Time-resolved Analysis Research Articles

Photophysical properties of Radachlorin photosensitizer in solutions of different pH, viscosity and polarity

We present a thorough experimental investigation of fluorescence properties of Radachlorin photosensitizer in solutions of different acidity, viscosity and polarity. Experiments were performed using time-resolved fluorescence lifetime imaging and time-resolved analysis of polarized fluorescence. Variations of solution acidity resulted in considerable changes of Radachlorin fluorescence quantum yield and lifetime in the pH range from 4 to 7, but did not affect the rotational diffusion time, and almost did not change the quantum yield and characteristic times of singlet oxygen phosphorescence. Variations of solution polarity and viscosity were achieved by changing ethanol or methanol fraction in aqueous solution. The decrease of solution polarity resulted in nonlinear rise of Radachlorin fluorescence quantum yield and lifetime up to alcohol concentration of 50%–65%, as well as in considerable rise of singlet oxygen quantum yield and significant changes in characteristic times of its phosphorescence. Variations of solution viscosity resulted in changes of rotational diffusion time of Radachlorin molecules, which appeared to be in perfect correlation with methanol solution viscosity. Good correspondence with ethanol solution viscosity was observed only up to 50% alcohol fraction. Deviations of rotational diffusion time of Radachlorin molecules from direct proportionality with solution viscosity at higher ethanol concentrations were suggested to be due to different solvation conditions. The data obtained can give important reference points for analysis of microenvironment of Radachlorin molecules, their intracellular localization and performance in singlet oxygen generation.

Time-resolved photoluminescence analysis of ceramic Ce:GAGG scintillators.

This paper introduces the characteristics and efficiency of post-treatment methods for enhancing the timing resolution of ceramic Ce:GAGG scintillators. The thermal annealing and surface treatments were included to analyze their impact on time-resolved photoluminescence (TRPL) and thermoluminescence (TL) characteristics. Optical properties were improved by suppressing nonradiative recombination due to the reduced surface defects, while heat-treatment removes traps as confirmed by TL measurements. TRPL decay characteristics revealed that samples treated with mechanical polishing followed by heat treatment exhibited the best scintillation performance, with a slow component of 272.3 ns. These findings will aid in developing techniques for improving the luminescence of other inorganic scintillators.

AGILE Gamma-Ray Detection of the Exceptional GRB 221009A

Gamma-ray emission in the MeV–GeV range from explosive cosmic events is of invaluable relevance to understanding physical processes related to the formation of neutron stars and black holes. Here we report on the detection by the AGILE satellite in the MeV–GeV energy range of the remarkable long-duration gamma-ray burst GRB 221009A. The AGILE onboard detectors have good exposure to GRB 221009A during its initial crucial phases. Hard X-ray/MeV emission in the prompt phase lasted hundreds of seconds, with the brightest radiation being emitted between 200 and 300 s after the initial trigger. Very intense GeV gamma-ray emission is detected by AGILE in the prompt and early afterglow phase up to 10,000 s. Time-resolved spectral analysis shows time-variable MeV-peaked emission simultaneous with intense power-law GeV radiation that persists in the afterglow phase. The coexistence during the prompt phase of very intense MeV emission together with highly nonthermal and hardening GeV radiation is a remarkable feature of GRB 221009A. During the prompt phase, the event shows spectrally different MeV and GeV emissions that are most likely generated by physical mechanisms occurring in different locations. AGILE observations provide crucial flux and spectral gamma-ray information regarding the early phases of GRB 221009A during which emission in the TeV range was reported.

