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Cenozoic Ephedraceae adaptation to global cooling in northwestern China 被引量:2
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作者 YunFa Miao xiaoli yan +1 位作者 YaJun Shao Bao yang 《Research in Cold and Arid Regions》 2011年第5期375-380,共6页
Ephedraceae has been applied largely as a drought indicator to reconstruct Cenozoic paleoenvironment and paleoclimate. However, temperature indication of Ephedraceae has been largely ignored. Here, we provide a record... Ephedraceae has been applied largely as a drought indicator to reconstruct Cenozoic paleoenvironment and paleoclimate. However, temperature indication of Ephedraceae has been largely ignored. Here, we provide a record of Ephedraceae percentage spanning from the Early Eocene to Middle Miocene (52-17 Myr B.P.) in the Xining Basin, northeastem Tibetan Plateau. This record is comparable to a compiled Cenozoic Ephedraceae record from five other basins in northwestern China. Both records show Ephedraceae percentages were high during the Early Eocene, and decreased gradually from the Middle Eocene to Late Oligocene, then maintained a stable level since the Late Oligocene. By comparing these two Ephedraceae records with the marine oxygen isotope record, we discuss the variation of Ephedmceae percentage in Middle Cenozoic in response to global temperature change. Ephedraceae percentage was high in the Early Paleogene, associated with subtropical or tropical vegetation types in a global greenhouse climate, and decreased in Early Oligocene, associated with global cooling, suggesting that Ephedmceae is warm-tolerant during the Paleogene. The low Ephedraceae percentages in the Late Oligocene and Miocene were uncoupled with global warming, which may imply that Ephedraceae began to adapt to a eurythermic climate in the inland desert environment of westem China. Such adaptation may be a response to the high topography of the Tibetan Plateau. 展开更多
关键词 Ephedraceae ADAPTATION TEMPERATURE Tibetan Plateau CENOZOIC
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Expression and Significance of MicroRNA-21 and P-gp in Colon Cancer Cells 被引量:1
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作者 xiaoli yan yanfang FAN +3 位作者 Peng yan Jing XUE Zhenhong LIU Jining ZHENG 《Medicinal Plant》 CAS 2020年第2期47-48,53,共3页
[Objectives]To investigate the expression and significance of miR-21 and P-gp in colon cancer cell line HCT-15.[Methods]RT-qPCR was used to detect the miR-21 and ABCB1 mRNA expression level of P-gp coding genes in nor... [Objectives]To investigate the expression and significance of miR-21 and P-gp in colon cancer cell line HCT-15.[Methods]RT-qPCR was used to detect the miR-21 and ABCB1 mRNA expression level of P-gp coding genes in normal colon mucosal cell NCM460 and colon cancer cell HCT-15,and Western Blot was used to detect the expression of P-gp in these two cell lines.[Results]The results of RT-qPCR showed that the expression level of miR-21 and ABCB1 mRNA in colon cancer cell HCT-15 was significantly higher than that in normal colon cell NCM460,and the difference was statistically significant(P<0.05).Western Blot results showed that the expression level of P-gp in HCT-15 was significantly higher than that in NCM460,and the difference was statistically significant(P<0.05).[Conclusions]The expression level of miR-21 and ABCB1 mRNA/P-gp in colon cancer cell HCT-15 was higher than that in normal colonic mucosal cell NCM460,and the relationship between miR-21 and multidrug resistance in colon cancer might be related to P-gp. 展开更多
关键词 COLORECTAL CANCER MIR-21 ABCB1 P-GP
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Expression of P-gp and miRNA-21 in Colorectal Cancer Tissues and the Clinical Significance 被引量:1
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作者 xiaoli yan Peng yan +3 位作者 yanfang FAN Jing XUE Mingjuan WANG Jining ZHENG 《Medicinal Plant》 CAS 2020年第6期98-101,共4页
