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1.
J Biol Chem ; 300(6): 107343, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38705395

RESUMO

Rieske nonheme iron aromatic ring-hydroxylating oxygenases (RHOs) play pivotal roles in determining the substrate preferences of polycyclic aromatic hydrocarbon (PAH) degraders. However, their potential to degrade high molecular weight PAHs (HMW-PAHs) has been relatively unexplored. NarA2B2 is an RHO derived from a thermophilic Hydrogenibacillus sp. strain N12. In this study, we have identified four "hotspot" residues (V236, Y300, W316, and L375) that may hinder the catalytic capacity of NarA2B2 when it comes to HMW-PAHs. By employing structure-guided rational enzyme engineering, we successfully modified NarA2B2, resulting in NarA2B2 variants capable of catalyzing the degradation of six different types of HMW-PAHs, including pyrene, fluoranthene, chrysene, benzo[a]anthracene, benzo[b]fluoranthene, and benzo[a]pyrene. Three representative variants, NarA2B2W316I, NarA2B2Y300F-W316I, and NarA2B2V236A-W316I-L375F, not only maintain their abilities to degrade low-molecular-weight PAHs (LMW-PAHs) but also exhibited 2 to 4 times higher degradation efficiency for HMW-PAHs in comparison to another isozyme, NarAaAb. Computational analysis of the NarA2B2 variants predicts that these modifications alter the size and hydrophobicity of the active site pocket making it more suitable for HMW-PAHs. These findings provide a comprehensive understanding of the relationship between three-dimensional structure and functionality, thereby opening up possibilities for designing improved RHOs that can be more effectively used in the bioremediation of PAHs.


Assuntos
Hidrocarbonetos Policíclicos Aromáticos , Hidrocarbonetos Policíclicos Aromáticos/metabolismo , Hidrocarbonetos Policíclicos Aromáticos/química , Peso Molecular , Proteínas de Bactérias/metabolismo , Proteínas de Bactérias/química , Proteínas de Bactérias/genética , Especificidade por Substrato , Biodegradação Ambiental , Oxigenases/metabolismo , Oxigenases/química , Oxigenases/genética , Hidroxilação
2.
Small ; 20(14): e2306983, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-37988639

RESUMO

Constructing S-scheme heterojunction catalysts is a key challenge in visible-light catalysed degradation of organic pollutants. Most heterojunction materials are reported to face significant obstacles in the separation of photogenerated electron-hole pairs owing to differences in the material size and energy barriers. In this study, sulfur-doped g-C3N4 oxidative-type semiconductor materials are synthesized and then coupled with BiOBr reductive-type semiconductor to form S-g-C3N4/BiOBr S-scheme heterojunction. A strong and efficient internal electric field is established between the two materials, facilitating the separation of photogenerated electron-hole pairs. Notably, in situ XPS proved that after visible light irradiation, Bi3+ is converted into Bi(3+ɑ)+, and a large number of photogenerated holes are produced on the surface of BiOBr, which oxidized and activated H2O into •OH.  â€¢OH cooperated with •O2 - and 1O2 to attack Rhodamine B (RhB) molecules to achieve deep oxidation mineralization. The composite material is designed with a LUMO energy level higher than that of RhB, promoting the sensitization of RhB by injecting photogenerated electrons into the heterojunction, thereby enhancing the photocatalytic performance to 22.44 times that of pure g-C3N4. This study provides a new perspective on the efficient degradation of organic molecules using visible light catalysis.

3.
J Magn Reson Imaging ; 2024 Jan 18.
Artigo em Inglês | MEDLINE | ID: mdl-38235948

RESUMO

BACKGROUND: The hemodynamics of the cerebral sinuses play a vital role in understanding blood flow-related diseases, yet the hemodynamics of the cerebral sinuses in normal adults remains an unresolved issue. PURPOSE: To evaluate hemodynamics in the cerebral sinus of adults using 4-dimensional flow MRI (4D Flow MRI). STUDY TYPE: Cross-sectional. POPULATION: Ninety-nine healthy volunteers (mean age, 42.88 ± 13.16 years old; females/males, 55/44). FIELD STRENGTH/SEQUENCE: 3 T/4D Flow MRI. ASSESSMENT: The blood flow velocity, average blood flow rate (Q), and vortexes at the superior sagittal sinus (SSS), straight sinus (STS), transverse sinus, sigmoid sinus, and jugular bulb of each volunteer were evaluated by two independent neuroradiologists. The relationship between the total cerebral Q and sex and age was also assessed. Twelve volunteers underwent two scans within a month. STATISTICAL TESTS: The intraclass correlation coefficient (ICC) evaluated the inter-observer agreement. Blood flow parameters among volunteers were compared by the independent-sample t-test or Mann-Whitney U test. The multiple linear regression equation was used to evaluate the relationship between total cerebral Q and age and sex. P < 0.05 indicated statistical significance. RESULTS: The test-retest and interobserver reliability of average velocity and Q were moderate to high (ICC: 0.54-0.99). Cerebral sinus velocity varied by segment and cardiac cycle. The SSS's velocity and Q increased downstream and Q near torcular herophili was 3.5 times that through the STS. The total cerebral Q decreased by 0.06 mL/s per year (ß = -0.06 ± 0.013) and was sex-independent within the group. Vortexes were found in 12.12%, 8.9%, and 59.8% of torcular herophili, transverse-sigmoid junction, and jugular bulb, respectively, and were related to higher upstream flow. DATA CONCLUSION: Cerebral sinuses could be measured visually and quantitatively in vivo by 4D Flow MRI, providing a basis for future research on pulsating tinnitus, multiple sclerosis, and other related diseases. EVIDENCE LEVEL: 2 TECHNICAL EFFICACY: Stage 1.

