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排序方式: 共有3047条查询结果,搜索用时 15 毫秒
1.
目的基于紫外(UV)和高效液相(HPLC)全息指纹图谱,化学模式识别技术与多成分定量相结合的方法,整合评价不同生长发育时期的49批夏枯草Prunella vulgaris样品化学成分的变化规律,从而阐明夏枯草由草到药的演变过程,解释夏枯草"夏枯质优"的科学内涵。方法建立不同生长发育时期49批夏枯草样品的UV和HPLC全息指纹图谱,采用主成分分析(principal component analysis,PCA)、偏最小二乘法-判别分析(partial leastsquares-discriminant analysis,PLS-DA)对其进行评价,筛选出影响夏枯草分类的特异性吸收波段,并对主要差异性化学成分进行含量测定。结果建立了不同生长发育时期49批夏枯草样品的UV和HPLC指纹图谱,PCA和PLS-DA分析可直观显示夏枯草样品中总的化学组分在不同生长发育时期时动态的变化趋势,其中夏枯草枯萎期可以明显的和其他4个时期区分开来,且其他4个时期有向枯萎期动态渐变的趋势。UV指纹图谱通过PLS-DA筛选出特异性吸收波段为261 nm,HPLC指纹图谱利用PLS-DA的变量因子(VIP)分布图,筛选出VIP值大于1.3的2个色谱峰,经指认为异迷迭香酸苷和迷迭香酸,确定为主要差异性化学成分。对不同生长发育时期的夏枯草差异性化学成分进行含量测定,其中迷迭香酸的含量为0.020%~0.344%;异迷迭香酸苷的含量为0.0016%~0.0988%。多成分定量结果说明,果穗枯萎期中异迷迭香酸苷和迷迭香酸的含量明显增加。含量测定结果与指纹图谱模式识别结果一致,两者可相互验证。结论指纹图谱结合化学模式识别技术与多成分定量,多种分析方法并用,全方位整合的技术手段,实现了对夏枯草从草到药的整个生长发育过程中整体化学信息的动态监测。该方法分析全面、操作简便,为阐明"夏枯质优",规范夏枯草药材采收及全面评价药材质量提供参考。 相似文献
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Current COVID-19 pandemic caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has put a spotlight on the spread of infectious diseases brought on by pathogenic airborne bacteria and viruses. In parallel with a relentless search for therapeutics and vaccines, considerable effort is being expended to develop ever more powerful technologies to restricting the spread of airborne microorganisms in indoor spaces through the minimization of health- and environment-related risks. In this context, UV-based and photocatalytic oxidation (PCO)-based technologies (i.e., the combined action of ultraviolet (UV) light and photocatalytic materials such as titanium dioxide (TiO2)) represent the most widely utilized approaches at present because they are cost-effective and ecofriendly. The virucidal and bactericidal effect relies on the synergy between the inherent ability of UV light to directly inactivate viral particles and bacteria through nucleic acid and protein damages, and the production of oxidative radicals generated through the irradiation of the TiO2 surface. In this literature survey, we draw attention to the most effective UV radiations and TiO2-based PCO technologies available and their underlying mechanisms of action on both bacteria and viral particles. Since the fine tuning of different parameters, namely the UV wavelength, the photocatalyst composition, and the UV dose (viz, the product of UV light intensity and the irradiation time), is required for the inactivation of microorganisms, we wrap up this review coming up with the most effective combination of them. Now more than ever, UV- and TiO2-based disinfection technologies may represent a valuable tool to mitigate the spread of airborne pathogens. 相似文献
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目的建立两色金鸡菊醇提物的质量标准。方法通过薄层色谱法(TLC)、水分测定、炽灼残渣测定、紫外分光光度法和高效液相色谱法对两色金鸡菊醇提物进行质量控制。结果薄层色谱显示供试品与对照品绿原酸斑点在相同的位置上显相同颜色,供试品鉴别分离出马里苷、黄酮奥卡宁和奥卡宁3个主要成分;两色金鸡菊醇提物的水分不得超过15%;炽灼残渣不得超过16%;两色金鸡菊醇提物中绿原酸含量(C_(16)H_(24)O_(12))不得少于0.8%;flavanomarein含量(C_(21)H_(22)O_(11))不得少于4%;marein含量(C_(21)H_(22)O_(11))不得少于8.5%;3,5-二咖啡酰基奎宁酸含量(C25H24O12)不得少于0.5%;总黄酮含量不得低于9%;总酚酸含量不得低于28.0%。结论根据《中国药典》中药质量标准研究制定技术要求建立了一套完整的两色金鸡菊醇提物质量标准。建立了TLC可定性鉴别两色金鸡菊醇提物中的各主要成分,通过一测多评法可定量控制两色金鸡菊醇提物中绿原酸、flavanomarein、marein和3,5-二咖啡酰基奎宁酸的含量,建立紫外分光光度法可测定两色金鸡菊醇提物中的总黄酮、总酚酸的含量。 相似文献
