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Introduction: The megalencephaly capillary malformation polymicrogyria (MCAP syndrome) results from mosaic gain-of-function PIK3CA variants. The main clinical features are macrocephaly, somatic overgrowth, neurodevelopmental delay and brain anomalies. Alpelisib (Vijoice) is a recently FDA-approved PI3Kα-specific inhibitor for patients with PIK3CA-related overgrowth spectrum (PROS). During its development, in patients with the MCAP subgroup of PROS, there was no specific, standardised evaluation of the effect on neuro-cognitive functioning. Moreover, it remains unknown if the molecule crosses the blood-brain barrier. Our objective is to evaluate the efficacy of a 24 month treatment with alpelisib on adaptive behaviour in patients with MCAP syndrome., Methods and Analysis: SESAM is an industry-sponsored two-period multicentre French academic phase II trial, with a 6-month double-blind, placebo-controlled period followed by an open-label period. The primary endpoint is a ≥4-point improvement in the Vineland II Adaptive Behaviour Scale (VABS), 24 months after treatment initiation. Secondary objectives are safety, VABS improvement at 6 months, impact on the quality of life, epilepsy and hypotonia. 20 patients aged 2 to 40 years with an MCAP diagnosis and neurodevelopmental disorders of various degrees, will be followed monthly in local centres, centrally assessed (clinical, biological, neuropsychological and functional evaluation) at baseline and every 6 months. Patients will be evaluated by volumetric MRI at baseline and at 24 months. An optional lumbar puncture will be performed to investigate blood-brain barrier crossing. Inclusions were completed by April 2024, with the end of follow-up in November 2026.Given the efficacy of alpelisib in patients with PROS, if the drug crosses the blood-brain barrier, we can expect a clinical benefit for patients with neurocognitive disorders., Ethics and Dissemination: Ethical approval was given by CPP Sud-Ouest et Outre-Mer I (reference: 2022-500197-34-01). Findings from this study will be disseminated via publication, reports and conference presentations., Trial Registration Number: NCT05577754., Competing Interests: Competing interests: A patent application ('BYL719 (alpelisib) for the use in the treatment of PIK3CA-related overgrowth spectrum' #WO2017140828A1) has been filed by INSERM (Institut National de la Santé et de la Recherche Médicale), Centre National De La Recherche Scientifique (CNRS), Université Paris Cité and Assistance Publique-Hôpitaux De Paris (AP-HP) for the use of BYL719 (alpelisib) in the treatment of PIK3CA-related overgrowth spectrum (PROS/CLOVES syndrome). Dr Canaud is the inventor. This patent is licensed to Novartis Pharmaceutical. ML has received consulting fees from Novartis Pharmaceutical. GC receives or has received consulting fees from Novartis Pharmaceutical, Fresenius Medical Care, Vaderis, Alkermes, IPSEN and BridgeBio., (© Author(s) (or their employer(s)) 2024. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ Group.)

To advance the concept of a circular economy, fungal mycelium-based materials are drawing increased attention as substitutes for nonsustainable materials, such as petroleum-based and animal-derived products, due to their biodegradability, low carbon footprint, and cruelty-free nature. Addressing the challenge of mechanical properties in fungal mycelium products, this study presents a straightforward approach for reinforcing fungal mycelium mats. This is achieved by using two bio-based and biodegradable polymers, poly(3-hydroxybutyrate- co -3-hydroxyhexanoate) (PHBH) and polylactic acid (PLA), via material extrusion additive manufacturing (MEX AM), commonly known as 3D printing, to produce fungal mycelium-biopolymer composites. By analyzing the mechanical properties, roughness, and morphology, this study demonstrates significant improvements in ultimate tensile strength with the application of PHBH and even more with PLA, while elasticity is reduced. The study also discusses potential improvements to enhance the quality of the fungal mycelium-biopolymer composites without trading off bio-based and biodegradable features, offering a promising pathway for the development of more durable and sustainable fungal mycelium products., Competing Interests: The authors declare no competing financial interest., (© 2024 The Authors. Published by American Chemical Society.)

Recent advances in tissue engineering have been remarkable, yet the precise control of cellular behavior in 2D and 3D cultures remains challenging. One approach to address this limitation is to genomically engineer optogenetic control of cellular processes into tissues using gene switches that can operate with only a few genomic copies. Here, we implement blue and red light-responsive gene switches to engineer genomically stable two- and three-dimensional mammalian tissue models. Notably, we achieve precise control of cell death and morphogen-directed patterning in 2D and 3D tissues by optogenetically regulating cell necroptosis and synthetic WNT3A signaling at high spatiotemporal resolution. This is accomplished using custom-built patterned LED systems, including digital mirrors and photomasks, as well as laser techniques. These advancements demonstrate the capability of precise spatiotemporal modulation in tissue engineering and open up new avenues for developing programmable 3D tissue and organ models, with significant implications for biomedical research and therapeutic applications., Competing Interests: Competing interests: The authors declare no competing interests., (© 2024. The Author(s).)

Speech-language pathologists need to accurately identify structures/landmarks on swallow imaging. Foundational learning begins in graduate training. This study aimed to determine graduate student accuracy at identifying anatomical structures/landmarks during swallow evaluations and to determine if accuracy was predicted by type of imaging, anatomical structure, case type (i.e., normal/abnormal). Researchers recruited first-year graduate speech-language pathology students. Each participant reviewed five static images from lateral radiographic swallow studies and five static images from endoscopic swallow studies across 10 cases. Participants identified key anatomic structures and landmarks by clicking on the structure/landmark within a web-based platform. Two experienced speech-language pathologists reviewed and coded participant responses for accuracy. Sixteen graduate speech-language pathology students participated in a within-subjects design. Overall participant accuracy in identification of structure/landmarks was 69% (range 46%-88%). Binomial logistic regression was performed to study the effects of anatomical structure, case type (i.e., normal/abnormal), and image type on likelihood of participant accuracy in identifying anatomical structures (X 2 (4) = 143.65, p < 0.001). Only anatomical structure was statistically significant (X 2 (4) = 187.729, p < 0.001). The model explained 23.2% (Nagelkerke's R squared) of the variance in accuracy and correctly classified 78.4% of cases. Sensitivity was 92.1%, specificity was 47.3%, positive predictive value was 79.84%, and negative predictive value was 72.50%. The area under the ROC curve was 0.754, 95% CI [0.716, 0.791]. Graduate student's ability to correctly identify structures/landmarks overall was lower than desired and accuracy varied per structure. Results have implications for improving graduate student training for identification of structures/landmarks on swallow imaging., (© 2024 American Association for Anatomy.)

Stem cells in plant meristems are kept undifferentiated by signals from surrounding cells and provide the basis for continuous organ formation. In the stem cell organizer of the Arabidopsis thaliana root, the quiescent centre (QC), the WOX5 transcription factor, functions as a central hub in regulating columella stem cell (CSC) homoeostasis. However, the processes mediating WOX5 function are only poorly understood. Here we identify the transcription factor HAN as a central mediator of WOX5-regulated stem cell maintenance. HAN is required for mitotic quiescence of QC and CSC maintenance and is sufficient to induce ectopic stem cells. WOX5 and HAN repress transcription of the differentiation factor gene CDF4 in a coherent feed-forward loop (cFFL), one output of which is the expression of the auxin biosynthesis gene TAA1 and maintenance of auxin response maxima in the organizer. These findings and mathematical modelling provide a mechanistic framework for WOX5 function in the root stem cell niche., Competing Interests: Competing interests The authors declare no competing interests., (© 2024. The Author(s), under exclusive licence to Springer Nature Limited.)

