Thermophoresis and Brownian motion effects on boundary layer flow of nanofluid in presence of thermal stratification due to solar energy

The problem of laminar fluid flow,which results from the stretching of a vertical surface with variable stream conditions in a nanofluid due to solar energy,is investigated numerically.The model used for the nanofluid incorporates the effects of the Brownian motion and thermophoresis in the presence of thermal stratification.The symmetry groups admitted by the corresponding boundary value problem are obtained by using a special form of Lie group transformations,namely,the scaling group of transformations.An exact solution is obtained for the translation symmetrys,and the numerical solutions are obtained for the scaling symmetry.This solution depends on the Lewis number,the Brownian motion parameter,the thermal stratification parameter,and the thermophoretic parameter.The conclusion is drawn that the flow field,the temperature,and the nanoparticle volume fraction profiles are significantly influenced by these parameters.Nanofluids have been shown to increase the thermal conductivity and convective heat transfer performance of base liquids.Nanoparticles in the base fluids also offer the potential in improving the radiative properties of the liquids,leading to an increase in the efficiency of direct absorption solar collectors.     

One-pot synthesis of methyl piperazinyl–quinolinyl nicotinonitrile derivatives under microwave conditions and molecular docking studies with DNA

Derivatives of methyl piperazinyl–quinolinyl nicotinonitrile were synthesised by one-pot method under microwave conditions. This was achieved using the Knoevenagel condensation reaction. The novel derivatives described above were purified by column chromatography and characterised by FT-IR, ¹H, ¹³C, 2D-NMR and HRMS spectroscopic techniques. Furthermore, molecular docking was used to determine the binding sites of DNA with selected compounds. The synthetic method developed in this study showed several advantages including simplicity, high yield of products, coupled with safety and a short reaction time of 15 min.     

Bioinspired Water-soluble Polymers with Grafted Polyamine Chains: Synthesis and Complexation with Oligonucleotides

The siliceous frustules of diatom algae contain complex proteins known as silaffins, which consist of a peptide chain with grafted polyamine chains. These polyamines contain twenty or more nitrogen atoms with trimethylene groups between the nitrogens. We synthesized a set of polymers containing grafted long-chain polyamine fragments by using acryloyl chloride(ACh) polymers and activated acrylic acid copolymers as the starting materials. The new polymers contained 0.05 mol%-3.2 mol% of polyamine chains, which corresponded to 0.06-3.56 mmol·g~(-1) amine groups. The new amine-containing polymers formed complexes with short(19-21-mer)deoxyribonucleic acid(DNA) and ribonucleic acid(RNA) strands, and these complexes penetrated into model yeast cells and A549 lung cancer cell. This study demonstrates the potential of these species based on long-chain polyamines to serve as novel gene delivery systems.     

Structural features and N-H…O and O-H…O hydrogen-bonded supramolecular frameworks in 2-methylanilinium hydrogen DL-malate hydrate, 4-methoxyanilinium and 4-methylanilinium hydrogen DL-malate salts

In the crystal structure of 2-methylanilinium hydrogen DL-malate hydrate (I), an additional water molecule is present in asymmetric unit. In the crystal structures of 4-methoxyanilinium hydrogen DL-malate (II) and 4-methylanilinium hydrogen DL-malate (III), the hydrogen malate anions exhibit configurational disorder with major component occupy S-configuration and minor component occupy R-configuration provided both (II) and (III) are prepared from a racemic mixture of DL-malic acid. In crystal structures of compounds (I)–(III), the hydrogen malate anions and anilinium cations from O-H…O and N-H…O hydrogen bonds which exhibit interesting supramolecular frameworks. In compound (I), the N-H…O and O-H…O hydrogen-bonded anionic-cationic framework form two-dimensional hydrophilic and hydrophobic layers in which the lattice water molecules are embedded in hydrophilic layers. However, in crystal structures of (II) and (III), the hydrogen DL-malate anions form two-dimensional anionic substructure through O-H…O hydrogen bond, in which the anilinium cations are anchored through N-H…O hydrogen bonds.

     

Activation-controlled outer-sphere electron transfer reactions: reduction of heteropoly 11-tungstovanadophosphate and heteropoly 10-tungstodivanado phosphate by thiourea in aqueous acid medium

The kinetics of reduction of heteropoly 11-tungstovanadophosphate, [PV^VW₁₁O₄₀]⁴⁻, (HPA1) and heteropoly 10-tungstodivanadophosphate, [PV^VV^VW₁₀O₄₀]⁵⁻, (HPA2) by thiourea has been investigated in HClO₄/phthalate/acetate buffer solutions spectrophotometrically at 25 °C in aqueous medium. The stoichiometry of the reaction is 1:1 in both cases. The HPAs are converted into the corresponding one-electron reduced heteropoly blues, namely, [PV^IVW₁₁O₄₀]⁵⁻ and [PV^IVV^VW₁₀O₄₀]⁶⁻, and thiourea is oxidised to formamidine disulphide. The reaction shows first-order dependence in both [HPA] and [thiourea] at constant pH. The rate–pH profile shows the participation of both the neutral and deprotonated forms of thiourea in the reaction. The reaction proceeds through an outer sphere electron transfer mechanism in which activation-controlled electron transfer is the rate-determining step. Self-exchange rate constants for the couples [PV^VW₁₁O₄₀]⁴⁻/[PV^IVW₁₁O₄₀]⁵⁻, [PV^VV^VW₁₀O₄₀]⁵⁻/[PV^IVV^VW₁₀O₄₀]⁶⁻ and H₂NCSNH₂/H₂NCS^·+NH₂ have been evaluated by Marcus theory.     

