Biomechanical analysis and model development applied to table tennis forehand strokes

Table tennis playing involves complex spatial movement of the racket and human body. It takes much effort for the novice players to better mimic expert players. The evaluation of motion patterns during table tennis training, which is usually achieved by coaches, is important for novice trainees to improve faster. However, traditional coaching relies heavily on coaches qualitative observation and subjective evaluation. While past literature shows considerable potential in applying biomechanical analysis and classification for motion pattern assessment to improve novice table tennis players, little published work was found on table tennis biomechanics. To attempt to overcome the problems and fill the gaps, this research aims to quantify the movement of table tennis strokes, to identify the motion pattern differences between experts and novices, and to develop a model for automatic evaluation of the motion quality for an individual. Firstly, a novel method for comprehensive quantification and measurement of the kinematic motion of racket and human body is proposed. In addition, a novel method based on racket centre velocity profile is proposed to segment and normalize the motion data. Secondly, a controlled experiment was conducted to collect motion data of expert and novice players during forehand strokes. Statistical analysis was performed to determine the motion differences between the expert and the novice groups. The experts exhibited significantly different motion patterns with faster racket centre velocity and smaller racket plane angle, different standing posture and joint angular velocity, etc. Lastly, a support vector machine (SVM) classification technique was employed to build a model for motion pattern evaluation. The model development was based on experimental data with different feature selection methods and SVM kernels to achieve the best performance (F1 score) through cross-validated and Nelder-Mead method. Results showed that the SVM classification model exhibited good performance with an average model performance above 90% in distinguishing the stroke motion between expert and novice players. This research helps to better understand the biomechanical mechanisms of table tennis strokes, which will ultimately aid the improvement of novice players. The phase segmentation and normalization methods for table tennis strokes are novel, unambiguous and straightforward to apply. The quantitative comparison identified the comprehensive differences in motion between experts and novice players for racket and human body in continuous phase time, which is a novel contribution. The proposed classification model shows potential in the application of SVM to table tennis biomechanics and can be exploited for automatic coaching

Micellization and Thermodynamic Study of 1‑Alkyl-3-methylimidazolium Tetrafluoroborate Ionic Liquids in Aqueous Solution

Three surfactant-like ionic liquids, 1-dodecyl-3-methylimidazolium tetrafluoroborate (C₁₂mimBF₄), 1-tetradecyl-3-methylimidazolium tetrafluoroborate (C₁₄mimBF₄), and 1-hexadecyl-3-methylimidazolium tetrafluoroborate (C₁₆mimBF₄) had been systematically studied by conductivity measurement, surface tension, steady-state fluorescence measurement and ultraviolet (UV) absorption spectra at 298.15 K. Micellization of the three ILs were certified by the above methods and aggregation number of micelles (<i>N</i>_agg) were determined by pyrene fluorescence quenching method. A comparison of C_<i>n</i>mimBF₄ with different alkyl chain lengths shows that that the critical micelle concentration (cmc) decreased remarkably with the increase of alkyl chain length, but the surface tensions at cmc (γ_cmc) were approximately the same, except for that of C₁₆mimBF₄. The effects of temperature, inorganic salt, and organic alcohols on the cmc of C_<i>n</i>mimBF₄ (<i>n</i> = 12, 14, 16) aqueous solution were also investigated. The results showed that the cmc values assumed a trend of increase along with the increase of temperature, and decreased remarkably with the presence of inorganic salt. For alcohol–water systems at lower temperature, the cmc values increased with the presence of short chain alcohols (ethanol, 1-propanol), but decreased or were invariable with long chain alcohols (1-butanol, 1-pentanol). Finally, the micellization thermodynamic parameters (Δ<i>G</i>_m°, Δ<i>H</i>_m°, Δ<i>S</i>_m°) of C_<i>n</i>mimBF₄ (<i>n</i> = 12, 14, 16) showed that the micelle formation process of C₁₂mimBF₄ was entropy-driven, and the micellization behavior of C₁₄mimBF₄ and C₁₆mimBF₄ was found to be an enthalpy-driven process in the investigated temperature range

