Catastrophic vs Gradual Collapse of Thin-Walled Nanocrystalline Ni Hollow Cylinders As Building Blocks of Microlattice Structures

Lightweight yet stiff and strong lattice structures are attractive for various engineering applications, such as cores of sandwich shells and components designed for impact mitigation. Recent breakthroughs in manufacturing enable efficient fabrication of hierarchically architected microlattices, with dimensional control spanning seven orders of magnitude in length scale. These materials have the potential to exploit desirable nanoscale-size effects in a macroscopic structure, as long as their mechanical behavior at each appropriate scale – nano, micro, and macro levels – is properly understood. In this letter, we report the nanomechanical response of individual microlattice members. We show that hollow nanocrystalline Ni cylinders differing only in wall thicknesses, 500 and 150 nm, exhibit strikingly different collapse modes: the 500 nm sample collapses in a brittle manner, via a single strain burst, while the 150 nm sample shows a gradual collapse, via a series of small and discrete strain bursts. Further, compressive strength in 150 nm sample is 99.2% lower than predicted by shell buckling theory, likely due to localized buckling and fracture events observed during in situ compression experiments. We attribute this difference to the size-induced transition in deformation behavior, unique to nanoscale, and discuss it in the framework of “size effects” in crystalline strength

Cross-resistance of rice flatsedge to ALS-inhibiting herbicides.

This study aimed to evaluate the crossresistance of CYPIR to ALS-inhibiting herbicides in irrigated rice in Rio Grande do Sul.e017166827

Structures and functions of mitochondrial ABC transporters

A small number of physiologically important ATP-binding cassette (ABC) transporters are found in mitochondria. Most are half transporters of the B group forming homodimers and their topology suggests they function as exporters. The results of mutant studies point towards involvement in iron cofactor biosynthesis. In particular, ABC subfamily B member 7 (ABCB7) and its homologues in yeast and plants are required for iron-sulfur (Fe-S) cluster biosynthesis outside of the mitochondria, whereas ABCB10 is involved in haem biosynthesis. They also play a role in preventing oxidative stress. Mutations in ABCB6 and ABCB7 have been linked to human disease. Recent crystal structures of yeast Atm1 and human ABCB10 have been key to identifying substrate-binding sites and transport mechanisms. Combined with in vitro and in vivo studies, progress is being made to find the physiological substrates of the different mitochondrial ABC transporters

Mutagenesis separates ATPase and thioesterase activities of the peroxisomal ABC transporter, Comatose

The peroxisomal ABC transporter, Comatose (CTS), a full length transporter from Arabidopsis has intrinsic acyl-CoA thioesterase (ACOT) activity, important for physiological function. We used molecular modelling, mutagenesis and biochemical analysis to identify amino acid residues important for ACOT activity. D863, Q864 and T867 lie within transmembrane helix 9. These residues are orientated such that they might plausibly contribute to a catalytic triad similar to type II Hotdog fold thioesterases. When expressed in Saccharomyces cerevisiae, mutation of these residues to alanine resulted in defective of β-oxidation. All CTS mutants were expressed and targeted to peroxisomes and retained substrate-stimulated ATPase activity. When expressed in insect cell membranes, Q864A and S810N had similar ATPase activity to wild type but greatly reduced ACOT activity, whereas the Walker A mutant K487A had greatly reduced ATPase and no ATP-dependent ACOT activity. In wild type CTS, ATPase but not ACOT was stimulated by non-cleavable C14 ether-CoA. ACOT activity was stimulated by ATP but not by non-hydrolysable AMPPNP. Thus, ACOT activity depends on functional ATPase activity but not vice versa, and these two activities can be separated by mutagenesis. Whether D863, Q864 and T867 have a catalytic role or play a more indirect role in NBD-TMD communication is discussed

Retinal horizontal cells use different synaptic sites for global feedforward and local feedback signaling

In the outer plexiform layer (OPL) of the mouse retina, two types of cone photoreceptors (cones) provide input to more than a dozen types of cone bipolar cells (CBCs). This transmission is modulated by a single horizontal cell (HC) type, the only interneuron in the outer retina. Horizontal cells form feedback synapses with cones and feedforward synapses with CBCs. However, the exact computational role of HCs is still debated. Along with performing global signaling within their laterally coupled network, HCs also provide local, cone-specific feedback. Specifically, it has not been clear which synaptic structures HCs use to provide local feedback to cones and global forward signaling to CBCs. Here, we reconstructed in a serial block-face electron microscopy volume the dendritic trees of five HCs as well as cone axon terminals and CBC dendrites to quantitatively analyze their connectivity. In addition to the fine HC dendritic tips invaginating cone axon terminals, we also identified “bulbs”, short segments of increased dendritic diameter on the primary dendrites of HCs. These bulbs are located well below the cone axon terminal base and make contact to other cells mostly identified as other HCs or CBCs. Using immunolabeling we show that HC bulbs express vesicular gamma-aminobutyric acid transporters and co-localize with GABA receptor γ2 subunits. Together, this suggests the existence of two synaptic strata in the mouse OPL, spatially separating cone-specific feedback and feedforward signaling to CBCs. A biophysics-based computational model of a HC dendritic branch supports the hypothesis that the spatial arrangement of synaptic contacts allows simultaneous local feedback and global feedforward signaling

Alternativas de controle químico de junquinho resistente aos herbicidas inibidores da als.

