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Encapsulation of water insoluble drugs in mesoporous silica nanoparticles using supercritical carbon dioxide
Mesoporous silica nanoparticles MCM – 41 were synthesized with two dimensional hexagonal p6mm symmetry, high specific surface area(~ 980m2/g) narrow pore size and an average particle size of 186 nm. The produced nanoparticles were used to encapsulate carbamazepine through a supercritical carbon dioxide process combined with various organic solvents. Supercritical processing was found to provide increased drug encapsulation. The loaded MCM - 41 nanoparticles were analyzed using X–ray diffraction and differential scanning calorimetry (DSC) to investigate the crystalline state of the encapsulated carbamazepine and it was found to be dependent on the nature of the organic solvent. Carbamazepine showed increased dissolution rates under sink conditions. Viability studies of Caco – 2 cells demonstrated negligible cytotoxicity for the MCM–41 nanoparticles
Cotransplantation of Adipose Tissue-Derived Insulin-Secreting Mesenchymal Stem Cells and Hematopoietic Stem Cells: A Novel Therapy for Insulin-Dependent Diabetes Mellitus
Aims. Insulin dependent diabetes mellitus (IDDM) is believed to be an autoimmune disorder with disturbed glucose/insulin metabolism, requiring life-long insulin replacement therapy (IRT), 30% of patients develop end-organ failure. We present our experience of cotransplantation of adipose tissue derived insulin-secreting mesenchymal stem cells (IS-AD-MSC) and cultured bone marrow (CBM) as IRT for these patients. Methods. This was a prospective open-labeled clinical trial to test efficacy and safety of IS-AD-MSC+CBM co-transplantation to treat IDDM, approved by the institutional review board after informed consent in 11 (males : females: 7 : 4) patients with 1–24-year disease duration, in age group: 13–43 years, on mean values of exogenous insulin requirement of 1.14 units/kg BW/day, glycosylated hemoglobin (Hb1Ac): 8.47%, and c-peptide levels: 0.1 ng/mL. Intraportal infusion of xenogeneic-free IS-AD-MSC from living donors, subjected to defined culture conditions and phenotypically differentiated to insulin-secreting cells, with mean quantum: 1.5 mL, expressing Pax-6, Isl-1, and pdx-1, cell counts: 2.1 × 103/μL, CD45−/90+/73+:40/30.1%, C-Peptide level:1.8 ng/mL, and insulin level: 339.3 IU/mL with CBM mean quantum: 96.3 mL and cell counts: 28.1 × 103/μL, CD45−/34+:0.62%, was carried out. Results. All were successfully transplanted without any untoward effect. Over mean followup of 23 months, they had a decreased mean exogenous insulin requirement to 0.63 units/kgBW/day, Hb1Ac to 7.39%, raised serum c-peptide levels to 0.38 ng/mL, and became free of diabetic ketoacidosis events with mean 2.5 Kg weight gain on normal vegetarian diet and physical activities. Conclusion. This is the first report of treating IDDM with insulin-secreting-AD-MSC+CBM safely and effectively with relatively simple techniques
Norovirus Infection and Disease in an Ecuadorian Birth Cohort: Association of Certain Norovirus Genotypes With Host FUT2 Secretor Status.
BACKGROUND: Although norovirus is the most common cause of gastroenteritis, there are few data on the community incidence of infection/disease or the patterns of acquired immunity or innate resistance to norovirus. METHODS: We followed a community-based birth cohort of 194 children in Ecuador with the aim to estimate (1) the incidence of norovirus gastroenteritis from birth to age 3 years, (2) the protective effect of norovirus infection against subsequent infection/disease, and (3) the association of infection and disease with FUT2 secretor status. RESULTS: Over the 3-year period, we detected a mean of 2.26 diarrheal episodes per child (range, 0-12 episodes). Norovirus was detected in 260 samples (18%) but was not found more frequently in diarrheal samples (79 of 438 [18%]), compared with diarrhea-free samples (181 of 1016 [18%]; P = .919). A total of 66% of children had at least 1 norovirus infection during the first 3 years of life, and 40% of children had 2 infections. Previous norovirus infections were not associated with the risk of subsequent infection. All genogroup II, genotype 4 (GII.4) infections were among secretor-positive children (P < .001), but higher rates of non-GII.4 infections were found in secretor-negative children (relative risk, 0.56; P = .029). CONCLUSIONS: GII.4 infections were uniquely detected in secretor-positive children, while non-GII.4 infections were more often found in secretor-negative children
Releasing dye encapsulated in proteinaceous microspheres on conductive fabrics by electric current
The current paper reports on the relase properties of conductive fabrics coated with proteinaceous microspheres containing a dye. The release of the dye was achieved by passing an electric current through the fabric. The conductivity of the polyester fibers resulted from nanosilver (Ag NPs) coated on the surface of these fibers. Both types of coatings (nanosilver coating and the coating of the proteinaceous microspheres) were performed using high-intensity ultrasonic waves. Two different types of dyes, hydrophilic RBBR (Remazol Brilliant Blue R) and hydrophobic ORO (Oil Red O), were encapsulated inside the microspheres (attached to the surface of polyester) and then released by applying an electric current. The Proteinaceous Microsphere (PM)-coated conductive fabrics could be used in medicine for drug release. The encapsulated dye can be replaced with a drug that could be released from the surface of fabrics by applying a low voltage
