基于微带谐振器的三维约束微波微等离子体源的实现

通过理论计算及HFSS仿真设计了微带谐振器,并通过比对三维约束结构存在的HFSS仿真结构验证了三维结构的可行性。实测制备的微带谐振器空载谐振频率为2.5GHz,回波损耗系数(S₁₁)为-17.94dB。该微带谐振器成功实现了三维约束微尺度下,工作频率为2.5GHz,工作压强范围为30Pa至大气压、功率范围为0.7~6W时的微等离子体放电。通过光谱仪检测压强为7.5×10⁴Pa下的H_β谱线,应用斯塔克展宽求得此压强下平均电子密度为5.54×10¹³cm^-3,该值符合微等离子体源的电子密度值。     

姜黄素磷脂复合物在大鼠体内的药代动力学评价

目的 通过对大鼠口服灌胃给药,评价姜黄素磷脂复合物在SD大鼠体内的药物代谢动力学性质。 方法 制备姜黄素磷脂复合物,以姜黄素作为对照,检测两者在水中的溶解度和体外累计溶出率;取SD大鼠12只,经口服灌胃给予姜黄素磷脂复合物或姜黄素混悬液后,不同时间点于大鼠眼底静脉丛取血,采用高效液相色谱法（HPLC）测定血浆中姜黄素的浓度。 结果 姜黄素磷脂复合物的溶解度、累计溶出率分别为0.150 g/L、68.04%,较姜黄素（0.057 g/L、50.68%）均有所增加。姜黄素磷脂复合物和姜黄素的药代动力学参数分别如下：C_max为（74.34±5.57） μg/L和（61.64±4.29） μg/L,T_max为（0.17±0） h和（0.25±0） h,AUC_0-t为（637.38±30.04） μg·h·L^-1和（172.41±31.66） μg·h·L^-1,AUC_0-∞为（857.80±223.69） μg·h·L^-1和（191.08±43.27） μg·h·L^-1。日内及日间精密度、回收率符合测定要求。 结论 姜黄素磷脂复合物混悬液与姜黄素相比吸收速度快,消除速率慢。     

血管紧张素Ⅱ1型受体自身抗体在甲亢大鼠心肌肥大中的作用及其与PI3K/Akt信号通路的关系

目的 观察甲亢心肌肥大大鼠血清血管紧张素Ⅱ1型受体自身抗体（AT₁-AA）与心肌组织磷脂酰肌醇-3-激酶（PI3K）、蛋白激酶B（Akt）的表达,探讨AT₁-AA在甲亢大鼠心肌肥大中的作用及其与PI3K/Akt信号通路的关系。方法 将54只SD大鼠随机分为3组：甲亢组、甲亢+奥美沙坦组及对照组,每组18只,前2组灌服左甲状腺素钠制备甲亢大鼠模型,甲亢+奥美沙坦组同时给予奥美沙坦。以心脏质量指数（HWI）和心钠肽（ANP）mRNA作为心肌肥大指标,采用酶联免疫吸附法（ELISA）检测大鼠血清AT₁-AA,并通过蛋白质印迹法检测各组大鼠血管紧张素Ⅱ1型受体（AT₁R）和PI3K/p-Akt的表达水平;根据AT₁-AA检测结果,将甲亢组和甲亢+奥美沙坦组大鼠分为AT₁-AA阳性组和阴性组,比较AT₁-AA阳性组和阴性组AT₁R及PI3K/p-Akt的表达情况。结果 （1）与对照组比较,甲亢组、甲亢+奥美沙坦组大鼠HWI增加,ANP mRNA相对表达量升高（P均<0.05）;甲亢组大鼠HWI及ANP mRNA相对表达量亦高于甲亢+奥美沙坦组大鼠（P<0.05）。（2）甲亢组、甲亢+奥美沙坦组大鼠AT₁-AA 阳性率及光密度（D）值（61.11%,72.22%和0.44±0.12,0.49±0.08）高于对照组（16.67%和0.28±0.05,P均<0.01）。（3）甲亢组、甲亢+奥美沙坦组大鼠AT₁R和PI3K/p-Akt的表达较对照组升高（P<0.05,P<0.01）;与甲亢组相比,甲亢+奥美沙坦组大鼠心肌组织PI3K、p-Akt表达水平均降低（P<0.01,P<0.05）。（4）甲亢组大鼠中,AT₁-AA阳性组PI3K/p-Akt的表达明显高于AT₁-AA阴性组（P<0.01）;甲亢+奥美沙坦组大鼠中,AT₁-AA阳性组PI3K/p-Akt的表达较AT₁-AA阴性组降低（P<0.05）。结论 AT₁-AA可能通过AT₁R激活PI3K/Akt信号通路参与甲亢心肌肥大病理生理过程。     

