二硫化钼在电子束辐照下的缺陷结构演变及其物理机制研究进展

二硫化钼(MoS_(2))丰富的多原子结构赋予了它优异的电学、光学、催化等性能,这引起了人们的极大兴趣。而MoS_(2)中存在的缺陷结构往往会对其性能产生显著的影响,通常认为这种影响是负面的,因此以往的研究几乎都是在尽量避免缺陷结构的产生。但是最近也有一些研究表明MoS_(2)缺陷的存在对其应用起到了积极作用。为了能够更好地利用MoS_(2)的缺陷结构,使其产生积极影响,首先需要了解这些缺陷结构,弄清楚它们的演变方式和相关物理机制,并用来指导MoS_(2)的可控纳米加工和实际应用。本文总结了MoS_(2)不同类型的缺陷结构以及在电子束辐照下MoS_(2)的结构演变行为,从中探究电子束与MoS_(2)缺陷结构交互作用的机理。通过分析传统物理机制的不足,提出了两个全新的概念——纳米曲率效应和电子束非热激活效应,分别从纳米空间限制角度和超快时间限制角度来挖掘这些实验现象背后的深层物理机制。最后,本文还提出了对MoS_(2)缺陷结构调制与纳米可控加工的看法和展望。

不同湿度下番茄潜夜蛾的年龄-龄期两性生命表

【目的】明确湿度变化对番茄潜夜蛾Tuta absoluta生长发育和繁殖的影响。【方法】在室内相对湿度15%,35%,55%,75%和95%下测定番茄潜夜蛾发育历期、产卵前期、世代周期、幼虫存活率、成虫存活率和单雌产卵量等,制定其年龄-龄期两性生命表,利用年龄-龄期两性生命表计算其种群存活率、繁殖力、寿命期望值、繁殖值等种群参数。【结果】在相对湿度15%~95%范围内,相对湿度15%和95%下番茄潜夜蛾卵历期均显著长于相对湿度35%,55%和75%下的;4龄幼虫期随相对湿度升高先缩短后延长;雄成虫寿命随相对湿度升高而增加,相对湿度95%时雄成虫历期最长;雌成虫寿命在相对湿度75%时达到最大值;相对湿度95%下世代周期显著长于其他相对湿度下的;单雌产卵量随相对湿度升高而增加。相对湿度影响了雌成虫初产卵时间,相对湿度15%,35%,55%,75%和95%下其初产卵时间分别为31,27,27,27和31 d;种群年龄-特征净繁殖率和年龄-龄期-特征繁殖值均随相对湿度升高而增加,在95%时达最大值;内禀增长率和周限增长率随相对湿度升高先增后降,净增殖率随相对湿度升高而增加,平均世代周期随相对湿度升高先减后增。根据种群生命表参数预测未来60 d内种群动态结果表明,相对湿度95%条件下有利于番茄潜叶蛾种群数量的增加,相对湿度15%和95%度条件不利于种群世代的增加。通过线性拟合,不同相对湿度对卵和幼虫的存活率影响显著。【结论】实验设置相对湿度范围内,番茄潜夜蛾生长发育最适相对湿度为55%和75%,繁殖最适宜相对湿度为95%。

Risk of cardiovascular death in patients with hepatocellular carcinoma based on the Fine-Gray model

