reza talebzadeh

In this research work, a plasmonic sensor based on metamaterial has been designed to measure the refractive index of materials. In this structure, a diagnostic resonator medium with rectangular receivers with different dimensions is used alternately and regularly in a ring to trap more of the field at the top and bottom of the metal-insulator-metal layered structure. The structure supports a resonant mode that leads to a sharp peak in the absorption spectrum, resulting in a sensor with a figure of merit of at a resonant wavelength of 8.35 GHz. All the steps of simulation and optimization of the proposed sensor have been done using commercial software CST Microwave studio and the effect of different parameters of changes in structure dimensions and changes in refractive indices on the absorption spectrum has been investigated. The proposed plasmonic sensor can be used to measure the refractive index and medical diagnosis with an extraordinary level of sensitivity equal to 6400 (μm/RIU) and very high-quality index (283.7). This structure has a high degree of protection against manufacturing errors in the dimensions of the receivers as well as the corrosion of the diagnostic environment and for that reason, it is a potential and promising candidate for diagnostic applications and measuring the refractive index of materials.

In this paper, we have analytically investigated the effects of temperature and electric field perpendicular to the silicene surface on the transverse electric wave propagation range in the frequency range of 1 to 30 THz. Unlike graphene, the atomic structure of a silicene composite is not flat, which makes the surface conductivity of silicene, in addition to the Fermi level, adjustable with an electric field perpendicular to the silicene surface. This property allows silicene to emit transverse electric waves over a wider range than graphene. According to the simulation results based on Kubo equations, per vertical electric field of 100 mV/Å, the propagation bandwidth of TE waves at temperatures of 5 K, 100 K, 200 K and 300 K are equal to 9.2 THz, THz 8, 1.3 THz and 0.9 THz, respectively. By increasing the vertical electric field to 200 mV/Å, the bandwidth for these temperatures will be 20.7 THz, 20.6 THz, 16.7 THz and 11.7 THz, respectively. In the vertical electric field to 300 mV/Å, these values ​​are 29 THz, 28.8 THz, 26.4 THz and 21.8 THz, respectively. The confinement length of TE waves in the propagation ranges has also been obtained, which has increased the trapping length with increasing temperature.

In this paper, a novel structure for silicon on insulator metal semiconductor field effect transistors (SOI MESFETs) is introduced using the heterogeneous Si/SiGe region. SiGe semiconductor is used to expand the effective width of the drift region inside the buried oxide (BOX) layer. Due to its properties such as high electron mobility, high electron drift velocity, and excellent radio frequency (RF) performance, it significantly increases the current density of drain and other DC and RF parameters. Also, to control the critical electric field, which determines the breakdown voltage of the device, as well as to reduce the parasitic capacitance to improve its frequency characteristics, an additional oxide region between the gate and drain and below a part of the gate region is used. Numerical simulation shows that the drain current density and breakdown voltage of the proposed device compared to the conventional structure has been improved by 120% and 37%, respectively, resulting in a 2 times increase in maximum output power density (Pmax). Also, the RF specifications of the new structure, including current gain (h21), unilateral power gain (U), and maximum available power gain (MAG), have been improved by 130%, 85%, and 65%, respectively. These specifications are proper for a device in high power and RF circuits like D-band applications.

In this paper, we designed and simulated a new TFET. Due to the band-to-band tunneling current mechanism, the TFETs show a low current and subthreshold slope of less than 60mV/dec. As a result, they can be a suitable alternative to MOSFET for use in low-power switching circuits. But its main disadvantage is its low on-state current compared to MOSFET. In this article, an optimized two-gate-two-material tunnel transistor structure is proposed in which the tunneling rate of carriers increased by adding two regions with inherent impurity compared to the common two-gate TFET structures. We simulated the proposed TFET in two dimensions using Silvaco-Atlas software and analyzed its results. The results are as follows: the on-state current (Ion=5.49×10-6A/µm), off current (Ioff=2×10-18A/µm), Subthreshold slope (SS=15.02mV/dec), and the Ion/Ioff =2.74×1012. The calculated results show the improvement of the DC parameters of the device.

Coronary Atherosclerosis is the leading cause of death and disability worldwide. Atherosclerosis could be detected noninvasively by coronary calcification, measured by calcium score in CT angiography. Dietary factors are influential in the evolution of coronary plaques, and one of the most prevalent drinks is black tea. We aimed to evaluate the effects of black tea on coronary calcium scores.

This cross-sectional analytical descriptive study was conducted on 200 candidates for CT angiography referred by their physician because their symptoms were suggestive of ischemia. A questionnaire was filled out for every participant, and the habit of tea drinking was asked and marked as none drinker, 1-3 cups per day and >3 cups per day.

89.5% of the participants consumed tea. The mean calcium score in patients who did not drink tea was 674.9±154.74 in those patients who drank 1-3 glasses per day, 269.5±46.9 and in those who drank more than three glasses of tea and was 261.1±45.2. There was a significant statistical relationship between calcium scores and tea intake, independent to other traditional risk factors (P= 0.001). Significant coronary artery plaques were also less prevalent in those who drank tea (36% and 41% in 1-3 and >3 cups, respectively) than non-drinkers (67%). Still, the number of involved vessels was not significantly different.

Regular black tea consumption could have protective effects on coronary artery calcification.

Many researches have focused on reducing the deleterious effects of oxidative stress in biological systems. The present study investigated the effect of palmitoleic acid on the oxidative stress parameters induced by palmitic acid on cardiomyocytes.
Rat cardiomyocytes were treated with 0.5 mM palmitate, palmitoleate,
and palmitate palmitoleate, or remained as control. Total antioxidant capacity (TAC) and Malondialdehyde (MDA) values were measured in both the cells and the media at 24h and 48h intervals.
While cellular TAC values decreased in the palmitic acid group compared to the control group (24%) at 48h time point (P In conclusion, the harmful effects of the oxidative stress induced by palmitate would be diminished by palmitoleate in the rat cardiomyocytes.

Co-supplementation of unsaturated fatty acids (FAs) with saturated FAs may decrease the adverse effects of saturated FA-induced lipotoxicity. The objective of the present study was to evaluate the effect of palmitoleic acid (unsaturated fatty acid) on palmitic acid (saturated fatty acid) induced lipotoxicity criteria in the primary culture of adult rat cardiomyocytes.
Cells were treated with 0.5 mM palmitic acid, palmitoleic acid, palmitic palmitoleic acids or remained untreated. The values of cellular triacylglycerol (TAG), diacylglycerol (DAG), DNA fragmentation and cellular viability were evaluated over 24 h, 48 h and 72 h time points.
Co-administration of palmitic and palmitoleic acids increased TAG values over 48 h and 72 h time points compared to the palmitic acid (34.37% and 62.79%, respectively; P Palmitoleic acid may be beneficial for diminishing adverse effects of palmitic acid in the rat cardiomyocytes through alterations in the molecule signaling levels.