A Classical Cosmological Model for Triviality

The aim of this paper is to study the triviality of λ ϕ⁴ theory in a classical gravitational model. Starting from a conformal invariant scalar tensor theory with a self-interaction term λ ϕ⁴, we investigate the effect of a conformal symmetry breaking emerging from the gravitational coupling of the large-scale distribution of matter in the universe. Taking in this cosmological symmetry breaking phase the infinite limit of the maximal length (the size of the universe) and the zero limit of the minimal length (the Planck length) implies triviality, i.e. a vanishing coupling constant λ. It suggests that the activity of the self-interaction term λ ϕ⁴ in the cosmological context implies that the universe is finite and a minimal fundamental length exists.     

Crystal structures and in vitro anticancer studies on new unsymmetrical copper(II) Schiff base complexes derived from meso-1,2-diphenyl-1,2-ethylenediamine: a comparison with related symmetrical ones

Two new unsymmetrical copper(II) Schiff base complexes, [CuLⁿ(py)]ClO₄ (n = 1, 2) in which Lⁿ represents a tridentate N₂O type Schiff base ligand, were synthesized. Lⁿs were derived from monocondensation of meso-1,2-diphenyl-1,2-ethylenediamine with salicylaldehyde or 3-methoxysalicylaldehyde. The reaction between [CuLⁿ(py)]ClO₄ and other salicylaldehyde derivatives resulted in new N₂O₂ unsymmetrical tetradentate Cu^II complexes, CuL^3–6. Crystal structures of [CuL¹(py)]ClO₄, CuL⁴, and CuL⁵ were obtained. These new complexes as well as a series of related symmetrical ones (i.e. CuL^7–12) were tested for their in vitro anticancer activity against human liver cancer cell line (Hep-G2) by MTT and apoptosis assay. All of the complexes showed considerable cytotoxic activity against tumor cell lines (IC₅₀ = 5.13–16.24 μg mL^?1). The symmetrical CuL⁷ was the most potent anticancer derivative (IC₅₀ = 5.13 μg mL^?1) compared to the control drug 5-FU (IC₅₀ = 5.4 μg mL^-1, p < 0.05). Flow cytometry experiments showed that the copper derivatives especially [CuL²(py)]ClO₄ and CuL⁷ induced more apoptosis on Hep-G2 tumor cell lines compared to 5-FU.     

Quantum computation of the properties of helium using two-body and three-body intermolecular potentials: a molecular dynamics study

We have performed the molecular dynamics simulation to obtain energy, pressure, and self-diffusion coefficient of helium at different temperatures and densities using Lennard–Jones (LJ), Hartree–Fock dispersion-Individual damping (HFD-ID) potential, and the HFD-like potential which has been obtained with an inversion of viscosity data at zero pressure supplemented by quantum corrections following the Feynman–Hibbs approach. The contribution of three-body interactions using an accurate simple relationship reported by Wang and Sadus between two-body and three-body interactions has been also involved for non-effective potentials (HFD-ID and HFD-like) in simulation. Our results show a good agreement with corresponding experimental data. A comparison of our simulated results with other molecular simulations using different potentials is also included.     

Efficient synthesis of mono- and disubstituted 2,3-dihydroquinazolin-4(1H)-ones using KAl(SO4)2·12H2O as a reusable catalyst in water and ethanol

KAl(SO₄)₂·12H₂O was found to catalyze efficiently a one-pot three-component cyclocondensation of isatoic anhydride and primary amines or ammonia sources such as (NH₄)₂CO₃, NH₄OAc and NH₄Cl with aromatic aldehydes under mild conditions to afford the corresponding mono- and disubstituted 2,3-dihydroquinazolin-4(1H)-ones in good yields.     

A Proline-Based Aminophosphinic Acid Ligand and It’s Vanadyl Complex: Synthesis,Characterization and In Vitro Inhibitory Effects on α-Amylase And α-Glucosidase

Abstract

A proline-based aminophosphinic acid ligand and it's vanadium complex have been synthesized and characterized by spectroscopic techniques. The inhibitory activity on pancreatic α-amylase and Baker's yeast α-glucosidase has been examined in vitro. The novel complex showed more inhibitory potency against pancreatic α-amylase and Baker's yeast α-glucosidase compared to acarbose as an antidiabetic drug.

