• Journal of Preventive Medicine and Public Health
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• v.35 no.1
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• pp.65-71
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• 2002

Objective : To estimate the status of HIV infection and AIDS incidence using a back-calculation model in Korea. Methods : Back-calculation is a method for estimating the past infection rate using AIDS incidence data. The method has been useful for obtaining short-term projections of AIDS incidence and estimating previous HIV prevalence. If the density of the incubation periods is known, together with the AIDS incidence, we can estimate historical HIV infections and forecast AIDS incidence in any time period up to time t. In this paper, we estimated the number of HIV infections and AIDS incidence according to the distribution of various incubation periods Results : The cumulative numbers of HIV infection from 1991 to 1996 were $708{\sim}1,426$ in Weibull distribution and $918{\sim}1,980$ in Gamma distribution. The projected AIDS incidence in 1997 was $16{\sim}25$ in Weibull distribution and $13{\sim}26$ in Gamma distribution. Conclusions : The estimated cumulative HIV infections from 1991 to 1996 were $1.4{\sim}4.0$ times more than notified cumulative HIV infections. Additionally, the projected AIDS incidence in 1997 was less than the notified AIDS cases. The reason for this underestimation derives from the very low level of HIV prevalence in Korea, further research is required for the distribution of the incubation period of HIV infection in Korea, particularly for the effects of combination treatments.

• Restorative Dentistry and Endodontics
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• v.39 no.3
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• pp.149-154
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• 2014

Objectives: This study was performed to evaluate the cytotoxicity of four calcium silicate-based endodontic cements at different storage times after mixing. Materials and Methods: Capillary tubes were filled with Biodentine (Septodont), Calcium Enriched Mixture (CEM cement, BioniqueDent), Tech Biosealer Endo (Tech Biosealer) and ProRoot MTA (Dentsply Tulsa Dental). Empty tubes and tubes containing Dycal were used as negative and positive control groups respectively. Filled capillary tubes were kept in 0.2 mL microtubes and incubated at $37^{\circ}C$. Each material was divided into 3 groups for testing at intervals of 24 hr, 7 day and 28 day after mixing. Human monocytes were isolated from peripheral blood mononuclear cells and cocultered with 24 hr, 7 day and 28 day samples of different materials for 24 and 48 hr. Cell viability was evaluated using an MTT assay. Results: In all groups, the viability of monocytes significantly improved with increasing storage time regardless of the incubation time (p < 0.001). After 24 hr of incubation, there was no significant difference between the materials regarding monocyte viability. However, at 48 hr of incubation, ProRoot MTA and Biodentine were less cytotoxic than CEM cement and Biosealer (p < 0.01). Conclusions: Biodentine and ProRoot MTA had similar biocompatibility. Mixing ProRoot MTA with PBS in place of distilled water had no effect on its biocompatibility. Biosealer and CEM cement after 48 hr of incubation were significantly more cytotoxic to on monocyte cells compared to ProRoot MTA and Biodentine.

• Korean Journal of Soil Science and Fertilizer
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• v.30 no.1
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• pp.23-28
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• 1997

A better understanding of nitrogen transformations in soils is essential to increase fertilizer nitrogen use efficiency. A laboratory incubation study was conducted to determine net mineralization and nitrification in selected Piedmont soils. Net mineralization and nitrification increased up to 60 days in the surface layers of Enon, Mecklenburg and Chewacla. After 60 days both processes declined up to 90 days incubation. In Wehadkee, mineralization and nitrification did not differ with incubation time. In all subsurface layers, mineralization and nitrification increased with time up to 90 days. Mineralization and nitrification differed among soils in surface and subsurface layers. These differences might be influenced by soil type related to amount of mineralization, soil aeration and nitrifying bacterial populations. A mineralization and nitrification was greater in surface layers than in subsurface layers.

• Parasites, Hosts and Diseases
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• v.25 no.1
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• pp.24-36
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• 1987

The effect of praziquantel on P. westermani exposed in vitro was observed by stereomicroscope, light microscope and scanning electron microscope. Following results were found. 1. The worms incubated in $0.01{\;}{\mu}g/ml$ praziquantel were moving after 26-hour incubation. However, all of them were immobilized immediately after incubation in solutions over $0.01{\;}{\mu}g/ml$ concentration. 2. All of the exposed worms showed severe vacuolization not only in tegument but in subtegument, intestine, ovary, testis, Mehlis' gland and excretory bladder. 3. Vacuoles in tegument burst out to form craters. As incubation time went on, tegumental structure was disintegrated severely. The worms exposed to praziquantel were observed to be immobilized and be vacuolized of all tissues. Disintegration of reproductive organs suggests that praziquantel have suppressive effect on egg production when the flukes are not killed. The drug effects were found more related with incubation time than with drug concentration.

