Biodegradable cross-linked poly(L-lactide-co-e-caprolactone) networks for ureteral stent formed by gamma irradiation under vacuum

Xiliang Liu,Song Liu,Youkun Fan,Jin Qi,Xin Wang,Wei Bai,Dongliang Chen,Chengdong Xiong,Lifang Zhang 한국공업화학회 2021 Journal of Industrial and Engineering Chemistry Vol.104 No.-

The poly(L-lactide-co-e-caprolactone) (PLCL) ureteral stent creeps and loses shape stability, increasingthe risk of stent tube dislocation. The rubbery biodegradable cross-linked PLCL networks were preparedthrough gamma irradiation under vacuum in the presence of trimethylolpropane triacrylate (TMPTA),pentaerythritol tetraacrylate (PET4A), and pentaerythritol triacrylate (PETA). At a standard sterilizationdose of 25 kGy, the gel content and network density of PLCL networks increased with increasingcrosslinking agent content (1, 3, 5, 7 wt%), and crosslinking efficiency decreased in the order ofPETA > PET4A > TMPTA. The average molecular weight (Mc ) between two crosslinks ranged from 2000to 105 g/mol. To perform the beneficial semi-interpenetrated polymer network and characterized bythe principle, the networks were processed in several doses (25, 50, 75, 100, and 125 kGy). In place ofthe Charlesby-Pinner equation, the irradiation cross-linking followed the Chen-Liu-Tang equation. ThePLCL network with 7 wt% PETA had a gel fraction of 83%, tensile strength of 34.7 MPa, and tensile setvalue as low as 5%. Furthermore, degradation in vitro was slowed down. Thus, PLCL networks with appropriateelasticity and flexibility, inherent biodegradability, and excellent biocompatibility can provide apromising alternative method for soft tissue repair engineering, such as ureteral stents.

Systematic equity risk change around convertible debt offerings

Lifang Chen,Lixin Xu 인하대학교 정석물류통상연구원 2009 인하대학교 정석물류통상연구원 학술대회 Vol.2009 No.10

This study investigates Systematic Equity Risk Change of a firm when it issues convertible bonds by studying the change in beta before and after the issuance of convertible bonds. Descriptive statistics provide the evidence that the systematic equity risk declines slightly after a firm has issued convertible debt, while the systematic equity risk was low both before and after issuance. However, both the T test and Wilcoxon signed-rank test of the paired-samples show that there appears to be no significant change in the systematic equity risk after a firm has issued convertible bonds. Although the conclusion is different from previous studies, it is consistent with and gives further support to the conjecture that firms try to stabilize the level of systematic risk of their common stock. Moreover, our results have implications for existing theories and suggest that it is important to consider possible risk changes when examining the issuance effects of offering convertible bonds.

Does Kiitricha (Protista, Ciliophora, Spirotrichea) belong to Euplotida or represent a primordial spirotrichous taxon? With suggestion to establish a new subclass Protohypotrichia.

Li, Lifang,Shao, Chen,Song, Weibo,Lynn, Denis H,Chen, Zigui,Shin, Mann Kyoon Society for General Microbiology 2009 International journal of systematic and evolutiona Vol.59 No.2

<P>The genus Kiitricha was long assumed to be the most primordial taxon in the Stichotrichia [hypotrichs sensu lato (s. l.)] based on its morphological features and was considered to be an intermediate between heterotrichs and the traditional hypotrichous assemblage. In order to evaluate the phylogenetic position of Kiitricha within the Hypotrichia, we sequenced the small-subunit rRNA gene and the alpha-tubulin gene for a Qingdao population of Kiitricha marina. Phylogenetic trees were constructed and compared to morphological and morphogenetic data. The results show that (i) Kiitricha is positioned near Phacodinium, both of which always form a sister clade to the assemblage including Stichotrichia, Hypotrichia, Oligotrichia and Choreotrichia, (ii) Kiitricha, which may represent an intermediate between heterotrichs (s. l.) and the Stichotrichia-Hypotrichia complex, is probably an ancestor-like form of the latter group and (iii) in contrast to morphological characters, both molecular and ontogenetic data support the separation of Kiitricha from the hypotrichs (s. l.). Thus, Kiitricha might be placed in the class Spirotrichea at about subclass level, next to Phaconidiidia, Hypotrichia and Stichotrichia, which supports the establishment of a new subclass Protohypotrichia n. subclass within the class Spirotrichea, with characterizations including slightly differentiated somatic ciliature (i.e. cirri on the ventral side generally uniform and non-grouped, no clearly defined marginal cirral rows, ciliature on the dorsal side mixed with cirri and dikinetids, no clearly differentiated dorsal kineties) and a unique but intermediate morphogenetic pattern of cortical structures between Hypotrichia and Stichotrichia.</P>