4.
BMC Vet Res ; 20(1): 125, 2024 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-38561794

RESUMO

BACKGROUND: Resolvin D1 (RvD1), a specialized pro-resolving lipid mediator (SPM), is derived from docosahexaenoic acid (DHA). It plays a key role in actively resolving inflammatory responses, which further reduces small intestinal damage. However, its regulation of the apoptosis triggered by endoplasmic reticulum (ER) stress in intestinal epithelial cells is still poorly understood. The intestinal porcine epithelial cells (IPEC-J2) were stimulated with tunicamycin to screen an optimal stimulation time and concentration to establish an ER stress model. Meanwhile, RvD1 (0, 1, 10, 20, and 50 nM) cytotoxicity and its impact on cell viability and the effective concentration for reducing ER stress and apoptosis were determined. Finally, the effects of RvD1 on ER stress and associated apoptosis were furtherly explored by flow cytometry analysis, AO/EB staining, RT-qPCR, and western blotting. RESULTS: The ER stress model of IPEC-J2 cells was successfully built by stimulating the cells with 1 µg/mL tunicamycin for 9 h. Certainly, the increased apoptosis and cell viability inhibition also appeared under the ER stress condition. RvD1 had no cytotoxicity, and its concentration of 1 nM significantly decreased cell viability inhibition (p= 0.0154) and the total apoptosis rate of the cells from 14.13 to 10.00% (p= 0.0000). RvD1 at the concentration of 1 nM also significantly reduced the expression of glucose-regulated protein 78 (GRP-78, an ER stress marker gene) (p= 0.0000) and pro-apoptotic gene Caspase-3 (p= 0.0368) and promoted the expression of B cell lymphoma 2 (Bcl-2, an anti-apoptotic gene)(p= 0.0008). CONCLUSIONS: Collectively, the results shed light on the potential of RvD1 for alleviating apoptosis triggered by ER stress, which may indicate an essential role of RvD1 in maintaining intestinal health and homeostasis.


Assuntos
Apoptose , Ácidos Docosa-Hexaenoicos , Animais , Suínos , Ácidos Docosa-Hexaenoicos/farmacologia , Tunicamicina/farmacologia , Estresse do Retículo Endoplasmático
5.
Brain Inj ; : 1-3, 2024 May 09.
Artigo em Inglês | MEDLINE | ID: mdl-38722041

RESUMO

BACKGROUND: Cerebral fat embolism (CFE) is a rare but potentially fatal complication that can occur after long bone fractures. It represents one subcategory of fat embolisms (FE). Diagnosing CFE can be challenging due to its variable and nonspecific clinical manifestations. We report a case of CFE initially presenting with turbid urine, highlighting an often neglected sign. CASE PRESENTATION: A 69-year-old male was admitted after a traffic accident resulting in bilateral femoral fractures. Sixteen hours post-admission, grossly turbid urine was noted but received no special attention. Four hours later, he developed rapid deterioration of consciousness and respiratory distress. Neurological examination revealed increased upper limb muscle tone and absent voluntary movements of lower limbs. Brain MRI demonstrated a 'starfield pattern' of diffuse punctate lesions, pathognomonic for CFE. Urine microscopy confirmed abundant fat droplets. Supportive treatment and fracture fixation were performed. The patient regained consciousness after 3 months but had residual dysphasia and limb dyskinesia. CONCLUSION: CFE can present with isolated lipiduria preceding overt neurological or respiratory manifestations. Heightened awareness of this subtle sign in high-risk patients is crucial for early diagnosis and intervention. Prompt urine screening and neuroimaging should be considered when gross lipiduria occurs after long bone fractures.

