12 results on '"El-Ali J"'
Search Results
2. Microchip flow cytometer with integrated polymer optical elements for measurement of scattered light.
- Author
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Wang, Z., El-Ali, J., Perch-Nielsen, I.R., Mogensen, K.B., Snakenborg, D., Kutter, J.P., and Wolff, A.
- Published
- 2004
- Full Text
- View/download PDF
3. Integrated polymer waveguides for absorbance detection in chemical analysis systems.
- Author
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Mogensen, K.B., El-Ali, J., Wolff, A., and Kutter, J.P.
- Published
- 2003
- Full Text
- View/download PDF
4. Microfabricated DNA amplification device monolithically integrated with advanced sample pre-treatment.
- Author
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El-Ali, J., Perch-Nielsen, I.R., Poulsen, C.R., Jensen, M., Telleman, P., and Wolff, A.
- Published
- 2003
- Full Text
- View/download PDF
5. Patterns and predictors of oral antipsychotic prescribing in adult patients with schizophrenia.
- Author
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Vadiei N, El-Ali J, Delaune J, Wild C, and Liu YS
- Abstract
Background: Evidence increasingly suggests minimal differences in efficacy between oral antipsychotics for the pharmacologic treatment of schizophrenia. As a result, newer treatment guidelines avoid an algorithmic approach to antipsychotic selection and recommend treatment be determined on a case-by-case basis., Objective: To determine patterns and predictors of oral antipsychotic prescribing for adults diagnosed with schizophrenia., Methods: This is a retrospective, cross-sectional study using data from the National Ambulatory Medical Survey (NAMCS) from 2005 to 2016 and 2018. Treatment options were defined as a first-generation antipsychotic (FGA), second-generation antipsychotic (SGA), or no antipsychotic. Multivariable logistic regression analysis was conducted to identify predictors of antipsychotic treatment, adjusting for predisposing, enabling, and need factors., Results: The final study sample consisted of visits by 38,403 adults (unweighted n = 1932; age ≥ 18) diagnosed with schizophrenia in the United States. Risperidone, olanzapine, and quetiapine were the most prescribed antipsychotics. Patients ≥65 years old were half as likely to be prescribed an SGA versus no antipsychotic (OR 0.44, 95% CI [0.31, 0.61]). Patients with a higher number of chronic conditions also had lower odds of being prescribed an SGA or FGA versus no antipsychotic (OR 0.98 [0.97, 0.99]; OR [0.96 [0.96, 0.99]), while patients prescribed a higher number of medications had higher odds of being prescribed an SGA versus no antipsychotic (OR 1.2, 95% CI [1.1, 1.4])., Conclusions: Multiple factors were associated with prescribing an SGA or FGA versus no antipsychotic, but no factors were associated with prescribing an SGA versus FGA. Future studies are needed to determine the reasoning behind differences in antipsychotic prescribing., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2022 The Authors.)
- Published
- 2022
- Full Text
- View/download PDF
6. Cascaded free-flow isoelectric focusing for improved focusing speed and resolution.
- Author
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Albrecht JW, El-Ali J, and Jensen KF
- Subjects
- Biomarkers analysis, Electrophoresis, Polyacrylamide Gel, Equipment Design, Proteins analysis, Time Factors, Isoelectric Focusing instrumentation, Isoelectric Focusing standards
- Abstract
This work presents the first implementation of cascaded stages for a microfabricated free-flow isoelectric focusing (FF-IEF) device. Both analytical and computational models for IEF suggest device performance will be improved by utilizing multiple stages to reduce device residence time. These models are shown to be applicable by using focusing of small IEF markers as a demonstration. We also show focusing of fluorescently tagged proteins under different channel geometries, with the most efficient focusing occurring in the cascaded design, as predicted by theory. An additional aim of this work is to demonstrate the compatibility of cascaded FF-IEF with common bioanalytical tools. As an example, outlet fractions from cascaded FF-IEF were analyzed by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). Processing of whole cell lysate followed by immunoblotting for cell signaling markers demonstrates the reduction of albumin from samples, as well as the enrichment of apoptotic markers.
