Intelligent Optimization Method of Piezoelectric Ejection System Design Based on Finite Element Simulation and Neural Network.

This study describes an intelligent method for modeling and optimization of piezoelectric ejection system design for additive manufacturing. It is a combination of neural network (NN) techniques and finite element simulation (FES) that allows designing each parameter of a piezoelectric ejection system faster and more reliably than conventional methods. Using experimental and literature data, a FE model of the droplet ejection process was developed and validated to predict two indexes of droplet ejection behavior (DEB): jetting velocity and droplet diameter. Two artificial neural network (ANN) models based on feed-forward back propagation were developed and optimized by genetic algorithm (GA). A database was established by FE calculations, and the models were trained to establish the relationship between the piezoelectric ejection system design input parameters and each DEB indicator. The results show that both NN models can independently predict the droplet jetting velocity and droplet diameter values from the training and testing data with high accuracy to determine the optimal piezoelectric ejection system design. Finally, the accuracy of the prediction results of the FES and ANN-GA models was verified experimentally. It was found that the errors between the predicted and experimental results were 4.48% and 3.18% for the jetting velocity and droplet diameter, respectively, verifying that the optimization method is reliable and robust for piezoelectric ejection system design optimization.

The Therapeutic Effect of Contezolid in Complex Intra-Abdominal Infections.

Purpose: In this paper, we observed the use of contezolid in patients with complex intra-abdominal infections in the intensive care unit of the Hepatobiliary Surgery department at the Chinese PLA General Hospital. Patients and Methods: The study collected data on complex intra-abdominal infections patients who received the antibiotic contezolid between January 2022 and April 2023. Results: Contezolid was administered to 12 patients, including 8 with severe acute pancreatitis, 3 with intra-abdominal infections following abdominal surgery, and 1 with complicated intra-abdominal infection after trauma. Gram-positive bacteria, such as Enterococcus faecium, Enterococcus casseliflavus, Staphylococcus capitis, and Staphylococcus haemo-lytica, were detected in 11 patients. All patients who received contezolid had previously been treated with other anti-Gram-positive agents, including linezolid for 9 patients, teicoplanin for 6 patients, and vancomycin for 3 patients. The treatment with contezolid began 20.0 (15.0, 34.5) days after admission and lasted for 8.0 (6.0, 10.0) days. At the end of the treatment, the patients' body temperature showed a significant decrease. After concomitant therapy, IL-6 levels decreased, and platelet count increased. Conclusion: Contezolid has shown potential in treating complex intra-abdominal infections caused by Gram-positive bacteria by reducing fever and inflammatory response.

Research on High-Precision Measurement Method for Small-Size Gears with Small-Modulus.

Small-modulus gears, which are essential for motion transmission in precision instruments, present a measurement challenge due to their minuscule gear gaps. A high-precision measurement method under the influence of positioning errors is proposed, enabling precise evaluation of the machining quality of small-modulus gears. Firstly, a compound measurement platform for small-modulus gears is developed. Using a 3D model of the measurement system, the mathematical relationships governing motion transmission between various components are analyzed. Secondly, the formation mechanism of gear positioning error is revealed and its important influence on measurement accuracy is discussed. An optimization method for spatial coordinate transformation matrices under positioning errors of gears is proposed. Thirdly, the study focuses on small-sized gears with a modulus of 0.1 mm and a six-level accuracy. Based on the aforementioned measurement system, the tooth profile measurement points are collected in the actual workpiece coordinate system. Then, gear error parameters are extracted based on the established models for tooth profile deviation and pitch deviation. Finally, the accuracy and effectiveness of the proposed measurement method are verified by comparing the measurement results of the P26 gear measuring center.

Mapping and monitoring dense non-aqueous phase liquid source zone by fused surface and cross-borehole electrical resistivity tomography.

