ON THE MEAN VALUES OF L(1, χ)

Wu, Zhaoxia,Zhang, Wenpeng Korean Mathematical Society 2012 대한수학회보 Vol.49 No.6

Let $p$ > 2 be a prime, and let $k{\geq}1$ be an integer. Let ${\chi}$ be a Dirichlet character modulo $p$, and let $L(s,{\chi})$ be the Dirichlet L-function corresponding to ${\chi}$. In this paper we consider the mean values of $$\sum_{{\chi}\;mod\;p\\{\chi}(-1)=-1}{\chi}(2^k)|L(1,\chi)|^2$$.

ON THE MEAN VALUES OF L(1, χ)

Zhaoxia Wu,Wenpeng Zhang 대한수학회 2012 대한수학회보 Vol.49 No.6

Let $p$ > 2 be a prime, and let $k{\geq}1$ be an integer. Let χ be a Dirichlet character modulo $p$, and let $L(s,{\chi})$ be the Dirichlet L-function corresponding to χ. In this paper we consider the mean values of $$\sum_{{\chi}\;mod\;p\\{\chi}(-1)=-1}{\chi}(2^k)|L(1,\chi)|^2$$.

Multiscale features and information extraction of online strain for long-span bridges

Wu, Baijian,Li, Zhaoxia,Chan, Tommy H.T.,Wang, Ying Techno-Press 2014 Smart Structures and Systems, An International Jou Vol.14 No.4

The strain data acquired from structural health monitoring (SHM) systems play an important role in the state monitoring and damage identification of bridges. Due to the environmental complexity of civil structures, a better understanding of the actual strain data will help filling the gap between theoretical/laboratorial results and practical application. In the study, the multi-scale features of strain response are first revealed after abundant investigations on the actual data from two typical long-span bridges. Results show that, strain types at the three typical temporal scales of $10^5$, $10^2$ and $10^0$ sec are caused by temperature change, trains and heavy trucks, and have their respective cut-off frequency in the order of $10^{-2}$, $10^{-1}$ and $10^0$ Hz. Multi-resolution analysis and wavelet shrinkage are applied for separating and extracting these strain types. During the above process, two methods for determining thresholds are introduced. The excellent ability of wavelet transform on simultaneously time-frequency analysis leads to an effective information extraction. After extraction, the strain data will be compressed at an attractive ratio. This research may contribute to a further understanding of actual strain data of long-span bridges; also, the proposed extracting methodology is applicable on actual SHM systems.

Application of Dynamic Regulation to Increase L-Phenylalanine Production in Escherichia coli

Wu, Jie,Liu, Yongfei,Zhao, Sheng,Sun, Jibin,Jin, Zhaoxia,Zhang, Dawei The Korean Society for Microbiology and Biotechnol 2019 Journal of microbiology and biotechnology Vol.29 No.6

Current strategies of strain improvement processes are mainly focused on enhancing the synthetic pathways of the products. However, excessive metabolic flux often creates metabolic imbalances, which lead to growth retardation and ultimately limit the yield of the product. To solve this problem, we applied a dynamic regulation strategy to produce $\text\tiny{L}$-phenylalanine ($\text\tiny{L}$-Phe) in Escherichia coli. First, we constructed a series of Phe-induced promoters that exhibited different strengths through modification of the promoter region of tyrP. Then, two engineered promoters were separately introduced into a Phe-producing strain xllp1 to dynamically control the expression level of one pathway enzyme AroK. Batch fermentation results of the strain xllp3 showed that the titer of Phe reached 61.3 g/l at 48 h, representing a titer of 1.36-fold of the strain xllp1 (45.0 g/l). Moreover, the $\text\tiny{L}$-Phe yields on glucose of xllp3 (0.22 g/g) were also greatly improved, with an increase of 1.22-fold in comparison with the xllp1 (0.18 g/g). In summary, we successfully improved the titer of Phe by using dynamic regulation of one key enzyme and this strategy can be applied for improving the performance of strains producing other aromatic amino acids and derived compounds.

