646 research outputs found
Renormalization of Coulomb interactions in s-wave superconductor NaCoO
We study the renormalized Coulomb interactions due to retardation effect in
NaCoO. Although the Morel-Anderson's pseudo potential for
orbital is relatively large because the direct Coulomb repulsion
is large, that for interband transition between and
orbitals is very small since the renormalization factor for
pair hopping is square of that for . Therefore, the s-wave
superconductivity due to valence-band Suhl-Kondo mechanism will survive against
strong Coulomb interactions. The interband hopping of Cooper pairs due to shear
phonons is essential to understand the superconductivity in NaCoO.Comment: 2pages, 2figures, Proceedings of ICM in Kyoto, 200
The FDA “black box” warning on antidepressant suicide risk in young adults: More harm than benefits?
The decision made in the year 2004 by the U.S. Food and Drug Administration (FDA) to require a boxed warning on antidepressants regarding the risk of suicidality in young adults still represents a matter of controversy. The FDA warning was grounded on industry-sponsored trials carried one decade ago or earlier. However, within the past decade, an increasing number of reports have questioned the actual validity of the FDA warning, especially considering a decline in the prescription of the antidepressant drugs associated with an increase in the rate of suicidal events among people with severe depression. The present report provides an overview of the FDA black box warning, also documenting two Major Depressive Disorder patients whose refusal to undergo a pharmacological antidepressant treatment possibly led to an increased risk for suicidal behaviors. The concerns raised by the FDA black box warning need to be considered in real-world clinical practice, stating the associated clinical and public health implications
Synchrotron Emission from Hot Accretion Flows and the Cosmic Microwave Background Anisotropy
Current estimates of number counts of radio sources in the frequency range
where the most sensitive Cosmic Microwave Background (CMB) experiments are
carried out significantly under-represent sources with strongly inverted
spectra. Hot accretion flows around supermassive black holes in the nuclei of
nearby galaxies are expected to produce inverted radio spectra by thermal
synchrotron emission. We calculate the temperature fluctuations and power
spectra of these sources in the Planck Surveyor 30 GHz energy channel, where
their emission is expected to peak. We find that their potential contribution
is generally comparable to the instrumental noise, and approaches the CMB
anisotropy level at small angular scales. Forthcoming CMB missions, which will
provide a large statistical sample of inverted-spectra sources, will be crucial
for determining the distribution of hot accretion flows in nearby quiescent
galactic nuclei. Detection of these sources in different frequency channels
will help constrain their spectral characteristics, hence their physical
properties.Comment: 10 pages, 4 figures, accepted for publication in Ap
Radio Foregrounds for the 21cm Tomography of the Neutral Intergalactic Medium at High Redshifts
Absorption or emission against the cosmic microwave background radiation
(CMB) may be observed in the redshifted 21cm line if the spin temperature of
the neutral intergalactic medium prior to reionization differs from the CMB
temperature. This so-called 21cm tomography should reveal important information
on the physical state of the intergalactic medium at high redshifts. The
fluctuations in the redshifted 21 cm, due to gas density inhomogeneities at
early times, should be observed at meter wavelengths by the next generation
radio telescopes such as the proposed {\it Square Kilometer Array (SKA)}. Here
we show that the extra-galactic radio sources provide a serious contamination
to the brightness temperature fluctuations expected in the redshifted 21 cm
emission from the IGM at high redshifts. Unless the radio source population
cuts off at flux levels above the planned sensitivity of SKA, its clustering
noise component will dominate the angular fluctuations in the 21 cm signal. The
integrated foreground signal is smooth in frequency space and it should
nonetheless be possible to identify the sharp spectral feature arising from the
non-uniformities in the neutral hydrogen density during the epoch when the
first UV sources reionize the intergalactic medium.Comment: 5 pages emulateapj with 1 figure, accepted to Ap
The efficacy of trabecular titanium cages to Induce reparative bone activity after lumbar arthrodesis studied through the 18f-Naf PET/CT scan: observational clinical in-vivo study
