Observations of the lunar exosphere provide valuable insights into dynamic processes affecting the Moon, such as meteoroid bombardment. The Chamberlain model was employed to estimate the zenith column density and temperature of Na atoms on August 13/14, 2009, after the peak of the Perseid meteor shower. Additionally, the column density and temperature of Na atoms delivered to the lunar exosphere by gradual processes during the peak on August 12/13, 2009, were estimated. Expected ratios of line-of-sight column densities of Na atoms at three observed altitudes on August 12/13, 2009, were obtained using the Chamberlain model and Monte Carlo simulations. The heightened intensities of Na emission lines on August 12/13, 2009, are attributed to the onset of the third short-term peak in Perseid activity predicted by celestial mechanics. The best agreement between observations and theoretical models was achieved with a theoretical temperature of 3000 K for impact-produced Na atoms. This third peak of Perseids began between 23:29 and 23:41 UT on August 12, 2009, lasting approximately 83 minutes, with a mass flux attributed to the Perseids ranging between 1.6 x 10^-16 and 5 x 10^-16 g cm^-2 s
We present statistical analysis of video meteor observations for the Perseid and Geminid showers taken with two camera systems operating in Hungary from the end of 2019 through 2023. Zenithal hourly rates (ZHR) and meteor fluxes, determined by MetRec-based analog video cameras HUKON, HUPIS and HUHOD, are inferred and compared with detections of slow fireballs measured at the same sites by a system consisting of automated DSLR cameras (the KoMON system).
We present the results of our Moon impact flashes detection campaigns performed around the maximum activity period of the Perseid meteor shower in 2012 and 2013. Just one flash produced by a Perseid meteoroid was detected in 2012 because of very unfavourable geometric conditions, but 12 of these were confirmed in 2013. The visual magnitude of the flashes ranged between 6.6 and 9.3. A luminous efficiency of 1.8 $\times$ 10$^{-3}$ has been estimated for meteoroids from this stream. According to this value, impactor masses would range between 1.9 and 190 g. In addition, we propose a criterion to establish, from a statistical point of view, the likely origin of impact flashes recorded on the lunar surface.
The paper describes the study of field of scattered radiation in the mesosphere basing on wide-angle polarization camera (WAPC) measurements of the twilight sky background. Mid-August observations in 2012 and 2013 show the decrease of single scattering polarization value that can be related with Perseids meteor dust moderation in the upper mesosphere. Effect correlates with activity of tiny fraction of Perseids shower. Polarization and temperature analysis allows estimating the altitude of dust layer and character polarization of dust scattering.
Influence of the meteoroid bombardment on properties of the lunar exosphere has been confirmed. Quick increase in the zenith column density of Na atoms above the lunar north pole on August 13, 2009 at 0-1 UT is detected and explained by numerous collisions of relatively small Perseid meteoroids (< 1 kg) with the Moon during maximum of the Perseid meteor shower. New stringent upper limits of the column densities for Ca, Ba, and Ti atoms in the lunar exosphere are obtained as 5*10^7, 2.2*10^6, and 6.9*10^8 cm^-2, respectively. It is found that the content of impact-produced Ca and Al atoms in the lunar exosphere is depleted as compared to that of Na atoms.
August brings four major celestial events, including a solar eclipse and the peak of the Perseid meteor shower。 Dark New Moon skies could make the Perseids especially impressive, while Venus will blaze in the west after sunset。 A deep partial lunar eclipse closes the month, darkening most of the Moon
We report the serendipitous findings of 13 faint meteors and 44 artificial space objects by Subaru SuprimeCam imaging observations during 11-16 August 2004. The meteors, at about 100km altitude, and artificial satellites/debris in orbit, at 500km altitude or higher, were clearly discriminated by their apparent defocused image sizes. CCD photometry of the 13 meteors, including 1 Perseid, 1 Aquarid, and 11 sporadic meteors, was performed. We defined a peak video-rate magnitude by comparing the integrated photon counts from the brightest portion of the track traversed within 33ms to those from a 0-mag star during the same time duration. This definition gives magnitudes in the range 4.0< V_{vr} <6.4 and 4.1< I_{vr}<5.9 for these 13 meteors. The corresponding magnitude for virtual naked-eye observers could be somewhat fainter especially for the V-band observation, in which the [OI] 5577 line lasting about 1 sec as an afterglow could contribute to the integrated flux of the present 5-10 min CCD exposures. Although the spatial resolution is insufficient to resolve the source size of anything smaller than about 1 m, we developed a new estimate of the collisionally excited colum
On 10 June 2012, an Earth-grazer meteor which lasted over 17 s with an absolute magnitude of -4.0 $\pm$ 0.5 was observed over Spain. This work focuses on the analysis of this rare event which is, to our knowledge, the faintest Earth-grazing meteor reported in the scientific literature, but also the first one belonging to a meteor shower. Thus, the orbital parameters show that the parent meteoroid belonged to the Daytime $ζ$-Perseid meteoroid stream. According to our calculations, the meteor was produced by a meteoroid with an initial mass ranging between 115 and 1.5 kg. During its encounter with Earth, the particle travelled about 510 km in the atmosphere. Around 260 g were destroyed in the atmosphere during the luminous phase of the event as a consequence of the ablation process. The modified orbit of the remaining material, which left our planet with a fusion crust, is also calculated.
