parameter, the mean deviation of monthly air temperature. In a proof-of-concept analysis experiment, samples were collected from two sites located in the middle part of China, measured with a hyperspectral scanning system, model achieved an averaged root mean square error (RMSE) of 0.524℃ on the mean deviation of monthly air temperature from March to July, which demonstrates significant improvements in accuracy compared with the classical single-indexed tree-ring width method, especially when the number of tree-ring samples is limited. Further, our results suggest that climatic data stored in the tree-ring spectrum could be divulged by analyzing their surface hyperspectral reflectance. We hope our work will be a genesis for more intricate models in dendroclimatology that use microscopic-hyperspectral scanning as a standard tool, which promises enhanced accuracy for past climate reconstruction. Besides tree rings, the capacity of the microscopic-hyperspectral scanning technique can be exploited on other samples collected in paleoclimatology, including core samples from rocks, sediment, ice, or surface samples on shells, boreholes, and corals, to derive valuable information from their surface spectral patterns. [ABSTRACT FROM AUTHOR]

Melanoma cells display distinct intrinsic phenotypic states. Here, we seek to characterize the molecular regulation of these states using multi-omic analyses of whole exome, transcriptome, microRNA, long non-coding RNA and DNA methylation data together with reverse-phase protein array data on a panel of 68 highly annotated early passage melanoma cell lines. We demonstrate that clearly defined cancer cell intrinsic transcriptomic programs are maintained in melanoma cells ex vivo and remain highly conserved within melanoma tumors, are associated with distinct immune features within tumors, and differentially correlate with checkpoint inhibitor and adoptive T cell therapy efficacy. Through integrative analyses we demonstrate highly complex multi-omic regulation of melanoma cell intrinsic programs that provide key insights into the molecular maintenance of phenotypic states. These findings have implications for cancer biology and the identification of new therapeutic strategies. Further, these deeply characterized cell lines will serve as an invaluable resource for future research in the field. The regulation of the distinct intrinsic phenotypic states in melanoma remain poorly characterised. Here, multi-omics analysis for a panel of 68 early passage melanoma cell lines reveals that cancer cell intrinsic transcriptomic programs are associated with distinct immune features. [ABSTRACT FROM AUTHOR]

The unstable sensitivity of growth-climate relationships greatly restricts tree-ring-based paleoclimate reconstructions, especially in areas with frequent “divergence” problems, such as the monsoonal zone of Northeast China. Here, we test the proposition that the tree species mixing method can improve the stability and reliability of reconstruction models in monsoonal areas, taking the tree-ring-based growing-season minimum temperature reconstruction for the northern Changbai Mountains in Northeast China as an example. Compared with previous temperature reconstruction models, ours is more stable and reliable and explains up to 70.4% of the variance. Our reconstruction is also highly consistent with historical records and tree-ring-based temperature reconstructions from the nearby Laobai and Zhangguangcai Mountains and across the Northern Hemisphere. Our reconstruction uses two different tree species and is more accurate than temperature reconstructions developed from a single species. Six significant warm and four cold periods are identified over the past 247 years (AD 1769–2015). The reconstruction indicates rapid warming since the 1980s, which is consistent with other instrumental and reconstructed records. The Atlantic Multidecadal Oscillation and volcano eruptions play a crucial role in driving the growing-season minimum temperature in the northern Changbai Mountains. [ABSTRACT FROM AUTHOR]

