• Title/Summary/Keyword: storage condition

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Enhanced Stability of Acetyl-L-Carnitine Tablet under Accelerated Storage Condition

  • Kwon, Min-Chang;Wang, Hun-Sik;Shim, Ji-Yeon;Park, Jun-Sang
    • Proceedings of the PSK Conference
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    • 2003.10b
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    • pp.227.1-227.1
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    • 2003
  • Acetyl-L-carnitine (ALC), an endogenous component of L-Carnitine, is the acetyl ester of carnitine that has been reported to be beneficial in depressive disorders and Alzheimer's disease.ALC is so hygroscopic that deliquescence took place when it absorbed moisture by 15%(w/w) in a week and then reached steady-state at 45%(w/w) in 40$^{\circ}C$, 75% RH storage condition. Therefore it is necessary to prevent ALC from absorbing atmospheric moisture. For this purpose, we chose hydroxypropylmethylcellulose phthalate (HPMCP) an enteric polymer, as a film former. (omitted)

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A STUDY ON SURFACE HARDNESS OF COMPOSITE RESINS ACCORDING TO STORAGE CONDITON AND HEAT TREATMENT (보관조건과 열처리에 따른 복합레진의 표면경도에 관한 연구)

  • Kang, Seung-Hoon;Min, Byung-Soon
    • Restorative Dentistry and Endodontics
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    • v.19 no.1
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    • pp.194-204
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    • 1994
  • The purpose of this study was to evaluate the surface hardness of composite resins according to heat treatment. storage condition and storage time. In this study. two kinds of composite resin inlays and one kind of conventional posterior composite resin were used as experimental materials. One hundred eighty composite resin specimens were constructed from composite resin inlays and conventional posterior composite resin. The conditions of this study were heat treatment. storage condition and storage time. Hardness readings were taken from the top surface of each samples using the Vickers microhardness tester(MHT-l. Matsuzawa. Japan}. The following results from this study were obtained: 1. Regardless of storage condition. both composite resin inlay and conventional posterior composite resin have a higher surface hardness under heat treatment than not. 2. Composite resins with heat treatment have a higher surface hardness under dry storage than under water immersion. 3. In case of Clearfil Photo Posterior and Brilliant Enamel with heat treatment. there was no significant difference with time. but Clearfil CR Inlay with heat treatment. there was statistical difference after 24 hours. 4. Surface hardness of composite resins with coarse hybrid type was higher than that of composite resin with fine hybrid type.

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Physicochemical Properties of Red Ginseng on Storage Condition of the Fresh Ginseng (수삼의 저장조건에 따른 홍삼의 이화학적 특성)

  • Kim, Chun-Suk;Jung, In-Chan;Kim, Se-Bong;Yang, Deok-Chun
    • Korean Journal of Medicinal Crop Science
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    • v.13 no.1
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    • pp.52-56
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    • 2005
  • This study was compared the quality of red ginseng and characteristic changes of physicochemical properties according to the storage period (non storage, two days, six days, eight days, ten days) and store temperature $20^{\circ}C, \;34^{\circ}C,\;-10^{\circ}C)$. The water content of the fresh ginseng has a tendency to decrease as storage time increases. When we store the fresh ginseng for 10 days, the ideal storage temperature is considered to be $34^{\circ}C$ degrees. The amount of total nitrogen has a tendency to increase more than that of no storage as storage period approaches to 10 days. In the storage temperature, the amount of total nitrogen has a tendency to increase in the order of 1) room temperature, 2) freezing storage, 3) cold storage more than no storage. Cold storage has larger contents of total phenolic compounds than room temperature and freezing storage according to storage temperature. When we analyze the changes of a relative density of eight elements, ginsenoside $Rb_1,Rb_2,Rc,Rd,Re,Rg_3,Rg_1\;and\;Rg_2$ in red ginseng's saponin Rf according to storage condition, the relative density of $Rb_1\;and\;Rg_1$ against Rf diminishes in each storage condition as storage time increases. And it is also thought that density change of ginsenoside appears because of the materials, and change tendency according to storage condition is not clear. From functional nature on the evaluation of the quality, taste and fragrance of red ginseng according to storage district, it is evaluated that it is most recommendable for red ginseng to be transported and stored in $3{\sim}4$ degrees to keep its best condition.