• The Korea Journal of Herbology
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• v.37 no.5
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• pp.53-61
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• 2022

Objectives : The aim of this study was to investigate the effect of Baicalein (BA) on the production of hydrogen peroxide in lipoteichoic acid-stimulated RAW 264.7 mouse macrophages. Methods : Lipoteichoic acid-stressed RAW 264.7 mouse macrophages were incubated with baicalein at concentrations of 50 and 100 µM. Incubation time is 30 minutes, 2 h, 12 h, and 18 h. After incubation, The production of hydrogen peroxide in RAW 264.7 mouse macrophages was measured with dihydrorhodamine 123 assay. Streptococcus aureus lipoteichoic acid and Streptococcus pyogenes lipoteichoic acid were used as cell-stimulating lipoteichoic acid. Cell viabilities were measured with a modified MTT assay. Berberine, indomethacin, and gallic acid were incubated for the same time as the comparative materials. Results : BA at the concentration of 50 and 100 µM did not show cytotoxicity on RAW 264.7 mouse macrophages for 24 h incubation. For 30 minutes, 2 h, 12 h, and 18 h incubation, BA at the concentration of 50 and 100 µM significantly inhibited the production of hydrogen peroxide in RAW 264.7 mouse macrophages stimulated by Streptococcus aureus lipoteichoic acid (p < 0.05); also, BA at the concentration of 50 and 100 µM also inhibited the productions of hydrogen peroxide in RAW 264.7 mouse macrophages stimulated by Streptococcus pyogenes lipoteichoic acid significantly (p < 0.05). Conclusions : BA might have anti-bacterial activity related to its inhibition of hydrogen peroxide production in lipoteichoic acid-stimulated RAW 264.7 mouse macrophages.

• KSBB Journal
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• v.24 no.6
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• pp.556-562
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• 2009

The biological treatment of TNT-containing wastewater, known commonly as pink water, was investigated using a stirred tank reactor with Stenotrophomonas maltophilia OK-5 bacterial culture. S. maltophilia OK-5 exhibited effective degradation of TNT contained in pink water, completely degrading TNT (100 mg/L) within 6 days of incubation. The dark-red brown color derived from Hydride-Meisenheimer complex became more pronounced during the incubation period, which was determined quantitatively. High-pressure liquid chromatography was used to measure residual TNT, which also resolved the metabolic intermediates (i.e., 2,4-dinitrotoluene, 2,6-dinitrotoluene and 2,4-dinitro-6-hydroxytoluene). Gas chromatography-mass spectrometry was used to verify these intermediates. Quantification of the nitroreductase (pnrB) gene isolated from S. maltophilia OK-5 growing in pink water was performed with real-time PCR. The amount of pnrB gene copies increased to $10^3$-fold after 5 days of incubation time.

• Asian-Australasian Journal of Animal Sciences
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• v.15 no.11
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• pp.1553-1558
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• 2002

This study was carried out to obtain informations regarding the effect of N-acetyl-D-glucosamine in the LEY (lactoseegg yolk) diluent according to incubation time in 5 ml maxi-straw and the effects of freezing rate, thawing temperature and thawing time in the LEN (lactose-egg yolk and N-acetyl-D-glucosamine) diluent on acrosome morphology and motility of frozen-thawed boar sperm. The study showed that the LEN diluent was higher post-thaw NAR (normal apical ridge) acrosome than the LEY diluent for 0.5 h incubation at 37$^{\circ}C$. However, there were no differences between the LEN and LEY diluents on post-thaw sperm motility according to incubation time. The straws frozen from 5.0 cm (20$^{\circ}C$/min) to 17.0 cm (1$^{\circ}C$/min) above the liquid nitrogen surface did not show any significant differences on post-thaw sperm motility. However, the straws frozen above 5.0 cm from the liquid nitrogen surface were higher NAR acrosome than those frozen above 17.0 cm. The post-thaw percentages of motile sperm and NAR acrosome were significantly higher (p<0.05) for the maxi-straws submerged for 40 or 45 sec in a 52$^{\circ}C$ water bath than for 30, 35, 50 or 55 sec. The mean sample temperatures of maxi-straws after 40 or 45 sec submersion were 20.7 or 26.4$^{\circ}C$. In conclusion, the sample temperature of the thawed semen was very important for post-thaw sperm survival in the LEN diluent of 5 ml maxi-straw. When the temperature of the thawed semen was 20.7$^{\circ}C$, the percentages of motile sperm and NAR acrosome were highest.

