External invasive resorption: Possible coexisting factors and demographic and clinical characteristics

The purpose of this retrospective study was to identify the coexisting factors for EIR and to characterise EIR clinically and demographically. All cases of EIR that were referred to the endodontic department between 2011 to 2016 and diagnosed by an endodontist were evaluated. Demographic and clinical characteristics were collected and evaluated. Thirty‐eight cases of EIR diagnosed between 2011 and 2016 were included in the study. Seventy‐one percent of EIR cases were misdiagnosed by general practitioners. The most affected teeth were the maxillary central incisors (29% of cases) and mandibular molars (26%). Sixty‐eight percent of EIR cases were diagnosed in teeth with clinically normal pulp. Pulp necrosis was observed mainly in the advanced stages (class 3 and class 4) of EIR (75%) and in teeth with a history of trauma (63%). Histories of previous trauma and orthodontic treatment were reported in 29% and 23% of cases, respectively.     

Reactive Powder Concrete Microstructure and Particle Packing

The subject of this study is the dispersed composition of multicomponent cement systems. This study aims to reduce interparticle voids, increasing the strength and concentration of the solid phase. The investigated concrete mixture contained two fine aggregate fractions, granite-gabbro crushed stone of 5–10 mm fraction, Portland cement of CEM I 42.5N class, finely dispersed granular blast furnace slag, microsilica, highly dispersed cement fraction, superplasticizer Glenium 430, and high-valence hardening accelerator. A laser analyzer determined the shape and size of dispersed particles of the components. The structure of the cement stone was studied by scanning microscopy, thermographic, and X-ray phase analysis methods. The strength of concrete with an optimized dispersed composition at the age of 2 days was 52, 63, and 74 MPa, while that at the age of 28 days was 128, 137, and 163 MPa. For this concrete, the consumption of multicomponent cement was 650, 700, and 750 kg/m³, respectively. The high efficiency of the application of bimodal clinker component and granulated blast-furnace slag is shown. It is established that the optimal content of nanoscale additives, including microsilica, should be insignificant and determined experimentally.     

Label-free sensing of cells with fluorescence lifetime imaging: The quest for metabolic heterogeneity

Molecular, morphological, and physiological heterogeneity is the inherent property of cells which governs differences in their response to external influence. Tumor cell metabolic heterogeneity is of a special interest due to its clinical relevance to tumor progression and therapeutic outcomes. Rapid, sensitive, and noninvasive assessment of metabolic heterogeneity of cells is a great demand for biomedical sciences. Fluorescence lifetime imaging (FLIM), which is an all-optical technique, is an emerging tool for sensing and quantifying cellular metabolism by measuring fluorescence decay parameters of endogenous fluorophores, such as NAD(P)H. To achieve accurate discrimination between metabolically diverse cellular subpopulations, appropriate approaches to FLIM data collection and analysis are needed. In this paper, the unique capability of FLIM to attain the overarching goal of discriminating metabolic heterogeneity is demonstrated. This has been achieved using an approach to data analysis based on the nonparametric analysis, which revealed a much better sensitivity to the presence of metabolically distinct subpopulations compared to more traditional approaches of FLIM measurements and analysis. The approach was further validated for imaging cultured cancer cells treated with chemotherapy. These results pave the way for accurate detection and quantification of cellular metabolic heterogeneity using FLIM, which will be valuable for assessing therapeutic vulnerabilities and predicting clinical outcomes.