Key messages: We reported an NBS-LRR gene, PsoRPM3, is highly expressed following RKN infection, initiating an HR response that promotes plant resistance. Meloidogyne spp. are root-knot nematodes (RKNs) that cause substantial economic losses worldwide. Screening for resistant tree resources and identifying plant resistance genes is currently the most effective way to prevent RKN infestations. Here, we cloned a novel TIR-NB-LRR-type resistance gene, PsoRPM3, from Xinjiang wild myrobalan plum (Prunus sogdiana Vassilcz.) and demonstrated that its protein product localized to the nucleus. In response to Meloidogyne incognita infection, PsoRPM3 gene expression levels were significantly higher in resistant myrobalan plum plants compared to susceptible plants. We investigated this difference, discovering that the − 309 to − 19 bp region of the susceptible PsoRPM3 promoter was highly methylated. Indeed, heterologous expression of PsoRPM3 significantly enhanced the resistance of susceptible tobacco plants to M. incognita. Moreover, transient expression of PsoRPM3 induced a hypersensitive response in tobacco, whereas RNAi-mediated silencing of PsoRPM3 in transgenic tobacco reduced this hypersensitive response. Several hypersensitive response marker genes were considerably up-regulated in resistant myrobalan plum plants when compared with susceptible counterparts inoculated with M. incognita. PsoPR1a (a SA marker gene), PsoPR2 (a JA marker gene), and PsoACS6 (an ET signaling marker gene) were all more highly expressed in resistant than in susceptible plants. Together, these results support a model in which PsoRPM3 is highly expressed following RKN infection, initiating an HR response that promotes plant resistance through activated salicylic acid, jasmonic acid, and ethylene signaling pathways. [ABSTRACT FROM AUTHOR]

To provide a long-term context for understanding the "Karakoram Anomaly" in recent glacier studies, we originally aimed to develop an annually resolved multi-century winter–spring precipitation record using tree-ring earlywood cellulose δ18O (δ18OEW) of Pinus wallachina from the Karakoram, northern Pakistan. Out of expectation, winter (January–May) temperature rather than precipitation is found to be the dominant climate signal (r = 0.63, p < 0.01, 1955–2013) stored in the δ18OEW chronology. Precipitation signals mainly appear at high-frequency variations, but weaker than temperature signal. We reconstructed January–May temperature back to 1631 with an explained variance of 39.7 % during the calibration period of 1955–2013. The reconstruction reveals that the Little Ice Age (LIA) was 0.94 °C warmer during 1647–1746 than the twentieth century (1900–1999). These warmer conditions are additionally validated by ice-core δ18O data from the Kunlun Mountains of High Asia and the northern North America. The eastward Polar Vortex and enhanced mid-latitude Westerlies on the Euro-Asia continent may be a possible explanation of a spatial coherency of LIA temperature between the Karakoram and the northern North America. Although not the original aim of this study, we provide evidence that the attribution of anomalous behavior of Karakoram glaciers in a long-term context may be misled when using precipitation reconstructions derived from tree-ring oxygen isotope. [ABSTRACT FROM AUTHOR]

A non-immunogenic tumor microenvironment (TME) is a significant barrier to immune checkpoint blockade (ICB) response. The impact of Polybromo-1 (PBRM1) on TME and response to ICB in renal cell carcinoma (RCC) remains to be resolved. Here we show that PBRM1/Pbrm1 deficiency reduces the binding of brahma-related gene 1 (BRG1) to the IFNγ receptor 2 (Ifngr2) promoter, decreasing STAT1 phosphorylation and the subsequent expression of IFNγ target genes. An analysis of 3 independent patient cohorts and of murine pre-clinical models reveals that PBRM1 loss is associated with a less immunogenic TME and upregulated angiogenesis. Pbrm1 deficient Renca subcutaneous tumors in mice are more resistance to ICB, and a retrospective analysis of the IMmotion150 RCC study also suggests that PBRM1 mutation reduces benefit from ICB. Our study sheds light on the influence of PBRM1 mutations on IFNγ-STAT1 signaling and TME, and can inform additional preclinical and clinical studies in RCC. PBRM1, encoding for a subunit of the SWI/SNF complex, is the second most frequently mutated gene in clear cell renal cell carcinoma (ccRCC). Here, the authors show that PBRM1 loss reduces IFNγ-mediated signalling resulting in a less immunogenic tumor microenvironment and that PBRM1 mutations correlate with lack of response to checkpoint inhibitor therapy in ccRCC patients.. [ABSTRACT FROM AUTHOR]

