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Results for “Generation mean analysis”

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At least 19 recordsLinked to original sources

PubMed2026

Generational variation and stabilization in resynthesized allotetraploid Brassica juncea derived from diploid progenitors B. rapa and B. nigra.

BACKGROUND: Polyploidy is a major driver of plant evolution and crop improvement, generating novel variation in morphology, physiology, and agronomic traits. Brassica juncea (AABB, 2n = 36), a natural allotetraploid derived from B. rapa (AA) and B. nigra (BB), is an important oilseed and vegetable crop; however, its narrow genetic base limits further breeding gains. Resynthesized B. juncea (RBJ), developed from known progenitors, provides a tractable system to investigate polyploid stabilization, trait diversification, and generational variation. This study evaluated RBJ across nine generations (F1-S8) to elucidate generational variation in morphological, molecular, cytological, and oil content traits during progressive stabilization. RESULTS: Substantial variation was observed for key yield-related traits, including siliqua length, seeds per siliqua, and thousand-seed weight. High estimates of heritability, genotypic variance, and genetic advance indicated their potential utility in selection based improvement. Comparative analyses revealed a clear generational progression, characterized by relatively enhanced performance in early generations, increased recombination-driven variability in intermediate generations, and the partial stabilization of several traits in later generations. Generation mean analysis suggested the involvement of additive, dominance, and epistatic gene effects in trait inheritance. Molecular analysis using SSR markers confirmed the amphidiploid origin and genomic integrity of RBJ generations. Cytological assessments, pollen viability assays, and flow cytometric analysis collectively demonstrated stable chromosome numbers, improved fertility, and maintenance of ploidy stability across successive generations. CONCLUSIONS: The study provides valuable insights into the generational variation and stabilization of morphological, molecular, and oil content traits in resynthesized B. juncea. The findings suggest that variability arising from polyploidization and interspecific hybridization undergoes gradual reorganization across successive generations, leading to increased trait stabilization and more consistent expression of selected agronomic characteristics. Collectively, these results contribute to the understanding of early stabilization processes in RBJ, highlighting resynthesized polyploids as useful systems for studying variation and stabilization in allopolyploid crops.

Mustard Plant↗

PubMed1977

Enkephalin: conformational analysis by means of empirical energy calculations.

Low-energy conformations of methionine-enkephalin were generated by means of an empirical method of computation. Many compact conformations, including those containing various standard bends, were of comparable energy. However, one conformation was found to have a potential energy about 5 kcal/mol (21 X 10(3) J/mol) below that of the large group of compact conformations. In this conformation, the 3-glycyl and 4-phenylalanyl residues form a bend of type II'. The conformation is stabilized by a hydrogen bond between the OH group of the 1-tyrosine side chain and the C==O group of 3-glycine or 4-phenylalanine. The phenylalanine and methionine side chains are relatively unrestricted. The conformation is consistent with published nuclear magnetic resonance parameters--coupling constants, temperature dependence of the chemical shift, and spin-lattice relaxation times. It is likely that the molecule undergoes a conformational change when it is bound to the receptor. Leucine-enkephalin appears to have the same conformation as its methionine homolog.

Calorimetry↗

PubMed1977

Adaptive distortions in the generator potential of semicircular canal sensory afferents.

The generator potential in sensory afferents of frog crista ampullaris was extracellularly recorded from the cut end of the posterior ampullary nerve by means of suction electrodes. A servocontrolled turntable allowed suitable rotatary stimulations. The analysis of the recorded generator potential revealed a different time course from that predicted on the basis of the pendulum model. Adaptation and undershoots in the responses to velocity ramps, steps and sinusoids, were mainly responsible for the deviations, which became very evident only when fairly high acceleration rates were applied. Both adaptation and undershoots were produced presumably by the activation of an electrogenic pump, probably located in nerv terminals contacting the hair cells. In fact, the time course of the generator potential became much more consistent with the predictions from the pendulum model under treatments capable of hindering the ion pump activity.

Acceleration↗

PubMed1977

Correlation analysis of delta activity generated in cerebral hypoxia.

