scholarly journals Chiral shape fluctuations and the origin of chirality in cholesteric phases of DNA origamis

2020 ◽  
Vol 6 (31) ◽  
pp. eaaw8331 ◽  
Author(s):  
Maxime M. C. Tortora ◽  
Garima Mishra ◽  
Domen Prešern ◽  
Jonathan P. K. Doye
Keyword(s):  
Broad Class ◽  
Cholesteric Liquid Crystal ◽  
Experimental Studies ◽  
Thermal Fluctuations ◽  
Dna Origami ◽  
Lyotropic Liquid Crystals ◽  
Colloidal Systems ◽  
Chiral Structure ◽  
Microscopic Features ◽  
Theoretical Evidence

Lyotropic cholesteric liquid crystal phases are ubiquitously observed in biological and synthetic polymer solutions, characterized by a complex interplay between thermal fluctuations and entropic and enthalpic forces. The elucidation of the link between microscopic features and macroscopic chiral structure, and of the relative roles of these competing contributions on phase organization, remains a topical issue. Here, we provide theoretical evidence of a previously unidentified mechanism of chirality amplification in lyotropic liquid crystals, whereby phase chirality is governed by fluctuation-stabilized helical deformations in the conformations of their constituent molecules. Our results compare favorably to recent experimental studies of DNA origami assemblies and demonstrate the influence of intramolecular mechanics on chiral supramolecular order, with potential implications for a broad class of experimentally relevant colloidal systems.

scholarly journals A theoretical verification of the integral fluctuation theorem for accelerated colloidal systems in the long-time limit

2021 ◽  
Author(s):  
Yash Lokare
Keyword(s):  
Steady State ◽  
Time Scales ◽  
Numerical Study ◽  
Quantitative Description ◽  
Experimental Studies ◽  
Fluctuation Theorem ◽  
Nonequilibrium Steady States ◽  
Small Scale ◽  
Colloidal Systems ◽  
Long Time

A quantitative description of the violation of the second law of thermodynamics in relatively small classical systems and over short time scales comes from the fluctuation-dissipation theorem. It has been well established both theoretically and experimentally, the validity of the fluctuation theorem to small scale systems that are disturbed from their initial equilibrium states. Some experimental studies in the past have also explored the validity of the fluctuation theorem to nonequilibrium steady states at long time scales in the asymptotic limit. To this end, a theoretical and/or purely numerical model of the integral fluctuation theorem has been presented. An approximate general expression for the dissipation function has been derived for accelerated colloidal systems trapped/confined in power-law traps. Thereafter, a colloidal particle trapped in a harmonic potential (generated by an accelerating one-dimensional optical trap) and undergoing Brownian motion has been considered for the numerical study. A toy model of a quartic potential trap in addition to the harmonic trap has also been considered for the numerical study. The results presented herein show that the integral fluctuation theorem applies not only to equilibrium steady state distributions but also to nonequilibrium steady state distributions of colloidal systems in accelerated frames of reference over long time scales.

On the analysis of the integral fluctuation theorem for accelerated colloidal systems in the long-time limit

2021 ◽  
Author(s):  
Yash Lokare
Keyword(s):  
Steady State ◽  
Time Scales ◽  
Numerical Study ◽  
Quantitative Description ◽  
Experimental Studies ◽  
Fluctuation Theorem ◽  
Nonequilibrium Steady States ◽  
Small Scale ◽  
Colloidal Systems ◽  
Long Time

Abstract A quantitative description of the violation of the second law of thermodynamics in relatively small classical systems and over short time scales comes from the fluctuation-dissipation theorem. It has been well established both theoretically and experimentally, the validity of the fluctuation theorem to small scale systems that are disturbed from their initial equilibrium states. Some experimental studies in the past have also explored the validity of the fluctuation theorem to nonequilibrium steady states at long time scales in the asymptotic limit. To this end, a theoretical and/or purely numerical model of the integral fluctuation theorem has been presented. An approximate general expression for the dissipation function has been derived for accelerated colloidal systems trapped/confined in power-law traps. Thereafter, a colloidal particle trapped in a harmonic potential (generated by an accelerating one-dimensional optical trap) and undergoing Brownian motion has been considered for the numerical study. A toy model of a quartic potential trap in addition to the harmonic trap has also been considered for the numerical study. The results presented herein show that the integral fluctuation theorem applies not only to equilibrium steady state distributions but also to nonequilibrium steady state distributions of colloidal systems in accelerated frames of reference over long time scales.

scholarly journals A Model of Brain Arteriolar Oxygen and Carbon Dioxide Transport during Anemia

1993 ◽  
Vol 13 (5) ◽  
pp. 872-880 ◽  
Author(s):  
Richard S. Schacterle ◽  
Robert J. Ribando ◽  
J. Milton Adams
Keyword(s):  
Carbon Dioxide ◽  
Mathematical Model ◽  
Blood Flow ◽  
Tissue Oxygenation ◽  
Normal Values ◽  
Experimental Studies ◽  
Limited Information ◽  
Carbon Dioxide Transport ◽  
Theoretical Evidence ◽  
Predicted Values

