254 research outputs found
Thermoplasmonic effect of surface enhanced infrared absorption in vertical nanoantenna arrays
Thermoplasmonics is a method for increasing temperature remotely using focused visible or infrared laser beams interacting with plasmonic nanoparticles. Here, local heating induced by mid-infrared quantum cascade laser illumination of vertical gold-coated nanoantenna arrays embedded into polymer layers is investigated by infrared nanospectroscopy and electromagnetic/thermal simulations. Nanoscale thermal hotspot images are obtained by a photothermal scanning probe microscopy technique with laser illumination wavelength tuned at the different plasmonic resonances of the arrays. Spectral analysis indicates that both Joule heating by the metal antennas and surface-enhanced infrared absorption (SEIRA) by the polymer molecules located in the apical hotspots of the antennas are responsible for thermoplasmonic resonances, i.e. for strong local temperature increase. At odds with more conventional planar nanoantennas, the vertical antenna structure enables thermal decoupling of the hotspot at the antenna apex from the heat sink constituted by the solid substrate. The temperature increase was evaluated by quantitative comparison of data obtained with the photothermal expansion technique to the results of electromagnetic/ thermal simulations. In the case of strong SEIRA by the C=O bond of poly-methylmethacrylate at 1730 cm-1, for focused mid-infrared laser power of about 20 mW, the evaluated order of magnitude of the nanoscale temperature increase is of 10 K. This result indicates that temperature increases of the order of hundreds of K may be attainable with full mid-infrared laser power tuned at specific molecule vibrational fingerprints
Thermoplasmonic effect of surface enhanced infrared absorption in vertical nanoantenna arrays
Thermoplasmonics is a method for increasing temperature remotely using focused visible or infrared laser beams interacting with plasmonic nanoparticles. Here, local heating induced by mid-infrared quantum cascade laser illumination of vertical gold-coated nanoantenna arrays embedded into polymer layers is investigated by infrared nanospectroscopy and electromagnetic/thermal simulations. Nanoscale thermal hotspot images are obtained by a photothermal scanning probe microscopy technique with laser illumination wavelength tuned at the different plasmonic resonances of the arrays. Spectral analysis indicates that both Joule heating by the metal antennas and surface-enhanced infrared absorption (SEIRA) by the polymer molecules located in the apical hotspots of the antennas are responsible for thermoplasmonic resonances, i.e. for strong local temperature increase. At odds with more conventional planar nanoantennas, the vertical antenna structure enables thermal decoupling of the hotspot at the antenna apex from the heat sink constituted by the solid substrate. The temperature increase was evaluated by quantitative comparison of data obtained with the photothermal expansion technique to the results of electromagnetic/ thermal simulations. In the case of strong SEIRA by the C=O bond of poly-methylmethacrylate at 1730 cm-1, for focused mid-infrared laser power of about 20 mW, the evaluated order of magnitude of the nanoscale temperature increase is of 10 K. This result indicates that temperature increases of the order of hundreds of K may be attainable with full mid-infrared laser power tuned at specific molecule vibrational fingerprints
First report of Leucostoma cinctum on sweet cherry and European plum in Italy
Leucostoma cinctum and L. persoonii are the two species involved in Leucostoma canker, a disease that causes dieback of twigs and branches, bark cankers, gummosis, and tree decline of stone fruit. The aim of this study was to identify the causal agent of Leucostoma canker in Italian stone fruit orchards. More than 200 isolates of Leucostoma spp. were obtained from branches and twigs of sweet and sour cherry, apricot, and European plum trees that showed typical symptoms of Leucostoma canker. These trees were in commercial orchards of two Italian regions, Marche and Apulia, in central-eastern and south-eastern Italy, respectively. Soon after isolation, all of the colonies that grew on potato dextrose agar were white in colour, and after about 10 d they became olive-green. Growth was not observed at 33°C, and the pycnidia were larger than 1 mm diam. This information led to the identification of L. cinctum as the causal agent of these Leucostoma cankers. To our knowledge, this is the first report of L. cinctum on sweet cherry and European plum in Italy
Pre-frontal Cortical Activity During Walking and Turning Is Reliable and Differentiates Across Young, Older Adults and People With Parkinson's Disease
