In this study modeling different structures in perturbed Poiseuille flow in a nanochannel by using of molecular dynamics simulation was performed. Nanochannel limited by parallel Platinum plates ...containing an Argon fluid. We found that the wall roughness increases the velocity in the nanochannel by shrinking the cross-section. Also, the rectangular roughness and hemispherical roughness have the maximum and minimum effects on the flow properties, respectively. The other result is that the nanochannel roughness reduces the range of fluctuations near the walls. This is due to the fact that less fluid particles reside in the vicinity of the rough nanochannel walls compared the ideal nanochannel. Finally, changing the configuration of the nanochannel roughness from ellipsoid to hemi-spherical increases the number of Pt atoms in the structure and the simulated system; therefore, the total energy is also expected to increase.
•Modeling different structures in perturbed Poiseuille flow.•Study the equilibrium.•Using of molecular dynamics simulation.
In this paper, we investigate the effects of geometric shape of various roughnesses on the fluid flow passing through a nanochannel by using of molecular dynamics simulation. The results of ...simulations are presented for the modeled structures (the five models defined) as number density, velocity, and system temperature profiles for various conditions. By applying roughness to the inner surface of the ideal nano-channel at a thrust force of 0.002 eV/Å, the amplitude of number density of the fluid particles near the walls decreased, while the mean and maximum velocities increased by 6.5% and 2.5% in the presence of square cuboid and hemispheroid roughness, respectively. Furthermore, the dimensionless slip velocity and slip length were, respectively, increased by a maximum of 41.1% and 21.5% in the presence of square cuboid roughness and by a minimum of 0.9% and 0.5% in the presence of hemispheroid roughness. The temperature of the particles at the center of the nano-channel was increased by a maximum of 9.1% and a minimum of 2.8% in the presence of square cuboid and hemispheroid roughness, respectively. Calculation of the Argon-Argon radial distribution function indicated that the maximum of this function decreased by a maximum of 11.8% and a minimum of 8.5% in the presence of rectangular cuboid and ellipsoid roughness, respectively, compared to the ideal nano-channel.
•Effects of geometric shape of various roughnesses were investigated.•The results are presented for the five models.•Molecular dynamics simulation method was employed.•The open-source software, LAMMPS was used for simulation
The present study used molecular dynamics (MD) simulation to study the effects of external forces on the fluid flow passing through a nanochannel with different shapes of the interior wall. To this ...end, molecular dynamics simulation was employed to investigate the atomic arrangement and stability of the fluid inside a nanochannel in both presence and absence of rectangular and square cuboid, ellipsoid, and hemispheroid roughness. Moreover, the number density, velocity and temperature of argon flowing inside a Platinum nanochannel were investigated for a time step of 1,000,000 at external forces of 0.002, 0.0018, 0.0017, and 0.0014 eV/Å. The results obtained for each of the aforementioned models were compared with respect to the different thrust forces. Our results show that as the driving force increases from 0.0014 to 0.002 eV/Å, the velocity at the center of the nanochannel is increased approximately from 1.7 to 3.6 Å/ps while the velocity near the wall increases approximately from 0.5 to 1.4 Å/ps. Also, the temperature at the center of the nanochannel increases approximately from 355.2 to 536 K while the temperature near the wall increases approximately from 206.5 to 237.6 K.
•Effects of external force on the fluid flow passing through a rough nanochannel.•Different shapes of the interior wall.•Using molecular dynamics simulation.
•Effect of sodium silicate to sodium hydroxide ratio and RCA were determined.•The higher SS/SH ratio, the lower the chloride ion permeability and absorption.•Deboning width at ITZ between RCA-binder ...decreased with the increase of SS/SH.•Polymer products in the proximity of adequate monomer ratios became uniform.