[Objectives]To study the expression of P-gp and miRNA-21 in colorectal cancer tissues and the relationship between the expression of P-gp and clinicopathological features,and to analyze the correlation between the exp... [Objectives]To study the expression of P-gp and miRNA-21 in colorectal cancer tissues and the relationship between the expression of P-gp and clinicopathological features,and to analyze the correlation between the expression of miRNA-21 and P-gp.[Methods]Immunohistochemical SP method was used to detect the expression level of P-gp in the tissues of 40 cases of colorectal cancer and the normal mucosal tissues 5 cm away from the corresponding cancer tissues,and the expression level of miRNA-21 in the paraffin tissues of the 40 cases was detected by RT-qPCR.[Results]The positive expression of P-gp was localized in the cell membrane,and the expression in colorectal cancer tissues was significantly higher than that in the corresponding adjacent tissues(P<0.05);the positive expression of P-gp was closely related to the degree of tumor differentiation and the depth of invasion(P<0.05),and the comparison results of P-gp expression in the differentiation groups of different cancer tissues showed that the expression level of P-gp in the moderately and poorly differentiated groups was significantly higher than that in the highly differentiated group(P<0.05),and the expression level of the moderately and poorly differentiated groups was similar(P>0.05).The expression of miRNA-21 in all cancer tissues was higher than that in the corresponding adjacent tissues(P<0.05),and the expression levels of miRNA-21 in differentiation groups of different cancer tissues were 1.286,1.445 and 1.992 times of those in the corresponding adjacent tissues,respectively;the comparison results of miRNA-21 between different differentiation groups showed that the expression level of miRNA-21 in the poorly differentiated group was significantly higher than that in the highly differentiated group and the moderately differentiated group(P<0.05),while the expression level of miRNA-21 in the highly differentiated group and the moderately differentiated group was similar(P>0.05).Spearman correlation analysis showed that there was a positive correlation on the expression between the two in colorectal cancer tissues(r=0.423,P<0.05).[Conclusions]The expression levels of miRNA-21 and P-gp are closely related to the differentiation degree of clinical colorectal cancer,the lower the differentiation degree,the higher the expression level of the two. 展开更多
关键词 Colorectal cancer P-GP MIRNA-21
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Effect of ATM/CHK2/CDC25A Signal Pathway on the Resistance of Colorectal Cancer Cells to L-OHP 被引量:1
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作者 xiaoli yan Peng yan +2 位作者 Jing XUE yanfang FAN Jining ZHENG 《Medicinal Plant》 CAS 2021年第3期69-71,共3页
[Objectives]To compare the expression of key factors ATM,CHK2,CDC25A and CDK2 in ATM/CHK2/CDC25A signal pathway in colorectal cancer cell line HCT116 and L-OHP-resistant cell line HCT116/L-OHP,and to explore the relat... [Objectives]To compare the expression of key factors ATM,CHK2,CDC25A and CDK2 in ATM/CHK2/CDC25A signal pathway in colorectal cancer cell line HCT116 and L-OHP-resistant cell line HCT116/L-OHP,and to explore the relationship between ATM/CHK2/CDC25A signal pathway and resistance of colorectal cancer cells to L-OHP.[Methods]RT-qPCR was used to detect the expression of ATM,CHK2,CDC25A and CDK2 mRNA in colorectal cancer cell line HCT116 and L-OHP-resistant cell line HCT116/L-OHP,and Western blot was used to detect the expression of corresponding proteins in these two cell lines.[Results]The expression of ATM,CHK2,CDC25A,CDK2 mRNA and protein in HCT116/L-OHP was significantly higher than that in HCT116.[Conclusions]ATM/CHK2/CDC25A signal pathway was associated with resistance of colorectal cancer cell line HCT116 to L-OHP.Blocking this signal pathway may partially reverse the chemotherapy resistance of colorectal cancer patients with L-OHP resistance. 展开更多
关键词 Colorectal cancer ATM CHK2 CDC25A
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Non-structural carbohydrate levels of three co-occurring understory plants and their responses to forest thinning by gap creation in a dense pine plantation
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作者 Zhe Wang Weikai Bao xiaoli yan 《Journal of Forestry Research》 SCIE CAS CSCD 2015年第2期391-396,共6页
