Magnetars are highly magnetized young neutron stars that occasionally produce enormous bursts and flares of X-rays and γ-rays
. Of the approximately thirty magnetars currently known in our Galaxy and ...the Magellanic Clouds, five have exhibited transient radio pulsations
. Fast radio bursts (FRBs) are millisecond-duration bursts of radio waves arriving from cosmological distances
, some of which have been seen to repeat
. A leading model for repeating FRBs is that they are extragalactic magnetars, powered by their intense magnetic fields
. However, a challenge to this model is that FRBs must have radio luminosities many orders of magnitude larger than those seen from known Galactic magnetars. Here we report the detection of an extremely intense radio burst from the Galactic magnetar SGR 1935+2154 using the Canadian Hydrogen Intensity Mapping Experiment (CHIME) FRB project. The fluence of this two-component bright radio burst and the estimated distance to SGR 1935+2154 together imply a burst energy at 400 to 800 megahertz of approximately 3 × 10
erg, which is three orders of magnitude higher than the burst energy of any radio-emitting magnetar detected thus far. Such a burst coming from a nearby galaxy (at a distance of less than approximately 12 megaparsecs) would be indistinguishable from a typical FRB. However, given the large gaps in observed energies and activity between the brightest and most active FRB sources and what is observed for SGR 1935+2154-like magnetars, more energetic and active sources-perhaps younger magnetars-are needed to explain all observations.
We report on the discovery of eight repeating fast radio burst (FRB) sources found using the Canadian Hydrogen Intensity Mapping Experiment (CHIME) telescope. These sources span a dispersion measure ...(DM) range of 103.5-1281 pc cm−3. They display varying degrees of activity: six sources were detected twice, another three times, and one 10 times. These eight repeating FRBs likely represent the bright and/or high-rate end of a distribution of infrequently repeating sources. For all sources, we determine sky coordinates with uncertainties of ∼10′. FRB 180916.J0158+65 has a burst-averaged DM = 349.2 0.3 pc cm−3 and a low DM excess over the modeled Galactic maximum (as low as ∼20 pc cm−3); this source also has a Faraday rotation measure (RM) of −114.6 0.6 rad m−2, which is much lower than the RM measured for FRB 121102. FRB 181030.J1054+73 has the lowest DM for a repeater, 103.5 0.3 pc cm−3, with a DM excess of ∼70 pc cm−3. Both sources are interesting targets for multi-wavelength follow-up due to their apparent proximity. The DM distribution of our repeater sample is statistically indistinguishable from that of the first 12 CHIME/FRB sources that have not yet repeated. We find, with 4 significance, that repeater bursts are generally wider than those of CHIME/FRB bursts that have not repeated, suggesting different emission mechanisms. Many of our repeater events show complex morphologies that are reminiscent of the first two discovered repeating FRBs. The repetitive behavior of these sources will enable interferometric localizations and subsequent host galaxy identifications.
We conducted a qualitative study aiming to understand the process of diagnosis disclosure in a group of HIV-infected adolescents/young adults, aware of their serological 'status', and among their ...caretakers, as well as its possible consequences. Data collection were carried out through semi-structured interviews with 40 adolescents/young adults, and with the caretakers of the patients under 18 years old, in a referral hospital in Rio de Janeiro, Brazil, in 2016. Results signalized that the HIV diagnosis disclosure was made usually by a close relative. Most of the adolescents/young adults claimed that they feel 'normal', despite the difficulties in sharing the diagnosis outside the family, and report feelings of rejection and social prejudice. The caretakers' points of view coincided with the adolescents' observations. We suggest that the diagnosis disclosure should not be postponed, since patients who underwent an adequate process of disclosure may more likely complied to treatment and experienced a better social insertion.
The potential adverse effects of antiretroviral drugs during pregnancy are discrepant and few studies, mostly from Europe, have provided information about pregnancy outcomes of those already on ...treatment at conception. The aim of this study was to investigate the impact of antiretrovirals (ARVs) on pregnancy outcome according to the timing of treatment initiation in a cohort of pregnant women from Brazil infected with HIV.
A prospective cohort of 696 pregnant women followed up in one single centre between 1996 and 2006 was studied. Patients who had ARV treatment before pregnancy were compared with those treated after the first trimester. The outcomes evaluated were preterm delivery (PTD) (<37 weeks), severe PTD (<34 weeks), low birth weight (LBW) (<2500 g) and very LBW (<1500 g).
