Pneumococcal wall teichoic acid is required for the pathogenesis of Streptococcus pneumoniae in murine models

Hongmei Xu,Libin Wang,Jian Huang,YanQing Zhang,Feng Ma,Jianmin Wang,WenChun Xu,XueMei Zhang,YiBing Yin,KaiFeng Wu 한국미생물학회 2015 The journal of microbiology Vol.53 No.2

Pneumococcal asymptomatic colonization of the respiratory tracts is a major risk for invasive pneumococcal disease. We have previously shown that pneumococcal wall teichoic acid (WTA) was involved in pneumococcal infection of sepsis and adherence to epithelial and endothelial cells. In this study, we investigated the contribution of pneumococcal WTA to bacterial colonization and dissemination in murine models. The result showed that nasopharynx colonizing D39 bacterial cells have a distinct phenotype showing an increased exposure of teichoic acids relative to medium-grown bacteria. The WTA-deficient mutants were impaired in their colonization to the nasopharynx and lungs, and led to a mild inflammation in the lungs at 36 h post-inoculation. Pretreatment of the murine nares with WTA reduced the ability of wild type D39 bacteria to colonize the nasopharynx. In addition, the WTA-deficient strain was impaired in its ability to invade the blood and brain following intranasal administration. WTA-deficient D39 strain was reduced in C3 deposition but was more susceptible to the killing by the neutrophils as compared with its parent strain. Our results also demonstrated that the WTA enhanced pneumococcal colonization and dissemination independently of the host strains. These results indicate that WTA plays an important role in pneumococcal pathogenesis, both in colonization and dissemination processes.

A note on linear combinations of an idempotent matrix and a tripotent matrix

Hongmei Yao,Yanling Sun,CHUANG XU,CHANGJIANG BU 한국전산응용수학회 2009 Journal of applied mathematics & informatics Vol.27 No.5

Let A1 and A2 be nonzero complex idempotent and tripotent matrix, respectively. Denote a linear combination of the two matrices by A = c1A1 + c2A2, where c1, c2 are nonzero complex scalars. In this paper, under an assumption of A1A2 = A2A1, we characterize all situations in which the linear combination is tripotent. A statistical interpretation of this tripotent problem is also pointed out. Moreover, In [2], Baksalary characterized all situations in which the above linear combination is idempotent by using the property of decomposition of a tripotent matrix, i.e. if A2 is tripotent, then A2 = B1 −B2, where B2 i = Bi, i = 1, 2 and B1B2 = B2B1 = 0. While in this paper, by utilizing a method different from the one used by Baksalary in [2], we prove the theorem 1 in [2] again. Let A1 and A2 be nonzero complex idempotent and tripotent matrix, respectively. Denote a linear combination of the two matrices by A = c1A1 + c2A2, where c1, c2 are nonzero complex scalars. In this paper, under an assumption of A1A2 = A2A1, we characterize all situations in which the linear combination is tripotent. A statistical interpretation of this tripotent problem is also pointed out. Moreover, In [2], Baksalary characterized all situations in which the above linear combination is idempotent by using the property of decomposition of a tripotent matrix, i.e. if A2 is tripotent, then A2 = B1 −B2, where B2 i = Bi, i = 1, 2 and B1B2 = B2B1 = 0. While in this paper, by utilizing a method different from the one used by Baksalary in [2], we prove the theorem 1 in [2] again.

Digital Post-processing Techniques for Time-interleaved ADCs

Hongmei Chen,Lanyu Wang,Jian Wang,Jiashen Li,Honghui Deng,Xu Meng,Yongsheng Yin 대한전자공학회 2022 IEIE Transactions on Smart Processing & Computing Vol.11 No.6

This paper presents an all-digital post-processing circuit for a high-speed and highprecision time-interleaved ADC (TIADC). By pre-inputting a test signal in the TIADC, channel mismatch errors are estimated and stored, and the stored values are extracted to compensate for errors when the input signal is at a special frequency. The frequency can be detected by a threshold judgement module. This solves the problem of the traditional modulation calibration algorithm, which cannot calibrate the signal at a special frequency. A high-speed low-complexity digital down converter (DDC) circuit with an optional decimation ratio of 1, 2, 4, or 8 times was designed to have different frequency outputs of the TIADC. We applied it to a four-channel 14-bit 360-MHz TIADC system with an input signal fin of 110 MHz. The FPGA verification results show that after calibration and decimation, the spurious-free dynamic range (SFDR) and signal-to-noise distortion ratio (SNDR) improve by about 40 dB and 30 dB, respectively.

