Morphology and structure of particles produced by femtosecond laser ablation of fused silica

The aim of the present work was to study the morphology and structure of the nanoparticles produced by femtosecond laser ablation of fused silica. Ultrashort laser pulses of 1030 nm wavelength and 550 fs duration were tightly focused by a high numerical aperture microscope objective at the surface of fused silica samples while scanning the sample in relation to the stationary laser beam. Laser tracks were created with pulse energies in the range 5-100 mu J, resulting in ablation debris of different morphologies. The debris were examined by scanning and transmission electron microscopy for their morphology and crystal structure in relation to the incident laser pulse energy. Ejected particles with sizes ranging from a few nanometers to a few microns were found. Their morphologies can be broadly classified into three categories: very fine round nanoparticles with diameters lower than 20 nm, nanoparticles with intermediate sizes between 50 and 200 nm, and big irregular particles with typical size between 0.5 and 1.5 mu m. The fine nanoparticles of the first category are predominantly observed at higher pulse energies and tend to aggregate to form web-like and arborescent-like structures. The nanoparticles with intermediate sizes are observed for all pulse energies used and may appear isolated or aggregated in clusters. Finally, the larger irregular particles of the third category are observed for all energies and appear normally isolated.

Lymphoepithelioma-like gastric carcinoma presenting as giant ulcer of the lesser curvature. Case report

Lymphoepithelioma-like gastric carcinoma (LELGC) has special clinicopathologic features that differentiate it from the common gastric adenocarcinoma. LELGC is a rare neoplasm of the stomach with an incidence of 1-4% of all gastric cancers and is characterized by desmoplastic stroma uniformaly infiltrated by abundant lymphocytes and plasma cells. LELGC is closely associated with the Epstein-Barr virus (EBV), with 80-100% of LELGC being EBV-positive. LELGC has a male predominance, occurs in elderly people and is usually located in the upper and middle portion of the stomach. We report a rare case of lymphoepithelioma-like gastric carcinoma located in the lesser curvature at the border of the gastric body to the pyloric antrum.

Shape and chemically anisotropic colloidal particles: A theoretical study of their structure, phase behavior, and slow dynamics

A detailed non-equilibrium state diagram of shape-anisotropic particle fluids is constructed. The effects of particle shape are explored using Naive Mode Coupling Theory (NMCT), and a single particle Non-linear Langevin Equation (NLE) theory. The dynamical behavior of non-ergodic fluids are discussed. We employ a rotationally frozen approach to NMCT in order to determine a transition to center of mass (translational) localization. Both ideal and kinetic glass transitions are found to be highly shape dependent, and uniformly increase with particle dimensionality. The glass transition volume fraction of quasi 1- and 2- dimensional particles fall monotonically with the number of sites (aspect ratio), while 3-dimensional particles display a non-monotonic dependence of glassy vitrification on the number of sites. Introducing interparticle attractions results in a far more complex state diagram. The ideal non-ergodic boundary shows a glass-fluid-gel re-entrance previously predicted for spherical particle fluids. The non-ergodic region of the state diagram presents qualitatively different dynamics in different regimes. They are qualified by the different behaviors of the NLE dynamic free energy. The caging dominated, repulsive glass regime is characterized by long localization lengths and barrier locations, dictated by repulsive hard core interactions, while the bonding dominated gel region has short localization lengths (commensurate with the attraction range), and barrier locations. There exists a small region of the state diagram which is qualified by both glassy and gel localization lengths in the dynamic free energy. A much larger (high volume fraction, and high attraction strength) region of phase space is characterized by short gel-like localization lengths, and long barrier locations. The region is called the attractive glass and represents a 2-step relaxation process whereby a particle first breaks attractive physical bonds, and then escapes its topological cage. The dynamic fragility of fluids are highly particle shape dependent. It increases with particle dimensionality and falls with aspect ratio for quasi 1- and 2- dimentional particles. An ultralocal limit analysis of the NLE theory predicts universalities in the behavior of relaxation times, and elastic moduli. The equlibrium phase diagram of chemically anisotropic Janus spheres and Janus rods are calculated employing a mean field Random Phase Approximation. The calculations for Janus rods are corroborated by the full liquid state Reference Interaction Site Model theory. The Janus particles consist of attractive and repulsive regions. Both rods and spheres display rich phase behavior. The phase diagrams of these systems display fluid, macrophase separated, attraction driven microphase separated, repulsion driven microphase separated and crystalline regimes. Macrophase separation is predicted in highly attractive low volume fraction systems. Attraction driven microphase separation is charaterized by long length scale divergences, where the ordering length scale determines the microphase ordered structures. The ordering length scale of repulsion driven microphase separation is determined by the repulsive range. At the high volume fractions, particles forgo the enthalpic considerations of attractions and repulsions to satisfy hard core constraints and maximize vibrational entropy. This results in site length scale ordering in rods, and the sphere length scale ordering in Janus spheres, i.e., crystallization. A change in the Janus balance of both rods and spheres results in quantitative changes in spinodal temperatures and the position of phase boundaries. However, a change in the block sequence of Janus rods causes qualitative changes in the type of microphase ordered state, and induces prominent features (such as the Lifshitz point) in the phase diagrams of these systems. A detailed study of the number of nearest neighbors in Janus rod systems reflect a deep connection between this local measure of structure, and the structure factor which represents the most global measure of order.

