A study of the behavior of cadmium and zinc microquantities in sorption and coprecipitation processes in tetrahydrofuran solutions

The sorption of ¹⁰⁹Cd and ⁶⁵Zn microquantities with NaX and NaA zeolites in the presence of divalent lanthanides (Ln²⁺) (Ln=Tm, Dy, and Nd) from tetrahydrofuran (THF) solutions was studied. It was found that in contrast to ¹³⁷Cs⁺, ¹⁰⁹Cd and ⁶⁵Zn, as well as ⁸⁵Sr²⁺ microquantities were sorbed by zeolites very poorly: ∼99% of the species remained in solution. The distribution coefficients (K _d ) of ¹⁰⁹Cd and ⁶⁵Zn were ∼0.3 and ∼0.4 ml/g, respectively. When Tm²⁺ was used as a reducer, it partially oxidized in solution to Tm³⁺ to form precipitates of the composition TmI₃·3THF. A study of the co-crystallization of ¹⁰⁹Cd and ⁶⁵Zn, as well as ⁸⁵Sr²⁺ microquantities with the TmI₃·3THF solid phase in the presence of Tm²⁺ from THF solutions showed that in contrast to ⁸⁵Sr²⁺, ¹⁰⁹Cd and ⁶⁵Zn microquantities co-crystallized with the TmI₃·3THF solid phase. The co-crystallization coefficients (D) for ¹⁰⁹Cd and ⁶⁵Zn depended on the ratio Tm³⁺/Tm²⁺ in solution and increased with its increasing. The assumption was made that in the presence of Tm²⁺, ¹⁰⁹Cd²⁺ and ⁶⁵Zn²⁺ form M⁺ ions, which quickly react with M²⁺ ions to form dimers of the composition M₂ ³⁺ (M=Cd and Zn).     

An optimal algorithm for the minimum-width cubic shell problem

Given a set of n points in ${\mathbb{R}}^3$, the minimum-width cubic shell problem asks to find a thinnest cubic shell that encloses the input points, where a cubic shell refers to as a closed volume between two concentric axis-aligned cubes. In this paper, we improve the previous $O(n{\log }^{2}n)$-time algorithm presented in Bae (2019) [6] to $O(n\log n)$ worst-case time. This is the first optimal-time algorithm to the problem.     

Polyphenolic characterization and evaluation of multimode antioxidant,cytotoxic, biocompatibility and antimicrobial potential of selected ethno-medicinal plant extracts

IntroductionScientific evidence about biological profile of natural products can support their traditional uses. The current work was aimed to assess phytochemical and biological profile of nine medicinal plants collected from Herbalists.MethodsExtracts prepared in different solvents were subjected to phytochemical, antioxidant, enzyme inhibitory, cytotoxic, and antimicrobial activities. Reverse phase-high performance liquid chromatography (RP-HPLC) analysis was performed for the quantification of polyphenols.ResultsResults showed methanol extract (M) being potent as compared to others. Gentian lutea M showed maximum extract recovery (15.00 ± 0.11 % w/w) and TFC (30.82 ± 0.21 μg QE/mg extract). Nigella sativa M displayed highest TPC (44.99 ± 0.43 μg GAE/mg extract) and TAC (334.72 ± 0.35 μg AAE/ mg extract). Results showed noteworthy quantities of vanillic acid, rutin, kaempferol, emodin in ethyl acetate (EA) and methanol (M) extracts of plants assessed by RP-HPLC. Gentisic acid was highest (11.75 µg/mg extract) in T. arjuna M extract. Similarly, maximum %FRSA (82.28 ± 0.03 %) and TRP (160.40 ± 0.38 μg AAE/ mg extract) were depicted by Terminalia chebula and Chamomilla recutita, respectively. Moreover, Mentha longifolia and G. lutea M demonstrated noteworthy (p < 0.05) antibacterial activity against Staphylococcus aureus (14 ± 0.7 mm) and Klebsiella pneumoniae (12 ± 0.3 mm), respectively. Curcuma amada, C. recutita, Murraya koenigii and G. lutea M had significant α-glucosidase activity. Another good solvent for extraction was ethyl acetate (EA), whose extracts were secondary to methanol in producing significant biological profile. For example, EA of N. sativa (TPC: 1.46 ± 0.45 µg GAE/ mg extract), G. lutea (TRP: 160.33 ± 0.52 μg AAE/mg extract: ZOI of 12 ± 0.5 mm in K. pneumoniae) and Mormodica charantia (α-amylase inhibition: 39.5 ± 0.10 %) showed significant bioactivities. All extracts displayed mild antifungal protein kinase inhibition activities and were significantly (greater than80 %: p < 0.05) cytotoxic to brine shrimps with negligible hemolytic activity.ConclusionBriefly, variable polarity solvent extracts of studied plants will be processed for isolation of antioxidant, cytotoxic, carbohydrate enzyme inhibitory and antibacterial compounds.     