Aims: Alfalfa is the most important forage legume but sensitive to aluminum (Al), which largely limits its growth in acid soils. To improve Al resistance in alfalfa, responses to Al toxicity were investigated for understanding of the mechanisms of Al resistance in alfalfa. Methods: Growth performance and Al resistance in forty-two cultivars was evaluated. Organic acids synthesis and exudation as well as the key genes in response to Al were investigated. Results: Alfalfa cultivars showed diversity in Al resistance. Compared to the sensitive cultivar 'Magnum 801', the Al resistant cultivar 'WL414' had higher relative root elongation in response to Al toxicity, with less accumulation of Al. Al activated citrate and malate exudation in alfalfa, with higher citrate exudation and concentration as well as higher levels of citrate synthase (CS) activity, MsCS, MsALMT1, and MsMATE22 transcripts in root apex in WL414 than in Magnum 801. Citrate exudation is the major mechanism in Al resistance in alfalfa. Conclusions: Alfalfa cultivars had diversity in Al resistance. Citrate synthesis and exudation plays a key role in Al resistance in alfalfa. Higher levels of citrate concentration and exudation are associated with Al resistance in Al resistant cultivar as compared with the sensitive cultivar. [ABSTRACT FROM AUTHOR]

Key message: Warming-induced drought stress leads to convergent and negative growth responses to temperature between sympatric tree species, implying an increasing interspecific competition for soil moisture. In mixed forests, sympatric tree species avoid competition by partitioning their niches according to available environment resources. We raise the hypothesis that climate warming leads to a convergence in growth responses to climate, thus increasing the competition among sympatric species in drought-prone forests. In this study, we selected a mixed forest located at ca. 3600 m a.s.l in the Baima Snow Mountains, an inner dry valley of the southeastern Tibetan Plateau. We measured width of the tree rings produced during 1910–2016 in 60 trees belonging to three sympatric species: Abies georgei, Picea likiangensis, and Betula delavayi. We analyzed the changes in radial growth and their responses to climate. We detected shifts in the responses to climate after the 1990s. The radial growth of all species was positively correlated with precipitation from 1964 to 1990, but negatively correlated with March–June temperature from 1991 to 2016. Compared to the period 1964–1990, convergent and negative growth responses to warmer temperatures in the period 1991–2016 probably reflect less available soil moisture for growing in this mixed forest. We conclude that climate warming will affect the niches of sympatric species in mixed forests subjected to seasonal drought, thus increasing competition and altering structure and composition of the stands in dry regions. [ABSTRACT FROM AUTHOR]

This study examined the influence of biochar addition on fungal community during composting of cow manure using high-throughput sequencing. Two treatments were set up, including compost of cow manure plus 10% biochar (BC) and cow manure compost without biochar (CK). Fungal community composition varied obviously during composting in both treatments, and main fungi included Aspergillus, Myriococcum, Thermomyces, Mycothermus, Scedosporium, Cladosporium, and unclassified Microascaceae. Fungal community composition was altered by biochar during composting, especially during the thermophilic and the cooling phase, promoting Aspergillus and Myriococcum while inhibiting unclassified Microascaceae and Thermomyces. Based on linear discriminant analysis effect size analysis, common indicator groups were detected in both composts; however, specific indicator groups were also found in BC treatment, including Clavicipitaceae, Tremellales, Gibberella, and Coprinopsis. Canonical correspondence analysis (CCA) indicated that moisture content, organic matter, C/N, and pH had significant correlation (p < 0.05) with fungal composition in both treatments. However, in compost added with biochar, temperature was not an important factor affecting fungal community (p > 0.05). [ABSTRACT FROM AUTHOR]