Antiviral activity and mechanism of action of arbidol against Hantaan virus infection

Purpose: To investigate the activity and mechanism of action of arbidol against Hantaan virus (HTNV) activity by modulating inflammation via TLR-4 pathway. Methods: HUVEC cells infected with HTNV 76-118 were treated with serially diluted arbidol solutions at -2h (2 h before viral infection, pre-treatment mode), 0 h (at the same time as viral infection, simultaneous treatment mode) or 2 h (2 h after viral infection, post-treatment mode). The transcript levels of TLR4 were detected by semi-quantitative reverse transcription-PCR (RT-PCR) at 6, 12, 18, and 24 h later. The levels of iNOS and TNF-α were examined using enzyme-linked immunosorbent assay (ELISA). Results: Pre-treatment with arbidol, rather than simultaneous treatment or post-treatment, effectively inhibited up-regulation of cellular TLR4 expression (up to 40 ± 6.1 % inhibition) and activity of supernatant iNOS induced by HTNV infection(up to 44.1 ± 9.4 % inhibition), as well as in a LPSstimulated inflammatory endothelial cell. Arbidol decreased the elevated TNF-α levels induced by LPS stimulation. Conclusion: These results are the first evidence that arbidol modulates viral PRRs signaling and its consequential inflammatory cytokine/chemokine response during hantavirus infection.

Étude du niveau de B Lymphocyte Stimulator (BLyS) et de son impact sur les lymphocytes B en relation avec l’infection et la résistance au virus d’immunodéficience humaine (VIH) chez des travailleuses du sexe au Bénin

