Rapid Simultaneous Measurement Research Articles

High accuracy, high dynamic range optomechanical accelerometry enabled by dual comb spectroscopy

Cavity optomechanical sensors can offer exceptional sensitivity; however, interrogating the cavity motion with high accuracy and dynamic range has proven to be challenging. Here, we employ a dual optical frequency comb spectrometer to readout a microfabricated cavity optomechanical accelerometer, allowing for rapid simultaneous measurements of the cavity’s displacement, finesse, and coupling at accelerations up to 24 g (236 m/s2). With this approach, we have achieved a displacement sensitivity of 2 fm Hz−1/2, a measurement rate of 100 kHz, and a dynamic range of 7.6 × 105, which is the highest we are aware of for a microfabricated cavity optomechanical sensor. In addition, comparisons of our optomechanical sensor coupled directly to a commercial reference accelerometer show agreement at the 0.5% level, a value that is limited by the reference’s reported uncertainty. Furthermore, the methods described herein are not limited to accelerometry but rather can be readily applied to nearly any optomechanical sensor where the combination of high speed, dynamic range, and sensitivity is expected to be enabling.

Rapid Temperature-Dependent Rheological Measurements of Non-Newtonian Solutions Using a Machine-Learning Aided Microfluidic Rheometer.

Biofluids such as synovial fluid, blood plasma, and saliva contain several proteins which impart non-Newtonian properties to the biofluids. The concentration of such protein macromolecules in biofluids is regarded as an important biomarker for the diagnosis of several health conditions, including cardiovascular disorders, joint quality, and Alzheimer's. Existing technologies for the measurements of macromolecules in biofluids are limited; they require a long turnaround time, or require complex protocols, thus calling for alternative, more suitable, methodologies aimed at such measurements. According to the well-established relations for polymer solutions, the concentration of macromolecules in solutions can also be derived via measurement of rheological properties such as shear-viscosity and the longest relaxation time. We here introduce a microfluidic rheometer for rapid simultaneous measurement of shear viscosity and longest relaxation time of non-Newtonian solutions at different temperatures. At variance with previous technologies, our microfluidic rheometer provides a very short turnaround time of around 2 min or less thanks to the implementation of a machine-learning algorithm. We validated our platform on several aqueous solutions of poly(ethylene oxide). We also performed measurements on hyaluronic acid solutions in the clinical range for joint grade assessment. We observed monotonic behavior with the concentration for both rheological properties, thus speculating on their use as potential rheo-markers, i.e., rheological biomarkers, across several disease states.

Desorption electrospray ionization mass spectrometry imaging in discovery and development of novel therapies.

Desorption electrospray ionization mass spectrometry imaging (DESI-MSI) is one of the least specimen destructive ambient ionization mass spectrometry tissue imaging methods. It enables rapid simultaneous mapping, measurement, and identification of hundreds of molecules from an unmodified tissue sample. Over the years, since its first introduction as an imaging technique in 2005, DESI-MSI has been extensively developed as a tool for separating tissue regions of various histopathologic classes for diagnostic applications. Recently, DESI-MSI has also emerged as a versatile technique that enables drug discovery and can guide the efficient development of drug delivery systems. For example, it has been increasingly employed for uncovering unique patterns of in vivo drug distribution, the discovery of potentially treatable biochemical pathways, revealing novel druggable targets, predicting therapeutic sensitivity of diseased tissues, and identifying early tissue response to pharmacological treatment. These and other recent advances in implementing DESI-MSI as the tool for the development of novel therapies are highlighted in this review.

