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Biomedical subjects

A Rapaport

Publications and source records attributed to A Rapaport.

At least 19 recordsLinked to original sources
PubMed2005

Interval observers for biochemical processes with uncertain kinetics and inputs.

This paper concentrates on the state observation in bioprocesses when there is uncertainty on the process parameters and/or the process inputs. An interval observer is designed on the basis of the cooperativity properties of the model for a standard stirred tank bioreactor model with a single microbial growth and a kinetic model depending on the substrate concentration. Further assumptions are the (lower and upper) boundedness of the specific growth rate and the inlet substrate concentration. Mathematical analysis of the stability and convergence of the interval observer is performed both in absence and in presence of uncertainty on the measurements. It is shown in particular that when the process inputs are known, the static observation error on the unknown state is inversely proportional to one of the observer gains. The performance of the interval observer are also illustrated through numerical simulation.

Bacteria↗
PubMed2005

Robust interval-based regulation for anaerobic digestion processes.

A robust regulation law is applied to the stabilization of a class of biochemical reactors exhibiting partially known highly nonlinear dynamic behavior. An uncertain environment with the presence of unknown inputs is considered. Based on some structural and operational conditions, this regulation law is shown to exponentially stabilize the aforementioned bioreactors around a desired set-point. This approach is experimentally applied and validated on a pilot-scale (1 m3) anaerobic digestion process for the treatment of raw industrial wine distillery wastewater where the objective is the regulation of the chemical oxygen demand (COD) by using the dilution rate as the manipulated variable. Despite large disturbances on the input COD and state and parametric uncertainties, this regulation law gave excellent performances leading the output COD towards its set-point and keeping it inside a pre-specified interval.

Bacteria, Anaerobic↗
PubMed2002

Software sensors for highly uncertain WWTPs: a new approach based on interval observers.

This paper presents the practical implementation of a new robust interval observer on a 1 m3 continuous fixed bed anaerobic reactor used for the treatment of industrial wine distillery wastewater. This interval observer is able to generate guaranteed intervals for the unmeasured variables (i.e. acidogenic and methanogenic bacteria, alkalinity and chemical oxygen demand) from few on-line measurements (i.e. input liquid flow rate, CO2 gaseous flow rate, volatile fatty acids and total inorganic carbon). The main advantage of this approach is its independance with respect to disturbances and uncertainty in the initial conditions, in the kinetics and, last but not least, in the process inputs.

Automation↗
PubMed1994

CSF inositol in schizophrenia and high-dose inositol treatment of schizophrenia.

Inositol is a key metabolite in the phosphatidylinositol cycle, which is a second messenger system for serotonin-2 receptors that have been implicated in the pathophysiology of schizophrenia. Cerebrospinal fluid inositol levels were measured in 20 schizophrenic patients and 19 age- and sex-matched controls and no difference was found. However, the patients were all neuroleptic-treated. A controlled double-blind crossover trial of 12 g daily of inositol for a month in 12 anergic schizophrenic patients, twice the dose given before in schizophrenia, did not show any beneficial effects. However, the number of patients studied was small and the length of time of inositol administration may not have been sufficient.

Adult↗
PubMed1994

Care for chronically ill adolescents.

Too little is known about the nature and extent of physical impairment suffered by adolescents. A recent study in Israel points the way towards more systematic data gathering and analysis, so that the necessary care can be provided.

Adolescent↗
PubMed1993

Inositol treatment raises CSF inositol levels.

Inositol is a key precursor for synthesis of phosphatidylinositol in a major second messenger signalling system. It is biologically active in syndromes such as respiratory distress syndrome but has been thought to be excluded from CNS by the blood-brain barrier. Oral inositol treatment of 8 patients is shown to significantly increase CSF inositol by almost 70%, suggesting possible CNS therapeutic applications of this compound and possible CNS side-effects of systemic therapy.

Adult↗
PubMed1991

Weight gain, increased appetite, and excessive food intake induced by carbamazepine.

Four young patients who developed weight gain induced by carbamazepine therapy are described. The patients received the carbamazepine as anticonvulsant treatment, and soon after starting the drug, abruptly developed an increase in appetite with a concomitant increase in food intake. During a period of 2 months the patients' weights rose by between 7 and 15 kg. Dietary restriction during the carbamazepine treatment was ineffective in promoting weight loss, and loss of the excess weight was achieved only when the drug was discontinued. These patients demonstrate an as yet unpublished adverse effect of carbamazepine. In carbamazepine-induced weight gain, overeating and fat deposition must be taken into consideration as a differential diagnosis to the hitherto described water retention and edema.

Adolescent↗
PubMed1981

Polytetrafluoroethylene (PTFE) grafts for haemodialysis in chronic renal failure: assessment of durability and function at three years.

The utilization of 162 PTFE grafts for angio access in 131 patients over a three year period is reported. One hundred and three new PTFE arterio-venous fistulae were constructed in addition to 59 patch and tube incorporations into pre-existing graft fistulae. At three years, the cumulative patency of newly constructed grafts was 85%. Seventy four per cent of the grafts have had no thrombosis and are functioning up to 38 months following insertion. An aggressive approach was adopted towards the 15% of grafts that had at least one episode of thrombosis prior to flow being successfully restored. Graft occlusion which occurred up to 18 months following insertion, represented 11% of the group in this series. PTFE has provided an important advance in angio access for chronic renal failure with high patency and excellent durability after three years.

Blood Vessel Prosthesis↗
PubMed1977

[Effect of pentobarbital on the biothermic individuality of growing rats and during instrumental conditioning in heat].

At the dosis of 12,5 mg by kg and in 30 growing white rats, pentobarbital acts by shortening the reaction time, by inducing a short period of psychomotor instrumental activity and after a latency of 5 to 20 mn by depressing the total reserve of instrumental activity acquired before this sessions under physiological serum or caffein injections state dependent larning in heat.

Animals↗
PubMed1975

[Instrumental reconditioning at an ambient temperature of 35 +/- 1 degrees C after suppression of the reward in growing rat].

By shortening to 5 seconds the burst of "fresh air" delivered by one level-pressing in 6 or 3 20 minutes sessions of operant conditioning at the ambient temperature of 35 +/- 1 degrees C brings 7 and 3 growing rats up to the maximal value of instrumental acquisition in 2 and 1 sessions. The experiment is going on with 40 minutes sessions in which the first 15 minutes belongs to the reward suppression. In spite of this inhibitory factor there is through the stimulus presence reconditioning which leads to instrumental adaptation at the ambient hyperthermia of 38.5 +/- 0.5 degrees C. At this temperature the instrumental activity level is the same as at 35 +/- 1 degrees C, in 20 minutes and the rectal temperature is rising up to provide compensatory work (+ 2.39 degrees C. instead of + 1.34 degrees C. at 35 +/- degrees C.).

Age Factors↗