855 research outputs found
Higher Order and boundary Scaling Fields in the Abelian Sandpile Model
The Abelian Sandpile Model (ASM) is a paradigm of self-organized criticality
(SOC) which is related to conformal field theory. The conformal fields
corresponding to some height clusters have been suggested before. Here we
derive the first corrections to such fields, in a field theoretical approach,
when the lattice parameter is non-vanishing and consider them in the presence
of a boundary.Comment: 7 pages, no figure
Spatial Asymmetric Two dimensional Continuous Abelian Sandpile Model
We insert some asymmetries in the continuous Abelian sandpile models, such as
directedness and ellipticity. We analyze probability distribution of different
heights and also find the field theory corresponding to the models. Also we
find the fields associated with some height variables.Comment: 14 Pages, 11 Figure
Abelian Sandpile Model on the Honeycomb Lattice
We check the universality properties of the two-dimensional Abelian sandpile
model by computing some of its properties on the honeycomb lattice. Exact
expressions for unit height correlation functions in presence of boundaries and
for different boundary conditions are derived. Also, we study the statistics of
the boundaries of avalanche waves by using the theory of SLE and suggest that
these curves are conformally invariant and described by SLE2.Comment: 24 pages, 5 figure
Prevention and Reversal of Antibody Responses Against Factor IX in Gene Therapy for Hemophilia B
Intramuscular (IM) administration of an adeno-associated viral (AAV) vector represents a simple and safe method of gene transfer for treatment of the X-linked bleeding disorder hemophilia B (factor IX, F.IX, deficiency). However, the approach is hampered by an increased risk of immune responses against F.IX. Previously, we demonstrated that the drug cocktail of immune suppressants rapamycin, IL-10, and a specific peptide (encoding a dominant CD4+ T cell epitope) caused an induction of regulatory T cells (Treg) with a concomitant apoptosis of antigen-specific effector T cells (Nayak et al., 2009). This protocol was effective in preventing inhibitory antibody formation against human F.IX (hF.IX) in muscle gene transfer to C3H/HeJ hemophilia B mice (with targeted F9 gene deletion). Here, we show that this protocol can also be used to reverse inhibitor formation. IM injection of AAV1–hF.IX vector resulted in inhibitors of on average 8–10 BU within 1 month. Subsequent treatment with the tolerogenic cocktail accomplished a rapid reduction of hF.IX-specific antibodies to <2 BU, which lasted for >4.5 months. Systemic hF.IX expression increased from undetectable to >200 ng/ml, and coagulation times improved. In addition, we developed an alternative prophylactic protocol against inhibitor formation that did not require knowledge of T cell epitopes, consisting of daily oral administration of rapamycin for 1-month combined with frequent, low-dose intravenous injection of hF.IX protein. Experiments in T cell receptor transgenic mice showed that the route and dosing schedule of drug administration substantially affected Treg induction. When combined with intravenous antigen administration, oral delivery of rapamycin had to be performed daily in order to induce Treg, which were suppressive and phenotypically comparable to natural Treg
The Neurological Manifestations of Post-Acute Sequelae of SARS-CoV-2 infection
Purpose of Review: Coronavirus disease 2019 (COVID-19), caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), is a global health challenge. This review aims to summarize the incidence, risk factors, possible pathophysiology, and proposed management of neurological manifestations of post-acute sequelae of SARS-CoV-2 infection (PASC) or neuro-PASC based on the published literature. Recent Findings: The National Institutes of Health has noted that PASC is a multi-organ disorder ranging from mild symptoms to an incapacitating state that can last for weeks or longer following recovery from initial infection with SARS-CoV-2. Various pathophysiological mechanisms have been proposed as the culprit for the development of PASC. These include, but are not limited to, direct or indirect invasion of the virus into the brain, immune dysregulation, hormonal disturbances, elevated cytokine levels due to immune reaction leading to chronic inflammation, direct tissue damage to other organs, and persistent low-grade infection. A multidisciplinary approach for the treatment of neuro-PASC will be required to diagnose and address these symptoms. Tailored rehabilitation and novel cognitive therapy protocols are as important as pharmacological treatments to treat neuro-PASC effectively. Summary: With recognizing the growing numbers of COVID-19 patients suffering from neuro-PASC, there is an urgent need to identify affected individuals early to provide the most appropriate and efficient treatments. Awareness among the general population and health care professionals about PASC is rising, and more efforts are needed to understand and treat this new emerging challenge. In this review, we summarize the relevant scientific literature about neuro-PASC
Family History as a Risk for Upper Gastrointestinal Tract Cancer: A Case Control Study
Abstract Background: Although, family history of cancer is an important risk factor for upper gastrointestinal cancers development, but limited information is available on the upper gastrointestinal cancers associated with family history in Iran. The purpose of this study was to define upper gastrointestinal cancers risk associated with family history of cancer
Degradation versus self-assembly of block copolymer micelles
The stability of micelles self-assembled from block copolymers can be altered
by the degradation of the blocks. Slow degradation shifts the equilibrium size
distribution of block copolymer micelles and change their properties.
Quasi-equilibrium scaling theory shows that the degradation of hydrophobic
blocks in the core of micelles destabilize the micelles reducing their size,
while the degradation of hydrophilic blocks forming coronas of micelles favors
larger micelles and may, at certain conditions, induce the formation of
micelles from individual chains.Comment: Published in Langmuir http://pubs.acs.org/doi/pdf/10.1021/la204625
Synthesis of Fluorine-18 Functionalized Nanoparticles for use as in vivo Molecular Imaging Agents
Nanoparticles containing fluorine-18 were prepared from block copolymers made by ring opening metathesis polymerization (ROMP). Using the fast initiating ruthenium metathesis catalyst (H_2IMes)(pyr)_2(Cl)_2Ru=CHPh, low polydispersity amphiphilic block copolymers were prepared from a cinnamoyl-containing hydrophobic norbornene monomer and a mesyl-terminated PEG-containing hydrophilic norbornene monomer. Self-assembly into micelles and subsequent cross-linking of the micelle cores by light-activated dimerization of the cinnamoyl groups yielded stable nanoparticles. Incorporation of fluorine-18 was achieved by nucleophilic displacement of the mesylates by the radioactive fluoride ion with 31% incorporation of radioactivity. The resulting positron-emitting nanoparticles are to be used as in vivo molecular imaging agents for use in tumor imaging
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