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Graphene has become in last decades a paradigmatic example of two-dimensional and so-called van-der-Waals layered materials, showing large anisotropy in their physical properties. Here, we study the elastic properties and mechanical stability of graphene bilayers in a wide temperature range by molecular dynamics simulations. We concentrate on in-plane elastic constants and compression modulus, as well as on the atomic motion in the out-of-plane direction. Special emphasis is placed upon the influence of anharmonicity of the vibrational modes on the physical properties of bilayer graphene. We consider the excess area appearing in the presence of ripples in graphene sheets at finite temperatures. The in-plane compression modulus of bilayer graphene is found to decrease for rising temperature, and results to be higher than for monolayer graphene. We analyze the mechanical instability of the bilayer caused by an in-plane compressive stress. This defines a spinodal pressure for the metastability limit of the material, which depends on the system size. Finite-size effects are described by power laws for the out-of-plane mean-square fluctuation, compression modulus, and spinodal pressure. Further insight into the significance of our results for bilayer graphene is gained from a comparison with data for monolayer graphene and graphite. [ABSTRACT FROM AUTHOR]

We present an experimental technique using orbital angular momentum (OAM) in a fundamental laser field to drive high harmonic generation (HHG). The mixing of beams with different OAM allows us to generate two laser foci tightly spaced which generate harmonics that interfere in the far field. Thus, this technique is an OAM based in situ HHG interferometric spectroscopic method. With this tool, we measure the phase and amplitude of the angle dependent multiorbital HHG emission in molecular nitrogen. [ABSTRACT FROM AUTHOR]

Graphene bilayers display peculiar electronic and mechanical characteristics associated with their two-dimensional character and relative disposition of the sheets. Here, we study nuclear quantum effects in graphene bilayers by using path-integral molecular dynamics simulations, which allow us to consider quantization of vibrational modes and study the effect of anharmonicity on physical variables. Finite-temperature properties are analyzed in the range from 12 to 2000 K. Our results for graphene bilayers are compared with those found for graphene monolayers and graphite. Nuclear quantum effects turn out to be appreciable in the layer area and interlayer distance at finite temperatures. Differences in the behavior of in-plane and real areas of the graphene sheets are discussed. The interlayer spacing has a zero-point expansion of 1.5 × 10−2 Å with respect to the classical minimum. The compressibility of graphene bilayers in the out-of-plane direction is found to be similar to that of graphite at low temperatures and increases faster as the temperature is raised. The low-temperature compressibility increases by 6% due to zero-point motion. Special emphasis is placed on atomic vibrations in the out-of-plane direction. Quantum effects are present in these vibrational modes, but classical thermal motion becomes dominant over quantum delocalization for large system size. The significance of anharmonicities in this atomic motion is estimated by comparing with a harmonic approximation for the vibrational modes in graphene bilayers. [ABSTRACT FROM AUTHOR]

Path-integral molecular dynamics (PIMD) simulations have been carried out to study the influence of quantum dynamics of carbon atoms on the properties of a single graphene layer. Finite-temperature properties were analyzed in the range from 12 to 2000 K, by using the LCBOPII effective potential. To assess the magnitude of quantum effects in structural and thermodynamic properties of graphene, classical molecular dynamics simulations have been also performed. Particular emphasis has been laid on the atomic vibrations along the out-of-plane direction. Even though quantum effects are present in these vibrational modes, we show that at any finite temperature classical-like motion dominates over quantum delocalization, provided that the system size is large enough. Vibrational modes display an appreciable anharmonicity, as derived from a comparison between kinetic and potential energies of the carbon atoms. Nuclear quantum effects are found to be appreciable in the interatomic distance and layer area at finite temperatures. The thermal expansion coefficient resulting from PIMD simulations vanishes in the zero-temperature limit, in agreement with the third law of thermodynamics. [ABSTRACT FROM AUTHOR]

The configurational entropy of several H-disordered ice polymorphs is calculated by means of a thermodynamic integration along a path between a totally H-disordered state and one fulfilling the Bernal-Fowler ice rules. A Monte Carlo procedure based on a simple energy model is used, so that the employed thermodynamic path drives the system from high temperatures to the low-temperature limit. This method turns out to be precise enough to give reliable values for the configurational entropy sth of different ice phases in the thermodynamic limit (number of molecules N→∞). The precision of the method is checked for the ice model on a two-dimensional square lattice. Results for the configurational entropy are given for H-disordered arrangements on several polymorphs, including ices Ih, Ic, II, III, IV, V, VI, and XII. The highest and lowest entropy values correspond to ices VI and XII, respectively, with a difference of 3.3% between them. The dependence of the entropy on the ice structures has been rationalized by comparing it with structural parameters of the various polymorphs, such as the mean ring size. A particularly good correlation has been found between the configurational entropy and the connective constant derived from self-avoiding walks on the ice networks. [ABSTRACT FROM AUTHOR]

Structural and thermodynamic properties of high-density amorphous (HDA) ice have been studied by path-integral molecular dynamics simulations in the isothermal-isobaric ensemble. Interatomic interactions were modeled by using the effective q-TIP4P/F potential for flexible water. Quantum nuclear motion is found to affect several observable properties of the amorphous solid. At low temperature (T = 50 K) the molar volume of HDA ice is found to increase by 6%, and the intramolecular O-H distance rises by 1.4% due to quantum motion. Peaks in the radial distribution function of HDA ice are broadened with respect to their classical expectancy. The bulk modulus, B, is found to rise linearly with the pressure, with a slope ∂B/∂P = 7.1. Our results are compared with those derived earlier from classical and path-integral simulations of HDA ice. We discuss similarities and discrepancies with those earlier simulations. [ABSTRACT FROM AUTHOR]

Knowledge of the anatomy of the foramen transversarium (FT) is essential for performing surgical procedures on the cervical spine. The aim of the present study was to analyze the characteristics of the FT anatomy of the lower cervical spine and its anatomic variations using computed tomography (CT) in a Brazilian population. Two independent observers performed linear measurements of the anteroposterior diameter (APD), lateral diameter (LD), and FT area (FTA) of 600 FTs of the lower cervical spine of 60 individuals (30 women and 30 men). The CT images were obtained from a database. The data were compared between genders and different age cohorts. The lowest average APD, LD, and FTA were found at the C7 level. The highest mean APD was found at the C6 level, and the highest mean LD was found at the C3 level. The highest mean FTA was at the C3 for the women and C6 for the men. The mean APD, LD, and FTA on the left side were greater than those on the right side at all levels. We found a tendency for the mean FTA to increase with increasing age. Finally, 95% of the whole sample had presented with ≥1 and 42% with >3 anatomical variations of the FT. We determined the morphometric features of the FT using CT images. Anatomic variations were observed that justify their study before performing cervical surgical procedures. [ABSTRACT FROM AUTHOR]

