Initial respiratory support modality and outcome in preterm infants with less than 32 weeks of gestation in China: A multicentre retrospective cohort study.

BACKGROUND: For initial respiratory management, continuous positive airway pressure (CPAP) is increasingly used for preterm infants, especially for gestational age less than 32 weeks. However, neonatologists are concerned about the potential risks of CPAP support failure. OBJECTIVES: To examine the association between different initial respiratory support modalities and the outcomes of preterm infants at <32 weeks of gestation across multiple neonatal intensive care units (NICU) in China. METHODS: This study was carried out over a period of 12 months in 2018. Unadjusted relative risks (RR) for demographic and clinical characteristics were calculated for CPAP failure and CPAP success in the total cohort using log-linear model based on generalised estimating equations for clustered observations. RESULTS: Among 1560 preterm infants delivered at <32 weeks, the incidence of CPAP failure was 10.3%. After adjustment for demographic and clinical factors, the relative risk of mortality (RR 7.54, 95% CI 5.56, 10.44), pneumothorax (RR 9.85, 95% CI 2.89, 61.53), pulmonary haemorrhage (RR 7.78, 95% CI 4.51, 14.64) and BPD (RR 3.65, 95% CI 3.65, 4.51) were considerably higher for infants in the CPAP failure group than those in the CPAP-S group. However, the risk of poor outcomes in CPAP failure infants was similar to that of those in the initial mechanical ventilation (MV) group. CONCLUSIONS: Continuous positive airway pressure failure was associated with an increased risk of mortality and major morbidities, including BPD, pulmonary haemorrhage and pneumothorax, and was comparable to the risk associated with initial MV.

Clustering of Bacterial Growth Dynamics in Response to Growth Media by Dynamic Time Warping.

Bacterial growth curves, representing population dynamics, are still poorly understood. The growth curves are commonly analyzed by model-based theoretical fitting, which is limited to typical S-shape fittings and does not elucidate the dynamics in their entirety. Thus, whether a certain growth condition results in any particular pattern of growth curve remains unclear. To address this question, up-to-date data mining techniques were applied to bacterial growth analysis for the first time. Dynamic time warping (DTW) and derivative DTW (DDTW) were used to compare the similarity among 1015 growth curves of 28 Escherichia coli strains growing in three different media. In the similarity evaluation, agglomerative hierarchical clustering, assessed with four statistic benchmarks, successfully categorized the growth curves into three clusters, roughly corresponding to the three media. Furthermore, a simple benchmark was newly proposed, providing a highly improved accuracy (~99%) in clustering the growth curves corresponding to the growth media. The biologically reasonable categorization of growth curves suggested that DTW and DDTW are applicable for bacterial growth analysis. The bottom-up clustering results indicate that the growth media determine some specific patterns of population dynamics, regardless of genomic variation, and thus have a higher priority of shaping the growth curves than the genomes do.

A decay effect of the growth rate associated with genome reduction in Escherichia coli.

BACKGROUND: Bacterial growth is an important topic in microbiology and of crucial importance to better understand living cells. Bacterial growth dynamics are quantitatively examined using various methods to determine the physical, chemical or biological features of growing populations. Due to methodological differences, the exponential growth rate, which is a parameter that is representative of growth dynamics, should be differentiated. Ignoring such differentiation in the growth analysis might overlook somehow slight but significant changes in cellular features of the growing population. Both experimental and theoretical investigations are required to address these issues. RESULTS: This study experimentally verified the differentiation in growth rates attributed to different methodologies, and demonstrated that the most popular method, optical turbidity, led to the determination of a lower growth rate in comparison to the methods based on colony formation and cellular adenosine triphosphate, due to a decay effect of reading OD600 during a population increase. Accordingly, the logistic model, which is commonly applied to the high-throughput growth data reading the OD600, was revised by introducing a new parameter: the decay rate, to compensate for the lowered estimation in growth rates. An improved goodness of fit in comparison to the original model was acquired due to this revision. Applying the modified logistic model to hundreds of growth data acquired from an assortment of Escherichia coli strains carrying the reduced genomes led to an intriguing finding of a correlation between the decay rate and the genome size. The decay effect seemed to be partially attributed to the decrease in cell size accompanied by a population increase and was medium dependent. CONCLUSIONS: The present study provides not only an improved theoretical tool for the high-throughput studies on bacterial growth dynamics linking with optical turbidity to biological meaning, but also a novel insight of the genome reduction correlated decay effect, which potentially reflects the changing cellular features during population increase. It is valuable for understanding the genome evolution and the fitness increase in microbial life.

Kresoxim-methyl Derivatives: Synthesis and Herbicidal Activities of (Pyridinylphenoxymethylene)phenyl Methoxyiminoacetates.

A series of new kresoxim-methyl derivatives, (pyridinylphenoxymethylene)phenyl methoxyiminoacetates, were synthesized and their structures were confirmed by NMR and high-resolution mass spectrometry (HRMS). Although derived from a fungicide, the bioassays indicated that several new compounds had good herbicidal activities. At 37.5 g a.i./ha, compound 5c showed 100% inhibition against Abutilon theophrasti, Amaranthus retroflexus, and Eclipta prostrata, which was better than mesotrione. Compound 5e had a broad herbicidal spectrum against broadleaf weeds. The present work indicates that 5c and 5e may serve as new candidates for potential herbicides.

Antioxidant flavonoids from the seed of Oroxylum indicum.

Three new flavonoid glycosides (1-3) and nineteen known compounds (4-22) were isolated from the aqueous ethanolic extract of the seed of Oroxylum indicum. The structures of 1-3 were elucidated on the basis of spectroscopic analysis. Antioxidant activities of all the isolated compounds were evaluated using a DPPH and an ORAC assay. Compounds 3, 5-7, 9 and 12 exhibited potent antioxidant activity in the DPPH assay, while compounds 3-15 showed potent antioxidant capacity in the ORAC assay, and seven antioxidant flavonoids (4-6, 8, 9, 11, 12) were detected as the main ingredients in the methanolic extract of seed of O. indicum using an HPLC analysis.