Potassium and calcium channels in different nerve cells act as therapeutic targets in neurological disorders

The central nervous system, information integration center of the body, is mainly composed of neurons and glial cells. The neuron is one of the most basic and important structural and functional units of the central nervous system, with sensory stimulation and excitation conduction functions. Astrocytes and microglia belong to the glial cell family, which is the main source of cytokines and represents the main defense system of the central nervous system. Nerve cells undergo neurotransmission or gliotransmission, which regulates neuronal activity via the ion channels, receptors, or transporters expressed on nerve cell membranes. Ion channels, composed of large transmembrane proteins, play crucial roles in maintaining nerve cell homeostasis. These channels are also important for control of the membrane potential and in the secretion of neurotransmitters. A variety of cellular functions and life activities, including functional regulation of the central nervous system, the generation and conduction of nerve excitation, the occurrence of receptor potential, heart pulsation, smooth muscle peristalsis, skeletal muscle contraction, and hormone secretion, are closely related to ion channels associated with passive transmembrane transport. Two types of ion channels in the central nervous system, potassium channels and calcium channels, are closely related to various neurological disorders, including Alzheimer's disease, Parkinson's disease, and epilepsy. Accordingly, various drugs that can affect these ion channels have been explored deeply to provide new directions for the treatment of these neurological disorders. In this review, we focus on the functions of potassium and calcium ion channels in different nerve cells and their involvement in neurological disorders such as Parkinson's disease, Alzheimer's disease, depression, epilepsy, autism, and rare disorders. We also describe several clinical drugs that target potassium or calcium channels in nerve cells and could be used to treat these disorders. We concluded that there are few clinical drugs that can improve the pathology these diseases by acting on potassium or calcium ions. Although a few novel ion-channelspecific modulators have been discovered, meaningful therapies have largely not yet been realized. The lack of target-specific drugs, their requirement to cross the blood–brain barrier, and their exact underlying mechanisms all need further attention. This review aims to explain the urgent problems that need research progress and provide comprehensive information aiming to arouse the research community's interest in the development of ion channel-targeting drugs and the identification of new therapeutic targets for that can increase the cure rate of nervous system diseases and reduce the occurrence of adverse reactions in other systems.

Magnesium fertilizer application increases peanut growth and pod yield under reduced nitrogen application in southern China

This study investigated the effect of magnesium application on peanut growth and yield under two nitrogen(N)application rates in acidic soil in southern China.The chlorophyll content,net photosynthetic rate and dry matter accumulation of the N-sensitive cultivar decreased under reduced N treatments,whereas no effect was observed on the relevant indicators in the N-insensitive variety GH1026.Mg application increased the net photosynthetic rate by increasing the expression of genes involved in chlorophyll synthesis and Rubisco activity in the leaves during the pegging stage under 50%N treatment,while no effect on the net photosynthetic rate was observed under the 100%N treatment.The rate of dry matter accumulation at the early growth stage,total dry matter accumulation and pod yield at harvest increased after Mg application under 50%N treatment by increasing the transportation of assimilates from stems and leaves to pods in both peanut varieties,whereas no effect was found under 100%N treatment.Moreover,Mg application increased the NUE under 50%N treatment.No improvement of NUE in either peanut variety was found under 100%N treatment,while Mg application under the 50%N treatment can obtain a higher economic benefit than the 100%N treatment.In acidic soil,application of 307.5 kg ha^(-1)of Mg sulfate fertilizer under 50%reduced nitrogen application is a suitable fertilizer management measure for improving carbon assimilation,NUE and achieve high peanut yields in southern China.

Model-Free Feature Screening via Maximal Information Coefficient (MIC) for Ultrahigh-Dimensional Multiclass Classification

It is common for datasets to contain both categorical and continuous variables. However, many feature screening methods designed for high-dimensional classification assume that the variables are continuous. This limits the applicability of existing methods in handling this complex scenario. To address this issue, we propose a model-free feature screening approach for ultra-high-dimensional multi-classification that can handle both categorical and continuous variables. Our proposed feature screening method utilizes the Maximal Information Coefficient to assess the predictive power of the variables. By satisfying certain regularity conditions, we have proven that our screening procedure possesses the sure screening property and ranking consistency properties. To validate the effectiveness of our approach, we conduct simulation studies and provide real data analysis examples to demonstrate its performance in finite samples. In summary, our proposed method offers a solution for effectively screening features in ultra-high-dimensional datasets with a mixture of categorical and continuous covariates.

