Spontaneous helielectric nematic liquid crystals: Electric analog to helimagnets.

Recently, a type of ferroelectric nematic fluid has been discovered in liquid crystals in which the molecular polar nature at molecule level is amplified to macroscopic scales through a ferroelectric packing of rod-shaped molecules. Here, we report on the experimental proof of a polar chiral liquid matter state, dubbed helielectric nematic, stabilized by the local polar ordering coupled to the chiral helicity. This helielectric structure carries the polar vector rotating helically, analogous to the magnetic counterpart of helimagnet. The helielectric state can be retained down to room temperature and demonstrates gigantic dielectric and nonlinear optical responses. This matter state opens a new chapter for developing the diverse polar liquid crystal devices.

Comparative Genomics and Phylogenetic Analysis of the Chloroplast Genomes in Three Medicinal Salvia Species for Bioexploration.

To systematically determine their phylogenetic relationships and develop molecular markers for species discrimination of Salvia bowleyana, S. splendens, and S. officinalis, we sequenced their chloroplast genomes using the Illumina Hiseq 2500 platform. The chloroplast genomes length of S. bowleyana, S. splendens, and S. officinalis were 151,387 bp, 150,604 bp, and 151,163 bp, respectively. The six genes ndhB, rpl2, rpl23, rps7, rps12, and ycf2 were present in the IR regions. The chloroplast genomes of S. bowleyana, S. splendens, and S. officinalis contain 29 tandem repeats; 35, 29, 24 simple-sequence repeats, and 47, 49, 40 interspersed repeats, respectively. The three specific intergenic sequences (IGS) of rps16-trnQ-UUG, trnL-UAA-trnF-GAA, and trnM-CAU-atpE were found to discriminate the 23 Salvia species. A total of 91 intergenic spacer sequences were identified through genetic distance analysis. The two specific IGS regions (trnG-GCC-trnM-CAU and ycf3-trnS-GGA) have the highest K2p value identified in the three studied Salvia species. Furthermore, the phylogenetic tree showed that the 23 Salvia species formed a monophyletic group. Two pairs of genus-specific DNA barcode primers were found. The results will provide a solid foundation to understand the phylogenetic classification of the three Salvia species. Moreover, the specific intergenic regions can provide the probability to discriminate the Salvia species between the phenotype and the distinction of gene fragments.

Gate-Tunable Surface States in Topological Insulator ß-Ag2Te with High Mobility.

Stimulated by novel properties in topological insulators, experimentally realizing quantum phases of matter and employing control over their properties have become a central goal in condensed matter physics. ß-silver telluride (Ag2Te) is predicted to be a new type narrow-gap topological insulator. While enormous efforts have been plunged into the topological nature in silver chalcogenides, sophisticated research on low-dimensional nanostructures remains unexplored. Here, we report the record-high bulk carrier mobility of 298 600 cm2/(V s) in high-quality Ag2Te nanoplates and the coexistence of the surface and bulk state from systematic Shubnikov-de Haas oscillations measurements. By tuning the correlation between the top and bottom surfaces, we can effectively enhance the contribution of the surface to the total conductance up to 87% at 130 V. These results are instrumental to the high-mobility physics study and even suitable to explore exotic topological phenomena in this material system.

Viscoelastic properties of a thioether-based heliconical twist-bend nematogen.

The twist-bend nematic (NTB) phase is one of the new types of nematics found recently, which possesses local nematic order with a heliconical orientational modulation at the nanoscale. Herein, we quantitatively determined, for the first time, the temperature-dependent elastic and viscosity properties in both the nematic (N) and NTB phases using a thioether-linked cyanobiphenyl dimer CBS7SCB exhibiting a broad temperature range of the NTB phase which is stable down to room temperature. In the N phase, the fundamental elastic moduli: splay and bend elastic moduli (K11 and K33, respectively) are found to be in the order of 10-12 N, and the effective rotational viscosity (γ1) is determined to be in the range of 5-200 mPa s. Meanwhile, the NTB phase is found to exhibit a compressive elastic modulus B in the order of several tens of kilopascals, the effective K11 in the order of 10-10-10-8 N, and a considerably large γ1 value of ∼68.7 Pa s right below the N-NTB phase transition. The present study provides insights into the comprehensive viscoelastic properties based on comparison of the obtained experimental data with not only the existing theoretical prediction but also the preceding experimental works.

