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Results for “systems drift”

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At least 19 recordsLinked to original sources

PubMed2026

Hologenomic interactions promote the higher-order evolvability of phenotypic complexity.

Current models for evolvability and complexity generally focus on mutational and regulatory processes in the host genome alone, limiting their ability to explain the origin, inheritance, and dynamics of many phenotypes. We describe a framework treating multigenome interactions in the holobiont as a central process that impacts the genotype-phenotype map, expanding the dimensionality of mechanisms producing heritable variation, generating novel traits, and exploring adaptive trajectories. These mechanisms can promote both complex phenotypic innovation and evolutionary systems drift. Many evolutionary pathways and novelties cannot be fully understood from host data alone but require consideration of hologenomic targets of selection. We outline hypotheses and methods to quantify and evaluate their impacts as a fundamental macroevolutionary process.

cellular innovation↗

PubMed1976

A pressure- and flow-insensitive reference electrode liquid junction.

The design and construction of a pressure- and flow-insensitive reference liquid junction for use in ion concentration electrode measuring systems is described. The junction is inexpensive, is very easily and rapidly constructed, is rugged, and is adaptable to various applications. When used in a pH-measuring system, drift, pressure artifacts, and flow artifacts are negligible. The response time of the system appears to be less than 10 ms. Using the pH electrode device as described, the dissociation reaction rate constant of H2CO3 at 24 degrees C was determined to be 22 s-1.

Electrodes↗

PubMed2026

Repair and regeneration across the lifespan: an ontogenetic perspective.

The capacity for tissue repair and regeneration undergoes a profound and progressive decline across the human lifespan, representing a fundamental driver of aging and chronic disease. This review establishes a comprehensive ontogenetic framework by mapping the continuous biological transition from the flawless, scarless regenerative plasticity of embryonic development to the irreversible fibrotic scarring and organ failure characteristic of senescence. We synthesize the hierarchical collapse of reparative networks across multiple biological scales. Importantly, this ontogenetic decline should not be interpreted as a purely degenerative trajectory but rather as a dynamic systems-level reprogramming in which evolutionary trade-offs prioritize tumor suppression, immune surveillance, and reproductive fitness over long-term regenerative fidelity. Recognizing this adaptive reallocation of biological resources reframes aging not simply as failure but as a predictable recalibration of repair hierarchies. At the molecular and cellular levels, the accumulation of genomic instability, unresolvable DNA damage, and mitochondrial dysfunction gradually overwhelms intracellular quality-control mechanisms. Concurrently, epigenetic drift and chronic, low-grade systemic inflammation ("inflammaging") dismantle the stem cell niche, driving adult stem cell exhaustion and shifting wound healing away from functional tissue replacement toward maladaptive fibrosis. Furthermore, we examine divergent, organ-specific repair trajectories. By contrasting the severe regenerative restrictions of the adult central nervous system and myocardium with the persistent, yet exhaustible, resilience of the liver, we elucidate the unique intrinsic and microenvironmental barriers that impede structural and functional recovery. Finally, we evaluate the clinical paradigm shift from passive management of age-related degeneration to active restoration of tissue integrity. By integrating systemic geroscience-which addresses the global hallmarks of aging-with targeted bioengineering and in vivo epigenetic modulation, contemporary regenerative medicine seeks to recreate permissive, youthful microenvironments. Ultimately, mastering these ontogenetic principles holds unprecedented potential to reactivate endogenous repair pathways, mitigate multi-organ collapse, and significantly extend human functional healthspan.

DNA repair↗

PubMed1977

Two-stage operation for anatomical correction of transposition of the great arteries with intact interventricular septum.

To allow redevelopment of the posterior ventricle in an infant with transposition of the great arteries and intact interventricular septum, at the age of 4 weeks the pulmonary artery was banded, an aortopulmonary shunt was fashioned proximal to the band, and atrial septectomy was performed. Peak systolic posterior ventricular pressure immediately rose to systemic level (70 mm Hg.) During the next 4 months the pressure drifted back to 55 mm Hg but rose to 72 mm Hg after angiography without a rise in end-diastolic pressure. When the child was six months old anatomical correction of the transposition was successfully performed, the aorta, pulmonary, and coronary arteries being reattached to the appropriate ventricles. Debanding was performed at the same time. For the first 48 hours after operation phenoxybenzamine was given to reduce overload. At 6-month follow-up the child remained symptomless and was not on any cardiac drugs; left-ventricular function was good. This two-stage technique should widen the application of anatomical correction from a small selected group with additional defects to include most patients with transposition of the great arteries.