Knowledge of past climatic variability for the Tibetan Plateau (TP), especially the northwestern part of it, is still limited due to the lack of long-term meteorological records. Within this study, we developed a summer (June–July) minimum temperature reconstruction since 1681 based on annual tree-ring width of Schrenk's spruce (Picea schrenkiana Fisch. et Mey.) from a humid timberline on the western Kunlun Mountains. Our reconstruction passed the statistical calibration and validation tests, and accounted for 37.69% of the variance for the instrumental record during the period 1960–1996. The reconstruction mainly exhibited annual to decadal temperature variability, with cold periods in 1694–1696, 1745–1749, 1823–1824, and 1915–1921, and warm periods in 1755–1760, 1795–1799, and 1894–1896. Spatial correlations and comparisons with the Asia summer temperature reconstructions further verified our temperature reconstruction and its capability to serve as a proxy for large-scale temperature variability on the northwestern TP. Our results clearly indicate the great potential to perform dendrochronological studies on the western Kunlun Mountains. [ABSTRACT FROM AUTHOR]

Climatic change is exhibiting significant effects on the ecosystem of the Tibetan Plateau (TP), a climate-sensitive area. In particularly, winter frost, freezing events and snow avalanche frequently causing severe effects on ecosystem and social economy, however, few long-term winter temperature records or reconstructions hinder a better understanding on variations in winter temperature in the vast area of the TP. In this paper, we present a minimum winter (November–February) temperature reconstruction for the past 668 years based on a tree-ring network (12 new tree-ring chronologies) on the southeastern TP. The reconstruction exhibits decadal to inter-decadal temperature variability, with cold periods occurring in 1423–1508, 1592–1651, 1729–1768, 1798–1847, 1892–1927, and 1958–1981, and warm periods in 1340–1422, 1509–1570, 1652–1728, 1769–1797, 1848–1891, 1928–1957, and 1982–2007. As suggested by the comparisons with existing winter temperature series and spatial correlations with Climatic Research Unit gridded data, our reconstruction is reliable and indicative, and it can represent large-scale winter temperature variability on the southeastern TP. Furthermore, it shows an overall agreement with winter temperature from the northeastern TP on decadal to inter-decadal timescales. It also shows the possible effects of volcanic eruption and reducing solar activity on the winter temperature variability for the past six centuries on the southeastern TP. [ABSTRACT FROM AUTHOR]

Key message: Moderate-severity fire disturbances can accelerate upslope shifts of alpine treelines by reducing interspecific interactions, providing additional evidence for the species interaction mechanism in controlling treeline dynamics. Biotic interactions between trees and other plants may modulate the responses of alpine treelines to climate. Moderate disturbances could, therefore, accelerate upward shifts of alpine treelines as the climate warms by reducing the coverage of competitor plants and resetting interspecific interactions. Larch (Larix potaninii var. macrocarpa) treelines disturbed by fire on the southeastern Tibetan Plateau are good locales for testing this hypothesis. We characterized treelines in five large rectangular plots spanning undisturbed and fire-disturbed fir (Abies georgei) and larch treelines. The fires in the 1960s caused gaps in the reconstructed age structures of the larches during the 1970s but did not lead to downslope shifts in treeline position. Recruitment has instead increased since the 1980s within the disturbed larch treelines, with treelines shifting upward by 11–44 m. In contrast, the undisturbed larch and fir treeline positions remained mostly unchanged. We hypothesize that upslope shifts of alpine treelines are likely a consequence of climatic warming, but fire disturbances can accelerate these dynamics by altering interspecific interactions. [ABSTRACT FROM AUTHOR]