6.
J Am Chem Soc ; 145(24): 13400-13410, 2023 Jun 21.
Artigo em Inglês | MEDLINE | ID: mdl-37294213

RESUMO

Heterogeneous bimetallic nanocrystals featuring explicit spatial configurations and abundant twin defects can simultaneously enable geometric and ligand effects to enhance catalytic and photonic applications. Herein, we report two growth patterns of Au atoms on penta-twinned Pd decahedra, involving twin proliferation to generate asymmetric Pd-Au Janus icosahedra and twin elongation to produce anisotropic Pd@Au core-shell starfishes, respectively. Mechanistic analysis indicates that the injection rate determines the lower-limit number (nlow) of Au(III) ions in the steady state and thus controls the growth pattern. When nlow ≤ 5.5, the kinetic rate is slow enough to initiate asymmetrical one-side growth but fast enough to outpace surface diffusion; Au tetrahedral subunits are successively proliferated along the axial ⟨110⟩ direction of Pd decahedra to form Pd-Au Janus icosahedra. Composed of five Pd and 15 Au tetrahedral subunits, such a heterogeneous icosahedron supports high (2.2 GPa) tensile strain and high strain difference up to +21.9%. In contrast, when nlow > 5.5, the fast reduction kinetics promotes symmetric growth with inadequate surface diffusion. As such, Au atoms are laterally deposited along five high-indexed ⟨211⟩ ridges of Pd decahedra to generate concave Pd@Au core-shell starfishes with tunable sizes (28-40 nm), twin elongation ratios (33.82-162.08%), and lattice expansion ratios (8.82-20.10%).

7.
Appl Environ Microbiol ; 89(10): e0086523, 2023 10 31.
Artigo em Inglês | MEDLINE | ID: mdl-37819076

RESUMO

Polycyclic aromatic hydrocarbons (PAHs) are harmful to human health due to their carcinogenic, teratogenic, and mutagenic effects. A thermophilic Hydrogenibacillus sp. strain N12 capable of degrading a variety of PAHs and derivatives was previously isolated. In this study, an aromatic ring-hydroxylating oxygenase, NarA2B2, was identified from strain N12, with substrate specificity including naphthalene, phenanthrene, dibenzothiophene, fluorene, acenaphthene, carbazole, biphenyl, and pyrene. NarA2B2 was proposed to add one or two atoms of molecular oxygen to the substrate and catalyze biphenyl at C-2, 2 or C-3, 4 positions with different characteristics than before. The key catalytic amino acids, H222, H227, and D379, were identified as playing a pivotal role in the formation of the 2-his-1-carboxylate facial triad. Furthermore, we conducted molecular docking and molecular dynamics simulations, notably, D219 enhanced the stability of the iron center by forming two stable hydrogen bonds with H222, while the mutation of F216, T223, and H302 modulated the catalytic activity by altering the pocket's size and shape. Compared to the wild-type (WT) enzyme, the degradation ratios of acenaphthene by F216A, T223A, and H302A had an improvement of 23.08%, 26.87%, and 29.52%, the degradation ratios of naphthalene by T223A and H302A had an improvement of 51.30% and 65.17%, while the degradation ratio of biphenyl by V236A had an improvement of 77.94%. The purified NarA2B2 was oxygen-sensitive when it was incubated with L-ascorbic acid in an anaerobic environment, and its catalytic activity was restored in vitro. These results contribute to a better understanding of the molecular mechanism responsible for PAHs' degradation in thermophilic microorganisms.IMPORTANCE(i) A novel aromatic ring-hydroxylating oxygenase named NarA2B2, capable of degrading multiple polycyclic aromatic hydrocarbons and derivatives, was identified from the thermophilic microorganism Hydrogenibacillus sp. N12. (ii) The degradation characteristics of NarA2B2 were characterized by adding one or two atoms of molecular oxygen to the substrate. Unlike the previous study, NarA2B2 catalyzed biphenyl at C-2, 2 or C-3, 4 positions. (iii) Catalytic sites of NarA2B2 were conserved, and key amino acids F216, D219, H222, T223, H227, V236, F243, Y300, H302, W316, F369, and D379 played pivotal roles in catalysis, as confirmed by protein structure prediction, molecular docking, molecular dynamics simulations, and point mutation.


