Quantitative analysis of multi-element oxide thin films by angle-resolved XPS: Application to ultra-thin oxide films on MgAl substrates

An original procedure has been developed for the quantitative analysis and microstructural interpretation of angle-resolved X-ray photoelectron spectra (AR-XPS) of very thin (<6 nm), multi-element oxide films as grown on metallic binary alloy substrates by, e.g., thermal or plasma oxidation. To this end, first an approach has been given to retrieve the different metallic, oxidic and oxygen primary zero-loss (PZL) intensities from the measured AR-XPS spectra of the bare and oxidized alloy. The principal equations for the determination of the oxide-film thickness, composition and constitution from the resolved PZL intensities have been presented. On this basis, various corresponding calculation routes have been distinguished. The procedure has been applied to the case of very thin (<6 nm), mixed (Mg, Al)-oxide films on bare Mg-based MgAl substrates as grown by dry, thermal oxidation at room temperature. The results obtained on the thickness, composition, defect structure and constitution of the oxide-film have been discussed as function of the bulk Al alloying content and the applied partial pressure of oxygen.     

Microporous Hypercross-linked Conjugated Quinonoid Chromophores of Anthracene: Novel Polymers for CO2 Adsorption

Microporous hypercross-linked conjugated quinonoid chromophores represent a novel class of amorphous polymers, synthesized by the reaction of anthracene with dimethoxy methane in the presence of FeCl3 catalyst. Their N2 adsorption isotherms confirm their microporous nature. Diffuse reflectance UV-Visible(DRS UV-Vis) spectroscopy confirms their matrix built with the conjugated quinonoids by their broad light absorption characteristics extending from 1000 nm to 200 nm with the absorbance maximum close to 400 nm. The catalyst cross-linked anthracene with ―CH2― bridges and subsequently dehydrogenating them to form quinonoids. Their Fourier transform infrared(FTIR) spectra showed their characteristic quinonoid vibrations between 1600 and 1700 cm-1. The synthesis of polymers was carried out at 30, 40, 50, 60, 70 and 80 ℃, but the quinonoid content of the polymer obtained at 80 ℃ was higher than that of the others. Their scanning electron microscopy(SEM) images showed microspheres of 1 to 5 μm size built with tiny particles. Their surfaces were not smooth. The polymer synthesized at 80 ℃ showed 5.1 wt% CO2 sorption at 25 ℃ and 0.1 MPa, but when it was recross-linked, the CO2 sorption increased to 8 wt%. Hence, hypercross-linked conjugated quinonoid chromophores of anthracene are good for sorption of CO2.     

Molecular Understanding of Collagen Stabilization: Interaction of Valeraldehyde with Collagen

The present study explains the molecular level interaction of valeraldehyde with collagen. Valeraldehyde is a monoaldehyde, which involves crosslinking with protein through covalent linkages. The role of valeraldehyde as a crosslinking agent for collagen stabilization was studied. Molecular modeling approaches was used to understand the interaction of collagen like peptide with valeraldehyde, which mimic the aldehyde tanning processes involved in protein stabilization. Crosslinking efficiency of valeraldehyde was found to increase with an increase in concentration due to the higher availability of aldehydic groups involved in crosslinking with collagen. Valeraldehyde interacted collagen membrane showed an increase in thermal stability by 25°C at pH 8. In the presence of valeraldehyde, collagen fibrils nucleation center was shifted from a lower to a higher range. Shift in the nucleation center was observed in the reduction of gelling time. Water accessibility in valeraldehyde interacted collagen membrane was reduced due to a higher crosslinking rate in the collagen. Modified collagen membrane by valeraldehyde at incubation of about 96 h showed higher resistance to collagenolytic activity of 81%. The amino groups reacting appear to be involved in crosslinking with valeraldehyde. Several interaction sites were identified and the docking energy obtained was ?5.539 kcal/mol. The participation of the aldehyde group with amino groups in collagen was observed, which plays a dominant role in the stabilization of peptide by valeraldehyde. It was found that complexes exhibit covalent bonding, hydrogen bonding and electrostatic interaction in the process of stabilization.     

PROMETHEE based sustainable concept selection

Manufacturing organisations started recognising the importance of sustainability concepts: This is due to increasing government regulations and the consciousness of the sustainable products among the customers. In general, the sustainability concepts are classified into economic, environment and social perspectives. The classification of sustainable concept concerning to manufacturing firms can be material oriented, product design oriented and manufacturing process oriented. Sustainable concept selection is a vital problem for the contemporary manufacturing organisations. The selection process includes multiple criteria, therefore a Multi-Criteria Decision Making (MCDM) method namely, PROMETHEE (Preference Ranking Organisational Method for Enrichment Evaluation) is used in the study to select the best sustainable concept considering the criteria from social, economical and natural perspectives. The study revealed that the change of material as the best orientation and it implies that the material should be done at the first stage to achieve sustainability in the case organisation.     

A New Abietane Diterpenoid from Plectranthus bishopianus Benth.