• Journal of Animal Reproduction and Biotechnology
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• v.37 no.4
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• pp.285-291
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• 2022

In 1951, Colin Russell Austin and Min Chueh Chang identified "capacitation", a special process involving ejaculated spermatozoa in the female reproductive tract. Capacitation is a phenomenon that occurs in vivo, but almost all knowledge of capacitation has been obtained from in vitro studies. Therefore, numerous trials have been performed to establish in vitro capacitation methods for various studies on reproduction. Although a series of studies have been conducted to develop an optimal protocol for inducing capacitation, most have focused on identifying the appropriate chemical compounds to induce the capacitation of boar spermatozoa in vitro. Therefore, the purpose of this study was to identify the optimal incubation time for inducing capacitation in vitro. Duroc semen was incubated for various periods (60, 90, and 120 min) to induce capacitation. Sperm function (sperm motility, motion kinematic parameters, and capacitation status) was evaluated. The results showed that total sperm motility, rapid sperm motility, progressive sperm motility, curvilinear velocity, and average path velocity significantly decreased in a time-dependent manner. However, the capacitation status did not show any significant changes. Taken together, these results indicate that an incubation time of more than 60 min suppresses sperm motility and motion kinematic parameters. Therefore, we suggest that 60 min may be the best incubation time to induce capacitation without negative effects on sperm motility and motion kinematics in boar spermatozoa in vitro.

• Asian-Australasian Journal of Animal Sciences
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• v.12 no.7
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• pp.1054-1062
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• 1999

The effects of dry roasting whole faba beans (WFB) and whole lupin seeds (WLS) at 110, 130 or $150{^{\circ}C}$ for 15, 30 or 45 min on rumen (RDCP%), estimated intestinal (IDCP%) and total tract disappearance of CP (TDCP%) and intestinal availability (IARUCP%) of rumen undegraded CP (RUCP%) were determined. The RDCP values were estimated by in sacco technique by incubating nylon bags for 8, 12 and 24 h in the rumen of dairy cows. The IDCP and IARUCP values were estimated using a sequence of ruminal incubation, in vitro incubation in acid-pepsin for 1 h and then in pancreatin for 24 h of three-step in vitro procedure technique. Dry roasting at 130 and $150^{\circ}C$ decreased RDCP with correspondingly increasing IDCP. The IDCP value generally increased from 12.3(raw) to 8.6, 14.8 and 39.6% (WFB) and from 28.3 (raw) to 33.7, 36.2 and 56.2% (WLS) at 8 h rumen incubation; from 2.9 (raw) to 2.9, 4.6 and 23.3% (WFB) and from 19.6 (raw) to 19.0, 24.0 and 46.6% (WLS) at 12 h rumen incubation; from 1.3 (raw) to 1.9, 1.7 and 11.0% (WFB) and from 4.4 (raw) to 4.2, 10.7 and 36.7% (WLS) at 12 h rumen incubation as the temperatures rose to 110, 130 and $150{^{\circ}C}$ respectively. The TDCP values were always high and increased by time in the rumen, the average values of which were 97.9, 96.6; 99.2, 96.9 and 99.6, 98.7% for WFB and WLS, respectively, at 8, 12 and 24 h rumen incubation. But within the same retention time, TDCP was generally unchanged. The average IARUCP increased from 87.3 (raw) to 87.4, 88.7 and 92.0% (WFB); from 87.6 (raw) to 88.9, 91.5 and 93.0% (WLS) at roasting temperatures of 110, 130 and $150{^{\circ}C}$, respectively. It was concluded that dry roasting can shift the digestion of CP from rumen to the lower gastrointestinal tract without depressing the digestion of RUCP. The best processing condition in this study was dry roasting at $150{^{\circ}C}$ for 45 min in terms of effects on the disappearances and availability of CP. Research data on intestinal availability of individual amino acids need to be further investigated.

• Asian-Australasian Journal of Animal Sciences
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• v.20 no.9
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• pp.1462-1467
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• 2007

This study investigated the effect of chemical treatments on tannins (condensed and hydrolysable) and on the trypsin inhibitor (TI) activity in salseed meal. Triplicate samples of ground salseed meal (1 kg) were mixed with 820 ml of either distilled water (pH 5.3), 0.67 M acetic acid (pH 2.4), 0.67 M sodium bicarbonate (pH 8.2) or 2% polyvinyl-pyrrolidone (PVP) solution. The material was placed in airtight plastic containers and incubated at $37^{\circ}C$ for 0, 3, 6, 12, 24, 48 and 72 h. Samples of untreated salseed meal which had not been subjected to soaking or incubation were run through the analysis to serve as control. Addition of water, acetic acid, sodium bicarbonate and PVP solutions to salseed meal and subsequent anaerobic incubation at $37^{\circ}C$ significantly reduced chemically detectable tannins. At each incubation time, alkali solution was more effective than its counterparts. The effect of acidic solution on hydrolysable tannin was least among the treatments. All the treatments reduced TI activity of salseed meal. The reduction in TI activity by these treatments was similar and ranged between 80-84%. Treatment time effected a decrease in the contents of antinutritional substances. However, the effect of the treatment with the reagents, even for zero incubation time, was quite pronounced. It may be concluded from the present results that the treatment of salseed meal with sodium bicarbonate (0.67 M) is more effective in reducing hydrolysable and condensed tannin contents than PVP, water and acid solutions. Treatment with sodium bicarbonate solution is more economical and easier to handle than acid and PVP treatments. Incubation of the treated material for 12 h is reasonably effective, economical and safe from any mould growth.