Elastography in Chronic Liver Diseases

Elastography is useful for diagnosing and grading hepatic fibrosis in patients with chronic liver diseases (CLD). In addition, it may be used as a noninvasive tool for surveillance and prognostication of patients with complications related to CLD. Elastography uses real-time ultrasound to assess for tissue elasticity and is a fast, simple, reproducible, and reliable method for noninvasive liver fibrosis evaluation. Management of chronic liver disease is dependent on the grade of liver fibrosis to ascertain the urgency and choice of treatment and advice on further screening for cirrhosis and hepatocellular carcinoma. This chapter will highlight the role of elastography in the evaluation of chronic liver disease including hepatitis B and C and HIV-related liver disease and nonalcoholic fatty liver disease (NAFLD)

Towards analytic description of a transition from weak to strong coupling regime in correlated electron systems. I. Systematic diagrammatic theory with two-particle Green functions

We analyze behavior of correlated electrons described by Hubbard-like models at intermediate and strong coupling. We show that with increasing interaction a pole in a generic two-particle Green function is approached. The pole signals metal-insulator transition at half filling and gives rise to a new vanishing ``Kondo'' scale causing breakdown of weak-coupling perturbation theory. To describe the critical behavior at the metal-insulator transition a novel, self-consistent diagrammatic technique with two-particle Green functions is developed. The theory is based on the linked-cluster expansion for the thermodynamic potential with electron-electron interaction as propagator. Parquet diagrams with a generating functional are derived. Numerical instabilities due to the metal-insulator transition are demonstrated on simplifications of the parquet algebra with ring and ladder series only. A stable numerical solution in the critical region is reached by factorization of singular terms via a low-frequency expansion in the vertex function. We stress the necessity for dynamical vertex renormalizations, missing in the simple approximations, in order to describe the critical, strong-coupling behavior correctly. We propose a simplification of the full parquet approximation by keeping only most divergent terms in the asymptotic strong-coupling region. A qualitatively new, feasible approximation suitable for the description of a transition from weak to strong coupling is obtained.Comment: 17 pages, 4 figures, REVTe

Arctic sea-ice melt in 2008 and the role of solar heating

There has been a marked decline in the summer extent of Arctic sea ice over the past few decades. Data from autonomous ice mass-balance buoys can enhance our understanding of this decline. These buoys monitor changes in snow deposition and ablation, ice growth, and ice surface and bottom melt. Results from the summer of 2008 showed considerable large-scale spatial variability in the amount of surface and bottom melt. Small amounts of melting were observed north of Greenland, while melting in the southern Beaufort Sea was quite large. Comparison of net solar heat input to the ice and heat required for surface ablation showed only modest correlation. However, there was a strong correlation between solar heat input to the ocean and bottom melting. As the ice concentration in the Beaufort Sea region decreased, there was an increase in solar heat to the ocean and an increase in bottom melting

Patient Associated Factors that Affect Adherence to Warfarin Therapy in a Tertiary Referral Hospital in Kenya

Warfarin is the most widely used oral anticoagulant but non-adherence to its therapy contributes significantly to sub-optimal anticoagulation control. A crosssectional study was carried out among 147 adult outpatients at Kenyatta National Hospital to determine the level of adherence and explore the associated factors. Adherence was associated with age, gender heart valve surgery, alcohol consumption, and cost of treatment. On multivariate analysis, the independent variables associated with adequate adherence were age (OR = 0.429, 95% CI = 0.228-0.808; p = 0.009), gender (OR = 0.299, 95% CI = 0.123-0.728; p = 0.008) and the type of thromboembolic disease (OR = 0.385, 95% CI = 0.214-0.690; p = 0.001). Adherence was better among females, older age groups and patients who had undergone heart valve surgery. Adherence was poorer among males, younger participants and patients with venous thromboembolism. We suggest that medication adherence counseling to warfarin therapy should be emphasized in poor-adherent patient populations.Key words: Warfarin, adherence, patient factors, Keny

Using unique ORFan genes as strain-specific identifiers for Escherichia coli

Background Bacterial identification at the strain level is a much-needed, but arduous and challenging task. This study aimed to develop a method for identifying and differentiating individual strains among multiple strains of the same bacterial species. The set used for testing the method consisted of 17 Escherichia coli strains picked from a collection of strains isolated in Germany, Spain, the United Kingdom and Vietnam from humans, cattle, swine, wild boars, and chickens. We targeted unique or rare ORFan genes to address the problem of selective and specific strain identification. These ORFan genes, exclusive to each strain, served as templates for developing strain-specific primers. Results Most of the experimental strains (14 out of 17) possessed unique ORFan genes that were used to develop strain-specific primers. The remaining three strains were identified by combining a PCR for a rare gene with a selection step for isolating the experimental strains. Multiplex PCR allowed the successful identification of the strains both in vitro in spiked faecal material in addition to in vivo after experimental infections of pigs and recovery of bacteria from faecal material. In addition, primers for qPCR were also developed and quantitative readout from faecal samples after experimental infection was also possible. Conclusions The method described in this manuscript using strain-specific unique genes to identify single strains in a mixture of strains proved itself efficient and reliable in detecting and following individual strains both in vitro and in vivo, representing a fast and inexpensive alternative to more costly methods.Peer Reviewe

