738 research outputs found
Plasma von Willebrand factor levels predict in-hospital survival in patients with acute-on-chronic liver failure
BACKGROUND AND AIMS: Circulating levels of von Willebrand factor (vWF) predict mortality in patients with cirrhosis. We hypothesized that systemic inflammation in acute-on-chronic liver failure (ACLF) will stimulate endothelium, increase vWF levels, and promote platelet microthrombi causing organ failure. METHODS: In this prospective study, we correlated plasma vWF levels with organ failure, liver disease severity, sepsis, and systemic inflammatory response syndrome (SIRS) and also analyzed if vWF levels predicted in-hospital composite poor outcome (i.e. death/discharged in terminal condition/liver transplantation) in consecutive ACLF patients. RESULTS: Twenty-one of the 50 ACLF patients studied had composite poor outcome. ACLF patients had markedly elevated vWF antigen and activity (sevenfold and fivefold median increase, respectively) on days 1 and 3. Median ratio of vWF to a disintegrin and metalloprotease with thrombospondin type 1 motif, member 13 (ADAMTS13) activity on day 1 was significantly higher in ACLF patients (11.2) compared to 20 compensated cirrhosis patients (3.3) and healthy volunteers (0.9). On day 1, area under ROC curve (AUROC) to predict composite poor outcome of hospital stay for ACLF patients for vWF antigen, vWF activity, and model for end-stage liver disease (MELD) score were 0.63, 0.68, and 0.74, respectively. vWF activity correlated better with liver disease severity (MELD score, ACLF grade) and organ failure (Sequential Organ Failure Assessment [SOFA] score) than vWF antigen; in contrast, neither vWF antigen nor activity correlated with platelet count, sepsis, or SIRS. CONCLUSIONS: vWF levels are markedly elevated, correlate with organ failure, and predict in-hospital survival in ACLF patients. This data provides a mechanistic basis for postulating that vWF-reducing treatments such as plasma exchange may benefit ACLF patients
Arsenicosis, possibly from contaminated groundwater, associated with noncirrhotic intrahepatic portal hypertension.
BACKGROUND AND AIMS: Idiopathic noncirrhotic intrahepatic portal hypertension (NCIPH), a chronic microangiopathy of the liver caused by arsenicosis from use of contaminated groundwater, was reported from Asia. This study aimed to see, if in the twenty-first century, arsenicosis was present in NCIPH patients at our hospital and, if present, to look for groundwater contamination by arsenic in their residential locality. METHODS: Twenty-seven liver biopsy proven NCIPH patients, 25 portal hypertensive controls with hepatitis B or C related cirrhosis and 25 healthy controls, matched for residential locality, were studied. Eighty-four percent to 96 % of study subjects belonged to middle or lower socioeconomic category. Arsenicosis was looked for by estimation of arsenic levels in finger/toe nails and by skin examination. Arsenic levels in nails and in ground water (in NCIPH patients with arsenicosis) was estimated by mass spectrometry. RESULTS: Nail arsenic levels were raised in five (10 %) portal hypertensive study subjects [two NCIPH patients (both had skin arsenicosis) and three portal hypertensive controls]. All of these five patients were residents of West Bengal or Bangladesh. Skin arsenicosis was noted in three NCIPH patients (11 %) compared to none of disease/healthy controls. Ground water from residential locality of one NCIPH patient with arsenicosis (from Bangladesh) showed extremely high level of arsenic (79.5 μg/L). CONCLUSIONS: Arsenicosis and microangiopathy of liver, possibly caused by environmental contamination continues in parts of Asia. Further studies are needed to understand the mechanisms of such 'poverty-linked thrombophilia'
On the Existence of Meta-stable Vacua in Klebanov-Strassler
We solve for the complete space of linearized deformations of the
Klebanov-Strassler background consistent with the symmetries preserved by a
stack of anti-D3 branes smeared on the of the deformed conifold. We find
that the only solution whose UV physics is consistent with that of a
perturbation produced by anti-D3 branes must have a singularity in the
infrared, coming from NS and RR three-form field strengths whose energy density
diverges. If this singularity is admissible, our solution describes the
backreaction of the anti-D3 branes, and is thus likely to be dual to the
conjectured metastable vacuum in the Klebanov-Strassler field theory. If this
singularity is not admissible, then our analysis strongly suggests that anti-D3
branes do not give rise to metastable Klebanov-Strassler vacua, which would
have dramatic consequences for some string theory constructions of de Sitter
space. Key to this result is a simple, universal form for the force on a probe
D3-brane in our ansatz.Comment: 35 pages, LaTeX. v2: further details provided regarding the IR
singularity and the discussion modified accordingly. typos corrected, refs
adde
Large N Free Energy of 3d N=4 SCFTs and AdS/CFT
We provide a non-trivial check of the AdS_4/CFT_3 correspondence recently
proposed in arXiv:1106.4253 by verifying the GKPW relation in the large N
limit. The CFT free energy is obtained from the previous works
(arXiv:1105.2551, arXiv:1105.4390) on the S^3 partition function for
3-dimensional N=4 SCFT T[SU(N)]. This is matched with the computation of the
