Boron-Nitrogen-Embedded Polycyclic Aromatic Hydrocarbon-Based Controllable Hierarchical Self-Assemblies through Synergistic Cation-π and C-H···π Interactions for Bifunctional Photo- and Electro-Catalysis.

Boron-Nitrogen-embedded polycyclic aromatic hydrocarbons (BN-PAHs) as novel π-conjugated systems have attracted immense attention owing to their superior optoelectronic properties. However, constructing long-range ordered supramolecular assemblies based on BN-PAHs remains conspicuously scarce, primarily attributed to the constraints arising from coordinating multiple noncovalent interactions and the intrinsic characteristics of BN-PAHs, which hinder precise control over delicate self-assembly processes. Herein, we achieve the successful formation of BN-PAH-based controllable hierarchical assemblies through synergistically leveraged cation-π and C-H···π interactions. By carefully adjusting the solvent conditions in two progressive assembly hierarchies, the one-dimensional (1D) supramolecular assemblies with "rigid yet flexible" assembled units are first formed by cation-π interactions, and then they can be gradually fused into two-dimensional (2D) structures under specific C-H···π interactions, thus realizing the precise control of the transformation process from BN-PAH-based 1D primary structures to 2D higher-order assemblies. The resulting 2D-BNSA, characterized by enhanced electrical conductivity and ordered 2D layered structure, provides anchoring and dispersion sites for loading two appropriate nanocatalysts, thus facilitating the efficient photocatalytic CO2 reduction (with a remarkable CH4 evolution rate of 938.7 µmol g-1 h-1) and electrocatalytic acetylene semihydrogenation (reaching a Faradaic efficiency for ethylene up to 98.5%).

Effect of pre-plasma on terahertz radiation from two-color laser plasma filaments in a collinear geometry.

Terahertz (THz) radiation from air plasma in the presence of pre-plasma in a collinear geometry is investigated experimentally, where the pre-plasma is formed by a pre-pulse with a Gaussian beam profile and the measured THz radiation is driven by a main laser pulse. The pre-plasma has a de-focusing effect for the main pulse passing through it, which reduces the effective length of the plasma filament formed by the main laser pulse for THz radiation. It is found that only the part not overlapped by the pre-plasma can actually produce THz radiation. Thus, the amplitude of the THz pulse driven by the main pulse can be modified by changing the spatial separation between two plasma filaments. The experimental observations are qualitatively in agreement with our numerical simulation results. It is also found that the change of the time delay between the pre-pulse and the main pulse does not change the THz radiation amplitude for a given spatial separation. This study suggests a practical way for the manipulation of THz waves through an interaction between laser plasma filaments.

Millijoule Terahertz Radiation from Laser Wakefields in Nonuniform Plasmas.

We report the experimental measurement of millijoule terahertz (THz) radiation emitted in the backward direction from laser wakefields driven by a femtosecond laser pulse of few joules interacting with a gas target. By utilizing frequency-resolved energy measurement, it is found that the THz spectrum exhibits two peaks located at about 4.5 and 9.0 THz, respectively. In particular, the high frequency component emerges when the drive laser energy exceeds 1.26 J, at which electron acceleration in the forward direction is detected simultaneously. Theoretical analysis and particle-in-cell simulations indicate that the THz radiation is generated via mode conversion from the laser wakefields excited in plasma with an up-ramp profile, where radiations both at the local electron plasma frequency and its harmonics are produced. Such intense THz sources may find many applications in ultrafast science, e.g., manipulating the transient states of matter.

Thermo-Induced Bathochromic Emission in Columnar Discotic Liquid Crystals Realized by Intramolecular Planarization.

