Formulation of the Boltzmann Equation as a Multi-Mode Drift-Diffusion Equation

We present a multi-mode drift-diffusion equation as reformulation of the Boltzmann equation in the discrete momentum space. This is shown to be similar to the conventional drift-diffusion equation except that it is a more rigorous solution to the Boltzmann equation because the current and carrier densities are resolved into M x 1 vectors, where M is the number of modes in the discrete momentum space. The mobility and diffusion coefficient become M M matrices which connect the M momentum space modes. This approach is demonstrated by simulating electron transport in bulk silicon

Improvement of Secondary Sedimentation Tanks in the Presence of a Baffle

Source: ICHE Conference Archive - https://mdi-de.baw.de/icheArchiv

A Miniaturized wide Stopband Low-pass Filter using T and Modified L Shapes Resonators

A new structure of microstrip-based low-pass filter with wide stopband and sharp roll-off is introduced, in this paper. In the proposed topology, resonators with T and modified L Shapes have been used. To improve the suppression factor and relative stopband bandwidth, the second resonator has been added to the first resonator. The designed filter has been fabricated on a 20 mm thickness RO4003 substrate, which has a loss tangent of 0.0021 and a relative dielectric constant equal to 3.38. All parameters including roll of rate, stopband, bandwidth, return loss, insertion loss, and figure of merit have significant coefficients. Simulation has been ran using advanced design system software. The 3dB cutoff frequency is appropriate. The value of the insertion loss parameter is <0.1 dB and the S11 parameter is −22 dB at this point. The stopband is extended from 2.42 up to 24 GHz, which shows an ultra-stopband. The results of the simulation and experiment are almost similar, which indicates a proper performance of the designed structure

Effect of Ions on the Organization of Phosphatidylcholine/Phosphatidic Acid Bilayers

AbstractLipid bilayers are two-dimensional fluids. Here, the effect of monovalent ion concentration on the mixing, and consequently the organization, of 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC)/1,2-dioleoyl-sn-glycero-3-phosphate (DOPA) bilayers has been examined. Epifluorescence microscopy was used to visualize the organization. Fluorescence recovery after photobleaching and attenuated total reflection-Fourier transform infrared spectroscopy were used to assess the fluidity of the lipids. At high ionic strength the DOPC and DOPA lipids appear uniformly mixed. Upon lowering the ionic strength, rapid separation is observed. The DOPA-rich regions appear fractal-like and exhibit hysteresis in their properties. The lipids freely exchange between the two regions. These experiments clearly demonstrate the significant effect that electrostatics can have on membrane organization

Ultrastable Synergistic Tetravalent RNA Nanoparticles for Targeting to Cancers

One of the advantages of nanotechnology is the feasibility to construct therapeutic particles carrying multiple therapeutics with defined structure and stoichiometry. The field of RNA nanotechnology is emerging. However, controlled assembly of stable RNA nanoparticles with multiple functionalities which retain their original role is challenging due to refolding after fusion. Herein, we report the construction of thermodynamically stable X-shaped RNA nanoparticles to carry four therapeutic RNA motifs by self-assembly of reengineered small RNA fragments. We proved that each arm of the four helices in the X-motif can harbor one siRNA, ribozyme, or aptamer without affecting the folding of the central pRNA-X core, and each daughter RNA molecule within the nanoparticle folds into their respective authentic structures and retains their biological and structural function independently. Gene silencing effects were progressively enhanced as the number of the siRNA in each pRNA-X nanoparticles gradually increased from one to two, three, and four. More importantly, systemic injection of ligand-containing nanoparticles into the tail-vein of mice revealed that the RNA nanoparticles remained intact and strongly bound to cancers without entering the liver, lung or any other organs or tissues, while remaining in cancer tissue for more than 8 h

Climate change impact on bioclimatic deficiency, using microLEIS DSS in Ahar soils, Iran

