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Objective: Necrotizing enterocolitis (NEC) is the leading cause of death among premature infants, and there is a lack of specific early diagnostic markers. Blood sampling is expected to better reflect pathophysiological and metabolic changes in systematic illness, but there is a risk of iatrogenic anemia, especially in premature infants. Dried blood spots technique seems to have important advantages compared to whole blood sampling as it requires only 12–15 μL as sample volume. This study aimed to investigate the special metabolomics of preterm neonates at high risk of NEC using dried blood spots. Methods: Cases and controls were strictly matched 1:1. Dried blood spots (n = 32, 16 cases–16 controls) from newborn screening were subjected to LC–MS/MS. Metabolomic data were analyzed by orthogonal partial least squares-discriminant analysis (OPLS-DA) and univariate/multivariate statistical analysis. Results: Compared to the control group, the NEC group had a significant reduction in seven amino acids (glycine, alanine, threonine, proline, ornithine, lysine, and asparagine). Conclusions: The metabolic profile of neonates with NEC differs significantly from that of controls, making possible their separation with the use of targeted (LC–MS/MS) dried blood spots-based metabolomic analysis. Seven specific markers were identified for early detection and intervention. [ABSTRACT FROM AUTHOR]

Novel 4″- O -(trans- β -arylacrylamido)carbamoyl azithromycin analogs were designed, synthesized and evaluated for their antibacterial activity against nine significant pathogens using broth microdilution method. A majority of these derivatives maintained the activity of azithromycin against susceptible Streptococcus pyogenes and all the compounds demonstrated remarkably improved activity compared with the references against all the three phenotypes of resistant Streptococcus pneumoniae . In particular, compound 24 exhibited the most potent activity against susceptible Staphylococcus aureus (MIC = 0.5 μg/mL), S. pneumoniae (MIC = 0.06 μg/mL) and S. pyogenes (MIC = 0.25 μg/mL). The most active compound 7 (MIC = 0.015 μg/mL) against resistant S. pneumoniae expressing the mef A gene, exhibited 512 and 256-fold more potent activity than erythromycin and azithromycin, respectively. Compounds 28 (MIC = 0.5 μg/mL), 29 (MIC = 0.25 μg/mL) and 30 (MIC = 0.5 μg/mL) demonstrated potent activity against resistant S. pneumoniae expressing the erm B gene, which were 256, 512 and 256-fold better than the references, respectively. [ABSTRACT FROM AUTHOR]

Abstract: To explore a determination method for cyclone vortex tail, the wall pressures at different axial and radial positions of a cylinder-on-cone cyclone were measured and analyzed by the Fast Fourier Transform (FFT) and probability density analyses in this paper. The cyclone vortex tail was also visualized by a red ink tracer. The results show that the cyclone wall pressure does not change in the cylindrical section and gradually decreases in the conical section. The magnitudes of wall pressure at different azimuths are almost identical, indicating an axisymmetrical wall pressure radial profile in these parts of the cyclone. Whereas in the lower part of the cone and/or the upper part of dipleg, there is a sudden fall of wall pressure and non-axisymmetrical pressure radial profile. The minimum wall pressure occurs at about 270° azimuth in this region. Underneath in the next part of the dipleg, the wall pressure rapidly rises and returns to axisymmetry. These characteristics indicate that the vortex tail is bended to wall, turns around in this region, and can be used as evidences of the vortex tail. The position determined by the pressure measurement is close to the position of the rotating ring observed in the tracing experiment. It is also found that the frequency of the inner vortex is different from that of the outer vortex. The inner vortex flow fluctuates stronger and faster than its outer partner. At the vortex tail zone, the vortex breaks and the inner vortex fluctuation is involved in the wall pressure signal. Therefore, the position and dynamic property of the vortex tail can be well identified from the wall pressure measurement. The pressure measurement could provide some solid experimental basis for assessing relations of natural vortex length. [Copyright &y& Elsevier]

Three novel structural series of 4″- O -(1-aralkyl-1,2,3-triazol-4-methyl-carbamoyl) azithromycin analogs were designed, synthesized and evaluated for their in vitro antibacterial activity. All the target compounds exhibited excellent activity against erythromycin-susceptible Streptococcus pyogenes , and significantly improved activity against three phenotypes of erythromycin-resistant Streptococcus pneumoniae compared with clarithromycin and azithromycin. Among the three series of azithromycin analogs, the novel series of 11,4″-disubstituted azithromycin analogs 9a – k exhibited the most effective and balanced activity against susceptible and resistant bacteria. Among them, compound 9j showed the most potent activity against Staphylococcus aureus ATCC25923 (0.008 µg/mL) and Streptococcus pyogenes R2 (1 µg/mL). Besides, all the 11,4″-disubstituted azithromycin analogs 9a – k except 9f shared the identical activity with the MIC value <0.002 µg/mL against Streptococcus pyogenes S2. Furthermore, compounds 9g , 9h , 9j and 9k displayed significantly improved activity compared with the references against all the three phenotypes of resistant S. pneumoniae . Particularly, compound 9k was the most effective (0.06, 0.03 and 0.125 µg/mL) against all the erythromycin-resistant S. pneumoniae expressing the erm gene, the mef gene and the erm and mef genes, exhibiting 2133, 133 and 2048-fold more potent activity than azithromycin, respectively. [ABSTRACT FROM AUTHOR]