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Evolutionary history shapes variation of wood density of tree species across the world 被引量:1
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作者 Fangbing Li Hong Qian +7 位作者 Jordi Sardans Dzhamal Y.Amishev zixuan wang Changyue Zhang Tonggui Wu Xiaoniu Xu Xiao Tao Xingzhao Huang 《Plant Diversity》 SCIE CAS CSCD 2024年第3期283-293,共11页
The effect of evolutionary history on wood density variation may play an important role in shaping variation in wood density,but this has largely not been tested.Using a comprehensive global dataset including 27,297 m... The effect of evolutionary history on wood density variation may play an important role in shaping variation in wood density,but this has largely not been tested.Using a comprehensive global dataset including 27,297 measurements of wood density from 2621 tree species worldwide,we test the hypothesis that the legacy of evolutionary history plays an important role in driving the variation of wood density among tree species.We assessed phylogenetic signal in different taxonomic(e.g.,angiosperms and gymnosperms)and ecological(e.g.,tropical,temperate,and boreal)groups of tree species,explored the biogeographical and phylogenetic patterns of wood density,and quantified the relative importance of current environmental factors(e.g.,climatic and soil variables)and evolutionary history(i.e.,phylogenetic relatedness among species and lineages)in driving global wood density variation.We found that wood density displayed a significant phylogenetic signal.Wood density differed among different biomes and climatic zones,with higher mean values of wood density in relatively drier regions(highest in subtropical desert).Our study revealed that at a global scale,for angiosperms and gymnosperms combined,phylogeny and species(representing the variance explained by taxonomy and not direct explained by long-term evolution process)explained 84.3%and 7.7%of total wood density variation,respectively,whereas current environment explained 2.7%of total wood density variation when phylogeny and species were taken into account.When angiosperms and gymnosperms were considered separately,the three proportions of explained variation are,respectively,84.2%,7.5%and 6.7%for angiosperms,and 45.7%,21.3%and 18.6%for gymnosperms.Our study shows that evolutionary history outpaced current environmental factors in shaping global variation in wood density. 展开更多
关键词 Wood density PHYLOGENY ANGIOSPERMS GYMNOSPERMS Climate factors Biophysical parameters
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Fine-tuning the activation behaviors of ternary modular cabazitaxel prodrugs for efficient and on-target oral anti-cancer therapy
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作者 Mingyang Zhang Yifan Miao +7 位作者 Can Zhao Tong Liu Xiyan wang zixuan wang Wenxin Zhong Zhonggui He Chutong Tian Jin Sun 《Asian Journal of Pharmaceutical Sciences》 SCIE CAS 2024年第2期188-203,共16页
The disulfide bond plays a crucial role in the design of anti-tumor prodrugs due to its exceptional tumor-specific redox responsiveness. However, premature breaking of disulfide bonds is triggered by small amounts of ... The disulfide bond plays a crucial role in the design of anti-tumor prodrugs due to its exceptional tumor-specific redox responsiveness. However, premature breaking of disulfide bonds is triggered by small amounts of reducing substances (e.g., ascorbic acid, glutathione, uric acid and tea polyphenols) in the systemic circulation. This may lead to toxicity, particularly in oral prodrugs that require more frequent and high-dose treatments. Fine-tuning the activation kinetics of these prodrugs is a promising prospect for more efficient on-target cancer therapies. In this study, disulfide, steric disulfide, and ester bonds were used to bridge cabazitaxel (CTX) to an intestinal lymph vessel-directed triglyceride (TG) module. Then, synthetic prodrugs were efficiently incorporated into self-nanoemulsifying drug delivery system (corn oil and Maisine CC were used as the oil phase and Cremophor EL as the surfactant). All three prodrugs had excellent gastric stability and intestinal permeability. The oral bioavailability of the disulfide bond-based prodrugs (CTX-(C)S-(C)S-TG and CTX-S-S-TG) was 11.5- and 19.1-fold higher than that of the CTX solution, respectively, demonstrating good oral delivery efficiency. However, the excessive reduction sensitivity of the disulfide bond resulted in lower plasma stability and safety of CTX-S-S-TG than that of CTX-(C)S-(C)S-TG. Moreover, introducing steric hindrance into disulfide bonds could also modulate drug release and cytotoxicity, significantly improving the anti-tumor activity even compared to that of intravenous CTX solution at half dosage while minimizing off-target adverse effects. Our findings provide insights into the design and fine-tuning of different disulfide bond-based linkers, which may help identify oral prodrugs with more potent therapeutic efficacy and safety for cancer therapy. 展开更多
