Uniformity of Magnification from Different Electron Microscopes

Author(s):  
Godfrey C. Hoskins ◽  
V. Williams ◽  
V. Allison

The method demonstrated is an adaptation of a proven procedure for accurately determining the magnification of light photomicrographs. Because of the stability of modern electrical lenses, the method is shown to be directly applicable for providing precise reproducibility of magnification in various models of electron microscopes.A readily recognizable area of a carbon replica of a crossed-line diffraction grating is used as a standard. The same area of the standard was photographed in Phillips EM 200, Hitachi HU-11B2, and RCA EMU 3F electron microscopes at taps representative of the range of magnification of each. Negatives from one microscope were selected as guides and printed at convenient magnifications; then negatives from each of the other microscopes were projected to register with these prints. By deferring measurement to the print rather than comparing negatives, correspondence of magnification of the specimen in the three microscopes could be brought to within 2%.

2020 ◽  
Vol 12 (7) ◽  
pp. 2767 ◽  
Author(s):  
Víctor Yepes ◽  
José V. Martí ◽  
José García

The optimization of the cost and CO 2 emissions in earth-retaining walls is of relevance, since these structures are often used in civil engineering. The optimization of costs is essential for the competitiveness of the construction company, and the optimization of emissions is relevant in the environmental impact of construction. To address the optimization, black hole metaheuristics were used, along with a discretization mechanism based on min–max normalization. The stability of the algorithm was evaluated with respect to the solutions obtained; the steel and concrete values obtained in both optimizations were analyzed. Additionally, the geometric variables of the structure were compared. Finally, the results obtained were compared with another algorithm that solved the problem. The results show that there is a trade-off between the use of steel and concrete. The solutions that minimize CO 2 emissions prefer the use of concrete instead of those that optimize the cost. On the other hand, when comparing the geometric variables, it is seen that most remain similar in both optimizations except for the distance between buttresses. When comparing with another algorithm, the results show a good performance in optimization using the black hole algorithm.


2021 ◽  
Vol 5 (2) ◽  
pp. 32
Author(s):  
Esmehan Uçar ◽  
Sümeyra Uçar ◽  
Fırat Evirgen ◽  
Necati Özdemir

It is possible to produce mobile phone worms, which are computer viruses with the ability to command the running of cell phones by taking advantage of their flaws, to be transmitted from one device to the other with increasing numbers. In our day, one of the services to gain currency for circulating these malignant worms is SMS. The distinctions of computers from mobile devices render the existing propagation models of computer worms unable to start operating instantaneously in the mobile network, and this is particularly valid for the SMS framework. The susceptible–affected–infectious–suspended–recovered model with a classical derivative (abbreviated as SAIDR) was coined by Xiao et al., (2017) in order to correctly estimate the spread of worms by means of SMS. This study is the first to implement an Atangana–Baleanu (AB) derivative in association with the fractional SAIDR model, depending upon the SAIDR model. The existence and uniqueness of the drinking model solutions together with the stability analysis are shown through the Banach fixed point theorem. The special solution of the model is investigated using the Laplace transformation and then we present a set of numeric graphics by varying the fractional-order θ with the intention of showing the effectiveness of the fractional derivative.


Games ◽  
2021 ◽  
Vol 12 (3) ◽  
pp. 53
Author(s):  
Roberto Rozzi

We consider an evolutionary model of social coordination in a 2 × 2 game where two groups of players prefer to coordinate on different actions. Players can pay a cost to learn their opponent’s group: if they pay it, they can condition their actions concerning the groups. We assess the stability of outcomes in the long run using stochastic stability analysis. We find that three elements matter for the equilibrium selection: the group size, the strength of preferences, and the information’s cost. If the cost is too high, players never learn the group of their opponents in the long run. If one group is stronger in preferences for its favorite action than the other, or its size is sufficiently large compared to the other group, every player plays that group’s favorite action. If both groups are strong enough in preferences, or if none of the groups’ sizes is large enough, players play their favorite actions and miscoordinate in inter-group interactions. Lower levels of the cost favor coordination. Indeed, when the cost is low, in inside-group interactions, players always coordinate on their favorite action, while in inter-group interactions, they coordinate on the favorite action of the group that is stronger in preferences or large enough.


