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1.
Sci Total Environ ; 804: 150161, 2022 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-34517313

RESUMO

In this work, mesoporous poorly crystalline hematite (α-Fe2O3) was prepared using mesoporous silica (KIT-6) functionalized with 3-[(2-aminoethyl)amino]propyltrimethoxysilane as a hard template (SMPC-α-Fe2O3). The disordered atomic arrangement structure of SMPC-α-Fe2O3 promoted the formation of oxygen vacancies, which was confirmed using X-ray photoelectron spectroscopy (XPS), O2-temperature-programmed desorption (TPD), H2-temperature-programmed reduction (TPR), and in situ diffuse reflectance infrared Fourier transform (DRIFT) analyses. Density functional theory calculations (DFT) also proved that reducing the crystallinity of α-Fe2O3 decreased the formation energy of oxygen vacancies. TPD and in situ DRIFT analyses of NH3 adsorption suggested that the surface acidity of SMPC-α-Fe2O3 was considerably higher than those of mesoporous poorly crystalline α-Fe2O3 (MPC-α-Fe2O3) and highly crystalline α-Fe2O3 (HC-α-Fe2O3). The oxygen vacancies and acid sites formed on α-Fe2O3 surface are beneficial for ozone (O3) decomposition. Compared with MPC-α-Fe2O3 and HC-α-Fe2O3, SMPC-α-Fe2O3 exhibited a higher removal efficiency for 200-ppm O3 at a space velocity of 720 L g-1 h-1 at 25 ± 2 °C under dry conditions. Additionally, in situ DRIFT and XPS results suggested that the accumulation of peroxide (O22-) and the conversion of O22- to lattice oxygen over the oxygen vacancies caused catalyst deactivation. However, O22- could be desorbed completely by continuous N2 purging at approximately 350 °C. This study provides significant insights for developing highly active α-Fe2O3 catalysts for O3 decomposition.


Assuntos
Ozônio , Adsorção , Catálise , Oxigênio , Peróxidos
2.
J Am Chem Soc ; 2021 Nov 24.
Artigo em Inglês | MEDLINE | ID: mdl-34817997

RESUMO

Asymmetric functionalization of the C(sp3)-H bond is an attractive yet challenging strategy to achieve versatile bond-forming events, enabling the precise assembly of molecular complexity with minimal manipulation of functional groups. Here, we report an asymmetric C(sp3)-H/C(sp3)-H umpolung coupling of N-allylimine and coordinating α-aryl carbonyls by using chiral phosphoramidite-palladium catalysis. A wide variety of α-heteroaryl ketones and 2-acylimidazoles are nicely tolerated to open a convenient and tunable avenue for efficient synthesis of enantioenriched ß-amino-γ,δ-unsaturated carbonyl derivatives with high levels of regio- and stereoselectivities, capable of providing a key intermediate for asymmetric synthesis of Focalin. This protocol showcases an umpolung reactivity of the N-allylimines through a concerted proton and two-electron transfer process to cleave the allylic C-H bond, effectively complementing established methodology for allylic C-H functionalization. An inner-sphere allylation pathway for both α-heteroaryl carbonyls and 2-acylimidazoles to attack the π-allylpalladium species is suggested by computational studies and experimental facts, wherein the nitrogen coordination to the palladium center enables the preference of branched regioselectivity.

7.
Proc Natl Acad Sci U S A ; 118(46)2021 11 16.
Artigo em Inglês | MEDLINE | ID: mdl-34753820

RESUMO

The COVID-19 global pandemic and associated government lockdowns dramatically altered human activity, providing a window into how changes in individual behavior, enacted en masse, impact atmospheric composition. The resulting reductions in anthropogenic activity represent an unprecedented event that yields a glimpse into a future where emissions to the atmosphere are reduced. Furthermore, the abrupt reduction in emissions during the lockdown periods led to clearly observable changes in atmospheric composition, which provide direct insight into feedbacks between the Earth system and human activity. While air pollutants and greenhouse gases share many common anthropogenic sources, there is a sharp difference in the response of their atmospheric concentrations to COVID-19 emissions changes, due in large part to their different lifetimes. Here, we discuss several key takeaways from modeling and observational studies. First, despite dramatic declines in mobility and associated vehicular emissions, the atmospheric growth rates of greenhouse gases were not slowed, in part due to decreased ocean uptake of CO2 and a likely increase in CH4 lifetime from reduced NO x emissions. Second, the response of O3 to decreased NO x emissions showed significant spatial and temporal variability, due to differing chemical regimes around the world. Finally, the overall response of atmospheric composition to emissions changes is heavily modulated by factors including carbon-cycle feedbacks to CH4 and CO2, background pollutant levels, the timing and location of emissions changes, and climate feedbacks on air quality, such as wildfires and the ozone climate penalty.


