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Even when environments deteriorate gradually, ecosystems may shift abruptly from one state to another. Such catastrophic shifts are difficult to predict and reverse (hysteresis). While well studied in simplified contexts, we lack a general understanding of how catastrophic shifts spread in realistic spatial contexts. For different types of landscape structure, including typical terrestrial modular and riverine dendritic networks, we here investigate landscape-scale stability in metapopulations made of bistable patches. We find that such metapopulations usually exhibit large scale catastrophic shifts and hysteresis, and that the properties of these shifts depend strongly on metapopulation spatial structure and dispersal rate: intermediate dispersal rates and a riverine spatial structure can largely reduce hysteresis size. Interestingly, our study suggests that large-scale restoration is easier with spatially clustered restoration efforts and in populations characterized by an intermediate dispersal rate.

The subcutaneous mechanical response of the fingertip is highly anisotropic due to the presence of a network of collagen fibers linking the outer skin layer to the bone. Yet, the impact of this anisotropy on the fingerpad deformation had not been studied until now. This issue is here tackled using a two-dimensional finite element model of a transverse section of the finger. Different hypotheses about the orientation of the fibers are considered: radial (physiologic), circumferential, and random (isotropic behavior). The three variants of the model are assessed using experimental observations of a finger leaning on a flat surface. Predictions relying on the physiological orientation of fibers align best with reality. Moreover, the orientation of fibers plays a crucial role in determining the distribution of internal strain and stress. These factors, combined with the abrupt shift in contact pressure during the transition from sticking to slipping, represent important sensory cues for partial slip detection. This is valuable information for the development of haptic devices.

Surface skin deformation of the finger pad during partial slippage at finger–object interfaces elicits firing of the tactile sensory afferents. A torque around the contact normal is often present during object manipulation, which can cause partial rotational slippage. Until now, studies of surface skin deformation have used stimuli sliding rectilinearly and tangentially to the skin. Here, we study surface skin dynamics under pure torsion of the right index finger of seven adult participants (four males). A custom robotic platform stimulated the finger pad with a flat clean glass surface, controlling the normal forces and rotation speeds applied while monitoring the contact interface using optical imaging. We tested normal forces between 0.5 N and 10 N at a fixed angular velocity of 20° s −1 and angular velocities between 5° s −1 and 100° s −1 at a fixed normal force of 2 N. We observe the characteristic pattern by which partial slips develop, starting at the periphery of the contact and propagating towards its centre, and the resulting surface strains. The 20-fold range of normal forces and angular velocities used highlights the effect of those parameters on the resulting torque and skin strains. Increasing normal force increases the contact area, the generated torque, strains and the twist angle required to reach full slip. On the other hand, increasing angular velocity causes more loss of contact at the periphery and higher strain rates (although it has no impact on resulting strains after the full rotation). We also discuss the surprisingly large inter-individual variability in skin biomechanics, notably observed in the twist angle the stimulus needs to rotate before reaching full slip.

The effects of adding surfactants to polyurethane and resorcinol formaldehyde adhesives were tested relative to the gluability of spotted gum timber for structural glue-laminated beams (Glulam). While previous attempts to improve the bond performance of this very difficult to glue timber have focused primarily on timber surface preparations, this study concentrated on lowering the adhesive surface tension through added surfactants to improve the adhesive-timber surface wetting. Accordingly, 44 glulam samples were manufactured using polyurethane and resorcinol formaldehyde adhesives, with eight surfactant formulations and two different pre-gluing surface machining methods, i.e., face milling and planing. Although the surfactants were successful in drastically lowering the adhesive surface tension and improving adhesive spreading, none of the surfactant formulations tested were successful in improving the glulam adhesive bond qualities. Overall, the surfactant formulations produced considerably higher delamination, lower shear strength, and lower wood fibre failure compared to the control samples; therefore, they are not a viable solution to improve the gluing of spotted gum. The resorcinol formaldehyde adhesive and face milling produced considerably better results compared to the polyurethane adhesives and conventional planing.

The punching and post-punching shear behaviours of reinforced concrete (RC) flat plate structures are often studied by using a representative slab–column connection isolated from the parent structure. In this study, a set of numerical modelling techniques is established to create a competent three-dimensional non-linear model to simulate punching and post-punching shear behaviours of RC slab–column connections without shear reinforcement, through the use of which the punching shear failure featuring a critical punching shear surface and an abrupt drop of the applied force in the load–displacement response is able to be accurately reproduced. The post-punching shear behaviour, taking the form of an increased load-carrying capacity which is ceased by rebar fracture in the suspension stage, is also well captured. Using the proposed numerical model, typical punching and post-punching shear failure mechanisms are studied in some detail.

During active object manipulation, the finger-object interactions give rise to complex fingertip skin deformations. These deformations are in turn encoded by the local tactile afferents and provide rich and behaviorally relevant information to the central nervous system. Most of the work studying the mechanical response of the finger to dynamic loading has been performed under a passive setup, thereby precisely controlling the kinematics or the dynamics of the loading. However, to identify aspects of the deformations that are relevant to online control during object manipulation, it is desirable to measure the skin response in an active setup. To that end, we developed a device that allows us to monitor finger forces, skin deformations, and kinematics during fine manipulation. We describe the device in detail and test it to precisely describe how the fingertip skin in contact with the object deforms during a simple vertical oscillation task. We show that the level of grip force directly influences the fingerpad skin strains and that the strain rates are substantial during active manipulation (norm up to 100%/s). The developed setup will enable us to causally relate sensory information, i.e. skin deformation, to online control, i.e. grip force adjustment, in future studies.

Surface skin deformation of the finger pad during partial slippage at finger-object interfaces elicits tactile feedback. During object manipulation, torque is often present, which can cause partial slippage. Until now, studies of surface skin deformation have used stimuli sliding on rectilinear tangential trajectories.Here we studied surface skin dynamics under torsion. A custom robotic platform stimulated the finger pad with a flat transparent surface, controlling the normal forces and rotation speeds applied while monitoring the contact interface using optical imaging.We observed the characteristic pattern by which partial slips develop, starting at the periphery of the contact and propagating towards its centre, and the resulting surface strains. The 20-fold range of normal forces and angular velocities used highlights the effect of those parameters on the resulting torque and skin strains. While normal force increases the contact area, generated torque, strains, and twist angle required to reach full slip, angular velocity increases loss of contact at the periphery and strain rates (although not total strains). We also discuss the surprisingly large inter-individual variability in skin biomechanics, notably observed in the twist angle the stimulus needed to rotate before reaching full slip.

