Aging Mongolian pine plantations face high risks of drought-induced growth decline:evidence from both individual tree and forest stand measurements

Discerning vulnerability differences among different aged trees to drought-driven growth decline or to mortality is critical to implement age-specific countermeasures for forest management in water-limited areas.An important species for afforestation in dry environments of northern China,Mongolian pine(Pinus sylvestris var.mongolica Litv.)has recently exhibited growth decline and dieback on many sites,particularly pronounced in old-growth plantations.However,changes in response to drought stress by this species with age as well as the underlying mechanisms are poorly understood.In this study,tree-ring data and remotely sensed vegetation data were combined to investigate variations in growth at individual tree and stand scales for young(9-13 years)and aging(35-52 years)plantations of Mongolian pine in a water-limited area of northern China.A recent decline in tree-ring width in the older plantation also had lower values in satellited-derived normalized difference vegetation indices and normalized difference water indices relative to the younger plantations.In addition,all measured growth-related metrics were strongly correlated with the self-calibrating Palmer drought severity index during the growing season in the older plantation.Sensitivity of growth to drought of the older plantation might be attributed to more severe hydraulic limitations,as reflected by their lower sapwood-and leaf-specific hydraulic conductivities.Our study presents a comprehensive view on changes of growth with age by integrating multiple methods and provides an explanation from the perspective of plant hydraulics for growth decline with age.The results indicate that old-growth Mongolian pine plantations in water-limited environments may face increased growth declines under the context of climate warming and drying.

Emerging roles of plasmacytoid dendritic cell crosstalk in tumor immunity

Plasmacytoid dendritic cells(pDCs)are a pioneer cell type that produces type I interferon(IFN-I)and promotes antiviral immune responses.However,they are tolerogenic and,when recruited to the tumor microenvironment(TME),play complex roles that have long been a research focus.The interactions between p DCs and other components of the TME,whether direct or indirect,can either promote or hinder tumor development;consequently,p DCs are an intriguing target for therapeutic intervention.This review provides a comprehensive overview of p DC crosstalk in the TME,including crosstalk with various cell types,biochemical factors,and microorganisms.An in-depth understanding of p DC crosstalk in TME should facilitate the development of novel p DC-based therapeutic methods.

Ultrathin, Lightweight, and Flexible CNT Buckypaper Enhanced Using MXenes for Electromagnetic Interference Shielding

Lightweight,flexibility,and low thickness are urgent requirements for next-generation high-performance electromagnetic interference(EMI)shielding materials for catering to the demand for smart and wearable electronic devices.Although several efforts have focused on constructing porous and flexible conductive films or aerogels,few studies have achieved a balance in terms of density,thickness,flexibility,and EMI shielding effectiveness(SE).Herein,an ultrathin,lightweight,and flexible carbon nanotube(CNT)buckypaper enhanced using MXenes(Ti3C2Tx)for high-performance EMI shielding is synthesized through a facile electrophoretic deposition process.The obtained Ti3C2Tx@CNT hybrid buckypaper exhibits an outstanding EMI SE of 60.5 dB in the X-band at 100μm.The hybrid buckypaper with an MXene content of 49.4 wt%exhibits an EMI SE of 50.4 dB in the X-band with a thickness of only 15μm,which is 105%higher than that of pristine CNT buckypaper.Furthermore,an average specific SE value of 5.7×10^(4) dB cm^(2) g^(−1) is exhibited in the 5-μm hybrid buckypaper.Thus,this assembly process proves promising for the construction of ultrathin,flexible,and high-performance EMI shielding films for application in electronic devices and wireless communications.

