Clinical characteristics and etiology of bacterial meningitis in Chinese children >28 days of age, January 2014-December 2016: A multicenter retrospective study.

OBJECTIVE: To explore the clinical characteristics and etiology of bacterial meningitis (BM) in Chinese children. METHOD: BM cases in children 28days to 18 years old were collected from January 2014-December 2016 and screened according to World Health Organization standards. Clinical features, pathogens, and resistance patterns were analyzed. RESULTS: Overall, 837 cases were classified into five age groups: 28 days-2 months (17.0%), 3-11 months (27.8%), 12-35 months (24.0%), 3-6 years (13.9%), and >6years (17.3%). Major pathogens were Streptococcus pneumoniae (S. pneumoniae, n=136, 46.9%), group B Streptococcus (GBS, n=29, 10.0%), and Escherichia coli (E. coli, n=23, 7.9%). In infants <3 months old, GBS (46.5%) and E. coli (23.3%) were most common; in children >3 months old, S. pneumoniae (54.7%), which had a penicillin non-susceptibility rate of 55.4% (36/65), was most frequent. The resistance rates of S. pneumoniae and E. coli to cefotaxime and ceftriaxone were 14.0%/40.0% and 11.3%/68.4%, respectively. All GBS isolates were sensitive to penicillin. CONCLUSIONS: The occurrence of BM peaked in the first year of life, while S. pneumoniae was the predominant pathogen in children >3months of old. The antibiotic resistance of S. pneumoniae was a concern.

Solution Cathode Glow Discharge Based on Charge Coupled Device Detector.

In 21st century, many countries pay much attention to lithium because lithium is an ideal material for green energy and light alloys as well as an important kind of strategic resources. The main source of lithium is from salt lake brine. China has rich resources of salt lake brine, but these brine resources are mainly distributed in the remote western region, which are in urgent need of portable analytical instrument for on-site exploration and exploitation. However, the available experimental techniques at present can not achieve the target of on-site analysis. Over the past decade, based on atmospheric pressure solution cathode glow discharge-atomic emission spectrometry (SCGD-AES) has been paid attention to analytical researchers because it runs without common air conditions such as fuel gas, carrier gas and vacuum environment. On the basis of previous studies of other researchers, we have developed a portable SCGD based on a charge coupled device (CCD) detector by ourselves, which is short for Li-K analyzer. The length, width, height and weight of the portable Li-K analyzer is 35 cm, 19 cm, 27 cm and 10 kg, respectively, which is very conducive to carry. This work selected the wavelength of 670.78 nm as the characteristic spectral line of Li and has established a rapid analytical method for Li in salt lake brine based on two different types of brines from Tibet. Under the optimum operating conditions, the detection limit of Li was 4 ng·mL-1 and the measured precision (RSD) was better than 2%. The analytical results of Li were much different from those obtained by inductively coupled plasma-mass spectrometry (ICP-MS) with different dilution ratios by standard curve method, which may be related to the matrix effect of solution. However, the analytical results of Li agreed well with the results obtained by ICP-MS using standard addition method, which showed that standard addition method can effectively reduce the matrix effect and improve the analytical accuracies. A great deal of experimental results showed that standard addition method could obtain accurate results of Li using only two points and can greatly reduce the workloads. This work laid a methodological foundation for on-site determination of Li in salt lake brine by the portable Li-K analyzer.

Spectral properties and laser performance of Ho:Sc2SiO5 crystal at room temperature.

Holmium doped scandium silicate (Ho:SSO) bulk crystal grown by Czochralski technique is reported. The absorption cross section of 4.8 × 10(-21) cm2 at pumping wavelength 1940 nm and emission cross section of 5.56 × 10(-21) cm2 at lasing wavelength 2112 nm were calculated, respectively. Lifetime was measured to be 1.51 ms at 300 K and 0.92 ms at 77 K. Continuous-wave laser was operated by using a diode-pumped Tm:YAP laser as pump source with central wavelength of 1940 nm. Output power of 385 mW at 2112 nm was primarily obtained.

Room temperature efficient actively Q-switched Ho:YAP laser.

We report on efficient actively Q-switched Ho:YAP laser double-pass pumped by a 1.91-microm laser. At room temperature, when the incident pump power was 20.9 W, a maximum average output power of 10.9 W at 2118 nm was obtained at the repetition rate of 10 kHz, and this corresponds to a conversion efficiency of 52.2% and a slope efficiency of 63.5%. Moreover, a maximum pulse energy of approximately 1.1 mJ and a minimum pulse width of 31 ns were achieved, with the peak power of 35.5 kW.