About 4-day Rhythm of Proliferative Activity of Fibroblast-like Cell Cultures Depends on the Environmental Factor

A study of the 4-day rhythm of the proliferative activity of the embryonic fibroblast-like cells in the logarithmic growth phase was carried out. It was shown that in cell cultures obtained on different days from embryos of different ages, the phase of the 4-day rhythm coincides. In vitro the maxima of the proliferative activity were consistent with the minima of the motor activity of mice. Freezing the culture for 2 or 6 days does not cause a shift in the phase of the 4-day rhythm of cell proliferative activity compare with the unfreezing culture. That indicates the existence of an external synchronizer, which determines the 4-day infradian rhythm of the proliferative activity of embryonic cells. Then we daily thawed samples of single L-929 culture of mice fibroblast-like cells for 22 and 17 days and researched the dynamics of its proliferative activity. We also showed 4-day rhythm of the simultaneous increase in the number of cells for all thawed samples. Taking into account that deep freezing of a culture leads to the cessation of all life processes, the fact we obtained indicates an exogenous mechanism of the formation of about a 4-day rhythm of the proliferative activity of cell culture.

Odd entanglement entropy and logarithmic negativity for thermofield double states

We investigate the time evolution of odd entanglement entropy (OEE) and logarithmic negativity (LN) for the thermofield double (TFD) states in free scalar quantum field theories using the covariance matrix approach. To have mixed states, we choose non-complementary subsystems, either adjacent or disjoint intervals on each side of the TFD. We find that the time evolution pattern of OEE is a linear growth followed by saturation. On a circular lattice, for longer times the finite size effect demonstrates itself as oscillatory behavior. In the limit of vanishing mass, for a subsystem containing a single degree of freedom on each side of the TFD, we analytically find the effect of zero-mode on the time evolution of OEE which leads to logarithmic growth in the intermediate times. Moreover, for adjacent intervals we find that the LN is zero for times t < β/2 (half of the inverse temperature) and after that, it begins to grow linearly. For disjoint intervals at fixed temperature, the vanishing of LN is observed for times t < d/2 (half of the distance between intervals). We also find a similar delay to see linear growth of ∆S = SOEE− SEE. All these results show that the dynamics of these measures are consistent with the quasi-particle picture, of course apart from the logarithmic growth.

Fibonacci Sequence-related Phenomenon During Chondrocyte Proliferation of the Gottingen Pig Knee Tibial Plateau

Background The aim of our study was to observe the quantitative changes in tibial plateau chondrocytes in the proliferation process from normal Gottingen pigs in vitro and compare them with the Fibonacci sequence.Methods Chondrocytes from normal Gottingen pig tibial plateau cartilage were isolated and cultured to the third generation, and the number of chondrocytes was measured to determine whether the chondrocyte growth was at the logarithmic growth phase. Chondrocytes were added to cell culture bottles at very a low density to allow full separation and allow each chondrocyte to grow as independently as possible. Thirty single chondrocytes were selected, and the number of chondrocyte colonies were observed and recorded every day. Results Among the 30 chondrocyte colonies, the changes in the numbers of 16 chondrocyte colonies were 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 144, 233, 377, 610, and 987, which conformed to the numbers of the Fibonacci sequence.The number of other chondrocyte colonies was lower than corresponding numbers of the Fibonacci sequence at the same time point.Conclusion The numbers of normal Gottingen pig tibial plateau chondrocytes during the proliferation process were in line with the numbers of the Fibonacci sequence.Alignment to the Fibonacci sequence may be the fastest way for changes in the numbers of normal chondrocytes during the proliferation process in vitro.

Effect of control measures on the pattern of COVID-19 Epidemics in Japan

Background COVID-19 has spread worldwide since its emergence in 2019. In contrast to many other countries with epidemics, Japan differed in that it avoided lockdowns and instead asked people for self-control. A travel campaign was conducted with a sizable budget, but the number of PCR tests was severely limited. These choices may have influenced the course of the epidemic. Methods The increase or decrease in the classes of SARS-CoV-2 variants was estimated by analyzing the published sequences with an objective multivariate analysis. This approach observes the samples in multiple directions, digesting complex differences into simpler forms. The results were compared over time with the number of confirmed cases, PCR tests, and overseas visitors. The kinetics of infection were analyzed using the logarithmic growth rate. Results The declared states of emergency failed to alter the movement of the growth rate. Three epidemic peaks were caused by domestically mutated variants. In other countries, there are few cases in which multiple variants have peaked. However, due to the relaxation of immigration restrictions, several infective variants have been imported from abroad and are currently competing for expansion, creating the fourth peak. By April 2021, these foreign variants exceeded 80%. The chaotic situation in Japan will continue for some time, in part because no effort has been made to identify asymptomatic carriers, and details of the vaccination program are undecided.

