Effect of Heat Treatment on Microstructure and Mechanical Properties of Mg-10Li-3Al-3Zn-0.22Si Alloy

Yazhao Shen,Defu Li,Shengli Guo,Jiangtao Guo 대한금속·재료학회 2022 METALS AND MATERIALS International Vol.28 No.10

The microstructure evolution and mechanical properties of as-extruded Mg-10Li-3Al-3Zn-0.22Si during heat treatment from473 to 673 K were investigated in this paper, and then the strengthening mechanism and fracture behavior of the studied alloywas also analyzed. Experimental results show that the matrix of as-extruded Mg-10Li-3Al-3Zn-0.22Si alloy mainly consistsof α-Mg and β-Li, and dispersive granular phases are AlLi and Li2MgAl. Mg2Siphase shows banded distribution alongextrusion direction. The morphology of α-Mg is from long strip to nearly spherical block at 573 K. The α-Mg reprecipitatesfrom β-Li matrix in the orientation relationship: (0001) α-Mg // (110) β-Li, [11 −2 0] α-Mg // [1 −1 0] β-Li at 623 K. While theAl-rich granular phase is decomposed and dissolve into the gradually, and then AlLi increase again at 673 K, which may becaused by the dissolution at high temperature and precipitation during air cooling in heat treatment. Besides, the solid solutionand dispersion strengthening enhances the strength of alloy after heat treatment. After heat-treated at 573 K for 1 h and thenair cooling, alloy presents excellent mechanical properties with the ultimate tensile strength of 253 ± 3 MPa and elongationof 27 ± 3%, respectively. Compared with the extruded state, ultimate tensile strength of alloy can be increased by about 49%.

한국인 및 중국 한족 정신분열병 환자의 5-HT2A 수용체 유전자 -1438A/G 다형성

이장호,이광철,이승부,오용인,최영근,조아랑,정주호,장환일 大韓神經精神醫學會 2005 신경정신의학 Vol.44 No.1

Objectives : The purpose of the present study was to investigate the association between -1438A/G polymorphism of 5-HT2A receptor gene and schizophrenia in Korean and Han Chinese population. Methods : A sample of 184 Korean patients with schizophrenia and 96 Korean healthy normal controls and 96 Han Chinese patients with schizophrenia and 96 Han-Chinese healthy normal controls were genotyped for a single nucleotide polymorphism with in 5-HT2A receptor gene (promoter region, A-1438G) by Msp I Resthction Fragment Length Polymorphism (RFLP). Results : There was no difference in allelic frequencies and genotype frequencies of -1438A/G polymorphism between Korean schizophrenics and controls (p=0.13) and Han Chinese schizophrenics and controls (p=0.40). Also, -1438A/G Poly-morphism did not show ethnical difference between Korean and Han Chinese controls. The Scale for the Assessment of Negative Symptoms (SANS) scores showed no significant differences between genotypes of -1438A/G polymorphism in both of Korean and Han Chinese schizophrenics. Conclusion : These results suggest that -1438A/G polymorphism of the 5-HT2A receptor gene is not causally related to the development of schizophrenia in Korean and Han Chinese population, and there no ethnic difference between Korean and Han Chinese population.

Cloning and Characterization of a Na+/H+ Antiporter Gene of the Moderately Halophilic Bacterium Halobacillus aidingensis AD-6T

Ya Jie Zou,Li Fu Yang,Lei Wang,Su Sheng Yang 한국미생물학회 2008 The journal of microbiology Vol.46 No.4

A gene encoding a Na+/H+ antiporter was obtained from the genome of Halobacillus aidingensis AD-6T, which was sequenced and designated as nhaH. The deduced amino acid sequence of the gene was 91% identical to the NhaH of H. dabanensis, and shared 54% identity with the NhaG of Bacillus subtilis. The cloned gene enable the Escherichia coli KNabc cell, which lack all of the major Na+/H+ antiporters, to grow in medium containing 0.2 M NaCl or 10 mM LiCl. The nhaH gene was predicted to encode a 43.5 kDa protein (403 amino acid residues) with 11 putative transmembrane regions. Everted membrane vesicles prepared from E. coli KNabc cells carrying NhaH exhibited Na+/H+ as well as Li+/H+ antiporter activity, which was pH-dependent with the highest activity at pH 8.0, and no K+ /H+ antiporter activity was detected. The deletion of hydrophilic C-terminal amino acid residues showed that the short C-terminal tail was vital for Na+/H+ antiporter activity.

