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Kim SH, Kang JG, Kim CS, Ihm SH, Choi MG, Yoo HJ, Lee SJ. Gemigliptin, a novel dipeptidyl peptidase-IV inhibitor, exerts a synergistic cytotoxicity with the histone deacetylase inhibitor PXD101 in thyroid carcinoma cells. J Endocrinol Invest 2018; 41:677-689. [PMID: 29147952 DOI: 10.1007/s40618-017-0792-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/16/2017] [Accepted: 11/02/2017] [Indexed: 02/08/2023]
Abstract
PURPOSE The influence of the dipeptidyl peptidase-IV inhibitor gemigliptin alone or in combination with the histone deacetylase inhibitor PXD101 on survival of thyroid carcinoma cells was investigated. METHODS SW1736, TPC-1, 8505C and BCPAP human thyroid carcinoma cells were used. To assess cell survival, cell viability, the percentage of viable cells and dead cells, cytotoxic activity, ATP levels and FACS analysis were measured. To validate the impact of gemigliptin combined with PXD101, the interactions were estimated by obtaining combination index in cells treated with two agents. RESULTS In cells treated with gemigliptin or PXD101, cell viability, the percentage of viable cells and ATP levels were reduced, and the percentage of dead cells and cytotoxic activity were elevated. In cells treated with both gemigliptin and PXD101, compared with PXD101 alone, cell death was augmented, and all of the combination index values were lower than 1.0, suggesting the synergism between gemigliptin and PXD101. The percentage of apoptotic cells, and the protein levels of Bcl2 and cleaved poly (ADP-ribose) polymerase were elevated, and the protein levels of xIAP and survivin were reduced. The protein levels of phospho-Akt and phospho-AMPK were elevated, and cell migration was reduced. CONCLUSIONS Our results demonstrate that gemigliptin induces cytotoxicity in thyroid carcinoma cells. Moreover, gemigliptin has a synergistic activity with PXD101 in the induction of cell death through involvement of Bcl2 family proteins, xIAP and survivin as well as mediation of Akt and AMPK in thyroid carcinoma cells.
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Jackson EM, Nolde JA, Kim M, Kim CS, Cleveland ER, Affouda CA, Canedy CL, Vurgaftman I, Meyer JR, Aifer EH, Lorentzen J. Two-dimensional plasmonic grating for increased quantum efficiency in midwave infrared nBn detectors with thin absorbers. OPTICS EXPRESS 2018; 26:13850-13864. [PMID: 29877431 DOI: 10.1364/oe.26.013850] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2018] [Accepted: 04/16/2018] [Indexed: 06/08/2023]
Abstract
We demonstrate a strategy for increasing the operating temperatures of nBn midwave infrared (MWIR) focal plane arrays, based on the use of two-dimensional plasmonic gratings to enhance the quantum efficiency (QE) of structures with very thin absorbers. Reducing the absorber volume correspondingly reduces the dark current in a diffusion-limited photodiode, while light trapping mediated by the plasmonic grating increases the net absorbance to maintain high QE. The plasmonically enhanced nBn MWIR sensors with absorber thicknesses of only 0.5 μm exhibit peak internal QEs as high as 57%, which enables a 5-fold reduction in dark current. Numerical simulations indicate the potential for further improvement.
