scholarly journals Generalized Single Stage Class C Amplifier: Analysis from the Viewpoint of Chaotic Behavior

2020 ◽  
Vol 10 (15) ◽  
pp. 5025 ◽  
Author(s):  
Jiri Petrzela
Keyword(s):  
Chaotic Behavior ◽  
Building Blocks ◽  
Cubic Polynomial ◽  
Signal Path ◽  
Class C ◽  
Lc Tank ◽  
High Degree ◽  
Bias Point ◽  
Stage Class ◽  
Simple Network

This paper briefly describes a recent discovery that occurred during the study of the simplest mathematical model of a class C amplifier with a bipolar transistor. It is proved both numerically and experimentally that chaos can be observed in this simple network structure under three conditions: (1) the transistor is considered non-unilateral, (2) bias point provides cubic polynomial feedforward and feedback transconductance, and (3) the LC tank has very high resonant frequency. Moreover, chaos is generated by an autonomous class C amplifier; i.e., an isolated system without a driving force is analyzed. By the connection of a harmonic input signal, much more complex behavior can be observed. Additionally, due to the high degree of generalization of the amplifier cell, similar fundamental circuits can be ordinarily found as subparts of typical building blocks of a radio frequency signal path.

Microfluidic Parallel Form Mixer Utilizing Chaotic Electric Field

2007 ◽  
Vol 364-366 ◽  
pp. 449-453
Author(s):  
Her Terng Yau ◽  
Chieh Li Chen ◽  
Ching Chang Cho
Keyword(s):  
Electric Field ◽  
Chaotic Behavior ◽  
Channel Length ◽  
Mixing Efficiency ◽  
Successful Operation ◽  
Number Systems ◽  
Flow Mixing ◽  
Reagent Consumption ◽  
Electric Filed ◽  
High Degree

The past few years, have witnessed a rapid increase in the application of microfluidic devices to chemical and biological analyses. These devices offer significant advantages over their traditional counterparts, including reduced reagent consumption, a more rapid analysis and a significant improvement in performance. Species mixing is a fundamentally important aspect of these devices since it is this mixing which generates the biochemical reactions necessary for their successful operation. Many microfluidic applications require the mixing of reagents, but efficient mixing in these laminar (i.e., low Reynolds number) systems are typically difficult. Instead of using complex geometries and/or relatively long channels, an electric field is applied to drive flow mixing in microchannels. Generally, the fluid is driven by the application of an external periodic AC electric field. However, the chaotic AC electric filed is never used to drive flow mixing in microchannels. Chaotic behavior is a very interesting nonlinear effect. In some physical systems, chaos is a beneficial feature as it enhances mixing in chemical reactions. This paper presents a numerical investigation of electrokinetically-driven flow mixing in microchannels with chaotic electric field. The simulation results show that the application of a chaotic external field enables a reduction in the mixing channel length and a high degree of mixing efficiency. It is shown that a mixing performance as high as 90% can be achieved by chaotic external electric field.

The Oxford Handbook of Inflection

2015 ◽  
Keyword(s):  
Final Section ◽  
Characteristic Property ◽  
Building Blocks ◽  
The Third ◽  
The Pacific ◽  
Word Forms ◽  
Practical Standpoint ◽  
Important Object ◽  
Paradigmatic Structure ◽  
High Degree

Inflection is the expression of grammatical information through changes in word forms. This confrontation between general principles of syntactic organization and the often idiosyncratic properties of words has brought about systems whose properties—among them an often high degree of complexity—are an important object of investigation in their own right. Because it is something that many languages happily do without, inflection has a curious and often contentious status within linguistics. But even so, there is a fascinating and well-delimited set of facts out there to be explored, for which this handbook will be a guide. The volume is made up of twenty-four chapters, which together take a theoretically ecumenical approach, with particular attention paid to draw the examples from a wide variety of languages. The first section covers the fundamental building blocks of inflectional form and content: morphemes, features, and means of exponence. The second section focuses on what is probably the most characteristic property of inflectional systems, paradigmatic structure, and the non-trivial nature of the mapping between function and form. The third section covers change and variation over time, and the fourth section covers computational issues from a theoretical and practical standpoint. Section five addresses psycholinguistic questions. The final section is devoted to sketches of individual inflectional systems, illustrating a range of typological possibilities across a genetically diverse set of languages from Africa, Asia and the Pacific, Australia, Europe, and South America.