Objectives: This study utilized non-linear finite element (FE) models to explore polymerization shrinkage and its impact on marginal integrity in molars following both selective caries removal (SCR) and conventional treatment. Specifically, we performed 2D in silico simulations to study residual stresses post-resin polymerization shrinkage and their influence on the marginal integrity of various restoration types., Methods: Initially, FE models were developed based on a cohesive zone framework to simulate crack propagation along the bonded interfaces between restoration and tooth structure in SCR-treated molars with class I and class II restorations. The modeled resin composite restorations first underwent polymerization shrinkage and were then subjected to various occlusal loading conditions. Stress magnitudes and distributions were identified to evaluate the margin integrity and predict the mechanism and location of interfacial failure., Results and Discussion: The FE models computed polymerization shrinkage stresses of less than 1 MPa, exerting a minor influence on the composite/tooth interface. Occlusal loading, however, significantly impacted the load-bearing capacity of the composite/tooth (c/t) interface, potentially jeopardizing the restoration integrity. Especially under bi-axial occlusal loading, interfacial debonding occurred in the vertical cavity walls of the class I restorations, increasing the risk of failure. Notably, SCR-treated teeth exhibited better margin integrity than restored teeth after complete caries removal (NCR). These findings provide valuable insights into the mechanical behavior of SCR-treated teeth under different loading conditions and highlight the importance of considering the load scenarios that may lead to failure at the c/t interface. By investigating the factors influencing crack initiation and delamination, this novel research contributes to the optimization of restorative treatments and aids in the design of more resilient dental restorations., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Humanity is often fascinated by structures and materials developed by Nature. While structural materials such as wood have been widely studied, the structural and mechanical properties of fungi are still largely unknown. One of the structurally interesting fungi is the polypore Fomes fomentarius. The present study deals with the investigation of the light but robust fruiting body of F. fomentarius. The four segments of the fruiting body (crust, trama, hymenium, and mycelial core) were examined. The comprehensive analysis included structural, chemical, and mechanical characterization with particular attention to cell wall composition, such as chitin/chitosan and glucan content, degree of deacetylation, and distribution of trace elements. The hymenium exhibited the best mechanical properties even though having the highest porosity. Our results suggest that this outstanding strength is due to the high proportion of skeletal hyphae and the highest chitin/chitosan content in the cell wall, next to its honeycomb structure. In addition, an increased calcium content was found in the hymenium and crust, and the presence of calcium oxalate crystals was confirmed by SEM-EDX. Interestingly, layers with different densities as well as layers of varying calcium and potassium depletion were found in the crust. Our results show the importance of considering the different structural and compositional characteristics of the segments when developing fungal-inspired materials and products. Moreover, the porous yet robust structure of hymenium is a promising blueprint for the development of advanced smart materials., Competing Interests: The authors have declared that no competing interests exist., (Copyright: © 2024 Klemm et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

Failure-resistant designs are particularly crucial for bones subjected to rapid loading, as is the case for the ambush-hunting northern pike (Esox lucius). These fish have slim and low-density osteocyte-lacking bones. As part of the swallowing mechanism, the cleithrum bone opens and closes the jaw. The cleithrum needs sufficient strength and damage tolerance, to withstand years of repetitive rapid gape-and-suck cycles of feeding. The thin wing-shaped bone comprises anisotropic layers of mineralized collagen fibers that exhibit periodic variations in mineral density on the mm and micrometer length scales. Wavy collagen fibrils interconnect these layers yielding a highly anisotropic structure. Hydrated cleithra exhibit Young's moduli spanning 3-9 GPa where the yield stress of ∼40 MPa increases markedly to exceed ∼180 MPa upon drying. This 5x observation of increased strength corresponds to a change to brittle fracture patterns. It matches the emergence of compressive residual strains of ∼0.15% within the mineral crystals due to forces from shrinking collagen layers. Compressive stresses on the nanoscale, combined with the layered anisotropic microstructure on the mm length scale, jointly confer structural stability in the slender and lightweight bones. By employing a range of X-ray, electron and optical imaging and mechanical characterization techniques, we reveal the structure and properties that make the cleithra impressively damage resistant composites. STATEMENT OF SIGNIFICANCE: By combining structural and mechanical characterization techniques spanning the mm to the sub-nanometer length scales, this work provides insights into the structural organization and properties of a resilient bone found in pike fish. Our observations show how the anosteocytic bone within the pectoral gridle of these fish, lacking any biological (remodeling) repair mechanisms, is adapted to sustain natural repeated loading cycles of abrupt jaw-gaping and swallowing. We find residual strains within the mineral apatite nanocrystals that contribute to forming a remarkably resilient composite material. Such information gleaned from bony structures that are different from the usual bones of mammals showcases how nature incorporates smart features that induce damage tolerance in bone material, an adaptation acquired through natural evolutionary processes., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

Plasma electrolytic oxidation (PEO), applied to light metals such as titanium, aluminum, and magnesium, creates a two-layer coating and has become increasingly important in metal coatings. However, due to the high voltage and temperature of the process, no online instrument could monitor the underlying mechanism. This paper presents a new image proving that the surface of PEO-coated Mg3ZnCa boiled during the process and argues that three hypotheses are involved in the PEO mechanism based on boiling caused by tolerating high voltage during the PEO process, which could explain the current‒voltage diagram of the process. Finally, nanoindentation was used to measure the elastic module and hardness of the PEO layers. The nanoindentation test results revealed the similarity of the elastic module of the outer porous layer and the primary alloy, with values of 40.25 GPa and 41.47 GPa, respectively, confirming that the outer porous layer corresponds to the cold plasma-gas phase formed during the PEO process., (© 2024. The Author(s).)

Trichome patterning in Arabidopsis is regulated by R2R3MYB , bHLH and WDR (MBW) genes. These are considered to form a trimeric MBW protein complex that promotes trichome formation. The MBW proteins are engaged in a regulatory network to select trichome cells among epidermal cells through R3MYB proteins that can move between cells and repress the MBW complex by competitive binding with the R2R3MYB to the bHLHL protein. We use quantitative pull-down assays to determine the relative dissociation constants for the protein-protein interactions of the involved genes. We find similar binding strength between the trichome promoting genes and weaker binding of the R3MYB inhibitors. We used the dissociation constants to calculate the relative percentage of all possible complex combinations and found surprisingly low fractions of those complexes that are typically considered to be relevant for the regulation events. Finally, we predict an increased robustness in patterning as a consequence of higher ordered complexes mediated by GL3 dimerization., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. The author(s) declared that they were an editorial board member of Frontiers, at the time of submission. This had no impact on the peer review process and the final decision., (Copyright © 2024 Zhang, Deneer, Fleck and Hülskamp.)