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Kim CS, Brager DH, Johnston D. Perisomatic changes in h-channels regulate depressive behaviors following chronic unpredictable stress. Mol Psychiatry 2018; 23:892-903. [PMID: 28416809 PMCID: PMC5647208 DOI: 10.1038/mp.2017.28] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/28/2016] [Revised: 01/10/2017] [Accepted: 01/17/2017] [Indexed: 12/23/2022]
Abstract
Chronic stress can be a precipitating factor in the onset of depression. Lentiviral-mediated knockdown of HCN1 protein expression and reduction of functional Ih produce antidepressant behavior. However, whether h-channels are altered in an animal model of depression is not known. We found that perisomatic HCN1 protein expression and Ih-sensitive physiological measurements were significantly increased in dorsal but not in ventral CA1 region/neurons following chronic unpredictable stress (CUS), a widely accepted model for major depressive disorder. Cell-attached patch clamp recordings confirmed that perisomatic Ih was increased in dorsal CA1 neurons following CUS. Furthermore, when dorsal CA1 Ih was reduced by shRNA-HCN1, the CUS-induced behavioral deficits were prevented. Finally, rats infused in the dorsal CA1 region with thapsigargin, an irreversible inhibitor of the SERCA pump, exhibited anxiogenic-like behaviors and increased Ih, similar to that observed following CUS. Our results suggest that CUS, but not acute stress, leads to an increase in perisomatic Ih in dorsal CA1 neurons and that HCN channels represent a potential target for the treatment of major depressive disorder.
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Lee SH, Oh JS, Lee KB, Lee JM, Hwang SH, Lee MK, Kwon EH, Kim CS, Choi IH, Yeo IY, Yoon JY, Im JM. Evaluation of abundance of artificial radionuclides in food products in South Korea and sources. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2018; 184-185:46-52. [PMID: 29334620 DOI: 10.1016/j.jenvrad.2018.01.008] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/06/2017] [Revised: 01/04/2018] [Accepted: 01/08/2018] [Indexed: 06/07/2023]
Abstract
Food samples are collected nationwide from January 2016 to February 2017 and their contents of artificial radionuclides are measured to address the growing concerns regarding the radioactive contamination of food products in Korea. Specifically, 900 food samples are collected for this study and their contents of representative artificial radionuclides 134Cs, 137Cs, 239,240Pu, and 90Sr are analyzed. The analysis shows that the activity concentrations of 137Cs in fish range from minimum detectable activity (MDA) to 340 mBq/kg of fresh weight. The concentration factor (CF) determined for 137Cs as a measure of its bioavailability is calculated to be ca. 74 and found to be very similar to that (100) recommended by the International Atomic Energy Agency. With an MDA of <0.221 mBq/kg, the results reveal that 239,240Pu values in fish are below the MDA. The activity concentrations of 137Cs and 90Sr are lower than the MDA in both shellfish and seaweed, while the activity concentrations of 239,240Pu in shellfish range from 0.26 to 2.18 mBq/kg, and for seaweed samples range from 2.07 to 3.38 mBq/kg. The atom ratios of 240Pu/239Pu in shellfish caught at the Korean coast vary from 0.209 to 0.237, with a mean of 0.227. The higher 240Pu/239Pu atom ratio determined in shellfish is thought to be caused by the plutonium transported from the Pacific Proving Grounds rather than other sources such as the Fukushima nuclear power plant accident. The activity concentrations of 137Cs in mushrooms are found to vary from 1.0 to 21.4 Bq/kg, with the highest concentrations observed in the Oak (shiitake) and Sarcodon asparatus. 134Cs is detected in three mushroom specimens collected from Jeju Island and about 3-3.6% of 137Cs present in the wild mushrooms native to the Jeju Island are introduced as a result of the Fukushima nuclear plant accident. The annual effective doses of 137Cs received through consumption of mushrooms and fish are 2.0 × 10-4 mSv yr-1 and 3.9 × 10-5 mSv yr-1, and those values are negligible compared to the annual effective doses limit of 1 mSv yr-1.
