Ag-doped TiO2 coatings were successfully fabricated on Ti using plasma electrolytic oxidation (PEO) in the electrolytes containing Ag or Ag2O nanoparticles (NPs). The results showed that the ...different Ag sources resulted in significant variations of morphology, composition and chemical state. The thermal decomposition of Ag2O during PEO process contributed to the formation of Ag NPs, which might reactively incorporate into TiO2, leading to the presence of a Ca, P-rich amorphous layer between entrapped Ag NPs and the peripheral TiO2. By contrast, Ag specie tends to be present as micro-sized clusters consisting of metallic Ag NPs in the PEO coating fabricated via Ag NPs addition. The different microstructures inevitably affected the Ag ionic release behaviour and thus antibacterial capabilities and cytocompatibilities. It is indicated that the application of Ag2O NPs as Ag source is promising to fabricate Ag-doped PEO coating with both long-term antibacterial activity and acceptable cytocompatibility.
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•Different Ag sources lead to significant variations of microstructure and biological performance.•Ag2O nanoparticles could result in both inert and reactive incorporations of Ag into TiO2.•Silver ionic releases from Ag-doped TiO2 coatings significantly affect their antibacterial activities.
Background
White light (WL) and weak-magnifying (WM) endoscopy are both important methods for diagnosing gastric neoplasms. This study constructed a deep-learning system named ENDOANGEL-MM ...(multi-modal) aimed at real-time diagnosing gastric neoplasms using WL and WM data.
Methods
WL and WM images of a same lesion were combined into image-pairs. A total of 4201 images, 7436 image-pairs, and 162 videos were used for model construction and validation. Models 1–5 including two single-modal models (WL, WM) and three multi-modal models (data fusion on task-level, feature-level, and input-level) were constructed. The models were tested on three levels including images, videos, and prospective patients. The best model was selected for constructing ENDOANGEL-MM. We compared the performance between the models and endoscopists and conducted a diagnostic study to explore the ENDOANGEL-MM’s assistance ability.
Results
Model 4 (ENDOANGEL-MM) showed the best performance among five models. Model 2 performed better in single-modal models. The accuracy of ENDOANGEL-MM was higher than that of Model 2 in still images, real-time videos, and prospective patients. (86.54 vs 78.85%,
P
= 0.134; 90.00 vs 85.00%,
P
= 0.179; 93.55 vs 70.97%,
P
< 0.001). Model 2 and ENDOANGEL-MM outperformed endoscopists on WM data (85.00 vs 71.67%,
P
= 0.002) and multi-modal data (90.00 vs 76.17%,
P
= 0.002), significantly. With the assistance of ENDOANGEL-MM, the accuracy of non-experts improved significantly (85.75 vs 70.75%,
P
= 0.020), and performed no significant difference from experts (85.75 vs 89.00%,
P
= 0.159).
Conclusions
The multi-modal model constructed by feature-level fusion showed the best performance. ENDOANGEL-MM identified gastric neoplasms with good accuracy and has a potential role in real-clinic.
In the present work, Zn-incorporated TiO2 coatings are prepared through a one-step micro-arc oxidation (MAO) method on a grade 4 pure titanium with the addition of either Na2Zn-EDTA solution or ZnO ...nanoparticles (NPs) as Zn sources. The microstructural features of both Zn-incorporated TiO2 coatings were systematically examined. It is revealed that different Zn sources result in significant difference of phase component, chemical state, composition and morphology between the resultant Zn-incorporated MAO coatings. Zn species could be present as ZnO and Zn(OH)2 in the coating when Na2Zn-EDTA was used as Zn source whereas the presence of ZnO nano-clusters is obvious on the coating surface with ZnO NPs as Zn source. The addition of ZnO NPs during the MAO process also leads to a lower Zn content of the resultant coating, which is more defective with increased thickness in comparison to that of Na2Zn-EDTA. Further, antibacterial property and osteogenic activity of both Zn-incorporated coatings were examined. Both Zn-incorporated coatings exhibit favourable bacterial inhibition ability and bone formability, suggesting the successful synthesis of bifunctional coatings through the facile one-step micro-arc oxidation method.
