Bone mineral density in adults with Down syndrome: a cross-sectional study in a Brazilian sample.

BACKGROUND: We aim to investigate the relationship between bone mass in a sample of Brazilian individuals with DS and handgrip strength, body mass index (BMI) and physical exercise. METHODS: Dual-energy X-ray emission densitometry analysis of bone mass in 26 individuals with DS (8 men and 18 women with a mean age of 30.7 ± 10.3 years) was conducted. Additionally, weight and height were measured to determine BMI, palmar grip strength was measured using a Jammar dynamometer®, and physical activity was classified using the International Physical Activity Questionnaire (IPAQ). RESULTS: In this sample, 2/15 (13.3%) individuals with age between 18 to 29 years had low BMD in the spine; 2/8 (25%) of those with age between 30 and 39 years also had low BMD in the spine and 2/3 (66.6%) with age ≥40 had low BMD in the femur. There were significant correlations between palmar grip strength and Z femoral neck score in women (P = 0.02) and between BMI and Z femoral neck score in men (P = 0.04). All other correlations lacked statistical significance (P > 0.05). CONCLUSIONS: Brazilian patients with DS showed a high prevalence of low bone mass. Traditional factors such as muscle strength, BMI and physical activity appear to have little effect on bone mineral density in this population.

The spin-forbidden vacuum-ultraviolet absorption spectrum of 14N15N.

Photoabsorption spectra of 14N15N were recorded at high resolution with a vacuum-ultraviolet Fourier-transform spectrometer fed by synchrotron radiation in the range of 81-100 nm. The combination of high column density (3 × 1017 cm-2) and low temperature (98 K) allowed for the recording of weak spin-forbidden absorption bands' exciting levels of triplet character. The triplet states borrow intensity from 1Πu states of Rydberg and valence character while causing their predissociation. New predissociation linewidths and molecular constants are obtained for the states C3Πu(v = 7, 8, 14, 15, 16, 21), G3Πu(v = 0, 1, 4), and F3Πu(v = 0). The positions and widths of these levels are shown to be well-predicted by a coupled-Schrödinger equation model with empirical parameters based on experimental data on 14N2 and 15N2 triplet levels.

Quantifying the photoionization cross section of the hydroxyl radical.

The hydroxyl free radical, OH, is one of the most important radicals in atmospheric and interstellar chemistry, and its cation plays a role in the reactions leading to H2O formation. Knowledge of the photoionization efficiency of the OH radical is crucial to properly model the water photochemical cycle of atmospheres and astrophysical objects. Using a gas-phase radical source based on a single H-abstraction reaction combined with a photoelectron/photoion imaging coincidence spectrometer coupled with synchrotron radiation, we recorded the OH+ photoion yield over the 12.6-15 eV energy range, and we set it to an absolute cross section scale using an absolute point measurement performed at 13.8 eV: σOH ion=9.0±2.7 Mb. The resulting cross section values differ by approximately a factor 2 from the recent measurement of Dodson et al. [J. Chem. Phys. 148, 184302 (2018)] performed with a different radical source, which is somewhat greater than the combined uncertainties of the measurements. This finding underlines the need for further investigations of this cross section.

Fourier-transform-spectroscopic photoabsorption cross sections and oscillator strengths for the S2 BΣu-3-XΣg-3 system.

Photoabsorption cross sections and oscillator strengths for the strong, predissociating vibrational bands, v ≥ 11, in the S2 BΣu-3-XΣg-3(v,0) system are reported. Absorption measurements were undertaken on S2 vapor produced by a radio-frequency discharge through H2S seeded in helium, and also in a two-temperature sulfur furnace, at temperatures of 370 K and 823 K, respectively. S2 column densities were determined in each source by combining experimental line strengths in low-v non-predissociating B - X bands (v < 7) with calculated line f-values based on measured radiative lifetimes and calculated branching ratios. The broad-band capabilities of two vacuum-ultraviolet Fourier-transform spectrometers, used with instrumental resolutions of 0.22 cm-1 and 0.12 cm-1, respectively, allowed for simultaneous recordings of both non-predissociating and predissociating bands, thus placing the predissociating-band cross sections on a common absolute scale. Uncertainties in the final cross section datasets are estimated to be 15% for the 370-K vapor and 10% for the 823-K vapor. The experimental cross sections are used to inform a detailed predissociation model of the B(v) levels in Paper II [Lewis et al., J. Chem. Phys. 148, 244303 (2018)]. For astrophysical and other applications, this model can be adjusted simply to provide isotopologue-specific cross sections for a range of relevant temperatures.

