• Environmental Engineering Research
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• 제18권1호
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• pp.3-8
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• 2013

Collision cell technology-inductively coupled plasma-mass spectrometry (CCT-ICP-MS) was used to measure the concentrations of approximately 19 elements associated with airborne PM2.5 samples that were collected from a roadside sampling station in Daejeon, Korea. Standard reference material (SRM 2783, air particulate on filter media) of the National Institute of Standards and Technology was used for the quality assurance of CCT-ICP-MS. The elemental concentrations were compared statistically with the certified (or recommended) values. The patterns of distribution were clearly distinguished between elements with their concentrations ranging over four orders of magnitude. If compared in terms of enrichment factors, it was found that toxic trace elements (e.g., Sb, Se, Cd, As, Zn, Pb, and Cu) of anthropogenic origin are much more enriched in PM2.5 samples of the study site. To the contrary, the results of the correlation analysis showed that PM2.5 concentrations can exhibit more enhanced correlations with the elements (e.g., Fe, K, Si, and Ti) arising from earth's crust. The findings of strong correlations between PM2.5 and the elements of crustal origin may be directly comparable with the dominant role of those species by constituting a major fraction of even PM2.5 as well as PM10 at the roadside area.

• 정보교육학회논문지
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• 제5권2호
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• pp.197-206
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• 2001

고객관계관리 기술은 고객의 로열티 향상을 통해 이익 증대를 목적으로 한다. 현재 인터넷상의 교육용 사이트들은 구조화되지 못한 경우가 대부분이며, 아동 개개인에 대한 차별화된 서비스는 제공하지 못하고 있는 실정이다. 고객과 기업의 관계는 아동과 교육 사이트의 관계와 크게 다르지 않으므로 교육환경에서도 유용하게 이용될 수 있다. 본 논문에서는 CRM 이론에 대하여 알아보고, CRM 이론이 적용된 상업용 사이트와 널리 알려진 교육용 포탈사이트 및 학교 홈페이지를 분석하여 효율적인 학생관계관리를 위해서는 어떤 개인화된 서비스가 필요하며, 학교 홈페이지가 어떠한 형태로 설계되어져야 하는지에 대해 알아보았다. 그리고 회원가입, 관리자메뉴, 개인화설계, 학생에 대한 오퍼, 커뮤니케이션 측면에서 부분적으로 구현하였다.

• 한국축산식품학회지
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• 제41권2호
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• pp.335-342
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• 2021

Vitamin B12 deficiency may lead to serious health issues in both infants and adults. A simple analytical method involving sample pretreatment with enzyme, followed by cyanide addition under acidic conditions; separation on an immunoaffinity column; and high-performance liquid chromatography (HPLC) was developed for the rapid detection and quantitation of vitamin B12 in powdered milk. Detection limit and powdered milk recovery were determined by quantitative analysis. The limits of detection and quantitation were 2.71 and 8.21 ㎍/L, respectively. Relative standard deviations of the intra-day and inter-day precisions varied in the ranges of 0.98%-5.31% and 2.16%-3.90%, respectively. Recovery of the analysis varied in the range of 83.41%-106.57%, suggesting that the values were acceptable. Additionally, vitamin B12 content and recovery in SRM 1849a were 54.10 ㎍/kg and 112.24%, respectively. Our results suggested that the analytical method, including the sample pretreatment step, was valid. This analytical method can be implemented in many laboratory-scale experiments that seek to save time and labor. Therefore, this study shows that immunoaffinity-HPLC/ultraviolet is an acceptable technique for constructing a reliable database on vitamin B12 in powdered milk containing starch as well as protein and/or fat in high amounts.

• The Journal of Asian Finance, Economics and Business
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• 제9권9호
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• pp.317-325
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• 2022

The simple regression model (SRM) is used in this study to look at potential economic growth-influencing factors. The sample's period runs from 2005 to 2019. The data was gathered from various ministries and government agencies such as the Central Bank of Afghanistan's Statistical Bulletin, the World Bank, the United Nations (UN), World Bank open data, NASA, Ministry of Finance (MoF), Ministry of Economy (MoE), and Central Bank of Afghanistan's Statistical Bulletin (CBA), as well as the internet and news. There is an urgent need to ensure that taxes are collected in the most efficient manner possible because one of the enormous management gaps in Afghanistan over the last two decades has been tax evasion. According to the results of this study, tax evasion has a negative and significant impact on Afghanistan's economic growth. We can affirm that the subject of this article is among the most significant topics recently discussed in my country. If the right solutions are implemented, It can significantly contribute to quickening the cycle of the developing Afghan economy and turning it from an unstable to a sustainable one.

