Effects of Quenching Methods and Aging Processes on the Crushing Properties and Microstructure of Al–Zn–Mg Alloy Thin-Walled Square Extrusions

Hui Guo,Jin Zhang,Cheng Wang,Yun‑lai Deng 대한금속·재료학회 2022 METALS AND MATERIALS International Vol.28 No.8

In this study, the effects of different (online quenching and offline quenching) quenching methods and aging processes (T6and T73) on the crashworthiness and microstructural evolution of three Al–Zn–Mg alloys (G1–G3) were studied by conductingtensile test and axial compression tests at room temperature, combined with optical metallography, electron back scattereddiffraction, and transmission electron microscopy microstructural observations. The obtained results revealed that thecrushing properties of three different Al–Zn–Mg alloys subjected to different quenching methods and aging processes weresignificantly different. Their crushing energy absorption of are ranked as follows: G1 > G3 > G2. The highest total energyabsorption gap (between T6 and T73) is the G1 alloy, and the lowest one is the G3 alloy. The largest total energy absorptiongap between the two quenching methods is the G3 alloy, and the smallest one is the G1 alloy. The G2 alloy with the largesttotal amount of Zn + Mg has the highest number density of matrix precipitates, the largest precipitate gap (between T6 andT73) and the smallest precipitate gap between the two quenching methods. The G3 alloy with the largest Zn/Mg ratio hasthe smallest number density of matrix precipitates, the minimum precipitation gap (between T6 and T73) and the maximumprecipitation gap between the two quenching methods. The G1 alloy with the lowest Zn/Mg ratio has the smallest size ofgrain boundary precipitates and PFZ width, while their largest values are obtained for the G3 alloy with the maximum Zn/Mg ratio. As a crushing resistant structural material, the crushing properties is improved without reducing the strength. Theratio of Zn/Mg should be controlled within the range of 4.57–6.15, while the total amount of Zn + Mg should be controlledwithin the range of 6.18–7.01.

Production of a Recombinant Laccase from Pichia pastoris and Biodegradation of Chlorpyrifos in a Laccase/Vanillin System

( Hui fang Xie ),( Qi Li ),( Min Min Wang ),( Lin Guo Zhao ) 한국미생물 · 생명공학회 2013 Journal of microbiology and biotechnology Vol.23 No.6

The recombinant strain P. pastoris GS115-lccC was used to produce laccase with high activity. Factors influencing laccase expression, such as pH, methanol concentration, copper concentration, peptone concentration, shaker rotate speed, and medium volume were investigated. Under the optimal conditions, laccase activity reached 12,344 U/L on day 15. The recombinant enzyme was purified by precipitating and dialyzing to electrophoretic homogeneity, and was estimated to have a molecular mass of about 58 kDa. When guaiacol was the substrate, the laccase showed the highest activity at pH 5.0 and was stable when the pH was 4.5~6.0. The optimal temperature for the laccase to oxidize guaiacol was 60℃, but it was not stable at high temperature. The enzyme could remain stable at 30℃ for 5 days. The recombinant laccase was used to degrade chlorpyrifos in several laccase/mediator systems. Among three synthetic mediators (ABTS, HBT, VA) and three natural mediators (vanillin, 2,6-DMP, and guaiacol), vanillin showed the most enhancement on degradation of chlorpyrifos. Both laccase and vanillin were responsible for the degradation of chlorpyrifos. A higher dosage of vanillin may promote a higher level of degradation of chlorpyrifos, and the 2-step addition of vanillin led to 98% chlorpyrifos degradation. The degradation of chlorpyrifos was faster in the L/V system (kobs = 0.151) than that in the buffer solution (kobs = 0.028).

