Finite-element analysis and design of aluminum alloy RHSs and SHSs with through-openings in bending

Ran Feng,Tao Yang,Zhenming Chen,Krishanu Roy,Boshan Chen,James B. P. Lim 국제구조공학회 2023 Steel and Composite Structures, An International J Vol.46 No.3

This paper presents a finite-element analysis (FEA) of aluminum alloy rectangular hollow sections (RHSs) and square hollow sections (SHSs) with circular through-openings under three-point and four-point bending. First, a finite-element model (FEM) was developed and validated against the corresponding test results available in the literature. Next, using the validated FE models, a parametric study comprising 180 FE models was conducted. The cross-section width-to-thickness ratio (b/t) ranged from 2 to 5, the hole size ratio (d/h) ranged from 0.2 to 0.8 and the quantity of holes (n) ranged from 2 to 6, respectively. Third, results obtained from laboratory test and FEA were compared with current design strengths calculated in accordance with the North American Specifications (NAS), the modified direct strength method (DSM) and the modified Continuous strength method (CSM). The comparison shows that the modified CSM are conservative by 15% on average for aluminum alloy RHSs and SHSs with circular through-openings subject to bending. Finally, a new design equation is proposed based on the modified CSM after being validated with results obtained from laboratory test and FEA. The proposed design equation can provide accurate predictions of flexural capacities for aluminum alloy RHSs and SHSs with circular throughopenings.

Cell-Selective Metabolic Glycan Labeling Based on Ligand-Targeted Liposomes

Ran Xie,Senlian Hong,Lianshun Feng,Jie Rong,Xing Chen 한국당과학회 2012 한국당과학회 학술대회 Vol.2012 No.1

Cell-surface glycans play key roles in mediating various molecular recognition events; aberrant glycosylation is implicated in disease progression. Therefore, probing the dynamic changes of glycan biosynthesis and structures is of great importance for augmenting our understanding of glycobiology and improving disease diagnosis and therapeutics. The metabolic glycan labeling was an appealing approach to incorporate specially designed carbohydrate analogs into the glycans, which enables the detection and imaging of the glycans in cells and living animals. However, one major bottleneck of this method is cell- type selectivity. Herein, we present the cell-specific metabolic glycan labeling using ligand-targeted liposomes to deliver unnatural sugars to target cells in a cell-surface receptor dependent manner. In this strategy, sugar analogs are encapsulated in ligand-targeted liposomes. The ligands bind to specific cell-surface receptors that are only expressed or up-regulated in target cells, which mediate the intracellular delivery of azidosugars via endocytosis. The delivered azidosugars are metabolically incorporated into cell-surface glycans and detected or imaged using a bioorthogonal reaction. The application of this strategy includes the facile introduction of myriad alternative ligands, as well as the cell-specific or tissue-specific imaging and detection of glycosylation in vivo.

Construction of Mammalian Cell Expression Vector for pAcGFP-bFLIP(L) Fusion Protein and Its Expression in Follicular Granulosa Cells

Yang, Run Jun,Li, Wu Feng,Li, Jun Ya,Zhang, Lu Pei,Gao, Xue,Chen, Jin Bao,Xu, Shang Zhong Asian Australasian Association of Animal Productio 2010 Animal Bioscience Vol.23 No.3

FLICE inhibitory protein (FLIP) is one of the important anti-apoptotic proteins in the Fas/FasL apoptotic path which has death effect domains, mimicking the pro-domain of procaspase-8. To reveal the intracellular signal transduction molecules involved in the process of follicular development in the bovine ovary, we cloned the c-FLIP(L) gene in bovine ovary tissue with the reverse transcription polymerase chain reaction (RT-PCR), deleted the termination codon in its cDNA, and directionally cloned the amplified c-FLIP(L) gene into eukaryotic expression vector pAcGFP-Nl, including AcGFP, and successfully constructed the fusion protein recombinant plasmid. After identifying by restrictive enzyme BglII/EcoRI and sequencing, pAcGFP-bFLIP(L) was then transfected into follicular granulosa cells, mediated by Lipofectamine 2000, the expression of AcGFP observed and the transcription and expression of c-FLIP(L) detected by RT-PCR and Western blot. The results showed that the cattle c-FLIP(L) was successfully cloned; the pAcGFPbFLIP(L) fusion protein recombinant plasmid was successfuly constructed by introducing a BglII/EcoRI cloning site at the two ends of the c-FLIP(L) open reading frame and inserting a Kozak sequence before the start codon. AcGFP expression was detected as early as 24 h after transfection. The percentage of AcGFP positive cells reached about 65% after 24 h. A 1,483 bp transcription was amplified by RT-PCR, and a 83 kD target protein was detected by Western blot. Construction of the pAcGFP-bFLIP(L) recombinant plasmid should be helpful for further understanding the mechanism of regulation of c-FLIP(L) on bovine oocyte formation and development.