scholarly journals Structural Characterization of an S-enantioselective Imine Reductase from Mycobacterium Smegmatis

Biomolecules ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 1130
Author(s):  
Timo Meyer ◽  
Nadine Zumbrägel ◽  
Christina Geerds ◽  
Harald Gröger ◽  
Hartmut H. Niemann
Keyword(s):  
Substrate Specificity ◽  
Active Site ◽  
Mycobacterium Smegmatis ◽  
Catalytic Mechanism ◽  
Building Blocks ◽  
Secondary Amines ◽  
Hydrophobic Amino Acids ◽  
High Degree

NADPH-dependent imine reductases (IREDs) are enzymes capable of enantioselectively reducing imines to chiral secondary amines, which represent important building blocks in the chemical and pharmaceutical industry. Since their discovery in 2011, many previously unknown IREDs have been identified, biochemically and structurally characterized and categorized into families. However, the catalytic mechanism and guiding principles for substrate specificity and stereoselectivity remain disputed. Herein, we describe the crystal structure of S-IRED-Ms from Mycobacterium smegmatis together with its cofactor NADPH. S-IRED-Ms belongs to the S-enantioselective superfamily 3 (SFam3) and is the first IRED from SFam3 to be structurally described. The data presented provide further evidence for the overall high degree of structural conservation between different IREDs of various superfamilies. We discuss the role of Asp170 in catalysis and the importance of hydrophobic amino acids in the active site for stereospecificity. Moreover, a separate entrance to the active site, potentially functioning according to a gatekeeping mechanism regulating access and, therefore, substrate specificity is described.

scholarly journals BRICK v0.1, a simple, accessible, and transparent model framework for climate and regional sea-level projections

2017 ◽  
Author(s):  
Tony E. Wong ◽  
Alexander Bakker ◽  
Kelsey Ruckert ◽  
Patrick Applegate ◽  
Aimée Slangen ◽  
...  
Keyword(s):  
Simple Model ◽  
Sea Level ◽  
Flood Risk ◽  
Building Blocks ◽  
Computationally Efficient ◽  
Model Framework ◽  
Sea Levels ◽  
Model Components ◽  
High Degree ◽  
Simple Models

Abstract. Simple models can play pivotal roles in the quantification and framing of uncertainties surrounding climate change and sea-level rise. They are computationally efficient, transparent, and easier to reproduce. These qualities make simple models useful for uncertainty quantification and risk characterization. Simple model codes are increasingly distributed as open source, as well as actively shared and guided. Alas, computer codes used in the geosciences can often be hard to access, run, modify (e.g., with regards to assumptions and model components), and review. Here, we introduce a simple model framework for projections of global mean temperatures as well as regional sea levels and coastal flood risk (BRICK: Building blocks for Relevant Ice and Climate Knowledge). The BRICK model framework is written in R and Fortran and aims to help mitigate these issues, while maintaining a high degree of computational efficiency. We demonstrate the flexibility of this framework through simple model intercomparison experiments. Furthermore, we demonstrate that BRICK is suitable for risk assessment applications by using a didactic example in local flood risk management.

A REUSE-ORIENTED WORKFLOW DEFINITION LANGUAGE

2003 ◽  
Vol 12 (01) ◽  
pp. 1-36 ◽  
Author(s):  
MARIE JOSÉ BLIN ◽  
JACQUES WAINER ◽  
CLAUDIA BAUZER MEDEIROS
Keyword(s):  
Programming Languages ◽  
Building Blocks ◽  
Database Systems ◽  
Exception Handling ◽  
Control Flow ◽  
New Formalism ◽  
Definition Of ◽  
High Level ◽  
And Control ◽  
High Degree

This paper presents a new formalism for workflow process definition, which combines research in programming languages and in database systems. This formalism is based on creating a library of workflow building blocks, which can be progressively combined and nested to construct complex workflows. Workflows are specified declaratively, using a simple high level language, which allows the dynamic definition of exception handling and events, as well as dynamically overriding workflow definition. This ensures a high degree of flexibility in data and control flow specification, as well as in reuse of workflow specifications to construct other workflows. The resulting workflow execution environment is well suited to supporting cooperative work.