Background: Titanium trabecular cages (TTCs) are emerging implants designed to achieve immediate and long-term spinal fixation with early osseointegration. However, a clear radiological and clinical demonstration of their efficacy has not yet been obtained. The purpose of this study was to evaluate the reactive bone activity of adjacent plates after insertion of custom-made titanium trabecular cages for the lumbar interbody with positron emission tomography (PET)/computed tomography (CT) 18F sodium fluoride (18F-NaF). Methods: This was an observational clinical study that included patients who underwent surgery for degenerative disease with lumbar interbody fusion performed with custom-made TTCs. Data related to the metabolic-reparative reaction following the surgery and its relationship with clinical follow-up from PET/CT performed at different weeks were evaluated. PET/CTs provided reliable data, such as areas showing abnormally high increases in uptake using a volumetric region of interest (VOI) comprising the upper (UP) and lower (DOWN) limits of the cage. Results: A total of 15 patients was selected for PET examination. Timing of PET/CTs ranged from one week to a maximum of 100 weeks after surgery. The analysis showed a negative correlation between the variables SUVmaxDOWN/time (r = −0.48, p = 0.04), ratio-DOWN/time (r = −0.53, p = 0.02), and ratio-MEAN/time (r = −0.5, p = 0.03). Shapiro−Wilk normality tests showed significant results for the variables ratio-DOWN (p = 0.002), ratio-UP (0.013), and ratio-MEAN (0.002). Conclusions: 18F-NaF PET/CT has proven to be a reliable tool for investigating the metabolic-reparative reaction following implantation of TTCs, demonstrating radiologically how this type of cage can induce reparative osteoblastic activity at the level of the vertebral endplate surface. This study further confirms how electron-beam melting (EBM)-molded titanium trabecular cages represent a promising material for reducing hardware complication rates and promoting fusion
Effect of continuous flow HTST treatments on donkey milk nutritional quality
Nutritional quality of raw donkey milk (DM) may be impaired during sanitization with the current batch holder pasteurization systems (62.5 degrees C for 30 min). In this paper, we present the preliminary results concerning the effects of high temperature for short time (HTST) protocols using an innovative in continuous low flow rate pasteurization plant (60 dm3/h) on B-vitamins group, antioxidant capacity, lysozyme and beta-lactoglobulin in DM. Lysozyme, beta-lactoglobulin and antioxidant power decreased after the thermal treatments, with characteristics depending on the extent of the heat treatment. The lysozyme content was substantially reduced between 20 and 60%, while the degradation of beta-lactoglobulin was lower (2-22%). No vitamin B1 and B12 were found in raw milk, whereas were detected vitamin B2 (0.17 mu mol/L), nicotinic acid (13.28 mu mol/L), B6 (2.06 mu mol/L) and B9 (0.75 mu mol/L). The heat treatments carried out with the innovative plant ensured vitamin retention, as no significant differences were found against the raw milk (p > 0.05). The preliminary results from this study represent a guidance to the establishment of DM pasteurization standards parameters with the perspective to improve DM nutritional quality
Plasma proteins containing damaged L-isoaspartyl residues are increased in uremia: Implications for mechanism
Plasma proteins containing damaged L-isoaspartyl residues are increased in uremia: Implications for mechanism.BackgroundSeveral alterations of protein structure and function have been reported in uremia. Impairment of a transmethylation-dependent protein repair mechanism possibly related to a derangement in homocysteine metabolism is also present in this condition, causing erythrocyte membrane protein damage. Homocysteine may affect proteins via the accumulation of its parent compound S-adenosylhomocysteine (AdoHcy), a powerful in vivo methyltransferase inhibitor. However, since plasma homocysteine is mostly protein bound, a direct influence on protein structures cannot be ruled out. We measured the levels of L-isoaspartyl residues in plasma proteins of uremic patients on hemodialysis. These damaged residues are markers of molecular age, which accumulate when transmethylation-dependent protein repair is inhibited and/or protein instability is increased.MethodsL-isoaspartyl residues in plasma proteins were quantitated using human recombinant protein carboxyl methyl transferase (PCMT). Plasma concentrations of homocysteine metabolites were also measured under different experimental conditions in hemodialysis patients.ResultsThe concentration of damaged plasma proteins was increased almost twofold compared to control (controls 147.83 ± 17.75, uremics 282.80 ± 26.40 pmol of incorporated methyl groups/mg protein, P < 0.003). The major protein involved comigrated with serum albumin. Although hyperhomocysteinemia caused a redistribution of thiols bound to plasma proteins, this mechanism did not significantly contribute to the increase in isoaspartyl residues. The S-adenosylmethionine (AdoMet)/AdoHcy concentration ratio, an indicator of the flux of methyl group transfer, was altered. This ratio was partially corrected by folate treatment (0.385 ± 0.046 vs. 0.682 ± 0.115, P < 0.01), but protein L-isoaspartate content was not.ConclusionsPlasma protein damage, as determined by protein L-isoaspartyl content, is increased in uremia. This alteration is to be ascribed to an increased protein structural instability, rather than the effect of hyperhomocysteinemia
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