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Park JY, Kwak DH, Ma KB, Han SB, Chai GS, Kim SK, Peck DH, Kim CS, Kucernak A, Park KW. Enhanced oxygen reduction reaction of Pt deposited Fe/N-doped bimodal porous carbon nanostructure catalysts. J Catal 2018. [DOI: 10.1016/j.jcat.2017.12.033] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Yang H, Park J, Kim CS, Xu YH, Zhu HL, Qi YX, Yin L, Li H, Lun N, Bai YJ. Uniform Surface Modification of Li 2ZnTi 3O 8 by Liquated Na 2MoO 4 To Boost Electrochemical Performance. ACS APPLIED MATERIALS & INTERFACES 2017; 9:43603-43613. [PMID: 29172428 DOI: 10.1021/acsami.7b12208] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Poor ionic and electronic conductivities are the key issues to affect the electrochemical performance of Li2ZnTi3O8 (LZTO). In view of the water solubility, low melting point, good electrical conductivity, and wettability to LZTO, Na2MoO4 (NMO) was first selected to modify LZTO via simply mixing LZTO in NMO water solution followed by calcining the dried mixture at 750 °C for 5 h. The electrochemical performance of LZTO could be enhanced by adjusting the content of NMO, and the modified LZTO with 2 wt % NMO exhibited the most excellent rate capabilities (achieving lithiation capacities of 225.1, 207.2, 187.1, and 161.3 mAh g-1 at 200, 400, 800, and 1600 mA g-1, respectively) as well as outstanding long-term cycling stability (delivering a lithiation capacity of 229.0 mAh g-1 for 400 cycles at 500 mA g-1). Structure and composition characterizations together with electrochemical impedance spectra analysis demonstrate that the molten NMO at the sintering temperature of 750 °C is beneficial to diffuse into the LZTO lattices near the surface of LZTO particles to yield uniform modification layer, simultaneously ameliorating the electronic and ionic conductivities of LZTO, and thus is responsible for the enhanced electrochemical performance of LZTO. First-principles calculations further verify the substitution of Mo6+ for Zn2+ to realize doping in LZTO. The work provides a new route for designing uniform surface modification at low temperature, and the modification by NMO could be extended to other electrode materials to enhance the electrochemical performance.
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Kim DW, Kim CS, Kim HJ, Lee YM, Kim HJ, Kwon KB. The Effect of Germanium Treatment on Rain Shelter House Cultivation of Korean Ginseng (Panax ginseng C. A. Meyer). Am J Transl Res 2017. [DOI: 10.1055/s-0037-1608510] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Kang Nu R, Kim CS, Lee Ik S, Kim Young S, Kim Jin S. Puerariae radix extract suppresses H2O2-induced ARPE-19 cell death and permeability via phosphorylation of p38MAPK and JNK. Am J Transl Res 2017. [DOI: 10.1055/s-0037-1608418] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Hou Y, Qiu M, Zhang T, Zhuang X, Kim CS, Yuan C, Feng X. Ternary Porous Cobalt Phosphoselenide Nanosheets: An Efficient Electrocatalyst for Electrocatalytic and Photoelectrochemical Water Splitting. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2017; 29:1701589. [PMID: 28714078 DOI: 10.1002/adma.201701589] [Citation(s) in RCA: 58] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/21/2017] [Revised: 06/08/2017] [Indexed: 05/26/2023]
Abstract
Exploring efficient and earth-abundant electrocatalysts is of great importance for electrocatalytic and photoelectrochemical hydrogen production. This study demonstrates a novel ternary electrocatalyst of porous cobalt phosphoselenide nanosheets prepared by a combined hydrogenation and phosphation strategy. Benefiting from the enhanced electric conductivity and large surface area, the ternary nanosheets supported on electrochemically exfoliated graphene electrodes exhibit excellent catalytic activity and durability toward hydrogen evolution in alkali, achieving current densities of 10 and 20 mA cm-2 at overpotentials of 150 and 180 mV, respectively, outperforming those reported for transition metal dichalcogenides and first-row transition metal pyrites catalysts. Theoretical calculations reveal that the synergistic effects of Se vacancies and subsequent P displacements of Se atoms around the vacancies in the resulting cobalt phosphoselenide favorably change the electronic structure of cobalt selenide, assuring a rapid charge transfer and optimal energy barrier of hydrogen desorption, and thus promoting the proton kinetics. The overall-water-splitting with 10 mA cm-2 at a low voltage of 1.64 V is achieved using the ternary electrode as both the anode and cathode, and the performance surpasses that of the Ir/C-Pt/C couple for sufficiently high overpotentials. Moreover, the integration of ternary nanosheets with macroporous silicon enables highly efficient solar-driven photoelectrochemical hydrogen production.
