Synthesis of two new thiazolidines and their hepatoprotective effects

Two new 2-substituted thiazolidine-4（R）-carboxylic acids （TCAs）, 2-glusosaminal-TCA （GIcNH2Cys） and 2-N-acetyl-glueosanlinal-TCA （GlcNAeCys）, were synthesized. Their protective effects against liver toxicity induced by acetaminophen （APAP） were investigated in a mice model. The resuits demonstrate that administration of TCAs （ i. p. , 800 mg/kg） 30 min after APAP challenge efficiently decrease ALF, AST, and LDH levels in liver. GlcNAcCys shows the best proteetive eftects, decreasing ALT, AST and LDH levels to 63%, 18.4% and 37% of the APAP group respectively. Comparison with the control showed that APAP greatly decreases total sulfhydlyl （T-SH） levels （43%）, non-protein hound sulfhydryl （NP-SH） levels （50%） and total antioxidative capabilities （57%） in the liver 24 hr after challenge. TCAs treatments 30min after APAP challenge significantly elevate sulfhydryl levels and total antioxidative capabilities. APAP administration also markedly （P 〈 0.05） increases liver lipid peroxidation to 1.65 and 1.17 times that of the control 4 hr and 24 hr after APAP administration respectively. TCAs treatments can inhibit lipid peroxidation as measured by decreased malondialdehyde （MDA） contents in liver. The histopathological results also further confirm the hepatoprotective effects of TCAs. In conclusion, our data show that TCAs, GleNAcCys particularly, have hepatoprotective anti antioxidant etfects.     

猕猴结肠镜检查前的肠道准备

摘要:猕猴是非常重要且珍贵的实验动物。 不处死猕猴为前提,以反复多次对猕猴进行全结肠肠道检查及研究为。目的,建立猕猴全结肠内镜检查前的肠道准备方法尤为重要。 本研究补充此方法目前尚无报道的空白。 30 只猕猴,结肠镜检查前 3 h 分多次予以芒硝溶液管喂。 通过肠镜观察肠道清洁情况,其中 3 只猕猴肠道准备为Ⅲ 级,其余猕猴肠道准备均为Ⅰ ~ Ⅱ 级。 所有猕猴在洗肠过程中,无严重脱水、休克、死亡等并发症发生,肠道准备为Ⅰ ~ Ⅱ级猕猴顺利完成全结肠内镜检查。     

区域碳减排份额分配的综合指数构建

科学实用地分配各区域的碳减排责任是实现全国减排目标的关键,而准确合理地核算碳排放基数是分配各区域减排责任的基础,综合系统的衡量指标和方法是分配各区域减排责任的核心.除了直接能源消费产生的"显性碳排放",省际贸易往来造成的"隐含碳"转移也是不容忽视的一部分.因此,从公平和效率原则出发,考虑省际贸易的影响,运用多准则决策方法,建立区域碳减排份额初始分配的熵权TOPSIS模型,实证分析结果贴合实际,基本准确.     

Bundling strategies for platforms with an installed base

As an emerging platform, hardware/software platforms differ from traditional retail platforms because they require consumers to spend a certain amount of money accessing them. Therefore, an installation base is created. Considering the game console as an example, only consumers with an installation base can purchase a third-party game product on the platform. Otherwise, consumers will be unable to play games. It is generally believed that the existence of an installed base will benefit third-party content providers, and at the same time, it will not benefit platform manufacturers. Therefore, it can be observed that game platforms often bundle new consoles with third-party content, forcing consumers with installed bases to purchase a new console. Thus, building a model to study the impact of the installation based on the bundling strategy of the video game platform and to analyze the optimal pricing and profit under different bundling strategies is meaningful. Our study analyzed the impact of the installed base under different bundling strategies and found that the installed base dose not always have a positive impact on platform manufacturers. The study also analyzed the equilibrium of competing platform manufacturers and found that, under certain conditions, both the bundling-bundling strategy and the unbundling-unbundling strategy may exist as equilibrium.     

