Novel anti-apoptotic mechanism of A20 through targeting ASK1 to suppress TNF-induced JNK activation

Won, M,Park, K A,Byun, H S,Sohn, K-C,Kim, Y-R,Jeon, J,Hong, J H,Park, J,Seok, J H,Kim, J M,Yoon, W-H,Jang, I-S,Shen, H M,Liu, Z G,Hur, G M Macmillan Publishers Limited 2010 CELL DEATH AND DIFFERENTIATION Vol.17 No.12

The zinc-finger protein A20 has crucial physiological functions as a dual inhibitor of nuclear factor-κB (NF-κB) activation and apoptosis in tumor necrosis factor (TNF) receptor 1 signaling pathway. Although the molecular basis for the anti-NF-κB function of A20 has been well elucidated, the anti-apoptotic function of A20 is largely unknown. Here, we report a novel mechanism underlying the anti-apoptotic function of A20: A20 blocks TNF-induced apoptosis through suppression of c-jun N-terminal kinase (JNK) by targeting apoptosis signal-regulating kinase1 (ASK1). First, the ectopic expression of A20 drastically inhibits TNF-induced JNK activation and apoptosis in multiple cell types including those deficient of NF-κB activation. Unexpectedly, the blunting effect of A20 on TNF-induced JNK activation is not mediated by affecting the TNFR1 signaling complex formation. Instead, A20 interacts with ASK1, an important MAPKK kinase in the JNK signaling cascade. More importantly, overexpression of wild-type A20, but not of mutant A20 (ZnF4; C624A, C627A), promotes degradation of the ASK1 through the ubiquitin-proteasome system. Taken together, the results from this study reveal a novel anti-apoptotic mechanism of A20 in TNF signaling pathway: A20 binds to ASK1 and mediates ASK1 degradation, leading to suppression of JNK activation and eventually blockage of apoptosis.

Distribution of Glutathione S-Transferase Omega Gene Polymorphism with Different Stages of HBV Infection Including Hepatocellular Carcinoma in the Egyptian Population

Shaban, Nadia Z,Salem, Halima H,Elsadany, Mohamed A,Ali, Bahy A,Hassona, Ehab M,Mogahed, Fayed AK Asian Pacific Journal of Cancer Prevention 2016 Asian Pacific journal of cancer prevention Vol.17 No.4

Background: Infection with hepatitis B virus (HBV) is a major global public health problem, with a wide spectrum of clinical manifestations. Human cytosolic glutathione-S-transferases (GSTs) include several classes such as alpha (A), mu (M), pi (P), sigma (S), zeta (Z), omega (O) and theta (T). The present study aimed to investigate the role of GST omega genes (GSTO1 and GSTO2) in different groups of patients infected with HBV. Materials and Methods: HBV groups were classified according to clinical history, serological tests and histological analysis into normal carriers (N), acute (A), chronic (CH), cirrhosis (CI) and hepatocellular carcinoma (HCC) cases. The study focused on determination of the genotypes of GST omega genes (GSTO1 and GSTO2) and GST activity and liver function tests. Results: The results showed that GSTO1 (A/A) was decreased in N, A, CH, CI and HCC groups compared to the C-group, while, GSTO1 (C/A) and GSTO1(C/C) genotypes were increased significantly in N, A, CH, CI and HCC groups. GSTO2 (A/A) was decreased in all studied groups as compared to the C-group but GSTO2(A/G) and GSTO2(G/G) genotypes were increased significantly. In addition, GST activities, albumin and TP levels were decreased in all studied groups compared to the C-group, while the activities of transaminases were increased to differing degrees. Conclusions: The results indicate that GSTO genetic polymorphisms may be considered as biomarkers for determining and predicting the progression of HBV infection.

