Flare Events Research Articles

Examining Solar Flare Effects on Earth's Ionosphere Using Ground-Based Measurements

This study investigated the simultaneous effects of solar flares (SFs) on both the D and E layers of Earth's ionosphere. The analysis focused on the M and X-class SFs that occurred during the 24th solar cycle as these two classes of SFs are known to produce significant effects on Earth’s environment, particularly during the daytime period. The data utilized to detect the SF events in this study were ground-based magnetometer data from the equatorial regions. Effects of the selected SF events on the E layer were investigated based on the EUEL index constructed using the geomagnetic data. Meanwhile, the changes in the strength of radio VLF signals in the D ionospheric layer during the selected SF events were monitored using Sudden Ionospheric Disturbance (SID) data. Two case studies were performed which consisted of four SF events from a total of 23 events that were detected by geomagnetic data during the period of study. Further analysis on the selected SF events showed the common effects of SFs on the D layer, which is the increment on the VLF signal measured from the SID stations although a different response was detected in the EUEL index variations. This indicates that the VLF signal always shows an increment even though a decrement in the ionization of the E layer occurs as a result of the SF events. The difference in responses could be attributed to the distinct changes in electron density of both layers during the SF occurrence. Further studies are needed to elucidate the underlying mechanism responsible for this unique response, utilizing appropriate parameters such as total electron content, as well as the electron density data to thoroughly analyze the ionospheric response during SF events.

Formation of an observed eruptive flux rope above the torus instability threshold through tether-cutting magnetic reconnection

Context. Erupting magnetic flux ropes (MFRs) are believed to play a crucial role in producing solar flares. However, the formation of erupting MFRs in complex coronal magnetic configurations and the role of their subsequent evolution in the flaring events are not fully understood. Aims. We perform a magnetohydrodynamic (MHD) simulation of active region NOAA 12241 to understand the formation of a rising magnetic flux rope during the onset of an M6.9 flare on 2014 December 18 around 21:41 UT (SOL2014-12- 18T21:41M6.9), which was followed by the appearance of parallel flare ribbons. Methods. The MHD simulation was initialised with an extrapolated non-force-free magnetic field generated from the photospheric vector magnetogram of the active region taken a few minutes before the flare. Results. The initial magnetic field topology displays a pre-existing sheared arcade enveloping the polarity inversion line. The simulated dynamics exhibit the movement of the oppositely directed legs of the sheared arcade field lines towards each other due to the converging Lorentz force, resulting in the onset of tether-cutting magnetic reconnection that produces an underlying flare arcade and flare ribbons. Concurrently, a magnetic flux rope above the flare arcade develops inside the sheared arcade and shows a rising motion. The flux rope is found to be formed in a torus-unstable region, thereby explaining its eruptive nature. Interestingly, the location and rise of the rope are in good agreement with the corresponding observations seen in extreme-ultraviolet channels of the Atmospheric Imaging Assembly (AIA) of the Solar Dynamics Observatory (SDO). Furthermore, the foot points of the simulation’s flare arcade match well with the location of the observed parallel ribbons of the flare. Conclusions. The presented simulation supports the development of the MFR by the tether-cutting magnetic reconnection inside the sheared coronal arcade during flare onset. The MFR is then found to extend along the polarity inversion line (PIL) through slip-running reconnection. The MFR’s eruptive nature is ascribed both to its formation in the torus-unstable region and also to the runaway tether-cutting reconnection.

Operational prediction of solar flares using a transformer-based framework

Solar flares are explosions on the Sun. They happen when energy stored in magnetic fields around solar active regions (ARs) is suddenly released. Solar flares and accompanied coronal mass ejections are sources of space weather, which negatively affects a variety of technologies at or near Earth, ranging from blocking high-frequency radio waves used for radio communication to degrading power grid operations. Monitoring and providing early and accurate prediction of solar flares is therefore crucial for preparedness and disaster risk management. In this article, we present a transformer-based framework, named SolarFlareNet, for predicting whether an AR would produce a gamma-class flare within the next 24 to 72 h. We consider three gamma classes, namely the geM5.0 class, the geM class and the geC class, and build three transformers separately, each corresponding to a gamma class. Each transformer is used to make predictions of its corresponding gamma-class flares. The crux of our approach is to model data samples in an AR as time series and to use transformers to capture the temporal dynamics of the data samples. Each data sample consists of magnetic parameters taken from Space-weather HMI Active Region Patches (SHARP) and related data products. We survey flare events that occurred from May 2010 to December 2022 using the Geostationary Operational Environmental Satellite X-ray flare catalogs provided by the National Centers for Environmental Information (NCEI), and build a database of flares with identified ARs in the NCEI flare catalogs. This flare database is used to construct labels of the data samples suitable for machine learning. We further extend the deterministic approach to a calibration-based probabilistic forecasting method. The SolarFlareNet system is fully operational and is capable of making near real-time predictions of solar flares on the Web.