Properties of geopolymer concrete using metakaolin (MK) as the aluminosilicate source and recycled concrete aggregate (RCA) as partial replacement of natural aggregate are presented in this paper. The effects of sodium silicate (SS) to sodium hydroxide (SH) ratios, and RCA in different percentages on the mechanical and durability properties of geopolymer concrete were determined. Microstructural changes of geopolymers as a result of using RCA were evaluated via scanning electron microscopic (SEM) images. Test results showed that compressive strength of geopolymer concrete improved with increasing the SS/SH ratio. Although the use of RCA reduced compressive strength by up to 28%, the strength was still high enough for structural applications. In addition, increasing the SS/SH ratio reduced the chloride ion permeability and absorption of geopolymer concrete. The morphology results showed that the deboning width at the interfacial transition zone (ITZ) between RCA and binder decreased with the increase of SS/SH ratio. The polymer products in the proximity of adequate monomer ratios became more uniform and homogenous. Results also showed that the binder with a SS/SH ratio of 3 exhibited higher density and less porosity than that with smaller ratios. Therefore, the recycled construction and demolition waste can significantly contribute to the sustainability of construction industry from technical, economic and environmental points of view.
This paper presents an experimental study on a new mixture scheme of mortar. Unlike most of existing work, the present study investigates nano-CuO (NC), and its combined effects with cement ...replacement i.e., rice husk ash (RHA) on durability performance, as well as strength and permeability properties of mortars. Comprehensive observations of both the performance and properties improvements on RHA-containing mortar specimens were determined with the addition of NC. To this end, a series of tests for examining the strength both directly (compressive strength) and indirectly (Ultrasonic Pulse Velocity), electrical resistivity, chloride permeability, water absorption and microstructure characteristics (i.e., SEM micrographs, Mercury intrusion porosimetry (MIP) & capillary analyses) of mortar specimens were performed. A relationship between the Rapid chloride permeability test (RCPT) and electrical resistivity was also studied in order to recommend an alternative method for quality control in the presence of RHA and NC. Finally, a mixture scheme which provides relatively satisfactory properties improvement with positive environment credential is suggested.
•Both single and combine effects of NC and RHA on mortar properties are reported.•Binary combination of NC and RHS markedly improves performance and properties of mortar.•A relationship between the RCPT and electrical resistivity was studied for quality control.•The opposite effects caused by RHA and nano-CuO on porosity and sorptivity are quantitatively discussed.•RHA20NC3 provides satisfactory properties improvement with positive environment credential.
The aim of this study was to compare outcomes between cases of Acanthamoeba keratitis (AK) diagnosed and treated with or without the use of in vivo confocal microscopy (IVCM).
We performed a ...retrospective comparative case series of 26 eyes of 23 patients diagnosed with AK at the Massachusetts Eye and Ear Infirmary over a 5-year period. The characteristics of all identified cases were summarized. We compared the time from presentation to diagnosis of AK (primary outcome), visual acuity, and rates of therapeutic penetrating keratoplasty between eyes diagnosed by culture-only group (n = 8) and by IVCM to diagnose AK (n = 9) and later confirmed by culture (IVCM/C group).
The diagnostic delay was significantly longer in the culture only group (25 ± 29 days) compared with the IVCM/C group (3 ± 3 days, P < 0.01). At 6 months, there was a significant difference in best-corrected visual acuity between the culture-only group (1.46 ± 1.07, n = 7) and the IVCM/C group (0.22 ± 0.22, n = 8), after adjusting for initial baseline visual acuity (P = 0.02). Therapeutic penetrating keratoplasty was performed in 50% of culture-only (n = 7) and 11% of IVCM/C group eyes (n = 9), but this was not statistically significant (P = 0.13).
IVCM can expedite the diagnosis of AK, and its use as an adjunct tool in the diagnosis of AK may result in better patient outcomes compared with basing treatment decisions on corneal cultures alone.
Among different topical drug delivery systems, nanoemulsions (NEs) are attractive due to enhanced skin permeation potential and minimum toxicity. Topical nanoemulgels (NEMGELs) contain both gelling ...agents and NEs and thus can enhance skin permeation with sustained effects at the site of application. Oxybutynin (OXB) is an anti-muscarinic agent that is administered orally to treat hyperhidrosis but its systemic side effects may decrease patient compliance. Therefore, it assumes that oxybutynin-nanoemulgel (OXB-NEMGEL) with sustained release properties and skin permeation ability may be a suitable alternative. Using Design Expert software
®
, 17 OXB-NE formulations were prepared and optimized based on particle size, zeta potential and physical stability. Three polymers were used to prepare and optimized OXB-NEMGEL based on spreadability and viscosity.