BACKGROUND Hepatocellular carcinoma(HCC)is one of the most common types of cancers worldwide,ranking fifth among men and seventh among women,resulting in more than 7 million deaths annually.With the development of medical tech-nology,the 5-year survival rate of HCC patients can be increased to 70%.How-ever,HCC patients are often at increased risk of cardiovascular disease(CVD)death due to exposure to potentially cardiotoxic treatments compared with non-HCC patients.Moreover,CVD and cancer have become major disease burdens worldwide.Thus,further research is needed to lessen the risk of CVD death in HCC patient survivors.METHODS This study was conducted on the basis of the Surveillance,Epidemiology,and End Results database and included HCC patients with a diagnosis period from 2010 to 2015.The independent risk factors were identified using the Fine-Gray model.A nomograph was constructed to predict the CVM in HCC patients.The nomograph performance was measured using Harrell’s concordance index(C-index),calibration curve,receiver operating characteristic(ROC)curve,and area under the ROC curve(AUC)value.Moreover,the net benefit was estimated via decision curve analysis(DCA).RESULTS The study included 21545 HCC patients,of whom 619 died of CVD.Age(<60)[1.981(1.573-2.496),P<0.001],marital status(married)[unmarried:1.370(1.076-1.745),P=0.011],alpha fetoprotein(normal)[0.778(0.640-0.946),P=0.012],tumor size(≤2 cm)[(2,5]cm:1.420(1.060-1.903),P=0.019;>5 cm:2.090(1.543-2.830),P<0.001],surgery(no)[0.376(0.297-0.476),P<0.001],and chemotherapy(none/unknown)[0.578(0.472-0.709),P<0.001]were independent risk factors for CVD death in HCC patients.The discrimination and calibration of the nomograph were better.The C-index values for the training and validation sets were 0.736 and 0.665,respectively.The AUC values of the ROC curves at 2,4,and 6 years were 0.702,0.725,0.740 in the training set and 0.697,0.710,0.744 in the validation set,respectively.The calibration curves showed that the predicted probab-ilities of the CVM prediction model in the training set vs the validation set were largely consistent with the actual probabilities.DCA demonstrated that the prediction model has a high net benefit.CONCLUSION Risk factors for CVD death in HCC patients were investigated for the first time.The nomograph served as an important reference tool for relevant clinical management decisions.

Evaluating correlation between the ocular biometry and genetic variants of MYOC and ABCA1 with primary angleclosure glaucoma in a cohort from northern China

AIM: To investigate whether the gene variants in MYOC and ABCA1 are associated with primary angle-closure glaucoma(PACG) and anterior chamber depth(ACD) and axial length(AL) in samples from northern China. METHODS: The present case-control association study consisted of 500 PACG patients and 720 unrelated controls. Each participant was genotyped for eleven single nucleotide polymorphisms(SNPs) in MYOC and ABCA1 genes(rs12076134, rs183532, rs235875 and rs235913 in MYOC, rs2422493, rs2487042, rs2472496, rs2472493, rs2487032, rs2472459 and rs2472519 near ABCA1) using an improved multiplex ligation detection reaction(iMLDR) technique. The genetic association analyses were performed by PLINK using a logistic regression model. The association between genotypes and ocular biometric parameters was performed by SPSS using generalized estimation equation. Bonferroni corrections wereimplemented and the statistical power was calculated by the Power and Sample Size Calculation. RESULTS: Two SNPs rs183532 and rs235875 as well as a haplotype TTC in MYOC were nominally associated with PACG despite the significance was lost after Bonferroni correction. No association was observed between ABCA1 and PACG, neither did the association between these variants and ACD as well as AL. CONCLUSION: The present study suggests MYOC and ABCA1 do not play a part in the pathogenesis of PACG as well as the regulation of ocular biometric parameters in a northern Chinese population. Further investigations with large sample size are needed to verify this consequence.