Plexin-B1 indirectly affects glioma invasiveness and angiogenesis by regulating the RhoA/αvß3 signaling pathway and SRPK1.

Gliomas are one of the most common primary brain tumors in adults. They display aggressive invasiveness, are highly vascular, and have a poor prognosis. Plexin-B1 is involved in numerous cellular processes, especially cellular migration and angiogenesis. However, the role and regulatory mechanisms of Plexin-B1 in gliomas are not understood and were thus investigated in this study. By using multiple and diverse experimental techniques, we investigated cell apoptosis, mitochondrial membrane potential, cell migration and invasion, angiogenesis, PI3K and Akt phosphorylation, and also the levels of SRPK1 and αvß3 in glioma cells and animal glioma tissues. The results indicated that Plexin-B1 expression in glioma cell lines is increased compared to normal human astrocytes. Plexin-B1 mediates RhoA/integrin αvß3 involved in the PI3K/Akt pathway and SRPK1 to influence the growth of glioma cell, angiogenesis, and motility in vitro and in vivo. Thus, Plexin-B1 signaling regulates the Rho/αvß3/PI3K/Akt pathway and SRPK1, which are involved in glioma invasiveness and angiogenesis. Therefore, the new drug research should focus on Plexin-B1 as a target for the treatment of glioma invasion and angiogenesis.

The influence of SRPK1 on glioma apoptosis, metastasis, and angiogenesis through the PI3K/Akt signaling pathway under normoxia.

Gliomas, the most common primary brain tumors, have low survival rates and poorly defined molecular mechanisms to target for treatment. Serine/arginine SR protein kinases 1 (SRPK1) can highly and specifically phosphorylate the SR protein found in many tumors, which can influence cell proliferation and angiogenesis. However, the roles and regulatory mechanisms of SRPK1 in gliomas are not understood. The aim of this study was to determine the functions and regulation of SRPK1 in gliomas. We found that SRPK1 inhibition induces early apoptosis and significantly inhibits xenograft tumor growth. Our results indicate that SRPK1 affects Akt and eIF4E phosphorylation, Bax and Bcl-2 activation, and HIF-1 and VEGF production in glioma cells. Moreover, transfection of SRPK1 siRNA strongly reduced cell invasion and migration by regulating the expression of MMP2 and MMP9 and significantly decreased the volume of tumors and angiogenesis. We show here that a strong link exists among SRPK1, Akt, eIF4E, HIF-1, and VEGF activity that is functionally involved in apoptosis, metastasis, and angiogenesis of gliomas under normoxic conditions. Thus, SRPK1 may be a potential anticancer target to inhibit glioma progression.

Mesenchymal Stem Cell-Induced Neuroprotection in Pediatric Neurological Diseases: Recent Update of Underlying Mechanisms and Clinical Utility.

Pediatric neurological diseases refer to a group of disorders that affect the nervous system in children. These conditions can have a significant impact on a child's development, cognitive function, motor skills, and overall quality of life. Stem cell therapy is a new and innovative approach to treat various neurological conditions by repairing damaged neurons and replacing those that have been lost. Mesenchymal stem cells (MSCs) have gained significant recognition in this regard due to their ability to differentiate into different cell types. MSCs are multipotent self-replicating stem cells known to render promising results in the treatment of stroke and spinal cord injury in adults. When delivered to the foci of damage in the central nervous system, stem cells begin to differentiate into neural cells under the stimulation of paracrine factors and secrete various neurotrophic factors (NTFs) like nerve growth factor (NGF), brain-derived neurotrophic factor (BDNF), and neurotrophin-3 (NT-3) that expedite the repair process in injured neurons. In the present review, we will focus on the therapeutic benefits of the MSC-based therapies in salient pediatric neurological disorders including cerebral palsy, stroke, and autism.

