This paper proposes a 2.4 GHz active mixer without passive inductor for the transceiver system. Taking into account the design requirements of the mixer, a double-balanced down-conversion structure with active inductor and negative resistance is designed. The proposed mixer with 130 nm CMOS technology is designed and simulated using Cadence software at 1.5 V supply voltage. Although we had to compromise conversion gain with linearity, we were able to achieve very high conversion gain with average linearity. Based on the results of post-layout simulations, the conversion gain of 27.57 dB, IIP3 equal to -7.88 dBm, 1-dB compression point equal to -17.34 dBm and IIP2 equal to 44.22 dBm with power consumption of 2.5 mW was obtained for the proposed mixer. The chip size without input and output pads is 95.18 µm × 117.68 µm, which leads to a chip area of 0.0112mm2.

What is RNA Extraction?RNA extraction is the purification of RNA from biological samples. This procedure is complicated by the ubiquitous presence of ribonuclease enzymes in cells and tissues, which can rapidly degrade RNA. Several methods are used in molecular biology to isolate RNA from difficult samples. Here CTAB modified method is described.

A power divider (PD)/ power combiner (PC) with high quality factor and enhanced output ports isolation using substrate integrated waveguide (SIW) technology is proposed. An SIW cavity is designed to provide a high quality factor filtering response and an SMD resistor is attached between two output ports to realize the high isolation. The value of the applied resistor is calculated by using the even and odd mode analysis. The measured results obtained from testable model are in good agreement with the simulated results. These results show that the return loss is 23 dB, the minimum insertion loss is 4. 55 dB including intrinsic 3 dB insertion loss of PD, and the isolation between output ports is 20 dB, which shows that the proposed design could be an important component in microwave circuits.

The proposed research presents a two-port compact Multiple Input Multiple Output (MIMO) antenna for Ultra-Wide Band (UWB) applications. The designed antenna has two identical radiators and has an overall dimension of 20 × 44.1 × 1.6mm3 on a FR4 substrate. The designed antenna is fed by a 50-microstrip line. Extended F-shaped stubs are introduced in the shared ground plane of the proposed antenna to produce high isolation between the MIMO antenna elements. Extended F-shaped stubs are introduced in the ground plane to produce multiple resonance and high isolation between the radiating elements. The antenna offers good impedance matching in the UWB band. The proposed antenna has lower isolation < -25 dB and Envelope Correlation Coefficient (ECC) < 0.015 from 3.1 to 10.6 GHz. Antenna parameters are evaluated in term of return loss, ECC, Diversity Gain (DG), gain, Total active reflection coefficient (TRAC) radiation pattern and isolation. The proposed antenna is tested and fabricated. However, obtained results are good agreement which make suitable for UWB wearable applications.

Social isolation is one prevalent social deficiencies among adolescents. Reasons of social isolation in adolescents are not clear yet. One of the variables that have attracted researchers in recent years to the etiology of social isolation is the dependence on new communication technologies, especially the Internet. This study aimed to determine the relationship between cyberspace dependency and social isolation in adolescents. This study conducted with a survey and cross-sectional design. Statistical population was high school students in Yazd. 535 (218 male and 317 female) adolescents selected using proportional stratified sampling. Instruments of data gathering are: Internet Addiction Test (IAT); and The UCLA Loneliness Scale-version 3 (UCLALS-v3). Cyberspace dependency prevalence rate in this research was 21. 7%. Significant difference were found between normal and dependent to cyberspace users, regarding the general social isolation (P <. 01); and components of isolation (P <. 01); relational association (P <. 01); and collective association (P <. 05). Hierarchical multiple linear regression analysis showed that cyberspace dependency, explained for 12. 2% of the variance of social isolation. Cyberspace dependency is a main risk factor for adolescent's social isolation and increases the risk of social isolation among adolescents. According to this result, preventive behavioral and cognitive interventions are necessary in order to change the internet use pattern and reducing the social isolation among adolescents.