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Microbiological confirmation is rare in children with active tuberculosis; therefore, a more accurate test is needed to detect pulmonary tuberculosis in children. In this multicenter study, we evaluated the utility of the Xpert MTB/RIF Ultra (Ultra) on sputum, an assay recommended by the World Health Organization to test for childhood tuberculosis in high-burden settings. Children with symptoms suggestive of tuberculosis were enrolled at three hospitals in China and categorized as having active tuberculosis or nontuberculosis. The sensitivity and specificity of Ultra were 42.1% (48/114) and 99.0% (208/210), respectively. Using three MTB culture results as the reference, the sensitivity of Ultra in the subset of 38 children with culture-positive and 76 children with culture-negative was 68.4% (26/38) and 28.9% (22/76), respectively(p

In this study we prepared the novel compound L-isoleucine-phthalandione (LIPTA), featuring carboxyl and amide groups, and its calcium salt, the calcium salt of L-isoleucine-phthalate (LIPTA-Ca), an...

Microbiological confirmation is rare in children with active tuberculosis; therefore, a more accurate test is needed to detect pulmonary tuberculosis in children. In this multicenter study, we evaluated the utility of the Xpert MTB/RIF Ultra (Ultra) on sputum, an assay recommended by the World Health Organization to test for childhood tuberculosis in high-burden settings. Children with symptoms suggestive of tuberculosis were enrolled at three hospitals in China and categorized as having active tuberculosis or nontuberculosis. The sensitivity and specificity of Ultra were 42.1% (48/114) and 99.0% (208/210), respectively. Using three MTB culture results as the reference, the sensitivity of Ultra in the subset of 38 children with culture-positive and 76 children with culture-negative was 68.4% (26/38) and 28.9% (22/76), respectively(p 0.001). A single MTB culture combined with a single Ultra could detect 54 (54/114,47.4%) cases with active TB, while repeated MTB culture combined with a single Ultra detected 60 (60/114, 52.6%) cases with active TB(p = 0.427). Among 155 children (58 with TB and 97 with RTIs) simultaneously tested with the Ultra and Xpert MTB/RIF (Xpert), the sensitivity of the Xpert (24.1%, 14/58) was lower than that of the Ultra (41.4%, 24/58; p = 0.048). Eight children were found to have rifampin-resistant MTB strains. The Xpert MTB/RIF Ultra assay should be implemented to test for pulmonary tuberculosis in children to achieve higher confirmation rates.

Background: Bacterial meningitis (BM) remains a devastating disease in children, and it causes substantial neurological morbidity and mortality worldwide. However, there are few large-scale studies on the pathogens causing pediatric bacterial meningitis (PBM) and their antimicrobial resistance (AMR) patterns in China. The present multicenter survey summarized the features of the etiologies of BM in children and characterized their AMR patterns.Methods: Data from 1193 cerebrospinal fluid bacterial isolates from children with BM who were admitted to 13 children’s hospitals in China from 2016 to 2018 were analyzed retrospectively.Results: Of the 1142 patients with PBM, 65.9% (753) were less than 1 year old, and more than two-fifths (513, 44.9%) were younger than 3 months. The three leading pathogens causing PBM were Staphylococcus epidermidis (S. epidermidis) (16.5%), Escherichia coli (E. coli) (12.4%) and Streptococcus pneumoniae (S. pneumoniae) (10.6%). Infants under 3 months of age were at a relatively high risk of infection by E. coli (116/523; 22.2%), Enterococcus faecium (75/523; 14.3%), S. epidermidis (57/523; 10.9%), and Group B Streptococcus (55/523, 10.5%). However, Children more than 3 months of age were at a relatively high risk of infection by S. epidermidis (140/670; 20.9%), S. pneumoniae (117/670; 17.5%), and Staphylococcus hominis (57/670; 8.5%). Greater than 93.0% of E. coli isolates were sensitive to cefoxitin, piperacillin/tazobactam, cefoperazone/sulbactam, amikacin and carbapenems, and the resistance rates to ceftriaxone, cefotaxime and ceftazidime were 49.4%, 49.2% and 26.4%, respectively. From 2016 to 2018, the proportion of methicillin-resistant coagulase-negative Staphylococcus (MRCoNS) isolates declined from 80.5% to 72.3%, and the frequency of penicillin-resistant Streptococcus pneumoniae (PRSP) isolates increased from 75.0% to 87.5%. The proportion of extended-spectrum β-lactamase (ESBL)-producing E. coli fluctuated between 44.4% and 49.2%, and the detection rate of ESBL production in Klebsiella pneumoniae (K. pneumoniae) ranged from 55.6% to 88.9%. The resistance of E. coli strains to carbapenems was 5.0%, but the overall prevalence of carbapenem-resistant (CR) K. pneumoniae was high (54.5%).Conclusions: The resistance of CoNS to methicillin and the high incidence of ESBL production in Gram-negative Enterobacteriaceae pose a critical challenge to infection control. Carbapenem-resistant K. pneumoniae isolates are a serious issue for the treatment of children with PBM.

