Investigating Various Factors Affecting the Long-Term Compressive Strength of Heat-Cured Fly Ash Geopolymer Concrete and the Use of Orthogonal Experimental Design Method

Hongen Zhang,Lang Li,Prabir Kumar Sarker,Tao Long,Xiaoshuang Shi,Qingyuan Wang,Gaochuang Cai 한국콘크리트학회 2020 International Journal of Concrete Structures and M Vol.14 No.1

This work quantified the hierarchy of the influence of three common mixture design parameters on the compressive strength and the rate of strength increase over the long term of low-calcium fly ash geopolymer concrete (FAGC) through designing 16 mixtures by the orthogonal experimental design (OED) method. The parameters used in the study were liquid to fly ash (L/FA) ratio, sodium hydroxide concentration (SHC) and sodium silicate solution to sodium hydroxide solution (SS/SH) ratio. The L/FA ratio showed little effect on compressive strength when it was varied from 0.40 to 0.52. SHC showed the greatest influence on compressive strength with little impact on the rate of strength increase after the initial heat curing. Even though the SS/SH ratio showed a small effect on the initial compressive strength, it had a considerable influence on the rate of strength increase over the long term. It was found that the compressive strength at 480 days was positively related to the Na₂O/SiO₂ molar ratio when it was varied from 0.49 to 0.80 and the Si/Al molar ratio was increased up to 1.87. Analysis of the failure types of specimens demonstrated that compressive strength of FAGC was associated with the strength of the mortar–aggregate interface zone (MAIZ).

Design review on indoor environment of museum buildings in hot-humid tropical climate

Ogwu, Ikechukwu,Long, Zhilin,Okonkwo, Moses M.,Zhang, Xuhui,Lee, Deuckhang,Zhang, Wei Techno-Press 2022 Advances in computational design Vol.7 No.4

Museum buildings display artefacts for public education and enjoyment, ensuring their long-term safety and the comfort of visitors by following strict indoor environment control protocols using mechanical Heating, Ventilation and Air Conditioning (HVAC) systems to keep the (environmental) variables at a fixed comfort level. Maintaining this requires constant supply of energy currently mostly sourced from the combustion of fossil fuels which exacerbates climate change. However, a review on the effects of the indoor environmental variables on museum artefacts as well as museum visitors revealed that there is no specific point at which artefact deterioration occurs, and that there are wide ranges of conditions that guarantee the long-term safety of artefacts and human comfort. Visits to museum buildings in hot-humid tropical climate of Nigeria revealed that strict indoor environmental practices were adopted. Even when appropriate micro-climatic conditions are provided for artefacts, mechanical HVAC systems remain necessary for visitor comfort because almost no consideration is given to natural ventilation. With the current global push towards energy management, this paper reviewed passive environmental control practices, architectural design strategies, and discusses the adaptation of double skin façade with jali screens, and the notion of smart materials, which can satisfy the range of requirements for the long-term safety of artefacts and levels of human comfort in buildings in hot-humid tropical climate, without mechanical HVAC systems. This review would inspire more discussions on passive, energy efficient, smart and climate responsible popular architecture, challenging current thinking on the impact of the more accepted representative architecture.

Magnetocaloric effect in La_1-xSr_xCoO₃ undergoing a second-order phase transition

Long, Phan The,Manh, T.V.,Ho, T.A.,Dongquoc, Viet,Zhang, P.,Yu, S.C. Elsevier 2018 CERAMICS INTERNATIONAL Vol.44 No.13

