Enhanced x-ray irradiation-induced cancer cell damage by gold nanoparticles treated by a new synthesis method of polyethylene glycol modification

Liu, Chi-Jen,Wang, Chang-Hai,Chien, Chia-Chi,Yang, Tsung-Yeh,Chen, Shin-Tai,Leng, Wei-Hua,Lee, Cheng-Feng,Lee, Kuen-Ho,Hwu, Y,Lee, Yao-Chang,Cheng, Chia-Liang,Yang, Chung-Shi,Chen, Y J,Je, J H,Margari IOP Pub 2008 Nanotechnology Vol.19 No.29

<P>We explored a very interesting gold nanoparticle system—pegylated gold in colloidal solution—and analyzed its uptake by mice colorectal adenocarcinoma CT26 tumor cells and the impact on the cell’s response to x-ray irradiation. We found that exposure to polyethylene glycol (PEG) modified (‘pegylated’) 4.7 ± 2.6 nm gold nanoparticles synthesized by a novel synchrotron-based method enhances the response of CT26 cells to x-ray irradiation. Transmission electron microscopy (TEM) and confocal microscopy revealed that substantial amounts of such nanoparticles are taken up and absorbed by the cells and this conclusion is supported by quantitative induced coupled plasma (ICP) results. Standard tests indicated that the internalized particles are highly biocompatible but strongly enhance the cell damage induced by x-ray irradiation. Synchrotron radiation Fourier transform infrared (SR-FTIR) spectromicroscopy analyzed the chemical aspects of this phenomenon: the appearance of C = O stretching bond spectral features could be used as a marker for cell damage and confirmed the enhancement of the radiation-induced toxicity for cells.</P>

Optical Resonant Cavity in a Nanotaper

Lee, Sang Hyun,Goto, Takenari,Miyazaki, Hiroshi,Chang, Jiho,Yao, Takafumi American Chemical Society 2010 NANO LETTERS Vol.10 No.6

<P>The present study describes an optical resonant cavity in a nanotaper with scale reduction from micro to several nanometers. Both experimental results and a finite-difference time-domain (FDTD)-based simulation suggested that the nanometer-scale taper with a diameter similar to the wavelength of light acted as a mirror, which facilitated the formation of a laser cavity and caused lasing in ZnO nanotapers. As the light inside the nanotaper propagated toward the apex, the lateral mode was reduced and reflection occurred. This report suggests that use of the resonant optical cavities in nanotapers might result in novel active and passive optical components, which will broaden the horizons of photonic technology.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/nalefd/2010/nalefd.2010.10.issue-6/nl100100z/production/images/medium/nl-2010-00100z_0003.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/nl100100z'>ACS Electronic Supporting Info</A></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/nl100100z'>ACS Electronic Supporting Info</A></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/nl100100z'>ACS Electronic Supporting Info</A></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/nl100100z'>ACS Electronic Supporting Info</A></P>

Leaf Vein-Inspired Nanochanneled Graphene Film for Highly Efficient Micro-Supercapacitors

Chang, Jian,Adhikari, Subash,Lee, Tae Hoon,Li, Bing,Yao, Fei,Pham, Duy Tho,Le, Viet Thong,Lee, Young Hee Wiley Blackwell (John Wiley Sons) 2015 ADVANCED ENERGY MATERIALS Vol.5 No.9

Induction of Forkhead Class box O3a and apoptosis by a standardized ginsenoside formulation, KG-135, is potentiated by autophagy blockade in A549 human lung cancer cells

Yao, Chih-Jung,Chow, Jyh-Ming,Chuang, Shuang-En,Chang, Chia-Lun,Yan, Ming-De,Lee, Hsin-Lun,Lai, I-Chun,Lin, Pei-Chun,Lai, Gi-Ming The Korean Society of Ginseng 2017 Journal of Ginseng Research Vol.41 No.3

Background: KG-135, a standardized formulation enriched with Rk1, Rg3, and Rg5 ginsenosides, has been shown to inhibit various types of cancer cells; however, the underlying mechanisms are not fully understood. In this study, we explored its effects in A549 human lung cancer cells to investigate the induction of Forkhead Class box O3a (FOXO3a) and autophagy. Methods: Cell viability was determined by sulforhodamine B staining. Apoptosis and cell cycle distribution were analyzed using flow cytometry. The changes of protein levels were determined using Western blot analysis. Autophagy induction was monitored by the formation of acidic vesicular organelles stained with acridine orange. Results: KG-135 effectively arrested the cells in G1 phase with limited apoptosis. Accordingly, a decrease of cyclin-dependent kinase-4, cyclin-dependent kinase-6, cyclin D1, and phospho-retinoblastoma protein, and an increase of p27 and p18 proteins were observed. Intriguingly, KG-135 increased the tumor suppressor FOXO3a and induced the accumulation of autophagy hallmark LC3-II and acidic vesicular organelles without an increase of the upstream marker Beclin-1. Unconventionally, the autophagy adaptor protein p62 (sequestosome 1) was increased rather than decreased. Blockade of autophagy by hydroxychloroquine dramatically potentiated KG-135-induced FOXO3a and its downstream (FasL) ligand accompanied by the cleavage of caspase-8. Meanwhile, the decrease of Bcl-2 and survivin, as well as the cleavage of caspase-9, were also drastically enhanced, resulting in massive apoptosis. Conclusion: Besides arresting the cells in G1 phase, KG-135 increased FOXO3a and induced an unconventional autophagy in A549 cells. Both the KG-135-activated extrinsic FOXO3a/FasL/caspase-8 and intrinsic caspase-9 apoptotic pathways were potentiated by blockade of autophagy. Combination of KG-135 and autophagy inhibitor may be a novel strategy as an integrative treatment for cancers.

