Twinstar/cofilin is required for regulation of epithelial integrity and tissue growth in Drosophila

Ko, C,Kim, Y-G,Le, T P,Choi, K-W Macmillan Publishers Limited 2016 Oncogene Vol.35 No.39

<P>Regulation of actin assembly and depolymerization is important for the organization of epithelia. Recent studies have shown that the actin-capping proteins are required to prevent cell extrusion and inappropriate activation of Yorkie (Yki) activity in Drosophila, implicating the importance of actin regulation for epithelial integrity and Yki-dependent tissue growth. However, the role of Twinstar (Tsr), the Drosophila homolog for cofilin/actin depolymerization factor (ADF), in epithelial integrity and Hippo signaling is unknown. Here we demonstrate that reduction of Tsr by RNA interference (RNAi) or mutant clones in wing imaginal disc induces not only F-actin accumulation but also ectopic expression of Wingless (Wg) and Yki target gene expanded (ex). Knockdown of Yki in Tsr-depleted cells reduced the level of ectopic Wg expression. Reduced Tsr also led to downregulation of cell junction proteins and extrusion of affected cells from the basal part of the epithelium. Rho GTPase 1 was upregulated in Tsr-depleted tissue, supporting the Tsr function in the inhibition of cell extrusion from the epithelium. Tsr is also required for blocking cell death and c-Jun N-terminal kinase (JNK) signaling. Ectopic JNK activation induced caspase activation but did not cause cell extrusion. Further, the invasiveness of Tsr-depleted cells was not suppressed by inhibition of cell death or JNK signaling. In contrast, Yki upregulation was significantly suppressed by cell death inhibition. Taken together, our data suggest that Tsr is required for cell survival and tissue growth by regulating JNK and Yki signaling while maintaining the epithelial integrity by controlling cell junctions. This study provides an insight into potential roles of ADF/cofilin in invasive cell migration and tumor suppression in higher animals.</P>

ON PSEUDO 2-PRIME IDEALS AND ALMOST VALUATION DOMAINS

Koc, Suat Korean Mathematical Society 2021 대한수학회보 Vol.58 No.4

In this paper, we introduce the notion of pseudo 2-prime ideals in commutative rings. Let R be a commutative ring with a nonzero identity. A proper ideal P of R is said to be a pseudo 2-prime ideal if whenever xy ∈ P for some x, y ∈ R, then x²ⁿ ∈ Pⁿ or y²ⁿ ∈ Pⁿ for some n ∈ ℕ. Various examples and properties of pseudo 2-prime ideals are given. We also characterize pseudo 2-prime ideals of PID's and von Neumann regular rings. Finally, we use pseudo 2-prime ideals to characterize almost valuation domains (AV-domains).

Histological analysis of acute toxicity of 2,4-diclorophenoxy acetic acid in ovary of zebrafish

Koc, Nazan Deniz,Akbulut, Cansu The Korean Society for Integrative Biology 2012 Animal cells and systems Vol.16 No.5

Plant growth regulators are the chemicals that are found in plants and produced synthetically. In agricultural applications, plant hormones are used in minor quantities for fixing the problems. In our research, we studied the effects of 2,4 diclorophenoxyacetic acid (2,4D), which is an auxin used in agricultural applications. Auxins are the group that are used most popularly in plant growth regulators. In our study, different doses of 2,4 diclorophenoxyacetic acid are given to zebrafish, and ovarium tissues are observed histomorphologically. We generated one control and three experiment groups from the stock solution. The experiment was carried out in 20 liter capacity complete glass aquarium at $24{\pm}1^{\circ}C$ water temperature. After five days of application, fishes were dissected. Histomorphological changes of the ovarium were investigated under a light microscope. A decrease in the number of oocytes in zebrafish ovarium was observed when compared with the control group. Many deformed and underdeveloped oocytes were detected. An increase in the number of atretic oocytes was observed. It was deduced that acute doses of 2,4 diclorophenoxyacetic acid decelerates oogenesis in fishes.

NOTES ON IDEALS AND ORTHOGONAL GENERALIZED ($\sigma$, $\tau$)-DERIVATIONS

Koc, Emine The Youngnam Mathematical Society Korea 2008 East Asian mathematical journal Vol.24 No.4

In this paper, some results of [6] concerning orthogonal ($\sigma$, $\tau$)-derivations and generalized ($\sigma$, $\tau$)-derivations are generalized for a nonzero ideal of a semiprime ring.

Delayed Aneurysm Rupture Following Endovascular Treatment with Contour Device: A Case Report

Koc Osman,Mahmoud Mostafa,Mahmoud Ehab,Ayyad Ali,Own Ahmad 대한신경중재치료의학회 2025 Neurointervention Vol.20 No.1

Delayed rupture of intracranial aneurysms after endovascular treatment is a rare but serious complication. We report the first documented case of late aneurysmal rupture following treatment with a Contour intrasaccular device. A patient in their 60s with a basilar tip aneurysm underwent endovascular treatment using a 14-mm Contour device. Fifteen months later, the patient presented with a fatal intraventricular hemorrhage, and imaging revealed device displacement and aneurysm growth. This case underscores the importance of meticulous device sizing and follow-up, especially for large aneurysms.

