The Moderating Role of Family Communication in Suicidal Ideation and Victimization in Adolescents.

BACKGROUND: Traditional peer victimization and cyber-victimization are predictive risk factors for suicidal behavior in adolescents. Family communication is a protective factor that has seldom been studied in the specific problem of suicidal ideation in adolescent victims of traditional victimization and cyber-victimization. The objective of the present study was to use two different moderated mediation models to analyze the direct and indirect-mediating-effects of traditional victimization and cyber-victimization on suicidal ideation in adolescents, as well as the moderating role of family communication in the relationships between traditional victimization, cyber-victimization, and suicidal ideation. METHOD: 1007 adolescents (51.9% boys) aged 12-18 years participated. RESULTS: Significant direct and indirect effects of traditional victimization and cyber-victimization on suicidal ideation were confirmed. Family communication moderated the direct effects of cyber-victimization on suicidal ideation, but not the direct effects of traditional victimization on suicidal ideation. In addition, it moderated the relationship between traditional victimization and cyber-victimization. CONCLUSIONS: Family communication is a protective factor associated with decreased cyber-victimization in adolescents who suffer traditional victimization and reduced suicidal ideation in victims of cyber-victimization.

Cryogenic nano-imaging of second-order moiré superlattices.

Second-order superlattices form when moiré superlattices with similar periodicities interfere with each other, leading to larger superlattice periodicities. These crystalline structures are engineered using two-dimensional materials such as graphene and hexagonal boron nitride, and the specific alignment plays a crucial role in facilitating correlation-driven topological phases. Signatures of second-order superlattices have been identified in magnetotransport experiments; however, real-space visualization is still lacking. Here we reveal the second-order superlattice in magic-angle twisted bilayer graphene closely aligned with hexagonal boron nitride through electronic transport measurements and cryogenic nanoscale photovoltage measurements and evidenced by long-range periodic photovoltage modulations. Our results show that even minuscule strain and twist-angle variations as small as 0.01° can lead to drastic changes in the second-order superlattice structure. Our real-space observations, therefore, serve as a 'magnifying glass' for strain and twist angle and can elucidate the mechanisms responsible for the breaking of spatial symmetries in twisted bilayer graphene.

Design considerations for digital light processing bioprinters.

With the rapid development and popularization of additive manufacturing, different technologies, including, but not limited to, extrusion-, droplet-, and vat-photopolymerization-based fabrication techniques, have emerged that have allowed tremendous progress in three-dimensional (3D) printing in the past decades. Bioprinting, typically using living cells and/or biomaterials conformed by different printing modalities, has produced functional tissues. As a subclass of vat-photopolymerization bioprinting, digital light processing (DLP) uses digitally controlled photomasks to selectively solidify liquid photocurable bioinks to construct complex physical objects in a layer-by-layer manner. DLP bioprinting presents unique advantages, including short printing times, relatively low manufacturing costs, and decently high resolutions, allowing users to achieve significant progress in the bioprinting of tissue-like complex structures. Nevertheless, the need to accommodate different materials while bioprinting and improve the printing performance has driven the rapid progress in DLP bioprinters, which requires multiple pieces of knowledge ranging from optics, electronics, software, and materials beyond the biological aspects. This raises the need for a comprehensive review to recapitulate the most important considerations in the design and assembly of DLP bioprinters. This review begins with analyzing unique considerations and specific examples in the hardware, including the resin vat, optical system, and electronics. In the software, the workflow is analyzed, including the parameters to be considered for the control of the bioprinter and the voxelizing/slicing algorithm. In addition, we briefly discuss the material requirements for DLP bioprinting. Then, we provide a section with best practices and maintenance of a do-it-yourself DLP bioprinter. Finally, we highlight the future outlooks of the DLP technology and their critical role in directing the future of bioprinting. The state-of-the-art progress in DLP bioprinter in this review will provide a set of knowledge for innovative DLP bioprinter designs.

ginmappeR: an unified approach for integrating gene and protein identifiers across biological sequence databases.

