425 research outputs found
Substitution of a commercial diet with raw meat complemented with vegetable foods containing chickpeas or peas affects faecal microbiome in healthy dogs
The aim of the study was to investigate if the inclusion of chickpeas or peas in the diet can modify faecal microbiome in dogs. Eight healthy adult Border collie, fed a commercial extruded diet as reference diet (RD), were divided in two groups of four individuals. At the beginning of the trial, one group received a diet based mainly of raw meat, rice and chickpeas (CP) and in the other group this pulse was substituted with peas (PE). After 14 days, the dogs with CP diet shifted to the PE and those with PE shifted to the CP diet, for another 14 days. Faeces were col- lected at the beginning (T0), after 14 days (T14) and at the end of the study (T28). Faeces were analysed for 16S rRNA, short chain fatty acids (SCFA), lactate, pH and faecal score was also eval- uated. The SCFA and lactate in the faeces were not affected by the inclusion of pulses, with the only exception of isovalerate, which was higher in CP and PE diets in comparison with RD diet (p < .05). The abundances of Erysipelotrichaceae incertae sedis, Eubacterium, Anaerobacter and Sarcina significantly differed in CP and PE in comparison with RD. Moreover, the genera Prevotella, Lactobacillus, Alloprevotella, Suttarella varied significantly between CP and PE diets. The observed modifications of faecal microbioma were related not only to the change from RD to CP or PE, but also to the type of pulse, chickpeas or peas. However, long-term studies are required to investigate the implications that pulses can have for gut health
Temperature dependence of the thermal boundary resistivity of glass-embedded metal nanoparticles
The temperature dependence of the thermal boundary resistivity is
investigated in glass-embedded Ag particles of radius 4.5 nm, in the
temperature range from 300 to 70 K, using all-optical time-resolved
nanocalorimetry. The present results provide a benchmark for theories aiming at
explaining the thermal boundary resistivity at the interface between metal
nanoparticles and their environment, a topic of great relevance when tailoring
thermal energy delivery from nanoparticles as for applications in nanomedicine
and thermal management at the nanoscaleComment: 4 pages, 3 figure
Flame pyrolysis synthesis of mixed oxides for glycerol steam reforming
Flame spray pyrolysis was used to produce nanosized Ni-based catalysts starting from different mixed oxides. LaNiO3 and CeNiO3 were used as base materials and the formulation was varied by mixing them or incorporating variable amounts of ZrO2 or SrO during the synthesis. The catalysts were tested for the steam reforming of glycerol. One of the key problems for this application is the resistance to deactivation by sintering and coking, which may be increased by (1) improving Ni dispersion through the production of a Ni-La or Ni-Ce mixed oxide precursor, and then reduced; (2) using an oxide as ZrO2, which established a strong interaction with Ni and possesses high thermal resistance; (3) decreasing the surface acidity of ZrO2 through a basic promoter/support, such as La2O3; and (4) adding a promoter/support with very high oxygen mobility such as CeO2. A further key feature is the use of a high temperature synthesis, such as flame spray pyrolysis, to improve the overall thermal resistance of the oxides. These strategies proved effective to obtain active and stable catalysts at least for 20 h on stream with very limited coke formation
Trends and risk factors for syphilis infection in Piedmont Region, Italy, 2002-2008
Background: This work aims to analyze trends of syphilis infections in the Piedmont Region (Italy) between
2002 and 2008, and to evaluate risk factors for infection.
Methods: Syphilis trends were described according to socio-demographic characteristics, sexual behavior,
condom use, number of partners and HIV infection. Independent risk factors for syphilis among men having
sex with men (MSM), men having sex with women (MSW), and women were identified through logistic
regression comparing cases with 12,773 negative patients.
Results: Between 2002 and 2008, 1,046 cases of syphilis were diagnosed, with peaks in 2004 and 2007. The
risk of a syphilis diagnosis was independently associated with being older than 24, having a low education
level, homosexual behavior, HIV self-reported infection (for MSM and MSW), number of partners (for MSW
and women) and non- consistent condom use (for women).
Conclusions: Recent outbreaks suggest that the attention to syphilis can’t be lowered. Screening, treatment
of cases and notification of partners should be reinforced and integrated with sexual health education and
counselling in high-risk environments. Surveillance data must be continuously collected
Laser-driven quantum magnonics and THz dynamics of the order parameter in antiferromagnets
The impulsive generation of two-magnon modes in antiferromagnets by
femtosecond optical pulses, so-called femto-nanomagnons, leads to coherent
longitudinal oscillations of the antiferromagnetic order parameter that cannot
be described by a thermodynamic Landau-Lifshitz approach. We argue that this
dynamics is triggered as a result of a laser-induced modification of the
exchange interaction. In order to describe the oscillations we have formulated
a quantum mechanical description in terms of magnon pair operators and coherent
states. Such an approach allowed us to} derive an effective macroscopic
equation of motion for the temporal evolution of the antiferromagnetic order
parameter. An implication of the latter is that the photo-induced spin dynamics
represents a macroscopic entanglement of pairs of magnons with femtosecond
period and nanometer wavelength. By performing magneto-optical pump-probe
experiments with 10 femtosecond resolution in the cubic KNiF and the
uniaxial KNiF collinear Heisenberg antiferromagnets, we observed
coherent oscillations at the frequency of 22 THz and 16 THz, respectively. The
detected frequencies as a function of the temperature ideally fit the
two-magnon excitation up to the N\'eel point. The experimental signals are
described as dynamics of magnetic linear dichroism due to longitudinal
oscillations of the antiferromagnetic vector.Comment: 25 pages, 10 figure
Ultrafast Spectroscopy of Graphene-Protected Thin Copper Films
© 2016 American Chemical Society. We studied by broad-band pump-probe spectroscopy the ultrafast optical response of thin copper films covered by a monolayer of graphene. It is demonstrated that graphene protection does not alter the thermo-modulational nonlinearity of copper in the whole visible range. Also, we provide a quantitative validation of a theoretical model for this optical nonlinearity, derived from a semiclassical description of electron thermalization dynamics and subsequent modulation of copper dielectric function from 450 to 700 nm wavelength. Our results extend to the nonlinear domain the capability of graphene-protected copper nanolayers to serve as a low cost optical grade material, with major potential impact on nonlinear plasmonics and metamaterials
Femtosecond phononic coupling to both spins and charges in a room-temperature antiferromagnetic semiconductor
Spintronics is postulated on the possibility to employ the magnetic degree of freedom of electrons for computation and couple it to charges. In this view the combination of the high frequency of spin manipulations offered
by antiferromagnets, with the wide tunability of the electronic properties peculiar of semiconductors, provides
a promising and intriguing platform. Here we explore this scenario in α-MnTe, which is a semiconductor
antiferromagnetically ordered at room temperature. Relying on a Raman mechanism and femtosecond laser
pulses, we drive degenerate modes of coherent optical phonons, which modulate the chemical bonds involved
in the superexchange interaction. The spectrally resolved measurements of the transient reflectivity reveal a
coherent modulation of the band gap at the frequency of 5.3 THz. The detection of the rotation of the polarization,
typically associated with magneto-optical effects, shows coherent and incoherent contributions. Modeling how
the ionic motion induced by the phonons affects the exchange interaction in the material, we calculate the
photoinduced THz spin dynamics: the results predict both a coherent and incoherent response, the latter of which
is consistent with the experimental observation. Our work demonstrates that the same phonon modes modulate
both the charge and magnetic degree of freedom, suggesting the resonant pumping of phonons as a viable way
to link spin and charge dynamics even in nonlinear regimes
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