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Park MB, Kim CB, Ranabhat C, Kim CS, Chang SJ, Ahn DW, Joo YK. Influence of community satisfaction with individual happiness: comparative study in semi-urban and rural areas of Tikapur, Nepal. Glob Health Promot 2017; 25:22-32. [PMID: 28719754 DOI: 10.1177/1757975916672169] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Happiness is a subjective indicator of overall living conditions and quality of life. Recently, community- and national-level investigations connecting happiness and community satisfaction were conducted. This study investigated the effects of community satisfaction on happiness in Nepal. A factor analysis was employed to examine 24 items that are used to measure community satisfaction, and a multiple regression analysis was conducted to investigate the effects of these factors on happiness. In semi-urban areas, sanitation showed a positive relationship with happiness. In rural areas, edu-medical services were negatively related to happiness, while agriculture was positively related. Gender and perceived health were closely associated with happiness in rural areas. Both happiness and satisfaction are subjective concepts, and are perceived differently depending on the socio-physical environment and personal needs. Sanitation, agriculture (food) and edu-medical services were critical factors that affected happiness; however, the results of this study cannot be generalized to high-income countries.
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Nam HS, Kim CS, Lee JJ, Song JW, Kim JW, Yoo H. Automated detection of vessel lumen and stent struts in intravascular optical coherence tomography to evaluate stent apposition and neointimal coverage. Med Phys 2016; 43:1662. [PMID: 27036565 DOI: 10.1118/1.4943374] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
PURPOSE Intravascular optical coherence tomography (IV-OCT) is a high-resolution imaging method used to visualize the microstructure of arterial walls in vivo. IV-OCT enables the clinician to clearly observe and accurately measure stent apposition and neointimal coverage of coronary stents, which are associated with side effects such as in-stent thrombosis. In this study, the authors present an algorithm for quantifying stent apposition and neointimal coverage by automatically detecting lumen contours and stent struts in IV-OCT images. METHODS The algorithm utilizes OCT intensity images and their first and second gradient images along the axial direction to detect lumen contours and stent strut candidates. These stent strut candidates are classified into true and false stent struts based on their features, using an artificial neural network with one hidden layer and ten nodes. After segmentation, either the protrusion distance (PD) or neointimal thickness (NT) for each strut is measured automatically. In randomly selected image sets covering a large variety of clinical scenarios, the results of the algorithm were compared to those of manual segmentation by IV-OCT readers. RESULTS Stent strut detection showed a 96.5% positive predictive value and a 92.9% true positive rate. In addition, case-by-case validation also showed comparable accuracy for most cases. High correlation coefficients (R > 0.99) were observed for PD and NT between the algorithmic and the manual results, showing little bias (0.20 and 0.46 μm, respectively) and a narrow range of limits of agreement (36 and 54 μm, respectively). In addition, the algorithm worked well in various clinical scenarios and even in cases with a low level of stent malapposition and neointimal coverage. CONCLUSIONS The presented automatic algorithm enables robust and fast detection of lumen contours and stent struts and provides quantitative measurements of PD and NT. In addition, the algorithm was validated using various clinical cases to demonstrate its reliability. Therefore, this technique can be effectively utilized for clinical trials on stent-related side effects, including in-stent thrombosis and in-stent restenosis.
