Entangling non planar molecules via inversion doublet transition with negligible spontaneous emission.

We analyze theoretically the entanglement between two non-planar and light identical molecules (e.g., pyramidal NH3) that present inversion doubling due to the internal spatial inversion of their nuclear conformations by tunneling. The peculiarity of this system lies in the simplicity of this type of molecular system in which two near levels can be connected by an allowed electric dipole transition with considerable value of the dipole moment transition and negligible spontaneous emission because the transition is in the microwave or far-infrared range. These properties give place to entanglement states oscillating by free evolution with frequency determined by the dipole-dipole interaction and negligible spontaneous decay, which allows consideration of an efficient quantum Zeno effect by frequent measurements of one of the entangled states. If the molecules are initially both in the upper (or lower) eigenstate, the system evolves under an external radiation field, which can induce oscillations of the generated entangled states, with frequency of the order of the Rabi frequency of the field. For a certain detuning, a symmetric entangled state, which is an eigenstate of the collective system, can be populated, and given its negligible spontaneous emission, could be maintained for a time limited only by external decoherence processes, which could be minimized. Although the data used are those of the NH3 molecule, other molecules could present the same advantageous features.

Lorenz curve of a light beam: evaluating beam quality from a majorization perspective.

We introduce a novel approach for the characterization of the quality of a laser beam that is not based on particular criteria for beam width definition. The Lorenz curve of a light beam is a sophisticated version of the so-called power-in-the-bucket curve, formed by the partial sums of discretized joint intensity distribution in the near and far fields, sorted in decreasing order. According to majorization theory, a higher Lorenz curve implies that all measures of spreading in phase space, and, in particular, all Rényi (and Shannon) entropy-based measures of the beam width products in near and far fields, are unanimously smaller, providing a strong assessment of a better beam quality. Two beams whose Lorenz curves intersect can be considered of relatively better or lower quality only according to specific criteria, which can be inferred from the plot of the respective Lorenz curves.

Optical rotation of a uniformly, linearly polarized Bessel-like beam in free space.

We report on the observation of a light beam in air whose polarization state is uniform and linear at the transverse region where the intensity is high and rotates uniformly with propagation distance. The beam is obtained by interference of two circularly polarized Bessel beams of opposite helicities and very similar, but not equal, cone angles. The measured rotation rate is in agreement with that expected from theory.

Majorization applied to diffraction.

We apply the statistical tools of majorization to characterize and compare the amount of diffraction caused by different apertures, where variance cannot be applied.

Stabilization of chiral molecules by decoherence and environment interactions in the gas phase.

We study the tunnel dynamics of a chiral molecule between its left (L) and right (R) conformations, under the global effect of collisional decoherence together with the effect of a mean-field generated by the environment where an energetic difference, K, between homochiral and heterochiral interactions is assumed. We show that this decoherence leads unavoidably to equal populations of the L and R chiral conformations even for a high enough value of K which tends to keep localized an initial chiral state. However, we also show that K contributes to the stabilization of an initial L or R state for times that could be many orders of magnitude larger than the tunneling time, in the case the decoherence rate is much greater than the tunneling rate. In this case, an estimation of this stabilization time and a critical tunneling time is made. Even in the case in which the tunneling rate is greater than the decoherence rate, the effect of K is to keep localized the initial chiral state for times greater than the tunneling time. A possible slight chiral asymmetry is also considered.

An alternative route to detect parity violating energy differences through Bose-Einstein condensation of chiral molecules.

Interactions which do not conserve parity might influence chiral compounds giving rise to a parity violating energy difference (PVED) that might have affected the evolution towards homochirality. However, this tiny effect predicted by electroweak-quantum chemistry calculations is easily masked by thermal effects, making it desirable to reach cold regimes in the laboratory. As an alternative route to the detection of the PVED, we study a simplified model of Bose-Einstein condensation of a sample of non-interacting chiral molecules, showing that it leads to a nonzero optical activity of the condensate and also to a subcritical temperature in the heat capacity, due to the internal structure of the molecule characterized by tunneling and parity violation. This predicted singular behavior found for the specific heat, below the condensation temperature, might shed some light on the existence of the thus far elusive PVED between enantiomers.

Quantum stochastic resonance in parity violating chiral molecules.

