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At least 1,531 records · Page 85Linked to original sources
PubMed1984

A signal processor for a multiple-electrode hearing prosthesis.

A 22-electrode implantable hearing prosthesis uses a wearable speech processor which estimates three speech signal parameters. These are voice pitch, second formant frequency and flattened spectrum amplitude. The signal is monitored continuously for periodicity in the range 80-400 Hz and, if this is present, stimulation occurs at the same rate. Otherwise, as in the case of unvoiced sounds, it occurs at the random rate of fluctuation of the signal envelope. The second formant is obtained by filtering to extract the dominant peak in the midband region and by continuous measurement of the zero crossing rate. The amplitude measured is that of the whole speech spectrum, pre-emphasized by differentiation. The values that are presented to the patient are the parameter estimates immediately prior to the stimulation pulse. Second formant frequency is coded by selection of an appropriate electrode in the cochlea and amplitude by a suitably controlled current. Automatic gain control is used to keep the dynamic range of the amplitude estimate within the 30 dB range of the circuitry.

Cochlear Implants↗
PubMedDate not supplied

[Disorientation and psychomotor sluggishness as parameters of estimation of brain damage assessment].

In a group of 110 patients with cerebral lesions the relationships were analysed between 7 features (patient's age, educational level, disorientation, psychomotor sluggishness, clinical diagnosis, EEG pattern, character and site of lesion) using the method of cluster analysis (Wrocław taxonomy). A correlation was noted between disorientation, diagnosis, character and site of lesions and age. No significant correlation was demonstrable between disorientation and psychomotor sluggishness. EEG changes and educational level were not related to any of the above features.

Adolescent↗
PubMedDate not supplied

[Rapid turbidimetric micromethod for the simultaneous estimation of parameters of coagulation and fibrinolysis in blood plasma].

A method has been developed to determine six parameters of coagulation and fibrinolysis by means of turbidimetry; 0.1 ml of dissolved plasma after its activation with thrombin and streptokinase is used. Testing conditions which permit performing express diagnostics of haemostasis disturbances and controlling their correction have been optimized.

Blood Coagulation↗
PubMed1997

Training a large number of laboratory mice using running wheels and analyzing running behavior by use of a computer-assisted system.

A great many studies in the literature describe the variety of ways to provide physical training to small laboratory animals. Forced running on a treadmill or swimming training require considerable effort from the researcher, but permit the investigator to control the amount of exercise. Another option is to provide animals with access to running wheels, which they can voluntarily operate. Wheels can be used to investigate the running behavior of the animals. Wheel motion usually has been detected with magnets and microswitches and has been recorded using strip chart recorders or electromechanical counters. Computers also have been used in recording, but the measured parameters usually have been able to define only the total distance run in a fixed period. We designed a system, using running wheels, that can be used for long periods, up to years, for training a large number of laboratory mice simultaneously (maximal n = 96). The running parameters estimated by our system include running distance, speed, and time. Cumulative estimates of the running parameters can be produced for any period, as short as 1 sec. It is also easy to perform statistical analyses on the data. Using the system, we investigated the running behavior of 21 young C57BL/6 male mice. After the fast growth period, until 8 weeks of age, the mice ran 4 to 5 km/day at an average speed of 23 m/min, and spent 3 h running each day. This took place during the hours of darkness.

Animals↗
PubMed1997

Application of a first-pass effect model to characterize the pharmacokinetic disposition of venlafaxine after oral administration to human subjects.

Venlafaxine (VEN), a drug used in the treatment of depression, undergoes significant first-pass metabolism after oral dosing to O-desmethylvenlafaxine (ODV), a metabolite with comparable therapeutic activity to that of parent drug. The pharmacokinetic disposition of VEN was characterized using a "first-pass" model that incorporates a presystemic compartment (liver) to account for the first-pass metabolism of VEN to ODV. A series of differential equations were simultaneously fitted to plasma concentrations of parent and metabolite. A good fit of the model to observed data was demonstrated, generating estimates for the following parameters: ka (1.31 +/- 0.009 hr-1), VVEN (252 +/- 87.6 liters), CLint (65.8 +/- 39.7 liters/hr), RL (liver:plasma partition coefficient, 29.6 +/- 18. 3), VODV (181 +/- 84.1 liters), and CLODV (23.5 +/- 12.5 liters/hr). Parameter estimates correlated closely with those obtained through noncompartmental methods. These results indicate that the time-course disposition of a compound undergoing first-pass hepatic metabolism after oral dosing can be successfully modeled.

Administration, Oral↗
PubMed1984

Maximum likelihood estimation of genetic parameters of HLA-linked diseases using data from families of various sizes.

This paper is concerned with estimating parameters associated with HLA-linked diseases. We consider a single disease locus closely linked to HLA, allowing a disease and a normal allele. The parameters to be estimated are the penetrances of the genotypes at the disease locus, the population frequency of the disease allele, and the distance of the disease locus from HLA. The presently used method of estimation uses HLA-sharing information from affected sib-pairs. The method proposed here generalizes the previous approach, using data from all sibs (affected or unaffected) in a family of any size. It allows immediate generalizations to the use of information on parental affectedness status and population prevalence.

Alleles↗