The detection of GW170817 and its electromagnetic counterparts allows us to constrain the equation of state of dense matter in new and complementary ways. Very stiff equations of state are ruled out ...by the upper limit on the average tidal deformability, , imposed by the detected gravitational wave signal. A lower limit, , can also be extracted by considering the large amount of ejected matter that powers the kilonova AT2017gfo. By using several microscopic nucleonic equations of state, we first confirm the existence of a monotonic relation between R1.5 (the radius of the 1.5 M configuration) and . This translates the limits on into limits on the radius: 11.8 km R1.5 13.1 km. We then show that the monotonic relation is violated if a second branch of compact stars composed of quark matter exists, as in the two-families or twin-stars scenarios. In particular, it is possible to fulfill the limits on while having R1.5 significantly smaller than 12 km. In both of these scenarios, the event GW170817/AT2017gfo originates from the merger of a hadronic star and a star containing quark matter.
Neutron stars and the nuclear equation of state Burgio, G.F.; Schulze, H.-J.; Vidaña, I. ...
Progress in particle and nuclear physics,
September 2021, 2021-09-00, Letnik:
120
Journal Article
Recenzirano
Odprti dostop
We review the current status and recent progress of microscopic many-body approaches and phenomenological models, which are employed to construct the equation of state of neutron stars. The equation ...of state is relevant for the description of their structure and dynamical properties, and it rules also the dynamics of core-collapse supernovae and binary neutron star mergers. We describe neutron star matter assuming that the main degrees of freedom are nucleons and hyperons, disregarding the appearance of quark matter. We compare the theoretical predictions of the different equation-of-state models with the currently available data coming from both terrestrial laboratory experiments and recent astrophysical observations. We also analyze the importance of the nuclear strong interaction and equation of state for the cooling properties of neutron stars. We discuss the main open challenges in the description of the equation of state, mainly focusing on the limits of the different many-body techniques, the so-called “hyperon puzzle,” and the dependence of the direct URCA processes on the equation of state.
With a large number of multi‐input multi‐output (MIMO) antennas embedded in the smartphone, much higher data throughput can be obtained for the smartphone in the MIMO operation. Furthermore, in order ...to be operational in heterogeneous networks, such as the mobile network and the wireless wide area network (WLAN), dual‐band operation of the MIMO antennas is desirable. However, owing to very limited space available in the smartphone, it has been a great challenge to dispose more MIMO antennas therein, not to mention the dual‐band MIMO antennas. To address this challenge, we present a compact decoupled 3.5/5.8 GHz (3400–3600/5725–5875 MHz) dual‐band building block formed by dual inverted‐F/loop antennas and its application for building eight dual‐band MIMO antennas for the mobile and WLAN operations. Details of the dual‐band building block and the fabricated eight MIMO antennas are described. The channel capacity of the eight MIMO antennas in an 8 × 8 MIMO system is also calculated and discussed. The obtained MIMO channel capacities are respectively about 37 and 42 bps/Hz in the 3.5 and 5.8 GHz bands, much higher than the present fourth‐generation (4G) 2 × 2 MIMO capacity (about 10 bps/Hz or less). The proposed eight MIMO antennas will hence be promising for future smartphone applications, such as in the fifth‐generation (5G) communications.
Antiretroviral drugs have dramatically improved the prognosis of HIV‐infected patients, with strikingly reduced morbidity and mortality. However, long‐term use can be associated with signs of ...premature aging. Highly active antiretroviral therapy generally comprises two nucleoside reverse transcriptase inhibitors (NRTIs), with one of three additional antiretroviral drug classes, including protease inhibitors (PIs). One commonality between mitochondrial dysfunction (induced by NRTIs) and defects in lamin A (induced by PIs) is they can cause or accelerate cellular senescence, a state of essentially irreversible growth arrest, and the secretion of many bioactive molecules collectively known as the senescence‐associated secretory phenotype (SASP). We hypothesized that senescent cells increase following treatment with certain HIV therapies. We compared the effects of two distinct HIV PIs: ritonavir‐boosted atazanavir (ATV/r) and ritonavir‐boosted darunavir (DRN/r), used in combination treatments for HIV infection. Upon ATV/r, but not DRN/r, treatment, cells arrested growth, displayed multiple features of senescence, and expressed significantly upregulated levels of many SASP factors. Furthermore, mice receiving sustained ATV/r treatment showed an increase in senescent cells and age‐related decline in physiological function. However, removing treatment reversed the features of senescence observed in vivo and cell culture. Given how these features disappeared with drug removal, certain features of senescence may not be prognostic as defined by an irreversible growth arrest. Importantly, for patients that are treated or have been treated with ATV/r, our data suggest that switching to another PI that does not promote premature aging conditions (DRN/r) may improve the associated age‐related complications.
Patients infected with HIV are at increased risk for multiple diseases of aging. Here, Kuehnemann et. al. show that treating cells and mice with protease inhibitors (PIs) used in antiretroviral therapies for HIV induces many characteristics of cellular senescence. Surprisingly, senescent phenotypes triggered by PI treatment were reversed after removal of the drug, and treated mice regained lost physiological function. These findings suggest that intermittent treatment or switching to therapies that do not cause senescence could reduce PI‐induced premature aging.
Dry eye disease (DED) is a common age-related ocular surface disease. However, it is unknown how aging influences the ocular surface microenvironment. This systematic review aims to investigate how ...the aging process changes the ocular surface microenvironment and impacts the development of DED.
An article search was performed in PubMed, EMBASE, and Web of Science. 44 studies reporting on age-related ocular changes and 14 large epidemiological studies involving the prevalence of DED were identified. 8 out of 14 epidemiological studies were further analyzed with meta-analysis. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) reporting guidelines were followed. Study-specific estimates (impact of aging on the prevalence of DED) were combined using one-group meta-analysis in a random-effects model.
