[Detection System for High-Resolution and Broadband-2D Spectrogram].

In order to meet the demand of detecting the high-resolution and broadband-2D spectrogram for echelle-prism cross-dispersion, the design method is given, and the 2D spectrogram detection system with high-resolution and low noise is designed by analyzing the relation between the detector and the optical system and proving designing method of detecting the area spectrogram. The system includes a main control unit, a detector driving unit, a signal processing unit, a data storage unit and a data transmission unit, etc. With Hamamatsu's S10141-1109S CCD as the detector, the detection system features high sensitivity, broadband spectrogram, high signal to noise ratio. Combined with the echelle-prism cross-dispersion optical path to perform experiments, the results show that, the detection system can acquire high-resolution 2D spectrogram image in the range of 200 to 600 nm, the monochromatic image at 253.652 nm of Hg lamp covers 5 pixels, and the resolvable wavelength reaches 6.3 pm.

[Optical path difference in off-plane quasi-Littrow dispersion mountings].

The present paper analyzes the relative relation between the meridian and sagittal rays in off-plane quasi-Littrow (OP-QL) dispersion mountings. It's concluded that the off-plane angle will cause the rotation of the beam and result in the mismatch between the sagittal beams on different optical elements. Therefore the total optical path difference (OPD) should be an accumulation of corresponding beams instead of the sagittal beam of each element itself. Then, a directional derivative based method is put forward to calculate the OPD for spherical mirrors in various directions. Based on the method, the numerical OPD for OP-QL mountings is solved. Finally, this methodology is validated with both echelette and echelle examples.

Use of next generation sequence to investigate potential novel macrolide resistance mechanisms in a population of Moraxella catarrhalis isolates.

Although previous studies have confirmed that 23S rRNA gene mutation could be responsible for most of macrolide resistance in M. catarrhalis, a recent study suggested otherwise. Next generation sequence based comparative genomics has revolutionized the mining of potential novel drug resistant mechanisms. In this study, two pairs of resistant and susceptible M. catarrhalis isolates with different multilocus sequence types, were investigated for potential differential genes or informative single nucleotide polymorphisms (SNPs). The identified genes and SNPs were evaluated in 188 clinical isolates. From initially 12 selected differential genes and 12 informative SNPs, 10 differential genes (mboIA, mcbC, mcbI, mboIB, MCR_1794, MCR_1795, lgt2B/C, dpnI, mcbB, and mcbA) and 6 SNPs (C619T of rumA, T140C of rplF, G643A of MCR_0020, T270G of MCR_1465, C1348A of copB, and G238A of rrmA) were identified as possibly linked to macrolide resistance in M. catarrhalis. Most of the identified differential genes and SNPs are related to methylation of ribosomal RNA (rRNA) or DNA, especially MCR_0020 and rrmA. Further studies are needed to determine the function and/or evolution process, of the identified genes or SNPs, to establish whether some novel or combined mechanisms are truly involved in M. catarrhalis macrolide resistance mechanism.

Rapid detection and identification of infectious pathogens based on high-throughput sequencing.

BACKGROUND: The dilemma of pathogens identification in patients with unidentified clinical symptoms such as fever of unknown origin exists, which not only poses a challenge to both the diagnostic and therapeutic process by itself, but also to expert physicians. METHODS: In this report, we have attempted to increase the awareness of unidentified pathogens by developing a method to investigate hitherto unidentified infectious pathogens based on unbiased high-throughput sequencing. RESULTS: Our observations show that this method supplements current diagnostic technology that predominantly relies on information derived five cases from the intensive care unit. This methodological approach detects viruses and corrects the incidence of false positive detection rates of pathogens in a much shorter period. Through our method is followed by polymerase chain reaction validation, we could identify infection with Epstein-Barr virus, and in another case, we could identify infection with Streptococcus viridians based on the culture, which was false positive. CONCLUSIONS: This technology is a promising approach to revolutionize rapid diagnosis of infectious pathogens and to guide therapy that might result in the improvement of personalized medicine.