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Biomedical subjects

I Baruch

Publications and source records attributed to I Baruch.

8 recordsLinked to original sources
PubMed2002

Neural networks applied to the prediction of fed-batch fermentation kinetics of Bacillus thuringiensis.

This paper proposes using a new recurrent neural network model (RNNM) to predict and control fed batch fermentations of Bacillus thuringiensis. The control variables are the limiting substrate and the feeding conditions. The multi-input multi-output RNNM proposed has twelve inputs, seven outputs, nineteen neurons in the hidden layer, and global and local feedbacks. The weight update learning algorithm designed is a version of the well known backpropagation through time algorithm directed to the RNNM learning. The error approximation for the last epoch of learning is 2% and the total learning time is 51 epochs, where the size of an epoch is 162 iterations. The RNNM generalization was carried out reproducing a B. thuringiensis fermentation not included in the learning process. It attains an error approximation of 1.8%.

Journal Article↗
PubMed1998

Hypocapnia does not alter hepatic blood flow or oxygen consumption in patients with head injury.

OBJECTIVE: To evaluate the effects of hypocapnia on the systemic and hepatic circulations and oxygenation values in patients with head injury. DESIGN: Open-label, prospective study. SETTING: University hospital, department of anesthesiology and intensive care unit. PATIENTS: Eleven mechanically ventilated patients with isolated head trauma and stable hemodynamic status. INTERVENTIONS: At the beginning of the study, each patient presented with normocapnic ventilation. Mechanical hyperventilation was then adjusted to obtain stable hypocapnia over an interval of 24 hrs. Cardiac output and other systemic hemodynamic parameters were measured, using a pulmonary artery catheter. Hepatic parameters were measured via a catheter inserted into the hepatic vein. Total hepatic blood flow was determined by the Fick principle using a continuous infusion of indocyanine green. Arterial and hepatic venous blood gases were sampled to determine systemic and hepatic-splanchnic oxygenation. Measurements were done at the end of the four phases: a) 30 mins of normocapnia (N); b) 30 mins of hypocapnia (H0); c) 3 hrs of hypocapnia (H3); and d) 24 hrs of hypocapnia (H24). Intracranial pressure and cerebral perfusion pressure were hourly monitored throughout the study. MEASUREMENTS AND MAIN RESULTS: There were no significant changes in systemic hemodynamic parameters. The hepatic blood flow index did not differ from normocapnia (N 1.8 +/- 0.4 L/min/m2) to hypocapnia (H0 1.6 +/- 0.3 L/min/m2; H3 1.7 +/- 0.4 L/min/m2; H24 1.7 +/- 0.4 L/min/m2). The ratio of hepatic blood flow index to cardiac index remained stable throughout the study. Hypocapnia did not affect hepatic-splanchnic oxygen delivery and consumption. CONCLUSIONS: Hypocapnic hyperventilation does not alter hepatic hemodynamic parameters in patients with head injury. This result may be related to the lack of changes in cardiac output or in the hepatic vasoreactivity. Moreover, hypocapnia does not modify hepatic-splanchnic oxygenation. Thus, in case of intracranial hypertension, hypocapnia might be used without undesirable effect on the hepatic-splanchnic perfusion.

Adult↗
PubMed1992

Phenylthiocarbamide (PTC) tasting in paranoid and nonparanoid schizophrenic patients.

The present study reports on the association between Phenylthiocarbamide tasting for paranoid and nonparanoid schizophrenic patients. The incidence of PTC tasting is highly variable, and tasters and nontasters are frequently associated with some pathological states. 25 paranoid and 25 nonparanoid schizophrenic patients were examined for their PTC taste sensitivity. Frequency of paranoid tasters resembles the distribution of the normal population, whereas the nonparanoid patients are significantly different in their taste thresholds, with a higher incidence of nontasters. The members of this latter group have twice the incidence of psychiatric illness in their family histories as those of the former group. The significance of these findings is discussed as related to vulnerability for schizophrenia.

Arousal↗
PubMed1989

Effects of physical exercise on peripheral vision and learning in children with spina bifida manifesta.

