Lubricant degradation and related wear of a steel pin in lubricated sliding against a steel disc

In lubricated sliding contacts, components wear out and the lubricating oil ages with time. The present work explores the interactive influence between lubricant aging and component wear. The flat face of a steel pin is slid against a rotating steel disk under near isothermal conditions while the contact is immersed in a reservoir of lubricant (hexadecane). The chemical changes in the oil with time are measured by vibrational spectroscopy and gas chromatography. The corresponding chemistry of the pin surface is recorded using X-ray photoelectron spectroscopy while the morphology of the worn pins; surface and subsurface, are observed using a combination of focused ion beam milling and scanning electron microscopy. When compared to thermal auto-oxidation of the lubricant alone, steel on steel friction and wear are found to accentuate the decomposition of oil and to reduce the beneficial impact of antioxidants. The catalytic action of nascent iron, an outcome of pin wear and disk wear, is shown to contribute to this detrimental effect. Over long periods of sliding, the decomposition products of lubricant aging on their own, as well as in conjunction with their products of reaction with iron, generate a thick tribofilm that is highly protective in terms of friction and wear.     

In vitro protein and starch digestibility of pearl millet (Pennisetum gluacum L.) as affected by processing techniques

The effect of malting and blanching on the in vitro protein and starch digestibility of pearl millet (Pennisetum gluacum L.) were investigated. Pearl millet seeds were subjected to malting [steeping (16 h), germination (48 and 72 h) and kilning (24 h at 50 degrees C)] and blanching (30 s at 98 degrees C) treatments, before grinding to flour. The results indicated that both the treatments improved the in vitro digestibility significantly. Malting appreciably improved the in vitro protein (14-26%) and starch (86-112%) digestibility and improvement by malting was significantly higher than blanching. The effect of malting with 72 h of germination was most remarkable in improving the in vitro protein and starch digestibility.     

Automatic test-generation for predicates [software testing]

The authors propose a new technique for the automatic generation of test cases for predicates. Earlier, they proposed an efficient effective test generation strategy for Boolean expressions. They now extend this strategy to predicates. Their new strategy addresses several issues, including: analysis of dependencies between relational expressions in a predicate 𝒫; generation of test constraints for 𝒫 based on the detection of Boolean and relational operator faults in 𝒫; and generation of actual tests according to the generated test constraints for 𝒫. They propose: the use of constraint logic programming (CLP) to automate test-data generation for a predicate; and an incremental approach to apply CLP techniques to solve a constraint system. Since their technique is specification-based, it can facilitate generation of anticipated outputs for actual tests     

L-menthol-based initiators for atom transfer radical polymerization of styrene

Two new atom transfer radical polymerization (ATRP) initiators, 2-isopropyl-5-methylcyclohexyl 2-bromopropanoate ( 1 ) and 2-Isopropyl-5-methylcyclohexyl 2-bromo-2-methylpropanoate ( 2 ), have been synthesized by the reaction of 2-bromopropanoyl bromide and 2-bromo-2-methylpropanoyl bromide, respectively, with L-menthol and characterized by ¹H and ¹³C NMR and FTIR spectroscopic studies. ATRP of styrene has successfully been carried out in a control manner using these initiators along with catalyst/ligand system consisting of Cu(I)Br/N,N,N ^/,N ^/,N ^//-pentamethyldiethylenetriamine. Polymerizations have yielded polystyrenes (PSts) of controlled molecular weight with low polydispersity index having a menthyl end group, as confirmed by ¹H NMR and gel permeation chromatography [GPC]. The controlled nature of the polymerization has also been confirmed by kinetic study of the polymerization process monitored via ¹H NMR and GPC. Initiator 2 has evolved as most efficient among the two. The obtained end-functional PSt has also been used as a macroinitiator for homochain extension with styrene and heterochain extension with methyl methacrylate to produce PSt-b-PMMA, showing the living nature of the polymerization process. In comparison with the PSt sample prepared using widely used initiator ethyl-2-bromo-isobutyrate with almost the same molecular weight and polydispersity, initiator 2 -made L-menthyl-capped PSt has shown higher light transmission properties of its dichloromethane solution at ~259 nm, higher thermal stability, lower glass transition temperature, a broad melting temperature, and higher surface roughness over its film. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47964.     

