5-Demethylnobiletin and its major metabolites:efficient preparation and mechanism of their anti-proliferation activity in HepG2 cells

5-Demethylnobile tin(5-DMN),a hydroxylated polymethoxyflavone(OH-PMF)identified in aged citrus peels,has demonstrated health benefiting effects in previous studies.5-DMN undergoes biotransformation in vivo,yielding 5,3’-didemethylnobiletin(5,3’-DDMN),5,4’-didemethylnobiletin(5,4’-DDMN)and5,3’,4’-tridemethylnobiletin(5,3’,4’-TDMN).However,the anti-cancer effects of 5-DMN and its in vivo metabolites against HepG2 cells remain unclear.In this study,an efficient chemical synthetic method was developed to obtain 5-DMN and its 3 metabolites,and their molecular structures were confirmed by;H NMR and LC-MS.Cytotoxicity,cell cycle arrestment,apoptosis and caspase-3 expression were investigated to evaluate the anti-liver cancer effects of these OH-PMFs on HepG2 cells.The results showed that all 4 compounds inhibited the proliferation of HepG2 cells in a concentration-dependent manner.Their anti-proliferative activity was exerted through inducing G2/M phase arrestment,cell apoptosis and promoting expression of a key apoptotic protein called cleaved caspase-3.Our results indicated that 5,3’-DDMN and5,3’,4’-TDMN showed a stronger inhibitory activity on cell proliferation than 5-DMN,followed by 5,4’-DDMN.The expression of cleaved caspase-3 was the highest in cells treated with 5,4’-DDMN,implying that the apoptosis induced by other OH-PMFs might be mediated by other apoptotic execution proteins.Our research reveals the application potential and scientific evidence for the production and functionality of OH-PMFs.

Three-dimensional printing for heart diseases: clinical application review

Heart diseases remain the top threat to human health,and the treatment of heart diseases changes with each passing day.Convincing evidence shows that three-dimensional(3D)printing allows for a more precise understanding of the complex anatomy associated with various heart diseases.In addition,3D-printed models of cardiac diseases may serve as effective educational tools and for hands-on simulation of surgical interventions.We introduce examples of the clinical applications of different types of 3D printing based on specific cases and clinical application scenarios of 3D printing in treating heart diseases.We also discuss the limitations and clinically unmet needs of 3D printing in this context.

Analysis of isolation of cerebral cortical neurons in rats by different methods

The aim of this study was to find a way to efficiently separate neuronal cells from the cerebral cortex of adult rats,providing a reference method for rapid acquisition of neuronal cells from the adult rat brain.Fifteen SD rats were randomly divided into three groups,with five SD rats in each group.Then,neuron cells were isolated from the adult rat cerebral cortex by the grinding method,the trypsin method,and the collagenase II method,respectively.The expression of anti-NeuN in the neurons of each group was analyzed by flow cytometry.The acquisition rates and morphology of neurons of each group were observed by immunofluorescence staining.The grinding or collagenase II method is more suitable for rapid acquisition of neuronal cells from an adult rat’s cerebral cortex.The number of neuron cells obtained by the trypsin method were very few,so it is not convenient for later experiments.

High Mannose-Specific Aptamers for Broad-Spectrum Virus Inhibition and Cancer Targeting

High mannose oligosaccharides are characteristic and essential for immune evasion of many viruses and cancer cells.They are potential targets for viral inhibition and cancer diagnosis/therapy.Particularly,high mannose-binding reagents may be a unique asset for fighting the ongoing and mutating SARSCoV-2 virus.Lectins are prevailing reagents for saccharide binding but suffer from inadequate specificity and apparent immunogenicity.Meanwhile,other reagents for the same purpose,such as antibodies and aptamers,have rarely been reported.Herein,using molecularly imprinted magnetic nanoparticles as a potent platform,we report a smart selection method for fine screening of high mannose-specific aptamers.Monovalent aptamers were first effectively screened within eight rounds of selection.Multivalent aptamers,in the forms of dendritic polymer or tetrahedral DNA nanostructure(TDN),were further engineered.The aptamers exhibited high affinity toward the spike protein of SARS-CoV-2 and the envelope protein GP120 of HIV.Both the monovalent aptamer and its TDN form exhibited a certain inhibition effect to the SARS-CoV-2 pseudovirus.On the other hand,both the monovalent aptamer and its dendritic form permitted the recognition of cancer cells over normal cells.Therefore,as unprecedented reagents for broad-spectrum viral inhibition and cancer targeting,these aptamers hold great promise for clinical treatment and diagnosis.

