Large-scale array for radio astronomy on the farside (LARAF).

At the Royal Society meeting in 2023, we have mainly presented our lunar orbit array concept called DSL, and also briefly introduced a concept of a lunar surface array, LARAF. As the DSL concept had been presented before, in this article, we introduce the LARAF. We propose to build an array in the far side of the Moon, with a master station which handles the data collection and processing, and 20 stations with maximum baseline of 10 km. Each station consists of 12 membrane antenna units, and the stations are connected to the master station by power line and optical fibre. The array will make interferometric observation in the 0.1-50 MHz band during the lunar night, powered by regenerated fuel cells. The whole array can be carried to the lunar surface with a heavy rocket mission, and deployed with a rover in eight months. Such an array would be an important step in the long-term development of lunar-based ultralong wavelength radio astronomy. It has a sufficiently high sensitivity to observe many radio sources in the sky, though still short of the dark age fluctuations. We discuss the possible options in the power supply, data communication, deployment etc. This article is part of a discussion meeting issue 'Astronomy from the Moon: the next decades (part 2)'.

Enhanced Luminescence of Dye-Decorated ZIF-8 Composite Films via Controllable D-A Interactions for White Light Emission.

Metal-organic frameworks (MOFs) constructed by metal ions/clusters and organic linkers are used to encapsulate fluorescent guest species with aggregation-caused quenching (ACQ) effects to enhance fluorescence properties due to their porous structures and high specific surface areas. However, there would be a problem of matching between MOF pores and guest molecules' sizes. In this paper, amorphous ZIF-8 was modified by carboxyl functional groups (H3BTC-ZIF-8) via introducing the 1,2,4-benzenetricarbonic acid (H3BTC) ligand into the ZIF-8 sol system. Moreover, H3BTC-ZIF-8 was used for the loading of organic fluorescent dyes rhodamine 6G (R6G) and coumarin 151 (C151) to prepare R6G/C151/H3BTC-ZIF-8 composite films. A white-light-emitting composite film (R6G/C151/H3BTC-ZIF-8) with CIE coordinates of (0.323, 0.347) was successfully prepared by compounding fluorescent dyes (R6G and C151) with H3BTC-modified ZIF-8, whose photoluminescence quantum yield (PLQY) can reach 64.0%. It was higher than the PLQY of the composite films prepared by crystalline ZIF-8 (40.2%) or amorphous ZIF-8 without H3BTC (48.0%) compounded with the same concentrations of dyes. The fluorescence enhancement was probably attributed to an increased amount of active sites of H3BTC-modified ZIF-8 interacting with dyes C151 and R6G. This can form hydrogen bonds between H3BTC-ZIF-8 and C151, and weak electron donor-acceptor (D-A) interactions between H3BTC-ZIF-8 and R6G molecules, respectively, thus enhancing the interactions between dyes and ZIF-8 and reducing the ACQ effect existing between dye molecules. Therefore, this strategy could provide an important guidance to develop white-light-emissive materials.

Latent profiles of nurses' moral resilience and compassion fatigue.