Early Planet Formation in Embedded Disks (eDisk). VII. Keplerian Disk, Disk Substructure, and Accretion Streamers in the Class 0 Protostar IRAS 16544–1604 in CB 68

We present observations of the Class 0 protostar IRAS 16544–1604 in CB 68 from the “Early Planet Formation in Embedded Disks (eDisk)” ALMA Large program. The ALMA observations target continuum and lines at 1.3 mm with an angular resolution of ∼5 au. The continuum image reveals a dusty protostellar disk with a radius of ∼30 au seen close to edge-on and asymmetric structures along both the major and minor axes. While the asymmetry along the minor axis can be interpreted as the effect of the dust flaring, the asymmetry along the major axis comes from a real nonaxisymmetric structure. The C18O image cubes clearly show the gas in the disk that follows a Keplerian rotation pattern around a ∼0.14 M ⊙ central protostar. Furthermore, there are ∼1500 au scale streamer-like features of gas connecting from northeast, north–northwest, and northwest to the disk, as well as the bending outflow as seen in the 12CO (2–1) emission. At the apparent landing point of the NE streamer, there is SO (65–54) and SiO (5–4) emission detected. The spatial and velocity structure of the NE streamer can be interpreted as a free-falling gas with a conserved specific angular momentum, and the detection of the SO and SiO emission at the tip of the streamer implies the presence of accretion shocks. Our eDisk observations have unveiled that the Class 0 protostar in CB 68 has a Keplerian-rotating disk with a flaring and nonaxisymmetric structure associated with accretion streamers and outflows.

Big flares from small stars: detecting flares from faint low-mass stars with NGTS full-frame images

ABSTRACT High-cadence observations of high-energy stellar flares from cool and ultracool dwarfs are often limited by the faint nature of their host stars. Many low-mass sources cannot be detected in quiescence by photometric surveys, meaning they are not targeted for high-cadence observations. This reduces the chances of detecting the rarest high-energy flare events. We used the 13-s cadence full-frame images of Next-Generation Transit Survey (NGTS) to search for flares from M and L dwarfs. This included stars that were too faint to detect in quiescence. We detect 160 flares from 135 stars, with spectral types ranging from M3 to L2.5. We use our sample to study the energies, amplitudes and durations of flares from M and L dwarfs. We measure bolometric flare energies up to 4.5 × 1034 erg for ultracool dwarfs, but conclude that we have not reached a maximum limit to the energy released during white-light flares. We use our results to study the incidence rate of flares of mid- and late-M stars, not accounting for age or binarity, and find that 1.4 ± 0.4 and $9^{+16}_{-3}$ per cent of mid- and late-M stars, respectively, exhibit flares with amplitudes above 1 mag in the NGTS bandpass. Future studies with greater numbers of NGTS fields will expand upon this work.

Exploring the short-term variability of H α and H β emissions in a sample of M dwarfs

ABSTRACT The time-scales of variability in active M dwarfs can be related to their various physical parameters. Thus, it is important to understand such variability to decipher the physics of these objects. In this study, we have performed the low resolution (∼5.7 Å) spectroscopic monitoring of 83 M dwarfs (M0–M6.5) to study the variability of H α/H β emissions; over the time-scales from ∼0.7 to 2.3 h with a cadence of ∼3–10 min. Data of a sample of another 43 late-type M dwarfs (M3.5–M8.5) from the literature are also included to explore the entire spectral sequence. 53 of the objects in our sample (∼64 per cent) show statistically significant short-term variability in H α. We show that this variability in 38 of them are most likely to be related to the flaring events. We find that the early M dwarfs are less variable despite showing higher activity strengths (LH α/Lbol and LH β/Lbol), which saturates around ∼10−3.8 for M0–M4 types. Using archival photometric light curves from TESS and Kepler/K2 missions, the derived chromospheric emission (H α and H β emission) variability is then explored for any plausible systematics with respect to their rotation phase. The variability indicators clearly show higher variability in late-type M dwarfs (M5–M8.5) with shorter rotation periods (<2 d). For 44 sources, their age has been estimated using StarHorse project and possible correlations with variability have been explored. The possible causes and implications for these behaviours are discussed.

