scholarly journals Tracking single particle rotation: probing dynamics in four dimensions

2015 ◽  
Vol 7 (17) ◽  
pp. 7020-7028 ◽  
Author(s):  
S. M. Anthony ◽  
Y. Yu
Keyword(s):  
Temporal Resolution ◽  
Single Particle ◽  
Complex Dynamics ◽  
Biological Processes ◽  
Direct Visualization ◽  
Small Particles ◽  
Particle Rotation ◽  
Four Dimensions ◽  
Powerful Approach

Direct visualization and tracking of small particles at high spatial and temporal resolution provides a powerful approach to probing complex dynamics and interactions in chemical and biological processes.

scholarly journals The Yin and Yang of tumour-derived extracellular vesicles in tumour immunity

2020 ◽  
Author(s):  
Takayoshi Yamauchi ◽  
Toshiro Moroishi
Keyword(s):  
Extracellular Vesicles ◽  
Tumour Progression ◽  
Tumour Microenvironment ◽  
Host Immunity ◽  
Biological Processes ◽  
Small Particles ◽  
Tumour Immunity ◽  
Heterogeneous Nature ◽  
Yin And Yang ◽  
Cellular Components

Abstract Extracellular vesicles (EVs) are small particles that are naturally released from various types of cells. EVs contain a wide variety of cellular components, such as proteins, nucleic acids, lipids and metabolites, which facilitate intercellular communication in diverse biological processes. In the tumour microenvironment, EVs have been shown to play important roles in tumour progression, including immune system–tumour interactions. Although previous studies have convincingly demonstrated the immunosuppressive functions of tumour-derived EVs, some studies have suggested that tumour-derived EVs can also stimulate host immunity, especially in therapeutic conditions. Recent studies have revealed the heterogeneous nature of EVs with different structural and biological characteristics that may account for the divergent functions of EVs in tumour immunity. In this review article, we provide a brief summary of our current understanding of tumour-derived EVs in immune activation and inhibition. We also highlight the emerging utility of EVs in the diagnosis and treatment of cancers and discuss the potential clinical applications of tumour-derived EVs.

scholarly journals Real-Time 3D Single Particle Tracking: Towards Active Feedback Single Molecule Spectroscopy in Live Cells

Molecules ◽  
2019 ◽  
Vol 24 (15) ◽  
pp. 2826 ◽  
Author(s):  
Shangguo Hou ◽  
Courtney Johnson ◽  
Kevin Welsher
Keyword(s):  
Fluorescence Spectroscopy ◽  
Real Time ◽  
Temporal Resolution ◽  
Single Molecule ◽  
Particle Tracking ◽  
Single Particle ◽  
Single Particle Tracking ◽  
Single Molecule Fluorescence ◽  
Single Molecule Fluorescence Spectroscopy ◽  
Active Feedback

Single molecule fluorescence spectroscopy has been largely implemented using methods which require tethering of molecules to a substrate in order to make high temporal resolution measurements. However, the act of tethering a molecule requires that the molecule be removed from its environment. This is especially perturbative when measuring biomolecules such as enzymes, which may rely on the non-equilibrium and crowded cellular environment for normal function. A method which may be able to un-tether single molecule fluorescence spectroscopy is real-time 3D single particle tracking (RT-3D-SPT). RT-3D-SPT uses active feedback to effectively lock-on to freely diffusing particles so they can be measured continuously with up to photon-limited temporal resolution over large axial ranges. This review gives an overview of the various active feedback 3D single particle tracking methods, highlighting specialized detection and excitation schemes which enable high-speed real-time tracking. Furthermore, the combination of these active feedback methods with simultaneous live-cell imaging is discussed. Finally, the successes in real-time 3D single molecule tracking (RT-3D-SMT) thus far and the roadmap going forward for this promising family of techniques are discussed.

scholarly journals Zebrafish and Medaka: Two Teleost Models of T-Cell and Thymic Development

2019 ◽  
Vol 20 (17) ◽  
pp. 4179 ◽  
Author(s):  
Baubak Bajoghli ◽  
Advaita M. Dick ◽  
Annisa Claasen ◽  
Larissa Doll ◽  
Narges Aghaallaei
Keyword(s):  
T Cell ◽  
Molecular Mechanisms ◽  
T Cell Development ◽  
Model Systems ◽  
Biological Processes ◽  
Direct Visualization ◽  
Thymic Development ◽  
The Past ◽  
Shed Light

