scholarly journals Selective Drivers of Simple Multicellularity

2021 ◽  
Author(s):  
Kai Tong ◽  
G. Ozan Bozdag ◽  
William C. Ratcliff
Keyword(s):  
Synthetic Biology ◽  
Experimental Evolution ◽  
Comparative Biology ◽  
Subsequent Evolution ◽  
Additional Work ◽  
Recent Developments ◽  
The Many

In order to understand the evolution of multicellularity, we must understand how and why selection favors the first steps in this process: the evolution of simple multicellular groups. Multicellularity has evolved many times in independent lineages with fundamentally different ecologies, yet no work has yet systematically examined these diverse selective drivers. Here we review recent developments in systematics, comparative biology, paleontology, synthetic biology, theory, and experimental evolution, highlighting ten selective drivers of simple multicellularity. Our survey highlights the many ecological opportunities available for simple multicellularity, and stresses the need for additional work examining how these first steps impact the subsequent evolution of complex multicellularity.

scholarly journals Toward Experimental Evolution with Giant Vesicles

Life ◽  
2018 ◽  
Vol 8 (4) ◽  
pp. 53 ◽  
Author(s):  
Hironori Sugiyama ◽  
Taro Toyota
Keyword(s):  
Chemical Evolution ◽  
Self Assembly ◽  
Experimental Evolution ◽  
Microfluidic Devices ◽  
Future Perspective ◽  
Cell Models ◽  
Giant Vesicles ◽  
Chemical Models ◽  
Recent Developments ◽  
Oil Emulsions

Experimental evolution in chemical models of cells could reveal the fundamental mechanisms of cells today. Various chemical cell models, water-in-oil emulsions, oil-on-water droplets, and vesicles have been constructed in order to conduct research on experimental evolution. In this review, firstly, recent studies with these candidate models are introduced and discussed with regards to the two hierarchical directions of experimental evolution (chemical evolution and evolution of a molecular self-assembly). Secondly, we suggest giant vesicles (GVs), which have diameters larger than 1 µm, as promising chemical cell models for studying experimental evolution. Thirdly, since technical difficulties still exist in conventional GV experiments, recent developments of microfluidic devices to deal with GVs are reviewed with regards to the realization of open-ended evolution in GVs. Finally, as a future perspective, we link the concept of messy chemistry to the promising, unexplored direction of experimental evolution in GVs.

Diamond Films: Recent Developments in Theory and Practice

MRS Bulletin ◽  
1998 ◽  
Vol 23 (9) ◽  
pp. 28-31 ◽  
Author(s):  
A.M. Stoneham ◽  
I.J. Ford ◽  
P.R. Chalker
Keyword(s):  
Film Growth ◽  
Defect Density ◽  
Diamond Films ◽  
Electrical Contacts ◽  
Film Deposition ◽  
Theory And Practice ◽  
Maximum Effect ◽  
Recent Developments ◽  
Improved Performance ◽  
The Many

The diamond films of the early 1980s presented two quite different challenges. First how could this new form of diamond be exploited technically? Second, how could this clearly nonequilibrium generation of diamond be understood and the understanding be used to maximum effect? We shall be discussing the ideas of theory and modeling, and we will show how they have contributed to the interplay of science and technology.The science of diamond films is the art of beating nature in the use of carbon. Theory gives the understanding to improve this art. One way in which we improve on nature is in new geometries: controlled growth over selected surfaces o surface regions. The coverage, defect density, microstructure, and rate of growth are key issues. Another way to beat nature is controlled doping. Could wmake n-type semiconductors or lasers using diamond films? A third direction might be routes to control interfaces. Grai boundaries and the regions between small, misaligned crystals affect thermal properties and electron emission. Difficulties with electrical contacts may limit the use of diamond films as semiconductors or insulators. Substrate-film adhesion can determine tribological performance.If theory is to play a role in controlling film deposition, we need to understand the role of theory itself. Theory can add value at several distinct levels. At the highest level, modeling has the potential to provide a substitute for experiment, especially when information is needed about behavior at extreme conditions. When the phenomena are very fast or very complex, theory can be used to interpret limited experiments. At a more modest level, even simple quantitative models can illustrate the many processes occurring during film growth. Atomistic theories of this type can identify the rate-determining steps and point to ways of influencing them. Mesoscopic theories, especially combined with macroscopic approaches like elasticity theory, can identify routes to improved performance.

