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        검색결과 59

        1.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Background: Canine induced pluripotent stem cells (iPSCs) are an attractive source for veterinary regenerative medicine, disease modeling, and drug development. Here we used vitamin C (Vc) to improve the reprogramming efficiency of canine iPSCs, and its functions in the reprogramming process were elucidated. Methods: Retroviral transduction of Oct4, Sox2, Klf4, c-Myc (OSKM), and GFP was employed to induce reprogramming in canine fetal fibroblasts. Following transduction, the culture medium was subsequently replaced with ESC medium containing Vc to determine the effect on reprogramming activity. Results: The number of AP-positive iPSC colonies dramatically increased in culture conditions supplemented with Vc. Vc enhanced the efficacy of retrovirus transduction, which appears to be correlated with enhanced cell proliferation capacity. To confirm the characteristics of the Vc-treated iPSCs, the cells were cultured to passage 5, and pluripotency markers including Oct4, Sox2, Nanog, and Tra-1-60 were observed by immunocytochemistry. The expression of endogenous pluripotent genes (Oct4, Nanog, Rex1, and telomerase) were also verified by PCR. The complete silencing of exogenously transduced human OSKM factors was observed exclusively in canine iPSCs treated with Vc. Canine iPSCs treated with Vc are capable of forming embryoid bodies in vitro and have spontaneously differentiated into three germ layers. Conclusions: Our findings emphasize a straightforward method for enhancing the efficiency of canine iPSC generation and provide insight into the Vc effect on the reprogramming process.
        4,000원
        2.
        2023.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The objective of the present experiment was to investigate the effects of dietary vitamin C (VC), vitamin E (VE), and betaine (BT) supplementations on productive performance, egg quality, relative organ weights, liver visual characteristics, antioxidant status, immune response, and stress indicator in laying hens raised under heat stress conditions. A total of 280 47-wk-old Hy-Line Brown laying hens were allotted to 1 of 4 dietary treatments with 7 replicates in a completely randomized design. Each replicate had 10 birds per cage. The basal diet was formulated to meet or exceed the requirement estimates for Hy-Line Brown laying hens. Three additional diets were prepared by adding 250 mg/kg VC, 250 mg/kg VE, or 3,000 mg/kg BT to the basal diet. The experimental diets and water were provided to hens on an ad libitum basis for 8 wk. Average daily room temperature and relative humidity were 30.7±1.41℃ and 72.5±11.61%, respectively. Results indicated that hens fed diets containing 250 mg/kg VE had a less (p<0.05) egg production rate than other dietary treatments. For egg quality, hens fed diets containing 3,000 mg/kg BT had a less (p<0.05) eggshell thickness than those fed the diets containing 250 mg/kg VC or 250 mg/kg VE. For antioxidant status, there was a tendency (p=0.09) for the least malondialdehyde (MDA) concentrations in the liver for BT treatment. A tendency (p=0.05) was observed for less blood heterophil:lymphocyte ratio in BT treatment as compared to other treatments. In conclusion, dietary supplementation of 250 mg/kg VC, 250 mg/kg VE, and 3,000 mg/kg BT has no beneficial effects on productive performance, egg quality, relative organ weights, liver visual characteristics, and immune responses of laying hens raised under the current heat stress conditions. However, dietary supplementation of 3,000 mg/kg BT alleviates antioxidant status and stress response of laying hens exposed to heat stress.
        4,200원
        3.
        2023.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Carbon nanodots (CNDs) are 0D quasi-spherical nanoparticles that are less than 10 nm in size. CNDs that possess surface functional groups such as hydroxyl, amino, and carboxyl groups have been demonstrated to scavenge free radicals efficiently and effectively, resulting in them being beneficial for cosmetic and cosmeceutical applications. In this study, we successfully prepared novel CNDs, namely black VC, using vitamin C (VC) as a promising precursor. Black VC was prepared by a facile one-step method based on short-time microwave irradiation. The properties of black VC were characterized by transmission electron microscopy (TEM) analysis, X-ray diffraction (XRD), high-resolution X-ray photoelectron spectroscopy (XPS), Fourier transform infrared (FTIR) spectroscopy, and UV–vis spectrophotometry. Radical scavenging, cell viability, and anti-pollution activity assays were also conducted to demonstrate the functionalities of black VC. The developed black VC exhibited lower cytotoxicity and better antioxidant, metal chelating ability, and anti-pollution activities than its precursor. These results provide a new approach for developing advanced antioxidants for innovative cosmetic formulations using a simple microwave treatment method. However, black VC retained some problems of its precursor in the form of low stability, which is likely to be a challenge for its cosmeceutical application.
