Silicon photomultipliers (SiPMs) are now replacing photomultiplier tubes where low voltage operations, compactness, and cost per channel are important. However, optical crosstalk (OCT) is still one ...of the major disadvantages of SiPMs since it increases accidental triggers and degrades the accuracy of photon counting. Previously, we reported that OCTs can be suppressed by either thicker or no protection resin coating. Although no resin coating heavily suppresses OCTs, we still observe some OCTs at a few % levels. In this study, we have investigated the properties of OCTs and delayed OCTs for several types of SiPMs with different device sizes, cell sizes, and resin coating thickness. We observe that delayed OCTs have very similar properties compared with OCTs with no resin coating. Furthermore, we find that the sizable amount of delayed OCTs is overlapping with the original pulse and may be treated as OCTs when the delay is less than 8 ns in our analysis. Since the properties and rate of overlaps of delayed OCTs match those of OCTs with no resin coating, we conclude that the remaining OCTs for SiPMs with no coating can be fully explained by overlaps of delayed OCTs.
We investigate strong-coupling effects in a three-component atomic Fermi gas. It is a promising candidate for simulating quantum chromodynamics, and furthermore, the emergence of various phenomena ...such as color superfluidity and Efimov effect is anticipated in this system. In this paper, we study the effects of two-body and three-body correlations by means of the many-body
T
-matrix approximation as well as the Skorniakov–Ter-Martirosian equation with medium corrections. We investigate the effects of finite temperature and chemical potential on the trimer binding energy at the superfluid critical point of the unitarity limit.
Strong magnetic fields, synchrotron emission, and Compton scattering are omnipresent in compact celestial X-ray sources. Emissions in the X-ray energy band are consequently expected to be linearly ...polarized. X-ray polarimetry provides a unique diagnostic to study the location and fundamental mechanisms behind emission processes. The polarization of emissions from a bright celestial X-ray source, the Crab, is reported here for the first time in the hard X-ray band (~20-160 keV). The Crab is a complex system consisting of a central pulsar, a diffuse pulsar wind nebula, as well as structures in the inner nebula including a jet and torus. Measurements are made by a purpose-built and calibrated polarimeter, PoGO+. The polarization vector is found to be aligned with the spin axis of the pulsar for a polarization fraction, PF = (20.9 ± 5.0)%. This is higher than that of the optical diffuse nebula, implying a more compact emission site, though not as compact as, e.g., the synchrotron knot. Contrary to measurements at higher energies, no significant temporal evolution of phase-integrated polarisation parameters is observed. The polarization parameters for the pulsar itself are measured for the first time in the X-ray energy band and are consistent with observations at optical wavelengths.
ABSTRACT A study of the interstellar medium (ISM) and cosmic rays (CRs) using Fermi Large Area Telescope (LAT) data, in a region encompassing the nearby molecular clouds MBM 53, 54, and 55 and a ...far-infrared loop-like structure in Pegasus, is reported. By comparing the Planck dust thermal emission model with Fermi-LAT γ-ray data, it was found that neither the dust radiance (R) nor the dust opacity at 353 GHz (τ353) was proportional to the total gas column density N(Htot) primarily because N(Htot)/R and N(Htot)/τ353 depend on the dust temperature (Td). The N(Htot) distribution was evaluated using γ-ray data by assuming the regions of high Td to be dominated by optically thin atomic hydrogen ( ) and by employing an empirical linear relation of N(Htot)/R to Td. It was determined that the mass of the gas not traced by the 21 cm or 2.6 mm surveys is ∼25% of the mass of in the optically thin case and is larger than the mass of the molecular gas traced by carbon monoxide by a factor of up to 5. The measured γ-ray emissivity spectrum is consistent with a model based on CR spectra measured at the Earth and a nuclear enhancement factor of ≤1.5. It is, however, lower than local emissivities reported by previous Fermi-LAT studies employing different analysis methods and assumptions on ISM properties by 15%-20% in energies below a few GeV, even if we take account of the statistical and systematic uncertainties. The origin of the discrepancy is also discussed.
