Association between low C-peptide and fragility fractures in postmenopausal women without diabetes.

PURPOSE: C-peptide has been shown to exert several, previously unknown, biological effects. A recent cross-sectional study demonstrated an association between low C-peptide serum levels and low lumbar bone density of postmenopausal women not affected by diabetes. To date, very little research attention has been directed toward the association between C-peptide and osteoporotic fractures. To contribute toward filling this gap, we investigated the association between C-peptide and fractures in postmenopausal women. METHODS: A cohort of 133 non-diabetic postmenopausal women with and without a history of fractures was evaluated in this cross-sectional investigation. Standardized interviews were performed to gather information on the patients' fracture history. All of the participants underwent a bone mineral density assessment by DXA, radiographs, and a serum C-peptide measurement. RESULTS: Thirty-four women presented fractures. Bivariate analysis revealed an inverse correlation between C-peptide and fractures (r = -0.27, p = 0.002). A significant difference in mean C-peptide levels was also found between women with vs. without fractures (p = 0.01, adjusted for age, BMI and glucose). Logistic regression analysis showed that C-peptide levels, femoral and vertebral BMD were all negatively associated with fracture status (B = -1.097, ES = 0.401, p = 0.006, 95% CI 0.15-0.73; B = -15.6, SE = 4.17, p < 0.001, CI 0.001-0.002; B = -24.8, SE = 5.23, p < 0.001, CI 0001-0.002; respectively). CONCLUSIONS: This study confirms an inverse association between serum C-peptide levels and a history of fractures in postmenopausal women without diabetes. These results suggest that C-peptidemay exert an effect on bone mineral density. However, further large-scale studies are needed to corroborate this finding and investigate the potential underlying mechanisms involved.

Selection of a halophytic plant for assessing the phytotoxicity of dredged seaport sediment stored on land.

The filling of dry quarries in coastal areas with sediments dredged in seaports represents a potentially interesting method of recycling of these materials. However, this recycling requires the prior carrying out of an Environmental Risk Assessment of the scenario concerned. For this, the question arose as to the type of plants capable of developing on the surface of such a deposit and the method to implement for assessing the possible phytotoxicity of dredged sediments. To answer this question, we chose to work with halophytic plants to be free from the salt-related effect and to assess only the effect related to the toxic compounds present. Based on the objectives set, these works led to the use of common plants of the French coast, with direct seeding, and with pollution-sensitive plants. Three species of angiosperms, Armeria maritima, Anthemis maritima and Plantago coronopus, were finally tested. As a result of this work, Armeria maritima was retained as the most suitable plant for testing the possible phytotoxic effect of dredged marine sediments stored on land. The results obtained with this plant are as follows: germination of 40 % of the seeds in 31 days, produced biomass of 493 mg FW in 6 months and a capacity to bioaccumulate metal pollutants in roots with 350 and 720 mg/kg DW for Zn and Cu, respectively.

Molecular dynamics study of hydrogen isotopes at the Be/BeO interface.

Molecular dynamics simulations are used to investigate the behaviour of D atoms at two interfaces between beryllium (Be) and beryllium oxide (BeO). After relaxation of the simulation cell, there are (a) localised defects at the interface and (b) a hexagonal misfit dislocation network creating a succession of compressed and expanded area from each side of the interface. The simulations between 750 K and 1500 K for tens to hundreds of nanoseconds show that both interfaces act as trapping sites for D atoms. The simulations also show that D atoms tend to migrate in the material where the hydrogen isotope solubility is the highest as predicted by thermodynamics. However, the simulations also shows that there are additional kinetic barriers (D trapping sites, D2formation/dissociation in BeO) that slow down the path to equilibrium. These additional kinetic barriers may influence the fuel retention and permeation in Be materials.

Symptoms of Orthorexia Nervosa are associated with time spent on social media: a web-based survey in an Italian population sample.

OBJECTIVE: Orthorexia Nervosa (ON) is an eating disorder of growing interest that is characterized by an obsession with healthy eating. Nowadays, people spend an increasing amount of time on social media, which may negatively impact eating behaviors. The aim of this study was to investigate the relationship between social media usage and risk of ON. SUBJECTS AND METHODS: We conducted an online survey using the 10-item Italian-Düsseldorf Orthorexia Scale questionnaire (I-DOS). A total of 4,107 individuals participated and were classified according to sex, age, education level, marital status, BMI, main occupation, and diet. RESULTS: The prevalence of ON was 28.5%. Participants who reported using social media for over 60 minutes per day had a higher prevalence of ON than those using social media for less than 15 minutes per day. CONCLUSIONS: The results of this study suggest that longer time spent on social media is associated with ON.

