• 한국식품과학회지
• /
• 제33권5호
• /
• pp.582-588
• /
• 2001

단체급식용으로 납품되는 생계육에서 Salmonella를 분리하여 생육제어를 위한 생리특성을 분석하였다. 계육의 총균수는 표피의 내부 살부위에서도 표피 균수의 약 10%정도가 검출되었으며 75 개 계육시료로부터 선택배지를 사용하여 분리한 후 최종적으로 51 주의 Salmonella를 동정하였다. 이들 균주 중 약 70%의 Salmonella는 4종 이상의 항생제에 내성을 보이는 다제내성균으로 보여 국내에서의 기 분리균에 비해서 높은 비율의 항생제에 대한 내성을 나타내었다. 이들 Salmonella에 대한 여러 가지 위생처리제인 유기산의 중 lactic acid와 trisodium phosphate를 agar disk diffusion으로 표준균주인 S. typhimurium ATCC 14028, S. typhimurium ATCC 12023, S. heidelberg and S. enteritidis(isolated from egg)와 비교하였다. Lactic acid는 분리된 Salmonella나 표준균주 모두 비슷한 정도의 내성을 보여 주었고 오히려 분리 Salmonella는 더 내성이 적었다. 그러나 최근에 중요시되는 trisodium phosphate에는 표준균주에 비하여 분리된 wild type에서 내성이 강한 균주가 거의 절반에 가까운 정도로 많음을 알 수가 있었다. 또한 trisodium phosphate에 대한 내성은 처리시간과 처리 후 재생배지에 따라 다르게 보여서 이들은 환경에 따 라 내성이 다르게 나타난다는 것을 알았다. 계육에 오염된 Salmonella는 wild type이므로 실제 위생처리제로 사용할 때는 좀더 철저한 처리가 요망되었다. 그러므로 집단 급식소에 납품되는 계육은 브로일러 사육단계에서의 항생제 관리와 도계과정으로부터 세균오염을 줄여야 하는 노력과 함께 이러한 식중독균의 제어를 위한 위생처리제에 대한 지속적인 기술개발도 필요할 것이다.

• Journal of the Korean Wood Science and Technology
• /
• 제51권1호
• /
• pp.49-57
• /
• 2023

This research aimed to evaluate the durability of Samama (Anthocephalus macrophyllus) wood treated with boron preservatives, citric acid (CA), and heating against termites. Wood samples were impregnated firstly with 5% boron solutions, such as boric acid, borax and boric acid + borax combination at 1:1 (w/w). The second impregnation used 5% CA. The impregnations were conducted in a pressure tank at 7 kg/cm² for 4 hours. After impregnation, the samples were heat treated at 80℃ or 160℃. All the treated and control samples were exposed to decay fungi, drywood termites and subterranean termites based on SNI 7207:2014 standard. The results showed that boron preservatives reduced fungal attacks on Samama wood. The combination treatment of boric acid, CA and heat treatment at 160℃ was also effective to increase the resistance of Samama wood against white- and brown rot fungi, and drywood termites. Heat treatment consistently improved the resistance of Samama wood from decay fungi.

• 한국표면공학회지
• /
• 제57권1호
• /
• pp.8-13
• /
• 2024

Anodizing of Al6061 alloy was conducted in two different electrolytes of 20% sulfuric acid and 8% sulfuric acid + 3 % oxalic acid solutions at a constant current or decreasing current density conditions, and its dielectric breakdown voltage was measured. The surface morphology of anodic oxide films was observed by TEM and thermal treatment was carried out at 400 ℃ for 2 h to evaluate the resistance of the anodic oxide films to crack initiation. The anodic oxide film formed in 8% sulfuric acid + 3 % oxalic acid solution showed higher dielectric breakdown voltage and better resistance to crack initiation at 400 ℃ than that formed in 20% sulfuric acid solution. The dielectric breakdown voltage increased 6 ~12% by applying decreasing current density comparing with a constant current density.