Red organic light-emitting diodes with high efficiency, low driving voltage and saturated red color realized via two step energy transfer based on ADN and Alq3 co-host system

Khizar-ul Haq,Liu Shan-peng,M.A. Khan,X.Y. Jiang,Z.L. Zhang,Jin Cao,W.Q. Zhu 한국물리학회 2009 Current Applied Physics Vol.9 No.1

We demonstrated efficient red organic light-emitting diodes based on a wide band gap material 9,10-bis(2-naphthyl)anthracene (ADN) doped with 4-(dicyano-methylene)-2-t-butyle-6-(1,1,7,7-tetramethyl-julolidyl-9-enyl)-4H-pyran (DCJTB) as a red dopant and 2,3,6,7-tetrahydro-1,1,7,7,-tetramethyl-1H,5H,11H-10(2-benzothiazolyl)quinolizine-[9,9a,1gh]coumarin (C545T) as an assistant dopant. The typical device structure was glass substrate/ITO/4,4',4''-tris(N-3-methylphenyl-N-phenyl-amino)triphenylamine (m-MTDATA)/ N,N'-bis(naphthalene-1-yl)-N,N0-diphenyl-benzidine (NPB)/[ADN:Alq3]:DCJTB:C545T/Alq3/LiF/Al. It was found that C545T dopant did not by itself emit but did assist the energy transfer from the host (ADN) to the red emitting dopant via cascade energy transfer mechanism. The OLEDs realized by this approach significantly improved the EL efficiency. We achieved a significant improvement regarding saturated red color when a polar co-host emitter (Alq3) was incorporated in the matrix of [ADN:Alq3]. Since ADN possesses a considerable high electron mobility of 3.1 × 10-4 ㎠ V-1 s-1, co-host devices with high concentration of ADN (>70%) exhibited low driving voltage and high current efficiency as compared to the devices without ADN. We obtained a device with a current efficiency of 3.6 cd/A, Commission International d’Eclairage coordinates of [0.618, 0.373] and peak λmax = 620 nm at a current density of 20 mA/㎠. This is a promising way of utilizing wide band gap material as the host to make red OLEDs, which will be useful in improving the electroluminescent performance of devices and simplifying the process of fabricating full color OLEDs. We demonstrated efficient red organic light-emitting diodes based on a wide band gap material 9,10-bis(2-naphthyl)anthracene (ADN) doped with 4-(dicyano-methylene)-2-t-butyle-6-(1,1,7,7-tetramethyl-julolidyl-9-enyl)-4H-pyran (DCJTB) as a red dopant and 2,3,6,7-tetrahydro-1,1,7,7,-tetramethyl-1H,5H,11H-10(2-benzothiazolyl)quinolizine-[9,9a,1gh]coumarin (C545T) as an assistant dopant. The typical device structure was glass substrate/ITO/4,4',4''-tris(N-3-methylphenyl-N-phenyl-amino)triphenylamine (m-MTDATA)/ N,N'-bis(naphthalene-1-yl)-N,N0-diphenyl-benzidine (NPB)/[ADN:Alq3]:DCJTB:C545T/Alq3/LiF/Al. It was found that C545T dopant did not by itself emit but did assist the energy transfer from the host (ADN) to the red emitting dopant via cascade energy transfer mechanism. The OLEDs realized by this approach significantly improved the EL efficiency. We achieved a significant improvement regarding saturated red color when a polar co-host emitter (Alq3) was incorporated in the matrix of [ADN:Alq3]. Since ADN possesses a considerable high electron mobility of 3.1 × 10-4 ㎠ V-1 s-1, co-host devices with high concentration of ADN (>70%) exhibited low driving voltage and high current efficiency as compared to the devices without ADN. We obtained a device with a current efficiency of 3.6 cd/A, Commission International d’Eclairage coordinates of [0.618, 0.373] and peak λmax = 620 nm at a current density of 20 mA/㎠. This is a promising way of utilizing wide band gap material as the host to make red OLEDs, which will be useful in improving the electroluminescent performance of devices and simplifying the process of fabricating full color OLEDs.