• 한국식품위생안전성학회지
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• 제35권6호
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• pp.535-543
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• 2020

유전적 조절, 유전자 발현 그리고 환경적 단서, 화학적 신호에 대응하는 표현형 변이에서 세포 RNA는 ubiquitous 역할 이외에도 세포 외 RNA(exRNA)라 하는 새로운 형태의 RNA는 추후 연구의 방향을 제시한다. exRNA는 membrane vesicles 또는 세포 외 소포체(EV)로 알려진 membrane blebs를 통해 세포 외부로 운반된다. EV의 형성은 원핵생물, 진핵생물, 고세균을 포함한 모든 미생물군에 우세하게 보존되어있다. 본 리뷰는 세균 유래 exRNA에 관해 세가지 주제에 초점을 두었다. exRNA의 발견과 박테리아 유전자 배열에 대한 외부 RNA의 영향, b. exRNA의 분비기작을 통한 방출, c. 다른 그람음성 및 그람양성균에 의해 분비되는 exRNA로 고안될 수 있는 응용 가능분야이다. 본 리뷰에서 장내 미생물군의 probiotics 및 후성유전학적 규제에서 본 exRNA와 exRNA마커와 같은 EV파생 응용프로그램에 대한 의견을 제공할 것이다.

• Bulletin of the Korean Chemical Society
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• 제31권7호
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• pp.1907-1914
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• 2010

A novel catalytic kinetic method is proposed for the determination of Se(IV), Se(VI) and total inorganic selenium in water based on the catalytic effect of Se(IV) on the reduction of bromate by p-nitrophenylhydrazine at pH 3.0. The generated bromine, $Br_2$ or $Cl_2$ plus $Br_2$ in 0.1 M NaCl (or NaBr) environment efficiently decolorized Calmagite and the reaction was monitored spectrophotometrically at 523 nm as a function of time. In this indicator reaction, bromide acted as an activator for the catalysis of selenium (IV) and a reducing agent for selenium (VI) at pH 3.0, which allowed the determination of total selenium. The fixed time method was adopted for the determination and speciation of inorganic selenium. Under the optimum conditions, the calibration graph are linear in the range 1 - 35 ${\mu}gL^{-1}$ of Se(IV) for the fixed time method at $25^{\circ}C$. The detection limit based on statistical $3S_{blank}$/m-criterion was 0.215 ${\mu}gL^{-1}$ for the fixed time method (7 min). All of the variables that affect the sensitivity at 523 nm were investigated, and the optimum conditions were established. The interference effect of various cations and anions on the Se (IV) determination was also studied. The selectivity of the selenium determination was greatly improved with the use of the strongly cation exchange resin such as Amberlite IR120 plus. The proposed kinetic method was validated statistically and through recovery studies in natural water samples. The RSDs for ten replicate measurements of 5, 15 and 25 ${\mu}gL^{-1}$ of Se(IV) and Se(VI) was changed between 2.1 - 4.85%. Analyses of a certified standard reference material (NIST SRM 1643e) for selenium using the fixed-time method showed that the proposed kinetic method has good accuracy. Se(IV), Se(VI) and total inorganic selenium in environmental water samples have been successfully determined by this method after selective reduction of Se(VI) to Se(IV).

