18,473 research outputs found
Insulin Solution Stability and Biocompatibility with Materials Used for an Implantable Insulin Delivery Device Using Reverse Phase HPLC Methods
open access articleAbstract: Insulin (Humulin® R IU500) has been delivered from an implantable artificial pancreas in
diabetic rats and pigs. The artificial pancreas which was implanted in the peritoneum was fabricated
from several biocompatible materials such as polycarbonate, stainless steel, polyurethane, titanium
and a polyurethane resin. The device also contains a glucose responsive smart gel which controls the
di usion of insulin dependent on the surrounding glucose environment. As the insulin reservoir is
refillable and in contact with the device materials, assessing its biocompatibility with these various
device component materials was conducted. Insulin can undergo chemical degradation mainly
via a deamidation reaction on glutamine and asparagine residues rendering its biological hormone
functionality. Two Reverse Phase High Performance Liquid Chromatography (RP-HPLC) methods
were developed and validated for detection of insulin and degradant Asn A21 desamido insulin
(method A) and insulin and degradant Asn B3 desamido insulin (method B). Material biocompatibility
studies show that stainless steel and titanium are suitable for an implantable insulin delivery device
design over a 31-day period. The use of polycarbonate and polyurethane could be considered if the
insulin reservoir in the device was only to remain in the device for less than 11 days after which time
there is a loss in cresol which acts in a protective capacity for insulin stability
A Concise Total Synthesis of (--)-Maoecrystal Z
The first total synthesis of (--)-maoecrystal Z
is described. The key steps of the synthesis include a
diastereoselective Ti^(III)-mediated reductive epoxide coupling reaction and a diastereoselective Sm^(II)-mediated reductive cascade cyclization reaction. These transformations enabled the preparation of (--)-maoecrystal Z in only 12 steps from (--)-γ-cyclogeraniol
Coupled Resonator Optical Waveguides: Toward the Slowing and Storage of Light
The development of a simple, solid-state-based technology to slow the propagation of light could prove an important step in the realization of the high-bit-rate communication systems of the future. The use of coupled resonator optical waveguides (CROWs) as practical elements to slow and store light pulses is one possibility
Hyperatlas: A New Framework for Image Federation
Hyperatlas is an open standard intended to facilitate the large-scale
federation of image-based data. The subject of hyperatlas is the space of
sphere-to-plane projection mappings (the FITS-WCS information), and the
standard consists of coherent collections of these on which data can be
resampled and thereby federated with other image data. We hope for a
distributed effort that will produce a multi-faceted image atlas of the sky,
made by federating many different surveys at different wavelengths and
different times. We expect that hyperatlas-compliant imagery will be published
and discovered through an International Virtual Observatory Alliance (IVOA)
registry, and that grid-based services will emerge for the required resampling
and mosaicking.Comment: Published in ADASS XIII proceeding
Atlasmaker: A Grid-based Implementation of the Hyperatlas
The Atlasmaker project is using Grid technology, in combination with NVO
interoperability, to create new knowledge resources in astronomy. The product
is a multi-faceted, multi-dimensional, scientifically trusted image atlas of
the sky, made by federating many different surveys at different wavelengths,
times, resolutions, polarizations, etc. The Atlasmaker software does resampling
and mosaicking of image collections, and is well-suited to operate with the
Hyperatlas standard. Requests can be satisfied via on-demand computations or by
accessing a data cache. Computed data is stored in a distributed virtual file
system, such as the Storage Resource Broker (SRB). We expect these atlases to
be a new and powerful paradigm for knowledge extraction in astronomy, as well
as a magnificent way to build educational resources. The system is being
incorporated into the data analysis pipeline of the Palomar-Quest synoptic
survey, and is being used to generate all-sky atlases from the 2MASS, SDSS, and
DPOSS surveys for joint object detection.Comment: Published in the Proceedings of ADASS XI
Impact of the introduction of commercial purse- seine operations on the traditional fisheries of the Karnataka coast in India
It was during 1977 that large -scale operation of purse – seines started in India mostly along the Karnataka coast. No doubt this has
substantially increased the marine fish landings , especially mackerel and sardines . But it has affected the traditional Rampani fishing which
also exploits the same fishery resources . The paper makes an impact analysis of this development
Thermodynamics of aluminum-barium alloys
The activity of barium in liquid Al-Ba alloys (XBa ≤ 0.261) at 1373 K has been determined using the Knudsen effusion-mass loss technique. At higher concentrations (XBa ≥ 0.38), the activity of barium has been determined by the pseudo-isopiestic technique. Activity of aluminum has been derived by Gibbs-Duhem integration. The concentration-concentration structure factor of Bhatia and Thornton[22] at zero wave vector has been computed from the thermodynamic data. The behavior of the mean-square thermal fluctuation in composition indicates a tendency for association in the liquid state. The associated solution model with Al5Ba4 as the predominant complex has been used for the description of the thermodynamic behavior of liquid Al-Ba alloys. Thermodynamic data for the intermetallic compounds in the Al-Ba system and the enthalpy of mixing in liquid alloys have been derived using the phase diagram and the Gibbs' energy of mixing of liquid alloys
Thermodynamic stability of metallurgical coke relative to graphite
This article does not have an abstract
Using imprecise continuous time Markov chains for assessing the reliability of power networks with common cause failure and non-immediate repair.
We explore how imprecise continuous time Markov
chains can improve traditional reliability models based
on precise continuous time Markov chains. Specifically,
we analyse the reliability of power networks under very
weak statistical assumptions, explicitly accounting for
non-stationary failure and repair rates and the limited
accuracy by which common cause failure rates can be
estimated. Bounds on typical quantities of interest
are derived, namely the expected time spent in system
failure state, as well as the expected number of
transitions to that state. A worked numerical example
demonstrates the theoretical techniques described.
Interestingly, the number of iterations required for
convergence is observed to be much lower than current
theoretical bounds
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