Occupying a substantial proportion of the overall building expense, building envelopes are the subject of ongoing research and improvement in both aesthetic and structural aspects. The aluminium window wall frame, consisting of vertical members (mullions) and horizontal members (head and sill transoms), is placed between sub-heads at the top and sub-sills at the bottom of the wall. These window walls are designed to carry lateral wind loads. Of particular importance to design stability is the bearing behaviour of aluminium sub-heads. The bearing behaviour and capacities of C-shaped sub-heads were recently investigated through a detailed experimental study at Griffith University for the development of strength prediction equations. To allow for easier assembly of facade panels, a kind of sub-head section known as sub-head with removable bead is used in aluminium window wall system. Two parts of this sub-head are connected together without any external mechanisms. The present research places emphasis on assessing the bearing behaviour of aluminium sub-heads with removable beads through comprehensive experimental testing. A total of 36 tests were conducted using six section geometries, two engagement lengths, and three bearing widths. The bearing strengths obtained from tests of aluminium sub-heads with removable beads were compared with the bearing capacities predicted using the design rules developed by the authors for conventional C-shaped aluminium sub-heads and available cold-formed steel design provisions (AISI S240 2015, TI 809-07, and SSMA 2000 specifications). As a result of the investigation, the current design equations were found to be unreliable for estimating the bearing capacity of aluminium sub-head sections with removable beads. Hence, new design expressions have been developed which accurately predict the strengths of aluminium sub-heads with removable beads under out-of-plane loads. Furthermore, the influence of the removable beads on the bearing behaviour and capacity is discussed in detail.

Nailplates are widely used in domestic and low-rise residential housing markets and have begun forming part of mid-rise developments. There is however a concern about nailplates backing out which has been observed in a variety of conditions. In-service backouts in excess of 2 mm have been recorded and can result in up to a 50 % reduction in joint performance. The amount of backout varies significantly from roof space to roof space and the physical phenomena leading to backout and their exact relationship to the climatic conditions are largely unknown. This paper experimentally investigates the time dependent backout mechanisms and develops a numerical model to predict the range of backouts that will be expected from a set of climatic conditions that the nailplates would be exposed to. Specifically, this paper initially investigates the backout of single nails, representative of nailplate teeth, by pressing the nails into pieces of timber and subjecting the samples to cyclic climatic conditions. The moisture driven backout of the nails was monitored in real-time using Digital Image Correlation for 48 days. Backouts of between 0.08 and 0.26 mm were observed. Results showed that during the drying phase, the timber surface tended to slide along the surface of the nail. A similar phenomenon was observed during the wetting phase but to a lower extent. This consequently led to a ratcheting mechanism that caused the nail to backout from the timber. A numerical model is then proposed to predict and replicate the time dependent backout behaviour of the nailplate tooth based on heat and mass transfer algorithm TransPore and Finite Element Software ABAQUS. The model was validated against the experimental results based on the timber properties and climatic conditions that the timber was exposed to. The model was able to accurately predict the time-dependent backout of the nails. To illustrate the application of the model, the expected nailplate backout for two different Australian roof spaces was investigated. A variety of parameters was investigated including the length and position of the tooth. It was found that longer teeth experienced higher rates of backout and significant variations in backout were encountered whether the tooth is closer to the edge or the middle of the timber.

SUMMARY2-hydroxyglutarate (2HG) is a by-product of the TCA cycle, and is readily detected in the tissues of healthy individuals. 2HG is found in two enantiomeric forms: S-2HG and R-2HG. Here, we investigate the differential roles of these two enantiomers in CD8+ T cell biology, where we found they had highly divergent effects on proliferation, differentiation, and T cell function. We show here an analysis of structural determinants that likely underlie these differential effects on specific a-ketoglutarate (aKG)-dependent enzymes. Treatment of CD8+ T cells with exogenous S-2HG, but not R-2HG, increased CD8+ T cell fitness in vivo, and enhanced anti-tumour activity. These data show that S-2HG and R-2HG should be considered as two distinct and important actors in the regulation of T cell function.

Potent T cell responses against infections and malignancies depend on the release of effector molecules, such as pro-inflammatory cytokines. Because effector molecules can be toxic, their production is tightly regulated through post-transcriptional events at 3’ Untranslated Regions (3’UTRs). RNA binding proteins (RBPs) were shown to be key regulators herein. With an RNA aptamer-based capture assay from human T cells, we identified >130 RBPs interacting with theIFNG, TNFandIL23’UTRs in human T cells. T cell activation altered RBP-RNA interactions, revealing that RBP-target mRNA interactions rapidly respond to stimulation. Furthermore, we uncovered the intricate and time-dependent regulation of cytokine production by RBPs: whereas HuR supports early cytokine production, ZFP36L1, ATXN2L and ZC3HAV1 dampen and shorten the production duration, each at different time points. Strikingly, even though ZFP36L1 deletion did not phenotypically rescue T cell dysfunction in tumors, the increased production of cytokines and cytotoxic molecules resulted in superior anti-tumoral T cell responsesin vivo. Our findings thus show that identifying RBP-RNA interactions reveals key modulators of T cell responses in health and disease.

Laboratory-based research is resource intensive in terms of financial costs and its carbon footprint. Research laboratories require immense amounts of energy to power equipment, as well as large volumes of materials, particularly of single-use item consumption. In fact, many laboratories have essentially become reliant on single-use plastics. Understanding the full carbon footprint of consumable usage is increasingly important as many research institutes commit to carbon neutrality. To date, no carbon footprint assessment has been conducted to detail the differences between single-use plastics, and reusable glass in a laboratory setting. Here, we analyse the CO2 equivalent (CO2e) footprint of utilising single-use plastics, and re-use of glass or plastic items within laboratory environments. We focused our assessment on four commonly utilised consumables for mammalian cell and bacterial culture, and found that re-use scenarios resulted in substantial reduction in CO2e footprint up to 11-fold. In addition, we estimated the long-term financial costs of re-use and single-use scenarios, and found that re-use had either similar or much lower running costs even when including technical staff wage. We concluded that research facilities must foster re-use in laboratory consumables, while reserving single-use items for select, defined cases. Our study highlights the need to account for indirect CO2e footprint in designing a carbon-neutral lab and promotes circular economy principles.