Direct Patterning of Carbon Nanotube via Stamp Contact Printing Process for Stretchable and Sensitive Sensing Devices

Flexible and wearable sensing devices have broad application prospects in bio-monitoring such as pulse measurement,motion detection and voice recognition.In recent years,many significant improvements had been made to enhance the sensor’s performance including sensitivity,flexibility and repeatability.However,it is still extremely complicated and difficult to prepare a patterned sensor directly on a flexible substrate.Herein,inspired by typography,a lowcost,environmentally friendly stamping method for the mass production of transparent conductive carbon nanotube(CNT)film is proposed.In this dry transfer strategy,a porous CNT block was used as both the seal and the ink;and Ecoflex film was served as an object substrate.Welldesigned CNT patterns can be easily fabricated on the polymer substrate by engraving the target pattern on the CNT seal before the stamping process.Moreover,the CNT film can be directly used to fabricate ultrathin(300μm)strain sensor.This strain sensor possesses high sensitivity with a gauge factor(GF)up to 9960 at 85%strain,high stretchability(>200%)and repeatability(>5000 cycles).It has been used to measure pulse signals and detect joint motion,suggesting promising application prospects in flexible and wearable electronic devices.

极小种群广东含笑野外资源现状

为掌握极小种群广东含笑(Michelia guangdongensis)的种质资源现状并评估其濒危等级,本文对广东含笑原生地——广东石门台国家级自然保护区及其邻近地区进行了系统的野外调查。结果表明:(1)目前发现广东含笑有4个野外分布区,其中广东石门台国家级自然保护区红珠岩段和英德上天堂为首次报道。(2)船底顶是广东含笑最集中的分布区,种群数量最多,约有1,100株;英德上天堂种群数量最少,只有20株。(3)依据IUCN全球物种濒危等级评估标准,广东含笑应当被评为濒危(EN,B1a+B2a)。

冰川细菌冷杆菌属的多样性研究进展

冰川作为地球主要的冰冻圈环境之一,蕴藏着丰富的低温微生物资源。1976年,Inoue&Komagata从南极分离出一株嗜冷细菌,直到1997年,以这株嗜冷菌为模式物种,建立了冷杆菌属(Cryobacterium),同时该菌株被命名为嗜冷冷杆菌(Cryobacterium psychrophilum)。冷杆菌属物种主要分布于南北极、青藏高原冻土、冰川等低温环境,但与冰川等环境中其他常见类群相比丰度较低,属于稀有类群。目前,该属已有15个有效描述种,其中包含严格的嗜冷菌,但不同种对温度的耐受性有差异,因此是研究低温环境细菌进化和物种形成的良好材料。该属菌株可产生β-类胡萝卜素、低温酶等生物活性物质。本文综述了冷杆菌属的分布、生物学特征;通过对GenBank中冷杆菌属纯培养菌株的全基因组序列进行平均核酸序列一致性(average nucleotide identity,ANI)计算和聚类分析,明确其精确的分类地位,评估了该类群物种多样性;并讨论了冷杆菌在食品加工、医药卫生所需的生物活性物质的应用潜力。

Experimental study of an anti-icing method over an airfoil based on pulsed dielectric barrier discharge plasma

Aircraft icing has long been a plague to aviation for its serious threat to flight safety. Even though lots of methods for anti-icing have been in use or studied for quite a long time, new methods are still in great demand for both civil and military aircraft. The current study in this paper uses widely used Dielectric Barrier Discharge（DBD） plasma actuation to anti-ice on a NACA0012 airfoil model with a chord length of 53.5 cm in a closed-circuit icing wind tunnel. An actuator was installed at the leading edge of the airfoil model, and actuated by a pulsed low-temperature plasma power source. The actuator has two types of layout, a striped electrode layout and a meshy electrode layout.The ice accretion process or anti-icing process was recorded by a CCD camera and an infrared camera. Instantaneous pictures and infrared contours show that both types of DBD plasma actuators have the ability for anti-ice under a freestream velocity of 90 m/s, a static temperature of -7℃,an Median Volume droplet Diameter（MVD） of 20 lm, and an Liquid Water Content（LWC） of 0.5 g/m^3. The detected variations of temperatures with time at specific locations reveal that the temperatures oscillate for some time after spraying at first, and then tend to be nearly constant values.This shows that the key point of the anti-icing mechanism with DBD plasma actuation is to achieve a thermal equilibrium on the model surface. Besides, the power consumption in the anti-icing process was estimated in this paper by Lissajous figures measured by an oscilloscope, and it is lower than those of existing anti-icing methods. The experimental results presented in this paper indicate that the DBD plasma anti-icing method is a promising technique in the future.

