Studying Magnetic Fields and Dust in M17 Using Polarized Thermal Dust Emission Observed by SOFIA/HAWC

We report on the highest spatial resolution measurement to date of magnetic fields (B-fields) in M17 using thermal dust polarization measurements taken by SOFIA/HAWC+ centered at a wavelength of 154 μm. Using the Davis–Chandrasekhar–Fermi method, in which the polarization angle dispersion calculated using the structure function technique is the quantity directly observed by SOFIA/HAWC+, we found the presence of strong B-fields of 980 ± 230 and 1665 ± 885 μG in the lower-density M17-N and higher-density M17-S regions, respectively. The B-field morphology in M17-N possibly mimics the fields in gravitationally collapsing molecular cores, while in M17-S the fields run perpendicular to the density structure. M17-S also displays a pillar feature and an asymmetric large-scale hourglass-shaped field. We use the mean B-field strengths to determine Alfvénic Mach numbers for both regions, finding that B-fields dominate over turbulence. We calculate the mass-to-flux ratio, λ, finding λ = 0.07 for M17-N and 0.28 for M17-S. These subcritical λ values are consistent with the lack of massive stars formed in M17. To study dust physics, we analyze the relationship between dust polarization fraction, p, emission intensity, I, gas column density, N(H2), polarization angle dispersion function, S, and dust temperature, T d. p decreases with intensity as I −α with α = 0.51. p tends to first increase with T d, but then decreases at higher T d. The latter feature, seen in M17-N at high T d when N(H2) and S decrease, is evidence of the radiative torque disruption effect

Prevalence and Risk Factors for Tuberculosis Infection among Hospital Workers in Hanoi, Viet Nam

BACKGROUND: Transmission of tuberculosis (TB) to health care workers (HCWs) is a global issue. Although effective infection control measures are expected to reduce nosocomial TB, HCWs' infection has not been assessed enough in TB high burden countries. We conducted a cross-sectional study to determine the prevalence of TB infection and its risk factors among HCWs in Hanoi, Viet Nam. METHODOLOGY/PRINCIPAL FINDINGS: A total of 300 HCWs including all staff members in a municipal TB referral hospital received an interferon-gamma release assay (IGRA), QuantiFERON-TB Gold In-Tube(TM), followed by one- and two-step tuberculin skin test (TST) and a questionnaire-based interview. Agreement between the tests was evaluated by kappa statistics. Risk factors for TB infection were analyzed using a logistic regression model. Among the participants aged from 20 to 58 years (median = 40), prevalence of TB infection estimated by IGRA, one- and two-step TST was 47.3%, 61.1% and 66.3% respectively. Although the levels of overall agreement between IGRA and TST were moderate, the degree of agreement was low in the group with BCG history (kappa = 0.29). Working in TB hospital was associated with twofold increase in odds of TB infection estimated by IGRA. Increased age, low educational level and the high body mass index also demonstrated high odds ratios of IGRA positivity. CONCLUSIONS/SIGNIFICANCE: Prevalence of TB infection estimated by either IGRA or TST is high among HCWs in the hospital environment for TB care in Viet Nam and an infection control program should be reinforced. In communities with heterogeneous history of BCG vaccination, IGRA seems to estimate TB infection more accurately than any other criteria using TST

The HELLP syndrome in the antiphospholipid syndrome: retrospective study of 16 cases in 15 women

Objective: To study the characteristics of the haemolysis, elevated liver enzymes, low platelets (HELLP) syndrome in the antiphospholipid syndrome (APS) and its influence on the subsequent pregnancies. Methods: This was a retrospective analysis of 16 episodes of HELLP complicating APS in 15 women. Results: HELLP was complete in 10 cases and partial in six. It occurred during the second trimester in seven cases (the earliest at 18 weeks' gestation), the third trimester in seven cases, and the day following delivery in two cases. Pre-eclampsia was present in six cases and eclampsia in five. Outcome of pregnancies was: live birth (n = 8), stillbirth (n = 2) and fetal death (n = 6). APS was primary in nine women and secondary to systemic lupus erythematosus (SLE) in six. HELLP revealed primary APS in six cases. Seven women were not treated. Low dose aspirin was empirically prescribed in one woman whose APS had been undiagnosed despite a history of two fetal deaths. In the other women, therapy consisted of aspirin (n = 8), low molecular weight heparin with a dose varying between 3000 and 12 000 U daily (n = 5), and high dose immunoglobulin every 4 weeks (n = 2), hydroxychloroquine (n = 4), and prednisone (n = 6). Six women had seven subsequent pregnancies, 3–6 years after the complicated pregnancy. HELLP recurred at 33 weeks' gestation in one woman with SLE treated with prednisone, hydroxychloroquine, aspirin, and enoxaparin, and pregnancy ended in live birth. One woman became pregnant after in vitro fertilisation and embryo transfer, but pregnancy ended in fetal death despite prednisone, hydroxychloroquine, and enoxaparin. Four women had five uneventful pregnancies with 100 mg daily aspirin and heparin. Conclusions: APS may be revealed by HELLP. In APS, HELLP is associated with pre-eclampsia/eclampsia in most cases and seems to occur earlier than in the general population. Heparin plus aspirin may prevent obstetric complications in the subsequent pregnancies