Microparticles have unique benefits in the formulation of multiparticulate and multi-unit type pharmaceutical dosage forms allowing improved drug safety and efficacy with favorable pharmacokinetics and patient centricity. On the other hand, the above advantages are served by high and well reproducible quality attributes of the medicinal product where even flexible design and controlled processability offer success as well as possible longer product life-cycle for the manufacturers. Moreover, the specific demands of patients can be taken into account, including simplified dosing regimens, flexible dosage, drug combinations, palatability, and ease of swallowing. In the more than 70 years since the first modified-release formulation appeared on the market, many new formulations have been marketed and many publications have appeared in the literature. More unique and newer pharmaceutical technologies and excipients have become available for producing tailor-made particles with micrometer dimensions and beyond. All these have contributed to the fact that the sub-units (e.g. minitablets, pellets, microspheres) that make up a multiparticulate system can vary widely in composition and properties. Some units have mucoadhesive properties and others can float to contribute to a suitable release profile that can be designed for the multiparticulate formula as a whole. Nowadays, there are some available formulations on the market, which are able to release the active substance even for several months (3 or 6 months depending on the type of treatment). In this review, the latest developments in technologies that have been used for a long time are presented, as well as innovative solutions such as the applicability of 3D printing to produce subunits of multiparticulate systems. Furthermore, the diversity of multiparticulate systems, different routes of administration are also presented, touching the ones which are capable of carrying the active substance as well as the relevant, commercially available multiparticle-based medical devices. The versatility in size from 1 µm and multiplicity of formulation technologies promise a solid foundation for the future applications of dosage form design and development., (Copyright © 2024 The Authors. Published by Elsevier B.V. All rights reserved.)

Bone material contains a hierarchical network of micro- and nano-cavities and channels, known as the lacuna-canalicular network (LCN), that is thought to play an important role in mechanobiology and turnover. The LCN comprises micrometer-sized lacunae, voids that house osteocytes, and submicrometer-sized canaliculi that connect bone cells. Characterization of this network in three dimensions is crucial for many bone studies. To quantify X-ray Zernike phase-contrast nanotomography data, deep learning is used to isolate and assess porosity in artifact-laden tomographies of zebrafish bones. A technical solution is proposed to overcome the halo and shade-off domains in order to reliably obtain the distribution and morphology of the LCN in the tomographic data. Convolutional neural network (CNN) models are utilized with increasing numbers of images, repeatedly validated by `error loss' and `accuracy' metrics. U-Net and Sensor3D CNN models were trained on data obtained from two different synchrotron Zernike phase-contrast transmission X-ray microscopes, the ANATOMIX beamline at SOLEIL (Paris, France) and the P05 beamline at PETRA III (Hamburg, Germany). The Sensor3D CNN model with a smaller batch size of 32 and a training data size of 70 images showed the best performance (accuracy 0.983 and error loss 0.032). The analysis procedures, validated by comparison with human-identified ground-truth images, correctly identified the voids within the bone matrix. This proposed approach may have further application to classify structures in volumetric images that contain non-linear artifacts that degrade image quality and hinder feature identification., (open access.)

Dry fruits and nutshells are biological capsules of outstanding toughness and strength with biomimetic potential to boost fiber-reinforced composites and protective structures. The strategies behind the Betholletia excelsa fruit mechanical performance were investigated with C-ring and compression tests. This last test was monitored with shearography and simulated with a finite element model. Microtomography and digital and scanning electron microscopy evaluated crack development. The fruit geometry, the preferential orientation of fibers involved in foam-like sclereid cells, promoted anisotropic properties but efficient energy dissipating mechanisms in different directions. For instance, the mesocarp cut parallel to its latitudinal section sustained higher forces (26.0 ± 2.8 kN) and showed higher deformation and slower crack propagation. The main toughening mechanisms are fiber deflection and fiber bridging and pullout, observed when fiber bundles are orthogonal to the crack path. Additionally, the debonding of fiber bundles oriented parallel to the crack path and intercellular cracks through sclereid and fiber cells created a tortuous path.

Hyaluronic acid (HA), also known as hyaluronan, is an anionic glycosaminoglycan widely distributed throughout various tissues of the human body. It stands out from other glycosaminoglycans as it lacks sulfation and can attain considerable size: the average human synovial HA molecule weighs about 7 million Dalton (Da), equivalent to roughly 20,000 disaccharide monomers; although some sources report a lower range of 3-4 million Da. In recent years, HA has garnered significant attention in the field of rheumatology due to its involvement in joint lubrication, cartilage maintenance, and modulation of inflammatory and/or immune responses. This review aims to provide a comprehensive overview of HA's involvement in rheumatology, covering its physiology, pharmacology, therapeutic applications, and potential future directions for enhancing patient outcomes. Nevertheless, the use of HA therapy in rheumatology remains controversial with conflicting evidence regarding its efficacy and safety. In conclusion, HA represents a promising therapeutic option to improve joint function and alleviate inflammation and pain.

Background: Serious or life-threatening pediatric emergencies are rare. Patient outcomes largely depend on excellent teamwork and require regular simulation-based team training. Recommendations for pediatric simulation-based education are scarce. We aimed to develop evidence-based guidelines to inform simulation educators and healthcare stakeholders., Methods: A modified three-round Delphi technique was used. The first guideline draft was formed through expert discussion and based on consensus ( n = 10 Netzwerk Kindersimulation panelists). Delphi round 1 consisted of an individual and team revision of this version by the expert panelists. Delphi round 2 comprised an in-depth review by 12 external international expert reviewers and revision by the expert panel. Delphi round 3 involved a revisit of the guidelines by the external experts. Consensus was reached after three rounds., Results: The final 23-page document was translated into English and adopted as international guidelines by the Swiss Society of Pediatrics (SGP/SSP), the German Society for Neonatology and Pediatric Intensive Care (GNPI), and the Austrian Society of Pediatrics., Conclusions: Our work constitutes comprehensive up-to-date guidelines for simulation-based team trainings and debriefings. High-quality simulation training provides standardized learning conditions for trainees. These guidelines will have a sustainable impact on standardized high-quality simulation-based education.

Electrospinning emerged as a promising technique to produce scaffolds for cultivated meat in function of its simplicity, versatility, cost-effectiveness, and scalability. Cellulose acetate (CA) is a biocompatible and low-cost material that support cell adhesion and proliferation. Here we investigated CA nanofibers, associated or not with a bioactive annatto extract (CA@A), a food-dye, as potential scaffolds for cultivated meat and muscle tissue engineering. The obtained CA nanofibers were evaluated concerning its physicochemical, morphological, mechanical and biological traits. UV-vis spectroscopy and contact angle measurements confirmed the annatto extract incorporation into the CA nanofibers and the surface wettability of both scaffolds, respectively. SEM images revealed that the scaffolds are porous, containing fibers with no specific alignment. Compared with the pure CA nanofibers, CA@A nanofibers showed increased fiber diameter (420 ± 212 nm vs. 284 ± 130 nm). Mechanical properties revealed that the annatto extract induces a reduction of the stiffness of the scaffold. Molecular analyses revealed that while CA scaffold favored C2C12 myoblast differentiation, the annatto-loaded CA scaffold favored a proliferative state of these cells. These results suggest that the combination of cellulose acetate fibers loaded with annatto extract may be an interesting economical alternative for support long-term muscle cells culture with potential application as scaffold for cultivated meat and muscle tissue engineering., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Santos, Cotta, Santos, Camargos, Carmo, Alcântara, Fleck, Copola, Nogueira, Silva, Andrade, Ferreira and Jorge.)