Patients who were using ARVs pre-conception had higher rates of LBW (33.3% vs 16.5%; p<0.001) and a similar trend for PTD (26.3% vs 17.7%; p = 0.09). Stratification by type of therapy (dual vs highly active antiretroviral therapy (HAART)) according to timing of initiation of ARVs showed that patients who use HAART pre-conception have a higher rate of PTD (20.2% vs 10.2%; p = 0.03) and LBW (24.2% vs 10.2%; p = 0.002). After adjusting for several factors, HAART used pre-conception was associated with an increased risk for PTD (AOR 5.0; 95% CI 1.5 to 17.0; p = 0.009) and LBW (OR 3.6; 95% CI 1.7 to 7.7; p = 0.001).
We identified an increased risk for LBW and PTD in patients who had HAART prior to pregnancy.
The aim of this study is to evaluate the characteristics of pregnant women whether they are HIV infected or not and their prenatal care. It is a cross-sectional study. HIV-infected women were derived ...from a cohort study of all HIV-infected pregnant women followed from 1995 to 2005, at the Instituto de Puericultura e Pediatria Martagão Gesteira - Rio de Janeiro. HIV-non-infected women were derived from a random sample of all pregnant women who gave birth at Rio de Janeiro municipality between 1999 and 2001. All relevant sociodemographic, clinical, and pregnancy outcomes data were retrieved from both studies. To evaluate the prenatal care, we calculated the Kotelchuck Modified Index (KMI). The index is based on the months of initiation of prenatal care and the proportion of visits observed in each trimester, according to gestational age at birth. Comparisons were performed using Student t- and chi-square tests. Variables with p-value < 0.25 were included in an unconditional logistic regression model. There were 713 HIV-infected women and 2145 HIV-non-infected women. Variables independently associated with HIV status were: inadequate KMI (OR=4.08, 95% CI=3.17-5.24); lower educational level (OR=1.32, 95% CI=1.04-1.68); does not live with a partner (OR=3.54, 95% CI=2.66-4.64); lower family income (OR=4.71, 95% CI=3.62-6.14); tobacco use (OR=2.17, 95% CI=1.63-2.88); and hypertension (OR=1.47, 95% CI=1.01-2.17). Prematurity was not independently associated with HIV status. Although in Brazil, the HIV care is free of charge, pregnant women are still having difficulty to reach the specialized care. Better access to care must be offered to this population and studies of prematurity in the HIV-infected women must evaluate their prenatal care.
Celotno besedilo
Dostopno za:
DOBA, IJS, IZUM, KILJ, NUK, OILJ, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK, VSZLJ
Chronic non-bacterial osteomyelitis (CNO) is a rare non-infectious bone inflammatory disorder; when multifocal, it is referred to as Chronic Recurrent Multifocal Osteomyelitis (CRMO). This study ...evaluates the demographic, clinical and radiological characteristics of a multi-centre cohort of patients with CNO/CRMO.
Demographic and clinical data of patients with an established diagnosis of CNO/CRMO followed at paediatric rheumatology centres across Europe (Italy, France, Slovenia) and India were retrospectively collected.
There were no demographic differences across countries, but time to diagnosis was significantly longer in India (p=0.041). Pain was almost invariably present at disease onset; functional impairment was more frequent among Italian and Slovenian patients (p=0.001). The number of sites of bone involvement was similar between genders and countries, with long bone metaphises being the most common site. Raised acute phase reactants, detected in >50% of patients, were not associated with clinical manifestations or response to treatment. Comorbidities, evinced in 37% of patients, were equally distributed between genders and nationalities. Imaging approach was similar across countries, without any association between radiological findings and clinical manifestations. NSAIDs were almost invariably used as first-line treatment, but response rate was significantly lower in Italy (p=0.02). Methotrexate was used in 28% of case, with an overall rate of response of 82%. Health conditions and rate of permanent deformities were similar across different countries.
The differences in clinical presentation, radiological features and response to treatment described in this multinational cohort of CNO/CRMO might provide novel insights into this still elusive disease.
OBJECTIVE:Brazil provides antiretroviral therapy (ART) to HIV-infected persons free of charge. The objective of this study was to investigate factors associated with ART failure in patients receiving ...free ART in public clinics in Brazil.
METHODS:This is a cross-sectional study of adults taking ART for 6 to 24 months in 5 public clinics in Rio de Janeiro. Patients were interviewed and their charts were reviewed. The following definitions of response to therapy at 6 months were usedvirologic responders (VR), ≥1 log reduction in plasma viral load (VL); immunologic responders (IR), increase of ≥50 CD4 cells/mL; complete responders (CR), both VR and IR; and nonresponders (NR), neither VR nor IR.