Most organic thermochromic fluorescent materials exhibit thermo-induced hypsochromic emission due to the formation of excimers in ordered molecular solids; however, it is still a challenge to endow them with bathochromic emission despite its significance in making up the field of thermochromism. Here, a thermo-induced bathochromic emission in columnar discotic liquid crystals is reported realized by intramolecular planarization of the mesogenic fluorophores. A three-armed discotic molecule of dialkylamino-tricyanotristyrylbenzene was synthesized, which preferred to twist out of the core plane to accommodate ordered molecular stacking in hexagonal columnar mesophases, giving rise to bright green monomer emission. However, intramolecular planarization of the mesogenic fluorophores occurred in isotropic liquid increasing the conjugation length, and as a result led to thermo-induced bathochromic emission from green to yellow light. This work reports a new concept in the thermochromic field and provides a novel strategy to achieve fluorescence tuning from intramolecular actions.

Spectral control of terahertz radiation from inhomogeneous plasma filaments by tailoring two-color laser beams.

Terahertz (THz) radiation from an inhomogeneous plasma filament generated by focusing two-color femtosecond laser pulses into argon gas filled in a chamber is investigated experimentally by tailoring the Gaussian pump laser beams with an iris, where broadband THz emission over 10 THz is produced. It is found that the collected far-field THz radiation includes not only coherent but also partial-coherent components of the THz waves, which are emitted from the different parts of the inhomogeneous plasma filament with different plasma densities, contributing correspondingly to the different frequencies of the THz spectrum. Our results suggest that the THz spectrum can be manipulated by controlling the plasma density distribution of the filaments.

Phase evolution of terahertz radiation from femtosecond laser-induced air plasma.

The phase evolution of terahertz (THz) radiation from single-color femotsecond laser-induced air plasma controlled by a DC-bias is investigated experimentally. When the DC-bias is moved from the end to the beginning of the laser plasma filament, the produced THz waveform is advanced temporally, and its carrier-envelope phase is changed. Our phase spectrum analysis suggests that the slope and the intercept of the phase spectrum, respectively, determine the temporal shift and the carrier-envelope phase of the THz waveform. Therefore, the observed THz waveform evolution is mainly due to the THz propagation effect in plasma filament and the Gouy phase shift associated with the detection scheme. This Letter also illustrates explicitly the temporal order of THz radiation from different parts of a filament.

Phase evolution of terahertz radiation from femtosecond laser-induced air plasma: publisher's note.

This publisher's note contains corrections to Opt. Lett.45, 1966 (2020).OPLEDP0146-959210.1364/OL.385292.

Controllable Terahertz Radiation from a Linear-Dipole Array Formed by a Two-Color Laser Filament in Air.

We demonstrate effective control on the carrier-envelope phase and angular distribution as well as the peak intensity of a nearly single-cycle terahertz pulse emitted from a laser filament formed by two-color, the fundamental and the corresponding second harmonics, femtosecond laser pulses propagating in air. Experimentally, such control has been performed by varying the filament length and the initial phase difference between the two-color laser components. A linear-dipole-array model, including the descriptions of both the generation (via laser field ionization) and propagation of the emitted terahertz pulse, is proposed to present a quantitative interpretation of the observations. Our results contribute to the understanding of terahertz generation in a femtosecond laser filament and suggest a practical way to control the electric field of a terahertz pulse for potential applications.

Treatment Efficacy and Risk Factors of Neurobrucellosis.

BACKGROUND: This study aimed to analyze the risk factors and treatment efficacy of neurobrucellosis. MATERIAL/METHODS: A cross-sectional epidemiologic survey was carried out in 557 patients with brucellosis by specially trained neurologic clinicians. Sixty-six patients with neurobrucellosis were treated with doxycycline, rifampicin, and ceftriaxone sodium as standard medication and evaluated for efficacy on a regular basis. RESULTS: (1) Symptoms improved in most patients after 6 weeks of treatment, which demonstrated a favorable efficacy. (2) Cross-sectional epidemiologic survey suggested that sex, nationality, and regional distribution were not related to nervous system damage in patients with brucellosis (P>0.05), whereas age and duration of disease were related factors. Increased age as well as a prolonged duration of disease were risk factors for nervous system damage in patients with brucellosis (P<0.05). CONCLUSIONS: (1) Doxycycline, rifampicin, and third-generation cephalosporins should be considered both standard and first-choice medications for neurobrucellosis. Treatment should last for at least 6 weeks. Standardized, sufficient, and combined medication is recommended for better efficacy and prognosis. (2) Age and duration of disease are risk factors for neurobrucellosis, whereas sex, nationality, and regional distribution are not. Older patients with a prolonged duration of disease are more likely to develop neurobrucellosis.

miR-16-1 promotes the aberrant α-synuclein accumulation in parkinson disease via targeting heat shock protein 70.

