A Sparse Matrix Screen to Establish Initial Conditions for Protein Renaturation

1995 ◽  
Vol 230 (1) ◽  
pp. 8-15 ◽  
Author(s):  
A. Hofmann ◽  
M. Tai ◽  
W. Wong ◽  
C.G. Glabe
2005 ◽  
Vol 38 (5) ◽  
pp. 847-850 ◽  
Author(s):  
Anne B. Senger ◽  
Timothy C. Mueser

Initial crystallization conditions are typically discovered using commercially available sparse-matrix screens. Positive results are then refined using some type of expansion tray. For example, coarse and shallow gradients can be prepared which vary single chemical parameters around the initial conditions in a grid-screen format. Expansion trays are customarily formulated using numerous volume calculations and pipetting stock solutions into individual wells. This tedious process is plagued by pipetting errors, including differences in viscosity, small volumes with large dilutions, evaporation and poor mixing. Here we present a simple method to standardize expansion-tray formats. Instead of using independent well-volume calculations, the initial and final conditions are formulated and gradients (A/B gradients) are prepared using standardized pipetting maps. These step gradients can be prepared by adding decreasing amounts of the initial (A) solution to consecutive wells followed by the addition of the final (B) solution with increasing volume. This simple idea can be applied to both coarse and shallow grids where the pipetting errors are confined within the boundaries defined by the A and B solutions. Programmable electronic pipettes and robotic liquid handlers can be used to prepare the standardized A/B gradients rapidly, regardless of the components, eliminating reprogramming between trays.


Methodology ◽  
2015 ◽  
Vol 11 (3) ◽  
pp. 89-99 ◽  
Author(s):  
Leslie Rutkowski ◽  
Yan Zhou

Abstract. Given a consistent interest in comparing achievement across sub-populations in international assessments such as TIMSS, PIRLS, and PISA, it is critical that sub-population achievement is estimated reliably and with sufficient precision. As such, we systematically examine the limitations to current estimation methods used by these programs. Using a simulation study along with empirical results from the 2007 cycle of TIMSS, we show that a combination of missing and misclassified data in the conditioning model induces biases in sub-population achievement estimates, the magnitude and degree to which can be readily explained by data quality. Importantly, estimated biases in sub-population achievement are limited to the conditioning variable with poor-quality data while other sub-population achievement estimates are unaffected. Findings are generally in line with theory on missing and error-prone covariates. The current research adds to a small body of literature that has noted some of the limitations to sub-population estimation.


Author(s):  
Musraini M Musraini M ◽  
Rustam Efendi ◽  
Rolan Pane ◽  
Endang Lily

Barisan Fibonacci dan Lucas telah digeneralisasi dalam banyak cara, beberapa dengan mempertahankan kondisi awal, dan lainnya dengan mempertahankan relasi rekurensi. Makalah ini menyajikan sebuah generalisasi baru barisan Fibonacci-Lucas yang didefinisikan oleh relasi rekurensi B_n=B_(n-1)+B_(n-2),n≥2 , B_0=2b,B_1=s dengan b dan s bilangan bulat  tak negatif. Selanjutnya, beberapa identitas dihasilkan dan diturunkan menggunakan formula Binet dan metode sederhana lainnya. Juga dibahas beberapa identitas dalam bentuk determinan.   The Fibonacci and Lucas sequence has been generalized in many ways, some by preserving the initial conditions, and others by preserving the recurrence relation. In this paper, a new generalization of Fibonacci-Lucas sequence is introduced and defined by the recurrence relation B_n=B_(n-1)+B_(n-2),n≥2, with ,  B_0=2b,B_1=s                          where b and s are non negative integers. Further, some identities are generated and derived by Binet’s formula and other simple methods. Also some determinant identities are discussed.


2020 ◽  
Vol 10 (1) ◽  
pp. 86
Author(s):  
Mujiem Mujiem

This research is a classroom action research that aims to improve the ability of teachers to apply the problem centered learning model of learning in the Elementary School 187/ X Bangun Karya, Academic Year 2019/2020. The subject of this study was a teacher at 187 / X Bangun Karya Elementary School, Rantau Rasau District, Tanjung Jabung Timur District, Jambi Province. This class action research was carried out in two cycles, each cycle consisting of two meetings. The results of the evaluation are converted into a recapitulation table of the results of cycle I. The conversion results state that the research has not yet reached the target, it needs to be continued with cycle II. The results of observers in the implementation phase of the second cycle showed that all parts of the learning activities were going well, so that there were no more parts of the learning activities that needed to be improved. While the results of the second cycle are converted with the results of the recapitulation table states that the study has reached the target limit of completeness criteria in the first cycle that is equal to 50% and an average of 68.7 in the initial conditions of improvement in the second cycle completeness criteria to be 100% and the average namely 91.7 states that the Focus Group Discission can improve the ability of teachers to apply the Problem Centered Learning learning model in learning in 187 / X Public Elementary School Build Work Year 2019/2020.


Author(s):  
Alexander S. Lelekov ◽  
Anton V. Shiryaev

The work is devoted to modeling the growth of optically dense microalgae cultures in natural light. The basic model is based on the idea of the two-stage photoautotrophic growth of microalgae. It is shown that the increase in the intensity of sunlight in the first half of the day can be described by a linear equation. Analytical equations for the growth of biomass of microalgae and its macromolecular components are obtained. As the initial conditions, it is assumed that at the time of sunrise, the concentration of reserve biomass compounds is zero. The simulation results show that after sunrise, the growth of the microalgae culture is due only to an increase in the reserve part of the biomass, while the structural part practically does not change over six hours. Changes in the ratio of the reserve and structural parts of the biomass indicate a change in the biochemical composition of cells.


2012 ◽  
Vol 8 (1) ◽  
pp. 1-15
Author(s):  
Gy. Sitkei

Motion of particles with air resistance (e.g. horizontal and inclined throwing) plays an important role in many technological processes in agriculture, wood industry and several other fields. Although, the basic equation of motion of this problem is well known, however, the solutions for practical applications are not sufficient. In this article working diagrams were developed for quick estimation of the throwing distance and the terminal velocity. Approximate solution procedures are presented in closed form with acceptable error. The working diagrams provide with arbitrary initial conditions in dimensionless form of general validity.


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