Simultaneous TR-SPIV and CH* chemiluminescence during precursor to LBO in a lean premixed swirl dump combustor

Blowout process in premixed swirl dump combustors is known to have temporary partial extinction followed by re-ignition events as precursors. This re-ignition process is investigated using high-speed CH* chemiluminescence and simultaneous TR-SPIV. It was found that during the extinction phase, the flame split into two zones, causing fresh mixture to enter the inner recirculation zone. The sudden loss of heat release causes the flow field to change such that the stagnation point moves further downstream, causing high negative velocity paths in the flow. The flame that was convected downstream, now uses these negative velocity paths to consume the fresh mixture that entered the IRZ. This is the re-ignition phase of the precursor event.     

In vivo gastroprotective effect of xyloccensin-E and xyloccensin-I from Xylocarpus molluccensis in rats

Anti-ulcer activities of xyloccensin-E and xyloccensin-I were investigated in various ulcer models in Sprague-Dawley rats. The effects and the mechanism of action of both compounds for anti-secretory and cytoprotective activities were also studied. Both these active molecules improved the depleted levels of mucin and consequently inhibited the formation of erosions in a pyloric ligated ulcer model. Furthermore, xyloccensin-E and xyloccensin-I inhibited H⁺K⁺-ATPase activity in vitro confirming their anti-secretory activity. In conclusion, xyloccensin-E and xyloccensin-I were found to possess anti-ulcerogenic activity which might be due to their anti-secretory activity and subsequent strengthening of the defensive mechanism.     

Chiral benzimidazoles and their applications in stereodiscrimination processes

Chiral aspects of benzimidazoles have been over-shadowed for a long time due to the large number of reports on benzimidazoles in the medical field in numerous categories of therapeutic agents. The vigorous research activity in chiral applications of benzimidazole derivatives started after bifunctional benzimidazoles made their appearance especially in the last 2–3 decades. Thus, chiral benzimidazoles form a comparatively young branch of chiral chemistry. The presence of pyridine and pyrrole type of nitrogens along with the fused benzene ring confer on this class of molecules, special properties including useful nucleophilicity, hydrogen bonding ability and a rigid backbone, all of which play decisive roles in proven chiral applications. The present review aims to cover the synthetic routes to access chiral benzimidazoles and their applications in a plethora of chiral fields including enantioselective organocatalysis, metal-based catalysis, asymmetric transformations involving benzimidazole-N-heterocyclic carbenes, kinetic resolution, benzimidazole-based macrocyclic hosts in chiral supramolecular chemistry and other miscellaneous chiral applications.     

Ruthenium‐Catalyzed Cascade C?H Functionalization of Phenylacetophenones

Three orthogonal cascade C H functionalization processes are described, based on ruthenium‐catalyzed C H alkenylation. 1‐Indanones, indeno indenes, and indeno furanones were accessed through cascade pathways by using arylacetophenones as substrates under conditions of catalytic [{Ru(p‐cymene)Cl₂}₂] and stoichiometric Cu(OAc)₂. Each transformation uses C H functionalization methods to form C C bonds sequentially, with the indeno furanone synthesis featuring a C O bond formation as the terminating step. This work demonstrates the power of ruthenium‐catalyzed alkenylation as a platform reaction to develop more complex transformations, with multiple C H functionalization steps taking place in a single operation to access novel carbocyclic structures.     

Magnesium ferrichromate nanoparticles: an efficient and recyclable catalyst in the synthesis of pyrano[2,3-c]pyrazole derivatives

Research on Chemical Intermediates - Magnetically separable magnesium ferrichromate nanoparticles (MgFeCrO4 NPs) were synthesized by aqueous combustion synthesis (ACS) using glycine as the fuel....     

Thermal degradation kinetics study and thermal cracking of waste cooking oil for biofuel production

Thermal cracking of waste cooking oil (WCO) for production of liquid fuel has gained special interest due to the growing demand of renewable fuel, depleting fossil fuel reserves and environmental issues. In the present work, thermal cracking of WCO to produce liquid hydrocarbon fuels without any preprocessing has been studied. Moreover, non-isothermal kinetics of WCO using thermogravimetric analysis (TGA) has been studied under an inert atmosphere at various heating rates. According to TGA result, active thermal decomposition of WCO was found to be between 318 and 500 °C. Furthermore, the temperature at which the maximum mass loss rate attained was shifted to higher values as the heating rates increased from 10 to 50 °C min^?1 and the values were found to be approximately similar to that of R ₅₀. Besides, model-free iso-conversion kinetic methods such as Friedman (FM), Kissinger–Akahira–Sunose (KAS) and Flynn–Wall–Ozawa (FWO) were used to determine the activation energies of WCO degradation. The average activation energy for the thermal degradation of WCO was found to be 243.7, 211.23 and 222 kJ mol^?1 for FM, KAS and FWO kinetic methods, respectively. Additionally, the cracking of WCO was studied in a semi-batch reactor under an inert atmosphere and the influences of cracking temperature, time and heating rates on product distribution were investigated. From the reaction, an optimum yield of 72 mass% was obtained at a temperature of 475 °C, time of 180 min and a heating rate of 10 °C min^?1. The physicochemical properties studied were in accordance with ASTM standards.     

Effect of headgroup on DNA-cationic surfactant interactions

The interaction behavior of DNA with different types of hydroxylated cationic surfactants has been studied. Attention was directed to how the introduction of hydroxyl substituents at the headgroup of the cationic surfactants affects the compaction of DNA. The DNA-cationic surfactant interaction was investigated at different charge ratios by several methods like UV melting, ethidium bromide exclusion, and gel electrophoresis. Studies show that there is a discrete transition in the DNA chain from extended coils (free chain) to a compact form and that this transition does not depend substantially on the architecture of the headgroup. However, the accessibility of DNA to ethidium bromide is preserved to a significantly larger extent for the more hydrophilic surfactants. This was discussed in terms of surfactant packing. Observations are interpreted to reflect that the surfactants with more substituents have a larger headgroup and therefore form smaller micellar aggregates; these higher curvature aggregates lead to a less efficient, "patch-like" coverage of DNA. The more hydrophilic surfactants also presented a significantly lower cytotoxicity, which is important for biotechnological applications.     

Rapid densitometric method for simultaneous analysis of umbelliferone, psoralen, and eugenol in herbal raw materials using HPTLC

The term 'phenolics' refers to a vast array of biologically active compounds ubiquitous in plants, many of which have been used in traditional medicine for thousands of years. Umbelliferone, psoralen, and eugenol are widely occurring phenolic compounds of plant origin, for which many biological activities against chronic diseases have been reported. A simple HPTLC method has been developed for the simultaneous quantification of umbelliferone, psoralen, and eugenol. These three compounds were quantified in the dried fruit pulp of Aegle marmelos and in the fruit of Trachyspermum ammi and Foeniculam vulgare. The technique enables rapid and sensitive simultaneous analysis in different samples. The method was validated for precision, repeatability, and accuracy in accordance with ICH guidelines. The accuracy of the method was checked by a recovery study conducted at three different levels and the average percentage recovery was found to be 98.88% for umbelliferone, 100.104% for psoralen, and 99.33% for eugenol. The proposed HPTLC method for the simultaneous quantification of umbelliferone, psoralen, and eugenol was found to be simple, precise, specific, sensitive, and accurate. It can be used for routine quality control of herbal raw materials as well as formulations containing any or all of these compounds.