Li2SiO3:Eu3+红色荧光粉的制备与发光性能

以LiOH·H₂O、Si（OC₂H₅）₄和Eu（NO₃）₃·6 H₂O为主要原料,采用简单的机械球磨法,在室温下合成了Li₂SiO₃：Eu³⁺荧光粉前驱体,再经高温灼烧,得到一系列Li₂SiO₃：x% Eu³⁺红色荧光粉。研究了灼烧温度、保温时间及Eu³⁺的物质的量浓度对产物的结构和发光性能的影响。结果表明,当x在1.5~15这个较宽的范围内,随着Eu³⁺物质的量的增加,Li₂SiO₃：x% Eu³⁺荧光粉的物相组成保持不变,且直到x值达到12之后,才出现了浓度淬灭现象;当灼烧温度为1 173 K、保温时间为2 h时,荧光材料的发光强度达到最大值。在467 nm激发下,基于Eu³⁺的⁵D₀→⁷F₂（615 nm）跃迁,Li₂SiO₃：Eu³⁺荧光粉发射出强烈的红光。     

氢分子对H2O2体外诱导氧化损伤大鼠脊髓神经元的保护作用简

目的 证明氢分子对过氧化氢（H₂O₂）诱导氧化损伤的大鼠脊髓神经元具有保护效应,并初步探讨其相关机制。方法 将纯化培养7 d后的大鼠脊髓神经元分为4组：（1）常规培养液（NM）对照组：以NM培养;（2）富氢培养液（HM）组：以HM培养;（3）NM+H₂O₂组：以NM培养2 h后,加入100 μmol/L H₂O₂和15 μmol/L FeCl₂继续培养;（4）HM+H₂O₂组：以HM培养2 h后,加入100 μmol/L H₂O₂和15 μmol/L FeCl₂继续培养。各组处理后每6 h更换各自培养液及氧化剂,在12 h后停止处理并检测神经元胞内活性氧（ROS）生成的水平、细胞凋亡情况,以及糖元合成激酶3β（GSK-3β）和p-GSK-3β的表达水平。结果 与NM相比,HM可降低H₂O₂氧化损伤后神经元胞内ROS尤其是羟自由基（HO·）的生成（P<0.01）,减少神经元凋亡的数量（P<0.01）,下调caspase-3的表达（P<0.01）,促进GSK-3β的磷酸化（P<0.01）。结论 氢分子对H₂O₂氧化损伤的神经元具有保护效应,其机制与降低神经元胞内ROS尤其是HO·的生成、减少神经元凋亡的数量和抑制凋亡信号通路的激活以及促进GSK-3β的磷酸化利于神经元生长有关。     

单向灌流法研究阿奇霉素泡囊的大鼠在体肠吸收

目的 研究阿奇霉素泡囊的大鼠在体肠吸收性质。方法 选择健康SD雄性大鼠6只,分为2组,运用单向灌流模型考察大鼠的十二指肠、空肠、回肠以及结肠在灌流速度为0.2 mL/min以及灌流时间为1 h条件下的药物吸收情况。采用HPLC法对药物的质量浓度进行检测,并计算其吸收速率常数（K_a）及有效渗透率（P_eff）。结果 阿奇霉素泡囊在十二指肠、空肠、回肠以及结肠的K_a和P_eff分别是阿奇霉素的2.41、2.35、2.54、2.95倍和2.34、1.47、2.20、1.40倍,差异均有统计学意义（P<0.05）。结论 阿奇霉素泡囊能明显改善药物在体肠吸收。     

