Naturally-derived biopolymers: Potential platforms for enzyme immobilization

Review: Catalytic oxidation of cellulose with nitroxyl radicals under aqueous conditions

Most of the past document image watermarking schemes focus on providing same level of integrity and copyright protection for information present in the source document image. However, in a document image the information contents possess various levels of sensitivity. Each level of sensitivity needs different type of protection and this demands multiple watermarking techniques. In this paper, a novel intelligent multiple watermarking techniques are proposed. The sensitivity of the information content of a block is based on the homogeneity and relative energy contribution parameters. Appropriate watermarking scheme is applied based on sensitivity classification of the block. Experiments are conducted exhaustively on documents. Experimental results reveal the accurate identification of the sensitivity of information content in the block. The results reveal that multiple watermarking schemes has reduced the amount of data to be embedded and consequently improved perceptual quality of the watermarked image.

Computer Vision, Graphics, and Image Processing

The hemp plant Cannabis sativa Linn, referring to industrial hemp, is a high-yielding annual industrial crop grown providing fibers from hemp stalk and oil from hemp seeds. Although hemp is a niche crop, hemp production is currently undergoing a renaissance. More than 30 countries grow hemp, with China being the largest hemp producing and exporting country. Europe and Canada are also important actors in the global hemp market. Traditionally, hemp as a fiber plant has been used for the production of apparels, fabrics, papers, cordages and building materials. The hurds, as waste by-product of fiber production, were used for bedding of animals, the seeds for human nutrition, e.g., as flour, and the oil for a wide range of purposes, from cooking to cosmetics. Hemp has also been an important crop throughout human history for medicine. Other more recent applications include materials for insulation and furniture, automotive composites for interior applications and motor vehicle parts, bioplastics, jewelry and fashion sectors, animal feed, animal bedding, and energy and fuel production. Foods containing hemp seed and oil are currently marketed worldwide for both animal and human nutrition. They also find applications in beverages and in neutraceutical products. Hemp oil is also used for cosmetics and personal care items, paints, printing inks, detergents and solvents. It is estimated that the global market for hemp consists of more than 25,000 products. Currently, the construction and insulation sector, paper and textile industries, and food and nutrition domains are the main markets while the cosmetics and automotive sector are growing markets. Innovative applications, e.g., in the medical and therapeutic domains, cosmeceuticals, phytoremediation, acoustic domain, wastewater treatment, biofuels, biopesticides and biotechnology, open new challenges. Hemp is also the object of numerous fundamental studies. This review presents and discusses the traditional and new uses of industrial hemp.

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Applications of hemp in textiles, paper industry, insulation and building materials, horticulture, animal nutrition, food and beverages, nutraceuticals, cosmetics and hygiene, medicine, agrochemistry, energy production and environment: a review

Targeted pre-treatment of hemp bast fibres for optimal performance in biocomposite materials: A review

Hemp fibers are a very interesting natural material for textile and technical applications, but some of these applications require improved and/or specific fiber properties. In order to modify hemp fibers for obtaining high added value products, hemp fibers were oxidized with sodium hypochlorite and a catalytic amount of sodium bromide and 2,2,6,6-tetramethylpiperidine-1-oxy radical (TEMPO), under various conditions. The oxidized hemp fibers were analyzed and characterized in terms of chemical composition (lignin and hemicelluloses) and weight loss, fineness, introduced functional groups, sorption (moisture sorption, water retention values, iodine sorption), and mechanical properties (tenacity and elongation). Applied TEMPO-mediated oxidation has been very efficient for simultaneous removal of noncellulosic substances (reduction of lignin content up to 1.95%) and introduction of surface functional groups, i.e., aldehyde (up to 0.415 mmol/g) and carboxyl groups (up to 0.815 mmol/g). The oxidized hemp fiber...

Influence of TEMPO-Mediated Oxidation on Properties of Hemp Fibers

Cotton fibers containing different amounts of aldehyde and carboxyl groups were prepared by varying TEMPO oxidation conditions and then employed as carriers for trypsin immobilization. Depending on the functional group type present in the oxidized fiber, trypsin was immobilized through the ionic interaction or together with the Schiff’s base formation. The TEMPO oxidation caused changes in the chemical and physical properties of the modified cotton, which were evaluated by determining the aldehyde and carboxyl group content, sorption and electrokinetic properties, and surface morphology of fibers. The trypsin activity was assayed with N-α-benzoyl-dl-arginine p-nitroanilide hydrochloride, and the protein content was determined by the Bradford method. The impact of oxidized fiber functional groups on the amount, activity and stability of the immobilized trypsin was investigated. The cotton fibers oxidized under the most severe conditions (4.84 mmol/g NaClO, 180 min) and having the highest functional groups content (0.79 mmol/g) exhibited the maximum amount of immobilized trypsin of about 6.5 mg/g. However, the immobilized activity and the stability were much higher for the fibers containing both carboxyl and aldehyde groups compared to the corresponding fibers containing only carboxyl groups.

