Search Results (19)

The development of MIG (metal inert gas) welding for five-series aluminum alloys primarily involves the improvement and optimization of welding processes. Building upon research findings regarding the enhancement of aluminum alloy properties through the use of scandium (Sc) and erbium (Er), our study incorporates Sc and Er into the welding wire to examine their impact on welding quality. The results show that the introduction of Er and Sc results in grain refinement from 47 µm to 29 µm and 31 µm, respectively. Grain refinement is mainly attributed to the heterogeneous nucleation of submicron-sized, coherent Al₃Er and Al₃Sc phases with L12 structure. The ultimate tensile strength (UTS), fracture elongation EI [%], and microhardness of joints welded with Er-containing and Sc-containing filler wires exhibit significant enhancements due to the refinement strengthening and dispersion strengthening. Joints welded with the filler wires containing Er and Sc display reduced corrosion current density and higher corrosion potential. The enhanced corrosion resistance comes from the formation of a denser oxide film and the equilibrium in the potential difference between the precipitated phases (Al₃Er and Al₃Sc) and the matrix. Filler wires containing Er and Sc have almost similar effects on improvements of the MIG welding joints. Full article

This work presents a comparative study of five rare earth compounds—Erbium nitrate pentahydrate lll (Er), Neodymium nitrate pentahydrate (Nd), Samarium III Nitrate Hexahydrate (Sm), Yterbium III Chloride Hexahydrate (Yb) and Praseodymium nitrate hexahydrate lll (Pr)—protecting API 5L X70 steel from corrosion in saline medium that uses electrochemical impedance spectroscopy (EIS) and polarization curves (CPs) at different concentrations and in static mode. The results show that Erbium is the best corrosion inhibitor, containing 50 ppm and reaching an inhibition efficiency of about 89%, and similar result was shown by Sm with an IE~87.9%, while the other rare earths (Nd, Yb and Pr) showed a decrease in corrosion protection at the same concentration, since they were below an IE~80%. On the other hand, with the Langmuir model it was possible to describe that the adsorption process of the three rare earths follows a combined physisorption–chemisorption process to protect the metal’s surface. The observed adsorption free energy, ΔG°ads, reaches −38.7 kJ/mol for Er, −34.4 kJ/mol for Nd, and −33.6 kJ/mol for Pr; whereas Sm and Yb have adsorption free energies of −33.9 and −35.0 kJ/mol, respectively. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) further confirmed the formation of a protective film. Their characterization using density functional theory showed the transference of charge from the iron cluster towards the rare earth metal compounds. The adsorption process produced a slightly polarized region of interaction with the metal surface. Also, it was found that the adsorption of the rare earths affected the magnetic properties of the surface of the iron cluster. Quantum chemical descriptors, such as Pearson’s HSAB (Hard and Soft Acids and Bases) descriptors, were useful in predicting the behavior of the flow of electrons between the metal surface and the interacting rare earth ions. Full article

Edible Insects (EIs) are an alternative source of bioactive compounds such as proteins or fatty acids and micronutrients as vitamins or minerals, thus showing potential to replace traditional foodstuffs in an economical and environmentally friendly way. Nonetheless, EIs can accumulate hazardous chemicals such as mycotoxins and heavy metals. The aim of the present study is to determine mycotoxins and heavy metal content in raw insect samples and those resulting products obtained after supercritical fluid extraction (SFE). Insect samples included Acheta domesticus (cricket) meal, Tenebrio molitor (mealworm) meal, Alphitobius diaperinus (buffalo worm), and Locusta migratoria (locust). For this purpose, a QuEChERS method followed by LC-MS/MS analysis was optimized with good results for the analysis of mycotoxins, principally Aflatoxins (AFs), Ochratoxin A (OTA), and Enniatins (ENNs). In contrast, heavy metals (As, Cd, Hg, Pb) were determined by Inductively Coupled Plasma Mass Spectrometry (ICP-MS). The results obtained revealed that Locust was positive for AFG2 at a level of 115.5 μg/kg, and mealworm was only contaminated with OTA at 58.1 μg/kg. Emerging mycotoxins (ENNA, ENNA1, ENNB, and ENNB1) were detected at lower levels < 2.2 µg/Kg. Concerning heavy metals, limits exceeding regulation were detected for Cd in the insect species studied, with levels up to 219 μg/kg, and for Pb in crickets (100.3 μg/kg). Finally, the analysis of the post-extraction solids after SFE processing revealed that heavy metals remained in the resulting SFE cakes, while mycotoxins were detected at negligible levels (up to 1.3 µg/Kg). Full article