Ice Ih has been studied by path-integral molecular dynamics simulations, using the effective q-TIP4P/F potential model for flexible water. This has allowed us to analyze finite-temperature quantum effects in this solid phase from 25 to 300 K at ambient pressure. Among these effects we find a negative thermal expansion of ice at low temperatures, which does not appear in classical molecular dynamics simulations. The compressibility derived from volume fluctuations gives results in line with experimental data. We have analyzed isotope effects in ice Ih by considering normal, heavy, and tritiated water. In particular, we studied the effect of changing the isotopic mass of hydrogen on the kinetic energy and atomic delocalization in the crystal as well as on structural properties such as interatomic distances and molar volume. For D2O ice Ih at 100 K we obtained a decrease in molar volume and intramolecular O-H distance of 0.6% and 0.4%, respectively, as compared to H2O ice. [ABSTRACT FROM AUTHOR]

Silicon carbide is a hard, semiconducting material presenting many polytypes, whose behavior under extreme conditions of pressure and temperature has attracted large interest. Here we study the mechanical properties of 3 C -SiC over a wide range of pressures (compressive and tensile) by means of molecular dynamics simulations, using an effective tight-binding Hamiltonian to describe the interatomic interactions. The accuracy of this procedure has been checked by comparing results at T = 0 with those derived from ab-initio density-functional-theory calculations. This has allowed us to determine the metastability limits of this material and in particular the spinodal point (where the bulk modulus vanishes) as a function of temperature. At T = 300 K, the spinodal instability appears for a lattice parameter about 20% larger than that corresponding to ambient pressure. At this temperature, we find a spinodal pressure P s = − 43 GPa , which becomes less negative as temperature is raised ( P s = − 37. 9 GPa at 1500 K). These results pave the way for a deeper understanding of the behavior of crystalline semiconductors in a poorly known region of their phase diagrams. [Display omitted] • Cubic SiC is metastable in a large region of tensile pressure up to about 40 GPa. • Attractive region of the interatomic potential is explored for tensile stress. • Spinodal pressure is found as a function of temperature up to 1500 K. • 3C-SiC becomes an auxetic solid for a tensile pressure of 27 GPa. [ABSTRACT FROM AUTHOR]

This paper discusses transformations between bases used in closed-loop learning control experiments. The goal is to transform to a basis in which the number of control parameters is minimized and in which the parameters act independently. We demonstrate a simple procedure for testing whether a unitary linear transformation (i.e., a rotation amongst the control variables) is sufficient to reduce the search problem to a set of globally independent variables. This concept is demonstrated with closed-loop molecular fragmentation experiments utilizing shaped, ultrafast laser pulses. [ABSTRACT FROM AUTHOR]

Two-dimensional (2D) silicon carbide is an emergent direct band-gap semiconductor, recently synthesized, with potential applications in electronic devices and optoelectronics. Here, we study nuclear quantum effects in this 2D material by means of path-integral molecular dynamics (PIMD) simulations in the temperature range from 25 to 1500 K. Interatomic interactions are modeled by a tight-binding Hamiltonian fitted to density-functional calculations. Quantum atomic delocalization combined with anharmonicity of the vibrational modes cause changes in structural and thermal properties of 2D SiC, which we quantify by comparison of PIMD results with those derived from classical molecular dynamics simulations, as well as with those given by a quantum harmonic approximation. Nuclear quantum effects are found to be appreciable in structural properties such as the layer area and interatomic distances. Moreover, we consider a real area for the SiC sheet, which takes into account bending and rippling at finite temperatures. Differences between this area and the in-plane area are discussed in the context of quantum atomic dynamics. The bending constant (κ = 1. 0 eV) and the 2D modulus of hydrostatic compression (B x y = 5.5 eV/Å 2) are clearly lower than the corresponding values for graphene. This study paves the way for a deeper understanding of the elastic and mechanical properties of 2D SiC. [Display omitted] • Nuclear quantum effects are assessed in 2D SiC by path-integral simulations. • Difference between in-plane and real sheet areas is quantified at finite temperatures. • Quantum effects are appreciable in structural properties of SiC sheets. • Comparison with graphene sheds light on relative mechanical strength of 2D SiC. [ABSTRACT FROM AUTHOR]

[Display omitted] • Molecular dynamics simulations shed light on H permeation in defective graphene. • Hydrogen dynamics is highly enhanced in the presence of defects. • Strong correlations appear in the motion of two H atoms. • Successive atomic jumps are uncorrelated for one H atom. The hydrogen dynamics on a graphene sheet is studied in the presence of carbon vacancies. We analyze the motion of atomic H by means of molecular dynamics (MD) simulations, using a tight-binding Hamiltonian fitted to density-functional calculations. Hydrogen passivates the dangling bonds of C atoms close to a vacancy, forming C–H bonds with H located at one or the other side of the layer plane. The hydrogen dynamics has been studied from statistical analysis of MD trajectories, along with the autocorrelation function of the atomic coordinates. For a single H atom, we find an effective barrier of 0.40 eV for crossing the graphene layer, with a jump rate ν = 2 × 10 6 s−1 at 300 K. The atomic jumps behave as stochastic events, and their number for a given temperature and time interval follows a Poisson probability distribution. For two H atoms close to a vacancy, strong correlations in the atomic dynamics are found, with a lower jump frequency ν = 7 × 10 2 s−1 at room temperature. These results provide insight into the diffusion mechanisms of hydrogen on graphene, paving the way for a complete understanding of its motion through defective crystalline membranes. [ABSTRACT FROM AUTHOR]

We report experimental results of femtosecond laser processing on the surface of glass and metal thin film using superposed Bessel beams. These beams are generated by a combination of a spatial light modulator (SLM) and an axicon with >50% efficiency, and they possess the long depth-of-focus (propagation-invariant) property as found in ordinary Bessel beams. Through micromachining experiments using femtosecond laser pulses, we show that multiple craters can be fabricated on glass with single-shot exposure, and the 1+(−1) superposed beam can reduce collateral damage caused by the rings in zero-order Bessel beams in the scribing of metal thin film. [ABSTRACT FROM AUTHOR]

The effects of pressure and temperature on structural and thermodynamic properties of ice VII have been studied by using path-integral molecular dynamics (PIMD) simulations. Temperatures between 25 and 450 K, as well as pressures up to 12 GPa were considered. Interatomic interactions were modeled by using the effective q-TIP4P/F potential for flexible water. We analyze the pressure dependence of the molar volume, bulk modulus, interatomic distances, kinetic energy, and atomic delocalization at various temperatures. Results of PIMD simulations are compared with those derived from a quasi-harmonic approximation (QHA) of vibrational modes, which helps to assess the importance of anharmonic effects, as well as the influence of the different modes on the properties of ice VII. The accuracy of the QHA for describing this high-pressure phase decreases for rising temperature, but this approximation becomes more reliable as pressure grows, since anharmonicity becomes less relevant. Comparisons with low-pressure cubic ice are presented. [ABSTRACT FROM AUTHOR]

