Stability properties and periodic behavior of controlled biochemical systems

1973 ◽  
pp. 343-357 ◽  
Author(s):  
Charles Walter
Keyword(s):  
Periodic Behavior ◽  
Stability Properties ◽  
Biochemical Systems

Temporal self-organization in biochemical systems: periodic behavior vs. chaos

1983 ◽  
Vol 245 (4) ◽  
pp. R478-R483 ◽  
Author(s):  
A. Goldbeter ◽  
O. Decroly
Keyword(s):  
Narrow Range ◽  
Self Organization ◽  
Sufficient Condition ◽  
Periodic Operation ◽  
Periodic Forcing ◽  
Biochemical System ◽  
Periodic Behavior ◽  
Biochemical Systems ◽  
Stable Periodic ◽  
Parameter Values

The patterns of temporal self-organization in regulated biochemical systems are examined. Simple periodic oscillations are the most frequent type of such organization, as exemplified by glycolytic oscillations in yeast and muscle and by the periodic synthesis of adenosine 3',5'-cyclic monophosphate in Dictyostelium discoideum amoebas. These phenomena originate, respectively, from the periodic operation of the product-activated phosphofructokinase and adenylate cyclase reactions. The analysis of a model for a multiply regulated biochemical system shows more complex oscillatory phenomena, e.g., the coexistence between two stable periodic regimes for the same set of parameter values (birhythmicity) and chaos. The latter phenomenon of aperiodic oscillations occurs in a narrow range of parameter values and is much less frequent than simple or complex periodic behavior. It is suggested that a sufficient condition for the occurrence of birhythmicity and chaos in a regulated biological system subjected to a constant environment (i.e., in the absence of periodic forcing) may be the simultaneous presence and interaction of two mechanisms capable of producing oscillations.

Comparison of four commercialized biochemical systems for clinical yeast identification by colour-producing reactions

1999 ◽  
Vol 37 (1) ◽  
pp. 11-17 ◽  
Author(s):  
A. PAUGAM ◽  
M. BENCHETRIT ◽  
A. FIACRE ◽  
C. TOURTE-SCHAEFER ◽  
J. DUPOUY-CAMET
Keyword(s):  
Yeast Identification ◽  
Biochemical Systems

Partial Activation of Purified Prothrombin: Derivation of Autoprothrombin I with Use of Autoprothrombin C

1962 ◽  
Vol 07 (02) ◽  
pp. 239-248 ◽  
Author(s):  
Walter H Seegers ◽  
Edmond R Cole ◽  
Ewa Marciniak
Keyword(s):  
Calcium Ions ◽  
Platelet Factor ◽  
Stability Properties ◽  
Partial Activation ◽  
Autoprothrombin C

SummaryActivation of purified prothrombin with autoprothrombin C in the absence of calcium ions produces autoprothrombin I activity. The solubility, and stability properties of this autoprothrombin I are different from those of autoprothrombin I when obtained by activating prothrombin with calcium ions, platelet factor 3, and Ac-globulin.

A Note on Patterns of Wear Within the Tread Area

1979 ◽  
Vol 7 (1) ◽  
pp. 3-13
Author(s):  
F. C. Brenner ◽  
A. Kondo
Keyword(s):  
Content Analysis ◽  
Groove Depth ◽  
Climatic Data ◽  
Periodic Behavior ◽  
Harmonic Content ◽  
Straight Line ◽  
Data Points

Abstract Tread wear data are frequently fitted by a straight line having average groove depth as the ordinate and mileage as the abscissa. The authors have observed that the data points are not randomly scattered about the line but exist in runs of six or seven points above the line followed by the same number below the line. Attempts to correlate these cyclic deviations with climatic data failed. Harmonic content analysis of the data for each individual groove showed strong periodic behavior. Groove 1, a shoulder groove, had two important frequencies at 40 960 and 20 480 km (25 600 and 12 800 miles); Grooves 2 and 3, the inside grooves, had important frequencies at 10 240, 13 760, and 20 480 km (6400, 8600, and 12 800 miles), with Groove 4 being similar. A hypothesis is offered as a possible explanation for the phenomenon.

