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1.
Appl Environ Microbiol ; 87(11)2021 May 11.
Artigo em Inglês | MEDLINE | ID: mdl-33975896

RESUMO

Nitrification is an essential process for nutrient removal from wastewater and an important emission source of nitrous oxide (N2O), which is a powerful greenhouse gas and a dominant ozone-depleting substance. In this study, nitrification and N2O emissions were tested in two weakly acidic (pH 6.3 to 6.8) reactors: one with dissolved oxygen (DO) at over 2.0 mg/liter and the other with DO at approximately 0.5 mg/liter. Efficient nitrification was achieved in both reactors. Compared to that in the high-DO reactor, N2O emission in the low-DO reactor decreased slightly, by 20%, and had insignificant correlation with the fluctuations of DO (P = 0.935) and nitrite (P = 0.713), indicating that N2O might not be produced mainly via nitrifier denitrification. Based on quantitative PCR (qPCR), quantitative fluorescent in situ hybridization (qFISH), and functional gene amplicon and metagenome sequencing, it was found that complete ammonia oxidizers (comammox), i.e., Nitrospira organisms, significantly outnumbered canonical ammonia-oxidizing bacteria (AOB) in both weakly acidic reactors, especially in the low-DO reactor with the comammox/AOB amoA gene ratio increasing from 6.6 to 17.1. Therefore, it was speculated that the enriched comammox was the primary cause for the slightly decreased N2O emission under long-term low DO in the weakly acidic reactor. This study demonstrated that the comammox Nitrospira can survive well under the weakly acidic and low-DO conditions, implying that achieving efficient nitrification with low N2O emission as well as low energy and alkalinity consumption is feasible for wastewater treatment.IMPORTANCE Nitrification in wastewater treatment is an important process for eutrophication control and an emission source for the greenhouse gas N2O. The nitrifying process is usually operated at a slightly alkaline pH and high DO (>2 mg/liter) to ensure efficient nitrification. However, it consumes a large amount of energy and chemicals, especially for wastewater without sufficient alkalinity. This paper demonstrates that comammox can adapt well to the weakly acidic and low-DO bioreactors, with a result of efficient nitrification and low N2O emission. These findings indicate that comammox organisms are significant for sustainable wastewater treatment, which provides an opportunity to achieve efficient nitrification with low N2O production as well as low energy and chemical consumption simultaneously.

2.
Biomed Eng Online ; 20(1): 45, 2021 May 03.
Artigo em Inglês | MEDLINE | ID: mdl-33941179

RESUMO

BACKGROUND: Nonalcoholic fatty liver disease (NAFLD) is rapidly becoming one of the most common liver diseases. Ultrasound elastography has been used for the diagnosis of NAFLD. However, clinical research on steatosis by elastography technology has mainly focused on steatosis with fibrosis or non-alcoholic steatohepatitis (NASH), while steatosis without fibrosis has been poorly studied. Moreover, the relationship between liver viscoelasticity and steatosis grade is not clear. In this study, we evaluated the degree of liver steatosis in a simple steatosis rat model using shear wave elastography (SWE). RESULTS: The viscoelasticity values of 69 rats with hepatic steatosis were measured quantitatively by SWE in vivo and validated by a dynamic mechanical analysis (DMA) test. Pathological sections were used to determine the steatosis grade for each rat. The results showed that the elasticity values µ obtained by the two methods followed the same trend, and µ is significantly correlated with liver steatosis. The Pearson's correlation coefficients indicate that [Formula: see text] obtained by SWE is positively linear correlated with DMA (r = 0.628, p = 7.85 × 10-9). However, the viscosity values [Formula: see text] obtained by SWE were relatively independent of those obtained by DMA with a correlation coefficient of - 0.01. The combined Voigt elasticity measurements have high validity in the prediction of steatosis (S0 vs. S1-S4), with an AUROC of 0.755 (95% CI 0.6175-0.8925, p < 0.01) and the optimal cutoff value was 2.08 kPa with a sensitivity of 78% and specificity of 63%. CONCLUSION: SWE might have the feasibility to be introduced as an auxiliary technique for NAFLD patients in clinical settings. However, the viscosity results measured by SWE and DMA are significantly different, because the two methods work in different frequency bands.