Investigation of cavitation noise using Eulerian-Lagrangian multiscale modeling

We have employed the large eddy simulation (LES) approach to investigate the cavitation noise characteristics of an unsteady cavitating flow around a NACA66 (National Advisory Committee for Aeronautics) hydrofoil by employing an Eulerian-Lagrangian based multiscale cavitation model. A volume of fluid (VOF) method simulates the large cavity, whereas a Lagrangian discrete bubble model (DBM) tracks the small bubbles. Meanwhile, noise is determined using the Ffowcs Williams-Hawkings equation (FW-H). Eulerian-Lagrangian analysis has shown that, in comparison to VOF, it is more effective in revealing microscopic characteristics of unsteady cavitating flows, including microscale bubbles, that are unresolvable around the cloud cavity, and their impact on the flow field. It is also evident that its evolution of cavitation features on the hydrofoil is more consistent with the experimental observations. The frequency of the maximum sound pressure level corresponds to the frequency of the main cavity shedding for the noise characteristics. Using the Eulerian-Lagrangian method to predict the noise signal, results show that the cavitation noise, generated by discrete bubbles due to their collapse, is mainly composed of high-frequency signals. In addition, the frequency of cavitation noise induced by discrete microbubbles is around 10 kHz. A typical characteristic of cavitation noise, including two intense pulses during the collapsing of the cloud cavity, is described, as well as the mechanisms that underlie these phenomena. The findings of this work provide for a fundamental understanding of cavitation and serve as a valuable reference for the design and intensification of hydrodynamic cavitation reactors.     

Polypept(o)ide-based bactericides: weapons against antibiotic-resistant bacterial infections

Emerging antibiotic resistance in bacterial pathogens has necessitated the development of alternative ‘outside of the box’ antimicrobial therapeutics. Polypept(o)ide-based bactericides with chemical structures mimicking antimicrobial host defense peptides have emerged as promising candidates for treating antibiotic-resistant and recurring infections. This review summarizes the recent advances in membrane-active polypept(o)ide-based bactericides in the treatment of antibiotic-resistant bacterial infections associated with the physical disruption of bacterial cell walls/cell membranes. Among these polypept(o)ide-based bactericides, nonantibiotic treatment strategies are employed to combat lethal bacterial strains resulting from acquired antibiotic resistance and biofilm formation, featuring the capacity to evade acquired antibiotic resistance-related mechanisms and to alleviate the emergence of drug resistance. Emphasis will focus on the typical polypept(o)ides with diverse molecular conformations (e.g., linear, brush-like, and star-shaped) and various chemical structures of monomers (e.g., α-amino acid, β-amino acid, and N-substituted glycine) that are central to the performance of antimicrobial polypept(o)ides. Finally, a brief discussion of the key challenges and prospects of polypept(o)ide-based bactericides is presented.     

Recent studies on advance spectroscopic techniques for the identification of microorganisms: A review

The continuous development of resistance to antibiotic drugs by microorganisms causes high mortality and morbidity. Pathogens with distinct features and biochemical abilities make them destructive to human health. Therefore, early identification of the pathogen is of substantial importance for quick ailments and healthcare outcomes. Several phenotype methods are used for the identification and resistance determination but most of the conventional procedures are time-consuming, costly, and give qualitative results. Recently, great focus has been made on the utilization of advanced techniques for microbial identification. This review is focused on the research studies performed in the last five years for the identification of microorganisms particularly, bacteria using advanced spectroscopic techniques including mass spectrometry (MS), infrared (IR) spectroscopy, Raman spectroscopy (RS), and nuclear magnetic resonance (NMR) spectroscopy. Among all the techniques, MS techniques, particularly MALDI-TOF/MS have been widely utilized for microbial identification. A total of 44 bacteria i.e., 6 Staphylococcus spp., 3 Enterococcus spp., 6 Bacillus spp., 4 Streptococcus spp., 6 Salmonella spp., and one from each genus including Escherichia, Acinetobacter, Pseudomonas, Proteus, Clostridioides, Candida, Brucella, Burkholderia, Francisella, Yersinia, Moraxella, Vibrio, Shigella, Serratia, Citrobacter, and Haemophilus (spp.) were discussed in the review for their identification using the above-mentioned techniques. Among all the identified microorganisms, 21% of studies have been conducted for the identification of E. coli, 14% for S. aureus followed by 37% for other microorganisms.     

Biological activities from andiroba (Carapa guianensis Aublet.) and its biotechnological applications: A systematic review

Carapa guianensis is a tree from Meliaceae family traditionally known as andiroba that has a wide range of biological properties, including therapeutic effects, antioxidant activities, insecticidal and repellent effects that can be used in biotechnological approaches to medicine, agriculture, and cosmetic products. Therefore, we aim to explore the biological activities exhibited by this species and their respective biotechnological applications of interest. For this, a systematic review was carried out following the PRISMA guidelines dated from 1993 to 2022 through the Scopus, Web of Science and Agricultural Research Database (Base de Dados da Pesquisa Agropecuária - BDPA), screened for biological activity/bioactive compounds. A total of 129 studies were included in the PRISMA flow analysis. Biological properties and major bioactive compounds, as well as biotechnological approaches could be identified. The biological activity from C. guianensis could be observed in different vegetative parts through diverse methods of extractions. These activities are mainly due to the unsaturated fatty acids and bioactive compounds, such as the limonoids and a small fraction of phenolic compounds. Gedunin-type limonoids, like gedunin and its derivatives, represent the class of compounds that show the highest bioactivities in different applications.