Long-term Stability Research Articles

Tuning Adsorbate-Mediated Strong Metal-Support Interaction by Oxygen Vacancy: A Case Study in Ru/TiO2.

The adsorbate-mediated strong metal-support interaction (A-SMSI) offers a reversible means of altering the selectivity of supported metal catalysts, thereby providing a powerful tool for facile modulation of catalytic performance. However, the fundamental understanding of A-SMSI remains inadequate and methods for tuning A-SMSI are still in their nascent stages, impeding its stabilization under reaction conditions. Here, we report that the initial concentration of oxygen vacancy in oxide supports plays a key role in tuning the A-SMSI between Ru nanoparticles and defected titania (TiO2-x). Based on this new understanding, we demonstrate the in situ formation of A-SMSI under reaction conditions, obviating the typically required CO2-rich pretreatment. The as-formed A-SMSI layer exhibits remarkable stability at various temperatures, enabling excellent activity, selectivity and long-term stability in catalyzing the reverse water gas-shift reaction. This study deepens the understanding of the A-SMSI and the ability to stabilize A-SMSI under reaction conditions represents a key step for practical catalytic applications.

Synthesis of platinum-nickel nanoparticles supported by carbon and titanium oxide structures for efficient and enhanced formic acid oxidation

In this study, Platinum Nickel (PtNi) nanoparticles was synthesized using the chemical reduction method and functionalized multi-walled carbon nanotube (f-MWCNT) was synthesized by handling multi-walled carbon nanotube (MWCNT) with weak acid using the arc discharge method. To be evaluated in formic acid oxidation, f-MWCNT supported by PtNi (PtNi@f-MWCNT) and titanium oxide (TiO2) supported by PtNi (PtNi@TiO2) catalysts were synthesized using chemical reduction method. The comparison of PtNi, PtNi@f-MWCNT, and PtNi@TiO2 catalysts obtained in the study for formic acid oxidation is presented and their characterizations were carried out by X-ray Diffraction (XRD), Transmission Electron Microscope (TEM), and Fourier Transform Infrared Spectrometer (FTIR). According to TEM results; PtNi, PtNi@f-MWCNT, and PtNi@TiO2 particle sizes were found to be 12.00 nm, 7.37 nm, and 5.38 nm, respectively. According to the CV results obtained for formic acid oxidation, the anodic peak peaks for PtNi, PtNi@f-MWCNT, and PtNi@TiO2 were 61.20 mA.cm−2, 80.17 mA.cm−2 and 65.07 mA.cm−2, respectively. These results showed that the addition of f-MWCNT and TiO2 support exhibited 1.30 and 1.06 times higher electrocatalytic activity for formic acid oxidation and higher resistance to CO poisoning with If/Ib ratios of 0.97 and 1.48, respectively. With the long-term stability tests obtained, it was observed that the f-MWCNT-supported catalyst showed approximately 9 times more current at the end of 5000 s and provided faster charge transfer with EIS. These findings demonstrated that a more cost-effective catalyst with high electrocatalytic activity was synthesized by obtaining f-MWCNTs from MWCNTs using the arc discharge method. It has also been revealed that TiO2 and f-MWCNT supports exhibit very high potential for fuel cell applications.

Nest-Scheme RuIrLa Nanocrystals by NP-to-NP Oriented Assembly: Coherent Strain Fields-Driven Band Structure Splitting for Efficient Acidic Water Oxidation.

Atomic substructure engineering provides new opportunities for the designing newly and efficient catalysts with diverse atom ensembles, trimmed electron bands, and way-out coordination environments, creating unique contributing to concertedly catalyze water oxidation, which is of great significance for proton exchange membrane water electrolysis (PEMWE). Herein, nest-scheme RuIrLa nanocrystals with dense coherent interfaces as built-in substructures are firstly fabricated by using commercial ZnO particles as acid-removable templates, through a La-stabilized coherent epitaxial growth of nanoparticles (NPs). The obtained nests exhibit a low overpotential of 198mV at 10mA cm-2, and the RuIrLa||Pt/C module equipped in PEMWE operates stably at a cell voltage potential of 1.69V at 100mA cm-2 in 0.5M H2SO4 for 55h, which is far beyond the current IrO2||Pt/C. Within the nests, the position at the interface shows high tensile/compressive strain, significantly reducing the OER activation energy. More importantly, the La termination-stabilized coherent interfaces within the nests creates a unique self-healing process for the outstanding long-term stability. This work provides a promising substructure engineering to develop efficient catalysts with abundant substructures, such as coherent interfaces, dislocations, or grain boundaries, thereby realizing concerted improvement of activity and durability toward water oxidation.