- Published
- 2007
- Full Text
- View/download PDF
7. Cells on chips.
- Author
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El-Ali J, Sorger PK, and Jensen KF
- Subjects
- Animals, Cell Extracts analysis, Cell Extracts chemistry, Cells, Immobilized metabolism, Drug Evaluation, Preclinical, Extracellular Matrix metabolism, Humans, Cell Culture Techniques instrumentation, Cell Culture Techniques methods, Cells, Immobilized cytology, Lab-On-A-Chip Devices, Microchip Analytical Procedures methods
- Abstract
Microsystems create new opportunities for the spatial and temporal control of cell growth and stimuli by combining surfaces that mimic complex biochemistries and geometries of the extracellular matrix with microfluidic channels that regulate transport of fluids and soluble factors. Further integration with bioanalytic microsystems results in multifunctional platforms for basic biological insights into cells and tissues, as well as for cell-based sensors with biochemical, biomedical and environmental functions. Highly integrated microdevices show great promise for basic biomedical and pharmaceutical research, and robust and portable point-of-care devices could be used in clinical settings, in both the developed and the developing world.
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- 2006
- Full Text
- View/download PDF
8. Flow-induced deformation of shallow microfluidic channels.
- Author
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Gervais T, El-Ali J, Günther A, and Jensen KF
- Subjects
- Computer Simulation, Microfluidics instrumentation, Microscopy, Confocal methods, Models, Chemical, Pressure, Dimethylpolysiloxanes chemistry, Microfluidics methods, Silicones chemistry
- Abstract
We study the elastic deformation of poly(dimethylsiloxane) (PDMS) microchannels under imposed flow rates and the effect of this deformation on the laminar flow profile and pressure distribution within the channels. Deformation is demonstrated to be an important consideration in low aspect ratio (height to width) channels and the effect becomes increasingly pronounced for very shallow channels. Bulging channels are imaged under varying flow conditions by confocal microscopy. The deformation is related to the pressure and is thus non-uniform throughout the channel, with tapering occurring along the stream-wise axis. The measured pressure drop is monitored as a function of the imposed flow rate. For a given pressure drop, the corresponding flow rate in a deforming channel is found to be several times higher than expected in a non-deforming channel. The experimental results are supported by scaling analysis and computational fluid dynamics simulations coupled to materials deformation models.
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- 2006
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9. Cell stimulus and lysis in a microfluidic device with segmented gas-liquid flow.
- Author
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El-Ali J, Gaudet S, Günther A, Sorger PK, and Jensen KF
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- Antibodies, Monoclonal pharmacology, Cell Line, Tumor, Cell Survival drug effects, Humans, Jurkat Cells drug effects, Lab-On-A-Chip Devices, Microchip Analytical Procedures methods, Mitogen-Activated Protein Kinases drug effects, Mitogen-Activated Protein Kinases physiology, Sensitivity and Specificity, Surface Properties, Temperature, Time Factors, Tumor Cells, Cultured, Microfluidic Analytical Techniques instrumentation, Microfluidic Analytical Techniques methods
- Abstract
We describe a microfluidic device with rapid stimulus and lysis of mammalian cells for resolving fast transient responses in cell signaling networks. The device uses segmented gas-liquid flow to enhance mixing and has integrated thermoelectric heaters and coolers to control the temperature during cell stimulus and lysis. Potential negative effects of segmented flow on cell responses are investigated in three different cell types, with no morphological changes and no activation of the cell stress-sensitive mitogen activated protein kinases observed. Jurkat E6-1 cells are stimulated in the device using alpha-CD3, and the resulting activations of ERK and JNK are presented for different time points. Stimulation of cells performed on chip results in pathway activation identical to that of conventionally treated cells under the same conditions.
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- 2005
- Full Text
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10. Measurements of scattered light on a microchip flow cytometer with integrated polymer based optical elements.
