Cryo-EM Performance Testing of Hardware and Data Acquisition Strategies

Microscopy ◽  
2021 ◽  
Author(s):  
Radostin Danev ◽  
Haruaki Yanagisawa ◽  
Masahide Kikkawa
Keyword(s):  
Data Acquisition ◽  
Performance Testing ◽  
Test Sample ◽  
Critical Parameters ◽  
Site Specific ◽  
Cryo Electron Microscopy ◽  
Beam Image ◽  
Acquisition Strategies ◽  
Limited Experience ◽  
Coma Aberration

Abstract The increasing popularity and adoption rate of cryo-electron microscopy is evidenced by a growing number of new microscope installations around the world. The quality and reliability of the instruments improved dramatically in recent years, but site-specific issues or unnoticed problems during installation could undermine productivity. Newcomers to the field may also have limited experience and/or low confidence in the capabilities of the equipment or their own skills. Therefore, it is recommended to perform an initial test of the complete cryo-EM workflow with an ‘easy’ test sample, such as apoferritin, before starting work with real and challenging samples. Analogous test experiments are also recommended for quantification of new data acquisition approaches or imaging hardware. Here, we present the results from our initial tests of a recently installed Krios G4 electron microscope equipped with two latest generation direct electron detector cameras—Gatan K3 and Falcon 4. Three beam-image shift-based data acquisition strategies were also tested. We detail the methodology and discuss the critical parameters and steps for performance testing. The two cameras performed equally, and the single and multi-shot per-hole acquisition schemes produced comparable results. We also evaluated the effects of environmental factors and optical flaws on data quality. Our results reaffirmed the exceptional performance of the software aberration correction in Relion in dealing with severe coma aberration. We hope that this work will help cryo-EM teams in their testing and troubleshooting of hardware and data collection approaches.

scholarly journals An Adaptive Genetic Algorithm of Adjusting Sensor Acquisition Frequency

Sensors ◽  
2020 ◽  
Vol 20 (4) ◽  
pp. 990 ◽  
Author(s):  
Feng Chen ◽  
Shouzhi Xu ◽  
Ying Zhao ◽  
Hui Zhang
Keyword(s):  
Genetic Algorithm ◽  
Data Acquisition ◽  
Reducing Power ◽  
Sensor Nodes ◽  
Monitoring Data ◽  
Adaptive Genetic Algorithm ◽  
Environment Monitoring ◽  
Wireless Sensor Nodes ◽  
Acquisition Strategies

Portable meteorological stations are widely applied in environment monitoring systems, but they are always limited in power-supplying due to no cable power, especially in long-term monitoring scenarios. Reducing power consumption by adjusting a suitable frequency of sensor acquisition is very important for wireless sensor nodes. The regularity of historical environment data from a monitoring system is analyzed, and then an optimization model of an adaptive genetic algorithm for environment monitoring data acquisition strategies is proposed to lessen sampling frequency. According to the historical characteristics, the algorithm dynamically changes the recent data acquisition frequency so as to collect data with a smaller acquisition frequency, which will reduce the energy consumption of the sensor. Experiment results in a practical environment show that the algorithm can greatly reduce the acquisition frequency, and can obtain the environment monitoring data changing curve with less error compared with the high-frequency acquisition of fixed frequency.

A Modern Laboratory for Hydraulic Turbine and Pump/Turbine Model Performance Testing

1974 ◽  
Vol 96 (1) ◽  
pp. 55-61
Author(s):  
G. R. Frey ◽  
R. L. Rohrbaugh ◽  
W. G. Whippen
Keyword(s):  
Data Acquisition ◽  
Model Performance ◽  
Performance Testing ◽  
Hydraulic Turbine ◽  
Model Testing ◽  
Testing Time ◽  
Laboratory Design ◽  
Electronic Instrumentation ◽  
Hydraulic Turbines ◽  
Improved Performance

Increased demands for higher performance, reliability, and versatility from hydraulic turbines and pump/turbines have dictated that manufacturers improve their model testing facilities to thoroughly evaluate individual designs as required by customer specifications. Advances in supporting technology, particularly electronic instrumentation, data acquisition, and motor/generator control, have significantly improved performance data and have reduced testing time to a minimum. This paper discusses a new laboratory design, incorporated by the Hydro-Turbine Division of Allis-Chalmers Corporation for model testing, including the building, the flexible test circuits, the data acquisition system, the power generation system, and the model test stand.

