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1.
Sensors (Basel) ; 24(14)2024 Jul 13.
Article in English | MEDLINE | ID: mdl-39065938

ABSTRACT

In recent years, there has been extensive research and application of unsupervised monocular depth estimation methods for intelligent vehicles. However, a major limitation of most existing approaches is their inability to predict absolute depth values in physical units, as they generally suffer from the scale problem. Furthermore, most research efforts have focused on ground vehicles, neglecting the potential application of these methods to unmanned aerial vehicles (UAVs). To address these gaps, this paper proposes a novel absolute depth estimation method specifically designed for flight scenes using a monocular vision sensor, in which a geometry-based scale recovery algorithm serves as a post-processing stage of relative depth estimation results with scale consistency. By exploiting the feature correspondence between successive images and using the pose data provided by equipped navigation sensors, the scale factor between relative and absolute scales is calculated according to a multi-view geometry model, and then absolute depth maps are generated by pixel-wise multiplication of relative depth maps with the scale factor. As a result, the unsupervised monocular depth estimation technology is extended from relative depth estimation in semi-structured scenes to absolute depth estimation in unstructured scenes. Experiments on the publicly available Mid-Air dataset and customized data demonstrate the effectiveness of our method in different cases and settings, as well as its robustness to navigation sensor noise. The proposed method only requires UAVs to be equipped with monocular camera and common navigation sensors, and the obtained absolute depth information can be directly used for downstream tasks, which is significant for this kind of vehicle that has rarely been explored in previous depth estimation studies.

2.
J Thorac Cardiovasc Surg ; 167(1): 28-38.e8, 2024 01.
Article in English | MEDLINE | ID: mdl-35249759

ABSTRACT

OBJECTIVES: Distal stent graft-induced new entry (dSINE) can occur after thoracic endovascular aortic repair (TEVAR) for type B aortic dissection (TBAD). In this study we aimed to compare the effectiveness of restrictive bare stent (RBS), tapered stent graft (TSG), and non-TSG in TEVAR in preventing dSINE after a midterm follow-up. METHODS: This retrospective cohort study included patients with TBAD who underwent TEVAR (June 2010 to December 2018). The occurrence of dSINE during follow-up was examined. Predictors of dSINE were determined using Fine-Gray regression with death as the competing event. Survival was evaluated using Cox proportional hazards regression. RESULTS: Finally, 364 patients were included: 111 with non-TSG TEVAR, 125 with TSG TEVAR, and 128 with TEVAR with RBS. After 54.5 months, incidences of dSINE in the 3 groups were 12.61%, 4.80%, and 1.56%, respectively (P = .002). On Fine-Gray regression adjusted for clinically relevant covariates, the expansion mismatch ratio (subdistribution hazard ratio, 1.09; 95% CI, 1.07-1.12; P < .001) and complete false lumen thrombosis (subdistribution hazard ratio, 0.35; 95% CI, 0.13-0.94; P = .037) were identified as predictors of dSINE. The Cox proportional hazards regression analysis revealed that dSINE was not only a risk factor for aortic-related mortality (hazard ratio, 17.90; 95% CI, 3.27-98.12; P = .001), but also a predominant risk factor for all-cause mortality (hazard ratio, 4.91; 95% CI, 1.66-14.52; P = .004). CONCLUSIONS: dSINE can happen in TBAD patients who undergo TEVAR. Thus, long-term surveillance is crucial. TSG and RBS had lower expansion mismatch ratios, which might help prevent dSINE.


Subject(s)
Aortic Aneurysm, Thoracic , Aortic Dissection , Blood Vessel Prosthesis Implantation , Endovascular Procedures , Humans , Blood Vessel Prosthesis Implantation/adverse effects , Retrospective Studies , Aortic Aneurysm, Thoracic/diagnostic imaging , Aortic Aneurysm, Thoracic/surgery , Aortic Aneurysm, Thoracic/complications , Treatment Outcome , Endovascular Procedures/adverse effects , Postoperative Complications/etiology , Stents/adverse effects , Aortic Dissection/diagnostic imaging , Aortic Dissection/surgery , Risk Factors , Blood Vessel Prosthesis/adverse effects
3.
Article in English | MEDLINE | ID: mdl-38147284