Frequency stepping is a widely used technique for ultrahigh-resolution synthetic aperture radar (SAR). Although reducing the burden of hardware, this technique increases the complexity of imaging ...algorithms due to the intersubband time offsets and intersubband errors of delay, amplitude, and phase. To address the above problems, an improved ultrahigh-resolution stepped-frequency spaceborne SAR imaging algorithm is proposed in this article. By generating subband images individually, performing intersubband error estimation based on primary points, and then synthesizing the subband images in the imaging domain, the proposed algorithm effectively avoids the problem of time offsets and significantly improves intersubband error compensation accuracy benefiting from the high SNR in the imaging domain. Besides, considering the characteristics of nonideal factors in frequency-stepped SAR, a series of error compensation methods aiming at stop-and-go approximation, ionospheric error, and tropospheric delay are integrated to the proposed algorithm. The effectiveness of the proposed algorithms is verified via computer simulations, and real data experiments are also conducted based on both an X -band spaceborne SAR system, Taijing 4-01, and a Ka -band spaceborne SAR system, Luojia 2-01.
Lunar tidal deformation (LTD), characterized by the vertical (<inline-formula><tex-math notation="LaTeX">{{{\bm{h}}}_2}</tex-math></inline-formula>) and horizontal (<inline-formula><tex-math ...notation="LaTeX">{{{\bm{l}}}_2}</tex-math></inline-formula>) displacement Love numbers, is a key to deciphering the interior structure of the Moon. However, the small deformation amplitude of only up to 10 cm makes their measurements very challenging. In this article, we propose a novel method named Earth-based repeat-pass SAR interferometry (EBRP-InSAR) to measure the LTD and displacement Love numbers. We analyzed the potential and performance of EBRP-InSAR in detail based on the LTD model and existing planetary radar capabilities. The error budget and simulation results show that the relative measurement accuracy of LTD could be better than 2 mm. Furthermore, compared with lunar laser ranging (LLR) and lunar orbiter laser altimeter (LOLA), the two-pass EBRP-InSAR cannot only directly estimate <inline-formula><tex-math notation="LaTeX">{{{\bm{h}}}_2}</tex-math></inline-formula> but also <inline-formula><tex-math notation="LaTeX">{{{\bm{l}}}_2}</tex-math></inline-formula> with accuracies better than <inline-formula><tex-math notation="LaTeX">{{\text{10}}^{ - 3}}</tex-math></inline-formula> and<inline-formula><tex-math notation="LaTeX">{{\text{10}}^{ - 4}}</tex-math></inline-formula>, respectively, which is comparable to that of LLR and LOLA methods. In addition, through long-term time-series observations, it will be possible to assess the spatial inhomogeneity of LTD response to the forcing potential in the near side with time-series EBRP-InSAR. After spatial smoothing, a space variation as small as on the order of <inline-formula><tex-math notation="LaTeX">{{\text{10}}^{ - 4}}</tex-math></inline-formula> and <inline-formula><tex-math notation="LaTeX">{{\text{10}}^{ - 5}}</tex-math></inline-formula> in <inline-formula><tex-math notation="LaTeX">{{{\bm{h}}}_2}</tex-math></inline-formula> and <inline-formula><tex-math notation="LaTeX">{{{\bm{l}}}_2}</tex-math></inline-formula>, respectively, can be distinguished on the lunar near side. As another measurement technology independent of LLR and LOLA, the EBRP-InSAR is expected to explain the difference between the observations from LLR and LOLA and the modeled lunar interior structure, and first estimate the lunar horizontal displacement Love number.
► Design a setup for studying atmospheric corrosion by electrochemical methods.
► In situ study on atmospheric corrosion under adsorbed thin electrolyte layer. ► External electric field accelerates ...directed migration of Cl
− ions. ► External electric field accelerates localized corrosion of copper film in fact. ► Temperature accelerates atmospheric corrosion of copper film.
The effects of temperature and electric field on atmospheric corrosion behaviour of PCB-Cu under absorbed thin electrolyte layers were investigated by cathodic polarization and electrochemical impedance spectroscopy. Results indicate that the cathodic current density increases with increasing temperature, but decreases with increasing intensity of electric field. Electric field reduces the corrosion rate of PCB-Cu due to the aggressive ions migrating out from PCB-Cu electrode surface under the effect of electric field. When the ions can not freely migrate out from PCB-Cu electrode surface, local enrichment of aggressive ions under the electric field will cause serious localized corrosion of PCB-Cu.
Prolonged mechanical ventilation (MV) induces diaphragm dysfunction in patients in the intensive care units (ICUs). Our study aimed to explore the therapeutic efficacy of early rehabilitation therapy ...in patients with prolonged MV in the ICU.
Eighty eligible patients who underwent MV for > 72 h in the ICU from June 2019 to March 2020 were enrolled in this prospective randomised controlled trial. The patients were randomly divided into a rehabilitation group (n = 39) and a control group (n = 41). Rehabilitation therapy included six levels of rehabilitation exercises. Diaphragm function was determined using ultrasound (US).