Novel light timber sandwich panels (referred to as BCS panels herein) are manufactured by gluing plywood faces to bamboo core rings. The panels are tested in compression and in bonding shear (between bamboo and plywood). A finite element model is developed and validated against the experimental results, and is used to capture the responses of the BCS panels under axial and combined axial and bending actions. A lognormal distribution is used to represent the mechanical properties of plywood in the finite element analyses (FEA). Moreover, effect of different core configurations, face thickness, core layers and initial imperfection shapes on the axial compressive capacity of the panels are investigated. Where possible, results are compared against theoretical predictions. Current test results show that under axial compressive action, the ultimate capacity to weight ratio of the BCS panels are up to 27.3% higher than a conventional CLT panel of the same dimension. At large slenderness ratios, the proposed BCS panels have ultimate axial capacities close to the conventional CLT panels. Under combined axial and bending loading, the BCS panels outperform a CLT panel of similar size.

Made available in DSpace on 2020-12-12T01:15:00Z (GMT). No. of bitstreams: 0 Previous issue date: 2020-06-01 Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) The challenge to obtain stable glasses containing monodisperse magnetic nanoparticles with controlled size and shape is an exciting and almost unexplored field of research. Such new materials can be used in magneto-photonics or ultra-sensitive magnetic sensors. In this work, for the first time, colorless and transparent bulk glasses containing monodisperse 20 nm Fe3−δO4 nanoparticles were prepared by a melt-quenching route. Magnetic nanoparticles were synthesized by thermal decomposition and covered with a stellate mesoporous silica shell in order to protect them against dissolution during the glass melting process. The incorporation of nanoparticles into glasses and the ideal parameters obtained for this system are discussed. The new nanocomposite materials were characterized in order to investigate the structure, thermal, and magnetic properties. Such an original approach is a very promising way to incorporate a wide panel of nanoparticles, including metallic, bimetallic and metal oxide nanoparticles, into a variety of glasses providing new properties to these materials. São Paulo State University - UNESP Institute of Chemistry, P. O. Box 355 Université de Strasbourg CNRS Institut de Physique et Chimie des Matériaux de Strasbourg UMR 7504 São Paulo State University - UNESP Institute of Chemistry, P. O. Box 355 CNPq: 153762/2018-7 FAPESP: 2013/07793-6 FAPESP: 2018/07727-7 FAPESP: 2019/19609-1 CAPES: 88881.134870/2016-01

This paper experimentally evaluates the embedment strength of laminated veneer lumbers (LVL) and cross-banded laminated veneer lumbers (LVL-C) manufactured from blending spotted gum (Corymbia citriodora) or white cypress pine (Callitris glaucophylla) veneers with hoop pine (Araucaria cunninghamii) veneers. Nominal 3.0 mm thick veneers were rotary peeled from small diameter (less than 30 cm) native forest sourced spotted gum and white cypress pine logs, and plantation grown hoop pine logs. 12-ply × 1.2 m (long) × 0.9 m (wide) LVL and LVL-C panels were manufactured using ten different construction strategies by mixing (i) the number of veneers from each species, (ii) the modulus of elasticity of the veneers and (iii) the veneer orientations (cross-banding). A total of 672 embedment tests, using three different dowel diameters and four different load-to-grain orientation angles, were performed using the half-hole test method described in the ASTM D5764-97a. This paper (i) compares the proportional limit strength, 5%-offset embedment strength and maximum embedment strength across the different construction strategies adopted in the study, and (ii) discusses the results in terms of load-to-grain angle and dowel diameter. More importantly, the test results are also compared to the embedment strength prediction equations detailed in the Eurocode 5 to determine their suitability for mixed-species LVL and LVL-C products. Overall, the mixed-species LVL and LVL-C showed significantly higher 5%-offset embedment strengths than single-species commercial softwood LVL products. The effect of the cross-banded veneers on the embedment strength was not found to be significant. However, the LVL-C samples exhibited a highly ductile behaviour for all load-to-grain angles and dowel diameters when compared to the LVL samples. The experimentally determined 5%-offset and maximum embedment strengths for the mixed-species LVL were on average equal to and 7% higher than the predicted values given in Eurocode 5.

Nailplated timber trusses are widely used in residential housing. However, there is limited evidence of use or research on the application of nailplated trusses in exposed environments. It is common knowledge to the nailplated truss industry that weather-exposed trusses experience a phenomenon referred to as “nailplate backout”, where the nailplates separate from the timber surface due to the shrink-swell mechanism of the timber in response to its varying moisture content. This paper investigates the performance of innovative nailplated joints on: (1) stopping moisture-driven backout and (2) increasing the capacity of the joints, when compared to currently used joints, after exposure to severe moisture cycling. Three different experimental sets of joints were manufactured to achieve these outcomes, with Set 1 and Set 2 containing 100 splice and 100 butt joints while Set 3 had 40 splice and 40 butt joints. Sets 1 and 2 have a re-designed tooth profile where: (1) Set 1 combined a polyurethane adhesive with a modified nailplate tooth designed to allow the adhesive to penetrate the timber and (2) Set 2 implemented a hook in the middle of the nailplate teeth to grab the timber when the nailplate tries to separate from the timber, either from moisture induced backout or from loading. Polyurethane adhesive was also used in Set 3 but on an un-modified tooth profile. To evaluate the efficiency of the new nailplates, control joints with unmodified nailplates were manufactured for each set and tested. All joints were subjected to severe accelerated moisture cycles inside an air-driven kiln with the temperature being kept constant 70 °C and the relative humidity varied between 15 and 95%. The cycles consisted of a 7-h wetting and an 18-h drying period. For Sets 1 and 2, the tensile capacity of the joints was measured after 0, 3, 6, 9 and 12 moisture cycles, while for Set 3, it was only measured after 0 and 12 cycles. The backout was recorded after each moisture cycle for Sets 1 and 2 and after 12 cycles for Set 3. The average backout of Set 1 and Set 2 control joints after 12 severe cycles was 1.13 mm and 1.01 mm, respectively, while the addition of glue and a hook reduced the backout to 0.56 and 0.92 mm, respectively. In terms of capacity, the adhesive in Set 1 increased the capacity for the splice joints and butt joints by 43% and 13%, respectively. In Set 2, the hook only marginally increased the capacity of the splice joints by 13% and reduced the average butt joint capacity. Observations were made regarding the failure modes of the joints. The addition of the adhesive and hook to the nailplate teeth resulted in more joints failing due to the capacity of the timber rather than due to the nailplate separating from the timber during the tensile testing.

