The differential cross sections of the Σ^{-}p→Λn reaction were measured accurately for the Σ^{-} momentum (p_{Σ}) ranging from 470 to 650 MeV/c at the J-PARC Hadron Experimental Facility. Precise ...angular information about the Σ^{-}p→Λn reaction was obtained for the first time by detecting approximately 100 reaction events at each angular step of Δcosθ=0.1. The obtained differential cross sections show a slightly forward-peaking structure in the measured momentum regions. The cross sections integrated for -0.7≤cosθ≤1.0 were obtained as 22.5±0.68 statistical error(stat.) ±0.65 systematic error(syst.) mb and 15.8±0.83(stat)±0.52(syst) mb for 470<p_{Σ}(MeV/c)<550 and 550<p_{Σ}(MeV/c)<650, respectively. These results show a drastic improvement compared with past measurements of the hyperon-proton scattering experiments. They will play essential roles in updating the theoretical models of the baryon-baryon interactions.
The mechanisms by which the diffusion rate in the plasma membrane (PM) is regulated remain unresolved, despite their importance in spatially regulating the reaction rates in the PM. Proposed models ...include entrapment in nanoscale noncontiguous domains found in PtK2 cells, slow diffusion due to crowding, and actin-induced compartmentalization. Here, by applying single-particle tracking at high time resolutions, mainly to the PtK2-cell PM, we found confined diffusion plus hop movements (termed "hop diffusion") for both a nonraft phospholipid and a transmembrane protein, transferrin receptor, and equal compartment sizes for these two molecules in all five of the cell lines used here (actual sizes were cell dependent), even after treatment with actin-modulating drugs. The cross-section size and the cytoplasmic domain size both affected the hop frequency. Electron tomography identified the actin-based membrane skeleton (MSK) located within 8.8 nm from the PM cytoplasmic surface of PtK2 cells and demonstrated that the MSK mesh size was the same as the compartment size for PM molecular diffusion. The extracellular matrix and extracellular domains of membrane proteins were not involved in hop diffusion. These results support a model of anchored TM-protein pickets lining actin-based MSK as a major mechanism for regulating diffusion.
An
n
n
Λ
, which consists of two neutrons and a Lambda hyperon, is a multi-baryon system with no charge. Studying the
n
n
Λ
state would provide information about the
Λ
n
interaction which has not ...been directly measured by a scattering experiment. The experiment (E12-17-003) was performed in order to search for the
n
n
Λ
state at Jefferson Lab. The
n
n
Λ
is expected to be produced by the
(
e
,
e
′
K
+
)
reaction, which has sensitivity to both bound and resonance states if the natural width of the
n
n
Λ
is narrow enough to be observed as a peak. The experiment used gas targets of hydrogen and tritium for mass calibration and the
n
n
Λ
production, respectively. The mass calibration with
H
(
e
,
e
′
K
+
)
Λ
/
Σ
0
reactions gave the mass resolution of the
Λ
and
Σ
0
each 3.5
MeV
/
c
2
FWHM, for the elementary reaction. A spectrum of
3
H
(
e
,
e
′
K
+
)
X
was obtained, and a simple model with a
Λ
n
final state interaction was applied to reproduce the spectrum.
Abstract
We performed a novel Σ+p scattering experiment at the J-PARC Hadron Experimental Facility. Approximately 2400 Σ+p elastic scattering events were identified from 4.9 × 107 tagged Σ+ particles ...in the Σ+ momentum range 0.44–0.80 GeV/c. The differential cross sections of the Σ+p elastic scattering were derived with much better precision than in previous experiments. The obtained differential cross sections were approximately 2 mb/sr or less, which were not as large as those predicted by the fss2 and FSS models based on the quark cluster model in the short-range region. By performing phase-shift analyses for the obtained differential cross sections, we experimentally derived the phase shifts of the 3S1 and 1P1 channels for the first time. The phase shift of the 3S1 channel, where a large repulsive core was predicted owing to the Pauli effect between quarks, was evaluated as $20^\circ \lt |\delta _{^3S_1}|\lt 35^\circ$. If the sign of $\delta _{^3S_1}$ is assumed to be negative, the interaction in this channel is moderately repulsive, as the Nijmegen extended-sort-core models predicted.
Chemoradiation followed by surgery is the preferred treatment of localized gastroesophageal cancer (GEC). Surgery causes considerable life-altering consequences and achievement of clinical complete ...response (clinCR; defined as postchemoradiation but presurgery endoscopic biopsy negative for cancer and positron emission tomographic (PET) scan showing physiologic uptake) is an enticement to avoid/delay surgery. We examined the association between clinCR and pathologic complete response (pathCR).