The tree-ring cellulose oxygen isotopes (δ18O) for four trees of Hippophae tibetana and four trees of Abies georgei growing in different locations around the terminal moraine in Xincuo from 1951 to 2010 were measured to explore its potential for reconstructing climatic variations in the southeastern Tibetan Plateau. The mean and standard deviation of tree-ring δ18O at different heights do not have significant differences, and there are no significant differences in the mean and standard deviation of tree-ring δ18O between trees near the brook and trees at the top of moraine, indicating that we can collect samples for tree-ring δ18O analysis regardless of sampling heights and that the micro-environment does not affect tree-ring δ18O significantly. The mean inter-series correlations of cellulose δ18O for A. georgei/H. tibetana are 0.84/0.93, and the correlation between δ18O for A. georgei and H. tibetana is 0.92. The good coherence between inter-tree and inter-species cellulose δ18O demonstrates the possibility of using different species to develop a long chronology. Correlation analysis between tree-ring δ18O and climate parameters revealed that δ18O for A. georgei/H. tibetana had negative correlations (r = −0.62/r = −0.69) with relative humidity in July–August, and spatial correlation revealed that δ18O for A. georgei/H. tibetana reflected the regional Standardized Precipitation Evapotranspiration Index (29°–32° N, 88°–98° E). In addition, tree-ring δ18O in Xincuo has a significant correlation with tree-ring δ18O in Bhutan. The results indicate that cellulose δ18O for A. georgei and H. tibetana in Xincuo is a good proxy for the regional hydroclimate. [ABSTRACT FROM AUTHOR]

To observe the effect of DMEM/F12 pegylated with methoxy polyethylene glycol succinimidyl propionate (mPEG-SPA) on the biophysical and immune characteristics of the rat cornea preserved in it. Corneal grafts were harvested from Wistar rat and preserved in the DMEM/F12 plus mPEG-SPA, DMEM/F12 without mPEG-SPA, and standard Optisol-GS solution at 4 °C for 14 days, referred as plus-PEG, minus-PEG, and Optisol grafts, respectively. The biophysical properties of those grafts, including transmittance, thickness, water content, and biomechanics were investigated. The survival of those grafts was observed in the high-risk corneal transplantation model. Transmittance and biomechanics did not show any differences among those grafts. Thickness and water content of plus-PEG grafts were slightly improved. Proliferation and activation of lymphocytes were lower while they were incubated with plus-PEG grafts, compared with minus-PEG grafts and Optisol grafts. The mean survival time was significantly prolonged in plus-PEG grafts. DMEM/F12 solution plus mPEG-SPA improved the survival of corneal grafts and maintained the comparative biophysical characteristics of them, compared with the standard preservation solution. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate the effects of leptin/leptin receptor (LepR) combined with mechanical stress on the development of ossification of the posterior longitudinal ligament (OPLL), which is a disease characterized by ectopic bone formation of the posterior longitudinal ligament (PLL) and can lead to radiculopathy and myelopathy.Methods: Six human samples of the PLL were analyzed for the expression of leptin and LepR by RT-PCR and western blotting. PLL cells were stimulated with leptin and mechanical stress delivered via a Flexcell tension system, and osteogenic differentiation was evaluated by RT-PCR and western blotting analysis of osteogenic marker expression as well as by alkaline phosphatase (ALP) staining and alizarin red S staining. Activation of mitogen-activated protein kinase (MAPK), Janus kinase (JAK) 2-signal transducer, activator of transcription (STAT) 3 and phosphatidylinositol 3-kinase (PI3K)-Akt was evaluated by western blotting.Results: Samples from the OPLL group had higher LepR mRNA and protein levels and lower leptin levels than those from healthy controls. Exposure to leptin and Flexcell increased the number of ALP-positive cells and calcium nodules in a dose-dependent manner; this effect was accompanied by upregulation of the osteogenic markers osteocalcin, runt-related transcription factor 2 (RUNX2) and osteopontin. Extracellular signal-regulated kinase, P38 MAPK, JAK2, STAT3, PI3K and Akt signaling, was also activated by the combined effects of leptin and mechanical stress.Conclusions: Leptin and LepR are differentially expressed in OPLL tissues, and the combined use of leptin/LepR and mechanical stress promotes osteogenic differentiation of PLL cells via MAPK, JAK2-STAT3 and PI3K/Akt signaling. These slides can be retrieved under Electronic Supplementary Material. [ABSTRACT FROM AUTHOR]