Solid tumors are complex systems characterized by spatial heterogeneity at the genetic, molecular, and cellular levels. Tumor heterogeneity is the critical phenomenon determining the difference in therapeutic outcomes for patients with similar histological diagnosis (1, 2). The development of omics technologies allowed for a detailed investigation of molecular pathways responsible for tumor heterogeneity, which is now considered to be a prerequisite for fast tumor growth rather than just a consequence of the neoplastic transformation and multiple mutations. Metabolic heterogeneity, i.e., the difference in cancer cell metabolism within a tumor and between tumors, is considered to be a negative prognostic factor and is accompanied by an increased probability of recurrence and higher mortality (3). The basis of metabolic heterogeneity is the ability of cancer cells to adapt to nonuniform microenvironment, e.g., local hypoxia and nutrient limitation (2), and some factors intrinsic to the cancer cells, e.g., differentiation state, proliferative activity, and genetic alterations (4).Cancer cells are capable of switching between different metabolic pathways (e.g., aerobic glycolysis and oxidative phosphorylation) depending on the local conditions. This phenomenon is known as metabolic plasticity (5). Therefore, the metabolic status may be highly variable for the cells within a single tumor and between different tumors of the same type (6–9). Evidently, visualization and quantification of metabolic heterogeneity could be helpful for optimization of cancer treatment. Hence, methods allowing for rapid, sensitive, and noninvasive assessment of cellular metabolic heterogeneity are a high demand for oncology.During the last decade, fluorescence lifetime imaging (FLIM) (10), which is an all-optical technique, has proven to be a useful tool to characterize cellular metabolic state on a label-free basis. Metabolic imaging by FLIM is based on measuring fluorescence decay parameters (FDPs) of endogenous fluorophores, such as reduced nicotinamide adenine dinucleotide (phosphate) NAD(P)H and oxidized flavin adenine dinucleotide, FAD, which are involved in a number of redox reactions within the cell. It is now established that FLIM is sensitive to alterations in energy metabolism accompanying carcinogenesis (11) and cancer cell response to therapies and that it correlates with standard biochemical and molecular assays (12–14). It was shown that FLIM enables visualization of cellular metabolic heterogeneity of cancer, both intrinsic and induced by anticancer therapy (15–22). However, a detailed performance comparison of different FLIM data analysis methods in quantification of metabolic heterogeneity (variability) in populations of cells has not been considered.The FLIM-based assessment of metabolic heterogeneity at the cellular level can be reduced to the problem of discrimination between several subpopulations of cells which differ in their FDPs. Therefore, it is important to find a way that provides the highest sensitivity to discriminate between metabolically different subpopulations of cells. First, the FLIM image can be analyzed as a whole, and, consequently, the overall distribution of FDPs is analyzed over all pixels of the image. Another option is the segmentation of the image into individual objects (single cells, organelles, etc.), calculation of FDPs for each object, and analysis of the FDP distribution for the segmented objects. Both approaches are used in the literature, but there is a general understanding that the latter is more sensitive to the presence of cell subpopulations different in their metabolism (21–23). Second, the FLIM data can be processed either parametrically, i.e., by fitting the decay curves to a model [e.g., biexponential decay in the case of NAD(P)H and FAD] or nonparametrically. The latter approach includes the analysis of phasor plots (24, 25) or using different clustering algorithms (26), Bayesian frameworks (27, 28), and deep neural networks (29). Nonparametric methods of FLIM data analysis are extensively used due to the simplicity of interpretation of the results and the lack of necessity for data fitting, which may require calculation time. The workflow for the assessment of cancer cell metabolic heterogeneity using clustering of FDPs is schematically presented in Fig. 1.Open in a separate windowFig. 1.Illustration of tumor metabolic heterogeneity evaluation using FLIM. (A) Cancer cells are examined using metabolic FLIM, which provides the kinetics of fluorescence decay from each pixel of the image. The obtained fluorescence decay signal depends on the metabolic state of the cell and can further be analyzed using various parametric and nonparametric methods, which can accurately predict metabolically distinct subpopulations. (B) Automatic segmentation of cells in FLIM images using artificial intelligence (AI)-based approaches allows for the assessment of metabolic heterogeneity on a single cell level.In this paper, we present the results of assessment of cancer cell metabolic heterogeneity on the basis of FLIM of NAD(P)H for the simulated and experimental data using parametric (fitting to biexponential decay model) and nonparametric (phasor plot and K-means clustering) methods. By calculating the dimensionless bimodality index (BI), which characterizes the presence of two clusters of cells, we aimed at a quantitative comparison between the sensitivity of different approaches to FLIM data analysis in search of metabolic heterogeneity. To support the numerical simulation results, the metabolic heterogeneity was assessed in a colorectal cancer cell line and in primary cell cultures derived from patients’ colorectal tumor upon chemotherapy. The obtained results pave the way for a more precise detection and quantification of cellular metabolic heterogeneity using FLIM.     

Sleep in the lesser mouse-deer (Tragulus kanchil)

The mouse-deer or chevrotains are the smallest of the ungulates and ruminants. They are characterized by a number of traits which are considered plesiomorphic for the Artiodactyla order. The objective of this study was to examine sleep in the lesser mouse-deer (Tragulus kanchil), which is the smallest in this group (body mass < 2.2 kg). Electroencephalogram, nuchal electromyogram, electrooculogram, and body acceleration were recorded in four adult mouse-deer females using a telemetry system in Bu Gia Map National Park in Vietnam. The mouse-deer spent on average 49.7 ± 3.0% of 24 h in non-rapid eye movement (NREM) sleep. REM sleep occupied 1.7 ± 0.3% of 24 h or 3.2 ± 0.5% of total sleep time. The average duration of REM sleep episodes was 2.0 ± 0.2 min, the average maximum was 5.1 ± 1.1 min, and the longest episodes lasted 8 min. NREM sleep occurred in sternal recumbency with the head held above the ground while 64.7 ± 6.4% of REM sleep occurred with the head resting on the ground. The eyes were open throughout most of the NREM sleep period. The mouse-deer displayed polyphasic sleep and crepuscular peaks in activity (04:00–06:00 and 18:00–19:00). The largest amounts of NREM occurred in the morning (06:00–09:00) and the smallest before dusk (at 04:00–06:00). REM sleep occurred throughout most of the daylight hours (08:00–16:00) and in the first half of the night (19:00–02:00). We suggest that the pattern and timing of sleep in the lesser mouse-deer is adapted to the survival of a small herbivorous animal, subject to predation, living in high environmental temperatures in the tropical forest undergrowth.     