BACKGROUND: Compassion fatigue is often associated with moral distress in the nursing practice among registered nurses. Moral resilience is an important ability to maintain, restore, or promote their physical and mental health in response to ethical dilemmas in nursing. Moral resilience can be utilized as a potential solution to aid registered nurses in effectively managing compassion fatigue. AIM: To identify latent profiles of moral resilience among registered nurses and to explore the relationships of these profiles with compassion fatigue. RESEARCH DESIGN: From August 2022 to December 2022, 569 nurses were recruited in two general hospitals, in China. A Rushton Moral Resilience Scale and the Chinese version of Compassion Fatigue-Short Scale were given to the participants. A latent profile analysis was conducted to explore moral resilience latent profiles. Predictors of profiles membership was evaluated using multinomial logistic regression analysis, and the compassion fatigue scores of each latent profile were compared using a one-way analysis of variance. ETHICAL CONSIDERATIONS: We obtained ethical approval from the Institution Review Board of Xiangya School of Nursing, Central South University (IRB No. E202293, approved 15/July/2022). RESULTS: A four-profile moral resilience model best fit the data. Different levels and shapes differentiated the four profiles: high moral resilience (28.7%), moderate moral resilience (52.3%), low responses and high efficacy (16.2%), and low moral resilience (2.8%). Nurses with bachelor's degrees were more likely to belong to the high moral resilience (OR = 0.118, p = .038) and moderate moral resilience (OR = 0.248, p = .045); Nurses who were divorced or separated (OR = 11.746, p = .025) and very dissatisfied with their work (OR = 0.001, p = .049) were more probably belonging to low moral resilience. Nurses who had received ethical training in the hospital were more likely involved in high moral resilience (OR = 5.129, p = .003) and low responses and high efficacy (OR = 5.129, p = .003). In each profile of moral resilience, compassion fatigue was experienced differently by the participants (F = 13.05, p < .001). CONCLUSIONS: Developing and implementing interventions tailored to each nurse's moral resilience profile would maximize interventions' effectiveness and reduce nurses' compassion fatigue.

A simple method for simultaneous determination of organophosphate esters and their diester metabolites in dairy products and human milk by using solid-phase extraction coupled to liquid chromatography-tandem mass spectrometry.

Organophosphate esters (OPEs) and their diester metabolites have been frequently found in various environmental matrices and regarded as emerging environmental pollutants, whereas data on their occurrence in foods and human matrices are still limited. In this study, a novel and simple procedure was developed to simultaneously determine 14 OPEs and 6 diester metabolites in dairy products and human milk. After enzymatic hydrolysis by ß-glucuronidase/arylsulfatase, a freeze-dried milk sample was extracted with acetonitrile and purified by solid-phase extraction. Subsequently, all target compounds were determined by HPLC-ESI-MS/MS. Linearity, limits of detection (LODs), recovery, precision, and matrix effects of the proposed methodology were validated, and the parameters of HPLC-ESI-MS/MS were optimized. LODs for OPEs and their diester metabolites were from 0.001 to 0.02 ng/mL, and limits of quantification (LOQs) were 0.01-0.3 ng/mL. Average recoveries at two spiked levels ranged between 67.3 and 121%, with relative standard deviation lower than 20.7%. A test for matrix effects showed that most analytes presented signal suppression, and isotopically labeled ISs were essential for compensating for the matrix effects. Finally, OPEs and their metabolites both showed high detecting frequencies in real samples, which indicated that these emerging pollutants were ubiquitous in foods and the human body, and the impact of the diester metabolites on population exposure must be included in exposure assessment.

Calunduloside E inhibits HepG2 cell proliferation and migration via p38/JNK-HMGB1 signalling axis.

High-mobility group box 1 (HMGB1), a highly conserved chromosome protein, is considered as a potential therapeutic target and novel biomarker because of its regulation in the proliferation and metastasis of Hepatocellular carcinoma (HCC). Calenduloside E (CE), a natural active product, has been reported to anti-cancer effect. However, the role and underlying molecular mechanism of CE in HCC is still unclear. The purpose of this study is to investigate the effects of CE on the proliferation and migration of HCC, and then explore the possible underlying molecular mechanism. HepG2 cells were treated with CE or transfected with HMGB1 shRNA plasmids, EdU and colony formation assays were used to detect cell proliferation ability. Wound healing and transwell assays were used to determine the role of CE in cell migration. The expression of Cyclins, PCNA, MMPs, HMGB1, N-cadherin, E-cadherin and phosphorylation of p38, ERK and JNK were all detected using Western blotting. Our results showed that CE inhibited HepG2 cells proliferation and migration in a dose dependent manner; reduced the expression levels of Cycins, PCNA, HMGB1, MMPs and N-cadherin; up-regulated E-cadherin expression; enhanced the phosphorylation of p38 and JNK signalling pathways. Blocking the activation of p38 and JNK obviously reversed CE-mediated inhibitory effects on HepG2 cell proliferation and migration; reversed CE-induced down-regulation of Cyclins, PCNA, MMPs, N-cadherin and HMGB1, as well as E-cadherin up-regulation. In conclusion, our study suggested that CE reduces the expression levels of Cyclins, MMPs and epithelial-mesenchymal transformation (EMT) through p38/JNK-HMGB1 signaling axis and then inhibits HepG2 cells proliferation and migration in HepG2 cells. This study provides a new perspective for the anti-tumour molecular mechanism of CE in HCC.

