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At least 721 records · Page 40Linked to original sources
PubMedDate not supplied

[Evaluation of genetic test redundancy using a high-frequency component of the l-gram graph].

Various approaches to the estimation of DNA redundancy are compared: the Shannon entropy, the Lempel-Ziv complexity, and a new method, the computation of the low-frequency component of the l-gram graph. Although these methods are based on different ideas, they satisfy some reasonable requirements. The ability of these methods to find various kinds of repeats in genetic texts is compared. The resolution of the new method for calculation of DNA redundancy is discussed on the example of well-known repeats in the Epstein-Barr virus genome. The intrinsic discrepancy of high-frequency profile and Shannon redundancy profile were observed in some functionally significant regions of sequences being investigated.

Base Sequence↗
PubMedDate not supplied

[On connection of a graph of a gene network with qualitative modes of function].

Theoretical investigation of properties of assumed gene networks constructed from elementary units of two types, genetic elements and control links, was carried out. A test was formulated for a subclass of such networks with cyclic structure called S(n,k)-networks allowing calculation-free prediction of the network limiting properties (the presence/absence and number of stationery and/or cyclic functioning modes) from a graph of the network structure. The obtained data can be useful for constructing gene networks with predefined properties.

Genetics↗
PubMed1979

[An attempt to use graph theory for the description of demographic events].

"The possibility is discussed of using graphs to describe a sequence of demographic events such as births, marriages and deaths. Among all sequences of demographic events those with perturbations are singled out. The following perturbations are defined: childlessness, premature termination of childbearing caused by the death of the female or termination of marriage due to divorce or death of spouse, remarriage of females and pre-marital births." (SUMMARY IN ENG, RUS)

Demography↗
PubMedDate not supplied

[Graph of sodium channel states].

Four models of sodium channel are considered, only one of its state being conducting. Transitions between any two communicated states are suggested to be governed by the first order kinetics. It is shown that the model describes current responses to single step potentials as well as inactivation -- activation coupling, if its graph has a function between the conducting and inactivation states and the state filled at the hyperpolarization.

Electrophysiology↗
PubMed1999

[Application of power band graph method to the modeling and simulation of cardiovascular system].

This paper presents a computer simulation model of the cardiovascular circulation system, which describes the blood flow dynamic law in the cardiovascular system by the state equation. The model can be used in physiological study and computer-aided medical education. In this paper, the Power Band Graph (PBG) modeling method is used to realize modeling of the human circulation system and conduct a simulation study on a simplified physiological system model. The results demonstrate that the PBG method, as an understandable and unity modeling method, is quite effective and practicable and can be used widely in the field of physiological system simulation.

Computer Simulation↗
PubMedDate not supplied

Molecular descriptor based on a molar refractivity partition using Randic-type graph-theoretical invariant.

PURPOSE: Development of a novel semi-empirical descriptor (MR(chi) for molecular modelling. METHOD: The index is based on a molar refractivity partition using Randictype graph-theoretical invariant. RESULTS: This hybrid index describes not only the London dispersive forces in a ligand fragment related to the molar refractivity but also structural features of the molecule It is also applicable in Quantitative Structure-Activity Relationship (QSAR) and Quantitative Structure-Property Relationship (QSPR) studies. CONCLUSIONS: The method is convenient and can discriminate between isomers.

Chemistry, Pharmaceutical↗
PubMed2003

[Clinical application of a software for the analysis of arterial blood gases graph in 231 patients with chronic obstructive pulmonary disease].

