• Restorative Dentistry and Endodontics
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• v.27 no.6
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• pp.577-586
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• 2002

The purpose of this in vitro study was to compare the effects of root canal cleanness following two Ni-Ti rotary instruments with different rake angle. Thirty-six sound, extracted human premolars with single root were randomly divided into three groups. The used rotary instruments were HEROShaper (Group 1, Micro-Mega, Besancon, France, n=12) and ProFile (Group 2, Maillefer, Ballaigues, Switzerland, n=12). Control group (n=12) was only extirpated with barbed broach (Mani, Matsutani Seisakusho Co., Japan) Group 1 & 2 teeth were prepared to a #40/.04 taper at the apex followed by 1 mm using crown-down technique. After canal preparation and frequent irrigation with 5.25% sodium hypochlorite, the roots split longitudinally into a bucco-lingual direction. Root halves were cross-sectioned in apical third portion again. All root specimens were processed for SEM investigation and photographed. Separate evaluations by one endodontist were undertaken for smear layer on prepared walls with a five score-index for each using reference photograph in root halves. The penetration depth of smear layer into dentinal tubules was also estimated in the other halves. Following results were obtained: 1. Smear layer was observed on all the prepared walls with two experimental groups except control group. 2. Smear layer characteristics in two experimental groups; 1) HEROShaper group showed snowy, dusty appearance and were shown open dentinal tubuli on the prepared walls of almost specimens, and the thickness of smear layer covering onto dentinal surfaces was within 1-2 ${\mu}m$ in a few specimens. 2) ProFile group showed shiny, burnished appearance and complete root canal wall covered by a homogenous smear layer with no open dentinal tubuli in all specimens. The penetration of smear layer into dentinal tubules was found in all specimens and the thickness was at 2-4 ${\mu}m$ in all specimens. These results demonstrated that a completely clean root canal could not be achieved regardless of positive or negative rake angle, which is in accordance with the majority of previous studies on root canal cleanliness In conclusion, through irrigation with antibacterial solutions or chelating agents is recommended to remove the smear layer on prepared canal wall in spite of Ni-Ti instrumentation.

• Korean Journal of Environmental Agriculture
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• v.32 no.3
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• pp.193-200
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• 2013

BACKGROUND: Plant factory system of an artificial light type using Light-Emitting Diodes (LEDs), fluorescent light, or metal halide lamp instead of sun light is an ultimated method for plant production without any pesticides regardless of seasonal changes. The plant factory is also completely isolated from outside environmental conditions such as a light, temperature, or humidity compared to conventional greenhouse. Light-environment control such as a quality or quantity in the plant factory system is essential for improving the growth and development of plant species. However, there was little report that the effects of various light qualities provided by LEDs on Ledebouriella seseloides growth under the plant factory system. METHODS AND RESULTS: Ledebouriella seseloides seedlings transplanted at urethane sponge were grown in the plant factory system of a horizontal type with LED artificial lights for 90 days. Yamazaki solution for hydroponic culture of the seedlings was regularly irrigated by the deep flow technique (DFT) system on the culture gutters. Electrical Conductivity (EC) and pH of the solution was recorded at 1.4 ds/m and 5.8 in average, respectively during the experimental period. Number of unfolded leaves, leaf length, shoot fresh and dry weight of the seedlings were three times measured in every 30 days after beginning of the experiment. Blue LEDs, red LEDs, and fluorescent lights inside the plant factory were used as light sources. Conventional fluorescent lamps were considered as a control. In all the treatment, light intensity was maintained at $100{\mu}mol/m^2/s$ on the culture bed. Fresh weight of the seedlings was 3.7 times greater in the treatment with the mixture radiation of fluorescent light and blue+red LEDs (1:3 in energy ratio; Treatment FLBR13) than in fluorescent light treatment (Treatment FL). In FLBR13 treatment, dry weight per seedling was two times greater than in FL or BR11 treatment of blue+red LEDs (1:3 in energy ratio; Treatment BR11) during the culture period. Increasing in number of unfolded leaves was also significantly affected by the FLBR13 treatment comparing with BR11 treatment. CONCLUSION(S): Hydroponic culture of Ledebouriella seseloides seedlings was successfully achieved in the plant factory system with mixture lights of blue, red LEDs and fluorescent lights. Shoot growth of the seedlings was significantly promoted by the FLBR13 with the mixture radiation of fluorescent light, blue, and red LEDs under 1:3 mixture ratio of blue and red LEDs during the experimental period compared to conventional light conditions.

