Sharif Digital Repository

Wastewater, especially with heavy metal contamination, is a global environmental concern. Numerous techniques have been tested for online controlling and monitoring the concentration of heavy metal ions; yet, there are many challenges in performing these techniques. Biosensor is cheap, easily available, simple, fast, selective, sensitive, and repeatable so it is an excellent alternative for the detection and quantification of hazardous particles in the wastewater. In this study, a Nano biosensor with high detection of copper ions has been fabricated. PEDOT:PSS as a highly conductive polymer is coupled with gold nanoparticles to modify the surface of graphite electrode and results in higher... 

Due to the increased public awareness about the role of food on health, an increased interest of consuming fortified food has grown rapidly. Probiotic bacteria and DHA poly-unsaturated fatty acid are two major bioactive ingredients becoming increasingly popular in food fortification industry due to their beneficial effects. However, high susceptibility of probiotic bacteria during production, maintenance and digestion in acidic and enzymatic conditions of gastrointestinal tract results in decreasing the survivability and therefore reducing health effects in body. Besides, having multiple double bonds in the structure of DHA fatty acid leads to oxidative degradation that produces volatile... 

In this research, carbon nanotubes (CNTs) and CNT coated by titanium dioxide (TiO2) were used as adsorbents for desulfurization. Photocatalytic oxidation by titanium dioxide Degussa P-25 nanoparticles (as photocatalyst) immobilized on a porous and low-density support called “perlite” and CNT/TiO2 was perused. TiO2-coatings were prepared by liquid phase deposition method.This is a wet process for the formation of metal oxide thin films on substrates. The coating of nanotubes with TiO2 was confirmed by IR and EDAX and morphological properties were observed by SEM analysis.The physical properties of adsorbents were determine using BET.Dibenzothiophene (DBT)dissolved in acetonitrile was used as... 

Dietary CLA production for medicinal purposes needs a safe and selective process. Biological production methods meet this goal. In this study, the microbial species that was suitable for CLA production was selected; then the CLA produced by bioconversion methods was utilized to produce CLA-enriched triglycerides by trans-esterification. Also the biochemical kinetics of CLA production and esterification reactions to produce CLA-enriched triglycerides was studied. In the presence of two substrates, the kinetics of enzymatic reaction was studied. Then the factors influencing on the microbial yield and CLA production including reaction conditions (reaction time, cell concentration and substrate... 

Theanine is a non-protein amino acid which was first isolated from tea plant leaves (Camellia sinensis) and also found in a mushroom named Xerocomus badius and some other Camellia species such as C.japonica and C.sasanqua. Theanine comprises about 50% of amino acids in tea and 1-2% of dry weight of tea leaves. It contributes to the umami taste and unique flavor to tea infusion and has many physiological and pharmaceutical effects such as anti-tumor and anti-cancer activity, neuroprotection, antihypertensive, relaxation, increased focus and anti-obesity effects. So this compound is essential for human body but is not synthesized in it and should be administrated orally. In recent years, study... 

Polymerase Chain Reaction (PCR) is a process in which a special piece of a gene is amplified millions of times over a short period. This method has been of paramount importance in different fields of research and has been applied for different applications. PCR requires thermal cycling, or repeated temperature changes between two or three discrete temperatures to amplify specific nucleic acid target sequences. To achieve such thermal cycling, conventional bench-top thermal cyclers generally use a metal heating block powered by Peltier elements or benefit from forced convection heat transfer. Due to the fact that these methods are time consuming, it seems that design and fabrication of a fast... 

A labeling of a graph is a bijection of edges in graph G to the set {1,2,…, m}. A labeling is antimagic if for any distinct vertices u and v, the sum of the labels on edges incident to u is different from the sum of the labels on edges incident to v. We say a graph is antimagic if it has an antimagic labeling.. In 1990, Hartsfield and Ringel conjectured that every connected graph other than K2 are Antimagic.In this thesis, we show that each graph with at least two degrees can be called Antimagic. We prove this conjecture for regular graphs of odd degree. and then it will be shown that Cartesian graphs have the property of Antimagic Labeling. Finally, we purpose a novel method for k-th powers... 