Summary: The proliferation of biological sequence data, due to developments in molecular biology techniques, has led to the creation of numerous open access databases on gene and protein sequencing. However, the lack of direct equivalence between identifiers across these databases difficults data integration. To address this challenge, we introduce ginmappeR, an integrated R package facilitating the translation of gene and protein identifiers between databases. By providing a unified interface, ginmappeR streamlines the integration of diverse data sources into biological workflows, so it enhances efficiency and user experience. Availability and implementation: from Bioconductor: https://bioconductor.org/packages/ginmappeR.

Monitoring Fruit Growth and Development in Apricot (Prunus armeniaca L.) through Gene Expression Analysis.

The main objective of this study was to monitor apricot development and ripening through gene expression analysis of key candidate genes using the RT-qPCR technique. Eight apricot cultivars were selected to analyze phenological and genetic patterns from pre-ripening stages through to postharvest. In addition, 19 selected genes were analyzed in the contrasting cultivars 'Cebas Red' and 'Rojo Pasión' in different stages (two preharvest stages S1 and S2, one harvest stage S3, and two postharvest stages S4 and S5). This pool of genes included genes related to fruit growth and ripening, genes associated with fruit color, and genes linked to the fruit's nutraceutical aspects. Among the studied genes, Polygalacturonase (PG), Pectin methylesterase (PME), Aminocyclopropane-1-carboxylate synthase (ACS), and Myo-inositol-1-phosphate synthase (INO1) were directly related to fruit maturation and quality. Significant differential expression was observed between the cultivars, which correlated with variations in firmness, shelf life, and sensory characteristics of the apricots. 'Rojo Pasión' displayed high levels of PG, associated with rapid maturation and shorter postharvest shelf life, whereas 'Cebas Red' exhibited lower levels of this gene, resulting in greater firmness and extended shelf life. Genes CCD4, CRTZ, and ZDS, related to carotenoids, showed varied expression patterns during growth and postharvest stages, with higher levels in 'Rojo Pasión'. On the other hand, Sucrose synthase (SUSY) and Lipoxygenase (LOX2) were prominent during the postharvest and growth stages, respectively. Additionally, GDP-L-galactose phosphorylase (VTC2_5) was linked to better postharvest performance. This research provides valuable insights for future breeding initiatives aimed at enhancing the quality and sustainability of apricot cultivation.

The vast majority of somatic mutations in plants are layer-specific.

BACKGROUND: Plant meristems are structured organs consisting of distinct layers of stem cells, which differentiate into new plant tissue. Mutations in meristematic layers can propagate into large sectors of the plant. However, the characteristics of meristematic mutations remain unclear, limiting our understanding of the genetic basis of somaclonal phenotypic variation. RESULTS: Here, we analyse the frequency and distribution of somatic mutations in an apricot tree. We separately sequence the epidermis (developing from meristem layer 1) and the flesh (developing from meristem layer 2) of several fruits sampled across the entire tree. We find that most somatic mutations (> 90%) are specific to individual layers. Interestingly, layer 1 shows a higher mutation load than layer 2, implying different mutational dynamics between the layers. The distribution of somatic mutations follows the branching of the tree. This suggests that somatic mutations are propagated to developing branches through axillary meristems. In turn, this leads us to the unexpected observation that the genomes of layer 1 of distant branches are more similar to each other than to the genomes of layer 2 of the same branches. Finally, using single-cell RNA sequencing, we demonstrate that layer-specific mutations were only transcribed in the cells of the respective layers and can form the genetic basis of somaclonal phenotypic variation. CONCLUSIONS: Here, we analyse the frequency and distribution of somatic mutations with meristematic origin. Our observations on the layer specificity of somatic mutations outline how they are distributed, how they propagate, and how they can impact clonally propagated crops.

Systemic and targeted activation of Nrf2 reverses doxorubicin-induced cognitive impairments and sensorimotor deficits in mice.