去肾交感神经术对大鼠急性心肌梗死后心室重构的影响

目的 对急性心肌梗死（myocardial infarction,MI）大鼠进行双侧肾交感神经切除,探讨去肾交感神经术（renal sympathetic denervation,RDN）能否缓解MI后心室重构并进行可能的机制探讨。方法 结扎大鼠左冠状动脉前降支构建MI模型,实验分组为：MI组（n=10）、MI+RDN组（MI建模1周后进行RDN,n=10）和假手术组（n=10）。MI建模4周后对各组大鼠进行超声心动图检查测定心室重构程度和左心功能,对梗死边缘区心肌进行Masson染色观察心肌纤维化程度,免疫组化检测Ⅰ型胶原、Ⅲ型胶原和转化生长因子 β₁（transforming growth factor β₁,TGF-β₁）的表达。结果 与MI组相比,MI+RDN组的左室射血分数（ejection fraction,EF）和短轴缩短率（fractional shortening,FS）升高,左室收缩末期内径（left ventricular internal dimensions at end systole,LLüIDS）和左室舒张末期内径（left ventricular internal dimensions at end diastole,LLüIDD）减少（P均<0.05）。心肌Masson染色结果显示,MI+RDN组大鼠梗死边缘区的心肌纤维化程度较MI组减轻。免疫组化检测显示,与MI组相比,MI+RDN组大鼠梗死边缘区的Ⅰ型胶原、Ⅲ型胶原和TGF-β₁表达减少（P均<0.05）。结论 RDN可以改善MI大鼠心室重构,提高左心收缩功能,其机制可能与局部下调心肌TGF-β₁表达进而减少Ⅰ型胶原和Ⅲ型胶原沉积有关。     

基于多级质谱裂解规律结合SD大鼠在体肠襻给药模型研究西地那非经肠吸收与代谢特性

目的 探讨西地那非及其活性代谢产物N-去甲西地那非的液相色谱-电喷雾多级质谱[LC-ESI（+）MSⁿ]裂解规律,考察西地那非经肠吸收与代谢特征。 方法 采用ESI质谱分析技术,在正离子检测模式下,分别对西地那非、N-去甲西地那非进行LC-ESI（ ）MSⁿ裂解分析,解析其中的主要碎片离子以及可能的裂解途径。基于裂解规律建立西地那非、N-去甲西地那非的LC-ESI（ ）MS/MS的SD大鼠血浆样品分析方法,取25只成年健康雄性SD大鼠,随机分成5组,每组5只,以在体肠襻给药模型法给予硫酸氢钠西地那非原料药10 mg/kg,于给药前及给药后0.25、0.5、1、4 h时在肝门静脉处取血测定,每个时间点一组SD大鼠,考察药物经肠道吸收及在肠系膜处代谢情况。 结果 质谱裂解规律表明,西地那非及N-去甲西地那非均获得丰度较高的m/z 311、283特征碎片质谱峰,证明药物在C-S键处不稳定易发生断裂脱去C₅H₁₂O₂N₂S,在乙氧基C-O键处不稳定易发生断裂脱去C₂H₄,最终形成稳定m/z 283碎片离子。以m/z 475→m/z 283（西地那非）和m/z 461→m/z 283（N-去甲西地那非）为离子反应监测通道对在体肠襻给药模型进行半定量分析,结果表明除以原型药物西地那非的形式吸收外,在体肠中约有1/5原型药物经肠代谢生成活性代谢产物N-去甲西地那非,并与原型药物同时吸收。 结论 西地那非和N-去甲西地那非经质谱裂解均形成稳定的m/z 283二级碎片离子;西地那非在体肠吸收时伴随氮去甲基代谢反应同时发生,约有1/5的原型药物代谢生成活性代谢产物N-去甲西地那非。     

硫酸亚铁水合物在稀硫酸中溶解度的测定及其晶体存在形式

采用静态平衡法测定了温度为293.15~363.15 K时硫酸亚铁水合物在质量分数为1%和3%硫酸中的溶解度数据。同时利用X射线衍射和热重分析相结合的方法对晶体组成进行分析,确定其不同的存在形式。结果表明:在w=1%硫酸中,硫酸亚铁水合物以FeSO₄·7H₂O、FeSO₄·4H₂O和FeSO₄·H₂O三种形式存在;在w=3%硫酸中,硫酸亚铁水合物以FeSO₄·7H₂O和FeSO₄·H₂O两种形式存在。硫酸亚铁水合物的溶解度受温度、硫酸质量分数影响较大,以硫酸亚铁为基准,随着温度升高溶解度先增加,当温度大于转变温度后,溶解度随温度升高而减小。同一温度下,硫酸质量分数越高,溶解度越小。硫酸亚铁水合物在稀硫酸中晶体存在形式及溶解度数据为硫酸亚铁湿法转晶研究提供了重要的热力学基础数据。     

