• Title/Summary/Keyword: Science Programme

Search Result 244, Processing Time 0.022 seconds

GLOBAL CONVERGENCE PROPERTIES OF TWO MODIFIED BFGS-TYPE METHODS

  • Guo, Qiang;Liu, Jian-Guo
    • Journal of applied mathematics & informatics
    • /
    • v.23 no.1_2
    • /
    • pp.311-319
    • /
    • 2007
  • This article studies a modified BFGS algorithm for solving smooth unconstrained strongly convex minimization problem. The modified BFGS method is based on the new quasi-Newton equation $B_k+1{^s}_k=yk\;where\;y_k^*=yk+A_ks_k\;and\;A_k$ is a matrix. Wei, Li and Qi [WLQ] have proven that the average performance of two of those algorithms is better than that of the classical one. In this paper, we prove the global convergence of these algorithms associated to a general line search rule.

UNESCO와 과학문헌정보활동(科學文獻情報活動)

  • Lorch, Walter T.
    • Journal of Information Management
    • /
    • v.2 no.3
    • /
    • pp.2-4
    • /
    • 1964
  • Scientific documentation is one of the three preconditions for scientific research and its technical application in the industrialization process. To solve the documentation problems on an international level, UNESCO promotes abstracting, standardization of terminology and of scientifc publications, automatic information processing and translating. Moreover, UNESCO has helped to establish since 1950, on the request of interested national governments, 12 documentation centers within the framework of United Nations Technical Assistance Programme by providing experts, fellowships and equipment. Some data on these documentation centers and a comparison of their features should be of interest for all those who wish to set up new documentation centers or to improve already existing ones.

  • PDF

Effective Control of Stiffness of Tungsten Probe for AFM by Electrochemical Etching (전기화학적 에칭에 의한 AFM용 텅스텐 탐침의 강성 제어)

  • Han, Guebum;Lee, Seungje;Ahn, Hyo-Sok
    • Tribology and Lubricants
    • /
    • v.30 no.4
    • /
    • pp.218-223
    • /
    • 2014
  • This paper presents a method of controlling the stiffness of a tungsten probe for an atomic force microscope (AFM) in order to provide high-quality phase contrast images in accordance with sample characteristics. While inducing sufficient deformation on sample surfaces with commercial Si or $Si_3N_4$ probes is difficult because of their low stiffness, a tungsten probe fabricated by electrochemical etching with appropriately high stiffness can generate relatively large elastic deformation without damaging sample surfaces. The fabrication of the tungsten probe involves two separate procedures. The first procedure involves immersing a tungsten wire with both ends bent parallel to the surface of an electrolyte and controlling the stiffness of the tungsten cantilever by decreasing its diameter using electrochemical etching in the direction of the central axis. The second procedure involves immersing the end of the etched tungsten cantilever in the direction perpendicular to the surface of the electrolyte and fabricating a tungsten tip with a tip radius of 20-50 nm via the necking phenomenon. The latter etching process applies pulse waves every 0.25 seconds to the manufactured tip to improve its yield. Finite element analysis (FEA) of the stiffness of the tungsten probe as a function of its diameter showed that the stiffness of the tungsten probes greatly varies from 56 N/m to 3501 N/m according to the cantilever diameters from $30{\mu}m$ to $100{\mu}m$, respectively. Thus, the proposed etching method is effective for producing a tungsten probe having specific stiffness for optimal use with an AFM and certain samples.

Potential Chemoprevention Activity of Pterostilbene by Enhancing the Detoxifying Enzymes in the HT-29 Cell Line

  • Harun, Zaliha;Ghazali, Ahmad Rohi
    • Asian Pacific Journal of Cancer Prevention
    • /
    • v.13 no.12
    • /
    • pp.6403-6407
    • /
    • 2012
  • Detoxifying enzymes are present in most epithelial cells of the human gastrointestinal tract where they protect against xenobiotics which may cause cancer. Induction of examples such as glutathione S-transferase (GST) and its thiol conjugate, glutathione (GSH) as well as NAD(P)H: quinoneoxidoreductase (NQO1) facilitate the excretion of carcinogens and thus preventing colon carcinogenesis. Pterostilbene, an analogue of resveratrol, has demonstrated numerous pharmacological activities linked with chemoprevention. This study was conducted to investigate the potential of pterostilbene as a chemopreventive agent using the HT-29 colon cancer cell line to study the modulation of GST and NQO1 activities as well as the GSH level. Initially, our group, established the optimum dose of 24 hours pterostilbene treatment using MTT assays. Then, effects of pterostilbene ($0-50{\mu}M$) on GST and NQO1 activity and GSH levels were determined using GST, NQO1 and Ellman assays, respectively. MTT assay of pterostilbene ($0-100{\mu}M$) showed no cytotoxicity toward the HT-29 cell line. Treatment increased GST activity in the cell line significantly (p<0.05) at 12.5 and $25.0{\mu}M$. In addition, treatment at $50{\mu}M$ increased the GSH level significantly (p<0.05). Pterostilbene also enhanced NQO1 activity significantly (p<0.05) at $12.5{\mu}M$ and $50{\mu}M$. Hence, pterostilbene is a potential chemopreventive agent capable of modulation of detoxifiying enzyme levels in HT-29 cells.

