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Results for “Process optimization”

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PubMed2007

Kinetic model of a granular sludge SBR: influences on nutrient removal.

A mathematical model was developed that can be used to describe an aerobic granular sludge reactor, fed with a defined influent, capable of simultaneously removing COD, nitrogen and phosphate in one sequencing batch reactor (SBR). The model described the experimental data from this complex system sufficiently. The effect of process parameters on the nutrient removal rates could therefore be reliably evaluated. The influence of oxygen concentration, temperature, granule diameter, sludge loading rate, and cycle configuration were analyzed. Oxygen penetration depth in combination with the position of the autotrophic biomass played a crucial role in the conversion rates of the different components and thus on overall nutrient removal efficiencies. The ratio between aerobic and anoxic volume in the granule strongly determines the N-removal efficiency as it was shown by model simulations with varying oxygen concentration, temperature, and granule size. The optimum granule diameter for maximum N- and P-removal in the standard case operating conditions (DO 2 mg L(-1), 20 degrees C) was found between 1.2 and 1.4 mm and the optimum COD loading rate was 1.9 kg COD m(-3) day(-1). When all ammonia is oxidized, oxygen diffuses to the core of the granule inhibiting the denitrification process. In order to optimize the process, anoxic phases can be implemented in the SBR-cycle configuration, leading to a more efficient overall N-removal. Phosphate removal efficiency mainly depends on the sludge age; if the SRT exceeds 30 days not enough biomass is removed from the system to keep effluent phosphate concentrations low.

Ammonia↗

PubMed1990

Influence of food-environment interactions on health in the twenty-first century.

The quality and safety of foods are affected by the environment, and the quality and safety of the environment are, in turn, affected by foods and food processing. To explore these interrelationships, as they might exist in the twenty-first century, one must speculate regarding future changes in foods and food processing. Several trends in food processing seem likely to predominate into the twenty-first century, and they will be, for the most part, evolutionary in nature and of low consumer visibility. These trends are greater use of foods marketed in a refrigerated state, greater use of irradiation and combination processes, greater automation and optimization of processes, and greater use of biotechnology. It is also reasonable to assume that food products of the following types will increase in importance, namely, those that are convenient (includes eating away from home), those that are tailored to specific dietary needs, those containing chemically modified components such as altered proteins and carbohydrates, and fabricated foods. If these trends in foods and food processes prevail then concern must be directed to the following areas: Microbiological concerns--refrigerated foods; food service operations; new or altered procedures for processing, handling and storing foods; and new foods or food formulations; attention must be given both to controlling known pathogens as well as newly perceived pathogens. Chemical concerns--toxicants occurring naturally in foods; contaminants; chemicals developing in foods during processing, handling and storage; chemicals used in fabricated foods; and chemicals of newly perceived importance, especially those having adverse, covert effects. Several of these chemical concerns are influenced in seriousness by composition of the food environment.

Environmental Health↗

PubMed2005

A cataract decision support system: its requirement is increasing.

Cataract surgery and intraocular lens implantation has taken on many significant advances since its earliest inception. As the prevalence of the aged population increases the number of cataract operations also increases year on year. In the UK last year over 300,000 cataract operations were performed with 2 million in Europe and 1.5 million in the USA. Globally 8.7 million cataract operations are performed per annum. Technical advances are occurring ever more rapidly in this procedure enabling improved preoperative assessment and surgical management. This has produced a sophisticated procedure which is eminently reproducible. In concordance with such improvements both patient and doctors expectations for visual results have also risen. The expectation is now that the operation will achieve more than mere removal of a pathological opacity interfering with the visual process. The possibility and expectation is that the procedure will be tailored specifically to the patient in such a way that the best possible visual result will be achieved through customization of the surgical process to optimize the individual's optical system. Optimization of any particular process may be complex, and cataract surgery is no exception. Careful consideration of many interrelated factors including a patient's functional visual requirements, along with specific anatomical and unique optical factors will be required if an optimum result is to be achieved. The decision making process involved in determining how an individual eye should be surgically customised, can therefore be complicated. These are the situations where decision support systems become most beneficial, to ensure consistent successful results, particularly if technical measurements are being performed by individuals with varying degrees of experience.