Multidimensional stimulation response RTP micron fiber thin film

Purpose The purpose of this research is as follows: DPP-BOH-PVA has been synthesized from 1,1′:3′,1″-terphenyl-5'-boronic acid (DPP-OH) and polyvinyl alcohol (PVA). The afterglow lifetime of DPP-BOH-PVA was studied by changing contents of DPP-OH (1, 2 and 4 Wt.%). These films were characterized with Fourier transform infrared, X-ray diffraction as structural analysis and DSC as thermal analysis. Afterglow lifetimes were evaluated as time-resolved emission decay profile analysis. Fiber films of DPP-BOH-PVA-2-E have been prepared by electrospinning method with the diameter of 5 μm and afterglow life time of 2.1 s (@ 535 nm) under ambient conditions. Stimulus responsive properties with afterglow emission for fiber film were investigated. Design/methodology/approach During the synthesis of the polymer, modification was carried out using DPP-OH/PVA with a molar ratio of 1/4, under an alkalinity medium with ammonium hydroxide and with a temperature of 80°C. Findings XRD results indicate that DPP-BOH-PVA film had high crystallinity, which is crucial for preparing organic room temperature phosphorescence (RTP) materials. Research limitations/implications The reaction mixture must be stirred continuously. Temperature should be controlled to prevent the rapid evaporation of ammonium hydroxide. Practical implications This study provides technical information for the synthesis of multidimensional stimulation response RTP micron fiber thin film. The electrospinning technology may also promote the applications of the large areas of RTP films. Social implications This resin will be used for the multidimensional stimulation response RTP fiber thin film. Originality/value The diameter of fiber film of PP-BOH-PVA-2-E by electrospinning method was in the range of 5 μm, and its afterglow lifetime decayed to be 2.1 s.

Interaction mechanism of pea proteins with selected pyrazine flavors: Differences in alkyl numbers and flavor concentration

The mechanism of pea protein (PPI) adsorbing flavor components of cooked beef (pyrazine flavor compounds with different concentrations and different numbers of alkyl groups) was researched by spectroscopic and molecular docking approaches. The binding ability results showed that the concentration of pyrazines and the number of alkyl groups in pyrazine strongly influenced the adsorbing ability of PPI. The binding ability of PPI to the pyrazines decreased in the order 2,3,5-trimethyl-pyrazine (TRP) > 2,5-dimethyl pyrazine (DP) > 2-methylpyrazine (MP). The increase in the concentration of pyrazine flavor compounds promoted the enhancement of the adsorption capacity of PPI. Fluorescence and time-resolved fluorescence analysis showed that different molecular structures caused by the amount of alkyl groups on a pyrazine ring showed different quenching types: MP and DP were mainly subjected to static quenching, and TRP with more alkyl groups was mainly subjected to dynamic quenching. During the adsorption of pyrazine flavor compounds, the structure on the peptide bond of pea protein is destroyed. The conformation of pea protein expanded gradually, and the protein changed from ordered structure to disordered structure with lower ΔH. The interactions between pyrazine and pea protein were spontaneous from thermodynamic analysis. Combined with the results of molecular docking, hydrophobic interactions were dominant in the noncovalent interactions between MP and pea protein, whereas hydrogen bonding was dominant between DP/TRP and pea protein. TRP with more alkyl groups could generate new interactions with PPI (π-π stacking interaction) to improve the adsorption capacity of PPI. Pyrazine with more alkyl groups showed a stronger binding force with pea protein to improve the ability of pea protein to adsorb pyrazine flavor compounds, and they displayed different fluorescence quenching mechanisms. This study could provide a theoretical basis for flavor selection and control in the production of pea protein-based meat analogs and thus improve the overall flavor of plant protein-based meat analog products.

Spectral analysis of the LMXB XTE J1810−189 with NICER data

ABSTRACT X-ray Timing Explorer J1810−189 is a low-mass X-ray binary transient system hosting a neutron star, which underwent a three-month-long outburst in 2020. In order to study its spectral evolution during this outburst, we analysed all the available observations performed by Neutron star Interior Composition Explorer, in the 1–10 keV energy band. First, we fitted the spectra with a thermal Comptonization model. Our analysis revealed the lack of a significant direct emission from a blackbody-like component, therefore we calculated the optical depth of the Comptonizing region, deriving an upper limit of 4.5, which suggests the presence of a moderately thick corona. We also attempted to fit the spectrum with an alternative model, i.e. a cold Comptonized emission from a disc and a direct thermal component from the neutron star, finding a similarly good fit. The source did not enter a full high luminosity/soft state throughout the outburst, with a photon index ranging from ∼1.7 to ∼2.2, and an average unabsorbed flux in the 1–10 keV band of ∼3.6 × 10−10 erg cm−2 s−1. We searched for the presence of Fe K-shell emission lines in the range ∼6.4–7 keV, significantly detecting a broad component only in a couple of observations. Finally, we conducted a time-resolved spectral analysis of the detected type-I X-ray burst, observed during the outburst, finding no evidence of a photospheric radius expansion. The type-I burst duration suggests a mix of H/He fuel.

