Transgressive and parental dominant gene expression and cytosine methylation during seed development in Brassica napus hybrids.

KEY MESSAGE: Transcriptomic and epigenomic profiling of gene expression and small RNAs during seed and seedling development reveals expression and methylation dominance levels with implications on early stage heterosis in oilseed rape. The enhanced performance of hybrids through heterosis remains a key aspect in plant breeding; however, the underlying mechanisms are still not fully elucidated. To investigate the potential role of transcriptomic and epigenomic patterns in early expression of hybrid vigor, we investigated gene expression, small RNA abundance and genome-wide methylation in hybrids from two distant Brassica napus ecotypes during seed and seedling developmental stages using next-generation sequencing. A total of 31117, 344, 36229 and 7399 differentially expressed genes, microRNAs, small interfering RNAs and differentially methylated regions were identified, respectively. Approximately 70% of the differentially expressed or methylated features displayed parental dominance levels where the hybrid followed the same patterns as the parents. Via gene ontology enrichment and microRNA-target association analyses during seed development, we found copies of reproductive, developmental and meiotic genes with transgressive and paternal dominance patterns. Interestingly, maternal dominance was more prominent in hypermethylated and downregulated features during seed formation, contrasting to the general maternal gamete demethylation reported during gametogenesis in angiosperms. Associations between methylation and gene expression allowed identification of putative epialleles with diverse pivotal biological functions during seed formation. Furthermore, most differentially methylated regions, differentially expressed siRNAs and transposable elements were in regions that flanked genes without differential expression. This suggests that differential expression and methylation of epigenomic features may help maintain expression of pivotal genes in a hybrid context. Differential expression and methylation patterns during seed formation in an F1 hybrid provide novel insights into genes and mechanisms with potential roles in early heterosis.

Viscoelasticity of non-colloidal hydrogel particle suspensions at the liquid-solid transition.

Suspensions of soft particles transition from a viscous fluid to a soft material upon increases in phase volume. The criteria defining the transition to this jammed state are difficult to define due to the porous and deformable nature of soft particles. Here, we characterise the rheology of aqueous suspensions of industrially relevant non-colloidal, polydisperse, frictional agarose microgels and evaluate shear and viscoelastic behaviour across a range of phase volumes from the dilute regime to the highly concentrated regime. In order to model the viscoelastic response of suspensions without free fitting parameters, the random close packing volume fraction (φrcp) and the particle modulus are determined, respectively, from particle size distribution measurements and direct measurements of reduced elastic modulus of individual particles (Erp) using Atomic Force Microscopy. It is found that at φrcp, previously shown to correspond to divergence of the viscosity, also corresponds to the suspension transition from a viscous to viscoelastic fluid. However, the transition to a jammed solid-like state (φj) occurs at phase volumes exceeding this value (i.e. φj > φrcp). The suspension modulus and its sudden growth at φj are well-predicted by the Evans and Lips model that incorporates the Erp of the hydrogel particles. This rheological behaviour showing a dual transition is reminiscent of two families of systems: (i) colloidal suspensions and (ii) frictional-adhesive non-colloidal suspensions. However, it does not strictly follow either case. We propose that the width of the transition region is dictated by frictional contact, particle size distribution and particle modulus, and plan to further probe this in future work.

Mapping nano-scale mechanical heterogeneity of primary plant cell walls.

Nanoindentation experiments are performed using an atomic force microscope (AFM) to quantify the spatial distribution of mechanical properties of plant cell walls at nanometre length scales. At any specific location on the cell wall, a complex (non-linear) force-indentation response occurs that can be deconvoluted using a unique multiregime analysis (MRA). This allows an unambiguous evaluation of the local transverse elastic modulus of the wall. Nanomechanical measurements on suspension-cultured cells (SCCs), derived from Italian ryegrass (Lolium multiflorum) starchy endosperm, show three characteristic modes of deformation and a spatial distribution of elastic moduli across the surface. 'Soft' and 'hard' domains are found across length scales between 0.1 µm and 3 µm, which is well above a typical pore size of the polysaccharide mesh. The generality and wider applicability of this mechanical heterogeneity is verified through in planta characterization on leaf epidermal cells of Arabidopsis thaliana and L. multiflorum The outcomes of this research provide a basis for uncovering and quantifying the relationships between local wall composition, architecture, cell growth, and/or morphogenesis.

