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In this work, we studied four types of cosmological models with different mechanisms driving the accelerated expansion of the universe, include Braneworld models, Chaplygin Gas models, Emergent Dark Energy models, and cosmological torsion models. Considering that the dynamics of these models at low redshifts are very similar and difficult to distinguish, we used the latest and largest UV and X-ray measurements of quasars (QSOs) observations covering the range of redshift 0.009 < z < 7.5 . However, the high intrinsic dispersion of this sample and the degeneracy between cosmological model parameters, we added 2D-BAO and 3D-BAO datasets to help us constrain the parameters of these cosmological models. Our results suggest that standard cold dark matter scenario may not be the best cosmological model preferred by the high-redshift observations. The Generalized Chaplygin Gas (GCG) and cosmological constant plus torsion (named Case II) models perform best by Akaike Information Criterion (AIC), but the Λ CDM is the best cosmological model preferred by Bayesian Information Criterion (BIC). Our work also supports that the Phenomenologically Emergent Dark Energy and cosmological torsion models may alleviate the Hubble tension, the reported value of the Hubble constant obtained from QSO+BAO datasets combination lies between Planck 2018 observations and local measurements from the SH0ES collaboration, while other cosmological models all support that the Hubble constant tends to be closer to recent Planck 2018 results, but these model are penalized by information criterion. [ABSTRACT FROM AUTHOR]

Recently, two classes of quasar samples were identified, which are promising as new cosmological probes extending to higher redshifts. The first sample uses the nonlinear relation between the ultraviolet and X-ray luminosities of quasars to derive luminosity distances, whereas the linear sizes of compact radio quasars in the second sample can serve as standardized rulers, providing angular-diameter distances. In this study, under the assumption of a flat universe, we refreshed the calibration of multiple measurements of high-redshift quasars (in the framework of a cosmological-model-independent method with the newest Hubble parameters data). Furthermore, we placed constraints on four models that characterize the cosmic equation of state (w). The obtained results show that: (1) the two quasar samples could provide promising complementary probes at much higher redshifts, whereas compact radio quasars perform better than ultraviolet and X-ray quasars at the current observational level; (2) strong degeneracy between the cosmic equation of state (w) and Hubble constant (H0) is revealed, which highlights the importance of independent determination of H0 from time-delay measurements of strongly lensed quasars; (3) together with other standard ruler probes, such as baryon acoustic oscillation distance measurements, the combined QSO+BAO measurements are consistent with the standard ΛCDM model at a constant equation of state w = −1; (4) ranking the cosmological models, the polynomial parametrization gives a rather good fit among the four cosmic-equation-of-state models, whereas the Jassal-Bagla-Padmanabhan (JBP) parametrization is substantially penalized by the Akaike Information Criterion and Bayesian Information Criterion. [ABSTRACT FROM AUTHOR]

In order to estimate cosmic curvature from cosmological probes like standard candles, one has to measure the luminosity distance D L (z) , its derivative with respect to redshift D L ′ (z) and the expansion rate H(z) at the same redshift. In this paper, we study how such idea could be implemented with future generation of space-based DECi-hertz Interferometer Gravitational-wave Observatory (DECIGO), in combination with cosmic chronometers providing cosmology-independent H(z) data. Our results show that for the Hubble diagram of simulated DECIGO data acting as a new type of standard siren, it would be able to constrain cosmic curvature with the precision of Δ Ω k = 0.09 with the currently available sample of 31 measurements of Hubble parameters. In the framework of the third generation ground-based gravitational wave detectors, the spatial curvature is constrained to be Δ Ω k = 0.13 for Einstein Telescope (ET). More interestingly, compared to other approaches aiming for model-independent estimations of spatial curvature, our analysis also achieve the reconstruction of the evolution of Ω k (z) , in the framework of a model-independent method of Gaussian processes (GP) without assuming a specific form. Therefore, one can expect that the newly emerged gravitational wave astronomy can become useful in local measurements of cosmic curvature using distant sources. [ABSTRACT FROM AUTHOR]

In this paper, the generalized equation of state (GEoS) for dark energy ( $$w_\beta =w_0-w_{\beta }[(1+z)^{-\beta }-1]/\beta $$ ) is investigated with the combined standard ruler data from the observations of intermediate-luminosity radio quasars, galaxy clusters, BAO and CMB. The constraint results show that the best-fit EoS parameters are $$w_0=-\,0.94^{+0.57}_{-0.41}$$ , $$w_\beta =-\,0.17^{+2.45}_{-4.81}$$ and $$\beta =-1.42$$ (with a lower limit of $$\beta >-\,2.70$$ at 68.3% C.L.), which implies that at early times the dark energy vanishes. In the framework of nine truncated GEoS models with different $$\beta $$ parameters, our findings present very clear evidence disfavoring the case that dark energy always dominates over the other material components in the early universe. Moreover, stringent constraints can be obtained in combination with the latest measurements of Hubble parameter at different redshifts: $$w_0=-1.01^{+0.56}_{-0.31}$$ , $$w_\beta =0.01^{+2.33}_{-4.52}$$ and $$\beta =-0.42$$ (with a lower limit of $$\beta >-2.40$$ at 68.3% C.L.). Finally, the results obtained from the transition redshift ( $$z_t$$ ) and Om( z) diagnostic indicate that: (1) The above constraints on the GEoS model agree very well with the transition redshift interval $$0.49 \le z_t \le 0.88$$ within $$1\sigma $$ error region. (2) At the current observational level, the GEoS model is practically indistinguishable from $$\Lambda $$ CDM, although a small deviation from $$\Lambda $$ CDM cosmology is present in the combined standard ruler data. [ABSTRACT FROM AUTHOR]

