Corrosion Protection Enhancement on Aluminum Alloy And Magnesium Alloy by Mo-CeO2 conversion coating

AbstractIn this paper, Mo-CeO2 conversion coating was developed to protect Aluminum 2024 alloy and Magnesium AZ31 alloy against corrosion.The cerium oxide was incorporated in Molybdenum conversion coating which is considered as a promising alternative to replace chromate compounds. The corrosion efficacy was improving and has been characterized by polarization curves and EIS measurements.The structural and the microstructural Mo-CeO2 conversion coating was characterized by AFM, SEM and XRD and the mechanical proprieties was determined by nano indentation. The presence of molybdenum and oxide of cerium was confirmed with good physical and mechanical proprieties.The presence of CeO2 in the conversion coating had a beneficial effect on the corrosion resistance of the both materials

Synthesis and biological activities of 5H-furo [3,2-g] [1] benzopyran-5-one derivatives

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Relationship between biomarkers of muscle damage and redox status in response to a weightlifting training session: effect of time-of-day

The aims of the present study were to: (1) investigate the effect of a weightlifting training session and time-of-day (TOD) upon biological parameters (i.e., oral temperature, hematological, C-reactive protein (CRP), and oxidative stress) and (2) assess their possible link with muscle damage responses. Nine weightlifters (21 ± 0.5 years) performed, in a randomized order, three Olympic-Weightlifting sessions (i.e., at 08:00, 14:00, and 18:00). Blood samples were collected at rest, 3 min and 48 h after each training session. Between pre- and post-training session, ANOVA showed significant increases in oxidative stress markers at the three TODs (p < 0.01) and significant increases for creatine kinase (CK) and lactate dehydrogenase (LDH) only at 08:00 and 18:00 (p < 0.05). At rest, the results showed a significant diurnal variation for the majority of the selected parameters except for malondialdehyde (MDA), total bilirubin, and CRP with higher values observed at 18:00 (p < 0.05). After the training session, given the higher rate of increase during the morning session, these diurnal variations persisted for temperature and WBC (p < 0.01) and were suppressed for CK, LDH, uric acid (UA), catalase, and glutathione peroxidase. The main significant correlations (p < 0.001) were observed between: (1) CK and MDA (r = 0.6) and CK and UA (r = 0.66 and r = 0.82) during the morning and evening training sessions; (2) CK and CRP only during the morning session (r = 0.5); and (3) CRP and WBC during the three training sessions (r = 0.8). In conclusion, the present findings: (1) confirm that the muscle damage responses could be induced by a high level of oxidative stress and (2) suggest to avoid scheduling training sessions in the morning given the higher muscle damage, inflammatory, and oxidative responses at this TOD

Morning melatonin ingestion and diurnal variation of short-term maximal performances in soccer players

Aim Very few studies have investigated the temporal specificity of melatonin (MEL) ingestion upon short-term maximal athletic performances. The aim of the present study was to explore the effect of morning MEL ingestion on cognitive and physical performances measured in the afternoon. Methods Twelve soccer players from a Tunisian squad (17.9 ± 1.3 years, 1.74 ± 0.06 m and 62.0 ± 8.8 kg) participated in the present study. They performed two testing sessions at 08:00 h, 12:00 h and 16:00 h after either MEL (5mg) or placebo (PLA) ingestion, in a randomized order. During each period, the participants performed the following cognitive and physical tests: reaction time and vigilance tests, medicine-ball throw (MBT), five jumps, handgrip strength (HG), and agility tests. Results cognitive and physical performances were significantly higher at 16:00 h compared to 08:00 h during the two conditions (p < 0.05). Moreover, performances of MBT and HG were lower in the morning with MEL in comparison to PLA (p < 0.05). However, MEL ingestion did not affect physical and cognitive performances measured at 12:00 h and 16:00 h. Conclusion morning MEL ingestion has no unfavourable effect on afternoon physical and cognitive performances in soccer players

POTENTIAL ROLE OF MILK THISTLE SEED AND ITS OIL EXTRACTS AGAINST HEART AND BRAIN INJURIES INDUCED BY γ-RADIATION EXPOSURE

