Gravity is controlled by cosmological constant

We discuss a Randall-Sundrum-type two D-braneworld model in which D-branes possess different values of the tensions from those of the charges, and derive an effective gravitational equation on the branes. As a consequence, the Einstein-Maxwell theory is realized together with the non-zero cosmological constant. Here an interesting point is that the effective gravitational constant is proportional to the cosmological constant. If the distance between two D-branes is appropriately tuned, the cosmological constant can have a consistent value with the current observations. From this result we see that, in our model, the presence of the cosmological constant is naturally explained by the presence of the effective gravitational coupling of the Maxwell field on the D-brane.Comment: 10 page

Acute coronary syndrome after liver transplantation in a young primary biliary cholangitis recipient with dyslipidemia: a case report

BACKGROUND: Primary biliary cholangitis (PBC) is a chronic, progressive liver disease associated with dyslipidemia. There is a consensus that PBC does not accelerate coronary artery disease despite high cholesterol levels, so the screening test for the coronary artery is not routinely performed before liver transplantation (LT). To date, no report has described the potential risk of PBC-related dyslipidemia for developing acute coronary syndrome (ACS) after LT. CASE PRESENTATION: A 40-year-old Asian female with a known history of PBC underwent ABO-incompatible living-donor LT, with her husband as the donor. Although she had high cholesterol and triglyceride levels that were refractory to medications, she passed all routine preoperative examinations, including cardiopulmonary function tests and infection screenings. One week after LT, she developed ACS with 90% stenosis of both the left anterior descending artery and left circumflex artery. Emergent stent implantation was successfully performed followed by dual antiplatelet therapy. The long history of PBC and associated severe dyslipidemia for 10 years would have accelerated the atherosclerosis, causing latent stenosis in the coronary artery. Inapparent stenosis might have become apparent due to unstable hemodynamics during the acute phase after LT. CONCLUSIONS: PBC-related dyslipidemia potentially brings a risk for developing ACS after LT. This experience suggests that the preoperative evaluation of the coronary artery should be considered for high-risk patients, especially those who have drug-resistant dyslipidemia

One-loop corrections to AdS_5 x S^5 superstring partition function via Pohlmeyer reduction

We discuss semiclassical expansions around a class of classical string configurations lying in AdS_3 x S^1 using the Pohlmeyer-reduced from of the AdS_5 x S^5 superstring theory. The Pohlmeyer reduction of the AdS_5 x S^5 superstring theory is a gauged Wess-Zumino-Witten model with an integrable potential and two-dimensional fermionic fields. It was recently conjectured that the quantum string partition function is equal to the quantum reduced theory partition function. Continuing the previous paper (arXiv:0906.3800) where arbitrary solutions in AdS_2 x S^2 and homogeneous solutions were considered, we provide explicit demonstration of this conjecture at the one-loop level for several string solutions in AdS_3 x S^1 embedded into AdS_5 x S^5. Quadratic fluctuations derived in the reduced theory for inhomogeneous strings are equivalent to respective fluctuations found from the Nambu action in the original string theory. We also show the equivalence of fluctuation frequencies for homogeneous strings with both the orbital momentum and the winding on a big circle of S^5.Comment: 45 pages, references added, minor correction

Quantum aspects of Pohlmeyer-reduced AdS5 x S5 superstring

The AdS5 ×S5 superstring action is constructed by the Green-Schwarz formalism. For quantization it is necessary to eliminate unphysical degrees of freedom from the action by solving the Virasoro constraints and fixing the fermionic kappa-symmetry, which can be achieved by the Pohlmeyer reduction preserving the two-dimensional Lorentz invariance and the integrability. The resulting system is a gauged Wess-Zumino-Witten (gWZW) model deformed with a certain integrable potential and two-dimensional fermions. This thesis explores the quantum relation between the AdS5 × S5 superstring theory and the deformed gWZW model by evaluating the reduced theory quantum partition functions for respective classical string configurations. To understand the quantum relation between the original string theory and the reduced theory, the one-loop computation in the reduced theory is first studied for homogeneous and inhomogeneous string configurations localized in subspaces. For these classical backgrounds we demonstrate that the reduced theory partition function is exactly the same as the string theory one, then they are equivalent at one-loop level. Next we investigate the two-loop relation between the original string theory the reduced theory. The two-loop computation in the reduced theory is performed by considering the long folded string localized in AdS3. We show that the nontrivial finite terms of the two-loop partition functions of the two theories match, exhibiting the same patterns of the bosonic contributions and fermionic contributions. This is a strong indication that the AdS5 × S5 GS string and its reduced form are closely related at the quantum level