International audience; Iron oxide nanoparticles were synthesized by an original multistep seed-mediated growth approach. The thermal decomposition of an iron stearate precursor was performed successively up to 5 times to produce nanoparticles with a narrow size distribution from 6.4 to 15.0 nm. The chemical composition and crystal structure of each set of nanoparticles was characterized by TEM, FT-IR, XRD, and Mössbauer spectrometry. Each layer was successively grown at the surface of a pristine Fe3-δO4 nanoparticle by epitaxial relationship and resulted in a single crystal structure. An intermediate wash after each thermal decomposition step resulted in the surface oxidation of each layer. Therefore, the maghemite phase increased relative to the magnetite phase as the nanoparticle expanded. Finally, the study of the magnetic properties by SQUID magnetometry showed the trend of the magnetic anisotropy energy to increase as a function of the nanoparticle size. In contrast, the coercive field and the magnetization saturation display nonmonotonic variations that may result from the interplay of intrinsic and collective properties.

Dense systems of magnetic nanoparticles may exhibit dipolar collective behavior. However, two fundamental questions remain unsolved: i) whether the transition temperature may be affected by the particle anisotropy or it is essentially determined by the intensity of the interparticle dipolar interactions, and ii) what is the minimum ratio of dipole–dipole interaction (Edd) to nanoparticle anisotropy (KefV, anisotropy⋅volume) energies necessary to crossover from individual to collective behavior. A series of particle assemblies with similarly intense dipolar interactions but widely varying anisotropy is studied. The Kef is tuned through different degrees of cobalt-doping in maghemite nanoparticles, resulting in a variation of nearly an order of magnitude. All the bare particle compacts display collective behavior, except the one made with the highest anisotropy particles, which presents “marginal” features. Thus, a threshold of KefV/Edd ≈ 130 to suppress collective behavior is derived, in good agreement with Monte Carlo simulations. This translates into a crossover value of ≈1.7 for the easily accessible parameter TMAX(interacting)/TMAX(non-interacting) (ratio of the peak temperatures of the zero-field-cooled magnetization curves of interacting and dilute particle systems), which is successfully tested against the literature to predict the individual-like/collective behavior of any given interacting particle assembly comprising relatively uniform particles., The authors acknowledge financial support from grant No. MAT2015-65295-R funded by MCIN/AEI/10.13039/501100011033 and by “ERDF A way of making Europe”, grant No. PID2019-106229RB-I00 funded by MCIN/AEI/10.13039/501100011033 and the Spanish MEC (through the contract No. BEAGAL18/00095). The authors also acknowledge funding from UCLM's Plan Propio, the Swedish Research Council (VR), the Universidad Pública de Navarra (grant No. PJUPNA2020) and the Generalitat de Catalunya (grant No. 2017-SGR-292). ICN2 is funded by the CERCA program/Generalitat de Catalunya and supported by SEV-2017-0706 grant funded by MCIN/AEI/10.13039/501100011033. K.T., D.P., and M.V. acknowledge support from the European Union's Horizon 2020 Programme: under gran agreement No. 731976 (MAGENTA) and partially the Horizon Europe EIC Pathfinder Programme: under grant agreement No. 101046909 (REMAP).

International audience; Thanks to important advances in synthesis techniques, a wide collection of bimagnetic core-shell nanoparticles with tunable properties was reported in the literature. Such nanoparticles may combine two phases with different intrinsic magnetic properties (magnetization, anisotropy, coercive field, etc.). Core-shell structures with large interfaces usually favor efficient exchange coupling between both phases that may result in the enhancement of the effective magnetic anisotropy energy and of the coercive field. In this context, the chemical composition and the crystal structure of the core/shell interface in nanoparticles are crucial parameters to modulate efficiently their magnetic properties. Here, we report on the solvent mediated thermal annealing of Fe 3Àd O 4 @CoO nanoparticles in a high boiling point solvent. The structure of nanoparticles was investigated before and after thermal annealing by advanced characterization techniques such as high resolution transmission electron microscopy (HR-TEM), X-ray absorption spectroscopy (XAS), X-ray magnetic circular dichroism (XMCD) and diffraction anomalous near edge structure (DANES). The combination of DANES and XAS/XMCD allowed studying the cationic distribution in spinel and wu ¨stite crystal structures as a function of site occupancy and oxidation state. To the best of our knowledge, it is the first time that DANES is performed to quantitatively investigate the chemical composition of biphasic metal oxide nanoparticles. Hence, we have investigated precisely the chemical composition of the spinel phase and that of the wu ¨stite phase. Besides the partial solubilisation of the CoO shell observed by HR-TEM, thermal annealing favors the formation of a thicker intermediate Co-doped ferrite layer at the spinel/wu ¨stite interface. Such significant modifications of the core@shell structure markedly influence interfacial coupling phenomena between the core and the shell, hence offering wide perspectives towards nanoparticles with tunable magnetic properties for a variety of applications.

