Design of hexa‐band planar inverted‐F antenna using hybrid BSO‐NM algorithm for mobile phone communications

This article presents a new design of multiband planar inverted‐F antenna with slotted ground plane and S‐etched slot on the radiation patch. The proposed antenna is optimized using an efficient global hybrid optimization method combining bacterial swarm optimization and Nelder‐Mead (BSO‐NM) algorithm to cover a very important six service bands including GSM900, GPS1575, DCS1800, PCS1900, ISM2450, and 4G5000 MHz with enhanced bandwidths. The BSO‐NM algorithm in Matlab code is linked to the CST Microwave studio software to simulate the antenna. To validate the results, the antenna is analyzed using the finite difference time domain (FDTD) method. A good agreement is achieved between the results of EM simulation and that produced from the FDTD method. © 2012 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2013.     

Congestion detection technique for multipath routing and load balancing in WSN

In WSN, nodes collect the information from the surrounding environment and transferring to base station. Multiple data transmission in a WSN causes the nodes near the base station to get congested. Here we propose to develop a congestion avoidance and mitigation technique. For that, we select routes based on the distance between sender and receiver, relative success rate (RSR) value of node and buffer occupancy of a node. Based on these three parameters, we define a utility function to be applied to each neighbor of a transmitter node. Hence the transmitter node chooses the highest U-valued node as its next hop node among its neighbors in packet forwarding. Thus we avoid congestion by choosing non-congested nodes as its next hop node and then we mitigate congestion based on RSR values.     

Ultratrace and isotope analysis of long-lived radionuclides by inductively coupled plasma quadrupole mass spectrometry using a direct injection high efficiency nebulizer

The direct injection high efficiency nebulizer (DIHEN) was explored for the ultrasensitive determination of long-lived radionuclides ((226)Ra, (230)Th, (237)Np, (238)U, (239)Pu, and (241)Am) and for precise isotope analysis by inductively coupled plasma mass spectrometry (ICPMS). The DIHEN was used at low solution uptake rates (1-100 μL/min) without a spray chamber. Optimal sensitivity (e.g., (238)U, 230 MHz/ppm; (230)Th, 190 MHz/ppm; and (239)Pu, 184 MHz/ppm) was achieved at low nebulizer gas flow rates (0.16 L/min), high rf power (1450 W), and low solution uptake rates (100 μL/min). The optimum parameters varied slightly for the two DIHENs tested. The detection limits of long-lived radionuclides in aqueous solutions varied from 0.012 to 0.11 ng/L. The sensitivity of the DIHEN was improved by a factor of 3 to 5 compared with that of a microconcentric nebulizer (MicroMist used with a minicyclonic spray chamber at a solution uptake rate of 85 μL/min) and a factor of 1.5 to 4 compared with that of a conventional nebulizer (cross-flow used with a Scott type spray chamber at a solution uptake rate of 1 mL/min). The precision of the DIHEN ranged from 0.5 to 1.7% RSD (N = 3) for all measurements at the 10 ng/L concentration level (～3 pg sample size). The sensitivity decreased to 10 MHz/ppm at a solution uptake rate of 1 μL/min. The precision was about 5% RSD at a sample size of 30 fg for each long-lived radionuclide by the DIHEN-ICPMS method. The oxide to atom ratios were less than 0.05 (except ThO(+)/Th(+) ) and decreased under the optimum conditions in the following sequence: ThO(+)/Th(+) > UO(+)/U(+) > NpO(+)/Np(+) > PuO(+)/Pu(+) > AmO(+)/Am(+) > RaO(+)/Ra(+). Atomic and oxide ions were used as analyte ions for ultratrace and isotope analyses of long-lived radionuclides in environmental and radioactive waste samples. The analytical methods developed were applied to the determination of long-lived radionuclides and isotope ratio measurements in different radioactive waste and environmental samples using the DIHEN in combination with quadrupole ICPMS. For instance, the (240)Pu/(239)Pu isotope ratio was measured in a radioactive waste sample at a plutonium concentration of 12 ng/L. This demonstrates a main advantage of DIHEN-ICPMS compared with α-spectrometry, which cannot be used to selectively determine (239)Pu and (240)Pu because of similar α energies (5.244 and 5.255 MeV, respectively).     

