Lipase Immobilization on Magnetic Microspheres via Spacer Arms: Effect of Steric Hindrance on the Activity

Dong-Hao Zhang,Ya-Qiong Li,Li-Juan Peng,Na Chen 한국생물공학회 2014 Biotechnology and Bioprocess Engineering Vol.19 No.5

Poly(styrene-acrylic acid) magnetic microsphereswith an average diameter of 2 μm were successfullyprepared and used as carriers to immobilize lipase. Lipaseimmobilized on microspheres with no spacer arm exhibitedlow activities, which were attributed to steric hindranceon the lipase conformation. To avoid steric effects,ethylenediamine and poly(ethylene glycol) (PEG) 400/800/4000 were utilized as spacer arms to bind the lipase tothe microspheres. The immobilized lipase activities wereimproved using PEG 800/4000 as a spacer arm. Furthermore,the influence of enzyme loading on lipase activity wasinvestigated, and the results indicated that enzymeoverloading could exert steric effect on lipase activity. Thedegree of PEG modification was demonstrated to affectlipase activity because excess PEG on the surface ofmicrospheres could interact with lipase due to its mobility,consequently reducing lipase activity.

Influence of errors and floating on static load-sharing characteristics of twin rotors concentric face-gear power-split transmission system

Hao Dong,Hao-Qin Zhang,Gang Liang,Bing-Xing Ren,Xiao-Long Zhao 대한기계학회 2023 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.37 No.4

Twin rotors concentric face-gear power-split transmission system (TRCFGPSTS) is a new and more advanced main reducer configuration of the high-speed helicopter. Its loadsharing performance between different branches has a great impact on the service life performance. Its load distribution is complex, and the research on the influence law of error on loadsharing performance is not clear. Therefore, to study the influence of system error and pinions floating on the mechanical properties of the system, the static load-sharing mathematical model of the system was established. The load-sharing model comprehensively considers the factors of manufacturing error (ME) and installation error (IE), meshing stiffness, torsional stiffness, support stiffness and member floating. The coordination conditions of torsional angle elastic deformation of the system with central displacement offset and the mechanical balance conditions under the action of elastic support and floating support are derived, which reflects the change law of load distribution from the perspective of the system as a whole. The load-sharing model is solved by the least square method. The load-sharing coefficient (LSC) of the system is obtained. The influence of ME, IE and floating pinions on load-sharing performance is analyzed. The results show that the LSC shows irregular periodic fluctuation under the combined action of error, and the LSC is 1.212. Under the single influence of ME, the LSC also shows irregular periodic fluctuation, and the LSC is 1.610. Under the single influence of IE, the LSC presents a constant influence law, and the LSC is 1.326. The error of each gear in the III-stage has the most obvious influence on the load-sharing characteristics. The LSC of I-stage and II-stage floating pinion under the single influence are 1.113 and 1.120, respectively. The floating gear can significantly improve the load-sharing performance, and meet the load-sharing at the ±5 % service requirement.

Kinetics of Enzymatic Synthesis of L-ascorbyl Acetate by Lipozyme TLIM and Novozym 435

Dong-Hao Zhang,Ya-Qiong Li,Chao Li,Yv-Qin Lv,Yang-L 한국생물공학회 2012 Biotechnology and Bioprocess Engineering Vol.17 No.1

L-ascorbyl acetate was synthesized through lipase-catalyzed esterification using Lipozyme TLIM and Novozym 435. Four solvents, including methanol, ethanol,acetonitrile, and acetone were investigated for the reaction,and acetone and acetonitrile were found to be suitable reaction media. The influences of several parameters such as water activity (aw), substrate molar ratio, enzyme loading,and reaction temperature on esterification of Lascorbic acid were systematically and quantitatively analyzed. Through optimizing the reaction, lipase-catalyzed esterification of L-ascorbic acid gave a maximum conversion of 99%. The results from using Lipozyme TLIM and Novozym 435 as biocatalysts both showed that aw was an important factor for the conversion of L-ascorbic acid. The effect of pH value on lipase-catalyzed L-ascorbic acid esterification in acetone was also investigated. Furthermore,results from a kinetic characterization of Lipozyme TLIM were compared with those for Novozym 435, and suggested that the maximum reaction rate for Lipozyme TLIM was greater than that for Novozym 435, while the enzyme affinity for substrate was greater for Novozym 436.