MEASUREMENT OF CORTISOL AND CORTISONE IN HUMAN SALIVA BY UPLC-MS/MS

Objective: To develop and validate a simple and rapid assay for simultaneous measurement of cortisol and cortisone in human saliva by ultra-performance liquid chromatography-tandem mass spectrometry. Methods: Chromatographic analysis was performed on an Atlantis dC18 column (2.1 x 100 mm, 3 µm) using a mobile phase consisting of acetonitrile and 2 mmol ammonium-acetate (50:50, v; v) that was delivered at a flow rate of 0.3 ml/min. The eluents were monitored using electrospray ionization in the positive ion mode set at transition set of mass-to-charge (m/z): 363.11 → 121.00, 361.18 → 163.11, and 367.19 → 121.24 for cortisol, cortisone and internal standard (IS), respectively the method was validated for linearity, accuracy, precision, and recovery, according to international guidelines. Results: The retention times of cortisol, cortisone and internal were about 1.38, 1.43 and 1.38 min, respectively. Cortisol level and cortisone level relationship to the ratio of their respective peak-area to IS’s peak-area was linear (range of 0.5-100 ng/ml). Coefficients of variation and inaccuracy were, ≤9.9% and-0.3 to 6.9 for cortisol and ≤8.4 and-1.5 to 4.8 for cortisone, respectively. Extraction recoveries for cortisol, cortisone, and the IS were 90%, 94%, and 98%, respectively. Cortisol and cortisone stability was evaluated in processed saliva samples (stored at room temperature for 24 h) and unprocessed saliva samples (stored at room temperature for 24 h or at-20 °C for 10 w) and after 3 freeze-thaw cycles was ≥ 86%. Conclusion: The proposed method is simple, precise, and accurate for the rapid simultaneous measurement of cortisol and cortisone levels in saliva. The assay was successfully applied to determine levels of cortisol and cortisone in human saliva samples obtained from healthy volunteers.

MR Fingerprinting of Adult Brain Tumors: Initial Experience.

MR fingerprinting allows rapid simultaneous quantification of T1 and T2 relaxation times. This study assessed the utility of MR fingerprinting in differentiating common types of adult intra-axial brain tumors. MR fingerprinting acquisition was performed in 31 patients with untreated intra-axial brain tumors: 17 glioblastomas, 6 World Health Organization grade II lower grade gliomas, and 8 metastases. T1, T2 of the solid tumor, immediate peritumoral white matter, and contralateral white matter were summarized within each ROI. Statistical comparisons on mean, SD, skewness, and kurtosis were performed by using the univariate Wilcoxon rank sum test across various tumor types. Bonferroni correction was used to correct for multiple-comparison testing. Multivariable logistic regression analysis was performed for discrimination between glioblastomas and metastases, and area under the receiver operator curve was calculated. Mean T2 values could differentiate solid tumor regions of lower grade gliomas from metastases (mean, 172 ± 53 ms, and 105 ± 27 ms, respectively; P = .004, significant after Bonferroni correction). The mean T1 of peritumoral white matter surrounding lower grade gliomas differed from peritumoral white matter around glioblastomas (mean, 1066 ± 218 ms, and 1578 ± 331 ms, respectively; P = .004, significant after Bonferroni correction). Logistic regression analysis revealed that the mean T2 of solid tumor offered the best separation between glioblastomas and metastases with an area under the curve of 0.86 (95% CI, 0.69-1.00; P < .0001). MR fingerprinting allows rapid simultaneous T1 and T2 measurement in brain tumors and surrounding tissues. MR fingerprinting-based relaxometry can identify quantitative differences between solid tumor regions of lower grade gliomas and metastases and between peritumoral regions of glioblastomas and lower grade gliomas.

An enhanced technique for automated determination of 15N signatures of N2, (N2+N2O) and N2O in gas samples

An enhanced analytical approach for analyzing gaseous products from (15)N-enriched pools has been developed. This technique can be used to quantify nitrous oxide (N2O) and dinitrogen (N2) fluxes from denitrification. It can also help in distinguishing different N2- and N2O-forming processes, such as denitrification, nitrification, anaerobic ammonium oxidation or co-denitrification. The measurement instrumentation was based on a commercially available automatic preparation system allowing collection and separation of gaseous samples. The sample transfer paths, valves, liquid nitrogen traps, gas chromatography column and open split of the original system were modified. A reduction oven (Cu) was added in order to eliminate oxygen and measure N2O-N as N2. Gases leaving the separation system entered an isotope ratio mass spectrometer where masses (28)N2, (29)N2 and (30)N2 were measured. The enhanced technique enabled rapid simultaneous measurement of stable isotope ratios (29)N2/(28)N2 and (30)N2/(28)N2 originating from dinitrogen alone (N2) and from the sum of the denitrification products (N2 +N2O) as well as the determination of (15)N enrichment in N2O. The (15)N fraction in the N pool undergoing N2 and N2O production ((15)X(N)) and the contribution of N2 and N2O originating from this pool (d) were determined with satisfactory accuracy of better than 3.3% and 2.9%, respectively. The precision and accuracy of this method were comparable with or better than previously reported for similar measurements. The proposed method allows for the analysis of all quantities within one run, thus reducing the measurement and sample preparation time as well as increasing the reliability of the results.

