Trottmann, Felix;Franke, Jakob;Ishida, Keishi;Garcia-Altares, Maria;Hertweck, Christian
年/卷/期：2019 / 58 / 1
In microbial interactions bacteria employ diverse molecules with specific functions, such as sensing the environment, communication with other microbes or hosts, and conferring virulence. Insights into the molecular basis of bacterial communication are thus of high relevance for ecology and medicine. Targeted gene activation and in vitro studies revealed that the cell-to-cell signaling molecule and disease mediator IQS (aeruginaldehyde) of the human pathogen Pseudomonas aeruginosa and related bacteria derives from the siderophore pyochelin. Addition of IQS to bacterial cultures (Burkholderia thailandensis) showed that the signaling molecule is captured by a congener of another siderophore family, malleobactin, to form a nitrone conjugate (malleonitrone) that is active against the IQS-producer. This study uncovers complex communication processes with derailed siderophore functions, a novel nitrone bioconjugation, and a new type of antibiotic against Gram-negative bacteria.
来源期刊：Journal of the Chemical Society of Japan(Chemistry and Industrial Chemistry)
年/卷/期：2000 / / N.1
In the reactions of reagents having C-Mg, N—Mg and 0-Mg bonds with substrates having functional groups (NO2, CO, CN), distribution of the normal (addition and condensation) and abnormal (radical) products is correlated with the values of difference between oxidation and reduction potentials of the reactants (LiE=Eax~Er~) which estimate the relative efficiency of single electron transfer (SET). The study is called zlE—approach.Mild reactivity of the N—Mg reagent derived from anilines is profitable for disclosure of factors governing all of the reactions of the reagent to allow all of t,hose to be classified and characterized. It was found that the use of strongly coordinating ligands as additives led to disclosure of the implicit SET in large 1iE reaction, which was also useful for improvement of the yield of the normal products.
会议集名/来源：ICASSP 2019 - 2019 IEEE International Conference on Acoustics, Speech and Signal Processing, Vol.10: Brighton, Great Britain(GB).12-17 May 2019
In contrast to a 1-D short-time analysis of speech, 2-D approaches aim at characterizing the speech signal attributes jointly in time and frequency. In this paper, we focus on the quasi-periodicity of a voiced spectro-temporal patch and quantify it by proposing an aperiodicity measure defined using the underlying frequency modulations in the patch. We further propose a time-frequency aperiodicity map obtained by overlapping and adding the aperiodicity measures across patches. The proposed aperiodicity map is utilized to obtain band-wise aperiodicity parameters, which are essential for high-quality speech synthesis. The aperiodicity in unvoiced patches is addressed by identifying them using the coherence of the patch. In addition, the proposed technique also provides voiced/unvoiced decisions boundaries of a speech signal. The effectiveness of the proposed band-wise aperiodicity parameters and voiced/unvoiced decisions is verified by incorporating them in an existing state-of-the-art vocoder for speech synthesis. Subjective listening tests show that the quality of the reconstructed speech is on par with that of the state-of-the-art WORLD vocoder in terms of mean opinion score, indicating that spectrotemporal approaches are highly promising for speech analysis and synthesis applications.
aperiodicity in 2-D;band-wise aperiodicy parameters;carrier spectrogram;coherence map