ABSTRACT

Intrahepatic gas (IHG) is commonly observed during early postmortem examinations of humans with upper or lower airway obstructions. We conducted a study to test the hypothesis that intrapulmonary gas could retrogradely spread to the hepatic vein following pulmonary barotrauma (PB). To establish a rat model of pulmonary barotrauma, we utilized a controllable pressure-vacuum pump to apply airway pressure (40, 60, or 80 mmHg). The rats were dissected directly at the end of the experiment, and histological analysis was performed through microscopic examination of the rats. Additionally, the rats were ventilated with meglumine diatrizoate under pressures of 160 and 250 mmHg to observe the signal dynamic diffusion using X-ray fluoroscopy examination. Rats exhibited classical changes associated with PB, such as alveolar rupture, pulmonary interstitial emphysema, and hemorrhage, as well as IHG characterized by the presence of gas in the hepatic vein and hepatic sinusoids. Air emboli were not observed in the liver in any of the 40 mmHg groups. However, they were observed in the liver in the 60 and 80 mmHg groups, the amount and size of air emboli in the 80 mmHg group were greater than those in the 60 mmHg group (p < 0.05). The 80 mmHg group presented radial grape-like bubbles in the centrilobular portion of the liver accompanied by congestion in the peripheral region of the hepatic lobule. X-ray fluoroscopy examination revealed a gradual enhancement of dynamic contrast medium signals from the lung to the inferior vena cava and then to the liver. Our findings indicate that pulmonary barotrauma can lead to the retrograde spread of intrapulmonary gas to the hepatic vein. When it is clear that no decomposition of the body has occurred, the presence of IHG serves as a novel indicator for the diagnosis of obstructive pulmonary disease or obstruction in the upper or lower airway.

4.
J Hazard Mater ; 457: 131788, 2023 09 05.
Article in English | MEDLINE | ID: mdl-37302192

ABSTRACT

Organothiophosphate pesticides (OPPs) are the most common water contaminants, significantly endangering human health and bringing serious public safety issues. Thus, developing effective technologies for the removal or trace detection of OPPs from water is urgent. Herein, a novel graphene-based silica-coated core-shell tubular magnetic nanocomposite (Ni@SiO2-G) was fabricated for the first time and used for the efficient magnetic solid-phase extraction (MSPE) of the OPPs chlorpyrifos, diazinon, and fenitrothion from environmental water. The experimental factors affecting extraction efficiency such as adsorbent dosage, extraction time, desorption solvent, desorption mode, desorption time, and adsorbent type were evaluated. The synthesized Ni@SiO2-G nanocomposites showed a higher preconcentration capacity than the Ni nanotubes, Ni@SiO2 nanotubes, and graphene. Under the optimized conditions, 5 mg of tubular nano-adsorbent displayed good linearity within the range of 0.1-1 µg·mL-1, low limits of detection (0.04-0.25 pg·mL-1), low limits of quantification (0.132-0.834 pg·mL-1), good reusability (n = 5; relative standard deviations between 1.46% and 9.65%), low dosage (5 mg), and low real detection concentration (< 3.0 ng·mL-1). Moreover, the possible interaction mechanism was investigated by density functional theory calculation. Results showed that Ni@SiO2-G was a potential magnetic material for the preconcentration and extraction of formed OPPs at ultra-trace levels from environmental water.


Subject(s)
Graphite , Nanocomposites , Pesticides , Humans , Pesticides/analysis , Water , Silicon Dioxide , Nickel , Limit of Detection , Diazinon , Magnetic Phenomena , Solid Phase Extraction/methods
5.
J Colloid Interface Sci ; 638: 461-474, 2023 May 15.
Article in English | MEDLINE | ID: mdl-36758258