Purification and Characterization of Extracellular Inulinase from a Marine Yeast Pichia guilliermondii and Inulin Hydrolysis by the Purified Inulinase

Fang Gong,Tong Zhang,Jun Sheng,Jing Li,Xianghong Wang,Zhenming Chi 한국생물공학회 2008 Biotechnology and Bioprocess Engineering Vol.13 No.5

The extracellular inulinase of the marine yeast Pichia guilliermondii strain 1 was purified to homogeneity resulting in a 7.2-fold increase in specific inulinase activity. The molecular mass of the purified enzyme was estimated to be 50.0 kDa. The op-timal pH and temperature for the purified enzyme were 6.0 and 60C, respectively. The enzyme was activated by Mn²+, Ca²+, K+, Li+, Na+, Fe³+, Fe²+, Cu²+, and Co²+, but Mg²+, Hg²+, and Ag+ inhibited activity. The enzyme was strongly inhibited by phenylmethanesulphonyl fluoride (PMSF), iodoacetic acid, EDTA, and 1, 10-phenanthroline. The Km and Vmax values of the purified inulinase for inulin were 21.1 mg/mL and 0.08 mg/min, respectively. A large number of monosaccharides were de-tected after the hydrolysis of inulin. The deduced protein sequence from the cloned P. guilliermondii strain 1 inulinase gene contained the consensus motifs R-D-P-K-V-F-W-H and W-M-N-D-P-N-G, which are conserved among the inulinases from other microorganisms.

Preparation of lithium-doped NaV6O15 thin film cathodes with high cycling performance in SIBs

Xu Hai-Yan,Ruan Jun Hai,Liu Fang Lin,Li Dong-Cai,Zhang Feng-Jun,Wang Ai-Guo,Sun Dao-Sheng,오원춘 한국세라믹학회 2022 한국세라믹학회지 Vol.59 No.3

Lithium ions-doped NaV6O15 thin films have been prepared using a simple low temperature liquid phase deposition method and subsequent annealing process. X-ray diffraction (XRD), Fourier transform infrared spectrometer (FTIR), scanning elec- tron microscopy (SEM), and photoelectron spectroscopy (XPS) have been used to study the structural and physicochemical characteristics of the NaV6O15 film. The films were grown on the FTO conductive glass and used directly as an electrode of sodium ion batteries. The prepared lithium ions-doped NaV6O15 thin film electrodes showed an excellent cycling stability and discharge capacity, which may be attributed to the stability of the Li+ embedded into the gap between the V–O layers to maintain the structure and its stable β-phase structure transformed after the first cycle. The cycling stability greatly improved with increasing annealing temperature, while the discharge capacity decreased. The capacities of the film electrodes annealed at 400 °C and 450 °C maintained above 97% after 100 cycles. The lithium-doped NaV6O15 underwent a phase transition dur- ing the first charge/discharge cycle. The new transformed phase has perfect crystal structure stability undergoing insertion and deinsertion of Na+. Therefore, the lithium-doped NaV6O15 thin film possesses good cycling stability and is expected to be a promising thin film cathode for sodium-ion batteries.

Electrochemical Cr(VI) reduction using a sacrificial Fe anode: Impacts of solution chemistry and stoichiometry

Chuang, Sheng-Ming,Ya, Vinh,Feng, Chiao-Lin,Lee, Shou-Jen,Choo, Kwang-Ho,Li, Chi-Wang Elsevier 2018 Separation and purification technology Vol.191 No.-

<P><B>Abstract</B></P> <P>A systematic investigation of Cr(VI) reduction using electrochemical reduction revealed that the Cr(VI) reduction was extremely fast with reaction kinetics limited by the anodic generation of Fe(II). The Cr(VI) reduction rate increased with decreasing pH at the initial stage of reaction but the time to reach complete Cr(VI) reduction is pH independent. The amount of Fe(II) generated per mole of Cr(VI) reduced was calculated and compared with the stoichiometric value, i.e., 3mole of Fe(II) needed per mole of Cr(VI) reduced. The values are 11.1% higher than the stoichiometric value for pH 7 and 9, but are 32.0% less for pH 3 and 5. The spontaneous reduction of Cr(VI) by Fe<SUP>0</SUP> and adsorption of Cr(VI) to Fe(OH)<SUB>3</SUB> precipitates might contribute the additional Cr(VI) removal. Effect of DO was investigated under various mixing schemes. Under N<SUB>2</SUB> purging, Fe(II) generated for one mole of Cr(VI) reduced is 3.67% higher than the stoichiometric value, while mechanic mixing and aeration mixing show 15% and 19%, respectively, higher than stoichiometric value, indicating that DO does impact Cr(VI) reduction. The electrochemical Cr(VI) reduction process was also employed to treat electroplating wastewater with and without pH pre-adjustment, achieving 100% total Cr and Ni removal for both cases. ORP can be used as a controlling parameter when electrochemical reduction is implemented for Cr(VI) reduction.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Effect of current on Cr(VI) reduction under same current density was studied. </LI> <LI> Effects of initial and fixed pH on Cr(VI) reduction were investigated. </LI> <LI> Effect of DO on Cr(VI) reduction was explored. </LI> <LI> Electrochemical reduction was applied for treating electroplating wastewater. </LI> <LI> ORP is an ideal parameter for controlling electrochemical Cr(VI) reduction. </LI> </UL> </P>

