• Journal of the Korean Society of Radiology
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• v.17 no.6
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• pp.903-909
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• 2023

The purpose of this study is to compare and analyze the effect of changes in the patient's central position on the exposure dose and image quality of surrounding organs during a chest lateral examination using an Auto Exposure Control(AEC). The experiment was conducted on a human body phantom. A needle was attached to the lower part of the center of the coronal plane of the phantom, and a lead ruler was attached to the lower part of the detector so that the 50 cm point was located at the lower center of the AEC ion chamber. The exposure conditions were 125 kVp, 320 mA, the distance between the source and the image receptor was 180 cm, and the exposure field size was 14 × 17 inches. Only one AEC ion chamber was used at the bottom center, and the density was set to '0' and sensitivity to 'Middle', and the central X-ray was incident vertically toward the 6th thoracic vertebra. With AEC mode applied, the 50 cm point of the needle and lead ruler were aligned and the phantom was moved 5 cm toward the stomach (F5) and 5 cm toward the back (B5), and the dose factor was analyzed by measuring ESD. The ESD of the thyroid gland according to the change in patient center position was 232.60±2.20 μGy for Center, 231.22±1.53 μGy for F5, and 184.37±1.19 μGy for B5, and the ESD of the breast was 288.54±3.03 μGy for Center, F5 was 260.97±1.93 μGy, B5 was 229.80±1.62 μGy, and the ESD of the center of the lung was 337.02±3.25 μGy for Center, F5 was 336.09±2.29 μGy, and B5 was 261.76±1.68 μGy. As a result of comparing the average values of dose factors between each group, the difference in average values was statistically significant (p<0.01), and each group appeared to be independent. As a result of the study, there was no significant difference in the dose to the thyroid, breast, and center of the lung according to the change in the patient's central position, except for the breast (10%) when the patient moved forward about 5 cm. However, movement of about 5 cm posteriorly resulted in an average dose reduction of 23.7%. Additionally, when the patient's central position was moved to the rear, image quality deteriorated.

• Quality Improvement in Health Care
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• v.10 no.2
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• pp.190-203
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• 2003

Background: Dental hygienists are at risk of acquiring infections through exposure to infectious agents. This study explores the frequency of exposure to infectious agents and infection control practices among dental hygienists. Methods: We undertook a cross-sectional survey to examine the exposure to infectious agents and infection control practices among dental hygienists through questionnaire. Data were obtained from 124 dental hygienists attending educational conferences. A multiple logistic regression analysis was conducted to determine the factors that effect infection control practices in relation to age, completion of infection control education, recognition of their own serum hepatitis Ag/Ab status, the number of one day patients, location of clinics, type of clinics, and career years. Result: Of the 124 dental hygienists, 91.7% were exposed to at least one accident such as needle stick injuries during their practices periods. The health screening coverage rate in dental hygienists was 16.5%. The number of one day patients and career years were important in relation to infection control practices among dental hygienists. The adjusted odds ratio estimates for career years were 5.049 times greater(95% Cl 1.238-20.597) for groups with over 4 career years than under 2 career years. That for the number of one day patients were 0.261(95% Cl 0.071-0.955) lower for through 20 up to 30 patients, 0.531(95% Cl 0.102-2.78) lower for through 30 up to 40 patients and 0.498(95% Cl 0.123-2.017) lower for more than 40 patients than under 20 patients. Conclusion: From these results, prevalence of infection control practices among dental hygienists is related to the number of one day patients and career years. Prevention of cross infection and reduction of future transmission should be a priority to dental hygienists for promotion of infection control and further efforts to educate newcomers on infection prevention should be made.

• Korean Journal of Clinical Laboratory Science
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• v.37 no.3
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• pp.178-184
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• 2005

Carry over contamination has been reduced in some systems by flushing the internal and external surfaces of the sample probe with copious amount of diluent. It between specimens should be kept as small as possible. A built-in, continuous-flow wash reservoir, which allows the simultaneous washing of the interior and exterior of the syringe needles, addresses this issue. In addition, residual contamination can further be prevented through the use of efficient needle rinsing procedures. In discrete systems with disposable reaction vessels and measuring cuvets, any carry over is entirely caused by the pipetting system. In analyzers with reuseable cuvets or flow cells, carry over may arise at every point through which high samples pass sequentially. Therefore, disposable sample probe tips can eliminate both the contamination of one sample by another inside the probe and the carry over of in specimen into the specimen in the cup. The results of the applicative carry over experiment studied on 21 items for total protein (TP), albumin (ALB), total bilirubin (TB), alkaline phosphatase (ALP), aspratate aminotranferase (AST), alanine aminotranferase (ALT), gamma glutamyl transferase (GGT), creatinine kinase (CK), lactic dehydrogenase (LD), creatnine (CRE), blood urea nitrogen (BUN), uric acid (UA), total cholesterol (TC), triglyceride (TG), glucose (GLU), amylase (AMY), calcium (CA), inorganic phosphorus (IP), sodium (Na), potassium (K), chloride (CL) tests in chematology were as follows. Evaluation of process performance less than 1% in all tests was very good, but a percentage of ALB, TP, TB, ALP, CRE, UA, TC, GLU, AMY, IP, K, Na, and CL was 0%, implying no carry over. Other tests were ALT(-0.08%), GGT(-0.09%), CK(0.08%), LD(0.06%), BUN(0.12%), TG (-0.06%), and CA(0.89%).

