Through-membrane electron-beam lithography for ultrathin membrane applications

We present a technique to fabricate ultrathin (down to 20 nm) uniform electron transparent windows at dedicated locations in a SiN membrane for in situ transmission electron microscopy experiments. An electron-beam (e-beam) resist is spray-coated on the backside of the membrane in a KOH- etched cavity in silicon which is patterned using through-membrane electron-beam lithography. This is a controlled way to make transparent windows in membranes, whilst the topside of the membrane remains undamaged and retains its flatness. Our approach was optimized for MEMS-based heating chips but can be applied to any chip design. We show two different applications of this technique for (1) fabrication of a nanogap electrode by means of electromigration in thin free-standing metal films and (2) making low-noise graphene nanopore devices

Comparison of knowledge, attitude and practice of Urban and rural households toward iron deficiency anemia in three provinces of Iran

Background: Lack of nutritional knowledge is one of the most important reasons of nutritional problems and consequently improper practice, which can lead to several complications. This study has been designed in order to compare knowledge, attitude and practices of the urban and rural households regarding iron deficiency anemia (IDA) in Boushehr, Golestan and Sistan & Balouchestan provinces in 2004. Methods: The sampling method at household's level in each province was the single-stage cluster sampling with equal size clusters. The necessary data were gathered with a structured questionnaire and via the interviews between the questioners and the eligible people in each household. Comparison of frequency of variables between urban and rural areas were tested by chi square test. Results: A total of 2306 households were selected as overall sample size. In urban areas, people recognized iron food sources better than rural areas. Knowledge level of respondents about vulnerable group for IDA and the favorite attitude of households toward IDA were better in urban areas of Sistan & Blouchestan and Golestan provinces. In Sistan & Balouchestan and Golestan, rural households who drank tea immediately before or after meal was more than urban ones. The majority of pregnant and lactating mothers (except for rural areas of Bushehr) did not take iron supplement regularly. Less than 60 percent of children used iron drop regularly. Conclusion: Knowledge, attitude, and practice levels of households toward IDA were not acceptable. One of the best ways of improving nutritional practice is nutritional education with focus on applying available food resources

The effects of resveratrol on the expression of VEGF, TGF-β, and MMP-9 in endometrial stromal cells of women with endometriosis

Resveratrol is a phytochemical with anti-angiogenic, anti-inflammatory, and antioxidant properties. The present study has evaluated the effect of resveratrol on the expression of vascular endothelial growth factor (VEGF), transforming growth factor-β (TGF-β) and matrix metalloproteinase-9 (MMP-9) as factors related to endometriosis progression. Thirteen eutopic (EuESCs) and 8 ectopic (EESCs) endometrial stromal cells from women with endometriosis and 11 control endometrial stromal cells (CESCs) were treated with resveratrol (100 µM) for 6, 24 and 48 h. The gene and protein expression levels of VEGF, TGF-β, and MMP-9 were measured using real-time PCR and ELISA methods, respectively. Results showed that the basal gene and protein expression of VEGF and MMP-9 were higher in EESCs compared to EuESCs and CESCs (P < 0.01 to < 0.001 and P < 0.05 to < 0.01 respectively). Also, resveratrol treatment decreased the gene and protein expression of VEGF and MMP-9 in EuESCs, EESCs and CESCs (P < 0.05 to < 0.01 and P < 0.05 to < 0.01 respectively) and gene and protein expression of TGF-β in EESCs and EuESCs (P < 0.05 to < 0.01). The effect of resveratrol in reduction of VEGF gene expression was statistically more noticeable in EESCs compared to EuESCs and CESCs (P < 0.05). According to the findings, resveratrol may ameliorate endometriosis progression through reducing the expression of VEGF, TGF-β, and MMP-9 in endometrial stromal cells (ESCs). © 2021, The Author(s)

Effect of fish oil on circulating asymmetric dimethylarginine and adiponectin in overweight or obese patients with atrial fibrillation

Obesity and adipose-derived peptides might be involved in the pathogenesis of atrial fibrillation (AF). Adiponectin plays a major role in the modulation of several metabolic pathways, and asymmetric dimethylarginine (ADMA) has been suggested to be predictive of AF and associated adverse events. The aim of this study was to investigate the effect of fish oil supplementation on circulating adiponectin and ADMA in overweight or obese patients with persistent AF. In this randomized, double-blind, placebo-controlled trial, 80 overweight or obese (body mass index (BMI) � 25 kg/m2) patients with persistent AF were randomly assigned to two groups to receive either 2 g/day fish oil or placebo, for 8 weeks. Serum levels of adiponectin and ADMA, and anthropometric indexes were measured. This study showed that serum adiponectin concentrations increased significantly following fish oil supplementation compared with the placebo group (13.15 ± 7.33 vs. 11.88 ± 6.94 µg/ml; p =.026). A significant reduction was also observed in serum ADMA levels in the fish oil compared with the placebo group following the intervention (0.6 ± 0.13 vs. 0.72 ± 0.15 µmol/L; p =.001). The changes in serum adiponectin and ADMA concentrations remained significant after adjustments for baseline values, age, sex, and changes of BMI and waist circumference (p =.011 and p =.001, respectively). In conclusion, 8 weeks supplementation with fish oil increased serum adiponectin and decreased ADMA concentrations in overweight or obese patients with persistent AF. As adiponectin and ADMA are suggested to be involved in many pathways associated with AF, the current findings might be promising in the clinical management of this disease, an issue that needs further investigations. © 2020 The Authors. Food Science & Nutrition published by Wiley Periodicals, Inc

