Mitochondrial Ca²⁺ Uptake Relieves Palmitate-Induced Cytosolic Ca²⁺ Overload in MIN6 Cells

Ly, Luong Dai,Ly, Dat Da,Nguyen, Nhung Thi,Kim, Ji-Hee,Yoo, Heesuk,Chung, Jongkyeong,Lee, Myung-Shik,Cha, Seung-Kuy,Park, Kyu-Sang Korean Society for Molecular and Cellular Biology 2020 Molecules and cells Vol.43 No.1

Saturated fatty acids contribute to β-cell dysfunction in the onset of type 2 diabetes mellitus. Cellular responses to lipotoxicity include oxidative stress, endoplasmic reticulum (ER) stress, and blockage of autophagy. Palmitate induces ER Ca²⁺ depletion followed by notable store-operated Ca²⁺ entry. Subsequent elevation of cytosolic Ca²⁺ can activate undesirable signaling pathways culminating in cell death. Mitochondrial Ca²⁺ uniporter (MCU) is the major route for Ca²⁺ uptake into the matrix and couples metabolism with insulin secretion. However, it has been unclear whether mitochondrial Ca²⁺ uptake plays a protective role or contributes to lipotoxicity. Here, we observed palmitate upregulated MCU protein expression in a mouse clonal β-cell, MIN6, under normal glucose, but not high glucose medium. Palmitate elevated baseline cytosolic Ca²⁺ concentration ([Ca²⁺]_i) and reduced depolarization-triggered Ca²⁺ influx likely due to the inactivation of voltage-gated Ca²⁺ channels (VGCCs). Targeted reduction of MCU expression using RNA interference abolished mitochondrial superoxide production but exacerbated palmitate-induced [Ca²⁺]_i overload. Consequently, MCU knockdown aggravated blockage of autophagic degradation. In contrast, co-treatment with verapamil, a VGCC inhibitor, prevented palmitate-induced basal [Ca²⁺]_i elevation and defective [Ca²⁺]_i transients. Extracellular Ca²⁺ chelation as well as VGCC inhibitors effectively rescued autophagy defects and cytotoxicity. These observations suggest enhanced mitochondrial Ca²⁺ uptake via MCU upregulation is a mechanism by which pancreatic β-cells are able to alleviate cytosolic Ca²⁺ overload and its detrimental consequences.

Geological and mineralization characteristics of the Kestanelik epithermal Au-Ag deposit in the Tethyan Metallogenic Belt, NW Turkey

Nilay Gülyüz,Erhan Gülyüz,Zoe K. Shipton,İlkay Kuşcu,Richard A. Lord 한국지질과학협의회 2020 Geosciences Journal Vol.24 No.4

Kestanelik epithermal gold deposit is situated in the Biga Peninsula, which hosts numerous metallic deposits belonging to the Tethyan Metallogenic Belt. In the Biga peninsula the Tethyan Metallogenic Belt is represented by a Neo-Tethyan suture zone. Discovered deposits along the belt are commonly associated with Cenozoic magmatism ranging between 52 and 18 Ma in age, formed due syn- to post-collisional tectonics. In this study, we focus on the deposit-scale geological and mineralization characteristics of Kestanelik in order to determine the formation and evolution of the deposit within the tectono-magmatic history of the Biga Peninsula. We (1) mapped the geology of the deposit area (2) conducted paleostress analyses, (3) observed and examined the macroscopic and petrographical textural, mineralogical and alteration characteristics of the mineralization and (4) interpreted geophysical resistivity survey and geochemical assay data. The stratigraphic age of the Kestanelik deposit, bracketed by cross cutting relations and supported by the geophysical data, is middle Lutetian–early Priabonian which also implies that the deposit has a genetic link with the Cenozoic post-collisional calc-alkaline magmatism. A NE-SW oriented compressional regime determined from the paleostress analyses is consistent with the kinematics of the vein system and is attributed to the collision and further convergence after the closure of the northern branch of the Neo-Tethys Ocean. The fracture system provided structural pathways for the transport of the hydrothermal fluids. The common presence of pseudo-bladed quartz and hydrothermal breccias, and the low total sulphide and base metal contents in the mineralized veins indicate that the Kestanelik is a low sulphidation epithermal-type gold deposit. Boiling, mixing (hypogene oxidation) and supergene enrichment are the likely gold deposition and enrichment processes respectively.