Energy-Efficient Co-production of Benzoquinone and H2 Using Waste Phenol in a Hybrid Alkali/Acid Flow Cell.

In both the manufacturing and chemical industries, benzoquinone is a crucial chemical product. A perfect and economical method for making benzoquinone is the electrochemical oxidation of phenol, thanks to the traditional thermal catalytic oxidation of phenol process requires high cost, serious pollution and harsh reaction conditions. Here, a unique heterostructure electrocatalyst on nickel foam (NF) consisting of nickel sulfide and nickel oxide (Ni9S8-Ni15O16/NF) was produced, and this catalyst exhibited a low overpotential (1.35 V vs. RHE) and prominent selectivity (99 %) for electrochemical phenol oxidation reaction (EOP). Ni9S8-Ni15O16/NF is beneficial for lowering the reaction energy barrier and boosting reactivity in the EOP process according to density functional theory (DFT) calculations. Additionally, an alkali/acid hybrid flow cell was successfully established by connecting Ni9S8-Ni15O16/NF and commercial RuIr/Ti in series to catalyze phenol oxidation in an alkaline medium and hydrogen evolution in an acid medium, respectively. A cell voltage of only 0.60 V was applied to produce a current density of 10 mA cm-2. Meanwhile, the system continued to operate at 0.90 V for 12 days, showing remarkable long-term stability. The unique configuration of the acid-base hybrid flow cell electrolyzer provides valuable guidance for the efficient and environmentally friendly electrooxidation of phenol to benzoquinone.

Long-term climatic stability drives accumulation and maintenance of divergent freshwater fish lineages in a temperate biodiversity hotspot.

Anthropogenic climate change is forecast to drive regional climate disruption and instability across the globe. These impacts are likely to be exacerbated within biodiversity hotspots, both due to the greater potential for species loss but also to the possibility that endemic lineages might not have experienced significant climatic variation in the past, limiting their evolutionary potential to respond to rapid climate change. We assessed the role of climatic stability on the accumulation and persistence of lineages in an obligate freshwater fish group endemic to the southwest Western Australia (SWWA) biodiversity hotspot. Using 19,426 genomic (ddRAD-seq) markers and species distribution modelling, we explored the phylogeographic history of western (Nannoperca vittata) and little (Nannoperca pygmaea) pygmy perches, assessing population divergence and phylogenetic relationships, delimiting species and estimating changes in species distributions from the Pliocene to 2100. We identified two deep phylogroups comprising three divergent clusters, which showed no historical connectivity since the Pliocene. We conservatively suggest these represent three isolated species with additional intraspecific structure within one widespread species. All lineages showed long-term patterns of isolation and persistence owing to climatic stability but with significant range contractions likely under future climate change. Our results highlighted the role of climatic stability in allowing the persistence of isolated lineages in the SWWA. This biodiversity hotspot is under compounding threat from ongoing climate change and habitat modification, which may further threaten previously undetected cryptic diversity across the region.