This paper examines personal names derived from traditional religious beliefs and practices among the Erei people in Biase Local Government Area of Cross River State in South-South, Nigeria while utilising insights from the multidisciplinary inferences of socio-onomastic theory to account for the cultural, social and situational contexts that create the religious content of the names. Data were obtained by means of participant observation and semi-structured interviews during six months of fieldwork involving 40 participants who were the name-givers, name-bearers and name-users. Our findings highlight the socio-onomastic tradition of Erei people in which personal names are bestowed through a conscious application of symbolic linguistic resources to express and perform ideologies and identities that are rooted in the traditional religion’s foundations and sociocultural practices that represent Erei people’s indigenous beliefs system and spiritual worldview. Focused on the ideals of African traditional religion, religious identities are constructed through the use of personal names related to idol worship, the mysteries of death, reincarnation and commemoration, cultural festivals and performances, symbolic objects, familial rankings and other aspects derived from their environment that also bear traditional religious significance. And because this set of personal names is now predominant among the ageing population and is losing contemporaneity due to an increasing subpopulation with a new (Christian) beliefs system, this study serves to preserve a transiting and endangered Erei socio-onomastic practice that represents the people’s traditional cosmology. Full article

The Rolling Hilly Region of Northeast China (RHRNEC) is a critical grain production area in China, and soil erosion is a major problem in this region. To determine spatial and temporal changes in rainfall erosivity (RE) in the RHRNEC and generate information useful for soil and water conservation, agricultural management, and ecological protection efforts, a RE index consisting of nine erosivity indices based on normal and extreme precipitation was established. The normal RE index (NREI) comprised annual RE (ARE), wet season RE (WRE), dry season RE (DRE), typical wet-month RE (TWRE), and typical dry-month RE (TDRE), and the extreme RE index set (EREI) comprised maximum one-day RE (RE × 1 day), maximum five consecutive days RE (RE × 5 day), storm RE (RE50), and maximum continuous RE (CRE). ARE, WRE, and TWRE decreased at relative rates of 2.5%, 2.9%, and 4.1%, respectively. By comparison, DRE increased at a non-significant relative rate of 6.3%, and all extreme RE indices decreased at a non-significant rate relative to 1981–2015 mean values. The future trends for all RE indices were predicted to be opposite to historical trends. The future trends and historical trends of all indices exhibited opposite patterns. RE gradually increased from north to south, and WRE, DRE, and all extreme RE indices were significantly negatively correlated with longitude, latitude, and altitude (p < 0.05). ARE, WRE, and TWRE showed increasing trends in the north and south and decreasing trends in the center. The findings are useful for soil and water conservation, especially for agricultural management and ecological protection. Full article

Generally, our ecosystem is continuously contaminated as a result of anthropogenic activities that form the basis of our comfort in our routine life. Thus, most scientists are engaged in the development of new technologies that can be used in environmental remediation. Herein, highly calcined binary metal oxide (Er₂O₃@NiO) semiconductor nanocomposite (NC) was synthesized using a classical wet chemical process with the intention to both detect and degrade the toxic chemicals in an aqueous medium using a novel electrochemical current–potential (I–V) approach for the first time. Optical, morphological, and structural properties of the newly synthesized semiconductor NC were also studied in detail using FT-IR, UV/Vis., FESEM-EDS, XPS, BET, EIS, and XRD techniques. Then, a modified glassy carbon electrode (GCE) based on the newly synthesized semiconductor nanocomposite (Er₂O₃@NiO-NC/Nafion/GCE) as a selective electrochemical sensor was fabricated with the help of 5% ethanolic-Nafion as the conducting polymer binder in order to both detect and electro-hydrolyze toxic chemicals in an aqueous medium. Comparative study showed that this newly developed Er₂O₃@NiO-NC/Nafion/GCE was found to be very selective against m-tolyl hydrazine (m-Tolyl HDZN) and to have good affinity in the presence of other interfering toxic chemicals. Analytical parameters were also studied in this approach to optimize the newly designed Er₂O₃@NiO-NC/Nafion/GCE as an efficient and selective m-Tolyl HDZN sensor. Its limit of detection (LOD) at an SNR of 3 was calculated as 0.066 pM over the linear dynamic range (LDR) of our target analyte concentration (0.1 pM–0.1 mM). The limit of quantification (LOQ) and sensitivity were also calculated as 0.22 pM and 14.50 µAµM⁻¹cm⁻², respectively. m-Tolyl HDZN is among the toxic chemicals in our ecosystem that have lethal effects in living beings. Therefore, this newly designed electrochemical sensor based on semiconductor nanostructure material offers, for the first time, a cost-effective technique, in addition to long-term stability, that can be used as an alternative for efficiently probing other toxic chemicals in real samples. Full article