We investigated non-structural carbohydrates(NSC) levels and components(starch,glucose,fructose and sucrose) in the leaves of three typical co-occurring forestfloor plants,moss Eurhynchium savatieri(ES),fern Par... We investigated non-structural carbohydrates(NSC) levels and components(starch,glucose,fructose and sucrose) in the leaves of three typical co-occurring forestfloor plants,moss Eurhynchium savatieri(ES),fern Parathelypteris nipponica(PN) and forb Aruncus sylvester(AS) in a 30-year-old Chinese pine(Pinus tabulaeformis)plantation forest on the eastern Tibetan Plateau.We also explored their responses to three gap creation treatments(control and two gap creations of 80 and 110 m2) based on NSC levels.PN had the highest leaf NSC level of the three plants,with AS second and ES lowest.Starch was the predominant component of NSC and the contents of glucose were higher than those of fructose or sucrose for all three species.The NSC level of ES in intermediate gaps was significantly higher than at control sites.PN also had higher NSC levels in both small and intermediate gaps than in control sites.But the differences between treatments were not obvious for AS.Our results suggest that ES and PN benefit from gap formation while the two species have different NSC response sensitivities to gap size,but the leaf NSC level of AS is less sensitive to the disturbance. 展开更多
关键词 Forest-floor plant Gap thinning Light radiation MOSS Non-structural carbohydrates
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Effects of Paeonol Combined with Panax Notoginseng Saponins on Nrf2/ARE Pathway in Rats with Diabetic Cardiomyopathy
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作者 yanfang FAN xiaoli yan +2 位作者 Zhuoya JIA Kaihang SHI Kai CAO 《Medicinal Plant》 CAS 2020年第1期37-39,43,共4页
[Objectives]To investigate whether paeonol(Pae)combined with panax notoginseng saponins(PNS)can protect the myocardium of rats with diabetic cardiomyopathy(DCM)through improving the antioxidant capacity of the rats by... [Objectives]To investigate whether paeonol(Pae)combined with panax notoginseng saponins(PNS)can protect the myocardium of rats with diabetic cardiomyopathy(DCM)through improving the antioxidant capacity of the rats by activating the Nrf2/ARE pathway.[Methods]The rats were fed with high-fat and high-sugar diet for 6 weeks,and combined with intraperitoneal injection of small-dose STZ to build a type II diabetes model;the model rats were randomly divided into a model group,a Pae group of 80 mg/kg,and a PNS group of 100 mg/kg,a Pae 80 mg/kg+PNS 100 mg/kg,and a metformin group 157.5 mg/kg;rats of normal group and model group were injected with an equal volume of sodium carboxymethyl cellulose(1%),10 rats in each group.After 8 weeks,3 rats in the model group were taken for histopathological examination.Changes in myocardial fibrosis and myocardial collagen formation indicated that the building of DCM model was successful.qRT-PCR and Western blot were used to detect the expression levels of Nrf2,HO-1,Col-I,and Col-III in myocardial tissue of each group of rats.[Results]Compared with the normal group,the mRNA and protein expression levels of Nrf2 and HO-1 in myocardial tissue of the DCM group rats were significantly reduced,and the mRNA and protein expression levels of Col-I and Col-III were significantly increased;compared with the DCM group,the mRNA and protein expression levels of Nrf2 and HO-1 in the myocardial tissue of each drug group increased to varying degrees,and the combined drug group increased more significantly than that of the single drug group;the mRNA and protein expression levels of Col-I and Col-III were reduced to varying degrees,and the combined drug group declined more significantly than that of the single drug group.[Conclusions]Paeonol combined with panax notoginseng saponins can up-regulate the expression of Nrf2 and HO-1 in myocardial tissue,inhibit the expression of type I and type III collagen.The mechanism may be related to improving the DCM myocardial fibrosis through activating the Nrf2/ARE pathway. 展开更多
关键词 PAEONOL PANAX notoginseng SAPONINS Diabetic CARDIOMYOPATHY MYOCARDIAL FIBROSIS Nrf2/ARE
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Effects of Budesonide Aerosol Inhalation on Perioperative Lung Function in Patients Undergoing Cardiopulmonary Bypass Valve Replacement