Thermal properties of graphene monolayers are studied by path-integral molecular dynamics simulations, which take into account the quantization of vibrational modes in the crystalline membrane and allow one to consider anharmonic effects in these properties. This system was studied at temperatures in the range from 12 to 2000 K and zero external stress, by describing the interatomic interactions through the LCBOPII effective potential. We analyze the internal energy and specific heat and compare the results derived from the simulations with those yielded by a harmonic approximation for the vibrational modes. This approximation turns out to be rather precise up to temperatures of about 400 K. At higher temperatures, we observe an influence of the elastic energy due to the thermal expansion of the graphene sheet. Zero-point and thermal effects on the in-plane and “real” surface of graphene are discussed. The thermal expansion coefficient α of the real area is found to be positive at all temperatures, in contrast to the expansion coefficient α p of the in-plane area, which is negative at low temperatures and becomes positive for T ≳ 1000 K. [ABSTRACT FROM AUTHOR]

The Ising model in clustered scale-free networks has been studied by Monte Carlo simulations. These networks are characterized by a degree distribution of the form P(k) ~ k-γ for large k. Clustering is introduced in the networks by inserting triangles, i.e., triads of connected nodes. The transition from a ferromagnetic (FM) to a paramagnetic (PM) phase has been studied as a function of the exponent γ and the triangle density. For γ>3 our results are in line with earlier simulations, and a phase transition appears at a temperature Tc(γ) in the thermodynamic limit (system size N → ∞). For γ ≤ 3, a FM-PM crossover appears at a size-dependent temperature Tco, so the system remains in a FM state at any finite temperature in the limit N → ∞. Thus, for γ = 3, Tco scales as lnN, whereas for γ<3, we find Tco ~ JNz, where the exponent z decreases for increasing γ. Adding motifs (triangles in our case) to the networks causes an increase in the transition (or crossover) temperature for exponent γ>3 (or ≤ 3). For γ>3, this increase is due to changes in the mean values 〈k〉 and 〈k²〉, i.e., the transition is controlled by the degree distribution (nearest-neighbor connectivities). For γ ≤ 3, however, we find that clustered and unclustered networks with the same size and distribution P(k) have different crossover temperature, i.e., clustering favors FM correlations, thus increasing the temperature Tco. The effect of a degree cutoff kcut on the asymptotic behavior of Tco is discussed. [ABSTRACT FROM AUTHOR]

Topological properties of crystalline ice structures are studied by means of self-avoiding walks on their H-bond networks. The number of self-avoiding walks, C n, for eight ice polymorphs has been obtained by direct enumeration up to walk length n = 27. This has allowed us to determine the 'connective constant' or effective coordination number μ of these structures as the limit of the ratio Cn/Cn-1 for large n. This structure-dependent parameter μ is related with other topological characteristics of ice polymorphs, such as the mean and minimum ring size, or the topological density of network sites. A correlation between the connective constant and the configurational entropy of hydrogen-disordered ice structures is discussed. [ABSTRACT FROM AUTHOR]

Endplate separations are defined as the presence of a space between the hyaline cartilage and the cortical bone of the adjacent vertebral body. This study evaluates endplate separations from the vertebral body and inter-vertebral discs and verifies if endplate separation is related to age and the spinal level. Groups were formed based on age (20-40 and 41-85 years old) and the vertebral segment (T7-T8 and L4-L5 segments).Histological analysis included assessment of the length of the vertebral endplates, the number and dimensions of the separations, and orientation of the collagen fibers, in the mid-sagittal slice. Two indexes were created: the separation index (number of separations/vertebral length) and separation extension index (sum of all separations/vertebral length). The results of the study demonstrated a direct relationship between the density of separations in the endplate and two variables: age and spinal level. [ABSTRACT FROM AUTHOR]

Symptomatic disc calcifications have been reported, especially in the pediatric population, and remain of unknown etiology. Such a condition has been very rarely reported in adults. The aim of this paper is to present a case report of calcific discitis in an adult patient with intravertebral migration and spontaneous calcification resorption. The clinical presentation was that of back pain with an abrupt onset, not related to trauma or to physical activity. No fever or neurological deficits were present. Blood count, erythrocyte sedimentation rate, routine urine, and urine culture were negative. The pain regressed in 20 days with analgesic therapy. Findings of thoracic calcific discitis are illustrated with X-rays, CT, MRI, and bone scintigraphy. [ABSTRACT FROM AUTHOR]

Highlights: [•] Configurational entropy of ice is accurately derived from thermodynamic integration. [•] Entropy associated to proton disorder depends on the considered ice structure. [•] Configurational entropy of proton distribution is larger for ice VI than for ice Ih. [Copyright &y& Elsevier]

The effect of pressure on structural and thermodynamic properties of ice Ih has been studied by means of path-integral molecular dynamics simulations at temperatures between 50 and 300 K. Interatomic interactions were modeled by using the effective q-TIP4P/F potential for flexible water. Positive (compression) and negative (tension) pressures have been considered, which allowed us to approach the limits for the mechanical stability of this solid water phase. We have studied the pressure dependence of the crystal volume, bulk modulus, interatomic distances, atomic delocalization, and kinetic energy. The spinodal point at both negative and positive pressures is derived from the vanishing of the bulk modulus. For P < 0, the spinodal pressure changes from -1.38 to- 0.73 GPa in the range from 50 to 300 K. At positive pressure the spinodal is associated with ice amorphization, and at low temperatures it is found to be between 1.1 and 1.3 GPa. Quantum nuclear effects cause a reduction of the metastability region of ice Ih. [ABSTRACT FROM AUTHOR]

The article presents a study on the isolated and cultured osteoblastic cells found in vertebral lamina and iliac crest of same conditions. The study aims to compare the growth and construction of osteoblastic phenotype of cells derived from vertebral lamina and iliac grafting. It mentions that Trypan blue and direct cell counting were used to evaluate the cells from both vertebral and iliac crest. Result shows that the growth of cells in vertebral lamina is greater than the cells in iliac crest.

