• Journal of Microbiology and Biotechnology
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• v.28 no.5
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• pp.796-808
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• 2018

The intracellular bacterium Wolbachia pipientis is widespread in arthropods. Recently, possibilities of novel Wolbachia-mediated hosts, their distribution, and natural rate have been anticipated, and the coconut leaf beetle Brontispa longissima (Gestro) (Coleoptera: Chrysomelidae), which has garnered attention as a serious pest of palms, was subjected to this interrogation. By adopting Wolbachia surface protein (wsp) and multilocus sequence type (MLST) genotypic systems, we determined the Wolbachia infection density within host developmental stages, body parts, and tissues, and the results revealed that all the tested samples of B. longissima were infected with the same Wolbachia strain (wLog), suggesting complete vertical transmission. The MLST profile elucidated two new alleles (ftsZ-234 and coxA-266) that define a new sequence type (ST-483), which indicates the particular genotypic association of B. longissima and Wolbachia. The quantitative real-time PCR analysis revealed a higher infection density in the eggs and adult stage, followed by the abdomen and reproductive tissues, respectively. However, no significant differences were observed in the infection density between sexes. Moreover, the wsp and concatenated MLST alignment analysis of this study with other known Wolbachia-mediated arthropods revealed similar clustering with distinct monophyletic supergroup B. This is the first comprehensive report on the prevalence, infection dynamics, and phylogeny of the Wolbachia endosymbiont in B. longissima, which demonstrated that Wolbachia is ubiquitous across all developmental stages and distributed in the entire body of B. longissima. Understanding the Wolbachia infection dynamics would provide useful insight to build a framework for future investigations, understand its impacts on host physiology, and exploit it as a potential biocontrol agent.

• Journal of Korean Neurosurgical Society
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• v.63 no.6
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• pp.767-776
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• 2020

Objective : The aim of this study is to evaluate the feasibility of posterior cervical foraminotomy (PCF) for adjacent segmental disease (ASD) after anterior cervical fusion (ACF). As ACF is accepted as the standard treatment for cervical spondylosis, many studies have been conducted to evaluate the efficacy of various surgical techniques to overcome symptomatic ASD after the previous surgery. Herein, PCF was performed for the treatment of symptomatic ASD and the feasibility of the surgery was evaluated. Methods : Forty nine patients who underwent PCF due to symptomatic ASD from August 2008 to November 2017 were identified. For demographic and perioperative data, the sex, age, types of previous surgery, ASD levels, operation times, and bleeding amount were recorded. The clinical outcome was assessed using the visual analogue scale for the neck and arm, the modified Odom's criteria as well as neck disability index. Radiologic evaluations were performed by measuring disc softness, disc height, the cervical 2-7 sagittal vertical axis, cervical cobb angle, and facet violation. Results : Thirty-seven patients were enrolled in this study. The patients were divided into two groups based on the location of the pathology; paracentral (group P) or foramina (group F). Both groups showed significant clinical improvement (p<0.05). The proportion of calcified disc and facet violations was significantly larger in group F (p<0.05). The minimal disc height decrease with mild improvement on sagittal alignment and cervical lordosis was radiologically measured without statistical significance in both groups (p>0.05). Conclusion : PCF showed satisfactory clinical and radiologic outcomes for both paracentral and foraminal pathologies of ASD after ACF. Complications related to anterior revision were also avoided. PCF can be considered a feasible and safe surgical option for ASD after ACF.

• Korean Chemical Engineering Research
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• v.47 no.1
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• pp.1-10
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• 2009

As a demand for the portable device requiring smaller size and better performance is in hike, reducing the size of conventionally used planar 2 dimensional chip cannot be a solution for the enhancement of the semiconductor chip technology due to an increase in RC delay among interconnects. To address this problem, a new technology - "3 dimensional (3D) IC chip stack" - has been emerging. For the integration of the technology, several new key unit processes (e.g., silicon through via, wafer thinning and wafer alignment and bonding) should be developed and much effort is being made to achieve the goal. As a result of such efforts, 4 and 8 chip-stacked DRAM and NAND structures and a system stacking CPU and memory chips vertically were successfully developed. In this article, basic theory, configurations and key unit processes for the 3D IC chip integration, and a current tendency of the technology are explained. Future opportunities and directions are also discussed.

