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At least 19 recordsLinked to original sources
PubMedDate not supplied

[Comparison of auscultation findings using a classic stethoscope (Litmann 2120) and electronically amplified stethoscope (Medmax2)].

Heart auscultation has one of the key roles in beside diagnosis, especially in patients with cardiovascular diseases. Sometimes, because of the human cars' low sensitivity, a problem emerges in the proper evaluation of heart sounds and murmurs of lower frequencies. Our study compared two stethoscopes, the classic acoustic stethoscope (Littmann 2120) and an electronic one with the sound amplifier and the noise filtering system (Medmax2) in 10 patients examined by 10 physicians. Significantly better detection of low frequency sounds was found in favour of electronic stethoscope (chi 2 = 17.9; p < 0.0001). It is concluded that the selective amplificator improves the stethoscope performance and has its place in everyday bedside practice, especially in departments of cardiology.

Aged↗
PubMed2001

Detection of single-base DNA mutations by enzyme-amplified electronic transduction.

Here we describe a method for the sensitive detection of a single-base mutation in DNA. We assembled a primer thiolated oligonucleotide, complementary to the target DNA as far as one base before the mutation site, on an electrode or a gold-quartz piezoelectric crystal. After hybridizing the target DNA, normal or mutant, with the sensing oligonucleotide, the resulting assembly is reacted with the biotinylated nucleotide, complementary to the mutation site, in the presence of polymerase. The labeled nucleotide is coupled only to the double-stranded assembly that includes the mutant site. Subsequent binding of avidin-alkaline phosphatase to the assembly, and the biocatalyzed precipitation of an insoluble product on the transducer, provides a means to confirm and amplify detection of the mutant. Faradaic impedance spectroscopy and microgravimetric quartz-crystal microbalance analyses were employed for electronic detection of single-base mutants. The lower limit of sensitivity for the detection of the mutant DNA is 1 x 10-14 mol/ml. We applied the method for the analysis of polymorphic blood samples that include the Tay-Sachs genetic disorder. The sensitivity of the method enables the quantitative analysis of the mutant with no PCR pre-amplification.

Alkaline Phosphatase↗
PubMed1993

Longitudinal changes in hearing ability among Swedish conscripts.

An analysis of a military database of about 36,000 tone audiograms from male Swedish conscripts aged 18 to 19 and recorded from 1969 to 1977 demonstrates a successively decreasing prevalence of hearing loss during this period. This might reflect improved therapy during the 1950s and 1960s of ear disorders causing hearing loss in small children. If observations in other studies on a reverse trend during the 1980s are confirmed, they indicate, together with the present study, that around 1980 young people began to be harmfully exposed to an environmental factor causing hearing loss. If this is the case, the causative factor would probably be non-occupational exposure to electronically amplified sounds from loudspeakers and headphones.

Acoustic Stimulation↗
PubMed1989

Modified Box-Cox transform for modulating the dynamic range of flow cytometry data.

We describe an algorithm, Vout = Integer ([2(12)-1/2(12 lambda)-1] V lambda in-1) + 1; lambda greater than 0 based upon Box-Cox transformations as an alternative to nonlinear electronic amplifiers to expand or compress high- or low-amplitude flow cytometer-derived signals. If the indexing parameter lambda less than 1, input channels in the high-amplitude input range are compressed in the output range as occurs when an electronic logarithmic amplifier is used. However, if lambda greater than 1, input channels in the low-amplitude input range are compressed in the output range as occurs when an electronic power amplifier is used. Our modified Box-Cox transform can be implemented either during data collection or off-line for the transformation of previously collected raw data. The transform is the equivalent of an infinite class of nonlinear amplifiers. As the transform is implemented in software, it does not suffer from many of the disadvantages of nonlinear electronic amplifiers.

Algorithms↗
PubMed1985

The electronic pantograph: amplifier couples microscope stage to X-Y plotter.

A system is described that allows the X-Y movement of a microscope stage to be coupled to the movement of the pen of a X-Y plotter. Linear potentiometers are displaced by any X- or Y-axis movement of the microscope's stage and are connected to a DC amplifier which provides a varying DC voltage to the inputs of a X-Y plotter. The pen of the X-Y plotter becomes yoked to the movement of the stage and it is possible to draw or count the image that is being viewed at magnifications which are independent of those used for observation. The coupling DC amplifier provides a DC offset voltage at all gain settings of the pantograph which is sufficient to reposition the pen of the X-Y plotter in the center of the plotter's platen, regardless of the location of the specimen on the microscope slide. The electronic pantograph overcomes the limitations of a camera lucida, and is well suited for analyzing connectional neuroanatomical material with bright- and darkfield, polarized light or florescent illumination at a reasonable price and without the complexity and hardware requirements of a computerized system.

Animals↗