Aorta↗

PubMed1977

An automatically balancing isolation amplifier for the decoupling of measuring systems with high impedances.

It is theoretically shown that different conditions of coupling and grounding cause error voltages with the simultaneous use of two high-impedance measuring systems (e.g. pH electrodes). By the use of special amplifiers using optical transmission systems these error voltages are prevented. The transmission characteristics of the couplers are sensitive to changes in temperature due to the incorporation of infrared emitters in the system. An amplifying equipment with high d. c. stability was developed. The temperature drift was suppressed by the use of a special chopper stabilisation.

Electric Conductivity↗

PubMed2026

AI-driven snapshot hyperspectral imaging for on-line sorting systems in food industry: From real-time sensing to intelligent decision-making.

High-throughput food sorting requires rapid, non-destructive detection of external defects, foreign materials, and internal quality attributes in heterogeneous food matrices. Conventional scanning hyperspectral imaging may suffer from motion-induced spatial-spectral mismatches, whereas snapshot hyperspectral imaging (S-HSI) captures spectral images within a single integration time. However, its advantage is limited by trade-offs in resolution, signal-to-noise ratio (SNR), reconstruction uncertainty, and calibration stability, which are further amplified by variable tissue structure, surface reflection, moisture, and fat distribution in foods. This review critically examines artificial intelligence (AI)-driven S-HSI for on-line food sorting within a sensing-representation-decision-execution framework. Compact architectures are compared according to their physical constraints, food-sorting suitability, and ability to support mapping between spectral responses and physicochemical quality attributes. AI strategies are reviewed for spectral reconstruction, image restoration, spatial-spectral representation, band selection, uncertainty-aware decision-making, and edge implementation. AI can partially compensate for snapshot-specific limitations, but current evidence remains largely limited to laboratory or prototype studies. Future work should link system performance to food safety and quality outcomes by reporting throughput, decision latency, calibration drift, missed-detection risk, false-rejection cost, and closed-loop sorting success.

Hyperspectral Imaging↗

PubMed1976

Pathogenesis of visna. I. Sequential virologic, serologic, and pathologic studies.

A total of 56 Icelandic sheep were infected with visna virus by intracerebral injection of strain 1514 and the course of infection was followed for 12 months. Virus was isolated from more than 90 per cent of the animals, primarily from central nervous system and lymphoid tissues. However, titers of free infectious virus were minimal and virus isolation often required the use of tissue explants. All sheep raised serum-neutralizing and complement-fixing antibodies beginning 1 to 3 months after infection. Differences in neutralization titers against the infecting strain (1514) and a reference strain (796) suggested that antigenic drift might occur during prolonged infection. High cerebrospinal fluid neutralization titers in the spinal fluid indicated local antibody production in the central nervous system. Although the incidence of clinical disease during the 1st year of infection was less that 10 per cent, approximately 80 per cent of the sheep examined had central nervous system histologic lesions of variable severity, which were marked 1 month after infection with little progression during the subsequent year. There was a striking correlation between the severity of central nervous system lesions and the frequency of virus isolations from all tissues. These observations provide detailed base line data on visna infection, suggest some of the mechanisms responsible for the persistence of infection and for the slowness and irregularity of disease occurrence, and form the basis for further experiments on the role of immunologic mechanisms in the pathogenesis of this slow infection.

Animals↗

PubMed1976

Antigenic variants of influenza A virus obtained in vitro.