FLASH-TB: an Application of Next-Generation CRISPR to Detect Drug Resistant Tuberculosis from Direct Sputum

Offering patients with tuberculosis (TB) an optimal and timely treatment regimen depends on the rapid detection of Mycobacterium tuberculosis (Mtb) drug resistance from clinical samples. Finding Low Abundance Sequences by Hybridization (FLASH) is a technique that harnesses the efficiency, specificity, and flexibility of the Cas9 enzyme to enrich targeted sequences. Here, we used FLASH to amplify 52 candidate genes probably associated with resistance to first- and second-line drugs in the Mtb reference strain (H37Rv), then detect drug resistance mutations in cultured Mtb isolates, and in sputum samples. 92% of H37Rv reads mapped to Mtb targets, with 97.8% of target regions covered at a depth ≥ 10X. Among cultured isolates, FLASH-TB detected the same 17 drug resistance mutations as whole genome sequencing (WGS) did, but with much greater depth. Among the 16 sputum samples, FLASH-TB increased recovery of Mtb DNA compared with WGS (from 1.4% [IQR 0.5-7.5] to 33% [IQR 4.6-66.3]) and average depth reads of targets (from 6.3 [IQR 3.8-10.5] to 1991 [IQR 254.4-3623.7]). FLASH-TB identified Mtb complex in all 16 samples based on IS1081 and IS6110 copies. Drug resistance predictions for 15/16 (93.7%) clinical samples were highly concordant with phenotypic DST for isoniazid, rifampicin, amikacin, and kanamycin [15/15 (100%)], ethambutol [12/15 (80%)] and moxifloxacin [14/15 (93.3%)]. These results highlighted the potential of FLASH-TB for detecting Mtb drug resistance from sputum samples

ASSESSING DRUG SENSITIVITY OF \u3ci\u3ePLASMODIUM VIVAX\u3c/i\u3e TO HALOFANTRINE OR CHOROQUINE IN SOUTHERN, CENTRAL VIETNAM USING AN EXTENDED 28-DAY \u3ci\u3eIN VIVO\u3c/i\u3e TEST AND POLYMERASE CHAIN REACTION GENOTYPING

Chloroquine-resistant Plasmodium vivax malaria is emerging in Oceania, Asia, and Latin America. We assessed the drug sensitivity of P. vivax to chloroquine or halofantrine in two villages in southern, central Vietnam. This area has chloroquine-resistant Plasmodium falciparum but no documented chloroquine-resistant P. vivax. Standard dose chloroquine (25 mg/kg, over 48 hours) or halofantrine (8 mg/kg, 3 doses) was administered to 29 and 25 patients, respectively. End points were parasite sensitivity or resistance determined at 28 days. Of the evaluable patients, 23/23 100% (95% confidence interval [CI] 85.1–100) chloroquine and 21/24 (87.5%) (95% CI 67.6–97.3) halofantrine-treated patients were sensitive. Three halofantrine recipients had initial clearance but subsequent recurrence of their parasitemias. Genotyping of the recurrent and Day 0 parasitemias diiumffered, suggesting either new infections or relapses of liver hypnozoites from antecedent infections. Among these Vietnamese patients, P. vivax was sensitive to chloroquine and halofantrine. Genotyping was useful for differentiating the recurrent vivax parasitemias

Characterization of hospital and community-acquired respiratory syncytial virus in children with severe lower respiratory tract infections in Ho Chi Minh City, Vietnam, 2010

BackgroundHuman respiratory syncytial virus (RSV) is an important community and nosocomial pathogen in developed countries but data regarding the importance of RSV in developing countries are relatively scarce.MethodsDuring a 1-year surveillance study in 2010, we took serial samples from children admitted to the Emergency Unit of the Respiratory Ward of Children's Hospital 1 in Ho Chi Minh City, Vietnam. RSV was detected within 72hours of admission to the ward in 26% (376/1439; RSV A: n=320; RSV B: n=54; and RSV A and B: n=2). Among those negative in the first 72hours after admission, 66% (25/377) acquired nosocomial RSV infection during hospitalization (RSV A: n=22; and RSV B: n=3).ResultsChildren with nosocomial RSV infection were younger (P=0001) and had a longer duration of hospitalization (

B-fields and Dust in Interstellar Filaments Using Dust Polarization (BALLAD-POL). I. The Massive Filament G11.11–0.12 Observed by SOFIA/HAWC+

