可转债强赎股价效应的影响因素研究

选取2013-2022年225家A股上市公司发行的242只可转债,采用多元线性回归法对其强赎公告股价效应的影响因素进行实证研究。研究发现:①公司发布强赎公告对股价产生了负效应;②可转债相对发行规模、剩余规模对累计异常收益率呈现显著负相关关系。研究结论验证了可转债强赎公告的市场效应,证实了可转债累计异常收益率的主要影响因素,因此,提出了对可转债发行公司、投资者、市场监管者的对策建议。

柔性传动系统动力学建模及参数整定仿真分析

为分析柔性机械传动系统的动力学特性和控制参数对进给系统动力学特性的影响,文章建立了柔性机械传动系统的多惯量Simulink仿真模型,分析了多惯量模型的频率特性和时域响应;分别采用高阶最佳和考虑低阶谐振的方法对多惯量系统进行了控制参数整定和仿真分析。结果表明,考虑低阶谐振的参数整定方法能够在保证快速响应的基础上有效减小系统振荡,缩短系统调整时间,与高阶最佳系统整定结果相比具有更好的低通特性和高频谐振抑制能力。

一氧化氮对冷藏鲜切桃贮藏品质的影响

为探究适宜的鲜切桃冷藏条件下抑制褐变的方法,将鲜切"蒙阴"桃分别在清水(对照)、5、10、15μmol/L一氧化氮(NO)溶液中浸泡5 min,并于5℃下贮藏10 d,研究NO对鲜切桃贮藏期间品质的影响。结果表明,与对照相比,NO处理有效延缓了鲜切桃片褐变度的升高以及硬度、L^*值、可溶性固形物含量的下降,从而使鲜切桃在贮藏期间保持了较好的外观品质;同时NO处理减低了多酚氧化酶(PPO)和过氧化物酶(POD)活性高峰值,从而降低了褐变程度,提高了鲜切桃超氧化物歧化酶(SOD)和过氧化氢酶(CAT)活性,抑制了丙二醛(MDA)、活性氧(ROS)和总酚含量的上升,提高了鲜切桃片的贮藏品质,其中以10μmol/L NO保鲜效果最好。由此表明,10μmol/L NO处理是一种较好的抑制鲜切桃褐变的加工方法。

The impact of urban planning on land use and land cover in Pudong of Shanghai, China

Functional zones in cities constitute the most conspicuous components of newly developed urban areas, and have been a hot spot for domestic and foreign investors in China, which not only show the expanse of urban space accompanied by the shifts both in landscape (from rural to urban) and land use(from less extensive to extensive), but also display the transformation of regional ecological functions. By using the theories and methods of landscape ecology, the structure of landscapes and landscape ecological planning can be analyzed and evaluated for studying the urban functional zones' layout. In 1990, the Central Government of China declared to develop and open up Pudong New Area so as to promote economic development in Shanghai. Benefited from the advantages of Shanghai's location and economy, the government of Pudong New Area has successively built up 7 different functional zones over the past decade according to their functions and strategic goals. Based on the multi-spectral satellite imageries taken in 1990, 1997 and 2000, a landscape ecology analysis was carried out for Pudong New Area of Shanghai, supported by GIS technology. Green space (including croplands) and built-up areas are the major factors considered in developing urban landscape. This paper was mainly concerned with the different spatial patterns and dynamics of green space, built-up areas and new buildings in different functional zones, as influenced by different functional layouts and development strategies. The rapid urbanization in Pudong New Area resulted in a more homogeneous landscape. Agricultural landscape and suburban landscape were gradually replaced by urban landscape as the degree of urbanization increased. As a consequence of urbanization in Pudong, not only built-up patches, but also newly-built patches and green patches merged into one large patch, which should be attributed to the construction policy of extensive green space as the urban development process in Pudong New Area. The shape of green area of 7 functional zones became more and more regular because of the horticultural needs in Shanghai urban planning. Some suggestions were finally made for the study of future urban planning and layout.

