The controllability of cardiac rhythm in elderly

Introduction: Recent reports have shown that rare fluctuations in cardiac cycles are ‘forgotten’ quickly in healthy individuals and it is possible to quantify the “memory length” of a physiological time-series using an inverse statistical approach. Methods: In the present study, we assessed the effect of aging on memory length in cardiac rhythm. Results: There was a longer memory length in cardiac time-series of elderly subjects in comparison with younger adults for both decelerating and accelerating rare fluctuations in cardiac rhythm. Conclusion: The increased memory length of the cardiac time-series in elderly subjects may indicate reduced controllability of cardiovascular regulatory system

Modifying the transition temperature, 120 K ≤ Tc ≤ 1150 K, of amorphous Fe90−xCoxSc10 with simultaneous alteration of fluctuation of exchange integral up to zero

Amorphous (a-) Fe90−xCoxSc10 alloys have been produced by rapid quenching from the melt. The Curie temperature, TC, was determined using both mean field theory and Landau’s theory of second-order phase transitions in zero and non-zero external fields. The dependence of TC on the atomic spacing can be explained by the empirical Bethe-Slater curve. The value of TC of a- Fe5Co85Sc10, determined by the above theoretical approaches is 1150 K, which is the highest TC ever measured for amorphous alloys. The flattening of the measured normalized magnetization, M(T)/M(0), as a function of the reduced temperature, T/TC, is explained within the framework of the Handrich- Kobe model. According to this model the fluctuation of the exchange integral is the main reason for the flattening of M(T)/M(0). In the case of a-Fe90Sc10 without Co, however, the fluctuation of the exchange integral is dominant only at zero external field, Bex = 0. At Bex = 9 T, however, the fluctuation of the exchange integral has no conspicuous effect on the reduction of the magnetization. It is shown that at Bex = 9 T the frozen magnetic clusters control the behaviour of the reduced magnetization as function of T/TC. In contrast to other ferromagnetic alloys, where the flattening of M(T)/M(0) is characteristic for an amorphous structure, the a- Fe5Co85Sc10 does not exhibit any trace of the fluctuation of the exchange integral

Exact Shock Profile for the ASEP with Sublattice-Parallel Update

We analytically study the one-dimensional Asymmetric Simple Exclusion Process (ASEP) with open boundaries under sublattice-parallel updating scheme. We investigate the stationary state properties of this model conditioned on finding a given particle number in the system. Recent numerical investigations have shown that the model possesses three different phases in this case. Using a matrix product method we calculate both exact canonical partition function and also density profiles of the particles in each phase. Application of the Yang-Lee theory reveals that the model undergoes two second-order phase transitions at critical points. These results confirm the correctness of our previous numerical studies.Comment: 12 pages, 3 figures, accepted for publication in Journal of Physics

Comparative Study of the Antioxidant Activity of Two Popular Green Tea Beverages Available in the Local Market of Saudi Arabia

Abstract Antioxidants have numerous applications due to their multiple roles in diminishing harmful effects of oxidative stress. The objective of this work was to highlight the importance of green tea by evaluating the antioxidant activity of the most popular green tea brands in Saudi Arabia, Lipton and Rabea. To our knowledge, no studies have so far been done to estimate the antioxidant activity of these brands. To determine the antioxidant activities of these two brands, 10 mg/ml of each brand was extracted and their total phenolic content (TPC), 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity, hydrogen peroxide scavenging activity, ferric reducing power and ferrous ion chelating effect were measured. The TPC of Lipton tea was 678.7 µg of gallic acid equivalents (GAE)/10mg, whereas in Rabea tea, the TPC was 647.1 µg GAE/10mg. The presence study indicated that there were no significant differences in total phenolic contents and the percentage inhibition as shown in DPPH and H 2 O 2 assays among Lipton and Rabea green teas. Moreover, it was found that all assays have exhibited high antioxidant activity in both green teas. In conclusion, our study showed evidence for evenness and stability of the antioxidant activity of the two commercial green teas available in the markets of Saudi Arabia. Continued researches are needed to further the current knowledge on the health-promoting effects of this popular beverage using different supplements by different mechanisms

The contributions of citizen science to SDG monitoring and reporting on marine plastics

The accumulation of plastic litter in marine environments is a major environmental challenge along with the difficulties in their measurement because of the massive size of the oceans and vast circulation of plastic litter, which is being addressed as part of the United Nations (UN) Sustainable Development Goals (SDGs). Citizen science, public participation in scientific research and knowledge production, represents a potential source of data for SDG monitoring and reporting of marine plastic litter, yet there has been no evidence of its use to date. Here, we show how Ghana has become the first country to integrate existing citizen science data on marine plastic litter in their official monitoring and reporting of SDG indicator 14.1.1b for the years 2016–2020, which has also helped to bridge local data collection efforts with global monitoring processes and policy agendas by leveraging the SDG framework. The results have been used in Ghana’s 2022 Voluntary National Review of the SDGs, and reported on the UN SDG Global Database, as well as helping to inform relevant policies in Ghana. In addition, here, we present a pathway that can be adopted by the relevant government authorities in other countries that have an interest in following a similar citizen science data validation and reporting process for this indicator and potentially others

Electrospinning piezoelectric fibers for biocompatible devices

The field of nanotechnology has been gaining great success due to its potential in developing new generations of nanoscale materials with unprecedented properties and enhanced biological responses. This is particularly exciting using nanofibers, as their mechanical and topographic characteristics can approach those found in naturally occurring biological materials. Electrospinning is a key technique to manufacture ultrafine fibers and fiber meshes with multifunctional features, such as piezoelectricity, to be available on a smaller length scale, thus comparable to subcellular scale, which makes their use increasingly appealing for biomedical applications. These include biocompatible fiber-based devices as smart scaffolds, biosensors, energy harvesters, and nanogenerators for the human body. This paper provides a comprehensive review of current studies focused on the fabrication of ultrafine polymeric and ceramic piezoelectric fibers specifically designed for, or with the potential to be translated toward, biomedical applications. It provides an applicative and technical overview of the biocompatible piezoelectric fibers, with actual and potential applications, an understanding of the electrospinning process, and the properties of nanostructured fibrous materials, including the available modeling approaches. Ultimately, this review aims at enabling a future vision on the impact of these nanomaterials as stimuli-responsive devices in the human body

Scopolamine Administration Modulates Muscarinic, Nicotinic and NMDA Receptor Systems

Studies on the effect of scopolamine on memory are abundant but so far only regulation of the muscarinic receptor (M1) has been reported. We hypothesized that levels of other cholinergic brain receptors as the nicotinic receptors and the N-methyl-D-aspartate (NMDA) receptor, known to be involved in memory formation, would be modified by scopolamine administration