关键词 Steric disulfide bond Triglyceride-like pr odrugs CABAZITAXEL Lymphatic transport Oral chemotherapy
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Effect of Six Bacterial Strains on the Activity of Second Instar Larvae and Egg Hatching of Meloidogyne incognita
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作者 Jie LIU Li HE +4 位作者 zixuan wang Jianqing MA Xiaolong TONG Dandan CAO Gangyong ZHAO 《Plant Diseases and Pests》 2024年第5期15-18,共4页
[Objectives]The paper was to screen effective biocontrol strains against Meloidogyne incognita.[Methods]The effect of six bacterial strains sourced from the research group s strain library on the activity of second in... [Objectives]The paper was to screen effective biocontrol strains against Meloidogyne incognita.[Methods]The effect of six bacterial strains sourced from the research group s strain library on the activity of second instar larvae of M.incognita,as well as on egg hatching,was evaluated.[Results]The treatment of fermentation supernatant derived from the X-2 strain exhibited a pronounced lethal effect on M.incognita,with a corrected mortality rate reaching 97%within 72 h.Additionally,this treatment significantly inhibited egg hatching,achieving an inhibition rate of 94.69%at a 20-fold dilution.The strain was identified as Bacillus velezensis,belonging to the genus Bacillus,and was designated as RKN1111.[Conclusions]This study presents alternative strains and a theoretical framework for the biological control of M.incognita. 展开更多
关键词 Meloidogyne incognita Bacterial strain Second instar larvae Egg hatching
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表面富集的超小铂纳米颗粒耦合缺陷磷化钴用于高效的电催化水分解和柔性锌空气电池 被引量:1
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作者 吴则星 高玉肖 +7 位作者 王子璇 肖卫平 王新萍 李彬 李镇江 刘晓斌 马天翼 王磊 《Chinese Journal of Catalysis》 SCIE EI CAS CSCD 2023年第3期36-47,共12页
开发多功能的纳米电催化剂可以提高单位催化剂表面活性密度.本课题组采用热解和还原工艺制备了具有多功能电催化性能的超小铂纳米颗粒耦合缺陷CoP的纳米材料(Pt/d-CoP/NPC),它具有较高的氧还原反应(ORR)半波电位(0.82 V).所合成的Pt/d-C... 开发多功能的纳米电催化剂可以提高单位催化剂表面活性密度.本课题组采用热解和还原工艺制备了具有多功能电催化性能的超小铂纳米颗粒耦合缺陷CoP的纳米材料(Pt/d-CoP/NPC),它具有较高的氧还原反应(ORR)半波电位(0.82 V).所合成的Pt/d-CoP/NPC电催化剂具有良好的电催化析氢反应活性,当反应活性达到10 mA cm^(-2)时,过电位分别为33 mV@1mol/L KOH, 10 mV@0.5 mol/L H_(2)SO_(4)和70 mV@1 mol/L PBS.Pt/d-CoP/NPC催化剂还表现出较好的析氧反应活性.以合成的催化剂Pt/d-CoP/NPC作为电极组装的全解水装置和可充电锌空气电池具有良好的活性和稳定性,可以持续有效地驱动全解水产氢,在存储可再生能源方面的具有较好的应用潜力.采用X射线光电子能谱(XPS)、拉曼光谱测试和傅里叶红外光谱测试(FTIR)等技术研究了Pt颗粒与CoP之间的相互作用,并利用密度泛函理论(DFT)计算研究了催化剂的ORR反应机制.Pt/d-CoP/NPC在129.3 (2p_(3/2))和130.1 eV (2p_(1/2))处的P 2p轨道观察到P-M键,证实了金属磷化物的存在.Pt/d-CoP/NPC的Co结合能相对于d-CoP/NPC的结合能发生了正移,表明Pt与CoP之间存在电子相互作用.由于Co和Pt的电负性差异,Pt/d-CoP/NPC中Pt的峰值与商用Pt/C相比呈负移,说明电子从Co向Pt转移.XPS也证实了碳的存在.此外,拉曼光谱也出现了碳的特征峰D峰和G峰.并且Pt/d-CoP/NPC和d-CoP/NPC的ID/IG值相似,说明Pt的引入不会影响碳基体的结构.在N 1s光谱中,检测到N-P和吡啶氮的存在,证实在Pt/d-CoP/NPC和d-CoP/NPC中形成了N, P掺杂的碳.此外, Pt/d-CoP/NPC的FTIR谱出现对应于P-O, N-P, C-C, C-H和O-H的峰,也证明了氮磷共掺杂碳的存在.通过DFT计算进一步分析Pt/d-CoP/NPC电催化剂具有良好ORR活性的原因.结果表明,电荷从CoP转移到Pt,有利于活性氧分子的活化,促进催化过程.对比不同模型ORR过程中间体的自由能图, Pt/d-CoP/NPC和Pt/C的速率决定步骤为O_(2)生成OOH^(*),合成的Pt/d-CoP/NPC具有有利的热力学过电位,证明了其高效的ORR性能.此外, Pt/d-CoP/NPC中Pt的d带中心相对于纯Pt有明显的正向费米能级转移,说明引入的CoP可以导致离域电子重分布,从而优化了反应中间体的吸附.综上,Pt/d-CoP/NPC催化剂中Pt与CoP之间存在相互作用,进而提高催化活性,该催化剂的合成有望为开发多功能电催化纳米材料提供参考. 展开更多
关键词 三功能电催化剂 析氢/氧反应 氧还原反应 柔性锌空气电池 COP
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Effect of extracellular polymeric substances on Dolichospermum aggregation during temperature rise
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作者 Dailan DENG Han MENG +6 位作者 You MA Yongqi GUO zixuan wang Huan HE Khan WAQAS Jin’e LIU Limin ZHANG 《Journal of Oceanology and Limnology》 SCIE CAS CSCD 2023年第6期2208-2218,共11页