Surface photogalvanic effect in Ag2Te.

The bulk photovoltaic effect (BPVE) in non-centrosymmetric materials has attracted significant attention in recent years due to its potential to surpass the Shockley-Queisser limit. Although these materials are strictly constrained by symmetry, progress has been made in artificially reducing symmetry to stimulate BPVE in wider systems. However, the complexity of these techniques has hindered their practical implementation. In this study, we demonstrate a large intrinsic photocurrent response in centrosymmetric topological insulator Ag2Te, attributed to the surface photogalvanic effect (SPGE), which is induced by symmetry reduction of the surface. Through diverse spatially-resolved measurements on specially designed devices, we directly observe that SPGE in Ag2Te arises from the difference between two opposite photocurrent flows generated from the top and bottom surfaces. Acting as an efficient SPGE material, Ag2Te demonstrates robust performance across a wide spectral range from visible to mid-infrared, making it promising for applications in solar cells and mid-infrared detectors. More importantly, SPGE generated on low-symmetric surfaces can potentially be found in various systems, thereby inspiring a broader range of choices for photovoltaic materials.

Spontaneous periodic polarization wave in helielectric fluids.

By analogy with spin waves in ferromagnetic systems, the polarization (or dipole) wave is the electric counterpart that remains elusive. Here, we discover that the helielectricity, i.e. a polarization field with helicoidal helices that corresponds to a quasi-layered chiral nematic environment, causes a spontaneous formation of large-scale polarization waves in the form of the sinusoidal function. Both experimental and theoretical analyses reveal that the polarization ordering over a threshold polarization strength violates the inherent periodicity of the polarization helices, thus penalizing the compression energy. It drives a second-order structural transition to a periodically modulated polarization wave state. The roles of chirality and confinement condition are discussed.

Different Music Training Modulates Theta Brain Oscillations Associated with Executive Function.

Different music training involves different hand coordination levels and may have a significant influence on brain oscillation for the executive function. However, few research has focused on the plasticity of executive function and the brain oscillation modulated by different musical instrument training modules. In this study, we recruited 18 string musicians, 20 pianists, and 19 non-musicians to perform a bimanual key pressing task during EEG recording. Behavioral results revealed that pianists have the highest accuracy and the shortest response time, followed by string musicians and non-musicians (p < 0.05). Time-frequency analyses of EEG revealed that pianists generated significantly greater theta power than the other groups from 500 ms to 800 ms post-stimulus in mid-central, frontal brain areas, and motor control areas. Functional connectivity analyses found that the pianists showed significantly greater connectivity in the frontal-parietal area in theta band based on phase-locking value analysis, which suggests that piano training improves executive function and enhances the connectivity between prefrontal and mid-central regions. These findings contribute to a better understanding of the effects of different music training on executive function.

Bioinspired Nanocomposites with Self-Adaptive Stress Dispersion for Super-Foldable Electrodes.

In flexible electronics, appropriate inlaid structures for stress dispersion to avoid excessive deformation that can break chemical bonds are lacking, which greatly hinders the fabrication of super-foldable composite materials capable of sustaining numerous times of true-folding. Here, mimicking the microstructures of both cuit cocoon possessing super-flexible property and Mimosa leaf featuring reversible scatheless folding, super-foldable C-web/FeOOH-nanocone (SFCFe) conductive nanocomposites are prepared, which display cone-arrays on fiber structures similar to Mimosa leaf, as well as non-crosslinked junctions, slidable nanofibers, separable layers, and compressible network like cuit cocoon. Remarkably, the SFCFe can undergo over 100 000 times of repeated true-folding without structural damage or electrical conductivity degradation. The mechanism underlying this super-foldable performance is further investigated by real-time scanning electron microscopy folding characterization and finite-element simulations. The results indicate its self-adaptive stress-dispersion mechanism originating from multilevel biomimetic structures. Notably, the SFCFe demonstrates its prospect as a super-foldable anode electrode for aqueous batteries, which shows not only high capacities and satisfactory cycling stability, but also completely coincident cyclic voltammetry and galvanostatic charge-discharge curves throughout the 100 000 times of true-folding. This work reports a mechanical design considering the self-adaptive stress dispersion mechanism, which can realize a scatheless super-foldable electrode for soft-matter electronics.

