Measurement of the total neutron scattering cross section ratios of noble gases of natural isotopic composition using a pulsed neutron beam

Precision measurements of slow neutron cross sections with atoms have several scientific applications. In particular the n-$^{4}$He s-wave scattering length is important to know both for helping to constrain the nuclear three-body interaction and for the proper interpretation of several ongoing slow neutron experiments searching for other types of neutron-atom interactions. We present new measurements of the ratios of the neutron differential scattering cross sections for natural isotopic-abundance mixtures of the noble gases He, Ar, Kr, and Xe to natural isotopic abundance Ne. These measurements were performed using a recently developed neutron scattering apparatus for gas samples located on a pulsed slow neutron beamline which was designed to search for possible exotic neutron-atom interactions and employs both neutron time of flight information and a position-sensitive neutron detector for scattering event reconstruction. We found agreement with the literature values of scattering cross sections inferred from Ar/Ne, Kr/Ne and Xe/Ne differential cross section ratios over the $q$ range of $1 - 7$ nm$^{-1}$. However for the case of He/Ne we find that the cross section inferred differs by 11.3% (7.6 $\sigma$) from previously-reported values inferred from neutron phase shift measurements, but is in reasonable agreement with values from other measurements. The very large discrepancy in the He/Ne ratio calls for a new precision measurement of the n-$^{4}$He scattering length using neutron interferometry

Recurrent Ascending Colon Cancer Manifesting as Inferior Vena cava Thrombus

We report an extremely rare case of recurrent ascending colon cancer manifesting as inferior vena cava (IVC) thrombus. A 77-year-old woman previously diagnosed with ascending colon cancer underwent right hemicolectomy with lymph node dissection. Though the tumor invaded the retroperitoneum and involved the right ovarian artery and vein, curative operation was performed. The patient took 5-FU p.o. Two and a half years later, tumor thrombus in the IVC extending into the right atrium was incidentally found and diagnosed as recurrence of colon cancer by biopsy. RF-induced hyperthermia using 5-FU and CDDP i.v. was immediately performed, but she died after 6 months because of multiple liver and pulmonary metastases. In treating colon cancers invading the retroperitoneum, it should be recalled that some cases recur as tumor thrombus in the IVC and that close follow-up is therefore necessary