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Topic Review
Acoustic Emission Spectroscopy
Acoustic emission (AE) spectroscopy has become the method of choice in many fieldsbecause it is highly sensitive. For example, the AE system constructed by the Vallen company, Germany, has a sampling rate that can reach up to 10 MHz, an arrival time resolution of 100 ns, and an energy resolution of 1.8 × 10−18V2s (i.e., in the attojoule regime, aJ) referred to sensor signal at 34 dB preamplifier gain.
  • 1.1K
  • 28 Oct 2021
Topic Review
Simple Models of Pulmonary Artifacts
Nowadays, the diagnostic value of the artefactual information provided by lung ultrasound images is widely recognized by physicians. In particular, the existence of a correlation between the visual characteristics of the vertical artifacts, which arise from the pleura line, and the genesis (pneumogenic or cardiogenic) of a pulmonary disorder is commonly accepted. However, the link between these visual characteristics and the causes which determine them is still unclear. In order to derive further information from the visual inspection of the vertical artifacts the mechanisms which control the artifact formation must be identified. The link between the visual characteristics of the vertical artifacts (the observed effect) and the distribution of the aerated spaces at the pleural level (the cause) must be addressed. Plausible mechanisms should be illustrated through experimental results and through the theoretical analysis of simple models.
  • 511
  • 27 Oct 2021
Topic Review
Ceramics, Glass and Glass-Ceramics for Personal Radiation Detectors
Different types of ceramics and glass have been extensively investigated due to their application in brachytherapy, radiotherapy, nuclear medicine diagnosis, radioisotope power systems, radiation processing of food, geological and archaeological dating methods. The comparison of the physico-chemical properties shows that glassy materials could be a promising alternative for dosimetry purposes.
  • 841
  • 27 Oct 2021
Topic Review
Interactions between Atmospheric Oxygen and MoS2 Crystals
MoS2 belongs to a class of transition metal dichalcogenides (TMDCs). TMDCs share a common formula MeX2, where Me is a transition metal element from group four (Ti, Zr, Hf), five (V, Nb or Ta) or six (Mo, W), and X is a chalcogen (S, Se or Te). Their crystalline structure comprises an inner Me layer sandwiched by two X layers. Herein, thermal oxidation of the microscopic MoS2 flakes is reviewed. An impact of relative humidity is also mentioned.
  • 547
  • 26 Oct 2021
Topic Review
Low-Frequency Plasma-Enhanced Chemical Vapor Deposition (LFPECVD)
The low-frequency plasma-enhanced chemical vapor deposition in cyclohexane atmospheres is an easy-to-implement technology for carbon-based coatings deposition. LFPECVD (like RF PECVD), which has the capacity to be implemented in any scale, is widely used in industry.
  • 1.2K
  • 21 Oct 2021
Topic Review
Optimizing Sustainability Opportunities for Biochar
Biochar is most commonly considered for its use as a soil amendment, where it has gained attention for its potential to improve agricultural production and soil health. Twenty years of near exponential growth in investigation has demonstrated that biochar does not consistently deliver these benefits, due to variables in biochar, soil, climate, and cropping systems. While biochar can provide agronomic improvements in marginal soils, it is less likely to do so in temperate climates and fertile soils. Here, biochar and its coproducts may be better utilized for contaminant remediation or the substitution of nonrenewable or mining-intensive materials. 
  • 740
  • 18 Oct 2021
Topic Review
Nature of the Bounce in LQC and PQM
We present a review concerning quantum cosmology in the presence of cut-off physics. We analyze how the Wheeler–DeWitt equation describes the quantum Universe dynamics when a pure metric approach is concerned, showing that the primordial singularity is not removed by the quantum effects. We then analyze the main implications of applying Loop Quantum Gravity prescriptions to the minisuperspace model, i.e., we discuss the basic features of Loop Quantum Cosmology. For the isotropic Universe dynamics, we compare the original m0 scheme and the most commonly accepted formulation, i.e. the so-called ¯m scheme. Furthermore, some fundamental results concerning the Bianchi Universes are discussed. Finally, we consider some relevant criticisms about the real link between the full theory of LQG and its minisuperspace implementation, especially with respect to the preservation of the internal SU(2) symmetry. In the second part of the review, we consider the dynamics of the isotropic Universe and of the Bianchi models in the framework of Polymer Quantum Mechanics. We first address the polymerization in termsof the Ashtekar–Barbero–Immirzi connection and show how the resulting dynamics is isomorphic to the m0 scheme of LQC with a critical energy density of the Universe that depends on the initial conditions for the dynamics. Then we analyze the polymerization of volume-like variables, both for the isotropic and Bianchi I models, and we see that if the Universe volume (the cubed scale factor) is one of the configurational variables, then the resulting dynamics is isomorphic to that for the ¯m scheme of LQC, with the critical energy density value being fixed only by fundamental constants and the Immirzi parameter. Finally, we consider the polymer quantum dynamics of the homogeneous and inhomogeneous Mixmaster model by means of a metric approach. In particular, we compare the results obtained by using the volume variable, which leads to the emergence of a singularity-free and chaos-free cosmology, to the use of the standard Misner variable. In the latter case we deal with the surprising result of a cosmology that is still singular, and its chaotic properties depend on the ratio between the lattice steps for the isotropic and anisotropic variables. We conclude the review with some considerations of the problem of changing variables in polymer cosmology. In particular, on a semiclassical level, we consider how the dynamics can be properly mapped in two different sets of variables (at the price of having to deal with a coordinate dependent lattice step), and we infer some possible implications on the equivalence of the m0 and ¯m scheme of LQC.
  • 596
  • 09 Oct 2021
Topic Review
Ion Channel and Bioinformatics
Ion channels are linked to important cellular processes. The use of artificial intelligence (AI) in bioinformatics and computational molecular biology research has been growing fast over the last two decades. Bioinformatics methods attempt to model known biological structures and predict unknown ones. Versatile bioinformatics techniques are capable of storing the information processed in various biological and biophysical studies in the created databank, and calling and utilizing the information from the databank in pinpointing crucial molecular processes of an individual system or collective ones. The techniques thus help establish scientific links between various mechanisms and processes and produce concluding evidence that is otherwise often unattainable using conventional theoretical and experimental techniques. Besides, computational techniques are popularly found to model the biomolecular complexes in silico studies to mainly address their statics, dynamics, and energetics in an artificially constructed, yet mimicking the biological systems’ environment.
  • 606
  • 08 Oct 2021
Topic Review
Undernutrition in fragility hip fracture
Geriatric patients with hip fractures often experience overlap in problems related to nutrition, including undernutrition, sarcopenia, and frailty. Such problems are powerful predictors of adverse responses, although few healthcare professionals are aware of them and therefore do not implement effective interventions.
  • 837
  • 30 Sep 2021
Topic Review
Korean Taekwondo Athletes
This study aimed to present a standard and normal distribution of Taekwondo athletes’ physical characteristics and physical fitness profiles using a systematic review. A systematic search was conducted using four Korean databases (Research Information Sharing Service, National Digital Science Library, DBpia, and Korean Studies Information Service System). From 2010 to 2020, we reviewed 838 papers on Taekwondo athletes’ physical characteristics and physical fitness factors (e.g., body composition, muscle strength, muscular endurance, flexibility, cardiorespiratory fitness, power, agility, balance, speed, and reaction time).
  • 1.3K
  • 29 Sep 2021
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