414 research outputs found
Dynamics of equilibrium linked colloidal gels
Colloids that attractively bond to only a few neighbors (e.g., patchy
particles) can form equilibrium gels with distinctive dynamic properties that
are stable in time. Here, we use a coarse-grained model to explore the dynamics
of linked networks of patchy colloids whose average valence is macroscopically,
rather than microscopically, constrained. Simulation results for the model show
dynamic hallmarks of equilibrium gel formation and establish that the
colloid-colloid bond persistence time controls the characteristic slow
relaxation of the self-intermediate scattering function. The model features
re-entrant network formation without phase separation as a function of linker
concentration, centered at the stoichiometric ratio of linker ends to
nanoparticle surface bonding sites. Departures from stoichiometry result in
linker-starved or site-starved networks with reduced connectivity and shorter
characteristic relaxation times with lower activation energies. Underlying the
re-entrant trends, dynamic properties vary monotonically with the number of
effective network bonds per colloid, a quantity that can be predicted using
Wertheim's thermodynamic perturbation theory. These behaviors suggest
macroscopic in situ strategies for tuning the dynamical response of colloidal
networks.Comment: 25 pages, 9 figure
Field-control, phase-transitions, and life's emergence
Instances of critical-like characteristics in living systems at each
organizational level as well as the spontaneous emergence of computation
(Langton), indicate the relevance of self-organized criticality (SOC). But
extrapolating complex bio-systems to life's origins, brings up a paradox: how
could simple organics--lacking the 'soft matter' response properties of today's
bio-molecules--have dissipated energy from primordial reactions in a controlled
manner for their 'ordering'? Nevertheless, a causal link of life's macroscopic
irreversible dynamics to the microscopic reversible laws of statistical
mechanics is indicated via the 'functional-takeover' of a soft magnetic
scaffold by organics (c.f. Cairns-Smith's 'crystal-scaffold'). A
field-controlled structure offers a mechanism for bootstrapping--bottom-up
assembly with top-down control: its super-paramagnetic components obey
reversible dynamics, but its dissipation of H-field energy for aggregation
breaks time-reversal symmetry. The responsive adjustments of the controlled
(host) mineral system to environmental changes would bring about mutual
coupling between random organic sets supported by it; here the generation of
long-range correlations within organic (guest) networks could include SOC-like
mechanisms. And, such cooperative adjustments enable the selection of the
functional configuration by altering the inorganic network's capacity to assist
a spontaneous process. A non-equilibrium dynamics could now drive the
kinetically-oriented system towards a series of phase-transitions with
appropriate organic replacements 'taking-over' its functions.Comment: 54 pages, pdf fil
Magnetism, FeS colloids, and Origins of Life
A number of features of living systems: reversible interactions and weak
bonds underlying motor-dynamics; gel-sol transitions; cellular connected
fractal organization; asymmetry in interactions and organization; quantum
coherent phenomena; to name some, can have a natural accounting via
interactions, which we therefore seek to incorporate by expanding the horizons
of `chemistry-only' approaches to the origins of life. It is suggested that the
magnetic 'face' of the minerals from the inorganic world, recognized to have
played a pivotal role in initiating Life, may throw light on some of these
issues. A magnetic environment in the form of rocks in the Hadean Ocean could
have enabled the accretion and therefore an ordered confinement of
super-paramagnetic colloids within a structured phase. A moderate H-field can
help magnetic nano-particles to not only overcome thermal fluctuations but also
harness them. Such controlled dynamics brings in the possibility of accessing
quantum effects, which together with frustrations in magnetic ordering and
hysteresis (a natural mechanism for a primitive memory) could throw light on
the birth of biological information which, as Abel argues, requires a
combination of order and complexity. This scenario gains strength from
observations of scale-free framboidal forms of the greigite mineral, with a
magnetic basis of assembly. And greigite's metabolic potential plays a key role
in the mound scenario of Russell and coworkers-an expansion of which is
suggested for including magnetism.Comment: 42 pages, 5 figures, to be published in A.R. Memorial volume, Ed
Krishnaswami Alladi, Springer 201
์ง์ง ์ด์ค์ธต ์ ํ๋ผ์ฆ๋ชจ๋ ๋๋ ธ์ ์ ๊ธฐ๋ฐ ๋๋ ธ๋ฐ์ด์ค ๊ฒ์ง ๋ฐ ์ปดํจํ
ํ์๋
ผ๋ฌธ (๋ฐ์ฌ)-- ์์ธ๋ํ๊ต ๋ํ์ : ์์ฐ๊ณผํ๋ํ ํํ๋ถ, 2019. 2. ๋จ์ข๋ฏผ.Supported lipid bilayer is a two-dimensional lipid bilayer self-assembled on a hydrophilic substrate with two-dimensional fluidity. By introducing plasmonic nanoparticles with strong scattering signals into the supported lipid bilayer, it is possible to observe and track thousands of nanoparticles and their interactions at a single-nanoparticle level in real time. In this thesis, I expand the nanoparticle-lipid bilayer platform by engineering plasmonic nanoparticles to construct a complex nanoparticle network system and develop multiplexed bio-detection and bio-computing strategies.