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Freidoony L, Ranabhat CL, Kim CB, Kim CS, Ahn DW, Doh YA. Predisposing, enabling, and need factors associated with utilization of institutional delivery services: A community-based cross-sectional study in far-western Nepal. Women Health 2016; 58:51-71. [PMID: 27929757 DOI: 10.1080/03630242.2016.1267689] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
Use of institutional delivery services can be effective in reducing maternal and infant mortality. In Nepal, however, the majority of women deliver at home. Using Andersen's behavioral model of use of health care services, this cross-sectional study aimed to identify factors associated with use of institutional delivery services in four villages and one municipality in Kailali district, Nepal. Mothers (N = 500) who had given birth in the 5 years preceding the survey (conducted between January and February 2015) were randomly selected by cluster sampling and interviewed using a semi-structured questionnaire. Bivariate analyses and multivariate hierarchical logistic regression analyses were performed. Among the women surveyed, 65.6% had used institutional delivery services for their last delivery, a higher proportion than the national average. Primiparity, having a secondary or higher education level, living in the Durgauli village, having husbands with occupations other than agriculture or professional/technical jobs, and having attended four or more antenatal care (ANC) visits had significantly increased use of institutional deliveries. Also, belonging to the richest 20% of the community and having experienced pregnancy complications were marginally significantly associated. These findings demonstrate the need for improving mother's education, encouraging them to attend ANC visits and addressing disparities between different regions.
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Park H, Jung K, Nezafati M, Kim CS, Kang B. Sodium Ion Diffusion in Nasicon (Na 3Zr 2Si 2PO 12) Solid Electrolytes: Effects of Excess Sodium. ACS APPLIED MATERIALS & INTERFACES 2016; 8:27814-27824. [PMID: 27700032 DOI: 10.1021/acsami.6b09992] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
The Na superionic conductor (aka Nasicon, Na1+xZr2SixP3-xO12, where 0 ≤ x ≤ 3) is one of the promising solid electrolyte materials used in advanced molten Na-based secondary batteries that typically operate at high temperature (over ∼270 °C). Nasicon provides a 3D diffusion network allowing the transport of the active Na-ion species (i.e., ionic conductor) while blocking the conduction of electrons (i.e., electronic insulator) between the anode and cathode compartments of cells. In this work, the standard Nasicon (Na3Zr2Si2PO12, bare sample) and 10 at% Na-excess Nasicon (Na3.3Zr2Si2PO12, Na-excess sample) solid electrolytes were synthesized using a solid-state sintering technique to elucidate the Na diffusion mechanism (i.e., grain diffusion or grain boundary diffusion) and the impacts of adding excess Na at relatively low and high temperatures. The structural, thermal, and ionic transport characterizations were conducted using various experimental tools including X-ray diffraction (XRD), differential scanning calorimetry (DSC), scanning electron microscopy (SEM), and electrochemical impedance spectroscopy (EIS). In addition, an ab initio atomistic modeling study was carried out to computationally examine the detailed microstructures of Nasicon materials, as well as to support the experimental observations. Through this combination work comprising experimental and computational investigations, we show that the predominant mechanisms of Na-ion transport in the Nasicon structure are the grain boundary and the grain diffusion at low and high temperatures, respectively. Also, it was found that adding 10 at% excess Na could give rise to a substantial increase in the total conductivity (e.g., ∼1.2 × 10-1 S/cm at 300 °C) of Nasicon electrolytes resulting from the enlargement of the bottleneck areas in the Na diffusion channels of polycrystalline grains.
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Kim G, Lee YH, Jeon JY, Bang H, Lee BW, Kang ES, Lee IK, Cha BS, Kim CS. Increase in resting heart rate over 2 years predicts incidence of diabetes: A 10-year prospective study. DIABETES & METABOLISM 2016; 43:25-32. [PMID: 27745827 DOI: 10.1016/j.diabet.2016.09.002] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/28/2016] [Revised: 08/26/2016] [Accepted: 09/06/2016] [Indexed: 10/20/2022]
Abstract
OBJECTIVE The association between resting heart rate (RHR) and the development of diabetes has yet to be fully elucidated, and the relationship between changes in RHR and incidence of diabetes also remains unclear. Our study aimed to investigate the association between changes in RHR over 2 years and the risk of diabetes. METHODS A total of 7416 adults without diabetes were included. All had participated in the Korean Genome and Epidemiology Study, a community-based, 10-year prospective study in which RHR was measured at baseline and 2 years later. Incident diabetes was defined as fasting blood glucose ≥126mg/dL, 2-h post-load glucose ≥200mg/dL during a 75-g oral glucose tolerance test or current use of diabetes medication. The relative risk of diabetes associated with the 2-year change in RHR was calculated using Cox models. RESULTS During the 10-year follow-up, 1444 (19.5%) developed diabetes. Compared with RHR increases <5 beats per minute (bpm) over 2 years, increases >10bpm were significantly associated with development of diabetes (adjusted hazard ratio: 1.31, 95% confidence interval: 1.06-1.60), even after adjusting for glycometabolic parameters and baseline RHR. This significant association was attenuated in people who exercised regularly (P=0.650), but remained significant in those not doing any regular exercise (P=0.010). CONCLUSION An increase in RHR over a 2-year follow-up period is significantly associated with a risk of diabetes, independently of baseline RHR and glycometabolic parameters. Further investigations into ways to control RHR as a potential preventative measure against the development of diabetes are now needed.