Trichomes are regularly distributed on the leaves of Arabidopsis thaliana. The gene regulatory network underlying trichome patterning involves more than 15 genes. However, it is possible to explain patterning with only five components. This raises the questions about the function of the additional components and the identification of the core network. In this study, we compare the relative expression of all patterning genes in A. thaliana, A. alpina and C. hirsuta by qPCR analysis and use mathematical modelling to determine the relative importance of patterning genes. As the involved proteins exhibit evolutionary conserved differential complex formation, we reasoned that the genes belonging to the core network should exhibit similar expression ratios in different species. However, we find several striking differences of the relative expression levels. Our analysis of how the network can cope with such differences revealed relevant parameters that we use to predict the relevant molecular adaptations in the three species., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Pietsch, Deneer, Fleck and Hülskamp.)

A significant proportion of pharmaceuticals are now considered multiparticulate systems. Modified-release drug delivery formulations can be designed with engineering precision, and patient-centric dosing can be accomplished relatively easily using multi-unit systems. In many cases, Multiple-Unit Pellet Systems (MUPS) are formulated on the basis of a neutral excipient core which may carry the layered drug surrounded also by functional coating. In the present summary, commonly used starter pellets are presented. The manuscript describes the main properties of the various nuclei related to their micro- and macrostructure. In the case of layered pellets formed based on different inert pellet cores, the drug release mechanism can be expected in detail. Finally, the authors would like to prove the industrial significance of inert cores by presenting some of the commercially available formulations.

While CRISPR-Cas defence mechanisms have been studied on a population level, their temporal dynamics and variability in individual cells have remained unknown. Using a microfluidic device, time-lapse microscopy and mathematical modelling, we studied invader clearance in Escherichia coli across multiple generations. We observed that CRISPR interference is fast with a narrow distribution of clearance times. In contrast, for invaders with escaping PAM mutations we found large cell-to-cell variability, which originates from primed CRISPR adaptation. Faster growth and cell division and higher levels of Cascade increase the chance of clearance by interference, while slower growth is associated with increased chances of clearance by priming. Our findings suggest that Cascade binding to the mutated invader DNA, rather than spacer integration, is the main source of priming heterogeneity. The highly stochastic nature of primed CRISPR adaptation implies that only subpopulations of bacteria are able to respond quickly to invading threats. We conjecture that CRISPR-Cas dynamics and heterogeneity at the cellular level are crucial to understanding the strategy of bacteria in their competition with other species and phages., (© 2022 The Authors. Published under the terms of the CC BY 4.0 license.)

Polymer based composites are widely used for treatment, for example as biofilm resistant seals of root canal fillings. Such clinical use, however, fails more frequently than other dental composite restorations, due to stress-related misfits. The reason for this is that the biomaterials used are inserted as viscous masses that may bond to the substrate, yet shrinkage stresses arising during setting of the cross-linking polymer, work against durable adhesion. Here we combine phase contrast enhanced time-lapse radiography (radioscopy), digital image correlation (DIC) and submicrometer resolution phase-contrast enhanced microtomography (PCE-CT), to reveal the spatial and temporal dynamics of composite polymerization and strain evolution. Radioscopy of cavities located in the upper part of human root canals demonstrates how the composite post-gelation "densification" is dominated by viscous flow with quantifiable motion of both particles and entrapped voids. Thereafter, these composites enter a "stress-relaxation" stage and exhibit several structural adaptations, induced by residual shrinkage stresses. Consequently critical alterations to the final biomaterial geometry emerge: (i) entrapped bubbles expand; (ii) microscopic root filling pull-out occurs; (iii) the cavity walls deform inwards, and (iv) occasionally delamination ensues, propagating out from the root canal filling along buried restoration-substrate interfaces. Our findings shed new light on the interactions between confined spaces and biomedical composites that cross-link in situ, highlighting the crucial role of geometry in channeling residual stresses. They further provide new insights into the emergence of structural flaws, calling attention to the need to find new treatment options. STATEMENT OF SIGNIFICANCE: This work quantifies recurring spatial and temporal material redistribution in composites used clinically to fill internal spaces in teeth. This knowledge is important for both promoting biomaterial resistance against potentially pathologic biofilms and for improving structural capacity to endure years of mechanical function. Our study demonstrates the significant role of geometry and the need for improved control over stress raisers to develop better treatment protocols and new space filling materials. The use of high-brilliance X-rays for time-lapse imaging at submicrometer resolution provides dynamic information about the damaging effects of stress relaxation due to polymerization shrinkage., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2021. Published by Elsevier Ltd.)

Background: Filamentous fungi of the phylum Basidiomycota are considered as an attractive source for the biotechnological production of composite materials. The ability of many basidiomycetes to accept residual lignocellulosic plant biomass from agriculture and forestry such as straw, shives and sawdust as substrates and to bind and glue together these otherwise loose but reinforcing substrate particles into their mycelial network, makes them ideal candidates to produce biological composites to replace petroleum-based synthetic plastics and foams in the near future., Results: Here, we describe for the first time the application potential of the tinder fungus Fomes fomentarius for lab-scale production of mycelium composites. We used fine, medium and coarse particle fractions of hemp shives and rapeseed straw to produce a set of diverse composite materials and show that the mechanical materials properties are dependent on the nature and particle size of the substrates. Compression tests and scanning electron microscopy were used to characterize composite material properties and to model their compression behaviour by numerical simulations. Their properties were compared amongst each other and with the benchmark expanded polystyrene (EPS), a petroleum-based foam used for thermal isolation in the construction industry. Our analyses uncovered that EPS shows an elastic modulus of 2.37 ± 0.17 MPa which is 4-times higher compared to the F. fomentarius composite materials whereas the compressive strength of 0.09 ± 0.003 MPa is in the range of the fungal composite material. However, when comparing the ability to take up compressive forces at higher strain values, the fungal composites performed better than EPS. Hemp-shive based composites were able to resist a compressive force of 0.2 MPa at 50% compression, rapeseed composites 0.3 MPa but EPS only 0.15 MPa., Conclusion: The data obtained in this study suggest that F. fomentarius constitutes a promising cell factory for the future production of fungal composite materials with similar mechanical behaviour as synthetic foams such as EPS. Future work will focus on designing materials characteristics through optimizing substrate properties, cultivation conditions and by modulating growth and cell wall composition of F. fomentarius, i.e. factors that contribute on the meso- and microscale level to the composite behaviour., (© 2022. The Author(s).)

Mathematical modelling techniques are integral to current research in plant synthetic biology. Modelling approaches can provide mechanistic understanding of a system, allowing predictions of behaviour and thus providing a tool to help design and analyse biological circuits. In this chapter, we provide an overview of mathematical modelling methods and their significance for plant synthetic biology. Starting with the basics of dynamics, we describe the process of constructing a model over both temporal and spatial scales and highlight crucial approaches, such as stochastic modelling and model-based design. Next, we focus on the model parameters and the techniques required in parameter analysis. We then describe the process of selecting a model based on tests and criteria and proceed to methods that allow closer analysis of the system's behaviour. Finally, we highlight the importance of uncertainty in modelling approaches and how to deal with a lack of knowledge, noisy data, and biological variability; all aspects that play a crucial role in the cooperation between the experimental and modelling components. Overall, this chapter aims to illustrate the importance of mathematical modelling in plant synthetic biology, providing an introduction for those researchers who are working with or working on modelling techniques., (© 2022. Springer Science+Business Media, LLC, part of Springer Nature.)