While cancer survivorship has increased due to advances in treatments, chemotherapy often carries long-lived neurotoxic side effects which reduce quality of life. Commonly affected domains include memory, executive function, attention, processing speed and sensorimotor function, colloquially known as chemotherapy-induced cognitive impairment (CICI) or "chemobrain". Oxidative stress and neuroimmune signaling in the brain have been mechanistically linked to the deleterious effects of chemotherapy on cognition and sensorimotor function. With this in mind, we tested if activation of the master regulator of antioxidant response nuclear factor E2-related factor 2 (Nrf2) alleviates cognitive and sensorimotor impairments induced by doxorubicin. The FDA-approved systemic Nrf2 activator, diroximel fumarate (DRF) was used, along with our recently developed prodrug 1c which has the advantage of specifically releasing monomethyl fumarate at sites of oxidative stress. DRF and 1c both reversed doxorubicin-induced deficits in executive function, spatial and working memory, as well as decrements in fine motor coordination and grip strength, across both male and female mice. Both treatments reversed doxorubicin-induced loss of synaptic proteins and microglia phenotypic transition in the hippocampus. Doxorubicin-induced myelin damage in the corpus callosum was reversed by both Nrf2 activators. These results demonstrate the therapeutic potential of Nrf2 activators to reverse doxorubicin-induced cognitive impairments, motor incoordination, and associated structural and phenotypic changes in the brain. The localized release of monomethyl fumarate by 1c has the potential to diminish unwanted effects of fumarates while retaining efficacy.

Aromatic 1,4,2,3-Diazadiborole Featuring an Unsymmetrical B=B Entity: A Versatile Synthon for Unusual Boron Heterocycles.

The replacement of a CC unit with an isoelectronic BN unit in aromatic systems can give rise to molecules and materials with fascinating properties. We report here the synthesis, characterization, and reactivity of a 1,4,2,3-diazadiborole species, 2, featuring an unprecedented 6π-aromatic BN-heterocyclic moiety that is isoelectronic to cyclopentadienide (Cp-). Bearing an unsymmetrical B=B entity, 2 exhibits reactivity toward oxidants, protic reagents, electrophiles, and unsaturated substrates. This reactivity facilitates the synthesis of a variety of novel mono- and bicyclic organoboron derivatives through mechanisms including ring retention, cleavage/recombination, annulation, and expansion. These findings reveal innovative synthetic routes to BN-embedded aromatic compounds via desymmetrization, affording unique building blocks for synthetic chemistry.

Hospital Volume of Elective Abdominal Aortic Aneurysm Repair as a Predictor of Mortality After Ruptured Abdominal Aortic Aneurysm Repair.

OBJECTIVE: Registry data suggest that centralising abdominal aortic aneurysm (AAA) surgery decreases the mortality rate after AAA repair. However, the impact of higher elective volumes on ruptured AAA (rAAA) repair associated mortality rates remains uncertain. This study aimed to examine associations between intact AAA (iAAA) repair volume and post-operative rAAA death. METHODS: Using data from official national registries between 2015 - 2019, all iAAA and rAAA repairs were separately analysed across 10 public hospitals. The following were assessed: 30 day and 12 month mortality rate following open surgical repair (OSR) and endovascular aneurysm repair (EVAR). Associations between the 5 year hospital iAAA repair volumes (organised into tertiles) and rAAA associated mortality rate were analysed, regardless of treatment modality. Receiver operating characteristic (ROC) curves were generated to identify iAAA volume thresholds for decreasing the rAAA mortality rate. Subanalysis by treatment type was conducted. Threshold analysis was repeated with the Markov chain Monte Carlo (MCMC) procedure to confirm the findings. RESULTS: A total of 1 599 iAAAs (80.2% EVAR, 19.8% OSR) and 196 rAAAs (66.3% EVAR, 33.7% OSR) repairs were analysed. The median and interquartile range of the volume/hospital/year for all iAAA repairs were 39.2 (31.2, 47.4). The top volume iAAA tertile exhibited lower rAAA associated 30 day (odds ratio [OR] 0.374; p = .007) and 12 month (OR 0.264; p < .001) mortality rates. The ROC analysis revealed a threshold of 40 iAAA repairs/hospital/year (EVAR + OSR) for a reduced rAAA mortality rate. Middle volume hospitals for open iAAA repair had reduced 30 day (OR 0.267; p = .033) and 12 month (OR 0.223; p = .020) mortality rates, with a threshold of five OSR procedures/year. The MCMC procedure found similar thresholds. No significant association was found between elective EVAR volumes and ruptured EVAR mortality. CONCLUSION: Higher iAAA repair volumes correlated with a lower rAAA mortality rate, particularly for OSR. The recommended iAAA repair threshold is 40 procedures/year and five procedures/year for OSR. These findings support high elective volumes for improving the rAAA mortality rate, especially for OSR.