type IIB action on the corresponding gravity background. We unexpectedly find
that the leading behavior of the free energy at large N is 1/2 N^2 ln N. We
also extend our results to richer theories and argue that 1/2 N^2 ln N is the
maximal free energy at large N in this class of gauge theories.Comment: 20 pages, 3 figure
AdS Black Hole Solutions in the Extended New Massive Gravity
We have obtained (warped) AdS black hole solutions in the three dimensional
extended new massive gravity. We investigate some properties of black holes and
obtain central charges of the two dimensional dual CFT. To obtain the central
charges, we use the relation between entropy and temperature according to the
AdS/CFT dictionary. For AdS black holes, one can also use the central charge
function formalism which leads to the same results.Comment: 24pages, some organization corrected, minor corrections, references
added, final published versio
Pseudomoduli Dark Matter and Quiver Gauge Theories
We investigate supersymmetric models for dark matter which is represented by
pseudomoduli in weakly coupled hidden sectors. We propose a scheme to add a
dark matter sector to quiver gauge theories with metastable supersymmetry
breaking. We discuss the embedding of such scheme in string theory and we
describe the dark matter sector in terms of D7 flavour branes. We explore the
phenomenology in various regions of the parameters.Comment: 24 pages, 12 figures, JHEP3.cl
Aging Logarithmic Conformal Field Theory : a holographic view
We consider logarithmic extensions of the correlation and response functions
of scalar operators for the systems with aging as well as Schr\"odinger
symmetry. Aging is known to be the simplest nonequilibrium phenomena, and its
physical significances can be understood by the two-time correlation and
response functions. Their logarithmic part is completely fixed by the bulk
geometry in terms of the conformal weight of the dual operator and the dual
particle number.
Motivated by recent experimental realizations of Kardar-Parisi-Zhang
universality class in growth phenomena and its subsequent theoretical extension
to aging, we investigate our two-time correlation functions out of equilibrium,
which show several qualitatively different behaviors depending on the
parameters in our theory. They exhibit either growing or aging, i.e. power-law
decaying, behaviors for the entire range of our scaling time. Surprisingly, for
some parameter ranges, they exhibit growing at early times as well as aging at
later times.Comment: 1+26 pages, 15 figure
Thresholds of large N factorization in CFT4: exploring bulk spacetime in AdS(5)
52 pages, 6 figures52 pages, 6 figure
Holographic Renormalization and Stress Tensors in New Massive Gravity
We obtain holographically renormalized boundary stress tensors with the
emphasis on a special point in the parameter space of three dimensional new
massive gravity, using the so-called Fefferman-Graham coordinates with relevant
counter terms. Through the linearized equations of motion with a standard
prescription, we also obtain correlators among these stress tensors. We argue
that the self-consistency of holographic renormalization determines counter
terms up to unphysical ambiguities. Using these renormalized stress tensors in
Fefferman-Graham coordinates, we obtain the central charges of dual CFT, and
mass and angular momentum of some black hole solutions. These results are
consistent with the previous ones obtained by other methods. In this study on
the Fefferman-Graham expansion of new massive gravity, some aspects of higher
curvature gravity are revealed.Comment: Version accepted for publication in JHEP, conclusion revised,
references adde
Kerr/CFT, dipole theories and nonrelativistic CFTs
We study solutions of type IIB supergravity which are SL(2,R) x SU(2) x
U(1)^2 invariant deformations of AdS_3 x S^3 x K3 and take the form of products
of self-dual spacelike warped AdS_3 and a deformed three-sphere. One of these
backgrounds has been recently argued to be relevant for a derivation of
Kerr/CFT from string theory, whereas the remaining ones are holographic duals
of two-dimensional dipole theories and their S-duals. We show that each of
these backgrounds is holographically dual to a deformation of the DLCQ of the
D1-D5 CFT by a specific supersymmetric (1,2) operator, which we write down
explicitly in terms of twist operators at the free orbifold point. The
deforming operator is argued to be exactly marginal with respect to the
zero-dimensional nonrelativistic conformal (or Schroedinger) group - which is
simply SL(2,R)_L x U(1)_R. Moreover, in the supergravity limit of large N and
strong coupling, no other single-trace operators are turned on. We thus propose
that the field theory duals to the backgrounds of interest are nonrelativistic
CFTs defined by adding the single Schroedinger-invariant (1,2) operator
mentioned above to the original CFT action. Our analysis indicates that the
rotating extremal black holes we study are best thought of as finite
right-moving temperature (non-supersymmetric) states in the above-defined
supersymmetric nonrelativistic CFT and hints towards a more general connection
between Kerr/CFT and two-dimensional non-relativistic CFTs.Comment: 48+8 pages, 4 figures; minor corrections and references adde
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