ABSTRACT

Fluorine-containing waste is one kind of hazardous waste characteristic by hard disposal and utilization, it is an attractive way to prepare for fluoride-based luminescent matrix. In this work, to realize the high value-added utilization of fluorine-containing waste and reduce cost of the raw materials for preparation near-infrared (NIR) glass-ceramic (GC) photocatalyst, the pure fluoride of luminescent matrix was replaced by introducing fluorine-containing waste. The waste contained NIR GC photocatalyst was synthesis by the method of facile in-situ etching of an upconversion GC with HCl, which possesses core-shell structure, where the GC micro-powder including optically active centers lanthanides doped CaF2 nanocrystals are displayed as the core, and the BiOCl is as the superficial coating. The upconversion emission performance of CaF2 based luminescent matrix in photocatalyst is not weakened with HCl etching. NIR GC photocatalyst has high methyl orange and enrofloxacin degradation rate of 86 % and 82 % over 180 min after NIR light irradiation, respectively. The UV-Vis-NIR photocatalytic activity was enhanced degradation rate (93 % in 15 min) of enrofloxacin compared with those of commercial P25 and BiOCl. In addition, the photocatalyst had stable photocatalytic activity and it also can be regenerated. The study provided references for high value-added utilization fluorine-containing waste.

6.
Materials (Basel) ; 16(2)2023 Jan 10.
Article in English | MEDLINE | ID: mdl-36676416

ABSTRACT

Carbon fiber (CF) composites performance enhancement is a research hotspot at present. In this work, first, a sandwich structure composite, CF@(carbon nanotube/Fe3O4)/epoxy (CF@(CNT/Fe3O4)/EP), is prepared by the free arc dispersion-CFs surface spraying-rolling process method, herein, CFs in the middle layer and (CNT/Fe3O4)/EP as top and substrate layer. Then, CF@(CNT/Fe3O4)/EP (on both sides) and CFs (in the middle) are overlapped by structure design, forming a multilayer CF@(CNT/Fe3O4)/EP-CFs composite with a CFs core sheath. A small amount of CNT/Fe3O4 is consumed, (CNT/Fe3O4)/EP and CFs core sheath realize thermal and electrical anisotropy and directional enhancement, and multilayer sandwich structure makes the electromagnetic interference (EMI) shielding performance better strengthened by multiple absorption-reflection/penetration-reabsorption. From CF-0 to CF-8, CNT/Fe3O4 content only increases by 0.045 wt%, axial thermal conductivity (λ‖) increases from 0.59 W/(m·K) to 1.1 W/(m·K), growth rate is 86%, radial thermal conductivity (λ⟂) only increases by 0.05 W/(m·K), the maximum λ‖/λ⟂ is 2.9, axial electrical conductivity (σ‖) increases from 6.2 S/cm to 7.7 S/cm, growth rate is 24%, radial electrical conductivity (σ⟂) only increases by 0.7 × 10-4 S/cm, the total EMI shielding effectiveness (EMI SET) increases by 196%, from 10.3 dB to 30.5 dB. This provides a new idea for enhancing CFs composite properties.

7.
ACS Appl Mater Interfaces ; 14(47): 53380-53389, 2022 Nov 30.
Article in English | MEDLINE | ID: mdl-36380466

ABSTRACT

As the world is faced with the coronavirus disease 2019 (COVID-19) pandemic, photocatalytic antibacterial ceramics can reduce the consumption of disinfectants and improve the safety of the public health environment. However, these antibacterial ceramics are often limited by poor stability and low light utilization efficiency. Herein, an antibacterial ceramic was developed via the method of facile in situ etching of upconversion glass-ceramics (UGC) (FIEG) with HCl, in which the BiOCl nanosheets were in situ grown on the surface of GC to improve its stability and antibacterial activity. The results suggest that the upconversion antibacterial ceramics can harvest and utilize near-infrared (NIR) photons efficiently, which display notable antibacterial activity for Escherichia coli (E. coli) under NIR (≥780 nm) and visible light (420-780 nm) irradiation, with a maximum inactivation rate of 7.5 log in 30 min. Meanwhile, in the cycle experiment, more than 6 log inactivation of E. coli was achieved using an antibacterial ceramic sheet after 2-h NIR light irradiation, and the stability of the antibacterial ceramic was discussed. Furthermore, the reactive species, fluorescence-based live/dead cells, and cell structure of bacteria were analyzed to verify the antibacterial mechanism. This study provides a promising strategy for the construction of efficient and stable antibacterial ceramics.


