Effect of chitosan on physicochemical properties of exenatide-loaded PLGA nanoparticles

박민호,백종섭,이초아,조정원 한국약제학회 2013 Journal of Pharmaceutical Investigation Vol.43 No.6

The aim of this study was to test stability of exenatide and compare physicochemical properties of PLGA nanoparticles. To make small, stable, uniform and highly encapsulated nanoparticles, various factors such as the components (polymer and stabilizer) and preparation condition (organic phase, temperature or sonication time)were considered. We tested the effect of organic phase,acid/base, ultrasonication time or temperature on exenatide to decide preparation condition of PLGA nanoparticles. And, PLGA nanoparticles were prepared by the double emulsion-solvent evaporation method and chitosan was selected as stabilizer. PLGA nanoparticles were characterized by yield, encapsulation efficiency, drug loading,particle size, zeta potential, polydispersity index and morphology. In this study, PLGA nanoparticles showed different physicochemical properties according to chitosan molecular weight. In case of particle size, PLGA nanoparticles using 0.5 g chitosan (4 kDa) showed biggest particle size (781.4 ± 24.1 nm) among PLGA nanoparticles prepared in this study and PLGA nanoparticles using 1 g chitosan (2 kDa) showed highest encapsulation efficiency (52.8 ± 1.7 %) among PLGA nanoparticles prepared in this study. And, all of PLGA nanoparticles using chitosan showed that polydispersity index was low and zeta-potential was increased. These results suggest that chitosan molecular weight affects physicochemical properties of PLGA nanoparticle.

고속도로 교통사고에 대한 기하구조의 영향(한계효과)에 관한 연구

박민호 대한교통학회 2014 대한교통학회지 Vol.32 No.1

이 연구는 고속도로에서 발생한 교통사고에 대한 기하구조의 영향을 알아보고자 시도되었다. 기하구조의 경우에 는 지침 등에서 정하는 기준 권장값등이 있지만, 기존의 사고모형에서는 교통사고에 영향을 미치는 기하구조의 자료가 통합된 형태로 사용되어 혼합된 형태로 설치된 현실을 추정된 모형이 제대로 설명하지 못하는 단점이 있다. 따라서 이 연구에서는 기하구조를 기준값에 의해 세분화된 기하구조 자료를 사용함으로써, 현실을 반영한 모형을 추출하고자 하였다. 그리고 각 기하구조별 탄력성 분석을 통해 사고에 미치는 영향을 제시하였다. 이는 향후 교통안전을 고려한 기하구조의 지침 정립에 도움이 될 것으로 사료된다. This study dealt with the impacts of geometric structure on traffic accidents occurring on the interstates. There are standard values for the case of geometric structure which are recommended in the design guideline/policy; however, in the previous models, geometric variables were adapted as integrated ones as opposed to mixed ones in the real world so that derived models had a weakness to reflect the real. Therefore, using subdivided geometric variables, this study tried to derive the model which reflects the real world. In addition, by calculating elasticity, each variables' effect to the accidents are estimated. Hopefully, this study will help to establish the future guideline/policy of geometrics considering traffic safety.

Random Parameters 음이항 모형을 이용한 신호교차로 교통사고 모형개발에 관한 연구 -대전광역시를 대상으로 -

박민호,홍정열 한국도로학회 2018 한국도로학회논문집 Vol.20 No.2

PURPOSES: The purpose of this study is to develop a crash prediction model at signalized intersections, which can capture the randomness and uncertainty of traffic accident forecasting in order to provide more precise results. METHODS: The authors propose a random parameter (RP) approach to overcome the limitation of the Count model that cannot consider the heterogeneity of the assigned locations or road sections. For the model’s development, 55 intersections located in the Daejeon metropolitan area were selected as the scope of the study, and panel data such as the number of crashes, traffic volume, and intersection geometry at each intersection were collected for the analysis. RESULTS: Based on the results of the RP negative binomial crash prediction model developed in this study, it was found that the independent variables such as the log form of average annual traffic volume, presence or absence of left-turn lanes on major roads, presence or absence of right-turn lanes on minor roads, and the number of crosswalks were statistically significant random parameters, and this showed that the variables have a heterogeneous influence on individual intersections. CONCLUSIONS : It was found that the RP model had a better fit to the data than the fixed parameters (FP) model since the RP model reflects the heterogeneity of the individual observations and captures the inconsistent and biased effects.

