Experimental investigation on characteristics of graphene acoustic transducers driven by electrostatic and electromagnetic forces.

Acoustic transducers with graphene film have high sensitivity and wide bandwidth of frequency response as receivers. However, they exist in transmitting mode with low radiation performance. We propose an effective approach to enhance radiation performance of the graphene acoustic transducer by embedding a coil in insulating layer, and investigate the characteristics of graphene acoustic transducers by experiments. A graphene acoustic transducer is designed and fabricated. The highest receiving sensitivity of the transducer is -30 dB. The output sound pressure level of the transducer is more than 3 dB on average in the range of 2 âˆ¼ 16 kHz compared without a coil. And the sound pressure level increases by 6 dB on average in the range of 40 âˆ¼ 45 kHz. These results demonstrate that the graphene transducer maintains high receiving performance, and also improves acoustic radiation performance, which greatly expands its application field.

Genome-wide identification and expression analysis of the NCED family in cotton (Gossypium hirsutum L.).

Abscisic acid (ABA) is an important plant hormone that plays multiple roles in regulating growth and development as well as in stress responses in plants. The NCED gene family includes key genes involved in the process of ABA synthesis. This gene family has been found in many species; however, the function of the NCED gene family in cotton is unclear. Here, a total of 23 NCED genes (designated as GhNCED1 to GhNCED23) were identified in cotton. Phylogenetic analysis indicated that the identified NCED proteins from cotton and Arabidopsis could be classified into 4 subgroups. Conserved motif analysis revealed that the gene structure and motif distribution of proteins within each subgroup were highly conserved. qRT-PCR and ABA content analyses indicated that NCED genes exhibited stage-specific expression patterns at tissue development stages. GhNCED5, GhNCED6 and GhNCED13 expression was similar to the change in ABA content, suggesting that this gene family plays a role in ABA synthesis. These results provide a better understanding of the potential functions of GhNCED genes.

Genome-wide identification of differentially expressed miRNAs induced by ethephon treatment in abscission layer cells of cotton (Gossypium hirsutum).

Cotton is one of the most important economic crops and its production is influenced by various adverse factors. Boll shedding at an inappropriate period causes the severe loss of cotton yield. Ethephon can promote the formation of abscission layer cells, resulting in boll shedding. To genome-widely investigate the differentially expressed miRNAs involved in the formation of abscission layer cells, two sRNA libraries were constructed using abscission tissues of cotton pedicels treated with ethephon or water. A total of 55,264,755 and 59,069,866 clean reads were generated in two libraries. 460 mature miRNAs were identified, including 301 known miRNAs and 159 novel miRNAs. Among them, one known gra-MIR530b and seven novel miRNAs (gar-novel-miR88-3p/gra-novel-miR8-3p, gar-novel-miR16-5p, gar-novel-miR100-3p, gar-novel-miR75-3p/gra-novel-miR92-3p,gar-novel-miR32-5p/gra-novel-miR30-5p, gar-novel-miR9-5p and gra-novel-miR61-3p) were expressed differentially in abscission tissues. Seven-two genes were predicted as potential targets of the eight miRNAs. Gene ontology (GO) analyses revealed that most of these target genes are auxin response factors (ARFs), GTPase activators, and the regulators of oxidative phosphorylation and photosynthesis. Hence, we speculate that these miRNAs might regulate cell separation and aging to affect the formation of bscission layer cells. Our findings will provide a new insight into the regulatory mechanism of miRNAs involved in boll shedding.

Frequency Representation: Visualization and Clustering of Acoustic Data Using Self-Organizing Maps.

Extraction and display of frequency information in three-dimensional (3D) acoustic data are important steps to analyze object characteristics, because the characteristics, such as profiles, sizes, surface structures, and material properties, may show frequency dependence. In this study, frequency representation (FR) based on phase information in multispectral acoustic imaging (MSAI) is proposed to overcome the limit of intensity or amplitude information in image display. Experiments are performed on 3D acoustic data collected from a rigid surface engraved with five different letters. The results show that the proposed FR technique can not only identify the depth of the five letters by the colors representing frequency characteristics but also demonstrate the 3D image of the five letters, providing more detailed characteristics that are unavailable by conventional acoustic imaging.