Using Principles of Digital Development for a Smartphone App to Support Data Collection in Patients With Acute Myocardial Infarction and Physical Activity Intolerance: Case Study.

BACKGROUND: Advances in health have highlighted the need to implement technologies as a fundamental part of the diagnosis, treatment, and recovery of patients at risk of or with health alterations. For this purpose, digital platforms have demonstrated their applicability in the identification of care needs. Nursing is a fundamental component in the care of patients with cardiovascular disorders and plays a crucial role in diagnosing human responses to these health conditions. Consequently, the validation of nursing diagnoses through ongoing research processes has become a necessity that can significantly impact both patients and health care professionals. OBJECTIVE: We aimed to describe the process of developing a mobile app to validate the nursing diagnosis "intolerance to physical activity" in patients with acute myocardial infarction. METHODS: We describe the development and pilot-testing of a mobile system to support data collection for validating the nursing diagnosis of activity intolerance. This was a descriptive study conducted with 11 adults (aged ≥18 years) who attended a health institution for highly complex needs with a suspected diagnosis of coronary syndrome between August and September 2019 in Floridablanca, Colombia. An app for the clinical validation of activity intolerance (North American Nursing Diagnosis Association [NANDA] code 00092) in patients with acute coronary syndrome was developed in two steps: (1) operationalization of the nursing diagnosis and (2) the app development process, which included an evaluation of the initial requirements, development and digitization of the forms, and a pilot test. The agreement level between the 2 evaluating nurses was evaluated with the κ index. RESULTS: We developed a form that included sociodemographic data, hospital admission data, medical history, current pharmacological treatment, and thrombolysis in myocardial infarction risk score (TIMI-RS) and GRACE (Global Registry of Acute Coronary Events) scores. To identify the defining characteristics, we included official guidelines, physiological measurements, and scales such as the Piper fatigue scale and Borg scale. Participants in the pilot test (n=11) had an average age of 63.2 (SD 4.0) years and were 82% (9/11) men; 18% (2/11) had incomplete primary schooling. The agreement between the evaluators was approximately 80% for most of the defining characteristics. The most prevalent characteristics were exercise discomfort (10/11, 91%), weakness (7/11, 64%), dyspnea (3/11, 27%), abnormal heart rate in response to exercise (2/10, 20%), electrocardiogram abnormalities (1/10, 9%), and abnormal blood pressure in response to activity (1/10, 10%). CONCLUSIONS: We developed a mobile app for validating the diagnosis of "activity intolerance." Its use will guarantee not only optimal data collection, minimizing errors to perform validation, but will also allow the identification of individual care needs.

Diverging cell wall strategies for drought adaptation in two maize inbreds with contrasting lodging resistance.

The plant cell wall is a plastic structure of variable composition that constitutes the first line of defence against environmental challenges. Lodging and drought are two stressful conditions that severely impact maize yield. In a previous work, we characterised the cell walls of two maize inbreds, EA2024 (susceptible) and B73 (resistant) to stalk lodging. Here, we show that drought induces distinct phenotypical, physiological, cell wall, and transcriptional changes in the two inbreds, with B73 exhibiting lower tolerance to this stress than EA2024. In control conditions, EA2024 stalks had higher levels of cellulose, uronic acids and p-coumarate than B73. However, upon drought EA2024 displayed increased levels of arabinose-enriched polymers, such as pectin-arabinans and arabinogalactan proteins, and a decreased lignin content. By contrast, B73 displayed a deeper rearrangement of cell walls upon drought, including modifications in lignin composition (increased S subunits and S/G ratio; decreased H subunits) and an increase of uronic acids. Drought induced more substantial changes in gene expression in B73 compared to EA2024, particularly in cell wall-related genes, that were modulated in an inbred-specific manner. Transcription factor enrichment assays unveiled inbred-specific regulatory networks coordinating cell wall genes expression. Altogether, these findings reveal that B73 and EA2024 inbreds, with opposite stalk-lodging phenotypes, undertake different cell wall modification strategies in response to drought. We propose that the specific cell wall composition conferring lodging resistance to B73, compromises its cell wall plasticity, and renders this inbred more susceptible to drought.

