여성에 있어서 경동맥 경직도와 심폐지구력 및 근력의 관계

한성유(Han, Seung-Yu),박진기(Park, Jin-Kee) 한국체육과학회 2019 한국체육과학회지 Vol.28 No.1

The aim of this study was investigate the relationship between muscle strength and cardiorespiratory fitness with carotid stiffness index in adults women. A total of 187 adult women(19-76yrs) participated in this study. In all subjects, muscle strength was measured by hand grip strength, and cardiorespiratory fitness were measured by multistage shuttle run test(≤59yrs) or two minutes steps test(≥60yrs). Carotid variables were measured with B-mode ultrasound. Independent t-test was performed to assess difference in the carotid stiffness variables between two groups, according to the level of muscle strength and cardiorespiratory fitness. In all subjects, the group with high muscle strength and low cardiorespiratory fitness showed significantly high carotid β-stiffness, but low carotid compliance. Analysis by age, the carotid β-stiffness and compliance were significantly different between the two groups according to muscle strength in young(19-39yrs) and middle(40-49yrs) age adults women. But, in old adults(≥ 60yrs) women, carotid β-stiffness and compliance were no different between two groups according to muscle strength. However, carotid β-stiffness and compliance were significantly different between the two groups according to cardiorespiratory fitness in all subjects. Therefore, higher cardiorespiratory fitness may have a beneficial effects on carotid stiffness index, but high muscle strength may have deleterious effects in adults women.

항복강도에 따른 Zr-2.5Nb 압력관의 Delayed Hydride Cracking Velocity

김영석,최승준,정용무,김인섭,마르켈로프 대한금속재료학회 2004 대한금속·재료학회지 Vol.42 No.1

The objective of this study is to investigate delayed hydride cracking velocity (DHCV) of Zr-2.5Nb pressure tubes with yield strength. DHC tests were conducted at an initial K_(I) of 15 to 19 MPa √m and 250℃ on the compact tension specimens containing up to 100 ppm hydrogen that were taken from the Zr-2.5Nb tubes with different yield strengths. The crack growth was determined with the direct current potential drop method. A nice correlation of the DHC velocity and the yield strength was obtained at all temperatures by normalizing the DHCV with the terminal solid solubility and diffusion of hydrogen: the DHCV increased exponentially with increased yield strength of the Zr- 2.5Nb tubes. In contrast, the texture and the distribution of the β-Zr phase were found to have a comparatively minor effect on the DHCV of the Zr-2.5Nb tubes. Yield strength of the Zr-2.5Nb tubes determines a plastic zone size with a steep gradient of hydrogen concentration ahead of the crack tip where hydrides can be precipitated. The yield strength effect is analyzed by correlating the plastic zone and the striation spacing observed on the fractured surfaces as a function of the yield strength.

2P-26 Preparation and Characterization of Glass-Ionomer Cements Using Modified Cyclodextrins

유은경,정일두,박기영 한국공업화학회 2017 한국공업화학회 연구논문 초록집 Vol.2017 No.1

GICs have relatively low mechanical strength such as tensile and flexural strength. To solve the mechanical properties, resin-modified glassionomer cements have been developed. Cyclodextrins have hydroxyl groups, 1 of primary hydroxyl group and 2 of secondary hydroxyl group per 1 glucose unit, which can be used chemical modification sites for varies application. In this study, β-cyclodextrin were modified by functionalities such as vinyl group and sulfonic acid or carboxylic acid. FT-IR, ¹H NMR, ¹³C NMR and MALDI-TOF were used for the characterization of the modified β- cylodextrin. Glass ionomer-cements(GICs) ware prepared by photopolymerizing the modified β-cylodextrin with conventional Fuji II LC glass. Finally experimental GICs formulated by cyclodextrin derivatives with vinyl group and carboxylic acid showed highest mechanical strengths such as compressive strength(CS), diamatral tensile strength(DTS) as well as better shrinkages and viscositie.