Photodetection and Infrared Imaging Based on Cd3As2 Epitaxial Vertical Heterostructures.

Due to the nontrivial electronic structure, Cd3As2 is predicted to possess various transport properties and outstanding photoresponses. Photodetectors based on topological materials are mostly made up of nanoplates, yet monolithic in situ heteroepitaxial Cd3As2 photodetectors are rarely reported to date owing to the crystal mismatch between Cd3As2 and semiconductors. Here, we demonstrate Cd3As2/ZnxCd1-xTe/GaSb vertical heteroepitaxial photodetectors via molecule beam epitaxy. By constructing dual-Schottky junctions, these photodetectors show high responsivity and external quantum efficiency in a broadband spectrum. Based on the strong and fast photoresponse, we achieved visible light to near-infrared imaging using a one-pixel imaging system with a galvo. Our results illustrate that the integration of three-dimensional Dirac semimetal Cd3As2 with semiconductors has potential applications in broadband photodetection and infrared cameras.

Characterization and comparative analysis of the plastome sequence from Justicia ventricosa (Lamiales: Acanthaceae).

Justicia ventricosa is a characteristic ethnic herb commonly used to treat Orthopedic pains. Here, to confirm its phylogenetic position and to develop molecular markers that can distinguish different Justicia species, we obtained and analyzed the plastome of Justicia ventricosa. The plastome was sequenced using the Illumina HiSeq sequencing platform, assembled with NOVOPlasty, and annotated with CPGAVAS2. The genome has a circular structure of 149,700 bp, containing a large single-copy region of 82,324 bp, a small single-copy region of 17,260 bp, and two reverse repeat regions of 25,058 bp each. It encodes 112 unique genes, including 76 protein-coding genes, eight ribosomal RNA genes, and 28 transfer RNA genes. Twenty cis-splicing genes were found. In total, we predicted 19 microsatellite repeats and 13 tandem repeat sequences. For distributed repeats, four were palindrome repeats and five were direct repeats. To find the highly variable intergenic spacer (IGS) regions, we calculated the K2P distances for IGS regions from four Justicia species. The K2P values ranged from 6.11 to 57.82. The largest K2P distances were found for ccsA-ndhD, petB-petD, psbK-psbI, and ycf4-cemA. Phylogenetic analysis results showed that J. ventricosa was most closely related to J. leptostachya. To determine how Justicia species adapt to the environment, we performed selection pressure analysis. Nine genes were found to have undergone positive selection. Lastly, we performed a genome-wise DNA barcode prediction, seven pairs of primers were found. The results provide valuable information that can be used for molecular marker development and bioprospecting in Justicia species.

Development of ferroelectric nematic fluids with giant-ε dielectricity and nonlinear optical properties.

Superhigh-ε materials that exhibit exceptionally high dielectric permittivity are recognized as potential candidates for a wide range of next-generation photonic and electronic devices. In general, achieving a high-ε state requires low material symmetry, as most known high-ε materials are symmetry-broken crystals. There are few reports on fluidic high-ε dielectrics. Here, we demonstrate how small molecules with high polarity, enabled by rational molecular design and machine learning analyses, enable the development of superhigh-ε fluid materials (dielectric permittivity, ε > 104) with strong second harmonic generation and macroscopic spontaneous polar ordering. The polar structures are confirmed to be identical for all the synthesized materials. Furthermore, adapting this strategy to high-molecular weight systems allows us to generalize this approach to polar polymeric materials, creating polar soft matters with spontaneous symmetry breaking.

Chinese and Western Musical Training Impacts the Circuit in Auditory and Reward Systems.