Existing experimental and theoretical evidence suggests that precapillary diffusion of O2 and CO2 occurs between arterioles and tissue under normal physiologic conditions. However, limited information is available on arteriolar gas transport during anemia. With use of a mathematical model of an arteriolar network in brain tissue, anemic hematocrits of 35, 25, and 15% were modeled to determine the effect of anemia on the exchange, the change in the equilibrium tissue O2 and CO2 tensions, and the increase in blood flow needed to restore tissue oxygenation. We found that the blood Po2 exiting the network fell from 66 mm Hg normally to 48 mm Hg during the severest anemia. Concurrently, the equilibrium tissue O2 tensions dropped from 44 to 23 mm Hg. For CO2 the exit blood Pco2 was 58 mm Hg for a 15% hematocrit, an increase of 4 mm Hg from the normal value, and equilibrium tissue Pco2 increased from 56 to 61 mm Hg. Blood flow increases from normal values necessary to offset the effects of the decreased O2 delivery to the tissue were 26, 86, and 222%, respectively, for hematocrits of 35, 25, and 15%. We compared our model results with recent experimental studies that have suggested that the amount of O2 diffusion is much higher than predicted values. We found that these experimental O2 gradients are three to four times larger than theoretical.

Fatigue Evaluation Incorporating Multiaxiality of Stress States

2005 ◽  
Author(s):  
Somnath Chattopadhyay
Keyword(s):  
Stress Distribution ◽  
Stress Concentrator ◽  
Experimental Studies ◽  
Peak Stress ◽  
Thermal Fluctuations ◽  
Feed Water ◽  
Critical Factors ◽  
Water Nozzle ◽  
Stress States ◽  
Fatigue Evaluation

In this work the effects of multiaxiality on the fatigue evaluation by the ASME Boiler and Pressure Vessel Code procedures have been assessed. The conservatism associated with the Ke factor has been critically appraised for fatigue evaluation using a design example of a feed water nozzle subjected to pressure and thermal fluctuations. A fictitious stress concentrator is applied to account for the ratio of the peak stress to the stress linearized through the thickness of the section under consideration. The effect of the traxiality of the stress distribution has also been assessed using the same design example for fatigue evaluations. Additional analytical and experimental studies have been recommended to study these important critical factors for fatigue assessment.

scholarly journals Development of Innovative Materials for Forensic Examination

2021 ◽  
pp. 22-26
Author(s):  
Tatyana Ermakova ◽  
◽  
Vasily Vasiliev ◽  
Vladimir Akatyev ◽  
◽  
...  
Keyword(s):  
Physical Modeling ◽  
Soft Tissues ◽  
Experimental Studies ◽  
Gunshot Wounds ◽  
Biological Tissues ◽  
Colloidal Systems ◽  
Synthetic Compound ◽  
Forensic Examination ◽  
Synthetic Materials ◽  
Innovative Materials

In the production of experimental studies related to the modeling of the behavior of human soft tissues in such widespread types of forensic examinations as forensic ballistic, tracological, forensic examination of cold and throwing weapons, forensic medical-use bioimitators. Human corpses, animal carcasses, and their living individuals are used as such objects, but in recent decades, with the development of chemistry and chemical technology, various artificial substitutes have become increasingly widespread – colloidal systems based on gelatin, soap, mixtures of petroleum petrolatum, as well as specialized compositions. Among the main advantages of using soft tissue substitutes are the following: visibility of the results obtained, availability of synthetic materials, uniformity of structure, reproducibility of experimental results with a statistically reliable amount, as well as, if necessary, the possibility of varying mechanical parameters for physical modeling of the characteristics of human biological tissues within the framework of an expert experiment. The paper proposes a technology for obtaining a reusable synthetic compound that allows modeling the properties of human soft tissues. The synthetic compound provides the transfer of general patterns of morphology of the formed gunshot injuries, similar to gunshot wounds on biological materials.

scholarly journals A Theoretical Analysis of the Integral Fluctuation Theorem for Accelerated Colloidal Systems in the Long-Time Limit

2021 ◽  
Author(s):  
Yash Lokare
Keyword(s):  
Steady State ◽  
Time Scales ◽  
Numerical Study ◽  
Quantitative Description ◽  
Experimental Studies ◽  
Fluctuation Theorem ◽  
Nonequilibrium Steady States ◽  
Small Scale ◽  
Colloidal Systems ◽  
Long Time

A quantitative description of the second law of thermodynamics in relatively small classical systems and over short time scales comes from the fluctuation-dissipation theorem. It has been well established both theoretically and experimentally, the validity of the fluctuation theorem to small scale systems that are disturbed from their initial equilibrium states. Some experimental studies in the past have also explored the validity of the fluctuation theorem to nonequilibrium steady states at long time scales in the asymptotic limit. To this end, a theoretical and/or purely numerical model of the integral fluctuation theorem has been presented. An approximate general expression for the dissipation function has been derived for accelerated colloidal systems trapped/confined in power-law traps. Thereafter, a colloidal particle trapped in a harmonic potential (generated by an accelerating one-dimensional optical trap) and undergoing Brownian motion has been considered for the numerical study. A toy model of a quartic potential trap in addition to the harmonic trap has also been considered for the numerical study. The results presented herein show that the integral fluctuation theorem applies not only to equilibrium steady state distributions but also to nonequilibrium steady state distributions of ideal colloidal systems in accelerated frames of reference over long time scales.