L’infection au VIH s’accompagne souvent de dérégulations du compartiment des lymphocytes B qui nuisent à la génération de réponses efficaces. En effet, détectées tôt après l’infection, ces dérégulations perdurent, ne sont pas totalement restaurées par la thérapie, et mènent souvent à des manifestations auto-immunes et lymphomes. Une étude longitudinale de notre groupe, effectuée avec des cellules mononucléées du sang circulant provenant de patients VIH+ avec différents types de progression clinique, a démontré qu’un niveau élevé de BLyS chez des individus VIH+ progresseurs était associé à une dérégulation des fréquences de populations de cellules B avec augmentation de cellules innées de la zone marginale (MZ) présentant des caractéristiques d’immaturité et d’activation. Au contraire, chez des individus VIH+ non-progresseurs avirémiques ou contrôleurs d’élite, les niveaux de BLyS étaient dans la normale et ce sont les fréquences de cellules B MZ plus matures qui étaient diminuées. La résistance au VIH pourrait aussi impliquer le contrôle de BLyS et son impact sur les cellules B. De ce fait, nous avons préalablement recruté une cohorte de travailleuses du sexe (TS) à Cotonou (Bénin) dans laquelle nous avons identifié des femmes qui demeurent séronégatives malgré une exposition soutenue au virus. Nous avons mesuré les niveaux de BLyS dans le sang et dans les lavages cervico-vaginaux (CVL) de TS VIH- et les avons comparés à ceux mesurés chez des TS VIH+ et un groupe contrôle de non-TS VIH- . Nous avons trouvé que les niveaux de BLyS dans le sang et le CVL des TS VIH- étaient inférieurs à ceux des TS VIH+ et des non-TS VIH-. Le niveau d’expression de BLyS à la surface des lymphocytes T, monocytes et cellules dendritiques de TS VIH- était augmenté, mais à un niveau moindre que les TS VIH+. Chez les TS VIH+, les hauts niveaux de BLyS étaient concomitants avec une dérégulation du compartiment B caractérisée par une hyperglobulinémie, une augmentation de la fréquence de populations avec un profil immature/inné et une plus grande proportion de plasmablastes IgG vs IgA. Au contraire, les niveaux inférieurs de BLyS dans le sang des TS VIH- coïncident avec un compartiment B préservé, révélant que les lymphocytes B MZ peuvent être impliqués dans l’immunité naturelle au VIH. Ces résultats démontrent l’importance du contrôle des niveaux de BLyS et du maintien de l’intégrité du compartiment B dans la résistance au VIH.

A novel antigen capture ELISA for the specific detection of IgG antibodies to elephant endotheliotropic herpes virus

BACKGROUND Elephants are classified as critically endangered animals by the International Union for Conservation of Species (IUCN). Elephant endotheliotropic herpesvirus (EEHV) poses a large threat to breeding programs of captive Asian elephants by causing fatal haemorrhagic disease. EEHV infection is detected by PCR in samples from both clinically ill and asymptomatic elephants with an active infection, whereas latent carriers can be distinguished exclusively via serological assays. To date, identification of latent carriers has been challenging, since there are no serological assays capable of detecting seropositive elephants. RESULTS Here we describe a novel ELISA that specifically detects EEHV antibodies circulating in Asian elephant plasma/serum. Approximately 80 % of PCR positive elephants display EEHV-specific antibodies. Monitoring three Asian elephant herds from European zoos revealed that the serostatus of elephants within a herd varied from non-detectable to high titers. The antibody titers showed typical herpes-like rise-and-fall patterns in time which occur in all seropositive animals in the herd more or less simultaneously. CONCLUSIONS This study shows that the developed ELISA is suitable to detect antibodies specific to EEHV. It allows study of EEHV seroprevalence in Asian elephants. Results confirm that EEHV prevalence among Asian elephants (whether captive-born or wild-caught) is high.

Étude du niveau de B Lymphocyte Stimulator (BLyS) et de son impact sur les lymphocytes B en relation avec l’infection et la résistance au virus d’immunodéficience humaine (VIH) chez des travailleuses du sexe au Bénin