The antimicrobial peptide aureocin A53 as an alternative agent for biopreservation of dairy products.

AIMS: The aim of this study was to investigate the potential of aureocin A53, a staphylococcal antimicrobial peptide, for improving food safety. METHODS AND RESULTS: The antimicrobial activity of aureocin A53 against strains of Listeria monocytogenes isolated from food was tested and the bacteriocin proved to be bactericidal and bacteriolytic against the listerial strains. Aureocin A53 was neither toxic to eukaryotic cell lines nor haemolytic against sheep erythrocytes. It also exhibited a remarkable stability during storage at different temperatures and sensitivity to both simulated gastric juice and bile salts. When the antibacterial activity of aureocin A53 (256 AU ml(-1) ) was tested in skimmed milk artificially inoculated with a L. monocytogenes strain (1·0 × 10(4)  CFU ml(-1) ) isolated from food, during storage at 4°C, the bacteriocin reduced the viable counts by 7·7-log10 units up to 7 days of incubation, when compared with the controls not treated with the bacteriocin. CONCLUSIONS: Aureocin A53 exhibited several features considered important for biopreservation and remained fully active in a food matrix. SIGNIFICANCE AND IMPACT OF THE STUDY: Taken together, the results confirmed that aureocin A53 has potential to be used as a food preservative, representing an alternative to the use of nisin in biopreservation of dairy products.

Who runs the fastest? Anthropometric and physiological correlates of 20 m sprint performance in male soccer players.

The aim of the present study was to examine the relationship of 20 m sprint performance with anthropometrical and physiological parameters in male soccer players. A hundred and 81 soccer players from the region of Athens (age 23.4 ± 5.0 yrs, body mass 73.4 ± 7.7 kg, height 180.0 ± 5.9 cm, body fat (BF) 14.4 ± 3.6%), classified into quartiles according to 20 m sprint time (group A, 2.84-3.03 s; group B, 3.04-3.09 s; group C, 3.10-3.18 s; group D, 3.19-3.61 s), participated. Soccer players in group A were younger and had better performance in vertical jumps and in the Wingate anaerobic test (WAnT, p < 0.05). Sprint time correlated to age (r = 0.27), body mass (r = 0.23), body height (r = 0.20), BF (r = 0.23), vertical jumps (-0.58 ≤ r ≤ -0.50) and the WAnT (-0.45 ≤ r ≤ -0.30, p < 0.05). In summary, the magnitude of correlations of sprint time with measures of lower limbs muscle strength and power (WAnT and jumps) was larger than with anthropometric measures (body mass and BF).

A Near-Threshold Shape Resonance in the Valence-Shell Photoabsorption of Linear Alkynes.