The rapid expansion of the cannabis industry in Canada post-legalization has heightened the prevalence of pests, particularly the cannabis aphid Phorodon cannabis (P. cannabis), which poses significant threats to crop health. This study investigates the immediate effects of P. cannabis on Cannabis sativa (C. sativa) plants and explores biological control strategies utilizing entomopathogenic fungi. Fungal isolates of Beauveria bassiana and Metarhizium anisopliae were isolated from infected aphids, cultured, and characterized. Infection tests on aphids revealed that both fungi achieved 100% aphid mortality at high conidial concentrations (1 × 107 conidia/mL) by the 10th DAT, with Beauveria bassiana demonstrating better efficacy. In greenhouse trials on three cannabis varieties, B. bassiana effectively controlled aphid populations, keeping levels low and stable in infested plants treated with B. bassiana at the concentration of 1 × 107 conidia mL-1 (I-B) and infested plants treated with insecticide (I-I). Both I-B and I-I treatments maintained aphid populations near zero for nine weeks. In contrast, control plants showed significant aphid growth, with the Perseid variety being the most susceptible, followed by Congo Durban, while GCC exhibited the lowest susceptibility. Cannabinoid and terpene analyses revealed that treatment with insecticide substantially decreased the amount of produced cannabinoids and terpenes. In contrast, Beauveria bassiana-treated plants exhibited higher concentrations of key metabolites, including delta-9-tetrahydrocannabinolic acid and cannabidiolic acid, and total terpenes, compared to chemically treated plants, and in two out of three cultivars, these concentrations were higher than in control, untreated plants. The findings highlight Beauveria bassiana as an eco-friendly alternative for pest management that not only controls aphids effectively but also supports the biochemical quality of cannabis plants.
Atopic dermatitis (AD) is a heterogeneous inflammatory condition involving multiple immune pathways mediated by pathogenic T cells. OX40 ligand (OX40L) and OX40 are costimulatory immune checkpoint molecules that regulate effector and memory T-cell activity and promote sustained immune responses in multiple immunological pathways, including T helper (Th)2, Th1, Th17 and Th22. As such, OX40L/OX40 signalling between antigen-presenting cells (APCs) and activated T cells postantigen recognition promotes pathogenic T-cell proliferation and survival. Under inflammatory conditions, OX40L is upregulated on APCs, enhancing the magnitude of antigen-specific T-cell responses and secretion of proinflammatory cytokines. In AD, OX40L/OX40 signalling contributes to the amplification and chronic persistence of T-cell-mediated inflammation. Recent therapeutic success in clinical trials has highlighted the importance of the OX40L/OX40 axis as a promising target for the treatment of AD. Here, we discuss the many factors that are involved in the expression of OX40L and OX40, including the cytokine milieu, antigen presentation, the inflammatory environment in AD, and the therapeutic direction influenced by this costimulatory pathway. Atopic dermatitis (AD) (also known as atopic eczema) is a common skin disease caused by inflammation, and affects 2–3 of every 10 people worldwide. AD affects people of all ages and can cause a range of symptoms, including dry thickened skin, itchiness, rashes and pain. Despite the recent addition of new targeted treatment options, there is still a need for new treatments for people with moderate-to-severe AD. New drugs are being studied that target two important signalling molecules in the immune system, called OX40 ligand (OX40L) and OX40. OX40L and OX40 bind together to continue the cycle of immune system activation, leading to increasing symptoms of AD. Blocking the OX40L and OX40 interaction may ease or stop symptoms of AD. This review outlines what is currently known about the causes of AD, including the role played by the immune system and specifically the role of OX40L and OX40. We also highlight the development of new treatments that target the OX40L and OX40 interaction to treat AD, and suggest what the future may hold for managing AD.