High-quality nanocavities through multimodal confinement of hyperbolic polaritons in hexagonal boron nitride.

Compressing light into nanocavities substantially enhances light-matter interactions, which has been a major driver for nanostructured materials research. However, extreme confinement generally comes at the cost of absorption and low resonator quality factors. Here we suggest an alternative optical multimodal confinement mechanism, unlocking the potential of hyperbolic phonon polaritons in isotopically pure hexagonal boron nitride. We produce deep-subwavelength cavities and demonstrate several orders of magnitude improvement in confinement, with estimated Purcell factors exceeding 108 and quality factors in the 50-480 range, values approaching the intrinsic quality factor of hexagonal boron nitride polaritons. Intriguingly, the quality factors we obtain exceed the maximum predicted by impedance-mismatch considerations, indicating that confinement is boosted by higher-order modes. We expect that our multimodal approach to nanoscale polariton manipulation will have far-reaching implications for ultrastrong light-matter interactions, mid-infrared nonlinear optics and nanoscale sensors.

Effect of a blend of cinnamaldehyde, eugenol, and Capsicum oleoresin on methane emission and lactation performance of Holstein-Friesian dairy cows.

This study aimed to investigate the effect of administering a standardized blend of cinnamaldehyde, eugenol, and Capsicum oleoresin (CEC) to lactating dairy cattle for 84 d (i.e., 12 wk) on enteric CH4 emission, feed intake, milk yield and composition, and body weight. The experiment involved 56 Holstein-Friesian dairy cows (145 ± 31.1 d in milk at the start of the trial; mean ± standard deviation) in a randomized complete block design. Cows were blocked in pairs according to parity, lactation stage, and current milk yield, and randomly allocated to 1 of the 2 dietary treatments: a diet including 54.5 mg of CEC/kg of DM or a control diet without CEC. Diets were provided as partial mixed rations in feed bins, which automatically recorded individual feed intake. Additional concentrate was fed in the GreenFeed system that was used to measure emissions of CO2, CH4, and H2. Feeding CEC decreased CH4 yield (g/kg DMI) by on average 3.4% over the complete 12-wk period and by on average 3.9% from 6 wk after the start of supplementation onward. Feeding CEC simultaneously increased feed intake and body weight, and tended to increase milk protein content, whereas no negative responses were observed. These results must be further investigated and confirmed in longer-term in vivo experiments.

Methane prediction equations including genera of rumen bacteria as predictor variables improve prediction accuracy.

Methane (CH4) emissions from ruminants are of a significant environmental concern, necessitating accurate prediction for emission inventories. Existing models rely solely on dietary and host animal-related data, ignoring the predicting power of rumen microbiota, the source of CH4. To address this limitation, we developed novel CH4 prediction models incorporating rumen microbes as predictors, alongside animal- and feed-related predictors using four statistical/machine learning (ML) methods. These include random forest combined with boosting (RF-B), least absolute shrinkage and selection operator (LASSO), generalized linear mixed model with LASSO (glmmLasso), and smoothly clipped absolute deviation (SCAD) implemented on linear mixed models. With a sheep dataset (218 observations) of both animal data and rumen microbiota data (relative sequence abundance of 330 genera of rumen bacteria, archaea, protozoa, and fungi), we developed linear mixed models to predict CH4 production (g CH4/animal·d, ANIM-B models) and CH4 yield (g CH4/kg of dry matter intake, DMI-B models). We also developed models solely based on animal-related data. Prediction performance was evaluated 200 times with random data splits, while fitting performance was assessed without data splitting. The inclusion of microbial predictors improved the models, as indicated by decreased root mean square prediction error (RMSPE) and mean absolute error (MAE), and increased Lin's concordance correlation coefficient (CCC). Both glmmLasso and SCAD reduced the Akaike information criterion (AIC) and Bayesian information criterion (BIC) for both the ANIM-B and the DMI-B models, while the other two ML methods had mixed outcomes. By balancing prediction performance and fitting performance, we obtained one ANIM-B model (containing 10 genera of bacteria and 3 animal data) fitted using glmmLasso and one DMI-B model (5 genera of bacteria and 1 animal datum) fitted using SCAD. This study highlights the importance of incorporating rumen microbiota data in CH4 prediction models to enhance accuracy and robustness. Additionally, ML methods facilitate the selection of microbial predictors from high-dimensional metataxonomic data of the rumen microbiota without overfitting. Moreover, the identified microbial predictors can serve as biomarkers of CH4 emissions from sheep, providing valuable insights for future research and mitigation strategies.

