Micromachining of amplitude and phase modulated reflective computer generated hologram patterns in silicon

Silicon has been machined on lateral resolutions of micrometers and on depth resolutions of nanometers using a recently-developed process based on ion irradiation and electrochemical anodisation. Here we investigate its use as a recording medium for computer generated hologram patterns. We describe the fabrication of both amplitude and phase binary modulated reflective computer generated hologram patterns on a silicon surface with pixel sizes of 5 μm. We further discuss the use of micromachined silicon to variably modulate both amplitude and phase in a continuous, rather than a binary fashion.     

Hydrothermal synthesis of nickel iron oxide nano-composite and application as magnetically separable photocatalyst for degradation of Solar Blue G dye

In this research, nickel iron oxide nano-composite was effectively prepared via a simple hydrothermal route in an autoclave at 180?°C. The phase formation and opto-elctronic properties of nano-composite were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), energy dispersive X-ray spectroscopy (EDX), Fourier transform infrared spectroscopy (FTIR), UV–Vis diffuse reflectance spectra (UV–Vis DRS) and vibrating sample magnetometer (VSM) techniques. The VSM reults showed magnetization value of 38.25 emu/g. FTIR and XRD results confirmed the formation of cubic NiFe₂O₄ and rhombohedral Fe₂O₃ phases. The results of FESEM and EDAX studies indicate the formation of nickel iron oxide nano-composite with size of 7–10 nm. UV–Visible diffuse reflectance spectra experimental results showed transition energies of 1.66, 2.5 and 3.7 eV. Additionally, the prepared nickel iron oxide nano-composite were used as photocatalyst for for degradation Solar Blue G dye and the results showed good activity and recyclable by applying an appropriate magnetic field. The reuse of the prepared nickel iron oxide nano-composite for removal of Solar Blue G dye water pollutants was attained in five cycles with an average efficiency of 81%.     

Highly enhanced photocatalytic performance of Zn(1−x)MgxO/rGO nanostars under sunlight irradiation synthesized by one-pot refluxing method

The current research presents a simple, coast-effective, and one-pot refluxing method to synthesize Zn_(1?x)Mg_xO nanostructures, which were decorated on graphene oxide (GO) sheets. In the first step, the effect of refluxing time on structure and morphology of the pristine ZnO nanostructures was investigated. X-ray diffraction (XRD) patterns indicated that the pristine ZnO nanostructures were formed after 8?h of the refluxing process. Field emission electron microscope (FESEM) images showed that stars-shape ZnO nanostructures were formed after 10?h of refluxing time. Further refluxing process for 12?h showed that morphology and structure of the ZnO nanostructures were not changed. However, after 14?h additional phases were formed. Therefore, ZnO and Zn_(1?x)Mg_xO nanostars that were decorated on GO sheets were synthesized during 10?h. XRD patterns indicated that GO sheets were changed into reduced graphene oxides (rGO) during the refluxing process. Transmission electron microscope (TEM) images revealed that ZnO nanostars with more branches were decorated on rGO sheets. However, the TEM images showed that the morphology of Zn_xMg_(1?x)O/rGO nanocomposites were changed significantly with the increase of Mg concentration up to 6%. Photocatalytic performance of the products was examined under natural sunlight irradiation. The results showed that the rGO and Mg concentrations had significant roles in the photocatalytic performance of ZnO nanostars. The concentrations of Mg and rGO increased up to 4% were the optimum concentration for enhancing photocatalytic performance of Zn_(1?x)Mg_xO/rGO nanocomposites. In addition, room temperature photoluminescence (PL) spectroscopy and photocurrent measurement results indicated that Mg and rGO with optimum concentration caused decrease of electron-hole recombination rate.     

The effectiveness of cost-effectiveness analysis in containing costs

OBJECTIVE: Although cost-effectiveness analyses (CEAs) have been advocated as a tool to critically appraise the value of health expenditures, it has been widely hoped that they might also help contain health care costs. To determine how often they discourage additional expenditures, we reviewed the conclusions of recently published CEAs. DATA SOURCES: A search of the Abridged Index Medicus (a subset of MEDLINE designed to afford rapid access to the literature of "immediate interest" to the practicing physician) between 1990 and 1996. STUDY SELECTION: We only included articles that reported an explicit cost-effectiveness (CE) ratio (a cost for some given health effect) in the abstract. DATA ABSTRACTION: From each abstract, we collected the value for the incremental CE ratio and the measure of health effect (life-years, quality-adjusted life-years [QALYs], other). We then categorized the authors' conclusion into one of three categories: supports strategy requiring additional expenditure, no firm conclusion, and supports low-cost alternative. Finally, we obtained the article and collected information on funding source. DATA SYNTHESIS: Among the 109 eligible articles, the authors' conclusion supported strategies requiring additional expenditure in 58 (53%) and supported the low-cost alternative in 28 (26%). We then focused on the 65 articles reporting either life-years or QALYs. Cost-effectiveness ratios ranged from $400 to $166,000 (per life-year or QALY) in the 39 articles (60%) in which authors supported additional expenditure, and ranged from $61,500 to $11,600,000 in the 13 articles (20%) in which authors supported the low-cost alternative. Despite identifying similar CE ratios, authors arrived at different conclusions in the overlapping range ($61,500 to $166,000). Of the 10 articles acknowledging industry funding, 9 supported a strategy requiring additional expenditure (p = .01 as compared with those without such funding). CONCLUSIONS: Authors of CEAs are more likely to support strategies requiring additional expenditure than the low-cost alternative. There is no obvious consensus about how small the CE ratio should be to warrant additional expenditure. Finally, concerns about funding source seem to be warranted.     

