On Efficient Second Order Stabilized Semi-Implicit Schemes for the Cahn-Hilliard Phase-Field Equation

Efficient and energy stable high order time marching schemes are very important but not easy to construct for the study of nonlinear phase dynamics. In this paper, we propose and study two linearly stabilized second order semi-implicit schemes for the Cahn-Hilliard phase-field equation. One uses backward differentiation formula and the other uses Crank-Nicolson method to discretize linear terms. In both schemes, the nonlinear bulk forces are treated explicitly with two second-order stabilization terms. This treatment leads to linear elliptic systems with constant coefficients, for which lots of robust and efficient solvers are available. The discrete energy dissipation properties are proved for both schemes. Rigorous error analysis is carried out to show that, when the time step-size is small enough, second order accuracy in time is obtained with a prefactor controlled by a fixed power of $1/\varepsilon$, where $\varepsilon$ is the characteristic interface thickness. Numerical results are presented to verify the accuracy and efficiency of proposed schemes

Gene expression profiling of rat livers with Yin-deficiency-heat syndrome

AbstractObjectiveTo explore the nature of ”Yin internal heat caused by Yin-deficiency,” in terms of the theory of Traditional Chinese Medicine, by studying energy metabolism in rats with Yin-deficiency-heat syndrome and analyzing the gene expression profile of their livers.MethodsA Yin-deficiency-heat syndrome model was induced in rats using three Chinese medicinal herbs. Glycogen and triglycerides in blood plasma, and the enzyme activity of ATP in livers were measured colorimetrically. Triiodothyronine (T3), thyroxine (T4), and thyroid stimulating hormone levels in blood plasma were also measured with enzyme linked immunosorbent assay. The gene expression profile of livers was detected with gene chip analysis. Differentially expressed genes were screened out and classified according to Gene Ontology. The accuracy of results were examined with reverse transcription-polymerase chain reaction.ResultsCompared with the control group, body weight (P<0.05) and hepatic glycogen (P<0.05) were significantly lower in the Yin-deficiency-heat syndrome group. Moreover, toe temperature (P< 0.01) and triglyceride (P<0.05), Na+−K+−ATPase (P< 0.01), Mg2+−ATPase (P<0.01), T3 (P<0.05), and T4 (P< 0.01) levels were significantly higher. There were 99 differentially expressed genes in livers from the Yin-deficiency-heat syndrome group. Genes were mainly related to sterol synthesis (Pc=0.0392), defense response (Pc=0.0448), and sterol metabolism (Pc=0.0533).ConclusionAbnormal expression genes in rats with Yin-deficiency-heat syndrome prompted the synthesis and metabolism of cholesterol, increased energy consumption, and reduced defense response. This gene expression might be the molecular mechanism underlying “internal heat caused by Yin-deficiency” in the rats with Yin-deficiency-heat syndrome

XRCC1 codon 399Gln polymorphism is associated with radiotherapy-induced acute dermatitis and mucositis in nasopharyngeal carcinoma patients

BACKGROUND: To evaluate the association between single nucleotide polymorphisms (SNPs) at the 194 and 399 codons of XRCC1, and the risk of severe acute skin and oral mucosa reactions in nasopharyngeal carcinoma patients in China. METHODS: 114 patients with nasopharyngeal carcinoma were sequentially recruited in this study. Heparinized peripheral blood samples were taken for SNPs analysis before the start of radiation treatment. SNPs in XRCC1 (194Arg/Trp and 399Arg/Gln) gene were analyzed by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). Dermatitis at upper neck and oral mucositis were clinically recorded according to the Common Terminology Criteria for Adverse Events v.3.0. RESULTS: The variant allele frequencies were 0.289 for XRCC1 194Trp and 0.263 for XRCC1 399Gln. Of the 114 patients, 24 experienced grade 3 acute dermatitis and 48 had grade 3 acute mucositis. The XRCC1 399Arg/Gln was significantly associated with the development of grade 3 dermatitis (Odds Ratio, 2.65; 95% CI, 1.04–6.73; p = 0.037, χ2 = 4.357). In addition, it was also associated with higher incidence of grade 3 mucositis with a borderline statistical significance (Odds Ratio, 2.11; 95% CI, 0.951–4.66; p = 0.065, χ2 = 3.411). The relationship between XRCC1 194Arg/Trp and acute dermatitis, and mucositis was not found. CONCLUSIONS: Our investigation shows, for the first time, that patients with the XRCC1 399Arg/Gln genotype were more likely to experience severe acute dermatitis and oral mucositis. With further validation, the information can be used to determine personalized radiotherapy strategy