Tuning Molecular Composition for Better Cross-section Homogeneity of Thermal Oxidative Stabilized Polyacrylonitrile for Carbon Materials

Shiyu Liu,Yuan Ge,Baijun Liu,Zhongyu Fu,Xiaoyu Yu,Ming Yao Zhang,Hui Xuan Zhang 한국섬유공학회 2022 Fibers and polymers Vol.23 No.6

A strategy to improve the cross-section homogeneity of thermal oxidative stabilized polyacrylonitrile for carbonmaterials was provided in the present work. A kind of comonomer, dimethyl itaconate (DMI), which possesses two bulkyside groups was introduced into poly(acrylonitrile-co-itaconic acid). The efficiency of DMI in improving the cross-sectionhomogeneity of polyacrylonitrile films during thermal oxidative stabilization (TOS) processes and the properties of resultedPAN-based carbon materials were investigated in detail. It was found that DMI facilitated the formation of longer cyclicstructures, higher oxygen content, more homogeneous cross-section fracture morphology and denser structure during TOSprocess. DMI was also benefit for easing heat release. The presence of DMI also facilitated a smaller ID/IG value of thecarbonized PAN film and a bigger in-plane size of graphite crystals La.

Machining approaches with smart algorithms for ultrasonic precision machining

Zhongyu Liang,Yabo Liu,Nan Hu 한양대학교 청정에너지연구소 2023 Journal of Ceramic Processing Research Vol.24 No.5

Ultrasonic precision machining is an advanced manufacturing process that combines ultrasonic vibrations with traditionalmachining techniques to achieve high precision and efficiency. This article provides a comprehensive overview of the ultrasonicprecision machining process, its principles, applications, advantages, and challenges. It explores the various machiningparameters, tool configurations, and experimental setups employed in ultrasonic machining. Furthermore, the article discussesthe materials suitable for ultrasonic machining and the effects of ultrasonic vibrations on the machining performance andsurface quality. The review also highlights the recent advancements and emerging trends in ultrasonic precision machining,including hybrid machining approaches and intelligent process monitoring. Overall, this article aims to provide a valuableresource for researchers, engineers, and manufacturers interested in understanding and harnessing the potential of ultrasonicprecision machining.

Single-cell RNA sequencing analysis of human bone-marrow-derived mesenchymal stem cells and functional subpopulation identification

Xie Zhongyu,Yu Wenhui,Ye Guiwen,Li Jinteng,Zheng Guan,Liu Wenjie,Lin Jiajie,Su Zepeng,Che Yunshu,Ye Feng,Zhang Zhaoqiang,Wang Peng,Wu Yanfeng,Shen Huiyong 생화학분자생물학회 2022 Experimental and molecular medicine Vol.54 No.-

Mesenchymal stem cells (MSCs) are a common kind of multipotent cell in vivo, but their heterogeneity limits their further applications. To identify MSC subpopulations and clarify their relationships, we performed cell mapping of bone-marrow-derived MSCs through single-cell RNA (scRNA) sequencing. In our study, three main subpopulations, namely, the stemness subpopulation, functional subpopulation, and proliferative subpopulation, were identified using marker genes and further bioinformatic analyses. Developmental trajectory analysis showed that the stemness subpopulation was the root and then became either the functional subpopulation or the proliferative subpopulation. The functional subpopulation showed stronger immunoregulatory and osteogenic differentiation abilities but lower proliferation and adipogenic differentiation. MSCs at different passages or isolated from different donors exhibited distinct cell mapping profiles, which accounted for their corresponding different functions. This study provides new insight into the biological features and clinical use of MSCs at the single-cell level, which may contribute to expanding their application in the clinic.

Analytical Solution of Loosening Pressure Model for Shallow Tunnel Based on Pile-beam-arch Method

Tao Li,Zhongyu Zhang,Muchi Luo,Bo Liu,Yanlong Wang,Lingfeng Li 대한토목학회 2022 KSCE JOURNAL OF CIVIL ENGINEERING Vol.26 No.8

Loosening of earth pressure by tunnels is an important parameter for the structural design of subway stations, this study analyzes the difference between the loosening pressures of each span of a shallow multi-span tunnel station using the pile-beam-arch (PBA) method. By conducting a similarity model test of the PBA method, we simulate the complete excavation process. We study the sliding failure mode of the overlying soil of the shallow-buried station and the law of change of the loosening pressure of each span. A simplified calculation model for the loosening pressure of shallow buried multi-span tunnels by the cavity pile method was developed, and the applicability of the formulae and sensitivity analysis of the parameters were carried out. The results reveal that the loosening pressure of the mid-span is transferred to the stress of the side-span during tunnel excavation. This finding contradicts Terzaghi’s and Bierbaumer’s methods, which do not consider the influence of tunnel structure on the loosening pressure of the overlying soil. The side span relaxation pressure is only related to the soil capacity and the depth of burial of the tunnel This research can provide an important theoretical reference for the design of the overburden load and lateral confining pressure of the PBA structure design.

