Definitive Screening Design and Artificial Neural Network for Modeling a Rapid Biodegradation of Date Palm Fronds by a New Trichoderma sp. PWN6 into Citric Acid

Generally, the bioconversion of lignocellulolytics into a new biomolecule is carried out through two or more steps. The current study used one-step bioprocessing of date palm fronds (DPF) into citric acid as a natural product, using a pioneer strain of Trichoderma harzianum (PWN6) that has been selected from six tested isolates based on the highest organic acid (OA) productivity (195.41 µmol/g), with the lowest amount of the released glucose. Trichoderma sp. PWN6 was morphologically and molecularly identified, and the GenBank accession number was MW78912.1. Both definitive screening design (DSD) and artificial neural network (ANN) were applied, for the first time, for modeling the bioconversion process of DPF. Although both models are capable of making accurate predictions, the ANN model outperforms the DSD model in terms of OA production, as ANN is characterized by a higher value of R² (0.963) and validation R² (0.967), and lower values of the RMSE (13.44), MDA (11.06), and SSE (9749.5). Citric acid was the only identified OA as was confirmed by GC-MS and UPLC, with a total of 1.5%. In conclusion, DPF together with T. harzianum PWN6 is considered an excellent new combination for citric acid biosynthesis, after modeling with artificial intelligence procedure.     

Simultaneous convection and radiation in flow between two parallel plates

A numerical solution is described for simultaneous forced convection and radiation in flow between two parallel plates forming ahannel. The front plate is transparent to thermal radiation while the back one is thermally insulated. Analyses for both flow and heat are presented for the case of a non-emitting ‘blackened’ fluid. The governing equations of the stream function and the temperature together with their boundary conditions are presented in non-dimensional expressions. The solution is found to depend on eight dimensionless parameters, namely the ratio of the height of the channel to the distance between the plates, the initial dimensionless temperature, the optical thickness, the absorptivities of both plates, the Reynolds number, the Prandtl number and the heat transfer coefficient from the front plate to the surroundings. The numerical solution is obtained using a finite-difference technique. A study has been made of the effect of the initial temperature of the flow at the channel inlet, the dimensionless loss coefficient from the front plate, the absorptivity of the back plate and the optical thickness, on the temperature distribution in the channel, the heat collection efficiency and the average temperature rise in the channel. Results showed that increasing the optical thickness increases the temperature of the front plate and decreases the temperature of the back plate. Also, increasing the optical thickness increases the efficiency of heat collection, which reaches its maximum asymptotic value at an optical thickness of about 1.5. Moreover, the location of the maximum temperature is found to depend on both the optical thickness and the dimensionless heat loss coefficient from the front plate.     

Parametric study on fluidized bed thermal storage

In the present work, the numerical model developed earlier by the same authors [5] is refined and recast in non-dimensional form. The refined model is calibrated with recent experiments at different bed air-inlet temperatures. Excellent agreement between the numerical results and experiments is obtained. The refined model is then used to conduct an extensive parametric study. The objectives of the parametric study are: (i) to determine the effect of the non-dimensional parameters (α₂, α₃ and α₄) on the bed performance; (ii) to indicate the conditions required for favourable bed operation, and (iii) to compare the fluidized-bed performance with a small-particle packed bed performance. The numerical results are presented as time-histories of average bed temperature ( \(\bar \theta _b \) ) and bed efficiency(η). The performance histories are given for different value of each parameter (α₂, α₃, and α₄). The study shows that the fluidized bed behaves favourably for α₂ < 10, α₃> 30 and α₄ < 10. Moreover, it was concluded that the small particle packed bed, in general, offers better performance behaviour over a fluidized bed having the same bed size and heat input.     