β-TCP 계 인공뼈 합성에 있어 나노 TCP 분말 첨가 영향

장명철,김태형,김욱규 한국생체재료학회 2013 생체재료학회지 Vol.17 No.3

CaO was obtained by calcining calcium carbonate (CaCO3) at 1050oC. For normal β-tricalcium phosphate (β-TCP) powders CaO and dicalcium phosphate (DCPA) were mixed at a molar ratio of 1:2 and calcined at 1050oC for 2hours.Nano-TCP powders were synthesized at 37oC by wet precipitation method using CaO and phosphoric acid. A certain percentage of nano-TCP powders were added into the normal β-TCP powders, and polystyrene (PS) beads were blended with the mixture to make a β-TCP block samples, which were sintered at 800-1150oC. The β-TCP block samples were investigated by means of SEM, XRD, micro-CT. With the amount of nano-TCP powders the mechanical strength of the artificial bone block was investigated by UTM [Universal Testing machine].The microstructure of the sintered block was three dimensionally ordered macro/micro pore architecture of beta-TCP phase from XRD and micro-CT measurement. The compressive strength of sintered block increased with the addition of nano-TCP powders. The nano-TCP powders were attached on the surface of macro β-TCP powders and the sample body was greatly toughened with the sintering process. The measured porosity of the sintered body was from 60% to 70%.

Mechanical properties and microstructures of β Ti-25Nb-11Sn ternary alloy for biomedical applications

Jung, T.K.,Semboshi, S.,Masahashi, N.,Hanada, S. Elsevier 2013 Materials science & engineering. C, Materials for Vol.33 No.3

The mechanical properties and microstructures of β Ti-25%Nb-11%Sn ternary alloy rods were investigated for biomedical applications as a function of heat treatment temperature after swaging by an 86% reduction in cross-section area. An as-swaged rod consisting of a β (bcc) single phase shows a low Young's modulus of 53GPa, which is interpreted in terms of both the metastable composition of the β alloy undergoing neither an athermal ω transformation nor a deformation-induced ω transformation and <110>texture development during swaging. Heat treatment at 673K (400<SUP>o</SUP>C) for 2h leads to a high strength of approximately 1330MPa and a high spring-back ratio of yield stress to Young's modulus over 15x10<SUP>-3</SUP>, with acceptable elongation. This high strength is attributable to needle-like α precipitates, which are identified by high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) and high-resolution electron microscopy (HREM).

β-Cyclodextrin을 사용한 새로운 Polyol 합성 및 낮은 열전도도와 높은 강도를 갖는 경질 PU Foam의 제조

박주한 ( Ju Han Park ),김태윤 ( Tae Yoon Kim ),김동호 ( Dong Ho Kim ),문진복 ( Jin Bok Moon ),정일두 ( Ll Doo Chung ) 한국접착및계면학회 2012 접착 및 계면 Vol.13 No.4

Although β-cyclodextrin (β-CD) has been used as medicine, agrichemical, food, cosmetic, antioxidant, anti-volatile agent, anti-hygroscopic agent, fading-protecting agent, and emulsifier due to its ability to form inclusion complex by enclosing another molecule (guest molecule), it has been restricted in practical application because of its low solubility in water and organic solvent. In this study, β-CD derivative as a new polyol with inclusion characteristics against Bisphenol A and cyclopropane, foaming agent for polyurethane (PU), and with improved solubility was synthesized, characterized and used to formulate rigid PU foam with better thermal conductivity and compressive strength compared to that from commercial polyols. β-cyclodextrin은 다른 분자를 포접하여 inclusion complex (포접착물)를 만드는 특성을 가지고 있기 때문에 의약품, 농약, 식품, 화장품, 산화방지제, 휘발방지제, 흡습방지제, 퇴색방지제, 유화제등의 다양한 용도로 사용되고 있다. 이러한 장점에도 불구하고 β-cyclodextrin은 물이나 유기용매에 대한 용해도가 낮아 사용에 제약을 받아왔다. 본 연구에서는 이러한 문제를 해결하기 위해서 Bisphenol-A나 폴리우레탄(PU) 발포제인 cyclopropane에 대한 포접특성을 갖고 물이나 유기용매에 대한 용해도가 향상된 polyol type의 β-cyclodextrin 유도체를 합성한 후 그 특성을 고찰하였다. 연구결과 합성된 polyol을 사용해서 제조한 경질 PU foam은 기존의 polyol과 비교해서 더 우수한 열전도 특성과 압축강도를 나타내었다.

