BIFURCATION ANALYSIS OF A SINGLE SPECIES REACTION-DIFFUSION MODEL WITH NONLOCAL DELAY

Zhou, Jun Korean Mathematical Society 2020 대한수학회지 Vol.57 No.1

A reaction-diffusion model with spatiotemporal delay modeling the dynamical behavior of a single species is investigated. The parameter regions for the local stability, global stability and instability of the unique positive constant steady state solution are derived. The conditions of the occurrence of Turing (diffusion-driven) instability are obtained. The existence of time-periodic solutions, the existence and nonexistence of nonconstant positive steady state solutions are proved by bifurcation method and energy method. Numerical simulations are presented to verify and illustrate the theoretical results.

Palaeophytochemical Constituents from the Miocene-fossil Wood of Picea likiangensis in Xun-dian of Yunnan, China

Jun Zhou,You-Xing Zhao,Jian-Rong Luo,Cheng-Sen Li,Tie-Mei Yi 대한화학회 2008 Bulletin of the Korean Chemical Society Vol.29 No.8

The influence of bone graft procedures on primary stability and bone change of implants placed in fresh extraction sockets

Jun, Sang Ho,Park, Chang-Joo,Hwang, Suk-Hyun,Lee, Youn Ki,Zhou, Cong,Jang, Hyon-Seok,Ryu, Jae-Jun Korean Association of Maxillofacial Plastic and Re 2018 Maxillofacial Plastic Reconstructive Surgery Vol.40 No.-

Background: This study was to evaluate the effect of bone graft procedure on the primary stability of implants installed in fresh sockets and assess the vertical alteration of peri-implant bone radiographically. Methods: Twenty-three implants were inserted in 18 patients immediately after tooth extraction. The horizontal gap between the implant and bony walls of the extraction socket was grafted with xenografts. The implant stability before and after graft procedure was measured by Osstell Mentor as implant stability quotient before bone graft (ISQ bbg) and implant stability quotient after bone graft (ISQ abg). Peri-apical radiographs were taken to measure peri-implant bone change immediately after implant surgery and 12 months after implant placement. Data were analyzed by independent t test; the relationships between stability parameters (insertion torque value (ITV), ISQ abg, and ISQ bbg) and peri-implant bone changes were analyzed according to Pearson correlation coefficients. Results: The increase of ISQ in low primary stability group (LPSG) was 6.87 ± 3.62, which was significantly higher than the increase in high primary stability group (HPSG). A significant correlation between ITV and ISQ bbg (R = 0.606, P = 0.002) was found; however, age and peri-implant bone change were not found significantly related to implant stability parameters. It was presented that there were no significant peri-implant bone changes at 1 year after bone graft surgery. Conclusions: Bone graft procedure is beneficial for increasing the primary stability of immediately placed implants, especially when the ISQ of implants is below 65 and that bone grafts have some effects on peri-implant bone maintenance.

Orthogonal 방법을 통한 Poly(AM-DMDAAC)/MMT 고흡수성나노복합체 제조 연구

Jun Dong Yuan,Ming Zhou,Shuang Qiao Yang,Yong Guo Zhou,Nan Qin,Song Tao He,Dong Lai,Zhong Qiang Xie 한국고분자학회 2014 폴리머 Vol.38 No.1

A novel poly(AM-DMDAAC)/MMT superabsorbent nanocomposites are prepared by radical polymerizationusing ammonium persulfate (APS) and anhydrous sodium sulfite as a free radical initiator and N,N-methylene bisacrylamide(MBA) as a crosslinker. In this paper, an optimization study on the synthesis of superabsorbent nanocompositesis carried out. Orthogonal array experiment indicates that the optimized conditions is acrylamide (AM) content 23 wt%,diallyl dimethyl ammonium chloride (DMDAAAC) content 6 wt%, montmorillonite (MMT) content 4 wt%, initiatorcontent 0.2 wt% and crosslinker content 0.02 wt%. Under the optimization syntheses conditions concluded, the maximumwater absorbency in distilled water is 659.53 g·g-1 and in 2 wt% sodium chloride solution is 116.25 g·g-1. Compared withthe range values of different factors (Rj), the order of significance factors in distilled water is C (MMT) > B (DMDAAC)> A (AM) > D (crosslinker) > E (initiator). MMT is intercalated during polymerization reaction and a nanocompositestructure is formed as shown by TEM analysis and XRD analysis.