<P><B>Abstract</B></P> <P>We have prepared rhombohedral La<SUB>1-x</SUB>Sr<SUB>x</SUB>CoO<SUB>3-δ</SUB> (<I>x</I> = 0.2–0.5) compounds with a mass density <I>ρ</I> ≈ 5.5 g/cm<SUP>3</SUP>. Their magnetocaloric (MC) effect is studied via the magnetic-entropy change (Δ<I>S</I> <SUB>m</SUB>) and relative cooling power (<I>RCP</I>), which are calculated from initial magnetization data recorded at different temperatures. Results reveal that the Δ<I>S</I> <SUB>m</SUB> magnitude is maximum (Δ<I>S</I> <SUB>max</SUB>) around the ferromagnetic-paramagnetic phase transition and dependent on both the applied-field (<I>H</I>) magnitude and Sr content (<I>x</I>). For <I>H</I> = 50 kOe, |Δ<I>S</I> <SUB>max</SUB>| can be tuned in the range of 1.6–2.7 J/kg K, corresponding to <I>RCP</I> values of 89–141 J/kg. Among the studied La<SUB>1-x</SUB>Sr<SUB>x</SUB>CoO<SUB>3-δ</SUB> samples, the samples with <I>x</I> = 0.3–0.5 have the largest |Δ<I>S</I> <SUB>max</SUB>| values. If combining these samples as MC blocks in refrigeration application, the working temperature range of a cooling device could range from 204 to ~280 K, with |Δ<I>S</I> <SUB>max</SUB>| stable at ~2.6 J/kg K and <I>RCP</I> ≈ 198 J/kg. We have also assessed the phase-transition type and magnetic order and found La<SUB>1-x</SUB>Sr<SUB>x</SUB>CoO<SUB>3-δ</SUB> undergoing a second-order phase transition. Magnetic order tends to change from the long-range type to the short-range one when <I>x</I> varies from 0.2 to 0.5. This is in good agreement with the results obtained from the analysis of critical behavior.</P>

Dry reforming of methane over Ni/SBA-15 catalysts prepared by homogeneous precipitation method

Qiulin Zhang,Jing Wang,Ping Ning,Tengfei Zhang,Mingzhi Wang,Kaixian Long,Jianhong Huang 한국화학공학회 2017 Korean Journal of Chemical Engineering Vol.34 No.11

Ni/SBA-15 catalyst was prepared by homogeneous precipitation method (Ni-HP) and used for dry reforming of methane (DRM). The related characterization results indicated that the Ni particles were highly dispersed with a size range of 2-5 nm. Compared with Ni/SBA-15 catalyst prepared by impregnation (Ni-IM), the reduction temperature of Ni-HP obtained from H2-TPR was greatly improved, suggesting the stronger metal-support interaction. After reacting at 700 oC for 100 h, the CH4 conversion of DRM over Ni-HP catalyst slightly decreased from 74.5% to 73.8%. While, for the Ni-IM catalyst, the CH4 conversion dropped from 61.7% to 37.3%. Furthermore, the average particle size of Ni-HP was 3.7 nm and 4.7 nm before and after the long-time stability test, respectively, ascribed to the good antisintering property. Although a certain amount of coke was produced, mainly with disorder filamentous carbon of basegrowth, the Ni/SBA-15 prepared by homogeneous precipitation exhibited excellent catalytic activity and stability.

Excessive mechanical strain accelerates intervertebral disc degeneration by disrupting intrinsic circadian rhythm

Ding Sheng-Long,Zhang Tai-Wei,Zhang Qi-Chen,Ding Wang,Li Ze-Fang,Han Guan-Jie,Bai Jin-Song,Li Xi-Lei,Dong Jian,Wang Hui-Ren,Jiang Li-Bo 생화학분자생물학회 2021 Experimental and molecular medicine Vol.53 No.-

Night shift workers with disordered rhythmic mechanical loading are more prone to intervertebral disc degeneration (IDD). Our results showed that circadian rhythm (CR) was dampened in degenerated and aged NP cells. Long-term environmental CR disruption promoted IDD in rats. Excessive mechanical strain disrupted the CR and inhibited the expression of core clock proteins. The inhibitory effect of mechanical loading on the expression of extracellular matrix genes could be reversed by BMAL1 overexpression in NP cells. The Rho/ROCK pathway was demonstrated to mediate the effect of mechanical stimulation on CR. Prolonged mechanical loading for 12 months affected intrinsic CR genes and induced IDD in a model of upright posture in a normal environment. Unexpectedly, mechanical loading further accelerated the IDD in an Light-Dark (LD) cycle-disrupted environment. These results indicated that intrinsic CR disruption might be a mechanism involved in overloading-induced IDD and a potential drug target for night shift workers.

