The technology of large-scale pharmaceutical plasmid purification by cetyltrimethylammonium bromide and Tritonx-114

Many methods for plasmid purification have been developed, and the whole process must be designed to remove the host RNA, protein, genomic DNA and endotoxin. Currently, plasmid is mostly purified by time-consuming chromatographies. As an alternative, a new plasmid purification technology with cetyltrimethylammonium bromide (CTAB) is described. After lysis with alkali, the CTAB was directly titrated into the supernatant for plasmid precipitation, then the coprecipitated pellets were dealt with 3 M KAc and TritonX-114. Quality detection showed that the purified plasmids were free from the contamination of host RNA. In 1 mg purified plasmid, the bacterial genomic DNA, host endotoxin and protein were less than 10 g/ mg, 50 EU/ mg and 10 g/mg, respectively. The ratio of OD260/OD280 was between 1.75 - 1.85, more than 90% of the prepared plasmid presented in the supercoiled form. Further test demonstrated that the pcDNAlacZ purified with CTAB and authoritative endotoxin-free plasmid Kit had the similar transfection efficiency in vivo and in vitro. CTAB can be used for plasmid purification; the main advantages of the DNAs purified with CTAB include the avoidance of animal-derived enzymes, toxic substance like chloroform and phenol. More attractive is that the whole process has the predominance of low cost

Switching games of stochastic differential systems

Version of RecordPublishe

Towards a better similarity measure for keyword profiling via clustering

Automatic profiling for users and postings can help law enforcement units cluster and classify users and postings effectively so that potential problematic users and postings can be identified easily. A core problem in this application is to come up with effective profiles and a good measure to compare the similarity of two profiles. In this paper, we investigate an existing keyword-based user profiling scheme and identify its limitations. Then, we propose an improved version of it and demonstrate that our proposed version is more consistent than the existing approach with respect to the observed replied rates of a user to a posting based on the similarity of the profiles. © 2013 IEEE.published_or_final_versio

Molecular characterisation of canine parvovirus strains circulating in China

Canine parvovirus (CPV) was first isolated at 1978 in the USA. Analysis of CPV isolates by monoclonal antibodies and restriction enzymes have shown that after the first emergence of CPV (CPV-2) it evolved to give rise to new antigenic types, which were designated CPV types 2a, 2b and 2c. These new types have replaced the original CPV type 2, although the proportions of each of the new antigenic types vary in different countries. In China, CPV infections were first observed in 1982, however, there has been no information concerning the antigenic types of CPV prevailing in China now. In this study, we designed a PCR assay to type canine parvovirus strains in fecal samples collected from symptomatic dogs from 2006 to 2009. Our data showed that the CPV prevalent strain is mostly 2b, the proportion of CPV-2a is very low, no CPV-2c and CPV-2 were observed

Numerical solution to independent parameter D in fluid - solid coupling equations of tube bundle with square section

2000-2001 > Academic research: refereed > Publication in refereed journalVersion of RecordPublishe

Growth of quantum dot coated core-shell anisotropic nanowires for improved thermal and electronic transport

Anisotropic nanowires are promising candidates for electronic thermal management due to their unique electrical and thermal properties.However, eco-friendly solution-processed nanomaterials with an elaborate morphology and microstructure for modulating thermal andcharge transfer are still a considerable challenge. Herein, we present a simple but effective approach for synthesizing pseudo core-shell nano-wires through quantum dot (QD)-like nanostructure coating (p-NW@QD) to generate exceptional electron-phonon transport properties.With the assistance of diphenyl ether as a coordination solvent, high crystallinity lead sulfide NWs can be fabricated with a large aspect ratiotogether with uniform QD coating. Thisp-NW@QD exhibits high electronic mobility (30.65 cm2/Vs) as well as a diameter independent lowthermal conductivity (1.5361 W/m K). Direct charge/heat carrier flow measurements and computational simulations demonstrate that theunusual electrical and thermal transport phenomenon is strongly dependent on the fast charge transport through the QD shell, and a slowphonon migration across the Umklapp process dominated NW cores. These findings indicate a significant step toward colloidal synthesisnanostructures for future high-performance nanoelectronics and thermal energy devices