Obtention and Study of Polyurethane-Based Active Packaging with Curcumin and/or Chitosan Additives for Fruits and Vegetables-Part I: Analysis of Morphological, Mechanical, Barrier, and Migration Properties.

Several polyurethane-formulated films with curcumin and/or chitosan additives for food packaging have been previously obtained. The study examines the effect of the additives on the film's morphological, mechanical, barrier, and migration properties. Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), water contact angle, thermogravimetric and differential thermal analysis (TGA and DTGA), differential scanning calorimetry (DSC), dynamic mechanical thermal analysis (DMTA), oxygen transmission rate (OTR), water vapor transmission rate (WVTR), and the overall and specific migration tests were conducted. The results show that the presence of chitosan significantly increased the overall migration and mechanical properties, such as the elongation at break, tensile strength, and Young's modulus of most polyurethane formulations, while curcumin had a minor influence on the mechanical performance. Based on the results, formulations with curcumin but without chitosan are suitable for food packaging.

Rumen microbial degradation of bromoform from red seaweed (Asparagopsis taxiformis) and the impact on rumen fermentation and methanogenic archaea.

BACKGROUND: The red macroalgae Asparagopsis is an effective methanogenesis inhibitor due to the presence of halogenated methane (CH4) analogues, primarily bromoform (CHBr3). This study aimed to investigate the degradation process of CHBr3 from A. taxiformis in the rumen and whether this process is diet-dependent. An in vitro batch culture system was used according to a 2 × 2 factorial design, assessing two A. taxiformis inclusion rates [0 (CTL) and 2% DM diet (AT)] and two diets [high-concentrate (HC) and high-forage diet (HF)]. Incubations lasted for 72 h and samples of headspace and fermentation liquid were taken at 0, 0.5, 1, 3, 6, 8, 12, 16, 24, 48 and 72 h to assess the pattern of degradation of CHBr3 into dibromomethane (CH2Br2) and fermentation parameters. Additionally, an in vitro experiment with pure cultures of seven methanogens strains (Methanobrevibacter smithii, Methanobrevibacter ruminantium, Methanosphaera stadtmanae, Methanosarcina barkeri, Methanobrevibacter millerae, Methanothermobacter wolfei and Methanobacterium mobile) was conducted to test the effects of increasing concentrations of CHBr3 (0.4, 2, 10 and 50 µmol/L). RESULTS: The addition of AT significantly decreased CH4 production (P = 0.002) and the acetate:propionate ratio (P = 0.003) during a 72-h incubation. The concentrations of CHBr3 showed a rapid decrease with nearly 90% degraded within the first 3 h of incubation. On the contrary, CH2Br2 concentration quickly increased during the first 6 h and then gradually decreased towards the end of the incubation. Neither CHBr3 degradation nor CH2Br2 synthesis were affected by the type of diet used as substrate, suggesting that the fermentation rate is not a driving factor involved in CHBr3 degradation. The in vitro culture of methanogens showed a dose-response effect of CHBr3 by inhibiting the growth of M. smithii, M. ruminantium, M. stadtmanae, M. barkeri, M. millerae, M. wolfei, and M. mobile. CONCLUSIONS: The present work demonstrated that CHBr3 from A. taxiformis is quickly degraded to CH2Br2 in the rumen and that the fermentation rate promoted by different diets is not a driving factor involved in CHBr3 degradation.