Synchronous immobilization and conversion of polysulfides on a VO₂-VN binary host targeting high sulfur load Li-S batteries

Song, Yingze,Zhao, Wen,Kong, Long,Zhang, Li,Zhu, Xingyu,Shao, Yuanlong,Ding, Feng,Zhang, Qiang,Sun, Jingyu,Liu, Zhongfan The Royal Society of Chemistry 2018 ENERGY AND ENVIRONMENTAL SCIENCE Vol.11 No.9

<P>Lithium-sulfur (Li-S) batteries are deemed as one of the most promising next-generation energy storage systems. However, their practical application is hindered by existing drawbacks such as poor cycling life and low Coulombic efficiency due to the shuttle effect of lithium polysulfides (LiPSs). We herein present an <I>in situ</I> constructed VO2-VN binary host which combines the merits of ultrafast anchoring (VO2) with electronic conducting (VN) to accomplish smooth immobilization-diffusion-conversion of LiPSs. Such synchronous advantages have effectively alleviated the polysulfide shuttling, promoted the redox kinetics, and hence improved the electrochemical performance of Li-S batteries. As a result, the sulfur cathode based on the VO2-VN/graphene host exhibited an impressive rate capability with ∼1105 and 935 mA h g<SUP>−1</SUP> at 1C and 2C, respectively, and maintained long-term cyclability with a low capacity decay of 0.06% per cycle within 800 cycles at 2C. More remarkably, favorable cyclic stability can be attained with a high sulfur loading (13.2 mg cm<SUP>−2</SUP>). Even at an elevated temperature (50 °C), the cathodes still delivered superior rate capacity. Our work emphasizes the importance of immobilization-diffusion-conversion of LiPSs toward the rational design of high-load and long-life Li-S batteries.</P>

Roles of NMDA NR2B Subtype Receptor in Prefrontal Long-Term Potentiation and Contextual Fear Memory

Zhao, Ming-Gao,Toyoda, Hiroki,Lee, Yong-Seok,Wu, Long-Jun,Ko, Shanelle W.,Zhang, Xue-Han,Jia, Yongheng,Shum, Fanny,Xu, Hui,Li, Bao-Ming,Kaang, Bong-Kiun,Zhuo, Min Elsevier 2005 Neuron Vol.47 No.6

<P><B>Summary</B></P><P>Cortical plasticity is thought to be important for the establishment, consolidation, and retrieval of permanent memory. Hippocampal long-term potentiation (LTP), a cellular mechanism of learning and memory, requires the activation of glutamate N-methyl-D-aspartate (NMDA) receptors. In particular, it has been suggested that NR2A-containing NMDA receptors are involved in LTP induction, whereas NR2B-containing receptors are involved in LTD induction in the hippocampus. However, LTP in the prefrontal cortex is less well characterized than in the hippocampus. Here we report that the activation of the NR2B and NR2A subunits of the NMDA receptor is critical for the induction of cingulate LTP, regardless of the induction protocol. Furthermore, pharmacological or genetic blockade of the NR2B subunit in the cingulate cortex impaired the formation of early contextual fear memory. Our results demonstrate that the NR2B subunit of the NMDA receptor in the prefrontal cortex is critically involved in both LTP and contextual memory.</P>

Targeting treatment of bladder cancer using PTK7 aptamer-gemcitabine conjugate

Xiang Wei,Peng Yongbo,Zeng Hongliang,Yu Chunping,Zhang Qun,Liu Biao,Liu Jiahao,Hu Xing,Wei Wensu,Deng Minhua,Wang Ning,Liu Xuewen,Xie Jianfei,Hou Weibin,Tang Jin,Long Zhi,Wang Long,Liu Jianye 한국생체재료학회 2023 생체재료학회지 Vol.27 No.00

