scholarly journals Chemical unfolding of protein domains induces shape change in programmed protein hydrogels

2019 ◽  
Author(s):  
Luai R. Khoury ◽  
Ionel Popa
Keyword(s):  
Protein Unfolding ◽  
Shape Change ◽  
Protein Domains ◽  
Fold Increase ◽  
Protein Mechanics ◽  
Protein Polymer ◽  
Novel Approach ◽  
Wide Range ◽  
Biomechanical Response ◽  
Protein Hydrogels

Abstract Programmable behavior combined with tailored stiffness and tunable biomechanical response are key requirements for developing successful materials. However, these properties are still an elusive goal for protein-based biomaterials. Here, we present a new method based on protein-polymer interactions, to manipulate the stiffness of protein-based hydrogels made from bovine serum albumin (BSA) by using polyelectrolytes such as poly(Ethelene)imine (PEI) and poly-L-lysine (PLL) at various concentrations. This approach confers protein-hydrogels tunable wide-range stiffness, from ~ 10 - 60 kPa when treated with PEI, without affecting the protein mechanics and nanostructure. We ascribe the increase in stiffness to the synergistic effect of the non-covalent electrostatic polymer-protein interaction, as well as the polymer-shell that stabilizes the protein domains nanomechanics. We use the 6-fold increase in stiffness induced by PEI to program BSA-hydrogels in various shapes. By utilizing the characteristic protein unfolding we can induce reversible shape-memory behavior of these composite materials using chemical denaturing solutions. We anticipate this novel approach based on protein engineering and polymer reinforcing will enable the development and investigation of new smart biomaterials and extend protein hydrogel capabilities beyond their conventional applications.

scholarly journals Chemical unfolding of protein domains induces shape change in programmed protein hydrogels

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Luai R. Khoury ◽  
Ionel Popa
Keyword(s):  
Protein Unfolding ◽  
Shape Change ◽  
Fold Increase ◽  
Protein Mechanics ◽  
Protein Polymer ◽  
Wide Range ◽  
Biomechanical Response ◽  
Polymer Interactions ◽  
Smart Biomaterials ◽  
Protein Hydrogels

AbstractProgrammable behavior combined with tailored stiffness and tunable biomechanical response are key requirements for developing successful materials. However, these properties are still an elusive goal for protein-based biomaterials. Here, we use protein-polymer interactions to manipulate the stiffness of protein-based hydrogels made from bovine serum albumin (BSA) by using polyelectrolytes such as polyethyleneimine (PEI) and poly-L-lysine (PLL) at various concentrations. This approach confers protein-hydrogels with tunable wide-range stiffness, from ~10–64 kPa, without affecting the protein mechanics and nanostructure. We use the 6-fold increase in stiffness induced by PEI to program BSA hydrogels in various shapes. By utilizing the characteristic protein unfolding we can induce reversible shape-memory behavior of these composite materials using chemical denaturing solutions. The approach demonstrated here, based on protein engineering and polymer reinforcing, may enable the development and investigation of smart biomaterials and extend protein hydrogel capabilities beyond their conventional applications.

scholarly journals Modeling Protein-based Hydrogels under Force

2018 ◽  
Author(s):  
Kirill Shmilovich ◽  
Ionel Popa
Keyword(s):  
Phase Transition ◽  
Mechanical Response ◽  
Network Dynamics ◽  
Protein Domains ◽  
Cross Linking ◽  
Ensemble Approach ◽  
Biomechanical Response ◽  
Protein Molecules ◽  
Scale Down ◽  
Protein Hydrogels

Hydrogels made from structured polyprotein domains combine the properties of cross-linked polymers with the unfolding phase transition. The use of protein hydrogels as an ensemble approach to study the physics of domain unfolding is limited by the lack of scaling tools and by the complexity of the system. Here we propose a model to describe the biomechanical response of protein hydrogels based on the unfolding and extension of protein domains under force. Our model takes into account the contributions on the network dynamics of the molecules inside the gels, which have random cross-linking points and random topology. This model reproduces reported macroscopic visco-elastic effects and constitutes an important step toward using rheometry on protein hydrogels to scale down to the average mechanical response of protein molecules.

