A novel amino acid functionalized ionic liquid promoted one-pot solvent-free synthesis of 3,4-dihydropyrimidin-2-(1H)-thiones

An environmentally benign, cheap and reusable L-amino acid functionalized ionic liquid [L-AAIL]/AlCl₃ was found to be an effective catalyst for the synthesis of 3,4-dihydropyrimidine-2-(1H)-thione derivatives in good to excellent yield under solvent-free condition. Compared with the classical Biginelli reactions, this method consistently enjoys the advantages of mild reaction conditions, easy work-up, and short reaction time. These one-pot three-component Biginelli products could be separated easily from the catalyst–water system, and the catalyst could be reused at least five times without noticeably reducing catalytic activity.     

The anomalous magnetisation of amorphous metglas 2826-A

Magnetisation measurements made on the amorphous ferromagnet Metglas 2826-A, (T_C = 254.5 K), in the temperature range 4.2 ≤ T ≤ 450 K indicate that it obeys the static scaling law hypothesis over an unusually wide temperature range. Analysis of the data give for the critical exponents δ = 5.07, β = 0.41, γ = 1.67. Moreover, above T_C a superparamagnetic model is discussed.     

Elevations of diffusion anisotropy are associated with hyper-acute stroke: a serial imaging study

Diffusion tensor imaging (DTI) studies of human ischemic stroke within 24 h of symptom onset have reported variable findings of changes in diffusion anisotropy. Serial DTI within 24 h may clarify these heterogeneous results. We characterized longitudinal changes of diffusion anisotropy by analyzing discrete ischemic white matter (WM) and gray matter (GM) regions during the hyperacute (2.5-7 h) and acute (21.5-29 h) scanning phases of ischemic stroke onset in 13 patients. Mean diffusivity (MD), fractional anisotropy (FA) and T2-weighted signal intensity were measured for deep and subcortical WM and deep and cortical GM areas in lesions outlined by a > or =30% decrease in MD. Average reductions of approximately 40% in relative (r) MD were observed in all four brain regions during both the hyperacute and acute phases post stroke. Overall, 9 of 13 patients within 7 h post symptom onset showed elevated FA in at least one of the four tissues, and within the same cohort, 11 of 13 patients showed reduced FA in at least one of the ischemic WM and GM regions at 21.5-29 h after stroke. The fractional anisotropy in the lesion relative to the contralateral side (rFA, mean+/-S.D.) was significantly elevated in some patients in the deep WM (1.10+/-0.11, n=4), subcortical WM (1.13+/-0.14, n=4), deep GM (1.07+/-0.06, n=1) and cortical GM (1.22+/-0.13, n=5) hyperacutely (< or =7 h); however, reductions of rFA at approximately 24 h post stroke were more consistent (rFA= 0.85+/-0.12).     

Chirally Twisted Ultrathin Polydopamine Nanoribbons: Synthesis and Spontaneous Assembly of Silver Nanoparticles on Them

Polydopamine (PDA) is a synthetic polymeric material with immense potential in biomedical and surface functionalization applications. Herein, we have screened self-assemblies formed by Phenylalanine-based amphiphiles (Phe-AMPs) as soft templates for preparing chiral PDA nanostructures. Our study revealed that the amphiphile 2 endowed with a primary amine residue afforded chirally-twisted ultrathin nanoribbons of PDA under optimized conditions. The chirality at the Phe residue of 2 modulated the twist-chirality of the PDA nanoribbons; the l -2 resulted in nanoribbons with right-handed twist, whereas the d -2 induced a left-handed twist to the ribbons. The racemic mixture of these two amphiphiles produced flat, achiral tapes. The PDA ribbon thickness was ≈5.86±0.40 nm, whereas its width and length were ≈133.5±3.2 nm and >5000 nm, respectively. Upon dialysis, hollow PDA nanotubes were obtained due to curling of the PDA nanoribbons. These PDA-nanoarchitectures were employed to spontaneously form and assemble Ag-nanoparticles along the edges of the PDA nanoribbons. In this work we are reporting chirality controlled synthesis of PDA nanostructures for the first time.     

Electrochemical deposition of cabbage-like lead microstructures on fluorine-doped tin oxide for oxygen sensor application

Journal of Solid State Electrochemistry - Metallic lead (Pb) has been electrodeposited on FTO substrate at room temperature from aqueous nitrate solution under constant applied potential in the...     

(Non-)expansivity in functional envelopes

We study expansivity in functional envelopes of dynamical systems. Our main result is that if the phase space of the original system contains an arc or if it contains a free infinite zero dimensional set, then the expansivity in the functional envelope with Hausdorff metric is impossible. This is in contrast with the fact that, when considering the uniform metric in functional envelopes, the expansivity of a system is equivalent with the expansivity of its functional envelope.     

Drug repurposing approach for the identification and designing of potential E6 inhibitors against cervical cancer: an in silico investigation

Structural Chemistry - Repurposing of ‘old’ drugs to treat both common and rare diseases has garnered huge attention of the researchers because of the high attrition rates and...     

Nanocomposite of bimetallic nanodendrite and reduced graphene oxide as a novel platform for molecular imprinting technology

In this present work, for the first time, we are reporting a green synthesis approach for the preparation of vinyl modified reduced graphene oxide-based magnetic and bimetallic (Fe/Ag) nanodendrite (RGO@BMNDs). Herein, the RGO@BMNDs acts as a platform for the synthesis of the pyrazinamide (PZA)-imprinted polymer matrix and used for designing of the electrochemical sensor. We have demonstrated how the change in morphology could affect the electrochemical and magnetic property of nanomaterials and for this the reduced graphene oxide-based bimetallic nanoparticle (Fe/Ag) was also prepared It was found that the combination of graphene and bimetallic nanodendrites shows improvement as well as enhancement in the electrocatalytic activity and adsorption capacity, in comparison to their respective nanoparticles. The application of imprinted-RGO@BMNDs sensor was explored for trace level detection of PZA (Limit of detection = 6.65 pg L⁻¹, S/N = 3), which is a drug used for the cure of Tuberculosis. This is lowest detection limit reported so far for the detection of PZA. The sensor is highly selective, cost-effective, simple and free from any interfering effect. The real time application of the sensor was explored by successful detection of PZA in pharmaceutical and human blood serum, plasma and urine samples.