• Korean Journal of Pharmacognosy
• /
• v.38 no.1
• /
• pp.84-89
• /
• 2007

The present study describes the preliminary evaluation of the antioxidant activities and the neuroprotective effect of methanolic extracts from Psoralea corylifolia Linne (PCE). The antioxidant activities and neuroprotective effect of the PCE were evaluated by total phenolic contents (TPC), DPPH radical scavenging activity (RSA), reducing power (RP), MTT reduction assay, and LDH release assay. TPC, DPPH RSA, and RP of the extract at concentration of 100 ${\mu}g$ was 125.93 ${\mu}g$, 63.81%, 0.138, respectively, and those were concentration dependent. The treatment of PC12 and N18-RE-105 cells with various PCE concentrations under $H_2O_2$ resulted in the induction of protective effect in a dose-dependent manner, as determined by the results of an MTT reduction assay and LDH release assay. Therefore, these results suggest that PCE could be a new potential candidate as an antioxidant against neuronal diseases.

• The Korea Journal of Herbology
• /
• v.23 no.4
• /
• pp.171-177
• /
• 2008

Objectives: This study presents a reversed-phase high-performance liquid chromatography- pulsed amperometric detection(RP-HPLC-PAD) method for the determination of puerarin and daidzin in Puerariae Radix extract and Chinese medicinal preparations. Methods: Chromatographic separation was performed using a 10% acetonitrile with a reversed-phase column(Unison UK-C18, $100mm{\times}2.0mm$ I.D.; $3{\mu}m$). The analyses were detected by pulsed amperometric detector(PAD) in alkaline conditions by combining with post-column NaOH solution. Geniposide was used as an internal standard. Results: The limit of detection(S/N=3) and the limit of quantification(S/N=10) were 0.025 ng, 0.075 ng for puerarin, and 0.05 ng, 0.15 ng for daidzin, respectively. The intra- and inter-day precisions(RSDs) were less than 6.5% and average recoveries of puerarin were 99.7-101.3% and those of daidzin were 101.0-102.8%. Conclusions: According to above results, we developed a determination method for puerarin and daidzin in Puerariae Radix with high sensitivity and selectivitely.

• The Korean Journal of Physiology and Pharmacology
• /
• v.17 no.3
• /
• pp.229-235
• /
• 2013

Among several animal models of retinitis pigmentosa (RP), the more recently developed rd10 mouse with later onset and slower rate of retinal degeneration than rd1 mouse is a more suitable model for testing therapeutic modalities. We therefore investigated the time course of retinal degeneration in rd10 mice before adopting this model in our interventional studies. Electroretinogram (ERG) recordings were carried out in postnatal weeks (PW) 3~5 rd10 (n=23) and wild-type (wt) mice (n=26). We compared the amplitude and implicit time of the b-wave of ERG records from wt and rd10 mice. Our results showed that b-wave amplitudes in rd10 mice were significantly lower and the implicit time of b-waves in rd10 mice were also significantly slower than that in wt mice ($20{\sim}160{\mu}V$ vs. $350{\sim}480{\mu}V$; 55~75 ms vs. 100~150 ms: p<0.001) through PW3 to PW5. The most drastic changes in ERG amplitudes and latencies were observed during PW3 to PW4. In multichannel recording of rd10 retina in PW2 to PW4.5, we found no significant difference in mean spike frequency, but the frequency of power spectral peak of local field potential at PW3 and PW3.5 is significantly different among other age groups (p<0.05). Histologic examination of rd10 retinae showed significant decrease in thickness of the outer nuclear layer at PW3. TUNEL positive cells were most frequently observed at PW3. From these data, we confirm that in the rd10 mouse, the most precipitous retinal degeneration occurs between PW3~PW4 and that photoreceptor degeneration is complete by PW5.