        4,300원
        4.
        2022.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study evaluated the effect of a combination of acetaminophen (AAP), vitamin C (VC) and thioctic acid (TA) on reducing serum cortisol concentrations in mice with foot-and-mouth disease (FMD) vaccination. For 5 days from 3 days before FMD vaccination to 2 days after vaccination, mice were orally administered with AAP 600 mg/kg feed (n=25, AAPT), combination of AAP 600 mg and VC 200 mg per kg feed (n=25, AVCT) and combination of AAP 600 mg, VC 200 mg and TA 20 mg per kg feed (n=25, AVTT), respectively. From day 1 to day 7 after FMD vaccination, the cortisol concentration of all groups treated with the drug was significantly decreased compared to that of the positive control group with FMD vaccination (p<0.05). In conclusion, the combined treatment of AAP, VC and TA was the most effective in relieving stress from FMD vaccination compared to the single treatment.
        4,000원
        5.
        2022.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this study, a comparative dissolution experiment was conducted between an immediate-release and a controlled-release vitamin C tablet applied with a technology to control the dissolution of vitamin C to maintain the vitamin C level in the human body. In order to confirm the dissolution rate (%) of vitamin C tablets, HPLC determination was conducted based on the dissolution test methods in the ‘Korean Pharmacopoeia (No. 2020-88),’ ‘Guidelines on Specifications of Dissolution Tests for Oral dosage Forms,’ and ‘Standard and Specifications for Health Functional Foods (No. 2020-63)’ from Ministry of Food and Drug Safety (MFDS). In addition, the dissolution pattern between the immediate-release tablet and the controlled-release tablet was comparatively analyzed. The analysis result confirmed that the immediate-release vitamin C tablet was 100% dissolved after 45 minutes, while the controlled- release vitamin C tablet was 100% dissolved after 480 minutes (8 hours). Furthermore, the dissolution rate (%) at 60 minutes was slower than that of the immediate-release vitamin C tablet. Based on these results, this study confirmed that the dissolution rate (%) test and development of controlled-release tablets containing vitamin C as the main component a re possible.
        4,000원
        6.
        2021.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this study the effect of vitamin C administration on pregnancy rates during summer heat stress in dairy cows was examined. A total of 80 Holstein-Friesian cows were divided into control and treatment groups (n = 40 each). Control group animals were given 10 mL isotonic normal saline, and treatment group, Vitamin C (4 mg/kg) on artificial insemination day (day 0) and 4th, 8th and 12th day post insemination. Pregnancy diagnosis was performed on 30th day post insemination by ultrasonography. Blood samples were randomly taken from 11 animals from each group. Serum P4, GSH, MDA and plasma 8-OHdG levels were determined by using ELISA method. Results showed that 8-OHdG levels were lower in treatment group on day 4, 8 and 12 (p < 0.05) compared with the control group. Similarly, pregnancy rate was higher in treatment group (32.5%) than control (22.5%), respectively. However, MDA, P4 and GSH levels were similar in both groups at 4th, 8th and 12th day. A gradual increase in P4, and MDA levels, and a strong positive correlation between 0, 4th (r = 0.54), 4, 8th (r = 0.59) and 8, 12th (r = 0.51) day was found. Similarly, GSH levels also showed positive correlation at days 0, 4th (r = 0.47) and 4, 8th (r = 0.56). However, a strong negative correlation (r = -0.56) between MDA day 0, and GSH day 8 was found. In conclusion, vitamin C application during insemination period in postpartum cows increases pregnancy rate, and reduces oxidative stress metabolite 8-OHdG levels.
        4,000원
        7.
