Fast and versatile electrostatic disc microprinting for piezoelectric elements.

Nanoparticles, films, and patterns are three critical piezoelectric elements with widespread applications in sensing, actuations, catalysis and energy harvesting. High productivity and large-area fabrication of these functional elements is still a significant challenge, let alone the control of their structures and feature sizes on various substrates. Here, we report a fast and versatile electrostatic disc microprinting, enabled by triggering the instability of liquid-air interface of inks. The printing process allows for fabricating lead zirconate titanate free-standing nanoparticles, films, and micro-patterns. The as-fabricated lead zirconate titanate films exhibit a high piezoelectric strain constant of 560 pm V-1, one to two times higher than the state-of-the-art. The multiplexed tip jetting mode and the large layer-by-layer depositing area can translate into depositing speeds up to 109 µm3 s-1, one order of magnitude faster than current techniques. Printing diversified functional materials, ranging from suspensions of dielectric ceramic and metal nanoparticles, to insulating polymers, to solutions of biological molecules, demonstrates the great potential of the electrostatic disc microprinting in electronics, biotechnology and beyond.

Active self-assembly of piezoelectric biomolecular films via synergistic nanoconfinement and in-situ poling.

Piezoelectric biomaterials have attracted great attention owing to the recent recognition of the impact of piezoelectricity on biological systems and their potential applications in implantable sensors, actuators, and energy harvesters. However, their practical use is hindered by the weak piezoelectric effect caused by the random polarization of biomaterials and the challenges of large-scale alignment of domains. Here, we present an active self-assembly strategy to tailor piezoelectric biomaterial thin films. The nanoconfinement-induced homogeneous nucleation overcomes the interfacial dependency and allows the electric field applied in-situ to align crystal grains across the entire film. The ß-glycine films exhibit an enhanced piezoelectric strain coefficient of 11.2 pm V-1 and an exceptional piezoelectric voltage coefficient of 252 × 10-3 Vm N-1. Of particular significance is that the nanoconfinement effect greatly improves the thermostability before melting (192 °C). This finding offers a generally applicable strategy for constructing high-performance large-sized piezoelectric bio-organic materials for biological and medical microdevices.

Microfluidic Biosensor Based on Molybdenum Disulfide (MoS2) Modified Thin-Core Microfiber for Immune Detection of Toxoplasma gondii.

Toxoplasma gondii (T. gondii) is a zoonotic parasite that is widely distributed and seriously endangers public health and human health. Therefore, accurate and effective detection of T. gondii is crucial. This study proposes a microfluidic biosensor using a thin-core microfiber (TCMF) coated with molybdenum disulfide (MoS2) for immune detection of T. gondii. The single-mode fiber was fused with the thin-core fiber, and the TCMF was obtained by arc discharging and flame heating. In order to avoid interference and protect the sensing structure, the TCMF was encapsulated in the microfluidic chip. MoS2 and T. gondii antigen were modified on the surface of TCMF for the immune detection of T. gondii. Experimental results showed that the detection range of the proposed biosensor for T. gondii monoclonal antibody solutions was 1 pg/mL to 10 ng/mL with sensitivity of 3.358 nm/log(mg/mL); the detection of limit was calculated to be 87 fg/mL through the Langmuir model; the dissociation constant and the affinity constant were calculated to be about 5.79 × 10-13 M and 1.727 × 1014 M-1, respectively. The specificity and clinical characteristics of the biosensor was explored. The rabies virus, pseudorabies virus, and T. gondii serum were used to confirm the excellent specificity and clinical characteristics of the biosensor, indicating that the proposed biosensor has great application potential in the biomedical field.

Green Fabrication of Freestanding Piezoceramic Films for Energy Harvesting and Virus Detection.

Most electronics such as sensors, actuators and energy harvesters need piezoceramic films to interconvert mechanical and electrical energy. Transferring the ceramic films from their growth substrates for assembling electronic devices commonly requires chemical or physical etching, which comes at the sacrifice of the substrate materials, film cracks, and environmental contamination. Here, we introduce a van der Waals stripping method to fabricate large-area and freestanding piezoceramic thin films in a simple, green, and cost-effective manner. The introduction of the quasi van der Waals epitaxial platinum layer enables the capillary force of water to drive the separation process of the film and substrate interface. The fabricated lead-free film, [Formula: see text] (BCZT), shows a high piezoelectric coefficient d33 = 209 ± 10 pm V-1 and outstanding flexibility of maximum strain 2%. The freestanding feature enables a wide application scenario, including micro energy harvesting, and covid-19 spike protein detection. We further conduct a life cycle analysis and quantify the low energy consumption and low pollution of the water-based stripping film method.