The purpose of this research was to investigate the effects of active exercise of the arms on various physiological, perceptual, and cognitive parameters of children with spina bifida manifesta who were aged 9 to 12 yr. Following a 5-min. rest interval, subjects were either not exercised (control days) for a 6-min. period or were exercised (experimental days) for a 6-min. period. Cardiac measures, respiratory function, peripheral vision, and figural learning trials were recorded after exercise. Wilcoxon matched-pairs signed rank tests were computed on the means of the exercise and no-exercise conditions for each measure. Six minutes of active exercise resulted in significant increases in peripheral vision, respiratory and cardiac measures and significant decreases in figural learning trials for these children. A floor effect was noted for the figural learning test. It was concluded that exercise increased blood flow through the lungs allowing for greater oxygen diffusion in the brain and other facilitatory effects resulting in more effective cerebral activity. Curriculum revisions for such children seem to indicate the importance of activity in facilitating subsequent learning.

Cerebrospinal Fluid Shunts↗
PubMed1988

Differential performance of acute and chronic schizophrenics in a latent inhibition task.

Differences between acute (N = 26) and chronic (N = 27) schizophrenics diagnosed by Research Diagnostic Criteria and normal controls (N = 53) were examined in a task measuring latent inhibition, i.e., the retardation of learning that normally occurs when a subject forms an association to a stimulus previously repeatedly presented without consequence. In rats, latent inhibition is disrupted by amphetamine and restored by neuroleptics. It was predicted that latent inhibition would be similarly disrupted in acute schizophrenics (presumably in a hyperdopaminergic state) but not in chronic, medicated schizophrenics. Each group was subdivided and assigned randomly to two experimental conditions, preexposure or non-preexposure. Preexposed subjects first heard 30 bursts of white noise through headphones while monitoring a list of nonsense syllables; non-preexposed subjects listened to the nonsense syllables without the white noise. Subjects in both conditions were then given the opportunity to learn that the noise signalled increments in a visually displayed number. Preexposed normals and chronic schizophrenics learned this association more slowly than non-preexposed subjects (latent inhibition); as predicted, acute schizophrenics failed to display this effect. After 6 to 7 weeks, 11 acute and 13 chronic patients were retested; both groups now showed latent inhibition. These results are discussed in relation to the dopamine hypothesis of schizophrenia.

Adult↗
PubMed1984

Personality core dynamics and drug preference.

The aim of this study is to investigate the possible link between Shoham's personality-core theory [1] and addiction to hard drugs. Basing ourselves on Kleinean premises, that the oral stage is critical in the formation of behavioural patterns, which are influential throughout life, we hypothesize that in the oral stage two opposing vectors, 'separation' and 'participation' are initiated. By 'participation' we refer to the identification of ego with an external object or symbol, and continuous tendency to lose the personal identity by fusion with this object or symbol. 'Separation' is the opposite vector and expresses ego's tendency to incorporate the external object or symbol. These vectors form two multidimensional personality axes, on which the different personality types and behavioral patterns can be anchored. This study aims at investigating the connection between these two vectors and drug addiction. We view drug addiction as a functional behaviour pattern, which brings the individual to a state of internal balance. Shoham's personality theory hypothesizes the derivation of behavioural patterns of different personality 'types', according to the strength of the two vector - the 'separant' and 'participant' types. It is hypothesized that the drug use and the experience gained by using the specific drug by different personality types will vary according to the prominence of the core personality vector. The potency of these vectors is related to an early oral (participant) or a later oral (separant) fixation.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1983

Effects of passive physical exercise on peripheral vision in muscular dystrophic children.

To investigate the effects of passive exercise of the extremities on peripheral vision of muscular dystrophic children aged 9 to 13 yr. these subjects were either not exercised (control days) for a 6-min. period or were exercised (experimental days) for a 6-min. period after a 5-min. rest. Peripheral vision was recorded after each condition. Analysis of variance with repeated measures on the exercise and no exercise conditions was computed for each measure. 6 min. of passive exercise significantly increased peripheral vision. It was assumed that exercise increased blood flow through the lungs allowing for greater oxygen diffusion in the brain and other facilitory responses which increased effective cerebral activity. Curriculum revisions for such children indicate the importance of activity in facilitating subsequent learning.

Adolescent↗