Langevin dynamics of heavy quarks in a soft-hard factorized approach

By utilizing a soft-hard factorized model, which combines a thermal perturbative description of soft scatterings and a perturbative QCD-based calculation for hard collisions, we study the energy and temperature dependence of the heavy quark diffusion coefficients in Langevin dynamics. The adjustable parameters are fixed from the comprehensive model-data comparison. We find that a small value of the spatial diffusion coefficient at transition temperature is preferred by data $2\pi TD_{s}(T_{c}) \simeq 6$. With the parameter-optimized model, we are able to describe simultaneously the prompt $D^{0}$ $R_{\rm AA}$ and $v_{2}$ data at $p_{\rm T}\le8$ GeV in Pb--Pb collisions at $\sqrt{s_{\rm NN}}=2.76$ and $\sqrt{s_{\rm NN}}=5.02$ TeV. We also make predictions for non-prompt $D^{0}$ meson for future experimental tests down to the low momentum region.Comment: 13 pages, 10 figure

Methylenetetrahydrofolate reductase polymorphism and capecitabine-induced toxicity in patients with gastric cancer

Purpose: To evaluate the effect of methylenetetrahydrofolate reductase (MTHFR) polymorphism on toxicity in gastric cancer (GC) patients treated with capecitabine. Methods: One hundred and twenty-six GC patients were treated with capecitabine in the study. DNA from GC patients was genotyped for MTHFR A1298C using direct sequencing. Toxicity evaluations were graded. Clinical response was assessed. Results: In 87.3 % of the patients, capecitabine toxicity was observed. As for MTHFR A1298C polymorphism, 55.6 % patients who exhibited it were associated with reduced MTHFR activity. MTHFR A1298C was associated with capecitabine-related toxicity (p = 0.008); in addition, MTHFR A1298C was significantly associated with gastrointestinal toxicity (p = 0.026), but not with other types of toxicity. Conclusion: The findings suggest that MTHFR A1298C may be useful for predicting toxicity in GC patients receiving capecitabine treatment, especially gastrointestinal toxicity. Keywords: MTHFR, Polymorphism, Gastric cancer, Toxicit