A mathematical model of plant nutrient uptake

The classical model of plant root nutrient uptake due to Nye. Tinker and Barber is developed and extended. We provide an explicit closed formula for the uptake by a single cylindrical root for all cases of practical interest by solving the absorption-diffusion equation for the soil nutrient concentration asymptotically in the limit of large time. We then use this single root model as a building block to construct a model which allows for root size distribution in a more realistic plant root system, and we include the effects of root branching and growth. The results are compared with previous theoretical and experimental studies

Inner-shell electron spectroscopy and chemical properties of atoms and small molecules

The program has been concerned with gas-phase carbon 1s photoelectron spectroscopy of a number of molecules of potential chemical interest. The primary goals have been to determine carbon 1s ionization energies with a view of relating these to other chemical properties such as electronegativity, acidity, basicity, and reactivity, in order to provide a better understanding of these fundamental properties. The role of electron-donating (methyl) and electron-withdrawing (fluoro) substituents on the carbon 1s ionization energies of substituted benzenes has been studied., and these results have been related to measurements of the reactivities of the same molecule as well as to their affinities for protons (basicity). Opportunities for investigation in unplanned areas have arisen, and the program has been modified to take advantage of these. One has been the realization that, under certain circumstances, inner-shell ionization energies may depend on the molecular conformation. Several examples of this phenomenon have been investigated and it has been shown that this technique provides a tool for the measurement of the energy differences between different conformers of the same substance. The other has been the demonstration that photoelectron recoil can lead to the excitation of vibrational modes that are forbidden in the normal view of photoemission and to rotational heating of the molecule that increases with the energy of the exciting radiation

Small Molecule Photoelectron Spectroscopy : Recoil Effects, Stoichiometric Surprises, and Double-Core-Hole Ionization

This is an author's peer-reviewed final manuscript, as accepted by the publisher. The published article is copyrighted by Elsevier and can be found at: https://doi.org/10.1016/j.elspec.2012.12.004Three features of small-molecule photoelectron spectroscopy are considered (1) The atom from which a photoelectron is emitted must have a recoil momentum equal to that of the emitted electron. This is shared among the various modes of motion of the ion, leading to rotational and vibrational excitation. Furthermore, any initial velocity of the atom (due to either translational, rotational, or vibrational motion) will lead to Doppler broadening. These effects are observable and can, in general, be accounted for by simple models. In some cases, however, the simple models fail and a deeper insight is necessary. (2) Inner-shell photoionization is essentially an atomic process, and it is expected that the intensity for emission of a photoelectron from the core of an atom in a molecule will be independent of its chemical environment. Recent measurements on the carbon 1s photoelectron spectra of three chloroethanes show that this is not the case. At energies not far above the ionization threshold there are strong oscillations of the intensity ratio (C[subscript Cl]/C[subscript H]) with increasing photon energy. These are similar to those seen in EXAFS and can be accounted for by considering backscattering of the photoelectrons from the chlorine atoms. Moreover, even at high energies the cross section for ionization has been found to depend on the chemical environment of the atom. These results have important consequences for the use of inner-shell electron spectroscopy for quantitative analysis. (3) Single-core-hole ionization energies have long been used as a tool for investigating chemical phenomena. Double-core-hole ionization energies provide additional chemical information. By combining the single-hole and double-hole ionization energies it is possible to determine the effects of the initial-state charge distribution and final-state charge rearrangement on the chemical shifts and on other chemical properties. Until recently double-core-hole ionization energies have not been experimentally accessible for first-row elements. New experimental techniques have, however, made it possible to measure these not only for single sites in a molecule, but also for two different sites in the same molecule. The chemical information that can be obtained from such measurements is discussed

Calibration of oxygen 1s ionization energies. Accurate energies for CO2, H2O, CO, and O2