1994 ◽  
Vol 15 (6) ◽  
pp. 297-300 ◽  
Author(s):  
Michael P. Dohm ◽  
James B. Benjamin ◽  
Jeffrey Harrison ◽  
John A. Szivek

A biomechanical study was undertaken to evaluate the relative stability of three types of internal fixation used for ankle arthrodesis. Crossed screw fixation, RAF fibular strut fixation, and T-plate fixation were tested in 30 cadaver ankles using an MTS machine. T-plate fixation consistantly provided the stiffest construct when compared with the other types of fixation. Failure occurred by distraction of bony surfaces, posterior to the plane of fixation, in the crossed screw and RAF groups. In contrast, failure in the T-plate group occurred through compression of bone anterior to the midcoronal plane of the tibia. Although the stability of fixation is only one factor in determining the success or failure of ankle arthrodesis, the results of this study would support T-plate fixation over the other forms tested.


2002 ◽  
Vol 184 (4) ◽  
pp. 889-894 ◽  
Author(s):  
Yi Wei ◽  
David H. Bechhofer

ABSTRACT The tet(L) gene of Bacillus subtilis confers low-level tetracycline (Tc) resistance. Previous work examining the >20-fold-inducible expression of tet(L) by Tc demonstrated a 12-fold translational induction. Here we show that the other component of tet(L) induction is at the level of mRNA stabilization. Addition of a subinhibitory concentration of Tc results in a two- to threefold increase in tet(L) mRNA stability. Using a plasmid-borne derivative of tet(L) with a large in-frame deletion of the coding sequence, the mechanism of Tc-induced stability was explored by measuring the decay of tet(L) mRNAs carrying specific mutations in the leader region. The results of these experiments, as well as experiments with a B. subtilis strain that is resistant to Tc due to a mutation in the ribosomal S10 protein, suggest different mechanisms for the effects of Tc on translation and on mRNA stability. The key role of the 5" end in determining mRNA stability was confirmed in these experiments. Surprisingly, the stability of several other B. subtilis mRNAs was also induced by Tc, which indicates that addition of Tc may result in a general stabilization of mRNA.


Author(s):  
Ebrahim Esmailzadeh ◽  
Gholamreza Nakhaie-Jazar ◽  
Bahman Mehri

Abstract The transverse vibrating motion of a simple beam with one end fixed while driven harmonically along its axial direction from the other end is investigated. For a special case of zero value for the rigidity of the beam, the system reduces to that of a vibrating string with the corresponding equation of its motion. The sufficient condition for the periodic solution of the beam is then derived by means of the Green’s function and Schauder’s fixed point theorem. The criteria for the stability of the system is well defined and the condition for which the performance of the beam behaves as a nonlinear function is stated.


Author(s):  
Nazarova Shakhlo ◽  

Like Uzbek, Korean belongs to the Altaic language family, and the sources assume that: a) Korean word forms are agglutinative schemes based on the stem + affix, b) sentences are based on the syntactic scheme of “possessive + second part + cut”, c) the stability of word stress and expiratory character, etc. Additionaly in a word structure the following can be divided: 1) 뾐ꭅ덽: 뾐 + ꭅ + 덽 ; 頝ꃝꍡ겑꽽鲙: 頝 + -ꃝꍡ- + -겑- + -꽽- + -鲙such that cores and appendages can be joined one after the other and separated; 2) according to the function of affix morphemes, «뾐-, -덽-, -ꃝꍡ-» word building, «-겑-, -꽽-, -鲙» 3) the formation of transpositive and non-transpositive artificial words by means of word-forming suffixes, 4) the relative freedom of the transpositive connection between independent, auxiliary words and morphemes also point to this genetic connection.


