Dynamic Response Study of Piezoresistive Ti3C2-MXene Sensor for Structural Impacts.

MXenes are a new family of two-dimensional (2D) nanomaterials. They are inorganic compounds of metal carbides/nitrides/carbonitrides. Titanium carbide MXene (Ti3C2-MXene) was the first 2D nanomaterial reported in the MXene family in 2011. Owing to the good physical properties of Ti3C2-MXenes (e.g., conductivity, hydrophilicity, film-forming ability, elasticity) various applications in wearable sensors, energy harvesters, supercapacitors, electronic devices, etc., have been demonstrated. This paper presents the development of a piezoresistive Ti3C2-MXene sensor followed by experimental investigations of its dynamic response behavior when subjected to structural impacts. For the experimental investigations, an inclined ball impact test setup is constructed. Stainless steel balls of different masses and radii are used to apply repeatable impacts on a vertical cantilever plate. The Ti3C2-MXene sensor is attached to this cantilever plate along with a commercial piezoceramic sensor, and their responses for the structural impacts are compared. It is observed from the experiments that the average response times of the Ti3C2-MXene sensor and piezoceramic sensor are 1.28±0.24µs and 31.19±24.61µs, respectively. The fast response time of the Ti3C2-MXene sensor makes it a promising candidate for monitoring structural impacts.

Emulating Clinical Diagnostic Reasoning for Jaw Cysts with Machine Learning.

The detection and classification of cystic lesions of the jaw is of high clinical relevance and represents a topic of interest in medical artificial intelligence research. The human clinical diagnostic reasoning process uses contextual information, including the spatial relation of the detected lesion to other anatomical structures, to establish a preliminary classification. Here, we aimed to emulate clinical diagnostic reasoning step by step by using a combined object detection and image segmentation approach on panoramic radiographs (OPGs). We used a multicenter training dataset of 855 OPGs (all positives) and an evaluation set of 384 OPGs (240 negatives). We further compared our models to an international human control group of ten dental professionals from seven countries. The object detection model achieved an average precision of 0.42 (intersection over union (IoU): 0.50, maximal detections: 100) and an average recall of 0.394 (IoU: 0.50-0.95, maximal detections: 100). The classification model achieved a sensitivity of 0.84 for odontogenic cysts and 0.56 for non-odontogenic cysts as well as a specificity of 0.59 for odontogenic cysts and 0.84 for non-odontogenic cysts (IoU: 0.30). The human control group achieved a sensitivity of 0.70 for odontogenic cysts, 0.44 for non-odontogenic cysts, and 0.56 for OPGs without cysts as well as a specificity of 0.62 for odontogenic cysts, 0.95 for non-odontogenic cysts, and 0.76 for OPGs without cysts. Taken together, our results show that a combined object detection and image segmentation approach is feasible in emulating the human clinical diagnostic reasoning process in classifying cystic lesions of the jaw.

A mega-cryptic species complex hidden among one of the most common annelids in the North East Atlantic.

We investigate mitochondrial (COI, 16S rDNA) and nuclear (ITS2, 28S rDNA) genetic structure of North East Atlantic lineages of Terebellides, a genus of sedentary annelids mainly inhabiting continental shelf and slope sediments. We demonstrate the presence of more than 25 species of which only seven are formally described. Species boundaries are determined with molecular data using a broad range of analytical methods. Many of the new species are common and wide spread, and the majority of the species are found in sympatry with several other species in the complex. Being one of the most regularly encountered annelid taxa in the North East Atlantic, it is more likely to find an undescribed species of Terebellides than a described one.

Synthesis of a Nonracemic C2-Symmetric Tetrahydro-1,4-azaborine and Evaluation of Hydroboration Enantioselectivity.

Tetrahydro-1,4-azaborines were accessed by hydroboration of N,N-diprenyltoluenesulfonamide 4. Conversion to the methylborinates 11 and 12 followed by heating with l-alanine and crystallization afforded (R,R,S)-13 (27%). Reduction of borinic acid (R,R)-18 with Soderquist's KH* gave (R,R)-19, and hydride abstraction by TMSCl in the presence of alkenes resulted in hydroboration, 84-86% ee for (Z)-alkenes, but (E)-alkenes or 1,1-disubstituted alkenes gave <5% ee.

Hormesis enables cells to handle accumulating toxic metabolites during increased energy flux.