Assessing the removal of organic micropollutants by a novel baffled osmotic membrane bioreactor-microfiltration hybrid system

Pathak, Nirenkumar,Li, Sheng,Kim, Youngjin,Chekli, Laura,Phuntsho, Sherub,Jang, Am,Ghaffour, Noreddine,Leiknes, TorOve,Shon, Ho Kyong Elsevier 2018 Bioresource technology Vol.262 No.-

<P><B>Abstract</B></P> <P>A novel approach was employed to study removal of organic micropollutants (OMPs) in a baffled osmotic membrane bioreactor-microfiltration (OMBR-MF) hybrid system under oxicanoxic conditions. The performance of OMBR-MF system was examined employing three different draw solutes (DS), and three model OMPs. The highest forward osmosis (FO) membrane rejection was attained with atenolol (100%) due to its higher molar mass and positive charge. With inorganic DS caffeine (94–100%) revealed highest removal followed by atenolol (89–96%) and atrazine (16–40%) respectively. All three OMPs exhibited higher removal with organic DS as compared to inorganic DS. Significant anoxic removal was observed for atrazine under very different redox conditions with extended anoxic cycle time. This can be linked with possible development of different microbial consortia responsible for diverse enzymes secretion. Overall, the OMBR-MF process showed effective removal of total organic carbon (98%) and nutrients (phosphate 97% and total nitrogen 85%), respectively.</P> <P><B>Highlights</B></P> <P> <UL> <LI> A hybrid OMBR-MF examined for OMPs and nutrient removal from simulated sewage. </LI> <LI> Performance of inorganic and organic draw solutes in OMBR-MF system assessed. </LI> <LI> Baffled OMBR-MF achieved high removal for nutrient and OMPs. </LI> <LI> Persistent OMP like atrazine exhibited high anoxic removal compared to oxic. </LI> <LI> Atenolol showed highest forward osmosis rejection due to high molar mass. </LI> <LI> Large microbial flocs contributed to lower membrane fouling propensity. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Alantolactone selectively suppresses STAT3 activation and exhibits potent anticancer activity in MDA-MB-231 cells

Chun, Jaemoo,Li, Rui-Juan,Cheng, Mao-Sheng,Kim, Yeong Shik Elsevier 2015 Cancer letters Vol.357 No.1

<P><B>Abstract</B></P> <P>The important goal of cancer drug discovery is to develop therapeutic agents that are effective, safe, and affordable. In the present study, we demonstrated that alantolactone, which is a sesquiterpene lactone, has potential activity against triple-negative breast cancer MDA-MB-231 cells by suppressing the signal transducer and activator of transcription 3 (STAT3) signaling pathway. Alantolactone effectively suppressed both constitutive and inducible STAT3 activation at tyrosine 705. Alantolactone decreased STAT3 translocation to the nucleus, its DNA-binding, and STAT3 target gene expression. Alantolactone significantly inhibits STAT3 activation with a marginal effect on MAPKs and on NF-κB transcription; however, this effect is not mediated by inhibiting STAT3 upstream kinases. Although SHP-1, SHP-2, and PTEN, which are protein tyrosine phosphatases (PTPs), were not affected by alantolactone, the treatment with a PTP inhibitor reversed the alantolactone-induced suppression of STAT3 activation, indicating that PTP plays an important role in the action of alantolactone. Finally, alantolactone treatment resulted in the inhibition of migration, invasion, adhesion, and colony formation. The <I>in vivo</I> administration of alantolactone inhibited the growth of human breast xenograft tumors. These results provide preclinical evidence to continue the development of alantolactone as a STAT3 inhibitor and as a potential therapeutic agent against breast cancer.</P> <P><B>Highlights</B></P> <P> <UL> <LI> STAT3 is a transcription factor that is a potent regulator of tumorigenesis. </LI> <LI> Alantolactone suppresses constitutive and inducible STAT3 tyrosine phosphorylation. </LI> <LI> Alantolactone inhibits NF-κB translocation to the nucleus. </LI> <LI> Alantolactone inhibits cell migration, invasion, adhesion, and colony formation. </LI> <LI> Alantolactone inhibits the tumor growth of MDA-MB-231 xenografts in mice. </LI> </UL> </P>