SIRT3-mediated mitochondrial unfolded protein response weakens breast cancer sensitivity to cisplatin

Chen Hao,Zhang Dong-Ming,Zhang Zhi-Ping,Li Ming-Zhang,Wu Hai-Feng 한국유전학회 2021 Genes & Genomics Vol.43 No.12

Background Mitochondrial unfolded protein response plays an important role in the occurrence and development of breast cancer. However, the role of mitochondrial unfolded protein response (UPRmt) in the sensitivity of breast cancer to cisplatin chemotherapy has not yet been cleared. Objectives The purpose of this study is to explore the role of mitochondrial unfolded protein response in breast cancer sensitivity to cisplatin. Methods In this study, qRT-PCR, Western blotting, Immunofuorescence, CCK-8, Colony formation, Transwell assay and TUNEL staining assay were used to confrm the role of UPRmt in breast cancer cells treated with cisplatin. Results Cisplatin increased the levels of UPRmt including CLPP, HSP60, LONP1 in MCF7 and MDA-MB-231 cells. UPRmt inducer Nicotinamide ribose (NR) could promote the proliferation and invasion of breast cancer cells treated with cisplatin. Importantly, SIRT3 was discovered to increase UPRmt in breast cancer cells and silencing of SIRT3 could inhibit the efect of NR in breast cancer. Conclusions UPRmt regulated by SIRT3 could protect breast cancer cell from cisplatin. Controlling SIRT3-induced UPR may be a potential therapeutic target to increase the sensitivity of breast cancer chemotherapy.

Effect of Harvesting Times on the Fruit Quality in Squashes

Cheng-hao Zhang,Zhi-Hao Xu,Juan-Li Lei,Wei-Song Shou,Wen-Qi Dong,Jae-Wook Lee,Il-Seop Kim,Hyung-Kweon Yun 한국원예학회 2008 한국원예학회 기타간행물 Vol.- No.-

Effectiveness and Safety of Dabrafenib in the Treatment of 20 Chinese Children with BRAFV600E-Mutated Langerhans Cell Histiocytosis

Ying Yang,Dong Wang,Lei Cui,Hong-Hao Ma,Li Zhang,Hong-Yun Lian,Qing Zhang,Xiao-Xi Zhao,Li-Ping Zhang,Yun-Ze Zhao,Na Li,Tian-You Wang,Zhi-Gang Li,Rui Zhang 대한암학회 2021 Cancer Research and Treatment Vol.53 No.1

Purpose We sought to investigate the effectiveness and safety of dabrafenib in children with BRAFV600E-mutated Langerhans cell histiocytosis (LCH). Materials and Methods A retrospective analysis was performed on 20 children with BRAFV600E-mutated LCH who were treated with dabrafenib. Results The median age at which the patients started taking dabrafenib was 2.3 years old (range, 0.6 to 6.5 years). The ratio of boys to girls was 2.3:1. The median follow-up time was 30.8 months (range, 18.9 to 43.6 months). There were 14 patients (70%) in the risk organ (RO)+ group and six patients (30%) in the RO– group. All patients were initially treated with traditional chemotherapy and then shifted to targeted therapy due to poor control of LCH or intolerance to chemotherapy. The overall objective response rate and the overall disease control rate were 65% and 75%, respectively. During treatment, circulating levels of cell-free BRAFV600E (cfBRAFV600E) became negative in 60% of the patients within a median period of 3.0 months (range, 1.0 to 9.0 months). Grade 2 or 3 adverse effects occurred in five patients. Conclusion Some children with BRAFV600E-mutated LCH may benefit from monotherapy with dabrafenib, especially high-risk patients with concomitant hemophagocytic lymphohistiocytosis and intolerance to chemotherapy. The safety of dabrafenib is notable. A prospective study with a larger sample size is required to determine the optimal dosage and treatment duration.

Codelivery of hydrophilic and hydrophobic drugs in a microneedle patch for the treatment of skin pigmentation

Li Qin Zhang,Xiao Peng Zhang,Yu Ying Hao,Bao Li Zhang,Xin Dong Guo 한국공업화학회 2020 Journal of Industrial and Engineering Chemistry Vol.88 No.-

When overexposed to ultraviolet B (UVB) irradiation, skin can cause a series of abnormal reactions, suchas excessive pigmentation and solar elastosis. In order to better treat the skin after overexposed to UVB,we designed a dissolving microneedles (MNs) loading hydrophilic ascorbic acid and hydrophobic vitaminA palmitate to achieve codelivery. Here, we confirmed that MNs had enough mechanical strength toinsert the skin and two drugs were delivered subcutaneously in sequence in vitro. In white guinea pigs,surface observation and histological observation results confirmed that two drugs by MNs transdermaldelivery were better than topical administration in the treatment of UVB-damaged skin. The MNs providea method of loading different drugs into the needles and advance the development of transdermal drugdelivery.