Discovering the sky at the longest wavelengths with a lunar orbit array.

Due to ionosphere absorption and the interference of natural and artificial radio emissions, astronomical observation from the ground becomes very difficult at the wavelengths of decametre or longer, which we shall refer to as the ultralong wavelengths. This unexplored part of the electromagnetic spectrum has the potential for great discoveries, notably in the study of cosmic dark ages and dawn, but also in heliophysics and space weather, planets and exoplanets, cosmic ray and neutrinos, pulsar and interstellar medium (ISM), extragalactic radio sources, and so on. The difficulty of the ionosphere can be overcome by space observation, and the Moon can shield the radio frequency interferences (RFIs) from the Earth. A lunar orbit array can be a practical first step to opening up the ultralong wave band. Compared with a lunar surface observatory on the far side, the lunar orbit array is simpler and more economical, as it does not need to make the risky and expensive landing, can be easily powered with solar energy, and the data can be transmitted back to the Earth when it is on the near-side part of the orbit. Here, I describe the discovering sky at the longest wavelength (DSL) project, which will consist of a mother satellite and 6-9 daughter satellites, flying on the same circular orbit around the Moon, and forming a linear interferometer array. The data are collected by the mother satellite which computes the interferometric cross-correlations (visibilities) and transmits the data back to the Earth. The whole array can be deployed on the lunar orbit with a single rocket launch. The project is under intensive study in China. This article is part of a discussion meeting issue 'Astronomy from the Moon: the next decades'.

Dense magnetized plasma associated with a fast radio burst.

Fast radio bursts are bright, unresolved, non-repeating, broadband, millisecond flashes, found primarily at high Galactic latitudes, with dispersion measures much larger than expected for a Galactic source. The inferred all-sky burst rate is comparable to the core-collapse supernova rate out to redshift 0.5. If the observed dispersion measures are assumed to be dominated by the intergalactic medium, the sources are at cosmological distances with redshifts of 0.2 to 1 (refs 10 and 11). These parameters are consistent with a wide range of source models. One fast burst revealed circular polarization of the radio emission, but no linear polarization was detected, and hence no Faraday rotation measure could be determined. Here we report the examination of archival data revealing Faraday rotation in the fast radio burst FRB 110523. Its radio flux and dispersion measure are consistent with values from previously reported bursts and, accounting for a Galactic contribution to the dispersion and using a model of intergalactic electron density, we place the source at a maximum redshift of 0.5. The burst has a much higher rotation measure than expected for this line of sight through the Milky Way and the intergalactic medium, indicating magnetization in the vicinity of the source itself or within a host galaxy. The pulse was scattered by two distinct plasma screens during propagation, which requires either a dense nebula associated with the source or a location within the central region of its host galaxy. The detection in this instance of magnetization and scattering that are both local to the source favours models involving young stellar populations such as magnetars over models involving the mergers of older neutron stars, which are more likely to be located in low-density regions of the host galaxy.

Rapid determination of 13 organophosphorus flame retardants in milk by using modified quick, easy, cheap, effective, rugged, and safe technique, solid-phase extraction, and HPLC-MS/MS.