L’infection au VIH s’accompagne souvent de dérégulations du compartiment des lymphocytes B qui nuisent à la génération de réponses efficaces. En effet, détectées tôt après l’infection, ces dérégulations perdurent, ne sont pas totalement restaurées par la thérapie, et mènent souvent à des manifestations auto-immunes et lymphomes. Une étude longitudinale de notre groupe, effectuée avec des cellules mononucléées du sang circulant provenant de patients VIH+ avec différents types de progression clinique, a démontré qu’un niveau élevé de BLyS chez des individus VIH+ progresseurs était associé à une dérégulation des fréquences de populations de cellules B avec augmentation de cellules innées de la zone marginale (MZ) présentant des caractéristiques d’immaturité et d’activation. Au contraire, chez des individus VIH+ non-progresseurs avirémiques ou contrôleurs d’élite, les niveaux de BLyS étaient dans la normale et ce sont les fréquences de cellules B MZ plus matures qui étaient diminuées. La résistance au VIH pourrait aussi impliquer le contrôle de BLyS et son impact sur les cellules B. De ce fait, nous avons préalablement recruté une cohorte de travailleuses du sexe (TS) à Cotonou (Bénin) dans laquelle nous avons identifié des femmes qui demeurent séronégatives malgré une exposition soutenue au virus. Nous avons mesuré les niveaux de BLyS dans le sang et dans les lavages cervico-vaginaux (CVL) de TS VIH- et les avons comparés à ceux mesurés chez des TS VIH+ et un groupe contrôle de non-TS VIH- . Nous avons trouvé que les niveaux de BLyS dans le sang et le CVL des TS VIH- étaient inférieurs à ceux des TS VIH+ et des non-TS VIH-. Le niveau d’expression de BLyS à la surface des lymphocytes T, monocytes et cellules dendritiques de TS VIH- était augmenté, mais à un niveau moindre que les TS VIH+. Chez les TS VIH+, les hauts niveaux de BLyS étaient concomitants avec une dérégulation du compartiment B caractérisée par une hyperglobulinémie, une augmentation de la fréquence de populations avec un profil immature/inné et une plus grande proportion de plasmablastes IgG vs IgA. Au contraire, les niveaux inférieurs de BLyS dans le sang des TS VIH- coïncident avec un compartiment B préservé, révélant que les lymphocytes B MZ peuvent être impliqués dans l’immunité naturelle au VIH. Ces résultats démontrent l’importance du contrôle des niveaux de BLyS et du maintien de l’intégrité du compartiment B dans la résistance au VIH.

Herpes simplex-like infection in a bottlenose dolphin stranded in the Canary Islands

A bottlenose dolphin, stranded in the Canary Islands in 2001 exhibited non-suppurative encephalitis. No molecular detection of cetacean morbillivirus (CeMV) was found, but a herpesviral-specific band of 250 bp was detected in the lung and brain. The sequenced herpesviral PCR product was compared with GenBank sequences, obtaining 98% homology (p-distance of 0.02) with Human herpesvirus 1 (herpes simplex virus 1 or HSV-1). This is the first report of a herpes simplex-like infection in a stranded dolphin.

Epidemiology and Emergence of Schmallenberg Virus Part 2: Pathogenesis and Risk of Viral Spread

Schmallenberg virus (SBV) is a novel Orthobunyavirus causing mild clinical signs in cows and malformations in aborted and neonatal ruminants in Europe. SBV belongs to the family Bunyaviridae and is transmitted by biting midges. This new virus was identified for the first time in blood samples of cows in the city of Schmallenberg in North-Rhine Westphalia in November 2011. Since then, the virus spread to several European countries. Here, we describe the pathogenesis and the risk of viral spread in the Portuguese territory.