• International Journal of Highway Engineering
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• v.15 no.4
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• pp.95-105
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• 2013

PURPOSES: The purpose of this study is to research the influence of road traffic noise by road slope through the analysis of the field road traffic noise and determine consideration of road slope in the case of appling active noise cancellation. METHODS: This study measures vehicle's noise by the NCPX method at the three field sections such as uphill, downhill, and flatland. Total sound pressure and sound pressure level by the 1/3 octave band frequency are calculated through the raw field data. Total sound pressure level is compared by ANOVA test and T test statistically. The results obtained are compared in accordance with the road slope and the progress of the uphill section. RESULTS : The noise characteristic of early, medium, and last parts of uphill was found to be consistent when the vehicle was travelling uphill section. The result of statistical test, it was shown that total sound pressures are not different each other. According to the comparison by the geometry, sound pressure of the uphill section was higher than those of the flatland and downhill section in high frequency band. By the result of statistical test, total sound pressure are different according to geometry in the case of high vehicle speed. In the comparison result by road slope, each sound pressure level was found to be consistent in total frequency. However, total sound pressure proportionally increased according to road slope. CONCLUSIONS: It is found that the effect of road slope on noise generation was little in this experimental sites.

• Journal of the Korean Society for Nondestructive Testing
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• v.34 no.1
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• pp.23-30
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• 2014

The wear characteristics of $SiC_f$/SiC composites were evaluated according to the alignment direction of the fibers, and the elastic wave-generated friction was detected and analyzed in wearing. The friction coefficient and wear loss were similar in the longitudinal and the transverse direction of the fibers. However, these values were lower in the vertical direction of the fibers because of the brittle nature of the fiber. The friction coefficient and the wear loss were directly proportional to each other. The dominant frequencies were 58.6 kHz for monolithic SiC and 117.2 and 136.7 kHz for $SiC_f$/SiC composites, respectively.

• Journal of the Optical Society of Korea
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• v.13 no.4
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• pp.428-433
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• 2009

A photonic crystal fiber with two large air holes outside the holey cladding region is fabricated to induce an effective long periodic grating (LPG) in the core by an electric arc discharge. We believe that the two large air holes lead to the asymmetric perturbation in the core under the electric arc discharge, thereby introducing the coupling to the first higher-order mode. The transmission characteristics of the PCF with the LPG for the external perturbation such as strain, curvature, and temperature are also investigated. It was found that the shift of resonance peak in the transmission spectrum depends on the bending direction. The curvature of 8.55 $m^{-1}$ results in the center wavelength shifts of 1.8, 4.3, and 11 nm for a vertical, diagonal, and horizontal direction of the curvature to the large air-hole alignment, respectively.

• International journal of advanced smart convergence
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• v.7 no.1
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• pp.33-41
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• 2018

This study was designed to provide basic data for developing exercise program that helps correcting posture by knowing the effect of strengthening and elongation exercises of upper extremity muscle to forward head posture correction. In this study determined subjects whether they had forward head posture or not. On the basis of the New York state posture rating, if a subject's posture is match up with the normal standard posture, gives 5 points and if the posture is slightly get out of the normal standard posture, gives 3 points and if the posture is apparently get out of the standard, gives 1 points. When determining the forward head posture, if talus, humerus and outer ear center are on the same line, it is determined as normal and if outer ear center is off the line less than 1.0cm, it is a slight deformation and if outer ear center is off the line more than 1.0cm, it is a high deformation. In the study selected people who have more than 1 cm gap between two vertical lines start from outer ear center and acromion separately as subjects. Length between the ideal alignment line measured by using goniometer and temporal region showed statistically significant decrease as $2.36{\pm}1.07cm$ before the intervention and $1.06{\pm}0.88cm$ after the intervention. After 4 weeks of neck and chest extensor muscle exercise, the group who exercised both showed increase in range of neck joint motion and neck flexion of the forward head posture. Meanwhile the group who only exercised neck extensor muscle only and the group who only exercised chest extensor muscle didn't showed statistically significant result. That only the group who exercised both muscles showed significant result is the different with studies before. Because this study didn't target patient who had a lesion, couldn't compare effect of the conservative manner and exercise. However, this study provides the fact that the group who exercised both neck and chest muscle had more effect than the control group.