MUC16 facilitates cervical cancer progression via JAK2/STAT3 phosphorylation‑mediated cyclooxygenase‑2 expression

Hui Shen,Meng Guo,Lu Wang,Xinyue Cui 한국유전학회 2020 Genes & Genomics Vol.42 No.2

Objectives MUC16 (mucin 16, also known as CA-125, cancer antigen 125, carcinoma antigen 125, or carbohydrate antigen 125) has been predicted as tumor biomarker for therapy. We determined to investigate effects and regulatory mechanism of MUC16 on cervical tumorigenesis. Methods Expression levels of MUC16 in cervical cancer cell lines was analyzed via qRT-PCR (quantitative real-time polymerase chain reaction). Knockdown of MUC16 was conducted via shRNA (Short hairpin RNA) transfection. MTT and colony formation assays were used to investigate effect of MUC16 on cell proliferation. Wound healing assay was utilized to detect migration and transwell assay to detect invasion. The underlying mechanism was demonstrated via western blot analysis. Results MUC16 was elevated in cervical cancer cell lines. MUC16 knockdown inhibited cell proliferation, invasion and migration. Gain- and loss-of functional assays revealed that over-expression of MUC16 activated Janus Kinase 2 (JAK2)/ signal transducer and activator of transcription 3 (STAT3) via phosphorylation, thus facilitating cyclooxygenase-2 (COX-2) expression, while knockdown of MUC16 demonstrated the reverse effect on JAK2/STAT3 activation and COX-2 expression. Moreover, inhibition of JAK2/STAT3 attenuated the regulation of MUC16 on COX-2. Conclusions MUC16 enhanced proliferation and invasion of cervical cancer cells via JAK2/STAT3 phosphorylation-mediated cyclooxygenase-2 expression, suggesting the potential therapeutic target ability of MUC16 to treat cervical cancer.

Dichloromethane fraction of <i>Asiasarum heterotropoides</i> induces S phase arrest and apoptosis in KB oral epithelial carcinoma cells

Guo, Hui-Fang,Wang, Myeong-Hyeon EDITIONS SCIENTIFIQUES ELSEVIER 2017 BIOMEDICINE AND PHARMACOTHERAPY Vol.89 No.-

<P><B>Abstract</B></P> <P>We investigated the anti-cancer activity and molecular mechanism of dichloromethane fraction (DCM-AH) of ethanolic extract from <I>Asiasarum heterotropoides</I> radix. The KB cancer cells and HEK293 cells were exposed to DCM-AH in the same condition and found the cell viability of KB cell decreased significantly while the HEK293 cell showed a slight reduction. This finding suggested DCM-AH performed an anti-cancer activity in a dose and time dependent manner. As evidence for the DCM-AH inhibited the proliferation via modulating the cell cycle, flow cytometry and Western blot were conducted, it induced cell S phase arrest by upregulation of p21, p53, and cyclin E1 along with the downregulation of cyclin A2 and D1. Besides, it inhibited the proliferation of KB cells by triggering apoptosis, the stimulation of 4μg/mL DCM-AH obviously induced DNA condensation with an apoptotic rate of 31.2%. Undergoing mechanism was detected by Western blot, the upregulated expression of Bax, cleaved caspase-3, and -9 meantime downregulation of Bcl-2 explained it induced apoptosis by the intrinsic pathway.</P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Highly Chemo- and Regioselective Reaction of Hydroxybenzenes in Acidic Ionic Liquid

Hui Guo,Yu Wei Zhuang,Jian Cao,Guo Bao Zhang 대한화학회 2013 Bulletin of the Korean Chemical Society Vol.34 No.9

Highly chemo- and regioselective reaction of hydroxybenzenes with α,β-unsaturated compounds in acidic ionic liquid l-butyl-3-methylimidazolium hydrogen sulphate ([BMIM]HSO4) was reported for the first time. A series of oxa-Michael adducts and Friedel-Crafts alkylated products were synthesized with good yields. The acidic ionic liquid could be easily recycled for at least 5 times with only minor loss in activity.