Comprehensive calibration and laboratory validation of a micro electromechanical system sensor-based flexible inclinometer

Abstract Real-time monitoring of slopes, tunnels, and dams is important for ensuring the long-term stability and reliability of such structures. Despite the successes of current technologies in many applications, a gap still exists in certain areas such as precision in steep slopes and complex soil conditions. This study has designed a flexible inclinometer based on an array of Micro Electromechanical System (MEMS) sensors to enhance the accuracy and flexibility of existing monitoring techniques. The inclination angle of each flexible inclinometer measurement unit was measured to monitor the horizontal or vertical displacement of the target structural body. We used the Levenberg–Marquardt (LM) algorithm for optimizing the MEMS sensors based calibration and designed multiple experiments to test the accuracy of the proposed method. Experimental results show that the calibrated flexible inclinometer measurement unit has an inclination angle of less than 0.04° and the accuracy of the flexible inclinometer lies within ±0.4 mm in the horizontal attitude and 1.6 mm in the vertical attitude. Our research has developed a novel tool for geotechnical engineering monitoring that can aid in increasing the precision of real-time assessment and prediction of structural stability.

Does Screw Number of Zero-profile Implants in Fusion Segment Influence Intervertebral Stability?

The unclear clinical outcomes of two different zero-profile implants with different number of screws in hybrid surgery restricts the choice of patient-specific implants. This study aims to compare two different implants on its postoperative subsidence, motion stabilization and clinical outcomes. It also provides references to the most reasonable implant choice in fusion surgery. This was a retrospective study. From February 2014 to March 2022, 173 patients who underwent hybrid surgery were included. Among them, 122 received surgery with a four screw implant, while 51 received a two screw implant. We analyzed the significance of patient-specific factors, radiographic factors and clinical outcomes. The Wilcoxon rank sum test, t tests/analysis of variance (ANOVA) test and stepwise multivariate logistic regression were adopted for statistical analysis. No statistically significant difference was observed between the two screw and four screw groups in terms of immediate, middle, and long-term stability and fusion rate (p > 0.05). However, the two screws group had higher FSU height subsidence at 3, 6, and 12 months postoperatively and higher rates of significant subsidence at three and 6 months postoperatively (p < 0.05). Both groups showed significant clinical improvements at the final follow-up. Two screw and four screw implants provide comparable stability, fusion rates and clinical outcomes. However, the two screw implant was inferior to the four screw implant in subsidence prevention. Therefore, the two-screw implant is non-inferior to the four-screw implant in most patients. It can be used as the priority choice in the fusion segment by its easy manageability. However, the patients with a high risk of subsidence such as multilevel surgery, the elderly, lower BMD, bad cervical alignment should receive a four screw implant rather than a two screw implant.

RESEARCH ON THE ATTITUDE OF YOUNG PEOPLE REGARDING THE ATTRACTIVENESS OF AGRICULTURE: A CASE STUDY OF SERBIA

Agriculture plays a crucial role in any economy. However, agricultural work is often regarded as unpopular, dirty and lacking prestige. As a consequence, young people frequently migrate from rural to urban areas in search of alternative activities. This study addresses the challenge of integrating youth into the agricultural workforce. The objective is to assess the reasons behind youth’s (un) willingness to engage in agricultural work, using Serbia as a case study. Data were collected through a questionnaire and 308 responses were analyzed with the help of Binary Logistic Regression. The findings indicate that the attitude of young individuals to engage in agricultural work is significantly shaped by area of residence, family involvement, ownership of rural property, the economic viability of the agricultural sector and concerns about long-term employment stability. A few positive and negative stereotypes were also identified. The findings underscore the imperative to attract young people to work in agriculture.

10-Year Heterogeneity of Minimal Important Change and Patient Acceptable Symptom State After Lumbar Fusions.

