14 research outputs found
Effect of 17 alpha-Ethinylestradiol Exposure on Phycocyanin Metabolite Production and Antioxydant System of Phormidium Versicolor NCC466
No full textMicro-analysis as a Tool for the Characterization of Historical Masonry Buildings: The Decorative Elements of the Basilica Della Beata Vergine Maria Del Rosario (Polesella, Rovigo)
No full textThe Basilica of the Beata Vergine Maria del Rosario of Polesella, the subject of this study, was built in the mid-eighteenth century in the village of Polesella (in the province of Rovigo, Veneto Region, Italy). Some restoration work on the Basilica has been necessary for recent years; this has allowed sampling of interior plasters on which preliminary microanalyses have been performed to better characterize the building materials used, in support of subsequent repair work. Among the many planned restoration works, interventions on the interior walls were, in addition, also planned. For this, the interior plasters and interior painting of the church were studied through observations with SEM–EDS. The objective of this work is mainly to show how archeometric analyses can be a valuable tool to improve the knowledge and characterization of the materials used, in this case, on some decorative elements of the Basilica. In particular, regarding the frescoes, the research was also aimed at identifying the type of pigments used by the author Luigi Battisti, believed to be the author of some of the works on display
Micro-analysis as a Tool for the Characterization of Historical Masonry Buildings: The Decorative Elements of the Basilica Della Beata Vergine Maria Del Rosario (Polesella, Rovigo)
No full textThe Basilica of the Beata Vergine Maria del Rosario of Polesella, the subject of this study, was built in the mid-eighteenth century in the village of Polesella (in the
province of Rovigo, Veneto Region, Italy). Some restoration work on the Basilica has been necessary for recent years; this has allowed sampling of interior plasters
on which preliminary microanalyses have been performed to better characterize the building materials used, in support of subsequent repair work. Among the many
planned restoration works, interventions on the interior walls were, in addition, also planned. For this, the interior plasters and interior painting of the church were studied
through observations with SEM–EDS. The objective of this work is mainly to show how archeometric analyses can be a valuable tool to improve the knowledge and
characterization of the materials used, in this case, on some decorative elements of the Basilica. In particular, regarding the frescoes, the research was also aimed at
identifying the type of pigments used by the author Luigi Battisti, believed to be the author of some of the works on display
On the Frictional Sliding Contact Problem Between a Rigid Circular Conducting Punch and a Magneto-Electro Half-Plane
No full textThe frictional sliding contact problem between a homogeneous magneto-electro-elastic material (MEEM) and a perfectly conducting rigid circular punch subjected to magneto-electro-mechanical loads is considered in this paper. The problem is formulated under plane strain conditions and the resulting plane magneto-electro-elasticity equations are converted analytically using Fourier transform into three coupled singular integral equations in which the main unknowns are the normal contact stress, the electric displacement and the magnetic induction. The main contribution of this work is the derivation of an analytical closed-form solution for the normal contact stresses, electric displacement and magnetic induction distributions. The primary purpose of this investigation is to study the effect of the friction coefficient, the punch radius, the applied magneto-electro-mechanical loadings, the material composition on the contact surface and in-plane surface stresses, electric displacement and magnetic induction distributions for the case of a circular stamp profile. (C) 2014 Elsevier Ltd. All rights reserved.The first three authors are grateful for the funding provided to their laboratory by the Tunisian Ministry of Higher Education and Scientific Research. The third author is grateful for the support of Texas A;M University at Qatar. The last author gratefully acknowledges the financial support from the Scientific and Technological Research Council of Turkey through Grant MAG-107M053. This author is also grateful for the support provided by the Fulbright Visiting Scholar Program
Static and Fatigue Bond Assessment of CFRP-Concrete Joints Extracted from 60-Year-Old Bridge Girders after 7 Years of service