Harmonic decomposition of two particle angular correlations in Pb-Pb collisions at s_NN=2.76 TeV

ALICE Collaboration,Aamodt, K.,Abelev, B.,Abrahantes Quintana, A.,Adamova, D.,Adare, A.M.,Aggarwal, M.M.,Aglieri Rinella, G.,Agocs, A.G.,Agostinelli, A.,Aguilar Salazar, S.,Ahammed, Z.,Ahmad, N.,Ahmad North-Holland Pub. Co 2012 Physics letters: B Vol.708 No.3

Angular correlations between unidentified charged trigger (t) and associated (a) particles are measured by the ALICE experiment in Pb-Pb collisions at s<SUB>NN</SUB>=2.76 TeV for transverse momenta 0.25<p<SUB>T</SUB><SUP>t,a</SUP><15 GeV/c, where p<SUB>T</SUB><SUP>t</SUP>>p<SUB>T</SUB><SUP>a</SUP>. The shapes of the pair correlation distributions are studied in a variety of collision centrality classes between 0 and 50% of the total hadronic cross section for particles in the pseudorapidity interval |η|<1.0. Distributions in relative azimuth Δφ=φ<SUP>t</SUP>-φ<SUP>a</SUP> are analyzed for |Δη|=|η<SUP>t</SUP>-η<SUP>a</SUP>|>0.8, and are referred to as ''long-range correlations''. Fourier components V<SUB>nΔ</SUB>≤cos(nΔφ)> are extracted from the long-range azimuthal correlation functions. If particle pairs are correlated to one another through their individual correlation to a common symmetry plane, then the pair anisotropy V<SUB>nΔ</SUB>(p<SUB>T</SUB><SUP>t</SUP>,p<SUB>T</SUB><SUP>a</SUP>) is fully described in terms of single-particle anisotropies v<SUB>n</SUB>(p<SUB>T</SUB>) as V<SUB>nΔ</SUB>(p<SUB>T</SUB><SUP>t</SUP>,p<SUB>T</SUB><SUP>a</SUP>)=v<SUB>n</SUB>(p<SUB>T</SUB><SUP>t</SUP>)v<SUB>n</SUB>(p<SUB>T</SUB><SUP>a</SUP>). This expectation is tested for 1≤n≤5 by applying a global fit of all V<SUB>nΔ</SUB>(p<SUB>T</SUB><SUP>t</SUP>,p<SUB>T</SUB><SUP>a</SUP>) to obtain the best values v<SUB>n</SUB>{GF}(p<SUB>T</SUB>). It is found that for 2≤n≤5, the fit agrees well with data up to p<SUB>T</SUB><SUP>a</SUP>~3-4 GeV/c, with a trend of increasing deviation as p<SUB>T</SUB><SUP>t</SUP> and p<SUB>T</SUB><SUP>a</SUP> are increased or as collisions become more peripheral. This suggests that no pair correlation harmonic can be described over the full 0.25<p<SUB>T</SUB><15 GeV/c range using a single v<SUB>n</SUB>(p<SUB>T</SUB>) curve; such a description is however approximately possible for 2≤n≤5 when p<SUB>T</SUB><SUP>a</SUP><4 GeV/c. For the n=1 harmonic, however, a single v<SUB>1</SUB>(p<SUB>T</SUB>) curve is not obtained even within the reduced range p<SUB>T</SUB><SUP>a</SUP><4 GeV/c.

Fatigue crack effect on magnetic flux leakage for A283 grade C steel

M.I.M. Ahmad,A. Arifin,S. ABDULLAH,W.Z.W. Jusoh,S.S.K. Singh 국제구조공학회 2015 Steel and Composite Structures, An International J Vol.19 No.6

This paper presents the characterization of fatigue crack in the A283 Grade C steel using the MMM method by identifying the effects of magnetic flux leakage towards the crack growth rate, da/dN, and crack length.The previous and current research on the relation between MMM parameters and fatigue crack effect is still unclear and requires specific analysis to validate that. This method is considered to be a passive magnetic method among other Non-Destructive Testing (NDT) methods. The tension-tension fatigue test was conducted with a testing frequency of 10 Hz with 4 kN loaded, meanwhile the MMM response signals were captured using a MMM instrument. A correlation between the crack growth rate and magnetic flux leakage produces a sigmoid shape curve with a constant values which present the gradient, m value is in the ranges of 1.4357 to 4.0506, and the y-intercept, log C in the ranges of 4×10<SUP>-7</SUP> to 0.0303. Moreover, a linear relation was obtained between the crack length and magnetic flux leakage which present the R-Squared values is at 0.830 to 0.978. Therefore, MMM method has their own capability to investigate and characterize the fatigue crack effects as a main source of fracture mechanism for ferrous-based materials.