Multicomponent effective medium-correlated random walk theory for the diffusion of fluid mixtures through porous media.

Molecular transport in nanoconfined spaces plays a key role in many emerging technologies for gas separation and storage, as well as in nanofluidics. The infiltration of fluid mixtures into the voids of porous frameworks having complex topologies is common place to these technologies, and optimizing their performance entails developing a deeper understanding of how the flow of these mixtures is affected by the morphology of the pore space, particularly its pore size distribution and pore connectivity. Although several techniques have been developed for the estimation of the effective diffusivity characterizing the transport of single fluids through porous materials, this is not the case for fluid mixtures, where the only alternatives rely on a time-consuming solution of the pore network equations or adaptations of the single fluid theories which are useful for a limited type of systems. In this paper, a hybrid multicomponent effective medium-correlated random walk theory for the calculation of the effective transport coefficients matrix of fluid mixtures diffusing through porous materials is developed. The theory is suitable for those systems in which component fluxes at the single pore level can be related to the potential gradients of the different species through linear flux laws and corresponds to a generalization of the classical single fluid effective medium theory for the analysis of random resistor networks. Comparison with simulation of the diffusion of binary CO(2)/H(2)S and ternary CO(2)/H(2)S/C(3)H(8) gas mixtures in membranes modeled as large networks of randomly oriented pores with both continuous and discrete pore size distributions demonstrates the power of the theory, which was tested using the well-known generalized Maxwell-Stefan model for surface diffusion at the single pore level.

On the interfacial lithium dynamics in Li7La3Zr2O12:poly(ethylene oxide) (LiTFSI) composite polymer-ceramic solid electrolytes under strong polymer phase confinement.

A better molecular-level understanding of Li+ diffusion through ceramic/polymer interfaces is key to design high-performance composite solid-state electrolytes for all-solid-state batteries. By considering as a case study a composite electrolyte constituted by Li+ conductive Ga3+ doped-Li7La3Zr2O12 (LLZO) garnet fillers embedded within a poly(ethylene oxide) and lithium bis(trifluoromethanesulfonyl) imide polymer matrix (PEO(LiTFSI)), we investigate Li+ interfacial dynamics at conditions of high polymer confinement, with large filler particles in a fully amorphous polymer phase. Such confinement scenario is aimed to capture the conditions near the percolation threshold, at which conductivity enhancement is often reported. Using molecular dynamics simulations combined with the generalized shadow hybrid Monte Carlo method and umbrella sampling calculations, we explain why the hopping towards the polymer phase of the Li+ sitting on the LLZO surface is thermodynamically hindered, while hopping of Li+ from the polymer to the LLZO is kinetically slowed-down by rigidified polymer near the interface. In addition, we demonstrate how the overlap of LLZO-bound polymer chains at high confinement leads to a decrease of Li+ diffusivity within the interstitial space. We put forward that these insights are relevant to interpret the variation of ionic conductivity as a function of volume fraction and filler particle sizes also below the glass transition temperature of the polymer, at the typical operating conditions of lithium ion batteries.

Impact of Glucose on the Nanostructure and Mechanical Properties of Calcium-Alginate Hydrogels.

Alginate is a polysaccharide obtained from brown seaweed that is widely used in food, pharmaceutical, and biotechnological applications due to its versatility as a viscosifier and gelling agent. Here, we investigated the influence of the addition of glucose on the structure and mechanical properties of alginate solutions and calcium-alginate hydrogels produced by internal gelation through crosslinking with Ca2+. Using 1H low-field nuclear magnetic resonance (NMR) and small angle neutron scattering (SANS), we showed that alginate solutions at 1 wt % present structural heterogeneities at local scale whose size increases with glucose concentration (15-45 wt %). Remarkably, the molecular conformation of alginate in the gels obtained from internal gelation by Ca2+ crosslinking is similar to that found in solution. The mechanical properties of the gels evidence an increase in gel strength and elasticity upon the addition of glucose. The fitting of mechanical properties to a poroelastic model shows that structural changes within solutions prior to gelation and the increase in solvent viscosity contribute to the gel strength. The nanostructure of the gels (at local scale, i.e., up to few hundreds of Å) remains unaltered by the presence of glucose up to 30 wt %. At 45 wt %, the permeability obtained by the poroelastic model decreases, and the Young's modulus increases. We suggest that macro (rather than micro) structural changes lead to this behavior due to the creation of a network of denser zones of chains at 45 wt % glucose. Our study paves the way for the design of calcium-alginate hydrogels with controlled structure for food and pharmaceutical applications in which interactions with glucose are of relevance.