Access to accurate reference data is a prerequisite in order to translate chemical shifts to an absolute scale for inner-shell ionization energies. Calibration standards for oxygen 1s (O 1s) ionization energies are less well established than, for instance, for carbon 1s. To improve upon this situation, adiabatic and vertical O 1s ionization energies for gaseous carbon dioxide (CO2) are critically reviewed and used to establish the most accurate values currently available: 541.085(17) and 541.253(17) eV, respectively. Combining these with new precise measurements of shifts in O 1s ionization energies for H2O, CO, and O2 allows us to establish equally accurate absolute ionization energies for these molecules as for CO2. The resulting adiabatic and vertical energies are 539.728(17) and 539.827(17) eV for H2O, 542.439(17) and 542.495(17) eV for CO, 543.285(17) and 543.294(17) eV for O2 (4Σ final state), and 544.338(17) and 544.423(17) eV for O2 (2Σ final state). It is proposed that O 1s in CO2 be adopted as a standard of higher precedence, and that H2O, CO, and O2 be used also. The O 1s ionization energies in these molecules occur in the range 540–543 eV. These proposed standards should provide optimal internal calibration for a wide range of oxygen-containing compounds.publishedVersio

Association of Cross-Reactive Antibodies Targeting Peptidyl-Arginine Deiminase 3 and 4 with Rheumatoid Arthritis-Associated Interstitial Lung Disease

Background: A subset of rheumatoid arthritis (RA) patients have detectable antibodies directed against the peptidyl-arginine deiminase (PAD) enzyme isoforms 3 and 4. Anti-PAD3/4 cross-reactive antibodies (anti-PAD3/4XR) have been shown to lower the calcium threshold required for PAD4 activation, an effect potentially relevant to the pathogenesis of RA-associated interstitial lung disease (ILD). Methods: RA patients underwent multi-detector computed tomography (MDCT) of the chest with interpretation by a pulmonary radiologist for ILD features. A semi-quantitative ILD Score (range 0–32) was calculated. Concurrent serum samples were assessed for antibodies against PAD by immunoprecipitation with radiolabeled PAD3 and PAD4. Results: Among the 176 RA patients studied, any ILD was observed in 58 (33%) and anti-PAD3/4XR was detected in 19 (11%). The frequency of any ILD among those with anti-PAD3/4XR was 68% vs. 29% among those with no anti-PAD (crude OR = 5.39; p = 0.002) and vs. 27% among those with anti-PAD4 that was not cross-reactive with PAD3 (crude OR = 5.74; p = 0.001). Both associations were stronger after adjustment for relevant confounders (adjusted ORs = 7.22 and 6.61, respectively; both p-values<0.01). Among ever smokers with anti-PAD3/4XR, the adjusted frequency of any ILD was 93% vs. 17% for never smokers without the antibody (adjusted OR = 61.4; p = 0.001, p-value for the interaction of smoking with anti-PAD3/4XR<0.05). Conclusions: The prevalence and extent of ILD was markedly higher among RA patients with anti-PAD3/4 cross-reactive antibodies, even after accounting for relevant confounders, particularly among ever smokers. These findings may suggest etiopathologic mechanisms of RA-ILD, and their clinical utility for predicting ILD warrants additional study

Groundwater mixing in a heterogeneous multilayer aquifer driven by geogenic CO2 fluxes: Evidence from chemical and isotopic composition of Ferrarelle waters (Riardo Plain, southern Italy)

The successful management of carbon in the Earth's crust is critical for mitigating the increase of anthropogenic CO2 in the atmosphere. Carbon Capture and Storage (CCS) requires an understanding of the behavior of carbon in the crust and the development of robust monitoring techniques to constrain the movement, mechanisms, and pathways for any potential CO2 leakage. Here, we examine an aquifer from the Riardo Plain (Campania Region, southern Italy), which serves as a suitable natural analogue for CO2 migration to the critical zone (i.e., shallow crust and aquifers) and as a case study to evaluate the geochemical processes that occur when CO2-saturated fluids mix with freshwater in shallow aquifers. We investigate the behavior of various geochemical constituents (major and trace elements, δ18O–H2O, δ13C-DIC, and Rn content). Water from this area has a high degree of mineralization (EC 2500–3000 μS/cm), high HCO3- (~2.5 g/L), is saturated with respect to CaCO3, and is enriched in alkali ions (e.g., Na+ + K+). The high degree of mineralization occurs in groundwater that discharges from the basal aquifer of the Roccamonfina volcanic edifice (~6 km NW), with vast CO2 inputs that promote host rock leaching. Superficial volcanic aquifers are recharged by fresh meteoric precipitation when groundwater flows from carbonates at the edge of the plain to aquifers hosted in the southeastern slope of the Roccamonfina volcano. The presence of normal faults in this area permits natural upwelling of CO2-rich groundwater, which locally mixes with shallow freshwater present within the upper volcanic succession. Significant (R > 0.8) linear correlations between conservative elements suggest that groundwater geochemistry is dominated by a mixture of two main endmembers: (i) deep/mineralized waters and (ii) shallow/diluted waters. The intrusion of freshwater to volcanic aquifers induces oxidation, leading to adsorption of select elements (e.g., As and Ba) onto Fe-oxyhydroxide precipitates within these aquifers. Geochemical modeling suggests that CO2 saturation approaches 3 g/L, which agrees with direct measurements of CO2 flux. We conclude that our conceptual geochemical model helps to constrain mixing of CO2 with freshwater and to diagnose the secondary geochemical processes that influence aqueous geochemistry within CO2-influenced groundwater