• Journal of Korean Neurosurgical Society
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• v.29 no.11
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• pp.1421-1428
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• 2000

Objectives : The aim of this study is to evaluate the sequential metabolic changes in experimental hydrocephalus and the clinical applicability to the diagnosis and prognosis of hydrocephalus using proton MR spectroscopy. Methods : Hydrocephalus was experimentally induced in 30 cats(2-3kg body weight) by injecting 1ml of sterile kaolin suspension(250mg/ml) into the cisterna magna. Proton MRS was performed with a 1.5 T MRI/MRS unit (Vision Plus, Siemens) at pre-treatment and at 1, 3, 7, 14, 21, and 28 days after the kaolin injection. PRESS(TR/TE＝1500/270msec) technique was employed. The major metabolites which include N-acetyl aspartate (NAA), creatine(Cr), choline(Cho), and lactate(Lac) were quantitatively analyzed and the relative concentrations ratios were evaluated. Multislice $T_2$-weighted images were also obtained using fast spin echo sequence(TR/TE＝ 2500/96msec) to monitor the morphologic changes along with progression of hydrocephalus. Results : Hydrocephalus was successfully induced in all 30 cats. Twenty five cats died within 3 days and one at the end of the second week. In all animals, the NAA/Cr ratios initially decreased during the acute stage. In 4 surviving cats, the NAA/Cr ratios initially decreased during the acute stage(<14 days) and then gradually increased to the prekaolin level as follows : pre-kaolin($1.49{\pm}0.04$), day 1($1.11{\pm}0.07$), day 7($1.17{\pm}0.04$), day 14($1.40{\pm}0.03$), day 21 ($1.46{\pm}0.06$), day 28($1.43{\pm}0.03$). These levels were relatively well correlated with the symptomatologic improvement. Lactate peak, which reflects the evidence of ischemia, did not appear throughout the entire period except in one case which expired at the end of the second week. Conclusions : The NAA/Cr ratio of the sequential proton MRS in kaolin-induced hydrocephalic cats reflects a metabolic aspect of the hydrocephalus at each stage. A decreased NAA level at the early stage is from both neuronal and axonal damage which may provide diagnostic information in the acute stage of hydrocephalus. In addition, the initial fall of NAA/Cr ratio and recovery in the late stage, when no lactate peak emerges, may suggest that the main insult of the parenchyma is not to the neuron itself but to the axon, which may be related to a good prognosis. However, emergence of the lactate peak and unrecoverable NAA/Cr at the end of the acute phase may be a poor prognostic factor. In the chronic stage, recovery of NAA/Cr ratio may provide a diagnostic clue for the differentiation between hydrocephalus and cortical atrophy.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.28 no.2
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• pp.95-110
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• 2006