Subject(s)
COVID-19 , Escherichia coli , Humans , Ceramics/pharmacology , Anti-Bacterial Agents/pharmacology , Anti-Bacterial Agents/chemistry
8.
Oncol Rep ; 48(5)2022 11.
Article in English | MEDLINE | ID: mdl-36169181

ABSTRACT

Gomisin A (GA) is an effective component of Schisandra. The crude extracts of Schisandra chinensis and its active ingredients have been shown to inhibit multidrug resistance in tumour cells. Reactive oxygen species (ROS) have different roles in cancer and may contribute to therapy resistance. The human ovarian cancer (OC) cell lines SKOV3 and A2780, and a mouse model of OC, were used in the present study. MTT assay, colony formation assay, flow cytometry, western blot analysis, and haematoxylin and eosin (H&E) staining were performed to determine the antitumor effect of GA and paclitaxel (PTX) in vitro and in vivo. The ROS inhibitor N­acetyl cysteine (NAC) was used to assess the mechanism underlying the chemosensitizing effects of GA. Notably, the proliferation of OC cells was inhibited by PTX, which could be enhanced by the ROS inhibitor NAC or GA. Treatment with NAC + PTX or GA + PTX enhanced the cell cycle arrest, but not apoptosis, induced by PTX. Moreover, the molecular mechanism underlying this effect may be that GA decreases the levels of ROS in ovarian cancer cells and inhibits cell cycle progression by downregulating the expression of the cell cycle proteins cyclin­dependent kinase 4 and cyclin B1. In conclusion, the combination of PTX and the ROS inhibitor GA may be a novel strategy in OC chemotherapy.


Subject(s)
Ovarian Neoplasms , Paclitaxel , Animals , Carcinoma, Ovarian Epithelial , Cell Line, Tumor , Cell Proliferation , Complex Mixtures/pharmacology , Cyclin B1/metabolism , Cyclin-Dependent Kinase 4/metabolism , Cyclooctanes , Cysteine/pharmacology , Dioxoles , Eosine Yellowish-(YS)/pharmacology , Eosine Yellowish-(YS)/therapeutic use , Female , Humans , Lignans , Mice , Ovarian Neoplasms/pathology , Oxidative Stress , Paclitaxel/pharmacology , Paclitaxel/therapeutic use , Reactive Oxygen Species/metabolism
9.
Langmuir ; 38(30): 9310-9320, 2022 Aug 02.
Article in English | MEDLINE | ID: mdl-35861595

ABSTRACT

It is of significant implication to fabricate high-performance, durable and low-cost catalysts toward to oxygen reduction reaction (ORR) to drive commercial application of fuel cells. In our work, we synthesize the Fe/N-CNT catalyst via one-pot grinding combined with calcination using a mixture of carbamide, CNTs and iron salts as precursors, the as-synthesized catalysts show the structure that Fe nanoparticles are encapsulated in the tube of intertwined CNTs with abundant active sites. The catalyst is synthesized at 800 °C (Fe/N-CNT-800-20) obtain high graphitization degree and high N doped content, especially the high content and proportion of Fe-N and pyridinic-N, exhibiting outstanding ORR activity. Moreover, too high calcination temperature (850 °C) and high Fe content (25%) lead to the agglomeration of Fe during the calcination, which blocked some catalytic sites, leading to poor ORR activity. This facile synergy route will provide new thoughts for the fabrication and optimization of catalysts.

10.
Proc Natl Acad Sci U S A ; 119(30): e2202682119, 2022 07 26.
Article in English | MEDLINE | ID: mdl-35858430

ABSTRACT

Heterogeneous peroxymonosulfate (PMS)-based advanced oxidation processes (AOPs) have shown a great potential for pollutant degradation, but their feasibility for large-scale water treatment application has not been demonstrated. Herein, we develop a facile coprecipitation method for the scalable production (∼10 kg) of the Cu-Fe-Mn spinel oxide (CuFeMnO). Such a catalyst has rich oxygen vacancies and symmetry-breaking sites, which endorse it with a superior PMS-catalytic capacity. We find that the working reactive species and their contributions are highly dependent on the properties of target organic pollutants. For the organics with electron-donating group (e.g., -OH), high-valent metal species are mainly responsible for the pollutant degradation, whereas for the organics with electron-withdrawing group (e.g., -COOH and -NO2), hydroxyl radical (•OH) as the secondary oxidant also plays an important role. We demonstrate that the CuFeMnO-PMS system is able to achieve efficient and stable removal of the pollutants in the secondary effluent from a municipal wastewater plant at both bench and pilot scales. Moreover, we explore the application prospect of this PMS-based AOP process for large-scale wastewater treatment. This work describes an opportunity to scalably prepare robust spinel oxide catalysts for water purification and is beneficial to the practical applications of the heterogeneous PMS-AOPs.