Organophosphorus flame retardants are a class of widely used plasticizers and flame retardants. In this study, an analytical methodology for the simultaneous determination of 13 organophosphorus flame retardants in milk was developed by using high-performance liquid chromatography-tandem mass spectrometry in combination with a modified quick, easy, cheap, effective, rugged, and safe technique and solid-phase extraction. The experimental parameters of the sample purification procedure and high-performance liquid chromatography-tandem mass spectrometry were optimized. The developed method was validated in terms of linearity, limits of detection, recovery, and precision. The method showed a linear response in the 1-100 ng/mL concentration range and the limits of detection ranged from 0.001 to 0.3 ng/mL. The mean recoveries for most organophosphorus flame retardants were in the ranges of 75.0-115.8% (spiked at 2.5 ng/mL) and 76.7-124.8% (spiked at 25 ng/mL), with relative standard deviations of <13.09%. The developed methodology was successfully applied to the analysis of nine human milk samples and nine commercial cow milk samples. Eleven organophosphorus flame retardants were detected in the human milk samples, with median concentrations that ranged from lower than the limit of detection to 1.47 ng/mL, and only nine organophosphorus flame retardants were detected in cow milk samples, with median levels of <0.32 ng/mL.

The role of prepotent response inhibition and interference control in depression.

INTRODUCTION: The ability to suppress inappropriate prepotent response and to overcome the interference of irrelevant information are two important components of inhibitory control. Little is known, however, about the relevant contributions in these two components of inhibitory control to depression. The aim of the present study was to assess the prepotent response inhibition and interference control simultaneously in a group of patients diagnosed with major depression disorder (MDD). METHODS: A clinical group of patients with MDD (n = 41) and a control group of healthy volunteers (n = 39) were recruited and assessed using the stop-signal task and the Flanker task respectively. RESULTS: The results showed longer stop-signal reaction time in patients with MDD in the stop-signal task. Regarding the interference control function, the analysis showed the response accuracy under the incongruent condition was significantly lower in patients with MDD than healthy individuals. CONCLUSIONS: In conclusion, patients with MDD showed impairments both in prepotent response inhibition and interference control. The present findings provide a better understanding of the mechanism of depression-related deficits in inhibition and have great implications for the development of cognitive training programmes to remediate cognitive dysfunction in depression.

Deficits in maintenance and interference control of working memory in major depression: evidence from the visuospatial change detection task.

INTRODUCTION: Recent theories in cognitive psychology suggest that working memory (WM) processing involves a set of specific functions, in particular the WM functions of maintenance and interference control. Previous findings on WM impairments in patients with major depressive disorder (MDD) had been inconsistent, partly because earlier studies did not take into account these two different functions of WM. METHOD: Forty-two participants with MDD and 39 controls completed the visuospatial change detection task. We estimated the WM function of maintenance, based on performance in trials using the targets only, and the WM function of interference control, based on performance in trials with distractor rectangles. RESULTS: Our results showed that participants with MDD had poorer WM function of maintenance and interference control than controls. However, the results of filtering efficiency did not show significant group difference, thus patients with MDD showed comparable impairments in WM function of maintanance as well as in WM function of interference control. CONCLUSION: Our findings suggested that patients with MDD appear to show generalised impairments on visuospatial WM function of maintenance and interference control. Future studies should use refined paradigms to assess the different functions of WM and their distinctive contributions to symptomatology of depression.

Peering into the dark (ages) with low-frequency space interferometers: Using the 21-cm signal of neutral hydrogen from the infant universe to probe fundamental (Astro)physics.

The Dark Ages and Cosmic Dawn are largely unexplored windows on the infant Universe (z ~ 200-10). Observations of the redshifted 21-cm line of neutral hydrogen can provide valuable new insight into fundamental physics and astrophysics during these eras that no other probe can provide, and drives the design of many future ground-based instruments such as the Square Kilometre Array (SKA) and the Hydrogen Epoch of Reionization Array (HERA). We review progress in the field of high-redshift 21-cm Cosmology, in particular focussing on what questions can be addressed by probing the Dark Ages at z > 30. We conclude that only a space- or lunar-based radio telescope, shielded from the Earth's radio-frequency interference (RFI) signals and its ionosphere, enable the 21-cm signal from the Dark Ages to be detected. We suggest a generic mission design concept, CoDEX, that will enable this in the coming decades.

