Biomedical subjects

Wei Min Liu

Publications and source records attributed to Wei Min Liu.

3 recordsLinked to original sources

PubMed2006

Koopmans' theorem for large molecular systems within density functional theory.

It is shown that in density functional theory (DFT), Koopmans' theorem for a large molecular system can be stated as follows: The ionization energy of the system equals the negative of the highest occupied molecular orbital (HOMO) energy plus the Coulomb electrostatic energy of removing an electron from the system, or equivalently, the ionization energy of an N-electron system is the negative of the arithmetic average of the HOMO energy of this system and the lowest unoccupied molecular orbital (LUMO) energy of the (N - 1)-electron system. Relations between this DFT Koopmans' theorem and its existing counterparts in the literature are discussed. Some of the previous results are generalized and some are simplified. DFT calculation results of a fullerene molecule, a finite single-walled carbon nanotube and a finite boron nitride nanotube are presented, indicating that this Koopmans' theorem approximately holds, even if the orbital relaxation is taken into consideration.

Journal Article↗

PubMed2006

Near homogeneous variation of potentials in large systems and the electronic structure of molecular quantum dots.

It is shown from Kohn-Sham (KS) density-functional theory that in a large molecular system, the Coulomb potential, molecular electrostatic potential, and KS effective potential may exhibit an approximately homogeneous variation in space, in response to a small change of the electron number. The homogeneous variation of potentials underlies the constant interaction (CI) model of quantum dots (QDs) and is related to the delocalization and invariance of KS orbitals, the identical shift of KS levels, and a natural definition of the QD capacitance. Calculation results of a fullerene C60 and a single-walled carbon nanotube are presented. Although the homogeneity of the potential variation is not perfect, it seems to lead to fairly good approximation of the CI model to the addition energy spectra of these systems.

Journal Article↗

PubMed2002

Successful pregnancy in a woman with symptomatic fibroids who underwent laparoscopic bipolar coagulation of uterine vessels.

OBJECTIVE: To report a case of successful pregnancy after laparoscopic bipolar coagulation of uterine vessels (LBCUV). DESIGN: Case report. SETTING: University-affiliated tertiary referral center. PATIENT(S): One woman, treated with LBCUV for symptomatic fibroids, who subsequently had a successful pregnancy. INTERVENTION(S): Laparoscopic bipolar coagulation of uterine arteries and anastomotic sites of uterine arteries with ovarian arteries. MAIN OUTCOME MEASURE(S): Patient evaluation by physical and ultrasound examinations. RESULT(S): Complete resolution of menorrhagia and dysmenorrhea was found after LBCUV. Reduction in fibroid size was seen by ultrasound. Two months later, the patient conceived a singleton pregnancy without the use of assisted reproductive technologies. The woman delivered by cesarean section. Neither myoma recurrence nor abnormality in uterine function was observed. CONCLUSION(S): Although fecundity- and pregnancy-related complications after LBCUV for managing uterine fibroids are still unclear, this first case report of successful pregnancy after LBCUV is promising. LBCUV might be a safe and effective alternative to myomectomy and hysterectomy.

Adult↗