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作者 Yongliang CHEN Jing XUE +3 位作者 Daguang FANG xiaoli yan Xuefei TIAN Shulei XU 《Medicinal Plant》 CAS 2021年第5期97-99,共3页
[Objectives]To explore the effects of budesonide aerosol inhalation on the perioperative pulmonary function of patients undergoing cardiopulmonary bypass valve replacement.[Methods]A total of 82 patients who underwent... [Objectives]To explore the effects of budesonide aerosol inhalation on the perioperative pulmonary function of patients undergoing cardiopulmonary bypass valve replacement.[Methods]A total of 82 patients who underwent cardiopulmonary bypass valve replacement during January 2018 and May 2019 in the Affiliated Hospital of Chengde Medical College were selected.They were divided into blank control group(group A,n=28),aerosol control group(group B,n=27,normal saline aerosol treatment),and experimental group(group C,n=27,budesonide aerosol treatment)by the random number table method.Corresponding treatments were given 5 d before surgery and 5 d after surgery,and the treatment effects of the 3 groups were compared.[Results]The clinical symptom scores of the patients in the experimental group were significantly lower than those in the blank control group and the aerosol control group,and the total effective rate of treatment was significantly higher than that in the blank control group.[Conclusions]Perioperative application of budesonide aerosol inhalation can effectively improve the clinical symptoms,treatment effect,and clinical prognosis of patients undergoing cardiopulmonary bypass valve replacement. 展开更多
关键词 Cardiopulmonary bypass Valve replacement Aerosol inhalation Lung function
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Observations of the solar corona during the total solar eclipse on 21 August 2017
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作者 Hui Tian ZhongQuan Qu +15 位作者 YaJie Chen LinHua Deng ZhengHua Huang Hao Li Yue Zhong Yu Liang JingWen Zhang YiGong Zhang BaoLi Lun XiangMing Cheng xiaoli yan ZhiKe Xue YuXin Xin ZhiMing Song YingJie Zhu Tanmoy Samanta 《Earth and Planetary Physics》 2017年第1期68-71,共4页
The Sun’s tenuous outer atmosphere,the corona,emits only about one-millionth as much light as the solar surface.In ancient times the corona was observed by human beings only during total solar eclipses,when the stron... The Sun’s tenuous outer atmosphere,the corona,emits only about one-millionth as much light as the solar surface.In ancient times the corona was observed by human beings only during total solar eclipses,when the strong emission of visible light from the photosphere was completely blocked by the Moon.In 1931, 展开更多
关键词 solar corona solar eclipse solar magnetic fields coronal heating
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The effects of different sterilization methods on silk fibroin
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作者 Yahong Zhao xiaoli yan +2 位作者 Fei Ding Yumin yang Xiaosong Gu 《Journal of Biomedical Science and Engineering》 2011年第5期397-402,共6页
The aim of this study was to investigate the changes in the molecular structure and physiological activities of silk fibroin induced by three different sterilization methods (steam, gamma radiation and ethylene oxide)... The aim of this study was to investigate the changes in the molecular structure and physiological activities of silk fibroin induced by three different sterilization methods (steam, gamma radiation and ethylene oxide) with different dose or time period of sterilization by means of Fourier transform infrared (FT-IR) spec-troscopy, X-ray diffraction, mechanical properties and assessment of molecular weight. The results showed that the steam sterilization darkened the color of silk fibroin and obviously affected the mechanical property;gamma irradiation slightly degraded the molecular weight of silk fibroin and the speed of degradation increased with increasing irradiation dose;and ethylene oxide almost had no influence on silk fibroin expect for some slight hydrolysis on mo-lecular weight. Because ethylene oxide sterilization had the smallest influence on the quality of silk fi-broin with compared to other sterilization methods, it could be used as an efficient method to make fibroin more suitable for the development of functional foods and cosmetics. 展开更多