Assuntos
Poluição do Ar , Atmosfera/química , COVID-19/psicologia , Gases de Efeito Estufa , Modelos Teóricos , COVID-19/epidemiologia , Dióxido de Carbono , Mudança Climática , Humanos , Metano , Óxidos de Nitrogênio , Ozônio
9.
Zool Res ; 42(6): 739-745, 2021 Nov 18.
Artigo em Inglês | MEDLINE | ID: mdl-34636193

RESUMO

The small-eared shrew genus Cryptotis is the third largest in the family Soricidae and occurs in North, Central, and northern South America. In Mexico and Central and South America, most species inhabit geographically isolated moist, montane habitats at middle and high elevations in a typical sky-island pattern. The 49 recognized species have been partitioned into as many as six species groups based on morphological and molecular phylogenetic studies. The relationships among these species groups are poorly resolved, and their evolutionary histories, including migration patterns and locomotor adaptations, remain unclear. Herein, we provide a new phylogeny incorporating complete mitochondrial genomes (mitogenomes) and supermatrix approach. We compared different evolutionary scenarios using approximately unbiased (AU), Kishino-Hasegawa (KH), and Shimodaira-Hasegawa (SH) statistical tests. The phylogenetic hypothesis based on mitogenomes revealed novel relationships supporting a basal position for the Cryptotis parvus-group in the genus, and a close relationship between C. gracilis and one clade of the C. thomasi-group. The former relationship is consistent with the least derived humerus morphology and northern distribution of the species. The latter relationship implies multiple migrations between Central and South America. The lack of fine resolution for the species group relationships may be due partly to the lack of taxon sampling. In contrast, multi-approach analyses suggest that the unresolved relationships may be a result of rapid diversification during the early stages of Cryptotis evolution.


Assuntos
Especiação Genética , Genômica , Filogenia , Musaranhos/classificação , Musaranhos/genética , Animais
10.
Biomolecules ; 11(9)2021 09 07.
Artigo em Inglês | MEDLINE | ID: mdl-34572534

RESUMO

A bacteriophage switches between lytic and lysogenic life cycles. The AimR-AimP-AimX communication system is responsible for phage lysis-lysogeny decisions during the infection of Bacillus subtilis. AimX is a regulator biasing phage lysis, AimR is a transcription factor activating AimX expression, and AimP is an arbitrium peptide that determines phage lysogeny by deactivating AimR. A strain-specific mechanism for the lysis-lysogeny decisions is proposed in SPbeta and phi3T phages. That is, the arbitrium peptide of the SPbeta phage stabilizes the SPbeta AimR (spAimR) dimer, whereas the phi3T-derived peptide disassembles the phi3T AimR (phAimR) dimer into a monomer. Here, we find that phAimR does not undergo dimer-to-monomer conversion upon arbitrium peptide binding. Gel-filtration, static light scattering (SLS) and analytical ultracentrifugation (AUC) results show that phAimR is dimeric regardless of the presence of arbitrium peptide. Small-angle X-ray scattering (SAXS) reveals that the arbitrium peptide binding makes an extended dimeric conformation. Single-molecule fluorescence resonance energy transfer (smFRET) analysis reveals that the phAimR dimer fluctuates among two distinct conformational states, and each preexisting state is selectively recognized by the arbitrium peptide or the target DNA, respectively. Collectively, our biophysical characterization of the phAimR dynamics underlying specific target recognition provides new mechanistic insights into understanding lysis-lysogeny decisions in Bacillus phage phi3T.

11.
Angew Chem Int Ed Engl ; 60(47): 24844-24848, 2021 11 15.
Artigo em Inglês | MEDLINE | ID: mdl-34519147

RESUMO

Chiral indoline-2-carboxylic acid has been identified to enable a highly enantioselective Catellani-type annulation of (hetero)aryl, alkenyl triflate and conjugated vinyl iodides with 4-(bromomethyl)cyclohexanone, directly assembling a diverse range of chiral all-carbon bridged ring systems. Control experiments and DFT calculations suggest that the coordinating orientation of the chiral amino acid to the arylpalladium(II) center allows for high levels of stereochemical control.