The aim of this study was to investigate antigenic "drift" in the haemagglutinin and neuraminidase antigens of influenza A virus in vitro under immunological pressure. Variants of the "Asian" influenza strains A/England/12/64 (H2N2) and A/Tokyo/3/67 (H2N2) were isolated in the allantois-on-shell system in the presence of homologous postinfection ferret sera. For each of these two viruses three generations of variants were isolated and characterized. It was found that the successive antigenic variants of A/Eng/12/64 did not resemble A/Tokyo/3/67. Thus it is probable that the pathway of antigenic drift in vitro was not the same as that which occurred in nature during the evolution of A/Tokyo/3/67 from A/Eng/12/64. In addition, A/Tokyo/3/67, which was the last strain to be prevalent before the A/Hong Kong subtype appeared, underwent significant antigenic drift from "junior" to "senior" variants. This finding did not support the concept that, when antigenic drift occurs, resulting in the appearence of viruses with new haemagglutinin antigen subtypes, the previously prevalent strain has no capacity for further antigenic drift. The study did not result in the production of strains that were identifiable as "bridging" viruses between the H2 and H3 haemagglutinin subtypes. The present paper includes the first report of antigenic variation in the neuraminidase antigens of influenza A viruses occurring in vitro under immunological pressure.

Antigens, Viral↗

PubMed1976

Picture quality of computed tomography.

Some limitations that impair the picture quality of computed tomography are presented. Picture grain is analyzed in detail and its relationship to different matrix sizes is demonstrated. The choices of matrix size for viewing various parts of the body are defined, and the need for higher resolution in the future is debated. Comparison is made between two scanning systems: the moving fan beam with rotation and the simple rotating fan beam. Possible artifacts in the picture caused by drift and delay in dector response are discussed.

Computers↗

PubMed1979

pH gradient electrophoresis and isoelectric focusing of lipoproteins on agarose bead thin layers.

A new method of isoelectric focusing (IEF) and pH gradient electrophoresis, using thin layers of agarose gel beads, was devised to investigate chylomicrons and very low density lipoproteins (VLDL). pH gradient stability and cathodal gradient drift were similar to those of polyacrylamide gel IEF, and linearity of gradients was maintained for 23 hr. Chylomicrons and VLDL were detectable without staining. Chylomicrons from human serum and from rat lymph migrated in this system. Rat lymph chylomicrons, obtained by ultracentrifugation, migrated in several discrete bands, and this heterogeneity or rat chylomicrons was confirmed by electron microscopic demonstration of chylomicrons in each band. This new technique has permitted the first measurement of isoelectric points of some lipoproteins in the ultracentrifuged fraction of human serum chylomicrons and the first separation of multiple discrete fractions of ultracentrifuged lymph chylomicrons.

Animals↗

PubMed1977

Circadian rhythm of synaptic excitability in rat and monkey central nervous system.

Synaptic responses in hippocampal granule cells to stimulation of their afferent fibers from the entorhinal cortex fluctuate with a 24-hour period. The phase of this cycle for rats and monkeys depends on whether the animal is naturally nocturnal or diurnal. In a rat blinded by enucleation, the rhythm persists but drifts out of phase with the rhythm of sighted controls.

Action Potentials↗

PubMed1975

Nuclear protein changes in rat hepatomas correlating with growth rate.

The nature of nuclear proteins that are soluble in 8 M urea-50 mM phosphate, pH 7.6, was compared in rat liver and Morris hepatomas, Isoelectric focusing, using carrier ampholytes for a pH gradient of 3.5 to 10, indicated that with increasing growth rate of the hepatomas there was a progressive tendency for a decrease in nonhistone nuclear proteins with isoelectric points in the range 7.5 to 8.9 and an increase in the range 5.1 to 6.7. Studies on the influence of time on the pH gradient revealed that a nonuniform drift provided a better resolution of the pH range 7.5 to 8.9 at 7 hr than at 24 hr, while the latter time for electrofocusing gave an improved resolution of the pH range 5.1 to 6.7 Polyarcylamide gel electrophoresis in a urea-acetic acid system showed that 8 M urea-50 mM phosphate; pH 7.6 extracted a small part of the histones from nuclei of both liver and hepatomas. There was less extraction of histones from the hepatoma nuclei, especially in two rapidly growing hepatomas with the most notable difference being seen in the lysine-rich H1 histone. The results suggested that in addition to qualitative or quantitative changes in nonhistone nuclear proteins in liver cancer there are alterations in the binding of histones to chromatin.