First evidence of Schmallenberg virus introduction in Portugal, 2014

Objectives: Serra da Estrela native (SEN) breed of sheep is one of the most important in Portugal, standing responsible for the production of one of the most internationally recognized cheeses in the world, "Queijo Serra da Estrela” (protected designation of origin). One of the major risks to the sustainability of SEN dairy flocks if footrot, an infectious diseases that causes lameness, decrease in milk production, weight loss and decrease in fertility. The aim of this work was to determine which parameters become decisive for the appearance of footrot in SEN dairy flocks, while establishing associations with environmental and nutritional variables. Materials and Methods: The present study was carried out by performing an especially designed 27 multiple choice questionnaire, based on the underlying causes of lameness in livestock and in the clinical diagnosis performed by the vet techinichian of the clinical cases evaluated at the moment of the inquiry. The survey was performed during the execution of the oficial veterinary health program between February and September of 2014 by a veterinarian team from the Association of SEN Sheep Breeders (ANCOSE). The ovine producers (N=30, with a total of 1270 animals) were randomly selected from the extense area of production of “Queijo Serra da Estrela”. The parameters evaluated in the study were: season and consequent weather changes during the period of the study, floor types, hygiene conditions, bed types, the existence and use of footbaths, location of footbaths, foot trimming and foot hygiene procedures. After the construction of the database and using the Statistical Package for Social Sciences version 16.0 the frequency response for each item was calculated. Results: All SEN livestock producers are proactive in the treatment of lameness (70%). About 99.7% of lameness was related with footroot and most appeared in winter (36.7%). In some occasions there was not a specific season distribution (56.7% rainiest years). From the analyzed farms, 70% use straw as a floor bed, followed by bush (21%). 45.6% of animals were clinically diagnosed with footrot and were sheltered in straw floor. Bed quality is good in 40%, however frequent changes in the floor bed in the preceding 15 days had a higher rate of footroot diagnosed cases (33,23%) compared to monthly changes. Regarding sheepfold animal number, the distribution is proper in 36.7%, elevated in 30%, overcrowded in 6.7% and low in 23.3%. Clinically ill diagnosed animals in last category were the lowest observed (3%). Concerning hoof trimming, 76.7% trims while 23.3% reported not to perform that task. From those that perform trimming, 73.9% do it only when necessary, 21.7% at the time of clipping and 4.4% when the animal is affected. One curious result was that animals who perform trimming at clipping had higher footrot cases (52.6%), unlike those who trim only when necessary (40.2%) or even when animals are clinically ill (0.91%). Mostly all in the presence of footrot choose a local treatment (95.2%) using antibiotic sprays, instead of parenteral antibiotic treatment. Footbath is rarely used in the prevention (13.3%) of this disease and when it is misconceived (25%) and incorrectly formulated (100%). Conclusions: This study was the first performed in Portugal focusing footrot caracterization in native SEN flocks.Economic impact in SEN dairy flocks is atributed to factors such as direct decrease in milk and meat production,early slaughter of affected animals due to non responsive treatment and medical expenses.The most effective eradication method combines first of all the ability to understand the problems of SEN producers and implementation of preventive measures and treatment of footrot.Often linked to lack of formation, the advance age of portuguese producers the mentality and social factors block the advance of veterinarian intervention itself.

2016 Dengue Fever Virus Cases

Dengue fever is the most common cause of fever in travelers returning from the Caribbean, Central America, and South Central Asia.* Dengue infections are commonly reported from most tropical countries of the South Pacific, Asia, the Caribbean, the Americas, and Africa. This disease is caused by four similar viruses (DENV-1, -2, -3, and -4) and is spread through the bites of infected mosquitoes. For information on current outbreaks, consult CDC’s Travelers’ Health website (http://www.cdc.gov/travel). Dengue fever is a severe, flu-like illness that affects infants, young children and adults, but seldom causes death. Dengue should be suspected when a high fever (40°C/104°F) is accompanied by two of the following symptoms: severe headache, pain behind the eyes, muscle and joint pains, nausea, vomiting, swollen glands or rash. Symptoms usually last for 2–7 days, after an incubation period of 4–10 days following the bite from an infected mosquito.

Infección por virus sincitial respiratorio y su relación con valores de IGG en niños críticos

