scholarly journals MÉTODOS DE INJEÇÃO DA AMOSTRA EM MICROSSISTEMAS ELETROFORÉTICOS

Química Nova ◽  
2021 ◽  
Author(s):  
Kemilly Pinheiro ◽  
Kariolanda Rezende ◽  
Wendell Coltro
Keyword(s):  
Chemical Analysis ◽  
Low Cost ◽  
Sample Volume ◽  
Alternative Methods ◽  
Separation Channel ◽  
Acupuncture Needle ◽  
Sample Injection ◽  
Injection Mode ◽  
Injection Methods ◽  
Sample Amount

SAMPLE INJECTION METHODS IN ELECTROPHORETIC MICROSYSTEMS. Electrophoresis is by far the most popular separation method implemented in microscale, most probably due to its instrumental simplicity, low cost and portability. Due to the increasing use of miniaturized electrophoretic systems, the study of fundamental aspects can improve the development of methodologies for several applications. One of the major challenges related to electrophoresis chips refers to the sample injection mode, in this way, this study presents a review on sample injection methods for microchip electrophoresis covering electrokinetic and hydrodynamic approaches, describing theoretic and instrumental aspects. Since the sample volume affects the analytical performance, the precise and reproducible control of the sample amount to be introduced into the separation channel is highly desirable to ensure reliable chemical analysis. Electrokinetic modes based on floating, pinched and gated protocols are presented and discussed providing an overview about the electrokinetic control of the sample through three methodologies. In the same way, hydrodynamic techniques including the use of microfabricated valves and pumps, syringe pumps, electronic micropipettes, rubber suction bulb and acupuncture needle are approached, thus expanding the view of hydrodynamic injectors based on classical and alternative methods.

ALGOMA AR225

Alloy Digest ◽  
2003 ◽  
Vol 52 (12) ◽  
Keyword(s):  
Carbon Steel ◽  
Chemical Analysis ◽  
Physical Properties ◽  
Carbon Content ◽  
Brinell Hardness ◽  
Low Cost ◽  
Heat Treating ◽  
Rolled Plate ◽  
High Carbon ◽  
High Carbon Content

Abstract Algoma AR225 is a carbon steel developed primarily to supply a low-cost material for high-abrasion applications. It is furnished in the form of as-rolled plate with a relatively high carbon content (0.35-0.45%). AR-225 is sold on the basis of chemical analysis only; the number 225 signifies the approximate Brinell hardness. On thicknesses one-half inch and over, this Brinell value may be lower than 225 because of higher finishing temperatures. This datasheet provides information on composition, physical properties, hardness, and elasticity. It also includes information on forming, heat treating, machining, and joining. Filing Code: CS-138. Producer or source: Algoma Steel Corporation Ltd.

scholarly journals Demonstration of a Label-Free and Low-Cost Optical Cavity-Based Biosensor Using Streptavidin and C-Reactive Protein

Biosensors ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 4
Author(s):  
Donggee Rho ◽  
Seunghyun Kim
Keyword(s):  
Limit Of Detection ◽  
Point Of Care ◽  
Low Cost ◽  
Optical Cavity ◽  
Sample Volume ◽  
Small Sample ◽  
Label Free ◽  
C Reactive Protein ◽  
Reactive Protein ◽  
Cavity Structure

An optical cavity-based biosensor (OCB) has been developed for point-of-care (POC) applications. This label-free biosensor employs low-cost components and simple fabrication processes to lower the overall cost while achieving high sensitivity using a differential detection method. To experimentally demonstrate its limit of detection (LOD), we conducted biosensing experiments with streptavidin and C-reactive protein (CRP). The optical cavity structure was optimized further for better sensitivity and easier fluid control. We utilized the polymer swelling property to fine-tune the optical cavity width, which significantly improved the success rate to produce measurable samples. Four different concentrations of streptavidin were tested in triplicate, and the LOD of the OCB was determined to be 1.35 nM. The OCB also successfully detected three different concentrations of human CRP using biotinylated CRP antibody. The LOD for CRP detection was 377 pM. All measurements were done using a small sample volume of 15 µL within 30 min. By reducing the sensing area, improving the functionalization and passivation processes, and increasing the sample volume, the LOD of the OCB are estimated to be reduced further to the femto-molar range. Overall, the demonstrated capability of the OCB in the present work shows great potential to be used as a promising POC biosensor.