Supplemental materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements to view the free supplemental file.     

Design and fabrication of poly (glycerol sebacate)‐based fibers for neural tissue engineering: Synthesis,electrospinning, and characterization

Poly (glycerol sebacate) (PGS) is a thermoset biodegradable elastomer considered as a promising candidate material for nerve applications. However, PGS synthesis is very time and energy consuming. In this study, the PGS pre‐polymer (pPGS) was synthesized using three synthesis times of 3, 5, and 7 hours at 170°C. Fourier transform infrared (FTIR), nuclear magnetic resonance spectroscopy, X‐ray diffraction analysis, and differential scanning calorimetry thermogram were utilized to study the pPGS behavior. Poly (vinyl alcohol) was used as a carrier to fabricate aligned poly (vinyl alcohol)‐poly (glycerol sebacate) (PVA‐PGS) fibers with various ratios (60:40, 50:50, and 40:60) using electrospinning and crosslinked through the thermal crosslinking method. Morphology of the fibers was studied before and after crosslinking using scanning electron microscopy (SEM). FTIR, mechanical properties in the dry and wet state, water contact angle, in vitro degradation, and water uptake behavior of crosslinked scaffolds were also investigated. 3‐(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyltetrazolium bromide (MTT) assay, SEM analysis, and 4′, 6‐diamidino‐2‐phenylindole (DAPI) staining were utilized to determine the biocompatibility of scaffolds. The results show the synthesized pPGS in 3 hours at 170°C is the optimized sample in the terms of chemical reaction. All scaffolds have bead‐free and a uniform fiber diameter. The Young's modulus of crosslinked PVA‐PGS (50:50 and 40:60) fibers is shown to be in the expected range for nerve applications. The cell culture studies reveal PVA‐PGS (50:50 and 40:60) fibers could lead to better cell adhesion and proliferation. The results suggest that PVA‐PGS (50:50 and 40:60) is a suitable and promising biodegradable material in the fabrication of scaffolds for nerve regeneration.     

Experimental investigation of the adhesion force of single and double-layer coatings on MEMS surfaces

Adhesion force is one of the most important factors in microelectromechanical systems (MEMS), especially for microassembly. It depends on operating conditions and is affected by the contact area. In this study, the adhesion force between MEMS materials and AFM tips was analysed using AFM's point-mode spectroscopy. The aim was to study the effectiveness of various coatings in MEMS adhesion surfaces. For this purpose, five silicon surfaces were used, four of which were coated, and one was noncoated. Two of them were deposited by single-layer coating (Au and Ag). The other two were deposited by double-layer coating (TiO₂/Au, TiO₂/Ag) on a Si (1 0 0) substrate. The depositing was accomplished by the thermal evaporation method. Composite materials and analysis were reviewed by observing the SEM image. The experimental results showed that the method of deposition helped to decrease the adhesion force between the probe tip and the surface of the specimens, and double-layer coating had stronger effect on decreasing the adhesion force than the single-layer coating.     

Novel flower-like Sn–Cu and cactus-like Sn–Ag nanocatalysts for photo catalytically removal of toxic pollutant

In this study, dendrite-like Sn nanocomposites were achieved by engineering the synthesis parameters. The dendritic Sn nanostructures show higher photocatalytic activity compared to nanoplate Sn and hierarchical Sn nanostructures. Flower-like Sn–Cu and cactus-like Sn–Ag nanostructures were prepared to improve the photocatalytic activity of Sn nanostructures. Adding Cu and Ag improved the photocatalytic activity of Sn by 24% and 46%, respectively. The photodegradation results revealed that the cactus-like Sn–Ag has a high degradation rate (5.3 × 10⁻⁴ mmol L⁻¹ min⁻¹) compared to the Sn nanostructures (2.9 × 10⁻⁴ mmol L⁻¹ min⁻¹). This work provides new insight into the design of highly efficient photocatalysts by engineering the morphology.