• 미생물학회지
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• 제46권3호
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• pp.233-239
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• 2010

Bacillus subtilis에 존재하는 DEAD-box RNA helicase에 대한 유전자 상동성 검색을 통해 yqfR, yfmL, ydbR, deaD 의 4종류의 유전자를 확인하였고 이들 유전자 각각의 결손 돌연변이체를 제조하였다. 이들 돌연변이체들의 특성을 알아보기 위하여 LB 배양액을 사용하여 여러 온도에서의 생장 속도를 조사하였다. LB 배양액에서 $37^{\circ}C$의 생장 결과 ydbR 결손 균주가 다소 생장이 느려지나($T_d$=53 min) 다른(yqfR, yfmL, deaD) 결손 돌연변이체들은($T_d$=30-40 min) 결손이 없는 야생형 균주 CU1065와($T_d$=32 min) 유사하였다. 반면에 $22^{\circ}C$에서의 생장은 CU1065 ($T_d$=102 min)에 비해 yqfR ($T_d$=151 min), yfmL ($T_d$=214 min), ydbR ($T_d$=343 min) 결손 균주 순으로 생장속도가 느린 저온 민감성을 보인다. deaD의 $22^{\circ}C$에서의 생장 속도는 ($T_d$=109 min) CU1065와 ($T_d$=102 min) 매우 유사하여 저온 민감성을 보이지 않았다. 그리고 이들 유전자들의 이중, 삼중, 사중의 결손 균주들을 제조하였고, 여러 온도에서 ($42^{\circ}C$, $37^{\circ}C$, $22^{\circ}C$) LB 배양액을 사용하여 생장 속도를 측정 하였다. 다중 결손은 단일 결손보다 더 심한 저온 민감성을 보이며, 이중 결손의 경우, ydbR과 yfmL의 결손이 다른 조합의 결손보다 보다 큰 저온 민감성을 나타내었다 ($T_d$=984 min). 이러한 저온 민감성은 E. coli의 csdA 혹은 srmB 결손의 결과와 유사하며 리보솜 조립과 관련이 있는 생리적 기능으로 보인다.

• Asian-Australasian Journal of Animal Sciences
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• 제16권8호
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• pp.1108-1117
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• 2003

In Guadeloupe small ruminants (SR) are reared for meat production under pasture conditions. Intensive rotational grazing systems (irrigated, fertilised and high stocked) allow reasonable levels of production but generate high post-grazing residues. Experiments were designed to control them. A system in which residuals were mown (RM) was tested in comparison to the control system (Residuals Remained, RR). The same design was carried out for two years with Creole goat (G) and Martinik sheep (S). An accelerated reproductive rate (3 parturitions over 2 years) was carried out. Systems were compared at three parturition seasons per year(dry, intermediate and rainy seasons). Each group was composed of 20 goats ($36.0{\pm}2.5kg$) or 20 ewes ($46.8{\pm}2.4kg$). The female body traits did not vary according to pasture management and seasons. The stocking rate averaged 1,400 kg LW/ha. The mean fertility rate for does varied significantly (p<0.05) within the kidding season, from $80.4{\pm}0.5%$ to $93.7{\pm}2.9%$ while the mean litter size was $2.30{\pm}0.07$ total kids born. No effect of pasture system was observed. Corresponding values for ewes were $83.2{\pm}12.8%$ vs. $75.6{\pm}12.5%$ (p<0.05) and $2.43{\pm}0.24$ vs. $2.03{\pm}0.29$ (p<0.01) total lambs born for SRM and SRR ewes, respectively. A seasonal effect was observed upon ewe performances. The preweaning mortality of kids and lambs averaged 16.3% and 14.4%, respectively. It was 7 and 9 percentage points more (p<0.01) for RR than for RM kids and lambs, respectively. For both species, weaning took place at an average age of $81.4{\pm}3.6days$. In Creole kids, live weight at birth and at weaning were $1.9{\pm}0.2kg$ and $8.9{\pm}0.8kg$, respectively. In the Martinik sheep, the traits averaged $2.9{\pm}0.2kg$ and $18.9{\pm}0.9kg$. For both traits in both species, significant (p<0.05) group${\times}$season interactions were recorded. The consequences of elimination of post-grazing residues varied according to the SR species, the environmental conditions and the animal physiological status. The forage characteristics were not limiting factors since forage availability in the RM systems (2,300 and 2,600 kg DM/ha, respectively) and chemical composition were at satisfactory levels (CP content averaged 12 and 10%). It is recommended to develop new grazing system which would allow the use of post-grazing residues instead of mowing the refusals.