ON STRONGLY QUASI PRIMARY IDEALS

Koc, Suat,Tekir, Unsal,Ulucak, Gulsen Korean Mathematical Society 2019 대한수학회보 Vol.56 No.3

In this paper, we introduce strongly quasi primary ideals which is an intermediate class of primary ideals and quasi primary ideals. Let R be a commutative ring with nonzero identity and Q a proper ideal of R. Then Q is called strongly quasi primary if $ab{\in}Q$ for $a,b{\in}R$ implies either $a^2{\in}Q$ or $b^n{\in}Q$ ($a^n{\in}Q$ or $b^2{\in}Q$) for some $n{\in}{\mathbb{N}}$. We give many properties of strongly quasi primary ideals and investigate the relations between strongly quasi primary ideals and other classical ideals such as primary, 2-prime and quasi primary ideals. Among other results, we give a characterization of divided rings in terms of strongly quasi primary ideals. Also, we construct a subgraph of ideal based zero divisor graph ${\Gamma}_I(R)$ and denote it by ${\Gamma}^*_I(R)$, where I is an ideal of R. We investigate the relations between ${\Gamma}^*_I(R)$ and ${\Gamma}_I(R)$. Further, we use strongly quasi primary ideals and ${\Gamma}^*_I(R)$ to characterize von Neumann regular rings.

The use of liquefied petroleum gas (lpg) and natural gas in gas turbine jet engines

Koc, Ibrahim Techno-Press 2015 Advances in energy research Vol.3 No.1

This paper compares the performance of JP-8(Jet Propellant) fuel and liquefied petroleum gas (LPG) and natural gas in the F110 GE100 jet engine. The cost of natural gas usage in gas turbine engines is lower than JP-8 and LPG. LPG cost is more than JP-8. LPG volume is bigger than JP-8 in the same flight conditions. Fuel tank should be cryogenic for using natural gas in the aircraft. Cost and weight of the cryogenic tanks are bigger. Cryogenic tanks decrease the move capability of the aircraft. The use of jet propellant (JP) is the best in available application for F110 GE 100 jet engine.

NOTES ON SYMMETRIC SKEW n-DERIVATION IN RINGS

Koc, Emine,Rehman, Nadeem ur Korean Mathematical Society 2018 대한수학회논문집 Vol.33 No.4

Let R be a prime ring (or semiprime ring) with center Z(R), I a nonzero ideal of R, T an automorphism of $R,S:R^n{\rightarrow}R$ be a symmetric skew n-derivation associated with the automorphism T and ${\Delta}$ is the trace of S. In this paper, we shall prove that S($x_1,{\ldots},x_n$) = 0 for all $x_1,{\ldots},x_n{\in}R$ if any one of the following holds: i) ${\Delta}(x)=0$, ii) [${\Delta}(x),T(x)]=0$ for all $x{\in}I$. Moreover, we prove that if $[{\Delta}(x),T(x)]{\in}Z(R)$ for all $x{\in}I$, then R is a commutative ring.

Numerical and Experimental Investigations on Deformation Behavior of Aluminum 5754 Sheet Alloy under Warm Hydroforming Conditions

M. Koc,S. Mahabunphachai,J.E. Carsley 한국소성가공학회 2010 기타자료 Vol.2010 No.6

Material behavior of Al5754 was characterized using both tensile and hydraulic bulge tests under both room and warm temperature conditions. Response of Al5754 to different process conditions such as pressurization rates (0.022 and 0.2s<SUP>-1</SUP> strain rate), variable strain rates (increasing and decreasing profiles), forming temperature (room to 260℃), and loading conditions (uniaxial vs. biaxial) were presented. The results from tensile and hydraulic bulge tests as well as closed-die hydroforming experiments suggested that, in general, formability of Al5754 could be improved with slow forming rates (<0.02s<SUP>-1</SUP>), high forming temperature (>200℃), and biaxial loading (hydoforming) due to the delay of necking. However, decreasing forming rate conditions did not show any improvement in formability for temperature levels below 200℃.

Comparison of the Classical Method and SEE-FIM Protocol in Detecting Microscopic Lesions in Fallopian Tubes with Gynecological Lesions

Nermin Koc,Selçuk Ayas,Sevcan Arzu Arinkan 대한병리학회 2018 Journal of Pathology and Translational Medicine Vol.52 No.1

Background: The objective of this study was to compare the classical method and Sectioning and Extensively Examining the Fimbriated End Protocol (SEE-FIM) in detecting microscopic lesions in fallopian tubes with gynecological lesions. Methods: From a total of 1,118 cases, 582 with various parts of both fallopian tubes sampled in three-ring-shape sections and 536 sampled with the SEE-FIM protocol were included in this study. Pathological findings of cases with endometrial carcinoma, non-uterine pelvic malignant tumor, ovarian borderline tumors, premalignancy, and benign lesions were compared. Results: We detected two tubal infiltrative carcinomas among 40 uterine endometrioid adenocarcinomas, 15 serous tubal intraepithelial carcinomas in 39 non-uterine pelvic serous high-grade carcinoma cases, seven papillary tubal hyperplasias in 13 serous borderline tumor cases, and 11 endometriotic foci and four adenomatoid tumors among all cases sampled with the SEE-FIM protocol. Using the classical method, we detected only one serous tubal intraepithelial carcinoma in 113 non-uterine pelvic serous high-grade carcinoma cases and two papillary tubal hyperplasia cases in 31 serous borderline tumors. We did not identify additional findings in 185 uterine endometrioid carcinoma cases, and neither endometriotic focus nor adenomatoid tumor was shown in other lesions by the classical method. Conclusions: Benign, premalignant, and malignant lesions can possibly be missed using the classical method. The SEE-FIM protocol should be considered especially in cases of endometrial carcinoma, nonuterine pelvic serous cancers, or serous borderline ovarian tumors. For other lesions, at least a detailed examination of the fimbrial end should be undertaken.