Triple Synergism Effect of Ammonium Nitrilotriacetate on the Chemical Mechanical Polishing Performance of Ruthenium Barrier Layers.

As the feature size of integrated circuits continues to decrease, ruthenium (Ru) has been suggested as the successor to traditional Ta/TaN bilayers for barrier layer materials due to its unique properties. This research delves into the effects of ammonium nitrilotriacetate (NTA(NH4 )3 ) on the chemical mechanical polishing (CMP) performance of Ru in H2 O2 -based slurry. The removal rate (RR) of Ru surged from 47 to 890 Å min-1 , marking an increase of about 17 times. The essence of this mechanism lies in the triple synergistic effects of NTA(NH4 )3 in promoting ruthenium (Ru) removal: 1) The interaction between NH 4 + ${\mathrm{NH}}_{\mathrm{4}}^{\mathrm{+}}$ from NTA(NH4 )3 and SiO2 abrasives; 2) The chelating action of [(NH4 )N(CH2 COO)3 ]2-  from NTA(NH4 )3 on Ru and its oxides; 3) The ammoniation and chelation of Ru and its oxides by NH 4 + ${\mathrm{NH}}_{\mathrm{4}}^{\mathrm{+}}$ from NTA(NH4 )3 , which enhance the dissolution and corrosion of oxidized Ru, making its removal during the barrier layer CMP process more efficient through mechanical means. This research introduces a synergistic approach for the effective removal of Ru, shedding light on potential applications of CMP in the field of the integrated circuits.

PtPd NPs-functionalized metal-organic framework-derived α-Fe2O3 porous spindles for efficient low-temperature detection of triethylamine.

In recent years, metal-organic framework (MOF) derivatives have gradually become ideal materials for gas sensors due to their controllable composition, diverse structures and open metal sites. In this research, a simplified hydrothermal method was applied to successfully prepare MOF-derived α-Fe2O3 spindles, and an in situ reduction method was then utilized to deposit Pt, Pd and PtPd bimetallic nanoparticles (NPs) on the α-Fe2O3 spindles. The effects of noble metals Pt, Pd and PtPd on the gas-sensing properties of Fe2O3 were systematically examined. The PtPd/α-Fe2O3 sensor has enhanced gas-sensing performance for triethylamine (TEA), especially at PtPd content of 1.5 wt% and mass ratio of Pt : Pd = 90 : 10, where the response of the sensor to 100 ppm TEA at a lower temperature of 150 °C is 442, which is 34 times higher than that of the original α-Fe2O3 (response of 13). Additionally, the sensor demonstrated improved response/recovery properties and very respectable selectivity, repeatability, long-term stability within 30 days and lower detection limit (500 ppb) at 150 °C. Combining the results of XPS and O2-TPD, the enhanced gas-sensing properties of PtPd bimetallic-modified α-Fe2O3 over monometallic (Pt or Pd) modified α-Fe2O3 were analyzed, which can be attributed to the chemical and electronic sensitization of noble metals and the synergistic effect of the PtPd bimetallic NPs, resulting in more surface defects and enhanced oxygen adsorption capacity of the sensing material. This work provided an effective gas-sensing material for the low-temperature detection and analysis of triethylamine gas.

High-Performance N-Butanol Gas Sensor Based on Iron-Doped Metal-Organic Framework-Derived Nickel Oxide and DFT Study.

In this study, a straightforward two-step hydrothermal process was used to synthesize Fe-doped NiO nanomaterials. A number of characterization approaches were employed to explore the structure and morphology of the synthesized Fe-doped NiO. The as-prepared samples were multi-layered flower-like structures formed by nanoparticles, according to scanning electron microscopy and transmission electron microscopy studies. The findings of the study on gas sensing performance showed that the response of the 1.5 at % Fe-NiO sensor was nearly 100 times greater than that of the pure NiO sensor, and the lower limit of detection was greatly decreased (50 ppb). The 1.5 at % Fe-NiO sensor exhibited superior sensing performance for n-butanol. The incorporation of an appropriate amount of Fe into the NiO lattice modified the carrier concentration, which is the primary cause of the increased sensor performance of an appropriate amount of Fe-doped NiO. In addition, the density functional theory calculation method based on the first-principles theory was used to study the adsorption performance and electronic behavior of pure NiO and 1.5 at % Fe-NiO for n-butanol. The calculated results were consistent with the experimental results.