菜粉蝶成虫触角转录组及嗅觉相关基因分析

【目的】建立菜粉蝶Pieris rapae成虫触角转录组数据库,利用生物信息学和分子生物学手段深入挖掘菜粉蝶基因数据信息。【方法】采用高通量测序平台(Illumina NovaSeq 6000)对菜粉蝶成虫触角进行转录组测序、序列组装、功能注释及差异表达基因分析,对PrapOR1,PrapOR2,PrapOR5,PrapOBP1,PrapOBP4,PrapOBP5,PrapSNMP1,PrapSNMP2和PrapSNMP39个差异表达的嗅觉相关基因进行qRT-PCR验证。【结果】菜粉蝶成虫触角转录组共获得17.65 GB测序数据(NCBI登录号:PRJNA869896),经过滤和序列拼接共得到116317条转录本,随后进行Corset层次聚类获得43390条unigene,经BUSCO评估,拼接质量完整度好,准确性高。注释到的unigene数目从大到小排列的数据库依次为NT,NR,Pfam,GO,Swiss-Prot,KEGG和KOG/COG;进一步进行基因功能注释分析,筛选得到176个嗅觉相关基因,其中19个基因差异表达,包括在雌成虫触角中高表达的15个基因和在雄成虫触角中高表达的4个基因。qRT-PCR验证结果表明,PrapOR1和PrapOR2在雄成虫触角中高表达,PrapOR5,PrapOBP1,PrapOBP4,PrapOBP5,PrapSNMP1,PrapSNMP2和PrapSNMP3在雌成虫触角中高表达,与转录组测序结果相符。【结论】本研究建立了菜粉蝶成虫触角转录组数据库,筛选得到了嗅觉相关基因,并对嗅觉相关基因进行了差异表达分析,研究结果为进一步研究菜粉蝶的基因功能及嗅觉分子机制奠定了理论基础。

菜粉蝶幼虫、蛹和成虫的雌雄形态鉴别

利用体视显微镜观察、测量、记录菜粉蝶不同虫态雌雄个体间的形态特征差异。雌雄菜粉蝶幼虫、蛹和成虫均存在显著的雌雄二型特征,3龄之后雄性幼虫的第6腹节有一对肾型黑斑,雌性幼虫无此斑。雄蛹第9腹节有生殖孔和一条短纵裂缝,裂缝两侧有凹凸不平的半圆形瘤状突起;雌蛹腹部第8、9腹节分别有生殖孔和产卵孔,且两孔之间亦有一条纵裂缝。雌蝶前翅背面有一对上下排列的黑圆斑,其腹部末端外生殖器为圆筒型;雄蝶前翅背面一对黑斑相对较小,颜色较浅,尤其下斑为浅灰色,腹部末端具钳状外生殖器。本研究揭示了菜粉蝶幼虫、蛹及成虫不同虫态的雌雄二型差异,比较研究并提出了便于快速鉴别雌雄个体的典型特征和识别方法。

甘蓝挥发物对小菜蛾幼虫取食行为的影响

[目的]明确寄主植物甘蓝(Brassica oleracea L.)挥发物对小菜蛾(Plutella xylostella)幼虫取食行为反应的影响,为筛选小菜蛾植物源引诱剂提供理论依据。[方法]利用Y型嗅觉仪测定小菜蛾幼虫雌雄虫对甘蓝3种活性挥发物的嗅觉反应,通过田间试验测定在挥发物存在下小菜蛾幼虫对花椰菜植株的取食效果。[结果]甘蓝3种挥发物能够引起小菜蛾幼虫嗅觉反应,但不同浓度下引诱选择率不同。异硫氰酸烯丙酯浓度为1μg·μL;时对雌雄小菜蛾幼虫均表现出极显著引诱效果,引诱率分别为75%和80%;浓度为10μg·μL;的异硫氰酸丁酯对雌、雄幼虫的引诱率分别为75%和80%;顺-3-己烯醇对幼虫雄虫引诱率为70%;在田间取食试验中,3种化合物总体上可以促进小菜蛾幼虫取食,取食指数均显著高于对照,然而浓度为500μg·μL;的异硫氰酸烯丙酯则对雄性幼虫表现出拒食效果。[结论]异硫氰酸烯丙酯、异硫氰酸丁酯和顺-3-己烯醇对小菜蛾幼虫具有较强的引诱作用,这些可为治理小菜蛾为害十字花科植物提供新的思路和方法。

Effects of Various Degrees of Antennal Ablation on Mating and Oviposition Preferences of the Diamondback Moth,Plutella xylostella L.

