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Daffodils (family Amaryllidaceae, genus Narcissus) are important ornamental plants produced primarily for cut flowers. In 2019, daffodils sales in the US were $6.26 M (USDA-NASS, 2019). In May 2021, four symptomatic daffodil plants (Narcissus pseudonarcissus) were sampled from a flowerbed (

We report the synthesis and X-ray solid-state structure of two eucalyptol derivatives. Both compounds form self-assembled dimers establishing C–H⋯O hydrogen bonds and H⋯H bonding interactions.

With the expansion of the world’s ethylene industry, the production of carbon five (C5) distillates has also gradually increased. C5 can be used to produce a series of high-value-added chemical pro...

Next-generation sequencing technologies have aided molecular detection and diagnosis of plant pathogens. Short read sequencing technologies can be expensive, time consuming, and lack portability. The Oxford Nanopore Technologies (ONT) MinION sequencer offers plant diagnosticians an alternative for whole-genome and transcriptome sequencing with the advantages of portability, rapid results and access to sequences generated, and relatively low cost. Although this company offers multiple sequencing products, most previous articles focused on comparing this technology with other sequencing technology (Sanger, Illumina) and not comparing ONT product performance. In this project, we explored the potential of using ONT’s kits without modifications for the sequencing of plant pathogens. We compared the performance of DNA library preparation protocols (1D versus 1D2 versus Rapid) and RNA library preparation protocols (cDNA PCR Sequencing versus Direct RNA) on the MinION sequencer and examined different data analysis approaches for two well-characterized plant pathogens of agricultural concern, Ralstonia solanacearum and plum pox virus. For bacterial DNA sequencing, the Rapid Sequencing kit had the lowest throughput but offered the shortest sample-to-sequence turnaround time. The cDNA PCR Sequencing kit was better suited for plant RNA viruses than the Direct RNA. Whole-genome assemblies using all tested kits provided accurate identification of the target pathogen when pure cultures or infected plant material was used. This technology offers a shorter sample-to-sequence timeline than previous technologies for both DNA and RNA samples. Data analysis can still be time- and resource-consuming, but we found that 1 h of data generation was sufficient for accurate identification of the target pathogens, which can alleviate computing resources because a full 48-h run of sequencing data is not required. With the decreasing costs of flow cells, MinION is now an additional tool to be considered by plant diagnosticians for whole-genome and transcriptome-based diagnostics.

Over geological timescales, variations in atmospheric O2 are typically attributed to the imbalance between the weathering of organic carbon (OC) and reduced sulfur on land, the major sink terms for atmospheric O2, and the burial of OC and reduced sulfur in marine sediments, the major source terms of O2 to the atmosphere. But the Fe cycle matters too. Using a compilation of C, Fe, S and H fluxes between the Earth9s exosphere, continents, and mantle reservoirs, I demonstrate that hydrothermal weathering of the oceanic lithosphere and volcanic degassing of SO2 have acted as net sinks of O2, amounting to ca. 2.7 ± 1.1 Tmol O2/y, over the Cenozoic. Near constancy of atmospheric oxygen concentrations over the same interval of time suggests that this igneous sink is compensated by the sedimentary cycles of C, S and Fe. The net subduction and accretion of OC likely made the dominant contribution and, therefore, operated as a net source of atmospheric O2 over the last 50-60 Myr. This result implies that redox steady-state in the Cenozoic is dynamically maintained by a net input of solar (photosynthetic) energy, ∼ 0.8 to 2 EJ/y, into the lithospheric cycles of C, S and Fe.

Ab initio molecular dynamics simulations were performed for Li+ conducting electrolytes based on trimethyl phosphates (TMP) and lithium bis(fluorosulfonyl)imide (Li+FSI−) salt in contact with a Li-...

The cycle of organic carbon through the atmosphere, oceans, continents and mantle reservoirs is a hallmark of Earth. Over geological time, chemical exchanges between those reservoirs have produced a diversity of reduced carbon materials that differ in their molecular structures and reactivity. This reactive complexity challenges the canonical dichotomy between the surface and deep, short-term and long-term organic carbon cycle. Old and refractory carbon materials are not confined to the lithosphere but are ubiquitous in the surface environment, and the lithosphere hosts various forms of reduced carbon that can be very reactive. The biological and geological pathways that drive the organic carbon cycle have changed through time; from a synthesis of these changes, it emerges that although a biosphere is required to produce organic carbon, mortality is required to ensure its export to the lithosphere, and graphitization is essential for its long-term stabilization in the solid Earth. Among the by-products of the organic carbon cycle are the accumulation of a massive lithospheric reservoir of organic carbon, the accumulation of dioxygen in the atmosphere and the rise of a terrestrial biosphere. Besides driving surface weathering reactions, free dioxygen has allowed the evolution of new metabolic pathways to produce and respire organic carbon. From the evolution of photosynthesis until the expansion of biomineralization in the Phanerozoic, inorganic controls on the organic carbon cycle have diversified, tightening the connection between the biosphere and geosphere. A review of the organic carbon cycle explores the interactions between the Earth’s surface and deeper reservoirs, the expanding inorganic controls on the organic carbon cycle, and how these links have strengthened through geological time.