Chemical examination of the MeOH extract of Plectranthus bishopianus Benth ., a rare and endangered plant, resulted in isolation of a new abietane diterpene, 6β‐hydroxy‐7α‐methoxyroyleanone ( 1 ), along with two more diterpenoids, 6,7‐dehydroroyleanone, and 6β,7α‐dihydroxyroyleanone, a triterpene oleanolic acid, and two sterols, β‐sistosterol and stigmasterol. The structures of the isolated compounds were elucidated on the basis of spectroscopic data and also by comparison with authentic samples.     

Application of fuzzy compromise solution method for fit concept selection

The modern manufacturing environment is highly turbulent so as to satisfy the dynamic needs of customers’. To enable the achievement of competitiveness in this complex business environment, newer manufacturing strategies have been introduced for enabling waste elimination and enhancing flexibility and responsiveness of systems. Fit manufacturing is a competitive manufacturing paradigm which includes lean and agile systems coupled with sustainable benefits. This article presents a study in which the concept selection in fit environment was formulated as Multi Criteria Decision Making (MCDM) problem and solved using fuzzy based compromise solution method, Vlsekriterijumska Optimizacija I Kompromisno Resenje (VIKOR). The selected concept design of automotive component was subjected to implementation in the case organisation.     

Abnormalities of cell packing density and dendritic complexity in the MeCP2 A140V mouse model of Rett syndrome/X-linked mental retardation

Background  

Rett syndrome (RTT), a common cause of mental retardation in girls, is associated with mutations in the MECP2 gene. Most human cases of MECP2 mutation in girls result in classical or variant forms of RTT. When these same mutations occur in males, they often present as severe neonatal encephalopathy. However, some MECP2 mutations can also lead to diseases characterized as mental retardation syndromes, particularly in boys. One of these mutations, A140V, is a common, recurring missense mutation accounting for about 0.6% of all MeCP2 mutations and ranking 21^st by frequency. It has been described in familial X-linked mental retardation (XLMR), PPM- X syndrome (Parkinsonism, Pyramidal signs, Macroorchidism, X-linked mental retardation) and in other neuropsychiatric syndromes. Interestingly, this mutation has been reported to preserve the methyl-CpG binding function of the MeCP2 protein while compromising its ability to bind to the mental retardation associated protein ATRX.     

Cognitive dysfunction in NF1 knock-out mice may result from altered vesicular trafficking of APP/DRD3 complex

Background  

It has been estimated that more than 50% of patients with Neurofibromatosis type 1 (NF1) have neurobehavioral impairments which include attention deficit/hyperactivity disorder, visual/spatial learning disabilities, and a myriad of other cognitive developmental problems. The biological mechanisms by which NF1 gene mutations lead to such cognitive deficits are not well understood, although excessive Ras signaling and increased GABA mediated inhibition have been implicated. It is proposed that the cognitive deficits in NF1 are the result of dysfunctional cellular trafficking and localization of molecules downstream of the primary gene defect.     

Solvent free oxidation of ethylbenzene over Ce-BTC MOF

A cerium based metal–organic framework (MOF) Ce-BTC (BTC = 1,3,5-benzenetricarboxylic acid) was synthesized using a solvothermal route and was characterized via powder XRD, BET, SEM, TGA, DRS-UV–vis, FT-IR, and ESR analyses. Oxidative catalytic performance of the synthesized catalyst was evaluated using ethylbenzene oxidation under optimum conditions. The results obtained suggest that the catalyst was efficient in the oxidation of EB with 84.99% conversion and 95.63% selectivity.     

Nearly monodisperse silica microparticles form in silicone (pre)elastomer mixtures

The formation of silica from a tetraalkoxysilane in a sol-gel process usually requires a highly polar, typically aqueous, medium that aids in the hydrolysis of the silane and leads to electrostatic stabilization of the growing silica particles. Formation of such silica particles in a hydrophobic medium is much more challenging. We report the formation of silica microspheres within silicone oils (hydroxy-terminated poly(dimethylsiloxane), HO-PDMS) during elastomer cure using atmospheric humidity in a one-pot and one-step synthesis. Using tetraethyl orthosilicate (TEOS) as both cross-linker and silica precursor, and aminopropyl-terminated dimethylsiloxane oligomer (AT-PDMS) as a catalytic surfactant, silica particles of low polydispersity formed near or at the air interface of the elastomer: the presence of a hydrophilic polymer, poly(ethylene glycol) (PEG), had an indirect effect on the particle formation, as it assisted with water transmission into the system, which resulted in particle formation over a wider range of parameters and facilitated silicone elastomer cure further away from the air interface. Depending on the relative humidity during cure, the sizes of particles presenting at the air interface varied from ~6-7 μm under ambient conditions (20-30%RH) to ~7-9 μm at high relative humidity (90% RH). The origin of the controlled particle synthesis is ascribed to the relative solubility of the catalyst and the efficiency of water permeation through the silicone matrix. AT-PDMS preferentially migrates to the air interface, as shown by ninhydrin staining, where it both catalyzes alkoxysilane hydrolysis and condensation, and stabilizes the growing silica particles prior to aggregation. Since reactions in the presence of this catalyst are slow, TEOS can migrate from within the pre-elastomer body to the interface faster than water can penetrate the silicone, such that the main locus of hydrolysis/condensation leading both to silica formation and elastomer cross-linking is at the air interface.