Fabrication process of a microstructures based on hydrogenated amorphous SiGe films for applications in MEMS devices

M. Galindo-Mentle,F. López-Huerta,R. Palomino-Merino,C. Zúñiga-Islas,W. Calleja-Arriaga,A. L. Herrera-May 대한기계학회 2015 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.29 No.4

We present a fabrication process of microstructures using both boron-doped hydrogenated amorphous silicon and hydrogenated amorphoussilicon-germanium (a-SiB:H and a-Si0.5Ge0.5B:H) films for applications in devices based on microelectromechanical systems(MEMS). These microstructures are fabricated through plasma enhanced chemical vapor deposition (PECVD) with a low temperature of300°C at 110 kHz and a pressure of 0.6 Torr. The proposed microstructures have three different geometries (Diamond, cantilever andbridge) considering a single structural layer of 1 μm thickness and are fabricated using surface micromachining. The fabricated a-Si0.5Ge0.5B:H microstructures do not present sticking problems and have good mechanical stability, which can allow their use in MEMSdevices. Our fabrication process with hydrogenated amorphous SiGe films is simple. This process decreases the residual stress of themicrostructures and allows the metal deposition on the microstructures surfaces.

Strength of Thixoformed A319 Alloy at Elevated Temperature

A. M. Aziz,M. Z. Omar,Z. Sajuri 대한금속·재료학회 2021 METALS AND MATERIALS International Vol.27 No.7

When alloys are exposed to elevated temperatures they experience a decrement in their mechanical properties that leadsto material failure. However, the use of thixoforming, an alternative metal processing method, could enhance mechanicalproperties by minimising the defects that exist in as-received alloys. Therefore, this study aimed to determine the tensilestrength of thixoformed A319 under elevated temperatures by taking into account its intended use in vehicle cylinder headcomponents. Thixoformed A319 was compared with as-received alloy manufactured by permanent mould casting. Thecooling slope method was used to prepare the feedstock for thixoforming. The feedstock was reheated by induction heatinguntil it reached 574 °C and was then formed in a mould. Afterwards, the as-received and thixoformed samples underwentT6 heat treatment. The resulting samples were characterised by using optical microscopy, scanning electron microscopyequipped with energy dispersive X-ray, X-ray difraction analysis and a tensile test. Elevated temperature tensile tests wereperformed at 250 °C, in line with the temperature condition experienced by cylinder head components during operation. The ultimate tensile strength of the thixoformed samples was 30% higher than that of the as-received samples under elevatedtemperatures. Also, the analyses of the fracture surfaces showed that porosity, intermetallic compounds and impurities wereamongst the failure factors for both alloys.

Modeling of transient and steady-state dark current in amorphous silicon p–i–n photodiodes