Knockdown of microtubule actin crosslinking factor 1 inhibits cell proliferation in MC3T3-E1 osteoblastic cells

( Lifang Hu ),( Peihong Su ),( Runzhi Li ),( Kun Yan ),( Zhihao Chen ),( Peng Shang ),( Airong Qian ) 생화학분자생물학회(구 한국생화학분자생물학회) 2015 BMB Reports Vol.48 No.10

Microtubule actin crosslinking factor 1 (MACF1), a widely expressed cytoskeletal linker, plays important roles in various cells by regulating cytoskeleton dynamics. However, its role in osteoblastic cells is not well understood. Based on our previous findings that the association of MACF1 with F-actin and microtubules in osteoblast-like cells was altered under magnetic force conditions, here, by adopting a stable MACF1- knockdown MC3T3-E1 osteoblastic cell line, we found that MACF1 knockdown induced large cells with a binuclear/multinuclear structure. Further, immunofluorescence staining showed disorganization of F-actin and microtubules in MACF1-knockdown cells. Cell counting revealed significant decrease of cell proliferation and cell cycle analysis showed an S phase cell cycle arrest in MACF1-knockdown cells. Moreover and interestingly, MACF1 knockdown showed a potential effect on cellular MTT reduction activity and mitochondrial content, suggesting an impact on cellular metabolic activity. These results together indicate an important role of MACF1 in regulating osteoblastic cell morphology and function. [BMB Reports 2015; 48(10): 583-588]

The Application of ANP Models in the Web-Based Course Development Quality Evaluation of Landscape Design Course

Xiaoyu Chen,Lifang Qiao 보안공학연구지원센터 2015 International Journal of Multimedia and Ubiquitous Vol.10 No.9

Web-based course is the important method in the landscape design teaching. In this paper, the ANP (Analytic Network Process) model has been adopted to evaluate the quality of the development of on-line courses, so as to provide the basis for preferred on-line courses. Conclude 10 evaluation indicators from 3 aspects of teaching, availability, and technology, and establish ANP model consisting of control layer, network layer, and alternatives. Four web-based courses of landscape design were chosen as the evaluation objects and the SD (Super Decisions) software was used to conduct the calculation. The result shows that: ANP is a practical science decision analysis method, comprehensively considering the mutually influential and feedback relationships of indicators, and is suitable for the evaluation and decision of the complex problems. The development quality evaluation of ANP which is applied in landscape design web-based courses is feasible, and the result of research can provide decision basis to web-based course development.

Applicable Prospects of Eye Tracking Technology in the Research of Landscape Visual Perception

Xiaoyu Chen,Lifang Qiao 보안공학연구지원센터 2015 International Journal of Multimedia and Ubiquitous Vol.10 No.10

This paper mainly adopts the literature research method, which analyzes the application progress and development overview of the eye tracking technology, as well as the technical features of the eye tracking devices. Combined with the research needs in landscape visual perception, eye tracking technology have application values in the following aspects: landscape attractiveness analysis, safety design of landscape environment, usability design of landscape facilities, landscape perception in motion, quality improvement of landscape information interface, cognitive analysis of physiological vulnerable groups and quality improvement of landscape education. Eye- tracking technology should be used reasonably in the study so as to exploit its advantages to the full and correct its deficiencies. The development of hardware technology and software technology of eye-tracking offers a new perspective and study platform for the study on landscape visual perception, which contributes to improving the scientificity of the study on landscape visual perception.

In silico identification of potential drug targets in swine pathogen Haemophilus parasuis

Zhuofei Xu,Lifang Ma,Huanchun Chen,Rui Zhou 한국유전학회 2012 Genes & Genomics Vol.34 No.2

Gram-negative bacterium Haemophilus parasuis has recently become one of the most important etiological agents causing serious systemic disease (Glässer’s disease) in pigs. Antibiotic therapy has played a crucial role in the treatment of this disease. Antibiotic resistance observed from the clinical isolates of this pathogen urges us to discover novel drug targets for antimicrobial agents. In this study, we used a combined strategy including exploration of the gene essentiality and comparison of metabolic pathways to infer drug targets of H. parasuis. We identified 931 gene products essential for bacterial growth according to the DEG database. One hundred and ninety-nine enzyme-coding genes were found in the genome of H. parasuis but were absent in that of the swine host. Lastly,we determined 117 enzymes exhibiting essentiality and specificity to H. parasuis as a candidate set of drug targets. Comparison of metabolic pathways between the pathogen and host showed that 25 targeting enzymes belonged to nine unique pathways of the pathogen. The profile of promising targets identified in our study will provide a useful basis for developing more effective antibiotics against the severe swine disease caused by H. parasuis.