In-vitro
drug release and
ex-vivo
skin permeation were investigated for optimized formulation. The model suggested by Design-Expert was quadratic and there was significant association between response variables including particle size and zeta potential and independent variables (Oil:Surfactant ratio, Oil:Water ratio, and surfactants HLB) with P-values of 0.0334 and 0.0173, respectively. Also, the lack of fit was not significant (P-values 0.057 and 0.569, respectively) which confirms the fitness of this model. Average size and zeta potential of optimized nanoemulsions were 99 ± 0.1 nm and -57.3 ± 0.5 mv, respectively. Carboxymethyl cellulose-based nanoemulgels (CMC-NEMGEL) showed acceptable viscosity with a shear thinning rheological pattern and good spreadability which released OXB within 8 h.
Ex-vivo
OXB skin permeation revealed OXB flux of 1.5 ± 0.3 and 3.6 ± 0.2 μg/cm
2
/h after 12 and 24 h, respectively, which was equal to 5.3 ± 1.1% and 11.9 ± 0.7% of drug, while simple OXB gel did not permeate through skin layers. Thus, OXB-NEMGEL with effective skin permeation potential would be a novel promising drug delivery system for hyperhidrosis management which may lower systemic side effects.
•miR-155 is obviously upregulated in PBMCs of MS patients.•There is a positive correlation between miR-155 expression with increased frequency of Th17 cells in MS patients.•There is a positive ...correlation between miR-155 expression with increased secreted levels of Th17 related inflammatory cytokines including IL-6, IL-17 and IL-21 in serum of MS patients.•miR-155 can be targeted as a promising therapeutic strategy for the management and prevention of MS occurrence and progression.
In the chronic, organ-specific autoimmune disorder known as multiple sclerosis (MS), the myelin sheath is attacked by immune cells, leading to damage to the central nervous system (CNS). It has been discovered that miRNAs are important in the etiology of MS, since deregulation of miRNAs can lead to defects in immune tolerance. In this study, we sought to investigate the involvement of miR-155 in MS disorder through examination of its altered expression in peripheral blood mononuclear cells (PBMCs) of patients with MS in compare with healthy controls. Furthermore, we investigated the frequency of T helper 17 cells (Th17) in MS patients and analyzed not only the expression of inflammatory cytokines including IL-6, IL-17 and IL-21 in patients’ PBMCs, but also their secreted levels in serum of patients suffering from MS. Subsequently, we assessed the correlation between miR-155 expression with Th17 frequency and levels of released cytokines in serum. Upregulated expression of miR-155 was detected in PBMCs of MS patients and the positive correlation between its expression with increased frequency of Th17 cells and their related inflammatory cytokine profile augmented secretion in serum were identified. In conclusion, our study revealed the significant association between Th17 frequency, increased level of cytokines related to Th17 differentiation and function with miR-155 augmented expression in PBMCs. So, our findings suggested that miR-155 and especially its expression in immune cells including effector T cells can be the target of future therapeutic strategies for the management and prevention of MS progression, however, further research is requisite before this approach can be utilized in clinical practice.
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Dendritic cells (DCs) are professional antigen-presenting cells (APCs), including heterogenous populations with phenotypic and functional diversity that coordinate bridging innate and adaptive ...immunity. Signal transducer and activator of transcriptions (STAT) factors as key proteins in cytokine signaling were shown to play distinct roles in the maturation and antigen presentation of DCs and play a pivotal role in modulating immune responses mediated by DCs such as differentiation of T cells to T helper (Th) 1, Th2 or regulatory T (Treg) cells. This review sheds light on the importance of STAT transcription factors' signaling pathways in different subtypes of DCs and highlights their targeting potential usages for improving DC-based immunotherapies for patients who suffer from cancer or diverse autoimmune conditions according to the type of the STAT transcription factor and its specific activating or inhibitory agent.
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