Search

Background Liquid-based cytology (LBC) has replaced the conventional Papanicolaou test in cervical cancer screening. The cervical swab specimens collected in LBC media can also be used for additional analyses including high-risk HPV (HR-HPV) test, DNA methylation analysis, and HPV E6/E7 mRNA test. Methods The stability, integrity, and recovery rate of cellular DNA and RNA after storage at different conditions were evaluated by a quantitative real-time PCR (qPCR) based HR-HPV test, reverse transcription qPCR (RT-qPCR), and agarose gel electrophoresis. Cervical swab specimens collected in a newly developed LBC medium, VersaMedium, and ThinPrep PreservCyt medium were processed on Hologic ThinPrep 5000 instrument. Results Cervical exfoliative cells fixed by VersaMedium exhibited good cellular morphology with intact membranes and delineated chromatin structures. Cellular DNA preserved in VersaMedium exhibited high level of stability at both room temperature and 4°C, and remained mostly intact at 4°C for up to 28 days. Cellular RNA preserved in VersaMedium maintained higher level of stability and integrity at 4°C than at room temperature. VersaMedium also showed no apparent adverse effect on the recovery rate of nucleic acids. Conclusion In addition to maintaining cellular morphology, when stored at 4°C, VersaMedium preserves cellular nucleic acids and PreservCyt medium without noticeable adverse effects on the recovery rate during purification. Therefore, VersaMedium is an appropriate LBC medium for the collection and preservation of cervical swab specimens. And VersaMedium preserved cellular nucleic acids are of such high quality that they are suitable for HR-HPV qPCR test and RT-qPCR analyses.

Express industry is currently one of the fastest-growing industries; the transition of express industry is now a trend of development in express enterprises. A theory analysis method of system engineering is applied in this paper, then we can treat the express logistics as a systems engineering to research. According to the express logistics system in China, to build the Hoare three-dimensional structure model to analyze the process development and transformation trends of modern operation mode, to be combined with the core concept of competitiveness to analysis China's modern mode of operation .The text can guide for the transformation of the China express companies at different levels, and provide a practical basis for the reorganization of the express industry.

This article aims at to invent a warning system which can be used to improve the widely spread phenomenon of pedestrians and non-motorized vehicles’ traffic violation in our country. We collected data by making researches at the cross between the North and South terminal coach station of Jinan. Analysis of psychological knowledge causes pedestrian and non-motorized vehicle traffic violation are expounded in detail.

Ultra-Dense Network (UDN) is a promising technology to cope with explosively increasing traffic demands. Delay is an important performance indicator in UDN. In this paper, we analyze the impacts of average sleeping time of BS and association radius on the mean delay in UDN. The explicit relationship between delay and the average sleeping time and association radius is presented. An M/G/1/N processor sharing vacation queueing is introduced to model small cell BS with sleeping strategy and user association, and the steady state probability of BS for each state and the association probabilities of UE are derived. The average transmission rates are obtained by using the statistical analysis under user association and dynamic traffic load. The mean delay is quantitatively studied from the perspective of probability characteristics based on all the possible association states and the corresponding transmission rates. The impacts of average sleeping time and association radius on the mean delay are analyzed and validated by simulation and numerical results.

Physical mechanism of supercontinuum generation in photonic crystal fiber by femtosecond laser pulse has been investigated experimentally. In this study, we used the tunable output wavelength Ti: sapphire optical parametric amplifier as the pump source and the fiber spectrometer acquired the spectrogram of supercontinuum generation in photonic crystal fiber under different power and wavelength conditions, then we normalized the spectrograms and make a comparison of them. PCF supercontinuum differences affected by physical mechanisms were analyzed. We found that when increasing the incident pump pulse power, the spectral width will be gradually widened, there are more peaks, part of the energy will transfer in to the short-wave- length region; as long as it reaches a certain intensity, width of supercontinuum finally saturated, the shape of supercontinuum was also stabilized. As the incident power was settled at 300 milliwatt and the length of PCF was settled at 105 millimeter, experimental results show that width and shape of supercontinuum are affected by the wavelength of pump pulse, in the range of 760 to 840 nm, there appears more and more peaks with the increase of incident wavelength; at anomalous dispersion the spectrogram of supercontinuum generation will be more flat and more wider as the wavelength of pump pulse closer to zero point.

Titania nanoparticles were anchored onto active carbon (AC) through a hydrothermal process to obtain TiO2/AC composites. The optimal TiO2 loading and hydrothermal pH were investigated. The prepared TiO2/AC composites were used as adsorbents for dibenzothiophene (DBT) from model fuel. The adsorption capacity of TiO2/AC composite in the optimal synthesis conditions has enhanced 12.4% compared with pure AC. The adsorbents were regenerated by toluene washing, and the TiO2/AC composite showed higher adsorptive capacity than AC even after three recycles. The pore structure and surface chemical proprieties of TiO2/AC composite and AC were also investigated by N2 adsorption-desorption isotherms and Beohm titration. The results indicate that the surface acidic sites of TiO2/AC may play an important role in the improved adsorption performance.