Over the past two decades, studies have demonstrated that several features of T-cell and thymic development are conserved from teleosts to mammals. In particular, works using zebrafish (Danio rerio) and medaka (Oryzias latipes) have shed light on the cellular and molecular mechanisms underlying these biological processes. In particular, the ease of noninvasive in vivo imaging of these species enables direct visualization of all events associated with these processes, which are, in mice, technically very demanding. In this review, we focus on defining the similarities and differences between zebrafish and medaka in T-cell development and thymus organogenesis; and highlight their advantages as two complementary model systems for T-cell immunobiology and modeling of human diseases.

Change of particle structure of sewage sludges during mechanical and biological processes with regard to the dewatering result

1997 ◽  
Vol 36 (4) ◽  
pp. 293-306 ◽  
Author(s):  
Thomas Nellenschulte ◽  
Rolf Kayser
Keyword(s):  
Total Mass ◽  
High Performance ◽  
Suspended Solids ◽  
Biological Process ◽  
Waste Activated Sludge ◽  
Biological Processes ◽  
Small Particles ◽  
Particle Structure ◽  
Integral Property ◽  
Wastewater Sludges

Particle size seems to be the most important parameter, to describe the dewatering behaviour and result of sludges. But there are many other parameters, which can influence the dewatering result. The dewatering result of a sludge depends on the type of sludge, the mechanical and biological process. Out of the numerous parameters to characterize wastewater sludges five were selected, which describe the properties of the particulate matter. These parameters are the suspended solids (SS), the volatile suspended solids (VSS), the density of the particles (ρ), the fraction of small particles (fines) and a new parameter, called φ-value, which is the ratio of the mass of waste activated sludge to the total mass of sludge. The tested sludges were analysed for the Zeta Potential, but there could not be found a correlation between this parameter and the dewatering result. Combining the parameters in a model led to an overall sludge parameter, the so-called “Integral Property Parameter, fE”. A correlation between the fE-values and the dewatering results of municipal sludges (n = 49) can be found. A proposal was made to transfer the experimental results to a full scale dewatering process with high performance centrifuges.

scholarly journals Small RNA Expression Profiling by High-Throughput Sequencing: Implications of Enzymatic Manipulation

2012 ◽  
Vol 2012 ◽  
pp. 1-15 ◽  
Author(s):  
Fanglei Zhuang ◽  
Ryan T. Fuchs ◽  
G. Brett Robb
Keyword(s):  
High Throughput ◽  
Expression Profiling ◽  
Messenger Rna ◽  
High Throughput Sequencing ◽  
Biological Processes ◽  
Cellular Processes ◽  
Disease States ◽  
Powerful Approach ◽  
Sequencing Library ◽  
Rna Expression Profiling

Eukaryotic regulatory small RNAs (sRNAs) play significant roles in many fundamental cellular processes. As such, they have emerged as useful biomarkers for diseases and cell differentiation states. sRNA-based biomarkers outperform traditional messenger RNA-based biomarkers by testing fewer targets with greater accuracy and providing earlier detection for disease states. Therefore, expression profiling of sRNAs is fundamentally important to further advance the understanding of biological processes, as well as diagnosis and treatment of diseases. High-throughput sequencing (HTS) is a powerful approach for both sRNA discovery and expression profiling. Here, we discuss the general considerations for sRNA-based HTS profiling methods from RNA preparation to sequencing library construction, with a focus on the causes of systematic error. By examining the enzymatic manipulation steps of sRNA expression profiling, this paper aims to demystify current HTS-based sRNA profiling approaches and to aid researchers in the informed design and interpretation of profiling experiments.