Introduction: Mobility declines with age and further with neurodegenerative disorders, such as Parkinson's disease (PD). Walking and turning ability, in particular, are vital aspects of mobility that deteriorate with age and are further impaired in PD. Such deficits have been linked with reduction in automatic control of movement and the need for compensatory cognitive cortical control via the pre-frontal cortex (PFC), however the underlying neural mechanisms remain unclear. Establishing and using a robust methodology to examine PFC activity during continuous walking and turning via mobile functional near infra-red spectroscopy (fNIRS) may aid in the understanding of mobility deficits and help with development of appropriate therapeutics.This study aimed to: (1) examine test re-test reliability of PFC activity during continuous turning and walking via fNIRS measurement; and (2) compare PFC activity during continuous turning and walking in young, old and Parkinson's subjects.Methods: Twenty-five young (32.3 ± 7.5 years), nineteen older (65.4 ± 7.0 years), and twenty-four PD (69.3 ± 4.1 years) participants performed continuous walking and 360° turning-in-place tasks, each lasting 2 min. Young participants repeated the tasks a second time to allow fNIRS measurement reliability assessment. The primary outcome was PFC activity, assessed via measuring changes in oxygenated hemoglobin (HbO2) concentrations.Results: PFC activity during continuous walking and turning was moderately reproducible (Intra-class correlation coefficient = 0.67). The PD group had higher PFC activation than young and older adults during walking and turning, with significant group differences for bilateral PFC activation (p = 0.025), left PFC activation (p = 0.012), and the early period (first 40 s) of walking (p = 0.007), with greater activation required in PD. Interestingly, older adults had similar PFC activation to young adults across conditions, however older adults required greater activation than young adults during continuous turning, specifically the early period of the turning task (Cohens d = 0.86).Conclusions: PFC activity can be measured during continuous walking and turning tasks with acceptable reliability, and can differentiate young, older and PD groups. PFC activation was significantly greater in PD compared to young and older adults during walking, particularly when beginning to walk
Morphological and Molecular Identification of Seedborne Fungi in Squash (Cucurbita maxima, Cucurbita moschata).
Squash is one of the most important crops of tropical and temperate regions, and it can be affected by several fungal pathogens. Most of these pathogens infect the seeds, which become an efficient vehicle to disperse seedborne pathogens over long distances, with consequent severe crop losses. The main objective of this study was the identification of the principal seedborne fungi in seeds extracted from 66 samples of asymptomatic and symptomatic squash fruit (Cucurbita maxima, Cucurbita moschata) collected in two countries, Tunisia and Italy. The symptoms of fruit decay were identified and classified according to lesion size. Following the blotter test, 14 fungal species were detected from the seeds. Seedborne fungi were identified in all fruit samples tested, including asymptomatic fruit. The most frequent fungi from Tunisian seeds were Alternaria alternata (25.1%), followed by Stagonosporopsis cucurbitacearum (24.6%), Fusarium solani (16.6%), Rhizopus stolonifer (13.3%), F. fujikuroi (7.8%), Albifimbria verrucaria (3.3%), and Stemphylium vesicarium (2.3%). For the fruits from Italy, the most frequently identified fungal species in seed samples were Alternaria alternata (40.0%), followed by F. fujikuroi (20.8%), Stemphylium vesicarium (3.0%), and Curvularia spicifera (2.1%). Morphological identification was confirmed by molecular diagnosis using the available species-specific primers. Furthermore, specific primers were designed to identify Albifimbria verrucaria, Paramyrothecium roridum, and Stemphylium vesicarium. Application of seed-health testing methods, including such conventional and molecular diagnostic tools, will help to improve seed quality and crop yields
Thermoplasmonic Effect of Surface Enhanced Infrared Absorption in Vertical Nanoantenna Arrays
The temperature increase and temperature gradients induced by mid-infrared
laser illumination of vertical gold nanoantenna arrays embedded into polymer
layers was measured directly with a photothermal expansion nanoscope. Nanoscale
thermal hotspot images and local temperature increase spectra were both
obtained, the latter by broadly tuning the emission wavelength of a quantum
cascade laser. The spectral analysis indicates that plasmon-enhanced
mid-infrared vibrations of molecules located in the antenna hotspots are
responsible for some of the thermoplasmonic resonances, while Joule heating in
gold is responsible for the remaining resonances. In particular, plasmonic dark
modes with low scattering cross-section mostly produce surface-enhanced
infrared absorption (SEIRA), while bright modes with strong radiation coupling
produce Joule heating. The dark modes do not modify the molecular absorption
lineshape and the related temperature increase is chemically triggered by the
presence of molecules with vibrational fingerprints resonant with the plasmonic
dark modes. The bright modes, instead, are prone to Fano interference, display
an asymmetric molecular absorption lineshape and generate heat also at
frequencies far from molecular vibrations, insofar lacking chemical
specificity. For focused mid-infrared laser power of 50 mW, the measured
nanoscale temperature increases are in the range of 10 K and temperature
gradients reach 5 K/m in the case of dark modes resonating with strong
infrared vibrations such as the C=O bond of poly-methylmethacrylate at 1730
cm.Comment: 17 pages, 4 figure
Gametocytes of the Malaria Parasite Plasmodium falciparum Interact With and Stimulate Bone Marrow Mesenchymal Cells to Secrete Angiogenetic Factors
The gametocytes of Plasmodium falciparum, responsible for the
transmission of this malaria parasite from humans to mosquitoes,
accumulate and mature preferentially in the human bone marrow.
