A new modified Laplace decomposition method for higher order boundary value problems

In this article, we suggest modified Laplace decomposition method for analytical solution of eighth-order boundary value problems (BVPs). The numerical application indicates the effectiveness and stability of the proposed algorithm. The efficiency of proposed method is examined with the help of linear and nonlinear problems.     

Monomeric bis(2,4‐pentane­dionato)­cobalt(II)

The title compound, [Co(C₅H₇O₂)₂], contains isolated mol­ecules. The Co atom is located on a centre of symmetry with the bidentate ligands adopting a square‐planar geometry about the Co atom.     

Recent advances in sodium alginate-based membranes for dehydration of aqueous ethanol through pervaporation

Sodium alginate (SA) is a progressive material for membrane fabrication. The technological development of SA-based membranes has made a significant contribution to the separation techniques, especially in aqueous organic solutions. The outstanding performance of SA is attributed to its outstanding structural flexibility and hydrophilicity. In view of structural characteristics, SA membranes have immense utilization in the pervaporation separation of organics. Among various organics, dehydration of aqueous ethanol is employed as a standard to check the success of pervaporation (PV) membrane. Because ethanol and water have comparable molecular sizes, thus difficult to extract water from aqueous ethanol mixtures than it is for other organics. A literature survey shows that wide-ranging data are available on the PV performance of SA and its modified membranes. In this context, the present review addresses the recent advances made in SA membranes for enhanced ethanol dehydration performance during the last decade. Available data since 2010 has been compiled for grafted, crosslinked, blend, mixed matrix, and composite hybrid sodium alginate membranes in terms of separation factor, permeation flux, and pervaporation separation index PSI. The data are assessed with reference to the effect of feed composition, membrane selectivity, flux, and swelling behavior.     

Thermally stable epoxy polymers from new tetraglycidyl amine-based resin

Journal of Thermal Analysis and Calorimetry - A tetraglycidyl amines-based epoxy resin, namely 4-(2-(4-(bis(oxiran-2-ylmethyl)amino)phenoxy)ethoxy)-N,N-bis(oxiran-2-ylmethyl)benzenamine (TGAE), was...     

NH4Cl/Zn powder: An efficient,chemoselective reducing catalyst for the microwave-assisted synthesis of 2,3-disubstituted quinolines via tandem Knoevenagel condensation

An efficient, a hitherto unreported, sustainable, and environmentally friendly microwave-assisted synthesis of 2,3-disubstituted quinolines by reductive cyclization of 2-nitrobenzaldehydes and various active methylene compounds via tandem Knoevenagel condensation promoted by an efficient eco-friendly, chemoselective reducing catalyst ammonium chloride (NH₄Cl) and zinc powder was developed. This present methodology is a mild, green, efficient, and environmentally benign process as it eliminates the harsh reaction conditions, non-volatile solvents, relatively expensive reagents, high catalyst loading, and also provides a number of other benefits like fast synthesis, simple reaction set-up, and good to the excellent yield of the products.     

Effect of potassium permanganate on morphological,structural and electro-optical properties of graphene oxide thin films

This work investigated the effect of Potassium Permanganate (KMnO₄) on graphene oxide (GO) properties, especially on electrical properties. The GO thin films were deposited on a glass substrate using drop casting technique and were analysed by using various type of spectroscopy (e.g. Scanning Electron Microscopy (SEM), Ultra- Violet Visible (UV–VIS), Fourier Transform Infrared (FTIR), X-Ray Diffraction (XRD), optical band gap, Raman Spectroscopy). Furthermore, the electrical experiments were carried out by using current–voltage (I-V) characteristic. The GO thin film with 4.5 g of KMnO₄ resulted in higher conductivity which is 3.11 × 10^?4 S/cm while GO with 2.5 g and 3.5 g of KMnO₄ achieve 2.47 × 10^?9 S/cm and 1.07 × 10^?7 S/cm, respectively. This further affects the morphological (SEM), optical (band gap, UV–Vis, FTIR, and Raman), and crystalline structural (XRD) properties of the GO thin films. The morphological, elemental, optical, and structural data confirmed that the properties of GO is affected by different amount of KMnO₄ oxidizing agent, which revealed that GO can potentially be implemented for electrical and electronic devices.     

