Practical use of response surface methodology for optimization of veterinary antibiotic removal using UV/H2O2 process

Three of the most commonly used veterinary antibiotics—enrofloxacin (ENR), sulfamethoxazole (SMX), and oxytetracycline (OTC)—were chosen as representative antibiotics for UV/H₂O₂ treatments. The objective was to determine the optimization of UV/H₂O₂ to remove antibiotics from aquaculture discharge water using response surface methodology. The degradation of the antibiotics was investigated under varying UV/H₂O₂ conditions in environments with different levels of pH, water matrices, humic acid, and constituent ions. The degradation results demonstrated that increasing the H₂O₂ dosage facilitated ENR degradation at a neutral pH while facilitating degradation of SMX and OTC at a slightly acidic pH. The optimum removal conditions for ENR, which was used in all influential effect experiments and the contact tank experiments, was obtained at 10 mM H₂O₂, a pretreated COD of 87.51 mg L⁻¹, and an initial pH of 6.15. Among the tested anions, only the presence of Cl^- showed slight positive effects on ENR degradation, due to the generation of secondary active radicals. During the reaction, the hydroxyl radical (OH) was present at a higher pH while singlet oxygen (¹O₂) was slightly present at a lower pH. The experimental results from H₂O₂ sequential addition indicated that freshly added H₂O₂ could quench the recently generated OH and therefore a high H₂O₂ concentration with frequent adding was not necessary. Our contact system reduced the ENR concentration in both the effluent reservoir and in the UV irradiation zone. The overall results supported the use of the UV/H₂O₂ system to treat remnant antibiotics in the discharge water.     

Effects of management, environment and landscape conditions on establishment of hardwood seedlings and saplings in central Japanese coniferous plantations

There is an increasing need to restore natural hardwood forests in landscapes dominated by monocultural conifer plantations. A convenient restoration approach is to exploit natural regeneration processes. Natural regeneration, however, is affected by diverse interacting factors, for which better understanding is required, in order to optimize restoration programs. To identify optimal management practices for improving natural regeneration of hardwood trees in coniferous plantations, we examined the effects of multiple factors on the abundance of seedlings, small saplings and large saplings (height <0.3, 0.3-1.3 and ?1.3 m, respectively) of hardwood tree and shrub species in both line thinned (LT) and unthinned (UT) plantations of sugi (Cryptomeria japonica) and hardwood forests (HF) in central Japan. The effects of management practices (number of the times of weeding and cleaning, thinning method, years after thinning and forest age), environment (slope position, slope angle and canopy openness), and landscape conditions (distance from nearest hardwood forest, altitude and landuse before planting) on the number of hardwood individuals were examined by using the data obtained from the LT plantations. We also compared hardwood density between LT and UT plantations to examine the effect of line thinning. Finally, we examined species composition of LT plantations and HF to identify hardwood forest components in the thinned plantations. The effects on hardwood regeneration of environmental conditions, landscape factors and management practices applied in the plantations varied, depending on the size class and life form of the regenerating species. The abundance of large saplings of tall tree species was affected by several management factors, especially number of the times of weeding. Landscape conditions (distance from the nearest hardwood forest and altitude) affected the abundance of small saplings and seedlings of tall tree species, but not the other classes. Seedlings and small saplings of many tall tree species that contribute to hardwood forest canopies were less abundant in the LT plantations. The results show that numerous factors affect the establishment and abundance of naturally regenerating hardwood tree species, and suggest that successful establishment during early plantation stages can have long-lasting effects on natural regeneration of tall tree species.     