Sonographic Findings of Common Musculoskeletal Diseases in Patients with Diabetes Mellitus

박민호,박지선,안성은,류경남,박소영,진욱 대한영상의학회 2016 Korean Journal of Radiology Vol.17 No.2

Diabetes mellitus (DM) can accompany many musculoskeletal (MSK) diseases. It is difficult to distinguish the DM-related MSK diseases based on clinical symptoms alone. Sonography is frequently used as a first imaging study for these MSK symptoms and is helpful to differentiate the various DM-related MSK diseases. This pictorial essay focuses on sonographic findings of various MSK diseases that can occur in diabetic patients.

Effects of Long-Distance Running on Cardiac Markers and Biomarkers in Exercise-Induced Hypertension Runners: An Observational Study

박민호,신경아,김철현,이윤희,박용범,안재기,김영주 대한재활의학회 2018 Annals of Rehabilitation Medicine Vol.42 No.4

Objective To investigate changes of cardiac and muscle damage markers in exercise-induced hypertension (EIH) runners before running (pre-race), immediately after completing a 100-km ultramarathon race, and during the recovery period (24, 72, and 120 hours post-race).Methods In this observational study, volunteers were divided into EIH group (n=11) whose maximum systolic blood pressure was ≥210 mmHg in graded exercise testing and normal exercise blood pressure response (NEBPR) group (n=11). Their blood samples were collected at pre-race, immediately after race, and at 24, 72, and 120 hours post-race.Results Creatine kinase (CK) and cardiac troponin I (cTnI) levels were significantly higher in EIH group than those in the NEBPR group immediately after race and at 24 hours post-race (all p<0.05). However, lactate dehydrogenase (LDH), creatine kinase-myocardial band (CKMB), or CKMB/CK levels did not show any significant differences between the two groups in each period. N-terminal pro-brain natriuretic peptide (NT-proBNP) levels were significantly higher in EIH group than those in NEBPR group immediately after race and at 24 and 72 hours post-race (all p<0.05). A high sensitivity C-reactive protein (hs-CRP) level was significantly higher in EIH group than that in NEBPR group at 24 hours post-race (p<0.05).Conclusion The phenomenon of higher inflammatory and cardiac marker levels in EIH group may exaggerate cardiac volume pressure and blood flow restrictions which in turn can result in cardiac muscle damage. Further prospective studies are needed to investigate the chronic effect of such phenomenon on the cardiovascular system in EIH runners.

방폭화조 전기기기에 대한 법적 형식검정제도도입에 관한 연구(2)

박민호,원중수 대한전기협회 1985 대한전기협회지 Vol.- No.97

LQ 제어로 조단블록이 있는 중근을 실근으로 이동시키는 가중행렬 결정 방법

박민호 한국산학기술학회 2020 한국산학기술학회논문지 Vol.21 No.6

In general, the stability and response characteristics of the system can be improved by changing the pole position because a nonlinear system can be linearized by the product of a 1st and 2nd order system. Therefore, a controller that moves the pole can be designed in various ways. Among the other methods, LQ control ensures the stability of the system. On the other hand, it is difficult to specify the location of the pole arbitrarily because the desired response characteristic is obtained by selecting the weighting matrix by trial and error. This paper evaluated a method of selecting a weighting matrix of LQ control that moves multiple double poles with Jordan blocks to real poles. The relational equation between the double poles and weighting matrices were derived from the characteristic equation of the Hamiltonian system with a diagonal control weighting matrix and a state weighting matrix represented by two variables (, ). The Moving-Range was obtained under the condition that the state-weighting matrix becomes a positive semi-definite matrix. This paper proposes a method of selecting poles in this range and calculating the weighting matrices by the relational equation. Numerical examples are presented to show the usefulness of the proposed method. 일반적으로 비선형 시스템은 1차와 2차 시스템의 곱으로 선형화할 수 있기 때문에 시스템은 2차 시스템의 중근, 복소근, 서로 다른 두 실근과 1차 시스템의 근을 극점으로 가진다. 이런 극점의 위치 변경으로 시스템의 안정성과 응답특성을 개선할 수 있어서 다양한 방법으로 극점을 이동시키는 제어기를 설계한다. 여러 방법 중에서 LQ 제어는 이득여유와 위상여유의 안정성을 보장한다. 그런데 시행착오 방법으로 가중행렬을 선택하여 원하는 응답특성을 얻기 때문에 극점의 위치를 임의로 지정하기 어렵다. 이 논문은 조단블록을 가진 다중 중근을 원하는 실근으로 이동시키는 LQ 제어의 가중행렬을 선택하는 방법에 관한 것이다. 대각행렬 형태의 제어가중행렬과 와 의 2개 변수 상태가중행렬을 갖는 해밀토니안 시스템의 특성방정식에서 중근과 가중행렬의 관계식을 유도한다. 그리고 상태가중행렬이 양의 준정부호 행렬이 될 조건에서 실근으로 이동할 중근의 이동범위를 구하고, 좌표평면에 표현한다. 이 범위에서 극점을 선택하고, 관계식으로 가중행렬을 계산하는 방법을 제안한다. 그리고 예제를 통해 조단블록을 갖는 4개의 중근을 원하는 서로 다른 실근으로 이동시키는 가중행렬과 제어법칙의 계산과정을 통해 제안한 방법의 유용성을 확인하였다.