In this chapter, the authors present a methodology for the formation and preparation of teams in order to participate in educational robotics competitions composed of five stages: recruitment, training, team conformation and preparation, prototyping, and competition day. The chapter begins with an introduction to educational robotics applied in schools and its use to implement design-based learning, followed by a description of the characteristics of the educational robotics kits and a brief description of the 5PER methodology used in the fourth stage, prototyping, with a description of the main robotics competencies worldwide. The five stages methodology is presented in detailed so it can be replicated by other educators around the world. The exposed methodology is based on the experience of the authors in the preparation of equipment to participate in various robotics competitions at the Faculty of Electrical and Electronic Engineering of the Universidad Nacional de Ingenieria Lima, Peru.

This chapter presents a methodology for the development of activities based on educational robotics: five phases of educational robotics (5PER). First, the authors describe how technology and science have evolved to this day, recognizing their importance, and how they have impacted the schools with approaches such as STEM. Then, the main theories and learning approaches that have driven to the use of educational robotics in schools are reviewed, as well as concepts of robotics, educational robotics, and the difference between them. Finally, each of the five phases are explained, and two practical examples of how to implement them in the development of learning activities are shown.

We evaluate the fullerene C

An ab initio molecular dynamics study of an electrochemical interface between a solid-state-electrolyte Li0.29La0.57TiO3 and Li-metal is performed to analyze interphase formation and evolution when external electric fields of 0, 0.5, 1.0 and 2.0 V A−1 are applied. From this electrochemical stability analysis, it was concluded that lithium-oxide (Li2O) and lanthanum-oxide (La2O3) phases were formed at the electrolyte/anode interphase. As the electric field increased, oxygen from the electrolyte diffused through the Li-metal anode, increasing the amount of O from deeper crystallographic planes of the electrolyte that reacted with Li and La. A strong reduction of Ti was expected from their Bader charge variation from +3.5 in the bulk to +2.5 at the interface. Due to the loss of Li atoms from the anode to form Li-oxide at the interphase, vacancies were created on the Li-metal, causing anode structure amorphization near the Li-oxide phase and keeping the rest of the anode structure as BCC. Therefore, the interface was unstable because of the continuous Li-oxide and La-oxide formation and growth, which were more pronounced when increasing the external electric field.

Atomistic and mesoscopic models are used to analyze cracking and stresses produced during charge of Si nanoparticles covered by a thin SEI film. Mechanical stresses coupled to chemical effects are investigated with classical molecular dynamics simulations and with a mesoscopic model. Rupture of the surface film is the main cause of capacity fade and damage evolution is strongly influenced by the structure of the solid film. For example, high currents can cause rapid amorphization and help preserving the bond integrity. But large damage occurs after the current is above a threshold. In agreement with the atomistic results, mesoscopic modeling reveals that rupture of the surface film is the primary cause of capacity fading for amorphous silicon exhibiting single phase diffusion. It also suggests that conjugated silicon-film fracture in crystalline silicon with two-phase diffusion further exacerbates this deterioration. Fracture damage is slightly diminished by decreasing the Young's modulus of the brittle coating for both amorphous and crystalline silicon; however, controlling the large volumetric expansion induced stress on surface film is crucial towards improving silicon anodes. Mitigation strategies examined by ab initio molecular dynamics and electronic density functional theory simulations show passivation effects of graphene and graphene oxide on lithiated Si surfaces.

We present an analytical method to quantify the absolute redox capacity, ΔO2, of geological materials. The protocol consists in a high temperature chalcometric titration by which a known amount of oxygen gas is exchanged between a solid state oxygen donor, CuO, and an oxygen acceptor, the sample, at elevated temper- ature. Calibration of the method using elemental C, native S and magnetite demonstrates that it effectively oxidizes C, S and Fe to their terminal oxidation state, C4+, S6+ and Fe3+, respectively. Because the metric is independent of processes of internal equilibration within the system, it can be used for quantitative assessments of redox fluxes in open geological systems, in the surface or deep Earth. Preliminary results suggest that the mass specific redox capacity, dO2, of geological materials span many orders of magnitude, ranging from less than 500 μmol O2/g for ultramafic rocks and lower crustal amphibolites, to more than 30000 μmol O2/g for black shales. This highlights a counterintuitive yet fundamental characteristic of our planet. Rocks characterized by elevated dO2 values are ubiquitous in the oxic Earth’s surface, while the upper mantle and lower crust are typically composed of rocks with much lower dO2. This work will contribute to provide a more nuanced and complete perspective on the sedimentary and geodynamic processes that have shaped the redox structure of the Earth.

The Neoproterozoic Paraguay Belt in mid-eastern Mato Grosso, western Brazil, records the geological evolution of the margins of western Gondwana. The lack of absolute geochronology for the Paraguay Belt has hampered both regional and global stratigraphic correlations. Here we determine the depositional age for the Peresopolis black slate that belongs to the base of the Cuiaba Group in the Paraguay Belt using Re-Os geochronometry. We obtain a narrow Re-Os age interval of 784 ± 8 Ma and a juvenile initial 187Os/188Os composition (Osi) of 0.15 ± 0.03. These data indicate that the Peresopolis black slate is Tonian in age and was deposited in a basin strongly influenced by the weathering of juvenile material, and potentially linked to the early rifting of Rodinia on western Gondwana. These slates record a time interval that is poorly represented in Brazil and with few counterparts in other Neoproterozoic basins globally. As such, our work is a foundation for future geochemical correlations and paleoenvironmental reconstructions of this critical transition of Earth history in Brazil and elsewhere.

