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Results for “Process optimization”

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PubMedDate not supplied

A possible approach for discrimination between normal and pathological signals using the WFLC algorithm.

The discrimination between normal and pathological tremor is difficult when amplitude is relatively small. The WFLC algorithm, a time domain adaptive Fourier transform, is designed to control physiological tremor and to improve precision during microsurgery. We added two iterative optimization processes to initialize the following parameters: initial frequency weight (omega0), amplitude adaptation rate (mu) and frequency adaptation rate (mu0). Then, we applied the methods on data sets recorded on patients with different tremors (control, parkinsonian, cerebellar, and essential) sampled at 200 Hz. After filtering the data, the WFLC algorithm tracked the time-varying dominant frequencies and amplitudes of the transformed data sets. Our results illustrate the potential of using this algorithm as an approach to discriminate between normal and pathological signals even when amplitude is not a significant discriminating factor.

Algorithms↗

PubMed2001

[Optimization of aerosol therapy in otorhinolaryngology: stability and granulometry of dexamethasone-gomenol-framycetin solution].

Nebulization of solutions associating gomenol, dexamethasone and framycetin is very widespread in otorhinolaryngology (particularly for the treatment of actue laryngitis and post-traumatic laryngitis and rhinitis and for the tracheotomy care). A rigorous clinical evaluation is however lacking. The aim of this work was to evaluate use of such solutions in comparison with the recommendations issuing from the National Session in April 1997 on good practices for aerosol therapeutics. Stability and granulometry were studied in order to optimize processing. A new formulation and new technical methods of administration are proposed in relation to the results of this study and the national recommendations.

Aerosols↗

PubMedDate not supplied

[Optimization of the process of culturing yeast in the presence of the dispersed mineral palygorskite].

A positive effect from introduction of the highly dispersed mineral palygorskite in the nutrient medium for aerobic batch cultivation of the yeast Saccharomyces cerevisiae, the Kyivsky strain, used in production of champagne has been established experimentally. An adequate mathematical model describing the process of growth has been constructed. Optimal cultivation conditions have been determined which provided for the achievement of such yeast cell concentration in the culture fluid as 116 mln/ml, palygorskite concentration in the nutrient medium being 0.37 g/l and sucrose 2.0 +/- 0.2%. The yeast obtained possess higher fermentation activity.

Culture Media↗

PubMed2001

Modeling of organic pollutant destruction in a stirred-tank reactor by ozonation.

Destruction of organic contaminants in water by ozonation is a gas-liquid process which involves ozone mass transfer and fast irreversible chemical reactions. Ozonation reactor design and process optimizing require the modeling of the gas-liquid interactions within the reactor. In this paper a theoretical model combining the fluid dynamic and reaction kinetic parameters is proposed for predicting the destruction rates of organic pollutants in a semi-batch stirred-tank reactor by ozonation. A simple expression for the enhancement factor as our previous work has been applied to evaluate the chemical mass transfer coefficient in ozone absorption, 2,4-dichlorophenol (2,4-DCP) and 2,6-DCP or their mixture are chosen as the model compounds for simulating, and the predicted DCP concentrations are compared with some measured data.

Absorption↗

PubMed2002

Developing partnership promotes peace: group psychotherapy experiences.

Partnerships are often optimal processes for interpersonal growth. The ability to have and keep a partner in mind should, therefore, be thought about and learnt. Although reciprocity, some symmetry, and mutual give and take are important aspects of partnerships, this article emphasizes a partners ability to process difficulties for the other as an aid to growth. The containment and elaboration of distress in partnerships is discussed using three examples of such potential relationships. The emotional beginning of a partnership, whether starting from love, working relationship or from hate, is the focus of the article. Individual, dyadic, and group aspects as separation-individuation and containment processes are described as contributing to partnership-building. The ability of a therapy group to process splitting and projecting phenomena are discussed. Co-therapists seem to have to work through painful conflicts between themselves to develop the therapists' containment abilities inside a functional partnership. Supervision may help process these emotional hardships. Within families, mothers could contribute to a better processing of their sons violence shared through infant dreams, which represent an effort to cope with inner and outer aggression. Growth-promoting aspects of dream telling as potential partnerships in families and groups are discussed. Finally, partnership building between hating foes is exemplified by the efforts made by participants in Israeli and Palestinian peace dialogues. In groups, interpersonal development may be furthered by helping participants mutually contain and be contained, enabling partnership opportunities to grow after love and sympathy are over.