1. Differences in spatial and temporal characteristics between polymorphous delta activity (PDA) and "standard slow complexes" (SSCS) resulting from grave cerebral hypoxia have been demonstrated by means of digital correlation analysis and on line recording of correlograms. 2. PDA observed in the human EEG and the ECoG of dogs is characterized by the absence of periodic organization (high extinction indices of auto- and crosscorrelation functions) and absence of spatial synchronization when recorded from widely separated areas of the hemispheres (low correlation coefficients, significant and variable time shifts), with bilateral symmetry of slow waves being preserved. 3. Delta waves recorded from nucleus amygdalae, nucleus caudatus, thalamus, hypothalamus and midbrain in the dog differ from cortical PDA by a more synchronous and rhythmically arranged process. 4. During the establishment of SSC activity correlograms show a synchronous process common to all cortical aand subcortical areas characteized by very high values of correlation coefficients. 5. It is suggested that the unorganized slow wave PDA process could arise under conditions of hypoxic dysfunction of distant cortico-cortical relationships, accompanied by weak subcortical pacemaker influences. The process reflects local coexcitation of relatively limited cortical areas. The particular statistical characteristics of SSCs generated during further increase in oxygen deficit can be accounted for by simultaneous generation of responses in some subcortical areas to single volleys of impulses from a hypothetical pacemaker, accompanied by a passive wave propagation towards a cortex completetly depressed by hypoxia

Adolescent↗

PubMedDate not supplied

[Hybridologic analysis according to polygenic traits].

A method is suggested for hybridological analysis of polygenic characters based on comparing the hybrid generation's arithmetical mean components with genotypic dispersion. The method allows determining the number of genes by which parental forms differ, type and value of the gene interaction. On this basis it is possible to predict splitting off definite genotypes as well as to plan ratiis is available.

Genes↗

PubMed1979

Genetic analysis of lines selected for wing vibration in Drosophila melanogaster.

Selection for the wing vibration component of courtship in the Oregon-R stock of D. melanogaster was practiced for 44 generations. Selection was successful, indicating that there is genetic variation for the trait in the Oregon-R stock. The mean realized heritability of the trait, based on the first 11 generations of selection, was 15%. Biometrical analysis showed that there is some additive genetic variance for the trait with the possibility of some ambidirectional dominance. No maternal effects for the trait were found.

Animals↗

PubMed1979

Quantitative analysis of two-dimensional electrophoretograms.

A method for quantitative analysis of complex film density distributions in autoradiograms is described. The method is intended particularly for measuring the distribution of radioactivity among the proteins resolved by two-dimensional gel electrophoresis but should, of course, be suited to analyzing other two dimensional separations. The film density distribution is first digitized by a high speed rotating drum scanner to generate the image data array that is stored on a magnetic disk. Subsequent analysis involves: 1) data averaging, 2) detection of contours and of their locations, 3) splitting of overlapping spots, 4) conversion of film density to radioactive intensity by means of calibration films, and 5) differentiation and integration to measure the total radioactivity contained in the protein which generates a spot in the autoradiogram. The product of the analysis is a numbered contour map and a table listing coordinates and radioactivity content of each resolved spot. Coordinate transformations for comparison and matching of autoradiograms are also described. A set of utility programs print and graph the data at intermediate stages of the analysis in order to facilitate the checking of procedures and programs.

Autoradiography↗

PubMed1976

Is there evidence for subclasses of chronic lymphocytic leukemia? A study using numerical classification techniques.

Various clinical and biological parameters were analysed among 95 chronic lymphocytic leukemia patients by two numerical classification techniques in an attempt to identify natural subdivisions in the disease. For each patient, a profile made up of 47 dichotomous variables was constructed and the distance between profiles computed with equal weight for each variable. No specific cluster of patients was identified by these techniques. However limited availability of data for some laboratory tests, particularly concerning the immune system, meant that these results had to be excluded from analysis. The profiles of patients who died from leukemia during a mean follow up period of 4 years apparently do not generate a distinct group from the other profiles in spite of some clustering.

Factor Analysis, Statistical↗

PubMed1976

Genetic analysis of the centromeric heterochromatin of chromosome 2 of Drosophila melanogaster: deficiency mapping of EMS-induced lethal complementation groups.

Until recently, little was known of the genetic constitution of the heterochromatic segments of the major autosomes of Drosophila melanogaster. Our previous report described the genetic dissection of the proximal, heterochromatic region of chromosome 2 of Drosophila melanogaster by means of a series of overlapping deficiencies generated by the detachment of compound second autosomes (HILLIKER and HOLM 1975). Analysis of these deficiencies by inter se complementation, pseudo-dominance tests with proximal mutations and allelism tests with known deficiencies provided evidence for the existence of at least two loci between the centromere and the light locus in 2L and one locus in 2R between the rolled locus and the centromere. These data in conjunction with cytological observations demonstrated that light and rolled and three loci lying between them are located within the proximal heterochromatin of the second chromosome. The present report describes the further analysis of this region through the induction with ethyl methanesulphonate (EMS) of recessive lethals allelic to the 2L and 2R proximal deficiencies associated with the detachment products. Analysis of the 118 EMS-induced recessive lethals and visible mutations recovered provided evidence for seven loci in the 2L heterochromatin and six loci in the 2R heterochromatin, with multiple alleles being obtained for most sites. Of these loci, one in 2L and two in 2R fall near the heterochromatic-euchromatic junctions of 2L and 2R respectively. None of the 113 EMS lethals behaved as a deficiency, implying that the heterochromatic loci uncovered in this study represent nonrepetitive cistrons. Thus functional genetic loci are found in heterochromatin, albeit at a very low density relative to euchromatin.