Evaluation on Dry Sliding Wear Behavior of (TiB+TiC)/Ti- 6Al-4V Matrix Composite

Zi-Run Yang,Hai-Xiang Huan,Cui-Feng Jiang,Wen-Min Li,Xue-Ran Liu,류성기 한국정밀공학회 2017 International Journal of Precision Engineering and Vol.18 No.8

The dry sliding wear tests were performed for 10 vol.% (TiB+TiC)/Ti-6Al-4V matrix composites at various test conditions. The morphology and phases of worn surfaces and cross-sectional surfaces were investigated by using scanning electron microscopy (SEM) and X-ray diffraction (XRD). The wear loss of composites with the increase of load, but the wear behavior got more complex when the sliding speed and ambient temperature got higher. Low wear loss was achieved at lower sliding speed with higher temperature or higher sliding speed with lower temperature. A tribo-layer was always formed on worn surface during testing. It possessed different features and thus presented different effects during sliding wear. Meanwhile, the TiB and TiC particulates strengthened the Ti-6Al- 4V matrix, which increased the thermal stability of composites and postponed the occurrence of severe plastic deformation. In the mild wear region, those particulates could directly resist wear by reducing adhesive wear. In the steady stage, fractured TiB and TiC particulates participated in forming the tribo-layer together with wear debris, which effectively hindered the plastic deformation and thermal softening of the matrix. Experiment results suggest that the existence of different characteristic tribo-layers would result in the variation of wear behavior.

The Effect of Functional MA Film Packaging on Storage of Mature-Red Tomato

Jun Feng Guan,Hyung Woo Park,Yoon Ho Kim,Sang Hee Kim,Hye Ran Park,Seon Ah Lee,Ji Yoon Yoon 한국포장학회 2005 한국포장학회지 Vol.11 No.2

토마토(Pinky 종)를 기능성 MA필름(두께 0.03, 0.06mm)으로 포장하여 0, 5, 15℃에 저장하면서 품질 변화를 조사하였다. 저장 29일에 MA포장재 내의 CO2, O2농도는 각각 4.21~8.17%, 9.78~14.45%였고, 전반적으로 MA 포장구에서 연화와 색택의 변화가 억제되었다. 저장 29일에 MA포장(0.03두께)을 한 후 5℃에 저장한 토마토의 경도(0.49 kgf)가 가장 높았고, MA 포장(0.06두께)을 한 후 0℃에 저장한 토마토가 최소 라이코펜 함량(6.08mg/100g)을 보였다. 토마토의 품질 유지를 위한 최적 조건은 MA 장을 하여 0℃에 저장하는 것이 바람직한 것으로 나타났으며 필름 두께간에는 유의적인 차이가 나타나지 않았다. 또한 MA 포장재 내의 최적 가스 조성은 CO2는 4.2%~5.6%, O2는 14.3%~14.5%로 나타났다. The mature-red tomato fruits (cv. Pinky world) were packaged with functional modified atmosphere (MA) film (0.03, 0.06 mm) and stored at 0, 5, 15℃. The results showed that the concentrations of CO2 and O2 inside MA package were about 4.21~8.17% and 9.78~14.45% under steady state during storage 29 days at 0, 5℃, respectively. The MA packaging(MAP) suppressed the fruits softening and the color change. The minimum lycopene content and maximum firmness were separately observed in fruits packaged with MA film (0.03 mm) at 5℃ storage and film(0.06 mm) at 0℃, which the lycopene content 6.08 mg/100 g, and firmness was 0.49 Kgf at 29 th day storage. The optimal conditions to keep high quality of tomato fruits were obtained by MAP during storage at 0℃ for 29 days, independently of the film thickness, in which the adequate gas composition was CO2 at 4.2%~5.6%, O2 at 14.3%~14.5%, respectively.

