scholarly journals Longevity of Raw and Lyophilized Crude Urease Extracts

2021 ◽  
Vol 2 (2) ◽  
pp. 325-334
Author(s):  
Neda Javadi ◽  
Hamed Khodadadi Tirkolaei ◽  
Nasser Hamdan ◽  
Edward Kavazanjian
Keyword(s):  
Crude Extract ◽  
Room Temperature ◽  
Low Cost ◽  
Extraction Process ◽  
Crude Extracts ◽  
Simple Extraction ◽  
Commercial Applications ◽  
Stable Source ◽  
The Stability ◽  
The Cost

The stability (longevity of activity) of three crude urease extracts was evaluated in a laboratory study as part of an effort to reduce the cost of urease for applications that do not require high purity enzyme. A low-cost, stable source of urease will greatly facilitate engineering applications of urease such as biocementation of soil. Inexpensive crude extracts of urease have been shown to be effective at hydrolyzing urea for carbonate precipitation. However, some studies have suggested that the activity of a crude extract may decrease with time, limiting the potential for its mass production for commercial applications. The stability of crude urease extracts shown to be effective for biocementation was studied. The crude extracts were obtained from jack beans via a simple extraction process, stored at room temperature and at 4 ℃, and periodically tested to evaluate their stability. To facilitate storage and transportation of the extracted enzyme, the longevity of the enzyme following freeze drying (lyophilization) to reduce the crude extract to a powder and subsequent re-hydration into an aqueous solution was evaluated. In an attempt to improve the shelf life of the lyophilized extract, dextran and sucrose were added during lyophilization. The stability of purified commercial urease following rehydration was also investigated. Results of the laboratory tests showed that the lyophilized crude extract maintained its activity during storage more effectively than either the crude extract solution or the rehydrated commercial urease. While incorporating 2% dextran (w/v) prior to lyophilization of the crude extract increased the overall enzymatic activity, it did not enhance the stability of the urease during storage.

scholarly journals HAT-field: a very cheap, robust and quantitative point-of-care serological test for Covid-19.

2022 ◽  
Author(s):  
Etienne Joly ◽  
Agnes Maurel Ribes
Keyword(s):  
Room Temperature ◽  
Serological Test ◽  
Point Of Care ◽  
Low Cost ◽  
Single Step ◽  
Test Protocol ◽  
Laboratory Equipment ◽  
Human Red Blood Cells ◽  
The Stability ◽  
Disposable Equipment

We have recently described a very simple and cheap serological test called HAT to detect antibodies directed against the RBD of the SARS-Cov-2 virus. HAT is based on hemagglutination, triggered by a single reagent (IH4-RBD) comprised of the viral RBD domain fused to a nanobody specific for glycophorin, which is expressed at very high levels at the surface of human red blood cells (RBCs). One of the main initial goals of this study was to devise a test protocol that would be sensitive and reliable, yet require no specialized laboratory equipment such as adjustable pipets, so that it could be performed in the most remote corners of the world by people with minimal levels of training. Because antibody levels against the viral RBD have been found to correlate closely with sero-neutralisation titers, and thus with protection against reinfection, it has become obvious during the course of this study that making this test reliably quantitative would be a further significant advantage. We have found that, in PBN, a buffer which contains BSA and sodium azide, IH4-RBD is stable for over 6 months at room temperature, and that PBN also improves HAT performance compared to using straight PBS. We also show that performing HAT at either 4°C, room temperature or 37°C has minimal influence on the results, and that quantitative evaluation of the levels of antibodies directed against the SARS-CoV-2 RBD can be achieved in a single step using titration of the IH4-RBD reagent. The HAT-field protocol described here requires only very simple disposable equipment and a few microliters of whole blood, such as can be obtained by finger prick. Because it is based on a single soluble reagent, the test can be adapted very simply and rapidly to detect antibodies against variants of the SARS-CoV-2, or conceivably against different pathogens. HAT-field appears well suited to provide quantitative assessments of the serological protection of populations as well as individuals, and given its very low cost, the stability of the IH4-RBD reagent in the adapted buffer, and the simplicity of the procedure, could be deployed pretty much anywhere, including in the poorest countries and the most remote corners of the globe.