Two hundred eighty-four patients with GEC underwent chemoradiation and esophagectomy. The chi-square test, Fisher exact test, t-test, Kaplan–Meier method, and log-rank test were used.
Of 284 patients, 218 (77%) achieved clinCR. However, only 67 (31%) of the 218 achieved pathCR. The sensitivity of clinCR for pathCR was 97.1% (67/69), but the specificity was low (29.8%; 64/215). Of the 66 patients who had less than a clinCR, only 2 (3%) had a pathCR. Thus, the rate of pathCR was significantly different in patients with clinCR than in those with less than a clinCR (P < 0.001).
clinCR is not highly associated with pathCR; the specificity of clinCR for pathCR is too low to be used for clinical decision making on delaying/avoiding surgery. Surgery-eligible GEC patients should be encouraged to undergo surgery following chemoradiation despite achieving a clinCR.
Glioblastomas (GBMs) are resistant to current therapy protocols and identification of molecules that target these tumors is crucial. Interaction of secreted heat-shock protein 70 ...(Hsp70)-Hsp90-organizing protein (HOP) with cellular prion protein (PrP(C)) triggers a large number of trophic effects in the nervous system. We found that both PrP(C) and HOP are highly expressed in human GBM samples relative to non-tumoral tissue or astrocytoma grades I-III. High levels of PrP(C) and HOP were associated with greater GBM proliferation and lower patient survival. HOP-PrP(C) binding increased GBM proliferation in vitro via phosphatidylinositide 3-kinase and extracellular-signal-regulated kinase pathways, and a HOP peptide mimicking the PrP(C) binding site (HOP230-245) abrogates this effect. PrP(C) knockdown impaired tumor growth and increased survival of mice with tumors. In mice, intratumor delivery of HOP230-245 peptide impaired proliferation and promoted apoptosis of GBM cells. In addition, treatment with HOP230-245 peptide inhibited tumor growth, maintained cognitive performance and improved survival. Thus, together, the present results indicate that interfering with PrP(C)-HOP engagement is a promising approach for GBM therapy.
Coastal sediment redeposition after resuspension events may change the sediment capacity to sequester pollutants after the formation of new sediment-water interfaces. To test this hypothesis, ...radiotracer experiments were performed to evaluate zinc (
65
Zn) and cadmium (
109
Cd) removal kinetics by redeposited mangrove sediments. After 24-h experiments, average inventories within redeposited sediments were close to those from control sediments (~ 20% lower in redeposited sediments), while average decreases of 41% (
109
Cd) and 27% (
65
Zn) in the half-removal times (
t
1/2
) from overlying water were promoted by redeposited sediments in comparison with control sediments. High variability in metal removal rates, however, implied in no statistically significant differences between
t
1/2
values, suggesting a low influence of sediment redeposition on the metal removal capacity of mangrove sediments. More limited depth diffusion of metals was observed within redeposited sediments, always within the uppermost centimeter. Possible benefits to water quality by a slightly faster metal diffusion into redeposited sediments may be less effective due to this trend since the metal retention very close to the sediment top can facilitate new remobilization to the overlying water.
An experiment to measure an invariant mass of <inline-formula> <tex-math notation="LaTeX">\phi </tex-math></inline-formula> mesons in nuclear medium is planned as the J-PARC E16 experiment. A trigger ...merging module (TRG-MRG) has been developed to detect leading-edges from 256 channels of discriminator-output signals and transmit those serialized hit data to trigger decision module with four optical links. The result of the test shows enough performance of the TRG-MRG as 1-ns time-to-digital converter (TDC) and data multiplexer with four 6.25 Gb/s transceivers.
•We carry out impact experiments using granular targets.•We observed the pattern of impact-induced ejecta using a high-speed camera.•Mesh pattern, loosely woven with spaces like a net, was ...observed.•The features of the mesh pattern are similar to some rays on the Moon.•Numerical simulation shows that inelastic mutual collisions lead to clear pattern.
We performed impact experiments with granular targets to reveal the formation process of crater “rays”, the non-uniform ejecta distributions around some fresh craters on the Moon and planets. We found mesh patterns, loosely woven with spaces like a net, as ejecta. A characteristic length of spaces between meshes was evaluated, and an angle, defined as the ratio of the characteristic length to the distance from the ejection point, was obtained as ∼a few degrees. These features are similar to the results of the analyses of the ray patterns around two lunar craters, Glushko and Kepler. Numerical simulations of granular material showed that clear mesh pattern appeared at lower coefficients of restitution between particles but was less clear at larger one, suggesting that the inelastic collisions between particles cause the clear mesh-pattern formation of impact ejecta.
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