高效液相色谱法测定兽药龙胆泻肝散中龙胆苦苷、栀子苷和黄芩苷的含量

建立测定兽药龙胆泻肝散中龙胆苦苷、栀子苷和黄芩苷的高效液相色谱分析方法。样品经50%甲醇水溶液超声提取,C18色谱柱分离,254 nm波长下检测,外标法定量。龙胆苦苷在0.400～3.203μg范围内线性关系良好,r=0.9998,平均回收率为91.5%,RSD为0. 77%,栀子苷在0.252～2.012μg范围内线性关系良好,r=0.9999,平均回收率为90.2%,RSD为1. 58%,黄芩苷在0.500～3.981μg范围内线性关系良好,r=0.9999,平均回收率为94.6%,RSD为1.74%。该方法简单、快速、准确度高、重复性好,可以用于兽药龙胆泻肝散的质量控制。     

Changes in forest structure of a mixed conifer forest, southwestern Colorado, USA

We selected a warm/dry mixed conifer forest (ponderosa pine, white fir, Douglas-fir, and aspen) in southwestern Colorado to reconstruct historical conditions of fire regime and forest structure in preparation for an experiment in ecological restoration. Although mixed conifer forests are of high ecological and social value in the Southwest, they have been less studied than ponderosa pine forests. Fire-scar analysis on a 150-ha area showed recurring fires at mean intervals of 24 years (all fires with minimum of 2 sample trees scarred) to 32 years (fire scarring 25% or more of sample trees) from the 16th century until the abrupt cessation of fire after 1868, concurrent with European settlement. There was no evidence in age or species-specific data of severe burning at the scale of the study blocks (approximately 200 ha). The forest remained unharvested throughout most of the 20th century, until a cut in the early 1990s removed approximately equal basal areas of ponderosa pine and white fir. Forest structure had already changed substantially, however. Total basal area increased from an average of 11 m² ha⁻¹ in 1870 to 27 m² ha⁻¹ in 2003, despite harvesting of at least 8.4 m² ha⁻¹. Ponderosa pine declined from representing nearly two-thirds of basal area in 1870 to one-third in 2003. The other species increased dramatically, especially white fir, which went from 12% to 35% of basal area and dominated stand density with an average of 392 trees ha⁻¹. Total tree density increased from 142 trees ha⁻¹ in 1870 to 677 trees ha⁻¹ in 2003. The ecological changes that occurred here since the 19th century have been in exactly the opposite direction considering the warm, fire-favoring climate expected in the 21st century. If warm/dry mixed conifer forests of southern Colorado are to have a reasonable chance for persistence under the future climate regime, restoring conditions more similar to the frequently burned, open forests of the past is likely to be a useful starting point.     

Fifty years of the integrated control concept: the role of landscape ecology in IPM in San Joaquin valley cotton

In defining the integrated control concept, Stern, Smith, van den Bosch and Hagan described ‘understanding the ecosystem’ as a key underpinning of the concept. In following years, Stern and van den Bosch continued to refine and expand the role of the ecological landscape. They and their colleagues developed cultural practices that took advantage of this understanding to limit the need of pesticide intervention in cotton in the San Joaquin Valley during the 1960s and 1970s. Research and extension activities in the intervening years built upon those fundamental concepts using geospatial tools and analytical techniques to refine current understanding and develop ecological landscape level approaches to manage Lygus hesperus (Knight) in San Joaquin Valley cotton, Gossypium hirsutum (L.) and more recently G. barbadense (L.). The result has been a significant drop in insecticide use against L. hesperus, with less than one application per season during the 1990s and early 2000s. Copyright © 2009 Society of Chemical Industry     

Predictors of Chinook salmon extirpation in California’s Central Valley

Abstract Chinook salmon, Oncorhynchus tshawytscha (Walbaum), populations have declined rapidly along the western coast of North America since the year 2000, possibly because of factors such as habitat loss, altered hydrology and barriers to migration. However, few analyses have rigorously examined which of these factors actually explain historical patterns of extirpation. Data were compiled on flow regimes, habitat loss and migration barriers for 27 streams that historically supported autumn run salmon and 22 streams that supported spring runs. The probability of extirpation in streams supporting autumn run was predicted solely by migration barriers. All other factors were >10⁵ times less likely to explain existing variation. By contrast, models for spring run salmon suggest that habitat loss and altered flow regimes were also predictors of extirpation. These results suggest that regional extirpation of Chinook salmon has been driven by multiple forms of environmental change, and restoration efforts must address a multitude of bottlenecks that now impact spring and autumn run populations.     