Single-cell analysis of bovine muscle-derived cell types for cultured meat production.

Cultured meat technologies leverage the proliferation and differentiation of animal-derived stem cells ex vivo to produce edible tissues for human consumption in a sustainable fashion. However, skeletal muscle is a dynamic and highly complex tissue, involving the interplay of numerous mono- and multinucleated cells, including muscle fibers, satellite cells (SCs) and fibro-adipogenic progenitors (FAPs), and recreation of the tissue in vitro thus requires the characterization and manipulation of a broad range of cell types. Here, we use a single-cell RNA sequencing approach to characterize cellular heterogeneity within bovine muscle and muscle-derived cell cultures over time. Using this data, we identify numerous distinct cell types, and develop robust protocols for the easy purification and proliferation of several of these populations. We note overgrowth of undesirable cell types within heterogeneous proliferative cultures as a barrier to efficient cultured meat production, and use transcriptomics to identify conditions that favor the growth of SCs in the context of serum-free medium. Combining RNA velocities computed in silico with time-resolved flow cytometric analysis, we characterize dynamic subpopulations and transitions between active, quiescent, and committed states of SCs, and demonstrate methods for modulation of these states during long-term proliferative cultures. This work provides an important reference for advancing our knowledge of bovine skeletal muscle biology, and its application in the development of cultured meat technologies.

DELLA-mediated gene repression is maintained by chromatin modification in rice.

DELLA proteins are master regulators of gibberellic acid (GA) signaling through their effects on gene expression. Enhanced DELLA accumulation in rice and wheat varieties has greatly contributed to grain yield increases during the green revolution. However, the molecular basis of DELLA-mediated gene repression remains elusive. In this work, we show that the rice DELLA protein SLENDER RICE1 (SLR1) forms a tripartite complex with Polycomb-repressive complex 2 (PRC2) and the histone deacetylase HDA702 to repress downstream genes by establishing a silent chromatin state. The slr1 mutation and GA signaling resulted in dissociation of PRC2 and HDA702 from GA-inducible genes. Loss-of-function or downregulation of the chromatin regulators impaired SLR1-dependent histone modification and gene repression. Time-resolved analysis of GA signaling revealed that GA-induced transcriptional activation was associated with a rapid increase of H3K9ac followed by H3K27me3 removal. Collectively, these results establish a general epigenetic mechanism for DELLA-mediated gene repression and reveal details of the chromatin dynamics during transcriptional activation stimulated by GA signaling.

Influence of the W and Ta content on the High-Temperature Oxidation Resistance of Multinary Co/Ni-Based Superalloys at 1050 °C and 1150 °C

Outstanding inherent environmental resistance is a precondition for the use of superalloys in high-temperature applications. Besides high Al and Cr levels, also refractory metal concentrations (W and Ta) are reported to affect protective scale formation, as these elements are expected to affect the chemical activity and also the transport of protective scale formers within the alloy. In this study, we elucidate the high-temperature oxidation behavior of 3 Co-based (Co/Ni ratio: 1.4) and 3 Ni-based (Co/Ni ratio: 0.7) superalloys differing in W and Ta levels. Time-resolved thermogravimetric analysis (TGA) in synthetic air at 1050 °C and 1150 °C for 100 h, scanning electron microscopy analysis (SEM), thermodynamic calculations using the CALPHAD software Thermo-Calc, and diffusion couple experiments were conducted to assess the impact of the Co/Ni ratio and the refractory metal content on the oxidation performance. The results indicate that a low W content (3 vs. 5 at.%) and a high Ta content (2.1 vs. 1.5 at.%) beneficially affect the oxidation resistance, as alumina scale formation is facilitated.

