One pot synthesis of pyrrolidines type 3,7-diazabicyclo [3.3.0] octane and biological activity

Pyrrolidines type 2,4-disubstituted (alkyl, aryl or heteroaryl)-6,8-dioxo-3,7-diazabicyclo [3.3.0] octanes (8a-d) were successfully synthesized by an efficient one pot 1,3-dipolar cycloaddition of azomethine ylides (in situ generated from the reaction of aromatic aldehydes and methyl ester of alpha-amino acids) with dipolarophile (N-phenylmaleimide). The reaction of compounds 8a-d with hydrazine in ethanol at room temperature took place under nucleophilic substitution which furnished 5-amino-4,6-dioxo-octahydropyrrolo [3,4-b] pyrrole-3-carboxylic acid phenylamides (12a-d). Structures of the products were confirmed by IR and 1H NMR. The compounds (8b and 12a) were evaluated for antimicrobial (agar dilution method) and antioxidative (DPPH; 2,2-diphenyl-1-picrylhydrazyl and SOD; superoxide dismutase assays) activities. The results showed that at concentrations of 4-256 µg/mL, the tested compounds exhibited non-significant antimicrobial growth, whereas the 12a at 200 µg/mL began to exert some antioxidative activity

The Future of Food Preservation: Active Packaging with Controlled Release Systems

This report provides an overview of active packaging with a focus on controlled release packaging (CRP) technologies, which have been developed to improve the shelf life of food products. Active packaging systems incorporate various functional components such as antimicrobial agents or oxygen scavengers into package material to maintain product quality during storage. CRP technology involves encapsulating bioactive compounds within a carrier matrix that can be released in a controlled manner over time. The paper compares these two promising technologies and highlights their advantages for extending shelf life while maintaining product quality. While active packaging is more suitable for short-term preservation due to non-controllable active agent release, CRP has potential applications in long-term preservation due to its ability to provide sustained release of bioactive compounds. Future prospects include developing a blend of CRP and intelligent food packaging. However, challenges remain including the sustainable release rate of the active agents from the packaging into the headspace or food surface. Overall, this review provides insights into the current state-of-the-art research on CRP technologies while highlighting future directions for improving food safety through innovative approaches aimed at preserving freshness while minimizing waste generation from expired products

Performance Analysis of Integral Process of Bio-Oil Production, Bio-Oil Upgrading, and Hydrogen Production from Sewage Sludge

This research investigated the production of bio-oil through the hydrothermal liquefaction (HTL) process using sewage sludge from wastewater, along with the hydrotreating of the bio-oil. The simulation process began with a wastewater flow rate of 460 tonnes/day, where the feedstock was divided into two streams. The first stream underwent the HTL process, while the other was directed towards hydrogen production. The resulting products included gaseous products, crude bio-oil, and heavy liquid. The crude bio-oil was further upgraded by introducing hydrogen, which was obtained through gasification and purified by gas separation using a palladium membrane. The primary product mainly comprised alkane, with a carbon content of 85.89% and hydrogen content of 14.11%. For the purification of gasoline, kerosene, diesel, and fuel oil, a fractionation distillation tower arrangement was designed. In addition, Additionally, the gaseous products underwent fractionation distillation to obtain 98% nitrogen and 99.9% liquid carbon dioxide. Considering the carbon footprint, it was observed that the bio-oil production process resulted in the highest greenhouse gas (GHG) emissions

Climate-Conscious Food Preserving Technologies for Food Waste Prevention

Global food production is responsible for around 26% of greenhouse gas emissions caused by human activities. Notably, 6% of these emissions are caused by unconsumed food. Both traditional and current climate-conscious technologies for food preservatives that assure food waste reduction are discussed. This review investigates the potential of smart packaging biosensors and natural antimicrobial agents in fostering environmentally friendly, cutting-edge food systems. Specifically, it highlights the studies that explore the use of natural antimicrobial agents of calcined corals in active packaging systems for storing milk. The finding revealed that this method had a significant impact on maximizing the shelf life of fresh food. Furthermore, this review discusses the concept of smart packaging of food, focusing on biopolymer-based nanocomposites and biosensors, which have gained increasing attention in the food industry due to concerns about food safety and quality. The review also examines the efforts of the United Arab Emirates (UAE) to combat food waste through the initiatives such as UAE Food Bank, Winnow, and Ne’ma which is the national food loss and waste project. These technologies and practices have the potential to guarantee food safety, preserve quality, and reduce waste, but there are still issues with cost, biocompatibility, and consumer acceptance

X=Y–ZH compounds as potential 1,3-dipoles. Part 64: Synthesis of highly substituted conformationally restricted and spiro nitropyrrolidines via Ag(I) catalysed azomethine ylide cycloadditions

1,3-Dipolar reactions of imines of both acyclic and cyclic α-amino esters with a range of nitroolefins using a combination of AgOAc or Ag2O with NEt3 are described. In most cases the reactions were highly regio- and stereospecific and endo-cycloadducts were obtained in good yield. However, in a few cases the initially formed cycloadducts underwent base catalysed epimerisation. The stereochemistry of the cycloadducts was assigned from NOE data and established unequivocally in several cases by X-ray crystallography

Development of magnetic floc technology for water treatment

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Data security for multimedia communications

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Data Security for Multimedia Communications.

Nowadays, many cryptographic algorithms have been implemented for security purposes in communication systems. The problem of security has become an important issue in many applications, especially in multimedia applications. In this thesis, the security-related problems of particular multimedia applications are addressed and various cryptographic algorithms are then implemented in known or adapted procedures to solve such problems. The range of issues considered can be classified as follows: Firstly, the problem of certifying the integrity of images from digital cameras such as for video surveillance is addressed and a scheme designed for this purpose is presented. Secondly, the problem of user authentication in one-way broadcast applications such as pay-TV service is indicated and a key distribution scheme based on the smart card and set top box combination technique is designed to solve such a problem. Thirdly, the problem of the right of privacy in communications between two parties is discussed and a scheme based on cascading algorithms is then used as a solution. Fourthly, the problem of encrypting a large amount of multimedia data such as a video stream is addressed and a low-complexity encryption method using block ciphers is designed to cope with this kind of data. Finally, the problem of secure distribution of copyright data is studied and two different approaches are then proposed. The first approach is based on the idea that the output from the watermarking scheme should be in encrypted form. The second approach is based on the idea of watermarking an encrypted copy. All the proposed schemes have been published in some forms and therefore subjected to outside review of their security