Nanoscale Surface Refinement of CoCrMo Alloy for Artificial Knee Joints via Chemical Mechanical Polishing.

In this study, we address the challenge of surface roughness in CoCrMo alloys, typically used in artificial knee joints, which can initiate a cascade of biological responses causing inflammation, osteolysis, joint instability, and increased susceptibility to infection. We propose the application of a chemical mechanical polishing (CMP) technique, using an ecologically responsible slurry composed of 4 wt% SiO2, 0.3 wt% H2O2, 1.0 wt% glycine, and 0.05 wt% benzotriazole. Our innovative approach demonstrated significant improvements, achieving a material removal rate of 30.9 nm/min and reducing the arithmetic mean roughness from 20.76 nm to 0.25 nm, thereby enhancing the nanoscale surface quality of the artificial knee joint alloy. The smoother surface is attributed to a decrease in corrosion potential to 0.18 V and a reduction in corrosion current density from 9.55 µA/cm2 to 4.49 µA/cm2 with the addition of BTA, evidenced by electrochemical tests. Furthermore, the preservation of the phase structure of the CoCrMo alloy, as confirmed by XRD analysis and elemental mapping, ensures the structural integrity of the treated surfaces. These outcomes and our simulation results demonstrate the effectiveness of our CMP method in engineering surface treatments for artificial knee joints to optimize friction behavior and potentially extend their lifespans.

Subsurface oxygen defects electronically interacting with active sites on In2O3 for enhanced photothermocatalytic CO2 reduction.

Oxygen defects play an important role in many catalytic reactions. Increasing surface oxygen defects can be done through reduction treatment. However, excessive reduction blocks electron channels and deactivates the catalyst surface due to electron-trapped effects by subsurface oxygen defects. How to effectively extract electrons from subsurface oxygen defects which cannot directly interact with reactants is challenging and remains elusive. Here, we report a metallic In-embedded In2O3 nanoflake catalyst over which the turnover frequency of CO2 reduction into CO increases by a factor of 866 (7615 h-1) and 376 (2990 h-1) at the same light intensity and reaction temperature, respectively, compared to In2O3. Under electron-delocalization effect of O-In-(O)Vo-In-In structural units at the interface, the electrons in the subsurface oxygen defects are extracted and gather at surface active sites. This improves the electronic coupling with CO2 and stabilizes intermediate. The study opens up new insights for exquisite electronic manipulation of oxygen defects.

[Misdiagnosis of Acute Renal Artery Thrombosis as Acute Abdominal Disease:Report of One Case].

Renal artery thrombosis can cause acute occlusion of unilateral or bilateral renal arteries,and kidney failure would be induced if it is not diagnosed and treated in time.Therefore,rapid and correct treatment is especially important for renal artery thrombosis.Due to the lack of specificity of clinical manifestations,this disease in commonly misdiagnosed or missed and thus has a low early diagnosis rate.Here we report a case of acute renal artery thrombosis to improve the diagnosis and treatment.

COVID-19: Effects of Environmental Conditions on the Propagation of Respiratory Droplets.

As coronavirus disease 2019 (COVID-19) continues to spread, a detailed understanding on the transmission mechanisms is of paramount importance. The disease transmits mainly through respiratory droplets and aerosol. Although models for the evaporation and trajectory of respiratory droplets have been developed, how the environment impacts the transmission of COVID-19 is still unclear. In this study, we investigate the propagation of respiratory droplets and aerosol particles generated by speech under a wide range of temperatures (0-40 °C) and relative humidity (0-92%) conditions. We show that droplets can travel three times farther in low-temperature and high-humidity environment, whereas the number of aerosol particles increases in high-temperature and low-humidity environments. The results also underscore the importance of proper ventilation, as droplets and aerosol spread significantly farther in airstreams. This study contributes to the understanding of the environmental impact on COVID-19 transmission.