Mediterranean Diet In Healthy Aging.

The World elderly population is expected to double before 2050. Unhealthy habits and unhealthy lifestyles are commonly associated with age-related diseases or their worsening. Modification in daily lifestyle and diet may help preventing age-related diseases onset and efficiently affecting their evolution, thus promoting the Healthy Aging process, concept recently coined to describe the disease-free aging process. This review highlights the role of nutrition science in promoting healthy aging. Since the Mediterranean Model demonstrated to be a useful style in supporting healthy aging, promotion of this correct lifestyle by health policies seems to be the best approach to achieve this target.

Study of the sticking of a hydrogen atom on a graphite surface using a mixed classical-quantum dynamics method.

The sticking of one hydrogen atom chemisorbed on the (0001) graphite surface is investigated using a mixed classical-quantum method. The phonon modes of the system in the collinear scattering approach are included in the dynamics calculations. The vibrational degrees of freedom of the surface (phonons) are treated classically, while the H-surface motion is treated using a one-dimensional quantum wave packet propagation method. The sticking probabilities are calculated and the individual contributions of the phonon bands to the collision dynamics are analyzed for surface temperatures of 10, 150, and 300 K and hydrogen kinetic energies ranging from 0.13 to 1.08 eV. An analytical form of the sticking probability as a function of the surface temperature is also proposed.

Analytical bond order potential for simulations of BeO 1D and 2D nanostructures and plasma-surface interactions.

An analytical interatomic bond order potential for the Be-O system is presented. The potential is fitted and compared to a large database of bulk BeO and point defect properties obtained using density functional theory. Its main applications include simulations of plasma-surface interactions involving oxygen or oxide layers on beryllium, as well as simulations of BeO nanotubes and nanosheets. We apply the potential in a study of oxygen irradiation of Be surfaces, and observe the early stages of an oxide layer forming on the Be surface. Predicted thermal and elastic properties of BeO nanotubes and nanosheets are simulated and compared with published ab initio data.

Hydrogen in beryllium oxide investigated by DFT: on the relative stability of charged-state atomic versus molecular hydrogen.

The behavior of hydrogen in perfect wurtzite beryllium oxide is herein investigated by means of electronic structure calculations based on density functional theory. The formation energies of the following set of states of hydrogen (H0, H+, H-, H2, [Formula: see text], [Formula: see text]) are computed and their solubility is established as a function of temperature and pressure with emphasis given to conditions relevant for hydrogen-implanted materials. It is found that all magnetic states H0, [Formula: see text], [Formula: see text] are unstable, while the relative stability of the non-magnetic states depends on the thermodynamic conditions: H2 prevails above temperatures around 900 K at standard pressure, which is the lowest temperature in experiments measuring the diffusion coefficient of hydrogen in wurtzite beryllium oxide. Under hydrogen implantation, the total concentration of hydrogen is fixed by the implantation source; it is found that molecular hydrogen prevails starting from a very low total concentration in hydrogen (as low as 10-40 at.fr.). Finally, the diffusion coefficient of H2 in beryllium oxide is calculated and the results are compared with previous experimental data.

Hydrogen retention in beryllium: concentration effect and nanocrystalline growth.

We herein report on the formation of BeD2 nanocrystalline domes on the surface of a beryllium sample exposed to energetic deuterium ions. A polycrystalline beryllium sample was exposed to D ions at 2 keV/atom leading to laterally averaged deuterium areal densities up to 3.5 10(17) D cm(-2), and studied using nuclear reaction analysis, Raman microscopy, atomic force microscopy, optical microscopy and quantum calculations. Incorporating D in beryllium generates a tensile stress that reaches a plateau at ≈1.5 10(17) D cm(-2). For values higher than 2.0 10(17) cm(-2), we observed the growth of ≈90 nm high dendrites, covering up to 10% of the surface in some zones of the sample when the deuterium concentration was 3 × 10(17) D cm(-2). These dendrites are composed of crystalline BeD2, as evidenced by Raman microscopy and quantum calculations. They are candidates to explain low temperature thermal desorption spectroscopy peaks observed when bombarding Be samples with D ions with fluencies higher than 1.2 10(17) D cm(-2).