Biodegradable polymer blends: miscibility,physicochemical properties and biological response of scaffolds

This review provides an overview of synthetic biodegradable polymer blends prepared for tissue engineering applications and aims at establishing structure‐physicochemical‐biological properties relationships. The characteristics of blends consisting of semi‐crystalline/semi‐crystalline and semi‐crystalline/amorphous polymers are presented. Their biological properties such as degradability and biocompatibility and their biological performance as scaffolds in relation to cell adhesion, proliferation, infiltration, morphology and type are discussed. From available data, it can be deduced that miscibility influences physicochemical properties of the corresponding biodegradable polymeric blend scaffold, which in turn impacts on biological response. Immiscibility in polymer blends generally translates into good cell adhesion and proliferation. However, better cellular infiltration has been noted in compatible blends compared to immiscible blends. Factors such as crystallinity versus amorphous character, chirality, surface properties, degradation rate/products, mechanical properties and scaffold fabrication techniques are shown to have a major bearing on cell growth. © 2015 Society of Chemical Industry     

Expression of carotenoid biosynthetic pathway genes and changes in carotenoids during ripening in tomato (Lycopersicon esculentum)

To study the expression pattern of carotenoid biosynthetic pathway genes, changes in their expression at different stages of maturity in tomato fruit (cv. Arka Ahuti) were investigated. The genes regulating carotenoid production were quantified by a dot blot method using a DIG (dioxigenin) labelling and detection kit. The results revealed that there was an increase in the levels of upstream genes of the carotenoid biosynthetic pathway such as 1-deoxy-d-xylulose-5-phosphate reductoisomerase (DXR), 4-hydroxy-3-methyl-but-2-enyl diphosphate reductase (Lyt B), phytoene synthase (PSY), phytoene desaturase (PDS) and ζ-carotene desaturase (ZDS) by 2-4 fold at the breaker stage as compared to leaf. The lycopene and β-carotene content was analyzed by HPLC at different stages of maturity. The lycopene (15.33 ± 0.24 mg per 100 g) and β-carotene (10.37 ± 0.46 mg per 100 g) content were found to be highest at 5 days post-breaker and 10 days post-breaker stage, respectively. The lycopene accumulation pattern also coincided with the color values at different stages of maturity. These studies may provide insight into devising gene-based strategies for enhancing carotenoid accumulation in tomato fruits.     

Bioprocess for Hyperactive Thermotolerant Aspergillus fumigatus Phytase and its Application in Dephytinization of Wheat Flour

Catalysis Letters - In the present study, statistically optimized production of thermotolerant Aspergillus fumigatus phytase was carried out in batch fermentation (1-L). An enhancement in phytase...     

Ultra-Structural Imaging Provides 3D Organization of 46 Chromosomes of a Human Lymphocyte Prophase Nucleus

Three dimensional (3D) ultra-structural imaging is an important tool for unraveling the organizational structure of individual chromosomes at various stages of the cell cycle. Performing hitherto uninvestigated ultra-structural analysis of the human genome at prophase, we used serial block-face scanning electron microscopy (SBFSEM) to understand chromosomal architectural organization within 3D nuclear space. Acquired images allowed us to segment, reconstruct, and extract quantitative 3D structural information about the prophase nucleus and the preserved, intact individual chromosomes within it. Our data demonstrate that each chromosome can be identified with its homolog and classified into respective cytogenetic groups. Thereby, we present the first 3D karyotype built from the compact axial structure seen on the core of all prophase chromosomes. The chromosomes display parallel-aligned sister chromatids with familiar chromosome morphologies with no crossovers. Furthermore, the spatial positions of all 46 chromosomes revealed a pattern showing a gene density-based correlation and a neighborhood map of individual chromosomes based on their relative spatial positioning. A comprehensive picture of 3D chromosomal organization at the nanometer level in a single human lymphocyte cell is presented.