scholarly journals Divalent ligand-monovalent molecule binding

2021 ◽  
Author(s):  
Mathijs Janssen ◽  
Harald Stenmark ◽  
Andreas Carlson
Keyword(s):  
Entire Range ◽  
Total Concentration ◽  
Antigen Detection ◽  
Numerical Results ◽  
Coincidence Detection ◽  
Intermediate Complex ◽  
Protein Depletion ◽  
Cubic Equation ◽  
Binding Event ◽  
Widespread Phenomenon

Simultaneous binding of divalent ligands to two identical molecules is a widespread phenomenon in biology and chemistry. Here, we describe this binding event as a divalent ligand AA that can bind to two identical monovalent molecules B to form the complex AA · B2. Cases where the total concentration [AA]T is either much larger or much smaller than the total concentration [B]T have been studied earlier, but a description of intermediate concentrations is missing. In this paper, we describe the general case of any ratio of ξ ≡ [B]T /[AA]T. We show that the concentration of the intermediate complex AA · B is governed by a cubic equation and discuss several scenarios in which this cubic equation simplifies. Our numerical results, which cover the entire range of 0 < ξ < ∞, are relevant to processes wherein the concentrations of free ligands and proteins both decrease upon binding. Such ligand and protein depletion is expected to be important in cellular contexts, e.g., in antigen detection and in coincidence detection of proteins or lipids.

Sensitivity to Interaural Temporal Disparities of Low- and High-Frequency Neurons in the Superior Olivary Complex. II. Coincidence Detection

1997 ◽  
Vol 78 (3) ◽  
pp. 1237-1247 ◽  
Author(s):  
Ranjan Batra ◽  
Shigeyuki Kuwada ◽  
Douglas C. Fitzpatrick
Keyword(s):  
High Frequency ◽  
Entire Range ◽  
Companion Paper ◽  
Operating Principle ◽  
Coincidence Detection ◽  
Superior Olivary Complex ◽  
Complex Ii ◽  
Basic Operating ◽  
Maximal Discharge

Batra, Ranjan, Shigeyuki Kuwada, and Douglas C. Fitzpatrick. Sensitivity to interaural temporal disparities of low- and high-frequency neurons in the superior olivary complex. II. Coincidence detection. J. Neurophysiol. 78: 1237–1247, 1997. In the companion paper we demonstrated that neurons in the superior olivary complex that were sensitive to interaural temporal disparities (ITDs) could be divided into two broad categories: peak type and trough type. Within these broad categories, many neurons exhibited various types of irregularities in their responses. In the present paper we devise three criteria to determine whether all types of neurons act as coincidence detectors. Each criterion relies on a comparison between the synchrony of the responses to the waveforms at either ear and the “interaural synchrony,” i.e., the response to a cyclically varying ITD. First, a neuron should exhibit synchrony to both the ipsilateral and contralateral waveforms over the entire range to which it is sensitive to ITDs. Second, the ITD that elicits maximal discharge should be equal to the delay required to bring the ipsilateral and contralateral waveforms into coincidence. Third, the strength of interaural synchrony should be predicted by the strengths of synchrony to the waveforms at either ear. We found that most neurons of all types in the superior olivary complex met these criteria. Thus coincidence detection is a basic operating principle for all forms of ITD sensitivity.

Influence of Cracks on Chloride Penetration in Mortar Specimens Subjected to Cyclic Treatment

2014 ◽  
Vol 601 ◽  
pp. 223-226
Author(s):  
Corina Sosdean ◽  
Liviu Marsavina ◽  
Geert de Schutter
Keyword(s):  
Structural Strength ◽  
Total Concentration ◽  
Great Influence ◽  
Steel Corrosion ◽  
Chloride Penetration ◽  
Numerical Results ◽  
Chloride Ingress ◽  
Element Analysis ◽  
Cyclic Treatment ◽  
Penetration Tests

Chloride-induced steel corrosion is worldwide one of the major causes of deterioration of reinforced concrete structures, producing loss of structural strength and stability. One of the most aggressive exposure conditions for concrete is marine environment together with the drying and wetting conditions by tidal and splash action. In such an aggressive environment the presence of cracks has a great influence on chloride ingress.In this paper both the experimental and the numerical results of the influence of artificial cracks on chloride penetration in mortar specimens are presented. The experimental results were obtained using chloride penetration tests on mortar specimens of different sizes, with and without artificial cracks, subjected to a cyclic treatment. Numerical results were obtained using transient finite element analysis by simulating chloride mass diffusionwith COSMOS/FFE realized with the heat transfer modulus T, which was replaced by the total concentration C, and the thermal conductivity Kx, replaced by diffusion coefficient D. Comparisons between the results on chloride penetration concluded that the numerical ones obtained using the mass transfer modulus agree fairly well with the experimental ones. In addition the influence of crack length on chloride ingress was presented.