Balancing Volmer Step by Superhydrophilic Dual-Active Domains for Enhanced Hydrogen Evolution.

The reaction kinetics of hydrogen evolution reaction (HER) is largely determined by balancing the Volmer step in alkaline media. Bifunctionality as a proposed strategy can divide the work of water dissociation and intermediates (OH* and H*) adsorption/desorption. However, sluggish OH* desorption plagues water re-adsorption, which leads to poisoning effects of active sites. Some active sites may even directly act as spectators and do not participate in the reaction. Furthermore, the activity comparison under approximate nanostructure between bifunctional effect and single-exposed active sites is not fully understood. Here, a facile three-step strategy is adopted to successfully grow molybdenum disulfide (MoS2 ) on cobalt-containing nitrogen-doped carbon nanotubes (Co-NCNTs), forming obvious dual active domains. The active sites on domains of Co-NCNTs and MoS2  and the tuned electronic structure at the heterointerface trigger the bifunctional effect to balance the Volmer step and improve the catalytic activity. The HER driven by the bifunctional effect can significantly optimize the Gibbs free energy of water dissociation and hydrogen adsorption, resulting in fast reaction kinetics and superior catalytic performance. As a result, the Co-NCNTs/MoS2  catalyst outperforms other HER electrocatalysts with low overpotential (58 and 84 mV at 10 mA cm-2  in alkaline and neutral conditions, respectively), exceptional stability, and negligible degradation.

Improving Relative Permittivity and Suppressing Dielectric Loss of Triboelectric Layers for High-Performance Wearable Electricity Generation.

High relative permittivity and low dielectric loss are two desired parameters of a triboelectric layer to enhance its mechanical-to-electrical energy conversion efficiency in a triboelectric nanogenerator (TENG). However, the elevated permittivity of the triboelectric layer is always accompanied by increasing dielectric loss, limiting further improvement or even reducing the electrical output. Herein, we report a method for improving the relative permittivity and suppressing the dielectric loss of the triboelectric layer via nanoscale design at the particle-polymer interface. When incorporated with 2 wt % Ag@C, the triboelectric-layer-enhanced TENG (TLE-TENG) presents a 2.6-fold increment in relative permittivity and a 302% current enhancement. An instantaneous peak power density of 1.22 W m-2, an excellent pressure sensitivity of 90.95 V kPa-1, and an optimized sheet resistance (∼0.14 Ω/sq) are attributes of this greatly enhanced device. Such improvements bode well for the implementation of these enhancing strategies to help position TLE-TENGs as pervasive and sustainable power sources and active self-powered sensors in the era of the Internet of Things.

Self-charging electrostatic face masks leveraging triboelectrification for prolonged air filtration.

Electrostatic adsorption is an important complement to the mechanical filtration for high-efficiency air filtering. However, the electrostatic charge decays with time, especially in humid conditions. In this work, a self-charging air filter is presented to capture airborne particles in an efficient and long-lasting manner without the need of external power sources. Leveraging the triboelectric effect between the electrospun poly(vinylidene fluoride) nanofiber film and nylon fabric, the self-charging air filter-based mask excited by breathing can continuously replenish electrostatic charges. As a result, its effective lifespan is up to 60 hours (including 30 hours of wearing), with a minimum filtration efficiency of 95.8% for 0.3-µm particles. The filtration efficiency and lifespan are significantly higher than those of a commercial surgical mask. Furthermore, we uncover the quantitative relation between filtration efficiency and surface electrostatic potential. This work provides an effective strategy to significantly prolong the electrostatic adsorption efficacy for high-performance air-filtering masks.

Van der Waals Exfoliation Processed Biopiezoelectric Submucosa Ultrathin Films.

