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Online Monitoring (online + monitoring)
Selected AbstractsHigh-Throughput Investigation of Polymerization Kinetics by Online Monitoring of GPC and GCMACROMOLECULAR RAPID COMMUNICATIONS, Issue 1 2004Richard Hoogenboom Abstract Summary: Gel permeation chromatography (GPC) and gas chromatography (GC) were successfully introduced into a high-throughput workflow. The feasibility and limitations of online GPC with a high-speed column was evaluated by measuring polystyrene standards and comparison of the results with regular offline GPC measurements. The reliability of the online GC characterization was investigated by monitoring the cationic ring-opening-polymerization of 2-ethyl-2-oxazoline, whose polymerization kinetics were determined by both online and offline GC. [source] Continuous Subcutaneous Glucose Monitoring System in diabetic mothers during labour and postnatal glucose adaptation of their infantsDIABETIC MEDICINE, Issue 4 2008E. Stenninger Abstract Aims To assess a new technique for continuous monitoring of glucose concentration during labour in diabetic mothers. A second objective was to study maternal glucose levels in relation to postnatal glucose adaptation and the need for intravenous (IV) glucose treatment in the newborn infant. Methods Fifteen pregnant women with insulin-treated diabetes mellitus participated in this prospective pilot study. To measure their glucose control during labour we used the Continuous Subcutaneous Glucose Monitoring System (CGMS; Medtronic, Minneapolis, MN, USA) to calculate the mean glucose concentration and the area under the curve (AUC) in the last 120 min before delivery. All infants of these women were transferred to the neonatal care unit for early oral feeding and blood glucose measurements up to 14 h after delivery. Infants received IV glucose if blood glucose values were repeatedly < 2.2 mmol/l. Results All women coped well with the CGMS monitoring. AUC 0,120 min before delivery, mean glucose concentration 0,120 min before delivery and cord plasma insulin level were all significantly associated with the need for IV glucose in the newborn children. Conclusions In this study we found an association between maternal glucose concentrations during labour and postnatal glucose adaptation and need for IV glucose treatment in the infants. Online monitoring of glucose levels during delivery might help us to achieve maternal normoglycaemia and further reduce the risk of postnatal hypoglycaemia in the offspring. [source] Prescription drug misuse: Is technology friend or foe?DRUG AND ALCOHOL REVIEW, Issue 1 2009SUZANNE NIELSEN Abstract Introduction and Aims. Prescription drug misuse and related harms have been increasing considerably over the past decade. At the same time, there has also been rapid growth in the use of online and Internet technologies. Thus, it is important that we understand the role online and Internet technologies play in prescription drug misuse. Design and Methods. Published work addressing the role of technology in prescription drug misuse is explored. Topics include: Internet supply, online monitoring of prescription drug use trends and electronic prescription monitoring. Results. Little is known about the prevalence of acquiring prescription drugs from online pharmacies. Prescription drugs are easily accessible through vendor websites, and ,rogue' no-prescription websites have proven difficult to control. There has so far been limited application of real-time monitoring to prevent overuse of prescription medications. Online monitoring of drug use trends may also prove to be a useful and timely source of information about new methods of ,off-label' prescription drug use. Discussion and Conclusions. Technology has the potential to play a more prominent role in facilitating drug acquisition, while also enhancing the monitoring and prevention of prescription drug misuse. As technology becomes more ubiquitous in everyday life, the continued investigation of its relationship with prescription drug misuse becomes even more important.[Nielsen S, Barratt MJ. Prescription drug misuse: Is technology friend or foe? Drug Alcohol Rev 2009;28:81,86] [source] Monitoring of Emulsion Polymerisation Processes using Ion Mobility Spectrometry,A Pilot StudyMACROMOLECULAR REACTION ENGINEERING, Issue 2-3 2009Wolfgang Vautz Abstract Online monitoring of monomer concentrations in (semi-) batch emulsion polymerisation reactors is important for safe and cost-efficient operation of production plants. In the present pilot study, ion mobility spectrometry was applied for monitoring the concentration during emulsion polymerisation of vinyl acetate (VA) using UV light for ionisation of the headspace of a continuous sample flow. Satisfactory sensitivity for online process monitoring of the monomer concentration in the reactor was observed (LOD 400 ng,·,L,1 air, equivalent to <1%). Furthermore, it is possible to discriminate between VA and other common monomers [butyl acrylate (BA), methyl methacrylate (MMA)]. Using the more efficient , -radiation ionisation, monomer concentration could be measured even in the final latex as a measure of the final product properties. [source] Online monitoring of crevice corrosion with electrochemical noiseMATERIALS AND CORROSION/WERKSTOFFE UND KORROSION, Issue 10 2004G. Schmitt Abstract The time-related cumulated noise charges extracted from the noise signals between two "identical" crevice electrodes yield a direct quantitative easy-to-interpret information on time-related corrosion intensities in the crevice. A new software-assisted method of noise data evaluation allows a "counting of coulombs" exchanged between the system electrodes, the results of which directly correlate with the metal dissolution intensity in the crevice. The versatility of this "CoulCount" method is demonstrated in a failure analysis on the cause of crevice corrosion at spigots of automotive cooling water pumps. Echzeitüberwachung von Spaltkorrosion durch Elektrochemisches Rauschen Zeitbezogene Gesamtrauschladungsmengen, welche aus den Rauschsignalen zwischen zwei "identischen" Spalteleltroden gewonnen werden können, liefern einfach zu interpretierende Informationen über die zeitbezogene Korrosionsintensität im Spalt. Eine neue, Software-unterstützte Methode der Rauschdatenauswertung erlaubt das Zählen der Ladungen, die zwischen den Systemelektroden ausgetauscht werden. Das Ergebnis korreliert direkt mit der Metallauflösungsintensität im Spalt. Die vielseitige Anwendbarkeit dieser "CoulCount-Methode" wird am Beispiel einer Schadensanalyse zur Ursache der Spaltkorrosion an Stutzen von Automobilwasserpumpen demonstriert. [source] Prescription drug misuse: Is technology friend or foe?DRUG AND ALCOHOL REVIEW, Issue 1 2009SUZANNE NIELSEN Abstract Introduction and Aims. Prescription drug misuse and related harms have been increasing considerably over the past decade. At the same time, there has also been rapid growth in the use of online and Internet technologies. Thus, it is important that we understand the role online and Internet technologies play in prescription drug misuse. Design and Methods. Published work addressing the role of technology in prescription drug misuse is explored. Topics include: Internet supply, online monitoring of prescription drug use trends and electronic prescription monitoring. Results. Little is known about the prevalence of acquiring prescription drugs from online pharmacies. Prescription drugs are easily accessible through vendor websites, and ,rogue' no-prescription websites have proven difficult to control. There has so far been limited application of real-time monitoring to prevent overuse of prescription medications. Online monitoring of drug use trends may also prove to be a useful and timely source of information about new methods of ,off-label' prescription drug use. Discussion and Conclusions. Technology has the potential to play a more prominent role in facilitating drug acquisition, while also enhancing the monitoring and prevention of prescription drug misuse. As technology becomes more ubiquitous in everyday life, the continued investigation of its relationship with prescription drug misuse becomes even more important.[Nielsen S, Barratt MJ. Prescription drug misuse: Is technology friend or foe? Drug Alcohol Rev 2009;28:81,86] [source] On-column conductivity detection in capillary-chip electrophoresisELECTROPHORESIS, Issue 24 2007Zhi-Yong Wu Professor Abstract On-column conductivity detection in capillary-chip electrophoresis was achieved by actively coupling the high electric field with two sensing electrodes connected to the main capillary channel through two side detection channels. The principle of this concept was demonstrated by using a glass chip with a separation channel incorporating two double-Ts. One double-T was used for sample introduction, and the other for detection. The two electrophoresis electrodes apply the high voltage and provide the current, and the two sensing electrodes connected to the separation channel through the second double-T and probe a potential difference. This potential difference is directly related to the local resistance or the conductivity of the solution defined by the two side channels on the main separation channel. A detection limit of 15,,M (600,ppb or 900,fg) was achieved for potassium ion in a 2,mM Tris-HCl buffer (pH,8.7) with a linear range of 2 orders of magnitude without any stacking. The proposed detection method avoids integrating the sensing electrodes directly within the separation channel and prevents any direct contact of the electrodes with the sample. The baseline signal can also be used for online monitoring of the electric field strength and electroosmosis mobility characterization in the separation channel. [source] Multifunctional FeCo/TiN Multilayer Thin Films with Combined Magnetic and Protective Properties,ADVANCED ENGINEERING MATERIALS, Issue 12 2009Christian Klever Abstract Coatings with thicknesses ranging