        2021.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study investigates the relationship between vitamin C intake and obesity prevalence among Korean adults. Based on data of the Korean National Health and Nutrition Examination Survey (2016-2017), a total of 1,356 participants were included in this analysis. Increasing the dietary vitamin C intake resulted in a significantly decreased occurrence of BMI obesity prevalence (p for trend=0.0194) and WC obesity prevalence (p for trend=0.0452). Moreover, increasing the dietary vitamin C intake of Korean adults having a high frequency of eating breakfast resulted in significantly decreased BMI obesity prevalence (p for trend=0.0406) and WC obesity prevalence (p for trend=0.0432). Among the Korean adults who ate out frequently, decreased BMI obesity prevalence was determined with increased intakes of dietary vitamin C (p for trend=0.0193) and total vitamin C (food and dietary supplements) (p for trend=0.0429), whereas significant decrease in WC obesity prevalence was observed with increased dietary vitamin C intake (p for trend=0.0484). Our results provide conclusive evidence that consumption of dietary vitamin C is associated with obesity prevalence in Korean adults, according to their habits of eating breakfast and frequency of eating out.
        4,300원
        8.
        2018.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구는 아질산나트륨 및 비타민 C의 대체로 첨가한 수벌번데기 분말이 유화형 소시지의 이화학적 품질 특성에 미치는 영향을 구명하고자 하였다. 시료는 아질산염, 비타민 C 및 수벌번데기 분말의 첨가 수준에 따라 각각 아질산나트륨 150 ppm+비타민 C 200 ppm(대조구), 아질산나트륨 75 ppm+ 비타민C 100 ppm+수벌번데기 분말 6.015%(T1) 또는 수벌번데기 분말 12.03%(T2)을 첨가하여 제조한 후 4℃에 30일 동안 저장하였다. pH는 수벌번데기 분말의 첨가 수준이 증가함에 따라 현저하게 감소하였다(p<0.05). 일반성분 함량은 수벌번데기 분말의 첨가 수준이 높은 소시지에서 낮은 수분 및 조단백질 함량과 높은 조지방 및 조회분 함량을 보였다 (p<0.05). 지방산 조성은 T1과 T2가 대조구에 비해 포화지방산 함량이 높았으나(p<0.05), 불포화지방산 및 다가불포화지 방산 함량은 낮았다(p<0.05). 색깔은 T1과 T2가 대조구보다 현저하게 낮은 명도(L*) 및 적색도(a*)와 높은 황색도(b*) 및 hue-angle(h°)을 보였으며(p<0.05), T2의 경우 가장 낮은 chroma(C*)를 나타내었다(p<0.05). 지방산화물(TBARS) 함량은 T2가 가장 높았으며(p<0.05), 특히, 대조구보다 2배 이상 높았다. 조직감은 T1과 T2가 저장기간 동안 대조구에 비해 단단한 특성을 보였다(p<0.05). 따라서 유화형 소시지에서 수벌번데기 분말의 첨가는 색깔, 지방산화안정성 및 조직감에 부정적인 영향을 미치는 것으로 나타나, 아질산나트륨 및 비타민 C 대체 효과가 없었다
        4,000원
        9.
        2018.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        알츠하이머병의 발병원인과 기전에 대하여 많은 연구가 진행되었으나, 아직까지 완전히 밝혀지지 않고 있다. 이에 본 연구에서는 STZ로 유도된 세포독성으로부터 노인성 질병의 예방과 항산화 효과로 잘 알려진 비타민 C를 이용하여 SH-SY5Y 신경세포 내 보호 기전을 살펴보고자 하였다. 본 연구 결과에 의하면, STZ를 SH-SY5Y 신경세포에 처리하였을 때, 세포사멸이 유도되는 것을 확인하였으며, 비타민C를 전처리함으로써 세포생존도가 증가하는 것을 확인하였다. 비타민 C가 신경세포를 보호하는 기전을 알아보기 위하여 세포자멸사 과정에서 신호전달을 통해 다양한 유전자를 발현시키는 MAPKs의 인산화를 살펴보았다. 비타민 C 처리시 ERK의 인산화가 증가하며, 세포증식을 유도하는 것으로 확인하였으며, ERK와는 반대로 염증, 세포사멸과 관련된 JNK의 인산화는 비타민 C에 의해 인산화가 억제되는 것으로 확인되었다. 또한 STZ는 Bax 단백질의 발현 증가와 Bcl-2 단백질의 발현을 감소시켰으며, apoptosis antibody array로 확인한 결과, Cytochrome C가 유도됨을 확인하였다. 이뿐만 아니라, 비타민 C 처리에 의해 Bcl-2가 증가하여 세포사멸이 억제되는 것을 확인하였으며, 항산화 효소인 Sod-1의 발현을 증가하는 것 또한 확인하였다. 이는 비타민 C가 항산화 방어체계를 강화시켜 STZ에 의한 세포손상을 보호하는 것으로 사료된다. 본 연구를 통하여 STZ로 유도된 SH-SY5Y 신경세포 손상 에서 비타민 C가 여러 기전을 통하여 세포자멸사를 억제하여 세포를 보호하는 효과가 있는 것을 확인할 수 있었다. 그러나 연구는 일부 기전들만을 확인한 것으로 추후 연구에서는 다양한 비타민 C의 농도 및 처리시간에 따른 기전의 차이를 분석하고, 실험동물을 통한 검증 및 스트렙토조토신에 의한 아밀로이드베타와 타우의 관련성을 확인하고자 한다.