Detection of Huanglongbing(citrus greening) based on hyperspectral image analysis and PCR

Huanglongbing (HLB, citrus greening) is one of the most serious quarantine diseases of citrus worldwide. To monitor in real-time, recognize diseased trees, and efficiently prevent and control HLB disease in citrus, it is necessary to develop a rapid diagnostic method to detect HLB infected plants without symptoms. This study used Newhall navel orange plants as the research subject, and collected normal color leaf samples and chlorotic leaf samples from a healthy orchard and an HLB-infected orchard, respectively. First, hyperspectral data of the upper and lower leaf surfaces were obtained, and then the polymerase chain reaction (PCR) was used to detect the HLB bacterium in each leaf. The PCR test results showed that all samples from the healthy orchard were negative, and a portion of the samples from the infected orchard were positive. According to these results, the leaf samples from the orchards were divided into disease-free leaves and HLB-positive leaves, and the least squares support vector machine recognition model was established based on the leaf hyperspectral reflectance. The effect on the model of the spectra obtained from the upper and lower leaf surfaces was investigated and different pretreatment methods were compared and analyzed. It was observed that the HLB recognition rate values of the calibration and validation sets based on upper leaf surface spectra under 9-point smoothing pretreatment were 100% and 92.5%, respectively. The recognition rate values based on lower leaf surface spectra under the second-order derivative pretreatment were also 100% and 92.5%, respectively. Both upper and lower leaf surface spectra were available for recognition of HLB-infected leaves, and the HLB PCR-positive leaves could be distinguished from the healthy by the hyperspectral modeling analysis. The results of this study show that early and nondestructive detection of HLBinfected leaves without symptoms is possible, which provides a basis for the hyperspectral diagnosis of citrus with HLB.

数字化转型、技术创新动态能力与企业绩效——来自中国装备制造上市企业的经验证据

数字化转型为企业提高资源配置效率、培育市场竞争优势提供了有力工具,是企业实现高质量发展的有效途径。文章利用2011~2019年沪深A股主板装备制造上市企业数据,从投入、产出和转化三个维度衡量企业技术创新动态能力,基于技术创新动态能力视角研究数字化转型对企业绩效的影响机制。研究发现,数字化转型对装备制造企业绩效具有显著正向影响,且这一促进作用能够被技术创新动态能力的渠道效应所捕获。进一步考察异质性发现,数字化转型对东部地区以及通用设备制造企业绩效的促进作用明显;非国有装备制造企业技术创新动态能力的渠道效应显著,但在国有企业中这一机制并不显著。研究结论对指导装备制造企业数字化转型实践、提升装备制造企业绩效具有重要借鉴意义。

中国装备制造业发展:特征事实与增长动力转换实证

在中国经济由高速增长阶段转向高质量发展阶段的现实背景下,支撑中国装备制造业保持稳定增长的传统动力受到供需两侧结构性变化的约束而趋于减弱,推动装备制造业增长动力转换对于实现装备制造业高质量发展具有重要意义。文章首先描述了1990~2017年中国装备制造业发展的特征事实,然后通过构建扩展的C-D生产函数模型,运用全面FGLS和迭代FGLS估计模型对中国装备制造业增长动力转换进行实证。研究结果表明:中国装备制造业各细分行业目前正处于或即将进入产业成熟期,亟须培育产业增长新动力。从整体回归结果看,中国装备制造业产出增长主要由劳动力要素驱动,资本要素和研发投入的驱动作用相对较弱。从分段回归结果看,劳动力要素和研发投入对装备制造业产出增长的驱动作用明显提升,而资本要素的驱动作用却明显减弱。中国装备制造业并未遵循"劳动力要素驱动-资本要素驱动-研发投入驱动"的传统增长路径,而是存在着依靠劳动力要素和研发投入"双轮驱动"的可能性。