from a few nanometer up to several micrometer produced by physical vapor deposition (PVD) processes have been established in engineering technologies since the early 1980s. In particular, magnetron sputtered wear resistance coatings are industrially established and capable to enhance tool lifetimes significantly. However, in cases where optical inspection of a coating in use is not possible, an intrinsic sensor function of the film would be beneficial. Therefore, the development of wear resistant coatings with an integrated sensor functionality based on the insertion of a magnetoelastic ferromagnetic phase is suggested. In combination with appropriate read-out electronics such a film system would be ready for online monitoring of the coatings' actual state (e.g., strain, temperature, volume loss). This paper focuses on the development of wear resistance coatings which simultaneously supply beneficial mechanical properties as well as ferromagnetic properties optimized for online non-contact read-out applications. Multilayer coatings obtained through alternate stacking of magnetron sputtered TiN and FeCo layers with a nominal total thickness of 1000,nm were produced as a model system meeting the above conditions. The bilayer period was varied down to 2.6,nm while the individual layer thickness ratio tTiN/tFeCo was determined by the deposition rates and maintained constant at a value of about 3/1. The films were vacuum annealed ex situ in a static magnetic field subsequent to the deposition. The constitution of the as-deposited and annealed coatings as well as their mechanical (nanohardness, Young's modulus) and magnetic properties (magnetization hysteresis, frequency-dependent permeability) are described. Finally, the suitability of the coatings for the use in remote-interrogable wear sensor applications is briefly discussed. [source] Polymer characterization by ultrasonic wave propagationADVANCES IN POLYMER TECHNOLOGY, Issue 2 2008Francesca Lionetto Abstract The propagation of low-intensity ultrasound in polymers, acting as a high-frequency dynamic mechanical deformation, can be successfully used to monitor changes in the modulus of polymers associated with glass transition, crystallization, cross-linking, and other chemical and physical phenomena related to changes in the viscoelastic behavior, such as gelation phenomena. The velocity of sound is related to the polymer storage modulus and density, whereas the absorption of ultrasonic waves is related to the energy dissipation in the material and, therefore, to the loss modulus. Accordingly, ultrasonic measurements have been used by several authors to monitor the evolution of the viscoelastic moduli of polymers as a function of time or temperature and, recently, become a characterization technique of its own right, generally known as ultrasonic dynamic mechanical analysis (UDMA). Often the technique is used in conjunction with rheological methods as a means of providing a better insight into the viscoelastic behavior of polymer systems. As yet UDMA is underutilized primarily because of the low operating temperatures (usually below 100,C) of commercially available ultrasonic transducers, and also due to the requirement of a coupling medium to ensure an efficient energy transfer mechanism between the transducer and the test material. Despite these limitations, this paper shows that the use of ultrasonics is potentially a powerful method for the characterization of polymers, particularly as a tool for online monitoring of events occurring during polymer processing and in the manufacture of polymer matrix composites. The aim of this paper is to review the progress made in recent years, highlighting the potential and reliability of UDMA for monitoring physical transitions in polymers such as glass transition, melting, crystallization, as well as physical changes taking place during curing of thermosetting resins. © 2009 Wiley Periodicals, Inc. Adv Polym Techn 27:63,73, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/adv.20124 [source] Towards a quantitative SERS approach , online monitoring of analytes in a microfluidic system with isotope-edited internal standardsJOURNAL OF BIOPHOTONICS, Issue 4 2009Anne März Abstract In this contribution a new approach for quantitative measurements using surface-enhanced Raman spectroscopy (SERS) is presented. Combining the application of isotope-edited internal standard with the advantages of the liquid,liquid segmented-flow-based approach for flow-through SERS detection seems to be a promising means for quantitative SERS analysis. For the investigations discussed here a newly designed flow cell, tested for ideal mixing efficiency on the basis of grayscale-value measurements, is implemented. Measurements with the heteroaromatics nicotine and pyridine using their respective deuterated isotopomers as internal standards show that the integration of an isotopically labeled internal standard in the used liquid,liquid two-phase segmented flow leads to reproducible and