Purpose: PIK3CA pathogenic variants in the PIK3CA-related overgrowth spectrum (PROS) activate phosphoinositide 3-kinase signaling, providing a rationale for targeted therapy, but no drug has proven efficacy and safety in this population. Our aim was to establish the six-month tolerability and efficacy of low-dose taselisib, a selective class I PI3K inhibitor, in PROS patients., Methods: Patients over 16 years with PROS and PIK3CA pathogenic variants were included in a phase IB/IIA multicenter, open-label single-arm trial (six patients at 1 mg/day of taselisib, then 24 at 2 mg/day). The primary outcome was the occurrence of dose limiting toxicity (DLT). Efficacy outcomes were the relative changes after treatment of (1) tissue volume at affected and unaffected sites, both clinically and on imaging; (2) cutaneous vascular outcomes when relevant; (3) biologic parameters; (4) quality of life; and (5) patient-reported outcomes., Results: Among 19 enrolled patients, 2 experienced a DLT (enteritis and pachymeningitis) leading to early trial termination (17 treated, 10 completed the study). No serious adverse reaction occurred in the 1 mg cohort (n = 6). No significant reduction in affected tissue volume was observed (mean -4.2%; p = 0.81; SD 14.01). Thirteen (76.4%) participants reported clinical improvement (pain reduction, chronic bleeding resolution, functional improvement)., Conclusion: Despite functional improvement, the safety profile of low-dose taselisib precludes its long-term use., (© 2021. The Author(s).)

The investigational drugs circuit has specific risks, and medication errors may occur in clinical trials, possibly associated with adverse reactions. These risks must therefore be managed. In fact, there are few reports of medication errors during clinical trials. In a context of regulatory interpretation difficulties on this subject, we conducted a national survey that highlighted the heterogeneity of the methods used by academic sponsors to collect, code and report medication errors and the need to develop a culture of reporting these errors in clinical trials. This is why the REVISE group (safety officers of French institutional sponsors) has issued recommendations to clarify the sponsor and investigator responsibilities and guide them in the management of medication errors. These new guidelines recommend that any serious or potentially serious medication error or other "special situation" (e.g. overdose, misuse, quality defect) should be notified immediately to the sponsor by the investigator. The clinical research pharmacist place is strategic to detect medication errors and other special situations. The integration of the pharmacist into the reporting system, in collaboration with the investigator, could be discussed with clinical research professionals and health authorities., (Copyright © 2021 Société française de pharmacologie et de thérapeutique. Published by Elsevier Masson SAS. All rights reserved.)

In the course of a lifetime the crowns of teeth wear off, cementum thickens and the pulp closes-in or may stiffen. Little is known about how these changes affect the tooth response to load. Using a series of finite element models of teeth attached to the jawbone, and by comparing these to a validated model of a 'young' pig 3-rooted tooth, the effects of these structural changes were studied. Models of altered teeth show a stiffer response to mastication even when material properties used are identical to those found in 'young' teeth. This stiffening response to occlusal loads is mostly caused by the thicker cementum found in 'old' teeth. Tensile stresses associated with bending of dentine in the roots fall into a narrower distribution range with lower peak values. It is speculated that this is a possible protective adaptation mechanism of the aging tooth to avoid fracture. The greatest reduction in lateral motion was seen in the bucco-lingual direction. We propose that greater tooth motion during mastication is typical for the young growing animal. This motion is reduced in adulthood, favoring less off-axis loading, possibly to counteract natural bone resorption and consequent compromised anchoring., (Copyright © 2021. Published by Elsevier Inc.)

Quantitative plant biology is an interdisciplinary field that builds on a long history of biomathematics and biophysics. Today, thanks to high spatiotemporal resolution tools and computational modelling, it sets a new standard in plant science. Acquired data, whether molecular, geometric or mechanical, are quantified, statistically assessed and integrated at multiple scales and across fields. They feed testable predictions that, in turn, guide further experimental tests. Quantitative features such as variability, noise, robustness, delays or feedback loops are included to account for the inner dynamics of plants and their interactions with the environment. Here, we present the main features of this ongoing revolution, through new questions around signalling networks, tissue topology, shape plasticity, biomechanics, bioenergetics, ecology and engineering. In the end, quantitative plant biology allows us to question and better understand our interactions with plants. In turn, this field opens the door to transdisciplinary projects with the society, notably through citizen science., Competing Interests: The authors declare that there is no conflict of interest., (© The Author(s), 2021. Published by Cambridge University Press in association with The John Innes Centre 2021.)

Brazil nut (Bertholletia excelsa) fruits are capable of resisting high mechanical forces when released from trees as tall as 50 m, as well as during animal dispersal by sharp-teethed rodents. Thick mesocarp plays a crucial part in seed protection. We investigated the role of microstructure and how sclereids, fibers, and voids affect nutshell performance using compression, tensile and fracture toughness tests. Fractured specimens were analyzed through scanning electron microscopy (SEM) and microtomography (microCT). Mesocarp showed high deformability (strain at max. stress of ~30%) under compression loading, a critical tensile strength of ~24.9 MPa, a Weibull modulus of ~3, and an elastic modulus of ~2 GPa in the tensile test. The fracture toughness, estimated through the work of fracture of SENB tests, reached ~2 kJ/m 2 . The thick and strong walls of mesocarp cells, with a weaker boundary between them (compound middle lamella), promote a tortuous intercellular crack path. Several toughening mechanisms, such as crack deflection, breaking of fiber bundles, fiber pullout and bridging as well as crack branching, occur depending on how fiber bundles and voids are oriented., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

Objectives: Selective caries removal (SCR) is recommended over non-selective removal for managing deep carious lesions to avoid pulp exposure and maintain pulp vitality. During SCR, residual carious dentin is left behind and sealed beneath the restoration. The biomechanical effects of such residual lesions on the restored tooth remain unclear and were assessed using finite element modeling (FEM)., Methods: Based on μ-CT images of a healthy permanent human third molar, we developed five finite element models. Generic class I and II cavity restorations were modeled where residual lesions of variable sizes were either left or fully removed on occlusal and proximal surfaces. The cavities were restored with adhesive composite. All 3D-FE models were compared with a model of a healthy, non-treated molar. A vertical load of 100 N was applied onto the occlusal surface., Results: Regardless of the lesion size, in molars with occlusal lesions higher mean stresses were predicted along the filling-lesion interface than in all other models. The smallest occlusal lesion (Ø 1 = 1 mm) resulted in the highest maximum stresses at the filling-lesion interface with large stress concentrations at the filling walls indicating failure risk. In conclusion, lesion site and extent are influencing parameters affecting the filling-lesion interactions and thus the biomechanical behavior of the tooth after SCR., Significance: Retaining carious lesions around the pulpal floor affects the deformation and stress states in tooth-filling complexes. The higher stresses observed in molars with occlusal lesions may affect restoration stability and longevity. Suprisingly, more extended occlusal lesions may provide a more favorable tooth performance than less extended ones. In contrast, in molars with proximal lesions the residual lesion had only limited effect on the tooth's biomechanical condition., (Copyright © 2020 The Academy of Dental Materials. Published by Elsevier Inc. All rights reserved.)

