A robust low quiescent current power receiver for inductive power transmission in bio implants

In this paper, a robust low quiescent current complementary metal-oxide semiconductor (CMOS) power receiver for wireless power transmission is presented. This power receiver consists of three main parts including rectifier, switch capacitor DC–DC converter and low-dropout regulator (LDO) without output capacitor. The switch capacitor DC–DC converter has variable conversion ratios and synchronous controller that lets the DC–DC converter to switch among five different conversion ratios to prevent output voltage drop and LDO regulator efficiency reduction. For all ranges of output current (0–10 mA), the voltage regulator is compensated and is stable. Voltage regulator stabilisation does not need the off-chip capacitor. In addition, a novel adaptive biasing frequency compensation method for low dropout voltage regulator is proposed in this paper. This method provides essential minimum current for compensation and reduces the quiescent current more effectively. The power receiver was designed in a 180-nm industrial CMOS technology, and the voltage range of the input is from 0.8 to 2 V, while the voltage range of the output is from 1.2 to 1.75 V, with a maximum load current of 10 mA, the unregulated efficiency of 79.2%, and the regulated efficiency of 64.4%.     

Optimizing blocking flow shop scheduling problem with total completion time criterion

The blocking flow shop scheduling problem has found many applications in manufacturing systems. There are a few exact methods for solving this problem with different criteria. In this paper, efforts will be made to optimize the total completion time criterion for this problem. We present two mixed binary integer programming models, one of which is based on the departure times of jobs from machines, and the other is based on the idle and blocking times of jobs. An initial upper bound generator and some lower bounds and dominance rules are also developed to be used in a branch and bound algorithm. The algorithm solves 17 instances of the Taillard's benchmark problem set in less than 20 min.     

A superabsorbent hydrogel network based on poly((2-dimethylaminoethyl) methacrylate) and sodium alginate obtained by γ-radiation: synthesis and characterization

In this study, the synthesis and characterization of a novel nano-porous superabsorbent hydrogel with high water swelling capacity is described. A nano-porous hydrogel was prepared by employing (2-dimethylaminoethyl) methacrylate (PDMAEMA) as a pH sensitive monomer and sodium alginate (SA) as a water soluble polysaccharide under ??-ray irradiation. The polymerization reaction was performed at room temperature in the absence of chemically toxic crosslinking agent and initiators. The interactive parameters including biopolymer backbone concentration, monomer concentration and ??-irradiation dose were selected as major factors in the synthesis of superabsorbent and three levels for each factor were applied to obtain the highest water swelling according to the central composite design (CCD) method. According to the results of nine different tests which were derived by CCD method, the optimum conditions were determined. The results showed that the hydrogel prepared at concentration of 1.5?g SA, 2.1?mol/L PDMAEMA and at a radiation dose of 5?kGy displayed the highest swelling capacity. In continuation, the effect of salt, pH, and particle size on the swelling behavior of the obtained samples was investigated. We found that the swelling of the optimized sample first increased and then dropped with increases in pH from 2 to 12 and the maximum water absorbency was observed at pH 7. Finally, different techniques such as Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA) and scanning electron microscope (SEM) were applied for the characterization of optimized nano-porous hydrogel.     

Load-balanced Multicast Tree Routing in Multi Channel Multi Radio Wireless Mesh Networks Using a New Cost Function

Wireless Mesh Network (WMN) is new emerging technology that offers low-cost high-bandwidth community wireless services. This type of network requires carefully assignment of resources and load balancing in order to provide the quality guarantees to traffic flows. Load balancing avoids the creation of bottleneck nodes, and increases the network efficiency. This paper addresses the problem of multicast load balancing in Multi-Channel Multi-Radio WMNs (MCMR-WMNs). In this regard, we introduce a novel load-aware dynamic cost function to weight the links of the network. Proposed cost function considers both the benefits of Wireless Broadcast Advantage (WBA) as well as the problem of load balancing. Also, we propose a Load-balanced Multicast Tree Routing (LMTR) algorithm which provides balanced multicast trees using the defined cost function. The proposed on-demand routing scheme not only minimizes the number of transmissions, but also tries to distribute the traffic among the nodes fairly and consequently decreases the interference in the network. We also demonstrate how proposed scheme can control the trade-off between load balancing and delay. Our extensive simulations in various networks with grid and random topologies show the efficiency of LMTR in load balancing. As you will see, LMTR significantly avoids the creation of bottleneck nodes and reduces the standard deviation of traffic load on mesh routers.     