Frequent spontaneous structural rearrangements promote rapid genome diversification in a Brassica napus F1 generation.

In a cross between two homozygous Brassica napus plants of synthetic and natural origin, we demonstrate that novel structural genome variants from the synthetic parent cause immediate genome diversification among F1 offspring. Long read sequencing in twelve F1 sister plants revealed five large-scale structural rearrangements where both parents carried different homozygous alleles but the heterozygous F1 genomes were not identical heterozygotes as expected. Such spontaneous rearrangements were part of homoeologous exchanges or segmental deletions and were identified in different, individual F1 plants. The variants caused deletions, gene copy-number variations, diverging methylation patterns and other structural changes in large numbers of genes and may have been causal for unexpected phenotypic variation between individual F1 sister plants, for example strong divergence of plant height and leaf area. This example supports the hypothesis that spontaneous de novo structural rearrangements after de novo polyploidization can rapidly overcome intense allopolyploidization bottlenecks to re-expand crops genetic diversity for ecogeographical expansion and human selection. The findings imply that natural genome restructuring in allopolyploid plants from interspecific hybridization, a common approach in plant breeding, can have a considerably more drastic impact on genetic diversity in agricultural ecosystems than extremely precise, biotechnological genome modifications.

Molecular transport in nanopores: a theoretical perspective.

Molecular transport in nanopores plays a central role in many emerging nanotechnologies for gas separation and storage, as well as in nanofluidics. Theories of the transport provide an understanding of the mechanisms that influence the transport and their interplay, and can lead to tractable models that can be used to advance these nanotechnologies through process analysis and optimisation. We review some of the most influential theories of fluid transport in small pores and confined spaces. Starting from the century old Knudsen formulation, the dusty gas model and several other related approaches that share a common point of departure in the Maxwell-Stefan diffusion equations are discussed. In particular, the conceptual basis of the models and the validity of the assumptions and simplifications necessary to obtain their final results are analysed. It is shown that the effect of adsorption is frequently either neglected, or treated on an ad hoc basis, such as through the division of the pore flux into gas-phase and surface diffusion contributions. Furthermore, while it is commonplace to assume that cross-sectional pressure is uniform, it is demonstrated that this violates the Gibbs-Duhem relation and that it is the chemical potential that essentially remains constant in the cross-section, as near-equilibrium density profiles are preserved even during transport. The Dusty Gas model and Maxwell-Stefan model for surface diffusion are analysed, and their strengths and weaknesses discussed, illustrating the use of conflicting choices of frames of reference in the former case, and the importance of assigning appropriate values for the binary diffusivity in the latter case. The oscillator model, developed in this laboratory, which is exact in the low density limit under diffuse reflection conditions, is shown to represent an advance on the classical Knudsen formula, although the latter frequently appears as a fundamental part of many transport models. The distributed friction model, also developed in this laboratory for the study of multi-component transport at any Knudsen number is discussed and compared with previous approaches. Finally, the outlook for theory and future research needs are discussed.

Unveiling Interfacial Li-Ion Dynamics in Li7La3Zr2O12/PEO(LiTFSI) Composite Polymer-Ceramic Solid Electrolytes for All-Solid-State Lithium Batteries.