Cohort study. To evaluate heterogeneity (fluctuation) in minimal important change (MIC) and patient acceptable symptom state (PASS) for patient-reported outcomes (PROMs) through 10 years after lumbar fusion. PROMs have become key determinants in spine surgery outcomes studies. MIC and PASS were established to aid PROM interpretations. However, their long-term stability has not yet been reported. A consecutive series of elective lumbar fusions were followed-up using the Oswestry Disability Index (ODI) and Visual Analogue Scale (VAS) for pain. Improvement was rated by a 4-point Likert scale into "improved" or "non-improved". Satisfaction-to-treatment was rated by the patients' willingness to undergo surgery again. Receiver operating characteristics (ROC) curve analysis estimated MIC (95% confidence interval, CI) as the PROM change that best predicted improvement at distinct time-points. PASS (CI) was estimated as the lowest PROM score at which the patients were still satisfied. Heterogeneity across thresholds was evaluated using the DeLong algorithm. MIC for ODI represented heterogeneity across 10-years, ranging from -21 (-24 to -16) at 2-years to -8 (-7 to -4) at 5-years, P <0.001. The areas under the ROC curves (AUCs) (0.79-0.85) indicated acceptable to excellent discrimination. Heterogeneity was not significant in the MICs for the pain scores. At 1-year, MIC for back pain was -24 (-38 to -15), AUC 0.77, and for leg pain it was -26 (-44 to -8), AUC 0.78. No significant heterogeneity was observed in 10-year PASS scores. At 1-year, PASS for ODI was 22 (15 to 29), AUC 0.85. Similarly, 1-year PASS for back pain was 38 (20 to 56), AUC 0.81, and for leg pain it was 49 (26 to 72), AUC 0.81. MIC for ODI fluctuated over 10-years after lumbar fusions. PASS values for all PROMs seemed most stable over time. Caution is needed when generic MIC values are used in long-term studies. Therapeutic Level III.

Mechanistic insight into the Janus Green B on electrochemical roughening layer of copper foil

This study explores the impact of the electroplating additive JGB the surface characteristics and peel strength of electrolytic copper foils used in printed circuit boards. Utilizing Scanning Electron Microscopy and Atomic Force Microscopy, we found that optimal JGB concentrations enhance the morphology and roughness of the copper foil roughening layer while maintaining high peel strength. The ideal concentration of 3 mg/L achieved an average roughness of 0.953 µm and a peel strength of 0.946 N/mm. JGB's effectiveness in inhibiting copper deposition was confirmed through cyclic voltammetry, linear sweep voltammetry, and electrochemical impedance spectroscopy. Density Functional Theory calculations and in situ infrared spectroscopy elucidated JGB's adsorption and coordination actions, which have a synergistic effect on its inhibitory performance. Further investigations with molecular dynamics simulations and finite element analysis demonstrated JGB's preferential adsorption in areas of high electric field intensity, effectively controlling the copper grain morphology in the roughening layer. This research highlights the potential of dye-type additives in improving copper foil roughening for printed circuit boards applications. Future research should explore the long-term stability and environmental impact of JGB in industrial applications, while investigating other dye-type additives may further optimize the roughening process to meet diverse printed circuit boards manufacturing needs.

Zn doped CeO2 supporting Ni–Pt catalysts toward robust hydrogen generation from hydrous hydrazine

Ni-based bimetallic catalysts with noble metals exhibit high activity and selectivity for hydrogen generation from hydrazine monohydrate. However, their poor service durability remains a critical challenge. This study investigated the use of Zn-doped CeO2 as a support for Ni–Pt catalysts to improve their long-term stability. A series of Ni–Pt/Zn-doped-CeO2 catalysts were prepared via a simple co-precipitation and reduction method. Compared to the pristine Ni50Pt50/CeO2 catalyst, the Zn doping can improve the stability of CeO2 support in the alkaline condition, and the X-ray photoelectron spectroscopy (XPS) analysis clearly indicates that Zn doping leads to a negative shift in the binding energy of connected Ni and thus enhances the stability of the electronic structure in the catalysts. The findings in this work suggest that Zn-modified CeO2 supporting Ni–Pt catalyst offer a promising approach to achieving a better balance between activity and durability for hydrogen generation catalysts.

