The Influence of Hydrogen Addition to Argon as a Shielding Gas on the Fatigue Performance of TIG Welded AISI 304 Stainless Steel

In this study, AISI 304 austenitic stainless steel sheets are joined through TIG welding under various shielding media. Bending fatigue, notch impact and bending tests are performed on the joined materials. Hardness of the joined materials is also determined. The welding processes are carried using pure argon, argon + 1.5% H₂ and argon + 5% H₂ as shielding media at three different welding currents. Both butt and overlap welding processes are carried out at the same welding parameters. The ER 308 L type wire is used as the filler material for all the joints. The highest fatigue and impact strengths are obtained for both types of joints for argon shielding media. The bending test is applied up to 180°, and no tearing, crack or any other bending defects after visual examination of the bended samples are observed. The welding metal gives the highest hardness values, and they are followed by HAZ and base material.У даному дослідженні листи неіржавійної аустенітної сталі AISI 304 з’єднувалися газовольфрамовим дуговим зварюванням у середовищі різних захисних газів. З’єднані матеріали були піддані тестам на вигин, утомним випробуванням на вигин та випробуванням на ударний вигин із розрізом. Визначалася також твердість з’єднаних матеріалів. Процеси зварювання виконувалися з використанням чистого арґону, арґону + 1,5% H₂ та арґону + 5% H₂ як захисних середовищ при трьох різних струмах зварювання. Виконувалося як зварювання зі стиком упритул, так і внапусток при однакових параметрах зварювання. Для всіх зварних швів як присаджувальний матеріал використовувався дріт типу ER 308 L. Для обох типів швів найбільша утомна і ударна міцності були одержані при використанні арґонового захисного середовища. Випробування на вигин виконувалися до значень кута вигину у 180°; при цьому на зігнутих зразках візуально не спостерігалося жодних розривів, тріщин та будь-яких інших дефектів вигину. Зварюваний метал мав найвищу твердість як у пришовній зоні, так і в основному матеріалі.В данном исследовании листы нержавеющей аустенитной стали AISI 304 соединялись газовольфрамовой дуговой сваркой в среде различных защитных газов. Соединённые материалы были подвергнуты тестам на изгиб, усталостным испытаниям на изгиб и испытаниям на ударный изгиб с разрезом. Определялась также твёрдость соединённых материалов. Процессы сварки производились с использованием чистого аргона, аргона + 1,5% H₂ и аргона + 5% H₂ в качестве защитных сред при трёх разных токах сварки. Выполнялась как сварка встык, так и внахлёст при одинаковых параметрах сварки. Для всех сварных швов в качестве присадочного материала использовалась проволока типа ER 308 L. Для обоих типов швов наибольшая усталостная и ударная прочности были получены при использовании аргоновой защитной среды. Испытания на изгиб проводились до значений угла изгиба в 180°; при этом на согнутых образцах визуально не наблюдалось никаких разрывов, трещин и любых других дефектов изгиба. Свариваемый металл обладал наивысшей твёрдостью как в околошовной зоне, так и в основном материале

Dual Suppressive Effect of miR-34a on the FOXM1/eEF2-Kinase Axis Regulates Triple-Negative Breast Cancer Growth and Invasion

Purpose: Recent studies indicated that dysregulation of noncoding KNAs (ncRNA) such as miRNAs is involved in pathogenesis of various human cancers. However, the molecular mechanisms underlying miR-34a are not fully understood in triple-negative breast cancer (TNBC). Experimental Design: We performed in vitro functional assays on TNBC cell lines to investigate the role of mi R-34a in FOLM1/eEF2K signaling axis. TNBC tumor xenograft models were used for in vivo therapeutic delivery of miR-34a. Results: In this study, we investigated the role of p53-driven ncRNA miR-34a and found that miR-34a is associated with significantly longer patient survival in TNBC and inversely correlated with levels of proto-oncogenic eEF2K, which was associated with significantly shorter overall patient survival, We showed that miR-34a directly binds to the 3'-untranslated region of eEF2K and FOXM1 mRNAs and suppresses their expression, leading to inhibition of TNBC cell proliferation, motility, and invasion. Notably, restoring miR-34a expression recapitulated the effects of inhibition of eEF2K and FOXM1, the transcription factor for eEF2K and the direct target of p53, in TNBC cell lines, whereas overexpression of eEF2K and FOXM1 rescued the effects and signaling pathways mediated by miR-34a. Moreover, in vivo therapeutic delivery of miR-34a nanopartides by systemic intravenous administration delayed tumor growth of two different orthotopic TNBC tumor xenograft models by inhibiting eEF2K and FOXM1, intratumoral proliferation and angiogenesis, and inducing apoptosis. Conclusions: Overall, our findings provide new insights into the tumor suppressor role of miR-34a by dual-targeting of FOXM1/eEF2K signaling axis and suggest that miR-34a-based gene therapy may be a potential therapeutic strategy in TNBC. (C)2018 AACR.NIH/NCIUnited States Department of Health & Human ServicesNational Institutes of Health (NIH) - USANIH National Cancer Institute (NCI) [R21CA199050, P30CA016672]; noncoding RNA center; NATIONAL CANCER INSTITUTEUnited States Department of Health & Human ServicesNational Institutes of Health (NIH) - USANIH National Cancer Institute (NCI) [P30CA016672] Funding Source: NIH RePORTERThis work was supported in part by grants from the NIH/NCI (R21CA199050 and P30CA016672) and the funding from noncoding RNA center and used the Functional Proteomics RPPA Core Facility