A Study on the Academic Self-efficacy of Trainees Receiving the 4 Category-Union Education of HIT(Health Integrated Technic) (보건통합교육(HIT)의 4단계 융합교육이 학업적 자기효능감에 미치는 정도에 관한 연구)

  • Lee, Jae-Hong;Kim, Han-Soo;Park, Eun-Mi;Choe, Han-Seong;Jeong, Jin-Woo;Lee, Jae-Kwang;Kim, Seong-Joon;Kwon, Won-An
    • Journal of Korean Physical Therapy Science
    • /
    • v.21 no.1
    • /
    • pp.65-77
    • /
    • 2014
  • Purpose : This research is to understand the academic self-efficacy of trainees receiving the 4 category-union education of HIT(Health Integrated Technic) Methods : A self-administered questionnaire survey was conducted in 450 health-related college students in Daegu city from April to July. A statistical analysis was performed using SPSS 17.0 for window version. Results : First, satisfaction to education of HIT was higher in vocational consciousness program than patient care programme educational deepening program. Second, academic self-efficacy to education of HIT was higher in educational deepening program than patient care programme vocational consciousness program. Conclusion : Systemic education is needed to develop vocational consciousness, patient care and educational deepening that suit the characteristics of college students in order to establish an environment for revitalizing satisfaction and academic self-efficacy to 4 category-union education

  • PDF

Biosafety and Biosecurity Programme: Its Implementation, Requirements and Continuous Development at the Nanyang Technological University in Singapore

  • Tun, Tin;Preiser, Peter Rainer
    • Korean Journal of Clinical Laboratory Science
    • /
    • v.50 no.2
    • /
    • pp.77-84
    • /
    • 2018
  • In Singapore, biosafety and biosecurity measures are controlled by the Biological Agents and Toxins Act (BATA) and other requirements by regulatory agencies. The law prohibits and otherwise regulates the possession, use, import, transhipment, transfer, and transportation of biological agents, inactivated biological agents, and toxins that are of public health concern. The law also defines the facility requirements for high risk biological agents and toxins. The containment facility (BSL 3) is a minimum requirement to handle biological agents that falls under Schedule 1 (Risk Group 3). The Nanyang Technological University School of Biological Sciences Biosafety Level 3 Facility (NTU-SBS BSL 3) was designed specifically for research involving potential hazardous biological materials. The facility requires yearly re-certification by an approved facility certifier to meet the local requirements and international biosafety standards for a containment facility in many instances. On the other hand, most NTU researchers conduct biological projects involving biological agents with low or moderate risk groups (Risk Groups 1 and 2 or biological agents described in schedule 3 and 4 of BATA) and GMOs, which need only a BSL 2 laboratory. BSL 2 laboratories are yet to be legally certified or registered in Singapore. Institutional Biosafety Committee (IBC) identifies the requirements; defines a minimum standard in the safe control of biological risks and registers all BSL 2 laboratories in the NTU. Therefore, under the guidance of the IBC, the University Biosafety and Biosecurity Programme includes the audit and certification program as a unique and an internal exercise to bring NTU biosafety to a higher level.

Components in Commercial Douchi-a Chinese Fermented Black Bean Product by Supercritical Fluid Extraction

  • Kim, Joo-Shin;Chung, Hau-Yin
    • Preventive Nutrition and Food Science
    • /
    • v.13 no.1
    • /
    • pp.12-17
    • /
    • 2008
  • Douchi, a popular seasoning agent in Chinese dishes prepared by the Aspergillus oryzae fermentation of black beans, was subjected to supercritical fluid extraction (SFE) and gas chromatography-mass spectrometry analysis for its volatile components. A total of 73 components were identified in two commercial brands, which were positively confirmed and quantified. Among the common components in the two brands were 18 acids, 12 alcohols, 11 aldehydes, 9 esters, 1 furan, 11 other oxygen-containing compounds, 4 pyrazines, 2 pyridines and 5 miscellaneous compounds. The most abundant components found were acetic acid, benzoic acid, 2,6-dimethylpyrazine, 2-piperidinone, 3-methylbutanoic acid, maltol, 4-ethylphenol, 2-methylpropanoic acid, butanoic acid, 2-pyrrolidinone, all fatty acids and some esters.

Characterization of Volatile Components in Field Bean (Dolichos lablab) Obtained by Simultaneous Steam Distillation and Solvent Extraction

  • Kim, Joo-Shin;Chung, Hau-Yin
    • Preventive Nutrition and Food Science
    • /
    • v.13 no.1
    • /
    • pp.18-22
    • /
    • 2008
  • Volatile components in field bean (Dolichos lablab) were collected by simultaneous steam distillation and solvent extraction and analyzed by gas chromatography-mass spectrometry. One hundred and five components were identified including alcohols (32), ketones (18), aldehydes (9), acid (1), alkanes (5), aromatics compounds (4), esters (2), furans (2), naphthalene (1), pyrazines (4), pyridine (3), sulfur-containing compounds (4) and terpenes (7) and miscellaneous compounds (13). Relatively high concentration of n-hexanal found in the field bean might be undesirable to some consumers.

Measurement of Denitrification Rates in Groundwater: a collaborative New Zealand - Korean initiative

  • Close, Murray;Park, Jae-Woo;Dann, Rod;Flintoft, Mark;Burbery, Lee;Hadfield, John
    • Proceedings of the Korea Water Resources Association Conference
    • /
    • 2009.05a
    • /
    • pp.2205-2209
    • /
    • 2009
  • Nitrate contamination of groundwater is a wide-spread problem in both New Zealand and South Korea and has lead to eutrophication of receiving lakes and rivers. Denitrification in groundwater has the potential to reduce inputs of N to these receiving waters but quantification of the amount of denitrification taking place is difficult. A series of denitrification measurements have been carried out in the field at selected groundwater locations in New Zealand using a recently developed re-circulating well technique to increase sensitivity. This is an ongoing project and the methodology and sites are described and some preliminary results discussed. An overview of the collaborative research programme on in-situ groundwater processes (in which this denitrification project is a component) is provided.

  • PDF