A profound consideration of stable oxygen isotope source water origins is a precondition for an unambiguous palaeoenvironmental interpretation of terrestrial δ O archives. To stress the influence of air mass origins on widely used δ O tree-ring chronologies, we conducted correlation analyses between six annually resolved δ O tree-ring cellulose ( $\delta ^{18}\textit {O}_{TC}$ ) chronologies and mean annual air package origins obtained from backward trajectory modeling. This novel approach has been tested for a transect at the southeastern Tibetan plateau (TP), where air masses with different isotopic composition overlap. Detailed examinations of daily precipitation amounts and monthly precipitation δ O values ( $\delta ^{18}\textit {O}_{P}$ ) were conducted with the ERA Interim and Laboratoire de Météorologie Dynamique General Circulation Model (LMDZiso) data, respectively. Particularly the southernmost study sites are influenced by a distinct amount effect. Here, air package origin $\delta ^{18}\textit {O}_{TC}$ relations are generally weaker in contrast to our northern located study sites. We found that tree-ring isotope signatures at dry sites with less rain days per year tend to be influenced stronger by air mass origin than tree-ring isotope values at semi-humid sites. That implies that the local hydroclimate history inferred from $\delta ^{18}\textit {O}_{TC}$ archives is better recorded at semi-humid sites. [ABSTRACT FROM AUTHOR]

In contrast to a global retreating trend, glaciers in the Karakoram showed stability and/or mass gaining during the past decades. This 'Karakoram Anomaly' has been assumed to result from an out-of-phase temperature trend compared to hemispheric scales. However, the short instrumental observations from the Karakoram valley bottoms do not support a quantitative assessment of long-term temperature trends in this high mountain area. Here, we presented a new April-July temperature reconstruction from the Karakoram region in northern Pakistan based on a high elevation (~3600 m a.s.l.) tree-ring chronology covering the past 438 years (AD 1575-2012). The reconstruction passes all statistical calibration and validation tests and represents 49 % of the temperature variance recorded over the 1955-2012 instrumental period. It shows a substantial warming accounting to about 1.12 °C since the mid-twentieth century, and 1.94 °C since the mid-nineteenth century, and agrees well with the Northern Hemisphere temperature reconstructions. These findings provide evidence that the Karakoram temperatures are in-phase, rather than out-of-phase, compared to hemispheric scales since the AD 1575. The synchronous temperature trends imply that the anomalous glacier behavior reported from the Karakoram may need further explanations beyond basic regional thermal anomaly. [ABSTRACT FROM AUTHOR]

We present a newly developed, annually resolved tree-ring cellulose δO chronology for the southeastern Tibetan Plateau (TP) from Sikkim larch ( Larix griffithii), spanning between 1684 and 2012. Comparisons with local and regional climate data reveal strong positive correlations with monthly sunshine hours, temperature and daily temperature amplitude as well as strong negative correlations with relative humidity, vapor pressure, rain days per month and cloud cover of August. Relationships with local and regional tree-ring δO chronologies are stable and highly significant. Over the 20th century, we find no long-term climatic trends. This is consistent with other tree-ring δO chronologies of other tree species south of the Himalayas, but contrasts with results from isotope studies north of the Himalayas. This suggests stable macroclimatic flow patterns throughout the last centuries for the southern tree stands. In terms of large-scale climate dynamics, we find evidence of a significant 30-year wave influencing our tree-ring oxygen chronology, most probably induced by the Indian Ocean Dipole and influencing tree-ring oxygen isotope chronologies along the southeastern Himalaya and the southeastern rim of the TP. This pattern is spatially and temporarily consistent among the chronologies and has apparently strengthened during the last century. During periods of strong positive dipole mode activity, the dipole mode index shows positive correlations with the δO of tree-rings on the southeastern TP. [ABSTRACT FROM AUTHOR]