Objective: This study aimed to investigate the protective effect of Silybum marianum (S. marianum) seeds extract its oil fraction against damage effect of γ-radiation in female albino rats.Methods: Ultrasonic-assisted extraction was used for the extraction of S. marianum seeds. Lipid patterns of S. marianum seeds oil were elucidated using gas chromatography-mass spectrometry (GC-MS). S. marianum seeds extract was analyzed using high-performance liquid chromatography (HPLC). Malondialdehyde (MDA), reduced glutathione (GSH) and metallothionein (MT) were estimated in heart and brain tissues of the examined rats. Lactate dehydrogenase (LDH) and creatine kinase-MB (CKMB) were measured in the serum of the examined rats, and the brain biomarkers; dopamine and serotonin were also measured.Results: The oil was found to be rich in linoleic acid (58.20%) and arachidic acid (23.38%). S. marianum seeds extract revealed the presence of taxifolin and six main active constituents of silymarin, including silydianin, silychristin, silybin A, silybin B, isosilybin A and isosilybin B. Treatment of γ-radiation damage effect using S. marianum seeds extract and its oil fraction led to a significant reduction of MDA levels in heart (139.6 and 165.5 nmol/g, respectively) and brain (158.5 and 135.2 nmol/g, respectively) tissues, however, significant increase of GSH levels in heart (316.4 and 293 mg/g, respectively) and brain (210.4 and 227 mg/g, respectively) tissues was observed, also a significant increase of dopamine levels (85.27 and 65.74 ng/g, respectively) and MT levels of heart tissues (108.5 and 70.52 mg/g, respectively) was observed.Conclusion: S. marianum seeds extract and its oil fraction showed a protective effect against γ-radiation-induced damage in heart and brain.Â

Modelling, control design, and analysis of the inner control's loops intended for single‐phase voltage‐controlled inverter‐based microgrid

In voltage-controlled voltage source inverters (VSIs)-based microgrids (MGs), the inner control is of prime interest task for guaranteeing safe and stable operation. In this paper, an in-depth investigation of the modelling, control design, and analysis of the voltage and current inner control loops intended for single-phase voltage-controlled VSIs is established. The main objective of this work is to provide a comprehensive study of the mathematical modelling, control design, and performance evaluation of the inner control's loops considering different proportional-integral (PI) controller types with and without compensation, and to determine the optimal scheme that can offer better performance in terms of implementation simplicity, robustness, and transient and steady-state responses. Thus, the mathematical closed-loop models of designed outer voltage and inner current control schemes based on PI, P, and feedforward controllers with and without compensation are, first, derived. Following this, a systematic and effective control design for tuning the different PI controllers’ parameters is proposed. Furthermore, an analysis revealing the performance of the designed voltage and current control schemes is provided. This analysis enables us to choose a P controller and PI feedforward controller for the current control loop and the voltage control loop, respectively. The chosen P and PI controllers should be simple; meanwhile, they should offer a wide bandwidth. A simulation study is carried out in MATLAB/Simulink software to assess the performance of the adopted inner control scheme for both linear and non-linear loads. In addition, an experimental setup, based on a TMS320F2837xD μC, of a single-phase VSI supplying linear and non-linear loads is built to verify the effectiveness and the robustness of the adopted inner controller. The results demonstrated: (1) the necessity of introducing the compensation term, which is responsible for offering control improvement against voltage perturbation, (2) the high tracking performance of the chosen controller in terms of dynamic and steady-state responses as well as its simplicity of implementation

Metabolic aspects of surgical subcutaneous fat removal: An umbrella review and implications for future research

Although obesity is a preventable disease, maintaining a normal body weight can be very challenging and difficult, which has led to a significant increase in the demand for surgical subcutaneous fat removal (SSFR) to improve physical appearance. The need for SSFR is further exacerbated because of the global rise in the number of bariatric surgeries, which is currently the single most durable intervention for mitigating obesity. Fat tissue is now recognized as a vital endocrine organ that produces several bioactive proteins. Thus, SSFR-mediated weight (fat) loss can potentially have significant metabolic effects; however, currently, there is no consensus on this issue. This review focuses on the metabolic sequelae after SSFR interventions for dealing with cosmetic body appearance. Data was extracted from existing systematic reviews and the diversity of possible metabolic changes after SSFR are reported along with gaps in the knowledge and future directions for research and practice. We conclude that there is a potential for metabolic sequelae after SSFR interventions and their clinical implications for the safety of the procedures as well as for our understanding of subcutaneous adipose tissue biology and insulin resistance are discussed