Assessment of resolution parameters for CID-based shotgun proteomic experiments on the LTQ-Orbitrap mass spectrometer

Shotgun proteomics has been used extensively for characterization of a number of proteomes. High-resolution Fourier transform mass spectrometry (FTMS) has emerged as a powerful tool owing to its high mass accuracy and resolving power. One of its major limitations, however, is that the confidence level of peptide identification and sensitivity cannot be maximized simultaneously. Although it is generally assumed that higher resolution is better for peptide identifications, the precise effect of varying resolution as a parameter on peptide identification has not yet been systematically evaluated. We used the Escherichia coli proteome and a standard 48 protein mix to study the effect of different resolution parameters on peptide identifications in the setting of a shotgun proteomics experiment on an LTQ-Orbitrap mass spectrometer. We observed a higher number of peptide-spectrum matches (PSMs) whenever the MS scan was carried out by FT and the MS/MS in the ion-trap (IT) with the maximum PSMs obtained at an MS resolution of 30,000. In contrast, when samples were analyzed by FT for both MS and MS/MS, the number of PSMs was significantly lower (∼40% compared with FT-IT experiments) with the maximum PSMs obtained when both the MS and MS/MS resolution were set to 15,000. Thus, a 15K-15K resolution setting may provide the best compromise for studies where both speed and accuracy such as high-throughput post-translational analysis and de novo sequencing are important. We hope that our study will allow researchers to choose between different resolution parameters to achieve their desired results from proteomic analyses.     

Homotopy analysis method for thermophoretic particle deposition effect on magnetohydrodynamic mixed convective heat and mass transfer past a porous wedge in the presence of suction

Homotopy analysis method is used to analyze the effect of thermophoretic particle deposition on magnetohydrodynamic mixed convection flow with heat and mass transfer over a porous wedge. An explicit analytical solution is obtained which is valid throughout the solution domain and is consistent with numerical results.     

Synthesis and In Vivo antitumor and antiviral activities of 2′-deoxyribofuranosyl and arabinofuranosyl nucleosides of certain purine-6-sulfenamides,sulfinamides and sulfonamides

2′-Deoxyribofuranosyl and arabinofuranosyl nucleosides of certain purine-6-sulfenamides, sulfinamides and sulfonamides have been prepared by sequential amination and controlled oxidation of the corresponding 6-thiopurine nucleosides, and evaluated for antiviral and antitumor activities in mice. Amination of 2′-deoxy-6-thioinosine ( 4a ) and 9-β-D-arabinofuranosyl-6-thiopurine ( 4c ) with chloramine solution gave the corresponding 6-sulfenamides 5a and 5c , respectively, which on selective oxidation with 3-chloroperoxybenzoic acid (MCPBA) gave diastereomeric 9-(2-deoxy-β-D-erythro-pentofuranosyl)purine-6-sulfinamide ( 6a ) and 9-β-D-arabinofuranosylpurine-6-sulfinamide ( 6c ), respectively. However, oxidation of 5a and 5c with excess of MCPBA gave the corresponding 6-sulfonamide derivatives 7a and 7c , respectively. Similar amination of 2′-deoxy-6-thioguanosine ( 4b ), ara-6-thioguanine ( 4d ) and α-2′-deoxy-6-thioguanosine ( 8 ) gave the respective 6-sulfenamide derivatives 5b, 5d and 9 . Controlled oxidation of 5b, 5d and 9 gave (R,S)-2-amino-9-(2-deoxy-β-D-erythro-pentofuranosyl)purine-6-sulfinamide ( 6b ), (R,S)-2-amino-9-β-D-arabinofuranosylpurine-6-sulfinamide ( 6d ) and the α-anomer of ( 6b) (10 ), respectively. The diastereomeric mixture of (R,S )-10 was partially resolved and the structure of S -10 was assigned by single-crystal X-ray diffraction analysis. Oxidation of 5b, 5d and 9 with excess of MCPBA afforded the respective 6-sulfonamide derivatives 7b, 7d and 11 . Nucleosides 5c and 7c were significantly active against Friend leukemia virus in mice, whereas 6c was somewhat less active. Of the 20 nucleosides evaluated, 12 exhibited biologically significant anti-L1210 activity in mice. Nucleosides 6b and 7a at 173 mg/kg/day × 1 showed a T/C of 153, whereas 7d at 800 mg/kg/day × 1 showed a T/C of 153 against L1210 leukemia. The α-nucleoside 9 at 480 mg/kg/day × 1 gave a T/C of 172. A single treatment with 6b, 7a, 7d and 9 reduced the body burdens of viable L1210 cells by more than 99.2%. The antileukemic activity of these novel nucleosides tended to parallel solubility.