Biomedical subjects

P J Abatti

Publications and source records attributed to P J Abatti.

4 recordsLinked to original sources

PubMed1997

Determination of the red blood cell ability to traverse cylindrical pores.

An expression relating the red blood cell (RBC) volume and membrane surface area to the pore minimum radius /maximum length which the cell is able to traverse is derived. The application of this analytical model to design/specification of filters for RBC deformability evaluation is presented. The passage of the RBC's through relatively long (10 microns or more) submicron radii pores, which the developed model demonstrates, is also discussed.

Equipment Design↗

PubMed1992

Development of a new geometrical form of micropipette: electrical characteristics and an application as a potassium ion selective electrode.

Using a mix of thermal and anodic bonding together with microlithographic techniques, the safe transference of a Si3N4 film with a pore (diameter down to 1 micron) to a glass tube tip (external diameter 800 microns) was accomplished, yielding a new geometrical form of micropipette. Compared with conventional glass micropipettes the device has shown lower resistance, more stable capacitance (independent of the tip immersion depth), tip potential closer to that of a salt bridge, and a simplified filling process. Using this device as a potassium ion selective electrode (ISE), a faster response time ISE was achieved. These features indicate that the new device can advantageously substitute the conventional glass micropipettes when cell impalement is not required.

Electric Conductivity↗

PubMed1991

Measurement of human red blood cell deformability using a single micropore on a thin Si3N4 film.

The filtration method for the evaluation of the RBC deformability has been further refined to simulate the deformations encountered in the recticuloendothelial system (in particular the spleen), a recognized site of aged and sickled cells removal. The core of the developed measuring system is a very thin (0.4 micron thick) filter that consists of single micropore (diameters down to 1 micron) on a Si3N4 film which has been constructed using silicon microfabrication techniques. Individual RBC's deformability is quantified measuring the cell pore passage time. From one blood sample 200 passage times are analyzed by a computer, displaying mean and median values as deformability indexes, and class and cumulative histograms for studying the passage times distribution. In this paper the effectiveness of the developed system as a routine clinical evaluation tool is demonstrated by studying several factors that are known to affect the RBC deformability, such as temperature, addition of diamide and glutaraldehyde, and blood storage conditions. In addition, it is experimentally demonstrated that the human RBC can traverse a pore with a diameter as small as 1 micron when the pore length is very short, thus broadening the experimental conditions under which the RBC deformability (fluidity) can be studied.

Adult↗

PubMedDate not supplied

[Incubator noise evaluation].

Measurements of noise produced by incubators and their associated live support equipment (oxygen central network)has been performed. In 33.3% of the incubators the noise level was above the standard specification (60 dB(A)) according to International Standards. Without live support equipment, the mean noise level was 58.9 dB(A). Using live support equipment with oxygen flow of 3,5 and 81/min, the mean noise level has increased to 60.5 dB(A) (P=0.53), 60.9 dB(A) (P=0.39) and 67.2dB(A) (P=0.017) respectively, showing a remarkable influence of the central gas distribution on the incubator internal noise. In 82.5% of the incubators using a plastic box over the infant's head an injecting moist oxygen/compressed air the noise level was above the standard specification; when oxygen proportion was increased the internal incubator noise level increased as well showing a statistically significant relationship between them. Measurements of impulse noise produced by incubators lateral access door handling has shown a 107.0 dB (F).

English Abstract↗