Ball Tips of Micro/Nano Probing Systems:A Review

To satisfy the measuring demands for the micro components of the industry, micro/nano probing systems with various ball tips have been developed. However, most of them cannot be used to measure the real micro geometrical features high precisely because the parameters of the ball tips are not appropriate. The ball tips with a diameter of less than 100 μm, a sphericity and eccentricity of far less than 1 μm are required urgently. A review on the state-of-the-art of ball tips of micro/nano probing systems is presented. The material characteristics and geometric parameters of now available ball tips are introduced sepa- rately. The existing fabrication methods for the ball tips are demonstrated and summarized. The ball tips＇ future trends, which are smaller diameter, better sphericity and smaller eccentricity, are proposed in view of the practical requirements of high-precision measurement for micro geometrical features. Some challenges have to be faced in future, such as the promotion and high-precision measurement for the small ball tip＇s sphericity and eccentricity. Fusion method without the gravity effect when the molten ball tip solidifying is a more suitable way to fabricate a small diameter ball tip together with a shaft.

牛胰岛素样生长因子-1受体的生物信息学分析

以NCBI数据库中牛等9种哺乳动物的IGF-1R的蛋白序列和基因序列为研究对象,利用生物信息学的相关软件和网站,综合分析它们的IGF-1R基因序列和蛋白序列的组成结构及功能的相关性。结果表明:9种动物IGF-1R的基因序列中除了山羊和印度水牛外,其他动物均存在启动子和加尾位点;9种动物均含有开放阅读框,可编码完整的多肽链。9种动物IGF-1R的蛋白序列中氨基酸均属于酸性氨基酸,并非全部都有信号肽;除了印度水牛,牛IGF-1R的蛋白序列与其他几种动物的一致性和相似性都是在25~35之间;二级结构均以无规则卷曲为主要结构;牛的IGF-1R蛋白序列三级结构与其他几种动物的差别比较大,但结构比较稳定,9种动物的IGF-1R蛋白序列三级结构预测的模型构象符合立体化学规则。本研究为进一步探讨IGF-1R的结构和功能及动物生长发育繁殖提供一定的参考依据。

Monoclonal antibody based Dot-ELISA and indirect fluorescence antibody technique for detecting Edwardsiella ictaluri infection in yellow catfish (Pelteobagrus fulvidraco)

Edwardsiella ictaluri is known as the etiological agent of Red-head disease of yellow catfish(Pelteobagrus fulvidraco),and is the cause of heavy economic losses in the aquaculture industry.In this study,a DotEnzyme Linked Immunosorbent Assay(Dot-ELISA)and an Indirect Fluorescence Antibody technique(IFAT)for detecting Edwardsiella ictaluri were developed by using a monoclonal antibody,5D11.For DotELISA,the working dilutions of 5D11 and the secondary antisera(enzyme-labeled goat anti-mouse Ig)were 1:320 dilution and 1:3000 dilution,respectively.For IFAT,the working dilutions of 5D11 and goatanti-mouse Ig conjugated with fluorescein isothiocyanate were as respectively 1:80 and 1:256.Both of the methods established were highly sensitivity(Minimum detectable concentration,5
107 CFU/mL)and had a high degree of accuracy(positive rate was 100%for both artificial infected fish and spontaneous diseased Pelteobagrus fulvidraco).The two reliable methods developed have high potential for quick and efficient detection of Edwardsiella ictaluri in aquaculture production units.

Performance of switch between exchange bias and coercivity:Influences of antiferromagnetic anisotropy and exchange coupling

The study on temperature dependence of exchange bias field and coercivity is crucial to solving the writing/reading dilemma in magnetic recording.Motivated by recent experimental findings,a complete switch between exchange bias field and coercivity with temperature is proposed,and the performance,characterized by average switching temperature(T_(S))and switching temperature width(T_(W)),controlled by antiferromagnetic anisotropy(KAF)and exchange coupling(J_(AF))constants is studied based on a MonteCarlo simulation.The results show that a linear relationship between T_(S)and KAFis established when KAFis above a critical value,while T_(S)is weakly influenced by J_(AF).On the contrary,T_(W)is insensitive to KAF,while strongly depends on J_(AF).Besides overcoming thermal energy,the increase of KAFfor a small J_(AF)guarantees the completely frozen states in the antiferromagnetic layers during magnetizing at higher temperature,below which the exchange bias field exists with a negligible coercivity.Otherwise,for a large J_(AF),the uncompensated antiferromagnetic magnetization behavior during the ferromagnetic magnetization reversal becomes complicated,and the switching process in the low temperature range depends on the irreversibility of uncompensated antiferromagnetic magnetization reversal during magnetizing,while in the high temperature range mainly influenced by the field-cooling process,resulting in a large T_(W).This work provides an opportunity to control/optimize the performance of the temperatureinduced switch between unidirectional and uniaxial symmetries through precisely tuning KAFand/or J_(AF)to meet different application demands in the next generation information technology.