The treatment for oral and maxillofacial carcinoma with chemotherapeutic agents is evaluated by many effective methods to reduce the tumor mass and cancer cell proliferation. However these chemotherapy have many serious side effects, such as bone marrow suppression, renal toxicity, G-I troubles. Therefore a possible approach to develop a clinically applicable chemotherapeutic agent is to screen anticancer activity of Taxol which is known to have very little side effect and have been used to breast cancer and ovarian carcinoma. Taxol is a new anti-microtubular anti-cancer agent extracted from the bark of the Pacific yew, Taxus brevifolia. Paclitaxel(Taxol) acts by promoting tubulin polymerization and over stabilizing microtubules agianst depolymerization. Despite the constant improvements of methods of the cancer treatment especially chemotherapy, the rate of cancer metastasis and recurrent are not decreased. Thus the investigation of new drug which have very little side effect and a possible clinically application continues to be a high priority. Considering that the Taxol have shown very effective chemotherapeutic agent with relatively low toxicity in many solid tumors, it deserves to evaluate its efficacy in oral squamous cell carcinoma. In this study, to investigate the in-vivo and in-vitro anti-cancer efficacy of Taxol in oral squamous cell carcinoma and lastly, the potency of Paclitaxel in the clinical application for oral cancer was evaluated. In vivo study, after HN22 cell line were xenografted in nude mice, the growth of tumor mass was observed, 3 mg/Kg taxol was injected intraperitoneally into nude mice containing tumor mass. The methods of these study were measurement of total volume of tumor mass, histopathologic study, immunohistochemical study, drug resistance assay, growth curve, MTT assay, flow cytometry, cDNA microarray in vivo and in vitro. The results were obtained as following. 1. The visual inspection of the experimental group showed that the volume of the tumor mass was slightly decreased but no significant difference with control group. 2. Ki-67 index was decreased at weeks 4 in experimental group. 3. Microscopic view of the xenografted tumor mass showed well differentiated squamous cell carcinoma and after Taxol injection, some necrotic tissue was seen weeks 4. 4. The growth curve of the tumor cells were decreased after 1day Taxol treatment. 5. According to the MTT assay, HN22 cell line showed relative drug resistancy above $5\;{\mu}g/ml$ concentrations of Taxol. 6. In drug resistance assay, the decrease of cell counts was seen relatively according to concentration. 7. In Flow cytometry, G2M phase cell arrests were seen in low concentration of the Taxol, while S phase cell arrests were seen in high concentration of the Taxol. 8. Using cDNA microarray technique, variable gene expression of ANGPTL4, TXNRD1, FAS, RRAGA, CTGF, CYCLINEA, P19, DUSP5, CEBPG, BTG1 were detacted in the oral squamous cell carcinoma cell after taxol treatment. In this study paclitaxel is effective against oral squamous cell carcinoma cell lines in vitro, but week effect was observed in vivo. So we need continuous study about anticancer effect of taxol in vivo in oral squamous cell carcinoma.

• Progress in Medical Physics
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• v.26 no.4
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• pp.215-222
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• 2015

In this work, we performed a proof-of-concept experiment for phase-contrast x-ray imaging (PCXI) based on a single antiscatter grid and a polychromatic x-ray source. We established a table-top setup which consists of a focused-linear grid having a strip density of 200 lines/inch, a microfocus x-ray tube having a focal-spot size of about $5{\mu}m$, and a CMOS-type flat-panel detector having a pixel size of $48{\mu}m$. By using our prototype PCXI system and the Fourier demodulation technique, we successfully obtained attenuation, scattering, and differential phase-contrast images of improved visibility from the raw images of several selected samples at x-ray tube conditions of $90kV_p$ and 0.1 mAs. Further, fusion image (e.g., the attenuation+the scattering) may have an advantage in displaying details of the sample's structures that are not clearly visible in the conventional attenuation image. Our experimental results indicate that single-grid-based approach seems a useful method for PCXI with great simplicity and minimal requirements on the setup alignment.

• Parasites, Hosts and Diseases
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• v.26 no.1
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• pp.39-44
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• 1988

A pathogenic free-living amoeba, Naegleria fowleri, is a causative protozoan parasite of primary amebic meningoencephalitis in human and experimental animals. It is known that humoral and cellular immunity contribute as the defence mechanism of host against this organism. Recently splenectomy has been argued on its effect on host defence mechanisms. The present study was aimed to observe the enact of immunization in splenectomized mice. For immunization, $5~10{\times}10^5$ trophozoites of Naegleria fewleri o 359 were intraperitoneally inoculated once a week for two weeks to BALB/c mice, and $5~10{\times}10^4$ of ameba trophozoites were intranasally inoculated for infection after splenectomy and/or immunization. ELISA technique was applied for the detection of seum IgG antibody levels. Experimental animals were divided into 4 groups; I. splenectomized and immuniEed; ll. splenectomized only; III. immunized only; IV. not splenectomized nor immunized. The results obtained were as follows: 1. Mortality rates of splenectomized and immunized mice in group I (38.1%) and immunized only in group III (25.0%) were lower than those of not immunized mice in group II (50%) and control group, IV (46.4%). 2. Survival times of mice in group I, II, III and IV were $20.1{\pm}3.6$, $17.3{\pm}4.5$, $20.4{\pm}7.0$ and $19.6{\pm}7.6$ days respectively, and there were no significant differences between them. 3. ELISA values (absorbance at 492nm) of group I (1, $10{\pm}0.29$) and group III ($1.31{\pm}0.28$) were significantly higher than that of group IV($0.24{\pm}0.37$) at day 31 of infection (p<0.05). Conclusively, it is presumed that humoral immunity against N. fowleri may operate as ever, after immunization, even though the mouse was splenectomized.

