14 research outputs found
Multi-messenger observations of a binary neutron star merger
On 2017 August 17 a binary neutron star coalescence candidate (later designated GW170817) with merger time 12:41:04 UTC was observed through gravitational waves by the Advanced LIGO and Advanced Virgo detectors. The Fermi Gamma-ray Burst Monitor independently detected a gamma-ray burst (GRB 170817A) with a time delay of ~1.7 s with respect to the merger time. From the gravitational-wave signal, the source was initially localized to a sky region of 31 deg2 at a luminosity distance of 40+8-8 Mpc and with component masses consistent with neutron stars. The component masses were later measured to be in the range 0.86 to 2.26 Mo. An extensive observing campaign was launched across the electromagnetic spectrum leading to the discovery of a bright optical transient (SSS17a, now with the IAU identification of AT 2017gfo) in NGC 4993 (at ~40 Mpc) less than 11 hours after the merger by the One- Meter, Two Hemisphere (1M2H) team using the 1 m Swope Telescope. The optical transient was independently detected by multiple teams within an hour. Subsequent observations targeted the object and its environment. Early ultraviolet observations revealed a blue transient that faded within 48 hours. Optical and infrared observations showed a redward evolution over ~10 days. Following early non-detections, X-ray and radio emission were discovered at the transient’s position ~9 and ~16 days, respectively, after the merger. Both the X-ray and radio emission likely arise from a physical process that is distinct from the one that generates the UV/optical/near-infrared emission. No ultra-high-energy gamma-rays and no neutrino candidates consistent with the source were found in follow-up searches. These observations support the hypothesis that GW170817 was produced by the merger of two neutron stars in NGC4993 followed by a short gamma-ray burst (GRB 170817A) and a kilonova/macronova powered by the radioactive decay of r-process nuclei synthesized in the ejecta
Intermittent preventive therapy with sulfadoxine-pyrimethamine for malaria in pregnancy: a cross-sectional study from Tororo, Uganda.
Intermittent preventive treatment during pregnancy (IPTp) with sulfadoxine-pyrimethamine (SP) is widely recommended in sub-Saharan Africa to reduce the risk of malaria and improve birth outcomes. However, there are reports that the efficacy of IPTp with SP is waning, especially in parts of Africa where antimalarial resistance to this drug has become widespread.We conducted a cross-sectional study of 565 HIV-uninfected women giving birth at Tororo District Hospital in southeastern Uganda. The primary objective of the study was to measure associations between use of SP during pregnancy from antenatal records and the risk of adverse outcomes including placental malaria, low birth weight, maternal parasitemia and maternal anemia. The proportion of women who reported taking 0, 1, 2, and 3 doses of SP during pregnancy was 5.7%, 35.8%, 56.6% and 2.0% respectively. Overall, the prevalence of placental malaria was 17.5%, 28.1%, and 66.2% by placental smear, PCR, and histopathology, respectively. In multivariate analyses controlling for potential confounders, ≥ 2 doses of SP was associated with non-significant trends towards lower odds of placental malaria by placental smear (OR = 0.75, p = 0.25), placental malaria by PCR (OR = 0.93, p = 0.71), placental malaria by histopathology (OR = 0.75, p = 0.16), low birth weight (OR = 0.63, p = 0.11), maternal parasitemia (OR = 0.88, p = 0.60) and maternal anemia (OR = 0.88, p = 0.48). Using a composite outcome, ≥ 2 doses of SP was associated with a significantly lower odds of placental malaria, low birth weight, maternal parasitemia, or maternal anemia (OR = 0.52, p = 0.01).In this area of Uganda with intense malaria transmission, the prevalence of placental malaria by histopathology was high even among women who reported taking at least 2 doses of SP during pregnancy. The reported use of ≥ 2 doses of SP was not associated with protection against individual birth and maternal outcome measures but did protect against a composite measure of any adverse outcome
Comparative Study Assessing the Canal Cleanliness Using Automated Device and Conventional Syringe Needle for Root Canal Irrigation—An Ex-Vivo Study