Dynamical correlations in multiorbital Hubbard models: Fluctuation-exchange approximations

We study the two band degenerate Hubbard model using the Fluctuation Exchange approximation (FLEX) method and compare the results with Quantum Monte-Carlo calculations. Both the self-consistent and the non-self-consistent versions of the FLEX scheme are investigated. We find that, contrary to the one band case, in the multiband case, good agreement with the Quantum Monte-Carlo results is obtained within the electron-electron T-matrix approximation using the full renormalization of the one-particle propagators. The crossover to strong coupling and the formation of satellites is more clearly visible in the non-self-consistent scheme. Finally we discuss the behavior of the FLEX for higher orbital degeneracy.Comment: 18 pages with 12 PS figure

Reduction of fertility in female rabbits and mice actively immunized with a germ cell antigen (GA-1) from the rabbit

Female rabbits and mice were actively immunized against germ cell antigen (GA-1) of 63 kDa molecular mass isolated from rabbit sperm and testis. There was a significant (P P < 0.01) reduction in fertility as seen by mean 7-9 day implants+/-S.D. per mated mouse actively immunized with GA-1 whether through the intraperitoneal route (GA-1, 1.2+/-1.6; controls, 8.0+/-3.4) or through the subcutaneous/intramuscular route (GA-1, 3.8+/-3.4; controls, 10.1+/-3.9). The antisera from these actively immunized animals were negative for sperm agglutinating and immobilizing antibodies. In the Western blot enzyme-immunobinding procedure, the antisera showed specific binding to a single protein of 63 kDa. The incidence of fertilization of eggs recovered from rabbits inseminated with anti-GA-1 antibodies-treated sperm was not significantly different from control rabbits. The percentage of fertilized eggs obtained from rabbits inseminated with anti-GA-1 antibodies-treated sperm that reached the blastocyst stage upon in vitro incubation, however, was significantly less than that for embryos obtained from rabbits inseminated with control serum-treated sperm. Incubation of normal fertilized eggs in vitro with the antibodies did not affect development. Neither antiserum nor immune uterine fluid reacted with 4-day blastocysts in the indirect immunofluorescence technique. It is concluded that active immunization with GA-1 results in post-fertilization reduction of fertility in rabbits and mice by inhibiting early embryonic development.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/25986/1/0000052.pd

Vertex-corrected perturbation theory for the electron-phonon problem with non-constant density of states

A series of weak-coupling perturbation theories which include the lowest-order vertex corrections are applied to the attractive Holstein model in infinite dimensions. The approximations are chosen to reproduce the iterated perturbation theory in the limit of half-filling and large phonon frequency (where the Holstein model maps onto the Hubbard model). Comparison is made with quantum Monte Carlo solutions to test the accuracy of different approximation schemes.Comment: 31 pages, 15 figures, typeset in ReVTe

Surface freshening in the Arctic Ocean's Eurasian Basin : an apparent consequence of recent change in the wind-driven circulation

Author Posting. © American Geophysical Union, 2011. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Journal of Geophysical Research 116 (2011): C00D03, doi:10.1029/2011JC006975.Data collected by an autonomous ice-based observatory that drifted into the Eurasian Basin between April and November 2010 indicate that the upper ocean was appreciably fresher than in 2007 and 2008. Sea ice and snowmelt over the course of the 2010 drift amounted to an input of less than 0.5 m of liquid freshwater to the ocean (comparable to the freshening by melting estimated for those previous years), while the observed change in upper-ocean salinity over the melt period implies a freshwater gain of about 0.7 m. Results of a wind-driven ocean model corroborate the observations of freshening and suggest that unusually fresh surface waters observed in parts of the Eurasian Basin in 2010 may have been due to the spreading of anomalously fresh water previously residing in the Beaufort Gyre. This flux is likely associated with a 2009 shift in the large-scale atmospheric circulation to a significant reduction in strength of the anticyclonic Beaufort Gyre and the Transpolar Drift Stream.This work was funded by the National Science Foundation Office of Polar Programs Arctic Sciences Section under awards ARC‐0519899, ARC‐0856479, and ARC‐ 0806306