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Kim CS, Lee SK, Keum YS. Comparative studies of immobilized lipase- and acid-catalyzed fatty acid methyl ester synthesis for seed lipid analysis. Food Sci Biotechnol 2016; 25:771-776. [PMID: 30263335 DOI: 10.1007/s10068-016-0131-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2015] [Revised: 12/30/2015] [Accepted: 03/27/2016] [Indexed: 11/28/2022] Open
Abstract
Fatty acids are one of the most important nutrients in food. Acid- or base-catalyzed transesterification methods are commonly used for the analysis of fatty acids. However, several drawbacks were reported for these methods, including the isomerization and degradation of fatty acids. Lipase-catalyzed reactions are usually undertaken at mild conditions, preventing such problems. In this study, commercial resin-bound lipase from Candida antartica was tested for possible application in fatty acid methyl ester analysis. Experimental parameters, including temperature, reaction time, and re-cycling were evaluated. The optimized condition was (5-10 mg lipid, 0.5 mL of MeOH, and 50 mg Novozyme 435 in 2 mL toluene, 80°C for 1 h). In optimized condition, the lipase-catalyzed methods yielded similar results with the chemical method. In overall, lipase-catalyzed transesterification can be a useful alternative to acid-catalyzed methods for fatty acid analysis.
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Kim CS, Sapienza PP, Ross IA, Johnson W, Luu HMD, Hutter JC. Distribution of bisphenol A in the neuroendocrine organs of female rats. Toxicol Ind Health 2016; 20:41-50. [PMID: 15807407 DOI: 10.1191/0748233704th186oa] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
The distribution of 14C-bisphenol A (BPA) in plasma and neuroendocrine organs was determined in Fischer 344 female rats following three oral doses (0.1, 10 or 100 mg/kg). Plasma and tissue maximum concentrations (Cmax) were reached within 15-30 min of dosing. Plasma areas-under-the-curve (AUC) ranged from 0.06 to 53.9 mg-h/mL. The AUCs of the pituitary gland and uterus/gonads were 16-21% higher than that of plasma. The AUCs of hypothalamus and the rest of the brain were 43.7% and 77% of the plasma AUCs, respectively. In the brain tissue, the exposure increased linearly with the oral dose, as the dose was increased from 0.1 to 10 and 100 mg/kg; the exposure in the brain relative to the plasma increased by factors of 1, 1.19 and 1.24. This indicates that the brain barrier systems do not limit the access of the lipophilic BPA to the brain. The increases of the uterus/gonads relative to the plasma were 1, 1.07 and 1.04. Tissue partitioning was also examined in vitro by the uptake of 14C-BPA. The BPA tissue/blood partition coefficients were as follows: heart, 7.5; liver, 6.1; kidney, 6.4; fat, 3.6; muscle, 2.6; breast, 3.6; ovaries, 9.1; uterus, 5.9; stomach, 5.1; and small intestine, 6.7. The tissue/cerebrospinal fluid partition coefficients were as follows: pituitary gland, 12.8; brain stem, 6.1; cerebellum, 6.4; hippocampus, 7.1; hypothalamus, 6.1; frontal cortex, 4.9; and caudate nucleus, 6.8.
