Microfluidic-Assisted Human Cancer Cells Culturing Platform for Space Biology Applications.

In the paper, the lab-on-chip platform applicable for the long-term cultivation of human cancer cells, as a solution meeting the demands of the CubeSat biological missions, is presented. For the first time, the selected cancer cell lines-UM-UC-3 and RT 112 were cultured on-chip for up to 50 days. The investigation was carried out in stationary conditions (without medium microflow) in ambient temperature and utilizing the microflow perfusion system in the incubation chamber assuring typical cultivation atmosphere (37 °C). All the experiments were performed to imitate the conditions that are provided before the biological mission starts (waiting for the rocket launch) and when the actual experiment is initialized on a CubeSat board in space microgravity. The results of the tests showed appropriate performance of the lab-on-chip platform, especially in the context of material and technological biocompatibility. Cultured cells were characterized by adequate morphology-high attachment rate and visible signs of proliferation in each of the experimental stage. These results are a good basis for further tests of the lab-on-chip platform in both terrestrial and space conditions. At the end of the manuscript, the authors provide some considerations regarding a potential 3-Unit CubeSat biological mission launched with Virgin Orbit company. The lab-on-chip platform was modelled to fit a 2-Unit autonomous laboratory payload.

Does routine clinical practice reproduce the outcome of large prospective trials? The analysis of institutional database on patients with limited-disease small-cell lung cancer.

We performed the analysis of database on 409 patients with LD-SCLC to evaluate as to what extent the clinical outcome of large prospective trials was reproduced in routine practice. The analysis has shown that the hazard rate of death in the absence of prophylactic cranial irradiation (PCI) adjusted for the effects of confounding factors, appeared larger than that reported in the trials on PCI in LD-SCLC, and was comparable to that estimated for extensive disease. Less intense routine staging procedures, compared to the trial settings, contributed for such outcome. Hyperfractionated thoracic radiotherapy provided survival advantage similar to that reported in the literature.

Point field emission electron source with a magnetically focused electron beam.

This paper presents a field emitter in the form of a silicon tip covered with a layer of carbon nanotubes. The emitted beam is focused with a set of two electrostatic lenses and - which is novelty in such structures - with a magnetic field. The presented approach gave very promising results. The field emitter was able to provide a high emission current (about 50 µA) and a beam with a small and homogeneous spot. Such electron sources are necessary components of many miniature MEMS and nanoelectronics devices. The presented source is dedicated especially for the use in currently developed MEMS X-ray sources and MEMS electron microscopes.

Leveraging spiking neural networks for topic modeling.

This article investigates the application of spiking neural networks (SNNs) to the problem of topic modeling (TM): the identification of significant groups of words that represent human-understandable topics in large sets of documents. Our research is based on the hypothesis that an SNN that implements the Hebbian learning paradigm is capable of becoming specialized in the detection of statistically significant word patterns in the presence of adequately tailored sequential input. To support this hypothesis, we propose a novel spiking topic model (STM) that transforms text into a sequence of spikes and uses that sequence to train single-layer SNNs. In STM, each SNN neuron represents one topic, and each of the neuron's weights corresponds to one word. STM synaptic connections are modified according to spike-timing-dependent plasticity; after training, the neurons' strongest weights are interpreted as the words that represent topics. We compare the performance of STM with four other TM methods Latent Dirichlet Allocation (LDA), Biterm Topic Model (BTM), Embedding Topic Model (ETM) and BERTopic on three datasets: 20Newsgroups, BBC news, and AG news. The results demonstrate that STM can discover high-quality topics and successfully compete with comparative classical methods. This sheds new light on the possibility of the adaptation of SNN models in unsupervised natural language processing.

A research synthesis on successful educational practices and student outcomes for physical education in schools.

Although successful educational practices (SEPs) in higher education institutions have well-established student outcomes, the vast majority do not meet physical education standards in schools. Despite the promising nature of policy initiatives supporting schools, there is scant evidence of how these SEPs affect student outcomes. This review aimed to determine the status of the literature and the type of evidence regarding school SEPs. Several studies have demonstrated that these SEPs contribute directly or indirectly to improving student outcomes. Three objectives were examined and synthesized in our review of SEP research findings. The first goal is to identify different types of impacts on students in schools. The second goal is to provide educators, principals, and policymakers with a unified and comprehensive framework. Lastly, we provide suggestions for future SEP research. The review identified 45 studies that met our inclusion criteria. Our reviewed studies documented impacts on the individual level. It encompasses both students' instrumental abilities and their sense of self-esteem and motivation. Secondly, improving interpersonal relationships, reducing conflict, and increasing group cohesion are important components at the group level. Finally, there are factors at the community level, including absenteeism reduction, parental involvement, and changes in attitudes toward school. Current research supports the effectiveness of successful school practices. It stresses the importance of implementing policies to maximize student outcomes. Finally, the review concludes by discussing findings implications and future research directions.

Spike-Timing-Dependent Plasticity With Activation-Dependent Scaling for Receptive Fields Development.

