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.

Real-time Assay of Toxic Lead in In Vivo Living Plant Tissue

Ly, SuwYoung,Kim, Nack Joo,Youn, Minsang,Kim, Yongwook,Sung, Yeolmin,Kim, Dohoon,Chung, Tackhyun Korean Society of ToxicologyKorea Environmental Mu 2013 Toxicological Research Vol.29 No.4

A method of detecting lead was developed using square wave anodic stripping voltammetry (SWASV) with DNA-carbon nanotube paste electrode (CNTPE). The results indicated a sensitive oxidation peak current of lead on the DNA-CNTPE. The curves were obtained within a concentration range of 50 $ngL^{-1}-20mgL^{-1}$ with preconcentration time of 100, 200, and 400 sec at the concentration of $mgL^{-1}$, ${\mu}gL^{-1}$, and $ngL^{-1}$, respectively. The observed relative standard deviation was 0.101% (n = 12) in the lead concentration of 30.0 ${\mu}gL^{-1}$ under optimum conditions. The low detection limit (S/N) was pegged at 8 $ngL^{-1}$ ($2.6{\times}10^{-8}M$). Results showed that the developed method can be used in real-time assay in vivo without requiring any pretreatment and pharmaceutical samples, and food samples, as well as other materials requiring water source contamination analyses.

Comparative Efficiency of Container Ports in Vietnam and Korea

Ly, Pham Thi Hoai,Ahn, Ki-Myung,Ryoo, Dong-Keun Korean Institute of Navigation and Port Research 2018 한국항해항만학회지 Vol.42 No.2

Currently, there are very few papers that have examined the efficiency of Vietnamese ports. Of those that have, some of them take into account only a few container ports in Northern Vietnam. Others focus on comparing all types of ports in Vietnam with regard to the differences in efficiency scores when applying different methods to evaluate efficiency. However, there is no paper that specifically analyzes the efficiency of Vietnamese container ports throughout the country or that compares Vietnamese container ports with those of other countries in terms of efficiency. In order to provide more accurate and interesting information for container port authorities, in this study, 21 major Vietnamese container ports and seven major Korean container ports are selected and examined with regard to their levels of efficiency in 2016 using data envelopment analysis (DEA). This paper applies both constant return to scale (CRS) and variable return to scale (VRS) to explore the differences among overall technical efficiency, pure technical efficiency, and scale efficiency of the selected container ports. This study also indicate slacks and sets projections for inefficient ports.

On H\"older estimates for Cauchy transforms on convex domains in $\mathbb{C}^2$

Ly Kim Ha 대한수학회 2019 대한수학회보 Vol.56 No.4

The main purpose of this paper is to establish H\"older estimates for the Cauchy transform in a class of finite/infinite type convex domains in $\mathbb{C}^2$.

A note on zeros of bounded holomorphic functions in weakly pseudoconvex domains in C2

Ly Kim Ha 대한수학회 2017 대한수학회보 Vol.54 No.3

Let $\Omega$ be a bounded, uniformly totally pseudoconvex domain in $\mathbb{C}^2$ with the smooth boundary $b\Omega$. Assuming that $\Omega$ satisfies the negative $\bar\partial$ property. Let $M$ be a positive, finite area divisor of $\Omega$. In this paper, we will prove that: if $\Omega$ admits a maximal type $F$ and the $\rm \check{C}$eck cohomology class of the second order vanishes in $\Omega$, there is a bounded holomorphic function in $\Omega$ such that its zero set is $M$. The proof is based on the method given by Shaw \cite{Sha89}.

Effects of COD/N ratio on soluble microbial products in effluent from sequencing batch reactors and subsequent membrane fouling

Ly, Quang Viet,Nghiem, Long D.,Sibag, Mark,Maqbool, Tahir,Hur, Jin Elsevier 2018 Water research Vol.134 No.-