On the urinary disposition of phenformin and 4-hydroxy-phenformin and their rapid simultaneous measurement.

Journal Article On the urinary disposition of phenformin and 4-hydroxy-phenformin and their rapid simultaneous measurement Get access N S Oates, N S Oates Department of Biochemical and Experimental Pharmacology, St Mary's Hospital Medical School, London, W2 1PG, UK Search for other works by this author on: Oxford Academic Google Scholar R R Shah, R R Shah Department of Biochemical and Experimental Pharmacology, St Mary's Hospital Medical School, London, W2 1PG, UK Search for other works by this author on: Oxford Academic Google Scholar J R Idle, J R Idle Department of Biochemical and Experimental Pharmacology, St Mary's Hospital Medical School, London, W2 1PG, UK Correspondence: Department of Biochemical and Experimental Pharmacology, St Mary's Hospital Medical School, London, W2 1PG, U.K Search for other works by this author on: Oxford Academic Google Scholar R L Smith R L Smith Department of Biochemical and Experimental Pharmacology, St Mary's Hospital Medical School, London, W2 1PG, UK Search for other works by this author on: Oxford Academic Google Scholar Journal of Pharmacy and Pharmacology, Volume 32, Issue 1, September 1980, Pages 731–732, https://doi.org/10.1111/j.2042-7158.1980.tb13056.x Published: 12 April 2011 Article history Received: 07 May 1980 Published: 12 April 2011

Rapid, simple and simultaneous measurement of kynurenine and tryptophan in plasma by column switching-HPLC method

Abstract We established a highly reproducible, simple and rapid simultaneous measurement method in which blood plasma can be directly injected into high-performance liquid chromatography (HPLC) without conducting conventional extraction of kynurenine (Kyn) and tryptophan (Trp) from blood plasma. In this method, Kyn and Trp were first separated from proteins present in blood plasma using a pre-column. Then, by column-switching, the separated Kyn and Trp were automatically injected into a separation column. The recoveries of Kyn and Trp determined in blood plasma by this method were 100.0 ± 0.9 and 100.0 ± 1.4%, respectively.

Observation of a chaotic multioscillatory metabolic attractor by real‐time monitoring of a yeast continuous culture

We monitored a continuous culture of the yeast Saccharomyces cerevisiae by membrane-inlet mass spectrometry. This technique allows very rapid simultaneous measurements (one point every 12 s) of several dissolved gases. During our experiment, the culture exhibited a multioscillatory mode in which the dissolved oxygen and carbon dioxide records displayed periodicities of 13 h, 36 min and 4 min. The 36- and 4-min modes were not visible at all times, but returned at regular intervals during the 13-h cycle. The 4-min mode, which has not previously been described in continuous culture, can also be seen when the culture displays simpler oscillatory behavior. The data can be used to visualize a metabolic attractor of this system, i.e. the set of dissolved gas concentrations which are consistent with the multioscillatory state. Computation of the leading Lyapunov exponent reveals the dynamics on this attractor to be chaotic.

Rapid simultaneous measurement of multiple cytokines in childhood oncology patients with febrile neutropenia: increased interleukin (IL)‐8 or IL‐5 correlates with culture‐positive infection

Hodge, G. ; Osborn, M. ; Hodge, S. ; Nairn, J. ; Tapp, H. ; Kirby, M. ; Sepulveda, H. ; Morgan, E. ; Revesz, T. ; Zola, H.

Analysis of neuroactive amino acids from microdialysate samples by fluorescence detection using a modification of the 6-aminoquinolyl-N-hydroxysuccinimidyl carbamate method

A sensitive and rapid reversed-phase high-performance liquid chromatographic method using pre-column derivatization with 6-aminoquinolyl-N-hydroxysuccinimidyl carbamate (AQC) and fluorescence detection is reported. By directly derivatizing microdialysate samples with AQC, an automatic and rapid simultaneous measurement of aspartate, serine, glutamate, glycine and histidine was developed. Excellent linearity (r2 > or = 0.998) was achieved for the standard mixture used for the validation experiments. Within-day and between-day precision was less than 6.2%, and the accuracy ranged from 95 to 105.2% in standards. This method is suitable for single run analysis of a high number of small volume microdialysate samples from rat hippocampus. Amino acids from microdialysate samples were quantified with RSD for reproducibility below 2%, and at approximately 0.1% for retention time.

