A
bstract
The NEXT experiment aims at the sensitive search of the neutrinoless double beta decay in
136
Xe, using high-pressure gas electroluminescent time projection chambers. The NEXT-White ...detector is the first radiopure demonstrator of this technology, operated in the Laboratorio Subterráneo de Canfranc. Achieving an energy resolution of 1% FWHM at 2.6 MeV and further background rejection by means of the topology of the reconstructed tracks, NEXT-White has been exploited beyond its original goals in order to perform a neu- trinoless double beta decay search. The analysis considers the combination of 271.6 days of
136
Xe-enriched data and 208.9 days of
136
Xe-depleted data. A detailed background modeling and measurement has been developed, ensuring the time stability of the radiogenic and cosmogenic contributions across both data samples. Limits to the neutrinoless mode are obtained in two alternative analyses: a background-model-dependent approach and a novel direct background-subtraction technique, offering results with small dependence on the background model assumptions. With a fiducial mass of only 3.50 ± 0.01 kg of
136
Xe-enriched xenon, 90% C.L. lower limits to the neutrinoless double beta decay are found in the
T
1
/
2
0
ν
> 5
.
5
×
10
23
−
1
.
3
×
10
24
yr range, depending on the method. The presented techniques stand as a proof-of-concept for the searches to be implemented with larger NEXT detectors.
(1) Background: Pulmonary endarterectomy (PEA) is the "gold standard" treatment for operable patients with chronic thromboembolic pulmonary hypertension (CTEPH). Persistent pulmonary hypertension ...(PH) after PEA confers a worse prognosis. Balloon pulmonary angioplasty (BPA) could represent a useful therapy in this setting, but evidence about its effectiveness and safety in patients with previous PEA is limited. (2) Methods: A total of 14 patients with persistent PH after PEA were treated with BPA in a single PH center. Hemodynamic and clinical effects of BPA and complications of the procedure were retrospectively collected. (3) Results: After BPA, the mean pulmonary arterial pressure fell from 50.7 ± 15.3 mmHg to 38.0 ± 7.9 mmHg (25.0% decrease; 95% confidence interval (CI) 14.0-35.5%;
= 0.01). Pulmonary vascular resistances were reduced from 8.5 ± 3.6 WU to 5.3 ± 2.2 WU (37.6% decrease; 95% CI 18.8-56.5%;
= 0.01). WHO functional class was also improved with BPA. Severe BPA-related complications were infrequent and no periprocedural deaths were observed. (4) Conclusions: BPA is an effective and safe therapy for patients with CTEPH and persistent PH after PEA.
Abstract
The search for neutrinoless double beta decay (0
νββ
) remains one of the most compelling experimental avenues for the discovery in the neutrino sector. Electroluminescent gas-phase time ...projection chambers are well suited to 0
νββ
searches due to their intrinsically precise energy resolution and topological event identification capabilities. Scalability to ton- and multi-ton masses requires readout of large-area electroluminescent regions with fine spatial resolution, low radiogenic backgrounds, and a scalable data acquisition system. This paper presents a detector prototype that records event topology in an electroluminescent xenon gas TPC via VUV image-intensified cameras. This enables an extendable readout of large tracking planes with commercial devices that reside almost entirely outside of the active medium. Following further development in intermediate scale demonstrators, this technique may represent a novel and enlargeable method for topological event imaging in 0
νββ
.
Abstract
NEXT-100 is currently being constructed at the Laboratorio
Subterráneo de Canfranc in the Spanish Pyrenees and will search
for neutrinoless double beta decay using a high-pressure gaseous
...time projection chamber (TPC) with 100 kg of xenon. Charge
amplification is carried out via electroluminescence (EL) which is
the process of accelerating electrons in a high electric field
region causing secondary scintillation of the medium proportional to
the initial charge. The NEXT-100 EL and cathode regions are made
from tensioned hexagonal meshes of 1 m diameter. This paper
describes the design, characterization, and installation of these
parts for NEXT-100. Simulations of the electric field are performed
to model the drift and amplification of ionization electrons
produced in the detector under various EL region alignments and
rotations. Measurements of the electrostatic breakdown voltage in
air characterize performance under high voltage conditions and
identify breakdown points. The electrostatic deflection of the mesh
is quantified and fit to a first-principles mechanical model.