9-Acylation of 1-acyldipyrromethanes containing a dialkylboron mask for the alpha-acylpyrrole motif

1,9-Diacyldipyrromethanes are important precursors to porphyrins, yet synthetic access remains limited owing to (1) poor conversion in the 9-acylation of 1-acyldipyrromethanes and (2) handling difficulties because acyldipyrromethanes typically streak upon chromatography and give amorphous powders upon attempted crystallization. A reliable means for converting a dipyrromethane to a 1-acyldipyrromethane-dialkylboron complex was recently developed, where the dialkylboron (BR(2)) unit renders the complex hydrophobic and thereby facilitates isolation. Herein a refined preparation of 1,9-diacyldipyrromethanes is presented that employs the 1-acyldipyrromethane-BR(2) complex as a substrate for 9-acylation. The dialkylboron unit provides protection for the alpha-acylpyrrole unit. 9-Acylation requires formation of the pyrrolyl-MgBr reagent and the presence of 1 equiv of a nonnucleophilic base to quench the proton liberated upon alpha-acylation. Reaction of the 1-acyldipyrromethane-BR(2) complex (1 equiv) with mesitylmagnesium bromide (2 equiv) followed by the addition of an acylating agent (S-2-pyridyl thioate or acid chloride, 1.1 equiv) gives the corresponding 1,9-diacyldipyrromethane-BR(2) complex. The acylation method afforded 1,9-diacyldipyrromethane-BR(2) complexes with limited or no chromatography in yields of 64-92%. The 1,9-diacyldipyrromethane-BR(2) complexes are stable to routine handling, are readily soluble in common organic solvents, crystallize readily, and can now be prepared in multigram quantities through use of stoichiometric quantities of reagents.     

Coarsening of nanodomains by reorganization of polysiloxane segments at high temperature in polyurethane/α,ω-aminopropyl polydimethylsiloxane blends

The reaction in bulk at high temperature of α,ω-aminopropyl oligodimethylsiloxane and thermoplastic polyurethane (TPU) allowed observing interesting behavior. Mixing at 200 °C first involved dissociation of urethanes and splitting of polyurethane chains followed by reaction of the released isocyanates with amino end-groups of the oligosiloxane. At this stage, a copolymer was formed which morphology consisted of a very fine dispersion of the polysiloxane domains at the nanoscale (20 nm) with a narrow size dispersity. The polymer blend was perfectly transparent. Increasing the reaction time resulted in a significant coarsening of the morphology and a consequent loss of transparency. The reason for such a morphology evolution has been elucidated. The progressive formation of alkyl–alkyl urea linkages at the expense of aryl–alkyl bonds obtained earlier in the process caused an increase in the average number of successive polydimethylsiloxane (PDMS) blocks that organized in larger domains. The average number of consecutive polysiloxane segments was found to evolve from ～1.5 in the first 10–15 min to a value of 3–5 at the end of the reactive process.     

A UPLC-DAD-Based Bio-Screening Assay for the Evaluation of the Angiotensin Converting Enzyme Inhibitory Potential of Plant Extracts and Compounds: Pyrroquinazoline Alkaloids from Adhatoda vasica as a Case Study

Angiotensin converting enzyme (ACE) plays a crucial role in regulating blood pressure in the human body. Identification of potential ACE inhibitors from medicinal plants supported the idea of repurposing these medicinal plants against hypertension. A method based on ultra-performance liquid chromatography (UPLC) coupled with a diode array detector (DAD) was used for the rapid screening of plant extracts and purified compounds to determine their ACE inhibitory activity. Hippuryl-histidiyl-leucine (HHL) was used as a substrate, which is converted into hippuric acid (HA) by the action of ACE. A calibration curve of the substrate HHL was developed with the linear regression 0.999. The limits of detection and quantification of this method were found to be 0.134 and 0.4061 mM, respectively. Different parameters of ACE inhibitory assay were optimized, including concentration, incubation time and temperature. The ACE inhibition potential of Adhatoda vasica (methanolic-aqueous extract) and its isolated pyrroquinazoline alkaloids, vasicinol (1), vasicine (2) and vasicinone (3) was evaluated. Compounds 1–3 were characterized by various spectroscopic techniques. The IC₅₀ values of vasicinol (1), vasicine (2) and vasicinone (3) were found to be 6.45, 2.60 and 13.49 mM, respectively. Molecular docking studies of compounds 1–3 were also performed. Among these compounds, vasicinol (1) binds as effectively as captopril, a standard drug of ACE inhibition.     

Natural Small Molecules in Breast Cancer Treatment: Understandings from a Therapeutic Viewpoint

Breast cancer (BrCa) is the most common malignancy in women and the second most significant cause of death from cancer. BrCa is one of the most challenging malignancies to treat, and it accounts for a large percentage of cancer-related deaths. The number of cases requiring more effective BrCa therapy has increased dramatically. Scientists are looking for more productive agents, such as organic combinations, for BrCa prevention and treatment because most chemotherapeutic agents are linked to cancer metastasis, the resistance of the drugs, and side effects. Natural compounds produced by living organisms promote apoptosis and inhibit metastasis, slowing the spread of cancer. As a result, these compounds may delay the spread of BrCa, enhancing survival rates and reducing the number of deaths caused by BrCa. Several natural compounds inhibit BrCa production while lowering cancer cell proliferation and triggering cell death. Natural compounds, in addition to therapeutic approaches, are efficient and potential agents for treating BrCa. This review highlights the natural compounds demonstrated in various studies to have anticancer properties in BrCa cells. Future research into biological anti-BrCa agents may pave the way for a new era in BrCa treatment, with natural anti-BrCa drugs playing a key role in improving BrCa patient survival rates.