We present a comprehensive review of the In-Medium Similarity Renormalization Group (IM-SRG), a novel ab initio method for nuclei. The IM-SRG employs a continuous unitary transformation of the ...many-body Hamiltonian to decouple the ground state from all excitations, thereby solving the many-body problem. Starting from a pedagogical introduction of the underlying concepts, the IM-SRG flow equations are developed for systems with and without explicit spherical symmetry. We study different IM-SRG generators that achieve the desired decoupling, and how they affect the details of the IM-SRG flow. Based on calculations of closed-shell nuclei, we assess possible truncations for closing the system of flow equations in practical applications, as well as choices of the reference state. We discuss the issue of center-of-mass factorization and demonstrate that the IM-SRG ground-state wave function exhibits an approximate decoupling of intrinsic and center-of-mass degrees of freedom, similar to Coupled Cluster (CC) wave functions. To put the IM-SRG in context with other many-body methods, in particular many-body perturbation theory and non-perturbative approaches like CC, a detailed perturbative analysis of the IM-SRG flow equations is carried out. We conclude with a discussion of ongoing developments, including IM-SRG calculations with three-nucleon forces, the multi-reference IM-SRG for open-shell nuclei, first non-perturbative derivations of shell-model interactions, and the consistent evolution of operators in the IM-SRG. We dedicate this review to the memory of Gerry Brown, one of the pioneers of many-body calculations of nuclei.
We present a new ab initio method that uses similarity renormalization group (SRG) techniques to continuously diagonalize nuclear many-body Hamiltonians. In contrast with applications of the SRG to ...two- and three-nucleon interactions in free space, we perform the SRG evolution "in medium" directly in the A-body system of interest. The in-medium approach has the advantage that one can approximately evolve 3,…,A-body operators using only two-body machinery based on normal-ordering techniques. The method is nonperturbative and can be tailored to problems ranging from the diagonalization of closed-shell nuclei to the construction of effective valence-shell Hamiltonians and operators. We present first results for the energies of 4He, 16O, and 40Ca, which have accuracies comparable to coupled-cluster calculations.
The incretin hormones glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP) control glucose homeostasis through well-defined actions on the islet beta cell via ...stimulation of insulin secretion and preservation and expansion of beta cell mass. We examined the importance of endogenous incretin receptors for control of glucose homeostasis through analysis of Glp1r(-/-), Gipr(-/-), and double incretin receptor knockout (DIRKO) mice fed a high-fat (HF) diet. DIRKO mice failed to upregulate levels of plasma insulin, pancreatic insulin mRNA transcripts, and insulin content following several months of HF feeding. Both single incretin receptor knockout and DIRKO mice exhibited resistance to diet-induced obesity, preservation of insulin sensitivity, and increased energy expenditure associated with increased locomotor activity. Moreover, plasma levels of plasminogen activator inhibitor-1 and resistin failed to increase significantly in DIRKO mice after HF feeding, and the GIP receptor agonist D-Ala(2)GIP, but not the GLP-1 receptor agonist exendin-4, increased the levels of plasma resistin in studies of both acute and chronic administration. These findings extend our understanding of how endogenous incretin circuits regulate glucose homeostasis independent of the beta cell via control of adipokine secretion and energy expenditure.
To compare the effects of miglitol an alpha‐glucosidase inhibitor (AGI) absorbed in the intestine and voglibose (an AGI not absorbed) on plasma glucagon‐like peptide‐1 (GLP‐1) and gastric inhibitory ...polypeptide (GIP) levels, 26 and 24 Japanese type 2 diabetic patients were randomly assigned to receive miglitol or voglibose, respectively. After 12‐week administration of both drugs, during 2‐h meal tolerance test, plasma glucose, serum insulin and total GIP were significantly decreased and active GLP‐1 was significantly increased. Miglitol group showed a significantly lower total GIP level than voglibose group. Miglitol, but not voglibose, significantly reduced body weight (BW). In all participants, the relative change in BW was positively correlated with that of insulin significantly and of GIP with a weak tendency, but not of GLP‐1. In conclusion, both drugs can enhance postprandial GLP‐1 responses and reduce GIP responses. The significant BW reduction by miglitol might be attributable to its strong GIP‐reducing efficacy.
•Infrared free electron laser at Tokyo University of Science was employed as a tunable light source inducing isomerization and dissociation reaction of 2,3-dihydrofuran in the gas phase.•From the ...ratio of two photo isomerization products, the vibrational temperature of the hot 2,3-dihydrofuran generated through the infrared multiphoton excitation was estimated to be 1300–1500K.•The experimentally identified reaction pathways are well explainable by quantum chemical calculations.
