Epidemiologic Concepts and Methods

Evans, Alfred S.

doi:10.1007/978-1-4613-0705-1_1

Cited by 23 publications

(27 citation statements)

References 117 publications

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“…In the past few decades, many etiological agents of respiratory tract illnesses (RTI) have been identified 9,10 . However, a proportion of these illnesses still cannot be attributed to known pathogens.…”

Section: Articlesmentioning

confidence: 99%

A newly discovered human pneumovirus isolated from young children with respiratory tract disease

Hoogen

Jong

Groen

et al. 2001

Nat Med

1,813

1,796

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From 28 young children in the Netherlands, we isolated a paramyxovirus that was identified as a tentative new member of the Metapneumovirus genus based on virological data, sequence homology and gene constellation. Previously, avian pneumovirus was the sole member of this recently assigned genus, hence the provisional name for the newly discovered virus: human metapneumovirus. The clinical symptoms of the children from whom the virus was isolated were similar to those caused by human respiratory syncytial virus infection, ranging from upper respiratory tract disease to severe bronchiolitis and pneumonia. Serological studies showed that by the age of five years, virtually all children in the Netherlands have been exposed to human metapneumovirus and that the virus has been circulating in humans for at least 50 years.

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Section: Articlesmentioning

confidence: 99%

A newly discovered human pneumovirus isolated from young children with respiratory tract disease

Hoogen

Jong

Groen

et al. 2001

Nat Med

1,813

1,796

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“…The shell model of the cell was successfully applied to analyze mechanisms of sound attenuation in blood and in erythrocyte suspensions [22]. A similar model was used for description of shape oscillations of drops in the presence of surfactants [23,24] and for modeling the recovery of nonadherent cells after micropipette extension [25]. Within the shell model, a bacterium is assumed to have a spherical shape of radius a (Fig.…”

Section: Modelmentioning

confidence: 99%

Deformation of biological cells in the acoustic field of an oscillating bubble

Zinin

Allen

2009

Phys. Rev. E

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In this work we develop a theoretical framework of the interaction of microbubbles with bacteria in the ultrasound field using a shell model of the bacteria, following an approach developed previously [P. V. Zinin et al., Phys. Rev. E 72, 61907 (2005)]. Within the shell model, the motion of the cell in an ultrasonic field is determined by the motion of three components: the internal viscous fluid, a thin elastic shell, and the surrounding viscous fluid. Several conclusions can be drawn from the modeling of sound interaction with a biological cell: (a) the characteristics of a cell's oscillations in an ultrasonic field are determined both by the elastic properties of the shell the viscosities of all components of the system, (b) for dipole quadrupole oscillations the cell's shell deforms due to a change in the shell area this oscillation depends on the surface area modulus K A , (c) the relative change in the area has a maximum at frequency , where a is the cell's radius and ρ is its density. It was predicted that deformation of the cell wall at the frequency f K is high enough to rupture small bacteria such as E. coli in which the quality factor of natural vibrations is less than 1 (Q < 1). For bacteria with high value quality factors (Q > 1), the area deformation has a strong peak near a resonance frequency f K ; however, the value of the deformation near the resonance frequency is not high enough to produce sufficient mechanical effect. The theoretical framework developed in this work can be extended for describing the deformation of a biological cell under any arbitrary, external periodic force including radiation forces unduced by acoustical (acoustical levitation) or optical waves (optical tweezers).

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“…Indeed, there is a long history of the study of cells at the micrometer scale for assessing mechanical properties (20) and cell shape (21) and for applying these ideas for understanding microcirculatory diseases (22,23). In fact, the main approach for characterizing the influence of possible diseases on a suspension of cells is the filtration technique (23)(24)(25).…”

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confidence: 99%

High-speed microfluidic differential manometer for cellular-scale hydrodynamics

Abkarian

Faivre

Stone

2006

Proc. Natl. Acad. Sci. U.S.A.

166

133

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We propose a broadly applicable high-speed microfluidic approach for measuring dynamical pressure-drop variations along a micrometer-sized channel and illustrate the potential of the technique by presenting measurements of the additional pressure drop produced at the scale of individual flowing cells. The influence of drug-modified mechanical properties of the cell membrane is shown. Finally, single hemolysis events during flow are recorded simultaneously with the critical pressure drop for the rupture of the membrane. This scale-independent measurement approach can be applied to any dynamical process or event that changes the hydrodynamic resistance of micro-or nanochannels.pressure measurement ͉ microcirculation ͉ hemolysis ͉ red blood cell ͉ membrane properties F luid motions at the micrometer scale are at the heart of many recent developments in microfabrication (1), separation processes (2), cellular-scale identifications (3), DNA sequencing (4), protein crystallization (5) and many basic transport pathways in plants (6), in the microcirculation (7), and specific to industrial processes. The main characteristics of these advances lie in the manipulation and understanding of the dynamics of ''soft'' objects such as polymers (8) (e.g., DNA), drops (9, 10), microemulsions (11), microfoams (12), cells (13), vesicles and microcapsules (14). In fact, the interaction of the flow with these deformable entities is a tool to further investigate the details of their mechanical properties and their structural features (e.g., the entropic elasticity of a polymer, the viscoelastic properties of a capsule, or the rheology of the liquid film between microbubbles in a foam). For the case of strong confinement offered by microchannels, the flow and shape of any close-fitting soft object is controlled by a competition among the properties of the objects, the fluid pressure, and the viscous stresses acting on the boundaries that resist the motion. The hydrodynamic resistance resulting from this fluid-structure interaction is reflected in a dynamical variation of the pressure drop along the channel during the flow and hence represents a crucial parameter to be measured.Nevertheless, rapid variations of pressure are very difficult to measure at the micrometer scale and below. Indeed, the difficulties do not originate from the lack of precision sensors commercially available or those described in the research literature (15). The problem is a subtle mix of pragmatism and technological limits. In addition to issues of dead volumes in standard pressure-measurement techniques (16-18) and those associated with interfacing microelectromechanical system devices to standard pressure gauges (19), existing techniques are simply difficult to implement [lasers, quadrant diodes, deformable membranes, multistep process of production (16-18)] and are unable to measure at millisecond rates the pressure changes in micrometer-scale flows. For instance, when a single red blood cell (RBC) enters a channel of 5 ϫ 5 m, the volume variation produced b...

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Epidemiologic Concepts and Methods

Cited by 23 publications

References 117 publications

A newly discovered human pneumovirus isolated from young children with respiratory tract disease

A newly discovered human pneumovirus isolated from young children with respiratory tract disease

Deformation of biological cells in the acoustic field of an oscillating bubble

High-speed microfluidic differential manometer for cellular-scale hydrodynamics

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