In this paper, we place constraints on four alternative cosmological models under the assumption of the spatial flatness of the Universe: CPL, EDE, GCG and MPC. A new compilation of 120 compact radio quasars observed by very-long-baseline interferometry, which represents a type of new cosmological standard rulers, are used to test these cosmological models. Our results show that the fits on CPL obtained from the quasar sample are well consistent with those obtained from BAO. For other cosmological models considered, quasars provide constraints in agreement with those derived with other standard probes at $$1\sigma $$ confidence level. Moreover, the results obtained from other statistical methods including figure of merit, Om( z) and statefinder diagnostics indicate that: (1) Radio quasar standard ruler could provide better statistical constraints than BAO for all cosmological models considered, which suggests its potential to act as a powerful complementary probe to BAO and galaxy clusters. (2) Turning to Om( z) diagnostics, CPL, GCG and EDE models cannot be distinguished from each other at the present epoch. (3) In the framework of statefinder diagnostics, MPC and EDE will deviate from the $$\Lambda $$ CDM model in the near future, while GCG model cannot be distinguished from the $$\Lambda $$ CDM model unless much higher precision observations are available. [ABSTRACT FROM AUTHOR]

Energetic carbon ions (CI) offer great advantages over conventional radiations such as X- or γ-rays in cancer radiotherapy. High linear energy transfer (LET) CI can induce both endoplasmic reticulum (ER) stress and autophagy in tumor cells under certain circumstances. The molecular connection between ER stress and autophagy in tumor exposed to high-LET radiation and how these two pathways influence the therapeutic effect against tumor remain poorly understood. In this work, we studied the impact of autophagy and apoptosis induced by ER stress following high-LET CI radiation on the radiosensitivity of S180 cells both in vitro and in vivo. In the in vitro experiment, X-rays were also used as a reference radiation. Our results documented that the combination of CI radiation with chloroquine (CQ), a special autophagy inhibitor, produced more pronounced proliferation suppression in S180 cells and xenograft tumors. Co-treatment with CI radiation and CQ could block autophagy through the IRE1/JNK/Beclin-1 axis and enhance apoptotic cell death via the activation of C/EBP homologous protein (CHOP) by the IRE1 pathway rather than PERK in vitro and in vivo. Thus, our study indicates that inhibiting autophagy might be a promising therapeutic strategy in CI radiotherapy via aggravating the ER stress-related apoptosis. [ABSTRACT FROM AUTHOR]

Two sets of dehydration-melting with a natural solid amphibolite, collected from North Himalayan structure zone, Tibet, have been carried out in multi-anvil apparatus at 2.0 GPa and 800–1000°C, for 12-200 h. One is keeping the pressure at 2.0 GPa and the annealing time of 12 h, changing the temperature (800–1000°C). The other is keeping the pressure at 2.0 GPa and temperature at 850°C, varying the annealing time (12–200 h). The products are inspected with microscope and electron probe. The results indicate that at 2.0 GPa, annealing time of 12 h, garnets, melts and clinopyroxenes occur in amphibolite gradually with increasing temperature and the chemical compositions of melt vary from tonalite to granodiorite, and then to tonalite. However, at 2.0 GPa and 850, with the annealing time increasing, the garnets, melts and clinopyroxenes also occur in amphibolite gradually and the chemical compositions of melt vary from tonalite to granodiorite. In both cases, melts interconnect with each other when the contents of melt are over the 5 vol.%. the viscosities of the melt produced in amphibolite at temperature higher than 850 are on a level with 104 Pa·s. The interconnected melt with such a viscosity may segregate from the source rock and form the magma over reasonable geological time. Therefore, it is believed that at the lower part of the overthickened crust, the tonlitic and granodioritic magma may be generated through the dehydration melting of amphibolite. [ABSTRACT FROM AUTHOR]