TEMPO-oxidized cotton as a substrate for trypsin immobilization: impact of functional groups on proteolytic activity and stability

In this study, a biologically active fibrous material was designed by immobilizing trypsin on viscose fibers The viscose yarn was first oxidized with sodium periodate to produce aldehyde groups and then employed as a support for subsequent immobilization of trypsin through bovine serum albumin The oxidation by sodium periodate caused changes in the chemical and physical properties of the modified yarn samples, which were evaluated by determining the aldehyde group content, fineness and tensile strength of yarn The viscose fibers oxidized under the most severe conditions (04 % NaIO4, 360 min) exhibited the maximum amount of introduced aldehyde groups (1284 mmol/g), but also the highest decrease in tensile strength The trypsin activity was assayed with N-α-benzoyl-DL-arginine p-nitroanilide hydrochloride, whereas the amount of bound trypsin was determined by Bradford method Trypsin immobilized on oxidized viscose yarn retained 973 and 838 % of the initial activity over 60 days of storage at 4 and 25 °C, respectively, and remained firmly attached to the carrier The potential application of obtained bioactive fibers is in the treatment of wounds

Preparation of cellulosic fibers with biological activity by immobilization of trypsin on periodate oxidized viscose fibers

The objective of this research was to impart antimicrobial properties to hemp fibers by incorporation of silver ions in hemp fibers by chemisorption. Sorption properties of hemp fibers were improved by non-selective oxidation using hydrogen peroxide and potassium permanganate. The optimal conditions for silver ions sorption by hemp fibers were determined by changing sorption conditions: pH value and concentration of aqueous silver nitrate solution, as well as duration of sorption. The maximum sorption capacity of modified hemp fibers was 1.84 mmol of Ag+ ions per gram of fibers. Antimicrobial activity of silver-loaded hemp fibers against different pathogens: Staphylococcus aureus, Escherichia coli, and Candida albicans was evaluated in vitro. Obtained silver-loaded hemp fibers show antimicrobial activity against tested pathogens.

Preparation and characterization of silver-loaded hemp fibers with antimicrobial activity

In this paper, we present the construction of a reliable and inexpensive pH stat device, by using open-source "OpenPhControl" software, inexpensive hardware (a peristaltic and a syringe pump, Arduino, a step motor…), readily available laboratory devices: a pH meter, a computer, a webcam, and some 3D printed parts. We provide a methodology for the design, development and test results of each part of the device, as well as of the entire system. In addition to dosing reagents by means of a low-cost peristaltic pump, we also present carefully controlled dosing of reagents by an open-source syringe pump. The upgrading of the basic open-source syringe pump is given in terms of pump control and application of a larger syringe. In addition to the basic functions of pH stat, i.e. pH value measurement and maintenance, an improvement allowing the device to be used for potentiometric titration has been made as well. We have demonstrated the device's utility when applied for cellulose fibers oxidation with 2,2,6,6-tetramethylpiperidine-1-oxyl radical, i.e. for TEMPO-mediated oxidation. In support of this, we present the results obtained for the oxidation kinetics, the consumption of added reagent and experimental repeatability. Considering that the open-source scientific tools are available to everyone, and that researchers can construct and adjust the device according to their needs, as well as, that the total cost of the open-source pH stat device, excluding the existing laboratory equipment (pH meter, computer and glossary) was less than 150 EUR, we believe that, at a small fraction of the cost of available commercial offers, our open-source pH stat can significantly improve experimental work where the use of pH stat is necessary.

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Jovana Milanovic

Papers

Influence of TEMPO-Mediated Oxidation on Properties of Hemp Fibers

TEMPO-oxidized cotton as a substrate for trypsin immobilization: impact of functional groups on proteolytic activity and stability

Preparation of cellulosic fibers with biological activity by immobilization of trypsin on periodate oxidized viscose fibers

Preparation and characterization of silver-loaded hemp fibers with antimicrobial activity

"Do-It-Yourself" reliable pH-stat device by using open-source software, inexpensive hardware and available laboratory equipment.