Dolichospermum,a typical model filamentous of cyanobacteria,has the potential to cause severely bloom.Extracellular polymeric substances(EPSs)are considered to influence the aggregation of the algae,and temperature is... Dolichospermum,a typical model filamentous of cyanobacteria,has the potential to cause severely bloom.Extracellular polymeric substances(EPSs)are considered to influence the aggregation of the algae,and temperature is a significant factor affecting EPSs secretion.However,the mechanism of how EPSs affects the aggregation of Dolichospermum is still unclear because the structure and composition of EPSs are complex.In this study,the effects of EPSs on the aggregation of Dolichospermum during the rise of temperature(7-37℃)were determined.The results showed that the concentration of extracellular polysaccharides and proteins changed significantly with increasing temperature(P<0.01).Firstly,during the increasing temperature,the polysaccharide content of EPSs increased from 20.34 to 54.64 mg/L,and the polysaccharides in the soluble EPS(S-EPS)layer changed significantly.The protein content reached maximum value at 21℃(14.52 mg/L)and varied significantly in S-EPS and loosely bound EPS(LB-EPS).In the EPSs matrix,humus substances and protein were main components of S-EPS and LB-EPS,and protein was the main component of tightly bound EPS(TB-EPS).Secondly,the cell density of Dolichospermum increased during the temperature rise while the aggregation ratio decreased.Moreover,zeta potential and surface thermodynamic analysis of Dolichospermum revealed that the interfacial free energy and electrostatic repulsion increased gradually with increasing temperature,which further reduced the aggregation of Dolichospermum.Finally,principal component analysis(PCA)analysis showed the aggregation of Dolichospermum was directly related to the changes of protein in EPSs(especially S-EPS and LB-EPS)and zeta potential,and polysaccharides in EPSs inhibited the aggregation of Dolichospermum.Based on these results,it was illustrated that the composition and concentration of EPSs affected the cell surface properties of Dolichospermum with the change of temperature and thus affected the aggregation of Dolichospermum. 展开更多
关键词 TEMPERATURE Dolichospermum extracellular polymeric substances AGGREGATION
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Hole‑Transport Management Enables 23%‑Efficient and Stable Inverted Perovskite Solar Cells with 84%Fill Factor
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作者 Liming Liu Yajie Ma +7 位作者 Yousheng wang Qiaoyan Ma zixuan wang Zigan Yang Meixiu Wan Tahmineh Mahmoudi Yoon‑Bong Hahn Yaohua Mai 《Nano-Micro Letters》 SCIE EI CAS CSCD 2023年第8期154-166,共13页
NiO_(x)-based inverted perovskite solar cells(PSCs)havepresented great potential toward low-cost,highly efficient and stablenext-generation photovoltaics.However,the presence of energy-levelmismatch and contact-interf... NiO_(x)-based inverted perovskite solar cells(PSCs)havepresented great potential toward low-cost,highly efficient and stablenext-generation photovoltaics.However,the presence of energy-levelmismatch and contact-interface defects between hole-selective contacts(HSCs)and perovskite-active layer(PAL)still limits device efficiencyimprovement.Here,we report a graded configuration based on bothinterface-cascaded structures and p-type molecule-doped compositeswith two-/three-dimensional formamidinium-based triple-halideperovskites.We find that the interface defects-induced non-radiativerecombination presented at HSCs/PAL interfaces is remarkably suppressedbecause of efficient hole extraction and transport.Moreover,astrong chemical interaction,halogen bonding and coordination bondingare found in the molecule-doped perovskite composites,whichsignificantly suppress the formation of halide vacancy and parasitic metallic lead.As a result,NiO_(x)-based inverted PSCs present a power-conversion-efficiency over 23%with a high fill factor of 0.84 and open-circuit voltage of 1.162 V,which are comparable to the best reported around 1.56-electron volt bandgap perovskites.Furthermore,devices with encapsulation present high operational stability over 1,200 h during T_(90) lifetime measurement(the time as a function of PCE decreases to 90%of its initial value)under 1-sun illumination in ambient-air conditions. 展开更多
关键词 Inverted NiO_(x)-based perovskite solar cells Hole-transport management Interface-induced defect passivation High performance and stability
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硼化钛耐磨涂层对织物性能的影响 被引量:2
