scholarly journals Characterization of Simple and Double Yeast Cells Using Dielectrophoretic Force Measurement

Sensors ◽  
2019 ◽  
Vol 19 (17) ◽  
pp. 3813 ◽  
Author(s):  
Fernando-Juan García-Diego ◽  
Mario Rubio-Chavarría ◽  
Pedro Beltrán ◽  
Francisco J. Espinós
Keyword(s):  
Electric Fields ◽  
Force Measurement ◽  
Point Of View ◽  
Yeast Cells ◽  
Instrumental Method ◽  
Particle Characterization ◽  
Dielectrophoretic Force ◽  
Cell Velocity ◽  
First Time

Dielectrophoretic force is an electric force experienced by particles subjected to non-uniform electric fields. In recent years, plenty of dielectrophoretic force (DEP) applications have been developed. Most of these works have been centered on particle positioning and manipulation. DEP particle characterization has been left in the background. Likewise, these characterizations have studied the electric properties of particles from a qualitative point of view. This article focuses on the quantitative measurement of cells’ dielectric force, specifically yeast cells. The measures are obtained as the results of a theoretical model and an instrumental method, both of which are developed and described in the present article, based on a dielectrophoretic chamber made of two V-shaped placed electrodes. In this study, 845 cells were measured. For each one, six speeds were taken at different points in its trajectory. Furthermore, the chamber design is repeatable, and this was the first time that measurements of dielectrophoretic force and cell velocity for double yeast cells were accomplished. To validate the results obtained in the present research, the results have been compared with the dielectric properties of yeast cells collected in the pre-existing literature.

Indentation response in porcine brain under electric fields

Soft Matter ◽  
2019 ◽  
Vol 15 (4) ◽  
pp. 623-632 ◽  
Author(s):  
Long Qian ◽  
Yifan Sun ◽  
Qian Tong ◽  
Jiyu Tian ◽  
Zhuang Ren ◽  
...  
Keyword(s):  
Mechanical Behavior ◽  
Brain Tissue ◽  
Electric Fields ◽  
Porcine Brain ◽  
First Time ◽  
Indentation Response

Characterization of the mechanical behavior of brain tissue under varying electric fieldsviaindentation for the first time.

scholarly journals Optical Characterization of Homogeneous and Heterogeneous Intralipid-Based Samples

2020 ◽  
Vol 10 (18) ◽  
pp. 6234
Author(s):  
Ines Delfino ◽  
Maria Lepore ◽  
Rosario Esposito
Keyword(s):  
Optical Properties ◽  
Light Scattering ◽  
Scattered Light ◽  
Industrial Applications ◽  
Point Of View ◽  
Turbid Media ◽  
Time Resolved ◽  
Propagation Of Light ◽  
First Time

Different scattering processes take place when photons propagate inside turbid media. Many powerful experimental techniques exploiting these processes have been developed and applied over the years in a large variety of situations from fundamental and applied research to industrial applications. In the present paper, we intend to take advantage of Static Light Scattering (SLS), Dynamic Light Scattering (DLS), and Time-Resolved Transmittance (TRT) for investigating all the different scattering regimes by using scattering suspensions in a very large range of scatterer concentrations. The suspensions were prepared using Intralipid 20%, a material largely employed in studies of the optical properties of turbid media, with concentrations from 10−5% to 50%. By the analysis of the angular and temporal dependence of the scattered light, a more reliable description of the scattering process occurring in these samples can be obtained. TRT measurements allowed us to obtain information on the reduced scattering coefficient, an important parameter largely used in the description of the optical properties of turbid media. TRT was also employed for the detection of inclusions embedded in Intralipid suspensions, by using a properly designed data analysis. The present study allowed us to better elucidate the dependence of scattering properties of Intralipid suspensions in a very large concentration range and the occurrence of the different scattering processes involved in the propagation of light in turbid media for the first time to our knowledge. In so doing, the complementary contribution of SLS, DLS, and TRT in the characterization of turbid media from an optical and structural point of view is strongly evidenced.

scholarly journals Isolation and Characterization of Cryptococcus neoformans Spores Reveal a Critical Role for Capsule Biosynthesis Genes in Spore Biogenesis