Conflict, Psychological↗

PubMed2003

The effect of GAOs (glycogen accumulating organisms) on anaerobic carbon requirements in full-scale Australian EBPR (enhanced biological phosphorus removal) plants.

Glycogen-accumulating organisms (GAOs) were present in six full-scale plants investigated and in all but one made a significant contribution to the amount of volatile fatty acid (VFA) taken up anaerobically. While most plants surveyed contain GAOs, it was demonstrated that it is possible for a full-scale plant to operate with an insignificant GAO population. "Candidatus Accumulibacter phosphatis" were the significant polyphosphate-accumulating organisms (PAOs) in all plants surveyed. "Candidatus Competibacter phosphatis" were found in all plants along with other possible GAOs that were observed but not identified. A significant GAO population will increase the carbon requirements by removing VFA that could otherwise have been used by PAOs. Process optimization minimizing GAOs in full-scale plants would lead to a more efficient use of VFA.

Bioreactors↗

PubMed2002

[Direct determination of trace element arsenic in high purity nickel by GFAAS].

Determination of trace element arsenic in high purity nickel by GFAAS in STPF conditions is described in this paper. The dry time, ashing temperature and atomization temperature are obtained by optimization process. The standard solutions are matched to eliminate the influences of matrix nickel, and nickel is also as the chemical matrix modifier in the detected. The characteristic mass of the method is 1.9 pg, the average relative standard deviation is 1.4%, the recovery rate is in the range of 95%-103%.

Arsenic↗

PubMed2003

Predicting ADME properties and side effects: the BioPrint approach.

Computational methods are increasingly used to streamline and enhance the lead discovery and optimization process. However, accurate prediction of absorption, distribution, metabolism and excretion (ADME) and adverse drug reactions (ADR) is often difficult, due to the complexity of underlying physiological mechanisms. Modeling approaches have been hampered by the lack of large, robust and standardized training datasets. In an extensive effort to build such a dataset, the BioPrint database was constructed by systematic profiling of nearly all drugs available on the market, as well as numerous reference compounds. The database is composed of several large datasets: compound structures and molecular descriptors, in vitro ADME and pharmacology profiles, and complementary clinical data including therapeutic use information, pharmacokinetics profiles and ADR profiles. These data have allowed the development of computational tools designed to integrate a program of computational chemistry into library design and lead development. Models based on chemical structure are strengthened by in vitro results that can be used as additional compound descriptors to predict complex in vivo endpoints. The BioPrint pharmacoinformatics platform represents a systematic effort to accelerate the process of drug discovery, improve quantitative structure-activity relationships and develop in vitro/in vivo associations. In this review, we will discuss the importance of training set size and diversity in model development, the implementation of linear and neighborhood modeling approaches, and the use of in silico methods to predict potential clinical liabilities.

Animals↗

PubMed2000

[Determination of micro amounts of calcium and magnesium in saturated high purity sodium chloride solution by FAAS].

Micro amounts of calcium and magnesium in saturated high purity sodium chloride solution were determined by flame atomic absorption spectrometry after the preseparation of calcium and magnesium from matrix solution through ion-exchange resin column filled with model 401 chelate resin. The parameters and operating conditions of the preseparation of calcium and magnesium from matrix solution were studied by orthogonal optimization process. The relative standard deviations of this method were 6.5% and 5.5% for calcium and magnesium, respectively. The recoveries were 99% and 94% for calcium and magnesium, respectively.

Calcium↗

PubMed1992

Strategies for automated sequencing of human mitochondrial DNA directly from PCR products.

A rapid, robust and sensitive method has been developed for the amplification and direct sequencing of human mitochondrial DNA. A 403-bp hypervariable segment was amplified by two successive rounds of nested PCR. This was then sequenced by the dideoxy chain termination method using dye-labeled universal sequencing primers in conjunction with an automated DNA sequencer. This paper describes the assessment of four different strategies for this amplification and sequencing process. Optimal results were obtained by immobilizing the biotinylated PCR product on Dynabeads followed by solid-phase sequencing with Sequenase. Degraded samples and those containing trace amounts of DNA such as extracts from hair shafts can be analyzed by this method.

Automation↗

PubMed1990

Suspension culture of mammalian cells.