三江源玛珂河林区寒温性针叶林优势草本种间联结研究

三江源自然保护区玛珂河林区的草本植物对寒温性针叶林的早期演替和生态恢复有着十分重要的影响。该文通过χ2统计量检测、共同出现百分率和联结系数方法,对40块寒温性针叶林样地中的22种优势草本的种间联结性进行定量分析,结果表明:231对优势草本组合中,有118对呈现正联结,其中有8对呈极显著正联结（P0.01）,6对呈显著正联结（P0.05）;负联结有112对,仅有2对优草本物种呈显著负联结（P0.05）;完全独立的有1对。可见,玛珂河林区寒温性针叶林中,超过一半的草本物种的生态学和生物学特性相似,表现为正联结,并且未达到显著水平;同时也有接近一半的优势草本物种之间竞争有限的环境资源而产生竞争和排斥。      

Browsing down our natural heritage: Deer impacts on vegetation structure and songbird populations across an island archipelago

Declines in forest and woodland birds have largely been attributed to habitat loss and fragmentation. In the past decade, however, the potential for herbivores to influence bird species abundance and community composition via their direct impact on vegetation structure has also been recognised. We tested the hypothesis that deer influence vegetation structure and bird assemblages in a large island archipelago in western North America using surveys of 18 islands with deer densities ranging from 0 to over 1 deer/ha. Amongst these islands, reduced predation and hunting pressure has allowed deer populations to increase above those likely to have existed in pre-European times. Our results support a growing body of evidence that deer regulate both the cover and architecture of understory vegetation which in turn profoundly affects island bird assemblages. Deer-free islands supported the most abundant and diverse bird fauna. Iconic songbirds such as the rufous hummingbird, song and fox sparrow were abundant on islands with no deer but substantially reduced on islands with high deer densities. Only one bird species, the dark-eyed junco, preferred moderate and high density deer islands. Our observations suggest that current cohorts of palatable shrubs on islands with high deer densities are relatively old and potentially represent an impending extinction debt, where the full effects of high deer density on island biota may take decades to fully unfold. Our results suggest that deer densities below a threshold of 0.1 deer/ha should allow native vegetation to recover and a rich and diverse bird species assemblage to persist. We suggest that adaptive management be used to test the validity of this threshold, and that without active management of deer abundance, local extinctions of native flora and fauna appear likely to accelerate.     

HPLC法同时测定金叶清瘟散中绿原酸和咖啡酸的含量

为了建立一种同时测定金叶清瘟散中绿原酸和咖啡酸的高效液相色谱法,选用Agilent C18色谱柱（250 mm×4.6 mm,5μm）,乙腈∶0.4%磷酸溶液（12∶88）等度洗脱,进样量10μL,流速1 mL/min,波长为328 nm进行检测。结果显示,被测物质能与样品中杂质有效分离,绿原酸和咖啡酸分别在5.0~500μg/mL和2.5~250μg/mL的范围内呈良好线性关系,两种药物的添加回收率均高于95%,RSD小于2%。该方法简便、快速、准确,适用于金叶清瘟散中绿原酸和咖啡酸的同时检测。     

凉血解毒汤治疗血热型寻常型银屑病临床观察

目的观察凉血解毒汤治疗血热型寻常型银屑病的临床疗效和安全性。方法 30例血热型寻常型银屑病患者,给予口服凉血解毒汤治疗6周,通过观察患者治疗前后受累体表面积(BSA)和病情严重程度指数(PASI)评分以及皮肤病生活质量指数(DLQI)评分进行疗效评定;并且通过检测治疗前后患者血尿常规、肝肾功能、心电图进行安全性评估。结果治疗后患者BSA、PASI评分及DLQI评分均较治疗前明显降低,差异具有统计学意义(P<0.05)。治疗总有效率为93.3%,无明显的不良反应。结论凉血解毒汤治疗血热型寻常型银屑病具有较好疗效,且安全性良好,值得临床推广应用。 更多还原     

张晓甦教授运用内外合治法治疗宫颈高危型HPV感染经验

高危型HPV感染致宫颈病变的发病率越来越高,张晓甦教授认为本病病位在冲任二脉,连及肝经;病因为湿、热、毒;治疗上主要以清热利湿、解毒散瘀为主,制定基本方清带解毒汤,根据湿热毒的偏盛,随证加减用药。内服配合外敷,临床疗效甚佳。     

咳喘三效散对畜禽呼吸道综合征临床防治效果研究

咳喘三效散由麻黄、鱼腥草、杏仁、甘草、石膏等中药按一定比例配制而成,主要用于防治畜禽呼吸道疾病。本试验探讨了支原净＋强力霉素、泰乐菌素＋阿莫西林、咳喘三效散分别按治疗剂量与预防剂量对畜禽呼吸道综合征的治疗及预防效果。结果表明,咳喘三效散对畜禽呼吸道综合征的防治效果最佳,且使用方便,副作用小,可作为防治畜禽呼吸道综合征的首选药物。