Present Li-ion battery (LIB) technology requires strong improvements in performance, energy capacity, charging-time, and cost to expand their application to e-mobility and grid storage. Li-metal is one of the most promising materials to replace commercial anodes such as graphite because of its 10 times higher specific capacity. However, Li-metal has high reactivity with commercial liquid electrolytes; thus, new solid materials are proposed to replace liquid electrolytes when Li-metal anodes are used. We present a theoretical analysis of the charging process in a full nanobattery, containing a LiCoO2 cathode, a Li7P2S8I solid-state electrolyte (SSE), a Li-metal anode as well as Al and Cu collectors for the cathode and anode, respectively. In addition, we added a Li3P/Li2S film as a solid electrolyte interphase (SEI) layer between the Li-anode and SSE. Thus, we focus this study on the SEI and SSE. We simulated the charging of the nanobattery with an external voltage by applying an electric field. We estimated temperature profiles within the nanobattery and analyzed Li-ion transport through the SSE and SEI. We observed a slight temperature rise at the SEI due to reactions forming PS3− and P2S74− fragments at the interfaces; however, this temperature profile changes due to the charging current under the presence of the external electric field e = 0.75 V A−1. Without the external field, the calculated open-circuit voltage (OCV) was 3.86 V for the battery, which is within the range of values of commercial cobalt-based LIBs. This voltage implies a spontaneous fall of available Li-ions from the anode to the cathode (during discharge). The charge of this nanobattery requires overcoming the OCV plus an additional voltage that determines the charging current. Thus, we applied an external potential able to neutralize the OCV, plus an additional 1.6 V to induce the transport of Li+ from the cathode up to the anode. Several interesting details about Li+ transport paths through the SSE and SEI are discussed.

The compound 1,3,3-trimethyl-2-oxabicyclo[2.2.2]octan-9-ol (9-hydroxyeucaliptol) has been prepared and characterized by single-crystal X-ray diffraction analysis, infrared, Raman, and UV-visible spectroscopies. The molecular geometry of the title compound was also investigated theoretically by density functional theory (DFT) calculations to compare with the experimental data. The substance crystallizes in the trigonal crystal system, space group P3

The complete genome sequence of a U.S. isolate of a Tomato brown rugose fruit virus (ToBRFV) (CA18-01) was obtained through Illumina and MinION sequencing. The U.S. ToBRFV isolate shared a high nucleic acid sequence identity (>99%) with known ToBRFV isolates. Phylogenetic analysis revealed a tight cluster for ToBRFV isolates throughout the world, suggesting a short evolutionary history.

Ab initio molecular dynamics simulations were performed for Li+ conducting electrolytes based on 1M lithium hexafluorophosphate (Li+ PF 6 − ) in ethylene carbonate (EC)-ethylmethyl carbonate (EMC) (3:7wt) with 5 wt% vinylene carbonate (VC) in contact with Li-metal (electrode), finding a variety of products due to dissociations of all electrolyte components. The formed solid electrolyte interphase from electrolyte degradation arranges in an outer layer composed of denser materials (sitting over the anode surface) such as Li2(CH2O)2 from EC, Li2CO3, Li2C2H2 and Li2CO2 from VC, and Li2C3H5O2 and LiCH3O from EMC dissociations. Then follows an inner layer made of Li-binary compounds, Li3CO, Li2O and Li3C from EC, Li2O, Li2C2 and LiH from VC, and LiF and Li3P from PF 6 − dissociations. We calculated electron affinities of electrolyte molecules during their decomposition using a polarizable continuum model to consider solvent effects molecules degradation. PF 6 − has the highest first and second electron affinities, despite explicit Coulomb repulsion, which eventually dissociates the molecule right after capturing an electron from the metal-anode; therefore, PF 6 − is also the fastest to dissociate. EMC has the lowest first and second electron affinities, thus it is the least prone to accept electrons and the least likely to dissociate at the Li-metal interface.

The number of solute species required to describe the thermodynamic behavior of electrolytic fluids is a hindrance to the incorporation of aqueous geochemistry in petrological Gibbs energy minimization procedures. An algorithm is developed to overcome this problem. Beginning from the solute-free limit, chemical potentials, and phase stability are determined by minimization, the solute speciation and bulk fluid properties consistent with these chemical potentials are then computed and the procedure repeated until the chemical potentials converge. Application of the algorithm to a model for metamorphism of subducted sediment shows that accounting for solute chemistry does not change the conclusion based on molecular fluid models that a pervasive water flux from the subjacent mantle is required to explain island-arc carbon emissions by fluid-mediated slab decarbonation. This putative flux would deplete the sediment in potassium, limiting the capacity of the slab to transport water to greater depth and rendering it refractory to melting.

