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1.
Front Public Health ; 10: 829176, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35493393

RESUMO

Background: As the epidemic progresses, universal vaccination against COVID-19 has been the trend, but there are still some doubts about the efficacy and safety of COVID-19 vaccines in adolescents, children, and even infants. Purpose: To evaluate the safety, immunogenicity, and efficacy of COVID-19 vaccines in the population aged 0-17 years. Method: A comprehensive search for relevant randomized controlled trials (RCTs) was conducted in PubMed, Embase, and the Cochrane Library from inception to November 9, 2021. All data were pooled by RevMan 5.3 statistical software, with risk ratio (RR) and its 95% confidence interval as the effect measure. This study protocol was registered on PROSPERO (CRD42021290205). Results: There was a total of six randomized controlled trials included in this systematic review and meta-analysis, enrolling participants in the age range of 3-17 years, and containing three types of COVID-19 vaccines. Compared with mRNA vaccines and adenovirus vector vaccines, inactivated vaccines have a more satisfactory safety profile, both after initial (RR 1.40, 95% CI 1.04-1.90, P = 0.03) and booster (RR 1.84, 95% CI 1.20-2.81, P = 0.005) vaccination. The risk of adverse reactions was significantly increased after the first and second doses, but there was no significant difference between the first two doses (RR 1.00, 95%CI 0.99-1.02, P = 0.60). Nevertheless, the two-dose regimen is obviously superior to the single-dose schedule for immunogenicity and efficacy. After booster vaccination, both neutralizing antibodies (RR 144.80, 95%CI 44.97-466.24, P < 0.00001) and RBD-binding antibodies (RR 101.50, 95%CI 6.44-1,600.76, P = 0.001) reach optimal levels, but the cellular immune response seemed not to be further enhanced. In addition, compared with younger children, older children and adolescents were at significantly increased risk of adverse reactions after vaccination, with either mRNA or inactivated vaccines, accompanied by a stronger immune response. Conclusion: The available evidence suggests that the safety, immunogenicity and efficacy of COVID-19 vaccines are acceptable in people aged 3-17 years. However, there is an urgent need for additional multicenter, large-sample studies, especially in younger children under 3 years of age and even in infants, with long-term follow-up data. Systematic Review Registration: https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42021290205, identifier: CRD42021290205.


Assuntos
COVID-19 , Vacinas , Adolescente , COVID-19/prevenção & controle , Vacinas contra COVID-19/efeitos adversos , Criança , Pré-Escolar , Humanos , Estudos Multicêntricos como Assunto , Vacinação
2.
Front Oncol ; 12: 879714, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35494087

RESUMO

Pheochromocytoma is a rare catecholamine-secreting tumor with highly variable clinical presentations. We herein report a patient who presented to the emergency department with precordia pain, elevated myocardial enzymes, T-wave inversions on electrocardiogram and segmental ventricular wall motion abnormalities on echocardiography, which is normally managed as suspected acute coronary syndrome (ACS). However, the urgent coronary angiography showed normal coronary arteries. During his hospital stay, a sudden increase in blood pressure allowed us to suspect a pheochromocytoma, which was confirmed by elevated levels of catecholamines and by the finding of a right adrenal mass on magnetic resonance imaging. The tumor was successfully excised and the patient is now asymptomatic. This case illustrates that pheochromocytoma can present as a mimic of ACS but this is often difficult to diagnose at first glance and often misleads clinicians into making an incorrect diagnosis. In addition, clinicians should be familiar with clinical manifestations of pheochromocytoma, which can help raise clinical suspicion and facilitate the early diagnosis and treatment of pheochromocytoma.