Through kidney transplantation, ischemia/reperfusion is known to induce tissular injury due to cell energy shortage, oxidative stress, and endoplasmic reticulum (ER) stress. ER stress stems from an accumulation of unfolded or misfolded proteins in the lumen of ER, resulting in the unfolded protein response (UPR). Adaptive UPR pathways can either restore protein homeostasis or can turn into a stress pathway leading to apoptosis. We have demonstrated that N1-guanyl-1,7-diamineoheptane (GC7), a specific inhibitor of eukaryotic Initiation Factor 5A (eIF5A) hypusination, confers an ischemic protection of kidney cells by tuning their metabolism and decreasing oxidative stress, but its role on ER stress was unknown. To explore this, we used kidney cells pretreated with GC7 and submitted to either warm or cold anoxia. GC7 pretreatment promoted cell survival in an anoxic environment concomitantly to an increase in xbp1 splicing and BiP level while eiF2α phosphorylation and ATF6 nuclear level decreased. These demonstrated a specific modulation of UPR pathways. Interestingly, the pharmacological inhibition of xbp1 splicing reversed the protective effect of GC7 against anoxia. Our results demonstrated that eIF5A hypusination inhibition modulates distinctive UPR pathways, a crucial mechanism for the protection against anoxia/reoxygenation. Full article

The present study examined if Emotional Intelligence (EI), resilience, and self-esteem predicted life satisfaction in university students. We computed correlations between the study variables, then, we compared the differences between men and women. Finally, a simultaneous multiple regression was performed. The sample was composed of 2574 university students (715 were men and 1859 were women), whose age ranged from 18 to 30 years with a mean (M) of 20.83 and a standard deviation (SD) of 2.45. The instruments used were the Wong and Law Emotional Intelligence Scale (WLEIS), the Wagnild and Young Resilience Scale (ER-25), the Rosenberg Self-Esteem Scale (RSES), and the Diener Satisfaction with Life Scale (SWLS). The results indicated that EI, self-esteem, and resilience correlated significantly and directly with satisfaction with life. Regarding sex differences, it was found that men had greater resilience, appraisal and recognition of emotion in others, and self-regulation of emotion. Women had greater appraisal and expression of emotion in self and self-esteem. The results showed that self-esteem, self-regulation of emotion, the use of emotion to facilitate performance, and acceptance of self and life as resilience factors predicted satisfaction with life. accounting for 48% of the variance. The variable that best predicted satisfaction with life was self-esteem. Full article

The article is another in a series of follow-up articles on the new spectroscopic method Energy Resolved–Electrochemical Impedance Spectroscopy (ER-EIS) and presents a continuation of the effort to explain the method for electronic structure elucidation and its possibilities in the study of organic polymeric semiconductors. In addition to the detailed information on the electronic structure of the investigated organic semiconductor, the paper deals with three of the hitherto not solved aspects of the method, (1) the pores structure, which has been embedded in the evaluation framework of the ER-EIS method and shown, how the basic quantities of the pores structure, the volume density of the pores’ density coefficient β = (0.038 ± 0.002) nm⁻¹ and the Brunauer-Emmet-Teller surface areas SABET SA == 34.5 m²g⁻¹ may be found by the method, here for the archetypal poly(3-hexylthiophene-2,5-diyl) (P3HT) films. It is next shown, why the pore’s existence needs not to endanger the spectroscopic results of the ER-EIS method, and a proper way of the ER-EIS data evaluation is presented to avoid it. It is highlighted (2), how may the measurements of the pore structure contribute to the determination of the, for the method ER-EIS important, real rate constant of the overall Marcus’ D-A charge-transfer process for the poreless material and found its value k_ctD-A = (2.2 ± 0.6) × 10⁻²⁵ cm⁴ s⁻¹ for P3HT films examined. It is also independently attempted (3) to evaluate the range of k_ctD-A, based on the knowledge of the individual reaction rates in a chain of reactions, forming the whole D-A process, where the slowest one (organic semiconductor hopping transport) determines the tentative total result k_ctD-A ≅ 10⁻²⁵ cm⁴ s⁻¹. The effect of injection of high current densities by redox interface reactions in the bulk of OS with built-in pores structure may be very interesting for the design of new devices of organic electronics. Full article