In order to explore parity violating effects in chiral molecules, of interest in some models of evolution towards homochirality, quantum stochastic resonance (QSR) is studied for the population difference between the two enantiomers of a chiral molecule (hence for the optical activity of the sample), under low viscous friction and in the deep quantum regime. The molecule is described by a two-state model in an asymmetric double well potential where the asymmetry is given by the known predicted parity violating energy difference (PVED) between enantiomers. In the linear response to an external driving field that lowers and rises alternatively each one of the minima of the well, a signal of QSR is predicted only in the case that the PVED is different from zero, the resonance condition being independent on tunneling between the two enantiomers. It is shown that, at resonance, the fluctuations of the first order contribution to the internal energy are zero. Due to the small value of the PVED, the resonance would occur in the ultracold regime. Some proposals concerning the external driving field are suggested.

¿Ha mejorado la dotación de vitamina D3 en España? Actuales niveles en una muestra de la población / Has vitamin D3 dosage improved in Spain? Current levels in a population sample

IntroducciónSegún las clasificaciones actuales, el metabolito de mayor interés clínico para valorar la dotación de vitamina D3 es el 25-hidroxivitamina D3 con un intervalo de referencia en 10–70ng/ml, aunque muchos autores consideran como deseable valores por sobre 40ng/ml o 100nmol/l. Según estas definiciones, en España tres de cada cuatro personas tendrían carencias de vitamina D3.Material y métodoSe ha utilizado una técnica radioinmunoensayo-CT para el diagnóstico de la 25hidroxivitamina D3 para ver el estatus en la población. Posteriormente, se ha realizado un estudio de casos y controles para conocer la relación entre diferentes enfermedades y carencias de vitamina D3.ResultadosEl 73,2% de los casos se encuentra en rangos considerados aceptables, según la clasificación actual, y el grupo control, mujeres menopáusicas sanas que no recibían ningún tipo de suplemento vitamínico, se encuentra con niveles desde 40ng/ml en un 100%.Discusión y conclusionesSegún nuestro estudio, los niveles de vitamina D3 han cambiado, pasando de una alta prevalencia de insuficiencia de vitamina D3 a rangos aceptables en un 26,8% de la población, con una mediana de 46,2ng/ml, considerando como rango de referencia 10–70ng/ml(AU)

IntroductionAccording to current classifications, the metabolite of greatest clinical interest to evaluate vitamin D3 dosage is 25-hydroxyvitamin D3 with a reference interval of approximately 10–70ng/ml, although many authors consider values of approximately 40ng/ml or 100nmol/l to be desirable. According to these definitions, three out of four people in Spain would have vitamin D3 deficiency.Material and methodThe RIA-CT technique was used for diagnosis of 25(OH)D3 to determine the population status. Subsequently, a case-control study was performed to evaluate the relationship between distinct diseases and vitamin D3 deficiency.ResultsA total of 73.2% of the cases were found to be within the range considered acceptable, according to the present classification. One hundred percent of the control group and healthy menopausal women who did not receive any kind of vitamin supplement had levels of 40ng/ml or more.Discussion and conclusionsOur results indicate that the prior situation of a high prevalence of vitamin D3 deficiency has improved and that levels are now acceptable in 26.8% of the population, with a mean value of 46.2ng/ml, considering 10–70ng/ml as the reference range(AU)

[Has vitamin D(3) dosage improved in Spain? Current levels in a population sample]. / ¿Ha mejorado la dotación de vitamina D(3) en España? Actuales niveles en una muestra de la población.

INTRODUCTION: According to current classifications, the metabolite of greatest clinical interest to evaluate vitamin D(3) dosage is 25-hydroxyvitamin D(3) with a reference interval of approximately 10-70ng/ml, although many authors consider values of approximately 40ng/ml or 100nmol/l to be desirable. According to these definitions, three out of four people in Spain would have vitamin D(3) deficiency. MATERIAL AND METHOD: The RIA-CT technique was used for diagnosis of 25(OH)D(3) to determine the population status. Subsequently, a case-control study was performed to evaluate the relationship between distinct diseases and vitamin D(3) deficiency. RESULTS: A total of 73.2% of the cases were found to be within the range considered acceptable, according to the present classification. One hundred percent of the control group and healthy menopausal women who did not receive any kind of vitamin supplement had levels of 40 ng/ml or more. DISCUSSION AND CONCLUSIONS: Our results indicate that the prior situation of a high prevalence of vitamin D(3) deficiency has improved and that levels are now acceptable in 26.8% of the population, with a mean value of 46.2 ng/ml, considering 10-70 ng/ml as the reference range.

