• 약학회지
• /
• 제30권1호
• /
• pp.24-30
• /
• 1986

New antibiotics having moieties of penicillanic acid, cephalosporanic acid and ampicillin on both ends of the central alkylene were synthesized by reacting 6-aminopenicillanic acid (6-APA), 7-aminocephalosporanic acid (7-ACA) and ampicillin with hexamethylene diisocyanate and sebacoyl chloride, respectively. Antibacterial activities of the compounds were also investigated. The compound derived from sabacic acid and ampicillin exhibited an enhanced antibacterial activities against gram-negative bacteria and was found to be a promising wide-spectrum antibiotic.

• The Korean Journal of Physiology
• /
• 제11권2호
• /
• pp.67-71
• /
• 1977

This study was undertaken to investigate the effect of cingulate cortical ablation upon gastric secretion and its components in rats. 23 male rats were divided into the cingulate(N=9) and the operated control(N= 14) groups. Cingulate cortex was ablated through a slit-shaped opening(1 mm in width, 5 mm in length) which was made symmetrically on both sides of, and parallel to, the sagittal suture by removing a bone flap from frontal bone on each side. In the operated control group, the surgical procedure was ended by the removal of the bone flap. Under light ether anesthesia, experimental animals were placed in a restraining jacket of fine mesh wire and gastric juice was collected for 5 hours via a canula which had been inserted through the anterior abdominal wall into the antral portion of the lumen of the stomach. Volume of the gastric juice was measured, and total acid output and free acid output were titrated with 0.04 N NaOH solution by using phenolphthalein and Topfer's reagent at indicator, and chloride ion output was estimated by means of chloridometer. Results obtained were that volume, total acid output, free acid output and chloride ion output of the gastric juice were higher significantly in the cingulate group than in the operated control group. It is inferred from the above results that the cingulate cortex exerts a fascilitatory influence upon gastric secretion and acid output in rats.

• 한국표면공학회지
• /
• 제49권1호
• /
• pp.62-68
• /
• 2016

A chromium-free Ce-based conversion coating formed by immersion in a solution containing cerium chloride and nitric acid on AZ31 magnesium alloy has been studied. The effects of acid pickling on the morphology and the corrosion resistance of the cerium conversion coating were investigated. The corrosion resistance of the conversion coating prepared on AZ31 Mg alloy after organic acid pickling was better than that of inorganic acid pickling. The morphology of the conversion-coated layer was observed using optical microscope and SEM. Results show that the conversion coatings are relatively uniform and continuous, with thickness 1.0 to $1.1{\mu}m$. The main elements of the conversion coating of AZ31 Mg alloy are Mg, O, Al, Ce and Zn by EDS analysis. The electrochemical polarization results showed that the Ce-based conversion coating could reduce the corrosion activity of the AZ31 Mg alloy substrates in the presence of chloride ions.

• Advances in concrete construction
• /
• 제7권2호
• /
• pp.75-85
• /
• 2019

The present study is focused on the mechanical and durability properties of ternary blended cement concrete mix of different grades 30 MPa, 50 MPa and 70 MPa. Three mineral admixtures (fly ash, silica fume and lime sludge) were used as a partial replacement of cement in the preparation of blended concrete mix. The durability of ternary blended cement concrete mix was studied by exposing it to acids HCl and $H_2SO_4$ at 5% concentration. Acid mass loss factors (AMLF), acid strength loss factor (ASLF) and acid durability factor (ADF) were determined, and the results were compared with the control mix. Chloride ions penetration was investigated by conducting rapid chlorination penetration test and accelerated corrosion penetration test on control mix and ternary blended cement concrete. From the results, it was evident that the usage of these mineral admixtures is having a beneficiary role on the strength as well as durability properties. The results inferred that the utilization of these materials as a partial replacement of cement have significantly enhanced the compressive strength of blended concrete mix in 30 MPa, 50 MPa and 70 MPa by 42.95%, 32.48% and 22.79%. The blended concrete mix shown greater resistance to acid attack compared to control mix concrete. Chloride ion ingress of the blended cement concrete mix was low compared to control mix implying the beneficiary role of mineral admixtures.

