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Surface modification strategies for high-dose dry powder inhalers
Park Heejun,Ha Eun-Sol,김민수 한국약제학회 2021 Journal of Pharmaceutical Investigation Vol.51 No.6
Background There is a growing interest in the use of dry powder inhalers (DPIs) for administering high-dose drugs with low potency to the lungs as carrier-free formulations to treat both local pulmonary and systemic diseases. The main purpose of particle engineering and formulation design in the development of high-dose DPIs without carrier is to reduce the cohesive property of the particles and overcome the large inter-particulate interaction while enhancing powder dispersion and lung delivery upon inhalation and maintaining stability without agglomeration during storage. In particular, the cohesive property of high-dose DPIs can induce several physiological and physicochemical problems that must be improved. Area covered This review describes various particle surface modification methods, including sophisticated particle engineering (such as micronization) and formulation techniques, which are utilized to overcome the problems associated with high-dose DPIs. Expert opinion Currently, changing the cohesive property of particles through various micronization processes and improving the surface properties of particles through co-processing with limited excipients have been mainly used as efficient methods for particle surface modification. Using these technological principles, novel approaches have been attempted to develop inhalable drug particles, such as high-dose antibiotics and high-value biopharmaceuticals. The research on high-dose DPIs has expanded widely, and consequently, the drugs that received recent regulatory approvals have been successful based on the research results. Thus, it is expected that the next generation of DPIs will be safer and have higher therapeutic efficacy beyond the limitations of traditional high-dose DPIs.
Heejun Park(박희준),Abdul Rehman(압둘 레만),Changhyeong Lee(이창형),Sung Hun Jin(진성훈),Sungtek Kahng(강승택) 대한전기학회 2019 전기학회논문지 Vol.68 No.2
In this paper, we show a new scheme to tackle the problems of high electromagnetic-coupling, poor impedance-matching. and degraded radiation-characteristics of two RFID tag antennas, when they are located with an extremely short distance. As giving it a variety of tries such as periodic EBG-type structures and notch-making stubs, we can get an optimal device to lower the electromagnetic coupling and to match the input impedance of both of the tag antennas. Even for a UHF-band, the device is very thin less than 1 mm unlike other isolation-enhancers which are thick or multi-layered. The dips in the S11 and S21-curves are generated at the target frequency, which means excellent impedance match and lowered interference for the two tag dipole-antennas. This is helpful to higher thruput in RFID.
( Heejune Park ),( Soonbok Kwon ) 융합연구학회 2019 융합연구학회지 Vol.3 No.2
This study aimed to review currently available research on augmented reality (AR) based speech-language therapy for individuals with communication disorders. AR is generally referred to as a system in which the user has a direct view of their environment and where a specially constructed device allows additional information or graphical elements to be blended with the real environment in the form of an overlay. AR-based speech-language therapy refers to speech-language therapy delivered via computer-simulation technology to improve speech and language abilities for children and adults with communication disorders. In addition, this paper addressed limitations of previous studies and benefits of AR-based speech-language therapy. Recent Findings Recent research reports suggest that AR-based speech-language therapy is a viable option for treating children and adults with speech-language disorders. However, most of the research studies were conducted without a rigorous experimental design. Additionally, the quality of technology is difficult to assess and application to real clinical practice is currently lacking. Future studies should be conducted with a rigorous experimental design and more advanced technology. Summary This paper has reviewed current evidence related to the effectiveness of AR-based speech-language intervention for children and adults with speech-language impairment. This paper discussed limitations of the current research and benefits of AR-based speech-language therapy.
Park, Heejun,Oh, Sojin,Lee, Sujeong,Choi, Sora,Oh, Moonhyun Elsevier 2019 Applied Catalysis B Vol.246 No.-
<P><B>Abstract</B></P> <P>The development of carbon-based oxygen reduction reaction (ORR) catalysts to substitute the expensive and unstable platinum-based ORR catalysts is of great importance for their optimal utilization in energy conversion and storage. Herein, we report the production of highly active carbon-based ORR catalyst from well-designed core–shell type hybrid metal–organic framework (MOF). Cobalt- and nitrogen-codoped porous carbon leaves (Co,N-PCLs) are prepared via a simple one-step pyrolysis of well-designed leaf-shaped core-shell type hybrid MOFs (ZIF-L@ZIF-67, ZIF (zeolitic imidazolate framework) is a subclass of MOF), which contain two different metal ions (Zn<SUP>2+</SUP> in core and Co<SUP>2+</SUP> in shell) and sufficient nitrogen source with a thin flat morphology. The structural and compositional features of resulting Co,N-PCLs are characterized using scanning electron microscopy, transmission electron microscopy, energy-dispersive X-ray spectroscopy, X-ray photoelectron spectroscopy, Raman spectroscopy, and N<SUB>2</SUB> sorption isotherms, and the analyses reveal that they possess the ideal structural and compositional features for ORR, such as numerous carbon nanotubes (CNTs), substantial Co- and N-doping, large surface area, and high pore volume while maintaining the advantageous thin leaf-shape. Owing to such unique structural and compositional features, Co,N-PCLs display much better ORR activity than their counterparts prepared from the parent materials (ZIF-L or ZIF-67). In addition, Co,N-PCL even shows a better electrochemical stability and a better methanol tolerance compared to commercial Pt/C material.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Highly active carbon-based ORR catalyst with Co- and N-codoping (Co,N-PCL) was made from core-shell type hybrid MOF. </LI> <LI> Unique structural and compositional features of Co,N-PCL was found to be ideal for ORR catalyst. </LI> <LI> Co,N-PCL displayed an excellent ORR activity with high positive half-wave potential and four-electron transfer pathway. </LI> <LI> Co,N-PCL displayed a better stability and a better methanol tolerance compared to commercial Pt/C. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>
A QoE Evaluation of Augmented and Virtual Reality Speech and Language Treatment Applications
( Heejune Park ),( Sinwook An ),( Inho Bae ),( Soonbok Kwon ) 융합연구학회 2019 융합연구학회지 Vol.3 No.1
The availability of affordable head-mounted displays has resulted in renewed interest in augmented reality (AR) and virtual reality (VR). This in turn has led to research into users’ perceptions of quality in AR and VR environments. In this paper, the authors report the results of an experimental study that compared the user quality of experience (QoE) of an interactive and immersive speech and language assessment implemented in both AR and VR. To the best of the authors’ knowledge, this is the first work that compares user QoE of VR and AR applications, in particular with a focus on applications in the speech and language domain. Subjective and objective data was captured to assess a user’s QoE. Objective data, such as heart rate and electrodermal activity (EDA) was collected using consumer electronic devices such as the Smartwatch biosensor. Subjective data was captured using a user’s self-reported ratings in a post-test questionnaire. The findings of this study demonstrate similar QoE ratings for both the AR and VR environments. The findings also suggest that users acclimatized to the AR environment more quickly than the VR environment.