COVID-19 epidemics monitored through the logarithmic growth rate and SIR model

Background: The SIR model is often used to analyse and forecast the expansion of an epidemic. In this model, the number of patients exponentially increases and decreases, resulting in two phases. Therefore, in these phases, the logarithm of infectious patients changes at a constant rate, the logarithmic growth rate K. However, in the case of the coronavirus disease 2019 (COVID19) epidemic, K never remains constant but increases and decreases linearly; therefore, the SIR model does not fit that seen in reality. We would like to clarify the cause of this phenomenon and predict the occurrence of COVID19 epidemics. Methods: We simulated a situation in which smaller epidemics were repeated with short time intervals. The results were compared with the epidemic data from 279 countries and regions. Results: In the simulations, the K values increased and decreased linearly, similar to the real data. Because the previous peak covered the initial increase in the epidemic, K did not increase as much as expected; rather, the difference in the basic reproduction number R0 appeared in the slope of increasing K. Additionally, the mean infectious time τ appeared in the negative peaks of K. By using the R0 and τ estimated from the changes in K, changes in the number of patients could be approximated using the SIR model. This supports the appropriateness of the model for evaluating COVID-19 epidemics. By using the model, the distributions of the parameters were identified. On average, an epidemic started every eleven days in a country. The worldwide mean R0 was 2.9; however, this value showed an exponential character and could thus increase explosively. In addition, the average τ was 12 days; this is not the native value but represents a shortened period because of the isolation of patients. As τ represents the half-life, the infectious time varies among patients; hence, prior testing should be performed before isolation is lifted. The changes in K represented the state of epidemics and were several weeks to a month ahead of the changes in the number of confirmed cases. In the actual data, when K was positive on consecutive days, the number of patients increased a few weeks later. In addition, if the negative peaks of K could not be reduced to as small as 0.1, the number of patients remained high. Thus, the number of K-positive days and mean infectious time had a clear correlation with the total number of patients. In such cases, mortality, which was lognormally distributed, with a mean of 1.7%, increased. To control the epidemic, it is important to observe K daily, not to allow K to remain positive continuously, and to terminate a peak with a series of K-negative days. To do this, it was necessary to shorten τ by finding and isolating a patient earlier. The effectiveness of the countermeasures is apparent in τ. The effect of vaccination, in terms of controlling the epidemic, was limited.

Thorsmoerkia curvula gen. et spec. nov. (Trebouxiophyceae, Chlorophyta), a semi-terrestrial microalga from Iceland exhibits high levels of unsaturated fatty acids

A terrestrial green alga was isolated at Iceland, and the strain (SAG 2627) was described for its morphology and phylogenetic position and tested for biotechnological capabilities. Cells had a distinctly curved, crescent shape with conical poles and a single parietal chloroplast. Phylogenetic analyses of 18S rDNA and rbcL markers placed the strain into the Trebouxiophyceae (Chlorophyta). The alga turned out to belong to an independent lineage without an obvious sister group within the Trebouxiophyceae. Based on morphological and phylogenetic data, the strain was described as a new genus and species, Thorsmoerkia curvula gen. et sp. nov. Biomass was generated in column reactors and subsequently screened for promising metabolites. Growth was optimized by pH-regulated, episodic CO2 supplement during the logarithmic growth-phase, and half of the biomass was thereafter exposed to nitrogen and phosphate depletion. The biomass yield reached up to 53.5 mg L−1 day−1. Fatty acid (FA) production peaked at 24 mg L−1 day−1 and up to 83% of all FAs were unsaturated. At the end of the log phase, approximately 45% of dry mass were lipids, including eicosapentaenoic acid. Carotenoid production reached up to 2.94 mg L−1 day−1 but it was halted during the stress phase. The N-linked glycans of glycoproteins were assessed to reveal chemotaxonomic patterns. The study demonstrated that new microalgae can be found at Iceland, potentially suitable for applied purposes. The advantage of T. curvula is its robustness and that significant amounts of lipids are already accumulated during log phase, making a subsequent stress exposure dispensable.

Prevalence and Expression of Genes of Type II Antitoxin Toxin Systems in Clinical Isolates of Methicillin-Resistant Staphylococcus aureus

Objectives: Antibiotic resistance of bacteria has been increasing in recent years and reports indicate that some bacterial strains are even resistant to the last treatment line. The survey of MazEF antitoxin-toxin genes in 84 strain of MRSA and and the antimicrobial effect of supernatants on the logarithmic growth stage of the bacteria. Methods: In this study, 84 strains of MRSA were collected. The patients included 48 males and 36 females with a mean age of 39 years. The primers for Staphylococcus aureus type II antitoxin genes were designed. In the first step, using the mecA primer and PCR, the strains were genetically examined to confirm methicillin-resistant Staphylococcus aureus. In the next step, the frequency of MazEF antitoxin-toxin genes was examined. Results: All strains of methicillin-resistant Staphylococcus aureus had the F maz gene except one. The highest antibiotic resistance was related to the strains isolated from the wound and the lowest resistance was related to the strains isolated from the urine. the effect of the supernatant obtained in the death phase of Staphylococcus aureus was assessed and the antimicrobial effect of these supernatants on the logarithmic growth stage of the bacteria was measured. Conclusion: since previous studies showed the antimicrobial effect of this supernatant on many other bacteria, a type II system was suspected that was confirmed by the results.

Subsystem complexity after a local quantum quench

We study the temporal evolution of the circuit complexity after the local quench where two harmonic chains are suddenly joined, choosing the initial state as the reference state. We discuss numerical results for the complexity for the entire chain and the subsystem complexity for a block of consecutive sites, obtained by exploiting the Fisher information geometry of the covariance matrices. The qualitative behaviour of the temporal evolutions of the subsystem complexity depends on whether the joining point is inside the subsystem. The revivals and a logarithmic growth observed during these temporal evolutions are discussed. When the joining point is outside the subsystem, the temporal evolutions of the subsystem complexity and of the corresponding entanglement entropy are qualitatively similar.