• Journal of Korean Medicine Rehabilitation
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• v.31 no.4
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• pp.49-63
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• 2021

Objectives This study aimed to investigate the trend in treating fracture with acupuncture and to evaluate the quality of case reports. Methods All case reports of fractures treated with acupuncture were extracted from four Korean web databases. We classified these studies by five fracture sites and investigated frequently used meridian and acupoint, outcome measurements, treatment period. And we assessed the quality of the case reports by the STandards for Reporting Interventions in Clinical Trials of Acupuncture (STRICTA) guidelines. Results A total of 33 case reports were included. The outcome measurements were divided into six categories, and the outcome measurements used in more than three studies showed improvement in patient symptoms. The mainly used meridians for each fracture site were as follows: chest and abdomen (GB, LR, CV), back (BL, GB), upper limb (LI, TE), lower Limb (GB, ST, BL, SP). The most commonly used acupoints for each fracture site were as follows: chest and abdomen (Ashi points, GB24, GB25, GB26, LR13, LR14, CV16, CV17, CV18, CV19), back (BL23, BL24, BL25, BL26, BL40, BL51, BL52, BL60, GB34), upper limb (LI4, LI10, LI11, TE3), lower limb (GB34, GB40). According to the STRICTA guidelines, more than 54.54% of the reports were found to be 'not reported' or 'not sufficient' in the following categories: 'response sought', 'description of participating acupuncturist', and 'number of needle insertions per subject per session'. Conclusions The meridians and acupuncture points frequently used for acupuncture treatment of fractures were near the fracture site. Future clinical studies involving acupuncture must be reported in accordance with the STRICTA guidelines to improve transparency and uniformity.

• Journal of the Korean Society of Radiology
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• v.17 no.5
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• pp.679-684
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• 2023

Venous puncture is widely used to obtain blood samples for pathological examination. Because the invasive venipuncture method using a needle is repeatedly performed, the pain suffered by the patient increases, so our research team pre-developed a miniaturized near-infrared (NIR) imaging system in advance. To improve the image quality of the acquired NIR images, this study aims to model the non-local means (NLM) algorithm, which is well known to be efficient in noise reduction, and analyze its applicability in the system. The developed NIR imaging system is based on the principle that infrared rays pass through dichroic and long-pass filters and are detected by a CMOS sensor module. The proposed NLM algorithm is modeled based on the principle of replacing the pixel from which noise is to be removed with a value that reflects the distances between surrounding pixels. After acquiring an NIR image with a central wavelength of 850 nm, the NLM algorithm was applied to segment the final vein area through histogram equalization. As a result, the coefficient of variation of the NIR image of the vein using the NLM algorithm was 0.247 on average, which was an excellent result compared to conventional filtering methods. In addition, the dice similarity coefficient value of the NLM algorithm was improved by 62.91 and 9.40%, respectively, compared to the median filter and total variation methods. In conclusion, we demonstrated that the NLM algorithm can acquire accurate segmentation of veins acquired with a NIR imaging system.

• Korean Journal of Ecology and Environment
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• v.49 no.4
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• pp.296-307
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• 2016

Ecological restoration is an eco-technology, which heals the nature damaged by human activity by imitating organization and function of the integrate nature and thereby provide an inhabitable space for diverse organisms. Such an ecological restoration has to be carried out by applying restoration plan prepared based on the results of diagnostic evaluation discussed in the diversified respects. This study aims to prepare an ecological restoration plan of the damaged forest ecosystem in Mt. Moodeung National Park. To arrive at the goal, first of all, we diagnosed quality of forest landscape established in Mt. Moodeung National Park based on natural (topography, climate, and distribution of vegetation) and artificial (land use, linear landscape element) factors. In addition, we evaluated the integrity of each zone divided by linear landscape element quantitatively based on geometric property and land use intensity. As the result of analysis, topography of Mt. Moodeung National Park tended to be depended on weathering property of parent rock and vegetation zones were divided to three vegetation zones. Based on land use pattern, deciduous broad-leaved forest, evergreen needle-leaved forest, and mixed forest occupied about 90% of Mt. Moodeung National Park. Mean score of forest landscape quality was shown in $69.86{\pm}11.41$. As a result, forest landscape elements in Mt. Moodeung National Park were influenced greatly by human activity and the degree was depended on topographic condition. This study suggested the synthetic restoration plan to improve ecological quality of Mt. Moodeung National Park based on the results of diagnostic evaluation.