The puzzle of plant hybridisation: a high propensity to hybridise but few hybrid zones reported.

An interesting conundrum was recently revealed by R. Abbott when he found that the number of hybrid zones reported in the literature for plants is very low, given the propensity of plants to hybridise. In another literature survey on hybrid zones performed over the period 1970-2022, we found that the number of hybrid zones reported for vertebrates was 2.3 times greater than that reported for vascular plants, even though there are about six times more vascular plant species than vertebrates. Looking at the number of papers reporting hybrid zones, there are 4.9 times more on vertebrates than on vascular plants. These figures support the relevance of this conundrum. In this paper we aim to shed light on this question by providing a structured discussion of the causes that may underlie this conundrum. We propose six non-mutually exclusive factors, namely lack or deficit of spatial structure, lack or deficit of genetic structure, effects of hybridisation between non-closely related species, lability of plant hybrid zones over time, botanists' perception of hybridisation, and deficit of population genetic data. There does not appear to be a single factor that explains our puzzle, which applies to all cases of plants where hybridisation is detected but no hybrid zone is reported. It is argued that some plant features suggest that the puzzle is not, at least entirely, due to insufficient knowledge of the specific cases, a hypothesis that should be addressed with a wider range of empirical data across different taxonomic groups.

Experimental signatures of the transition from acoustic plasmon to electronic sound in graphene.

Fermi liquids respond differently to perturbations depending on whether their frequency is higher (collisionless regime) or lower (hydrodynamic regime) than the interparticle collision rate. This results in a different phase velocity between the collisionless zero sound and the hydrodynamic first sound. We performed terahertz photocurrent nanoscopy measurements on graphene devices, with a metallic gate close to the graphene layer, to probe the dispersion of propagating acoustic plasmons, the counterpart of sound modes in electronic Fermi liquids. We report the observation of a change in the plasmon phase velocity when the excitation frequency approaches the electron-electron collision rate that is compatible with the transition between the zero and the first sound mode.

Multi-omics in vitro study of the salivary modulation of the goat rumen microbiome.

Ruminants are able to produce large quantities of saliva which enter into the rumen and salivary components exert different physiological functions. Although previous research has indicated that salivary immunoglobulins can partially modulate the rumen microbial activity, the role of the salivary components other than ions on the rumen microbial ecosystem has not been thoroughly investigated in ruminants. To investigate this modulatory activity, a total of 16 semi-continuous in vitro cultures with oats hay and concentrate were used to incubate rumen fluid from four donor goats with autoclaved saliva (AUT) as negative control, saliva from the same rumen fluid donor (OWN) as positive control, and either goat (GOAT) or sheep (SHEEP) saliva as experimental interventions. Fermentation was monitored throughout 7 days of incubation and the microbiome and metabolome were analysed at the end of this incubation by Next-Generation sequencing and liquid chromatography coupled with mass spectrometry, respectively. Characterisation of the proteome and metabolome of the different salivas used for the incubation showed a high inter-animal variability in terms of metabolites and proteins, including immunoglobulins. Incubation with AUT saliva promoted lower fermentative activity in terms of gas production (-9.4%) and highly divergent prokaryotic community in comparison with other treatments (OWN, GOAT and SHEEP) suggesting a modulatory effect derived from the presence of bioactive salivary components. Microbial alpha-diversity at amplicon sequence variant (ASV) level was unaffected by treatment. However, some differences were found in the microbial communities across treatments, which were mostly caused by a greater abundance of Proteobacteria and Rikenellacea in the AUT treatment and lower of Prevotellaceae. These bacteria, which are key in the rumen metabolism, had greater abundances in GOAT and SHEEP treatments. Incubation with GOAT saliva led to a lower protozoal concentration and propionate molar proportion indicating a capacity to modulate the rumen microbial ecosystem. The metabolomics analysis showed that the AUT samples were clustered apart from the rest indicating different metabolic pathways were promoted in this treatment. These results suggest that specific salivary components contribute to host-associated role in selecting the rumen commensal microbiota and its activity. These findings could open the possibility of developing new strategies to modulate the saliva composition as a way to manipulate the rumen function and activity.