Stability of 3D Cubic Fixed Point in Two-Coupling-Constant \phi^4-Theory

For an anisotropic euclidean $\phi^4$-theory with two interactions [u (\sum_{i=1^M {\phi}_i^2)^2+v \sum_{i=1}^M \phi_i^4] the $\beta$-functions are calculated from five-loop perturbation expansions in $d=4-\varepsilon$ dimensions, using the knowledge of the large-order behavior and Borel transformations. For $\varepsilon=1$, an infrared stable cubic fixed point for $M \geq 3$ is found, implying that the critical exponents in the magnetic phase transition of real crystals are of the cubic universality class. There were previous indications of the stability based either on lower-loop expansions or on less reliable Pad\'{e approximations, but only the evidence presented in this work seems to be sufficently convincing to draw this conclusion.Comment: Author Information under http://www.physik.fu-berlin.de/~kleinert/institution.html . Paper also at http://www.physik.fu-berlin.de/~kleinert/kleiner_re250/preprint.htm

Duality between Topologically Massive and Self-Dual models

We show that, with the help of a general BRST symmetry, different theories in 3 dimensions can be connected through a fundamental topological field theory related to the classical limit of the Chern-Simons model.Comment: 13 pages, LaTe

Actualités sur les co-infections VIH–VHC

Objectives To evaluate the incidence of HIV–HCV co-infections and analyse the outcome in co-infected patients. Epidemiology. Effects of antivirals The prevalence of the co-infection by the HCV thus varies from 10 to 14% on subjects who have sexual behaviors at risk at 80 or 90% on users of drug IV. Numerous studies showed that the infection by the HIV made worse the natural history of the infection by the HCV [J Acquir Immune Defic Syndr 6 1993 602–610; J Hepatol 28 1998 945–950]. On the other hand, the studies which endeavoured to appreciate the effect of the antiretroviral therapeutics on the natural history of the chronic hepatitis C, on the co-infected patients, are more discussed. In cohorts of big size, it was demonstrated that the hepatic mortality increased with the exposure to antiretrovirals. However, the duration of the antiretroviral treatment also reports the more important survival of the patients, which distorts credibly the figures. The effect of the infection by the HCV on the progress of the disease with HIV is more discussed. The patients infected by the HIV, in any case, have to benefit from the research for a co-infection by the viruses of hepatitis B and C (HBV and HCV). This screening must be renewed every year, in particular on the drug addicts patients or presenting behaviors at risk. Viral replication The research of a viral replication, must be implemented for any confirmed positive HCV serology. The research of the HCV RNA needs ultrasensitive techniques of molecular biology which allow a qualitative detection andor a quantification of the viral genome (viral load). The techniques of last generation of real-time PCR combine both approaches (detection and quantification). The viral load HCV is not correlated to the degree of hepatic disease and does not predict the severity of the hepatic disease, contrary to the correlation demonstrated in the infection by the HIV. On the other hand, it can be a predictive factor in the response to the treatment. The pretherapeutic check-up also includes a determination of the viral genotype because a strong involvement in the response to the treatment was clearly demonstrated. Hepatic fibrosis The hepatic fibrosis must be estimated on patients having a chronic hepatitis because it conditions the prognosis and the treatment of the hepatitis. The anatomopathological study after hepatic biopsy (DHB) remains the reference method. Recently, the development of non invasive methods of measure of the hepatic fibrosis improved the care of hepatitis C, notably the blood tests (fibrotest BioPredictive Paris, fibrometer BLS Angers) and physical measures as the impulsional elastometry (Fibroscan® Echosens) which substitutes more and more in practice to the draining hepatic biopsy. Treatment Numerous studies now validated the treatment associating interferon pegilated and ribavirine as the reference treatment on the co-infected patients HIV/HCV. This treatment involves a high virological response going from 14 to 36% in the patients infected by a genotype 1 and 2 and from 43 to 73% in the patients infected by a genotype 2 or 3. The duration of the treatment is 48 weeks. As well as usual virological factors on the mono-infected patients (genotype, viral load), the rate of CD4 is one of the best predictive factors with a good response. Many hopes go towards the new molecules in development (inhibitors of protease), inhibitors of polymerase), with promising results on the mono-infected patients. However, the toxicity of these molecules is not very well known at the moment in the co-infected patients. It is thus necessary to perform trials in this group of patient, by watching very carefully the toxicity of the therapeutic associations

Quasispecies evolution in NS5A region of hepatitis C virus genotype 1b during interferon or combined interferon-ribavirin therapy