Numerical study of evaporation-condensation in a vertical diffusion gap

The present work deals with mass transfer between a vertical falling film over a heated plate and a condensing film over a parallel cooled plate in a diffusion gap. This is typically the case of the distillation process in a diffusion still. The governing equations for mass, momentum, and energy are considered for the evaporating film, the diffusion gap, and the condensing film, together with the boundary and interfacial conditions. The local similar technique is used to solve the problem numerically and to get the velocity and temperature distributions in the gap. A comprehensive analysis of the effect of evaporating temperature, condensing temperature, and diffusion gap width over the diffusion mass flow rate and evaporation heat transfer coefficient are carried out. Performance charts of air and helium diffusion gaps are given. Additionally, the analytical results are experimentally validated.     

Combination and tricombination therapy to destabilize the structural integrity of COVID-19 by some bioactive compounds with antiviral drugs: insights from molecular docking study

Structural Chemistry - Recently, the SARS-CoV-2 (COVID-19) pandemic virus has been spreading throughout the world. Until now, no certified drugs have been discovered to efficiently inhibit the...     

Molecularly Imprinted Poly-o-phenylenediamine Electrochemical Sensor for Entacapone

We have developed a molecularly imprinted polymer (MIP) electrochemical sensor for entacapone (ETC) based on an electropolymerised polyphenylenediamine (Po-PD) on a glassy carbon electrode (GCE) surface. The direct electropolymerisation of the o-phenylenediamine monomer (o-PD) was carried out with ETC as a template. The steps of electropolymerization process, template removal and binding of the analyte were tested by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) using [Fe(CN)₆]³⁻/[Fe(CN)₆]^{4 −} as a redox probe. The operation of the sensor has been investigated by differential pulse voltammetry (DPV). Under optimal experimental conditions, the response of the DPV was linearly proportional to the ETC concentration between 1.0×10⁻⁷ and 5.0×10⁻⁶ M ETC with a limit of detection (LOD) of 5.0×10⁻⁸ M. The developed sensor had excellent selectivity without detectable cross-reactivity for levodopa and carbidopa. The MIP sensor was successfully used to detect ETC in spiked human serum samples.     

Mixed Organometallic–Organic Hybrid Assemblies Based on the Diarsene Complex [Cp2Mo2(CO)4(μ,η2-As2)], AgI Salts and N-Donor Organic Molecules

The reaction of the organometallic diarsene complex [Cp₂Mo₂(CO)₄(η²-As₂)] ( 1 ) with Ag[Al{OC(CF₃)₃}₄] (Ag[TEF]) yielded the Ag^I monomer [Ag(η²- 1 )₃][TEF] ( 2 ). This compound exhibits dynamic behavior in solution, which allows directed selective synthesis of unprecedented organometallic–organic hybrid assemblies upon its reaction with N-donor organic molecules by a stepwise pathway, which is supported by DFT calculations. Accordingly, the reaction of 2 with 2,2′-bipyrimidine ( L1 ) yielded the dicationic molecular compound [{(η²- 1 )₂Ag}₂(μ- L1 )][TEF]₂ ( 3 ) or the 1D polymer [{(η²- 1 )Ag}(μ- L1 )]_n[TEF]_n ( 4 ) depending on the ratio of the reactants. However, its reactions with the pyridine-based linkers 4,4′-bipyridine ( L2 ), 1,2-bis(4-pyridyl)ethylene ( L3 ) and 1,2-bis(4-pyridyl)ethyne ( L4 ) allowed the formation of the 2D polymers [{(η²- 1 )Ag}₂(μ- Lx )₃]_n[TEF]_2n [ Lx=L2 ( 5 ), L3 ( 6 ), L4 ( 7 ), respectively]. Additionally, this concept was extended to step-by-step one-pot reactions of 1 , [Ag(CH₃CN)₃][Al{OC(CF₃)₂(CCl₃)}₄] ([Ag(CH₃CN)₃][TEF^Cl]) and linkers L2 – L4 to produce the 2D polymers [{(η²- 1 )Ag}₂(μ, Lx )₃]_n[TEF^Cl]_2n [ Lx = L2 ( 8 ), L3 ( 9 ), L4 ( 10 ), respectively].     