Synthesis and Sintering of Large Batches of Barium Zirconate Nanopowders

The acrylamide gelification process is a fast, inexpensive, reproducible, and easily scaled up chemical method for obtaining nanopowders of BaZrO₃ that can be used for sintering crucibles and many electronic applications. This method enables the production of 100 g of high-purity powders in one run, using simple laboratory equipment and low-cost raw materials. The gelification process, synthesis temperature, and gas conditions required for obtaining high-quality powders were the subjects of the present study. Fine powders were sintered to full density at 1450°C, making the fabrication of BaZrO₃ crucibles possible for many laboratories.     

Chemical reaction interface mass spectrometry with high efficiency nebulization

A high efficiency nebulizer (HEN) coupled to a heated spray chamber and a membrane desolvator is used for liquid sample introduction in chemical reaction interface mass spectrometry (CRIMS). Compared to the conventional thermospray nebulizer operated at solvent flow rate of 1 mL/min, the HEN provides small droplets at lower flow rates (10-100 microL/min), improving the desolvation and analyte transport efficiency. As a result, the sensitivity for carbon detection by CRIMS is improved by a factor of 4. The new arrangement offers an easy-to-use and robust interface, facilitating the availability of a variety of liquid chromatographic techniques to the CRIMS. Separation and detection of labeled peptides in a mixture of unlabeled biopolymers is illustrated at a solvent flow rate of 45 microL/min as an example of new possibilities offered by the improved liquid introduction interface.     

Ganciclovir and Its Hemocompatible More Lipophilic Derivative Can Enhance the Apoptotic Effects of Methotrexate by Inhibiting Breast Cancer Resistance Protein (BCRP)

Efflux transporters, namely ATP-binding cassette (ABC), are one of the primary reasons for cancer chemoresistance and the clinical failure of chemotherapy. Ganciclovir (GCV) is an antiviral agent used in herpes simplex virus thymidine kinase (HSV-TK) gene therapy. In this therapy, HSV-TK gene is delivered together with GCV into cancer cells to activate the phosphorylation process of GCV to active GCV-triphosphate, a DNA polymerase inhibitor. However, GCV interacts with efflux transporters that are responsible for the resistance of HSV-TK/GCV therapy. In the present study, it was explored whether GCV and its more lipophilic derivative (1) could inhibit effluxing of another chemotherapeutic, methotrexate (MTX), out of the human breast cancer cells. Firstly, it was found that the combination of GCV and MTX was more hemocompatible than the corresponding combination with compound 1. Secondly, both GCV and compound 1 enhanced the cellular accumulation of MTX in MCF-7 cells, the MTX exposure being 13–21 times greater compared to the MTX uptake alone. Subsequently, this also reduced the number of viable cells (41–56%) and increased the number of late apoptotic cells (46–55%). Moreover, both GCV and compound 1 were found to interact with breast cancer resistant protein (BCRP) more effectively than multidrug-resistant proteins (MRPs) in these cells. Since the expression of BCRP was higher in MCF-7 cells than in MDA-MB-231 cells, and the cellular uptake of GCV and compound 1 was smaller but increased in the presence of BCRP-selective inhibitor (Fumitremorgin C) in MCF-7 cells, we concluded that the improved apoptotic effects of higher MTX exposure were raised mainly from the inhibition of BCRP-mediated efflux of MTX. However, the effects of GCV and its derivatives on MTX metabolism and the quantitative expression of MTX metabolizing enzymes in various cancer cells need to be studied more thoroughly in the future.     

A Versatile,Digital Sequencer for Programmed Electrical Heating of Nonflame Atomizers

ABSTRACT

A simple, inexpensive, yet flexible digital sequencer is described for the programming of electrically heated nonflame atomizers. The system provides four distinct periods of operation and a three step analog output for controlling the atomizer heating during desolvation, ashing and atomization. The sequencer is sufficiently versatile to allow it to be used with any nonflame atomizer with only minor modifications. Performance tests of the sequencer with the graphite braid nonflame atomizer are presented and illustrate that results comparable to those obtained with a laboratory minicomputer can be readily achieved.     