The room-temperature photoabsorption spectra of a number of linear alkynes with internal triple bonds (e.g., 2-butyne, 2-pentyne, and 2- and 3-hexyne) show similar resonances just above the lowest ionization threshold of the neutral molecules. These features result in a substantial enhancement of the photoabsorption cross sections relative to the cross sections of alkynes with terminal triple bonds (e.g., propyne, 1-butyne, 1-pentyne, ...). Based on earlier work on 2-butyne [ Xu et al., J. Chem. Phys. 2012, 136, 154303 ], these features are assigned to excitation from the neutral highest occupied molecular orbital (HOMO) to a shape resonance with g (l = 4) character and approximate π symmetry. This generic behavior results from the similarity of the HOMOs in all internal alkynes, as well as the similarity of the corresponding gπ virtual orbital in the continuum. Theoretical calculations of the absorption spectrum above the ionization threshold for the 2- and 3-alkynes show the presence of a shape resonance when the coupling between the two degenerate or nearly degenerate π channels is included, with a dominant contribution from l = 4. These calculations thus confirm the qualitative arguments for the importance of the l = 4 continuum near threshold for internal alkynes, which should also apply to other linear internal alkynes and alkynyl radicals. The 1-alkynes do not have such high partial waves present in the shape resonance. The lower l partial waves in these systems are consistent with the broader features observed in the corresponding spectra.

High-resolution vacuum-ultraviolet photoabsorption spectra of 1-butyne and 2-butyne.

The absolute photoabsorption cross sections of 1- and 2-butyne have been recorded at high resolution by using the vacuum-ultraviolet Fourier-Transform spectrometer at the SOLEIL Synchrotron. Both spectra show more resolved structure than previously observed, especially in the case of 2-butyne. In this work, we assess the potential importance of Rydberg states with higher values of orbital angular momentum, l, than are typically observed in photoabsorption experiments from ground state molecules. We show how the character of the highest occupied molecular orbitals in 1- and 2-butyne suggests the potential importance of transitions to such high-l (l = 3 and 4) Rydberg states. Furthermore, we use theoretical calculations of the partial wave composition of the absorption cross section just above the ionization threshold and the principle of continuity of oscillator strength through an ionization threshold to support this conclusion. The new absolute photoabsorption cross sections are discussed in light of these arguments, and the results are consistent with the expectations. This type of argument should be valuable for assessing the potential importance of different Rydberg series when sufficiently accurate direct quantum chemical calculations are difficult, for example, in the n ≥ 5 manifolds of excited states of larger molecules.

Excited electronic states of thiophene: high resolution photoabsorption Fourier transform spectroscopy and ab initio calculations.

The recently introduced synchrotron radiation-based Fourier transform spectroscopy has been employed to study the excited electronic states of thiophene. A highly resolved photoabsorption spectrum has been measured between ∼5 and 12.5 eV, providing a wealth of new data. High-level ab initio computations have been performed using the second-order algebraic-diagrammatic construction (ADC(2)) polarization propagator approach, and the equation-of-motion coupled-cluster (EOM-CC) method at the CCSD and CC3 levels, to guide the assignment of the spectrum. The adiabatic energy corrections have been evaluated, thereby extending the theoretical study beyond the vertical excitation picture and leading to a significantly improved understanding of the spectrum. The low-lying π→π* and π→σ* transitions result in prominent broad absorption bands. Two strong Rydberg series converging onto the X(~)(2)A2 state limit have been assigned to the 1a2→npb1(1)B2 and the 1a2→nda2(1)A1 transitions. A second, and much weaker, d-type series has been assigned to the 1a2→ndb1(1)B2 transitions. Excitation into some of the Rydberg states belonging to the two strong series gives rise to vibrational structure, most of which has been interpreted in terms of excitations of the totally symmetric ν4 and ν8 modes. One Rydberg series, assigned to the 3b1→nsa1(1)B1 transitions, has been identified converging onto the Ã(2)B1 state limit, and at higher energies Rydberg states converging onto the B(~)(2)A1 state limit could be identified. The present spectra reveal highly irregular vibrational structure in certain low energy absorption bands, and thus provide a new source of information for the rapidly developing studies of excited state non-adiabatic dynamics and photochemistry.

High-resolution photoabsorption spectrum of jet-cooled propyne.

