Temperature/pH/magnetic triple‐sensitive nanogel–hydrogel nanocomposite for release of anticancer drug

Hydrogels, nanogels and nanocomposites show increasing potential for application in drug delivery systems due to their good chemical and physical properties. Therefore, we were encouraged to combine them to produce a new compound with unique properties for a long‐term drug release system. In this regard, the design and application of a nanocomposite hydrogel containing entrapped nanogel for drug delivery are demonstrated. To this aim, we first prepared an iron oxide nanocomposite nanogel based on poly(N‐isopropylacrylamide)‐co‐((2‐dimethylaminoethyl) methacrylate) (PNIPAM‐co‐PDMA) grafted onto sodium alginate (NaAlg) as a biocompatible polymer and iron oxide nanoparticles (ION) as nanometric base (PND/ION‐NG). This was then added into a solution of PDMA grafted onto NaAlg. Through dropwise addition of mixed aqueous solution of iron salts into the prepared polymeric solution, a novel hydrogel nanocomposite with excellent pH, thermal and magnetic responsivity was fabricated. The synthesized samples were fully characterized using Fourier transform infrared spectroscopy, thermogravimetric analysis, scanning electron microscopy with energy‐dispersive X‐ray analysis, vibrating sample magnetometry and atomic force microscopy. A mechanism for the formation of PNIPAM‐co‐PDMA/NaAlg‐ION nanogel–PDMA/NaAlg‐ION hydrogel and PND/ION nanogel is suggested. Swelling capacity was measured at various temperatures (25 to 45 °C), pH values (from 2 to 11) and magnetic field and under load (0.3 psi) and the dependence of swelling properties of the nanogel–hydrogel nanocomposite on these factors was well demonstrated. The release rate of doxorubicin hydrochloride (DOX) as an anticancer drug was studied at different pH values and temperatures in the presence and absence of a magnetic field. The results showed that these factors have a high impact on drug release from this nanocomposite. The result showed that DOX release could be sustained for up to 12.5 days from these nanocomposite hydrogels, significantly longer than that achievable using the constituent hydrogel or nanogel alone (<1 day). The results indicated that the nanogel–hydrogel nanocomposite can serve as a novel nanocarrier for anticancer drug delivery. © 2019 Society of Chemical Industry     

Characterization of the Ion Beam Current Density of the RF Ion Source with Flat and Convex Extraction Systems

Silicon - The characterization of ion beam current density distribution and beam uniformity is crucial for improving broad-beam ion source technologies. The design of the broad ion beam extraction...     

Optimized partitioning of a wavelength distributed data interfacering network

A fiber optic ring network, such as fiber distributed data interface (FDDI), can be operated over multiple wavelengths on its existing fiber plant consisting of point-to-point fiber links. Using wavelength division multiplexing (WDM) technology, FDDI nodes can be partitioned to operate over multiple subnetworks, with each subnetwork operating independently on a different wavelength, and inter-subnetwork traffic forwarding performed by a bridge. For this multiwavelength version of FDDI, which we refer to as wavelength distributed data interface (WDDI), we examine the necessary upgrades to the architecture of a FDDI node, including its possibility to serve as a bridge. The main motivation behind this study is that, as network traffic scales beyond (the single-wavelength) FDDI's information-carrying capacity, its multiwavelength version, WDDI, can gracefully accommodate such traffic growth. A number of design choices exist in constructing a good WDDI network. Specifically, we investigate algorithms using which, based on prevailing traffic conditions, partitioning of nodes into subnetworks can be performed in an optimized fashion. Our algorithms partition the nodes into subrings, such that the total traffic flow in the network and/or the network-wide average packet delay is minimized     

Novel amplified fiber-optic recirculating delay line processor

The application of optical amplifiers (OAs) to fiber-optic delay line signal processing is demonstrated. Both erbium-doped fiber amplifiers (EDFAs) and semiconductor optical amplifiers (SOAs) are applicable. Analytical results are presented for both amplified and unamplified fiber-optic recirculating delay lines (AFORDLs and UFORDLs). In the AFORDL an OA is inserted in the fiber loop. It is shown that the active AFORDL structure is capable of realizing all-fiber filters not possible with the passive UFORDL. This result is significant because it shows that the OAs can function beyond just the trivial optical loss compensation to provide extra flexibility not available in passive designs. An AFORDL design is presented which has a pole near +1 and a zero at -1 in the Z-plane resulting in useful characteristics in the magnitude and phase responses. The results suggest that extension of the concept to higher-order filters has the potential to lead to the realization of more complex optical processors     