Alleles↗

PubMed1977

A difference in the composition of bronchial mucus between smokers and non-smokers.

The ratio of the amount of sulphated to sialic acid mucin (Su/Si) in the mucous glands of the human tracheobronchial tree has been investigated in seven smokers and seven non-smokers. The two mucins were studied in histological sections stained by the high iron diamine/Alcian blue pH 2-5 sequence and assessed by a point-counting method. Su/Si was greater in the smokers than in the non-smokers, who were almost completely distinguished by this ratio. A decrease in the ratio with each generation of branching from the trachea down the inferior lingular bronchial segmental pathway was seen in both the smoking and non-smoking groups. Analysis of the logarithm of Su/Si showed the smoking group means to be 2-3 times that of the non-smokers at each generation, and over both groups the average decrease down successive generations was given by a factor of 0-9.

Aged↗

PubMed1979

[Response of pericruciate cortex neurons to stimulation of the medial geniculate body].

Electrical responses of 239 pericruciate neurons were studied in anaesthetized and curarized cats after stimulation of the medial geniculate body and medullary pyramids. The medial geniculate body stimulation evoked in the pericruciate neurons predominantly excitatory effects in the form of increase in the mean frequency of spike activity, generation of EPSPs and EPSPs-spike sequences. The latency analysis has shown that medial geniculate neurons have mono- and polysynaptic connections with pericruciate neurons not belonging to the pyramidal tract units.

Animals↗

PubMed1979

Relationships between hemodynamic profiles and topography of acute myocardial infarction.

Initial hemodynamics were studied in 101 patients with acute myocardial infarction complicated by shock or left heart failure. 59 had anterior myocardial infarction (AMI); 42 had inferior myocardial infarction (IMI). Data were processed by univariate analysis and correspondence analysis. AMIs and IMIs were significantly different on conduction disturbances, heart rate, left ventricular filling pressure, mean pulmonary artery pressure and right ventricular function indices. Both patients and parameters were projected on the most meaningful factorial plane generated by correspondence analysis. This two-dimensional graphical representation showed that all the information was roughly distributed along the 2 orthogonal axes defining this plane. Survivors and nonsurvivors were fairly well separated along the first factorial axis (prognostic axis) which was highly correlated with both outcome and left ventricular function parameters. AMIs and IMIs were grossly separated along the second factorial axis (topographical axis) which was rather well correlated with location and right ventricular function parameters. These studies suggest that AMI and IMI hemodynamic profiles are modulated by the presence or absence of right ventricular dysfunction. Moreover right ventricular dysfunction may be held responsible of some lack of information about left ventricular function status.

Acute Disease↗

PubMedDate not supplied

Analysis of stress patterns in the human mandible.

Replicas of a dentate human mandible were prepared in photoelastic resin material. They were positioned in a supporting frame by means of struts, representing the principal muscles of mastication. Occlusal loading was simulated, and the stresses generated within the models were examined by three-dimensional photoelastic stress analysis.

Dental Stress Analysis↗

PubMed2026

Pedagogical Efficacy of LLM-Generated Synthetic Data Versus Real-World Clinical Records: A Randomized Controlled Non-Inferiority Trial.