Cataract Extraction↗

PubMed2006

Application and utilization of chemoinformatics tools in lead generation and optimization.

The process of Drug Discovery is a complex and high risk endeavor that requires focused attention on experimental hypotheses, the application of diverse sets of technologies and data to facilitate high quality decision-making. All is aimed at enhancing the quality of the chemical development candidate(s) through clinical evaluation and into the market. In support of the lead generation and optimization phases of this endeavor, high throughput technologies such as combinatorial/high throughput synthesis and high throughput and ultra-high throughput screening, have allowed the rapid analysis and generation of large number of compounds and data. Today, for every analog synthesized 100 or more data points can be collected and captured in various centralized databases. The analysis of thousands of compounds can very quickly become a daunting task. In this article we present the process we have developed for both analyzing and prioritizing large sets of data starting from diversity and focused uHTS in support of lead generation and secondary screens supporting lead optimization. We will describe how we use informatics and computational chemistry to focus our efforts on asking relevant questions about the desired attributes of a specific library, and subsequently in guiding the generation of more information-rich sets of analogs in support of both processes.

Chemistry, Pharmaceutical↗

PubMed2004

[Procedure optimization in hospital management].

Starting January 1st 2004 the German diagnosis-related group (DRG) system was established for in-patient cases. Consequently, the detection and realization of cost-saving potentials are becoming more and more important. For a successful future, efficient allocation of resources is essential. Economically, anaesthesia-related time delays during perioperative work-flow should be minimized. Since numerous entities contribute to perioperative care, it is extremely complex to analyze and optimize this process flow. In this publication single steps leading to an optimized perioperative process flow will be presented: documentation of predefined time points, calculation of relevant time intervals and analysis of key numbers for complex settings. Single steps of the given process analysis will be demonstrated using data from surgical patients at the University Hospital Schleswig-Holstein, Campus Kiel. The attached data collection sheets can be used by interested hospital departments and are meant to serve as a template for further process analyses. Based on the shown analysis, an example will be given to develop an optimized work-flow as a standard operating procedure (SOP). The implementation of the SOP module in an interdisciplinary clinical pathway (CP), which defines efficient medical care from admission to discharge, is mainly responsible for decreased process costs but increased quality of care.

Anesthesia Department, Hospital↗

PubMed1989

Optimal formalin fixation and processing schedule of cell blocks from fine needle aspirates.

In fine needle aspiration cytology, cell blocks may provide diagnostic information complementary or additional to that obtained from examination of cell smears. However, the morphological preservation is often unsatisfactory in cell blocks processed by routine schedules used for surgical specimens. This study investigates the effects of different formalin concentrations and processing schedules on cellular morphology. We conclude that 7.5% buffered formalin is the optimal formalin solution and a shortened processing time through xylene is desirable.

Biopsy, Needle↗

PubMed2004

[Optimization of the circulatory percolation process for extraction of radix ginseng rubra].

OBJECTIVE: To optimize the extraction process of Radix Ginseng Rubra. METHODS: The orthogonal test design was used to test the three main factors of circulatory percolation process, including particle size of herb (A), velocity of percolation(B) and time for extraction (C), and the synthetic score basing on obtained rate of ginsenosides Rg1, Re and extraction efficiency was used as guide. RESULTS: The optimum process conditions relevant to the three main factors were as follows. The coarse powder was percolated at a velocity of 0.2 L/min for six hours. CONCLUSION: The circulatory percolation process is better than the reflux process and maceration process for extraction of Radix Ginseng Rubra.

Chromatography, High Pressure Liquid↗

PubMed2000

Optimization of the pelletization process in a fluid-bed rotor granulator using experimental design.