Unlocking the full potential of solid-state electrolytes (SSEs) is key to enabling safer and more-energy dense technologies than today's Li-ion batteries. In particular, composite materials comprising a conductive, flexible polymer matrix embedding ceramic filler particles are emerging as a good strategy to provide the combination of conductivity and mechanical and chemical stability demanded from SSEs. However, the electrochemical activity of these materials strongly depends on their polymer/ceramic interfacial Li-ion dynamics at the molecular scale, whose fundamental understanding remains elusive. While this interface has been explored for nonconductive ceramic fillers, atomistic modeling of interfaces involving a potentially more promising conductive ceramic filler is still lacking. We address this shortfall by employing molecular dynamics and enhanced Monte Carlo techniques to gain unprecedented insights into the interfacial Li-ion dynamics in a composite polymer-ceramic electrolyte, which integrates polyethylene oxide plus LiN(CF3SO2)2 lithium imide salt (LiTFSI), and Li-ion conductive cubic Li7La3Zr2O12 (LLZO) inclusions. Our simulations automatically produce the interfacial Li-ion distribution assumed in space-charge models and, for the first time, a long-range impact of the garnet surface on the Li-ion diffusivity is unveiled. Based on our calculations and experimental measurements of tensile strength and ionic conductivity, we are able to explain a previously reported drop in conductivity at a critical filler fraction well below the theoretical percolation threshold. Our results pave the way for the computational modeling of other conductive filler/polymer combinations and the rational design of composite SSEs.

Transcriptomics reveal high regulatory diversity of drought tolerance strategies in a biennial oil crop.

Spring droughts are expected to become more frequent in Central Europe as a result of climate change. Their coincidence with flowering of biennial crops like winter oilseed rape (Brassica napus) can cause major impact for yield development. However, no data is available on the diversity of genetic regulation of drought tolerance during this stage under realistic conditions. Here, we assessed the phenotypic plasticity of drought response for eight diverse B. napus accessions under field-like conditions and linked their stress response to gene and miRNA expression during early and late stress. We observed highly diverse responses, both on the phenotypic and on the gene expression level. Our data suggest that drought tolerant accessions have more effective molecular protection mechanisms like ROS scavenging, source/sink ratio and regulation of developmental timing, compared to otherwise phenotypically similar accessions. Bna.MAP3K13.C05 expression was found to be protective independently of the tolerance mechanism, indicating cross-talk to nitrogen signaling. Moreover, we identified putative miRNA genes in the B. napus genome which respond to stress and may also be involved in protective mechanisms, representing possible breeding targets.

Atomistic Insight into Ion Transport and Conductivity in Ga/Al-Substituted Li7La3Zr2O12 Solid Electrolytes.

Garnet-structured Li7La3Zr2O12 is a promising solid electrolyte for next-generation solid-state Li batteries. However, sufficiently fast Li-ion mobility required for battery applications only emerges at high temperatures, upon a phase transition to cubic structure. A well-known strategy to stabilize the cubic phase at room temperature relies on aliovalent substitution; in particular, the substitution of Li+ by Al3+ and Ga3+ ions. Yet, despite having the same formal charge, Ga3+ substitution yields higher conductivities (10-3 S/cm) than Al3+ (10-4 S/cm). The reason of such difference in ionic conductivity remains a mystery. Here, we use molecular dynamic simulations and advanced sampling techniques to precisely unveil the atomistic origin of this phenomenon. Our results show that Li+ vacancies generated by Al3+ and Ga3+ substitution remain adjacent to Ga3+ and Al3+ ions, without contributing to the promotion of Li+ mobility. However, while Ga3+ ions tend to allow limited Li+ diffusion within their immediate surroundings, the less repulsive interactions associated with Al3+ ions lead to a complete blockage of neighboring Li+ diffusion paths. This effect is magnified at lower temperatures and explains the higher conductivities observed for Ga-substituted systems. Overall, this study provides a valuable insight into the fundamental ion transport mechanism in the bulk of Ga/Al-substituted Li7La3Zr2O12 and paves the way for rationalizing aliovalent substitution design strategies for enhancing ionic transport in these materials.

Visual Attention Patterns Differ in Gynephilic and Androphilic Men and Women Depending on Age and Gender of Targets.

Visual attention patterns measured with eye-tracking techniques provide indirect clues about sexual response. This study aimed to test the category specificity of sexual responses to stimuli varying in gender and age by evaluating both early and late attention of gynephilic and androphilic men and women. We simultaneously presented sexually preferred and nonpreferred stimuli and measured time to first fixation and total duration of fixation on four areas of interest: entire body, then face, chest, and pelvis. Androphilic women's early attention patterns were nonspecific, whereas gynephilic women and both groups of men showed a category-specific pattern for the entire body. In contrast, all groups showed gender-specific patterns of late attention for all areas of interest. We also found support for age specificity of early and late visual attention in all four groups, with greater attention to adult than child stimuli. This study supports the usefulness of a competing stimulus eye-tracking paradigm as a method to examine gender specificity in gynephilic women and androphilic and gynephilic men, and as a measure of age specificity in gynephilic and androphilic men and women.

