• Progress in Medical Physics
• /
• v.12 no.2
• /
• pp.125-131
• /
• 2001

We was investigate the dosimetric characteristics of the virtual wedge and it compared to the conventional fixed wedge. Also we was evaluate the quality factor of the experimental multi-channel dosimetry system for virtual wedge. Recently virtual wedge technique and wedge fraction methods are available through the computer controlled asymmetric collimator or the independent jaw in medical linear accelerator for radiation therapy. The dosimetric characteristics are interpreted by radiation field analyzer RFA-7 system and PTW-UNIDOS system. Experimental multi-channel dosimetry system for virtual wedge was consists of the electrometer, the solid detector and array phantom. The solid detectors were constructed using commercially diodes for the assessment of quality assurance in radiotherapy. And it was used for the point dose measuring and field size scanning. The semiconductor detector and ion chamber were positioned at a dmax, 5 cm, 10 cm, 20 cm depth and its specific ratio was determined using a scanning data. Wedge angles in fixed and virtual type are compared with measurements in water phantom and it is shown that the wedge angle 15$^{\circ}$, 30$^{\circ}$, 45$^{\circ}$were agree within 1$^{\circ}$ degree in 6, 10 MV photon beams. In PDD and beam flatness, experimental multi-channel disimetry system was capable of reproduceing the measured values usually to within $\pm$2.1% the statistical uncertainties of the data. It was used to describe dosimetric characteristics of virtual wedge in clinical photon beams. Also we was evaluate optimal use of the virtual wedge and improve the quality factor of the experimental multi-channel dosimetry system for virtual wedge.

• Journal of Dental Rehabilitation and Applied Science
• /
• v.16 no.3
• /
• pp.197-210
• /
• 2000

Surface roughness is one of implant surface topography and it's found that surface roughness characterizations, such as surface energy, oxide layer thickness and its chemical composition, are closely correlated if the roughness is changed. Several studies showed the importance of analyzing surface structure so the surface structure of thread implant was analyzed to measure the implant quality exactly. In this study, surface roughness of 4 implants - MK $II^{(R)}$(Nobel Biocare), $RBM^{(R)}$(Life-Core, USA), $Osseotite^{(R)}$(3i, USA), $TPS^{(R)}$(Life-Core, USA) - were measured using $Accura^{(R)}$ and 40 implants were installed into 4 sets of ten bovine ribs based on the parameters from the measurements. From this test, the following conclusions for the initial stability were drawn by measuring and comparing RFA, Periotest Value (PTV), Removal Torgue Value (RTV). 1. $R_a$ value in surface roughness measurement was increasing by the order of $MKII^{(R)}$, $Osseotite^{(R)}$, $RBM^{(R)}$, $TPS^{(R)}$ and $R_q$ value was the same order. 2. $R_q$ value in each section was observed to increase by the order of $MKII^{(R)}$, $Osseotite^{(R)}$, $RBM^{(R)}$, $TPS^{(R)}$ in top and $MKII^{(R)}$, $RBM^{(R)}$, $Osseotite^{(R)}$, $TPS^{(R)}$ in mid-section but the value of $MKII^{(R)}$ bottom was the lowest, followed by $Osseotite^{(R)}$, $RBM^{(R)}$ and $TPS^{(R)}$. 3. RFA increased by the order of $RBM^{(R)}$(7042Hz), $MKII^{(R)}$(7047Hz), $Osseotite^{(R)}$(7076Hz), $TPS^{(R)}$(7168Hz) and there was no significance between each group. 4. PTV was increasing by the order of $MKII^{(R)}$(-1.62), $TPS^{(R)}$(-1.92), $Osseotite^{(R)}$ & $RBM^{(R)}$(-2.08) and there was no significance, either. 5. Removal torque in RTV measurement showed the increasing order of $MKII^{(R)}(5.31kgf{\cdot}cm)$, $Oeeotite^{(R)}(5.71kgf{\cdot}cm)$, $TPS^{(R)}(5.92kgf{\cdot}cm)$ and $RBM^{(R)}(7.24kgf{\cdot}cm)$ and there was no significance among groups. Above observations explains that surface roughness does not make any impact on the initial stability of implants installation.