Exploration of high-rate lithium-ion batteries (LIBs) still remains a great challenge because of the ineffective charge transfer in electrode materials. In this work, the one-dimensional (1D)-2D coupled composites consisted of CoMoO nanorods and graphene sheets are developed as high-rate LIBs anode materials. The composites are well characterized with powder X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM), thermogravimetric analysis (TGA), and Raman spectrum. Endowed with the structural advantages, the present sample exhibits remarkably enhanced electrochemical properties, such as the best high-rate performance for CoMoO-based electrode materials so far (646 mAh g at 5 A g after 200 cycles), excellent rate capability, and stable cyclability. [ABSTRACT FROM AUTHOR]

Gastric cancer is the fourth most common malignancy in the world. Although microRNA-200 (miR-200) family members are thought to play roles in tumorigenesis, their functions in carcinogenesis are tumor specific, and the underlying mechanism of action still remains elusive. Few studies to date have addressed the dysregulation and function of miR-200 family members in gastric cancer progression. Here, we report that the miR-200 family members, miR-200c and miR-141, were significantly downregulated in gastric cancer specimens and gastric cancer cell lines. Importantly, on clinical samples, the expression of miR-200c and miR-141 was inversely correlated with TNM stage, tumor invasion depth (T), tumor embolus and disease-free survival. Wound-healing assay results showed that co-transfected miR-200c/141 could inhibit the migration and invasion capability of the gastric cell line SGC-7901. We also found that miR-200c and miR-141 directly targeted zinc finger E-box-binding homeobox 1/2 (ZEB1/2) and upregulated E-cadherin expression. In specimens from gastric cancer patients, reduced expression of miR-200c/141 was associated with increased expression of ZEB1 and/or ZEB2. In addition, the downregulation of miR-200c and miR-141 was found to be due to a highly methylated CpG island located upstream of their genomic sequence and/or upregulated TGF-β signaling. Treatment with the chemotherapeutic agent decitabine, a known DNA methyltransferase inhibitor, increased miR-200c/141 expression and ameliorated decreased expression of miR-200c/141 induced by TGF-β in SGC-7901 cells. Our study revealed that miR-200c/141 was downregulated by CpG island methylation and TGF-β signaling, which decreased ZEB1/2 expression and increased E-cadherin expression to inhibit migration and invasion of gastric cancer cells and provides powerful evidence for the application of decitabine in gastric cancer treatment. [ABSTRACT FROM AUTHOR]

The absence of tactile force information at the tip of a medical instrument makes precise minimally invasive surgery difficult and is prone to resulting in serious outcomes. In this paper, a fiber optic force sensor is fabricated based on Fabry-Pérot interferometry and integrated with a puncture needle. The force sensor is attached to the needle tip, where interactive force arises as it inserts into soft tissue. Needle insertion experiments have been conducted on ex vivo swine liver and belly with the calibrated force sensor. Using wavelet transform method, the acquired force data are analyzed and used to identify layered tissue types and boundaries. We found that the force amplitudes are not always identical, but the patterns of forces are almost the same, which enables us to identify layered tissues and to realize a safe needle insertion procedure under robot control. [ABSTRACT FROM AUTHOR]

Three-dimensional CoO-graphene frameworks (3D-CGFs) are prepared with a one-pot hydrothermal method. CoO particles are in situ anchored on graphene sheets, and the resulting composite self-assembles into 3D architecture during the hydrothermal treatment. Scanning electron microscope, transmission electron microscope, powder X-ray powder diffraction, and Raman spectroscopy are employed to characterize the sample. When tested as anode materials for lithium-ion batteries, 3D-CGFs demonstrate remarkable electrochemical lithium storage properties, such as large and stable reversible capacity (>530 mAh g at 500 mA g over 300 cycles), good capacity retention (88 % retention after 300 cycles at 500 mA g compared with the 4th cycle), excellent high-rate performance (515 mAh g at 1 A g), making it a promising candidate for high-performance anode materials, especially for high-rate lithium-ion batteries. [ABSTRACT FROM AUTHOR]