        4,000원
        11.
        2017.11 구독 인증기관·개인회원 무료
        Salt is generally used for food seasonings and preservations as a common ingredient. However, excess salt intake has generated health issues such as high blood pressure, osteoporosis, stroke, and heart diseases. Recently, desires and interests of low-salt cooking have been increased among people who want healthy diets. The aim of study was to compare the physicochemical characteristics of a fermented squid sauce added with vitamin C and commercial low-salt soy sauces. Thawed and crushed squids were fermented until the solid squid became liquid at 25°C with an addition of 5% (g/g) vitamin C. Then, fermented squid sauce was heated at 100°C for 30 min and filtered. All samples were measured in multiple aspects of amino acid nitrogen, salt, sugar and water content, pH, chromaticity and brown color, and sensory test. In the results, color values showed no significantly difference between all the samples (p>0.05). Water content value of the fermented squid sauce was the highest among samples. Brown color, salt contents and sugar contents of the fermented squid sauce were significantly different than other low salt soy sauces with an exception of the sauce made with functional salt. These results showed a similar tendency as those of sensory evaluation. As conclusion, the possibility of fermented squid sauce added with vitamin C showed a possibility as a candidate of low-salt soy sauce.
        12.
        2017.05 구독 인증기관·개인회원 무료
        Introduction Porcine embryonic stem cells (pESCs) derived from cloned embryos might be a useful animal model in biomedical research, however, establishment of cloned pESCs is difficult by its incomplete nuclear reprogramming. Here, we report the improved development competence of porcine cloned embryos by vitamin C (VC) supplement to establish the pESCs. Materials and Methods Slaughterhouse-derived oocytes were in vitro matured for 44h and parthenogenetic and cloned embryos were produced using matured oocytes. Both of embryos were cultured for 6 days in PZM-5 media and development rates were examined. Four different concentration of VC (0, 25, 50, 100, and 200 μg/ml) was supplemented in IVM and IVC media and preimplantation developments in the 5 groups were compared in both of embryos Results and Discussion In the cleavage rates of IVM group, significantly higher rate was shown in 50 mg/ml group than other groups (84.5 ± 0.6% vs. 69.8 ± 5.5, 75.7 ± 1.8, 80.4 ± 0.2, 72.4 ± 0.1%; P<0.05), respectively. Significantly higher rates of blastocyst development also were shown in 50 mg/ml group than other groups (27.0 ± 2.0% vs. 20.4 ± 1.4, 22.1 ± 1.3, 23.7 ± 1.2, 19.6 ± 1.3%; P<0.05), respectively. In the cleavage rate of IVC group, non-significantly different with each group (84.0 ± 1.3, 86.7 ± 1.0, 88.4 ± 1.4, 76.7 ± 3.0, 64.6 ± 4.4; P<0.05). In the blastocyst rate of IVC group, significantly higher rate was shown in 25mg/ml and 50 mg/ml group than other groups (22.3 ± 1.7, 23.8 ± 1.7% vs. 19.1 ± 1.3, 15.9 ± 1.0, 5.8 ± 1.5%; P<0.05) In conclusion, supplement of 50μg/ml of VC in IVM and IVC media enhanced the development of porcine parthenogenetic embryos and these results will be a helpful information in the development of porcine cloned embryos and derivation of its embryonic stem cells.
        13.