Highly Chemo- and Regioselective Reaction of Hydroxybenzenes in Acidic Ionic Liquid

Guo, Hui,Zhuang, Yu Wei,Cao, Jian,Zhang, Guo Bao Korean Chemical Society 2013 Bulletin of the Korean Chemical Society Vol.34 No.9

Highly chemo- and regioselective reaction of hydroxybenzenes with ${\alpha},{\beta}$-unsaturated compounds in acidic ionic liquid l-butyl-3-methylimidazolium hydrogen sulphate ([BMIM]HSO4) was reported for the first time. A series of oxa-Michael adducts and Friedel-Crafts alkylated products were synthesized with good yields. The acidic ionic liquid could be easily recycled for at least 5 times with only minor loss in activity.

Simultaneous Single-Position Lateral Lumbar Interbody Fusion Surgery and Unilateral Percutaneous Pedicle Screw Fixation for Spondylolisthesis

Hui Lv,Yu Sheng Yang,Jian Hong Zhou,Yuan Guo,Hui Chen,Fei Luo,Jian Zhong Xu,Zhong Rong Zhang,Ze Hua Zhang 대한척추신경외과학회 2023 Neurospine Vol.20 No.3

Objective: To evaluate the clinical and radiological efficacy of a combine of lateral single screw-rod and unilateral percutaneous pedicle screw fixation (LSUP) for lateral lumbar interbody fusion (LLIF) in the treatment of spondylolisthesis. Methods: Sixty-two consecutive patients with lumbar spondylolisthesis who underwent minimally invasive (MIS)-TLIF with bilateral pedicle screw (BPS) or LLIF-LSUP were retrospectively studied. Segmental lordosis angle (SLA), lumbar lordosis angle (LLA), disc height (DH), slipping percentage, the cross-sectional areas (CSA) of the thecal sac, screw placement accuracy, fusion rate and foraminal height (FH) were used to evaluate radiographic changes postoperatively. Visual analogue scale (VAS) and Oswestry Disability Index (ODI) were used to evaluate the clinical efficacy. Results: Patients who underwent LLIF-LSUP showed shorter operating time, less length of hospital stay and lower blood loss than MIS-TLIF. No statistical difference was found between the 2 groups in screw placement accuracy, overall complications, VAS, and ODI. Compared with MIS-TLIF-BPS, LLIF-LSUP had a significant improvement in sagittal parameters including DH, FH, LLA, and SLA. The CSA of MIS-TLIF-BPS was significantly increased than that of LLIF-LSUP. The fusion rate of LLIF-LSUP was significantly higher than that of MIS-TLIF-BPS at the follow-up of 3 months postoperatively, but there was no statistical difference between the 2 groups at the follow-up of 6 months, 9 months, and 12 months. Conclusion: The overall clinical outcomes and complications of LLIF-LSUP were comparable to that of MIS-TLIF-BPS in this series. Compared with MIS-TLIF-BPS, LLIF-LSUP for lumbar spondylolisthesis represents a significantly shorter operating time, hospital stay and lower blood loss, and demonstrates better radiological outcomes to maintain lumbar lordosis, and reveal an overwhelming superiority in the early fusion rate.

Long-term Deflection Test and Theoretical Analysis on Cracked Prestressed Concrete Box Beams

Guo Hui Cao,Sheng Zhang,Wang Zhang,Xi Rong Peng 대한토목학회 2018 KSCE JOURNAL OF CIVIL ENGINEERING Vol.22 No.2