• Clinical and Experimental Reproductive Medicine
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• v.26 no.2
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• pp.171-178
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• 1999

The follicular fluid (FF) of ovary contains various biological active products which affected on the growth of follicles and the fertilization of oocyte in physiological reproductive process of mammals. This study was designed to determine the effects of human FF on fertilization of oocyte and embryonal development in vitro culture. The FF was prepared as clear without blood contamination by needle aspiration from mature follicles of human at the time of oocytes retrieval for in vitro fertilization (IVF). As the medium for culture in vitro of embryonal cells, human tubal fluid (HTF) supplemented with follicular fluids at concentrations of 10%, 40% and pure FF were used. These effects were compared to control group of cultured embryos in HTF supplemented with 0.4% BSA (bovine serum albumin). For IVF, 64 eggs in control group, 67 eggs in 10% FF, 57 eggs in 40% FF and 64 eggs in pure FF were respectively allocated. And the rates of fertilization were almost similar in all groups as resulting 82.81% in control, 85.07% in 10% FF, 87.71% in 40% FF and 81.25% in pure FF. On the examination for embryonal cleavage from fertilized eggs, the rates of developing to 4 cell stage was similar in all groups, as results 98.11% in control, 98.27% in 10% FF and 98% in 40% FF but 78.84% in pure FF. And the rates of developing to 8-16 cell stage were significantly reduced as 44% in 40% FF and 44.23% in pure FF (p<0.05) compare to 71.69% in control media. As likewise, the rates of developing to morular stage were also significantly reduced to 36% (p<0.05) and 21.15% (p<0.01) respectively in 40% FF and pure FF. And the rates to blastocystic stage of embryo was lowest as 7.69% in pure FF (Table 1). The quality of embryonal cells on cleavage to the 8-16 cell stage was poorer, higher concentrations of FF. The rates of grade 1 in pure FF, as 23.07%, was lowest compare to those of other groups, in which the rates of grade 1 in control, 10% FF and 40% FF were 58.49%, 47.36% and 34% respectively. And on the contrary, the rate of grade 4 in pure FF was highest as 23.07%, while those were 5.66% in control, 8.77% in 10% FF and 20% in 40% FF (Table 2). On the viability of embryos, the rate of embryonal cell death was more rise, at the higher concentrations as well as longer exposure in the follicular fluid. At 48 hours after in vitro culture of embryos, the rate of survival embryos in pure FF was markedly lowered as 44.23%, compare to that of control (p<0.05). But there was not significant difference between the rates of survival embryos in each group beside the pure FF, which the rates were 77.35% in control, 70.17% in 10% FF and 60% in 40% FF respectively. And at 72 hours after in vitro culture, the rates of survival embryos were also significantly dropped to 21.15% in pure and 36% in 40% at concentration of FF compare to 62.26% in control (p<0.05, p<0.01). Finally, the rate of embryonal death at 96 hours after in vitro culture was highest as 82.69% in pure FF among all groups which those were 35.84 in control, 56.14% in 10% FF and 64% in 40% FF respectively (Fig. 1, 2, 3). In conclusion, this study suggests that the FF has no effects, in particular, to the in vitro fertilization of oocytes but exerted a bad effect to the cleavage, quality and viability of the embryonal cells during in vitro culture. However, the FF is harmful on embryonal development at conditions in higher concentration and especially on the embryos after $8{\sim}16$ cell stage.

• Journal of Korean Society of Forest Science
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• v.32 no.1
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• pp.1-8
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• 1976

