Sensing Liquids with an Integrated Silica Fiber THz Resonator

Our integrated silica fiber resonator was developed as a very effective way to perform X-Y sex discrimination for spermatozoa bovine semen, but it can also serve as a general purpose device for THz permittivity measurements on very small liquid samples or water-dispersed cell material, thus covering a very wide range of applications from biosensing to organic and inorganic fluid characterization. We observed a contrast in excess of 10% between an air-filled capillary and one containing water when probing a volume of just a few picoliters, as it was determined by the field concentration capability that we simulated numerically for the structure.     

Simultaneous species and sex identification of silkworm pupae using hyperspectral imaging technology

To obtain high-quality raw silk and improve the economic values of sericulture industry, sex needs to be discriminated first before cross-breeding. Much work has been reported about sex identification. However, to realize automatic separation of silkworm pupae, the species also needs to be classified, which no research has ever explored. Hence, this paper studied the feasibility of visible and near-infrared hyperspectral imaging technology to identify the species and sex of silkworm pupae. 288 hyperspectral images of silkworm pupae were collected and the average spectra were extracted from the region of interest, around the tail region of silkworm pupae. Successive projection algorithm was served as a variable selection method to choose the optimal wavelengths from the full spectra. At the same time, principal component analysis was used to choose the characteristic images. Then, the gray-level co-occurrence matrix was implemented on the first three principal component images (accounted for 99.05% of the total variances) to extract 48 textural features. Partial least squares discriminant analysis and support vector machine models were built, respectively, based on the spectral data, textural data and fusion data that included spectral and textural data, in which the support vector machine model based on the fusion data, gave the best species and sex identification result with an accuracy of 95.83%. It demonstrated that the hyperspectral imaging technology could be a new and nondestructive method to replace the manual work.     

Extinction and blow-up phenomena in a non-linear gender structured population model

In this article we consider a gender structured model in population dynamics. We assume that the fertility rate depends upon the weighted population of males instead of total population of males. The proportion of males in the population is determined by fixed environmental or social conditions. Here we prove an existence and uniqueness result for a non-trivial steady state. If the initial age distribution is uniformly below the non-trivial steady state then we show that the total population goes extinct in infinite time. On the other hand, if we take the initial age distribution to be uniformly above the steady state then the total population blows up exponentially with time.     

超高效液相色谱-串联质谱法同时测定鱼制品中残留的7种性激素

以电喷雾离子源(ESI)为电离源,在正离子采集模式下建立了鱼制品中7种性激素（甲基炔诺酮、甲基睾酮、丙酸睾酮、醋酸甲羟孕酮、醋酸甲地孕酮、醋酸氯地孕酮、诺龙）的超高效液相色谱-质谱/质谱(UPLC-MS/MS)检测方法。样品被酶解后用甲醇提取,提取液经氯化锌(ZnCl2)去脂、LC-C18和LC-NH2固相萃取柱净化、Waters ACQUITYTM UPLC BEH-C18色谱柱(100 mm×2.1 mm, 1.7 μm)分离,在多反应监测模式下进行UPLC-MS/MS分析。7种性激素的方法检出限(S/N=3)为0.08～0.17 μg/kg,定量限(S/N=10)为0.24～0.58 μg/kg。考察了内标法和基质匹配外标法对7种性激素进行定量的回收率与精密度: 添加水平为1, 4 μg/kg时,以内标法定量,7种性激素的平均回收率为76%～118%,相对标准偏差（RSD）为5.0%～11.3%;以基质匹配外标法定量,7种性激素的平均回收率为66%～94%,RSD为4.5%～10.7%。该结果表明两种方法均能够满足鱼制品中7种性激素的多残留检测要求。应用建立的方法对市售脱脂大黄鱼及烤鱼片进行检测,未发现7种目标违禁性激素。     