Nanoparticles that combine several magnetic phases offer wide perspectives for cutting edge applications because of the high modularity of their magnetic properties. Besides the addition of the magnetic characteristics intrinsic to each phase, the interface that results from core–shell and, further, from onion structures leads to synergistic properties such as magnetic exchange coupling. Such a phenomenon is of high interest to overcome the superparamagnetic limit of iron oxide nanoparticles which hampers potential applications such as data storage or sensors. In this manuscript, we report on the design of nanoparticles with an onion-like structure which has been scarcely reported yet. These nanoparticles consist of a Fe3−δO4 core covered by a first shell of CoFe2O4 and a second shell of Fe3−δO4, e.g., a Fe3−δO4@CoFe2O4@Fe3−δO4 onion-like structure. They were synthesized through a multistep seed-mediated growth approach which consists consists in performing three successive thermal decomposition of metal complexes in a high-boiling-point solvent (about 300 °C). Although TEM micrographs clearly show the growth of each shell from the iron oxide core, core sizes and shell thicknesses markedly differ from what is suggested by the size increasing. We investigated very precisely the structure of nanoparticles in performing high resolution (scanning) TEM imaging and geometrical phase analysis (GPA). The chemical composition and spatial distribution of atoms were studied by electron energy loss spectroscopy (EELS) mapping and spectroscopy. The chemical environment and oxidation state of cations were investigated by 57Fe Mössbauer spectrometry, soft X-ray absorption spectroscopy (XAS) and X-ray magnetic circular dichroism (XMCD). The combination of these techniques allowed us to estimate the increase of Fe2+ content in the iron oxide core of the core@shell structure and the increase of the cobalt ferrite shell thickness in the core@shell@shell one, whereas the iron oxide shell appears to be much thinner than expected. Thus, the modification of the chemical composition as well as the size of the Fe3−δO4 core and the thickness of the cobalt ferrite shell have a high impact on the magnetic properties. Furthermore, the growth of the iron oxide shell also markedly modifies the magnetic properties of the core–shell nanoparticles, thus demonstrating the high potential of onion-like nanoparticles to accurately tune the magnetic properties of nanoparticles according to the desired applications., K.S. was supported by a PhD grant from the French Agence Nationale de la Recherche (ANR) under the reference ANR11-LABX-0058-NIE within the Investissement d’Avenir program ANR-10-IDEX-0002-02 and SOLEIL synchrotron/Laboratoire Léon Brillouin fellowship. The authors are grateful to SOLEIL synchrotron light source for providing the access to DEIMOS beamline and to DIAMOND synchrotron light source for providing access to BLADE beamline. HRSTEM and STEM-EELS studies were conducted at the Laboratorio de Microscopias Avanzadas, Universidad de Zaragoza, Spain. S.H. is grateful to DFG (HE 7675/1-1). R.A. gratefully acknowledges the support from the Spanish Ministry of Economy and Competitiveness (MINECO) and the MICINN through project grants MAT2016-79776-P (AEI/FEDER, UE) and PID2019-104739GB-100/AEI/10.13039/501100011033 as well as from the European Union H2020 program “ESTEEM3” (823717).

Dexterous manipulation of objects heavily relies on the feedback provided by the tactile afferents innervating the fingertips. Previous studies have suggested that humans might take advantage of partial slip, localized loss of grip between the skin and the object, to gauge the stability of a contact and react appropriately when it is compromised, that is, when slippage is about to happen. To test this hypothesis, we asked participants to perform point-to-point movements using a manipulandum. Through optical imaging, the device monitored partial slip at the contact interface, and at the same time, the forces exerted by the fingers. The level of friction of the contact material was changed every five trials. We found that the level of grip force was systematically adjusted to the level of friction, and thus partial slip was limited to an amount similar across friction conditions. We suggest that partial slip is a key signal for dexterous manipulation and that the grip force is regulated to continuously maintain an upper bound on partial slip across friction conditions.

The global climate change imperative presents a particular challenge because of the scale and nature of the investment needed in developing countries, coupled with the difficulty of raising long term debt in many of them. Project finance can help to address this challenge because it enables separation and allocation of different risks to different parties, which can help to attract different funders with different risk appetites. In particular, it is a vehicle to segregate green assets for funding and could assist in incorporating targeted credit enhancement products, such as those offered by the World Bank and other governmental agencies looking to promote clean energy investments. This international dimension is critical, as the challenge will require substantial outside support and innovation. The constraint is not the global availability of finance, but the risk profile of the projects (mostly local-currency generating projects with longer-term infrastructure-type returns) and the availability of the necessary skilled resources. Unless addressed, these constraints will continue to limit the availability of debt finance for clean energy projects in developing countries and thus the ability to achieve global climate change objectives.

B cells and T cells are key players in the defence against infections and malignancies. To exert their function, B cells and T cells differentiate into effector and memory cells. Tight regulation of these differentiation processes is key to prevent their malfunction, which can result in life-threatening disease. Lymphocyte differentiation relies on the appropriate timing and dosage of regulatory molecules, and post-transcriptional gene regulation (PTR) is a key player herein. PTR includes the regulation through RNA-binding proteins (RBPs), which control the fate of RNA and its translation into proteins. To date, a comprehensive overview of the RBP expression throughout lymphocyte differentiation is lacking. Using transcriptome and proteome analyses, we here catalogued the RBP expression for human B cells and T cells. We observed that even though the overall RBP expression is conserved, the relative RBP expression is distinct between B cells and T cells. Differentiation into effector and memory cells alters the RBP expression, resulting into preferential expression of different classes of RBPs. For instance, whereas naive T cells express high levels of translation-regulating RBPs, effector T cells preferentially express RBPs that modulate mRNA stability. Lastly, we found that cytotoxic CD8+ and CD4+ T cells express a common RBP repertoire. Combined, our study reveals a cell type-specific and differentiation-dependent RBP expression landscape in human lymphocytes, which will help unravel the role of RBPs in lymphocyte function.

CD4+ T cells are key contributors in the induction of adaptive immune responses against pathogens. Even though CD4+ T cells are primarily classified as noncytotoxic helper T cells, it has become appreciated that a subset of CD4+ T cells is cytotoxic. However, tools to identify these cytotoxic CD4+ T cells are lacking. We recently showed that CD29 (integrin β1, ITGB1) expression on human CD8+ T cells enriches for the most potent cytotoxic T cells. In this study, we questioned whether CD29 expression also associates with cytotoxic CD4+ T cells. We show that human peripheral blood–derived CD29hiCD4+ T cells display a cytotoxic gene expression profile, which closely resembles that of CD29hi cytotoxic CD8+ T cells. This CD29hi cytotoxic phenotype was observed ex vivo and was maintained in in vitro cultures. CD29 expression enriched for CD4+ T cells, which effectively produced the proinflammatory cytokines IFN-γ, IL-2, and TNF-α, and cytotoxic molecules. Lastly, CD29-expressing CD4+ T cells transduced with a MART1-specific TCR showed target cell killing in vitro. In conclusion, we demonstrate in this study that CD29 can be employed to enrich for cytotoxic human CD4+ T cells.