The Effect of Air Injection Method on the Airlift Pump Performance

2012 ◽  
Vol 134 (11) ◽  
Author(s):  
Dong Hu ◽  
Chuan-Lin Tang ◽  
Shu-Peng Cai ◽  
Feng-Hua Zhang
Keyword(s):  
Flow Rate ◽  
Volume Flow Rate ◽  
Low Cost ◽  
Air Injection ◽  
Water Volume ◽  
Pump Design ◽  
Pump Performance ◽  
Dimensionless Equation ◽  
Measurement Results ◽  
Injection Methods

With simple structure, excellent reliability, low cost, no restriction at depth of water, and easy control and operation, airlift pumps have special advantage in borehole hydraulic jet mining, river dredging and deep sea mining. To clarify the mechanism and process of action of air injection methods on air lift performance, and to enhance lifting capacity, the pump performance of a small airlift system in transporting river sands is investigated experimentally in the present study. The results are as the follows. The influences of air exit ports on water volume flow rate, mass flow rate of solids and lifting efficiency are studied and found to be very low when the number of air exit ports exceeds 3. The pump design show best pumping capability for water and solids at higher air flow rates, but the lifting efficiency is then very low. In addition, a dimensionless equation which describes the flows in the pipe is presented based on the Bernoulli equation, and compared with measurement results in the dimensionless form, which are nearly in good agreement with each other for all the arrangements of air exit ports and are basically contained within ±18% of the theoretical curve. The results are important for understanding the mechanism of airlift pumps and enriching multiphase flow theory.

Urinalysis

Nursing OSCEs ◽  
2012 ◽  
Author(s):  
Jane Lovegrove
Keyword(s):  
Chemical Analysis ◽  
Low Cost ◽  
Microscopic Investigation ◽  
Accurate Information ◽  
Clinical Settings ◽  
Acute Care Setting ◽  
Urethral Meatus ◽  
Naked Eye ◽  
Nurse Students ◽  
Diagnostic Reagent

Urinalysis simply means analysis of urine. It is an easily performed investigation that can detect a wide variety of abnormalities within a few minutes at low cost. Urinalysis is an investigation which all nurses should be competent to perform and is identified by the NMC (2007) as being an example of an essential skill nurse students should be competent to perform before entering their branch programme. Urinalysis may be performed in a wide variety of clinical settings. It should be performed on every patient entering the acute care setting. Additionally, the National Confidential Enquiry into Patient Outcome and Death (NCEPOD (2009), stresses the need for urinalysis to be performed on all emergency admissions to an acute hospital. It may also be performed in outpatient and general practice clinics, and community areas. To obtain the most accurate information from the test, students need to know how to obtain and assess a sample of urine and be aware of factors that may influence the reliability of the investigation. Urine may be tested in three different ways. ● Macroscopic urinalysis, ● Microscopic urinalysis, ● Chemical analysis. Macroscopic and chemical analysis are the investigations performed in the clinical setting which may be tested by OSCE. Microscopic investigation requires samples to be sent to a laboratory. Macroscopic analysis is the analysis of the urine by the naked eye. Chemical analysis may be performed by use of a plastic diagnostic reagent strip or ‘dipstick’ which contains small pads of chemicals which react to substances that may be found in urine. For purposes of testing urine at random, clients are asked to urinate into a clean but not sterile dry container with no precautions regarding contamination. In females in particular this may result in samples being contaminated by vaginal fluids, such as blood or mucus. Due to the risk of contamination a mid-stream specimen of urine may be required if an abnormality is found in a random sample. A mid-stream specimen requires cleaning of the external urethral meatus prior to urination, passing the first half of the bladder contents into the lavatory, and passing the second part of the urine flow into a sterile container.

scholarly journals Diazonium-Modified Screen-Printed Electrodes for Immunosensing Growth Hormone in Blood Samples

Biosensors ◽  
2019 ◽  
Vol 9 (3) ◽  
pp. 88 ◽  
Author(s):  
Nan Li ◽  
Ari M. Chow ◽  
Hashwin V. S. Ganesh ◽  
Melanie Ratnam ◽  
Ian R. Brown ◽  
...  
Keyword(s):  
Growth Hormone ◽  
Photoelectron Spectroscopy ◽  
Electrochemical Impedance ◽  
Low Cost ◽  
High Sensitivity ◽  
Sample Volume ◽  
Screening Methods ◽  
Serum Samples ◽  
Potential Applicability ◽  
Screen Printed

Altered growth hormone (GH) levels represent a major global health challenge that would benefit from advances in screening methods that are rapid and low cost. Here, we present a miniaturized immunosensor using disposable screen-printed carbon electrodes (SPCEs) for the detection of GH with high sensitivity. The diazonium-based linker layer was electrochemically deposited onto SPCE surfaces, and subsequently activated using covalent agents to immobilize monoclonal anti-GH antibodies as the sensing layer. The surface modifications were monitored using contact angle measurements and X-ray photoelectron spectroscopy (XPS). The dissociation constant, Kd, of the anti-GH antibodies was also determined as 1.44 (±0.15) using surface plasmon resonance (SPR). The immunosensor was able to detect GH in the picomolar range using a 20 µL sample volume in connection with electrochemical impedance spectroscopy (EIS). The selectivity of the SPCE-based immunosensors was also challenged with whole blood and serum samples collected at various development stages of rats, demonstrating the potential applicability for detection in biological samples. Our results demonstrated that SPCEs provided the development of low-cost and single-use electrochemical immunosensors in comparison with glassy carbon electrode (GCE)-based ones.

scholarly journals Thermal dewetting tunes surface enhanced resonance Raman scattering (SERRS) performance