Development and properties of polymeric nanocomposite coatings

Polymeric-based nanocomposite coatings were synthesized by reinforcing epoxy matrix with titanium nanotubes (TNTs) loaded with dodecylamine (DOC). The performance of the developed nanocomposite coatings was investigated in corrosive environments to evaluate their anti-corrosion properties. The SEM/TEM, TGA, and FTIR analysis confirm the loading of the DOC into the TNTs. The UV-Vis spectroscopic analysis confirms the self-release of the inhibitor (DOC) in response to the pH change. The electrochemical impedance spectroscopic (EIS) analysis indicates that the synthesized nanocomposite coatings demonstrate superior anticorrosion properties at pH 2 as compared to pH 5. The improved anticorrosion properties of nanocomposite coatings at pH 2 can be attributed to the more effective release of the DOC from the nanocontainers. The superior performance makes polymeric nanocomposite coatings suitable for many industrial applications.Qatar University, University of Auckland, Qatar FoundationScopu

Wear Behaviour of Crankshaft Journals Filled by Submerged Arc Welding

In this study, wear behaviour of crankshaft journals filled by a submerged arc welding with different welding wires and powders is investigated. Hardness and microstructure variations in the submerged arc welding are examined. In addition, the amount of weight loss in abrasion samples of filling dry and lubrication ambience is measured under 40 N loads. It is observed that the amount of abrasion decreased with the increase of hardness at a certain point. Thin wire structure is provided for better abrasion resistance, and abrasion decreases with lubrication.В работе исследован режим износа цапф коленчатого вала, обработанных дуговой сваркой под флюсом с различными сварочными проволоками и порошками. Изучены вариации твёрдости и микроструктуры при дуговой сварке под флюсом. Кроме того, была измерена величина потери веса в образцах, подвергнутых истиранию в сухих и смазочных средах при нагрузках в 40 Н. Наблюдалось уменьшение величины истирания с увеличением твёрдости до определённого предела. Было обеспечено использование тонкой проволоки для лучшего сопротивления истиранию, а истирание уменьшалось при смазке.В роботі досліджено режим спрацювання цапф колінчастого валу, оброблених дуговим зварюванням під флюсом з різними зварювальними дротами і порошками. Досліджено варіації твердості та мікроструктури при дуговому зварюванні під флюсом. Крім цього, було виміряно величину втрати ваги в зразках, підданих стиранню в сухих і змащувальних середовищах при навантаженнях у 40 Н. Спостерігалося зменшення величини стирання зі збільшенням твердості до певної границі. Було забезпечено використання тонкого дроту для кращого опору стиранню, а стирання зменшувалося при змащуванні

CXXC5 as an unmethylated CpG dinucleotide binding protein contributes to estrogen-mediated cellular proliferation.

Evidence suggests that the CXXC type zinc finger (ZF-CXXC) protein 5 (CXXC5) is a critical regulator/integrator of various signaling pathways that include the estrogen (E2)-estrogen receptor α (ERα). Due to its ZF-CXXC domain, CXXC5 is considered to be a member of the ZF-CXXC family, which binds to unmethylated CpG dinucleotides of DNA and through enzymatic activities for DNA methylation and/or chromatin modifications generates a chromatin state critical for gene expressions. Structural/functional features of CXXC5 remain largely unknown. CXXC5, suggested as transcription and/or epigenetic factor, participates in cellular proliferation, differentiation, and death. To explore the role of CXXC5 in E2-ERα mediated cellular events, we verified by generating a recombinant protein that CXXC5 is indeed an unmethylated CpG binder. We uncovered that CXXC5, although lacks a transcription activation/repression function, participates in E2-driven cellular proliferation by modulating the expression of distinct and mutual genes also regulated by E2. Furthermore, we found that the overexpression of CXXC5, which correlates with mRNA and protein levels of ERα, associates with poor prognosis in ER-positive breast cancer patients. Thus, CXXC5 as an unmethylated CpG binder contributes to E2-mediated gene expressions that result in the regulation of cellular proliferation and may contribute to ER-positive breast cancer progression

