Epsilon-Fe₂O₃ is a novel intermediate for magnetite biosynthesis in magnetotactic bacteria

Tong Wen,Yunpeng Zhang,Yuanyuan Geng,Junquan Liu,Abdul Basit,Jiesheng Tian,Ying Li,Ji-Lun Li,Jing Ju,Wei Jiang 한국생체재료학회 2019 생체재료학회지 Vol.23 No.3

Background: Natural biological magnetite nanoparticles are widely distributed from microorganisms to humans. It is found to be very important in organisms, especially in navigation. Moreover, purified magnetite nanoparticles also have potential applications in bioengineering and biomedicine. Magnetotactic bacteria (MTB) is considered one of the most abundant species around the world which can form intracellular membrane enveloped magnetic nanoparticles, referred to as magnetosomes. To our knowledge, the biomineralization of magnetosome in MTB involves a serious of genes located on a large unstable genomic region named magnetosome island, which specially exists in MTB. The magnetite core of magnetosome formed via a Fe (III) ion intermediates, for instance, α-Fe2O3 and ferrihydrite. Though the biosynthesis of magnetosome represents a general biomineralization mechanism of biogenic magnetite, knowledge of magnetosome biosynthesis and biomineralization remains very limited. Method: Cells used in this study were cultured in a 7.5-L bioreactor, samples for intermediate capture were taken each certain time interval after the generation of magnetosome biosynthesis condition. High-resolution transmission electron microscopy were used to analyze the detailed structure of magnetosomes. The parameters of the crystal structures were obtained by Fast Fourier Transform analyses. Results: In this study, we identified a novel intermediate phase, ε-Fe2O3, during the magnetite maturation process in MTB via kinetic analysis. Unlike α-Fe2O3, which has been reported as a precursor during magnetosome biosynthesis in MTB before, ε-Fe2O3, due to its thermal instability, is a rare phase with scarce natural abundance. This finding confirmed that ε-Fe2O3 is an important novel intermediate during the biomineralization of magnetosome in MTB, and shed new light on the magnetosome biosynthesis pathway.

Chinese Taipei Perspective on Key Educational Policies, Issues, and Cooperation in APEC regarding Regional Economic Integration

Wen Tong Lin APEC국제교육협력원 2012 국제교육협력연구지 Vol.5 No.1

본 논문에서는 현재 대만이 추진하고 있는 핵심 교육정책에 대해 다루고 있으며, 그 정책은 (1) 12년 의무교육, (2) 기술·직업 교육 개혁 방안, (3) 통합 유치원, 유아원 정책, (4) 대학 설립 및 폐교 기준 (5) 대학들의 국제적 명성 획득 전략 등으로 대표 된다. 이러한 교육 정책 실행 후 기대되는 효과로는 (1) 사회적 혜택을 받지 못하는 학생들을 위한 보조금 지급, (2) 출생률 저하에 따른 재능 교육 책정, (3) 고등교육의 국제화, (4) 교육-직업 간의 부조화 격차 감소가 있다. 또한 대만 정부는 APEC회원들과의 민간 및 공공 부문의 협조를 통하여 교육정책 효과 를 극대화하고자 하는 목표를 가지고 있다. 그리고 ‘지역 경제 통합’과 ‘녹색 성장’이라는 주제로 APEC에 국가 간 교육적 협력을 강화하기 위하여 다양한 제안을 성명하고 있다. Chinese taipei has implemented Key educational policies in Chinese Taipei such as (1) 12-year Compulsory Education, (2) Technological and Vocational Education, (3) Reform Project, (4) Integrated Kindergarten and Nursery School Policy, (5) Criteria for Establishing and Closing of Universities, (6) Strategies for Universities to Achieve International Recognition of Excellence. And there are expected results. (1) Grants Awarded to Disadvantaged Students, (2) Talent Education Measures in Response to Our Declining Birth Rate, (3) Internationalization of Higher Education, (4) Reducing the Education-Job Mismatch Gap. To be place in better position about this issue Chinese Taipei tries to corporate with APEC economies. Besides, Chinese Taipei has Recommendations for educational cooperation in APEC in relation to Regional Economic Integration (RED and Green Growth. Information Education for Elementary and Junior High Schools, Mandarin Chinese Teaching, Strengthened Mechanisms Regarding Student Internships between APEC member ,economies and Chinese Taipei, Working together for Green Growth.

Exhaust Air Energy Recovery System for Electrical Power Generation in Future Green Cities

Wen Tong Chong,Sin Chew Poh,Ahmad Fazlizan,Sook Yee Yip,Mei Hyie Koay,Wooi Ping Hew 한국정밀공학회 2013 International Journal of Precision Engineering and Vol. No.