Chapter 1 describes a supported lipid bilayer platform incorporating plasmonic nanoparticles. Section 1 introduces the optical properties and biosensing application of plasmonic nanoparticles, and Section 2 introduces tethering technique, characteristics, and advantages for introducing nanoparticles into supported lipid bilayer platforms. In Chapter 2, I introduce a system that can distinguish nine types of nanoparticle assembly reactions occurring simultaneously by introducing optically encoded plasmonic nanoparticles that scatter red, blue, and green light into supported lipid bilayers. I performed multiplexed detection of nine types of microRNAs, which are important gene regulators and cancer cell biomarker. In Chapter 3, I develop a bio-computing platform that recognizes molecular inputs, performs logic circuits, and generates nanoparticle assembly/disassembly output signals. Complex logic circuits are designed and implemented by combining two strategies: (i) interfacial design that constructs a logic circuit through DNA functionalization of the interface of nanoparticles, and (ii) a network design that connects assembly/disassembly reactions. In Chapter 4, I develop a bio-computing calculator capable of performing arithmetic logic operations. I use the nanoparticle-lipid bilayer platform as the hardware that stores, processes, and outputs information, and constructs software that contains logic circuit functions through DNA solution. An information storage nanoparticle stores solution-phase molecular input signals on the surface of nanoparticles. The bio-computing lipid nanotablet recognizes an arithmetic logic circuit programmed with DNA information and generates outputs a result of a kinetic difference between nanoparticle assembly reaction according to the storage state of the input signal.์ง์งํ ์ง์ง ์ด์ค์ธต์ ์น์์ฑ ๊ธฐํ ์์ ์กฐ๋ฆฝ๋ 2์ฐจ์์ ์ง์ง ์ด์ค์ธต์ผ๋ก 2์ฐจ์ ์์ ์ ๋์ฑ์ ๊ฐ์ง๋ค. ์ง์งํ ์ง์ง ์ด์ค์ธต์ ๊ฐํ ์ฐ๋ ์ ํธ๋ฅผ ์ง๋๋ ํ๋ผ์ฆ๋ชจ๋ ๋๋
ธ์
์๋ฅผ ๋์
ํ๋ฉด ์์ฒ ๊ฐ์ ๋๋
ธ์
์์ ๊ทธ ์ํธ์์ฉ์ ๋จ์ผ ๋๋
ธ์
์ ์์ค์ผ๋ก ์ค์๊ฐ ๊ด์ฐฐ์ด ๊ฐ๋ฅํ๋ค. ๋ณธ ํ์๋
ผ๋ฌธ์์๋ ๋๋
ธ์
์-์ง์ง ์ด์ค์ธต ํ๋ซํผ์์์ ๋๋
ธ์
์ ์ข
๋ฅ ๋ฐ ๊ฐ์ง ๋ฐฉ๋ฒ์ ํ์ฅํ์ฌ ๋ณต์กํ ๋๋
ธ์
์ ๋คํธ์ํฌ ์์คํ
์ ๊ตฌ์ฑํ๊ณ , ๋ฐ์ด์ค ๊ฒ์ง, ๋ฐ์ด์ค ์ปดํจํ
์์ฉ์ ๊ฐ๋ฐํ๋ค.
