Introduction of Ag/CuO/MCM‐48 as an efficient catalyst for the one‐pot synthesis of novel pyran‐pyrrole hybrids

Bimetallic silver and copper incorporated mesoporous MCM‐48 (Ag/CuO/MCM‐48) was synthesized by simple wet‐impregnation method. The knowledge about its structural properties was gathered by means of Fourier transform‐infrared, energy‐dispersive X‐ray, X‐ray diffraction, field emission‐scanning electron microscopy, transmission electron microscopy and Brunauer–Emmett–Teller analyses. The catalytic activity of Ag/CuO/MCM‐48 was examined in the one‐pot three‐component reaction of 3‐(1‐methyl‐1H‐pyrrol‐2‐yl)‐3‐oxopropanenitrile, malononitrile and various aromatic aldehydes leading to novel pyran‐pyrrole hybrid derivatives in reduced reaction times (5–10 min) and excellent yields (88–97%). Application of Ag/CuO/MCM‐48 as a potent heterogeneous catalyst with good reusability up to five times, use of ethanol as an eco‐compatible medium and chromatography‐free work‐up are some crucial green aspects of this procedure.     

Toward design and fabrication of wind-driven vehicles: Procedure to optimize the threshold of driving forces

Wind energy has been continuously considered as a green, available, and economical alternative source of energy. For centuries, the transformed wind energy to drag-force has been used for transportation in watercrafts. With improvement of aerodynamics, the airfoil was invented to create and use a higher magnitude aerodynamic force, lift-force, in order to elevate airplanes. Later, the lift-force was horizontally applied as the thrust force in land/water wind-crafts. Whereas in airplanes horizontal airfoils (wing) create a vertical lift-force, installed vertical airfoils (wing-sail) produce a horizontal lift-force in wind-crafts. Therefore, this force can be used as thrust (driving) force in lift-based ice, water, and land vehicles. If the prevailing wind is constantly available, the vehicle speed can even exceed the wind velocity. Due to the complex kinematics of such vehicles, however, it should be noted that there would be always an optimum for the thrust force in order to control and navigate the vehicle to the destination point, and to avoid the severe undesired side-forces. This optimum is calculated in wind-craft trajectory software (WTS) which requires many inputs, including variable and constant parameters. Variable parameters consist of wind direction and magnitude in addition to vehicle’s position, velocities, and accelerations. On the other hand, design characteristics of the wind-driven vehicle are known as constant parameters. The land-yacht body’s drag is an unknown constant parameter which alters according to the relative wind. This implies that several wind tunnel experiment in different wind directions and speeds are required in order to obtain the drag coefficients.Therefore in order to bypass the wind tunnel measurements, this study aims to propose a fast and economical procedure to find the aforementioned drag coefficient by integration of a measurement and by a simulation approach. The obtained data can be later used in the optimization and control module of the WTS. The performance of this procedure has been investigated using a case study. For this purpose, a 1:4 prototype three-wheel land-yacht is first designed and fabricated. The land-yacht comprises of three major parts; horizontal airfoil (axle), vertical airfoil, and body. The dimensions of these elements are obtained after development of a code based on kinematics of the land-yacht. The axle is designed to increase the stability of the land-yacht, whereas the shape of the body is intended to produce a low drag coefficient in various directions. Furthermore, a set of experiments has been conducted to measure the body drag of the land-yacht in a direction parallel to the relative wind. This experiment is later used to develop and validate a computational fluid dynamics (CFD) model in order to estimate the drag of the land-yacht body in its various directions against the relative wind. The results show the adequate efficacy of this procedure to provide the required data for the optimization and control module of the WTS.     

Design and synthesis of novel polyglycerol hybrid nanomaterials for potential applications in drug delivery systems

The synthesis of a new drug delivery system based on hybrid nanomaterials containing a β-CD core and hyperbranched PG is described. Conjugating PG branches onto β-CD not only increases its water solubility but also affects its host/guest properties deeply. It can form molecular inclusion complexes with small hydrophobic guest molecules such as ferrocene or FITC with reasonable release. In addition, the achievable payloads are significantly higher as for carriers such as hyperbranched PGs. Short-term in vitro cytotoxicity and hemocompatibility tests on L929 cell lines show that the hybrid nanomaterial is highly biocompatible. Due to their outstanding properties, β-CD-g-PG hybrid nanomaterials are introduced as promising materials for nanomedicine, e.g., for drug delivery issues.     