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作者 苏青春 刘帅 +5 位作者 王子璇 龙柱 孙昌 张丹 黄婵娟 贾鹏飞 《高分子材料科学与工程》 EI CAS CSCD 北大核心 2021年第4期56-62,共7页
硼化钛具有较高的硬度和良好的耐磨性,而有机硅树脂的成膜性、疏水性、光泽性、耐刮擦性以及耐腐蚀性能皆优异。将硼化钛与有机硅树脂混合制成耐磨涂层,浸渍、喷涂于棉织物及涤纶织物表面,测试其一系列物理力学性能。实验结果表明,硼化... 硼化钛具有较高的硬度和良好的耐磨性,而有机硅树脂的成膜性、疏水性、光泽性、耐刮擦性以及耐腐蚀性能皆优异。将硼化钛与有机硅树脂混合制成耐磨涂层,浸渍、喷涂于棉织物及涤纶织物表面,测试其一系列物理力学性能。实验结果表明,硼化钛可以显著提高棉织物和涤纶织物的耐磨性能;有机硅树脂含量的增加直接影响涂层织物耐磨性能的提高,涂层织物拉伸断裂强力的提高以及涂层织物疏水性能的提高;当有机硅树脂质量分数低于50%时,涤纶织物的耐磨性能远高于棉织物,当有机硅树脂质量分数高于75%时,棉织物的耐磨性能高于涤纶织物;有机硅树脂质量分数为75%的涂层棉织物疏水性能最优,水接触角达到143.4°;有机硅树脂质量分数为100%的涂层涤纶织物疏水性能最优,水接触角达到152.1°。 展开更多
关键词 硼化钛 有机硅树脂 棉织物 涤纶织物 耐磨涂层
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利用聚多巴胺/叶酸制备超疏水棉织物 被引量:1
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作者 王子璇 季静怡 +2 位作者 聂宜苹 王娟 张丹 《高分子材料科学与工程》 EI CAS CSCD 北大核心 2021年第12期103-110,共8页
通过聚多巴胺(PDA)包裹叶酸(FA)自聚合形成微纳米结构,利用十六烷基三甲氧基硅烷(HDTMS)修饰粗糙表面,达到降低织物表面张力的目的,从而赋予棉织物超疏水性能,此时棉织物表面的接触角达到151.9°,滚动角达到8°。FA可以通过π-... 通过聚多巴胺(PDA)包裹叶酸(FA)自聚合形成微纳米结构,利用十六烷基三甲氧基硅烷(HDTMS)修饰粗糙表面,达到降低织物表面张力的目的,从而赋予棉织物超疏水性能,此时棉织物表面的接触角达到151.9°,滚动角达到8°。FA可以通过π-π相互作用和氢键共同诱导多巴胺(DA)的聚合。HDTMS与棉织物表面的羟基发生缩合反应以提高其疏水性。改性棉织物表面经过1000次摩擦后,接触角仍保持在130°以上,其物理力学性能仅略微下降。在满足棉织物基础应用的同时大幅度扩展了棉织物的应用范围。 展开更多
关键词 超疏水棉织物 聚多巴胺 叶酸 硅烷偶联剂
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pH可控改性聚乙烯胺自组装膜的制备
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作者 聂宜苹 王子璇 +2 位作者 季静怡 贾鹏飞 张丹 《高分子材料科学与工程》 EI CAS CSCD 北大核心 2022年第1期168-174,共7页
采用水溶性N-(3-二甲氨基丙基)-N'-乙基碳二亚胺盐酸盐(EDC)和N-羟基琥珀酰亚胺(NHS)为耦合剂制备了改性聚乙烯胺PVAm-DOPA和PVAm-PBA,并通过自组装的方式在硅板表面构建成一对高分子超薄膜,实现了PVAm-PBA和PVAm-DOPA之间基于可逆... 采用水溶性N-(3-二甲氨基丙基)-N'-乙基碳二亚胺盐酸盐(EDC)和N-羟基琥珀酰亚胺(NHS)为耦合剂制备了改性聚乙烯胺PVAm-DOPA和PVAm-PBA,并通过自组装的方式在硅板表面构建成一对高分子超薄膜,实现了PVAm-PBA和PVAm-DOPA之间基于可逆硼酸酯反应的可控自组装,并通过改变反应体系的pH值实现了硅板上自组装超薄膜表面的亲水性能调控。研究表明,PVAm-DOPA和PVAm-PBA的等电点分别为pH=10.5和pH=9.2;PVAm-DOPA和PVAm-PBA在硅板上所形成的自组装薄膜的厚度可由pH值进行控制,当pH值小于4时,薄膜厚度稳定在2nm左右,之后薄膜厚度随pH值的升高而增加并最终趋于稳定;同时,硅板上自组装薄膜表面的亲水性能也随着pH值的增大而提高。 展开更多
关键词 硼酸酯反应 改性聚乙烯胺 pH可控 自组装
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Fabrication of paper-based devices for in vitro tissue modeling 被引量:3
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作者 Hongbin Li Feng Cheng +3 位作者 Juan A.Robledo-Lara Junlong Liao zixuan wang Yu Shrike Zhang 《Bio-Design and Manufacturing》 SCIE CSCD 2020年第3期252-265,共14页
Paper devices have recently attracted considerable attention as a class of cost-effective cell culture substrates for various biomedical applications.The paper biomaterial can be used to partially mimic the in vivo ce... Paper devices have recently attracted considerable attention as a class of cost-effective cell culture substrates for various biomedical applications.The paper biomaterial can be used to partially mimic the in vivo cell microenvironments mainly due to its natural three-dimensional characteristic.The paper-based devices provide precise control over their structures as well as cell distributions,allowing recapitulation of certain interactions between the cells and the extracellular matrix.These features have shown great potential for the development of normal and diseased human tissue models.In this review,we discuss the fabrication of paper-based devices for in vitro tissue modeling,as well as the applications of these devices toward drug screening and personalized medicine.It is believed that paper as a biomaterial will play an essential role in the field of tissue model engineering due to its unique performances,such as good biocompatibility,eco-friendliness,cost-effectiveness,and amenability to various biodesign and manufacturing needs. 展开更多
关键词 Paper-based devices In vitro Tissue modeling Disease modeling Drug screening Personalized medicine
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A new Lactobacillus gasseri strain HMV18 inhibits the growth of pathogenic bacteria 被引量:4
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作者 Xiang Gao zixuan wang +10 位作者 Xiang Li Xiaoling Zhang Shengqiang Du Miaomiao Jia Dailun Hu Xianxian Jia Bin Cong Yan Zhang Chunling Ma Song Zhou Jun Zhang 《Food Science and Human Wellness》 SCIE 2022年第2期247-254,共8页
