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1.
Environ Sci Technol ; 2024 Apr 23.
Artigo em Inglês | MEDLINE | ID: mdl-38653761

RESUMO

Nitrous oxide (N2O) is a potent greenhouse gas with a high global warming potential, emphasizing the critical need to develop efficient elimination methods. Electrocatalytic N2O reduction reaction (N2ORR) stands out as a promising approach, offering room temperature conversion of N2O to N2 without the production of NOx byproducts. In this study, we present the synthesis of a copper-based single-atom catalyst featuring atomic Cu on nitrogen-doped carbon black (Cu1-NCB). Attributed to the highly dispersed single-atom Cu sites and the effective suppression of the hydrogen evolution reaction, Cu1-NCB demonstrated an optimal N2 faradaic efficiency (82.1%) and yield rate (3.53 mmol h-1 mgmetal-1) at -0.2 and -0.5 V vs RHE, respectively, outperforming previously reported N2ORR electrocatalysts. Further, a gas diffusion electrode cell was employed to improve mass transfer and achieved a 28.6% conversion rate of 30% N2O with only a 14 s residence time, demonstrating the potential for practical application. Density functional theory calculations identified Cu-N4 as the crucial active site for N2ORR, highlighting the significance of the unsaturated coordination and metal-support electronic structure. O-terminal adsorption of N2O was favored, and the dissociative adsorption (*ON2 → *O + N2) was the rate-determining step. These findings reveal the broad prospects of N2O decomposition via electrocatalysis.

2.
Environ Sci Technol ; 58(12): 5557-5566, 2024 Mar 26.
Artigo em Inglês | MEDLINE | ID: mdl-38412381

RESUMO

Wet flue gas denitrification offers a new route to convert industrial nitrogen oxides (NOx) into highly concentrated nitrate wastewater, from which the nitrogen resource can be recovered to ammonia (NH3) via electrochemical nitrate reduction reactions (NITRRs). Low-cost, scalable, and efficient cathodic materials need to be developed to enhance the NH3 production rate. Here, in situ electrodeposition was adopted to fabricate a foamy Cu-based heterojunction electrode containing both Cu-defects and oxygen vacancy loaded Cu2O (OVs-Cu2O), which achieved an NH3 yield rate of 3.59 mmol h-1 cm-2, NH3 Faradaic efficiency of 99.5%, and NH3 selectivity of 100%. Characterizations and theoretical calculations unveiled that the Cu-defects and OVs-Cu2O heterojunction boosted the H* yield, suppressed the hydrogen evolution reaction (HER), and served as dual reaction sites to coherently match the tandem reactions kinetics of NO3-to-NO2 and NO2-to-NH3. An integrated system was further built to combine wet flue gas denitrification and desulfurization, simultaneously converting NO and SO2 to produce the (NH4)2SO4 fertilizer. This study offers new insights into the application of low-cost Cu-based cathode for electrochemically driven wet denitrification wastewater valorization.


Assuntos
Amônia , Águas Residuárias , Nitratos/química , Dióxido de Nitrogênio , Desnitrificação , Eletrodos
3.
Environ Sci Technol ; 57(47): 19054-19063, 2023 Nov 28.
Artigo em Inglês | MEDLINE | ID: mdl-37943016

RESUMO

Peroxymonosulfate (PMS)-based electrochemical advanced oxidation processes (EAOPs) have received widespread attention in recent years, but the precise nature of PMS activation and its impact on the overall process performance remain poorly understood. This study presents the first demonstration of the critical role played by the oxygen reduction reaction in the effective utilization of PMS and the subsequent enhancement of overall pollutant remediation. We observed the concurrent generation of H2O2 via oxygen reduction during the cathodic PMS activation by a model nitrogen-doped carbon nanotube catalyst. A complex interplay between H2O2 generation and PMS activation, as well as a locally increased pH near the electrode due to the oxygen reduction reaction, resulted in a SO4•-/•OH-mixed oxidation environment that facilitated pollutant degradation. The findings of this study highlight a unique dependency between PMS-driven and H2O2-driven EAOPs and a new perspective on a previously unexplored route for further enhancing PMS-based treatment processes.


