Correlative microscopy for structural microbiology

Microscopic imaging and technolog

Microfluidic synthesis of monodisperse and size-tunable CsPbBr3 supraparticles

The highly controlled, microfluidic template-assisted self-assembly of CsPbBr3 nanocrystals into spherical supraparticles is presented, achieving precise control over average supraparticle size through the variation of nanocrystal concentration and droplet size; thus facilitating the synthesis of highly monodisperse, sub-micron supraparticles (with diameters between 280 and 700 nm)

Structures of C1-IgG1 provide insights into how danger pattern recognition activates complement

Microscopic imaging and technolog

State of the world’s plants and fungi 2020

Kew’s State of the World’s Plants and Fungi project provides assessments of our current knowledge of the diversity of plants and fungi on Earth, the global threats that they face, and the policies to safeguard them. Produced in conjunction with an international scientific symposium, Kew’s State of the World’s Plants and Fungi sets an important international standard from which we can annually track trends in the global status of plant and fungal diversity

Testing a potential mantle geohygrometer; the effect of dissolved water on the intracrystalline partitioning of Al in orthopyroxene

The presence of water in the Earth's mantle has wide ranging implications and a detailed picture of the spatial and temporal distribution of water in the mantle is needed to be able to understand fundamental global-scale processes. However the interpretation of measured water concentrations in nominally anhydrous minerals (NAMs) from xenoliths or magmatic phenocrysts is complicated by fast diffusion of H and hence the probability of hydration or dehydration during ascent. Rauch and Keppler [1]M. Rauch, H. Keppler, Water solubility in orthopyroxene, Contrib. Mineral. Petrol. 143 (2002) 525-536 have proposed that the partitioning of Al between octahedral and tetrahedral sites in orthopyroxene has the potential to be used as a more reliable mantle geohygrometer than direct measurements of water concentrations in xenolith minerals. In the present study, we have tested the theoretical basis for this geohygrometer by experimentally producing aluminous orthopyroxene samples and measuring the intracrystalline partitioning of Al using very high-field 27Al magic angle spinning nuclear magnetic resonance. In both dry and hydrous orthopyroxene, aluminium is shown to be incorporated by a Tschermak's substitution (one tetrahedral and one octahedral Al), thus the incorporation mechanism of Al in orthopyroxene is not a valid basis for a geohygrometer. However, the effect of OH on the local environment of Al has been observed, and quantification of all the different types of Al in the hydrous samples suggests that OH is incorporated by protonation of O21 and O22 sites. The results suggest that NMR studies on nuclei other than 1H offer new possibilities for studying the interaction of water with mantle minerals. © 2005 Elsevier B.V. All rights reserved

Astrophysical Gyrokinetics: Kinetic and Fluid Turbulent Cascades In Magentized Weakly Collisional Plasmas

This paper presents a theoretical framework for understanding plasma turbulence in astrophysical plasmas. It is motivated by observations of electromagnetic and density fluctuations in the solar wind, interstellar medium and galaxy clusters, as well as by models of particle heating in accretion disks. All of these plasmas and many others have turbulentmotions at weakly collisional and collisionless scales. The paper focuses on turbulence in a strong mean magnetic field. The key assumptions are that the turbulent fluctuations are small compared to the mean field, spatially anisotropic with respect to it and that their frequency is low compared to the ion cyclotron frequency. The turbulence is assumed to be forced at some system-specific outer scale. The energy injected at this scale has to be dissipated into heat, which ultimately cannot be accomplished without collisions. A kinetic cascade develops that brings the energy to collisional scales both in space and velocity. The nature of the kinetic cascade in various scale ranges depends on the physics of plasma fluctuations that exist there. There are four special scales that separate physically distinct regimes: the electron and ion gyroscales, the mean free path and the electron diffusion scale. In each of the scale ranges separated by these scales, the fully kinetic problem is systematically reduced to a more physically transparent and computationally tractable system of equations, which are derived in a rigorous way. In the "inertial range" above the ion gyroscale, the kinetic cascade separates into two parts: a cascade of Alfvenic fluctuations and a passive cascade of density and magnetic-fieldstrength fluctuations. The former are governed by the Reduced Magnetohydrodynamic (RMHD) equations at both the collisional and collisionless scales; the latter obey a linear kinetic equation along the (moving) field lines associated with the Alfvenic component (in the collisional limit, these compressive fluctuations become the slow and entropy modes of the conventional MHD). In the "dissipation range" below ion gyroscale, there are again two cascades: the kinetic-Alfven-wave (KAW) cascade governed by two fluid-like Electron Reduced Magnetohydrodynamic (ERMHD) equations and a passive cascade of ion entropy fluctuations both in space and velocity. The latter cascade brings the energy of the inertial-range fluctuations that was Landau-damped at the ion gyroscale to collisional scales in the phase space and leads to ion heating. The KAWenergy is similarly damped at the electron gyroscale and converted into electron heat. Kolmogorov-style scaling relations are derived for all of these cascades. The relationship between the theoretical models proposed in this paper and astrophysical applications and observations is discussed in detail