Role of crustacean female sex hormone (CFSH) in sex differentiation in early juvenile mud crabs, Scylla paramamosain.

Recent studies have shown that crustacean female sex hormone (CFSH) is involved in the development of reproductive phenotype. In the present study, observation of sexually dimorphic traits revealed that gender could be distinguished from the third stage juveniles onwards in the mud crab, Scylla paramamosain. Sp-cfsh expression levels were analyzed in early juveniles. The results showed that, Sp-cfsh expression levels differed among individuals at post-molt of the first stage and second stage, and significantly different between the two sexes at post-molt of the third stage, which suggested that Sp-cfsh might participate in the sex differentiation in early juveniles. The expression of Sp-cfsh was examined during the molting cycle at the third stage juveniles, and the results showed that it was highest at the pre-molt stage. Based on the results, the expression of Sp-cfsh at pre-molt stage was further analyzed between the sexes from the third stage to the fifth stage, and it was found that the expression of Sp-cfsh was similar between two sexes at the third stage and the fourth stage; whereas at the fifth stage, when the gonopores occurred, the expression of Sp-cfsh significantly increased in females but decreased in males; suggesting that the expression of Sp-cfsh could influence the formation of gonopores. Finally, the role of Sp-cfsh in the reproductive phenotypes was confirmed through RNA interference knockdown. The combined results suggest that CFSH is involved in the regulation of sex differentiation of early juvenile in S. paramamosain.

A novel crustacean hyperglycemic hormone (CHH) from the mud crab Scylla paramamosain regulating carbohydrate metabolism.

Crustacean hyperglycemic hormone (CHH) plays a crucial role in regulating carbohydrate metabolism in crustaceans. In this study, a new cDNA encoding type I CHH peptide, termed Sp-CHH3, was isolated from the mud crab Scylla paramamosain and its potential functions were investigated. The full length cDNA of Sp-CHH3 was identified as encoding a 127-aa precursor composed of a 27-aa signal peptide, a 23-aa CHH precursor-related peptide and a 75-aa mature peptide with a typical motif of CHH. Phylogenic analysis suggested that, Sp-CHH3 is a previously unreported CHH from S. paramamosain. Tissue distribution analysis showed that Sp-CHH3 was mainly expressed in the eyestalk ganglia, thoracic ganglia, stomach and the ovary. A RNA interference experiments showed that after injection of Sp-CHH3-targeted dsRNA, both the level of Sp-CHH3 expression in the eyestalk ganglia and hemolymph glucose level decreased significantly. A further short-term starvation experiments demonstrated that, the level of Sp-CHH3 detected in the eyestalk ganglia was significantly up-regulated at the 12th h of starvation, it then fell back at the 24th h of starvation and subsequently remained relative stability between the 24th to 96th h of starvation. The hemolymph glucose level decreased significantly (P < .05) at each sampling time during the 96 h starvation duration when compared to that of 0 h (prior to starvation) and the overall trend was largely correlated with the level of Sp-CHH3 expression in the eyestalk ganglia. In summary, the results suggest that Sp-CHH3 plays a functional role in regulating carbohydrate metabolism in S. paramamosain.

Glycomimetic-Conjugated Photosensitizer for Specific Pseudomonas aeruginosa Recognition and Targeted Photodynamic Therapy.