Measurements were performed with both a standalone test EL region
and with the NEXT-100 EL region before its installation in the
detector. Finally, we describe the parts as installed in NEXT-100,
following their deployment in Summer 2023.
Noble element time projection chambers are a leading technology for rare event detection in physics, such as for dark matter and neutrinoless double beta decay searches. Time projection chambers ...typically assign event position in the drift direction using the relative timing of prompt scintillation and delayed charge collection signals, allowing for reconstruction of an absolute position in the drift direction. In this paper, alternate methods for assigning event drift distance via quantification of electron diffusion in a pure high pressure xenon gas time projection chamber are explored. Data from the NEXT-White detector demonstrate the ability to achieve good position assignment accuracy for both high- and low-energy events. Using point-like energy deposits from
83
m
Kr calibration electron captures (
E
∼
45
keV), the position of origin of low-energy events is determined to 2 cm precision with bias
<
1
mm. A convolutional neural network approach is then used to quantify diffusion for longer tracks (
E
≥
1.5
MeV), from radiogenic electrons, yielding a precision of 3 cm on the event barycenter. The precision achieved with these methods indicates the feasibility energy calibrations of better than 1% FWHM at Q
β
β
in pure xenon, as well as the potential for event fiducialization in large future detectors using an alternate method that does not rely on primary scintillation.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
We present a tunable metal ion beam that deliverscontrollable ion currents in the picoamp range for testing ofdry-phase ion sensors. Ion beams are formed by sequential atomicevaporation and single or ...multiple electron impact ionization,followed by acceleration into a sensing region. Controllability ofthe ionic charge state is achieved through tuning of electrodepotentials that influence the retention time in the ionizationregion. Barium, lead, and cadmium samples have been used to test thesystem, with ion currents identified and quantified using aquadrupole mass analyzer. Realization of a clean Ba2+ ion beam within a bench-top system represents an important technicaladvance toward the development and characterization of bariumtagging systems for neutrinoless double beta decay searches in xenongas. This system also provides a testbed for investigation of novelion sensing methodologies for environmental assay applications, withdication beams of Pb2+ and Cd2+ also demonstrated for thispurpose.
Abstract
We present a tunable metal ion beam that delivers
controllable ion currents in the picoamp range for testing of
dry-phase ion sensors. Ion beams are formed by sequential atomic
evaporation ...and single or multiple electron impact ionization,
followed by acceleration into a sensing region. Controllability of
the ionic charge state is achieved through tuning of electrode
potentials that influence the retention time in the ionization
region. Barium, lead, and cadmium samples have been used to test the
system, with ion currents identified and quantified using a
quadrupole mass analyzer. Realization of a clean Ba
2+
ion beam within a bench-top system represents an important technical
advance toward the development and characterization of barium
tagging systems for neutrinoless double beta decay searches in xenon
gas. This system also provides a testbed for investigation of novel
ion sensing methodologies for environmental assay applications, with
dication beams of Pb
2+
and Cd
2+
also demonstrated for this
purpose.
Extrauterine growth restriction affects most premature newborns. Early and higher parenteral protein intake seems to improve postnatal growth and associated comorbidities. We evaluate the impact of a ...new parenteral nutrition protocol based on early amino acid administration on postnatal growth in premature infants with a birth weight < 1,500 grams.
A case-control study in 58 premature newborns with a birth weight < 1,500 grams. In the case group we included 29 preterm neonates who received at least 1.5 g/kg/day parenteral amino acid during the first 24 hours after birth, reaching a maximum dose of 3.5 g/kg/day on the 3(rd)-4(th) day after birth. The control group was formed by 29 preterm neonates for whom protein support began on the 2(nd-)3(rd) day after birth with a dose of 1g/kg/day with lower daily increases than the case group. Growth rates and complications were followed until 28 days of life or discharge from NICU.
