Spectral efficiency (SE) enhancement of NOMA system through iterative power assignment

Wireless Networks - This paper studies enhancing non-orthogonal multiple access (NOMA) spectral efficiency (SE) through optimizing the assigned power to each NOMA user depending on their channel...     

Self-cleaning antireflected surfaces based on treated PEO/SiO2 nanocomposite films

In this study, the polyethylene oxide (PEO)/SiO₂ nanoparticles (NPs) nanocomposite films with various SiO₂ NPs concentrations were prepared using an in situ formation of NPs in the polymer matrix for self-cleaning antireflected surface applications. The effect of SiO₂ NPs in PEO/SiO₂ NPs nanocomposite films on the structural, morphological, chemical, thermal, optical, and electrical properties of PEO/SiO₂ NPs nanocomposite films was performed. According to the x-ray diffraction and the differential scanning calorimetry analysis, the crystallinity degree of the nanocomposite films decreases by increasing the SiO₂ NPs concentrations. The bandgap energy of PEO/SiO₂ NPs nanocomposite films decreases from 3.95 to 3.55 eV as the SiO₂ NPs concentration increases up to 10 wt.%. The average electrical conductivity of the PEO/SiO₂ NPs nanocomposite films increases from 5.1 × 10⁻⁷ to 2.0 × 10⁻⁶ S/cm as the SiO₂ NPs concentration increases up to 10 wt.%. The refractive index decreases to 1.64 at 550 nm for the PEO/SiO₂ NPs nanocomposite films with 10 wt.% of SiO₂ NPs, and the water contact angle decreases to around 0° after thermal treatment, which confirms that the PEO/SiO₂ NPs nanocomposite films can be used as self-cleaning antireflected surfaces.     

Luminescent Amphiphilic Aminoglycoside Probes to Study Transfection

We report the characterization of amphiphilic aminoglycoside conjugates containing luminophores with aggregation-induced emission properties as transfection reagents. These inherently luminescent transfection vectors are capable of binding plasmid DNA through electrostatic interactions; this binding results in an emission “on” signal due to restriction of intramolecular motion of the luminophore core. The luminescent cationic amphiphiles effectively transferred plasmid DNA into mammalian cells (HeLa, HEK 293T), as proven by expression of a red fluorescent protein marker. The morphologies of the aggregates were investigated by microscopy as well as ζ-potential and dynamic light-scattering measurements. The transfection efficiencies using luminescent cationic amphiphiles were similar to that of the gold-standard transfection reagent Lipofectamine® 2000.     

Behavioural alterations induced by chronic exposure to 10 nm silicon dioxide nanoparticles

Silicon dioxide nanoparticles (SiO₂ NPs) are widely invested in medicine, industry, agriculture, consuming products, optical imaging agents, cosmetics, and drug delivery. However, the toxicity of these NPs on human health and the ecosystem have not been extensively studied and little information is available about their behavioural toxicities. The current study aimed to find out the behavioural alterations that might be induced by chronic exposure to 10 nm SiO₂ NPs. BALB/C mice were subjected to 36 injections of SiO₂ NPs (2 mg/kg Bw) and subjected to 11 neurobehavioural tests: elevated plus‐maze test, elevated zero‐maze test, multiradial maze test, open field test, hole‐board test, light‐dark box test, forced swimming test, tail‐suspension test, Morris water‐maze test, Y‐maze test and multiple T‐maze test. Treated mice demonstrated anxiety‐like effect, depression tendency, behavioural despair stress, exploration and locomotors activity reduction with error induction in both reference and working memories. The findings may suggest that silica NPs are anxiogenic and could aggravate depression affecting memory, learning, overall activity and exploratory behaviour. Moreover, the findings may indicate that these nanomaterials (NMs) may induce potential oxidative stress in the body leading to neurobehavioural alterations with possible changes in the vital organ including the central nervous system.     

Synthesis Optimization of Piezo Driven Four Bar Mechanism Using Genetic Algorithm

Over the past few years, there has been a growing demand to develop efficient precision mechanisms for fine moving applications. Therefore, several piezoelectric driven mechanisms have been proposed for such applications. In this work an optimal synthesis of a four-bar mechanism with three PEAs is proposed. Two evolutionary multi-objective Genetic Algorithms (GAs) are formulated and applied; A Genetic Algorithm Synthesis method (GAS) is first used to obtain a synthesis solution for the mechanism regardless of power consumption. Then another Genetic Algorithm Minimum Power Synthesis method (GAMPS) is used to obtain the synthesis solution of minimum power consumption. For that purpose, the study performs simulation investigation of the aforementioned algorithms for each point along sinusoidal and kidney shaped paths of motion. Results show capability of both methods in obtaining a synthesis solution. However, GAMPS outperformed GAS in terms of driving power consumption as it is minimized by 99% ratio.     

New approach to gas pressure profile prediction for high temperature AA5083 sheet forming

A new theoretical approach to the prediction of gas pressure profiles that vary smoothly with time in high temperature forming of fine-grained AA5083 sheet is presented. The required pressure-flow stress relationship, which couples the gas pressure profile and the material constitutive model, was implemented in ABAQUS implicit. Forming of a rectangular pan in a die with variable entry radii was simulated with a single creep mechanism model that accounts for hardening/softening in AA5083. Predicted sheet thickness and thinning in a die entry radius region at the end of forming are examined in detail. Results are compared with those from two additional gas pressure schemes. One of these is taken directly from experiments and the other is based upon an algorithm that is internal to ABAQUS. The effect of friction on forming time is explored in the absence of a stability criterion for necking.     