Flexible Large-Area Graphene Films of 50-600 nm Thickness with High Carrier Mobility

Bulk graphene nanofilms feature fast electronic and phonon transport in combination with strong light-matter interaction and thus have great potential for versatile applications,spanning from photonic,electronic,and optoelectronic devices to charge-stripping and electromagnetic shielding,etc.However,large-area flexible close-stacked graphene nanofilms with a wide thickness range have yet to be reported.Here,we report a polyacrylonitrile-assisted’substrate replacement’strategy to fabricate large-area free-standing graphene oxide/polyacrylonitrile nanofilms(lateral size~20 cm).Linear polyacrylonitrile chains-derived nanochannels promote the escape of gases and enable macro-assembled graphene nanofilms(nMAGs)of 50-600 nm thickness following heat treatment at 3,000℃.The uniform nMAGs exhibit 802-1,540 cm^(2)V-1s-1carrier mobility,4.3-4.7 ps carrier lifetime,and>1,581 W m^(-1)K^(-1)thermal conductivity(n MAG-assembled 10μm-thick films,mMAGs).nMAGs are highly flexible and show no structure damage even after 1.0×10^(5)cycles of folding-unfolding.Furthermore,n MAGs broaden the detection region of graphene/silicon heterojunction from near-infrared to mid-infrared and demonstrate higher absolute electromagnetic interference(EMI)shielding effectiveness than state-of-the-art EMI materials of the same thickness.These results are expected to lead to the broad applications of such bulk nanofilms,especially as micro/nanoelectronic and optoelectronic platforms.

氮素调控花生共生结瘤的机制研究进展

氮是花生生长发育所需的大量元素,共生结瘤固氮是花生获取氮素的主要方式之一。花生共生结瘤固氮涉及复杂的调控机理,揭示氮素对根瘤固氮的调控机制对发挥生物固氮潜力具有重要意义。本文系统总结了花生根瘤形成的“裂隙侵染”机制、花生共生结瘤和数量调控的机制以及氮素影响花生结瘤的调控机制。目前,氮素影响慢生根瘤菌与花生互作进而调控结瘤的分子机理尚不清楚,因此未来的研究重点应该集中在氮素影响花生慢生根瘤菌与花生的信号交流、根瘤数调节和营养交换机制等方面,为提高花生结瘤固氮效率和产量、减少化学氮肥施用提供理论基础。

Effects of mixed fertilizers formed by the compounding of two targeted controlled-release nitrogen fertilizers on yield,nitrogen use efficiency,and ammonia volatilization in double-cropping rice

One-time application of mixed fertilizer formed by the compounding of two controlled-release nitrogen fertilizers(CRUs)with targeted N supply during the periods from transplantation(TS)to panicle initiation(PI)and from PI to heading(HS)is expected to synchronize the double-peak N demand of rice.However,its effects on the yield and N use efficiency(NUE)of labor-intensive double-cropping rice were unknown.Two targeted CRU(CRU_(A)and CRU_(B))were compounded in five ratios(CRU_(A):CRU_(B)=10:0,7:3,5:5,3:7,and 0:10)to form five mixed fertilizers(BBFs):BBF1-5.A field experiment was performed to investigate the characteristics of N supply in early and late seasons under different BBFs and their effects on N uptake,yield,and ammonia volatilization(AV)loss from paddy fields of double-cropping rice.Conventional high-yield fertilization(CK,three split applications of urea)and zero-N treatments were established as controls.The N supply dropped significantly with the increased compound ratio of CRU_(B)during the period from TS to PI,but increased during the period from PI to HS.With the exception of the period from TS to PI in the late rice season,the N uptake of early and late rice maintained close synchronicity with the N supply of BBFs during the double-peak periods.Excessive N supply(BBF1 and BBF2)in the late rice season during the period from TS to PI increased N loss by AV.The effect of BBF on grain yield increase varied widely between seasons,irrespective of year.Among the BBFs,the BBF2 treatment of early rice not only stabilized the spikelets per panicle but also ensured a high number of effective panicles by promoting N uptake during the period from TS to PI and a high grain-filling percentage by appropriately reducing the N supply at the later PI stage,resulting in the highest rice yield.While stabilizing the effective panicle number,the BBF4 treatment of late rice increased the number of spikelets per panicle by promoting N uptake during the period from PI to HS,resulting in the highest rice yield.The two-year average yield and apparent N recovery efficiency of the BBF2 treatment during the early rice season were 9.6 t ha 1 and 45.3%,while those of late rice in BBF4 were 9.6 t ha 1 and 43.0%,respectively.The yield and NUE indexes of BBF2 in early rice and BBF4 in late rice showed no significant difference from those of CK.The AVs of BBF2 during the early rice season and of BBF4 during the late rice season were 50.0%and 76.8%lower,respectively,than those of CK.BBF2 and BBF4 could effectively replace conventional urea split fertilization in early and late rice seasons,ensuring rice yield and NUE and reducing AV loss in paddy fields.