Process uniformity and slip dislocation patterns in linearlyramped-temperature transient rapid thermal processing of silicon

Rapid thermal processing (RTP) of silicon using transient linearly ramped-temperature saw-toothed and triangular thermal cycles has been evaluated by characterization of the process uniformity and slip dislocation line patterns for a wide range of process parameters. Rapid thermal oxidation was chosen as the process vehicle for these studies. The process uniformity and slip dislocation line patterns are strongly affected by both the transient and steady-state segments of the thermal cycles. The strong dependencies of the process uniformity and slip dislocation lines on the thermal cycle parameters suggest that the overall performance of a RTP reactor must be specified not only under steady-state thermal conditions, but also for controlled transient thermal cycles. Transient ramped-temperature RTP cycles with medium-to-high peak process temperatures (i.e. T_max=1100°-1150°C) were found to be the optimal process conditions for growing thin gate oxides in the range of 60-120 Å with superior process uniformity and minimum slip dislocation line generation. The results of this work provide insight and useful methodology for process optimization in order to improve process uniformity, minimize generation of slip dislocation lines, and obtain good device electrical characteristics     

Multi expression programming: a new approach to formulation of soil classification

This paper presents an alternative approach to formulation of soil classification by means of a promising variant of genetic programming (GP), namely multi expression programming (MEP). Properties of soil, namely plastic limit, liquid limit, color of soil, percentages of gravel, sand, and fine-grained particles are used as input variables to predict the classification of soils. The models are developed using a reliable database obtained from the previously published literature. The results demonstrate that the MEP-based formulas are able to predict the target values to high degree of accuracy. The MEP-based formulation results are found to be more accurate compared with numerical and analytical results obtained by other researchers.     

Adaptive Control for State Synchronization of Nonlinear Haptic Telerobotic Systems with Asymmetric Varying Time Delays

In this paper, we introduce a new adaptive controller design scheme for nonlinear telerobotic systems with varying time delays where the delays and their variation rates are unknown. The designed controller has the ability to synchronize the state behaviors of the local and the remote robots. In this paper, asymptotic stability in the presence of varying time delays is of interest. Using the proposed controller, asymptotic stability of the bilateral telerobotic system subject to any bounded yet unknown varying delay with a bounded yet unknown rate of change can be guaranteed. Besides the varying time delay, the proposed adaptive controller has the ability to adapt to the parameter variations in the local and the remote robots’ dynamics. It is shown that position and velocity errors between the local and the remote manipulators converge to the zero asymptotically, thus ensuring teleoperation transparency. Experimental and simulation results with a pair of PHANToM haptic devices and a pair of planar manipulators under varying time delays in the communication channel demonstrate the effectiveness of the proposed scheme.     

Estimating the scattering distribution of the received signals in multipath fading channels

This paper presents a novel approach for estimating the distribution of the incoming waves at the mobile unit antenna, i.e. the scattering distribution, in a typical micro-cellular system. This estimate is vital in determining many system parameters of interest as well as designing unbiased estimators for the velocity of mobile units in micro-cellular systems. The proposed approach deploys the zero-crossing rates of the quadrature components and the instantaneous frequency of the received signal at the mobile unit to estimate the scattering distribution. We also propose a new model for simulating multipath fading channels with non-isotropic scattering. We use the channel simulator to evaluate the performance of the proposed estimator for the scattering distribution. Simulation results show that proposed estimator exhibits small bias and root mean square error.     

Rapid Synthesis of Cobalt Metal Organic Framework

Metal-organic framework (MOF) has been shown to potential applications due to the high porous hybrid structure. Cobalt MOF was synthesized rapidly by ultrasound energy with about 3,000 m²/g surface area by BET method. Furthermore, this component is crystalline with significant thermal stability, on account of X-ray diffraction and thermal analysis, respectively. Based on high roughness, crystallinity, and unreported type of FTIR spectrum, a new structure of Co-MOF structure was proposed.