scholarly journals Opposing Pressures of Speed and Efficiency Guide the Evolution of Molecular Machines

2019 ◽  
Vol 36 (12) ◽  
pp. 2813-2822 ◽  
Author(s):  
Jason A Wagoner ◽  
Ken A Dill
Keyword(s):  
Degrees Of Freedom ◽  
Molecular Machines ◽  
The Other ◽  
Ion Pumps ◽  
Dynamical Models ◽  
Performance Properties ◽  
Optimal Balance ◽  
Biomolecular Motors ◽  
Biological Actions

Abstract Many biomolecular machines need to be both fast and efficient. How has evolution optimized these machines along the tradeoff between speed and efficiency? We explore this question using optimizable dynamical models along coordinates that are plausible evolutionary degrees of freedom. Data on 11 motors and ion pumps are consistent with the hypothesis that evolution seeks an optimal balance of speed and efficiency, where any further small increase in one of these quantities would come at great expense to the other. For FoF1-ATPases in different species, we also find apparent optimization of the number of subunits in the c-ring, which determines the number of protons pumped per ATP synthesized. Interestingly, these ATPases appear to more optimized for efficiency than for speed, which can be rationalized through their key role as energy transducers in biology. The present modeling shows how the dynamical performance properties of biomolecular motors and pumps may have evolved to suit their corresponding biological actions.

HPLC Screening of Bioactives Compounds and Antioxidant Capacity of Different Hypericum Species

2018 ◽  
Vol 69 (2) ◽  
pp. 305-309 ◽  
Author(s):  
Daniela Gitea ◽  
Simona Vicas ◽  
Manuel Alexandru Gitea ◽  
Sebastian Nemeth ◽  
Delia Mirela Tit ◽  
...  
Keyword(s):  
Antioxidant Capacity ◽  
Methanol Extract ◽  
Antioxidant Properties ◽  
Polyphenolic Compounds ◽  
The Other ◽  
The North ◽  
Western Area ◽  
North Western ◽  
Hypericum Species ◽  
Biological Actions

Our study compares the content in polyphenolic compounds and hypericin, in four species of Hypericum - H. perforatum L., H. maculatum Cr., H. hirsutum L., H. tetrapterum Fr. (syn. Hypericumacutum Mnch.) harvested from spontaneous flora in the north-western area of Transylvania, Romania. These species represent an important source of such compounds with different biological actions. After making the extracts, they were subjected to HPLC-SM analysis. The presence of rutoside in the largest amount (462.82 mg %) in the H. perforatum extract was observed, this containing most of the flavonoid heterosides. For the species H. maculatum, the presence in a much higher amount of the hyperoside (976.36 mg %) is characteristic compared to the other species. Quercetol is the best represented of the flavonoid aglycons, its concentration being the highest in H. hirsutum (659.66 mg %). The hypericin content ranges from 0.2171 g % in the H. tetrapterum extract, to 0.0314 g % in the methanol extract of H. maculatum.The highest antioxidant properties measured by FRAP method were recorded in the case of H. perforatum and H. maculatum.

Footbridges as an important part of a system: the context as an experience

2021 ◽  
Author(s):  
Toon Maas ◽  
Mohamad Tuffaha ◽  
Laurent Ney
Keyword(s):  
Design Process ◽  
Degrees Of Freedom ◽  
The Other ◽  
Infrastructure Projects ◽  
Good Design ◽  
Cultural Processes ◽  
The Relationship

<p>“A bridge has to be designed”. Every bridge is the exploration of all degrees of a freedom of a project: the context, cultural processes, technology, engineering and industrial skills. A successful bridge aims to dialogue with these degrees of freedom to achieve a delicate equilibrium, one that invites the participation of its users and emotes new perceptions for its viewers. In short, a good design “makes the bridge talk.”</p><p>Too often, the bridge, as an object, is reduced to its functionality. Matters of perceptions and experiences of the users are often not considered in the design process; they are relegated to levels of chance or treated as simple decorative matter. The longevity of infrastructure projects, in general, and bridges, in particular, highlights the deficiencies of such an approach. The framework to design bridges must include historical, cultural, and experiential dimensions. Technology and engineering are of paramount importance but cannot be considered as “an end in themselves but a means to an end”. This paper proposes to discuss three projects by Ney &amp; Partners that illustrate such a comprehensive exploration approach to footbridge design: the Poissy and Albi crossings and the Tintagel footbridge.</p><p>The footbridges of Poissy and Albi dialogue most clearly with their historical contexts, reconfiguring the relationship between old and new in the materiality and typology use. In Tintagel, legend replaces history. Becoming a metaphor for the void it crosses, the Tintagel footbridge illustrates the delicate dialogue of technology and engineering on one side and imagination and experience on the other.</p>