We investigated infrared multiphoton dissociation and isomerization reactions of 2,3-dihydrofuran (2,3-DHF), cyclopropanecaboxaldehyde (CPCA) and crotonaldehyde (CA) with free electron laser at Tokyo University of Science (FEL-TUS). From 2,3-DHF as a starting material, CPCA and CA were the main isomerization products. From the measured CPCA/CA ratio, the equivalent temperature for the vibrationally hot 2,3-DHF was estimated to be 1300–1500K. From CPCA, both 2,3-DHF and CA were detected as isomerization products. No isomerization reaction from trans-CA to CPCA and 2,3-DHF was recognized and the dissociation to propylene was the dominant process. The experimentally identified reaction pathways are well explainable by quantum chemical calculations at the MP2/cc-pVDZ level.
Summary The aim of this study was to investigate the usage of tooth autotransplantation in dental clinics which offer the treatment and evaluate its practicality. Participating dentists were ...requested to provide information on transplantations they had undertaken from 1 January 1990 to 31 December 2010. A total of 614 teeth from 552 patients (37 dentists) ranging in age from 17 to 79 (mean age: 44·1) were examined. Cumulative survival rate and mean survival time were calculated using the Kaplan–Meier method, and log rank test was used for analysis of factors. The mean number of autotransplantation patients per clinic per year was 1·4. Upper third molars constituted 36·8% of donor teeth, while 37·1% were lower third molars. The lower first molar region was the most common recipient site at 32·6%, followed by the lower second molar region (28·0%). Prosthodontic treatment of transplanted teeth involved coverage with a single crown (72·5%) and abutment of bridge (18·9%). A total of 102 transplanted teeth were lost owing to complications such as attachment loss (54·9%) and root resorption (25·7%). The cumulative survival rate in cases where donor teeth had complete root formation was 90·1% at 5 years, 70·5% at 10 years and 55·6% at 15 years. The mean survival time was 165·6 months. Older age was a significant risk factor (P < 0·05) for survival. In cases where suitable donor teeth are available, autotransplantation of teeth may be a plausible treatment option for dealing with missing teeth in dental clinics.
Summary
The aim of this study was to investigate risk factors with age in the long‐term prognosis of autotransplantation of teeth with complete root formation at dental clinics. Participating ...dentists were asked to provide information on transplantations they had undertaken from 1 January 1990 to 31 December 2010. Data on a total of 708 teeth from 637 patients were collected. The data were screened to exclude patients who were under 25 or 70 years of age and over, those who were smokers or whose smoking habits were unknown, those whose transplanted teeth had incomplete root formation or multiple roots and those with fewer than 25 present teeth post‐operation. The participants in this study were 71 men (74 teeth) and 100 women (107 teeth) ranging from 25 to 69 years of age. Third molars were used as donor teeth in 89·0% of the cases. The participants were divided into three age groups of 25–39, 40–54 and 55–69. Survival analysis was conducted using the Kaplan–Meier method, and a log‐rank test revealed that there were no significant differences in age groups for men or women. Cox regression analysis indicated that the survival of transplanted teeth was not influenced by age. However, although not statistically significant, the clinical success rate was lower in the 55–69‐year‐old group than that in the younger groups. These results indicate that if suitable donor teeth are available and the conditions are right, autotransplantation is a viable treatment for missing teeth regardless of the age of the patient.
Summary The aim of this study was to investigate the risk factors affecting long‐term prognosis of autotransplantation of third molars with complete root formation in males at dental clinics. ...Participating dentists were requested to provide information on transplantations they had undertaken from 1 January 1990 to 31 December 2010. Data on a total of 708 teeth from 637 patients were collected. After data screening and elimination, participants of this study consisted of 183 teeth of 171 males ranging from 20 to 72 years of age (mean age, 44·8 years). The cumulative survival rate was 86·0% at the 5‐year mark, 59·1% at 10 years and 28·0% at 15 years. The mean survival time was 134·5 months, as calculated by the Kaplan–Meier method. Single factor analysis using the log‐rank test showed that the following factors had significant influence (P < 0·05) on survival of transplanted teeth: periodontal disease as the reason for recipient site tooth extraction, fewer than 25 present teeth and Eichner index Groups B1 to C. Cox regression analysis examined five factors: age, smoking habit, recipient site extraction caused by periodontal disease, fewer than 25 present teeth and Eichner index. This analysis showed that two of these factors were significant: fewer than 25 present teeth was 2·63 (95% CI, 1·03–6·69) and recipient site extraction caused by periodontal disease was 3·80 (95% CI, 1·61–9·01). The results of this study suggest that long‐term survival of transplanted teeth in males is influenced not only by oral bacterium but also by occlusal status.
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