Subject(s)
Aluminum Oxide , Magnesium Oxide , Peroxides , Water Pollutants , Water Purification , Aluminum Oxide/chemistry , Catalysis , Magnesium Oxide/chemistry , Peroxides/chemistry , Water Pollutants/chemistry , Water Purification/methods
11.
Nanomaterials (Basel) ; 12(7)2022 Mar 25.
Article in English | MEDLINE | ID: mdl-35407200

ABSTRACT

Biosensors have potentially revolutionized the biomedical field. Their portability, cost-effectiveness, and ease of operation have made the market for these biosensors to grow rapidly. Diabetes mellitus is the condition of having high glucose content in the body, and it has become one of the very common conditions that is leading to deaths worldwide. Although it still has no cure or prevention, if monitored and treated with appropriate medication, the complications can be hindered and mitigated. Glucose content in the body can be detected using various biological fluids, namely blood, sweat, urine, interstitial fluids, tears, breath, and saliva. In the past decade, there has been an influx of potential biosensor technologies for continuous glucose level estimation. This literature review provides a comprehensive update on the recent advances in the field of biofluid-based sensors for glucose level detection in terms of methods, methodology and materials used.

12.
Nanomaterials (Basel) ; 11(11)2021 Nov 21.
Article in English | MEDLINE | ID: mdl-34835902

ABSTRACT

Tin dioxide (SnO2)-based materials, as anode materials for lithium-ion batteries (LIBs), have been attracting growing research attention due to the high theoretical specific capacity. However, the complex synthesis process of chemical methods and the pollution of chemical reagents limit its commercialization. The new material synthesis method is of great significance for expanding the application of SnO2-based materials. In this study, the SnO2/carbon nanotube nanonests (SnO2/CNT NNs) composites are synthesized in one step by direct current (DC) arc-discharge plasma; compared with conventional methods, the plasma synthesis achieves a uniform load of SnO2 nanoparticles on the surfaces of CNTs while constructing the CNTs conductive network. The SnO2/CNT NNs composites are applied in LIBs, it can be found that the nanonest-like CNT conductive structure provides adequate room for the volume expansion and also helps to transfer the electrons. Electrochemical measurements suggests that the SnO2/CNT NNscomposites achieve high capacity, and still have high electrochemical stability and coulombic efficiency under high current density, which proves the reliability of the synthesis method. This method is expected to be industrialized and also provides new ideas for the preparation of other nanocomposites.

13.
Polymers (Basel) ; 13(21)2021 Oct 29.
Article in English | MEDLINE | ID: mdl-34771302

ABSTRACT

Electrospun nanofibers have been exploited in multidisciplinary fields with numerous applications for decades. Owing to their interconnected ultrafine fibrous structure, high surface-to-volume ratio, tortuosity, permeability, and miniaturization ability along with the benefits of their lightweight, porous nanofibrous structure, they have been extensively utilized in various research fields for decades. Electrospun nanofiber technologies have paved unprecedented advancements with new innovations and discoveries in several fields of application including energy devices and biomedical and environmental appliances. This review article focused on providing a comprehensive overview related to the recent advancements in health care and energy devices while emphasizing on the importance and uniqueness of utilizing nanofibers. A brief description regarding the effect of electrospinning techniques, setup modifications, and parameters optimization on the nanofiber morphology was also provided. The article is concluded with a short discussion on current research challenges and future perspectives.