Reconstructing the redox state of the mantle is critical in discussing the evolution of atmospheric composition through time. Kimberlite-borne mantle eclogite xenoliths, commonly interpreted as representing former oceanic crust, may record the chemical and physical state of Archaean and Proterozoic convecting mantle sources that generated their magmatic protoliths. However, their message is generally obscured by a range of primary (igneous differentiation) and secondary processes (seawater alteration, metamorphism, metasomatism). Here, we report the Fe3+/ΣFe ratio and δ 18 O in garnet from in a suite of well-characterised mantle eclogite and pyroxenite xenoliths hosted in the Lace kimberlite (Kaapvaal craton), which originated as ca. 3 Ga-old ocean floor. Fe3+/ΣFe in garnet (0.01 to 0.063, median 0.02; n = 16 ) shows a negative correlation with jadeite content in clinopyroxene, suggesting increased partitioning of Fe3+ into clinopyroxene in the presence of monovalent cations with which it can form coupled substitutions. Jadeite-corrected Fe3+/ΣFe in garnet shows a broad negative trend with Eu⁎, consistent with incompatible behaviour of Fe3+ during olivine-plagioclase accumulation in the protoliths. This trend is partially obscured by increasing Fe3+ partitioning into garnet along a conductive cratonic geotherm. In contrast, NMORB-normalised Nd/Yb – a proxy of partial melt loss from subducting oceanic crust ( 1) – shows no obvious correlation with Fe3+/ΣFe, nor does garnet δ 18 O VSMOW (5.14 to 6.21‰) point to significant seawater alteration. Median bulk-rock Fe3+/ΣFe is roughly estimated at 0.025. This observation agrees with V/Sc systematics, which collectively point to a reduced Archaean convecting mantle source to the igneous protoliths of these eclogites compared to the modern MORB source. Oxygen fugacites ( f O 2 ) relative to the fayalite–magnetite–quartz buffer (FMQ) range from Δ log ⁡ f O 2 = FMQ-1.3 to FMQ-4.6. At those reducing conditions, the solubility of carbon in the fluids released by dehydration is higher than in fluids closer to FMQ. The implication is that Archean processes of C transport and deposition would have differed from those known in modern-style subduction zones, and diamond would have formed from methane-rich fluids. In addition, such reducing material could drive redox melting or freezing upon deep recycling and migration of CH4-bearing fluids into the ambient mantle.

Molecular dynamics simulations were performed to investigate the initial charging of a Li-ion nanobattery with a graphite anode and lithium hexaflourphosphate (LiPF6) salt dissolved in ethylene carbonate (CO3C2H4) solvent as the electrolyte solution. The charging was achieved through the application of external electric fields simulating voltage sources. A variety of force fields were combined to simulate the materials of the nanobattery, including the solid electrolyte interphase, metal collectors, and insulator cover. Some of the force field parameters were estimated using ab initio methods, and others were taken from the literature. We studied the behavior of Li-ions traveling from cathode to anode through electrolyte solutions of concentrations 1.15 and 3.36 M. Time-dependent variables such as energy, temperature, volume, polarization, and mean square displacement are reported; a few of these variables, as well as others such as current, resistance, current density, conductivity, and resistivity are r...

An

Battery capacity is highly related to ion-pairing mechanisms in electrolytes, since a cluster formation can lead to dead Li formation, reducing the number of charge carriers and leading to capacity fading. We use molecular dynamics simulations to model an electrolyte comprising trimethyl phosphate (TMP) solvent and a lithium bis(fluorosulfonyl)imide (LiFSI) salt, exploring effects of salt concentration on solvation and ion-transport. We simulate the LiFSI-TMP electrolyte for salt concentrations of 0.7, 1.43 and 3.82 molar. A statistical analysis was performed to study ion-pairing, clustering, diffusivity, conductivity, and coordination of Li-ions, providing insights into relations between molecular structures and transport properties. Molecular structure of ionic components changes as concentration increases, from a predominant solvent separated ion pair (SSIP) and contact ion pair (CIP) to aggregate salt (AGG) and ionic cluster formation. Given the formation of the ionic cluster, the diffusion mechanism followed by Li-ions changes from a hopping/exchange to a vehicular mechanism as concentration increases; this is reflected in a decrease of ionic conductivities. Ionicity was also calculated to reveal how the ionic motion changes from an uncorrelated to a correlated one as the salt concentration increases. We also compared our results with experimental calculations performed for similar electrolyte systems.

The chemistry of aqueous fluids controls the transport and exchange-the cycles-of metals and volatile elements on Earth. Subduction zones, where oceanic plates sink into the Earth's interior, are the most important geodynamic setting for this fluid-mediated chemical exchange. Characterizing the ionic speciation and pH of fluids equilibrated with rocks at subduction zone conditions has long been a major challenge in Earth science. Here we report thermodynamic predictions of fluid-rock equilibria that tie together models of the thermal structure, mineralogy and fluid speciation of subduction zones. We find that the pH of fluids in subducted crustal lithologies is confined to a mildly alkaline range, modulated by rock volatile and chlorine contents. Cold subduction typical of the Phanerozoic eon favours the preservation of oxidized carbon in subducting slabs. In contrast, the pH of mantle wedge fluids is very sensitive to minor variations in rock composition. These variations may be caused by intramantle differentiation, or by infiltration of fluids enriched in alkali components extracted from the subducted crust. The sensitivity of pH to soluble elements in low abundance in the host rocks, such as carbon, alkali metals and halogens, illustrates a feedback between the chemistry of the Earth's atmosphere-ocean system and the speciation of subduction zone fluids via the composition of the seawater-altered oceanic lithosphere. Our findings provide a perspective on the controlling reactions that have coupled metal and volatile cycles in subduction zones for more than 3 billion years7.

