Agro-Waste Generated Pd/CAP-Ash Catalyzed Ligand-Free Approach for Suzuki–Miyaura Coupling Reaction

Catalysis Letters - We converted agro-waste Custard Apple Peels (CAP) to ash via thermal treatment, on which Pd(OAc)2 was immobilized easily that produced a low-cost, highly efficient Pd/CAP-ash...     

Privacy-preserving iris authentication using fully homomorphic encryption

Multimedia Tools and Applications - Rapid advancement in technology has led to the use of biometric authentication in every field. In particular, from the past few years, iris recognition systems...     

A new controller for boost dc–dc converters based on a novel sliding surface

ABSTRACT

In this paper, two control schemes for boost converters affected by uncertainties in input voltage and load are proposed. The boost converter dynamics is redefined in terms of new state variables to facilitate the use of a disturbance observer that can estimate matched and unmatched disturbances. A sliding surface, which is new in the context of boost converters, is proposed to enable tracking and regulation of output voltage without requiring measurement of input voltage and load current. The stability of the overall system including the disturbance observer, the sliding variable and the output is proved. The performance of the schemes is assessed for regulation of output voltage and tracking of reference voltage by simulation as well as experimentation in which various types of uncertainties and various types of reference voltages are considered.     

Photoactive Earth‐Abundant Iron Pyrite Catalysts for Electrocatalytic Nitrogen Reduction Reaction

The generation of ammonia, hydrogen production, and nitrogen purification are considered as energy intensive processes accompanied with large amounts of CO₂ emission. An electrochemical method assisted by photoenergy is widely utilized for the chemical energy conversion. In this work, earth‐abundant iron pyrite (FeS₂) nanocrystals grown on carbon fiber paper (FeS₂/CFP) are found to be an electrochemical and photoactive catalyst for nitrogen reduction reaction under ambient temperature and pressure. The electrochemical results reveal that FeS₂/CFP achieves a high Faradaic efficiency (FE) of ≈14.14% and NH₃ yield rate of ≈0.096 µg min^?1 at ?0.6 V versus RHE electrode in 0.25 m LiClO₄. During the electrochemical catalytic reaction, the crystal structure of FeS₂/CFP remains in the cubic pyrite phase, as analyzed by in situ X‐ray diffraction measurements. With near‐infrared laser irradiation (808 nm), the NH₃ yield rate of the FeS₂/CFP catalyst can be slightly improved to 0.1 µg min^?1 with high FE of 14.57%. Furthermore, density functional theory calculations demonstrate that the N₂ molecule has strong chemical adsorption energy on the iron atom of FeS₂. Overall, iron pyrite‐based materials have proven to be a potential electrocatalyst with photoactive behavior for ammonia production in practical applications.     

Optimized mobility management protocol for the IoT based WBAN with an enhanced security

Wireless Networks - Today, Wireless Sensor Network (WSN) is widely used for general purposes. With the propagation of the Internet of Things (IoT), security issues arise wherever the healthcare...     

Hydrotreatment of jatropha oil over noble metal catalysts

Jatropha oil is a promising nonedible feedstock for producing renewable diesel. In this work, the hydrotreatment processing of jatropha oil was investigated. Instead of using conventional alumina-supported Co–Mo, Ni–Mo, and Ni–W catalysts that need sulfidation pretreatment, noble metals such as Pd and Ru were chosen. Trials were performed in an isothermal trickle-bed reactor and the reaction conditions were as follows: temperature 603–663?K, weight hourly space velocity (WHSV) 1 to 4/h, pressure 1.5–3?MPa, and H₂/oil ratio 200–800 (v/v). Yield of n-C₁₅ to n-C₁₈ hydrocarbons was maximized (70.3 and 43.8% for Pd/Al₂O₃ and Ru/Al₂O₃, respectively) at the following conditions: T?=?663 K, WHSV?=?2/h, P?=?3?MPa, and H₂/oil ratio?=?600 (v/v). Since Ru favored cracking reactions to a larger extent than Pd, the yield of C₁₅ to C₁₈ hydrocarbons over Ru/Al₂O₃ was lowered. Using simple first-order plots for oil conversion, activation energies for the hydrotreating process over Pd/Al₂O₃ and Ru/Al₂O₃ were found and they were equal to 109 and 121?kJ/mol, correspondingly.     

Cellular Disulfide Bond Formation in Bioactive Peptides and Proteins

Bioactive peptides play important roles in metabolic regulation and modulation and many are used as therapeutics. These peptides often possess disulfide bonds, which are important for their structure, function and stability. A systematic network of enzymes—a disulfide bond generating enzyme, a disulfide bond donor enzyme and a redox cofactor—that function inside the cell dictates the formation and maintenance of disulfide bonds. The main pathways that catalyze disulfide bond formation in peptides and proteins in prokaryotes and eukaryotes are remarkably similar and share several mechanistic features. This review summarizes the formation of disulfide bonds in peptides and proteins by cellular and recombinant machinery.