Spontaneous cluster formation in stoichiometric quantum critical systems

Metallic systems with magnetic ions embedded which have been prepared to undergo a second-order phase transition at zero Kelvin (called the quantum critical systems) historically appear to fall into two distinct categories: (chemically) heavilydoped systems in which the unusual properties can be attributed to a disorder-induced distribution of Kondo shielding temperatures, and (nearly) stoichiometric systems where the departures from Fermi-liquid theory have been attributed to intrinsic instabilities. We show that this distinction between doped and stoichiometric systems is no longer a clear-cut boundary and that magnetic clusters associated with a distribution of Kondo shielding temperatures found in the heavily doped quantum critical Ce(Fe0:755Ru0:245)2Ge2 are also present in CeRu2Si2, a stoichiometric system close to a quantum critical point. By revisiting published data on CeRu2Si2 and comparing them to the results of Ce(Fe0:755Ru0:245)2Ge2, we show that clusters consisting of Ce-ions with their moments aligned with their neighbors exist in both systems at low temperatures and dominate the macroscopic response of these systems. We show these clusters form from a distribution of Kondo shielding temperatures which naturally arises from a distribution in inter-ionic separations; the chemical doping of ruthenium in Ce(Fe0:755Ru0:245)2Ge2 and zero-point motion in stoichiometric CeRu2Si2. We show that the dominant physics which drives heavily-doped systems, namely spontaneous formation of mag netic clusters, also plays a leading role in the response of homogenous systems. We investigate the presence of these spontaneous clusters in the heavily studied YbRh2Si2 where neutron scattering data have not been published. We show that the specific heat and susceptibility are naturally interpreted when ordered magnetic clusters are taken into account. Thus, cluster formation appears to be ubiquitous at the quantum critical point. We end with potential implications of the findings (that small changes in interionic separations ends up dominating the macroscopic response) to another class of highly correlated electron systems: the cuprate high Tc superconductors. We speculate that ionic displacements associated with hole doping leads to a pathway for the formation of Cooper pairs. We show that this pathway leads to an explanation for the many experimental observations, such as the striped phase and the hourglass dispersion.Includes bibliographical references

Microbiota Control of Malaria Transmission

This publication hasn't any creative commons license associated.This deposit is composed by the main article, and it hasn't any supplementary materials associated.The deposited article is a post-print version.Stable mutualistic interactions between multicellular organisms and microbes are an evolutionarily conserved process with a major impact on host physiology and fitness. Humans establish such interactions with a consortium of microorganisms known as the microbiota. Despite the mutualistic nature of these interactions, some bacterial components of the human microbiota express immunogenic glycans that elicit glycan-specific antibody (Ab) responses. The ensuing circulating Abs are protective against infections by pathogens that express those glycans, as demonstrated for Plasmodium, the causative agent of malaria. Presumably, a similar protective Ab response acts against other vector-borne diseases.Bill & Melinda Gates Foundation grant: (OPP1024563); Fundação para a Ciência e Tecnologia grants: (RECI-IMI-IMU-0038-2012; SFRH/BD/51176/2010); European Research Council grant: (ERC-2011-AdG 294709-DAMAGECONTROL).info:eu-repo/semantics/publishedVersio

In Vitro and In Vivo Efficacy of Ether Lipid Edelfosine against Leishmania spp. and SbV-Resistant Parasites

Leishmaniasis represents a major international health problem, has a high morbidity and mortality rate, and is classified as an emerging and uncontrolled disease by the World Health Organization. The migration of population from endemic to nonendemic areas, and tourist activities in endemic regions are spreading the disease to new areas. Unfortunately, treatment of leishmaniasis is far from satisfactory, with only a few drugs available that show significant side-effects. Here, we show in vitro and in vivo evidence for the antileishmanial activity of the ether phospholipid edelfosine, being effective against a wide number of Leishmania spp. causing cutaneous, mucocutaneous and visceral leishmaniasis. Our experimental mouse and hamster models demonstrated not only a significant antileishmanial activity of edelfosine oral administration against different wild-type Leishmania spp., but also against parasites resistant to pentavalent antimonials, which constitute the first line of treatment worldwide. In addition, edelfosine exerted a higher antileishmanial activity and a lower proneness to generate drug resistance than miltefosine, the first drug against leishmaniasis that can be administered orally. These data, together with our previous findings, showing an anti-inflammatory action and a very low toxicity profile, suggest that edelfosine is a promising orally administered drug for leishmaniasis, thus warranting clinical evaluation

Understanding the dynamics of hepatitis C virus transmission in a high-risk environment

HCV is mainly transmitted between people who inject drugs in developed countries. In this population, HCV prevalence is high and incarceration is recognised to be an independent risk factor for infection. This thesis integrates epidemiology, molecular epidemiology, and computational modelling to investigate HCV transmission among inmates in NSW prisons.In the first study, HCV incidence and associated risk behaviours were calculated in a prospective cohort of inmates in NSW prisons. Thirty-eight HCV incident cases were identified in 269.94 person-years of follow-up yielding an estimated HCV incidence of 14.08 (95% CI: 9.96-19.32) per 100 person-years. Indigenous identity, injecting daily or more often, and injecting heroin were found to be associated with an increased risk of HCV infection.The second study integrated virus sequences with risk behaviour and spatio-temporal data in order to reveal transmission clusters among inmates in NSW. Three clusters of recent HCV transmission were detected consisting of four in-custody transmission events involving drug injecting and sharing between source/recipient pairs located in the same prison at the same time. Despite a large background population of prisoners with chronic HCV, transmission events from recently infected individuals were identified in the prison setting. In the third study, a computational model was developed to simulate the ongoing HCV epidemics in the NSW prisons. The model was used to predict future epidemiological trends and investigate scenarios of altered risk affecting the epidemic. The projected incidence of HCV was stable at 9.72 (95% CI: 9.36-10.08) per 100 person-years until 2020. The potential impact of changes in incarceration rates, and HCV prevention strategies to reduce HCV transmission in NSW prisons were explored. This approach of integrated epidemiological, molecular epidemiological and modeling methods to study HCV transmissions has clear capacity to inform policy and public health practice in the prison setting. Future work includes consideration of social network information, assessment of new antiviral treatment strategies in NSW prisons, and enhancing linkage with community-based research