• 콘크리트학회논문집
• /
• 제20권4호
• /
• pp.439-449
• /
• 2008

혼화재를 사용한 혼합콘크리트는 콘크리트의 품질을 개선시키며 지속가능한 콘크리트구조물의 건설에도 기여하고 있다. 실리카퓸 (SF), 고로슬래그미분말 (GGBS), 플라이애쉬 (PFA) 등의 시멘트계 결합재는 고성능콘크리트의 혼화재로서 인식이 증가되고 있으나, 삼성분계 혼합콘크리트에 대한 연구는 매우 제한적이며, 특히 염해에 의한 부식저항성 측면에서의 연구는 상당히 취약한 실정이다. 본 연구에서는 보통포틀랜드시멘트의 경우를 50%의 치환율로 고정한 후 고로슬래그미분말의 경우는 $20{\sim}40%$, 실리카퓸의 경우에는 $5{\sim}15%$, 플라이애쉬의 경우는 $10{\sim}45%$로 치환한 경우의 각종 배합에 의한 염해부식저항성에 관한 실험연구를 수행하였다. 삼성분계 혼합콘크리트의 염해부식저항성을 평가한 본 연구에서는, 수행 실험으로서 부식 저항성 실험, 염소이온 고정화 능력 실험, 급속 염화물 촉진 실험, 산중성화 저항 능력 실험 등을 수행하였다. 연구 결과로서, 삼성분계 콘크리트는 미세구조를 치밀화 하여 염소이온의 이동을 지연시키고 있음을 확인하였다. 또한, 염분을 함유한 삼성분계 혼합콘크리트 내의 염소이온 고정화 능력 및 산중성화 저항 능력이 크게 개선되고 있음을 확인하여 염해에 대한 부식 저항성이 향상됨을 알 수 있었다.

• 농업과학연구
• /
• 제13권1호
• /
• pp.130-138
• /
• 1986

즉석에서 이용할 수 있는 생고추의 파쇄 제품을 개발하기 위한 기초자료를 얻기 위하여 생고추를 파쇄한 후 밀봉함에 있어서의 첨가물질, 포장재료, 저장온도 및 기간이 제품의 품질 성분에 마치는 영향을 검토하여 다음과 같은 결과를 얻었다. 1. 파쇄한 생고추에 15%의 Sodium chloride를 첨가하면 Sodium chloride 무첨가구에 비하여 산도, Capsanthin 및 Capsaicin 잔존량 면에서 효과가 현저하였다. 2. 파쇄한 생고추의 밀봉 저장에는 Polyethlene film 보다 Polyvinylidene chloride film이 효과적이었다. 3. 파쇄한 생고추를 Polyvinylidene chloride film으로 밀봉 저장할 정우 Capsanthin의 분해는 온도가 높을수록 심하였고 Capsaicin의 분해는 저장 초기에 빨랐으며 Sodium chloride 첨가에 의하여 현저하게 저하하였다. 4. 저장중에 있어서 Vitamin C의 분해는 저온에서 보다 고온에서 심하였고 Sodium chloride 첨가에 의하여 상당히 억제되었다. 5. 저장중의 총균수 및 젖산균수의 증가는 Sodium chloride 첨가에 의하여 크게 억제되었고 저장온도에 따르는 차이는 거의 인정되지 않았다.

• 대한미생물학회지
• /
• 제35권1호
• /
• pp.1-8
• /
• 2000

In order to explore the potential of ascorbic acid supplementation for the prevention and treatment of herpes simplex viral diseases, plaque reduction assays were performed. Ascorbic acid as well as copper chloride/ferric chloride were added to wells containing Vero cells infected with herpes simplex virus type 1 (HSV-1), and the infectivity of HSV-1 was determined. Since copper and iron are major transition metals in human plasma, near the normal human plasma concentrations of them were used for experiments. When Cu(II) and Fe(III) were applied, there were no significant differences between virus control and Cu(II)/Fe(III)-treated groups. But, when appropriate concentrations of ascorbic acid were added to wells, meaningful differences between control and ascorbate-treated groups were found. In the presence of Cu(II)/Fe(III) at $5.8/3.7\;{\mu}M$, 72-h treatment with ascorbate at $50\;{\mu}M$ reduced HSV-1 infections to $10.77%{\pm}4.25%$ (P < 0.001) and $500\;{\mu}M$ did to $3.06%{\pm}1.62%$ (P < 0.001). Moreover, the cytotoxicities for Vero cells at those concentrations were insignificant (P > 0.05). Current recommended dietary allowance (RDA) of ascorbic acid is 60 mg/day, and the oral intake of 60 mg/day of ascorbic acid yields plasma ascorbic acid at 45 to $58\;{\mu}M$ in a healthy adult man. Therefore, the results of this study suggest that the maintenance of appropriate level (more than $50\;{\mu}M$) of ascorbic acid in human plasma by appropriate amount (more than the RDA) of ascorbic acid supplementation may be helpful for the prevention and treatment of diseases caused by HSV -1 in an adult man. In addition, this study also suggests that ascorbic acid may be useful for the prophylaxis of fatal HSV-1 infections in neonates and the prevention of HSV-1 reactivation in immunocompromised hosts.