The Tempo and mode(S) of Prebiotic Evolution

1997 ◽  
Vol 161 ◽  
pp. 419-429 ◽  
Author(s):  
Antonio Lazcano
Keyword(s):  
Origin Of Life ◽  
Organic Compounds ◽  
Biological Evolution ◽  
Current Evidence ◽  
Early Diversification ◽  
Time Period ◽  
The Galaxy ◽  
History Of ◽  
Widespread Phenomenon ◽  
The Origin Of Life

AbstractDifferent current ideas on the origin of life are critically examined. Comparison of the now fashionable FeS/H2S pyrite-based autotrophic theory of the origin of life with the heterotrophic viewpoint suggest that the later is still the most fertile explanation for the emergence of life. However, the theory of chemical evolution and heterotrophic origins of life requires major updating, which should include the abandonment of the idea that the appearance of life was a slow process involving billions of years. Stability of organic compounds and the genetics of bacteria suggest that the origin and early diversification of life took place in a time period of the order of 10 million years. Current evidence suggest that the abiotic synthesis of organic compounds may be a widespread phenomenon in the Galaxy and may have a deterministic nature. However, the history of the biosphere does not exhibits any obvious trend towards greater complexity or «higher» forms of life. Therefore, the role of contingency in biological evolution should not be understimated in the discussions of the possibilities of life in the Universe.

Automation Surprise

2017 ◽  
Vol 7 (1) ◽  
pp. 28-41 ◽  
Author(s):  
Robert J. de Boer ◽  
Karel Hurts
Keyword(s):  
Flight Control ◽  
Representative Sample ◽  
Aviation Safety ◽  
Control Mode ◽  
Cognitive Errors ◽  
Laboratory Studies ◽  
Airline Pilots ◽  
Flight Operations ◽  
Widespread Phenomenon ◽  
Few Data

Abstract. Automation surprise (AS) has often been associated with aviation safety incidents. Although numerous laboratory studies have been conducted, few data are available from routine flight operations. A survey among a representative sample of 200 Dutch airline pilots was used to determine the prevalence of AS and the severity of its consequences, and to test some of the factors leading to AS. Results show that AS is a relatively widespread phenomenon that occurs three times per year per pilot on average but rarely has serious consequences. In less than 10% of the AS cases that were reviewed, an undesired aircraft state was induced. Reportable occurrences are estimated to occur only once every 1–3 years per pilot. Factors leading to a higher prevalence of AS include less flying experience, increasing complexity of the flight control mode, and flight duty periods of over 8 hr. It is concluded that AS is a manifestation of system and interface complexity rather than cognitive errors.

Timing by coincidence detection: What's all the noise about?

2012 ◽  
Author(s):  
Catalin V. Buhusi ◽  
Sorinel Oprisan
Keyword(s):  
Coincidence Detection

F-18-FDG Positron Imaging in Oncological Patients: Gamma Camera Coincidence Detection versus Dedicated PET

1999 ◽  
Vol 38 (04) ◽  
pp. 108-114 ◽  
Author(s):  
H.-J. Kaiser ◽  
U. Cremerius ◽  
O. Sabri ◽  
M. Schreckenberger ◽  
P. Reinartz ◽  
...  
Keyword(s):  
Attenuation Correction ◽  
Spatial Resolution ◽  
Gamma Camera ◽  
Lesion Detection ◽  
Coincidence Detection ◽  
System Sensitivity ◽  
Oncological Patients ◽  
Phantom Studies ◽  
Pet System ◽  
Dedicated Pet

Summary Aim of the present study was to investigate the feasibility of 2-[fluorine-18]-fluoro-2-deoxy-D-glucose (FDG) imaging in oncological patients with a dual head gamma camera modified for coincidence detection (MCD). Methods: Phantom studies were done to determine lesion detection at various lesion-to-background ratios, system sensitivity and spatial resolution. Thirty-two patients with suspected or known malignant disease were first studied with a dedicated full-ring PET system (DPET) applying measured attenuation correction and subsequently with an MCD system without attenuation correction. MCD images were first interpreted without knowledge of the DPET findings. In a second reading, MCD and DPET were evaluated simultaneously. Results: The phantom studies revealed a comparable spatial resolution for DPET and MCD (5.9 × 6.3 × 4.2 mm vs. 5.9 × 6.5 × 6.0 mm). System sensitivity of MCD was less compared to DPET (91 cps/Bq/ml/cmF0V vs. 231 cps/ Bq/ml/cmFOv). At a lesion-to-background ratio of 4:1, DPET depicted a minimal phantom lesion of 1.0 cm in diameter, MCD a minimal lesion of 1.6 cm. With DPET, a total of 91 lesions in 27 patients were classified as malignant. MCD without knowledge of DPET results revealed increased FDG uptake in all patients with positive DPET findings. MCD detected 72 out of 91 DPET lesions (79.1 %). With knowledge of the DPET findings, 11 additional lesions were detected (+12%). MCD missed lesions in six patients with relevance for staging in two patients. All lesions with a diameter above 18 mm were detected. Conclusion: MCD FDG imaging yielded results comparable to dedicated PET in most patients. However, a considerable number of small lesions clearly detectable with DPET were not detected by MCD alone. Therefore, MCD cannot yet replace dedicated PET in all oncological FDG studies. Further technical refinement of this new method is needed to improve image quality (e.g. attenuation correction).