Synthesis and Desulfurization Performance of Functional Silica Gel Modified by Polymeric 1‑Vinyl-3-ethylimidazolium Tetrafluoroborate Ionic Liquids

Polymeric 1-vinyl-3-ethylimidazolium tetrafluoroborate ionic liquids modified microspheres of silica gel were prepared by free radical polymerization in toluene. Characterization with Fourier transform infrared (FTIR), elemental analysis, scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), gel permeation chromatography (GPC), thermogravimetric analysis (TGA), and ¹³C, ²⁹Si magic angle spinning (MAS) nuclear magnetic resonance (NMR) demonstrated that 1-vinyl-3-ethylimidazolium tetrafluoroborate had successfully loaded on the surface of silica gel and formed a stable polymer coating. Furthermore, to detect the potential desulfurization performance, a series of experiments of model fuel desulfurization with polymeric ionic liquid modified silica gel had been carried out. The desulfurization efficiency of modified silica gel was investigated by removing 2-methylthiophene, benzothiophene, and dibenzothiophene from model fuel (<i>n</i>-heptane/2-methylthiophene, benzothiophene, and dibenzothiophene) under tested conditions. It was shown that the modified silica gel exhibited remarkable desulfurization capacity for aromatic S-containing compounds and the sulfur removal selectivity followed the order of 2-methylthiophene < benzothiophene < dibenzothiophene due to the different density aromatic π-electrons

Salt-Induced Assembly Transformation of DNA–AuNP Conjugates Based on RCA Origami: From Linear Arrays to Nanorings

We developed a simple method to adjust the structural transformation of DNA–gold nanoparticles assemblies from linear arrays to nanorings by increasing salt concentrations. A DNA nanoladder constructing from RCA origami acted as templates to assemble periodic AuNPs arrays by a terminal thiol located on staple oligonucleotides. The linear AuNPs arrays could be transformed into nanorings only by changing the concentration of NaCl aqueous solution during the assembly process. It was proven that the electrostatic repulsion, being asymmetrically diminished by the high concentration of NaCl, caused the formation of nanoring architectures

Rolling Circle Amplification-Based DNA Nano-Assembly for Targeted Drug Delivery and Gene Therapy

Combining the killing ability of chemotherapy drugs on tumor cells with the inhibiting ability of genetic drugs on tumor cell growth, a dual drug delivery system loaded with therapy drugs and siRNA has gradually received more and more research and extensive attention. In this paper, we designed a DNA nano-assembly based on rolling circle amplification that can co-deliver doxorubicin (Dox) and siRNA simultaneously. In order to fully exploit the potential of the dual loading system in cancer treatment, we selected STAT3 gene as a target and used siRNA to target STAT3 of mRNA and reduce the STAT3 expression in mouse melanoma cell line (B16); meanwhile, Dox as a chemotherapy drug was combined with multivalent aptamers specifically targeting B16 to achieve efficient delivery of siRNA and Dox. The results showed that the synergistic delivery system could achieve high efficiency in targeting and inhibiting proliferation in mouse melanoma cells. In addition, the synergistic effect of the dual delivery system on apoptosis of cancer cells was significantly better than that of single drug delivery systems

The value of bioimpedance analysis in the assessment of hydration and nutritional status in children on chronic peritoneal dialysis

Bioimpedance analysis (BIA)–body composition monitoring (BCM) has been used to evaluate the hydration and nutritional status of adults and children on dialysis. However, its clinical application still has challenges, so further exploration is valuable. We used BIA-BCM to evaluate the hydration and nutritional status of children undergoing chronic peritoneal dialysis from 1 July 2021 to 31 December 2022 in the Children’s Hospital of Fudan University to explore the clinical value of this method. A total of 84 children on chronic peritoneal dialysis (PD) were included. In the PD group, 16 (19.05%) and 31 (36.90%) had mild and severe overhydration (OH), respectively; 41.27% (26/63) had a low lean tissue index (LTI). In the PD group, patients with relative OH (Re-OH) > 5.6% had significantly higher systolic blood pressure (SBP) and SBP z score (SBPz). Patients with LTI > 12% had significantly higher body mass index (BMI) and BMI z score (BMIz). Canonical correlation analysis indicated a linear relationship (ρ = 0.708) between BIA-BCM hydration and the clinical hydration indicator and a linear relationship (ρ = 0.995) between the BIA-BCM nutritional indicator and the clinical nutritional indicator. A total of 56% of children on chronic peritoneal dialysis had OH, and 41% had a low LTI. In PD patients, SBP and SBPz were correlated with BIA-BCM Re-OH, and BMI and BMIz were correlated with BIA-BCM LTI. BIA-BCM indicators have good clinical value in evaluating hydration and nutrition.</p