Substrate engineering for Ni-assisted growth of carbon nano-tubes

The growth of carbon multi-walled nano-tubes (MWCNTs) using metal catalyst (e.g. Ni, Co, and Fe) has been extensively investigated during the last decade. In general, the physical properties of CNTs depend on the type, quality and diameter of the tubes. One of the parameters which affects the diameter of a MWCNT is the size of the catalyst metal islands. Considering Ni as the metal catalyst, the formed silicide layer agglomerates (island formation) after a thermal treatment. One way to decrease the size of Ni islands is to apply SiGe as the base for the growth. In this study, different methods based on substrate engineering are proposed to change/control the MWCNT diameters. These include (i) well-controlled oxide openings containing Ni to miniaturize the metal island size, and (ii) growth on strained or partially relaxed SiGe layers for smaller Ni silicide islands

Evolution of high aspect ratio and nano-grass structures using a modified low plasma density reactive ion etching

We report a modified deep reactive ion etching method to realize high aspect ratio features and nano-grasses on silicon substrates. This etching technique uses sequential etching and passivation sub-cycles and it is based on three gases of H2, O2 and SF6 in the presence of rf-plasma. By adjusting the etching parameters such as the flows of various gases, the plasma power and duration of each cycle, the process can be controlled to obtain high aspect ratio vertical structures on silicon substrates. Features with aspect ratios of the order of 30–50 and heights of the order of 25–30 μm are obtained. On the other hand, one can program the etching parameters to achieve grass-full structures in desired places and with pre-designed patterns. The formation of nano-grass on silicon surface, improves its wetability with water and oil spills. This property has been used to entrap carbon nanotubes onto nano-structured surfaces in desired places

Highly selective and responsive ultra-violet detection using an improved phototransistor

An ultra-violet (UV) phototransistor with 700x200 lm2 gate area decorated with vertically aligned Zinc Oxide (ZnO) nanorods to enhance UV responsivity is designed and manufactured. Spectral responsivity of the device was measured for wavelengths ranged from 200 to 1100 nm of the electromagnetic spectrum in different transistor working regions. The best responsivity was achieved at sub-threshold and very weak inversion region. In order to enhance UV range selectivity, oxygen plasma has been employed on the nanorods, and consequently, nearly 3-fold improvement in its relative sensitivity at 375 nm was achieved. The final manufactured phototransistor shows a highly selective response of 24 kA/W in the UV range.MicroelectronicsElectrical Engineering, Mathematics and Computer Scienc

TiO2 nanotube formation by Ti film anodization and their transport properties for dye-sensitized solar cells

In this paper, we present the synthesis of TiO2 nanotube (NT) arrays formed by anodization of Ti film deposited on a fluorine-doped tin oxide-coated glass substrate by direct current magnetron sputtering. NH4F/ethylene glycol electrolyte was used to demonstrate the growth of stable nanotubes at room temperature. TiO2 NTs as long as 4.8 ?m with the high expansion factor to the initial sputtered Ti film (2 ?m) were obtained, showing little undesired dissolution of the metal in the electrolyte during anodization. The average pore size and wall thickness of NTs were about 70 and 30 nm, respectively. Structural investigations on the transparent NT arrays reveal the presence of anatase phase after annealing. The NTs were sensitized by the N719 complex and the resultant photoelectrodes were incorporated into dye sensitized solar cells (DSSCs). The conversion efficiency of 1.97 % was obtained under AM 1.5 illumination and the open circuit voltage, short circuit current density and the fill factor were 0.59 V, 6.71 mA/cm2 and 0.50, respectively. Investigation of the electron transport of the DSSCs by electrochemical impedance spectroscopy showed that the electron diffusion length (8.6 ?m) was higher than NTs’ height. It was also observed that the electron transport resistance measured in NT DSSC was lower compared to the reported TiO2 nanoparticle one.MicroelectronicsElectrical Engineering, Mathematics and Computer Scienc

Surveying the amount of junk food consumption in under-3-year-old children of rural and urban areas, 1998

Background: With respect to the lack of sufficient vitamin, calorie, minerals and proteins in junk foods, they have the ability of filling child's stomach and decreasing their appetite, thus, he/she would miss the opportunity of a healthy nutrition. Unfortunately, the nutrition profile of under-3-year-old children is not determined in our country, so the present study was conducted over under-6-year-old children of urban and rural areas in 1998. Materials and Methods: It was a descriptive study. The study population included 16418 under-3-year-old children of urban and rural areas. Nutrition pattern was determined through a questionnaire.Results: 47.1 of urban and 51.2 of rural children aged 6-12 months have used junk foods including coca, sweets, chocolate and so on. For children aged 12-24 months these figures were 90.3 and 87.7, respectively. Main nutrients including meat, egg and dairy were used 3 times a week, however, these junk foods were used 9 times a week.Conclusion: With respect to the known complications of junk food consumption, further studies considering the traditional foods through educational programs should be kept in mind. Needless to say, promoting parents' knowledge could be helpful

Monolithically Integrated Light Feedback Control Circuit for Blue/UV LED Smart Package

Given the performance decay of high-power light-emitting diode (LED) chips over time and package condition changes, having a reliable output light for sensitive applications is a point of concern. In this study, a light feedback control circuit, including blue-selective photodiodes, for blue/ultraviolet (UV) LED, has been designed and implemented using a low-cost seven-mask BiCMOS process. The feedback circuit was monolithically integrated in a package with four high-power blue LED chips. For sensing the intensity of exact colored blue/UV light in the package, selective photodiodes at 480-nm wavelength were implemented. An opamp-based feedback circuit combined with a high-power transistor controls the output light based on real-time sensor data. The whole system is a low-cost integrated package that guarantees a stable and reliable output light under different working conditions. Output light can be also controlled linearly by a reference input voltage.Electronic Components, Technology and MaterialsElectronic