• Biomolecules & Therapeutics
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• v.20 no.2
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• pp.239-244
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• 2012

This study examined the inhibitory effects of 4-guanidinobutyric acid (4GBA), an alkaloid, against gastric lesions by assessing the inhibition of Helicobacter pylori (H. pylori) and gastric cancer cells. Acute and chronic gastritis were also observed using HCl/ethanol (EtOH) and indomethacin-induced gastric lesion models, respectively. 4GBA inhibited the growth of H. pylori in a dose dependent manner, and showed acid-neutralizing capacity. In the pylorus ligated rats, 4GBA decreased the volume of gastric secretion and gastric acid output slightly, and increased the pH. 4GBA at a dose of 100 mg/kg reduced the size of HCl/EtOH-induced gastric lesions (70.8%) and indomethacin-induced gastric lesions (38.8%). The antigastritic action of 4GBA might be associated with the acid-neutralizing capacity, anti-H. pylori action, and decreased volume of gastric secretion. These results suggest that 4GBA might be useful in the treatment and/or protection of gastritis.

• Advances in nano research
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• v.15 no.2
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• pp.129-139
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• 2023

Emerge of nanotechnology has affected many aspects of our life and also triggers research studies in many fields. Nano-medicine are proven to be effective in encountering diseases. In the present study, aspects of the applications and effectiveness of nano-medicine in pediatrics patients are studied. In this regard, using experimental data of previous published researches, combination and dose of nano-medicines are optimized using response surface method and neural-fuzzy inference network. The input parameters of the selected multiple nano-medicines are dose and type and the output is the effectiveness of the combinations using IC50 parameter. A detailed parameter study is presented to observe effects of each inputs on the IC50. The results indicate that personalized scaling of nano-medicine is required in therapy of pediatric diseases such as cancers.

• The Korean Journal of Physiology and Pharmacology
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• v.5 no.4
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• pp.315-321
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• 2001

This study was aimed to evaluate the effects of quercetin and desferrioxamine on the development of the reflux esophagitis induced surgically, on gastric secretion and on lipid peroxidation which is a marker of oxidative stress. Omeprazole was used as a positive control drug. Omeprazole significantly and dose-dependently prevented the development of reflux esophagitis, but quercetin or desferrioxamine prevented only at high dose. Omeprazole significantly and dose-dependently inhibited the gastric acid secretion (gastric volume, pH and acid output), but quercetin or desferrioxamine did not inhibit. Malonyldialdehyde content, the end product of lipid peroxidation, increased significantly after the induction of reflux esophagitis. Omeprazole prevented lipid peroxidation. Quercetin and desferrioxamine inhibited the lipid peroxidation independent of their actions on gastric secretion. This result indicates that omeprazole confirmed preventing effect of rat reflux esophagitis, but quercetin and desferrioxamine inhibited esophagitis by reduction of lipid peroxidation irrespective of gastric acid secretion.

• Journal of radiological science and technology
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• v.19 no.2
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• pp.71-77
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• 1996

Studies were conducted to determine the clinical application of photodiode. We compared photodiode with ion-chamber as to change of tube potential, tube current, mAs and measured decreasing rate of penetration dose. When tube potential was changed from 60 kVp to 120 kVp, output of photodiode and ion-chamber were changed from 0.4 to 1.625, and 1.018 to 4.268, respectively. This was a good agreement to theory that $I=Kv^2it$(I is intensity, K is constant, v is tube potential, i is tube current, t is time). Characteristics for change of tube current and mAs were also a good agreement to theory. And comparison in decreasing rate of penetration dose was similar except above 6 cm in depth. Our results indicated that photodiode was a good instrument for relative measurement of radiation exposure, but we can not use the photodiode for absolute radiation dose.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.46 no.2
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• pp.1-6
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• 2009

The experimental results of exposing IGBT (Insulated Gate Bipolar Transistor) samples to gamma radiation source show shifting of threshold voltages in the MOSFET and degradation of carrier mobility and current gains. At low total dose rate, the shift of threshold voltage is the major contribution of current increases, but for more than some total dose, the current is increased because of the current gain degradation occurred in the vertical PNP at the output of the IGBTs. In the paper, the collector current characteristics as a function of gate emitter voltage (VGE) curves are tested and analyzed with the model considering the radiation damage on the devices for gate bias and different dose. In addition, the model parameters between simulations and experiments are found and studied.

• YAKHAK HOEJI
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• v.36 no.2
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• pp.173-179
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• 1992

The rhizoma of Zingiber officinale has been used as antiemetic, expectorants, stomachache relieving drugs and digestive accelerators. From the observation of antigastritic action of the methanol extract of the rhizoma, it was fractionated with hexane, chloroform, ethyl acetate and butanol, followed by bioassay on antigastritic and antiulcerative activity. The hexane and the chloroform fraction reduced significantly HCl ethanol induced gastric lesion at the dose of 370 and 210 mg/kg, p.o., respectively. On the gastric ulceration and gastric secretion in pylorus-ligated rats, the hexane fraction decreased the volume of gastric secretion and acid output, and also increased pH at the dose of 370 mg/kg, i.d.. It showed considerable curative ratio of acetic acid induced ulcer without inhibition of indomethacin induced gastric lesion. The methanol extract showed low acute toxicity with minimum lethal dose of more than 3000 mg/kg, p.o. in mice. In conclusion, Zingiberis rhizoma exhibited antigastric and antiulcerative activity which might be attributable to inhibition of gastric secretion. It is revealed that the active component may be present in the hexane fraction.

