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The optimization of mining vehicle rear axle weld joints is a complex procedure. The designs for low-cycle fatigue with peak loads were analyzed using computational models and rig testing. On-road evaluation of high-cycle fatigue was performed with the entire vehicle. The iterative analysis is used in design optimization to minimize design cycle time. In sophisticated fatigue calculations with all affecting factors, FEM is utilized. In fatigue failures using road load data, the present deterministic method yields up to 80% correlations. Some critical failure spots were most likely missed owing to operational variations caused by the randomness and multiaxiality of load transfer in link mechanisms with non-linear elements. The fabricated rear axle housing joints are optimized by comparing damage state estimates using stochastic type and multiaxial equivalent loads obtained using Multibody Simulation. The damage state analysis as MBS input stimulus in FE weld models and bolted designs were compared. [ABSTRACT FROM AUTHOR]

Abstract: This report describes the preparation of antibacterially active emulsified polyacrylate nanoparticles in which a penicillin antibiotic is covalently conjugated onto the polymeric framework. These nanoparticles were prepared in water by emulsion polymerization of an acrylated penicillin analogue pre-dissolved in a 7:3 (w:w) mixture of butyl acrylate and styrene in the presence of sodium dodecyl sulfate (surfactant) and potassium persulfate (radical initiator). Dynamic light scattering analysis and atomic force microscopy images show that the emulsions contain nanoparticles of approximately 40nm in diameter. The nanoparticles have equipotent in vitro antibacterial properties against methicillin-susceptible and methicillin-resistant forms of Staphylococcus aureus and indefinite stability toward β-lactamase. [Copyright &y& Elsevier]

The solid-phase synthesis of DNA-interactive pyrrolo[2,1-c][1,4]benzodiazepine (PBD) imines and biologically important pyrrolo[2,1-c][1,4]benzodiazepine-5,11-diones on Wang resin using a reduction/cyclization procedure is reported. [Copyright &y& Elsevier]

Zinc oxide (ZnO) nanoparticles are emerged as a leading phtocatlyst for organic dye degradation owing to its non-toxicity, low cost and high photochemical reactivity. In the present work, ZnO nanoparticles with different particle size were prepared via hydrothermal assisted phytofabrication method using Aerva lanata and Aerva javanica flower extracts as the reducing agent. The synthesized ZnO nanoparticles were analyzed using different analytical techniques which evidently revealed that phase purity, structural properties, band gap and particle size of the ZnO nanoparticles were considerably influenced by the type of flower extract used as reducing agent under hydrothermal circumstance. The photocatalytic degradation of Rhodamine B was examined in the presence of prepared ZnO nanoparticles under visible light irradiation. Photocatlytic study clearly indicate that ZnO nanoparticles prepared using Aerva lanata flower extract exhibits superior photocatlytic degradation of Rhodamine B dye than ZnO prepared using Aerva javanica flower extract due to its inherent properties. Hence, the synthesized ZnO nanoparticles using hydrothermal assisted phytofabrication can be used as a potential photocatlyst for the removal of Rhodamine B dye from the textile waste water by photocatalytic degradation. [ABSTRACT FROM AUTHOR]

2-Azidopyrrolobenzodiazepines have been synthesized via cyclization of ω-azidocarbonyl compounds employing hexamethyldisilathiane by selectively reducing the aryl azido functionality. [Copyright &y& Elsevier]

The facile synthesis of C-8 linked pyrrolobenzodiazepine–naphthalimide hybrid analogues is described. The compounds are prepared with varying degrees of linker length in order to probe the structural requirements for optimal in vitro anti-tumour activity. Some of these new hybrid compounds showed higher cytotoxic activity than the existing natural and synthetic pyrrolo[2,1-c][1,4]benzodiazepines. [Copyright &y& Elsevier]