Assuntos
Oxigenases , Hidrocarbonetos Policíclicos Aromáticos , Humanos , Oxigenases/metabolismo , Acenaftenos , Simulação de Acoplamento Molecular , Hidrocarbonetos Policíclicos Aromáticos/metabolismo , Aminoácidos , Oxigênio , Biodegradação Ambiental
8.
Chemistry ; 29(32): e202300398, 2023 Jun 07.
Artigo em Inglês | MEDLINE | ID: mdl-37042548

RESUMO

Concave nanostructure with highly branched architecture and abundant step atoms is one kind of desirable materials for energy conversion devices. However, current synthetic strategies for non-noble metal-based NiCoP concave nanostructure still remain challenging. Herein, we demonstrate a site-selective chemical etching and subsequent phosphorating strategy to fabricate highly branched NiCoP concave nanocrosses (HB-NiCoP CNCs). The HB-NiCoP CNCs are consisted of six axial arms in three-dimensional space and each protruding arm is equipped with high-density atomic steps, ledges and kinks. As an electrocatalyst towards oxygen evolution reaction, the HB-NiCoP CNCs exhibit remarkably enhanced activity and stability, with small overpotential of 289 mV to reach 10 mA cm-2 , surpassing the NiCoP nanocages and commercial RuO2 . The superior OER performance of HB-NiCoP CNCs is originated from the highly branched concave structure, the synergistic effect between bimetal Ni and Co atoms, as well as the electronic structure modulation from P.


Assuntos
Braço , Níquel , Eletrônica , Oxigênio
9.
Eur Radiol ; 33(6): 4464-4471, 2023 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-36648550

RESUMO

OBJECTIVES: To investigate the imaging features of unilateral pulsatile tinnitus (PT) with jugular bulb wall dehiscence (JBWD). METHODS: Computerized tomography angiography images of unilateral PT patients were reviewed between 2019 and 2021. Thirty-one symptomatic JBWD patients without sigmoid sinus wall dehiscence (SSWD) were included. Thirty-eight patients with SSWD were used as the control group. The prevalence of JBWD was calculated. The area and height of the jugular bulb, the extent of dehiscence, the presence of jugular bulb diverticulum, posterior condylar emissary vein (PCEV), oblique occipital sinus (OOS), venous outflow laterality (VOL), the degree of transverse sinus stenosis (TSS), and the pituitary height to sella turcica ratio were compared between the two groups. RESULTS: The prevalence of JBWD was 12.1%, and JBWD was established as a causative diagnosis in 5.0% of unilateral PT patients. There were no statistical differences in the gender, symptomatic side, or VOL between the two groups. The area of the jugular bulb was larger and the height was higher (parea < 0.001, pheight = 0.005). The prevalence of jugular bulb diverticulum was higher in the JBWD group (p = 0.002). The degree of symptomatic TSS was less severe (p < 0.001), and the prevalence of bilateral TSS was lower in the JBWD group (p < 0.001). The pituitary height to sella turcica ratio was greater (p = 0.004), the prevalence of PCEV (p = 0.014) was lower, and OOS (p = 0.015) was greater in the JBWD group. CONCLUSIONS: The correlating factors of PT with JBWD and PT with SSWD are significantly different. These findings can further facilitate early and efficient PT treatment. KEY POINTS: • The incidence of jugular bulb dehiscence (JBWD) accounted for approximately 12.1% in pulsatile tinnitus (PT) patients, and JBWD was established as a causative diagnosis in 5.0% of PT patients. • PT required large blood flows and abnormal flow patterns, whether in JBWD or sigmoid sinus wall dehiscence groups. • JBWD causing PT has some unique characteristic findings on CT.


Assuntos
Divertículo , Seios Paranasais , Zumbido , Humanos , Zumbido/diagnóstico por imagem , Zumbido/epidemiologia , Cavidades Cranianas/diagnóstico por imagem , Angiografia por Tomografia Computadorizada , Divertículo/complicações , Divertículo/diagnóstico por imagem , Divertículo/epidemiologia , Constrição Patológica , Veias Jugulares/diagnóstico por imagem
10.
J Anim Physiol Anim Nutr (Berl) ; 107(3): 839-849, 2023 May.
Artigo em Inglês | MEDLINE | ID: mdl-36239230

RESUMO

As a potential prebiotic, soybean oligosaccharides (SBOS) can improve animal health by modulating gut microbiota. The aim of this study was to investigate the different effects of supplementing SBOS and supplementing SBOS plus probiotic on the growth and health of pigs. Three groups of growing pigs (n = 12) were fed with basal diet (Control), basal diet + 0.5% SBOS (SBOS), or basal diet +0.5% SBOS + 0.1% compound probiotics (SOP) for 42 days. Results showed that SBOS and SOP treatments had positive effects on the pigs in the experiment, and the latter was more effective. Compared with the control pigs, the average daily gain of SBOS group and SOP group slightly increased, SOP significantly increased the serum levels of growth hormone and thyroid hormone T3. Importantly, serum concentrations of immunoglobulin (IgA, IgG and IgM), total antioxidant capacity and superoxide dismutase in both treatments were increased significantly, SOP group most. Moreover, the faecal odour compounds of pigs, especially skatole, were significantly reduced by the treatments. Additionally, SOP significantly increased the diversity and richness of the faecal microbiota, both the treatments increased genera of norank_f_Muribaculaceae and Ruminococcaceae but reduced Lactobacillus. Correlation analysis indicated that Lactobacillus was significantly positively correlated with odour compounds, while Ruminococcaceae was the opposite. Conclusively, synbiotics combined with SBOS and probiotics had stronger promotion effects on the growth and health of pigs.