- Author
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Wang Z, El-Ali J, Engelund M, Gotsaed T, Perch-Nielsen IR, Mogensen KB, Snakenborg D, Kutter JP, and Wolff A
- Subjects
- Equipment Design, Flow Cytometry methods, Light, Photography instrumentation, Photography methods, Scattering, Radiation, Flow Cytometry instrumentation, Optics and Photonics instrumentation, Polymers chemistry
- Abstract
Flow cytometry is widely used for analyzing microparticles, such as cells and bacteria. In this paper, we report an innovative microsystem, in which several different optical elements (waveguides, lens and fiber-to-waveguide couplers) are integrated with microfluidic channels to form a complete microchip flow cytometer. All the optical elements, the microfluidic system, and the fiber-to-waveguide couplers were defined in one layer of polymer (SU-8, negative photoresist) by standard photolithography. With only a single mask procedure required, all the fabrication and packaging processes can be finished in one day. Polystyrene beads were measured in the microchip flow cytometer, and three signals (forward scattering, large angle scattering and extinction) were measured simultaneously for each bead. To our knowledge this is the first time forward scattered light and incident light extinction were measured in a microsystem using integrated optics. The microsystem can be applied for analyzing different kinds of particles and cells, and can easily be integrated with other microfluidic components.
- Published
- 2004
- Full Text
- View/download PDF
11. Removal of PCR inhibitors using dielectrophoresis as a selective filter in a microsystem.
- Author
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Perch-Nielsen IR, Bang DD, Poulsen CR, El-Ali J, and Wolff A
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- Animals, Cattle, Electrophoresis instrumentation, Hemoglobins isolation & purification, Hemoglobins pharmacology, Heparin isolation & purification, Heparin pharmacology, Microchemistry instrumentation, Microchemistry methods, Ribosomal Proteins genetics, Saccharomyces cerevisiae chemistry, Saccharomyces cerevisiae cytology, Saccharomyces cerevisiae genetics, Electrophoresis methods, Polymerase Chain Reaction methods
- Abstract
Diagnostic PCR has been used to analyse a wide range of biological materials. Conventional PCR consists of several steps such as sample preparation, template purification, and PCR amplification. PCR is often inhibited by contamination of DNA templates. To increase the sensitivity of the PCR, the removal of PCR inhibitors in sample preparation steps is essential and several methods have been published. The methods are either chemical or based on filtering. Conventional ways of filtering include mechanical filters or washing e.g. by centrifugation. Another way of filtering is the use of electric fields. It has been shown that a cell will experience a force when an inhomogeneous electric field is applied. The effect is called dielectrophoresis (DEP). The resulting force depends on the difference between the internal properties of the cell and the surrounding fluid. DEP has been applied to manipulate cells in many microstructures. In this study, we used DEP as a selective filter for holding cells in a microsystem while the PCR inhibitors were flushed out of the system. Haemoglobin and heparin - natural components of blood - were selected as PCR inhibitors, since the inhibitory effects of these components to PCR have been well documented. The usefulness of DEP in a microsystem to withhold baker's yeast (Saccharomyces cerevisiae) cells while the PCR inhibitors haemoglobin and heparin are removed will be presented and factors that influence the effect of DEP in the microsystem will be discussed. This is the first time dielectrophoresis has been used as a selective filter for removing PCR inhibitors in a microsystem.
- Published
- 2003
- Full Text
- View/download PDF
12. Integration of polymer waveguides for optical detection in microfabricated chemical analysis systems.
- Author
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Mogensen KB, El-Ali J, Wolff A, and Kutter JP
- Subjects
- Equipment Design, Miniaturization instrumentation, Miniaturization methods, Photography instrumentation, Photography methods, Reproducibility of Results, Rheology methods, Sensitivity and Specificity, Bromthymol Blue analysis, Optics and Photonics instrumentation, Photometry instrumentation, Photometry methods, Rheology instrumentation, Transducers
- Abstract
Multimode polymer waveguides and fiber-to-waveguide couplers have been integrated with microfluidic channels by use of a single-mask-step procedure, which ensured self-alignment between the optics and the fluidics and allowed a fabrication and packaging time of only one day. Three fabrication procedures for obtaining hermetically sealed channels were investigated, and the spectrally resolved propagation loss (400-900 nm) of the integrated waveguides was determined for all three procedures. Two chemical absorbance cells with optical path lengths of 100 and 1000 microm were furthermore fabricated and characterized in terms of coupling loss, sensitivity, and limit of detection for measurements of the dye bromothymol blue.
- Published
- 2003
- Full Text
- View/download PDF
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