• The Journal of Korean Obstetrics and Gynecology
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• v.37 no.1
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• pp.60-74
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• 2024

Objectives: This review aimed at investigating the research trends of animal experiment on the acupuncture for premature ovarian failure (POF). Methods: Studies were searched from PubMed, Cochrane Library, EMBASE, CINK, KISS, RISS, OASIS, KMBASE up to November 2023. Terms as POF, acupuncture, electroacupuncture were used. Results: Of 189 screened, 13 studies are selected and analyzed. The combined results showed that treatment group was effective of improving serum sex hormones level, ovarian morphology, expression related mRNA and protein compared with control group. The most frequently used acupoints were SP6, CV4. Conclusions: Included studies showed that acupuncture might have effect on POF. Further research should be conducted to verify its therapeutic mechanisms and effectiveness.

• Journal of Chest Surgery
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• v.32 no.8
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• pp.702-708
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• 1999

Background: Surgical closure of the PDA in premature infants with complications or contraindications to indomethacin use, or recurrence of symptomatic PDA is a safe and effective procedure with low operative risk and minimal complications. Material and Method: From April 1996 to August 1998, 11 premature infants with body weight under 1.5 kg at operation underwent operation for a symptomatic PDA (male:5, female: 6). Associated dise ases were congenital heart disease(7), hyaline membrane disease(6), intraventricular hemor rhage(4), pneumonia(4), pneumothorax(3), hyperbilirubinemia(2), necrotizing enterocolitis(2), renal failure(1), epilepsy(1), and hydrocephalus(1). Surgical techniques are hemoclipping(8) and ligation(3). The size of PDA was 3~6 mm (5.0$\pm$1.2). Result: Systolic and diastolic blood pressure rised and heart rates decreased after PDA closure. ABGA improved postoperatively. There were no surgical complications. Six infants with improved ABGA data were weaned from mechanical ventilatory support. The follow-up durations after discharge were 3 month to 12 month. Five deaths were not related to operation. The causes of death were hyaline membrane disease(2), bronchopulmonary dysplasia with pneumonia(1), sepsis(1), and con gestive heart failure with respiratory distress syndrome(1). Conclusion: Early operative closure is the treatment of choice in most premature infants with a hemodynamically significant shunt(PDA), recurrence of symptomatic PDA, complications of Indomethacin, or contraindi cations to Indomethacin.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.16 no.6
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• pp.181-186
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• 2007

UBM (Under Bump Metallurgy) of flip chip assemblies consists of several layers such as the solder wetting, the diffusion barrier, and the adhesion layers. In addition, IMC layers are formed between the solder wetting layers (e.g. Cu, Ni) and the solder. The primary failure mechanism of the solder joints in flip chips is widely known as the fatigue failure caused by thermal fatigues or electromigration damages. Sometimes, the premature brittle failure occurs in the IMC layers. However, these phenomena have thus far been viewed from only experimental investigations. In this sense, this paper presents a method for solid modeling of IMC layers in flip chip assemblies, thus providing a pre-processing tool for finite element analysis to simulate the IMC failure mechanism. The proposed modeling method is CSG-based and can also be applied to the modeling of UBM structure in flip chip assemblies. This is done by performing Boolean operations according to the actual sequences of fabrication processes

• Structural Engineering and Mechanics
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• v.77 no.2
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• pp.273-291
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• 2021

The strut-and-tie method (STM) has been widely accepted and used as a rational approach for the design of disturbed regions ('D' regions) of reinforced concrete members such as in corbels and deep beams, where traditional flexure theory does not apply. This paper evaluates the applicability of the equilibrium based STM in strength predictions of deep beams (with rectangular and circular cross-section) and corbels using the available experiments in literature. STM is found to give fairly good results for corbel and deep beams. The failure modes of these deep members are also studied, and an optimum amount of distribution reinforcement is suggested to eliminate the premature diagonal splitting failure. A comparison with existing empirical and semi empirical methods also show that STM gives more reliable results. The nonlinear finite element analysis (NLFEA) of 50 deep beams and 20 corbels could capture the complete behaviour of deep members including crack pattern, failure load and failure load accurately.

• Neonatal Medicine
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• v.28 no.1
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• pp.1-6
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• 2021

Persistent pulmonary hypertension of the newborn (PPHN) is a consequence of the failure of a decrease in the elevated pulmonary vascular resistance after birth. Pulmonary vasodilators, including inhaled nitric oxide (iNO), have been the mainstream of targeted therapy for PPHN, but no drugs have been proven to be effective in preterm infants with PPHN. The fetus remains hemodynamically stable despite lower arterial oxygen tension and pulmonary blood flow as compared to full-term newborns. This adaptation is due to the lower oxygen requirement and high oxygen-carrying capacity of fetal circulation. The immature lungs of preterm infants are more vulnerable to reactive oxygen species, and the response of pulmonary vascular dilatation to blood oxygen tension is blunted in preterm infants. Recently, iNO has been reported to be effective in a selected group of preterm infants, such as those with prolonged preterm rupture of membrane-oligohydramnios-pulmonary hypoplasia sequence. PPHN in preterm infants, along with maximum supportive treatment based on fetal physiology and meticulous assessment of cardiovascular function, is in dire need of new treatment guidelines, including optimal dosing strategies for pulmonary vasodilators.