• Polymer(Korea)
• /
• v.28 no.4
• /
• pp.305-313
• /
• 2004

A vacuum pressure-difference technique for making a nano-precision replica is investigated for various applications. Master patterns for replication were fabricated using a nano-replication printing (nRP) process. In the nRP process, any picture and pattern can be replicated from a bitmap figure file in the range of several micrometers with resolution of 200nm. A liquid-state monomer is solidified by two-photon absorption (TPA) induced by a femto-second laser according to a voxel matrix scanning. After polymerization, the remaining monomers were removed simply by using ethanol droplets. And then, a gold metal layer of about 30nm thickness was deposited on the fabricated master patterns prior to polydimethylsiloxane molding for preventing bonding between the master and the polydimethylsiloxane mold. A few gold particles attached on the polydimethylsiloxane stamp during detaching process were removed by a gold selecting etchant. After fabricating the polydimethylsiloxane mold, a nano-precision polydimethylsiloxane replica was reproduced. More precise replica was produced by the vacuum pressure-difference technique that is proposed in this paper. Through this study, direct patterning on a glass plate, replicating a polydimethylsiloxane mold, and reproducing polydimethylsiloxane replica are demonstrated with a vacuum pressure-difference technique for various micro/nano-applications.

• Clinical and Experimental Pediatrics
• /
• v.64 no.12
• /
• pp.652-660
• /
• 2021

Background: Viral load and shedding duration are highly associated with the transmission of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection. However, limited studies have reported on viral load or shedding in children and adolescents infected with sudden acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Purpose: This study aimed to investigate the natural course of viral load in asymptomatic or mild pediatric cases. Methods: Thirty-one children (<18 years) with confirmed SARS-CoV-2 infection were hospitalized and enrolled in this study. Viral loads were evaluated in nasopharyngeal swab samples using real-time reverse transcription polymerase chain reaction (E, RdRp, N genes). cycle threshold (Ct) values were measured when patients met the clinical criteria to be released from quarantine. Results: The mean age of the patients was 9.8 years, 18 (58%) had mild disease, and 13 (42%) were asymptomatic. Most children were infected by adult family members, most commonly by their mothers. The most common symptoms were fever and sputum (26%), followed by cough and runny nose. Nine patients (29%) had a high or intermediate viral load (Ct value≤30) when they had no clinical symptoms. Viral load showed no difference between symptomatic and asymptomatic patients. Viral rebounds were found in 15 cases (48%), which contributed to prolonged viral detection. The mean duration of viral detection was 25.6 days. Viral loads were significantly lower in patients with viral rebounds than in those with no rebound (E, P=0.003; RdRp, P=0.01; N, P=0.02). Conclusion: Our study showed that many pediatric patients with coronavirus disease 2019 (COVID-19) experienced viral rebound and showed viral detection for more than 3 weeks. Further studies are needed to investigate the relationship between viral rebound and infectiousness in COVID-19.

• Asian Pacific Journal of Cancer Prevention
• /
• v.15 no.24
• /
• pp.10729-10733
• /
• 2015

Background: Adjuvant androgen deprivation therapy (ADT) is a treatment option for prostate cancer (PC) patients after radical prostatectomy (RP). Although it can achieve a good progression-free survival rate, some patients still develop clinical metastasis. We here investigated risk factors of clinical metastasis in post-prostatectomy patients who received immediate adjuvant ADT. Materials and Methods: We identified 197 patients with non-metastatic PC who underwent RP at our institution between 2000 and 2012, followed by adjuvant ADT. The associations of various clinicopathologic factors with clinical metastasis (primary endpoint) and cancer-specific survival (secondary endpoint) were assessed. Multivariate analysis was conducted using a Cox proportional hazards model. Median follow-up was 87 months after RP. Results: Nine (4.6%) patients developed clinical metastasis and six (3.0%) died from PC. Eight of nine metastatic patients had a pathologic Gleason score (GS) 9 and developed bone metastasis, while the remaining one had pathologic GS 7 and developed metastasis only to para-aortic lymph nodes. On multivariate analyses, pathologic GS ${\geq}9$ and regional lymph node metastasis (pN1) were independent predictors of clinical metastasis and pathologic GS ${\geq}9$ was an independent predictor of cancer-specific death. Conclusions: Pathologic GS ${\geq}9$ and pN1 were independent predictors of clinical metastasis in post-prostatectomy patients who received immediate adjuvant ADT. Furthermore, pathologic GS ${\geq}9$ was an indispensable condition for bone metastasis, which may imply that patients with GS ${\leq}8$ on adjuvant ADT are unlikely to develop bone metastasis.