3.
Virol Sin ; 2022 May 02.
Artigo em Inglês | MEDLINE | ID: mdl-35513275

RESUMO

Klebsiella pneumoniae is one of the major pathogens causing global multidrug-resistant infections. Therefore, strategies for preventing and controlling the infections are urgently needed. Phage depolymerase, often found in the tail fiber protein or the tail spike protein, is reported to have antibiofilm activity. In this study, phage P560 isolated from sewage showed specific for capsule locus type KL47 K. pneumoniae, and the enlarged haloes around plaques indicated that P560 encoded a depolymerase. The capsule depolymerase, ORF43, named P560dep, derived from phage P560 was expressed, purified, characterized and evaluated for enzymatic activity as well as specificity. We reported that the capsule depolymerase P560dep, can digest the capsule polysaccharides on the surface of KL47 type K. pneumoniae, and the depolymerization spectrum of P560dep matched to the host range of phage P560, KL47 K. pneumoniae. Crystal violet staining assay showed that P560dep was able to significantly inhibit biofilm formation. Further, a single dose (50 µg/mouse) of depolymerase intraperitoneal injection protected 90%-100% of mice from lethal challenge before or after infection by KL47 carbapenem-resistant K. pneumoniae. And pathological changes were alleviated in lung and liver of mice infected by KL47 type K. pneumoniae. It is demonstrated that depolymerase P560dep as an attractive antivirulence agent represents a promising tool for antimicrobial therapy.

4.
Funct Plant Biol ; 2022 May 02.
Artigo em Inglês | MEDLINE | ID: mdl-35491402

RESUMO

Starch is a major component of the endosperm, directly determining grain yield and quality. Although the key enzymes of starch synthesis have been identified and characterised, the regulatory mechanisms remain unclear. In this study, we identified the novel maize STARCH SYNTHESIS REGULATING PROTEIN1 (ZmSSRP1), which encodes a typical carbohydrate-binding module 48 (CBM48) protein. Expression analysis revealed that ZmSSRP1 was highly expressed in the maize endosperm, while transient expression in maize leaf protoplasts showed localisation in the plastids, dependent on the N-terminal transit peptide. In addition, overexpression of ZmSSRP1 in rice resulted in a decrease in grain thickness and the 1000-grain weight, as well as affecting the starch content and structure of the rice endosperm. The physicochemical properties of starch in the rice endosperm were also altered compared with the wild-type seeds. Real-time quantitative reverse transcription polymerase chain reaction (qRT-PCR) was subsequently performed to determine the expression of starch synthesis-related genes, revealing upregulation of mRNA expression of most genes in the transgenic compared with wild-type lines. Collectively, these findings suggest that ZmSSRP1 acts as a potential regulator of starch synthesis, providing new insight for molecular breeding of high-yielding high-quality maize.

5.
Artigo em Inglês | MEDLINE | ID: mdl-35499701

RESUMO

A highly enantioselective tandem Pudovik addition/[1,2]-phospha-Brook rearrangement of α-alkynylketoamides with diarylphosphine oxides was achieved with a N,N   '-dioxide/Sc III complex as the catalyst. This protocol features broad substrate scope, high regio- and enantioselectivity, and good functional-group compatibility, providing a straightforward route to various trisubstituted allenes with a diarylphosphinate functionality in good yields with high enantioselectivities (up to 97% yield, 96% ee ). Control experiments and theoretical calculations revealed that a synergistic effect of the counterion and water was critical for the regio- and enantioselective protonation after [1,2]-phospha-Brook rearrangement. The synthetic utility of this methodology was demonstrated by the conversion of products into complex bridged polycyclic architectures through intramolecular dearomatizing arene/allene cycloaddition.