AIM: To evaluate the implication of substitutions in the hepatitis C virus (HCV) non-structural 5A (NS5A) protein in the resistance of HCV during mono-interferon (IFN) or combined IFN-ribavirin (IFN-R) therapy. Although NS5A has been reported to interact with the HCV RNA-dependent RNA polymerase, NS5B, as well as with many cellular proteins, the function of NS5A in the life cycle of HCV remains unclear. METHODS: HCV quasispecies were studied by cloning and sequencing of sequential isolates from patients infected by HCV genotype 1b. Patients were treated by IFN-alpha2b for 3 mo followed by IFN-alpha2b alone or combined IFN-R therapy for 9 additional months. Patients were categorized into two groups based on their response to the treatments: 7 with sustained virological response (SVR) (quasispecies = 150) and 3 non-responders (NR) to IFN-R (quasispecies = 106). RESULTS: Prior to treatment, SVR patients displayed a lower complexity of quasispecies than NR patients. Most patients had a decrease in the complexity of quasispecies during therapy. Analysis of amino acids substitutions showed that the degree of the complexity of the interferon sensitivity-determining region (ISDR) and the V3 domain of NS5A protein was able to discriminate the two groups of patients. Moreover, SVR patients displayed more variability in the NS5A region than NR patients. CONCLUSION: These results suggest that detailed molecular analysis of the NS5A region may be important for understanding its function in IFN response during HCV 1b infection

Correlation between the promoter basal core and precore mutations and HBsAg quantification in French blood donors infected with hepatitis B virus

International audienceHepatitis B virus (HBV) basal core promoter (BCP) and precore (PC) mutations, HBV viral load and HBV surface antigen (HBsAg) quantitation were screened to assess correlations between these HBV markers in asymptomatic chronic hepatitis B carriers in France. From January 2006 to July 2007, 200 sera were collected from patients who were discovered to be HBsAg-positive when they volunteered to give blood. Direct sequencing of precore/core gene was used to detect A1762T/G1764A mutations in the BCP and G1896A in the PC region. HBV viral load and HBsAg were quantified with two commercials assays. The prevalence of the BCP and PC mixed/mutants were 37% and 60% respectively (P = 0.0001). HBV DNA level and HBsAg titer were significantly lower in subjects harboring the mixed/mutant PC virus compared to those infected by the wild phenotype. No significant difference was observed in HBV viral loads of blood donors infected by wild or mixed/mutant BCP viruses. Mutant or mixed PC virus was associated with male gender, HBeAb-positive status and HBV/D and HBV/E genotypes. BCP mutations were associated with age, and both HBV/A-HBV/E genotypes.The genetic properties of HBV in this cohort showed that most of the blood donors had a negative HBeAg serological status and harbored the PC mutant phenotype in combination with low levels of both HBV DNA and HBsAg. As the study was conducted in healthy subjects who could be considered as asmptomatic carriers, these results suggest a possible protective effect of the G1896A mutation against severe liver lesions. J. Med. Virol. 87:529–535, 2015. © 2014 Wiley Periodicals, Inc

The DICE calibration project: design, characterization, and first results

We describe the design, operation, and first results of a photometric calibration project, called DICE (Direct Illumination Calibration Experiment), aiming at achieving precise instrumental calibration of optical telescopes. The heart of DICE is an illumination device composed of 24 narrow-spectrum, high-intensity, light-emitting diodes (LED) chosen to cover the ultraviolet-to-near-infrared spectral range. It implements a point-like source placed at a finite distance from the telescope entrance pupil, yielding a flat field illumination that covers the entire field of view of the imager. The purpose of this system is to perform a lightweight routine monitoring of the imager passbands with a precision better than 5 per-mil on the relative passband normalisations and about 3{\AA} on the filter cutoff positions. The light source is calibrated on a spectrophotometric bench. As our fundamental metrology standard, we use a photodiode calibrated at NIST. The radiant intensity of each beam is mapped, and spectra are measured for each LED. All measurements are conducted at temperatures ranging from 0{\deg}C to 25{\deg}C in order to study the temperature dependence of the system. The photometric and spectroscopic measurements are combined into a model that predicts the spectral intensity of the source as a function of temperature. We find that the calibration beams are stable at the $10^{-4}$ level -- after taking the slight temperature dependence of the LED emission properties into account. We show that the spectral intensity of the source can be characterised with a precision of 3{\AA} in wavelength. In flux, we reach an accuracy of about 0.2-0.5% depending on how we understand the off-diagonal terms of the error budget affecting the calibration of the NIST photodiode. With a routine 60-mn calibration program, the apparatus is able to constrain the passbands at the targeted precision levels.Comment: 25 pages, 27 figures, accepted for publication in A&

Detection and quantification of serum or plasma HCV RNA: mini review of commercially available assays

The treatment schedule (combination of compounds, doses, and duration) and the virological follow-up for management of antiviral treatment in patients chronically infected by HCV is now well standardized, but to ensure good monitoring of the treated patients, physicians need rapid, reproducible, and sensitive molecular virological tools with a wide range of detection and quantification of HCV RNA in blood samples. Several assays for detection and/or quantification of HCV RNA are currently commercially available. Here, all these assays are detailed, and a brief description of each step of the assay is provided. They are divided into two categories by method: those based on signal amplification and those based on target amplification. These two categories are then divided into qualitative, quantitative, and quantitative detection assays. The real-time reverse-transcription polymerase chain reaction (RT-PCR)-based assays are the most promising strategy in the HCV virological area