The role of particle size of particulate nano-zinc oxide wood preservatives on termite mortality and leach resistance

Historically most residential wood preservatives were aqueous soluble metal formulations, but recently metals ground to submicron size and dispersed in water to give particulate formulations have gained importance. In this study, the specific role nano-zinc oxide (ZnO) particle size and leach resistance plays in termite mortality resulting from exposure to particulate ZnO-treated wood was investigated. Southern yellow pine (SYP) sapwood impregnated with three concentrations of two particle sizes (30 and 70 nm) of ZnO were compared to wood treated with soluble zinc sulphate (ZnSO₄) preservative for leach resistance and termite resistance. Less than four percent leached from the particulate nano-ZnO-treated specimens, while 13 to 25% of the zinc sulphate leached from the soluble treated wood. Nano-ZnO was essentially non-leachable from wood treated with 5% formulation for the 30-nm particle size. In a no-choice laboratory test, eastern subterranean termites (Reticulitermes flavipes) consumed less than 10% of the leached nano-ZnO-treated wood with 93 to 100% mortality in all treatment concentrations. In contrast, termites consumed 10 to 12% of the leached ZnSO₄-treated wood, but with lower mortality: 29% in the 1% treatment group and less than 10% (5 and 8%, respectively) in the group of wood blocks treated with 2.5 and 5.0% ZnSO₄. We conclude that termites were repelled from consuming wood treated with nano-ZnO, but when consumed it was more toxic to eastern subterranean termites than wood treated with the soluble metal oxide formulation. There were no differences in leaching or termite mortality between the two particle sizes of nano-ZnO.     

Synthesis and Biochemical Evaluation of Biotinylated Conjugates of Largazole Analogues: Selective Class I Histone Deacetylase Inhibitors

The synthesis of biotinylated conjugates of synthetic analogues of the potent and selective histone deacetylase (HDAC) inhibitor largazole is reported. The thiazole moiety of the parent compound's cap group was derivatized to allow the chemical conjugation to biotin. The derivatized largazole analogues were assayed across a panel of HDACs 1–9 and retained potent and selective inhibitory activity towards the class I HDAC isoforms. The biotinylated conjugate was further shown to pull down HDACs 1, 2, and 3.     

Combined TPS, XPS, EXAFS, and NO-TPD study of the sulfiding of Mo/Al2O3

The sulfiding of Mo/Al₂O₃ in H₂S/Ar versus in H₂S/H₂ has been studied by temperature-programmed sulfiding (TPS), X-ray photon electron spectroscopy (XPS), extended X-ray absorption fine structure (EXAFS), and temperature-programmed desorption of NO (NO-TPD). All the applied techniques agree on the sulfur content in the sulfided catalysts and the findings are in accord with a model for the H₂S production reaction. The nucleation and growth of well-ordered MoS₂ clusters are probed by XPS during sulfiding with and without the presence of hydrogen. The resulting dispersion of the MoS₂ phase is evaluated on the basis of XPS, EXAFS, and NO-TPD, and is found to be highest when the sulfiding occurs in the presence of hydrogen.     

Fragment-Based Drug Discovery for RNA Targets

Rapid development within the fields of both fragment-based drug discovery (FBDD) and medicinal targeting of RNA provides possibilities for combining technologies and methods in novel ways. This review provides an overview of fragment-based screening (FBS) against RNA targets, including a discussion of the most recently used screening and hit validation methods such as NMR spectroscopy, X-ray crystallography, and virtual screening methods. A discussion of fragment library design based on research from small-molecule RNA binders provides an overview on both the currently limited guidelines within RNA-targeting fragment library design, and future possibilities. Finally, future perspectives are provided on screening and hit validation methods not yet used in combination with both fragment screening and RNA targets.     

