84 research outputs found
Application of numerical inverse method in calculation of composition-dependent interdiffusion coefficients in finite diffusion couples
The previously developed numerical inverse method was applied to determine the composition-dependent interdiffusion coefficients in single-phase finite diffusion couples. The numerical inverse method was first validated in a fictitious binary finite diffusion couple by pre-assuming four standard sets of interdiffusion coefficients. After that, the numerical inverse method was then adopted in a ternary Al-Cu-Ni finite diffusion couple. Based on the measured composition profiles, the ternary interdiffusion coefficients along the entire diffusion path of the target ternary diffusion couple were obtained by using the numerical inverse approach. The comprehensive comparisons between the computations and the experiments indicate that the numerical inverse method is also applicable to high-throughput determination of the composition-dependent interdiffusion coefficients in finite diffusion couples
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Baculovirus superinfection: a probable restriction factor on the surface display of proteins for library screening
In addition to the expression of recombinant proteins, baculoviruses have been developed as a platform for the display of complex eukaryotic proteins on the surface of virus particles or infected insect cells. Surface display has been used extensively for antigen presentation and targeted gene delivery but is also a candidate for the display of protein libraries for molecular screening. However, although baculovirus gene libraries can be efficiently expressed and displayed on the surface
of insect cells, target gene selection is inefficient probably due to super-infection which gives rise to cells expressing more than one protein. In this report baculovirus superinfection of Sf9 cells has been investigated by the use of two recombinant multiple nucleopolyhedrovirus carrying green or red fluorescent proteins under the control of both early and late promoters (vAcBacGFP and vAcBacDsRed). The reporter gene expression was detected 8 hours after the infection of vAcBacGFP and cells in early and late phases of infection could be distinguished by the fluorescence intensity of the expressed protein.
Simultaneous infection with vAcBacGFP and vAcBacDsRed viruses each at 0.5 MOI resulted in 80% of infected cells coexpressing the two fluorescent proteins at 48 hours post infection (hpi), and subsequent infection with the two viruses resulted in similar co-infection rate. Most Sf9 cells were re-infectable within the first several hours post infection, but the reinfection rate then decreased to a very low level by 16 hpi. Our data demonstrate that Sf9 cells were easily super-infectable during baculovirus infection, and super-infection could occur simultaneously at the time of the primary infection or subsequently during secondary infection by progeny viruses. The efficiency of super-infection may explain the difficulties of baculovirus display library screening but would benefit the production of complex proteins requiring co-expression of multiple polypeptides
Primerjalna študija genetske raznovrstnosti talnih bakterij in gliv v različnih sukcesijah vegetacije na krasu v provinci Guizhou, Kitajska
To study the soil genetic diversity of bacteria and fungi in different vegetation successions (grassland, shrubbery, primary forest and secondary forest) from the karst area, the Polymerase Chain Reaction-Denaturing Gradient Gel Electrophoresis (PCR-DGGE) technology was applied. The results showed that: (1) the diversity of bacterial communities and the fungal communities in karst area were higher than non karst area in each vegetation succession. Compared with the survey from bacterial (the Shannon index was 2.97 in primary forest, 2.91 in secondary forest, 3.18 in shrubbery, 3.14 in grassland and 2.68 in non karst), fungal diversity between karst areas (the Shannon index was 3.56 in primary forest, 3.78 in secondary forest, 3.73 in shrubbery and 3.70 in grassland) and non karst areas (the Shannon index was 3.08) was more evident, which may be related to the alterations of the composition of plant community and the source of carbon in soil with the vegetation succession of karst ecosystem; (2) The comparation of bacterial diversity index and the richness comprehensively evaluated as follows: shrubbery > grassland > primary forest > nsecondary forest. The diversity index and the richness of fungal communities was as follows: secondary forest > shrubbery > grassland > primary forest. The results suggest that the fungal communities have been greatly changed via vegetation successions, but the diversity index and the richness of the bacterial communities have not been seriously affected. The results provide scientific basis for understanding karst surface ecosystem, which contributes to the future aim of protecting the karst from desertification.Za proučevanje genetske pestrosti talnih bakterij in gliv v različnih sukcesijah vegetacije (travišče, grmičevje, primarni gozd in sekundarni gozd) na krasu je bila uporabljena tehnologija verižne reakcije s polimerazo-denaturirajoča gradientna gelska elektroforeza (PCR-DGGE). Rezultati raziskave so pokazali, da: (1) je bila v vsaki sukcesiji vegetacije pestrost bakterijskih in glivnih združb na kraškem območju višja kot na nekraškem. V primerjavi z bakterijsko raznovrstnostjo (Shannonov indeks je bil 2,97 v primarnem gozdu, 2,91 v sekundarnem gozdu, 3,18 v tleh grmičevja, 3,14 v tleh travišč in 2,68 v nekraškem območju) je bila raznovrstnost gliv med kraškimi območji (Shannonov indeks je bil v primarnem gozdu 3,56, 3,78 v sekundarnem gozdu, 3,73 v tleh grmičevja in 3,70 v tleh travišč) in nekraškimi (Shannonov indeks je bil 3,08) jasneje izražena. To je lahko povezano s spremembami v sestavi rastlinske združbe in vira ogljika v tleh glede na stanje sukcesije v vegetaciji kraškega ekosistema. (2) Primerjava kazalnikov bakterijske raznovrstnosti in abundance je bila celostno ovrednotena in sledi takole: grmičevje > travišče > primarni gozd > sekundarni gozd. Kazalnika raznovrstnosti in abundance glivnih združb kažeta sledeči trend: sekundarni gozd > grmičevje > travišče > primarni gozd. Rezultati izkazujejo, da so se glivne združbe precej spremenile zaradi sukcesije v vegetaciji, vendar pa na drugi strani ni bilo bistvenega vpliva na kazalnika bakterijske raznovrstnosti in abundance. Rezultati med drugim dajejo tudi znanstveno podlago za razumevanje delovanja kraškega površinskega ekosistema, kar ključno prispeva k cilju zaščite krasa pred dezertifikacijo (širjenjem puščav)