7.
Clin Cosmet Investig Dermatol ; 15: 763-781, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35510223

RESUMO

Purpose: To study the efficacy of Ba Zhen Tang in delaying skin photoaging and its potential mechanism based on network pharmacology and molecular docking. Methods: First, we screened the active components and targets of Ba Zhen Tang by Traditional Chinese Medicine Database and Analysis Platform (TCMSP) and The Universal Protein Resource (UniProt). The target genes of skin photoaging were obtained from GeneCards and GeneMap database. Then, we analyzed the protein-protein interaction (PPI) by STRING database. The network map was constructed by Cytoscape. Finally, we performed Gene Ontology (GO) enrichment analysis and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis by Metascape database. The molecular docking via Autodock Vina and Pymol. Furthermore, skin photoaging cellular models were established, and the effects of Ba Zhen Tang on ameliorating skin photoaging were investigated. Results: A total of 160 active ingredients in Ba Zhen Tang and 60 targets of Ba Zhen Tang for delaying skin photoaging were identified. By GO enrichment analysis, 1153 biological process entries, 45 cellular component entries and 89 molecular functional entries were obtained. A total of 155 signal pathways were obtained by KEGG analysis. Ba Zhen Tang is related to MAPK signaling pathway, TNF signaling pathway and AGE-RAGE signaling pathway in diabetic complications, etc., which directly affect the key nodes of photoaging. The molecular docking results showed that there was a certain affinity between the main compounds (kaempferol, quercetin, ß-sitosterol, naringenin) and core target genes (PTGS2, CASP3, MAPK1, MAPK3, TP53). Ba Zhen Tang-treated mouse serum inhibited the senescence and p16INK4a expression of human immortalized keratinocyte (HaCaT) cells irradiated by ultraviolet-B (UVB). Conclusion: Our study elucidated the potential pharmacological mechanism of Ba Zhen Tang in the treatment of photoaging through multiple targets and pathways. The therapeutic effects of Ba Zhen Tang on skin photoaging were validated in cellular models.

8.
Artigo em Inglês | MEDLINE | ID: mdl-35561154

RESUMO

Metal-covalent organic frameworks (MCOFs) have been recently received wide attentions owing to homogeneous distribution of active metal centers that are beneficial for enhancing the application potentials. However, metal complex based functional building blocks for MCOFs synthesis are limited. Herein, two new MCOFs (Ni-Py-COF and Ni-Bn-COF) were constructed via a novel nickel glyoximate based building block. Splendid photocatalytic activity on hydrogen evolution from water and excellent long-term recyclability were achieved using these cost-effective nickel glyoximate based MCOFs as photocatalysts. Excitingly, even without the addition of Pt co-catalyst, the HER of Ni-Py-COF reached up to 626 µmol g -1 h -1 , which is better than many porous organic polymers. This work not only expands the type of building units for MCOFs, but also provides meaningful insights for developing stable, efficient and earth-abundant photocatalysts toward H 2 generation.

9.
Mol Med Rep ; 26(1)2022 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-35552758

RESUMO

Metformin (MET) can effectively treat endometrial hyperplasia (EH), and the expression of glucose transporter type 4 insulin­responsive (GLUT4) is closely associated with the development of EH. The present study aimed to verify the effect of MET in functional EH and polycystic ovary syndrome (PCOS). H&E staining was performed to analyze the severity of EH, and immunohistochemistry was performed to evaluate the expression of GLUT4 in the endometrium of PCOS rats. Reverse transcription­quantitative PCR was used to calculate the expression of long non­coding (lnc)RNA­maternally expressed gene 3 (MEG3), lncRNA­small nucleolar RNA host gene 20 (SNHG20), GLUT4 mRNA, microRNA (miR)­223 and miR­4486. Sequence analysis and luciferase assays were performed to explore the regulatory relationship among certain lncRNAs, miRNAs and target genes. EH in PCOS rats was efficiently inhibited by MET administration. The increased expression of GLUT4 in PCOS rats was attenuated by MET treatment. Moreover, the expression levels of lncRNA­MEG3 and lncRNA­SNHG20 were significantly inhibited in the endometrium of PCOS rats. MET treatment also showed remarkable efficiency in restoring the expression of lncRNA­MEG3 and lncRNA­SNHG20. Meanwhile, the expression levels of miR­223 and miR­4486 were notably elevated in the endometrium of PCOS rats, while MET treatment reduced the expression of miR­223 and miR­4486 in PCOS rats. Furthermore, a luciferase assay confirmed the inhibitory relationship between miR­223 and lncRNA­MEG3/GLUT4 expression, as well as between miR­4486 and lncRNA­SNHG20/GLUT4 expression. GLUT4 knockdown restored the decreased viability of HCC­94 cells induced by overexpression of lncRNA­MEG3. To conclude, MET exhibited a therapeutic effect in the treatment of EH by modulating the lncRNA­MEG3/miR­223/GLUT4 and lncRNA­SNHG20/miR­4486/GLUT4 signaling pathways. This work provides mechanistic insight into the development of EH.