The absolute photoabsorption cross section of propyne was recorded between 62,000 and 88,000 cm(-1) by using the vacuum-ultraviolet, Fourier-transform spectrometer at the Synchrotron Soleil. This cross section spans the region including the lowest Rydberg bands and extends above the Franck-Condon envelope for ionization to the ground electronic state of the propyne cation, X̃(+). Room-temperature spectra were recorded in a flowing cell at 0.9 cm(-1) resolution, and jet-cooled spectra were recorded at 1.8 cm(-1) resolution and a rotational temperature of ~100 K. The reduced widths of the rotational band envelopes in the latter spectra reveal new structure and simplify a number of assignments. Although nf Rydberg series have not been assigned previously in the photoabsorption spectrum of propyne, arguments are presented for their potential importance, and the assignment of one nf series is proposed. As expected from previous photoelectron spectra, Rydberg series are also observed above the adiabatic ionization threshold that converge to the v3(+) = 1 and 2 levels of the C≡C stretching vibration.

Observation of a new electronic state of CO perturbing W ¹Π(v=1).

We observe photoabsorption of the W(1) ← X(0) band in five carbon monoxide isotopologues with a vacuum-ultraviolet Fourier-transform spectrometer and a synchrotron radiation source. We deduce transition energies, integrated cross sections, and natural linewidths of the observed rotational transitions and find a perturbation affecting these. Following a deperturbation analysis of all five isotopologues, the perturbing state is assigned to the v = 0 level of a previously unobserved (1)Π state predicted by ab initio calculations to occur with the correct symmetry and equilibrium internuclear distance. We label this new state E″ (1)Π. Both of the interacting levels W(1) and E″(0) are predissociated, leading to dramatic interference effects in their corresponding linewidths.

FT-spectroscopy of the 12C18O rare isotopologue and deperturbation analysis of the A1Π(v = 3) level.

Research on 12C18O was carried out using two complementary Fourier-transform methods: (1) vacuum-ultraviolet absorption spectroscopy, with an accuracy ca. 0.03 cm-1 on the DESIRS beamline (SOLEIL synchrotron) and (2) visible emission spectroscopy with an accuracy of about 0.005-0.007 cm-1 by means of the Bruker IFS 125HR spectrometer (University of Rzeszów). The maximum rotational quantum number of the energy levels involved in the observed spectral lines was Jmax = 54. An effective Hamiltonian and the term-value fitting approach were implemented for the precise analysis of the A1Π(v = 3) level in 12C18O. It was performed by means of the PGOPHER code. The data set consisted of 571 spectral lines belonging to the A1Π-X1Σ+(3, 0), B1Σ+-A1Π(0, 3), C1Σ+-A1Π(0, 3) bands and several lines involving states that perturb the A1Π(v = 3) level as well as to the previously analysed B1Σ+-X1Σ+(0, 0) and C1Σ+-X1Σ+(0, 0) transitions. A significantly extended quantum-mechanical description of the A1Π(v = 3) level in 12C18O was provided. It consists of the 5 new unimolecular interactions of the spin-orbit and rotation-electronic nature, which had not been taken into account previously in the literature. The ro-vibronic term values of the A1Π(v = 3, Jmax = 55), a'3Σ+(v = 13), D1Δ(v = 4) and I1Σ-(v = 5) levels were determined with precision improved by a factor of 10 relative to the previously known values.

High-resolution Fourier-transform extreme ultraviolet photoabsorption spectroscopy of 14N15N.

The first comprehensive high-resolution photoabsorption spectrum of (14)N(15)N has been recorded using the Fourier-transform spectrometer attached to the Desirs beamline at the Soleil synchrotron. Observations are made in the extreme ultraviolet and span 100 000-109 000 cm(-1) (100-91.7 nm). The observed absorption lines have been assigned to 25 bands and reduced to a set of transition energies, f values, and linewidths. This analysis has verified the predictions of a theoretical model of N(2) that simulates its photoabsorption and photodissociation cross section by solution of an isotopomer independent formulation of the coupled-channel Schrödinger equation. The mass dependence of predissociation linewidths and oscillator strengths is clearly evident and many local perturbations of transition energies, strengths, and widths within individual rotational series have been observed.