        2016.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study aimed to investigate the concentration of vitamin C in Momordica charantia (MC) by cultivar, harvest time, and maturity. The methods for determining vitamin C levels were validated by measuring their linearity, specificity, limit of detection (LOD), limit of quantification (LOQ), precision, and accuracy using HPLC. Results showed high linearity in the calibration curve, with a coefficient of correlation (R2) of 0.9994. The LOD and LOQ values for vitamin C were 0.05 and 0.16 μg/mL, respectively. The relative standard deviations (RSDs) for intra- and inter-day precision of vitamin C measurements were 2.34 and 1.34%, respectively. Depending on cultivar, the concentration of vitamin C in MC varied from 20.75~107.31 mg/100 g, fresh weight, with an average level 68.85±25.57 mg/100 g, FW. When MC was analyzed by harvest time, the 20150612 MC showed the highest amount of vitamin C (113.20±1.89 mg/100 g, FW). On the other hand, the highest vitamin C content by maturity was 48.59±0.87 mg/100 g, FW (15 day old MC). This information on the comparative vitamin C levels of MC might be useful to food scientists and should be explored for functional food development.
        4,000원
        14.
        2016.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The objective of this study was to investigate the effect of amino acid and vitamin C supplementation on the quality attributes of top round (TR) muscle from Korean cattle (Hanwoo). Sixteen-month-old steers were divided into three different feeding groups and raised until they were 28 months old. A control group (9 heads) was fed a basal diet and rice straw, whereas two experimental groups (8 heads/group) were fed a basal diet and rice straw supplemented with rumen-protected amino acids (≥16.0% L-lysine monohydrochloride, ≥8.0% DL-methionine) and vitamin C at a dose of 100 g/head/day (AA+VC group) or only vitamin C at 100 g/head/day (VC group). After slaughter, TR muscle (M. semimembranosus) was collected from carcasses and used to measure the quality attributes. Crude fat content was significantly higher (p<0.05) in the AA+VC group than in the VC group. No significant difference was observed for water-holding capacity and shear force value between the control, AA+VC, and VC groups. Contents of the free amino acids (FAAs) glycine, aspartate, and glutamate were significantly higher (p<0.05) in the VC group than in the control group. Sensory evaluation of tenderness and flavor preference revealed significantly higher scores (p<0.05) in the AA+VC group than in the control group. These findings suggest that vitamin C supplementation increases the contents of some FAAs, and the combined supplementation of amino acids and vitamin C improves the marbling and sensory attributes of TR muscle in Hanwoo.
        4,000원
        15.
        2015.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구는 방풍나물의 인공광 식물공장에서 재배시스템에 따른 생육, 비타민 C, 아미노산함량, 수량에 미치는 영향을 구명코자 실시하였다. 박막수경(NFT), 배지경 (Perlite), 분무경(Aeroponics) 등 3처리를 하였다. 초장은 NFT 처리에서 10.2cm 가장 길었으며, Perlite 처리에서 8.9cm로 가장 짧았다. 주당 엽 생체중은 Perlite, NFT, Aeroponics순으로 무거웠다. 총 페놀 함량은 Aeroponics가 117.84mg·100g-1 GE로 가장 높았고, NFT 98.57mg·100g-1 GE, Perlite 74.62mg·100g-1 GE 순으로 재배 방법에 따라 차이를 나타냈다. 총 플라보노이드는 Aeroponics에서만 0.12mg·100g-1가 검출되었으나, NFT와 Perlite 처리구에서는 검출되지 않았다. 비타민 C 함량은 Aeroponics가 108.23mg ·100g-1으로 가장 높았으며, Perlite가 88.05mg·100g-1, NFT가 80.83mg·100g-1으로 처리에 따라 통계적인 유의성을 나타냈다. 총 식이섬유소 함량은 Aeroponics가 Perlite와 NFT보다 높았다. Cystein 함량은 Aeroponics에서 46.76mg ·100g-1로 가장 높았으며, methionine 함량은 Perlite가 75.64mg·100g-1 로 가장 낮았다. 무기질 함량은 모든 처리에서 K, Ca, P, Mg 순으로 높았다.
        4,000원
        19.
