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This paper reports a new technique that combines the features of Accumulative Roll Bonding (ARB) and Asymmetric Rolling (AR). This technique has been developed to enable production of ultra-thin bimetallic foils. Initially, 1.5 mm thick AA1050 and AA6061 foils were roll-bonded using ARB at 200°C, with 50% reduction. The resulting 1.5 mm bimetallic foil was subsequently thinned to 0.04 mm through four AR passes at room temperature. The speed ratio between the upper and lower AR rolls was 1:1.3. The tensile strength of the bimetallic foil was seen to increase with reduction in thickness. The ductility of the foil was seen to reduce upon decreasing the foil thickness from 1.5 mm to 0.14 mm, but increase upon further reduction in thickness from 0.14 mm to 0.04 mm. The grain size was about 140 nm for the AA6061 layer and 235 nm for the AA1050 layer, after the third AR pass.

Sophora tonkinensis belongs to genus Sophora of the fabaceae family. it is mainly distributed in the ridge and peak regions of limestone areas in western china and has high medicinal value and important ecological functions. Wild populations of S. tonkinensis are in danger and need urgent conservation. furthermore, wild S. tonkinensis resources are very limited relative to the needs of the market, and many adulterants are present on the market. therefore, a method for authenticating S. tonkinensis and its adulterants at the molecular level is needed. chloroplast genomes are valuable sources of genetic markers for phylogenetic analyses, genetic diversity evaluation, and plant molecular identification. In this study, we report the complete chloroplast genome of S. tonkinensis. The circular complete chloroplast genome was 154,644 bp in length, containing an 85,810 bp long single-copy (LSC) region, an 18,321 bp short single-copy (SSC) region and two inverted repeat (IR) regions of 50,513 bp. The S. tonkinensis chloroplast genome comprised 129 genes, including 83 protein-coding genes, 38 transfer RNA (tRNA) genes, and 8 ribosomal RNA (rRNA) genes. The structure, gene order and guanine and cytosine (Gc) content of the S. tonkinensis chloroplast genome were similar to those of the Sophora alopecuroides and Sophora flavescens chloroplast genomes. A total of 1,760 simple sequence repeats (SSRs) were identified in the chloroplast genome of S. tonkinensis, and most of them (93.1%) were mononucleotides. Moreover, the identified SSRs were mainly distributed in the LSC region, accounting for 60% of the total number of SSRs, while 316 (18%) and 383 (22%) were located in the SSC and IR regions, respectively. Only one complete copy of the rpl2 gene was present at the LSc/iRB boundary, while another copy was absent from the iRA region because of the incomplete structure caused by iR region expansion and contraction. the phylogenetic analysis placed S. tonkinensis in papilionoideae, sister to S. flavescens, and the genera Sophora and Ammopiptanthus were closely related. the complete genome sequencing and chloroplast genome comparative analysis of S. tonkinensis and its closely related species presented in this paper will help formulate effective conservation and management strategies as well as molecular identification approaches for this important medicinal plant.

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Background Histone acetylation is an important epigenetic modification that regulates gene activity in response to stress. Histone acetylation levels are reversibly regulated by histone acetyltransferases ( HATs ) and histone deacetylases ( HDACs ). The imperative roles of HDACs in gene transcription, transcriptional regulation, growth and responses to stressful environment have been widely investigated in Arabidopsis . However, data regarding HDACs in kenaf crop has not been disclosed yet. Results In this study, six HDACs genes ( HcHDA2 , HcHDA6 , HcHDA8 , HcHDA9 , HcHDA19 , and HcSRT2 ) were isolated and characterized. Phylogenetic tree revealed that these HcHDACs shared high degree of sequence homology with those of Gossypium arboreum . Subcellular localization analysis showed that GFP-tagged HcHDA2 and HcHDA8 were predominantly localized in the nucleus, HcHDA6 and HcHDA19 in nucleus and cytosol. The HcHDA9 was found in both nucleus and plasma membranes. Real-time quantitative PCR showed that the six HcHDACs genes were expressed with distinct expression patterns across plant tissues. Furthermore, we determined differential accumulation of HcHDACs transcripts under salt and drought treatments, indicating that these enzymes may participate in the biological process under stress in kenaf. Finally, we showed that the levels of histone H3 and H4 acetylation were modulated by salt and drought stress in kenaf. Conclusions We have isolated and characterized six HDACs genes from kenaf. These data showed that HDACs are imperative players for growth and development as well abiotic stress responses in kenaf. Electronic supplementary material The online version of this article (10.1186/s40659-019-0227-6) contains supplementary material, which is available to authorized users.