Ab initio and classical molecular dynamics simulations are performed for Li+ conducting electrolytes based on trimethyl phosphates (TMP) and lithium bis(fluorosulfonyl)imide (Li+FSI−) salt in contact with a Li-metal electrode. We focused on the electrolyte, interfacial electrolyte – Li-metal electrode, and lithium reference electrode – electrolyte – Li-metal electrode to study diffusion and activation energy barriers of the Li+ ion, electrochemical and thermal stability of the interface electrode electrolyte, and potential behavior of the Li-metal electrode, respectively. Our results show that in the most stable state Li+ ions are tetrahedrally coordinated to three TMPs and one FSI–. The decomposition pathway of the LiFSI salt when in direct contact with the Li-metal anode starts with defluorination of FSI− , rapidly losing F− to the lithium surface, forming LiF species. The remaining FSO2NSO2−2 with the addition of 2e− from the Limetal decomposes into SO2−2 and NFSO2−2. SO2−2 deposits on the Li-surface and decomposes into Li2O and Li2S. The remaining NFSO2−2 defluorinates, losing F− ion to the lithium surface, resulting in LiF and the remaining NSO2−1 deposits on the lithium surface and decomposes in the following picoseconds, forming several binary compounds such as Li3N, Li2S and Li2O. In contrast, when the salt is solvated by the TMP molecules, avoiding a direct contact with the Limetal electrode, only one defluorination occurs, decomposing the FSI− into FSO2NSO2−2 and a F–. A similar mechanism is followed when a second FSI− salt is in contact with this new formed SEI. The two anions remain stable as they are solvated by the TMP molecules. We also analyzed the open circuit potential energy (OCPE) of the Li-metal electrode during the SEI formation. OCPE is calculated from the average local potential profile difference within the Li-metal electrode and a pristine Li-crystal reference electrode (LRE). When no SEI is formed, the Li-metal electrode has an average OCPE of +0.36 eV vs LRE. Due to the formation of a SEI, the Li-metal electrode has an average OCPE between -0.07 and -0.21 eV vs LRE. The OCPE of the Li-metal electrode decreases by ~0.42 eV when a SEI is formed. Using the data obtained from the ab initio simulations and using machine learning algorithms such as classification and clustering a classical MD model was developed to study the SEI evolution as the charging process takes place in a battery using Li-metal as anode and the TMP/LiFSI as electrolyte. Figure 1

Quantification of carbon fluxes between solid Earth and its atmosphere is necessary to understand the global geological carbon cycle. Some of the main CO2 contributors are metamorphism and magmatic-mantle degassing. CO2 is discharged from active and quiescent volcanoes, fault zones, geothermal systems and CO2 rich groundwater. Here a new method for the estimation of the geogenic flux of CO2 from tectonically active regions, based on the volume, composition and age of travertine deposits, is proposed. The method is applied to the travertine deposits of western Central Italy where travertine deposition is driven by degassing of CO2 charged groundwater. Results show that the study areas are characterized, since Middle Pleistocene, by diffuse CO2 degassing processes with time averaged CO2 fluxes ranging between 1.24 ± 0.12 106 mol y−1 km−2 and 1.38 ± 0.42 106 mol y−1 km−2. These values are of the same order of magnitude of carbon dioxide fluxes measured by different methods in western central Italy and are higher than the global baseline CO2 flux from high heat flow regions. The review of the available 234U/230Th and 14C data shows that the CO2 degassing processes that affects western Central Italy nowadays were already active at least 350 Ka ago, proving that this region is a globally relevant case for the study of Earth degassing. Considering the widespread occurrence of travertine deposits in tectonically active areas worldwide, the proposed approach can be used as a reliable tool to estimate the CO2 flux in different geodynamic settings within system Earth.

The dataset presented in this article is used in the Quaternary Science Review research article "Evaluating the geogenic CO2 flux from geothermal areas by analysing Quaternary travertine masses. New data from western Central Italy and review of previous CO2 flux data" [1]. The present data article reports the physical properties and new compositional data of 86 travertine samples from Rapolano, Canino and Tivoli travertine deposits (Italy). The dataset include the following parameters: mass, volume, porosity, bulk density, CaCO3 content and insoluble fraction. The dataset is integrated with the photographic documentation of the sampling areas, the location and the stratigraphic position of each sample. ispartof: DATA IN BRIEF vol:25 ispartof: location:Netherlands status: published

Essential oils from aerial parts of

Fungi in the genus Monilinia cause brown rot disease of stone and pome fruits. Here, we report the draft genome assemblies of four important phytopathogenic species: M. fructicola, M. fructigena, M. polystroma, and M. laxa. The draft genome assemblies were 39 Mb (M. fructigena), 42 Mb (M. laxa), 43 Mb (M. fructicola), and 45 Mb (M. polystroma) with as few as 550 contigs (M. laxa). These are the first draft genome resources publicly available for M. laxa, M. fructigena, and M. polystroma.