• 약학회지
• /
• 제43권6호
• /
• pp.789-792
• /
• 1999

The complete nucleotide sequence of pKH4, a small multidrug resistance (smr) plasmid isolated from multidrug resistant Staphylococcus aureus SA5, was determined. Sequence analysis has revealed that pKH4 has two open reading frames for Rep and Smr proteins. The comparison of the amino acid sequence of Smr protein of pKH4 with those of other Smr proteins of various Staphylococcus showed that Smr protein of pKH4 is a new member of the SMR family.

• Journal of the Korean Wood Science and Technology
• /
• 제26권3호
• /
• pp.33-40
• /
• 1998

The phenolic acids in needles of five pine species such as Pinus densiflora, P. thunbergii. P. virginiana. P. rigida. and P. koraiensis were analyzed seasionally (March, June, September and December) in order to investigate the resistant factors against pine gall-midge(Thecodiplosis japonensis Uchida et Inouye). The interrelation of resistance to pine gall-midge and the content of phenolic acids in pine needles was investigated in the artificial hybride pine species. The contents of salicylic acid in susceptible species (P. densiflora and P. thunbergii) to pine gall-midge which watered with salicylic acid solution in a pot was determined. The results can be concluded as follows, 1. There was a little change in total phenolic constituents of resistant and susceptible pines seasonally. The each content of benzoic acid, salicylic acid and p-hydroxybenzoic acid in June was the highest through four seasons. 2. In June, resistant species showed higher content of salicylic acid than susceptible species, while the content of gallic acid was the highest in December. 3. Among the 21 artificial hybrids(P. densiflora ${\times}$ P. virginiana. P. thunbergii ${\times}$ P. virginiana), the hybrides of the higher salicylic acid content showed the lower rate of pine gall formation. 4. Pine gall formation of the susceptible species which were watered with salicylic acid solution remarkably decreased.

• 한국표면공학회:학술대회논문집
• /
• 한국표면공학회 2016년도 추계학술대회 논문집
• /
• pp.153-153
• /
• 2016

Aluminum alloys have poor corrosion resistance compared to the pure aluminum due to the additive elements. Thus, anodizing technology artificially generating thick oxide films are widely applied nowadays in order to improve corrosion resistance. Anodizing is one of the surface modification techniques, which is commercially applicable to a large surface at a low price. However, most studies up to now have focused on its commercialization with hardly any research on the assessment and improvement of the physical characteristics of the anodized films. Therefore, this study aims to select the optimum temperature of sulfuric electrolyte to perform excellent corrosion resistance in the harsh marine environment through electrochemical experiment in the sea water upon generating porous films by variating the temperatures of sulfuric electrolyte. To fabricate uniform porous film of 5083 aluminum alloy, we conducted electro-polishing under the 25 V at $5^{\circ}C$ condition for three minutes using mixed solution of ethanol (95 %) and perchloric (70 %) acid with volume ratio of 4:1. Afterward, the first step surface modification was performed using sulfuric acid as an electrolyte where the electrolyte concentration was maintained at 10 vol.% by using a jacketed beaker. For anode, 5083 aluminum alloy with thickness of 5 mm and size of $2cm{\times}2cm$ was used, while platinum electrode was used for cathode. The distance between the two was maintained at 3 cm. Afterward, the irregular oxide film that was created in the first step surface modification was removed. For the second step surface modification process (identical to the step 1), etching was performed using mixture of chromic acid (1.8 wt.%) and phosphoric acid (6 wt.%) at $60^{\circ}C$ temperature for 30 minutes. Anodic polarization test was performed at scan rate of 2 mV/s up to +3.0 V vs open circuit potential in natural seawater. Surface morphology was compared using 3D analysis microscope to observe the damage behavior. As a result, the case of surface modification presented a significantly lower corrosion current density than that without modification, indicating excellent corrosion resistance.

• 한국결정성장학회지
• /
• 제26권3호
• /
• pp.101-108
• /
• 2016

동 제련 과정에서 발생되는 동 슬래그는 국내에서 년간 70만톤 이상이 발생되고 있어 산업부산물의 건설소재로서의 재활용에 대한 관심이 증가되고 있다. 이에 본 연구에서는 동 제련 슬래그의 3가지 유형의 입도형상과 잔골재로 사용된 강사의 대체 치환율 변화를 실험변수로 선정하여, 동 슬래그를 사용한 시멘트 모르타르의 강도 및 공극구조 특성, 황산 침지 저항성 등의 실험을 통해 건설용 골재로서의 사용가능성을 평가하고자 하였다. 실험결과 동 제련 슬래그 입도는 강도에 미치는 영향인자로 확인되었으며 동 제련 슬래그 잔골재 치환율 60 %인 경우가 가장 높은 강도를 보였다. 또한 잔골재를 동 제련 슬래그로 치환함으로 인해 기공크기가 감소되는 것으로 나타났으며, 황산에 대한 저항성도 증가되는 것으로 나타났다.