There were no differences between groups in baseline characteristics. Premature newborns who received higher and earlier doses of proteins had a greater weight gain than the control group, and this difference was statistically significant (423 ± 138 g vs. 315 ± 142 g; P=.005). In addition, they had a higher daily weight gain rate (19.4 ± 3.3 vs. 16.5 ± 4.8; P=.010) and they regained birth weight earlier (11.5 ± 3.3 days vs. 14.5 ± 4.5 days; P=.045). A higher incidence of complications was not observed.
Early and higher amino acid administration improves growth rate in premature neonates with no apparent increase in risks for the patient.
Abstract
Background
Hypertrophic cardiomyopathy (HCM) is the most common inherited cardiac disorder, with a prevalence between 1/250-500 individuals. The yield of genetic testing for this condition ...stands at 40%. The most prevalent genes are MYBPC3 and MYH7, with small contributions of other genes, such as TNNT2, TNNI3, TPM1, MYL2 or FHOD3. At our center, we have identified a recurrent variant in TNNT2, p.Asn271Ile, associated with HCM. Most probands came from the northwest of Spain (Galicia), which suggested that they may share a common origin.
Purpose
We aimed to determine whether carriers of the p.Asn271Ile variant in TNNT2 share a common haplotype, in order to estimate the age of the mutation and describe the associated phenotype.
Methods
We analyzed probands who had TNNT2 sequenced by NGS at our center. Enrichment of the variant was observed in the HCM cohort. Eight highly polymorphic microsatellite markers flanking the variant in 18 Galician HCM probands were also analyzed, compromising a region of approximately 7,300 kb. Custom PCR assays were designed, and fragment length analysis was performed by capillary electrophoresis.
Results
TNNT2 p.Asn271Ile was identified in 49/28,802 probands (0.17%). The variant was significantly enriched in HCM probands (47/11,870; 0.39%) compared to internal non-HCM controls (2/14,804; 0.02%), with an OR=29.3 (IC95%=7.1-120.7). The analysis revealed that the 18 HCM Galician probands shared a common haplotype of 500 kb, estimating that p.Asn271Ile has arisen approximately 26.5 generations ago (650 years).
Regarding genotype-phenotype correlation, our data (more than 180 carriers from 64 families) shows a relatively benign behavior, with an advance mean age at diagnosis (49.8 (±17.7), non-severe left ventricular hypertrophy 15.3 (±5.3), and a lower rate of major events among carriers of p.Asn271Ile in TNNT2, compared to both other genetic variants in TNNT2 and the main genetic cause of HCM (i.e., null variants in MYBPC3) (p=0.0001 for both comparisons). The prevalence of left ventricular systolic dysfunction and left ventricular tract obstruction was also smaller than that described for other sarcomeric genes (3.54% and 12%, respectively).
Conclusions
A founder effect of the pathogenic variant p.Asn271Ile has been demonstrated, with the variant arising approximately 650 years ago. The clinical behavior in carriers of this cohort showed to be relatively benign compared to the behavior of other genetic variants in this gene and null variants in MYBPC3.
The NEXT-White detector, a high-pressure gaseous xenon time projection chamber, demonstrated the excellence of this technology for future neutrinoless double beta decay searches using photomultiplier ...tubes (PMTs) to measure energy and silicon photomultipliers (SiPMs) to extract topology information. This analysis uses \(^{83m}\text{Kr}\) data from the NEXT-White detector to measure and understand the energy resolution that can be obtained with the SiPMs, rather than with PMTs. The energy resolution obtained of (10.9 \(\pm\) 0.6) \(\%\), full-width half-maximum, is slightly larger than predicted based on the photon statistics resulting from very low light detection coverage of the SiPM plane in the NEXT-White detector. The difference in the predicted and measured resolution is attributed to poor corrections, which are expected to be improved with larger statistics. Furthermore, the noise of the SiPMs is shown to not be a dominant factor in the energy resolution and may be negligible when noise subtraction is applied appropriately, for high-energy events or larger SiPM coverage detectors. These results, which are extrapolated to estimate the response of large coverage SiPM planes, are promising for the development of future, SiPM-only, readout planes that can offer imaging and achieve similar energy resolution to that previously demonstrated with PMTs.