高脂诱导五指山小型猪动脉粥样硬化模型的建立及Lp-PLA2的表达调控

目的 高脂诱导建立五指山小型猪动脉粥样硬化（AS）模型,观察脂蛋白相关磷脂酶A₂（Lp-PLA₂）在AS模型血浆和斑块中的表达变化。方法 将10只五指山小型猪随机分为正常对照（Ctr）组4只饲喂普通饲料、AS模型（AS model）组6只饲喂高脂饲料,连续造模24周。造模24周时,空腹取前腔静脉血测定总胆固醇（TC）、低密度脂蛋白（LDL-C）、高密度脂蛋白（HDL-C）、甘油三酯（TG）、C-反应蛋白（CRP）、Lp-PLA₂活性和成分的变化,并取主动脉进行油红O染色以及取腹主动脉血管行HE染色和IL-6免疫组化染色,观察血管脂质沉积和斑块病理以及IL-6蛋白表达变化。采用RT-PCR和Western Blot法观察腹主动脉组织中Lp-PLA₂mRNA和蛋白的表达情况。结果 与正常对照组比,AS模型组体重、体质量指数（BMI）、TC、LDL-C、HDL-C、CRP、Lp-PLA₂活性和成分均显著升高（P < 0.05,P < 0.01）,同时主动脉脂质沉积明显（P < 0.01）和AS斑块形成,腹主动脉组织中Lp-PLA₂mRNA和蛋白表达以及IL-6蛋白表达均显著升高（P < 0.05）。结论 长期高脂饮食24周能诱发五指山小型猪AS,且Lp-PLA₂在参与血管炎症和AS斑块形成中发挥了关键作用。     

HT-7装置中低杂波电流驱动时的电子温度

在HT-7托卡马克实验装置中采用低杂波电流驱动,在不同低杂波功率和电子密度(ne)下,考察中心电子温度和能量约束时间的变化。观察到当ne=1.3×1019～2.6×1019 m-3时,中心电子温度随低杂波输入功率的增大而升高;当ne=1.3×1019 m-3,低杂波输入功率为400 kW时,电子温度最高,达到1.37 keV。在本实验参数范围内,其能量约束时间与ITER89P L模定标率十分吻合。比较欧姆加热和低杂波加热下的电子温度分布,当ne=1.71×1019 m-3,低杂波输入功率为260 kW时,电子温度有明显的温度梯度出现。     

GC-NICI-MS analysis of acetazolamide and other sulfonamide (R-SO2-NH2)drugs as pentafluorobenzyl derivatives [R-SO2-N(PFB)2] and quantification of pharmacological acetazolamide in human urine

