We report on the detection of seven bursts from the periodically active, repeating fast radio burst (FRB) source FRB 180916.J0158+65 in the 300-400 MHz frequency range with the Green Bank Telescope ...(GBT). Emission in multiple bursts is visible down to the bottom of the GBT band, suggesting that the cutoff frequency (if it exists) for FRB emission is lower than 300 MHz. Observations were conducted during predicted periods of activity of the source, and had simultaneous coverage with the Low Frequency Array (LOFAR) and the FRB backend on the Canadian Hydrogen Intensity Mapping Experiment (CHIME) telescope. We find that one of the GBT-detected bursts has potentially associated emission in the CHIME band (400-800 MHz) but we detect no bursts in the LOFAR band (110-190 MHz), placing a limit of on the spectral index of broadband emission from the source. We also find that emission from the source is severely band-limited with burst bandwidths as low as ∼40 MHz. In addition, we place the strictest constraint on observable scattering of the source, <1.7 ms at 350 MHz, suggesting that the circumburst environment does not have strong scattering properties. Additionally, knowing that the circumburst environment is optically thin to free-free absorption at 300 MHz, we find evidence against the association of a hyper-compact H ii region or a young supernova remnant (age <50 yr) with the source.
Abstract
We present a Monte Carlo–based population synthesis study of fast radio burst (FRB) dispersion and scattering focusing on the first catalog of sources detected with the Canadian Hydrogen ...Intensity Mapping Experiment Fast Radio Burst (CHIME/FRB) project. We simulate intrinsic properties and propagation effects for a variety of FRB population models and compare the simulated distributions of dispersion measures and scattering timescales with the corresponding distributions from the CHIME/FRB catalog. Our simulations confirm the results of previous population studies, which suggested that the interstellar medium of the host galaxy alone (simulated based on the NE2001 model) cannot explain the observed scattering timescales of FRBs. We therefore consider additional sources of scattering, namely, the circumgalactic medium (CGM) of intervening galaxies and the circumburst medium whose properties are modeled based on typical Galactic plane environments. We find that a population of FRBs with scattering contributed by these media is marginally consistent with the CHIME/FRB catalog. In this scenario, our simulations favor a population of FRBs offset from their galaxy centers over a population that is distributed along the spiral arms. However, if the models proposing the CGM as a source of intense scattering are incorrect, then we conclude that FRBs may inhabit environments with more extreme properties than those inferred for pulsars in the Milky Way.
Abstract
We investigate whether the sky rate of fast radio bursts (FRBs) depends on Galactic latitude using the first catalog of FRBs detected by the Canadian Hydrogen Intensity Mapping Experiment ...Fast Radio Burst (CHIME/FRB) Project. We first select CHIME/FRB events above a specified sensitivity threshold in consideration of the radiometer equation, and then we compare these detections with the expected cumulative time-weighted exposure using Anderson–Darling and Kolmogorov–Smirnov tests. These tests are consistent with the null hypothesis that FRBs are distributed without Galactic latitude dependence (
p
-values distributed from 0.05 to 0.99, depending on completeness threshold). Additionally, we compare rates in intermediate latitudes (∣
b
∣ < 15°) with high latitudes using a Bayesian framework, treating the question as a biased coin-flipping experiment–again for a range of completeness thresholds. In these tests the isotropic model is significantly favored (Bayes factors ranging from 3.3 to 14.2). Our results are consistent with FRBs originating from an isotropic population of extragalactic sources.
Research Objective
Expanding home‐ and community‐based services (HCBS) as an alternative to nursing home care has become a priority for many state Medicaid programs. Whereas low‐income people with ...long‐term care needs used to have little choice but to move to a nursing home if they needed extensive assistance funded by Medicaid, now more than half of all Medicaid long‐term care funding goes to HCBS, with substantial variation by state and county. This shift in policy was motivated by widespread consumer preferences to avoid institutionalization and the hope that HCBS would save Medicaid money relative to nursing home care.
