Sharif Digital Repository

Abstract: In this study, an efficient, rapid and simple plant-mediated green sol–gel auto-combustion procedure was presented to synthesis magnesium–cobalt ferrite (MgCoFe2O4) nanocatalyst using an aqueous extract of apple skins as a chelating/combustion agent. The catalyst was assessed by multiple techniques, including FT-IR, XRD, FE-SEM, EDS, elemental mapping, TGA-DTA and VSM. Then, the catalytic potential of the as-prepared MgCoFe2O4 nanocatalyst was examined in the three-component condensation reaction of 1,3-dimethyl barbituric acid, aldehydes and malononitrile for the one-pot synthesis of pyrano[2,3-d]pyrimidinedione and their bis-derivatives. The obtained results indicated the... 

Abstract: In this study, an efficient, rapid and simple plant-mediated green sol–gel auto-combustion procedure was presented to synthesis magnesium–cobalt ferrite (MgCoFe2O4) nanocatalyst using an aqueous extract of apple skins as a chelating/combustion agent. The catalyst was assessed by multiple techniques, including FT-IR, XRD, FE-SEM, EDS, elemental mapping, TGA-DTA and VSM. Then, the catalytic potential of the as-prepared MgCoFe2O4 nanocatalyst was examined in the three-component condensation reaction of 1,3-dimethyl barbituric acid, aldehydes and malononitrile for the one-pot synthesis of pyrano[2,3-d]pyrimidinedione and their bis-derivatives. The obtained results indicated the... 

In this paper, LM pectin production from commercial apple pectin by using acid, alkali and ammonia methods in the presence of ethanol was studied. Also, the effect of different parameters such as, temperature, time, acid, alkali and ammonia treatment in LM pectin production were evaluated. In all the experiments, low temperature showed a better influence from a recovery, purity and low de-polymerization viewpoint. Optimum conditions in the acid method reached at pH = 2, t = 17 hrs and T = 30°C, in the alkaline method reached at pH = 11, t = 3 hrs and T = 5°C and in the ammonia method reached at 2 N ammonia and T = 5°C, were determined. © Sharif University of Technology  

The quality of fresh apple fruits is a major concern for consumers and manufacturers. Classification of these fruits according to their ripening stage is one of the most decisive factors in determining their quality. In this regard, the aim of this work is to develop a new method for non-destructive classification of the ripening state of Fuji apples using hyperspectral information in the visible and near-infrared (Vis/NIR) regions. Spectra of 172 apple samples in the range from 450 to 1000 nm were studied, which were selected from four different ripening stages. A convolutional neural network (CNN) model was proposed to perform the classification of the samples. The proposed method was... 

The flux behavior during the industrial cross-flow ultrafiltration of apple juice in a batch process was modeled using a combination of the fouling and concentration polarization models. It was observed that the major flux reduction was at the beginning and at the end of operation due to fouling and increasing solute concentration in the feed tank, respectively. The fouling phenomenon was analyzed by classical and empirical models and it was shown that the empirical one has the best correlation within less than 0.3% error for each experiment. The most significant advantage of this model is its ability to predict a steady flux, while other models predict zero flux at infinite time, which is... 

Declining permeate flux and increasing retentate solute concentration during a full scale apple juice ultrafiltration process was investigated. A modified equation and procedure was used for predicting retentate solute concentration (pectin) in the system. Solute concentration in the retentate was indirectly evaluated using the measured values of viscosity, temperature and Brix. The gel-polarization model was then used to analyze the collected data and a good agreement was observed between the experimental data and the model predictions. Fitted model parameters were very close to the published literature values for similar studies in pilot scale systems. According to the model, the optimum... 

A headspace solid-phase microextraction (HS-SPME) method was developed for the trace determination of geosmin in water and apple juice samples. A poly(dimethylsiloxane) (PDMS) fiber was synthesized as coated fiber using sol-gel methodology. After performing the extraction in the headspace, the fiber was introduced directly into the injection port of a gas chromatography-mass spectrometry (GC-MS) using electron impact (EI) ionization mode. One-at-the-time optimization strategy was applied to investigate and optimize important extraction parameters such as extraction temperature and time, ionic strength, headspace volume, and desorption temperature and time. The analytical data exhibited an... 

This study focuses on the spectrochemical estimation of pH and titratable acidity (TA) of apples of Fuji variety at different stages of ripening. A novel approach is proposed for near-infrared (NIR) spectral analysis using hybrid machine learning methods that combine artificial neural networks (ANN) and metaheuristic algorithms. One hundred twenty samples were collected at three ripening stages and spectral data within two bands of NIR were extracted from each sample to predict the acidity properties. Alternatively, the 4 most effective wavelengths were also selected using a hybrid of ANN and the cultural algorithm. The experimental results prove that the models using spectral bands and the... 

Nondestructive estimation of physicochemical properties, post-harvest physiology, and level of ripeness of fruits is essential to their automated harvesting, sorting, and handling. Recent research efforts have identified machine vision systems as a promising noninvasive nondestructive tool for exploring the relationship between physicochemical and appearance characteristics of fruits at various ripening levels. In this regard, the purpose of the current study is to provide an intelligent algorithm for estimating two physical properties including firmness, and soluble solid content (SSC), three chemical properties viz. starch, acidity, and titratable acidity (TA), as well as detection of the... 

Pectin from two different plant sources: apple and sugar beet was studied. Apple pectin was modified by chemical treatments such as: acid, alkali and ammonia, so as to obtain an ester level equal to or less than 50 %, which is described as low methoxyl (LM) pectin. LM pectin form gels with significant characteristic. In this study, de-esterification of apple pectin with acid treatment resulted in gel specification with higher molecular weight and viscosity. Acid treatment resulted in pectin with average molecular weight of 32000 Dalton. Pectin was extracted from sugar beet pulp by acid and alkali treatments. The quality of gel formation and water uptake was improved using sugar source... 

A high-throughput micro-solid-phase extraction device based on a 96-well plate was constructed and applied to the determination of pesticide residues in various apple samples. Butyl methacrylate and ethylene glycol dimethacrylate were copolymerized as a monolithic polymer and placed in the cylindrically shaped stainless-steel meshes of 96-micro-solid-phase extraction device and used as an extracting unit. Before the micro-solid-phase extraction, microwave-assisted extraction was employed to facilitate the transfer of the pesticide residues from the apple matrix to liquid media. Then, 1 mL of the aquatic samples was transferred into the 96-well plate and the 96-micro-solid-phase extraction... 

Underlying mechanisms of obesity-related back pain remain unexplored. Thus, we aim to determine the effect of obesity and its shapes on the spinal loads and the associated risks of injury. Obesity shapes were initially constructed by principal component analysis based on datasets on 5852 obese individuals. Spinal loads, cycles to vertebral failure and trunk stability margin were estimated in a subject-specific trunk model taking account of personalized musculature, passive ligamentous spine, obesity shapes, segmental weights, spine kinematics and bone mineral density. Three obesity shapes (mean and extreme abdominal circumferences) at three body weights (BWs) of 86, 98 and 109 kg were... 

It is reported that approximately 40 million people are suffering from dementia, globally. Dementia is a group of symptoms that affect neurons and cause some mental disorders, such as losing memory. Alzheimer's disease (AD) which is known as the most common cause of dementia, is one of the top medical care concerns across the world. Although the exact sources of the disease are not understood, is it believed that aggregation of amyloid-beta (Aβ) outside of neuron cells and tau aggregation or neurofibrillary tangles (NFTs) formation inside the cell may play crucial roles. In this paper, we are going to review studies that targeted inhibition of amyloid plaque and tau protein tangle formation,...