Interacting electrons in disordered potentials: Conductance versus persistent currents
An expression for the conductance of interacting electrons in the diffusive
regime as a function of the ensemble averaged persistent current and the
compressibility of the system is presented. This expression involves only
ground-state properties of the system. The different dependencies of the
conductance and persistent current on the electron-electron interaction
strength becomes apparent. The conductance and persistent current of a small
system of interacting electrons are calculated numerically and their variation
with the strength of the interaction is compared. It is found that while the
persistent current is enhanced by interactions, the conductance is suppressed.Comment: REVTeX, 4 pages, 3 figures, all uuencoded, accepted for publication
in PR
Non-equlibrium effects in transport through quantum dots
The role of non-equilibrium effects in the conductance through quantum dots
is investigated. Associated with single-electron tunneling are shake-up
processes and the formation of excitonic-like resonances. They change
qualitatively the low temperature properties of the system. We analyze by
quantum Monte Carlo methods the renormalization of the effective capacitance
and the gate-voltage dependent conductance. Experimental relevance is
discussed.Comment: 10 pages, 8 postscript figure
Green's Function Monte Carlo for Lattice Fermions: Application to the t-J Model
We develop a general numerical method to study the zero temperature
properties of strongly correlated electron models on large lattices. The
technique, which resembles Green's Function Monte Carlo, projects the ground
state component from a trial wave function with no approximations. We use this
method to determine the phase diagram of the two-dimensional t-J model, using
the Maxwell construction to investigate electronic phase separation. The shell
effects of fermions on finite-sized periodic lattices are minimized by keeping
the number of electrons fixed at a closed-shell configuration and varying the
size of the lattice. Results obtained for various electron numbers
corresponding to different closed-shells indicate that the finite-size effects
in our calculation are small. For any value of interaction strength, we find
that there is always a value of the electron density above which the system can
lower its energy by forming a two-component phase separated state. Our results
are compared with other calculations on the t-J model. We find that the most
accurate results are consistent with phase separation at all interaction
strengths.Comment: 22 pages, 22 figure
Effects of disorder on two strongly correlated coupled chains
We study the effects of disorder on a system of two coupled chain of strongly
correlated fermions (ladder system), using renormalization group. The stability
of the phases of the pure system is investigated as a function of interactions
both for fermions with spin and spinless fermions. For spinless fermions the
repulsive side is strongly localized whereas the system with attractive
interactions is stable with respect to disorder, at variance with the single
chain case. For fermions with spins, the repulsive side is also localized, and
in particular the d-wave superconducting phase found for the pure system is
totally destroyed by an arbitrarily small amount of disorder. On the other hand
the attractive side is again remarkably stable with respect to localization. We
have also computed the charge stiffness, the localization length and the
temperature dependence of the conductivity for the various phases. In the range
of parameter where d-wave superconductivity would occur for the pure system the
conductivity is found to decrease monotonically with temperature, even at high
temperature, and we discuss this surprising result. For a model with one site
repulsion and nearest neighbor attraction, the most stable phase is an orbital
antiferromagnet . Although this phase has no divergent superconducting
fluctuation it can have a divergent conductivity at low temperature. We argue
based on our results that the superconductivity observed in some two chain
compounds cannot be a simple stabilization of the d-wave phase found for a pure
single ladder. Applications to quantum wires are discussed.Comment: 47 pages, ReVTeX , 8 eps figures submitted to PR
de Sitter Vacua in String Theory
We outline the construction of metastable de Sitter vacua of type IIB string
theory. Our starting point is highly warped IIB compactifications with
nontrivial NS and RR three-form fluxes. By incorporating known corrections to
the superpotential from Euclidean D-brane instantons or gaugino condensation,
one can make models with all moduli fixed, yielding a supersymmetric AdS
vacuum. Inclusion of a small number of anti-D3 branes in the resulting warped
geometry allows one to uplift the AdS minimum and make it a metastable de
Sitter ground state. The lifetime of our metastable de Sitter vacua is much
greater than the cosmological timescale of 10^10 years. We also prove, under
certain conditions, that the lifetime of dS space in string theory will always
be shorter than the recurrence time.Comment: 12 pages, 2 figs, added comments on the thin wall approximation to
tunnelin
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