We report the first measurement of polarized thermal dust emission toward the entire infrared dark cloud G11.11−0.12 taken by the polarimeter SOFIA/HAWC+ at 214 μ m. The obtained magnetic fields ( B -fields) from the polarized emission of the early-stage and massive filament tend to be perpendicular to its spine. We produce a map of B -field strengths for the center region of the filament. The strengths vary in the range of 100–600 μ G and are strongest along the filament's spine. The central region is sub-Alfvénic and mostly subcritical, meaning that B -fields dominate over turbulence and are strong enough to resist gravitational collapse. The alignment and properties of dust grains in the filament are studied using radiative torque (RAT) theory. We find the decrease of polarization degree P with emission intensity I , i.e., depolarization effect, of the form P ∝ I ^− ^α with α ∼ 0.8–0.9, implying a significant loss of grain alignment in the filament's spine. The depolarization can be explained by the decrease in RAT alignment efficiency toward the denser regions with weaker radiation field, which cannot be explained by B -field tangling. We study the effect of the enhanced magnetic relaxation by embedded iron inclusions on RAT alignment and find that the high polarization fraction P ∼ 20%–30% in the outer layer of the filament is potential evidence for the magnetically enhanced RAT alignment mechanism. This is the first time this effect is evaluated in a filament. Based on the polarization fraction and RAT alignment theory, we also find evidence for grain growth in the filament

Modeling Extinction and Reddening Effects by Circumstellar Dust in the Betelgeuse Envelope in the Presence of Radiative Torque Disruption

International audienceCircumstellar dust forms and evolves within the envelope of evolved stars, including asymptotic giant branch (AGB) and red supergiant (RSG) stars. The extinction of stellar light by circumstellar dust is vital for interpreting RSG/AGB observations and determining high-mass RSG progenitors of core-collapse supernovae. However, circumstellar dust properties are not well understood. Modern understanding of dust evolution suggests that intense stellar radiation can radically change dust properties across the circumstellar envelope through the RAdiative Torque Disruption (RAT-D) mechanism. In this paper, we study the impacts of RAT-D on the grain size distribution (GSD) of circumstellar dust and model its effects on photometric observations of α Orionis (Betelgeuse). Due to the RAT-D effects, large grains formed in the dust formation zone are disrupted into smaller species of size a < 0.5 μm. Using the GSD constrained by the RAT-D effects, we model the visual extinction of background stars and Betelgeuse. We find that the extinction decreases at near-UV, optical, and IR wavelengths while increasing at far-UV wavelengths. The resulting flux potentially reproduces the observation from the near-UV to the near-IR range. Our results can be used to explain dust extinction and photometric observations of other RSG/AGB stars

Modeling Extinction and Reddening Effects by Circumstellar Dust in the Betelgeuse Envelope in the Presence of Radiative Torque Disruption

International audienceCircumstellar dust forms and evolves within the envelope of evolved stars, including asymptotic giant branch (AGB) and red supergiant (RSG) stars. The extinction of stellar light by circumstellar dust is vital for interpreting RSG/AGB observations and determining high-mass RSG progenitors of core-collapse supernovae. However, circumstellar dust properties are not well understood. Modern understanding of dust evolution suggests that intense stellar radiation can radically change dust properties across the circumstellar envelope through the RAdiative Torque Disruption (RAT-D) mechanism. In this paper, we study the impacts of RAT-D on the grain size distribution (GSD) of circumstellar dust and model its effects on photometric observations of α Orionis (Betelgeuse). Due to the RAT-D effects, large grains formed in the dust formation zone are disrupted into smaller species of size a < 0.5 μm. Using the GSD constrained by the RAT-D effects, we model the visual extinction of background stars and Betelgeuse. We find that the extinction decreases at near-UV, optical, and IR wavelengths while increasing at far-UV wavelengths. The resulting flux potentially reproduces the observation from the near-UV to the near-IR range. Our results can be used to explain dust extinction and photometric observations of other RSG/AGB stars

Comparative Examination of Phytonutrients and Antioxidant Activity of Commonly Consumed Nuts and Seeds Grown in Vietnam

The aim of the present study was to determine the phenolics, carotenoids, B-vitamins, and antioxidant activity of nuts and seeds grown in Vietnam. The concentrations of carotenoids and B-vitamins may vary among the nuts and seeds. Watermelon seed contained the highest level of lutein while pumpkin seed was the β-carotene richest sample. Sachi inchi and sunflower seed comprised considerable levels of vitamin B1, B6, and B9. The phenolic analysis revealed that cashew contained the highest total amount of flavonoids (466.04 μg/g), with catechin, epicatechin, and procyanidin B2 predominating over the other flavonoids. Likewise, chlorogenic and neochlorogenic acids made up the highest total amount of phenolic acids in sunflower seed (1870.41 μg/g). Walnut appeared to possess the highest antioxidant activity evaluated by DPPH, ABTS, FRAP, and reducing power assays. The correlation analysis indicated strong positive correlations between total phenolic content with DPPH and FRAP values. Principal component analysis graphically showed the distant positioning of cashew and sunflower seed, highlighting their significantly higher levels of phenolics. The findings of the study would be useful to improve nutrient database contents for flavonoids and phenolic acids as well as to promote the consumption of nut and seed products in Vietnam