Soft mode analysis and ferroelectric transition in spherical nanoparticles

We address the dielectric behavior in a free standing spherical particle using the phenomenological Landau theory. Considering the equations of motion and small perturbation against uniform polarization, we obtain the size driven ferroelectricity. The size driven polarization is shown to diverge at a new correlation length which turns out to be the extrapolation length. Mode analysis in such systems is carried out and it is found that the size driven ferroelectricity is associated with a soft mode which takes a minimum value at the new transition temperature similar to that of the bulk system. We suggested that such a mode can be tested in Raman measurement.     

Facile and efficient preparation of hybrid phenylthiazolyl-1,3,5-triazines and their antidepressant-like effect in mice

High safety, robust efficacy, and rapid onset of action remain the key challenges for improving antidepressant drug discovery. We report a facile and efficient synthetic strategy to structurally encompass mono-, di-, or tri-substituted derivatives using cyanuric chloride and various substituted phenylthiazole-2-amines. The predicted physicochemical property precisely state their specificity as CNS acting agent and antidepressant-like effect of the most promising compound 10 after oral administration significantly reduced immobility in mice behavior models, especially TST from 63 s. In addition, good safety features of 10 highlight its ability to modulate hallmarks for antidepressant discovery. These insights are useful in generalization and systematization of CRF₁ antagonist design to develop future biological end points.     

Calix[4]arene based molecular probe for sensing copper ions

A novel calix[4]arene based molecular probe for metal ions has been designed, synthesized and evaluated. Studies on its binding with different metal ions reveal a noticeable naked eye color change, bathochromic shift in absorption spectrum and remarkable enhancement in fluorescence emission in the presence of Cu²⁺ only. The role of calix[4]arene scaffold for selective recognition of Cu²⁺ has been demonstrated by repeat evaluation and analysis of an appropriate reference molecule. A rational explanation for fluorescence enhancement in 3 on interaction with copper has been suggested.     

New lower rim looped calix[4]arene for ratiometric and chromogenic recognition of Cu2+

A new calix[4]arene derivative in its cone conformation and bearing Schiff base loop at the lower rim has been synthesized and evaluated as a specific molecular probe for copper ions. The new molecular receptor 4 shows a selective visible change in color from colorless to yellow only in the presence of Cu²⁺ ions which was confirmed by a significant bathochromic shift (?λ_max = 76 nm) in its absorption spectrum. The stoichiometry of the copper complex was calculated to be 1:1. These results may help to design more efficient chemical sensors for determining copper in biological systems.     

Ring Closure Reactions of Chalcones Using Microwave Technology

The synthesis of heterocyclic compounds containing pyrimidine, pyrazoline, isoxazoline and cyclohexenone ring from chalcone derivatives containing anisole and 3′4′-methylenedioxy phenyl ring under ‘dry conditions’ using microwaves and by conventional methods are described.     

H3Mo12O40P-Catalyzed One-Pot Synthesis of Amidoalkyl Naphthols

Solid H₃Mo₁₂O₄₀P is used for an efficient one-pot synthesis of amidoalkyl naphthols using aromatic aldehydes, β-naphthol, and urea or amides in carbon tetrachloride. The catalyst was efficiently recovered from the reaction mixture and reused with negligible loss of catalyst activity. Ambient conditions, simple workup, and good yield are some of the striking features of the present protocol.     

Benzimidazole-based chromogenic chemosensor for the recognition of oxalic acid via counter ion displacement assay in semi-aqueous medium

An azo dye-coupled benzimidazole-based receptor 1 was synthesized and investigated as a receptor for metal ions in semi-aqueous medium. The receptor recognizes Cu²⁺ with high selectivity over other metal ions. The resultant complex 1·Cu²⁺ was found to selectively bind oxalic acid via counter ion displacement.     

Thermal analysis of new dimethyl/dibutyl tin(IV) compounds with amino acids

Six diorganotin(IV) compounds with amino acids of general formula [(CH₃)₂SnAACl]₂ and [(CH₃CH₂CH₂CH₂)₂SnAACl]₂ (where AA = l-methioninate, l-cysteinate, and l-tryptophanate) were synthesized by reacting dimethyltin(IV) dichloride (M) and dibutyltin(IV) dichloride (B) with l-methionine (M₁) or l-cysteine (C) or l-tryptophan (T) using acetonitrile as solvent and designated as MM₁, MC, MT, BM₁, BC, and BT. The structural characterization of dimethyltin(IV) and dibutyltin(IV) compounds were done using elemental analysis, FT-IR, ¹H-NMR, ¹³C-NMR, and ¹¹⁹Sn-NMR spectroscopy. The thermal properties of the synthesized compounds were studied by thermogravimetric analysis and differential scanning calorimetry techniques in a dynamic atmosphere of nitrogen. The thermal decomposition mechanisms were similar for compounds MM₁, BM₁, MC, BC, and occurred in one step, while in compounds MT and BT it occurred in two consecutive steps. The TG curves of the MT and BT compounds suggest the loss of the ligand (AA) in the first step, with probable formation of a tin oxide R₂SnO intermediate. At the end of the second step free tin is obtained similar to the MM₁, BM₁, MC, BC in accordance with the stoichiometry of the related compounds.     

Inhibitors of tyrosine phosphatases and apoptosis reprogram lineage-marked differentiated muscle to myogenic progenitor cells

Muscle regeneration declines with aging and myopathies, and reprogramming of differentiated muscle cells to their progenitors can serve as a robust source of therapeutic cells. Here, we used the Cre-Lox method to specifically label postmitotic primary multinucleated myotubes and then utilized small molecule inhibitors of tyrosine phosphatases and apoptosis to dedifferentiate these myotubes into proliferating myogenic cells, without gene overexpression. The reprogrammed, fusion competent, muscle precursor cells contributed to muscle regeneration in?vitro and in?vivo and were unequivocally distinguished from reactivated reserve cells because of the lineage marking method. The small molecule inhibitors downregulated cell cycle inhibitors and chromatin remodeling factors known to promote and maintain the cell fate of myotubes, facilitating cell fate reversal. Our findings enhance understanding of cell-fate determination and create novel therapeutic approaches for improved muscle repair.