scholarly journals Dielectrophoresis Manipulation: Versatile Lateral and Vertical Mechanisms

Biosensors ◽  
2019 ◽  
Vol 9 (1) ◽  
pp. 30 ◽  
Author(s):  
Muhamad Buyong ◽  
Aminuddin Kayani ◽  
Azrul Hamzah ◽  
Burhanuddin Yeop Majlis
Keyword(s):  
Surrounding Medium ◽  
Side Wall ◽  
Physical Contact ◽  
Selective Detection ◽  
Dielectric Particles ◽  
Technology Applications ◽  
Artificial Kidneys ◽  
Study Methodology ◽  
Research Drug ◽  
Efficiency Rate

Discussing the topic of the capability of dielectrophoresis (DEP) devices in terms of the selective detection and rapid manipulation of particles based on the DEP force (FDEP) via contactless methods is challenging in medical research, drug discovery and delivery. Nonetheless, the process of the selective detection and rapid manipulation of particles via contactless DEP based on dielectric particles and the surrounding medium can reduce the effects of major issues, including physical contact with the particles and medium contamination to overcome operational difficulties. In this review, DEP microelectromechanical system (MEMS) microelectrodes with a tapered profile for the selective detection and rapid manipulation of particles were studied and compared with those of conventional designs with a straight-cut profile. The main objective of this manuscript is to review the versatile mechanism of tapered DEP MEMS microelectrodes for the purpose of selective detection and rapid manipulation. Thus, this review provides a versatile filtration mechanism with the potential for a glomerular-based membrane in an artificial kidneys’ development solution for implementing engineered particles and cells by lateral attraction as well as vertical repulsion in the development of lab-on-a-chip applications. For tapered DEP MEMS microelectrodes, the scope of this study methodology involved the characterisation of DEP, modelling of the polarisation factor and the dynamic dielectric changes between the particles and medium. Comprehensive discussions are presented on the capability of tapered DEP microelectrodes to drive the selected particles and the simulation, fabrication and testing of the tapered profile. This study revealed an outstanding performance with the capability of producing two regions of high electric field intensity at the bottom and top edges of the side wall of tapered microelectrodes. Observations on particle separation mainly by the lateral attraction force of particles with positive DEP on the y-axis and vertical repulsion force of particles with negative DEP on the z-axis proved an efficient and uniform FDEP produced by tapered electrodes. In conclusion, this study confirmed the reliability and efficiency of the tapered DEP microelectrodes in the process of selective detection and rapid manipulation at a higher efficiency rate than straight-cut microelectrodes, which is significant in DEP technology applications.

A Stiction Study via C-V Plot Electrostatic Actuation/Latching

1999 ◽  
Author(s):  
Gary O’Brien ◽  
Liwei Lin ◽  
David J. Monk
Keyword(s):  
Surface Energy ◽  
Parallel Plate ◽  
Physical Contact ◽  
Spring Constant ◽  
Mechanical Parameters ◽  
Parallel Plate Capacitor ◽  
Average Force ◽  
Electrostatically Actuated ◽  
Capacitance Voltage ◽  
Study Methodology

Abstract We have demonstrated a stiction study methodology on the microscale via an electrostatically actuated polysilicon parallel plate capacitor. The actuator was used to cause physical contact between two polysilicon microstructures. C-V (capacitance-voltage) plots were used to extract mechanical parameters, including surface energy (J/m2), force of adhesion (N), and spring constant (N/m). An average surface energy of 8.9 mJ/m2 with corresponding standard deviation (σ) of 0.8 mJ/m2 was observed regarding polysilicon adhesion. The average force of adhesion was calculated to be 13.3 μN (σ = 1.2 μN) for a contact surface area of 1.256 × 10−9 m2. The calculated Z-axis spring constant was 15.9 N/m (σ = 1.6 N/m) as compared to the theoretical value of 16.8 N/m.