Using scanning electron microscopy, we investigated the distribution of the trichoid, basiconic, and coeloconic sensilla on the antennae of the diamondback moth （DBM;Plutella xylostella）. The trichoid sensilla were the most abundant sensory organ, and the male moth antennae host signiifcantly more trichoid sensilla than female moth antennae. Conversely, basiconic and coeloconic sensilla were found more frequently on female than on male antennae. We performed experiments with various degrees of antennal ablation and demonstrated that DBM antennae played a key role in the control of mating and oviposition. We found that neither oviposition preference nor mating behaviors changed signiifcantly when less than 1/4 of both antennae were removed. However, there was a signiifcant behavioral change when the antennae were ablated by more than half. As the length of the antenna was shortened, the successful mating rate decreased and mating peak was delayed. An otherwise consistent host preference for oviposition was eliminated when both antennae were completely removed. Furthermore, we found that the number of trichoid sensilla was positively correlated with mating rate and oviposition preference. However, the numbers of basiconic and coeloconic sensilla were not correlated with mating rate and mating peak, but highly correlated with oviposition preference. Taken together, our results indicate that antennal sensory information plays a critical role in the mating and oviposition behaviors of this economically important pest.

小菜蛾成虫对几种甜味和苦味物质的味觉反应

昆虫味觉在其产卵和寄主选择过程中发挥着重要作用,为了明确小菜蛾对常见植物非挥发物的敏感性,为深入研究小菜蛾成虫取食机制提供行为上的依据,也为寻找新型防治害虫的方法提供新思路,采用喙管伸长反应,通过刺激小菜蛾触角末端研究了小菜蛾对蔗糖、葡萄糖、海藻糖、麦芽糖和果糖等5种不同浓度的甜味物质以及奎宁、苯甲地那铵、黄连素等3种低浓度苦味物质的味觉反应。结果表明,100 mmol/L的5种糖均可刺激小菜蛾雌、雄成虫产生喙管伸长反应,其中,雌性小菜蛾对蔗糖的反应最强,反应率达57.5%,对果糖最弱,反应率仅为20%;雄性小菜蛾同样对蔗糖的反应最强,对麦芽糖的反应最弱;雌性小菜蛾对甜味物质的味觉反应显著强于雄性小菜蛾;对糖类物质的伸喙反应率随着浓度增大而增大,蔗糖浓度为500 mmol/L时引起反应最强,反应率达60%。低浓度的奎宁、苯甲地那铵和黄连素抑制了雌性小菜蛾的喙管伸长反应,降低其对甜味物质的味觉反应。

Single-cell transcriptome analysis reveals a cancer-associated fibroblast marker gene signature in hepatocellular carcinoma that predicts prognosis

Background and aims:Hepatocellular carcinoma(HCC)is one of the leading causes of cancer death.Multi-pathway combination therapy is used to treat HCC,and immunotherapy is also a routine part of treatment.As a major component of the tumor microenvironment(TME),cancer-associated fibroblasts(CAFs)actively participate in cancer progression through complex functions.However,because CAFs dynamically change during cancer development,most of the current treatment strategies targeting CAFs fail.We created a prognostic CAF marker gene signature(CAFMGS)to investigate the utility of CAFs as a prognostic factor and therapeutic target.Methods:Gene Expression Omnibus(GEO)single-cell RNA sequencing(Sc-RNA-seq)data were analyzed to identify CAF marker genes in HCC.The Cancer Genome Atlas(TCGA)database was used as a training cohort to construct the CAFMGS model and the International Cancer Genome Consortium(ICGC)dataset was used to validate the CAFMGS.Results:Marker genes in the CAFMGS model were(0.0001-SPP1),(0.0084-VCX3A),(0.0015-HMGA1),(0.0082-PLOD2),and(0.0075-CACYBP).The CAFMGS_score was separated into high-risk and low-risk groups based on the median of the patients’OS.Univariate and multivariate analyses confirmed that CAFMGS_score was an independent prognostic factor in the training group.CAFMGS_score was a more accurate prognostic indicator compared with clinicopathological score and tumor mutational burden score.Conclusion:CAFMGS offers a fresh perspective on stromal cell marker genes in HCC prognosis and expands our knowledge of CAF heterogeneity and functional diversity,perhaps paving the way for CAF-targeted immunotherapy in HCC patients.