<P><B>Abstract</B></P> <P>The relative ratios of chemical oxygen demand (COD) to nitrogen (N) in wastewater are known to have profound effects on the characteristics of soluble microbial products (SMP) from activated sludge. In this study, the changes in the SMP characteristics upon different COD/N ratios and the subsequent effects on ultrafiltration (UF) membrane fouling potentials were examined in sequencing batch reactors (SBR) using excitation emission matrix-parallel factor analysis (EEM-PARAFAC) and size exclusion chromatography (SEC). Three unique fluorescent components were identified from the SMP samples in the bioreactors operated at the COD/N ratios of 100/10 (N rich), 100/5 (N medium), and 100/2 (N deficient). The tryptophan-like component (C1) was the most depleted at the N medium condition. Fulvic-like (C2) and humic-like (C3) components were more abundant with N rich wastewater. Greater abundances of large size biopolymer (BP) and low molecular weight neutrals (LMWN) were found under the N deficient and N rich conditions, respectively. SMPs from various COD/N exhibited a greater degree on membrane fouling following the order of 100/2 > 100/10 > 100/5. C1 and C2 had close associations with reversible and irreversible fouling, respectively, while the reversible fouling potential of C3 depended on the COD/N ratios. No significant impact of COD/N ratio was observed on the relative contributions of SMP size fractions to either reversible or irreversible fouling potential. However, the COD/N ratios likely altered the BP foulants' composition with greater contribution of proteinaceous substances to reversible fouling under the N deficient condition than at other N richer conditions. The opposite trend was observed for irreversible fouling. Our results provided further insight into changes in different SMP constitutes and their membrane fouling in response to microbial activities under different COD/N ratios.</P> <P><B>Highlights</B></P> <P> <UL> <LI> EEM-PARAFAC and SEC evidenced the changes in SMP composition at varying COD/N. </LI> <LI> Humic-like substances are more abundant with N enrichment. </LI> <LI> SMP's membrane fouling characteristics are highly dependent on COD/N ratios. </LI> <LI> Humic-like FDOM make more contribution to reversible fouling at lower COD/N. </LI> <LI> It provides insight into COD/N-dependent SMP and the effects on fouling behavior. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Ex Vivo Assay of Trace Nicotine Using a Voltammetric Modified Biosensor

Ly, Suw Young,Jang, Myung-Ho,Cha, Jae-Min,Kim, Min-Young,Oh, Hyun-Seok,Jo, Dong-Hyeon,Choi, Seong-Sik The Korean Society of Applied Science and Technolo 2012 한국응용과학기술학회지 Vol.29 No.1

In vivo nicotine is associated with Alzheimer's, Parkinson's and lung cancer. Diagnostic assays of these diseases depend on very low analytical detection limits. In this study, a sensitive analytical method was examined using a voltammetric graphite pencil electrode (GPE) and a modified carbon nanotube paste electrode (CNE). The optimum analytical conditions for both electrodes were compared using square wave anodic stripping voltammetry (SW) and cyclic voltammetry (CV) obtaining 400 sec accumulation time and oxidation peak. Under optimum parameters, the stripping working range of GPE was $5.0-40.0{\mu}g/L$, CNE: 0.1-0.8 and $5-50{\mu}g/L$. Quantification limits were $5.0{\mu}g/L$ for GPE and $0.1{\mu}g/L$ for CNE, while detection limits were $0.6{\mu}g/L$ for GPE and $0.07{\mu}g/L$ for CNE. A standard deviation of $10.0{\mu}g/L$ was observed for 0.064 GPE and 0.095 CNE (n = 12) using 400 sec accumulation time. The results obtained can be applied to non.treated urine and ex vivo biological diagnostics.

The Politics of the Pot: Contemporary Cambodian Women Artists Negotiating Their Roles In and Out of the Kitchen

Ly, Boreth Korea Institute for ASEAN Studies 2020 Suvannabhumi Vol.12 No.1

Two utilitarian and symbolic objects associated with womanhood in Cambodian culture are the stove and the pot. The pot is a symbol of both the womb and female sexuality; the stove is a symbol of gendered feminine labor. This article argues that the sexist representations of the Khmer female body by modern Cambodian male artists demonstrate an inherited legacy of Orientalist stereotypes. These images were formed : under French colonialism and often depict Khmer women as erotic/exotic native Others. Starting in the 1970s, however, if not earlier, Cambodian women began to question the gendering of social roles that confined them to domestic space and labor. This form of social questioning was especially present in pop songs. In recent years, contemporary Cambodian woman artists such as Neak Sophal and Tith Kanitha have made use of rice pots and stoves in their art as freighted symbols of femininity. Neak created an installation of rice pots from different households in their village, while Tith rebelled against this gendered role by destroying cooking stoves as an act of defiance against patriarchy in her performance art.

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.