Mesogenic Ordering-Driven Self-Assembly of Liquid Crystalline Block Copolymers in Solution.

With the development of nanotechnology, the preparation of polymeric nanoparticles with nicely defined structures has been well-developed, and the functionalization and subsequent applications of the resultant nanostructures are becoming increasingly important. Particularly, by introducing mesogenic ordering as the driving force for the solution-state self-assembly of liquid crystalline (LC) block copolymers (BCPs), micellar nanostructures with different morphologies, especially anisotropic morphologies, can be easily prepared. This review summarizes the recent progress in the solution-state self-assembly of LC BCPs and is mostly focused on four main related aspects, including an in-depth understanding of the mesogenic ordering-driven self-assembly, precise assembly methods, utilization of these methods to fabricate hierarchical structures, and the potential applications of these well-defined nanostructures. We hope not only to make a systematic summary of previous studies but also to provide some useful thinking for the future development of this field.

Controllable One-Step Assembly of Uniform Liquid Crystalline Block Copolymer Cylindrical Micelles by a Tailored Nucleation-Growth Process and Their Application as Tougheners.

The fabrication of uniform cylindrical nanoobjects from soft materials has attracted tremendous research attention from both fundamental research and practical application points of view but has also posed outstanding challenges in terms of their preparation. Herein, we report a one-step method to assemble cylindrical micelles (CMs) with highly controllable lengths from a single liquid crystalline block copolymer by an in situ nucleation-growth strategy. By adjusting the assembly conditions, the lengths of the CMs are controlled from hundreds of nanometers to micrometers. Several influencing factors are systematically investigated to comprehensively understand the process. Particularly, the solvent quality is found determinative in either enhancing or suppressing the nucleation process to produce shorter and longer CMs, respectively. Taking advantage of this strategy, the lengths of CMs can be nicely controlled over a wide concentration range of four orders of magnitude. Lastly, CMs are produced on decent scales and applied as additives to dramatically toughen glassy plastic matrix, revealing an unprecedented length-dependent toughening effect.

In situ Nucleation-Growth Strategy for Controllable Heterogeneous Supramolecular Polymerization of Liquid Crystalline Block Copolymers and Their Hierarchical Assembly.

The self-assembly morphologies of subunits are largely governed by thermodynamics, which plays a less important role in dimensional control. Particularly for one-dimensional assemblies from block copolymers (BCPs), the negligible energy difference between short and long ones imposes great challenges in length control. Herein, we report that by incorporating additional polymers to induce in situ nucleation and trigger the subsequent growth, controllable supramolecular polymerization driven by mesogenic ordering effect could be realized from liquid crystalline BCPs. The length of the resultant fibrillar supramolecular polymers (SP) is controlled by tuning the ratio between nucleating and growing components. Depending on the choice of BCPs, the SPs can be homopolymer-like, heterogeneous triblock, and even pentablock copolymer-like. More interestingly, with insoluble BCP as a nucleating component, amphiphilic SPs are fabricated, which can undergo spontaneous hierarchical assembly.

PM2.5 Aggravated OVA-Induced Epithelial Tight Junction Disruption Through Fas Associated via Death Domain-Dependent Apoptosis in Asthmatic Mice.

BACKGROUND: Exposure to air pollutants cause exacerbation of asthma, but the experimental evidence and the mechanisms still need to be collected and addressed. METHODS: Asthma model was constructed by ovalbumin (OVA) combined with or without airborne fine particulate matter 2.5 (PM2.5) exposure. Lung sections were stained by hematoxylin-eosin staining (H&E) and Masson's trichrome. RNA-seq and gene set enrichment analysis (GSEA) was performed to identify the key pathway. TdT mediated dUTP Nick End Labeling (TUNEL) assay, real-time qPCR, Western blot, immunofluorescence and lentivirus transfection were applied for mechanism discovery. RESULTS: In this study, we found PM2.5 aggravated airway inflammation in OVA-induced asthmatic mice. RNA-seq analysis also showed that epithelial mesenchymal transition (EMT) was enhanced in OVA-induced mice exposed to PM2.5 compared with that in OVA-induced mice. In the meantime, we observed that apoptosis was significantly increased in asthmatic mice exposed to PM2.5 by using GSEA analysis, which was validated by TUNEL assay. By using bioinformatic analysis, Fas associated via death domain (FADD), a new actor in innate immunity and inflammation, was identified to be related to apoptosis, EMT and tight junction. Furthermore, we found that the transcript and protein levels of tight junction markers, E-cadherin, zonula occludens (ZO)-1 and Occludin, were decreased after PM2.5 exposure in vivo and in vitro by using RT-qPCR and immunofluorescence, with the increased expression of FADD. Moreover, down-regulation of FADD attenuated PM2.5-induced apoptosis and tight junction disruption in human airway epithelial cells. CONCLUSION: Taken together, we demonstrated that PM2.5 aggravated epithelial tight junction disruption through apoptosis mediated by up-regulation of FADD in OVA-induced model.

An integrative analysis identifying transcriptional features and key genes involved in COVID-19.