3.
J Am Chem Soc ; 2021 Apr 30.
Artigo em Inglês | MEDLINE | ID: mdl-33929193

RESUMO

Axially, epitaxially organizing nano-objects of distinct compositions and structures into superlattice nanowires enables full utilization of sunlight, readily engineered band structures, and tunable geometric parameters to fit carrier transport, thus holding great promise for optoelectronics and solar-to-fuel conversion. To maximize their efficiency, the general and high-precision synthesis of colloidal axial superlattice nanowires (ASLNWs) with programmable compositions and structures is the prerequisite; however, it remains challenging. Here, we report an axial encoding methodology toward the ASLNW library with precise control over their compositions, dimensions, crystal phases, interfaces, and periodicity. Using a predesigned, editable nanoparticle framework that offers the synthetic selectivity, we are able to chemically decouple adjacent sub-objects in ASLNWs and thus craft them in a controlled approach, yielding a library of distinct ASLNWs. We integrate therein plasmonic, metallic, or near-infrared-active chalcogenides, which hold great potential in solar energy conversion. Such synthetic capability enables a performance boost in target applications, as we report order-of-magnitude enhanced photocatalytic hydrogen production rates using optimized ASLNWs compared to corresponding solo objects. Furthermore, it is expected that such unique superlattice nanowires could bring out new phenomena.

4.
Environ Sci Technol ; 2021 Apr 27.
Artigo em Inglês | MEDLINE | ID: mdl-33904707

RESUMO

Nitrous oxide (N2O) is an important greenhouse gas and a dominant ozone-depleting substance. Nitrification in the activated sludge process (ASP) is an important N2O emission source. This study demonstrated that a short-term low dissolved oxygen (DO) increased the N2O emissions by six times, while long-term low DO operation decreased the N2O emissions by 54% (P < 0.01). Under long-term low DO, the ammonia oxidizer abundance in the ASP increased significantly, and thus, complete nitrification was recovered and no NH3 or nitrite accumulated. Moreover, long-term low DO decreased the abundance of ammonia-oxidizing bacteria (AOB) by 28%, while increased the abundance of ammonia-oxidizing archaea (AOA) by 507%, mainly due to their higher oxygen affinity. As a result, AOA outnumbered AOB with the AOA/AOB amoA gene ratio increasing to 19.5 under long-term low DO. The efficient nitrification and decreased AOB abundance might not increase N2O production via AOB under long-term low DO conditions. The enriched AOA could decrease the N2O emissions because they were reported to lack canonical nitric oxide (NO) reductase genes that convert NO to N2O. Probably because of AOA enrichment, the positive and significant (P = 0.02) correlation of N2O emission and nitrite concentration became insignificant (P = 0.332) after 80 days of low DO operation. Therefore, ASPs can be operated with low DO and extended sludge age to synchronously reduce N2O production and carbon dioxide emissions owing to lower aeration energy without compromising the nitrification efficiency.

5.
Mar Pollut Bull ; 167: 112318, 2021 Apr 13.
Artigo em Inglês | MEDLINE | ID: mdl-33862382

RESUMO

The presence of polychlorinated biphenyls (PCBs) and dichlorodiphenyltrichloroethanes (DDTs) was determined in the sediments of Beibu Gulf, a newly developing industry and port in South China, to evaluate whether the rapid development of coastal cities has accelerated the organic pollution in the region. The levels of PCBs and DDTs ranged from 1.17 to 8.00 ng g-1 and ND (not detected) to 3.82 ng g-1, respectively. The levels were higher in the east of Beibu Gulf than in the west, which influenced by the industrialisation and urbanisation in the east. Additionally, penta-PCBs were the dominant PCB congeners, which are related to shipping activities, and DDTs may have originated from the historical use of technical DDT. The levels of pp'-DDD and PCBs did not have the potential to cause ecological risks in Beibu Gulf; however, residues of DDTs were at relatively higher ecotoxicological levels, thereby having the potential to cause adverse biological effects.

