• Title/Summary/Keyword: Premature Failure

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Association with Autoimmune Disease in Patients with Premature Ovarian Failure (조기 난소기능 부전증 환자에서 자가면역 질환과의 상관관계)

  • Park, Joon-Cheol;Kim, Jong-In;Rhee, Jeong-Ho
    • Clinical and Experimental Reproductive Medicine
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    • v.31 no.3
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    • pp.149-154
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    • 2004
  • Objective: To assess the association with autoimmune endocrine diseases and detection rate of autoimmune antibodies and its clinical significance in patients with premature ovarian failure. Methods: Twenty eight patients with primary or secondary amenorrhea manifesting hormonal and clinical features of premature ovarian failure (primary POF: 7, secondary POF: 21) were investigated. We tested them TFT, 75 g OGTT, ACTH and S-cortisol for thyroiditis, IDDM, Addison's disease, and antithyoglobulin antibody, antimicrosomal antibody, antinuclear antibody, rheumatic factor, anti-smooth muscle antibody, anti-acetylcholine receptor antibody for non-organ specific autoimmune disorders. Results: Only one patient was diagnosed as IDDM and no patients had abnormal TFT or adrenal function test. More than one kind of autoantibody was detected in 11 patients of all (39.2%): 5 patients (71.4%) of primary POF group and 6 patients (21.4%) of secondary POF group. Eleven patients (39.3%) had antithyroglobulin antibody, 4 (14.3%) had antimicrosomal antibody, 2 (7.1%) had antinuclear antibody, 2 (7.1%) had rheumatic factor, 1 (3.6%) had anti-smooth muscle antibody, 1 (3.6%) had anti-acetylcholine receptor antibody. Conclusions: Premature ovarian failure may occur as a component of an autoimmune polyglandular syndrome, so patients should be measured with free thyroxine, thyroid-stimulating hormone, fasting glucose and electrolytes. Measurement of thyroid autoantibodies in POF patients may be important in identifying patients at risk of developing overt hypothyoidism, but other autoantibodies may not be suitable for screening test.

Plate Separation (에폭시 접착강판으로 보강된 철근콘크리트 보의 강판단부의 거동특성)

  • 신영수;최완철;홍기섭;홍영균
    • Proceedings of the Korea Concrete Institute Conference
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    • 1994.10a
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    • pp.374-379
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    • 1994
  • This paper deals with the problem of plate separation and anchorage at the ends of steel plates strengthened by EBSP. Test results show that the reinforced concrete beams strengthened by EBSP occurs the premature failure without the beams achieving their full flexural strength at the end of plates. The premature failure is the cause of stress concentrations in the adhesive layer of plate, reinforced concrete incase of lack of plate length. Then a simple, approximate procedure for predicting the shear and normal stress concentrations is investigated by Robert's the ory based on partial interaction theory. The theoretical results are compared, and show close agreement with test results. A method is derived for determining the plate length that prevents the premature anchorage zone failure

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Cyclic and static behaviors of CFT modular bridge pier with enhanced bracings

  • Kim, Dongwook;Jeon, Chiho;Shim, Changsu
    • Steel and Composite Structures
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    • v.20 no.6
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    • pp.1221-1236
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    • 2016
  • Modular structures consist of standardized modules and their connections. A modular bridge pier is proposed to accelerate bridge construction. Multiple concrete-filled steel tubes (CFTs) using commercial steel tubes were chosen as the main members. Buckling restrained bracings and enhanced connection details were designed to prevent premature low-cycle fatigue failure upon cyclic loading. The pier had a height of 7.95 m, widths of 2.5 m and 2.0 m along the strong and weak axis, respectively. Cyclic tests were performed on the modular pier to investigate structural performance. Test results showed that four CFT columns reached yielding without a premature failure of the bracing connections. The ultimate capacity of the modular pier was reasonably estimated based on the plastic-hinge-analysis concept. The modular CFT pier with enhanced bracing showed improved displacement ductility without premature failure at the welding joints.