Comparison between fiber-reinforced polymers and stainless steel orthodontic retainers

  • Lucchese, Alessandra;Manuelli, Maurizio;Ciuffreda, Claudio;Albertini, Paolo;Gherlone, Enrico;Perillo, Letizia
    • The korean journal of orthodontics
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    • v.48 no.2
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    • pp.107-112
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    • 2018
  • Objective: The aim of this study was to examine the properties of fiber-reinforced composite and stainless steel twisted retainers for orthodontic retention. Methods: Three different span lengths (5.0, 8.0, and 14.0 mm) of fiber-reinforced composite were investigated. The three fiber-reinforced composite retainer groups were subdivided according to the storage condition (dry and wet), resulting in a total of six groups. Each stainless steel and fiber-reinforced composite group was comprised of six specimens. The three-point bending flexural test was conducted using a universal testing machine. ANOVA was used to assess differences in the maximum load and maximum stress according to the span length, material, and storage condition. Post-hoc comparisons were performed if necessary. Results: The maximum stress and maximum load were significantly (p < 0.001) associated with the span length, material, and storage condition. The significant interaction between the material and span length (p < 0.001) indicated the differential effects of the material for each span length on the maximum stress and maximum load, with the difference between materials being the highest for the maximum span length. Conclusions: Our findings suggest that fiber-reinforced composite retainers may be an effective alternative for orthodontic retention in patients with esthetic concerns or allergy to conventional stainless steel wires.

Determination of Optimal Storage Condition for Pre-packed Hanwoo Loin

  • Seol, Kuk-Hwan;Park, Tu San;Oh, Mi-Hwa;Park, Beom-Young;Cho, Seong In;Lee, Mooha
    • Food Science of Animal Resources
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    • v.33 no.3
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    • pp.390-394
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    • 2013
  • The aim of this study was to determine the optimal storage condition of pre-packed Hanwoo beef without freezing. Hanwoo loin was purchased from a local distributor at 48 h after slaughter, then sliced in $1.5{\pm}0.5$ cm thickness, and packed in a polyethylene (PE) tray covered with linear low-density polyethylene (LLDPE) film. The studied factors to set the optimal storage condition were chamber temperature (5, 2.5 and $-1^{\circ}C$ for 14 d), cooling method (direct and indirect cooling system), and ultraviolet (UV) light irradiation for beef surface sterilization (0, 30, 60, and 120 min). The changes of pH, thiobarbituric acid reactive substances (TBARS) and number of aerobic bacteria were measured during storage. Beef samples stored in $-1^{\circ}C$ showed the minimal increasing rate in TBARS and microbial growth. After 15 d of storage, there was no significant difference in pH and TBARS values. However, the microbial population of beef stored in direct type cooling chamber ($4.25{\pm}0.66$ Log CFU/g) was significantly lower than that of beef stored in indirect type chamber ($6.47{\pm}0.08$ Log CFU/g) (p<0.05). After 4 d of storage, 60 or 120 min UV light irradiated beef samples showed significantly lower microbial population, and at 14 d of storage, 60 min UV irradiated beef sample showed significantly lower microbial population ($3.14{\pm}0.43$ Log CFU/g) than control ($4.46{\pm}0.13$ Log CFU/g) (p<0.05). However, TBARS values of 60 or 120 min UV light irradiated beef samples were significantly higher than non-irradiated beef sample after 4 d of storage (p<0.05).

Desorption Efficiencies and Storage Stabilities of Ketones in Work Environment (작업장에서 발생되는 케톤류 유기화합물의 탈착효율 및 저장안정성)

  • Kim, Kangyoon;Choi, Sungpil;Ha, Chul-Joo;Choi, Ho-Chun
    • Journal of Korean Society of Occupational and Environmental Hygiene
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    • v.16 no.3
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    • pp.211-221
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    • 2006
  • This study was performed to compare with desorption efficiency and storage stability of CSC and CMS tubes for Ketones in workplace air. 1. The best desorbing solution for CSC tube was 1 % or 3 % dimethylformamide(DMF) in carbon disulfide($CS_2$). The desorption efficiencies were 96.40 % for cyclohexanone, 94.86 % for acetone, 96.96 % for methyl ethyl ketone(MEK), 103.44 % for methyl isobutyl ketone(MIBK), 100.17 % for methyl amyl ketone(MAK), 100.43 % for methyl butyl ketone(MBK), 97.01 % for toluene and 99.33 % for trichloroethylene(TCE). 2. The best desorbing solution for CMS tube was 1 % or 3 % DMF in $CS_2$. The desorption efficiencies were 96.42 % for cyclohexanone, 98.53 % for acetone, 99.67 % for MEK, 105.48 % for MIBK, 100.13 % for MAK, 100.13 % for MBK, 95.42 % for toluene and 98.15 % for TCE. 3. In the storage condition at room temperature($20^{\circ}C$), the recovery rates of cyclohexanone and MEK on CSC tube were rapidly decreased 30.9 % and 50.9 % after 4 weeks, respectively. The recovery rates of all of 6 ketones and 2 nonpolar solvents were shown over 80 % after 1 week in the storage condition of refrigerate temperature($-4^{\circ}C$), and were kept over 80 % after 4 weeks in the storage condition of freezer temperature($-20^{\circ}C$). 4. The recovery rates of cyclohexanone on CMS tube were 80.6 % for 1 week after and 60.5 % for 4 weeks after at room temperature($20^{\circ}C$). The recovery rates of cyclohexanone were shown 80.6 % for 1 week after and 60.5 % for 4 weeks after at $-4^{\circ}C$, and of 6 ketones and 2 non-polar solvents were kept stable over 85 % at $-4^{\circ}C$ and over 97 % at $-20^{\circ}C$ for 4 weeks after. In conclusion, the best desorbing solution was 1 % or 3 % DMF in $CS_2$ and more appropriate sorbent tube for ketones and non-polar solvents was CMS than CSC. We recommend CSC tube would be useful if the samples analyzed within 1 week because CMS tubes are more expensive than CSC tubes. However, if the storage time is needed more than 3 weeks, CMS tubes should be suitable and the storage condition should be below $-20^{\circ}C$.