MFN1 deacetylation activates adaptive mitochondrial fusion and protects metabolically challenged mitochondria

Lee, Joo-Yong,Kapur, Meghan,Li, Ming,Choi, Moon-Chang,Choi, Sujin,Kim, Hak-June,Kim, Inhye,Lee, Eunji,Taylor, J. Paul,Yao, Tso-Pang The Company of Biologists Ltd. 2014 Journal of cell science Vol.127 No.22

<P>Fasting and glucose shortage activate a metabolic switch that shifts more energy production to mitochondria. This metabolic adaptation ensures energy supply, but also elevates the risk of mitochondrial oxidative damage. Here, we present evidence that metabolically challenged mitochondria undergo active fusion to suppress oxidative stress. In response to glucose starvation, mitofusin 1 (MFN1) becomes associated with the protein deacetylase HDAC6. This interaction leads to MFN1 deacetylation and activation, promoting mitochondrial fusion. Deficiency in HDAC6 or MFN1 prevents mitochondrial fusion induced by glucose deprivation. Unexpectedly, failure to undergo fusion does not acutely affect mitochondrial adaptive energy production; instead, it causes excessive production of mitochondrial reactive oxygen species and oxidative damage, a defect suppressed by an acetylation-resistant MFN1 mutant. In mice subjected to fasting, skeletal muscle mitochondria undergo dramatic fusion. Remarkably, fasting-induced mitochondrial fusion is abrogated in HDAC6-knockout mice, resulting in extensive mitochondrial degeneration. These findings show that adaptive mitochondrial fusion protects metabolically challenged mitochondria.</P>

Ring-Type Rotary Ultrasonic Motor Using Lead-free Ceramics

( Chang Hyo Hong ),( Hyoung Su Han ),( Jae Shin Lee ),( Ke Wang ),( Fang Zhou Yao ),( Jing Feng Li ),( Jung Ho Gwon ),( Nguyen Van Quyet ),( Jin Kyung Jung ),( Wook Jo ) 한국센서학회 2015 센서학회지 Vol.24 No.4

Ultrasonic motors provide high torques and quick responses compared to their magnetic counterparts; therefore, they are widely used in small-scale applications such as mobile phones, microrobots, and auto-focusing modules in digital cameras. To determine the feasibility of lead-free piezoceramics for ultrasonic motor applications, we fabricated a ring-type piezoceramic with a KNN-based lead-free piezoceramic (referred to as CZ5), intended for use in an auto-focusing module of a digital camera. The vibration of the lead-free stator was observed at 45.1 kHz. It is noteworthy that the fully assembled lead-free ultrasonic motor exhibited a revolution speed of 5-7 rpm, even though impedance matching with neighboring components was not considered. This result suggests that the tested KNN-based piezoceramic has great potential for use in ultrasonic motor applications, requiring minimal modifications to existing lead-based systems.

Cathodoluminescence study of nonuniformity in hydride vapor phase epitaxy-grown thick GaN films

Lee, W.,Watanabe, K.,Kumagai, K.,Park, S.,Lee, H.,Yao, T.,Chang, J.,Sekiguchi, T. Oxford University Press 2012 Journal of electron microscopy Vol.61 No.1

A strategy to overcome the limits of carbon-based materials as lithium-ion battery anodes

Yao, F.,Li, B.,So, K.,Chang, J.,Ly, T.H.,Vu, A.Q.,Mun, H.,Cojocaru, C.S.,Yue, H.,Xie, S.,Lee, Y.H. Pergamon Press ; Elsevier Science Ltd 2014 Carbon Vol.79 No.-

The free-standing Si-coated carbon nanofiber (Si/CNF) mat was fabricated for the anode of lithium ion battery through combining electrospun CNF mat with electrodeposited Si layer. Spaghetti or granule-like Si was obtained by varying the deposition conditions. This Si/CNF mat was directly used as an active material and a current collector as well, which involves neither binders nor additional metal substrate. The best performance was achieved in spaghetti-like Si due to its highly porous nature which can accommodate volume expansion and large surface area which benefit the efficient charge transfer both at Si/CNF interface and at the electrode/electrolyte interface. The optimized Si/CNF mat after annealing at 1000<SUP>o</SUP>C delivered a capacity of 870mAhg<SUP>-1</SUP> at 1st discharge and 730mAhg<SUP>-1</SUP> at 50th discharge with a capacity retention of 84%, improving the capacity of pure CNF (280mAhg<SUP>-1</SUP> at the 50th discharge) by almost three times. In addition, corrosion of the current collector no longer exists in our approach. Our X-ray photoemission spectroscopy and electrochemical analysis revealed that the formation of Si-C bond through high temperature annealing can enhance the adhesion between silicon and carbon at the interface which benefits the cyclic performance of anode ultimately.