Infant attachment is theorized to lay the foundation of emotion regulation across the life span. However, testing this proposition requires prospective designs examining whether attachment assessed in infancy predicts emotion regulation strategies observed in adult relationships. Using unique data from the Minnesota Longitudinal Study of Risk and Adaptation, we examined whether infant attachment assessed at 12 and 18 months in the Strange Situation were associated with attachment-relevant emotion regulation strategies coded from video-recorded conflict discussions with romantic partners at ages 20, 23, 26, and/or 35. The current research first integrated the developmental and emotion regulation literatures to identify three specific attachment-relevant emotion regulation strategies. Balanced-regulation involves being open, approach-orientated, and engaging in collaborative problem-solving. Hypo-regulation involves suppressing emotions, disengaging from close others, and engaging in superficial problem-solving. Hyper-regulation involves exaggerating emotional expressions, ruminating, and being self-focused in processing issues. Compared to stable secure infants (secure at 12 and 18 months), stable insecure infants (insecure at 12 and 18 months) displayed worse balanced-regulation and greater hypo-regulation strategies, and unstable insecure infants (insecure at 12 or 18 months) displayed greater hyper-regulation strategies, in relationship-threatening situations 20-35 years later. Conceptually replicating these results, greater friendship insecurity at age 16 predicted worse balanced-regulation and greater hypo- and hyper-regulation strategies during relationship-threatening situations in adulthood. These findings highlight that infant attachment insecurity is associated with distinct emotion regulation strategies in adulthood 20-35 years later. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

Constraint-based, genome-scale metabolic models are an essential tool to guide metabolic engineering. However, they lack the detail and time dimension that kinetic models with enzyme dynamics offer. Model reduction can be used to bridge the gap between the two methods and allow for the integration of kinetic models into the Design-Built-Test-Learn cycle. Here we show that these reduced size models can be representative of the dynamics of the original model and demonstrate the automated generation and parameterisation of such models. Using these minimal models of metabolism could allow for further exploration of dynamic responses in metabolic networks., (Copyright © 2021 The Authors. Published by Elsevier Inc. All rights reserved.)

Bone-like materials comprise carbonated-hydroxyapatite nanocrystals (c-Ap) embedding a fibrillar collagen matrix. The mineral particles stiffen the nanocomposite by tight attachment to the protein fibrils creating a high strength and toughness material. The nanometer dimensions of c-Ap crystals make it very challenging to measure their mechanical properties. Mineral in bony tissues such as dentine contains 2~6 wt.% carbonate with possibly different elastic properties as compared with crystalline hydroxyapatite. Here we determine strain in biogenic apatite nanocrystals by directly measuring atomic deformation in pig dentine before and after removing carbonate. Transmission electron microscopy revealed the platy 3D morphology while atom probe tomography revealed carbon inside the calcium rich domains. High-energy X-ray diffraction in combination with in situ hydrostatic pressurization quantified reversible c-Ap deformations. Crystal strains differed between annealed and ashed (decarbonated) samples, following 1 or 10 h heating at 250 °C or 550 °C respectively. Measured bulk moduli (K) and a-/c-lattice deformation ratios (η) were used to generate synthetic K syn and η syn identifying the most likely elastic constants C 33 and C 13 for c-Ap. These were then used to calculate the nanoparticle elastic moduli. For ashed samples, we find an average E 11 =107 GPa and E 33  =128 GPa corresponding to ~5% and ~17% stiffening of the a-/c-axes of the nanocrystals as compared with the biogenic nanocrystals in annealed samples. Ashed samples exhibit ~10% lower Poisson's ratios as compared with the 0.25~0.36 range of carbonated apatite. Carbonate in c-Ap may therefore serve for tuning local deformability within bony tissues. STATEMENT OF SIGNIFICANCE: Carbonated apatite nanoparticles, typical for bony tissues, stiffen the network of collagen fibrils. However, it is not known if the biogenic apatite mechanical (elastic) properties differ from those of geologic mineral counterparts. Indeed the tiny dimensions and variable carbonate composition may have strong effects on deformation resistance. The present study provides experimental measurements of the elastic constants which we use to estimate Young's moduli and Poisson's ratio values. Comparison between ashed and annealed dentine samples quantifies the properties of both carbonated and decarbonated apatite nanocrystals. The results reveal fundamental attributes of bony mineral and showcase the additive advantages of combining X-ray diffraction with in situ hydrostatic compression, backed by atom probe and transmission electron microscopy tomography., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.)

The intensive use of groundwater in agriculture under the current climate conditions leads to acceleration of soil salinization. Given that almond is a salt-sensitive crop, selection of salt-tolerant rootstocks can help maintain productivity under salinity stress. Selection for tolerant rootstocks at an early growth stage can reduce the investment of time and resources. However, salinity-sensitive markers and salinity tolerance mechanisms of almond species to assist this selection process are largely unknown. We established a microscopy-based approach to investigate mechanisms of stress tolerance in and identified cellular, root anatomical, and molecular traits associated with rootstocks exhibiting salt tolerance. We characterized three almond rootstocks: Empyrean-1 (E1), Controller-5 (C5), and Krymsk-86 (K86). Based on cellular and molecular evidence, our results show that E1 has a higher capacity for salt exclusion by a combination of upregulating ion transporter expression and enhanced deposition of suberin and lignin in the root apoplastic barriers, exodermis, and endodermis, in response to salt stress. Expression analyses revealed differential regulation of cation transporters, stress signaling, and biopolymer synthesis genes in the different rootstocks. This foundational study reveals the mechanisms of salinity tolerance in almond rootstocks from cellular and structural perspectives across a root developmental gradient and provides insights for future screens targeting stress response., Competing Interests: The reviewer JS declared a shared affiliation, with no collaboration, with one of the authors TD to the handling editor at the time of the review. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2021 Shao, Cheng, Pang, Chang, He, Wang, Davis, Zhang, Betz, Fleck, Dai, Madahhosseini, Wilkop, Jernstedt and Drakakaki.)

The regular distribution of trichomes on leaves in Arabidopsis is a well-understood model system for two-dimensional pattern formation. It involves more than 10 genes and is governed by two patterning principles, the activator-inhibitor (AI) and the activator-depletion (AD) mechanisms, though their relative contributions are unknown. The complexity of gene interactions, protein interactions, and intra- and intercellular mobility of proteins makes it very challenging to understand which aspects are relevant for pattern formation. In this study, we use global mathematical methods combined with a constraining of data to identify the structure of the underlying network. To constrain the model, we perform a genetic, cell biological, and biochemical study of weak ttg1 alleles. We find that the core of trichome patterning is a combination of AI and AD mechanisms differentiating between two pathways activating the long-range inhibitor CPC and the short-range inhibitor TRY., Competing Interests: Declaration of Interests The authors declare no competing interests., (Copyright © 2020 The Authors. Published by Elsevier Inc. All rights reserved.)

Live cell imaging has tremendously promoted our understanding of cellular and subcellular processes such as cell division. Here, we present a step-by-step protocol for a robust and easy-to-use live cell imaging approach to study male meiosis in the plant Arabidopsis thaliana as recently established. Our method relies on the concomitant analysis of two reporter genes that highlight chromosome configurations and microtubule dynamics. In combination, these reporter genes allowed the discrimination of five cellular parameters: cell shape, microtubule array, nucleus position, nucleolus position, and chromatin condensation. These parameters can adopt different states, e.g. , the nucleus position can be central or lateral. Analyzing how tightly these states are associated gives rise to landmark stages that in turn allow a quantitative and qualitative dissection of meiotic progression. We envision that such an approach can also provide valuable criteria for the analysis of cell differentiation processes outside of meiosis., Competing Interests: Competing interestsArp Schnittger on behalf of all authors confirms that none of the authors has competing financial interests in this work., (Copyright © The Authors; exclusive licensee Bio-protocol LLC.)