Elevated TRAF4 expression impaired LPS-induced autophagy in mesenchymal stem cells from ankylosing spondylitis patients

Jinteng Li,Peng Wang,Zhongyu Xie,Rui Yang,Yuxi Li,Xiaohua Wu,Hongjun Su,Wen Deng,Shan Wang,Zhenhua Liu,Shuizhong Cen,Yi Ouyang,Yanfeng Wu,Huiyong Shen 생화학분자생물학회 2017 Experimental and molecular medicine Vol.49 No.-

Ankylosing spondylitis (AS) is a type of autoimmune disease that predominantly affects the spine and sacroiliac joints. However, the pathogenesis of AS remains unclear. Some evidence indicates that infection with bacteria, especially Gram-negative bacteria, may have an important role in the onset and progression of AS. Recently, many studies have demonstrated that mesenchymal stem cells (MSCs) dysfunction may contribute to the pathogenesis of many rheumatic diseases. We previously demonstrated that MSCs from AS patients exhibited markedly enhanced osteogenic differentiation capacity in vitro under non-inflammatory conditions. However, the properties of MSCs from AS patients in an inflammatory environment have never been explored. Lipopolysaccharide (LPS), a proinflammatory substance derived from the outer membrane of Gram-negative bacteria, can alter the status and function of MSCs. However, whether MSCs from AS patients exhibit abnormal responses to LPS stimulation has not been reported. Autophagy is a lysosome-mediated catabolic process that participates in many physiological and pathological processes. The link between autophagy and AS remains largely unknown. The level of autophagy in ASMSCs after LPS stimulation remains to be addressed. In this study, we demonstrated that although the basal level of autophagy did not differ between MSCs from healthy donors (HDMSCs) and ASMSCs, LPS-induced autophagy was weaker in ASMSCs than in HDMSCs. Specifically, increased TRAF4 expression in ASMSCs impaired LPS-induced autophagy, potentially by inhibiting the phosphorylation of Beclin-1. These data may provide further insight into ASMSC dysfunction and the precise mechanism underlying the pathogenesis of AS.

Controllable Synthesis of Stereoregular Polyesters by Organocatalytic Alternating Copolymerizations of Cyclohexene Oxide and Norbornene Anhydrides

Han, Bing,Zhang, Li,Liu, Binyuan,Dong, Xiaofang,Kim, Il,Duan, Zhongyu,Theato, Patrick American Chemical Society 2015 Macromolecules Vol.48 No.11

<P>A facile strategy has been demonstrated for the selective synthesis of highly stereoregular polyesters with <I>cis</I>-2,3-(<I>exo</I>,<I> exo</I>) or <I>trans</I>-2,3-(<I>exo</I>,<I> endo</I>) repeating units by the organocatalysts mediated alternating copolymerization of cyclohexene oxide and norbornene anhydride (NA) stereoisomers. The geometrical structure of polyester can be tuned simply by modulating the type of NA isomers (<I>endo</I>- or <I>exo</I>-NA), monomer feed ratio, and reaction temperature. The <I>cis</I>- (>99%) and <I>trans</I>-polyesters (>99%) exhibit high glass transition temperature up to 129.8 and 115.9 °C, respectively. The resulting polyesters provide a versatile platform to incorporate various functional groups through the robust thiol–ene reaction of the pendant norbornenyl groups.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/mamobx/2015/mamobx.2015.48.issue-11/acs.macromol.5b00555/production/images/medium/ma-2015-00555x_0010.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/ma5b00555'>ACS Electronic Supporting Info</A></P>

ALKBH5 facilitates CYP1B1 mRNA degradation via m6A demethylation to alleviate MSC senescence and osteoarthritis progression

Ye Guiwen,Li Jinteng,Yu Wenhui,Xie Zhongyu,Zheng Guan,Liu Wenjie,Wang Shan,Cao Qian,Lin Jiajie,Su Zepeng,Li Dateng,Che Yunshu,Fan Shuai,Wang Peng,Wu Yanfeng,Shen Huiyong 생화학분자생물학회 2023 Experimental and molecular medicine Vol.55 No.-

