scholarly journals Aptamer-Based Detection of Ampicillin in Urine Samples

Antibiotics ◽  
2020 ◽  
Vol 9 (10) ◽  
pp. 655
Author(s):  
Matthew D. Simmons ◽  
Lisa M. Miller ◽  
Malin O. Sundström ◽  
Steven Johnson
Keyword(s):  
Health Care ◽  
General Population ◽  
Bacterial Resistance ◽  
Sample Volume ◽  
Small Sample ◽  
Urine Samples ◽  
Drug Resistant ◽  
Relevant Range ◽  
Small Sample Volume

The misuse of antibiotics in health care has led to increasing levels of drug resistant infections (DRI’s) occurring in the general population. Most technologies developed for the detection of DRI’s typically focus on phenotyping or genotyping bacterial resistance rather than on the underlying cause and spread of DRI’s; namely the misuse of antibiotics. An aptameric based assay has been developed for the monitoring of ampicillin in urine samples, for use in determining optimal antibiotic dosage and monitoring patient compliance with treatment. The fluorescently labelled aptamers were shown to perform optimally at pH 7, ideal for buffered clinical urine samples, with limits of detection as low as 20.6 nM, allowing for determination of ampicillin in urine in the clinically relevant range of concentrations (100 nM to 100 µM). As the assay requires incubation for only 1 h with a small sample volume, 50 to 150 µL, the test would fit within current healthcare pathways, simplifying the adoption of the technology.

scholarly journals Universal Stokes’s nanomechanical viscometer

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Komal Chaudhary ◽  
Pooja Munjal ◽  
Kamal P. Singh
Keyword(s):  
Electric Field ◽  
Real Time ◽  
Sample Volume ◽  
Capillary Waves ◽  
Small Sample ◽  
Medical Applications ◽  
Rapid Measurement ◽  
Single Lens ◽  
Universal Applicability ◽  
Small Sample Volume

AbstractAlthough, many conventional approaches have been used to measure viscosity of fluids, most methods do not allow non-contact, rapid measurements on small sample volume and have universal applicability to all fluids. Here, we demonstrate a simple yet universal viscometer, as proposed by Stokes more than a century ago, exploiting damping of capillary waves generated electrically and probed optically with sub-nanoscale precision. Using a low electric field local actuation of fluids we generate quasi-monochromatic propagating capillary waves and employ a pair of single-lens based compact interferometers to measure attenuation of capillary waves in real-time. Our setup allows rapid measurement of viscosity of a wide variety of polar, non-polar, transparent, opaque, thin or thick fluids having viscosity values varying over four orders of magnitude from $$10^{0}{-}10^{4}~\text{mPa} \, \text{s}$$ 10 0 - 10 4 mPa s . Furthermore, we discuss two additional damping mechanisms for nanomechanical capillary waves caused by bottom friction and top nano-layer appearing in micro-litre droplets. Such self-stabilized droplets when coupled with precision interferometers form interesting microscopic platform for picomechanical optofluidics for fundamental, industrial and medical applications.

scholarly journals Seven-Rod Dielectric Sensor for Determination of Soil Moisture in Small Volumes

Proceedings ◽  
2020 ◽  
Vol 15 (1) ◽  
pp. 49
Author(s):  
Justyna Szerement ◽  
Aleksandra Woszczyk ◽  
Agnieszka Szypłowska ◽  
Marcin Kafarski ◽  
Arkadiusz Lewandowski ◽  
...  
Keyword(s):  
Dielectric Permittivity ◽  
Sandy Loam ◽  
Sample Volume ◽  
Small Sample ◽  
Silt Loam ◽  
Frequency Range ◽  
Fem Simulations ◽  
Dielectric Sensor ◽  
Permittivity Spectrum

The paper presents the performance of a seven-rod dielectric probe for determination of soil dielectric permittivity using FEM simulations as well as FDR and TDR measurements. The volume of the sensitivity zone of the tested probe was assessed basing on the simulations and measurement in liquids. The probe was also tested in two soils, sandy loam and silt loam. The obtained results suggested that the seven-rod probe can be used to accurately measure the dielectric permittivity spectrum in a small sample volume of about 8 cm3 in a frequency range from 20 MHz to 200 MHz.