Influence of Heat Treatment Process on Tensile Fracture Behavior of Cu-Based Metallic Glass

2013 ◽  
Vol 742 ◽  
pp. 170-174
Author(s):  
Ling Zhang ◽  
De Chun Luo ◽  
Xiang Bin Yi
Keyword(s):  
Tensile Strength ◽  
Fracture Behavior ◽  
Isothermal Annealing ◽  
Flow Behavior ◽  
Performance Testing ◽  
Fracture Morphology ◽  
Test Sample ◽  
Fracture Pattern ◽  
Tensile Fracture ◽  
Venation Pattern

The Cu50Zr42Al8dumbbell-shaped alloy with original scale distance of 25 mm and diameters of 4.5 mm was prepared by the suspend melting-copper mould suction casting. The structure tensile performance testing and the fracture morphology observation of Cu50Zr42Al8BMG as-quenched and 400k/1h isothermal annealing were investigated, respectively. The deformation and fracture behavior of samples had been studied. The results showed that the structure of all samples were composed of amorphous phase and possess good glass formation abilitysample as-quenched is always in the elastic deformation stage during elongation and the tensile strength is 629MPa; however ,for specimen after 400k/1h isothermal annealing ,the yield phenomenon occurs before breaking and the maximum tensile strength is 755Mpa, and the same time, the maximum failure extensibility increases from 0.56% for sample as-quenched to 0.80% for 400k/1h isothermal annealing. The fracture pattern of test sample at annealing assumes venation pattern, which is similar to fractography of Cu50Zr42Al8BMG as-quenched, in addition, which appeared apparent viscous flow behavior and melting characteristics.

Well Data Acquisition Strategies

2000 ◽  
Author(s):  
A. Louis ◽  
C. Boehm ◽  
J. Sancho ◽  
S. Carlin ◽  
R. Cerri ◽  
...  
Keyword(s):  
Data Acquisition ◽  
Acquisition Strategies ◽  
Well Data

scholarly journals Comparison of Data Acquisition Strategies on Quadrupole Ion Trap Instrumentation for Shotgun Proteomics

2014 ◽  
Vol 25 (12) ◽  
pp. 2048-2059 ◽  
Author(s):  
Jesse D. Canterbury ◽  
Gennifer E. Merrihew ◽  
Michael J. MacCoss ◽  
David R. Goodlett ◽  
Scott A. Shaffer
Keyword(s):  
Data Acquisition ◽  
Ion Trap ◽  
Shotgun Proteomics ◽  
Quadrupole Ion Trap ◽  
Acquisition Strategies

scholarly journals Benchmarking cryo-EM single particle analysis workflow

2018 ◽  
Author(s):  
Laura Y. Kim ◽  
William J. Rice ◽  
Edward T. Eng ◽  
Mykhailo Kopylov ◽  
Anchi Cheng ◽  
...  
Keyword(s):  
Single Particle ◽  
Test Sample ◽  
Particle Analysis ◽  
Specimen Preparation ◽  
Software Components ◽  
Rabbit Muscle ◽  
Single Particle Analysis ◽  
Skill Levels ◽  
Cryo Electron Microscopy ◽  
Analysis Workflow

AbstractCryo electron microscopy facilities running multiple instruments and serving users with varying skill levels need a robust and reliable method for benchmarking both the hardware and software components of their single particle analysis workflow. The workflow is complex, with many bottlenecks existing at the specimen preparation, data collection and image analysis steps; the samples and grid preparation can be of unpredictable quality, there are many different protocols for microscope and camera settings, and there is a myriad of software programs for analysis that can depend on dozens of settings chosen by the user. For this reason, we believe it is important to benchmark the entire workflow, using a standard sample and standard operating procedures, on a regular basis. This provides confidence that all aspects of the pipeline are capable of producing maps to high resolution. Here we describe benchmarking procedures using a test sample, rabbit muscle aldolase.

scholarly journals Networks of HIV-1 envelope glycans maintain antibody epitopes in the face of glycan additions and deletions

2020 ◽  
Author(s):  
Gemma E. Seabright ◽  
Christopher A. Cottrell ◽  
Marit J. van Gils ◽  
Alessio D’addabbo ◽  
David J. Harvey ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Neutralizing Antibodies ◽  
Broadly Neutralizing Antibodies ◽  
Site Specific ◽  
Glycan Analysis ◽  
Cryo Electron Microscopy ◽  
Immunogen Design ◽  
The Face ◽  
Antibody Epitopes ◽  
Hiv 1

SUMMARYNumerous broadly neutralizing antibodies (bnAbs) have been identified that target the glycans of the HIV-1 envelope spike. Neutralization breadth is notable given that glycan processing can be substantially influenced by the presence or absence of neighboring glycans. Here, using a stabilized recombinant envelope trimer, we investigate the degree to which mutations in the glycan network surrounding an epitope impact the fine glycan processing of antibody targets. Using cryo-electron microscopy and site-specific glycan analysis, we reveal the hierarchy of importance of glycans in the formation of the 2G12 bnAb epitope, and show that the epitope is only subtly impacted by variations in the glycan network. In contrast, we show that the PG9 and PG16 glycan-based epitopes at the trimer apex are dependent on the presence of the highly conserved surrounding glycans. Glycan networks underpin the conservation of bnAb epitopes and are an important parameter in immunogen design.

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