Сочетанные генотипы генов, кодирующих белки холецистокининергической системы и ферменты фолатного цикла в значительной степени связаны с мигренью

2020 ◽  
Author(s):  
J.E. Azimova ◽  
E.A. Klimov ◽  
E.A. Naumova ◽  
Z.G. Kokaeva ◽  
A.I. Zaitseva ◽  
...  
Keyword(s):  
Population Control ◽  
Statistical Significance ◽  
Episodic Migraine ◽  
Protective Role ◽  
Control Group ◽  
Maoa Gene ◽  
Specific Pcr ◽  
Genotype Frequencies ◽  
Biochemical Systems ◽  
Combined Genotypes

Перспективным в изучении биомаркеров мигрени может быть многолокусный анализ, в частности, анализ частот сочетанных генотипов. Цель исследования - поиск составных генетических биомаркеров индивидуальной предрасположенности к мигрени, полученных на основе полиморфизмов генов, уже показавших статистическую значимость при однолокусном ассоциативном анализе. Методика. Обследовано 155 пациентов с мигренью (104 пациента с эпизодической мигренью, 51 - с хронической мигренью), наблюдавшихся в Университетской клинике головной боли (Москва). Все пациенты - представители белой расы, жители Московского региона. Возраст пациентов - 30-50 лет. Контроль составили 365 необследованных лиц (популяционный контроль). Выявление исследуемых 22 генов (всего 31 SNP) осуществляли методом ПЦР, ПЦР-ПДРФ, аллель-специфичной ПЦР и ПЦР в реальном времени. Выявление ассоциированных с мигренью сочетанных генотипов проводили с использованием программы анализа полигенных данных APSampler v3.6. Результаты. Выявлено 8 сочетанных генотипов с высокой статистически значимой ассоциацией с мигренью (ОШ>20,0). В состав сочетанных генотипов вошли гены: CCKAR, CCKBR, COMT, MTHFR, MTR, MTRR. Так же выявлено 4 защитных сочетанных генотипа (ОШ<0,02), основным в которых является ген MAOA. Заключение. Полученные данные об ассоциированных с мигренью сочетанных генотипах указывают на значимую роль в патогенезе заболевания 2 биохимических систем: 1) холецистокининергической системы, регулирующей выброс и обратный захват дофамина, и 2) фолатного цикла, в ходе работы которого гомоцистеин метаболизируется в метионин. Результаты, полученные в данном исследовании, позволяют говорить о защитной роли аллеля VNT:R4 гена MAOA.Multilocus analysis, specifically, analysis of combined genotype frequencies may be promising in studying migraine biomarkers. The aim of the study was to search for composite genetic biomarkers, which would predict individual predisposition to migraine, obtained on the basis of gene polymorphisms that have already shown a statistical significance in a single-locus associative analysis. Methods. 155 patients with migraine aging 41.7 ± 12.5 who had been followed up at the University Clinic of Headache, Moscow, were evaluated (104 patients with episodic migraine and 51 with chronic migraine). All patients were white and residents of the Moscow region. The control group included 365 unexamined individuals (population control). Identification of The 22 genes under study (total, 31 SNPs) were identified by PCR, PCR-RFLP, allele-specific PCR, and real-time PCR. Combined genotypes associated with migraine were identified using the APSampler v3.6 software for polygenic data analysis. Results. Eight combined genotypes were identified with a highly significant association with migraine (OR> 20.0). The combined genotypes included the CCKAR, CCKBR, COMT, MTHFR, MTR, and MTRR genes. Four protective combined genotypes were also identified (OS <0.02) with the MAOA gene as the major one. Conclusion. Our data on migraine-associated combined genotypes indicate a significant role in the migraine pathogenesis of two biochemical systems, i) the cholecystokininergic system that regulates the release and reuptake of dopamine, and ii) the folate cycle, where homocysteine is metabolized to methionine. The results obtained in this study suggest a protective role of the VNT: R4 allele of the MAOA gene.

Stability properties of mean flows with turning

Tellus ◽  
1982 ◽  
Vol 34 (1) ◽  
pp. 39-49 ◽  
Author(s):  
Richard Grotjahn
Keyword(s):  
Stability Properties
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