Photoinduced Defect Engineering: Enhanced Photothermal Catalytic Performance of 2D Black In2 O3- x Nanosheets with Bifunctional Oxygen Vacancies.

Photothermal CO2 reduction technology has attracted tremendous interest as a solution for the greenhouse effect and energy crisis, and thereby it plays a critical role in solving environmental problems and generating economic benefits. In2 O3- x has emerged as a potential photothermal catalyst for CO2 conversion into CO via the light-driven reverse water gas shift reaction. However, it is still a challenge to modulate the structural and electronic characteristics of In2 O3 to enhance photothermocatalytic activity synergistically. In this work, a novel route to activate inert In(OH)3 into 2D black In2 O3- x nanosheets via photoinduced defect engineering is proposed. Theoretical calculations and experimental results verify the existence of bifunctional oxygen vacancies in the 2D black In2 O3- x nanosheets host, which enhances light harvesting and chemical adsorption of CO2 molecules dramatically, achieving 103.21 mmol gcat -1 h-1 with near-unity selectivity for CO generation and meanwhile excellent stability. This study reveals an exciting phenomenon that light is an ideal external stimulus on the layered In2 O3 system, and its electronic structure can be adjusted efficiently through photoinduced defect engineering; it can be anticipated that this synthesis strategy can be extended to wider application fields.

Solar-Driven Water-Gas Shift Reaction over CuOx /Al2 O3 with 1.1 % of Light-to-Energy Storage.

Hydrogen production from coal gasification provides a cleaning approach to convert coal resource into chemical energy, but the key procedures of coal gasification and thermal catalytic water-gas shift (WGS) reaction in this energy technology still suffer from high energy cost. We herein propose adopting a solar-driven WGS process instead of traditional thermal catalysis, with the aim of greatly decreasing the energy consumption. Under light irradiation, the CuOx /Al2 O3 delivers excellent catalytic activity (122 µmol gcat -1 s-1 of H2 evolution and >95 % of CO conversion) which is even more efficient than noble-metal-based catalysts (Au/Al2 O3 and Pt/Al2 O3 ). Importantly, this solar-driven WGS process costs no electric/thermal power but attains 1.1 % of light-to-energy storage. The attractive performance of the solar-driven WGS reaction over CuOx /Al2 O3 can be attributed to the combined photothermocatalysis and photocatalysis.

Microfluidic hydrodynamic focusing synthesis of polymer-lipid nanoparticles for siRNA delivery.

Small interfering RNAs (siRNAs) are promising as therapeutics for intractable diseases such as cancer. However, efficient and safe delivery of siRNAs in vivo remains a challenge. Polymer-lipid hybrid nanoparticles (P/LNPs) have been evaluated for therapeutic delivery of siRNA. In this study, a microfluidic hydrodynamic focusing (MF) system was used to prepare P/LNPs loaded with VEGF siRNA. P/LNPs made by MF were smaller in particle size and had narrower size distribution compared to P/LNPs formed by bulk mixing (BM). MF-synthesized P/LNPs demonstrated low vehicle cytotoxicity and potent tumor cell inhibition in vitro. In addition, P/LNPs produced by the microfluidic chip exhibited prolonged blood circulation and increased AUC after i.v. injection compared to free siRNA. Furthermore, P/LNPs synthesized by MF induced greater down-regulation of VEGF mRNA and protein levels as well as greater tumor inhibition in a xenograft tumor model. Taken together, P/LNPs prepared by MF have been shown to be an effective and safe therapeutic siRNA delivery system for cancer treatment both in vitro and in vivo.

CO2 -Assisted Fabrication of Two-Dimensional Amorphous Molybdenum Oxide Nanosheets for Enhanced Plasmon Resonances.