10.
Eur J Med Res ; 27(1): 68, 2022 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-35570320

RESUMO

BACKGROUND: Dermatomyositis is a rare idiopathic inflammatory disease with diverse presentations that can have varying degrees of cutaneous and systemic involvement. This phenotypic heterogeneity makes DM a therapeutic challenge. Some therapeutic drugs, such as hormones and immunosuppressants, have poor therapeutic effects. In recent years, tofacitinib has been reported to be effective in the treatment of dermatomyositis. CASE PRESENTATION: We report a case of anti-MDA5 antibody-positive dermatomyositis that was relieved after treatment with tofacitinib, during which gallbladder gangrene and suppurative cholecystitis occurred. After cholecystectomy, we continued to use tofacitinib and achieved a good therapeutic effect. CONCLUSIONS: Tofacitinib is effective in the treatment of anti-MDA5 antibody-positive dermatomyositis, but the risk of infection is increased. It can still be used after infection control. Close follow-up should be performed during the use of tofacitinib.

11.
Exp Cell Res ; 417(1): 113194, 2022 May 04.
Artigo em Inglês | MEDLINE | ID: mdl-35523305

RESUMO

Breast cancer (BC) is the second cause of cancer-related mortality in women. Seizure related 6 homolog like 2 (SEZ6L2), a protein presented on cell surface, is involved in tumor development. It was found to be highly expressed in BC, however, its role in BC remains unclear. Herein, we aimed to explore the role of SEZ6L2 in BC. Firstly, the correlationship between SEZ6L2 expression and the clinic pathological characteristics of patients diagnosed with BC was analyzed. Subsequently, the role of SEZ6L2 was further explored using MTT, transwell invasion, flow cytometry, colony formation and wound healing assays. The result showed that the level of SEZ6L2 was remarkably correlated with the TNM stage, HER-2 status and lymph node metastasis of BC. Knockdown of SEZ6L2 significantly suppressed the proliferation of BC cells and induced cell cycle arrest at G1 phase. In addition, SEZ6L2 knockdown repressed their migration and invasion. On the contrary, SEZ6L2 overexpression performed the opposite effects. Furthermore, SEZ6L2 also accelerated the in vivo tumorigenesis of BC cells. Additionally, according to bioinformatics resources, we identified upstream transcription factor 1 (USF1) as a transcriptional factor which bound to the promoter of SEZ6L2 and positively regulated its transcription. In conclusion, this study demonstrated that SEZ6L2 was transcriptionally regulated by USF1 and was involved in the growth and metastasis of BC cells. Revealing the role of SEZ6L2 in BC provides additional knowledge for the pathogenesis of BC, which may benefit to BC therapy.

