On the nature of the fourth generation neutrino and its implications

We consider the neutrino sector of a Standard Model with four generations. While the three light neutrinos can obtain their masses from a variety of mechanisms with or without new neutral fermions, fourth-generation neutrinos need at least one new relatively light right-handed neutrino. If lepton number is not conserved this neutrino must have a Majorana mass term whose size depends on the underlying mechanism for lepton number violation. Majorana masses for the fourth generation neutrinos induce relative large two-loop contributions to the light neutrino masses which could be even larger than the cosmological bounds. This sets strong limits on the mass parameters and mixings of the fourth generation neutrinos.Comment: To be published. Few typos corrected, references update

Star clusters near and far; tracing star formation across cosmic time

© 2020 Springer-Verlag. The final publication is available at Springer via https://doi.org/10.1007/s11214-020-00690-x.Star clusters are fundamental units of stellar feedback and unique tracers of their host galactic properties. In this review, we will first focus on their constituents, i.e.\ detailed insight into their stellar populations and their surrounding ionised, warm, neutral, and molecular gas. We, then, move beyond the Local Group to review star cluster populations at various evolutionary stages, and in diverse galactic environmental conditions accessible in the local Universe. At high redshift, where conditions for cluster formation and evolution are more extreme, we are only able to observe the integrated light of a handful of objects that we believe will become globular clusters. We therefore discuss how numerical and analytical methods, informed by the observed properties of cluster populations in the local Universe, are used to develop sophisticated simulations potentially capable of disentangling the genetic map of galaxy formation and assembly that is carried by globular cluster populations.Peer reviewedFinal Accepted Versio

Updating the approaches to define susceptibility and resistance to anti-tuberculosis agents: implications for diagnosis and treatment

11 páginas, 2 figuras, 1 tablaInappropriately high breakpoints have resulted in systematic false-susceptible AST results to anti-TB drugs. MIC, PK/PD and clinical outcome data should be combined when setting breakpoints to minimise the emergence and spread of antimicrobial resistance.I. Comas was supported by PID2019-104477RB-I00 from the Spanish Science Ministry and by ERC (CoG 101001038)Peer reviewe

Applying the Infectious Diseases Literature to People who Inject Drugs

People who inject drugs (PWID) presenting with injection drug use-associated infections are an understudied population excluded from most prospective infectious disease (ID) clinical trials. Careful application of the existing ID literature to PWID must consider their unique medical, psychological, and social challenges. Identification and treatment of the underlying substance use disorder are key underpinnings to any successful ID intervention

1020. Injection Drug Use-Associated Staphylococcus aureus Bacteremia in a Large Urban Hospital in Atlanta, Georgia

Abstract Background Infectious complications of injection drug use (IDU) have increased with the expanding opioid epidemic in the southeast. We assessed the incidence, clinical presentation, and treatment outcomes of IDU-associated Staphylococcus aureus (SA) bacteremia (SAB). Methods We created a retrospective cohort of all adults with community acquired (CA) SAB over 5 years presenting to Grady Memorial Hospital, a 1,000-bed urban county hospital in Atlanta, GA. Charts were reviewed by infectious diseases physicians to obtain clinical and laboratory characteristics, including substance use disorder (SUD), and determine if SAB was IDU-associated. The study period was divided into three periods (P1 = March 2012–January 2014, P2 = January 2014–December 2015, P3 = December 2015–November 2017) to evaluate changes in the incidence of IDU-SAB over time using Poisson regression. Results Among 321 patients with a first episode of CA-SAB, 24 (7%) were IDU-SAB. The number of IDU-SAB cases in each period increased (P1 = 4, P2 = 7, and P3 = 13 [P = 0.07 for trend]). The median age of IDU-SAB patients was 38 (IQR 31–57), 11 (46%) were black, and 15 (63%) had chronic hepatitis C virus infection. Heroin was the most common injected drug (92%) followed by cocaine (25%); multiple drugs were injected in 29%. All but two patients (92%) had a complication of SAB, most commonly endocarditis (50%) and septic pulmonary emboli (38%). The median hospitalization was 23 days (IQR 19.5–37.5) and 5 patients (12%) left the hospital against medical advice (AMA). Readmission for persistent or recurrent SA infection during the study period was common (42%), and three (13%) died ≤6 months from initial presentation, including two with prior discharge AMA. Half of the discharge summaries did not mention SUD as a hospital problem. Outpatient SUD treatment was recommended to eight (33%) patients and a recommendation of abstinence was the intervention for 12 (50%). Conclusion Increasing IDU-SAB was observed over 5 years in our urban Atlanta hospital, primarily due to heroin use. Most cases were associated with complications of SAB with a long length of stay and frequent readmission, but few patients received treatment or harm reduction interventions for their SUD. These data will raise awareness and direct resources to expanding evidence-based opioid use disorder treatment for patients with infectious complications of IDU. Disclosures All authors: No reported disclosures