Design of multiband PIFA with low SAR value for all commercial mobile communication bands

A low profile planar inverted‐F antenna is proposed for mobile handset applications. Thus, our target is to introduce a new antenna that supports both services, the proposed antenna have broadband characteristic which includes all commercial service bands, GSM850/GSM900/GPS/GSM1800/GSM1900/WCDMA2100/802.11b/g/LTE2600 (824–2690 MHz) as well as 802.11a/n (5150–5825 MHz). Overall size of the antenna is 21 × 45 × 8 mm³ is well suited for mobile handsets due to its low profile, small size, wide bandwidth, the radiation patterns are satisfactorily omnidirectional across the antenna's operation bands, and good gain (the gain in some frequency bands is higher than 4 dBi). The antenna not only has a compact size, but also it supports a low specific absorption rate (SAR) radiation at all the operating frequencies. In addition, the proposed antenna is assessed using the finite difference time domain (FDTD) program written with MATLAB to validate the results. The antenna meets three challenging parameters: the compact size, the multiband operation including the low frequency bands, and the low SAR radiation. The measured results exhibit good agreement with the simulation results from CST and the FDTD program written with MATLAB. As a result, the designed antenna is suitable for small mobile devices and slim wireless applications. © 2014 Wiley Periodicals, Inc. Int J RF and Microwave CAE 25:194–201, 2015.     

In situ visualization and characterization of aerosol droplets in an inductively coupled plasma

Laser-scattering techniques are utilized for the first time to visualize the aerosol droplets in an inductively coupled plasma (ICP) torch from the nebulizer tip to the site of analytical measurements. The resulting images provide key information about the spatial distribution of the aerosol introduced by direct injection and conventional sample introduction devices: (1) a direct injection high-efficiency nebulizer (DIHEN); (2) a large-bore DIHEN; and (3) a MicroFlow PFA nebulizer with a PFA Scott-type spray chamber. Moreover, particle image velocimetry is used to study the in situ behavior of the aerosol before interaction with the plasma, while the individual surviving droplets are explored by particle tracking velocimetry. Directly introduced aerosols are highly scattered across the plasma torch as a result of their radial motion, indicating less than optimum sample consumption efficiency for the current direct injection devices. Further, the velocity distribution of the surviving droplets demonstrates the importance of the initial droplet velocities in complete desolvation of the aerosol for optimum analytical performance in ICP spectrometries. These new observations are critical in the design of the next-generation direct injection devices for lower sample consumption, higher sensitivity, lower noise levels, suppressed matrix effects, and developing smart spectrometers.     

A direct injection high-efficiency nebulizer for inductively coupled plasma mass spectrometry

A simple, relatively low-cost direct injection high-efficiency nebulizer (DIHEN) is introduced for argon inductively coupled plasma (Ar ICP) spectrometry. The DIHEN may be operated at solution uptake rates of 1-100 microL/min. Analytical performance indexes for the DIHEN and fundamental characteristics of the aerosol produced are obtained using an ICP mass spectrometer (ICPMS) and a two-dimensional phase Doppler particle analyzer (2D PDPA), respectively. Results are compared to those obtained with a conventional crossflow pneumatic nebulizer (PN), equipped with a Scott-type spray chamber. Droplet sizes and velocities produced with the DIHEN are smaller than those reported for the direct injection nebulizer (DIN). The DIHEN offers optimal sensitivity at low injector gas flow rates (approximately 0.25 L/min) and high rf power (approximately 1.5 kW). For the 17 elements tested, detection limits (ppt) and sensitivities achieved with the DIHEN (at 85 microL/min) are similar to, or better than, those obtained on the same instrument using the PN (at 1 mL/min). However, because the primary aerosol is injected directly into the plasma, oxide-to-metal ion ratios (MO+/M+) are high, as in the case of the DIN. The utility of the DIHEN for the analysis of small-volume samples is demonstrated by microscale flow injection analysis (muFIA) of Cr bound to human lung DNA. Detection of Cr at the femtogram level is feasible.