Expectation of reward differentially modulates executive inhibition.

BACKGROUND: Inhibitory control, a key modulatory component of cognition guiding strategy and behaviour, can be affected by diverse contingencies. We explore here the effect of expectation of reward over behavioural adjustment in a Stop Signal Task modulated by reward. We hypothesize that cognitive control is modulated by different expectation of the reward. METHODS: Participants were allocated to two groups differing in their degree of knowledge in what to expect from rewards. Expected Specific Reward participants (N = 21) were informed of the different monetary feedbacks they would receive after each successful inhibition. Unexpected Reward participants (N = 24) were only told that they would receive monetary reward after correct inhibitory trials, but not the amounts or differences. RESULTS: Our results confirmed previous observations demonstrating a "kick-start effect" where a high reward feedback at the beginning of the task increases response inhibition. The Expected Specific Reward condition seems also to improve inhibitory control -as measured by the stop signal reaction time (SSRT)-, compared to the Unexpected Reward group. CONCLUSIONS: Knowledge of reward magnitudes seems to play a role in cognitive control irrespective of feedback magnitude. The manipulation of reward expectation appears to trigger different strategies for cognitive control, inducing a bottom-up effect of external cues, or a top-down effect given by the anticipation of incoming rewards. This is an early exploration to unearth possible higher order modulators - expectation and motivation- of cognitive control. This approach aims to gain insight into diverse psychopathological conditions related to impulsivity and altered reward systems such as Attention Deficit Hyperactive Disorder (ADHD), personality disorders, substance abuse, pathological gambling and cognitive aspects of Parkinson Disease.

Probing adhesion between nanoscale cellulose fibres using AFM lateral force spectroscopy: The effect of hemicelluloses on hydrogen bonding.

Inter-fibre adhesion is a key contributing factor to the mechanical response and functionality of cellulose-based biomaterials. 'Dip-and-Drag' lateral force atomic force microscopy technique is used here to evaluate the influence of arabinoxylan and xyloglucan on interactions between nanoscale cellulose fibres within a hydrated network of bacterial cellulose. A cohesive zone model of the detachment event between two nano-fibres is used to interpret the experimental data and evaluate inter-fibre adhesion energy. The presence of xyloglucan or arabinoxylan is found to increase the adhesive energy by a factor of 4.3 and 1.3, respectively, which is consistent with these two hemicellulose polysaccharides having different specificity of hydrogen bonding with cellulose. Importantly, xyloglucan's ability to strengthen adhesion between cellulose nano-fibres supports emergent models of the primary plant cell walls (Park & Cosgrove, 2012b), which suggest that xyloglucan chains confined within cellulose-cellulose junctions play a key role in cell wall's mechanical response.

Mucin gel assembly is controlled by a collective action of non-mucin proteins, disulfide bridges, Ca2+-mediated links, and hydrogen bonding.

Mucus is characterized by multiple levels of assembly at different length scales which result in a unique set of rheological (flow) and mechanical properties. These physical properties determine its biological function as a highly selective barrier for transport of water and nutrients, while blocking penetration of pathogens and foreign particles. Altered integrity of the mucus layer in the small intestine has been associated with a number of gastrointestinal tract pathologies such as Crohn's disease and cystic fibrosis. In this work, we uncover an intricate hierarchy of intestinal mucin (Muc2) assembly and show how complex rheological properties emerge from synergistic interactions between mucin glycoproteins, non-mucin proteins, and Ca2+. Using a novel method of mucus purification, we demonstrate the mechanism of assembly of Muc2 oligomers into viscoelastic microscale domains formed via hydrogen bonding and Ca2+-mediated links, which require the joint presence of Ca2+ ions and non-mucin proteins. These microscale domains aggregate to form a heterogeneous yield stress gel-like fluid, the macroscopic rheological properties of which are virtually identical to that of native intestinal mucus. Through proteomic analysis, we short-list potential protein candidates implicated in mucin assembly, thus paving the way for identifying the molecules responsible for the physiologically critical biophysical properties of mucus.