In the 10 day long sexual development of P. falciparum, the
immature gametocytes reach and localize in the extravascular
compartment of this organ, in contact with several bone marrow
stroma cell types, prior to traversing the endothelial lining
and re-entering in circulation at maturity. To investigate the
host parasite interplay underlying this still obscure process,
we developed an in vitro tridimensional co-culture system in a
Matrigel scaffold with P. falciparum gametocytes and
self-assembling spheroids of human bone marrow mesenchymal cells
(hBM-MSCs). Here we show that this co-culture system sustains
the full maturation of the gametocytes and that the immature,
but not the mature, gametocytes adhere to hBM-MSCs via
trypsin-sensitive parasite ligands exposed on the erythrocyte
surface. Analysis of a time course of gametocytogenesis in the
co-culture system revealed that gametocyte maturation is
accompanied by the parasite induced stimulation of hBM-MSCs to
secrete a panel of 14 cytokines and growth factors, 13 of which
have been described to play a role in angiogenesis. Functional
in vitro assays on human bone marrow endothelial cells showed
that supernatants from the gametocyte mesenchymal cell
co-culture system enhance ability of endothelial cells to form
vascular tubes. These results altogether suggest that the
interplay between immature gametocytes and hBM-MSCs may induce
functional and structural alterations in the endothelial lining
of the human bone marrow hosting the P. falciparum transmission
stages
Prevalence, sensitivity and specificity of antibodies against carbamylated proteins in a monocentric cohort of patients with rheumatoid arthritis and other autoimmune rheumatic diseases
Antibodies against carbamylated proteins (anti-CarP) have been recently identified in the sera of patients with rheumatoid arthritis (RA). The objective of the study was to evaluate the prevalence, sensitivity and specificity of anti-CarP compared to anti-citrullinated peptide antibodies (ACPA) and rheumatoid factor (RF), replicating the existing data in a large cohort of Italian patients with RA and extending the evaluation to other autoimmune rheumatic diseases (AIRDs)
Possible antiviral effect of ciprofloxacin treatment on polyomavirus BK replication and analysis of non-coding control region sequences
Acute renal dysfunction (ARD) is a common complication in renal transplant recipients. Multiple factors contribute to ARD development, including acute rejection and microbial infections. Many viral infections after kidney transplantation result from reactivation of “latent” viruses in the host or from the graft, such as the human Polyomavirus BK (BKV). We report the case of a 39 year-old recipient of a 2(nd) kidney graft who experienced BKV reactivation after a second episode of acute humoral rejection. A 10-day treatment with the quinolone antibiotic ciprofloxacin was administered with an increase of immunosuppressive therapy despite the active BKV replication. Real Time PCR analysis performed after treatment with ciprofloxacin, unexpectedly showed clearance of BK viremia and regression of BK viruria. During the follow-up, BK viremia persisted undetectable while viruria decreased further and disappeared after 3 months. BKV non-coding control region sequence analysis from all positive samples always showed the presence of archetypal sequences, with two single-nucleotide substitutions and one nucleotide deletion that, interestingly, were all representative of the subtype/subgroup I/b-1 we identified by the viral protein 1 sequencing analysis. We report the potential effect of the quinolone antibiotic ciprofloxacin in the decrease of the BKV load in both blood and urine
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