Mesoporous HPW/SiO2 modified with Ag species was used as the catalyst for the oxidative desulfurization of both model and real diesel oils. Three model diesel oils were prepared by using petroleum ether, benzene, and octene, respectively, as solvent and with dibenzothiophene (DBT) as the objective sulfur compound. The catalyst with a molar ratio of Ag to HPW being 2 (Ag2-HPW/SiO2) exhibits the highest catalytic activity; however, the catalytic activity decreases with further increase in Ag content. The results of nitrogen adsorption–desorption, X-ray diffraction, UV-vis, and energy dispersive spectroscopy show that isolated Ag+ ion is located on the modified catalyst. The modification of HPW/SiO2 with Ag species may combine the selective absorption capacity of Ag+ for sulfur compounds with the catalytic activity of HPW, which is helpful to enhance the selective oxidative desulfurization. During the desulfurization process, the sulfur compounds were first selectively adsorbed on the catalyst surface by π complexation between Ag+ and sulfur compounds, which could increase the probability of collision between sulfur compounds and catalytic active sites and then accelerate the oxidation reaction. The sulfur content in the real diesel oil can be reduced to 228 ×10−6 from the original 1800 ×10−6 over Ag2-HPW/SiO2; the desulfurization amount is 4.6% higher than that over the unmodified HPW/SiO2. In addition, the Ag-modified catalyst shows excellent reusability; after three reaction cycles, the desulfurization ratio of Ag2-HPW/SiO2 is only slightly lower than that of the fresh catalyst.

A compact 500.9 nm laser was realized using doubly resonant intracavity sum–frequency mixing. An Nd:YAG crystal and an Nd:YVO4 crystal were employed as the gain crystals. In two sub-cavities, 946 nm radiation from the Nd:YAG and 1064 nm radiation from the Nd:YVO4 were mixed to generate 500.9 nm. In the overlapping of the two cavities, sum–frequency mixing was achieved in a type-II critical phase-matched KTP crystal. An output power of 78 mW at a wavelength of 500.9 nm was generated using a total incident pump power of 4 W and the output light exhibited low noise, with the root-mean-square value being 0.3%.

A compact, efficient yellow-orange light at 593.5 nm was realized by the intracavity sum-frequency mixing using a BIBO crystal in a diode-pumped Nd:YVO4 laser. At an incident pump power of 3.5 W, up to 126 mW of CW output light at 593.5 nm was achieved with a 1.5-mm-long critical phase-matching BIBO. The optical-to-optical conversion efficiency was up to 3.6%, which was comparable to a 5-mm-long LBO. The beam equality was excellent with an ellipticity of 0.97 and output noise of less than 0.8% (rms). Results confirm that the BIBO is an efficient material for frequency conversion in the visible region.

Background The chimeric sequences produced by phi29 DNA polymerase, which are named as chimeras, influence the performance of the multiple displacement amplification (MDA) and also increase the difficulty of sequence data process. Despite several articles have reported the existence of chimeric sequence, there was only one research focusing on the structure and generation mechanism of chimeras, and it was merely based on hundreds of chimeras found in the sequence data of E. coli genome. Method We finished data mining towards a series of Next Generation Sequencing (NGS) reads which were used for whole genome haplotype assembling in a primary study. We established a bioinformatics pipeline based on subsection alignment strategy to discover all the chimeras inside and achieve their structural visualization. Then, we artificially defined two statistical indexes (the chimeric distance and the overlap length), and their regular abundance distribution helped illustrate of the structural characteristics of the chimeras. Finally we analyzed the relationship between the chimera type and the average insertion size, so that illustrate a method to decrease the proportion of wasted data in the procedure of DNA library construction. Results/Conclusion 131.4 Gb pair-end (PE) sequence data was reanalyzed for the chimeras. Totally, 40,259,438 read pairs (6.19%) with chimerism were discovered among 650,430,811 read pairs. The chimeric sequences are consisted of two or more parts which locate inconsecutively but adjacently on the chromosome. The chimeric distance between the locations of adjacent parts on the chromosome followed an approximate bimodal distribution ranging from 0 to over 5,000 nt, whose peak was at about 250 to 300 nt. The overlap length of adjacent parts followed an approximate Poisson distribution and revealed a peak at 6 nt. Moreover, unmapped chimeras, which were classified as the wasted data, could be reduced by properly increasing the length of the insertion segment size through a linear correlation analysis. Significance This study exhibited the profile of the phi29MDA chimeras by tens of millions of chimeric sequences, and helped understand the amplification mechanism of the phi29 DNA polymerase. Our work also illustrated the importance of NGS data reanalysis, not only for the improvement of data utilization efficiency, but also for more potential genomic information.

The coupled photocatalyst SnO 2 /TiO 2 is prepared by ball milling through doping SnO 2 into TiO 2 and using H 2 O solution as disperser. The coupled photocatalyst SnO 2 /TiO 2 is characterized by the UV–vis diffuse reflection spectroscopy, X-ray photoelectron spectroscopy (XPS), X-ray powder diffraction (XRD) and transmission electron microscopy (TEM). The results show that the optimum percentage of SnO 2 doped is 5 wt.% and that the photocatalytic activity of the coupled SnO 2 /TiO 2 photocatalyst is much higher than that of TiO 2 and SnO 2 –TiO 2 without ball milling. Compared with TiO 2 , the photoexcited wavelength range of the coupled SnO 2 /TiO 2 red shifts of about 20 nm and the light absorption intensity is also improved. The crystal phase of TiO 2 is not changed and new crystal phases are not found by ball milling. SnO 2 and TiO 2 coupled highly, forming the SnO 2 /TiO 2 photocatalyst. The increased photocatalytic activity of the coupled photocatalyst may be attributed to the enhance charge separation efficiency and extend the wavelength range of photoexcitation.