439 research outputs found
Holographic perfect fluidity, Cotton energy-momentum duality and transport properties
We investigate background metrics for 2+1-dimensional holographic theories
where the equilibrium solution behaves as a perfect fluid, and admits thus a
thermodynamic description. We introduce stationary perfect-Cotton geometries,
where the Cotton--York tensor takes the form of the energy--momentum tensor of
a perfect fluid, i.e. they are of Petrov type D_t. Fluids in equilibrium in
such boundary geometries have non-trivial vorticity. The corresponding bulk can
be exactly reconstructed to obtain 3+1-dimensional stationary black-hole
solutions with no naked singularities for appropriate values of the black-hole
mass. It follows that an infinite number of transport coefficients vanish for
holographic fluids. Our results imply an intimate relationship between
black-hole uniqueness and holographic perfect equilibrium. They also point
towards a Cotton/energy--momentum tensor duality constraining the fluid
vorticity, as an intriguing boundary manifestation of the bulk mass/nut
duality.Comment: V3: 1+39 pages, JHEP versio
Opportunities and challenges for the nasal administration of nanoemulsions
© 2015 Bentham Science Publishers. Nasal delivery has become a growing area of interest for drug administration as a consequence of several practical advantages, such as ease of administration and non-invasiveness. Moreover, the avoidance of hepatic first-pass metabolism and rapid and efficient absorption across the permeable nasal mucosa offer a promising alternative to other traditional administration routes, such as oral or parenteral delivery. In fact, nasal delivery has been proposed for a number of applications, including local, systemic, direct nose-to-brain and mucosal vaccine delivery. Nanoemulsions, due to their stability, small droplet size and optimal solubilization properties, represent a versatile formulation approach suitable for several administration routes. Nanoemulsions demonstrated great potential in nasal drug delivery, increasing the absorption and the bioavailability of many drugs for systemic and nose-tobrain delivery. Furthermore, they act as an active component, i.e. an adjuvant, in nasal mucosal vaccinations, displaying the ability to induce robust mucosal immunity, high serum antibodies titres and a cellular immune response avoiding inflammatory response. Interestingly, nanoemulsions have not been proposed for the treatment of local ailments of the nose. Despite the promising results in vitro and in vitro, the application of nanoemulsions for nasal delivery in humans appears mainly hindered by the lack of detailed toxicology studies to determine the effect of these formulations on the nasal mucosa and cilia and the lack of extensive clinical trials
Impact of Cooking on Bioactive Compounds and Antioxidant Activity of Pigmented Rice Cultivars
Pigmented rice cultivars, namely Venere and Artemide, are a source of bioactive molecules, in particular phenolics, including anthocyanins, exerting a positive effect on cardiovascular systems thanks also to their antioxidant capacity. This study aimed to determine the total phenol index (TPI), total flavonoids (TF), total anthocyanins (TA) and in vitro antioxidant capacity in 12 batches of Venere cultivar and two batches of Artemide cultivar. The rice was cooked using different methods (boiling, microwave, pressure cooker, water bath, rice cooker) with the purpose to individuate the procedure limiting the loss of bioactive compounds. TPI, TF and TA were spectrophotometrically determined in both raw and cooked rice samples. Rice samples of Artemide cultivars were richer in TPI (17.7-18.8 vs. 8.2-11.9 g gallic acid/kg in Venere rice), TF (13.1 vs. 5.0-7.1 g catechin/kg rice for Venere rice) and TA (3.2-3.4 vs. 1.8-2.9 g Cy-3glc/kg for Venere rice) in comparison to those of Venere cultivar; as well, they showed higher antioxidant capacity (46.6-47.8 vs. 14.4-31.9 mM Trolox/kg for Venere rice). Among the investigated cooking methods, the rice cooker and the water bath led to lower and comparable losses of phenolics. Interestingly, the cooking water remaining after cooking with the rice cooker was rich in phenolics. The consumption of a portion of rice (100 g) cooked with the rice cooker with its own cooking water can supply 240 mg catechin and 711 mg cyanidin 3-O-glucoside for Venere rice and 545 mg catechin and 614 mg cyanidin 3-O-glucoside for Artemide rice, with a potential positive effect on health
Anti-Inflammatory Properties of Statin-Loaded Biodegradable Lecithin/Chitosan Nanoparticles: A Step Toward Nose-to-Brain Treatment of Neurodegenerative Diseases