Cyperus iria L. (CYPIR) é uma das principais ciperáceas ocorrentes em lavouras de arroz irrigado. Durante muitos anos, os herbicidas inibidores da enzima acetolactato sintase (ALS) foram a principal ferramenta para controle de CYPIR, favorecendo a seleção de biótipos com resistência cruzada. Com base no nível de resistência, é necessária a adoção de medidas de controle químico alternativo a fim de evitar a evolução da resistência e reduzir a interferência sobre a cultura. O objetivo desse trabalho foi avaliar alternativas de controle químico de CYPIR com resistência cruzada aos herbicidas inibidores da ALS, ocorrente em lavouras de arroz irrigado no Sul do Brasil. Dois experimentos foram conduzidos em casa de vegetação, em delineamento inteiramente casualizado com quatro repetições. Os herbicidas utilizados foram: imazethapyr; formulação de imazapyr+imazapic; bentazon; propanil; formulação de bentazon+imazamox; mistura de (bentazone + imazamox) + (imazapyr + imazapic); associação de bentazone + formulação de (imazapyr + imazapic); glyphosate; e testemunha sem herbicida. A avaliação do controle foi realizada em biótipo resistente (CYPIR-R) e suscetível (CYPIR-S), e a fitotoxicidade avaliada nas cultivares Guri Inta CL, IRGA 424 RI e IRGA 409. Aos 28 dias após aplicação (DAA) foi avaliado o controle/ fitotoxicidade e a matéria seca da parte aérea (MSPA). Todos os tratamentos testados, com exceção do imazethapyr e formulação de imazapyr+imazapic isolados, foram eficientes. Há alternativas para o controle químico de Cyperus iria resistente aos inibidores da ALS e esses, quando associados com produtos que apresentam mecanismo de ação diferentes, não inviabilizam o uso da tecnologia ClearField®.Cyperus iria L. (CYPIR) is one of the main cyperaceae occurring in irrigated rice crop. For many years, acetolactate synthase inhibitor herbicides (ALS) were the main tool to control CYPIR, favoring the selection of cross-resistance biotypes. Based on the level of resistance, it is necessary to adopt alternative chemical control measures in order to avoid the evolution of the resistance and to reduce the interference on the crop. The aim of this work was to evaluate alternatives of chemical control of CYPIR to ALS-inhibiting herbicides, occurring in irrigated rice crops in southern Brazil. There were conducted two experiments in greenhouse, arranged in completely randomized design with four replicates. The herbicides used were: imazethapyr; imazapyr+imazapic formulation; bentazon; propanil; formulation of bentazon+imazamox; mixture of (bentazone + imazamox) + (imazapyr + imazapic); association of bentazone + (imazapyr + imazapic); glyphosate; and control without herbicide. The control evaluation was performed in a resistant (CYPIR-S) and susceptible (CYPIR-S) biotype, and the phytotoxicity evaluated in the Guri Inta CL, IRGA 424 RI and IRGA 409 cultivars. At 28 days after application (DAA) the control / phytotoxicity and shoot dry matter (SDM) were evaluated. All treatments tested, except for imazethapyr and imazapyr+imazapic applied in isolation, were efficient. There are alternatives to the chemical control of Cyperus iria resistant to ALS-inhibiting herbicides and these, when associated with products that have different mechanisms of action, do not impair the use of ClearField® technology

Individual and integrated methods on tough lovegrass control.

ABSTRACT: The current study evaluated the efficiency of mechanical, physical, chemical and cultural methods, used exclusively or integrated, to control tough lovegrass. The experimental design was completely randomized, with 15 treatments and four repetitions. Physical control of tough lovegrass was based on the application of fire, whereas mechanical controls consisted in mowing and harrowing/plowing procedures. The herbicide clethodim and different glyphosate salts were evaluated for chemical control. Glyphosate and soil fertility correction were applied as cultural and integrated methods, in addition to isopropylamine + potassium salts combination, soil fertility correction and implantation of one of the following forage plants: Elephant grass, Pangola grass, Forage peanut and Birdsfoot trefoil. The effect of treatments on the incidence of tough lovegrass and on its botanical composition was evaluated one year after their applications. Isolated control methods, except for glyphosate using, did not present efficient tough lovegrass control. Glyphosate salts could control tough lovegrass plants, but their association with improved soil fertility and Pangola grass implantation was the best strategy to control the invasive plant. Key words: Eragrostis plana Nees, native pasture, weed control

Integrated management of tough lovegrass (Eragrostis plana Nees): associating chemical control tools and plant physiology.