The Design and Simulation of Low-Cost and Super-Applicability Flight Control System of Super-Size UAV

2012 ◽  
Vol 466-467 ◽  
pp. 1156-1161
Author(s):  
Liu Rong ◽  
Yu Ping Lu
Keyword(s):  
Control System ◽  
Flight Control ◽  
Low Cost ◽  
Control Technique ◽  
Flight Control System ◽  
Flight Curve ◽  
Aerial Vehicle ◽  
The Stability ◽  
High Flexibility ◽  
The Cost

In this paper, considering the stability and robustness of the aircraft, the flight control system is designed following the aspect of high flexibility and low cost. Comparing with the flight control system of super-size high-subsonic Unmanned Aerial Vehicle (UAV) in the world, the system presented in this paper has adopted the inimitable control technique of flying-off course、low-cost combinatorial navigation strategy and the advanced safety scheme, which can guarantee the performance, degrade the cost and extend the airspace and groundspace of the aircraft.Through quite a few simulations, the results show that this system can guarantee the attitude and altitude stable. The error between the flight path and programming path is very small. Flight curve is prefect; and the system performances can be achieved completely.

scholarly journals Effect of Hafnium Addition on the Hydrogenation Process of TiFe Alloy

Energies ◽  
2019 ◽  
Vol 12 (18) ◽  
pp. 3477 ◽  
Author(s):  
Volatiana Razafindramanana ◽  
Stéphane Gorsse ◽  
Jacques Huot ◽  
Jean Louis Bobet
Keyword(s):  
Room Temperature ◽  
Low Cost ◽  
Plateau Pressure ◽  
Hydrogenation Process ◽  
Practical Applications ◽  
Hydrogen Capacity ◽  
Arc Melting ◽  
Cast Alloys ◽  
The Cost ◽  
Positive Effect

The alloy TiFe has interesting hydrogen storage properties for practical applications: low cost, operation at room temperature, and good hydrogen capacity. However, the first hydrogenation is difficult and increases the cost of the alloy. In this work, we studied the effect of adding hafnium to TiFe in order to enhance the first hydrogenation process. TiFe + x Hf alloys, with x = 0, 4, 8, 12, and 16 wt.%, were synthesized by arc melting. The microstructure of the as-cast alloys was investigated by scanning electron microscopy and electron microprobe analysis. These alloys consisted of B2-TiFe, C14-Laves, and BCC (Body Centered Cubic) phases. A minimum of 8 wt.% of hafnium is required to obtain an enhancement of the first hydrogenation. In the first hydrogenation, the material reaches its maximal hydrogen capacity in less than two hours at room temperature and under 20 bars of hydrogen. Hafnium addition also had the effect of lowering the plateau pressure in the pressure-composition isotherm. It could be concluded that hafnium has a positive effect on the activation properties of TiFe.

scholarly journals Battery-Powered Portable Rotary Real-Time Fluorescent qPCR with Low Energy Consumption, Low Cost, and High Throughput

Biosensors ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 49
Author(s):  
Limin He ◽  
Benliang Sang ◽  
Wenming Wu
Keyword(s):  
Energy Consumption ◽  
Real Time ◽  
Low Cost ◽  
Average Power ◽  
Pcr Amplification ◽  
Melting Curves ◽  
Average Power Consumption ◽  
The Stability ◽  
Rotary Structure ◽  
The Cost

The traditional qPCR instrument is bulky, expensive, and inconvenient to carry, so we report a portable rotary real-time fluorescent PCR (polymerase chain reaction) that completes the PCR amplification of DNA in the field, and the reaction can be observed in real-time. Through the analysis of a target gene, namely pGEM-3Zf (+), the gradient amplification and melting curves are compared to commercial devices. The results confirm the stability of our device. This is the first use of a mechanical rotary structure to achieve gradient amplification curves and melting curves comparable to commercial instruments. The average power consumption of our system is about 7.6 W, which is the lowest energy consumption for real-time fluorescence quantification in shunting PCR and enables the use of our device in the field thanks to its self-contained power supply based on a lithium battery. In addition, all of the equipment costs only about 710 dollars, which is far lower than the cost of a commercial PCR instrument because the control system through mechanical displacement replaces the traditional TEC (thermoelectric cooler) temperature control. Moreover, the equipment has a low technical barrier, which can suit the needs of non-professional settings, with strong repeatability.