Limited Diagnostic Value of microRNAs for Detecting Colorectal Cancer: A Meta-analysis

Zhou, Xuan-Jun,Dong, Zhao-Gang,Yang, Yong-Mei,Du, Lu-Tao,Zhang, Xin,Wang, Chuan-Xin Asian Pacific Journal of Cancer Prevention 2013 Asian Pacific journal of cancer prevention Vol.14 No.8

Background: MicroRNAs have been demonstrated to play important roles in the development and progression of colorectal cancer. Several studies utilizing microRNAs as diagnostic biomarkers for colorectal cancer (CRC) have been reported. The aim of this meta-analysis was to comprehensively and quantitatively summarize the diagnostic value of microRNAs for detecting colorectal cancer. Methods: We searched PubMed, Embase and Cochrane Library for published studies that used microRNAs as biomarkers for the diagnosis of colorectal cancer. Summary estimates for sensitivity, specificity and other measures of accuracy of microRNAs in the diagnosis of colorectal cancer were calculated using the bivariate random effects model. A summary receiver operating characteristic (SROC) curve was also generated to summarize the overall effectiveness of the test. Result: Thirteen studies from twelve published articles met the inclusion criteria and were included. The overall sensitivity, specificity, positive likelihood ratio, negative likelihood ratio and diagnostic odd ratio of microRNAs for the diagnosis of colorectal cancer were 0.81 (95%CI: 0.79-0.84), 0.78 (95%CI: 0.75-0.82), 4.14 (95%CI: 2.90-5.92), 0.24 (95%CI: 0.19-0.30), and 19.2 (95%CI: 11.7-31.5), respectively. The area under the SROC curve was 0.89. Conclusions: The current evidence suggests that the microRNAs test might not be used alone as a screening tool for CRC. Combining microRNAs testing with other conventional tests such as FOBT may improve the diagnostic accuracy for detecting CRC.

Systematic Review and Meta-Analysis of Antibiotic-Impregnated Shunt Catheters on Anti-Infective Effect of Hydrocephalus Shunt

Zhou, Wen-xiu,Hou, Wen-bo,Zhou, Chao,Yin, Yu-xia,Lu, Shou-tao,Liu, Guang,Fang, Yi,Li, Jian-wen,Wang, Yan,Liu, Ai-hua,Zhang, Hai-jun The Korean Neurosurgical Society 2021 Journal of Korean neurosurgical society Vol.64 No.2

Objective : Shunt infection is a common complication while treating hydrocephalus. The antibiotic-impregnated shunt catheter (AISC) was designed to reduce shunt infection rate. A meta-analysis was conducted to study the effectiveness of AISCs in reduction of shunt infection in terms of age, follow-up time and high-risk patient population. Methods : This study reviewed literature from three databases including PubMed, EMBASE, and Cochrane Library (from 2000 to March 2019). Clinical studies from controlled trials for shunt operation were included in this analysis. A subgroup analysis was performed based on the patient's age, follow-up time and high-risk population. The fixed effect in RevMan 5.3 software (Cochrane Collaboration) was used for this meta-analysis. Results : This study included 19 controlled clinical trials including 10105 operations. The analysis demonstrated that AISC could reduce the infection rate in shunt surgery compared to standard shunt catheter (non-AISC) from 8.13% to 4.09% (odds ratio [OR], 0.48; 95% confidence interval [CI], 0.40-0.58; p=0.01; I2=46%). Subgroup analysis of different age groups showed that AISC had significant antimicrobial effects in all three groups (adult, infant, and adolescent). Follow-up time analysis showed that AISC was effective in preventing early shunt infections (within 6 months after implant). AISC is more effective in high-risk population (OR, 0.24;95% CI, 0.14-0.40; p=0.60; I2=0%) than in general patient population. Conclusion : The results of meta-analysis indicated that AISC is an effective method for reducing shunt infection. We recommend that AISC should be considered for use in infants and high-risk groups. For adult patients, the choice for AISC could be determined based on the treatment cost.

Extraction and separation of D/L-lactic acid in simulated fermentation broth

Jun Zhou,노경호,Wentao Bi 한국화학공학회 2011 Korean Journal of Chemical Engineering Vol.28 No.7

The recovery of lactic acid from fermentation broth plays an important part in production of lactic acid. In this case, the extraction of lactic acid from simulated fermentation broth was processed by tri-n-octylamine dissolved in oleyl alcohol. The extraction efficiency was investigated with several variables, and the optimal condition of extraction of lactic acid (10 mg mL^−1) from aqueous solution was tri-n-octylamine/oleyl alcohol (30/70, v/v) and solvent phase/fermentation (1/2, v/v) stirred for 60 min under room temperature. The optimal back extraction of lactic acid was obtained by hot water (~90℃ ) with solvent phase/water (1/4, v/v). The back extracted racemic lactic acid was direct enantiomeric analyzed and separated by chiral ligand chromatography due to strict requirement of absolute configuration in pharmaceutical field and food science. The effect of various parameters on enantioselectivity was discussed and the (L)-phenylalaninamide·HCl (6.0 mmol L^−1) and CuSO^4·5H^2O (3.0 mmol L^−1) dissolved in methanol/water (5/95,v/v) at pH=6.0 was the suitable mobile phase for chiral ligand exchange separation of (D, L)-lactic acids. By the investigations,a convenient systemic method was established for extraction and separation of (D, L)-lactic acid.