超大伸缩比机械臂结构设计及其刚度优化方法

定期清理灰库内壁板结干灰已成为保障火电厂机组安全运营的重要措施。针对现有灰库清理机器人普遍存在的清理区间局限、整机刚度不足等突出问题,通过引入基于绳排的同步伸缩驱动机构,融合轻量化高刚度的多节箱式臂体及柔性周向回转关节,创新设计出一款基于超大伸缩比机械臂的灰库全域面清理机器人。在此基础上,通过深入力学分析建立伸缩臂力学模型并提出刚度条件。利用迭代法对伸缩臂截面参数进行优化,获得不同情况下最优截面参数。仿真实验表明经刚度优化后的伸缩臂整体刚度良好,满足灰库清理机器人长期作业要求。     

CHARACTERISTIC THEOREMS OF TH ENATURAL TCHEBYSHEFF SPLINE FUNCTION

In this paper,we give four characteristic theorems of the natural Tchebysheff splint functionassociated with multiple knots.These theorems possess specific form,that arc convenient forapplicaton;In the case of with simple knots or polynomial splint,the corollaries of this paper's the-orems give corresponding results.     

R&D的会计视角分析:追溯资本化法优势分析及重塑

随着企业研究与开发(R&D)活动中持续升温,R&D的会计处理问题备受关注。本文对当前R&D的会计处理方法进行剖析后认为,对R&D,追溯资本化法要比全额费用化法和一定条件下的资本化法更加合理,而将传统的追溯资本化法进行必要修正,能够使追溯资本化法更加完善、科学,不失为一种对R&D会计处理的有益尝试。     

卫星通信下行链路鲁棒安全波束成形设计

针对多波束卫星通信系统下行链路存在多个窃听者的场景, 在仅已知窃听者大概位置的条件下, 提出了两种鲁棒安全波束成形(beamforming, BF)方案。一种是基于卫星总发射功率受限条件下的系统安全速率最大化准则, 提出了基于广义瑞利商的鲁棒BF方案, 得到了BF权矢量的解析解。另一种是基于安全速率和卫星总发射功率约束下的安全能效最大化准则, 提出了一种分式规划、罚函数以及凸差(difference of convex, DC)规划理论相结合的嵌套迭代算法, 完成鲁棒BF设计。仿真结果表明, 跟传统的非鲁棒BF方案相比, 所提出的两种鲁棒BF方案能够获得更好的安全性能。     

恒定磁场下的磁性液滴变形数值模拟

采用商业数值软件Fluent模拟研究磁液滴在恒定磁场中的运动变形情况.模拟考查磁液滴在空气中处于悬浮状态时,受到水平方向的恒磁场作用,进而发生运动变形行为.研究结果表明:磁通密度越大,对液滴造成的影响越大,液滴更加容易发生移动变形行为;另外,磁液滴尺寸越大,越容易受到磁场的影响发生变形;磁液滴发生变形存在最低磁通密度,即临界磁通密度,该参数随液滴直径的增加而减少;当液滴尺寸无限小,无论施加何种强度的磁通密度均无法实现液滴的变形;当液滴直径达到5.4 mm以上时,即便不存在磁场作用,在无外界能量维系的前提下,液滴本身也会发生变形,无法保持液滴球形的完整性.     

基于全寿命周期成本的配电网多阶段无功规划

以无功补偿方案全寿命周期净收益现值为目标函数,建立了多阶段配电网无功规划数学模型.不仅考虑了多阶段配电网无功规划方案的初始投资、运行维护成本、报废成本,反映了无功补偿方案全寿命周期的降损节能收益能力,还考虑了配电网在不同阶段的无功负荷需求,使无功补偿设备可以分阶段进行安装建设,优化了工程投资.提出了一种混沌多粒子群算法并对上述模型进行求解,该算法克服了基本粒子群算法早熟问题.最后,通过配电网无功规划实例验证了上述模型和方法的正确性及有效性.