Induction of Phenolic Glycosides by Quaking Aspen (<Emphasis Type=Italic>Populus tremuloides)</Emphasis> Leaves in Relation to Extrafloral Nectaries and Epidermal Leaf Mining

We studied the effect of epidermal leaf mining on the leaf chemistry of quaking aspen, Populus tremuloides, during an outbreak of the aspen leaf miner, Phyllocnistis populiella, in the boreal forest of interior Alaska. Phyllocnistis populiella feeds on the epidermal cells of P. tremuloides leaves. Eleven days after the onset of leaf mining, concentrations of the phenolic glycosides tremulacin and salicortin were significantly higher in aspen leaves that had received natural levels of leaf mining than in leaves sprayed with insecticide to reduce mining damage. In a second experiment, we examined the time course of induction in more detail. The levels of foliar phenolic glycosides in naturally mined ramets increased relative to the levels in insecticide-treated ramets on the ninth day following the onset of leaf mining. Induction occurred while some leaf miner larvae were still feeding and when leaves had sustained mining over 5% of the leaf surface. Leaves with extrafloral nectaries (EFNs) had significantly higher constitutive and induced levels of phenolic glycosides than leaves lacking EFNs, but there was no difference in the ability of leaves with and without EFNs to induce phenolic glycosides in response to mining. Previous work showed that the extent of leaf mining damage was negatively related to the total foliar phenolic glycoside concentration, suggesting that phenolic glycosides deter or reduce mining damage. The results presented here demonstrate that induction of phenolic glycosides can be triggered by relatively small amounts of mining damage confined to the epidermal tissue, and that these changes in leaf chemistry occur while a subset of leaf miners are still feeding within the leaf.     

Biomass gasification cogeneration – A review of state of the art technology and near future perspectives

Biomass is a renewable resource from which a broad variety of commodities can be produced. However, the resource is scarce and must be used with care to avoid depleting future stock possibilities. Flexibility and efficiency in production are key characteristics for biomass conversion technologies in future energy systems. Thermal gasification of biomass is proved throughout this article to be both highly flexible and efficient if used optimally. Cogeneration processes with production of heat-and-power, heat-power-and-fuel or heat-power-and-fertilizer are described and compared. The following gasification platforms are included in the assessment: The Harboøre up draft gasifier with gas engine, the Güssing FICFB gasifier with gas engine or PDU, the LT-CFB gasifier with steam cycle and nutrient recycling and finally the TwoStage down draft gasifier with gas engine, micro gas turbine (MGT), SOFC, SOFC/MGT or catalytic fuel synthesis.     

Perforation resistance of five different high-strength steel plates subjected to small-arms projectiles

Thin plates of high-strength steel are frequently being used both in civil and military ballistic protection systems. The choice of alloy is then a function of application, ballistic performance, weight and price. In this study the perforation resistance of five different high-strength steels has been determined and compared against each other. The considered alloys are Weldox 500E, Weldox 700E, Hardox 400, Domex Protect 500 and Armox 560T. The yield stress for Armox 560T is about three times the yield stress for Weldox 500E, while the opposite yields for the ductility. To certify the perforation resistance of the various targets, two different ballistic protection classes according to the European norm EN1063 have been considered. These are BR6 (7.62 mm Ball ammunition) and BR7 (7.62 mm AP ammunition), where the impact velocity of the bullet is about 830 m/s in both. Perforation tests have been carried out using adjusted ammunition to determine the ballistic limit of the various steels. In the tests, a target thickness of 6 mm and 6 + 6 = 12 mm was used for protection class BR6 and BR7, respectively. A material test programme was conducted for all steels to calibrate a modified Johnson–Cook constitutive relation and the Cockcroft–Latham fracture criterion, while material data for the bullets mainly were taken from the literature. Finally, results from 2D non-linear FE simulations with detailed models of the bullets are presented and the different findings are compared against each other. As will be shown, good agreement between the FE simulations and experimental data for the AP bullets is in general obtained, while it was difficult to get reliable FE results using the Lagrangian formulation of LS-DYNA for the soft core Ball bullet.