Effective characterization of dense non-aqueous phase liquid (DNAPL) source zones is crucial for remediating polluted sites. DNAPL often reside as residuals or pools within high-permeability lenses and above impermeable layers due to soil heterogeneity, gravity, and capillary barriers. Given the high cost of drilling, electrical resistivity tomography (ERT) techniques-including surface ERT and cross-borehole ERT, are commonly used for DNAPL source zone mapping and monitoring. However, the low spatial resolution of ERT increases uncertainty in source zone investigations. This study proposes a method for improving DNAPL mapping and monitoring by fusing surface and cross-borehole ERT data. Sandbox experiments were conducted to simulate a heterogeneous DNAPL source zone, employing both ERT methods for static mapping and dynamic monitoring. Reflective light imaging (RLM) was used to visualize DNAPL migration and provide saturation data, allowing for the quantification of ERT's effectiveness in characterizing DNAPL distribution. The results indicate that individual ERT methods face significant challenges in DNAPL source zone mapping due to background interference. Surface ERT alone tends to underestimate the extent of deeper DNAPL source zones. However, fusing surface and cross-borehole ERT results in a complementary enhancement of vertical spatial resolution, thereby improving the characterization of DNAPL source zones. The fusion of static and time-lapse ERT data substantially enhances DNAPL source zone mapping and monitoring capabilities. By calculating the ratio of the ERT-monitored area to the actual area using resistivity change contours (5 %, 10 %, 15 %), it was found that fusing surface and cross-borehole ERT data improved monitoring resolution by 50.48 % compared to surface ERT alone and by 22.95 % compared to cross-borehole ERT. Principal component analysis (PCA) was effective in fusing time-lapse data, while the weighted average method (WAM) outperformed PCA for static resistivity data fusion.

Performance-Degradation Analysis of the Planetary Roller Screw Mechanism under Multi-Factor Coupling Effects.

The performance-degradation pattern of the planetary roller screw mechanism (PRSM) is difficult to predict and evaluate due to a variety of factors. Load-carrying capacity, transmission accuracy, and efficiency are the main indicators for evaluating the performance of the PRSM. In this paper, a testing device for the comprehensive performance of the PRSM is designed by taking into account the coupling relationships among temperature rise, vibration, speed, and load. First, the functional design and error calibration of the testing device were conducted. Secondly, the PRSM designed in the supported project was taken as the research object to conduct degradation tests on its load-bearing capacity and transmission accuracy and analyze the changes in transmission efficiency. Third, the thread profile and wear condition were scanned and inspected using a universal tool microscope and an optical microscope. Finally, based on the monitoring module of the testing device, the vibration status during the PRSM testing process was collected in real time, laying a foundation for the subsequent assessment of the changes in the performance state of the PRSM. The test results reveal the law of performance degradation of the PRSM under the coupled effects of temperature, vibration, speed, and load.

Case report: [18F]FAPI-42 PET/CT visualize primary adenoid cystic carcinoma not detected by [18F]FDG.

Adenoid cystic carcinoma (ACC) is a rare salivary gland cancer. Still, its growth and invasion progress is slow, and its hematogenous metastasis is ACC's most common distant metastasis. Because of the broad expression and low background uptake of fibroblast activation protein (FAP) in tumor stroma, FAPI is considered another potential tracer of ACC in addition to FDG. In this case, we report a patient who was diagnosed with metastatic ACC liver cancer by fine needle aspiration biopsy (FNAB) and underwent PET/CT examination of [18F]FDG and [18F]FAPI-42 to find the primary cancer lesion. Finally, the primary cancer lesion was found in the left submandibular gland and was pathologically confirmed as ACC after resection.

Groundwater Cr(VI) contamination and remediation: A review from 1999 to 2022.

Hexavalent chromium (Cr(VI)) contamination of groundwater has traditionally been an environmental issue of great concern due to its bioaccumulative and highly toxic nature. This paper presents a review and bibliometric analysis of the literature on the interest area "Cr(VI) in groundwater" published in the Web of Science Core Collection from 1999 to 2022. First, information on 203 actual Cr(VI)-contaminated groundwater sites around the world was summarized, and the basic characteristics of the sources and concentrations of contamination were derived. 68.95% of the sites were due to human causes and 56.43% of these sites had Cr(VI) concentrations in the range of 0-10 mg/L. At groundwater sites with high Cr(VI) contamination due to natural causes, 75.00% of the sites had Cr(VI) concentrations less than 0.2 mg/L. A total of 936 papers on "Cr(VI) in groundwater" were retrieved for bibliometric analysis: interest in research on Cr(VI) in groundwater has grown rapidly in recent years; 59.4% of the papers were published in the field of environmental sciences. A systematic review of the progress of studies on the Cr(VI) removal/remediation based on reduction, adsorption and biological processes is presented. Out of 666 papers on Cr(VI) removal/remediation, 512, 274, and 75 papers dealt with the topics of reduction, adsorption, and bioremediation, respectively. In addition, several studies have demonstrated the potential applicability of natural attenuation in the remediation of Cr(VI)-contaminated groundwater. This paper will help researchers to understand and investigate methodological strategies to remove Cr(VI) from groundwater in a more targeted and effective manner.