1์ฅ์์๋ ํ๋ผ์ฆ๋ชจ๋ ๋๋
ธ์
์๊ฐ ๋์
๋ ์ง์งํ ์ง์ง ์ด์ค์ธต ํ๋ซํผ์ ์ค๋ช
ํ๋ค. 1์ ์์ ํ๋ผ์ฆ๋ชจ๋ ๋๋
ธ์
์์ ๊ดํ์ ํน์ฑ๊ณผ ์ฐ๋์ ํธ๋ฅผ ์ด์ฉํ ๋ฐ์ด์ค์ผ์ฑ ์์ฉ ์ฐ๊ตฌ๋ฅผ ์๊ฐํ๊ณ 2์ ์์๋ ์ง์งํ ์ง์ง ์ด์ค์ธต ํ๋ซํผ์ ๋๋
ธ์
์์ ๋์
๋ฐฉ๋ฒ, ํน์ง, ์ฅ์ , ๋ถ์๋ฐฉ๋ฒ ๋ฑ์ ์๊ฐํ๋ค. 2์ฅ์์๋ ๋นจ๊ฐ, ์ด๋ก, ํ๋ ๋น์ ์ฐ๋ํ๋ ํ๋ผ์ฆ๋ชจ๋ ๋๋
ธ์
์๋ฅผ ํฉ์ฑํ๊ณ , ์ง์งํ ์ง์ง ์ด์ค์ธต์ ๋์
ํ์ฌ ๋์์ ์ผ์ด๋๋ 9์ข
๋ฅ์ ๋๋
ธ์
์ ๊ฒฐํฉ ๋ฐ์์ ๊ฐ๊ฐ ๊ตฌ๋ถํ ์ ์๋ ํ๋ซํผ์ ๊ฐ๋ฐํ๋ค. ์ด๋ฅผ ์ด์ฉํ์ฌ ์ธํฌ ๋ด ์ค์ํ ๋จ๋ฐฑ์ง ๋ฒ์ญ ์กฐ์ ๋ฌผ์ง์ด์ ์ ๋ฐ์ด์ค๋ง์ปค์ธ ๋ง์ดํฌ๋กRNA๋ฅผ ๋์ ๋ค์ค ๊ฒ์งํ๋ค. 3์ฅ์์๋ ์ง์งํ ์ง์ง ์ด์ค์ธต ์์ ๋์
๋ ๋๋
ธ์
์๋ฅผ ๋ค์ข
์ DNA๋ก ๊ธฐ๋ฅํํ์ฌ ํน์ DNA ๋ถ์ ์
๋ ฅ ์ ํธ ์ธ์, ๋
ผ๋ฆฌํ๋ก ์ํ, ๋๋
ธ์
์ ๊ฒฐํฉ/๋ถ๋ฆฌ ์ถ๋ ฅ ์ ํธ ์์ฑํ๋ ๋ฐ์ด์ค ์ปดํจํ
ํ๋ซํผ์ ๊ฐ๋ฐํ๋ค. ๋๋
ธ์
์์ ๊ณ๋ฉด์ DNA๋ก ๋์์ธํ์ฌ ๋
ผ๋ฆฌ ํ๋ก๋ฅผ ๊ตฌ์ฑํ๋ ์ธํฐํ์ด์ค ํ๋ก๊ทธ๋๋ฐ๊ณผ ๋๋
ธ์
์์ ๊ฒฐํฉ/๋ถ๋ฆฌ ๋ฐ์์ ์ฐ๊ฒฐํ์ฌ ๋คํธ์ํฌ๋ฅผ ๋์์ธํ์ฌ ๋
ผ๋ฆฌ ํ๋ก๋ฅผ ์ง์ ํ๋ ๋คํธ์ํฌ ํ๋ก๊ทธ๋๋ฐ์ ์กฐํฉํ์ฌ ๋ณต์กํ ๋
ผ๋ฆฌ ํ๋ก๋ฅผ ์ค๊ณํ๊ณ ์ํํ๋ค. 4์ฅ์์๋ ์ง์งํ ์ง์ง ์ด์ค์ธต์ ๋์
๋ ๋๋
ธ์
์ ํ๋ฉด์ ์ฉ์ก ์ ๋ถ์ ์
๋ ฅ์ ํธ๋ฅผ ์ ์ฅํ๋ ์ ๋ณด ์ ์ฅ ์ฅ์น๋ฅผ ๊ฐ๋ฐํ๊ณ ๋ชจ๋ ์ข
๋ฅ์ ์ฐ์ ๋
ผ๋ฆฌ์ฐ์ฐ์ ์ํํ ์ ์๋ ์๋ถ์ ๊ณ์ฐ๊ธฐ์ ๊ฐ๋ฐํ๋ค. ๋๋
ธ์
์-์ง์ง ์ด์ค์ธต ํ๋ซํผ์ ์ ๋ณด์ ์ฅ, ์ํ, ์ถ๋ ฅํ๋ ๋งค์ฒด์ธ ํ๋์จ์ด๋ก ์ด์ฉํ๊ณ , DNA ๋ถ์ ์กฐํฉ ์ฉ์ก์ ์ฐ์ ๋
ผ๋ฆฌํ๋ก ๊ธฐ๋ฅ์ ๋ด๊ณ ์๋ ์ํํธ์จ์ด๋ก ๊ตฌ์ฑํ๋ค. ๋ฐ์ด์ค ์ปดํจํ
์นฉ์ DNA ์ ๋ณด๋ก ํ๋ก๊ทธ๋๋ฐ๋ ์ฐ์ ๋
ผ๋ฆฌํ๋ก๋ฅผ ์ธ์ํ์ฌ ์
๋ ฅ์ ํธ์ ์ ์ฅ ์ํ์ ๋ฐ๋ผ ๋๋
ธ์
์ ๊ฒฐํฉ ๋ฐ์์ ๋ฐ์์๋์ ์ฐจ์ด๋ฅผ ์ผ์ผํค๊ณ ๊ฒฐ๊ณผ๋ฅผ ์ถ๋ ฅํ๋ค.Chapter 1. Introduction: Plasmonic Nanoparticle-Tethered Supported Lipid Bilayer Platform 1
1.1. Plasmonic Nanoparticles and Their Bio-Applications 2
1.1.1. Introduction 4
1.1.2. Fundamentals of Plasmonic Nanoparticles 8
1.1.3. Plasmonic Nanoparticle Engineering for Biological Application 11
1.1.4. Plasmonic Nanoparticles for Rayleigh Scattering-Based Biosensing 16
1.1.5. References 21
1. 2. Supported Lipid Bilayer as a Dynamic Platform 24
1.2.1. Introduction 26
1.2.2. Basic Setups and Strategies 29
1.2.3. Nanoparticle-Tethering Techniques 33
1.2.4. Real-Time Imaging and Tracking of Single Nanoparticles on SLB 39
1.2.5. Observation of Interactions between Single Nanoparticles 44
1.2.6. References 50
Chapter 2. Multiplexed Biomolecular Detection Strategy 53
2.1. Introduction 55
2.2. Experimental Section 60
2.3. Results and Discussion 66
2.4. Conclusion 77
2.5. Supporting Information 79
2.6. References 83
Chapter 3. Nano-Bio Computing on Lipid Bilayer 84
3.1. Introduction 85
3.2. Experimental Section 88
3.3. Results and Discussion 98
3.4. Conclusion 120
3.5. Supporting Information 124
3.6. References 161