Optimization of the time the chromatograph thermostats exit to a given temperature

2020 ◽  
pp. 40-45
Author(s):  
Nadezhda O. Vzduleva ◽  
Valery B. Gitlin
Keyword(s):  
Heating Rate ◽  
Entire Range ◽  
Gas Chromatograph ◽  
Heating And Cooling ◽  
Operating Temperatures ◽  
The Stability

The problems of ensuring the stability of the temperature of the chromatographic experiment carried out using a serial gas chromatograph LGH-3000 are considered. Limiting the permissible heating rate of the chromatograph thermostats does not allow a quick transition to the new conditions of the chromatographic experiment in accordance with the requirements of the technical conditions. The processes of heating and cooling the thermostat are analyzed. It is shown that the ratio of the duration of the interval equal to the sum of the durations of the heating and cooling intervals to the duration of the heating interval is inversely proportional to the temperature of the chromatographic experiment. Based on this situation, an empirical algorithm is proposed for heating the thermostat to a given temperature, which made it possible to reduce the time it takes to reach a given temperature in the entire range of operating temperatures.

From the “Judicialization of Politics” to the “Politicization of Justice” in the UK and Switzerland

2016 ◽  
Vol 6 (2) ◽  
pp. 118-135
Author(s):  
Lucia Della Torre
Keyword(s):  
General Rule ◽  
The State ◽  
The Other ◽  
Specific Field ◽  
Widespread Phenomenon ◽  
Judicialization Of Politics ◽  
The Uk ◽  
Migration Law

Not very long ago, scholars saw it fit to name a new and quite widespread phenomenon they had observed developing over the years as the “judicialization” of politics, meaning by it the expanding control of the judiciary at the expenses of the other powers of the State. Things seem yet to have begun to change, especially in Migration Law. Generally quite a marginal branch of the State's corpus iuris, this latter has already lent itself to different forms of experimentations which then, spilling over into other legislative disciplines, end up by becoming the new general rule. The new interaction between the judiciary and the executive in this specific field as it is unfolding in such countries as the UK and Switzerland may prove to be yet another example of these dynamics.

Effects of stator splitter blades on aerodynamic performance of a single-stage transonic axial compressor

2020 ◽  
Vol 14 (4) ◽  
pp. 7369-7378
Author(s):  
Ky-Quang Pham ◽  
Xuan-Truong Le ◽  
Cong-Truong Dinh
Keyword(s):  
Stokes Equations ◽  
Three Dimensional ◽  
Axial Compressor ◽  
Aerodynamic Performance ◽  
Numerical Results ◽  
Single Stage ◽  
Navier Stokes ◽  
Navier Stokes Equations ◽  
Operating Stability ◽  
Length Coverage

Splitter blades located between stator blades in a single-stage axial compressor were proposed and investigated in this work to find their effects on aerodynamic performance and operating stability. Aerodynamic performance of the compressor was evaluated using three-dimensional Reynolds-averaged Navier-Stokes equations using the k-e turbulence model with a scalable wall function. The numerical results for the typical performance parameters without stator splitter blades were validated in comparison with experimental data. The numerical results of a parametric study using four geometric parameters (chord length, coverage angle, height and position) of the stator splitter blades showed that the operational stability of the single-stage axial compressor enhances remarkably using the stator splitter blades. The splitters were effective in suppressing flow separation in the stator domain of the compressor at near-stall condition which affects considerably the aerodynamic performance of the compressor.

AN IMPROVED METHOD FOR THE ASSAY OF PROGESTERONE BY COMPETITIVE PROTEIN BINDING

1970 ◽  
Vol 63 (2) ◽  
pp. 225-241 ◽  
Author(s):  
B. D. Reeves ◽  
M. L. A. de Souza ◽  
I. E. Thompson ◽  
E. Diczfalusy
Keyword(s):  
Protein Binding ◽  
Binding Sites ◽  
Entire Range ◽  
Improved Method ◽  
Plasma Progesterone ◽  
Extraction And Purification ◽  
Corticosteroid Binding Globulin ◽  
Competitive Protein Binding ◽  
The Individual ◽  
Range Of Values

ABSTRACT An improved method for the assay of plasma progesterone by competitive protein binding is described. The improvement is based upon rigorous control of the variables, the compensation for and standardisation of interfering factors inherent in the method and the use of a human corticosteroid binding globulin, that meets the requirements for sensitivity at levels of 1.0 ng of progesterone and below. The assessment of the reliability of the individual steps in the method as well as that of the complete method is presented. The sensitivity of the method is around 0.2 ng progesterone per ml plasma. Accuracy was measured by adding progesterone in amounts ranging from 0.0 to 1.0 ng to 1.0 ml plasma. There was a linear relationship between the progesterone added and recovered throughout the entire range of values, with a coefficient of correlation (r) of 0.94. Of 52 related steroids tested, none was found which would remain associated with progesterone following extraction and purification and which would also compete with progesterone for binding sites.

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