Association Among Polyphenol Intake, Uric Acid, and Hyperuricemia: A CrossSectional Analysis in a Population at High Cardiovascular Risk

Dietary polyphenol intake has been associated with a decreased risk of hyperuricemia, but most of this knowledge comes from preclinical studies. The aim of the present study was to assess the association of the intake of different classes of polyphenols with serum uric acid and hyperuricemia. This cross- sectional analysis involved baseline data of 6332 participants. Food polyphenol con- tent was estimated by a validated semiquantitative food frequency questionnaire and from the Phenol-Explorer database. Multivariable-adjusted linear regression models with serum uric acid (milligrams per deciliter) as the outcome and polyphenol intake (quintiles) as the main independent variable were fitted. Cox regression models with constant follow-up time (t=1) were performed to estimate the prevalence ratios (PRs) of hyperuricemia (≥7 mg/dL in men and ≥6 mg/dL in women). An inverse association between the intake of the phenolic acid class (β coefficient, −0.17 mg/dL for quintile 5 versus quintile 1 [95% CI, −0.27 to −0.06]) and hydroxycinnamic acids (β coefficient, −0.19 [95% CI, −0.3 to −0.09]), alkylmethoxyphenols (β coefficient, −0.2 [95% CI, −0.31 to −0.1]), and methoxyphenols (β coefficient, −0.24 [95% CI, −0.34 to −0.13]) subclasses with serum uric acid levels and hyperuricemia (PR, 0.82 [95% CI, 0.71– 0.95]; PR, 0.82 [95% CI, 0.71– 0.95]; PR, 0.80 [95% CI, 0.70– 0.92]; and PR, 0.79 [95% CI, 0.69– 0.91]; respectively) was found. The intake of hydroxybenzoic acids was directly and significantly as- sociated with mean serum uric acid levels (β coefficient, 0.14 for quintile 5 versus quintile 1 [95% CI, 0.02– 0.26]) but not with hyperuricemia

Multiwavelength study of the galactic PeVatron candidate LHAASO J2108+5157

Context. Several new ultrahigh-energy (UHE) γ-ray sources have recently been discovered by the Large High Altitude Air Shower Observatory (LHAASO) collaboration. These represent a step forward in the search for the so-called Galactic PeVatrons, the enigmatic sources of the Galactic cosmic rays up to PeV energies. However, it has been shown that multi-TeV γ-ray emission does not necessarily prove the existence of a hadronic accelerator in the source; indeed this emission could also be explained as inverse Compton scattering from electrons in a radiation-dominated environment. A clear distinction between the two major emission mechanisms would only be made possible by taking into account multi-wavelength data and detailed morphology of the source. Aims. We aim to understand the nature of the unidentified source LHAASO J2108+5157, which is one of the few known UHE sources with no very high-energy (VHE) counterpart. Methods. We observed LHAASO J2108+5157 in the X-ray band with XMM-Newton in 2021 for a total of 3.8 hours and at TeV energies with the Large-Sized Telescope prototype (LST-1), yielding 49 hours of good-quality data. In addition, we analyzed 12 years of Fermi-LAT data, to better constrain emission of its high-energy (HE) counterpart 4FGL J2108.0+5155. We used naima and jetset software packages to examine the leptonic and hadronic scenario of the multi-wavelength emission of the source. Results. We found an excess (3.7σ) in the LST-1 data at energies E > 3 TeV. Further analysis of the whole LST-1 energy range, assuming a point-like source, resulted in a hint (2.2σ) of hard emission, which can be described with a single power law with a photon index of Σ = 1.6 ± 0.2 the range of 0.3 - 100 TeV. We did not find any significant extended emission that could be related to a supernova remnant (SNR) or pulsar wind nebula (PWN) in the XMM-Newton data, which puts strong constraints on possible synchrotron emission of relativistic electrons. We revealed a new potential hard source in Fermi-LAT data with a significance of 4σ and a photon index of Σ = 1.9 ± 0.2, which is not spatially correlated with LHAASO J2108+5157, but including it in the source model we were able to improve spectral representation of the HE counterpart 4FGL J2108.0+5155. Conclusions. The LST-1 and LHAASO observations can be explained as inverse Compton-dominated leptonic emission of relativistic electrons with a cutoff energy of 100-30+70 TeV. The low magnetic field in the source imposed by the X-ray upper limits on synchrotron emission is compatible with a hypothesis of a PWN or a TeV halo. Furthermore, the spectral properties of the HE counterpart are consistent with a Geminga-like pulsar, which would be able to power the VHE-UHE emission. Nevertheless, the lack of a pulsar in the neighborhood of the UHE source is a challenge to the PWN/TeV-halo scenario. The UHE γ rays can also be explained as π0 decay-dominated hadronic emission due to interaction of relativistic protons with one of the two known molecular clouds in the direction of the source. Indeed, the hard spectrum in the LST-1 band is compatible with protons escaping a shock around a middle-aged SNR because of their high low-energy cut-off, but the origin of the HE γ-ray emission remains an open question