Fluids exert a key control on the mobility of elements at high pressure and temperature in the crust and mantle. However, the prediction of fluid composition and speciation in compositionally complex fluid–rock systems, typically present in subduction zones, has been hampered by multiple challenges. We develop a computational framework to study the role of phase equilibria and complex solid-solutions on aqueous fluid speciation in equilibrium with rocks to 900 °C and 3 GPa. This is accomplished by merging conventional phase-equilibrium modeling involving electrolyte-free molecular fluids, with an electrostatic approach to model solute–solute and solute–solvent interactions in the fluid phase. This framework is applied to constrain the activity ratios, composition of aqueous solutes, and p H of a fluid in equilibrium with a pelite lithology. Two solvent compositions are considered: pure H2O, and a COH fluid generated by equilibration of H2O and graphite. In both cases, we find that the p H is alkaline. Disparities between the predicted peralkalinity of our fluid ( [ Na ] + [ K ] ) / [ Al ] ∼ 6 to 12 and results from independent mineral solubility experiments (∼2) point to the presence of Na–K–Al–Si polymers representing ca. 60 to 85% of the total K and Al content of the fluid at 600 °C and 2.2 GPa, and to an important fraction of dissolved Ca and Mg not accounted for in present speciation models. The addition of graphite to the system reduces the relative permittivity by ca. 40% at elevated T and low P, triggers the formation of C-bearing anions, and brings the p H closer to neutrality by up to 0.6 units at low T. This ionic C pool represents up to 45 mol% of the fluid ligands at elevated P, and is dominant at low P despite the low ionic strength of the fluid ( p H dependent processes that govern volatile, major and trace element partitioning between rocks and fluids in experimental or natural systems.

The presence of highly electronegative atoms in Li-ion batteries anticipates the formation of σ-hole regions that may strongly affect the ionic conductivity. The σ-hole consists of a region of positive electrostatic potential extending in the direction of the covalent bond between atoms of groups IV–VII due to anisotropic charge distribution. Graphite electrodes in Li-ion batteries that become halogenated due to the electrolyte, as well as some solid electrolyte materials, can exhibit these σ-holes. Since Li-ions should be able to drift in any part of the battery, the fact that they can be attracted and eventually absorbed by regions of strong negative potentials produced by high-electronegativity counterions becomes detrimental to ionic conductivity. Therefore, the presence of positive well-defined regions, repulsive to the Li-ions, might act as lubricant for Li-ions drifting through electrolytes, thus improving the Li-ion conductivity. In addition, the σ-holes might also have a strong effect on the formation of the passivating layer, known as the solid electrolyte interphase (SEI) at electrode surfaces, which is of paramount importance for the performance of rechargeable batteries. Here we investigate the existence of σ-holes on surfaces of graphite anodes and of a few solid electrolytes by examining the electrostatic potentials calculated using density functional theory.

Rechargeable lithium-ion batteries are the most popular devices for energy storage but still a lot of research needs to be done to improve their cycling and storage capacity. Silicon has been proposed as an anode material because of its large theoretical capacity of ∼3600 mAh/g. Therefore, focus is needed on the lithiation process of silicon anodes where it is known that the anode increases its volume more than 300%, producing cracking and other damages. We performed molecular dynamics atomistic simulations to study the swelling, alloying, and amorphization of a silicon nanocrystal anode in a full nanobattery model during the first charging cycle. A dissolved salt of lithium hexafluorophosphate in ethylene carbonate was chosen as the electrolyte solution and lithium cobalt oxide as cathode. External electric fields are applied to emulate the charging, causing the migration of the Li-ions from the cathode to the anode, by drifting through the electrolyte solution, thus converting pristine Si gradually into Li14Si5 when fully lithiated. When the electric field is applied to the nanobattery, the temperature never exceeds 360 K due to a temperature control imposed resembling a cooling mechanism. The volume of the anode increases with the amorphization of the silicon as the external field is applied by creating a layer of LiSi alloy between the electrolyte and the silicon nanocrystal and then, at the arrival of more Li-ions changing to an alloy, where the drift velocity of Li-ions is greater than the velocity in the initial nanocrystal structure. Charge neutrality is maintained by concerted complementary reduction-oxidation reactions at the anode and cathode, respectively. In addition, the nanobattery model developed here can be used to study charge mobility, current density, conductance and resistivity, among several other properties of several candidate materials for rechargeable batteries and constitutes the initial point for further studies on the formation of the solid electrolyte interphase in the anode. Graphical Abstract Nanobattery: LiCoO2 cathode, electrolyte solution of 1M Li+PF6- in ethylene carbonate, and Si crystal anode, which changes its volume due to lithiation during the first charge.