Low latitude ionospheric TEC response to the solar flares during the peak of solar cycle 24

We describe the newly discovered response of differential vertical total electron content (DVTEC) in the low-equatorial latitude ionosphere to the solar flares during the peak of solar cycle 24 i.e., the year 2014. GPS TEC data for the existing investigation has been acquired from the international GNSS services network station in Bangalore, India (geomagnetic latitude 4.58οN). For the year 2014, we inspected five X-class solar flares, forty-nine M-class solar flares, and three hundred ninety-six C-class solar flares in the current study. To ascertain the relationship between ΔDVTEC and the ΔX-ray and ΔEUV fluxes, the two main ionizing radiation fluxes during flare events are used. Additionally, to identify electron density change in the ionosphere due to solar flares, we used two well-known methodologies, the baseline method and the mean method. The baseline method provides a better correlation between ΔDVTEC and ΔX-ray for X-, M-, and C-class flares. For M- and C- class flares, both methods do not show any meaningful correlation. The Solar disc location effect shows an enhanced (0.573) correlation between ΔDVTEC and ΔX-ray*cos (CMD) for the X-class flares, whereas for M- and C-class flares, no significant change was observed, which indicates feeble or no CMD effect for lower class solar flares while it is opposite for X-class flares. Here we suggest that the high solar activity, and location of the observation station to the EIA trough region might be the possible reason for the observed results.

Baricitinib in juvenile idiopathic arthritis: an international, phase 3, randomised, double-blind, placebo-controlled, withdrawal, efficacy, and safety trial

Juvenile idiopathic arthritis can be refractory to some or all treatment regimens, therefore new medications are needed to treat this population. This trial assessed the efficacy and safety of baricitinib, an oral Janus kinase 1/2-selective inhibitor, versus placebo in patients with juvenile idiopathic arthritis. This phase 3, randomised, double-blind, placebo-controlled, withdrawal, efficacy, and safety trial was conducted in 75 centres in 20 countries. We enrolled patients (aged 2 to <18 years) with polyarticular juvenile idiopathic arthritis (positive or negative for rheumatoid factor), extended oligoarticular juvenile idiopathic arthritis, enthesitis-related arthritis, or juvenile psoriatic arthritis, and an inadequate response (after ≥12 weeks of treatment) or intolerance to one or more conventional synthetic or biologic disease-modifying antirheumatic drugs (DMARDs). The trial consisted of a 2-week safety and pharmacokinetic period, a 12-week open-label lead-in period (10 weeks for the safety and pharmacokinetic subcohort), and an up to 32-week placebo-controlled double-blind withdrawal period. After age-based dosing was established in the safety and pharmacokinetic period, patients received a once-daily 4 mg adult-equivalent dose of baricitinib (tablets or suspension) in the open-label lead-in period. Patients meeting Juvenile Idiopathic Arthritis-American College of Rheumatology (JIA-ACR) 30 criteria (JIA-ACR30 responders) at the end of the open-label lead-in (week 12) were eligible for random assignment (1:1) to receive placebo or continue receiving baricitinib, and remained in the double-blind withdrawal period until disease flare or up to the end of the double-blind withdrawal period (week 44). Patients and any personnel interacting directly with patients or sites were masked to group assignment. The primary endpoint was time to disease flare during the double-blind withdrawal period and was assessed in the intention-to-treat population of all randomly assigned patients. Safety was assessed in all patients who received at least one dose of baricitinib throughout the three trial periods. For adverse events in the double-blind withdrawal period, exposure-adjusted incidence rates were calculated. The trial was registered on ClinicalTrials.gov, NCT03773978, and is completed. Between Dec 17, 2018 and March 3, 2021, 220 patients were enrolled and received at least one dose of baricitinib (152 [69%] girls and 68 [31%] boys; median age 14·0 years [IQR 12·0-16·0]). 219 patients received baricitinib in the open-label lead-in period, of whom 163 (74%) had at least a JIA-ACR30 response at week 12 and were randomly assigned to placebo (n=81) or baricitinib (n=82) in the double-blind withdrawal period. Time to disease flare was significantly shorter with placebo versus baricitinib (hazard ratio 0·241 [95% CI 0·128-0·453], p<0·0001). Median time to flare was 27·14 weeks (95% CI 15·29-not estimable) in the placebo group, and not evaluable for patients in the baricitinib group (<50% had a flare event). Six (3%) of 220 patients had serious adverse events during the safety and pharmacokinetic period or open-label lead-in period. In the double-blind withdrawal period, serious adverse events were reported in four (5%) of 82 patients (incidence rate [IR] 9·7 [95% CI 2·7-24·9] per 100 patient-years at risk) in the baricitinib group and three (4%) of 81 (IR 10·2 [2·1-29·7]) in the placebo group. Treatment-emergent infections were reported during the safety and pharmacokinetic or open-label lead-in period in 55 (25%) of 220 patients, and during the double-blind withdrawal period in 31 (38%) of 82 (IR 102·1 [95% CI 69·3-144·9]) in the baricitinib group and 15 (19%) of 81 (IR 59·0 [33·0-97·3]) in the placebo group. Pulmonary embolism was reported as a serious adverse event in one patient (1%; IR 2·4 [95% CI 0·1-13·3]) in the baricitinib group in the double-blind withdrawal period, which was judged to be related to study treatment. Baricitinib was efficacious with an acceptable safety profile in the treatment of polyarticular juvenile idiopathic arthritis, extended oligoarticular juvenile idiopathic arthritis, enthesitis-related arthritis, and juvenile psoriatic arthritis, after inadequate response or intolerance to standard therapy. Eli Lilly and Company under licence from Incyte.

