102 research outputs found
Circulating endothelial progenitor cells and large artery structure and function in young subjects with uncomplicated Type 1 Diabetes
<p>Abstract</p> <p>Background</p> <p>Carotid intima-media thickness (IMT), indices of large artery stiffness and measures of endothelium function may be used as markers of early atherosclerosis in type 1 diabetes mellitus (T1DM). The aim of the present study was to compare the indices of large artery structure and function as well as endothelial function and regenerating capacity between adolescents with T1DM and healthy control of similar age. In addition, the associations of different vascular measures with endothelial progenitor cells (EPCs), glyco-metabolic control and serum levels of advanced glycation endproducts (AGEs), soluble receptors for AGEs (sRAGE) and adiponectin were evaluated.</p> <p>Methods</p> <p>Sixteen uncomplicated young T1DM patients (mean age 18 ± 2 years, history of disease 11 ± 5 years, HbA1c 7.7 ± 1.1%) and 26 controls (mean age 19 ± 2 years) were studied. A radiofrequency-based ultrasound system (Esaote MyLab 70) was used to measure carotid IMT and wave speed (WS, index of local stiffness), applanation tonometry (PulsePen) was applied to obtain central pulse pressure (PP) and augmentation index (AIx), and carotid-femoral pulse wave velocity (PWV, Complior) was used as index of aortic stiffness. Peripheral endothelium-dependent vasodilation was determined as reactive hyperemia index (RHI, EndoPAT). Circulating EPCs, glycometabolic profile, AGEs (autofluorescence method), sRAGE and adiponectin were also measured.</p> <p>Results</p> <p>After adjusting for age, sex and blood pressure, T1DM adolescents had significantly higher carotid IMT (456 ± 7 vs. 395 ± 63 μm, p < 0.005), carotid WS (p < 0.005), PWV (p = 0.01), AIx (p < 0.0001) and central PP (p < 0.01) and lower EPCs (p = 0.02) as compared to controls. RHI was reduced only in diabetic patients with HbA1c ≥7.5% (p < 0.05). In the overall population, EPCs were an independent determinant of carotid IMT (together with adiponectin), while fasting plasma glucose was an independent determinant of carotid WS, AIx and central PP.</p> <p>Conclusions</p> <p>Our findings suggest that young subjects with relatively long-lasting T1DM have a generalized preclinical involvement of large artery structure and function, as well as a blunted endothelium regenerating capacity. Hyperglycemia and suboptimal chronic glycemic control seem to deteriorate the functional arterial characteristics, such as large arteries stiffness, wave reflection and peripheral endothelium-dependent vasodilation, whereas an impaired endothelium regenerating capacity and adiponectin levels seem to influence arterial structure.</p
Transplastomic tobacco plants expressing a fatty acid desaturase gene exhibit altered fatty acid profiles and improved cold tolerance
The possibility of altering the unsaturation
level of fatty acids in plant lipids by genetic transformation
has implications for the stress tolerance of
higher plants as well as for their nutritional value and
industrial utilisation. While the integration and expression
of transgenes in the plastome has several potential
advantages over nuclear transformation, very few
attempts have been made to manipulate fatty acid
biosynthesis using plastid transformation. We produced
transplastomic tobacco plants that express a Delta9
desaturase gene from either the wild potato species
Solanum commersonii or the cyanobacterium Anacystis
nidulans, using PEG-mediated DNA uptake by protoplasts. Incorporation of chloroplast antibioticinsensitive
point mutations in the transforming DNA
was used to select transformants. The presence of the
transcript and the Delta9 desaturase protein in transplastomic
plants was confirmed by northern and western
blot analyses. In comparison with control plants,
transplastomic plants showed altered fatty acid profiles
and an increase in their unsaturation level both in leaves
and seeds. The two transgenes produced comparable
results. The results obtained demonstrate the feasibility
of using plastid transformation to engineer lipid
metabolic pathways in both vegetative and reproductive
tissues and suggest an increase of cold tolerance in
transplastomic plants showing altered leaf fatty acid
profiles. This is the first example of transplastomic
plants expressing an agronomically relevant gene
produced with the ‘‘binding-type’’ vectors, which do
not contain a heterologous marker gene. In fact, the
transplastomic plants expressing the S. commersonii
gene contain only plant-derived sequences, a clear
attraction from a public acceptability perspective
Mass testing of the JUNO experiment 20-inch PMTs readout electronics
The Jiangmen Underground Neutrino Observatory (JUNO) is a multi-purpose,
large size, liquid scintillator experiment under construction in China. JUNO
will perform leading measurements detecting neutrinos from different sources
(reactor, terrestrial and astrophysical neutrinos) covering a wide energy range
(from 200 keV to several GeV). This paper focuses on the design and development
of a test protocol for the 20-inch PMT underwater readout electronics,
performed in parallel to the mass production line. In a time period of about
ten months, a total number of 6950 electronic boards were tested with an
acceptance yield of 99.1%
Implementation and performances of the IPbus protocol for the JUNO Large-PMT readout electronics
The Jiangmen Underground Neutrino Observatory (JUNO) is a large neutrino