Recognition of Events by Human Motion for Context-aware Computing

최요환(Yao-Huan Cui),신성윤(Seong-Yoon Shin),이창우(Chang-Woo Lee) 한국컴퓨터정보학회 2009 韓國컴퓨터情報學會論文誌 Vol.14 No.4

최근 컴퓨터비젼 분야에서 이벤트 검출 및 인식이 활발히 연구되고 있으며, 도전적인 주제들 중 하나이다. 본 논문에서는 사무실 환경에서 발생할 수 있는 이벤트의 검출 및 인식을 위한 방법을 제안한다. 제안된 방법은 MHI(Motion History Image) 시퀀스(sequence)를 이응한 인간의 모션을 분석하며, 사람의 처형과 착용한 옷의 종류와 색상, 그리고 카메라로부터의 위치관계에 불변한 특성을 가진다. 제안된 방법은 기존의 방법들 중, 칼라 정보를 이용한 방법에 비해 조명의 변화에 민감하지 않은 장점이 있으며, 관심의 대상이 되는 객체의 외형과 같은 사전지식에 의존하는 방법에 비해 스케일에 민감하지 않은 장점이 있다. 에지검출 기술을 HMI 순서 영상 정보와 결합하여 사람 모션의 기하학적 특징을 추출한 후, 이벤트 인식의 기본정보로 활용한다. 제안된 방법은 단순한 이벤트 검출 프레임웍을 사용하기 때문에 검출하고자 하는 이벤트의 설명만을 첨가하는 것으로 확장이 가능하다. 또한, 제안된 방법은 컴퓨터비젼 기술에 기반한 많은 감시시스템 뿐 아니라 상황인식 기반의 이벤트 검출 시스템에 핵심기술이다. Event detection and recognition is an active and challenging topic recent in Computer Vision. This paper describes a new method for recognizing events caused by human motion from video sequences in an office environment. The proposed approach analyzes human motions using Motion History Image (MHI) sequences, and is invariant to body shapes. types or colors of clothes and positions of target objects. The proposed method has two advantages; one is thant the proposed method is less sensitive to illumination changes comparing with the method using color information of objects of interest, and the other is scale invariance comparing with the method using a prior knowledge like appearances or shapes of objects of interest. Combined with edge detection, geometrical characteristics of the human shape in the MHI sequences are considered as the features. An advantage of the proposed method is that the event detection framework is easy to extend by inserting the descriptions of events. In addition, the proposed method is the core technology for event detection systems based on context-aware computing as well as surveillance systems based on computer vision techniques.

Vision-based human motion analysis for event recognition

최요환(Yao-Huan Cui),이창우(Chang-Woo Lee) 한국컴퓨터정보학회 2009 한국컴퓨터정보학회 학술발표논문집 Vol.16 No.2

최근 컴퓨터비젼 분야에서 이벤트 검출 및 인식이 활발히 연구되고 있으며, 도전적인 주제들 중 하나이다. 이벤트 검출 기술들은 많은 감시시스템들에서 유용하고 효율적인 응용 분야이다. 본 논문에서는 사무실 환경에서 발생할 수 있는 이벤트의 검출 및 인식을 위한 방법을 제안한다. 제안된 방법에서의 이벤트는 입장( entering), 퇴장(exiting), 착석(sitting-down), 기립(standing-up)으로 구성된다. 제안된 방법은 하드웨어적인 센서를 사용하지 않고, MHI(Motion History Image) 시퀀스(sequence)를 이용한 인간의 모션 분석을 통해 이벤트를 검출할 수 있는 방법이며, 사람의 체형과 착용한 옷의 종류와 색상, 그라고 카메라로부터의 위치관계에 불변한 특성을 가진다. 에지검출 기술을 HMI 시퀀스정보와 결합하여 사람 모션의 기하학적 특징을 추출한 후, 이 정보를 이벤트 인식의 기본 특징으로 사용한다. 제안된 방법은 단순한 이벤트 검출 프레임웍을 사용하기 때문에 검출하고자 하는 이벤트의 설명만을 첨가하는 것으로 확장이 가능하다. 또한, 제안된 방법은 컴퓨터비견 기술에 기반한 많은 감시시스템에 적용이 가능하다.