• Journal of Pharmaceutical Investigation
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• v.19 no.3
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• pp.163-171
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• 1989

To investigate the protein binding characteristics of cephalothin, the effects of ionic strength, pH and temperature on the binding of cephalothin to bovine serum albumin (BSA) were studied by UV difference spectrophotometric method. With increasing ionic strength at constant PH and temperature, association constant decreased, but the number of binding sites sites was about 2 constantly. It may be deduced that the binding process is not only due to electrostatic forces. And the increased association constant at high ionic strength is explained by conformational changes of BSA from complex to subunits. The pH effect on the affinity of interaction indicated that the binding affinity of drug is higher in the neutral region than in the alkaline region. And, at high pH value, the number of binding sites decreased from 2 to 1 because of the conformational changes of BSA in alkaline region. The decrease in binding affinity of BSA to drug with increasing temperature was characteristic of an exothermic reaction. And the negative sign of ${\Delta}G^{\circ}$ meant that the binding process occurs spontaneously under the experimental conditions. In cephalothin-BSA complex formation, since the net enthalpy change value and entropy change value are positive, it is assumed that hydrophobic bindings are predominant in this binding process.

• Molecules and Cells
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• v.42 no.10
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• pp.711-720
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• 2019

Sink strength optimizes sucrose import, which is fundamental to support developing seed grains and increase crop yields, including those of rice (Oryza sativa). In this regard, little is known about the function of vacuolar invertase (VIN) in controlling sink strength and thereby seed size. Here, in rice we analyzed mutants of two VINs, OsVIN1 and OsVIN2, to examine their role during seed development. In a phenotypic analysis of the T-DNA insertion mutants, only the OsVIN2 mutant osvin2-1 exhibited reduced seed size and grain weight. Scanning electron microscopy analysis revealed that the small seed grains of osvin2-1 can be attributed to a reduction in spikelet size. A significant decrease in VIN activity and hexose level in the osvin2-1 spikelets interfered with spikelet growth. In addition, significant reduction in starch and increase in sucrose, which are characteristic features of reduced turnover and flux of sucrose due to impaired sink strength, were evident in the pre-storage stage of osvin2-1 developing grains. In situ hybridization analysis found that expression of OsVIN2 was predominant in the endocarp of developing grains. A genetically complemented line with a native genomic clone of OsVIN2 rescued reduced VIN activity and seed size. Two additional mutants, osvin2-2 and osvin2-3 generated by the CRISPR/Cas9 method, exhibited phenotypes similar to those of osvin2-1 in spikelet and seed size, VIN activity, and sugar metabolites. These results clearly demonstrate an important role of OsVIN2 as sink strength modulator that is critical for the maintenance of sucrose flux into developing seed grains.

• Korean Journal of Clinical Pharmacy
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• v.31 no.3
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• pp.231-236
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• 2021

Background: Sarcopenia is a skeletal muscle disorder that involves the loss of muscle mass and function. Handgrip strength (HGS) is the most commonly used tool to assess muscle strength to diagnose sarcopenia. HGS is also associated with various diseases and health outcomes. Thus, we aimed this study to examine the HGS status in Korean adults and relevant factors of HGS. Methods: Data was obtained from the 7th Korea National Health and Nutrition Examination Survey (KNHANES), a population-based nationwide survey. The estimated mean value of HGS was calculated in each age group. The mean HGS in men and women aged over 40 was compared according to the household income level, lifestyle factors, and comorbidities. Results: A total of 16,708 participants were included in this study. The mean HGS showed a maximum value in the 30s for both men and women, and then tended to decrease with increasing age. When analyzed for people aged 40 or older, the mean HGS was significantly higher in the current or past smoker, drinker, and aerobic exercise groups in both men and women. The mean HGS was lower in the group with comorbidities such as hypertension, dyslipidemia, type 2 diabetes, and bone diseases. Conclusion: Our study found that the mean HGS was significantly different between those with and without underlying chronic diseases. In groups with relevant comorbidities, close monitoring for the development of sarcopenia and taking preventive measures such as exercise and nutritional support may be recommended.

• Journal of the Korean Geotechnical Society
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• v.34 no.12
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• pp.83-92
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• 2018

The lapse of time may cause in the slope structure various deterioration phenomenon progresses in the ground of slope, and collapse due to deterioration of strength, resulting in a decrease in the service life. The approach to slope stability due to the ground deterioration is a different concept from the existing limit equilibrium analysis, which is limited to the physical characteristics and geometrical structure of ground. In this study, we conducted a comparative analysis of various literature studies related to the slope failure characteristics and behaviors to presented the optimal formulas for shear strength reduction, such as the exponential function, the logarithmic function and the inverse hyperbolic function. And then a case study was performed on cut slope of Gyeongbu High Speed Rail construction site along the Yangsan fault zone, where the slope failure of shale layer vulnerable to deterioration occurred. As a result, it was confirmed that landslide occurred due to reduction of shear strength by deterioration, as safety factor is approx. 1.0 at the time when the slope failure occurred. Based on the comprehensive case study, as a quantitative approach to the evaluation of slope stability due to deterioration of ground, finally we propose a method for evaluating slope stability with optimal strength reduction curves.