A versatile combinatorial approach was developed and utilized for the rapid synthesis of pyrrolo2,1-c1,4benzodiazepine-5,11-dione (PBD-5,11-dione) libraries 10, 15, and 19containing 210 compounds with varied substitutions in A, B, and C rings. The key aspect of the synthetic strategy includes Staudinger, intermolecular aza-Wittig reaction followed by imine reduction and base-mediated cyclative cleavage results in the formation of final resin-free compounds. This strategy provides a highly efficient and practical protocol for the parallel synthesis of PBD-5,11-diones on solid support. The modifications in the C-ring of the PBD scaffold produced three types of sublibraries. Reactions were monitored by FT-IR spectroscopy on the resin beads. Further, from a generated library of 210 compounds, 142 compounds have been selected and evaluated for in vitro activity against Mycobacterium tuberculosis, and some of these compounds have exhibited promising activity. [ABSTRACT FROM AUTHOR]

Abstract: This report describes the preparation of polyacrylate nanoparticles in which an N-thiolated β-lactam antibiotic is covalently conjugated onto the polymer framework. These nanoparticles are formed in water by emulsion polymerization of an acrylated antibiotic pre-dissolved in a liquid acrylate monomer (or mixture of co-monomers) in the presence of sodium dodecyl sulfate as a surfactant and potassium persulfate as a radical initiator. Dynamic light scattering analysis and electron microscopy images of these emulsions show that the nanoparticles are approximately 40nm in diameter. The emulsions have potent in vitro antibacterial properties against methicillin-resistant Staphylococcus aureus and have improved bioactivity relative to the non-polymerized form of the antibiotic. A unique feature of this methodology is the ability to incorporate water-insoluble drugs directly into the nanoparticle framework without the need for post-synthetic modification. Additionally, the antibiotic properties of the nanoparticles can be modulated by changing the length or location of the acrylate linker on the drug monomer. [Copyright &y& Elsevier]

Abstract: A study on the structure–activity profiles of N-thiolated β-lactams 1 is reported which demonstrates the importance of the N-organothio moiety on antibacterial activity. Our results indicate that elongation of the N-alkylthio residue beyond two carbons, or extensive branching within the organothio substituent, diminishes antibacterial effects. Of the derivatives we examined, the N-sec-butylthio β-lactam derivative 5g possesses the strongest growth inhibitory activity against methicillin-resistant Staphylococcus aureus strains. Sulfur oxidation state is important, as the N-sulfenyl and N-sulfinyl groups provide for the best antibacterial activity, while lactams bearing the N-sulfonyl or N-sulfonic acid functionalities have much weaker or no anti-MRSA properties. Stereochemistry within the organothio chain does not seem to be a significant factor, although for N-sec-butylthio β-lactams 15a–d, the 3R,4S-lactams 15c, d are more active than the 3S,4R-stereoisomers 15a, b in agar diffusion experiments. The N-methylthio lactams are the most sensitive to the presence of glutathione, followed by N-ethylthio and N-sec-butylthio lactams, which indicates that bioactivity and perhaps bacterial selectivity of the lactams may be related to the amount of organothiols in the bacterial cell. These results support the empirical model for the mechanism of action of the compounds in which the lactam transverses the bacterial membrane to deliver the organothio moiety to its cellular target. [Copyright &y& Elsevier]

Abstract: This report describes the evaluation of N-thiolated β-lactam antibiotics as potential anti-Bacillus agents. N-Thiolated β-lactams are a new family of antibacterials that previously have been found to selectively inhibit the growth of Staphylococcus bacteria over many other genera of microbes. From the data presented herein, these lactams similarly inhibit a variety of Bacillus species, including Bacillus anthracis. The preliminary structure–activity studies suggest that there is a need to balance the lipophilic character of the C3/C4 groups in order to obtain optimal anti-Bacillus activity. Elongation or extensive branching of the organothio substitutent diminishes antibacterial effects, with the sec-butylthio derivative providing the strongest activity. [Copyright &y& Elsevier]

An efficient and mild method for the reduction of aromatic nitro and azido groups on solid support using Al/NiCl2·6H2O and Al/NH4Cl is described. This solid phase reduction technique has been applied towards the synthesis of DNA binding pyrrolo[2,1-c][1,4]benzodiazepine antitumour antibiotics. [Copyright &y& Elsevier]