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Xu Y, Kim CS, Saylor DM, Koo D. Polymer degradation and drug delivery in PLGA-based drug-polymer applications: A review of experiments and theories. J Biomed Mater Res B Appl Biomater 2016; 105:1692-1716. [PMID: 27098357 DOI: 10.1002/jbm.b.33648] [Citation(s) in RCA: 223] [Impact Index Per Article: 27.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2015] [Revised: 01/25/2016] [Accepted: 02/12/2016] [Indexed: 01/03/2023]
Abstract
Poly (lactic-co-glycolic acid) (PLGA) copolymers have been broadly used in controlled drug release applications. Because these polymers are biodegradable, they provide an attractive option for drug delivery vehicles. There are a variety of material, processing, and physiological factors that impact the degradation rates of PLGA polymers and concurrent drug release kinetics. This work is intended to provide a comprehensive and collective review of the physicochemical and physiological factors that dictate the degradation behavior of PLGA polymers and drug release from contemporary PLGA-based drug-polymer products. In conjunction with the existing experimental results, analytical and numerical theories developed to predict drug release from PLGA-based polymers are summarized and correlated with the experimental observations. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 1692-1716, 2017.
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Xu Y, Koo D, Gerstein EA, Kim CS. Multi-scale modeling of polymer–drug interactions and their impact on the structural evolutions in PLGA-tetracycline films. POLYMER 2016. [DOI: 10.1016/j.polymer.2015.12.052] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
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Trofimov IE, Canedy CL, Kim CS, Kim M, Bewley WW, Merritt CL, Vurgaftman I, Meyer JR, Le LT. Interband cascade lasers with long lifetimes. APPLIED OPTICS 2015; 54:9441-9445. [PMID: 26560770 DOI: 10.1364/ao.54.009441] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Narrow-ridge interband cascade lasers were subjected to accelerated aging. The aging curves were statistically evaluated by a log-normal distribution of the failure time, and by the mixed effects of the degradation parameters. Based on 10,000 h of output power trend data for lasers operating at 90°C and the maximum cw power, an unexpectedly long lifetime is predicted. The projected lifetimes range from about 500,000 h (57 years) for the linear degradation model to 183,000 h (21 years) for the exponential one.
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Yang SM, Kim SRN, Youn WK, Kim CS, Kim DS, Yi KW, Hwang NM. Generation of Charged Nanoparticles During Thermal Evaporation of Silver at Atmospheric Pressure. JOURNAL OF NANOSCIENCE AND NANOTECHNOLOGY 2015; 15:8418-8423. [PMID: 26726527 DOI: 10.1166/jnn.2015.11458] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
The generation of charged silver nanoparticles in the gas phase during thermal evaporation of silver at atmospheric pressure was confirmed by the nano-differential mobility analyzer (DMA). Effects of the evaporation temperature, the nitrogen gas flow rate and the amount of silver to be evaporated on the size distribution of charged nanoparticles (CNPs) were examined. Both positively and negatively-charged nanoparticles were generated under all processing conditions adopted in this study. The deposition behavior of CNPs was affected by the gas flow, which is affected by the temperature gradient in the reactor and by the applied electric bias. The electric bias, which not only enhanced the film growth rate but also produced a much denser film surface, turned out to be an important process parameter under the condition where an appreciable amount of CNPs is generated.
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Merritt CD, Bewley WW, Kim CS, Canedy CL, Vurgaftman I, Meyer JR, Kim M. Gain and loss as a function of current density and temperature in interband cascade lasers. APPLIED OPTICS 2015; 54:F1-F7. [PMID: 26560596 DOI: 10.1364/ao.54.0000f1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
We characterize the internal efficiency, internal loss, and optical gain versus current density in 7-stage interband cascade lasers operating at λ=3.1 and 3.45 μm using a cavity-length study of the external differential quantum efficiency (EDQE) and threshold current density at temperatures between 300 and 345 K. We find that the pronounced efficiency droop of the EDQE at high current densities is primarily due to an increase in the internal loss rather than a reduction in the internal efficiency. On the other hand, if the current density J is fixed, the temperature variation of the EDQE at that J is due primarily to a decrease of the internal efficiency. The gain versus current density is fit well by a logarithmic relationship, although the magnitude of the experimental gain is >20% below the theoretical estimate.