스마트 팩토리를 위한 AutoML기반 센서 데이터 이상치 탐지 시스템

박민호,안현철 한국지능정보시스템학회 2020 한국지능정보시스템학회 학술대회논문집 Vol.2020 No.11

LQ 제어와 근의 이동범위를 이용한 중근의 극배치 방법

박민호 한국산학기술학회 2020 한국산학기술학회논문지 Vol.21 No.1

일반적으로 비선형 시스템은 1차와 2차 시스템의 곱의 형태로 선형화되며, 시스템은 실근, 중근, 서로 다른 두 실근, 복소근의 4종류의 근을 가진다. 이 논문은 시스템이 가지는 4가지 근 중에서 조단블록을 갖는 중근을 복소근으로 이동시키는 LQ 제어의 가중행렬과 제어법칙을 설계하는 방법에 관한 것이다. 상태가중행렬을 제한 조건으로 하고 성능지수함수를 최소화하는 LQ 제어는 시스템의 안정성을 보장하고 시스템의 근을 이동시키는 극배치 기능을 가지고 있다. 그렇지만 이 방법은 시행착오 방법으로 설계 변수인 가중행렬을 설정하고, 이동되는 근의 위치를 정확히 지정할 수 없는 문제가 있다. 이 문제를 해결하기 위해 해밀토니안 시스템의 특성방정식을 대각행렬의 제어가중행렬과 삼각함수로 표현된 상태가중행렬을 이용하여 기술한다. 이동할 복소근이 이 특성방정식의 근이라는 조건에서 중근과 상태가중행렬의 관계식(, )을 유도하고 상태가중행렬이 양의 반한정행렬이라는 조건에서 중근의 이동범위를 구하고, 좌표평면에 도시한다. 그려진 중근의 이동범위에서 복소근을 선택하여 관계식에 대입하여 상태가중행렬을 계산하고, 이것에서 제어법칙이 구한다. 예제에서 3차 시스템의 중근을 이동시키는 제어법칙의 설계과정을 통해 제안한 방법의 타당성을 확인하였다. In general, a nonlinear system is linearized in the form of a multiplication of the 1st and 2nd order system. This paper reports a design method of a weighting matrix and control law of LQ control to move the double poles that have a Jordan block to a pair of complex conjugate poles. This method has the advantages of pole placement and the guarantee of stability, but this method cannot position the poles correctly, and the matrix is chosen using a trial and error method. Therefore, a relation function (,) between the poles and the matrix was derived under the condition that the poles are the roots of the characteristic equation of the Hamiltonian system. In addition, the Pole's Moving-range was obtained under the condition that the state weighting matrix becomes a positive semi-definite matrix. This paper presents examples of how the matrix and control law is calculated.

The effect of Eudragit type on BSA-loaded PLGA nanoparticles

박민호,백종섭,이초아,김동철,조정원 한국약제학회 2014 Journal of Pharmaceutical Investigation Vol.44 No.5

Poly(D,L-lactide-co-glycolide) nanoparticle (PLGANP) have been broadly studied as a carrier for drugdelivery system of peptides and proteins. However, negativesurface charge of PLGA NP using only PLGAdecreases bioavailability under oral administration. In thisstudy, novel carriers for oral delivery system through anadditional bioadhesive polymer, Eudragit was introduced. Our purpose is to prepare PLGA NP using bovine serumalbumin (BSA) as a model drug and Eudragit and evaluatetheir physiochemical characteristics, eventually expand topeptide and protein drug such as insulin or exenatide. Inthis study, PLGA NP were spherical and the size wasaround 400–500 nm. The encapsulation efficiency (EE) ofPLGA NP when prepared with only PLGA was the highest,approximately 95.3 %. The polydispersity index valueswere low approximately 0.1, which meant their size wasregular. In mucoadhesion test, we knew PLGA NP preparedby using Eudragit RS or Eudragit RL had a highaffinity to mucin particles through zeta-potential change ofmucin particle to cover their surface. Also, PLGA NP didnot show cytotoxicity against Caco-2 cells. Especially,BSA-loaded PLGA NP using Eudragit RS 100 preparedhad high EE, low polydispersity index, spherical shapehaving a smooth surface, sustained release profile, noncytotoxicityand bioadhesive effect.