Nondestructive Characterization of Graphene Defects

Ly, Thuc Hue,Duong, Dinh Loc,Ta, Quang Huy,Yao, Fei,Vu, Quoc An,Jeong, Hye Yun,Chae, Sang Hoon,Lee, Young Hee WILEY‐VCH Verlag 2013 Advanced functional materials Vol.23 No.41

<P><B>Abstract</B></P><P>An effective method is reported for oxidizing graphene/copper film in which air oxidation of the underlying copper film occurs through the grain boundary lines of graphene without oxidizing graphene. This oxidation is realized by partially immersing the graphene/copper film in sodium chloride solution. Electrons generated during etching of the graphene/copper film in electrolyte diffuse into the film in contact with air, which eventually enhances air oxidation of copper through the graphene layer. While the graphene layer acts as a protective layer against oxidation of the copper film, oxidation of the underlying Cu film near graphene grain boundary lines is observed by optical microscopy. This observation could be attributed to the selective diffusion of oxygen radicals through isolated defects and graphene grain boundaries. The process involves no appreciable oxidation of the graphene layer including the graphene grain boundary, as confirmed by use of detailed Raman and X‐ray photoelectron spectroscopy.</P>

Direct Assay of Riboflavin in Cow's Milk Using Graphite Pencil Electrode

Ly, Suw Young 서울産業大學校 2005 논문집 Vol.54 No.4

Direct detecting method of riboflavin (vitamin B2.VB2) in cow's milk was developed using stripping voltammetry analysis with graphite pencil electrode (GPE). The results show a sensitive oxidation peak current of VB₂ on the GPE. Commonly used working electrodes were compared and better results were obtained with GPE than with the common electrodes. Analytical working concentration ranged within 10-100.0 and 50.0-350 mgL^(-1)VB₂, with pre-concentration time of 160 sec. The relative standard deviation of 50, 150, and 200 mgL^(-1) observed were 0.069, 0.084, and 0.081% (n = 15), respectively, using optimum conditions. The detection limit (S/N) was pegged at 0.20 ugL^(-1). Results show that the method developed can be used to assay untreated natural milk solution, as well as other materials requiring Vitamin B₂ analysis.

Fast pyrolysis of Saccharina japonica alga in a fixed-bed reactor for bio-oil production

Ly, H.V.,Kim, S.S.,Choi, J.H.,Woo, H.C.,Kim, J. Pergamon ; Elsevier Science Ltd 2016 Energy conversion and management Vol.122 No.-

Macro-algae are recognized as a potential feedstock for renewable energy and fuel production. Saccharina japonica is a kind of macro-algae that has been extensively cultivated in Korea. Through pyrolysis, S. japonica can be converted into bio-oil, gas, and char. In this study, we investigated the fast pyrolysis of S. japonica in a fixed-bed reactor at different temperatures from 350 to 550<SUP>o</SUP>C with sweeping-gas flow rates of 100, 300, and 500ml/min. As the pyrolysis temperature was increased from 350<SUP>o</SUP>C to 500<SUP>o</SUP>C, the bio-oil yields decreased while the gas yields increased. The highest liquid yield (40.91wt%) was obtained at a pyrolysis temperature of 350<SUP>o</SUP>C with a sweeping-gas velocity of 300ml/min. The major compositions in the bio-oil were di-anhydromannitol (34.45%), iso-sorbide (19.84%), and 2-methyl furyl ketone (8.43%). The gas products (including CO, CO<SUB>2</SUB>, H<SUB>2</SUB>, and hydrocarbon gases from C<SUB>1</SUB> to C<SUB>4</SUB>), were analyzed by gas chromatography with an FID and a TCD. The bio-chars contained a high carbonaceous content can be used as a pollution-free solid fuel or for the production of activated carbon and other chemicals.

Atomistic study of the alloying behavior of crystalline SnSe1-xSx

Ly, T.,Duvjir, G.,Min, T.,Byun, J.,Kim, T.,Saad, M.,Hai, N.,Cho, S.,Lee, J.,Kim, J. Royal Society of Chemistry 2017 Physical chemistry chemical physics Vol.19 No.32

Adaptive Cuckoo Search Algorithm for Economic Emission Load Dispatch Problem

Ly Huu Pham,Thang Trung Nguyen,Bach Hoang Dinh 보안공학연구지원센터 2016 International Journal of Hybrid Information Techno Vol.9 No.4

This paper proposes an Adaptive Cuckoo Search Algorithm (ACSA) for solving economic emission dispatch (EELD) problem with quadratic fuel function. The ACSA is developed by performing two adaptive updated step size parameters on conventional CSA in aim to enhance the convergence speed and quality solution of the conventional CSA. In addition to minimizing electricity generation fuel cost, emission released into the air from thermal plants is also another main objective needs to be minimized. In order to test the performance of the proposed ACSA two systems including a three unit system with one load case and a six unit system with three load cases are employed. The obtained result by the ACSA compared to that from other methods has revealed that the proposed ACSA is a very promising meata-heuristic algorithm for solving economic emission load dispatch problem.