Hepatic histopathological and ultrastructural alterations induced by 10 nm silver nanoparticles

Silver nanoparticles (Ag NPs) are invested in various sectors and are becoming more persistent in our ambient environment with potential risk on our health and the ecosystems. The current study aims to investigate the histological, histochemical and ultrastructural hepatic changes that might be induced by 10 nm silver nanomaterials. Male mice (BALB/C) were exposed for 35 injections of daily dose of 10 nm Ag NPs (2 mg/kg). Liver tissues were subjected to examination by light and electron microscopy for histological, histochemical and ultrastructural alterations. Exposure to Ag NPs induced Kupffer cells hyperplasia, sinusoidal dilatation, apoptosis, ground glass hepatocytes appearance, nuclear changes, inflammatory cells infiltration, hepatocytes degeneration and necrosis. In addition, 10 nm Ag NPs induced histochemical alterations mainly glycogen depletion with no hemosiderin precipitation. Moreover, these nanomaterials exhibited ultrastructure alterations including mitochondrial swelling and cristolysis, cytoplasmic vacuolation, apoptosis, multilammellar myelin figures formation and endoplasmic destruction and reduction. The findings revealed that Ag NPs can induce alterations in the hepatic tissues, the chemical components of the hepatocytes and in the ultrastructure of the liver. One may also conclude that small size Ag NPs, which are increasingly used in human products could cause various toxigenic responses to all hepatic tissue components.Inspec keywords: liver, electron microscopy, molecular biophysics, optical microscopy, toxicology, biochemistry, silver, biological tissues, nanofabrication, cellular biophysics, biomedical materials, nanoparticles, nanomedicineOther keywords: hepatic histopathological alterations, ultrastructural alterations, silver nanoparticles, histological changes, histochemical changes, ultrastructural hepatic changes, silver nanomaterials, male mice, liver tissues, electron microscopy, histological alterations, histochemical alterations, Kupffer cells hyperplasia, sinusoidal dilatation, apoptosis, ground glass hepatocytes appearance, inflammatory cells infiltration, hepatocyte degeneration, necrosis, ultrastructure alterations, Ag, size 10.0 nm, hepatic tissue components, cytoplasmic vacuolation     

Effect of hydrogen-related shallow donor on the physical and chemical properties of Ag-doped ZnO nanostructures

Journal of Materials Science: Materials in Electronics - Silver-doped zinc oxide nanostructures (Ag/ZnO NSs) with Ag content of 0 wt%, 5 wt%, 10 wt%, and 20 wt% were synthesized using a...     

Surgical treatment of fixed subvalvular aortic stenosis. Immediate and long-term hemodynamic results

Forty patients operated on for fixed subvalvular aortic stenosis underwent cardiac catheterization preoperatively, immediately after coming off cardiopulmonary bypass and at long-term (1 to 14 years later, average 7 +/- 3.9 years). The age range was 3 to 50 years (average 15 +/- 12 years) with 27 (68%) aged under 18 years. Twenty-seven patients were male. The stenosis was the thin membranous type in 29, the fibromuscular collar type in 5, the tunnel type in 5 others and related to supernumerary mitral tissue in the remaining patient. Significant other pathology was associated in 13 cases. In addition to excision of the membrane or the fibromuscular ring, the surgeons performed myotomy in 6 cases, myomectomy in 12 cases, large resection of muscular and fibrous tissue in tunnels, and aortic valve replacement in 3 cases. There was no operative fatality. Permanent cardiac pacing was required in 1 patient for complete atrioventricular block. The peak systolic pressure gradient fell from 87 +/- 32 to 31 +/- 10 mmHg (p < 0.0001) at the immediate control: it remained > 30 and even 50 mmHg in 3 patients (7.5%), 2 of whom had tunnel types and the other the supernumerary mitral tissue. The gradient increased in the long-term to 42 +/- 11 mmHg, 1 patient with a membrane developed a gradient of 40 mmHg and 4 others (10%) developed a gradient > 50 mmHg (3 tunnels and 1 membrane). The 5 patients with tunnel types either had a residual stenosis or restenosis and underwent aorto-ventriculoplasty by Konno's procedure 1 to 8 years later. This operation should be the procedure of first intention, even in small children: the large resection is only acceptable when it cannot be performed or when aortic ring hypoplasia is mild. There is no residual stenosis and restenosis is rare (2.5%) in the membranous and fibromuscular types, probably because of the widespread use of myotomy and myomectomy. In the absence of severe associated malformations, surgery in only justified when peak systolic pressure gradients are > or = 50 mmHg.     

Active polarizer dimmable lens system

Display units that utilize a dimmable smart lens may be utilized to reduce the required display luminance compared with a smoked neutral density lens to provide a hidden display appearance. A lens configuration that utilizes an active polarizer in conjunction with a linear polarizer is explored.