Antecedente: La infección por el virus sincitial respiratorio (VSR) representa una elevada morbimortalidad, y en algunos casos necesidad de manejo en unidades de cuidado intensivo pediátrico (UCIP). La respuesta inmunológica influye de manera directa en la expresión de la severidad y pronóstico de los pacientes con infección respiratoria. Metodología: Estudio de una cohorte retrospectiva de pacientes con infección respiratoria grave secundaria a VSR, sin historia de inmunodeficiencia, atendidos en la UCIP del Hospital Universitario Clínica San Rafael. Se realizó análisis descriptivoglobaly de acuerdo a la categorización de las prueba de IgG. Resultados: De 188 pacientes que ingresaron a la UCIP, 13% presentaron infección por VSR (24), con una edad promedio de 7,3 (DE=3,6) meses. Pertenecían al sexo masculino79,83%. Se encontró que 12,5% tenían un valor de IgGbajo para su edad, 58,33% tenían valores en límite inferior y el 29,17% dentro de rangos normales para su edad. En los pacientes con IgG baja, fue mayor la presentación de choque séptico que no responde a líquidos (100 vs 92 vs 86%), la mediana de días de ventilación mecánica fue mayor (8 vs 6 vs 5 respectivamente), así como la mortalidad (67 vs 7,1 vs 0%). Conclusión: Nuestra serie encontró que aquellos pacientes con niveles bajos o valores en el límite inferior de IgG sérica tuvieron mayor compromiso sistémico, mayor duración de ventilación mecánica y mayor mortalidad. Se necesitan estudios prospectivos que relaciones niveles bajos de IgG con severidad y pronostico en estos pacientes con infección grave por VSR.

Molecular characterization of Grapevine enamolike virus, a novel putative member of the genus Enamovirus.

2016

HIV-1 infection: back and forth between virus and host.

The main obstacles to HIV-1 eradication are linked to the viral ability to evade immune system and establish a reservoir where virus is transcriptionally latent but able to replicate. IFN action and Restriction Factors (RFs) expression, dominant proteins that target multiple steps of the HIV-1 lifecycle, represent an early line of defence Because of their interplay with viral replication, we would like to study the relationship between RFs and the viral amount in latently infected cells.The first part of this project investigates the expression levels variations of a selected group of RFs (APOBEC3G, BST2, TRIM5α, MX2, SAMHD1, SERINC3/5, IFI16 and STING) in HIV-1 patients during the course of infection before and after ART administration by using Real Time qPCR. The second part of this study deals with the role of IFNα and IFNγ, and their role in the immune system disfunction that has been described during chronic inflammation associated to cancer, viral infection such as HIV-1, and autoimmune-disease. Immune Check Point proteins (ICPs) are a group of inhibitory receptors expressed on the cellular surface of immune cells and trigger immunosuppressive signaling pathways leading to T-cell exhaustion and the expression of immune checkpoint molecules (PD-1, PD-L1, TIGIT, LILRB2). The major aim of this project is to assess the clinical meaning of ICPs expression in HIV-1 chronically infected patients to better characterized their involvement in immune system disfunction.

Black hole scattering from Worldline Quantum Field Theory and the Classical Double Copy of Spinning particles

This PhD thesis focuses on studying the classical scattering of massive/massless particles toward black holes, and investigating double copy relations between classical observables in gauge theories and gravity. This is done in the Post-Minkowskian approximation i.e. a perturbative expansion of observables controlled by the gravitational coupling constant κ = 32πGN, with GN being the Newtonian coupling constant. The investigation is performed by using the Worldline Quantum Field Theory (WQFT), displaying a worldline path integral describing the scattering objects and a QFT path integral in the Born approximation, describing the intermediate bosons exchanged in the scattering event by the massive/massless particles. We introduce the WQFT, by deriving a relation between the Kosower- Maybee-O’Connell (KMOC) limit of amplitudes and worldline path integrals, then, we use that to study the classical Compton amplitude and higher point amplitudes. We also present a nice application of our formulation to the case of Hard Thermal Loops (HTL), by explicitly evaluating hard thermal currents in gauge theory and gravity. Next we move to the investigation of the classical double copy (CDC), which is a powerful tool to generate integrands for classical observables related to the binary inspiralling problem in General Relativity. In order to use a Bern-Carrasco-Johansson (BCJ) like prescription, straight at the classical level, one has to identify a double copy (DC) kernel, encoding the locality structure of the classical amplitude. Such kernel is evaluated by using a theory where scalar particles interacts through bi-adjoint scalars. We show here how to push forward the classical double copy so to account for spinning particles, in the framework of the WQFT. Here the quantization procedure on the worldline allows us to fully reconstruct the quantum theory on the gravitational side. Next we investigate how to describe the scattering of massless particles off black holes in the WQFT.