高风险多元协同创业收益分配格局

深层次剖析双边道德风险条件下创业合作决策对合作关系的影响作用机理,构建创业合作的一般性纳什谈判博弈,设计服务协议约束下双方合作的中庸策略,基于"奖励与惩罚激励并举"的合作决策思想,对双边道德风险条件下的4种创业合作均衡进行比较分析。实例研究发现:中庸或聚点策略对创业合作绩效及公正性都具有显著的负向影响,奖励措施下的收益转移互助模式相比惩罚措施下的非合作预案模式,对创业合作具有更为关键的正向推动作用。基于此,分别从谈判、博弈规则、信息与资源管理等方面提出了最优化创业合作决策建议,以有效抑制双边道德风险,真正消除创业过程中的漠然状态,最大限度地促进创业合作关系,提升创业合作绩效,加快创业企业成长,更好地实现高层次人才创业企业的长期可持续性发展目标。

Hippocampal PPARδ downregulation contri butes to depressive phenotype with decreased neurogenesis

Our previous study showed that up-regulating hippocampal peroxisome proliferator-activated receptorδ(PPARδ)displays an antidepressive effect and enhanc-es hippocampal neurogenesis in the context of chronic stress.Here,the changes in depressive behaviors and hippocampal neurogenesis were investigated after PPARδknockdown by microinfusion of the lentiviral vector,expressing short hairpin RNA(sh RNA)complementary to the coding exon of PPARδ,into the bilateral dentate gyri of the hippocampus or PPARδblockade by repeated systemic administration of PPARδantagonist,GSK0660(1 or 3mg·kg-1,ip,for 21 d).We found that hippocampal PPARδknockdown or blockade induced depressive-like behaviors and increased vulnerability to stress,which is involved in decreased hippocampal neurogenesis and neuronal differentiation.Down-regulating hippocampal PPARδalso induced significant decreases in phosphorylation c AMP response element-binding protein(CREB)and BDNF level in the hippocampus.The in vitro study that PPARδknockdown or blockade inhibited proliferation and differentiation of neural stem cells.Taken together,our results suggest that PPARδcould be a novel and promising target for developing new PPARδagonists for the treatment of depressive disorders.

生产性服务业与制造业的互动差异——基于区域及行业视角

为归纳生产性服务业与制造业的互动机制,本文运用投入产出统计数据测算了二者的融合效应及波及效应,并对其互动影响程度进行了细分行业及地域间的比较实证分析。结果发现:R&D等服务业的中间需求率快速上升;制造业对生产性服务的消耗水平偏低,但与技术含量呈正比,通用设备等的投入端融合效应更显著,投入融合程度呈U型变化轨迹;制造业的波及效应强于服务业,且制造业的后端互动度比前端互动度有微弱优势,细分行业间的差异性显著。另外,相比发达地区,陕西省两产业间的互动度较弱。

Determination of α-glucosidase inhibitors from Scutellaria baicalensis using liquid chromatography with quadrupole time of flight tandem mass spectrometry coupled with centrifugal ultrafiltration

The present study aimed at identifying potential lead compounds for diabetes mellitus drug discovery. We developed a novel method involving centrifugal ultrafiltration separation subsequent liquid chromatography with quadrupole time of flight tandem mass spectrometry(LC-Q/TOF-MS/MS) determination to screen α-glucosidase inhibitors in complex Scutellaria baicalensis Georgi(SBG) extract. By adding a second filter to the screening process, the level of non-specific binding of Compounds 1, 3, 10 and 11 was significantly decreased, and the level of non-specific binding of Compounds 5 and 15 also was reduced. As a result, five flavonoids identified as baicalein, baicalein, wogonin, chrysin, and oroxylin A, were rapidly found to interact with α-glucosidase and possess potent anti-α-glucosidase activity in vitro. Specific binding of ligands to α-glucosidase was demonstrated though the proposed method and the ligands could be ranked in order of affinity for α-glucosidase, which were corresponded to the order of inhibitory activity in vitro. In conclusion, our results indicated that the developed method is a rapid and effective screening method for rat intestinal α-glucosidase inhibitors from complex herbal medicines such as SBG.