Rapid Determination of Sufentanil in Human Plasma by UHPLC–QqQ-MS-MS

2020 ◽  
Author(s):  
Marcin Zawadzki ◽  
Grzegorz Kowalski ◽  
Agnieszka Chłopaś-Konowałek ◽  
Marta Siczek ◽  
Małgorzata Sobieszczańska ◽  
...  
Keyword(s):  
Human Plasma ◽  
Lower Limit ◽  
Rapid Determination ◽  
Ultra Performance Liquid Chromatography ◽  
Sample Volume ◽  
Small Sample ◽  
Plasma Samples ◽  
Limit Of Quantification ◽  
Detection And Identification

Abstract This paper presents a rapid, sensitive and precise method developed and validated for the quantification of sufentanil in biological samples using ultra-performance liquid chromatography coupled with QqQ-MS-MS. Plasma samples were extracted with simple and fast liquid-liquid extraction (ethyl acetate, pH 9). Calibration curve showed linearity in the concentration range of 0.005–30 µg/L. The lower limit of quantification was 0.010 µg/L. The most important method features are low lower limit of quantification value, simple plasma extraction and small sample volume. This method is suitable not only for evaluation of the pharmacokinetics, toxicology, bioavailability and clinical pharmacology of sufentanil but also for the detection and identification of this compound in human plasma samples for forensic purposes.

New sandwich ELISA for human urinary N-acetyl-β-d-glucosaminidase isoenzyme B as a useful clinical test

1997 ◽  
Vol 43 (4) ◽  
pp. 569-574 ◽  
Author(s):  
Yoshito Numata ◽  
Atsushi Morita ◽  
Yoko Kosugi ◽  
Kazunori Shibata ◽  
Nozomu Takeuchi ◽  
...  
Keyword(s):  
Human Urine ◽  
Sandwich Elisa ◽  
Sample Volume ◽  
Mean Value ◽  
Cross Reactivity ◽  
Urine Samples ◽  
Clinical Test ◽  
The Mean ◽  
Dilution Curves

Abstract We have developed a new ELISA for quantifying N-acetyl-β-d-glucosaminidase (NAG) isoenzyme B in human urine after raising monoclonal antibodies against the isoenzyme from human placenta. Though the obtained antibodies reacted not only to isoenzyme B but also to A, we could detect isoenzyme B selectively by a two-step sandwich ELISA with a pair of selected antibodies at low pH in the first reaction. The detected limit was 0.5 μg/L for a sample volume of 25 μL. Within-run CVs ranged from 2.5% to 5.4% and between-run CVs ranged from 6.2% to 9.1%. Recoveries of NAG isoenzyme B added to each of three urine samples ranged from 91% to 114%. The dilution curves of urine samples showed good linearity. The cross-reactivity of NAG isoenzyme A was practically negligible (2–3%). The mean value for NAG isoenzyme B in spot urines from healthy adults was 2.9 μg/g creatinine. This ELISA method is rapid and precise enough for routine determination of NAG isoenzyme B in human urine.

scholarly journals Automated HPLC screening of newborns for sickle cell anemia and other hemoglobinopathies

1996 ◽  
Vol 42 (5) ◽  
pp. 704-710 ◽  
Author(s):  
J W Eastman ◽  
R Wong ◽  
C L Liao ◽  
D R Morales
Keyword(s):  
Quality Control ◽  
Detection Limit ◽  
Sickle Cell Anemia ◽  
Sample Volume ◽  
Small Sample ◽  
Peak Resolution ◽  
Automated Hplc ◽  
Hb S ◽  
Blood Spot ◽  
Small Sample Volume

Abstract Automated HPLC is used to test dried blood-spot specimens from newborns for hemoglobins (Hb) F, A, S, C, E, and D. We present the method and report on its performance determined during >4 years of testing 2.5 x 10(6) newborns. The method features automated derivation of presumptive phenotypes; quantitative quality control and proficiency testing; throughput of one specimen per minute; small sample volume; hemoglobin concentrations quantified with an interlaboratory CV of 14-18%; retention times with interlaboratory CV of <2% and matching, within +/- 0.03 min, of laboratories and reagent lots; control of peak resolution; 0.5% detection limit for Hb S and C, and 1.0% for Hb F, A, E, and D; few interferences; and negligible background and carryover. Shortcomings of the method are the absence of microplate barcode identification and the need for manually pipetting the sample eluate into the microplate.