An insect glycoprotein: a study of the particles responsible for the resistance of a parasitoid’s egg to the defence reactions of its insect host

1979 ◽  
Vol 205 (1159) ◽  
pp. 271-286 ◽  
Keyword(s):  
Chemical Composition ◽  
Nucleic Acid ◽  
Molecular Mass ◽  
Single Particle ◽  
Physical Structure ◽  
Insect Host ◽  
Small Particles ◽  
The Core ◽  
Structural Subunit ◽  
Defence Reactions

A study has been carried out of the chemical composition and physical structure of small particles, 130 nm in diameter, isolated from the calyx of the ichneumon, Nemeritis canescens. The particles are vesicular, con­sisting of a densely-staining core surrounded by an outer membrane. The core of the particles is made up of protein and carbohydrate in the ratio 100 : 17; no nucleic acid was detected. The basic chemical subunit of the core of the particles appears to be a glycoprotein of molecular mass ca . 45000. The basic structural subunit of the core, however, is a short, hollow cylinder, about 10 nm across. It seems likely that several chemical subunits make up one structural subunit, and that many structural subunits, surrounded by the membrane, make up a single particle.

scholarly journals Coloring Single Nanoparticle Trajectory in Live Cell with its Own History: a Presuppositionless Preprocessing Approach

2019 ◽  
Author(s):  
Hansen Zhao ◽  
Zhenrong Huang ◽  
Feng Ge ◽  
Xiangjun Shi ◽  
Bin Xiong ◽  
...  
Keyword(s):  
Single Particle ◽  
Complex Dynamics ◽  
Live Cell ◽  
State Transitions ◽  
Human Beings ◽  
Global Pattern ◽  
Model Free ◽  
Mechanical Models ◽  
Data Points ◽  
Underlying Mechanisms

AbstractAnalyzing single particle trajectories is a prominent issue in understanding complex dynamics such as nanoparticle-cell interactions. Existing methods treat data points as isolated “atoms” and use predefined mechanical models to “frame” their complicated relationship. Herein, we propose a “historical evolution” based model-free strategy. It allows spatiotemporal heterogeneity embedded in a trajectory to self-emerge as consecutive colored segments before any model assumption, provide both an overall picture and local state transitions on the particle movement with minimum information loss, and inspire further model-based investigation. We demonstrate with simulations and experiments that the underlying mechanisms of various time-series and motion states of single nanoparticles on live cell membranes could all be revealed successfully. Since complexity studies at different levels of molecules, particles, cells, human beings, vehicles, and even stars could all be reduced to analyzing spatiotemporal trajectories of “single particles”, this presuppositionless approach will help fundamental researches on many important systems.Impact StatementA preprocessing strategy for single particle trajectory analysis is established by providing an intuitive global pattern from “historical experiences” of the particle without predefining any mechanical models.

A direct numerical investigation of two-way interactions in a particle-laden turbulent channel flow

2019 ◽  
Vol 875 ◽  
pp. 1096-1144 ◽  
Author(s):  
Cheng Peng ◽  
Orlando M. Ayala ◽  
Lian-Ping Wang
Keyword(s):  
Channel Flow ◽  
Finite Size ◽  
Turbulent Channel Flow ◽  
Spherical Particles ◽  
Homogeneous Distribution ◽  
Particle Sizes ◽  
Small Particles ◽  
Particle Rotation ◽  
Turbulence Modulation ◽  
Budget Analysis

Understanding the two-way interactions between finite-size solid particles and a wall-bounded turbulent flow is crucial in a variety of natural and engineering applications. Previous experimental measurements and particle-resolved direct numerical simulations revealed some interesting phenomena related to particle distribution and turbulence modulation, but their in-depth analyses are largely missing. In this study, turbulent channel flows laden with neutrally buoyant finite-size spherical particles are simulated using the lattice Boltzmann method. Two particle sizes are considered, with diameters equal to 14.45 and 28.9 wall units. To understand the roles played by the particle rotation, two additional simulations with the same particle sizes but no particle rotation are also presented for comparison. Particles of both sizes are found to form clusters. Under the Stokes lubrication corrections, small particles are found to have a stronger preference to form clusters, and their clusters orientate more in the streamwise direction. As a result, small particles reduce the mean flow velocity less than large particles. Particles are also found to result in a more homogeneous distribution of turbulent kinetic energy (TKE) in the wall-normal direction, as well as a more isotropic distribution of TKE among different spatial directions. To understand these turbulence modulation phenomena, we analyse in detail the total and component-wise volume-averaged budget equations of TKE with the simulation data. This budget analysis reveals several mechanisms through which the particles modulate local and global TKE in the particle-laden turbulent channel flow.

Sign in / Sign up

Export Citation Format

Share Document