7N01-T4 aluminum alloy plates were welded by the metal inert gas (MIG) welding method, with ER5087 and ER5356 welding wires, respectively. The electrochemical corrosion behavior of the weld zones in the two kinds of welded joints using 3.5 wt.% and 5 wt.% NaCl solutions were investigated by polarization curve, electrochemical impedance spectroscopy (EIS), scanning electron microscope (SEM), and laser confocal scanning microscope (LCSM). The results indicated the better corrosion resistance of the weld zone in the ER5356 welded joint than that in the ER5087 welded joint, which was related to the different contents of Mn and Zn elements and the distribution of precipitates for the weld zones in the two kinds of welded joints. Based on the LSCM of the weld zones, the maximum depth (d_max) of corrosion pits for the weld zone in the ER5356 welded joint was lower than that in the ER5087 welded joint when immersed in the same NaCl concentrations. The d_max of the corrosion pit of the weld zone in the ER5356 welded joint using the 5 wt.% NaCl solution was 78.5 ± 0.96 μm, which was much bigger than that using the 3.5 wt.% NaCl solution. For the weld zone in the ER5087 welded joint with 5 wt.% NaCl solution, more Cl^- was adsorbed onto the active surface of weld zones, which accelerated the corrosion, resulting in the corrosion mechanism from pitting to intergranular corrosion. Full article

Electronic devices based on polymer thin films have experienced a tremendous increase in their efficiency in the last two decades. One of the critical factors that affects the efficiency of polymer solar cells or light emitting devices is the presence of structural defects that controls non-radiative recombination. The purpose of this report is to demonstrate a non-trivial thickness dependence of optoelectronic properties and structure (dis)order in thin conductive poly(9,9-dioctyfluorene-alt-benzothiadiazole), F8BT, polymer films. The UV-Vis absorption spectra exhibited blue shift and peak broadening; significant changes in 0–0 and 0–1 radiative transition intensity was found in photoluminescence emission spectra. The density of state (DOS) was directly mapped by energy resolved-electrochemical impedance spectroscopy (ER-EIS). Satellite states 0.5 eV below the lowest unoccupied molecular orbital (LUMO) band were revealed for the thinner polymer films. Moreover, the decreasing of the deep states density in the band gap manifested an increment in the material structural ordering with increasing thickness. Changes in the ratio between crystalline phases with face-on and edge-on orientation of F8BT chains were identified in the films by grazing-incidence wide angle X-ray scattering technique. A thickness threshold in all investigated aspects of the films at a thickness of about 100 nm was observed that can be attributed to the development of J-H aggregation in the film structure and mutual interplay between these two modes. Although a specific structure–property relationship thickness threshold value may be expected for thin films prepared from various polymers, solvents and under different process conditions, the value of about 100 nm can be generally considered as the characteristic length scale of this phenomenon. Full article

A variety of techniques are available for monitoring metal corrosion in electrolytes. However, only some of them can be applied in the atmosphere, in which case a thin discontinuous electrolyte film forms on a surface. In this review, we describe, evaluate and compare both traditional and state-of-the-art real-time corrosion monitoring techniques to identify those suitable for atmospheric conditions. For atmospheric corrosion monitoring (ACM), electrochemical impedance spectroscopy (EIS), electrochemical noise (EN), electrical resistance (ER) probes, quartz crystal microbalance (QCM), radio-frequency identification sensors (RFID), fibre optic corrosion sensors (FOCS) and respirometry, the underlying principles, characteristics and application examples are described, and their advantages and drawbacks outlined. Finally, the techniques are compared in terms of their sensitivity, ease of setup, data processing, ability to identify underlying corrosion mechanisms and applicability in different fields of atmospheric corrosion protection and research. Full article