OBJECTIVE: To evaluate the clinical significance of a computer software for the analysis of arterial blood gases graph (ABGG) in chronic obstructive pulmonary disease(COPD). METHODS: The software was developed with Win98 as the operating platform and the visual software Delphi 5.0 from Borland Company, and it was used for evaluation of the changes in arterial blood gases (ABG) of 231 COPD cases. RESULTS: (1) With the software it took only (4.7+/-0.5)s to draw and analyze an ABGG of COPD patients during oxygen inhalation; the time was much shorter than manual analysis (90.2+/-4.9)s, P<0.001. (2) During acute attack, the distributions of the arterial blood gases parameters on ABGG were as follows: 55.4% of cases in the area of insufficient ventilation and deranged gas exchange (area 5), 22.9% of cases in the area of compensated ventilation and deranged gas exchange (area 4), 21.6% of cases in the area of excessive ventilation and deranged gas exchange (area 6). (3) When the COPD patient's condition improved, the location of ABG in ABGG shifted from area 5 to area 4 or area 6. The distributions of the arterial blood gases parameters on ABGG of 106 cases on admission were significantly different from those at the time of discharge. (4) With deterioration of patient's condition, it shifted to area 5. Before death, the arterial blood gases parameters were exclusively in the area 5. CONCLUSION: The computer software for ABGG shortened the time to draw and evaluate ABG during oxygen inhalation, and it could reflect the changes in patient's condition promptly.

Aged↗
PubMed1977

[Graphs on the growth of the ice-ball using round cryoprobes at -80 degrees C and -196 degrees C (author's transl)].

Graphs and tables are shown describing the growth especially the depth of the ice-ball in tissue during freezing with round flow and massive probes (2-20 mm diameter). Thus prior to clinical application of cryosurgery the probe diameter and the time of freezing can be estimated corresponding to the size of the tumor. Results are presented for temperatures of the cooling fluid of -196 degrees C (liquid nitrogen) and -80 degrees C.

Animals↗
PubMed2004

Assembling the SARS-CoV genome -- new method based on graph theoretical approach.

Nowadays, scientists may learn a lot about the organisms studied just by analyzing their genetic material. This requires the development of methods of reading genomes with high accuracy. It has become clear that the knowledge of the changes occurring within a viral genome is indispensable for effective fighting of the pathogen. A good example is SARS-CoV, which was a cause of death of many people and frightened the entire world with its fast and hard to prevent propagation. Rapid development of sequencing methods, like shotgun sequencing or sequencing by hybridization (SBH), gives scientists a good tool for reading genomes. However, since sequencing methods can read fragments of up to 1000 bp only, methods for sequence assembling are required in order to read whole genomes. In this paper a new assembling method, based on graph theoretical approach, is presented. The method was tested on SARS-CoV and the results were compared to the outcome of other widely known methods.

Algorithms↗
PubMed2004

A novel graph-based similarity measure for 2D chemical structures.

In this paper, we propose a graph-based method to measure the similarity between chemical compounds described by 2D form. Our main idea is to measure the similarity between two compounds based on edges, nodes, and connectivity of their common subgraphs. We applied the proposed similarity measure in combination with a clustering method to more than eleven thousand compounds in the chemical compound database KEGG/LIGAND and discovered that compound clusters with highly similar structure compounds that share common names, take part in the same pathways, and have the same requirement of enzymes in reactions. Furthermore, we discovered the surprising sameness between pathway modules identified by clusters of similar structure compounds and that identified by genomic contexts, namely, operon structures of enzyme genes.

Algorithms↗
PubMed2005

Study of the prognostic value of the pregnant nutrition graph (Vallop Curve) to predict the incidence of low birth weight infants.

OBJECTIVE: To test the prognostic value of the pregnant nutrition graph (Vallop Curve). DESIGN: Prospective and comparative study. SETTING: Department of Obstetrics and Gynecology, Prangnangklao Hospital. SUBJECT: 510 cases who attended the antenatal care clinic and delivered at Prangnangklao Hospital from January 2004 to July 2004. MATERIAL AND METHOD: Height, weight and pre-pregnancy body mass index (BMI) of the women were recorded and classified BMI of each into 3 groups, low BMI (< 19.8) normal BMI (19.8 - 26.0) and high BMI (26.1 - 29.0.) The weight of the pregnant women in each gestational week was calculated as percentage of standard BMI at 21 and plotted in a Vallop Curve. The data was analyzed by using an Anova Test and Wilson Method to find association. A p-value of < 0.05 was regarded as significant. OUTCOME EVALUATION: Birth weight curve, below the 2,500 gm line and above the 2,500 gm line. RESULTS: The mean birth weight of low BMI was 2,541.70 +/- 276.89 gm. The mean birth weight of normal BMI was 3,021.30 +/- 318.61 gm. The mean birth weight of high BMI was 3,520.00 +/- 250.65 gm. There was a significant difference in weight by the Anova Test. Sensitivity was 65.6%. Specificity was 87.4%. Positive predictive value was 42.9%. Negative predictive value was 94.7%. P-value was < 0.001 at 95% confident interval by the Wilson Method. CONCLUSIONS: The Vallop Curve may be useful to predict the incidence low birth weight infants, but in the future the Vallop Curve may be changed corresponding to change of socio-economic status and also to simplify it's method of usage.

