ABSTRACTS ; TRENDS IN MOLECULAR BIOLOGY : HUMAN GENOME PROJECT AND APPLICATIONS

Mathias Uhlen 한국생화학분자생물학회 (구 한국생화학회) 1995 추계학술대회집 Vol.- No.-

Composite Behaviour of Textile Reinforced Reactive Powder Concrete Sandwich Façade Elements

Mathias Flansbjer,Natalie Williams Portal,Daniel Vennetti,Urs Mueller 한국콘크리트학회 2018 International Journal of Concrete Structures and M Vol.12 No.7

Within the EC funded project smart elements for sustainable building envelopes, carbon textile reinforcement was incorporated into reactive powder concrete, namely textile reinforced reactive powder concrete (TRRPC), to additionally improve the post-cracking behaviour of the cementitious matrix. This high-performance composite material was included as outer and inner façade panels in prefabricated and non-load bearing sandwich elements along with low density foamed concrete (FC) and glass fibre reinforced polymer continuous connecting devices. Experiments and finite element analysis (FEA) were applied to characterize the structural performance of the developed sandwich elements. The mechanical behaviour of the individual materials, components and large-scale elements were quantified. Four-point bending tests were performed on large-scale TRRPC-FC sandwich element beams to quantify the flexural capacity, level of composite action, resulting deformation, crack propagation and failure mechanisms. Optical measurements based on digital image correlation were taken simultaneously to enable a detailed analysis of the underlying composite action. The structural behaviour of the developed elements was found to be highly dependent on the stiffness and strength of the connectors to ensure composite action between the two TRRPC panels. As for the FEA, the applied modelling approach was found to accurately describe the stiffness of the sandwich elements at lower load levels, while describing the stiffness in a conservative manner after the occurrence of connector failure mechanisms.

Real Time ECG Monitoring Through a Wearable Smart T-shirt

Mathias, Dakurah Naangmenkpeong,Kim, Sung-Il,Park, Jae-Soon,Joung, Yeun-Ho The Korean Institute of Electrical and Electronic 2015 Transactions on Electrical and Electronic Material Vol.16 No.1

A wearable sensing ECG T-shirt for ubiquitous vital signs sensing is proposed. The sensor system consists of a signal processing board and capacitive sensing electrodes which together enable measurement of an electrocardiogram (ECG) on the human chest with minimal discomfort. The capacitive sensing method was employed to prevent direct ECG measurement on the skin and also to provide maximum convenience to the user. Also, low power integrated circuits (ICs) and passive electrodes were employed in this research to reduce the power consumption of the entire system. Small flexible electrodes were placed into cotton pockets and affixed to the interior of a worn tight NIKE Pro combat T-shirt. Appropriate signal conditioning and processing were implemented to remove motion artifacts. The entire system was portable and consumed low power compared to conventional ECG devices. The ECG signal obtained from a 24 yr. old male was comparable to that of an ECG simulator.

Awareness of Reproductive Health Risks, Sex Hormone Levels and Sperm Indices among Farmers Exposed to Pesticides in Akungba Akoko, Nigeria

Mathias Abiodun Emokpae,Evelyn Apiriboh Yeiya,Mathias Abiodun Emokpae 한국환경보건학회 2022 한국환경보건학회지 Vol.48 No.4

