Guidelines for avoiding risks resulting from discontinuation of nucleoside/nucleotide analogs in patients with chronic hepatitis B

Nucleoside/nucleotide analogs (NUC) can lead to rapid reduction in hepatitis B virus (HBV) DNA levels in blood and normalization of alanine aminotransferase levels in many patients. They also provide histological improvement which results in a reduction in liver carcinogenesis. However, it is difficult to completely remove viruses even by NUC and there are some problems such as emergence of resistant strains and hepatitis relapse resulting from discontinuation of treatment. One of the reasons for this is that NUC reduce the HBV DNA level in blood but have almost no effects on the HBV cccDNA level in hepatocyte nuclei, which are the origins of HBV replication, and HBV cccDNA remains for a long period. For treatment with NUC in patients with hepatitis B, it is considered that NUC should not be easily discontinued because discontinuation often results in hepatitis relapse. However, it has not been clearly revealed when and how hepatitis relapses after discontinuation. Although some patients do not experience hepatitis relapse after discontinuation of NUC, or experience only mild relapse and finally achieve a stable condition, it has not been established how to identify such patients efficiently. We performed research to investigate characteristics of the course after discontinuation of treatment and definition of hepatitis relapse and estimate the relapse rate. Guidelines for avoiding risks resulting from discontinuation of NUCs 2012 is summarized based on the study results. Because the guidelines are written in Japanese, we explain them in English as a review article.ArticleHEPATOLOGY RESEARCH. 44(1):1-8 (2014)journal articl

Calderon-preconditioned boundary integral equations of the Burton-Miller type for transmission problems

This paper proposes well-conditioned boundary integral equations based on the Burton-Miller method for solving transmission problems. The Burton-Miller method is widely accepted as a highly accurate numerical method based on the boundary integral equation for solving exterior wave problems. While this method can also be applied to solve the transmission problems, a straightforward formulation may yield ill-conditioned integral equations. Consequently, the resulting linear algebraic equations may involve a coefficient matrix with a huge condition number, leading to poor convergence of Krylov-based linear solvers. To address this challenge, our study enhances Burton-Miller-type boundary integral equations tailored for transmission problems by exploiting the Calderon formula. In cases where a single material exists in an unbounded host medium, we demonstrate the formulation of the boundary integral equation such that the underlying integral operator ${\cal A}$ is spectrally well-conditioned. Specifically, ${\cal A}$ can be designed in a simple manner that ensures ${\cal A}^2$ is bounded and has only a single eigenvalue accumulation point. Furthermore, we extend our analysis to the multi-material case, proving that the square of the proposed operator has only a few eigenvalues except for a compact perturbation. Through numerical examples of several benchmark problems, we illustrate that our formulation reduces the iteration number required by iterative linear solvers, even in the presence of material junction points; locations where three or more sub-domains meet on the boundary

A note on no-hair properties of static black holes in four and higher dimensional spacetimes with cosmological constant

We study no-hair properties of static black holes in four and higher dimensional spacetimes with a cosmological constant. For the vanishing cosmological constant case, we show a no-hair theorem and also a no-short-hair theorem under certain conditions for the energy-momentum of matter fields. For the positive cosmological constant case, we discuss conditions for hairy static black holes to exist in terms of the energy density of matter fields evaluated at the black hole horizon and the cosmological horizon. For the negative cosmological constant case, we study conditions for hairy black holes by presenting a no-hair theorem in which the asymptotic structure is assumed to be determined by the true cosmological constant

On Vortex-induced Oscillation of Bluff Bodies

This paper considers the classification of vortex-induced oscillations and the geometrical shape effects on them. The following points are considered : 1) the flow pattern around the section, 2) the relation between the onset critical reduced velocity and the critical reduced velocity which is defined as the reciprocal of the Strouhal Number and 3) the relation between the two onset critical reduced velocities of vortex-induced oscillations (in the heaving and the torsional mode). Also, an estimation of “the onset critical reduced velocity” and “the allowable amplitude concerning the fatigue failure of steel” of vortex-induced oscillation is described

Primary results of sedimetological research on the upper Jurassic to lower Cretaceous carbonate rocks in NW Zagros Mountains, Iran

The upper Jurassic-lower Cretaceous carbonate extensively distributed in Zagros Mountains (southern Iran) is correlated to hydrocarbon reservoir rocks, however has not been studied with sedimentological aspects. The studied section of about 1000 m thick exposed in Kuh-d-Yaghma (Aligdaz Province) mainly consists of shallow marine facies exhibiting sedimentary structures, such as paleosols, paleokarsts, biostromes, and stromatolites. The section was subdivided into nine units based on the results of observation of outcrops and thin sections. Depositional ages were estimated by fossil occurrences and strontium stable isotope. Units 1 and 2 represent subaerial-meteoric diagenetic structures (paleosols. paleokarsts, and banded cements) and dolomite of a mixed-water origin. Originally, the dolostone was highly-permeable coarse-grained sediment, in which dolomitization selectively subjected. These diagenetic processes may have been associated with global sea-level low or a regional tectonic event during Kimmeridgian, and formed lithified substrate, which is suitable for sedentary organisms. Unit 3 abundantly yields potential reef-building organisms, such as stromatoporoids, corals, and calcareous algae. However, the dominant constituents are broken uniserial branching stromatoporoids, their constructions should be regarded as biostromes and did not form reef framework. Fossil association and strontium isotopic ratio indicate that this unit was deposited in Tithonian. Units 4～7 are alternations of two deeper and two shallower facies. The deeper units (units 4 and 6) mainly consists of micritic limestone with biofacies characterized by ostracodes, bryozoans, and sponge spicules. The shallower units (units 5 and 7) represents stromatolites, oncoids, and ooids with rich assemblage of calcareous algae. Jurassic/Cretaceous boundary was placed in unit 5. First appearance of orbitolinid foraminifers at the base of unit 7 was interpreted to correspond to the base of Barremian. Units 8 and 9 consist of four upward-shallowing sequences. The base of each cycle consists of thinly bedded limestone containing brachiopod shell, and change into thickly bedded and massive limestone with shallow marine stromatolies and fauna, such as corals and rudists. Gradual decrease in thickness of the sequence indicates that the platform was in progradation due to accumulation of the carbonate deposits