There is striking evidence that heat shock protein 70 (Hsp70) negatively regulates α-synuclein aggregation, which plays a significant role in the formation and progression of Parkinson disease (PD). However, how the Hsp70 in neurons fails to prevent or even reverse α-synuclein aggregation and toxicity in PD still remains to be determined. In the present study, we constructed an α-synuclein-overexpressed human neuroblastoma cell line, SH-SY5Y-Syn, in which the blockage of Hsp70 promoted α-synuclein aggregation. And we also found that miR-16-1 downregulated Hsp70 and promoted α-synuclein aggregation in the SH-SY5Y-Syn cells. This study revealed a novel regulatory mechanism of Hsp70 expression, which might contribute to the PD development.

Toxicity assessment of Cucurbita pepo cv Dayangua and its effects on gut microbiota in mice.

BACKGROUND: Cucurbita pepo cv Dayangua (CPD) is an edible plant with diverse pharmacological properties. The current research on CPD has primarily focused on initial investigations of its chemical composition and pharmacological effects, and no comprehensive toxicity assessment has been conducted to date. METHODS: In the present study, the toxicity of CPD was evaluated through both acute and sub-chronic oral toxicity tests in mice. 16S rDNA sequencing was used to analyze the composition of the gut microbiota of mice at different time points to observe the effect of CPD on these microbial communities. RESULTS: In the acute toxicity test, CPD exhibited low toxicity, with a median lethal dose (LD50) > 2000 mg/kg. The sub-chronic toxicity test indicated that CPD administration at doses of 200, 400, and 600 mg/kg did not cause mortality or significant organ damage in mice. Furthermore, analysis of the gut microbiota after gavage administration of CPD at 400 and 600 mg/kg revealed an improved abundance of some beneficial gut bacteria. CONCLUSIONS: In summary, no acute or sub-chronic toxic effects were observed in mice following the oral administration of CPD. CPD did not affect the structure and diversity of the gut microbiota and may contribute to an increase in the number of beneficial gut bacteria.

Review of knockout technology approaches in bacterial drug resistance research.

Gene knockout is a widely used method in biology for investigating gene function. Several technologies are available for gene knockout, including zinc-finger nuclease technology (ZFN), suicide plasmid vector systems, transcription activator-like effector protein nuclease technology (TALEN), Red homologous recombination technology, CRISPR/Cas, and others. Of these, Red homologous recombination technology, CRISPR/Cas9 technology, and suicide plasmid vector systems have been the most extensively used for knocking out bacterial drug resistance genes. These three technologies have been shown to yield significant results in researching bacterial gene functions in numerous studies. This study provides an overview of current gene knockout methods that are effective for genetic drug resistance testing in bacteria. The study aims to serve as a reference for selecting appropriate techniques.

Research Progress of Dendritic Cell Surface Receptors and Targeting.

Dendritic cells are the only antigen-presenting cells capable of activating naive T cells in humans and mammals and are the most effective antigen-presenting cells. With deepening research, it has been found that dendritic cells have many subsets, and the surface receptors of each subset are different. Specific receptors targeting different subsets of DCs will cause different immune responses. At present, DC-targeted research plays an important role in the treatment and prevention of dozens of related diseases in the clinic. This article focuses on the current status of DC surface receptors and targeted applications.

Multistep sequence-controlled supramolecular polymerization by the combination of multiple self-assembly motifs.