Assuntos
Poluentes Ambientais , Peróxido de Hidrogênio , Peróxidos , Oxirredução , Oxigênio
4.
Regen Ther ; 24: 507-514, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-37841661

RESUMO

The facial nerve, also known as the seventh cranial nerve, is critical in controlling the movement of the facial muscles. It is responsible for all facial expressions, such as smiling, frowning, and moving the eyebrows. However, damage to this nerve can occur for a variety of reasons, including maxillofacial surgery, trauma, tumors, and infections. Facial nerve injuries can cause severe functional impairment and can lead to different degrees of facial paralysis, significantly affecting the quality of life of patients. Over the past ten years, significant progress has been made in the field of facial nerve repair. Different approaches, including direct suture, autologous nerve grafts, and tissue engineering, have been utilized for the repair of facial nerve injury. This article mainly summarizes the clinical methods and basic research progress of facial nerve repair in the past ten years.

5.
Environ Sci Technol ; 57(37): 14091-14099, 2023 09 19.
Artigo em Inglês | MEDLINE | ID: mdl-37643464

RESUMO

Wet denitrification is a promising approach to control nitrogen oxides (NOx) produced in fossil fuel combustion. Yet, the highly concentrated nitrite (NO2-) wastewater generated poses a major threat to the aqueous environment. Here, iridium nanoclusters (d = 1.63 nm) deposited on TiO2 were applied for NO2- reduction to ammonia (NRA), showing an exceptional NH4+ selectivity of 95% and a production rate of 20.51 mgN·L-1·h-1, which held significant potential for NO2- wastewater purification and ammonia resource recovery. Notably, an interesting non-first-order NO2- hydrogenation kinetics was observed, which was further confirmed to result from the competitive adsorption mechanism between H2 and NO2- over iridium. The NRA pathways on the Ir(111) surface were explored via density functional theory calculations with the NO2-* → NO* → HNO* → HNOH* → H2NOH* → NH2* → NH3* identified as the most energetically favorable pathway and the NO* → HNO* confirmed as the rate-determining step. In situ DRIFTS further experimentally verified the generation of HNO* intermediate during NO* hydrogenation on Ir(111). To verify NRA kinetics at varied NO2- concentrations or H2 pressures, a kinetic model was derived based on the Langmuir-Hinshelwood competitive adsorption mechanism. These findings provide mechanistic insights into the NRA pathways on Ir nanocatalysts, which will be beneficial for wet denitrification waste stream decontamination and valorization.


Assuntos
Amônia , Nitritos , Hidrogenação , Adsorção , Irídio , Dióxido de Nitrogênio
6.
ACS Sens ; 8(7): 2471-2492, 2023 07 28.
Artigo em Inglês | MEDLINE | ID: mdl-37368490

RESUMO

The demand for monitoring chemical and physical information surrounding, air quality, and disease diagnosis has propelled the development of devices for gas sensing that are capable of translating external stimuli into detectable signals. Metal-organic frameworks (MOFs), possessing particular physiochemical properties with designability in topology, specific surface area, pore size and/or geometry, potential functionalization, and host-guest interactions, reveal excellent development promises for manufacturing a variety of MOF-coated sensing devices for multitudinous applications including gas sensing. The past years have witnessed tremendous progress on the preparation of MOF-coated gas sensors with superior sensing performance, especially high sensitivity and selectivity. Although limited reviews have summarized different transduction mechanisms and applications of MOF-coated sensors, reviews summarizing the latest progress of MOF-coated devices under different working principles would be a good complement. Herein, we summarize the latest advances of several classes of MOF-based devices for gas sensing, i.e., chemiresistive sensors, capacitors, field-effect transistors (FETs) or Kelvin probes (KPs), electrochemical, and quartz crystal microbalance (QCM)-based sensors. The surface chemistry and structural characteristics were carefully associated with the sensing behaviors of relevant MOF-coated sensors. Finally, challenges and future prospects for long-term development and potentially practical application of MOF-coated sensing devices are pointed out.