Rendering tactile effects on a touch screen via electrovibration has many potential applications. However, our knowledge on tactile perception of change in friction and the underlying contact mechanics are both very limited. In this article, we investigate the tactile perception and the contact mechanics for a step change in friction under electrovibration during a relative sliding between a finger and the surface of a capacitive touch screen. First, we conduct magnitude estimation experiments to investigate the role of normal force and sliding velocity on the perceived tactile intensity for a step increase and decrease in friction, called rising friction (RF) and falling friction (FF). To investigate the contact mechanics involved in RF and FF, we then measure the frictional force, the apparent contact area, and the strains acting on the fingerpad during sliding at a constant velocity under three different normal loads using a custom-made experimental set-up. The results show that the participants perceived RF stronger than FF, and both the normal force and sliding velocity significantly influenced their perception. These results are supported by our mechanical measurements; the relative change in friction, the apparent contact area, and the strain in the sliding direction were all higher for RF than those for FF, especially for low normal forces. Taken together, our results suggest that different contact mechanics take place during RF and FF due to the viscoelastic behavior of fingerpad skin, and those differences influence our tactile perception of a step change in friction., Scientific and Technological Research Council of Turkey (TÜBİTAK)

Humans can quickly adjust their grip force to a change in friction at the object-skin interface during dexterous manipulation in a precision grip. To perform this adjustment, they rely on the feedback of the mechanoreceptive afferents innervating the fingertip skin. Because these tactile afferents encode information related to skin deformation, the nature of the feedback signaling a change in friction must somehow originate from a difference in the way the skin deforms when manipulating objects of different frictions. To better characterize the origin of the underlying sensory events, we asked human participants to perform a grip-lifting task with a manipulandum equipped with an optical imaging system. This system enabled to monitor fingertip skin strains through transparent plates of glass that had different levels of friction. We observed that, following an unexpected change in friction, participants adapted their grip force within 370ms after contact with the surface. By comparing the deformation patterns when unexpectedly switching from a high to a low friction condition, we found a significant increase in skin deformation inside the contact area arising over 100ms before the motor response, during the loading phase, suggesting that local and partial deformation patterns prior to lift-off are used in the nervous system to adjust the grip force as a function of the frictional condition.

Nanoparticle assemblies are very attractive because they allow the fine-tuning of magnetic properties by taking advantage of collective behavior ruled by interparticle interactions. Nevertheless, great efforts to control the spatial arrangement of nanoparticles still have to be developed in order to integrate such nanomaterials in devices for applications in fields such as sensors and recording media. Herein, we report on the assembly of iron oxide magnetic nanoparticles promoted by copper-catalyzed alkyne-azide cycloaddition (CuAAC) “click” reaction. Azido-terminated nanoparticles were assembled onto alkyne-terminated gold substrates. The assembly mechanism was investigated by monitoring the density of nanoparticles as a function of their size and concentration. The kinetics of the assembly process is exponential and is favored by the increase of the nanoparticle size and of the concentration. We show that the assembly of nanoparticles is controlled by the random sequential adsorption (RSA) mechanism below a critical size. In contrast, large nanoparticles allow strong dipolar interactions which participate actively in the assembly process, thus they avoid the RSA pathway. These two different mechanism pathways have a significant influence on the spatial arrangement of nanoparticles. The RSA results in rather isolated small nanoparticles at the earliest reaction times which become gradually a discontinuous monolayer. In contrast, the dipolar interaction assisted RSA mechanism (DIA-RSA) favors linear or 2D small assemblies which quickly grow in tight-packed monolayers of nanoparticles. Finally, the magnetic collective properties of these assemblies are markedly favored by the increase of the nanoparticle size.

The main objective of this study was to investigate the key mechanical properties of cross-banded laminated veneer lumbers (LVL-C) manufactured from blending veneers recovered from sub-optimal native forest spotted gum and plantation hoop pine logs. The recovered veneers were separated into three grades based on their dynamic modulus of elasticity (MOE). Additionally, the spotted gum veneers were visually graded to evaluate whether a relationship exists between the MOE-based and visual grades. In total, six 12-ply reference LVL and six mixed-species 12-ply LVL-C panels were manufactured and analyzed for (i) flatwise and edgewise bending performance; (ii) bearing and tension strength perpendicular to the grain; and (iii) longitudinal-tangential shear strength. Little correlation was found between MOE-based and visual grades for the spotted gum veneers. The LVL- C showed flatwise and edgewise MOE up to 24% and 13% lower, respectively, than the reference mixed-species LVL. The flatwise and edgewise modulus of rupture were up to 39% and 19% lower, respectively. On average, the tensile and bearing strengths of the LVL-C were considerably higher than the hoop pine LVL and mixed-species LVL, with the former being approximately three times higher. The manufactured LVL-C showed markedly higher bending properties and tensile strengths than commercial LVL-C products.

Rotary veneers from spotted gum (Corymbia citriodora) and white cypress pine logs (Callitris glaucophylla) recovered from the native forest in Queensland, as well as Queensland plantation hoop pine (Araucaria cunninghamii) logs were used to manufacture LVL products following six different lay-up strategies including blended species LVL. The different lay-up strategies were to determine the opportunities for improving the mechanical performance of plantation softwood LVL by including native forest veneers. The manufactured products were evaluated for their bending performance, tension, bearing strength perpendicular to the grain, and longitudinal-tangential shear strength. The all-spotted gum LVL showed superior performance in all testing compared to other construction strategies. Blending even a small amount of spotted gum veneer with plantation hoop pine veneer resulted in improved mechanical performance, especially in flatwise bending. Opportunities exist to develop more optimised construction strategies that target specific product performances while optimising the use of the variable veneer qualities generated from log processing.

This paper presents a methodology to optimise the manufacturing strategy of structural cross-banded laminated veneer lumbers (LVL-C) manufactured by mixing species. The methodology is illustrated by blending native-forest spotted gum (Corymbia citriodora) with plantation southern pine (Caribbean pine (Pinus caribaea var. hondurensis) and slash pine (Pinus elliottii var. elliottii)) veneers. The aim is to minimise the cost of a family of products (i.e. several types of product manufactured from the same veneered stock) using a maximum allowable number of hardwood veneers, and in which each product has different targeted stiffness and embedment strength. Genetic algorithm, which is widely used in the optimisation of structural products, was selected as the optimisation algorithm. The orientation of the veneers and veneer grades are considered as design variables. Results show that the developed algorithm was able to consistently converge to similar solutions for all investigated cases, demonstrating its robustness. For all cases, the “high” modulus of elasticity graded spotted gum and southern pine veneers were found to be predominant in the final products. LVL-C are found in cases with high targeted embedment strength. Finally, the obtained optimum construction strategies are validated against experimental results.