칼슘처리와 MA포장이 딸기의 품질에 미치는 영향

( Jun Feng Guan ),박형우 ( Hyung Woo Park ),김윤호 ( Yoon Ho Kim ),김상희 ( Sang Hee Kim ),박혜란 ( Hye Ran Park ) 한국식품저장유통학회 ( 구 한국농산물저장유통학회 ) 2006 한국식품저장유통학회지 Vol.13 No.1

Gut microbiota metabolic characteristics in coronary artery disease patients with hyperhomocysteine

Tian Ran,Liu Hong-Hong,Feng Si-Qin,Wang Yi-Fei,Wang Yi-Yang,Chen Yu-Xiong,Wang Hui,Zhang Shu-Yang 한국미생물학회 2022 The journal of microbiology Vol.60 No.4

Hyperhomocysteine (HHcy) is known as a risk factor for coronary artery disease (CAD). Despite the knowledge that gut microbiota related metabolism pathway shares metabolites with that of Hcy, little has been shown concerning the association between HHcy and gut microbiota. To explore their relationship in the context of CAD, 105 patients and 14 healthy controls were recruited from one single medical center located in Beijing, China. Their serum and fecal samples were collected, with multi-omics analyses performed via LC/MS/ MS and 16S rRNA gene V3-V4 region sequencing, respectively. Participants from the prospective cohort were divided into CAD, CAD & HHcy and healthy controls (HC) groups based on the diagnosis and serum Hcy concentration. The results revealed significant different metabolic signatures between CAD and CAD & HHcy groups. CAD patients with HHcy suffered a heavier atherosclerotic burden compared to CAD patients, and the difference was closely associated to betaine-homocysteine S-methyltransferase (BHMT)-related metabolites and trimethylamine N-oxide (TMAO)-related metabolites. Dimethylglycine (DMG) exhibited a strong positive correlation with serum total Hcy (tHcy), and TMAO and trimethylysine (TML) were associated with heavier atherosclerotic burden. Multiple other metabolites were also identified to be related to distinct cardiovascular risk factors. Additionally, Clostridium cluster IV and Butyricimonas were enriched in CAD patients with elevated tHcy. Our study suggested that CAD patients with elevated tHcy were correlated with higher atherosclerotic burden, and the impaired Hcy metabolism and cardiovascular risk were closely associated with BHMT-related metabolites, TMAO-related metabolites and impaired gut microbiota homeostasis.

Phosphodiesterase 4D contributes to angiotensin II-induced abdominal aortic aneurysm through smooth muscle cell apoptosis

Gao Ran,Guo Wenjun,Fan Tianfei,Pang Junling,Hou Yangfeng,Feng Xiaohang,Li Bolun,Ge Weipeng,Fan Tianhui,Zhang Tiantian,Lu Jiakai,Jing He,Jin Mu,Yan Chen,Wang Jing 생화학분자생물학회 2022 Experimental and molecular medicine Vol.54 No.-

Abdominal aortic aneurysm (AAA) is a permanent expansion of the abdominal aorta that has a high mortality but limited treatment options. Phosphodiesterase (PDE) 4 family members are cAMP-specific hydrolyzing enzymes and have four isoforms (PDE4A-PDE4D). Several pan-PDE4 inhibitors are used clinically. However, the regulation and function of PDE4 in AAA remain largely unknown. Herein, we showed that PDE4D expression is upregulated in human and angiotensin II-induced mouse AAA tissues using RT-PCR, western blotting, and immunohistochemical staining. Furthermore, smooth muscle cell (SMC)-specific Pde4d knockout mice showed significantly reduced vascular destabilization and AAA development in an experimental AAA model. The PDE4 inhibitor rolipram also suppressed vascular pathogenesis and AAA formation in mice. In addition, PDE4D deficiency inhibited caspase 3 cleavage and SMC apoptosis in vivo and in vitro, as shown by bulk RNA-seq, western blotting, flow cytometry and TUNEL staining. Mechanistic studies revealed that PDE4D promotes apoptosis by suppressing the activation of cAMP-activated protein kinase A (PKA) instead of the exchange protein directly activated by cAMP (Epac). Additionally, the phosphorylation of BCL2-antagonist of cell death (Bad) was reversed by PDE4D siRNA in vitro, which indicates that PDE4D regulates SMC apoptosis via the cAMP-PKA-pBad axis. Overall, these findings indicate that PDE4D upregulation in SMCs plays a causative role in AAA development and suggest that pharmacological inhibition of PDE4 may represent a potential therapeutic strategy.