Nasal delivery has been indicated as one of the most interesting alternative routes for the brain delivery of neuroprotective drugs. Nanocarriers have emerged as a promising strategy for the delivery of neurotherapeutics across the nasal epithelia. In this work, hybrid lecithin/chitosan nanoparticles (LCNs) were proposed as a drug delivery platform for the nasal administration of simvastatin (SVT) for the treatment of neuroinflammatory diseases. The impact of SVT nanoencapsulation on its transport across the nasal epithelium was investigated, as well as the efficacy of SVT-LCNs in suppressing cytokines release in a cellular model of neuroinflammation. Drug release studies were performed in simulated nasal fluids to investigate SVT release from the nanoparticles under conditions mimicking the physiological environment present in the nasal cavity. It was observed that interaction of nanoparticles with a simulated nasal mucus decreased nanoparticle drug release and/or slowed drug diffusion. On the other hand, it was demonstrated that two antibacterial enzymes commonly present in the nasal secretions, lysozyme and phospholipase A2, promoted drug release from the nanocarrier. Indeed, an enzyme-triggered drug release was observed even in the presence of mucus, with a 5-fold increase in drug release from LCNs. Moreover, chitosan-coated nanoparticles enhanced SVT permeation across a human cell model of the nasal epithelium (×11). The nanoformulation pharmacological activity was assessed using an accepted model of microglia, obtained by activating the human macrophage cell line THP-1 with the Escherichia coli-derived lipopolysaccharide (LPS) as the pro-inflammatory stimulus. SVT-LCNs were demonstrated to suppress the pro-inflammatory signaling more efficiently than the simple drug solution (-75% for IL-6 and -27% for TNF-α vs. -47% and -15% at 10 µM concentration for SVT-LCNs and SVT solution, respectively). Moreover, neither cellular toxicity nor pro-inflammatory responses were evidenced for the treatment with the blank nanoparticles even after 36 h of incubation, indicating a good biocompatibility of the nanomedicine components in vitro. Due to their biocompatibility and ability to promote drug release and absorption at the biointerface, hybrid LCNs appear to be an ideal carrier for achieving nose-to-brain delivery of poorly water-soluble drugs such as SVT
A mechanistic investigation of the ruthenium porphyrin catalysed aziridination of olefins by aryl azides
A combination of DFT and kinetic studies suggests a mechanism for olefin aziridination by organic azides catalysed by ruthenium porphyrins
Correlazione tra anosognosia e rischio di cadute nel paziente cerebroleso postacuto
Introduzione
L\u2019anosognosia per l\u2019emiplegia \ue8 un disturbo neuropsicologico derivante da una lesione cerebrale che comporta l\u2019inconsapevolezza del deficit motorio. Il paziente inconsapevole del proprio deficit motorio \ue8 esposto a comportamenti talora pericolosi che potrebbero aumentare il rischio di caduta.
Lo studio si propone d\u2019identificare la presenza di anosognosia nei pazienti con lesione cerebrale in fase post-acuta, di valutare la possibile correlazione tra il grado di anosognosia e il deficit motorio acquisito e tra il grado di anosognosia e il rischio di caduta.
Materiali e metodi
E\u2019 stato condotto uno studio osservazionale su 16 pazienti con lesione cerebrale conseguente a ictus ischemico o emorragico in fase post-acuta. Ciascun paziente \ue8 stato sottoposto al Visual Analogue Test for Anosognosia for motor Impairment (VATAm) e valutato con la scala per l\u2019anosognosia per l\u2019emiplegia di Bisiach per l\u2019eventuale deficit di consapevolezza corporea, con la National Institute of Health Stroke Scale (NIHSS) per quantificare il deficit neurologico, con la Motricity Index Scale (MIS) per valutare le capacit\ue0 motorie e con la Morse Fall Scale per il rischio di caduta.
Per l'analisi statistica delle variabili oggetto dello studio \ue8 stato utilizzato un test non parametrico (Indice di correlazione di Spearman).
Risultati
Cinque dei 16 pazienti esaminati sono risultati anosognosici (31 %). Tre pazienti (60%) avevano una lesione emisferica destra, mentre due (40%) una lesione emisferica sinistra. Tutti i pazienti anosognosici avevano un deficit di sensibilit\ue0 e nel 40% dei casi anche eminattenzione.
Dall\u2019analisi statistica \ue8 emerso che nel campione esaminato l\u2019anosognosia \ue8 correlata alla gravit\ue0 del deficit motorio dell'arto superiore (MIS AS, p = 0,0014), ma non alla gravit\ue0 del deficit motorio dell'arto inferiore (MIS AI, p = 0,25). Inoltre l'anosognosia \ue8 risultata fortemente correlata al rischio di caduta (p < 0,0001), mentre il rischio di caduta \ue8 correlato al deficit motorio dell'arto superiore (MIS AS, p = 0,04), ma non dell'arto inferiore (MIS AI, p = 0,1).