Atopic dermatitis (AD) is a chronic, heterogeneous, inflammatory disease characterized by skin lesions, pruritus, and pain. Patients with moderate-to-severe AD experience chronic symptoms, intensified by unpredictable flares, and often have comorbidities and secondary complications, which can result in significant clinical burden that impacts the patient's overall quality of life. The complex interplay of immune dysregulation and skin barrier disruption drives AD pathogenesis, of which T-cell-dependent inflammation plays a critical role in patients with AD. Despite new targeted therapies, many patients with moderate-to-severe AD fail to achieve or sustain their individual treatment goals and/or may not be suitable for or tolerate these therapies. There remains a need for a novel, efficacious, well-tolerated therapeutic option that can deliver durable benefits across a heterogeneous AD patient population. Expression of OX40 [tumor necrosis factor receptor superfamily, member 4 (TNFRSF4)], a prominent T-cell co-stimulatory molecule, and its ligand [OX40L; tumor necrosis factor superfamily, member 4 (TNFSF4)] is increased in AD. As the OX40 pathway is critical for expansion, differentiation, and survival of effector and memory T cells, its targeting might be a promising therapeutic approach to provide sustained inhibition of pathogenic T cells and associated inflammation and broad disease control. Antibodies against OX40 [rocatinlimab (AMG 451/KHK4083) and telazorlimab (GBR 830)] or OX40L [amlitelimab (KY1005)] have shown promising results in early-phase clinical studies of moderate-to-severe AD, highlighting the importance of OX40 signaling as a new therapeutic target in AD.
The CTLA4-Ig therapeutics abatacept and belatacept inhibit CD28-mediated T cell activation by binding CD80 (B7-1) and CD86 (B7-2) co-stimulatory ligands. Both compounds preferentially bind CD80, yet CD86 has been implicated as the dominant co-stimulatory ligand. Using directed evolution methods, novel CTLA4-Ig variants were created with selective CD86 binding affinity, a property that confers increased immunosuppressive potency and potentially improved efficacy and safety profiles. Relative to abatacept (wild-type CTLA4-Ig), ASP2408 and ASP2409 have 83-fold and 220-fold enhanced binding affinity to CD86 while retaining 1.5-fold and 5.6-fold enhanced binding affinity to CD80, respectively. Improvements in CD86 binding affinity correlates with increased immunosuppressive potencyin vitroandin vivo Our results highlight the power of directed evolution methods to obtain non-intuitive protein engineering solutions and represent the first examples of CD86-selective CTLA4-Ig compounds that have entered clinical trials.
Blockade of CD28-mediated T cell costimulation by a modified cytotoxic T lymphocyte-associated antigen 4 (CTLA4-Ig), belatacept, is a clinically effective immunosuppressive therapy for the prevention of renal allograft rejection. Use of belatacept-based calcineurin inhibitor-free immunosuppression, however, has demonstrated an increased frequency of cellular rejection episodes and immunosuppression-related safety issues relative to conventional regimens. Furthermore, belatacept typically requires infusion for its administration chronically, which may present an inconvenience to patients. To address these issues, a novel CTLA4-Ig variant, ASP2409, with improved CD86 binding selectivity and affinity relative to belatacept was created using DNA shuffling directed evolution methods. We evaluated the immunosuppressive effect of ASP2409 on in vitro alloimmune T cell responses, in vivo tetanus toxoid (TTx)-induced immunological responses and renal transplantation in cynomolgus monkeys. ASP2409 had 6.1-fold higher and 2.1-fold lower binding affinity to monkey CD86 and CD80 relative to belatacept, respectively. ASP2409 was 18-fold more potent in suppressing in vitro alloimmune T cell responses relative to belatacept. In a cynomolgus monkey TTx immunization model, ASP2409 inhibited anti-TTx immune responses at a 10-fold lower dose level than belatacept. In a cynomolgus monkey renal transplantation model, subcutaneous injection of 1 mg/kg ASP2409 prevented allograft rejection through complete CD86 and partial CD80 receptor occupancies and dramatically prolonged renal allograft survival in combination with tacrolimus or mycophenolate mofetil/methylprednisolone. These results support the potential of ASP2409 as an improved CTLA4-Ig for maintenance immunosuppression in organ transplantation.