• Childhood Kidney Diseases
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• v.2 no.2
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• pp.138-144
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• 1998

Purpose : The use of cyclosporine and mitomycin in various immunologic or neoplastic disorders has been known to cause wide-ranged nephrotoxic effects including thrombotic microangiopathy. However, the mechanism of nephrotoxicity of these drugs has not been studied adequately, so that present experimental study has been undertaken to find out whether these drugs can cause direct damage to the kidney and to clarify the pathogenetic mechanism of nephrotoxic effect of these drugs. Materials and methods : Sprague-Dawley rats weighing 250-300 gm were used for experimental animals and unilateral renal perfusion technique, modified from the method described by Hoyer et al was used. Isolation of left kidney from systemic circulation was made by clamping aorta and left renal vein and a hole was punctured in the anterior wall of the left renal vein. Cyclosporine (2.5 mg in 4 ml solution) and mitomycin (1.6 mg in 4ml solution) were infused through left renal artery and normal saline was used in control rats. Forty-eight hours after infusion of the drugs, animals were sacrificed and left kidney removed and processed for histologic examination. Total ischemic time of left kidney was less than 15 minutes: Results : Cyclosporine-perfused group showed severe swelling of glomerular endothelial ceil along with swelling of glomerular epithelial cell and interstitial vascular endothelial cell. Mitomycin-perfused group also showed severe swelling of glomerular endothelial and epithelial cells. And in addition to these findings, they demonstrated platelets aggregation, swelling and degranulation of platelets and fibrin accumulation in some of the capillaries, indicating occurrance of thrombotic microangiopathy. Conclusion : present experiment indicates that cyclosporine and mitomycin can cause direct toxic injury to renal endothelial cell. And this direct toxic damage to endothelial cell seems to be an important initiating event for the development of thrombotic microangiopathy.

• Asian-Australasian Journal of Animal Sciences
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• v.21 no.1
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• pp.107-119
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• 2008

To determine the true digestible phosphorus (TDP) requirement of growing pigs, two experiments were designed with the experimental diets containing five true digestible P levels (0.16%, 0.20%, 0.23%, 0.26% and 0.39%) and the ratio of total calcium to true digestible P (TDP) kept at 2:1. In Experiment 1, five barrows (Duroc${\times}$Landrace${\times}$Yorkshire) with an average initial body weight of 27.9 kg were used in a $5{\times}5$ Latin-square design to evaluate the effect of different dietary P levels on the digestibility and output of P and nitrogen. In Experiment 2, sixty healthy growing pigs (Duroc${\times}$Landrace${\times}$Yorkshire) with an average body weight (BW) of 21.4 kg were assigned randomly to one of the five dietary treatments (12 pigs/diet), and were used to determine the true digestible phosphorus (TDP) requirement of growing pigs on the basis of growth performance and serum biochemical indices. The results indicated that the true digestibility of P increased (p<0.05) linearly with increasing dietary TDP level below 0.26%. The true P digestibility was highest (56.6%) when dietary TDP was 0.34%. Expressed as g/kg dry matter intake (DMI), fecal P output increased (p<0.05) linearly with increasing P input. On the basis of g/kg fecal dry matter (DM), fecal P output was lowest for Diet 4 and highest (p<0.05) for Diet 5. The apparent digestibility of crude protein (CP) did not differ (p>0.05) among the five diets, with the average nitrogen output of 12.14 g/d and nitrogen retention of 66% to 74% (p>0.05), which suggested that there was no interaction between dietary P and CP protein levels. During the 28-d experimental period of Experiment 2, the average daily gain (ADG) of pigs was affected by dietary TDP levels as described by Eq. (1): $y=-809,532x^4+788,079x^3-276,250x^2+42,114x-1,759$; ($R^2=0.99$; p<0.01; y = ADG, g/d; x = dietary TDP, %), F/G for pigs by Eq. (2): $y=3,651.1x^4-3,480.4x^3+1,183.8x^2-172.5x+10.9$ ($R^2=0.99$; p<0.01; y = F/G; x = dietary TDP, %), and Total P concentrations in serum by Eq. (3): $y=-3,311.7x^4+3,342.7x^3-1,224.6x^2+195.6x-8.7$ (R2 = 0.99; p<0.01; y = total serum P concentration and x = dietary TDP, %). The highest ADG (782 g/d), the lowest F/G (1.07) and the highest total serum P concentration (3.1 mmol/L) were obtained when dietary TDP level was 0.34%. Collectively, these results indicate that the optimal TDP requirement of growing pigs is 0.34% of the diet at a total Ca to TDP ratio of 2:1.