Assuntos
Estruturas Metalorgânicas , Comércio
7.
Molecules ; 28(9)2023 May 04.
Artigo em Inglês | MEDLINE | ID: mdl-37175275

RESUMO

Recently, single-atom catalysts (SACs) have attracted wide attention in the field of environmental engineering. Compared with their nanoparticle counterparts, SACs possess high atomic efficiency, unique catalytic activity, and selectivity. This review summarizes recent studies on the environmental remediation applications of SACs in (1) gaseous: volatile organic compounds (VOCs) treatment, NOx reduction, CO2 reduction, and CO oxidation; (2) aqueous: Fenton-like advanced oxidation processes (AOPs), hydrodehalogenation, and nitrate/nitrite reduction. We present the treatment activities and reaction mechanisms of various SACs and propose challenges and future opportunities. We believe that this review will provide constructive inspiration and direction for future SAC research in environmental engineering.

8.
ACS Catal ; 13(10): 6804-6812, 2023 May 19.
Artigo em Inglês | MEDLINE | ID: mdl-37234352

RESUMO

The occurrence of high concentrations of nitrate in various water resources is a significant environmental and human health threat, demanding effective removal technologies. Single atom alloys (SAAs) have emerged as a promising bimetallic material architecture in various thermocatalytic and electrocatalytic schemes including nitrate reduction reaction (NRR). This study suggests that there exists a stark contrast between thermocatalytic (T-NRR) and electrocatalytic (E-NRR) pathways that resulted in dramatic differences in SAA performances. Among Pd/Cu nanoalloys with varying Pd-Cu ratios from 1:100 to 100:1, Pd/Cu(1:100) SAA exhibited the greatest activity (TOFPd = 2 min-1) and highest N2 selectivity (94%) for E-NRR, while the same SAA performed poorly for T-NRR as compared to other nanoalloy counterparts. DFT calculations demonstrate that the improved performance and N2 selectivity of Pd/Cu(1:100) in E-NRR compared to T-NRR originate from the higher stability of NO3* in electrocatalysis and a lower N2 formation barrier than NH due to localized pH effects and the ability to extract protons from water. This study establishes the performance and mechanistic differences of SAA and nanoalloys for T-NRR versus E-NRR.

9.
RSC Adv ; 13(22): 15165-15173, 2023 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-37213344

RESUMO

Dichloromethane (DCM), a typical representative of chlorinated volatile organic compounds (CVOCs), is usually exhausted along with other volatile organic compounds (VOCs), such as toluene and ethyl acetate, in industrial factories. To address the complexity of the components, the large variation in concentration of each component and the water content of the exhaust gases emitted from the pharmaceutical and chemical industries, the adsorption characteristics of DCM, toluene (MB), and ethyl acetate (EAC) vapors on hypercrosslinked polymeric resins (NDA-88) were studied by dynamic adsorption experiments. Furthermore, the adsorption characteristics of NDA-88 for binary vapor systems of DCM-MB and DCM-EAC at different concentration ratios and the nature of the interaction force with the three VOCs were explored. NDA-88 was found to be suitable for treating binary vapor systems of DCM mixed with low concentrations of MB/EAC, and a small quantity of adsorbed MB or EAC would promote the adsorption of DCM by NDA-88, which is attributed to the microporous filling phenomenon. Finally, the influence of humidity on the adsorption performance of binary vapor systems for NDA-88 and the regeneration adsorption performance of NDA-88 were investigated. The presence of water steam shortened the penetration times of DCM, EAC, and MB, regardless of whether it was in the DCM-EAC or DCM-MB two-component systems. This study has identified a commercially available hypercrosslinked polymeric resin NDA-88, which has excellent adsorption performance and regeneration capacity for both single-component DCM gas and a binary mixture of DCM-low-concentration MB/EAC, providing experimental guidance for the treatment of emissions from pharmaceutical and chemical industries by adsorption.