To search for a new eco-friendly therapy for infectious disease caused by Escherichia coli,Staphylococcus aureus or Klebsiella oxytoca,we collected the vaginal swabs from healthy women,screened for Lactobacillus and f... To search for a new eco-friendly therapy for infectious disease caused by Escherichia coli,Staphylococcus aureus or Klebsiella oxytoca,we collected the vaginal swabs from healthy women,screened for Lactobacillus and found a strain repressing the growth of pathogenic bacteria.The new isolate was identified as L.gasseri by the colony morphology,Gram staining,biochemical reactions and confirmed by the 16 S rDNA sequencing.The HMV18 strain inhibited the growth of food-borne pathogens such as E.coli,S.aureus and K.oxytoca.The HMV18 strain was sensitive to penicillin,ampicillin,erythromycin,tetracycline and chloramphenicol.The HMV18 strain producedα-hemolysis.Pathological histology of the mice ileum showed that the mucosa,villi,lamina propria and crypt depth remained intact and there was no inflammation or hyperemia in the L.gasseri HMV18 gavaged group.L.gasseri HMV18 could not up-regulate inflammatory cytokines level of plasma.All the results suggested L.gasseri HMV18 is a candidate probiotic to be an additive for food preservation or drug to prevent food-borne diseases. 展开更多
关键词 Lactobacillus gasseri ANTAGONISM BACTERIA Safety evaluation
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Application of photodynamic therapy in cancer: challenges and advancements 被引量:2
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作者 zixuan wang HONGMEI PENG +9 位作者 WEI SHI LU GAN LIPING ZHONG JIAN HE LINLIN XIE PAN WU YONGXIANG ZHAO ZHIMING DENG HONGLIANG TANG YONG HUANG 《BIOCELL》 SCIE 2021年第3期489-500,共12页
Although great achievements have been made in the past decades in medicine,cancer remains a worldwide public health issue.Surgery is usually accompanied by shortcomings such as residual lesions and poor treatment effe... Although great achievements have been made in the past decades in medicine,cancer remains a worldwide public health issue.Surgery is usually accompanied by shortcomings such as residual lesions and poor treatment effects,and the successive appearance of other treatment methods,such as radiotherapy and chemotherapy,has not changed the postoperative recurrence rate,toxicity,and side effects.However,the advent of photodynamic therapy has greatly improved this situation.Photodynamic therapy is an emerging tumor diagnosis and treatment technology with good application prospects,photodynamic therapy uses a specific wavelength of light to excite a photosensitizer to generate reactive oxygen species,damage tumor blood vessels and promote tumor cell apoptosis,exerting an anti-tumor effect.Photodynamic therapy has become a new clinical anti-tumor therapy due to its clear efficacy,few side effects,and easy use in combination with other therapies.In this review,we summarized the main mechanism,current challenges,and advancements of photodynamic therapy. 展开更多
关键词 Photodynamic therapy Reactive oxygen species PHOTOSENSITIZER CANCER MECHANISM
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Semisupervised Encrypted Traffic Identification Based on Auxiliary Classification Generative Adversarial Network 被引量:1
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作者 Jiaming Mao Mingming Zhang +5 位作者 Mu Chen Lu Chen Fei Xia Lei Fan zixuan wang Wenbing Zhao 《Computer Systems Science & Engineering》 SCIE EI 2021年第12期373-390,共18页
The rapidly increasing popularity of mobile devices has changed the methods with which people access various network services and increased net-work traffic markedly.Over the past few decades,network traffic identific... The rapidly increasing popularity of mobile devices has changed the methods with which people access various network services and increased net-work traffic markedly.Over the past few decades,network traffic identification has been a research hotspot in the field of network management and security mon-itoring.However,as more network services use encryption technology,network traffic identification faces many challenges.Although classic machine learning methods can solve many problems that cannot be solved by port-and payload-based methods,manually extract features that are frequently updated is time-consuming and labor-intensive.Deep learning has good automatic feature learning capabilities and is an ideal method for network traffic identification,particularly encrypted traffic identification;Existing recognition methods based on deep learning primarily use supervised learning methods and rely on many labeled samples.However,in real scenarios,labeled samples are often difficult to obtain.This paper adjusts the structure of the auxiliary classification generation adversarial network(ACGAN)so that it can use unlabeled samples for training,and use the wasserstein distance instead of the original cross entropy as the loss function to achieve semisupervised learning.Experimental results show that the identification accuracy of ISCX and USTC data sets using the proposed method yields markedly better performance when the number of labeled samples is small compared to that of convolutional neural network(CNN)based classifier. 展开更多