Evaluation of Impactor's Collection Efficiency on Airborne Bacteria by Type of Agar Media and Storage Condition (배지 종류 및 저장 조건에 따른 impactor의 부유세균 시료 채취 효율 평가)

  • Kim, Ki-Youn;Jang, Gyu-Yeob;Park, Jae-Beom;Kim, Chi-Nyon;Lee, Kyung-Jong
    • Journal of Environmental Health Sciences
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    • v.33 no.2 s.95
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    • pp.145-149
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    • 2007
  • The range of reduction rates of airborne bacteria concentration at 6 hrs, 12 hrs, 24 hrs and 48 hrs, which means a storage time until input of agar media into incubator after air sampling with an impactor. were 15-20%, 25-40%, 35-50% and 55-70%, respectively, compared to initial concentration. Types of agar media and storage thermal condition did not significantly affect a collection efficiency of impactor in terms of evaluating airborne bacteria level (p>0.05). To better improve the impactor's collection efficiency of airborne bacteria, based on the result of this study, it is recommended that the vicinity of $25^{\circ}C$ should be sustained until input of agar media into incubator after air sampling.

Seed Germination of Gastrodia elata Using Symbiotic Fungi, Mycena osmundicola

  • Kim, Yong-Il;Chang, Kwang-Joon;Ka, Kang-Hyeon;Hur, Hyeon;Hong, In-Pyo;Shim, Jae-Ouk;Lee, Tae-Soo;Lee, Ji-Yul;Lee, Min-Woong
    • Mycobiology
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    • v.34 no.2
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    • pp.79-82
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    • 2006
  • The germination rate and longevity of seeds of Gastrodia elata Blume have been observed for 48 weeks using Mycena osmundicola strain H-21, one of fungi stimulating seed germination. Storage condition of post-harvest seeds was observed in the different temperature ranges of $-30^{\circ}C,\;-5^{\circ}C,\;5^{\circ}C\;and\;30^{\circ}C$ for 48 weeks. After storage period of 48 weeks, the germination rate of G elata was 65.7% at $5^{\circ}C$ and 71.6% at $-5^{\circ}C$, respectively. Although the germination rate of G. elata was 77.3% for 11 weeks at $25^{\circ}C$, the germination rate had been decreased gradually to 49.3% at 13 weeks, 0.3% at 23 weeks and then 0% at 25 weeks. The germination rate was reached to the level of 10% for 2 weeks at $-30^{\circ}C$ and then decreased to 0%.

The lyophilization and stability of Salmonella typhi Ty21a (Salmonella thphi Ty21a의 동결 건조와 안정성)

  • 김세란;박동우;전홍렬;김희준;한성순;김기호;김홍진
    • YAKHAK HOEJI
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    • v.43 no.6
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    • pp.793-797
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    • 1999
  • Salmonella typhi Ty21a is an attenuated strain of S. typhimurium and used for oral typhoid vaccine. In an attempt to increase the stability of Ty21a manufacturing typhoid vaccine, we studied about the stability of freeze-dried Th21a including additives at various temperature conditions. In order to investigate the freeze-drying rate of Ty21a according to various absorbance, we lyophilized Ty21a by using 8% sucrose as a stabilizer. The optimal freeze-drying rate of Ty21a was appeared when OD (optical density) value of the growth was between 2.5 and 3.0. To investigate the stability of Ty21a at various temperature, the viability was measured after storaging the freeze-dried Ty21a at the room temperature, cold and freezing condition for 1 week. The viability of Ty21a in cold and freezing storage condition was 5 times more stable than in room temperature. To search the most stable additives for the freeze-dried Ty21a, the viability of Ty21a including additives at the various storage condition was estimated. Mannitol and loctose were the most stable additives. Theses results suggest that the OD value of Ty21a growth, low temperature, mannitol and lactose are important factors for the optimal freeze-drying rate, the stable storage and the most stable additives, respectively.

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