关键词 SILK Fibroin STERILIZATION DEGRADATION MECHANICAL PROPERTIES
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Research Progress on the Relationship Between Mitochondrial Dysfunction and Premature Ovarian Failure from the Perspective of TCM Treatment
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作者 xiaoli yan Nan Li 《Journal of Clinical and Nursing Research》 2022年第4期69-74,共6页
Premature ovarian failure(POF)is a prevalent yet challenging condition in gynecology.Its incidence rate has been steadily rising in recent years and is trending among younger age groups.The premature failure of ovaria... Premature ovarian failure(POF)is a prevalent yet challenging condition in gynecology.Its incidence rate has been steadily rising in recent years and is trending among younger age groups.The premature failure of ovarian function,which poses a serious threat to women’s physical and mental health,has emerged as a topic of concern in current research.At present,it is believed that the causes of premature ovarian failure are multifaceted,and its pathogenesis is complex,some of which are still not well-understood.Therefore,this article discusses the research progress of the pathogenesis of premature ovarian failure caused by mitochondrial dysfunction and serves as a reference for the prevention and further research of this condition from the perspective of traditional Chinese medicine treatment. 展开更多
关键词 Premature ovarian failure MITOCHONDRION Granulosa cells OOCYTE Traditional Chinese medicine
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Two-Dimensional Conductive Metal-Organic Framework Reinforced Spinterface in Organic Spin Valves
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作者 Xiaoyu Song Chao Jin +7 位作者 Hongliang Chen Shuaishuai Ding Zhongyi Liu yang Li xiaoli yan Wenbo Mi Long Chen Wenping Hu 《CCS Chemistry》 CSCD 2024年第1期208-217,共10页
Interface engineering in device fabrication is a significant but complicated issue.Although great successes have been achieved by conventional physical in situ or ex situ methods,it still suffers from complicated proc... Interface engineering in device fabrication is a significant but complicated issue.Although great successes have been achieved by conventional physical in situ or ex situ methods,it still suffers from complicated procedures.In this work,we present a facile method for fabricating phthalocyanine(Pc)-based two-dimensional conductive metal–organic framework(MOF)films.Based on PcM-Cu(M=Ni,Cu,H_(2))MOF films,spin valves with a vertical configuration of La_(0.67)Sr_(0.33)MnO_(3)/PcM-Cu MOFs/Co were constructed successfully,and exhibited notably high negative magnetoresistance(MR)up to -22% at 50 K.The penetrated Co atoms coordinated with the dehydrogenated hydroxy groups in the MOFs resulting in an antiferromagnetic layer of the PcM-Cu-Co hybrid structure.Interestingly,a significant exchange bias effect was demonstrated at the PcM-Cu MOF/Co interface,beneficial for the MR behavior.Thus,our present study provides new insights into developing high-performance organic spin valves via de novo molecular design. 展开更多
关键词 two-dimensional conductive metal-organic framework two-dimensional polymer PHTHALOCYANINE SPINTRONICS organic spin valve
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A Pyrazine-Based 2D Conductive Metal-Organic Framework for Efficient Lithium Storage 被引量:1
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作者 Xiaoxiao Sun xiaoli yan +5 位作者 Keming Song Ting Zhang Zongfan yang Xi Su Weihua Chen Long Chen 《Chinese Journal of Chemistry》 SCIE CAS CSCD 2023年第14期1691-1696,共6页