Design an in-situ anti-bacterial structure of nanofiltration membrane with a novel bisimidazoline aqueous monomer

Bio-fouling is a key issue for the nanofiltration operation. In this study, 1, 2-bis (N-aminoethyl imidazoline) ethane (BAIE) firstly was used as a novel bisimidazoline aqueous monomer to prepare the anti-bacterial nanofiltration (NF) membranes. A novel nanofiltration (BAIE-TMC NF) membrane with in-situ anti-bacterial structure and anti-fouling property was fabricated via interfacial polymerization (IP) with trimesoyl chloride (TMC), basing on a polyethersulfone (PES) substrate. Protonated imidazole endowed the surface of BAIE-TMC NF membrane with weak electronegativity, and its salt rejection sequence was MgSO4 > Na2SO4 > MgCl2 > NaCl > LiCl. Meantime, the BAIE-TMC NF membrane with 0.5 wt% BAIE (M-0.5) exhibited a high rejection for bivalent ions, with a high MgSO4 rejection (94.7 %). Notably, BAIE-TMC NF membrane containing an in-situ anti-bacterial imidazole structure showed significant anti-fouling and anti-bacterial properties. After BSA or HA filtration process, the flux recovery rates of all BAIE-TMC NF membranes were higher than 95 %, and M-0.5 exhibited high inhibition performance against Escherichia coli (98.5 %) and Staphylococcus aureus (98.4 %). Furthermore, M-0.5 exhibited excellent long-term separation stability during the three weeks separation experiment. BAIE can serve as an effective aqueous monomer for fabricating in-situ anti-bacterial and anti-fouling NF membrane to achieve the rejection of organic pollutant and bivalent ions.

In Situ Phase Separation-Induced Self-Healing Catalyst for Efficient Direct Seawater Electrolysis.

Direct seawater electrolysis technology for sustainable hydrogen production has garnered significant attention, owing to its abundant resource supply and economic potential. However, the complex composition and high chloride concentration of seawater have hindered its practical implementation. In this study, we report an in situ-synthesized dual-phase electrocatalyst (HPS-NiMo), comprising an amorphous phosphide protective outer phase and a crystalline alloy inner phase with supplementary sulfur active sites, to improve the kinetics of direct seawater electrolysis. The HPS-NiMo exhibits long-term stability, remaining stable for periods exceeding 120 h at 200 mA cm-2; moreover, it lowers the required operating voltage to ∼1.8 V in natural seawater. The chlorine chemistry, corrosion during direct natural seawater electrolysis, and mechanism behind the high-performing catalysts are discussed. We also investigated the possibility of recovering the anode precipitates, which inevitably occurs during seawater electrolysis.

Upcycled Graphene Oxide Nanosheets for Reversible Room Temperature NO2 Gas Sensor

Graphene oxide (GO) nanosheets, as one of the most studied graphene derivatives, have demonstrated an intrinsically strong physisorption-based gas–matter behavior, owing to its enhanced volume–surface ratio and abundant surface functional groups. The exploration of efficient and cost-effective synthesis methods for GO is an ongoing task. In this work, we explored a novel approach to upcycle inexpensive polyethylene terephthalate (PET) plastic waste into high-quality GO using a combination of chemical and thermal treatments based on a montmorillonite template. The obtained material had a nanosheet morphology with a lateral dimension of around ~2 µm and a thickness of ~3 nm. In addition, the GO nanosheets were found to be a p-type semiconductor with a bandgap of 2.41 eV and was subsequently realized as a gas sensor. As a result, the GO sensor exhibited a fully reversible sensing response towards ultra-low-concentration NO2 gas with a limit of detection of ~1.43 ppb, without the implementation of an external excitation stimulus including elevating the operating temperature or bias voltages. When given a thorough test, the sensor maintained an impressive long-term stability and repeatability with little performance degradation after 5 days of experiments. The response factor was estimated to be ~11% when exposed to 1026 ppb NO2, which is at least one order of magnitude higher than that of other commonly seen gas species including CH4, H2, and CO2.

Reaction Center Shifting in Partially Fluorinated Electrolytes for Robust Lithium Metal Battery.