Miniaturized Dual-Band Bandpass Filter Using Embedded Dual-Mode Resonator with Controllable Bandwidths

Frequenz ◽  
2016 ◽  
Vol 70 (9-10) ◽  
Author(s):  
Chuanming Zhu ◽  
Jin Xu ◽  
Wei Kang ◽  
Zhenxin Hu ◽  
Wen Wu
Keyword(s):  
Insertion Loss ◽  
Degrees Of Freedom ◽  
Bandpass Filter ◽  
The Other ◽  
Dual Band ◽  
Dual Mode ◽  
Transmission Zeros ◽  
Low Insertion Loss ◽  
Multiple Transmission ◽  
Mode Resonator

AbstractIn this paper, a miniaturized dual-band bandpass filter (DB-BPF) using embedded dual-mode resonator (DMR) with controllable bandwidths is proposed. Two passbands are generated by two sets of resonators operating at two different frequencies. One set of resonators is utilized not only as the resonant elements that yield the lower passband, but also as the feeding structures with source-load coupling to excite the other to produce the upper passband. Sufficient degrees of freedom are achieved to control the center frequencies and bandwidths of two passbands. Moreover, multiple transmission zeros (TZs) are created to improve the passband selectivity of the filter. The design of the filter has been demonstrated by the measurement. The filter features not only miniaturized circuit sizes, low insertion loss, independently controllable central frequencies, but also controllable bandwidths and TZs.

A Robotic Cell for Embedding Prefabricated Components in Extrusion-Based Additive Manufacturing

2020 ◽  
Author(s):  
Yeo Jung Yoon ◽  
Oswin G. Almeida ◽  
Aniruddha V. Shembekar ◽  
Satyandra K. Gupta
Keyword(s):  
Additive Manufacturing ◽  
Degrees Of Freedom ◽  
Robotic Manipulators ◽  
The Other ◽  
Robotic Arm ◽  
Robotic Cell ◽  
Material Extrusion ◽  
Surface Polishing ◽  
Pick And Place ◽  
6 Degrees Of Freedom

Abstract By attaching a material extrusion system to a robotic arm, we can deposit materials onto complex surfaces. Robotic manipulators can also maximize the task utility by performing other tasks such as assembly or surface polishing when they are not in use for the AM process. We present a robotic cell for embedding prefabricated components in extrusion-based AM. The robotic cell consists of two 6 degrees of freedom (DOF) robots, an extrusion system, and a gripper. One robot is used for printing a part, and the other robot takes a support role to pick and place the prefabricated component and embed it into the part being printed. After the component is embedded, AM process resumes, and the material is deposited onto the prefabricated components and previously printed layers. We illustrate the capabilities of the system by fabricating three objects.

A Family of 3-DOF Translational Parallel Manipulators1

2003 ◽  
Vol 125 (2) ◽  
pp. 302-307 ◽  
Author(s):  
Marco Carricato ◽  
Vincenzo Parenti-Castelli
Keyword(s):  
Degrees Of Freedom ◽  
Translational Motion ◽  
Parallel Manipulators ◽  
Geometric Interpretation ◽  
The Other ◽  
Six Degrees Of Freedom ◽  
Revolute Joints ◽  
Rotational Degrees Of Freedom

This article addresses parallel manipulators with fewer than six degrees of freedom, whose use may prove valuable in those applications in which a higher mobility is uncalled for. In particular, a family of 3-dof manipulators containing only revolute joints or at the most revolute and prismatic ones is studied. Design and assembly conditions sufficient to provide the travelling platform with a pure translational motion are determined and two sub-families that fulfill the imposed constraint are found: one is already known in the literature, while the other is original. The new architecture does not exhibit rotation singularities, i.e., configurations in which the platform gains rotational degrees of freedom. A geometric interpretation of the translation singularities is provided.

Total Flexibility in Forming Technology by Servo Presses

2014 ◽  
Vol 907 ◽  
pp. 99-112 ◽  
Author(s):  
Jörg Avemann ◽  
Stefan Calmano ◽  
Sebastian Schmitt ◽  
Peter Groche
Keyword(s):  
Mass Production ◽  
Degrees Of Freedom ◽  
Sheet Thickness ◽  
The Other ◽  
Adaptive Control System ◽  
High Productivity ◽  
Forming Technology ◽  
Bending Process ◽  
Product And Process ◽  
Free Bending

In forming technology, uncertainty can arouse from fluctuations in demand scenarios on one hand and in properties of semi-finished parts on the other. These technologies are usually characterized by a high productivity in mass production. However, high development efforts and investment costs for processes and machines lead to a rigid product and process spectrum. One approach to encounter these uncertainties is the introduction of flexibility into forming technologies by enlarging the number of degrees of freedom without drastically reducing productivity. The 3D Servo Press fulfils the mentioned requirements by exceeding free ram motion of conventional servo presses by two rotational ram DoFs. The adaptive control system coordinates the machine motion and controls product properties by model-based algorithms. Possibilities of this approach are demonstrated in a free bending process of a heat dissipater, resulting in uniform product quality despite variations in material, sheet thickness and desired geometry.