This paper presents the reliability analysis of Laminated Veneer Lumber (LVL) beams manufactured from veneers recovered from early to mid-rotation (juvenile) subtropical hardwood plantation logs, with plantations established either for sawn timber applications or pulpwood production. While these logs have a high number of natural defects (knots, gum veins, grain deviation, etc.), are considered of low quality and have little to no commercial value, they produce high strength Veneered Based Composite products, such as Plywood and LVL. Yet, the reliability of these products is unknown. In this paper, the relationship between the reliability index and the capacity factors, also referred to as “resistance factors”, used in design equations of such LVL beams in both edge and flat bending is investigated taking into account the load duration effects (damage accumulation). The relationship is presented for six different beam sizes, four grades and three hardwood species (Gympie messmate (Eucalyptus cloeziana), spotted gum (Corymbia citriodora) and southern blue gum (Eucalyptus globulus)) using the strength distribution of the beams recently quantified by the authors. Parametric studies on five main design load combinations stipulated in the Australian standard and three rates of damage accumulation, based on the data available in the literature, are conducted. Results show that the reliability index is highly sensitive to the damage accumulation rate and that the “Dead + Sustained and Extraordinary live loads” and “Dead + Wind + Sustained live loads” load combinations govern the choice of the capacity factor. Recommendations are made on the appropriate capacity factors to be used for various service categories of structures. The proposed capacity factors are found to be 5%–12% lower than the ones currently used in Australia for the LVL beams manufactured from mature softwood logs, as opposed to juvenile hardwood logs as in the proposed products.

Accurately determining the transverse shear stiffness of steel storage rack upright frames is essential in calculating the elastic buckling load, performing earthquake design and serviceability checks. International racking design specifications recommend different approaches to evaluate this stiffness. The Rack Manufacturers Institute (RMI) specification conservatively uses an analytical solution based on Timoshenko and Gere's theory while the European (EN15512) and Australian (AS4084) specifications recommend experimental testing to be conducted. Previous studies have shown that Finite Element Analyses (FEA), solely using beam elements, fail to reproduce experimental test results and may overestimate the transverse shear stiffness by a factor up to 25. This discrepancy is likely attributed to the local deformations occurring at the bolted joints. In this paper, a model to capture the transverse shear stiffness of upright frames is developed using shell elements and advanced FEA. Its accuracy is verified against published experimental test results performed on three commercially used upright frame configurations with lip-to-lip bracing pattern. The model accurately reproduces the experimental stiffness, with differences ranging from 2% to 17%. Based on the FE model, the factors contributing to the transverse shear deformation of the frames are quantified and discussed for both lip-to-lip and back-to-back bracing patterns. For lip-to-lip upright frames, results show that the local deformations at the end of bracing members contributes the most to the shear deformation of the frames. For back-to-back upright frames, bolt bending and axial deformation of braces contribute the most to the shear deformation of the frames. Results from this paper would assist the racking industry in improving their products by focusing on the factors influencing the most the behaviour of the frames.

Reinforced concrete (RC) flat plate structures are broadly used in car parks, residential and office buildings due to their economic and architectural advantages. However, this structural system is inherently prone to punching shear failure, which may propagate horizontally and vertically, ultimately leading to the progressive collapse of the entire structure or of a large portion of it. This paper presents the experimental results from two quasi-static large-displacement tests performed on a 1/3 scale, 2 × 2-bay, RC flat plate substructure subjected to corner column removal scenarios. The specimen was tested twice with different corner reinforcement configurations: (i) firstly, one corner column, with torsional strips, was removed and the Uniformly Distributed Load (UDL) on the bay adjacent to the removed column was increased to failure (Test T1), and (ii) secondly, as the damage was concentrated in the vicinity of removed corner column in (i), the corner column diagonally opposite to the first removed one, without torsional strips, was removed. The UDL on the bay adjacent to the second removed column was also increased to failure (Test T2). Different failure and post-failure behaviours, failure modes, and collapse resisting mechanisms between the two tests were witnessed, presented and analysed. Results show that 80% to 110% of the applied load is transferred to the two edge columns adjacent to the removed corner column throughout the entire two tests. The ultimate load carrying capacity for T1 is found to be 1.7 times smaller than the one for T2.

A number of international timbers of high commercial importance are extremely difficult to glue, which is significantly hindering access to global market opportunities for engineered wood products, especially for heavily demanded structural products. Some particularly problematic timbers in Australia are the dominant commercial hardwood species, including spotted gum (Corymbia spp.) and Darwin stringybark (Eucalyptus tetrodonta). These species are renowned for their very high mechanical properties, natural durability and attractive aesthetic appeal. However, they are notoriously difficult to glue, especially for sawn laminate-based engineered wood products, such as structural glue-laminated beams. Despite considerable effort and testing of diverse internationally established best-practice approaches to improve adhesion, glue-laminated beam samples of these timbers still frequently fail to meet the requirements of the relevant standard, mainly due to excessive glue line delamination. This paper discusses the key barriers to effective adhesion of these high-density timbers and particularly emphasises the necessity of achieving greater adhesive penetration. Greater adhesive penetration is required to enhance mechanical interlocking, entanglement and molecular interactions between the adhesive and the wood to achieve stronger and more durable bonds. Potential solutions to enhance adhesive penetration, as well as to improve gluability in general, are discussed in terms of their likelihood to satisfactorily prevent delamination and the potential to be applied at an industrial scale. This new fundamental understanding will assist the development of solutions, allowing industry to commercialise newly engineered wood products made from high-density timbers.

B cells and T cells are key players in the defence against infections and malignancies. To exert their function, B cells and T cells differentiate into effector and memory cells. Tight regulation of these differentiation processes is key to prevent their malfunction, which can result in life-threatening disease. Lymphocyte differentiation relies on the appropriate timing and dosage of regulatory molecules, and post-transcriptional gene regulation (PTR) is a key player herein. PTR includes the regulation through RNA-binding proteins (RBPs), which control the fate of RNA and its translation into proteins. To date, a comprehensive RBP expression map throughout lymphocyte differentiation is lacking. Using transcriptome and proteome analyses, we here provide an RBP expression map for human B cells and T cells. We observed that even though the overall RBP expression is conserved, the relative RBP expression is distinct between B cells and T cells. Differentiation into effector and memory cells alters the RBP expression, resulting into preferential expression of different classes of RBPs. For instance, whereas naïve T cells express high levels of translation-regulating RBPs, effector T cells preferentially express RBPs that modulate mRNA stability. Lastly, we found that cytotoxic CD8+and CD4+T cells express a common RBP repertoire. Combined, our study reveals a cell type-specific and differentiation-dependent RBP expression landscape in human lymphocytes, which will help unravel the role of RBPs in lymphocyte function.