The Combination of RAD001 and MK-2206 Exerts Synergistic Cytotoxic Effects against PTEN Mutant Gastric Cancer Cells: Involvement of MAPK-Dependent Autophagic, but Not Apoptotic Cell Death Pathway

<div><p>In the current study, we showed that the combination of mammalian target of rapamycin (mTOR) inhibitor RAD001 (everolimus) and Akt inhibitor MK-2206 exerted synergistic cytotoxic effects against low-phosphatase and tensin homolog (PTEN) gastric cancer cells (HGC-27 and SNU-601 lines). In HGC-27 cells, RAD001 and MK-2206 synergistically induced G1/S cell cycle arrest, growth inhibition, cell death but not apoptosis. RAD001 and MK-2206 synergistically induced light chain 3B (LC3B) and beclin-1 expression, two important autophagy indicators. Meanwhile, the autophagy inhibitor 3-methyladenine (3-MA) and chloroquine inhibited the cytotoxic effects by RAD001 and MK-2206, suggesting that autophagic, but not apoptotic cell death was important for the cytotoxic effects by the co-administration. We observed that the combination of RAD001 and MK-2206 exerted enhanced effects on Akt/mTOR inhibition, cyclin D1 down-regulation and ERK/MAPK(extracellular signal-regulated kinase/mitogen-activated protein kinases) activation. Intriguingly, MEK/ERK inhibitors PD98059 and U0126 suppressed RAD001 plus MK-2206-induced beclin-1 expression, autophagy induction and cytotoxicity in HGC-27 cells. In conclusion, these results suggested that the synergistic anti-gastric cancer cells ability by RAD001 and MK-2206 involves ERK-dependent autophagic cell death pathway.</p></div

RAD001 and MK-2206 together induces HGC-27 cell G1/S arrest.

<p>HGC-27 cells were treated for 48 h with RAD001 (10 nM) and/or MK-2206 (100 nM), cell cycle was analyzed by FACS as described (A–D). (E) summarized the HGC-27 cell cycle distributions after RAD001 (10 nM) and/or MK-2206 (100 nM) treatment. The results in this figure were from repeated three independent experiments, with similar results obtained. *<i>p</i><0.05.</p

The combination of RAD001 and MK-2206 exerts enhanced effects on Akt/mTOR suppression and cyclin D1 down-regulation.

<p>HGC-27 cells were treated for 24 h with RAD001 (10 nM) and/or MK-2206 (100 nM), phospho- and total levels of Akt, mTOR, S6 and 4E-BP1 (A and B) as well as expression levels of cyclin D1 and β-actin (C) were detected by western blots. The relative expression level of p-mTOR, p-S6, p-4E-BP1, p-Akt (Ser 473, Thr 308) and cyclin D1 was quantified as described; the number was expressed as fold change vs. the corresponding band of DMSO. Experiments in this figure were repeated three times and similar results were obtained. *<i>p</i><0.05.</p

RAD001 and MK-2206 synergistically inhibits the growth of HGC-27 and SNU-601 cells.

<p>HGC-27, SNU-601, SGC-7901, MKN-28 and GES-1 cells were treated for 72 h with different concentration of RAD001 and/or MK-2206 with different ratio. Inhibition of cell growth was measured by CCK-8 cell viability assay (A–E). The data shown are the mean from three independent experiments, each with six wells.</p