Graphane is a layered material consisting of a sheet of hydrogenated graphene, with a C:H ratio of 1:1. We study isotopic effects in the properties of chair graphane, where H atoms alternate in a chairlike arrangement on both sides of the carbon layer. We use path-integral molecular dynamics simulations, which allows one to analyze the influence of nuclear quantum effects on equilibrium variables of materials. Finite-temperature properties of graphane are studied in the range 50–1500 K as functions of the isotopic mass of the constituent atoms, using an efficient tight-bonding potential. Results are presented for kinetic and internal energy, atomic mean-square displacements, fluctuations in the C–H bond direction, plus interatomic distances and layer area. At low temperature, substituting 13C for 12C gives a fractional change of −2.6 × 10−4 in C–C distance and −3.9 × 10−4 in the graphane layer area. Replacing 2H for 1H causes a larger fractional change in the C–H bond of −5.7 × 10−3. The isotopic effect in C–C bond distance increases (decreases) by applying a tensile (compressive) in-plane stress. These results are interpreted in terms of a quasiharmonic approximation for the vibrational modes. Similarities and differences with isotopic effects in graphene are discussed. [Display omitted] • Path-integral simulations allow us to quantify nuclear quantum effects in graphane. • Isotopic effects are appreciable for several properties up to room temperature. • A quasiharmonic approximation is reliable for a large parameter range. [ABSTRACT FROM AUTHOR]

Abstract: Polyphenolic compositions of Basque natural ciders were determined by high-performance liquid chromatography, with diode array detection following thiolysis, in order to differentiate ciders according to the geographical origin of the main raw material used for their elaboration. Fifty percent of the apples used for cidermaking in the Basque Country are imported from France or Galicia (N.W. Spain); this gives beverages of different chemical compositions and sensory qualities. A data set, consisting of 64 cider samples and 33 measured variables, was evaluated using multivariate chemometric techniques. A preliminary study of data structure was performed by cluster analysis and principal component analysis. Different classification systems for the two categories were obtained on the basis of the chemical data by applying several supervised pattern recognition procedures, such as linear discriminant analysis (LDA), K-nearest neighbours (KNN), soft independent modelling of class analogy (SIMCA), and multilayer feed-forward artificial neural networks (MLF-ANN). KNN, SIMCA and the MLF neural network provided complementary results: KNN allowed the correct classification of almost all the ciders of the Galician category, SIMCA provided a model for the ciders of the French category that excluded all ciders made with Galician apples (50% of raw material), and the neural network achieved a level of hits for the classification of the ciders obtained from French apples (50% of raw material) above 95%. Polyphenolic profiles of the ciders provide enough information to develop classification rules for identifying ciders according to the geographical origin of the raw material used for cidermaking. [Copyright &y& Elsevier]

Abstract: Polyphenolic profiles of cider apple cultivars were studied in order to differentiate fruits according to their maturity state (ripe or unripe). Thiolysis and direct solvent extracts of freeze-dried apple pulps and peels were analysed by HPLC-DAD. Univariate data treatment did not achieve the mentioned target; thus a multivariate approach was considered. For each apple tissue data set, several chemometric techniques were applied to the most discriminant variables. Cluster analysis allowed a preliminary study of the data structure. Then, supervised pattern recognition procedures, namely linear discriminant analysis, K-nearest neighbours, soft independent modelling of class analogy, and multilayer feed-forward artificial neural networks (MLF-ANN), were used to develop decision rules to classify samples in the established categories. Excellent results were afforded by MLF-ANN applied to the concentrations of total procyanidins and (+)-catechin and the average degree of polymerisation of procyanidins in apple pulp, with success in the prediction ability of 97% and 99% for unripe and ripe categories, respectively. [Copyright &y& Elsevier]

Isotopic effects are relevant to understand several properties of solids, and have been thoroughly analyzed along the years. These effects may depend on the dimensionality of the considered solid. Here we assess their magnitude for structural properties of graphene, a paradigmatic two-dimensional material. We use path-integral molecular dynamics simulations, a well-suited technique to quantify the influence of nuclear quantum effects on equilibrium variables, especially in cases where anharmonic effects are important. Emphasis is put on interatomic distances and mean-square displacements, as well as on the in-plane area of the graphene layer. At low temperature, the relative difference in C–C distance for 13C and 14C, with respect to 12C, is found to be − 2.5 and − 4.6 × 10−4, respectively, larger than in three-dimensional carbon-based materials such as diamond. For the in-plane area, the relative changes amount to − 3.9 and − 6.9 × 10−4. The magnitude of anharmonicity in the lattice vibrations is estimated by comparing the internal energy and atomic vibrational amplitudes with those derived from a harmonic approximation. [ABSTRACT FROM AUTHOR]

• Path-integral simulations allow us to quantify nuclear quantum effects in graphane. • Quantum effects are noticeable for various magnitudes up to room temperature. • The in-plane area shows marked differences with respect to the classical expectancy. • The compressibility increases by a 9% as compared with a classical calculation. Graphane is a quasi-two-dimensional material consisting of a single layer of fully hydrogenated graphene, with a C:H ratio of 1. We study nuclear quantum effects in the so-called chair-graphane by using path-integral molecular dynamics (PIMD) simulations. The interatomic interactions are modeled by a tight-binding potential model fitted to density-functional calculations. Finite-temperature properties are studied in the range from 50 to 1500 K. To assess the magnitude of nuclear quantum effects in the properties of graphane, classical molecular dynamics simulations have been also performed. These quantum effects are significant in structural properties such as interatomic distances and layer area at finite temperatures. The in-plane compressibility of graphane is found to be about twice larger than that of graphene, and at low temperature it is 9% higher than the classical calculation. The thermal expansion coefficient resulting from PIMD simulations vanishes in the zero-temperature limit, in agreement with the third law of Thermodynamics. [ABSTRACT FROM AUTHOR]

Various types of walks on complex networks have been used in recent years to model search and navigation in several kinds of systems, with particular emphasis on random walks. This gives valuable information on network properties, but self-avoiding walks (SAWs) may be more suitable than unrestricted random walks to study long-distance characteristics of complex systems. Here we study SAWs in clustered scale-free networks, characterized by a degree distribution of the form P(k)∼k-γ for large k. Clustering is introduced in these networks by inserting three-node loops (triangles). The long-distance behavior of SAWs gives us information on asymptotic characteristics of such networks. The number of self-avoiding walks, an, has been obtained by direct enumeration, allowing us to determine the connective constant μ of these networks as the large-n limit of the ratio an/an-1. An analytical approach is presented to account for the results derived from walk enumeration, and both methods give results agreeing with each other. In general, the average number of SAWs an is larger for clustered networks than for unclustered ones with the same degree distribution. The asymptotic limit of the connective constant for large system size N depends on the exponent γ of the degree distribution: For γ>3, μ converges to a finite value as N→∞; for γ=3, the size-dependent μN diverges as lnN, and for γ<3 we have μN∼N(3-γ)/2. [ABSTRACT FROM AUTHOR]