Discovery of a Variable Multiphase Outflow in the X-Ray-emitting Tidal Disruption Event ASASSN-20qc

Tidal disruption events (TDEs) are exotic transients that can lead to temporary super-Eddington accretion onto a supermassive black hole. Such an accretion mode is naturally expected to result in powerful outflows of ionized matter. However, to date such an outflow has only been directly detected in the X-ray band in a single TDE, ASASSN-14li. This outflow has a low velocity of just a few 100 km s−1, although there is also evidence for a second, ultrafast phase. Here we present the detection of a low-velocity outflow in a second TDE, ASASSN-20qc. The high-resolution X-ray spectrum reveals an array of narrow absorption lines, each blueshifted by a few 100 km s−1, which cannot be described by a single photoionization phase. For the first time, we confirm the multiphase nature of a TDE outflow, with at least two phases and two distinct velocity components. One highly ionized phase is outflowing at km s−1, while a lower ionization component is blueshifted by km s−1. We perform a time-resolved analysis of the X-ray spectrum and detect that, surprisingly, the ionization parameter of the mildly ionized absorber strongly varies over the course of a single 60 ks observation, indicating that its distance from the black hole may be as low as 400 gravitational radii. We discuss these findings in the context of TDEs and compare this newly detected outflow with that of ASASSN-14li.

High‐Capacity and Stable Sodium‐Sulfur Battery Enabled by Novel Molybdenum Carbide Electrocatalyst and Carbon Nanoporosity

Room-temperature sodium - sulfur (RT Na-S) batteries are highly promising due to the favorable techno-economics and the greater availability of both sodium and sulfur. RT Na-S cells are held back by several primary challenges including dissolution of polysulfides species in liquid electrolytes, sluggish sulfur redox kinetics, as well as the large cathode volume expansion (170%) on cell discharge. Here, we develop a novel molybdenum carbide (MoC/Mo2C) electrocatalyst to promote Na-S reaction kinetics and extend batteries’ cycling lifetime. MoC/Mo2C nanoparticles is in-situ grown in conjunction with activation of nitrogen-doped hollow porous carbon nanotubes. Sulfur impregnation (50wt.% S) results in unique triphasic architecture termed MoC/Mo2C@PCNT-S. MoC/Mo2C electrocatalyst and carbon nanoporosity synergistically promote the sulfur utilization in carbonate electrolyte. In-situ time-resolved Raman, XPS and optical analysis demonstrate a quasi-solid-state phase transformation within MoC/Mo2C@PCNT-S, where minimal polysulfides are dissolved in electrolyte. As results, MoC/Mo2C@PCNT-S cathodes performed promising rate performance of 987 mAh g-1 at 1 A g-1, 818 mAh g-1 at 3 A g-1, and 621 mAh g-1 at 5 A g-1. The cells delivered a retained capacity of 650 mAh g-1 after 1000 cycles at 1.5 A g-1, which corresponds to only 0.028% capacity decay per cycle. Such promising cycling stability is also obtained for high mass loading cathodes (64wt.% S, 12.7 mg cm-2). Complementary Density Functional Theory (DFT) simulation provide fundamental insight regarding the electrocatalytic role of MoC/Mo2C nanoparticles. Favorable charge transfer between the sulfur and Mo sites on the surface of carbides contributes to a strong binding of Na2Sx (1 ≤ x ≤ 4) on MoC/Mo2C surfaces. Consequently, the formation energy of Na2Sx (1 ≤ x ≤ 4) on MoC/Mo2C is significantly lowered compared to the analogous redox in liquid, as well as the case of baseline ordered carbon.