Microchip Separation and Electrochemical Detection of Amino Acids and Peptides Following Precolumn Derivatization with Naphthalene‐2,3‐dicarboxyaldehyde

AbstractAn integrated microfluidic device is used to derivatize, separate, and amperometrically detect amino acids and peptides in the presence of naphthalene‐2,3‐dicarboxyaldehyde (NDA). The integrated system offers a rapid (4 min) simultaneous measurements of 5 amino acids (Arg, Lys, Gly, Cys, PhenA) down to the 3.2 μM level in connection to a precolumn reaction chamber, an electrophoretic separation channel, and an end‐column thick‐film carbon‐electrode detector. The effect of the separation voltage, detection potential, reagent concentration, and other variables on the response is examined. Calibration and precision experiments indicate a linear and reproducible response. Applicability for the separation and detection of small peptides is demonstrated. Such on‐chip generation of electroactive products offers great promise for detecting other nonelectroactive analytes.

Non-aqueous capillary electrophoretic separation and detection of 6H-pyrimido[2,1-a]isoindoles

A non-aqueous capillary electrophoresis system for separating and detecting antidepressant drugs based on the coupling of capillary electrophoresis separation in acetonitrile and UV detection is described. The system offers a rapid simultaneous measurement in less than 12 min for six priority pyrimidoisoindoles. These antidepressants were detected down to the 2.5×10–6–4.2×10–6 mol/L level, with linearity up to the 1×10–3 mol/L level examined. A highly stable response was observed for repetitive injections (R.S.D. < 2.6%, n = 12). The influence of pH and content of acetonitrile upon the electrophoretic mobilities was also studied.

Rapid Simultaneous Mapping of T2 and T2* by Multiple Acquisition of Spin and Gradient Echoes Using Interleaved Echo Planar Imaging (MASAGE-IEPI)

A new MRI sequence for the rapid simultaneous measurement of T2 and T2* is presented. The technique uses the multiple acquisition of spin and gradient echoes with interleaved echo planar imaging (MASAGE-IEPI). IEPI data sets are sampled during and between a pair of short and long echo time spin echoes, allowing the reconstruction of a set of images with different combinations of T2 and T2* weighting and the calculation of T2 and T2* maps. In the context of neuroimaging, these maps can provide information on cerebral hemodynamics and oxygenation status, either via the deoxyhemoglobin-based BOLD signal or by the effect of exogenous paramagnetic contrast agents. MASAGE-IEPI benefits from the inherent advantages of the IEPI approach, i.e., high time resolution and minimal image distortion, and also has good time efficiency due to the acquisition of multiple image data sets following each excitation pulse. The accuracy of the sequence for the measurement of T2 and T2* is verified on phantoms, and the technique is applied to monitor changing hemodynamics in the rat brain during episodes of hypoxia. Data for the generation of maps of T2 and T2* are acquired with a time resolution of 12 s to accurately define the rapidly changing time course. As increasing emphasis is placed on the role of T2 and T2* in the direct measurement of physiological parameters such as cerebral metabolic rate of oxygen consumption and blood vessel sizes, MASAGE-IEPI offers an efficient method for the measurement of these two important MRI parameters.

Micromachined separation chips with a precolumn reactor and end-column electrochemical detector.

Glass microchips, integrating chemical derivatization reactions, electrophoretic separations, and amperometric detection, have been developed. The performance of the new integrated microfabricated devices is demonstrated for rapid on-chip measurements of amino acids utilizing precolumn reactions of amino acids with o-phthaldialdehyde/2-mercaptoethanol to generate electroactive derivatives that are separated electrophoretically and detected at the end-column electrochemical detector. The influence of the sample/reagent mixing ratio, reagent concentrations, driving voltage, detection potential, and other variables is explored. The integrated microsystem offers a rapid (6 min) simultaneous measurements of eight amino acids, down to approximately 2.5 x 10(-6) M (5 fmol) level, with linearity up to the 2 x 10(-4) M level examined, and good reproducibility (RSD = 2.2-2.7%). A step of the driving voltage is used for decreasing the migration time of late-eluting components and reducing the overall analysis time. The integrated microfabricated device expands the scope of on-chip electrochemical detection to nonelectroactive analytes and holds promise of being a powerful analytical tool.