• Nuclear Engineering and Technology
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• v.51 no.3
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• pp.825-836
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• 2019

One of the most challenging safety precautions for workers in dynamic, radioactive environments is avoiding radiation sources and sustaining low exposure. This paper presents a sampling-based algorithm, DL-RRT*, for minimum dose walk-path re-planning in radioactive environments, expedient for occupational workers in nuclear facilities to avoid unnecessary radiation exposure. The method combines the principle of random tree star ($RRT^*$) and $D^*$ Lite, and uses the expansion strength of grid search strategy from $D^*$ Lite to quickly find a high-quality initial path to accelerate convergence rate in $RRT^*$. The algorithm inherits probabilistic completeness and asymptotic optimality from $RRT^*$ to refine the existing paths continually by sampling the search-graph obtained from the grid search process. It can not only be applied to continuous cost spaces, but also make full use of the last planning information to avoid global re-planning, so as to improve the efficiency of path planning in frequently changing environments. The effectiveness and superiority of the proposed method was verified by simulating radiation field under varying obstacles and radioactive environments, and the results were compared with $RRT^*$ algorithm output.

• Childhood Kidney Diseases
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• v.21 no.1
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• pp.26-30
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• 2017

Newborn infants with huge and highly vascular sacrococcygeal teratoma (SCT) are frequently subjected to renal hypoperfusion secondary to high-output cardiac failure. Any underlying renal dysfunction is a significant risk factor for the development of contrast-induced nephropathy (CIN). However, reports on CIN in infants are rare. I report here a case of a premature infant born at 28 weeks and 3 days of gestation with a huge SCT who survived preoperative embolization and surgical resection but presented with persistent non-oliguric renal failure that was suggestive of CIN. During radiological intervention, a contrast medium had been administered at about 10 times the manufacturer-recommended dose for pediatric patients. Despite hemodynamic stabilization and normalization of urine output immediately following surgery, the patient's serum creatinine and cystatin-C levels did not return to baseline until 4 months after birth. No signs of reflux nephropathy were observed in follow-up imaging studies. Dosing guidelines for the use of a contrast medium in radiological interventions should be provided for infants or young patients.

• Proceedings of the Korean Society of Medical Physics Conference
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• 2002.09a
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• pp.68-73
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• 2002

In standard teletherapy, a treatment plan is generated with the aid of a treatment planning system, but it is common to perform an independent monitor unit verification calculation (MUVC). In exact analogy, we propose and demonstrate that a simple and accurate MUVC in Intensity Modulated Radiotherapy (IMRT) is possible. We introduce a concept of Modified Clarkson Integration (MCI). In MCI, we exploit the rotational symmetry of scattering to simplify the dose calculation. For dose calculation along a central axis (CAX), we first replace the incident IMRT fluence by an azimuthally averaged fluence. Second, the Clarkson Integration is carried over annular sectors instead of over pie sectors. We wrote a computer code, implementing the MCI technique, in order to perform a MUVC for IMRT purposes. We applied the code to IMRT plans generated by CORVUS. The input to the code consists of CORVUS plan data (e.g., DMLC files, jaw settings, MU for each IMRT field, depth to isocenter for each IMRT field), and the output is dose contribution by individual IMRT field to the isocenter. The code uses measured beam data for Sc, Sp, TPR, (D/Mu)$\_$ref/ and includes effects from MLC transmission, and radiation field offset. On a 266 MHZ desktop computer, the code takes less than 15 sec to calculate a dose. The doses calculated with MCI algorithm agreed within +/- 3% with the doses calculated by CORVUS, which uses a 1cm x 1cm pencil beam in dose calculation. In the present version of MCI, skin contour variations and inhomogeneities were neglected.

• Journal of Korean Society on Water Environment
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• v.21 no.1
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• pp.21-28
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• 2005

The training and prediction modeling using an artificial neural network was implemented to predict the turbidity of treated water as well as to estimate the optimized feed concentration of polyaluminium chloride (PACl) in a water treatment plant. The parameters used in the input layers were pH, temperature, turbidity and alkalinity, while those in output layers were PACl and turbidity of treated water. Levenberg-Marquadt method of feedforward back-propagation perceptron in the neural network toolbox of MATLAB program was used in this study. Correlation coefficients of the training data with the measured data were 0.9997 for PACl and 0.6850 for turbidity and those of the testing data with measured data were 0.9140 for PACl and 0.3828 for turbidity, when four parameters at input layer, 12-12 nodes each at both the first and the second hidden layers, and two parameters(PACl and turbidity) at output layer were used. Although the predictability of PACl was improved, compared to that of the previous studies to use the only coagulant dose as output layer, turbidity in treated water could not be predicted well. Acquisition of more data through several years obtained with the advanced on-line measuring system could make the artificial neural network useful and practical in actual water treatment plants.