Adult↗
PubMed2005

[Correlation between the area of arterial blood gases graph and the acid-base disturbance in 92 cases with chronic obstructive pulmonary disease].

OBJECTIVE: To study the correlation between the area of arterial blood gases graph (ABGG) and the acid-base disturbance (ABD). METHODS: Using the software developed by ourselves, the results of arterial blood gases and concomitant electrolyte (K(+), Na(+), Cl(-), HCO(3)(-)) determination in 313 episodes were analyzed in 92 cases with chronic obstructive pulmonary diseases (COPD) during hospitalization, and the correlation was studied. RESULTS: (1)On admission, among 92 cases, in 9 cases the results of blood gas analysis were in the area of compensated ventilation and deranged gas exchange (area IV), in 82 cases the results were in the area of insufficient ventilation and deranged gas exchange (area V), and 1 case in the area of excessive ventilation and deranged gas exchange (area VI). There were 8 types of the ABDs, and respiratory acidosis (RAC)+metabolic alkalosis (MAL), RAC, RAC+metabolic acidosis (MAC) with increase in anion gap (AG) ranked in above order. (2)At the time of discharge, in 2 cases the distribution of ABGG was in the normal area (area I), 5 cases in the area IV, 20 cases in the area V, and 1 case in the area VI. There were 5 types of the ABDs. RAC+MAL and RAC ranked in the first two positions. (3)During hospitalization, the correlations between the area of ABGG and ABD in 313 episodes were as follows: ABD normal and MAC of AG increased in the area I; ABD normal and MAL, MAC with AG increased, RAC+MAC, respiratory alkalosis (RAL)+MAL, MAL+MAC of AG increased, RAC+MAL+MAC of AG increased and RAL+MAL+MAC of AG increased in the area IV; RAC, MAL, RAC+MAL, RAC+MAC of AG increased, MAL+MAC of AG increased, and RAC+MAL+MAC of AG increased in the area V; MAC of AG increased, RAC+MAC, RAL+MAL, MAL+MAC of AG increased, and RAL+MAL+MAC of AG increased in the area VI. No ABD occurred in the areas II and III. CONCLUSION: The correlation between ABGG and ABD can be analyzed easily and quickly and the accuracy of results is ensured by using the software.

Acid-Base Equilibrium↗
PubMedDate not supplied

[Graphical monitoring of the artificial lung ventilation. Part 1. Graphs of gas pressure and flow rate during respiration cycle. Capnogram].

Graphical monitoring of the state of the system patient-apparatus for artificial lung ventilation (MLV) provides instant and illustrative information about the state of the system, which is particularly important under conditions of resuscitation and intensive care. Graphs of time dependence of gas pressure in respiratory pathways, gas flow rate, and changes of lung volume during respiration cycle provide on-line information about ventilation mode and patient state including lungs, respiratory pathways, positive pressure at the end of exhalation, etc. These curves allow MLV efficacy to be monitored and improved. Under certain conditions the capnogram shape provides an opportunity for objective evaluation of ventilation adequacy and patient state. The shapes of the curves in the norm and various pathology are considered. This graphical information is concluded to be important for effective use of modern MLV apparatuses for intensive care and resuscitation.

Capnography↗
PubMedDate not supplied

[Connection of the tangents of the regression slope of the heart rate graph with linear and nonlinear dynamics in stationary short-time series].