梨小食心虫幼虫寄主选择性和主要感器

【目的】明确梨小食心虫Grapholithamolesta(Busck)幼虫的寄主选择能力和主要感器。【方法】在室内条件下,测定梨小食心虫幼虫在7种寄主果实、不同发育阶段果实及受损伤果实的上的数量,并测定3种感器单独、两两组合处理及3种感器全部处理后的幼虫在不同寄主果实上的数量。【结果】1龄时,选择丰白毛桃、红富士苹果和霞光油桃的幼虫数分别为12.00、8.67和9.00头,选择早酥梨、嘎啦苹果和皇冠梨的幼虫数为2.00、1.00、1.00头;5龄时,选择上述6种果实的幼虫数依次为8.67、7.00、6.00、5.33、4.00和3.67头。选择丰白毛桃、红富士苹果和霞光油桃成熟期果实的幼虫数均显著高于选择同种未成熟和成熟早期果实。选择受损伤丰白毛桃、红富士苹果和霞光油桃的幼虫数显著高于选择同种未受损伤果实。分别单独处理触角、下颚须+下唇须和胸足的幼虫,未选择寄主果实的幼虫数为7.33-10.00头;两两感器组合处理后,未选择的幼虫数与单独处理触角无显著差异;3种感器全部处理的幼虫无选择能力,未选择的幼虫数为17.67头。【结论】梨小食心虫幼虫可选择寄主,且对寄主的选择性随幼虫龄期增加而变化。梨小食心虫幼虫触角是其选择寄主果实的主要感器。

小菜蛾成虫对健康和机械损伤薄荷的嗅觉反应

【目的】比较健康和机械损伤的薄荷Mentha spicata对小菜蛾Plutella xylostella成虫嗅觉反应的影响,为筛选小菜蛾植物源驱避剂提供科学依据。【方法】利用触角电位(EAG)仪和Y型嗅觉仪分别测定小菜蛾雌、雄成虫对健康和机械损伤薄荷的触角电位和嗅觉行为反应,通过田间试验测定雌蛾产卵选择的忌避反应。【结果】健康薄荷和机械损伤薄荷均能引起小菜蛾雌、雄成虫触角电位反应,但损伤薄荷引起的触角电位反应值显著高于健康薄荷(P<0.05);室内行为选择试验结果显示,损伤薄荷对小菜蛾雄性成虫有显著驱避作用(P<0.05),驱避指数为53.33%,对雌性成虫有极显著驱避作用(P<0.01),驱避指数达到80%;田间产卵选择试验发现,损伤薄荷对小菜蛾雌成虫产卵有极显著驱避作用(P<0.01),产卵忌避指数达到71.32%。但是健康薄荷对小菜蛾雌、雄成虫的行为选择和雌性成虫的产卵选择均无显著驱避作用(P>0.05)。【结论】机械损伤薄荷对小菜蛾成虫有较强的驱避效果,可以对其进行驱避活性挥发物质的筛选或作为驱避源来防治小菜蛾的危害。

De novo identification and quantification of single amino-acid variants in human brain

单个氨基酸的变体(SAV ) 的察觉通常取决于单个核苷酸的多型性(SNP ) 数据库。这里，我们描述发现在 proteome 的 SAV 铺平 SNP 数据的独立人士的一个新奇方法。用定序算法的集体基于 spectrometry 的 de novo，肽候选人被识别并且与理论蛋白质数据库到相比在配对策略下面产生 SAV，它被数据库研究到控制跟随假发现率。在人的大脑纸巾，我们能充满信心地识别知道并且有多样的起源的新奇蛋白质变体。与 DNA/RNA 定序结合了，我们证实 SAV 源于 DNA 变化，拼接的 RNA 选择，和未知 post-transcriptional 机制。而且，在人的大脑纸巾的定量分析揭示 SAV 的几织物特定的微分表情。这条途径提供新奇存取给蛋白质变体的高产量的察觉，它可以为临床的 biomarker 发现和机械学的研究提供潜力。