Fluctuation history of Midui glacier in the southeastern Tibet since the Little Ice Age (LIA) was reconstructed by the dating of lateral and terminal moraines using tree rings. Four conversions of glacier advance/stabilization to retreat were identified at around 1767, 1875, 1924 and 1964. The glacier reached its LIA maximum position at 1767. The fluctuations are consistent with those of other glaciers from the Tibetan Plateau, the Rockies and the Alps, suggesting high spatial coherency of glacier fluctuations in the Northern Hemisphere. Comparison with the summer temperature reconstruction in the southeastern Tibetan Plateau indicated that the Midui glacier fluctuation may be related to temperature variation on the centennial timescale. On the decadal scale, the fluctuation could correspond to cold/warm variation with an 8-year lag on average. [ABSTRACT FROM AUTHOR]

Based on tree-ring samples collected from Zaduo area in southern Qinghai Province, a 646-year ring-width series was established. Using response function, correlation function and partial correlation analysis we found that the ring-width series is sensitive most to May and June mean maximum air temperature at Zaduo meteorological stations and the correlation is significantly negative. Therefore, May--June mean maximum air temperature in Zaduo area since 1360 is reconstructed using this ring-width series. The regression equation was cross-validated in the calibration period of 1961--2005. The calibration equation can explain 59.8% of the total variance. Since high temperature could reinforce evapotranspiration and result in water stress, the high values are more reliable than the low values in the reconstructed series. By further analyzing upon the reconstructed series, it shows that on the inter-annual scale there are 6 periods with higher temperature: 1438--1455, 1572--1612, 1684--1700, 1730--1754, 1812--1829 and 1853--1886; while there are 5 periods with lower temperature: 1547--1571, 1701--1729, 1755--1777, 1830--1852 and 1887--1910. There is no significant rising of temperature in recent 50 years. By comparison with the rings-width series nearby which are also sensitive to the mean maximum air temperature and the mean maximum temperature reconstruction by ring-widths, it is found that the variation of inter-annual scale is fairly common in the region. [ABSTRACT FROM AUTHOR]

The climate of the past 1000 years is an important context for evaluating the recent climate warming. However, there are few 1000-year-long climate reconstructions with annual resolution in the Qinghai-Tibet Plateau. In this paper, a dendroclimatic analysis was conducted for the radial growth of Qilian juniper from the upper forest limit in Wulan, Qinghai Province. The results of correlation analysis between the tree-ring widths and the climate variables indicate that the growth of junipers at the upper forest limit is mainly limited by low temperatures of September, November and February of the pre-growth season, and July of the current growth season. There is no significant correlation between the tree-ring widths and precipitation. A mean temperature from the previous year's September to the current year's April was reconstructed for the Wulan area since A.D. 1000. The reconstruction can explain 40.8% of the instrumental variance in the calibration period (1 856-2002). The reconstruction shows that the 20th century is the warmest 100 years, and the 1990s is the warmest decade during the past 1000 years, while the coldest 100 years and decade occur at 1600-1699 and 1642-1651, respectively. The variations are verified well by the temperature reconstruction of the middle Qilian Mountain (QL) and the total organic carbon (TOC) in the Qinghai Lake sediments. The comparison of our reconstruction with the annual temperature reconstruction of extra-tropical Northern Hemisphere suggests that the climate of Wulan during the Medieval Warm Period is of obvious regional specialty, but there was a good response to the climate of hemispheric scales during the recent 400 years. [ABSTRACT FROM AUTHOR]