Prediction of the Spin-Parities and the Magnetic Moments for the Ground States of Proton-rich Nuclei with Z = 21–30

Ly Nguyen Duy,Xayavong Latsamy,Uyen Nguyen Kim,Pham Vinh N. T.,Hao T. V. Nhan,Duy Nguyen Ngoc 한국물리학회 2020 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.77 No.11

The present paper reports on the spin-parities and the magnetic moments for the ground states of 44 proton-rich isotopes with Z = 21-30 and A = 36-57, which are important for studies of either reaction rates in X-ray bursts or nuclear structure. These nuclear properties were calculated based on the single-particle shell model. The spins of the concerned nuclei were compared to available experimental data adopted from the NuDat database to evaluate the variations in the astrophysical rates of the rp-process reactions. We found discrepancies, due to the deformed nuclear structure, between the present results and those reported in the NuDat database. The spin uncertainties result in large variations, 13% - 200%, in the astrophysical rates of the rp-process reactions. In particular, the spin uncertainties of the 44V and the 46-49Mn isotopes significantly affect the astrophysical rates of the reverse reactions of the proton captures 43Ti(p,γ)44V$(p,γ)45Cr, 45Cr(p,γ)46Mn(p,γ)47Fe, 47Mn(p,γ)48Fe, 47Cr(p,γ)48Mn(p,γ)49Fe, and 48Cr(p,γ)49Mn(p,γ)50Fe. Moreover, the magnetic moments of most of the isotopes were predicted for the first time. The results show that the magnetic moments are in the order of μp(1f7/2) > μp(2p3/2) > μn(1d3/2)> μn(1f7/2) for the nuclei having an unpaired nucleon in the proton/neutron shells. The present study suggests that reliable calculations and/or measurements for the properties of proton-rich nuclei are highly demanded.

Catalytic pyrolysis of tulip tree (<i>Liriodendron</i>) in bubbling fluidized-bed reactor for upgrading bio-oil using dolomite catalyst

Ly, Hoang Vu,Lim, Dong-Hyeon,Sim, Jae Wook,Kim, Seung-Soo,Kim, Jinsoo Elsevier 2018 ENERGY Vol.162 No.-

<P><B>Abstract</B></P> <P>Fractional catalytic pyrolysis is an updated pyrolysis method, in which the biomass can be converted into higher quality bio-oil by upgrading the pyrolysis vapor in fluidized bed. In this study, the fast pyrolysis of tulip tree (<I>Liriodendron</I>) was performed in a bubbling fluidized-bed reactor under various reaction conditions (pyrolysis temperature, flow rate of fluidizing medium, and biomass particle size) to investigate the effects of these parameters on product yield and bio-oil quality. The system used silica sand and dolomite as the fluidizing bed material, and nitrogen as the fluidizing medium. When the pyrolysis temperature increased from 400 °C to 550 °C, the bio-oil yield was between 40.07 wt% and 49.03 wt% compared to those of 28.38 and 44.83 wt% using dolomite catalyst. Deoxygenation of bio-oil mostly produced water, and produced lower amounts of CO and CO<SUB>2</SUB>, but higher amounts of H<SUB>2</SUB> and hydrocarbons gas. The catalytic process obtaineda high ratio of H<SUB>2</SUB>/CO in the gas product.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Pyrolysis of tulip tree in fluidized bed reactor under different conditions. </LI> <LI> Catalytic pyrolysis using dolomite catalyst for upgrading bio-oil's quality. </LI> <LI> Dolomite rejected oxygen from pyrolysis vapor, mostly through dehydration. </LI> <LI> The catalytic process produced high H<SUB>2</SUB>/CO ratio in the gas product. </LI> </UL> </P>

Assay of In Vivo Chromium with a Hollow-fiber Dialysis Sensor

Ly, Suw-Young,Yoo, Hai-Soo,Jung, Min-Ki,Ko, Kwang-Hee,Kim, Byung-Jin,Lee, Ki-Chul,Choi, Byung-Min Korean Society of ToxicologyKorea Environmental Mu 2010 Toxicological Research Vol.27 No.3

The analytical in vivo chromium ion was searched for using a voltammetric hollow-fiber dialysis sensor via square wave stripping voltammetry (SW), cyclic voltammetry (CV), and chronoamperometry. Under optimum parameters, the analytical results indicated linear working ranges of 50~400 mg/l CV and $10{\sim}80\;{\mu}g/l$ SW within a 30-sec accumulation time. The analytical detection limit (S/N) was $6.0\;{\mu}g/l$. The developed method can be applied to in vivo tissues and in ex vivo toxicity assay, as well as to other materials that require chromium analysis.