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Northern JH, O'Hagan S, Fletcher B, Gras B, Ewart P, Kim CS, Kim M, Merritt CD, Bewley WW, Canedy CL, Abell J, Vurgaftman I, Meyer JR. Mid-infrared multi-mode absorption spectroscopy using interband cascade lasers for multi-species sensing. OPTICS LETTERS 2015; 40:4186-9. [PMID: 26368743 DOI: 10.1364/ol.40.004186] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
An interband cascade laser (ICL) operating at 3.7 μm has been used to perform multimode absorption spectroscopy, MUMAS, at scan rates up to 10 kHz. Line widths of individual modes in the range 10-80 MHz were derived from isolated lines in the MUMAS signatures of HCl. MUMAS data for methane covering a spectral range of 30 nm yielded a detection level of 30 μbar·m for 1 s measurement time at 100 Hz. Simultaneous detection of methane, acetylene, and formaldehyde in a gas mixture containing all three species is reported.
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Ranabhat CL, Kim CB, Kim CS, Jha N, Deepak KC, Connel FA. Consequence of indoor air pollution in rural area of Nepal: a simplified measurement approach. Front Public Health 2015; 3:5. [PMID: 25674557 PMCID: PMC4306325 DOI: 10.3389/fpubh.2015.00005] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2014] [Accepted: 01/06/2015] [Indexed: 12/04/2022] Open
Abstract
People of developing countries especially from rural area are commonly exposed to high levels of household pollution for 3–7 h daily using biomass in their kitchen. Such biomass produces harmful smoke and makes indoor air pollution (IAP). Community-based cross-sectional study was performed to identify effects of IAP by simplified measurement approach in Sunsari District of Nepal. Representative samples of 157 housewives from household, involving more than 5 years in kitchen were included by cluster sampling. Data were analyzed by SPSS and logistic regression was applied for the statistical test. Most (87.3%) housewives used biomass as a cooking fuel. Tearing of eyes, difficulty in breathing, and productive cough were the main reported health problems and traditional mud stoves and use of unrefined biomass were statistically significant (p < 0.05) and more risk (AOR > 2) with health problems related to IAP. The treatment cost and episodes of acute respiratory infection was >2 folders higher in severe IAP than mild IAP. Simplified measurement approach could be helpful to measure IAP in rural area. Some effective intervention is suggested to reduce the severe level of IAP considering women and children.
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Cho YI, Kim CS, Kim JH. Evaluation of syringe shield effectiveness in handling radiopharmaceuticals. NUCLEAR TECHNOLOGY AND RADIATION PROTECTION 2015. [DOI: 10.2298/ntrp1502158c] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
The purpose of this study was to evaluate the effectiveness of the radiation
shield of radionuclide syringes and the personal dose equivalent by
performing a simulation of radionuclides used in nuclear medicine diagnosis.
In order to evaluate the dose depending on the distance between the radiation
source and the ICRU sphere against the thickness of the shielding device, the
distance at which a nuclear medicine worker may inadvertently come into
contact with radiation from the radiation source was set at 0 cm to 30 cm
according to the thickness of the shield, thus fixing the ICRU sphere. For a
dose evaluation, Hp(10), Hp(3), and Hp(0.07) measurable in specific depth of
the ICRU were evaluated. It was found that a dose measured on skin surface of
nuclear medicine workers was relatively higher, that the dose varied in
relation to the thickness of the radiation shield, and that the shielding
effect decreased for some radiation sources such as 67Ga and 111In. It proved
necessary to increase thickness of shielding device to the radiation sources
such as 67Ga and 111In. It is also considered that a study of proper
shielding thickness will be needed in future.
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