However, these dramatic policy changes are being made on the basis of surprisingly little evidence about the outcomes of HCBS. HCBS inevitably involves a lower intensity of care than nursing home care and shifts some of the burden of care to untrained caregivers. Recent descriptive evidence shows higher hospitalization rates among HCBS users than nursing home residents, but descriptive correlations may suffer from selection bias. Our study provides the first plausibly causal national estimates of health outcomes for recipients of Medicaid HCBS relative to nursing home care and explores possible mechanisms for the effect.
Study Design
We use 2005 and 2012 Medicaid Analytic Extract (MAX) data set, a national compilation of Medicaid claims, in a longitudinal instrumental variables framework. We combine the MAX data with Medicare claims to identify hospital admissions, our main outcome variable, and with state and county data on the percent of individuals receiving HCBS versus nursing home care. To address the endogeneity of HCBS receipt, we instrument for it using the county percentage of nonelderly long‐term care users who receive HCBS. The percentage of nonelderly users is highly predictive of HCBS use for an elderly beneficiary, but because the instrument was derived from a separate population, the exclusion restriction is unlikely to be violated.
Population Studied
Older adults (65+) dually enrolled in Medicaid and Medicare. We also examine heterogeneity of the effects by race/ethnicity and the presence of dementia.
Principal Findings
HCBS users have 13 percentage‐point higher annual rates of hospitalization than their nursing home counterparts when selection bias is addressed, with an even larger difference among those with dementia. These differences exist within as well as across counties, ruling out differences in state policy or county‐level health infrastructure as primary explanations. Differences are smaller for those receiving more intensive HCBS. Furthermore, we find significant disparities by race, with blacks using HCBS at higher rates than whites but experiencing higher rates of hospitalization.
Conclusions
Shifting long‐term care for older adults from nursing homes to HCBS, while well motivated, results in the unintended consequence of substantially higher hospitalization rates and potentially exacerbates disparities by race. The intensity of services may be inadequate for some HCBS recipients.
Implications for Policy or Practice
Hospitalizations are costly to Medicare but also to the HCBS recipient in terms of stress and risks. Although consumer preferences to remain at home may outweigh poor outcomes of HCBS, the full costs and benefits need to be considered. HCBS outcomes—not just expansion—need more attention.
Primary Funding Source
National Institutes of Health.
Periodontitis is a prevalent condition significantly affecting oral health. Comorbid conditions, such as diabetes, can heighten the severity of periodontal disease and overall oral health. Therefore, ...to enhance oral health and manage comorbid conditions, comprehensive periodontal care is essential. This approach could involve using toothpaste containing antimicrobial ingredients in routine oral care. This paper presents the results of an in vitro study analysing the antimicrobial properties of the test formulation containing zinc citrate, alum, sodium fluoride, and xylitol-based toothpaste (Stolin-R). These ingredients work together to help in providing comprehensive oral care by controlling growth of bacteria majorly responsible for periodontal disease and thus maintaining optimal oral hygiene.
To determine the antimicrobial properties of zinc citrate, alum, sodium fluoride, and xylitol-based toothpaste formulation against key periodontal pathogens through in vitro analyses.
The antimicrobial efficacy of test formulation is evaluated through minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC), and time-dependent antibacterial assessment against key periodontal pathogens, including
, and
.
The test formulation demonstrated potent antimicrobial effectiveness against
, and
, by exhibiting low MIC and MBC. Additionally, significant bacterial reduction, exceeding 99.99%, was observed within five minutes, emphasising its potential as an effective adjunct in combating periodontal infection.
Zinc citrate, alum, sodium fluoride, and xylitol-based toothpaste formulation demonstrates significant antimicrobial activity against key periodontal pathogens, suggesting its potential as an effective agent for maintaining oral health and combating gingival infection.