14.
Molecules ; 26(20)2021 Oct 14.
Article in English | MEDLINE | ID: mdl-34684791

ABSTRACT

A supramolecular network [H4bdcbpy(NO3)2·H2O] (H4bdcbpy = 1,1'-Bis(3,5-dicarboxybenzyl)-4,4'-bipyridinium) (1) was prepared by a zwitterionic viologen carboxylate ligand in hydrothermal synthesis conditions. The as-synthesized (1) has been well characterized by means of single-crystal/powder X-ray diffraction, elemental analysis, thermogravimetric analysis and infrared and UV-vis spectroscopy. This compound possesses a three-dimensional supramolecular structure, formed by the hydrogen bond and π-π interaction between the organic ligands. This compound shows photochromic properties under UV light, as well as vapochromic behavior upon exposure to volatile amines and ammonia, in which the electron transfer from electron-rich parts to the electron-deficient viologen unit gives rise to colored radicals. Moreover, the intensive intermolecular H-bonding networks in 1 endows it with a proton conductivity of 1.06 × 10-3 S cm-1 in water at 90 °C.

15.
Environ Manage ; 67(4): 779-792, 2021 04.
Article in English | MEDLINE | ID: mdl-33606066

ABSTRACT

Probabilistic health risk assessment has widely been used for more realistic risk analysis of contaminants. However, the existing probabilistic modeling process may be unable to reflect the actual health risks comprehensively. In the present study, the Monte Carlo simulation was employed to assess the probabilistic health risks of exposing to arsenic (As) and cadmium (Cd) in groundwater through ingestion and dermal contact pathways. To systematically evaluate the actual health risks of residents, two scenarios of the probabilistic health risk assessment were proposed: (1) fixed exposure parameters, whereas uncertain metal concentrations, and (2) uncertain exposure parameters and metal concentrations. The results indicated that the mean hazard index (HI) for local residents was mostly accepted (HI < 1), while the non-cancer risk of infants at the 95th percentile under scenario 2 (HI = 1.42) exceeded the safe level of 1, signifying the potential non-cancer risk on infants. Meanwhile, the average total cancer risk (TCR) values were several times greater than the acceptable limit of 1E-06 for all the age groups under both scenarios 1 and 2, reflecting the unacceptable cancer risk. Moreover, sensitivity analysis identified the exposure duration (ED) and concentration factor (CW) were the most relevant parameters that affect the health risk. Overall, the results of this study will be useful for the policy makers in comprehensively understanding the actual health risks of the heavy metal(loids) contamination in groundwater on receptors, as well as setting up suitable groundwater management strategies to guarantee safe water supply and to maintain health for local residents.


Subject(s)
Arsenic , Groundwater , Metals, Heavy , Water Pollutants, Chemical , Arsenic/analysis , Arsenic/toxicity , Cadmium/toxicity , Environmental Monitoring , Humans , Metals, Heavy/analysis , Risk Assessment , Water Pollutants, Chemical/analysis , Water Pollutants, Chemical/toxicity
16.
J Clin Lab Anal ; 34(7): e23292, 2020 Jul.
Article in English | MEDLINE | ID: mdl-32157748

ABSTRACT

BACKGROUND: CircRNA plays an important role in the development of tumors, but its mechanism of action in ovarian cancer is still unclear. METHODS: The expression level of hsa_circ_0013958 in 45 pairs of ovarian cancer tissues and cells was quantified by qRT-PCR, further revealing whether it is related to clinicopathological features and diagnostic value. Next, the effects of hsa_circ_0013958 on the proliferation, migration, invasion, and apoptosis of A2780 and OVCAR-3 cells were detected by CCK-8 assay, Transwell assay, and flow cytometry, respectively. Last, the expression levels of epithelial-mesenchymal transition-related proteins (E-cadherin and Vimentin) and apoptosis-related proteins (Bcl-2 and Bax) were detected by Western blotting. RESULTS: Hsa_circ_0013958 was highly expressed in ovarian cancer tissues and cells, and its expression was closely related to patient FIGO stage and lymph node metastasis. Further, in vitro studies showed that knockdown of hsa_circ_0013958 suppressed proliferation, migration, and invasion of ovarian cancer cells but elevated the cell apoptotic rate. The expression levels of both epithelial-mesenchymal transition-related proteins and apoptosis-related proteins were also changed. CONCLUSIONS: Hsa_circ_0013958 may contribute to the development of ovarian cancer by affecting epithelial-mesenchymal transition and apoptotic signaling pathways.


