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Jung Woo Lee

Publications and source records attributed to Jung Woo Lee.

14 recordsLinked to original sources
PubMed2007

A color version of the Hinsberg test: 1 degrees -3 degrees amine indicator.

The Hinsberg test to recognize the type of amine (1 degrees -3 degrees amines), which has been established for more than 100 years and well documented in textbooks, is not possible without conducting complicated organic reactions. We report for the first time unique chemosensors that are capable of showing selective color changes toward 1 degrees -3 degrees amines as a color version of the Hinsberg test. This simple and straightforward qualitative analysis, using the synthesized novel compounds herein, can be considered a new innovative tool for discriminating 1 degrees -3 degrees amines as an alternative to the historical Hinsberg test.

Amines↗
PubMed2006

Development of acetylated HDD kit for preparation of 188Re-HDD/lipiodol.

A lipiodol solution of (188)Re-4-hexadecyl-2,2,9,9-tetramethyl-4,7-diaza-1,10-decanedithiol ((188)Re-HDD/lipiodol) is in clinical study for liver cancer therapy. However, formulation of it is difficult due to highly active and unstable sulfhydryl groups. We produced new kits using diacetylated HDD (AHDD), in which sulfhydryl groups are protected. We found that AHDD kit can replace HDD kit due to an increased stability for formulation, the better radiolabeling efficiency (78%) and the equivalent biodistribution pattern in mice.

Acetylation↗
PubMed2006

Interaction of a transition metal atom with intrinsic defects in single-walled carbon nanotubes.

Interaction of a transition metal atom with defects in single-walled carbon nanotubes (SWNTs) were investigated through density functional theory calculations. For three kinds of intrinsic defects (single vacancies, double vacancies and Stone-Wales defects) in (5,5) armchair and (10,0) zigzag SWNTs, stable configurations were analyzed. The orientation of the specific bonds of the defects is related to the most stable configuration among several possible configurations. The stable adsorption sites and binding energies of a Ni atom on three intrinsic defects were calculated and compared to those on perfect side walls. All defects enhance Ni adsorption, and the single vacancy shows the most exothermic binding. These results shed light on the nature of the interaction of the transition metal with defects in SWNT, an important topic to the many aspects of carbon nanotubes interacting with transition metals. Particularly, this is useful for the fabrication of nanosized transition metal particles supported on carbon nanotubes.

Journal Article↗
PubMed2005

Diffusion in three-dimensionally ordered scaffolds with inverted colloidal crystal geometry.

Inverted colloidal crystal geometry has been recently utilized in the design of highly organized 3D cell scaffolds. The regularity of the resulting scaffolds enables computational modeling of scaffold properties. In this work we probe the resistance offered by these scaffolds to nutrient transport, by using Brownian dynamics and Monte Carlo simulations to model the effective nutrient diffusivity. Brownian dynamics simulations indicate that the effective diffusivity for small nutrients in the scaffold, D(eff)=0.3D(0), where D(0) is the free solution diffusivity. Further, results of Monte Carlo simulations for dilute solutions of larger particles show that the D(eff) decreases linearly with the size of the particles.

Biocompatible Materials↗
PubMed2004

Highly effective fluorescent sensor for H2PO4(-).

A new anthracene dimer connected by two imidazolium moieties has been systematically designed and synthesized as a fluorescent chemosensor for selective binding of H(2)PO(4)(-) over other anions, which have been examined using fluorescence and (1)H NMR and rationalized with ab initio study.

Journal Article↗
PubMed2003

New fluorescent photoinduced electron transfer chemosensor for the recognition of H2PO4-.

[structure: see text] The fluorescent chemosensor 1 bearing two imidazolium groups at the 1,8-position of anthracene has been designed for the recognition of anions through the (C-H)(+)- - -X(-) hydrogen bond formation. As unique tweezer-like binding of 1 with anions is predicted by the ab initio calculations, strong anion-binding properties of chemosensor 1 are demonstrated by using fluorescence as well as (1)H NMR.

Journal Article↗
PubMed2003

Molecular recognition of fluoride anion: benzene-based tripodal imidazolium receptor.