Investigating the effect of large solar flares on the ionosphere based on novel Digisonde data comparing three different methods

Increased solar radiation during solar flare events can cause additional ionization and enhanced absorption of the electromagnetic (EM) waves in the ionosphere leading to partial or even total radio fade-outs. In this study, the ionospheric response to large solar flares has been investigated using the ionosonde data from Juliusruh (54.63° N, 13.37° E), Průhonice (49.98° N, 14.55° E) and San Vito (40.6° N, 17.8° E) Digisonde (DPS-4D) stations. We studied the effect of 13 intense (&amp;gt;C4.8) solar flares that occurred between 06:00 and 16:30 (UT, daytime LT = UT+1 h) from 04 to 10 September 2017 using three different methods. A novel method based on the amplitude data of the measured EM waves is used to calculate and investigate the relative absorption changes (compared to quiet period) occurring during the flares. The amplitude data are compared with the variation of the fmin parameter (fmin, the minimum measured frequency, it is considered as a qualitative proxy for the “non-deviative” radio wave absorption). Furthermore, the signal-to-noise ratio (SNR) measured by the Digisondes was used as well to quantify and characterize the fade-out events and the ionospheric absorption. In order to compare the three different methods, residuals have been defined for all parameters, which provide the percentage changes compared to the selected reference periods. Total and partial radio fade-outs, increased values (+0.4%–318%) of the fmin parameter, and +20%–1400% amplitude changes (measured at 2.5 and 4 MHz) were experienced during and after the investigated flares. Generally, the observed changes depended on the intensity, solar zenith angle and duration of the flare events. Although the three different methods have their own advantages/disadvantages and their limitations, the combination of them seems to be an efficient approach to monitor the ionospheric response to solar flares.

Solar flare phenomena forecast: solar proton events

The problems of predicting solar flare events, the only source of high-energy protons, both from the process of energy release itself and from the accompanying dynamic phenomena: shock waves and coronal mass ejections propagating from the place of energy release, are considered from modern positions. The possibility of predicting the flare events themselves ensures the interaction of new emerging magnetic fluxes with the magnetic fields of active regions and outside them, but always on the dividing line of polarities. The possibility of the release of solar protons during of a flare event is determined by the characteristics and localization of the flare event, its CME parameters, and the ratio of its energy in different radiation ranges.