RSC Advances ◽  
2018 ◽  
Vol 8 (51) ◽  
pp. 29062-29070 ◽  
Author(s):  
Sonia Andrikaki ◽  
Katerina Govatsi ◽  
Spyros N. Yannopoulos ◽  
George A. Voyiatzis ◽  
Konstantinos S. Andrikopoulos
Keyword(s):  
Chemical Analysis ◽  
Raman Scattering ◽  
Low Cost ◽  
Resonance Raman ◽  
Metallic Films ◽  
Resonance Raman Scattering ◽  
Sers Substrates ◽  
Surface Enhanced

Simple, reproducible and low-cost SERS substrates for ultra-sensitive chemical analysis/quantification offered by thermal dewetting of thin metallic films.

scholarly journals Chemical and microstructural analyses for heavy metals removal from water media by ceramic membrane filtration

2016 ◽  
Vol 75 (2) ◽  
pp. 439-450 ◽  
Author(s):  
Asmaa Ali ◽  
Abdelkader Ahmed ◽  
Ali Gad
Keyword(s):  
Heavy Metals ◽  
Chemical Analysis ◽  
Membrane Filtration ◽  
Ceramic Membrane ◽  
Low Cost ◽  
Ceramic Membranes ◽  
Filtration Process ◽  
X Ray ◽  
Before And After ◽  
Water Media

This study aims to investigate the ability of low cost ceramic membrane filtration in removing three common heavy metals namely; Pb2+, Cu2+, and Cd2+ from water media. The work includes manufacturing ceramic membranes with dimensions of 15 by 15 cm and 2 cm thickness. The membranes were made from low cost materials of local clay mixed with different sawdust percentages of 0.5%, 2.0%, and 5.0%. The used clay was characterized by X-ray diffraction (XRD) and X-ray fluorescence analysis. Aqueous solutions of heavy metals were prepared in the laboratory and filtered through the ceramic membranes. The influence of the main parameters such as pH, initial driving pressure head, and concentration of heavy metals on their removal efficiency by ceramic membranes was investigated. Water samples were collected before and after the filtration process and their heavy metal concentrations were determined by chemical analysis. Moreover, a microstructural analysis using scanning electronic microscope (SEM) was performed on ceramic membranes before and after the filtration process. The chemical analysis results showed high removal efficiency up to 99% for the concerned heavy metals. SEM images approved these results by showing adsorbed metal ions on sides of the internal pores of the ceramic membranes.

Microfluidic Pumping With Optically Induced Actuation of a Carbon Nanotube Membrane

2010 ◽  
Author(s):  
Joseph D. Duff ◽  
Stuart J. Williams ◽  
Balaji Panchapakesan
Keyword(s):  
Carbon Nanotubes ◽  
Low Cost ◽  
Fluid Motion ◽  
Pressure Head ◽  
Low Noise ◽  
Device Fabrication ◽  
Alternative Methods ◽  
Micro Pump ◽  
Photomechanical Actuation ◽  
Optically Induced

We present the design; fabrication and testing of a Polydimethylsiloxane (PDMS)-based microfluidic pump with optically induced membrane actuation. The thin membrane consists of a layer of PDMS (100 μm) and a layer of carbon nanotubes (190 nm). An applied infrared laser opto-mechanically activates the film of carbon nanotubes (CNT), leading to membrane deformation and subsequent fluid motion. Photomechanical actuation offers an alternative way to drive microfluidic devices and provides distinct advantages over alternative methods. The advantages include simplistic, low-cost device fabrication, Wireless actuation, remote controllability electrical–mechanical decoupling, low noise and the elimination of electrical circuits. The performance of this pump in terms of pressure head and flow rate is substantially high. In addition, the micro pump is self-priming and insensitive to particles and bubbles in the pumped media.

scholarly journals IMPLEMENTATION OF A SPECTROPHOTOMETER TEACHING AND LOW COST: APPLICATION IN PHYSICS AND CHEMISTRY LABORATORIES FAFISM

2014 ◽  
Vol 39 (1) ◽  
pp. 131
Author(s):  
Kátia Isabel Milagres ◽  
Camila Rodrigues Amaral ◽  
Érica M. da Silva Santos ◽  
Tarcísio B. Marques ◽  
Guilherme De O. Gomes
Keyword(s):  
Visual Field ◽  
School Improvement ◽  
Chemical Analysis ◽  
Low Cost ◽  
Operating Cost ◽  
Practical Solution ◽  
Quantitative Technique ◽  
Physical Chemical ◽  
The Cost ◽  
Analytical Laboratories

The photometry in the visual field has wide application in analytical laboratories and research physical, chemical, biochemical, pharmacological, etc. It is essential that students of physics and chemistry have knowledge about this quantitative technique. One obstacle to the widespread use of this technique is the cost of equipment and materials to be used. The objective of this work is the introduction of a photometer didactic, whose construction and technique with a low operating cost and the easy using and producing results, as a practical solution to put school improvement. The features highlighted in the work do the proposed photometer an economically viable alternative tool for chemical analysis in the laboratories of the Faculty for research and / or teaching.

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