A benzene-based tripodal imidazolium receptor utilizing the strong (C-H)(+)...X(-) hydrogen bonding interaction between imidazolium moieties and halide anions is extensively investigated both theoretically and experimentally. Ab initio calculations predict that this receptor has a very high affinity for fluoride ion (F(-)). The association constant and free energy gain of the N-butyl receptor 2 for F(-) in acetonitrile were measured to be 2.1 x 10(5) M(-1) and -7.25 kcal/mol, respectively, showing that the receptor has a high affinity for F(-) in highly polar organic solvents.

Journal Article↗
PubMed2002

Assembling phenomena of calix[4]hydroquinone nanotube bundles by one-dimensional short hydrogen bonding and displaced pi-pi stacking.

Using the computer-aided molecular design approach, we recently reported the synthesis of calix[4]hydroquinone (CHQ) nanotube arrays self-assembled with infinitely long one-dimensional (1-D) short hydrogen bonds (H-bonds) and aromatic-aromatic interactions. Here, we assess various calculation methods employed for both the design of the CHQ nanotubes and the study of their assembly process. Our calculations include ab initio and density functional theories and first principles calculations using ultrasoft pseudopotential plane wave methods. The assembly phenomena predicted prior to the synthesis of the nanotubes and details of the refined structure and electronic properties obtained after the experimental characterization of the nanotube crystal are reported. For better characterization of intriguing 1-D short H-bonds and exemplary displaced pi-pi stacks, the X-ray structures have been further refined with samples grown in different solvent conditions. Since X-ray structures do not contain the positions of H atoms, it is necessary to analyze the system using quantum theoretical calculations. The competition between H-bonding and displaced pi-pi stacking in the assembling process has been clarified. The IR spectroscopic features and NMR chemical shifts of 1-D short H-bonds have been investigated both experimentally and theoretically. The dissection of the two most important interaction components leading to self-assembly processes would help design new functional materials and nanomaterials.

Calixarenes↗
PubMed2002

An electrochemically controllable nanomechanical molecular system utilizing edge-to-face and face-to-face aromatic interactions.

[formula: see text] A new molecular system, 2,11-dithio[4,4]metametaquinocyclophane containing a quinone moiety, was designed and synthesized. As the quinone moiety can readily be converted into an aromatic pi-system (hydroquinone) upon reduction, the nanomechanical molecular cyclophane system exhibits a large flapping motion like a molecular flipper from the electrochemical redox process. The conformational changes upon reduction and oxidation are caused by changes of nonbonding interaction forces (devoid of bond formation/breaking) from the edge-to-face to face-to-face aromatic interactions and vice versa, respectively.

Journal Article↗
PubMed1972

The Prevalence Of Intestinal Helminthes In Inhabitants Of Cheju Do.

The authors examined 3,169 fecal specimens from inhabitants of seven localities such as City, Eups and Myons in Cheju Do on July 1970 with cellophane thick smear technique. The results were analysed and summarized as follows: 1) The overall egg positive rate of helminths was 82.2% and it was attributed to high rates of soil-transmitted helminths as in case of other parts in Korea. 2) The infection rates of each species were; A. lumbricoides 44.3%, T. trichiurus 65.6%, hookworm 1.5%, T. orientalis 0.8%, C. sinensis 0.2%, P. westermani 0.4%, M. yokogawai 0.9%, Taenia sp. 12.7% and H. nana 1.4%. 3) The infection rates of soil-transmitted helminths were relatively lower than those of mainland Korea especially in case of hookworm and T. orientalis. The proportion of unfertilized ova passers among the Ascaris infected case was 22.1%. 4) The ova of heterophyids, most probably Metagonimus yokogawai were detected in lower percentage but discovered throughout the localities surveyed and in all age groups. It is certainly presumed that Metagonimus infection is autochthonous. 5) The most interesting results were obtained in Taenia sp. infection and the higher rates were shown in rural area than in urbanized areas. The positive rates were within 5% in childhood and adolescence but abruptly increased up to 36.4 % in adults.

Journal Article↗
PubMed1972

Santonin-Kainic Acid Complex As A Mass Chemotherapeutic Of Ascaris Lumbricoides Control In Korea.

