Cosmological Implications of 5-dimensional Brans-Dicke Theory

The five dimensional Brans-Dicke theory naturally provides two scalar fields by the Killing reduction mechanism. These two scalar fields could account for the accelerated expansion of the universe. We test this model and constrain its parameter by using the type Ia supernova (SN Ia) data. We find that the best fit value of the 5-dimensional Brans-Dicke coupling contant is $\omega = -1.9$. This result is also consistent with other observations such as the baryon acoustic oscillation (BAO).Comment: 5 pages, 4 figures, PLB accepte

The consistency test on the cosmic evolution

We propose a new and robust method to test the consistency of the cosmic evolution given by a cosmological model. It is realized by comparing the combined quantity r_d^CMB/D_V^SN, which is derived from the comoving sound horizon r_d from cosmic microwave background (CMB) measurements and the effective distance D_V derived from low-redshift Type-Ia supernovae (SNe Ia) data, with direct and independent r_d/D_V obtained by baryon acoustic oscillation (BAO) measurements at median redshifts. We apply this test method for the Lambda-CDM and wCDM models, and investigate the consistency of the derived value of r_d/D_V from Planck 2015 and the SN Ia data sets of Union2.1 and JLA (z<1.5), and the r_d/D_V directly given by BAO data from six-degree-field galaxy survey (6dFGS), Sloan Digital Sky Survey Data Release 7 Main Galaxy Survey (SDSS-DR7 MGS), DR11 of SDSS-III, WiggleZ and Ly-alpha forecast surveys from Baryon Oscillation Spectroscopic Data (BOSS) DR-11 over 0.1<z<2.36. We find that r_d^CMB/D_V^SN for both non-flat Lambda-CDM and flat wCDM models with Union2.1 and JLA data are well consistent with the BAO and CMB measurements within 1-sigma CL. Future surveys will further tight up the constraints significantly, and provide stronger test on the consistency.Comment: 11 pages, 5 figures, 4 tables. Version accepted by PR

Antiferromagnetic fluctuations and a dominant dxyd_{xy}-wave pairing symmetry in nickelate-based superconductors

Motivated by recent experimental studies on superconductivity found in nickelate-based materials, we study the temperature dependence of the spin correlation and the superconducting pairing interaction within an effective two-band Hubbard model by the quantum Monte Carlo method. Based on parameters extracted from first-principles calculations, our intensive numerical results reveal that the pairing with a $d_{xy}$-wave symmetry firmly dominates over other pairings at low temperature, which is mainly determined by the Ni 3$d$ orbital. It is also found that the effective pairing interaction is enhanced as the on-site interaction increases, demonstrating that the superconductivity is driven by strong electron-electron correlation. Even though the $(\pi,\pi)$ antiferromagnetic correlation could be enhanced by electronic interaction, there is no evidence for long-range antiferromagnetic order exhibited in nickelate-based superconductors. Moreover, our results offer possible evidence that the pure electron correlation may not account for the charge density wave state observed in nickelates.Comment: Published versio

Signaling Pathways Associated with Cancer Stem Cells Play a Significant Role in Immunotherapy Resistance

Cancer stem cells (CSCs) are a subpopulation of tumor cells with properties of self-renewal, pluripotency, plasticity, and differentiation, and are associated with various aberrantly stimulated signaling pathways. They are responsible for tumor recurrence, distant metastasis, and drug resistance, thus inducing poor prognosis. Immunotherapy has achieved encouraging results. However, the resistance associated with its clinical application is a persistent problem in clinical and scientific researches. Increasing evidence shows that signaling pathways associated with CSCs mediate immunotherapy resistance. This review highlights the link between them, and focuses on the underlying mechanism so as to provide potential strategies and approaches for the development of new targets against the immune resistance challenge

Testing interacting dark matter and dark energy model with cosmological data

We investigate the model of dark matter-dark energy (DM-DE) interaction with coupling strength proportional to the multiplication of dark sector densities with different power indices $Q = \gamma \rho_{\rm c}^{\alpha} \rho_{\rm d}^{\beta}$. We first investigate the modification of the cosmic expansion history, and then further develop the formalism to take into account the cosmological perturbations and dark matter temperature evolution. We then use the latest observational cosmology data, including cosmic microwave background (CMB) data, baryon acoustic oscillations (BAO) data, redshift-space distortion (RSD) data and Type Ia supernovae (SNe) data to constrain the model parameters. We find in the phantom region, a positive $\alpha$ is preferred by the data above $2\, \sigma$ statistic significance. If we choose the power indices to be integers or half-integers for {\it plausible} physics of particle interaction, the allowed values within $1\, \sigma$ confidence regions are $\alpha = 0.5$ and $\beta = 0, 0.5, 1$. The inclusion of BAO and RSD data from large-scale structure and SNe data improves the constraints significantly. Our model predicts lower values of $f(z) \sigma_8(z)$ at $z<1$ comparing to $\Lambda$CDM model, which alleviates the tension of $\Lambda$CDM with various RSD data from optical galaxy surveys. Overall, the DM-DE interaction model is consistent with the current observational data, especially providing a better fit to the RSD data.Comment: 12 pages, 8 figures, PRD accepte

Combination of Immunotherapy With Targeted Therapy: Theory and Practice in Metastatic Melanoma