ABSTRACT:The objective of the study was to evaluate the efficiency of herbicides use in the control of tough lovegrass according to the availability of solar radiation and the presence or absence of flooded. Two experiments were conducted in a completely randomized design, in a 2x2x4 and 2x2x5 factorial scheme, where factor A was equivalent to the environment (natural or reduced radiation); factor B to water condition (with a 2 cm flooded or without); and, factor C the herbicides: cyhalofop butyl (315 g ha-1), glyphosate (1080 g ha-1), cyhalofop butyl + glyphosate (315 g ha-1 + 1080 g ha-1) and control (without application) in the first experiment. In the second experiment, the herbicides used were cyhalofop butyl (315 g ha-1), glyphosate (1080 g ha-1), sethoxydim (184g ha-1), imazethapyr (106 g ha-1) and control (without application). Glyphosate efficiently controls plants of tough lovegrass with four tillers (>90%), being superior to cyhalofop, imazethapyr and sethoxydim; independently, of resource conditions. Reduction in the availability of solar radiation generates less shoot dry mass production from the weed, and improves the control only by imazethapyr and cyhalofop. In general, a flooded condition does not affect tough lovegrass control by herbicides.Key words: flooded, glyphosate, pasture, shading, weed control. Manejo integrado de capim-annoni (Eragrostis plana Nees): associando ferramentas do controle químico e fisiologia da planta RESUMO:O objetivo do trabalho foi avaliar a eficiência de uso de herbicidas no controle de capim-annoni em função da disponibilidade de radiação solar e da presença ou ausência de lâmina de água. Para isso, foram conduzidos dois experimentos em delineamento inteiramente casualizado, em esquema fatorial 2x2x4 e 2x2x5, em que o fator A equivaleu ao ambiente (radiação natural ou reduzida); fator B à condição hídrica (com lâmina d?água de 2 cm ou sem); e, o fator C aos herbicidas: cyhalofop butyl (315 g ha-1), glyphosate (1080 g ha-1), cyhalofop butyl + glyphosate (315 g ha-1 + 1080 g ha-1) e testemunha (sem aplicação) no primeiro experimento. No segundo experimento, os herbicidas utilizados foram: cyhalofop butyl (315 g ha-1), glyphosate (1080 g ha-1), sethoxydim (184 g ha-1), imazethapyr (106 g ha-1) e testemunha (sem aplicação). Glyphosate controla eficientemente plantas de capim-annoni com quatro afilhos (>90%), sendo superior a cyhalofop butyl, imazethapyr e sethoxydim, independente das condições. A redução da disponibilidade de radiação solar gera menor produção de matéria seca da parte aérea pelo capim-annoni, podendo inclusive, contribuir para maior eficiência de controle somente por imazethapyr e cyhalofop. De maneira geral, a condição de lâmina d?água não afeta o controle de capim-annoni pelos herbicidas.Palavras-chave: lâmina d ́água, glifosato, pastagem, sombreamento, controle de pla

Interleukin-17D and Nrf2 mediate initial innate immune cell recruitment and restrict MCMV infection.

Innate immune cells quickly infiltrate the site of pathogen entry and not only stave off infection but also initiate antigen presentation and promote adaptive immunity. The recruitment of innate leukocytes has been well studied in the context of extracellular bacterial and fungal infection but less during viral infections. We have recently shown that the understudied cytokine Interleukin (IL)-17D can mediate neutrophil, natural killer (NK) cell and monocyte infiltration in sterile inflammation and cancer. Herein, we show that early immune cell accumulation at the peritoneal site of infection by mouse cytomegalovirus (MCMV) is mediated by IL-17D. Mice deficient in IL-17D or the transcription factor Nuclear factor (erythroid-derived 2)-like 2 (Nrf2), an inducer of IL-17D, featured an early decreased number of innate immune cells at the point of viral entry and were more susceptible to MCMV infection. Interestingly, we were able to artificially induce innate leukocyte infiltration by applying the Nrf2 activator tert-butylhydroquinone (tBHQ), which rendered mice less susceptible to MCMV infection. Our results implicate the Nrf2/IL-17D axis as a sensor of viral infection and suggest therapeutic benefit in boosting this pathway to promote innate antiviral responses