Acetates↗

PubMed1976

Development of a probe for endoureteral investigation of peristalsis by flow velocity and cross section area measurement.

A probe system for measurement of ureteric flow velocity and ureter cross section area is described. The flow velocity transducer is placed at the tip of a conventional 4-F ureteric catheter. The cross section transducer consists of two circular electrodes at an interval of 4 mm, mounted on the catheter just behind the flow velocity transducer. In vitro calibration established voltage as a function of flow velocity according to Kings law. Stability was excellent (0-point drift less than 1%/hour). Response time for flow rise was 0.02 second, and for flow fall 1.0 second. Variations of the ambient temperature at constant flow showed a margin of error in flow determination of 10 to 15%/1 degrees C temperature variation. In vitro calibration of the cross section transducer established linear correlation between voltage and tube diameter, but limited by the actual interelectrode interval. Probe displacement from tube axis gave an error of up to 10%. In vivo studies were made in anaesthetized pigs. The probe did not affect ureter peristalsis. Flow velocities ranged from 0 to 5 cm/second and ureter cross sectional areas between 0 and 0.2 cm2. Further developments in the measuring system are discussed.

Animals↗

PubMed1979

[Population genetics of the population of the northern European RSFSR. III. Demographic and genetic characteristics of two rural communities of the Pinezhskii District of the Arkhangel'sk Region].

The paper deals with the distribution of genetic markers (systems ABO, Rh, Hp, PTC) and a number of phenotyping traits (folding of arms, hand clasping, tongue rolling, right- and left-handedness, the type of ear lobe, the types of dermatoglyphics patterns) in the inhabitants of 5 villages in the Pinezhsky district of the Arkhangelsky region of the RSFSR. The data presented in this work were obtained in the course of examination of over 900 persons. Among the systems analysed there was a statistically significant deviation from Hardy-Weinberg's equlibrium. It took place in two the least villages. In one case--for ABO blood groups, in another--for Hp system. There are an interesting fact of the excess of heterozygotes 2-1 and some excess of the group 0. Statistically significant differences between villages were shown for four genetic systems. Data on migrations, distribution of gene frequencies and estimated genetic and phenotype distances between villages of the same village community and between two communities suggest, that each village community can be considered as separate subdivided population. Considering the uniformity of the environmental pressure in the region examined, the heterogeneity of the population studied is apparently associated with a random genetic drift.

Blood Group Antigens↗

PubMed1975

[Population genetics of the inhabitants of Northern European USSR. II. Blood group distribution and antropogenetic characteristics in 6 villages in Archangel Oblast].

The paper deals with the distribution of genetic markers (systems ABO, MN, Rh (D), Hp, PTC) and a number of demographic (folding of arms, hand clasping, tongue rolling, right- and left-handedness, of the type of ear lobe, of the types of dermatoglyphic patterns) in the inhabitants of 6 villages in the Mezen District of the Archangelsk Region of the RSFSR (river Peosa basin). The data presented in this work were obtained in the course of examination of over 800 persons. Differences in the interpretation of the results of generally adopted methods of statistical analysis of samples from small populations are discussed. Among the systems analysed in one third of all the cases there was a statistically significant deviation from Hardy-Weinberg's ratios. For the MN blood groups and haptoglobins this was caused by the excess of heterozygotes. The test of Hardy--Weinberg's ratios at the level of two-loci phenotypes revealed no statistically significant deviations either in separate villages or in all the villages taken together. The analysis of heterogeneity with respect to markers inherited according to Mendel's law revealed statistically significant differences between villages in all the systems except haptoglobins. A considerable heterogeneity in the distribution of family names, the frequencies of some of them varying from village to village from 0 to 90%. Statistically significant differences between villages were shown for all the anthropogenetic characters except arm folding, hand clasping and right-left-handedness. Considering the uniformity of the environmental pressure in the region examined, the heterogeneity of the population studied is apparently associated with a random genetic differentiation (genetic drift) and, possibly, with the effect of the progenitor.

Blood Group Antigens↗

PubMed2026

First detection of African swine fever in a swine farm in Taiwan.