comparable SERS spectra independent from the used colloid. With the implementation of an internal standard into the microfluidic device the influence of the properties of the colloid on the SERS activity can be compensated. Thus, the problem of a poor batch-to-batch reproducibility of the needed nanoparticle solutions is solved. To the best of our knowledge these are the first measurements combining the above mentioned concepts in order to correct for differences in the enhancement behaviour of the respective colloid. (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Emulsion polymerization: From fundamental mechanisms to process developmentsJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 5 2004José M. Asua Abstract Emulsion polymers are "products by process" whose main properties are determined during polymerization. In this scenario of margins reduction, increasing competition, and public sensitivity to environmental issues, the challenge is to achieve an efficient production of high-quality materials in a consistent, safe, and environmentally friendly way. This highlight reviews the investigations carried out at The University of the Basque Country to develop a knowledge-based strategy to achieve these goals. First, the research in fundamental mechanisms is discussed. This includes studies in radical entry and exit, oil-soluble initiators, propagation-rate constants of acrylic monomers, processes involved in the formation of branched and crosslinked polymers, microstructure modification by postreaction operations, the formation of particle morphology, and reactive surfactants. The advanced mathematical models developed in the group are also reviewed. In the second part, the advances in process development (optimization, online monitoring and control, monomer removal, production of high-solids, low-viscosity latices, and process intensification) are presented. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 1025,1041, 2004 [source] ERP correlates of online monitoring of auditory feedback during vocalizationPSYCHOPHYSIOLOGY, Issue 6 2009Colin S. Hawco Abstract When speakers hear the fundamental frequency (F0) of their voice altered, they shift their F0 in the direction opposite the perturbation. The current study used ERPs to examine sensory processing of short feedback perturbations during an ongoing utterance. In one session, participants produced a vowel at an F0 of their own choosing. In another session, participants matched the F0 of a cue voice. An F0 perturbation of 0, 25, 50, 100, or 200 cents was introduced for 100 ms. A mismatch negativity (MMN) was observed. Differences between sessions were only found for 200-cent perturbations. Reduced compensation when speakers experienced the 200-cent perturbations suggests that this larger perturbation was perceived as externally generated. The presence of an MMN, and no earlier (N100) response suggests that the underlying sensory process used to identify and compensate for errors in mid-utterance may differ from feedback monitoring at utterance onset. [source] Viscosity models for New Zealand black liquor at low solids concentrationsASIA-PACIFIC JOURNAL OF CHEMICAL ENGINEERING, Issue 4 2010S.B. Alabi Abstract Availability of accurate models for prediction of the viscosity of black liquor (BL) from the chemical pulping of pine will facilitate its online monitoring and control and subsequently the optimisation of combustion in a recovery boiler. New Zealand (NZ) BL viscosity data are limited, and no predictive model is available. The viscosities of the NZ BL samples at solids concentrations (SCs) < 50% were obtained at temperature of 25,85 °C and shear rate up to ,2000 s,1. The samples showed Newtonian behaviour. Existing models from the literature and a binomial model developed in this work were used to fit the viscosity data as a function of SC and temperature. Accuracies of these models were examined for both the log-transformed and the untransformed viscosity data using coefficient of correlation (R) and maximum absolute relative error (MARE) (between the actual and predicted viscosities), respectively, as indices. Although the existing models fit NZ BL viscosity data well when they were log-transformed, they performed poorly when not transformed. Conversely, the new binomial model gave accurate predictions with both the log-transformed and untransformed viscosity data (R = 0.9997; MARE = 5.7%). It is concluded that at low SCs, the viscosity of Newtonian BL can be accurately predicted using the new binomial model. Copyright © 2010 Curtin University of Technology and John Wiley & Sons, Ltd. [source] Online assessment of biofilm development, sloughing and forced detachment in tube reactor by means of magnetic resonance microscopyBIOTECHNOLOGY & BIOENGINEERING, Issue 1 2010Michael Wagner Abstract Magnetic resonance microscopy (MRM) was successfully applied for non-invasive online monitoring of biofilm development, sloughing, and forced detachment. Biofilm cultivation was performed in a