Assuntos
Microbioma Gastrointestinal , Lactobacillales , Probióticos , Suínos , Animais , Glycine max , Odorantes , Probióticos/farmacologia , Oligossacarídeos/farmacologia , Dieta/veterinária , Lactobacillus , Ração Animal/análise
11.
BMC Oral Health ; 23(1): 737, 2023 10 09.
Artigo em Inglês | MEDLINE | ID: mdl-37814269

RESUMO

BACKGROUND: Osseous changes of the temporomandibular joint (TMJ) are related to the progression of temporomandibular disorders (TMD), and computed tomography (CT) plays a vital role in disease evaluation. OBJECTIVE: The aims of this study were to evaluate the image quality and diagnostic value of ultra-high-resolution CT (U-HRCT) in TMD compared to cone-beam CT (CBCT). METHODS: TMD patients who underwent both CBCT and U-HRCT between November 2021 and September 2022 were retrospectively included. Image quality scores were assigned for four osseous structures (the cortical and trabecular bones of the condyle, articular eminence, and glenoid fossa) by two independent observers from Score 1 (unacceptable) to Score 5 (excellent). Diagnostic classification of TMD was categorized as follows: Class A (no evident lesion), Class B (indeterminate condition) and Class C (definitive lesion). Image quality scores and diagnostic classifications were compared between CBCT and U-HRCT. The Cohen's Kappa test, Wilcoxon signed-rank test, Chi-square test and Fisher's exact test were conducted for statistical analysis. RESULTS: Thirty TMD patients (median age, 30 years; interquartile range, 26-43 years; 25 females) with 60 TMJs were enrolled. Image quality scores were higher for U-HRCT than for CBCT by both observers (all Ps < 0.001). Definitive diagnoses (Class A and C) were achieved in more cases with U-HRCT than with CBCT (93.3% vs. 65.0%, Fisher's exact value = 7.959, P = 0.012). Among the 21 cases which were ambiguously diagnosed (Class B) by CBCT, definitive diagnosis was achieved for 17 cases (81.0%) using U-HRCT. CONCLUSIONS: U-HRCT can identify osseous changes in TMD, providing improved image quality and a more definitive diagnosis, which makes it a feasible diagnostic imaging method for TMD.


Assuntos
Transtornos da Articulação Temporomandibular , Articulação Temporomandibular , Feminino , Humanos , Adulto , Estudos Retrospectivos , Articulação Temporomandibular/diagnóstico por imagem , Transtornos da Articulação Temporomandibular/diagnóstico por imagem , Transtornos da Articulação Temporomandibular/patologia , Tomografia Computadorizada por Raios X , Côndilo Mandibular/patologia , Tomografia Computadorizada de Feixe Cônico
12.
Angew Chem Int Ed Engl ; 62(44): e202305530, 2023 Oct 26.
Artigo em Inglês | MEDLINE | ID: mdl-37533227

RESUMO

Despite the intriguing potential shown by Sn-based perovskite oxides in CO2 electroreduction (CO2 RR), the rational optimization of their CO2 RR properties is still lacking. Here we report an effective strategy to promote CO2 -to-HCOOH conversion of Sn-based perovskite oxides by A-site-radius-controlled Sn-O bond lengths. For the proof-of-concept examples of Ba1-x Srx SnO3 , as the A-site cation average radii decrease from 1.61 to 1.44 Å, their Sn-O bonds are precisely shortened from 2.06 to 2.02 Å. Our CO2 RR measurements show that the activity and selectivity of these samples for HCOOH production exhibit volcano-type trends with the Sn-O bond lengths. Among these samples, the Ba0.5 Sr0.5 SnO3 features the optimal activity (753.6 mA ⋅ cm-2 ) and selectivity (90.9 %) for HCOOH, better than those of the reported Sn-based oxides. Such optimized CO2 RR properties could be attributed to favorable merits conferred by the precisely controlled Sn-O bond lengths, e.g., the regulated band center, modulated adsorption/activation of intermediates, and reduced energy barrier for *OCHO formation. This work brings a new avenue for rational design of advanced Sn-based perovskite oxides toward CO2 RR.

