7,626 research outputs found
In situ polymerization of soil organic matter by oxidative biomimetic catalysis.
Background: Agricultural practices that enhance organic matter content in soil can play a central role in sequestering soil organic carbon (SOC) and reducing greenhouse gases emissions. Methods: We used a water-soluble iron-porphyrin to catalyze directly in situ oxidative polymerization of soil organic matter in the presence of H2O2 oxidant, with the aim to enhance OC stabilization, and, consequently, reduce CO2 emissions from soil. The occurred SOC stabilization was assessed by monitoring soil aggregate stability, OC distribution in water-soluble aggregates, soil respiration, and extraction yields of humic and fulvic acids. Results: Soil treatment with H2O2 and iron-porphyrin increased the physical stability of water-stable soil aggregates and the total OC content in small aggregates, thereby suggesting that the catalyzed oxidative polymerization increased OC in soil and induced a soil physical improvement. The significant reduction of CO2 respired by the catalyst- and H2O2-treated soil indicated an enhanced resistance of polymerized SOC to microbial mineralization. The catalyzed oxidative polymerization of SOC also significantly decreased the extraction yields of humic and fulvic acids from soil. Conclusions: The oxidative catalytic technology described here may become an efficient agricultural practice for OC sequestration in soils and contribute to mitigate global changes
Micro-optical Tandem Luminescent Solar Concentrators
Traditional concentrating photovoltaic (CPV) systems utilize multijunction
cells to minimize thermalization losses, but cannot efficiently capture diffuse
sunlight, which contributes to a high levelized cost of energy (LCOE) and
limits their use to geographical regions with high direct sunlight insolation.
Luminescent solar concentrators (LSCs) harness light generated by luminophores
embedded in a light-trapping waveguide to concentrate light onto smaller cells.
LSCs can absorb both direct and diffuse sunlight, and thus can operate as flat
plate receivers at a fixed tilt and with a conventional module form factor.
However, current LSCs experience significant power loss through parasitic
luminophore absorption and incomplete light trapping by the optical waveguide.
Here we introduce a tandem LSC device architecture that overcomes both of these
limitations, consisting of a PLMA polymer layer with embedded CdSe/CdS quantum
dot (QD) luminophores and InGaP micro-cells, which serve as a high bandgap
absorber on top of a conventional Si photovoltaic. We experimentally synthesize
CdSe/CdS QDs with exceptionally high quantum-yield (99%) and ultra-narrowband
emission optimally matched to fabricated III-V InGaP micro-cells. Using a Monte
Carlo ray-tracing model, we show the radiative limit power conversion
efficiency for a module with these components to be 30.8% diffuse sunlight
conditions. These results indicate that a tandem LSC-on-Si architecture could
significantly improve upon the efficiency of a conventional Si photovoltaic
module with simple and straightforward alterations of the module lamination
steps of a Si photovoltaic manufacturing process, with promise for widespread
module deployment across diverse geographical regions and energy markets
AC losses reduction in Hairpin Windings produced via Additive Manufacturing
One of the key challenges of hairpin windings is the reduction of their high losses at high-frequency operations. Hairpin layouts comprising conductors with variable cross sections have proven good loss performance in previous studies. However, they come at the cost of significant manufacturing complications.
The aim of this work is to design hairpin layouts featuring reduced losses compared to classical configurations, exploiting the flexibility enabled by additive manufacturing. In this context, the choice of a proper material with relatively high conductivity and low ecological impact plays an important role. Hence, this article first presents an overview of materials that can be used for the winding additive manufacturing, aiming to select the most suitable one for the application at hand. Then, the loss performance is evaluated and compared against classical copper hairpins. The results demonstrate that opportunely selected alloys featuring asymmetric configurations can compete against classical hairpin windings.
