Incidence of aflatoxin M1 in human breast milk in Tehran, Iran

This study examined the exposure of infants to aflatoxin M1 (AFM1) and of lactating mothers to aflatoxin B1 (AFB1), using AFM1 in breast milk as a biomarker for exposure to AFB1. An enzyme-linked immunosorbent assay (ELISA) was modified for the analysis of AFM1 in breast milk samples from 160 women in Tehran, Iran. AFM1 was detected in 157 samples by average concentration of 8.2 ± 5.1 ng/kg (range 0.3–26.7 ng/kg).The concentration of AFM1 in one sample was higher than the maximum tolerance limit accepted by European Union and USA (25 ng/kg), but in 55 samples was higher than the maximum concentration recommended by Australia and Switzerland (10 ng/kg).Logistic regression Analysis failed to show significant correlation between AFM1 and gestational age, education, postnatal age, gender, nationality, clinical condition, the number of family member, the number of children, type and amount of dairy consumption, vegetable, fruits, oil and meat. But it was significant relation to the cereal consumption, also to the height at birth.     

Electrochemical impedance studies of methanol oxidation on GC/Ni and GC/NiCu electrode

The electro-oxidation of methanol on nickel and nickel–copper alloy modified glassy carbon electrodes (GC/Ni and GC/NiCu) in a 1 M NaOH solution at different concentrations of methanol was studied by the method of ac-impedance spectroscopy. Two semicircles in the first quadrant of a Nyquist diagram were observed for electro-oxidation of methanol on GC/Ni corresponding to charge transfer resistance and adsorption of intermediates. Electro-oxidation of methanol on GC/NiCu shows negative resistance in impedance plots as signified by semi-circles terminating in the second quadrant. The impedance behavior shows different patterns at different applied anodic potential. The influence of the electrode potential on impedance pattern is studied and a mathematical model was put forward to quantitatively account for the impedance behavior of methanol oxidation. At potentials higher than 0.49 V vs. Ag/AgCl, a pseudoinductive behavior is observed but at higher than 0.58 V, impedance patterns terminate in the second quadrant. The conditions required for this behavior are delineated with the use of the impedance model.     

A 0.5–1 GHz single stage linear-in-decibel VGA with 80 dB gain range in 0.18 μm CMOS

Communication systems require a wide gain range. For example the code-division multiple access system (CDMA) requires more than 80 dB of gain range so that, many variable gain amplifiers (VGAs) must be used, resulting in high power consumption and low linearity because of VGA non-linearity factors. In this paper, a one-stage VGA in 0.18 μm technology is presented. The VGA based on the class AB power amplifier is designed and simulated for a high linearity and an 80 dB tuning range. For the linear-in-decibel tuning range, transistors in sub-threshold region is used. The current control circuit of the VGA changes gain continuously from ?68 to 18 dB at 0.5 GHz and ?60 to 20 dB at 1 GHz with gain error of less than 2 dB. The power consumption enjoys a highest value about 13.5 mW in the maximum gain and P1dB is also about ?3.4 dBm at 0.5 GHz and 2.2 dBm at 1 GHz.     

Variation in the Optical Properties of the SiC-SiO<Subscript>2</Subscript> Composite Antireflection Layer in Crystalline Silicon Solar Cells by Annealing

This study showed the effects of annealing on a sol–gel-derived SiC-SiO₂ composite antireflection (AR) layer and investigated the optical and photovoltaic properties of crystalline silicon (Si) solar cells. The SiC-SiO₂ composite AR coating showed a considerable decrease in reflectance from 7.18% to 3.23% at varying annealing temperatures of 450–800°C. The refractive indices of the SiC-SiO₂ composite AR layer were tuned from 2.06 to 2.45 with the increase in annealing temperature. The analysis of the current density–voltage characteristics indicated that the energy conversion efficiencies of the fabricated Si solar cells gradually increased from 16.99% to 17.73% with increasing annealing temperatures of 450–800°C. The annealing of the SiC-SiO₂ composite AR layer in Si solar cells was crucial to improving the optical, morphological, and photovoltaic properties.     