高粱抗旱机理研究进展

从形态抗性、渗透调节、光合作用等几个方面综述了抗旱作物高粱近年来抗旱机理的研究和进展情况。     

资源植物野生金荞麦的研究进展

中国地大物博，有30000多种高等植物，居北半球之首，其中资源植物十分丰富，也是天然药物主产国之一。自20世纪70年代以来，中国的资源植物研究尤其是药用植物的研究发展迅猛，近20年来，从天然产物中开发各种新药成为世界科学家研究的热点。中国是世界荞麦的起源中心，也是遗传多样性中心。野生金荞麦（Fagopyrum dibotrys）系蓼科荞麦属多年生草本植物，原产于中国西南，分布于陕西、江苏、浙江、江西、河南、湖北、湖南、广西、广东、四川、重庆及云南等省区，是一种营养丰富并具有重要药用价值的资源植物。野生金荞麦中蕴涵着丰富的优异基因，作为中国重要的传统中药材，金荞麦的块根活性提取物（植物次生代谢产物）具有显著的抗癌，抑制肿瘤细胞肺侵袭和转移，以及消炎抗菌等重要作用，是多种有效药物的主要成分之一。除此之外，由于其籽粒蛋白质的组分全，必需氨基酸含量高，富含维生素和微量元素，使其成为一种较理想的保健食品的选用成分。目前，由于人工栽培产量的限制，加之栽培品种在营养价值上、药用有效活性成分和效价上均低于野生品种，这就造成了对野生金荞麦资源的大量需求，从而对野生资源造成了极大的破坏。鉴于此，中国现已将其列为国家二级保护植物。国内外已经展开了资源收集、多样性、生理特性、育种、药效学以及生态环境等方面的研究，基于活性成分合成的功能基因的研究，国内外还未见报道，为了进一步开发野生金荞麦的利用价值，发掘其优异的功能基因，并保护其野生基因资源，综述了野生金荞麦在本草、原植物分类及分布、多样性、核形、化学及功能成分、药理药效、生态环境、栽培及组织培养方面研究的新进展，并从基础研究、组织培养、基因工程、抗癌机理研究、育种研究、保健品开发等方面作了展望。     

镉对植物光合作用及氮代谢影响研究进展

镉是毒性最强的环境污染物之一。植物中积累的镉可通过食物链进入人体,给人类健康带来潜在危害。镉能抑制植物生长,能使植物形态、生理生化及结构发生改变。镉可减少净光合速率,损伤光合器官;使叶绿素含量下降;抑制气孔开放,从而影响植物的光合作用;镉通过改变植物硝酸还原酶(NR)、谷胺酰氨合成酶(GS)、谷氨酸合成酶(GOGAT)以及谷氨酸脱氢酶(GDH)的活性,进一步影响植物氮代谢过程。光合作用及氮代谢在植物生长发育过程中起着十分重要的作用,综述了重金属镉对植物光合作用及氮代谢的影响,并对其机理进行了探讨。     

湿地碳氮磷的生物地球化学循环研究进展

湿地生物地球化学循环研究是湿地研究的核心内容,是研究其物理过程、化学过程和生物过程及其相互关系以及这些过程与湿地功能的关系。介绍了生物地球化学循环的概念。对N、P、C三个主要无素的生物地球化学循环研究进展进行了评述,并对生物地球化学循环研究的前景进行了简要的分析。     

大戟科植物二萜化合物药理活性的研究进展

综述了国内外大戟科植物二萜化合物的活性成分及药理活性的研究进展,该科植物所含有的二萜类成分具有显著的抗肿瘤、杀虫杀菌、抗溃疡等药理活性,值得进一步研究。     

暖冬对皖北地区小麦生育前期若干指标的影响

研究了暖冬对皖北地区小麦生育前期若干指标的影响.结果表明,暖冬导致生育前期旺长,形成过多的茎蘖数、较大的群体叶面积及较高的干物质积累量;暖冬使小麦生育进程提前,麦苗抗冻性降低,遭遇低温时易遭受冻害,废弃物含量增加.     

竹质活性炭制备的研究进展

分析了1989年以来,国内竹质活性炭制备研究概况,综述了KOH活化法、H3PO4活化法、ZnC l2活化法和水蒸汽活化法制备竹质活性炭的工艺和机理研究进展,通过比较,认为环保型水蒸汽法是常规竹质活性炭制备的发展方向;并提出今后的研究可在三个方面加强:一是全面、系统地研究各因素及因素间的交互作用以深化制备工艺的研究;二是引入新技术以拓展制备技术的研究,三是以应用需要推动制备技术的研究。     

禽流感研究进展

近年来禽流感的大范围流行,造成了巨大的经济损失并严重威胁着人类健康,因此禽流感的研究越来越被人们重视。本文就目前禽流感流行状况、检测方法进行综述。