IL-6/STAT3报告基因系统的构建及抑制IL-6/STAT3信号通路的中药单体的筛选及验证

寻找可抑制IL-6/STAT3信号通路的活化从而抑制肿瘤的生长和恶化的中药单体化合物具有重要意义及发展前景。文中通过基因重组技术构建出一种含有STAT3增强子序列和NanoLuc(NLuc)报告基因序列的新表达载体,并进一步建立受STAT3调控并稳定表达NLuc荧光素酶的细胞系,利用该细胞系定量检测多种中药单体化合物对IL-6/STAT3信号通路的调控作用,并对抑制IL-6/STAT3信号通路的中药单体的效果进行验证。酶切鉴定及测序结果表明报告基因表达载体pQCXIP-STAT3-NLuc构建成功。STAT3转录因子的刺激物白细胞介素-6(IL-6)作用于所构建的稳定表达NLuc的细胞系后出现特异性荧光素酶反应,且作用效果呈良好的剂量依赖性,表明受STAT3调控稳定表达NLuc荧光素酶的细胞系构建成功。Western blotting及Real-time PCR实验结果表明所筛选的中药单体化合物石斛碱及粉防己碱可抑制IL-6/STAT3信号通路并显著下调其下游基因Bcl-2及Bcl-x的表达,且作用呈剂量依赖性。综上所述,文中构建了可高效检测STAT3转录活性的报告基因系统,并利用该系统成功地筛选出可抑制IL-6/STAT3信号通路的中药单体化合物,具有一定的理论和应用价值。

HBc-VLP的分子动力学模拟和结合自由能计算

乙型肝炎核心病毒样颗粒HBc-VLPs(Hepatitis B Core Antigen Virus-like Particles)因稳定性好且易于改造,被作为疫苗载体广泛使用,但影响VLPs稳定性的控制机制尚不清楚。采用分子动力学模拟研究了HBc-VLP中蛋白亚基二聚体、五聚体及六聚体复合物的稳定性,计算了体系中蛋白亚基的介电常数,避免了以往研究中直接使用经验参数的做法;通过分子力学-泊松玻尔兹曼溶剂可及表面积(MM-PBSA)方法计算亚基分子间的结合自由能,表明范德华作用能和非极性溶剂化作用能有利于促进相邻蛋白亚基间的亲和作用;根据计算结果可推测HBc-VLPs中六聚体比五聚体的稳定性更强,而两个六聚体之间或五聚体同六聚体之间形成的二聚体有助于进一步形成结构更加稳定的HBc-VLPs。该结论有助于生物工程中对HBc-VLPs的蛋白质改造,从而提高HBc-VLPs为载体的候选疫苗的稳定性。

Application of cardiovascular 3-dimensional printing in Transcatheter aortic valve replacement

Transcatheter aortic valve replacement(TAVR)has been performed for nearly 20years,with reliable safety and efficacy in moderate-to high-risk patients with aortic stenosis or regurgitation,with the advantage of less trauma and better prognosis than traditional open surgery.However,because surgeons have not been able to obtain a full view of the aortic root,3-dimensional printing has been used to reconstruct the aortic root so that they could clearly and intui-tively understand the specific anatomical structure.In addition,the 3D printed model has been used for the in vitro simulation of the planned procedures to predict the potential complications of TAVR,the goal being to provide guidance to reasonably plan the procedure to achieve the best outcome.Postprocedural 3D printing can be used to understand the depth,shape,and distribution of the stent.Cardiovascular 3D printing has achieved remarkable results in TAVR and has a great potential.

Rapid detection of chlorophyll content and distribution in citrus orchards based on low-altitude remote sensing and bio-sensors

The accuracy of detecting the chlorophyll content in the canopy and leaves of citrus plants based on sensors with different scales and prediction models was investigated for the establishment of an easy and highly-efficient real-time nutrition diagnosis technology in citrus orchards.The fluorescent values of leaves and canopy based on the Multiplex 3.6 sensor,canopy hyperspectral reflectance data based on the FieldSpec4 radiometer and spectral reflectance based on low-altitude multispectral remote sensing were collected from leaves of Shatang mandarin and then analyzed.Additionally,the associations of the leaf SPAD(soil and plant analyzer development)value with the ratio vegetation index(RVI)and normalized differential vegetation index(NDVI)were analyzed.The leaf SPAD value predictive model was established by means of univariate and multiple linear regressions and the partial least squares method.Variable distribution maps of the relative canopy chlorophyll content based on spectral reflectance in the orchard were automatically created.The results showed that the correlations of the SPAD values obtained from the Multiplex 3.6 sensor,FieldSpec4 radiometer and low-altitude multispectral remote sensing were highly significant.The measures of goodness of fit of the predictive models were R^(2)=0.7063,RMSECV=3.7892,RE=5.96%,and RMSEP=3.7760 based on RVI_((570/800)) and R^(2)=0.7343,RMSECV=3.6535,RE=5.49%,and RMSEP=3.3578 based on NDVI[(570,800)(570,950)(700,840)].The technique to create spatial distribution maps of the relative canopy chlorophyll content in the orchard was established based on sensor information that directly reflected the chlorophyll content of the plants in different parts of the orchard,which in turn provides evidence for implementation of orchard productivity evaluation and precision in fertilization management.