No full textThis paper investigates the bond behavior under static and fatigue loading of a carbon fiber reinforced polymer (CFRP) external strengthening system applied to 60-year-old bridge girders after exposure to 7 years real service conditions. The experimental results on CFRP-concrete joints were compared with the results of control tests carried out on new samples prepared in the laboratory. The results indicate that the bond strength of the CFRP-concrete joints extracted from the bridge was decreased by 38.8 % in comparison with the reference samples. In addition, it was revealed that the failure mode changed from cohesive failure in the concrete to failure of the adhesive/concrete interface and cohesive failure of the adhesive layer after exposure to service conditions. On the other hand, fatigue test results showed that the CFRP-concrete joints extracted from the bridge showed a significant degradation in fatigue life and interfacial bond stiffness compared to the control samples.The presentation of the authors' names and (or) special characters in the title of the pdf file of the accepted manuscript may differ slightly from what is displayed on the item page. The information in the pdf file of the accepted manuscript reflects the original submission by the author
The Contact Problem of a Rigid Stamp With Friction on a Functionally Graded Magneto-Electro Half-Plane
No full textWe consider in this study the frictional sliding contact problem between a functionally graded magneto-electro-elastic material and a perfectly conducting rigid punch subjected to magneto-electro-mechanical loads. The problem is formulated under plane strain conditions. Using Fourier transform, the resulting plane magneto-electro-elasticity equations are converted analytically into three coupled singular integral equations in which the unknowns are the normal contact stress, the electric displacement and the magnetic induction. These integral equations are then solved numerically to obtain the distributions of the normal contact stress, electric displacement and magnetic induction at the surface of the graded medium. The main objective of this paper is to study the effect of the non-homogeneity parameter, the friction coefficient and the elastic, electric and magnetic coefficients on the surface contact pressure, electric displacement and magnetic induction distributions for the case of flat and circular punch profiles.The second author is grateful for the support provided by Texas A;M University at Qatar
Exploring the oxygen and carbon isotopic composition of the Mediterranean red coral (Corallium rubrum) for seawater temperature reconstruction
No full text© The Author(s), 2016. This is the author's version of the work and is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Marine Chemistry 186 (2016): 11-23, doi:10.1016/j.marchem.2016.07.001.Here we provide first evidence that the stable oxygen and carbon isotopic composition
(δ18O, δ13C) of the high-magnesium calcite skeleton red coral Corallium rubrum can be used
as a reliable seawater temperature proxy. This is based upon the analyses of living colonies of
C. rubrum from different depths and localities in the Western Mediterranean Sea. The
assessment of the growth rates has been established through the analysis of growth band
patterns. The δ18O and δ13C compositions show large variability with a significant difference
between the branches and the bases of the colonies. In both coral portions, the δ18O and δ13C
values are highly correlated and show well-defined linear trends. Following the “lines
technique” approach developed by Smith et al. (2000) for scleractinian aragonitic deep-water
corals, our data have been combined with published values for the deep-sea gorgonian corals
Isididae and Coralliidae from Kimball et al. (2014) and Hill et al. (2011) resulting in the
following δ18O temperature equation: T (°C) = 38 -5.05 ± 0.24 x (δ18Ointercept) + 14.26 ± 0.43
(R² = 0.962, p value < 0.0001)
The error associated with this equation is ± 0.5 °C at the mean temperature of the data
set, ± 0.7 °C for corals living in 2 °C water and ± 1 °C for coral living in warmer water (17
°C).
The highly significant δ18Ointercept vs. temperature relationship combined with the
“lines technique” method can be reliably applied to the calcitic skeleton to obtain calcification
temperature estimates in the past, although this approach requires the knowledge of the past
δ18O and δ13C composition of seawater and it is labor and time intensive.We are grateful for the financial support
of the MISTRALS-PaleoMeX and ENVIMED projects.2018-07-0
Protective effect of Cinnamomum zeylanicum L. bark essential oil, on hepatic and renal toxicity induced by CCl4 in rats
No full textThe inner bark of cinnamon (Cinnamomum zeylanicum L.) is widely used as a spice. Cinnamomum plants are also a valuable sources of essential oil used for medicinal purposes. The present study aimed to investigate: the composition, the in vitro antioxidant activity of C. zeylanicum bark essential oil (CzEO) and its protective effects in vivo on CCl4-induced hepatic and renal toxicity in rats.
