Reddish Powder Research Articles

New bioactive titanium(IV) derivatives with their DFT, molecular docking, DNA/BSA interaction, antioxidant and in-vitro investigations

A set of four new metallacyclic complexes titanium(IV) associated with Schiff bases (SBs) (1a- 1d) obtained by the specific reactions of β-diketones such as acetylacetone (acacH) and benzyl acetone (bzacH) and aminophenol derivatives while treating Ti(OPri)4 and these SBs individually in 1:2 stoichiometry under 8 h reflux condition in anhydrous benzene to afford as reddish powder (2a-2d). These products have been purified in repeated washings of dry n-hexane afterwards, subjected to characterization by suitable spectroscopic techniques (NMR, IR, UV–Vis and HRMS). These hexacoordinated complexes appeared as distorted octahedral geometry from computational data studies. The synthesized titanium(IV) complexes were screened for their antioxidant abilities where 2c and 2d exhibited remarkable activity as IC50 values. The DNA & BSA binding properties of the complexes (2a-2d) have also been investigated through electronic absorption and molecular docking analysis. The obtained results indicated clearly that the complexes got bound with DNA via groove binding mode according to the intrinsic binding constant values (Kb = 1.5 × 104 M−1 to 7.5 × 105 M−1). Derivative 2c was examined in-vitro on a panel of cancerous cell line − breast cancer and human colon cell lines MCF-7 to reflect IC50 results as 53.92 μg/mL and HT-29 33.43 μg/mL, respectively.

A micro-wear analysis of Natufian gazelle phalanx beads from el-Wad Terrace, Mount Carmel, Israel

The late Epipaleolithic Natufian Culture of the Levant (ca. 15,000–11,700 BP) is renowned for its rich bone industry. A specific type of bone bead, the gazelle phalanx bead, is abundant in several sites but nearly absent in others. In this study, phalanx bone beads from the current excavations at the Natufian site of el-Wad Terrace (Mount Carmel, Israel) were studied through use-wear analysis, integrated in an experimental program to reconstruct their production sequence, mode of suspension, and use. The experimental program included controlled experiments of abrasion, polishing, and drilling, replication experiments, and suspension experiments producing an extensive database of wear patterns. Based on the experimental program, the sequence of operations was inferred by detecting the intersection of the traces. A repetitive four-step procedure is reconstructed, including skinning the bone, scraping it and making a transversal cut with flint tools, then drilling the bone using the pump drill technique, followed by abrasion against limestone with water to create a smooth and polished bone surface. Reddish powder found on ten beads was chemically analyzed through SEM EDX indicating an additional step of coloring with ochre. Traces on the drilled holes indicate the use of organic fibers for suspension and a unique type of use-wear also showed the contact against leather material indicating that the Natufians utilized gazelle phalanx beads in their daily clothing. A well-established craft is therefore revealed, displaying the artistic capability to express the Natufian identity in a complex society where rules had to be portrayed to others so that organization and structure could maintain the (sedentary) community intact.

Synthesis route to δ-FeOOH nanodiscs

δ-FeOOH is a synthetic analogue of a relatively uncommon mineral feroxyhyte (δ′-FeOOH). The conventional syntheses of δ-FeOOH start from the Fe(II) salt and proceed by a rapid oxidation of iron(II) hydroxide with H2O2. The new synthesis route to δ-FeOOH nanodiscs reported in this work is based on the γ-irradiation of a deoxygenated iron(III) chloride alkaline aqueous colloidal solution in the presence of 2-propanol and diethylaminoethyl-dextran hydrochloride (DEAE-dextran). γ-irradiation of the colloidal solution enabled the strong reducing conditions thus favouring the reduction of Fe(III) to Fe(II). Under such strong reducing conditions the white suspension characteristic of Fe(OH)2 was formed. When the white suspension came into contact with oxygen from air it rapidly oxidized into stable green-gray suspension characteristic of Fe(II)-Fe(III) hydrochloride known as Green Rust I. In the conventional process of sample isolation the green-gray stable suspension transformed to δ-FeOOH reddish powder that consists of rather uniform regular nanodiscs. The synthesized δ-FeOOH nanodiscs are magnetic and contain a magnetically ordered component in the Mössbauer spectrum at room temperature. It is expected that the results of this work will have a strong impact on finding new synthetic routes to the δ-FeOOH.

Water-dispersible nanoparticles via interdigitation of sodium dodecylsulphate molecules in octadecylamine-capped gold nanoparticles at a liquid-liquid interface

This paper describes the formation of water-dispersible gold nano-particles capped with a bilayer of sodium dodecylsulphate (SDS) and octadecylamine (ODA) molecules. Vigorous shaking of abiphasic mixture consisting of ODA-capped gold nanoparticles in chloroform and SDS in water results in the rapid phase transfer of ODA-capped gold nanoparticles from the organic to the aqueous phase, the latter acquiring a pink, foam-like appearance in the process. Drying of the coloured aqueous phase results in the formation of a highly stable, reddish powder of gold nanoparticles that may be readily redispersed in water. The water-dispersible gold nanoparticles have been investigated by UV-Vis spectroscopy, differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and Fourier transform infrared spectroscopy (FTIR). These studies indicate the presence of interdigitated bilayers consisting of an ODA primary monolayer directly coordinated to the gold nanoparticle surface and a secondary monolayer of SDS, this secondary monolayer providing sufficient hydrophilicity to facilitate gold nanoparticle transfer into water and rendering them water-dispersible.

