Fission dynamics of hot nuclei have been investigated using the two-dimensional Langevin equation. Including particle evaporation in the continuous limit, prescission multiplicities of neutrons, protons, and a particles have been calculated. Both the calculated number of prescission neutrons and the average total kinetic energy of fission fragments are consistent with experimental values when one-body dissipation is assumed. Unusually strong hydrodynamical two-body viscosity also reproduces the experimental neutron multiplicity, but it significantly underestimates the average kinetic energy. PACS numbers: 25.70.Jj, 25.85.Ge Collective motions of highly excited nuclei have been one of the interesting topics in nuclear physics in the last several years. Fissioning motion is a typical one and provides a good field to study nuclear collective dynamics in high excitation, i.e., fluctuation, dissipation, etc. One viewpoint is to consider collective degrees of freedom as Brownian particles and nucleonic ones as the heat bath. Thus, a primary interest is how strong friction is exerted on collective motions. Experimental evidence of fission as a slow and highly dissipative process has come from prescission multiplicities of neutrons [1], charged particles [2], and / rays [3]. In particular, neutrons are expected to work as a clock to measure fission time scale, because of their short life. Hinde, Hilscher, and Rossner [1] observed a prescission neutron multiplicity much larger than the value obtained with a simple statistical model. To analyze the prescission neutron data, they had to introduce a long delay time (~5xlO -20 s) during which fission cannot occur. From the observation of prescission 7 rays, Thoennessen et al. [3] also found a hindrance of fission consistent with neutron data. The delay time has been interpreted as a transient time during which the fissioning degree of freedom attains ''thermal equilibrium" inside the potential pocket, more precisely, quasistationary distribution in the phase space [4]. It depends on the strength of the friction force which is interpreted as the average effect of the interaction of the slow collective motion with already thermalized nucleons. Therefore, the friction constant of nuclear matter can be deduced by analyzing the fission time scale using the Fokker-Planck or Langevin equation.The kinetic energy distribution of fission fragments is another important observable related to fission dynamics; it is related to the descent from saddle to scission. Recently, realistic calculations were made for these two physical quantities using the two-dimensional Langevin equation with both one-body friction and hydrodynamical two-body viscosity [5]. The transient time obtained using the usual hydrodynamical viscosity [6] was 10 times shorter than that extracted from experiment. A stronger viscosity leads to a longer transient time but to a too small average kinetic energy of fission fragments when compared with Viola systematics [7]. On the other hand, the one-body friction gave an ...
Background A large number of patients suffer recurrence after curative resection, and mortality from colon cancer remains high. The role of systemic inflammatory response, as reflected by neutrophil-to-lymphocyte ratio (NLR), in cancer recurrence and death has been increasingly recognized. This study aimed to analyze long-term oncologic outcomes of Stage II-III colon cancer to examine the prognostic value of NLR using a propensity score analysis. Methods A total of 375 patients with colon cancer underwent radical surgery between 2000 and 2014 at Tokyo Medical University Hospital. Long-term oncologic outcomes of these patients were evaluated according to NLR values. A cut-off NLR of 3.0 was used based on receiver operating characteristic curve analysis. Primary outcomes were overall survival (OS) and relapse-free survival (RFS). An analysis of outcomes according to tumor sidedness was also performed. Results Patients with lower NLR values (“lower NLR group”) were more likely to have lymph node metastasis compared to those with higher NLR values (“higher NLR group”) before case matching. After case matching, clinical outcomes were similar between the two groups. There were no significant differences in 5-year OS and 5-year RFS rates between the two groups before case matching based on propensity scores. After case matching, 5-year OS rates were 94.5% in the lower NLR group (n = 135) and 87.0% in the higher NLR group (n = 135), showing a significant difference (p = 0.042). Five-year RFS rates were 87.8% in the lower NLR group and 77.9% in the higher NLR group, also showing a significant difference (p = 0.032). Among patients with left-sided colon cancer in the matched cohort, 5-year OS and 5-year RFS rates were 95.2 and 87.3% in the lower NLR group (n = 88), respectively, and 86.4 and 79.2% in the higher NLR group (n = 71), respectively, showing significant differences (p = 0.014 and p = 0.047, respectively). Conclusions The NLR is an important prognostic factor for advanced colon cancer, especially for left-sided colon cancer.
The fusion-fission process in heavy systems is analyzed by the Smoluchowski equation with the finite-range droplet model potential of no pocket and the temperature-dependent shell correction energy which generates the pocket around the spherical shape. The evaporation residue cross sections of superheavy elements have been shown to have an optimum value at a certain initial temperature, due to the balance between the diffusibility for fusion at high temperature and the restoration of the shell correction energy against fission at low temperature. ͓S0556-2813͑97͒50303-7͔
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