2010 ◽  
Vol 44-47 ◽  
pp. 794-798 ◽  
Author(s):  
Xin Ma

The stability of cooperation contract is the result of abandon opportunistic behavior in the process of repeated games among the enterprise and the other subjects in the supply chain from long-term interests, and is also the foundation of healthy development for the whole supply chain. But in real life cooperation contract instability everywhere for a variety of reasons, such as ethical considerations, institutional factors, cultural factors and special reasons during the transition period and so on. From the perspective of information economics and game theory, the main game process of cooperation between enterprise and the other subjects in supply chain is not only the game of information, but also the game of interests. Information structure and the interesting structure are the important factors for the subjects of the game of the implementation of decisions and the basic contractual constraints for cooperative game equilibrium. Cooperation behaviors among the enterprise and the other subjects in the supply chain were studied on the basis of game theory, and the stability of cooperation contract is also being discussed in this paper.


1974 ◽  
Vol 14 (3) ◽  
pp. 505-521
Author(s):  
L. F. LACOUR ◽  
B. WELLS

With the use of the light and electron microscopes, the chromosomes of Fritillaria lanceolata and Scilla sibirica are shown to differ in respect of the heterochromatin they contain. In root meristems of the former, the heterochromatic regions (H-segments) were recognizable at all phases of the mitotic cycle by their slighter opacity to electrons than that of euchromatic parts. This was due both to less tight packing of the chromatin fibrils and lower opacity of the fibrils themselves, even though both had the same diameter, about 3 nm. In root tips of the Scilla, the heterochromatin was invariably of similar opacity to euchromatin and thus only recognizable at telophase and interphase as large chromocentres. The opacity to electrons in the heterochromatin of the 2 species, was at all times closely paralleled by the staining behaviour seen with the light microscope in sections (0.07-0.5 µm in thickness) stained with toluidine blue. The disparity in the Fritillaria, as seen in sections with the light microscope, in respect of the stainability of the hetero- and euchromatin, was masked in Feulgen squash preparations of root tips from plants grown at 18-20 °C; at metaphase by the thickness of the chromosomes and at interphase by the density of the chromocentres. When, on the other hand, the plants were grown for 4 days at 2 °C, the masking effect of thickness was circumvented in metaphase chromosomes by differential super-contraction in euchromatin. The implications of these findings in respect to previous interpretations of the differential reactivity of H-segments to low temperature, as well as the phenomenon of enhanced and reduced fluorescence in these segments with fluorochromes are discussed.


2021 ◽  
Vol 10 (1) ◽  
pp. 37-40
Author(s):  
Vesna Savić ◽  
Milica Martinović ◽  
Ivana Nešić ◽  
Jelena Živković ◽  
Ivana Gajić

The aim of this study was to compare the stability and texture of three zinc oxide suspensions with different additives. Suspension 1 was made as official magistral formulation Suspensio album 7.5% from Formulae magistrales 2008. Suspension 2 was prepared when 1% carbomer gel was added to suspension 1 and suspension 3 was prepared when polysorbate 20 was added to suspension 2. After stability tests, texture analysis was performed on all suspensions. Following parameters were measured: hardness cycle 1, hardness cycle 2, cohesiveness, adhesiveness, resilience and springiness. The study showed that suspension 3 had the lowest value of hardness, and therefore the best spreadability. Also, suspension 3 was the least sticky of all three, since it was characterized with the lowest adhesiveness. Further, suspension 3 was the most cohesive and is predicted to withstand the stress during packing and use longer than others. On the other hand, the highest values of resilience and springiness were detected for suspension 1, while the lowest was related to suspension 2. Therefore, the best textural characteristics were assigned to suspension 3. This result is in accordance with the results of performed stability tests. The results of our study offer insight into potential improvements of the current magistral formulation Suspensio album 7.5%.


Sign in / Sign up

Export Citation Format

Share Document