生产性服务业与制造业互动影响的比较研究

评述生产性服务业和制造业两产业互动理论,梳理陕西两产业发展过程中存在的问题,对其关联程度进行投入产出比较实证分析。发现陕西两产业互动程度较弱,细分产业之间的互动程度存在较大差异。交通运输仓储及邮政业、金融业互动水平较高;房地产、科研技术服务互动程度较弱;科研和技术服务的影响力系数较高。

A lignin glycoside and a nortriterpenoid from Kadsura coccinea

AIM: To study the chemical constituents of the roots and stem bark of Kadsura coccinea. METHOD: Compounds were isolated by column chromatography on silica gel and Sephadex LH-20, and finally purified by prep-HPLC. Their structures were elucidated by extensive spectroscopic methods, including 1D- and 2D-NMR, and HR-ESI-MS. RESULTS: Two compounds were determined as(7′S,8′S,8R)-(8β,8′α)- dimethyl-4,4′-dihydroxy-5,3′-dimethoxy-5′-cyclolignan glucoside(1) and micrandiactone H(2), respectively. CONCLUSION: Compunds 1 and 2 are new and neither showed inhibitory effects on nitric oxide(NO) production in lipopolysaccharide-induced RAW264.7 macrophages.

Polyphyllin I promotes cell death via suppressing UPR-mediated CHOP ubiquitination and degradation in non-small cell lung cancer

Polyphyllin I(PPI)purified from Polyphylla rhizomes displays puissant cytotoxicity in many kinds of cancers.Several researches investigated its anti-cancer activity.But novel mechanisms are still worth investigation.This study aimed to explore PPI-induced endoplasmic reticulum(ER)stress as well as the underlying mechanism in non-small cell lung cancer(NSCLC).Cell viability or colony-forming was detected by MTT or crystal violet respectively.Cell cycle,apoptosis,reactive oxygen species(ROS)and mitochondrial membrane potential were assessed by flow cytometry.Gene and protein levels were evaluated by q RT-PCR and immunoblotting respectively.Protein interaction was determined by immunoprecipitation or immunofluorescence assay.Gene overexpression or silencing was carried out by transient transfection with plasmids or small interfering RNAs.The Cancer Genome Atlas(TCGA)database was used for Gene Set Enrichment Analysis(GSEA),survival analysis,gene expression statistics or pathway enrichment assay.PPI inhibited the propagation of NSCLC cells,increased non-viable apoptotic cells,arrested cell cycle at G2/M phase,induced ROS levels but failed to decrease mitochondrial membrane potential.High levels of GRP78 indicates poor prognosis in NSCLC patients.PPI selectively suppressed unfolded protein response(UPR)-induced GRP78 expression,subsequently protected CHOP from GRP78-mediated ubiquitination and degradation.We demonstrated that the natural product PPI,obtained from traditional herbal medicine,deserves for further study as a valuable candidate for lead compound in the chemotherapy of NSCLC.

Reversal of multidrug resistance by icaritin in doxorubicin-resistant human osteosarcoma cells

Multidrug resistance(MDR) is one of the major obstacles in cancer chemotherapy. Our previous study has shown that icariin could reverse MDR in MG-63 doxorubicin-resistant(MG-63/DOX) cells. It is reported that icariin is usually metabolized to icariside II and icaritin. Herein, we investigated the effects of icariin, icariside Ⅱ, and icaritin(ICT) on reversing MDR in MG-63/DOX cells. Among these compounds, ICT exhibited strongest effect and showed no obvious cytotoxicity effect on both MG-63 and MG-63/DOX cells ranging from 1 to 10 μmol·L^(-1). Furthermore, ICT increased accumulation of rhodamine 123 and 6-carboxyfluorescein diacetate and enhanced DOX-induced apoptosis in MG-63/DOX cells in a dose-dependent manner. Further studies demonstrated that ICT decreased the m RNA and protein levels of multidrug resistance protein 1(MDR1) and multidrug resistance-associated protein 1(MRP1). We also verified that blockade of STAT3 phosphorylation was involved in the reversal effect of multidrug resistance in MG-63/DOX cells. Taken together, these results indicated that ICT may be a potential candidate in chemotherapy for osteosarcoma.