The precise sequence control of polymer chain is an important research topic of polymer chemistry. Although some methods such as iterative synthesis and supramolecular polymerization have been developed to fabricate sequence-controllable polymer, it is still a great challenge to consecutively prepare multiple supramolecular polymers with different sequence structures. In this work, through the reasonable utilization of assembly motifs, we integrated multiple host-guest recognitions and metal coordination interactions to prepare different sequence-controlled supramolecular polymers by a multistep assembly strategy. This research provides inspiration for the design and preparation of supramolecular polymers with different sequence structures.

Identification of cerebrospinal fluid metabolites as biomarkers for neurobrucellosis by liquid chromatography-mass spectrometry approach.

Neurobrucellosis is the most morbid form in brucellosis disease. Metabolomics is an emerging method which intends to explore the global alterations of various metabolites in samples. We aimed to identify metabolites in cerebrospinal fluid (CSF) as biomarkers that were potentially unique for neurobrucellosis. CSF samples from 25 neurobrucellosis patients and 25 normal controls (uninfected patients with hydrocephalus) were collected for metabolite detection using liquid chromatography-mass spectrometry (LC-MS) approach. Inflammatory cytokines in CSF were measured with Enzyme-linked immunosorbent assay (ELISA). The base peak chromatogram in CSF samples showed that small-molecule metabolites were well separated. Principal Component Analysis (PCA) analysis exhibited the examined samples were arranged in two main clusters in accordance with their group. Projection to Latent Structures Discriminant Analysis (PLS-DA) revealed there was a noticeable separation between neurobrucellosis and normal groups. Orthogonal Partial Least-Squares-Discriminant Analysis (OPLS-DA) could responsibly illuminate the differences between neurobrucellosis and normal controls. Neurobrucellosis showed a total of 155 differentiated metabolites. Prominent potential biomarkers including 30 metabolites were then selected out, regarded as more capable of distinguishing neurobrucellosis. TNF-α and IL-6 in CSF were remarkably increased in neurobrucellosis. We presented the heatmaps and correlation analyses among the identified 30 potential biomarkers. In conclusion, this study showed that CSF metabolomics based on LC-MS could distinguish neurobrucellosis patients from normal controls. Our data offered perspectives for diagnosis and treatment for neurobrucellosis.

Perylene Bisimide-Based Luminescent Liquid Crystals with Tunable Solid-State Light Emission.

Perylene bisimides are among the most studied building blocks for supramolecular assemblies in the fabrication of optoelectronic devices for their exceptional optical and electronic properties; however, developing perylene bisimide-based luminescent liquid crystals remains a challenge for the strong π-stacking tendency of the large planar aromatic core to quench the emission. We here reported a novel strategy to achieve luminescent liquid crystals based on perylene bisimides by introducing a conformation-adjustable core to control the molecular stacking arrangement of planar perylene bisimides in the solid state. The emission wavelength is in the deep-red region with a luminescence efficiency of up to 10%. Fluorescence properties of the liquid crystals can be further regulated by photoisomerization-induced structural evolution from columnar to lamellar mesophases. These luminescent liquid crystals are also able to not only exhibit strong emission at high temperatures but also show attractive thermochromic luminescence tuning behaviors. This work provides a new strategy for the design and development of novel solid-state luminescent materials with potential for various optoelectronic applications.

Neuroprotective effects of lycopene pretreatment on transient global cerebral ischemia­reperfusion in rats: The role of the Nrf2/HO­1 signaling pathway.

The present study aimed to investigate the neuroprotective effect of lycopene in a mouse model of bilateral common carotid artery occlusion (BCCAO) and the role of the Nrf2/HO­1 signaling pathway. A total of 60 male C57BL/6 mice, aged 12 weeks and weighing 20­24 g, were used in the present study. The mice were randomly assigned to three groups: Control, BCCAO and BCCAO + lycopene. The neurological score was assessed 24, 48 or 72 h following BCCAO. Hematoxylin and eosin staining, and terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) were performed to detect neuronal death and survival. The production of glutathione (GSH) and reactive oxygen species were detected to investigate the oxidative stress. The expression levels of nuclear factor erythroid 2­related factor (Nrf2) and Heme oxygenase­1 (HO­1) were determined by western blotting. Lycopene significantly improved the neurological score in the BCCAO mice. It attenuated neuronal apoptosis, as indicated by TUNEL staining, and attenuated the oxidative stress induced by global ischemia. Lycopene increased the expression levels of Nrf2 and HO­1, indicating that the Nrf2/HO­1 signaling pathway may be involved in the neuroprotective effect of lycopene. The present study revealed that lycopene protects the brain from global ischemic injury, which is associated with its antiapoptotic effect and the activation of the Nrf2/HO­1 signaling pathway.

