Delay estimation for cortical-muscular interaction with wavelet coherence time lag.

BACKGROUND: Cortico-muscular coherence (CMC) between the cerebral cortex and muscle activity is an effective tool for studying neural communication in the motor control system. To accurately evaluate the coherence between electroencephalogram (EEG) and electromyogram (EMG) signals, it is necessary to accurately calculate the time delay between physiological signals to ensure signal synchronization. NEW METHOD: We proposed a new delay estimation method, named wavelet coherence time lag (WCTL) and the significant increase areas (SIA) index as a measure of the specific region enhancement effect of the magnitude squared coherence (MSC) image. RESULTS: The grip strength level had a small effect on the information transmission time from the cortex to the muscles, while the transmission time from the cortex to different muscle channels was different for the same task. A positive correlation was found between the grip strength level and the SIA index on the ß band of C3-B and the α and ß bands of C3-FDS. COMPARISON WITH EXISTING METHOD: The WCTL method was found to accurately calculate the delay time even when the number of repeated segments was low in a simple motor control model, and the results were more accurate than the rate of voxels change (RVC) and CMC with time lag (CMCTL) methods. CONCLUSIONS: The WCTL is an effective method for detecting the transmission time of information between the cortex and muscles, laying the foundation for future rehabilitation treatment for stroke patients.

A new class of nucleating agents for poly(L-lactic acid): Environmentally-friendly metal salts with biomass-derived ligands and advanced nucleation ability.

Adding nucleating agents has been a successful strategy to boost the heat resistance of poly(L-lactic acid) (PLLA) by increasing the crystallinity. In this study, a new series of bio-based complexes as nucleating agents for PLLA, including twelve combinations of three eco-friendly metal ions (Zn, Mg, Ca) and four biomass-derived α-hydroxy acids, were successfully synthesized to respectively investigate the effects of metal ions as well as ligands on nucleation capacity of complexes. By investigating the non-isothermal and isothermal crystallization at 135 °C of PLLA with 0.3 wt% loading of complexes, both zinc and magnesium salts of L-mandelic acid showed excellent nucleation capacities. And magnesium L-mandelate performed better, raising the crystallinity of PLLA to 44.4 % as well as minimizing its crystallization half-time from 73 min to 2.7 min. The growth and denser distribution of PLLA spherulites on the salt surface were also observed by POM, reflecting epitaxial nucleation as the possible mechanism. A novel inspiration, utilizing VESTA software to simulate the crystal structure of zinc L-mandelate (Zn(L-MA)2), was proposed to determine the nucleation mechanism. Also, using polyethylene terephthalate (PET) as a test protocol, the rationality of the model could be approved by checking the fitness of nucleating prediction and experiment results.

Reassessment of the Phylogeny and Systematics of Chinese Parnassia (Celastraceae): A Thorough Investigation Using Whole Plastomes and Nuclear Ribosomal DNA.

Parnassia L., a perennial herbaceous genus in the family Celastraceae, consists of about 60 species and is mainly distributed in the Pan-Himalayan and surrounding mountainous regions. The taxonomic position and phylogenetic relationships of the genus are still controversial. Herein, we reassessed the taxonomic status of Parnassia and its intra- and inter-generic phylogeny within Celastraceae. To that end, we sequenced and assembled the whole plastid genomes and nuclear ribosomal DNA (nrDNA) of 48 species (74 individuals), including 25 species of Parnassia and 23 species from other genera of Celastraceae. We integrated high throughput sequence data with advanced statistical toolkits and performed the analyses. Our results supported the Angiosperm Phylogeny Group IV (APG IV) taxonomy which kept the genus to the family Celastraceae. Although there were topological conflicts between plastid and nrDNA phylogenetic trees, Parnassia was fully supported as a monophyletic group in all cases. We presented a first attempt to estimate the divergence of Parnassia, and molecular clock analysis indicated that the diversification occurred during the Eocene. The molecular phylogenetic results confirmed numerous taxonomic revisions, revealing that the morphological characters used in Parnassia taxonomy and systematics might have evolved multiple times. In addition, we speculated that hybridization/introgression might exist during genus evolution, which needs to be further studied. Similarly, more in-depth studies will clarify the diversification of characters and species evolution models of this genus.

Plastome sequencing reveals phylogenetic relationships among Comastoma and related taxa (Gentianaceae) from the Qinghai-Tibetan Plateau.