Experimental research on the transport-transformation of organic contaminants under the influence of multi-field coupling at a site scale.

Organic-contaminated shallow aquifers have become a global concern of groundwater contamination, yet little is known about the coupled effects of hydrodynamic-thermal-chemical-microbial (HTCM) multi-field on organic contaminant transport and transformation over a short time in aquifers. Therefore, this study proposed a quick and efficient field experimental method for the transport-transformation of contaminants under multi-field coupling to explore the relationship between organic contaminants (total petroleum hydrocarbon (TPH), polycyclic aromatic hydrocarbons (PAHs), benzene-toluene-ethylbenzene-xylene (BTEX) and phthalates acid esters (PAEs)) and multi-field factors. The results showed that hydrodynamics (affecting pH, p < 0.001) and temperature (affecting dissolved oxygen, pH and HCO3-, p < 0.05) mainly affected the organic contaminants indirectly by influencing the hydrochemistry to regulate redox conditions in the aquifer. The main degradation reactions of the petroleum hydrocarbons (TPH, PAHs and BTEX) and PAEs in the aquifer were sulfate reduction and nitrate reduction, respectively. Furthermore, the organic contamination was directly influenced by microbial communities, whose spatial patterns were shaped by the combined effects of the spatial pattern of hydrochemistry (induced by the organic contamination pressure) and other multi-field factors. Overall, our findings imply that the spatiotemporal patterns of organic contaminants are synergistically regulated by HTCM, with distinct mechanisms for petroleum hydrocarbons and PAEs.

Solid self-emulsifying casein carrier for the improvement on the oral bioavailability of simvastatin.

Simvastatin (SV) is a statin drug that can effectively control cholesterol and prevent cardiovascular diseases. However, SV is water-insoluble, and poor oral bioavailability (<5 %). Solid self-emulsifying carrier system is more stable than liquid emulsions, facilitating to improve the solubility and bioavailability of poorly soluble drugs. In the present study, a solid self-emulsifying carrier stabilized by casein (Cas-SSE) was successfully used to load SV to improve its solubility in water, by formulation selection and emulsification process optimization. Compared with oral tablets, the release of SV from Cas-SSE was significantly enhanced in artificial intestinal fluid. Furthermore, everted gut sac experiments indicated some water-soluble dispersing agents such as hydroxyethyl starch (HES), were not conducive to drug absorption. Pharmacokinetic studies suggested Cas-SSE without dispersing agent has much higher relative bioavailability (184.1 % of SV and 284.5 % of simvastatin acid) than SV tablet. The present work suggests Cas-SSE is a promising drug delivery platform with good biocompatibility for improving oral bioavailability of poorly water-soluble drugs.

Repurposing lansoprazole to alleviate metabolic syndrome via PHOSPHO1 inhibition.

Drug repurposing offers an efficient approach to therapeutic development. In this study, our bioinformatic analysis first predicted an association between obesity and lansoprazole (LPZ), a commonly prescribed drug for gastrointestinal ulcers. We went on to show that LPZ treatment increased energy expenditure and alleviated the high-fat diet-induced obesity, insulin resistance, and hepatic steatosis in mice. Treatment with LPZ elicited thermogenic gene expression and mitochondrial respiration in primary adipocytes, and induced cold tolerance in cold-exposed mice, suggesting the activity of LPZ in promoting adipose thermogenesis and energy metabolism. Mechanistically, LPZ is an efficient inhibitor of adipose phosphocholine phosphatase 1 (PHOSPHO1) and produces metabolic benefits in a PHOSPHO1-dependent manner. Our results suggested that LPZ may stimulate adipose thermogenesis by inhibiting the conversion of 2-arachidonoylglycerol-lysophosphatidic acid (2-AG-LPA) to 2-arachidonoylglycerol (2-AG) and reduce the activity of the thermogenic-suppressive cannabinoid receptor signaling. In summary, we have uncovered a novel therapeutic indication and mechanism of LPZ in managing obesity and its related metabolic syndrome, and identified a potential metabolic basis by which LPZ improves energy metabolism.