• Journal of the Microelectronics and Packaging Society
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• v.9 no.4
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• pp.55-60
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• 2002

This paper presents a technique for the preparation of vertically grown CNTs by ICPHFCVD(inductively coupled plasma hot filament chemical vapor deposition) below $580^{\circ}C$. Purification of the CNTs(carbon nanotubes) using RE(radio frequency) plasma in a one step process, based on the different etching property of the Ni-tip, amorphous carbon and carbonaceous materials is also discussed. After purifying the grown materials. CNTs shown the multi walled and hollow typed structure. The typical outer and inner diameters or CNT were 50 nm and 25 nm, respectively. The graphitic wall was composed of 82 layers and the distance between wall and wall was 0.34 nm. From the results of TEM observation, the Ni catalyst at the tip of the carbon nanotubes were effectively removed by using a RF plasma etching, continuously.

• Journal of Biomedical Engineering Research
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• v.29 no.1
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• pp.52-58
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• 2008

The object of this study is to investigate the effects of intermittent cyclic stretching on the smooth muscle cells (SMCs) seeded onto aligned multi-layered fibrous scaffold. To make multi-layered fibrous scaffold, polyurethane (PU) and poly(ethylene oxide) (PEO) were electrospun alternatively, then were immersed into distilled water to extract PEO. Various types of scaffolds were fabricated depending on fiber directions, i.e., aligned or randomly oriented. The direction of stretching was either parallel or vertical to the fiber direction for the aligned scaffolds. The stretching was also applied to the randomly aligned scaffolds. The duration of stretching was 2 min with 15 min resting period. During the stretching, the maximum and minimum strain was adjusted to be 10 and 7%, respectively with the frequency of 1 Hz. The bioactivities of cells on the scaffolds were assessed by quantifying DNA, collagen, and glycosaminoglycan (GAG) levels. And the cell morphology was observed by staining F-actin. SMCs under parallel stretching to the fiber direction responded more positively than those in other conditions. From the results, we could explain the morphological effect of a substrate on cellular activities. In addition the synergistic effects of substrate and mechanical stimuli effects were confirmed.

• Journal of Korean Medical Science
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• v.33 no.48
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• pp.316.1-316.10
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• 2018

Background: Water pressure and muscle contraction may influence bone mineral density (BMD) in a positive way. However, divers experience weightlessness, which has a negative effect on BMD. The present study investigated BMD difference in normal controls and woman free-divers with vertebral fracture and with no fracture. Methods: Between January 2010 and December 2014, traditional woman divers (known as Haenyeo in Korean), and non-diving women were investigated. The study population was divided into osteoporotic vertebral fracture and non-fracture groups. The BMD of the lumbar spine and femoral neck was measured. The radiological parameters for global spinal sagittal balance were measured. Results: Thirty free-diving women and thirty-three non-diving women were enrolled in this study. The mean age of the divers was $72.1{\pm}4.7$ years and that of the controls was $72.7{\pm}4.0$ years (P = 0.61). There was no statistical difference in BMD between the divers and controls. In divers, cervical lordosis and pelvic tilt were significantly increased in the fracture subgroup compared to the non-fracture subgroup (P = 0.028 and P = 0.008, respectively). Sagittal vertical axis was statistically significantly correlated with cervical lordosis (Spearman's rho R = 0.41, P = 0.03), and pelvic tilt (Spearman's rho R = 0.46, P = 0.01) in divers. Conclusion: BMD did not differ significantly between divers and controls during their postmenopausal period. When osteoporotic spinal fractures develop, compensation mechanisms, such as increased cervical lordosis and pelvic tilt, was more evident in traditional woman divers. This may be due to the superior back muscle strength and spinal mobility of this group of women.