Purpose: To investigate, through a systematic review, the impact of the waiting time for Adolescent Idiopathic Scoliosis (AIS) surgical correction from the point of view of deformity evolution, treatment cost, and quality of life. Methods: PubMed, Embase, LILACS, SciELO, Scopus, Web of Science, LIVIVO, and Cochrane Library databases were searched by two researchers to select the articles. The eligibility criteria were: Patients diagnosed with AIS with indication for surgical correction and submitted to waiting lists until treatment. The risks of bias were evaluated using the Risk Of Bias In Non-randomized Studies—Interventions (ROBINS-I) tool, and the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) system was used to classify the level of the evidence for each outcome. The summary of the available evidence is presented in a narrative synthesis. Results: Six observational studies were included. In a Canadian study, the primary outcome was the need for additional spine surgery in patients who had to wait more than three months due to spine deformity progression. American researchers presented a sample of premenarcheal and skeletally immature patients with AIS showing increased Cobb angle and attributed this to a six-month waiting for the surgical treatment. Another study included 177 patients with AIS with a mean waiting time of 225.7 days. There was a worsening average of 7.7° ± 8.6° in Cobb angle, and there was a change in surgical plan in 28 patients, which increased surgical time. Studies that evaluated the treatment cost showed significantly higher mean costs in those who waited longer than six months. Regarding the quality of life, while waiting for surgery, a retrospective study found that patients who underwent surgery earlier showed better results in a questionnaire that assessed their quality of life compared to those who were still waiting. Conclusion: Observational studies show that, in individuals who are on waiting lists for AIS surgery, there is a worsening of the spinal deformity (substantial evidence), an increasing cost of treatment (moderate evidence) and it may negatively impact patients' quality of life (insufficient evidence). Performing better methodological quality studies to investigate these outcomes can violate good research practices since randomized clinical trials on this subject have ethical limitations to be carried out. Trial registration: The authors declare that the systematic review protocol was registered at the international prospective register of systematic reviews (PROSPERO), CRD42020212134, and it was accepted for publication. [ABSTRACT FROM AUTHOR]

Since their inception, velocity map imaging (VMI) techniques have received continued interest in their expansion from 2D to 3D momentum measurements through either reconstructive or direct methods. Recently, much work has been devoted to the latter of these by relating electron time-of-flight (TOF) to the third momentum component. The challenge is having a timing resolution sufficient to resolve the structure in the narrow (<10 ns) electron TOF spread. Here, we build upon the work in VMI lens design and 3D VMI measurement by using a plano–convex thick-lens (PCTL) VMI in conjunction with an event-driven camera (TPX3CAM) providing TOF information for high resolution 3D electron momentum measurements. We perform simulations to show that, with the addition of a mesh electrode to the thick-lens geometry, the resulting plano–convex electrostatic field extends the detectable electron cutoff energy range while retaining the high resolution. This design also extends the electron TOF range, allowing for a better momentum resolution along this axis. We experimentally demonstrate these capabilities by examining above-threshold ionization in xenon, where the apparatus is shown to collect electrons of energy up to ∼7 eV with a TOF spread of ∼30 ns, both of which are improved compared to a previous work by factors of ∼1.4 and ∼3.75, respectively. Finally, the PCTL-VMI is equipped with a coincident ion TOF spectrometer, which is shown to effectively extract unique 3D momentum distributions for different ionic species in a gas mixture. These techniques have the potential to lend themselves to more advanced measurements involving systems where the electron momentum distributions possess non-trivial symmetries. [ABSTRACT FROM AUTHOR]

Aim. To investigate the relation between malnutrition and nosocomial infections (NI) in hospitalized cancer patients. Methods. This observational, cross-sectional, noninterventional, descriptive study was conducted in a 500-bed university hospital in Valencia (Spain). Adult cancer patients admitted to the oncology ward were consecutively enrolled regardless of their nutritional status between November 2019 and March 2020. Patients were nutritionally assessed 24 to 48 hours after admission. Body weight, height and BMI, body composition through measurement of bioelectrical impedance analysis (BIA), and muscle strength and functionality using hand grip strength (HGS) were prospectively collected. The diagnosis of malnutrition and sarcopenia was assessed using the Global Leadership Initiative on Malnutrition (GLIM) criteria and the European Working Group on Sarcopenia in Older People (EWGSOP) criteria, respectively. Patients were followed up during their hospital stay or outpatient oncology visits to identify possible NI. Results. A total of 107 patients were included in this study (mean age 66 years; 66.4% were men). The most frequent reason for admission was cancer treatment (19.6%), followed by infections (18.7%) and digestive tract symptoms (18.7%). Overall, 77.5% (83/107) of the patients were malnourished at admission according to the GLIM criteria, while 52.3% (56/107) were sarcopenic. Nosocomial infections (NI) were significantly more frequent in malnourished (52.1%; 25/48) and severely malnourished (42.1%; 8/19) patients, compared with well-nourished patients without malnutrition (25%; 10/40; p = 0.035). The mean length of hospital stay was 13.9 days, significantly longer in patients with an NI compared to those without infections (18.6 vs. 10.8 days, p < 0.024). Conclusion. This study evidenced the need to implement a routine protocol for the nutritional assessment and support of cancer patients at risk of malnutrition and sarcopenia to reduce the risk of NI during their hospital stay. [ABSTRACT FROM AUTHOR]