The Campo de Calatrava Volcanic Field (central Spain): Fluid geochemistry in a CO2-rich area.

The Campo de Calatrava Volcanic Field (CCVF) located in central-southern Spain (along with Selva-Emporda in Catalonia, NE Spain) is regarded as one of the most important CO emitting zones in Peninsular Spain. Here, we report and evaluate new molecular and isotopic geochemistry of thermal waters and COrich gas discharges from the CCVF. Locally, these CO-rich fluid emissions represent the remnants of the past volcanic activity that affected this area from the late Miocene through the Quaternary, with the most recent events occurring in the Holocene. The locations of discharging fluids and previous volcanic centers appear to be aligned along well-defined NW-SE and NNW-SSE lineaments, with subordinate trends in the ENE-WSW direction. The chemical and isotopic composition of the thermal waters suggests a meteoric origin, dominated by three distinct geochemical facies: 1) HCO-Mg(Ca) type waters, associated with a relatively shallow aquifer and related to the interaction of meteoric waters with CO-rich gases, alkaline volcanic products, and sedimentary formations, 2) SO(Cl)-Ca(Mg) type waters, which stems from the two rivers (Guadiana and Jabalón) that drain Triassic evaporitic rocks before entering the study area, and 3) HCO-Na type waters, hosted in deep geopressurized CO-rich reservoirs within the Ordovician basement rocks. The Sr/Sr isotopic compositions (ranging between 0.70415 and 0.71623) and δS-SO values (+10.7 to +18.3‰ vs. CDT) of CO-rich fluids are consistent with interactions between water and either the Paleozoic basement, Triassic evaporites, Quaternary volcanic rocks, or a combination thereof. Dissolution of a CO-rich gas phase into the aquifer produces low pH values (down to 5.4) and enhances water-rock interactions causing relatively high salinity (Total Ionic Salinity: up to ∼185 meq/L). Carbon dioxide is by far the most abundant gas constituent (up to 992 mmol/mol) and is dominated by mantle-derived sources as indicated by the combination of relatively high helium isotopic ratios (up to 2.7 R/Ra), high isotopic ratios of carbon in CO (ranging between −6.8 and −3.2‰ V-PDB), and the carbon isotopic signature of TDIC (from −6.8 to +2.2‰ vs. VPDB). In the last two decades, numerous (CO-rich) gas blowouts have occurred in the area during well drillings, suggesting the presence of a geopressurized gas reservoir at relatively shallow depth.The Municipality of Almagro is gratefully acknowledged for the help provided during the sampling activities. We would like to thank Dr. Luis Perez del Villar for his help during the first sampling fieldwork at CCVF. We wish to thank D. Melero Cabañas who accompanied us in the field to collect the water samples during the first survey. Many thanks are also due to the personnel of Amphos21 (J. Bruno, A. Cedez, F. Grandia) and Ciudad de la Energia (D. Angel) and F. Capecchiacci (Dept. Earth Science of Florence) for their help during the second survey. We would like to acknowledge the comments and suggestions provided by two reviewers, who greatly improved an early version of the manuscript. This work was partially funded by Ciudad de la Energia (Resp. OV; Grant contract: ALM-08-006) and the Laboratory of Stable Isotopes and Fluid Geochemistry of the Department of Earth Sciences (University of Florence)

Epidemiology of injuries from fire, heat and hot substances: global, regional and national morbidity and mortality estimates from the Global Burden of Disease 2017 study