        2015.06 구독 인증기관 무료, 개인회원 유료
        In order to use as a new functional food material, we analyzed the chemical components including the organic compounds, minerals and vitamin C of canola honey which were produced in South Korea. The condensed rate of methanol extraction in honey was 90.5% and main organic compounds that extract by organic solvents in GC-MS analysis were propyl carbinol, cyclopentane, trichloromethane, vinegar naphtha and so on. Also, main aromatic compounds that extract by organic solvents in SPME analysis were diisooctyl adipate, furole, furaldehyde, cyclotetrasiloxane, trisulfide and many more. As proximate composition, crude ash content was lower than acacia honey (0.06%) and manuka honey (0.24%) by 0.01%, and crude protein was higher than acacia honey (0.10%) by 0.23%, but the crude fat of canola and manuka honey was lower content than acacia honey (0.44%) by 0.10%. Free sugar that analyze by HPLC consisted of fructose 44.11%, glucose 22.72%, and total sugars was 66.83%. Minerals by ICP analysis were detected total 15 kinds, Na 7.157 ppm>Ca 5.934 ppm>Si 4.049 ppm>K 1.443 ppm>Mg 1.218 ppm etc. Vitamin C was not detected.
        4,000원
        20.
        2014.07 구독 인증기관 무료, 개인회원 유료
        This is an initial work on a research project which will ultimately test a battery of hypotheses relating to the drivers of consumers’ willingness to buy of Vitamin C OTC. This initial work outlines the product category, the market, and presents the initial theoretical framework to be investigated. Dietary Supplement constitutes a very significant business market in Thailand. Consumers in Thailand consume dietary supplements on a daily, continual basis to supplement their daily dietary intake. More importantly, they consume them as a preventive measure to off-set an environment of ever growing pollution, pressure to perform and stress. The market for dietary supplements is growing, and firms operating in this market are interested to understand the factors and variables related to consumers’ willingness to buy on these dietary supplements. Consumers can also benefit from research insights as the consumption of dietary supplement is not without criticism (e.g. Braun et al., 2009; Timbo et al., 2006). Food supplements or Dietary supplements (EU1) is the official designated term for this product category in the United Stated of America (U.S. FDA 1994). Thailand (ACCSQ-TMHS, 2006), are classified as food products containing micronutrients and its intention is to supplement the normal diet (Greger, 2001). According to Kearney (2010), consumers have increasing levels of focus on the importance of health, which the increased focus on health coincides with an increased availability of health information, which in turn is fueled by the underlying demands of an aging population and an increase in lifestyle diseases. In the EU, the use of supplements is widely practiced in the general population. Statistics reveal that 47% of German women and 41% of German men regularly take supplements consisting of vitamins, and minerals (Reinnert, Rohrmann, Beckers & Linseisen, 2007). The sales ratio in the Thai market between general nutrients and vitamins is approximately 55 to 45 percent. According to the latest IMS Health Thailand report as of end September 2013 (see Table), it is noted that in Thailand alone, the domestic consumption of general nutrients and vitamins as food supplements has increased by more than four folds from 2004 to 2013 (Thai Baht 1.27 billion in 2004 to 5.46 billion in 2013). The majority of this increase occurred from 2011 to 2013. Most of these products are imported from the US. Other major producers and exporters of these products are Ireland, France, Switzerland, Japan, Netherlands, Germany and Australia; whereas Japan, Philippines, Singapore and Vietnam are major exporters of raw materials into Thailand for further refinement (Arunanondchai 2007). In Thailand, exercise used to be the main way to achieve a healthy life. There is, however, a growing belief that healthy food and food supplement consumption is important to be healthy. The present project studies the use of Vitamin C as an example of a dietary supplement, which is widely consumed in Thailand. Vitamin C (L-ascorbic acid or Ascorbate) is the generic descriptor for compounds having antiscorbutic activity. Most animals can synthesize Vitamin C from D-glucose but humans and other primates, together with guinea pigs, fruit bats, some Passeriformes birds, some fish and some insects, are exceptions. Vitamin C is a reducing agent (antioxidant) and it is likely that all of its biochemical and molecular functions relate to this property. In humans, Vitamin C acts as an electron donor for eight enzymes, of which three are involved in collagen hydroxylation (including aspects of norepinephrine, peptide hormone and tyrosine metabolism) and two are involved in carnitine biosynthesis (Dunn et al (1984), Eipper et al (1993, 1992), Kaufmann (1974), Kirirkko & Myllyla (1985), Levine et. al, (1991), Procop & Kiviikko (1995), Peterkovsky (1991), Rebouche (1991)). Vitamin C is sold through various distribution channels, including the over-the-counter (OTC) market in Thailand with limited restriction