A NOTE ON LINEAR COMBINATIONS OF AN IDEMPOTENT MATRIX AND A TRIPOTENT MATRIX

Yao, Hongmei,Sun, Yanling,Xu, Chuang,Bu, Changjiang The Korean Society for Computational and Applied M 2009 Journal of applied mathematics & informatics Vol.27 No.5

Let $A_1$ and $A_2$ be nonzero complex idempotent and tripotent matrix, respectively. Denote a linear combination of the two matrices by A = $c_1A_1$ + $c_2A_2$, where $c_1,\;c_2$ are nonzero complex scalars. In this paper, under an assumption of $A_1A_2$ = $A_2A_1$, we characterize all situations in which the linear combination is tripotent. A statistical interpretation of this tripotent problem is also pointed out. Moreover, In [2], Baksalary characterized all situations in which the above linear combination is idem-potent by using the property of decomposition of a tripotent matrix, i.e. if $A_2$ is tripotent, then $A_2$ = $B_1-B_2$, where $B^2_i=B_i$, i = 1, 2 and $B_1B_2=B_2B_1=0$. While in this paper, by utilizing a method different from the one used by Baksalary in [2], we prove the theorem 1 in [2] again.

Equilibrium, kinetic and mechanism studies on the biosorption of Cu2+ and Ni2+ by sulfur-modified bamboo powder

Tian Ai,Xiaojun Jiang,Hongmei Yu,Hong-Bo Xu,Dawei Pan,Qingyu Liu,Dongyu Chen,Jinyang Li 한국화학공학회 2015 Korean Journal of Chemical Engineering Vol.32 No.2

Two biosorbents were prepared using bamboo powder modified with mercaptoacetic acid and carbondisulfide, which exhibits strong adsorption properties for Cu2+ and Ni2+. The obtained materials were characterized byFTIR. Maximum adsorption for both metals was found to occur around pH 5.0-6.5. The kinetic data followed thepseudo-second-order model. The maximum adsorption capacities of Cu2+ and Ni2+ on mercaptoacetic acid modifiedbamboo powder determined from Langmuir isotherm were 103.97mg g−1 and 61.35mg g−1, respectively. While oncarbon disulfide modified bamboo powder were 128.21mg g−1 and 56.82mg g−1, respectively. The adsorption mechanismanalysis revealed that the most possible adsorption mode of Cu2+ was coordination, and Ni2+ was ion exchange. The obtained adsorbents could effectively remove Cu2+ and Ni2+ from industrial electroplating wastewater and could beused repeatedly for more than five cycles.

Topology optimization of the photovoltaic panel connector in high-rise buildings

Xilin Lu,Jiaqi Xu,Hongmei Zhang,Peng Wei 국제구조공학회 2017 Structural Engineering and Mechanics, An Int'l Jou Vol.62 No.4

Photovoltaic (PV) panels are used in high-rise buildings to convert solar energy to electricity. Due to the considerable energy consumption of high-rise buildings, applying PV technology is of great significance to energy saving. In the application of PV panels, one of the most important construction issues is the connection of the PV panel with the main structures. One major difficulty of the connection design is that the PV panel connection consists of two separate components with coupling and indeterminate dimension. In this paper, the gap element is employed in these two separated but coupled components, i.e., hook and catch. Topology optimization is applied to optimize and design the cross-section of the PV panel connection. Pareto optimization is conducted to operate the optimization subject to multiple load scenarios. The initial design for the topology optimization is determined by the common design specified by the Technical Code for Glass Curtain Wall Engineering (JGJ 102-2003). Gravity and wind load scenarios are considered for the optimization and numerical analysis. Post analysis is conducted for the optimal design obtained by the topology optimization due to the manufactory requirements. Generally, compared with the conventional design, the optimized connector reduces material use with improved structural characteristics.

