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Multiple Coulomb scattering of muons in lithium hydride
Get PDFMultiple Coulomb scattering (MCS) is a well-known phenomenon occurring when charged particles traverse materials. Measurements of muons traversing low Z materials made in the MuScat experiment showed that theoretical models and simulation codes, such as GEANT4 (v7.0), over-estimated the scattering. The Muon Ionization Cooling Experiment (MICE) measured the cooling of a muon beam traversing a liquid hydrogen or lithium hydride (LiH) energy absorber as part of a programme to develop muon accelerator facilities, such as a neutrino factory or a muon collider. The energy loss and MCS that occur in the absorber material are competing effects that alter the performance of the cooling channel. Therefore measurements of MCS are required in order to validate the simulations used to predict the cooling performance in future accelerator facilities. We report measurements made in the MICE apparatus of MCS using a LiH absorber and muons within the momentum range 160 to 245 MeV=c. The measured RMS scattering width is about 9% smaller than that predicted by the approximate formula proposed by the Particle Data Group, but within the latter's stated uncertainty. Data at 172, 200 and 240 MeV=c are compared to the GEANT4 (v9.6) default scattering model. These measurements show agreement with this more recent GEANT4 (v9.6) version over the range of incident muon momenta
Enhanced catalytic activity of phosphorus-modified SSZ-13 zeolite in the ethylene-to-propylene reaction by controlling acidity and intracrystalline diffusivity
No full textA highly selective means of producing propylene via the ethylene-to-propylene (ETP) reaction is required to manage the supply-demand balance of light olefins. To improve the catalytic activity of the ETP reaction, a phosphorus-modified SSZ-13 zeolite (P-SSZ-13) was prepared by introducing phosphorus to the SSZ-13 zeolite via a simple impregnation method. The P-SSZ-13 catalyst exhibited increased propylene selectivity and yield compared to the pristine catalyst. According to solid-state NMR spectroscopy and STEM-EDS observation, the phosphorus species were mainly located on the outer part of the crystal as a form of polyphosphate. To reveal the effect of the phosphorus loading on the enhancement of ETP reactivity, a series of surface-modified SSZ-13 catalysts were prepared and investigated. It was found that the polyphosphate species in the P-SSZ-13 catalyst not only weakened the acidity of the zeolite by bonding with the framework aluminum species but also reduced the diffusion out of the relatively large-sized hydrocarbon species by partially blocking the pore mouths. The change in the diffusivity of the hydrocarbons over the SSZ-13 catalysts also affected the ETP reactivity. The relationship between the amount of phosphorus and the ETP reactivity of the P-SSZ-13 catalysts could also be clearly demonstrated in terms of the change in both acidity and intracrystalline diffusivity. Moreover, 13C MAS NMR measurement with isotopic switch experiment confirmed the alkyl naphthalene-based hydrocarbon pool mechanism over the P-SSZ-13 for the ETP reaction
TET family proteins are dispensable for the structure and physiological function of dopamine neurons in health and Parkinson???s disease
No full textDNA undergoes demethylation via the oxidation of 5-methylcytosine (5mC), which is mediated by the Ten Eleven Translocation (TET) family of proteins. Notably, 5hmC is highly in the brain than in other tissues and is dynamically regulated according to development, aging, and brain diseases. In addition, accumulating evidence has recently revealed that 5-hmC and TETs play a significant role in synaptic functions, anxiety, addiction, and cognition in several brain regions. Furthermore, TET enzymes have turned out to be essential for diverse types of neurons in health and brain disorders. In this study, by generating triple knockout (TKO) mice of TET family proteins (TET1, 2, and 3) selectively in dopamine (DA) neurons, we investigated the roles of TET proteins in the structure and the function of DA neurons, which are pivotal for voluntary movement, reward-related behaviors, and motivation. We revealed that DA neuron-specific TET1, 2, 3 TKO does not alter cellular structure and survival of DA neurons. Furthermore, DA neurons from substantia nigra pars compacta (SNc) show that intrinsic properties and synaptic transmission of DA neurons are unchanged by disruption of TET family proteins. Thus, unexpectedly, cell type-specific KO of all three TET proteins did not lead to critical alterations of neuronal structure and function in DA neurons. Moreover, we revisited the pathophysiological importance of TET enzymes in Parkinson???s disease (PD) by utilizing both pharmacological and genetic mouse models of PD. Against our expectation, however, we found that PD pathology induced by two types of PD models is unaffected by disruption of TET family proteins, which suggests that the role of TET family proteins in the pathophysiology of PD can be insignificant. Thus, contrary to the previous reports, TET family enzymes may be dispensable for the structure and function of specific neurons in health and disease
Monitoring the effect of cellulose microfibers on internal curing of cement composites using linear and nonlinear resonance techniques
No full textPLC??1 in dopamine neurons critically regulates striatal dopamine release via VMAT2 and synapsin III
No full textDopamine neurons are essential for voluntary movement, reward learning,
and motivation, whose dysfunction is closely related to various psychological
and neurodegenerative diseases. Therefore, understanding the detailed
signaling mechanisms functionally modulating dopamine neurons is
crucial for the development of better therapeutic strategies against dopamine-
related disorders. In this study, we investigate the physiological role of
phospholipase C??1 (PLC??1), one of the key effector enzymes in intracellular
signaling, on regulating dopaminergic function in vivo. We found that cell
type-specific deletion of PLC??1 did not adversely affect morphology and
structure of midbrain dopamine neurons but did facilitate dopamine release
from dopaminergic axon terminals in the striatum. Elevated dopamine
release was accompanied by increased co-localization of vesicular monoamine
transporter 2 (VMAT2) at dopaminergic axons. Notably, dopamine
neuron-specific knockout of PLC??1 also led to the heightened expression
and co-localization of synapsin III that controls the trafficking of synaptic
vesicles. Our findings suggest that PLC??1 in dopamine neurons could critically
modulate dopamine release at axon terminals by directly or indirectly
interacting with synaptic machinery including VMAT2 and synapsin III
