2,849 research outputs found
Nutrition and dementia: Evidence for preventive approaches?
In recent years, the possibility of favorably influencing the cognitive trajectory through
promotion of lifestyle modifications has been increasingly investigated. In particular, the relationship
between nutritional habits and cognitive health has attracted special attention. The present review
is designed to retrieve and discuss recent evidence (published over the last 3 years) coming from
randomized controlled trials (RCTs) investigating the efficacy of nutritional interventions aimed
at improving cognitive functioning and/or preventing cognitive decline in non-demented older
individuals. A systematic review of literature was conducted, leading to the identification of 11 studies
of interest. Overall, most of the nutritional interventions tested by the selected RCTs were found
to produce statistically significant cognitive benefits (defined as improved neuropsychological test
scores). Nevertheless, the clinical meaningfulness of such findings was not adequately discussed and
appears controversial. In parallel, only 2 studies investigated between-group differences concerning
incident dementia and mild cognitive impairment cases, reporting conflicting results. Results of
the present review suggest that several dietary patterns and nutritional components may constitute
promising strategies in postponing, slowing, and preventing cognitive decline. However, supporting
evidence is overall weak and further studies are needed
The unique case of the AGN core of M87: a misaligned low power blazar?
M87 hosts one of the closest jetted active galactic nucleus (AGN) to Earth.
Thanks to its vicinity and to the large mass of is central black hole, M87 is
the only source in which the jet can be directly imaged down to near-event
horizon scales with radio very large baseline interferometry (VLBI). This
property makes M87 a unique source to isolate and study jet launching,
acceleration and collimation. In this paper we employ a multi-zone model
designed as a parametrisation of general relativistic magneto-hydrodynamics
(GRMHD); for the first time we reproduce the jet's observed shape and
multi-wavelength spectral energy distribution (SED) simultaneously. We find
strong constraints on key physical parameters of the jet, such as the location
of particle acceleration and the kinetic power. However, we under-predict the
(unresolved) {\gamma}-ray flux of the source, implying that the high-energy
emission does not originate in the magnetically-dominated inner jet regions.
Our results have important implications both for comparisons of GRMHD
simulations with observations, and for unified models of AGN classes.Comment: 12 pages, 7 figures, accepted for publication on MNRAS, comments are
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The dynamics of the β-propeller domain in Kelch protein KLHL40 changes upon nemaline myopathy-associated mutation
Evolutionarily widespread, functionally and structurally diverse and still largely unexplored, Kelch proteins, characterized by the presence of a conserved C-terminal β-propeller, are implicated in a number of diverse fundamental biological functions, including cytoskeletal arrangement, regulation of cell morphology and organization, and protein degradation. Mutations in the genes encoding for Kelch superfamily members are being discovered as the cause of several neuromuscular diseases and cancer. The E528K mutation in Kelch protein KLHL40, which regulates skeletal muscle myogenesis, has been identified as a frequent cause of severe autosomal-recessive nemaline myopathy (NM). We use all-atom molecular dynamics simulations to characterize the dynamic behaviour of the β-propeller of the wild-type protein and identify correlated motions underlying the in vivo functionality. We also modelled the NM-associated mutation and we found that it does not lead to dramatic disruption of the β-propeller architecture; yet, residue 528 is a hub in the correlated motions of the domain, and mutation-induced local structural alterations are propagated to the whole protein, affecting its dynamics and physicochemical properties, which are fundamental for in vivo interaction with partners. Our results indicate that rational design of drugs can be envisioned as a strategy for restoring the internal network of communication and resetting KLHL40 to its physiological state
Venturi mask is the pioneer of High-Flow Oxygen Therapy Concepts
Oxygen therapy should be carefully considered and monitored because, as any other medications, it can cause harm to patients, if used inappropriately. This paper focus on the distinction between low-flow and high-flow oxygen therapy. A discussion about Venturi system for oxygen administration is carried on, given that some authors include it in the low-flow devices group despite its characteristics to deliver high flow therapy
Role of intra-band transitions in photo-carrier generation