Chapter 4. Development of Nanoparticle Architecture for Biomolecular Arithmetic Logic Operation 163
4.1. Introduction 165
4.2. Experimental Section 167
4.3. Results and Discussion 171
4.4. Conclusion 177
4.5. References 179
Abstract in Korean 180Docto
Electromagnetic Energy Coupled to Nanomaterial Composites for Polymer Manufacturing
Polymer nano-composites may be engineered with specific electrical properties to achieve good coupling with electromagnetic energy sources. This enables a wide range of novel processing techniques where controlling the precise thermal profile is critical. Composite materials were characterized with a variety of electrical and thermographic analysis methods to capture their response to electromagnetic energy. COMSOL finite element analysis software was used to model the electric fields and resultant thermal profiles in selected samples. Applications of this technology are demonstrated, including the use of microwave and radio frequency energy to thermally weld the interfaces of 3D printed parts together for increased interlayer (Z) strength. We also demonstrate the ability to bond various substrates with carbon nanotube/epoxy composite adhesives using radio frequency electromagnetic heating to rapidly cure the adhesive interface. The results of this work include 3D printed parts with mechanical properties equal to injection molded samples, and RF bonded joints cured 40% faster than traditional oven curing
Algebarska topologija kompleksnih mreลพa i topoloลกki aspekti nelinearnih dinamiฤkih sistema
Da bi razumeli i eventualno predvideli ponaลกanje kompleksnih sistema koji se javljaju
u raznim oblastima nauke, od socio-ekonomskih do sistema iz, na primer, fizike
ili biologije, i koji imaju vaลพan uticaj na razne aspekte naลกih ลพivota, nauฤnici su
razvili veliki broj metoda i modela.To understand and eventually predict the behavior of complex systems arising
from diverse areas of science such as physics, economics or biology, which have
a widespread impact on our lives, many powerful methods and models have been
developed in the recent years
Present and future of surface-enhanced Raman scattering