13.
Curr Issues Mol Biol ; 44(5): 2038-2053, 2022 May 06.
Artigo em Inglês | MEDLINE | ID: mdl-35678667

RESUMO

Skeletal muscle satellite cells (SMSCs), which are multifunctional muscle-derived stem cells, can differentiate into adipocytes. Long-chain non-coding RNA (lncRNA) has diverse biological functions, including the regulation of gene expression, chromosome silencing, and nuclear transport. However, the regulatory roles and mechanism of lncRNA during adipogenic transdifferentiation in muscle cells have not been thoroughly investigated. Here, porcine SMSCs were isolated, cultured, and induced for adipogenic differentiation. The expressions of lncRNA and mRNA at different time points during transdifferentiation were analysed using RNA-seq analysis. In total, 1005 lncRNAs and 7671 mRNAs showed significant changes in expression at differential differentiation stages. Time-series expression analysis showed that the differentially expressed (DE) lncRNAs and mRNAs were clustered into 5 and 11 different profiles with different changes, respectively. GO, KEGG, and REACTOME enrichment analyses revealed that DE mRNAs with increased expressions during the trans-differentiation were mainly enriched in the pathways for lipid metabolism and fat cell differentiation. The genes with decreased expressions were mainly enriched in the regulation of cell cycle and genetic information processing. In addition, 1883 DE mRNAs were regulated by 193 DE lncRNAs, and these genes were related to the controlling in cell cycle mainly. Notably, three genes in the fatty acid binding protein (FABP) family significantly and continuously increased during trans-differentiation, and 15, 13, and 11 lncRNAs may target FABP3, FABP4, and FABP5 genes by cis- or trans-regulation, respectively. In conclusion, these studies identify a set of new potential regulator for adipogenesis and cell fate and help us in better understanding the molecular mechanisms of trans-differentiation.

14.
Environ Microbiol ; 24(1): 436-450, 2022 01.
Artigo em Inglês | MEDLINE | ID: mdl-34897956

RESUMO

Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous pollutants threatening ecosystems and human health. Here, we isolated and characterized a new strain, Hydrogenibacillus sp. N12, which is a thermophilic PAH-degrader. Strain N12 utilizes naphthalene as a sole carbon and energy source above 60°C and co-metabolizes many other PAHs as well. The metabolites were identified in the catabolism of naphthalene by gas chromatography-mass spectrometry (GC-MS) and stable isotopic analysis. Based on the identified metabolites, we proposed two possible metabolic pathways, one via salicylic acid and the other via phthalic acid. Whole-genome sequencing reveals that strain N12 possesses a small chromosome of 2.6 Mb. Combining genetic and transcriptional information, we reveal a new gene cluster for the naphthalene degradation. The genes, designated as narAaAb that are predicted to encode the alpha and beta subunits of naphthalene dioxygenase, were subsequently subcloned into Escherichia coli and the enzyme activity was detected by whole-cell transformation. Capacity to degrade several other tricyclic-PAHs was also characterized, suggesting co-existence of other constitutively expressed enzyme systems in strain N12 in addition to the naphthalene degradation gene cluster. Our study provides insights into the potential of the thermophilic PAH-degrader in biotechnology and environmental management applications.


Assuntos
Poluentes Ambientais , Hidrocarbonetos Policíclicos Aromáticos , Biodegradação Ambiental , Ecossistema , Poluentes Ambientais/metabolismo , Cromatografia Gasosa-Espectrometria de Massas , Humanos , Hidrocarbonetos Policíclicos Aromáticos/metabolismo
15.
Inorg Chem ; 61(28): 10999-11010, 2022 Jul 18.
Artigo em Inglês | MEDLINE | ID: mdl-35794033

RESUMO

BiOClxBr1-x (0 ≤ x ≤ 1) solid solutions were synthesized at room temperature by one-step coprecipitation. Relative proportions of halogens in the anion layer were regulated, and thus, the band gap of BiOClxBr1-x could be adjusted to suitable values to enhance the photocatalytic reaction. BiOClxBr1-x exhibited enhanced visible-light response and higher photocatalytic activity in degrading rhodamine B (RhB) compared with individual BiOCl or BiOBr. Especially, BiOCl0.5Br0.5 showed the highest photocatalytic activity. Comparative tests showed that within 36 min the degradation rates of RhB upon BiOBr, BiOCl, and BiOCl0.5Br0.5 were 55.66, 24.03, and 94.91%, respectively. BiOCl0.5Br0.5 was further decorated with carbon quantum dots (CQDs) to promote the separation of photogenerated charge carriers. The photocatalytic activity was considerably enhanced by moderate doping of CQDs, and the degradation rate of RhB reached nearly 100% within 18 min upon 3CQDs-BiOCl0.5Br0.5 (the loading content of CQDs was 0.42 wt %). Active-species-trapping tests confirmed that h+ is the primary active species for photocatalytic degradation of RhB, whereas •O2- and e- were the secondary ones. The synergistic effects of the band structure adjustment and CQD decoration on the photocatalytic activity were mainly expounded as the enhanced separation of photogenerated charge carriers and optimal redox potentials. In addition, the reuse and service life of the catalysts were analyzed. After five cycles, the photocatalytic activity still remained over 95%.