GLOBAL ASYMPTOTIC STABILITY OF POSITIVE STEADY STATES OF AN n-DIMENSIONAL RATIO-DEPENDENT PREDATOR-PREY SYSTEM WITH DIFFUSION

Zhou, Jun Korean Mathematical Society 2013 대한수학회보 Vol.50 No.6

The main concern of this paper is to study the dynamics of an n-dimensional ratio-dependent predator-prey system with diffusion. We study the dissipativeness, persistence of the system and it is shown that the unique positive constant steady state is globally asymptotically stable under some assumptions.

Molecular and Biochemical Characterization of a Novel Intracellular Low-Temperature-Active Xylanase

( Jun Pei Zhou,),( Yan Yan Dong ),( Xiang Hua Tang ),( Jun Jun Li ),( Bo Xu ),( Qian Wu ),( Ya Jie Gao ),( Lu Pan ),( Zun Xi Huang ) 한국미생물 · 생명공학회 2012 Journal of microbiology and biotechnology Vol.22 No.4

A 990 bp full-length gene (xynAHJ2) encoding a 329- residue polypeptide (XynAHJ2) with a calculated mass of 38.4 kDa was cloned from Bacillus sp. HJ2 harbored in a saline soil. XynAHJ2 showed no signal peptide, distinct amino acid stretches of glycoside hydrolase (GH) family 10 intracellular endoxylanases, and the highest amino acid sequence identity of 65.3% with the identified GH 10 intracellular mesophilic endoxylanase iM-KRICT PX1-Ps from Paenibacillus sp. HPL-001 (ACJ06666). The recombinant enzyme (rXynAHJ2) was expressed in Escherichia coli and displayed the typical characteristics of low-temperatureactive enzyme (exhibiting optimum activity at 35 o C, 62% at 20 o C, and 38% at 10 o C; thermolability at ≥45 o C). Compared with the reported GH 10 low-temperature-active endoxylanases, which are all extracellular, rXynAHJ2 showed low amino acid sequence identities (<45%), low homology (different phylogenetic cluster), and difference of structure (decreased amount of total accessible surface area and exposed nonpolar accessible surface area). Compared with the reported GH 10 intracellular endoxylanases, which are all mesophilic and thermophilic, rXynAHJ2 has decreased numbers of arginine residues and salt bridges, and showed resistance to Ni 2+ , Ca 2+ , or EDTA at 10 mM final concentration. The above mechanism of structural adaptation for low-temperature activity of intracellular endoxylanase rXynAHJ2 is different from that of GH 10 extracellular low-temperature-active endoxylanases. This is the first report of the molecular and biochemical characterizations of a novel intracellular low-temperatureactive xylanase.

Intra-operative Rectal Washout with Saline Solution Can Effectively Prevent Anastomotic Recurrence: a Meta-analysis

Zhou, Can,Ren, Yu,Wang, Ke,Liu, Jie,He, Jian-Jun,Liu, Pei-Jun Asian Pacific Journal of Cancer Prevention 2013 Asian Pacific journal of cancer prevention Vol.14 No.12

Background and Objective: Rectal washout with saline solution may theoretically prevent anastomotic recurrence in patients with resectable rectal cancer, although exact clinical effects have not yet been determined. In order to derive a more precise estimation of the relationship, the present meta-analysis was performed. Method: Relevant studies were identified by a search of Medline, Embase and Google Website with no restrictions to September 1, 2013, and included in the systematic review and meta-analysis. Results: 5 trials (642 participants) were included to assess the association between rectal washout with saline solution and anastomotic recurrence. The rate of anastomotic recurrence (AR) was 6.23% (40/642), with the pooled OR derived from the five studies being 0.32 (95 % CI=0.15-0.70, P=0.004). The pooled OR derived from the TME and radical resection subgroups were 0.72 (95%CI=0.16-3.12, P=0.66) and 0.51 (95%CI=0.13-1.96, P=0.32), respectively. Conclusion: Results from this analysis show that intra-operative rectal washout with mere saline solution largely reduces the risk of anastomotic recurrences in patients with resectable rectal cancer.