We theoretically investigate the role of intra-band transitions in
laser-induced carrier-generation for different photon energy regimes: (i)
strongly off-resonant, (ii) multi-photon resonant, and (iii) resonant
conditions. Based on the analysis for the strongly off-resonant and
multi-photon resonant cases, we find that intra-band transitions strongly
enhance photo-carrier generation in both multi-photon absorption and tunneling
excitation regimes, and thus, they are indispensable for describing the
nonlinear photo-carrier generation processes. Furthermore, we find that
intra-band transitions enhance photo-carrier generation even in the resonant
condition, opening additional multi-photon excitation channels once the laser
irradiation becomes sufficiently strong. The above findings suggest a potential
for efficient control of photo-carrier generation via multi-color laser pulses
through optimization of the contributions from intra-band transitions
The peculiar variable X-ray spectrum of the active galactic nucleus PKS 2005-489
PKS 2005-489 is a well-known, bright southern BL Lac object that has been
detected up to TeV energies. In a low-flux state it exhibits the expected
multiwavelength double-peaked spectrum in the radio -- -ray band. The
high-flux state shows extreme flux variations in the X-ray band with a
hardening as well as a peculiar curved feature in the spectrum. Thus far, PKS
2005-489 is the only source to exhibit such a feature. To study the X-ray
variability further, we obtained the first hard X-ray spectrum of the source
with NuSTAR. We compare quasi-simultaneous radio, optical, UV, soft and hard
X-ray, and -ray data of PKS 2005-489 to archival data in order to study
its broadband behavior. We find a very consistent quiet state in the SED, with
little variation in spectral shape or flux between the 2012 and 2020 data. A
possible explanation for the peculiar X-ray spectrum in the flaring state is an
additional component in the jet, possibly accelerated via magnetic
reconnection, that is not co-spatial to the low-flux state emission region
The RSC chromatin-remodeling complex influences mitotic exit and adaptation to the spindle assembly checkpoint by controlling the Cdc14 phosphatase
Rsc2 promotes Cdc14 release from the nucleolus to free cells from mitotic arrest
Time-frequency mapping of two-colour photoemission driven by harmonic radiation
The use of few-femtosecond, extreme ultraviolet (XUV) pulses, produced by
high-order harmonic generation, in combination with few-femtosecond infrared
(IR) pulses in pump-probe experiments has great potential to disclose ultrafast
dynamics in molecules, nanostructures and solids. A crucial prerequisite is a
reliable characterization of the temporal properties of the XUV and IR pulses.
Several techniques have been developed. The majority of them applies phase
reconstruction algorithms to a photoelectron spectrogram obtained by ionizing
an atomic target in a pump-probe fashion. If the ionizing radiation is a single
harmonic, all the information is encoded in a two-color two-photon signal
called sideband (SB). In this work, we present a simplified model to interpret
the time-frequency mapping of the SB signal and we show that the temporal
dispersion of the pulses directly maps onto the shape of its spectrogram.
Finally, we derive an analytical solution, which allows us to propose a novel
procedure to estimate the second-order dispersion of the XUV and IR pulses in
real time and with no need for iterative algorithms
CADASIL or MS? Consider “Red Flags” but Avoid a Misdiagnosis: Case Series of a Concomitant Diagnosis
Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is a monogenic autosome-dominant disease with chronic clinical course. Rarely, CADASIL may present with atypical relapsing-remitting manifestations, cerebral and spinal white matter lesions, mimicking inflammatory CNS disease as multiple sclerosis (MS). The rarely co-occurrence of MS and CADASIL may represent a hard challenging diagnosis even for an expert neurologist. Here, we present a case series of two patients with CADASIL showing MRI pattern overlapping MS. They were the only case of co-occurrence of CADASIL and MS in their own family. Both patients were treated with anti-inflammatory and anti-platelet drugs, mostly with good response. Pathogenic hypothesis highlights that genetic events, related to monogenic disease, may expose CNS antigens with a consequent self-immune attack. In CADASIL, the function of Notch3 receptor showed a consistent interplay with immune system activity. Indeed, certain mutations of Notch3 receptor show abnormal upregulation of specific pro-inflammatory patterns. However, even if it is not possible to determinate if the proinflammatory activity may be promoted by pathogenic mutations in Notch3, the "apparent" difference between MS and “inflammatory CADASIL” could be considered more semantic than etiologic
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