Acetazolamide(molecular mass(MM),222)belongs to the class of sulfonamides(R-SO2-NH2)and is one of the strongest pharmacological inhibitors of carbonic anhydrase activity.Acetazolamide is excreted unchanged in the urine.Here,we report on the development,validation and biomedical application of a stable-isotope dilution GC-MS method for the reliable quantitative determination of acetazolamide in human urine.The method is based on evaporation to dryness of 50 mL urine aliquots,base-catalyzed derivatization of acetazolamide(d0-AZM)and its internal standard[acetylo-2H3]acetazolamide(d3-AZM)in 30 vol%pentafluorobenzyl(PFB)bromide in acetonitrile(60 min,30
C),reconstitution in toluene(200 mL)and injection of 1-mL aliquots.The negative-ion chemical ionization(NICI)mass spectra(methane)of the PFB derivatives contained several intense ions including[M]‒at m/z 581 for d0-AZM and m/z 584 for d3-AZM,suggesting derivatization of their sulfonamide groups to form N,N-dipentafluorobenzyl derivatives(R-SO2-N(PFB)2),i.e.,d0-AZM-(PFB)2 and d3-AZM-(PFB)2,respectively.Quantification was performed by selected-ion monitoring of m/z 581 and 83 for d0-AZM-(PFB)2 and m/z 584 and 86 for d3-AZM-(PFB)2.The limits of detection and quantitation of the method were determined to be 300 fmol(67 pg)and 1 mM of acetazolamide,respectively.Intra-and inter-assay precision and accuracy for acetazolamide in human urine samples in pharmacologically relevant concentration ranges were determined to be 0.3%e4.2%and 95.3%e109%,respectively.The method was applied to measure urinary acetazolamide excretion after ingestion of a 250 mg acetazolamide-containing tablet(Acemit®)by a healthy volunteer.Among other tested sulfonamide drugs,methazolamide(MM,236)was also found to form a N,N-dipentafluorobenzyl derivative,whereas dorzolamide(MM,324)was hardly detectable.No GC-MS peaks were obtained from the PFB bromide derivatization of hydrochlorothiazide(MM,298),xipamide(MM,355),indapamide and metholazone(MM,366 each)or brinzolamide(MM,384).We demonstrate for the first time that sulfonamide drugs can be derivatized with PFB bromide and quantitated by GC-MS.Sulfonamides with MM larger than 236 are likely to be derivatized by PFB bromide but to lack thermal stability.     

Nitrogen-doped carbon@TiO2 double-shelled hollow spheres as an electrochemical sensor for simultaneous determination of dopamine and paracetamol in human serum and saliva

As the most commonly used antipyretic and analgesic drug, paracetamol (PA) coexists with neurotransmitter dopamine (DA) in real biological samples. Their simultaneous determination is extremely important for human health, but they also interfere with each other. In order to improve the conductivity, adsorption affinity, sensitivity, and selectivity of TiO₂-based electrochemical sensor, N-doped carbon@TiO₂ double-shelled hollow sphere (H–C/N@TiO₂) is designed and synthesized by simple alcoholic and hydrothermal method, using polystyrene sphere (PS) as a template. Meanwhile, TiO₂ hollow spheres (H–TiO₂) or N-doped carbon hollow spheres (H–C/N) are also prepared by the same method. H–C/N@TiO₂ has good conductivity, charge separation, and the highly enhanced and stable current responses for the detection of PA and DA. The detection limit and linear range are 50.0 nmol/L and 0.3–50 μmol/L for PA, 40.0 nmol/L and 0.3–50 μmol/L for DA, respectively, which are better than those of carbon-based sensors. Moreover, this electrochemical sensor, with high selectivity, strong anti-interference, high reliability, and long time durability, can be used for the simultaneous detection of PA and DA in human blood serum and saliva. The high electrochemical performance of H–C/N@TiO₂ is attributed to the multi-functional combination of different layers, because of good conductivity, absorption and electrons transfer ability from in-situ N-doped carbon and electrocatalytic activity from TiO₂.     

不对称树状聚两性电解质的合成及pH响应性自组装行为

通过发散法、开环聚合以及“点击化学”等方法合成了树状聚两性电解质聚（L-赖氨酸）-聚酰胺-胺-聚（L-谷氨酸）[（PLL）₄-D2-b-D1-（PLGA）₂],其中,D1和D2分别代表第1代和第2代聚酰胺-胺。通过氢核磁共振波谱（¹H-NMR）、傅里叶变换红外光谱（FT-IR）和凝胶渗透色谱（GPC）对产物的分子结构、相对分子质量及其分布进行了表征;结合电位电导滴定、¹H-NMR、Zeta电位测定、扫描电子显微镜（SEM）、透射电子显微镜（TEM）和动态光散射（DLS）等表征方法研究了（PLL）₄-D2-b-D1-（PLGA）₂溶液的pH响应性自组装行为。研究结果表明,（PLL）₄-D2-b-D1-（PLGA）₂具有pH响应性多重胶束化行为,在酸性条件下形成PLL为壳、PLGA为核的聚集体,而在碱性条件下形成PLGA为壳、PLL为核的聚集体,同时伴随着PLGA和PLL链段从无规线团到α-螺旋构象的转变。随着溶液pH的增加,自组装聚集体由球形胶束向棒状胶束再向纺锤形胶束转变,并在高pH下二次自组装形成松叶状分形结构。     

An Appreciation for the Rabbit Ladderlike Modeling of Radiation-induced Lung Injury with High-energy X-Ray

Background:

To evaluate the utility of rabbit ladderlike model of radiation-induced lung injury (RILI) for the future investigation of computed tomography perfusion.