Hydrogen retention and diffusion in tungsten beryllide.

Beryllide compounds are often used in various domains because they are more resilient to oxidation than pure beryllium and at the same time they keep some of the properties of this metal. Nevertheless, the data about their properties during atomic hydrogen exposure are very scarce: numerous experiments have been conducted in the past few years on solid hydride deposition under beryllium-seeded plasma action or on energetic hydrogen implantation into metallic beryllium; many others have been devoted to hydrogen retention and diffusion in tungsten. There have been fewer studies about hydrogen interaction with the alloys of these metals, although the beryllium-tungsten mixed compounds have been experimentally detected in laboratory experiments. This article reports on calculations carried out using first-principles density functional theory (DFT) on tungsten beryllide crystal (Be12W) taken as a model alloy. The formation and reactivity of atomic vacancies are investigated in the domain of temperature ranging from 0 to 500 K, together with atomic hydrogen retention and diffusivity in the bulk and in/out vacancies.

Evaluation of phytotoxicity of seaport sediments aged artificially by rotary leaching in the framework of a quarry deposit scenario.

In the framework of an ecological risk assessment of seaport sediments for terrestrial ecosystems when deposited in quarries, we simulated the "ageing" of sediments exposed to rain. This experiment highlighted an inflection point at the solid/liquid ratio 1/25, after which the extraction of pollutants increases moderately. The raw sediments studied inhibited the germination of Lolium perenne and Armeria maritima (a halophytic species) seeds. Furthermore, they affected the early development of L.perenne. The same sediments, leached at a ratio of 1/25, presented a reduction of acute (germination) and chronic (growth) phytotoxicity. The bioconcentration factors of the metals studied decreased with the leached sediment, except for Cu which was still clearly identified in root parts. Thus rotary leaching tests and phytotoxicity bioassays can be used to provide an initial assessment of the ability of plants, particularly halophytes, to colonize deposits of dredged seaport sediments.

Experimental and theoretical UV characterizations of acetylacetone and its isomers.

Cryogenic matrix isolation experiments have allowed the measurement of the UV absorption spectra of the high-energy non-chelated isomers of acetylacetone, these isomers being produced by UV irradiation of the stable chelated form. Their identification has been done by coupling selective UV-induced isomerization, infrared spectroscopy, and harmonic vibrational frequency calculations using density functional theory. The relative energies of the chelated and non-chelated forms of acetylacetone in the S0 state have been obtained using density functional theory and coupled-cluster methods. For each isomer of acetylacetone, we have calculated the UV transition energies and dipole oscillator strengths using the excited-state coupled-cluster methods, including EOMCCSD (equation-of-motion coupled-cluster method with singles and doubles) and CR-EOMCCSD(T) (the completely renormalized EOMCC approach with singles, doubles, and non-iterative triples). For dipole-allowed transition energies, there is a very good agreement between experiment and theory. In particular, the CR-EOMCCSD(T) approach explains the blue shift in the electronic spectrum due to the formation of the non-chelated species after the UV irradiation of the chelated form of acetylacetone. Both experiment and CR-EOMCCSD(T) theory identify two among the seven non-chelated forms to be characterized by red-shifted UV transitions relative to the remaining five non-chelated isomers.

Hydrogen adsorption on graphite (0001) surface: a combined spectroscopy-density-functional-theory study.

The adsorption of H/D atoms on the graphite (0001) surface is investigated by means of both high-resolution electron-energy loss spectroscopy (HREELS) and periodic first-principle density-functional theory. The two methods converge towards two modes of adsorption: adsorption in clusters of about four hydrogen atoms and adsorption in pairs of atoms on contiguous carbon sites. The desorption energies estimated from the calculated dissociation energies range from 8 to 185 kJ mol(-1) leading to an estimated surface coverage at saturations of 30-44 at. %. These results are compared with previous thermal desorption spectroscopy results. New HREEL signal assignments are proposed based on quantum calculations.

Electron solvation by highly polar molecules: density functional theory study of atomic sodium interaction with water, ammonia, and methanol.