Conclusioni
Da questi risultati emerge che la presenza di anosognosia aumenta il rischio di caduta indipendente-mente dalla gravit\ue0 del deficit motorio e ci\uf2 pu\uf2 influenzare negativamente l'outcome funzionale e allungare i tempi di degenza. In particolare, la correlazione tra il grado di anosognosia e la gravit\ue0 del deficit motorio dell\u2019arto superiore, ma non dell\u2019arto inferiore, suggerisce che i pazienti a maggior rischio di caduta sono quelli non consapevoli del deficit motorio, in grado per\uf2 di mobilizzarsi e, per il deficit dell'arto superiore, con ridotte reazioni anticipatorie e posturali di difesa
From early stress to 12-month development in very preterm infants: Preliminary findings on epigenetic mechanisms and brain growth
Very preterm (VPT) infants admitted to Neonatal Intensive Care Unit (NICU) are at risk for altered brain growth and less-than-optimal socio-emotional development. Recent research suggests that early NICU-related stress contributes to socio-emotional impairments in VPT infants at 3 months through epigenetic regulation (i.e., DNA methylation) of the serotonin transporter gene (SLC6A4). In the present longitudinal study we assessed: (a) the effects of NICU-related stress and SLC6A4 methylation variations from birth to discharge on brain development at term equivalent age (TEA); (b) the association between brain volume at TEA and socio-emotional development (i.e., Personal-Social scale of Griffith Mental Development Scales, GMDS) at 12 months corrected age (CA). Twenty-four infants had complete data at 12-month-age. SLC6A4 methylation was measured at a specific CpG previously associated with NICU-related stress and socio-emotional stress. Findings confirmed that higher NICU-related stress associated with greater increase of SLC6A4 methylation at NICU discharge. Moreover, higher SLC6A4 discharge methylation was associated with reduced anterior temporal lobe (ATL) volume at TEA, which in turn was significantly associated with less-than-optimal GMDS Personal-Social scale score at 12 months CA. The reduced ATL volume at TEA mediated the pathway linking stress-related increase in SLC6A4 methylation at NICU discharge and socio-emotional development at 12 months CA. These findings suggest that early adversity-related epigenetic changes might contribute to the long-lasting programming of socio-emotional development in VPT infants through epigenetic regulation and structural modifications of the developing brain
Impact of Thoracoscopic Pulmonary Vein Isolation on Right Ventricular Function:A Pilot Study
Objective. Thoracoscopic surgical pulmonary vein isolation (sPVI) has been added to the treatment of atrial fibrillation (AF), showing excellent efficacy outcomes. However, data on right ventricular (RV) function following sPVI has never been studied. Our aim was to investigate RV function following sPVI and compare it to patients who underwent endocardial cryoballoon PVI. Methods. 25 patients underwent sPVI and were pair-matched according to age, sex, and AF type with 21 patients who underwent cryoballoon PVI. RV function was measured using tricuspid annular plane systolic excursion (TAPSE) and RV strain with 2D speckle tracking. Echocardiography was performed at baseline and at median 6-month follow-up. Results. Age was 54 ± 9 years and 84% were male; AF was paroxysmal in 92%. In the sPVI group, TAPSE was reduced with 31% at follow-up echocardiography (p<0.001) and RV strain showed a 25% reduction compared to baseline (p=0.018). In the control group, TAPSE and RV strain did not change significantly (−3% and +13%, p=0.410 and p=0.148). Change in TAPSE and RV strain was significantly different between groups (p≤0.001 and p=0.005). Conclusions. This study shows that RV function is significantly decreased following sPVI. This effect was not observed in the cryoballoon PVI control group
Ancient Evolution of Mammarenaviruses: Adaptation via Changes in the L Protein and No Evidence for Host-Virus Codivergence
The Mammarenavirus genus includes several pathogenic species of rodent-borne viruses. Old World (OW) mammarenaviruses infect rodents in the Murinae subfamily and are mainly transmitted in Africa and Asia; New World (NW) mammarenaviruses are found in rodents of the Cricetidae subfamily in the Americas. We applied a selection-informed method to estimate that OW and NW mammarenaviruses diverged less than 3c45,000\u2009years ago (ya). By incorporating phylogeographic inference, we show that NW mammarenaviruses emerged in the Latin America-Caribbean region 3c41,400-3,300 ya, whereas OW mammarenaviruses originated 3c23,100-1,880 ya, most likely in Southern Africa. Cophylogenetic analysis indicated that cospeciation did not contribute significantly to mammarenavirus-host associations. Finally, we show that extremely strong selective pressure on the viral polymerase accompanied the speciation of NW viruses. These data suggest that the evolutionary history of mammarenaviruses was not driven by codivergence with their hosts. The viral polymerase should be regarded as a major determinant of mammarenavirus adaptation
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