Minimal information for studies of extracellular vesicles (MISEV2023): From basic to advanced approaches

Extracellular vesicles (EVs), through their complex cargo, can reflect the state of their cell of origin and change the functions and phenotypes of other cells. These features indicate strong biomarker and therapeutic potential and have generated broad interest, as evidenced by the steady year-on-year increase in the numbers of scientific publications about EVs. Important advances have been made in EV metrology and in understanding and applying EV biology. However, hurdles remain to realising the potential of EVs in domains ranging from basic biology to clinical applications due to challenges in EV nomenclature, separation from non-vesicular extracellular particles, characterisation and functional studies. To address the challenges and opportunities in this rapidly evolving field, the International Society for Extracellular Vesicles (ISEV) updates its 'Minimal Information for Studies of Extracellular Vesicles', which was first published in 2014 and then in 2018 as MISEV2014 and MISEV2018, respectively. The goal of the current document, MISEV2023, is to provide researchers with an updated snapshot of available approaches and their advantages and limitations for production, separation and characterisation of EVs from multiple sources, including cell culture, body fluids and solid tissues. In addition to presenting the latest state of the art in basic principles of EV research, this document also covers advanced techniques and approaches that are currently expanding the boundaries of the field. MISEV2023 also includes new sections on EV release and uptake and a brief discussion of in vivo approaches to study EVs. Compiling feedback from ISEV expert task forces and more than 1000 researchers, this document conveys the current state of EV research to facilitate robust scientific discoveries and move the field forward even more rapidly

Search for eccentric black hole coalescences during the third observing run of LIGO and Virgo

Despite the growing number of confident binary black hole coalescences observed through gravitational waves so far, the astrophysical origin of these binaries remains uncertain. Orbital eccentricity is one of the clearest tracers of binary formation channels. Identifying binary eccentricity, however, remains challenging due to the limited availability of gravitational waveforms that include effects of eccentricity. Here, we present observational results for a waveform-independent search sensitive to eccentric black hole coalescences, covering the third observing run (O3) of the LIGO and Virgo detectors. We identified no new high-significance candidates beyond those that were already identified with searches focusing on quasi-circular binaries. We determine the sensitivity of our search to high-mass (total mass M>70 M⊙) binaries covering eccentricities up to 0.3 at 15 Hz orbital frequency, and use this to compare model predictions to search results. Assuming all detections are indeed quasi-circular, for our fiducial population model, we place an upper limit for the merger rate density of high-mass binaries with eccentricities 0<e≤0.3 at 0.33 Gpc−3 yr−1 at 90\% confidence level

Ultralight vector dark matter search using data from the KAGRA O3GK run

Among the various candidates for dark matter (DM), ultralight vector DM can be probed by laser interferometric gravitational wave detectors through the measurement of oscillating length changes in the arm cavities. In this context, KAGRA has a unique feature due to differing compositions of its mirrors, enhancing the signal of vector DM in the length change in the auxiliary channels. Here we present the result of a search for U(1)B−L gauge boson DM using the KAGRA data from auxiliary length channels during the first joint observation run together with GEO600. By applying our search pipeline, which takes into account the stochastic nature of ultralight DM, upper bounds on the coupling strength between the U(1)B−L gauge boson and ordinary matter are obtained for a range of DM masses. While our constraints are less stringent than those derived from previous experiments, this study demonstrates the applicability of our method to the lower-mass vector DM search, which is made difficult in this measurement by the short observation time compared to the auto-correlation time scale of DM

Time lags of the kilohertz quasi-periodic oscillations in the low-mass X-ray binaries 4U 1608–52 and 4U 1636–53

We studied the energy and frequency dependence of the Fourier time lags and intrinsic coherence of the kilohertz quasi-periodic oscillations (kHz QPO) in the neutron-star low-mass X-ray binaries 4U 1608–52 and 4U 1636–53, using a large dataset obtained with the Rossi X-ray Timing Explorer. We confirmed that, in both sources, the time lags of the lower kHz QPO are soft (soft photons lag the hard ones) ranging from 10μs to 100μs, with the soft lags increasing with energy. Furthermore, we found that: (i) In both sources, the time lags of the upper kHz QPO are independent of energy, and inconsistent with the soft lags of the lower kHz QPOs. (ii) In 4U 1636–53, for the lower kHz QPO the 4 − 12 keV photons lag the 12 − 20 keV ones by 25μs in the QPO frequency range 500 − 850 Hz, with the soft lags decreasing to 15μs when the QPO frequency increases further. In 4U 1608–52 the soft lags of the lower kHz QPO remain constant at 40μs up to 800 Hz, the highest frequency reached by this QPO in our data. (iii) In 4U 1636–53, the time lags of the upper kHz QPO are hard (the 12 − 20 keV photons lag the 4 − 12 keV ones), at 11 ± 3μs, independent of QPO frequency (from 500 Hz to 1200 Hz). We found consistent results for the time lags of the upper kHz QPO in 4U 1608–52, albeit with larger error bars than in 4U 1636–53 over the narrower frequency interval covered by the upper kHz QPO in our data (880 − 1040 Hz). (iv) In both sources the intrinsic coherence (4 − 12 keV vs. 12 − 20 keV) of the lower kHz QPO remains constant at 0.6 between 5 and 12 keV, and drops to zero above that energy. The intrinsic coherence of the upper kHz QPO is consistent with being zero across the full energy range. (v) The intrinsic coherence of the lower kHz QPO increases from 0 − 0.4 at 600 Hz to 1 and 0.6 at 800 Hz in 4U 1636–53 and 4U 1608–52, respectively. In 4U 1636–53 the intrinsic coherence decreases to 0.5 at 920 Hz, while in 4U 1608–52 we do not have data above 800 Hz. (vi) In both sources the intrinsic coherence of the upper kHz QPO is consistent with zero over the full frequency range of the QPO, except in 4U 1636–53 between 700 Hz and 900 Hz where the intrinsic coherence marginally increases, reaching a value 0.13 at 780 Hz. We discuss our results in the context of scenarios in which the soft lags are either due to reflection off the accretion disc or up-/down-scattering in a hot medium close to the neutron star. We finally explore the connection between, on one hand the time lags and the intrinsic coherence of the kHz QPOs, and on the other the QPOs’ amplitude and quality factor in these two sources. Key words: stars: neutron – X-rays: binaries – X-rays: individual: 4U 1608–52 – X-rays: individual: 4U 1636–53 ⋆ m