Production of Recombinant Human Papillomavirus Type 52 L1 Protein in Hansenula polymorpha Formed Virus-Like Particles

Liu, Cunbao,Yao, Yufeng,Yang, Xu,Bai, Hongmei,Huang, Weiwei,Xia, Ye,Ma, Yanbing The Korean Society for Microbiology and Biotechnol 2015 Journal of microbiology and biotechnology Vol.25 No.6

Human papillomavirus (HPV) type 52 is a high-risk HPV responsible for cervical cancer. HPV type 52 is common around the world and is the most common in some Asian regions. The available prophylactic HPV vaccines protect only from HPV types 16 and 18. Supplementing economical vaccines that target HPV type 52 may satisfactorily complement available prophylactic vaccines. A codon-adapted HPV 52 L1 gene was expressed in the methylotrophic yeast Hansenula polymorpha, which is used as an industrial platform for economical hepatitis B surface antigen particle production in China. We found that the recombinant proteins produced in this expression system could form virus-like particles (VLPs) with diameters of approximately 50 nm. This study suggests that the HPV 52 VLPs produced in this platform may satisfactorily complement available prophylactic vaccines in fighting against HPVs prevalent in Asia.

Granularity and Laxative Effect of Ultrafine Powder of Dendrobium officinale

DanDan Luo,Chao Qu,ZhenBiao Zhang,JianHui Xie,LieQiang Xu,HongMei Yang,CaiLan Li,GuoSheng Lin,HongFeng Wang,ZiRen Su 한국식품영양과학회 2017 Journal of medicinal food Vol.20 No.2

Constipation is a common disorder that is a significant source of morbidity among people around the world ranging from 2% to 28%. Dendrobium officinale Kimura et Migo is a traditional herbal medicine and health food used for tonicity of the stomach and promotion of body fluid production in China. This study aimed to prepare the ultrafine powder of Dendrobium officinale (UDO) and investigate its laxative effect and potential mechanism in mice with diphenoxylate-induced constipation. Results indicated that the mean diameter (d50) of UDO obtained by ball milling was 6.56 lm. UDO (62.5, 125, and 250 mg/kg, p.o.) could significantly enhance the gastrointestinal transit ratio and promote fecal output. Moreover, UDO treatment resulted in significant increases in the serum levels of acetylcholinesterase (AChE), gastrin (Gas), motilin (MTL), and substance P (SP), and obviously decreased serum contents of somatostatin (SS). Taken together, UDO, which can be easily obtained through milling to a satisfactory particle size, exhibited obvious laxative effect in diphenoxylate-induced constipated mice, and the mechanism might be associated with elevated levels of AChE, Gas, MTL, SP, and reduced production of SS. UDO has the potential for further development into an alternative effective diet therapy for constipation.

Interaction of the Lysophospholipase PNPLA7 with Lipid Droplets through the Catalytic Region

Chang, Pingan,Sun, Tengteng,Heier, Christoph,Gao, Hao,Xu, Hongmei,Huang, Feifei Korean Society for Molecular and Cellular Biology 2020 Molecules and cells Vol.43 No.3

Mammalian patatin-like phospholipase domain containing proteins (PNPLAs) play critical roles in triglyceride hydrolysis, phospholipids metabolism, and lipid droplet (LD) homeostasis. PNPLA7 is a lysophosphatidylcholine hydrolase anchored on the endoplasmic reticulum which associates with LDs through its catalytic region (PNPLA7-C) in response to increased cyclic nucleotide levels. However, the interaction of PNPLA7 with LDs through its catalytic region is unknown. Herein, we demonstrate that PNPLA7-C localizes to the mature LDs ex vivo and also colocalizes with pre-existing LDs. Localization of PNPLA7-C with LDs induces LDs clustering via non-enzymatic intermolecular associations, while PNPLA7 alone does not induce LD clustering. Residues 742-1016 contains four putative transmembrane domains which act as a LD targeting motif and are required for the localization of PNPLA7-C to LDs. Furthermore, the N-terminal flanking region of the LD targeting motif, residues 681-741, contributes to the LD targeting, whereas the C-terminal flanking region (1169-1326) has an anti-LD targeting effect. Interestingly, the LD targeting motif does not exhibit lysophosphatidylcholine hydrolase activity even though it associates with LDs phospholipid membranes. These findings characterize the specific functional domains of PNPLA7 mediating subcellular positioning and interactions with LDs, as wells as providing critical insights into the structure of this evolutionarily conserved phospholipid-metabolizing enzyme family.