Utilizing GOES-16 instruments to forecast geomagnetic storm during Solar Cycle 25

This paper focuses on the study of active region AR12891 in conjunction with geostorm from space weather data. A flare of magnitude M1.7 occurred in this active region, resulting in a geomagnetic storm of magnitude 3. By observing solar activity, x-ray flux, and radiation particle monitoring, GOES-16 instruments were used to forecast these events. A python program was used to analyze data collected from the online database of solar monitor and space weather live provided by the NOAA. Solar flare events can be studied and monitored through GOES-16 instruments to forecast geomagnetic storms. This allows less impacts towards satellite navigations and power sources if geomagnetic storm was detected early.

Multiple injections of energetic electrons associated with the flare and CME event on 9 October 2021

Context. We study the solar energetic particle (SEP) event observed on 9 October 2021 by multiple spacecraft, including Solar Orbiter. The event was associated with an M1.6 flare, a coronal mass ejection, and a shock wave. During the event, high-energy protons and electrons were recorded by multiple instruments located within a narrow longitudinal cone. Aims. An interesting aspect of the event was the multi-stage particle energisation during the flare impulsive phase and also what appears to be a separate phase of electron acceleration detected at Solar Orbiter after the flare maximum. We aim to investigate and identify the multiple sources of energetic electron acceleration. Methods. We utilised SEP electron observations from the Energetic Particle Detector (EPD) and hard X-ray (HXR) observations from the Spectrometer/Telescope for Imaging X-rays (STIX) on board Solar Orbiter, in combination with radio observations at a broad frequency range. We focused on establishing an association between the energetic electrons and the different HXR and radio emissions associated with the multiple acceleration episodes. Results. We find that the flare was able to accelerate electrons for at least 20 min during the non-thermal phase, observed in the form of five discrete HXR pulses. We also show evidence that the shock wave contributed to the electron acceleration during and after the impulsive flare phase. The detailed analysis of EPD electron data shows that there was a time difference in the release of low- and high-energy electrons, with the high-energy release delayed. Also, the observed electron anisotropy characteristics suggest a different connectivity during the two phases of acceleration.

Magnetohydrodynamics simulation of magnetic flux rope formation in a quadrupolar magnetic field configuration

Magnetic flux ropes (MFRs) play an important role in high-energetic events like solar flares and coronal mass ejections in the solar atmosphere. Importantly, solar observations suggest an association of some flaring events with quadrupolar magnetic configurations. However, the formation and subsequent evolution of MFRs in such magnetic configurations still need to be fully understood. In this paper, we present idealized magnetohydrodynamics (MHD) simulations of MFR formation in a quadrupolar magnetic configuration. A suitable initial magnetic field having a quadrupolar configuration is constructed by modifying a three-dimensional linear force-free magnetic field. The initial magnetic field contains neutral lines, which consist of X-type null points. The simulated dynamics initially demonstrate the oppositely directed magnetic field lines located across the polarity inversion lines (PILs) moving towards each other, resulting in magnetic reconnections. Due to these reconnections, four highly twisted MFRs form over the PILs. With time, the foot points of the MFRs move towards the X-type neutral lines and reconnect, generating complex magnetic structures around the neutral lines, thus making the MFR topology more complex in the quadrupolar configuration than those formed in bipolar loop systems. Further evolution reveals the non-uniform rise of the MFRs. Importantly, the simulations indicate that the pre-existing X-type null points in magnetic configurations can be crucial to the evolution of the MFRs and may lead to the observed brightenings during the onset of some flaring events in the quadrupolar configurations.

The first photometric, period variation, and flare activity studies of TIC 24233294: Reviewing with the latest results of well-studied late-type active binaries

In the current study, we present the first photometric, period variation, and flaring activity investigations of TIC 24233294. Additionally, we also review and report the flaring activity of five well-studied eclipsing binaries BX Tri, V405 And, GJ 3236, Thor 42, and GU Boo. Using the Transiting Exoplanet Survey Satellite (TESS) data, continuous variations in the light curves of binaries TIC 24233294, and BX Tri are analysed and presented. The primary and secondary components of all the six binaries in the study are M-type dwarfs. All these binaries are observed to be in detached/semi-detached configuration. Photometric analysis on TIC 24233294 and BX Tri was carried out using the Wilson–Devinney program. The long-term orbital period changes are analyzed and presented, on the basis of photometric solutions and the evolutionary status of the binary systems in the study. Flares are observed to be common in stars with outer convection zones. We identified flares on all binaries in the study and calculated their characteristic parameters like amplitudes, frequency, duration, and energies. Many superflares and few hyperflares were identified in the list of flares detected within the energy range of 1033-1037 erg. The flare events in the binaries could be related to the strong tidal interactions between the components of the binaries and fully/deeper convective interiors.