• Korean Journal of Soil Science and Fertilizer
• /
• v.38 no.6
• /
• pp.313-320
• /
• 2005

Various by-product composts are applied in alpine farmland, and some of them generate many problems especially when they are not completely composted. The objective of this study was to investigate the physicochemical and spectroscopic properties of by-product composts used in Gangweon alpine uplands. Average organic matter content, C/N ratio and NaCl content in 3 species of registered composts were 33%, 13 and 0.8%, respectively, and the general quality were better than the guideline of by-product compost. Odor and contents of $NH_3$ and $CO_2$ in the registered composts were relatively lower than those in the unregistered composts. Among the 13 unregistered composts tested in this experiment, 3 species contained organic matter content less than 25%, 5 species had C/N ratio less than 10, and 8 species contained NaCl exceeded the acceptable level. Eight species in the unregistered composts contained more than 50% of water. Contents of heavy metals in both the registered and unregistered composts were lower than the acceptable level. In spectroscopic property analysis, registered composts were Band P types, and unregistered composts were Rp and P types.

• Ocean and Polar Research
• /
• v.36 no.3
• /
• pp.247-254
• /
• 2014

In our continuing study on the antioxidant activity of Polysiphonia stricta, its crude extract was fractionated into n-hexane, 85% aqueous methanol (85% aq.MeOH), n-butanol (n-BuOH), and water fractions according to solvent polarity. The solvent fractions were evaluated for their potential to inhibit lipid peroxidation and reactive oxygen species (ROS) production in HT 1080 cells. The n-BuOH fraction most strongly inhibited both lipid peroxidation and ROS production in HT 1080 cells. The n-BuOH fraction was further separated by repeated silica gel column chromatography and RP-HPLC to give methyl aconitates (2 and 3). The chemical structure of isolated compounds was determinated by NMR spectral analysis.

• Industrial Engineering and Management Systems
• /
• v.1 no.1
• /
• pp.87-92
• /
• 2002

A stochastic process {$A_n$, n = 1, 2, ...} is an arithmetic process (AP) if there exists some real number, d, so that {$A_n$ + (n-1)d, n =1, 2, ...} is a renewal process (RP). AP is a stochastically monotonic process and can be used for modeling a point process, i.e. point events occurring in a haphazard way in time (or space), especially with a trend. For example, the vents may be failures arising from a deteriorating machine; and such a series of failures id distributed haphazardly along a time continuum. In this paper, we discuss estimation procedures for an AP, similar to those for a geometric process (GP) proposed by Lam (1992). Two statistics are suggested for testing whether a given process is an AP. If this is so, we can estimate the parameters d, ${\mu}_{A1}$ and ${\sigma}^{2}_{A1}$ of the AP based on the techniques of simple linear regression, where ${\mu}_{A1}$ and ${\sigma}^2_{A1}$ are the mean and variance of the first random variable $A_1$ respectively. In this paper, the procedures are, for the most part, discussed in reliability terminology. Of course, the methods are valid in any area of application, in which case they should be interpreted accordingly.

• Journal of Ocean Engineering and Technology
• /
• v.20 no.5 s.72
• /
• pp.82-88
• /
• 2006

This assessment is concerned with the fatigue strength of the tendon porch found in TLP. Lorge-scale fatigue tests with models constructed at 30% the size of the real structures have been carried out to investigate the fatigue behavior of the API 2W Grade 50 steel recently produced by POSCO. The fatigue life for the present test models was obtained based on the concept of nominal stress. A comparison of the present test results with those obtained by a numerical approach based on the structural analysis results has showngood agreement. The present results were also compared with the design curves in DnV RP-C203.