Differences in the Activity of Endogenous Bone Morphogenetic Protein Signaling Impact on the Ability of Induced Pluripotent Stem Cells to Differentiate to Corneal Epithelial-Like Cells

Cornea is a clear outermost layer of the eye which enables transmission of light onto the retina. The transparent corneal epithelium is regenerated by limbal stem cells (LSCs), whose loss/dysfunction results in LSCs deficiency (LSCD). Ex vivo expansion of autologous LSCs obtained from patient's healthy eye followed by transplantation onto the LSCs damaged/deficient eye, has provided a successful treatment for unilateral LSCD. However, this is not applicable to patient with total bilateral LSCD, where LSCs are lost/damaged from both eyes. We investigated the potential of human induced pluripotent stem cell (hiPSC) to differentiate into corneal epithelial-like cells as a source of autologous stem cell treatment for patients with total bilateral LSCD. Our study showed that combined addition of bone morphogenetic protein 4 (BMP4), all trans-retinoic acid and epidermal growth factor for the first 9 days of differentiation followed by cell-replating on collagen-IV-coated surfaces with a corneal-specific-epithelial cell media for an additional 11 days, resulted in step wise differentiation of human embryonic stem cells (hESC) to corneal epithelial progenitors and mature corneal epithelial-like cells. We observed differences in the ability of hiPSC lines to undergo differentiation to corneal epithelial-like cells which were dependent on the level of endogenous BMP signaling and could be restored via the activation of this signaling pathway by a specific transforming growth factor β inhibitor (SB431542). Together our data reveal a differential ability of hiPSC lines to generate corneal epithelial cells which is underlined by the activity of endogenous BMP signaling pathway

Planar monopole antenna for WBAN

This paper presents circular-shape monopole antenna for wireless body area net-work (WBAN) applications at 3.1 to 5.1 GHz and 6.5 to 8 GHz. The design and simulation of proposed antenna for WBAN applications in the free space and close proximity of body surface has been done by using CST Microwave Studio. The proposed antenna was designed on FR4 substrate with dielectric constant (εr) of 4.4 and thickness of 1.6 mm. The final optimized design is 50 × 40mm2. The simulated current distribution on the radiating patch for the proposed circular-shaped monopole antenna frequencies of 3.3 and 7.5 GHz in the free space is presented. The size of circular-shape monopole antenna it is suitable for WBAN application

Design of Phased Arrays of Series-Fed Patch Antennas With Reduced Number of the Controllers for 28-GHz mm-Wave Applications

New modified 2 × 2 and 3 × 3 series-fed patch antenna arrays with beam-steering capability are designed and fabricated for 28-GHz millimeter-wave applications. In the designs, the patches are connected to each other continuously and in symmetric 2-D format using the high-impedance microstrip lines. In the first design, 3-D beam-scanning range of ± 25° and good radiation and impedance characteristics were attained by using only one phase shifter. In the second one, a new mechanism is introduced to reduce the number of the feed ports and the related phase shifters (from default number 2 N to the reduced number N + 1 in the serial feed (here N = 3) and then the cost, complexity, and size of the design. Here, good scanning performance of a range of ± 20°, acceptable sidelobe level, and gain of 15.6 dB are obtained. These features allow to use additional integrated circuits to improve the gain and performance. A comparison to the conventional array without modification is done. The measured and simulated results and discussions are presented

Radiation characteristics improvement of monopole antenna above glass substrate for WBAN applications

A P-shaped monopole antenna (PSMA) attached with a glass substrate is proposed for wireless body area networks (WBAN) applications. The study investigates the performance of PSMA above reflection plane substrates with different material of glass and a perfect electric conductor (PEC). The PSMA prototype is fabricated on the FR4 substrateto be operated between 3.1 to 5.1 GHz frequency band. It is discovered that the PSMA efficiency could be enhanced by integrating the ground plane with a glass for the brain and chest human body. For brain model, the antenna efficiency of 78.8%, 80.3% and 85.6% is achieved for 3.3, 4.45 and 5 GHz respectively. The antenna efficiency in the chest model is improved to 75.2%, 76.35% and 81.2% at particular 3.3, 4.45 and 5 GHz respectively. Therefore, this study concludes that the reflection plane help to increase the gain and efficiency of close proximity of body surface. Additionally, the PSMA with reflection plane improves SAR when placed near human body if compared to the other antennas. A fascinating conformity was found between the simulation and measurement results that potentialto be deployed for WBAN applications