12.
Huan Jing Ke Xue ; 42(10): 4977-4987, 2021 Oct 08.
Artigo em Chinês | MEDLINE | ID: mdl-34581142

RESUMO

The aim of this study was to provide a reference for promoting ecological restoration of farmland and the green development of agriculture in the alluvial plain of the lower Yellow River by determining the effects of different rotation fallow patterns on the bacterial community of the fluvo-aquic soil. Farmland soil subject to a long-term rotation fallow experiment since 2018 was studied using Illumina MiSeq high-throughput sequencing technology, and the 'Tax4Fun' bacterial function prediction tool was used to analyze differences in soil bacterial community structure and function under the following four rotation fallow regimes:long fallow(LF), winter wheat and summer fallow(WF), winter fallow and summer maize(FM), and annual rotation of winter wheat and summer maize(WM). The environmental factors affecting changes in the soil bacterial community structure and function were also analyzed. In total, 44 phyla, 146 classes, 338 orders, 530 families, 965 genera, and 2073 species of bacteria were detected in the soil samples from the different rotation fallow regimes, and the dominant bacterial groups were Actinobacteria, Proteobacteria, Acidobacteria, and Chloroflexi in 0-20 cm and 20-40 cm soil layers. However, the relative abundances of the dominant bacteria groups were varied between the rotation fallow regimes. In the 0-20 cm layer of the seasonal fallow soils(WF and FM), bacteria were more abundant and community diversity was higher than that of the WM and LF soils. In 20-40 cm soil layer, the WF soil was more abundant in bacterial and the community was more diverse. Based on the prediction function of the 'Tax4Fun' tool, six primary metabolic pathways, 40 secondary metabolic pathways(18 types with relative abundance greater than 1%), and 264 tertiary metabolic pathways were identified in the soil bacteria of the different rotation fallow regimes. Seasonal fallow(WF and FM) was found to increase the relative abundance of beneficial bacterial metabolic pathways involved in metabolism, environmental information processing, and genetic information processing. According to RDA analysis, the soil bacterial community in the 0-20 cm soil layer was significantly affected by soil moisture, total phosphorus, available phosphorus, available potassium, pH, and C/N ratio(P<0.05), and the soil bacterial community in 20-40 cm soil layer was significantly affected by soil total phosphorus and available phosphorus(P<0.05). Therefore, different fallow patterns were linked to variation in the structure, diversity, and metabolic functions of soil bacterial communities. Based on these results, seasonal fallow practices could promote the health and stability of farmland soil ecosystems.


Assuntos
Ecossistema , Solo , Bactérias/genética , Produção Agrícola , Humanos , Microbiologia do Solo
13.
PeerJ ; 9: e12058, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34589297

RESUMO

Endogenous hydrogen sulfide (H2S) is generated in many metabolism pathways, and has been recognized as a second messenger against antibiotics and reactive oxygen species (ROS). In Aeromonas veronii, Small Protein B (SmpB) plays an important role in resisting stress. The absence of smpB could trigger sulfate assimilation pathway to adapt the nutrient deficiency, of which was mediated by up-regulation of cbl and cys genes and followed with enhancing H2S production. To figure out the mutual regulations of cbl and cys genes, a series of experiments were performed. Compared with the wild type, cysH was down-regulated significantly in cbl deletion by qRT-PCR. The fluorescence analysis further manifested that Cbl had a positive regulatory effect on the promoter of cysJIH. Bacterial one-hybrid analysis and electrophoretic mobility shift assay (EMSA) verified that Cbl bound with the promoter of cysJIH. Collectively, the tolerance to adversity could be maintained by the production of H2S when SmpB was malfunctioned, of which the activity of cysJIH promoter was positively regulated by upstream Cbl protein. The outcomes also suggested the enormous potentials of Aeromonas veronii in environmental adaptability.

14.
Front Vet Sci ; 8: 692389, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34490392

RESUMO

Lactobacillus delbrueckii is a Gram-positive bacterium mostly used in the dairy industry for yogurt and cheese. The present study was designed to evaluate the effects of Lactobacillus delbrueckii on serum biochemical parameters, intestinal morphology, and performance by supplementing at a dietary level of 0.1% in diets for weaned piglets. Eighty healthy weaned piglets (initial body weight: 7.56 ± 0.2 kg) were randomly divided into two feeding groups with four replicates in each group (n = 10 animals per replicate); piglets were fed with basal diet (CON) or basal diet containing 0.1% Lactobacillus delbrueckii (LAC). The results showed that dietary supplementation of Lactobacillus delbrueckii improved growth performance and increased serum HDL and insulin levels in piglets on the 28th day of the experimental time (p < 0.05). The gut microbe analysis revealed that Lactobacillus delbrueckii significantly decreased the relative abundance of the phyla Bacteroidetes, but increased the relative abundance of the phyla Firmicutes. The Lactobacillus delbrueckii also significantly increased the relative abundance of Bifidobacterium and Lactobacillus at the genus level of the bacterial community in the ileum, but decreased the relative abundance of unclassified Clostridiales. Moreover, Lactobacillus delbrueckii improved mucosal morphology by obtaining higher intestinal villus height (p < 0.05), significantly increasing the concentrations of butyrate, isobutyric acid, and isovaleric acid in colonic chyme of piglets, but decreasing the intestinal pH at the duodenum and ileum on the 28th day of the experimental time. In conclusion, dietary supplementation of Lactobacillus delbrueckii in the diet of weaned piglets can improve intestinal morphology and modulate the microbiota community to promote growth performance.