16.
Inorg Chem ; 61(26): 10211-10219, 2022 Jul 04.
Artigo em Inglês | MEDLINE | ID: mdl-35723430

RESUMO

Pd-based metallenes have attracted great attention recently as newly burgeoning two-dimensional (2D) materials, attributed to their significantly increased active surface areas and intrinsic electrocatalytic activities. Therefore, they could be used as a potential candidate as the high-performance electrocatalyst for methanol oxidation reactions (MORs) in the direct methanol fuel cell. Herein, a new strategy is proposed to fabricate NiCoPd inlaid NiCo-bimetallene (NiCoPd/NiCo-bimetallene) by the structure directing effect of 18-crown-6 ether under an ultrasonic-pulse interface together with the HCHO reduction and atom-diffusion-aging process. NiCoPd ternary-alloys with uniformly dispersed Pd active sites are decorated onto NiCo-bimetallenes, achieving remarkably enhancing the effective utilization of Pd atoms. What is more, the intrinsic activity is enhanced by the "bifunctional mechanism" of NiCo-bimetallene adsorption of intermediate species and increased Pd-active sites. Moreover, the anti-CO poisoning ability is optimized through the "alloying ligand effect" of NiCoPd. Therefore, the NiCoPd/NiCo-bimetallene exhibits excellent mass activity for MOR, which is higher than commercial Pd/C. This work suggests a new way of the Pd-based metallenes catalyst approach to the efficient electrocatalytic MOR.

17.
Angew Chem Int Ed Engl ; 61(3): e202111670, 2022 Jan 17.
Artigo em Inglês | MEDLINE | ID: mdl-34668284

RESUMO

We report an effective strategy to enhance CO2 electroreduction (CER) properties of Cu-based Ruddlesden-Popper (RP) perovskite oxides by engineering their A-site cation deficiencies. With La2-x CuO4-δ (L2-x C, x=0, 0.1, 0.2, and 0.3) as proof-of-concept catalysts, we demonstrate that their CER activity and selectivity (to C2+ or CH4 ) show either a volcano-type or an inverted volcano-type dependence on the x values, with the extreme point at x=0.1. Among them, at -1.4 V, the L1.9 C delivers the optimal activity (51.3 mA cm-2 ) and selectivity (41.5 %) for C2+ , comparable to or better than those of most reported Cu-based oxides, while the L1.7 C exhibits the best activity (25.1 mA cm-2 ) and selectivity (22.1 %) for CH4 . Such optimized CER properties could be ascribed to the favorable merits brought by the cation-deficiency-induced oxygen vacancies and/or CuO/RP hybrids, including the facilitated adsorption/activation of key reaction species and thus the manipulated reaction pathways.

18.
Chemistry ; 27(15): 4869-4875, 2021 Mar 12.
Artigo em Inglês | MEDLINE | ID: mdl-33448047

RESUMO

The surface hydroxyl groups of Nix Cu1-x (OH)2 play a crucial role in governing their conversion efficiency into Nix Cu1-x Ox (OH)2-x during the electro-chemical pre-activation process, thus affecting the integral ammonia oxidation reaction (AOR) reactivity. Herein, the rational design of hierarchical porous NiCu double hydroxide nanotyres (NiCu DHTs) was reported for the first time by considering hydroxyl-rich interfaces to promote pre-activation efficiency and intrinsic structural superiority (i.e., annulus, porosity) to accelerate AOR kinetics. A systematic investigation of the structure-function relationship was conducted by manipulating a series of NiCu DHs with tunable intercalations and morphologies. Remarkably, the NiCu DHTs exhibit superior AOR activity (onset potential of 1.31 V with 7.52 mA cm-2 at 1.5 V) and high ammonia sensitivity (detection limit of 9 µm), manifesting one of the best non-noble metal AOR electrocatalysts and electro-analytical electrodetectors. This work deepens the understanding of the crucial role of surface hydroxyl groups on determining the catalytic performance in alkaline medium.