Aiming to understand Nature´s strategies that inspire new composite materials, the hierarchical levels of organization of the Brazil nut (Bertholletia excelsa) mesocarp were investigated. Optical microscopy, scanning electron microscopy (SEM), microtomography (MicroCT) and small-angle X-ray scattering (SAXS) were used to deeply describe the cellular and fibrillary levels of organization. The mesocarp is the middle layer of the fruit which has developed several strategies to avoid its opening and protect its seed. Fibers have a different orientation in the three layers of the mesocarp, what reduces the anisotropy of the structure. Sclereids cells with thick cell walls fill the spaces between the fibers resembling a foam-filled structural composite. The mesocarp has several tubular channels and fractured surfaces which may work as sites for crack trapping and increase toughness. The thick and lignified cell wall of sclereids and fibers and the weak interface between cells can promote a longer and tortuous intercellular crack path. Additionally, fibers with high strength and stiffness due to microfibrils oriented along the main cell axis (µ = 0° to 17°) were identified in the innermost layer of the mesocarp. Such an understanding of each hierarchical level can inspire the development of new cellular composites with improved mechanical behavior.

Teeth with intact crowns rarely split or fracture, despite decades of cyclic loading and occasional unexpected overload. This is largely attributed to the presence of dentine, since cracking and fracture of enamel have been frequently reported. Dentine is similar to bone, comprising mineralised collagen fibres as a main constituent. Unlike cortical bone, however, where microcracking and damage arrest are essential for re/modelling and healing, dentine can neither remodel nor regenerate. This raises questions regarding the evolutionary benefits of toughening, leading to uncertainty whether cracks actually appear in dentine in situ. Here we study the notion that circumpulpal dentine is usually protected against, rather than damaged by severe overloads, even though it is not much more massive or stronger than it needs to be. To address this, we examined hydrated teeth still within whole jawbones of freshly-slaughtered skeletally mature pigs, mechanically loaded until fracture. Force displacement curves, optical and electron microscopy combined with 3D microstructural analysis by conventional micro-computed tomography (μCT) revealed mostly brittle fracture paths in circumpulpal crown dentine. Once overload cracks reach this mass of dentine they propagate rapidly along straight paths often parallel to the enamel flanks of the oblong shovel shaped premolars. We find infrequent signs of active toughening mechanisms with minimal crack diversion, ligament bridging and microcracking. When such toughening is seen, it mainly appears in softer dentine in the root, or near the dentine-enamel-junction (DEJ) in mantle dentine. We observed shear bands in overloaded circumpulpal dentine, due to mutual gliding of upper and lower segments. These shear bands are formed as periodic arrays of rotated dentine fragments. The 3D data consistently demonstrate the importance of the layered tooth structure, containing a stiff outer enamel shell, a soft sub-DEJ interlayer and a stiff circumpulpal dentine bulk, for deflecting cracks from splitting the tooth., (Copyright © 2019 Elsevier Inc. All rights reserved.)

In the present study, Mg nanocomposites with a high volume fraction (10 vol %) of SiC particles were fabricated by two approaches: mechanical milling and mixing, followed by the powder consolidation steps, including isostatic cold pressing, sintering, and extrusion. A uniform distribution of the high content SiC particles in a fully dense Mg matrix with ultrafine microstructure was successfully achieved in the mechanically milled composites. The effect of nano- and submicron-sized SiC particles on the microstructure and mechanical properties of the nanocomposites was evaluated. Scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive spectrometer (EDS), and X-ray diffractometry (XRD) were used to characterize microstructures of the milled and mixed composites. Mechanical behavior of the Mg composites was studied under nanoindentation and compressive loading to understand the effects the microstructural modification on the strength and ductility of the Mg/SiC composites. The mechanical properties of the composites showed a significant difference regarding the size and distribution of SiC particles in the Mg matrix. The enhanced strength and superior ductility achieved in the mechanically milled Mg composites are mainly ascribed to the effective load transfer between matrix and SiC particles, grain refinement of the matrix, and strengthening effects of the nano- and submicron-sized SiC particles., Competing Interests: The authors declare no conflict of interest.

Aiming to produce bioinspired impact and puncture resistant materials, the mesocarp of the Brazil nut (Bertholletia excelsa) was characterized. The mesocarp composition was investigated by chemical extraction and its microstructure was analyzed by optical microscopy and microtomography (microCT). A compression test evaluated the force needed to open the mesocarp shell. Shore D hardness testing and nanoindentation measured the local mechanical properties at different length scales. Brazil nut mesocarp has a higher content of lignin (56%) than other nutshells and is mainly composed of sclereids and fibers cells arranged together and not in separated layers as usually found in nature. The mesocarp has an internal and external layer with fibers oriented from peduncle to opercular opening and a middle layer where entangled fibers are latitudinally oriented. To open a Brazil nut mesocarp, compression forces of 10 079  ±  1460 N (parallel to latitudinal section) and 14 785  ±  4050 N (perpendicular to latitudinal section) are needed. Such forces are higher than the forces needed to open most nutshells, if fracture force is normalized by shell thickness. The Shore D hardness test showed that hardness is uniform in the mesocarp, although it is higher in the center of the thickness than close to the inner or outer surface. The cell wall of fibers has a higher reduced modulus than the cell wall of sclereids although they have a similar hardness. These microstructural and mechanical results indicate that Brazil nutshell has great potential as a source for bioinspiration and motivates further studies.

Background: Non-tunneled hemodialysis catheters are currently used for critically ill patients with acute kidney injury requiring extracorporeal renal replacement therapy. Strategies to prevent catheter dysfunction and infection with catheter locks remain controversial., Methods: In a multicenter, randomized, controlled, double-blind trial, we compared two strategies for catheter locking of non-tunneled hemodialysis catheters, namely trisodium citrate at 4% (intervention group) versus unfractionated heparin (control group), in patients aged 18 years or older admitted to the intensive care unit and in whom a first non-tunneled hemodialysis catheter was to be inserted by the jugular or femoral vein. The primary endpoint was length of event-free survival of the first non-tunneled hemodialysis catheter. Secondary endpoints were: rate of fibrinolysis, incidence of catheter dysfunction and incidence of catheter-related bloodstream infection (CRBSI), all per 1000 catheter-days; number of hemorrhagic events requiring transfusion, length of stay in intensive care and in hospital; 28-day mortality., Results: Overall, 396 randomized patients completed the trial: 199 in the citrate group and 197 in the heparin group. There was no significant difference in baseline characteristics between groups. The duration of event-free survival of the first non-tunneled hemodialysis catheter was not significantly different between groups: 7 days (IQR 3-10) in the citrate group and 5 days (IQR 3-11) in the heparin group (p = 0.51). Rates of catheter thrombosis, CRBSI, and adverse events were not statistically different between groups., Conclusions: In critically ill patients, there was no significant difference in the duration of event-free survival of the first non-tunneled hemodialysis catheter between trisodium citrate 4% and heparin as a locking solution. Catheter thrombosis, catheter-related infection, and adverse events were not statistically different between the two groups. Trial registration Registered with Clinicaltrials.gov under the number NCT01962116. Registered 14 October 2013.