6.
Artigo em Inglês | MEDLINE | ID: mdl-33755429

RESUMO

Bismuth telluride has been the only commercial thermoelectric candidate, but the n-type sintered material lags well behind the p-type one in the zT value, which severely limits the further development of thermoelectrics. Here, we report a promising technique named hot-stacked deformation to effectively improve the thermoelectric properties of n-type Bi2Te2.79Se0.21 + 0.067 wt % BiCl3 materials based on zone-melting ingots. It is found that a high grain alignment is maintained during the plastic deformation and the carrier concentration is properly optimized owing to the donor-like effect, leading to an enhanced power factor. Moreover, the lattice thermal conductivity is obviously suppressed due to the emerged phonon scattering centers of dense grain boundaries and dislocations. These effects synergistically yield a maximum zT value of 1.38 and an average zTave of 1.18 between 300 and 500 K in the hot-stacked deformed sample, which is approximately 42% higher than those of the zone-melting ingots.

7.
J Atheroscler Thromb ; 2021 Feb 27.
Artigo em Inglês | MEDLINE | ID: mdl-33642443

RESUMO

AIMS: This study aims to evaluate the differences in the characteristics of atherosclerotic plaques in the proximal, curved, and distal segments of the curved basilar artery (BA) through high-resolution magnetic resonance imaging(HR-MRI). METHODS: The imaging and clinical data of 146 patients were retrospectively analyzed. On the basis of three-dimensional (3D) time -of -flight magnetic resonance angiography (3D-TOF-MRA), 51 patients with BA curvature were selected for the study. The BA plaque is divided into three groups: proximal, curved, and distal. Plaques were identified and analyzed according to spin echo acquisition imaging via T1-weighted 3D volumetric isotropic Tse acquisition (T1W-3D -VISTA), and compare the differences in clinical related factors and plaque characteristics between groups. Diffusion-weighted imaging (DWI) and/or T2WI identified brainstem infarction. The patients were divided into symptomatic and asymptomatic groups. The correlation between plaque location and symptoms was identified and analyzed. RESULTS: Among 51 patients, a total of 376 plaques were detected. Plaques in the proximal and curved segments are more common than those in the distal segments. Proximal plaques are more likely to have intraplaque hemorrhage (P=0.002 <0.05). There was no significant difference in the distribution of criminal plaques and non-criminal plaques between each group (P=0.36 >0.05). CONCLUSION: Plaques in the proximal and curved segments of the BA are more common than those in the distal segments. The proximal plaque is more prone to intraplaque hemorrhage.

8.
Artigo em Inglês | MEDLINE | ID: mdl-33741624

RESUMO

Nitrification is an essential process for nutrient removal from wastewater and an important emission source of nitrous-oxide (N2O), which is a powerful greenhouse gas and a dominant ozone-depleting substance. In this study, nitrification and N2O emissions were tested in two weakly acidic (pH = 6.3-6.8) reactors: one with dissolved oxygen (DO) over 2.0 mg/L and the other with DO approximately 0.5 mg/L. Efficient nitrification was achieved in both reactors. Compared to the high-DO reactor, N2O emission in the low-DO reactor decreased slightly by 20% and had insignificant correlation with the fluctuations of DO (P = 0.935) and nitrite (P = 0.713), indicating that N2O might not be mainly produced via nitrifier denitrification. Based on qPCR, qFISH, functional gene amplicon and metagenome sequencing, it was found that complete ammonia oxidizer (comammox) Nitrospira significantly outnumbered canonical ammonia-oxidizing bacteria (AOB) in both weakly acidic reactors, especially in the low DO reactor with the comammox/AOB amoA gene ratio increasing from 6.6 to 17.1. Therefore, it was speculated that the enriched comammox was the primary cause for the slightly decreased N2O emission under long-term low DO in weakly acidic reactor. This study demonstrated that comammox Nitrospira can survive well under the weakly acidic and low-DO conditions, implying that achieving efficient nitrification with low N2O emission as well as low energy and alkalinity consumption is feasible for wastewater treatment.ImportanceNitrification in wastewater treatment is an important process for eutrophication control and an emission source for greenhouse gas of N2O. The nitrifying process is usually operated at a slightly alkaline pH and high DO (>2 mg/L) to ensure efficient nitrification. However, it consumes a large amount of energy and chemicals especially for wastewater without sufficient alkalinity. This manuscript demonstrated that comammox can adapt well to the weakly acidic and low-DO bioreactors, with a result of efficient nitrification and low N2O emission. These findings indicate that comammox are significant for sustainable wastewater treatment, which provides an opportunity to achieve efficient nitrification with low N2O production as well as low energy and chemical consumption simultaneously.