Multiscale features and information extraction of online strain for long-span bridges

Baijian Wu,Zhaoxia Li,Tommy H.T. Chan,Ying Wang 국제구조공학회 2014 Smart Structures and Systems, An International Jou Vol.14 No.4

The strain data acquired from structural health monitoring (SHM) systems play an important role in the state monitoring and damage identification of bridges. Due to the environmental complexity of civil structures, a better understanding of the actual strain data will help filling the gap between theoretical/laboratorial results and practical application. In the study, the multi-scale features of strain response are first revealed after abundant investigations on the actual data from two typical long-span bridges. Results show that, strain types at the three typical temporal scales of 105, 102 and 100 sec are caused by temperature change, trains and heavy trucks, and have their respective cut-off frequency in the order of 10-2, 10-1 and 100 Hz. Multi-resolution analysis and wavelet shrinkage are applied for separating and extracting these strain types. During the above process, two methods for determining thresholds are introduced. The excellent ability of wavelet transform on simultaneously time-frequency analysis leads to an effective information extraction. After extraction, the strain data will be compressed at an attractive ratio. This research may contribute to a further understanding of actual strain data of long-span bridges; also, the proposed extracting methodology is applicable on actual SHM systems.

Application of Dynamic Regulation to Increase L-Phenylalanine Production in Escherichia coli

( Jie Wu ),( Yongfei Liu ),( Sheng Zhao ),( Jibin Sun ),( Zhaoxia Jin ),( Dawei Zhang ) 한국미생물생명공학회(구 한국산업미생물학회) 2019 Journal of microbiology and biotechnology Vol.29 No.6

Current strategies of strain improvement processes are mainly focused on enhancing the synthetic pathways of the products. However, excessive metabolic flux often creates metabolic imbalances, which lead to growth retardation and ultimately limit the yield of the product. To solve this problem, we applied a dynamic regulation strategy to produce L-phenylalanine (LPhe) in Escherichia coli. First, we constructed a series of Phe-induced promoters that exhibited different strengths through modification of the promoter region of tyrP. Then, two engineered promoters were separately introduced into a Phe-producing strain xllp1 to dynamically control the expression level of one pathway enzyme AroK. Batch fermentation results of the strain xllp3 showed that the titer of Phe reached 61.3 g/l at 48 h, representing a titer of 1.36- fold of the strain xllp1 (45.0 g/l). Moreover, the L-Phe yields on glucose of xllp3 (0.22 g/g) were also greatly improved, with an increase of 1.22-fold in comparison with the xllp1 (0.18 g/ g). In summary, we successfully improved the titer of Phe by using dynamic regulation of one key enzyme and this strategy can be applied for improving the performance of strains producing other aromatic amino acids and derived compounds.

Risk Factors Predicting Upper Urinary Tract Damage in Patients With Myelodysplasia: Data Analysis of 637 Cases From A Single Center

Han Deng,Zhaoxia Wang,Limin Liao,Juan Wu,Yue Wang 대한배뇨장애요실금학회 2022 International Neurourology Journal Vol.26 No.S1

Purpose: To determine the risk factors predicting upper urinary tract (UUT) damage using a grading system for upper urinary tract dilation (UUTD) and a descriptive system for all urinary tract dysfunction (AUTD) in patients with myelodysplasia. Methods: Six hundred thirty-seven patients with myelodysplasia were evaluated at our center from January 2008 to November 2019. Clinical data, ultrasonography, magnetic resonance urography, and video-urodynamics (VUDS) parameters were collected. Univariate and multivariate analyses were used to determine the risk factors predicting UUT damage. Results: Three hundred eighty-three males and 254 females were included. The average course of lower urinary tract symptoms (LUTS) was 14.08±7.07 years (range, 3–31 years). The urodynamic diagnoses of all patients were as follows: detrusor overactivity, 26.8%; detrusor underactivity, 6.44%; and acontractile detrusor, 66.72%. UUT damage was determined in 66.56% of the patients. Of the patients, 28.73 % had vesicoureteral reflux (VUR) during filling (bilateral, n=50; unilateral, n=133) on fluoroscopy during VUDS testing. Two hundred thirty-four patients had UUTD (bilateral, n=203; unilateral, n=31). The occurrence of hydronephrosis based on ultrasonography was closely related to ipsilateral VUR (P<0.05). Absent of bladder sensation, long-term course of LUTS, decreased maximum cystometric capacity (MCC) and bladder compliance (BC), and increased postvoid residual urine (PVR) were shown to be independent risk factors in logistic regression analysis. Conclusions: This retrospective study using UUTD and AUTD systems indicated that patients with myelodysplasia have a high incidence of UUT damage. Absence of bladder sensation, long-term course of LUTS, decreased MCC and BC, and increased PVR were independent risk factors predicting UUT damage.