The genetic and molecular analysis of trichome development in Arabidopsis thaliana has generated a detailed knowledge about the underlying regulatory genes and networks. However, how rapidly these mechanisms diverge during evolution is unknown. To address this problem, we used an unbiased forward genetic approach to identify most genes involved in trichome development in the related crucifer species Arabis alpina In general, we found most trichome mutant classes known in A. thaliana We identified orthologous genes of the relevant A. thaliana genes by sequence similarity and synteny and sequenced candidate genes in the A. alpina mutants. While in most cases we found a highly similar gene-phenotype relationship as known from Arabidopsis , there were also striking differences in the regulation of trichome patterning, differentiation, and morphogenesis. Our analysis of trichome patterning suggests that the formation of two classes of trichomes is regulated differentially by the homeodomain transcription factor AaGL2 Moreover, we show that overexpression of the GL3 basic helix-loop-helix transcription factor in A. alpina leads to the opposite phenotype as described in A. thaliana Mathematical modeling helps to explain how this nonintuitive behavior can be explained by different ratios of GL3 and GL1 in the two species., Competing Interests: The authors declare no conflict of interest.

To follow the dynamics of meiosis in the model plant Arabidopsis, we have established a live cell imaging setup to observe male meiocytes. Our method is based on the concomitant visualization of microtubules (MTs) and a meiotic cohesin subunit that allows following five cellular parameters: cell shape, MT array, nucleus position, nucleolus position, and chromatin condensation. We find that the states of these parameters are not randomly associated and identify 11 cellular states, referred to as landmarks, which occur much more frequently than closely related ones, indicating that they are convergence points during meiotic progression. As a first application of our system, we revisited a previously identified mutant in the meiotic A-type cyclin TARDY ASYNCHRONOUS MEIOSIS ( TAM ). Our imaging system enabled us to reveal both qualitatively and quantitatively altered landmarks in tam , foremost the formation of previously not recognized ectopic spindle- or phragmoplast-like structures that arise without attachment to chromosomes., Competing Interests: MP, EK, Rv, SK, KM, EW, CF, AS No competing interests declared, FS is affiliated with CropSeq bioinformatics. The author has no other competing interests to declare, (© 2019, Prusicki et al.)

It is well known that the kinetics of an intracellular biochemical network is stochastic. This is due to intrinsic noise arising from the random timing of biochemical reactions in the network as well as due to extrinsic noise stemming from the interaction of unknown molecular components with the network and from the cell's changing environment. While there are many methods to study the effect of intrinsic noise on the system dynamics, few exist to study the influence of both types of noise. Here we show how one can extend the conventional linear-noise approximation to allow for the rapid evaluation of the molecule numbers statistics of a biochemical network influenced by intrinsic noise and by slow lognormally distributed extrinsic noise. The theory is applied to simple models of gene regulatory networks and its validity confirmed by comparison with exact stochastic simulations. In particular, we consider three important biological examples. First, we investigate how extrinsic noise modifies the dependence of the variance of the molecule number fluctuations on the rate constants. Second, we show how the mutual information between input and output of a network motif is affected by extrinsic noise. And third, we study the robustness of the ubiquitously found feed-forward loop motifs when subjected to extrinsic noise.

The immune system distinguishes between self and foreign antigens. The kinetic proofreading (KPR) model proposes that T cells discriminate self from foreign ligands by the different ligand binding half-lives to the T cell receptor (TCR). It is challenging to test KPR as the available experimental systems fall short of only altering the binding half-lives and keeping other parameters of the interaction unchanged. We engineered an optogenetic system using the plant photoreceptor phytochrome B (PhyB) as a ligand to selectively control the dynamics of ligand binding to the TCR by light. This opto-ligand-TCR system was combined with the unique property of PhyB to continuously cycle between the binding and non-binding states under red light, with the light intensity determining the cycling rate and thus the binding duration. Mathematical modeling of our experimental datasets showed that indeed the ligand-TCR interaction half-life is the decisive factor for activating downstream TCR signaling, substantiating KPR., Competing Interests: OY, MG, MH, JC, MW, SB, RS, CF, TK, MZ, TH, WW, WS No competing interests declared, (© 2019, Yousefi et al.)

The study of innovative biodegradable implant materials is one of the most interesting research topics at the forefront in the area of biomaterials. Biodegradable implant materials in the human body can be gradually dissolved, absorbed, consumed or excreted, so there is no need for the secondary surgery to remove implants after the surgery regions have healed. However, most of the biodegradable materials, usually polymers, do not have good mechanical properties to be reliable for bearing the load of the body. Magnesium and its alloys due to the excellent biodegradability and biocompatibility as well as the suitable mechanical compatibility with human bone are very promising candidates for the development of temporary, degradable implants in load-bearing applications. However, Mg alloys are corrosion susceptible in a biological environment. Besides, the high corrosion rate and the low bioactivity of magnesium implants are the challenging problems, which need to be resolved before employing them in clinical applications. This paper provides a review of state-of-the-art of magnesium alloy implants for orthopedic and tissue engineering applications and describes recent progress in the design of novel structure design Mg alloys and potential approaches to improve their biodegradation performance.

Vegetation shade is characterized by marked decreases in the red/far-red ratio and photosynthetic irradiance. The activity of phytochrome in the field has typically been described by its photoequilibrium, defined by the photochemical properties of the pigment in combination with the spectral distribution of the light. This approach represents an oversimplification because phytochrome B (phyB) activity depends not only on its photochemical reactions but also on its rates of synthesis, degradation, translocation to the nucleus, and thermal reversion. To account for these complex cellular reactions, we used a model to simulate phyB activity under a range of field conditions. The model provided values of phyB activity that in turn predicted hypocotyl growth in the field with reasonable accuracy. On the basis of these observations, we define two scenarios, one is under shade, in cloudy weather, at the extremes of the photoperiod or in the presence of rapid fluctuations of the light environment caused by wind-induced movements of the foliage, where phyB activity departs from photoequilibrium and becomes affected by irradiance and temperature in addition to the spectral distribution. The other scenario is under full sunlight, where phyB activity responds mainly to the spectral distribution of the light., (© 2018 John Wiley & Sons Ltd.)

Mathematical models are important tools in helping us to understand complex biological systems. Models of phytochrome-regulated systems in Arabidopsis thaliana have shown the importance of dimerization, nuclear transport, and thermal/dark reversion in mediating phytochrome activity and plant development. Here we go through the steps required to calculate the steady-state amounts of phytochrome subspecies relative to the total phytochrome molecule population. Starting from a simplified two-state system we expand and apply the technique to the extended phytochrome dimer model. Additionally, we provide a Python package that can automatically calculate the proportion of phytochrome B in a particular state given specific experimental conditions.

Herein, the chemical synthesis and binding analysis of functionalizable rigid and flexible core trivalent sialosides bearing oligoethylene glycol (OEG) spacers interacting with spike proteins of influenza A virus (IAV) X31 is described. Although the flexible Tris-based trivalent sialosides achieved micromolar binding constants, a trivalent binder based on a rigid adamantane core dominated flexible tripodal compounds with micromolar binding and hemagglutination inhibition constants. Simulation studies indicated increased conformational penalties for long OEG spacers. Using a systematic approach with molecular modeling and simulations as well as biophysical analysis, these findings emphasize on the importance of the scaffold rigidity and the challenges associated with the spacer length optimization., (© 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)