BACKGROUND: Expert-reviewed clinical cases generated by large language models (LLMs) may supplement case resources in medical education, but their short-term educational performance relative to real-case-derived teaching materials remains uncertain. We compared immediate post-training test performance after teaching with the two types of case materials and assessed non-inferiority against a prespecified margin. METHODS: We conducted a prospective, parallel-group, randomized non-inferiority trial. Through the Wenjuanxing online platform, participants were randomized 1:1 to learn with either real-case-derived teaching cases compiled by clinicians and reviewed by experts or AI-generated clinical cases produced by Gemini 3.0 Pro from fully de-identified matched real cases and reviewed by three senior general surgery specialists with full-professor rank. The primary outcome was the total score on an independent 10-item immediate post-training test (0-10 points), with a prespecified non-inferiority margin of -0.5 points. Secondary outcomes included the training-phase performance score, learning efficiency index, single-item mental effort rating, case realism, and case-source judgment. RESULTS: A total of 403 participants were randomized, of whom 386 were included in the modified intention-to-treat analysis: 192 in the real-case group and 194 in the AI-generated case group. The mean post-training test score was 4.95 (SD, 3.35) in the real-case group and 4.61 (SD, 3.35) in the AI-generated case group. The mean difference (AI-generated minus real-case group) was -0.335 points (95% CI, -1.006 to 0.337). Because the lower bound of the confidence interval was below the prespecified non-inferiority margin of -0.5 points, non-inferiority was not demonstrated (one-sided P = 0.314). No significant between-group differences were observed in the training-phase performance score, learning efficiency index, or single-item mental effort rating. AI-generated cases received lower realism ratings for Level 3 cases. The proportion of participants with at least one high-confidence completely incorrect response was 1.6% in the real-case group and 2.1% in the AI-generated case group. CONCLUSIONS: In this short-term, text-based online case-learning setting, no statistically significant between-group difference was observed in immediate post-training test performance; however, non-inferiority of AI-generated clinical cases relative to real-case-derived teaching materials was not demonstrated.

Humans↗

PubMed2022

Genome-scale metabolic modeling reveals increased reliance on valine catabolism in clinical isolates of Klebsiella pneumoniae.

Infections due to carbapenem-resistant Enterobacteriaceae have recently emerged as one of the most urgent threats to hospitalized patients within the United States and Europe. By far the most common etiological agent of these infections is Klebsiella pneumoniae, frequently manifesting in hospital-acquired pneumonia with a mortality rate of ~50% even with antimicrobial intervention. We performed transcriptomic analysis of data collected previously from in vitro characterization of both laboratory and clinical isolates which revealed shifts in expression of multiple master metabolic regulators across isolate types. Metabolism has been previously shown to be an effective target for antibacterial therapy, and genome-scale metabolic network reconstructions (GENREs) have provided a powerful means to accelerate identification of potential targets in silico. Combining these techniques with the transcriptome meta-analysis, we generated context-specific models of metabolism utilizing a well-curated GENRE of K. pneumoniae (iYL1228) to identify novel therapeutic targets. Functional metabolic analyses revealed that both composition and metabolic activity of clinical isolate-associated context-specific models significantly differs from laboratory isolate-associated models of the bacterium. Additionally, we identified increased catabolism of L-valine in clinical isolate-specific growth simulations. These findings warrant future studies for potential efficacy of valine transaminase inhibition as a target against K. pneumoniae infection.

Humans↗

PubMedDate not supplied

A prospective comparative clinical analysis of the first-generation knee replacements: polycentric vs. geometric knee arthroplasty.

A prospective study of 119 polycentric and 92 geometric knee replacements was performed to determine and compare the clinical effectiveness of these two prostheses. All kneex were followed for a minimum of 2 years and a mean time of 3 1/2 years (2--6 years). Data were collected using a specially designed proforma for subsequent computer analysis. Failure occurred in 11% of the polycentric and in 16% of the geometric knees. Males (8 of 47) and patients with osteoarthritic knees (22 of 68) failed most frequently. Both prostheses provided excellent relief of pain, the same degree of flexion and improvement in flexion contracture. However, walking, function, alignment, stability, muscle strength and patellar mobility varied as to the degree of improvement and the type of prosthesis. Present results with prosthetic knee replacement using a completely new operative technique can be used as a basis for comparison with other contemporary and future arthroplasty designs.

Adolescent↗

PubMed1975

Randomization and the analysis of variance.

This paper attempts to strengthen faith in randomization, first by defining it in general and second by showing how it is the fundamental means, in many experiments, of generating the probability space. It is defined by the natural structure of the experimental units (E.U.'s) not by a particular experimental design imposed on that structure. Three examples are given, with the same design but different E.U. structures and randomizations, to show that models developed from experimental designs are superficial, but that their randomization is fundamental.

Analysis of Variance↗

PubMed1978

[Intracellular regeneration and structuro-functional analysis of biological processes in normal cases and in pathology].

The author elucidates some problems in the history and the modern state in the doctrine on intracellular regenerative processes. Electron microscopic radioautography is considered as the most adequate method for studying intracellular regeneration. Certain examples are given to illustrate principally new possibilities of the structural-functional analysis of intracellular processes, normal and pathologic, studied by means of this method in view of the conception of intracellular generation. At the same time, new perspectives for further elaborating the problem of structural and functional integrity are stressed.

Animals↗