RESULTS:Of 211 patients enrolled, 173 (82%) were VR, IR, or CR and 38 (18%) were NR. Of the responders, 28 (13%) were IR, 32 (15%) were VR, and 113 (53%) were CR. In multivariate analysis, factors associated with NR were less than 80% adherence (OR = 8.6; 95% CI, 2.9–25.7), baseline CD4 count (OR = 0.5 per 50 cells/mL; 95% CI, 0.2–1.1), interval between starting ART and first VL/CD4 testing (OR = 1.4 for each month; 95% CI, 1.1–1.8), opportunistic disease after starting ART (OR = 6.8; 95% CI, 1.4–34.0), inability to read prescription (OR = 3.9; 95% CI, 1.4–10.9), not believing physician is knowledgeable about HIV (OR = 4.0; 95% CI, 1.1–15.0), not having a friend with HIV (OR = 6.1; 95% CI, 1.7–21.8), believing ART will make him/her ill (OR = 5.6; 95% CI, 1.7–18.8), and believing ART will delay HIV progression (OR = 0.001; 95% CI, 0.0–0.2).
CONCLUSION:The proportion of patients responding to ART in Brazil was similar to reports from developed countries, suggesting that ART can be used successfully in developing countries. Variables related to adherence, knowledge, and perceptions about ART were associated with a lack of response to ART. These findings have important implications for developing nations that are considering increased access to ART.
Fast radio bursts (FRBs) are bright, millisecond-duration radio transients originating from sources at extragalactic distances
, the origin of which is unknown. Some FRB sources emit repeat bursts, ...ruling out cataclysmic origins for those events
. Despite searches for periodicity in repeat burst arrival times on timescales from milliseconds to many days
, these bursts have hitherto been observed to appear sporadically and-although clustered
-without a regular pattern. Here we report observations of a 16.35 ± 0.15 day periodicity (or possibly a higher-frequency alias of that periodicity) from the repeating FRB 180916.J0158+65 detected by the Canadian Hydrogen Intensity Mapping Experiment Fast Radio Burst Project
. In 38 bursts recorded from 16 September 2018 to 4 February 2020 UTC, we find that all bursts arrive in a five-day phase window, and 50 per cent of the bursts arrive in a 0.6-day phase window. Our results suggest a mechanism for periodic modulation either of the burst emission itself or through external amplification or absorption, and disfavour models invoking purely sporadic processes.
Abstract
Background
Clinical audits aim to ensure ideal use of ionizing radiation in clinical practice. Since it became mandatory by Swiss law in 2018, such an audit also took place in our Cardiac ...Pacing and Electrophysiology Division at the University Heart Center.
Purpose
To establish local diagnostic reference levels (DRLs) for specific procedures and to examine if patient radiation exposure was reduced after the clinical audit.
Methods
Retrospective cohort study including patients from October 2018 to October 2020 who underwent device implantation, including pacemakers, implantable cardioverter defibrillators (ICD), cardiac resynchronization therapy (CRT), or lead extraction / device explantation. Main measures to reduce radiation exposure after the audit were lower pulsed fluoroscopy frame rates and dose characteristics at baseline. Patient radiation exposure was evaluated with the dose-area product (DAP), cumulative dose, fluoroscopy time, and the number of cine acquisitions. Secondary endpoints included the effective dose, the acute procedural success rate and 30-day complications. Data were collected from a dose management system and cross-checked for accuracy with the patient information system. The third quartiles were set as local DRLs. Data before and after the clinical audit were compared.
Results
A total of 541 patients (45.7 % before the audit, 54.3% after the audit) were included. 28.3% had a conventional pacemaker, 22.0% a leadless pacemaker, 21.1% an ICD, and 17.2% a CRT implantation. Lead extraction / device explantation was undergone by 11.5% of patients. The local DRLs (including all procedures before and after the audit) for the DAP were significantly lower as compared to national DRLs (6.2 dGy.cm2 versus 300 dGy.cm2 for conventional pacemakers; 7.6 dGy.cm2 versus 200 dGy.cm2 for ICDs, 203 dGy.cm2 versus 570 dGy.cm2 for CRTs). After the audit, DAP (Figure 1), cumulative dose, effective dose and the number of cine acquisition significantly decreased for conventional pacemakers (p-value ≤ 0.04), whereas no significant differences were observed for the other procedures. The acute procedural success rate (98.4 vs 98.9%) and the 30-day complications (4.0 vs 7.8%) were not significantly different before and after the audit.
Conclusions
The clinical audit in our institution led to a significant reduction of radiation exposure for patients during pacemaker implantations. Regarding DRLs, local values were far below national DRLs, which suggests that national DRLs need to be updated more regularly. Our study highlights the importance of clinical audits and the need for more research in this field.
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