Stathmin is a Marker of Progression and Poor Prognosis in Esophageal Carcinoma

Wang, Feng,Xuan, Xiao-Yan,Yang, Xuan,Cao, Lei,Pang, Li-Na,Zhou, Ran,Fan, Qin-Xia,Wang, Liu-Xing Asian Pacific Journal of Cancer Prevention 2014 Asian Pacific journal of cancer prevention Vol.15 No.8

Stathmin, also called oncoprotein 18, is a founding member of the family of microtubule-destabilizing proteins that play a critical role in the regulation of mitosis. At the same time stathmin has been recognized as one of responsible factors in cancer cells. The aim of this study was to assess stathmin status, its correlations with clinicopathological parameters and its role as a progosnostic marker in EC patients. The protein and mRNA levels of stathmin were examined byimmunohistochemistry (IHC) and in situ hybridization in 100EC tissues and adjacent noncancerous tissues. mRNA and protein expression of stathmin in three EC cell lines(EC9706, ECa109, EC1 commonly used in research) were also analyzed using immunocytochemistry, western blot and in situ hybridization. The prognostic value of Stathmin expression within the tumor tissues were assessed by Cox regression and Kaplan-Meier analysis. We showed that stathmin expression was significantly higher in EC tissues than in adjacent noncancerous tissues. High stathmin immunostaining score in the EC was positively correlated with tumor differentiation, Tumor invasion, Lymph node metastases, and TNM stage. In addition, we demonstrated that three EC cell lines examined, were constitutively expressing a high level of stathmin. Of those, EC-1 showed the strongest mRNA and protein expression for the stathmin analyzed. Kaplan-Meier analysis showed that significantly longer 5-year survival rate was seen in EC patients with high Stathmin expression, compared to those with low expression of Stathmin expression. Furthermore, multivariate Cox proportional hazard analyses revealed that Stathmin was an independent factors affecting the overall survival probability. In conclusion, our data provide a basis for the concept that stathmin might be associated with EC development and progression. High levels of Stathmin expression in the tumor tissues may be a good prognostic marker for patients with EC.

Influence of Nitrate Feeding on Carbon Dioxide Fixation by Microalgae

JIN, HAI-FENG,LIM, BYUNG-RAN,LEE, KISAY Taylor Francis 2006 Journal of Environmental Science and Health. Part Vol.41 No.12

<P>In this study, the effects of nitrate feeding on microalgal growth and associated CO<SUB>2</SUB> fixation were evaluated, as a strategy to enhance carbon fixation by increasing the duration of the exponential phase of cell growth in the batch operation of a photobioreactor. Two species of green algae, <I>Chlorella</I> and <I>Scenedesmus</I>, and two species of cyanobacteria, <I>Microcystis ichthyoblabe</I> and <I>Microcystis aeruginosa</I>, were used after adaptation to a 15% (v/v) CO<SUB>2</SUB> environment. In the absence of nitrate feeding, nitrate concentrations declined rapidly and soon became a limiting factor. Nitrate feeding, administered in fed-batch mode to maintain 15–20 ppm of NO<SUB>3</SUB>-N, allowed for an extension of the exponential growth phase by more than 3 days, as well as a higher cell density, which subsequently resulted in an increase in photoautotrophic carbon fixation. The increases in the carbon fixation rate were in the ranges of 56.1–56.6% for the green algae, and between 68.2–68.8% for the cyanobacteria. The results indicated that intermittent nitrate feeding was a viable strategy for the augmentation of fixation productivity, and may thus be effectively applied as a substitute for conventional medium change, which has traditionally been employed in order to prolong the active growth duration.</P>