The merits of intrinsic electrical conductivity, high specific surface area, tunable chemical composition and tailor-made properties enable two-dimensional conductive metal-organic frameworks (2D c-MOFs) as promising ... The merits of intrinsic electrical conductivity, high specific surface area, tunable chemical composition and tailor-made properties enable two-dimensional conductive metal-organic frameworks (2D c-MOFs) as promising next-generation electrode materials in the field of energy storage and conversion. Herein, we have designed and synthesized a novel pyrazine-based 2D c-MOF (TPQG-Cu-MOF) bearing extended π-conjugated structure and abundant redox active sites. Thanks to the excellent redox reversibility of pyrazine units and CuO2 units, as well as the insolubility of the rigid framework skeleton, TPQG-Cu-MOF as the cathode material of lithium-ion battery exhibits a reversible specific capacity (150.2 mAh·g–1 at 20 mAh·g–1), good cycling stability (capacity retention of 82.6% after 500 cycles at 1 A·g–1) and excellent rate performance. Comprehensive ex-situ spectroscopic studies revealed the reversible redox activity of pyrazine units and CuO2 units of TPQG-Cu-MOF during the Li+ insertion/extraction process. The deepening fundamental understanding of the structure-property relationship was proposed, which might pave the way for further development of efficient MOF-based energy storage devices. 展开更多
关键词 TWO-DIMENSIONAL Conductive metal-organic frameworks PYRAZINE Energy storage Lithium-ion battery CATHODE Stability ComprehensiveSummary
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Heterogeneous photocatalytic borylation of aryl iodides mediated by isoreticular 2D covalent organic frameworks
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作者 Pengna Shang xiaoli yan +3 位作者 yang Li Junji Liu Guang Zhang Long Chen 《Chinese Chemical Letters》 SCIE CAS CSCD 2023年第5期594-597,共4页
Metal-free heterogeneous photocatalysts provide an environmental-friendly and cost-efficient avenue for green organic synthesis.Covalent organic frameworks(COFs)as heterogeneous photocatalysts showcase promising poten... Metal-free heterogeneous photocatalysts provide an environmental-friendly and cost-efficient avenue for green organic synthesis.Covalent organic frameworks(COFs)as heterogeneous photocatalysts showcase promising potential in the field of photocatalytic organic reactions due to their high porosity,insolubility and tailor-made functions.However,thus far,COF-based catalysts only mediated a few types of reactions.Herein,we developed a series of isoreticular nitrogen-rich covalent organic frameworks(N-COFs)with comparable porous structures as photocatalysts which effectively mediated the borylation of aryl iodides with broad substrate scope.Remarkably,6N-COF exhibits excellent photocatalytic efficiency and superior recyclability.It suggests a new pathway to construct efficient heterogeneous photocatalysts for the borylation of aryl halides. 展开更多
关键词 Covalent organic frameworks Nitrogen-rich Heterogeneous photocatalysis BORYLATION Green organic synthesis
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Efficacy of Huadananshen mistura on insomnia: a randomized, double-blind, placebo-controlled, and multi-center clinical trial 被引量:4
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作者 Huafang Li xiaoli yan +3 位作者 Ting Li Jian Xu Qiaochu Wang Yifeng Xu 《Journal of Traditional Chinese Medicine》 SCIE CAS CSCD 2013年第4期423-427,共5页
OBJECTIVE: To evaluate the effect of Huadananshen mistura in clinical treatment of Chinese patients with insomnia. METHODS: In this randomized, double-blind, placebo-controlled, multi-center study, 244 patients with i... OBJECTIVE: To evaluate the effect of Huadananshen mistura in clinical treatment of Chinese patients with insomnia. METHODS: In this randomized, double-blind, placebo-controlled, multi-center study, 244 patients with insomnia were randomly assigned to a placebo group, a low-dose (10 mL/day), or a high-dose (20 mL/day) mistura group. Efficacy was assessed by using the sleep dysfunction rating scale (SDRS) and Clinical Global Impression-Improvement (CGI-I) scores. Safety and tolerability assessments included emergent adverse events, laboratory tests, and electrocardiograms. RESULTS: Total SDRS scores decreased in all three groups, and there were significant differences between the placebo group and the lowand high-dose mistura groups (P=0.000). CGI-I ratings in the lowand high-dose mistura groups were sig-nificantly better than that of the placebo group (P= 0.000). Incidences of rebound insomnia were similar in all three groups (placebo group: 6.94% , low-dose mistura group: 12.99% , and high-dose mistura group: 10.96% ; P=0.475). The efficacy of Huadananshen mistura in the lowor high-dose group was significantly better than that of the placebo group (P=0.000), but with no significant difference found between the lowand high-dose mistura groups (P=0.887). The rates of adverse events were similar in the three groups (placebo 2.44% , low-dose mistura 0%, and high-dose mistura 5%; P=0.088). CONCLUSION: Huadananshen mistura is an effective and generally well-tolerated hypnotic medicine for the treatment of Chinese patients with insomnia. 展开更多