nterferon alpha （IFNα）-induced TRIM22 interrupts HCV ＇eplication by ubiquitinating NS5A

TRIM22, a tripartite-motif （TRIM） protein, is upregulated upon interferon alpha （IFNa） administration to hepatitis C virus （HCV）-infected patients. However, the physiological role of TRIM22 upregulation remains unclear. Here, we describe a potential antiviral function of TRI M22＇s targeting of the HCV NSSA protein. NS5A is important for HCV replication and for resistance to I FNa therapy. During the first 24 h following the initiation of I FNa treatment, upregulation of TRIM22 in the peripheral blood mononuclear cells （PBMCs） of HCV patients correlated with a decrease in viral titer. This phenomenon was confirmed in the hepatocyte-derived cell line Huh-7, which is highly permissive for HCV infection. TRIM22 over-expression inhibited HCV replication, and Small interfering RNA （siRNA）-mediated knockdown of TRIM22 diminished IFNα-induced anti-HCV function. Furthermore, we determined that TRIM22 ubiquitinates NS5A in a concentration-dependent manner. In summary, our results suggest that TRIM22 upregulation is associated with HCV decline during IFNα treatment and Dlavs an important role in controlling HCV replication in vitro.

基于马兰戈尼效应制备具有周期性褶皱结构的石墨烯薄膜及其在高灵敏应变探测中的应用

石墨烯薄膜中可控的微纳结构,有利于调控其物理性质并拓宽其在柔性电子器件中的应用.近年来,研究人员致力于控制石墨烯薄膜中褶皱、起伏波纹等微纳结构的形成.但是,在石墨烯薄膜中可控地形成有序的褶皱状结构仍然面临巨大挑战.本文报道了一种简单地制备具有周期性平行褶皱结构的石墨烯薄膜的方法,即通过将溶液表面自组装形成的石墨烯薄膜转移至预拉伸的聚二甲基硅氧烷(PDMS)基底上而得到.制备的石墨烯薄膜中,褶皱的宽度可以简单地通过改变基底的预拉伸形变来控制.当PDMS基底预拉伸应变分别为10%、20%和50%时,薄膜中褶皱的平均宽度分别为3.68、2.99和2.01µm.本文还进一步研究和分析了双层堆叠、褶皱状石墨烯薄膜,在拉伸形变时的形貌结构变化.此外,本文基于该褶皱状石墨烯薄膜,构建了应变传感器.该传感器展现出高灵敏度、宽探测范围和优良的循环稳定性,其在实时运动探测、健康监测和电子皮肤等领域有着广阔应用前景.

Engineering prodrug nanomicelles as pyroptosis inducer for codelivery of PI3K/mTOR and CDK inhibitors to enhance antitumor immunity

Aberrant activation of oncogenic signaling pathways in tumors can promote resistance to the antitumor immune response.However,single blockade of these pathways is usually ineffective because of the complex crosstalk and feedback among oncogenic signaling pathways.The enhanced toxicity of free small molecule inhibitor combinations is considered an insurmountable barrier to their clinical applications.To circumvent this issue,we rationally designed an effective tumor microenvironment-activatable prodrug nanomicelle(PNM)for cancer therapy.PNM was engineered by integrating the PI3K/m TOR inhibitor PF-04691502(PF)and the broad spectrum CDK inhibitor flavopiridol(Flav)into a single nanoplatform,which showed tumor-specific accumulation,activation and deep penetration in response to the high glutathione(GSH)tumoral microenvironment.The codelivery of PF and Flav could trigger gasdermin E(GSDME)-based immunogenic pyroptosis of tumor cells to elicit a robust antitumor immune response.Furthermore,the combination of PNM-induced immunogenic pyroptosis with antiprogrammed cell death-1(a PD-1)immunotherapy further boosted the antitumor effect and prolonged the survival time of mice.Collectively,these results indicated that the pyroptosis-induced nanoplatform codelivery of PI3K/m TOR and CDK inhibitors can reprogram the immunosuppressive tumor microenvironment and efficiently improve checkpoint blockade cancer immunotherapy.