Gadolinium-based nanomaterials can not only serve as contrast agents but also contribute to sensitization in the radiotherapy of cancers. Among radiotherapies, carbon ion irradiation is considered one of the superior approaches with unique physical and biological advantages. However, only a few metallic nanoparticles have been used to improve carbon ion irradiation. In this study, gadolinium oxide nanocrystals (GONs) were synthesized using a polyol method to decipher the radiosensitizing mechanisms in non-small cell lung cancer (NSCLC) cell lines irradiated by carbon ions. The sensitizer enhancement ratio at the 10% survival level was correlated with the concentration of Gd in NSCLC cells. GONs elicited an increase in hydroxyl radical production in a concentration-dependent manner, and the yield of reactive oxygen species increased obviously in irradiated cells, which led to DNA damage and cell cycle arrest. Apoptosis and cytostatic autophagy were also significantly induced by GONs under carbon ion irradiation. The GONs may serve as an effective theranostic material in carbon ion radiotherapy for NSCLC. [ABSTRACT FROM AUTHOR]

The gas depletion factor γ (z) , i.e., the average ratio of the gas mass fraction to the cosmic mean baryon fraction of galaxy clusters, plays a very important role in the cosmological application of the gas mass fraction measurements. In this paper, using the newest catalog of 182 galaxy clusters detected by the Atacama Cosmology Telescope (ACT) Polarization experiment, we investigate the possible redshift evolution of γ (z) through a new cosmology-independent method. The method is based on non-parametric reconstruction using the measurements of Hubble parameters from cosmic chronometers. Unlike hydrodynamical simulations suggesting constant depletion factor, our results reveal the trend of γ (z) decreasing with redshift. This result is supported by a parametric model fit as well as by calculations on the reduced ACTPol sample and on the alternative sample of 91 SZ clusters reported earlier in ACT compilation. Discussion of possible systematic effects leaves an open question about validity of the empirical relation M tot – f gas obtained on very close clusters. These results might pave the way to explore the hot gas fraction within large radii of galaxy clusters as well as its possible evolution with redshift, which should be studied further on larger galaxy cluster samples in the upcoming X-ray/SZ cluster surveys. [ABSTRACT FROM AUTHOR]

In this paper, we use multi-frequency angular size measurements of 58 intermediate-luminosity quasars reaching the redshifts z∼3 and demonstrate that they can be used as standard rulers for cosmological inference. Our results indicate that, for the majority of radio-sources in our sample their angular sizes are inversely proportional to the observing frequency. From the physical point of view it means that opacity of the jet is governed by pure synchrotron self-absorption, i.e. external absorption does not play any significant role in the observed angular sizes at least up to 43 GHz. Therefore, we use the value of the intrinsic metric size of compact milliarcsecond radio quasars derived in a cosmology independent manner from survey conducted at 2 GHz and rescale it properly according to predictions of the conical jet model. This approach turns out to work well and produce quite stringent constraints on the matter density parameter Ωm in the flat ΛCDM model and Dvali-Gabadadze-Porrati braneworld model. The results presented in this paper pave the way for the follow up engaging multi-frequency VLBI observations of more compact radio quasars with higher sensitivity and angular resolution. [ABSTRACT FROM AUTHOR]

Direct measurements of Hubble parameters H(z) are very useful for cosmological model parameters inference. Based on them, Sahni, Shafieloo and Starobinski introduced a two-point diagnostic Omh2(zi,zj) as an interesting tool for testing the validity of the ΛCDM model. Applying this test they found a tension between observations and predictions of the ΛCDM model. We use the most comprehensive compilation H(z) data from baryon acoustic oscillations (BAO) and differential ages (DA) of passively evolving galaxies to study cosmological models using the Hubble parameters itself and to distinguish whether ΛCDM model is consistent with the observational data with statistical analysis of the corresponding Omh2(zi,zj) two-point diagnostics. Our results show that presently available H(z) data significantly improve the constraints on cosmological parameters. The corresponding statistical Omh2(zi,zj) two-point diagnostics seems to prefer the quintessence with w>-1 over the ΛCDM model. Better and more accurate prior knowledge of the Hubble constant, will considerably improve the performance of the statistical Omh2(zi,zj) method. [ABSTRACT FROM AUTHOR]

Heavy ion beams have advantages over conventional radiation in radiotherapy due to their superb biological effectiveness and dose conformity. However, little information is currently available concerning the cellular and molecular basis for heavy ion radiation-induced autophagy. In this study, human glioblastoma SHG44 and cervical cancer HeLa cells were irradiated with carbon ions of different linear energy transfers (LETs) and X-rays. Our results revealed increased LC3-II and decreased p62 levels in SHG44 and HeLa cells post-irradiation, indicating marked induction of autophagy. The autophagic level of tumor cells after irradiation increased in a LET-dependent manner and was inversely correlated with the sensitivity to radiations of various qualities. Furthermore, we demonstrated that high-LET carbon ions stimulated the unfolded protein response (UPR) and mediated autophagy via the UPR-eIF2α-CHOP-Akt signaling axis. High-LET carbon ions more severely inhibited Akt-mTOR through UPR to effectively induce autophagy. Thus, the present data could serve as an important radiobiological basis to further understand the molecular mechanisms by which high-LET radiation induces cell death. [ABSTRACT FROM AUTHOR]