2009 ◽  
Vol 8 (4) ◽  
pp. 595-605 ◽  
Author(s):  
Michael R. Botts ◽  
Steven S. Giles ◽  
Marcellene A. Gates ◽  
Thomas R. Kozel ◽  
Christina M. Hull
Keyword(s):  
Cryptococcus Neoformans ◽  
Fungal Pathogens ◽  
Critical Role ◽  
Spore Formation ◽  
Yeast Cells ◽  
Isolation And Characterization ◽  
Specific Configuration ◽  
First Time

ABSTRACT Spores are essential particles for the survival of many organisms, both prokaryotic and eukaryotic. Among the eukaryotes, fungi have developed spores with superior resistance and dispersal properties. For the human fungal pathogens, however, relatively little is known about the role that spores play in dispersal and infection. Here we present the purification and characterization of spores from the environmental fungus Cryptococcus neoformans. For the first time, we purified spores to homogeneity and assessed their morphological, stress resistance, and surface properties. We found that spores are morphologically distinct from yeast cells and are covered with a thick spore coat. Spores are also more resistant to environmental stresses than yeast cells and display a spore-specific configuration of polysaccharides on their surfaces. Surprisingly, we found that the surface of the spore reacts with antibodies to the polysaccharide glucuronoxylomannan, the most abundant component of the polysaccharide capsule required for C. neoformans virulence. We explored the role of capsule polysaccharide in spore development by assessing spore formation in a series of acapsular strains and determined that capsule biosynthesis genes are required for proper sexual development and normal spore formation. Our findings suggest that C. neoformans spores may have an adapted cell surface that facilitates persistence in harsh environments and ultimately allows them to infect mammalian hosts.

scholarly journals Characters of Sart-Kalmyk Version of Epic “Dzhangar”

2020 ◽  
Vol 1 (10) ◽  
pp. 231-242
Author(s):  
B. Kh. Borlykova ◽  
B. V. Menyaev
Keyword(s):  
Individual Differences ◽  
Point Of View ◽  
Epic Tradition ◽  
Individual Family ◽  
Field Notes ◽  
First Time ◽  
The Village ◽  
External Characteristics

Based on the well-known work of E.S. Novik (2001), for the first time, the experience of describing the internal and external characteristics of the characters of the Sart-Kalmyk version of the “Dzhangar” epic from the point of view of their individual, family and class conditions is presented in this article. The material for the analysis was the unpublished texts of the epic “Dzhangar”, recorded in 1929 by A. V. Burdukov and in 1972 by A. Sh. Kichikov in the village of Chelpek in the Ak-Suu district of the Przhevalsk region of Kyrgyzstan. For comparison, the published songs of the Kalmyk and Xinjiang Oirat versions of the epic “Dzhangar”, Kalmyk heroic tales, as well as the authors’ personal field notes were used. As a result of the analysis of the Sart-Kalmyk version of the epic “Dzhangar”, the authors came to the conclusion that for the in-plot functioning of the characters, it is important not only what role they play, but also what internal and external characteristics they are endowed with, since they correspond to those actions in which real characters take part. The characterization of the characters, playing up in the plot of the epic, sets the form of collisions. It was revealed that the victory of the heroes of the epic “Dzhangar” is associated with the following characteristics of the character: “strong / weak” and “brave / cowardly”, “whole / dismembered”, etc. Comparative consideration of the characters of the epic “Dzhangar” showed that the epic heroes have both similarities and local individual differences. However, the main functions that they perform in one version or another are close, going back to the ancient all-Mongolian epic tradition.

scholarly journals Puccinellia maritima, Spartina maritime, and Spartina patens Halophytic Grasses: Characterization of Polyphenolic and Chlorophyll Profiles and Evaluation of Their Biological Activities

Molecules ◽  
2019 ◽  
Vol 24 (20) ◽  
pp. 3796 ◽  
Author(s):  
Maria V. Faustino ◽  
Maria A. F. Faustino ◽  
Helena Silva ◽  
Ângela Cunha ◽  
Artur M. S. Silva ◽  
...  
Keyword(s):  
Biological Activities ◽  
Photophysical Properties ◽  
Spartina Patens ◽  
Point Of View ◽  
Antibacterial And Antifungal Activities ◽  
Antibacterial And Antifungal ◽  
Ferulic Acids ◽  
First Time ◽  
Halophytic Grasses