Due to the rapid development of bacterial resistance, there is an urgent need to explore new antibacterial agents to substitute for traditional antibiotic therapy. Photodynamic therapy has been identified as a promising bactericidal method to conquer antibiotic-resistant pathogens. To solve the problem of photosensitizer damage to normal tissues in vivo, we developed a boron-dipyrrolemethene (BODIPY)-based glycosylated photosensitizer for ablating Pseudomonas aeruginosa ( P. aeruginosa). This glycosylated photosensitizer exhibited good water solubility and generated 1O2 rapidly in an aqueous solution under light exposure. The photosensitizer did not cause detectable toxicity to human cells in the dark. Importantly, the photosensitizer was able to selectively attach to P. aeruginosa over normal cells, thus resulting in effective pathogen ablation by reactive oxygen species. Moreover, the photosensitizer inhibited over 90% of the biofilm formation produced by P. aeruginosa. The results indicate that the design of the macromolecular photosensitizer-induced bacterial death and inhibited biofilm formation provide a novel strategy for overcoming bacterial infection.

A Water-Soluble Galactose-Decorated Cationic Photodynamic Therapy Agent Based on BODIPY to Selectively Eliminate Biofilm.

A multitude of serious chronic infections are involved in bacterial biofilms that are difficult to eradicate. Here, a water-soluble galactose-functionalized cationic 4,4-difluoro-4-bora-3a,4a-diaza-s-indacene (BODIPY)-based photodynamic therapy agent was synthesized for selectively eliminating the bacterial biofilm. These conjugates can capture bacteria to form aggregations through electrostatic interaction and then generate a large number of reactive oxygen species (ROS) under visible light irradiation to kill the bacteria without the emergence of bacterial resistance. Simultaneously, this agent could effectively inhibit and eradicate both Gram-positive and Gram-negative bacterial biofilms. The in-depth analysis of the antimicrobial mechanism confirmed that the conjugates can quickly bind on the bacterial surface, irreversibly disrupt the bacterial membrane, and distinctly inhibit intracellular enzyme activity, ultimately leading to the bacterial death. Importantly, these conjugates are highly selective toward bacterial cells over mammalian cells as well as no cytotoxicity to A549 cells and no discernible hemolytic activity. Collectively, this water-soluble galactose-decorated cationic BODIPY-based photodynamic therapy agent design provides promising insights for the development of therapy for antibiotic-resistant bacteria.

Hypoxia induces apoptosis of mouse spermatocyte GC-2 cells through activation of autophagy.

The aim of this study was to investigate the underlying mechanisms of hypoxia-induced apoptosis of GC-2spd (GC-2) cells. The GC-2 cells were treated with or without hypoxia for 12, 24, 48, and 72 h. Apoptosis of GC-2 cells was detected using TUNEL and flow cytometry. Fluorescence microscopic was used to observe the autophagy of GC-2 cells. Hypoxia-inducible factor-1alpha (HIF-1α), apoptosis-related protein and marker protein of autophagy levels were measured by Western blotting. Hypoxia induced apoptosis and autophagy of GC-2 cells, and increased expression of HIF-1α, LC3-II, Beclin-1, and pro-apoptotic protein, but reduced p62 and anti-apoptotic protein level. Meanwhile, hypoxia-induced HIF-1α mediated expression of apoptosis and autophagy-related protein in GC-2 cell. Furthermore, autophagy regulated hypoxia-induced apoptosis of GC-2 cell. Our data suggest that hypoxia induces apoptosis of GC-2 cell by activation of autophagy involving activation of the apoptosis signaling pathway under the hypoxic condition.

Rapid monitoring of plant growth regulators in bean sprouts via automated on-line polymeric monolith solid-phase extraction coupled with liquid chromatography tandem mass spectrometry.

An automated on-line solid-phase extraction (SPE) following liquid chromatography tandem mass spectrometry was established for the fast determination of plant growth regulator residues in soybean sprout and mung bean sprout. The crude extracted specimens were directly purified on a poly (2-(dimethylamino) ethyl methacrylate-co-ethylene dimethacrylate) monolithic column which was well-defined as the on-line SPE adsorbent. Under the optimized conditions, the developed method gave the linear range of 0.3-50 ng/mL for gibberellin and 2,4-dichlorophenoxyacetic acid, 0.2-50 ng/mL for 4-chlorophenoxyacetic acid, and 0.5-50 ng/mL for 1-naphthaleneacetic acid (r ≥ 0.998). The detection limits (S/N = 3) ranged from 1.0 to 2.5 µg/kg and the recoveries for spiked soybean sprout samples were in the range of 75.0-93.3%. Besides, the total time for one analysis was 16 min. The reusability of the monolith was up to 600 extractions. The proposed process facilitated fully automated SPE and accurate determination in one step with rapidity, simplicity, and reliability. Graphical abstract ᅟ.

