Antibiotic-resistant bacteria are a serious threat to human and animal health. Metabolite-enabled eradication of drugresistant pathogens is an attractive strategy, and metabolite adjuvants, such as fumarate, are used for restoring the bactericidal ability of antibiotics. However, we show that metabolites in the TCA cycle increase the viability of Edwardsiella tarda against chloramphenicol (CAP), based on the survival assay of differential metabolites identified by LC-MS/MS. Furthermore, NADPH promotes CAP resistance in the CAP-resistant strain, while oxidants restore the bactericidal ability. Finally, we show that the intracellular redox state determines the sensitivity to CAP, and the total antioxidative capacity is decreased significantly in the antibiotic-resistant strain. Considering that the metabolites promote CAP resistance, metabolite adjuvants should be applied very cautiously. Overall, our research expands on the knowledge that the redox state is related to the bactericidal ability of CAP.

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26A Multi-frequency High Frequency (MHF) Radar system was designed and 27 developed by Wuhan University in 2007. This system can simultaneously operate at 28 four frequencies at most in the band of 7.5-25 MHz. This paper focuses on discussing 29 the performances of MHF radar system deployed along the coast of the East China 30 Sea based on comparisons with multi-depth ADCP data sets, which were obtained 31 from ADCPs deployed at different locations in August 2010 during a small storm. The 32 comparisons illustrate that radar-derived radial currents are correlated with ADCP 33 data at 2-4 m depth most, with correlation coefficients over 0.95 and RMS differences 34 less than 0.12 m/s for both operating frequencies. Bearing offsets at A, C and D points 35 are computed for different operating frequencies, with magnitudes of 0-11 degrees.36The capability of MHF radar to measure currents at different depths is explored. 37The results indicate that effective depth of current measurements by MHF radar 38 increases with decreasing operating frequency. A linear regression (with a regression 39 coefficient of 0.0576) of the responses in the mean effective depth on the predictors in 40 radio wavelength is obtained. The dominant semidiurnal and diurnal constituents are 41 also analyzed. The radial current amplitudes of M2 and K1 constituent are strong in 42 this area during this experiment. The residual currents vary with wind speed, with a 43 correlation coefficient of 0.52. We also yield a correlation coefficient of 0.79 between 44 non-tidal currents and the radial wind speed after clockwise rotating the wind vector 45 by about 50 degrees. 46 376 Barrick, D. E., 1972: First-Order Theory and Analysis of MF/HF/VHF Scatter from 377 the Sea. IEEE Trans. Antennas Propag., AP-20, 2-10.

Wind sea and swell representing different weather conditions generally coexist in both open waters and coastal areas, which results in bimodal or multipeaked features in directional wave spectrum. Because they make wave parameters such as significant wave height and mean wave period of the mixed sea state less meaningful, the processes of separation and identification of wind sea and swell are crucial. Consistent wind sea and swell results can be obtained by a commonly used method based on wave age (WA) with the directional wave spectrum and wind velocity. However, the subjective dependence of wave age threshold selection and the required wind information restrict the application of this method. In this study, a practical method based on the overshoot phenomenon (OP) in wind-generated waves is proposed to extract wind sea and swell from the directional wave spectrum without any other meteorology information. Directional wave spectra derived from an S-band Doppler radar deployed on the coast of the South China Sea have been utilized as the datasets to investigate the performance of both methods. The proposed OP method is then validated by comparing it with the WA method and the verifying results are presented.

One pivotal factor affecting the accuracy of HF radar current measurements is the direction of arrival (DOA) estimation performance of the current signal. The beamforming technology or superresolution algorithm cannot always perform best in practical applications because of the phase errors existing in array channels. These phase errors, which cause uncertain estimation of DOA, lead to confused values in radial current maps. To solve this problem, this paper is focused on discussing the performances of two autocalibration methods using sea echoes for multifrequency high-frequency (MHF) radar current measurements. These two array calibration methods, based on maximum likelihood (ML) and multiple signal classification (MU), first seek single-DOA sea echoes and then gather them for array calibration using different cost functions. The ML and MU methods provide approximate mean phases, while the standard phase errors of the MU method are smaller. After array calibration using these two methods, the results show significant improvements in current retrievals. Comparisons between the MHF radar and ADCPs reveal that array calibration using the ML and MU methods also improves the estimation of radial currents clearly, with correlation coefficients over 0.93 and rms differences of 0.09-0.18 m s 21 at different operating frequencies and sampling locations. The performance of the bearing offset is also improved. Only small bearing offsets less than 108 exist in radial current measurements. Therefore, this paper demonstrates that array calibration is a crucial part for current measurements, especially for direction-finding HF radar.