Meta-analysis revealed the prevalence of DED in the elderly aged 60 years old or older was 5519 of 60107 (9.2%) and the odds ratio of aging compared to younger age was 1.313 (95% confidence interval CI; 1.107, 1.557). With increasing age, the integrity of the ocular surface and tear film stability decreased. Various inflammatory cells, including senescent-associated T-cells, infiltrated the ocular surface epithelium, lacrimal gland, and meibomian gland, accompanied by senescence-related changes, including accumulation of 8-OHdG and lipofuscin-like inclusions, increased expression of p53 and apoptosis-related genes, and decreased Ki67 positive cells.
The aging process greatly impacts the ocular surface microenvironment, consequently leading to DED.
BCL-2 family members are known to be implicated in survival in numerous biological settings. Here, we provide evidence that in injury and repair processes in lungs, BCL-2 mainly acts to attenuate ...endoplasmic reticulum (ER) stress and limit extracellular matrix accumulation. Days after an intratracheal bleomycin challenge, mice lose a fraction of their alveolar type II epithelium from terminal ER stress driven by activation of the critical ER sensor and stress effector IRE1α. This fraction is dramatically increased by BCL-2 inhibition, because IRE1α activation is dependent on its physical association with the BCL-2-proapoptotic family member BAX, and we found BCL-2 to disrupt this association
.
, navitoclax (a BCL-2/BCL-xL inhibitor) given 15-21 days after bleomycin challenge evoked strong activation of IRE-1α in mesenchymal cells and markers of ER stress, but not apoptosis. Remarkably, after BCL-2 inhibition, bleomycin-exposed mice demonstrated persistent collagen accumulation at Day 42, compared with resolution in controls. Enhanced fibrosis proved to be due to the RNAase activity of IRE1α downregulating MRC2 mRNA and protein, a mediator of collagen turnover. The critical role of MRC2 was confirmed in precision-cut lung slice cultures of Day-42 lungs from bleomycin-exposed wild-type and MRC2 null mice. Soluble and tissue collagen accumulated in precision-cut lung slice cultures from navitoclax-treated, bleomycin-challenged mice compared with controls, in a manner nearly identical to that of challenged but untreated MRC2 null mice. Thus, apart from mitochondrial-based antiapoptosis, BCL-2 functions to attenuate ER stress responses, fostering tissue homeostasis and injury repair.
The rapid solidification mechanism of Ni–Zr alloys was investigated by electromagnetic levitation (EML) technique assisted with high speed videography. A systematic analysis of the competitive growth ...mode between the primary phase and eutectic structure was conducted for three types of alloys (hypoeutectic Ni-5 at.%Zr, eutectic Ni-8.8 at.%Zr and hypereutectic Ni-13 at.%Zr alloys), whose maximum undercoolings reached up to 260, 192 and 270 K, respectively. With the increase of undercooling, the primary (Ni) phase of hypoeutectic Ni-5 at.% Zr alloy transferred from well-defined dendrites to dendrite fragments. Zr atom was difficult to diffuse into the Ni lattice because the radius of Zr atom was larger than Ni atom. For eutectic Ni-8.8 at.% Zr alloy, the competitive nucleation and growth between primary (Ni) phase and eutectics could happen when the undercooling exceeded 18 K. The refined dendrites of primary (Ni) phase and various eutectic morphologies were observed at the undercooling of 192 K. For the hypereutectic Ni-13 at.% Zr alloy, the growth morphology transition of the primary Ni5Zr intermetallic compound from faceted to non-faceted crystals occurred if the liquid alloy achieved a high undercooling. Furthermore, the atomic scale structure of the primary phase was explored by the transmission electron microscopy (TEM), which revealed that the solid solubility and the lattice constant were consistent at various undercoolings. Moreover, the compressive performance of these three type alloys were determined for EML solidified samples. Due to the effects of undercooling and composition on microstructures, Ni-5 at.%Zr and Ni-8.8 at.%Zr alloys exhibited plastic deformation at the large strain condition, while Ni-13 at.%Zr alloy showed brittle fracture feature. The compressive strength and yield strength displayed a non-linear relationship with the rise of undercooling.
•Ultrasound promotes α(Cu) nucleation rate by three orders of magnitude.•Ultrasound transforms α(Cu) growing orientation from preferred (111) plane to isotropy.•Ultrasound enhances the yield strength ...of Cu-7%Al-4%Ni-2.5%Mn alloy by three times.•Dislocation and grain strengthening are mechanisms of the alloy reinforcement.
An intensive field of 20 kHz power ultrasound with various amplitudes was applied during the solidification process of quaternary Cu-7%Al-4%Ni-2.5%Mn single-phase alloy to investigate its dynamic solidification mechanism and mechanical performance improvement. It is found that α(Cu) phase nucleates at small undercoolings and mainly grows along (111) crystalline plane direction into coarse dendrites with developed secondary arms. With the rise of amplitude, ultrasonic wave increases the nucleation rate by improving the wetting effect between alloy melt and impurities and also breaks some growing dendrites into fragments. Once the ultrasonic amplitude reaches the maximum of 15.2 µm, the prominent cavitation effect further increases the nucleation rate by three orders of magnitude, and also leads to the symmetrical distribution of temperature field, solute field and flow field in the solidification front, eventually resulting in the formation of tiny equiaxed α(Cu) grains without any obvious preferred growth orientation, inside which the solute distribution also tends to become uniform. Meanwhile, the compressive yield strength of Cu-7%Al-4%Ni-2.5%Mn alloy is significantly increased by 3 times after ultrasonic solidification. Theoretical analysis indicates that grain strengthening and dislocation strengthening are the two main reinforcement factors induced by power ultrasound.
PDF