刺鳅性染色体的细胞遗传学确定证据

通过对刺鳅有丝分裂中期染色体的核型、Ａｇ－ＮＯＲｓ和Ｃ－带分析,以及对精母细胞减数分裂粗线期二价体配对行为的系统观察,确定刺鳅具有一对异配的大型性染色体,其性别决定属ＸＸ／ＸＹ型     

近期微流控芯片疾病诊断技术的研究进展

微流控芯片具有液流可控、样品消耗量小、反应速度快、易于集成化等特点,在临床诊断和疾病筛查领域具有广阔的发展前景。本文针对近年来微流控芯片技术在疾病诊断方面的最新研究进展,从疾病标志物检测、细胞筛选和药物代谢研究及疾病诊断微流控芯片装置的发展现状等方面概述其在疾病诊断方面的应用和发展。     

昆虫信息素的研究(Ⅴ)——家蝇性诱剂(Z)-9-二十三碳烯的合成

1971年Carlson等首先从雌性家蝇(Musca domestica)表皮类脂物和粪便类脂物中分离、鉴定并且合成了(Z)-9-二十三碳烯^[1],命名为muscalure,这个化合物对雄蝇具有引诱作用,其后陆续报道了这个化合物的一些合成方法^[2-6],其中美国Zoecon公司Carney等使用易得的油醇为原料,经甲基磺酰氯-三乙胺处理转变成甲基磺酸油酯,在铜盐催化下与正戊基镁溴化物偶联的方法提供了该产品商品化生产的路线^[6].     

A novel polyfunctional chiral building block derived from (S)-ethyl lactate. Application to the synthesis of the sex pheromone of the southern corn rootworm (Diabrotica undecimpunctata howardi)

Highly enantiomerically pure (4S, 5E)-4-bromomethylhept-5-enenitrile was prepared from (S)-ethyl lactate by a six-step procedure involving a rearrangement of chiral cyclopropylcarbinol. This product was used for the synthesis of the sex pheromone of the southern corn rootworm (Diabrotica undecimpunctata howardi), (10R)-10-methyltridecan-2-one. For preliminary communication, see Ref. 1. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 151–155, January, 2000.     

Influence of preparation conditions on properties of chemical modified nylon affinity membrane (used for γ-globulin adsorption)

Microporous polyamide membrane (Nylon 6, PA) was modified by add hydrolysis and then coupled with hydroxyethyl cellulose (HEC) to amplify reactive groups and reduce nonspecific interaction with proteins. 1,6-Diaminohexane (DAH) as space arm and phenylalanine (Phe) as ligand were immobilized onto nylon membrane through the activation of s-triazine trichloride (CyCl3). The affinity membrane obtained can be used to adsorb γ-globulin specifically. The optimum conditions of preparing affinity membrane and adsorbing bovine γ-globulin were studied.     

Iridoid Sex Pheromone Biosynthesis in Aphids Mimics Iridoid-Producing Plants

Biosynthesis of (1R,4aS,7S,7aR)-nepetalactol ( 1 ) and (4aS,7S,7aR)-nepetalactone ( 2 ) in plants involves iridoid synthase (ISY), an atypical reductive cyclase that catalyses the reduction of 8-oxogeranial into the reactive enol of (S)-8-oxocitronellal, and cyclization of this enol intermediate, either non-enzymatically or by a nepetalactol-related short chain dehydrogenase enzyme (NEPS) that yields the nepetalactols. In this study, we investigated the biosynthesis in vivo of 1 and 2 in the pea aphid, Acyrthosiphon pisum, using a library of isotopically-labelled monoterpenoids as molecular probes. Topical application of deuterium-labelled probes synthesized from geraniol and nerol resulted in production of ²H₄−lactol 1 and ²H₄−lactone 2 . However, deuterium incorporation was not evident using labelled probes synthesized from (S)-citronellol. These results suggest that iridoid biosynthesis in animals, specifically aphids, may follow a broadly similar route to that characterised for plants.