Poly[(2-(acryloyloxy) ethyl]trimethylammonium chloride-co-ethylene dimethacrylate monolith on-line solid-phase extraction coupled with liquid chromatography and tandem mass spectrometry for the fast determination of salicylic acid in foodstuffs.

We report the fabrication of an anion-exchange monolithic column in a stainless-steel chromatographic column (10 mm × 2.1 mm i.d.) using [2-(acryloyloxy) ethyl]trimethylammonium chloride as the monomer and ethylene dimethacrylate as the crosslinker. The prepared monolith was developed as the adsorbent for the on-line solid-phase extraction of salicylic acid in various animal-origin foodstuffs combined with liquid chromatography and tandem mass spectrometry. The monolith was characterized by using Fourier transform infrared spectroscopy, scanning electron microscopy, nitrogen adsorption analysis, and elemental analysis. Potential factors affecting the on-line solid-phase extraction and liquid chromatography with tandem mass spectrometry analysis were studied in detail. Under the optimized conditions, the total analysis time including cleanup and liquid chromatography with tandem mass spectrometry separation was 17 min. The developed method gave the linear range of 15-750 µg/kg, detection limits (S/N = 3) of 5 µg/kg, and quantification limits (S/N = 10) of 15 µg/kg. The recoveries obtained by spiking 10, 20, and 100 µg/kg of salicylic acid in the animal-origin food samples were in the range of 85.2-98.4%. In addition, the monolith was stable enough for 550 extraction cycles with the precision of peak area ≤11.6%.

Testing the Axion-Conversion Hypothesis of 3.5 keV Emission with Polarization.

The recently measured 3.5 keV line in a number of galaxy clusters, the Andromeda galaxy (M31), and the Milky Way (MW) center can be well accounted for by a scenario in which dark matter decays to axionlike particles (ALPs) and subsequently convert to 3.5 keV photons in magnetic fields of galaxy clusters or galaxies. We propose to test this hypothesis by performing x-ray polarization measurements. Since ALPs can only couple to photons with a polarization orientation parallel to the magnetic field, we can confirm or reject this model by measuring the polarization of the 3.5 keV line and compare it to the orientation of the magnetic field. We discuss luminosity and polarization measurements for both a galaxy cluster and spiral galaxy, and provide a general relation between the polarization and galaxy inclination angle. This effect is marginally detectable with x-ray polarimetry detectors currently under development, such as the enhanced X-ray Timing and Polarization satellite, the Imaging X-ray Polarimetry Explorer and the X-ray Imaging Polarimetry Explorer. The sensitivity can be further improved in the future with detectors of a larger effective area or better energy resolutions.

Probing Neutrino Hierarchy and Chirality via Wakes.

The relic neutrinos are expected to acquire a bulk relative velocity with respect to the dark matter at low redshifts, and neutrino wakes are expected to develop downstream of the dark matter halos. We propose a method of measuring the neutrino mass based on this mechanism. This neutrino wake will cause a dipole distortion of the galaxy-galaxy lensing pattern. This effect could be detected by combining upcoming lensing surveys with a low redshift galaxy survey or a 21 cm intensity mapping survey, which can map the neutrino flow field. The data obtained with LSST and Euclid should enable us to make a positive detection if the three neutrino masses are quasidegenerate with each neutrino mass of ∼0.1 eV, and a future high precision 21 cm lensing survey would allow the normal hierarchy and inverted hierarchy cases to be distinguished, and even the right-handed Dirac neutrinos may be detectable.