Independent and cumulative production cross-sections for the (nat)Ti(p,x)(48)V, (43,44m,44g,46,47,48)Sc nuclear processes are reported here, for the energy region of 4-38MeV by using a stacked-foil ...activation technique. Measured data were critically compared with the earlier reported values, and also with the theoretical data from the TALYS and ALICE-IPPE codes. The measured (nat)Ti(p,x)(48)V reaction is important for charged particle beam monitoring purposes, whereas the (43,44,47)Sc radionuclide have various practical applications in nuclear medicine.
The Heavy Photon Search experiment (HPS) at the Thomas Jefferson National
Accelerator Facility searches for electro-produced dark photons. We report
results from the 2016 Engineering Run consisting ...of 10608/nb of data for both
the prompt and displaced vertex searches. A search for a prompt resonance in
the $e^+e^-$ invariant mass distribution between 39 and 179 MeV showed no
evidence of dark photons above the large QED background, limiting the coupling
of {\epsilon}^2 {\geq} 10^-5, in agreement with previous searches. The search
for displaced vertices showed no evidence of excess signal over background in
the masses between 60 and 150 MeV, but had insufficient luminosity to limit
canonical heavy photon production. This is the first displaced vertex search
result published by HPS. HPS has taken high-luminosity data runs in 2019 and
2021 that will explore new dark photon phase space.
A new electron scattering experiment (E12-21-003) to verify and understand the nature of hidden sector particles, with particular emphasis on the so-called X17 particle, has been approved at ...Jefferson Lab. The search for these particles is motivated by new hidden sector models introduced to account for a variety of experimental and observational puzzles: excess in \(e^+e^-\) pairs observed in multiple nuclear transitions, the 4.2\(\sigma\) disagreement between experiments and the standard model prediction for the muon anomalous magnetic moment, and the small-scale structure puzzle in cosmological simulations. The aforementioned X17 particle has been hypothesized to account for the excess in \(e^+e^-\) pairs observed from the \(^8\)Be M1, \(^4\)He M0, and, most recently, \(^{12}\)C E1 nuclear transitions to their ground states observed by the ATOMKI group. This experiment will use a high resolution electromagnetic calorimeter to search for or set new limits on the production rate of the X17 and other hidden sector particles in the \(3 - 60\) MeV mass range via their \(e^+e^-\) decay (or \(\gamma\gamma\) decay with limited tracking). In these models, the \(1 - 100\) MeV mass range is particularly well-motivated and the lower part of this range still remains unexplored. Our proposed direct detection experiment will use a magnetic-spectrometer-free setup (the PRad apparatus) to detect all three final state particles in the visible decay of a hidden sector particle for an effective control of the background and will cover the proposed mass range in a single setting. The use of the well-demonstrated PRad setup allows for an essentially ready-to-run and uniquely cost-effective search for hidden sector particles in the \(3 - 60\) MeV mass range with a sensitivity of 8.9\(\times\)10\(^{-8}\) - 5.8\(\times\)10\(^{-9}\) to \(\epsilon^2\), the square of the kinetic mixing interaction constant between hidden and visible sectors.
Independent and cumulative production cross-sections for the
natTi(p,
x)
48V,
43,44m,44g,46,47,48Sc nuclear processes are reported here, for the energy region of 4–38
MeV by using a stacked-foil ...activation technique. Measured data were critically compared with the earlier reported values, and also with the theoretical data from the TALYS and ALICE-IPPE codes. The measured
natTi(p,
x)
48V reaction is important for charged particle beam monitoring purposes, whereas the
43,44,47Sc radionuclide have various practical applications in nuclear medicine.
Comorbid depression and Alzheimer's disease (AD) is associated with poorer prognosis than either condition alone. Neuroinflammation has been implicated in the pathogenesis and progression of both ...depression and AD, but much of the existing research has been based on peripheral blood immune markers. Relatively little is known about the neuroinflammatory environment when these conditions occur simultaneously and using immune measures directly in the brain tissue. This pilot study aimed to examine brain inflammatory marker changes in AD cases comparing those with and without comorbid depression.
Post-mortem brain tissue from AD cases with depression (n = 23) and AD cases with no history of psychiatric illness (n = 25) were analyzed for a range of inflammatory markers, including markers of microglial function (Iba1, P2RY12, CD64 and CD68 measured by immunohistochemistry); endothelial inflammatory markers (ICAM-1 and VCAM-1 measured by ELISA); and cytokine levels (IFN-γ, IL-1β, IL-2, IL-4, IL-6, IL-8, IL-10, IL-12p70, IL-13, and TNF-α measured using Mesoscale Discovery Multiplex Assays).
Brains of AD cases with comorbid depression, compared with AD alone, had increased IL-4 in the superior frontal gyrus and increased TNFα & IL-12p70 in the insula. Levels of all other inflammatory markers including markers of microglial function and endothelial inflammation were similar between the two groups.
We found no consistent changes in cytokines between the two brain regions in individuals with comorbid depression in AD. Further work in larger cohorts is needed to understand brain region specificity of immune marker alterations and the relationship of these changes with pre-mortem clinical outcomes.
•It is unclear why some individuals with AD develop depression. Current treatments are ineffective for depression in AD.•We investigated whether neuroinflammation is involved in depression in AD using brain tissue from people with AD +/− depression.•We measured 10 different cytokines and two downstream markers of the effect of neuroinflammation on blood vessels in the brain.•We found no consistent differences between the two brain areas that we studied, suggesting neuroinflammation is not the cause of depression in AD.
In our quest to understand the nature of dark matter and discover its non-gravitational interactions with ordinary matter, we propose an experiment using a \pbo ~calorimeter to search for or set new ...limits on the production rate of i) hidden sector particles in the \(3 - 60\) MeV mass range via their \(e^+e^-\) decay (or \(\gamma\gamma\) decay with limited tracking), and ii) the hypothetical X17 particle, claimed in multiple recent experiments. The search for these particles is motivated by new hidden sector models and dark matter candidates introduced to account for a variety of experimental and observational puzzles: the small-scale structure puzzle in cosmological simulations, anomalies such as the 4.2\(\sigma\) disagreement between experiments and the standard model prediction for the muon anomalous magnetic moment, and the excess of \(e^+e^-\) pairs from the \(^8\)Be M1 and \(^4\)He nuclear transitions to their ground states observed by the ATOMKI group. In these models, the \(1 - 100\) MeV mass range is particularly well-motivated and the lower part of this range still remains unexplored. Our proposed direct detection experiment will use a magnetic-spectrometer-free setup (the PRad apparatus) to detect all three final state particles in the visible decay of a hidden sector particle allowing for an effective control of the background and will cover the proposed mass range in a single setting. The use of the well-demonstrated PRad setup allows for an essentially ready-to-run and uniquely cost-effective search for hidden sector particles in the \(3 - 60\) MeV mass range with a sensitivity of 8.9\(\times\)10\(^{-8}\) - 5.8\(\times\)10\(^{-9}\) to \(\epsilon^2\), the square of the kinetic mixing interaction constant between hidden and visible sectors. This updated proposal includes our response to the PAC49 comments.
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