The success of endodontic treatment relies on both apical and coronal sealing. To achieve a good three-dimensional seal, the removal of the smear layer becomes mandatory. This study aims to assess the difference in debris accumulation and smear layer formation while using automated root canal irrigation and conventional syringe needle irrigation. Single-rooted human mandibular premolar teeth (n = 30) which were indicated for orthodontic extractions were selected. An endodontic access cavity was prepared, and a glide path was created. Based on the irrigation protocol decided upon for the study, the teeth were randomly allocated into three study groups, namely Group 1, where the manual syringe needle irrigation method was adopted; Group 2, in which automated root canal irrigation was undertaken; and Group 3, in which teeth remained un-instrumented as it was considered the Control group. The teeth were decoronated at the cement-enamel junction (CEJ) and were subjected for scanning electron microscopy (SEM) examination. Debris and smear layers were viewed in 1000× magnification and scored. A statistically significant (p p p > 0.05) in the debris and smear layer was observed between the manual syringe needle irrigation and automated irrigation, although automated irrigation devices can be a potential alternative. The present study concluded that the efficacy of smear layer removal remained the same with both automated irrigation and manual syringe irrigation
Associations between use of IPTp-SP and outcomes at delivery.
a<p>Adjusted for maternal age, gravidity, bednet use, level of education, wealth index, and transmission season.</p>b<p>Any of the following: placental malaria by any detection method, low birth weight, maternal peripheral parasitemia, or maternal anemia.</p
Characteristics of study participants stratified by number of SP doses reported taken.
a<p>Reported 0 (n = 32) or 1 (n = 202) doses of SP taken during pregnancy.</p>b<p>Reported 2 (n = 320) or 3 (n = 11) doses of SP taken during pregnancy.</p>c<p>High transmission season May–June 2011.</p
Novel and known MYOC exon 3 mutations in an admixed Peruvian primary open-angle glaucoma population
Purpose: The aim of this study was to characterize a representative sample of the Peruvian population suffering openangle
glaucoma (OAG) with respect to the myocilin gene (MYOC) mutations, glaucoma phenotype, and ancestry for future
glaucoma risk assessment.
Methods: DNA samples from 414 unrelated Peruvian subjects, including 205 open-angle glaucoma cases (10 juvenile
glaucoma [JOAG], 19 normal-tension glaucoma [NTG], and 176 POAG) and 209 randomly sampled controls, were
screened for nucleotide changes in MYOC exon 3 by conformational sensitive gel electrophoresis (CSGE) and mutation
screening.
Results: We identified a probable causative novel MYOC missense mutation, Gly326Ser, in one POAG case and found
a consistent genotype-phenotype correlation in eight of his relatives. We also found the known causative MYOC mutation
Trp286Arg in one JOAG case and one POAG case. A known causative single base MYOC deletion, T1357, was found in
one POAG case. Two previously reported silent polymorphisms, Thr325Thr and Tyr347Tyr, were found in both the case
and the control populations. A novel missense variant, Met476Arg, was identified in two unrelated controls.
Conclusions: The screening of exon 3 of MYOC in a representative sample of 205 independent POAG patients from Peru
and 209 matched controls identified novel and previously reported mutations (both pathogenic and nonpathogenic) from
other global regions. These results reflect the complex admixture of Amerindian and Old World ancestry in urban
populations of Latin America, in general, and in Peru, in particular. It will be important to gather information about the
ancestral origin of MYOC and other POAG gene mutations to develop screening panels and risk assessment for POAG in
Peru.National Eye Institute, National Institutes
of Health, Bethesda, MD (J.E.R.), Research to Prevent
Blindness (EY011671- J.E.R.), Universidad de San Martín de
Porres Funds E10012009016, E10012009011,
E10012009027, E10012012011, Consejo Nacional de
Ciencia y Tecnología (Concytec) proyecto OAJ-2003