As a remarkable class of plasmonic materials, two dimensional (2D) semiconductor compounds have attracted attention owing to their controlled manipulation of plasmon resonances in the visible light spectrum, which outperforms conventional noble metals. However, tuning of plasmonic resonances for 2D semiconductors remains challenging. Herein, we design a novel method to obtain amorphous molybdenum oxide (MoO3 ) nanosheets, in which it combines the oxidation of MoS2 and subsequent supercritical CO2 -treatment, which is a crucial step for the achievement of amorphous structure of MoO3 . Upon illumination, hydrogen-doped MoO3 exhibits tuned surface plasmon resonances in the visible and near-IR regions. Moreover, a unique behavior of the amorphous MoO3 nanosheets has been found in an optical biosensing system; there is an optimum plasmon resonance after incubation with different BSA concentrations, suggesting a tunable plasmonic device in the near future.

Single-step microfluidic synthesis of transferrin-conjugated lipid nanoparticles for siRNA delivery.

Microfluidic systems can accelerate clinical translation of nanoparticles due to their ability to generate nanoparticles in a well-controlled and reproducible manner. In this study, a single-step process based on microfluidic focusing (MF) was employed to synthesize transferrin-conjugated lipid nanoparticles (Tf-LNPs) and the method was compared with a multi-steps bulk mixing (BM) method. The results indicate that this single-step MF process enables rapid and efficient synthesis of Tf-LNPs, which were named Tf-LNPs-MF. Tf-LNPs-MF was shown to have a smaller size and more uniform structures compared to LNPs produced by multi-steps BM method (Tf-LNPs-BM). Furthermore, efficient cellular uptake of Tf-LNPs-MF in vitro as well as greater tumor inhibition in vivo proved that Tf-LNPs-MF had higher siRNA delivery efficiency in vitro and in vivo. Taken together, this single-step microfluidic synthesis significantly simplified the Tf-LNPs production and improved their drug delivery properties and may serve as a valuable tool for developing new cancer therapies.

Synthesis of Polymer-Lipid Nanoparticles by Microfluidic Focusing for siRNA Delivery.

Polyethylenimine (PEI) as a cationic polymer is commonly used as a carrier for gene delivery. PEI-800 is less toxic than PEI-25K but it is also less efficient. A novel nanocarrier was developed by combining PEI-800 with a pH-sensitive lipid to form polymer-lipid hybrid nanoparticles (P/LNPs). They were synthesized by microfluidic focusing (MF). Two microfluidic devices were used to synthesize P/LNPs loaded with VEGF siRNA. A series of P/LNPs with different particle sizes and distributions were obtained by altering the flow rate and geometry of microfluidic chips, and introducing sonication. Furthermore, the P/LNPs can be loaded with VEGF siRNA efficiently and were stable in serum for 12 h. Finally, P/LNPs produced by the microfluidic chip showed greater cellular uptake as well as down-regulation of VEGF protein level in both A549 and MCF-7 with reduced cellular toxicity. All in all, the P/LNPs produced by MF method were shown to be a safe and efficient carrier for VEGF siRNA, with potential application for siRNA therapeutics.

Delivery of siRNA Using Lipid Nanoparticles Modified with Cell Penetrating Peptide.

Clinical development of siRNA has been hindered by the lack of an effective delivery system. Here, we report the construction of a novel siRNA delivery system, sTOLP, which is based on cell penetrating peptide oleoyl-octaarginine (OA-R8) modified multifunctional lipid nanoparticles. sTOLP nanoparticles are composed of a protamine complexed siRNA core, OA-R8, cationic and PEGylated lipids, and transferrin as a targeting ligand. sTOLP formulation was optimized and characterized in vitro and showed excellent gene silencing activity. In vivo, siRNA encapsulated in sTOLP exhibited potent tumor inhibition (61.7%) and was preferentially taken up by hepatocytes and tumor cells in HepG2-bearing nude mice without inducing immunogenicity or hepatic or renal toxicity. Furthermore, sTOLP-loaded siRNA had stability in circulation greater than that of free siRNA. These data demonstrated potential utility of sTOLP-mediated siRNA delivery in cancer therapy.