• Journal of The Korean Society of Integrative Medicine
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• v.9 no.1
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• pp.123-131
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• 2021

Purpose : The time spent using smart devices is constantly increasing, particularly in recent times. Using smart devices for a long time with an incorrect posture may lead to cerebral palsy (CP), instability, and abnormal muscle tone. Therefore, we aimed to investigate the relationships among cervical instability, deep neck flexor (DNF) activity, range of motion (ROM), and muscle tonus. Methods : Fifty subjects with CP participated in this study, and they were physiotherapists at W Hospital in Daejeon. Those who voluntarily participated in the research were selected as candidates who fulfilled the selection criteria. According to an instability test, 25 subjects were assigned to the instability and control groups. All subjects first underwent the instability test to be allocated to the appropriate group. Those in the instability group tested positive on the instability test. The Neck Disability Index (NDI), ROM, muscle tone, and DNF activity were measured to evaluate their relationships. The DNF strength and endurance were measured using a cranio-cervical flexion test. The upper trapezius (UT), sternocleidomastoid (SCM), and suboccipital (SO) muscle tones were measured using a contact soft tissue tone measuring instrument. The statistical significance level was set to .05. Results : There were significant differences in the flexion, extension, and rotation of the cervical ROM (CROM) between the two groups (p<.05). The SCM, UT, and SO muscle tones were significantly different between the two groups (p<.05). The DNF strength and endurance showed a significant difference between the two groups (p<.05). Conclusion : We found that there were significant increases in the CROM and muscle tone and decrease in the DNF strength and endurance in the instability group. This indicated that cervical instability is affected by the DNF strength and endurance. We may recommend DNF exercises in cases of cervical instability in clinical environments.

• Geomechanics and Engineering
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• v.24 no.2
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• pp.179-191
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• 2021

In this study, the strength and failure mechanism of red sandstones with combined defects were investigated by uniaxial compression tests on red sandstones with different crack angles using two-dimensional particle flow code numerical software, and their mechanical parameters and failure process were studied and analyzed. The results showed that the mechanical characteristics such as peak strength, peak strain, and elastic modulus of the samples with prefabricated combined defects were significantly inferior than those of the intact samples. With increasing crack angle from 15° to 60°, the weakening area of cracks increased, elastic modulus, peak strength, and peak strain gradually reduced, the total number of cracks increased, and more strain energy was released. In addition, the samples underwent initial brittle failure to plastic failure stage, and the failure form was more significant, leading to peeling phenomenon. However, with increasing crack angle from 75° to 90°, the crack-hole combination shared the stress concentration at the tip of the crack-crack combination, resulted in a gradual increase in elastic modulus, peak strain and peak strength, but a decrease in the number of total cracks, the release of strain energy reduced, the plastic failure state weakened, and the spalling phenomenon slowed down. On this basis, the samples with 30° and 45° crack-crack combination were selected for further experimental investigation. Through comparative analysis between the experimental and simulation results, the failure strength and final failure mode with cracks propagation of samples were found to be relatively similar.

• Korean Journal of Metals and Materials
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• v.47 no.12
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• pp.852-859
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• 2009

The manufacturing process of zirconium alloys is an import factor to increase their strength and corrosion resistance. In order to find an improved manufacturing process of zirconium alloys in both Zr-1Nb-1Sn-0.1Fe (Alloy-A) and Zr-1.5Nb-0.4Sn-0.2Fe-0.1Cr (HANA-4) for fuel guide tubes, sheet samples were prepared by applying two- and three-step processes that were controlled by an annealing and reduction condition. The mechanical strength and corrosion resistance of both alloys were increased by applying the twostep process rather than the three-step process. From a matrix analysis using TEM, the property improvement is related to the decrease of the precipitate mean diameter with an application of the two-step process. In a comparison of the strength and corrosion properties between Alloy-A and HANA-4, the performance of HANA-4 was feasible for application to fuel guide tubes.