Subject(s)
Apoptosis/genetics , Epithelial-Mesenchymal Transition/genetics , Ovarian Neoplasms/pathology , RNA, Circular/genetics , Apoptosis/physiology , Biomarkers, Tumor/genetics , Case-Control Studies , Cell Line, Tumor , Cell Movement/genetics , Cell Proliferation/genetics , Down-Regulation/genetics , Female , Gene Expression Regulation, Neoplastic , Humans , Middle Aged , Ovarian Neoplasms/genetics , ROC Curve
17.
J Phys Chem Lett ; 11(9): 3350-3356, 2020 May 07.
Article in English | MEDLINE | ID: mdl-32191486

ABSTRACT

Defects within zeolites are crucially important for explaining their physicochemical behavior. The UTL zeolite, with a pillared layer structure, has been widely used in zeolite crystal engineering to assemble new structures from its layered structural units, but a fundamental understanding of its defect is lacking. Here, we report a newly synthesized UTL framework zeolite, UTL-DBU, with a commercially available superbase 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) as a template. Its structure was determined by a combination of three-dimensional electron diffraction tomography and high-resolution (scanning) transmission electron microscopy. Using transmission electron microscopy, two types of defects, stacking disorder and edge dislocation-like planar defect, were discovered. On the basis of the analysis of the electron diffraction and imaging, the layer stacking sequence together with the structural and mathematical models of the microtwinning was successfully built up. Unraveling these defects will provide new insights into the rational design of targeted zeolites utilizing UTL.

18.
Chem Sci ; 11(44): 12103-12108, 2020 Oct 20.
Article in English | MEDLINE | ID: mdl-34123221

ABSTRACT

Aluminosilicate boggsite (Si/Al-BOG) has been hydrothermally synthesized without adding organic structure-directing agents (OSDAs) in the synthesis gel using the borosilicogermanium ITQ-47 (Si/B-ITQ-47) zeolite as seeds. The introduction of the costly and environmentally less benign phosphazene organic structure-directing agent is not required to grow the zeolite. Physicochemical characterization experiments show that Si/Al-BOG has good crystallinity, high surface area, tetrahedral Al3+ species, and acid sites. In order to test the catalytic performance of the zeolite, the synthesis of l,l-lactide from l-lactic acid was performed. Si/Al-BOG exhibits 88.2% conversion of l-lactic acid and 83.8% l,l-lactide selectivity, which are better than those of other zeolites studied up to now.

20.
Chem Sci ; 10(32): 7600-7609, 2019 Aug 28.
Article in English | MEDLINE | ID: mdl-31588311

ABSTRACT

The key challenges of aqueous Zn-based batteries (ZBBs) are their unsatisfactory energy density and poor lifespan, mainly arising from the low capacity and irreversibility of the cathode materials. Herein, a three-dimensional (3D) ordered mesoporous nanoarchitecture cobaltosic oxide (M-Co3O4) with rich oxygen vacancies (M-Co3O4-x ) is reported as a new promising advanced cathode material for rechargeable ZBBs. The experimental results and DFT calculations reveal that the energy storage capacity is significantly enhanced by the synergistic effect of mesopores and oxygen vacancies. Benefiting from the merits of a substantially fast ion diffusion channel, high electrical conductivity, large active surface area, strong OH- adsorption capacity and stable structure, the fabricated M-Co3O4-x //Zn battery delivers a remarkable capacity of 384 mA h g-1 at 1.0 A g-1 which even rises up to 420 mA h g-1 after cycling activation with an ultrahigh energy density of 722.4 W h kg-1 (based on the weights of the cathode active material), which outperforms most of the previously reported aqueous ZBBs. More impressively, the M-Co3O4-x //Zn battery exhibits extraordinary cycling stability, both at 1 A g-1 and 10 A g-1 without any decay of capacity after 6000 and 60 000 cycles, respectively, and such high cycling stability is reported for the first time in ZBBs. The ultrahigh energy and superlong lifespan of aqueous ZBBs could make it satisfy some practical energy demands.

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