Pathogenicity for onion and genetic diversity of isolates of the pathogenic fungus Colletotrichum gloeosporioides (Phyllachoraceae) from the State of Pernambuco, Brazil.

Onion anthracnose, caused by Colletotrichum gloeosporioides, is one of the main diseases of onions in the State of Pernambuco. We examined the pathogenicity of 15 C. gloeosporioides strains and analyzed their genetic variability using RAPDs and internal transcribed spacers (ITS) of the rDNA region. Ten of the strains were obtained from substrates and hosts other than onion, including chayote (Sechium edule), guava (Psidium guajava), pomegranate (Punica granatum), water from the Capibaribe River, maracock (Passiflora sp), coconut (Cocus nucifera), surinam cherry (Eugenia uniflora), and marine soil; five isolates came from onions collected from four different regions of the State of Pernambuco and one region of the State of Amazonas. Pathogenicity tests were carried out using onion leaves and bulbs. All strains were capable of causing disease in leaves, causing a variable degree of lesions on the leaves; four strains caused the most severe damage. In the onion bulb tests, only three of the above strains caused lesions. Seven primers of arbitrary sequences were used in the RAPD analysis, generating polymorphic bands that allowed the separation of the strains into three distinct groups. The amplification products generated with the primers ITS1 and ITS4 also showed polymorphism when digested with three restriction enzymes, DraI, HaeIII and MspI. Only the latter two demonstrated genetic variations among the strains. These two types of molecular markers were able to differentiate the strain from the State of Amazonas from those of the State of Pernambuco. However, there was no relationship between groups of strains, based on molecular markers, and degree of pathogenicity for onion leaves and bulbs.

Clinical Evaluation of Lithium Disilicate Veneers Manufactured by CAD/CAM Compared with Heat-pressed Methods: Randomized Controlled Clinical Trial.

CLINICAL RELEVANCE: Lithium disilicate veneers for esthetic restorations show great accuracy and similarity, regardless of the type of fabrication technique.

Synchrotron vacuum ultraviolet radiation studies of the D (1)Π(u) state of H(2).

The 3pπD (1)Π(u) state of the H(2) molecule was reinvestigated with different techniques at two synchrotron installations. The Fourier transform spectrometer in the vacuum ultraviolet wavelength range of the DESIRS beamline at the SOLEIL synchrotron was used for recording absorption spectra of the D (1)Π(u) state at high resolution and high absolute accuracy, limited only by the Doppler contribution at 100 K. From these measurements, line positions were extracted, in particular, for the narrow resonances involving (1)Π(u) (-) states, with an accuracy estimated at 0.06 cm(-1). The new data also closely match multichannel quantum defect calculations performed for the Π(-) components observed via the narrow Q-lines. The Λ-doubling in the D (1)Π(u) state was determined up to v=17. The 10 m normal incidence scanning monochromator at the beamline U125/2 of the BESSY II synchrotron, combined with a home-built target chamber and equipped with a variety of detectors, was used to unravel information on ionization, dissociation, and intramolecular fluorescence decay for the D (1)Π(u) vibrational series. The combined results yield accurate information on the characteristic Beutler-Fano profiles associated with the strongly predissociated Π(u) (+) parity components of the D (1)Π(u) levels. Values for the parameters describing the predissociation width as well as the Fano-q line shape parameters for the J=1 and J=2 rotational states were determined for the sequence of vibrational quantum numbers up to v=17.

Understanding the inverse magnetocaloric effect in antiferro- and ferrimagnetic arrangements.

The inverse magnetocaloric effect occurs when a magnetic material cools down under applied magnetic field in an adiabatic process. Although the existence of the inverse magnetocaloric effect was recently reported experimentally, a theoretical microscopic description is almost nonexistent. In this paper we theoretically describe the inverse magnetocaloric effect in antiferro- and ferrimagnetic systems. The inverse magnetocaloric effects were systematically investigated as a function of the model parameters. The influence of the Néel and the compensation temperature on the magnetocaloric effect is also analyzed using a microscopic model.