Piezoelectric biomaterials have attracted significant attention due to the potential effect of piezoelectricity on biological tissues and their versatile applications. However, the high cost and complexity of assembling and domain aligning biomolecules at a large scale, and the disordered arrangement of piezoelectric domains as well as the lack of ferroelectricity in natural biological tissues remain a roadblock toward practical applications. Here, utilizing the weak van der Waals interaction in the layered structure of small intestinal submucosa (SIS), a van der Waals exfoliation (vdWE) process is reported to fabricate ultrathin films down to the thickness of the effective piezoelectric domain. Based on that, the piezoelectric property is revealed of SIS stemming from the collagen fibril, with piezoelectric coefficients up to 4.1 pm V-1 and in-plane polarization orientation parallel to the fibril axis. Furthermore, a biosensor based on the vdWE-processed SIS film with an in-plane electrode is demonstrated that produces open-circuit voltages of ≈250 mV under the cantilever vibration condition. The vdWE method shows great potential in facilely fabricating ultrathin films of soft tissues and biosensors.

[Magnetic resonance and magnetoelectric therapy combined with Danhong Tongjing Prescription for the treatment of CP/CPPS and its effects on secretory IgA, vascular cell adhesion molecule-1 and interleukin-8].

OBJECTIVE: To investigate the therapeutic effect of magnetic resonance and magnetoelectric therapy (MRMT) combined with oral Danhong Tongjing Prescription (DTP) on chronic prostatitis / chronic pelvic pain syndrome (CP/CPPS) and the changes in the levels of cytokine-secretory IgA (sIgA), vascular cell adhesion molecule-1 (VCAM-1) and interleukin-8 (IL-8) after treatment. METHODS: Totally 200 patients with CP/CPPS of the qi stagnation and blood stasis type were randomly divided into three groups to receive MRMT + DTP (n = 68), MRMT (n = 67) and DTP (n = 65), respectively, all for 12 weeks. After treatment, we compared the total effectiveness rate, patients' scores on NIH-CPSI and traditional Chinese medicine (TCM) syndrome, and the expressions of sIgA, VCAM-1 and IL-8 in the EPS among the three groups of the patients. RESULTS: After treatment, the patients in the MRMT + DTP group, compared with those in the MRMT and DTP groups, showed a significantly higher total effectiveness rate (86.76% vs 79.10% and 78.46%, P < 0.05 and P < 0.01) and lower scores on pain or discomfort (4.61 ± 2.37 vs 5.86 ± 3.26 and 6.94 ± 2.25 P < 0.01), abnormal urination symptoms (2.98 ± 1.75 vs 3.85 ± 2.01 and 3.94 ± 1.95) and quality of life (3.26 ± 1.87 vs 4.54 ± 2.13 and 4.69 ± 1.72). There were statistically significant differences in the total NIH-CPSI scores among the three groups (10.64 ± 5.91 vs 4.59 ± 6.87 vs 15.54 ± 5.76, P < 0.05). The MRMT + DTP group also exhibited a remarkably lower TCM syndrome score than the MRMT and DTP groups (5.56 ± 3.42 vs 7.37 ± 4.57 and 8.16 ± 3.65, P < 0.05). Compared with the baseline, the expressions sIgA, VCAM-1 and IL8 were all markedly decreased after treatment in the MRMT + DTP (Z = －7.170, Z = －7.182, Z = －7.18), MRMT (Z = －6.802, Z = －6.973, Z = －6.768) and DTP groups (Z = －5.963, Z = －6.990 Z = －5.618) (P < 0.05), even more significantly in the former than in the latter two groups (P < 0.05). CONCLUSION: Magnetic resonance and magnetoelectric therapy combined with Danhong Tongjing Prescription has a good therapeutic effect on CP/CPPS of the qi stagnation and blood stasis type, probably by regulating sIgA, VCAM-1, IL-8 and other cytokines, activating the function of the immune system, inhibiting inflammation, and promoting the absorption of local inflammatory substances.

Atypical enhanced computed tomography signs of pancreatic cancer and its differential diagnosis from autoimmune pancreatitis.

