• BMB Reports
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• v.44 no.1
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• pp.1-10
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• 2011

Inter-cellular communication via diffusible small molecules is a defining character not only of multicellular forms of life but also of single-celled organisms. A large number of bacterial genes are regulated by the change of chemical milieu mediated by the local population density of its own species or others. The cell density-dependent "autoinducer" molecules regulate the expression of those genes involved in genetic competence, biofilm formation and persistence, virulence, sporulation, bioluminescence, antibiotic production, and many others. Recent innovations in recombinant DNA technology and micro-/nano-fluidics systems render the genetic circuitry responsible for cell-to-cell communication feasible to and malleable via synthetic biological approaches. Here we review the current understanding of the molecular biology of bacterial intercellular communication and the novel experimental protocols and platforms used to investigate this phenomenon. A particular emphasis is given to the genetic regulatory circuits that provide the standard building blocks which constitute the syntax of the biochemical communication network. Thus, this review gives focus to the engineering principles necessary for rewiring bacterial chemo-communication for various applications, ranging from population-level gene expression control to the study of host-pathogen interactions.

• Journal of Microbiology and Biotechnology
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• v.33 no.4
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• pp.552-558
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• 2023

Levulinic acid (LA) is a valuable chemical used in fuel additives, fragrances, and polymers. In this study, we proposed possible biosynthetic pathways for LA production from lignin and poly(ethylene terephthalate). We also created a genetically encoded biosensor responsive to LA, which can be used for screening and evolving the LA biosynthesis pathway genes, by employing an LvaR transcriptional regulator of Pseudomonas putida KT2440 to express a fluorescent reporter gene. The LvaR regulator senses LA as a cognate ligand. The LA biosensor was first examined in an Escherichia coli strain and was found to be non-functional. When the host of the LA biosensor was switched from E. coli to P. putida KT2440, the LA biosensor showed a linear correlation between fluorescence intensity and LA concentration in the range of 0.156-10 mM LA. In addition, we determined that 0.156 mM LA was the limit of LA detection in P. putida KT2440 harboring an LA-responsive biosensor. The maximal fluorescence increase was 12.3-fold in the presence of 10 mM LA compared to that in the absence of LA. The individual cell responses to LA concentrations reflected the population-averaged responses, which enabled high-throughput screening of enzymes and metabolic pathways involved in LA biosynthesis and sustainable production of LA in engineered microbes.

• Journal of the Korean Data and Information Science Society
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• v.15 no.1
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• pp.1-10
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• 2004

In the Korean Economically Active Population Survey(EAPS), the sample sizes for small areas are typically too small to provide reliable estimators because the EAPS has been designed to produce unemployment statistics for large areas such as Metropolitan Cities and Province. In this study, we consider the synthetic and composite estimators for the unemployment rate of small areas, and apply them to real data on Choongbook province which is from the Korean EAPS of December 2000. The mean square errors of these estimators were estimated by the Jackknife method, and the efficiencies of small area estimators were evaluated in terms of the relative standard errors and the relative root mean square errors. As a result, the composite estimator is much more efficient than other estimators and it turns out that the composite estimator can produce the reliable estimates of the unemployment rate of small areas under the current EAPS system.

• Korean Journal of Soil Science and Fertilizer
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• v.49 no.1
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• pp.87-92
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• 2016

With the population growth and industrialization, the characteristics of discharged waste water and sewage have become more diverse. The removal of phosphorus (P) in the wastewater is essential for the prevention of eutrophication in the river and stream. This study was performed in order to estimate the field application of the Bacillus sp. 3434 BRRJ. Bacillus sp. 3434 BRRJ was cultured in the raw wastewater and synthetic medium at the 5 L reactor. The best optimum conditions for P removal by Bacillus sp. 3434BRRJ in the synthetic medium at the 5 L reactor were as follows: temperature, $30^{\circ}C$; P concentration, 20 mg/L; carbon sources, glucose + acetate (1:1); oxygen concentration, alternatively anaerobic and aerobic conditions. P removal efficiency under the optimum condition was 89.4%. In case of wastewater, P removal efficiency was 95.5% under controlled at $30^{\circ}C$. Through this study we confirmed that P removal by Bacillus sp. 3434BRRJ in case of wastewater was as effective as the synthetic medium. It is considered that Bacillus sp. 3434 BRRJ can be applied to the treatment of wastewater in order to biologically remove P from the wastewater on a large scale.

• Environmental Engineering Research
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• v.22 no.2
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• pp.141-148
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• 2017

Globalization, industrialization, mining, and uncontrolled population growth have fostered a shortage of potable water. Therefore, it has become imperative to understand an effective and reasonable water purification technique. A renewed interest in electrocoagulation (EC) has been spurred by the search for reliable, cost-effective, water-treatment processes. This paper has elucidated a technical approach for getting rid of heavy metals and total suspended solids (TSS) from synthetic water using an aluminum electrode. The effect of operational parameters, such as current density, inter-electrode distance, operating time, and pH, were studied and evaluated for maximum efficiency. This study corroborates the correlation between current density and removal efficiency. Neutral pH and a low electrode gap have been found to aid the efficacy of the EC setup. The outcome indicates that a maximum TSS removal efficiency of 76.6% occurred at a current density of $5.3mA/cm^2$ during a contact time of 30 min. In the case of heavy metals remediation, 40 min of process time exhibited extremely reduced rates of 99%, 59.2%, and 82.1%, for Cu, Cr, and Zn, respectively. Moreover, kinetic study has also demonstrated that pollutants removal follows first-and second-order model with current density and EC time being dependent.