Diaphragmatic excursion (DE) and diaphragm thickening fraction (DTF) were significantly decreased in all patients in both groups after prolonged MV (p < 0.001). The rehabilitation group had significantly higher DTF (p = 0.008) and a smaller decrease in DTF (p = 0.026) than the control group after 3 days of rehabilitation training. The ventilator duration and intubation duration were significantly shorter in the rehabilitation group than in the control group (p = 0.045 and p = 0.037, respectively). There were no significant differences in the duration of ICU stay, proportion of patients undergoing tracheotomy, and proportion of recovered patients between the two groups.
Early rehabilitation is feasible and beneficial to ameliorate diaphragm dysfunction induced by prolonged MV and advance withdrawal from the ventilator and extubation in patients with MV. Diaphragm US is suggested for mechanically ventilated patients in the ICU. Trial registration Chinese Clinical Trial Registry, ID: ChiCTR1900024046, registered on 2019/06/23.
The complex thermal history of the Moon leads to an unequal distribution of volcanic products between the lunar nearside and the farside. So far, no lunar materials have been sampled from the Moon's ...farside and no detailed properties of lunar regolith on the farside have been detected before. On January 3, 2019, Chang'E‐4 (CE‐4) touched down onto the Von Kármán crater on the Moon's farside. CE‐4 Lunar Penetrating Radar (LPR) onboard the Yutu‐2 rover is the first surface radar on the Moon's farside. Here we show the subsurface structure and properties of regolith materials at the landing region with LPR data during the first five lunar days. The thickness of lunar regolith is constrained as ∼12 m, much thicker than that at Chang'E‐3 (CE‐3) landing site, which is expected since CE‐3 landed on lunar maria. The relative permittivity of lunar surface (<30 cm) at CE‐4 landing region is identified to be 2.35 ± 0.20. The loss tangent and TiO2 + FeO content of the regolith materials layer (0–∼12 m) are constrained to be (4.4±0.5)×10−3 and 11.6±1.1 wt.%, respectively, much lower than those at CE‐3 landing site. It indicates that local surface materials possess less attenuation for radiowave, in accordance with the greater penetrating depth of CE‐4 LPR than that of CE‐3 LPR. Furthermore, the results also prove that the growth rate of lunar weathered regolith successively declines over time and the growth rate of lunar regolith on the Moon's farside may well be higher than that on the nearside due to the more frequent meteorite impacts.
Plain Language Summary
Lunar regolith (informally called the lunar soil) is the uppermost material on the lunar surface. It preserves vital clues about geology and impact history of the Moon. Although numerous missions to the Moon have landed on the nearside, so far, no lunar materials have been sampled from the Moon's farside. In 2019, China's Chang'E‐4 (CE‐4) spacecraft softly landed on the farside of the Moon for the first time and deployed its rover, Yutu‐2. The Lunar Penetrating Radar (LPR) onboard Yutu‐2 can transmit electromagnetic pulses to detect the lunar subsurface structure and properties of the regolith. The relative permittivity, loss tangent and TiO2 + FeO content of lunar regolith materials at landing site are constrained with LPR data in this paper. The results indicate that the farside may be bombarded more frequently, leading to different regolith accumulation rates on the lunar nearside versus farside.
Key Points
Detailed stratigraphy of lunar regolith on the Moon's farside is unveiled with Chang'E‐4 Lunar Penetrating Radar data
The dielectric properties and ilmenite content of regolith materials at the landing region are identified
The thickness and accumulated rate of lunar regolith at the landing region are constrained and analyzed
•A novel one-step method is developed for producing PEO/LDH coating.•PO43− in electrolyte and Al in AZ31 alloy are necessary species for the formation of Mg-Al LDH.•PEO/LDH composite coating provides ...enhanced corrosion resistance.•An Al- and Zn-enriched layer is formed at the alloy/coating interface during PEO.
In the present work, a novel one-step plasma electrolytic oxidation (PEO) method is developed for the formation of PEO/Mg-Al layered double hydroxide (LDH) composite coating on AZ31 Mg alloy. Through the control of electrolyte concentration, a Mg-Al LDH layer was formed on the surface of the resultant PEO coating. The corrosion properties of the composite coating were evaluated by electrochemical analysis, hydrogen evolution measurement and salt spraying testing, which exhibited improved corrosion resistance due to the presence of the Mg-Al LDH layer. This work provides a new strategy to take advantage of alloying elements in Mg alloys in PEO treatment to enhance corrosion resistance.
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