Inspired heat shock protein alleviating prodrug enforces immunogenic photodynamic therapy by eliciting pyroptosis

Despite immunotherapy involving immune checkpoint inhibitors(ICIs)have revolutionized cancer therapy,the clinical efficacy is limited due to ICI resistance.Pyroptosis is a gasdermin-mediated programmed cell death that enhances responses to ICIs.However,nontargeted elicitation of pyroptosis may induce systemic side effects and toxicity.Therefore,we reasonably design and construct a tumor-specific prodrug that combines the heat shock protein 90 inhibitor tanespimycin(17-AAG)with the photosensitizer chlorin e6(Ce6)to induce pyroptosis,by utilizing the high glutathione level in the tumor microenvironment.The released Ce6 and 17-AAG produce reactive oxygen species by laser triggering,which induces gasdermin E-mediated pyroptosis.Furthermore,17-AAG reduces myeloid-derived suppressor cells and sensitizes tumors to anti-programmed death^(-1)(PD-1)therapy.Thus,our prodrug strategy achieves tumor-targeted pyroptosis to suppress tumor growth,thereby improving the response to anti-PD-1 therapy and extending the survival of 4T1 breast tumor-bearing mice.Consequently,this pyroptosis-based prodrug represents a novel strategy for enforcing immunogenic photodynamic therapy.

Controlling sulfurization of 2D Mo_(2)C crystal for Mo_(2)C/MoS_(2)-based memristor and artificial synapse

Owing to the conductance-adjustable performance,the emerging two-terminal memristors are promising candidates for artificial synapses and brain-spired neuromorphic computing.Although memristors based on molybdenum disulfide(MoS_(2))have displayed outstanding performance,such as thermal stability and high energy efficiency,reports on memristors based on MoS_(2) as the functional layer to simulate synaptic behavior are limited.Herein,a homologous Mo_(2)C/MoS_(2)-based memristor is prepared by partially sulfuring two-dimensional Mo_(2)C crystal.The memristor shows good stability,excellent retention(~104 s)and endurance(>100 cycles),and a high ON/OFF ratio(>10^(3)).Moreover,for comprehensively mimicking biological synapses,the essential synaptic functions of the device are systematically analyzed,including paired-pulse facilitation(PPF),short-term plasticity(STP),long-term plasticity(LTP),long-term depression(LTD),and the transitions from STP to LTP.Notably,this artificial synapse could keep a highlevel stable memory for a long time(60 s)after repeated stimulation.These results prove that our device is highly desirable for biological synapses,which show great potential for application in future high-density storage and neuromorphic computing systems.

Reduced phosphatidylcholine synthesis suppresses the embryonic lethality of seipin deficiency

Seipin plays a vital role in lipid droplet homeostasis,and its deficiency causes congenital generalized lipodystrophy type II in humans.It is not known whether the physiological defects are all caused by cellular lipid droplet defects.Loss-of-function mutation of seip-1,the Caenorhabditis elegans seipin ortholog,causes embryonic lethality and lipid droplet abnormality.We uncover nhr-114 and spin-4 as two suppressors of seip-1 embryonic lethality.Mechanistically,nhr-114 and spin-4 act in the“B12-one-carbon cycle-phosphatidylcholine(PC)”axis,and reducing PC synthesis suppresses the embryonic lethality of seip-1 mutants.Conversely,PC deficiency enhances the lipid droplet abnormality of seip-1 mutants.The suppression of seip-1 embryonic lethality by PC reduction requires polyunsaturated fatty acid.In addition,the suppression is enhanced by the knockdown of phospholipid scramblase epg-3.Therefore,seipin and PC exhibit opposite actions in embryogenesis,while they function similarly in lipid droplet homeostasis.Our results demonstrate that seipin-mediated embryogenesis is independent of lipid droplet homeostasis.