关键词 Encrypted traffic recognition deep learning generative adversarial network traffic classification semisupervised learning
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甘油选择性氧化制乳酸贵金属催化剂
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作者 谢浩东 胡尊龙 +4 位作者 魏豪斌 葛思达 王子轩 张玉明 吴志杰 《化学进展》 SCIE CAS CSCD 北大核心 2024年第7期1088-1101,共14页
生物柴油产量增加导致副产物甘油过剩问题愈加凸显,将甘油催化转化生成高附加值化学品具有重要意义。近年来,贵金属催化剂(Au、Pt、Pd等)常被用于催化甘油转化制乳酸,其中乳酸选择性和催化剂稳定性的提高是催化剂面临的关键挑战。本文... 生物柴油产量增加导致副产物甘油过剩问题愈加凸显,将甘油催化转化生成高附加值化学品具有重要意义。近年来,贵金属催化剂(Au、Pt、Pd等)常被用于催化甘油转化制乳酸,其中乳酸选择性和催化剂稳定性的提高是催化剂面临的关键挑战。本文介绍了负载型贵金属催化剂催化甘油选择性氧化制乳酸的反应机理,揭示了不同金属活性位点的作用,同时,围绕贵金属活性位的结构和电子性质,讨论了金属粒径、载体、反应体系pH对反应性能的影响,分析了贵金属与载体之间的强相互作用促进甘油分子羟基活化机制。最后,阐释了甘油选择性氧化制乳酸面临的主要挑战,并对未来的发展趋势进行了展望。 展开更多
关键词 甘油 乳酸 选择性氧化 贵金属 催化剂
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Characteristics of rural domestic sewage discharge and their driving mechanisms: evidence from the Northern Region, China 被引量:1
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作者 Jianguo Liu Ziyu Zhou +10 位作者 Pengyu Li zixuan wang Ying Yan Xuezheng Yu Wenkai Li Tianlong Zheng Yingnan Cao Wenjun Wu Wenqian Cai Zhining Shi Junxin Liu 《Frontiers of Environmental Science & Engineering》 SCIE EI CSCD 2024年第7期47-58,共12页
The traits of rural domestic sewage emission are unclear,negatively affecting rural domestic sewage treatment and sewage management.This study used data from the Second National Pollution Source Census Bulletin to est... The traits of rural domestic sewage emission are unclear,negatively affecting rural domestic sewage treatment and sewage management.This study used data from the Second National Pollution Source Census Bulletin to establish a data set.The spatial distribution characteristics and main factors influencing rural sewage discharge in the Northern Region were studied using spatial autocorrelation analysis and structural equations.The findings demonstrated that(l)a significant Spearman correlation between drainage water volume(DwV),chemical oxygen demand(COD),ammonia nitrogen(NH_(3)-N),total nitrogen(TN),and total phosphorus(TP)and that the correlation coefficients between DWV and COD,NH,-N,TNand TP were 0.87**,1.0**,0.99**,0.99**,respectively;(2)rural sewage discharge showed spatial autocorrelation,and rural domestic sewage discharge in the districts and counties with an administration was significantly higher than in the surrounding areas;and(3)social development was the main driver rural domestic sewage changes(path coefficient was 0.407**),and the main factors influencing rural domestic sewage discharge were the urbanization rate,years of education,and population age structure.This study obtained the spatial variation law and clarified the main influencing factors of rural domestic sewage to provide data support and a theoretical basis for subsequent rural sewage collection and treatment.Use of the Inner Mongolia Autonomous Region in northern China as a typical case,provides a theoretical foundation for scientific decision-making on rural domestic sewage treatment at the national and regional levels and offers new perspectives for managing pollutants. 展开更多
关键词 Rural domestic sewage Emission characteristics Spatial autocorrelation analysis Influencing factors
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The chromosome-scale assembly of the Notopterygium incisum genome provides insight into the structural diversity of coumarins
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作者 Qien Li Yiqun Dai +13 位作者 Xin-Cheng Huang Lanlan Sun Kaixuan wang Xiao Guo Dingqiao Xu Digao Wan Latai An zixuan wang Huanying Tang Qi Qi Huihui Zeng Minjian Qin Jia-Yu Xue Yucheng Zhao 《Acta Pharmaceutica Sinica B》 SCIE CAS CSCD 2024年第8期3760-3773,共14页