scholarly journals Optimised CO2-containing medium for in vitro culture and transportation of mouse preimplantation embryos without CO2 incubator

PLoS ONE ◽  
2021 ◽  
Vol 16 (12) ◽  
pp. e0260645
Author(s):  
Yasuyuki Kikuchi ◽  
Sayaka Wakayama ◽  
Daiyu Ito ◽  
Masatoshi Ooga ◽  
Teruhiko Wakayama
Keyword(s):  
Embryo Culture ◽  
Room Temperature ◽  
Low Cost ◽  
Culture Method ◽  
Developmental Rate ◽  
Blastocyst Stage ◽  
Preimplantation Embryos ◽  
The Cost ◽  
Mouse Embryo Culture

Conventional in vitro culture and manipulation of mouse embryos require a CO2 incubator, which not only increases the cost of performing experiments but also hampers the transport of embryos to the other laboratories. In this study, we established and tested a new CO2 incubator-free embryo culture system and transported embryos using this system. Using an Anaero pouch, which is a CO2 gas-generating agent, to increase the CO2 partial pressure of CZB medium to 4%–5%, 2-cell embryos were cultured to the blastocyst stage in a sealed tube without a CO2 incubator at 37°C. Further, the developmental rate to blastocyst and full-term development after embryo transfer were comparable with those of usual culture method using a CO2 incubator (blastocyst rate: 97% versus 95%, respectively; offspring rate: 30% versus 35%, respectively). Furthermore, using a thermal bottle, embryos were reliably cultured using this system for up to 2 days at room temperature, and live offspring were obtained from embryos transported in this simple and very low-cost manner without reducing the offspring rate (thermal bottle: 26.2% versus CO2 incubator: 34.3%). This study demonstrates that CO2 incubators are not essential for embryo culture and transportation and that this system provides a useful, low-cost alternative for mouse embryo culture and manipulation.

scholarly journals Harmonic Analyzer Using ATMEGA 328P

2019 ◽  
pp. 694-698
Author(s):  
Christie Anil Joseph ◽  
Sumant Sarmokadam ◽  
Dr. Usha Surendra
Keyword(s):  
Power Systems ◽  
Power Supply ◽  
Remote Monitoring ◽  
Low Cost ◽  
Data Logging ◽  
Technical Improvement ◽  
Harmonic Analyzer ◽  
Commercial Applications ◽  
The Cost ◽  
And Control

The technical improvement in Power electronics and Control system industries has made the linear consumer loads to dominate by sensitive and sophisticated non-linear consumer loads. These have a major impact on the power systems, causing increase in harmonics distortion. This paper proposes a hardware design to develop a Harmonic Analyzer along with Arduino ATMEGA 328P, that can be able to analyze up to 15th harmonic of an alternating current power supply. The Harmonic analyzer has been developed considering the cost, accomplished with respect to accuracy, easy modifications through coding, remote monitoring and data logging. The developed low cost handheld product may be used for industrial as well as commercial applications.

A molecular dynamics study of Fe50-XMXAl50 ternary alloy (M=Ag, Pt, Pd)

MRS Advances ◽  
2020 ◽  
Vol 5 (23-24) ◽  
pp. 1185-1193
Author(s):  
C S Mkhonto ◽  
P E Ngoepe ◽  
H R Chauke
Keyword(s):  
Molecular Dynamics ◽  
Room Temperature ◽  
Mechanical Stability ◽  
Low Cost ◽  
Industrial Applications ◽  
Iron Aluminide ◽  
Intermetallic Alloys ◽  
Room Temperature Ductility ◽  
The Stability ◽  
Experimental Findings

ABSTRACTIron aluminide intermetallic alloys are of great importance in many industries due to their excellent oxidation resistance, low cost, low density, resistance to corrosion and good ductility at room temperature. However, these alloys suffer limited room temperature ductility above 873 K. In this paper, a molecular dynamics-based LAMMPS-EAM was used to model Fe50-XMXAl doped systems with either Ag, Pt or Pd. The lattice side preferences of the dopant were deduced from their energy landscape, and Fe sub-lattices showed promising properties. It was found that the addition of Ag, Pt and Pd enhances the stability of Fe50-XMXAl composition. More importantly, Ag and Pd doped systems gave comparable transition temperatures to experimental findings of 1273 K and 1073 K, respectively. Their thermodynamic and the mechanical stability trends showed promising properties for industrial applications, displaying stability at a high temperature below 1300 K.