12.
Artigo em Inglês | MEDLINE | ID: mdl-35556142

RESUMO

The most abundant products of the interaction between radiation and matter are low-energy electrons, and the collisions between these electrons and biomolecules are the main initial source of radiation-based biological damage. To facilitate the rapid and accurate quantification of low-energy electrons (0.1-10 keV) in liquid water at different site diameters (1-2000 nm), this study obtained ${\overline{y}}_{\mathrm{F}}$ and ${\overline{y}}_{\mathrm{D}}$data for low-energy electrons under these conditions. This paper proposes a back-propagation (BP) neural network optimized by the mind evolutionary algorithm (MEA) to construct a prediction model and evaluate the corresponding prediction effect. The results show that the ${\overline{y}}_{\mathrm{F}}$ and ${\overline{y}}_{\mathrm{D}}$ values predicted by the MEA-BP neural network algorithm reach a training precision on the order of ${10}^{-8}$. The relative error range between the prediction results of the validated model and the Monte Carlo calculation results is 0.03-5.98% (the error range for single-energy electrons is 0.1-5.98%, and that for spectral distribution electrons is 0.03-4.4%).

13.
Ann Transl Med ; 10(7): 424, 2022 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-35530956

RESUMO

Background: Triple-negative breast cancer (TNBC) is a subtype of breast cancer that is defined clinically by the absence of estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor-2 (Her-2) expression. Due to its unresponsiveness to endocrine or targeted therapies, the clinical prognosis of TNBC is very poor. In recent years, research into immune checkpoint inhibitors (ICIs) has led to significant progress in the treatment of TNBC. A large amount of immune-related adverse events (irAEs), including skin, gastrointestinal, pulmonary, hepatic, cardiovascular, renal and endocrine adverse events, occur in clinical application owing to the widespread use of programmed death-1 (PD-1) inhibitors, although it is rarer to experience two irAEs simultaneously. The simultaneous occurrence of two irAEs increases the difficulty of diagnosis and treatment. Case Description: In this case report, a 51-year-old TNBC woman with a background of modified radical mastectomy 3 years ago was diagnosed with axillary lymph node metastasis. This postoperative recurrent TNBC patient received chemotherapy combined with PD-1 inhibitors, resulting in severe immune-related hepatitis and myocarditis. The patient resolved after treatment with methylprednisolone, interruption of chemotherapy, and discontinuation of immunotherapy. The dosage of methylprednisolone gradually reduced from 80 to 4 mg/day with the improvement of liver function and cardiac function. She completed chemotherapy after recovering from irAEs and followed up for stable disease (SD) until 1st March 2021. Conclusions: With the widespread use of ICIs, the incidence of irAEs has also increased. Early detection and treatment of irAEs presents a new challenge to clinicians. It is the first case report about two severe irAEs in postoperative recurrent TNBC patient after received chemotherapy combined with PD-1 inhibitors. This case illustrates the severe toxicity caused by ICIs which suggests more attention should be paid to early prevention, early diagnosis, and appropriate management of irAEs. Multidisciplinary discussions should be undertaken to improve patient prognosis.

14.
Comput Biol Med ; 146: 105536, 2022 May 06.
Artigo em Inglês | MEDLINE | ID: mdl-35561592

RESUMO

Multiobjective optimization assumes a one-to-one mapping between decisions and objective space, however, this is not always the case. When many variables have the same or equivalent objective value, a multimodal multiobjective issue develops in which more than one Pareto Set (PS) maps to the same Pareto Front (PF). Evolutionary computing research into multimodal multiobjective optimization issues has increased (MMOPs). This paper proposed an enhanced multimodal multiobjective genetic algorithm to crack MMOPs using a special crowding distance calculation (ESNSGA-II). This special crowding distance calculation can consider the diversity of the decision space while paying attention to the diversity of the object space. Then, a unique crossover mechanism is established by combining the simulated binary crossover (SBX) method with the capacity of Pareto solutions to generate offspring solutions. The balance between convergence and diversity in both decision space and object space can be guaranteed synchronously, and PS distribution and PF accuracy may both be enhanced. The proposed ESNSGA-II uses the CEC2020 benchmarks MMF1-MMF8 to assess its properties. Comparing the ESNSGA-II to other recently established multimodal multiobjective evolutionary techniques demonstrates that it is capable of efficiently searching numerous PSs of MMOPs. Finally, the suggested ESNSGA-II is used to address a real MMOP problem of pulmonary hypertension detection via arterial blood gas analysis. The statistical analysis reveals that the suggested ESNSGA-II algorithm outperforms other algorithms on this MMOP, and so may be considered a possible tool for pulmonary hypertension.