Two new phenolic glycosides isolated from Ginkgo seeds

Two new phenolic glycosides, 7S, 8R-urolignoside-9′-O-β-D-glucoside(1) and scrophenoside G(2), were isolated and identified from the seeds of Ginkgo biloba L., a famous traditional medicine and functional food around the world. Their structures were elucidated by spectroscopic methods(1D and 2D NMR, HR-ESI-MS, and CD), and the comparisons of spectroscopic data with the reported values in the literature.

Type B polycyclic polyprenylated acylphloroglucinols from the roots of Hypericum beanii

Two new type B polycyclic polyprenylated acylphloroglucinols(PPAPs)(1 and 2)and a known biogenetic precursor hyperbeanol Q(3)were isolated from the root extract of Hypericum beanii,a medicinal plant widespread in southwest China.Their chemical structures were elucidated by 1 D/2 D NMR and HRESIMS data analysis,and absolute configurations were determined through detailed electric circular dichroism(ECD)analysis including ECD exciton chirality,Mo2(OAc)4-induced ECD,and ECD comparison.Of these compounds,hyperbeone A(1)is a typical[3.3.1]-type B PPAP with an unusual C-1 geranyl side chain,and hyperberin C(2)possesses a rare bicyclo[5.3.1]hendecane core.Taking compound 3 as a starting point,a plausible biosynthetic pathway to the bicyclic type B frameworks of 1 and 2 was proposed.

Two new phragmalin-type limonoids orthoesters from Entandrophragma candollei

Two new phragmalin-type limonoids orthoesters, encandollens A and B(1 and 2), were isolated from the stem barks of Entandrophragma candollei collected in Ghana. The structures of these compounds were elucidated on the basis of HR-ESI-MS, ~1 H and ^(13) C NMR, HSQC, HMBC, and ROESY data. Compound 1 was a rare C-15 enolic acyl phragmalin-type limonoid orthoester. Compounds 1 and 2 exhibited weak inhibitory effects on NO production in lipopolysaccharide(LPS)-induced RAW 264.7 cells.

Triterpenes from the stem bark of Mitragyna diversifolia and their cytotoxic activity

AIM: To study the chemical constituents and bioactivity of the stem bark of Mitragyna diversifolia. METHOD: Compounds were isolated by various chromatographic methods. Their structures were elucidated on the basis of spectroscopic techniques(IR, UV, MS, and NMR), and they were evaluated for their cytotoxic activities by the MTT method. RESULTS: Eight triterpenes were isolated and identified as 3α, 6β, 19α-trihydroxy-urs-12-en-28-oic acid(1), 3β, 6β, 19α- trihydroxy-urs-12-en-28-oic acid(2), 3-oxo-6β-19α-dihydroxy-urs-12-en-28-oic acid(3), 3β, 6β, 19α-trihydroxy-urs-12-en-24, 28-dioic acid 24-methyl ester(4), 3β, 6β, 19α, 24-tetrahydroxy-urs-12-en-28-oic acid(5), rotundic acid(6), 23-nor-24-exomethylene- 3β, 6β, 19α-trihydroxy-urs-12-en-28-oic acid(7), and pololic acid(8), respectively. All of the isolates were tested against two human tumor cell lines, MCF-7(breast) and HT-29(colon). CONCLUSION: Compound 1 was a new triterpene. Compounds 5-7 exhibited potent inhibitory effects on the growth of MCF-7 and HT-29 cells, and the others showed no cytotoxicity.

A new Lycopodium alkaloid from Phlegmariurus fargesii

AIM: To investigate the chemical constituents from the whole plants of Phlegmariurus fargesii. METHOD: Compounds were isolated by repeated silica gel column chromatography. Their structures were elucidated by spectroscopic methods and chemical correlation. The acetylcholinesterase(AChE) inhibitory activity of the isolated compounds was evaluated. RESULTS: A new Lycopodium alkaloid, lycopodine N-oxide(1), along with lycopodine(2), 8,15-dehydrolycopodine(3), 6α-hydroxylycopodine(4), deacetyllycoclavine(5), N-methylhuperzine B(6), lycodine(7), and phlegmarine(8), was isolated. CONCLUSION: Compound 1 is a new Lycopodium alkaloid, and compound 3 was obtained from nature for the first time. Other alkaloids are isolated from this plant for the first time.