We previously reported that posttransplant alloantibody production in CD8‐deficient hosts is IL‐4+CD4+ T cell–dependent and IgG1 isotype‐dominant. The current studies investigated the hypothesis that ...IL‐4‐producing natural killer T cells (NKT cells) contribute to maximal alloantibody production. To investigate this, alloantibody levels were examined in CD8‐deficient WT, CD1d KO and Jα18 KO transplant recipients. We found that the magnitude of IgG1 alloantibody production was critically dependent on the presence of type I NKT cells, which are activated by day 1 posttransplant. Unexpectedly, type I NKT cell contribution to enhanced IgG1 alloantibody levels was interferon‐γ‐dependent and IL‐4‐independent. Cognate interactions between type I NKT and B cells alone do not stimulate alloantibody production. Instead, NKT cells appear to enhance maturation of IL‐4+CD4+ T cells. To our knowledge, this is the first report to substantiate a critical role for type I NKT cells in enhancing in vivo antibody production in response to endogenous antigenic stimuli.
Using a murine transplant model, the authors report a novel type I natural killer T cell–mediated mechanism that enhances the magnitude of IgG1 alloantibody production posttransplant.
While it is well known that CD4+ T cells and B cells collaborate for antibody production, our group previously reported that CD8+ T cells down‐regulate alloantibody responses following ...transplantation. However, the exact mechanism involved in CD8+ T cell–mediated down‐regulation of alloantibody remains unclear. We also reported that alloantibody production is enhanced when either perforin or FasL is deficient in transplant recipients. Here, we report that CD8+ T cell–deficient transplant recipient mice (high alloantibody producers) exhibit an increased number of primed B cells compared to WT transplant recipients. Furthermore, CD8+ T cells require FasL, perforin and allospecificity to down‐regulate posttransplant alloantibody production. In vivo CD8‐mediated clearance of alloprimed B cells was also FasL‐ and perforin‐dependent. In vitro data demonstrated that recipient CD8+ T cells directly induce apoptosis of alloprimed IgG1+ B cells in co‐culture in an allospecific and MHC class I‐dependent fashion. Altogether these data are consistent with the interpretation that CD8+ T cells down‐regulate posttransplant alloantibody production by FasL‐ and perforin‐dependent direct elimination of alloprimed IgG1+ B cells.
Using a murine transplant model, the authors report that alloprimed CD8+ T cells use perforin and FasL to downregulate alloantibody production by eliminating alloprimed IgG1+ B cells. See online supporting information for 3‐dimensional figures of colocalized CD8+ T cells and B cells.
The DNA repair process protects the cells from DNA damaging agent by multiple pathways. Majority of the cancer therapy cause DNA damage which leads to apoptosis. The cell has natural ability to ...repair this damage which ultimately leads to development of resistance of drugs. The key enzymes involved in DNA repair process are poly(ADP-ribose) (PAR) and poly(ADP-ribose) polymerases (PARP). Tumor cells repair their defective gene via defective homologues recombination (HR) in the presence of enzyme PARP. PARP inhibitors inhibit the enzyme poly(ADP-ribose) polymerases (PARPs) which lead to apoptosis of cancer cells. Current clinical data shows the role of PARP inhibitors is not restricted to BRCA mutations but also effective in HR dysfunctions related tumors. Therefore, investigation in this area could be very helpful for future therapy of cancer. This review gives detail information on the role of PARP in DNA damage repair, the role of PARP inhibitors and chemistry of currently available PARP inhibitors.
Fungal lung co-infections associated with COVID-19 may occur in severely ill patients or those with underlying co-morbidities, and immunosuppression. The most common invasive fungal infections are ...caused by aspergillosis, mucormycosis, pneumocystis, cryptococcus, and candida. Radiologists integrate the clinical disease features with the CT pattern-based approach and play a crucial role in identifying these co-infections in COVID-19 to assist clinicians to make a confident diagnosis, initiate treatment and prevent complications.
Las coinfecciones pulmonares fúngicas asociadas a la COVID-19 pueden ocurrir en pacientes gravemente enfermos o con comorbilidades subyacentes e inmunosupresión. Las infecciones fúngicas invasivas más comunes son causadas por aspergilosis, mucormicosis, y las debidas a Pneumocystis, criptococo y cándida. Los radiólogos integran las características clínicas de la enfermedad con el enfoque basado en patrones de TAC y desempeñan un papel crucial en la identificación de estas coinfecciones en la COVID-19 para ayudar a los médicos a realizar un diagnóstico seguro, iniciar el tratamiento y prevenir complicaciones.
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