Orthorhombic carbon oC24: A novel topological nodal line semimetal

Li, Zhen-Zhen,Chen, Jia,Nie, Simin,Xu, Lifang,Mizuseki, Hiroshi,Weng, Hongming,Wang, Jian-Tao Elsevier 2018 Carbon Vol.133 No.-

<P><B>Abstract</B></P> <P>We identify by <I>ab initio</I> calculations a stable three-dimensional carbon allotrope that constructed by inserting benzene rings into the carbon-carbon bonds in a previously reported oC8 carbon. This new carbon phase has a 24-atom orthorhombic unit cell in C m m m ( D 2 H 19 ) symmetry and thus termed oC24. Phonon mode analysis confirms its dynamical stable. Total-energy calculations show that it is energetically stable comparable with (5,5) carbon nanotube. Detailed electronic band calculations reveal that oC24 is a topological node-line semimetal with two mirror-inversion symmetric nodal lines that go through the whole Brillouin zone in bulk and a projected surface flat band around the Fermi level. The present results establish a new type of carbon phases and offer insights into their outstanding structural and electronic properties.</P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Hierarchical Vertex Regression-Based Segmentation of Head and Neck CT Images for Radiotherapy Planning

Wang, Zhensong,Wei, Lifang,Wang, Li,Gao, Yaozong,Chen, Wufan,Shen, Dinggang IEEE 2018 IEEE TRANSACTIONS ON IMAGE PROCESSING - Vol.27 No.2

<P>Segmenting organs at risk from head and neck CT images is a prerequisite for the treatment of head and neck cancer using intensity modulated radiotherapy. However, accurate and automatic segmentation of organs at risk is a challenging task due to the low contrast of soft tissue and image artifact in CT images. Shape priors have been proved effective in addressing this challenging task. However, conventional methods incorporating shape priors often suffer from sensitivity to shape initialization and also shape variations across individuals. In this paper, we propose a novel approach to incorporate shape priors into a hierarchical learning-based model. The contributions of our proposed approach are as follows: 1) a novel mechanism for critical vertices identification is proposed to identify vertices with distinctive appearances and strong consistency across different subjects; 2) a new strategy of hierarchical vertex regression is also used to gradually locate more vertices with the guidance of previously located vertices; and 3) an innovative framework of joint shape and appearance learning is further developed to capture salient shape and appearance features simultaneously. Using these innovative strategies, our proposed approach can essentially overcome drawbacks of the conventional shape-based segmentation methods. Experimental results show that our approach can achieve much better results than state-of-the-art methods.</P>

Optimization of Biodrying Pretreatment of Municipal Solid Waste and Microbial Fuel Cell Treatment of Leachate

Yuan Haoran,Deng Lifang,Chen Yong 한국생물공학회 2014 Biotechnology and Bioprocess Engineering Vol.19 No.4

The biodrying pretreatment of municipal solidwaste (MSW) and the treatment of leachate were investigated. The biological oxygen demand (BOD) and NH4+-Nconcentration of leachate from MSW biodrying pretreatmentwere measured, and the optimal conditions for MSWbiodrying pretreatment and microbial fuel cell (MFC)performance were established. The results show that theoptimal temperature and time for biodrying pretreatment ofMSW were 40°C and 6 day, resulting in 30% weight lossof MSW, 20,800 mg/L leachate BOD, and 1,410 mg/Lleachate NH4+-N. Effects of leachate properties on MFCperformance were then studied. The optimal conditions forelectricity generation of the MFC were neutral pH,5,093 mg/L leachate BOD, and 341 mg/L leachate NH4+-N. The stable voltage of MFC generated using diluted leachatewas 0.32 V, and the removal efficiencies of BOD andNH4+-N by the MFC were 86.0 and 88.8% after 7 day oftreatment, respectively. These findings provide guidelinesfor the pretreatment of MSW and the treatment of leachate,and for further research and actual engineering application.