Methods:

A total of 72 New Zealand rabbits were randomly divided into two groups: 36 rabbits in the test group were administered 25 Gy of single fractionated radiation to the whole lung of unilateral lung; 36 rabbits in the control group were sham-radiated. All rabbits were subsequently sacrificed at 1, 6, 12, 24, 48, 72 h, and 1, 2, 4, 8,1 6, 24 weeks after radiation, and then six specimens were extracted from the upper, middle and lower fields of the bilateral lungs. The pathological changes in these specimens were observed with light and electron microscopy; the expression of tumor necrosis factor-α (TNF-a) and transforming growth factor-β1 (TGF-β₁) in local lung tissue was detected by immunohistochemistry.

Results:

(1) Radiation-induced lung injury occurred in all rabbits in the test group. (2) Expression of TNF-a and TGF-β₁ at 1 h and 48 h after radiation, demonstrated a statistically significant difference between the test and control groups (each P < 0.05). (3) Evaluation by light microscopy demonstrated statistically significant differences between the two groups in the following parameters (each P < 0.05): thickness of alveolar wall, density of pulmonary interstitium area (1 h after radiation), number of fibroblasts and fibrocytes in interstitium (24 h after radiation). The test group metrics also correlated well with the time of postradiation. (4) Evaluation by electron microscopy demonstrated statistically significant differences in the relative amounts of collagen fibers at various time points postradiation in the test group (P < 0.005), with no significant differences in the control group (P > 0.05). At greater than 48 h postradiation the relative amount of collagen fibers in the test groups significantly differ from the control groups (each P < 0.05), correlating well with the time postradiation (r = 0.99318).

Conclusions:

A consistent and reliable rabbit model of RILI can be generated in gradient using 25 Gy of high-energy X-ray, which can simulate the development and evolution of RILI.     

丁苯橡胶为黏合剂的聚丙烯硫酸钡复合膜的制备

以丁苯橡胶（SBR）为黏合剂、羧甲基纤维素钠（CMC）为分散剂、聚丙烯（PP）膜为基体,在其两侧涂覆厚度2 μm的硫酸钡（BaSO₄）颗粒,得到一种复合电池隔膜。对复合膜的形貌、润湿性、热稳定性、电导率等进行了研究。结果表明：BaSO₄涂层均匀涂布于PP膜表面,使复合膜中小于200 nm的孔增多。同PP膜相比,复合膜具有较小的热收缩率和较好的润湿性。而与聚偏氟乙烯（PVDF）黏合剂相比,SBR具有更强的黏合性。以复合膜做为隔膜的电池在不同电流密度下具有更高的容量保持率。     

电针对慢性挤压伤大鼠坐骨神经病理形态学和背根神经节P2X3受体敏感性的影响

Objective: To explore the effect of electroacupuncture (EA) on the pathomorphology of the sciatic nerve and the role of P2X3 receptors in EA analgesia. Methods: The chronic constriction injury (CCI) model was adopted in this study. A total of 32 rats were randomly divided into four groups: sham CCI, CCI, CCI plus contralateral EA (CCI + conEA) and CCI plus ipsilateral EA (CCI + ipsEA). Mechanical withdrawal threshold (MWT) and thermal withdrawal latency (TWL) were measured. EA began at day 7 after the CCI operation and was applied to the Zusanli (ST 36) and Yanglingquan acupoints (GB 34). At day 14, the pathomorphologic changes of the operated sciatic nerve were demonstrated by hematoxylin and eosin staining. In addition, dorsal root ganglion (DRG) neurons isolated from rats were examined by electrophysiological recording to determine if the P2X3 receptor agonists, adenosine 5''-triphosphate disodium (ATP) and α,β-methylen-ATP (α,β-meATP) evoked inward currents. Results: Pain thresholds in the CCI group were obviously decreased post CCI surgery (P<0.01). In the EA groups, thermal and mechanical threshold values were increased after the last EA treatment (P<0.05, P<0.01). There was no significant difference in light microscopic examination among the four groups (P>0.05). Current amplitude after application of ATP and α,β-meATP in DRG neurons were much larger in the CCI group compared to those obtained in sham CCI (P<0.05). ATP and α, β-meATP invoked amplitudes in the CCI + EA groups were reduced. There was no significant difference between the CCI + conEA group and the CCI + ipsEA group (P>0.05). Conclusion : EA analgesia may be mediated by decreasing the response of P2X3 receptors to the agonists ATP and α,β-meATP in the DRG of rats with CCI. No pathological changes of the sciatic nerve of rats were observed after EA treatment.     