This study examined the effect of rotor speed, amount of water sprayed, and atomizing air pressure on the geometric mean diameter and geometric standard deviation of pellets produced in a fluid-bed rotor granulator using a 23 factorial design and an optimization technique. Pellets were prepared by wet granulation. Equal amounts of microcrystalline cellulose, alpha-lactose monohydrate, and distilled water were used as the granulation liquid. The size and the size distribution of the pellets were determined by sieve analysis. The size of the pellets was found to be dependent on the amount of water added, while an increase in rotor speed decreased their size. Both factors were found to be statistically significant (P <.05). The effect of atomizing air pressure on pellet size was not statistically significant. None of the 3 factors significantly affected the geometric standard deviation of the pellets. The rotor speed and the amount of water sprayed were further selected in order to construct a mathematical model that correlates these factors with the geometric mean diameter of the pellets. For this purpose, the optimization technique 3(2) was used. The derived equation described the relationship between the selected factors and the size of the pellets. As a result, the experimental design techniques applied were found to be suitable in optimizing the pelletization process carried out in a fluid-bed rotor granulator.

Drug Compounding↗

PubMed2003

Characterization and optimization of a chromatographic process based on ethylenediamine-N,N,N',N'-tetra(methylphosphonic) acid-modified zirconia particles.

The primary objective of work was to characterize, optimize and model a chromatographic process based on ethylenediamine-N,N,N',N'-tetra(methylphosphonic) acid (EDTPA)-modified zirconia particles. Zirconia particles were produced by spray-drying colloidal zirconia. Zirconia spheres produced were further classified, calcined and modified with EDTPA to yield a solid-phase support for use in bio-chromatography (r_PEZ). Specifically, the ability of r_PEZ to selectively bind and enrich IgG, IgA, and IgM from biological fluids was evaluated and demonstrated. To better understand the force of interaction between the IgG and the r_PEZ, the equilibrium disassociation constant (K(d)) was determined by static binding isotherms, as a function of temperature and by frontal analysis at different linear velocities. The maximum static binding capacity (Q(max)) was found to be in the range 55-65 mg IgG per ml of beads, and unaffected by temperature. The maximum dynamic binding capacity (Q(x)) was found to be in the range 20-12 mg IgG per ml of beads. The adsorption rate constant (k(a)) was determined by a split-peak approach to be between 982 and 3242 l mol(-1) s(-1) depending on the linear velocity. The standard enthalpy and entropy values were estimated for this interaction of IgG with this novel support.

Chromatography, Liquid↗

PubMedDate not supplied

Monitoring of recombinant protein production using bioluminescence in a semiautomated fermentation process.

On-line optimization of fermentation processes can be greatly aided by the availability of information on the physiological state of the cell. The goal of our "BioLux" research project was to design a recombinant cell capable of intracellular monitoring of product synthesis and to use it as part of an automated fermentation system. A recombinant plasmid was constructed containing an inducible promoter that controls the gene coding for a model protein and the genes necessary for bioluminescence. The cells were cultured in microfermenters equipped with an on-line turbidity sensor and a specially designed on-line light sensor capable of continuous measurement of bioluminescence. Initial studies were done under simple culture conditions, and a linear correlation between luminescence and protein production was obtained. Such specially designed recombinant bioluminescent cells can potentially be applied for model-based inference of intracellular product formation, as well as for optimization and control of recombinant fermentation processes.

Bioreactors↗

PubMed2002

[Studies on extraction process of Radix Platycodi].

The orthogonal design was used to optimize the extraction process of Radix Platycodi with content of total saponin and yield of the extract as markers. Factors that have been chosen were alcohol concentration, alcohol consumption, extraction times and extraction time. Each factor has three levels. The result showed that the optimum extraction condition obtained was 70% alcohol, 3 times the amount of material, refluxing for 5 times, 60 minutes each time, the optimized process was stable and workable.

Drugs, Chinese Herbal↗

PubMed2004

[Optimization of the extraction process in the traditional preparation of Baohe Wan].

OBJECTIVE: To study the extraction process for reforming the traditional preparation process of Baohe Wan. METHOD: Using the recovery rate of total flavonoids of Baohe Wan and pharmacodynamic effects as indices, different extraction processes were compared. RESULTS: Supercritical carbon dioxide fluid extraction combined with water extraction was optimal for the extraction, and the extract prepared by the new process was pharmacodynamically more potent than the original Baohe Wan, as demonstrated by the rate of carbon powder moving in the small intestine and stomach emptying rate in mice. CONCLUSION: Supercritical carbon dioxide fluid extraction combined with water extraction is practical for optimizing the preparation of Baohe Wan.

