We investigate the Hubbard model on the anisotropic triangular lattice by means of the cellular dynamical mean-field theory. The phase diagram determined in the Hubbard interaction versus temperature plane shows novel reentrant behavior in the Mott transition due to the competition between Fermi-liquid formation and magnetic correlations under geometrical frustration. We demonstrate that the reentrant behavior is characteristic of the Mott transition with intermediate geometrical frustration and indeed consistent with recent experimental results of organic materials.

We investigate the Mott transition in the Kagomé lattice Hubbard model using a cluster extension of dynamical mean field theory. The calculation of the double occupancy, the density of states, the static and dynamical spin correlation functions demonstrates that the system undergoes the firstorder Mott transition at the Hubbard interaction U/W ∼ 1.4 (W :bandwidth). In the metallic phase close to the Mott transition, we find the strong renormalization of three distinct bands, giving rise to the formation of heavy quasiparticles with strong frustration. It is elucidated that the quasiparticle states exhibit anomalous behavior in the temperature-dependent spin correlation functions. The Kagomé lattice (Fig. 1) is another prototype of frustrated systems, which may be regarded as a twodimensional analog of the pyrochlore lattice. It is suggested that a correlated electron system on the Kagomé lattice can be an effective model of Na x CoO 2 · yH 2 O by properly considering anisotropic hopping matrix elements in the cobalt 3d orbitals [6]. The issue of electron correlations for the Kagomé lattice was addressed recently by using the FLEX approximation [7] and QMC method [8]. These studies focused on electron correlations in the metallic regime, and the nature of the Mott transition has not been clarified yet. Therefore, it is desirable to investigate the Kagomé lattice electron system with particular emphasis on the Mott transition under the influence of strong frustration.In this paper, we study the Mott transition of correlated electrons on the Kagomé lattice by means of the cellular dynamical mean field theory (CDFMT) [9]. It is shown that the metallic phase persists up to fairly large Coulomb interactions due to the frustrated lattice structure. This gives rise to the strong renormalization of three distinct bands, resulting in the multi-band quasiparticles with strong frustration near the Mott transition. In particular, we find that the quasiparticles exhibit anomalous behavior in spin correlation functions, which characterizes strong frustration in the metallic phase.We consider the standard Hubbard model with nearest-neighbor hopping on the Kagomé lattice,with n iσ = c † iσ c iσ , where c † iσ (c jσ ) creates (annihilates) an electron with spin σ at site i. We use the band width W = 6t as the energy unit. To study the Mott transition in the Kagomé lattice system, we need an efficient theoretical tool to treat both of strong correlations and geometrical frustration. The dynamical mean field theory (DMFT) [10] has given substantial theoretical progress in the field of the Mott transition but it does not incorporate spatially extended correlations. In order to treat both strong correlations and frustration, we use CDMFT, a cluster extension of DMFT, which has been successfully applied to frustrated systems such as the Hubbard model on the triangular lattice [11].In CDMFT, the original lattice is regarded as a superlattice consisting of clusters, which is then mapped onto an effective cluster model via a standard DMF...

Background and AimThe aim of this study was to elucidate the risk of subsequent biliary malignancy in patients undergoing cyst excision for congenital choledochal cysts.MethodsA retrospective analysis of 94 patients who had undergone cyst excision for congenital choledochal cysts was conducted. The median age at the time of cyst excision and median follow-up time after cyst excision were 7 years and 181 months, respectively.ResultsBiliary tract cancer developed in four patients at 13, 15, 23, and 32 years after cyst excision. The cumulative incidences of biliary tract cancer at 15, 20, and 25 years after cyst excision were 1.6%, 3.9%, and 11.3%, respectively. The sites of biliary tract cancer were the intrahepatic (n = 2), hilar (n = 1), and intrapancreatic (n = 1) bile ducts. Of the four patients with biliary tract cancer after cyst excision, three patients underwent surgical resection and one patient received chemo-radiotherapy. The overall cumulative survival rates after treatment in the four patients with biliary tract cancer were 50% at 2 years and 25% at 3 years, with a median survival time of 15 months.ConclusionsThe risk of subsequent biliary malignancy in patients undergoing cyst excision for congenital choledochal cysts seems to be relatively high in the long-term. The risk of biliary malignancy in the remnant bile duct increases more than 15 years after cyst excision. Despite an aggressive treatment approach for this condition, subsequent biliary malignancy following cyst excision for congenital choledochal cysts shows an unfavorable outcome.

Background:This study aims to explore novel microRNAs in plasma for screening cancer and predicting clinical outcomes in pancreatic cancer (PCa) patients using a microRNA array-based approach.Methods:We used the Toray 3D-Gene microRNA array-based approach to compare plasma levels between PCa patients and healthy volunteers.Results:(1) Six oncogenic microRNAs (miR-615-5p, -744, -575, -557, -675, and -550a) with high expression in plasma were selected. (2) By quantitative RT–PCR using plasma samples from 94 PCa patients and 68 healthy volunteers, a significantly higher level of plasma miR-744 in PCa patients than in healthy volunteers was validated in small-scale analysis (P=0.0038), two independent cohort analyses, and large-scale analysis (P<0.0001, AUC 0.8307). (3) miR-744 expression was significantly higher in PCa tissues (P=0.0069) and PCa cell lines (P=0.0074) than in normal tissues and fibroblasts, respectively. Preoperative plasma level of miR-744 was significantly reduced in postoperative samples (P=0.0063). (4) A high level of plasma miR-744, which was correlated with lymph node metastasis (P=0.0407) and recurrences (P=0.0376), was an independent poor prognostic factor of PCa patients after pancreatectomy (P=0.0007, HR 21.2 (3.17–436)). Furthermore, a high level of plasma miR-744 contributed to poorer progression-free survival of non-operable PCa patients who underwent gemcitabine-based chemotherapy (P=0.0533). Overexpression of miR-744 in PCa cells induced significant chemoresistance to gemcitabine in vitro.Conclusions:Plasma miR-744 might be useful biomarker for screening PCa, monitoring, and predicting poor prognosis and chemoresistance in PCa patients.

Hepatocellular carcinoma (HCC), with its high incidence and mortality rate, is one of the most common malignant tumors. Despite recent development of a diagnostic and treatment method, the prognosis of HCC remains poor. Therefore, to provide optimal treatment for each patient with HCC, more precise and effective biomarkers are urgently needed which could facilitate a more detailed individualized decision-making during HCC treatment, including the following; risk assessment, early cancer detection, prediction of treatment or prognostic outcome. In the blood of cancer patients, accumulating evidence about circulating tumor cells and cell-free nucleic acids has suggested their potent clinical utilities as novel biomarker. This concept, so-called “liquid biopsy” is widely known as an alternative approach to cancer tissue biopsy. This method might facilitate a more sensitive diagnosis and better decision-making by obtaining genetic and epigenetic aberrations that are closely associated with cancer initiation and progression. In this article, we review recent developments based on the available literature on both circulating tumor cells and cell-free nucleic acids in cancer patients, especially focusing on Hepatocellular carcinoma.