Mammalian cell suspension culture systems are being used increasingly in the biotechnology industry. This is due to their many advantages including simplicity and homogeneity of culture. Suspension systems are very adaptable (e.g., for microcarrier, microencapsulation, or other methods of culture). Their engineering is thoroughly understood and standardized at large scale, and automation and cleaning procedures are well established. Suspension systems offer the possibility of quick implementation of production protocols due to their ability to be scaled easily once the basic culture parameters are understood. The only main disadvantage of the suspension culture systems to date is their inapplicability for the production of human vaccines from either primary cell lines or from normal human diploid cell lines (Hayflick et al., 1987 and references therein). One of the great advantages of suspension culture is the opportunity it provides to study interactions of metabolic and production phenomena in chemostat or turbidostat steady-state systems. Furthermore, in suspension culture systems from which cell number and cell mass measurements are easy to obtain, rigorous and quantitative estimations of the effects of growth conditions or perturbations of metabolic homeostasis can be made. Such studies can speed up the development of optimal processes. With our increasing understanding of factors influencing expression in mammalian cells (Cohen and Levinson, 1988; Santoro et al., 1988) and the direct application of new methods in suspension culture (Rhodes and Birch, 1988), its usefulness and importance is likely to increase in the future. In this chapter, we have described some of the potential uses of the various suspension culture systems and have covered most of the established technology and literature. Due to the rapid developments and needs in the biotechnology industry and the versatility of suspension culture systems, it is probable that many more variations on this theme will evolve in the near future at both the pilot and production scales.

Animals↗

PubMed2003

Oxidation of phosphorus compounds by Fenton's reagent.

In the present work a Fenton's treatment for the oxidation of a phosphorous compounds mixture, simulating a match manufacturing industry wastewater, were studied. Experimental tests were performed on three sample solutions at a phosphorus concentration of 250, 500 and 750 mg/l. In each solution an equal amount of sodium phosphite and sodium hypophosphite was dissolved. The investigation of pH, temperature and reagents ratio on the oxidation rate led to the individuation of the optimal process operating conditions. The results show that Fenton's reagent provides a powerful conversion to phosphate of the phosphorous solution. In particular at pH=3.5 and 20 degrees C a residual concentration of non oxidized phosphorus in compliance with the Italian regulation limits for industrial wastewater disposal. Tests performed on sample solution of 500 mg/l P and 750 mg/l P by adding hydrogen peroxide and bivalent iron in three sequential steps led to similar reaction efficiencies to tests carried out adding both Fenton's reagents in one step, but with a remarkably lower reagents consumption.

Hydrogen Peroxide↗

PubMed2003

[The utility boiler low NOx combustion optimization based on ANN and simulated annealing algorithm].

With the developing restrict environmental protection demand, more attention was paid on the low NOx combustion optimizing technology for its cheap and easy property. In this work, field experiments on the NOx emissions characteristics of a 600 MW coal-fired boiler were carried out, on the base of the artificial neural network (ANN) modeling, the simulated annealing (SA) algorithm was employed to optimize the boiler combustion to achieve a low NOx emissions concentration, and the combustion scheme was obtained. Two sets of SA parameters were adopted to find a better SA scheme, the result show that the parameters of T0 = 50 K, alpha = 0.6 can lead to a better optimizing process. This work can give the foundation of the boiler low NOx combustion on-line control technology.

Algorithms↗

PubMed2004

Computational chemogenomics approaches to systematic knowledge-based drug discovery.

Chemogenomics, the identification of all possible drugs for all possible targets, has recently emerged as a new paradigm in drug discovery in which efficiency in the compound design and optimization process is achieved through the gain and reuse of targeted knowledge. As targeted knowledge resides at the interface between chemistry and biology, computational tools aimed at integrating the chemical and biological spaces play a central role in chemogenomics. This review covers the recent progress made in integrative computational approaches to data annotation and knowledge generation for the systematic knowledge-based design and screening of chemical libraries.

Chemistry, Pharmaceutical↗

PubMed2004

Microwave-enhanced medicinal chemistry: a high-speed opportunity for convenient preparation of protease inhibitors.