Animals↗

PubMed2006

Optimization of the electrocoagulation process for the removal of copper, lead and cadmium in natural waters and simulated wastewater.

Chemical, electrochemical and flow variables were optimized to examine the effectiveness of the electrocoagulation process for the removal of copper, lead and cadmium. The electrochemical process, which uses electrodes of commercial laminate steel, was applied to simulated wastewater containing 12 mg dm(-3) of copper, 4 mg dm(-3) of lead and 4 mg dm(-3) of cadmium. The optimum conditions for the process were identified as pH=7, flow rate=6.3 cm(3) min(-1) and a current density between 31 and 54 A m(-2). When the electrode geometric area and time of electrolysis reached critical values, the copper removal reached a maximum value of 80%. A linear relationship was identified between the current density and the mass of generated sludge. In addition, a linear relationship was found between specific energy consumption and current density. The results of this investigation provide important data for the development of an industrial-scale electrolytic reactor.

Electrolysis↗

PubMed2004

Optimizing the fMRI data-processing pipeline using prediction and reproducibility performance metrics: I. A preliminary group analysis.

We argue that published results demonstrate that new insights into human brain function may be obscured by poor and/or limited choices in the data-processing pipeline, and review the work on performance metrics for optimizing pipelines: prediction, reproducibility, and related empirical Receiver Operating Characteristic (ROC) curve metrics. Using the NPAIRS split-half resampling framework for estimating prediction/reproducibility metrics (Strother et al., 2002), we illustrate its use by testing the relative importance of selected pipeline components (interpolation, in-plane spatial smoothing, temporal detrending, and between-subject alignment) in a group analysis of BOLD-fMRI scans from 16 subjects performing a block-design, parametric-static-force task. Large-scale brain networks were detected using a multivariate linear discriminant analysis (canonical variates analysis, CVA) that was tuned to fit the data. We found that tuning the CVA model and spatial smoothing were the most important processing parameters. Temporal detrending was essential to remove low-frequency, reproducing time trends; the number of cosine basis functions for detrending was optimized by assuming that separate epochs of baseline scans have constant, equal means, and this assumption was assessed with prediction metrics. Higher-order polynomial warps compared to affine alignment had only a minor impact on the performance metrics. We found that both prediction and reproducibility metrics were required for optimizing the pipeline and give somewhat different results. Moreover, the parameter settings of components in the pipeline interact so that the current practice of reporting the optimization of components tested in relative isolation is unlikely to lead to fully optimized processing pipelines.

Adult↗

PubMed2006

Beyond the face: exploring rapid influences of context on face processing.

Humans optimize behavior by deriving context-based expectations. Contextual data that are important for survival are extracted rapidly, using coarse information, adaptive decision strategies, and dedicated neural infrastructure. In the field of object perception, the influence of a surrounding context has been a major research theme, and it has generated a large literature. That visual context, as typically provided by natural scenes, facilitates object recognition as has been convincingly demonstrated (Bar, M. (2004) Nat. Rev. Neurosci., 5: 617-629). Just like objects, faces are generally encountered as part of a natural scene. Thus far, the facial expression literature has neglected such context and treats facial expressions as if they stand on their own. This constitutes a major gap in our knowledge. Facial expressions tend to appear in a context of head and body orientations, body movements, posture changes, and other object-related actions with a similar or at least a closely related meaning. For instance, one would expect a frightened face when confronted to an external danger to be at least accompanied by withdrawal movements of head and shoulders. Furthermore, some cues provided by the environment or the context in which a facial expression appears may have a direct relation with the emotion displayed by the face. The brain may even fill in the natural scene context typically associated with the facial expression. Recognition of the facial expression may also profit from processing the vocal emotion as well as the emotional body language that normally accompany it. Here we review the emerging evidence on how the immediate visual and auditory contexts influence the recognition of facial expressions.

Electroencephalography↗

PubMed2005

A geometrically based method of step and shoot stereotactic radiosurgery with a miniature multileaf collimator.