A long-term deflection test is performed for 470 days on two simply supported prestressed concrete box beams under sustained uniform load. The deflection growth rules of the box beams under both cracked and uncracked states are studied. The measured longterm deflection of the cracked beam is 18.4% larger than that of the uncracked beam, whereas the deflection growth coefficient of the cracked beam is 65.3% that of the uncracked beam. The larger long-term deflection of the cracked beam is mainly attributed to the huge value of the instantaneous deflection caused by the crack. Then, the cracks lead to the release of concrete stress, thereby reducing the creep effect. For the uncracked beam, the influences of concrete shrinkage, creep, and prestress loss on the long-term mechanical behavior of components are considered, and then deflection is predicted using the blended method based on the ageadjusted modulus method, the prestressed equivalent load method, and the calculation method for prestress loss. Results show that the theoretical and measured values are in good agreement. For the cracked beam, the crack influence coefficient is introduced to revise its effective elastic modulus by considering the influence of cracks on the long-term deflection of the cracked beam. Then, a formula for calculating the long-term deflection of cracked beams that considers stiffness reduction for instantaneous deflection correction is proposed. The formula exhibits high precision in calculating and analyzing the long-term deflection of the cracked beam. The deviation between the calculated and measured values is within 10%.

ACOS5 is Required for Primexine Formation and Exine Pattern Formation During Microsporogenesis in Arabidopsis

Hui-hui Xie,Lin Chen,Fa-qing Xu,Wan-sheng Guo,Shui Wang,Zhong-Nan Yang,Sen Zhang 한국식물학회 2017 Journal of Plant Biology Vol.60 No.4

Pollen exine, mainly composed of sporopollenin,plays important roles during microspore development. It hasbeen reported that Acyl-CoA Synthetase5 (ACOS5) is requiredfor sporopollenin biosynthesis in Arabidopsis. Here we showthat ACOS5 is essential for primexine formation duringArabidopsis microspore development. Through genetic screen,we identified a point mutation of ACOS5 allele, acos5-2,showing abnormal microspore development. Its microsporeswere degenerated and aborted after released from the tetrads. Transmission electron microscopy showed that primexineformation was reduced in acos5-2 mutant as compared tothat of the wild-type. Consequently, sporopollenin wasaggregated and randomly deposited on the microspores. Insitu hybridization indicated that the key regulators of tapetumdevelopment, DYT1 and TDF1, are required for the expressionof ACOS5 in tapetum. Furthermore, the GUS reporter showedthat the 593-bp promoter sequence was sufficient for theexpression of ACOS5 in the anther. Our data provide evidencethat ACOS5 is required for primexine formation andsporopollenin deposition during microspore development.

The effect of cyfluthrin on testis inhibin B in rats and the intervention of Lycium barbarum polysaccharide

Guo Xin,Xie Yong-Xin,Guo Chen,Wei Jing-Lin,Yang Hui-Fang 대한독성 유전단백체 학회 2021 Molecular & cellular toxicology Vol.17 No.2

Background In recent years, studies have shown that cyfluthrin is harmful to the reproductive system. Lycium barbarum polysaccharide may be a protective agent. Objective To investigate the effect of cyfluthrin (Cy) on testosterone B (inhibin B, INHB) in male rats and the intervention of Lycium barbarum polysaccharide (LBP). Results Compared with the control group, the mRNA and protein expression levels of INH α and INH βB in the testis tissue decreased, and the difference was statistically significant (P < 0.05). The LBP intervention group can significantly increase the expression level, and the difference is statistically significant (P < 0.05). Conclusion The decrease of INHα and INHβB expression caused by Cy exposure indicates that Cy has a toxic effect on the testis of rats, and the addition of LBP has a certain protective effect on the testis of rats. Background In recent years, studies have shown that cyfluthrin is harmful to the reproductive system. Lycium barbarum polysaccharide may be a protective agent. Objective To investigate the effect of cyfluthrin (Cy) on testosterone B (inhibin B, INHB) in male rats and the intervention of Lycium barbarum polysaccharide (LBP). Results Compared with the control group, the mRNA and protein expression levels of INH α and INH βB in the testis tissue decreased, and the difference was statistically significant (P < 0.05). The LBP intervention group can significantly increase the expression level, and the difference is statistically significant (P < 0.05). Conclusion The decrease of INHα and INHβB expression caused by Cy exposure indicates that Cy has a toxic effect on the testis of rats, and the addition of LBP has a certain protective effect on the testis of rats.