• KSBB Journal
• /
• v.21 no.2
• /
• pp.90-95
• /
• 2006

Escherichia coli harboring pAC-LYCO4 and pDdxs was used for lycopene production. Three wild type strains of E. coli OW1, MG1655, and W3110 were compared with DH5${\alpha}$ used before for lycopene production. Lycopene productivity of E. coli MG1655 was similar to DH5${\alpha}$ and the highest among those wild type strain. Therefore, MG1655 strain was used for random transposon and NTG mutagenesis to increase lycopene productivity. Through transposon mutation, five transposon mutants with increased lycopene productivity were obtained. It was found that genes knocked out by transposon insertion were treB in Tn1 mutant, B2436 in Tn2 mutant, and rfaH in Tn3, 4, and 5 mutants. Lycopene productivity was the highest in Tn4 mutant among the Tn mutants, which was 6-fold and 8-fold higher in lycopene concentration and content, respectively, in comparison with those obtained with wild type strain. NTG4 mutant was acquired with NTG mutation. The highest lycopene productivity of 6 mg/L and 4 mg/g DCW was obtained from the NTG4 mutant when arabinose of 0.013 mM was added for induction of dxs, rate-limiting gene of MEP pathway. The lycopene productivity of NTG4 mutant was increased 18-fold and 12-fold in lycopene concentration and content, respectively when comparing with the wild type strain.

• Asian Pacific Journal of Cancer Prevention
• /
• v.17 no.6
• /
• pp.2857-2860
• /
• 2016

Background: Chronic hepatitis B (CHB) infection is one of the important causes of hepatocellular carcinoma (HCC) in Thailand, involved in the pathogenesis and leading to a development of HCC with or without cirrhotic changes of the liver. This study was aimed to investigate the predictive factors for HCC among CHB patients in a tertiary care center in Thailand. Materials and Methods: We conducted a retrospective study of CHB patients with or without HCC during the period of January 2009 and December 2014 at Thammasat University Hospital, Pathumthani, Thailand. Data on clinical characteristics, biochemical tests and radiologic findings were collected from review of medical records. Results: A total of 266 patients were diagnosed with CHB in Thammasat university hospital during the study period. However, clinical information of only 164/266 CHB patients (98 males, 66 females with mean age of 49.4 years) could be completely retrieved in this study. The prevalence of HCC in CHB infection in this study was 38/164 (23.2%). CHB patients with HCC had a mean age older than those without HCC (59.5 vs 47 years, P-value = 0.01). Furthermore, history of upper GI bleeding, tattooing, blood transfusion, and chronic alcoholism were significantly more common in CHB patients with HCC than patients without HCC (13.2% vs 3.2% P-value 0.03, OR = 4.6, 95%CI = 1.2-18.1, 20% vs 3.9%, P-value = 0.01, OR= 6.1, 95% CI= 1.6-23.6, 20% vs 6.3%, P-value = 0.03, OR = 3.8, 95%CI =1.1-12.7, 62.2% vs 30.3%, P-value <0.0001, OR = 3.7, 95%CI= 1.7-8.1 respectively). Interestingly, more CHB patients with HCC had evidence of cirrhosis than those without HCC (78.9% vs 20.4%, P-value <0.0001, OR = 14.6, 95%CI = 5.8-36.7). In CHB patients with HCC, surgical therapy provided longer survival than radiofrequency ablation (RFA) (72 vs 46.5 months, P-value= 0.04). The mean survival time after HCC diagnosis was 17.2 months. Conclusions: HCC remains a major problem among patients with CHB infection in Thailand. Possible risk factors are male gender, history of upper GI bleeding, chronic alcoholism, tattooing, blood transfusion and evidence of cirrhosis. For early stage HCC patients, surgical treatment provided longer survival time than RFA. Most HCC patients presented with advanced disease and had a grave prognosis. Appropriate screening of CHB patients at risk for HCC might be an appropriate approach for early detection and improvement of long-term outcomes.

• Journal of the Korean Society of Radiology
• /
• v.79 no.5
• /
• pp.264-270
• /
• 2018

Purpose: To evaluate the effect of portal hypertension on the tumor recurrence in patients with hepatocellular carcinoma (HCC) and without hepatic decompression following radiofrequency ablation (RFA). Materials and Methods: Treatment-naïve HCC patients within the Milan criteria and with Child-Pugh class A were included in this study, who had performed RFA in our hospital between January 2010 and March 2017. Univariate and multivariate analyses using the Cox proportional hazard model were performed to find the predictors of local or distant tumor recurrence. Results: Overall, 178 patients were included in this study. Median follow-up period was 40.2 months. The difference in the local tumor progression rates depending on the absence or presence of portal hypertension was not statistically significant (p = 0.195). The 1-, 3-, and 5-year distant intrahepatic tumor spread rates were 6.6%, 29.5%, and 537% in patients without portal hypertension, and 23.4%, 51.9%, and 63.6% in patients with portal hypertension, respectively. The difference was statistically significant (p = 0.011). Univariate and multivariate analysis showed that portal hypertension was an independent predictor for distant intrahepatic tumor spread (p = 0.008). Conclusion: For HCC patients with Child-Pugh class A, portal hypertension adversely affected distant intrahepatic tumor progression.