The strategic formulation of a compatible electrolyte plays a pivotal role in extending the longevity of lithium-metal batteries (LMBs). Here, we present findings on a partially fluorinated electrolyte distinguished by a subdued solvation affinity towards Li+ ions and a concentrated anion presence within the primary solvation layer. This distinctive solvation arrangement redirects the focal points of reactions from solvent molecules to anions, facilitating the predominant involvement of anions in the creation of a LiF-enriched solid-electrolyte interphase (SEI). Electrochemical assessments showcase effective Li+ transport kinetics, diminished overpotential polarization for Li nucleation, and prolonged cycling durability in Li||Li cells employing the partially fluorinated electrolyte. When tested in Li||NCM811 cells, the designed electrolyte delivers a capacity retention of 89.30% and exhibits a high average Coulombic efficiency of 99.80% over 100 cycles with a charge-potential cut-off of 4.6 V vs. Li/Li+ under the current density of 0.4 C. Furthermore, even at a current density of 1C, the cells maintain 81.90% capacity retention and a high average Coulombic efficiency of 99.40% after 180 cycles. This work underscores the significance of weak-solvation interaction in partially fluorinated electrolytes and highlights the crucial role of solvent structure in enabling the long-term stability and high-energy density of LMBs.

Single-atom iodine anchored layered graphitic carbon nitride: Dual functional Electrocatalyst for acetaminophen detection and oxygen evolution reaction

Developing highly effective bifunctional electrocatalysts for acetaminophen (ACP) detection and oxygen evolution reaction (OER) is significant and challenging. Thermal decomposition methods were used to create a high-radius and high electronegative iodine doped porous graphitic carbon nitride (IO-gCN) bifunctional electrocatalyst in here. The synergistic effect of pores nature, active sites and nanosheet-like structure, IO-gCN exhibit better ACP detection and OER activity. Under optimized conditions, IO-gCN detection limits (LOD) for ACP is 4.6 nM with a linear range of 0.2–80 μM and sensitivity is 3.234 μA μM−1 cm−2. The proposed nanosheets decorated disposable screen-printed carbon electrode (SPCE) also applied real samples (tap water and human urine sample) to obtained better recovery results. The electrochemical linear sweep voltammetry (LSV) exhibited a lower over potential (270 mV) and small Tafel slope value (144 mV/dec) at 10 mA/cm2 for IO-2 (2 wt% doped gCN) nanosheets under alkaline medium (1 M KOH). Additionally, the chronoamperometry (CA) test and the cyclic voltammetry 3000th cycle test both produced results for long-term stability and hybrid stability. This study offers a straightforward and esoteric method for creating bifunctional electrocatalysts that are free of metal.

Unlocking the Potential: Atomically Thin 2D Fluoritene from Exfoliated Fluorite Ore and Its Electrochemical Activity.

Fluorite mineral holds significant importance because of its optoelectronic properties and wide range of applications. Here, we report the successful exfoliation of bulk fluorite ore (calcium fluoride, CaF2) crystals into atomically thin two-dimensional fluoritene (2D CaF2) using a highly scalable liquid-phase exfoliation method. The microscopic and spectroscopy characterizations show the formation of (111) plane-oriented 2D CaF2 sheets with exfoliation-induced material strain due to bond breaking, leading to the changes in lattice parameter. Its potential role in electrocatalysis is further explored for deeper insight, and a probable mechanism is also discussed. The 2D CaF2 with long-term stability shows overpotential values of 670 and 770 mV vs RHE for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER), respectively, at 10 mA cm-2. Computational simulations demonstrate the unique "direct-indirect" band gap switching with odd and even numbers of layers. Current work offers new avenues for exploring the structural and electrochemical properties of 2D CaF2 and its potential applicability.

Biomaterial Improves the Stability of Perovskite Solar Cells by Passivating Defects and Inhibiting Ion Migration.