Identification and histopathological and pathogenicity analysis of Aeromonas salmonicida salmonicida from goldfish (Carassius auratus) in North China

In this study,bacterial pathogens were isolated from the liver,spleen,kidney,heart,and muscle of diseased goldfish(Carassius auratus)after a massive outbreak of disease in an aquaculture farm in Anshan,Liaoning Province,North China(N41°05′58.42″E122°53′31.89″).Based on physiological and biochemical characterization of the bacteria and 16S rDNA sequence analysis,the bacterial isolates were identified as Aeromonas salmonicida salmonicida.Virulence gene multilocus sequence typing analysis showed that the bacterial isolates from all the organs collected were of the same type,and clustered in the same phylogenetic group as A.salmonicida salmonicida.The pathogen,was named AS.17 and was resistant to rifampicin,bacitracin,vancomycin,penicillin and compound sulfamethoxazole,but was highly sensitive to nalidixic acid,lomefloxacin,spectinomycin,ofloxacin,and ciprofloxacin.Goldfish experimentally infected with AS.17 had similar symptoms to naturally infected fish,including gill filament anemia,intestinal bleeding,intra-abdominal fluid,and jaw bleeding.Histological analyses showed that the liver,the spleen,the kidney and the intestines of fish infected with AS.17 had severe pathological alterations.In summary,this study reports the isolation of A.salmonicida salmonicida from C.auratus in North China and provides a reference strain and a research foundation for further studies on A.salmonicida disease control and epidemiology.

Paper-based fluorescent devices for multifunctional assays:Biomarkers detection,inhibitors screening and chiral recognition

The development of a single analytical platform with different functions is highly desirable but remains a challenge at present.Here,a paper-based device based on fluorescent carbon dots(CDs)functionalized paper/MnO_(2)nanosheets(MnO_(2)NS)hybrid devices(PCD/NS)was proposed for single-device multi-function applications.MnO_(2)NS functioned as a fluorescence quencher of CDs and recognizer of H_(2)O_(2)released from the oxidase catalyzed system.Fluorescence recovery would occur after the decomposition of MnO_(2)NS induced by H_(2)O_(2),by which a simple and effective strategy could be developed for fluorescence monitoring multiplex biological events.Xanthine(XA)sensing,xanthine oxidase(XOD)inhibitors screening analysis and chiral recognition of glucose enantiomers were performed on PCD/NS to investigate the multifunctional application of the paper-based device.By means of PCD/NS,XA could be determined in the range of 0.1–40μmol/L with a low detection of limit of 0.06μmol/L.The IC_(50)value of allopurinol,the model inhibitor of XOD,was sensitively detected to be 7.4μmol/L.Glucose enantiomers were also recognized in terms of the specific fluorescence response to d-glucose.This work firstly presented a paper-based device capable of biomarkers detection,inhibitors screening and chiral recognition,which enlightened a promising strategy for the construction of multifunctional devices and hold the great potential application in clinical diagnosis and drug discovery.

Enhancing the immune response in the sea cucumber Apostichopus japonicus by addition of Chinese herbs Houttuynia cordata Thunb as a food supplement

The Chinese herb Houttuynia cordata Thunb(abbreviated as HCT hereafter)has been widely used in human and livestock medical research.However,few studies have tested the effects of HCT in aquaculture systems,particularly in echinoderms.In this study,the impact of HCT was evaluated when used as a feed additive to enhance the immune response of the sea cucumber,Apostichopus japonicus.Two concentrations,1.5%and 3%,of HCT powder were tested by adding them to the feed.Feeding experiments had a four week duration and each week,the humoral and cellular immunity index of the intestine,tentacles,peristome,and coelomic fluid were analyzed.The results indicated that the percentage of A.japonicus coelomocytes significantly increased after supplementing feed with HCT,and reached a peak after one week of feeding with the 3%HCT supplementation.Analysis of reactive oxygen species(ROS)indicated that HCT in feed caused a notable increase in the coelomocyte ROS concentrations over the experimental period.In both the 1.5%and 3%HCT addition groups,the ROS peaked in the third week and then remained stable.In addition,alkaline phosphatase,acid phosphatase,superoxide dismutase,lysozyme activity of the intestine,tentacles,peristome and coelomic fluid were significantly improved during the four-week test period.In conclusion,1.5%and 3%HCT added to feed boosts the immune responses of A.japonicus.HCT has potential as an immune enhancer for mariculture of sea cucumbers.