Highly Sensitive Impact Sensor Based on PVDF-TrFE/Nano-ZnO Composite Thin Film.

A thin film of polyvinylidene fluoride-trifluoroethylene (PVDF-TrFE) has good flexibility and simple preparation process. More importantly, compared with PVDF, its piezoelectric ß-phase can be easily formed without mechanical stretching. However, its piezoelectricity is relatively lower. Therefore, at present, PVDF-TrFE is always compounded with other kinds of piezoelectric materials to solve this problem. The effect of nano-ZnO doping amount on the sensing characteristics of the piezoelectric films was studied. PVDF-TrFE/nano-ZnO films with different nano-ZnO contents were prepared by spin coating process and packaged. The dispersion of nano-ZnO dopants and the crystallinity of ß-phase in piezoelectric films with different nano-ZnO contents were observed by scanning electron microscopy and X-ray diffraction, and the piezoelectric strain constants and dielectric constants were measured, respectively. The effect of different nano-ZnO contents on the output performance of the piezoelectric sensor was obtained by a series of impact experiments. The results show that the piezoelectric strain constant and dielectric constant can be increased by doping nano-ZnO in PVDF-TrFE. Moreover, the doping amount of nano-ZnO in PVDF-TrFE is of great significance for improving the piezoelectric properties of PVDF-TrFE/nano-ZnO thin films. Among the prepared piezoelectric films, the output voltage of PVDF-TrFE/nano-ZnO piezoelectric sensor with 7.5% nano-ZnO doping amount is about 5.5 times that of pure PVDF-TrFE. Thus, the optimal range of the doping amount for nano-ZnO is about 4⁻10%.

Rescue analgesia with serratus anterior plane block improved pain relief after thoracic surgery.

BACKGROUND: Video-assisted thoracic surgery (VATS) is frequently associated with substantial postoperative pain, which may lead to hypopnea. Rescue analgesia using opioids has adverse effects. We aimed to evaluate the effects of rescue analgesia with serratus anterior plane block (SAPB) on moderate-to-severe pain and oxygenation in patients undergoing VATS. METHODS: Eighty patients undergoing VATS and reporting a numeric rating scale (NRS, ranging from 0-10) score of cough pain ≥4 on the first postoperative day were randomized to receive either sufentanil or SAPB for rescue analgesia. The primary outcome was the degree of relief in cough pain 30 min after rescue analgesia. Arterial oxygen pressure (PaO2), opioid consumption after rescue analgesia and the incidence of chronic pain were also assessed. RESULTS: The NRS scores were significantly reduced after rescue analgesia in both groups (Ppaired <0.001). Notably, the degree of relief in cough pain was significantly higher in the SAPB group than that in the sufentanil group (medians [interquartiles]: -3 [-4, -2] vs. -2 [-3, -1], P<0.001). Moreover, patients receiving SAPB exhibited significantly higher PaO2 than those before receiving rescue analgesia (Ppaired=0.007). However, there were no significant differences in the PaO2 before and after receiving rescue analgesia in the sufentanil group. No significant differences in opioid consumption or the incidence of chronic pain were observed between groups. CONCLUSIONS: Rescue analgesia with SAPB on the first postoperative day had a greater effect on pain relief and oxygenation after VATS. However, its long-term effect on chronic pain requires further research.

Effect of S-ketamine administered at the end of anesthesia on emergence delirium in preschool children undergoing tonsillectomy and/or adenoidectomy.