The Fine Structure of Rat Granulosa Cell Cultures Correlated with Progestin Secretion

1973 ◽  
Vol 31 ◽  
pp. 552-553
Author(s):  
T. M. Crisp ◽  
F.R. Denys
Keyword(s):  
Fine Structure ◽  
Granulosa Cell ◽  
Cell Cultures ◽  
Single Injection ◽  
Surrounding Medium ◽  
Petri Dish ◽  
Female Rats ◽  
Vaginal Smear ◽  
Immature Female ◽  
Serum Gonadotropin

The purpose of this paper is to present observations on the fine structure of rat granulosa cell cultures grown in the presence of an adenohypophyseal explant and to correlate the morphology of these cells with progestin secretion. Twenty-six day old immature female rats were given a single injection of 5 IU pregnant mares serum gonadotropin (PMS) in order to obtain ovaries with large vesicular follicles. At 66 hrs. post-PMS administration (estrus indicated by vaginal smear cytology), the ovaries were removed and placed in a petri dish containing medium 199 and 100 U penicillin/streptomycin (P/S)/ml. Under a 20X magnification dissecting microscope, some 5-8 vesicular follicles/ovary were punctured and the granulosa cells were expressed into the surrounding medium. The cells were transferred to centrifuge tubes and spun down at 1000 rpm for 5 mins.

Scanning Electron Microscope Study of Bacteria on Mineral Surfaces

1976 ◽  
Vol 34 ◽  
pp. 130-131
Author(s):  
V.K. Berry
Keyword(s):  
Oxidation Reaction ◽  
Electron Microscope Study ◽  
Elemental Sulfur ◽  
Thiobacillus Ferrooxidans ◽  
Physical Contact ◽  
Metal Sulfides ◽  
Low Grade ◽  
Mineral Surfaces ◽  
Mineral Surface ◽  
Scanning Electron Microscope Study

There are two strains of bacteria viz. Thiobacillus thiooxidansand Thiobacillus ferrooxidanswidely mentioned to play an important role in the leaching process of low-grade ores. Another strain used in this study is a thermophile and is designated Caldariella .These microorganisms are acidophilic chemosynthetic aerobic autotrophs and are capable of oxidizing many metal sulfides and elemental sulfur to sulfates and Fe2+ to Fe3+. The necessity of physical contact or attachment by bacteria to mineral surfaces during oxidation reaction has not been fairly established so far. Temple and Koehler reported that during oxidation of marcasite T. thiooxidanswere found concentrated on mineral surface. Schaeffer, et al. demonstrated that physical contact or attachment is essential for oxidation of sulfur.

The Solidarity of Distance1

2005 ◽  
Vol 36 (3) ◽  
pp. 103-115 ◽  
Author(s):  
Robert A. Wicklund
Keyword(s):  
Physical Contact ◽  
Emotional Distance ◽  
Starting Point ◽  
Shared Emotions ◽  
Common Goals ◽  
Full Interaction ◽  
The Individual ◽  
Social Incompetence

Abstract: Solidarity in the classic sense pertains to a cohesion among humans that entails physical contact, shared emotions, and common goals or projects. Characteristic cases are to be found among families, close friends, or co-workers. The present paper, in contrast, treats a phenomenon of the solidarity of distance, a solidarity based in fear of certain others and in incompetence to interact with them. The starting point for this analysis is the person who is motivated to interact with others who are unfamiliar or fear-provoking. Given that the fear and momentary social incompetence do not allow a full interaction to ensue, the individual will move toward solidarity with those others on a symbolic level. In this manner the motivation to approach the others is acted upon while physical and emotional distance is retained.

Selective detection of glutathione based on the recovered fluorescence of BSA‐AuNCs/Cu 2+ system

2019 ◽  
Vol 14 (9) ◽  
pp. 952-956
Author(s):  
Yining Zhu ◽  
Wang Li ◽  
Cheng Ju ◽  
Xiang Gong ◽  
Wenhao Song ◽  
...  
Keyword(s):  
Selective Detection

Teacher Professional Training and Student Academic Performance at an University from Lima, 2016 [Formación Profesional Docente y Rendimiento Académico en Estudiantes de una Universidad de Lima, 2016]

2019 ◽  
Vol 1 (2) ◽  
pp. 116
Author(s):  
Jorge Luis Torres Ugaz
Keyword(s):  
Veterinary Medicine ◽  
Academic Performance ◽  
Educational System ◽  
Professional Training ◽  
Student Academic Performance ◽  
Teacher Professional ◽  
Study Methodology ◽  
The Relationship

This work emphasizes the teaching work in the progress of the educational system. The objective was to determine the relationship between the Teacher Professional Training and the Academic Performance of the students of Veterinary Medicine and Zootechnics of an University of Lima, Perú. The study methodology was correlational, the sample was 6 teachers and 72 students. The teachers were surveyed and the students were evaluated through the minutes. A mean and direct correlation of 44.05% was obtained between the variables studied.

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