995 research outputs found
Understanding the effects of air pollution on neurogenesis and gliogenesis in the growing and adult brain
Exposure to air pollution - and particularly to particulate matter (PM) - is strongly associated with higher risk of neurodevelopmental disorders, poor mental health and cognitive defects. In animal models, disruption of CNS development and disturbances of adult neurogenesis contribute to PM neurotoxicity. Recent studies show that gestational PM exposure not only affects embryonic neurodevelopment, but also disturbs postnatal brain growth and maturation, by interfering with neurogenic/gliogenic events, myelination and synaptogenesis. Similarly, adult neurogenesis is affected at many levels, from neural stem cell amplification up to the maturation and integration of novel neurons in the adult brain parenchyma. The underlying mechanisms are still by and large unknown. Beyond microglia activation and neuroinflammation, recent studies propose a role for novel epigenetic mechanisms, including DNA methylation and extracellular vesicles-associated microRNAs
On the "spin-freezing" mechanism in underdoped superconducting cuprates
The letter deals with the spin-freezing process observed by means of NMR-NQR
relaxation or by muon spin rotation in underdoped cuprate superconductors. This
phenomenon, sometimes referred as coexistence of antiferromagnetic and
superconducting order parameters, is generally thought to result from randomly
distributed magnetic moments related to charge inhomogeneities (possibly
stripes) which exhibit slowing down of their fluctuations on cooling below
T . Instead, we describe the experimental findings as due to fluctuating,
vortex-antivortex, orbital currents state coexisting with d-wave
superconducting state. A direct explanation of the experimental results, in
underdoped YCaBaCuO and LaSrCuO,
is thus given in terms of freezing of orbital current fluctuations
Zero-Dimensional Superconducting Fluctuations and Fluctuating Diamagnetism in Lead Nanoparticles
High resolution SQUID magnetization measurements in lead nanoparticles are
used to study the fluctuating diamagnetism in zero-dimensional condition,
namely for particle size d lesser than the coherence length. The diamagnetic
magnetization Mdia (H, T= const) as a function of the field H at constant
temperature is reported in the critical region and compared with the behaviour
in the temperature range where the first-order fluctuation correction is
expected to hold. The magnetization curves are analysed in the framework of
exact fluctuation theories based on the Ginzburg-Landau functional for the
coherence length much greater than d. The role of the upturn field Hup where
Mdia reverses the field dependence is discussed and its relevance for the study
of the fluctuating diamagnetism, particularly in the critical region where the
first-order fluctuation correction breaks down, is pointed out. The size and
temperature dependence of Hup is theoretically derived and compared to the
experimental data. The relevance and the magnetization curves for
non-evanescent field and of the upturn field for the study of the fluctuating
diamagnetism above the superconducting transition temperature is emphasized
Nuclear classical dynamics of H in intense laser field
In the first part of this paper, the different distinguishable pathways and
regions of the single and sequential double ionization are determined and
discussed. It is shown that there are two distinguishable pathways for the
single ionization and four distinct pathways for the sequential double
ionization. It is also shown that there are two and three different regions of
space which are related to the single and double ionization respectively. In
the second part of the paper, the time dependent Schr\"{o}dinger and Newton
equations are solved simultaneously for the electrons and the nuclei of H
respectively. The electrons and nuclei dynamics are separated on the base of
the adiabatic approximation. The soft-core potential is used to model the
electrostatic interaction between the electrons and the nuclei. A variety of
wavelengths (390 nm, 532 nm and 780 nm) and intensities (
and ) of the ultrashort intense laser
pulses with a sinus second order envelope function are used. The behaviour of
the time dependent classical nuclear dynamics in the absence and present of the
laser field are investigated and compared. In the absence of the laser field,
there are three distinct sections for the nuclear dynamics on the electronic
ground state energy curve. The bond hardening phenomenon does not appear in
this classical nuclear dynamics simulation.Comment: 16 pages, 7 figure
HSD17B13 and other liver fat-modulating genes predict development of hepatocellular carcinoma among HCV-positive cirrhotics with and without viral clearance after DAA treatment
Background: Genetic predisposition to accumulate liver fat (expressed by a polygenic risk score, GRS, based on the number of at-risk alleles of PNPLA3, TM6SF2, MBOAT7 and GCKR) may influence the probability of developing hepatocellular carcinoma (HCC) after hepatitis C treatment. Whether this holds true taking into account carriage of the HSD17B13:TA splice variant, also affecting lipogenesis, and achievement of viral clearance (SVR), is unknown. Methods: PNPLA3, TM6SF2, MBOAT7, GCKR and HSD17B13 variants were determined in a cohort of 328 cirrhotic patients free of HCC before starting treatment with direct acting antivirals (DAA). Results: SVR in the study cohort was 96%. At the end of follow-up, N = 21 patients had been diagnosed an HCC; none of the genes included in the GRS was individually associated with HCC development. However, in a Cox proportional hazards model, a GRS > 0.457 predicted HCC independently of sex, diabetes, albumin, INR and FIB4. The fit of the model improved adding treatment outcome and carriage of the HSD17B13:TA splice variant, with sex, GRS > 0.457, HSD17B13:TA splice variant and failure to achieve an SVR (hazard ratio = 6.75, 4.24, 0.24 and 7.7, respectively) being independent predictors of HCC. Conclusion: Our findings confirm that genes modulating liver fat and lipogenesis are important risk factors for HCC development among cirrhotics C treated with DAA
Towards large scale automated cage monitoring - Diurnal rhythm and impact of interventions on in-cage activity of C57BL/6J mice recorded 24/7 with a non-disrupting capacitive-based technique.
BACKGROUND AND AIMS: Automated recording of laboratory animal\u27s home cage behavior is receiving increasing attention since such non-intruding surveillance will aid in the unbiased understanding of animal cage behavior potentially improving animal experimental reproducibility.
MATERIAL AND METHODS: Here we investigate activity of group held female C57BL/6J mice (mus musculus) housed in standard Individually Ventilated Cages across three test-sites: Consiglio Nazionale delle Ricerche (CNR, Rome, Italy), The Jackson Laboratory (JAX, Bar Harbor, USA) and Karolinska Insititutet (KI, Stockholm, Sweden). Additionally, comparison of female and male C57BL/6J mice was done at KI. Activity was recorded using a capacitive-based sensor placed non-intrusively on the cage rack under the home cage collecting activity data every 250 msec, 24/7. The data collection was analyzed using non-parametric analysis of variance for longitudinal data comparing sites, weekdays and sex.
RESULTS: The system detected an increase in activity preceding and peaking around lights-on followed by a decrease to a rest pattern. At lights off, activity increased substantially displaying a distinct temporal variation across this period. We also documented impact on mouse activity that standard animal handling procedures have, e.g. cage-changes, and show that such procedures are stressors impacting in-cage activity. These key observations replicated across the three test-sites, however, it is also clear that, apparently minor local environmental differences generate significant behavioral variances between the sites and within sites across weeks. Comparison of gender revealed differences in activity in the response to cage-change lasting for days in male but not female mice; and apparently also impacting the response to other events such as lights-on in males. Females but not males showed a larger tendency for week-to-week variance in activity possibly reflecting estrous cycling.
CONCLUSIONS: These data demonstrate that home cage monitoring is scalable and run in real time, providing complementary information for animal welfare measures, experimental design and phenotype characterization
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