Development of an advanced SiPM camera for the Large Size Telescope of the Cherenkov TelescopeArray Observatory

Silicon photomultipliers (SiPMs) have become the baseline choice for cameras of the small-sized telescopes (SSTs) of the Cherenkov Telescope Array (CTA). On the other hand, SiPMs are relatively new to the field and covering large surfaces and operating at high data rates still are challenges to outperform photomultipliers (PMTs). The higher sensitivity in the near infra-red and longer signals compared to PMTs result in higher night sky background rate for SiPMs. However, the robustness of the SiPMs represents a unique opportunity to ensure long-term operation with low maintenance and better duty cycle than PMTs. The proposed camera for large size telescopes will feature 0.05 degree pixels, low power and fast front-end electronics and a fully digital readout. In this work, we present the status of dedicated simulations and data analysis for the performance estimation. The design features and the different strategies identified, so far, to tackle the demanding requirements and the improved performance are described

Commissioning of the camera of the first Large Size Telescope of the Cherenkov Telescope Array

The first Large Size Telescope (LST-1) of the Cherenkov Telescope Array has been operational since October 2018 at La Palma, Spain. We report on the results obtained during the camera commissioning. The noise level of the readout is determined as a 0.2 p.e. level. The gain of PMTs are well equalized within 2% variation, using the calibration flash system. The eect of the night sky background on the signal readout noise as well as the PMT gain estimation are also well evaluated. Trigger thresholds are optimized for the lowest possible gamma-ray energy threshold and the trigger distribution synchronization has been achieved within 1 ns precision. Automatic rate control realizes the stable observation with 1.5% rate variation over 3 hours. The performance of the novel DAQ system demonstrates a less than 10% dead time for 15 kHz trigger rate even with sophisticated online data correction

Association Among Polyphenol Intake, Uric Acid, and Hyperuricemia: A Cross‐Sectional Analysis in a Population at High Cardiovascular Risk

Background Dietary polyphenol intake has been associated with a decreased risk of hyperuricemia, but most of this knowledge comes from preclinical studies. The aim of the present study was to assess the association of the intake of different classes of polyphenols with serum uric acid and hyperuricemia. Methods and Results This cross‐sectional analysis involved baseline data of 6332 participants. Food polyphenol content was estimated by a validated semiquantitative food frequency questionnaire and from the Phenol‐Explorer database. Multivariable‐adjusted linear regression models with serum uric acid (milligrams per deciliter) as the outcome and polyphenol intake (quintiles) as the main independent variable were fitted. Cox regression models with constant follow‐up time (t=1) were performed to estimate the prevalence ratios (PRs) of hyperuricemia (≥7 mg/dL in men and ≥6 mg/dL in women). An inverse association between the intake of the phenolic acid class (β coefficient, −0.17 mg/dL for quintile 5 versus quintile 1 [95% CI, −0.27 to −0.06]) and hydroxycinnamic acids (β coefficient, −0.19 [95% CI, −0.3 to −0.09]), alkylmethoxyphenols (β coefficient, −0.2 [95% CI, −0.31 to −0.1]), and methoxyphenols (β coefficient, −0.24 [95% CI, −0.34 to −0.13]) subclasses with serum uric acid levels and hyperuricemia (PR, 0.82 [95% CI, 0.71–0.95]; PR, 0.82 [95% CI, 0.71–0.95]; PR, 0.80 [95% CI, 0.70–0.92]; and PR, 0.79 [95% CI, 0.69–0.91]; respectively) was found. The intake of hydroxybenzoic acids was directly and significantly associated with mean serum uric acid levels (β coefficient, 0.14 for quintile 5 versus quintile 1 [95% CI, 0.02–0.26]) but not with hyperuricemia. Conclusions In individuals with metabolic syndrome, a higher intake of some polyphenol subclasses (hydroxycinnamic acids, alkylmethoxyphenol, and methoxyphenol) was inversely associated with serum uric acid levels and hyperuricemia. Nevertheless, our findings warrant further research