10.
Proc Natl Acad Sci U S A ; 120(11): e2217703120, 2023 Mar 14.
Artigo em Inglês | MEDLINE | ID: mdl-36877847

RESUMO

The release of wastewaters containing relatively low levels of nitrate (NO3-) results in sufficient contamination to induce harmful algal blooms and to elevate drinking water NO3- concentrations to potentially hazardous levels. In particular, the facile triggering of algal blooms by ultra-low concentrations of NO3- necessitates the development of efficient methods for NO3- destruction. However, promising electrochemical methods suffer from weak mass transport under low reactant concentrations, resulting in long treatment times (on the order of hours) for complete NO3- destruction. In this study, we present flow-through electrofiltration via an electrified membrane incorporating nonprecious metal single-atom catalysts for NO3- reduction activity enhancement and selectivity modification, achieving near-complete removal of ultra-low concentration NO3- (10 mg-N L-1) with a residence time of only a few seconds (10 s). By anchoring Cu single atoms supported on N-doped carbon in a carbon nanotube interwoven framework, we fabricate a free-standing carbonaceous membrane featuring high conductivity, permeability, and flexibility. The membrane achieves over 97% NO3- removal with high N2 selectivity of 86% in a single-pass electrofiltration, which is a significant improvement over flow-by operation (30% NO3- removal with 7% N2 selectivity). This high NO3- reduction performance is attributed to the greater adsorption and transport of nitric oxide under high molecular collision frequency coupled with a balanced supply of atomic hydrogen through H2 dissociation during electrofiltration. Overall, our findings provide a paradigm of applying a flow-through electrified membrane incorporating single-atom catalysts to improve the rate and selectivity of NO3- reduction for efficient water purification.

11.
Proc Natl Acad Sci U S A ; 120(9): e2216879120, 2023 Feb 28.
Artigo em Inglês | MEDLINE | ID: mdl-36802414

RESUMO

Atomic dispersion of metal catalysts on a substrate accounts for the increased atomic efficiency of single-atom catalysts (SACs) in various catalytic schemes compared to the nanoparticle counterparts. However, lacking neighboring metal sites has been shown to deteriorate the catalytic performance of SACs in a few industrially important reactions, such as dehalogenation, CO oxidation, and hydrogenation. Metal ensemble catalysts (Mn), an extended concept to SACs, have emerged as a promising alternative to overcome such limitation. Inspired by the fact that the performance of fully isolated SACs can be enhanced by tailoring their coordination environment (CE), we here evaluate whether the CE of Mn can also be manipulated in order to enhance their catalytic activity. We synthesized a set of Pd ensembles (Pdn) on doped graphene supports (Pdn/X-graphene where X = O, S, B, and N). We found that introducing S and N onto oxidized graphene modifies the first shell of Pdn converting Pd-O to Pd-S and Pd-N, respectively. We further found that the B dopant significantly affected the electronic structure of Pdn by serving as an electron donor in the second shell. We examined the performance of Pdn/X-graphene toward selective reductive catalysis, such as bromate reduction, brominated organic hydrogenation, and aqueous-phase CO2 reduction. We observed that Pdn/N-graphene exhibited superior performance by lowering the activation energy of the rate-limiting step, i.e., H2 dissociation into atomic hydrogen. The results collectively suggest controlling the CE of SACs in an ensemble configuration is a viable strategy to optimize and enhance their catalytic performance.

12.
Nat Commun ; 13(1): 5946, 2022 Oct 08.
Artigo em Inglês | MEDLINE | ID: mdl-36209165

RESUMO

Power conversion efficiency and long-term stability are two critical metrics for evaluating the commercial potential of organic photovoltaics. Although the field has witnessed a rapid progress of efficiency towards 19%, the intrinsic trade-off between efficiency and stability is still a challenging issue for bulk-heterojunction cells due to the very delicate crystallization dynamics of organic species. Herein, we developed a class of non-fullerene acceptors with varied side groups as an alternative to aliphatic chains. Among them, the acceptors with conjugated side groups show larger side-group torsion and more twisted backbone, however, they can deliver an efficiency as high as 18.3% in xylene-processed cells, which is among the highest values reported for non-halogenated solvent processed cells. Meanwhile, decent thermal/photo stability is realized for these acceptors containing conjugated side groups. Through the investigation of the geometry-performance-stability relationship, we highlight the importance of side-group steric hinderance of acceptors in achieving combined high-performance, stable, and eco-friendly organic photovoltaics.