Background: S-ketamine (the S-isomer of ketamine) is twice as potent as the racemic mixture of this agent and carries fewer side effects when administered to humans. Information regarding the use of S-ketamine for the prevention of emergence delirium (ED) is limited. Thus, we evaluated the effect of S-ketamine administered at the end of anesthesia on ED in preschool children undergoing tonsillectomy and/or adenoidectomy. Methods: We investigated 108 children aged 3-7 years, who were scheduled for elective tonsillectomy and/or adenoidectomy under general anesthesia. They were randomly assigned to receive either S-ketamine 0.2 mg/kg or an equal volume of normal saline at the end of anesthesia. The primary outcome was the highest score on the pediatric anesthesia ED (PAED) scale during the first 30 min post-surgery. The secondary outcomes included the incidence of ED (defined as a score of ≥ 3 on Aono scale), pain score, time to extubation, and incidences of adverse events. Multivariate analyses were also performed using logistic regression to evaluate the independent factors predictive of ED. Results: The median (interquartile range) PAED score of the S-ketamine group (0 [0, 3]) was significantly lower than that in the control group (1 [0, 7]) (estimate median difference = 0, 95% confidence interval -2 to 0, p = 0.040). Significantly fewer patients in the S-ketamine group had an Aono scale score ≥ 3 (4 [7%] vs. 12 [22%], p = 0.030). Patients in the S-ketamine group also had a lower median pain score than did control subjects (4 [4, 6] vs. 6 [5, 8], p = 0.002). The time to extubation and incidences of adverse events were comparable between the two groups. However, multivariate analyses indicated that except S-ketamine use, pain scores, age and duration of anesthesia were independent factors predictive of ED. Conclusion: S-ketamine (0.2 mg/kg) administered at the end of anesthesia effectively reduced the incidence and severity of ED in preschool children undergoing tonsillectomy and/or adenoidectomy without prolonging the time to extubation or increasing adverse events. However, S-ketamine use was not an independent factor predictive of ED.

Comparative study on the interaction between flavonoids with different core structures and hyaluronidase.

Hyaluronidase (HAase) is an important enzyme involved in a promoting inflammation pathway. Flavonoids are a group of major polyphenols including flavonols (such as myricetin and rutin), dihydroflavones (such as naringin and hesperidin), and isoflavones (such as genistein and puerarin), which have been proved to possess anti-inflammatory effects. In this study, the binding of the six flavonoids to HAase was investigated by steady state and time-resolved fluorescence, circular dichroism (CD) spectroscopy and molecular docking methods. Fluorescence data reveal that the fluorescence quenching mechanism of HAase by flavonoids is all static quenching procedure regardless of their core structure. The binding affinity is strongest for rutin and ranks in the order rutin > hesperidin > myricetin > puerarin > genistein > naringin. The thermodynamic analysis implies that hydrophobic interaction, electrostatic force and hydrogen bonding are the main interaction forces. Synchronous fluorescence spectroscopy and CD spectroscopy indicate that flavonoids have the same core structure and have similar effects on the microenvironment around Trp and Tyr residues and the secondary structure of HAase. The results of molecular docking show that the binding of flavonoids with the catalytic amino acid residues of HAase may lead to the decrease of enzyme activity.

Exploring the interactions of naringenin and naringin with trypsin and pepsin: Experimental and computational modeling approaches.

Naringenin and naringin are two natural compounds with important health benefits, whether as food or drug. It is necessary to study the interactions between naringenin/naringin and digestive proteases, such as trypsin and pepsin. In this study, the bindings of naringenin and naringin to trypsin and pepsin were investigated using multi-spectroscopy analysis and computational modeling approaches. Fluorescence experiments indicate that both naringenin and naringin can quench the intrinsic fluorescence of trypsin/pepsin via static quenching mechanism. Naringin binds trypsin/pepsin in a more firmly way than naringenin. Thermodynamic analysis reveals that the interactions of naringenin/naringin and trypsin/pepsin are synergistically driven by enthalpy and entropy, and the major driving forces are hydrophobic, electrostatic interactions and hydrogen bonding. Synchronous fluorescence spectroscopy, circular dichroism spectroscopy and FT-IR show that naringenin/naringin may induce microenvironmental and conformational changes of trypsin and pepsin. Molecular docking reveals that naringenin binds in the close vicinity of the active site (Ser-195) of trypsin and Asp-32 (the catalytic activity of pepsin) appears in naringin-pepsin system. The direct interactions between naringenin or naringin and catalytic amino acid residues will inhibit the catalytic activity of trypsin and pepsin, respectively. The results of molecular dynamic simulation validate the reliability of the docking results.