Structures of C1-IgG1 provide insights into how danger pattern recognition activates complement

Danger patterns on microbes or damaged host cells bind and activate C1, inducing innate immune responses and clearance through the complement cascade. How these patterns trigger complement initiation remains elusive. Here, we present cryo–electron microscopy analyses of C1 bound to monoclonal antibodies in which we observed heterogeneous structures of single and clustered C1–immunoglobulin G1 (IgG1) hexamer complexes. Distinct C1q binding sites are observed on the two Fc-CH2 domains of each IgG molecule. These are consistent with known interactions and also reveal additional interactions, which are supported by functional IgG1-mutant analysis. Upon antibody binding, the C1q arms condense, inducing rearrangements of the C1r2s2 proteases and tilting C1q’s cone-shaped stalk. The data suggest that C1r may activate C1s within single, strained C1 complexes or between neighboring C1 complexes on surfaces

Digestibilidade Aparente da Proteína Bruta e dos Componentes da Parede Celular de uma Ração Completa, com Bovinos de Diferentes Grupos Genéticos Apparent Digestibility of Crude Protein and Cell Wall Components of a Total Ration Fed to Bovines of Different Genetic Groups

Avaliaram-se os coeficientes de digestibilidade do extrato etéreo (EE), proteína bruta (PB), fibra em detergente neutro (FDN), fibra em detergente ácido (FDA), hemicelulose (HCEL) e celulose (CEL) de uma ração completa, composta por 44,3% de feno de braquiária, 55% de concentrado e 0,7% de mistura mineral, fornecida a bovinos de diferentes grupos genéticos (Gir, Nelore, Guzerá, Santa Gertrudis e Caracu), pelas metodologias de coleta total de fezes e com indicador interno (lignina em detergente ácido - LDA), em delineamento inteiramente casualizado, com três repetições por grupo genético, com análise de variância individual dentro de cada metodologia e uma análise de correlação entre as metodologias. Não houve diferença entre grupos genéticos para a digestibilidade de EE, PB, FDN, FDA, HCEL e CEL, pelas metodologias de coleta total de fezes e com LDA, com médias de 44,28 e 40,38%; 52,46 e 49,51%; 57,04 e 54,25%; 37,71 e 34,04%; 71,66 e 69,68%; e 48,27 e 45,20%, respectivamente. As digestibilidades da PB, FDA e CEL não mostraram correlação. A LDA foi eficiente na estimativa da digestibilidades e os nutrientes foram utilizados de forma semelhante pelos diferentes grupos genéticos.<br>The digestibility of ether extract (EE), crude protein (CP), neutral detergent fiber (NDF), acid detergent fiber (ADF), hemicellulose (HCEL) and cellulose (CEL) of a total ration was evaluated. The ration, composed by 44.3% Brachiaria hay, 55% concentrate and 0.7% mineral mixture, was fed to animals of different genetic groups (Gyr, Nellore, Guzera, Santa Gertrudis and Caracu), using total feces collection and internal marker (acid detergent lignin - ADL). The data were analyzed in a completely randomized design, with three replications for genetic group, with analysis of variance for both technique and correlation analysis between them. There were no differences among genetic groups for digestibility of EE, CP, NDF, ADF, HCEL and CEL using total feces collection and ADL, with averages of 44.28% and 40.38%; 52.46% and 49.51%; 57.04% and 54.25%; 37.71% and 34.04%; 71.66% and 69.68%; 48.27% and 45.20%, respectively. Digestibility for CP, ADF and CEL did not show correlation. ADL was efficient to estimate digestibility, and nutrients were used in a similar way for the different genetic groups