Coumarins,derived from the phenylpropanoid pathway,represent one of the primary metabolites found in angiosperms.The alignment of the tetrahydropyran(THP)and tetrahydrofuran(THF)rings with the lactone structure result... Coumarins,derived from the phenylpropanoid pathway,represent one of the primary metabolites found in angiosperms.The alignment of the tetrahydropyran(THP)and tetrahydrofuran(THF)rings with the lactone structure results in the formation of at least four types of complex coumarins.However,the mechanisms underlying the structural diversity of coumarin remain poorly understood.Here,we report the chromosome-level genome assembly of Notopterygium incisum,spanning 1.64 Gb,with a contig N50 value of 22.7 Mb and 60,021 annotated protein-coding genes.Additionally,we identified the key enzymes responsible for shaping the structural diversity of coumarins,including two p-coumaroyl CoA 2′-hydroxylases crucial for simple coumarins basic skeleton architecture,two UbiA prenyltransferases responsible for angular or linear coumarins biosynthesis,and five CYP736 cyclases involved in THP and THF ring formation.Notably,two bifunctional enzymes capable of catalyzing both demethylsuberosin and osthenol were identified for the first time.Evolutionary analysis implies that tandem and ectopic duplications of the CYP736 subfamily,specifically arising in the Apiaceae,contributed to the structural diversity of coumarins in N.incisum.Conclusively,this study proposes a parallel evolution scenario for the complex coumarin biosynthetic pathway among different angiosperms and provides essential synthetic biology elements for the heterologous industrial production of coumarins. 展开更多
关键词 Notopterygium incisum Parallel evolution BIOSYNTHESIS Pyranocoumarins FURANOCOUMARINS
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Visible-infrared-terahertz optical modulation of few-layer graphene through lithium intercalation
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作者 Ganying Zeng Zhenyu Fang +6 位作者 Weibao He zixuan wang Yijie Li Liantuan Xiao Suotang Jia Chengbing Qin Renyan Zhang 《Chinese Optics Letters》 SCIE EI CAS CSCD 2024年第9期108-113,共6页
Optical modulation is significant and ubiquitous to telecommunication technologies,smart windows,and military devices.However,due to the limited tunability of traditional doping,achieving broadband optical property ch... Optical modulation is significant and ubiquitous to telecommunication technologies,smart windows,and military devices.However,due to the limited tunability of traditional doping,achieving broadband optical property change is a tough problem.Here,we demonstrate a remarkable transformation of optical transmittance in few-layer graphene(FLG)covering the electromagnetic spectra from the visible to the terahertz wave after lithium(Li)intercalation.It results in the transmittance being higher than 90%from the wavelengths of 480 to 1040 nm,and it increases most from 86.4%to 94.1%at 600 nm,reduces from∼80%to∼68%in the wavelength range from 2.5 to 11μm,has∼20%reduction over a wavelength range from 0.4 to 1.2 THz,and reduces from 97.2%to 68.2%at the wavelength of 1.2 THz.The optical modification of lithiated FLG is attributed to the increase of Fermi energy(Ef)due to the charge transfer from Li to graphene layers.Our results may provide a new strategy for the design of broadband optical modulation devices. 展开更多
关键词 few-layer graphene INTERCALATION LiC12 optical modulation charge transfer
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Inversion of maize leaf nitrogen using UAV hyperspectral imagery in breeding fields
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作者 Qiwen Cheng Bingsun Wu +7 位作者 Huichun Ye Yongyi Liang Yingpu Che Anting Guo zixuan wang Zhiqiang Tao Wenwei Li Jingjing wang 《International Journal of Agricultural and Biological Engineering》 SCIE 2024年第3期144-155,共12页
Nitrogen(N)as a pivotal factor in influencing the growth,development,and yield of maize.Monitoring the N status of maize rapidly and non-destructive and real-time is meaningful in fertilization management of agricultu... Nitrogen(N)as a pivotal factor in influencing the growth,development,and yield of maize.Monitoring the N status of maize rapidly and non-destructive and real-time is meaningful in fertilization management of agriculture,based on unmanned aerial vehicle(UAV)remote sensing technology.In this study,the hyperspectral images were acquired by UAV and the leaf nitrogen content(LNC)and leaf nitrogen accumulation(LNA)were measured to estimate the N nutrition status of maize.24 vegetation indices(VIs)were constructed using hyperspectral images,and four