• Korean Chemical Engineering Research
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• 제58권3호
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• pp.450-457
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• 2020

선행된 연구에서 Yo-Pro-1의 전달 효율의 경향과 CFP 유전자의 발현 효율의 경향이 큰 차이를 보였지만 이 문제에 대한 원인을 제시할 수 없었다. 따라서 본 연구에서는 형광 염료를 이용하여 DNA에 표지 후 전달 효율을 정량화함으로써 이 문제에 대한 원인을 찾고자 한다. 표지를 위한 형광 염료로 Yo-Pro-1을 사용하였으며, Yo-Pro-1과 표지 된 DNA의 전달 효율을 비교하였다. 전압 조건에 따른 전달효율 비교에서는 Yo-Pro-1과 Yo-Pro-1으로 표지 된 DNA의 전달 효율 모두 96 V에서 전달 효율이 최대가 되었으며 전압이 더 증가하면 전달 효율이 오히려 감소하는 경향을 보였다. 전압 인가 횟수 조건에 따른 전달 효율 비교에서는 Yo-Pro-1과 Yo-Pro-1으로 표지 된 DNA의 두 전달 물질 모두 8회의 전압 인가 횟수에서 전달 효율이 최대가 되었으며 전압 인가 횟수가 더 증가하면 전달 효율이 감소하는 경향을 보였다. 두 결과를 통해 디지털 전기천공시스템에서 Yo-Pro-1을 사용한 전달 효율 측정이 DNA의 전달 효율을 잘 대변하는 것을 확인하였다. 또한, 본 연구의 결과를 통해 선행된 연구에서 보인 Yo-Pro-1의 전달 효율의 경향과 CFP 유전자의 발현 효율의 경향 차이는 전달 물질의 전달 효율 차이에서 기인한 결과가 아닌 전달 된 유전 물질의 발현 과정에서의 문제로 인한 결과임을 추론해 볼 수 있었다.

• Industrial Engineering and Management Systems
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• 제11권3호
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• pp.224-232
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• 2012

The paper proposes a non-parametric methodology, data envelopment analysis, for measuring efficiency and productivity in service delivery systems with capacity constraints. The methodology provides allocation approaches for studying behaviors of firm and customers in service delivery strategy. The experimental study is carried out to investigate allocation behaviors and conduct an objective tradeoff between efficiency approach and productivity approach. The experimental result indicates that the efficiency approach allocates resource via maximizing customer efficiency rather than firm productivity as in the productivity approach. Moreover, the experiment reveals that there exists an objective tradeoff between the efficiency approach and the productivity approach. These findings provide strategic options for allocation policy in service delivery systems.

• 산경연구논집
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• 제9권3호
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• pp.7-17
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• 2018

Purpose - The purpose of this paper is to improve last mile delivery capability and ensure customers' satisfaction by approaching an analytic hierarchy process(AHP) and identifying criteria framework to determine locations of last mile delivery centre(LMDC). Research design, data, and methodology - Traffic congestion and emission policy in cities are barriers of last mile delivery in dense areas. The urban consolidation centre(UCC) cannot increase last mile delivery efficiency in dense cities because of their space and traffic limitation. In this paper, we develop a case to improve last mile delivery efficiency and to ensure customers' satisfaction by concentrating on LMDC. In addition, AHP has been applied to identify criteria framework and determine LMDC locations. The weighted priorities are derived from parcel delivery industry experts and have been calculated using Expert Choice software. Results - The framework criteria have assisted decision makers to place LMDC in a dense area to enhance customer's satisfaction with last mile delivery service. Conclusions - AHP has provided ranking framework criteria of LMDC potential for parcel delivery industry. The LMDC helps by improving last mile delivery efficiency to final destination amids conditions of CO₂ emissions, traffic congestion, and pollution problems. It especially concerns delivery service activities when delivering parcels to customers rather than UCC.