Microstructure evolution and enhanced vacuum tribological performance of Ni-doped WS₂ composite coating

Xu, Shu-Sheng,Weng, Li-Jun,Liu, Yu-Zhen,Kang, Kyeong-Hee,Kim, Chang-Lae,Kim, Dae-Eun Elsevier Sequoia 2017 Surface & coatings technology Vol.325 No.-

<P><B>Abstract</B></P> <P>Ni-doped WS<SUB>2</SUB> composite coatings with various Ni contents were co-deposited using a radio frequency sputtering system on silicon wafer and AISI 440C stainless steel substrates. The microstructural characteristics of the WS<SUB>2</SUB>-Ni composite coatings and their tribological properties in vacuum were assessed. During introduction of Ni dopant in the WS<SUB>2</SUB>-Ni composite coating the sulfur/tungsten (S/W) ratio in the coating increased due to reduced preferential resputtering of sulfur atoms in the growing coating. The microstructure of the WS<SUB>2</SUB>-Ni composite coating varied from a fine columnar structure for Ni content equal to or less than 7.7at.% to a featureless structure as the Ni content increased further. The Ni dopant inhibited the growth of the coarse columnar WS<SUB>2</SUB> platelets which was accompanied by nanocrystallization and amorphization of the composite coating structure. WS<SUB>2</SUB>-Ni composite coatings with fine columnar structure exhibited relatively low hardness but showed a high tendency to form a lubricating transfer layer. It also demonstrated low brittleness and prolonged wear life in vacuum condition compared to coatings with dense featureless structure. The variation in tribological performance between the composite coatings resulted from the different wear mechanisms associated with their distinct microstructures.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Microstructure of WS<SUB>2</SUB> coating was modified by incorporating Ni as a dopant. </LI> <LI> The introduction of Ni increased the S/W ratio of the WS<SUB>2</SUB> composite coating. </LI> <LI> High Ni content in the WS<SUB>2</SUB> coating led to high brittleness and low wear resistance. </LI> <LI> WS<SUB>2</SUB>–5at.% Ni coating showed 5 times longer wear life than pure WS<SUB>2</SUB> film in vacuum. </LI> <LI> Superior tribological properties were attributed to transfer layer and high hardness. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Separation and purification of three, four, and five carbon diamines from fermentation broth

Lee, Jong An,Ahn, Jung Ho,Kim, Inho,Li, Sheng,Lee, Sang Yup Elsevier 2019 Chemical engineering science Vol.196 No.-

<P><B>Abstract</B></P> <P>1,3-diaminopropane (1,3-DAP), 1,4-diaminobutane (1,4-DAB), and 1,5-diaminopentane (1,5-DAP) are important chemicals due to their wide industrial use including agrochemicals, pharmaceuticals, surfactants, and building blocks for nylon synthesis. Over the last decade, several studies on bio-based production of diamines by metabolically engineered microorganisms have been published. However, development of efficient methods for the recovery of 1,3-DAP, 1,4-DAB, and 1,5-DAP from fermentation broth has not been reported. In this study, an efficient process for the separation and purification of 1,3-DAP, 1,4-DAB, and 1,5-DAP from fermentation broth without using highly flammable or toxic solvents was developed. The optimal process for the recovery and purification of these diamines from fermentation broth comprises several unit operations including removal of cell debris, decolorization of fermentation broth, product concentration, deprotonation of diamines, product separation, and final polishing to obtain pure 1,3-DAP, 1,4-DAB, and 1,5-DAP with yields of 87 ± 3%, 86 ± 4%, and 81 ± 2%, respectively. Process development for the recovery and purification of fermentatively produced diamines reported here is expected to facilitate synthesis of bio-based nylons. Furthermore, the strategy reported here could be similarly applicable in developing downstream processes to recover and purify other diamines and related chemicals from fermentation broth.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Developed purification process for 3–5 carbon diamines from fermentation broth. </LI> <LI> Diamines recovered and purified from fermentation broth with yields of 80–90%. </LI> <LI> Three-step evaporation process coupled with deprotonation was effective. </LI> <LI> This purification process does not use highly flammable and toxic solvents. </LI> <LI> Diamines purified this way can be used for manufacturing bio-based nylons. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>