Purpose: To conduct an independent assessment of inter- and intraobserver agreement for the META score as a tool for differentiating osteoporotic vertebral fractures and multiple myeloma vertebral fractures.This is a retrospective observational study. The magnetic resonance imaging analysis was made by two independent spinal surgeons. We designated a Subjective assessment, in which the surgeon should establish a diagnostic classification for each vertebral fracture based on personal experience: secondary to osteoporosis, categorized as a benign vertebral fracture (BVF), or attributed to multiple myeloma, categorized a malign vertebral fracture (MVF). After a 90-day interval, both surgeons repeated the evaluations. For the next step, the observers should establish a diagnosis between BVF and MVF according to the META score system, and both observers repeated the evaluations after a 90-day interval. The intra and interobserver reliability of the Subjective evaluation was studied using the kappa (κ) test. Then, the META evaluations were paralleled using the intraclass correlation coefficient (ICC).A total of 220 patients who had the potential to participate in the study were initially enrolled, but after applying the exclusion criteria, 44 patients were included. Thirty-three patients had BVF, and 12 patients presented MVF. Interobserver agreement for both Subjective evaluations moments (initial and 90-days interval) found a slight agreement for both moments (0.35 and 0.40 respectively). Kappa test for both META evaluations moments (initial and 90-days interval) found a moderate interobserver agreement for both moments (0.54 and 0.48 respectively). It was observed that the ICC calculated for the Initial evaluation using META score was 0.680 and that in the 90-days interval was 0.726, indicating regular to good agreement. Kappa test for intraobserver agreements for the Subjective evaluation presented moderate agreement for both Surgeons. On the other side, Kappa test for intraobserver agreements for the META evaluation presented substantial agreement for both Surgeons. The Intraclass Correlation Coefficient of the META score found presented an almost perfect agreement for both Surgeons.Intra and interobserver agreement for both surgeons were unsatisfactory. The lack of consistent reproducibility by the same observer discourages and disfavors the routine use of the META score in clinical decision making, when potentially cases of multiple myeloma may be present.Methods: To conduct an independent assessment of inter- and intraobserver agreement for the META score as a tool for differentiating osteoporotic vertebral fractures and multiple myeloma vertebral fractures.This is a retrospective observational study. The magnetic resonance imaging analysis was made by two independent spinal surgeons. We designated a Subjective assessment, in which the surgeon should establish a diagnostic classification for each vertebral fracture based on personal experience: secondary to osteoporosis, categorized as a benign vertebral fracture (BVF), or attributed to multiple myeloma, categorized a malign vertebral fracture (MVF). After a 90-day interval, both surgeons repeated the evaluations. For the next step, the observers should establish a diagnosis between BVF and MVF according to the META score system, and both observers repeated the evaluations after a 90-day interval. The intra and interobserver reliability of the Subjective evaluation was studied using the kappa (κ) test. Then, the META evaluations were paralleled using the intraclass correlation coefficient (ICC).A total of 220 patients who had the potential to participate in the study were initially enrolled, but after applying the exclusion criteria, 44 patients were included. Thirty-three patients had BVF, and 12 patients presented MVF. Interobserver agreement for both Subjective evaluations moments (initial and 90-days interval) found a slight agreement for both moments (0.35 and 0.40 respectively). Kappa test for both META evaluations moments (initial and 90-days interval) found a moderate interobserver agreement for both moments (0.54 and 0.48 respectively). It was observed that the ICC calculated for the Initial evaluation using META score was 0.680 and that in the 90-days interval was 0.726, indicating regular to good agreement. Kappa test for intraobserver agreements for the Subjective evaluation presented moderate agreement for both Surgeons. On the other side, Kappa test for intraobserver agreements for the META evaluation presented substantial agreement for both Surgeons. The Intraclass Correlation Coefficient of the META score found presented an almost perfect agreement for both Surgeons.Intra and interobserver agreement for both surgeons were unsatisfactory. The lack of consistent reproducibility by the same observer discourages and disfavors the routine use of the META score in clinical decision making, when potentially cases of multiple myeloma may be present.Results: To conduct an independent assessment of inter- and intraobserver agreement for the META score as a tool for differentiating osteoporotic vertebral fractures and multiple myeloma vertebral fractures.This is a retrospective observational study. The magnetic resonance imaging analysis was made by two independent spinal surgeons. We designated a Subjective assessment, in which the surgeon should establish a diagnostic classification for each vertebral fracture based on personal experience: secondary to osteoporosis, categorized as a benign vertebral fracture (BVF), or attributed to multiple myeloma, categorized a malign vertebral fracture (MVF). After a 90-day interval, both surgeons repeated the evaluations. For the next step, the observers should establish a diagnosis between BVF and MVF according to the META score system, and both observers repeated the evaluations after a 90-day interval. The intra and interobserver reliability of the Subjective evaluation was studied using the kappa (κ) test. Then, the META evaluations were paralleled using the intraclass correlation coefficient (ICC).A total of 220 patients who had the potential to participate in the study were initially enrolled, but after applying the exclusion criteria, 44 patients were included. Thirty-three patients had BVF, and 12 patients presented MVF. Interobserver agreement for both Subjective evaluations moments (initial and 90-days interval) found a slight agreement for both moments (0.35 and 0.40 respectively). Kappa test for both META evaluations moments (initial and 90-days interval) found a moderate interobserver agreement for both moments (0.54 and 0.48 respectively). It was observed that the ICC calculated for the Initial evaluation using META score was 0.680 and that in the 90-days interval was 0.726, indicating regular to good agreement. Kappa test for intraobserver agreements for the Subjective evaluation presented moderate agreement for both Surgeons. On the other side, Kappa test for intraobserver agreements for the META evaluation presented substantial agreement for both Surgeons. The Intraclass Correlation Coefficient of the META score found presented an almost perfect agreement for both Surgeons.Intra and interobserver agreement for both surgeons were unsatisfactory. The lack of consistent reproducibility by the same observer discourages and disfavors the routine use of the META score in clinical decision making, when potentially cases of multiple myeloma may be present.Conclusion: To conduct an independent assessment of inter- and intraobserver agreement for the META score as a tool for differentiating osteoporotic vertebral fractures and multiple myeloma vertebral fractures.This is a retrospective observational study. The magnetic resonance imaging analysis was made by two independent spinal surgeons. We designated a Subjective assessment, in which the surgeon should establish a diagnostic classification for each vertebral fracture based on personal experience: secondary to osteoporosis, categorized as a benign vertebral fracture (BVF), or attributed to multiple myeloma, categorized a malign vertebral fracture (MVF). After a 90-day interval, both surgeons repeated the evaluations. For the next step, the observers should establish a diagnosis between BVF and MVF according to the META score system, and both observers repeated the evaluations after a 90-day interval. The intra and interobserver reliability of the Subjective evaluation was studied using the kappa (κ) test. Then, the META evaluations were paralleled using the intraclass correlation coefficient (ICC).A total of 220 patients who had the potential to participate in the study were initially enrolled, but after applying the exclusion criteria, 44 patients were included. Thirty-three patients had BVF, and 12 patients presented MVF. Interobserver agreement for both Subjective evaluations moments (initial and 90-days interval) found a slight agreement for both moments (0.35 and 0.40 respectively). Kappa test for both META evaluations moments (initial and 90-days interval) found a moderate interobserver agreement for both moments (0.54 and 0.48 respectively). It was observed that the ICC calculated for the Initial evaluation using META score was 0.680 and that in the 90-days interval was 0.726, indicating regular to good agreement. Kappa test for intraobserver agreements for the Subjective evaluation presented moderate agreement for both Surgeons. On the other side, Kappa test for intraobserver agreements for the META evaluation presented substantial agreement for both Surgeons. The Intraclass Correlation Coefficient of the META score found presented an almost perfect agreement for both Surgeons.Intra and interobserver agreement for both surgeons were unsatisfactory. The lack of consistent reproducibility by the same observer discourages and disfavors the routine use of the META score in clinical decision making, when potentially cases of multiple myeloma may be present. [ABSTRACT FROM AUTHOR]

We present a simple approach to characterize the spatial variation of the gain in microchannel plate (MCP) coupled to phosphor detectors using single electron or photon hits. The technique is easy to implement and general enough to be extended to other kinds of detectors. We demonstrate the efficacy of the approach on both laboratory and Monte Carlo generated datasets. Furthermore, we use the approach to measure the variation in gain over time as the MCP is exposed to an increasing number of electrons. [ABSTRACT FROM AUTHOR]

The study of nanomaterials is an active area of research for technological applications as well as fundamental science. A common method for studying properties of isolated nanoparticles is by an in-vacuum particle beam produced via an aerodynamic lens. Despite being common practice, characterization of such beams has proven difficult as light scattering detection techniques fail for particles with sizes beyond the diffraction limit. Here we present a new technique for characterizing such nanoparticle beams using strong field ionization. By focusing an ultrafast, mJ-level laser into the particle beam, a nanoparticle within the laser focus is ionized and easily detected by its ejected electrons. This method grants direct access to the nanoparticle density at the location of the focus, and by scanning the focus through the transverse and longitudinal profiles of the particle beam we attain the 3-dimensional particle density distribution for a cylindrically symmetric beam. Further, we show that strong field ionization is effective in detecting spherical nanoparticles as small as 10 nm in diameter. Additionally, this technique is an effective tool in optimizing the particle beam for specific applications. As an example we show that the particle beam density and width can be manipulated by restricting the gas flow into the aerodynamic lens. [ABSTRACT FROM AUTHOR]