tube reactor directly placed in the MRM scanner. Based on the differences in relaxation time of free and bound protons, the distributed water signal was allocated to the bulk and the biofilm phase. The velocity of the flowing water in the tube reactor was measured in all three directions (x, y, and z) at spatial resolutions of 78,µm. From the velocity data, maps of flow gradients (shear rates) were derived. The experiments showed that a more compact biofilm structure is sloughed off in total with nearly no biomass left on the substratum. Continued biofilm cultivation resulted in filamentous biofilm structures, which did not show any sloughing. Experiments at higher Reynolds numbers were performed in order to force biofilm detachment. Continuous measuring of proton velocity and biomass was used to characterize the different stages of biofilm development. The measurements revealed that biofilms are able to resist extremely high local shear stress being raised up to factor of 20 compared to the mean local shear stress acting on the complete biofilm surface. The maximum local shear stress of single biofilm structures exposed to flow was found to be on average seven times higher compared to the mean local shear stress of the entire biofilm surface. MRM was able to visualize and quantify the development of biofilms and interaction of biofilms with the surrounding fluid at the meso-scale. It is suggested that detachment and sloughing depends on both internal and external structural parameters. Biotechnol. Bioeng. 2010;107: 172,181. © 2010 Wiley Periodicals, Inc. [source] Twenty-four well plate miniature bioreactor system as a scale-down model for cell culture process developmentBIOTECHNOLOGY & BIOENGINEERING, Issue 1 2009Aaron Chen Abstract Increasing the throughput and efficiency of cell culture process development has become increasingly important to rapidly screen and optimize cell culture media and process parameters. This study describes the application of a miniaturized bioreactor system as a scaled-down model for cell culture process development using a CHO cell line expressing a recombinant protein. The microbioreactor system (M24) provides non-invasive online monitoring and control capability for process parameters such as pH, dissolved oxygen (DO), and temperature at the individual well level. A systematic evaluation of the M24 for cell culture process applications was successfully completed. Several challenges were initially identified. These included uneven gas distribution in the wells due to system design and lot to lot variability, foaming issues caused by sparging required for active DO control, and pH control limitation under conditions of minimal dissolved CO2. A high degree of variability was found which was addressed by changes in the system design. The foaming issue was resolved by addition of anti-foam, reduction of sparge rate, and elimination of DO control. The pH control limitation was overcome by a single manual liquid base addition. Intra-well reproducibility, as indicated by measurements of process parameters, cell growth, metabolite profiles, protein titer, protein quality, and scale-equivalency between the M24 and 2 L bioreactor cultures were very good. This evaluation has shown feasibility of utilizing the M24 as a scale-down tool for cell culture application development under industrially relevant process conditions. Biotechnol. Bioeng. 2009;102: 148,160. © 2008 Wiley Periodicals, Inc. [source] Development of a Novel Membrane Aerated Hollow-Fiber MicrobioreactorBIOTECHNOLOGY PROGRESS, Issue 2 2008Louis Villain A new challenge in biotechnological processes is the development of flexible bioprocessing platforms, allowing strain selection, facilitating scale-up and integrating separation steps. Miniaturization of such a cultivation system allows parallel use and the saving of resources but makes the supply of oxygen to the cells difficult. In this work we present a membrane aerated hollow-fiber microbioreactor (HFMBR) which consists of an acrylic glass module equipped with two different types of membrane fibers. Fibers of polyethersulfone and polyvinyldifluoride were used for substrate and oxygen supply, respectively. Cultivation of E. coli as model organism and production of His-tagged GFP were carried out in the extracapillary space of the membrane aerated HFMBR and compared with cultivations in shaking flask which are commonly used for screening experiments. The measurement of the oxygen transfer capacity and the online monitoring of the dissolved oxygen during the cultivation were performed using a fiber optic oxygen sensor. Online measurement of the optical density was also integrated to the bioreactor. Due to efficient oxygen transfer, a better cell growth than in the shaking flask experiments was achieved, while no negative influence on the GFP productivity was observed in the membrane aerated bioreactor. Thus the feasibility of a future integrated downstreaming could also be demonstrated. [source] | ||||||||||||||||||||||