Metal lithium anodes are excellent alternatives for Li-ion batteries; however, nonuniform plating and swelling of the anode upon lithiation causes the growth of lithium dendrites, among few other problems. One possible solution to this, and perhaps the other problems, is the use of solid-state electrolytes. Our approach to analyze the use of solid-state electrolytes is based on performing a multiscale computational approach using quantum and classical molecular dynamics simulation techniques. We will present our study of the properties of the two above new types of materials for anodes and electrolytes as parts of a full nanobattery,1-4 whereby the properties of their solid electrolyte interphases will be determined. The speciation of several interfaces of lithium-metal anodes with electrolytes such as sulfides, halogenated phosphor-sulfides, halogenated nitrades, and few others of present interest will be presented. Since these simulations require the use of full nanobatteries, thus, they also require the presence of a cathode, and since sulfur and spinel structures are also potential alternatives, we will use related cathodes in our nanobatteries. Selis, L. A.; Seminario, J. M., Dendrite Formation in Anodes of Lithium-Ion Batteries. RSC – Advances, 2018, 8, 5255-5267. Galvez-Aranda, D. E.; Seminario, J. M., Simulations of a LiF Solid Electrolyte Interphase Cracking on Silicon Anodes Using Molecular Dynamics. J. Electrochem. Soc. 2018, 165, A717-A730. Ponce, V.; Galvez-Aranda, D. E.; Seminario, J. M., Analysis of a Li-Ion Nanobattery with Graphite Anode Using Molecular Dynamics Simulations. J. Phys. Chem. C 2017, 121, 12959–12971. Galvez-Aranda, D. E.; Ponce, V.; Seminario, J. M., Molecular Dynamics Simulations of the First Charge of a Li-Ion—Si-Anode Nanobattery. J. Mol. Model. 2017, 23, 120.

Understanding the geological carbon cycle remains a major scientific challenge, although studies dedicated to this issue, in particular those of J.J. Ebelmen in the mid 19th century, have existed for over 200 years. The exact scientific and social pathways leading to the construction of the contemporaneous carbon cycle requires further investigation, which in turn may provide valuable insights into the modern state of scientific knowledge. The present study contributes to this question by demonstrating that, following the discovery of the compound nature of carbonic acid by A.L. Lavoisier at the end of the 18th century, studies initially investigated the mechanisms of respiration and photosynthesis until they were recognized as exerting an antagonistic effect on the composition of air. In the early 19th century, the consequence of these studies at the global scale had been foreseen, and applied to investigate the stability of the atmospheric composition over time. These early steps were only concerned with the fate of carbonic acid through life processes. However, between 1820 and 1840, the works of A.L. Brongniard and J.B. Boussingault established that geologic processes, such as the burial of carbonaceous material (CM) in sedimentary rocks and the release of CO 2 by volcanoes, affect the composition of the atmosphere. By 1845, J.J. Ebelmen had brilliantly contributed to the emerging question of atmospheric composition by proposing that the alteration of silicates on continents and the precipitation of carbonates in the ocean should be considered as a sink of atmospheric CO 2 . He also used chemical formula of the time to quantify this process, which led him to mention a carbon rotation for the first time. The rotation of this element through geologic processes became, in itself, a matter worthy of investigation as was the composition of the atmosphere. We argue that J.J. Ebelmen's brilliant synthesis was made possible by the parallel development of the atomistic model of matter in the early 19th century by the influential works of J. Dalton and J.J. Berzelius. Finally, through the 19th century, the development of the theory of sediment subsidence and its application by T.S. Hunt to the rotation of carbon, along with the correlated experimental results obtained on the stability of materials at high pressure and temperature, led progressively to a synthetic model of the carbon cycle by V. Vernadsky in the early 20th century. A final shift to this model occurred with the emergence of the theory of plate tectonics and subduction zones that provides a major physical ground to account for C recycling between surfacial and deep reservoirs of the planet.

Morphological and chemical evidence of ancient life is widespread in sedimentary rocks retrieved from shallow depths in the Earth's crust. Metamorphism is highly detrimental to the preservation of biological information in rocks, thus limiting the geological record in which traces of life might be found. Deformation and increasing pressure/temperature during deep burial may alter the morphology as well as the composition and structure of both the organic and mineral constituents of fossils. However, microspore fossils have been previously observed in intensely metamorphosed rocks. It has been suggested that their small size, and/or the nature of the polymer composing their wall, and/or the mineralogy of their surrounding matrix were key parameters explaining their exceptional preservation. Here, we describe the remarkable morphological preservation of plant macrofossils in blueschist metamorphic rocks from New Zealand containing lawsonite. Leaves and stems can be easily identified at the macroscale. At the microscale, polygonal structures with walls mineralized by micas within the leaf midribs and blades may derive from the original cellular ultrastructure or, alternatively, from the shrinkage during burial of the gelified remnants of the leaves in an abiotic process. Processes and important parameters involved in the remarkable preservation of these fossils during metamorphism are discussed. Despite the excellent morphological preservation, the initial biological polymers have been completely transformed to graphitic carbonaceous matter down to the nanometer scale. This occurrence demonstrates that plant macrofossils may experience major geodynamic processes such as metamorphism and exhumation involving deep changes and homogenization of their carbon chemistry and structure but still retain their morphology with remarkable integrity even if they are not shielded by any hard-mineralized concretion.