With the rapid improvement of power conversion efficiency (PCE), perovskite solar cells (PSCs) have broad application prospects and their industrialization will be the next step. Nevertheless, the performance and long-term stability of the devices are limited by the defect-induced nonradiative recombination centers and ions' migration inside the perovskite films. Here, usnic acid (UA), an easy-to-obtain and efficient natural biomaterial with a hydroxyl functional group (-OH) and four carbonyl groups (-C═O) was added to MAPbI3 perovskite precursor to regulate the crystallization process by slowing the crystallization rate, thereby expanding the crystal size and preparing perovskite films with low defect density. In addition, UA anchors the uncoordinated Pb2+ and suppresses the migration of I-ions, which enhances the stability of the perovskite film. Consequently, an impressive PCE exceeding 20% was achieved for inverted structure MAPbI3-based PSCs. More impressively, the optimized PSCs maintained 78% of the initial PCE under air with high humidity (RH ≈ 65%, 25-30 °C) for 1000 h. UA can be extracted from the plant, usnea, making it inexpensive and easy to obtain. Our work demonstrates the application of the plant material in PSCs and their industrialization, which is significant nowadays.

The CARMENES search for exoplanets around M dwarfs. Revisiting the GJ 581 multi-planetary system with new Doppler measurements from CARMENES, HARPS, and HIRES

GJ\,581 is a nearby M dwarf known to host a packed multiple planet system composed of two super-Earths and a Neptune-mass planet. We present new orbital analyses of the GJ\,581 system, utilizing recent radial velocity (RV) data obtained from the CARMENES spectrograph combined with newly reprocessed archival data from the HARPS and HIRES spectrographs. Our aim was to analyze the post-discovery spectroscopic data of GJ\,581, which were obtained with CARMENES. In addition, we used publicly available HIRES and HARPS spectroscopic data to seek evidence of the known and disputed exoplanets in this system. We aimed to investigate the stellar activity of GJ\,581 and update the planetary system's orbital parameters using state-of-the-art numerical models and techniques. We performed a periodogram analysis of the available precise CARMENES, HIRES, and HARPS RVs and of stellar activity indicators. We conducted detailed orbital analyses by testing various orbital configurations consistent with the RV data. We studied the posterior probability distribution of the parameters fit to the data and we explored the long-term stability and overall orbital dynamics of the GJ\,581 system. We refined the orbital parameters of the GJ\,581 system using the most precise and complete set of Doppler data available. Consistent with the existing literature, our analysis confirms that the system is unequivocally composed of only three planets detectable in the present data, dismissing the putative planet GJ\,581\,d as an artifact of stellar activity. Our N-body fit reveals that the system's inclination is $i = $\,deg, which implies that the planets could be up to 30&lt;!PCT!&gt; more massive than their previously reported minimum masses. Furthermore, we report that the GJ\,581 system exhibits long-term stability, as indicated by the posterior probability distribution, characterized by secular dynamical interactions without the involvement of mean motion resonances.

High-resolution methylome analysis uncovers stress-responsive genomic hotspots and drought-sensitive TE superfamilies in the clonal Lombardy poplar.

DNA methylation is environment-sensitive and can mediate stress responses. In long-lived trees, changing environments might cumulatively shape the methylome landscape over their lifetime. However, because high-resolution methylome studies usually focus on single environmental cues, it remains unclear to what extent the methylation responses are generic or stress-specific, and how this relates to their long-term stability. Here, we studied the methylome plasticity of a Populus nigra cv. 'Italica' clone that is widespread across Europe. Adult trees from a variety of geographic locations were clonally propagated in a common garden experiment, and the ramets were exposed to cold, heat, drought, herbivory, rust infection, and salicylic acid treatments. Through comprehensive whole-genome bisulfite sequencing, we analyzed stress-induced and naturally occurring DNA methylation variants. Stress-induced methylation changes predominantly targeted transposable elements. When occurring in CG/CHG contexts, the same regions were often affected by multiple stresses, suggesting a generic response of the methylome. Drought stress caused a distinct CHH hypermethylation response in transposable elements, affecting entire TE superfamilies near drought-responsive genes. Methylation differences in CG/CHG contexts that were induced by stress treatments showed striking overlap with methylation differences observed between trees from distinct geographical locations. Thus, we revealed genomic hotspots of methylation change that are not stress-specific and that contribute to natural DNA methylation variation, and we identified specific transposable element superfamilies that respond to a specific stress with possible functional consequences. Our results underscore the importance of studying the effects of multiple stressors in a single experiment for recognizing general versus stress-specific methylome responses.