유전자조작, 균주분리 Bacillus stearothermophilus No. 236 β-xylosidase 유전자 변이 promoter의 Strength 분석

김미동 ( Mi Dong Kim ),최용진 ( Yong Jin Choi ) 한국미생물생명공학회 2003 한국미생물·생명공학회지 Vol.31 No.2

Decorin이 굴곡건 치유시 인장강도에 미치는 영향

정지원,김형수 大韓成形外科學會誌 2000 Archives of Plastic Surgery Vol.27 No.1

Adhesion formed between tendon and its sheath after repair often impairs functional recovery. There have been many attempts to reduce adhesion around a repaired tendon, but most results have been unsatisfactory or impractical in clinical application. Moreover, most attempts were focused on extrinsic tendon healing. whereas studies on the intrinsic tendon healing are sacrce in the literature. We have previously reported that fibrotic tendon adhesion after repair was decreased by decorin, a natural inhibitor of TGF-β. Accordingly, the serial tensile strength was measured after complete tensection and repair of the tendon severance in order to confirm the effect of decorin inhibition of intrinsic healing capability. Forty White Leghorn chickens were subject to complete transection and repair of the third toe flexor digitorum profundus tendon in Zone Ⅱ. In the experimental group, 0.5ml of diluted decorin(50㎍/ml) was injected around the repaired site, and the same volume of saline solution in the control group. Tendons were harvested at 1, 3, 5 and 7 weeks. The disrupting force of the repair site was analyzed using tensiometry(LLOYD LR 30K, U.K). The tensile strength of repaired tendon was similar in both groups for all postoperative periods. This indicates that intrinsic healing proceeds normally within the decorin group in spite of the blockade of TGF-βactivity. Decorin, a natural inhibitor of TGF-β, showed a significant inhibitory effect on reducing post-repair tendon adhesions, without disruption of intrinsic healing in the chicken flexor tendon injury model. Therefore, decorin is expected to be a useful agent for preventnion on tendon adhesion after the repair in clinical usage.

베타알라닌 섭취가 중장거리 여자 사이클 선수의등속성 슬관절 근기능 및 경기기록에 미치는 영향

이영화 ( Yeong-hwa Lee ),전영경 ( Young-kyeong Jeon ),노대성 ( Dae-sung Rho ),서태범 ( Tae-beom Seo ) 한국스포츠정책과학원(구 한국스포츠개발원) 2016 체육과학연구 Vol.27 No.3

본 연구는 8주간의 베타알라닌 섭취가 중장거리 여자사이클 선수의 등속성 슬관절 근기능 및 경기기록에 미치는 효과를 검증하는 데 목적이 있다. 연구 대상자는 여자 사이클 선수 8명을 선정하였으며, 베타알라닌 섭취집단(Training group with beta-alanine ingestion, TB) 4명과 위약섭취집단(Training group with placebo ingestion, TP) 4명으로 무작위 분류하였다. 고강도 복합훈련과 함께 8주 동안 1일 3회씩 베타알라닌 및 위약의 섭취가 진행되었다. 운동수행능력을 평가하기 위해 사전·사후에 등속성 슬관절 근기능과 3km 경기기록 측정을 시행하였다. 집단과 측정시기에 따른 변인들의 변화량을 비교·분석하였으며 다음과 같은 결과를 얻었다. 등속성 근력의 경우, 좌우측 60°/sec 굴근 근력, 좌우측 180°/sec 신근 근력, 우측 180°/sec 굴근 근력 에서 집단과 시점 간에 상호작용이 나타났다. 3km 기록의 경우 집단과 시점간의 상호작용이 나타났다. 결론적으로 베타알라닌 섭취는 운동수행능력 및 경기기록 향상에 기여할 것으로 생각된다. The purpose of this study was to examine whether β-alanine ingestion for 8 weeks can regulate isokinetic knee strength, and 3km record in middle-long distance woman cyclists. Fourteen middle-long woman cyclists participated in this study and were divided into two groups; training group with beta-alanine ingestion and training group with placebo ingestion. All subjects took in beta-alanine or placebo supplement three times per a day for 8 weeks. Physical activity was evaluated by measuring the isokinetic muscular strength and 3km record before and after intervention for 8 weeks. As a results, in isokinetic test, there were significant interrelationships in peak torque of the right and left flexors at 60°/sec, peak torque of the right and left extensors at 180°/sec, peak torque of the right flexors at 180°/sec. In 3km record, result showed a significant interrelationship by groups and time. The results of present study provide evidence that beta-alanine supplement may be effective to increase physical activity and competition record in middle-long woman cyclists.

Construction of Optimal System for Efficient Agarose Degradation in Saccharomyces cerevisiae

Yu Na LEE,Won Kyung KIM,Yo Han JANG,Yeon Hee KIM 한국생물공학회 2023 한국생물공학회 학술대회 Vol.2023 No.10