Minerals formed by bio-oxidation of ferrous iron (Fe(II)) at neutral pH, their association with bacterial ultrastructures as well as their impact on the metabolism of iron-oxidizing bacteria remain poorly understood. Here, we investigated iron biomineralization by the anaerobic nitrate-dependent iron-oxidizing bacterium Acidovorax sp. strain BoFeN1 in the presence of dissolved Fe(II) using electron microscopy and Scanning Transmission X-ray Microscopy (STXM). All detected minerals consisted mainly of amorphous iron phosphates, but based on their morphology and localization, three types of precipitates could be discriminated: (1) mineralized filaments at distance from the cells, (2) globules of 100 ± 25 nm in diameter, at the cell surface and (3) a 40-nm thick mineralized layer within the periplasm. All of those phases were shown to be intimately associated with organic molecules. Periplasmic encrustation was accompanied by an accumulation of protein moieties. In the same way, exopolysaccharides were associated with the extracellular mineralized filaments. The evolution of cell encrustation was followed by TEM over the time course of a culture: cell encrustation proceeded progressively, with rapid precipitation in the periplasm (in a few tens of minutes), followed by the formation of surface-bound globules. Moreover, we frequently observed an asymmetric mineral thickening at the cell poles. In parallel, the evolution of iron oxidation was quantified by STXM: iron both contained in the bacteria and in the extracellular precipitates reached complete oxidation within 6 days. While a progressive oxidation of Fe in the bacteria and in the medium could be observed, spatial redox (oxido-reduction state) heterogeneities were detected at the cell poles and in the extracellular precipitates after 1 day. All these findings provide new information to further the understanding of molecular processes involved in iron biomineralization by anaerobic iron-oxidizing bacteria and offer potential signatures of those metabolisms that can be looked for in the geological record.

Rechargeable lithium-ion batteries are one of the most used devices for energy storage but still a lot of researcher needs to be performed to improve their cycling and storage capacity. The most used material anodes is graphite with a theoretical capacity of 372 mAh/g. Thus, silicon have been proposed as an anode material because its large capacity of 3,579 mAh/g. Several experimental and theoretical-computational works have been done to find out how silicon behaves during lithiation (charging of the battery), especially when the silicon anode increases its volume up to 300% due to the lithiation process. In order to understand the mechanics and chemistry of silicon electrodes and to prevent undesirable effects such as the cracking of the anode, research have been performed on nanoscale approaches to a fully nanobattery. We study both, the graphite and the silicon nanocrystal anodes, performing molecular dynamics atomistic simulations. In this effort in progress we are focusing on the mechanical properties, such as swelling, alloying mechanism, and amorphization of the anode material during the first charging cycle and also the electrical properties such as polarization and current. The nanobattery includes LiCoO2 cathode; the electrolyte solution contains ethylene carbonate, as well as hexafluorophosphate and Li-ions. In these preliminary models, a solid electrolyte interface (SEI) is not included yet. An external electric field is applied to emulate the charging process causing the migration of the Li-ions from the cathode, diffusing through the electrolyte to finally get into the anode. We immediately observe during charging (i.e., when an external electric field is applied) of the nanobattery, the Si anode changes gradually into a LiSi alloy at temperatures below 360 K, using an NVT ensemble. We obtained the drift velocity of the Li-ions during the amorphization of the silicon nanocrystal as the original volume of the anode increases. For the graphite anode, the full lithiated state is achieve when the initial structure C changes into LiC6, storing the Li-ion between the layers of the graphite, thus we were able to compare energy, temperature, and electrical properties such as current, resistance, current density, conductivity and resistivity. Our model can be used to study the mechanisms taking place in the electrolyte, cathode, and especially for new materials for the anode.

In 1992, when the last Chilean census was taken, 240,000 homes in the country were without electricity. During the last few years, several systems have been implemented in rural areas to generate power: small hydraulic plants in southern Chile to take advantage of a greater hydraulic capacity, and solar home systems (SHS) in northern Chile where solar radiation is more abundant. The SHS consists of a photovoltaic panel, a charge regulator, a battery, lights, a socket and switches. There are no set standards for the installation of the SHS, and the exact number of systems installed and their faults (if any) are not known. Nor is it clear if the expectations of the financing organizations or the users have been fulfilled. Until now, there has not been any study of the impact that these systems have had on the population. This work corresponds to the first part of a study suggesting standards for the installation of the SHS, and also considers some additional general and specific issues related to photovoltaic electrification. The objective of this work is to evaluate the social and technical advantages and disadvantages of the existing photovoltaic systems in the commune of Camarones. The systems are identified and classified, and their faults and virtues are determined in order to present possible improvements to those systems.

International audience; Carbon is transported from Earth's surface into its interior at subduction zones. Carbonates in sediments overlying hydrothermally altered rocks (including serpentinites) within the subducted slab are the main carriers of this carbon1. Part of the carbon is recycled back to the surface by volcanism, but some is transferred to the deep Earth1, 2. Redox transformations during shallow subduction control the transfer and long-term fate of carbon, but are poorly explored1, 3. Here we use carbon stable isotopes and Raman spectroscopy to analyse the reduction of carbonate in an exhumed serpentinite-sediment contact in Alpine Corsica, France. We find that highly crystalline graphite was formed during subduction metamorphism and was concentrated in the sediment, within a reaction zone in direct contact with the serpentinite. The graphite in this reaction zone has a carbon isotopic signature (δ13C) of up to 0.8±0.1‰, similar to that of the original calcite that composed the sediments, and is texturally associated with the calcium-bearing mineral wollastonite that is also formed in the process. We use mass-balance calculations to show that about 9% of the total carbonaceous matter in the sedimentary unit results from complete calcite reduction in the reaction zone. We conclude that graphite formation, under reducing and low-temperature conditions, provides a mechanism to retain carbon in a subducting slab, aiding transport of carbon into the deeper Earth.