Regional impact studies of the future climate change effects are necessary because projected changes in meteorological variables differ from one region to another, and different climate systems can react in varied ways to the same changes. In this study, the effects of climate change on bioclimatic deficiency were compared in two cultivation methods (irrigated and rainfed) in a semi-arid region, Ahar (East Azarbaijan, IRAN). The agricultural land uses selected for evaluation were wheat (Triticum aestivum), alfalfa (Medicago sativa), sugar beet (Beta vulgaris), potato (Solanum tuberosum), and maize (Zea mays). In this way, Terraza model included in the land evaluation decision support system, called MicroLEIS DSS, was used. Terraza gives a quantitative prediction of a site bioclimatic deficiency. Soil morphological and analytical data were obtained from 44 sampling points based on a grid survey. Agro-climatic data, referred to temperature and precipitation, were collected from weather stations located in Ahar region, which benefits from more than 20 consecutive years of weather data. A future scenario of climate change was calculated according to the Intergovernmental Panel on Climate Change (IPCC) on regions of Asia under scenario A1FI (highest future emission) for 2080s. Although, increasing of precipitation being available by climate change in the future scenario, humidity index will be reduced because of high temperature. The results showed that climate change is likely to cause severe water stress in irrigated cultivation of alfalfa, sugar beet, potato, and maize, the use of irrigation methods being essential to maintain agricultural productivity. Although irrigation is indicated as very important in this regime of semi-arid agriculture, cultivation of rainfed wheat can be possible instead of the irrigated one. Also, it is revealed that climate perturbation effects on rainfed conditions are more serious than those on the irrigated conditions in the area.The authors wish to thank Tabriz University for funding this research work, a dissertation of Ph. D. program undertaken by Farzin Shahbazi. They also thank Consejo Superior de Investigaciones Científicas (CSIC), Instituto de Recursos Naturales y Agrobiología de Sevilla (IRNAS), Sevilla, Spain for their sincere cooperation during the candidate’ s sabbatical studies.Peer Reviewe

Synthesis of red mud derived M-type barium hexaferrites with tuneable coercivity

Hexagonal ferrites can be employed in a multitude of applications, the most common hexaferrites are the M ferrites such as BaFe12O19 (barium hexaferrite, BaM). It is known that if Fe3+ is substituted with a combination of Ti4+/Co2+ the coercivity of BaM can be reduced to produce soft M ferrites with easily switchable magnetisation. They can be utilised as powders, films or bulk ceramics, and can be manufactured from a wide variety of synthesis methods. The production of hexaferrites usually requires commercial raw materials, but if an industrial waste can be utilised, this will help to ease waste disposal and storage costs, valorise a waste material and encourage circular economy. In this study, bauxite residue (red mud) from the production of alumina was used to synthesise M-type hexaferrites, using a simple ceramic process. BaCO3, or BaCO3+Co3O4, were added to the red mud, blended and heated at 1000 °C to produce the M-type hexaferrites. Without cobalt addition up to 81.1 wt% M ferrite was produced, and with Co addition up to 74.3 wt% M ferrite was formed. Without cobalt, the M ferrite phase closely resembled BaFe9Al3O19, and was a hard ferrite with a magnetisation of 12–19 A m2/kg for the whole powder (up to 23.6 A m2/kg for the M ferrite phase) and a coercivity of ~290 kA/m. When cobalt was added, secondary titanate phases vanished, and Ti4+/Co2+ partially substituted very soft M ferrite was formed with a low coercivity of ~16 kA/m but a higher magnetisation of 24.5 A m2/kg for the whole powder (up to 34.9 A m2/kg for the M ferrite phase). Therefore, not only can good quality magnetic materials be easily produced from this common waste material, but its magnetic properties can be tuned by varying the 2 + ions added during the process.publishe

Distribution, Severity and Radiologic Features of Intracranial Stenosis in Asymptomatic Pakistanis.

Background: Intracranial atherosclerotic disease (ICAD) is the most common ischemic stroke subtype globally. It accounts for 30–50% of all ischemic strokes in Asians. Aims—The aim of the study is to report the frequency of asymptomatic ICAD and its associated Magnetic Resonance Imaging (MRI) findings. Methods: 200 adult participants were recruited from the Radiology Departments of two major diagnostic centers in Karachi. Eligible participants were confirmed for the absence of stroke symptoms via the Questionnaire for Verifying Stroke Free Status (QVSFS). QVSFS negative subjects underwent MRI on a 1.5 Tesla scanner. Images were centrally reviewed on Di com Viewer 3.0 with electronic calipers to calculate the degree of ICAD. Results: Mean age of subjects was 37.1 years (S.D 15.1) with 50.5% men (n=101) and 49.5% women (n=99). Asymptomatic ICAD was found in 34.5% (n=69) subjects. Of the 3800 intracranial arteries studied, 2.2% (n=88) had biological disease. 20.5% (n=18) of these vessels had atherosclerotic irregularities, 43.2% (n=38) had mild stenos is, 11.4% (n=10) had moderate stenos is, 5.7% (n=5) had severe stenos is while 19.3% (n=17) were completely occluded. The posterior cerebral artery (42% of stenosed arteries, n=37) was most affected. 23.5% (n=47) of subjects had peri-ventricular lucencies, 10.5% (n=21) had brain atrophy while 3.5% (n=7) had silent brain infarcts. There was a significant association between asymptomatic ICAD and peri ventricular lucencies (PR 1.59; 95% CI 1.35–1.99) Conclusion: Asymptomatic ICAD is common in young Pakistanis, with no gender predilection; it preferentially affects the posterior circulation. Silent infarcts are rare compared to peri ventricular lucencies and atrophy