387 research outputs found
Particle characterisation in drug delivery
The use of materials in nano-scale dimensions is proving to be a promising approach to overcome drug delivery challenges. ‘Nanomedicine’ technologies are gradually achieving commercial success and reaching the clinic. Sub-micron nanocarriers have the potential to ferry the therapeutic to its site of action and in this process overcome the biological barriers and achieve targeted drug delivery, controlled or stimuli-responsive delivery and protect the therapeutic from biological milieus. Many different types of nanocarriers have been described, including polymeric nanoparticles (NPs), liposomes, solid lipid NPs, micelles, dendrimers and metal NPs among other systems (the terms ‘nanomedicine’, ‘NP’ and ‘nanocarriers’ are used herein to describe all nanosystems). Of particular interest are nanocarriers with the ability to act selectively and target cell internalisation processes, guiding the therapeutic into subcellular regions. NP features important in dictating their drug delivery performance, including targeted delivery and cellular trafficking, are their size, shape and surface characteristics such as surface charge, chemistry and the distribution of ligands
Study of ground state phases for spin-1/2 Falicov-Kimball model on a triangular lattice
The spin-dependent Falicov-Kimball model (FKM) is studied on a triangular
lattice using numerical diagonalization technique and Monte-Carlo simulation
algorithm. Magnetic properties have been explored for different values of
parameters: on-site Coulomb correlation , exchange interaction and
filling of electrons. We have found that the ground state configurations
exhibit long range Ne\`el order, ferromagnetism or a mixture of both as is
varied. The magnetic moments of itinerant () and localized () electrons
are also studied. For the one-fourth filling case we found no magnetic moment
from - and -electrons for less than a critical value.Comment: 6 pages, 8 figure
All-optical logic circuits based on the polarization properties of non-degenerate four-wave mixing
This thesis investigates a new class of all-optical logic circuits that are based on the polarization properties of non-degenerate Four-Wave Mixing. Such circuits would be used in conjunction with a data modulation format where the information is coded on the states of polarization of the electric field. Schemes to perform multiple triple-product logic functions are discussed and it is shown that higher-level Boolean operations involving several bits can be implemented without resorting to the standard 2-input gates that are based on some form of switching. Instead, an entire hierarchy of more complex Boolean functions can be derived based on the selection rules of multi-photon scattering processes that can form a new class of primitive building blocks for digital circuits.
Possible applications of these circuits could involve some front-end signal processing to be performed all-optically in shared computer back-planes. As a simple illustration of this idea, a circuit performing error correction on a (3,1) Hamming Code is demonstrated. Error-free performance (Bit Error Rate of < 10^-9) at 2.5 Gbit/s is achieved after single-error correction on the Hamming word with 50 percent errors. The bit-rate is only limited by the bandwidth of available resources. Since Four-Wave Mixing is an ultrafast nonlinearity, these circuits offer the potential of computing at several terabits per second. Furthermore, it is shown that several Boolean functions can be performed in parallel in the same set of devices using different multi-photon scattering processes. The main objective of this thesis is to motivate a new paradigm of thought in digital circuit design. Challenges pertaining to the feasibility of these ideas are discusse
Autonomous Vehicles: Open-Source Technologies, Considerations, and Development
Autonomous vehicles are the culmination of advances in many areas such as
sensor technologies, artificial intelligence (AI), networking, and more. This
paper will introduce the reader to the technologies that build autonomous
vehicles. It will focus on open-source tools and libraries for autonomous
vehicle development, making it cheaper and easier for developers and
researchers to participate in the field. The topics covered are as follows.
First, we will discuss the sensors used in autonomous vehicles and summarize
their performance in different environments, costs, and unique features. Then
we will cover Simultaneous Localization and Mapping (SLAM) and algorithms for
each modality. Third, we will review popular open-source driving simulators, a
cost-effective way to train machine learning models and test vehicle software
performance. We will then highlight embedded operating systems and the security
and development considerations when choosing one. After that, we will discuss
Vehicle-to-Vehicle (V2V) and Internet-of-Vehicle (IoV) communication, which are
areas that fuse networking technologies with autonomous vehicles to extend
their functionality. We will then review the five levels of vehicle automation,
commercial and open-source Advanced Driving Assistance Systems, and their
features. Finally, we will touch on the major manufacturing and software
companies involved in the field, their investments, and their partnerships.
These topics will give the reader an understanding of the industry, its
technologies, active research, and the tools available for developers to build
autonomous vehicles.Comment: 13 pages, 7 figure
General discussion on self-assembly of biopolymers
General discussion on Biopolymer self assembl
Supporting Information: Fast, Copper-Free Click Chemistry, A Convenient Solid-Phase Approach to Oligonucleotide Conjugation
General experimental
Analytical TLC was performed on precoated (250 μm) silica gel 60 F-254 plates from Merck.
All plates were visualized by UV irradiation, and/or staining with 5% H2SO4 in ethanol
followed by heating. Flash chromatography grade silica gel 60 (230-400 mesh) was obtained
from Merck. Mass analysis was performed on an Ettan MALDI-TOF Pro from Amersham
Biosciences or LASER-TOF LT3 from Scientific Analytical Instruments with 3-
hydroxypicolinic acid or 2,’ 4’, 6’-trihydroxyacetophenone as matrix. The NMR spectra were
obtained at 1H (300 MHz), 13C (75 MHz) and 31P (121 MHz) on a Bruker instrument at 25 ºC.
Chemical shifts are reported in ppm downfield from TMS as standard. HPLC was carried out
using a Gilson instrument equipped with a UV detector and a Nucleosil C18 column (4.0 ×
250 mm) or Phenomenex Clarity. Fluorescence spectra were recorded on a Varian Cary
Eclipse instrument. All other chemical agents were purchased from Aldrich Chemical
Company unless otherwise noted
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