• 한국동물위생학회지
• /
• 제38권2호
• /
• pp.95-100
• /
• 2015

An investigation was carried out to determine the prevalence and antimicrobial resistance of Salmonella isolated from chicks and ducks. A total of 2,522 samples collected from 281 farms were examined from 2013 to 2014. The overall prevalence of Salmonella spp. was 21.7% (61/281) of farms and 83 isolates (3.3%) were isolated from 2,522 samples. Nine serotypes of Salmonella spp. were identified such as S. Typhimurium (19/83), S. Enteritidis (12/83), S. London (11/83), S. Senftenberg (8/83), S. Infantis (4/83), S. Montevideo (3/83), S. Hadar (3/83), S. Saintpaul (1/83), S. Rissen (1/83) and S. Arizonae (2/83). Nineteen isolates were found to be untypable serotypes. In the results of antimicrobial resistance test, all of isolates were resistant to at least two antimicrobial agent and the high resistance was found to nalidixic acid (66.3%), streptomycin (57.8%). All of isolates were susceptible to amoxacillin/clavulic acid, cefeprime, ampicillin, sulfamethoxazole/trimethoprim. This results indicated the serotypes of Salmonella isolates are widely distributed in chicks and ducks. Therefore further epidemiological studies should be carried out in breeder farm and a hatchery.

• Mycobiology
• /
• 제29권1호
• /
• pp.48-53
• /
• 2001

Plants have the ability to acquire an enhanced level of resistance to pathogen attack after being exposed to specific biotic stimuli. To obtain plant growth-promoting rhizobacteria inducing resistance against cucumber anthracnose by Colletotrichum orbiculare, more than 800 strains of rhizobacteria were screened in the greenhouse. Among these strains, Bacillus amyloliquefaciens solate EXTN-1 showed significant disease control efficacy on the plants. Induction of pathogenesis-related(PR-la) gene expression by EXTN-1 was assessed using tobacco plants transformed with PR-1a::$\beta$-glucuronidase(GUS) construct. GUS activities of tobacco treated with EXTN-1 and salicylic acid-treated transgenic tobacco were significantly higher than those of tobacco plants with other treatments. Gene expression analyses indicated that EXTN-1 induces the accumulation of defense-related genes of tobacco. The results showed that some defense genes are expressed by the treatment with EXTN-1 suggesting the similar resistance mechanism by salicylic acid.

• 분석과학
• /
• 제17권1호
• /
• pp.60-68
• /
• 2004

폴리올레핀 부직포는 녹는점이 ${\sim}162^{\circ}C$며 구성비가 40%인 폴리프로필렌과 녹는점이 ${\sim}132^{\circ}C$며 구성비가 60%인 폴리에틸렌으로 구성된것을 이용하였다. 전지격막을 제조하기 위하여 방사선그래프트 법을 이용하여 이 폴리올레핀에 스틸렌을 그래프트 시킨 후 다음으로 술폰산기를 도입하였다. 술폰산기를 갖은 폴리올페핀 부직포를 XPS, SEM, DSC, TGA, 및 Porosimeter를 사용하여 특성 평가 하였다. 술폰화 반응후, 폴리올레핀 부직포에 대한 전해질 보존 (electrolyte retention), 전기저항 (electrical resistance) 및 $K^+$에 대한 운반율과 같은 전기화학적 특성을 조사하였다. 그 결과 술폰산기의 함량이 증가하면 할수록 전해질 보존율은 증가하였으며 반면에 전기저항은 감소하는 사실을 알았다. 또한 술폰산기의 함량이 0.22 ~ 3.60 mmol/g에서 $K^+$의 운반율은 0.90 ~ 0.93이었다.