FIRST LYAPUNOV VALUE AND BIFURCATION BEHAVIOR OF SPECIFIC CLASS OF THREE-DIMENSIONAL SYSTEMS

2004 ◽  
Vol 14 (08) ◽  
pp. 2811-2823 ◽  
Author(s):  
SVETOSLAV NIKOLOV
Keyword(s):  
Dynamic Systems ◽  
Chaotic Behavior ◽  
Three Dimensional ◽  
Analytical Formula ◽  
Specific Class ◽  
Third Order ◽  
Cubic Polynomial ◽  
Route To Chaos ◽  
Boundary Of Stability ◽  
Bifurcation Behavior

This paper presents a study of the behavior of a special class of 3D dynamic systems (i.e. RHS of the third-order equation is a cubic polynomial), using Lyapunov–Andronov's theory. Considering the general case, we find a new analytical formula for the first Lyapunov's value at the boundary of stability. It enables one to study in detail the bifurcation behavior (and the route to chaos, in particular) of dynamic systems of the above type. We check the validity of our analytical results on the first Lyapunov's value by studying the route to chaos of two 3D dynamic systems with proved chaotic behavior. These are Chua's and Rucklidge's systems. Considering their route to chaos, we find new results.

scholarly journals Comparative Metabolite and Gene Expression Analyses in Combination With Gene Characterization Revealed the Patterns of Flavonoid Accumulation During Cistus creticus subsp. creticus Fruit Development

2021 ◽  
Vol 12 ◽  
Author(s):  
Neda Aničić ◽  
Efstathia Patelou ◽  
Antigoni Papanikolaou ◽  
Anthi Kanioura ◽  
Camilla Valdesturli ◽  
...  
Keyword(s):  
Transcription Factors ◽  
Fruit Development ◽  
Expression Patterns ◽  
Building Blocks ◽  
Bioactive Metabolites ◽  
Fruit Maturation ◽  
Biosynthetic Genes ◽  
Positive Correlations ◽  
High Degree ◽  
Cistus Creticus

Cistus creticus L. subsp. creticus (rockrose) is a shrub widespread in Greece and the Mediterranean basin and has been used in traditional medicine as herb tea for colds, for healing and digestive hitches, for the treatment of maladies, as perfumes, and for other purposes. Compounds from its flavonoid fraction have recently drawn attention due to antiviral action against influenza virus and HIV. Although several bioactive metabolites belonging to this group have been chemically characterized in the leaves, the genes involved in their biosynthesis in Cistus remain largely unknown. Flavonoid metabolism during C. creticus fruit development was studied by adopting comparative metabolomic and transcriptomic approaches. The present study highlights the fruit of C. creticus subsp. creticus as a rich source of flavonols, flavan-3-ols, and proanthocyanidins, all of which displayed a decreasing trend during fruit development. The majority of proanthocyanidins recorded in Cistus fruit are B-type procyanidins and prodelphinidins, while gallocatechin and catechin are the dominant flavan-3-ols. The expression patterns of biosynthetic genes and transcription factors were analyzed in flowers and throughout three fruit development stages. Flavonoid biosynthetic genes were developmentally regulated, showing a decrease in transcript levels during fruit maturation. A high degree of positive correlations between the content of targeted metabolites and the expression of biosynthetic genes indicated the transcriptional regulation of flavonoid biosynthesis during C. creticus fruit development. This is further supported by the high degree of significant positive correlations between the expression of biosynthetic genes and transcription factors. The results suggest that leucoanthocyanidin reductase predominates the biosynthetic pathway in the control of flavan-3-ol formation, which results in catechin and gallocatechin as two of the major building blocks for Cistus proanthocyanidins. Additionally, there is a decline in ethylene production rates during non-climacteric Cistus fruit maturation, which coincides with the downregulation of the majority of flavonoid- and ethylene-related biosynthetic genes and corresponding transcription factors as well as with the decline in flavonoid content. Finally, functional characterization of a Cistus flavonoid hydroxylase (F3′5′H) was performed for the first time.