9.
Sci Total Environ ; 780: 146639, 2021 Mar 21.
Artigo em Inglês | MEDLINE | ID: mdl-33773340

RESUMO

In present study, the effects of inorganic particles and their interaction with biofilms on the filtration behavior of dynamic membrane bioreactor (DMBR) were investigated. When no inorganic particles were included in the simulated domestic wastewater, a porous biofilm DM was formed on support materials. As a result, the transmembrane pressure (TMP) did not increase (< 10 Pa) during the 97 days' experiment and the effluent turbidity was consistently lower than 1.0 NTU. When sands (1.3-69.2 µm; 50 mg/L) were the only inorganic particles contained in wastewater, the effluent turbidity became instable and ranged from 0.31 to 3.88 NTU, probably because the DM structures were disturbed by sand scouring. The natural clays (0.5-2.7 µm) in wastewater were very liable to deposit on the support materials of DMBRs to form thick and compact DMs with greater contents of biomass and EPS, especially co-existing with sands. Due to the existence of natural clays, the DM porosity decreased significantly and rapid rising in TMP occurred frequently. This study demonstrated that pure biofilms without containing inorganic particles were ideal materials for DMs, which could achieve long-term stable operation with low effluent turbidity (< 1 NTU) and low TMP (< 10 Pa), while inorganic particles with any size could deteriorate the filtration performance. Therefore, removing the inorganic particles in wastewater as many as possible prior DMBR is critically important for achieving long-term stable operation.

10.
Chemosphere ; 271: 129813, 2021 May.
Artigo em Inglês | MEDLINE | ID: mdl-33556632

RESUMO

Dynamic membrane bioreactors mainly rely on the in-situ formed biofilms on support materials to reject fine particles in water. The development of irremovable biofilms on support materials can decrease the cleaning efficiency when removing the unwanted biofilms with low permeability by water flushing. In the present study, the initial formed biofilms on support materials at 5-day solids retention time (SRT) were removable by water flushing. After repeated cleaning with off-line water flushing during operation, however, irremovable biofilms were developed gradually inside the mesh pores and thus, rapid rising in transmembrane pressure occurred in every one to three days. At 20-day SRT, the biofilms formed on support materials with the same operation time were still removable. Therefore, both low SRT and repeated water flushing promoted the formation of irremovable biofilms on support materials. Further study found that the composition and microbial community between the irremovable and removable biofilms were significantly different, which differentiated the biofilm adhesion and removability. The irremovable biofilms had a greater faction of proteins (49.0%) and ß-d-glucopyranose polysaccharides (17.8%) in extracellular polymeric substance (EPS), while the removable biofilms had a greater fraction of α-d-glucopyranose polysaccharides. After repeated cleaning with off-line water flushing during operation, Nitrospiraceae was selectively enriched in the irremovable biofilms at a relative abundance of 39.1%, which could have resulted in the particular EPS matrix that strengthened the biofilm adhesion.


Assuntos
Microbiota , Água , Biofilmes , Reatores Biológicos , Matriz Extracelular de Substâncias Poliméricas , Membranas Artificiais
11.
Artigo em Inglês | MEDLINE | ID: mdl-33627014

RESUMO

Objectives: Durvalumab plus chemotherapy could significantly improve overall survival compared with chemotherapy alone in the first-line treatment of extensive-stage small-cell lung cancer (SCLC). However, its long-term economic outcomes remain unclear yet. This study aimed to evaluate the cost-effectiveness of adding durvalumab to first-line chemotherapy for extensive-stage SCLC from the perspective of the Chinese health-care system.Methods: A decision-analytic model with 10-year horizon was developed to estimate the health and economic outcomes of adding durvalumab to first-line treatment for extensive-stage SCLC. The primary outcomes included total costs, life years (LYs), quality-adjusted life-years (QALYs), and incremental cost-effectiveness ratio (ICER). Costs and utility values were obtained from the published literature. A scenario analysis for a patient assistance program (PAP) was conducted. Sensitivity analyses were performed to explore the robustness of the model outcomes.Results: Durvalumab plus chemotherapy yielded additional 0.25 QALYs, with incremental costs of 76,354 USD, resulting in an ICER of 302,051 USD/QALY compared with chemotherapy alone, when PAP was available, the ICER was 192,591 USD/QALY. Sensitivity analyses confirmed the robustness of model outcomes.Conclusion: Adding durvalumab to first-line chemotherapy for extensive-stage small-cell lung cancer is unlikely to be cost-effectiveness in China.