Gouy wave modes: undistorted pulse focalization in a dispersive medium.

Gouy wave modes are linear waves with finite energy that propagate without distortion at any phase and group velocity through a focal region in a dispersive medium. These features make them potentially useful for the onset and control of nonlinear interactions.

Fisiología del envejecimiento y del estrés oxidativo (B40) / No disponible

No disponible

Effect of cosmological neutrinos on discrimination between the two enantiomers of a chiral molecule.

In the framework of an extraterrestrial origin of biological homochirality, universal mechanisms are of particular interest. In this sense we consider the weak parity-violating neutrino-electron interaction through weak charged currents W (+/-) between the relic flux of cosmological neutrinos and the electrons of a chiral molecule. We use the known theoretical result of the split in energy of the two helicity sates of an electron in the cosmic neutrino bath, due to weak charged currents. In the case that electrons of a chiral molecule are submitted to a helicoidal potential due to the nuclear conformation, these electrons have opposite helicities for the two enantiomers of the molecule and consequently the mentioned neutrino-electron interaction would produce a splitting in energy between the two enantiomers. An estimation of this energy for the case of a single electron yields a small value of the order of 10(-26) eV. This value results amplified by the contribution of all the molecular electrons having helicity and other possible mechanisms.

Cerebrospinal fluid markers in dementia with lewy bodies compared with Alzheimer disease.

BACKGROUND: Most patients with dementia with Lewy bodies (DLB) exhibit diffuse plaque-only pathology with rare neocortical neurofibrillary tangles (NFTs), as opposed to the widespread cortical neurofibrillary-tau involvement in Alzheimer disease (AD). Another pathological difference is the astrocytic and microglial inflammatory responses, including release of interleukins (ILs), around the neuritic plaques and NFTs in AD brains that are absent or much lower in DLB. We analyzed cerebrospinal fluid (CSF) markers that reflect the pathological differences between AD and DLB. OBJECTIVE: To determine CSF concentrations of tau, beta-amyloid, IL-1beta, and IL-6 as potential diagnostic clues to distinguish between AD and DLB. METHODS: We measured total tau, beta-amyloid1-42, IL-1beta, and IL-6 levels in CSF samples of 33 patients with probable AD without parkinsonism, 25 patients with all the core features of DLB, and 46 age-matched controls. RESULTS: Patients with AD had significantly higher levels of tau protein than patients with DLB and controls (P<.001). The most efficient cutoff value provided 76% specificity to distinguish AD and DLB cases. Patients with AD and DLB had lower, but not significantly so, beta-amyloid levels than controls. The combination of tau and beta-amyloid levels provided the best sensitivity (84%) and specificity (79%) to differentiate AD vs controls but was worse than tau values alone in discriminating between AD and DLB. Beta-amyloid levels had the best correlation with disease progression in both AD and DLB (P =.01). There were no significant differences in IL-1beta levels among patients with AD, patients with DLB, and controls. Patients with AD and DLB showed slightly, but not significantly, higher IL-6 levels than controls. CONCLUSIONS: The tau levels in CSF may contribute to the clinical distinction between AD and DLB. Beta-amyloid CSF levels are similar in both dementia disorders and reflect disease progression better than tau levels. Interleukin CSF concentrations do not distinguish between AD and DLB.

Pulsed light beams in vacuum with superluminal and negative group velocities.

We study the group velocity of pulsed light beams in vacuum. Gouy's phase associated with the diffraction of transversally limited pulses can create a strong anomalous dispersion in vacuum leading to highly superluminal and negative group velocities. As a consequence, a focusing pulse can diverge beyond the focus before converging into it. The experimental feasibility is discussed.

Steele-Richardson-Olszewski syndrome in a patient with a single C212Y mutation in the parkin protein.

Steele-Richardson-Olszewski syndrome (SROS) is a neurodegenerative disorder of unknown aetiology, most frequently sporadic. Familial cases of SROS have been described. An intronic polymorphism of the tau gene is associated with sporadic SROS and mutations of the tau gene are present in atypical cases of SROS. The role of tau has been excluded in other families with pathology proven SROS, suggesting that this syndrome may have multiple causes. An 82-year-old patient, father of 3 children with autosomal recessive juvenile parkinsonism due to combined heterozygous mutations of the parkin gene, developed clinical features of SROS 2 years before death. The diagnosis was confirmed by pathology. He carried the C212Y mutation of the parkin gene and was homozygous for the A0 polymorphism and for the H1 haplotype. The role of parkin in the processing of tau is discussed.