Genus Comastoma (subt. Swertiinae, Gentianaceae) contains species, such as "Zangyinchen," that are important herbs in Tibetan medicine. The phylogenetic relationship of this within Gentianaceae and the circumscriptions of its species have long been controversial with conflicting morphological and molecular data reported. Here, we used whole chloroplast genome sequences for Comastoma species and related taxa to reconstruct their phylogeny and clarify their taxonomic relationships. The results revealed that the length of all plastome sequenced varied from 149 to 151 kb and have high similarity in structure and gene content. Phylogenomic analysis showed that Comastoma is a monophyletic group, closely related to the genus Lomatogonium. The divergence time estimation showed that Gentianaceae diverged at about 21.81 Ma, while the split of Comastoma occurred at 7.70 Ma. However, the results suggested the crown age of species formation in this genus is after 4.19 Ma. Our results suggest that QTP uplift, the alternation of Quaternary glaciation and interglaciation, and monsoon changes might have acted as drivers of speciation in Comastoma.

Energy-Transfer-Mediated Photocatalysis by a Bioinspired Organic Perylenephotosensitizer HiBRCP.

Energy transfer plays a special role in photocatalysis by utilizing the potential energy of the excited state through indirect excitation, in which a photosensitizer determines the thermodynamic feasibility of the reaction. Bioinspired by the energy-transfer ability of natural product cercosporin, here we developed a green and highly efficient organic photosensitizer HiBRCP (hexaisobutyryl reduced cercosporin) through structural modification of cercosporin. After structural manipulation, its triplet energy was greatly improved, and then, it could markedly promote the efficient geometrical isomerization of alkenes from the E-isomer to the Z-isomer. Moreover, it was also effective for energy-transfer-mediated organometallic catalysis, which allowed realization of the cross-coupling of aryl bromides and carboxylic acids through efficient energy transfer from HiBRCP to nickel complexes. Thus, the study on the relationship between structural manipulation and their photophysical properties provided guidance for further modification of cercosporin, which could be applied to more meaningful and challenging energy-transfer reactions.

Complete chloroplast genome sequence of Adenostemma lavenia (Asteraceae) and phylogenetic analysis with related species.

Adenostemma lavenia is a perennial medical herb in the family Asteraceae. Here, we sequenced and analyzed the complete chloroplast genome of A. lavenia. The complete chloroplast genome size is 150,063 bp with a GC content of 37.63%. The A. lavenia chloroplast genome is a typical quadripartite structure, including a large single-copy region (LSC) of 82,017 bp and a small single-copy region (SSC) of 18,142 bp separated by a pair of inverted repeats (IRs) of 24,952 bp each. A total of 114 unique genes, including 29 tRNA genes, four rRNA genes, and 81 protein-coding genes were found in the chloroplast genome. Phylogenetic analysis revealed that A. lavenia is more closely related with Chromolaena odorata.

The complete chloroplast genome sequence of Neopallasia pectinata (Asteraceae).

The complete chloroplast (cp) genome of Neopallasia pectinata was sequenced and analyzed in this study. It was 150,766 bp in length and has a typical circular structure, including a large single copy (LSC) with 82,605 bp, two inverted repeats (IRs) with 24,944 bp, and a small single copy (SSC) with 18,273 bp. The phylogenetic analysis of N. pectinata and its related taxa was conducted depended on the complete cp-genome sequences. The maximum likelihood tree indicates a close relationship between Chrysanthemum and Neopallasia. The cp-genome of N. pectinata is useful for future phylogenetic studies of Asteraceae.

Recurrent hybridization underlies the evolution of novelty in Gentiana (Gentianaceae) in the Qinghai-Tibetan Plateau.

The Qinghai-Tibetan Plateau (QTP) and adjacent areas are centres of diversity for several alpine groups. Although it is known that the QTP acted as a source area for diversification of the alpine genus Gentiana, the evolutionary processes underlying diversity in this genus, especially the formation of narrow endemics, are still poorly understood. Hybridization has been proposed as a driver of plant endemism in the QTP but few cases have been documented with genetic data. Here, we describe a new endemic species in Gentiana section Cruciata as G. hoae sp. nov., and explore its evolutionary history with complete plastid genomes and nuclear ribosomal internal transcribed spacer sequence data. Genetic divergence within G. hoae ~3 million years ago was followed by postglacial expansion on the QTP, suggesting Pleistocene glaciations as a key factor shaping the population history of G. hoae. Furthermore, a mismatch between plastid and nuclear data suggest that G. hoae participated in historical hybridization, while population sequencing show this species continues to hybridize with the co-occurring congener G. straminea in three locations. Our results indicate that hybridization may be a common process in the evolution of Gentiana and may be widespread among recently diverged taxa of the QTP.