Energy production is inevitably linked to the generation of toxic metabolites, such as reactive oxygen and carbonyl species, known as major contributors to ageing and degenerative diseases. It remains unclear how cells can adapt to elevated energy flux accompanied by accumulating harmful by-products without taking any damage. Therefore, effects of a sudden rise in glucose concentrations were studied in yeast cells. This revealed a feedback mechanism initiated by the reactive dicarbonyl methylglyoxal, which is formed non-enzymatically during glycolysis. Low levels of methylglyoxal activate a multi-layered defence response against toxic metabolites composed of prevention, detoxification and damage remission. The latter is mediated by the protein quality control system and requires inducible Hsp70 and Btn2, the aggregase that sequesters misfolded proteins. This glycohormetic mechanism enables cells to pre-adapt to rising energy flux and directly links metabolic to proteotoxic stress. Further data suggest the existence of a similar response in endothelial cells.

The Beneficial Effects of Cardiac Rehabilitation on the Function and Levels of Endothelial Progenitor Cells.

Cardiac rehabilitation (CR) is a comprehensive program, which mainly focusses on exercise training, disease evaluation, cardiovascular risk factors control, medication therapy, psychosocial intervention, and patient education. Although the beneficial properties of CR have been widely evidenced, its mechanism is still not completely clarified. To date, endothelial progenitor cells (EPCs) have been explored by emerging studies, and evidence has suggested that CR, especially exercise training, significantly increases the function and levels of EPCs, which is likely to elucidate the profiting mechanism of CR. Thus, this review summarises the potential relationship between CR and EPCs with an aim of providing novel directions for future CR research.

Synthesis and properties of lysosome-specific photoactivatable probes for live-cell imaging.

Fluorescent dyes have become increasingly important in cell biology since they enable high signal-to-noise and selectivity in visualizing subcellular organelles. Photoactivatable dyes allow for tracking and monitoring of a subset of cells or organelles. Here, we report the synthesis and application of a new class of large Stokes shift fluorescent dyes that are water-soluble, cell permeable, non-cytotoxic, and lysosome-specific. Additionally, we demonstrate temporally controlled sequential photoactivation of individual cells in close spatial proximity.

Synthesis and conformational dynamics of the reported structure of xylopyridine A.

Natural products have served as a rich source for the discovery of new nucleic acid targeting molecules for more than half a century. However, our ability to design molecules that bind nucleic acid motifs in a sequence- and/or structure-selective manner is still in its infancy. Xylopyridine A, a naturally occurring molecule of unprecedented architecture, has been found to bind DNA by a unique mode of intercalation. Here we show that the structure proposed for xylopyridine A is not consistent with the characterization in the original isolation report and does not bind B-form DNA. Instead, we report that the originally proposed structure for xylopyridine A represents a new class of conformationally dynamic structure-selective quadruplex nucleic acid binder. The unique molecular conformation locks out nonspecific intercalative binding modes and provides a starting point for the design of a new class of structure-specific nucleic acid binder.

Oxygen-directed intramolecular hydroboration.

Metal-free homoallylic oxygen-directed intramolecular hydroboration is reported. Regioselectivities from 20:1 to 82:1 favoring the 1,3-dioxy-substituted products have been achieved using Me2S.BH3/TfOH followed by standard oxidative workup. Branching at the C5 position improves regioselectivity.

Synthesis of (+)-bullatacin via the highly diastereoselective [3+2] annulation reaction of a racemic aldehyde and a nonracemic allylsilane.

[reaction: see text] A total synthesis of (+)-bullatacin has been accomplished via a diastereoselective [3+2] annulation reaction of the highly enantiomerically enriched allylsilane 3 and racemic aldehyde 4, which provides the key bis-tetrahydrofuran fragment 15 with > or = 20:1 ds.

Lipids and theirs carriers in sportsmen: the lipoprotein particles.

This study presents an original approach to the effect of regular sporting activity on the metabolism of lipids. We have examined the physiological variations of lipoparticles (Lp) AI, Lp B:CIII, Lp B:E, Lp (a) and the principal lipid markers in 21 high-level rugby players and men of the same age group who take part in no sporting activity (reference group; n = 35). The analysis showed a paradoxical decrease in the high-density lipoprotein fraction of cholesterol (P < 0.05) and in apolipoprotein AI (P < 0.0001), and an increase in the apoprotein B/apoprotein AI ratio in the sportsmen, compared with the reference group. According to these results, physical activity seems to have only a slight influence on anti-atherogenic serum markers. However, the drop in Lp B:E (P < 0.0001) and the static level of Lp AI in the sportsmen indicate a favourable effect of sport on these lipoparticles. The results of this study also highlight the importance of triglycerides and their metabolism. In fact, the lower triglyceride levels (P < 0.05) of the sportsmen justify special attention to diet, especially during a period of competition.