Despite bortezomib dose reduction, seven patients (29%) developed neuropathic toxicity (G1-2), one patient had grade 4 neuropathy (4%), and no grade 3 cases were observed (Table S3). Bortezomib cumulative dose, efficacy, and tolerability with three different bortezomib-melphalan-prednisone regimens in previously untreated myeloma patients ineligible for high-dose therapy. Keywords: bortezomib-melphalan-prednisone; dose intensity reduction; elderly; multiple myeloma EN bortezomib-melphalan-prednisone dose intensity reduction elderly multiple myeloma 532 535 4 05/16/22 20220601 NES 220601 Funding information No funding was received. Velcadito: Low dose of bortezomib with melphalan and prednisone for >=75-year-olds newly diagnosed with multiple myeloma. [Extracted from the article]

Purpose: Magnetic resonance (MR) neurography has been used to evaluate entire nerves and nerve bundles by providing better contrast between the nerves and the surrounding tissues. The purpose of the study was to validate diffusion-weighted MR (DW-MR) neurography in visualizing the lumbar plexus during preoperative planning of lateral transpsoas surgery. Methods: Ninety-four (188 lumbar plexuses) spine patients underwent a DW-MR examination of the lumbar plexus in relation to the L3-4 and L4-5 disc spaces and superior third of the L5 vertebral body. Images were reconstructed in the axial plane using high-resolution Maximum Intensity projection (MIP) overlay templates at the disc space and L3-4 and L4-5 interspaces. 10 and 22 mm MIP templates were chosen to mimic the working zone of standard lateral access retractors. The positions of the L4 nerve root and femoral nerve were analyzed relative to the L4-5 disc in axial and sagittal planes. Third-party radiologists and a senior spine surgeon performed the evaluations, with inter- and intraobserver testing performed. Results: In all subjects, the plexus was successfully mapped. At L3-4, in all but one case, the components of the plexus (except the genitofemoral nerve) were located in the most posterior quadrant (zone IV). The L3 and L4 roots coalesced into the femoral nerve below the L4-5 disc space in all subjects. Side-to-side variation was noted, with the plexus occurring in zone IV in 86.2 % right and only 78.7 % of left sides. At the superior third of L5, the plexus was found in zone III in 27.7 % of right and 36.2 % of left sides; and in zone II in 4.3 % right and 2.1 % left sides. Significant inter- and intraobserver agreement was found. Conclusions: By providing the surgeon with a preoperative roadmap of the lumbar plexus, DW-MR may improve the safety profile of lateral access procedures. [ABSTRACT FROM AUTHOR]

Taking into account that MM progression is the most frequent cause of patient's death, attaining a complete response or even a negative minimal residual disease must be the treatment's goal for patients without comorbidities. On the other hand, progression of MM has been the cause of death of TEMM patients in 62% of the cases, demonstrating patients' better disposition to tolerate new treatments. 1 a Median number of lines of treatment (LOT) for transplant-eligible patients (TEMM), non-transplant eligible with low comorbidities (NTMM CIRS <=8) and patients with high comorbidities (NTMM CIRS >8). b Status of multiple myeloma at death for each group of patients. [Extracted from the article]

We demonstrate three-dimensional velocity map imaging of low energy electrons using a TPX3CAM, where the three-dimensional momentum information [px, py, pz] is encoded in position and timing [x, y, t] of hits on the camera sensor. We make use of the camera sensor for the [x, y] information and a constant fraction discriminator and fast time to digital converter in the camera for the time information. We illustrate the capabilities of our apparatus by presenting above threshold ionization measurements of xenon, which produces well defined structures in the momentum resolved photoelectron yield. [ABSTRACT FROM AUTHOR]

Aim: The aim of this study was to evaluate the technical-tactical behavior of the competitors competing in the 2011 University Taekwondo Championship of Spain. Method: The sample consisted of 30 men and 31 women participating in 45 championship finals and semifinals combats. The variables analyzed were: the score, total number of actions, the type of tactical action, the height, the type of technic and kicking leg. Results/Conclusions: The Mann Whitney U test showed significant differences between men and women in total actions, circular techniques and warnings. The results also showed significant gender differences in circular actions in the flyweight and heavyweight categories, in the linear actions in bantamweight and total score in the lightweight category. Significant differences in total actions, attacking actions, actions to the trunk. performed techniques with right leg and circular techniques were also found in the middleweight division. The technical-tactical behavior of taekwondo competitors was found to differ between gender or gender and weight divisions. Women were found to perform more circular actions to the trunk with the right leg and total actions than men, who received more warnings than women. [ABSTRACT FROM AUTHOR]

In imaging diagnosis, redundant nerve roots of the cauda equina are characterized by the presence of elongated, enlarged and tortuous nerve roots in close relationship with a high-grade lumbar spinal canal stenosis. This is not an independent entity, but it is believed to be a consequence of the chronic compression at the level of the lumbar canal stenosis and thus may be part of the natural history of lumbar spinal stenosis. The present paper is aimed at reviewing the histopathological, electrophysiological and imaging findings, particularly at magnetic resonance imaging, as well as the clinical meaning of this entity. As the current assessment of canal stenosis and root compression is preferably performed by means of magnetic resonance imaging, this is the imaging method by which the condition is identified. The recognition of redundant nerve roots at magnetic resonance imaging is important, particularly to avoid misdiagnosing other conditions such as intradural arteriovenous malformations. The literature approaching the clinical relevance of the presence of redundant nerve roots is controversial. There are articles suggesting that the pathological changes of the nerve roots are irreversible at the moment of diagnosis and therefore neurological symptoms are less likely to improve with surgical decompression, but such concept is not a consensus [ABSTRACT FROM AUTHOR]

Abstract: Ultrasound-assisted extraction (UAE) and direct immersion solid-phase microextraction (DI-SPME) were evaluated for the monoterpenic compounds determination in wine samples. The wine extracts obtained were analyzed by gas chromatography–mass spectrometry (GC–MS). The optimization of the variables affecting UAE and SPME methods was carried out in order to achieve the best extraction efficiency. Both UAE and SPME are quantitative (recoveries in the range 93–97% and 71.8–90.9%, respectively), precise (coefficients of variation below 5.5%), sensitive (limits of detection between 30–39μgL−1 and 11–25μgL−1, respectively) and linear over one order of magnitude. The application of both methods to red wine samples showed that UAE provided higher extraction of monoterpenic compounds than SPME. Although SPME remains an attractive alternative technique due to its speed, low sample volume requirements and solvent free character. [Copyright &y& Elsevier]