The complete chloroplast genome of Triosteum himalayanum (Caprifoliaceae), a perennial alpine herb.

Triosteum himalayanum is a perennial herb which is distributed in the eastern Himalayas, Hengduan Mountains, and central China. The complete chloroplast genome of T. himalayanum is studied for the first time, which is 154,579 bp in length and is divided into four regions: two inverted repeat (IRA and IRB) regions of 23,370 bp, a small single copy (SSC) region of 18,682 bp and a large single copy (LSC) region of 89,157 bp. The plastid genome contains 133 genes, including 86 protein-coding genes, 39 tRNA genes, and 8 rRNA genes. The overall CG content in the chloroplast genome of T. himalayanum is 38.38%. The phylogenetic analysis on the complete plastome sequence of T. himalayanum will help to show the intergeneric diversity of Caprifoliaceae.

Characterization of the complete chloroplast genome of Linnaea borealis, a rare, clonal self-incompatible plant.

Linnaea borealis L. is a creeping shrub which grows about 5-10 cm high and is a rare clonal plant. Linnaea is a monotypic genus. Here, we release and detail the complete chloroplast genome sequences of L. borealis, whose size is 161,576 bp, containing a large single copy region (LSC) of 85,609 bp and a single copy region (SSC) of 46,694 bp which typically separates by a pair of inverted repeats (IRs) of 29,210 bp. The amount of the overall genes is 136, which includes 37 tRNA genes, eight rRNA genes, and 91 protein-coding genes. The content of the G/C in whole plastome is 61.74% while the G/C content of the LSC, SSC, and IR region are 36.58%, 38.86%, and 42.25%, respectively. The complete cp genome sequences of L. borealis will be a useful resource to the phylogenetics study in family Caprifoliaceae.

Deep Intraspecific Divergence in the Endemic Herb Lancea tibetica (Mazaceae) Distributed Over the Qinghai-Tibetan Plateau.

Qinghai-Tibetan Plateau (QTP) is an important biodiversity hub, which is very sensitive to climate change. Here in this study, we investigated genetic diversity and past population dynamics of Lancea tibetica (Mazaceae), an endemic herb to QTP and adjacent highlands. We sequenced chloroplast and nuclear ribosomal DNA fragments for 429 individuals, collected from 29 localities, covering their major distribution range at the QTP. A total of 19 chloroplast haplotypes and 13 nuclear genotypes in two well-differentiated lineages, corresponding to populations into two groups isolated by Tanggula and Bayangela Mountains. Meanwhile, significant phylogeographical structure was detected among sampling range of L. tibetica, and 61.50% of genetic variations was partitioned between groups. Gene flow across the whole region appears to be restricted by high mountains, suggesting a significant role of geography in the genetic differences between the two groups. Divergence time between the two lineages dated to 8.63 million years ago, which corresponded to the uplifting of QTP during the late Miocene and Pliocene. Ecological differences were found between both the lineages represent species-specific characteristics, sufficient to keep the lineages separated to a high degree. The simulated distribution from the last interglacial period to the current period showed that the distribution of L. tibetica experienced shrinkage and expansion. Climate changes during the Pleistocene glacial-interglacial cycles had a dramatic effect on L. tibetica distribution ranges. Multiple refugia of L. tibetica might have remained during the species history, to south of the Tanggula and north of Bayangela Mountains, both appeared as topological barrier and contributed to restricting gene flow between the two lineages. Together, geographic isolation and climatic factors have played a fundamental role in promoting diversification and evolution of L. tibetica.

Complete chloroplast genome sequence of Parnassia brevistyla (Celastraceae) and phylogenetic analysis with related species.

The taxonomic status of Parnassia has been widely discussed, which has been placed in more than five families, Parnassiaceae, Droseraceae, Saxifragaceae, and Celastraceae. Due to the lack of reliable genetic data, we sequenced and analyzed P. brevistyla chloroplast genome for future genetic study. The complete chloroplast genomes of Parnassia brevistyla was sequenced with NovaSeq 6000. The full length of P. brevistyla chloroplast genomes is 151,728 bp. A total of 114 unique genes, including 30 tRNA genes, four rRNA genes, and 80 protein-coding genes were found in the chloroplast genome. Using the whole chloroplast genome sequences alignment of 10 species from Celastraceae and Saxifragaceae, the phylogenetic relationship was built. The phylogenetic position of P. brevistyla was closely clustered with Celastraceae. The complete chloroplast genome of P. brevistyla provides utility information for further research of phylogenetic relationship and taxonomic status of Parnassia.