An accurate estimate of the interstellar gas density distribution is crucial to understanding the interstellar medium (ISM) and Galactic cosmic rays (CRs). To comprehend the ISM and CRs in a local ...environment, a study of the diffuse γ-ray emission in a midlatitude region of the third quadrant was performed. The γ-ray data in the 0.1-25.6 GeV energy range of the Fermi Large Area Telescope (LAT) and other interstellar gas tracers such as the HI4PI survey data and the Planck dust thermal emission model were used, and the northern and southern regions were analyzed separately. The variation of the dust emission with the total neutral gas column density was studied in high dust temperature areas, and the / ratio was calibrated using γ-ray data under the assumption of a uniform CR intensity in the studied regions. The measured integrated γ-ray emissivities above 100 MeV are and in the northern and southern regions, respectively, supporting the existence of a uniform CR intensity in the vicinity of the solar system. While most of the gas can be interpreted to be with a spin temperature of or higher, an area dominated by optically thick with was identified.
We present an analysis of the interstellar medium (ISM) toward the gamma -ray supernova remnant (SNR) W44. We used NANTEN2 super(12)CO(J = 2-1) and super(l2)CO(J = 1-0) data and Arecibo H I data in ...order to identify the molecular and atomic gas in the SNR. We confirmed that the molecular gas is located in the SNR shell with a primary peak toward the eastern edge of the shell. We newly identified high-excitation molecular gas along the eastern shell of the SNR in addition to the high-excitation broad gas previously observed inside the shell; the line intensity ratio between the super(12)CO(J = 2-1) and super(l2)CO(J = 1-0) transitions in these regions is greater than ~1.0, suggesting a kinetic temperature of 30 K or higher, which is most likely due to heating by shock interaction. By comparing the ISM with gamma -rays, we find that target protons of hadronic origin are dominated by molecular protons of average density around 200 cm super(-3), where the possible contribution of atomic protons is 10% or less. This average density is consistent with the recent discovery of the low-energy gamma -rays suppressed in 50 MeV-10 GeV as observed with AGILE and Fermi. The gamma -ray spectrum differs from place to place in the SNR, suggesting that the cosmic-ray (CR) proton spectrum significantly changes within the middle-aged SNR perhaps due to the energy-dependent escape of CR protons from the acceleration site. We finally derive a total CR proton energy of ~10 super(49) erg, consistent with the SN origin of the majority of the CRs in the Galaxy.
Background and Objective
Hypophosphatasia is a rare inherited skeletal disorder characterized by defective bone mineralization and deficiency of tissue non‐specific alkaline phosphatase (TNSALP) ...activity. The disease is caused by mutations in the liver/bone/kidney alkaline phosphatase gene (ALPL) encoding TNSALP. Early exfoliation of primary teeth owing to disturbed cementum formation, periodontal ligament weakness and alveolar bone resorption are major complications encountered in oral findings, and discovery of early loss of primary teeth in a dental examination often leads to early diagnosis of hypophosphatasia. Although there are no known fundamental treatments or effective dental approaches to prevent early exfoliation of primary teeth in affected patients, several possible treatments have recently been described, including gene therapy. Gene therapy has also been applied to TNSALP knockout mice (Alpl−/−), which phenocopy the infantile form of hypophosphatasia, and improved their systemic condition. In the present study, we investigated whether gene therapy improved the dental condition of Alpl−/− mice.
Material and Methods
Following sublethal irradiation (4 Gy) at the age of 2 d, Alpl−/− mice underwent gene therapy using bone marrow cells transduced with a lentiviral vector expressing a bone‐targeted form of TNSALP injected into the jugular vein (n = 3). Wild‐type (Alpl+/+), heterozygous mice (Alpl+/−) and Alpl−/− mice were analyzed at 9 d of age (n = 3 of each), while Alpl+/+ mice and treated or untreated Alpl−/− mice were analyzed at 1 mo of age (n = 3 of each), and Alpl+/− mice and Alpl−/− mice with gene therapy were analyzed at 3 mo of age (n = 3 of each). A single mandibular hemi‐section obtained at 1 mo of age was analyzed using a small animal computed tomography machine to assess alveolar bone formation. Other mandibular hemi‐sections obtained at 9 d, 1 mo and 3 mo of age were subjected to hematoxylin and eosin staining and immunohistochemical analysis of osteopontin, a marker of cementum.