Abstract: Total polyphenol contents, estimated by Folin–Ciocalteu method, and CIELab chromatic parameters were determined in Basque and French ciders with the aim of developing a classification system to confirm the authenticity of ciders. A preliminary study of data structure was performed by a multivariate data analysis using chemometric techniques such as cluster analysis and principal component analysis. Supervised pattern recognition methods, such as linear discriminant analysis, K-nearest neighbours (KNN), soft independent modelling of class analogy and multilayer feed-forward artificial neural networks (MLF-ANN), provided classification rules for the two categories based on the experimental data. KNN results for Basque ciders afforded an excellent performance in terms of recognition and prediction abilities (99%), providing a useful tool to detect genuine Basque ciders. Despite KNN and MLF-ANN giving the best results for French ciders, with a success rate of prediction ability around 91%, this would not be acceptable for authentication purposes. [Copyright &y& Elsevier]

Among the interbody fusions, lateral lumbar interbody fusion allows access to the lumbar spine through the major psoas muscle, which offers several advantages to the spine surgeon. However, some of its drawbacks cause surgeons to avoid using it as a daily practice. Therefore, to address some of these challenges, we propose the prone transpsoas technique, differing mainly from the traditional technique on patient position—moving from lateral to prone decubitus, theoretically enhancing the lordosis and impacting the psoas morphology. Twenty-four consecutive patients were invited to have magnetic resonance imaging examinations in 3 different positions (prone, dorsal, lateral). Two observers measured the following parameters: vertebral body size, psoas diameter, psoas anterior border distance, plexus distance, total lumbar lordosis, distal lumbar lordosis, and proximal lumbar lordosis. Values of P < 0.05 were deemed significant. The prone position yielded a significant increase in the lumbar lordosis, both in L1-S1 (57° vs. 46.5°) and proximal lordosis (40.4° vs. 36.9°) compared with the lateral position. Regarding the morphologic aspects, patients in the prone position presented lesser psoas muscles forward shift, but no difference was noted in the plexus position neither for L3-L4 nor L4-L5. The prone position resulted in a significantly increased lumbar lordosis, both distal and proximal, which may enable the spine surgeon to achieve significant sagittal restoration just by positioning. The prone position also produced a posterior retraction of the psoas muscle. However, it did not significantly affect the position of the plexus concerning the vertebral body. [ABSTRACT FROM AUTHOR]

A simple technique is described for the routine capillary electrophoretic determination of formic and acetic acid in rain water. These acids were determined simultaneously in approximately 6 min using a carrier electrolyte containing 10 mM phosphate and 0.5 mM myristyltrimethylammonium bromide (MTAB) as electroosmotic flow (EOF) modifier at pH 6.5 and direct UV detection at 185 nm. The method is quantitative, with recoveries in the 99-101% range and linear up to 5 mg L -1 . The precision is better than 2.1% and the procedure shows the appropriate sensitivity, with detection limits between 0.042 and 0.055 mg L -1 . The proposed method was successfully employed for the determination of formic and acetic acid in 57 rain water samples, collected from October 2000 to February 2001 in four different sampling stations located in Galicia (NW Spain), by direct sample injection after filtration. [ABSTRACT FROM AUTHOR]

During a I year period, measurements of carboxylic acids and aldehydes were carried out in rainwater samples collected at nine different sites in NW Spain surrounding a thermal power plant in order to determine concentration levels and sources. In addition, certain major ions (Cl[sup -], NO[sup- , sub 3], SO[sup 2-, sub 4] , Na[sup +], NH[sup +, sub 4], K[sup +], Mg[sup 2+], Ca[sup 2+]) were also determined. Aldehyde and carboxylic acid concentration patterns and their effects on rainwater composition concerning temporal, seasonal and spatial variations were evaluated. Among carboxylic acids, formic and acetic were predominant (VWA 7.0 and 8.3 µM), while formaldehyde and acroleine were the dominant aldehydes (VWA 0.42 and 1.25 µM). Carboxylic acids were estimated to account for 27.5% of the total free acidity (TFA), whereas sulphuric and nitric acid accounted for 46.2% and 26.2%, respectively. Oxalic acid was demonstrated to be an important contributing compound to the acidification in rainwater representing 7.1% of the TFA. The concentration of aldehydes and carboxylic acids, which originated mainly from biogenic emissions in the area studied, was strongly dependent on the season of the year (growing and non-growing). The ratios of formic to acetic acids are considerably different in the two seasons suggesting that there exist distinct sources in both growing and non-growing seasons. Principal component analysis was applied in order to elucidate the sources of aldehydes and organic acids in rainwater. The prevalence of natural vegetative origins for both of these compounds versus anthropogenic emissions was demonstrated and the importance of the oxidation of aldehydes as a relevant source of organic acids was also established. [ABSTRACT FROM AUTHOR]

Incubation of bovine adrenal chromaffin cells in high K+ (38 mM) during 24-48 h enhanced 2.5 to five times the expression of SNAP-25 protein and mRNA, respectively. This increase was reduced 86% by furnidipine (an L-type Ca2+ channel blocker) but was unaffected by either ω-conotoxin GVIA (an N-type Ca2+ channel blocker) or ω-agatoxin IVA (a P/Q-type Ca2+ channel blocker). Combined blockade of N and P/Q channels with ω-conotoxin MVIIC did, however, block by 76% the protein expression. The inhibitory effects of furnidipine were partially reversed when the external Ca2+ concentration was raised from 1.6 to 5 mM. These findings, together with the fact that nicotinic receptor activation or Ca2+ release from internal stores also enhanced SNAP-25 protein expression, suggest that an increment of cytosolic Ca2+ concentration ([Ca2+]i), rather than its source or Ca2+ entry pathway, is the critical signal to induce the protein expression. The greater coupling between L-type Ca2+ channels and protein expression might be due to two facts: (a) L channels contributed 50% to the global [Ca2+]i rise induced by 38 mM K+ in indo-1-loaded chromaffin cells and (b) L channels undergo less inactivation than N or P/Q channels on sustained stimulation of these cells. [ABSTRACT FROM AUTHOR]

Primary plasma cell leukaemia presenting with flower-shaped nuclei On admission, a full blood count showed a haemoglobin concentration of 120 g/l, a platelet count of 98 × 10 SP 9 sp /l and a leukocyte count of 44 × 10 SP 9 sp /l. A peripheral blood film showed 80% atypical lymphoid cells. Plasma cell leukaemia rarely presents with flower-shaped nuclei. [Extracted from the article]

Sagittal balance describes the optimal alignment of the spine in the sagittal plane, resulting from the interaction between the spine and lower limbs, via the pelvis. Understanding sagittal balance has gained importance, especially in the last decade, because sagittal imbalance correlates directly with disability and pain. Diseases that alter that balance cause sagittal malalignment and may trigger compensatory mechanisms. Certain radiographic parameters have been shown to be clinically relevant and to correlate with clinical scores in the evaluation of spinopelvic alignment. This article aims to provide a comprehensive review of the literature on the spinopelvic parameters that are most relevant in clinical practice, as well as to describe compensatory mechanisms of the pelvis and lower limbs. [ABSTRACT FROM AUTHOR]