Gemcitabine (GEM) is one of the first-line chemotherapies for bladder cancer (BC), but the GEMs cannot recognize cancer cells and have a low long-term response rate and high recurrence rate with side effects during the treatment of BC. Targeted transport of GEMs to mediate cytotoxicity to tumor and avoid the systemic side effects remains a challenge in the treatment of BC.Based on a firstly confirmed biomarker in BC-protein tyrosine kinase 7 (PTK7), which is overexpressed on the cell membrane surface in BC cells, a novel targeting system protein tyrosine kinase 7 aptamer-Gemcitabine conjugate (PTK7-GEMs) was designed and synthesized using a specific PTK7 aptamer and GEM through auto-synthesis method to deliver GEM against BC. In addition, the antitumor effects and safety evaluation of PTK7-GEMs was assessed with a series of in vitro and in vivo assays.PTK7-GEMs can specifically bind and enter to BC cells dependent on the expression levels of PTK7 and via the macropinocytosis pathway, which induced cytotoxicity after GEM cleavage from PTK7-GEMs respond to the intracellular phosphatase. Moreover, PTK7-GEMs showed stronger anti-tumor efficacy and excellent biosafety in three types of tumor xenograft mice models.These results demonstrated that PTK7-GEMs is a successful targeted aptamer-drug conjugates strategy (APDCs) to treat BC, which will provide new directions for the precision treatment of BC in the field of biomarker-oriented tumor targeted therapy.

Liquid Chromatography-Tandem Mass Spectrometry-Based Metabolomics Analysis of Indigo Naturalis Treatment of Ulcerative Colitis in Mice

Zheng Wang,Yanni Liang,Anqi Fan,Bao-Long Hou,Zhishu Tang,Ting Wang,Dongbo Zhang 한국식품영양과학회 2023 Journal of medicinal food Vol.26 No.12

Ulcerative colitis (UC), often known as UC, is an inflammatory disease of the intestines that has frequent andlong-lasting flare-ups. It is unknown precisely how the traditional Chinese drug Indigo Naturalis (IN) heals inflammatorybowel disease, despite its long-standing use in China and Japan. Finding new metabolite biomarkers linked to UC couldimprove our understanding of the disease, speed up the diagnostic process, and provide insight into how certain drugs work totreat the condition. Our work is designed to use a metabolomic method to analyze potential alterations in endogenoussubstances and their impact on metabolic pathways in a mouse model of UC. To determine which biomarkers and metabolismsare more frequently connected with IN’s effects on UC, liquid chromatography-tandem mass spectrometry analysis ofthe serum metabolomics of UC mice and normal mice was performed. The outcomes demonstrated that IN boosted the healthof UC mice and reduced the severity of their metabolic dysfunction. In the UC model, it was also found that IN changed theway 17 biomarkers and 3 metabolisms functioned.

Nanoparticle additions for enhanced flux pinning in YBCO HTS films

N.M. Strickland,N.J. Long,E.F. Talantsev,P. Hoefakker,J.A. Xia,M.W. Rupich,W. Zhang,X. Li,T. Kodenkandath,Y. Huang 한국물리학회 2008 Current Applied Physics Vol.8 No.3,4

We describe a method for forming a nanoparticle dispersion in YBa₂Cu₃O7 superconducting lms grown by metal-organic depositionon RABiTS substrates. Two separate precursor modications have been shown by transmission electron microscopy to give nanopar-ticles of (Y,Dy)₂O₃ and BaZrO₃ with size distributions of 10-50 nm and 10-25 nm, respectively and that are well dispersed in the lm.These particles are eective ux pinning centers and enhance the transport critical current by up to 100% at 77 K for a magnetic eld of 1.5 T applied perpendicular to the tape. The processing required to grow these lms is not greatly altered from that of unmodied YBCO and can be readily transferred to continuous processing of long-length wires.