Conventional methods of inverse planning for intensity-modulated radiotherapy (IMRT) and intensity-modulated radiosurgery (IMRS) are generally based upon optimizing a set of beam fluence profiles according to a set of dose-volume constraints specified by a human planner. This optimization is generally carried out through an iterative approach that relies upon the optimization of a score, driving the plan's ability to satisfy the user-provided constraints. Following optimization of the fluence distribution, the non-trivial problem of converting the fluence distribution into a set of deliverable, intensity-modulated beams must be solved. A novel approach to solving this IMRS total inverse problem is presented in this paper. The proposed method uses a class solution that provides an optimized dose gradient and a method of designing a conformal plan based on an existing geometrically based optimization algorithm. After developing an optimal fluence distribution, the process then arranges the fluence into a set of simple and efficient MLC beam delivery sequences. The algorithm presented here offers several potential advantages for the application of intensity modulation to radiosurgery treatment planning. The geometrically based optimization process' simplicity requires far less human user input and decision making in the specification of dose and dose-volume constraints than do conventional inverse planning algorithms. This simplicity allows the optimization process to be completed much faster than conventional inverse-planning algorithms, literally seconds compared with at least several minutes. Likewise, the fluence conversion step is a simplified process (compared to conventional IMRT planning), which takes advantage of some simplifications uniquely appropriate to the problem at hand (IMRS). The converted, deliverable IMRS beams allow superior conformity and dose gradient relative to conventional IMRS planning or 3DCRT radiosurgery planning. Another benefit is that the number of beam intensity levels is greatly reduced, from hundreds to as few as a half-dozen intensity levels. Finally, since the treatment plan optimization process is based upon proven principles applicable to optimizing radiosurgery (rather than the general problem of optimizing fractionated radiotherapy plans), the plans generated and deliverable with this method of IMRS are potentially superior to those produced by conventional inverse-planning methods of IMRT/IMRS.

Algorithms↗

PubMed2006

The patient's vulnerability, dependence and exposed situation in the discharge process: experiences of district nurses, geriatric nurses and social workers.

AIM: The aim of the study was to obtain a deeper understanding of the experiences of the discharge process among different professionals. BACKGROUND: An optimal discharge process for hospitalized elderly to other forms of care is of crucial importance, especially since health and medical policies encourages shorter hospital stays and increased healthcare service in outpatient care. METHODS: Nurses and social workers from inpatient care, outpatient care, municipal care and social services were interviewed. Eight focus-group interviews with a total of 31 persons were conducted. The subsequent analyses followed a phenomenological approach. RESULTS: The findings revealed three themes, Framework, Basic Values and Patient Resources, which influenced the professionals' actions in the discharge process. The overall emerging structure comprised the patient's vulnerability, dependence and exposed situation in the discharge process. CONCLUSION: In conclusion some factors are of special importance for the co-operation and the actions of professionals involved in the discharge process. Firstly, a distinct and common framework, with conscious and organizationally based values. Secondly the need to take the patient resources into consideration. Together these factors could contribute to secure the patients involvement in the discharge process and to design an optimal, safe and good care. RELEVANCE TO CLINICAL PRACTICE: Collaborative approaches among a range of professionals within a variety of organizations are common, especially in the care of the elderly. The role and support of both the organizations and the educational units are decisive factors in this area.

Activities of Daily Living↗

PubMed2002

Optimizing conditions for thermal processes of soy milk.

Mathematical and kinetic models were set up for heat-induced quality changes in soy milk, including inactivation of trypsin inhibitor activity (TIA) and degradation of thiamin, riboflavin, color, and flavor over a wide range of time-temperature combinations with particular interest in the ultrahigh-temperature (UHT) range. On the basis of these models, multiresponse optimization of the thermal processes for soy milk was carried out to obtain the following effects simultaneously: (1) maximum destruction of bacterial spores, (2) maximum inactivation of TIA, and (3) minimum degradation of sensory and nutritional qualities. By a suitable selection of high temperatures and extended heating times, for example, 143 degrees C/60 s, it is possible to use a single-step UHT process to produce a commercially sterile soy milk with satisfactory TIA inactivation, highly acceptable color and flavor, and thiamin retention between 90 and 93%.

Beverages↗