Forests provide important ecosystem services but are being affected by climate change, not only changes in temperature and precipitation but potentially also directly through the plant-physiological effects of increases in atmospheric CO2. We applied a tree-species-based dynamic model (LPJ-GUESS) at a high 5-km spatial resolution to project climate and CO2 impacts on tree species and thus forests in Great Britain. Climatic inputs consisted of a novel large climate scenario ensemble derived from a regional climate model (RCM) under an RCP 8.5 emission scenario. The climate change impacts were assessed using leaf area index (LAI) and net primary productivity (NPP) for the 2030s and the 2080s compared to baseline (1975–2004). The potential CO2 effects, which are highly uncertain, were examined using a constant CO2 level scenario for comparison. Also, a climate vulnerability index was developed to assess the potential drought impact on modeled tree species. In spite of substantial future reductions in rainfall, the mean projected LAI and NPP generally showed an increase over Britain, with a larger increment in Scotland, northwest England, and west Wales. The CO2 increase led to higher projected LAI and NPP, especially in northern Britain, but with little effect on overall geographical patterns. However, without accounting for plant-physiological effects of elevated CO2, NPP in Southern and Central Britain and easternmost parts of Wales showed a decrease relative to 2011, implying less ecosystem service provisioning, e.g., in terms of timber yields and carbon storage. The projected change of LAI and NPP varied from 5 to 100% of the mean change, due to the uncertainty arising from natural weather-induced variability, with Southeast England being most sensitive to this. It was also the most susceptible to climate change and drought, with reduced suitability for broad-leaved trees such as beech, small-leaved lime, and hornbeam. These could lead to important changes in woodland composition across Great Britain.

Nanoparticles that combine several magnetic phases offer wide perspectives for cutting edge applications because of the high modularity of their magnetic properties. Besides the addition of the magnetic characteristics intrinsic to each phase, the interface that results from core-shell and, further, from onion structures leads to synergistic properties such as magnetic exchange coupling. Such a phenomenon is of high interest to overcome the superparamagnetic limit of iron oxide nanoparticles which hampers potential applications such as data storage or sensors. In this manuscript, we report on the design of nanoparticles with an onion-like structure which has been scarcely reported yet. These nanoparticles consist of a Fe

Each day, about 1012 erythrocytes and platelets are released into the bloodstream. This substantial output from hematopoietic stem cells is tightly regulated by transcriptional and epigenetic factors. Whether and how circular RNAs (circRNAs) contribute to the differentiation and/or identity of hematopoietic cells is to date not known. We recently reported that erythrocytes and platelets contain the highest levels and numbers of circRNAs among hematopoietic cells. Here, we provide the first detailed analysis of circRNA expression during erythroid and megakaryoid differentiation. CircRNA expression not only significantly increased upon enucleation, but also had limited overlap between progenitor cells and mature cells, suggesting that circRNA expression stems from regulated processes rather than resulting from mere accumulation. To study circRNA function in hematopoiesis, we first compared the expression levels of circRNAs with the translation efficiency of their mRNA counterpart. We found that only one out of 2531 (0.04%) circRNAs associated with mRNA-translation regulation. Furthermore, irrespective of thousands of identified putative open reading frames, deep ribosome-footprinting sequencing, and mass spectrometry analysis provided little evidence for translation of endogenously expressed circRNAs. In conclusion, circRNAs alter their expression profile during terminal hematopoietic differentiation, yet their contribution to regulate cellular processes remains enigmatic.

CD4+ T cell are key contributors in the induction of adaptive immune responses against pathogens. Even though CD4+ T cells are primarily classified as non-cytotoxic helper T cells, it has become appreciated that a subset of CD4+ T cells is cytotoxic. However, tools to identify these cytotoxic CD4+ T cells are lacking. We recently showed that CD29 (Integrin Beta 1, ITGB1) expression on human CD8+ T cells enriches for the most potent cytotoxic T cells. Here, we questioned whether CD29 expression also associates with cytotoxic CD4+ T cells. We show that human peripheral blood-derived CD29hiCD4+ T cells display a cytotoxic gene expression profile, which closely resembles that of CD29hi cytotoxic CD8+ T cells. This CD29hi cytotoxic phenotype was observed ex vivo and was maintained in in vitro cultures. CD29 expression enriched for CD4+ T cells, which effectively produced the pro-inflammatory cytokines IFN-γ, IL-2, and TNF-α, and cytotoxic molecules. Lastly, CD29-expressing CD4+ T cells transduced with a MART-1 specific TCR showed target cell killing in vitro. In conclusion, we here demonstrate that CD29 can be employed to enrich for cytotoxic human CD4+ T cells.

International audience; Iron carboxylates are widely used as iron precursors in the thermal decomposition process or considered as in situ formed intermediate precursors. Their molecular and three-dimensional (3D)-structural nature has been shown to affect the shape, size, and composition of the resulting iron oxide nanoparticles (NPs). Among carboxylate precursors, stearates are particularly attractive because of their higher stability to aging and hydration and they are used as additives in many applications. Despite the huge interest of iron stearates, very few studies aimed up to now at deciphering their full metal-ligand structures and the mechanisms allowing us to achieve in a controlled manner the bottom-up NP formation. In this work, we have thus investigated the molecular structure and composition of two iron stearate precursors, synthesized by introducing either two (FeSt2) or three (FeSt3) stearate (St) chains. Interestingly, both iron stearates consist of lamellar structures with planes of iron polynuclear complexes (polycations) separated with stearate chains in all-trans conformation. The iron content in polycations was found very different between both iron stearates. Their detailed characterizations indicate that FeSt2 is mainly composed of [Fe3-(μ3-O)St6·xH2O]Cl, with no (or few) free stearate, whereas FeSt3 is a mixture of mainly [Fe7(μ3-O(H))6(μ2-OH)xSt12–2x]St with some [Fe3(μ3-O)St6·xH2O]St and free stearic acid. The formation of bigger polynuclear complexes with FeSt3 was related to higher hydrolysis and condensation rates within the iron(III) chloride solution compared to the iron(II) chloride solution. These data suggested a nucleation mechanism based on the condensation of polycation radicals generated by the catalytic departure of two stearate chains from an iron polycation-based molecule.