Delivery of siRNA Using Cationic Liposomes Incorporating Stearic Acid-modified Octa-Arginine.

Cationic liposomes incorporating stearic acid-modified octa-arginine (StA-R8) were evaluated for survivin small interfering RNA (siRNA) delivery. StA-R8 was synthesized and incorporated into liposomes. The composition of liposomes was optimized. Physicochemical properties, cytotoxicity, cellular uptake and gene silencing activity of the liposomes complexed to survivin siRNA were investigated. The results showed that StA-R8-containing liposomes had reduced cytotoxicity and improved delivery efficiency of siRNA into cancer cells compared with StA-R8 by itself.

CO2-Induced Phase Engineering: Protocol for Enhanced Photoelectrocatalytic Performance of 2D MoS2 Nanosheets.

Molybdenum disulfide (MoS2) is a promising non-precious-metal catalyst, but its performance is limited by the density of active sites and poor electrical transport. Its metallic 1T phase possesses higher photoelectrocatalytic activity. Thus, how to efficiently increase the concentration of the 1T phase in the exfoliated two-dimensiaonal (2D) MoS2 nanosheets is an important premise. In this work, we propose a strategy to prepare a 2D heterostructure of MoS2 nanosheets using supercritical CO2-induced phase engineering to form metallic 1T-MoS2. Theoretical calculations and experimental results demonstrate that the introduced CO2 in the 2H-MoS2 host can prompt the transformation of partial 2H-MoS2 lattices into 1T-MoS2. Moreover, the electrical coupling and synergistic effect between 2H and 1T phases can greatly facilitate the efficient electron transfer from the active sites of MoS2, which significantly improves the photocatalytic performance.

High-efficiency exfoliation of layered materials into 2D nanosheets in switchable CO2/Surfactant/H2O system.

Layered materials present attractive and important properties due to their two-dimensional (2D) structure, allowing potential applications including electronics, optoelectronics, and catalysis. However, fully exploiting the outstanding properties will require a method for their efficient exfoliation. Here we present that a series of layered materials can be successfully exfoliated into single- and few-layer nanosheets using the driving forces coming from the phase inversion, i.e., from micelles to reverse micelles in the emulsion microenvironment built by supercritical carbon dioxide (SC CO2). The effect of variable experimental parameters including CO2 pressure, ethanol/water ratio, and initial concentration of bulk materials on the exfoliation yield have been investigated. Moreover, we demonstrate that the exfoliated 2D nanosheets have their worthwhile applications, for example, graphene can be used to prepare conductive paper, MoS2 can be used as fluorescent label to perform cellular labelling, and BN can effectively reinforce polymers leading to the promising mechanical properties.

A green route to fabricate MoS2 nanosheets in water-ethanol-CO2.

We show that bulk MoS2 can be efficiently exfoliated into ultrathin nanosheets in supercritical CO2 with ethanol as cosolvent. Moreover, such tailored MoS2 nanostructures, when they are directly used as labels for bioimaging, show excellent imaging effects with strong fluorescence and nontoxicity.

Synthesis of strongly fluorescent molybdenum disulfide nanosheets for cell-targeted labeling.

MoS2 nanosheets with polydispersity of the lateral dimensions from natural mineral molybdenite have been prepared in the emulsions microenvironment built by the water/surfactant/CO2 system. The size, thickness, and atomic structure are characterized by transmission electron microscopy (TEM), atomic force microscopy (AFM), and laser-scattering particle size analysis. Meanwhile, by the analysis of photoluminescence spectroscopy and microscope, the MoS2 nanosheets with smaller lateral dimensions exhibit extraordinary photoluminescence properties different from those with relatively larger lateral dimensions. The discovery of the excitation dependent photoluminescence for MoS2 nanosheets makes them potentially of interests for the applications in optoelectronics and biology. Moreover, we demonstrate that the fabricated MoS2 nanosheets can be a nontoxic fluorescent label for cell-targeted labeling application.