Highly sensitive electrochemical determination of rutin based on the synergistic effect of 3D porous carbon and cobalt tungstate nanosheets

Rutin, a flavonoid found in fruits and vegetables, is a potential anticancer compound with strong anticancer activity. Therefore, electrochemical sensor was developed for the detection of rutin. In this study, CoWO₄ nanosheets were synthesized via a hydrothermal method, and porous carbon (PC) was prepared via high-temperature pyrolysis. Successful preparation of the materials was confirmed, and characterization was performed by transmission electron microscopy, scanning electron microscopy, and X-ray photoelectron spectroscopy. A mixture of PC and CoWO₄ nanosheets was used as an electrode modifier to fabricate the electrochemical sensor for the electrochemical determination of rutin. The 3D CoWO₄ nanosheets exhibited high electrocatalytic activity and good stability. PC has a high surface-to-volume ratio and superior conductivity. Moreover, the hydrophobicity of PC allows large amounts of rutin to be adsorbed, thereby increasing the concentration of rutin at the electrode surface. Owing to the synergistic effect of the 3D CoWO₄ nanosheets and PC, the developed electrochemical sensor was employed to quantitively determine rutin with high stability and sensitivity. The sensor showed a good linear range (5–5000 ng/mL) with a detection limit of 0.45 ng/mL. The developed sensor was successfully applied to the determination of rutin in crushed tablets and human serum samples.     

A transmission electron microscopy study of the diversity of Candida albicans cells induced by Euphorbia hirta L. leaf extract in vitro

Objective

To determine the major changes in the microstructure of Candida albicans (C. albicans) after treatment with Euphorbia hirta (E. hirta) L. leaf extract.

Methods

Transmission electron microscopy was used to study the ultrastructural changes caused by E. hirta extract on C. albicans cells at various exposure time.

Results

It was found that the main abnormalities were the alterations in morphology, lysis and complete collapse of the yeast cells after 36 h of exposure to the extract. Whereas the control cultures showed a typical morphology of Candida with a uniform central density, typically structured nucleus, and a cytoplasm with several elements of endomembrane system and enveloped by a regular, intact cell wall.

Conclusions

The significant antifungal activity shown by this methanol extract of E. hirta L. suggests its potential against infections caused by C. albicans. The extract may be developed as an anticandidal agent.     

Stability-indicating liquid chromatographic method for the determination of Letrozole in pharmaceutical formulations

A stability-indicating high-performance liquid chromatographic method was developed and validated for the determination of Letrozole in tablet dosage forms. Reversed-phase chromatography was performed on Shimadzu Model LC-Class-Vp with Lichrocart/Lichrosphere 100 C-18 (250 mm×4.6 mm, 5 μm particle size) column with methanol: tetra butyl ammonium hydrogen sulfate (80:20V/V) as mobile phase at a flow rate of 1 mL/min with UV detection at 240 nm. Linearity was observed in the concentration range of 0.5–150 μg/mL (R²=0.9998) with regression equation y=102582x+43185. The limit of quantitation (LOQ) and limit of detection (LOD) were found to be 0.043 and 0.012 μg/mL respectively. The forced degradation studies were performed by using HCl, NaOH, H₂O₂, thermal and UV radiation. Letrozole is more sensitive towards alkaline conditions and very much resistant towards acidic, oxidative and photolytic degradations. The method was validated as per ICH guidelines. The RSD for intra-day (0.78–0.97) and inter-day (0.86–0.96) precision were found to be lesser than 1%. The percentage recovery was in good agreement with the labeled amount in the pharmaceutical formulations and the method is simple, specific, precise and accurate for the determination of Letrozole in pharmaceutical formulations.