Theoretical Analysis the Optical Properties of Multi-coupled Silver Nanoshell Particles

The surface plasmon resonances of silver nanoshell particles are studied by Green’s function. The nanoshell system of plasmon resonances results from the coupling of the inner and outer shell surface plasmon. The shift of the nanoshell plasmon resonances wavelength is plotted against with different dielectric environments, several different dielectric cores, the ratio of the inner and outer radius, and also its assemblies. The results show that a red- and blue-shifted localized surface plasmon can be tuned over an extended wavelength range by varying dielectric environments, the dielectric constants and the radius of nanoshell core respectively. In addition, the separation distances, the distribution of electrical field intensity, the incident directions and its polarizations are also investigated. The study is useful to broaden the application scopes of Raman spectroscopy and nano-optics.     

大肠杆菌DH5α菌株感受态制备及转化率变化研究

通过氯化钙法制备大肠杆菌DH5α菌株感受态,讨论了不同保存温度和保存时间对感受态转化率的影响。结果表明,在4℃下保存,8h达到最高转化率;在-20℃和-70℃下保存,均为48h达到最高转化率。通过氯化钙法制备的DH5α菌株感受态细胞,在-20℃条件下简单保存,20d内完全可以满足一般转化研究的要求,不需要复杂的甘油、液氮处理及超低温要求。     

竹黄菌液体培养下产竹红菌素的研究

先对不同产地采集的竹黄菌进行筛选,得到优产竹红菌素的菌株,然后采用单因子和3因素3水平正交试验法对竹红菌素液体发酵条件进行优化,在优化培养基的基础上,选用不同浓度的Cr3+、Fe3+、Cu2+和Ca2+对竹红菌素进行离子调控研究。结果表明:从休宁所采集的菌株不仅生长速度最快,发酵所产的竹红菌素含量也最高;竹红菌素最佳发酵碳源是葡萄糖,最佳发酵氮源是硝酸钠,最佳培养基组合为2%葡萄糖,0.2%硝酸钠,pH7.5;Cr3+和Fe3+浓度为0.005%时竹红菌素含量均最高;0.05%的Ca2+最有利于竹红菌素的分泌;Cu2+为0.03%时竹红菌素含量达到最大值。     

安徽安庆沿江湿地陆栖蚯蚓资源调查

本文报道了安庆沿江湿地中的蚯蚓隶属3科5属12种,均为广布种,其中重庆远盲蚓Amynthas chungkin-gensis与壮伟远盲蚓Amymhas robustus为安徽首次报道.     

Polyploidy and aneuploidy of seed plants from the Qinghai–Tibetan Plateau and their biological implications

The Qinghai–Tibetan Plateau is biologically diverse, with 9556 species of vascular plants in the 2,500,000 km² plateau area. We focused on seed plants from the Qinghai–Tibetan Plateau. A total of 9321 species in the Qinghai–Tibetan Plateau were recorded. Sixty-one of these genera are Chinese endemics. Our results suggested that the flora of the Qinghai–Tibetan Plateau was characterized by relatively few polyploids, and aneuploidy was also considered as relatively rare. We inferred that aneuploidy may be affected by environmental factors and the addition or loss of centromeres. Furthermore, the highest frequency of polyploids was found among perennial herbs. Annuals had low polyploidy, and perennials had high polyploidy. Species richness was correlated with the incidence of polyploids, environmental conditions, and reproductive isolation.     

不同培养基和三种金属离子对桦褐孔菌培养菌丝体的羊毛甾醇和麦角甾醇积累的影响

Lanosterol and ergosterol are the active principles with potential pharmacological activities in Inonotus obliquus. However, the two sterols are less accumulated in cultured mycelia of the fungus. In this study, different carbon and nitrogen sources and pH levels together with three metal ions were assayed for their effects on accumulation of the two sterols in the fungus. Among the tested media the growth medium consisting of glucose (1.5%), rice powder (0.5%), yeast extract (0.4%), wheat bran (0.1%), KH2PO4 (0.01%) and MgSO4·7H2O (0.05%) with pH level at 6.5 yielded a maximum production of the two sterols, which can further be increased following the treatment of Ag+, Cu2+ and Ca2+. Supplementing Ag+ at concentrations of 0.28 and 0.35μmol partially inhibited ergosterol biosynthesis, leading to an enhanced accumulation of lanosterol, the presence of intermediates of ergosterol biosynthetic pathway and a reduced accumulation of ergosterol in cultured mycelia of I.     

Temporal separation of whale vocalizations from background oceanic noise using a power calculation

The process of analyzing audio signals in search of cetacean vocalizations is in many cases a very arduous task, requiring many complex computations, a plethora of digital processing techniques and the scrutinization of an audio signal with a fine comb to determine where the vocalizations are located. To ease this process, a computationally efficient and noise-resistant method for determining whether an audio segment contains a potential cetacean call is developed here with the help of a robust power calculation for stationary Gaussian noise signals and a recursive method for determining the mean and variance of a given sample frame. The resulting detector is tested on audio recordings containing southern right whale sounds and its performance is compared to a contemporary energy detector and a popular deep learning method. The detector exhibits good performance at moderate-to-high signal-to-noise ratio values. The detector succeeds in being easy to implement, computationally efficient to use and robust enough to accurately detect whale vocalizations in a noisy underwater environment.     

One new species of the subgenus Hexatoma (Eriocera) Macquart (Diptera,Limoniidae) from China with a key to Chinese species

One new species of the subgenus Eriocera Macquart, 1838, Hexatoma (Eriocera) cleopatroides Men, sp. n. (Southern China: Anhui) is described and illustrated. A key to all of 78 known species from China in the subgenus is provided, which was solely based on literatures. The new species is similar to Hexatoma (Eriocera) cleopatra Alexander, 1933, but distinguishes from the latter by the prescutum entirely black with two ill-defined gray stripes, by the legs with fore and middle femora brown in basal half, black in apical half, with hind femora brown in basal one-fourth, and by the wings with cells c and sc more yellowish brown than the ground color.