Results
Immunohistochemical analysis of osteopontin, a marker of acellular cementum, revealed that Alpl−/− mice displayed impaired formation of cementum and alveolar bone, similar to the human dental phenotype. Cementum formation was clearly present in Alpl−/− mice that underwent gene therapy, but did not recover to the same level as that in wild‐type (Alpl+/+) mice. Micro‐computed tomography examination showed that gene therapy improved alveolar bone mineral density in Alpl−/− mice to a similar level to that in Alpl+/+ mice.
Conclusions
Our results suggest that gene therapy can improve the general condition of Alpl−/− mice, and induce significant alveolar bone formation and moderate improvement of cementum formation, which may contribute to inhibition of early spontaneous tooth exfoliation.
Abstract Background Recent advances in gastric cancer chemotherapy have made macroscopic complete resection possible in some patients with stage IV disease. Methods We retrospectively investigated ...the efficacy of multimodal therapy with combined docetaxel, cisplatin, and S-1 (DCS) and conversion gastrectomy in 57 patients with stage IV gastric cancer. Results Of the 57 patients, 15 patients were categorized into potentially resectable case, which is defined as patients with single incurable factor including the upper abdominal para-aortic lymph node metastasis (16a2b1 PAN metastasis) or fewer than three peripheral liver metastases. The other 42 were categorized as initially unresectable. All of patients underwent DCS therapy, and then 34 patients underwent conversion gastrectomy. The 3-year overall survival (OS) rate among the patients who underwent conversion gastrectomy was 50.1% with MST of 29.9 months. They had significantly longer OS than patients who underwent DCS therapy alone (p < 0.01). Univariate analysis among the patents with conversion gastrectomy identified 16a2b1PAN metastasis, peritoneal metastasis, potential resectable case, R0 resection as significant prognostic factors. A 3-year OS in potential resectable cases was 92.9%. Multivariate analysis identified potential resectability as the only independent prognostic factor contributing to OS (HR 0.133, 95%CI 0.024-0. 744, p = 0.021). In contrast, clinical response was selected as the only independent prognostic factor in the subgroup of initially unresectable cases (HR 0.354, 95%CI 0.151-0.783, p = 0.021). Conclusion Patients with potentially resectable disease had a remarkably good prognosis among stage IV gastric cancer patients, and might be ideal candidates for conversion gastrectomy following DCS therapy.
All camera designs for Small-Sized telescopes (SSTs) proposed for the Cherenkov Telescope Array (CTA) utilize silicon photomultipliers (SiPM) as their baseline photon sensor technology. The ...dual-mirror SST (SST-2M) has a smaller plate scale (i.e. image size) than the single-mirror SST, allowing it to employ 2,000 square SiPMs with pixel sizes of approximately 6 mm, close to the mainstream SiPM sizes.
In CTA, the night sky background level of typically ∼25 Mcounts/s/pixel (>100 Mcounts/s/pixel at maximum) places severe constraints on the trigger capability due to accidental coincidence on neighboring pixels. In order to suppress such events, it is necessary to reduce optical crosstalk, a mechanism whereby a single optical photon can produce multiple avalanches in the SiPM, while keeping good photon detection efficiency. These are, in general, contradicting requirements.
In this manuscript, we report on characterization of a variety of SiPM technologies for SST-2M cameras and compare results obtained at different participating institutions. We assess the harmonization of results and discuss the likely performance that will be achieved for the first production cameras.
•Scaling of SiPM parameters with known factors helps to find other unknown factors.•Lower breakdown SiPM yields better photon detection efficiencies at lower crosstalk.•The SiPM optical crosstalk can be reduced by thicker protection coating above 100 μm.•Lower breakdown SiPM yields better photon detection efficiencies at lower crosstalk.
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