• 대한화장품학회지
• /
• 제42권4호
• /
• pp.413-420
• /
• 2016

하이드록시 산(hydroxy acid, HA)은 피부 각질층에 대한 박리효과로 노화방지와 피부 보습을 높이는데 효과를 보여, 피부 외용제와 화장품으로서 많은 활용을 하고 있다. 그 중에서 가장 효과적으로 빠른 시간 내에 나타나는 각질 박리는 화장품 제형 pH에 의해 효과를 보이는 것으로 많은 보고가 있다. 그러나 pH에 의한 자극, 부작용에 의한 염려로 인해 사용에 많은 어려움이 있다. 본 연구의 목적은 피부 각질층에 (1) 하이드록시 산의 농도와 (2) 종류, (3) pH를 변화시킨 화장품을 인체 피부에 도포하여 각질 박리 효과에 대한 영향을 측정하는 데에 있다. 건강한 성인 22명을 대상으로 하박 내측에 DHA (dihydroxyacetone), DC (dansyl chloride)로 피부 표면 각질을 염색하여, 시험제품을 도포한 뒤 각질박리 효과를 측정하였다. (1) GA (glycolic acid)의 농도에 따라 각질 박리 효과는 농도 의존적으로 증가하는 것으로 나타났다. (2 )하이드록시 산의 종류에 따라 pH를 산성과 중성으로 제조한 제품을 대상으로 각질 박리 효과를 측정한 결과, 중성 pH의 GA는 각질 박리 효과가 나타나지 않았다. 이에 반해 SA (salicylic acid)는 산성 pH와 중성 pH에서 모두 통계적으로 유의한 각질 박리 효과가 나타났다. (3) 중성 pH의 SA는 DHA와 DC로 염색한 피부 표면에서 모두 우수한 각질 박리 효과를 나타내었다. 이러한 결과는 pH에 민감한 사람들에게 각질 박리 효과를 기대하는 화장품을 사용할 수 있는 기회를 제공하며, 피부 장벽의 손상 없이 안전한 화장품을 제조할 수 있을 것이라 사료된다.

• Corrosion Science and Technology
• /
• 제17권5호
• /
• pp.203-210
• /
• 2018

This paper compares the inhibition properties of aspartic and lactic acid salts with nitrite ions and their effect on critical chloride concentration. The tests were carried employing carbon steel specimens in saturated lime solution with varying pH in the range between13 to 13.6. The critical chloride concentration was estimated through multiple specimen potentiostatic tests at potentials in the usual range for passive rebar in the alkaline concrete of atmospheric structures. During tests, chloride salt was added every 48 h until all the specimens showed localized attacks. The cumulative distribution curves, i.e. the number of corroded specimens as a function of the chlorides concentration was obtained. Furthermore, IR spectra were recorded for the evaluation of the presence of the organic inhibitors on the passivity film. The results confirmed the inhibitory effect of 0.1M aspartate comparable with nitrite ions, at a similar concentration. Addition of calcium lactate did not result in an increase in the critical chloride concentration. However, the formation of a massive scale containing the substance that could reduce the corrosion propagation was observed.

• 콘크리트학회논문집
• /
• 제17권4호
• /
• pp.663-670
• /
• 2005

The present study concerns the influence of binder type on the chloride-induced corrosion being accompanied by the chloride threshold level (CTL), chloride transport and as their results the corrosion-free lift. Two levels of cement content, $30\%$ PFA and $65\%$ GGBS concrete were employed. It was found that the most dominant factor to the CTL is the entrapped air void content at the steel-concrete interface, irrespective of the chloride binding capacity, binder type and acid neutralisation capacity of cement matrix. The CTL for lower interfacial air void contents was significantly increased up to $1.52\%$ by weight of cement, whereas a same mix produced $0.35\%$ for a higher level of voids. Because of a remarkable reduction in the diffusion fur GGBS concrete, its time to corrosion ranges from 255 to 1,250 days, while the corrosion-free life for control varies from 20 to 199 days sand for $30\%$ PFA concrete from 200 to 331 days.