12.
ACS Sens ; 6(3): 593-612, 2021 03 26.
Artigo em Inglês | MEDLINE | ID: mdl-33544999

RESUMO

COVID-19, caused by the SARS-CoV-2 virus, has developed into a global health crisis, causing over 2 million deaths and changing people's daily life the world over. Current main-stream diagnostic methods in the laboratory include nucleic acid PCR tests and direct viral antigen tests for detecting active infections, and indirect human antibody tests specific to SARS-CoV-2 to detect prior exposure. In this Perspective, we briefly describe the PCR and antigen tests and then focus mainly on existing antibody tests and their limitations including inaccuracies and possible causes of unreliability. False negatives in antibody immunoassays can arise from assay formats, selection of viral antigens and antibody types, diagnostic testing windows, individual variance, and fluctuation in antibody levels. Reasons for false positives in antibody immunoassays mainly involve antibody cross-reactivity from other viruses, as well as autoimmune disease. The spectrum bias has an effect on both the false negatives and false positives. For assay developers, not only improvement of assay formats but also selection of viral antigens and isotopes of human antibodies need to be carefully considered to improve sensitivity and specificity. For clinicians, the factors influencing the accuracy of assays must be kept in mind to test patients using currently imperfect but available tests with smart tactics and realistic interpretation of the test results.


Assuntos
Anticorpos Antivirais/sangue , /imunologia , Antígenos Virais/sangue , /imunologia , Reações Falso-Negativas , Reações Falso-Positivas , Humanos , Imunoensaio
13.
J Hazard Mater ; 411: 125008, 2021 Jun 05.
Artigo em Inglês | MEDLINE | ID: mdl-33445047

RESUMO

Rational design of fiber-shaped gas sensors with both excellent mechanical properties and sensing performance is of great significance for boosting future portable and wearable sensing electronics, however, it is still a challenge. Herein, we develop a novel fiber-shaped hydrogen (H2) sensor by directly electrochemically growing palladium (Pd) sensing layer on conductive poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) fiber electrode. This approach produces free-standing functional fiber (PEDOT:PSS@Pd) with promising mechanical features of flexibility, light weight, knittability and high mechanical strength, and good H2 sensing performance at room temperature. The PEDOT:PSS@Pd fiber sensor exhibits short response time of 34 (± 6) s@1% and 19 (± 4) s@4% H2 and excellent cycling stability. In addition, the fiber sensor remains good sensing behavior under different mechanical bending states, showing potential for constructing wearable sensor devices for timely H2 leak detection. Therefore, this work has provided a smart design strategy of fiber-based gas sensor, offering an effective sensing platform and is believed to stimulate the development of wearable electronics.

14.
Int Urol Nephrol ; 53(5): 985-997, 2021 May.
Artigo em Inglês | MEDLINE | ID: mdl-33389461

RESUMO

BACKGROUND: Anemia is a common complication for patients with kidney disease. Roxadustat is an oral hypoxia-inducible factor (HIF) prolyl hydroxylase inhibitor (PHI), which is a newly approved oral drug for anemia. We performed this study to build evidence regarding efficacy and safety of roxadustat in kidney disease patients with or without dialysis. METHODS: We searched the databases of PubMed, Embase, Cochrane library and clinicaltrials.gov from the inception to July 20, 2020. The randomized controlled trials (RCTs) which compared roxadustat with placebo or other therapies in the treatment of anemia in kidney disease patients were included. Data were extracted from eligible studies and pooled in a meta-analysis model using RevMan5.3 and stata13.0 software. RESULTS: Eight RCTs with 1010 patients were included in our analysis. We found that roxadustat significantly increased hemoglobin (Hb) level (1.10 g/dL, 95% CI [0.52 g/dL, 1.67 g/dL], p = 0.0002), total iron-binding capacity (TIBC) (58.71 µg/dL, 95% CI [44.10 µg/dL, 73.32 µg/dL], p < 0.00001), iron level (9.28 µg/dL, 95% CI [0.11 µg/dL, 18.45 µg/dL], p = 0.05) compared with control group in kidney disease patients. In addition, our result showed that a significant reduction in hepcidin level (- 31.96 ng/mL, 95% CI [- 35.05 ng/mL, - 28.87 ng/mL], p < 0.00001), ferritin (- 44.82 ng/mL, 95% CI [- 64.42 ng/mL, - 25.23 ng/mL], p < 0.00001) was associated with roxadustat. No difference was found between roxadustat and control group in terms of oral iron supplementation, adverse events (AEs), serious adverse events (SAEs), infection, myocardial infraction, stroke, heart failure and death. CONCLUSIONS: Roxadustat has higher mean Hb level than placebo or EPO. Due to the short follow-up period and the lack of critical data, more RCTs are needed to prove long-term safety and effectiveness of roxadustat in the future.