Spike-timing-dependent plasticity (STDP) is one of the most popular and deeply biologically motivated forms of unsupervised Hebbian-type learning. In this article, we propose a variant of STDP extended by an additional activation-dependent scale factor. The consequent learning rule is an efficient algorithm, which is simple to implement and applicable to spiking neural networks (SNNs). It is demonstrated that the proposed plasticity mechanism combined with competitive learning can serve as an effective mechanism for the unsupervised development of receptive fields (RFs). Furthermore, the relationship between synaptic scaling and lateral inhibition is explored in the context of the successful development of RFs. Specifically, we demonstrate that maintaining a high level of synaptic scaling followed by its rapid increase is crucial for the development of neuronal mechanisms of selectivity. The strength of the proposed solution is assessed in classification tasks performed on the Modified National Institute of Standards and Technology (MNIST) data set with an accuracy level of 94.65% (a single network) and 95.17% (a network committee)-comparable to the state-of-the-art results of single-layer SNN architectures trained in an unsupervised manner. Furthermore, the training process leads to sparse data representation and the developed RFs have the potential to serve as local feature detectors in multilayered spiking networks. We also prove theoretically that when applied to linear Poisson neurons, our rule conserves total synaptic strength, guaranteeing the convergence of the learning process.

A comparison of muscle activity of the dominant and non-dominant side of the body during low versus high loaded bench press exercise performed to muscular failure.

The main aim of the study was to compare the peak surface electromyography (sEMG) amplitude of muscles during low and high loaded bench press exercises performed to muscular failure on the dominant and non-dominant body side. Ten resistance-trained healthy males with at least six-year experience in resistance training (27.7 ± 5.6 years, 81.1 ± 5.8 kg and 175.3 ± 5.2 cm, bench press one-repetition maximum [1RM] = 98.9 ± 7.1 kg) performed the bench press at 50% and at 90%1RM. The differences in peak sEMG amplitude between body-sides and the external loads were recorded for the pectoralis major (PM), anterior deltoid (AD), and the long head of the triceps brachii (TB) during each attempt. A two-way repeated-measures ANOVAs revealed statistically significant main effect of side for AD (p < 0.001) and TB (p < 0.001) but not for PM (p = 0.168) and a significant main effect of load for TB (p < 0.001) but not for AD and PM (p = 0.229; p = 0.072; respectively). The post-hoc analysis for the main effect of side showed significantly higher peak sEMG amplitude for the dominant side compared to the non-dominant side for AD and TB at 50%1RM and 90%1RM (p < 0.001; all) with no statistically significant differences for PM (p = 0.187; p = 0.155; both loads). The post-hoc analysis for the main effect of load for TB revealed a significantly higher peak sEMG amplitude at 90%1RM compared to the 50%1RM (p = 0.009). The obtained results indicate that regardless of the external load, the peak sEMG activity of the AD, PM, and TB during the bench press exercise performed to muscular failure was higher on the dominant body-side.

Corrigendum: Contrast Tempo of Movement and Its Effect on Power Output and Bar Velocity During Resistance Exercise.

[This corrects the article DOI: 10.3389/fphys.2020.629199.].

Contrast Tempo of Movement and Its Effect on Power Output and Bar Velocity During Resistance Exercise.

In this study, we examined the impact of contrast movement tempo (fast vs. slow) on power output and bar velocity during the bench press exercise. Ten healthy men (age = 26.9 ± 4.1 years; body mass = 90.5 ± 10.3 kg; bench press 1RM = 136.8 ± 27.7 kg) with significant experience in resistance training (9.4 ± 5.6 years) performed the bench press exercise under three conditions: with an explosive tempo of movement in each of three repetitions (E/E/E = explosive, explosive, explosive); with a slow tempo of movement in the first repetition and an explosive tempo in the next two repetitions (S/E/E = slow, explosive, explosive); and with a slow tempo of movement in the first two repetitions and an explosive tempo in the last repetition (S/S/E = slow, slow, explosive). The slow repetitions were performed with a 5/0/5/0 (eccentric/isometric/concentric/isometric) movement tempo, while the explosive repetitions were performed with an X/0/X/0 (X- maximal speed of movement) movement tempo. During each experimental session, the participants performed one set of three repetitions at 60%1RM. The two-way repeated measures ANOVA showed a statistically significant interaction effect for peak power output (PP; p = 0.03; η 2 = 0.26) and for peak bar velocity (PV; p = 0.04; η 2 = 0.24). Futhermore there was a statistically significant main effect of condition for PP (p = 0.04; η 2 = 0.30) and PV (p = 0.02; η 2 = 0.35). The post hoc analysis for interaction revealed that PP was significantly higher in the 2nd and 3rd repetition for E/E/E compared with the S/S/E (p < 0.01 for both) and significantly higher in the 2nd repetition for the S/E/E compared with S/S/E (p < 0.01). The post hoc analysis for interaction revealed that PV was significantly higher in the 2nd and 3rd repetition for E/E/E compared with the S/S/E (p < 0.01 for both), and significantly higher in the 2nd repetition for the S/E/E compared with the S/S/E (p < 0.01). The post hoc analysis for main effect of condition revealed that PP and PV was significantly higher for the E/E/E compared to the S/S/E (p = 0.04; p = 0.02; respectively). The main finding of this study was that different distribution of movement tempo during a set has a significant impact on power output and bar velocity in the bench press exercise at 60%1RM. However, the use of one slow repetition at the beginning of a set does not decrease the level of power output in the third repetition of that set.