Microstructural characterization of laser-melted/roller-quenched dicalcium silicate

1988 ◽  
Vol 46 ◽  
pp. 582-583
Author(s):  
C. J. Chan ◽  
K. R. Venkatachari ◽  
W. M. Kriven ◽  
J. F. Young
Keyword(s):  
Particle Size ◽  
Raw Materials ◽  
Shape Change ◽  
Microstructural Characterization ◽  
Particle Size Effect ◽  
Dicalcium Silicate ◽  
Laser Melting ◽  
Uniform Size ◽  
Cell Shape Change ◽  
Wide Range

Dicalcium silicate (Ca2SiO4) is a major component of Portland cement. It has also been investigated as a potential transformation toughener alternative to zirconia. It has five polymorphs: α, α'H, α'L, β and γ. Of interest is the β-to-γ transformation on cooling at about 490°C. This transformation, accompanied by a 12% volume increase and a 4.6° unit cell shape change, is analogous to the tetragonal-to-monoclinic transformation in zirconia. Due to the processing methods used, previous studies into the particle size effect were limited by a wide range of particle size distribution. In an attempt to obtain a more uniform size, a fast quench rate involving a laser-melting/roller-quenching technique was investigated.The laser-melting/roller-quenching experiment used precompacted bars of stoichiometric γ-Ca2SiO4 powder, which were synthesized from AR grade CaCO3 and SiO2xH2O. The raw materials were mixed by conventional ceramic processing techniques, and sintered at 1450°C. The dusted γ-Ca2SiO4 powder was uniaxially pressed into 0.4 cm x 0.4 cm x 4 cm bars under 34 MPa and cold isostatically pressed under 172 MPa. The γ-Ca2SiO4 bars were melted by a 10 KW-CO2 laser.

scholarly journals Responsive and Personalized Web Layouts with Integer Programming

2021 ◽  
Vol 5 (EICS) ◽  
pp. 1-23
Author(s):  
Markku Laine ◽  
Yu Zhang ◽  
Simo Santala ◽  
Jussi P. P. Jokinen ◽  
Antti Oulasvirta
Keyword(s):  
Integer Programming ◽  
Web Design ◽  
Web Pages ◽  
Web Page Design ◽  
Automated Generation ◽  
Novel Approach ◽  
Wide Range ◽  
Responsive Design ◽  
Responsive Web Design ◽  
Page Design

Over the past decade, responsive web design (RWD) has become the de facto standard for adapting web pages to a wide range of devices used for browsing. While RWD has improved the usability of web pages, it is not without drawbacks and limitations: designers and developers must manually design the web layouts for multiple screen sizes and implement associated adaptation rules, and its "one responsive design fits all" approach lacks support for personalization. This paper presents a novel approach for automated generation of responsive and personalized web layouts. Given an existing web page design and preferences related to design objectives, our integer programming -based optimizer generates a consistent set of web designs. Where relevant data is available, these can be further automatically personalized for the user and browsing device. The paper includes presentation of techniques for runtime adaptation of the designs generated into a fully responsive grid layout for web browsing. Results from our ratings-based online studies with end users (N = 86) and designers (N = 64) show that the proposed approach can automatically create high-quality responsive web layouts for a variety of real-world websites.

scholarly journals Density Guarantee on Finding Multiple Subgraphs and Subtensors

2021 ◽  
Vol 15 (5) ◽  
pp. 1-32
Author(s):  
Quang-huy Duong ◽  
Heri Ramampiaro ◽  
Kjetil Nørvåg ◽  
Thu-lan Dam
Keyword(s):  
Lower Bound ◽  
State Of The Art ◽  
The State ◽  
The Other ◽  
Exact Methods ◽  
Practical Solution ◽  
Novel Approach ◽  
Wide Range ◽  
Real World Datasets ◽  
Tensor Data

Dense subregion (subgraph & subtensor) detection is a well-studied area, with a wide range of applications, and numerous efficient approaches and algorithms have been proposed. Approximation approaches are commonly used for detecting dense subregions due to the complexity of the exact methods. Existing algorithms are generally efficient for dense subtensor and subgraph detection, and can perform well in many applications. However, most of the existing works utilize the state-or-the-art greedy 2-approximation algorithm to capably provide solutions with a loose theoretical density guarantee. The main drawback of most of these algorithms is that they can estimate only one subtensor, or subgraph, at a time, with a low guarantee on its density. While some methods can, on the other hand, estimate multiple subtensors, they can give a guarantee on the density with respect to the input tensor for the first estimated subsensor only. We address these drawbacks by providing both theoretical and practical solution for estimating multiple dense subtensors in tensor data and giving a higher lower bound of the density. In particular, we guarantee and prove a higher bound of the lower-bound density of the estimated subgraph and subtensors. We also propose a novel approach to show that there are multiple dense subtensors with a guarantee on its density that is greater than the lower bound used in the state-of-the-art algorithms. We evaluate our approach with extensive experiments on several real-world datasets, which demonstrates its efficiency and feasibility.