Improvements in the lubrication of metal–metal joint prostheses are of great clinical interest in order to minimize the particles released during wear–corrosion processes. In this work, electrochemically reduced graphene oxide (ErGO) on CoCr was functionalized with hyaluronic acid (ErGOHA). Functionalization was carried out by soaking for 24 h in phosphate buffer saline (PBS) solution containing 3 g/L hyaluronic acid (HA). The corrosion performance of CoCrErGO and CoCrErGOHA surfaces was studied by electrochemical impedance spectroscopy (EIS) for 7 days in PBS. Biocompatibility and cytotoxicity were studied in mouse macrophages J774A.1 cell line by the measurement of mitochondrial activity (WST-1 assay) and plasma membrane damage (LDH assay). The inflammatory response was examined through TNF-α and IL-10 cytokines in macrophages culture supernatants, used as indicators of pro-inflammatory and anti-inflammatory responses, respectively. EIS diagrams of CoCrErGOHA revealed two time constants: the first one, attributed to the hydration and diffusion processes of the HA layer adsorbed on ErGO, and the second one, the corrosion resistance of ErGOHA/CoCr interface. Macrophage assays showed better behavior on CoCrErGOHA than CoCr and CoCrErGO surfaces based on their biocompatible, cytotoxic, and inflammatory responses. Comparative analysis of IL-10 showed that functionalization with HA induces higher values of anti-inflammatory cytokine, suggesting an improvement in inflammatory behavior. Full article

Our recent work on genetic epilepsy (GE) has identified common mechanisms between GE and neurodegenerative diseases including Alzheimer’s disease (AD). Although both disorders are seemingly unrelated and occur at opposite ends of the age spectrum, it is likely there are shared mechanisms and studies on GE could provide unique insights into AD pathogenesis. Neurodegenerative diseases are typically late-onset disorders, but the underlying pathology may have already occurred long before the clinical symptoms emerge. Pathophysiology in the early phase of these diseases is understudied but critical for developing mechanism-based treatment. In AD, increased seizure susceptibility and silent epileptiform activity due to disrupted excitatory/inhibitory (E/I) balance has been identified much earlier than cognition deficit. Increased epileptiform activity is likely a main pathology in the early phase that directly contributes to impaired cognition. It is an enormous challenge to model the early phase of pathology with conventional AD mouse models due to the chronic disease course, let alone the complex interplay between subclinical nonconvulsive epileptiform activity, AD pathology, and cognition deficit. We have extensively studied GE, especially with gene mutations that affect the GABA pathway such as mutations in GABA_A receptors and GABA transporter 1. We believe that some mouse models developed for studying GE and insights gained from GE could provide unique opportunity to understand AD. These include the pathology in early phase of AD, endoplasmic reticulum (ER) stress, and E/I imbalance as well as the contribution to cognitive deficit. In this review, we will focus on the overlapping mechanisms between GE and AD, the insights from mutations affecting GABA_A receptors, and GABA transporter 1. We will detail mechanisms of E/I imbalance and the toxic epileptiform generation in AD, and the complex interplay between ER stress, impaired membrane protein trafficking, and synaptic physiology in both GE and AD. Full article

Background: Chronic sympathetic nervous system activation is associated with endothelial dysfunction and cardiometabolic disease, which may be modulated by resveratrol (RSV) and energy restriction (ER). This study aimed to examine the effects of RSV and ER on plasma noradrenaline (NA), flow-mediated vasodilation (ed-FMD), and endothelium-independent nitrate-mediated vasodilation (ei-NMD). Methods: The study included 48 healthy adults randomized to 30-days intervention of RSV or ER. Results: Waist circumference, total cholesterol, HDL-c, LDL-c, apoA-I, and plasma NA decreased in the ER group, whilst RSV increased apoB and total cholesterol, without changing plasma NA. No effects on vascular reactivity were observed in both groups. Plasma NA change was positively correlated with total cholesterol (r = 0.443; p = 0.002), triglycerides (r = 0.438; p = 0.002), apoA-I (r = 0.467; p = 0.001), apoB (r = 0.318; p = 0.032) changes, and ei-NMD (OR = 1.294; 95%CI: 1.021–1.640). Conclusions: RSV does not improve cardiometabolic risk factors, sympathetic activity, and endothelial function. ER decreases plasma NA and waist circumference as well as improves blood lipids, but does not modify endothelial function. Finally, plasma NA was associated with ei-NMD, which could be attributed to a higher response to nitrate in patients with greater resting sympathetic vasoconstriction. Full article