Penicillin G Acylase is the key enzyme in producing semi-synthetic antibiotics such as Ampicillin and Amoxicillin. In this study, we used E.coli ATCC 11105 in order to produce it. This enzyme was an intracellular one which was produced under suitable conditions. Crude enzyme was released after cell disruption by ultrasonic waves (sonication method) and was partially purified by ammonium sulphate precipitation. Immobilization is investigated at different pHs around the iso-electric pH of Penicillin G Asylase enzyme. Therefore, optimum pH and optimum concentration of ammonium sulphate cuts were determined. Also immobilization process of this enzyme was studied on chitosan polymer, activated by... 

This study aimed to prepare a type of microcapsule that microencapsulates folic acid and iron at the same time and protects these two substances against environmental and gastrointestinal conditions. Simultaneous release of these two nutrients has dual health properties and improves the efficiency of folic acid microencapsulation. In this study, biocomposites were formed containing alginate, pectin, and carboxymethylcellulose, and the microcapsules were synthesized by the ionization of calcium-alginate ions. Biocomposite optimization mixture with 13 experiments using experimental design software, optimal combination design method based on repopulation separator, restoring folic acid... 

Type 1 diabetes, formerly known as insulin-dependent diabetes, may present at any age, but is the most common type of diabetes affecting children and adolescents. People with type 1 diabetes do not produce enough insulin. This type accounts for 5-10% of all types of diabetes. In this type of diabetes, beta cell destruction occurs in the pancreas. In type 1 diabetes, the pancreas does not secrete any insulin; insulin is a hormone that enables the body to convert glucose in food into energy. If sugar in the blood cannot enter the cells, it accumulates in the arteries and results in high blood sugar. High blood sugar over time can have irreversible effects on various parts of the body. Curcumin... 

Beta cells are responsible for secreting insulin to maintain normoglycaemia throughout the individual’s life. Type 1 Diabetes Mellitus (T1DM) is a metabolic disorder characterized by an autoimmune response that promotes the destruction of beta-cells within the pancreatic islets, resulting in lifelong inadequate insulin secretion. Encapsulating beta cells inside a semipermeable membrane to protect encapsulated cells from direct contact with the host immune system, is a new way to treat type 1 diabetes without the need for long-term immunosuppression. . In this case, the semipermeable membrane surrounds the cells and allows oxygen, nutrients, and cell products to penetrate bilaterally while... 

Most natural folate derivatives are highly sensitive to temperature, oxygen and light and their stability depends on food process condition. Alginate and pectin were evaluated for folic acid encapsulation and increasing its stability. By combining them and optimising encapsulation condition the efficiency was enhanced up to 90% . Furthermore, using polymers in combined form caused decrease in folic acid leakage from capsules in acidic condition of stomach. First of all, the time of encapsulation was measured which was 140-180 minutes. In this study the effect of Calcium Chloride concentration on encapsulation was studied. Therefore, two variables were selected which were pectin to algine... 

Vitamin C is one of the essential ingredients for the survival of human beings, animals and plants. This vitamin is an ester that in its structure there is a cyclic ester, an alkene Factor (C = C) and four hydroxyl factor (OH). This vitamin is a white solid, water-soluble and non-toxic that exists in many fruits, especially citrus. Its presence in the diet of human resistance them against infections increases. The main factor causing acidic property in vitamin C is the presence of OH groups attached to the alkene. Various forms of vitamin C exists in pharmaceutical collection of European countries. Since the tablet form because of the many advantages including being economical compared with... 