Background Past research has shown how fires, heat and hot substances are important causes of health loss globally. Detailed estimates of the morbidity and mortality from these injuries could help drive preventative measures and improved access to care. Methods We used the Global Burden of Disease 2017 framework to produce three main results. First, we produced results on incidence, prevalence, years lived with disability, deaths, years of life lost and disability-adjusted life years from 1990 to 2017 for 195 countries and territories. Second, we analysed these results to measure mortality-to-incidence ratios by location. Third, we reported the measures above in terms of the cause of fire, heat and hot substances and the types of bodily injuries that result. Results Globally, there were 8 991 468 (7 481 218 to 10 740 897) new fire, heat and hot substance injuries in 2017 with 120 632 (101 630 to 129 383) deaths. At the global level, the age-standardised mortality caused by fire, heat and hot substances significantly declined from 1990 to 2017, but regionally there was variability in age-standardised incidence with some regions experiencing an increase (eg, Southern Latin America) and others experiencing a significant decrease (eg, High-income North America). Conclusions The incidence and mortality of injuries that result from fire, heat and hot substances affect every region of the world but are most concentrated in middle and lower income areas. More resources should be invested in measuring these injuries as well as in improving infrastructure, advancing safety measures and ensuring access to care. This is an open access article distributed in accordance with the Creative Commons Attribution 4.0 Unported (CC BY 4.0) license, which permits others to copy, redistribute, remix, transform and build upon this work for any purpose, provided the original work is properly cited, a link to the licence is given, and indication of whether changes were made

IL-10 production differentially influences the magnitude, quality, and protective capacity of Th1 responses depending on the vaccine platform

The quality of a Th1 response can be a prospective correlate of vaccine-mediated protection against certain intracellular pathogens. Using two distinct vaccine platforms, we evaluate the influence of interleukin (IL) 10 production on the magnitude, quality, and protective capacity of CD4+ T cell responses in the mouse model of Leishmania major infection. Multiparameter flow cytometry was used to delineate the CD4+ T cell production of interferon (IFN) γ, IL-2, tumor necrosis factor (TNF), and IL-10 (or combinations thereof) after vaccination. Immunization with a high dose of adenovirus (ADV) expressing leishmanial proteins (MML-ADV) elicited a limited proportion of multifunctional IFN-γ+IL-2+TNF+ Th1 cells, a high frequency of IL-10–producing CD4+ T cells, and did not protect against subsequent challenge. Surprisingly, in the absence of IL-10, there was no change in the magnitude, quality, or protective capacity of the Th1 response elicited by high-dose MML-ADV. In contrast, after immunization with MML protein and CpG (MML + CpG), IL-10 limited the production of IL-12 by DCs in vivo, thereby decreasing the generation of multifunctional Th1 cells. Consequently, three immunizations with MML + CpG were required for full protection. However, inhibiting IL-10 at the time of immunization enhanced the magnitude and quality of the Th1 response sufficiently to mediate protection after only a single immunization. Overall, we delineate distinct mechanisms by which vaccines elicit protective Th1 responses and underscore the importance of multifunctional CD4+ T cells

Electronic Properties of Chlorine, Methyl, and Chloromethyl as Substituents to the Ethylene Group-Viewed from the Core of Carbon

“Substituent effects” is an important and useful concept in organic chemistry. Although there are many approaches to parametrizing the electronic and steric effects of substituents, the physical basis for the parameters is often unclear. The purpose of the present work is to explore the properties of chemical shifts in carbon 1s energies as a well-defined basis for characterizing substituents to an ethylene C═C moiety. To this end, high-resolution carbon 1s photoelectron spectra of six chloro-substituted ethenes and seven chloro-substituted propenes have been measured in the gas phase. Site-specific adiabatic ionization energies have been determined from the spectra using theoretical ab initio calculations to predict the vibrational structures. For two molecules, 3-chloropropene and 2,3-dichloropropene, the spectral analyses give quantitative results for the conformer populations. The observed shifts have been analyzed in terms of initial-state (potential) and relaxation effects, and charge relaxation has also been analyzed by means of natural resonance theory. On the basis of core-level spectroscopy and models, chlorine, methyl, and chloromethyl have been characterized in terms of their effect on the carbon to which they are attached (α site) as well as the neighboring sp² carbon (β site). The derived spectroscopic substituent parameters are characterized by both inductive (electronegativity) effects and the ability of each substituent to engage in electron delocalization via the π system. Moreover, the adopted approach is extended to include substituent–substituent interaction parameters