prediction models were used to estimate the LNC and LNA of maize.The models include a single linear regression model,multivariable linear regression(MLR)model,random forest regression(RFR)model,and support vector regression(SVR)model.Moreover,the model with the highest prediction accuracy was applied to invert the LNC and LNA of maize in breeding fields.The results of the single linear regression model with 24 VIs showed that normalized difference chlorophyll(NDchl)had the highest prediction accuracy for LNC(R^(2),RMSE,and RE were 0.72,0.21,and 12.19%,respectively)and LNA(R^(2),RMSE,and RE were 0.77,0.26,and 14.34%,respectively).And then,24 VIs were divided into 13 important VIs and 11 unimportant VIs.Three prediction models for LNC and LNA were constructed using 13 important VIs,and the results showed that RFR and SVR models significantly enhanced the prediction accuracy of LNC and LNA compared to the multivariable linear regression model,in which RFR model had the highest prediction accuracy for the validation dataset of LNC(R^(2),RMSE,and RE were 0.78,0.16,and 8.83%,respectively)and LNA(R^(2),RMSE,and RE were 0.85,0.19,and 9.88%,respectively).This study provides a theoretical basis for N diagnosis and precise management of crop production based on hyperspectral remote sensing in precision agriculture. 展开更多
关键词 MAIZE NITROGEN hyperspectral imagery vegetation index UAV random forest regression support vector regression
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Finer-scale urban health risk assessment based on the interaction perspective of thermal radiation,human,activity,and space
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作者 Ruonan Guo Fei Guo +3 位作者 Jing Dong zixuan wang Ruwei Zheng Hongchi Zhang 《Frontiers of Architectural Research》 CSCD 2024年第3期682-697,共16页
Urban heat stress profoundly affects the health of residents.However,current research primarily focuses on quantifying the risk of urban heat based on LST,Ta,etc.,overlooking the crucial and intimate influence of cont... Urban heat stress profoundly affects the health of residents.However,current research primarily focuses on quantifying the risk of urban heat based on LST,Ta,etc.,overlooking the crucial and intimate influence of continuous intense solar radiation on human thermal comfort and health.Simultaneously,there is a lack of smaller units to support more precise planning.This study utilized the radiant heat stress intensity(RHSI)metric concentrating on the intensity and duration of thermal radiation,to develop a thermal-radiation induced health risk(TIHR)assessment system.Leveraging technologies such as the SOLWEIG model,Python,BERT,and GIS enables precise calculations of 12 spatial indices,including RHSI and Weibo heat.This facilitates a more accurate assessment of health risks at the smallest urban units(blocks)and directly guides planning.The application of this workflow in the case of Suoyuwan,Dalian,China,confirms its value,as it can be used to determine which blocks should be prioritized for specific aspects of risk prevention and control.The results show that some blocks exhibited differences in TIHR even within close proximity,with disaster-causing factors varying according to locations.This study proposes a novel assessment framework based on the interactive perspective of thermal radiation-human-activity-space. 展开更多
关键词 Health risk assessment Thermal radiation Finer-scale BLOCK Planning HUMAN-CENTERED
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用于损耗型集成光子器件的相变材料评价标准和设计策略
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作者 夏剑 董云潇 +4 位作者 龚俊桀 王子炫 王天赐 杨蕊 缪向水 《Science China Materials》 SCIE EI CAS CSCD 2024年第6期2008-2015,共8页
相变材料(PCM)具有优异的光学性质,在多种集成光子器件中极具应用前景,如光存储器、光开关和光神经形态计算器件.然而,由于集成光子器件相变材料光学性能评价标准的缺乏,新型相变材料的设计主要依赖于研究者的研究经验.本文基于相变光... 相变材料(PCM)具有优异的光学性质,在多种集成光子器件中极具应用前景,如光存储器、光开关和光神经形态计算器件.然而,由于集成光子器件相变材料光学性能评价标准的缺乏,新型相变材料的设计主要依赖于研究者的研究经验.本文基于相变光子器件的性能需求,引入材料品质因子(FOM2=Δk/kamor)来评价相变材料的光学性能,建立了针对损耗调制型相变光子器件相变材料的光学性能评价标准.FOM值的大小代表相变材料在构建高性能相变光子器件中的应用潜力,FOM值越大,相变材料应用于光子器件的限制就越小.在此基础上,本文基于光学带隙理论,建立了相变材料光学参数与FOM值之间的关系,开发了三种基于GST的新型光学相变材料.结果表明,氮等非金属元素掺杂可以提高GST的FOM值,有利于开发低损耗、高调制空间的损耗型相变光子器件和大规模损耗型相变光子阵列.除了FOM之外,相变材料的结晶温度也会影响器件的编程功耗、循环寿命和稳定性,这要求我们在实际应用场景中根据器件的需求选择合适的相变材料.总之,本文为相变材料的光学性能提供了评价标准,促进了集成光子器件应用中相变材料的定制设计. 展开更多
关键词 phase change materials figure of merit optical bandgap photonic devices
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