15.
Int J Mol Sci ; 23(9)2022 May 07.
Artigo em Inglês | MEDLINE | ID: mdl-35563630

RESUMO

Recently, the extensive research of efficient bifunctional electrocatalysts (oxygen evolution reaction (OER) and hydrogen evolution reaction (HER)) on water splitting has drawn increasing attention. Herein, a salt-template strategy is prepared to synthesize nitrogen-doped carbon nanosheets encapsulated with dispersed CoSe2 nanoparticles (CoSe2-NC NSs), while the thickness of CoSe2-NC NSs is only about 3.6 nm. Profiting from the ultrathin morphology, large surface area, and promising electrical conductivity, the CoSe2-NC NSs exhibited excellent electrocatalytic of 10 mA·cm-2 current density at small overpotentials of 247 mV for OER and 75 mV for HER. Not only does the nitrogen-doped carbon matrix effectively avoid self-aggregation of CoSe2 nanoparticles, but it also prevents the corrosion of CoSe2 from electrolytes and shows favorable durability after long-term stability tests. Furthermore, an overall water-splitting system delivers a current density of 10 mA·cm-2 at a voltage of 1.54 V with resultants being both the cathode and anode catalyst in alkaline solutions. This work provides a new way to synthesize efficient and nonprecious bifunctional electrocatalysts for water splitting.

16.
Food Chem ; 390: 133115, 2022 Apr 29.
Artigo em Inglês | MEDLINE | ID: mdl-35567970

RESUMO

The changes in the structure and oil absorption characteristics of three different crystalline starches under different initial moisture levels (20-50%) during frying were investigated. The granule morphology of potato starch was more severely disrupted during frying, especially under 40% moisture or higher. At 50% moisture, the crystallinity of potato starch decreased by 29.7% and the R1 value decreased by 0.17. The effect of frying treatment on the structural properties of wheat starch and pea bean starch was less than that of potato starch. At 30% moisture, the ΔH values for wheat starch, potato starch, and pea bean starch were 7.8, 5.5, and 8.1 J/g respectively. The above results showed that B-type potato starch was more susceptible to the effects during frying than A-type wheat and C-type pea bean starch, which led to more oil absorption of B-type potato starch than A-type wheat or C-type pea bean starch.

17.
Hum Vaccin Immunother ; : 1-19, 2022 May 02.
Artigo em Inglês | MEDLINE | ID: mdl-35499517

RESUMO

There is a wealth of data suggesting that the effectiveness of existing vaccines against the Omicron variant, the most mutated SARS-CoV-2 variant to date, has been substantially reduced if only primary vaccination is administered. Therefore, the effectiveness of booster vaccination against the Omicron variant has become a topic of current interest. We conducted a comprehensive search in PubMed, Embase, and the Cochrane Library to collect various pseudovirus neutralization tests or live virus neutralization tests for the Omicron variant, with serum specimens from booster vaccinees. We extracted neutralization titers for the Omicron variant, the original strain, and the other variants before and after booster vaccination, and then manually calculated the fold increase or decrease in neutralization titers for the Omicron variant relative to the other variants, and the fold increase in neutralization titers for the Omicron variant after booster vaccination compared with that before booster vaccination. In the two-dose vaccination regimen, the neutralization titers against the Omicron variant decreased substantially compared to the original strain and other variants. However, after booster vaccination, both homologous and heterologous booster vaccination, the neutralization of serum antibodies against the Omicron variant was significantly improved, although still lower than that of the original strain and other variants. The booster vaccination program based on existing vaccines can produce broad but incomplete immunity against the Omicron variant.

