Amberlyst-15 and Amberlite-200C: Efficient catalysts for aldol and cross-aldol condensation under ultrasound irradiation

This paper presents an improved synthesis of trans-chalcones and α,α′-bis(arylmethylidene) cycloalkanones under ultrasound irradiation in the presence of commercial acid-resins as catalysts in solvent free conditions. Several trans-chalcones and α,α′-bis(arylmethylidene) cycloalkanones were synthesized in good yields and excellent selectivity in a short reaction time.     

Differential Photoluminescent and Electrochemiluminescent Detection of Anions with a Modified Ruthenium(II)–Bipyridyl Complex

Different lights, different selectivies : Luminescence of a new guanidinium 3,3′‐functionalized bipyridyl–Ru^II complex has been studied for sensing of several anions. L ‐Glutamate and dihydrogenphosphate are both detected by photoluminescence and electrochemiluminescence. However, the complex displays differential selectivities for these anions depending on the sensing channels (see scheme).

     

Stochastic hard-sphere dynamics for hydrodynamics of nonideal fluids

A novel stochastic fluid model is proposed with a nonideal structure factor consistent with compressibility, and adjustable transport coefficients. This stochastic hard-sphere dynamics (SHSD) algorithm is a modification of the direct simulation Monte Carlo algorithm and has several computational advantages over event-driven hard-sphere molecular dynamics. Surprisingly, SHSD results in an equation of state and a pair correlation function identical to that of a deterministic Hamiltonian system of penetrable spheres interacting with linear core pair potentials. The fluctuating hydrodynamic behavior of the SHSD fluid is verified for the Brownian motion of a nanoparticle suspended in a compressible solvent.     

ACCR ring of the forms $$\mathcal {A}[X]$$ and $$\mathcal {A}[[X]]$$A[[X]]

Let \(\mathcal {A}=(A_n)_{n\in \mathbb {N}}\) be an ascending chain of commutative rings with identity and let \(\mathcal {A}[X]\) (respectively, \(\mathcal {A}[[X]]\)) be the ring of polynomials (respectively, power series) with coefficient of degree n in \(A_n\) for each \(n\in \mathbb {N}\) (Hamed and Hizem in Commun Algebra 43:3848–3856, 2015; Haouat in Thèse de doctorat. Faculté des Sciences de Tunis, 1988). An A-module M is said to satisfy ACCR if the ascending chain of residuals of the form \(N:B\subseteq N:B^2\subseteq N:B^3\subseteq \cdots \) terminates for every submodule N of M and for every finitely generated ideal B of A (Lu in Proc Am Math Soc 117:5–10, 1993). We give necessary and sufficient condition for the ring \(\mathcal {A}[X]\) (respectively, \(\mathcal {A}[[X]]\)) to satisfy ACCR.     

ApA Cleavage Promoted by Oxa-aza Macrocycles and Their Zn(II) Complexes. The Role of pH and Metal Coordination in the Hydrolytic Mechanism

Abstract

The thermodynamic parameters for protonation and Zn(II) complex formation with ligand 1,4,7,16,19,22-hexaza-10,13,25,28-tetraoxacyclotriacontane (L1) have been determined. L1 forms stable dizinc complexes from neutral to alkaline pH. The hydrolytic ability toward adenylyl(3′-5′)adenosine (ApA) of L1 and its dizinc(II) complexes have been analyzed by means of HPLC chromatography. Only partially protonated species of L promote ApA hydrolysis suggesting that the cleavage process is cooperatively promoted by a general base catalysis by neutral amine groups and a general acid catalysis by protonated ammonium functions. Concerning the Zn(II) complexes, the hydrolysis rates increase in the presence of the hydroxo complexes [Zn₂L1(OH)]³⁺ and [Zn₂L1(OH)²]²⁺. This indicates that Zn-OH functions play a crucial role in the hydrolytic process, assisting the deprotonation of the 2′-OH group of ApA, which may act as nucleophile in the cleavage process. Both binuclear L1 complexes are better catalysts than the mononuclear [ZnL₂(OH)]⁺ complex (L₂ = 1,4-Dioxa-7,10,13-triazacyclopentadecane), indicating a cooperative role of the two Zn(II) ions in ApA cleavage by [Zn₂L1(OH)]³⁺ and [Zn₂L1(OH)₂]²⁺, probably due to a bridging coordination of the phosphate moiety of ApA to the two metal centers.     

Interpenetrating single helical capsules

An aromatic oligoamide sequence designed to adopt a helically folded conformation surrounding a hollow space is shown to undergo hybridization into a double helical duplex in which the two strands fill each other's hollow.     

Micro‐Raman and IR study of the compressive behaviour of poly(paraphenylene benzobisoxazole) (PBO) fibres in a diamond‐anvil cell

The micro/nano structural evolution of PBO (poly(paraphenylenebenzobisoxazole), commercial name Zylon) fibres has been studied by Raman and IR spectroscopy in a diamond‐anvil cell, up to ∼15 GPa. Different modes were considered in the 900–1700 cm⁻¹ (Raman) and 800–3300 cm⁻¹ (IR) spectral range. The material behaviour appears more similar to that of a densely packed inorganic structure than to the behaviour previously observed for polyamide fibres, and is related to the compact arrangement of the rigid heterocyclic rings. Wavenumber shift starts with increase in pressure and a transition between the two regimes was revealed at ∼2–2.5 GPa, and it was assigned to the loss of order between neighbouring PBO chains. A good correlation is observed between the macroscopic mechanical properties and the nanomechanics at the chemical bond scale. Copyright © 2006 John Wiley & Sons, Ltd.     

The Lebanese Red Algae Jania rubens: Promising Biomolecules against Colon Cancer Cells

Colorectal cancer (CRC) is ranked the second most lethal type of tumor globally. Thus, developing novel anti-cancer therapeutics that are less aggressive and more potent is needed. Recently, natural bioactive molecules are gaining interest as complementary and supportive antineoplastic treatments due to their safety, effectiveness, and low cost. Jania rubens (J. rubens) is a red coral seaweed abundant in the Mediterranean and bears a significant pharmacological essence. Despite its therapeutic potential, the natural biomolecules extracted from this alga are poorly identified. In this study, the proximal analysis revealed high levels of total ash content (66%), 11.3% proteins, 14.5% carbohydrates, and only 4.5% lipids. The elemental identification showed magnesium and calcium were high among its macro minerals, (24 ± 0.5 mg/g) and (33 ± 0.5 mg/g), respectively. The Chlorophyll of J. rubens was dominated by other pigments with (0.82 ± 0.02 mg/g). A 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assay identified effective antioxidant activity in various J. rubens extracts. More importantly, a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) tetrazolium reduction and wound healing assays indicate that organic extracts from J. rubens significantly counteract the proliferation of colon cancer cell lines (HCT-116 and HT-29) and inhibit their migratory and metastatic properties in a dose and time-dependent manner. Overall, this study provides insight into the physicochemical properties of red seaweed, J. rubens, and identifies its significant antioxidant, cytotoxic, and anti-migratory potential on two colorectal cell lines, HCT-116 and HT-29.