Previous studies have provided evidence about the brain plasticity effects of musical training, however, the issue of how expertise in music styles induced by Chinese or Western musical training affects neuroplasticity and reward responses has been less considered, especially for subjects of Chinese origin. In this work, 16 musicians who trained in the Western music style (Western-trained musicians) and 18 musicians who trained in the Chinese music style (Chinese-trained musicians) were recruited as the musician group for the experiment, while 15 non-musicians were recruited as the control group. Using a paradigm that consisted of listening to Chinese and Western music and measurements using functional magnetic resonance imaging (fMRI) technology, we found that Chinese-trained musicians activated the bilateral superior temporal gyrus (STG) when listening to music, while Western-trained musicians activated the left STG. In addition, under the condition of listening to music with Chinese style, Chinese-trained musicians have a stronger functional connection in the circuit of the auditory and reward system than Western-trained musicians. The finding is opposite under the condition of listening to music with Western style. Interestingly, it seems that the circuit of Chinese-trained musicians is partial to the right STG, while Western-trained musicians show the opposite, i.e., a tendency toward the left STG. The influence of different music styles on experienced musicians is reflected by the functional activities and connections between the auditory system and the reward system. This outcome indicates that training in Chinese music style or Western music style affects the strategies of musicians when listening to music. Musical characteristics such as rhythm, melody and cultural attributes play an important role in this process. These findings, which provide evidence for functional neuroplasticity based on musical training, can enrich our insights into the musical brain.

Photoelectrochemical Performance of Quantum dot-Sensitized TiO2 Nanotube Arrays: a Study of Surface Modification by Atomic Layer Deposition Coating.

Although CdS and PbS quantum dot-sensitized TiO2 nanotube arrays (TNTAs/QDs) show photocatalytic activity in the visible-light region, the low internal quantum efficiency and the slow interfacial hole transfer rate limit their applications. This work modified the surface of the TNTAs/QDs photoelectrodes with metal-oxide overlayers by atomic layer deposition (ALD), such as coating Al2O3, TiO2, and ZnO. The ALD deposition of all these overlayers can apparently enhance the photoelectrochemical performance of the TNTAs/QDs. Under simulated solar illumination, the maximum photocurrent densities of the TNTAs/QDs with 10 cycles ZnO, 25 cycles TiO2, and 30 cycles Al2O3 overlayers are 5.0, 4.3, and 5.6 mA/cm2 at 1.0 V (vs. SCE), respectively. The photoelectrode with Al2O3 overlayer coating presents the superior performance, whose photocurrent density is 37 times and 1.6 times higher than those of the TNTAs and TNTAs/QDs, respectively. Systematic examination of the effects of various metal-oxide overlayers on the photoelectrochemical performance indicates that the enhancement by TiO2 and ZnO overcoatings can only ascribed to the decrease of the interfacial charge transfer impedance, besides which Al2O3 coating can passivate the surface states and facilitate the charge transfer kinetics. These results could be helpful to develop high-performance photoelectrodes in the photoelectrochemical applications.

mir-218-2 promotes glioblastomas growth, invasion and drug resistance by targeting CDC27.

Glioma has become a significant global health problem with substantial morbidity and mortality, underscoring the importance of elucidating its underlying molecular mechanisms. Recent studies have identified mir-218 as an anti-oncogene; however, the specific functions of mir-218-1 and mir-218-2 remain unknown, especially the latter. The objective of this study was to further investigate the role of mir-218-2 in glioma. Our results indicated that mir-218-2 is highly overexpressed in glioma. Furthermore, we showed that mir-218-2 is positively correlated with the growth, invasion, migration, and drug susceptibility (to ß-lapachone) of glioma cells. In vitro, the overexpression of mir-218-2 promoted glioma cell proliferation, invasion, and migration. In addition, the overexpression of mir-218-2 in vivo was found to increase glioma tumor growth. Accordingly, the inhibition of mir-218-2 resulted in the opposite effects. Cell division cycle 27 (CDC27), the downstream target of mir-218-2, is involved in the regulation of glioma cells. Our results indicate that the overexpression of CDC27 counteracted the function of mir-218-2 in glioma cells. These novel findings provide new insight in the application of mir-218-2 as a potential glioma treatment.