A Radar Emitter Recognition Mechanism Based on IFS-Tri-Training Classification Processing
Radar Warning Receiver (RWR) is one of the basic pieces of combat equipment necessary for the electromagnetic situational awareness of aircraft in modern operations and requires good rapid performance and accuracy. This paper proposes a data processing flow for radar warning devices based on a hierarchical processing mechanism to address the issue of existing algorithms’ inability to balance real-time and accuracy. In the front-level information processing module, multi-attribute decision-making under intuitionistic fuzzy information (IFS) is used to process radar signals with certain prior knowledge to achieve rapid performance. In the post-level information processing module, an improved tri-training method is used to ensure accurate recognition of signals with low pre-level recognition accuracy. To improve the performance of tri-training in identifying radar emitters, the original algorithm is combined with the modified Hyperbolic Tangent Weight (MHTW) to address the problem of data imbalance in the radar identification problem. Simultaneously, cross entropy is employed to enhance the sample selection mechanism, allowing the algorithm to converge rapidly
A Radar Emitter Recognition Mechanism Based on IFS-Tri-Training Classification Processing
Radar Warning Receiver (RWR) is one of the basic pieces of combat equipment necessary for the electromagnetic situational awareness of aircraft in modern operations and requires good rapid performance and accuracy. This paper proposes a data processing flow for radar warning devices based on a hierarchical processing mechanism to address the issue of existing algorithms’ inability to balance real-time and accuracy. In the front-level information processing module, multi-attribute decision-making under intuitionistic fuzzy information (IFS) is used to process radar signals with certain prior knowledge to achieve rapid performance. In the post-level information processing module, an improved tri-training method is used to ensure accurate recognition of signals with low pre-level recognition accuracy. To improve the performance of tri-training in identifying radar emitters, the original algorithm is combined with the modified Hyperbolic Tangent Weight (MHTW) to address the problem of data imbalance in the radar identification problem. Simultaneously, cross entropy is employed to enhance the sample selection mechanism, allowing the algorithm to converge rapidly
Specific Emitter Identification via Bispectrum-Radon Transform and Hybrid Deep Model
Specific emitter identification is a technique that distinguishes different emitters using radio fingerprints. Feature extraction and classifier selection are critical factors affecting SEI performance. In this paper, we propose an SEI method using the Bispectrum-Radon transform (BRT) and a hybrid deep model. We propose BRT to characterize the unintentional modulation of pulses due to the superiority of bispectrum distributions in characterizing nonlinear features of signals. We then apply a hybrid deep model based on denoising autoencoders and a deep belief network to perform further deep feature extraction and discriminative identification. We design an automatic dependent surveillance-broadcast signal acquisition system to capture signals and to build dataset for validating our proposed SEI method. Theoretical analysis and experimental results show that the BRT feature outperformed traditional features in characterizing UMOP, and our proposed SEI method outperformed other feature and classifier combination methods
Gap analysis of Firmiana danxiaensis, a rare tree species endemic to southern China
Firmiana danxiaensis (F. danxiaensis) is a special native species with a narrow distribution. More than 90 % of the plant species in the genus that F. danxiaensis belongs to are rare species with a narrow distribution. The main distribution area is Mount Danxia, a representative area of China Danxia where many endemic species of the Danxia landform have been bred. We carried out a gap analysis by overlapping the nature reserves with the potential habitat of F. danxiaensis. The results show that: (1) the potential habitat area of F. danxiaensis is 6,255.28 km2 simulated by the Biomod2 ensemble model and 4,114.19 km2 by Maxent, respectively, which accounted for 3.48 % and 2.29 % of the study area, located in Nanxiong county, Shixing county, Renhua county, and Qujiang county; (2) F. danxiaensis prefers areas with the max temperature of the warmest month over 32.5℃, the temperature seasonality between 6000 and 7000, and the occurrence probability of F. danxiaensis was at its highest level when the max temperature of the warmest month reached between 36 and 37 °C, the temperature seasonality was nearly 7000; (3) more than 40 % of the potential habitat of F. danxiaensis was anthropogenically disturbed; (4) in the potential habitat simulated by Maxent, the conservation gap area is 3,390.26 km2, accounting for 82.40 % of the total potential habitat, in the potential habitat simulated by Biomod2 ensemble model, the conservation gap area is 4.899.62 km2, accounting for 78.33 % of the total potential habitat. The protection status of F. danxiensis is poor, with populations of F. danxiaensis in Yingde and Shixing not covered by nature reserves and already subject to serious human disturbance. It is recommended that the structure of existing protected areas be adjusted, the scope of corresponding nature reserves be appropriately expanded, and new nature reserves be added to ensure the sustainable development of F. danxiaensis populations
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