Background: The indiscriminate use of pesticides in Nigeria may have harmful effects on reproductive health of farmers. Objectives: This study assessed the awareness of reproductive health, serum follicle stimulating hormone (FSH), luteinizing hormone (LH), testosterone, estradiol, progesterone and sperm characteristics of male farmers occupationally exposed to pesticides. Methods: Eighty four male farmers were recruited for the study. Structured questionnaire was used to obtain the socio-demographic data. Blood and semen samples were collected from the subjects in the morning for hormonal assays and semen analysis using enzyme linked immunosorbent assay (ELISA) method and SQAV sperm quality analyzer. Data were analyzed using chi square, Student's-t-test, and Regression analysis. Results: Serum FSH (p<0.01), LH (p<0.005) and Estradiol (p<0.001) were significantly higher while prolactin (p<0.02) and testosterone (p<0.001) were significantly lower among pesticides exposed farmers than non- exposed subjects. Some 34/84 (40.5%) of the pesticides exposed farmers had serum testosterone levels below the lower limit of the reference range. Those with low testosterone levels (p<0.001), also had FSH (p<0.05), LH (p<0.001) and Estradiol (p<0.002) significantly lower than those with normal testosterone levels. The sperm count among pesticides exposed farmers; total motility and percentage morphology were significantly lower than non-pesticides exposed subjects. Some 14/84 (16.7%) of the pesticides exposed farmers had sperm count below 15 million/mL (oligozoospermia). More than 70% of the farmers were not aware of the reproductive health risks associated with pesticides and only 23.8% of the farmers were using protective devices. Conclusions: Deliberate efforts to improve awareness, knowledge, personal hygiene, and interventions necessary to lessen both pesticides exposure and health risks by adopting safe practices are suggested.

System identification of circadian clock in plant Arabidopsis thaliana

Mathias Foo,Hee Young Yoo,Pan-Jun Kim 제어로봇시스템학회 2013 제어로봇시스템학회 국제학술대회 논문집 Vol.2013 No.10

The use of mathematical models in describing the dynamics of circadian clock in the plant Arabidopsis thaliana is gaining popularity. Models used to describe the plant circadian clock are usually derived from laws of physics and they comprise complex nonlinear ordinary differential equations. In this paper, we build mathematical models of the core loop of plant circadian clock using system identification techniques. This core loop involves two main genes (proteins), i.e. LHY/CCA1 and TOC1. Models obtained using system identification techniques are usually simple, sufficient to describe the relevant dynamics of the system and often are able to provide physical interpretation about the system. The obtained models through system identification can be useful for control design and prediction in the event for which we want to do phenotype manipulation and for understanding the behaviour of the system respectively.

Tribological conditions using CO2 as volatile lubricant in dry metal forming

Mathias Liewald,Günter E. M. Tovar,Christoph Woerz,Georg Umlauf 한국정밀공학회 2020 International Journal of Precision Engineering and Vol.7 No.5

Deep drawing is the most important manufacturing process in order to produce sheet metal parts in mass production. In this study, volatile carbon dioxide (CO 2) is used as lubricant in order to replace mineral oil-based lubricants. CO 2 is injected into the void between the forming tool and the metal part through laser drilled microholes in the forming tool and acts there as a highly efficient lubricant. In order to investigate the tribological conditions during the drawing process, a new test bench having optical access to the CO 2 lubricant is designed, built and used in this study. Additionally, the CO 2 fl ow through the microholes is modeled using CFD simulation. Both the experimental and the theoretical study reveal a critical influence of the geometry of the microholes on the phase of the CO 2 in the forming tool and on the friction during the drawing process. Thereby, these investigations confirm that the CO 2 is in solid and/or gaseous state dependent on the surface pressure and the geometry of the microholes. Consequently, these results support the concept of microstructure-designed forming tools allowing dry metal forming for locally adjusted and environmentally friendly friction conditions.

Has Consumption Risk Sharing Increased in Asia (and Elsewhere)?

Mathias Hoffmann 서울대학교 경제연구소 2011 Seoul journal of economics Vol.24 No.4

What impact has financial globalization had on risk sharing? In theory, financial globalization should improve international consumption risk sharing. While the answer to this question is of utmost policymaking concern, results in the empirical literature are inconclusive. The paper surveys the extant literature and tries to identify which factors influence the answer: i) consumption risk sharing seems to have increased among industrialized countries but much less in the emerging world. ii) The increase in risk sharing is generally found to be stronger in studies that focus on the trends rather than purely cyclical variation in the data. iii) globalization has not only affected consumption responses to output shocks but also the structure of these shocks themselves. This, in turn, has affected the measurement of risk sharing. The paper examines the relevance of these points on a sample of East Asian Economies. My results indicate that risk sharing in East Asia has started to increase once the region had recovered from the Asian crisis.

