A Yukawa-field approximation of the electrostatic free energy of a molecular solvation system with an implicit or continuum solvent is constructed. It is argued through the analysis of model molecular systems with spherically symmetric geometries that such an approximation is rational. The construction extends non-trivially that of the Coulomb-field approximation which serves as a basis of the widely used generalized Born model of molecular electrostatics. The electrostatic free energy determines the dielectric boundary force that in turn influences crucially the molecular conformation, stability, and dynamics. An explicit formula of such forces with the Yukawa-field approximation is obtained using local coordinates and shape differentiation.

BackgroundAcupuncture is beneficial for controlling chemotherapy-induced nausea and vomiting (CINV). However, the effect of different acupoint combinations on controlling CINV remains unknown. This study aims to compare the effects of distal-proximal point association and local distribution point association on controlling CINV.Methods/designThe study is a single-center, randomized controlled trial. A total of 240 participants will be randomly divided into four groups. The control group will receive standard antiemetic only, whereas three acupuncture groups will receive four electro-acupuncture treatments once a day with the standard antiemetic. Acupuncture group I and II will receive distal-proximal point association (“Neiguan (PC6) and Zhongwan (CV12)”, and “Zusanli (ST36) and CV12”, respectively); Acupuncture group III will receive local distribution point association (“Shangwan (CV13) and CV12”). The primary outcome measures are the frequency and distress of nausea and vomiting. The secondary outcome measures are the grade of constipation and diarrhea, electrogastrogram, quality of life, etc. Assessment is scheduled from the day before chemotherapy to the fifth day of chemotherapy. Follow-ups are performed from the sixth day to the twenty-first day of chemotherapy.DiscussionResults of this trial will help in evaluating the efficacy and safety of electro-acupuncture with different acupoint combinations in the management of CINV.Trial registrationClinicalTrials.gov identifier: NCT02478047.

No abstract

Cone spherical metrics are conformal metrics with constant curvature one and finitely many conical singularities on compact Riemann surfaces. By using Strebel differentials as a bridge, we construct a new class of cone spherical metrics on compact Riemann surfaces by drawing on the surfaces some class of connected metric ribbon graphs.