The connection of the regression slope of heart rate graph (b1) with linear and nonlinear dynamics in stationary short-time series (256 points) was studied. A new index for the estimation of nonlinear dynamics in stationary short-time series was used, which is based on the correlation dimension. The results of the study indicated that the dynamics of heart rate in stationary short-time series can be represented as the sum of linear (periodic) and nonlinear (stochastic) processes. A relation of b1 with both linear and nonlinear dynamics of heart rate was found. The formulas for the calculation of absolute and relative (to the amplitude of periodic fluctuations) noise levels in heart rate dynamics were derived. A comparative analysis of nonlinear dynamics of heart rate in stationary short-time series for different functional states of humans was performed. The increase in the relative noise level in heart rate dynamics with increasing breathing frequency is related not only to a decrease in control breathing amplitude but also to an increase in the noise amplitude. The decrease in the absolute noise level for nervous excitation, fatigue, and mental stress were found. The predominance of nonlinear (stochastic) processes over linear (periodic) processes in the relaxed state was established.

Heart↗
PubMed2006

Interpreting and understanding meta-analysis graphs--a practical guide.

Ideally, clinical decision making ought to be based on the latest evidence available. However, to keep abreast with the continuously increasing number of publications in health research, a primary health care professional would need to read an insurmountable number of articles every day covered in more than 13 million references and over 4800 biomedical and health journals in Medline alone. With the view to address this challenge, the systematic review method was developed. This article provides a practical guide for appraising systematic reviews for relevance to clinical practice and interpreting meta-analysis graphs as part of quantitative systematic reviews.

Data Interpretation, Statistical↗
PubMed2005

A graph theoretical approach for analysis of protein flexibility change at protein complex formation.

Hitherto analyses of protein complexes are frequently confined to the changes in the interface of the protein subunits undergoing interaction, while the holistic picture of the protein monomers' structure transformation, or the pervasive rigidity adopted by the newly formed complex are most often than not improperly evaluated in spite of the multiple and deep insights that they can yield about the interaction process itself at the molecular level, or at the higher level of genomic functional analyses for which relevant systems biological information can be obtained. To address this aspect of protein-protein interaction we propose in this work a newly developed algorithm that is based on graph theoretical instances and makes possible the evaluation of the changes in the flexibility of the interacting molecules and the rigidity adopted at complex formation. Since one can also figure out the opposite process, i.e. that in which the complex decomposes into its constituent subunits, each of which may accomplish another vital role in the organism, the methodology proposed here is also able to address such problem. The algorithm we propose performs a rigidity and/or flexibility evaluation of every node (atom) on the network constituted by the entire set of intra and inter-molecular inter-atomic interactions. Comparison of flexible or rigid molecular regions or domains within the complex with those in the respective isolated monomers leads to quantification of the loss (or gain) in the number of degrees of freedom at complex formation and their effects on protein complex formation mechanisms. This index is also valuable in the identification of collective motions within the protein that may play a critical role in the process of complex formation, and the influences they may have in the behavior and function of the complex (as well as the subunits constituting it) within the organism. Furthermore, the methodology, embedded in protein docking algorithms allows the development of a framework for categorizing and ranking decoys output by broadly used grid scoring type algorithms, one of which is the system for protein-protein interaction system MIAX that has been under continuous development in recent years.

Animals↗
PubMed1990

Analysis of multiscale biochemical systems: graph methods.

The applicability of usual biochemical modelling by ordinary differential equations is restricted if some of the metabolite concentrations leave the range of observability during the time span of interest. Therefore, a method is needed for testing whether the solution of a differential equation system remains comparable with given reference concentrations, which depend on the conditions of measurement. In the present paper, such a method based on graph theory and non-standard analysis is developed for the special case of networks of monomolecular reactions endowed with linear kinetics.

Algorithms↗
PubMed1990

Value of scatter-graphs for the assessment of ECG computer measurement results.

A new method is presented, different from usual methods, for the discussion of the results of computer ECG measurement programs, based on a new graphical evaluation method. The proposed "scatter-graphs" both highlight the main program results and facilitate the comparison between various wave-recognition algorithms. They allow the distinction between the reliability of an algorithm, which is its capacity to provide a maximum of measurements with a minimum amount of errors, and its precision, i.e., the standard deviation of the differences between its point estimates and the reference. The method proves to be a powerful tool for the discussion of individual, as well as the median program results in CSE Measurement Study. It allows to highlight limitations induced in performance assessment by the variability of the reference itself, and to state that the median program is at least as close to the "Gold Standard" as the median of the referees.

Algorithms↗