HAp‐encapsulated γ‐Fe2O3‐supported dual acidic heterogeneous catalyst for highly efficient one‐pot synthesis of benzoxanthenones and 3‐pyranylindoles

A novel method is reported for the synthesis of benzoxanthenone and 3‐pyranylindole derivatives via one‐pot three‐component reactions using a newly synthesized HAp‐encapsulated γ‐Fe₂O₃‐supported dual acidic heterogeneous catalyst, as a reusable and highly efficient nanocatalyst. In this protocol the use of the nanocatalyst provided a green, useful and rapid method to generate products in short reaction times (4–20 min) and in excellent yields (87–96%). The paramagnetic nature of the catalyst provided a simple, trouble‐free and facile approach for the separation of the catalyst by applying an external magnet, and it could be used in eight cycles without significant loss in catalytic efficiency.     

Evaluating the Synthesis of Bis‐pyrazolines

The bis‐cyclization of chalcone with thiosemicarbazide under basic condition led to the formation of new compounds, thiocarbamoyl bis‐pyrazoline derivatives. Bis‐chalcones were prepared by a Claisen–Schmidt condensation between 1 mol bis‐aldehyde and 2 mol acetophenone derivatives in the presence of sodium hydroxide as a catalyst. The structures of all compounds were elucidated by IR, ¹H NMR, and ¹³C NMR spectral data and by elemental analyses.     

Convenient Ultrasound-Promoted Regioselective Synthesis of Fused 6-Amino-3-methyl-4-aryl-1H-pyrazolo[3,4-b]pyridine-5-carbonitrile

A multicomponent, catalyst-free reaction for the synthesis of fused 6-amino-3-methyl-4-aryl-1H-pyrazolo [3,4-b] pyridine-5-carbonitrile from 3-amino-5-methylpyrazole, malononitrile, and substituted aldehydes under ultrasound irradiation in short reaction times (8–10 min) with good yields (85–98%) is reported.

Bilipschitz homogeneous Jordan curves

We characterize bilipschitz homogeneous Jordan curves by utilizing quasihomogeneous parameterizations. We verify that rectifiable bilipschitz homogeneous Jordan curves satisfy a chordarc condition. We exhibit numerous examples including a bilipschitz homogeneous quasicircle which has lower Hausdorff density zero. We examine homeomorphisms between Jordan curves.

     

Generation of a Novel High-Affinity Monoclonal Antibody with Conformational Recognition Epitope on Human IgM

As IgM is the first isotype of antibody which appears in blood after initial exposure to a foreign antigen in the pattern of primary response, detection, and quantification of this molecule in blood seems invaluable. To approach these goals, generation, and characterization of a highly specific mAb (monoclonal antibody) against human IgM were investigated. Human IgM immunoglobulins were used to immunize Balb/c mice. Spleen cells taken from the immunized animals were fused with SP2/O myeloma cells using PEG (polyethylene glycol, MW 1450) as fusogen. The hybridomas were cultured in HAT containing medium and supernatants from the growing hybrids were screened by enzyme-linked immunosorbent assay (ELISA) using plates coated with pure human IgM and the positive wells were then cloned at limiting dilutions. The best clone designated as MAN-1, was injected intraperitoneally to some Pristane-injected mice. Anti-IgM mAb was purified from the animals’ ascitic fluid by protein-G sepharose followed by DEAE-cellulose ion exchange chromatography. MAN-1 interacted with human IgM with a very high specificity and affinity. The purity of the sample was tested by SDS-PAGE and the affinity constant was measured ( K_\texta = \text3.\text5 ×\text10^\text9\textM^{\text - 1} ) \left( {{K_{\text{a}}} = {\text{3}}.{\text{5}} \times {\text{1}}{0^{\text{9}}}{{\text{M}}^{{\text{ - 1}}}}} \right) . Immunoblotting and competitive ELISA were done and the results showed that the harvested antibody recognizes a conformational epitope on the μ chain of human IgM and there was no cross-reactivity with other subclasses of immunoglobulins. Furthermore, isotyping test was done and the results showed the subclass of the obtained mAb which was IgG₁κ.     

Results on the Grundy chromatic number of graphs

Given a graph G, by a Grundy k-coloring of G we mean any proper k-vertex coloring of G such that for each two colors i and j, i<j, every vertex of G colored by j has a neighbor with color i. The maximum k for which there exists a Grundy k-coloring is denoted by Γ(G) and called Grundy (chromatic) number of G. We first discuss the fixed-parameter complexity of determining Γ(G)?k, for any fixed integer k and show that it is a polynomial time problem. But in general, Grundy number is an NP-complete problem. We show that it is NP-complete even for the complement of bipartite graphs and describe the Grundy number of these graphs in terms of the minimum edge dominating number of their complements. Next we obtain some additive Nordhaus-Gaddum-type inequalities concerning Γ(G) and Γ(G^c), for a few family of graphs. We introduce well-colored graphs, which are graphs G for which applying every greedy coloring results in a coloring of G with χ(G) colors. Equivalently G is well colored if Γ(G)=χ(G). We prove that the recognition problem of well-colored graphs is a coNP-complete problem.