Capillary electrophoresis microchips with thick-film amperometric detectors: separation and detection of phenolic compounds

A miniaturized analytical system for separating and detecting toxic phenolic compounds, based on the coupling of a micromachined capillary electrophoresis (CE) chip with a thick-film amperometric detector is described. The integrated microsystem offers a rapid (4 min) simultaneous measurement of seven priority chlorophenolic pollutants. Such compounds could be detected down to the 1×10 −6–2×10 −6 M level, with linearity up to the 2×10 −4 M level examined. The highly stable response observed for repetitive injections (R.S.D.=3.7%, n=20) reflects the negligible surface passivation due to the injection of extremely small sample volumes. Additional phenols were separated and detected upon raising the pH of the running buffer from 8.0 to 10.5. Applicability to river water samples is demonstrated. While the concept of miniaturized separation/detection systems is presented within the framework of phenolic contaminants, such devices should be attractive for field monitoring of other classes of priority contaminants. The development of fast-responding miniaturized systems with negligible waste production holds particular promise for meeting the requirements of field ‘Green Analytical Chemistry’.

Method and a simple apparatus for rapid simultaneous measurement of resonance frequency and Q factor of a quartz crystal

The quartz crystal microbalance is finding many novel uses beyond its traditional utility as a thin film deposition controller. In many situations where the quartz crystal is immersed in a viscous fluid, it is desirable to measure the crystal’s Q factor in addition to its resonance frequency. Here, we describe a simple method for simultaneous measurement of the resonance frequency, the quality factor, and the activity or relative amplitude of oscillation of a quartz crystal in vacuum and in gaseous environment. The hardware, comprising of a synthesized sine wave generator and a phase detector, passively interrogates the crystal to determine its resonance frequency and activity. The passive measurement system can detect a resonance even when the crystal is heavily damped. Representative measurement results for an AT-cut quartz crystal in a number of gases at various pressures are presented. The methodology described here may be readily applied to quartz crystals immersed in a liquid.

Rapid simultaneous measurement of nucleotides, nucleosides and bases in tissues by capillary electrophoresis.

Capillary electrophoresis (CE) is now one of the most efficient separation techniques. It has been rapidly developed since Jorgenson et al.1 used small diameter capillaries for the separation of ions in an electrical field. One of the greatest advantages of CE is the use of small sample amounts — from some few nl of sample to the cytosolic fluid of single cells2. These small sample volumes make it possible to solve a number of biological and clinical problems, where the amount of biological material is limited.KeywordsUric AcidCapillary ElectrophoresisCapillary Zone ElectrophoresisInosine MonophosphateMicellar Electrokinetic Capillary ChromatographyThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

Very rapid simultaneous measurement of nuclear magnetic resonance spin-lattice relaxation time and spin-spin relaxation time

A new method for measuring the spin-lattice relaxation time, T 1, and spin-spin relaxation time, T 2 is presented. It is based on a combination of two established pulse sequences. A fast-inversion-recovery sequence consisting of a fixed or variable wait, a 180° pulse, and a variable recovery time is employed. Then a Carr-Purcell-Meiboom-Gill (CPMG) sequence of echoes is integrated. At the end of this sequence the total nuclear magnetization is zero, providing an initial condition for the next measurement cycle. The CPMG sequence is an efficient means of signal accumulation for fast inversion recovery and simultaneously provides a measurement of T 2. The new system is faster than the best previously described means of measuring T 1 by a factor of T 2 T 2∗ . A phase-alternated pulse sequence that suppresses the baseline errors of the new measurement scheme is also introduced.

Use of simultaneous analysis of gas-exchange and chlorophyll fluorescence quenching for analysing the effects of water stress on photosynthesis in apple leaves

A convenient system for the rapid simultaneous measurement of both chlorophyll fluorescence quenching using a modulated light system, and of CO2, and water vapour exchange by leaves is described. The system was used in a study of the effects of water deficits on the photosynthesis by apple leaves (Malus x domestica Borkh.). Apple leaves were found to have low values of steady-state variable fluorescence, and the existence of significant fluorescence with open traps (Fo) quenching necessitated the measurement and use of a corrected Fo in the calculation of quenching components. Long-term water stress had a marked effect on both gas-exchange and chlorophyll fluorescence quenching. Non-photochemical quenching (qn) in particular was increased in water-stressed leaves, and it was particularly sensitive to incident radiation in such leaves. In contrast, rapid dehydration only affected gas exchange. Relaxation of qn quenching in the dark was slow, taking approximately 10 min for a 50% recovery, in well-watered and in draughted plants, and whether or not the plants had been exposed to high light.