30 research outputs found
Open/closed duality for FZZT branes in c=1
We describe how the matrix integral of Imbimbo and Mukhi arises from a limit
of the FZZT partition function in the double-scaled c=1 matrix model. We show a
similar result for 0A and comment on subtleties in 0B.Comment: 26 pages, 2 figure
Notes on the algebraic curves in (p,q) minimal string theory
Loop amplitudes in (p,q) minimal string theory are studied in terms of the
continuum string field theory based on the free fermion realization of the KP
hierarchy. We derive the Schwinger-Dyson equations for FZZT disk amplitudes
directly from the W_{1+\infty} constraints in the string field formulation and
give explicitly the algebraic curves of disk amplitudes for general
backgrounds. We further give annulus amplitudes of FZZT-FZZT, FZZT-ZZ and ZZ-ZZ
branes, generalizing our previous D-instanton calculus from the minimal unitary
series (p,p+1) to general (p,q) series. We also give a detailed explanation on
the equivalence between the Douglas equation and the string field theory based
on the KP hierarchy under the W_{1+\infty} constraints.Comment: 61 pages, 1 figure, section 2.5 and Appendix B added, references
added, final version to appear in JHE
Minimal Superstrings and Loop Gas Models
We reformulate the matrix models of minimal superstrings as loop gas models
on random surfaces. In the continuum limit, this leads to the identification of
minimal superstrings with certain bosonic string theories, to all orders in the
genus expansion. RR vertex operators arise as operators in a Z_2 twisted sector
of the matter CFT. We show how the loop gas model implements the sum over spin
structures expected from the continuum RNS formulation. Open string boundary
conditions are also more transparent in this language.Comment: 36 pages, 3 figure
In vitro evaluation of transdermal nicotine delivery systems commercially available in Brazil
The aim of this study was to develop and validate a method for evaluating the release and skin permeation from transdermal nicotine patches using the vertical diffusion cell (VDC). The VDC is an experimental apparatus employed in research, development, and the pharmaceutical field because it can simulate conditions closest to those established in clinical trials. Two transdermal nicotine delivery systems marketed in Brazil to release 14 mg over 24 hours were evaluated. Release studies were carried out using a regenerated cellulose dialysis membrane and permeation studies were carried out using excised porcine ear skin. The results indicated that nicotine release from both evaluated patches follows Higuchi's release kinetics, while skin permeation studies indicated zero-order release kinetics. Nicotine release rates were different between both evaluated patches, but drug permeation rates were not significantly different. According to validation studies, the method was appropriate for evaluating in vitro performance of nicotine patches. The proposed method can be applied to in vitro comparative studies between different commercial nicotine patches and may be used as an auxiliary tool in the design of new transdermal nicotine delivery systems
Factors Associated with Revision Surgery after Internal Fixation of Hip Fractures
Background: Femoral neck fractures are associated with high rates of revision surgery after management with internal fixation. Using data from the Fixation using Alternative Implants for the Treatment of Hip fractures (FAITH) trial evaluating methods of internal fixation in patients with femoral neck fractures, we investigated associations between baseline and surgical factors and the need for revision surgery to promote healing, relieve pain, treat infection or improve function over 24 months postsurgery. Additionally, we investigated factors associated with (1) hardware removal and (2) implant exchange from cancellous screws (CS) or sliding hip screw (SHS) to total hip arthroplasty, hemiarthroplasty, or another internal fixation device. Methods: We identified 15 potential factors a priori that may be associated with revision surgery, 7 with hardware removal, and 14 with implant exchange. We used multivariable Cox proportional hazards analyses in our investigation. Results: Factors associated with increased risk of revision surgery included: female sex, [hazard ratio (HR) 1.79, 95% confidence interval (CI) 1.25-2.50; P = 0.001], higher body mass index (fo
Long-term radiological and histological outcomes following selective internal radiation therapy to liver metastases from breast cancer
Contains fulltext :
200234.pdf (publisher's version ) (Open Access)Liver metastasis from breast cancer is associated with poor prognosis and is a major cause of early morbidity and mortality. When liver resection is not feasible, minimally invasive directed therapies are considered to attempt to prolong survival. Selective internal radiation therapy (SIRT) with yttrium-90 microspheres is a liver-directed therapy that can improve local control of liver metastases from colorectal cancer. We present a case of a patient with a ductal breast adenocarcinoma, who developed liver and bone metastasis despite extensive treatment with systemic chemotherapies. Following SIRT to the liver, after an initial response, the patient ultimately progressed in the liver after 7 months. Liver tumor histology obtained 20 months after the SIRT intervention demonstrated the presence of the resin microspheres in situ. This case report demonstrates the long-term control that may be achieved with SIRT to treat liver metastases from breast cancer that is refractory to previous chemotherapies, and the presence of microspheres in situ long-term
Routing and Wavelength Assignment in Generalized WDM Tree Networks of Bounded Degree
The increasing popularity of all-optical networks has led to extensive research on the routing and wavelength assignment problem, also termed as the Routing and Path Coloring problem (RPC). Here we present a polynomial time algorithm that solves RPC exactly in generalized tree networks of bounded degree. This new topology is of practical interest since it models tree-like backbone networks connecting boundedsize LANs of any form. Tree-like backbone structure is very common in practice and bounded size LANs is a reasonable assumption, since LANs are by nature networks unable to sustain a large number of hosts