New insights into long-lasting Cr(VI) removal from groundwater using in situ biosulfidated zero-valent iron with sulfate-reducing bacteria.

Sulfidation enhances the reactivity of zero-valent iron (ZVI) for Cr(VI) removal from groundwater. Current sulfidation methods mainly focus on chemical and mechanical sulfidation, and there has been little research on biosulfidation using sulfate-reducing bacteria (SRB) and its performance in Cr(VI) removal. Herein, the ability of the SRB-biosulfidated ZVI (SRB-ZVI) system was evaluated and compared with that of the Na2S-sulfidated ZVI system. The SRB-ZVI system forms a thicker and more porous FeSx layer than the Na2S-sulfidated ZVI system, resulting in more sufficient sulfidation of ZVI and a 2.5-times higher Cr(VI) removal rate than that of the Na2S-sulfidated ZVI system. The biosulfidated-ZVI granules and FeSx suspension are the major components of the SRB-ZVI system. The SRB-ZVI system exhibits a long-lasting (11 cycles) Cr(VI) removal performance owing to the regeneration of FeSx. However, the Na2S-sulfidated ZVI system can perform only two Cr(VI) removal cycles. SRB attached to biosulfidated-ZVI can survive in the presence of Cr(VI) because of the protection of the biogenic porous structure, whereas SRB in the suspension is inhibited. After Cr(VI) removal, SRB repopulates in the suspension from biosulfidated-ZVI and produce FeSx, thus providing conditions for subsequent Cr(VI) removal cycles. Overall, the synergistic effect of SRB and ZVI provides a more powerful and environmentally friendly sulfidation method, which has more advantageous for Cr(VI) removal than those of chemical sulfidation. This study provides a visionary in situ remediation strategy for groundwater contamination using ZVI-based technologies.

Effect of Interfacial Action on the Generation and Transformation of Reactive Oxygen Species in Tripolyphosphate-Enhanced Heterogeneous Fe3O4/O2 Systems.

It has been reported that tripolyphosphate (TPP) can enhance the oxygenation of natural Fe(II)-containing minerals to produce reactive oxygen species (ROS). However, the molecular structure of the TPP-Fe(II) mineral surface complex and the role of this complex in the generation and transformation of ROS have not been fully characterized. In the present study, a heterogeneous magnetite (Fe3O4)/O2/TPP system was developed for the degradation of p-nitrophenol (PNP). The results showed that the addition of TPP significantly accelerated the removal of PNP in the Fe3O4/O2 system and extended the range of effective pH to neutral. Experiments combined with density functional theory calculations revealed that the activation of O2 mainly occurs on the surface of Fe3O4 induced by a structural Fe(II)-TPP complex, where the generated O2•- (intermediate active species) can be rapidly converted into H2O2, and then the •OH generated by the Fenton reaction is released into the solution. This increases the concentration of •OH produced and the efficiency of •OH produced relative to Fe(II) consumed, compared with the homogeneous system. Furthermore, the binding of TPP to the surface of Fe3O4 led to stretching and even cleavage of the Fe-O bonds. Consequently, more Fe(II)/(III) atoms are exposed to the solvation environment and are available for the binding of active O2 and O2•-. This study demonstrates how common iron minerals and O2 in the natural environment can be combined to yield a green remediation technology.

Self-Catalyzed Hydrogenated Carbon Nano-Onions Facilitates Mild Synthesis of Transparent Nano-Polycrystalline Diamond.

Transparent nano-polycrystalline diamond (t-NPD) possesses superior mechanical properties compared to single and traditional polycrystalline diamonds. However, the harsh synthetic conditions significantly limit its synthesis and applications. In this study, a synthesis routine is presented for t-NPD under low pressure and low temperature conditions, 10 GPa, 1600 °C and 15 GPa, 1350 °C similar with the synthesis condition of organic precursor. Self-catalyzed hydrogenated carbon nano-onions (HCNOs) from the combustion of naphthalene enable synthesis under nearly industrial conditions, which are like organic precursor and much lower than that of graphite and other carbon allotropes. This is made possible thanks to the significant impact of hydrogen on the thermodynamics, as it chemically facilitates phase transition. Ubiquitous nanotwinned structures are observed throughout t-NPD due to the high concentration of puckered layers and stacking faults of HCNOs, which impart a Vickers hardness about 140 GPa. This high hardness and optical transparency can be attributed to the nanocrystalline grain size, thin intergranular films, absence of secondary phase and pore-free features. The facile and industrial-scale synthesis of the HCNOs precursor, and mild synthesis conditions make t-NPD suitable for a wide range of potential applications.