This paper investigates a technology-driven solution to supply a portion of energy demand in future green cities. An idea on harnessing unnatural wind resources for electricity is presented. Two vertical axis wind turbines with an enclosure are mounted above a cooling tower to recover part of the energy from the exhaust air. Guide-vanes are designed to create a venturi effect and guide the wind before it interacts with the turbine blades. Diffuser-plates help to draw more wind and accelerate the exhaust airflow. Safety concerns that may result from blade failure are minimized by the design of the enclosure. From the laboratory test and field test results, there is no significant difference in the current consumption of the fan motor with the installation of the wind turbines. The integration of the enclosure has shown an improvement on the turbine’s rotational speed which is 30.4% higher. The electricity generated from this system can be fed into the electricity grid. For 3000 units of cooling tower (2 m outlet diameter powered by a 7.5 kW fan motor and operated for 16 hours/day), 13% of the energy to power the fan motor is expected to be recovered from this system which equals 17.5 GWh/year.

Stock Pledge by Controlling Shareholder and Corporate Social Responsibility

Tong Lijing,Wen Wen,Xie Lu,Zhang Siting 한국증권학회 2023 Asia-Pacific Journal of Financial Studies Vol.52 No.5

We examine the influence of stock pledge by controlling shareholders on corporate social responsibility (CSR). Results show that firms exhibit poorer CSR performance when the controlling shareholders have more shares under pledge to financial institutions. Further analyses suggest that the negative relation between stock pledge and CSR only exists in financially constrained firms and non‐state‐owned firms, in which the pledging controlling shareholders have greater incentive to increase stock price and maintain their control rights. Our findings support a margin call hypothesis that firms tend to cut off CSR spending to improve short‐term financial performance and reduce the risk of losing control rights.

Urban Eco-GreenergyTM Hybrid Wind-Solar Photovoltaic Energy System and Its Applications

Wen Tong Chong,Wan Khairul Muzammil,Ahmad Fazlizan,Mohamad Reza Hassan,Hamid Taheri,Mohammed Gwani,Hiren Kothari,Sin Chew Poh 한국정밀공학회 2015 International Journal of Precision Engineering and Vol. No.

This paper introduces the Eco-GreenergyTM hybrid wind-solar photovoltaic energy generation system and its applications. The system is an integration of the novel omni-direction-guide-vane (ODGV) with a vertical axis wind turbine (VAWT). The ODGV is designed to surround the VAWT for wind power augmentation by creating a venturi effect to increase the on-coming wind speed before it interacts with the turbine blades. In wind tunnel tests, the ODGV improves the power output of the VAWT by 3.48 times compared with a bare VAWT at its peak torque. Furthermore, the rotor rotational speed of the wind turbine increased by 182% at 6 m/s of wind speed. A solar PV panel can be mounted on the top surface of the ODGV for solar energy generation. Estimation on wind-solar energy output shows that the system can generate a total of 572.8 kWh of energy per year. By comparison, the ODGV increases the annual wind energy output by 438%. The green energy generated from the hybrid system can be used to power LED lights or other appliances (e.g., CCTV camera).

A novel M2e-multiple antigenic peptide providing heterologous protection in mice

Feng Wen,Ji-Hong Ma,Hai Yu,Fu-Ru Yang,Meng Huang,Yan-Jun Zhou,Ze-Jun Li,Xiu-Hui Wang,Guo-Xin Li,Yi-Feng Jiang,Wu Tong,Guangzhi Tong 대한수의학회 2016 Journal of Veterinary Science Vol.17 No.1

Swine influenza viruses (SwIVs) cause considerable morbidity and mortality in domestic pigs, resulting in a significant economic burden. Moreover, pigs have been considered to be a possible mixing vessel in which novel strains loom. Here, we developed and evaluated a novel M2e-multiple antigenic peptide (M2e-MAP) as a supplemental antigen for inactivated H3N2 vaccine to provide cross-protection against two main subtypes of SwIVs, H1N1 and H3N2. The novel tetra-branched MAP was constructed by fusing four copies of M2e to one copy of foreign T helper cell epitopes. A high-yield reassortant H3N2 virus was generated by plasmid based reverse genetics. The efficacy of the novel H3N2 inactivated vaccines with or without M2e-MAP supplementation was evaluated in a mouse model. M2e-MAP conjugated vaccine induced strong antibody responses in mice. Complete protection against the heterologous swine H1N1 virus was observed in mice vaccinated with M2e-MAP combined vaccine. Moreover, this novel peptide confers protection against lethal challenge of A/Puerto Rico/8/34 (H1N1). Taken together, our results suggest the combined immunization of reassortant inactivated H3N2 vaccine and the novel M2e-MAP provided cross-protection against swine and human viruses and may serve as a promising approach for influenza vaccine development.