scholarly journals Mechanical and Heterogeneous Properties of Coal and Rock Quantified and Mapped at the Microscale

2020 ◽  
Vol 10 (1) ◽  
pp. 342 ◽  
Author(s):  
Changlun Sun ◽  
Guichen Li ◽  
Suhui Zhang ◽  
Jiahui Xu ◽  
Houqiang Yang
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Convenient Method ◽  
Elastic Moduli ◽  
Averaging Method ◽  
Sample Volume ◽  
Small Sample ◽  
Mechanical Parameters ◽  
Experimental Technology ◽  
Small Sample Volume

Due to the impossibility of obtaining intact standard experimental samples, it is difficult to test the mechanical properties of soft and broken coal and rock obtained from deep coal mines. So, an advanced experimental technology based on a small sample volume, nanoindentation technology, was introduced and used to measure the mechanical parameters of them. By using the averaging method, the hardness of shale, mudstone and coal are 1191.90 MPa, 674.95 MPa and 424.30 MPa, respectively; their elastic moduli are 20.39 GPa, 11.72 GPa and 5.47 GPa; and their fracture toughness were 1.66 MPa·m0.5, 1.28 MPa·m0.5 and 0.77 MPa·m0.5. These three mechanical parameters were used to quantify and map the heterogeneous properties of coal and rock for convenience and accuracy. For example, the inter quartile range (IQR) of the hardness of shale, mudstone, and coal are 1502.10 MPa, 1016.20 MPa and 54.64 MPa, respectively, meaning that coal has the best homogeneity among them. Nanoindentation technology provides researchers with a convenient method to conduct mechanical experiments at the microscale.

Liquid chromatography in open tubes.

1984 ◽  
Vol 30 (9) ◽  
pp. 1473-1476 ◽  
Author(s):  
M P Maskarinec ◽  
M J Sepaniak ◽  
A T Balchunas ◽  
J D Vargo
Keyword(s):  
Liquid Chromatography ◽  
Clinical Analysis ◽  
Sample Volume ◽  
Small Sample ◽  
Separation Power ◽  
Wide Applicability ◽  
Further Development ◽  
High Separation ◽  
Detector Technology ◽  
Small Sample Volume

Abstract Liquid chromatography in open tubes is evaluated for applicability to clinical analysis. The principal advantages of this technique include high separation power, reduced solvent consumption, and small sample volume requirements. Technology for the production of columns as small as 8 micron (i.d.) is described. Preliminary results are encouraging and, with further development in column and detector technology, the technique should find wide applicability in clinical analysis.

Development of Micro Optical Diffusion Sensor Based on Laser Induced Dielectrophoresis

2009 ◽  
Author(s):  
Yoshihiro Taguchi ◽  
Koichi Itani ◽  
Akira Ebisui ◽  
Yuji Nagasaka
Keyword(s):  
Concentration Distribution ◽  
High Speed ◽  
High Efficiency ◽  
Sample Volume ◽  
Small Sample ◽  
Micro Electro Mechanical Systems ◽  
Measurement Principle ◽  
Sinusoidal Pattern ◽  
Chemical Fields ◽  
Small Sample Volume

Micro-electro mechanical systems (MEMS) biochips realizing high-speed and high-efficiency of reaction and analysis attract much attention in medical as well as chemical fields. Especially, the miniaturized devices enabling small sample volume, arrayed, and portable measurement may become a powerful tool for material analysis and process control. We have proposed a novel micro optical diffusion sensor (MODS) which enables small sample volume, highspeed and non-contact measurement of diffusion coefficient of liquid sample. MODS consists of a pair of transparent electrodes (Al-doped Zinc oxide: AZO), a photoconductive layer (amorphous silicon: a-Si:H), two MEMS mirrors and excitation and probing fibers for inducing and detecting concentration distribution. The initial concentration distribution of sample is created by an opto-dielectrophoretic (opto-DEP) manipulation along with a sinusoidal pattern of irradiated beam on a photoconductive layer. In the present paper, the measurement principle is proposed, and the preliminary experiment using a bench top apparatus is reported.

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