scholarly journals The Many Faces of Astrocytes in Alzheimer's Disease

2021 ◽  
Vol 12 ◽  
Author(s):  
Michael D. Monterey ◽  
Haichao Wei ◽  
Xizi Wu ◽  
Jia Qian Wu
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Research Effort ◽  
Reactive Astrocytes ◽  
Sequencing Technologies ◽  
Recent Developments ◽  
Current Therapies ◽  
Pathological Development ◽  
The Many

Alzheimer's disease (AD) is a progressive neurodegenerative disease and is the most common cause of dementia in an aging population. The majority of research effort has focused on the role of neurons in neurodegeneration and current therapies have limited ability to slow disease progression. Recently more attention has been given to the role of astrocytes in the process of neurodegeneration. Specifically, reactive astrocytes have both advantageous and adverse effects during neurodegeneration. The ability to isolate and depict astrocyte phenotype has been challenging. However, with the recent development of single-cell sequencing technologies researchers are provided with the resource to delineate specific biomarkers associated with reactive astrocytes in AD. In this review, we will focus on the role of astrocytes in normal conditions and the pathological development of AD. We will further review recent developments in the understanding of astrocyte heterogeneity and associated biomarkers. A better understanding of astrocyte contributions and phenotypic changes in AD can ultimately lead to more effective therapeutic targets.

scholarly journals Role of Piezoelectric Elements in Finding the Mechanical Properties of Solid Industrial Materials

2018 ◽  
Vol 8 (10) ◽  
pp. 1737 ◽  
Author(s):  
Arshed Mohammed ◽  
Sallehuddin Haris ◽  
Mohd Nuawi
Keyword(s):  
Mechanical Properties ◽  
State Of The Art ◽  
New Technology ◽  
Material Testing ◽  
Current Status ◽  
Piezoelectric Elements ◽  
Need To Evaluate ◽  
Recent Developments ◽  
The Many

Recent developments in ultrasonic material testing have increased the need to evaluate the current status of the different applications of piezoelectric elements (PEs). This research have reviewed state-of-the-art emerging new technology and the role of PEs in tests for a number of mechanical properties, such as creep, fracture toughness, hardness, and impact toughness, among others. In this field, importance is given to the following variables, namely, (a) values of the natural frequency to PEs, (b) type and dimensions of specimens, and (c) purpose of the tests. All these variables are listed in three tables to illustrate the nature of their differences in these kinds of tests. Furthermore, recent achievements in this field are emphasized in addition to the many important studies that highlight the role of PEs.

scholarly journals Electrophysiology of Syncytial Smooth Muscle

2019 ◽  
Vol 13 ◽  
pp. 117906951882191 ◽  
Author(s):  
Rohit Manchanda ◽  
Shailesh Appukuttan ◽  
Mithun Padmakumar
Keyword(s):  
Smooth Muscle ◽  
Action Potentials ◽  
Signal Analysis ◽  
Computational Models ◽  
Vas Deferens ◽  
Contractile Activity ◽  
Smooth Muscles ◽  
Biophysical Analysis ◽  
Recent Developments ◽  
The Many

As in other excitable tissues, two classes of electrical signals are of fundamental importance to the functioning of smooth muscles: junction potentials, which arise from neurotransmission and represent the initiation of excitation (or in some instances inhibition) of the tissue, and spikes or action potentials, which represent the accomplishment of excitation and lead on to contractile activity. Unlike the case in skeletal muscle and in neurons, junction potentials and spikes in smooth muscle have been poorly understood in relation to the electrical properties of the tissue and in terms of their spatiotemporal spread within it. This owes principally to the experimental difficulties involved in making precise electrical recordings from smooth muscles and also to two inherent features of this class of muscle, ie, the syncytial organization of its cells and the distributed innervation they receive, which renders their biophysical analysis problematic. In this review, we outline the development of hypotheses and knowledge on junction potentials and spikes in syncytial smooth muscle, showing how our concepts have frequently undergone radical changes and how recent developments hold promise in unraveling some of the many puzzles that remain. We focus especially on computational models and signal analysis approaches. We take as illustrative examples the smooth muscles of two organs with distinct functional characteristics, the vas deferens and urinary bladder, while also touching on features of electrical functioning in the smooth muscles of other organs.

scholarly journals Angular momentum transport in accretion disks: a hydrodynamical perspective

2019 ◽  
Vol 82 ◽  
pp. 391-413 ◽  
Author(s):  
S. Fromang ◽  
G. Lesur
Keyword(s):  
Angular Momentum ◽  
Accretion Disk ◽  
Accretion Disks ◽  
Dynamical Evolution ◽  
Theoretical Work ◽  
Momentum Transport ◽  
Angular Momentum Transport ◽  
Recent Developments ◽  
The Many ◽  
The Universe