Groups of animals were pretreated for seven days with different concentrations of CzEO or controls and on day 7 a single dose of CCl4 was used to induce oxidative stress in rats. Twenty-four hours after CCl4 administration, the animals were sampled. In the controls, CCl4 induced an increase of serum biochemical parameters and triggered oxidative stress in both liver and kidneys. CzEO (100 mg/kg) caused significant reductions in CCl4-elevated levels of ALT, AST, ALP, LDH, ÎłGT,total cholesterol, triglycerides, LDL urea and creatinine and increased the level of HDL compared to the CCl4 group. Moreover, pre-treatment with the CzEO at doses of 70 and 100 mg/kg BW to the rats treated with CCl4 produced significant reductions in TBARS and PCO levels in liver and kidney tissues as compared to CCl4 group. The formation of pathological hepatic and kidney lesions induced by the administration of CCl4 was strongly prevented by CzEO at a dose of 100 mg/kg BW.
Overall, this study suggests that administration of CzEO displayed high potential to quench free radicals and alleviate CCl4-induced hepatorenal toxicity in rats.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author
Extraction yield optimization of Oleaster (Olea europaea var. sylvestris) fruits using response surface methodology, LC/MS profiling and evaluation of its effects on antioxidant activity and autophagy in HFF cells
No full textOleaster (Olea europaea var. sylvestris) is a wild olive tree distributed in the Mediterranean area. It is known to possess several biological activities due to their richness in polyphenols. However, enhanced autophagic activity in human cells by using this plant has not been studied before. The objective of the present study was to determine the phytochemical composition of the fruits paste from Tunisian Oleaster, and evaluate its antioxidant activity using the DPPH• and ABTS•+ methods as well as the evaluation of its effect on autophagy activity. The extraction conditions were optimized using response surface methodology (RSM) leading to the best phenolic extract yield. It was noted that ethyl acetate extract presented the highest amount of total phenols and the best solvent for extraction of phenolic compounds. After optimization, the ethyl acetate extract was fractionated into 15 fractions by silica gel column chromatography. The most phenolic components in the fifth and sixth fractions (F5 and F6) were identified using UPLC-ESI(-)-HRMS analysis. Accordingly, F6 was the richer fraction in polyphenols. In vitro antioxidant activity evaluation showed that F6 exhibited a strong ability to scavenge DPPH and ABTS radicals. Furthermore, this fraction was also the most effective to induce autophagic activity in Human foreskin fibroblasts (HFF) cells. These results could be presumably due to the presence of oleuropein aglycon in this fraction which is absent in fraction F5. Oleaster fruits paste would be used as a natural source of bioactive compounds useful in various pharmaceutical drugs. © 2021, The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature
Cross-layer operation aided wireless networks
No full textIn this thesis, we propose several cross-layer operation aided schemes conceived for wireless networks. Cross layer design may overcome the disadvantages of the network's layered architecture, where layering is most typically represented by the Transport Control Protocol (TCP) / Internet Protocol (IP) suite.We invoke Fountain codes for protecting file transfer at the application layer, since they are suitable for erasure channels. They are also often referred to as rateless codes. When implementing Fountain code aided file transfer, the file will be firstly partitioned into a number of blocks, each of which contains K packets. Fountain codes randomly select several packets from a block and then combine them using exclusive- OR additions for generating an encoded packet. The encoding continues until all blocks are successfully received. Considering an 802.11 Wireless Local Area Network (WLAN) scenario, the packet size has to be appropriately chosen, since there exists a trade-off between the packet size and the transmission efficiency, which is defined as the number of primary information bits to the total number of all transmitted bits including headers, control packets and retransmitted replicas. In order to find the optimum packet size, the transmission efficiency is formulated as a function of the Packet Loss Ratio (PLR) at the application layer and of the total load imposed by a single packet. The PLR at the application layer is related both to the packet size, as well as to the 802.11 MAC retransmission mechanism and to the modulation scheme adopted by the physical layer. Apart from its source data, the total load imposed by an information packet also contains the