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Transforming growth factor β1 T29C gene polymorphism and hypertension: Relationship with cardiovascular and renal damage
Distribution of T29C TGFβ1 gene polymorphism was analysed in 260 hypertensive and 134 normotensive subjects. Circulating TGFβ1 and procollagen type III levels, microalbuminuria, left ventricular geometry and function were evaluated in all the hypertensives subgrouped according to T29C TGFβ1 gene polymorphism. Circulating TGFβ1 by ELISA technique, procollagen type III by a specific radioimmunoassay, microalbuminuria by radioimmunoassay, left ventricular geometry and function by echocardiography were determined. All groups were comparable for gender, age and sex. Regarding T29C TGFβ1 gene polymorphism, prevalence of TC or CC genotypes was significantly (p < 0.05) higher in hypertensives than normotensives. TC and CC hypertensives were characterized by a higher prevalence of subjects with microalbuminuria (p < 0.001 TC vs TT; p < 0.05 CC vs TT), left ventricular hypertrophy (p < 0.01 TC and CC vs TT), and by increased levels of procollagen type III (p < 0.05 TC and CC vs TT). TC hypertensives were also characterized by a significant increase (p < 0.05) of LVM and LVM/h2.7 and of urinary albumin excretion (p < 0.05) values than those detectable in TT hypertensives. Our data suggest that T29C TGFβ1 gene polymorphism was associated to clinical characteristics suitable to recognize hypertensives with a higher severity of hypertension
Misdiagnosis of familial Mediterranean fever in patients with Anderson-Fabry disease
Fabry disease (FD) is an underdiagnosed pathology due to its symptomatology that
overlaps with various systemic and rheumatic disorders, including familial
Mediterranean fever (FMF). We examined the Mediterranean fever (MEFV) and
α-galactosidase A (GLA) genes, whose mutations are responsible for FMF and FD,
respectively, in 42 unrelated patients diagnosed with FMF, which revealed
significant ambiguity regarding some of the symptoms which are also present in
FD. The objective of this study was to determine the spectrum of mutations
present in these genes, in order to identify cases of mistaken diagnosis of FMF
and/or missed diagnosis of FD. Ten out of 42 patients had one mutation in
homozygosis or two different mutations in heterozygosis in the MEFV gene; 20/42
had a single heterozygous mutation, and 12/42 did not have genetic alterations in
MEFV. The analysis of the GLA gene conducted on all the samples revealed that
three subjects, and some members of their families, had two different exonic
mutations associated with FD. Family studies allowed us to identify eight other
cases of FD, bringing the total undiagnosed subjects to 11/53. Analyzing the MEFV
and GLA genes in patients with clinical diagnoses of FMF proved to be
fundamentally important for the reduction of diagnostic errors
A study of gas contaminants and interaction with materials in RPC closed loop systems
Resistive Plate Counters (RPC) detectors at the Large Hadron Collider (LHC)
experiments use gas recirculation systems to cope with large gas mixture
volumes and costs. In this paper a long-term systematic study about gas
purifiers, gas contaminants and detector performance is discussed. The study
aims at measuring the lifetime of purifiers with unused and used cartridge
material along with contaminants release in the gas system. During the
data-taking the response of several RPC double-gap detectors was monitored in
order to characterize the correlation between dark currents, filter status and
gas contaminants
Flavonoids in Lemon and Grapefruit IntegroPectin**
Following the analysis of terpenes present in new lemon and grapefruit “IntegroPectin” pectins obtained via the hydrodynamic cavitation of industrial lemon and grapefruit processing waste, the HPLC-MS analysis of flavonoid and other phenolic compounds reveals the presence of eriocitrin, naringin, hesperidin and kaempferol typical of the respective citrus fruits. The pectic fibers rich in rhamnogalacturonan-I regions act as chemical sponges adsorbing and concentrating at their outer surface highly bioactive citrus flavonoids and terpenes. These findings, together with the unique molecular structure of these new whole citrus pectins, provide preliminary insight into the broad-scope biological activity of these new biomaterials. Numerous new biomedical applications are anticipated, including likely use in the prevention and treatment of microbial infections and neurodegenerative disease
Gas Analysis and Monitoring Systems for the RPC Detector of CMS at LHC
The Resistive Plate Chambers (RPC) detector of the CMS experiment at the LHC
proton collider (CERN, Switzerland) will employ an online gas analysis and
monitoring system of the freon-based gas mixture used. We give an overview of
the CMS RPC gas system, describe the project parameters and first results on
gas-chromatograph analysis. Finally, we report on preliminary results for a set
of monitor RPC.Comment: 9 pages, 8 figures. Presented by Stefano Bianco (Laboratori Nazionali
di Frascati dell'INFN) at the IEEE NSS, San Diego (USA), October 200
Studia Lichenologica in Italy. I. New records of red-listed species
We present new data concerning lichen species of the Italian flora and confirm 36 national redlisted species
EP-1425: Phase I study on hypofractionated accelerated radiotherapy for bone metastases from prostate cancer
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