• 한국시스템다이내믹스연구
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• 제12권1호
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• pp.89-114
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• 2011

With steady increase in the demand for door-to-door delivery services, courier service providers are facing a constant pressure to reduce delivery price in order to secure quantity order and to improve the efficiency and reliability for customer service. The objective of this research is to explain the structure of the door-to-door delivery including door-to-door delivery service demand, sorting capacity in the hub-terminal, and the system performance measures such as service reliability networks using causal loop diagram(CLD). Based on causal relation, this research describes a comprehensive approach to examine how capacity reliability contributes to the renewal of the firm's competences through its reciprocal relationship with travel time reliability and connectivity reliability. Also, this research suggests the policy alternatives to improve effectiveness and efficiency of door-to-door delivery network in response to increase customer satisfaction and profit maximization of the courier service providers: operational, tactical, and strategic levels.

• 유통과학연구
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• 제14권3호
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• pp.73-83
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• 2016

Purpose - The parcel delivery service(courier) industry all over the world has been expanding its market so far, but its growth has been declining in recent years. In this situation, most parcel delivery companies are having trouble with managing themselves because of the pressure from the customer to increase service level and decrease the rate. The purpose of this study is to provide ways to improve competitive advantages of the parcel delivery service industry by evaluating the multi-period operating efficiency of Korea, Japan and global service providers. Research design, data, and methodology - The data for the period of 2011 to 2014 were collected from the annual reports published by parcel delivery companies. In this study, we analyze the marketability (revenue), profitability (operating profits), and management conditions (net profits) of parcel service companies by combining information on human resources (number of employees) and material resources (total assets and equity). Therefore, the number of employees, total assets, and equity are selected as input variables, and revenue, operating profits, and net profits as the output variables. In this study, DEA (Data Envelopment Analysis) is used to measure the comparative efficiency and MPI (Malmquist Productivity Index) is used to analyze the trend of change of the efficiency for a multi-year period. Results - The operational efficiency scores of medium-sized parcel delivery companies in Korea are higher than other larger competitors such as Korean, Japan and Global larger companies. As of 2014, Logen(1.878) was found to be the most efficient parcel delivery enterprise, followed by KGB (1.224), and Kyoungdong(1.002). Otherwise, Hanjin(0.235), CJ(0.262), Hyundai Logistics(0.657), DHL(0.611), UPS(0.766), FedEx(0.498), TNT(0.350), Yamato(0.762) and Sagawa(0.520), larger sized companies, were done inefficiently. The productivity of parcel delivery companies is influenced by endogenous factors as well as exogenous ones such as changes in business environment and technological advances. Conclusions - Korean medium-sized companies have relatively high efficiency scores in operation. That is why they still survive the competitive market in Korea where market restructuring on the industry has been expected to be conducted for many years. The reason why medium-sized couriers had higher efficient scores than larger couriers is that most of couriers spend more operating expenses versus unit price of delivery which is the amount of money that is needed in order to send a package by parcel service. So the delivery unit price must be taken into account by all the expenses associated with the cost of fuel, labor and maintenance expenses for facilities, etc. therefore, the unit price must be increased to strengthen business competitive power. In order for the industry to have more competitive advantage, the companies need to make profits by increasing demand volume and raising the delivery rate to provide high-quality delivery service to customers. And both endogenous and exogenous change must take precedence in order to strengthen their competitiveness.

• 유통과학연구
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• 제20권9호
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• pp.97-107
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• 2022

Purpose: Online-To-Offline Food Delivery Services (O2O-FDS) is a new element in hotel supply chain that digitalizes traditional food delivery practices using new technologies. Targeting hotel guests, the present research is to explore the role of trust in the relationship between food delivery app on loyalty, price efficiency, and convenience. This new perspective is an essential value addition in the field of hotel marketing in relation to O2O-FDS. Research design, data and methodology: The present research conducted the mediator variable regression analysis as a main statistical methodology to identify the connections between three main constructs using total 244 South Korean participants that were recruited from the professional research company in Korea. Results: The statistical findings based on three steps of mediator regression approach strongly indicate that the trust of food delivery app in the hotel sector plays a moderating role in the relationship between price efficiency and convenience of food delivery app and customer loyalty of food delivery app in the hotel business. Conclusions: This research concludes that hotel practitioners must strive to provide adequate information on food delivery applications in order to increase price efficiency and convenience relative to traditional food and beverage services, influencing consumer trust in food delivery technology.