[Estimation of underreporting of Chikungunya virus infection cases in Girardot, Colombia, from November, 2014, to May, 2015].

INTRODUCTION: Chikungunya virus infection in Colombia became epidemic in 2015. It is estimated that there is underreporting of cases to the public health surveillance system which can induce bias in epidemiological projections for decision making, a serious problem, as it veils the real magnitude and actual epidemiological importance of this disease. OBJECTIVE: To estimate the underreporting of cases of chikungunya infection in the municipality of Girardot, Cundinamarca, from November, 2014, to May, 2015. MATERIALS AND METHODS: We conducted a descriptive and retrospective study using surveys in 132 blocks selected by simple random sampling for community active search and the revision of 100% of the individual records of health services and those from the public health surveillance system for institutional active search. The data were analyzed using EpiInfo, version 7. RESULTS: The attack rate was 64.7%. The estimated underreporting was 36.1% for not attending medical consultation while 24.9% of cases were not reported to the public health surveillance system. The principal cause for not seeking medical consultation among those surveyed (n=392; 43%) was self-medication, followed by the collapse of health services (n=207; 23%). RESULTS: The attack rate was 64.7%. The estimated underreporting was 36.1% for not attending medical consultation while 24.9% of cases were not reported to the public health surveillance system. The principal cause for not seeking medical consultation among those surveyed (n=392; 43%) was self-medication, followed by the collapse of health services (n=207; 23%). CONCLUSION: The overall underreporting since the beginning of the epidemic in Girardot was 87.05%.This research explains 60.9% of this underreporting.

Cellulose-pectin composite hydrogels: Intermolecular interactions and material properties depend on order of assembly.

Plant cell walls have a unique combination of strength and flexibility however, further investigations are required to understand how those properties arise from the assembly of the relevant biopolymers. Recent studies indicate that Ca2+-pectates can act as load-bearing components in cell walls. To investigate this proposed role of pectins, bioinspired wall models were synthesised based on bacterial cellulose containing pectin-calcium gels by varying the order of assembly of cellulose/pectin networks, pectin degree of methylesterification and calcium concentration. Hydrogels in which pectin-calcium assembly occurred prior to cellulose synthesis showed evidence for direct cellulose/pectin interactions from small-angle scattering (SAXS and SANS), had the densest networks and the lowest normal stress. The strength of the pectin-calcium gel affected cellulose structure, crystallinity and material properties. The results highlight the importance of the order of assembly on the properties of cellulose composite networks and support the role of pectin in the mechanics of cell walls.

Micromechanical model of biphasic biomaterials with internal adhesion: Application to nanocellulose hydrogel composites.

The mechanical properties of hydrated biomaterials are non-recoverable upon unconfined compression if adhesion occurs between the structural components in the material upon fluid loss and apparent plastic behaviour. We explore these micromechanical phenomena by introducing an aggregation force and a critical yield pressure into the constitutive biphasic formulation for transversely isotropic tissues. The underlying hypothesis is that continual fluid pressure build-up during compression temporarily supresses aggregation. Once compression stops and the pressure falls below some critical value, internal aggregation occurs over a time scale comparable to the poroelastic time. We demonstrate this model by predicting the mechanical response of bacterial nanocellulose hydrogel composites, which are promising biomaterials and a structural mimetic for the plant cell wall. Cross-linking of cellulose by xyloglucan creates an extensional resistance and substantially increases the compressive modulus under large compression and densification. In comparison, incorporating non-crosslinking arabinoxylan into the hydrogel has little effect on its mechanics at the strain rates investigated. These results assist in elucidating the mechanical role of these polysaccharides in the complex plant cell wall structure. They also suggest xyloglucan is a suitable candidate to tailor the stiffness of nanocellulose hydrogels in biomaterial design, which includes modulating cell-adhesion in tissue engineering applications. The model and overall approach may be utilised to characterise and design a myriad of biomaterials and mammalian tissues, particularly those with a fibrillar structure. STATEMENT OF SIGNIFICANCE: The mechanical properties of hydrated biomaterials can be non-recoverable upon compression due to increased adhesion occurring between the structural components in the material. Cellulose-hemicellulose composite hydrogels constitute a classical example of this phenomenon, since fibres can freely re-orient and adhere upon fluid loss to produce significant variations in the mechanical response to compression. Here, we model their micromechanics by introducing an aggregation force and a critical yield pressure into the constitutive formulation for transversely isotropic biphasic materials. The resulting model is easy to implement for routine characterization of this type of hydrated biomaterials through unconfined compression testing and produces physically meaningful and reproducible mechanical parameters.