19.
J Magn Reson Imaging ; 53(6): 1744-1751, 2021 06.
Artigo em Inglês | MEDLINE | ID: mdl-33491233

RESUMO

The effects of morphologic abnormalities, including sigmoid sinus wall dehiscence (SSWD), transverse sinus stenosis (TSS), and sigmoid sinus diverticulum (SSD), on hemodynamics in venous pulsatile tinnitus (PT) patients have not been established. The aim of this study was to evaluate the effects of SSWD, TSS, and SSD on the hemodynamics of transverse-sigmoid sinus in venous PT patients. This was a prospective study with 44 venous PT patients and 12 healthy controls. A 3 T/four-dimensional (4D) flow magnetic resonance imaging with fast field echo was used. Computed tomography arteriography/venography was used to assess ipsilateral SSWD, TSS, and SSD. Maximum velocity (Vmax ), average velocity (Vavg ), and average flow (Flowavg ) were measured. Blood flow patterns were independently assessed by three neuroradiologists. One-way analysis of variance or Kruskal-Wallis test was also used. On the symptomatic side, all patients had SSWD, 33 patients had TSS, and 22 patients had SSD. Compared with healthy controls, patients with TSS, without TSS, with SSD, and without SSD all showed higher Vmax (all p < 0.050), Vavg (all p < 0.050), and Flowavg (all p < 0.050). Patients with TSS showed higher Vmax (p < 0.050) and Vavg (p < 0.050) than those without TSS, and no significant difference in Flowavg was found between the two groups (p = 0.408). No significant differences in Vmax , Vavg , and Flowavg were found between patients with and without SSD (all p = 1.000). Jet-like flow in the stenosis and downstream of the stenosis was observed in all patients with TSS. Vortex in SSD was observed in 15 patients with SSD (68%). High blood velocity and flow may be characteristic markers of venous PT. SSWD may be a necessary condition for venous PT. TSS may further increase the blood velocity and form a jet-like flow. SSD may be related to vortex formation but had no significant effect on blood velocity and flow. LEVEL OF EVIDENCE: 2 TECHNICAL EFFICACY STAGE: 3.


Assuntos
Zumbido , Cavidades Cranianas , Hemodinâmica , Humanos , Imageamento por Ressonância Magnética , Estudos Prospectivos , Zumbido/diagnóstico por imagem
20.
Eur Radiol ; 31(5): 2896-2902, 2021 May.
Artigo em Inglês | MEDLINE | ID: mdl-33128184

RESUMO

OBJECTIVES: To investigate the correlation between transverse sinus stenosis (TSS) and transstenotic pressure gradient (TPG) in unilateral pulsatile tinnitus (PT) patients with sigmoid sinus wall anomalies (SSWA). METHODS: Fifty-seven patients with unilateral venous PT were retrospectively included. All of them underwent CT venography and catheter manometry, accompanied with SSWA. The degree, length, shape (intrinsic/extrinsic/dysplasia), location (proximal/middle/distal, referring to the relative position of TSS and the Labbé vein junction) of TSS, the types of SSWA (dehiscence/diverticulum), and the degree of transverse sinus outflow laterality were assessed, and the correlations with ipsilesional TPG were analyzed. RESULTS: The mean value of ipsilesional TPG was 7.61 ± 0.52 mmHg. The degree and length of ipsilesional TSS were positively correlated with TPG (p < 0.001, p' < 0.001), respectively. TPG was significantly larger in patients with contralateral transverse sinus dysplasia than those without (p = 0.023) and significantly smaller in patients with ipsilesional sigmoid sinus diverticulum than those with isolated dehiscence (p = 0.001). No statistical difference in TPG was shown between ipsilesional TSSs of different shapes or locations (p > 0.05). No correlation was noted between the degree of ipsilesional transverse sinus outflow laterality and TPG (p = 0.051). Stepwise linear regression indicated that the degree (ß = 9.207, 95% CI = 3.558-14.856), length (ß = 0.122, 95% CI = 0.025-0.220) of ipsilesional TSS, and contralateral transverse sinus dysplasia (ß = 1.875, 95% CI = 0.220-3.530) were significantly correlated with TPG (R2 = 0.471). CONCLUSIONS: The degree, length of ipsilesional TSS, and contralateral transverse sinus dysplasia may be used to predict TPG in unilateral PT patients with SSWA. KEY POINTS: • CT venography may act as a screening tool to help low-probability unilateral pulsatile tinnitus (PT) patients with sigmoid sinus wall anomalies (SSWA) avoid invasive catheter manometry. • The degree and length of ipsilesional transverse sinus stenosis (TSS) are positively correlated with transtenotic pressure gradient (TPG) in unilateral PT patients with SSWA. • Ipsilesional TPG is larger in unilateral PT patients with contralateral transverse sinus dysplasia than those without and is smaller in unilateral PT patients with sigmoid sinus diverticulum than those with isolated dehiscence.


Assuntos
Zumbido , Constrição Patológica , Cavidades Cranianas/diagnóstico por imagem , Humanos , Flebografia , Estudos Retrospectivos , Zumbido/diagnóstico por imagem
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