L-Asparaginase has two major uses. For decades it has been known and used as an antitumor agent. Besides, it has been introduced as a food processing aid in the last trench against acrylamide formation in foods. Here, we have produced extracellular L-Asparaginase from Candida utilis and studied the parameters surrounding its production. Thus, two species of yeast were cross-examined: Saccharomyces cerevisiae (BBRC 30006) and Candida utilis (ATCC 9950). Moreover, the most suitable method for detecting and determining L-Asparaginase activity was investigated and selected for this purpose which is via L-Aspartate determination with Hydroxylamine. Furthermore, six deferent parameters of... 

An antioxidant is a molecule capable of preventing the oxidation of other molecules and neutralizing free radicals. Free radicals are the root cause for many human diseases.Rice bran is one of the most important co-products in the rice milling.In this research antioxidant activity of two Iranian rice bran varieties Fajr and Tarem, extracted by three different solvents (methanol, ethanol and ethyl acetate),determined at different time of extraction by measurement of total phenolic content, free radical scavenging, inhabitation of linoleic acid peroxidation and reducing power. The methanolic extract of Fajr rice bran produced strong results in antioxidant activity. The amount of Total... 

Conjugated linoleic acid (CLA) is a collective term used to describe the mixture of geometric isomers of linoleic acid which has several beneficial biological effects. Considering the use of CLA for medicinal of nutraceutical purposes, an isomer-selective and safe process is required. The introduction of biological reactions to CLA production will solve this problems. Nowadays, CLA is produced through chemical isomerization of linoleic acid which results in by-production of unexpected isomers. From this point of view biotechnology methods and producing microorganisms implementation have gained lots of attention because of not producing unwanted bypass products and also being natural method.... 

With the rapid development of biotechnology, peptide and protein drugs are now playing an increasingly important role in therapeutics. Compared with chemical drugs, peptide and protein drugs have some limitations such as low stability and rapid deactivation. Biodegradable and biocompatible polymeric micro carriers have been shown to have a high potential for the delivery of peptides and proteins. Among these polymers, alginate has been widely investigated as a biomaterial. Alginates are natural polysaccharide polymers isolated from brown seaweed. Bovine serum albumin (BSA) loaded calcium alginate microspheres produced in this study by a modified w/o emulsification method. The influence of... 

β-galactosidase enzyme is immobilized from Kluyveromyces lactis by Microencapsulation method in various compositions of sodium alginate and Carboxymethyl cellulose. Optimum stabilization was gained at 1.85% sodium alginate, 0.9% carboxymethyl cellulose and 2% calcium chloride through applying Surface response methodology. Yield of immobilization and activity was 54.94% and 65.27%. variation of yield of immobilization versus alginate concentration was a quadratic curve with the maximum. When alginate's concentrations is low, the cavities diameter is great, so the enzyme leaks from capsule while immobilizing. At high concentrations of alginate, despite the smaller cavities, immobilization... 

Bacterial cellulose is a kind of cellulose with high purity and Crystallization, which is mainly produced by gram-negative bacteria in aqueous media containing a sugar source.Cellulose produced by this method is in the form of nanofibers and one of its considerable aspects, nowadays, is that this kind of cellulose is used as a drug carrier system for treating various diseases. Azithromycin is used as an antibiotic for the treatment of a wide range of bacterial infections. In this study, cellulose nanofibers were synthesized by gluconacetobacter and its surface was modified using 0.5, 1, and 1.5 mg/ml carboxymethylcellulose solution in sodium acetate buffer. Then, by stabilizing azithromycin... 

In this research performance of microbial fuel cells (MFCs) in continuous flow mode was studied. Different anodic chambers were tested and it was found that granular activated carbons (GACs) produced the highest power density (1228 mW/m3) in comparison with multiple anodes (731 mW/m3), single anode (294 mW/m3) and polymeric packings (40 mW/m3). It was also shown that in a plug-anodic chamber (PAC) the power output is reduced by reducing agitation of anodic volume. Adding more GACs to anodic chamber results in power increase, however by increasing occupied volume from 80% to 100% the power increase was negligible in result of cathodic reactions limitations. Feed flowrate was increased from...