15.
J Agric Food Chem ; 69(37): 10885-10892, 2021 Sep 22.
Artigo em Inglês | MEDLINE | ID: mdl-34494818

RESUMO

Broccoli-derived peptides show beneficial metabolic effects, and it is necessary to examine their exact functional sequences. First, peptides from the trypsin hydrolysate of broccoli proteins were isolated and identified using column chromatography and quadrupole time-of-flight mass spectrometry. After that, their functions were verified by oral administration. The results identified two novel peptides as Leu-Pro-Gly-Val-Leu-Pro-Val-Ala (LPGVLPVA) and Tyr-Leu-Tyr-Ser-Pro-Ala-Tyr (YLYSPAY). LPGVLPVA exhibited an ACE IC50 value of 0.776 ± 0.03 µM and a DPP-IV IC50 value of 392 ± 24 µM; YLYSPAY showed an ACE IC50 value of 8.52 ± 0.63 µM and a DPP-IV IC50 value of 181 ± 4 µM. Administration of the peptides reduced the blood pressure of spontaneously hypertensive rats and reduced blood glucose levels in the oral glucose tolerance test in mice. The results indicated that LPGVLPVA and YLYSPAY could be potential nutritional candidates for hypertensive and diabetic people, especially for those with diabetes associated with hypertension.


Assuntos
Inibidores da Enzima Conversora de Angiotensina , Brassica , Inibidores da Dipeptidil Peptidase IV , Angiotensina I , Animais , Brassica/química , Camundongos , Peptídeos , Ratos , Tripsina
16.
Zhongguo Dang Dai Er Ke Za Zhi ; 23(8): 828-834, 2021 Aug 15.
Artigo em Inglês, Chinês | MEDLINE | ID: mdl-34511173

RESUMO

OBJECTIVES: To study the expression of adipokines in children with primary nephrotic syndrome (PNS) before and after treatment and its correlation with blood lipids, as well as the role of adipokines in PNS children with hyperlipidemia. METHODS: A total of 90 children who were diagnosed with incipient PNS or recurrence of PNS after corticosteroid withdrawal for more than 6 months were enrolled as subjects. Thirty children who underwent physical examination were enrolled as the control group. Venous blood samples were collected from the children in the control group and the children with PNS before corticosteroid therapy (active stage) and after urinary protein clearance following 4 weeks of corticosteroid therapy (remission stage). ELISA was used to measure the levels of adipokines. An automatic biochemical analyzer was used to measure blood lipid levels. RESULTS: Compared with the control group, the children with PNS had a significantly lower level of omentin-1 in both active and remission stages, and their level of omentin-1 in the active stage was significantly lower than that in the remission stage (P<0.001). For the children with PNS, the level of chemerin in the active stage was significantly higher than that in the remission stage, and the children with PNS in the active stage had a significantly higher level of chemerin than the control group (P<0.001). For the children with PNS, atherogenic index of plasma, atherogenic coefficient (AC), castelli risk index-1 (CRI-1), castelli risk index-2 (CRI-2), and non-high-density lipoprotein in the active stage were significantly higher than those in the remission stage (P<0.001), and these indices in the children with PNS in the active stage were significantly higher than those in the control group (P<0.001). The children with PNS in the remission stage had significantly higher atherogenic index of plasma, AC, CRI-1, and non-high-density lipoprotein than the control group (P<0.001). Compared with the control group, the children with PNS in the remission stage had significantly higher serum levels of total cholesterol, triglyceride, high-density lipoprotein, low-density lipoprotein, apolipoprotein B, and apolipoprotein A (P<0.01). In the children with PNS, the ratio of omentin-1 before and after corticosteroid therapy was positively correlated with that of high-density lipoprotein, 24-hour urinary protein excretion, and high-density lipoprotein/apolipoprotein A before and after treatment, and it was negatively correlated with the ratio of AC and CRI-1 before and after treatment (P<0.05). The PNS children with low omentin-1 levels in the active stage had significantly higher levels of CRI-1, CRI-2, AC, and apolipoprotein B/apolipoprotein A ratio than those with high omentin-1 levels (P<0.05). CONCLUSIONS: Omentin-1 may be associated with disease activity, dyslipidemia, and proteinuria in children with PNS. Blood lipid ratios may be more effective than traditional blood lipid parameters in monitoring early cardiovascular risk in children with PNS.