scholarly journals An Advanced Educational Tool for Digital Forensic Engineering

2016 ◽  
Vol 11 (03) ◽  
pp. 15 ◽  
Author(s):  
Primož Cigoj ◽  
Borka Jerman Blažič
Keyword(s):  
Digital Forensics ◽  
Real Life ◽  
University Education ◽  
Educational Tool ◽  
Digital Tool ◽  
College And University ◽  
Novel Approach ◽  
Wide Range ◽  
E Learning ◽  
Forensic Engineering

This paper presents a novel approach to education in the area of digital forensics based on a multi-platform cloud-computer infrastructure and an innovative computer based tool. The tool is installed and available through the cloud-based infrastructure of the Dynamic Forensic Education Alliance. Cloud computing provides an efficient mechanism for a wide range of services that offer real-life environments for teaching and training cybersecurity and digital forensics. The cloud-based infrastructure, the virtualized environment and the developed educational tool enable the construction of a dynamic e-learning environment making the training very close to reality and to real-life situations. The paper presents the Dynamic Forensic Digital tool named EduFors and describes the different levels of college and university education where the tool is introduced and used in the training of future investigators of cybercrime events.

Multiphysics Modeling and Experimental Validation of Reconfigurable, E-Textile Origami Antennas

2018 ◽  
Author(s):  
Hamil Shah ◽  
Abdullahi Inshaar ◽  
Chengzhe Zou ◽  
Shreyas Chaudhari ◽  
Saad Alharbi ◽  
...  
Keyword(s):  
Antenna Arrays ◽  
Shape Change ◽  
Wave Radiation ◽  
Patch Antennas ◽  
Multiphysics Modeling ◽  
Textile Materials ◽  
New Class ◽  
Non Invasive ◽  
Radiation Properties ◽  
Wide Range

Physical deformation mechanisms are emerging as compelling and simple ways to adapt radio frequency (RF) characteristics of antennas in contrast to digital steering approaches acting on topologically fixed antennas. Concepts of physical reconfigurability also enable exceptional capabilities such as deployable and morphing antenna arrays that serve multiple functions and permit compact transport with ease. Yet, the emergent concepts lack broad understanding of effective approaches to integrate conformal, electrically conductive architectures with high-compliance foldable frameworks. To explore this essential interface where electrical demands and mechanical requirements may conflict, this research introduces a new class of origami-based tessellated antennas whose RF characteristics are self-tuned by physical reconfiguration of the antenna shape. E-textile materials are used to permit large antenna shape change while maintaining electrical conductivity. Dipole and patch antennas are considered as conventional antenna platforms upon which to innovate with the e-textile origami concept. Multiphysics modeling efforts establish the efficacy of foldable antenna geometries for broad tailoring of the RF characteristics. Experiments with proof-of-concept antennas confirm the large adaptability of wave radiation properties enabled by the reconfiguration of the e-textile origami surfaces. The results suggest that e-textile antennas can be integrated into clothing and mechanical structures, providing a non-invasive way of quantifying deformation for a wide range of applications.

scholarly journals SWOT analysis of plant health clinics as perceived by plant doctors in Nepal

2018 ◽  
pp. 137-146
Author(s):  
R. K. Adhikari ◽  
P. P. Regmi ◽  
R. B Thapa ◽  
Y. D. G.C. ◽  
E. Boa
Keyword(s):  
Online Survey ◽  
Swot Analysis ◽  
Plant Health ◽  
Survey Tool ◽  
Extension System ◽  
Health Clinics ◽  
Novel Approach ◽  
Wide Range ◽  
Plant Clinics ◽  
External Forces