Improving health and delaying aging is the focus of medical research. Previous studies have shown that mesenchymal stem cell (MSC) senescence is closely related to organic aging and the development of aging-related diseases such as osteoarthritis (OA). m6A is a common RNA modification that plays an important role in regulating cell biological functions, and ALKBH5 is one of the key m6A demethylases. However, the role of m6A and ALKBH5 in MSC senescence is still unclear. Here, we found that the m6A level was enhanced and ALKBH5 expression was decreased in aging MSCs induced by multiple replications, H2O2 stimulation or UV irradiation. Downregulation of ALKBH5 expression facilitated MSC senescence by enhancing the stability of CYP1B1 mRNA and inducing mitochondrial dysfunction. In addition, IGF2BP1 was identified as the m6A reader restraining the degradation of m6A-modified CYP1B1 mRNA. Furthermore, Alkbh5 knockout in MSCs aggravated spontaneous OA in mice, and overexpression of Alkbh5 improved the efficacy of MSCs in OA. Overall, this study revealed a novel mechanism of m6A in MSC senescence and identified promising targets to protect against aging and OA.

Temporal distribution, influencing factors and pollution sources of urban ambient air quality in Nanchong, China

Hong Zhou,Youping Li,Huifang Liu,Zhongyu Fan,Jie Xia,Shanli Chen,Yuxiang Zheng,Xiaocui Chen 대한환경공학회 2015 Environmental Engineering Research Vol.20 No.3

The PM10, SO₂ and NO₂ mass concentrations were obtained over five years from monitoring stations across Nanchong, a southwest city in China. Changes in urban air quality over time, as well as the factors influencing that change, were evaluated based on air pollutant concentrations, the Air Pollution Index (API), and the Comprehensive Pollution Index (P). The results showed that the total annual mean PM10, SO₂ and NO₂ concentrations over the five years studied were 61.1±1.1, 45.0±3.9 and 34.9±4.9 μg·m-3, respectively. The annual mean concentrations displayed a generally decreasing trend; lower than the annual mean second-level air quality limit. Meanwhile, the annual mean API values were in a small range of 52-53, the air quality levels were gradeⅡ, and P values were 1.06-1.21 less than the slight level (P ≤ 1.31). Total monthly mean PM10, SO₂, NO₂ concentrations, and API and P values were consistently higher in winter and spring than during autumn and summer. The results of a correlation analysis showed that temperature and pressure were the major meteorological factors influencing pollution levels. Pollution sources included industrial coal and straw burning, automobiles exhaust and road dust, fireworks, and dust storms.

Risk Factors for Poor Outcomes Following Minimally Invasive Discectomy: A Post Hoc Subgroup Analysis of 2-Year Follow-up Prospective Data

Zihao Chen,Lei He,Lijun Huang,Zhongyu Liu,Jianwen Dong,Bin Liu,Ruiqiang Chen,Liangming Zhang,Peigen Xie,Limin Rong 대한척추신경외과학회 2022 Neurospine Vol.19 No.1

Objective: A post hoc subgroup analysis of prospectively collected data from a randomized controlled trial was conducted to identify risk factors related to poor outcomes in patients who underwent minimally invasive discectomy. Methods: Patients were divided into satisfied and dissatisfied subgroups based on Oswestry Disability Index (ODI), visual analogue scale (VAS) back pain score (VAS-back) and leg pain score (VAS-leg) at short-term and midterm follow-up according to the patient acceptable symptom state threshold. Demographic characteristics, radiographic parameters, and clinical outcomes between the satisfied and dissatisfied subgroups were compared using univariate and multivariate analysis. Results: A total of 222 patients (92.1%) completed 2-year follow-up, and the postoperative ODI, VAS-back, and VAS-leg were significantly improved after surgery as compared to preoperatively. Multivariate analysis indicated older age (p = 0.026), lateral recess stenosis (p = 0.046), and lower baseline ODI (p = 0.027) were related to poor short-term functional improvement. Higher baseline VAS-back (p = 0.048) was associated with poor short-term relief of back pain, while absence of decreased sensation (p = 0.019) and far-lateral disc herniation (p = 0.004) were associated with poorer short-term relief of leg pain. Lumbar facet joint osteoarthritis was identified as a risk factor for poor functional improvement (p = 0.003) and relief of back pain (p = 0.031). Disc protrusion (p = 0.036) predicted poorer relief of back pain at midterm follow-up. Conclusion: In this study, several factors were identified to be predictive of poor surgical outcomes following minimally invasive discectomy. (ClinicalTrials.gov number: NCT01997086).