Accurate analysis of carbon nanotube interconnects using transmission line model

A new technique for analysing the time-domain response of carbon nanotube (CNT) interconnects, based on transmission line modelling, that takes the effects of both contact and fundamental (quantum) resistances into account is introduced. A new sixth-order linear parametric expression for the transfer function of these lines has been presented for the first time. For verification purposes, the step response of a driver-CNT bundle-load configuration for a 32 nm technology node, using the new technique and HSPICE simulation have been compared, with which the obtained results show an excellent match. Also the effect of contact resistance on the step response, especially the propagation delay, has been studied. The obtained results show that for the length of a CNT bundle equal to 50 mum with the diameter of each individual CNT 1 nm, the propagation delay changes from 0.138 to 5.58 ns for the contact resistance values from 1 to 50 k Omega, i.e. a variation range of 39.43 times the minimum value. The related delay variations for the length values 200 mum, 500 mum and 1000 mum, are 31.37, 22.61 and 15.42 times the minimum value, respectively.     

Hepatoprotective effect of Cassia obtusifolia seed extract and constituents against oxidative damage induced by tert‐butyl hydroperoxide in human hepatic HepG2 cells

The aim of the present study was to investigate the hepatoprotective effects of different soluble fractions of methanolic derived Cassia obtusifolia seeds extract (COE) and its active components in tert‐butyl hydroperoxide (t‐BHP)‐induced oxidative stress in HepG2 cells. Among the tested fractions, the ethyl acetate (EtOAc) fraction was the most active hepatoprotective fraction. From the active EtOAc fraction, six anthraquinones (alaternin, emodin, aloe emodin, 2‐hydroxyemodin 1‐methyl ether, chryso‐obtusin‐2‐O‐β‐d ‐glucoside, and questin) and one naphthopyrone glycoside (cassiaside) were isolated. The cytotoxic effect in 200 µM t‐BHP‐induced HepG2 cells was inhibited by COE and their bioactive compounds. The protective effect of COE in 200 µM t‐BHP‐induced HepG2 cells may be associated with positive regulation of glutathione (GSH) and decreased in reactive oxygen species (ROS) formation of their bioactive compounds. The increased ROS and decreased GSH levels observed in t‐BHP‐treated HepG2 cells were ameliorated by pretreatment with cassiaside, alaternin, and aloe emodin, indicating that the hepatoprotective effects of these major constituents are mediated by induction of cellular defense against oxidative stress. Overall, COE displayed a significant cytoprotective effect against oxidative stress, which may most likely be because of active compounds like cassiaside, alaternin, and aloe emodin in COE, which leads to maintenance of the normal redox status of cells.

Practical applications

The dried and roasted seeds of Cassia obtusifolia are commonly consumed as brew tea and medicinal foods in Korea. The seeds have multiple therapeutic actions related to the treatment of liver disease, dementia, diabetes, eye inflammation, photophobia and lacrimation, dysentery, headache, as well as dizziness. The present study demonstrates the hepatoprotective effect through prevention of oxidative stress, suggesting that C. obtusifolia and its constituents may have beneficial effects in preventing hepatic diseases.     

Electrocatalytic oxidation of methanol on Ni and NiCu alloy modified glassy carbon electrode

Nickel and nickel–copper alloy modified glassy carbon electrodes (GC/Ni and GC/NiCu) prepared by galvanostatic deposition were examined for their redox process and electrocatalytic activities towards the oxidation of methanol in alkaline solutions. The methods of cyclic voltammetery (CV) and chronoamperometry (CA) were employed. The cyclic voltammogram of NiCu alloy demonstrates the formation of β/β crystallographic forms of the nickel oxyhydroxide under prolonged repetitive potential cycling in alkaline solution. In CV studies, in the presence of methanol NiCu alloy modified electrode shows a significantly higher response for methanol oxidation. The peak current of the oxidation of nickel hydroxide increase is followed by a decrease in the corresponding cathodic current in presence of methanol. The anodic peak currents show linear dependency with the square root of scan rate. This behavior is the characteristic of a diffusion controlled process. Under the CA regime the reaction followed a Cottrellian behavior and the diffusion coefficient of methanol was found to be 2 × 10⁻⁶ cm² s⁻¹ in agreement with the values obtained from CV measurements.     