The radial transport of angular momentum in accretion disk is a fundamental process in the universe. It governs the dynamical evolution of accretion disks and has implications for various issues ranging from the formation of planets to the growth of supermassive black holes. While the importance of magnetic fields for this problem has long been demonstrated, the existence of a source of transport solely hydrodynamical in nature has proven more difficult to establish and to quantify. In recent years, a combination of results coming from experiments, theoretical work and numerical simulations has dramatically improved our understanding of hydrodynamically mediated angular momentum transport in accretion disk. Here, based on these recent developments, we review the hydrodynamical processes that might contribute to transporting angular momentum radially in accretion disks and highlight the many questions that are still to be answered.

scholarly journals Cell-Free Synthetic Biology Platform for Engineering Synthetic Biological Circuits and Systems

2019 ◽  
Vol 2 (2) ◽  
pp. 39 ◽  
Author(s):  
Dohyun Jeong ◽  
Melissa Klocke ◽  
Siddharth Agarwal ◽  
Jeongwon Kim ◽  
Seungdo Choi ◽  
...  
Keyword(s):  
Synthetic Biology ◽  
Free Expression ◽  
Dna Nanostructures ◽  
Expression Systems ◽  
Natural Systems ◽  
The Past ◽  
Current Cell ◽  
Recent Developments ◽  
Biological Circuits

Synthetic biology integrates diverse engineering disciplines to create novel biological systems for biomedical and technological applications. The substantial growth of the synthetic biology field in the past decade is poised to transform biotechnology and medicine. To streamline design processes and facilitate debugging of complex synthetic circuits, cell-free synthetic biology approaches has reached broad research communities both in academia and industry. By recapitulating gene expression systems in vitro, cell-free expression systems offer flexibility to explore beyond the confines of living cells and allow networking of synthetic and natural systems. Here, we review the capabilities of the current cell-free platforms, focusing on nucleic acid-based molecular programs and circuit construction. We survey the recent developments including cell-free transcription–translation platforms, DNA nanostructures and circuits, and novel classes of riboregulators. The links to mathematical models and the prospects of cell-free synthetic biology platforms will also be discussed.

scholarly journals The Neutral Envelopes of Planetary Nebulae: Molecules and H I

1993 ◽  
Vol 155 ◽  
pp. 147-154 ◽  
Author(s):  
P.J. Huggins
Keyword(s):  
Chemical Properties ◽  
Planetary Nebulae ◽  
Physical And Chemical Properties ◽  
Agb Stars ◽  
Subsequent Evolution ◽  
Neutral Gas ◽  
Recent Developments ◽  
Molecular Lines ◽  
Physical And Chemical ◽  
And Chemical Properties

This paper summarizes recent developments in the study of planetary nebulae using observations of molecular lines and the 21 cm line of H I. The observations reveal that many planetary nebulae are surrounded by envelopes of neutral gas, whose mass often exceeds that of the ionized nebulae. They also provide valuable information on the physical and chemical properties of the envelopes, their structure, and kinematics. The neutral envelopes firmly link the formation of planetary nebulae with the mass loss by AGB stars, and can play an important role in the subsequent evolution of the nebulae.

scholarly journals The many roads to and from multicellularity

2019 ◽  
Vol 71 (11) ◽  
pp. 3247-3253 ◽  
Author(s):  
Karl J Niklas ◽  
Stuart A Newman
Keyword(s):  
Common Ancestor ◽  
Cell Attachment ◽  
Terrestrial Ecosystems ◽  
Life Forms ◽  
Last Common Ancestor ◽  
Physiological Mechanisms ◽  
Multiple Origins ◽  
Recent Developments ◽  
The Many ◽  
Multicellular Organisms

Abstract The multiple origins of multicellularity had far-reaching consequences ranging from the appearance of phenotypically complex life-forms to their effects on Earth’s aquatic and terrestrial ecosystems. Yet, many important questions remain. For example, do all lineages and clades share an ancestral developmental predisposition for multicellularity emerging from genomic and biophysical motifs shared from a last common ancestor, or are the multiple origins of multicellularity truly independent evolutionary events? In this review, we highlight recent developments and pitfalls in understanding the evolution of multicellularity with an emphasis on plants (here defined broadly to include the polyphyletic algae), but also draw upon insights from animals and their holozoan relatives, fungi and amoebozoans. Based on our review, we conclude that the evolution of multicellular organisms requires three phases (origination by disparate cell–cell attachment modalities, followed by integration by lineage-specific physiological mechanisms, and autonomization by natural selection) that have been achieved differently in different lineages.

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