This study further extends the scope of a previous paper [Y. Ferro and A. Allouche, J. Chem. Phys. 118, 10461 (2003)] on the reactivity of atomic Na with water to some other highly polar molecules known for their solvation properties connected to efficient hydrogen bonding. The solvation mechanisms of ammonia and methanol are compared to the hydration mechanism. It is shown that in the case of ammonia, the stability of the solvated system is only ensured by electrostatic interactions, whereas the methanol action is more similar to that of water. More specific attention is given to the solvation process of the valence 3s Na electron. The consequences on the chemical reactivity are analyzed: Whereas ammonia is nonreactive when interacting with atomic sodium, two chemical reactions are proposed for methanol. The first process is dehydrogenation and yields methoxy species and hydrogen. The other one is dehydration and the final products are methoxy species, but also methyl radical and water. The respective roles of electron solvation and hydrogen bonds network are analyzed in detail in view of the density of states of the reactive systems.

Adsorption, diffusion, and recombination of hydrogen on pure and boron-doped graphite surfaces.

Boron inserted as impurity by substitution of carbon atoms in graphite is known to modify the reactivity of the surface in interaction with hydrogen. Boron induces a better H retention capability in graphite while it makes easier the recombination into molecular hydrogen under heating in thermal-desorption experimental conditions. It has already been calculated that boron modifies the electronic structure of the surface, which results in an increase of the adsorption energy for H. This result seems in good agreement with the better retention for H in doped graphite, but contradictory with the easier recombination observed. The aim of this work is to dismiss this contradiction by elucidating the modifications induced by boron in the recombination mechanism. We studied the diffusion of H on pure and boron-doped graphite in the density functional theory framework. We determined a diffusionlike mechanism leading to molecular hydrogen formation. Finally, we have shown the fundamental modifications induced by boron on the [0001] graphite surface reactivity. From these calculations it stands out that recombination is the result of desorption on pure graphite and diffusion on B-doped surfaces, while the activation energy for the rate limiting step is half reduced by boron. The results are compared to experimental observations. The connection between the cluster and periodic quantum modes for graphite is also discussed.

Electron delocalization by polar molecules: interaction of Na atoms with solid ammonia films studied with MIES and density functional theory.

The interaction of Na and NH(3) on tungsten was studied with metastable impact electron spectroscopy under UHV conditions. NH(3)(Na) films were grown at 90(+/-10) K on tungsten substrates and exposed to Na(NH(3)). No Na-induced reaction involving NH(3) takes place. At small Na exposures a Na-induced shift of the NH(3) spectral features is seen, in parallel with a decrease of the surface work function. At larger exposures three 3sNa-related spectral structures are seen, two of them at energetic positions different from that found for Na on metals or semiconductors. The main additional peak is attributed to delocalized Na species. A small additional feature is attributed to simultaneous ionization and excitation of partially ammoniated Na(2) species. The results are compared with density functional theory calculations which suggest that the 3sNa emission at small exposures appears to originate mainly from delocalized 3sNa electrons; they are located far from the Na species and become stabilized by solvent molecules. When depositing NH(3) molecules onto Na films, metalliclike Na patches and delocalized Na species coexist. The delocalization of 3sNa is seen up to T=130 K where the NH(3) species desorb.

Electron solvation by polar molecules: the interaction of Na atoms with solid methanol films studied with MIES and density functional theory calculations.

The interaction of Na atoms with CH(3)OH films was studied with metastable impact electron spectroscopy (MIES) under UHV conditions. The films were grown at 90(+/-10) K on tungsten substrates and exposed to Na. Na-induced formation of methoxy (CH(3)O) species takes place, and Na atoms become ionized. At small Na exposures the outermost solvent layer remains largely intact as concluded from the absence of MIES signals caused by the reaction products. However, emission from CH(3)O, located at the film surface, occurs at larger exposures. In the same exposure range also Na species can be detected at the surface. The spectral feature from 3s Na ionization occurs at an energetic position different from that found for metals or semiconductors. The results are compared with density functional theory calculations [see Y. Ferro, A. Allouche, and V. Kempter, J. Chem. Phys. 120, 8683 (2004), preceding paper]. Experiment and theory agree in the energetic positions of the main spectral features from the methanol and sodium ionization. The calculations suggest that the 3s Na emission observed experimentally originates from solvated 3s electrons which are located far from the Na core and become stabilized by solvent molecules. The simultaneous emergence of emission from CH(3)O and from solvated 3s electrons suggests that the delocalization and, consequently, the solvation play an important role in the Na-induced formation of CH(3)O from CH(3)OH.