Au@SnO2 Core@Shell Nanocrystals for Sustainable Environmental Purifications

The search for versatile catalysts for sustainable environmental purifications has been a challenging yet very important research topic especially in the post pandemic era. Core@shell nanocrystals composed of metal core and semiconductor shell have received significant attention as both photocatalysts and chemical catalysts for practical use in organic dyes degradation and bacterial disinfection. This work reports the synthesis of Au@SnO2 core@shell nanocrystals with controllable shell thicknesses. Under light illumination, Au@SnO2 can function as photocatalysts to decompose organic dyes (rhodamine B, RhB) and inactivate E. coli. Because of the band alignment between Au and SnO2, an enhanced photocatalytic activity was achieved on Au@SnO2. Time-resolved photoluminescence spectroscopic analysis was conducted to explore the influence of shell thickness on the interfacial charge dynamics of Au@SnO2 in order to establish the correlation with the resultant photocatalytic performance. On the other hand, the peroxidase mimics features of Au and SnO2 endowed Au@SnO2 with the capability of performing the disinfection of E. coli under darkness conditions. By combining the phtotocatalytic capacity with the peroxidase mimics features, Au@SnO2 demonstrated sustainable activity toward E. coli disinfection under both irradiation and darkness conditions.

Time-Resolved Structural Analysis of Fast-Photoresponsive Surfactant Micelles by Stroboscopic Small-Angle Neutron Scattering.

Photoresponsive materials are garnering attention because of their applications toward building a sustainable society. A recently developed fast-photoresponsive amphiphilic lophine dimer (3TEG-LPD) responds rapidly to light, making it a promising candidate for drug-delivery systems. In this study, the mechanism of structural changes induced by ultraviolet (UV) irradiation in 3TEG-LPD micelles in an aqueous solution was investigated via an in situ time-resolved small-angle neutron scattering (SANS) technique. Since subsecond resolution was necessary to observe the structural changes in the 3TEG-LPD micelles, stroboscopic SANS analysis was employed to obtain scattering profiles with a time width of 0.5 s. The structural parameters were quantitatively determined by performing a model-fitting analysis of the SANS results. The stroboscopic SANS results showed that upon UV irradiation, the axial ratio and pseudo-aggregation number of the 3TEG-LPD micelles increased by 1.8 and 1.6 times, respectively, whereas the number of water molecules per surfactant molecule decreased. This finding suggested that the change in the shape of the micelles from spherical to ellipsoidal shape was accompanied by dehydration. Under the present UV irradiation conditions, this structural change of the micelle occurred rapidly during the first 30 s after the start of UV irradiation. Each structural parameter recovered exponentially and reversibly during the recovery process after the cessation of UV irradiation. The changes in these parameters were analyzed in terms of kinetics by comparing them with the changes in the molecular structure. We found that the change of the micelles proceeds approximately twice as fast as the association of the molecule. Furthermore, from the perspective of the critical packing parameter consideration, the SANS analysis revealed that the UV-induced changes in 3TEG-LPD micelles are dominated by the enthalpy contribution. This finding is expected to be useful for developing new materials for various applications.

Time-resolved quantitative proteomic analysis of the developing Xenopus otic vesicle reveals putative congenital hearing loss candidates

Over 200 genes are known to underlie human congenital hearing loss (CHL). Although transcriptomic approaches have identified candidate regulators of otic development, little is known about the abundance of their protein products. We used a multiplexed quantitative mass spectrometry-based proteomic approach to determine protein abundances over key stages of Xenopus otic morphogenesis to reveal a dynamic expression of cytoskeletal, integrin signaling, and extracellular matrix proteins. We correlated these dynamically expressed proteins to previously published lists of putative downstream targets of human syndromic hearing loss genes: SIX1 (BOR syndrome), CHD7 (CHARGE syndrome), and SOX10 (Waardenburg syndrome). We identified transforming growth factor beta-induced (Tgfbi), an extracellular integrin-interacting protein, as a putative target of Six1 that is required for normal otic vesicle formation. Our findings demonstrate the application of this Xenopus dataset to understanding the dynamic regulation of proteins during otic development and to discovery of additional candidates for human CHL.