Li-based layered nickel–tin oxide obtained through electrochemically-driven cation exchange

The Li-based layered nickel-tin oxide Li_0.35Na_0.07Ni_0.5Sn_0.5O₂ has been synthesized via electrochemically-driven Li⁺ for Na⁺ exchange in O3-NaNi_0.5Sn_0.5O₂. The crystal structure of Li_0.35Na_0.07Ni_0.5Sn_0.5O₂ was Rietveld-refined from powder X-ray diffraction data (a = 3.03431(7) Å, c = 14.7491(8) Å, S. G. R$\bar{3}$m). It preserves the O3 stacking sequence of the parent compound, but with ∼13% lower unit cell volume. Electron diffraction and atomic-resolution scanning transmission electron microscopy imaging revealed short-range Ni/Sn ordering in both the pristine and Li-exchanged materials that is similar to the “honeycomb” Li/M ordering in Li₂MO₃ oxides. As supported by bond-valence sum and density functional theory calculations, this ordering is driven by charge difference between Ni²⁺ and Sn⁴⁺ and the necessity to maintain balanced bonding for the oxygen anions. Li_0.35Na_0.07Ni_0.5Sn_0.5O₂ demonstrates reversible electrochemical (de)intercalation of ∼0.21 Li⁺ in the 2.8–4.3 V vs. Li/Li⁺ potential range. Limited electrochemical activity is attributed to a formation of the surface Li/Ni disordered rock-salt barrier layer as the Li⁺ for Na⁺ exchange drastically reduces the energy barrier for the Li/Ni antisite disorder.

Layered O3-Li_0.35Na_0.07Ni_0.5Sn_0.5O₂ cathode material was obtained by electrochemically-driven Li for Na exchange. The exchange process was comprehensively studied via a combination of transmission electron microscopy techniques.     

Electrochemical Improvement of the MWCNT/Al Electrodes for Supercapacitors

An original technique of chemical deposition (CVD) by catalytic pyrolysis of ethanol vapor was used to directly grow multiwall carbon nanotubes (MWCNTs) layers on aluminum foil. The grown nanotubes had excellent adhesion and direct electrical contact to the aluminum substrate. This material was perfect for use in electrochemical supercapacitors. In this work, the possibility of a significant increase in the specific capacity of MWCNTs by simple electrochemical oxidation was investigated. The optimal conditions for improving the characteristics of the MWCNT/Al electrodes were found. Electrochemical treatment of MWCNT/Al electrodes in a 0.005 M Na₂SO₄ solution at a potential of 4–5 V for 20–30 min increased the specific capacity of MWCNTs from 30 F/g to 140 F/g. The properties of modified nanotubes were investigated by X-ray photoelectron spectroscopy, cyclic voltammetry (CV), and impedance spectroscopy. A significant increase in the concentration of oxygen-containing functional groups on the surface of MWCNTs was found as a result of electrochemical oxidation. The modified MWCNT/Al electrodes maintained excellent stability to multiple charge–discharge cycles. After 20,000 CVs, the capacity loss was less than 5%. Thus, the results obtained significantly expanded the possibilities of using MWCNT/Al composite materials obtained by the method of direct deposition of carbon nanotubes on aluminum foil as electrodes for supercapacitors.     

Histological characterization of age‐related skin changes following the use of picosecond laser: Low vs high energy

Fractional lasers have become widespread in dermatology owing to their efficacy and safety. Comparative analysis of histological features after laser rejuvenation using a 1064‐nm fractionated handpiece picosecond laser with different energy fluence levels (1.1 or 2.1 J/cm²). An open‐label, study of 28 women aged 36 to 60 years with signs of age‐related photodamage and skin changes of the face and neck was conducted using a fractional picosecond 1064 nm laser in low vs high fluence. The clinical assessment at 3 weeks showed more pronounced effect on facial skin rejuvenation with the higher fluence of 2.1 J/cm² compared to 1.1 J/cm². The effect and safety of laser rejuvenation using a picosecond laser has been shown with more pronounced histological effects at higher fluences.