15.
Chem Asian J ; 16(7): 761-768, 2021 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-33484093

RESUMO

Core-shell nanocolloids with tailored physical and chemical merits hold attractive potential for energy-related applications. Herein, core-shell nanocolloids composed of zinc/copper sulfide (ZnS/CuSx ) shells and silica (SiO2 ) cores were fabricated by a template-engaged synthetic method. Interestingly, the sizes of SiO2 cores can be tuned by different sulfurization time. In virtue of the light scattering and reflection on the SiO2 surface, the efficiencies of light capture by ZnS/Cu2 S shells were highly dependent on the SiO2 sizes. The as-fabricated SiO2 @ZnS/Cu2 S with a core size of 205 nm exhibited the highest and broadest absorption within a light wavelength of 380-700 nm. In virtue of the structural and componential features of these nanocolloids, maximum photocatalytic hydrogen (H2 ) production rates of 2968 and 1824 µmol h-1 g-1 under UV-vis and visible light have been delivered, respectively. This work may provide some evidence for the design and fabrication of core-shell nanomaterials to convert solar energy to green fuels.

16.
Sci Total Environ ; 760: 143946, 2021 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-33341608

RESUMO

Rapid industrialization, urbanization, and population growth have led to the common occurrence of black-stinking urban rivers. Assessing regional anthropogenic influences is beneficial to develop effective remediation strategies. This study comprehensively investigated the occurrence and fate of linear alkylbenzenes (LABs) as molecular markers of anthropogenic influences in three media (filtered water, suspended particulate matter (SPM), and sediment) in a highly urbanized river (Baihaimian River) in Guangzhou, South China. The concentrations of LABs ranged from 41 to 215 ng/L in the dissolved phase, from 7122 to 46,640 ng/g dry weight in the SPM phase, and from 73 to 3650 ng/g dry weight in surface sediments (0-10 cm depth). The spatial distribution of LABs was probably affected by the surrounding environment, river flux, and sediment properties. No biotransformation of LABs in water samples and a slight biotransformation in sediments were observed. Significant correlations were found between total nitrogen, ammonia nitrogen, and LABs in river water, indicating the same domestic wastewater sources. The positive correlation between total organic carbon (TOC) and LABs in sediments suggested that TOC worked as the controlling factor for the redistribution of LABs and that local sewage discharge was the dominant TOC input. The total mass inventory of LABs in sediment in Baihaimian River was 21 kg. The total mass of LABs released into Baihaimian River was 183 kg per year, among them, 63% was discharged into the adjacent Liuxi River.

17.
Artigo em Inglês | MEDLINE | ID: mdl-33267953

RESUMO

Development of well-designed bifunctional electrocatalysts with high activity for OER (oxygen evolution reaction) and ORR (oxygen reduction reaction) are a crucial topic owing to their promising applications in rechargeable Zinc (Zn)-air battery. Herein, a facile adsorption-pyrolyzation strategy is proposed for preparing ultrafine Ni nanoparticles anchored on carbon nanofiber (Ni/CNF), which derives from pyrolyzation of bacterial cellulose (BC) (with pre-adsorbed of Ni2+) via a two-step heat-treatment procedure (firstly 360 â„ƒ, and then 750 â„ƒ) (Ni/CNF-750) and used as an excellent oxygen electrocatalyst for flexible all solid-state Zn-air cell. The resultant ultrafine Ni/CNF-750 with plentiful pore structure and relatively high specific surface area of 449.0 m2 g-1, delivering overpotential of 293 mV at current density of 10 mA cm-2 for OER, obtaining an onset potential of 0.93 V vs. RHE and half-wave potential of 0.76 V vs. RHE for ORR. Moreover, a home-made flexible all solid-state battery is constructed by using Ni/CNF-750 as air electrodes, which provides a power density of 56.8 mW cm-2 and wonderful cycling durability with maintaining 50 cycles, and can drive a light-emitting-diode (LED) device. Our work may provides a reliable approach for fabricating ultrafine metal nanoparticles anchored on carbon based substrate with high activity for next-generation energy conversion and storage devices.