3D-printed scaffold harboring copper ions combined with near-infrared irradiation for local therapy of cancer.

Cancer is a major health threat and a leading cause of human death worldwide. Surgical resection is the primary treatment for most cancers; however, some patients develop locoregional recurrence. Here, we developed an in situ cancer therapeutic system aimed to locally treat cancer and prevent postoperative recurrence. A functional scaffold, based on alginate/gelatin and crosslinked with copper ions, was fabricated by 3D printing and showed an excellent photothermal effect under near-infrared (NIR) irradiation. The combination of copper ions and NIR effectively killed thyroid cancer cells and patient-derived organoids, indicating a synergetic and broad-spectrum antitumor effect on thyroid cancer through the chemo-photothermal therapy. This implantable stent is designed to provide effective treatment in the vicinity of the tumor site and can be degraded without secondary surgery. The copper-loaded hydrogel scaffold may be a potential candidate for local cancer treatment and pave the way for precise and effective cancer therapy.

Time-varying encounter angle trajectory tracking control of unmanned surface vehicle based on wave modeling.

In this note, a wave simulation method based on the wave spectrum is proposed, and the wave simulation is transformed into external interference to verify the necessity of using variable encounter angle real wave interference. Firstly, A wave simulation method based on wave spectrum and equidistant method is proposed and demonstrated. Secondly, wave modeling is transformed into interference force related to the encounter angle by fully considering the real marine environment. Furthermore, a trajectory tracking controller with variable encounter angles and the actual sea state is designed using the disturbance modeling method. Finally, the necessity and authenticity of considering varying encounter angles and real sea conditions in the motion control of unmanned surface vehicles (USVs) are proved by simulation.

Performance Study of Piezoelectric Injection System Based on Finite Element Simulation.

This paper presents a performance prediction method for piezoelectric injection systems, based on finite element simulations. Two indexes representing the system performance are proposed: jetting velocity and droplet diameter. By combining Taguchi's orthogonal array method and finite element simulation (FES), a finite element model of the droplet injection process, with different parameter combinations, was established. The two performance indexes, jetting velocity and droplet diameter, were accurately predicted, and their variation with time were investigated. Finally, the accuracy of the predicted results of the FES model was verified by experiments. The errors of the predicted jetting velocity and droplet diameter were 3.02% and 2.20%, respectively. It is verified that the proposed method has better reliability and robustness than the traditional method.

Preparation and Properties of High-Temperature-Resistant, Lightweight, Flexible Polyimide Foams with Different Diamine Structures.

Polyimide foam (PIF) is a rising star in high-end applications such as aerospace thermal insulation and military sound absorption. However, the basic rule on molecular backbone design and uniform pore formation of PIF still need to be explored. In this work, polyester ammonium salt (PEAS) precursor powders are synthesized between alcoholysis ester of 3, 3', 4, 4'-benzophenone tetracarboxylic dianhydride (BTDE) and aromatic diamines with different chain flexibility and conformation symmetry. Then, a standard "stepwise heating" thermo-foaming approach is used to prepare PIF with comprehensive properties. A rational thermo-foaming program is designed based on in situ observation of pore formation during heating. The fabricated PIFs have uniform pore structure, and PIFBTDA-PDA shows the smallest size (147 µm) and narrow distribution. Interestingly, PIFBTDA-PDA also presents a balanced strain recovery rate (SR = 91%) and mechanical robustness (0.051 MPa at 25% strain) and its pore structure maintains regularity after 10 compression-recovery cycles, mainly due to high rigidity of the chains. Furthermore, all the PIFs possess lightweight feature (15-20 kg∙m-3), good heat resistance (Tg at 270-340 °C), thermal stability (T5% at 480-530 °C), thermal insulation properties (λ = 0.046-0.053 W∙m-1K-1 at 20 °C, λ = 0.078-0.089 W∙m-1K-1 at 200 °C), and excellent flame retardancy (LOI > 40%). The reported monomer-mediated pore-structure control strategy can provide guidelines for the preparation of high-performance PIF and its industrial applications.