Temperature–chemistry coupling in the evolution of gas giant atmospheres driven by stellar flares

ABSTRACT The effect of enhanced UV irradiation associated with stellar flares on the atmospheric composition and temperature of gas giant exoplanets was investigated. This was done using a 1D radiative-convective-chemical model with self-consistent feedback between the temperature and the non-equilibrium chemistry. It was found that flare-driven changes to chemical composition and temperature give rise to prolonged trends in evolution across a broad range of pressure levels and species. Allowing feedback between chemistry and temperature plays an important role in establishing the quiescent structure of these atmospheres, and determines their evolution due to flares. It was found that cooler planets are more susceptible to flares than warmer ones, seeing larger changes in composition and temperature, and that temperature–chemistry feedback modifies their evolution. Long-term exposure to flares changes the transmission spectra of gas giant atmospheres; these changes differed when the temperature structure was allowed to evolve self-consistently with the chemistry. Changes in spectral features due to the effects of flares on these atmospheres can be associated with changes in composition. The effects of flares on the atmospheres of sufficiently cool planets will impact observations made with JWST. It is necessary to use self-consistent models of temperature and chemistry in order to accurately capture the effects of flares on features in the transmission spectra of cooler gas giants, but this depends heavily on the radiation environment of the planet.

MT38 Novel Data Capture Method for the Identification of Potential Flare Events in Chronic Diseases Via Patient Self-Tracking: Insights from Use Case in Sickle Cell Disease (SCD)

To describe and test the feasibility of a new method for identification and characterization of flare events.

A phase 2 trial of mosunetuzumab with lenalidomide augmentation as first-line therapy for follicular (FL) and marginal zone lymphoma (MZL).

TPS7588 Background: First-line therapy for high-burden FL and MZL includes immunochemotherapy (most commonly rituximab with bendamustine), which is associated with toxicities, is not curative, and leads to a prolonged T-cell depletion. The alternative of rituximab with full-dose lenalidomide did not improve efficacy or toxicity [Morschhauser et al., NEJM 2018]. However, lower-dose, short-course lenalidomide (15mg) may enhance cytotoxic T-cell immunity and efficacy of rituximab [Zucca et al, Blood 2019]. Mosunetuzumab is a CD20xCD3-binding, T-cell-engaging bispecific antibody approved for relapsed/refractory FL after 2 lines of therapy. It results in a complete response (CR) rate of 60% in that setting [Budde et al., Lancet Oncol, 2022], despite prior exposure to immunosuppressive therapies. This trial proposes a novel therapeutic approach to first-line treatment of FL/MZL, exploring 3 hypotheses: 1) that mosunetuzumab will lead to a high rate of CR, and possibly eradication, of FL/MZL when applied before exposure to immunosuppressive modalities; 2) that low-dose lenalidomide can augment the cytotoxic T-cell response when CR is not achieved with mosunetuzumab alone, and 3) that baseline host immune environment measured in treatment-naïve state can predict CR to bispecific antibody therapy. Methods: The Brown University Oncology Research Group BrUOG-401/ML43251 ( NCT04792502 ) is an investigator-initiated, multi-center, single-arm, phase 2 clinical trial for patients (pts) with FL and MZL in need of first-line systemic therapy. Pts with FL must meet the Groupe d’Etude des Lymphomes Folliculaires (GELF) criteria of high-burden disease, whereas pts with MZL must require therapy in the investigators’ opinion. As of January 2023, 7 of the planned 52 pts have been enrolled. The trial uses a response-adapted design: pts start with 4 courses of subcutaneous mosunetuzumab monotherapy, using step-up dosing during Cycle 1 (5mg → 45mg → 45mg) to mitigate the risk of cytokine release syndrome (CRS). Pts attaining CR (by Lugano criteria) after Cycle 4 continue for a total of 8 cycles of mosunetuzumab monotherapy. Pts attaining partial response or stable disease receive 4 additional cycles of mosunetuzumab with low-dose lenalidomide augmentation (10mg daily), with further 4 cycles of mosunetuzumab/lenalidomide if CR after C8 is still not attained. The primary endpoints include the ORR and CR rate at final assessment, and rates of toxicities, particularly CRS, tumor flare, and immune-mediated events. PFS and rate of progression of disease at 24 months (POD24) are among secondary endpoints. The study uses Simon’s two-stage design, with the null hypothesis that the CR rate is 53% (based on prior RELEVANCE trial). Correlative studies aim at determining predictive biomarkers of response, including immune signatures and dynamics of circulating tumor DNA during study therapy. Clinical trial information: NCT04792502 .