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《Actas dermo-sifiliográficas》2020,111(5):390-397
Background and objectiveThe minimal erythema dose (MED), an essential measurement in studies of skin photosensitivity, requires establishing MED values for specific populations, given genetic variation. Different ways to assess erythema are also relevant. We aimed to determine MED values in a sample of Colombian patients and correlations between MED and Fitzpatrick skin type. We also studied concordance correlation between MEDs and two alternative ways to assess erythema.Patients and methodsCross-sectional study of 113 individuals in Bogotá, Colombia. We used a solar simulator to measure UV-A radiation and combined UV-A and UV-B (UVA + UVB) radiation, o se podría suprimir este término porque UVA y UVB son términos conocidos for MED calculation. Narrowband UV-B (NBUVB) radiation was measured in a phototherapy cabin. Erythema was assessed visually and with a Mexameter MX 18 device.ResultsThe median MEDs of UVA + UVB radiation were 22 mJ/cm2 for Fitzpatrick skin types I and II, and 33 and 43 mJ/cm2, respectively, for types III and IV. The MEDs of UV-A radiation were 22, 42, 86, and 100 J/cm2 for types I, II, III, and IV, respectively. The MEDs of NBUVB light were 390, 550, 770, and 885 mJ/cm2 for the 4 skin types. The correlation between MEDs and skin types ranged from 0.5 to 0.69. Lin's concordance correlation coefficients between visual and Mexameter assessments of erythema were greater than 0.8 in all cases.ConclusionThis study allowed us to understand MED values for UV-A, UVA + UVB, and NBUVB according to different skin types in the Colombian population. Concordance correlation coefficients between the different methods of erythema assessment were very good. Correlations between MEDs and skin types were moderate to good. 相似文献
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目的:建立HPLC-紫外可见光检测器法测定安神补脑液中维生素B1的含量,以改进现行药典 标准中的方法。方法:采用安捷伦ZORBAX SB-Aq色谱柱(4.6 mm×250 mm,5 μm),以硫酸月桂酯钠溶液(5→530)-乙腈-磷酸(530∶470∶1)为流动相,体积流量为1.0 mL?min-1,检测波长为246 nm,柱温35 ℃。结果:维生素B1质量浓度在5.385~53.85 μg?mL-1范围内,线性关系良好(r=1.000);平均回收率为100.1%。HPLC-UV法测定来自5个厂家的安神补脑液中维生素B1的平均含量,分别为91. 9%、91. 8%、88. 6%、90. 6%、103. 6%。 结论:HPLC-UV法更适于测定安神补脑液中维生素B1的含量,该方法专属性好,准确、灵敏,解决了现行方法出现的问题,并简化了前处理步骤。 相似文献
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Alfredo Santovito Stefano Ruberto Gabriella Galli Costanza Menghi Marilena Girotti Piero Cervella 《Drug and chemical toxicology》2019,42(4):378-385