Metastatic melanoma is the most aggressive and obstinate skin cancer with poor prognosis. Variant novel applicable regimens have emerged during the past decades intensively, while the most profound approaches are oncogene-targeted therapy and T-lymphocyte mediated immunotherapy. Although targeted therapies generated remarkable and rapid clinical responses in the majority of patients, acquired resistance was developed promptly within months leading to tumor relapse. By contrast, immunotherapies elicited long-term tumor regression. However, the overall response rate was limited. In view of the above, either targeted therapy or immunotherapy cannot elicit durable clinical responses in large range of patients. Interestingly, the advantages and limitations of these regimens happened to be complementary. An increasing number of preclinical studies and clinical trials proved a synergistic antitumor effect with the combination of targeted therapy and immunotherapy, implying a promising prospect for the treatment of metastatic melanoma. In order to achieve a better therapeutic effectiveness and reduce toxicity in patients, great efforts need to be made to illuminate multifaceted interplay between targeted therapy and immunotherapy

Value of circulating cell-free DNA analysis as a diagnostic tool for breast cancer: a meta-analysis

OBJECTIVES: The aim of this study was to systematically evaluate the diagnostic value of cell free DNA (cfDNA) for breast cancer. RESULTS: Among 308 candidate articles, 25 with relevant diagnostic screening qualified for final analysis. The mean sensitivity, specificity and area under the curve (AUC) of SROC plots for 24 studies that distinguished breast cancer patients from healthy controls were 0.70, 0.87, and 0.9314, yielding a DOR of 32.31. When analyzed in subgroups, the 14 quantitative studies produced sensitivity, specificity, AUC, and a DOR of 0.78, 0.83, 0.9116, and 24.40. The 10 qualitative studies produced 0.50, 0.98, 0.9919, and 68.45. For 8 studies that distinguished malignant breast cancer from benign diseases, the specificity, sensitivity, AUC and DOR were 0.75, 0.79, 0.8213, and 9.49. No covariate factors had a significant correlation with relative DOR. Deek\u27s funnel plots indicated an absence of publication bias. MATERIALS AND METHODS: Databases were searched for studies involving the use of cfDNA to diagnose breast cancer. The studies were analyzed to determine sensitivity, specificity, positive likelihood ratio, negative likelihood ratio, diagnostic odds ratio (DOR), and the summary receiver operating characteristic (SROC). Covariates were evaluated for effect on relative DOR. Deek\u27s Funnel plots were generated to measure publication bias. CONCLUSIONS: Our analysis suggests a promising diagnostic potential of using cfDNA for breast cancer screening, but this diagnostic method is not yet independently sufficient. Further work refining qualitative cfDNA assays will improve the correct diagnosis of breast cancers

Cosmic Radio Background from Primordial Black Holes at Cosmic Dawn

The presence of an extra radio background besides the cosmic microwave background has important implications for the observation of the 21-cm signal during the cosmic Dark Ages, Cosmic Dawn, and epoch of Reionization. The strong absorption trough found in the 21-cm global spectrum measured by the EDGES experiment, which has a much greater depth than the standard model prediction, has drawn great interest to this scenario, but more generally it is still of great interest to consider such a cosmic radio background (CRB) in the early Universe. To be effective in affecting the 21-cm signal at early time, such a radio background must be produced by sources which can emit strong radio signals but modest amount of X-rays, so that the gas is not heated up too early. We investigate the scenario that such a radio background is produced by the primordial black holes (PBHs). For PBH with a single mass, we find that if the PBHs' abundance $\log(f_{\rm PBH})$ (ratio of total PBH mass density to total matter density) and mass satisfy the relation $\log(f_{\rm PBH}) \sim -1.8\log(M_\bullet/{\rm M}_{\odot})-3.5$ for $1\,{\rm M}_\odot \lesssim M_\bullet \lesssim 300 {\rm M}_\odot$, and have jet emission, they can generate a CRB required for reproducing the 21-cm absorption signal seen by the EDGES. The accretion rate can be boosted if the PBHs are surrounded by dark matter halos, which permits lower $f_{\rm PBH}$ value to satisfy the EDGES observation. In the latter scenario, since the accretion rate can evolve rapidly during the Cosmic Dawn, the frequency (redshift) and depth of the absorption trough can determine the mass and abundance of the PBHs simultaneously. For absorption trough redshift $\sim$ 17 and depth $\sim -500$ mK, it corresponds to $M_\bullet \sim 1.05\,{\rm M}_{\odot}$ and $f_{\rm PBH}\sim 1.5\times10^{-4}$.Comment: 16 pages, 13 figures, accepted for publication in PR

Anomalous anisotropic cross-correlations between WMAP CMB maps and SDSS galaxy distribution and implications on the dark flow scenario

We search for the dark flow induced diffuse kinetic Sunyaev Zel'dovich (kSZ) effect through CMB-galaxy cross correlation. Such angular correlation is anisotropic, with a unique $cos(theta_DF)$ angular dependence and hence can be distinguished from other components. Here, $theta_DF$ is the angle between the opposite dark flow direction and the direction of the sky where the correlation is measured. We analyze the KIAS-VAGC galaxy catalog of SDSS-DR7 and the WMAP seven-year temperature maps, applying an unbiased optimal weighting scheme to eliminate any statistically isotropic components and to enhance the dark flow detection signal. Non-zero weighted cross correlations are detected at 3.5 sigma for the redshift bin z<0.1 and at 3 sigma for the bin 0.1<z<0.2, implying the existence of statistically anisotropic components in CMB. However, further analysis does not support the dark flow explanation. The observed directional dependence deviates from the $\propto cos(theta_DF)$ relation expected, and hence can not be explained by the presence of a single dark flow, and if the observed cross correlation is generated by the dark flow induced kSZ effect, the velocity would be too high (> 6000 km/s). We report this work as the first attempt to search for dark flow through weighted CMB-galaxy cross correlation and to draw the attention on the sources of the detected anomalous CMB-galaxy cross correlation.Comment: 8 pages, 8 figures, ApJ accepte