Theoretical Analysis of Interface Debonding on the Strengthened RC Bridge Decks (성능향상된 RC 바닥판의 계면파괴 해석)

  • 오홍섭;심종성
    • Journal of the Korea Concrete Institute
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    • v.14 no.5
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    • pp.668-676
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    • 2002
  • Especially, when orthotropic material such as uni-dierectionally woven Carbon Fiber Sheet, resisting only the unidirectional tension, is used to strengthening bridge deck, the direction and width of the strengthening material should be considered very carefully. Thus, analysis of the failure characteristics and the premature failure mechanism of the strengthened decks based on the test results are required. In this study, the premature failure due to the interface debonding of strengthening material of the strengthened deck slab are inquired into failure mechanism through both experiments results and analyses with prototype strengthened deck specimens using carbon fiber sheet. From the test results, interface debonding of strengthening material is occured at the crack face

A Review of the Domestic Study Trends on Premature Ovarian Failure Treated with Korean Medicine (조기난소부전의 한의학적 치료에 대한 국내 연구 동향 고찰)

  • Kim, Min-Kyung;Kim, Suna;Kim, Su-Jin;Jeong, Wu-Jin;Huh, Hyo-Seung;Kim, Hye-Gyeong
    • The Journal of Korean Obstetrics and Gynecology
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    • v.33 no.3
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    • pp.20-39
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    • 2020
  • Objectives: This study was performed to examine the domestic study trends on premature ovarian failure (POF) treated with Korean medicine. Methods: We investigated the studies on Korean medicine treatment for premature ovarian failure via searching 4 online databases. Results: 13 clinical studies were selected. All studies were the noncomparative studies, and mainly case reports. Studies were publicated from 2001 to 2019 and the number of studies with 1 subject was the greatest (76.9%). In accompanying symptoms, there was a study which did not report entire cases. In the 11 case reports (13 subjects), the most accompanying symptoms was hot flush (69.2%). In treatment of premature ovarian failure, the most used treatment was herbal medicine, which was used in all studies. Acupuncture treatment was used in 6 studies (46.2%) and moxibustion treatment was used in 8 studies (61.5%). The most common acupuncture point was 內關 (SP6) in acupuncture treatment, and was 關元 (CV4) in moxibustion treatment. The duration of treatment was between 1 month and 20 months, the average 7.76 months. Used outcome measurements were hormone test (84.6%), menstruation (76.9%), Visual analog sclale (VAS) (15.4%), ultrasonography (15.4%), Numeral rating scale (NRS), Body basal temperature (BBT) and Kupperman index (7.7%). In total 70 subjects, 13 subjects (18.6%) became pregnancy and 25 subjects (35.7%) had no effect. Follow up was reported in 6 studies, and the average duration of follow up was 141.63 days. Conclusions: Further clinical trials are needed to establish the evidence for Korean Medicine treatment for premature ovarian failure.

Pattern of Ovulation in Korean Women with Premature Ovarian Failure (한국인 조기난소부전 여성의 배란양상)

  • Kim, Hye-Min;Kim, Jae-Ryoung;Choi, Eun-Joo;Park, Eun-Joo;Hong, Seo-Yu;Lee, Jin-Yong;Park, Won-Il
    • Clinical and Experimental Reproductive Medicine
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    • v.35 no.3
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    • pp.231-238
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    • 2008
  • Objective: Significant portion of premature ovarian failure patients ovulate intermittently and even can achieve pregnancy. The clinical features and reproductive potentials of Korean women with premature ovarian failure have never been elucidated. The purpose of this study is to assess ovarian follicular growth and ovulatory potential. Methods: Complete medical records of fifteen women with idiopathic premature ovarian failure were reviewed retrospectively. Subjects with more than 6 ultrasonographic scans and 36 months of follow-up period were included. Once the ovarian follicle was found by ultrasonography, the follicular growth was serially monitored. The result of ovulation induction of 6 cycles in 4 patients were also evaluated. Rate of positive ovarian follicle by ultrasound, rate of natural follicular growth and response of ovulation induction were assessed. Results: Among the 15 patients, 6 women (40%) had ovarian follicle in random ultrasonography. But the chance of positive follicle per ultrasonography scan was 7% (8 out of 115 scans). One out of 6 women eventually ovulated during the follow-up scan. In remaining 5 subjects, size of follicles remained unchanged. None of 6 ovulation induction cycles resulted successful ovulation. Conclusion: Incidence of positive ovarian follicle in Korean premature ovarian failure patients is lower than that of Western counterpart. This result, however, could not be directly compared because of the differences of study design. The ovulation rate by medical ovulation induction in this group is 0%, which is worse than the reported success rate of Western studies.