Halophytic grasses have been recently targeted as possible sources of nutraceutical and medicinal compounds. Nonetheless, few studies have been conducted on the phytochemistry and biological activities of metabolites produced by these plants. Among these, Spartina maritima (Curtis) Fernald, Spartina patens (Aiton.) Muhl., and Puccinellia maritima (Hudson) Parl. are three halophytic grasses whose chemical composition and bioactivities are unknown. The present work broadens the knowledge on the polyphenolic and chlorophyll composition of these species identifying for the first time hydroxycinnamic acids and their derivatives, flavones, flavonols, lignans, as well as chlorophylls and xantophylls. The extracts were particularly rich in caffeic and ferulic acids as well as in trihydroxymethoxyflavone, apigenin and tricin derivatives. Interestingly, several of the identified compounds are relevant from a medicinal and nutraceutical point of view putting in evidence the potential of these species. Thus, the antioxidant, anti-acetylcholinesterase, antibacterial, and antifungal activities of the polyphenolic extracts were assessed as well as the photophysical properties of the chlorophyll-rich extracts. The results, herein presented for the first time, reinforce the nutritional and the medicinal potential of these halophytic grasses.

scholarly journals Thermal Shock Response of Yeast Cells Characterised by Dielectrophoresis Force Measurement

Sensors ◽  
2019 ◽  
Vol 19 (23) ◽  
pp. 5304
Author(s):  
García-Diego Fernando-Juan ◽  
Mario Rubio-Chavarría ◽  
Pedro Beltrán ◽  
Francisco J. Espinós
Keyword(s):  
Cell Membrane ◽  
Yeast Cell ◽  
Electric Fields ◽  
Force Measurement ◽  
Cell Structure ◽  
Biological Properties ◽  
Yeast Cells ◽  
Uniform Electric Field ◽  
Membrane Conductivity ◽  
Conductivity Cell

Dielectrophoresis is an electric force experienced by particles subjected to non-uniform electric fields. Recently, several technologies have been developed focused on the use of dielectrophoretic force (DEP) to manipulate and detect cells. On the other hand, there is no such great development in the field of DEP-based cell discrimination methods. Despite the demand for methods to differentiate biological cell states, most DEP developed methods have been focused on differentiation through geometric parameters. The novelty of the present work relies upon the point that a DEP force cell measurement is used as a discrimination method, capable of detecting heat killed yeast cells from the alive ones. Thermal treatment is used as an example of different biological state of cells. It comes from the fact that biological properties have their reflection in the electric properties of the particle, in this case a yeast cell. To demonstrate such capability of the method, 279 heat-killed cells were measured and compared with alive cells data from the literature. For each cell, six speeds were taken at different points in its trajectory inside a variable non-uniform electric field. The electric parameters in cell wall conductivity, cell membrane conductivity, cell membrane permittivity of the yeast cell from bibliography explains the DEP experimental force measured. Finally, alive and heat-treated cells were distinguished based on that measure. Our results can be explained through the well-known damage of cell structure characteristics of heat-killed cells.

scholarly journals A Langmuir Probe – fluxgate magnetometer combination for Comet Interceptor

2021 ◽  
Author(s):  
Johan De Keyser ◽  
Sylvain Ranvier ◽  
Jeroen Maes ◽  
Jordan Pawlak ◽  
Eddy Neefs ◽  
...  
Keyword(s):  
Electric Fields ◽  
Langmuir Probe ◽  
Fluxgate Magnetometer ◽  
Magnetic Field Direction ◽  
Strong Activity ◽  
Plasma Environment ◽  
Spacecraft Potential ◽  
First Time

