In a few last decades, equal-channel angular pressing (ECAP) has been one of the most prominent procedures for fabrication of ultrafine-grained (UFG) structures among various severe plastic ...deformation (SPD) techniques. The objective of this paper is to experimentally investigate the influence of longitudinal ultrasonic vibrations on the ECAP process. A robust experimental ECAP system was designed and manufactured, in which the punch can be excited by ultrasonic vibrations. ECAP experiments were carried out with and without ultrasonic vibration on pure Al. The microstructure of the specimens formed with ultrasonic-assisted ECAP and conventional ECAP were studied. The results of this study showed that superimposing ultrasonic vibrations on the ECAP process could improve the grain refinement efficiency. The grains of the specimens after conventional ECAP process were refined to 45 μm, while by applying ultrasonic vibration with amplitudes of 2.5 and 5 μm, the grains were refined to 28.2 and 22 μm , respectively. Using higher vibration amplitudes caused more refinement of the grains. The homogeneity of the microstructure after four passes of ECAP was also improved by 26.7 % while using ultrasonic vibration with amplitude of 2.5 μm. Higher vibration amplitudes made a more homogenous structure. The yield strength and ultimate tensile strength of the specimens after one pass of ECAP were higher in comparison with the conventional ECAP.
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DOBA, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, IZUM, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, SIK, UILJ, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Traditional risk factors of cardiovascular death in the general population, including body mass index (BMI), serum cholesterol, and blood pressure (BP), are also found to relate to outcomes in the ...geriatric population, but in an opposite direction. Some degrees of elevated BMI, serum cholesterols, and BP are reportedly associated with lower, instead of higher, risk of death among the elderly. This phenomenon is termed "reverse epidemiology" or "risk factor paradox" (such as obesity paradox) and is also observed in a variety of chronic disease states such as end-stage renal disease requiring dialysis, chronic heart failure, rheumatoid arthritis, and AIDS. Several possible causes are hypothesized to explain this risk factor reversal: competing short-term and long-term killers, improved hemodynamic stability in the obese, adipokine protection against tumor necrosis factor-α, lipoprotein protection against endotoxins, and lipophilic toxin sequestration by the adipose tissue. It is possible that the current thresholds for intervention and goal levels for such traditional risk factors as BMI, serum cholesterol, and BP derived based on younger populations do not apply to the elderly, and that new levels for such risk factors should be developed for the elderly population. Reverse epidemiology of conventional cardiovascular risk factors may have a bearing on the management of the geriatric population, thus it deserves further attention.
In the current study mixed matrix heterogeneous cation exchange membranes were prepared by solution casting technique. The effect of SiO(2) nanoparticles in the polymeric solution on the ...physicochemical properties of prepared membranes was studied. Scanning optical microscope images showed uniform particle distribution and relatively uniform surfaces for the prepared membranes. The membrane water content was reduced by silica nanoparticles in the membranes' matrix. The membrane ion exchange capacity, membrane potential, transport number and selectivity were improved initially by an increase of SiO(2) nanoparticles concentration up to 1%wt in prepared membranes and then showed a decreasing trend with a further increase in additive ratio from 1 to 4%wt. The ionic permeability and flux were also decreased initially by an increase of silica nanoparticles concentration up to 0.5%wt in the membrane matrix and then increased again with a further increase in nanoparticles concentration from 0.5 to 4%wt. Moreover, the results exhibited that using silica nanoparticles in the membrane matrix caused an obvious decrease in areal electrical resistance. The opposite trend was found for membrane mechanical strength using SiO(2) nanoparticles.
The existence of imbalanced single- and two-phase loads, coupled with short-circuit faults, contributes to voltage imbalance. It is inevitable to use LCL filters to remove harmonics caused by ...converter switching. While effective in removing harmonic components, these filters may inadvertently amplify and propagate resonance. Both voltage imbalance and active resonance significantly degrade power quality. This paper proposes a multi-level hierarchical control system to mitigate both phenomena. At Level 1, the controller incorporates proportional-resonant regulators for current and voltage. Level 2 employs common droop control to establish microgrid voltage and frequency reference values. Level 3 introduces a washout filter with an adjustable Kd gain, capable of attenuating active resonance harmonics originating from the LCL filter. Finally, Level 4 integrates a controller based on extracting positive and negative sequence components using the dual decoupled synchronous reference frame (DDSRF) algorithm. This controller effectively compensates for negative sequence components of voltage in the load bus, balancing load voltage. Simulation results for a standalone microgrid demonstrate that the proposed 4-level hierarchical control algorithm can reduce the load bus voltage imbalance from 10% to 2.5% under the most challenging conditions. It diminishes harmonic distortion caused by active resonance from 11% to 2.5%. The presented control algorithm can perform optimally under dynamic changes of active and reactive power of nonlinear and imbalanced loads. The main merit of this approach is not to use physical devices and Flexible Alternative Current Transmission Systems (FACTS), such as Active Power Filters (APF), Distribution Static Synchronous Compensators (DsSTATCOM), SVC, etc.