Progressive supranuclear palsy and tau hyperphosphorylation in a patient with a C212Y parkin mutation.

Autosomal recessive-juvenile parkinsonism (AR-JP) is one of the most common forms of familial Parkinson's disease (PD) and is related to mutations in the Park-2 gene, encoding for a protein ligase of ubiquitin, parkin. Different mutations located along the parkin gene have been observed in different AR-JP affected families, possibly interfering with the normal function of parkin and the proteasome system. Two cases of patients with AR-JP have been recently described presenting different homo- and heterozygous parkin mutations and limited tau pathology. We report here the case of a patient with clinical and pathological findings compatible with progressive supranuclear palsy (PSP), carrier of a single, heterozygous mutation of the parkin gene, and homozygous for the H1/H1 haplotype in the tau gene. Abnormal tau hyperphosphorylation has been observed in our patient brain samples, suggesting that a partial deficit of parkin, a protein with ubiquitin-ligase function, may trigger tau pathology in individuals with molecular genetic risk factors.

Patterns of protein nitration in dementia with Lewy bodies and striatonigral degeneration.

The synucleinopathies are a group of neurodegenerative disorders characterized by the presence of alpha-synuclein inclusions in neurons (Lewy body diseases, LBD) or glial cells (multiple system atrophies, MSA). Recently, nitration of alpha-synuclein has been reported as the possible modification that induces its aggregation and deposition in these disorders. In this study we investigated the distribution and relationships of alpha-synuclein inclusions and 3-nitrotyrosine (3-NT), a marker of protein nitration through oxidative mechanisms, in brains diagnosed with LBD or MSA and control brains using double immunohistochemical techniques. In LBD cases, 3-NT colocalized with alpha-synuclein immunoreactivity in classic and cortical Lewy bodies and in dystrophic neurites in substantia nigra. However, most pale bodies and diffuse deposits in substantia nigra and Lewy neurites in hippocampus lack 3-NT immunoreactivity. A majority of cases showed diffuse cytoplasmic 3-NT staining in pyramidal cells of the CA2-3 regions of the hippocampus that was independent of alpha-synuclein deposits. All MSA cases showed 3-NT immunoreactivity in glial inclusions. 3-NT neuronal staining was restricted to pontine nuclei with three cases showing nuclear and one case cytoplasmic staining. There was no colocalization of 3-NT nuclear immunoreactivity with alpha-synuclein-immunopositive nuclear inclusions in pontine neurons. These data show that protein nitration in LBD and MSA cases has a widespread distribution and is not only associated with the alpha-synuclein deposits. The presence of alpha-synuclein-positive deposits lacking 3-NT immunoreactivity suggests that nitration is not a prerequisite for alpha-synuclein deposition.

Effects of fibroblast growth factor and glial-derived neurotrophic factor on akinesia, F-DOPA uptake and dopamine cells in parkinsonian primates.

Parkinson's disease (PD) is a common neurodegenerative disorder that produces progressive disability despite symptomatic treatment. Several strategies, including stereotaxic brain lesions, deep brain stimulation, transplants of dopamine cells and administration of neurotrophic factors, have been proposed to improve efficacy and to counteract the progression of the disease. We here report the effects of repetitive intracerebral infusion of basic fibroblast growth factor (bFGF) and glial-derived neurotrophic factor, up to 1 year, in Cynomolgus monkeys with long standing asymmetric parkinsonism produced by unilateral intracarotid injection of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP). The treatment with neurotrophic factors was initiated when the parkinsonian deficits were stable, 6 months after the administration of MPTP. The evaluation of the response to the neurotrophic factors was performed by blind observers using: clinical scales that measured global motor deficit, motor ability in both hands, apomorphine-induced rotation, determination of the levels of monoamine metabolites in cerebrospinal fluid, and 6-F18-fluoro-l-DOPA (F-DOPA) uptake in the striatum and histology. Both factors, but bFGF more so, improve motor behavior, dopamine metabolism, striatal F-DOPA uptake, and the number of dopamine neurons. The procedure is well tolerated and provides a strong background for efficacy and safety of this treatment in patients with PD.