Study on the mechanism of Wuzi-Yanzong-Wan-medicated serum interfering with the mitochondrial permeability transition pore in the GC-2 cell induced by atractyloside

Wuzi-Yanzong-Wan(WZYZW)is a classic prescription for male infertility.Our previous investigation has demon-strated that it can inhibit sperm apoplosis via afecting mitochondria,but the underlying mechanisms are unclear.The purpose of the present study was to explore the actions of WZYZW on mitochondrial permeability transition pore(mPTP)in mouse spermatocyte cell line(GC-2 cells)opened by atractyloside(ATR).At first,WZYZW-mediated serum was prepared from rats following oral adminis-tration of WZYZW for 7 days.GC-2 cells were divided into control group,model group,positive group,as well as 5%,10%,15%WZYZW-medicated serum group.Cyclosporine A(CsA)was used as a positive control.50 μmol·L^(-1) ATR was added afer drugs in-cubation.Cell viability was asessed using CCK-8.Apoptosis was detected using flow cytometry and TUNEL method.The opening of mPTP and mitochondrial membrane potential(MMP)were dected by Calcein AM and JC-1 fuorescent probe respectively.The mRNA and protein levels of voltage-dependent anion channel I(VDACI),cyelophilin D(CypD),adenine nucleide translocator(ANT),cytochrome C(Cyt C),caspase 3,9 were dected by RT-PCR(real time quantity PCR)and Western blotting respectively.The results demonstrated that mPTP of GC-2 cells was opened alpter 24 hours of ATR treatment,resulting in decreased MMP and increased apoptosis.Pre-protection with WZYZ-medicated serum and CsA inhibited the opening of mPTP of GC-2 cells induced by ATR associ ated with increased MMP and decreased apoptosis.Morcover,the results of RT-qPCR and WB suggested that WZYZW-medicated serum could significantly reduce the mRNA and protein levels of VDACI and CypD,Caspase-3,9 and CylC,as well as a increased ra-tio of BclBax.However,ANT was not significantly ffected.Therefore,these findings indicated that WZYZW inhibited mitochondri-al mediated apoptosis by atenuating the opening of mPTP in GC-2 cells.WZYZW-medicated serum inhibited the expressions of VDACI and CypD and increased the expression of Bcl-2,which afected the opening of mPTP and exerted protective and anti-apop-totic ffects on GC-2 cell induced by ATR.

Sesquiterpenoids from the leaves of Sarcandra glabra

Sarglanoids A-F,six new sesquiterpenoids belonging to eudesmane(1-5)and eremophilane(6)types,were isolated from the leaves of Sarcandra glabra,a famous traditional Chinese medicine(TCM).Their structures including absolute configurations were elucidated through extensive spectroscopic analysis and electronic circular dichroism(ECD)calculations.Compounds 1-2 were rare N-containing eudesmane-type sesquiterpenoids.Compound 3 exhibited inhibitory activity against nitric oxide(NO)production in lipopolysaccharides(LPS)-induced RAW 264.7 cells with IC_(50) values at 20.00±1.30μmol·L^(-1).These findings provide scientific evidence for sesquiterpenoids as the material foundation of S.glabra.

Highly oxygenous trichilin-type limonoids from Trichilia sinensis

Six new trichilin-type limonoids(1-6)with C-19/29 lactol or acetal bridge and a new ring intact limonoid(7)were isolated from the desiccative ripe fruits of Trichilia sinensis.Their structures were determined by extensive spectroscopic methods including 1 H NMR,13 C NMR,HSQC,HMBC,ROESY experiments as well as HRESI-MS data.All isolated compounds were evaluated for toxicities against human pulmonary carcinoma A549 and Hela cell lines by sulforhodamine B(SRB)method.Compound 7 showed weak inhibitory activity in Hela cell line at 40μmol·L^-1.