The unique properties of microwave in situ heating offer unparalleled opportunities for medicinal chemists to accelerate lead optimization processes in early drug discovery. The technology is ideal for palladium-catalyzed alteration chemistry as it allows for complete control over reactions, with the use of non-inert conditions, providing high chemoselectivity and rapid feedback. To illustrate the advantages of this methodology, we describe our applications and approaches for the rapid synthesis of novel aspartyl protease inhibitors using dedicated microwave equipment. Biological results from chemical studies of the different side-chain positions of HIV-1 and malarial plasmepsin I and II protease inhibitors are summarized.

Aspartic Acid Endopeptidases↗

PubMed2004

[Recent developments in radiotherapy of hepatocellular carcinoma].

With the accumulation of clinical experiences, the efficacy of radiotherapy has been recognized in management scheme for HCC. While hepatologists are beginning to show less reluctance for applying radiotherapy to the treatment of HCC, it is necessary that the hepatologists be informed of the rapid developments in technical strategy for radiation oncology. Recent advances in several technologies have opened a new era in radiation oncology. Modern imaging technologies can provide a 3-dimensional model of patient's anatomy, and this allows radiation oncologists to identify accurate tumor volumes as well as the tumors' relationship with the adjacent normal tissues. Moreover, the development of the computer-controlled multileaf collimator systems now enables physicians to perform precise beam shaping and to modulate the radiation dose distribution. A combination of these systems, 3-DCRT, is rapidly replacing the more conventional 2-D radiotherapy. 3-DCRT has evolved into a more sophisticated technology, intensity modulated radiotherapy (IMRT). In IMRT, with the powerful computer-aided optimization process, the radiation dose can be delivered to the target using highly complex isodose profiles. This new technology has been further developed into IGRT, which combines the CT-images scanning system and radiation equipments into one hardware package, and this system is currently ready for clinical application. In parallel with the radiation technologies described above, the strategy of stereotactic radiation has evolved from the conventional linear accelerator-based system to a gammaknife, and more recently, to a cyberknife. These systems are primarily based on the concept of radiosurgery. Currently, various radiation technologies have been adopted for the radiotherapy of HCC. In this article, each strategy will be discussed as well as the indications for radiotherapy and the radiation-related complications.

Carcinoma, Hepatocellular↗

PubMed2004

[Rapid determination of trace Sb in plastic pipes for dringing water by GFAAS].

A new method for the determination of trace Sb in plastic pipes for drinking water was found. Cu is used as a matrix modifier in the transverse-orientation Zeeman background dedution GFAAS to determine trace Sb in plastic pipes for drinking water rapidly. The ashing temperature and atomization temperature were obtained by optimization process. The influences of medium acidity were studied. The best measurement conditions were selected. The sensitivity and precision of the method were improved. Sb was detected directly with a linear range of 0.27-20.0 microg x L(-1). The equation of working curve is Y = 0.0068X - 0.0002, r = 0.9996. The characteristic mass of the method is 6.7 pg. The detection limit is 5.4 pg. The recovery is 92.2%-102.5%. The RSDs were obtained from the data of 6 determinations at the concentration level of 5.0, 10.0 and 20.0 microg x L(-1) is 6.47%, 4.97% and 2.45% respectively. The method is simple, rapid, accurate and of highly sensitive and precise. Satisfactory results are obtained.

Alkanesulfonic Acids↗

PubMed2001

Carbon and complex nitrogen source selection for secondary metabolite cultivation at the pilot scale.

The fermentation of desmethyl-asterriquinone B-1, a diabetes target, by a Pseudomonasarias species was conducted at the 600-l scale using a revised complex medium containing yeast extract and soy hydrolysate. Oat flour and tomato paste were removed from this medium due to difficulties in sterilization. An initial cerelose charge of 40 g/l improved titer and reduced product degradation in the broth at cultivation conditions. An initial mannitol concentration of 65 g/l effectively avoided mid-cycle mannitol additions necessary for the 40 g/l mannitol concentration without the reduction in productivity seen at 90 g/l mannitol. These additions diluted the broth because of the low aqueous solubility of mannitol. Titers reached 3.0 g/l after 158 h with an optimized process, increasing two-fold from the original medium and operating conditions. Reproducible foaming occurred at the point of glucose exhaustion when the culture switched to mannitol consumption. Use of alternative carbon sources (glycerol, soybean oil, sorbitol in conjunction with cerelose) was not effective in attaining similar productivity and did not reduce the extent of foaming. In the case of fructose, the extent of foaming was markedly reduced but product formation was negligible.

Journal Article↗