Santonin-kainic acid complex was evaluated as a chemotherapeutic of the mass treatment of the Ascaris lumbricoides infection in Korea. The results could be summarized as follows: 1) The negative conversion rate was 82.9% in average in 4 treated groups. Some variations of negative conversion rate among the treated groups were noticed. 2) The egg reduciton rate was 97.7% in average and the results were rather uniform among the three evaluated groups. 3) By the analysis of egg reduction, it seems that the lightly infected cases whose E.P.G. were under 5,000 were resistant to treatment with the less reduced egg output. 4) After the treatment with this complex, the number of egg discharged cases were reduced to 1.84% and the average number of discharge eggs per incompletely treated or untreated cases were reduced to 12.5% compared with the level of before-treatment egg output. 5) The successive observations of the pattern of worm expulsion after drug intake was made. The worms were mostly expelled in the stool within 3 days, and 58.9% of total expelled worms were collected within 24-hour stool. 6) The minimum length of the immature worms expelled was 7.6cm. Among the 659 Ascaris collected in the first-day stool from 91 rural people, 8.5% were in the range of 7.6-12.2 cm-long, immature worms. The sex ratio, male: female= 0.69: 1.

Journal Article↗
PubMedDate not supplied

Regeneration of hyaline articular cartilage with irradiated transforming growth factor beta1-producing fibroblasts.

The regeneration of hyaline articular cartilage by cell-mediated gene therapy using transforming growth factor beta(1) (TGF-beta(1))-producing fibroblasts (NIH 3T3-TGF-beta(1)) has been reported previously. In this study, we investigated whether TGF-beta(1)-producing fibroblasts irradiated with a lethal dose of radiation are still capable of inducing the regeneration of hyaline articular cartilage. NIH 3T3TGF-beta(1) fibroblasts were exposed to doses of 20, 40, or 80 Gy, using a irradiator, and then injected into artificially made partial defects on the femoral condyle of rabbit knee joints. The rabbits were killed 3 or 6 weeks postinjection and hyaline articular cartilage regeneration was evaluated by histological and immunohistochemical staining (n = 5 per each group). Irradiated NIH 3T3-TGFbeta(1) fibroblasts started to die rapidly 3 days after irradiation; moreover, the kinetics of their viability were similar regardless of the radiation intensity. TGF-beta1 expression, measured by ELISA, showed that the TGF-beta(1) protein produced from the irradiated cells peaked 5 days after irradiation and thereafter declined rapidly. Complete filling of the defect with reparative tissue occurred in all the groups, although variations were observed in terms of the nature of the repair tissue. Histological and immunohistochemical staining of the repair tissue showed that the tissue newly formed by irradiated NIH 3T3-TGF-beta(1) fibroblasts after exposure to 20 Gy had hyaline cartilage-like characteristics, as was observed in the nonirradiated controls. On the other hand, the repair tissue formed by NIH 3T3-TGF-beta(1) fibroblasts irradiated with 40 or 80 Gy showed more fibrous cartilage-like tissue. These results suggest that TGF-beta(1)-producing fibroblasts irradiated up to a certain level of lethal dose (i.e., 20 Gy) are able to induce normal-appearing articular cartilage in vivo. Therefore, irradiated heterologous cell-mediated TGF-beta(1) gene therapy may be clinically useful and an efficient method of regenerating hyaline articular cartilage.

3T3 Cells↗
PubMedDate not supplied

Usefulness of diffusion tensor imaging for evaluation of motor function in patients with traumatic brain injury: three case studies.

OBJECTIVES: To determine whether diffusion tensor imaging (DTI) can detect diffuse axonal injury, and to evaluate the association of DTI findings with motor function in patients with traumatic brain injury. DESIGN: Three case studies. SETTING: An inpatient rehabilitation unit in Korea. PARTICIPANTS: Three patients with traumatic brain injury in whom conventional neuroimaging showed normal-appearing white matter. MAIN OUTCOME MEASURES: Patients were studied with DTI. Fractional anisotropy (FA) was measured from 3 different anatomic locations on both sides of the corticospinal tract. Motor function was evaluated using the motoricity index. RESULTS: Fractional anisotropy tended to be reduced in normal-appearing corticospinal tracts that were remote from the involved segment. Diffusion tensor imaging showed reduction of FA in areas consistent with motor dysfunction. CONCLUSION: Fractional anisotropy of the corticospinal tract may be used in the detection of diffuse axonal injury. The association between decreased motoricity index and decreased FA suggests that DTI may be useful in evaluating patients with traumatic brain injury.

Adult↗