Formation of Al/(Al<Subscript>13</Subscript>Fe<Subscript>4</Subscript> + Al<Subscript>2</Subscript>O<Subscript>3</Subscript>) Nano-composites via Mechanical Alloying and Friction Stir Processing

Combination of mechanical alloying and friction stir processing was used for the fabrication of Al/(Al₁₃Fe₄ + Al₂O₃) nano-composites. Pre-milled hematite + Al powder mixture was introduced into the stir zone generated on 1050 aluminum alloy sheet by friction stir processing. Uniform and active milled powder mixture reacted with plasticized aluminum to produced Al₁₃Fe₄ + Al₂O₃ particles. Al₁₃Fe₄ intermetallic showed elliptical shape with a typical size of ~ 100 nm, while nano-sized Al₂O₃ exhibited irregular floc-shaped particles that formed clusters with the remnant of iron oxide particles in the fine recrystallized aluminum matrix. As the milling time (1-3 h) of the introduced powder mixture increased, the volume fraction of Al₁₃Fe₄ + Al₂O₃ particles increased in the fabricated composite. The hardness and ultimate tensile strength of the fabricated nano-composites varied from 54.5 to 75 HV and 139 to 159 MPa, respectively; these are much higher than those of the friction stir processed base alloy (33 HV and 97 UTS). The highest hardness and strength were achieved for the nano-composite fabricated using the 3-h milled powder mixture; hard nano-sized reaction products and fine recrystallized grains of Al matrix had major and minor roles on enhancing these properties, respectively.     

Different TiO2 nanotubes for back illuminated dye sensitized solar cell: fabrication,characterization and electrochemical impedance properties of DSSCs

In the present work we reported the fabrication of different TiO₂ nanotube arrays (TiO₂ NTs) by anodization method. When used in dye-sensitized solar cells, the TiO₂ NTs prepared in the two-step anodization process (2-step TiO₂ NTs) showed better efficiency than those of TiO₂ NTs prepared in one step anodization process (1-step TiO₂ NTs). The 2-step TiO₂ NTs show a remarkable efficiency of 1.56 %. This is higher than those of TiO₂ NTs prepared in one step anodization process. Electrochemical impedance spectroscopy has been performed for qualitative analysis of charge transport process in dye-sensitized solar cells.     

Ultrasonically accelerated synthesis of silver nanocomposite hydrogel based on salep biopolymer: application in Rhodamine dye adsorption

Silver nanocomposite hydrogel (SNH) based on poly(acrylic acid) grafted onto salep was prepared without initiator and under just 2 min ultrasonic irradiation for the first time. The SNH was then applied as an adsorbent for Rhodamine removal from aqueous solution. The SNH adsorbent was characterized by Fourier transform infrared (FTIR) spectroscopy, thermogravimetric analysis, scanning electron microscopy, transmission electron microscopy images and X-ray photoelectron spectroscopy. A 2⁴ full factorial central composite design, a linear mathematical model representing the influence of different variables and their interactions, was successfully employed for experimental design and analysis of the results. Analysis of variance demonstrated that Rhodamine adsorption significantly increased with increases in the amount of adsorbent, extraction time, stirring rate of the solution and Rhodamine volume as donor phase volume, but slightly decreased with an increase in temperature and pH of Rhodamine solution. The adsorption behaviors showed that the adsorption kinetics were in good agreement with a pseudo-second-order model for Rhodamine removal from aqueous solution. Thermodynamic studies revealed the feasibility and exothermic nature of the system. Adsorption mechanism was studied through two important adsorption isotherm models (Langmuir and Freundlich models). Under the optimal experimental conditions, the detection limit was found to be 0.94 µg mL^?1 for Rhodamine adsorption. The limit of quantification and the linear range of calibration curve were 3.14 µg mL^?1 and 1.00–10.98 µg mL^?1, respectively.     

Influence of ionic surfactant on physio-electrochemical properties and fractal dimension of poly ortho aminophenol film

We describe in detail the advantages of a novel method of electrochemical preparation of poly ortho aminophenol (POAP), based on the ability of anionic surfactants to form micelles in aqueous media. We demonstrate that the electropolymerisation process carried out in the presence of Sodium Dodecyl Sulfate (SDS) at an oxidation potential lower than in an aqueous media yields better organized POAP films. The improved physicochemical and structural properties of POAP obtained in these conditions can be related to the electrocatalytic effect of SDS and change fractal dimension of film. With respect to Ni–POAP/G, Ni–SDS–POAP/G electrode shows a higher catalytic performance for the electrocatalytic oxidation of saccharose.     

Recent Advances of Functional Proteomics in Gastrointestinal Cancers- a Path towards the Identification of Candidate Diagnostic,Prognostic, and Therapeutic Molecular Biomarkers

Gastrointestinal (GI) cancer remains one of the common causes of morbidity and mortality. A high number of cases are diagnosed at an advanced stage, leading to a poor survival rate. This is primarily attributed to the lack of reliable diagnostic biomarkers and limited treatment options. Therefore, more sensitive, specific biomarkers and curative treatments are desirable. Functional proteomics as a research area in the proteomic field aims to elucidate the biological function of unknown proteins and unravel the cellular mechanisms at the molecular level. Phosphoproteomic and glycoproteomic studies have emerged as two efficient functional proteomics approaches used to identify diagnostic biomarkers, therapeutic targets, the molecular basis of disease and mechanisms underlying drug resistance in GI cancers. In this review, we present an overview on how functional proteomics may contribute to the understanding of GI cancers, namely colorectal, gastric, hepatocellular carcinoma and pancreatic cancers. Moreover, we have summarized recent methodological developments in phosphoproteomics and glycoproteomics for GI cancer studies.