Quantum aspects of Pohlmeyer-reduced AdS5 x S5 superstring

The AdS5 ×S5 superstring action is constructed by the Green-Schwarz formalism. For quantization it is necessary to eliminate unphysical degrees of freedom from the action by solving the Virasoro constraints and fixing the fermionic kappa-symmetry, which can be achieved by the Pohlmeyer reduction preserving the two-dimensional Lorentz invariance and the integrability. The resulting system is a gauged Wess-Zumino-Witten (gWZW) model deformed with a certain integrable potential and two-dimensional fermions. This thesis explores the quantum relation between the AdS5 × S5 superstring theory and the deformed gWZW model by evaluating the reduced theory quantum partition functions for respective classical string configurations. To understand the quantum relation between the original string theory and the reduced theory, the one-loop computation in the reduced theory is first studied for homogeneous and inhomogeneous string configurations localized in subspaces. For these classical backgrounds we demonstrate that the reduced theory partition function is exactly the same as the string theory one, then they are equivalent at one-loop level. Next we investigate the two-loop relation between the original string theory the reduced theory. The two-loop computation in the reduced theory is performed by considering the long folded string localized in AdS3. We show that the nontrivial finite terms of the two-loop partition functions of the two theories match, exhibiting the same patterns of the bosonic contributions and fermionic contributions. This is a strong indication that the AdS5 × S5 GS string and its reduced form are closely related at the quantum level.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Short-Chain Fatty Acids in Gut–Heart Axis: Their Role in the Pathology of Heart Failure

Heart failure (HF) is a syndrome with global clinical and socioeconomic burden worldwide owing to its poor prognosis. Accumulating evidence has implicated the possible contribution of gut microbiota-derived metabolites, short-chain fatty acids (SCFAs), on the pathology of a variety of diseases. The changes of SCFA concentration were reported to be observed in various cardiovascular diseases including HF in experimental animals and humans. HF causes hypoperfusion and/or congestion in the gut, which may lead to lowered production of SCFAs, possibly through the pathological changes of the gut microenvironment including microbiota composition. Recent studies suggest that SCFAs may play a significant role in the pathology of HF, possibly through an agonistic effect on G-protein-coupled receptors, histone deacetylases (HDACs) inhibition, restoration of mitochondrial function, amelioration of cardiac inflammatory response, its utilization as an energy source, and remote effect attributable to a protective effect on the other organs. Collectively, in the pathology of HF, SCFAs might play a significant role as a key mediator in the gut–heart axis. However, these possible mechanisms have not been entirely clarified and need further investigation

Sex Differences in Cardiac and Clinical Phenotypes and Their Relation to Outcomes in Patients with Heart Failure

Biological sex is one of the major factors characterizing the heart failure (HF) patient phenotype. Understanding sex-related differences in HF is crucial to implement personalized care for HF patients with various phenotypes. There are sex differences in left ventricular (LV) remodeling patterns in the HF setting, namely, more likely concentric remodeling and diastolic dysfunction in women and eccentric remodeling and systolic dysfunction in men. Recently supra-normal EF (snLVEF) has been recognized as a risk of worse outcome. This pathology might be more relevant in female patients. The possible mechanism may be through coronary microvascular dysfunction and sympathetic nerve overactivation from the findings of previous studies. Further, estrogen deficit might play a significant role in this pathophysiology. The sex difference in body composition may also be related to the difference in LV remodeling and outcome. Lower implementation in guideline-directed medical therapy (GDMT) in female HFrEF patients might also be one of the factors related to sex differences in relation to outcomes. In this review, we will discuss the sex differences in cardiac and clinical phenotypes and their relation to outcomes in HF patients and further discuss how to provide appropriate treatment strategies for female patients

β₁ Adrenergic Receptor Autoantibodies and IgG Subclasses: Current Status and Unsolved Issues

A wide range of anti-myocardial autoantibodies have been reported since the 1970s. Among them, autoantibodies against the β1-adrenergic receptor (β1AR-AAb) have been the most thoroughly investigated, especially in dilated cardiomyopathy (DCM). Β1AR-Aabs have agonist effects inducing desensitization of β1AR, cardiomyocyte apoptosis, and sustained calcium influx which lead to cardiac dysfunction and arrhythmias. Β1AR-Aab has been reported to be detected in approximately 40% of patients with DCM, and the presence of the antibody has been associated with worse clinical outcomes. The removal of anti-myocardial autoantibodies including β1AR-AAb by immunoadsorption is beneficial for the improvement of cardiac function for DCM patients. However, several studies have suggested that its efficacy depended on the removal of AAbs belonging to the IgG3 subclass, not total IgG. IgG subclasses differ in the structure of the Fc region, suggesting that the mechanism of action of β1AR-AAb differs depending on the IgG subclasses. Our previous clinical research demonstrated that the patients with β1AR-AAb better responded to β-blocker therapy, but the following studies found that its response also differed among IgG subclasses. Further studies are needed to elucidate the possible pathogenic role of IgG subclasses of β1AR-AAbs in DCM, and the broad spectrum of cardiovascular diseases including HF with preserved ejection fraction