Synthesis of 4-(2-chloroethyl)-2,3-dihydro[1,4]oxazino[2,3-b]quinoline and 4-(2-chloroethyl)2,3-dihydropyrido[2,3-b][1,4]oxazine

The title compounds were synthesized from 3-[bis(2-hydroxyethyl)amino]quinolin-2(1H)-one 11a and 3-[bis(2-hydroxyethyl)amino]pyridin-2(1H)-one 18 respectively. The preparation involved a tandem chlorination/cyclization reaction.     

Optimal allocation of replicas in parallel tempering simulations

We have studied the efficiency of parallel tempering simulations for a variety of systems including a coarse-grained protein, an atomistic model polypeptide, and the Lennard-Jones fluid. A scheme is proposed for the optimal allocation of temperatures in these simulations. The method is compared to the existing empirical approaches used for this purpose. Accuracy associated with the computed thermodynamic quantities such as specific heat is also computed and their dependence on the trial-exchange acceptance rate is reported.     

Trends and Technological Advancements in the Possible Food Applications of Spirulina and Their Health Benefits: A Review

Spirulina is a kind of blue-green algae (BGA) that is multicellular, filamentous, and prokaryotic. It is also known as a cyanobacterium. It is classified within the phylum known as blue-green algae. Despite the fact that it includes a high concentration of nutrients, such as proteins, vitamins, minerals, and fatty acids—in particular, the necessary omega-3 fatty acids and omega-6 fatty acids—the percentage of total fat and cholesterol that can be found in these algae is substantially lower when compared to other food sources. This is the case even if the percentage of total fat that can be found in these algae is also significantly lower. In addition to this, spirulina has a high concentration of bioactive compounds, such as phenols, phycocyanin pigment, and polysaccharides, which all take part in a number of biological activities, such as antioxidant and anti-inflammatory activity. As a result of this, spirulina has found its way into the formulation of a great number of medicinal foods, functional foods, and nutritional supplements. Therefore, this article makes an effort to shed light on spirulina, its nutritional value as a result of its chemical composition, and its applications to some food product formulations, such as dairy products, snacks, cookies, and pasta, that are necessary at an industrial level in the food industry all over the world. In addition, this article supports the idea of incorporating it into the food sector, both from a nutritional and health perspective, as it offers numerous advantages.     

Ageratum conyzoides L. and Its Secondary Metabolites in the Management of Different Fungal Pathogens

Ageratum conyzoides L. (Family—Asteraceae) is an annual aromatic invasive herb, mainly distributed over the tropical and subtropical regions of the world. It owns a reputed history of indigenous remedial uses, including as a wound dressing, an antimicrobial, and mouthwash as well as in treatment of dysentery, diarrhea, skin diseases, etc. In this review, the core idea is to present the antifungal potential of the selected medicinal plant and its secondary metabolites against different fungal pathogens. Additionally, toxicological studies (safety profile) conducted on the amazing plant A. conyzoides L. are discussed for the possible clinical development of this medicinal herb. Articles available from 2000 to 2020 were reviewed in detail to exhibit recent appraisals of the antifungal properties of A. conyzoides. Efforts were aimed at delivering evidences for the medicinal application of A. conyzoides by using globally recognized scientific search engines and databases so that an efficient approach for filling the lacunae in the research and development of antifungal drugs can be adopted. After analyzing the literature, it can be reported that the selected medicinal plant effectively suppressed the growth of numerous fungal species, such as Aspergillus, Alternaria, Candida, Fusarium, Phytophthora, and Pythium, owing to the presence of various secondary metabolites, particularly chromenes, terpenoids, flavonoids and coumarins. The possible mechanism of action of different secondary metabolites of the plant against fungal pathogens is also discussed briefly. However, it was found that only a few studies have been performed to demonstrate the plant’s dosage and safety profile in humans. Considered all together, A. conyzoides extract and its constituents may act as a promising biosource for the development of effective antifungal formulations for clinical use. However, in order to establish safety and efficacy, additional scientific research is required to explore chronic toxicological effects of ageratum, to determine the probability of interactions when used with different herbs, and to identify safe dosage. The particulars presented here not only bridge this gap but also furnish future research strategies for the investigators in microbiology, ethno-pharmacology, and drug discovery.     

Crystal Structure of 3-[1-(4-Methylphenyl)-9,10-dihydro-4-azaphenanthren-3-yl]benzo[f]coumarin

Crystallography Reports - The crystal structure of the title compound is determined by single crystal X-ray structure analysis. The structure was solved by direct method and refined to a final...     

Studies on defect formation in femtosecond laser-irradiated PMMA and PDMS

We report here our results on the spectroscopic and elemental analysis of femtosecond (fs) laser-modified regions in polymers of polymethylmethacrylate (PMMA) and polydimethylsiloxane (PDMS) in the context of defect formation and emission in the visible region. Different physical and chemical models are used to explain the changes in modified regions. We found that the emission intensity, recorded from the fs-modified regions of polymers, decreased over time to a constant value. We also demonstrate that these materials are suitable for the preparation of the microstructures en route for light guiding applications. The fs laser-irradiated regions exhibited paramagnetic behavior as was confirmed from electron spin resonance studies through the formation of peroxide-type free radicals. Raman mapping was performed in the modified regions which consisted of defects and found that the modulations in intensity are predominant in the central portion of the structure compared to edges. Elemental analysis has been performed in the modified regions using field emission scanning electron microscope instrument and energy-dispersive X-ray absorption spectroscopy to estimate the percentage contents of individual elements which resulted in defect formation such as paramagnetic and optical centers.     

Real time correlation filter for optical particle counter

Particle signals are detected by two parallel measuring chains which consist of a detector and analog to digital converter. We have used OPT101 as photodiode and ADS7870 for A/D converter and the output signal from two parallel measuring chains is processed by on line correlation filter. This filter works as real time systems. A correlation algorithm has been applied for this work. The signal to noise ratio has been increased by applying correlation filter. The gain of the filter has been improved by introducing digital signal processing.