Theoretical Study on Interfacial Stresses at RC Beam Repair-Purpose Overlayed by Latex Modified Concrete (LMC로 덧씌우기 보수된 RC보의 계면응력에 관한 연구)

  • Kim, Hyun-Oh;Kim, Seong-Hwan;Kim, Dong-Ho;Lee, Bong-Hak
    • Journal of Industrial Technology
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    • v.24 no.A
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    • pp.179-184
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    • 2004
  • Each year, new technological advancements for repair-purpose are being introduced to overlay the old deterioration of RC bridge deck at highway by latex-modified concrete. The days may come when this old problem will be successfully resolved. While the experimental works and researches are very active at both laboratory and field, only a few theoretical studies were performed on interfacial problems, especially on stress distribution and concentration of RC beam overlayed by latex-modified concrete. The repaired and strengthened structures would induce a premature failure due to the stress concentration at the adhesive layer of different material before the design expected failure. This paper investigated and proposed an analytical model for predicting interfacial shear and normal stresses of RC beam repair-purpose overlayed by latex-modified concrete. This would be used for predicting interfacial stresses and preventing premature failure at interfaces. This study modified Smith-Teng method for applying to cementitious repairing material, which was based on a direct governing equation and linear-elastic approach for interfacial normal and shear stresses. The proposed theoretical model was verified using commercial FEA program, LUSAS, in terms of interfacial stresses predicted by the proposed model and calculated by LUSAS.

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Experimental investigation on optimal shear strengthening of RC beams using NSM GFRP bars

  • Ramezanpour, M.;Morshed, R.;Eslami, A.
    • Structural Engineering and Mechanics
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    • v.67 no.1
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    • pp.45-52
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    • 2018
  • Several techniques have been developed for shear strengthening of reinforced concrete (RC) members by using fiber reinforced polymer (FRP) composites. However, debonding of FRP retrofits from concrete substrate still deemed as a challenging concern in their application which needs to be scrutinized in details. As a result, this paper reports on the results of an experimental investigation on shear strengthening of RC beams using near surface mounted (NSM) FRP reinforcing bars. The main objective of the experimentation was increasing the efficiency of shear retrofits by precluding/postponing the premature debonding failure. The experimental program was comprised of six shear deficient RC beams. The test parameters include the FRP rebar spacing, inclination angle, and groove shape. Also, an innovative modification was introduced to the conventional NSM technique and its efficiency was evaluated by experimental observation and measurement. The results testified the efficiency of glass FRP (GFRP) rebars in increasing the shear strength of the test specimens retrofitted using conventional NSM technique. However, debonding of FRP bars impeded exploiting all retrofitting advantages and induced a premature shear failure. On the contrary, application of the proposed modified NSM (MNSM) technique was not only capable of preventing the premature debonding of FRP bars, but also could replace the failure mode of specimen from the brittle shear to a ductile flexural failure which is more desirable.

An analytical Study on the premature Failure Behavior of RC Beams Strengthened by Steel Plates (강판으로 보강된 RC 보의 조기파괴거동 해석)

  • 심종성;김규선
    • Proceedings of the Korea Concrete Institute Conference
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    • 1998.10b
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    • pp.821-826
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    • 1998
  • The design methods for the steel plate strengthened RC structures are not well established yet because the structural behavior of plated RC beams is more complex than that of regular unplated ones. The main purpose of this paper is to present the premature failure mechanism of steel plate strengthened RC beams. The analytical models of interfacial stress and normal are also proposed in this paper. The comparisons between the analytical results using the proposed theory and experimental ones relatively satisfied.

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