13.
Annu Rev Phys Chem ; 73: 453-477, 2022 04 20.
Artigo em Inglês | MEDLINE | ID: mdl-35113740

RESUMO

All solid materials are created via nucleation. In this evolutionary process, nuclei form in solution or at interfaces, expand by monomeric growth and oriented attachment, and undergo phase transformation. Nucleation determines the location and size of nuclei, whereas growth controls the size, shape, and aggregation of newly formed nanoparticles. These physical properties of nanoparticles can affect their functionalities, reactivities, and porosities, as well as their fate and transport. Recent advances in nanoscale analytical technologies allow in situ real-time observations, enabling us to uncover the molecular nature of nuclei and the critical controlling factors for nucleation and growth. Although a single theory cannot yet fully explain such evolving processes, we have started to better understand how both classical andnonclassical theories can work together, and we have begun to recognize the importance of connecting these theories. This review discusses the recent convergence of knowledge about the nucleation and growth of nanoparticles.


Assuntos
Nanopartículas
14.
Environ Sci Technol ; 56(2): 1365-1375, 2022 01 18.
Artigo em Inglês | MEDLINE | ID: mdl-34958567

RESUMO

Electrocatalysis has been proposed as a versatile technology for wastewater treatment and reuse. While enormous attention has been centered on material synthesis and design, the practicality of such catalyst materials remains clouded by a lack of both stability assessment protocols and understanding of deactivation mechanisms. In this study, we develop a protocol to identify the wastewater constituents most detrimental to electrocatalyst performance in a timely manner and elucidate the underlying phenomena behind these losses. Synthesized catalysts are electrochemically investigated in various electrolytes based on real industrial effluent characteristics and methodically subjected to a sequence of chronopotentiometric stability tests, in which each stage presents harsher operating conditions. To showcase, oxidized carbon black is chosen as a model catalyst for the electrosynthesis of H2O2, a precursor for advanced oxidation processes. Results illustrate severe losses in catalyst activity and/or selectivity upon the introduction of metal pollutants, namely magnesium and zinc. The insights garnered from this protocol serve to translate lab-scale electrocatalyst developments into practical technologies for industrial water treatment purposes.


Assuntos
Poluentes Químicos da Água , Purificação da Água , Catálise , Peróxido de Hidrogênio , Oxirredução , Águas Residuárias , Poluentes Químicos da Água/análise , Purificação da Água/métodos
15.
Environ Sci Technol ; 56(2): 1341-1351, 2022 01 18.
Artigo em Inglês | MEDLINE | ID: mdl-34964609

RESUMO

We introduce a new graphene oxide (GO)-based membrane architecture that hosts cobalt catalysts within its nanoscale pore walls. Such an architecture would not be possible with catalysts in nanoscale, the current benchmark, since they would block the pores or alter the pore structure. Therefore, we developed a new synthesis procedure to load cobalt in an atomically dispersed fashion, the theoretical limit in material downsizing. The use of vitamin C as a mild reducing agent was critical to load Co as dispersed atoms (Co1), preserving the well-stacked 2D structure of GO layers. With the addition of peroxymonosulfate (PMS), the Co1-GO membrane efficiently degraded 1,4-dioxane, a small, neutral pollutant that passes through nanopores in single-pass treatment. The observed 1,4-dioxane degradation kinetics were much faster (>640 times) than the kinetics in suspension and the highest among reported persulfate-based 1,4-dioxane destruction. The capability of the membrane to reject large organic molecules alleviated their effects on radical scavenging. Furthermore, the advanced oxidation also mitigated membrane fouling. The findings of this study present a critical advance toward developing catalytic membranes with which two distinctive and complementary processes, membrane filtration and advanced oxidation, can be combined into a single-step treatment.