<p>ESA’s Comet Interceptor mission is a low budget, fast track mission to a dynamically new comet (DNC). As a DNC enters the inner solar system for the first time, it is expected to feature strong activity and to display a fluid-scale plasma environment, rather than the kinetic-scale environment encountered at weakly active objects such as 67P.  In situ characterization of this plasma environment is therefore one of the main mission objectives and is the object of the Dust-Fields-Plasma instrument, a suite of sensors for the measurement of the dust, the plasma populations, and the magnetic and electric fields and waves, with the field sensors being mounted on booms, all within strict mass, power, and budget constraints. In this context a sensor has been developed that harbors a fluxgate magnetometer at the center of a hollow spherical Langmuir probe. Precautions have been taken to minimize the possible interference between both, while at the same time being very lightweight. An engineering model has been built, tested and characterized in detail. Together with a companion Langmuir probe and an additional magnetometer in gradiometer configuration, the probe-magnetometer combination (COMPLIMENT + FGM) provides data regarding magnetic and electric fields and waves, total ion and electron densities and electron temperature, as well as the ambient nanodust population. It also offers reference data for the other sensors, such as magnetic field direction, spacecraft potential and total plasma density at high cadence, and integrated EUV flux.</p>

Particle characterization of CVD tungsten metallization for 64 MBIT DRAM

1991 ◽  
Vol 49 ◽  
pp. 896-897
Author(s):  
Marylyn Bennett-Lilley ◽  
Thomas T.H. Fu ◽  
David D. Yin ◽  
R. Allen Bowling
Keyword(s):  
Chemical Vapor ◽  
Device Performance ◽  
Particle Characterization ◽  
Particle Generation ◽  
Tungsten Hexafluoride ◽  
Homogeneous Particle ◽  
Multiple Levels ◽  
Circuit Density ◽  
Sources Of Contamination

Chemical Vapor Deposition (CVD) tungsten metallization is used to increase VLSI device performance due to its low resistivity, and improved reliability over other metallization schemes. Because of its conformal nature as a blanket film, CVD-W has been adapted to multiple levels of metal which increases circuit density. It has been used to fabricate 16 MBIT DRAM technology in a manufacturing environment, and is the metallization for 64 MBIT DRAM technology currently under development. In this work, we investigate some sources of contamination. One possible source of contamination is impurities in the feed tungsten hexafluoride (WF6) gas. Another is particle generation from the various reactor components. Another generation source is homogeneous particle generation of particles from the WF6 gas itself. The purpose of this work is to investigate and analyze CVD-W process-generated particles, and establish a particle characterization methodology.

TBE in Sweden

2020 ◽  
Keyword(s):  
Genetic Characterization ◽  
Immunoglobulin M ◽  
Enzyme Linked Immunosorbent Assay ◽  
Second Phase ◽  
Serum Samples ◽  
Tick Borne Encephalitis ◽  
Specific Immunoglobulin ◽  
Tick Borne Encephalitis Virus ◽  
First Time

Tick-borne encephalitis virus (TBEV) was isolated for the first time in Sweden in 1958 (from ticks and from 1 tick-borne encephalitis [TBE] patient).1 In 2003, Haglund and colleagues reported the isolation and antigenic and genetic characterization of 14 TBEV strains from Swedish patients (samples collected 1991–1994).2 The first serum sample, from which TBEV was isolated, was obtained 2–10 days after onset of disease and found to be negative for anti-TBEV immunoglobulin M (IgM) by enzyme-linked immunosorbent assay (ELISA), whereas TBEV-specific IgM (and TBEV-specific immunoglobulin G/cerebrospinal fluid [IgG/CSF] activity) was demonstrated in later serum samples taken during the second phase of the disease.

Thanato-Laboratorien. Theorien von Tod und Sterben und Elias Canettis Buch gegen den Tod

2020 ◽  
Vol 4 (1) ◽  
pp. 67-86
Author(s):  
Elisabeth Heyne
Keyword(s):  
Human Life ◽  
Death And Dying ◽  
Point Of View ◽  
Visual Images ◽  
Elias Canetti ◽  
History Of ◽  
Series Of Experiments ◽  
First Time ◽  
Textual Form ◽  
Or History

AbstractAlthough visual culture of the 21th century increasingly focuses on representation of death and dying, contemporary discourses still lack a language of death adequate to the event shown by pictures and visual images from an outside point of view. Following this observation, this article suggests a re-reading of 20th century author Elias Canetti. His lifelong notes have been edited and published posthumously for the first time in 2014. Thanks to this edition Canetti's short texts and aphorisms can be focused as a textual laboratory in which he tries to model a language of death on experimental practices of natural sciences. The miniature series of experiments address the problem of death, not representable in discourses of cultural studies, system theory or history of knowledge, and in doing so, Canetti creates liminal texts at the margins of western concepts of (human) life, science and established textual form.

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