The complex reconstructive surgeries for which patient-specific orthopedic, maxillofacial, or dental implants are used often necessitate wounds that are open for a considerable amount of time. ...Unsurprisingly, this allows bacteria to establish implant-associated infection, despite the scrupulous sterilization efforts made during surgery. Here, we developed a prophylactic bactericidal coating via electrophoretic deposition technology for two 3D-printed porous titanium implant designs. The surface characteristics, antibiotic release behavior, antibacterial properties, and impact on osteoblast cell proliferation of the optimized coatings were investigated. The results unequivocally confirmed the biofunctionality of the implants in vitro. This study reveals a new avenue for future antibacterial patient-specific implants.
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IJS, KILJ, NUK, PNG, UL, UM
During past two decades, plant-derived bioactive compounds have been reported as novel therapeutic agents for prevention and/or mitigation of different human diseases such as cancer, inflammation, ...cardiovascular and neurodegenerative diseases. Hesperidin is known as one of the most common and bioactive constituents of Citrus (C) species which possesses multiple health-promotion effects. A plethora of scientific literature reported that hesperidin possesses in-vitro and in-vivo anticancer activities. In addition, there are numerous scientific evidences regarding the molecular mechanisms of anticancer activities of hesperidin and its aglycone, hesperetin. However, in this case, the number of comprehensive reviews on molecular mechanisms underlying the anticancer effects of hesperidin is sparse. Therefore, in this work we present a critical review of the available literature regarding the molecular mechanisms of the anticancer effects of hesperidin and its aglycone, hesperetin.
A heterogeneous anion exchange membrane was modified by introducing polyaniline nanoparticles, in order to enhance its electrochemical properties in view of chloride and sulfate ion removal from ...water. Polyaniline nanoparticles were synthesized by facile chemical polymerization technique. Nanoparticles were characterized by FTIR, FESEM, and XRD. In addition, SOM images showed a uniform surface for membranes. Utilizing PANI nanoparticles in membrane body led to increase of water content, ion exchange capacity, surface hydrophilicity, and electrical conductivity. Membrane transport number and permselectivity were improved in NaCl solution by incorporating PANI nanoparticles; in Na
2
SO
4
solution, they showed an opposite trend. The chloride and sulfate flux were enhanced by a low PANI concentration and declined at higher concentration. Modified PANI membranes showed a lower selectivity and flux for bivalent ions compared to monovalent ions. Membrane mechanical resistance was increased by using PANI in concentrations up to 2 wt% and decreased at higher PANI ratios.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OBVAL, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Non-coding RNAs (ncRNAs) are a diverse group of functional RNA molecules that lack the ability to code for proteins. Despite missing this traditional role, ncRNAs have emerged as crucial regulators ...of various biological processes and have been implicated in the development and progression of many diseases, including cancer. MicroRNAs (miRNAs) and long non-coding RNAs (lncRNAs) are two prominent classes of ncRNAs that have emerged as key players in cancer pathophysiology. In particular, miR-21 has been reported to exhibit oncogenic roles in various forms of human cancer, including prostate, breast, lung, and colorectal cancer. In this context, miR-21 overexpression is closely associated with tumor proliferation, growth, invasion, angiogenesis, and chemoresistance, whereas miR-21 inactivation is linked to the regression of most tumor-related processes. Accordingly, miR-21 is a crucial modulator of various canonical oncogenic pathways such as PTEN/PI3K/Akt, Wnt/β-catenin, STAT, p53, MMP2, and MMP9. Moreover, interplays between lncRNA and miRNA further complicate the regulatory mechanisms underlying tumor development and progression. In this regard, several lncRNAs have been found to interact with miR-21 and, by functioning as competitive endogenous RNAs (ceRNAs) or miRNA sponges, can modulate cancer tumorigenesis. This work presents and discusses recent findings highlighting the roles and pathophysiological implications of the miR-21-lncRNA regulatory axis in cancer occurrence, development, and progression. The data collected indicate that specific lncRNAs, such as MEG3, CASC2, and GAS5, are strongly associated with miR-21 in various types of cancer, including gastric, cervical, lung, and glioma. Indeed, these lncRNAs are well-known tumor suppressors and are commonly downregulated in different types of tumors. Conversely, by modulating various mechanisms and oncogenic signaling pathways, their overexpression has been linked with preventing tumor formation and development. This review highlights the significance of these regulatory pathways in cancer and their potential for use in cancer therapy as diagnostic and prognostic markers.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
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