Assuntos
Poluentes Ambientais , Grafite , Catálise , Cobalto/química
16.
Environ Sci Technol ; 55(19): 13306-13316, 2021 10 05.
Artigo em Inglês | MEDLINE | ID: mdl-34545738

RESUMO

In this study, we loaded Pd catalysts onto a reduced graphene oxide (rGO) support in an atomically dispersed fashion [i.e., Pd single-atom catalysts (SACs) on rGO or Pd1/rGO] via a facile and scalable synthesis based on anchor-site and photoreduction techniques. The as-synthesized Pd1/rGO significantly outperformed the Pd nanoparticle (Pdnano) counterparts in the electrocatalytic hydrodechlorination of chlorinated phenols. Downsizing Pdnano to Pd1 leads to a substantially higher Pd atomic efficiency (14 times that of Pdnano), remarkably reducing the cost for practical applications. The unique single-atom architecture of Pd1 additionally affects the desorption energy of the intermediate, suppressing the catalyst poisoning by Cl-, which is a prevalent challenge with Pdnano. Characterization and experimental results demonstrate that the superior performance of Pd1/rGO originates from (1) enhanced interfacial electron transfer through Pd-O bonds due to the electronic metal-support interaction and (2) increased atomic H (H*) utilization efficiency by inhibiting H2 evolution on Pd1. This work presents an important example of how the unique geometric and electronic structure of SACs can tune their catalytic performance toward beneficial use in environmental remediation applications.


Assuntos
Recuperação e Remediação Ambiental , Paládio , Catálise
17.
Microorganisms ; 9(7)2021 Jun 22.
Artigo em Inglês | MEDLINE | ID: mdl-34206411

RESUMO

Since doenjang quality depends on the bacterial composition, which ambient bacteria in the environment and production conditions influence, a complete understanding of the bacteria community in traditionally madetraditionally made doenjang (TMD) from different regions is needed. We aimed to investigate the bacteria composition and quality of TMD in the following areas: Chonbuk (CB), Chonnam (CN), Kyungsang (KS), Kangwon (KW), Chungchung (CC) provinces, and Jeju island (JJ) of Korea. Twenty-nine TMD samples from different regions were used to assess biogenic amine contents, bacteria composition using next-generation methods, and metabolic functions of the bacteria using Picrust2. Bacillus spp. were isolated, and their antioxidant and fibrinolytic activities were determined. Most TMD contained high amounts of beneficial bacteria (Bacillus, Lactobacillus, Pediococcus and Weissella). However, some KS samples contained harmful bacteria (Cronobacter, Proteus and Acinetobacter) and less beneficial B. velezensis bacteria. There was no similarity among the regional groups, and each TMD showed a different bacteria composition. Shannon index, α-diversity index, was lower in TMD from JJ and CB than the other areas, but there was no ß-diversity among TMD from the six area groups. Picrust2 analysis revealed that the functional potential for arachidonic acid metabolism was lowest in JJ and CN, that for supporting insulin action was highest in KS and JJ, and that for carbohydrate digestion and absorption was lowest in CB and JJ among all groups (p < 0.05) according to the Kyoto Encyclopedia of Genes and Genomes Orthology. Histamine contents were lower in CN and CC, and tyramine contents did not differ significantly. B. velezensis, B. subtilis, B. licheniformis, B. siamensis, and B. amyloliquefaciens were isolated from TMD. None of the isolated Bacillus spp. contained the B. cereus gene. B. subtilis from CN had the highest fibrinolytic activity, and B. velezensis from CB had the highest antioxidant activity. In conclusion, TMD mainly contained various Bacillus spp., and the predominant one was B. velezensis, which had antioxidant and fibrinolytic activity regardless of the regional origin.