• The Korea Journal of Herbology
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• v.38 no.5
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• pp.31-37
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• 2023

Objective : This study was conducted to investigate the muscle-improving and therapeutic effects of Boehmeria platanifolia (BP) in a mouse model of dexamethasone-induced muscle atrophy. Methods : Muscle atrophy was induced in C57BL/6 mice by intraperitoneal administration of dexamethasone for 12 days. BP extract was administered orally at doses of 100 mg/kg and 200 mg/kg for 19 days, starting 7 days before the intraperitoneal administration of dexamethasone. Mice were weighed during the experimental period, and muscle strength and muscle weight were measured at the end of the experiment. The gastrocnemius (GASTROC) muscles of mice were isolated and the cross-sectional area (CSA) of the muscle fibers was measured after H&E staining. Results : Dexamethasone-induced muscle atrophy mice had a decrease in body weight compared to normal mice, and BP-administrated mice did not show significant change in body weight compared with a control group. Muscle strength in mice with induced muscle atrophy was reduced compared to normal and significantly increased with BP administration and positive control. In addition, the weight of the quadriceps (QUAD) muscle and fiber size of the GASTROC muscle, which was reduced in sarcopenia-induced mice, was increased by BP. Conclusion : BP extract increased muscle strength, muscle weight, and muscle fiber size in dexamethasone-induced muscle atrophy mice. This suggests that the efficacy of BP extracts in improving muscle strength and preventing and treating sarcopenia may be beneficial for the development of potential therapeutic or functional products.

• Advances in concrete construction
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• v.13 no.2
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• pp.163-181
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• 2022

To study the mechanical properties of steel reinforced recycled concrete (SRRC) filled circular steel tube columns under eccentric compression loads, this study presents a finite element model which can simulate the eccentrically compressed columns using ABAQUS software. The analytical model was established by selecting the reasonable nonlinear analysis theory and the constitutive relationship of materials in the columns. The influences of design parameters on the eccentric compressive performance of columns were also considered in detail, such as the diameter-thickness ratio of circular steel tube, replacement percentage of recycled coarse aggregate (RCA), slenderness ratio, eccentricity, recycled aggregate concrete (RAC) strength and steel strength and so on. The deformation diagram, stress nephogram and load-displacement curves of the eccentrically compressed columns were obtained and compared with the test results of specimens. The results show that although there is a certain error between the calculation results and the test results, the error is small, which shows the rationality on the numerical model of eccentrically compressed columns. The failure of the columns is mainly due to the symmetrical bending of the columns towards the middle compression zone, which is a typical compression bending failure. The eccentric bearing capacity and deformation capacity of columns increase with the increase of the strength of steel tube and profile steel respectively. Compared with profile steel, the strength of steel tube has a greater influence on the eccentric compressive performance of columns. Improving the strength of RAC is beneficial to the eccentric bearing capacity of columns. In addition, the eccentric bearing capacity and deformation capacity of columns decrease with the increase of replacement percentage of RCA. The section form of profile steel has little influence on the eccentric compression performance of columns. On this basis, the calculation formulas on the nominal eccentric bearing capacity of columns were also put forward and the results calculated by the proposed formulas are in good agreement with the test values.

• The Journal of Engineering Geology
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• v.34 no.1
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• pp.67-105
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• 2024

This study compares the quartzites of four quartzite units: The Fagfog Quartzite, Dunga Quartzite (member of the Robang Formation), Pandrang Quartzite (member of the Kalitar Formation) and the Chisapani Quartzite. The analysis shows variations in flakiness and elongation, as the Fagfog Quartzite displays low flakiness whereas the Pandrang and the Chisapani have moderate and the Dunga Quartzite has shown variations. The density values of the four quartzite units remain consistent, indicating uniform physical properties and porosity levels. However, bulk density values differ among the quartzites, suggesting variations in particle arrangement, porosity, and density. Regarding strength measures, the Pandrang and the Chisapani Quartzite have higher strength characteristics as compared to the Fagfog and the Dunga Quartzites. The Pandrang Quartzite has the highest average point load strength index, classifying it as "Extremely Strong". The resistance to impact and crushing forces varies among the quartzites, with lower Aggregate Impact Value (AIV) and Aggregate Crushing Value (ACV) indicating higher strength and durability. Durability tests show that the Fagfog Quartzite has high durability against slaking, with a slight decrease observed after the fifth cycle. The Dunga Quartzite shows varying degrees of weathering, while the Pandrang and the Chisapani Quartzite have minimal weight changes, indicating strong resistance to weathering. Magnesium sulfate soundness tests indicate high durability and resistance to degradation for all four units. The Los Angeles abrasion value (LAAV) tests indicate favorable resistance to abrasion for the majority of the Fagfog, Dunga, and the Pandrang Quartzites samples, while Chisapani Quartzite shows more variability in LAAV values. The Pandrang Quartzite shows a higher proportion of elongated particles but lower flakiness index values as compared to Fagfog and Dunga Quartzites while Chisapani Quartzite stands out with a significantly higher presence of flaky particles and lower elongation index values. Mechanically, the Fagfog and Dunga Quartzite show higher strength and better resistance to abrasion and freeze and thaw. The Pandrang Quartzite shows moderate resistance to crushing and sudden effect, while the Chisapani Quartzite has variable resistance to effect. This comparative study emphasizes the diversity and complexity of quartzite rock types, showing the need for comprehensive characterization and assessment to determine their suitability for specific applications.