BACKGROUND: To analyze the atypical enhanced computed tomography (CT) signs of pancreatic cancer (PC) and compare them with those of autoimmune pancreatitis (AIP) to explore the differential diagnosis value of CT. METHODS: The clinical data of 36 AIP (AIP group) and 38 PC patients (PC group), who were admitted to our hospital from January 2013 to June 2020 and confirmed by surgical biopsy or hormone therapy, were retrospectively analyzed. Participants in both groups were examined by CT, the imaging signs of the 2 groups were analyzed, and the results of CT examination were compared. RESULTS: In the PC group, the density of the lesions on the CT scan was mostly reduced, the pancreas was not swollen, and the kidneys were not involved. The bile duct wall was thickened with a sausage-like appearance, enveloped edges were rare, blood vessels were invaded, lymph nodes were enlarged, and the pancreatic duct was truncated. The findings of the AIP group were the opposite. The difference in the proportion of participants with the above-mentioned CT features between the 2 groups was statistically significant (P<0.05). The shape of the lesions in the AIP group was mainly elongated, of uneven density, and the density of enhanced scanning was medium to high. The predominant shape of the lesions in PC participants was spherical, and the density was uniform. The enhanced scan was mainly low-density. The difference in shape and density between the 2 groups was also statistically significant (P<0.05). The CT values of the plain scan, intravenous phase, and delayed phase in the AIP group were significantly higher than those in the PC group (P<0.05). CONCLUSIONS: The imaging signs of AIP and PC overlap. Examination with CT is of great value in the differential diagnosis between AIP and PC. Familiarity with and mastery of the CT signs of AIP and PC can help to improve the accuracy of clinical diagnosis and provide a reliable basis for patients' follow-up treatment.

Accelerating ion diffusion with unique three-dimensionally interconnected nanopores for self-membrane high-performance pseudocapacitors.

Herein, a unique three-dimensionally interconnected nanoporous structure (3-D INPOS) pseudocapacitor electrode, which possesses a large surface area, an efficient electron and ion transport, together with a remarkable structural stability, has been constructed via soft anodization of an aluminum alloy, cost-effective ultrasonic spray pyrolysis (USP)-assisted deposition of fluorine-doped tin oxide (FTO), and controllable electrochemical deposition of nanostructured manganese dioxide (MnO2). Taking the advantage of large surface area, the as-built 3-D INPOS pseudocapacitor electrode exhibits the highest areal capacitance of 540 mF cm-2 and a volumetric capacitance of 135 F cm-3, which is 53% higher than that achieved from the conventional 3-D nanopore pseudocapacitor electrode and 17.6 times higher than that of the planar electrode. More interestingly, the unique 3-D interconnected structure offers an unrestricted space for the diffusion of electrolyte ions. Thus, the 3-D INPOS electrode achieves a higher rate capability than the 3-D nanopore electrode. As a proof of concept, a symmetric self-membrane pseudocapacitor device was constructed by simply stacking two pieces of the 3-D INPOS electrodes. Without an added separator, the device possesses a largely reduced dead volume and achieves the highest volumetric capacitance of 28.9 F cm-3 and a specific energy of 2.36 mW h cm-3. The largely enhanced capacitance, rate capability, and specific energy certainly make the 3-D INPOS an ideal architecture for the fabrication of high-performance pseudocapacitors.

[The value of gastric bare area, left adrenal gland and perirenal space involvement in predicting complications of acute pancreatitis].

OBJECTIVE: To investigate CT findings and incidence rate of gastric bare area involvement (GBAI), left adrenal gland involvement (LAGI) and perirenal space involvement (PSI) in acute pancreatitis, and to also explore the value of these appearances in predicting complications and mortality of patients. METHODS: CT imaging data of 575 patients with AP diagnosed by clinic from October 2009 to April 2011 were analyzed retrospectively. There were 339 male and 236 female patients, aging from 16 to 93 years with a mean of (51 ± 16) years. Involvement with or without gastric bare area, left adrenal gland, perirenal space were focused, and the relationship were analyzed between these CT findings and complications and mortality of patients. RESULTS: Among 167 patients (29.0%) with GBAI, 132 had complications and 16 died. The sensitivity and specificity of GBAI for predicting complications were 45.4% and 87.7%, respectively, and 84.2%and 72.8% for predicting mortality. In all 107 patients (18.6%) with LAGI, 81 had complications and 18 died. The sensitivity and specificity of LAGI for predicting complications were 27.8% and 90.8%, respectively, and 94.7% and 84.0% for predicting mortality. Among 335 patients (58.3%) with PSI, 201 had complications and 19 died. The sensitivity and specificity of PSI for predicting complications were 69.1% and 52.8%, respectively, and 100% and 43.2% for predicting mortality. Of all patients, 210 (36.5%) owned two or more positive CT findings among GBAI, LAGI, and PSI. One hundred ninety-eight of these patients had complications and 19 died, that predicted the sensitivity and specificity for complications were 68.0% and 95.8%, respectively, and 100% and 65.6% for mortality. The risk of complications in the patients with GBAI or LAGI was increased than normal gastric bare area or left adrenal gland 5.9 or 3.8 times respectively, and the risk of death was improved 14.3 or 94.5 times respectively. The risk of complications in those patients with two or more positive findings increased by 48.3 times. By analyzing receiver operating characteristic (ROC) curve, the combination of GBAI, LAGI, and PSI was the best way to predict the complications of AP. The area under the ROC was 0.819. CONCLUSIONS: The CT imaging could effectively indicate the signs of GBAI, LAGI and PSI of AP. The GBAI. LAGI and PSI were related with the severity and prognosis of AP, and these findings could be clinical indicators for evaluating prognosis of AP.