 This paper identified and examined the internal and external forces that enable or inhibit the performance of plant clinics in Nepal. The study used web-based online survey tool to collect primary information. Likert scaling and indexing techniques were used on data analysis. Pretested set of questionnaires were mailed to 209 plant doctors and the response rate was 54.54%. Being ninth country to initiate plant health clinics, Nepal is successful to adapt this novel approach into the existing extension system. It has increased access to plant health services by providing wide range of services at a place. However,limited understanding and only profit motive of local private agro-vet and input dealers has created some biased-understanding and un-trust with clinic organizers. This SWOT analysis clearly spells the scope of plant clinics to fulfill the gap between farmers need and existing services provided by public extension system.Journal of the Institute of Agriculture and Animal Science.Vol. 33-34, 2015, page: 137-146

scholarly journals Silica-encapsulated DNA tracers for measuring aerosol distribution dynamics in real-world settings

2021 ◽  
Author(s):  
Anne M Luescher ◽  
Julian Koch ◽  
Wendelin J Stark ◽  
Robert N Grass
Keyword(s):  
Real World ◽  
Complex Dynamics ◽  
Quantitative Polymerase Chain Reaction ◽  
Cost Effective ◽  
Confined Space ◽  
Aerosol Dynamics ◽  
Novel Approach ◽  
Aerosol Distribution ◽  
Wide Range ◽  
Series Of Experiments

Aerosolized particles play a significant role in human health and environmental risk management. The global importance of aerosol-related hazards, such as the circulation of pathogens and high levels of air pollutants, have led to a surging demand for suitable surrogate tracers to investigate the complex dynamics of airborne particles in real-world scenarios. In this study, we propose a novel approach using silica particles with encapsulated DNA (SPED) as a tracing agent for measuring aerosol distribution indoors. In a series of experiments with a portable setup, SPED were successfully aerosolized, re-captured and quantified using quantitative polymerase chain reaction (qPCR). Position-dependency and ventilation effects within a confined space could be shown in a quantitative fashion achieving detection limits below 0.1 ng particles per m3 of sampled air. In conclusion, SPED show promise for a flexible, cost-effective and low-impact characterization of aerosol dynamics in a wide range of settings.

scholarly journals Patterns of tillering and grain production of winter wheat at a wide range of plant densities.

1978 ◽  
Vol 26 (4) ◽  
pp. 383-398 ◽  
Author(s):  
A. Darwinkel
Keyword(s):  
Winter Wheat ◽  
Grain Yield ◽  
Harvest Index ◽  
Plant Density ◽  
Fold Increase ◽  
Grain Production ◽  
Higher Plant ◽  
Grain Number ◽  
Wide Range ◽  
Plant Densities

The effect of plant density on the growth and productivity of the various ear-bearing stems of winter wheat was studied in detail to obtain information on the pattern of grain production of crops grown under field conditions. Strong compensation effects were measured: a 160-fold increase in plant density (5-800 plants/m2) finally resulted in a 3-fold increase in grain yield (282 to 850 g DM/m2). Max. grain yield was achieved at 100 plants/m2, which corresponded to 430 ears/m2 and to about 19 000 grains/m2. At higher plant densities more ears and more grains were produced, but grain yield remained constant. Tillering/plant was largely favoured by low plant densities because these allowed tiller formation to continue for a longer period and a greater proportion of tillers produced ears. However, at higher plant densities more tillers/unit area were formed and, despite a higher mortality, more ears were produced. The productivity of individual ears, from main stems as well as from tillers, decreased with increasing plant density and with later emergence of shoots. In the range from 5 to 800 plants/m2 grain yield/ear decreased from 2.40 to 1.14 g DM. At 800 plants/m2 nearly all ears originated from main stems, but with decreasing plant density tillers contributed increasingly to the number of ears. At 5 plants/m2, there were 23 ears/plant and grain yield/ear ranged from 4.20 (main stem) to 1.86 g DM (late-formed stems). Grain number/ear was reduced at higher densities and on younger stems, because there were fewer fertile spikelets and fewer grains in these spikelets. At the low density of 5 plants/m2, plants developed solitarily and grain yield/ear was determined by the number of grains/ear as well as by grain wt. Above 400 ears/m2, in this experiment reached at 100 plants/m2 and more, grain yield/ear depended solely on grain number, because the wt. of grains of the various stems were similar. The harvest index showed a max. of about 44% at a moderate plant density; at this density nearly max. grain yield was achieved. At low plant densities the harvest index decreased from 45% in main stems to about 36% in late-formed stems. However, no differences in harvest index existed between the various ear-bearing stems if the number of ears exceeded 400/m2. (Abstract retrieved from CAB Abstracts by CABI’s permission)

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