• 대한의생명과학회지
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• 제29권4호
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• pp.231-241
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• 2023

Messenger RNA (mRNA)-based vaccines and treatments have recently emerged as a promising strategy. Naked mRNA presents various limitations for direct delivery. Therefore, in this paper, Lipid Nanoparticles (LNPs) were utilized for the delivery of mRNA. Lipid nanoparticle (LNP) mRNA systems are highly effective as vaccines, but their efficacy for pulmonary delivery has not yet been fully established. Additionally, research on effective delivery systems and administration methods for vaccines is required to resolve the stability and degradation issues associated with naked mRNA delivery. This study aimed to determine mRNA delivery efficiency via the inhalation of a lipid nanoparticle (LNP) formulation designed specifically for pulmonary delivery. To this purpose, we built a library of seven LNP configurations with different lipid molar and N/P ratios and evaluated their encapsulation efficiency using gel retardation assay. Among the tested LNPs, LNP1, LNP2-2, and LNP3-2 demonstrated high transfection efficiency in vitro based on FACS analyses luciferase assays, and intracellular accumulation tests. The mRNA delivery efficiencies of the selected LNPs after inhalation and intravenous injection were compared and evaluated. LNP2-2 showed the highest mRNA expression in healthy mouse lungs when aerosolized and was found to be non-toxic. These results indicate that LNP2-2 is a promising carrier for lung mRNA delivery via inhalation.

• Journal of Pharmaceutical Investigation
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• 제35권5호
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• pp.343-348
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• 2005

Recently, siRNA has been emerging as new therapeutic agents for various diseases such as cancers and infectious diseases. However, the evaluation for delivery systems for siRNA has not been fully done. In this study, we designed and delivered siRNA of oncogenic E6 and E7 proteins to several cell lines and tested the delivery efficiencies of various cationic nonviral delivery vectors. Of cationic delivery systems tested in this study, lipid-based Lipofectamine revealed higher delivery efficiency of siRNA to cervical cancer cell line, SiHa, compared to other delivery systems. Notably, the polyethylenimine, which showed the comparable delivery efficiencies in plasmid DNA, did not show significant delivery of siRNA in cervical cancer cells. These results indicate that the mechanisms involved in siRNA delivery might be different from those in plasmid DNA delivery, and that cationic lipid-based delivery vehicles deliver siRNA with higher efficiency to intracellular target sites.

• Journal of Microbiology and Biotechnology
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• 제15권2호
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• pp.451-454
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• 2005

Introduction of foreign genes into brain cells, such as neurons and astrocytes, is a powerful approach to study the gene function and regulation in the neuroscience field. Calcium phosphate precipitates have been shown to cause cytotoxicity in some mammalian cells and brain cells, thus leading to low transfection efficiency. Here, we describe a retrovirus-mediated gene delivery method to transduce foreign genes into brain cells. In an attempt to achieve higher gene delivery efficiency in these cells, we made several changes to the original method, including (1) use of a new packaging cell line, Phoenix ampho cells, (2) transfection of pMX retroviral DNA, (3) inclusion of 25 mM chloroquine in the transduction, and (4) 3- 5 h incubation of retroviruses with target cells. The results showed that the modified protocol resulted in a range of 40- 60% gene delivery efficiency in neurons and astrocytes. Furthermore, these results suggest the potential of the retrovirus-mediated gene delivery protocol being modified and adapted for other transfection-refractory cell lines and primary cells.

• Archives of Pharmacal Research
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• 제24권1호
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• pp.1-15
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• 2001

Gene therapy has emerged as a new concept of therapeutic strategies to treat diseases which do not respond to the conventional therapies. The principle of gene therapy is to Introduce genetic materials into patient cells to produce therapeutic proteins in these cells. Gene therapy is now at the stage where a number of clinical trials have been carried out to patients with gene-deficiency disease or cancer. Genetic materials for gene therapy are generally composed of gene expression system and gene delivery system. For the clinical application of gene therapy in a way which conventional drugs are used, researches have been focused on the design of gene delivery system which can offer high transfection efficiency with minimal toxicity. Currently, viral delivery systems generally provide higher transfection efficiency compared with non-viral delivery systems while non-viral delivery systems are less toxic, less immunogenic and manufacturable in large scale compared with viral systems. Recently, novel strategies towards the design of new non-viral delivery system, combination of viral and non-viral delivery systems and targeted delivery system have been extensively studied. The continued effort in this area will lead us to develop gene medicine as "gene as a drug" in the near future.