Methods for the Concentration of Bovine Ac-Globulin (Factor V)

1961 ◽  
Vol 06 (03) ◽  
pp. 435-444 ◽  
Author(s):  
Ricardo H. Landaburu ◽  
Walter H. Seegers
Keyword(s):  
Room Temperature ◽  
Barium Carbonate ◽  
Deae Cellulose ◽  
Reducing Agents ◽  
Factor V ◽  
Isoelectric Precipitation ◽  
Stabilizing Agent ◽  
Bovine Plasma ◽  
The Stability

SummaryAn attempt was made to obtain Ac-globulin from bovine plasma. The concentrates contain mostly protein, and phosphorus is also present. The stability characteristics vary from one preparation to another, but in general there was no loss before 1 month in a deep freeze or before 1 week in an icebox, or before 5 hours at room temperature. Reducing agents destroy the activity rapidly. S-acetylmercaptosuccinic anhydride is an effective stabilizing agent. Greatest stability was at pH 6.0.In the purification bovine plasma is adsorbed with barium carbonate and diluted 6-fold with water. Protein is removed at pH 6.0 and the Ac-globulin is precipitated at pH 5.0. Rivanol and alcohol fractionation is followed by chromatography on Amberlite IRC-50 or DEAE-cellulose. The final product is obtained by isoelectric precipitation.

Advance Protection for Three Phase Induction Motor using Microcontroller Atmega32

2018 ◽  
Vol 8 (1) ◽  
pp. 172
Author(s):  
Karan S Belsare ◽  
Gajanan D Patil
Keyword(s):  
Induction Motor ◽  
Low Cost ◽  
Short Circuit ◽  
Cost Factor ◽  
Protection Scheme ◽  
Three Phase ◽  
The Cost

A low cost and reliable protection scheme has been designed for a three phase induction motor against unbalance voltages, under voltage, over voltage, short circuit and overheating protection. Taking the cost factor into consideration the design has been proposed using microcontroller Atmega32, MOSFETs, relays, small CTs and PTs. However the sensitivity of the protection scheme has been not compromised. The design has been tested online in the laboratory for small motors and the same can be implemented for larger motors by replacing the i-v converters and relays of suitable ratings.

Janus – A New Approach to Air Combat Pilot Training

2019 ◽  
Vol 2019 (4) ◽  
pp. 7-22
Author(s):  
Georges Bridel ◽  
Zdobyslaw Goraj ◽  
Lukasz Kiszkowiak ◽  
Jean-Georges Brévot ◽  
Jean-Pierre Devaux ◽  
...  
Keyword(s):  
Low Cost ◽  
Cost Effective ◽  
High Energy ◽  
Training System ◽  
Embedded Sensors ◽  
Pilot Training ◽  
New Approach ◽  
Combat Aircraft ◽  
Air Combat ◽  
The Cost

Abstract Advanced jet training still relies on old concepts and solutions that are no longer efficient when considering the current and forthcoming changes in air combat. The cost of those old solutions to develop and maintain combat pilot skills are important, adding even more constraints to the training limitations. The requirement of having a trainer aircraft able to perform also light combat aircraft operational mission is adding unnecessary complexity and cost without any real operational advantages to air combat mission training. Thanks to emerging technologies, the JANUS project will study the feasibility of a brand-new concept of agile manoeuvrable training aircraft and an integrated training system, able to provide a live, virtual and constructive environment. The JANUS concept is based on a lightweight, low-cost, high energy aircraft associated to a ground based Integrated Training System providing simulated and emulated signals, simulated and real opponents, combined with real-time feedback on pilot’s physiological characteristics: traditionally embedded sensors are replaced with emulated signals, simulated opponents are proposed to the pilot, enabling out of sight engagement. JANUS is also providing new cost effective and more realistic solutions for “Red air aircraft” missions, organised in so-called “Aggressor Squadrons”.

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