Haem Oxygenase 1 is a potential target for creating etiolated/albino tea plants (Camellia sinensis) with high theanine accumulation

Theanine content is highly correlated with sensory quality and health benefits of tea infusion.The tender shoots of etiolated and albino tea plants contain higher theanine than the normal green tea plants and are valuable materials for high quality green tea processing.However,why these etiolated or albino tea plants can highly accumulate theanine is largely unknown.In this study,we observed an Arabidopsis etiolated mutant hy1–100(mutation in Haem Oxygenase 1,HO1)that accumulated higher levels of glutamine(an analog of theanine).We therefore identified CsHO1 in tea plants and found CsHO1 is conserved in amino acid sequences and subcellular localization with its homologs in other plants.Importantly,CsHO1 expression in the new shoots was much lower in an etiolated tea plants‘Huangkui’and an albino tea plant‘Huangshan Baicha’than that in normal green tea plants.The expression levels of CsHO1 were negatively correlated with theanine contents in these green,etiolated and albino shoots.Moreover,CsHO1 expression levels in various organs and different time points were also negatively correlated with theanine accumulation.The hy1–100 was hypersensitive to high levels of theanine and accumulated more theanine under theanine feeding,and these phenotypes were rescued by the expression of CsHO1 in this mutant.Transient knockdown CsHO1 expression in the new shoots of tea plant using antisense oligonucleotides(asODN)increased theanine accumulation.Collectively,these results demonstrated CsHO1 negatively regulates theanine accumulation in tea plants,and that low expression CsHO1 likely contributes to the theanine accumulation in etiolated/albino tea plants.

Theanine, a tea-plant-specific non-proteinogenic amino acid, is involved in the regulation of lateral root development in response to nitrogen status

Glutamine synthetase type I(GSI)-like proteins are proposed to mediate nitrogen signaling and developmental fate by synthesizing yet unidentified metabolites.Theanine,the most abundant non-proteinogenic amino acid in tea plants,is the first identified metabolite synthesized by a GSI-like protein(CsTSI)in a living system.However,the roles of theanine in nitrogen signaling and development are little understood.In this study we found that nitrogen deficiency significantly reduced theanine accumulation and increased lateral root development in tea plant seedlings.Exogenous theanine feeding significantly repressed lateral root development of seedlings of tea plants and the model plant Arabidopsis.The transcriptomic analysis revealed that the differentially expressed genes in the roots under theanine feeding were enriched in the apoplastic pathway and H2O_(2) metabolism.Consistently,theanine feeding reduced H2O_(2) levels in the roots.Importantly,when co-treated with H2O_(2),theanine abolished the promoting effect of H2O_(2) on lateral root development in both tea plant and Arabidopsis seedlings.The results of histochemical assays confirmed that theanine inhibited reactive oxygen species accumulation in the roots.Further transcriptomic analyses suggested the expression of genes encoding enzymes involved in H2O_(2) generation and scavenging was down-and upregulated by theanine,respectively.Moreover,the expression of genes involved in auxin metabolism and signaling,cell division,and cell expansion was also regulated by theanine.Collectively,these results suggested that CsTSI-synthesized theanine is likely involved in the regulation of lateral root development,via modulating H2O_(2) accumulation,in response to nitrogen levels in tea plants.This study also implied that the module consisting of GSI-like protein and theanine-like metabolite is probably conserved in regulating development in response to nitrogen status in plant species.

THE RIEMANN PROBLEM WITH DELTA INITIAL DATA FOR THE NON-ISENTROPIC IMPROVED AW-RASCLE-ZHANG MODEL

In this paper,we study the Radon measure initial value problem for the nonisentropic improved Aw-Rascle-Zhang model.For arbitrary convex F(u)in this model we construct the Riemann solutions by elementary waves andδ-shock waves using the method of generalized characteristic analysis.We obtain the solutions constructively for initial data containing the Dirac measure by taking the limit of the solutions for that with three piecewise constants.Moreover,we analyze different kinds of wave interactions,including the interactions of theδ-shock waves with elementary waves.