Formation of Water-Dispersible Gold Nanoparticles Using a Technique Based on Surface-Bound Interdigitated Bilayers

We demonstrate the phase transfer of dodecylamine (DDA)-capped colloidal gold particles dispersed in an organic solvent into water containing the cationic surfactant, cetyltrimethylammonium bromide (CTAB). Vigorous shaking of the biphasic mixture results in the rapid phase transfer of DDA-capped gold nanoparticles from the organic to aqueous phase, the aqueous phase acquiring a pink, foamlike appearance. Drying of the colored aqueous phase results in the formation of a highly stable reddish powder of gold nanoparticles that may be readily redispersed in water. The water-dispersible gold nanoparticles have been investigated by UV−vis spectroscopy, differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and Fourier transform infrared spectroscopy (FTIR). These studies indicate the presence of interdigitated bilayers consisting of a DDA primary monolayer directly coordinated to the gold particle surface and a secondary monolayer of CTAB, this secondary monolayer providing sufficient hydrophilicity to facilitate gold nanoparticle phase transfer and render them water-dispersible. The CTAB-DDA stabilized particles may be dispersed in water at very high nanoparticle concentrations with stability even in the presence of high amounts of electrolyte and over a wide range of solution pH.

Studies on galactose oxidase active site model complexes: effects of ring substituents on Cu(II)-phenoxyl radical formation

Copper(II) complexes of new N 3O- and N 2O 2-donor tripodal ligands bearing one or two o-substituted phenol moieties have been synthesized as models for the galactose oxidase active site. The complexes of 2-[ N-(1-methyl-2′-imidazolylmethyl)- N-(6″-methyl-2″-pyridylmethyl)-aminomethyl)]-4-methyl-6-methylthiophenol (MeSL), [Cu(MeSL)Cl], and N-(6-methyl-2-pyridylmethyl)- N, N-bis(2′-hydroxy-3′,5′-di- tert-butylbenzyl)amine (t-buL2mepy), [Cu(t-buL2mepy)(H 2O)], have been revealed by X-ray structural analysis to have a square-pyramidal structure with one and two phenolate oxygens in the basal plane, respectively. [Cu(MeSL)Cl] was converted into a Cu(II)- o-methylthiophenoxyl radical species by electrochemical or Ce(IV) oxidation. An o-methoxyphenoxyl radical in a similar complex was considerably more stable than the 2,4-di( tert-butyl)phenoxyl radical. While t-buL2mepy reacted with Cu(ClO 4) 2 to give [Cu(t-buL2mepy)(H 2O)] without disproportionation, an N2O2-donor ligand containing an o-methoxyphenol, a 2,4-di( tert-butyl)phenol, and an N-methylimidazole moiety gave a phenoxyl radical complex exhibiting the characteristic absorption peak at 478 nm as a reddish powder by the reaction with Cu(ClO 4) 2 as a result of spontaneous disproportionation. It exhibited a quasi-reversible redox wave at E 1/2=0.34 V (vs. Ag/AgCl) in CH 3CN, which is lower than the potentials of the copper complexes of various N 3O-donor ligands, and oxidized ethanol to acetaldehyde with a low turnover number.

The History of Plant Pathology in Australia

Plant pathology in Australia began in the last century as a result of sporadic rust epiphytotics blighted wheat crops and devastated part of the vital food supply of the pioneers. Soon after the first settlement was established in Australia in 1788, Governor Phillip devoted all his spare time to the question of providing food for the young colony (84). The first crop· of wheat was grown (46) in what is' now the Sydney Botanic Gardens (28) . Collins was the first to record disease in wheat in 1795 in a crop of bearded cape wheat which was not worth the labour of at Pe­ tersham Hill, now the site of Sydney University (111) . Early settlers refer­ red to disease of wheat crops as blights or accidents, and the disease could not be identified. Joseph Holt, a farmer, gave an accurate description of a rust-infected wheat crop at Dundas, New South Wales, in 1803. After a few days of foggy weather and within 3 weeks of harvest, wheat was reduced in value from £1400 to less than £20. It covers the whole wheat straw with reddish powder .... (84, 90). The early Governors frequently mentioned crop losses in their des­ P!ltches to the British Government. Governor King in his despatch of 1804 (46) reported: Our last year's crop was much injured by rusts and smuts. The early records of rust attacks in the Australian colonies have been re­ viewed by Waterhouse (111), who showed that rust epiphytotics occurred in 1799, 1803, 1805, 1829, 1832, 1860, 1863, 1864, 1867, andI889. Not long after the founding of Victoria in 1851, the Board of Agricul­ ture (forerunner of the Department of Agriculture) was established. Within 5 years three rust epiphytotics occurred, causing the Board to appoint a committee in 1864 to inquire into the causes and prevention of rust. F. Mueller (later Baron Sir Ferdinand von Mueller), Government Botanist and Director of the Melbourne Botanic Gardens, was chairman. The rust committee (72) determined the effect of agricultural practices on the inci­ dence of the disease and recommended early sowing and careful selection of wheat varieties as a means of control. In Australia this first official scientific inquiry into a major plant disease came at the time when plant pathology was established in Germany as a scientific discipline by de Bary. Following an outbreak of wheat rust in 1867 in South Australia the Gov­ ernment of that colony appointed a similar committee (88).