Numerical experiments of adjusted BSSN systems for controlling constraint violations

We present our numerical comparisons between the BSSN formulation widely used in numerical relativity today and its adjusted versions using constraints. We performed three testbeds: gauge-wave, linear wave, and Gowdy-wave tests, proposed by the Mexico workshop on the formulation problem of the Einstein equations. We tried three kinds of adjustments, which were previously proposed from the analysis of the constraint propagation equations, and investigated how they improve the accuracy and stability of evolutions. We observed that the signature of the proposed Lagrange multipliers are always right and the adjustments improve the convergence and stability of the simulations. When the original BSSN system already shows satisfactory good evolutions (e.g., linear wave test), the adjusted versions also coincide with those evolutions; while in some cases (e.g., gauge-wave or Gowdy-wave tests) the simulations using the adjusted systems last 10 times as long as those using the original BSSN equations. Our demonstrations imply a potential to construct a robust evolution system against constraint violations even in highly dynamical situations.Comment: to be published in PR

Global existence for the p-Sobolev flow

In this paper, we study a doubly nonlinear parabolic equation arising from the gradient flow for p-Sobolev type inequality, referred as p-Sobolev flow. In the special case p = 2 our theory includes the classical Yamabe flow on a bounded domain in Euclidean space. Our main aim is to prove the global existence of the p-Sobolev flow together with its qualitative properties. (C) 2021 Published by Elsevier Inc.Peer reviewe

Regularity Estimates for the p-Sobolev Flow

We study doubly nonlinear parabolic equation arising from the gradient flow for p-Sobolev type inequality, referred as p-Sobolev flow from now on, which includes the classical Yamabe flow on a bounded domain in Euclidean space in the special case . In this article we establish a priori estimates and regularity results for the p-Sobolev type flow, which are necessary for further analysis and classification of limits as time tends to infinity.Peer reviewe

First-principles study of locally disordered structures of Mn-induced GaAs(001)-(2 × 2) surface

Various atomic arrangements of the Mn-induced GaAs(001) surface, consisting of one Ga–As dimer and one Mn atom in the (2 × 2) unit, have been investigated by first-principles calculations. The most stable arrangement is reasonable in view of the classical electrostatic theory. It has been revealed that the topmost Ga–As dimers tend to be aligned along the [11 ̅0] direction, while they are less ordered along the [110] direction. These anisotropic orderings, that is, anisotropic interactions, imply that the Mn atom, which is located between the Ga–As dimers, enhances the local electrostatic interaction between the dimers along the [11 ̅0] direction, as a result of the dielectric anisotropy at the surface

Platinum and anthracycline therapy for advanced cutaneous squamous cell carcinoma

Because metastatic cutaneous squamous cell carcinoma (CSCC) is rare, standard chemotherapy has not been fully established. In Japan, combination platinum and anthracycline chemotherapy has been used for elderly patients with advanced CSCC because of its low toxicity. However, the clinical benefit of this therapy has not been fully examined. We retrospectively examined the response rate of combination platinum and anthracycline chemotherapy for metastatic CSCC. Eight patients received combination chemotherapy for metastatic lesions; there were lymph node lesions in 6 patients and skin and lung lesions in one patient each. The combination regimens were as follows: cisplatin (CDDP) (60-90 mg/m(2)/day, day 1) and adriamycin (ADM) (20-40 mg/m(2)/day, day 1 or 2) was administered in 5 patients; CDDP (10-15 mg/m(2)/day, days 1-5) and epirubicin (epi-ADM) (10-15 mg/m(2)/day, days 1-5) was administered in 2 patients; and carboplatin (CBDCA) (200-400 mg/m(2)/day, day 1) and ADM (20-40 mg/m(2)/day, day 1 or 2) was administered in one patient. The responses were as follows: complete response in 2 patients (CDDP + ADM for lung metastasis, CDDP + epi-ADM for lymph node metastasis), partial response in 1 (CDDP + ADM for lymph node metastasis), stable disease in 2, and progressive disease in 3. A durable response was observed in 2 patients showing complete responses (58 and 112 months). The clinical effect of the combination of platinum and anthracycline for metastatic CSCC was limited despite the findings of two patients showing durable complete responses.ArticleINTERNATIONAL JOURNAL OF CLINICAL ONCOLOGY. 18(3):506-509 (2013)journal articl