CsGDH2.1 negatively regulates theanine accumulation in late-spring tea plants (Camellia sinensis var. sinensis)

Theanine,a unique and the most abundant non-proteinogenic amino acid in tea plants,endows tea infusion with the umami taste and anti-stress effects.Its content in tea correlates highly with green tea quality.Theanine content in new shoots of tea plants is high in mid-spring and greatly decreases in late spring.However,how the decrease is regulated is largely unknown.In a genetic screening,we observed that a yeast mutant,glutamate dehydrolase 2(gdh2),was hypersensitive to 40 mM theanine and accumulated more theanine.This result implied a role of CsGDH2s in theanine accumulation in tea plants.Therefore,we identified the two homologs of GDH2,CsGDH2.1 and CsGDH2.2,in tea plants.Yeast complementation assay showed that the expression of CsGDH2.1 in yeast gdh2 mutant rescued the theanine hypersensitivity and hyperaccumulation of this mutant.Subcellular localization and tissue-specific expression showed CsGDH2.1 localized in the mitochondria and highly expressed in young tissues.Importantly,CsGDH2.1 expression was low in early spring,and increased significantly in late spring,in the new shoots of tea plants.These results all support the idea that CsGDH2.1 regulates theanine accumulation in the new shoots.Moreover,the in vitro enzyme assay showed that CsGDH2.1 had glutamate catabolic activity,and knockdown of CsGDH2.1 expression increased glutamate and theanine accumulation in the new shoots of tea plants.These findings suggested that CsGDH2.1-mediated glutamate catabolism negatively regulates theanine accumulation in the new shoots in late spring,and provides a functional gene for improving late-spring green tea quality.

GSA:组学原始数据归档库

生命科学的发展已进入组学大数据时代,然而我国至今尚未形成公共数据库存储体系。为弥补国内空白,组学原始数据归档库(Genome Sequence Archive, GSA, http://bigd.big.ac.cn/gsa)系统遵循国际核苷酸序列数据联盟(International Nucleotide Sequence Database Collaboration,INSDC)相关数据库建设标准,广泛收集各类生命组学原始数据。自2015年底上线运行以来,已获得了包括Cell、Nature、PNAS、GPB等30余个国内外期刊的认可,收录的数据量呈显著增长趋势,提供的数据服务受到国内外广大科研人员的认可。GSA有效缓解了当前我国生命组学数据汇交、存储与共享困难的问题,为我国国家生物信息中心的建设奠定了坚实基础。本文对目前GSA数据汇交、审核、发布与管理等机制进行了深入阐述,以方便用户了解GSA的各项功能,提供更高效的数据服务。

研究生现代光谱分析课程的教学改革探索与实践

在现代光谱分析研究生课程的教学中,围绕综合素质能力培养,不断探索课程建设与教学改革的有效措施:(1)教学内容与时俱进,体现课程的科学性和前沿性;(2)围绕立德树人目标设计课程思政案例,加强“三观”价值引领;(3)探索翻转课堂教学、项目式教学,运用智慧教学工具管理教学过程,构建多元化考核评价体系。

GSA-Human:人类遗传资源数据管理的公共系统

GSA-Human是人类遗传资源数据汇交、存储、管理与共享的数据库系统,可提供人类遗传资源数据的上传、下载、浏览、检索等公共服务,并有效支撑了国家重点研发计划科技项目数据的汇交与管理工作。系统具有符合《中华人民共和国人类遗传资源管理条例》数据安全管理策略,提供公开访问和受控访问相结合的数据使用模式。公开访问数据允许用户自由下载与获取;受控访问数据采用申请-审核的模式,即需要通过数据管理委员会(Data Access Committee,DAC)的授权方可获得下载和使用权限。系统自上线以来,截至2021年7月,汇集数据总量已超5.27 PB。