X-Ray crystal structure of [HSm{V^IVO(TPPS)}]_<i>n</i> and encapsulation of nitrogen molecules in 1-D channels

Chen, Wen-Tong,Yamada, Yusuke,Liu, Guang-Ning,Kubota, Akira,Ichikawa, Takayuki,Kojima, Yoshitsugu,Guo, Guo-Cong,Fukuzumi, Shunichi Royal Society of Chemistry 2011 Dalton transactions Vol.40 No.48

<P>The crystal structure of an N<SUB>2</SUB>-encapusulated MOF, which is stable under open-air conditions at ambient temperature, was determined by single-crystal X-ray diffraction at 123 K. The crystal MOF of [HSm{V<SUP>IV</SUP>O(TPPS)}]<SUB><I>n</I></SUB> designed to have 1-D channels periodically constricted by porphyrins planes adsorbed N<SUB>2</SUB> at 77 K. The adsorbed N<SUB>2</SUB> molecules remained in the 1-D channels even after warming to ambient temperature. The single-crystal structure of [HSm{V<SUP>IV</SUP>O(TPPS)}]<SUB><I>n</I></SUB>⊃N<SUB>2</SUB> determined by X-ray diffraction indicated that N<SUB>2</SUB> molecules trapped in the constricted parts block other N<SUB>2</SUB> molecules in 1-D channels from escaping from the MOF. Such a unique encapsulation mode provides a promising approach toward designing novel MOFs with high gas storage capacity at ambient temperature.</P> <P>Graphic Abstract</P><P>The shrinking of a channel window to fit the size of stopper molecules enables encapsulation of adsorbates in the 1-D channels. <IMG SRC='http://pubs.rsc.org/services/images/RSCpubs.ePlatform.Service.FreeContent.ImageService.svc/ImageService/image/GA?id=c1dt10956a'> </P>

Magnetic and Optical Studies of Hydrogenated Cu-doped ZnO Film

Tong Li,Wen Xiao,Tun Seng Herng,Nina Bao,Jun Ding 한국물리학회 2013 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.62 No.12

Significantly enhanced ferromagnetism and strong green emission were observed for Cu-dopedZnO films undergoing a hydrogenation process. After H2 treatment at 500 C, the saturation magnetizationof 2 at% Cu-doped ZnO film (50 nm) is significantly increased from 1.65 emu cm−3(0.3 µB/Cu) to 11.7 emu cm−3 (1.5 µB/Cu). The areal magnetization of the hydrogenated CudopedZnO is dependent on the film thickness, thus suggesting that it is Cu dopants that playdominant roles rather than surface magnetism arising from OH attachment. Detailed XPS and Ramananalysis demonstrated that H2 treatment may introduce more Cu (Cu1+ -like) impurities andoxygen vacancies that coupled with each other, resulting in ferromagnetic ordering. Furthermore,strong green emission can be obtained in hydrogenated Cu-doped ZnO films. The green emissionis unlikely related with Cu dopants, but H2 treatment can generate a unique structure with porousmorphology and coexistence of complex defects that favors the green emission. The “green defects”are not simple O vacancies or H-incorporation and are stable after annealing at 700 C underO2 atmosphere. The high room temperature ferromagnetism and strong green light emission ofhydrogenated Cu-doped ZnO film pave a way to its novel applications in future spintronics andoptoelectronic devices.

Chemical Composition and Antimicrobial Efficacy of Helminthostachys zeylanica against Foodborne Bacillus cereus

Tong Woei Yenn,Leong Chean Ring,Khairul Azly Zahan,Muhammad Sharir Abdul Rahman,Wen-Nee Tan,Bintul Jauza’ Shaik Alaudin 한국생약학회 2018 Natural Product Sciences Vol.24 No.1

Helminthostachys zeylanica is a rare plant grows in lightly shaded areas. The fern was traditionally used as antipyretic and antiphlogistic agents. This study was aimed to evaluate the antibacterial potential of H. zeylanica on foodborne Bacillus cereus. The chemical composition of its ethanolic extract was also determined. The plant samples were collected at Kampung Kebun Relong, Kedah, Malaysia. The ethanolic extract showed significant inhibitory activity on B. cereus with a sizeable clear zone detected on disc diffusion assay. On broth microdilution assay, the MIC of the extract on B. cereus was 6.25 mg/ml and the MBC was 12.5 mg/ml. The inhibitory activity of the extract on B. cereus was bactericidal. In the growth dynamic study, the antibacterial efficacy of the extract was concentration dependent, where a lower colony forming unit count was obtained with increased extract concentration. The SEM micrograph of extract treated B. cereus cells showed invaginations of cell wall. The bacterial cell structure collapsed after 24 h exposure to the extract. The GCMS analysis of the extract showed that the major constituents of the extract were phenol (36.26%) and quercetin (29.70%). This study is important as it shows the potential use of H. zeylanica as an effective agent to control B. cereus related infections.

Film condensation on horizontal tube with wall suction effects

Tong-Bou Chang,Wen-Yu Yeh,Go-Long Tsai 대한기계학회 2009 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.23 No.12

This study performs a theoretical investigation into the problem of two-dimensional steady filmwise condensation flow on a horizontal tube with suction effects at the tube surface. An effective suction function is introduced to model the effect of the wall suction on the thickness of the liquid condensate film. The local condensate film thickness and the local Nusselt number are then derived using a simple series numerical method. The results show that the Nusselt number varies as a function of the Jakob number Ja, the Rayleigh number Ra, and the suction parameter Sw. It is found that the wall suction effect has a significant influence on the heat transfer performance. An analytical solution is derived for the mean Nusselt number for the case in which the wall suction effect is ignored. Finally, a closed-form correlation is presented for the mean Nusselt number subject to a wall suction effect.