Single crystal synthesis and magnetic properties of Co²⁺-substituted and non-substituted magnetoplumbite-type Na–La ferrite

Single crystals of magnetoplumbite-type Na–La ferrite with and without Co doping were grown by the flux method. Wave length dispersive X-ray analysis reveals that Na and La are present in the ratio of Na/La ​= ​0.25–0.41, and Co is successfully substituted for Fe. Magnetization measurements using single crystals indicate uniaxial magnetic anisotropy in these materials. A metamagnetic transition for the hard-axis magnetization was observed in non Co²⁺-substituted samples at around 7 ​kOe due to the magnetic free energy double minima originating from the Fe²⁺ ion. The successful introduction of Co²⁺ enhances the uniaxial magnetic anisotropy favorable for permanent magnets

A System for Culturing Iris Pigment Epithelial Cells to Study Lens Regeneration in Newt

Salamanders like newt and axolotl possess the ability to regenerate many of its lost body parts such as limbs, the tail with spinal cord, eye, brain, heart, the jaw 1. Specifically, newts are unique for its lens regeneration capability. Upon lens removal, IPE cells of the dorsal iris transdifferentiate to lens cells and eventually form a new lens in about a month 2,3. This property of regeneration is never exhibited by the ventral iris cells. The regeneration potential of the iris cells can be studied by making transplants of the in vitro cultured IPE cells. For the culture, the dorsal and ventral iris cells are first isolated from the eye and cultured separately for a time period of 2 weeks (Figure 1). These cultured cells are reaggregated and implanted back to the newt eye. Past studies have shown that the dorsal reaggregate maintains its lens forming capacity whereas the ventral aggregate does not form a lens, recapitulating, thus the in vivo process (Figure 2) 4,5. This system of determining regeneration potential of dorsal and ventral iris cells is very useful in studying the role of genes and proteins involved in lens regeneration

Gi-Coupled GPCR Signaling Controls the Formation and Organization of Human Pluripotent Colonies

BACKGROUND:Reprogramming adult human somatic cells to create human induced pluripotent stem (hiPS) cell colonies involves a dramatic morphological and organizational transition. These colonies are morphologically indistinguishable from those of pluripotent human embryonic stem (hES) cells. G protein-coupled receptors (GPCRs) are required in diverse developmental processes, but their role in pluripotent colony morphology and organization is unknown. We tested the hypothesis that G(i)-coupled GPCR signaling contributes to the characteristic morphology and organization of human pluripotent colonies. METHODOLOGY/PRINCIPAL FINDINGS:Specific and irreversible inhibition of G(i)-coupled GPCR signaling by pertussis toxin markedly altered pluripotent colony morphology. Wild-type hES and hiPS cells formed monolayer colonies, but colonies treated with pertussis toxin retracted inward, adopting a dense, multi-layered conformation. The treated colonies were unable to reform after a scratch wound insult, whereas control colonies healed completely within 48 h. In contrast, activation of an alternative GPCR pathway, G(s)-coupled signaling, with cholera toxin did not affect colony morphology or the healing response. Pertussis toxin did not alter the proliferation, apoptosis or pluripotency of pluripotent stem cells. CONCLUSIONS/SIGNIFICANCE:Experiments with pertussis toxin suggest that G(i) signaling plays a critical role in the morphology and organization of pluripotent colonies. These results may be explained by a G(i)-mediated density-sensing mechanism that propels the cells radially outward. GPCRs are a promising target for modulating the formation and organization of hiPS and hES cell colonies and may be important for understanding somatic cell reprogramming and for engineering pluripotent stem cells for therapeutic applications