Quasi-static stop band with flexural metamaterial having zero rotational stiffness

Metamaterials realizing stop bands have attracted much attentions recently since they can break-through the well-known mass law. However, achieving the stop band at extremely low frequency has been still a big challenge in the fields of elastic metamaterials. In this paper, we propose a new metamaterial based on the idea of the zero rotational stiffness, to achieve extremely low frequency stop band for flexural elastic waves. Unlike the previous ways to achieve the stop band, we found that the zero rotational stiffness can provide a broad stop band at extremely low frequency, which starts from even almost zero frequency. To achieve the zero rotational stiffness, we propose a new elastic metamaterial consisting of blocks and links with the hinge connection. Analytic developments as well as numerical simulations evidence that this new metamaterial can exhibit extremely low and broad stop band, even at the quasi-static ranges. In addition, the metamaterial is shown to exhibit the negative group velocity at extremely low frequency ranges, as well as the quasi-static stop band, if it is properly designed.ope

Cracking in asphalt materials

This chapter provides a comprehensive review of both laboratory characterization and modelling of bulk material fracture in asphalt mixtures. For the purpose of organization, this chapter is divided into a section on laboratory tests and a section on models. The laboratory characterization section is further subdivided on the basis of predominant loading conditions (monotonic vs. cyclic). The section on constitutive models is subdivided into two sections, the first one containing fracture mechanics based models for crack initiation and propagation that do not include material degradation due to cyclic loading conditions. The second section discusses phenomenological models that have been developed for crack growth through the use of dissipated energy and damage accumulation concepts. These latter models have the capability to simulate degradation of material capacity upon exceeding a threshold number of loading cycles.Peer ReviewedPostprint (author's final draft

Efficacy of praziquantel and artemisinin derivatives for the treatment and prevention of human schistosomiasis: a systematic review and meta-analysis

<p>Abstract</p> <p>Background</p> <p>Praziquantel has been used as first-line drug for chemotherapy of schistosomiasis since 1984. Besides praziquantel, artemether and artesunate have also been used for the control of this infectious disease since late 1990s. In this article, we conducted a systematic review and meta-analysis to evaluate the antischistosomal efficacy of different medication strategies including monotherapy or combination therapies of these drugs.</p> <p>Results</p> <p>A number of 52 trials from 38 articles published in peer-reviewed journals before July 2011 were selected for analysis after searching the following literature databases: the Cochrane Library, PubMed/Medline, ISI Web of Science, Chinese Biomedicine Literature Database, and China National Knowledge Infrastructure. Our meta-analyses showed that a dosage of 30-60 mg/kg praziquantel compared with placebo produced a protection rate of about 76% (95% CI: 67%-83%) for treating human schistosomiasis, which varied from 70% to 76% with no significant differences among the subspecies <it>S. haematobium</it>, <it>S. japonicum </it>or <it>S. mansoni</it>. Protection rates were higher when praziquantel doses were elevated, as concluded from the nRCTs results: the protection rate of praziquantel at 40 mg/kg was 52% (95% CI: 49%-55%), and it increased to 91% (95% CI: 88%-92%) when the dosages were elevated to 60/80/100 mg/kg divided two or more doses. Multiple doses of artemether or artesunate over 1- or 2-week intervals resulted in protection rates of 65% to 97% for preventing schistosomiasis, and increased doses and shorter medication intervals improved their efficacies. Praziquantel and artemisinin derivatives (artemether or artesunate) in combination resulted in a higher protection rate of 84% (95% CI: 64%-91%) than praziquantel monotherapy for treatment. praziquantel and artesunate in combination had a great protection rate of 96% (95% CI: 78%-99%) for preventing schistosomes infection.</p> <p>Conclusions</p> <p>According to the results, praziquantel remains effective in schistosomiasis treatment, and multiple doses would improve its efficacy; meanwhile, praziquantel is also a good drug for preventing acute schistosomiasis morbidity. It's better to use multiple doses of artemether or artesunate with 1- or 2-week intervals for prevention against schistosome infection. Praziquantel and artemether or artesunate in combination perform better in treatment than praziquantel monotherapy, and they are especially suitable for treating the patients with repeated exposure to infected water.</p