18.
Arch Oral Biol ; 129: 105198, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34167010

RESUMO

OBJECTIVE: This study aimed to investigate that these bacteria counts in the oral cavity were modulated by the recurrent aphthous stomatitis (RAS) status according to age and ethnicity with a systematic review and meta-analysis. DESIGN: The relevant case-control studies were searched in the literature database in English, Korean, and Chinese until June 2020 using keywords, and the literature was screened and collated for Review Manager analysis. Sensitivity analysis and quality check of the included literature were conducted. RESULTS: From the selection process, oral bacteria counts were measured by polymerase chain reaction (PCR) in 8 studies and next-generation sequencing in 4 studies. Healthy control, ulcerative phases of RAS (UC-RAS), non-ulcerative phases of RAS (Non-UC-RAS) groups included 442, 473, and 386 participants in a total of 12 studies. For PCR detection, mean differences (95 % confidence intervals) of Veillonella and Streptococcus counts between the healthy-control and RAS groups were -1.91 (-2.41 ∼ -1.41) and -1.34 (-1.85 ∼ -0.83)(P < 0.0001). The bacteria count results by "Next-generation" sequencing (NGS) and PCR methods were similar. Significantly lower Veillonella and Streptococcus counts were observed in the UC-RAS group than in the non-UC-RAS group (P < 0.0001). Veillonella and Streptococcus count differences between RAS and controls aged ≥30 years were greater than those aged <30 years. At the species level, the prevalence of RAS had a negative relation with Veillonella dispar count. CONCLUSIONS: Counts of Veillonella and Streptococcus are strongly correlated with the recovery and progression of RAS, especially in middle-aged patients. Adjustment of oral microbiota should be considered in the treatment of RAS.


Assuntos
Estomatite Aftosa , Veillonella , Humanos , Pessoa de Meia-Idade , Neisseria , Streptococcus
19.
Adv Mater ; 33(28): e2000922, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32537817

RESUMO

Herein, the recent advances in realizing highly efficient cellulose-based solar evaporators for alleviating the global water crisis are summarized. Fresh water scarcity is one of the most threatening issues for sustainable development. Solar steam generation, which harnesses the abundant sunlight, has been recognized as a sustainable approach to harvest fresh water. In contrast to synthetic polymeric materials that can pose serious negative environmental impacts, cellulose-based materials, owing to their biocompatibility, renewability, and sustainability, are highly attractive for realizing solar steam generators. The molecular and macromolecular features of cellulose and the physicochemical properties of extracted cellulose nanoparticles (cellulose nanocrystals and cellulose nanofibrils (CNF)) and natural cellulose materials (wood and bacterial nanocellulose (BNC)) that make them attractive as supporting substrate materials in solar steam generators are briefly discussed. Recent progress in designing highly efficient cellulose-based solar evaporators, including utilizing extracted cellulose nanoparticles via bottom-up assembly CNF, natural cellulose materials with intrinsic hierarchical structure (wood and BNC), and commercial planar cellulose substrates (air-laid paper, cellulose paper, and cotton fabric) is reviewed. The outstanding challenges that need to be addressed for these materials and devices to be utilized in the real-world and in overcoming global water crisis are also briefly highlighted.

20.
Environ Sci Technol ; 54(19): 12119-12129, 2020 10 06.
Artigo em Inglês | MEDLINE | ID: mdl-32786556

RESUMO

Poorly crystalline iron(III) (hydr)oxide nanoparticles are ubiquitous in environmental systems and play a crucial role in controlling the fate and transport of contaminants. Yet, the thermodynamic and kinetic parameters, e.g., the effective interfacial (α') and apparent activation (Ea) energies, of iron(III) (hydr)oxide nucleation on earth-abundant mineral surfaces have not been determined, which hinders an accurate prediction of iron(III) (hydr)oxide formation and its interactions with other toxic or reactive ions. Here, for the first time, we report experimentally obtained α' and Ea for iron(III) (hydr)oxide nucleation on quartz mineral surfaces by employing a flow-through, time-resolved grazing incidence small-angle X-ray scattering (GISAXS). GISAXS enabled the in situ detection of iron(III) (hydr)oxide nucleation rates under different supersaturations (σ, achieved by varying pH 3.3-3.6) and temperatures (12-35 °C). By quantitative analyses based on classical nucleation theory, α' was obtained to be 34.6 mJ/m2 and Ea was quantified as 32.8 kJ/mol. The fundamental thermodynamic and kinetic parameters obtained here will advance our fundamental understanding of the surface chemistry and nucleation behavior of iron(III) (hydr)oxides in subsurface and water treatment systems as well as their effects on the fate and transport of pollutants in natural and engineered water systems. The in situ flow-through GISAXS method can also be adapted to quantify thermodynamic and kinetic parameters at interfaces for many important solid-liquid environmental systems.


Assuntos
Óxidos , Quartzo , Compostos Férricos , Ferro , Minerais , Água
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