Liquid-crystalline hybrid materials based on [60]fullerene and bent-core structures

What a core-ker! By the appropriate combination of promesogenic bent-core structures and the C(60) unit, lamellar polar liquid-crystal phases were induced. The supramolecular organization of the functional fullerene-based assemblies, the temperature range of the soft phase, the stabilization of the mesophase-like order at room temperature, and the molecular switching under an electric field can be tuned, depending on the molecular structure.     

Ion trap mass spectrometry on a comet nucleus: the Ptolemy instrument and the Rosetta space mission

In May 2014, the Rosetta spacecraft is scheduled to rendezvous with the comet Churyumov-Gerasimenko ('67P'). One of the instruments on board the 'Lander' which will descend on to the surface of the comet is a miniaturised GC/MS system that incorporates an ion trap mass spectrometer, specially developed for isotope ratio analysis. This article describes the development and optimisation of the ion trap for this unique application, and presents a summary of the range of pre-programmed experiments that will contribute to the characterisation of the solid and volatile cometary materials.     

New heteroleptic palladium(II) dithiocarbamates: synthesis,characterization, packing and anticancer activity against five different cancer cell lines

Two new heteroleptic palladium(II) complexes have been synthesized by reacting equimolar quantities of palladium(II) chloride, sodium 4‐(2‐methoxyphenyl)piperazine‐1‐carbodithioate and diphenyl‐p‐tolylphosphine ( 1 ) or tri‐p‐tolylphosphine ( 2 ). Complexes 1 and 2 have been characterized using elemental analysis, Fourier transform infrared spectroscopy, multinuclear NMR (¹H, ¹³C and ³¹P) spectroscopy and single‐crystal X‐ray analysis. The latter technique confirms a pseudo square‐planar geometry in which two adjacent positions are occupied by bidentate dithiocarbamate while chloro and substituted triphenylphosphine are present at the remaining two positions. The anticancer activity of both complexes against five different cancer cell lines (LU – human lung carcinoma, established at UIC, Department of Surgical Oncology; MCF7 – human breast adenocarcinoma, ATCC number HTB‐22?; MDA‐MB‐231 – human breast adenocarcinoma, ATCC number HTB‐26?; Hepa‐1c1c7 – mouse liver hepatoma, ATCC number CRL‐2026?; PC‐3 – human prostate adenocarcinoma, ATCC number CRL‐1435?) was determined by MTT assay, revealing 2 has higher activity than 1 . A drug–calf thymus DNA binding study with UV–visible spectroscopy reveals a higher DNA binding affinity of 2 (3.511 × 10⁴ M^?1) than 1 (4.213 × 10³ M^?1). Density functional theory studies confirm the relatively more stable nature of 2 than 1 . Copyright © 2016 John Wiley & Sons, Ltd.     

New 3D and 2D supramolecular heteroleptic palladium(II) dithiocarbamates as potent anticancer agents

Three new heteroleptic palladium(II) dithiocarbamates with better in vitro anticancer activity than cisplatin were synthesized and characterized by different analytical techniques, elemental analysis, FTIR, NMR, and single crystal X-ray diffraction analysis. The Pd center is chelated by dithiocarbamate ligand {4-benzylpiperazine-1-carbodithioate (1) and (3) or (4-(2-methoxyphenyl)piperazine-1-carbodithioate (2)}, triorganophosphine {tris-(4-flourophenyl)-phosphine (1) and (2) or tris-(4-chlorophenyl)phosphine (3)}, and a chloro-group, resulting in a square planar geometry. The packing diagram reveals a 3D network (1 and 2) and a 2D network (3) composed of various 1D chains in which the molecules are linked via hydrogen bonds (1–3) and halide?π (1, 3) interactions. The anticancer activities of complexes against HeLa cell line varies in the sequence 2 (23.438 μM) > 1 (38.293 μM) > 3 (47.554 μM) > cisplatin (78.075 μM). The cytotoxicity of these complexes is due to their strong induction of oxidative stress and DNA-damage ability leading to apoptosis.     