INTRODUCTION: African swine fever (ASF) is a highly contagious, high-consequence transboundary animal disease that poses a critical threat to global swine production and agricultural economics. Since its emergence in China in 2018, ASF has spread to over 20 Asia-Pacific countries, causing significant economic disruption. While Taiwan previously detected ASF virus several times in dead pigs drifting offshore, or in illegal pork-related products brought by international tourists and inspected at airport and seaport border controls, no local domestic swine farm had tested positive before this October 2025 ASF event. However, maintaining this disease-free status requires constant vigilance against evolving regional biosecurity threats. METHODS: The first ASF detection in a domestic swine herd in Taichung City, Taiwan, reported on October 22, 2025, was triggered by abnormal alerts of the monitoring system in the rendering plant; the index farm captured a cumulative herd mortality rate of 35.2% that exceeded the predefined threshold (3% mortality daily in the nursery to finish pigs). Five finisher pigs were submitted for diagnostic evaluation, which subsequently confirmed ASFV infection via real-time PCR, pathological examination, immunohistochemistry, virus isolation, and whole-genome sequencing. RESULTS: Affected pigs showed clinical signs including wheezing, sudden death, nasal bleeding, uncoagulated blood in the nostrils, and mild hemorrhage on the skin surface of the neck, abdomen, and buttocks. Histopathological examination revealed severe multisystemic hemorrhagic lesions. Based on assay results of the P72, P54, P30, and CD2v genes, and whole-genome sequence, phylogenetic analysis confirmed that the isolate (ASFV/TWN/2025) is a genotype I/II recombinant strain, most similar to prevailing strains isolated in China and Vietnam, sharing 99.95%-99.97% and 99.92%-99.97% nucleotide similarity of whole genome sequence, respectively. DISCUSSION: Upon confirmation of the ASF case, authorities immediately implemented a nationwide swine movement standstill for 15 days to mitigate transmission risk. To date, no secondary cases have been detected. This article details the early monitoring and rapid diagnosis process of the first case of ASF infection in a farm in Taiwan, and highlights the information from this case to provide lessons for disease diagnosis and prevention in ASF-free areas.

African swine fever↗

PubMed2026

Modeling meningioma in vitro in the omics era.

Meningioma biology has been substantially clarified by recent omics-based studies, which have identified recurrent mutations, copy-number alterations, and distinct molecular subgroups. However, although these approaches have provided a valuable framework, they are inherently limited in their ability to establish direct causal relationships. The mechanistic studies are therefore indispensable for translating these molecular observations into biological understanding. Nevertheless, the mechanistic literature has often evolved in a fragmented manner, with individual pathways and model systems studied in relative isolation from the broader multi-omic landscape. In this review, we synthesize these complementary bodies of work into an integrated framework and outline a clear roadmap for future studies. We first review the historical development of established meningioma cell lines, their current molecular characterization, and the recent emergence of 3D models and organoids. Intrinsic challenges in modeling meningioma in vitro are discussed, including the difficulty of establishing immortalized cell lines from predominantly benign tumors, genetic alterations introduced during immortalization, and drift under culture conditions that differ substantially from those of the parental tumors. Next, insights from functional studies centered on these models are integrated within the molecular framework established by large-scale omics analyses. To avoid fragmentation and overemphasis on isolated findings, prior studies are organized into six categories based on major signaling pathways: Hippo, PI3K/Akt/mTOR, MAPK, Wnt/β-catenin, FOXM1, and Notch. Finally, lessons from other cancer models, including experimental approaches to chromosome-scale genomic disturbances, are considered to provide a more integrated view of meningioma biology and to highlight directions for future research.

Meningioma↗

PubMed1979

Left axis deviation: a reassessment.

This report deals with the ramifications of the concept of left axis deviation. In early life, the leftward shift of the frontal plane QRS axis is determined chiefly, if not solely, by the relative weights of the ventricles. Once adult ventricular weight ratios are reached, there is a long period of axis stability, then a gradual leftward drift of the QRS, governed principally by left anterior fascicular conduction. Thus, the normal QRS axis is age-dependent, and left axis deviation must be considered accordingly.

Adult↗