A multicenter study was performed to evaluate the value of testing gastric aspirate (GA) with Xpert MTB/RIF Ultra assay (Ultra) for childhood tuberculosis (TB) detection in China. In total, 129 children with active TB and 173 children without TB were enrolled. The sensitivity of Ultra in bacteriologically confirmed TB and probable TB cases was 87.5% (42/48) and 44.4% (36/81), respectively. The specificity of Ultra was high (99.4%, 172/173). When Ultra, culture, and acid-fast bacilli outcomes were integrated as a composite reference standard, the percentage of children with definite TB increased from 37., A multicenter study was performed to evaluate the value of testing gastric aspirate (GA) with Xpert MTB/RIF Ultra assay (Ultra) for childhood tuberculosis (TB) detection in China. In total, 129 children with active TB and 173 children without TB were enrolled. The sensitivity of Ultra in bacteriologically confirmed TB and probable TB cases was 87.5% (42/48) and 44.4% (36/81), respectively. The specificity of Ultra was high (99.4%, 172/173). When Ultra, culture, and acid-fast bacilli outcomes were integrated as a composite reference standard, the percentage of children with definite TB increased from 37.2% (48/129) to 67.4% (87/129). The sensitivity of Ultra is 80.0% (40/50) in children aged

This paper studies the callback option as an instrument to effectively mitigate congestion due to temporary surges in arrivals to a call center. The call arrival process can be an arbitrary point process, allowing uncertainty and temporary surges in the arrival rate, provided that the system is stable. When a customer arrives, the call center manager examines the system state and decides whether to offer the incoming customer the callback option or not. When the callback option is offered, the customer decides whether to accept the offer. The customer is routed to the offline queue (to be called back later) only if he is offered the callback option and accepts it. Otherwise, he is routed to the online queue. For each customer in the online queue, the call center manager incurs a waiting cost of h per time unit. Similarly, whenever she routes a customer to the offline queue (for a callback later), she incurs a one-time penalty of p. Initially, we allow complete foresight policies that look into the entire future. We show that a simple lookahead policy that looks into the future arrivals and service completion times for the next p/h time units and uses the current number of customers in the system who previously rejected a callback offer (but does not look into the accept/reject decisions of future customers) is pathwise optimal. Building on the insights gleaned from the optimal lookahead policies, we also propose a non-anticipating (and implementable) policy by interpreting the lookahead policy in the fluid model and show its optimality in the fluid model. In particular, we show that this policy reduces to the so called line policy, if the arrival rate process follows a Cox-Ingersoll-Ross process. Lastly, we conduct a simulation study which shows that the proposed policies perform well.

In this paper, we propose a fast greedy search algorithm for optimal single-cycle signal timing at individual oversaturated intersections. We illustrate the efficiency of the algorithm with a numerical example in the literature.

l-Isoleucine (l-Ile) was identified as an efficient anti-nucleating agent for isotactic polypropylene (iPP). At 0.08 wt %, l-Ile could significantly decrease the peak crystallization temperature (Tcp) of iPP by up to 8 °C at a cooling rate of 20 °C/min. Furthermore, l-Ile exhibited both anti-nucleation and pro-nucleation abilities; i.e., a low content of l-Ile inhibited iPP crystallization, whereas a high content promoted iPP crystallization. The unique crystallization behavior of iPP in the presence of l-Ile was investigated by differential scanning calorimetry, polarized optical microscopy (POM), and rheological measurement. According to POM, a low content of l-Ile completely dissolved in the iPP melt, whereas a high content of l-Ile did not. Therefore, a mechanism by which l-Ile inhibits and promotes the nucleation of iPP was proposed. Dissolving l-Ile molecules in the iPP melt hindered the homogeneous nucleation of iPP as a “dilution effect”; however, as the content increases, l-Ile could not be completely dissolved in molten iPP, and the residual crystals of l-Ile thus provided heterogeneous nucleation sites for iPP and further promoted its crystallization. Experimental evidence from rheology and POM supported this mechanism. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 135, 45956.

The storage and reduction of NO and N2O in the presence of excess O2 have been investigated over two mixed oxide catalysts. The catalysts, which were prepared via coprecipitation of solutions of mixed metal nitrates, followed by calcination, were found to have plenty storage capacities for nitrogen oxides. The storage and reduction performances varied with the catalyst composition and the duration of cycle time: the AlCoPd (1/1/0.05) mixed oxide catalyst exhibited higher efficiency for NO, and an AlCoFe (1/1/2) mixed oxide catalyst exhibited higher efficiency for N2O. The adsorptions of NO and N2O onto the mixed oxide catalysts progressed without an oxidation step, and the adsorptivity of NO surpassed that of O2. The mixed oxides showed spinel structures with sizes of 10-100 nm, and with well-developed mesopores that were formed by the evaporation of H2O and CO2 from layered double hydroxide (LDH) precursors. The storage and reduction of lean NOx and N2O over the mixed oxide catalysts were carried out via cyclic operations in a transient mode at 300 degrees C and at space velocities of around 30,000 h(-1). The removal efficiency of the cyclic operations generally increased with reduced adsorption cycle time, and reached 90% for NOx and N2O with the respective catalysts.