• Aerospace Engineering and Technology
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• v.3 no.2
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• pp.217-228
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• 2004

This paper presents the rotating test techniques and the results of the roating test of the small-scaled hingeless rotor system with composite paddle blades in hover and forward flight conditions. The small-scaled rotor system was designed using froude-scaled properties of full scale rotor system. Metal flexures and composite flexures were made as hub flexures by the same dynamic properties of rotor system. The rotating tests of hingeless rotor system installed in GSRTS at KARI were carried out to get lead-lag damping ratios and aerodynamic loads of the hingeless rotor system. MBA(Moving Block Analysis) technique was used for the estimation of lead-lag damping ratio. 6-components balance was installed between hub and main shaft and straingauges on blades were instrumented for the measurements of aerodynamic loads of rotor system. Tests were performed on the ground and in the wind tunnel according to the test conditions of hover and forward flight, respectively.

• Archives of Plastic Surgery
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• v.33 no.3
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• pp.283-288
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• 2006

Various vascularized free flaps have been used for midfacial reconstruction after ablative head and neck cancer surgery. The most common donor sites for free flap include latissimus dorsi, rectus abdominis, and radial forearm. Between 1994 and 2004, 14 patients underwent free flap operation after head and neck cancer ablation, and were reviewed retrospectively. Among 14 free flaps, 8 were latissimus dorsi myocutaneous flaps, 3 rectus abdominis myocutaneous flaps and 3 radial forearm flaps, respectively. The overall survival rate of the flap was 100%. Complications were wound dehiscence(5 cases) and ptosis(1 case). We designed multiple dimensionally folded free flap for midfacial reconstruction. For 3-dimensional flap needs, we used latissimus dorsi myocutaneous flap. 2-Dimensional flap was latissimus dorsi or rectus abdominis myocutaneous flap and 1-dimensional flap was radial forearm flap. In this study we produced an algorithm for midfacial reconstruction. Large volume with many skin paddle defects were best reconstructed with latissimus dorsi myocutaneous flap or rectus abdominis myocutaneous flap. Radial forearm flap was used for reconstruction of small volume and little skin paddle defects.

• Archives of Plastic Surgery
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• v.41 no.4
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• pp.366-373
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• 2014

Background The advent of skin-sparing mastectomy has allowed for the reconstruction of the breast and nipple with improved cosmesis. However, the nipple-areolar complex (NAC) in Asian patients is more pigmented and scars easily. Therefore, commonly described incisions tend to result in poor aesthetic outcomes in Asian patients with breast cancer. Methods We describe an algorithmic approach to skin-sparing mastectomy incisions in Asian patients on the basis of the location of the biopsy scar and the tumor site and size. Four incision types are described: peri-areolar, a peri-areolar incision with a second distant skin paddle, "racquet handle," and peri-areolar with adjacent skin excision. Results 281 immediate breast reconstructions were performed between May 2001 and February 2012 after skin-sparing mastectomy. The mastectomy incisions used included the peri-areolar design (n=124, 44%), peri-areolar design with a second distant skin paddle (n=39, 14%), "racquet handle" (n=21, 7.5%), and peri-areolar design with adjacent skin excision (n=42, 14%). The traditional elliptical incision and other variants where the NAC outline was not preserved were performed in the remaining 55 patients. The average follow-up was 44.7 months during which there was 1 case of total flap loss and 7 cases of partial flap necrosis; all remaining flaps survived. 24% of the patients (68/281) underwent subsequent nipple reconstruction. Conclusions Our algorithm avoids breast incisions that are randomly placed or excessively long and prevents the unnecessary sacrifice of normal breast skin. This allows skin-sparing mastectomy and immediate breast reconstruction to be performed with a consistently achievable aesthetic result in Asian women without neglecting oncological safety.

• Journal of Pharmaceutical Investigation
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• v.28 no.4
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• pp.275-282
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• 1998

In order to develop a desirable in vitro release which correlates well with in vivo bioavailability, hollow type suppository containing Propranolol HCl(PPH) powder in the cavity and conventional type suppository with dispersed PPH in the base were prepared. Polyvinyl alcohol (PVA) hydrogel as a base and PPH as a model drug were used for the preparation of suppository. The rates of drug release from the suppositories were studied by Paddle method, Muranish method, Dialysis tubing method and Rotating dialysis cell method. The release profiles from suppositories using the four different release tests were compared. After a rectal administration in rat, the mean $C_{max}$ of hollow type suppository was significantly lower than that of conventional type, but $T_{max}$, $AUC_{0{\to}12}$ and MRT of hollow type were significantly higher 1.6 times, 1.2 times and 1.9 times than those of conventional type, respectively. The computer program was used to simulate plasma concentration from in vitro released amounts of drug and in vivo pharmacokinetic parameters. Based on comparison of the simulated bioavailability from computer program with experimental bioavailability in rat we have found out in vitro release test which correlates well with in vivo bioavailability. Our results have shown the best correlation between in vitro release and in vivo bioavailability in PPH-PVA hydrogel hollow type suppository for the paddle method and conventional type suppository for the rotating dialysis cell method. In this work we propose that PPH-PVA hydrogel suppository shows in vitro-in vivo correlation. This data should help to optimize the formulation of the drug and provide a basis for quality control procedures.