• Korea journal of population studies
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• v.6 no.1
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• pp.3-42
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• 1983

The purposes of this paper is to introduce a technique for construction of nuptiality tables using proportion single of synthetic cohorts between times at two consecutive censuses, and to observe patterns of change in marriage habit of Korean through the nuptiality tables for single population from 1925 to 1980. In this paper abridged gross and net nuptiality tables for single population of Korea have been constructed for the four quinquinial period: 1925-1930, 1955-1960, 1970-1975, and 1975-1980. Significant time trend has been observed in the nuptiality rates among the single population. The major findings observed in each table are as follows; (1)During 1925-1930, the rates are initially small, but increase rapidly until they reach a maximum at ages 25-29 for bachelors and 20-24 for spinsters, following which they are still in high level. (2)During 1955-1960, the age pattern of nuptiality begins to change; for female population, the rates increase rapidly in the same pattern as in l925-l930 untill they reach the highest level at ages 25-29, after which they gradually decline. During the period, however, there were an unprecedented high level of marriage rates for male population at a relatively later ages. (3)During 1970-1975, Korea had experienced a transition in marriage habits; at this times, nuptiality rates for both sexes showed the same pyramid shaped patterns as in western countries as age increases. The mean ages at marriage for both sexes also reached the highest level of 27.5 years for males and 24.1 years for females. (4)During 1975-1980, the age patterns of nuptiality showed almost the same patterns as in 1970-1975. In the later age group, however, age-specific marriage rates for both sexes greatly declined compared to the level of 1970-1975, while the rate in age group of 20-24 for male population greatly increased.

• Journal of Microbiology and Biotechnology
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• v.17 no.10
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• pp.1704-1707
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• 2007

Monitoring of the phage-host system of Microlunatus phosphovorus indigenous in activated sludge was attempted. A laboratory-scale activated sludge process was operated for 5 weeks with synthetic wastewater. The phage-host system population in the process was monitored by plaque assay and FISH methods at every 3 days. During the process operation, the phage-host system populations were more or less steady, except for 1 week in the middle of the operation. In that period, initially M. phosphovorus decreased significantly and its lytic bacteriophages increased, and then M. phosphovorus increased back to its original level while its lytic bacteriophages decreased. This observation suggests that lytic bacteriophages should be considered as one of the biological factors affecting the bacterial population dynamics in activated sludge processes.

• Journal of Surface Science and Engineering
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• v.57 no.4
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• pp.234-253
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• 2024

As the population ages, the importance of effective bone disease treatments is increasing, highlighting the role of bone grafts. Bone grafts are categorized into natural (autografts, allografts, xenografts) and synthetic (ceramics, polymers). Natural grafts have excellent regenerative abilities but pose biological risks, while synthetic grafts are biocompatible but less effective in regeneration. Various studies aim to enhance the safety and efficacy of bone grafts, significantly altering their surface properties. This review examines these studies and the resulting surface changes, aiming to guide future research and clinical applications.

• Korean journal of applied entomology
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• v.28 no.3
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• pp.146-153
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• 1989

These studies were conducted to investigate development of chemical resistance in two-spotted spider mite (Tetranychus urticae Koch) trough single selection for a given period of time with five acaricides including carbophenothion and ethion of organo-phosphate compound, dicofol of organo-chlorine compound, cyhexatin of organo-tin compound, biphenthrin of synthetic pyrethroid compound; and to examine cross-resistance among the acaricides to the selected populations. The development of chemical resistance of two-spotted spider mite was greatly varied under single selection of the each five acaricides. The carbophenothion- and the ethion-populations at the 22nd and the 24th selected generations showed 156- and 64.1-fold resistant levels, respectively, as compared with the susceptible population. However, the dicofol population at the 28th selected generation exhibited 39.7-fold resistant level, and the biphenthrin population at the 24th selected generation revealed 25.2-fold resistant level, while the cyhexatin population at the 20th selected generation showed 13-fold resistant level. The carbophenothion-selected population showed high cross-resistance to ethion, and low cross-resistance to dicofol and biphenthrin. The ethion-selected population revealed also high cross-resistance to carbophenothion. The dicofol-or the biphenthrin-selected populations, however, exhibited moderate cross-resistance to carbophenothion and ethion. Meantime, the cyhexatin-selected population showed high cross-resistance to ethion and carbophenothion.

• CELLMED
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• v.4 no.1
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• pp.1.1-1.13
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• 2014

Epilepsy has now become the most serious brain disorder. A number of synthetic antiepileptic drugs are available in practice, however their effectiveness does not grip true with the entire population suffering from epilepsy. Traditional systems of medicine are popular in developing countries and most of the population relies on traditional medicines for their primary health care need. Medicinal plants to be an important source of traditional medicines. Various plants are used for the treatment of epilepsy in traditional system of medicines and various plants are yet to be scientifically investigated. Phyto-constituents have been the basis of treatment of human diseases including epilepsy. Herbal products are extensively used for the treatment of many diseases worldwide and where allopathic fails or has severe side effects. Psycho neural drugs are also have very serious side effects like physical dependence, tolerance, deterioration of cognitive function and effect on respiratory, digestive and immune system. So the treatments through herbal medicines are widely used across the world due to their wide applicability and therapeutic efficacy with least side effects, which in turn has accelerated the research regarding natural therapy. In this review we have summarized some herbal anti-epileptics.