Downregulated miR-29c correlates with increased BACE1 expression in sporadic Alzheimer's disease.

BACKGROUND: Beta-site Amyloid precursor protein Cleaving Enzyme 1 (BACE1) is conceived as a potential target for therapies against Alzheimer disease (AD) which is characterized by the accumulation of plaques formed of short ß-amyloid (APPß) peptides. Recently, such microRNAs, as miR-29a, miR-29b-1 have been shown to correlate with abnormally high levels of BACE1 and APPß in sporadic AD. METHODS: In order to confirm whether miR-29c correlates with the BACE1 upregulation in sporadic AD, we firstly evaluated the expression of miR-29c and BACE1, the APPß accumulation in sporadic AD brain tissues and analyzed the correlation of miR-29c with BACE1. Then we determined the regulation of miR-29c in human heuroblastoma SH-SY5Y cells on the BACE1 expression and APPß accumulation. And finally we determined the targeting to 3' UTR of BACE1 by miR-29c by a luciferase reporter. RESULTS: It was demonstrated that miR-29c was downregulated in sporadic AD brains, in an association with an upregulation of BACE1 in both mRNA and protein level of BACE1, and also an elevated APPß accumulation. And the manipulated high level of miR-29c with miR-29c mimics transfection significantly reduced the protein level of BACE1 and APPß accumulation in human neuroblastoma SH-SY5Y cells. Further luciferase reporter assay demonstrated that miR-29c targets the 3' UTR of BACE1 and downregulated the BACE1 in HEK293 cells. CONCLUSION: Present study indicated that miR-29c was downregulated in sporadic AD brains, and it targeted the 3' UTR of BACE1, reduced the BACE1 expression, and downregulated the APPß accumulation in vitro.

Heat shock protein 70 induction by glutamine increases the α-synuclein degradation in SH-SY5Y neuroblastoma cells.

Functional defects in heat shock proteins (HSPs), e.g. Hsp70, have been reported to have a key role in Parkinson's disease (PD). Overexpressed Hsp70 re­folds aggregated α­synuclein to generate the non­toxic and non­aggregated form. Thus, Hsp70 is a well­defined therapeutic target, and Hsp70 promotion is an efficient strategy to prevent or even reverse the α­synuclein­induced toxicity in PD. The present study investigated the promotion of Hsp70 expression in SH­SY5Y neuroblastoma cells by glutamine (Gln), which has recently been recognized to induce Hsp70 expression. Furthermore, the role of heat shock factor (HSF)­1 in the Gln­mediated upregulation of Hsp70 expression was investigated. In addition, the regulatory role of Gln in α­synuclein degradation in α­synuclein­overexpressing SH­SY5Y cells was determined. The results of the present study demonstrated that Gln treatment significantly upregulated Hsp70 expression at the mRNA as well as the protein level in a dose­dependent and time­dependent manner. Gln­induced Hsp70 upregulation was found to be HSF­1­dependent, as HSF­1 knockdown abrogated the Hsp70 upregulation by Gln in α­synuclein­overexpressing SH­SY5Y cells. In conclusion, present study confirmed that Gln upregulates Hsp70 expression in SH­SY5Y neuroblastoma cells in an HSF­1­dependent manner. The upregulation of Hsp70 by Gln increases the α­synuclein degradation. Therefore, Gln may be a potential therapeutic agent to prevent α­synuclein aggregation in PD.