A 110–140 GHz Millimeter-Wave VCO Using Varactor and Bulk Effective Technique in 65 nm CMOS Process

In this paper, an enhanced voltage controlled oscillator (VCO) at center frequency 125 GHz with tuning rang of 24% is presented. The proposed idea is based on the tuning capacitance using MOS varactor. The structure is consisted of applying an MOS varactor capacitor to the drain and bulk (in parallel) of NMOS transistor in 65 nm CMOS standard technology. The obtained output of the proposed VCO at 2nd harmonic is tunable at 110–140 GHz frequency with applying?±?1.2 input tuning voltage. Simulation results of the proposed circuit are obtained after extracting post layout (with total chip size of 0.07 mm²) and confirm theoretical results. Compared to the resent designs, the obtained results indicate that the proposed circuit has high tuning range, low die area and a good figure of merit @ 1.2 power supply voltage.

     

Phenolics as antioxidants in garlic (Allium sativum L., Alliaceae)

The antioxidant activities of polar fractions of mature garlic bulbs and immature plants in four different model systems are presented. Antioxidant activity was evaluated as free radical-scavenging capacity (RSC), together with the effect on lipid peroxidation (LP). RSC was assessed by measuring the scavenging activity of garlic extracts on 2,2-diphenyl-1-picrylhydrazyl (DPPH) and hydrogen peroxide. Effects on LP were evaluated by following the activities of examined garlic extracts in Fe²⁺/ascorbate and Fe²⁺/H₂O₂ systems of induction. Investigated extracts reduced the DPPH radical formation (IC₅₀ ranging from 1.03 to 6.01 mg/ml) and neutralised H₂O₂ (IC₅₀ ranging from 0.55 to 2.01 mg/ml) in a dose-dependent manner. Strong inhibition of LP in both systems of induction was observed for all tested garlic extracts. Various levels of phenolics (0.05–0.98 mg gallic acid equivalents/g of dry extract) and flavonoid aglycones (4.16–6.99 μg quercetin equivalents/g of dry extract) in the investigated extracts of garlic could explain the obtained differences in these results only partially.     

Phenolic composition and comparison of antioxidant activity of alcoholic extracts of Peppermint (Mentha piperita)

Peppermint (Mentha piperita) has long been regarded as a food and medicinal plant. At the present work, the antioxidant activity of the methanol, ethanol and methanol/ethanol (1:1) extracts of leaf fraction through various in vitro models was investigated in Iranian peppermints for the first time. Total phenol, flavonoid and anthocyanin contents were also determined. Our results showed the alcoholic extracts had different responses with different antioxidant methods. The methanol extract had maximum phenol content (3.57 ± 0.26 g Gallic acid/100 g Peppermint powder) and showed best superoxide radical (47.05 ± 0.85 %) and hydrogen peroxide (91.05 ± 1.50 %) scavenging activities. The methanol/ethanol (1:1) extract had maximum flavonoid (3.33 ± 0.12 g quercetin/100 g Peppermint powder) and anthocyanin contents (1.74 ± 0.21 g/100 g Peppermint powder) and showed best DPPH radical scavenging activity (82.82 ± 2.57 %, IC₅₀ = 10.02 ± 0.63 mg/mL) as well as ferric reducing power (184.22 ± 14.10 μmol/100 g Peppermint powder). The ethanol extract only showed the highest nitric oxide radical scavenging activity (80.13 ± 7.12 %). Chlorogenic acid, rutin, and caffeic acid were found by HPLC analysis of the main phenolic components. These results show, Peppermint alcoholic extracts can be used as a natural antioxidants to reduce oxidative stress in human beings and as a possible food supplement or in pharmaceutical applications.     

Antioxidant activity of medicinal plant extracts in cookies

The antioxidant activity of ethanolic extracts of parsley, buckthorn, mint, caraway, and their mixture "Vitalplant" was evaluated, and the potential of "Vitalplant" mixture extract to retard the process of lipid oxidation in cookies was tested. The antioxidant activity was estimated by 2 direct (ESR) and 4 indirect (spectrophotometric) tests and correlated with the total phenolic and flavonoid content. The potential of "Vitalplant" mixture extract to retard the process of lipid oxidation in cookies was measured by thiobarbituric acid (TBA)-reactive-substances assay (TBARS) and DPPH˙ (1,1-diphenyl-2-picryl-hydrazyl) test. Significantly different (P < 0.05) amounts of total phenolics were found among extracts in the following order: mint > buckthorn > "Vitalplant" > parsley > caraway. Total flavonoid content varied from 0.510% (parsley) to 2.05% ("Vitalplant"). A statistically significant correlation was found between IC(50) values on DPPH˙ and total flavonoid content of the samples (r=- 0.94, P < 0.05) and between IC(50) values on DPPH˙ and IC(50) values on O(2) (·-) scavenging activity (r= 0.89, P < 0.05). A correlation between reducing activity and total phenolic content was found to be positive and statistically significant (r= 0.94, P < 0.05). "Vitalplant" mixture exhibited a relatively high antioxidant activity in most of the tests, which can be explained by synergistic effects of the ingredients of which it is composed. Finally, "Vitalplant" extract addition (2%, 4%, and 6%) improved antioxidant activity and oxidative stability of the cookies in dose-dependent manner. PRACTICAL APPLICATION: Supplementation of cookies with a mixture of Petroselini fructus, Frangulae cortex, Mentha piperitae folium, Carvi fructus can retard the process of lipid oxidation and elevate antioxidant activity of the final product.     

Comparison of energy consumption for reader anti-collision protocols in dense RFID networks

Wireless Networks - Radio-frequency identification (RFID) is known as a universal technology and has been in the center of attention in the past few years. Readers and tags constitute the main...     

Design of MMIC oscillators using GaAs 0.2 μm PHEMT technology

We propose a feedback type oscillator and two negative resistance oscillators.These microwave oscillators have been designed in the S band frequency.A relatively symmetric resonator is used in the feed...