control packets of the 802.11 Media Access Control (MAC) protocol such as the Request To Send (RTS) / Clear To Send (CTS) messages, the retransmitted replicas and the Acknowledgement (ACK) messages. According to these relations, the transmission efficiency may finally be expressed as a function of packet size. Based on the numerical analysis of this function, the optimum packet size may be determined. Our simulation results confirmed that indeed the highest transmission efficiency may be achieved, when using the optimum packet size.Since turbo codes are capable of achieving near capacity performance, they may be successfully combined with Hybrid Automatic Repeat reQuest (HARQ) schemes. In this thesis, the classic Twin Component Turbo Codes (TCTCs) are extended to Multiple Component Turbo Codes (MCTCs). In order to apply classic two-dimensional Extrinsic Information Transfer (EXIT) charts for analyzing them, we divided an N-component MCTC into two logical parts. This partitioning was necessary, because otherwise an N-component scheme would require an N-dimensional EXIT chart. One of the parts is constituted by an individual Bahl, Cocke, Jelinek and Raviv (BCJR) decoder, while the other so-called composite decoder consists of the remaining (N-1) components. The EXIT charts visualized the extrinsic information exchange between these two logical parts of MCTCs. Aided by this partitioning technique, we may find the so-called 'open tunnel SNR threshold' for MCTCs, which is defined as the minimum SNR for which the EXIT chart at the specific coding rate used has an open tunnel. It may be used as a metric to compare the achievable performance to the Discrete-input Continuous-output Memoryless Channel's (DCMC) capacity. Our simulation results showed that the achievable performance of MCTCs is closer to the DCMC capacity than that of non-systematic TCTCs, but a bit further than that of systematic TCTCs, if generator polynomials having an arbitrary memory length - and hence complexity - are considered. However, for the lowest-memory octally represented polynomial (2; 3)o, which implies having the lowest possible complexity, MCTCs outperform non-systematic and systematic TCTCs. Furthermore, MCTC aided HARQ schemes using the polynomial of (2; 3)o exhibit significantly better PLRs and throughput performances than systematic as well as non-systematic TCTC aided HARQ schemes using the same polynomial. If systematic TCTC aided HARQ schemes relying on the polynomial of (17; 15)o are used as benchmarkers, MCTC aided HARQ schemes may significantly reduce the complexity, without a substantial degradation of the PLR and throughput.When combining turbo codes with HARQ, the associated complexity becomes a critical issue, since iterative decoding is immediately activated after each transmission. In order to reduce the associated complexity, an Early Stopping (ES) strategy was proposed in this thesis to substitute the fixed number of BCJR operations invoked for each iterative decoding. By observing the EXIT charts of turbo codes, we note that the extrinsic information increases along the decoding trajectory of an open or closed tunnel. The ES aided MCTC HARQ scheme curtails iterative decoding, when the Mutual Information (MI) increase becomes less than a given threshold. This threshold was determined by an off-line training in order to achieve a trade-off between the throughput and complexity. Our simulation results verified that the complexity of MCTC aided HARQ schemes may be reduced by as much as 80%, compared to that of systematic TCTC aided HARQ schemes using a fixed number of 10 BCJR operations.Moreover, the complexity of turbo coded HARQ schemes may be further reduced by our Look-Up Table (LUT) based Deferred Iteration (DI) method. The DI method delays the iterative decoding until the receiver estimates that it has received sufficient information for successful decoding, which may be represented by the emergence of an open tunnel in the EXIT chart corresponding to all received replicas. Therefore, the specific MI that a 'just' open tunnel appears when combining all previous (i-1) MIs will be the threshold that has to be satisfied by the ith reception. More specifically, if the MI received during the ith reception is higher than this threshold, the EXIT tunnel is deemed to be open and hence the iterative decoding is triggered. Otherwise, iterative decoding will be disabled when the tunnel is deemed to be closed. This reduces the complexity. The LUT stores all possible MI thresholds for N-component MCTCs, which results in a large storage requirement, if N becomes high. Hence, an efficient LUT design was also proposed in this thesis. Our simulation results demonstrated the achievable complexity reduction may be as high as 50%, compared to the schemes operating without the DI method