The discovery of the enhancement of Raman scattering by molecules adsorbed on nanostructured metal surfaces is a landmark in the history of spectroscopic and analytical techniques. Significant experimental and theoretical effort has been directed toward understanding the surface-enhanced Raman scattering (SERS) effect and demonstrating its potential in various types of ultrasensitive sensing applications in a wide variety of fields. In the 45 years since its discovery, SERS has blossomed into a rich area of research and technology, but additional efforts are still needed before it can be routinely used analytically and in commercial products. In this Review, prominent authors from around the world joined together to summarize the state of the art in understanding and using SERS and to predict what can be expected in the near future in terms of research, applications, and technological development. This Review is dedicated to SERS pioneer and our coauthor, the late Prof. Richard Van Duyne, whom we lost during the preparation of this article
Recommended from our members
Resilient Pathways to Atomic Attachment of Quantum Dot Dimers and Artificial Solids from Faceted CdSe Quantum Dot Building Blocks.
The goal of this work is to identify favored pathways for preparation of defect-resilient attached wurtzite CdX (X = S, Se, Te) nanocrystals. We seek guidelines for oriented attachment of faceted nanocrystals that are most likely to yield pairs of nanocrystals with either few or no electronic defects or electronic defects that are in and of themselves desirable and stable. Using a combination of in situ high-resolution transmission electron microscopy (HRTEM) and electronic structure calculations, we evaluate the relative merits of atomic attachment of wurtzite CdSe nanocrystals on the {11ฬ
00} or {112ฬ
0} family of facets. Pairwise attachment on either facet can lead to perfect interfaces, provided the nanocrystal facets are perfectly flat and the angles between the nanocrystals can adjust during the assembly. Considering defective attachment, we observe for {11ฬ
00} facet attachment that only one type of edge dislocation forms, creating deep hole traps. For {112ฬ
0} facet attachment, we observe that four distinct types of extended defects form, some of which lead to deep hole traps whereas others only to shallow hole traps. HRTEM movies of the dislocation dynamics show that dislocations at {11ฬ
00} interfaces can be removed, albeit slowly. Whereas only some extended defects at {112ฬ
0} interfaces could be removed, others were trapped at the interface. Based on these insights, we identify the most resilient pathways to atomic attachment of pairs of wurtzite CdX nanocrystals and consider how these insights can translate to the creation of electronically useful materials from quantum dots with other crystal structures
- โฆ