Inverse Static Analysis of a Planar System With Spiral Springs

2000 ◽  
Author(s):  
Marco Carricato ◽  
Joseph Duffy ◽  
Vincenzo Parenti-Castelli
Keyword(s):  
Static Analysis ◽  
External Load ◽  
Degrees Of Freedom ◽  
The Other ◽  
Linear Functions ◽  
State Variables ◽  
Planar System ◽  
Equilibrium Configurations ◽  
Solving Equations ◽  
The One

Abstract In this article the inverse static analysis of a two degrees of freedom planar mechanism equipped with spiral springs is presented. Such analysis aims to detect the entire set of equilibrium configurations of the mechanism once the external load is assigned. While on the one hand the presence of flexural pivots represents a novelty, on the other it extremely complicates the problem, since it brings the two state variables in the solving equations to appear as arguments of both trigonometric and linear functions. The proposed procedure eliminates one variable and leads to write two equations in one unknown only. The union of the root sets of such equations constitutes the global set of solutions of the problem. Particular attention has been reserved to the analysis of the “reliability” of the final equations: it has been sought the existence of critical situations, in which the solving equations hide solutions or yield false ones. A numerical example is provided. Also, in Appendix it is shown a particular design of the mechanism that offers computational advantages.

Lipopolysaccharide: a tool and target in enterobacterial vaccine development

2008 ◽  
Vol 389 (5) ◽  
Author(s):  
Gábor Nagy ◽  
Tibor Pál
Keyword(s):  
Immune Response ◽  
Protective Immunity ◽  
Vaccine Development ◽  
The Other ◽  
Live Vaccine Strain ◽  
Gram Negative Bacteria ◽  
Gram Negative ◽  
Vaccination Strategies ◽  
Optimal Balance ◽  
Alternative Approaches

AbstractLipopolysaccharide (LPS) is an essential component of Gram-negative bacteria. While mutants exhibiting truncated LPS molecules are usually over-attenuated, alternative approaches that affect the extent or timing of LPS expression, as well as its modification may establish the optimal balance for a live vaccine strain of sufficient attenuation and retained immunogenicity. On the other hand, a specific immune response to LPS molecules in itself is capable of conferring protective immunity to certain enterobacterial pathogens. Therefore, purified LPS derivatives could be used as parenteral vaccines. This review summarizes various LPS-based vaccination strategies, as well as approaches that utilize LPS mutants as whole-cell vaccines.

The Conceptual Design of Differential Mechanisms

2013 ◽  
Vol 284-287 ◽  
pp. 973-978
Author(s):  
Chia Chun Chu
Keyword(s):  
Conceptual Design ◽  
Design Process ◽  
Degrees Of Freedom ◽  
Geometric Constraints ◽  
The Other ◽  
Design Approach ◽  
Process Step ◽  
Two Degrees Of Freedom ◽  
Number Synthesis

The purpose of this paper is to present a design approach based on the geometric constraints of joints for synthesizing differential mechanisms with two degrees-of-freedom, including some mechanisms with the same functions but distinct structures. The concept of virtual axes is presented. And, there are five steps in the design process. Step 1 is to decide fundamental entities by the properties of existing mechanisms and the technique of number synthesis, and 10 suitable fundamental entities of differential mechanisms are available. Step 2 is to compose geometric constraints, and 14 items are obtained. Step 3 is to compose links, and 15 items are derived. Step 4 is to assign fixed constraints for inputs or outputs, and 15 results are found. The final step is to particularize the obtained events by the properties of existing mechanisms and the structures of fundamental entities. As a result, 8 feasible results for differential mechanisms with two degrees-of-freedom and two basic loops are obtained in which 2 are existing designs and the other 6 are novel.

Synthesis of Seven-Link Mechanisms

1973 ◽  
Vol 95 (2) ◽  
pp. 533-540 ◽  
Author(s):  
D. Kohli ◽  
A. H. Soni
Keyword(s):  
Closed Form ◽  
Nonlinear Equations ◽  
Degrees Of Freedom ◽  
The Other ◽  
Linear Superposition ◽  
Two Degrees Of Freedom ◽  
Closed Form Solutions ◽  
Highly Nonlinear ◽  
Principle Of Linear Superposition

The mechanisms derived from the seven-link chains with five links in their two loops and having two degrees of freedom are examined for six synthesis problems. Using displacement matrices, closed form synthesis equations are derived. It is shown that three synthesis problems may be solved using the principle of linear superposition, and closed form solutions may be obtained. The other three synthesis problems involve highly nonlinear equations and must be solved numerically.

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