detector currently under construction in China. Thanks to the tight
requirements on its optical and radio-purity properties, it will be able to
perform leading measurements detecting terrestrial and astrophysical neutrinos
in a wide energy range from tens of keV to hundreds of MeV. A key requirement
for the success of the experiment is an unprecedented 3% energy resolution,
guaranteed by its large active mass (20 kton) and the use of more than 20,000
20-inch photo-multiplier tubes (PMTs) acquired by high-speed, high-resolution
sampling electronics located very close to the PMTs. As the Front-End and
Read-Out electronics is expected to continuously run underwater for 30 years, a
reliable readout acquisition system capable of handling the timestamped data
stream coming from the Large-PMTs and permitting to simultaneously monitor and
operate remotely the inaccessible electronics had to be developed. In this
contribution, the firmware and hardware implementation of the IPbus based
readout protocol will be presented, together with the performances measured on
final modules during the mass production of the electronics
Validation and integration tests of the JUNO 20-inch PMTs readout electronics
The Jiangmen Underground Neutrino Observatory (JUNO) is a large neutrino
detector currently under construction in China. JUNO will be able to study the
neutrino mass ordering and to perform leading measurements detecting
terrestrial and astrophysical neutrinos in a wide energy range, spanning from
200 keV to several GeV. Given the ambitious physics goals of JUNO, the
electronic system has to meet specific tight requirements, and a thorough
characterization is required. The present paper describes the tests performed
on the readout modules to measure their performances.Comment: 20 pages, 13 figure
First results on the angular resolution of the ARGO-YBJ detector
We present the first results on the angular resolution of the ARGO-YBJ detector in data taking at the Yangbajing Laboratory (Tibet, P.R. China, 4300 m a.s.l.
Simulation study of air shower particles near the core region
The ARGO-YBJ experiment has two kinds of signals in the shower working mode which allows coverage of the energy region from TeV to PeV region. One is the digital strip pattern, another is so-called ‘big pad’ mode, which is the analog signal counting the pulse height on half of an RPC, proportional to the number of hitting particles. In this paper by using the Monte Carlo simulation method the ARGO-YBJ sensitivity to the cosmic ray composition is discussed, by using the ‘big pad’ signal for measuring the number of particles detected close to the shower core
Search for gamma ray bursts with the ARGO-YBJ detector in scaler mode
The ARGO-YBJ experiment has been designed to decrease the energy threshold of typical Extensive Air Shower arrays by exploiting the high altitude and the full coverage, consisting of a 6700m2 carpet of Resistive Plate Chambers located at Yangbajing (Tibet, PR China, 4300m a.s.l.). The lower energy limit of the detector (1 GeV) is reached with the ‘‘Scaler Mode’’, recording the counting rate at fixed time intervals. Here we present results concerning the search for emission from Gamma Ray Bursts (GRBs) in coincidence with satellite detections
Potential of Core-Collapse Supernova Neutrino Detection at JUNO
JUNO is an underground neutrino observatory under construction in Jiangmen, China. It uses 20kton liquid scintillator as target, which enables it to detect supernova burst neutrinos of a large statistics for the next galactic core-collapse supernova (CCSN) and also pre-supernova neutrinos from the nearby CCSN progenitors. All flavors of supernova burst neutrinos can be detected by JUNO via several interaction channels, including inverse beta decay, elastic scattering on electron and proton, interactions on C12 nuclei, etc. This retains the possibility for JUNO to reconstruct the energy spectra of supernova burst neutrinos of all flavors. The real time monitoring systems based on FPGA and DAQ are under development in JUNO, which allow prompt alert and trigger-less data acquisition of CCSN events. The alert performances of both monitoring systems have been thoroughly studied using simulations. Moreover, once a CCSN is tagged, the system can give fast characterizations, such as directionality and light curve
Detection of the Diffuse Supernova Neutrino Background with JUNO
As an underground multi-purpose neutrino detector with 20 kton liquid scintillator, Jiangmen Underground Neutrino Observatory (JUNO) is competitive with and complementary to the water-Cherenkov detectors on the search for the diffuse supernova neutrino background (DSNB). Typical supernova models predict 2-4 events per year within the optimal observation window in the JUNO detector. The dominant background is from the neutral-current (NC) interaction of atmospheric neutrinos with 12C nuclei, which surpasses the DSNB by more than one order of magnitude. We evaluated the systematic uncertainty of NC background from the spread of a variety of data-driven models and further developed a method to determine NC background within 15\% with {\it{in}} {\it{situ}} measurements after ten years of running. Besides, the NC-like backgrounds can be effectively suppressed by the intrinsic pulse-shape discrimination (PSD) capabilities of liquid scintillators. In this talk, I will present in detail the improvements on NC background uncertainty evaluation, PSD discriminator development, and finally, the potential of DSNB sensitivity in JUNO
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