Pseudo-Rigid-Body Models of Compliant DNA Origami Mechanisms

2015 ◽  
Author(s):  
Lifeng Zhou ◽  
Alexander E. Marras ◽  
Carlos E. Castro ◽  
Hai-jun Su
Keyword(s):  
Rigid Body ◽  
Strain Energy ◽  
Compliant Mechanisms ◽  
Compliant Mechanism ◽  
Mechanical Energy ◽  
Energy Landscape ◽  
Thermal Fluctuations ◽  
Dna Origami ◽  
Double Stranded Dna ◽  
Flexible Parts

In this paper, we introduce the strategy of designing and analyzing compliant nanomechanisms fabricated with DNA origami which we call compliant DNA origami mechanism (CDOM). The rigid, compliant and flexible parts are constructed by a bunch of double-stranded DNA (dsDNA) helices, fewer dsDNA helices and single-stranded DNA (ssDNA) strands respectively. Just like in macroscopic compliant mechanisms, a CDOM generates its motion via deformation of at least one structural member. During the motion, strain energy is stored and released in the mechanism. These CDOM can suppress thermal fluctuations due to the internal mechanical energy barrier for motion. An example of compliant hinge joint and a bistable four-bar CDOM fabricated with DNA origami are discussed at the end of this paper. The classic pseudo-rigid-body (PRB) model for compliant mechanism is successfully employed to the analysis of these DNA origami nanomechanisms. This PRB model has been used to guide the design of a bistable CDOM for a desired energy landscape.

scholarly journals Artificial colloidal liquid metacrystals by shearing microlithography

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Yanqiu Jiang ◽  
Fan Guo ◽  
Zhen Xu ◽  
Weiwei Gao ◽  
Chao Gao
Keyword(s):  
Liquid Crystals ◽  
Liquid Crystalline ◽  
Molecular Size ◽  
Digital Design ◽  
Lyotropic Liquid Crystals ◽  
Colloidal Systems ◽  
Extended Form ◽  
Crystalline Materials ◽  
Liquid Crystalline Materials ◽  
External Stimuli

Abstract Meta-periodicity beyond intrinsic atomic and molecular order, such as metacrystalline and quasicrystalline lattices, exists in solids, but is usually elusive in lyotropic liquid crystals for its energetic instability. The stable meta-periodicity in lyotropic liquid crystals in the absence of external stimuli remains unexplored, and how to achieve it keeps a great challenge. Here we create lyotropic liquid crystals with stable meta-periodicity in a free state, coined as liquid metacrystals, in colloidal systems by an invented shearing microlithography. The meta-periodicity is dynamically stabilized by the giant molecular size and strong excluded volume repulsion. Liquid metacrystals are designed to completely cover a library of symmetries, including five Bravais and six quasicrystalline lattices. Liquid metacrystal promises an extended form of liquid crystals with rich meta-periodicity and the shearing microlithography emerges as a facile technology to fabricate liquid meta-structures and metamaterials, enabling the digital design of structures and functionalities of liquid crystalline materials.

scholarly journals FPGA-Oriented LDPC Decoder for Cyber-Physical Systems

Mathematics ◽  
2020 ◽  
Vol 8 (5) ◽  
pp. 723 ◽  
Author(s):  
Mateusz Kuc ◽  
Wojciech Sułek ◽  
Dariusz Kania
Keyword(s):  
Forward Error Correction ◽  
Broad Class ◽  
Experimental Studies ◽  
Cyber Physical Systems ◽  
Coding System ◽  
Physical Systems ◽  
Testing Environment ◽  
Ldpc Decoder ◽  
Coding Systems ◽  
Forward Error

A potentially useful Cyber-Physical Systems element is a modern forward error correction (FEC) coding system, utilizing a code selected from the broad class of Low-Density Parity-Check (LDPC) codes. In this paper, development of a hardware implementation in an FPGAs of the decoder for Quasi-Cyclic (QC-LDPC) subclass of codes is presented. The decoder can be configured to support the typical decoding algorithms: Min-Sum or Normalized Min-Sum (NMS). A novel method of normalization in the NMS algorithm is proposed, one that utilizes combinational logic instead of arithmetic units. A comparison of decoders with different bit-lengths of data (beliefs that are messages propagated between computing units) is also provided. The presented decoder has been implemented with a distributed control system. Experimental studies were conducted using the Intel Cyclone V FPGA module, which is a part of the developed testing environment for LDPC coding systems.

Sign in / Sign up

Export Citation Format

Share Document