19.
J Phys Chem A ; 2022 May 10.
Artigo em Inglês | MEDLINE | ID: mdl-35536543

RESUMO

Methyl butyl ketone (MBK, 2-hexanone) is a common atmospheric oxygenated volatile organic compound (OVOC) owing to broad industrial applications, but its atmospheric oxidation mechanism remains poorly understood. Herein, the detailed mechanisms and kinetic properties of MBK oxidation initiated by OH radicals and subsequent transformation of the resulting intermediates are performed by employing quantum chemical and kinetic modeling methods. The calculations show that H-abstraction at the C4 position of MBK is more favorable than those at the other positions, with the total rate coefficient of k(T) = 4.13 × 10-14 exp(1576/T) cm3 molecule-1 s-1 at 273-400 K. The dominant pathway of unimolecular degradation of the C-centered alkyl radical is 1,2-acyl group migration. For the isomerization of the peroxy radical RO2, 1,5- and 1,6-H shifts are more favorable than 1,3- and 1,4-H shifts. The multiconformer rate coefficient kMC-TST of the first H-shift of the RO2 radical is estimated to be 1.40 × 10-3 s-1 at room temperature. Compared to the H-shifts of analogous aliphatic RO2 radicals, it can be concluded that the carbonyl group enhances the H-shift rates by as much as 2-4 orders of magnitude. The rate coefficients of the RO2 radical reaction with the HO2 radical exhibit a weakly negative temperature dependence, and the pseudo-first-order rate constant k'HO2 = kHO2[HO2] is calculated to be 3.32-22.10 × 10-3 s-1 at ambient temperature. The bimolecular reaction of the RO2 radical with NO leads to the formation of 3-oxo-butanal as the main product with the formation concentration of 2.2-7.4 µg/m3 in urban areas. The predicted pseudo-first-order rate constant k'NO = kNO[NO] is 2.20-9.98 s-1 at room temperature. By comparing the kMC-TST, k'HO2, and k'NO, it can be concluded that reaction with NO is the dominant removal pathway for the RO2 radical formed from the OH-initiated oxidation of MBK. These findings are expected to deepen our understanding of the photochemical oxidation of ketones under realistic atmospheric conditions.

20.
Water Res ; 216: 118351, 2022 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-35390703

RESUMO

Nitrate (NO3-) is a ubiquitous contaminant in water and wastewater. Conventional treatment processes such as adsorption and membrane separation suffer from low selectivity for NO3- removal, causing high energy consumption and adsorbents usage. In this study, we demonstrate selective removal of NO3- in an electrosorption process by a thin, porous carbonized eggshell membrane (CESM) derived from eggshell bio-waste. The CESM possesses an interconnected hierarchical pore structure with pore size ranging from a few nanometers to tens of micrometers. When utilized as the anode in an electrosorption process, the CESM exhibited strong selectivity for NO3- over Cl-, SO42-, and H2PO4-. Adsorption of NO3- by the CESM reached 2.4 × 10-3 mmol/m2, almost two orders of magnitude higher than that by activated carbon (AC). More importantly, the CESM achieved NO3-/Cl- selectivity of 7.79 at an applied voltage of 1.2 V, the highest NO3-/Cl- selectivity reported to date. The high selectivity led to a five-fold reduction in energy consumption for NO3- removal compared to electrosorption using conventional AC electrodes. Density function theory calculation suggests that the high NO3- selectivity of CESM is attributed to its rich nitrogen-containing functional groups, which possess higher binding energy with NO3- compared to Cl-, SO42-, and H2PO4-. These results suggest that nitrogen-rich biomaterials are good precursors for NO3- selective electrodes; similar chemistry can also be used in other materials to achieve NO3- selectivity.


Assuntos
Nitratos , Purificação da Água , Animais , Carvão Vegetal , Casca de Ovo , Eletrodos , Nitratos/química , Nitrogênio , Óxidos de Nitrogênio , Porosidade , Águas Residuárias , Água , Purificação da Água/métodos
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