Oxybenzone or benzophenone-3 (2-hydroxy-4-methoxybenzophenone; BP-3) is a filter used in a variety of personal care products for protection of human skin and hair from damage by ultraviolet radiation. BP-3 is suspected to exhibit endocrine disruptive properties. Indeed, it was found to be able to interact with the endocrine system causing alteration of its homeostasis, with consequent adverse health effects. Moreover, it is ubiquitously present in the environment, mostly in aquatic ecosystems, with consequent risks to the health of aquatic organisms and humans. In the present study, we analyzed the cytogenetic effects of BP-3 on human lymphocytes using in vitro chromosomal aberrations and micronuclei assays. Blood samples were obtained from five healthy Italian subjects. Lymphocyte cultures were exposed to five concentrations of BP-3 (0.20, 0.10, 0.05, 0.025, and 0.0125?μg/mL) for 24 and 48?h (for chromosomal aberrations and micronuclei tests, respectively). The concentration of 0.10?µg/mL represents the acceptable/tolerable daily intake reference dose established by European Union, whereas 0.20, 0.05, 0.025, and 0.0125?µg/mL represent multiple and sub-multiple of this concentration value. Our results reported cytogenetic effects of BP-3 on cultured human lymphocytes in terms of increased micronuclei and chromosomal aberrations’ frequencies at all tested concentrations, including concentrations lower than those established by European Union. Vice versa, after 48-h exposure, a significant reduction of the cytokinesis-block proliferation index value in cultures treated with BP-3 was not observed, indicating that BP-3 does not seem to produce effects on the proliferation/mitotic index when its concentration is equal to or less than 0.20?μg/mL. 相似文献
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In this study, a novel poly (SMIm)-Tris-Fe3O4 nanocomposite was prepared for selective extraction of Cu+ and Cu2+ ions by ultrasound assisted-cloud point extraction (UA-CPE). The nanocomposite was characterized by analysis of ATR-FT-IR, 1H NMR and XRD. After optimization of the extraction conditions, the copper ions were independently detected against sample blank at 347 nm by micro-volume UV–vis spectrophotometer. Under the optimal conditions, good linear relationship was obtained in the ranges of 0.3−150 and 10−350 μg L−1 for each ion at pH 7.0 and pH 5.0, respectively, with a better regression coefficient than 0.992. The method detection limits, accuracy and precision were 0.095 and 3.03 μg L−1, 91.5−96.0 % and 93.0−98.5 %, and 2.5–4.5 and 3.8–7.1 % (n:5, 25 and 100 μg L−1) for Cu+ and Cu2+ ions, respectively. A preconcentration of 70-fold was obtained from 35-mL of sample. After validation, the method was successfully applied to determination of total Cu levels in lichen and mushroom samples after pre-reduction at pH 7.0, and the recoveries in the range of 90−96 % were obtained by two calibration approaches after spiking with 10 μg L−1. The results were also statistically compared with those obtained by FAAS analysis to ensure accuracy and precision. 相似文献
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目的:建立琥珀酸去甲文拉法辛缓释片释放度、含量、含量均匀度及有关物质检测方法,并进行方法学验证。方法采用紫外分光光度法测定释放度,高效液相色谱法测定含量、含量均匀度及有关物质,分别考察专属性、线性、回收率、精密度及稳定性等,进行方法学验证。结果释放度方法学验证结果显示,该方法专属性好,在10~200μg/ml范围内线性关系良好,回收率、重复性及中间精密度均符合要求;含量、含量均匀度检测方法验证结果显示,该方法专属性良好,在5~400μg/ml范围内线性关系良好,回收率、重复性及中间精密度均符合要求,溶液在24 h内稳定;有关物质方法学验证结果显示,该方法专属性好,灵敏度高,线性、回收率均符合要求,且溶液在室温条件下放置24 h稳定性良好。结论释放度检测方法简单、灵敏、专属性好、准确度高,含量及含量均匀度检测方法准确可靠,有关物质检测方法准属性好、灵敏度高,均可用于琥珀酸去甲文拉法辛缓释片的质量控制。 相似文献