A Global Review on Short Peptides: Frontiers and Perspectives

Peptides are fragments of proteins that carry out biological functions. They act as signaling entities via all domains of life and interfere with protein-protein interactions, which are indispensable in bio-processes. Short peptides include fundamental molecular information for a prelude to the symphony of life. They have aroused considerable interest due to their unique features and great promise in innovative bio-therapies. This work focusing on the current state-of-the-art short peptide-based therapeutical developments is the first global review written by researchers from all continents, as a celebration of 100 years of peptide therapeutics since the commencement of insulin therapy in the 1920s. Peptide “drugs” initially played only the role of hormone analogs to balance disorders. Nowadays, they achieve numerous biomedical tasks, can cross membranes, or reach intracellular targets. The role of peptides in bio-processes can hardly be mimicked by other chemical substances. The article is divided into independent sections, which are related to either the progress in short peptide-based theranostics or the problems posing challenge to bio-medicine. In particular, the SWOT analysis of short peptides, their relevance in therapies of diverse diseases, improvements in (bio)synthesis platforms, advanced nano-supramolecular technologies, aptamers, altered peptide ligands and in silico methodologies to overcome peptide limitations, modern smart bio-functional materials, vaccines, and drug/gene-targeted delivery systems are discussed.     

Role of Bacillus cereus in Improving the Growth and Phytoextractability of Brassica nigra (L.) K. Koch in Chromium Contaminated Soil

Plant growth-promoting rhizobacteria (PGPR) mediate heavy metal tolerance and improve phytoextraction potential in plants. The present research was conducted to find the potential of bacterial strains in improving the growth and phytoextraction abilities of Brassica nigra (L.) K. Koch. in chromium contaminated soil. In this study, a total of 15 bacterial strains were isolated from heavy metal polluted soil and were screened for their heavy metal tolerance and plant growth promotion potential. The most efficient strain was identified by 16S rRNA gene sequencing and was identified as Bacillus cereus. The isolate also showed the potential to solubilize phosphate and synthesize siderophore, phytohormones (indole acetic acid, cytokinin, and abscisic acid), and osmolyte (proline and sugar) in chromium (Cr⁺³) supplemented medium. The results of the present study showed that chromium stress has negative effects on seed germination and plant growth in B. nigra while inoculation of B. cereus improved plant growth and reduced chromium toxicity. The increase in seed germination percentage, shoot length, and root length was 28.07%, 35.86%, 19.11% while the fresh and dry biomass of the plant increased by 48.00% and 62.16%, respectively, as compared to the uninoculated/control plants. The photosynthetic pigments were also improved by bacterial inoculation as compared to untreated stress-exposed plants, i.e., increase in chlorophyll a, chlorophyll b, chlorophyll a + b, and carotenoid was d 25.94%, 10.65%, 20.35%, and 44.30%, respectively. Bacterial inoculation also resulted in osmotic adjustment (proline 8.76% and sugar 28.71%) and maintained the membrane stability (51.39%) which was also indicated by reduced malondialdehyde content (59.53% decrease). The antioxidant enzyme activities were also improved to 35.90% (superoxide dismutase), 59.61% (peroxide), and 33.33% (catalase) in inoculated stress-exposed plants as compared to the control plants. B. cereus inoculation also improved the uptake, bioaccumulation, and translocation of Cr in the plant. Data showed that B. cereus also increased Cr content in the root (2.71-fold) and shoot (4.01-fold), its bioaccumulation (2.71-fold in root and 4.03-fold in the shoot) and translocation (40%) was also high in B. nigra. The data revealed that B. cereus is a multifarious PGPR that efficiently tolerates heavy metal ions (Cr⁺³) and it can be used to enhance the growth and phytoextraction potential of B. nigra in heavy metal contaminated soil.