Minute-cadence observations of the LAMOST fields with the TMTS – III. Statistical study of the flare stars from the first two years

ABSTRACTTsinghua University-Ma Huateng Telescopes for Survey (TMTS) aims to detect fast-evolving transients in the Universe, which has led to the discovery of thousands of short-period variables and eclipsing binaries since 2020. In this paper, we present the observed properties of 125 flare stars identified by TMTS within the first two years, with an attempt to constrain their eruption physics. As expected, most of these flares were recorded in late-type red stars with GBP − GRP &amp;gt;2.0 mag; however, the flares associated with bluer stars tend to be on average more energetic and have broader profiles. The peak flux (Fpeak) of the flare is found to depend strongly on the equivalent duration (ED) of the energy release, i.e. Fpeak∝ED0.72 ± 0.04, which is consistent with results derived from the Kepler and Evryscope samples. This relation is likely to be related to the magnetic loop emission, while, for the more popular non-thermal electron heating model, a specific time evolution may be required to generate this relation. We notice that flares produced by hotter stars have a flatter Fpeak - ED relation compared to that from cooler stars. This is related to the statistical discrepancy in light-curve shape of flare events with different colours. In spectra from LAMOST, we find that flare stars have apparently stronger H α emission than inactive stars, especially at the low-temperature end, suggesting that chromospheric activity plays an important role in producing flares. On the other hand, the subclass with frequent flares is found to show H α emission of similar strength in its spectra to that recorded with only a single flare but similar effective temperature, implying that chromospheric activity may not be the only trigger for eruptions.

Diagnostics of Flare Loop Parameters in Shrinkage and Ascent Stages Using Radio, X-ray, and UV Emission

We propose the diagnostics of plasma parameters in flare loops using the data of multi-wavelength observations in both shrinkage and expansion phases of the loops. The approach of a flare loop as an equivalent electric circuit is applied. We show that depending on plasma loop parameters, the shrinkage may be accompanied by an increase in the electric current in the loop rather than a decrease. The number density, temperature, electric current, radius, loop-top altitude, and loop volume are determined for the flare events on 16 April 2002 and 24 August 2002.

Exploration of Imaging Biomarkers for Metabolically-Targeted Osteosarcoma Therapy in a Murine Xenograft Model.

Background: Osteosarcoma (OS) is an aggressive pediatric cancer with unmet therapeutic needs. Glutaminase 1 (GLS1) inhibition, alone and in combination with metformin, disrupts the bioenergetic demands of tumor progression and metastasis, showing promise for clinical translation. Materials and Methods: Three positron emission tomography (PET) clinical imaging agents, [18F]fluoro-2-deoxy-2-D-glucose ([18F]FDG), 3'-[18F]fluoro-3'-deoxythymidine ([18F]FLT), and (2S, 4R)-4-[18F]fluoroglutamine ([18F]GLN), were evaluated in the MG63.3 human OS xenograft mouse model, as companion imaging biomarkers after treatment for 7 d with a selective GLS1 inhibitor (CB-839, telaglenastat) and metformin, alone and in combination. Imaging and biodistribution data were collected from tumors and reference tissues before and after treatment. Results: Drug treatment altered tumor uptake of all three PET agents. Relative [18F]FDG uptake decreased significantly after telaglenastat treatment, but not within control and metformin-only groups. [18F]FLT tumor uptake appears to be negatively affected by tumor size. Evidence of a flare effect was seen with [18F]FLT imaging after treatment. Telaglenastat had a broad influence on [18F]GLN uptake in tumor and normal tissues. Conclusions: Image-based tumor volume quantification is recommended for this paratibial tumor model. The performance of [18F]FLT and [18F]GLN was affected by tumor size. [18F]FDG may be useful in detecting telaglenastat's impact on glycolysis. Exploration of kinetic tracer uptake protocols is needed to define clinically relevant patterns of [18F]GLN uptake in patients receiving telaglenastat.