18.
Nat Commun ; 11(1): 6214, 2020 12 04.
Artigo em Inglês | MEDLINE | ID: mdl-33277480

RESUMO

Radioprotectors for acute injuries caused by large doses of ionizing radiation are vital to national security, public health and future development of humankind. Here, we develop a strategy to explore safe and efficient radioprotectors by combining Hantzsch's reaction, high-throughput methods and polymer chemistry. A water-soluble polymer with low-cytotoxicity and an excellent anti-radiation capability has been achieved. In in vivo experiments, this polymer is even better than amifostine, which is the only approved radioprotector for clinical applications, in effectively protecting zebrafish embryos from fatally large doses of ionizing radiation (80 Gy X-ray). A mechanistic study also reveals that the radioprotective ability of this polymer originates from its ability to efficiently prevent DNA damage due to high doses of radiation. This is an initial attempt to explore polymer radioprotectors via a multi-component reaction. It allows exploiting functional polymers and provides the underlying insights to guide the design of radioprotective polymers.

19.
ACS Appl Mater Interfaces ; 12(47): 52922-52928, 2020 Nov 25.
Artigo em Inglês | MEDLINE | ID: mdl-33170630

RESUMO

Constructing a nanocomposite to introduce a coherent interface is an effective way to improve the property of thermoelectric material. Here, a series composites of Bi0.48Sb1.52Te3-x wt % Sb2Te3 (x = 0, 0.3, 0.5, 0.8, and 1.0) were synthesized, where the hydrothermally prepared Sb2Te3 nanosheets were intimately wrapped in the solid-state-reacted Bi0.48Sb1.52Te3 matrix. The formation of a coherent interface was observed and confirmed by the scanning electron microscopy characterization. As the Sb2Te3 content was over 0.5 wt %, the carrier mobility could increase by 26%, while the carrier concentration decreased by 9% compared to those of the pure matrix at 300 K, enhancing the power factor to 40.1 µW/cm K2. Moreover, the Bi0.48Sb1.52Te3-0.5 wt % Sb2Te3 sample exhibited a reduced lattice thermal conductivity of 0.83 W/m K at room temperature, resulting from the strengthened phonon scattering by interfaces. Combined with the manipulations of both the electronic and thermal transport by constructing a coherent interface, a maximum ZT of 1.05 was obtained in the x = 0.5 composite at 300 K, and it was improved by 20% compared with the result of the Bi0.48Sb1.52Te3 matrix.

20.
Sheng Wu Yi Xue Gong Cheng Xue Za Zhi ; 37(5): 786-792, 2020 Oct 25.
Artigo em Chinês | MEDLINE | ID: mdl-33140601

RESUMO

As drug carriers, magnetic nanoparticles can specifically bind to tumors and have the potential for targeted therapy. It is of great significance to explore non-invasive imaging methods that can detect the distribution of magnetic nanoparticles. Based on the mechanism that magnetic nanoparticles can generate ultrasonic waves through the pulsed magnetic field excitation, the sound pressure wave equation containing the concentration information of magnetic nanoparticles was derived. Using the finite element method and the analytical solution, the consistent transient pulsed magnetic field was obtained. A three-dimensional simulation model was constructed for the coupling calculation of electromagnetic field and sound field. The simulation results verified that the sound pressure waveform at the detection point reflected the position of magnetic nanoparticles in biological tissue. Using the sound pressure data detected by the ultrasonic transducer, the B-scan imaging of the magnetic nanoparticles was achieved. The maximum error of the target area position was 1.56%, and the magnetic nanoparticles regions with different concentrations were distinguished by comparing the amplitude of the boundary signals in the image. Studies in this paper indicate that B-scan imaging can quickly and accurately obtain the dimensional and positional information of the target region and is expected to be used for the detection of magnetic nanoparticles in targeted therapy.

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