Formation of homogenous nanofibers using silicon microneedle spinnerets

We report the use of a silicon microfabricated device as a new spinneret for electrospinning purposes. This device has been realized on silicon substrates using a deep reactive ion etching process. To make proper holes in the center of microneedles, a rotating angle deposition method followed by vertical etching of silicon is employed. By using these needles as fluid nozzles in the electrospinning process, poly vinyl alcohol solution with a concentration of 7?% has been converted into nanofibers. The formation of nanofibers has been investigated using field emission scanning electron microscopy. Using this process, nanofibers with a diameter of 100–200?nm are realized where the dispersion is less than 50?nm. Finally, the effects of needle size and the applied voltage have been investigated on the diameter of nanofibers.     

A Review on the Role of Non-Coding RNAs in the Pathogenesis of Myasthenia Gravis

Myasthenia gravis (MG) is an autoimmune condition related to autoantibodies against certain proteins in the postsynaptic membranes in the neuromuscular junction. This disorder has a multifactorial inheritance. The connection between environmental and genetic factors can be established by epigenetic factors, such as microRNAs (miRNAs) and long non-coding RNAs (lncRNAs). XLOC_003810, SNHG16, IFNG-AS1, and MALAT-1 are among the lncRNAs with a possible role in the pathoetiology of MG. Moreover, miR-150-5p, miR-155, miR-146a-5p, miR-20b, miR-21-5p, miR-126, let-7a-5p, and let-7f-5p are among miRNAs whose roles in the pathogenesis of MG has been assessed. In the current review, we summarize the impact of miRNAs and lncRNAs in the development or progression of MG.     

Modeling lead input and output in soils using lead isotopic geochemistry

The aim of this study is to model downward migration of lead from the plow layer of an experimental site located in Versailles (about 15 km southwest of Paris, France). Since 1928, samples have been collected annually from the topsoil of three control plots maintained in bare fallow. Thirty samples from 10 different years were analyzed for their lead and scandium contents and lead isotopic compositions. The fluxes are simple because of the well-controlled experimental conditions in Versailles: only one output flux, described as a first-order differential function of the anthropogenic lead pool, was taken into account; the inputs were exclusively ascribed to atmospheric deposition. The combination of concentration and isotopic data allows the rate of migration from the plowed topsoil to the underlying horizon and, to a lesser extent, the atmospheric fluxes to be assessed. Both results are in good agreement with the sparse data available. Indeed, the post-depositional migration of lead appears negligible at the human time scale: less than 0.1% of the potentially mobile lead pool migrates downward, out of the first 25 cm of the soil, each year. Assuming future lead inputs equal to 0, at least 700 yr would be required to halve the amount of accumulated lead pollution. Such a low migration rate is compatible with the persistence of a major anthropogenic lead pool deposited before 1928. Knowledge of pollution history seems therefore to be of primary importance.     

Exfoliated and plicated g-C3N4 nanosheets for efficient photocatalytic organic degradation and hydrogen evolution

Exfoliated and plicated g-C₃N₄ nanosheets (CNsF) were prepared through a thermal-chemical exfoliation in which the bulk g-C₃N₄ was obtained first under thermal exfoliation, and then was exposed to an acidic etching using hydrofluoric acid under hydrothermal condition. The acidic etching not only exfoliated g-C₃N₄ nanosheets by disrupting weak van der Waals forces between layers, which led to formation of a monolayer or a few layers of g-C₃N₄ nanosheets, but also made disordered defects on its surface and created plicated g-C₃N₄ nanosheets. Under visible-light illumination, the optimized sample (CNsF-6%) showed a hydrogen evolution rate of 54.13 μmol h^?1g^?1 (without co-catalyst) and a specific surface area of 121.4 m² g^?1, which were about 4.7 and 2.5 times, respectively, higher than pristine g-C₃N₄. It also showed remarkably enhanced photocatalytic performance in removing various organic pollutants. This remarkable improvement probably arises from the porous nanosheets and an increased number of active sites resulting from the CNsF, which subsequently enhanced the charge separation efficiency. This work provided an alternative way to obtain highly active g-C₃N₄ photocatalysts.     

Seismic optimal design of 3D steel frames using cuckoo search algorithm

The present article is concerned with optimization of real size 3D steel structures under seismic loading based on response spectral and equivalent static analyses. The effect of lateral seismic loading distribution on the achieved optimum designs is investigated. An integrated optimization procedure with the objective of minimizing the self‐weight of frame is simply performed interfacing SAP2000 and MATLAB® software in the form of parallel computing. The meta‐heuristic algorithm chosen here is the cuckoo search (CS) algorithm recently developed as a type of population‐based algorithm inspired by the behavior of some cuckoo species in combination with the Lévy flight behavior. The CS algorithm performs suitable selection of sections from the American Institute of Steel Construction (AISC) wide‐flange (W) shapes list. Strength constraints of the AISC load and resistance factor design specification, geometric limitations, and displacement constraints are imposed on the considered frames. Results show similar weights for optimum designs using spectral and equivalent static analyses; however, different material distribution and seismic behaviors are observed. Copyright © 2014 John Wiley & Sons, Ltd.