CD103阳性肿瘤浸润淋巴细胞与卵巢高级别浆液性癌患者预后关系的研究

目的:评估CD103阳性(CD103+)肿瘤浸润淋巴细胞(tumor-infiltrating lymphocyte,TIL)在实施初次肿瘤减灭术(debulking surgery,PDS)与新辅助化疗(neoadjuvant chemotherapy,NACT)的卵巢高级别浆液性癌(high-grade serous ovarian carcinoma,HGSC)患者中分布、表达差异与临床病理特征及预后的关系。方法:收集2018年6月至2019年6月四川大学华西第二医院收治的137例HGSC患者的临床病理资料,将患者石蜡组织标本制成组织芯片,分为PDS组83例和NACT组54例。采用免疫组织化学法和免疫荧光共染法观察CD103+TIL与CD8阳性(CD8+)、CD4阳性(CD4+)TIL的关系,并采用相应的统计学方法分析CD103+TIL与患者治疗、预后的关系。结果:采用χ^(2)检验显示,NACT组CD103+TIL、CD8+TIL表达均高于PDS组(P=0.026、P=0.029),且CD103+TIL、CD8+TIL与化疗敏感性具有显著性相关(P=0.03、P=0.018),两组患者CD4+TIL与所有临床病理特征均无显著性相关(P>0.05)。Spearman相关性检验显示,CD103+TIL与CD8+TIL具有显著性相关(P<0.01)。免疫组织化学法和免疫荧光共染法结果显示,CD103+TIL实际多为CD8+TIL。单因素及Cox比例风险回归模型多因素生存分析发现,仅在肿瘤上皮内CD103+TIL、CD8+TIL的表达具有预后意义,是HGSC的独立预后因素(P<0.05)。结论:HGSC患者CD103+TIL主要分布于肿瘤上皮内,是免疫活性更高的CD8+TIL亚群,因此CD103+TIL较CD8+TIL可更好地预测患者预后。

Agronomic performance of drought-resistance rice cultivars grown under alternate wetting and drying irrigation management in southeast China

Compared to drought-susceptible rice cultivars(DSRs),drought-resistance rice cultivars(DRRs)could drastically reduce the amount of irrigation water input and simultaneously result in higher grain yield under water-saving irrigation conditions.However,the mechanisms underlying these properties are unclear.We investigated how improved agronomic traits contribute to higher yield and higher water use efficiency(WUE)in DRRs than in DSRs under alternate wetting and drying(AWD).Two DRRs and two DSRs were field-grown in 2015 and 2016 using two different irrigation regimes:continuous flooding(CF)and AWD.Under CF,no statistical differences in grain yield and WUE were observed between DRRs and DSRs.Irrigation water under the AWD regime was 275–349 mm,an amount 49.8%–56.2% of that(552–620 mm)applied under the CF regime.Compared to CF,AWD significantly decreased grain yield in both DRRs and DSRs,with a more significant reduction in DSRs,and WUE was increased in DRRs,but not in DSRs,by 9.9%–23.0% under AWD.Under AWD,DRRs showed a 20.2%–26.2% increase in grain yield and an 18.6%–24.5% increase in WUE compared to DSRs.Compared to DSRs,DRRs showed less redundant vegetative growth,greater sink capacity,higher grain filling efficiency,larger root biomass,and deeper root distribution under AWD.We conclude that these improved agronomic traits exert positive influences on WUE in DRRs under AWD.

Intranasal delivery of paeoniflorin nanocrystals for brain targeting

Paeoniflorin(PA) is an anti-Parkinson Chinese medicine with inferior bioavailability and difficulty in delivery to the brain. This research is to develop an efficacious PA nanocrystal formulation(PA-NCs) that is suitable for intranasal administration to treat Parkinson’s disease(PD). PA-NCs were fabricated through an antisolvent precipitation method using TPGS as the stabilizer. The rod-shaped PA-NCs had particle size of 139.6 ± 1.3 nm and zeta potential of-23.2 ± 0.529 mV. A molecular dynamics simulation indicated that van der Waals forces are the primary drivers of interactions between PA and TPGS. In the ex vivo nasal mucosa permeation assay, the cumulative drug release at 24 h was 87.14% ± 5.34%,which was significantly higher than that of free PA. PA-NCs exhibited substantially improved cellular uptake as well as permeability on Calu-3 cells as compared to PA alone. FRET imaging analysis demonstrated that intact NCs could be internalized into Calu-3 cells.Moreover, PA-NCs conferred desirable protective effect against MPP+-induced SH-SY5Y cellular damage. Pharmacokinetic studies revealed a higher PA concentration in the brain following intranasal delivery of PA-NCs. In summary, the intranasal administration of PANCs is a promising treatment strategy for PD.