• Journal of Digestive Cancer Research
• /
• v.2 no.2
• /
• pp.75-77
• /
• 2014

Ampulla of Vater (AOV) cancer is rare malignant tumor which arises within the vicinity of the AOV. Metastatic AOV adenocarcinoma has poor prognosis, with an overall survival rate at 2 years ranging from 5 to 10%. The Surveillance, Epidemiology and End Results Program of the National Cancer Institute indicated that lymph node metastasis was present in as many as half of patients which were associated with poor prognosis and liver was the second most common site of distant metastasis in AOV cancer. In this case report, we describe a case of complete resolution of AOV cancer, which was already spread to retroperitoneal lymph node and liver. The patient underwent gemcitabine plus cisplatin chemotherapy for palliative aim. After 12 month of chemotherapy, image study showed partial remission, so intraoperative radiofrequency ablation therapy and pylorus preserving pancreaticoduodenectomy was done. AOV cancer was completely resected and the patient was followed up without recurrence for 7 months.

• Journal of the Optical Society of Korea
• /
• v.18 no.6
• /
• pp.657-662
• /
• 2014

We demonstrate a simulation of a parallel hybrid fiber amplifier in the C+L-band with a gain controlling technique. A variable optical coupler is used to control the input signal power for both EDFA and RFA branches. The gain spectra of the C+L-band are flattened by optimizing the coupling ratio of the input signal power. In order to enhance the pump conversion efficiency, the EDFA branch was pumped by the residual Raman pump power. A gain bandwidth of 60 nm from 1530 nm to 1590 nm is obtained with large input signal power less than -5 dBm. The gain variation is about 1.06 dB at a small input signal power of -30 dBm, and it is reduced to 0.77 dB at the large input signal power of -5 dBm. The experimental results show close agreement with the simulation results.

• Journal of the Korean Ceramic Society
• /
• v.53 no.2
• /
• pp.234-240
• /
• 2016

Energetically-modified material using reject fly ash (RFA), generated from thermal power plants, was manufactured to investigate the effect of the material on the physical and chemical characteristics of cement mortar. In order to modify reject fly ash, a vibration mill was used. Particle size, grain shape, and crystal structure of the ash were analyzed. Then, the compressive strength of the mortar using energetically-modified reject fly ash (ERFA) was measured. Microstructure and X-ray diffraction (XRD) patterns were also used in the analysis. As the replacement rate of ERFA increased, the value of the compressive strength tended to decrease. However, it was found that the compressive strength values of 7 and 28 days-cured specimens were higher than those of conventional ordinary Portland cement (OPC) mortar with 10 % replacement rate condition.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2000.05b
• /
• pp.13-16
• /
• 2000

In this study, we have fabricated nonequilibrium $Fe_{85.6}Zr_{3.3}B_{5.7}Ag_{5.4}$ thin film, which contains an additional insoluble element Ag, by using DC magnetron sputtering method. We have investigated the magnetic properties of amorphous $Fe_{85.6}Zr_{3.3}B_{5.7}Ag_{5.4}$ thin film as a function of rotational field annealing(RFA). After deposition, the amorphous $Fe_{85.6}Zr_{3.3}B_{5.7}Ag_{5.4}$ thin film annealed by rotational field annealing method at $350^{\circ}C$ for an hour was founded to have high permeability of 8680 of 100 MHz, 0.2 mOe, low coercivity of 0.86 De and very low core loss of 1.3 W/cc at 1 MHz, 0.1T.

• Proceedings of the Ginseng society Conference
• /
• 1998.06a
• /
• pp.115-126
• /
• 1998

Four new dammarnae-glycosides named ginsenosides Rgs, Rh4, RsB and Rf2 have been isolated 1'rom Korean red ginseng, the root of Panax ginseng C. A. Meyer (Araliaceae) and their chemical structures have been elucidated by chemical and spectroscopic methods, including'H-'H COSY, HMQC, HMBC, NOESY, as 3-0- [$\beta$-D-glucopyranosyl(1 ~2)-$\beta$-D-glucopyranosyl] dammar-20(22) , B4-diene-3P,12P-diol (ginsenoside Rgs),6-0-$\beta$-D-glucopyranosyl-dammar-20(22),24-diene-3P,6P, 12P-triol (ginsenoside Rh4),3-0- [6" -0-acetyl-D-glucopyranosyl(1 ~2)--D-glucopyranosyl] 20(5)- protopanaxadiol (ginsenoside Rs3) and 6-0- [u-L-rhamno-pyranosyl(1 ~2)-$\beta$-D-glucopyranosyl] dammarane -3$\beta$, 6a, 12 $\beta$, 20(R),25-pentol(ginsenoslde Rfa). The absolute stereo structure of a double bond at C-20(22) was determined as entgegen type by applying NOESY.OESY.