Background: Tissue inhibitor of metalloproteinase-2 (TIMP-2) and insulin-like growth factor binding protein 7 (IGFBP7) are recently identified urinary biomarkers of acute kidney injury (AKI) in critically ill patients. Because their predictive accuracies vary widely, a meta-analysis was performed to evaluate the accuracy of previously reported urinary TIMP-2 and IGFBP7 cut-offs for predicting AKI. Methods: This meta-analysis was reported following the guideline of PRISMA. Four databases, PubMed, the Cochrane Library, the ISI Web of Knowledge, and Embase, were systematically searched from inception to June 2018 by 2 investigators, who independently selected studies, extracted relevant data, and evaluated study quality. A bivariate model was used to calculate the pooled estimates. Results: The search identified 5 studies with 1619 critically ill patients. Urinary TIMP-2 and IGFBP7 cut-off points of 0.3 (ng/ml) 2 /1000 had a sensitivity of 0.89 [95% confidence interval (CI) 0.85–0.93], a specificity of 0.48 (95% CI 0.45–0.51) and a diagnostic odds ratio (DOR) of 8.33 (95% CI 5.55–12.52). The area under the curve (AUC) estimated by the summary receiver operating characteristic (SROC) curve was 0.748. Based on 891 critically ill patients from 4 studies, urinary TIMP-2 and IGFBP7 cut-off points of 2.0 (ng/ml) 2 /1000 had a sensitivity of 0.45 (95% CI 0.37–0.53), a specificity of 0.93 (95% CI 0.91–0.95) and a DOR of 11.43 (95% CI 7.43–17.57). The AUC estimated by SROC was 0.844. Conclusion: Cut-off values around 0.3 (ng/ml) 2 /1000 (high sensitivity) and 2.0 (ng/ml) 2 /1000 (high specificity) could be accurate surrogate biomarkers predicting AKI in critically ill patients. The urinary TIMP-2 and IGFBP7 cut-off point of 2.0 (ng/mL) 2 /1000 appears to have the highest overall accuracy. Trial registration: PROSPERO registration number 2018: CRD42018084457 Registered on 11 February 2018.

An unprecedented nickel-catalyzed reductive 1,2-dialkynylation of alkenes bearing an 8-aminoquinoline directing group has been developed. This method proceeded through a migratory insertion/reductive-coupling process under mild conditions with a wide substrate scope and good functional group tolerance, providing direct access to the synthetically flexible 1,5-diynes. Moreover, the 1,2-dialkynylation products could be further converted to borate-ester- or azide-functionalized 1,5-dienes, ditriazole, β-diyne primary amide, and trisubstituted benzene.

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Resistance to only ertapenem is an unusual phenotype of carbapenem-resistant Klebsiella pneumoniae (CRKP). This study aimed to investigate the molecular epidemiology and underlying mechanism involved in ertapenem resistance of K. pneumoniae strains that are susceptible to meropenem and imipenem. Among the 697 K. pneumoniae strains isolated from 11 grade A hospitals in China, 245 were CRKP strains, of which 18 strains resistant only to ertapenem were isolated. The genotypes, phenotypes, drug resistance homology, and drug sensitivity were analyzed; moreover, the expressions of efflux pump components and outer membrane proteins were assessed. The whole genomes of these 18 strains were sequenced and analyzed for mutations leading to drug resistance. The results revealed that ertapenem resistance may be related to ramR mutation. The function of ramR was confirmed using gene complementation to the original strain to determine the mechanism underlying ertapenem resistance of K. pneumoniae strains. In total, 7.4% of the tested CRKP strains were resistant only to ertapenem. None of these strains contained carbapenemase genes. Of the 18 ertapenem-resistant strains, 17 expressed the efflux pump, and outer membrane protein expression was reduced or absent in 4 strains. Whole-genome sequencing revealed the presence of mutations that introduced premature ramR codons stop in 14 strains (77.78%). When a functional copy of ramR was restored in the 14 strains, the minimum inhibitory concentration of ertapenem decreased, inhibition of efflux pumps was not detected, and the expression of outer membrane protein OmpK35 was either increased or was restored. These findings reveal the existence of ertapenem-resistant K. pneumoniae exhibiting no clonal transmission between strains. Mutations in ramR were demonstrated to cause efflux pump inhibition and over-expression of outer membrane protein OmpK35 in some strains, which is implicated in ertapenem resistance only in K. pneumoniae.

Vehicle object detection is one of the important research directions in the field of computer vision. Aiming at solving the problems of low accuracy, slow speed, and unsatisfactory results of using traditional methods to detect the object of the vehicle in front of the driverless car on the road, this paper proposes an improved YOLOv3 vehicle target detection algorithm which we name it F-YOLOv3. First the multi-scale prediction network model is improved according to actual traffic conditions and efficiency requirements based on the original general object detection YOLOv3 algorithm. Then a scale prediction layer is added to improve the detection accuracy of large vehicles and improved k-means++ the algorithm is used to improve the effect of anchor box dimensional clustering and the detection speed. At last an experiment was conducted on a self-made dataset and compared with YOLOv3 in order to test the effectiveness of the F-YOLOv3 algorithm. The test results show that the improved F-YOLOv3 model has a precision mAP of 91.12% and a speed of 59FPS, which are better than the traditional general object detection YOLOv3 algorithm. Therefore, the algorithm has better performance and popularization prospect in vehicle object detection.

Underwater wireless optical communication is facing absorption, scattering problems, which, in principle, can be greatly resolved by underwater photon-counting communication (UPCC) technology that exhibits high-sensitivity communication characteristics in long-range underwater wireless optical communication. Recent studies on UPCC are mainly focused on a single intensity modulation such as on–off keying (OOK) and pulse position modulation (PPM) technologies, and the comprehensive analysis of communication performance combing OOK modulation and digital pulse modulations remains a lack. To this, by using a UPCC system based on a single-photon avalanche diode, we reveal the communication performances of OOK, PPM, differential pulse interval modulation (DPIM), differential pulse position modulation (DPPM), and dual-header pulse interval modulation, and find that (1) the PPM has the longest transmission distance at the same bit error ratio when M > 2, but the lowest communication rate under identical modulation bandwidth and average transmit power; and (2) the DPPM and DPIM perform the optimum communication performance at the fixed communication rate when M = 8. We thus conclude that the DPPM and DPIM have advantages of low modulation bandwidth and long time slot time compared with PPM, indicating the significance of reducing the difficulty of signal synchronization and the complexity of the underwater photon-counting system accordingly.