• Journal of Acupuncture Research
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• v.22 no.3
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• pp.123-135
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• 2005

Objective : The aim of this study was to rivew systemically literature and clinical trials in the treatment of urinary incontinence or lower urinary tract syndrome(LUTS). Methods : Computerized literature searches were carried out on two electronic database, and computerized searching on some korea oriental medicine journals in library of Kyung-Hee Medical center. Results : 1. Three reports of review study, six reports of experimental study and fourteen reports of clinical trials were collected and reviewed. Three reports of review study were all printed in the korea oriental medicine journal. From 2000, researches and studies have been increased in quantity and improved in quality. 2. Urinary disturbance include variable symptoms of lower urinary tract symptoms, urinary incontinence, in theaspect of Oriental medicine these symptoms are anurin, dysuria, urinary incontinence, nochumal enuresis, uracratia and so on. 3. Roughly physiological procedure of Acupuncture in Treatment of Urianry Disturbance may be that effect of acupuncture stimulation for parasympathetic nerve, sleep-arousal system in cerebrum, pontine/spinal urination center and pudendal/pelvic nerve affect bladder in expansion of bladder capacity, inhibition of urinary contraction and affection in periurethral muscle by continuous excitement of spinal annular circuit and synapse of neuron. 4. Clinical result for acupuncture treatment in urinary disturbance is summarized that acupuncture treatment in urianation disturbance of Neurogenic Bladder, Incontinence, Cycitis, Nocturnal Enuresis, Prostatitis/Pelvic Pain Syndrom and so on is significant clinical trials and technique. Conclusion : Hereafter, in the old age society these variable urinary disturbance patients are increased and desire of treatment may be also increased. So study of various and formal treatment and tecnnique is needed.

• Journal of the Korea Concrete Institute
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• v.14 no.1
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• pp.126-135
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• 2002

Plate bonding technique has been widely used in strengthening of existing concrete structures, although it has often a serious problem of premature falure such as interface separation and rip-off. However, this premature failure problem has not been well explored yet especially in view of local failure mechanism around the interface of plate ends. The purpose of the present study is, therefore, to identify the local failure of strengthened plates and to derive a separation criterion at the interface of plates. To this end, a comprehensive experimental program has been set up. The double lap pull-out tests considering pure shear force and half beam tests considering combined flexure-shear force were performed. The main experimental parameters include plate thickness, adhesive thickness, and plate end arrangement. The strains along the longitudinal direction of steel plates have been measured and the shear stress were calculated from those measures strains. The effects of plate thickness, bonded length, and plate end treatment have been also clarified from the present test results. Nonlinear finite element analysis has been performed and compared with test results. The Interface properties are also modeled to present the separation failure behavior of strengthened members. The cracking patterns as well as maximum failure loads agree well with test data. The relation between maximum shear and normal stresses at the interface has been derived to propose a separation failure criterion of strengthened members. The present study allows more realistic analysis and design of externally strengthened flexural member with steel plates.