Single-Sided Nuclear Magnetic Resonance (NMR) for the Analysis of Skin Thickness and Collagen Structure in Scarred and Healthy Skin

Monitoring of skin scar thickness and structural properties is desirable when assessing the efficacy of the healing process. In this work, we report the use of single-sided, low-field nuclear magnetic resonance (NMR) for the analysis of the thickness and collagen structure of healthy and scarred skin. Acquisition of T2 relaxation profiles was proven to provide quantification of porcine skin thickness as accurate as standard histological techniques. Subsequent analysis of human participants highlighted the utility of this technique for identifying different types of scar and in identifying differences between the thickness of moderate hypertrophic scars and healthy skin. Using bead packings as a model system, determination of the surface-to-volume (S/V) ratio and tortuosity (k) was successfully measured on the single-sided apparatus based on time-resolved diffusion analysis. Application of this method to human skin was able to detect regional differences in collagen structures, consistent with qualitative expectations. It was also able to differentiate between healthy and scarred skin tissue. Preliminary results indicated that scarred tissue exhibited decreased S/V ratios and tortuosities, which is coherent with the formation of less-aligned collagen within scar tissue and indicated the potential for this technique to differentiate scar types. This novel application of single-sided low-field NMR has the potential to be deployed in clinical settings for the differentiation of scar types and for the assessment and monitoring of skin scarring and healing.

Inference-based time-resolved stability analysis of nonlinear whole-cortex modeling: application to Xenon anaesthesia.

This study characterizes the neurophysiological mechanisms underlying electromagnetic imaging signals using stability analysis. Researchers have proposed that transitions between conscious awake and anaesthetised states, and other brain states more generally, may result from system stability changes. The concept of stability in dynamical systems theory provides a mathematical framework to describe this possibility. In particular, the degree to which a system's trajectory in phase space is affected by small perturbations determines the stability. Previous studies using linear or oscillator-based whole-brain models cannot represent complex cerebrocortical dynamics, or model parameters were pre-assumed or inferred from data but did not change over time. This study proposes a nonlinear neurophysiologically plausible whole-cortex modeling framework to analyze the stability of brain dynamics for the emergence and disappearance of consciousness using time-varying parameters estimated from the data.Clinical relevance- Depth of anaesthesia is typically measured through changes in EEG statistics like the bispectral index and spectral entropy. However, these monitors have been found to fail in preventing awareness during surgery and postoperative recall. Our whole-cortex stability analysis may be useful in measuring anaesthesia levels in clinical settings, as it changes with the level of consciousness and is independent of individual differences and anaesthetic agents. The proposed method can also be used to, for example, identify critical brain regions for consciousness, locate the epileptogenic zone and investigate the dominance of extrinsic or intrinsic factors in brain functions.

Selective Analysis of Redox Processes at the Electrode Interface with Time-Resolved Raman Spectroscopy.

Electrochemistry and electrochemical reactions are increasingly important in the transition to a sustainable chemical industry. The electron transfer that drives such reactions takes place within nanometers of the electrode surface, and follow-up chemical reactions take place within the diffusion layer. Hence, understanding electrochemical reactions requires time-, potential-, and spatially resolved analysis. The confocal nature of Raman spectroscopy provides high spatial resolution, in addition to detailed information on molecular structure. The intrinsic weakness of nonresonant Raman scattering, however, is not sensitive enough for relatively minor changes to the solution resulting from reactions at the electrode interface. Indeed, the limit of detection is typically well above the concentrations used in electrochemical studies. Here, we show that surface-enhanced Raman scattering (SERS) and resonance Raman (rR) spectroscopy allow for spatially and time-resolved analysis of solution composition at (<1-2 nm) and near (within 5 μm) the electrode surface, respectively, in a selective manner for species present at low (<1 mM) concentrations. We show changes in concentration of species at the electrode surface, without the need for labels, specific adsorption, or resonance enhancement, using a SERS-active gold electrode prepared readily by electrochemical surface roughening. A combination of smooth and roughened gold electrodes is used to distinguish between surface and resonance enhancement using the well-known redox couples ferrocene and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS). We discuss the impact of specific adsorption on the spectral analysis with the ruthenium(II) polypyridyl complex, [Ru(bpy)3]2+. The dual function of the electrode (surface enhancement and electron transfer) in the analysis of solution processes is demonstrated with the reversible oxidation of TMA (4,N,N-trimethylaniline), where transient soluble species are identified in real time, with rapid spectral acquisition, making use of localized enhancement. We anticipate that this approach will find use in elucidating electro(catalytic) reactions at electrode interfaces.

