Atomistic Quantum Transport Simulation of Multilayer Phosphorene Nanoribbon Field Effect Transistors

Few-layer black phosphorus is a semiconductor material, where its allotrope is called phosphorene; a new two-dimensional material which is discovered in 2014. In this paper, first we use the tight-binding method to implement a matrix representation for single-layer and multilayer structures of phosphorene nanoribbon (PNR) to define the Hamiltonian of the system. Second, we investigate the band structure and the band gap of multilayer PNRs. The band gap of armchair PNRs with 16 atoms across the width of PNR for single-layer, bilayer, and three-layer structures are obtained as 1.899, 1.224, and 0.937 eV, respectively. Third, we use the atomistic description of structure to simulate the performance characteristics of single and multilayer PNR field effect transistors (PNRFETs) by employing the non-equilibrium Green\u27s function (NEGF) formalism. Based on the properties of the material and device structures, Id-Vgs, Id-Vds characteristics, energy band diagram in the channel, and ION/IOFF are analyzed. The ON to OFF current ratio for single-layer, bilayer, and three-layer PNRFETs are increasing when the channel length increases from 5 nm to 15 nm. The current ratio for single-layer increases from 1277 for Lch=5 nm to 216.7×106 for Lch=15 nm. The ION/IOFF in single-layer PNRFET is higher in comparison with those values in bilayer and three-layer PNRFETs due to very small off-current in the single-layer PNRFET which in turn resulted from its larger band gap. The results show that the performance of PNRFET changes significantly depending on the number of phosphorene layers and the length of the channel of device

Comparison of The Effect of Ketogenic Diet and Low Caloric Diet On Weight Loss in Iranian Obese and Overweight Children

Abstract Overweight and obesity has increased in prevalence over the last two decades in many developed and developing countries including Iran. The aim of this present study was to compare the weight reduction effects of ketogenic and low calorie diets on overweight and obese Iranian children. Seventy-six overweight or obese children aged 9-16 years recruited from outpatient Ghaem Hospital, Nutritional Clinic, were randomized into two groups: a low calorie diet (n=38), a ketogenic diet (n=38). Both groups were treated for three months and followed up weekly. Fasting lipid profiles, blood sugar, uric acid, high-sensitivity C-reactive protein, , and weight were measured. Body fat percentages were measured using Bioimpedance Analysis (Tanita body composition analyzer, BC-418, Japan) for all subjects’ in each visit. Both ketogenic and low caloric diets reduced obesity indices including body fat percentage and improved lipid profiles (P0.05). However, low caloric diet had more potential beneficial effect on body fat percentage and lipid profile than ketogenic diet (

Physical specifications of photonic crystal slab lenses and their effects on image quality

Photonic crystal (PhC) lenses with negative refractive index have attractedintense interest because of their application in optical frequencies. In thispaper, 2-D PhC lenses with triangular lattice of cylindrical holes in dielectricmaterial are investigated. Variant physical parameters of the lens are introducedand their effects on the lens response are studied in detail. The effect ofthe surface termination is investigated by analyzing the power flux within thePhC structure. A new lens formula has been obtained which shows a linearrelation between source distance (distance between the source and the lens)and image distance (distance between the image and the lens) for any surfacetermination of the PhC lens. It is observed that the excitation of surfacewaves does not necessarily pull the image closer to the lens. The effects of thethickness and the lateral width of the lens are also analyzed.Validerad; 2012; 20120601 (sohsaf

Design of NIR-TERS system based on optimized grating on the AFM probe under radial polarized light for detection of molecular sample

To the best of our knowledge, it is for the first time thatTERS system in near-infrared (NIR) spectrum isreporting. The current study proposed a most favorableatomic force microscopy (AFM) tip based on anincorporated optimal grating structure close to the tipapex. The optimized M2 factor and the best spatialresolution are obtained as 5.9× 109 and 8.5 nmrespectively in the NIR range of radiation light. Theresults show that the optimized grating can effectivelyincrease the amount of intensity of electric field andimprove spatial resolution within the nanoslit between theAFM tip and substrate. The detection sensitivity ofmaterials can be done by our proposed AFM-TERSsystem. The difference between the maximumenhancement factors that are correlated to several undertest sample molecules show the selectivity potential ofthe proposed AFM-TERS system in material detectiontopic

Comparison of Novel Coronary Artery Disease Risk Factors between Obese and Normal Adolescent

Background: Coronary artery disease is considered as the most common cause of death in all societies including Iran. This study seeks to compare the new risk factors of coronary-artery diseases in obese adolescents and control group. Methods: In this cross-sectional study, amongst the obese adolescents registered in the nutrition clinic of Ghaem Hospital, 80 individuals were selected. As the control group, additional 80 adolescent students having the same gender and age as the obese group, but with normal weight were selected. These two groups were selected randomly and their serum level of vitamin D, anti-heat shock protein27 (HSP27), balance of oxidants and antioxidants, and homocysteine were determined and compared. Results: In this study, 42 (53.2%) and 37 (46.8%) of the obese and normal weight groups were male, respectively. The mean value of triglyceride, cholesterol, and LDL in the obese group was higher than the normal group, but the mean value for HDL, vitamin D, homocysteine, PAB (Preoxidant and Antioxidants Balance), and anti-HSP27 was not significantly different between the groups. In the base of homocysteine >15 µmol/l, 26.6% of the obese group had hyperhomocysteinemia, therefore homocysteine may be a new risk factor for coronary artery disease in obese adolescents (χ2=4.072; P value=0.091). Conclusion: The findings of this study showed that despite the presence of obesity in adolescence and adolescents, new risk factors are not present among them more than the control group. This was in contrast to what was seen in adults

Effect of a High Dairy Diet on Serum Antibody Titers to Heat Shock Protein 27 in Overweight and Obese Children

Objective: An immune response to heat shock proteins appears to be involved in atherogenesis. To date, there has been no report on the impact of dairy or calcium consumption on serum antibody titers to heat shock protein 27 (anti-HSP27). We have investigated whether an increase in dairy food consumption is capable of affecting serum antibody titers to heat shock protein 27 (anti-HSP27) level in children. Methods: Overweight and obese children (n=99, age: 12-18 y, body mass index: 27-40 kg/m2) were randomized to receive a calorie restricted diet providing a 500 kcal/d deficit from total energy expenditure and two (n=38), three (n=26) or four (n=35) servings of dairy products/day. Serum anti-HSP27 level in addition to the serum hs-CRP and lipid profile were measured at baseline and after 12 weeks. Findings: Serum anti-HSP27 concentrations did not change significantly in any of the mentioned groups. Serum hs-CRP and lipid profile did not change significantly either, apart from a significant increase in HDL-cholesterol in the low-dairy group. Conclusion: An increased intake of dairy products does not lead to a significant change in serum anti-HSP27 level in overweight and obese children