Development of a Novel Noncontact ECG Electrode by MEMS Fabrication Process

Mathias, Dakurah Naangmenkpeong,Park, Jaesoon,Kim, Eungbo,Joung, Yeun-Ho The Korean Institute of Electrical and Electronic 2016 Transactions on Electrical and Electronic Material Vol.17 No.3

Contact electrodes pose threats like inflammation, metal poisoning, and allergic reaction to the user during long term ECG procedure. Therefore, we present a novel noncontact electrocardiographic electrode designed through microelectromechanical systems (MEMS) process. The proposed ECG electrode consists of small inner and large outer circular copper plates separated by thin insulator. The inner plate enables capacitive transduction of bio-potential variations on a subject’s chest into a voltage that can be processed by a signal processing board, whereas the outer plate shields the inner plate from environmental electromagnetic noise. The electrode lead wires are also coaxially designed to prevent cables from coupling to ground or electronic devices. A prototype ECG electrode has an area of about 2.324 cm², is very flexible and does not require power to operate. The prototype ECG electrode could measure ECG at about 500 um distance from the subject’s chest.

Interplay of Structural Distortions, Dielectric Effects and Magnetic Order in Multiferroic GdMnO3

Mathias Doerr,Michael Loewenhaupt,Aditya A. Wagh,P. S. Anil Kumar,Suja Elizabeth,Sahana Roessler,Martin Rotter,Steffen Wirth 한국물리학회 2013 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.62 No.10

Multiferroic materials are characterized by simultaneous magnetic and ferroelectric ordering making them good candidates for magneto-electrical applications. We conducted thermal expansion and magnetostriction measurements in magnetic fields up to 14 T on perovskitic GdMnO3 by highresolution capacitive dilatometry in an effort to determine all longitudinal and transversal components of the magnetostriction tensor. Below the ordering temperature TN = 42 K, i.e., within the different complex (incommensurate or complex) antiferromagnetic phases, lattice distortions of up to 100 ppm have been found. Although no change of the lattice symmetry occurs, the measurements reveal strong magneto-structural phenomena, especially in the incommensurate sinusoidal antiferromagnetic phase. A strong anisotropy of the magnetoelastic properties was found, in good agreement with the type and propagation vector of the magnetic structure. We demonstrate that our capacitive dilatometry can detect lattice expansion effects and changes of the dielectric permittivity simultaneously because the sample is housed inside the capacitor. A separation of both effects is possible by shielding the sample. Dielectric transitions could be detected by this method and compared to the critical values of H and T in the magnetic phase diagram. Dielectric changes measured at 1 kHz excitation frequency are detected in GdMnO3 at about 180 K,and between 10 K and 25 K in the canted antiferromagnetic structure which is characterized by a complex magnetic order on both the Gd- and Mn-sites.

SRV<SUP>®</SUP>-Testing of the Tribosystem Piston Ring and Cylinder Liner Outside the Engine

Mathias Woydt,Johannes Ebrecht 한국트라이볼로지학회 2005 KSTLE International Journal Vol.6 No.2

An OEM driven working group started in January 2004 to elaborate the philosophies, concepts and test procedures for testing piston ring and cylinder liner materials as well as engine oils outside the engine using the SRV<SUP>®</SUP> test equipment. The different SRV<SUP>®</SUP> test philosophies in use by OEMs are compiled. The working group focuses on a.) ASTM sequence VIB (Fuel economy by aging oils), b.) friction and wear in the top dead region under mixed/boundary lubrication, c.) extreme pressure load under mixed/boundary lubrication and d.) hydrodynamic friction. Tribological test results and precision data are presented.