Reduction of the contact resistance in copper phthalocyanine thin film transistor with UV/ozone treated Au electrodes

Jun Li,Liang Zhang,Xiao-Wen Zhang,Hao Zhang,Xue-Yin Jiang,Dong-bin Yu,Wen-Qing Zhu,Zhi-Lin Zhang 한국물리학회 2010 Current Applied Physics Vol.10 No.5

Bottom-contact (BC) copper phthalocyanine (CuPc) thin film transistor with UV/ozone treated Au as a source/drain electrode was fabricated and the contact resistance was estimated from the transmission line method (TLM). Comparing the properties of OTFT with untreated Au electrode, the performance of the BC CuPc-TFT with the UV/ozone treated Au electrodes was significantly improved: saturation mobility increased from 4.69 × 10−3 to 2.37 × 10−2 ㎠/V s, threshold voltage reduced from −29.1 to −6.4 V, and threshold swing varied from 5.08 to 2.25 V/decade. The contact resistance of the device with UV/ozone treated Au electrodes was nearly 20 times smaller than that of the device with untreated Au electrodes at the gate voltage of −20 V. This result indicated that using the UV/ozone treated Au electrode is an effective method to reduce the contact resistance. The present BC configuration with UV/ozone treated Au electrodes could be a significant step towards the commercialization of OTFT technology.

Serum Zinc Status and Helicobacter Pylori Infection in Gastric Disease Patients

Zhang, Wen-Hua,Wu, Xiao-Jing,Niu, Jing-Xiu,Yan, Hao,Wang, Xin-Zhuo,Yin, Xiao-Dong,Pang, Yan Asian Pacific Journal of Cancer Prevention 2012 Asian Pacific journal of cancer prevention Vol.13 No.10

The role of Helicobacter pylori status and serum zinc value in gastric disease patients and healthy controls were investigated. Cases used in this work were 45 gastric cancer patients, 44 with peptic ulcers, 52 suffering gastritis and 64 healthy controls, all diagnosed histologically with the controls undergoing medical checkups. Helicobacter pylori status and serum levels of Zn were determined by 13C-urea breath test and flame atomic absorption spectrophotometer, respectively. Our study showed that Helicobacter pylori infection has no change in gastritis, peptic ulcer and gastric cancer group, on the contrast, serum levels of Zn were significantly reduced in gastritis, peptic ulcer and gastric cancer group, compared with healthy controls, and the higher the Zn levels are, the more increased risk of gastric cancer. Helicobacter pylori infection is a cause of gastritis, peptic ulcers and even gastric cancer, while serum zinc level is an indicator of protection of gastric membranes against damage.

Bioconversion of conjugated linoleic acid by Lactobacillus plantarum CGMCC8198 supplemented with Acer truncatum bunge seeds oil

Dong-Ju Chen,Li-Hua Yan,Qian Li,Cai-jiao Zhang,Chuan-Ling Si,Zhong-Yuan Li,Ya-Jian Song,Hao Zhou,Tong-Cun Zhang,Xuegang Luo 한국식품과학회 2017 Food Science and Biotechnology Vol.26 No.6

Conjugated linoleic acid (CLA) isomers, c9, t11- CLA and t10, c12-CLA, have been proved to exhibit excellent biomedical properties for potential use in anticancer applications and in reducing obesity. Acer truncatum Bunge (ATB), which is rich in unsaturated fatty acids, including oleic acid, linoleic acid, and nervonic acid, is a new resource for edible oil. In the present study, we developed a new method for producing two CLA isomers from ATB-seed oil by fermentation using Lactobacillus plantarum CGMCC8198 (LP8198), a novel probiotics strain. Polymerase chain reaction results showed that there was a conserved linoleate isomerase (LIase) gene in LP8198, and its transcription could be induced by ATBseed oil. Analyses by gas chromatography–mass spectrometry showed that the concentration of c9, t11-CLA and t10, c12-CLA in ATB-seed oil could be increased by about 9- and 2.25-fold, respectively, after being fermented by LP8198.