关键词 临床试验 失眠症 多中心 随机 疗效 临床治疗 高剂量 实验室检查
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Puromycin A, B and C, cryptic nucleosides identified from Streptomyces alboniger NRRL B-1832 by PPtase-based activation 被引量:3
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作者 xiaoli yan Benyin Zhang +6 位作者 Wenya Tian Qi Dai Xiaoqin Zheng Ke Hu Xinxin Liu Zixin Deng Xudong Qu 《Synthetic and Systems Biotechnology》 SCIE 2018年第1期76-80,共5页
Natural product discovery is pivot for drug development,however,this endeavor is often challenged by the wide inactivation or silence of natural products biosynthetic pathways.We recently developed a highly efficient ... Natural product discovery is pivot for drug development,however,this endeavor is often challenged by the wide inactivation or silence of natural products biosynthetic pathways.We recently developed a highly efficient approach to activate cryptic/silenced biosynthetic pathways through augmentation of the phosphopantetheinylation of carrier proteins.By applying this approach in the Streptomyces alboniger NRRL B-1832,we herein identified three cryptic nucleosides products,including one known puromycin A and two new derivatives(puromycin B and C).The biosynthesis of these products doesn't require the involvement of carrier protein,indicating the phosphopantetheinyl transferase(PPtase)indeed plays a fundamental regulatory role in metabolites biosynthesis.These results demonstrate that the PPtasebased approach have a much broader effective scope than the previously assumed carrier proteininvolving pathways,which will benefit future natural products discovery and biosynthetic studies. 展开更多
关键词 PUROMYCIN Phosphopantetheinyl transferase Gene activation Streptomyces alboniger Genome mining
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Donor-acceptor 2D covalent organic frameworks for efficient heterogeneous photocatalyticα-oxyamination
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作者 Huan Liu xiaoli yan +6 位作者 Weiben Chen Zhen Xie Shen Li Weihua Chen Ting Zhang Guolong Xing Long Chen 《Science China Chemistry》 SCIE EI CSCD 2021年第5期827-833,共7页
Covalent organic frameworks(COFs)have received widespread interest due to their high porosity,excellent crystallinity,tailorable structures,and broad application prospects.It has been demonstrated that proper combinat... Covalent organic frameworks(COFs)have received widespread interest due to their high porosity,excellent crystallinity,tailorable structures,and broad application prospects.It has been demonstrated that proper combination and arrangement of electron donor and acceptor units in 2D conjugated COF lattice could promote efficient charge separation and electron transfer,and thus is beneficial for photocatalysis.In this article,three donor-acceptor(D-A)2D COFs were prepared by Schiff base reaction of electron acceptor 4,4′,4′′,4′′′-(benzo[1,2-d:4,5-d′]bis(oxazole)-2,4,6,8-tetrayl)tetraaniline(BBO)with different electron donors:thieno[3,2-b]thiophene-2,5-dicarbaldehyde(TT),benzo[1,2-b:4,5-b’]dithiophene-2,6-dicarboxaldehyde(BDT)and terephthalaldehyde(Ph),respectively.These D-A 2D COFs exhibited prominent photocatalytic activity towardsα-oxyamination of 1,3-dicarbonyl with 2,2,6,6-tetramethyl-1-piperdinyloxy(TEMPO)upon visible light irradiation.Among these D-ABBO-COFs,DTT-ABBO-COF exhibited the highest photocatalytic rates,which can be ascribed to the more negative highest occupied molecular orbital(HOMO)and narrower bandgap.The excellent stability,high activity and superior recyclability render DTT-ABBO-COF as a potential and environmentally friendly heterogeneous catalyst forα-oxyamination. 展开更多
关键词 covalent organic frameworks DONOR-ACCEPTOR benzodioxazole heterogeneous photocatalysis α-oxyamination
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