Highly fluorescent crystalline and liquid crystalline columnar phases of pyrene-based structures

A concept for highly ordered solid-state structures with bright fluorescence is proposed: liquid crystals based on tetraethynylpyrene chromophores, where the rigid core is functionalized with flexible, promesogenic alkoxy chains. The synthesis of this novel material is presented. The thermotropic properties are studied by means of differential scanning calorimetry (DSC), cross-polarized optical microscopy (POM), and X-ray diffraction. The mesogen possesses an enantiotropic Col(h) phase over a large temperature range before clearing. The material is highly fluorescent in solution and, most remarkably, in the condensed state, with a broad, strongly red shifted emission. Fluorescence quantum yields (Phi(F)) have been determined to be 70% in dichloromethane solution and 62% in the solid state. Concentration- and temperature-dependent absorption and emission studies as well as quantum-chemical calculations on isolated molecules and dimers are used to clarify the type of intermolecular interactions present as well as their influence on the fluorescence quantum yield and spectral properties of the material. The high luminescence efficiency in the solid state is ascribed to rotated chromophores, leading to an optically allowed lowest optical transition.     

Determination of the stereochemistry of anhydroerythromycin A, the principal degradation product of the antibiotic erythromycin A

Anhydroerythromycin A arises from the acid-catalysed degradation of erythromycin A both in vitro and in vivo. It has negligible antibacterial activity, but inhibits drug oxidation in the liver, and is responsible for unwanted drug-drug interactions. Its structure has 18 chiral centres common with erythromycin A, but C-9 (the spiro carbon) is also chiral in anhydroerythromycin and its stereochemistry has not previously been reported; both 9R- and 9S-anhydroerythromycin A are plausible structures. An understanding of the chirality at C-9 was expected to throw light on the mechanism of acid-catalysed degradation of erythromycin A, a subject that has been debated in the literature over several decades.We now report a determination of the three-dimensional structure of anhydroerythromycin A, including the stereochemistry at C-9, by NMR and molecular modelling. In parallel, the relative stereochemistry of anhydroerythromycin A 2'-acetate was determined by X-ray crystallography. Both compounds were shown to have 9R stereochemistry, and anhydroerythromycin A exhibited considerable conformational flexibility in solution.     

Resilient and agile engineering solutions to address societal challenges such as coronavirus pandemic

The world is witnessing tumultuous times as major economic powers including the US, UK, Russia, India, and most of Europe continue to be in a state of lockdown. The worst-hit sectors due to this lockdown are sales, production (manufacturing), transport (aerospace and automotive) and tourism. Lockdowns became necessary as a preventive measure to avoid the spread of the contagious and infectious “Coronavirus Disease 2019” (COVID-19). This newly identified disease is caused by a new strain of the virus being referred to as Severe Acute Respiratory Syndrome CoronaVirus 2 (SARS CoV-2; formerly called 2019-nCoV). We review the current medical and manufacturing response to COVID-19, including advances in instrumentation, sensing, use of lasers, fumigation chambers and development of novel tools such as lab-on-the-chip using combinatorial additive and subtractive manufacturing techniques and use of molecular modelling and molecular docking in drug and vaccine discovery. We also offer perspectives on future considerations on climate change, outsourced versus indigenous manufacturing, automation, and antimicrobial resistance. Overall, this paper attempts to identify key areas where manufacturing can be employed to address societal challenges such as COVID-19.     

The Navruz experiment: Cooperative monitoring for radionuclides and metals in Central Asia transboundary rivers

Summary This paper presents the results of radioecological investigation of Central Asian rivers.<Emphasis Type=Bold><Emphasis Type=Italic> </Emphasis></Emphasis>This work was done as part of the Navruz Project, a cooperative, transboundary river monitoring project involving rivers and institutions in Kazakhstan, Kyrgyzstan, Tajikistan, and Uzbekistan, and facilitated by Sandia National Laboratories in the United States. The study of waterborne radionuclides and metals concentrations in Central Asia is of particular interest because of the history of nuclear materials mining, fabrication, transport, and storage there, when it was part of the Soviet Union. This development left a legacy of radionuclides and metals contamination in some Central Asian regions, which poses a clear health hazard to populations who rely heavily upon surface water for agricultural irrigation and direct domestic consumption.