MIMO dielectric resonator antenna for LTE femtocell access point applications

© 2015 EurAAP.A four-port MIMO dielectric resonator antenna (DRA) is studied and proposed. The antenna consisting of four rectangular dielectric resonator (RDR) elements, each one is fed by a coplanar feed line, is fabricated on FR4 substrate. A parametric study is carried out and the presented antenna has been fabricated. The presented MIMO DRA having good MIMO characteristics offers a measured bandwidth of 250 MHz between 2480 MHz and 2730MHz for S11 < -10dB, which can operate on LTE bands 7 (2500-2570MHz) and 38 (2570-2620MHz). In these frequency bands the measured isolation is less than -17dB. By calculating and measuring the envelop correlation coefficient, mean effective gains and the diversity gain, the MIMO performance of the presented antenna has been examined. The antenna presented is easy to feed, fabricate, and can be a good candidate for LTE femtocell access point applications

Triple-band CPW-FED planar monopole antenna for WLAN/WiMax application

A triple-band planar monopole antenna is presented in this article. The antenna consists of three strips which correspond to operating frequency bands of 2.4, 3.5, and 5.8 GHz. The proposed antenna has been designed, simulated, and fabricated on 20 × 38 mm2 FR4 board. There is good agreement between simulation and measurement results in terms of return loss and radiation pattern. The proposed antenna provides measured -10 dB bandwidths of 200 MHz for the 2.4 GHz (from 2.36 to 2.56 GHz); 620 MHz for the 3.5 GHz (from 3.48 to 4.10 GHz); and 1.38 GHz for 5.8 GHz (from 5.65 to 7.03 GHz). Moreover, the antenna provides the measured gain of 4.73, 1.66, and 3.28 dBi for 2.4, 3.5, and 5.8 GHz, respectively. The radiation characteristics have proven that the proposed antenna seems to be a good potential candidate for WLAN/WiMAX applications. © 2013 Wiley Periodicals, Inc

Path loss model and root mean square delay spread characterization of near-ground outdoor UWB channel

© 2015 EurAAP.The large bandwidth of ultra wideband (UWB) makes it attractive in high speed transmission applications. However, the possibility of frequency selectivity of the channel is high due to this bandwidth. Channel characterization is important to study the behavior of the channel. The ground reflection effects are important parameters affecting the ultra wideband channel. In this paper, based on outdoor time domain measurements, path loss model and root mean square (RMS) delay spread characteristics for near-ground (NG) UWB channel have been presented. Moreover, the interdependencies of these characteristics of the multipath channel are also investigated. The NG UWB channel characteristics are compared to the UWB channel above the ground. From the results it has been found that the path loss in NG UWB channel is less as compared to the above ground case. Also, the values of RMS delay spread are low

Radiation characteristics improvement of monopole antenna for WBAN applications

The design, simulation and fabrication of a P-shaped monopole antenna for wireless body area networks (WBAN) applications is presented in this paper. It is noted that the radiation characteristics was improved by attaching a P-shaped element to the ground plane. The simulation of the proposed antenna in the free space and close proximity of body surface has been done using CST Microwave Studio. The proposed antenna is designed on the FR4 substrate with dielectric constant of 4.4 and 1.6mm thickness; and the operating frequency band is between 3.1 to 5.1GHz. The final optimized design has dimensions of 32mm ×28mm. The proposed antenna improves the gain of close proximity of body surface. In addition, the antenna improves the reflection coefficient when placed close human body compared to other antennas. It was observed that there is good agreement between the simulation and measurement results, thereby showing that the antenna is potential to be deployed for WBAN application. © 2014 SERSC