The CTLA4-Ig fusion proteins abatacept and belatacept inhibit CD28-mediated T cell activation by binding CD80 (B7-1) and CD86 (B7-2) costimulatory ligands and are clinically proven immunosuppressants used for rheumatoid arthritis and renal transplantation, respectively. Abatacept and belatacept preferentially bind CD80, yet CD86 has been implicated as the dominant ligand for CD28-mediated costimulation of T cells. We investigated the immunosuppressive effects of ASP2408, a novel CTLA4-Ig with CD86 selectivity and high potency created by directed evolution methods. Here we evaluated the effect of ASP2408 in vitro using cynomolgus monkey and rat T cell proliferation assays and in vivo using cynomolgus monkey tetanus toxoid (TTx) immunization and a rat rheumatoid arthritis model. ASP2408 was 290-fold and 21-fold more potent in suppressing in vitro monkey T cell proliferation than abatacept and belatacept, respectively. ASP2408 inhibited anti-TTx immunological reactions in cynomolgus monkey at a 10-fold lower dose level than belatacept, through complete CD86 and partial CD80 receptor occupancies, and also suppressed inflammation in the rat collagen-induced arthritis model. Overall, improved immunosuppressive potency of ASP2408 relative to abatacept and belatacept correlated well with improved CD86 binding affinity. These results may support the advantage of preferential enhancement of CD86 binding affinity to inhibit T cell-mediated immune response and improved dosing convenience in humans relative to abatacept or belatacept.
Costimulation blockade with the B7-CD28 pathway-specific agent belatacept is now used in clinical kidney transplantation, but its efficacy remains imperfect. Numerous alternate costimulatory pathways have been proposed as targets to synergize with belatacept, one of which being the inducible costimulator (ICOS)-ICOS ligand (ICOS-L) pathway. Combined ICOS-ICOS-L and CD28-B7 blockade has been shown to prevent rejection in mice, but has not been studied in primates. We therefore tested a novel ICOS-Ig human Fc-fusion protein in a nonhuman primate (NHP) kidney transplant model alone and in combination with belatacept. ICOS-Ig did not prolong rejection-free survival as a monotherapy or in combination with belatacept. In ICOS-Ig alone treated animals, most graft-infiltrating CD4(+) and CD8(+) T cells expressed ICOS, and ICOS(+) T cells were present in peripheral blood to a lesser degree. Adding belatacept reduced the proportion of graft-infiltrating ICOS(+) T cells and virtually eliminated their presence in peripheral blood. Graft-infiltrating T cells in belatacept-resistant rejection were primarily CD8(+) CD28(-) , but importantly, very few CD8(+) CD28(-) T cells expressed ICOS. We conclude that ICOS-Ig, alone or combined with belatacept, does not prolong renal allograft survival in NHPs. This may relate to selective loss of ICOS with CD28 loss.