[Comparison of coronary angiography with myocardial perfusion imaging in assessment of functionally relevant coronary artery lesion].

OBJECTIVE: To evaluate the accuracy of dual-source CT coronary angiography (DSCTCA) for the depiction of functionally relevant coronary artery lesion(FRCAL), by using myocardial perfusion imaging (MPI) with single photon emission computed tomography (SPECT). METHODS: DSCTCA, (99)Tc(m)-MIBI SPECT myocardial perfusion imaging (MPI) and conventional coronary angiography (CCA) were performed in 59 patients with clinical suspected CAD. Coronary artery diameter narrowing of 50% or greater at DSCTCA was defined as stenosis and was compared with MPI findings. CCA was served as a reference standard for DSCTCA. RESULTS: (1) Agreement between DSCTCA and CCA was good (kappa = 0.93 for patient-based analysis, Kappa = 0.88 for vessel-based analysis). (2) DSCTCA revealed stenoses in 86 segments corresponding to 60 arteries in 34 patients. (3) MPI revealed 19 reversible, 21 partially reversible, and 5 fixed defects in 25 patients. (4) About 65.0% (39/60) of all the narrowed coronary arteries were determined to be FRCAL. Sensitivity, specificity, accuracy, positive predictive values and negative predictive values, respectively, of DSCTCA in the detection of all MPI defects were 92.0%, 67.6%, 78.0%, 67.6% and 92.0% on a per-patient basis and 86.7%, 89.0%, 88.6%, 65.0% and 96.6% on a per-artery basis. (5) ROC analysis showed that predictive value of DSCTCA in FRCAL was similar with those of CCA (AUCs = 0.80, 0.82). CONCLUSIONS: DSCTCA can evaluate FRCAL indirectly. When DSCTCA results are negative, it can help ruled out patients with FRCAL. The positive DSCTCA results should combine MPI in predictor of myocardial ischemia.

[Clinical applications of routine subtraction and dual-energy subtraction cervical arteries computed tomographic angiography for cervical arteries imaging].

OBJECTIVE: To compare with the clinical applications of routine-subtraction and dual-energy subtraction cervical arteries computed tomographic angiography (CTA) for cervical arteries imaging. METHODS: Scanning was performed in 45 patients with clinically suspected cervical arteries disease with dual-source CT. The data of two different energy were collected only at one scanning. The data post processing include: conventional bone-removal digital subtraction (routine-subtraction) was performed with plain and 80 kV enhanced scanning. Volume render (VR) and maximum intensity projection (MIp) reconstruction were finished. Direct bone-removal digital subtraction (dual-energy subtraction) was performed with 80 and 140kV enhanced scanning that have different energy, and saving the data of subtraction. VR and MIp reconstruction were finished. The image quality, which was divided into four grades, was compared between these two groups. The effective radiation dose was also compared. RESULTS: For normal vessels, no abnormality was found in 24 of 45 cases, with the common carotid artery and its branches clearly displayed with both two methods. The image quality was not significantly different between dual-energy subtraction CTA and routine subtraction CTA (P>0.05) . For stenotic vessels, 45 stenotic vessels in 21 cases were clearly displayed clearly with both two methods (P>0.05) . The effective radiation dose was decreased by 17.3 % for dual-energy subtraction CTA when compared with routine-subtraction CTA (P<0.01) . CONCLUSIONS: Both routine-subtraction and dual-energy subtraction CTA can clearly display normal and stenotic vessels. The radiation exposure dose is relatively lower in dual-energy CTA. The dual-energy subtraction CTA has better effectiveness when used for non-cooperation patients.