67-kDa laminin receptor mediates oolonghomobisflavan B-induced cell growth inhibition in melanoma

BackgroundOolonghomobisflavans are unique polyphenols found in oolong teas. Oolonghomobisflavan B (OHBFB), a dimer of (–)-epigallocatechin-3-O-gallate (EGCG), is an active compound found in green tea. PurposeOHBFB has been reported to exert an inhibitory effect on lipase enzyme activity. However, little is known regarding its intercellular signaling induction effect. Further, there are no reports describing the anti-cancer effects of OHBFB. MethodsThe effect of OFBFB on B16 melanoma cells was evaluated by cell counting, and its mechanisms were determined by western blot analysis with or without protein phosphatase 2A (PP2A) inhibitor treatment. Intracellular cyclic adenosine monophosphate (cAMP) levels were evaluated by time-resolved fluorescence resonance energy transfer analysis. Quartz crystal microbalance (QCM) analysis was performed to assess the binding of OHBFB to 67LR. ResultsCell growth assay and western blot analyses showed that OHBFB inhibited melanoma cell growth, followed by myosin phosphatase target subunit 1 (MYPT1) and myosin regulatory light chain (MRLC) dephosphorylation via protein phosphatase 2A (PP2A)-dependent mechanisms. These effects are mediated by intracellular cAMP- and protein kinase A (PKA) A-dependent mechanisms. QCM analysis identified the 67-kDa laminin receptor (67LR) as an OHBFB receptor with a Kd of 3.7 µM. We also demonstrated for the first time that OHBFB intake suppresses tumor growth in vivo. ConclusionsTaken together, these results indicate that the cAMP/PKA/PP2A/MYPT1/MRLC pathway is a key mediator of melanoma cell growth inhibition following OHBFB binding to 67LR and that OHBFB suppresses tumor growth in vivo.

Time-resolved molecular measurements reveal changes in astronauts during spaceflight.

From the early days of spaceflight to current missions, astronauts continue to be exposed to multiple hazards that affect human health, including low gravity, high radiation, isolation during long-duration missions, a closed environment and distance from Earth. Their effects can lead to adverse physiological changes and necessitate countermeasure development and/or longitudinal monitoring. A time-resolved analysis of biological signals can detect and better characterize potential adverse events during spaceflight, ideally preventing them and maintaining astronauts' wellness. Here we provide a time-resolved assessment of the impact of spaceflight on multiple astronauts (n = 27) by studying multiple biochemical and immune measurements before, during, and after long-duration orbital spaceflight. We reveal space-associated changes of astronauts' physiology on both the individual level and across astronauts, including associations with bone resorption and kidney function, as well as immune-system dysregulation.

Time-resolved burst variance analysis

Quantifying biomolecular dynamics has become a major task of single-molecule fluorescence spectroscopy methods. In single-molecule Förster resonance energy transfer (smFRET), kinetic information is extracted from the stream of photons emitted by attached donor and acceptor fluorophores. Here, we describe a time-resolved version of burst variance analysis that can quantify kinetic rates at microsecond to millisecond timescales in smFRET experiments of diffusing molecules. Bursts are partitioned into segments with a fixed number of photons. The FRET variance is computed from these segments and compared with the variance expected from shot noise. By systematically varying the segment size, dynamics at different timescales can be captured. We provide a theoretical framework to extract kinetic rates from the decay of the FRET variance with increasing segment size. Compared to other methods such as filtered fluorescence correlation spectroscopy, recurrence analysis of single particles, and two-dimensional lifetime correlation spectroscopy, fewer photons are needed to obtain reliable timescale estimates, which reduces the required measurement time.