We report on an eight year survey of simultaneous optical and radar meteor detections with the goal of isolating the fraction of meteors missed by specular radars. A total of 10,503 Electron Multiplied Charge Couple Device (EMCCD) meteors with peak brightness above +7 were simultaneously detected by the Canadian Meteor Orbit Radar (CMOR) and used to estimate the fraction of radar echoes missed as a function of speed and height. During the time period that our cameras were recording, we found some 34,119 and 18,008 meteor echoes in total occurred within the field of view of the EMCCD cameras at 29 and 38 MHz respectively. This demonstrated that a significant fraction of the specular radar echoes remain below the detection threshold of the EMCCD cameras. We used these data to derive corrections for radar-specific observing biases. The optical height distributions for six velocity bins, spanning 10 - 72 km/s were used to determine the fraction of potential radar echoes which are observed for meteors with higher begin heights ($k_c$>96) and for those with lower begin heights. When compared to the correction factors currently used in calculating shower fluxes with CMOR, mid-velocity
We have estimated the largest meteoroids present in major meteor showers from observations conducted between 2019-2022 by the Geostationary Lightning Mapper (GLM) instrument on the GOES-R satellites. Our integrated time area products for the Leonids, Perseids and eta Aquariids are of order 5 x 10^10 km2 hours. We compute photometric masses for shower fireballs using the approach of Vojacek et al. 2022 to correct from narrow-band GLM luminosity to bolometric luminosity and apply the luminous efficiency relation of Ceplecha and McCrosky 1976 at high speeds. Between 2019 and 2022, the showers definitely observed by GLM were the Leonids, Perseids, and eta Aquariids, with probable detections of the Orionids and Taurids. We find the largest meteoroids to be of order 7 kg for the Leonids, 3 kg for the Perseids, and 3 kg for the eta Aquariids, corresponding to meteoroids of ~ 0.2m diameter. The Orionids and Taurids had maximum meteoroid masses of 4 kg and 150 kg respectively. The Leonids and eta Aquariids are well fit by a single power-law with differential mass exponent, s, of 2.08 +/- 0.08 and 2.00 +/- 0.09 over the mass range 10^-7 < m < 1 kg. All showers had maximum meteoroid mas
The Subaru-Asahi StarCam is a high-sensitivity live-streaming camera for meteor observation, installed on the dome of the Subaru Telescope at the summit area of Maunakea, Hawai'i. Although it was originally intended to share the Maunakea night sky with the public, including the local Hawai'i community, the system quickly demonstrated its potential for scientific research, owing to its highly sensitive video capabilities and the exceptional fraction of clear nights at the site. The core of the StarCam system features a Sony FX3 camera body paired with an F1.4 wide-angle lens, offering a field of view of 70 deg by 40 deg. Leveraging a state-of-the-art, high-sensitivity CMOS sensor and a bright lens, the system is capable of capturing stars as faint as magnitude 8 in real-time, with an effective frame rate of 15--30 fps. Live streaming via YouTube began in April 2021, and the feed is constantly monitored by more than a hundred viewers at any given nighttime. This has enabled the camera to be used not only for observing regular meteor showers but also for monitoring scientifically important phenomena such as fireballs or unexpected meteor outbursts. Notable scientific achievements incl
We present a comprehensive morphological and spectrophotometric analysis of the lunar impact that occurred on September 11, 2013, based on pre- and post-event observations by the Lunar Reconnaissance Orbiter (LRO). The crater formed exhibits a rim-to-rim diameter of $35 \pm 0.7$ m, a depth of $4.9 \pm 0.4$ m, and an ejecta blanket extending over 2 km with an area of approximately $7 \times 10^{5}\,$m$^{2}$. The ejecta shows a pronounced asymmetry and, assuming uniform distribution, an average thickness limit of $\sim 2$ mm. Spectral analysis using WAC images reveals a consistent reddening of the central ejecta region, with an average 16.54 % increase in spectral slope between 321 nm and 643 nm, marking the first reported detection of color changes resulting from a lunar impact. We evaluated several scaling laws and found that the Gault et al. (1974) formulation most accurately reproduces the observed crater size. Furthermore, luminous efficiency values below $η= 2 \times 10^{-3}$ and higher projectile densities are most consistent with the morphology of the ejecta. The impact direction inferred from this pattern is not compatible with the radiant of the September $\varepsilon$-Pers
Meteoroid bulk density is a critical value required for assessing impact risks to spacecraft, informing shielding and mission design. Direct bulk density measurements for sub-millimeter to millimeter-sized meteoroids are difficult, often relying on forward modeling without robust uncertainty estimates. Methods based solely on select observables can overlook noise-induced biases and non-linear relations between physical parameters. This study aims to automate the inversion of meteoroid physical parameters from optical meteor data, focusing on bulk density and its associated uncertainties. We compare an observables-based selection method (PCA) with an RMSD-based approach used to select among millions of ablation model runs using full light and deceleration curves as constraints. After validating both approaches on six synthetic test cases, we apply them to two Perseid meteors recorded by high sensitivity Electron-Multiplied CCD (EMCCD) cameras and high precision mirror-tracked meteors detected by the Canadian Automated Meteor Observatory (CAMO). Our results show that relying only on observables, as in the PCA approach can converge to wrong solutions and can yield unphysical solutions