• Journal of Applied Reliability
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• v.16 no.2
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• pp.104-109
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• 2016

Purpose: The purpose of this study is to analyze fracture behavior and failure mechanism of porous titanium for dental implant fabricated by space holder process. Method: Three porous titanium specimens with a specific volume fraction of open pore were test by 3 point bending and compression stress condition, respectively. Fracture appearance was observed by scanning electron microscope and discussed in relation with oxygen content. Results: For compression-tested specimens, two specimen showed brittle failure, while the other one showed normal failure after deformation. High oxygen content was detected in the brittle-fractured specimen. Several micro-cracks initiated at the struts propagated down to the bottom of the specimen resulting in normal failure. Conclusion: Oxygen contamination during the fabrication process can leads brittle premature failure, and hence quality problem of the porous titanium for dental implant.

• Journal of the Korea Concrete Institute
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• v.22 no.4
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• pp.461-472
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• 2010

This paper investigates the behavior of precast concrete (PC) shear walls with a new vertical connections for a fast remodeling construction. The C-type vertical connections for the PC wall systems are proposed for transfer of bending moment between top and bottom walls in the vertical direction while a shear key in the center of wall is prepared to transfer shear forces by bearing action. The proposed vertical connections allows easy fabrication thanks to slots at the edges of wall in opposite directions. The plane PC wall systems subject to lateral load are compared with ordinary wall systems by investigating the effects of connection on the stiffness, strength, ductility, and failure modes of whole systems. The load-displacement relationship and influence of premature failure of connections are examined. The experimental test showed that the longitudinal reinforcing steel bars placed at the edges of walls yielded first and the ultimate deformation were terminated due to premature failure of connections. The diagonal reinforcements for efficient shear transfer in the walls were not effective. The strength and deformation obtained through the section analysis were generally in agreement with the experimental data, and indicated that. Gap opening contributed to the deformation behavior more than any other factors.

• Childhood Kidney Diseases
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• v.9 no.2
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• pp.255-262
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• 2005

Battler and Bartter-like syndromes, which include classic Bartter syndrome(type III), neonatat Bartter syndrome(type I, II or IV) and Gitelman syndrome, are autosomal - recessively inherited renal tubular disorders characterized b)r hypokalemic metabolic alkalosis, salt wasting and normal to low blood pressure. Neonatal Bartter syndrome is characterized by intrauterine polyhydramnios, premature delivery, life-threatening episodes of fever and dehydration, subsequent failure to thrive, and severe hypercalciuria with nephrocalcinosis and osteopenia. It is caused by mutations in NKCC2(type I), ROMK(type II) or BSND(type IV) genes. If diagnosed and treated early, the progression to renal failure can be prevented and catch-up growth and normal development are achieved. We report here a 6 month-old infant with neonatal Bartter syndrome who presented with hypokalemic metabolic alkalosis, polyhydramnios and premature delivery, persistent high fever and dehydration, failure to thrive, hypercalciuria, and nephrocalcinosis. He received indomethacin and potassium chloride per os and show ed catch-up growth and normal developmental profile at 19 months of age. (J Korean Soc Pediatr Nephrol 2005;9:255-262)

• Journal of the Korea Concrete Institute
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• v.13 no.3
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• pp.221-227
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• 2001

Both strength and stiffness of RC structures strengthened by a steel plate greatly increase and however, their ductility might not be sufficient because premature failures usually occur at the adhesive-concrete interface. In this study, Mohr-Coulomb criterion was adopted to examine the bonding failure mechanism, and the diagonal shear bonding test, the direct shear bonding test, and the flexural test on RC beams strengthened by a steel plate were carried out to measure the bonding properties. It is found from the experimental and numerical results that the cohesive strengths of epoxy-concrete interfaces are ranging from 50 kgf/㎠ to 70 kgf/㎠ when the friction angle is 45°. Bonding failure loads can be predicted by applying the bonding properties to the structural analysis of RC beams strengthened by steel plate. By considering them in the design of strengthened beams, the premature failure would be effectively prevented.

• Transactions of the Korean Society of Mechanical Engineers
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• v.19 no.2
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• pp.382-390
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• 1995

Failure of connecting rod in automotive engine may cause catastrophic situation. The corner radius at small end has an effect on stress raising. To investigate the stress distribution in connecting rod during operation, the finite element analysis was used by giving possible maximum tension and compression. Excessive sizing after forging connecting rod may result in the tensile residual stress which lower the fatigue life and cause premature failures. It was shown that when the sizing amount is too large, the location of high tensile residual stress coincide with that of high stress amplitude during operation through the elastic-plastic finite element analysis. The endurance limit moves down due to the surface finish and decarburization, which combines with the movement of resultant stress points to dangerous range. It was concluded that the precise control of sizing and enough corner radius are necessary to a reliability of connecting rod.