One of the most common needle leaf species used in planting in Korea is korean pine (Pinus koraiensis S. et Z.), and jack pine (Pinus banksiana Lamb.) is one of the test species for suitability. The relation of nursery bed density of 2-1 korean pine and 1-1 jack pine was studied at the Kwang Nung Nursery, Central Branch Station of Forest Research Institute, and about 40km north of Seoul. Nursery bed density of 2-1 korean pine, which ranged from 36 to 324 trees per square meters and of 1-1 jack pine, which ranged from 25 to 169 trees per square meters, had a marked effect on caliper, height, dry weight and percent and amount of plantable stock. The soil physical and chemical properties is silt plus clay, 50.55 percent; organic matter, 2.09 percent; total nitrogen, 0.13 percent; available phosphorus, 253.25 ppm; exchangeable potash, 0.46 m.e/100g; and pH, 5.58. As the density of the nursery seedling stand of 2-1 korean pine increases, the average tree height increases (Fig. 1A), but in 1-1 jack pine density do not affect to increase or decrease the average tree height. As the density of nursery bed increases, the average stem caliper (at 2cm above ground line) and dry weight decrease (Fig. 1B), but the decreasing rate is more seriously in 1-1 jack pine than 2-1 korean pine (Fig.5). As increasing the density of nursery bed, the T/R ratio of trees of the test species increase. Also the dry weight of leaf, stem and root parts are decreasing in proportion to the increase of stand density, but the drop rate of jack pine is more rapid than korean pine (table. 1) The patent facts of difference of growth characteristics between 2-1 korean pine and 1-1 jack pine were studied. These facts should be used to select the scale of stand density at the nursery bed or the plantable site. Korean pine is demanded high density, on the other hand in jack pine low density are more suitable to manage the stand density. Stands of comparatively low density had the greatest percentage of high-quality stock, and the stands of high density had less than the high quality trees of low density. An important criterion of the best density is percent and number of high-quality trees produced per square meter of bed area. Stem caliper and stem height of seedling is used in most public nurseries to sort seedling into plantable grades. The stock grade standard has set at 4.5mm caliper and 16cm height of 2-1 korean pine as the minimum desired stem caliper and height. By the result studies, the plantable stock grade standards of 2-1 korean pine used at stem height 16cm and stem caliper 4.5mm from public nurseries should be reformed to stem height 18cm and stem caliper 4.0mm by the growth characteristics and the tree distribution of stem height and caliper of relation to density. For the 2-1 korean pine, best density should be about 160 to 200 trees per square meter according to soil fertility. For the 1-1 jack pine, the suitable standard of plantable stock should be at stem height 25cm and caliper 6mm (at 2cm above ground line) and best density was about 100 to 120 trees.

• Korean Journal of Materials Research
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• v.24 no.9
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• pp.443-450
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• 2014

Amorphous (a-Si) films were epitaxially crystallized on a very thin large-grained poly-Si seed layer by a silicide-enhanced rapid thermal annealing (SERTA) process. The poly-Si seed layer contained a small amount of nickel silicide which can enhance crystallization of the upper layer of the a-Si film at lower temperature. A 5-nm thick poly-Si seed layer was then prepared by the crystallization of an a-Si film using the vapor-induced crystallization process in a $NiCl_2$ environment. After removing surface oxide on the seed layer, a 45-nm thick a-Si film was deposited on the poly-Si seed layer by hot-wire chemical vapor deposition at $200^{\circ}C$. The epitaxial crystallization of the top a-Si layer was performed by the rapid thermal annealing (RTA) process at $730^{\circ}C$ for 5 min in Ar as an ambient atmosphere. Considering the needle-like grains as well as the crystallization temperature of the top layer as produced by the SERTA process, it was thought that the top a-Si layer was epitaxially crystallized with the help of $NiSi_2$ precipitates that originated from the poly-Si seed layer. The crystallinity of the SERTA processed poly-Si thin films was better than the other crystallization process, due to the high-temperature RTA process. The Ni concentration in the poly-Si film fabricated by the SERTA process was reduced to $1{\times}10^{18}cm^{-3}$. The maximum field-effect mobility and substrate swing of the p-channel poly-Si thin-film transistors (TFTs) using the poly-Si film prepared by the SERTA process were $85cm^2/V{\cdot}s$ and 1.23 V/decade at $V_{ds}=-3V$, respectively. The off current was little increased under reverse bias from $1.0{\times}10^{-11}$ A. Our results showed that the SERTA process is a promising technology for high quality poly-Si film, which enables the fabrication of high mobility TFTs. In addition, it is expected that poly-Si TFTs with low leakage current can be fabricated with more precise experiments.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.33 no.4
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• pp.225-235
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• 2020

Ultrasonic investigation of damage detection has been widely used for non-destructive testing of various concrete structures. This study focuses on damage detection analysis with the aid of wave propagation in two-phase composite concrete with aggregate (inclusion) and mortar (matrix). To fabricate a realistic simulation model containing a variety of irregular aggregate shapes, the mesh generation technique using an image processing technique was proposed. Initially, the domains and boundaries of the aggregates were extracted from the digital image of a typical concrete cut-section. This enables two different domains: aggregates and mortar in heterogeneous concrete sections, and applied the grids onto these domains to discretize the model. Subsequently, finite element meshes are generated in terms of spatial and temporal requirements of the model size. For improved analysis results, all meshes are designed to be quadrilateral type, and an additional process is conducted to improve the mesh quality. With this simulation model, wave propagation analyses were conducted with a central frequency of 75 kHz of the Mexican hat incident wave. Several void damages, such as needle-shaped cracks and void-shaped holes, were artificially introduced in the model. Finally, various formats of internal damage were detected by implementing energy mapping based signal processing.