Disparity in Quality of Infectious Disease vs Addiction Care Among Patients With Injection Drug Use–Associated Staphylococcus aureus Bacteremia

Abstract Evidence-based interventions for Staphylococcus aureus bacteremia (SAB) are well known, but it is unclear how they are implemented among patients with injection drug use–associated (IDU) SAB. Of 46 patients with IDU-SAB identified, all received high-quality SAB management; however, few received appropriate recognition or treatment of their underlying substance use disorder

Three galactic globular cluster candidates

‘In these times, during the rise in the popularity of institutional repositories, the Society does not forbid authors from depositing their work in such repositories. However, the AAS regards the deposit of scholarly work in such repositories to be a decision of the individual scholar, as long as the individual's actions respect the diligence of the journals and their reviewers.’ Original article can be found at : http://iopscience.iop.org/ Copyright American Astronomical SocietyContext. The census of Galactic globular clusters (GCs) is still incomplete, and about ten new objects are supposed to await discovery, hidden behind the crowded and reddened regions of the Galactic bulge and disk. Aims. We investigated the nature of three new GC candidates, discovered in the frames collected by the Vista Variables in the Via Lactea (VVV) near-infrared survey. They will be called VVV CL002, VVV CL003, and VVV CL004. Methods. We studied the results of point-spread-function near-infrared photometry from VVV data for the three objects and their surrounding fields, the proper motion information available in the literature and, when possible, we derived the cluster parameters by means of calibrated indices measured on the color-magnitude diagrams. Results. The evidence shows that VVV CL002 is a newly discovered, small, moderately metal-rich ([Fe/H] ∼-0.4) Galactic GC. It is located at a Galactocentric distance of 0.7 ± 0.9 kpc, and it could be one of the nearest GC to the Galactic center. Its characteristics are more similar to those of low-mass, Palomar-like GCs than to more classical, old, and massive bulge GCs. VVV CL003 is the first star cluster discovered in the Galactic disk on the opposite side of the center with respect to the Sun, at a Galactocentric distance of ∼5 kpc. Its high metallicity ([Fe/H] ≈-0.1) and location point to an open cluster, but a GC cannot be excluded. VVV CL004, on the contrary, is most probably only a random clump of field stars, as indicated by both its low statistical significance and by the impossibility to distinguish its stars from the surrounding field population. Conclusions. We claim the detection of i) a new Galactic GC, deriving an estimate of its basic parameters; ii) a stellar aggregate, probably an open cluster, in the disk directly beyond the Galactic center; and iii) an overdensity of stars, most probably an asterism.Peer reviewedFinal Accepted Versio

Inactivation of vesicular stomatitis virus through inhibition of membrane fusion by chemical modification of the viral glycoprotein

Membrane fusion is an essential step in the entry of enveloped viruses into their host cells triggered by conformational changes in viral glycoproteins. We have demonstrated previously that modification of vesicular stomatitis virus (VSV) with diethylpyrocarbonate (DEPC) abolished conformational changes on VSV glycoprotein and the fusion reaction catalyzed by the virus. In the present study, we evaluated whether treatment with DEPC was able to inactivate the virus. Infectivity and viral replication were abolished by viral treatment with 0.5 mM DEPC. Mortality profile and inflammatory response in the central nervous system indicated that G protein modification with DEPC eliminates the ability of the virus to cause disease. In addition, DEPC treatment did not alter the conformational integrity of surface proteins of inactivated VSV as demonstrated by transmission electron microscopy and competitive ELISA. Taken together, our results suggest a potential use of histidine (His) modification to the development of a new process of viral inactivation based on fusion inhibition. © 2006 Elsevier B.V. All rights reserved

Neutrophil extracellular trap (NET) levels in human plasma are associated with active TB

<div><p>Neutrophils are increasingly associated with tuberculosis (TB) disease. Neutrophil extracellular traps (NETs), which are released by neutrophils as a host antimicrobial defense mechanism, are also associated with tissue damage. However, a link between NET levels and TB disease has not been studied. Here we investigate plasma NETs levels in patients with active pulmonary tuberculosis using an ELISA assay that is suitable for high-throughput processing. We show that plasma NETs levels at baseline correlated with disease severity and decreased with antibiotic therapy. Our study demonstrates the biologic plausibility of measuring NETs in plasma samples from patients with TB.</p></div