LKB1 on POMC neurons affect the formation of diet-induced obesity by regulating the expression of HDAC1

Zhang Yan,Wu Zhaoxia,Xi Pengjiao,Wang Haomin,Zhu Wenjuan,Tian Derun 한국유전학회 2022 Genes & Genomics Vol.44 No.4

Background: Obesity is considered a major public health issue worldwide. Liver Kinase B1 (LKB1) is a serine/threonine kinase, peripheral LKB1 is involved in obesity by regulating adipogenesis, but the role of central LKB1 in the development of obesity remains unclear. Objective: This study aims to explore the main role of LKB1 in POMC neurons on obesity, and reveal the underlying mechanism of central LKB1 affecting obesity through quantitative proteomics. Methods: We constructed POMC neuron specific LKB1 knockout mice (PomcLkb1 KO) and exposed them to high fat diet intervention for three months. The effect of LKB1 knockout on obesity was evaluated by monitoring body weight, food intake and measuring fat content. The hypothalamus tissues were collected for proteomic analysis and validated by RT-PCR. Results: The degree of obesity was aggravated in PomcLkb1 KO mice fed with high fat diet. Proteomic results showed that only Histone deacetylase 1 (HDAC1) was down-regulated in the hypothalamus of PomcLkb1 KO mice. Our research also found that LKB1 knockout on POMC neurons led to reduction of Peroxisome proliferator-activated receptor γ (PPARγ). Meanwhile, the software predicted that the transcription factor PPARγ binds to the HDAC1 promoter. Therefore, we speculated that central LKB1 may regulate diet-induced obesity development by influencing HDAC1/PPARγ expression. Conclusion: We firstly found that central LKB1 may affect the development of obesity by regulating the expression of HDAC1, which provides a new idea for the central regulatory mechanism of obesity.

A triage strategy in advanced ovarian cancer management based on multiple predictive models for R0 resection: a prospective cohort study

Zheng Feng,Hao Wen,Zhaoxia Jiang,Shuai Liu,Xingzhu Ju,Xiaojun Chen,Lingfang Xia,Junyan Xu,Rui Bi,Xiaohua Wu 대한부인종양학회 2018 Journal of Gynecologic Oncology Vol.29 No.5

Objective: To present the surgical outcomes of advanced epithelial ovarian cancer (AEOC) since the implementation of a personalized approach and to validate multiple predictive models for R0 resection. Methods: Personalized strategies included: 1) Non-invasive model: preoperative clinico-radiological assessment according to Suidan criteria with a predictive score for all individuals. Patients with a score 0–2 were recommended for primary debulking surgery (PDS, group A), or otherwise were counseled on the choices of PDS, neoadjuvant chemotherapy (NAC, group B) or staging laparoscopy (S-LPS). 2) Minimally invasive model: S-LPS with a predictive index value (PIV) according to Fagotti. Individuals with a PIV <8 underwent PDS (group C) or otherwise received NAC (group D). Intraoperative assessment (with Eisenkop, peritoneal cancer index [PCI], and Aletti scores) and surgical results were prospectively collected. Results: Between September 2015 and August 2017, 161 pathologically confirmed epithelial ovarian cancer patients were included. A total of 52 (32.3%) patients had a predictive score of 0–2, and 109 (67.7%) patients had a score ≥3. Among these individuals, 41 (25.5%) patients received S-LPS. Finally, 110 (68.3%) patients underwent PDS (A+C), and 51 (31.7%) patients received NAC (B+D). The R0 resection rates in PDS and NAC patients were 56.4% and 60.8%, respectively. The area under the curve (AUC) of Suidan criteria was 0.548 for group (A+C). The AUC of Fagotti score was 0.702 for group C. The AUC of Eisenkop, PCI, and Aletti scores were 0.808, 0.797, and 0.524, respectively. Conclusion: The Suidan criteria were not effective in these AEOC patients. S-LPS was helpful in decision-making for PDS and should be endorsed in the future.

Investigation on the application of industrial grade MgO in the alkaline peroxide bleaching of poplar CTMP

Song Han,Wei Liu,Shaoshuai Wu,Zhaoxia Long,Qingxi Hou 한국공업화학회 2015 Journal of Industrial and Engineering Chemistry Vol.21 No.1

Effects of four different kinds of industrial grade MgO as one alkali source in the alkaline peroxidebleaching of poplar chemi-thermomechanical pulp (CTMP) were investigated. The particle size andactivity of the MgO played the most important role in the improvement of optical and strengthproperties of the bleached CTMP. At a 25% substitution percentage of MgO for NaOH, a 77.4%ISObrightness and the optimal tensile index of the bleached CTMP could be obtained. When industrial gradeMgO was applied, appropriate increase in Na2SiO3 dosage and pulp consistency could improve thebrightness and strength properties of the bleached CTMP.