Comprehensive spectroscopic and photometric study of pulsating eclipsing binary star AI Hya

The pulsating eclipsing binaries are remarkable systems that provide an opportunity to probe the stellar interior and to determine the fundamental stellar parameters precisely. Especially the detached eclipsing binary systems with (a) pulsating component(s) are significant objects to understand the nature of the oscillations since the binary effects in these systems are negligible. Recent studies based on space data have shown that the pulsation mechanisms of some oscillating stars are not completely understood. Hence, comprehensive studies of a number of pulsating stars within detached eclipsing binaries are important. In this study, we present a detailed analysis of the pulsating detached eclipsing binary system AI Hya which was studied by two independent groups with different methods. We carried out a spectroscopic survey to estimate the orbital parameters via radial velocity measurements and the atmospheric parameters of each binary component using the composite and/or disentangled spectra. We found that the more luminous component of the system is a massive, cool and chemically normal star while the hotter binary component is a slightly metal-rich object. The fundamental parameters of AI Hya were determined by the analysis of binary variations and subsequently used in the evolutionary modelling. Consequently, we obtained the age of the system as 850 $\pm$ 20 Myr and found that both binary components are situated in the Delta Scuti instability strip. The frequency analysis revealed pulsation frequencies between the 5.5 - 13.0 d$^{-1}$ and we tried to estimate which binary component is the pulsating one. However, it turned out that those frequencies could originate from both binary components.Comment: Accepted for publication in MNRA

Gingival tissue human beta-defensin levels in relation to infection and inflammation.

Aim To profile gingival tissue levels of human beta-defensin (hBD)-2 and hBD-3 in relation to gingival inflammation, Th17-related cytokine concentrations, Porphyromonas gingivalis counts, and gingipain and total protease activities. Materials and Methods Gingival tissue and subgingival plaque samples were collected from 21 periodontitis patients including 48 periodontal pocket sites with marginal, mild, or moderate to severe inflammation. hBD levels were determined by immunodetection, P. gingivalis counts with real-time polymerase chain reaction, protease activities with fluorogenic substrates, and cytokine concentrations with Luminex technique. Data were statistically analysed using Kruskal-Wallis and Mann-Whitney U tests and Spearman correlation coefficients. Results Subgingival plaque counts of P. gingivalis (p = .001) and gingipain activity (p <.001), as well as interleukin (IL)-1 beta (p = .012), IL-10 (p = .024), IL-17A (p = .002), IL-17F (p = .006), and IL-23 (p = .036) concentrations were elevated in severely inflamed sites, whereas no change was observed in hBD-2 and hBD-3 levels. Negative correlations were found between protease activity and hBD-2 (p = .033) and hBD-3(p = .003) levels. Conclusions Shift in gingival inflammation from marginal to mild stage is related to elevations in subgingival plaque P. gingivalis counts and gingipain activity, but not to tissue hBD levels. Negative correlations between hBDs and total protease activity suggest the degradation of these antimicrobial peptides in progressed inflammation.Peer reviewe

Large-scale dynamics moderate impact-relevant changes to organised convective storms

Larger organised convective storms (mesoscale-convective systems) can lead to major flood events in Europe. Here we assess end-of-century changes to their characteristics in two convection-permitting climate simulations from the UK Met Office and ETH-Zürich that both use the high Representative Concentration Pathway 8.5 scenario but different approaches to represent atmospheric changes with global warming and different models. The UK Met Office projections indicate more frequent, smaller, and slower-moving storms, while ETH-Zürich projections show fewer, larger, and faster-moving storms. However, both simulations show increases to peak precipitation intensity, total precipitation volume, and temporal clustering, suggesting increasing risks from mesoscale-convective systems in the future. Importantly, the largest storms that pose increased flood risks are projected to increase in frequency and intensity. These results highlight that understanding large-scale dynamical drivers as well as the thermodynamical response of storms is essential for accurate projections of changes to storm hazards, needed for future climate adaptation