MXene-Ti3C2Tx for watt-level high-efficiency pulse generation in a 2.8μm mid-infrared fiber laser

We report a watt-level passively Q switched 2.8μm mid-infrared multi-mode fiber laser by employing multi-layered two dimensional MXene-Ti3C2Tx as the saturable absorber(SA).The MXene-Ti3C2Tx is fabricated by selectively etching aluminum layers in Ti3AlC2.The non-saturable loss,modulation depth,and saturable inten-sity of the SA at 2866 nm were measured to be 25.0%,33.2%,and 0.043 GW/cm^2,respectively.The maximum average output power of the Ti3C2Tx Q-switched fiber laser reached 1.09 W at 28.23%slope fficiency.The pulse repetition rate,shortest pulse width,pulse peak power,and single-pulse energy were 78.12 kHz,1.04μs,13.4 W,and 13.93μJ,respectively.This is the frst demonstration of watt-level pulse gencration in a mid-infrared fiber laser using low dimensional materials,to the best of our knowledge.These results indicate that the Ti3C2Tx is a reliable and superior broadband SA for high power mid-infrared pulsed laser generation.

Generation and propagation characteristics of electromagnetic vortices in radio frequency

Electromagnetic vortices, which describe the orbital angular momentum(OAM) carrying waves with a helical phase front, have recently attracted much interest in a radio frequency domain due to their potential applications in many diverse areas. In an OAM-based scenario, the antenna for OAM mode multiplexing/demultiplexing plays an essential role in controlling the overall system performance. In this paper, we demonstrated theoretically and experimentally an easily realized OAM antenna based on the traveling-wave circular loop structure for efficiently multiplexing/demultiplexing multiple OAM modes; in addition, its general propagation characteristics including the polarization, divergence, and radiation pattern are mathematically analyzed. Schemes for antenna size reduction and various radiation pattern manipulations have also been discussed to realize a more flexible and compact system.

Spurious-free dynamic range improvement in a photonic time-stretched analog-to-digital converter based on third-order predistortion

Spurious-free dynamic range(SFDR)limited by intermodulation distortions is a usually accepted measure for dynamic performance of a photonic time-stretched analog-to-digital converter(ADC).In this paper,SFDR improvement in a photonic time-stretched ADC based on third-order predistortion is proposed.The third-order predistortion is achieved optically within an integrated dual-parallel Mach–Zehnder modulator(DPMZM).The mechanism of SFDR improvement with third-order predistortion in the DPMZM is theoretically analyzed.Compared with a conventional scheme without predistortion,the experimental results show that the SFDR improvement of∼26 dB in the proposed scheme is proved.

不同温度下中国梨木虱的两性生命表

【目的】明确温度对中国梨木虱Psylla chinensis生长发育和繁殖的影响。【方法】室内条件下,16、20、24、28、32和36℃分别测定中国梨木虱各阶段发育历期、产卵量和存活率等,制定其年龄-龄期两性生命表,利用两性生命表计算其存活率、繁殖力、寿命期望、繁殖值和种群参数。【结果】16-24℃,中国梨木虱随温度升高,其生长速度加快、发育历期缩短;24-32℃其发育历期变化不显著;36℃条件下不能完成整个生长发育。24℃时产卵量最高,为281.50粒/雌。16-24℃,中国梨木虱的年龄特征存活率、种群特定年龄净繁殖力、平均贡献度均随温度升高而增加,24-32℃,均随温度升高而下降。24℃处理的内禀增长率、周限增长率和净增值率均最高,28℃处理的平均世代周期最短。【结论】结果表明中国梨木虱生长发育和繁殖适宜温度为24-28℃。