Nobiletin downregulates the SKP2-p21/p27-CDK2 axis to inhibit tumor progression and shows synergistic effects with palbociclib on renal cell carcinoma

Objective:Natural extracts,including nobiletin,have been reported to enhance the efficacy and sensitivity of chemotherapeutic drugs.However,whether and how nobiletin affects tumor growth and progression in renal cell carcinoma(RCC)are still unclear.Methods:Cell proliferation,cell cycle and apoptosis analyses,colony-formation assays,immunoblotting analysis,and q RT-PCR analysis were performed to investigate how nobiletin affected RCC cell proliferation in vitro.The nude mouse model was used to test the efficacy of nobiletin alone or in combination with palbociclib.Results:Nobiletin inhibited cell proliferation by inducing G1 cell cycle arrest and cell apoptosis in RCC cells.Mechanistically,nobiletin decreased SKP2 protein expression by reducing its transcriptional level.The downregulated SKP2 caused accumulation of its substrates,p27 and p21,which further inhibited the activity of the G1 phase-related protein,CDK2,leading to inhibition of cell proliferation and tumor formation.A higher SKP2 protein level indicated less sensitivity to the CDK4/6 inhibitor,palbociclib.A combination of nobiletin and palbociclib showed a synergistic tumor inhibition in vitro and in an in vivo model.Conclusions:Nobiletin downregulated the SKP2-p21/p27-CDK2 axis to inhibit tumor progression and showed synergistic tumor inhibition effects with the CDK4/6 inhibitor,palbociclib,on RCC,which indicates a potential new therapeutic strategy.

Deep eutectic solvent strategy enables an octahedral Ni–Co precursor for creating high-performance NiCo_(2)O_(4) catalyst toward oxygen evolution reaction

Deep eutectic solvents(DESs)have gained much attention in the fabrication of advanced nanoelectrocatalysts due to their amazing template function.However,their stabilizing function for easily hydrolyzed inorganic nanomaterials is rarely studied.Here,a DES-mediated strategy was reported to synthesize octahedral Ni–Co precursor(NiCo–NH_(3) complex),which could be directly transformed into NiCo_(2)O_(4) nanooctahedrons after thermal decomposition.The NiCo–NH_(3) precursor in octahedral shape was achieved with the DES-mediated crystallization in the choline chloride(ChCl)/glycerol.The ChCl/glycerol DES not only tailored the morphology of the as-prepared precursor by template effect but also inhibited its hydrolysis,ensuring the successful fabrication of octahedral NiCo–NH_(3) complex precursor with high yield.The NiCo–NH_(3) complex precursor was converted to well-defined NiCo_(2)O_(4) nanooctahedrons,where the calcination temperature and time were explored in detail.It revealed that DES could participate in the conversion process to control the morphology of calcination product.The resultant NiCo_(2)O_(4) nanooctahedrons demonstrated excellent electroactivity and remarkable durability for oxygen evolution reaction(OER).The present strategy not only offers an efficient OER electrocatalyst but also enriches the approaches of DESs in designing advanced nanocatalysts.

LoS MIMO Transmission for LEO Satellite Communication Systems

To provide global service with low latency, the broadband low earth orbits (LEO) satellite constellation based communication systems have become one of the focuses in academic and industry. To allow for wideband access for user links, the feeder link of LEO satellite is correspondingly required to support high throughput data communications. To this end, we propose to apply line-of-sight (LoS) multiple-input multiple-output (MIMO) transmission for the feeder link to achieve spatial multiplexing by optimizing the antenna arrangement. Unlike the LoS MIMO applications for static scenarios, the movement of LEO satellites make it impractical to adjust the optimal antenna separation for all possible satellite positions. To address this issue, we propose to design the antenna placement to maximize the ergodic channel capacity during the visible region of the ground station. We first derive the closed-form probability distribution of the satellite trajectory in visible region. Based on which the ergodic channel capacity can be then calculated numerically. The antenna placement can be further optimized to maximize the ergodic channel capacity. Numerical results verify the derived probability distribution of the satellite trajectory, and show that the proposed LoS MIMO scheme can significantly increase the ergodic channel capacity compared with the existing SISO one.

Optimization of Extraction Process of Yingshan Cloud Tea Polysaccharides by Response Surface Methodology

[Objectives] This study was conducted to explore the optimal process conditions for hot water extraction of polysaccharides from Yingshan cloud tea. [Methods] Based on single factor experiments, with the extraction rate of polysaccharides as the response value and liquid-to-solid ratio, extraction temperature and extraction time as investigation factors, the optimum extraction process for tea polysaccharides from Yingshan cloud tea was determined by Box-Behnken central componse design and response surface analysis method. [Results] Under the conditions of the liquid-to-solid ratio of 50∶1(ml/g), the extraction temperature at 94 ℃ and the extraction time of 210 min, the extraction rate of polysaccharides from Yingshan cloud tea reached 2.16%. [Conclusions] This study will provide theoretical basis and reference for subsequent related research.