An experimental design-based evaluation of sensitivities of MEPDG prediction: investigating main and interaction effects

The mechanistic–empirical pavement design guide (MEPDG) uses mechanistic–empirical models by analysing the impacts of traffic, climate, materials and pavement structure to predict performances of pavement. The MEPDG software uses a three-level hierarchical input to predict performance in terms of terminal International Roughness Index, permanent deformation, total cracking (reflective and alligator), asphalt concrete (AC) thermal fracture, AC bottom-up fatigue cracking and AC top-down fatigue cracking. However, these inputs with different levels of accuracy may have significant impact on performance prediction. This study focuses on the sensitivity of the inputs of MEPDG distresses to identify the effect of the accuracy level of inputs based on experimental design. A local sensitivity analysis is carried out to identify the main effect of inputs considering them as independent variables. Interaction effects are also analysed based on random combination of the inputs. Sensitive input variables and their combinations are evaluated through a multiple regression analysis for respective distresses.     

A novel ultra low power ASK demodulator for a passive UHF RFID tag compatible with C1 G2 EPC standard protocol

In order to reduce the power consumption of RFID tags and increase the reading range of RFID systems, this paper proposes an ASK demodulator that uses a new approach to reduce the threshold voltage of diode connected MOS transistors as an obstacle in the design of the envelope detector. Also, an ultra low power comparator is used for further power reduction. This circuit has been simulated in a 0.18 μm CMOS technology to satisfy EPC Class 1 Generation 2 standard protocol emphasizing on the reduction of power consumption. The proposed circuit can correctly demodulate the minimum input RF signal amplitude of 180 mV for modulation depths of 55–100 % with 40–160 kb/s data rates. A total power consumption of less than 290 nW is achieved at a 1.2 V power supply. Effects of the input signal additive white noise as well as the process and temperature variations on the signal demodulation is also investigated in this paper.     

Brain Tumor Auto-Segmentation on Multimodal Imaging Modalities Using Deep Neural Network

Due to the difficulties of brain tumor segmentation, this paper proposes a strategy for extracting brain tumors from three-dimensional Magnetic Resonance Image (MRI) and Computed Tomography (CT) scans utilizing 3D U-Net Design and ResNet50, taken after by conventional classification strategies. In this inquire, the ResNet50 picked up accuracy with 98.96%, and the 3D U-Net scored 97.99% among the different methods of deep learning. It is to be mentioned that traditional Convolutional Neural Network (CNN) gives 97.90% accuracy on top of the 3D MRI. In expansion, the image fusion approach combines the multimodal images and makes a fused image to extricate more highlights from the medical images. Other than that, we have identified the loss function by utilizing several dice measurements approach and received Dice Result on top of a specific test case. The average mean score of dice coefficient and soft dice loss for three test cases was 0.0980. At the same time, for two test cases, the sensitivity and specification were recorded to be 0.0211 and 0.5867 using patch level predictions. On the other hand, a software integration pipeline was integrated to deploy the concentrated model into the webserver for accessing it from the software system using the Representational state transfer (REST) API. Eventually, the suggested models were validated through the Area Under the Curve–Receiver Characteristic Operator (AUC–ROC) curve and Confusion Matrix and compared with the existing research articles to understand the underlying problem. Through Comparative Analysis, we have extracted meaningful insights regarding brain tumour segmentation and figured out potential gaps. Nevertheless, the proposed model can be adjustable in daily life and the healthcare domain to identify the infected regions and cancer of the brain through various imaging modalities.