scholarly journals Dendron-Polymer Hybrids as Tailorable Coronae of Single-Walled Carbon Nanotube

2021 ◽  
Author(s):  
Verena Wulf ◽  
Gadi Slor ◽  
Parul Rathee ◽  
Roey J. Amir ◽  
Gili Bisker
Keyword(s):  
Rational Design ◽  
Near Infrared ◽  
Fluorescence Emission ◽  
Building Blocks ◽  
Single Walled Carbon Nanotube ◽  
Single Walled Carbon ◽  
Amphiphilic Macromolecules ◽  
End Groups ◽  
High Degree ◽  
Walled Carbon Nanotubes

Single-walled carbon nanotubes (SWCNTs), non-covalently functionalized by synthetic polymers, find widespread applications including sensing and imaging. Identifying new amphiphiles with interchangeable building blocks that can form unique coronae around the SWCNT, customized for a specific application, is thus of great interest. We present polymer-dendron hybrids, composed of hydrophobic dendrons and hydrophilic polyethylene glycol (PEG), as amphiphilic macromolecules with high degree of structural freedom, for suspending SWCNTs in aqeous solution. Based on a set of four PEG-dendrons differing in their dendritic end-groups, we show thst differences in the chemical structure of the hydrophobic end-groups control the interactions of the PEG-dendrons with the SWCNT-surface. These interactions led to differences in the intrinsic near-infrared fluorescence emission of the SWCNTs and affected the PEG-dendron susceptibility to enzymatic degradation, which was monitored by the SWCNT fluorescent signal. Our findings open new avenues for rational design of SWCNT functionalization, and optical sensing of enzymatic activity<br>

scholarly journals Coding Synthetic Chemistry Strategies into Bacterial Designer Cells

2021 ◽  
Author(s):  
Yu-Chang Liu ◽  
Zhong-Liu Wu ◽  
Jan Deska
Keyword(s):  
Building Blocks ◽  
Cell System ◽  
Synthetic Chemistry ◽  
Bacterial Host ◽  
Whole Cell ◽  
Isolation And Purification ◽  
Platform Chemicals ◽  
Natural Enzyme ◽  
High Degree

<p>Following a synthetic chemistry blueprint for the valorization of lignocellulosic platform chemicals, this study showcases a so far unprecedented approach to implement non-natural enzyme modules in vivo. For the design of a novel functional whole cell tool, two purely abiotic transformations were incorporated into a recombinant bacterial host that allows production of complex lactone building blocks. This whole cell system streamlines the synthetic cascade, eliminates isolation and purification steps, and provides a high degree stereoselectivity that has so far been elusive in the chemical methodology.</p>

scholarly journals Coding Synthetic Chemistry Strategies into Bacterial Designer Cells

2021 ◽  
Author(s):  
Yu-Chang Liu ◽  
Zhong-Liu Wu ◽  
Jan Deska
Keyword(s):  
Building Blocks ◽  
Cell System ◽  
Synthetic Chemistry ◽  
Bacterial Host ◽  
Whole Cell ◽  
Isolation And Purification ◽  
Platform Chemicals ◽  
Natural Enzyme ◽  
High Degree

<p>Following a synthetic chemistry blueprint for the valorization of lignocellulosic platform chemicals, this study showcases a so far unprecedented approach to implement non-natural enzyme modules in vivo. For the design of a novel functional whole cell tool, two purely abiotic transformations were incorporated into a recombinant bacterial host that allows production of complex lactone building blocks. This whole cell system streamlines the synthetic cascade, eliminates isolation and purification steps, and provides a high degree stereoselectivity that has so far been elusive in the chemical methodology.</p>

Sign in / Sign up

Export Citation Format

Share Document