from the Thai FDA. OTC drugs are medicines that may be sold directly to a consumer without a prescription from a healthcare professional, as compared to prescription drugs, which may be sold only to consumers possessing a valid prescription. The term OTC may be somewhat counterintuitive, since, in many countries, these drugs are often located on the shelves of stores like any other packaged product. In contrast, prescription drugs are almost always passed over a counter from the pharmacist to the customer. Some drugs may be legally classified as over-the-counter (i.e., no prescription is required), but may only be dispensed by a pharmacist after an assessment of the patient's needs and/or the provision of patient education. In many countries, a number of OTC drugs are available in establishments without a pharmacy, such as general stores, supermarkets, gas stations, etc. Regulations detailing the establishments where drugs may be sold, who is authorized to dispense them, and whether a prescription is required vary considerably from country to country. To simplify, any medicine that can be sold over the counter for symptomatic relief of minor or self-limiting ailments without the prescription of a registered medical practitioner is an OTC Medicine. OTC Medicines differ from Prescription Medicines in terms of Margin of Safety, Advertising and Distribution. The project will address a combination of both intrinsic and extrinsic driving factors in pharmaceutical products, including vitamins that can potentially lead to a better and clearer understanding on how consumers perceive the product quality, get influenced by expert opinion, and manage perceived risk when deciding whether or not to buy. Three potential drivers will be investigated in this project for their impact on willingness to buy: Country of Origin image, brand image, and expert opinion. Further, the framework suggests that the relationship between these three drivers and consumers’ willingness to buy is mediated by their perceived risk. Basing on the requirement of developing a theoretical framework to answering these questions, it is foreseen that both practical and implicative results derived from the OTC pharmaceutical market can complete the answer from an experienced consumers’ perspective, therefore this study is adopting the questionnaire set methodology to survey among Vitamin C consumer who are experienced with this dietary supplement. Aligning the survey in respect to prior authority research, the measurement items in this survey were adapted from pre-existing scales of operationalization. A questionnaire will be constructed to assess 5 main constructs. They are: 1) Product Country Image 2) Brand Image 3) Expert Opinion 4) Perceived Risk 5) Willingness to buy. These 5 constructs constitute the main proposed conceptual model. All constructs in this questionnaire use a seven-point Likert scale. The research will draw on existing definitions and measures adapted from the consumer behavior and marketing literatures. The theoretical framework and related hypotheses will be tested using primary survey data by using a statistical analysis software package for interpretation and conclusion of findings. Questions for Product Country Image were operationalized and adapted from Roth and Romeo (1992), consisting of four items. Questions such as “How would you rate innovativeness of Cosmeceuticals products from Country of Origin” were specially designed to capture consumers’ perception of products based on their imaginative association of a product to a country. Brand Image, comprising of five items, is borrowed from Robert (2004) and Cho (2011) which are semantically designed to capture meaningfulness of brand perception to the end user. An example of a question is: “The brand adds value to my life”. Four items are asked in the Expert Opinion segment in order to analyze the pedagogical impact of experts’ persuasiveness, operationalized from Aquevegue (2006), such as “The opinion of the experts about the product is (very good to very bad)”. Perceived risk, being measured by 5 statements such as “You want to enjoy better health” in the degree of respondents’ view is heavily adapted and modified from Chang (2007). This segment is directly engineered to identify and understand expectations associated with products from a consumers’ viewpoint resulting in final purchase action. Such expectations can be understood as benefits or the avoidance of threats that are realized through consumption. Applying the hierarchy of needs model (Maslow 1954) could help to reveal and orchestrate consumers’ purchase motivations resulting in valuable marketing insights. Finally, the construct of Willingness to buy, consisting of five items such as “The likelihood of purchasing Cosmeceuticals is (very low to very high)”, is adapted from Dodds and Monroe (1991). Overall, we expect the results of this project to illuminate our understanding of how perceived risk influences consumer decisions in the dietary supplements market. Specifically the results should shed light on the effect of three key drivers of perceived risk, as well as of a key outcome of perceived risk.
        3,000원
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