Pectin impacts cellulose fibre architecture and hydrogel mechanics in the absence of calcium.

Pectin is a major polysaccharide in many plant cell walls and recent advances indicate that its role in wall mechanics is more important than previously thought. In this work cellulose hydrogels were synthesised in pectin solutions, as a biomimetic tool to investigate the influence of pectin on cellulose assembly and hydrogel mechanical properties. Most of the pectin (60-80%) did not interact at the molecular level with cellulose, as judged by small angle scattering techniques (SAXS and SANS). Despite the lack of strong interactions with cellulose, this pectin fraction impacted the mechanical properties of the hydrogels through poroelastic effects. The other 20-40% of pectin (containing neutral sugar sidechains) was able to interact intimately with cellulose microfibrils at the point of assembly. These results support the need to revise the role of pectin in cell wall architecture and mechanics, and; furthermore they assist the design of cellulose-based products through controlling the viscoelasticity of the fluid phase.

Estudio de utilización de psicofármacos en usuarios de la policlínica del Hospital Vilardebó con diagnóstico de esquizofrenia (años 2006 y 2016) / Study of the use of psychotropic drugs in users of the Vilardebó Hospital polyclinic with a diagnosis of schizophrenia (2006 and 2016)

El tratamiento farmacológico de demostrada eficacia en la esquizofrenia es el antipsicótico. Sin embargo, en muchas ocasiones se requiere medicación concomitante que depende de comorbilidades y efectos adversos. Se realizó un estudio cuantitativo, longitudinal, retrospectivo, considerando el año 2006 y 2016, en una población de usuarios con esquizofrenia de la Policlínica del Hospital Vilardebó, analizando los tratamientos con psicofármacos. Se diferenciaron los tratamientos según monoterapia antipsicótica y polifarmacia con 2 antipsicóticos, y polifarmacia con más de 2 antipsicóticos, antidepresivos, estabilizantes del humor, benzodiacepinas y anticolinérgicos. La población inicial en 2006 fue de 621 pacientes y 398 pacientes continuaban en tratamiento en 2016. Mantuvieron el trata-miento con antipsicóticos 377 pacientes; 184 mantuvieron benzodiacepinas; 59 se mantuvieron con anticolinérgicos; 49, con estabilizantes del humor y 47, con antidepresivos. La monoterapia antipsicótica se presentó en torno al 50 % de la población estudiada. Se deberían revisar aquellas prácticas que se infieren a partir de este estudio, como el uso prolongado de anticolinérgicos, benzodiacepinas, y polifarmacia con más de 2 antipsicóticos, que está extendida en los usuarios con esquizofrenia. El tratamiento con clozapina fue el más estable y no parece aumentar la mortalidad en estos pacientes

Antipsychotics are the proved effective therapy for schizophrenia. However, on many occasions, associated drugs are required depending on comorbidities and side effects. A retrospective longitudinal quantitative study of drug prescription for 2006 and 2016 in patients with schizophrenia diagnosis was carried out in an outpatient clinic at Hospital Vilardebó. Treatments were classified as antipsychotic monotherapy, two antipsychotic drugs polypharmacy and polypharmacy with two antipsychotic drugs, antidepressants, mood stabilizers, benzodiazepines and anticholinergic drugs. Initial population in 2006 included 621 patients, 398 were still being treated in 2016. Antipsychotic drugs were still being received in 377 patients, benzodiazepines in 184, anticholinergic drugs in 59, mood stabilizers in 49, and anti-depressants in 47. Antipsychotic monotherapy was 50% of the population. Those practices that can be inferred from this study, with lengthy use of anticholinergic drugs, benzodiazepines, and the use of more than 2 antipsychotic drugs in patients with schizophrenia diagnosis should be revised. Clozapine therapy was the most stable and does not seem to increase mortality.