Aim: To elucidate the transcriptional characteristics of COVID-19. Materials & methods: We utilized an integrative approach to comprehensively analyze the transcriptional features of both COVID-19 patients and SARS-CoV-2 infected cells. Results: Widespread infiltration of immune cells was observed. We identified 233 genes that were codifferentially expressed in both bronchoalveolar lavage fluid and lung samples of COVID-19 patients. Functional analysis suggested upregulated genes were related to immune response such as neutrophil activation and antivirus response, while downregulated genes were associated with cell adhesion. Finally, we identified LCN2, STAT1 and UBE2L6 as core genes during SARS-CoV-2 infection. Conclusion: The identification of core genes involved in COVID-19 can provide us with more insights into the molecular features of COVID-19.

Dual Roles of Amino-Functionalized Silicon Quantum Dots (SiQDs) for Visible-Light-Induced Surface-Initiated PET-RAFT Polymerization on Substrates.

Silicon quantum dots (SiQDs) are explored for the first time as an efficient photocatalyst for visible-light-regulated reversible addition-fragmentation chain transfer (RAFT) polymerization. The fluorescence quenching confirmed the photoinduced electron transfer (PET) between SiQDs and RAFT reagents. Besides all features of controlled radical polymerization, the SiQDs catalyzed PET-RAFT polymerization also exhibit good temporal control, high chain-end fidelity, and versatility with diverse monomers. Moreover, amino-functionalized SiQDs can be easily coated on the surface of substrates (silicon wafer) owing to the electrostatic interaction, and play a dual role of polymer-substrate connector and photocatalyst for the surface-initiated PET-RAFT polymerization. The SiQD-coated wafer was also proved to be an efficient recycle photocatalyst for PET-RAFT polymerization.

Light and magnetism dual-gated photoinduced electron transfer-reversible addition-fragmentation chain transfer (PET-RAFT) polymerization.

A novel raspberry-like γ-Fe2O3@carbon dot (CD) nanocatalyst was prepared and applied for photoinduced electron transfer-reversible addition-fragmentation chain transfer (PET-RAFT) polymerization. The nanocatalyst was found to be an efficient photocatalyst in visible light-regulated PET-RAFT polymerization owing to the oxidative quenching mechanism between the photoexcited γ-Fe2O3@CDs and the RAFT agent in the PET process. Notably, polymerization can be reversibly ceased in the absence of light or under an external magnetic field. The superparamagnetic nature and high saturation magnetization value (∼30.4 emu g-1) of the nanocatalyst contribute to convenient recycling of the nanocatalyst after polymerization. The PET-RAFT polymerization with the nanocatalyst before and after recycling was investigated, which displayed all the characteristics of controlled/living polymerization systems.

[Effects of scalp acupuncture on expression of hippocampal MMP-9 in cerebral ischemia injury rats].

OBJECTIVE: To observe the effect of scalp-acupuncture on the expression of matrix metalloproteinase 9 (MMP-9) in the endothelium of the microvessels in the hippocampal CA 3 area in local cerebral ischemia (CI) rats, so as to study its underlying mechanism in improving CI. METHODS: Eighty male Wistar rats were randomized into normal control (n = 8), sham-operation (n = 8), CI model (n = 32), and scalp-acupuncture (n = 32) groups. The later two groups were further equally and respectively divided into 1, 3, 5 and 10 d subgroups. CI model was established by occlusion of the middle cerebral artery (MCAO). "Baihui" (GV 20) and "Qubin"(GB 7) were punctured with filiform needles and stimulated by twirling the needle at a frequency of about 200 revolutions/min for 1 min. The needles were retained for 30 min and re-manipulated once again every 10 min. The treatment was given once daily, continuously for 1, 3, 5 and 10 days respectively in different subgroups. MMP-9 immunoactivity of hippocampal CA 3 area was assayed by immunohistochemistry (SABC). RESULTS: Following CI, the CI rats' neural deficit scores in the model and scalp-acupuncture (treatment) groups had no apparent difference (P > 0.05). After acupuncture, the neural deficit score in the treatment group decreased gradually, and was significantly lower than that in the 10 d subgroup of model group (P < 0.05). Compared with the 1, 3, 5 and 10 d subgroups of control group, the total area and integral optical density (IOD) values of MMP-9 immunoactivity of hippocampal CA 3 area were all increased significantly in the corresponding 4 subgroups of model group (P < 0.01). Compared with the 3, 5 and 10 d subgroups of the model group, the total area and IOD values of MMP-9 immunoreaction positive products in the corresponding 3 subgroups of scalp-acupuncture group were decreased significantly (P < 0.05, P < 0.01). CONCLUSION: Scalp-acupuncture can effectively down-regulate MMP-9 expression in the hippocampal CA 3 area in focal cerebral ischemia rats, which may contribute to its effect in improving the neural deficit.

[Bibliometrics study on dominant diseases in modern acupuncture clinic].

OBJECTIVE: To find out the dominant diseases in the clinic of modern acupuncture. METHODS: By means of bibliometrics, clinical acupuncture study literatures from 1978 to 2004, searched from CBM database, were sorted and counted to show the different clinical utilizing quantities and developing trends of different disease groups in the acupuncture clinic. RESULTS: Obviously dominant type: nervous system diseases; mature type: motor system diseases; developing type: 3 kind of diseases including psychosis; premature type: diseases related with surgery; steady type: 3 kind of diseases including digestive system diseases (diseases of liver and gallbladder are not included); pre-developing diseases: 5 kind of diseases including otorhinolaryngologic diseases. CONCLUSION: Among all these types, obvious advantage type and mature type are the most distinguishing. Developing type has the most significant ascending trend. Premature type has relatively strong developing potentiality.