S.A. Mahmood,M.Z. Kabir 한국물리학회 2009 Current Applied Physics Vol.9 No.6

A theoretical model for describing the bias-dependent transient and steady-state behavior of dark current in hydrogenated amorphous silicon (a-Si:H) p–i–n photodiode has been developed. An analytical expression for the bias-dependent steady-state thermal generation current is derived by solving the continuity equations for both electrons and holes. The model for describing transient dark current in a-Si:H p–i–n photodiode is developed by considering the depletion of electrons from the i-layer and carrier injection through p–i interface. For photodiodes that have very good junction properties, the high initial dark current decreases with time monotonously and reaches a plateau. However, in case of poor junctions, the injection current can be the dominating mechanism for transient leakage current at relatively high biases, the dark current decays initially and then rises to a steady-state value. The proposed physics-based dark current model is compared with published experimental results on several photodiodes. The comparison of the model with the experimental data allows an estimate of active dopant concentration in the p-layer and the defect density in the midgap of i-layer. A theoretical model for describing the bias-dependent transient and steady-state behavior of dark current in hydrogenated amorphous silicon (a-Si:H) p–i–n photodiode has been developed. An analytical expression for the bias-dependent steady-state thermal generation current is derived by solving the continuity equations for both electrons and holes. The model for describing transient dark current in a-Si:H p–i–n photodiode is developed by considering the depletion of electrons from the i-layer and carrier injection through p–i interface. For photodiodes that have very good junction properties, the high initial dark current decreases with time monotonously and reaches a plateau. However, in case of poor junctions, the injection current can be the dominating mechanism for transient leakage current at relatively high biases, the dark current decays initially and then rises to a steady-state value. The proposed physics-based dark current model is compared with published experimental results on several photodiodes. The comparison of the model with the experimental data allows an estimate of active dopant concentration in the p-layer and the defect density in the midgap of i-layer.

Effect of Lubricant with Nanodiamond Particles in Sliding Friction

M. H. Adzaman,A. Rahman,Y. Z. Lee,S. S. Kim 한국트라이볼로지학회 2015 한국윤활학회지(윤활학회지) Vol.31 No.4

This paper presents the experimental effects of lubricant with nanodiamond particles in sliding friction. In order to improve the performance of lubricants many additives are used, such as MoS2, cadmium chloride, indium, sulfides, and phosphides. These additives are harmful to human health and to the environment, so alternatives are necessary. One such alternative is nanodiamond powder, which has a large surface area. In order to investigate the effect of nanodiamonds in lubricants under sliding friction, they are dispersed in the lubricant at a variety of concentrations (0 wt%, 0.1 wt%, 0.3 wt%, 0.5 wt%, and 1 wt%) using the matrix synthesis method. Friction and wear tests are performed according to the ASTM G99 method using a pin-on-disc tester at room temperature. The specimens used in this experiment are AISI 52100 ball bearings and AISI 1020 steel discs. During the test, lubricant mixed with nanodiamond is supplied constantly to keep the two bodies separated by a lubricant film. To maintain boundary lubrication, the speed is set to 0.18 m/s and a load of 294 N is applied to the disc through the pin. Results are recorded by using workbench software over the test duration of 10 minutes. Experimental results show that when the concentration of nanodiamond increases, the coefficient of friction decreases. However, above a nanodiamond concentration of 0.5 wt%, both the coefficient of friction and wear volume increase. From this experiment, the optimum concentration of nanodiamond showing a minimum coefficient of friction of 0.09 and minimum wear volume of 0.82 nm2 was 0.5 wt%.

Activation of molecular oxygen for the oxidation of 2-mercaptoethanol: A kinetic and mechanistic approach

M.Z.A. Rafiquee,Masoom R. Siddiqui,H.N. Haque,M. Shamsul Ola,Hamad A. Al-Lohedan,Z.A. ALOthman,Saikh M. Wabaidur 한국공업화학회 2016 Journal of Industrial and Engineering Chemistry Vol.34 No.-

Reduction of molecular oxygen by 2-mercaptoethanol in the presence of cobalt(II)histidine is described. Cobalt(II)histidine complex forms dinuclear 2:1 (Co:O2) complex with molecular oxygen (m-dioxyte-trakis(histidinato)dicobalt(II)). The molecular oxygen did not directly react with 2-mercaptoethanol, but,reacted in the form of an adduct with cobalt(II)histidine complex. During the course of the reaction themolecular oxygen is reduced to hydroxide ion while the cobalt(II)histidine complex was oxidized tocobalt(III)histidine while 2-mercaptoethanol is reduced into 2,20-dithiodiethanol. The decrease inabsorbance for the dioxygen complex was monitored spectrophotometrically and was observed that thevalues of rate constant increased with the increase in [2-mercaptoethanol]. The values of kobs also increasedwith increasing [NaOH]. Thus, from the results of these studies, mechanism of the reaction has beenproposed. In addition, the values of various equilibrium constants and rate constants were also determinedusing nonlinear least square techniques.