Assuntos
Citocinas/metabolismo , Hiperlipidemias , Lectinas/metabolismo , Síndrome Nefrótica , Adipocinas , Quimiocinas , Criança , Citocinas/genética , Proteínas Ligadas por GPI/genética , Proteínas Ligadas por GPI/metabolismo , Humanos , Lectinas/genética , Lipídeos , Síndrome Nefrótica/tratamento farmacológico , Proteinúria
17.
Theriogenology ; 173: 211-220, 2021 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-34399385

RESUMO

Although it is known that stresses on females damage oocytes with increased production of stress hormones, whether corticotrophin-releasing hormone (CRH) or adrenocorticotropic hormone (ACTH) harm oocytes directly are largely unknown. We demonstrated that CRH exposure during in vitro maturation impaired competence of both pig and mouse cumulus-oocyte-complexes (COCs), and it impaired competence and induced apoptosis in pig cumulus-denuded oocytes (DOs) but not in mouse DOs. CRH receptor 1 was expressed in pig DOs and in cumulus cells (CCs) of both species but not in mouse DOs. In the presence of CRH, whereas mouse CCs underwent apoptosis, pig CCs did not. While pig CCs did, mouse CCs did not express CRH-binding protein. ACTH did not affect competence of either pig or mouse COCs or DOs although they all expressed ACTH receptor. Both pig and mouse CCs expressed steroidogenic acute regulatory protein (StAR), and ACTH enhanced their progesterone production while alleviating their apoptosis. Neither pig nor mouse DOs expressed StAR, but ACTH inhibited maturation-promoting factor and decelerated meiotic progression of DOs suggesting activation of protein kinase A (PKA). In conclusion, CRH impaired pig and mouse oocyte competence by interacting with CRH receptor and inducing CCs apoptosis, respectively. ACTH activated PKA in both DOs and CCs although it showed no effect on oocyte competence.


Assuntos
Hormônio Adrenocorticotrópico , Hormônio Liberador da Corticotropina , Hormônio Adrenocorticotrópico/farmacologia , Animais , Técnicas de Cocultura/veterinária , Células do Cúmulo , Feminino , Técnicas de Maturação in Vitro de Oócitos/veterinária , Camundongos , Oócitos , Suínos
19.
Light Sci Appl ; 10(1): 168, 2021 Aug 18.
Artigo em Inglês | MEDLINE | ID: mdl-34408125

RESUMO

Single-atom catalysts (SACs) with atomically dispersed catalytic sites have shown outstanding catalytic performance in a variety of reactions. However, the development of facile and high-yield techniques for the fabrication of SACs remains challenging. In this paper, we report a laser-induced solid-phase strategy for the synthesis of Pt SACs on graphene support. Simply by rapid laser scanning/irradiation of a freeze-dried electrochemical graphene oxide (EGO) film loaded with chloroplatinic acid (H2PtCl6), we enabled simultaneous pyrolysis of H2PtCl6 into SACs and reduction/graphitization of EGO into graphene. The rapid freezing of EGO hydrogel film infused with H2PtCl6 solution in liquid nitrogen and the subsequent ice sublimation by freeze-drying were essential to achieve the atomically dispersed Pt. Nanosecond pulsed infrared (IR; 1064 nm) and picosecond pulsed ultraviolet (UV; 355 nm) lasers were used to investigate the effects of laser wavelength and pulse duration on the SACs formation mechanism. The atomically dispersed Pt on graphene support exhibited a small overpotential of -42.3 mV at -10 mA cm-2 for hydrogen evolution reaction and a mass activity tenfold higher than that of the commercial Pt/C catalyst. This method is simple, fast and potentially versatile, and scalable for the mass production of SACs.

20.
Chem Commun (Camb) ; 57(55): 6748-6751, 2021 Jul 14.
Artigo em Inglês | MEDLINE | ID: mdl-34236350

RESUMO

Asymmetric allylic C-H alkylation of 1,4-pentadienes with α-angelica lactones has been developed by tri-axial phosphoramidite-palladium catalysis. This reaction can tolerate a range of functional groups under mild conditions, furnishing versatile chiral γ,γ-disubstituted butenolides in high yields with good to high levels of stereoselectivity.

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