• YAKHAK HOEJI
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• v.55 no.2
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• pp.131-137
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• 2011

The dissolution test method and an analytical procedure by HPLC were developed and validated for dobesilate calcium tablets and acepifylline tablets. These drugs were not yet characterized by the dissolution specifications in Korean Pharmaceutical Codex. So, with each reference and test drugs, we did the preliminary and standard experiments based on the Korean Pharmacopeia Guideline of dissolution testing for solid oral dosage forms. The dissolution test for dobesilate calcium tablets was carried out under sink conditions as following: dissolution medium water, paddle rotation speed 50 rpm and vessel volume 900 ml. More than 90% of its label amount was released within 30 min in this method. Also the dissolution test for acepifylline tablets was carried out under sink conditions as follows: dissolution medium water, paddle rotation speed 100 rpm and vessel volume 900 ml. More than 90% of its label amount was released within 45 min in this method. The dissolution samples were analyzed with a precise and accurate HPLC method. The developed dissolution test showed specificity, linearity, precision and accuracy within the acceptable range. The dissolution testing method described above was adequate for the purpose and may be proposed as a pharmacopeial standard to assess the performance of dobesilate calcium tablets and acepifylline tablets.

• Journal of the Korean Chemical Society
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• v.60 no.5
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• pp.321-326
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• 2016

Two new polymeric complexes, [Zn(dpa)(pyz)_0.5]_n (1; dpa = diphenate and pyz = pyrazine) and [Mn₃(bpdc)₃(py)₄]_n (2; bpdc = biphenyl-4,4'-dicarboxylate and py = pyridine) were successfully isolated by the hydro- and solvo-thermal technique, respectively. The complexes were characterized by elemental and thermal analysis, vibrational IR spectroscopy, and by single crystal x-ray structure determination. For 2, magnetic property was also investigated. Complex 1 is a two-dimensional layer structure consisting of a paddle-wheel building unit of Zn-dpa chains bridged by pyrazine. While, complex 2 consists of linear trimeric Mn3 cluster as building unit to form 3D network. In the complexes, dpa²⁻ (1) and bpdc²⁻(2) ligands show a typical bis-monodendate bridging and two kinds of bridging modes; a typical bridging and chelating/bridging mode, respectively.

• KSBB Journal
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• v.6 no.3
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• pp.231-240
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• 1991

Recently, developments of large scale and high density cell culture methods have been the objects of many researches, because the demand of various pharmaceutical products produced by animal cell culture has been rapidly increasing. The cell culture equipment should have the requirements such as sufficient oxygen transfer and mixing, low shear stress and surface tension, and small foaming. In order to develop a proper bioreactor meeting these requirements simultaneously, a perfluorocarbon having high solubility of oxygen was sprayed into the medium as an oxygen carrier instead of air. Also, a new impeller was developed and combined together with the perfluorocarbon spraying system so as to design a new bioreartor for cell cultivation. The new impeller had better characteristics of mixing and oxygen transfer than the paddle and cell-lift impellers based on the same, shear rate. But, it was observed that the volumetric oxygen transfer coefficient of the new bioreactor decreased with increasing cell density during E. coli fermentation.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.619-622
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• 2005

Purpose of this study is to investigate the size-dependent mechanical properties in micron scale medium. Theories such as the couple stress theory and strain gradient theory explain that the deformation in the micron scale is dependent upon the size of the medium. Specimens of the cantilever type, bridge type and paddle type beam that have thickness of 900, 1000 and 1200 nm and width of 10, 20, 30 and $50{\mu}m$ were fabricated by the MEMS technique. We carried out the bending and torsion test to measure the mechanical properties such as the young's modulus, yield strength and torsional rigidity using the AFM(Atomic Force Microscopy).

• Proceedings of the Korean Society of Applied Pharmacology
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• 1997.04a
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• pp.118-118
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• 1997

Solid dispersions were used to increase the dissolution rate of biphenyl dimethyl dicarboxylate (DDB) in water, with the ultimate goal of optimizing its bioavailability when incoporated into pharmaceuticals. Carriers used were Kollidon 30, Kollidon VA 64, 2-hydroxypropyl-${\beta}$-cyclodextrin (HPCD), sodium salicylate or sodium benzoate. DDB solid dispersions were prepared at drug to carrier proportions ranging from 1 : 5 to 1 : 20 (w/w) by solvent evaporation method. DDB tablets (7.5 mg) were prepared by compressing the powder mixture composed of solid dispersions, lactose, corn starch, crospovidone and magnesium stearate using a single-punch press. DDB capsules (7.5 mg) were prepared by filing the mixture into empty hard gelatin capsules (size #1). Dissolution studies of DDB from powdered solid dispersions, tablets and capsules were performed in 900 $m\ell$ of water at 100 rpm and 37$^{\circ}C$ by the paddle method. The dissolved amount was assayed by HPLC and expressed as the mean(%)of three determinations.

• Journal of Pharmaceutical Investigation
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• v.32 no.2
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• pp.95-101
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• 2002

Matrix tablets of nifedipine (NP) were prepared with Eudragit, diluent (lactose or Ca. phosphate) and Mg. stearate employing two different preparation methods (wet granulation and direct compression) to develop its sustained-release dosage forms. The effects of various formulation factors on the dissolution rate of the drug were investigated. Dissolution test was studied in pH 6.8 phosphate buffer containing 1% sodium lauryl sulfate using the paddle method. Formulation factors were the type and content of Eudragit, the type of diluent and the tablet preparation method. The optimum formula of NP matrix tablet, which resulted in a similar dissolution profile to that from Adalat Oros used as a reference, was 30 mg NP, 10% Eudragit RS, 2% Mg. stearate and an adequate quantity of lactose to yield 500 mg weight using the wet granulation method.